| The fresh version (plums) and the dried version (prunes) of the plant scientifically known as Prunus domestica have been the subject of repeated health research for their high content of unique phytonutrients called neochlorogenic and chlorogenic acid. These substances found in prunes and plums are classified as phenols, and their function as antioxidants has been well documented. These damage-preventing substances are particularly effective in neutralizing a particularly dangerous oxygen radical called superoxide anion radical, and they have also been shown to help prevent oxygen-based damage to fats. Since our cell membranes, brain cells and molecules such as cholesterol are largely composed of fats, preventing free radical damage to fats is no small benefit. |
| Beta-Carotene for Even More Antioxidant Protection |
| Prunes' ability to deter oxygen-related damage to our cells is also related to their beta-carotene content. Prunes emerged from our food ranking system as a good source of vitamin A (in the form of beta-carotene)-just a quarter-cup of prunes will give you 16.9% of the daily value for vitamin A. Beta-carotene acts as a fat-soluble antioxidant,eliminating free radicals that would otherwise cause a lot of damage to our cells and cell membranes. Only after cholesterol has been oxidized by free radicals does it pose a threat to artery walls. The build-up of cholesterol in the artery walls forms plaques that can either grow so large they block blood flow or rupture, releasing a clot that can impede the flow of blood, and triggering a heart attack or stroke. Free radicals can also damage cellular DNA, causing mutations which, if serious enough, can result in the formation of cancerous cells. In addition, by causing damage, free radicals contribute to inflammation, which is one way the body clears out cells or other substances that have been damaged. In this way, free radicals increase the severity of a number of different conditions. This is why beta-carotene, which shuts down free radicals, has been shown in studies to be helpful for the prevention of a variety of diseases, including atherosclerosis, diabetic heart disease, and colon cancer, and why it has also been found useful for reducing the severity of inflammatory conditions like asthma, osteoarthritis, and rheumatoid arthritis. |
| Potassium for Cardiovascular Health |
| Prunes are a good source of potassium, providing 9.0% of the daily value for this mineral in a quarter-cup. Potassium is an essential mineral for maintaining normal blood pressure and heart function. Since a quarter cup of prunes contains a whopping 316.6 mg of potassium and only 1.7 mg of sodium, those diced dried prunes on top of your breakfast cereal may help to prevent high blood pressure and protect against atherosclerosis. |
| The effectiveness of potassium-rich foods like prunes in lowering blood pressure has been demonstrated by a number of studies. For example, researchers tracked over 40,000 American male health professionals over four years to determine the effects of diet on blood pressure. Men who ate diets higher in potassium-rich foods, as well as foods high in magnesium and cereal fiber, had a substantially reduced risk of stroke. |
| In addition to these cardiovascular benefits, the potassium found in prunes may also help to promote bone health. Potassium may counteract the increased urinary calcium loss caused by the high-salt diets typical of most Americans, thus helping to prevent bones from thinning out at a fast rate. |
| Prunes are widely known as a good source of dietary fiber, a reputation that was confirmed in our ranking system in which prunes were found to supply 12.1% of the daily value for fiber in just a quarter-cup. The health benefits provided by prunes' fiber are substantial: |
| Normalizing Blood Sugar Levels and Helping with Weight Loss |
| Prunes' soluble fiber helps normalize blood sugar levels by slowing the rate at which food leaves the stomach and by delaying the absorption of glucose (the form in which sugar is transported in the blood) following a meal. Soluble fiber also increases insulin sensitivity and can therefore play a helpful role in the prevention and treatment of type 2 diabetes. And, prunes' soluble fiber promotes a sense of satisfied fullness after a meal by slowing the rate at which food leaves the stomach, so prunes can also help prevent overeating and weight gain. |
| Prunes' Fiber for Regularity, Lower Cholesterol, & Intestinal Protection |
| Prunes are well known for their ability to prevent constipation. In addition to providing bulk and decreasing the transit time of fecal matter, thus decreasing the risk of colon cancer and hemorrhoids, prunes' insoluble fiber also provides food for the "friendly" bacteria in the large intestine. When these helpful bacteria ferment prunes' insoluble fiber, they produce a short-chain fatty acid called butyric acid, which serves as the primary fuel for the cells of the large intestine and helps maintain a healthy colon. These helpful bacteria also create two other short-chain fatty acids, propionic and acetic acid, which are used as fuel by the cells of the liver and muscles. |
| The propionic acid produced from prunes' insoluble fiber may also be partly responsible for the cholesterol-lowering properties of fiber. In animal studies, propionic acid has been shown to inhibit HMG-CoA reductase, an enzyme involved in the production of cholesterol by the liver. By lowering the activity of this enzyme, propionic acid helps lower blood cholesterol levels. |
| In addition, prunes' soluble fibers help to lower cholesterol by binding to bile acids and removing them from the body via the feces. Bile acids are compounds used to digest fat that are manufactured by the liver from cholesterol. When they are excreted along with prunes' fiber, the liver must manufacture new bile acids and uses up more cholesterol, thus lowering the amount of cholesterol in circulation. Soluble fiber may also reduce the amount of cholesterol manufactured by the liver. |
| A study published in the Archives of Internal Medicine confirms that eating high fiber foods, such as prunes, helps prevent heart disease. Almost 10,000 American adults participated in this study and were followed for 19 years. People eating the most fiber, 21 grams per day, had 12% less coronary heart disease (CHD) and 11% less cardiovascular disease (CVD) compared to those eating the least, 5 grams daily. Those eating the most water-soluble dietary fiber fared even better with a 15% reduction in risk of CHD and a 10% risk reduction in CVD. |
| Lastly, the insoluble fiber provided by prunes feed friendly bacteria in the digestive tract, which helps to maintain larger populations of friendly bacteria. In addition to producing the helpful short-chain fatty acids described above, friendly bacteria play an important protective role by crowding out pathogenic (disease-causing) bacteria and preventing them from surviving in the intestinal tract. |
| Fruit and Cereal Fiber Protective against Postmenopausal Breast Cancer |
| Results of a prospective study involving 51,823 postmenopausal women for an average of 8.3 years showed a 34% reduction in breast cancer risk for those consuming the most fruit fiber compared to those consuming the least. In addition, in the subgroup of women who had ever used hormone replacement, those consuming the most fiber, especially cereal fiber, had a 50% reduction in their risk of breast cancer compared to those consuming the least. |
| Fruits richest in fiber include apples, dates, figs, pears and prunes. When choosing a high fiber cereal, look for whole grain cereals as they supply the most bran (a mere 1/3rd cup of bran contains about 14 grams of fiber). |
| Iron Absorption |
| The ability of plum and prune to increase absorption of iron into the body has also been documented in published research. The ability of plum and prune to make iron more available may be related to the vitamin C content of this fruit. |
| Prunes are nutritious fruits that are extremely fun to eat since they have a sweet, deep taste and a sticky, chewy texture. Prunes are actually dried plums, more specifically the dried version of European plums, including the Agen variety. |
| Unfortunately for the delicious and quite beneficial prune, its name has acquired a somewhat negative connotation, being associated with wrinkles, old age and sluggish gastrointestinal tracts. As our Health Benefits section shows, nothing could be further from the truth. To give prunes some PR that may help overcome this stigma and to promote prunes to their rightful place in the American diet, they have been informally christened with another name, a name that reflects their heritage . . . the "dried plum." |
| The scientific name for plums and prunes is Prunus domestica. |
| The process of drying plums to make prunes is thought to have originated thousands of years ago in an area near the Caspian Sea, the same region where the prune-producing European plums originated. They spread throughout Europe with the migration of different cultures and civilizations. |
| The process of drying plums to produce prunes took hold in California, now the leading producer of prunes worldwide, in the mid-19th century when Louis Pellier planted grafted plum tree cuttings brought back with him from his native France. Among these trees were those belonging to the Agen variety, the type of plum that is extremely well suited to be dried to make prunes. |
| Prunes are sold either with their pits or already pitted. The form you choose should depend upon your personal preference and recipe needs. |
| Ideally, you should purchase prunes that are sold in transparent containers so that you can evaluate them for quality. They should be plump, shiny, relatively soft and free of mold. If the packages are opaque, ensure that they are tightly sealed so that the prunes will not have lost any moisture. As with any other dried fruit, try to purchase prunes that are not processed with food preservatives such as sulfites. |
| Prunes should be stored in an airtight container in a cool, dry and dark place where they will keep for several months. Storing them in the refrigerator will extend their freshness, allowing them to keep for about six months. Regardless of where you store them, make sure that when you open the container, you reseal it tightly to prevent the prunes from losing moisture. |
| For some of our favorite recipes, click Recipes. |
| Tips for Preparing Prunes: |
| If you have prunes that are extremely dry, soaking them in hot water for a few minutes will help to refresh them. If you are planning on cooking the prunes, soaking them in water or juice beforehand will reduce the cooking time. |
| A Few Quick Serving Ideas: |
| Serve stewed prunes with rosemary-scented braised lamb and enjoy this Middle Eastern inspired meal. |
| Serve stewed or soaked prunes on top of pancakes and waffles. |
| Combine diced dried prunes with other dried fruits and nuts to make homemade trail mix. |
| Prunes make a delicious addition to poultry stuffing. |
| Prunes and Oxalates |
| Prunes are among a small number of foods that contain measurable amounts of oxalates, naturally-occurring substances found in plants, animals, and human beings. When oxalates become too concentrated in body fluids, they can crystallize and cause health problems. For this reason, individuals with already existing and untreated kidney or gallbladder problems may want to avoid eating prunes. Laboratory studies have shown that oxalates may also interfere with absorption of calcium from the body. Yet, in every peer-reviewed research study we've seen, the ability of oxalates to lower calcium absorption is relatively small and definitely does not outweigh the ability of oxalate-containing foods to contribute calcium to the meal plan. If your digestive tract is healthy, and you do a good job of chewing and relaxing while you enjoy your meals, you will get significant benefits-including absorption of calcium-from calcium-rich foods plant foods that also contain oxalic acid. Ordinarily, a healthcare practitioner would not discourage a person focused on ensuring that they are meeting their calcium requirements from eating these nutrient-rich foods because of their oxalate content. For more on this subject, please see "Can you tell me what oxalates are and in which foods they can be found?" |
quinta-feira, 22 de maio de 2014
Prunes and Plums
A importância das proteinas
|
|
Muita gente pensaria em carne, peixe, ovos, e queijos como as principais fontes de proteínas, embora alguns com uma extrita dieta vegetariana, relacionaria muitas diferentes fontes, como castanhas, ervilhas e feijões.
Ovos são usualmente considerados como um alimento de alto teor protéico, embora contenha sómente 12 % de proteina. Voce poderia sugerir alguma razão porque este valor é aparentemente tão baixo ? Pense na composição física do interior do ovo, comparado com os alimentos de alto teor protéico relacionados na tabela..
Embora as informações nos pacotes de alimentos relacione as proteinas como se fossem simples substâncias, existem dezenas de milhares de diferentes tipos de proteinas nos organismos vivos. A vida é baseada em proteinas, e a palavra “proteina” é derivada de uma palavra grega que significa, “ conservando o primeiro lugar” . As proteinas formam uma parte integral dos componentes de todas as células vivas, e uma típica célula no corpo humano contém 18% de proteina, embora alguns tipos de células, tais como as células musculares, contenham muito mais. De fato, a maioria dos alimentos, que nós chamamos carne, é na verdade músculo. Algumas proteinas tem um enorme papel estrutural no corpo, formando tendões e cabelos, outras são produzidas no interior e então liberadas das células, ( secretadas ) e funcionam como enzimas e hormônios. As proteínas que nós comemos são digeridas por enzimas, que são por si só, proteinas. Alguns tipos de proteinas formam parte do sistema imunológico, que nos protege contra infecções, enquanto outras desempenham um papel vital na coagulação do sangue. Entretanto, todas elas tem a mesma estrutura fundamental. Elas são feitas de pequenas moléculas chamadas aminoácidos. Grande moléculas compostas de pequenas subunidades são chamadas polímeros, e as subunidades, neste caso, os aminoácidos, são os monômeros.. Então, preteinas poliméricas são fabricadas de aminoácidos monômeros.
A má postura pode ser pivô de várias lesões.
Dores lombares, hérnias discais, enxaquecas, dentre outras dores causadas pela postura irregular, trazem o desespero e a incapacitação para o trabalho e lazer de milhões de pessoas no mundo, provocando enormes prejuízos à saúde, à economia e à qualidade de vida como um todo.
Para tratar destes problemas, alguns profissionais da área da saúde têm estudado e aplicado a posturologia – método desenvolvido pelo cirurgião-ortopedista francês, Dr. Bernard Bricot. Trata-se de uma nova abordagem de diagnóstico e tratamento multidisciplinar, que reúne várias especialidades como: clínica geral, oftalmologia, fisioterapia, odontologia, fonoaudiologia, ortopédica, podologia, e outros.
O foco é o tratamento da causa e não dos sintomas, fazendo a reprogramação postural através da correção dos captores que freqüentemente estão desregulados (olhos, pés, pele, dentes, músculos, articulações etc). “É preciso antes de tratar os sintomas das doenças, tentar corrigir a causa que gerou aquela patologia. A Posturologia não é uma nova Medicina, e sim uma nova forma de abordagem dela”, pondera Bricot.
Em Curitiba, o ortodontista e ortopedista facial, Paulo Stroparo, que estuda e aplica este método, relata o caso de uma paciente de 4 anos, que apresentava sérios problemas de oclusão. “Fiz uma avaliação mais completa. Devido à mordida cruzada, a postura da cabeça e dos ombros da menina não estava correta. Como os pais dela buscaram o tratamento cedo, além de ter sido mais rápido, evitou que ela tivesse problemas mais graves no futuro, como falta de equilíbrio, encurtamento dos músculos, dentre outros”, alerta.
Na avaliação de Stroparo, o importante é procurar um profissional qualificado para se ter um bom diagnóstico. “Na avaliação postural, é imprescindível saber analisar o sistema manducatório (dentes, músculos, articulações). O dentista também tem de saber avaliar a postura colaborando no trabalho da equipe, porque se há um desequilíbrio nela, este tem que ser diagnosticado e corrigido”.
15 coisas inventadas ou descobertas por acaso
Acidentes acontecem e alguns deles acabaram revelando produtos famosos e até provocando revoluções médicas e tecnológicas.
A maioria das invenções e descobertas da história foi obtida com muito esforço, pesquisa e trabalho. Mas bastaram alguns acidentes na vida de algumas pessoas para produtos surgirem e soluções serem desvendadas, como o Viagra, o marca-passo e até o picolé. Conheça alguns dos acasos mais famosos da humanidade e os seus resultados.
1. Corn flakes (flocos de milho)
Em 1894, os irmãos John Harvey Kellogg e Will Keith Kellogg estavam desenvolvendo novos alimentos para um grupo de pacientes de uma igreja adventista americana. Ao preparar a massa de trigo para fazer granola, Will deixou um pouco dela descansando, e quando voltou, estava ressecada.
Em vez de jogá-la fora, os irmãos a passaram pelos cilindros para afiná-la, esperando fazer longas folhas de massa de pão. Conseguiram flocos. Eles assaram os flocos, que se tornaram um grande hit entre os pacientes, e patentearam sob o nome de Granose. Os irmãos experimentaram fazer os flocos com vários grãos, inclusive milho, e em 1906 Will criou a empresa Kelloggs.
2. Picolé
Em 1905, com apenas 11 anos, Frank Epperson estava na varanda de sua casa preparando um refresco, com uma mistura de refrigerante em pó e água, quando alguém o chamou e ele esqueceu sua bebida ali. Na manhã seguinte, Epperson viu que o refresco estava congelado juntamente com um palito que ele usou para mexer o líquido. Foi assim que ele "criou" o picolé, patenteando o produto apenas em 1923.
3. Café
Uma das histórias mais aceitas e divulgadas quanto a origem do café é a do pastor Kaldi, que viveu na Etiópia há cerca de mil anos e observou que suas cabras estavam bem elétricas. Kaldi acabou notando que elas mastigavam os frutos de café no campo e logo associou as duas coisas.
O pastor comentou com um monge, que decidiu experimentar o poder dos frutos utilizando-os em forma de infusão, e ele percebeu que a bebida ajudava a resistir ao sono enquanto orava em suas longas horas de preces.
4. Batata chips
Tudo começou com a reclamação insistente de um cliente no restaurante do chefe George Crum, em 1853. Ele solicitou várias vezes para trocar as batatas fritas que pediu alegando que elas eram grossas e sem sal. Crum se irritou e as cortou em tiras extremamente finas, fritou até elas ficarem bem crocantes e adicionou um tempero extra de sal. O produto foi um sucesso.
5. Micro-ondas
Um dos itens mais high tech da cozinha foi descoberto por Percy Spencer em 1945, quando trabalhava em uma empresa de radares em uma experiência com – adivinhe – micro-ondas. Spencer notou que a barra de chocolate do seu bolso tinha derretido. Dali para a criação de um forno de micro-ondas foi um passo. O primeiro tinha 1,70 metro de altura e pesava 340 quilos.
6. Mola maluca
Se você é um leitor ávido do Tecmundo, deve saber que já existe uma fantasia de mola maluca. Mas o que você provavelmente não sabe é que ela foi inventada por um engenheiro naval, em 1943. Richard James bateu por acidente em uma mola mecânica e a viu “andar” pela sala. Depois do ocorrido, ele começou a trabalhar em um material para a fabricação do brinquedo, ao perceber seu potencial. A original é feita com fios de aço, e chama-se Slinky (que significa “elegante” e “gracioso”) nos Estados Unidos.
7. Massinha de modelar
O produto foi desenvolvido originalmente como produto de limpeza para wallpapers mas se tornou um dos brinquedos mais populares para crianças. A invenção é de Noah McVicher, que trabalhava em uma empresa de sabão na década de 30 e notou a semelhança do produto de limpeza com massas de modelar, mas sem a toxidade apresentada por elas até então. O brinquedo foi chamado de Play-Doh e é vendido até hoje pela Hasbro. Outras tantas massas genéricas também são comercializadas.
8. Cookies de chocolate
Ruth Wakefield era dona da Toll House Inn, uma espécie de parada e restaurante com comida caseira na beira de uma rodovia americana. Em um dia, ela estava fazendo biscoitos comuns, quando descobriu que estava sem chocolate em pó para fazer a massa. Ruth então decidiu colocar pedaços de chocolate meio-amargo sobre os biscoitos, pensando que eles iriam derreter e misturar-se a massa. Isso não aconteceu, e os biscoitos até então diferentes tornaram-se um sucesso imediato.
9. Penicilina
A penicilina nada mais é que uma substância com efeito bactericida produzida por um fungo. Ela foi acidentalmente descoberta em 1928 por Alexander Fleming, que saiu de férias e esqueceu algumas placas com cultura de microrganismos em seu laboratório, no hospital St. Mary, em Londres. Quando voltou da viagem, ele reparou que uma de suas culturas de Staphylococus tinha sido contaminada por um bolor... E não havia mais bactérias em volta das colônias. O bolor era o fungo produtor da penicilina e revolucionou a medicina.
10. Sacarina
O ano era 1879 e um pesquisador chamado Constantino Fahlberg tinha se esquecido de lavar as mãos antes do almoço. Ele derramara um produto químico em suas mãos, que adicionou um sabor doce incomum ao pão que ele comeu. Era a sacarina, que se tornaria popular somente durante a Primeira Guerra Mundial, com o racionamento do açúcar. Só em 1960 ela seria usada na fabricação de adoçantes e refrigerantes diets.
11. Fogos de artifício
Os fogos de artifício tiveram origem na China, há cerca de 2 mil anos. Diz a lenda que eles foram inventados por acidente, quando um cozinheiro misturou carvão, enxofre e salitre, itens comuns encontrados em cozinhas naquela época. A combinação foi esquentada e, quando foi comprimida dentro de um tubo de bambu, explodiu.
12. Viagra
O Viagra é conhecido como pílula azul, vitamina V e salvador de casamentos, e sua descoberta aconteceu enquanto os farmacêuticos do laboratório Pfizer sintetizavam o Cidrato de Sidenafila para tratar a hipertensão. Os primeiros testes revelaram uma forte ereção peniana com o uso do produto... Pronto, estava criado o primeiro e mais popular remédio para disfunção erétil da história.
13. Insulina
A remoção do pâncreas de um cão saudável acabou na descoberta da Insulina. Dois médicos extraíram-no em 1889 para demonstrar o papel do órgão na digestão dos alimentos, e vários dias depois o guarda do cão reparou que havia muitas moscas alimentando-se da urina do animal. Ao fazer um teste de urina, verificou-se que havia açúcar presente, demonstrando pela primeira vez a relação entre pâncreas e diabetes. Depois de muitas pesquisas, a insulina seria criada.
14. Supercola (cola instantânea, Super Bonder)
Tudo começou com um projeto para a criação de um tipo de mira de precisão a partir de uma forma experimental de plástico transparente durante a Segunda Guerra Mundial, em 1945, sob a liderança do Dr. Harry Coover. Mas a substância era extremamente pegajosa e revelou-se difícil de trabalhar.
Seis anos depois, Coover foi transferido para a fábrica da Kodak e percebeu que a substância tinha propriedades únicas. Nos experimentos que fez, ele viu que ela colava rapidamente e de maneira forte. A supercola estava criada.
15. Marca-passo
Em 1956, Wilson Greatbatch, um professor de engenharia na Universidade de Buffalo, estava construindo um dispositivo que poderia gravar ritmos cardíacos. Sem querer, o aparelho acabou fazendo o contrário, emitindo uma série de pulsos elétricos que se assemelhavam aos ritmos, e dessa maneira o primeiro marca-passo foi criado.
Chevrolet Impala 2015
O Chevrolet Impala 2015 chega ao mercado americano com uma boa novidade: sistema de desligamento automático do motor, mais conhecido como Start&Stop. O item vem de série no sedã americano, mas apenas na versão 2.5 Ecotec com 195 cv e 25,7 kgfm.
Com isso, a média de consumo do Chevrolet Impala 2015 melhor apenas um pouco, sendo que na cidade faz 9,4 km/litro e na estrada 13,2 km/litro. Anteriormente, o sedã fazia 8,9 km/litro no circuito urbano. O isolamento acústico foi sensivelmente melhorado e o motor de arranque é mais potente.
Drones present may legal, ethical concerns, experts say
The use of so-called drones -- unmanned aircraft -- for domestic security purposes, surveillance of citizens and putative criminals and organizations raises many legal and ethical concerns particularly with regard to the Fourth Amendment to the US Constitution, Council of Europe instruments, and the EU Data Protection Framework, according to a research paper published in the International Journal of Liability and Scientific Enquiry.
Gregory Voss of the Toulouse Business School (TBS), at Toulouse University, in France, suggests that the rise of drones for surveillance and other applications highlights particular challenges to civil liberties and tensions between these and national security and justice concerns.
The dictionary defines a "drone" as: "an unmanned aircraft or ship guided by remote control." Drones may use global positioning system (GPS) satellite technology, advanced , high-resolution camera technology and embedded computer systems and so have many advantages over all previously existing surveillance methods. "The fact that they may be operated without personnel onboard allows them to be used when conventional aerial surveillance is too costly, or for long periods of time where personnel fatigue is an issue," explains Voss. These unmanned flying machines can also be much smaller than conventional aircraft and so less expensive and less obtrusive. Voss points out that the drones currently deployed in active military zones may soon need to be put to new use on their return to the USA and elsewhere once active military service is complete. He also adds that the domestic use of drones is very likely to be spurred on by industry.
"The use of images and other data from drones for security purposes has not yet been the subject of specific legal provisions. However, existing legal principles must be complied with in order to allow this use," says Voss. European Union law has provision only for the data once it has been obtained not regarding how it is obtained. US law focuses on government intrusion but there are also constitutional guarantees regarding how data is obtained, leaving this up to member state law, and whether it is admissible as evidence in a criminal court. However, in the aftermath of the National Security Agency (NSA) "PRISM" revelations and subsequent scandal, the emergence of drones and their privacy implications may give new impetus to the adoption of privacy legislation at the Federal level in the USA.
Story Source:
The above story is based on materials provided by Inderscience. Note: Materials may be edited for content and length.
Journal Reference:
- W. Gregory Voss. Privacy law implications of the use of drones for security and justice purposes. International Journal of Liability and Scientific Enquiry, 2013; 6 (4): 171 DOI: 10.1504/IJLSE.2013.060848
A new way to harness waste heat: Electrochemical approach has potential to efficiently turn low-grade heat to electricity
Scientists have found a new alternative for low-temperature waste-heat conversion into electricity.
Vast amounts of excess heat are generated by industrial processes and by electric power plants; researchers around the world have spent decades seeking ways to harness some of this wasted energy. Most such efforts have focused on thermoelectric devices, solid-state materials that can produce electricity from a temperature gradient, but the efficiency of such devices is limited by the availability of materials.
Now researchers at MIT and Stanford University have found a new alternative for low-temperature waste-heat conversion into electricity -- that is, in cases where temperature differences are less than 100 degrees Celsius.
The new approach, based on a phenomenon called the thermogalvanic effect, is described in a paper published in the journal Nature Communications by postdoc Yuan Yang and professor Gang Chen at MIT, postdoc Seok Woo Lee and professor Yi Cui at Stanford, and three others.
Since the voltage of rechargeable batteries depends on temperature, the new system combines the charging-discharging cycles of these batteries with heating and cooling, so that the discharge voltage is higher than charge voltage. The system can efficiently harness even relatively small temperature differences, such as a 50 degrees Celsius difference.
To begin, the uncharged battery is heated by the waste heat. Then, while at the higher temperature, the battery is charged; once fully charged, it is allowed to cool. Because the charging voltage is lower at high temperatures than at low temperatures, once it has cooled the battery can actually deliver more electricity than what was used to charge it. That extra energy, of course, doesn't just appear from nowhere: It comes from the heat that was added to the system.
The system aims at harvesting heat of less than 100 degrees Celsius, which accounts for a large proportion of potentially harvestable waste heat. In a demonstration with waste heat of 60 degrees Celsius the new system has an estimated efficiency of 5.7 percent.
The basic concept for this approach was initially proposed in the 1950s, Chen says, but "a key advance is using material that was not around at that time" for the battery electrodes, as well as advances in engineering the system.
That earlier work was based on temperatures of 500 degrees Celsius or more, Yang adds; most current heat-recovery systems work best with higher temperature differences.
While the new system has a significant advantage in energy-conversion efficiency, for now it has a much lower power density -- the amount of power that can be delivered for a given weight -- than thermoelectrics. It also will require further research to assure reliability over a long period of use, and to improve the speed of battery charging and discharging, Chen says. "It will require a lot of work to take the next step," he cautions.
Chen, the Carl Richard Soderberg Professor of Power Engineering and head of MIT's Department of Mechanical Engineering, says there's currently no good technology that can make effective use of the relatively low-temperature differences this system can harness. "This has an efficiency we think is quite attractive," he says. "There is so much of this low-temperature waste heat, if a technology can be created and deployed to use it."
Cui says, "Virtually all power plants and manufacturing processes, like steelmaking and refining, release tremendous amounts of low-grade heat to ambient temperatures. Our new battery technology is designed to take advantage of this temperature gradient at the industrial scale."
Lee adds, "This technology has the additional advantage of using low-cost, abundant materials and manufacturing process that are already widely used in the battery industry."
Peidong Yang, a professor of chemistry at the University of California at Berkeley who was not involved in this work, says, "By exploring the thermogalvanic effect, [the MIT and Stanford researchers] were able to convert low-grade heat to electricity with decent efficiency. It is a very promising technology. … This is a clever idea, and low-grade waste heat is everywhere."
MIT's Yang underscores that point: "One-third of all energy consumption in the United States ends up as low-grade heat."
The MIT work was partially funded by the U.S. Department of Energy, in part through the Solid-State Solar-Thermal Energy Conversion Center, and the U.S. Air Force. The work at Stanford was partially funded by the DOE, the SLAC National Accelerator Laboratory, and National Research Foundation of Korea.
Story Source:
The above story is based on materials provided by Massachusetts Institute of Technology. The original article was written by David L. Chandler. Note: Materials may be edited for content and length.
Journal Reference:
- Seok Woo Lee, Yuan Yang, Hyun-Wook Lee, Hadi Ghasemi, Daniel Kraemer, Gang Chen, Yi Cui. An electrochemical system for efficiently harvesting low-grade heat energy. Nature Communications, 2014; 5 DOI: 10.1038/ncomms4942
Weak chemical forces combined to strengthen novel imaging technology
May 21/ 2014
Institute for Genomic Biology, University of Illinois at Urbana-Champaign
Increasing the effectiveness of certain contrast agents is often used for imaging blood vessels and internal bleeding by associating them with nanoparticles, biomedical researchers report. The contrast agent being used is packaged inside or bonded to the surface of microscopic particles, which can be designed to target certain regions of the body or prolong the agent's activity.
Kong and others demonstrated that their fastener molecule readily inserted itself into the membrane of pre-made liposomes. Gadolinium stably associated with the modified nanoparticles in solution, and experiments in animal models showed that these nanoparticles produced clear diagnostic images.
When Associate Professor of Chemical and Biomolecular Engineering Hyunjoon Kong, graduate student Cartney Smith, and colleagues set out to improve MR imaging (MRI), they turned current contrast agent technology on its head -- or rather, they turned it inside out. The new compound they designed in collaboration with Roger Adams Professor of Chemistry Steven C. Zimmerman is not only more effective, but also self-assembling. Kong is a member of the Regenerative Biology and Tissue Engineering research theme at the Institute for Genomic Biology.
When doctors perform an MRI, they administer a contrast agent: a chemical that, when injected into the bloodstream or ingested by the patient just before the MRI, improves the clarity of structures or organs in the resulting image. One common class of contrast agent, often used for imaging of blood vessels and internal bleeding, contains gadolinium, a rare-earth metal.
Recently, biomedical researchers have found ways to increase the effectiveness of certain contrast agents by associating them with nanoparticles. The contrast agent being used is packaged inside or bonded to the surface of microscopic particles, which can be designed to target certain regions of the body or prolong the agent's activity.
Researchers are now exploring the multipurpose use of nanoparticles. If particles could be loaded with several types of contrast agents or dyes instead of one, or a contrast agent along with another type of diagnostic aid or a medication, doctors could more efficiently test for and treat conditions, and limit the number of injections received by patients.
Just like toddlers sharing a new toy, though, compounds packaged together into a nanoparticle cannot always play well together. For example, contrast agents may bind to other chemicals, reducing their effectiveness. In addition, when contrast agents are enclosed inside a nanoparticle, they may not work as well. Attempts to attach agents to the outer surface of nanoparticles via covalent formation are also problematic, as they can negatively affect the activity of the nanoparticles or the compounds that they carry.
Kong, Smith and colleagues tackled these challenges by using interactions between naturally occurring biomolecules as a guide. Many types of proteins are strongly attached to cell membranes not by covalent bonds, but by the sum of multiple weaker forces -- the attraction of positive and negative charges, and the tendency of non-polar (oil-like) substances to seek each other and avoid water.
The group hypothesized that the same types of forces could be used to attach a contrast agent to the surface of a type of nanoparticle called a liposome, which resembles a little piece of cell membrane in the shape of a tiny bubble. The researchers designed a "fastener" molecule, DTPA-chitosan-g-C18, that is charged, attracting it to the liposome and binding it to the contrast agent gadolinium. A nonpolar region anchors it to the liposome membrane.
In a series of experiments reported in a recent ACS Nano article, Kong and others demonstrated that their fastener molecule readily inserted itself into the membrane of pre-made liposomes. Gadolinium stably associated with the modified nanoparticles in solution, and experiments in animal models showed that these nanoparticles produced clear diagnostic images.
"The strategy works like Velcro on a molecular level to adhere functional units to the outer leaflet of a liposome," said Smith, who was first author on the study. "This work represents a new material design strategy that is scalable and easily implemented. The development of improved contrast agents has the potential to directly impact patients' lives by detecting damaged blood vessels."
One of the difficulties of working with liposomes is their tendency to degrade inside the body. When the fastener-loaded liposomes degraded, some of the efficacy of the gadolinium was lost. In a second study published in Langmuir (DOI: 10.1021/la500412r), Kong and Smith developed a process for chemically cross-linking the components of the nanoparticle that prolonged the life of the nanoparticles in biological conditions.
Story Source:
The above story is based on materials provided by Institute for Genomic Biology, University of Illinois at Urbana-Champaign. The original article was written by Claudia Lutz. Note: Materials may be edited for content and length.
Journal Reference:
- Cartney E. Smith, Hyunjoon Kong. Cross-Linkable Liposomes Stabilize a Magnetic Resonance Contrast-Enhancing Polymeric Fastener. Langmuir, 2014; 30 (13): 3697 DOI: 10.1021/la500412r
New, fossil-fuel-free process makes biodiesel sustainable
MSU is working to eliminate biodiesel producers' hazardous wastes and dependence on fossil fuels.
A new fuel-cell concept, developed by an Michigan State University researcher, will allow biodiesel plants to eliminate the creation of hazardous wastes while removing their dependence on fossil fuel from their production process.
The platform, which uses microbes to glean ethanol from glycerol and has the added benefit of cleaning up the wastewater, will allow producers to reincorporate the ethanol and the water into the fuel-making process, said Gemma Reguera, MSU microbiologist and one of the co-authors.
"With a saturated glycerol market, traditional approaches see producers pay hefty fees to have toxic wastewater hauled off to treatment plants," she said. "By cleaning the water with microbes on-site, we've come up with a way to allow producers to generate bioethanol, which replaces petrochemical methanol. At the same time, they are taking care of their hazardous waste problem."
The results, which appear in the journal Environmental Science and Technology, show that the key to Reguera's platform is her patented adaptive-engineered bacteria -- Geobacter sulfurreducens.
Geobacter are naturally occurring microbes that have proved promising in cleaning up nuclear waste as well in improving other biofuel processes. Much of Reguera's research with these bacteria focuses on engineering their conductive pili or nanowires. These hair-like appendages are the managers of electrical activity during a cleanup and biofuel production.
First, Reguera, along with lead authors and MSU graduate students Allison Speers and Jenna Young, evolved Geobacter to withstand increasing amounts of toxic glycerol. The next step, the team searched for partner bacteria that could ferment it into ethanol while generating byproducts that 'fed' the Geobacter.
"It took some tweaking, but we eventually developed a robust bacterium to pair with Geobacter," Reguera said. "We matched them up like dance partners, modifying each of them to work seamlessly together and eliminate all of the waste."
Together, the bacteria's appetite for the toxic byproducts is inexhaustible.
"They feast like they're at a Las Vegas buffet," she added. "One bacterium ferments the glycerol waste to produce bioethanol, which can be reused to make biodiesel from oil feedstocks. Geobacter removes any waste produced during glycerol fermentation to generate electricity. It is a win-win situation."
The hungry microbes are the featured component of Reguera's microbial electrolysis cells, or MECs. These fuel cells do not harvest electricity as an output. Rather, they use a small electrical input platform to generate hydrogen and increase the MEC's efficiency even more.
The promising process already has caught the eye of economic developers, who are helping scale up the effort. Through a Michigan Translational Research and Commercialization grant, Reguera and her team are developing prototypes that can handle larger volumes of waste.
Reguera also is in talks with MBI, the bio-based technology "de-risking" enterprise operated by the MSU Foundation, to develop industrial-sized units that could handle the capacities of a full-scale biodiesel plant. The next step will be field tests with a Michigan-based biodiesel manufacturer.
Story Source:
The above story is based on materials provided by Michigan State University. Note: Materials may be edited for content and length.
Coffee bean roasting acoustics
Coffee beans roasted into second crack.
People around the world are drawn to coffee's powerful allure -- for its beloved smell, and taste, and for the caffeine boost it provides. As you enjoy your coffee beverage, however, odds are good you're probably not thinking about the coffee bean roasting process behind it.
But for some the love of coffee runs so deep that they go so far as to roast their own coffee beans. Controlling the roast time and temperature profile allows them to dial in the range of roast levels from light to dark, which greatly affects the style, flavor, and aroma of the resulting beverage.
This drove Preston S. Wilson, a coffee aficionado and acoustician who normally focuses on studying underwater acoustics in his role as an associate professor in The University of Texas at Austin's Cockrell School of Engineering, to explore the potential of using the "cracking" sounds emitted by coffee beans during the roasting process -- as the basis for an automated acoustical roast monitoring technique.
These coffee roasting sounds are well known within the coffee roasting realm, but this is believed to be the first quantitative assessment of these sounds and the first suggestion to use them in an automated control process.
As Wilson reports in the Journal of the Acoustical Society of America -- Express Letters, he found three parameters of the crack sound that could be exploited. Near the end of the roasting process, sounds known as "first crack" exhibit higher acoustic amplitudes than the "second crack" sounds that are emitted later. Finally, the rate of cracks in the second crack chorus is higher than the rate in the first crack chorus.
"The sound of the first crack is similar to popcorn popping, while the second crack is more akin to the sound of the breakfast cereal Rice Krispies," explains Wilson.
Initially, Wilson's unfunded project was just to "satisfy his own interest as a person who roasts coffee," but a commercial application may emerge for the coffee roasting industry.
An automated acoustical roast monitoring technique "could lead to optimized coffee roasting, which would increase quality, decrease errors in roasting, and potentially save energy used to power the roasting process," he says.
Taking it to the next level and commercializing the process will "require quite a bit of effort -- engineering the design of the sensor system, the data acquisition and processing," Wilson adds. "It will require writing software to automatically process the sounds, and then integrating it into the control system."
Story Source:
The above story is based on materials provided by American Institute of Physics (AIP). Note: Materials may be edited for content and length.
Journal Reference:
- Preston S. Wilson. Coffee roasting acoustics. The Journal of the Acoustical Society of America, 2014; 135 (6): EL265 DOI: 10.1121/1.4874355
Circuits and sensors direct from the printer
Cylinder featuring functional surfaces acting as sensors.
Printers are becoming more and more versatile. Now they can even print sensors and electronic components on 2D and 3D substrates. A new, robot-assisted production line allows the process to be automated.
These days, no office is complete without a printer. But digital printing technologies also play an important role in microelectronics, microsystems engineering and sensor systems. Researchers at the Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM in Bremen use various printing methods to produce electronic components and sensors. The tiny resistors, transistors, circuit paths and capacitors are first designed on screen and then deposited directly onto two- and three-dimensional substrates, for instance circuit boards. Instead of the usual paper inks, the scientists use what are known as "functional inks" -- electronic materials in liquid or paste form. The range of potential uses for printed electronics is wide -- from the electronic circuits in digital thermometers to flexible sheets of solar cells and smart packaging with built-in sensors.
To automate the process of applying printed electronics to components with flat and three-dimensional surfaces, the IFAM scientists have set up a robot-assisted production line that allows different printing methods to be combined in a single run. Modules for silk-screen, inkjet, dispenser, and aerosol-jet printing are integrated in the production unit. "The production line with its central robotic unit, component feeders, printing systems and heat treatment furnaces enables us to functionalize surfaces on a near-industrial scale," says Dr. Volker Zöllmer, head of the Functional Structures department at IFAM.
The availability of different technologies in one system makes it possible to print structures of different surface areas, widths, and thicknesses on the substrate. Aerosol-jet printing, for instance, enables the researchers to deposit extremely fine structures with a width of only 10 micrometers onto the component. In this non-contact process, the conductive ink is transformed into an aerosol using compressed air (pneumatic spraying), and then fed to the print head through a fine tube. The print head focuses the aerosol jet on the surface of the substrate, which doesn't necessarily have to be flat or smooth -- even curved surfaces can be printed on using this method. It is also possible to vary the thickness of the printed features and create multilayer structures. "For example, as well as laying down circuits on a circuit board, we can also provide it with a corrosion-resistant coating," says Zöllmer.
So how exactly does this printing process work? After the control software has been programmed for the desired end product, by defining the printing methods required and the order in which they are to be executed, the robot picks up the substrate, for instance a bare circuit board, and dispatches it to the first printing station. If the task requires integrating 200-micrometer-wide circuit paths in the substrate, it is first sent to the dispenser, a piezoelectric dosing system. The dispenser contains a valve that allows the precise volume and droplet size of the viscous medium -- e.g. an electrically conductive adhesive -- to be applied. If the conductor is to be connected to a sensor, the circuit board is then routed to the aerosol-jet printer. This high-resolution device prints the sensors. The circuit board then passes through other printers, depending on the application, before finally undergoing heat treatment in the furnace, in order to obtain the desired performance characteristics. The system is capable of printing on substrates up to the size of a DIN-A3 sheet of paper, and can process components with a height of several centimeters.
Functionalized surfaces to order
The choice of materials that can be used as substrates or functional inks is almost unlimited. The inks employed by the IFAM specialists include metals, ceramics, electrically conductive polymers, and even biomaterials such as proteins and enzymes. Depending on the application, these media are deposited on substrates made of glass, textiles, metals, ceramic plates, and many other materials. "The new production line enables us to process a wide range of different materials and combine them in many different ways to meet the customer's requirements. This includes designing components capable of providing entirely new functions -- such as window panes with integrated sensors for measuring temperature." Zöllmer adds. "Printed sensors can also be used to monitor building components, providing early warning of crack formation and other structural damage. They could also be useful in the car industry, where strain gages printed on aluminum surfaces by means of aerosol-jet printing could provide an early indication of material fatigue in body components."
The robot-assisted production line also helps to shorten development lead times. In the past, to provide components with sensor functions, it was often necessary to integrate the sensors in the component after it had been manufactured -- a time-consuming process. Depending on the application, the IFAM researchers can achieve the same result in a matter of seconds or minutes by printing fully functionalized components. This offers advantages to many sectors of industry, including car manufacturing and aerospace, and also microsystems engineering. "We can help industry to streamline its product development processes, by manufacturing prototypes and small batches using our production line," says Zöllmer. The modular production line also provides scope for customers to add their own processes.
New target for chronic pain treatment found
May 21/ 2014
University of North Carolina Health Care
The enzyme PIP5K1C controls the activity of cellular receptors that signal pain, researchers have found. By reducing the enzyme, researchers showed that levels of a lipid called PIP2 is also lessened. They also found a compound that can dampen the activity of PIP5K1C. These findings could lead to a new kind of pain reliever for the more than 100 million people who suffer from chronic pain in the US.
Pain is signaled from the place of injury to the dorsal root ganglia – clusters of neurons alongside the spinal cord – before the pain is signaled into the spinal cord and finally the brain. Mark Zylka, PhD, has found a way to lessen the signal – and thus pain – at the dorsal root ganglia.
Researchers at the UNC School of Medicine have found a new target for treating chronic pain: an enzyme called PIP5K1C. In a paper published today in the journal Neuron, a team of researchers led by Mark Zylka, PhD, Associate Professor of Cell Biology and Physiology, shows that PIP5K1C controls the activity of cellular receptors that signal pain.
By reducing the level of the enzyme, researchers showed that the levels of a crucial lipid called PIP2 in pain-sensing neurons is also lessened, thus decreasing pain.
They also found a compound that could dampen the activity of PIP5K1C. This compound, currently named UNC3230, could lead to a new kind of pain reliever for the more than 100 million people who suffer from chronic pain in the United States alone.
In particular, the researchers showed that the compound might be able to significantly reduce inflammatory pain, such as arthritis, as well as neuropathic pain -- damage to nerve fibers. The latter is common in conditions such as shingles, back pain, or when bodily extremities become numb due to side effects of chemotherapy or diseases such as diabetes.
The creation of such bodily pain might seem simple, but at the cellular level it's quite complex. When we're injured, a diverse mixture of chemicals is released, and these chemicals cause pain by acting on an equally diverse group of receptors on the surface of pain-sensing neurons.
"A big problem in our field is that it is impractical to block each of these receptors with a mixture of drugs," said Zylka, the senior author of the Neuron article and member of the UNC Neuroscience Center. "So we looked for commonalities -- things that each of these receptors need in order to send a signal." Zylka's team found that the lipid PIP2 (phosphatidylinositol 4,5-bisphosphate) was one of these commonalities.
"So the question became: how do we alter PIP2 levels in the neurons that sense pain?" Zylka said. "If we could lower the level of PIP2, we could get these receptors to signal less effectively. Then, in theory, we could reduce pain."
Many different kinases can generate PIP2 in the body. Brittany Wright, a graduate student in Zylka's lab, found that the PIP5K1C kinase was expressed at the highest level in sensory neurons compared to other related kinases. Then the researchers used a mouse model to show that PIP5K1C was responsible for generating at least half of all PIP2 in these neurons.
"That told us that a 50 percent reduction in the levels of PIP5K1C was sufficient to reduce PIP2 levels in the tissue we were interested in -- where pain-sensing neurons are located" Zylka said. "That's what we wanted to do -- block signaling at this first relay in the pain pathway."
Once Zylka and colleagues realized that they could reduce PIP2 in sensory neurons by targeting PIP5K1C, they teamed up with Stephen Frye, PhD, the Director of the Center for Integrative Chemical Biology and Drug Discovery at the UNC Eshelman School of Pharmacy.
They screened about 5,000 small molecules to identify compounds that might block PIP5K1C. There were a number of hits, but UNC3230 was the strongest. It turned out that Zylka, Frye, and their team members had come upon a drug candidate. They realized that the chemical structure of UNC3230 could be manipulated to potentially turn it into an even better inhibitor of PIP5K1C. Experiments to do so are now underway at UNC.
Story Source:
The above story is based on materials provided by University of North Carolina Health Care. Note: Materials may be edited for content and length.
Journal Reference:
- Brittany D. Wright, Lipin Loo, Sarah E. Street, Anqi Ma, Bonnie Taylor-Blake, Michael A. Stashko, Jian Jin, William P. Janzen, Stephen V. Frye, Mark J. Zylka. The Lipid Kinase PIP5K1C Regulates Pain Signaling and Sensitization. Neuron, 2014; 82 (4): 836 DOI: 10.1016/j.neuron.2014.04.006
Shared custody is becoming the norm in the United States of America
It's no longer a certainty that mothers living in the United States will get custody over their children during a divorce. In fact, if Wisconsin Court Records of the past 20 years are anything to go by, joint custody is becoming the norm. So says Maria Cancian and colleagues from the University of Wisconsin-Madison in the US, whose findings are published in Springer's journal Demography.
For most of the twentieth century, in both divorce and nonmarital cases, most children ended up living with their mothers after their parents' divorce. This conformed to gender norms that views mothers as better caretakers of especially young children. However, the guiding principle of the "best interest of the child" has since become standard in deciding on custody matters.
Since the turn of the millennium, the custody policy of some states has become gender-neutral and encourages the involvement of both parents.
In 1998, Cancian and her colleague Daniel Meyer published the first results showing a drop in the proportion of mothers granted sole custody, from 80 percent in 1986 to 74 percent in 1994. Shared custody cases rose from 7 percent to 14 percent. The analysis was based on all Wisconsin Court Records involving minor children in divorce cases between 1986 and 1994.
To extend this study further, Cancian and colleagues have now included relevant Wisconsin Court Records until 2008, comprising 9,873 divorce cases in total. It shows sustained changes in mother-sole custody cases over the past 20 years: down from 80 percent in 1986 to 42 percent in 2008. This decline is largely mirrored by a dramatic increase in shared custody. Equal shared custody, in which children spend an equal number of nights with both parents, increased from 5 percent to 27 percent, while unequal shared custody increased from 3 percent to 18 percent.
The researchers believe that a significant milestone has been reached in the last decade, with more divorce judgments being handed down without mother-sole custody than with it. In contrast, there has been little change in the share of father sole-custody cases: 11 percent in 1988 against 9 percent in 2008.
The analysis further shows that shared custody remains more likely for higher income families, while the gender and age of the children involved do not carry much weight.
The authors believe that custody patterns are changing because of transforming social norms and the new processes by which custody is determined. Their findings could have important implications for the structuring of social policy, such as tax and transfer programs in the US. "Overall, the trend away from mother-sole custody and toward shared custody is dramatic, representing a substantial change in the living situations of children of divorce over a relatively short period," says Cancian.
Story Source:
The above story is based on materials provided by Springer. Note: Materials may be edited for content and length.
Journal Reference:
- Maria Cancian, Daniel R. Meyer, Patricia R. Brown, Steven T. Cook. Who Gets Custody Now? Dramatic Changes in Children’s Living Arrangements After Divorce. Demography, 2014; DOI: 10.1007/s13524-014-0307-8
Breakthrough: Nasal spray may soon replace pills for delivering drugs to the brain
When a patient sprays a solution with active drugs into his nose cavity, the solution will hit the nasal wall and wander from here through the nasal wall to the relevant places in the brain.
When the doctor gives us medicine, it is often in the shape of a pill. But when it comes to brain diseases, pills are actually an extremely inefficient way to deliver drugs to the brain, and according to researchers from University of Southern Denmark we need to find new and more efficient ways of transporting drugs to the brain. Spraying the patient's nose could be one such way.
Every time we have an infection or a headache and take a pill, we get a lot more drugs than our body actually needs. The reason is that only a fraction of the drugs in a pill reaches the right places in the body; the rest never reaches its destination and may cause unwelcome side effects before they are flushed out of the body again. This kind of major overdosing is especially true when doctors treat brain diseases, because the brain does not easily accept entering drugs.
"People with brain diseases are often given huge amounts of unnecessary drugs. During a long life, or if you have a chronic disease, this may become problematic for your health," says Massimiliano Di Cagno, assistant professor at the Department of Physics, Chemistry and Pharmacy, University of Southern Denmark.
He is concerned with finding more efficient ways of delivering drugs to the brain. He and his colleagues at University of Southern Denmark and Aalborg University have turned their attention to the nose -- specifically the nasal wall and the slimy mucosa that covers it.
As we know from e.g. cocaine addicts, substances can be assimilated extremely quickly and directly through the nose. But many medical substances, however, need help to be transported through the nasal wall and further on to the relevant places in the brain.
Researchers have long struggled with this challenge and have come up with different kinds of transport vehicles that are very good at transporting the active ingredients through the nasal wall into the brain. The problem with these vehicles, though, is that they cannot release their cargo of drugs once they have reached the inside of the brain. The drugs stay locked inside the strong vehicles.
"If the drugs cannot get out of their vehicles, they are no help to the patient. So we needed to develop a vehicle that does not lock the drug in," explains Massimiliano Di Cagno.
The vehicles for drug delivery through the nose are typically made of so called polymers. A polymer is a large molecule composed of a large number of repeats of one or more types of atoms or groups of atoms bound to each other. Polymers can be natural or synthetic, simple or complex.
Direct track to the brain
Massimiliano Di Cagno and his colleagues tested a natural sugar polymer and they now report that this particular polymer is not only capable of carrying the drugs through the nasal wall but also -- and most importantly -- releasing the drug where it is needed.
"This is an important breakthrough, which will bring us closer to delivering brain drugs by nasal spray," says Massimiliano Di Cagno.
With this discovery two out of three major challenges in nasal delivery of brain drugs have been met:
"We have solved the problem of getting the drug through the nose, and we have solved the problem of getting the drug released once it has entered the brain. Now there is a third major challenge left: To secure a steady supply of drugs over a long period. This is especially important if you are a chronic patient and need drug delivery every hour or so," says Massimiliano Di Cagno.
When a patient sprays a solution with active drugs into his nose cavity, the solution will hit the nasal wall and wander from here through the nasal wall to the relevant places in the brain.
"But gravity also rules inside the nose cavity and therefore the spray solution will start to run down as soon as it has been sprayed up the nose. We need it to cling to the nasal wall for a long time, so we need to invent some kind of glue that will help the solution stick to the nasal wall and not run down and out of the nose within minutes," says Massimiliano Di Cagno.
Story Source:
The above story is based on materials provided by University of Southern Denmark. Note: Materials may be edited for content and length.
Journal Reference:
- Massimiliano di Cagno, Thorbjørn Terndrup Nielsen, Kim Lambertsen Larsen, Judith Kuntsche, Annette Bauer-Brandl. β-Cyclodextrin-dextran polymers for the solubilization of poorly soluble drugs. International Journal of Pharmaceutics, 2014; 468 (1-2): 258 DOI: 10.1016/j.ijpharm.2014.04.029
Disruption of circadian rhythms may contribute to inflammatory disease
May 21, 2014
Rush University Medical Center
A disruption of circadian rhythms, when combined with a high-fat, high-sugar diet, may contribute to inflammatory bowel disease and other harmful conditions, according to a recent study. "Circadian rhythms, which impose a 24-hour cycle on our bodies, are different from sleep patterns," the first author of the study explained. "Sleep is a consequence of circadian rhythms." While circadian rhythm disruption may be common among some, the research suggests that it may be contributing to a host of diseases.
A disruption of circadian rhythms, when combined with a high-fat, high-sugar diet, may contribute to inflammatory bowel disease and other harmful conditions, according to a recent study conducted by researchers at Rush University Medical Center. The study is online at the peer-reviewed, open-access journal, PLOS ONE.
"Circadian rhythms, which impose a 24-hour cycle on our bodies, are different from sleep patterns," said Robin M. Voigt, PhD, assistant professor at Rush Medical College and first author of the study. "Sleep is a consequence of circadian rhythms," Voigt said.
While circadian rhythm disruption may be common among some, the research suggests that it may be contributing to a host of diseases that may be prevented by regulating things such as sleep/wake patterns and times of eating to help prevent circadian rhythm disruption. Including prebiotics or probiotics in the diet can also help normalize the effects of circadian rhythm disruption on the intestinal microbiota to reduce the presence of inflammation.
"It's something that needs to be addressed -- not something people need to be very concerned about, but aware. If you have some of these other risk factors, like a high-fat, high-sugar diet," or a genetic tendency toward disruption in circadian rhythms, "take precautions, watch your diet, take pre- and probiotics, monitor your health, be vigilant," Voigt said.
The prevailing theory is that of a "second hit hypothesis" whereby individuals with at-risk lifestyle choices or genetic predispositions will only develop disease if a secondary insult is present. "We believe that chronic circadian rhythm disruption promotes/exacerbates inflammatory-mediated diseases, at least in part, due to changes in the intestinal microbiota," she said.
Inflammation is associated with a number of diseases, including cardiovascular disease and cancer, and can cause organ damage and is associated with increased morbidity and mortality.
In the study, male mice had their cycles of exposure to light and dark reversed on a weekly basis (i.e., "shifted"), an experience that is known to disrupt an organism's innate circadian rhythm. Some of the mice ate standard food; others ate a high-fat, high-sugar diet. Researchers found that the microbiota of the mice that had their circadian rhythms disrupted were significantly different from that of the control group -- but only if they had consumed the high-fat, high-sugar diet.
All the mice that ate the high-fat, high-sugar diet displayed changes in the makeup of the microorganisms in their guts, regardless of circadian status. However, mice that ate the high-fat, high-sugar diet, and had circadian-rhythm disruptions, had higher concentrations of bacteria that are known to promote inflammation than any of the other mice in the study. Disrupting the circadian rhythms of the mice fed standard chow did not significantly affect the microbiota in their intestines.
These findings support previous studies that have shown that the negative effects of circadian disruption are subtle enough that "a second environmental insult is often necessary to reveal [their] deleterious effects," the study says.
Many people have their circadian rhythms disrupted on a regular basis -- shift workers like nurses, doctors, firefighters and policemen. "Other people have 'social jet lag,' a lifestyle pattern that leads them to maintain a normal schedule on weekdays, but then stay up late and sleep in on the weekends," Voigt said.
"Looking forward, we would like to functionally evaluate how circadian rhythm disruption may influence diseases including colon cancer, which may in part be the consequence of altered intestinal microbiota," she concluded.
Story Source:
The above story is based on materials provided by Rush University Medical Center. Note: Materials may be edited for content and length.
Journal Reference:
- Robin M. Voigt, Christopher B. Forsyth, Stefan J. Green, Ece Mutlu, Phillip Engen, Martha H. Vitaterna, Fred W. Turek, Ali Keshavarzian. Circadian Disorganization Alters Intestinal Microbiota. PLoS ONE, 2014; 9 (5): e97500 DOI: 10.1371/journal.pone.0097500