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1.
Biofuels are considered as a carbon neutral alternative to hydrocarbons in the transport sector and this approach has triggered concerns about the impact the production of biofuels might have on land usage. Another option that might also lead to reduced emissions in the transport sector is electricity based on renewable energy sources such as biomass. Below, we assess the benefits and drawbacks of the joint production of ethanol and electricity in a sugar cane based refinery, and the use of both energy forms in privately owned automobiles. In this analysis, we have considered technology for energy production that is currently available and cost competitive. The results show that the amount of land that is required to power our current automobile use needs is less than what is typically stated. According to our results that are based on 2010 values, 2 million ha of land are sufficient to power the Brazilian automobile fleet, 25 million ha are enough to satisfy the needs of the U.S. fleet, and 67 million ha are sufficient to cover the global autofuel requirements. When minor efficiency gains are considered, 19 million ha will be enough to satisfy the fuel needs of the U.S. fleet in 2030, whereas land required to supply the Brazilian and global fleet remain basically unchanged. Our analysis shows that the harvested energy density of sugar cane is 306 GJ/ha/yr, which is 1.7 times the value usually reported in the literature for biofuels. As a result, taking advantage of the primary energy potential of sugar cane, only 4% of the world's available cropland area would be sufficient to produce fuels that would power the global car fleet.  相似文献   

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Gut microbiomes may have a significant impact on mood and cognition, which is leading experts towards a new frontier in neuroscience. Studies have shown that increase in the amount of good bacteria in the gut can curb inflammation and cortisol level, reduces symptoms of depression and anxiety, lowers stress reactivity, improves memory and even lessens neuroticism and social anxiety. This shows that, probably the beneficial gut bacteria or probiotics function mechanistically as delivery vehicles for neuroactive compounds. Thus, a psychobiotic is a live organism, when ingested in adequate amounts, produces a health benefit in patients suffering from psychiatric illness. Study of these novel class of probiotics may open up the possibility of rearrangement of intestinal microbiota for effective management of various psychiatric disorders.  相似文献   

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A mean stress failure criterion is applied to the Volkersen-model used for analysis of lag screws and glued-in rods subjected to withdrawal. Expressions are derived for pull-pull as well as pull-push loading conditions. The solutions for glued-in rods appear as special cases of the theory for lag screws, and the usual solutions for a maximum stress failure criterion appear as special cases of the solutions for a mean stress failure criterion. The theoretical solutions for lag screws are compared with test results, and a suggestion is made for taking into account initial shear stresses caused by the thread of the screw when driving the screw into the wood. The main advantage of considering initial shear stresses is that the number of necessary fitting parameters is limited to one, and that the usual values of shear strength and mode II fracture energy of wood can be applied.  相似文献   

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Mucositis, characterized by ulcerative lesions along the alimentary tract, is a common consequence of many chemotherapy regimens. Chemotherapy negatively disrupts the intestinal microbiota, resulting in increased numbers of potentially pathogenic bacteria, such as Clostridia and Enterobacteriaceae, and decreased numbers of “beneficial” bacteria, such as Lactobacilli and Bifidobacteria. Agents capable of restoring homeostasis in the bowel microbiota could, therefore, be applicable to mucositis. Prebiotics are indigestible compounds, commonly oligosaccharides, that seek to reverse chemotherapy-induced intestinal dysbiosis through selective colonization of the intestinal microbiota by probiotic bacteria. In addition, evidence is emerging that certain prebiotics contribute to nutrient digestibility and absorption, modulate intestinal barrier function through effects on mucin expression, and also modify mucosal immune responses, possibly via inflammasome-mediated processes. This review examines the known mechanisms of prebiotic action, and explores their potential for reducing the severity of chemotherapy-induced mucositis in the intestine.  相似文献   

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The past 5 years have seen some major successes in terms of global measurement and regulation of persistent, bioaccumulative, and toxic (PB&T) chemicals and persistent organic pollutants (POPs). The Stockholm Convention, a global agreement on POPs, came into force in 2004. There has been a major expansion of measurements and risk assessments of new chemical contaminants in the global environment, particularly brominated diphenyl ethers and perfluorinated alkyl acids. However, the list of chemicals measured represents only a small fraction of the approximately 30,000 chemicals widely used in commerce (>1 t/y). The vast majority of existing and new chemical substances in commerce are not monitored in environmental media. Assessment and screening of thousands of existing chemicals in commerce in the United States, Europe, and Canada have yielded lists of potentially persistent and bioaccumulative chemicals. Here we review recent screening and categorization studies of chemicals in commerce and address the question of whether there is now sufficient information to permit a broader array of chemicals to be determined in environmental matrices. For example, Environment Canada's recent categorization of the Domestic (existing) Substances list, using a wide array of quantitative structure activity relationships for PB&T characteristics, has identified about 5.5% of 11,317 substances as meeting P & B criteria. Using data from the Environment Canada categorization, we have listed, for discussion purposes, 30 chemicals with high predicted bioconcentration and low rate of biodegradation and 28 with long range atmospheric transport potential based on predicted atmospheric oxidation half-lives >2 days and log air-water partition coefficients > or =5 and < or =1. These chemicals are a diverse group including halogenated organics, cyclic siloxanes, and substituted aromatics. Some of these chemicals and their transformation products may be candidates for future environmental monitoring. However, to improve these predictions data on emissions from end use are needed to refine environmental fate predictions, and analytical methods may need to be developed.  相似文献   

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Guo W.  Mo Y.  Huang Y.  Wang K.  Chen N. 《丝绸》2018,(9):1-6
In order to explore suitable reactive inks for silk digital printing, reactive dye inks of eight brands were selected from the domestic market to evaluate their pH, Conductivity, absorption spectrum, color gamut range and their application performance including color yield, dry and wet rubbing fastness. The results showed that pH values of ink of different brands ranged from neutral and weakly acidic property, which would be helpful to reduce hydrolysis of the reactive dye and improve their stability. Reactive inks with lower conductivity could avoid salt crystallization which would cause nozzle blocking and corrosion problem. The hue of three primary colors (CMY) was stable, while that of spot color (BRO) had some differences, and the overall gamut range of these ink sets were different at different brightness levels. The application performance of the printed silk demonstrated that the increase in the stability of reactive ink would improve the color yield and color fastness of the printed fabric. © 2018 China Silk Association. All rights reserved.  相似文献   

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The aim of this review is to describe the factors contributing to diminished food intake, resulting in nutritional deficiencies and associated health conditions in older adults and proposes food innovation strategies to mitigate these. Research has provided convincing evidence of a link between healthy eating patterns and healthy aging. There is a need to target new food product development (NPD) with functional health benefits specifically designed to address the particular food‐related needs of older consumers. When developing foods for older adults, consideration should be given to the increased requirements for specific macro‐ and micronutrients, especially protein, calcium, vitamin D, and vitamin B. Changes in chemosensory acuity, chewing difficulties, and reduced or poor swallowing ability should also be considered. To compensate for the diminished appetite and reduced intake, foods should be energy dense, nutritionally adequate, and, most importantly, palatable, when targeting this cohort. This paper describes the potential of new food product development to facilitate dietary modification and address health deficiencies in older adults.  相似文献   

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Modified atmosphere packaging (MAP) is the removal and/or replacement of the atmosphere surrounding the product before sealing in vapor-barrier materials. While technically different, many forms of MAP are also case-ready packaging, where meat is cut and packaged at a centralized location for transport to and display at a retail store. Most of the shelf life properties of meat are extended by use of MAP, but anoxic forms of MAP without carbon monoxide (CO) do not provide bloomed red meat color and MAP with oxygen (O(2)) may promote oxidation of lipids and pigments. Advances in plastic materials and equipment have propelled advances in MAP, but other technological and logistical considerations are needed for successful MAP systems for raw chilled fresh meat. Current MAP options of air-permeable overwrapped trays in master packs, low O(2) formats of shrunk film vacuum packaging (VP) or MAP with carbon dioxide (CO(2)) and nitrogen (N(2)) and their peelable barrier film derivatives, and high O(2) MAP each have advantages and disadvantages. Packaging technology innovations and ingenuity will continue to provide MAP that is consumer oriented, product enhancing, environmentally responsive, and cost effective, but continued research and development by the scientific and industry sectors will be needed.  相似文献   

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It is known that hair growth disorders and hair loss can cause personal distress and affect well‐being. Whilst clinical conditions remain a target for medical research, current research on hair follicle biology and hair growth control mechanisms also provides opportunities for a range of non‐medical and cosmetic interventions that have a modulating effect on the scalp and follicle function. Furthermore, an improvement of the hair fibre characteristics (cuticle structure, cortex size and integrity) could add to the overall positive visual effect of the hair array. Since phytochemicals are a popular choice because of their traditional appeal, this review provides a critical evaluation of the available evidence of their activity for hair benefit, excluding data obtained from animal tests, and offers recommendations on improving study validity and the robustness of data collection in pre‐clinical and clinical studies.  相似文献   

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Physiological consequences resulting from protein-bound Maillard compounds in foods must be discussed carefully. This was the idea behind the debate, which is put for discussion by the papers by Sebekova and Somoza, who argued for the motion that dietary advanced glycation end products (AGEs) are a health risk, and by Ames, who provided evidence against the motion. In this two excellent reviews, numerous arguments based on papers published in high-impact journals are given for each of the opinions. The fact that no final conclusion can be drawn, may reflect the need for a more comprehensive examination of this issue in the future. For a deeper understanding of biological consequences resulting from heated foods, the relationships between well-defined biological effects and well-characterized chemical structures must be studied. Prerequisite for this is profound chemistry--pure compounds, exact concentrations, and unambiguous analytical techniques. A real "risk assessment" is much too complex than to leave it up to one discipline alone. It must be a comprehensive and interdisciplinary approach, joining the resources of biology, medicine, and chemistry.  相似文献   

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BackgroundChicken eggs are considered to be nature's perfect food. The egg white is an excellent natural source of high quality protein, which is rich in essential amino acids. The yolk is a source of antioxidants, aromatic amino acids, carotenoids, vitamins, phospholipids and proteins, which not only provide nutritional value but also act pro-health and might prevent eg. from heart diseases. In turn eggshell supplies well absorbed by the human body minerals, of which the most important is calcium.Scope and approachIn this review the new trends in chicken egg research are showed. The egg components which are the most important for human health are described. This study shows also the methods of isolating the most important health-promoting ingredients from chicken eggs.Key Findings and Conclusion: Eggs are not only a highly nutritious food, but also a rich source of diverse bioactive components also including nutraceuticals. Therefore, the current research trends focus on the new look at the egg as a material acting as health-promoting functions. Currently carried out research also concern the development of new technologies for the production of bioactive ingredients of chicken eggs.These new trends introduce a new era in egg science and technology and the future of eggs and egg ingredients remains bright.  相似文献   

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According to the Academy of Nutrition and Dietetics' influential position statement on vegetarianism, meat and seafood can be replaced with milk, soy/legumes, and eggs without any negative effects in children. The United States Department of Agriculture endorses a similar view. The present paper argues that the Academy of Nutrition and Dietetics ignores or gives short shrift to direct and indirect evidence that vegetarianism may be associated with serious risks for brain and body development in fetuses and children. Regular supplementation with iron, zinc, and B12 will not mitigate all of these risks. Consequently, we cannot say decisively that vegetarianism or veganism is safe for children.  相似文献   

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Fresh meat is a highly perishable product due to its biological composition. Many interrelated factors influence the shelf life and freshness of meat such as holding temperature, atmospheric oxygen (O2), endogenous enzymes, moisture, light and most importantly, micro-organisms. With the increased demand for high quality, convenience, safety, fresh appearance and an extended shelf life in fresh meat products, alternative non-thermal preservation technologies such as high hydrostatic pressure, superchilling, natural biopreservatives and active packaging have been proposed and investigated. Whilst some of these technologies are efficient at inactivating the micro-organisms most commonly related to food-borne diseases, they are not effective against spores. To increase their efficacy against vegetative cells, a combination of several preservation technologies under the so-called hurdle concept has also been investigated. The objective of this review is to describe current methods and developing technologies for preserving fresh meat. The benefits of some new technologies and their industrial limitations is presented and discussed.  相似文献   

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Mineral oil hydrocarbons (MOH) can be found in detectable levels in a multitude of foodstuffs. Therefore, chemical analysis of food for MOH gains importance. Different proficiency testing (PT) rounds on mineral oil testing have been performed in different matrices: cereals and rice as well as cardboard samples were examined. The laboratories participating in the PT rounds had to follow specific requirements for examination. The sample materials used contained different concentrations of mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH). The PT results were statistically evaluated according to ISO 13528:2005 and additionally the HorRat(R) value was calculated to gain information on the comparability of the mineral oil testing. It could be shown that for the examined sample materials and under the chosen specifications for testing a comparable determination of the mineral oil content is possible within the required relative standard deviations. A useful analytical determination can be achieved with an acceptable relative standard deviation of <50% from a concentration of defined mineral oil fractions at ≥1 mg/kg in food. In the concentration range for MOH in food of between 1 mg/kg and 2 mg/kg, relative standard deviations of 20–40% were achieved. MOH concentrations of ≥ 2 mg/kg food were determined with good relative standard deviations of around 20%. Moreover, due to the results gained within this work a statement concerning the comparability for MOSH and MOAH contents below concentrations of 1 mg/kg food is possible: under the chosen conditions for examination as part of this work, mineral oil determination below 1 mg/kg food showed high variability. To gain reliable information with regard to consumer protection on the risk of mineral oil contents in this low concentration range further standardisation of the test method is indicated.  相似文献   

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