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People of skin of colour comprise the majority of the world's population and Asian subjects comprise more than half of the total population of the earth. Even so, the literature on the characteristics of the subjects with skin of colour is limited. Several groups over the past decades have attempted to decipher the underlying differences in skin structure and function in different ethnic skin types. However, most of these studies have been of small scale and in some studies interindividual differences in skin quality overwhelm any racial differences. There has been a recent call for more studies to address genetic together with phenotypic differences among different racial groups and in this respect several large-scale studies have been conducted recently. The most obvious ethnic skin difference relates to skin colour which is dominated by the presence of melanin. The photoprotection derived from this polymer influences the rate of the skin aging changes between the different racial groups. However, all racial groups are eventually subjected to the photoaging process. Generally Caucasians have an earlier onset and greater skin wrinkling and sagging signs than other skin types and in general increased pigmentary problems are seen in skin of colour although one large study reported that East Asians living in the U.S.A. had the least pigment spots. Induction of a hyperpigmentary response is thought to be through signaling by the protease-activated receptor-2 which together with its activating protease is increased in the epidermis of subjects with skin of colour. Changes in skin biophysical properties with age demonstrate that the more darkly pigmented subjects retaining younger skin properties compared with the more lightly pigmented groups. However, despite having a more compact stratum corneum (SC) there are conflicting reports on barrier function in these subjects. Nevertheless, upon a chemical or mechanical challenge the SC barrier function is reported to be stronger in subjects with darker skin despite having the reported lowest ceramide levels. One has to remember that barrier function relates to the total architecture of the SC and not just its lipid levels. Asian skin is reported to possess a similar basal transepidermal water loss (TEWL) to Caucasian skin and similar ceramide levels but upon mechanical challenge it has the weakest barrier function. Differences in intercellular cohesion are obviously apparent. In contrast reduced SC natural moisturizing factor levels have been reported compared with Caucasian and African American skin. These differences will contribute to differences in desquamation but few data are available. One recent study has shown reduced epidermal Cathepsin L2 levels in darker skin types which if also occurs in the SC could contribute to the known skin ashing problems these subjects experience. In very general terms as the desquamatory enzymes are extruded with the lamellar granules subjects with lowered SC lipid levels are expected to have lowered desquamatory enzyme levels. Increased pores size, sebum secretion and skin surface microflora occur in Negroid subjects. Equally increased mast cell granule size occurs in these subjects. The frequency of skin sensitivity is quite similar across different racial groups but the stimuli for its induction shows subtle differences. Nevertheless, several studies indicate that Asian skin maybe more sensitive to exogenous chemicals probably due to a thinner SC and higher eccrine gland density. In conclusion, we know more of the biophysical and somatosensory characteristics of ethnic skin types but clearly, there is still more to learn and especially about the inherent underlying biological differences in ethnic skin types.  相似文献   

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The formulation of an antioxidant/atherosclerosis hypothesis stimulated experimental and epidemiological studies on the possible role of micronutrients, including olive oil phenolics, in the protection from cardiovascular disease observed in the Mediterranean area. This article prospectively summarises our current knowledge of olive phenolics, underscore our gaps in information, and brings forward areas that are, as yet, to be explored.  相似文献   

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Mycotoxins are metabolites produced by molds that contaminate food commodities, are harmful to both humans and animals, as well as cause economic losses. Many countries have set regulatory limits and strict thresholds to control the level of mycotoxins in food and feedstuffs. New technologies and strategies have been developed to inhibit toxigenic fungal invasion and to decontaminate mycotoxins. However, many of these strategies do not sufficiently detoxify mycotoxins and leave residual toxic by-products. This review focuses on the use of phenolic compounds obtained from botanical extracts as promising bioagents to inhibit fungal growth and/or to limit mycotoxin yields. The mechanism of these botanicals, legislation concerning their use, and their safety are also discussed. In addition, recent strategies to overcome stability and solubility constraints of phenolic compounds to be used in food and feed stuffs are also mentioned.  相似文献   

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The U.S. agricultural infrastructure is one of the most productive and efficient food-producing systems in the world. Many of the characteristics that contribute to its high productivity and efficiency also make this infrastructure extremely vulnerable to a terrorist attack by a biological weapon. Several experts have repeatedly stated that taking advantage of these vulnerabilities would not require a significant undertaking and that the nation's agricultural infrastructure remains highly vulnerable. As a result of continuing criticism, many initiatives at all levels of government and within the private sector have been undertaken to improve our ability to detect and respond to an agroterrorist attack. However, outbreaks, such as the 1999 West Nile outbreak, the 2001 anthrax attacks, the 2003 monkeypox outbreak, and the 2004 Escherichia coli O157:H7 outbreak, have demonstrated the need for improvements in the areas of communication, emergency response and surveillance efforts, and education for all levels of government, the agricultural community, and the private sector. We recommend establishing an interdisciplinary advisory group that consists of experts from public health, human health, and animal health communities to prioritize improvement efforts in these areas. The primary objective of this group would include establishing communication, surveillance, and education benchmarks to determine current weaknesses in preparedness and activities designed to mitigate weaknesses. We also recommend broader utilization of current food and agricultural preparedness guidelines, such as those developed by the U.S. Department of Agriculture and the U.S. Food and Drug Administration.  相似文献   

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A wide variety of non-cigarette forms of tobacco and nicotine exist, and their use varies regionally and globally. Smoked forms of tobacco such as cigars, bidis, kreteks and waterpipes have high popularity and are often perceived erroneously as less hazardous than cigarettes, when in fact their health burden is similar. Smokeless tobacco products vary widely around the world in form and the health hazards they present, with some clearly toxic forms (eg, in South Asia) and some forms with far fewer hazards (eg, in Sweden). Nicotine delivery systems not directly reliant on tobacco are also emerging (eg, electronic nicotine delivery systems). The presence of such products presents challenges and opportunities for public health. Future regulatory actions such as expansion of smoke-free environments, product health warnings and taxation may serve to increase or decrease the use of non-cigarette forms of tobacco. These regulations may also bring about changes in non-cigarette tobacco products themselves that could impact public health by affecting attractiveness and/or toxicity.  相似文献   

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《Journal of dairy science》2023,106(6):4266-4274
The objective of this narrative review was to compare the results of the 2015 Canadian National Dairy Study and the 2014 US National Animal Health Monitoring System (NAHMS) Dairy Studies, with a specific focus on calf management and welfare, and to interpret these findings within more recent calf health research to describe where we need to go next in the North American dairy industry. Situating results of periodic national studies within the context of past and recent research provides an opportunity to gauge adoption of recommendations and best practices and to help identify persistent and new challenges that the industry is wrestling with to help guide research needs. Through this review of the 2 national studies, we identified several strengths of the Canadian and US dairy industries. In each area of calf health management, improvements relative to previous NAHMS studies and the published literature have been found in the level of mortality, amount of colostrum fed, housing, and the number of producers using pain control for disbudding and dehorning. There were, however, some areas that present clear opportunities for improvement. Specifically, although mortality levels have improved, a large number of calves die at birth, within the first 48 h of life, and during the preweaning period. To improve the health of calves in early life, producers could look at feeding high-quality colostrum at 10% of body weight in the first feeding, as well as feeding a larger amount of milk during the preweaning period. The barriers to making these management changes and improving overall calf health need to be identified in future studies. The majority of preweaning calves in Canada and the United States are housed in individual housing. This represents a clear opportunity for improvement because recent research has identified the positive aspects of group housing. Finally, with respect to pain control, improvements are needed (particularly in the United States) to ensure that pain management is provided when disbudding and dehorning calves. Although the science is clear on pain management, discussions with producers are needed to identify reasons for the lack of uptake.  相似文献   

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Changes in nitrate concentration and flux between 1980 and 2008 at eight sites in the Mississippi River basin were determined using a new statistical method that accommodates evolving nitrate behavior over time and produces flow-normalized estimates of nitrate concentration and flux that are independent of random variations in streamflow. The results show that little consistent progress has been made in reducing riverine nitrate since 1980, and that flow-normalized concentration and flux are increasing in some areas. Flow-normalized nitrate concentration and flux increased between 9 and 76% at four sites on the Mississippi River and a tributary site on the Missouri River, but changed very little at tributary sites on the Ohio, Iowa, and Illinois Rivers. Increases in flow-normalized concentration and flux at the Mississippi River at Clinton and Missouri River at Hermann were more than three times larger than at any other site. The increases at these two sites contributed much of the 9% increase in flow-normalized nitrate flux leaving the Mississippi River basin. At most sites, concentrations increased more at low and moderate streamflows than at high streamflows, suggesting that increasing groundwater concentrations are having an effect on river concentrations.  相似文献   

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Zebras in Russia! Where next?   总被引:1,自引:1,他引:0       下载免费PDF全文
The zebra may seem an odd choice as a brand image for a new cigarette in Russia, but subtle tobacco marketing forces are, as always, at work.  相似文献   

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Lactation is a physiological event that is exclusive to mammals. Lactation evolved as a strategy to improve the survival of the young by providing them with the complete nutrition that is required for survival upon birth as well as maternal–offspring bonding. Typically, milk production by the dam matches the demand of the young. The dairy cow is a unique exception in which the discoveries and genetic selection related to lactation physiology have been applied and resulted in a dramatic increase in milk yield of dairy cows. Studies on the role of mammary-derived serotonin and the coordination of various aspects of milk production and maternal metabolism have revealed novel mechanisms by which milk production and maternal metabolism can be improved. Furthermore, the investigation into molecular and cellular mechanisms regulating mammary gland function has revealed the importance of epigenetics on mammary gland function. Understanding mammary gland function at the cellular and physiological levels will be important for improving mammary gland control of maternal metabolism during early lactation. The early lactation period is a critical time for a dairy cow as that is when she is most susceptible to disease and metabolic disorders that can lead to negative effects on her productive capacity and overall health. Our research in the area of serotonin physiology has illustrated the importance of serotonin on the regulation of lactation and maternal homeostasis. Future research in the area of lactation physiology should be targeted at improving maternal health and longevity in the herd through manipulation of the signals the mammary gland sends to coordinate maternal metabolism and synthesize milk. Specifically, we believe that serotonin will play a central role in understanding the communication between the mammary gland and the maternal physiology during lactation.  相似文献   

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Efficiency is a term generally used to determine how well a system performs. However, efficiency can have different meanings and, unaccompanied by a formal definition or taken out of context, can lead to serious misconceptions. In many official publications, efficiency is calculated as the ratio of useful output to energy input. This measure reflects the first law of thermodynamics (conservation of energy) but does not reflect the potential for improvement. A better measure, that also reflects the second law of thermodynamics, is the ratio of the potential useful (exergy) output to the potential useful (exergy) input. We estimate second law efficiencies for the inorganic and organic chemical industries to be 29% and 35% respectively. We also estimate the efficiency of the U.S. industry sector as a whole to be 37.6%, as compared to only 7.7% for the overall U.S. economy. These figures are far lower than the "first law" figures published by the U.S. Department of Energy (80% for industry and 42.5% overall) and they imply a significant potential for improvement.  相似文献   

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《Food quality and preference》2001,12(5-7):345-351
The target of our considerations is whether or not we can find significant differences between subgroups of consumers with respect to given hedonic variables. For this purpose a STATIS-consensus is computed for each group and the dissimilarities between groups are judged with the help of the RV-coefficient. Since the distribution of this coefficient is unknown and we do not make any assumptions on the distribution of the error terms, a permutation test is performed. This provides a simple possibility to test for significance of the dissimilarities in question. Some pre-treatment of the data is necessary to perform this statistical test. Afterwards subgroups according to the two sets of consumer tests, the different geographies and some of the classification variables within consumer test 1 are considered. When significant dissimilarities are found, a graphical representation of the respective consensuses is provided to interpret the differences.  相似文献   

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Escherichia coli O157:H7 is but one of a group of Shiga toxin-producing E. coli (STEC) that cause both intestinal disease such as bloody and nonbloody diarrhea and serious complications like hemolytic uremic syndrome (HUS). While E. coli O157: H7 is the most renowned STEC, over 200 different types of STEC have been documented in meat and animals, at least 60 of which have been linked with human disease. A number of studies have suggested that non-O157 STEC are associated with clinical disease, and non-O157 STEC are present in the food supply. Non-O157 STEC, such as O111 have caused large outbreaks and HUS in the United States and other countries. The current policy in the United States is to examine ground beef for O157:H7 only, but restricting the focus to O157 will miss other important human STEC pathogens.  相似文献   

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Humic substances in soils: are they really chemically distinct?   总被引:2,自引:0,他引:2  
Humic substances (HS) are an operationally defined fraction of soil organic matter, and they represent the largest pool of recalcitrant organic carbon in the terrestrial environment. It has traditionally been thought that extractable HS consist of novel categories of cross-linked macromolecular structures. In this study, advanced nuclear magnetic resonance approaches were used to study the major components (proteins, carbohydrates, aliphatic biopolymers, and lignin) that are known to be present in HS, and to identify their fingerprints in humic mixtures. Theoretically, once all known components have been identified, the remaining signals should be from materials with novel structures, themselves forming a distinct chemical category of humic materials. Surprisingly, nearly all of the NMR signals in traditional HS fractions could be assigned to intact and degrading biopolymers. We therefore suggest that the vast majority of operationally defined humic material in soils is a very complex mixture of microbial and plant biopolymers and their degradation products but not a distinct chemical category. It is important to note this work in no way rules out the existence of a distinct category of humic macromolecules, either at low abundance in the soluble fraction from young soils, in diagenetically evolved samples (for example lignites, etc.), or in the nonextractable humin fraction.  相似文献   

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