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In-situ probing of thermal desorption of vapor molecules on a nanowire via work function variance

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Nano research 2016年第11期9卷 3334-3345页

作者： Kovur Prashanthi John Eric hawk ryan McGee ravi Gaikwad Thomas Thundat Ingenuity Lab Department of Chemical and Materials Engineering University of Alberta Edmonton AB T6G 2V4 Canada

Nanowire sensors based on variations of their electrical properties show great potential for real-time, in situ monitoring of molecular adsorption and desorption. Although the molecular adsorption-induced change in the electronic work function is very sensitive, it does not have any specificity. However, the temperature dependency of the adsorption-induced work function variation can provide limited selectivity based on the desorption temperature. In this study, we report the in situ probing of molecular desorption by monitoring the work function variations of a single Pt nanowire as a function of temperature. The work function of a clean Pt nanowire shows a significant variation due to vapor adsorption at room temperature. Increasing the temperature of the nanowire results in a variation of the work function due to molecular desorption. Experimentally measured differential work function as a function of temperature shows desorption peaks at 36 and 44 ℃ for methanol and ethanol molecules respectively. Adsorption-induced variation of the Pt nanowire work function was further confirmed using ultraviolet photoelectron spectroscopy before and after exposure to methanol vapor. These results show that the molecular adsorption/desorption-induced variation of the work function and its temperature dependency can be used for developing nanoscale electro-calorimetric sensors.

关键词： Kelvin probe microscopy nanowires thermal desorption work function

Coupling physics in machine learning to predict properties of high-temperatures alloys

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npj Computational Materials 2020年第1期6卷 477-483页

作者： Jian Peng Yukinori Yamamoto Jeffrey A.hawk Edgar Lara-Curzio Dongwon Shin Materials Science and Technology Division Oak Ridge National LaboratoryOak RidgeTN 37831USA Materials Performance Division National Energy Technology LaboratoryAlbanyOR 97321-2198USA

High-temperature alloy design requires a concurrent consideration of multiple mechanisms at different length *** propose a workflow that couples highly relevant physics into machine learning(ML)to predict properties of complex high-temperature alloys with an example of the 9–12 wt% Cr steels yield *** have incorporated synthetic alloy features that capture microstructure and phase transformations into the *** high impact features that affect yield strength of 9Cr from correlation analysis agree well with the generally accepted strengthening mechanism.

关键词： alloys alloy strength

Machine-learning informed prediction of high-entropy solid solution formation:Beyond the Hume-rothery rules

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npj Computational Materials 2020年第1期6卷 1288-1295页

作者： Zongrui Pei Junqi Yin Jeffrey A.hawk David E.Alman Michael C.Gao National Energy Technology Laboratory AlbanyOR 97321USA OrISE 100 ORAU WayOak RidgeTN 37830USA Oak ridge National Laboratory Oak RidgeTN 37831USA Leidos research Support Team AlbanyOR 97321USA

The empirical rules for the prediction of solid solution formation proposed so far in the literature usually have very compromised *** rules with seemingly good predictability were,however,tested using small data *** on an unprecedented large dataset containing 1252 multicomponent alloys,machine-learning methods showed that the formation of solid solutions can be very accurately predicted(93%).The machine-learning results help identify the most important features,such as molar volume,bulk modulus,and melting temperature.

关键词： temperature prediction alloys

AUTOrADIOGrAPHIC STUDY OF THE ATTrITION OF MIGrATING SCHISTOSOMULA IN THE SKIN OF MICE *** CHALLENGED WITH NOrMAL *** CErCArIAE AFTEr IMMUNIZATION WITH HIGHLY IrrADIATED CErCArIAE

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Chinese Medical Sciences Journal 1990年第1期8卷 30-36页

作者： S.Y.Li Hsu H.F.Hsu J.W.Osborne W.r.Clarke C.K.hawk Y.Ohnishi College of Medicine University of IowaIowaUSA

The migratory pattern and attrition of75Se-labelled *** challenge cercariae in CF1mice immunized 0,1,3, or 5 times with 12kr-or 48kr-irradiated cercariae were investigatedby compressed organ *** were percutaneously inoculated with 500-1000 cer-cariae for each immunization and with a known count of approximately 90 cercariae at adifferent site for *** skin,lungs,liver,other organs,and catrcass were processedfor *** and mesenteric perfusions for worm collection were alsosampled from day 19 through *** naive tnice,25% of challenge cercariae died in *** attrition of challenge cercariae in mice immunized with 12kr-irradiated cercariaewas 43% with 1 immunization,54% with 3,and 58% with 5,whereas in mice immunized with48kr-irradiated cercariae,skin,attrition was48% with 1,63% with 3,and 76% with 5 *** all immunized mice,a high percentage of migrating sehistosomula died in the skinwithin 24 hours of a challenge *** autoradiography,it was found that thesilver foci created by single labelled worms were difficult to differentiate from those of *** study documents the induction of acquired resistance against a challenge infectionin the skin by vaccination with highly irradiated cercariae,with the degree of attemtation ofimmunizing cercariae and the number of immunizations being closely related to the *** in the ***,we discuss the contradictory views concerning the site of attritiotn ofchallenge cercariae.

关键词： autoradiography attrition—challenge cercariae immunization—highly X-irradiated cercariae Schistosoma mansoni

The effects of aging on muscle loss and tissue-specific levels of NF-<i>κ</i>B and SIrT6 proteins in rats

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Advances in Aging research 2013年第1期2卷 1-9页

作者： Tiev C. LaGuire Corinne r. Kohlen Susan N. hawk Scott K. reaves Department of Nutrition Exercise and Health Sciences Central Washington University Ellensburg USA Food Science and Nutrition Department California Polytechnic State University San Luis Obispo USA

The objective of this study was to examine the influence of aging on food intake, tissue and organ mass and NF-κB and SIrT6 levels in various tissues. The transcription factor, Nuclear Factor Kappa-B (NF-κB), is associated with both catabolic and anabolic pathways of muscle metabolism and may be involved in age-related muscle loss. SIrT6 is a member of the sirtuin family of proteins that function as protein lysine deacetylases and are associated with longevity in a number of organisms. Male Sprague-Dawley rats, aged 6 months (Adult) and 21 months (Old) were fed a commercially available diet for 10-17 days. Old rats consumed less food per body weight (BW) each day than Adult rats (1.45% g diet/g BW vs. 2.4% g diet/g BW). However, when intake data were expressed as g/diet per day there was no significant difference between groups. For skeletal muscle tissue, the average mass of gastrocnemius and soleus (g muscle/g BW) was significantly lower in Old rats. Levels of NF-κB (p65/relA) and SIrT6 were measured by Western blot analysis in gastrocnemius, tibialis anterior, quadriceps, soleus, lung, heart, kidney and liver. NF-κB levels were higher in gastroc- nemius of Old rats compared to Adult rats. No significant age-specific differences in SIrT6 protein levels were noted in the tissues examined. Interestingly, when examined independent of age, levels of SIrT6 were significantly different between certain tissues. Data from this study suggest that aging affects muscle loss and NF-κB in a tissue-specific manner. Furthermore, these findings indicate tissue-specific but not age-specific differences in SIrT6 protein levels.

关键词： rat NF-κB SIrT6 Muscle Atrophy Proteolysis

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CSS ***泾渭分明的下一代BIOS

微型计算机 2004年第2期24卷 19-20页

作者： hawk

20年不变的BIOS已经让使用者习以为常，似乎没有中文说明．没有图片都没关系，只要功能够用就可以了．然而BIOS真的已经趋予完美了吗？事实并非如此。到底未来的BlOS会是什么样的？还是让我们看看微软和Intel给出的答案吧。

关键词： BIOS CSS EFI 图形界面

The Effects of n-3 Fatty Acids and Bexarotene on Breast Cancer Cell Progression

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Journal of Cancer Therapy 2011年第5期2卷 710-714页

作者： Jessica Trappmann Susan N. hawk 不详

Breast cancer cell growth can be inhibited in vivo by retinoid X receptor (rXr) specific retinoids. In both animal and cell culture studies, omega-3 fatty acids share growth regulatory effects similar to those of rXr specific retinoids (rexinoids). One synthetic rexinoid, bexarotene (LCD 1069, Targretin), is used clinically to treat cancer patients. Of concern is that some patients are unable to tolerate high doses of such treatment drugs. We hypothesized that n-3 fatty acids and bexarotene may work synergistically to slow breast cancer cell growth. To test our hypothesis, we used MCF-7 human mammary carcinoma cells and an in vitro cell culture model. We investigated the relationship between the omega-3 fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) alone and in conjunction with bexarotene in slowing MCF-7 cell growth. Following a 72 hr incubation with the respective treatments, bexarotene enhanced cell growth (p rong growth inhibitory effect which was not enhanced by the addition of bexarotene (p ring cell growth (p restingly, when combined with bexarotene, EPA was more effective at slowing cell growth than when cells received EPA alone. Thus, select omega-3 fatty acids alone are more effective than bexarotene in slowing MCF-7 cell progression. However, the use of the rXr-selective retinoids may enhance the growth regulatory mechanisms of the fatty acid EPA.

关键词： Bexarotene Breast Cancer Docosahexaenoic Acid Omega-3 Fatty Acid MCF-7

Prey reduce risk-taking and abundance in the proximity of predators

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Current Zoology 2017年第6期63卷 591-598页

作者： Anders. r MФLLEr Zbigniew KWIECINSKI Piotr TrYJANOWSKI Ecologie Systematique Evolution Universite Paris-Sud CNRS AgroParisTech Universite Paris-Saclay Orsay Cedex F-91405 France blnstitute of Zoology Poznan University of Life Science Wojska Polskiego 71C Poznan PL-60-625 Poland

Prey have evolved anti-predator defences that reduce or eliminate the risk of predation. Predators often reproduce at specific sites over many years causing permanent threats to local prey species. Such prey may respond by moving elsewhere thereby reducing local population abundance, or they may stay put and adjust their behavior to the presence of predators. We tested these predictions by analyzing population abundance and anti-predator behavior within 100 m of and 500 m away from nests of sparrowhawks Accipiter nisus and goshawks A. gentilis for 80 species of birds. Population abundance of prey was reduced by 11% near goshawk nests and by 15% near sparrowhawk nests when compared with nearby control sites in similar habitats. Flight initiation distance （FID） of prey, estimated as the distance at which birds took flight when approached by a human, increased by 50% in the presence of hawk nests, providing evidence of adjustment of anti-predator behavior to prevailing risks of predation. Susceptibility to predation was estimated as log transformed abundance of the observed number of prey items obtained from prey remains collected around nests minus log transformed expected number of prey according to point counts of breeding birds. FID increased from 10 to 46 m with increasing susceptibility of prey species to predation by the goshawk and from 12 to 15 m with increasing susceptibility of prey species to predation by the sparrowhawk. These findings suggest that prey adjust their distribution and anti-predator behavior to the risk of predation.

关键词： accipiter hawks FID flight initiation distance goshawk population abundance prey preference sparrowhawk.

risks of iron deficiency among vegetarian college women

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Health 2012年第3期4卷 113-119页

作者： Susan N. hawk Kimberly Grage Englehardt Cindi Small Department of Food Science and Nutrition California Polytechnic State University San Luis Obispo USA Department of Nutrition Health and Exercise Science Central Washington University Ellensburg USA

Iron deficiency anemia is the most common nutritional deficiency disease worldwide and poses a major threat in women of child-bearing age and those who follow a vegetarian diet. The objective of this study was to ascertain whether differences exist in iron status markers between female university students following a vegetarian and non-vegetarian diet. This study took a cross sectional analysis of 39 female students at California Polytechnic State University (Cal Poly State University) in San Luis Obispo, CA between the ages of 18 and 22. Of the participants, 19 followed a vegetarian diet and 20 followed a nonvegetarian diet. Characteristic, demographic, and anthropometric data were collected and analyzed. The results showed no significant difference in iron intake between the two groups. However, nearly 66% of vegetarians and 65% of non-vegetarians failed to meet the recommended Daily Allowance for iron. No significant difference was found for serum iron, serum ferritin, transfer-rin saturation, and total iron binding capacity between subjects. Serum ferritin tended to be lower for vegetarians compared to non-vegetarians. Both vegetarians and non-vegetarians were in stage IV negative iron balance, with more vegetarians tending to be in stage IV negative iron balance than non-vegetarians. Thus, female college students, irrespective of their meat intake, may be at higher risk of developing negative iron balance and should be educated about iron deficiency anemia and the prevention of iron depletion.

关键词： Iron Anemia Vegetarian Negative Iron Balance