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Exploring the influence of optical and thermal parameters on the effectiveness of parabolic trough collector receiver units

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Clean Energy 2024年第4期8卷 15-33页

作者： Khaled Mohamad Engineering and natural sciences Faculty SDU UniversityAlmatyKazakhstan

This study investigates the optimization of physical parameters in a parabolic trough collector receiver unit to improve its thermal and optical *** parameters include the transmissivity,reflectivity,absorptivity,emissivity and thermal conductivity of the outer cover and absorber *** study utilizes a novel experimental design and a simulation model that accounts for the infrared reflectivity inside the *** simulation results were validated by the experimental data,with a maximum deviation of 8%.The study analyses the effects of varying the physical parameters on the heat transfer fluid temperature,total plant efficiency,temperature profiles,temperature gradients and thermal *** study finds that increasing the reflectivity and decreasing the emissivity of the outer cover and the absorber pipe significantly enhance the performance,with maximum increases of 25.8%and 26.5%in total efficiency,*** study also finds that increasing the thermal conductivity of the absorber pipe reduces the temperature gradients and thermal stress,with maximum decreases of 42.2%and 29%,*** study provides valuable insights for optimizing the receiver design and operation in solar-thermal systems.

关键词： parabolic trough collector heat transfer fluid receiver unit outer cover absorber pipe

Tocotrienol isoforms:The molecular mechanisms underlying their effects in cancer therapy and their implementation in clinical trials

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Journal of Integrative Medicine 2024年第1期22卷 1-11页

作者： Maria Younes Ghady Loubnane Christopher Sleiman Sandra Rizk Department of natural sciences Lebanese American UniversityByblosLebanon

Tocotrienols are found in a variety of natural sources,like rice bran,annatto seeds and palm oil,and have been shown to have several health-promoting properties,particularly against chronic diseases such as *** incidence of cancer is rapidly increasing around the world,not only a result of continued aging and population growth,but also due to the adoption of aspects of the Western lifestyle,such as high-fat diets and low-physical *** literature provides strong evidence that tocotrienols are able to inhibit the growth of various cancers,including breast,lung,ovarian,prostate,liver,brain,colon,myeloma and pancreatic *** findings,along with the reported safety profile of tocotrienols in healthy human volunteers,encourage further research into these compounds’potential use in cancer prevention and *** current review provided detailed information about the molecular mechanisms of action of different tocotrienol isoforms in various cancer models and evaluated the potential therapeutic effects of different vitamin E analogues on important cancer hallmarks,such as cellular proliferation,apoptosis,angiogenesis and ***/PubMed and Scopus databases were used to identify recently published articles that investigated the anticancer effects of vitamin E derivatives in various types of cancer in vitro and in vivo along with clinical evidence of adjuvant chemopreventive *** an overview of pre-clinical studies,we describe several completed and ongoing clinical trials that are paving the way for the successful implementation of tocotrienols in cancer chemotherapy.

关键词： Vitamin E Tocotrienols Cancer Molecular mechanism Clinical trials

Height-diameter models for King Boris fir(Abies borisii regis Mattf.) and Scots pine(Pinus sylvestris L.) in Olympus and Pieria Mountains, Greece

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Journal of Mountain Science 2024年第5期21卷 1475-1490页

作者： Dimitrios I.RAPTIS Dimitra PAPADOPOULOU Angeliki PSARRA Athanasios A.FALLIAS Aristides G.TSITSANIS Vassiliki KAZANA Renewable natural Resource Management and Bioeconomy Laboratory Department of Forest and Natural Environment SciencesInternational Hellenic University66100 DramaGreece

In forest science and practice, the total tree height is one of the basic morphometric attributes at the tree level and it has been closely linked with important stand attributes. In the current research, sixteen nonlinear functions for height prediction were tested in terms of their fitting ability against samples of Abies borisii regis and Pinus sylvestris trees from mountainous forests in central Greece. The fitting procedure was based on generalized nonlinear weighted regression. At the final stage, a five-quantile nonlinear height-diameter model was developed for both species through a quantile regression approach, to estimate the entire conditional distribution of tree height, enabling the evaluation of the diameter impact at various quantiles and providing a comprehensive understanding of the proposed relationship across the distribution. The results clearly showed that employing the diameter as the sole independent variable, the 3-parameter Hossfeld function and the 2-parameter N?slund function managed to explain approximately 84.0% and 81.7% of the total height variance in the case of King Boris fir and Scots pine species, respectively. Furthermore, the models exhibited low levels of error in both cases(2.310m for the fir and 3.004m for the pine), yielding unbiased predictions for both fir(-0.002m) and pine(-0.004m). Notably, all the required assumptions for homogeneity and normality of the associated residuals were achieved through the weighting procedure, while the quantile regression approach provided additional insights into the height-diameter allometry of the specific species. The proposed models can turn into valuable tools for operational forest management planning, particularly for wood production and conservation of mountainous forest ecosystems.

关键词： Generalized nonlinear weighted regression Monte Carlo cross-validation Mountainous ecosystems Quantile regression Central Greece

End-Triassic storm deposits in the lacustrine Sichuan Basin and their driving mechanisms

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Science China Earth sciences 2024年第7期67卷 2383-2400页

作者： Jianli ZENG Tingshan ZHANG Mihai Emilian POPA Yongdong WANG Xi ZHANG Liqin LI Yuanyuan XU Ning LU Xiaoqing ZHANG School of Geoscience and Technology Southwest Petroleum University Chengdu 610500China Sichuan Key Laboratory of natural Gas Geology Southwest Petroleum University Chengdu 610500China Faculty of Geology and Geophysics Doctoral Schoolof Geology Laboratory of Palaeontology University of Bucharest.Bucharest 010041Romania Nanjing Institute of Geology and Palaeontology Chinese Academy of sciences Nanjing 210008China University of Chinese Academy of sciences NanjingNanjing 210008China University of Chinese Academy of sciences Beijing 100049China

Storm deposits or tempestites are event sequences formed by storms,requiring at least a water temperature of 26.5℃.While inland lakes are unlikely to form storm deposits because of their limited width and water *** Upper Triassic Xujiahe Formation in the Sichuan Basin is a set of coal-bearing,clastic sequences with dominant sedimentary facies varying from braided river delta to lacustrine settings,with storm deposits widely *** the Zilanba of Guanyuan area,in situ tree trunks on a palaeosol surface in Member Vof the Xujiahe Formation provide new evidence of a storm *** fallen-down directions of nine in situ tree trunks were predominant in the NW direction,contrary to the palaeocurrent direction of the underlying strata,suggesting that the southeasterlies prevailed during the end-Triassic in the northern Sichuan *** mud clasts were frequently recorded in sandstones of the Xujiahe Formation,as well as in the Xindianzi *** mud clasts showed a rip-up or a plastic deformation with upside-down V-shapes,were capped on an erosional surface,showed no transport traces and were therefore interpreted as a storm lag *** megamonsoonal climate prevailed during the Late Triassic,although the megamonsoons themselves could not generate a storm deposition in the Xujiahe Formation due to its low maximum surface wind *** driving mechanism for generating storm deposits in the Xujiahe Formation is suggested to be tropical cyclones over the Tethys Ocean moving eastward,further landfalling on the western margin of the Sichuan *** of storm events in the circum-Tethys region show a widespread storm surge in low latitudes during the *** storm deposits at the top of the Xujiahe Formation represent a sedimentary response to the end-Triassic hyperthermal event.

关键词： Sichuan Basin End-Triassic Xujiahe Formation Storm deposits

Dieback of managed spruce stands in western Germany promotes beetle diversity

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Journal of Forestry Research 2024年第3期35卷 55-71页

作者： Eva Plath Chantal Trauth Jan Gerhards Laura Griebel Klaus Fischer Department Biology Institute of Integrated Natural SciencesKoblenz-Landau University56070 KoblenzGermany

Biodiversity loss is a significant problem at a global scale and may be amplified by climate *** recent years,coniferous forests have had substantial die-back across Europe due to drought and subsequent bark-beetle *** many studies on the consequences of disturbance and subsequent management have focused on natural stands,management implications for managed spruce stands are not well understood,even though such stands are widespread throughout *** this study,beetle taxonomy,conservation value,and community com-position are compared among spruce plantations and four post-disturbance management approaches:standing dead-wood,lying deadwood,clear cuts,and long-term *** and community composition differed significantly among management categories,while different beetle fami-lies responded *** spruce stands harbored the lowest beetle diversity while the highest taxonomic diver-sity and conservation value was on clear cuts and stands with lying or standing *** proportion of forest specialists was highest in successional *** summary,different forest management categories harbored distinct beetle communities at the family-,species-,and ecological guild ***,post-disturbance management should consider the landscape scale and include different management *** enhances landscape heterogeneity and thus overall biodiversity but could also mitigate negative impacts of natural disturbances on ecosystem services.

关键词： Bark-beetle outbreak Forest dieback Spruce Deadwood Nature conservation Beetle biodiversity-Coleoptera Coniferous forests

Challenges and opportunities in the production of magnesium parts by directed energy deposition processes

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Journal of Magnesium and Alloys 2024年第5期12卷 1663-1686页

作者： Gürel Cam Ali Günen Iskenderun Technical University Faculty of Engineering and Natural SciencesDepartment of Mechanical Engineering31200 Iskenderun-HatayTurkey Iskenderun Technical University Faculty of Engineering and Natural SciencesDepartment of Metallurgy and Materials Engineering31200 Iskenderun-HatayTurkey

Mg-alloys have gained considerable attention in recent years for their outstanding properties such as lightweight,high specific strength,and corrosion resistance,making them attractive for applications in medical,aerospace,automotive,and other transport ***,their widespread application is hindered by their low formability at room temperature due to limited slip *** Mg-alloys have low mechanical properties due to the presence of casting defects such as porosity and anisotropy in addition to the high *** casting methods benefit from established process optimization techniques for these problems,additive manufacturing methods are increasingly replacing casting methods in Mg alloys as they provide more precise control over the microstructure and allow specific grain orientations,potentially enabling easier optimization of anisotropy properties in certain *** metal additive manufacturing(MAM)technology also results in some manufacturing defects such as inhomogeneous microstructural evolution and porosity and additively manufactured Mg alloy parts exhibit lower properties than the wrought parts,they in general exhibit superior properties than the cast ***,MAM is a promising technique to produce Mg alloy *** energy deposition processes,particularly wire arc directed energy deposition(WA-DED),have emerged as an advantageous additive manufacturing(AM)technique for metallic materials including magnesium alloys,offering advantages such as high deposition rates,improved material efficiency,and reduced production costs compared to subtractive ***,the inherent challenges associated with magnesium,such as its high reactivity and susceptibility to oxidation,pose unique hurdles in the application of this *** review paper delves into the progress made in the application of DED technology to Mg-alloys,its challenges,and ***,the predominant imperfections,notably inhomo

关键词： Additive manufacturing DED processes Arc-DED Wire arc additive manufacturing(WAAM) 3-D printing High deposition rate

Impact of tourism on the vigilance behavior of the Cyprus rock agama(Laudakia cypriaca)

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Integrative Zoology 2024年第3期19卷 577-583页

作者： Artur GOLAWSKI Iris CHARALAMBIDOU Sylwia GOLAWSKA Faculty of sciences Siedlce University of Natural Sciences and HumanitiesSiedlcePolandand Department of Life sciences School of Life and Health SciencesUniversity of NicosiaNicosiaCyprus

Escape behavior is a common antipredator strategy among wild ***,we investigated the effect of four factors on the vigilance behavior of the endemic Cyprus rock agama(Laudakia cypriaca).Flight initiation distance(FID,the minimum distance to which an observer can approach a lizard before it flees)was measured in relation to the type of location(tourist *** area),the observer’s starting distance,air temperature,and substrate *** collected data for 39 agamas in tourist areas and 34 of these lizards in nontourist *** a whole,the mean starting distance was 10.5 m and the FID was 3.6 *** average substrate temperature was 34.0℃ and the average air temperature 29.6℃.Only the type of area affected the agamas’escape decisions with FID being 1.8 m shorter in tourist areas than in nontourist areas(2.7 m vs.4.5 m).This is probably due to the habituation of lizards to the presence of humans in the former *** study shows that tourism strongly affects the behavior of lizards,which may have consequences for the functioning of the *** can increase the safety of lizards by creating a human shield to deter *** the tourist season is over,lizards may become more vulnerable to predators.

关键词： anthropogenic disturbance flight initiation distance lizards tourism vigilance behavior

Tracing suspended and bed sediments during high and low water periods using geochemical characteristics-Case study:Vazrood watershed,northern Iran

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Journal of Mountain Science 2024年第2期21卷 470-483页

作者： KARIMI Nabiyeh GHOLAMI Leila KAVIAN Ataollah KHALEDI DARVISHAN Abdulvahed Department of Watershed Management Faculty of Natural ResourcesSari Agricultural Sciences and Natural Resources UniversitySari ***Iran Department of Watershed Management Engineering Faculty of Natural ResourcesTarbiat Modares UniversityNoor ***Iran

Complete and comprehensive information about sediment dynamic and identification of hotspots of sediment production and transport are necessary for understanding the erosion processes and increasing the efficiency of soil and water conservation *** studies used the sediment fingerprint techniques to investigate the contribution of different sources in suspended and bed sediment yield of the ***,the contribution of various land use/land covers in suspended and bed sediment yield for the great Caspian Sea basin is in an aura of ambiguity and the present study was conducted to gather information about an important part of this area in northern Iran,where rangelands are located upstream of Hyrcanian forests and dense agricultural lands are located *** surface soil of different land use/land covers including forest,rangeland,agriculture and streambank lands were sampled in 30 *** and bed sediments were sampled in the watershed outlet in two high and low water *** characteristics of soil and sediment samples containing 59 elements were measured using ICP-OES GBC *** reliable and suitable tracers from 59 elements were then selected using Range test,Kruskal-Wallis and Discriminant Function Analysis,respectively,in FingerPro package of R *** results showed that for suspended sediment,streambank and rangeland had the highest contributions of 86.2%and 47.5%,respectively,in two high and low water *** bed sediment,in two high and low water periods,rangeland and streambank had the highest contributions of 73.8%and 84.4%,*** use change and especially human activities such as agriculture,road construction and development of residential areas along the main river riparian zone has led to a significant increase in suspended and bed sediments.

关键词： Caspian Sea basin FingerPro Geochemistry Sediment transport Tracer combination

A comprehensive review on pharmacognosy, phytochemistry and pharmacological activities of 8 potent Prunus species of southeast Asia

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Journal of Traditional Chinese Medicine 2024年第3期44卷 620-628页

作者： Shikha Agrawal Adarsh Kumar Ankit Kumar Singh Harshwardhan Singh Suresh Thareja Pradeep Kumar Department of Pharmaceutical sciences and natural Products Central University of PunjabBathinda 151401India

Genus Prunus comprising around 430 species is a vast important genus of family Rosaceae, subfamily amygdalaoidae. Among all 430 species, around 19 important species are commonly found in Indian subcontinent due to their broad nutritional and economic importance. Some most common species of genus Prunus are Prunus amygdalus, Prunus persica, Prunus armeniaca, Prunus avium, Prunus cerasus, Prunus cerasoides, Prunus domestica, Prunus mahaleb, etc. A newly introduced species of Prunus i.e Prunus sunhangii is recently discovered which is morphologically very similar to Prunus cerasoides. Plants of Prunus species are short to medium-sized deciduous trees mainly found in the northern hemisphere. In India and its subcontinent,it extends from the Himalayas to Sikkim, Meghalaya,Bhutan, Myanmar etc. Different Prunus species have been extensively studied for their morphological,microscopic, pharmacological and phytoconstituents characteristics. Total phenolic content of Prunus species explains the presence of phenols in high quantity and pharmacological activity due to phenols. Phytochemical screening of species of genus Prunus shows the presence of wide phytoconstituents which contributes in their pharmacological significance and reveals the therapeutic potential and traditional medicinal significance of this genus. Genus Prunus showed a potent antioxidant activity analyzed by 1,1-diphenyl-2-picryl-hydrazyl radical assay. Plant species belonging to the genus Prunus is widely used traditionally for the treatment of various disorders. Some specific Prunus species possess potent anticancer, anti-inflammatory,hypoglycemic etc. activity which makes the genus more interesting for further research and findings. This review is an attempt to summarize the comprehensive study of Prunus species from its distribution, morphological characters to phytoconstituents, and pharmacological activity.

关键词： Rosaceae Prunus antineoplastic agents hypoglycemic agents distribution phytochemistry review