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Exploring University Campus Community’s Perceptions and Barriers toward Biking: A Case Study of the University of Tennessee Knoxville
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作者 Sheikh Muhammad Usman Muhammad Adeel 《Journal of Transportation Technologies》 2024年第2期161-178,共18页
Bicycling constitutes an integral component of sustainable non-motorized means of travel. Despite the immense benefits of bicycling, the modal share of bicycling is quite low, specifically among young and low-income c... Bicycling constitutes an integral component of sustainable non-motorized means of travel. Despite the immense benefits of bicycling, the modal share of bicycling is quite low, specifically among young and low-income commuters e.g., college and university students. This study explores the perceptions of and barriers to bicycling of the campus community at the University of Tennessee, Knoxville with the aim to identify the factors that could enhance bike use among students at the university campus as well as highlight the barriers that keep young population away from biking. An online survey about bike use at the university campus was administered and responses to the survey were recorded. On the methodological front, a binary logit model was estimated with students’ willingness to use bikes at campus as the dependent variable. The survey results revealed that about 47% of the students considered vehicular traffic as the reason for feeling unsafe while biking and emphasized having separate bike routes. Most of the respondents highlighted the need to change clothes after biking in summer or carry things as the reason for not selecting bikes as a mode of transport at the campus, whereas inadequate bike lanes, paths, or trails, insufficient lighting along bike routes, and the lack of adequate bicycle parking were highlighted as the major barriers deterring bike use within the campus. The study suggests development of a campus bike network with proper bike lanes, bike runnels, installation of safety cameras and better lighting at the campus, and bike-supporting infrastructure such as communal showers to be provided in campus buildings to encourage bike use among university students. The study findings can assist campus transportation planners in devising a sustainable campus transportation plan incorporating the influencing factors and deterrents of bike use in a university campus setting. 展开更多
关键词 Bike use Bike Infrastructure Educational Institutes Survey Binary Logit Model
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A 63-Year-Old Male with D-Transposition of the Great Arteries Who Had an Early Form of the Arterial Switch Operation
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作者 Michael A.Rebolledo Jane S.Yao +2 位作者 Jason N.Johnson Umar S.Boston Benjamin R.Waller III 《Congenital Heart Disease》 SCIE 2024年第1期65-68,共4页
We describe a 63-year-old male who appears to have undergone an early form of the arterial switch operation for D-transposition of the great arteries performed in the mid-1960s.We review the clinical and imaging data ... We describe a 63-year-old male who appears to have undergone an early form of the arterial switch operation for D-transposition of the great arteries performed in the mid-1960s.We review the clinical and imaging data that support our conclusion.He had a diagnostic cardiac catheterization which demonstrated severe pulmonary hypertension responsive to epoprostenol and oxygen.Our case may represent one example of the experimental surgical work done prior to Dr.Adibe Jatene’s description of thefirst successful arterial switch performed in 1975. 展开更多
关键词 Adult congenital heart disease arterial switch operation great vessel anomaly imaging(all modalities)
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Relationship between the unique microstructures and behaviors of high-entropy alloys
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作者 Yaqi Wu Peter KLiaw +5 位作者 Ruixuan Li Weiran Zhang Guihong Geng Xuehui Yan Guiqun Liu Yong Zhang 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第6期1350-1363,共14页
High-entropy alloys(HEAs),which were introduced as a pioneering concept in 2004,have captured the keen interest of nu-merous researchers.Entropy,in this context,can be perceived as representing disorder and randomness... High-entropy alloys(HEAs),which were introduced as a pioneering concept in 2004,have captured the keen interest of nu-merous researchers.Entropy,in this context,can be perceived as representing disorder and randomness.By contrast,elemental composi-tions within alloy systems occupy specific structural sites in space,a concept referred to as structure.In accordance with Shannon entropy,structure is analogous to information.Generally,the arrangement of atoms within a material,termed its structure,plays a pivotal role in dictating its properties.In addition to expanding the array of options for alloy composites,HEAs afford ample opportunities for diverse structural designs.The profound influence of distinct structural features on the exceptional behaviors of alloys is underscored by numer-ous examples.These features include remarkably high fracture strength with excellent ductility,antiballistic capability,exceptional radi-ation resistance,and corrosion resistance.In this paper,we delve into various unique material structures and properties while elucidating the intricate relationship between structure and performance. 展开更多
关键词 high-entropy alloys unique microstructure special properties alloy design
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Synthesis of 4-[F-18]Fluoro-4-Deoxy-N-Acetyl-1,3,6-Tri-O-Acetylglucosamine, a Potential Brain Imaging PET Agent
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作者 Murthy Akula Derek Cressy +2 位作者 Lee Collier George Kabalka Dustin Osborne 《Natural Science》 2024年第3期19-23,共5页
The synthesis of a promising brain imaging agent 4-[F-18]fluoro-4-deoxy-N-acetyl-1,3,6-tri-O-acetylglucosamine, 2, was successfully accomplished from commercially available N-acetyl glucosamine in 5 steps. The non-dec... The synthesis of a promising brain imaging agent 4-[F-18]fluoro-4-deoxy-N-acetyl-1,3,6-tri-O-acetylglucosamine, 2, was successfully accomplished from commercially available N-acetyl glucosamine in 5 steps. The non-decay corrected radiochemical yield and purity were found to be 31% ± 4% (n = 3) and >98% respectively. The total reaction time for radio labelling step was 50 min. 展开更多
关键词 N-ACETYLGLUCOSAMINE AMYLOIDOGENESIS Lipase-Candida rugosa
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Exercise and oncology:The role of physical activity in disease prevention and health promotion
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作者 Zan Gao Linda Trinh 《Journal of Sport and Health Science》 SCIE CAS CSCD 2023年第6期651-652,F0003,共3页
The field of exercise-oncology has evolved significantly over the past 30 years.Numerous studies have examined the role of structured exercise interventions—often incorporating aerobic or resistance training at moder... The field of exercise-oncology has evolved significantly over the past 30 years.Numerous studies have examined the role of structured exercise interventions—often incorporating aerobic or resistance training at moderate-to-vigorous intensities,sometimes in conjunction with multi-modal strategies—for individuals living with and beyond cancer. 展开更多
关键词 PREVENTION PROMOTION ONCOLOGY
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The Study on Bamboo Microfibers Isolated by Steam Explosion and Their Comprehensive Properties
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作者 Qiushi Li Ronggang Luo +9 位作者 Yu Chen Jinhui Xiong Bei Qiao Xijuan Chai Linkun Xie Juan Wang Lianpeng Zhang Siqun Wang Guanben Du Kaimeng Xu 《Journal of Renewable Materials》 SCIE EI 2023年第6期2809-2822,共14页
To overcome the shortage of wood resources as well as to develop novel natural fibers materials,the Chimonobambusa quadrangularis(CQ)and Qiongzhuea tumidinoda(QT)planted in Southwest China were effectively isolated by... To overcome the shortage of wood resources as well as to develop novel natural fibers materials,the Chimonobambusa quadrangularis(CQ)and Qiongzhuea tumidinoda(QT)planted in Southwest China were effectively isolated by the steam explosion(SE).The fine and uniform bamboo microfibers derived from CQ and QT were obtained,and their smallest average widths were 12.62μm and 16.05μm,respectively.The effects of steam explosion on the micro-morphology,chemical composition,thermal stability,crystallinity,surface wettability,and mechanical properties of bamboo microfibers were comprehensively investigated.The results showed that the relative content of cellulose in bamboo microfibers increased but the hemicellulose and lignin contents decreased after SE.The degrees of crystallinity for CQ and QT increased from 40.49%and 39.46%to 68.90%and 55.78%,respectively.The thermal stability and surface hydrophilicity were also improved.The CQ microfibers had a maximum decomposition temperature of 2.79°C,a tensile strength of 58.54 MPa,an elongation at break of 0.6%,and a water contact angle of 2.7°higher than those of the QT microfibers. 展开更多
关键词 Microfiber properties BAMBOO steam explosion Chimonobambusa quadrangularis Qiongzhuea tumidinoda
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Factorial Experimental Design to Study the Effects of Layers and Fiber Content on Concrete Flexural Behavior
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作者 Dumbiri H. Odia 《Open Journal of Civil Engineering》 CAS 2023年第1期83-102,共20页
Experimentation has come a long in helping researchers achieve breakthroughs in their different scientific areas and engineering happens to be one of those areas with the most impact from experimental advancement. The... Experimentation has come a long in helping researchers achieve breakthroughs in their different scientific areas and engineering happens to be one of those areas with the most impact from experimental advancement. The need for valid experimental results free from biases and confounding conclusions has prompted the development of new experimental techniques that takes consideration of all applicable factor and combinations in providing answers on a research topic, and the Factorial Experimental design credited to Sir Ronald Fisher is one technique yielding highly valid results. This paper uses the factorial design of experiments to research the flexural impact of polyvinyl acetate fiber and layered concrete in construction. The experiment considered two levels of fiber contents and two levels of layers, and prepared samples with all combinations of the variable factors. The samples were tested after 7 days from casting for flexural strength and an advance statistical analysis was performed on the flexural responses of the samples using R-program. The results from the analyses revealed the significance of the variables to the flexural strength of the samples, as well as their interactions. The experiment concluded that based on the number of layers and fiber content used for the experiment, casting concrete in layers does have a significant negative effect on the flexural strength of concrete, and the failure pattern of concrete members under flexural load in evidently influenced by the material composition of the concrete, and that it can be evidently influenced by casting the concrete in layers. 展开更多
关键词 Experimental Design Concrete Flexural Strength Factorial Design of Experiments Concrete Fibers Concrete Layers
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Modulation of p75 neurotrophin receptor mitigates brain damage following ischemic stroke in mice
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作者 Golnoush Mirzahosseini Tauheed Ishrat 《Neural Regeneration Research》 SCIE CAS CSCD 2024年第10期2093-2094,共2页
Stroke is a significant leading cause of death and disability in the United States(Tsao et al.,2022).Approximately 87% of strokes fall into the ischemic category,mainly caused by arterial blockage(Jayaraj et al.,2019)... Stroke is a significant leading cause of death and disability in the United States(Tsao et al.,2022).Approximately 87% of strokes fall into the ischemic category,mainly caused by arterial blockage(Jayaraj et al.,2019).Although the only FDA-approved effective medication is tissue plasminogen activator(tPA),it should be administrated within 4.5 hours of ischemic stroke.Furthermore,tPA has been an integral part of managing acute ischemic stro ke. 展开更多
关键词 damage ARTERIAL DEATH P75
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LSTM-based lane change prediction using Waymo open motion dataset: The role of vehicle operating space
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作者 Xing Fu Jun Liu +1 位作者 Zhitong Huang Alex Hainenand Asad J.Khattak 《Digital Transportation and Safety》 2023年第2期112-123,共12页
Lane change prediction is critical for crash avoidance but challenging as it requires the understanding of the instantaneous driving environment.With cutting-edge artificial intelligence and sensing technologies,auton... Lane change prediction is critical for crash avoidance but challenging as it requires the understanding of the instantaneous driving environment.With cutting-edge artificial intelligence and sensing technologies,autonomous vehicles(AVs)are expected to have exceptional perception systems to capture instantaneously their driving environments for predicting lane changes.By exploring the Waymo open motion dataset,this study proposes a framework to explore autonomous driving data and investigate lane change behaviors.In the framework,this study develops a Long Short-Term Memory(LSTM)model to predict lane changing behaviors.The concept of Vehicle Operating Space(VOS)is introduced to quantify a vehicle's instantaneous driving environment as an important indicator used to predict vehicle lane changes.To examine the robustness of the model,a series of sensitivity analysis are conducted by varying the feature selection,prediction horizon,and training data balancing ratios.The test results show that including VOS into modeling can speed up the loss decay in the training process and lead to higher accuracy and recall for predicting lane-change behaviors.This study offers an example along with a methodological framework for transportation researchers to use emerging autonomous driving data to investigate driving behaviors and traffic environments. 展开更多
关键词 Long Short-Term Memory Lane change prediction Vehicle Operating Space Waymo open data Sensitivity analysis
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Boron-containing compounds as labels,drugs,and theranostic agents for diabetes and its complications
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作者 Marvin A Soriano-Ursúa R Ivan Cordova-Chávez +1 位作者 Eunice D Farfan-García George Kabalka 《World Journal of Diabetes》 SCIE 2024年第6期1060-1069,共10页
Diabetes is a disease with a high global burden.Current strategies have failed to limit the advancement and impact of the disease.Successful early diagnosis and treatment will require the development of new agents.In ... Diabetes is a disease with a high global burden.Current strategies have failed to limit the advancement and impact of the disease.Successful early diagnosis and treatment will require the development of new agents.In this sense,boroncontaining compounds have been reported as agents with the ability to reduce glycemia and lipidemia.They have also been used for labeling and measuring carbohydrates and other molecules linked to the initial stages of diabetes and its progression.In addition,certain boron compounds bind to molecules related to diabetes development and their biological activity in the regulation of elevated glycemia.Finally,it should be noted that some boron compounds appear to exert beneficial effects on diabetes complications such as accelerating wound healing while ameliorating pain in diabetic patients. 展开更多
关键词 BORON Carbohydrates Metabolism DIABETES Boronodipyrromethene
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Humic Acid Effects on Reducing Corn Leaf Burn Caused by Foliar Spray of Urea-Ammonium Nitrate at Different Humic Acid/Urea-Ammonium Nitrate Ratios
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作者 Xinhua Yin 《Open Journal of Soil Science》 2024年第3期180-189,共10页
Technologies for reducing corn leaf burn caused by foliar spray of urea-ammonium nitrate (UAN) during the early growing season are limited. A field experiment was carried out to evaluate the effects of humic acid on c... Technologies for reducing corn leaf burn caused by foliar spray of urea-ammonium nitrate (UAN) during the early growing season are limited. A field experiment was carried out to evaluate the effects of humic acid on corn leaf burn caused by foliar spray of undiluted UAN solution on corn canopy at Jackson, TN in 2018. Thirteen treatments of the mixtures of UAN and humic acid were evaluated at V6 of corn with different UAN application rates and different UAN/humic acid ratios. Leaf burn during 1 2, 3, 4, 5, 6, 7, and 14 days after UAN foliar spray significantly differed between with or without humic acid addition. The addition of humic acid to UAN significantly reduced leaf burn at each UAN application rate (15, 25, and 35 gal/acre). The reduction of leaf burn was enhanced as the humic acid/UAN ratio went up from 10% to 30%. Leaf burn due to foliar application of UAN became severer with higher UAN rates. The linear regression of leaf burn 14 days after application with humic acid/UAN ratio was highly significant and negative. However, the linear regression of leaf burn 14 days after application with the UAN application rate was highly significant and positive. In conclusion, adding humic acid to foliar-applied UAN is beneficial for reducing corn leaf burn during the early growing season. 展开更多
关键词 Humic Acid Urea-Ammonium Nitrate CORN Leaf Burn N rate Ratio
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Processing effects on the magnetic and mechanical properties of FeCoNiAl_(0.2)Si_(0.2) high entropy alloy 被引量:13
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作者 Ting-ting Zuo Song-bo Ren +1 位作者 Peter K. Liaw Yong Zhang 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2013年第6期549-555,共7页
High entropy alloys with the composition of FeCoNiA10.2Si0.2 were prepared by arc melting and induction melting, denoted by A1 and A2, respectively. The samples prepared by these two techniques have a face-centered cu... High entropy alloys with the composition of FeCoNiA10.2Si0.2 were prepared by arc melting and induction melting, denoted by A1 and A2, respectively. The samples prepared by these two techniques have a face-centered cubic (FCC) phase structure and a typical dendrite morphology. The tensile yield strength and maximum strength of A2 samples are about 280 and 632 MPa, respectively. Moreover~ the elongation can reach 41.7%. These two alloys prepared by the different methods possess the similar magnetic properties. The saturation magnetization and coercivity can reach 1.151 T and 1400 A/m for A1 samples and 1.015 T and 1431 A/m for A2 samples, respectively. Phases in A2 samples do not change, which are heat treated at different temperatures, then quenched in water. Only the sample, which is heat treated at 600~C for 3 h and then furnace cooled, has a new phase precipitated. Besides, the coercivity decreases obviously at this temperature. Cold rolling and the subsequent heat treatment cannot improve the magnetic properties effectively. However, cold rolling plays an important role in improving the strength. 展开更多
关键词 high entropy alloys magnetic properties mechanical properties heat treatment
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Influence of Collective Boulder Array on the Surrounding Time-averaged and Turbulent Flow Fields 被引量:2
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作者 Achilleas G.TSAKIRIS A.N.Thanos PAPANICOLAOU +1 位作者 Seyed M.HAJIMIRZAIE James H.J.BUCHHOLZ 《Journal of Mountain Science》 SCIE CSCD 2014年第6期1420-1428,共9页
Arrays of large immobile boulders,which are often encountered in steep mountain streams,affect the timing and magnitude of sediment transport events through their interactions with the approach flow.Despite their impo... Arrays of large immobile boulders,which are often encountered in steep mountain streams,affect the timing and magnitude of sediment transport events through their interactions with the approach flow.Despite their importance in the quantification of the bedload rate,the collective influence of a boulder array on the approach timeaveraged and turbulent flow field has to date been overlooked.The overarching objective is,thus,to assess the collective effects of a boulder array on the time-averaged and turbulent flow fields surrounding an individual boulder within the array,placing particular emphasis on highlighting the bed shear stress spatial variability.The objective of this study is pursued by resolving and comparing the timeaveraged and turbulent flow fields developing around a boulder,with and without an array of isolated boulders being present.The results show that the effects of an individual boulder on the time-averaged streamwise velocity and turbulence intensity were limited to the boulder's immediate vicinity in the streamwise(x/d c < 2-3) and vertical(z/d c < 1) directions.Outside of the boulder's immediate vicinity,the time-averaged streamwise velocity was found to be globally decelerated.This global deceleration was attributed to the form drag generated collectively by the boulder array.More importantly,the boulder array reduced the applied shear stress exerted on theindividual boulders found within the array,by absorbing a portion of the total applied shear.Furthermore,the array was found to have a "homogenizing" effect on the near-bed turbulence thus significantly reducing the turbulence intensity in the near-bed region.The findings of this study suggest that the collective boulder array bears a portion of the total applied bed shear stress as form drag,hence reducing the available bed shear stress for transporting incoming mobile sediment.Thus,the effects of the boulder array should not be ignored in sediment transport predictions.These effects are encapsulated in this study by Equation(6). 展开更多
关键词 时间平均 集体效应 湍流流场 剪切应力 湍流强度 形状阻力 平均流 空间变异
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Extending the Economic Life of the Ogallala Aquifer with Water Conservation Policies in the Texas Panhandle 被引量:1
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作者 Lal K. Almas Bridget L. Guerrero +3 位作者 David G. Lust Hina Fatima Rachna Tewari Robert Taylor 《Journal of Water Resource and Protection》 2017年第3期255-270,共16页
The continued decline in the availability of water from the Ogallala Aquifer in the Texas Panhandle has led to an increased interest in conservation policies designed to extend the life of the aquifer and sustain rura... The continued decline in the availability of water from the Ogallala Aquifer in the Texas Panhandle has led to an increased interest in conservation policies designed to extend the life of the aquifer and sustain rural economies. Four counties were chosen for evaluation. This study evaluates the effectiveness of five policies in terms of changes in the saturated thickness, crop mix, water use per acre, and the net present value of farm profits over a 60-year planning horizon. The dynamic optimization models were developed using GAMS for the baseline as well as one for all five of the policy alternatives for each county. Results indicate that the policy scenarios of biotechnology adoption and a water use restriction will conserve the most water among the policies analyzed. In terms of economic returns, the biotechnology adoption policy by far provides the greatest benefit to producers due to yield increases that are estimated with current annual growth rates in new seed varieties. The water use restriction policy, on the other hand, has the lowest net present value of returns, indicating that conservation is accompanied with significant costs to producers. The irrigation adoption technology scenario is the next best policy in terms of net present value of returns (following biotechnology);however, it ranks last in terms of reducing aquifer depletion. It is important to note that while the models do not perfectly predict the factors being evaluated, it is the basis for comparison between the policy scenarios which are important. These comparisons will aid policy makers in determining the most effective strategy to conserve water while simultaneously considering the economic costs to producers. In addition, the results of this study can be applied to other areas facing similar conditions, either currently or in the future, throughout the Texas Panhandle. 展开更多
关键词 GROUNDWATER Conservation IRRIGATED Agriculture Ogallala AQUIFER Texas PANHANDLE Water Management Policy
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Same day discharge after structural heart disease interventions in the era of the coronavirus-19 pandemic and beyond 被引量:1
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作者 Abdulaziz A Asbeutah Muhammad Junaid +4 位作者 Fatima Hassan Jesus Avila Vega Nephertiti Efeovbokhan Rami N Khouzam Uzoma N Ibebuogu 《World Journal of Cardiology》 2022年第5期271-281,共11页
With recent advancements in imaging modalities and techniques and increased recognition of the long-term impact of several structural heart disease interventions,the number of procedures has significantly increased.Wi... With recent advancements in imaging modalities and techniques and increased recognition of the long-term impact of several structural heart disease interventions,the number of procedures has significantly increased.With the increase in procedures,also comes an increase in cost.In view of this,efficient and cost-effective methods to facilitate and manage structural heart disease interventions are a necessity.Same-day discharge(SDD)after invasive cardiac procedures improves resource utilization and patient satisfaction.SDD in appropriately selected patients has become the standard of care for some invasive cardiac procedures such as percutaneous coronary interventions.This is not the case for the majority of structural heart procedures.With the coronavirus disease 2019 pandemic,safely reducing the duration of time spent within the hospital to prevent unnecessary exposure to pathogens has become a priority.In light of this,it is prudent to assess the feasibility of SDD in several structural heart procedures.In this review we highlight the feasibility of SDD in a carefully selected population,by reviewing and summarizing studies on SDD among patients undergoing left atrial appendage occlusion,patent foramen ovale/atrial septal defect closure,Mitra-clip,and trans-catheter aortic valve replacement procedures. 展开更多
关键词 Mitra-clip Transcatheter aortic valve replacement Same-day discharge Atrial septal defect CORONAVIRUS
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Temperature Sensitivity of Nitrogen Dynamics of Agricultural Soils of the United States 被引量:1
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作者 Amitava Chatterjee Alexsandro Felipe de Jesus +6 位作者 Diksha Goyal Sailesh Sigdel Larry J. Cihacek Bhupinder S. Farmaha Sindhu Jagadamma Lakesh Sharma Daniel S. Long 《Open Journal of Soil Science》 2020年第7期298-305,共8页
Soil temperature controls gaseous nitrogen losses through nitrous oxide (N<sub>2</sub>O) and ammonia (NH<sub>3</sub>) fluxes. Eight surface soils from agricultural fields across the United Stat... Soil temperature controls gaseous nitrogen losses through nitrous oxide (N<sub>2</sub>O) and ammonia (NH<sub>3</sub>) fluxes. Eight surface soils from agricultural fields across the United States were incubated at 10<span style="white-space:nowrap;">°</span>C, 20<span style="white-space:nowrap;">°</span>C, and 30<span style="white-space:nowrap;">°</span>C, and N<sub>2</sub>O and NH<sub>3</sub> flux were measured twice a week for 91 and 47 d, respectively. Changes in cumulative N<sub>2</sub>O and NH<sub>3</sub> flux and net N mineralization at three temperatures were fitted to calculate Q<sub>10</sub> using the Arrhenius equation. For the majority of soils, Q<sub>10</sub> values for the N<sub>2</sub>O loss ranged between 0.23 and 2.14, except for Blackville, North Carolina (11.4) and Jackson, Tennessee (10.1). For NH<sub>3</sub> flux, Q<sub>10</sub> values ranged from 0.63 (Frenchville, Maine) to 1.24 (North Bend, Nebraska). Net soil N mineralization-Q<sub>10</sub> ranged from 0.96 to 1.00. Distribution of soil organic carbon and total soil N can explain the variability of Q<sub>10</sub> for N<sub>2</sub>O loss. Understanding the Q<sub>10</sub> variability of soil N dynamics will help us to predict the N loss. 展开更多
关键词 Arrhenius Equation Soil Organic Carbon Inorganic Nitrogen Gaseous Losses of Nitrogen
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Assessing adaptability and response of vegetation to glacier recession in the afro-alpine moorland terrestrial ecosystem of Rwenzori Mountains
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作者 Tonny J.OYANA Bob R.NAKILEZA 《Journal of Mountain Science》 SCIE CSCD 2016年第9期1584-1597,共14页
The objective of this study was to explore vegetation adaptability in a changing afro-alpine moorland terrestrial ecosystem on Mt. Rwenzori and to determine whether there were any links with response of vegetation to ... The objective of this study was to explore vegetation adaptability in a changing afro-alpine moorland terrestrial ecosystem on Mt. Rwenzori and to determine whether there were any links with response of vegetation to glacier recession. We analyzed the composition and distribution of plant species in relation to soils, geomorphic processes, and landscape positions in the Alpine zone. To accomplish this objective, archival data sources and published reports for this ecosystem were reviewed. A field trip was conducted in 2010 to study in detail seven vegetation sampling plots that were systematically selected using GIS maps and a nested-quadrat sampling design framework along an altitudinal gradient in the lower and upper alpine zones. Using these sampling plots, 105 vegetation and 13 soil samples were assessed in the alpine zone. Soil samples were taken for laboratory testing and analysis. The results show statistically significant differences in p H, OM, N, P, Ca, Mg, and K pools between soils samples drawn from the lower and upper alpine sites(p < 0.0033). Furthermore, we observed a significant vegetation formation with numerous structural forms, but there was a limited diversity of species. The mostsignificant forms included Alchemilla carpets, Bogs, Dendrosenecio woodland, and Scree slopes. The lower alpine area(3500–3900 masl) had a more diverse plant species than other areas, especially Alchemilla argyrophylla and Dendrosenecio adnivalis species that were evident due to well-drained deeper soils. The Alchemilla subnivalis were evident at a higher altitude of above 4000 masl. Shifts in the Astareceae(e.g. Senecio species) were particularly prominent even on recently deglaciated areas. The spatial variations of species distribution, structure, and composition suggest there are serious implications in terms of ecosystem adaptability, resilience, and stability that require further evaluation. 展开更多
关键词 陆地生态系统 高山区 适应性 植被 沼泽 评估 冰川 非洲
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The Effects of Protruding Rock Boulders in Regulating Sediment Intrusion within the Hyporheic Zone of Mountain Streams
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作者 Dimitrios DERMISIS A.N.Thanos PAPANICOLAOU 《Journal of Mountain Science》 SCIE CSCD 2014年第6期1466-1477,共12页
Excessive sedimentation in mountain stream ecosystems is a critical environmental problem due to the clogging of streambeds by sediment particles within the hyporheic zone,with detrimental effects on fish spawning hab... Excessive sedimentation in mountain stream ecosystems is a critical environmental problem due to the clogging of streambeds by sediment particles within the hyporheic zone,with detrimental effects on fish spawning habitat.In this research,the effects of an array of boulders in regulating the intrusion of incoming sand within a gravel substrate were evaluated by performing detailed experiments in a laboratory flume.A unique experimental setup and two different sampling techniques were utilized for measuring the infiltrated sand within the gravel bed under two bed shear stress conditions(moderate vs.high).For comparison purposes,experiments were performed without and with the presence of partially submerged to the flow(protruding) boulders,which is typical for the average flow conditions found in mountain streams.Results indicated that sand infiltrated primarily in the upper part of the gravel bed creating a surface seal which hindered the penetration of sand particles deeper into the bed.An exponential decrease of the amount of the infiltrated sand within the hyporheic zone was observed in all experiments regardless of the presence of boulders.However,the presence of boulders promoted sediment intrusion of sand particles especially for the moderate applied bed shear stress condition,since the total amount of the infiltrated sand was found to be on average 44% greater whenboulders were present.The findings from this study can provide additional insight regarding the role of boulders on promoting downwelling of flow and sediment within the gravel substrate with potential effects on fish habitat. 展开更多
关键词 泥沙颗粒 山区河流 流带 入侵 岩石 河流生态系统 平均流量 实验室
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Roles of vitamin A in the regulation of fatty acid synthesis
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作者 Fu-Chen Yang Feng Xu +1 位作者 Tian-Nan Wang Guo-Xun Chen 《World Journal of Clinical Cases》 SCIE 2021年第18期4506-4519,共14页
Dietary macronutrients and micronutrients play important roles in human health.On the other hand,the excessive energy derived from food is stored in the form of triacylglycerol.A variety of dietary and hormonal factor... Dietary macronutrients and micronutrients play important roles in human health.On the other hand,the excessive energy derived from food is stored in the form of triacylglycerol.A variety of dietary and hormonal factors affect this process through the regulation of the activities and expression levels of those key player enzymes involved in fatty acid biosynthesis such as acetyl-CoA carboxylase,fatty acid synthase,fatty acid elongases,and desaturases.As a micronutrient,vitamin A is essential for the health of humans.Recently,vitamin A has been shown to play a role in the regulation of glucose and lipid metabolism.This review summarizes recent research progresses about the roles of vitamin A in fatty acid synthesis.It focuses on the effects of vitamin A on the activities and expression levels of mRNA and proteins of key enzymes for fatty acid synthesis in vitro and in vivo.It appears that vitamin A status and its signaling pathway regulate the expression levels of enzymes involved in fatty acid synthesis.Future research directions are also discussed. 展开更多
关键词 Vitamin A Acetyl-CoA carboxylase Fatty acid synthase Fatty acid elongase Stearoyl-CoA desaturase Fatty acid synthesis
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Soybean Seed Protein, Oil, Fatty Acids, and Isoflavones Altered by Potassium Fertilizer Rates in the Midsouth
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作者 Nacer Bellaloui Xinhua Yin +3 位作者 Alemu Mengistu Angela M. McClure Don D. Tyler Krishna N. Reddy 《American Journal of Plant Sciences》 2013年第5期976-988,共13页
Previous research has shown that the effect of potassium fertilizer on soybean ([Glycine max (L.) Merr.] seed composition (protein, oil, fatty acids, and isoflavones) is still largely unknown. Therefore, the objective... Previous research has shown that the effect of potassium fertilizer on soybean ([Glycine max (L.) Merr.] seed composition (protein, oil, fatty acids, and isoflavones) is still largely unknown. Therefore, the objective of this research was to investigate the effects of potassium application on seed protein, oil, fatty acids, and isoflavones under Midsouth environmental conditions. A three-year experiment was conducted in two locations (Milan, TN and Jackson, TN). Potassium (K) rates were applied in the form of K2O at a rate of 0 (Control, C), 45 (T1), 90 (T2), 134 (T3), and 179 (T4) kg·ha-1 in a randomized complete block design. The results showed that increasing the K application rate did not result in consistent effects on yield. However, increasing K application rate did increase protein, oleic acid, and individual and total isoflavone concentrations at both locations in 2008 and 2009. In Jackson in 2010, the increase of K rate did not change oleic acid, but resulted in an increase in glycitein and genistein isoflavone concentrations. In 2010, increasing K application rate increased protein concentrations, decreased individual and total isoflavones, and did not change oleic acid concentration at Milan. At the highest rate of K, 179 kg·ha-1, yield and some seed composition constituents were negatively impacted. Generally, K concentration in leaves at V5, R1, R3, and seed at harvest maturity stage (R8) increased with the increase of K rate applications. The research demonstrated that K application can alter seed composition, but this alteration depended on location, environmental stress factors, mainly heat and drought, K level in soil, and K application rate. Higher rates of K application may negatively impact seed composition constituents. 展开更多
关键词 FATTY Acids ISOFLAVONES OIL Oleic Acid POTASSIUM FERTILIZER Protein Seed Composition
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