Natural Science最新文献_第10页

Motor Control Network Effective Connectivity in Regulating Muscle Force Output 运动控制网络在调节肌肉力量输出中的有效连接

Natural Science Pub Date : 2021-02-19 DOI: 10.4236/NS.2021.132002

S. Saleh, Zhiguo Jiang, G. Yue

{"title":"Motor Control Network Effective Connectivity in Regulating Muscle Force Output","authors":"S. Saleh, Zhiguo Jiang, G. Yue","doi":"10.4236/NS.2021.132002","DOIUrl":"https://doi.org/10.4236/NS.2021.132002","url":null,"abstract":"Objective of the study: \u0000This study aimed at characterizing output features of the higher-order motor \u0000control centers (hoMCCs), including secondary (premotor cortex [Pre] and \u0000supplementary motor area [SMA]) and association (prefrontal cortex [PFC]) motor \u0000regions to the primary motor cortex (M1) during graded force tasks. It is well \u0000known that one of the major roles of the primary motor cortex (M1) is \u0000controlling motor output such as muscle force. However, it is unclear how the \u0000hoMCCs interact with M1 in regulating voluntary muscle contractions. Methods: \u0000fMRI data was acquired during graded force tasks and fMRI-based effective \u0000connectivity (EC) and muscle force analyses were performed to study the \u0000relationship between hoMCCs-M1 effective connectivity and voluntarily exerted \u0000handgrip force. Results: The results show that there is a consistent \u0000information flow from the hoMCCs to M1 under all force conditions, suggesting a \u0000hierarchical control mechanism in the brain in regulating voluntary muscle \u0000force. Only the premotor cortex exhibited a significant role in mediating the \u0000level of force production through its EC with M1 but that role diminished when \u0000the exerted force was high, suggesting perhaps a ceiling and/or fatigue effect \u0000on the EC. A flip in the direction of EC from the primary sensory cortex (S1) to \u0000the hoMCCs (PFC, SMA, and Pre) at lower force levels while at higher forces EC \u0000was observed from the hoMCCs to S1. Conclusion: The hoMCCs regulate M1 output \u0000to produce desired voluntary muscle force. Only the Pre-to-M1 connectivity \u0000strength directly correlates with the force level especially from low to \u0000moderate levels. The hoMCCs are involved in modulating higher force production \u0000likely by strengthening M1 output and downgrading inhibition from \u0000S1 to M1.","PeriodicalId":19083,"journal":{"name":"Natural Science","volume":"14 1","pages":"9-17"},"PeriodicalIF":0.0,"publicationDate":"2021-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85250225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 6

Antimicrobial Properties of Copper and d-Orbital Capture 铜的抗菌性能和d轨道捕获

Natural Science Pub Date : 2021-02-19 DOI: 10.4236/NS.2021.132004

P. Love

{"title":"Antimicrobial Properties of Copper and d-Orbital Capture","authors":"P. Love","doi":"10.4236/NS.2021.132004","DOIUrl":"https://doi.org/10.4236/NS.2021.132004","url":null,"abstract":"The \u0000purpose of this note is to stimulate interest in measuring and characterizing \u0000the emitted ultraviolet frequencies in antimicrobial copper materials. Antimicrobial \u0000sanitizing materials are urgently needed to limit the spread of COVID-19 virus. \u0000In the current pandemic, ultraviolet radiation is often used for sterilization. \u0000It is shown that 3 d-orbital \u0000capture in copper can result in radiation generated by copper materials. Since \u0000ultraviolet radiation is known to be effective in antimicrobial sterilization, \u0000it is logical to assume that the radiation formed by copper occurs in the \u0000ultraviolet region. Electron transitions in 3 d-orbital capture are expected to \u0000occur in this region. A description of the 3 d-orbital capture process, and the \u0000origin of the associated frequency, is given. It is shown that for Group 1B \u0000elements the strength of electron affinity in the d-orbital capture process \u0000increases with increasing Periodic Table period number, n. This is the opposite \u0000of other electron affinity properties for atoms that decrease wth an increase \u0000in n. A brief discussion of the relationship of d-orbital capture to the \u0000chemical inertness of gold is given. The same type of d-orbital capture process \u0000that occurs in antimicrobial copper occurs in high temperature superconducting \u0000cuprates.","PeriodicalId":19083,"journal":{"name":"Natural Science","volume":"1 1","pages":"21-25"},"PeriodicalIF":0.0,"publicationDate":"2021-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91273657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The Dependence of N-Malonyltryptophan Formation in Plants on Water Deficit (Review) 植物n -丙二酰色氨酸形成对水分亏缺的依赖性

Natural Science Pub Date : 2021-02-19 DOI: 10.4236/NS.2021.132005

K. Z. Gamburg

{"title":"The Dependence of N-Malonyltryptophan Formation in Plants on Water Deficit (Review)","authors":"K. Z. Gamburg","doi":"10.4236/NS.2021.132005","DOIUrl":"https://doi.org/10.4236/NS.2021.132005","url":null,"abstract":"Drought stress in plants is accompanied by several metabolic changes. One of them is the appearance of N-malonyltryptophan (MT) during leaf wilting of many species, but there is a significant number of plant species in which the appearance of MT did not occur. Plants of some species were able to synthesize also N-acetyltryptophan (AT). Excised tomato leaves incubated with D-amino acids (including D-Trp) transform them into malonyl- and acetyl-derivatives even without water deficit. However, MT which appeared during water deficit has been shown to contain L-Trp. Amino acid—1-amino-cyclopropane-1-carboxylic acid (ACC) is also malonylated during water deficit, but other L-amino acids were not malonylated. N-malonyl transferases specific for Trp and ACC have been found in several plants. The existence of N-malonyltransferase specific to L-Trp and appeared during water deficit in plants forming MT is supposed, but clear experimental proof has not been obtained yet. Plants can transform MT applied exogenously into Trp and further to indole-3-acetic acid (IAA). But no evidence has been appeared up to now that endogenous MT may be a source of IAA. It is unknown till now why it is necessary for plants of many species to malonylate only Trp during water deficit. How MT metabolized in animals and if it affects them is also unknown. The necessity to use molecular-genetic approaches for the elucidation of the physiological significance of MT formation during water deficit is underlined.","PeriodicalId":19083,"journal":{"name":"Natural Science","volume":"34 1","pages":"26-41"},"PeriodicalIF":0.0,"publicationDate":"2021-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77204761","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Particle Motion in Surface Gravity Waves 表面重力波中的粒子运动

Natural Science Pub Date : 2021-02-19 DOI: 10.4236/NS.2021.132003

K. Kenyon

引用次数: 0

Relativistic Quantitative Determination of the “Mysterious” Differences in the Hubble Constant 哈勃常数“神秘”差异的相对论定量测定

Natural Science Pub Date : 2021-01-20 DOI: 10.4236/NS.2021.131001

Ernst Karl Kunst

引用次数: 0

Achieving Sustainability 实现可持续发展

Natural Science Pub Date : 2021-01-01 DOI: 10.4236/ns.2021.137023

M. Platts

引用次数: 5

Review of Dye-Sensitized Solar Cell (DSSCs) Development 染料敏化太阳能电池(DSSCs)的研究进展

Natural Science Pub Date : 2021-01-01 DOI: 10.4236/ns.2021.1312043

Okoye Ikechukwu Francis, A. Ikenna

{"title":"Review of Dye-Sensitized Solar Cell (DSSCs) Development","authors":"Okoye Ikechukwu Francis, A. Ikenna","doi":"10.4236/ns.2021.1312043","DOIUrl":"https://doi.org/10.4236/ns.2021.1312043","url":null,"abstract":"Energy consumption is increasing yearly all over the world due to the increase in population and demand of energy. The world largely depends on a hydroelectric energy supply, thermal electric energy supply which is all non-renewable energy resources. Nevertheless, non-re-newable energy resources are rapidly decreasing per year due to increasing rate of energy consumption. The quest for the discovery of another abundant resource of energy has at-tracted many scientists into development of renewable energy technologies like photovoltaic energy which are the technology that convert solar radiation into electricity. For the past several years, different photovoltaic devices like inorganic, organic, and hybrid solar cells have been invented using different methods for different application purposes. Moreover, high conversion efficiency of silicon solar cells, the high cost of module and complicated production processes involved in the production restricted commercialization of photovoltaic solar cells as a means of electricity supply. Among all organic solar cells, Dye-Sensitized Solar Cells (DSSCs) are the most efficient, low cost and easily implemented technology. This review paper focuses on clarifying the technological meaning of the structure of DSSCs, Various types of DSSCs materials, working electrode and working mechanism of DSSC, transparent and conductive substrate, nanocrystalline semiconductor film electrode, pho-tosensisitizer (dye), electrolyte, carbon layer electrode, zinc oxide (ZnO) layer, zirconium dioxide (ZrO 2 ) layer, benefits of DSSCs and application, the efficiency and challenges for research and development of DSSCs to upgrade the current efficiency.","PeriodicalId":19083,"journal":{"name":"Natural Science","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85262667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 15

Wind Wave Growth 风浪生长

Natural Science Pub Date : 2021-01-01 DOI: 10.4236/NS.2021.135013

K. Kenyon

引用次数: 2

Antlers Are Shaped as Elements of Concave Surfaces that Reflect and Concentrate Incoming Sounds 鹿角的形状像凹面的元素，反射和集中传入的声音

Natural Science Pub Date : 2021-01-01 DOI: 10.4236/ns.2021.1311039

M. Rossetto

引用次数: 1

Reasons of Vaccine Hesitancy among Pakistanis with Available COVID-19 Vaccine: The Next Challenge in the Fight against COVID-19 拥有COVID-19疫苗的巴基斯坦人对疫苗犹豫的原因:抗击COVID-19的下一个挑战

Natural Science Pub Date : 2021-01-01 DOI: 10.4236/NS.2021.136018

W. Rizwan, Muhammad Nasir Rana, M. Bukhari, A. Mushtaq, M. Sadiq

{"title":"Reasons of Vaccine Hesitancy among Pakistanis with Available COVID-19 Vaccine: The Next Challenge in the Fight against COVID-19","authors":"W. Rizwan, Muhammad Nasir Rana, M. Bukhari, A. Mushtaq, M. Sadiq","doi":"10.4236/NS.2021.136018","DOIUrl":"https://doi.org/10.4236/NS.2021.136018","url":null,"abstract":"The government of Pakistan started vaccination campaign for the frontline healthcare pro-viders, as they are more likely to be exposed to COVID-19 patients. In the next step, it ex-tended the free vaccination campaign to include people above 60 and 50 years of age re-spectively. The drive is now open to all citizens >18 years of age. There is a significant re-luctance to get vaccinated even though the government has provided it free of cost. The project uses self-reporting method to assess reasons of vaccine hesitancy among Pakistanis and possible solutions to overcome this problem. Concern for serious side effects was the most common issue 154 (48.42%) reported among all groups of people, including the healthcare workers. The major sources of COVID-19 related information were television 117 (36.8%) and healthcare professionals 105 (33%). The participants reported that they can be convinced to get vaccinated if more published data related to vaccine efficacy and safety is available 118 (37.1%), they observe no side effect among vaccine recipients 90 (28.3%) or higher government officials get the same vaccine 39 (12.3%). Vigorous analysis and publication of data generated is paramount to increase the percentage of people being vaccinated. The healthcare professionals should share evidence-based knowledge related to vaccine efficacy and safety through television and social media to increase acceptance rates and hence, decrease mortality and morbidity from COVID-19 in Pakistan.","PeriodicalId":19083,"journal":{"name":"Natural Science","volume":"30 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87225077","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 12