期刊文献+
共找到2,492篇文章
< 1 2 125 >
每页显示 20 50 100
Designing a Comprehensive Data Governance Maturity Model for Kenya Ministry of Defence
1
作者 Gilly Gitahi Gathogo Simon Maina Karume Josphat Karani 《Journal of Information Security》 2025年第1期44-69,共26页
The study aimed to develop a customized Data Governance Maturity Model (DGMM) for the Ministry of Defence (MoD) in Kenya to address data governance challenges in military settings. Current frameworks lack specific req... The study aimed to develop a customized Data Governance Maturity Model (DGMM) for the Ministry of Defence (MoD) in Kenya to address data governance challenges in military settings. Current frameworks lack specific requirements for the defence industry. The model uses Key Performance Indicators (KPIs) to enhance data governance procedures. Design Science Research guided the study, using qualitative and quantitative methods to gather data from MoD personnel. Major deficiencies were found in data integration, quality control, and adherence to data security regulations. The DGMM helps the MOD improve personnel, procedures, technology, and organizational elements related to data management. The model was tested against ISO/IEC 38500 and recommended for use in other government sectors with similar data governance issues. The DGMM has the potential to enhance data management efficiency, security, and compliance in the MOD and guide further research in military data governance. 展开更多
关键词 Data Governance Maturity Model Maturity Index Kenya Ministry of defence Key Performance Indicators Data Security Regulations
在线阅读 下载PDF
Post-Traumatic Stress Disorder among Defence and Security Forces in Northern Benin (2023)
2
作者 Ireti Nethania Elie Ataigba Guy Gérard Aza Gnandji +6 位作者 David Sinet Koivogui Dalmace Fauste Adjaho Eurydice Elvire Djossou Anselme Djidonou Francis Tognon Tchegnonsi Prosper Gandaho Josiane Ezin Houngbe 《Open Journal of Psychiatry》 2024年第2期142-161,共20页
Introduction: Post-traumatic stress disorder (PTSD) is defined as “actual exposure to death or the threat of death, serious injury or sexual violence”, either directly or indirectly, resulting in a symptomatic proce... Introduction: Post-traumatic stress disorder (PTSD) is defined as “actual exposure to death or the threat of death, serious injury or sexual violence”, either directly or indirectly, resulting in a symptomatic procession of repetition, avoidance, neurovegetative hyperactivity and individualized symptoms, with or without negative cognitive and mood changes. It therefore goes without saying that the defence and security forces constitute a high-risk population in need of attention. Objective: To study post-traumatic stress disorder in defence and security forces in the city of Parakou in 2023. Methods: Descriptive cross-sectional study conducted from December 2022 to July 2023. The study population consisted of active military, republican police and firefighters in the city of Parakou in 2023. Non-proportional stratified sampling was used, given the inaccessibility of the source population size for national security reasons. Post-traumatic stress disorder was assessed using the “post-traumatic stress disorder checklist-5 (PCLS-5) scale. Results: A total of 305 subjects participated in the survey. Males dominated 90.2%. The most represented corps was the Republican Police (41.6%), most of whom were non-commissioned officers (46.6%). The majority count between 11 and 20 years of service (48.9%), with 2 to 5 missions completed (67.5%). The calculated prevalence of post-traumatic stress disorder was 11.8%, based on the post-traumatic stress disorder checklist-5 (PCL-5). Of the 36 respondents with post-traumatic stress disorder, 20 (55.6%) had experienced an armed attack, 25 (69.4%) had witnessed a violent death, 18 (50.0%) had witnessed the agony of a colleague, 15 (41.7%) had been exposed to a fire or explosion, while 26 (72.2%) had been traumatized by physical and/or verbal aggression. 5 (13.9%) had consulted a specialist psychiatrist, while 6 (16.7%) were on medication and 26 (72.2%) used sport as a means of maintaining physical and mental health. Respectively 22 (61.1%) and 21 (58.3%) had definite symptoms of anxiety and depression. Multivariate analysis revealed a significant association between post-traumatic stress disorder and the following variables: total number of children ≤ 2 (p = 0.015), comorbidities such as arterial hypertension (p = 0.007), history of hepatitis (p = 0.017), work accidents (p = 0.016), alcohol dependence (p = 0.004), domestic violence (p = 0.004), psychological violence (p = 0.017) and anxiety disorders (p Conclusion: Defence and security personnel can also be prey to post-traumatic stress disorder (PTSD), which needs to be systematically taken into account when they are subjected to trauma in the course of their duties. Mental health should be an integral part of the periodic medical check-up objectives for defence and security forces throughout the country. 展开更多
关键词 Post-Traumatic Stress Disorder FORCES defence SECURITY BENIN 2023
在线阅读 下载PDF
Security Defence Policy Selection Method Using the Incomplete Information Game Model 被引量:3
3
作者 ZHANG Hengwei YU Dingkun +2 位作者 WANG Jindong HAN Jihong WANG Na 《China Communications》 SCIE CSCD 2015年第S2期123-131,共9页
Nowadays, the network defence policy selection using game model of incomplete information ignores the type of the defender, which quantifies cost simply, resulting in unreasonable defence policies selection. Aiming at... Nowadays, the network defence policy selection using game model of incomplete information ignores the type of the defender, which quantifies cost simply, resulting in unreasonable defence policies selection. Aiming at the problem, we use Bayesian game theory to model the active defence policy selection. We take the types of both the attacker and the defender into consideration. Besides, the traditional quantization method is enhanced. Then, we calculate the equilibrium of static Bayesian game. Based on the analysis of the equilibrium, we select the optimal defence policy through the prediction for attackers' actions. The paper calculates the defence effectiveness of defence policies and provides a defence policies selection algorithm. Ultimately, we present an example to verify the effectiveness of the method and model proposed in the paper. 展开更多
关键词 GAME INCOMPLETE information POLICY SELECTION active defence
在线阅读 下载PDF
A review on lightweight materials for defence applications:Present and future developments 被引量:11
4
作者 Suchart Siengchin 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2023年第6期1-17,共17页
The defence sector is now at an advanced level,catering to the global scenario,and countries also invest heavily in research and development.Countries around the world have spent a lot of money on research and develop... The defence sector is now at an advanced level,catering to the global scenario,and countries also invest heavily in research and development.Countries around the world have spent a lot of money on research and development over the years in order to stay ahead of their competitors.Lightweight materials are critical in defence applications because they allow components to be lighter without sacrificing strength.This review provides an overview of the research related to defence applications.The book provides comprehensive details on current trends in the application of lightweight materials in defence.This review also includes historical and current perspectives on defence technologies.It discusses uses of lightweight materials such as metal matrix composites,polymer composites,ceramic matrix composites,fiber composites in defence sectors Finally,the review paper also emphasizes future military applications of lightweight materials. 展开更多
关键词 Lightweight materials defence TECHNOLOGIES DEVELOPMENTS APPLICATIONS
在线阅读 下载PDF
Recent applications of carbon-based composites in defence industry: A review 被引量:11
5
作者 M.M.Harussani S.M.Sapuan +2 位作者 Gohar Nadeem Tahrim Rafin W.Kirubaanand 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2022年第8期1281-1300,共20页
Carbon-based composites, including carbon reinforced composites and carbon-matrix composites, in defence technologies have raised a lot of attention due to its significant physical capabilities, superior thermal and m... Carbon-based composites, including carbon reinforced composites and carbon-matrix composites, in defence technologies have raised a lot of attention due to its significant physical capabilities, superior thermal and mechanical stability, and its eco-friendly nature. Carbon-based composite which incorporating with various carbonaceous materials such as coke, char, black carbon, activated carbon, carbon fibre and other carbon nanomaterials (carbon nanotubes, carbon nanofibres, graphene and graphite) are the greatest viable option for the development of advanced defence technologies. In this review article the characteristics of carbon-based materials and its composites are discussed for their distinct application in defence sectors;aeronautics, maritime, automotive, electronics, energy storage, electromagnetic interference (EMI) shielding and structures. The origin of carbonaceous materials and its production techniques were discussed. Carbon-based composites have a promising future in defence technology, particularly in chemical sensors, drug delivery agents, radar technologies, and nanocomposites due to their low cost, easy availability, flexibility in design and processing. 展开更多
关键词 Carbon materials CHAR CARBON CNT GRAPHENE Composite defence technology
在线阅读 下载PDF
Optimal Active Defence Using Dynamic Multi-Stage Signalling Game 被引量:2
6
作者 ZHANG Hengwei LI Tao +1 位作者 WANG Jindong HAN Jihong 《China Communications》 SCIE CSCD 2015年第S2期114-122,共9页
Nowadays, security defence of network uses the game theory, which mostly applies complete information game model or even the static game model. To get closer to the actual network and defend actively, we propose a net... Nowadays, security defence of network uses the game theory, which mostly applies complete information game model or even the static game model. To get closer to the actual network and defend actively, we propose a network attack-defence game model by using signalling game, which is modelled in the way of dynamic and incomplete information. We improve the traditional attack-defence strategies quantization method to meet the needs of the network signalling game model. Moreover, we give the calculation of the game equilibrium and analyse the optimal defence scheme. Finally, we analyse and verify effectiveness of the model and method through a simulation experiment. 展开更多
关键词 active defence DYNAMIC INCOMPLETE information MULTI-STAGE SIGNALLING GAME theory
在线阅读 下载PDF
Induction of defence gene expression by oligogalacturonic acid requires in-creases in both cytosolic calcium and hydrogen peroxide in Arabidopsis thaliana 被引量:4
7
作者 XiangYangHU StevenJNEILL +1 位作者 WeiMingCAI ZhangChengTANG 《Cell Research》 SCIE CAS CSCD 2004年第3期234-240,共7页
Responses to oligogalacturonic acid (OGA) were determined in transgenic Arabidopsis thaliana seedlings expressing the calcium reporter protein aequorin. OGA stimulated a rapid, substantial and transient increase in th... Responses to oligogalacturonic acid (OGA) were determined in transgenic Arabidopsis thaliana seedlings expressing the calcium reporter protein aequorin. OGA stimulated a rapid, substantial and transient increase in the concentration of cytosolic calcium ([Ca2+]cyt) that peaked after ca. 15 s. This increase was dose-dependent, saturating at ca. 50 μg Gal equiv/ml of OGA. OGA also stimulated a rapid generation of H2O2. A small, rapid increase in H2O2 content was followed by a much larger oxidative burst, with H2O2 content peaking after ca. 60 min and declining thereafter. Induction of the oxidative burst by OGA was also dose-dependent, with a maximum response again being achieved at ca. 50 μg Gal equiv/mL. Inhibitors of calcium fluxes inhibited both increases in [Ca2+]cyt and [H2O2], whereas inhibitors of NADPH oxidase blocked only the oxidative burst. OGA increased strongly the expression of the defence-related genes CHS,GST, PAL and PR-1. This induction was suppressed by inhibitors of calcium flux or NADPH oxidase, indicating that increases in both cytosolic calcium and H2O2 are required for OGA-induced gene expression. 展开更多
关键词 Arabidopsis thaliana cytosolic calcium defence gene expression hydrogen peroxide OGA.
在线阅读 下载PDF
OpenIFEM:A High Performance Modular Open-Source Software of the Immersed Finite Element Method for Fluid-Structure Interactions 被引量:3
8
作者 Jie Cheng Feimi Yu Lucy T.Zhang 《Computer Modeling in Engineering & Sciences》 SCIE EI 2019年第4期91-124,共34页
We present a high performance modularly-built open-source software-OpenIFEM.OpenIFEM is a C++implementation of the modified immersed finite element method(mIFEM)to solve fluid-structure interaction(FSI)problems.This s... We present a high performance modularly-built open-source software-OpenIFEM.OpenIFEM is a C++implementation of the modified immersed finite element method(mIFEM)to solve fluid-structure interaction(FSI)problems.This software is modularly built to perform multiple tasks including fluid dynamics(incompressible and slightly compressible fluid models),linear and nonlinear solid mechanics,and fully coupled fluid-structure interactions.Most of open-source software packages are restricted to certain discretization methods;some are under-tested,under-documented,and lack modularity as well as extensibility.OpenIFEM is designed and built to include a set of generic classes for users to adapt so that any fluid and solid solvers can be coupled through the FSI algorithm.In addition,the package utilizes well-developed and tested libraries.It also comes with standard test cases that serve as software and algorithm validation.The software can be built on cross-platform,i.e.,Linux,Windows,and Mac OS,using CMake.Efficient parallelization is also implemented for high-performance computing for large-sized problems.OpenIFEM is documented using Doxygen and publicly available to download on GitHub.It is expected to benefit the future development of FSI algorithms and be applied to a variety of FSI applications. 展开更多
关键词 Immersed FINITE element method open-source PARALLELIZATION fluid-structure interaction adaptive MESH REFINEMENT
在线阅读 下载PDF
The Arabidopsis homologs of CCR4-associated factor 1 show mRNA deadenylation activity and play a role in plant defence responses 被引量:8
9
作者 Wenxing Liang Changbao Li +5 位作者 Fang Liu Hongling Jiang Shuyu Li Jiaqiang Sun Xiaoyan Wu Chuanyou Li 《Cell Research》 SCIE CAS CSCD 2009年第3期307-316,共10页
Messenger RNA (mRNA) turnover in eukaryotic cells begins with shortening of the poly (A) tail at the 3' end, a process called deadenylation. In yeast, the deadenylation reaction is predominantly mediated by CCR4 ... Messenger RNA (mRNA) turnover in eukaryotic cells begins with shortening of the poly (A) tail at the 3' end, a process called deadenylation. In yeast, the deadenylation reaction is predominantly mediated by CCR4 and CCR4- associated factor 1 (CAF1), two components of the well-characterised protein complex named CCR4-NOT. We report here that AtCAF1a and AtCAF1b, putative Arabidopsis homologs of the yeast CAF1 gene, partially complement the growth defect of the yeast call mutant in the presence of caffeine or at high temperatures. The expression of At-CAF1a and AtCAFlb is induced by multiple stress-related hormones and stimuli. Both AtCAF1a and AtCAFlb show deadenylation activity in vitro and point mutations in the predicted active sites disrupt this activity. T-DNA insertion mutants disrupting the expression of AtCAF1a and/or AtCAF1b are defective in deadenylation of stress-related mRNAs, indicating that the two AtCAF1 proteins are involved in regulated mRNA deadenylation in vivo. Interestingly, the single and double mutants of AtCAF1a and AtCAFlb show reduced expression of pathogenesis-related (PR) genes PR1 and PR2 and are more susceptible to Pseudomonas syringae pv tomato DC3000 (Pst DC3000) infection, whereas transgenic plants over-expressing AtCAFla show elevated expression of PR1 and PR2 and increased resis-tance to the same pathogen. Our results suggest roles of the AtCAF1 proteins in regulated mRNA deadenylation and defence responses to pathogen infections. 展开更多
关键词 CCR4-associated factor 1 (CAF1) mRNA deadenylation poly (A) tails defence response Arabidopsis thaliana
在线阅读 下载PDF
Effects of Motivation and Demography on the Quantitative Plausibility of the Trojan Horse Defence Against Possession of Child Pornography 被引量:1
10
作者 Richard E Overill Jantje A M Silomon +1 位作者 Kam-Pui Chow Hayson Tse 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2014年第6期9-15,共7页
The Enhanced Complexity Model( ECM) developed previously has been further extended to produce a Motivationally Enhanced Complexity Model( MECM) which enables the degree of motivation,capability and opportunity of a hy... The Enhanced Complexity Model( ECM) developed previously has been further extended to produce a Motivationally Enhanced Complexity Model( MECM) which enables the degree of motivation,capability and opportunity of a hypothetical Trojan Horse author to be included in quantifying the relative plausibility of competing explanations for the existence of uncontested digital evidence.This new model has been applied to the case of the Trojan Horse defence( THD) against the possession of child pornography.Our results demonstrate that the THD in this case cannot be plausibly sustained unless it can be shown that an ‘off-theshelf'( OTS) Trojan Horse for this task is available and it is not detectable by the target computer,at the material time. 展开更多
关键词 Trojan Horse defence child pornography digital forensic evidence complexity quantitative plausibility metrics posterior odds
在线阅读 下载PDF
Open-Source Codes of Topology Optimization: A Summary for Beginners to Start Their Research 被引量:2
11
作者 Yingjun Wang Xinqing Li +1 位作者 Kai Long Peng Wei 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第10期1-34,共34页
Topology optimization(TO),a numerical technique to find the optimalmaterial layoutwith a given design domain,has attracted interest from researchers in the field of structural optimization in recent years.For beginner... Topology optimization(TO),a numerical technique to find the optimalmaterial layoutwith a given design domain,has attracted interest from researchers in the field of structural optimization in recent years.For beginners,opensource codes are undoubtedly the best alternative to learning TO,which can elaborate the implementation of a method in detail and easily engage more people to employ and extend the method.In this paper,we present a summary of various open-source codes and related literature on TO methods,including solid isotropic material with penalization(SIMP),evolutionary method,level set method(LSM),moving morphable components/voids(MMC/MMV)methods,multiscale topology optimization method,etc.Simultaneously,we classify the codes into five levels,fromeasy to difficult,depending on their difficulty,so that beginners can get started and understand the form of code implementation more quickly. 展开更多
关键词 Topology optimization open-source code optimization methods code classification BEGINNERS
在线阅读 下载PDF
HSPM:A Better Model to Effectively Preventing Open-Source Projects from Dying 被引量:1
12
作者 Zhifang Liao Fangying Fu +3 位作者 Yiqi Zhao Sui Tan Zhiwu Yu Yan Zhang 《Computer Systems Science & Engineering》 SCIE EI 2023年第10期431-452,共22页
With the rapid development of Open-Source(OS),more and more software projects are maintained and developed in the form of OS.These Open-Source projects depend on and influence each other,gradually forming a huge OS pr... With the rapid development of Open-Source(OS),more and more software projects are maintained and developed in the form of OS.These Open-Source projects depend on and influence each other,gradually forming a huge OS project network,namely an Open-Source Software ECOsystem(OSSECO).Unfortunately,not all OS projects in the open-source ecosystem can be healthy and stable in the long term,and more projects will go from active to inactive and gradually die.In a tightly connected ecosystem,the death of one project can potentially cause the collapse of the entire ecosystem network.How can we effectively prevent such situations from happening?In this paper,we first identify the basic project characteristics that affect the survival of OS projects at both project and ecosystem levels through the proportional hazards model.Then,we utilize graph convolutional networks based on the ecosystem network to extract the ecosystem environment characteristics of OS projects.Finally,we fuse basic project characteristics and environmental project characteristics and construct a Hybrid Structured Prediction Model(HSPM)to predict the OS project survival state.The experimental results show that HSPM significantly improved compared to the traditional prediction model.Our work can substantially assist OS project managers in maintaining their projects’health.It can also provide an essential reference for developers when choosing the right open-source project for their production activities. 展开更多
关键词 Project survival prediction open-source ecosystem open-source project open-source health graph neural networks
在线阅读 下载PDF
Open-Source Hardware Is a Low-Cost Alternative for Scientific Instrumentation and Research 被引量:7
13
作者 Daniel K. Fisher Peter J. Gould 《Modern Instrumentation》 2012年第2期8-20,共13页
Scientific research requires the collection of data in order to study, monitor, analyze, describe, or understand a particular process or event. Data collection efforts are often a compromise: manual measurements can b... Scientific research requires the collection of data in order to study, monitor, analyze, describe, or understand a particular process or event. Data collection efforts are often a compromise: manual measurements can be time-consuming and labor-intensive, resulting in data being collected at a low frequency, while automating the data-collection process can reduce labor requirements and increase the frequency of measurements, but at the cost of added expense of electronic data-collecting instrumentation. Rapid advances in electronic technologies have resulted in a variety of new and inexpensive sensing, monitoring, and control capabilities which offer opportunities for implementation in agricultural and natural-resource research applications. An Open Source Hardware project called Arduino consists of a programmable microcontroller development platform, expansion capability through add-on boards, and a programming development environment for creating custom microcontroller software. All circuit-board and electronic component specifications, as well as the programming software, are open-source and freely available for anyone to use or modify. Inexpensive sensors and the Arduino development platform were used to develop several inexpensive, automated sensing and datalogging systems for use in agricultural and natural-resources related research projects. Systems were developed and implemented to monitor soil-moisture status of field crops for irrigation scheduling and crop-water use studies, to measure daily evaporation-pan water levels for quantifying evaporative demand, and to monitor environmental parameters under forested conditions. These studies demonstrate the usefulness of automated measurements, and offer guidance for other researchers in developing inexpensive sensing and monitoring systems to further their research. 展开更多
关键词 open-source HARDWARE ARDUINO Microcontrollers Sensors Datalogger
暂未订购
From hardware store to hospital:a COVID-19-inspired,cost-effective,open-source,in vivo-validated ventilator for use in resource-scarce regions 被引量:1
14
作者 Matthew H.Park Yuanjia Zhu +9 位作者 Hanjay Wang Nicholas ATran Jinsuh Jung Michael JPaulsen Annabel M.Imbrie‑Moore Samuel Baker Robert Wilkerson Mateo Marin‑Cuartas Danielle M.Mullis Y.Joseph Woo 《Bio-Design and Manufacturing》 SCIE EI CAS CSCD 2022年第1期133-140,共8页
Resource-scarce regions with serious COVID-19 outbreaks do not have enough ventilators to support critically ill patients,and these shortages are especially devastating in developing countries.To help alleviate this s... Resource-scarce regions with serious COVID-19 outbreaks do not have enough ventilators to support critically ill patients,and these shortages are especially devastating in developing countries.To help alleviate this strain,we have designed and tested the accessible low-barrier in vivo-validated economical ventilator(ALIVE Vent),a COVID-19-inspired,cost-effective,open-source,in vivo-validated solution made from commercially available components.The ALIVE Vent operates using compressed oxygen and air to drive inspiration,while two solenoid valves ensure one-way flow and precise cycle timing.The device was functionally tested and profiled using a variable resistance and compliance artificial lung and validated in anesthetized large animals.Our functional test results revealed its effective operation under a wide variety of ventilation conditions defined by the American Association of Respiratory Care guidelines for ventilator stockpiling.The large animal test showed that our ventilator performed similarly if not better than a standard ventilator in maintaining optimal ventilation status.The FiO2,respiratory rate,inspiratory to expiratory time ratio,positive-end expiratory pressure,and peak inspiratory pressure were successfully maintained within normal,clinically validated ranges,and the animals were recovered without any complications.In regions with limited access to ventilators,the ALIVE Vent can help alleviate shortages,and we have ensured that all used materials are publicly available.While this pandemic has elucidated enormous global inequalities in healthcare,innovative,cost-effective solutions aimed at reducing socio-economic barriers,such as the ALIVE Vent,can help enable access to prompt healthcare and life saving technology on a global scale and beyond COVID-19. 展开更多
关键词 COVID-19 VENTILATOR open-source
暂未订购
Analysis and Simulations of Open-Source Intelligence Process System Dynamics from User’s Perspective 被引量:1
15
作者 Huan Liu Zhenyu Tang +1 位作者 Ning Zhao Wei Qian 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第1期541-558,共18页
In today’s society with advanced Internet,the amount of information increases dramatically with each passing day,which leads to increasingly complex processes of open-source intelligence.Therefore,it is more importan... In today’s society with advanced Internet,the amount of information increases dramatically with each passing day,which leads to increasingly complex processes of open-source intelligence.Therefore,it is more important to rationalize the operation mode and improve the operation efficiency of open-source intelligence under the premise of satisfying users’needs.This paper focuses on the simulation study of the process system of opensource intelligence from the user’s perspective.First,the basic concept and development status of open-source intelligence are introduced in details.Second,six existing intelligence operation process models are summarized and their advantages and disadvantages are compared in focus.Based on users’preference,the open-source intelligence system simulation theory model is constructed from four aspects:intelligence collection,intelligence processing,intelligence analysis,and intelligence delivery.Meanwhile,the dynamics model of the open-source intelligence process system is constructed based on the open-source intelligence system simulation theoretical model,which specifically includes five parts:determination of system boundary,construction of causal loop diagram,construction of stock flow diagram,writing ofmathematical equations,and system sensitivity test.Finally,the system simulation results were analyzed.It was found that improving the system of intelligence agencies,opening up government affairs,improving the professional level of intelligence personnel,strengthening the communication and cooperation among personnel of various intelligence departments,and expressing intelligence products through diverse forms can effectively improve the operational efficiency of the open-source intelligence process system. 展开更多
关键词 open-source intelligence system dynamics FEEDBACK user demand deviation
在线阅读 下载PDF
Sex differences and effects of oestrogen in rat gastric mucosal defence 被引量:1
16
作者 Richard Shore Hakan Bjorne +4 位作者 Yoko Omoto Anna Siemiatkowska Jan-Ake Gustafsson Mats Lindblad Lena Holm 《World Journal of Gastroenterology》 SCIE CAS 2017年第3期426-436,共11页
AIM To evaluate sex differences and the effects of oestrogen administration in rat gastric mucosal defence.METHODS Sex differences in gastric mucus thickness and accumulation rate, absolute gastric mucosal blood flow ... AIM To evaluate sex differences and the effects of oestrogen administration in rat gastric mucosal defence.METHODS Sex differences in gastric mucus thickness and accumulation rate, absolute gastric mucosal blood flow using microspheres, the integrity of the gastric mucosal epithelium in response to a chemical irritant and the effects of oestrogen administration on relative gastric mucosal blood flow in an acute setting was assessed in an in vivo rat experimental model. Subsequently, sex differences in the distribution of oestrogen receptors and calcitonin gene related peptide in the gastric mucosa of animals exposed to oestrogen in the above experiments was evaluated using immunohistochemistry.RESULTS The absolute blood flow in the GI-tract was generally higher in males, but only significantly different in the corpus part of the stomach (1.12 ± 0.12 m L/min·g in males and 0.51 ± 0.03 m L/min·g in females) (P = 0.002). After removal of the loosely adherent mucus layer the thickness of the firmly adherent mucus layer in males and females was 79 ± 1 μm and 80 ± 3 μm respectively. After 60 min the mucus thickness increased to 113 ± 3 μm in males and 121 ± 3 μm in females with no statistically significant difference seen between the sexes. Following oestrogen administration(0.1 followed by 1 μg/kg·min), mean blood flow in the gastric mucosa decreased by 31% [68 ± 13 perfusion units (PFU)] in males which was significantly different compared to baseline(P = 0.02). In females however, mean blood flow remained largely unchanged with a 4% (5 ± 33 PFU) reduction. The permeability of the gastric mucosa increased to a higher level in females than in males (P = 0.01) after taurocholate challenge. However, the calculated mean clearance increase did not significantly differ between the sexes [0.1 ± 0.04 to 1.1 ± 0.1 m L/min·100 g in males and 0.4 ± 0.3 to 2.1 ± 0.3 m L/min·100 g in females(P = 0.065)]. There were no significant differences between 17β-Estradiol treated males (mean ratio of positive staining ± SEM)(0.06 ± 0.07) and females(0.11 ± 0.11) in the staining of ERα (P = 0.24). Also, there were no significant differences between 17β-Estradiol treated males (0.18 ± 0.21) and females (0.06 ± 0.12) in the staining of ERβ (P = 0.11). Finally, there were no significant differences between 17β-Estradiol treated males (0.04 ± 0.05) and females (0.11 ± 0.10) in the staining of CGRP(P = 0.14).CONCLUSION Gastric mucosal blood flow is higher in male than in female rats and is reduced in male rats by oestrogen administration. 展开更多
关键词 Sex differences Gastric mucosal defence Blood flow OESTROGEN Gastric physiology MUCUS
暂未订购
First Announcement and Call for Papers SECOND INTERNATIONAL SYMPOSIUM ON FLOOD DEFENCE (ISFD '2002) 被引量:1
17
《Journal of Geographical Sciences》 SCIE CSCD 2001年第2期245-249,共5页
关键词 First Announcement and Call for Papers SECOND INTERNATIONAL SYMPOSIUM ON FLOOD defence ISFD FLOOD
在线阅读 下载PDF
Temporal Dynamics of Antioxidant Defence System in Relation to Polyamine Catabolism in Rice under Direct-Seeded and Transplanted Conditions
18
作者 Manisha KUMARI Bavita ASTHIR Navtej Singh BAINS 《Rice science》 SCIE 2014年第6期343-353,共11页
Six rice cultivars viz. PR120, PR116, Feng Ai Zan, PR115, PAU201 and Punjab Mehak 1 under the direct-seeded and transplanted conditions were used to investigate the involvement of antioxidative defence system in relat... Six rice cultivars viz. PR120, PR116, Feng Ai Zan, PR115, PAU201 and Punjab Mehak 1 under the direct-seeded and transplanted conditions were used to investigate the involvement of antioxidative defence system in relation to polyamine catabolism in temporal regulation of developing grains. Activities of ascorbate peroxidase (APx), guaiacol peroxidase (GPx), catalase (CAT), superoxide dismutase (SOD), polyamine oxidases (PAO) and contents of ascorbate, a-tocopherol, proline and polyamines increased gradually until mid-milky stage and then declined towards maturity stage under both planting conditions. The transplanted condition led to higher activities of antioxidative enzymes (APx, GPx and CAT) and contents of ascorbate, a-tocopherol and proline whereas the direct-seeded condition had elevated levels of PAO and SOD activities and contents of polyamines, lipid peroxide and hydrogen peroxide. Cultivars Feng Ai Zan and PR120 exhibited superior tolerance over other cultivars by accumulating higher contents of ascorbate, a-tocopherol and proline with increasing level of PAO and SOD activities under the direct-seeded condition. However, under the transplanted condition PR116 and PAU201 showed higher activities of antioxidative enzymes with decreasing content of lipid peroxide. Therefore, we concluded that under the direct-seeded condition, enhancements of polyamines content and PAO activity enabled rice cultivars more tolerant to oxidative stress, while under the transplanted condition, antioxidative defence with decreasing of lipid peroxide content was closely associated with the protection of grains by maintaining membrane integrity during rice grain filling. The results indicated that temporal dynamics of H2O2 metabolic machinery was strongly up-regulated especially at the mid-milky stage. 展开更多
关键词 antioxidant defence system direct-seeded membrane stability polyamines RICE transplanted condition
在线阅读 下载PDF
Implication of Oxidative Stress and Antioxidant Defence Systems in Symptomatic and Asymptomatic Plasmodium falciparum Malaria Infection among Children Aged 1 to 15 Years in the Mount Cameroon Area
19
作者 Tambong Ako Ojongnkpot David Denis Sofeu-Feugaing +2 位作者 Vanessa Tita Jugha Germain Sotoing Taiwe Helen Kuokuo Kimbi 《Journal of Biosciences and Medicines》 CAS 2023年第2期124-145,共22页
It is known that the pathogenicity of Plasmodium induces the breakdown of haemoglobin, which leads to the induction of oxidative stress. This study aimed to identify the possible effects of oxidative stress and antiox... It is known that the pathogenicity of Plasmodium induces the breakdown of haemoglobin, which leads to the induction of oxidative stress. This study aimed to identify the possible effects of oxidative stress and antioxidant defence systems in symptomatic and asymptomatic Plasmodium falciparum malaria infection in children (1 - 15 years old) in the Mount Cameroon vicinity. This cross-sectional study involved blood samples collected from 473 children and examined for malaria parasitaemia. Full blood counts were performed using an automated haemoanalyser. Serum oxidative stress status (malondialdehyde (MDA), nitric oxide (NO), reduced glutathione (GSH), catalase (CAT), superoxide dismutase (SOD) and vitamin C (Vit C)) were each determined by colorimetric enzymatic assays. The prevalence of malaria parasite infection was 32.1% among the participants. Out of that, 62.5% of patients with parasitaemia were symptomatic. Anaemia prevalence increased significantly with parasite density. MDA levels were significantly higher in patients with malaria symptoms than in those without symptoms. A significant and positive correlation was detected between MDA (r = 0.831, P < 0.05), NO (r = 0.779, P < 0.05), and malaria parasite density while, a significant and negative relationship occurred between parasite density and GSH (r = ?0.763, P < 0.05) and Vit C (r = ?0.826, P < 0.05) levels, SOD (r = ?0.621, P < 0.05) and CAT (r = ?0.817, P < 0.05) activities. The SOD activity and GSH level significantly decreased (P < 0.05) with an increase in the MDA levels. These findings showed that MDA and nitric oxide levels increased both in malaria participants with or without symptoms. A similar decrease in the antioxidant defence system was observed in both symptomatic and asymptomatic patients. Therefore, there is a need to develop public health policies that encourage routine diagnosis and treatment of malaria in seemingly healthy people (asymptomatic cases), and this will play an essential role in controlling malaria in tropical countries. 展开更多
关键词 MALARIA ASYMPTOMATIC SYMPTOMATIC Oxidative Stress Antioxidant defence System
暂未订购
An open-source albedo-wand for the measurement of sea ice albedo
20
作者 Christian KATLEIN 《Advances in Polar Science》 CSCD 2019年第2期106-117,共12页
Surface albedo is defined as the ratio of incident and reflected solar irradiance and describes the ability of a surface to reflect, rather than absorb incident solar shortwave radiation. It is thus a crucial paramete... Surface albedo is defined as the ratio of incident and reflected solar irradiance and describes the ability of a surface to reflect, rather than absorb incident solar shortwave radiation. It is thus a crucial parameter in the climate system, particularly in the polar oceans. Sea ice albedo is a main driver for light transmission into the polar oceans and thus has a high impact on ocean warming, ice melting and marine primary production. During spring and summer, sea ice albedo can exhibit a significant spatial variability caused by meltwater accumulations on the ice. While complex and expensive solutions for albedo measurements are already available, we want to present a simple open-source design that allows for affordable mapping of spatially varying surface albedo on sea ice and beyond. Our solution is based on off-the-shelf components, such as an Arduino microcontroller integrating affordable light sensors, a GPS unit, data recording on memory card and data display into a simple field strengthened unit. We provide example data from two Arctic field deployments showing the capabilities and limitations of this system. 展开更多
关键词 sea ICE ALBEDO spatial VARIABILITY mapping GPS open-source
在线阅读 下载PDF
上一页 1 2 125 下一页 到第
使用帮助 返回顶部