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Two-dimensional investigation of characteristic parameters and their gradients for the self-generated electric and magnetic fields of laser-induced zirconium plasma

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Plasma Science and Technology 2024年第5期26卷 138-155页

作者： Tayyaba sajid Shazia bashir Mahreen AKRAM Maira RAZZAQ Khaliq MAHMOOD Centre for Advanced Studies in Physics Institute of PhysicsGovernment College University LahoreLahore 54000Pakistan Department of Physics Institute of PhysicsGovernment College University LahoreLahore 54000Pakistan

Two-dimensional diagnosis of laser-induced zirconium(Zr)plasma has been experimentally performed using the time-of-flight method by employing Faraday cups in addition to electric and magnetic *** characteristic parameters of laser-induced Zr plasma have been evaluated as a function of different laser irradiances ranging from 4.5 to 11.7 GW cm-2 at different axial positions of 1–4 cm with a fixed radial distance of 2 cm.A well-supporting correlation between the plume parameters and the laser-plasma-produced spontaneous electric and magnetic(E and B)fields was *** measurements of the characteristic parameters and spontaneously induced fields were observed to have an increasing trend with the increasing laser ***,when increasing the spatial distance in both the axial and radial directions,the plasma parameters(electron/ion number density,temperature and kinetic energy)did not show either continuously increasing or decreasing trends due to various kinetic and dynamic processes during the spatial evolution of the ***,the E and B fields were observed to be always diffusing away from the *** radial component of electron number densities remained higher than the axial number density component,whereas the axial ion number density at all laser irradiances and axial distances remained higher than the radial ion number *** higher axial self-generated electric field(SGEF)values than radial SGEF values are correlated with the effective charge-separation mechanism of electrons and *** generation of a self-generated magnetic field is observed dominantly in the radial direction at increasing laser irradiance as compared to the axial one due to the deflection of fast-moving electrons and the persistence of two-electron temperature on the radial axis.

关键词： Faraday cup axial and radial expansion space-charge effect laser-induced zirconium plasma two-electron temperature distribution self-generated electric and magnetic fields

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Role of Polyamines in Ozone Exposed Ischemic-Reperfused Hearts

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American Journal of Analytical Chemistry 2011年第7期2卷 832-839页

作者： Rajat Sethi Sai Raghuveer Chava sajid bashir Mauro E. Castro 不详

The effect of chronic ozone exposure to ischemia reperfusion (I/R) injury in isolated perfused rat hearts was previously demonstrated. The present study tested our hypothesis that chronic ozone exposure led to attenuation of polyamines in the heart, which may limit sensitivity to I/R. Sprague Dawley rats were continuously exposed for 8 hrs/day for 28 days to filtered air or 0.8 ppm ozone. Isolated hearts were previously subjected to 0.5 hour of global ischemia followed by 1 hour of reperfusion after which global polyamine content was examined between the two groups. Spermidine production was significantly increased in the experimental group compared to control group (of I/R hearts). These results suggest that ozone-induced sensitivity to chronic I/R injury activates myocardial polyamine stress response characterized by increased enzymatic activities and accumulation of spermidine. Collectively, these results suggest that I/R possibly disturbs polyamine metabolism, and increased oxidative stress and concomitant reduced myocardial cell viability.

关键词： Environmental Pollutants Cardiovascular Disease Polyamines Ischemia-Reperfusion (I/R) Injury Oxidative Stress

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An Improved High Performance Liquid Chromatographic Method for Identification and Quantization of Polyamines as Benzoylated Derivatives

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American Journal of Analytical Chemistry 2011年第4期2卷 456-469页

作者： Rajat Sethi Sai Raghuveer Chava sajid bashir Mauro E. Castro 不详

A simple reversed phase HPLC method was developed for the determination of Putrescine, Cadaverine and Spermidine (a class of polyamines) in their benzoylated form from external known standards. In the optimization procedure, a number of parameters were examined: 1) Solvent used in the extraction of standard polyamines (diethyl ether versus chloroform);2) Solvent used in the elution of the polyamine (methanol versus acetonitrile);3) Mode of derivatization and extraction step(s) (derivatization and extraction performed together versus derivatization and extraction performed separately);and 4) Other instrumental parameters (such as UV detection wavelength, gradient profiles). The advantages of our method, relative to the standard Morgan method are: a) decreased chromatographic runtime, b) ease of preparation with good resolution, sensitivity, and reproducibility using a standard RP-HPLC method.

关键词： Polyamine RP-HPLC Standardization Benzoylation

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纳米金属和复合物在肿瘤诊断和治疗中的应用（英文）

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黑龙江大学自然科学学报 2014年第1期31卷 65-79页

作者： bashir sajid 王婷婷 PALAKURTHI Srinath 刘静波美国德克萨斯州农工大学金斯维尔分校化学系金斯维尔78363 美国德克萨斯州农工大学健康科学中心药学系金斯维尔78363 美国劳伦斯伯克利国家实验室先进光源伯克利94720

本文讨论利用三类纳米材料对癌症进行诊断和治疗(简称诊治学)。这三类材料包含纳米金属、过渡金属氧化物和金属有机配合物,它们可通过化学湿法来制备。纳米技术具有精确构建细小材料的优越性,所以纳米材料被用来从细胞和基因水平上靶向... 详细信息

本文讨论利用三类纳米材料对癌症进行诊断和治疗(简称诊治学)。这三类材料包含纳米金属、过渡金属氧化物和金属有机配合物,它们可通过化学湿法来制备。纳米技术具有精确构建细小材料的优越性,所以纳米材料被用来从细胞和基因水平上靶向攻击癌细胞,其精确度高、副作用小。目前的挑战在于对转移性癌症、抗药性癌症和肿瘤干细胞的治疗,通过有效设计作为载体的纳米材料,可以实现药物定向传递,进而实现对成体干细胞、胸腺T细胞的免疫治疗。作者讨论了上述纳米材料以及它们在癌症诊治中的应用,重点讨论了纳米材料的湿化学合成、性能及应用,该类材料具有独特的拓扑结构和孔隙度,因而具有高效靶向药物输送功能。另外,该类材料(特别是金属有机配合物)具有可调的颗粒大小、形状及组成,在靶向癌症治疗中,显示出循环半衰期长的优点。该文也就材料对肿瘤的诊治效率及纳米材料运作机制进行了探讨,以期克服目前所使用纳米材料的局限性。

关键词：关键词纳米材料癌症诊治材料合成表征毒性

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A Review of Image Steganography Based on Multiple Hashing Algorithm

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Computers, Materials & Continua 2024年第8期80卷 2463-2494页

作者： Abdullah Alenizi Mohammad sajid Mohammadi Ahmad A.Al-Hajji Arshiya sajid Ansari Department of Information Technology College of Computer and Information SciencesMajmaah UniversityAl-Majmaah11952Saudi Arabia Department of Computer Science College of Engineering and Information TechnologyOnaizah CollegesQassim56312Saudi Arabia

Steganography is a technique for hiding secret messages while sending and receiving communications through a cover *** ancient times to the present,the security of secret or vital information has always been a significant *** development of secure communication methods that keep recipient-only data transmissions secret has always been an area of ***,several approaches,including steganography,have been developed by researchers over time to enable safe data *** this review,we have discussed image steganography based on Discrete Cosine Transform(DCT)algorithm,*** have also discussed image steganography based on multiple hashing algorithms like the Rivest–Shamir–Adleman(RSA)method,the Blowfish technique,and the hash-least significant bit(LSB)*** this review,a novel method of hiding information in images has been developed with minimal variance in image bits,making our method secure and effective.A cryptography mechanism was also used in this *** encoding the data and embedding it into a carry image,this review verifies that it has been ***,embedded text in photos conveys crucial signals about the *** review employs hash table encryption on the message before hiding it within the picture to provide a more secure method of data *** the message is ever intercepted by a third party,there are several ways to stop this operation.A second level of security process implementation involves encrypting and decrypting steganography images using different hashing algorithms.

关键词： Image steganography multiple hashing algorithms Hash-LSB approach RSA algorithm discrete cosine transform(DCT)algorithm blowfish algorithm

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Contextual Challenges in the Implementation of the Alliance for Maternal and Newborn Health Improvement, Prospective Cohort Study, an Experience from Rural Pakistan

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Open Journal of Preventive Medicine 2021年第7期11卷 334-346页

作者： Yaqub Wasan Shabina Ariff Amjad Hussain Sheraz Ahmed Mansoor Ali Abro Imran Ahmed Atif Habib sajid bashir Soofi Center of Excellence in Women & Child Health Aga Khan University Karachi Pakistan Department of Paediatrics and Child Health Aga Khan University Karachi Pakistan

Introduction: Improving maternal and newborn survival needs robust data on patterns of morbidity and mortality from well-characterized cohorts. It is equally important for researchers to document and understand the contextual challenges of data collection and how they are addressed. Methods: This was a prospective cohort study implemented from December 2012 to August 2014 in Matiari, Pakistan. A total of 11,315 pregnancies were enrolled. Participants were approached at home for sequential data collection through the standard pretested structured questionnaires. Some indicators were sourced through health facility records. Information on field challenges gathered through field diaries and minutes of meetings with field staff. Results: Inaccurate reporting of last menstrual period (LMP) dates caused difficulties in the planning and completion of antenatal data collection visits at scheduled gestational weeks. We documented ultrasound reports wherever available, relied on quickening technique, and implemented a seasonal event calendar to help mothers’ recall their LMP. Health system coordinators of public sector and private healthcare providers were individually approached for maximum data collection. But an unregulated private health system with poor record maintenance and health care providers’ reluctance for cooperation posed a greater challenge in data collection. Conclusions: Within a broader understanding of the health systems and socio-cultural environment, temporal and spatial feasibility of data collection should be considered thoroughly at the early stages of study designing, planning, resource allocation, and implementation. Pre-defined regular and need-based meetings with each tier of data collection teams and study managers help to reinvigorate field execution plans and optimize both quantity and quality of study data.

关键词： Maternal and Newborn Health Research Contextual Challenges Data Collection Field Implementation Lessons Learnt

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Recent progress and prospects of electrolytes for electrocatalytic nitrogen reduction toward ammonia

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Chinese Chemical Letters 2024年第4期35卷 3-16页

作者： sajid Mahmood Haiyan Wang Fang Chen Yijun Zhong Yong Hu Key Laboratory of the Ministry of Education for Advanced Catalysis Materials Department of ChemistryZhejiang Normal UniversityJinhua 321004China The Center for Applied Mathematics and Bioinformatics(CAMB) Gulf University for Science and TechnologyMishref 32093Kuwait Hangzhou Institute of Advanced Studies Zhejiang Normal UniversityHangzhou 311231China

Electrochemical nitrogen reduction reaction(ENRR) provides a promising strategy to achieve sustainable synthesis of ammonia. However, despite great efforts devoted to this research field, the problems such as low energy efficiency and weak selectivity still impede its practical implementation. Most of the research to date has been concentrated on creating sophisticated electrocatalysts, and adequate knowledge of electrolytes is still lacking. Herein, the recent progress in electrolytes for ENRR, including alkaline, neutral,acidic, water-in-salt, organic, ionic liquid, and mixed water-organic electrolytes, is thoroughly reviewed to obtain an in-depth understanding of their effects on electrocatalytic performance. Recently developed representative electrocatalysts in various types of electrolytes are also introduced, and future research priorities of different electrolytes are proposed to develop new and efficient ENRR systems.

关键词： Electrocatalytic nitrogen reduction Ammonia Electrolytes Production rate Faradaic efficiency

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Determinants of Health Care Seeking Behaviors in Puerperal Sepsis in Rural Sindh, Pakistan: A Qualitative Study

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Open Journal of Preventive Medicine 2020年第9期10卷 255-266页

作者： Shabina Ariff Fatima Mir Farhana Tabassum Farrukh Raza Atif Habib Ali Turab Amnesty LeFevre Linda A. Bartlett sajid bashir Soofi Zulfiqar A. Bhutta Department of Paediatric and Child Health Aga Khan University Karachi Pakistan Center of Excellence in Women & Child Health Aga Khan University Karachi Pakistan Department of International Health Johns Hopkins Bloomberg School of Public Health Baltimore MD USA

Background: Puerperal sepsis (PS) is one of the major causes of maternal death, contributing to 26,000 deaths per year in developing countries. Early recognition and treatment are essential to managing PS, but numerous social, cultural and technical barriers prevent or delay access to care and necessary medical attention. Through this qualitative study, we identified barriers to care seeking for puerperal sepsis among recently delivered women in Matiari, Pakistan. Methods: We conducted 20 in-depth interviews among recently delivered women with and without sepsis and their family members in September 2012. Key informant interviews were conducted with 14 healthcare providers and traditional birth attendants. The themes used for content analysis were knowledge of danger signs, factors affecting care seeking and local treatment practices for postpartum sepsis. Results: A total of 34 interviews were conducted. Recently delivered women, their family members and traditional birth attendants were unaware of the word PS or the local translated term for PS. However, they were familiar with most of the individual symptoms associated with PS. Healthcare providers were aware of the condition and the associated symptoms. The healthcare providers’ understanding of the seriousness of PS was directly proportional their age and clinical experience. The most common barriers to care seeking was the division of labor within the household, obtaining permission from the primary decision maker, access to transportation, lack of financial resources and support from family members. Conclusion: To improve maternal care seeking behaviors for PS, interventions focusing on increasing knowledge of PS, addressing gender inequality, implementing an affordable community transport service and enhancing TBA’s knowledge and skills to manage PS need to be implemented.

关键词： Puerperal Sepsis Qualitative Care Seeking Barrier Maternal Health

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羟基苯甲酸异构体在溶液和固相中的吸收系数

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黑龙江大学自然科学学报 2019年第6期36卷 688-694,F0003页

作者： bashir sajid CHAVA Sai Raghuveer 刘静波 DERRICK JPeter 英国华威大学质谱研究所考文垂CV47AL 美国德克萨斯农机大学金斯维尔分校化学系金斯维尔78363 美国Emergent BioSolutions公司圣地亚哥20877 新西兰奥克兰大学物理系奥克兰1061

基质辅助激光解吸/电离质谱(MALDI)中所用的溶剂对晶体的形成和质谱的质量起着重要的作用。研究了以二羟基苯甲酸(DHB)的x,j-异构体为基质的固相和液相紫外吸收材料。采用三种不同的溶剂体系制备固态DHB晶体,其中乙腈/水二元体系(L1)或... 详细信息

基质辅助激光解吸/电离质谱(MALDI)中所用的溶剂对晶体的形成和质谱的质量起着重要的作用。研究了以二羟基苯甲酸(DHB)的x,j-异构体为基质的固相和液相紫外吸收材料。采用三种不同的溶剂体系制备固态DHB晶体,其中乙腈/水二元体系(L1)或乙醇/水二元体系(L2)是制备具有均匀尺寸晶体的最佳溶剂。该结果对UV-MALDI基质在成像、蛋白质组学和复杂混合物分析等领域的应用具有指导意义。

关键词： MALDI DHB 吸收系数质普

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从碳到氢能源:昨天、今天、明天

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自然杂志 2018年第6期40卷 420-426页

作者： bashir sajid 甄强李榕李翠霞刘静波美国德克萨斯农工大学-金斯威尔校区上海大学纳米科学与技术研究中心/先进功能材料实验室上海200444 兰州理工大学材料科学与工程学院兰州730050 美国德克萨斯农工大学大学城德克萨斯州77845

简述了近期能源的发展动向,特别以氢能源为重点,就产氢、储氢及利用氢三个方面进行阐述。氢气作为高能量密度的燃料载体在提供能量的过程中可实现或接近实现无碳排放。作者及团队发现,将分散式电解水产氢技术应用在燃料电池模型汽车上,... 详细信息

简述了近期能源的发展动向,特别以氢能源为重点,就产氢、储氢及利用氢三个方面进行阐述。氢气作为高能量密度的燃料载体在提供能量的过程中可实现或接近实现无碳排放。作者及团队发现,将分散式电解水产氢技术应用在燃料电池模型汽车上,模型车的运行速度及里程可提高30%以上。

关键词：氢能源产氢储氢利用氢

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