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Petrophysical relationship for density prediction using Vp & Vs in Meyal oilfield, Potwar sub-basin, Pakistan

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Geodesy and Geodynamics 2018年第2期9卷 151-155页

作者： Gulraiz akhter Younis Khan Anees Ahmad Bangash Faisal Shahzad Yawar Hussain Department of Earth Sciences Quaid-i-Azam University Key Laboratory of Mineral Resources Institute of Geology and Geophysics Chinese Academy of Sciences National Centre of Excellence in Geology (NCEGS) University of Peshawar Research and Development Department Department of Civil and Environmental Engineering University of Brasilia

Conventional petrophysical investigations are based on P-wave seismic velocity analysis to predict density information, while ignoring the important S-wave velocity. This study is based on S-wave velocity analysis of density estimation of Meyal Oil Field(Potwar Plateau, Pakistan), which reveals a very high correlation(R=0.87) between predicted and actual density. Since the availability of S-wave velocity(Vs) data increases, it’s highly appreciable to take into account the contribution of Vs in improvement of density estimates. This investigation only focuses on driving new constants(a = 1.92 and b = 0.186) for Gardner’s relationship to estimate density of pure carbonates(Vsh< 10%) in the study area, where the traditional model gave poorer density predictions. The proposed empirical expression with locally extracted unknowns from well log data proved its ability in terms of density prediction(showing very close agreement with measured densities) and best fitting the datasets at low as well as high density values when compared with Gardner’s equation. Based on our analysis, the exploratory study neither intends to replace the well established density estimation models nor to extend information over what information can possibly be extractable from Vp. However, our research does stimulate the growing use of Vs and importance of local unknown constants especially in carbonates reservoir interval to avoid misuse of most widely used Gardner relation in all geological settings.

关键词： Shale Gardner Potwar Carbonates S-Waves

The effect of tailing lipidation on the bioactivity of antimicrobial peptides and their aggregation tendency Special Issue:Emerging Investigators

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聚集体(英文)

聚集体(英文) 2023年第4期4卷 195-209页

作者： Bruce Lin Andrew Hung William Singleton Kevion K.Darmawan Rachael Moses Bicheng Yao Hongkang Wu Anders Barlow Marc-Antoine Sani Alastair J.Sloan Mohammed akhter Hossain John D.Wade Yuning Hong Neil M.O’Brien-Simpson Wenyi Li The Bio21 Institute of Molecular Science and Biotechnology University of MelbourneMelbourneVictoriaAustralia ACTV Research group Melbourne Dental SchoolCentre for Oral Health ResearchUniversity of MelbourneMelbourneVictoriaAustralia School of Science RMIT UniversityMelbourneVictoriaAustralia Melbourne Dental School Division of Basic and Clinical Oral SciencesUniversity of MelbourneMelbourneVictoriaAustralia Department of Biochemistry and Chemistry La Trobe Institute for Molecular ScienceLa Trobe UniversityMelbourneVictoriaAustralia Florey Institute of Neuroscience and Mental Health University of MelbourneMelbourneVictoriaAustralia School of Chemistry University of MelbourneMelbourneVictoriaAustralia Materials Characterisation and Fabrication Platform University of MelbourneMelbourneVictoriaAustralia

Antimicrobial peptides(AMPs)are potentially powerful alternatives to conven-tional antibiotics in combating multidrug resistance,given their broad spectrum of *** mainly interact with cell membranes through surface electrostatic potentials and the formation of secondary structures,resulting in permeability and destruction of target microorganism *** earlier work showed that two leading AMPs,MSI-78(4–20)and pardaxin(1–22),had potent antimicrobial activ-ity against a range of *** is known that the attachment of moderate-length lipid carbon chains to cationic peptides can further improve the functionality of these peptides through enhanced interactions with the membrane lipid bilayer,inducing membrane curvature,destabilization,and potential ***,in this work,we aimed to investigate the antimicrobial activity,oligomerization propensity,and lipid-membrane binding interactions of a range of N-terminal lipidated analogs of MSI-78(4–20)and pardaxin(1–22).Molecular modeling results suggest that aggregation of the N-lipidated AMPs may impart greater structural stability to the peptides in solu-tion and a greater depth of lipid bilayer insertion for the N-lipidated AMPs over the parental *** experimental and computationalfindings provide insights into how N-terminal lipidation of AMPs may alter their conformations,with subsequent effects on their functional properties in regard to their self-aggregation behavior,membrane interactions,and antimicrobial activity.

关键词： aggregation antimicrobial peptide lipidation membrane active peptide

Preparation of Chitin-PLA laminated composite for implantable application

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Bioactive Materials 2017年第4期2卷 199-207页

作者： Romana Nasrin Shanta Biswas Taslim Ur Rashid Sanjida Afrin Rumana akhter Jahan Papia Haque Mohammed Mizanur Rahman Department of Applied Chemistry and Chemical Engineering Faculty of Engineering and TechnologyUniversity of DhakaDhaka 1000Bangladesh Centre for Advanced Research in Sciences University of DhakaDhaka 1000Bangladesh

The present study explores the possibilities of using locally available inexpensive waste prawn shell derived chitin reinforced and bioabsorbable polylactic acid(PLA)laminated composites to develop new materials with excellent mechanical and thermal properties for implantable application such as in bone or dental *** at different concentration(1e20%of PLA)reinforced PLA films(CTP)were fabricated by solvent casting process and laminated chitin-PLA composites(LCTP)were prepared by laminating PLA film(obtained by hot press method)with CTP also by hot press method at 160*** effect of variation of chitin concentration on the resulting laminated composite's behavior was *** detailed physico-mechanical,surface morphology and thermal were assessed with different characterization technique such as FT-IR,XRD,SEM and *** FTIR spectra showed the characteristic peaks for chitin and PLA in the *** images showed an excellent dispersion of chitin in the films and *** analysis(TGA)showed that the complete degradation of chitin,PLA film,5%chitin reinforced PLA film(CTP2)and LCTP are 98%,95%,87%and 98%respectively at temperature of 500*** tensile strength of the LCTP was found 25.09 MPa which is significantly higher than pure PLA film(18.55 MPa)and CTP2 film(8.83 MPa).After lamination of pure PLA and CTP2 film,the composite(LCTP)yielded 0.265e1.061%water absorption from 30 min to 24 h immerse in water that is much lower than PLA and *** increased mechanical properties of the laminated films with the increase of chitin content indicated good dispersion of chitin into PLA and strong interfacial actions between the polymer and *** improvement of mechanical properties and the results of antimicrobial and cytotoxicity of the composites also evaluated and revealed the composite would be a suitable candidate for implant application in biomedical sector.

关键词： Chitin PLA LCTP composite Biomedical application Bone implants

Estimation of Nucleation Thermodynamical Parameters of La₂Sr₂xCuO₄ (LSCO) and YBa₂Cu₂O_7–δ (YBCO) Crystallizing from High Temperature Solution

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Crystal Structure Theory and Applications 2016年第2期5卷 17-23页

作者： Shahida akhter Deba Prasad Paul Department of Physics University of Chittagong Chittagong Bangladesh

The growth kinetics of LSCO and YBCO single crystals from high temperature solution of LSCO-CuO solute-solvent and YBCO-CuO solute-solvent systems has been investigated. Based on regular solution model and classical nucleation theory, the thermodynamical data investigated for the systems are used to determine the nucleation parameters: interfacial free energy, metastable zone-width, volume free energy, critical energy barrier for nucleation and radius of critical nucleus for LSCO and YBCO which leads to the understanding of the nucleation phenomena of LSCO and YBCO.

关键词： LSCO YBCO Interfacial Energy Metastable Zone-Width

Thalidomide Is an Adjunct Therapy for the Refractory Systemic Juvenile Idiopathic Arthritis Patients in a Tertiary Hospital Study

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Open Journal of Rheumatology and Autoimmune Diseases 2023年第2期13卷 51-63页

作者： Md. Taiyabur Rahman Mujammel Haque Farhana Faria Mohammed Mahbubul Islam Manik Kumar Talukder Mohammad Imnul Islam Shahana akhter Rahman Department of Paediatrics Bangabandhu Sheikh Mujib Medical University Dhaka Bangladesh

Background: Systemic JIA (sJIA) is one of the subtypes of JIA, which is most difficult to treat among all JIA cases. About 50% of sJIA cases did not respond to traditional disease modifying anti-rheumatic drugs (DMARDs)—metho-trexate (MTX). Thalidomide is an immunomodulating and anti-inflammatory drug that induces sustained improvement of refractory sJIA cases. Objectives: To evaluate the efficacy of thalidomide in refractory sJIA patients. Methods: This was a prospective interventional study carried out in the Paediatric Rheumatology and Immunology follow-up clinic run by the Department of Pediatrics, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka from January 2019 to July 2020. Twenty-five sJIA patients who were refractory to conventional DMARDs were included in this study. These patients were prescribed thalidomide at a dose of 3 - 5 mg/kg/day for six months and efficacy was assessed by using juvenile arthritis disease activity score (JADAS 27) at 12th and 24th weeks of treatment. Result: Active joint counts and ESR improvement were observed in 90.69%, 97.67% and 69.84%, 100% of sJIA patients respectively at 12th and 24th weeks of treatment. Improvement of physicians and parent global assessment of VAS were 77.56%, 97.43% and 70.62% and 96.04% respectively at 12th and 24th weeks of treatment. Improvement of the total score of JADAS-27 was 77.51% at 12th week and 97.52% at 24th of week follow-up which was statistically significant. Somnolence, constipation and paresthesia were found as common adverse effect in this study. Conclusion: Efficacy of thalidomide was assessed by JADAS 27 criteria showed significant improvement in refractory sJIA patients in this study. It may be concluded that Thalidomide is safe and effective as an adjunct therapy of refractory sJIA patients.

关键词： Juvenile Idiopathic Arthritis Thalidomide Refractory sJIA

GPS Workstation—A Static Point Averaging and Tracks Mapping Application

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Positioning 2013年第1期4卷 57-64页

作者： Khalid Amin Khan Gulraiz akhter Department of Earth Sciences Quaid-i-Azam University Islamabad Pakistan K-tron Research Inc. Rawalpindi Pakistan

This paper describes GPS Workstation, a general purpose navigation software which requires a low-cost GPS connected to the computer. It provides an integrated display of positioning data along with satellite positions, their signal strengths and data quality parameters. The software can be used for static point averaging of GPS data to get more precise positioning and real-time mapping of roads and tracks. It supports output of data in keyhole markup language (KML) as well as other formats for visualization of acquired data on Google Earth and geographic information systems. It can also be used to determine geo-referencing errors in Google Earth imagery for an area and can compensate the error by applying a constant X, Y shift. The software is available for distribution under the free software license.

关键词： GPS Real-Time Mapping Google Earth Data Averaging

Crystallization and Hardness of Melt Spun Fe_(73)Si_(13)B_9Nb_4Cu_1 Alloy

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Journal of Materials Science & Technology 2009年第1期25卷 48-52页

作者： J.I. akhter M. Iqbal M. Siddique M. Ahmad M.A. Haq M.A. Shaikh Z.Q. Hu Physics Division Pakistan Institute of Nuclear Science and Technology P. O. Nilore Islamabad Pakistan Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China Department of Chemical and Materials Engineering Pakistan Institute of Engineering and Applied Sciences P.O. Nilore Islamabad Pakistan

An alloy having composition Fe73Si13B9Nb4Cu1 was synthesized by melt spinning to investigate the kinetics of crystallization. Techniques of differential scanning calorimetry （DSC）, X-ray diffraction （XRD） and Mossbauer spectroscopy were employed to characterize the phases produced due to annealing at various temperatures. High temperature DSC revealed two stage crystallization reactions. First stage, crystallization occurs at temperature around 514℃ with the production of α-Fe （bcc） and Fe3Si phases. In the second stage, Fe2B and α-Fe （Si,Nb） phases were produced. Mossbauer results revealed the formation of Fe3Si, Fe13Si3 and Fe7Si1 in the first stage and Fe3Si, Fe13Si3, Fe2B and α-Fe （Si,Nb） phases in the second stage of crystallization. An abrupt change in average internal magnetic field was observed at 500℃. The maximum hardness value was found for the sample heat-treated at 500℃.

关键词： Amorphous alloy Crystallization Mossbauer spectroscopy Hardness

Outcomes of colon self-expandable metal stents for malignant vs benign indications at a tertiary care center and review of literature

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World Journal of Gastrointestinal Endoscopy 2023年第4期15卷 309-318页

作者： Saqib Walayat Andrew J Johannes Mark Benson Eric Nelsen Ahmed akhter Gregory Kennedy Anurag Soni Mark Reichelderfer Patrick Pfau Deepak Gopal Department of Gastroenterology University of WisconsinMadisonWI 53705United States Department of Gastroenterology and Hepatology University of WisconsinMadisonWI 53705United States Gastroenterology Park Nicollet Digestive and Endoscopy CenterMethodist HospitalSt.Louis ParkMinneapolisMN 55426United States Department of Surgery University of Alabama-Birmingham School of MedicineBriminghamAL 35243United States Department of Medicine University of Wisconsin School of Medicine and Public HealthMadisonWI 53705United States Division of Gastroenterology and Hepatology Department of MedicineUniversity of Wisconsin Hospitals and ClinicsMadisonWI 53705United States

BACKGROUND Endoscopic placement of a self-expandable metal stent(SEMS)is a minimally invasive treatment for use in malignant and benign colonic ***,their widespread use is still limited with a nationwide analysis showing only 5.4%of patients with colon obstruction undergoing stent *** underutilization could be due to perceived increase risk of complications with stent *** To review long-and short-term clinical success of SEMS use for colonic obstruction at our *** We retrospectively reviewed all the patients who underwent colonic SEMS placement over aeighteen year period (August 2004 through August 2022) at our academic center. Demographicsincluding age, gender, indication (malignant and benign), technical success, clinical success,complications (perforation, stent migration), mortality, and outcomes were *** three patients underwent colon SEMS over an 18-year period. Fifty-five cases were formalignant indications, 8 were for benign conditions. The benign strictures included diverticulardisease stricturing (n = 4), fistula closure (n = 2), extrinsic fibroid compression (n = 1), and ischemicstricture (n = 1). Forty-three of the malignant cases were due to intrinsic obstruction from primaryor recurrent colon cancer;12 were from extrinsic compression. Fifty-four strictures occurred on theleft side, 3 occurred on the right and the rest in transverse colon. The total malignant case (n = 55)procedural success rate was 95% vs 100% for benign cases (P = 1.0, NS). Overall complication ratewas significantly higher for benign group: Four complications were observed in the malignantgroup (stent migration, restenosis) vs 2 of 8 (25%) for benign obstruction (1-perforation, 1-stentmigration) (P = 0.02). When stratifying complications of perforation and stent migration there wasno significant difference between the two groups (P = 0.14, NS).CONCLUSIONColon SEMS remains a worthwhile option for colonic obstruction rela

关键词： Colon cancer Obstruction malignancy Stricture Self-expandable metal stent Stent migration

Quality of Life in Ovarian-Cancer Patients Receiving Chemotherapy

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Journal of Cancer Therapy 2020年第11期11卷 695-714页

作者： Tohmina akhter Shahana Pervin Annekathryn Goodman Department of Gynaecologic Oncology National Institute Cancer Research and Hospital Dhaka Bangladesh Division of Gynecologic Oncology Massachusetts General Hospital Boston MA USA

Background: Ovarian cancer accounts for 4% of cancers occurring in women and ranks first in gynecological cancer mortality. Maintaining and improving quality of life is an important goal of cancer treatment. The toxicities of cancer treatment particularly chemotherapy can impact an individual’s wellbeing. Objective: Assessment of quality of life among ovarian cancer patients receiving chemotherapy. Method: A descriptive study was conducted among 202 patients with ovarian cancer treated at the National Institute of Cancer Research and Hospital in Bangladesh. Ethical approval was received from the ethics committee of NICRH. Data was collected using the EORTC QLQC30 questionnaire and the ovarian cancer specific EORTC QOL OV-28 module. Functional, symptomatic and global variables were scored and analyzed by SPSS. Multiple linear regressions determined the effects of predictor variables and correlation of the global health status with other variables. Results: 48.6% of patients were ages 41 to 50 years. The mean score of global health status was 55.77. Deteriorating emotional function, distressing physical and psychological symptoms, sexual dysfunction and financial difficulties adversely affect the quality of life. Their correlation with global health status was strongly significant (P value -0.604;p

关键词： Quality of Life EORTC QLQ C30 EORTC QOL OV-28 Ovarian Cancer Chemotherapy Bangladesh