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Defence Technology（防务技术） 2016年第5期12卷 380-387页

作者： S.V.S. Narayana MURTY Sushant K. MANWATKAR E Ramesh narayanan Material Characterization Division Materials and Metallurgy Group Vikram Sarabhai Space Centre Trivandrum 695 022 India

Maraging steels have excellent combination of strength and toughness and are extensively used for a variety of aerospace applications. In one such critical application, this steel was used to fabricate shear screws of a stage separation system in a satellite launch vehicle. During assembly preparations, one of the shear screws which connected the separation band and band end block has failed at the first thread. Microstructural analysis revealed that the crack originated from the root of the thread and propagated in an intergranular mode. The failure is attributed to combined effect of stress and corrosion leading to stress corrosion cracking.

关键词： M250 grade maraging steel Shear screw Separation system Mermen band Stress corrosion cracking

Life threatening vitamin B_(12) deficiency:will timely screening make a difference?

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World Journal of Gastroenterology 2000年第3期6卷 456-457页

作者： T.S.Dharmarajan S. Lakshmi narayanan Rajiv D. Poduval Chief Division of GeriatricsDirectorGeriatric Medicine Fellowship Program Our Lady of Mercy University Medical Center600 E 233~(rd)StreetBronxNY 10466 Resident Internal Medicine Our Lady of Mercy Medical Center Chief Medical Resident Internal Medicine Our Lady of Mercy Medical Center

INTRODUCTION While Vit.B12 deficiency is common,with aprevalence of about 15% in the elderly,andrecommendations for treatment available,detectionof deficiency at the pre-clinical stage by appropriatescreening does not always take *** report isan example of life threatening Vit.B12 deficiencydiagnosed at age 56,with the onset of Vit.B12depletion likely to have begun in the

关键词： vitamin B12 deficiency/therapy anemia sickle cell gastric mucosa biopsy anemia pernicious toxicity

Is routine use of transanastomotic tube justified in the repair of esophageal atresia?

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World Journal of Pediatrics 2017年第6期13卷 584-587页

作者： Sarath Kumar narayanan Arun Preeth Vazhiyodan Prathap Somnath Arun Mohanan Department of Pediatric Surgery Institute of Maternal and Child HealthGovernment Medical CollegeKozhikodeKeralaIndia

Background:Transanastomotic feeding tube (TAFT) is commonly used for post-operative enteral nutrition after esophageal atresia (EA)/tracheoesophageal fistula (TEF) *** purpose of this study is to analyze the therapeutic implications of avoiding a TAFT and its impact on the outcomes ***:The medical data of 33 inpatients with EA/TEF type C repair from 2009 to 2014 were retrospectively *** were divided into two groups for comparison based on the usage of TAFT during the repair:TAFT-(without) and TAFT+ (with) groups,without *** groups were compared statistically for post-operative complications and ***:Eighteen neonates were males and 15 females,with an average birth weight of 2.43±0.43 kg and a mean gestational age of 36.15 *** (57.5%) in the TAFT-group and 14 (42A%) were in the TAFF+ *** post-operative complications,need for dilatations,duration of total parenteral nutrition (TPN) and length of hospital stay were similar in both *** incidence of pneumonitis was significantly higher in the TAFT+ ***:By avoiding a TAFT,there is no increase in complication rates nor does it entail a prolonged period of ***,not using a TAFT may have the advantage of reducing incidence of aspiration and consequent pneumonifis.

关键词： esophageal atresia tracheo-esophageal fistula transanastomotic tube

Identifying strategic maintenance capacity for accidental damage occurrence in aircraft operations

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Journal of Management Analytics 2019年第1期6卷 30-48页

作者： Prasobh narayanan Wim J.C.Verhagen V.S.Viswanath Dhanisetty Delft University of Technology DelftNetherlands

Airline operators face accidental damages on their fleet of aircraft as part of operational *** occurrences are hard to predict;consequently,the approach towards repairing accidental damage is reactive in aircraft maintenance ***,by aggregating occurrence data and predicting future occurrence rates,it is possible to predict future long-term(strategic)demand for maintenance *** this paper,a novel approach for integration of reliability modelling and inventory control is ***,the concept of a base stock policy has been translated to the maintenance slot capacity problem to determine long-term cost-optimal *** has been modelled using a superposed Non-homogeneous Poisson Process(NHPP).A case study has been performed on damage data from a fleet of Boeing 777 *** results prove the feasibility of adopting an integrated approach towards strategic capacity identification,using real-life data to predict future damage occurrence and associated maintenance slot requirements.

关键词： aircraft maintenance strategic capacity identification stochastic process inventory control

Recurrent isochromosome 21 and multiple abnormalities in a patient suspected of having acute myeloid leukemia with eosinophilic differentiation—a rare case from South India

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Chinese Journal of Cancer 2012年第1期31卷 45-50页

作者： Sangeetha Vijay Santhi Sarojam Sureshkumar Raveendran Vani Syamala Sreeja Leelakumari Geetha narayanan Sreedharan Hariharan Division of Cancer Research Regional Cancer CentreMedical CollegeThiruvananthapuramKerala 695011India Division of Medical Oncology Regional Cancer CentreMedical CollegeThiruvananthapuramKerala 695011India

Acute myeloid leukemia (AML) is a phenotypically heterogeneous disorder. The M4 subtype of AML is frequently associated with the cytogenetic marker inversion 16 and/or the presence of eosinophilia. Blast crisis is the aggressive phase of the triphasic chronic myeloid leukemia (CML), which is a disease with Philadelphia (Ph) chromosome as the major abnormality. In the present study, we report a 76-year-old patient suspected of having AML with eosinophilic differentiation (AML-M4), which in clinical tests resembles CML blast crisis with multiple chromosomal abnormalities. Isochromosome 21 [i(21)(q10)] was the most recurrent feature noted in metaphases with 46 chromosomes. Ring chromosome, tetraploid endoreduplication, recurrent aneuploid clones with loss of X chromosome, monosomy 17, monosomy 7, and structural variation translocation (9;14) were also observed in this patient. Fluorescent in situ hybridization (FISH) confirmed the absence of Ph chromosome. This report shows how cytogenetic analyses revealed atypical structural aberrations in the M4 subtype of AML.

关键词：慢性粒细胞白血病嗜酸性粒细胞等臂染色体染色体异常髓细胞急性细胞遗传学分析复发

Pure and Mg-doped self-assembled ZnO nano-particles for the enhanced photocatalytic degradation of 4-chlorophenol

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Journal of Environmental Sciences 2013年第10期25卷 2157-2167页

作者： N.Clament Sagaya Selvam S.narayanan L.John Kennedy J.Judith Vijaya Catalysis and Nanomaterials Research Laboratory Department of Chemistry Loyola College Materials Division School of Advanced Sciences Vellore Institute of Technology UniversityChennai Campus

A novel self-assembled pure and Mg doped ZnO nano-particles （NPs） were successfully synthesized by a simple low temperature co-precipitation method. The prepared photocatalysts were characterized by X-ray diffraction, high resolution scanning electron mi- croscopy, high resolution transmission electron microscopy, diffuse reflectance spectroscopy and photoluminescence （PL） spectroscopy. The results indicated that the prepared photocatalysts showed high crystallinity with a uniform size distribution of the NPs. The degradation of cholorphenols is highly mandatory in today＇s scenario as they are affecting the environment adversely. Thus, the photocatalytic degradation of 4-chlorophenol （4-CP）, a potent endocrine disrupting chemical in aqueous medium was investigated by both pure and Mg-doped ZnO NPs under UV-light irradiation in the present study. The influence of the Mg content on the structure, morphology, PL character and photocatalytic activity of ZnO NPs were investigated systematically. Furthermore,the effect of different parameters such as 4-CP concentration, photocatalyst amount, pH and UV-light wavelength on the resulting photocatalytic activity was investigated.

关键词： Mg-doped ZnO nanoparticles photocatalyst photocatalytic degradation 4-chlorophenol

Integrating biochar and bacteria for sustainable remediation of metal-contaminated soils

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Biochar 2023年第1期5卷 1098-1116页

作者： Peng Ouyang Mathiyazhagan narayanan Xiaojun Shi Xinping Chen Zhenlun Li Yongming Luo Ying Ma College of Resources and Environment Southwest UniversityChongqing 400716China Division of Research and Innovation Department of BiotechnologySaveetha School of EngineeringSaveetha Institute of Medical and Technical ScienceChennai 602105Tamil NaduIndia Key Laboratory of Soil Environment and Pollution Remediation Institute of Soil ScienceChinese Academy of SciencesNanjing 210008China

Due to anthropogenic activities,heavy metal(HM)pollution in soils has increased,resulting in severe ecological problems and posing a constant threat to human *** various remediation methods,bacterial remediation is a relatively clean,efficient,and minimally negative ***,bacterial agents face multiple environmental stresses,making them challenging to achieve long-lasting and stable restoration *** address this issue,supportive organic substances such as biochar can be added to the soil with *** to bibliometric studies,integrating biochar and bacteria is extensively researched and widely used for HM-contaminated soil *** integrating biochar and bacteria,heavy metals in the soil can be remediated,and soil conditions can be improved over *** can also better promote plant growth or contribute effectively to phytoremediation processes when assisted by ***,the remediation agents integrating biochar and bacteria are still some distance away from large-scale use because of their high cost and possible environmental ***,further discussion on the interaction between biochar and bacteria and the integration approach,along with their remediation efficiency and environmental friendliness,is needed to achieve sustainable remediation of HM-contaminated soils by integrating biochar and *** paper discusses the potential mechanisms of biochar-bacteria-metal interactions,current advancements in biochar-bacteria combinations for HM-contaminated soil treatment,and their application in sustainable remediation,analyzes the interaction between biochar and bacteria and compares the remediation effect of different ways and feedstocks to integrate biochar and ***,future directions of biochar-bacteria combinations are presented,along with evidence and strategies for improving their commercialization and implementation.

关键词： Biochar Heavy metals Bioremediation Plant-beneficial bacteria Soil pollution

Environmentally assisted cracking resistance of Al-Cu-Li alloy AA2195 using slow strain rate test in 3.5% NaCl solution

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Transactions of Nonferrous Metals Society of China 2017年第2期27卷 241-249页

作者： R.GHOSH A.VENUGOPAL P.RAMESH narayanan S.C.SHARMA P.V.VENKITAKRISHNAN Materials and Metallurgy Group Materials and Mechanical EntityVikram Sarabhai Space CentreThiruvananthapuram-695022KeralaIndia

The general corrosion and environmental cracking resistances of Al-Cu-Li alloy AA2195 were investigated in 3.5% NaCl environment and compared with those of another high strength alloy AA2219. The general corrosion resistance of these alloys was examined using immersion corrosion and potentiodynamic polarization tests, while the stress corrosion cracking （SCC） resistance was evaluated by slow strain rate test （SSRT） method. The tested samples were further characterized by SEM-EDS and optical profilometry to study the change in corrosion morphology, elemental content and depth of corrosion attack. The reduction in ductility was used as a parameter to evaluate the SCC susceptibility of the alloys. The results indicated that the corrosion resistance of AA2195 alloy was better than that of AA2219 alloy as it exhibited lower corrosion rate, along with lower pit depth and density. However, the SCC index （εNaCl/εair） measured was greater than 0.90, indicating good environmental cracking resistance of both the alloys. Detailed fractography of the failed samples under SEM？EDS, in general, revealed a typical ductile cracking morphology for both the alloys.

关键词： Al-Cu-Li alloy stress corrosion cracking fractography potentiodynamic polarization

Microstructure and texture evolution in AZ31 magnesium alloy during caliber rolling at different temperatures

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Journal of Magnesium and Alloys 2017年第3期5卷 340-347页

作者： Abhishek Tripathi S.V.S.Narayana Murty P.Ramesh narayanan Department of Metallurgical Engineering and Materials Science Indian Institute of Technology BombayMumbai 400076India Materials Characterisation Division Materials and Metallurgy GroupVikram Sarabhai Space CentreTrivandrum 695022India

Magnesium alloy AZ31 was caliber rolled at different temperatures viz.523K,573K,623K,673K and 723K imposing a total cumulative reduction of 92%and a cumulative strain of *** associated microstructure and texture evolution were studied using Electron Back Scattered Diffraction(EBSD)and X-ray macro-texture observations *** refinement was observed in all the caliber rolled bars indicating the occurrence of dynamic *** parameter and texture index were used to study the evolution of *** doubling of the yield strength at room temperature was observed by caliber rolling at a temperature of *** improvement in mechanical properties was explained on the basis of the fine grain microstructures and suitable development of crystallographic *** on the present study,warm caliber rolling can be used as a good production method for obtaining long bars of high strength magnesium alloy AZ31.

关键词： Magnesium alloy AZ31 Microstructure Caliber rolling Texture

Current status of nitrous oxide use in pediatric patients

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World Journal of Clinical Pediatrics 2022年第2期11卷 93-104页

作者： Nishkarsh Gupta Anju Gupta R M Vishnu narayanan Department of Onco-Anesthesiology and Palliative Medicine AIIMSNew Delhi 110029DelhiIndia Department of Anesthesiology Pain Medicine and Critical CareAIIMSNew Delhi 110029DelhiIndia

Nitrous oxide is one of the most commonly used inhalational anesthetic agents used in *** is a cost-effective,pleasant,safe,and versatile anesthetic agent with many desirable properties like good quality analgesia,decreased awareness,accelerated induction and recovery from anesthesia,and reduced utilization of other expensive inhalational agents with potential cost *** use of nitrous oxide has been questioned by a lot of studies and case reports perceiving its adverse systemic,hematological,immune,and neurologic adverse ***,the literature in the recent past has tried to resolve the controversies related to its *** concerns over an increase in cardiovascular complications and mortality following nitrous oxide use have been negated by recent ***,its use in certain vulnerable populations like children with cobalamin and folate deficiency or defects in their metabolic pathways remains a cause of concern for its toxic *** this narrative review,we aim to discuss the pharmacological properties of nitrous oxide,the potential advantages and drawbacks of the use of nitrous oxide in children,address the neurodevelopmental and other systemic effects,and throw light on the evidence regarding the safety of nitrous oxide use and its current role in pediatric procedural sedation and anesthesia *** literature related to its use in the pediatric population for painful procedures and surgeries has been summarized.

关键词： Child Nitrous oxide Vitamin B12 Vulnerable populations Anesthesiology Anesthetics Folic acid Metabolic networks and pathways