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Eco-friendly reduced graphene oxide for the determination of mycophenolate mofetil in pharmaceutical formulations

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Journal of Pharmaceutical Analysis 2018年第2期8卷 131-137页

作者： Prashanth S.Narayan Nagappa L.Teradal seetharamappa Jaldappagari Ashis K.satpati Department of Chemistry Karnatak University Analytical Chemistry Division Bhabha Atomic Research Centre

Graphene oxide(GO) was synthesized and characterized by scanning electron microscopy(sEM), energy dispersive X-ray spectroscopy(EDX), atomic force microscopy(AFM), X-ray diffraction(XRD), Fourier transform-infrared spectroscopy(FT-IR) and thermogravimetric analysis(TGA). GO was then electrochemically reduced and used for electrochemical study of mycophenolate mofetil(MMF). The electrochemically reduced graphene oxide(ERGO) film on glassy carbon electrode(GCE) showed enhanced peak current for electrooxidation of MMF. MMF exhibited two irreversible oxidation peaks at 0.84 V(peak a_1)and 1.1 V(peak a_2). Effects of accumulation time, pH and scan rate were studied and various electrochemical parameters were calculated. A differential pulse voltammetric method was developed for the determination of MMF in bulk samples and pharmaceutical formulations. Linear relationship was observed between the peak current and concentration of MMF in the range of 40 nM–15 μM with a limit of detection of 11.3 nM. The proposed method is simple, sensitive and inexpensive and, hence, could be readily adopted in clinical and quality control laboratories.

关键词： Mycophenolate mofetil Electroreduced graphene oxide Electrochemical sensor Analytical application

Workability studies in Forming of sintered Fe-0.35CPowder Metallurgy Preform During Cold Upsetting

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Journal of Iron and steel Research(International) 2011年第12期18卷 71-78页

作者： S.Narayan A Rajeshkannan school of Engineering and Physics Faculty of ScienceTechnology and EnvironmentUniversity of the South Pacific(Laucala Campus)

An experimental investigation on the workability behaviour of sintered Fe-0.35C steel preforms under cold upsetting,have been studied in order to understand the influence of aspect ratio and lubrication condition on the workability process.The above mentioned powder metallurgy sintered preform with constant initial theoretical density of 84% of different aspect ratios,namely,0.4 and 0.6 respectively were prepared using a suitable die-set assembly on a 1 MN capacity hydraulic press and sintered for 90 min at 1200 ℃.Each sintered preform was cold upset under nil/no and graphite frictional constraint,respectively.Under the condition of triaxial stress densification state,axial stress,hoop stress,hydrostatic stress,effective stress and formability stress index against axial strain relationship was established and presented in this work.Further more,attained density was considered to establish formability stress index and various stress ratio parameters behaviour.

关键词： powder metallurgy failure analysis plastic behaviour workability

Influence of Carbon Content on strain Hardening Behaviour of sintered Plain Carbon steel Preforms

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Journal of Iron and steel Research(International) 2011年第9期18卷 33-40页

作者： S.Narayan A Rajeshkannan Mechanical Engineering The University of the South PacificLaucala Campus

Complete experimental investigation on the instantaneous strain hardening behaviour of powder metallurgy （P/M） preforms of pure iron, Fe 0.35%C, Fe-0.75%C and Fe-1.1%C was carried out. The strain hardening be haviour of the above-mentioned P/M sintered steel preforms with aspect ratio of 0.4 under triaxial stress state condition was determined by cold upsetting under nil/no and graphite lubricant conditions. The instantaneous strain hardening value （ni）, strength coefficient （Ki）, and the stress as a function of strain and densification were obtained and analyzed. Furthermore, a relation was obtained from a semi-log plot of stress against relative density and analyzed to study the hardening behaviour owing to densification as stress was a function of induced strain as well as densification in the P/M materials.

关键词： strain hardening exponent density hardening exponent strength coefficient densification triaxial stress

Workability Behaviour of Fe-C-Mo steel Preforms During Cold Forging

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Journal of Iron and steel Research(International) 2013年第9期20卷 126-130页

作者： S.Narayan A Rajeshkannan K s Pandey s shanmugam school of Engineering and Physics Faculty of ScienceTechnology and EnvironmentUniversity of South Pacific Department Metallurgical and Materials Engineering National Institute of Technology Department of Mechanical Engineering National Institute of Technology

A systematic method to construct the workability diagram for powder metallurgy （P/M） materials has been proposed. Preforms of Fe-0.8 %C, Fe-0.8% C-1% Mo and Fe-0.8 % C 2 % Mo were prepared to the relative den-sity of 0.86 with two different geometries through primary operations of P/M processes. Each sintered preform was cold upset forged with incremental compressive loading of 0.04 MN under three different lubricant conditions till a visible crack appeared at the free surface. Oyane＇s fracture criterion was used to develop a theory to study P/M prod-ucts. The least square method was used to determine the constants in fracture criteria and these equations were even- tually used to construct workability diagram. It is found that the proposed method was well in agreement with the experimental results.

关键词： workability diagram yield criterion formability

The relationship between age,acceptable noise level,and listening effort in middle-aged and older-aged individuals

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中华耳科学杂志:英文版 2023年第4期18卷 220-229页

作者： Hemanth narayan shetty suma Raju sanjana singh s Department of Audiology JSS Institute of Speech and HearingMysuruKarnatakaIndia Department of speech-Language Pathology JSS Institute of Speech and HearingMysuruKarnatakaIndia

Objective:The purpose of the study was to evaluate listening effort in adults who experience varied annoyance towards noise.Materials and methods:Fifty native Kannada-speaking adults aged 41e68 years participated.We evaluated the participant's acceptable noise level while listening to speech.Further,a sentence-final wordidentification and recall test at 0 dB sNR(less favorable condition)and 4 dB sNR(relatively favorable condition)was used to assess listening effort.The repeat and recall scores were obtained for each condition.Results:The regression model revealed that the listening effort increased by 0.6%at 0 dB sNR and by 0.5%at 4 dB sNR with every one-year advancement in age.Listening effort increased by 0.9%at 0 dB sNR and by 0.7%at 4 dB sNR with every one dB change in the value of Acceptable Noise Level(ANL).At 0 dB sNR and 4 dB sNR,a moderate and mild negative correlation was noted respectively between listening effort and annoyance towards noise when the factor age was controlled.Conclusion:Listening effort increases with age,and its effect is more in less favorable than in relatively favorable conditions.However,if the annoyance towards noise was controlled,the impact of age on listening effort was reduced.Listening effort correlated with the level of annoyance once the age effect was controlled.Furthermore,the listening effort was predicted from the ANL to a moderate degree.

关键词： Listening effort Acceptable noise level Cognitive reservoir Repeat and recall task

Introduction of the special issue on COVID-19 and the financial and economic systems

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Financial Innovation 2022年第1期8卷 1403-1406页

作者： Paresh Kumar narayan Monash Business school Monash UniversityMelbourneAustralia

A large number of submissions were received in response to this call for paper on the theme of COVID-19 and the financial and economic systems.Naturally,the COVID-19 pandemic has dominated much of the recent finance and economics literature.This call for paper was motivated by early special issues on the COVID-19 business and economics themes such as those published by sha and sharma(2020)and sharma and sha(2020,2021).This editorial has two parts.In the first part I summarize the key outcomes from each of the papers.In the second part,I identify an agenda for future research that has emanated from this special issue papers.

关键词： motivated finance systems.

Mercury emissions and partitioning from Indian coal-fired power plants

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Journal of Environmental sciences 2021年第2期33卷 28-33页

作者： Hridesh Agarwalla Rabi narayan senapati Tarit Baran Das Coal Minerals&Heauy Metal Research Group CSIR-Central Institute of Mining and Furl ResearchDhcmbad-82810India

In India coal combustion is the single largest source of emission of mercury which is a widespread persistent global toxicant,travelling across international borders through air and water.As a party to the Minamata convention,India aims to monitor and reduce Hg emissions and stricter norms are introduced for mercury emissions from power plants(30μg/Nm 3 for flue gas in stack).This paper presents the results obtained during the experimental studies performed on mercury emissions at four coal-fired and one lignite-fired power plants in India.The mercury concentration in the feed coal varied between 0.12-0.27 mg/Kg.In the mercury mass balance,significant proportion of feed coal mercury has been found to be associated with fly ash,whereas bottom ash contained very low mercury.80%-90%of mercury was released to air through stack gas.However,for circulating fluidised bed boiler burning lignite,about 64.8%of feed mercury was found to get captured in the fly ash and only 32.4%was released to air.The mercury emission factor was found to lie in the range of 4.7-15.7 mg/GJ.

关键词： Coal combustion Emission Mercury Flue gas Thermal power plant

Toll-like receptors and hepatitis C virus infection

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Hepatobiliary & Pancreatic Diseases International 2021年第6期20卷 521-529页

作者： Yang Gao narayan Nepal shi-Zhu Jin Department of Gastroenterology and Hepatology The Second Affiliated Hospital of Harbin Medical UniversityHarbin 150086China

Background:Hepatitis C virus(HCV)infection is a worldwide issue.However,the current treatment for hepatitis C has many shortcomings.Toll-like receptors(TLRs)are pattern recognition receptors involved in HCV infection,and an increasing number of studies are focusing on the role of TLRs in the progression of hepatitis C.Data sources:We performed a Pub Med search up to January 2021 with the following keywords:hepatitis C,toll-like receptors,interferons,inflammation,and immune evasion.We also used terms such as single-nucleotide polymorphisms(sNPs),susceptibility,fibrosis,cirrhosis,direct-acting antiviral agents,agonists,and antagonists to supplement the query results.We reviewed relevant publications analyzing the correlation between hepatitis C and TLRs and the role of TLRs in HCV infection.Results:TLRs 1–4 and 6–9 are involved in the process of HCV infection.When the host is exposed to the HCV,TLRs,as important participants in HCV immune evasion,trigger innate immunity to remove the virus and also promote inflammation and liver fibrosis.TLR gene sNPs affect hepatitis C susceptibility,treatment,and prognosis.The contribution of each TLR to HCV is different.Drugs targeting various TLRs are developed and validated,and TLRs can synergize with classic hepatitis C drugs,including interferon and direct-acting antiviral agents,constituting a new direction for the treatment of hepatitis C.Conclusions:TLRs are important receptors in HCV infection.Different TLRs induce different mechanisms of virus clearance and inflammatory response.Although TLR-related antiviral therapy strategies exist,more studies are needed to explore the clinical application of TLR-related drugs.

关键词： Hepatitis C Toll-like receptors Interferons Inflammation Immune evasion

Temporal cues and the effect of their enhancement on speech perception in older adults——A scoping review

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Journal of Otology 2016年第3期11卷 95-101页

作者： Hemanth narayan shetty All India Institute of speech and Hearing

Temporal envelope is a low frequency amplitude modulation conveying segmental and suprasegmental information during speech perception.Unfortunately,we seldom find ourselves in completely quiet listening environments and noise,commonly found in the surrounding environment,obscures both the fine structure cues and partly the temporal envelope cues in speech.Available temporal content of speech emanating from noise is often enough to convey required information in normal hearing individuals.However,the case is different in older adults(with and without hearing loss) who lack such capabilities due to the impairment in temporal processing.This calls attention of a researcher to delineate the importance of temporal enhancement of speech in improving speech perception.There are many temporal envelope strategies available in the literature,but each one has its own lacunae.An envelope enhancement by a deep band modulation(DBM) is found to be beneficial for those individuals who have had a temporal processing impairment.The reason could be attributed to the 15 dB enhancement in the temporal envelope bandwidth between 3 and 30 Hz,extracted from each channel,which significantly increases the modulation depth such that masking of a consonant by a vowel is minimized.Additionally,output of deep band modulated speech is rescaled such that its duration increases and it provides relatively easy access to the word of the lexicon.Thus,in the near future,with more experiments related to DBM algorithm,it can be utilized in the rehabilitative devices to lessen the impact of the temporal processing impairment.

关键词： Temporal Envelope Modulation Older adults