Simultaneous co-immobilization of enzyme and a redox mediatorin polypyrrole film for the fabrication of an amperometricphenol biosensor

Rajesh,S.S. Pandey,W. Takashima,K. Kaneto 한국물리학회 2005 Current Applied Physics Vol.5 No.2

A conducting polypyrrole lm has been prepared on indium tin oxide coated glass plate by electropolymerization of pyrrole in anaqueous solution of enzyme, tyrosinase (PPO), and a redox mediator potassium hexacyanoferrate (II). The enzyme retains its bio-activity well within the polymer lm. Phenol concentration in aqueous solution was quantitatively estimated by monitoring the elec-tron exchange occurring in redox mediator within the polymer matrix i.e. direct reduction of Fe (III) to Fe (II) ion at +0.12V vs. Ag/AgCl. The results of amperometric response measurements conducted on enzyme electrode (PPO/Fe2+/PPY/ITO) show a sensitivityof 0.33 AM. 1 cm. 2 and a linear response range of 4.5107.4l M for phenol in aqueous medium. The electrode exhibits a responsetime of about 80 second and is stable for 4 months at 4.C..

A new tyrosinase biosensor based on covalent immobilizationof enzyme on N-(3-aminopropyl) pyrrole polymer film

Rajesh,K.Kaneto 한국물리학회 2005 Current Applied Physics Vol.5 No.2

A conducting polymer film of N-amino substituted pyrrole monomer has been prepared for covalent immobilization of enzyme for biosensing applications, illustrated by tyrosinase (PPO).The tyrosinase enzyme retains its bioactivity when being immobilized on N-substituted pyrrole polymer film by covalent bonding.The enzyme electrode was characterized by UV.Vis and infrared spectroscopy.Phenolic compounds were quantitatively estimated by the direct electrochemical reduction of enzymatically liberated quinone species at 0.2 V vs. Ag/AgCl. The results of amperometric response measurements conducted on enzyme electrode show sensitivity of 57.6, 71.4 and 45.8 mAM1cm2 and a linear response range of 1.8.170.2, 1.3.110.1 and 2.1.168 lM for phenol, catechol and p-cresol, respectively. The biosensor exhibits a lowest detection limit of 0.9, 0.7 and 1.1 lM, for phenol, catechol and p-cresol, respectively and a period of stable sensitivity of 3 months at 4.5 C.

Effect of Preoperative Vitamin D Levels on Functional Performance after Total Knee Arthroplasty

Rajesh Navin Maniar,Aniket Machindra Patil,Adit Rajesh Maniar,Bharat Gangaraju,Jaivardhan Singh 대한정형외과학회 2016 Clinics in Orthopedic Surgery Vol.8 No.2

Background: Low vitamin D levels affects muscle function. Vitamin D and calcium deficiency cause osteomalacic myopathy and poor functional recovery after hip fractures. The relationship of vitamin D and functional performance after total knee arthroplasty (TKA) is not previously reported. Methods: Influence of vitamin D on functional performance before and after TKA was reviewed retrospectively in 120 patients. Of these, 64 had vitamin D deficiency (25-hydroxy vitamin D < 30 ng/mL) preoperatively. All 120 patients received vitamin D oral supplementation postoperatively. Functional parameters including Western Ontario and McMaster Osteoarthritis Index (WOMAC), Short-Form Health Survey questionnaire, and Knee Society Score were assessed pre- and postoperatively at 3 months. Results: Preoperative function was significantly lower in osteoarthritic patients with vitamin D deficiency (WOMAC score; p = 0.040), but at 3 months all functional scores were similar. Conclusions: We concluded that vitamin D deficiency has a negative effect on function in knee osteoarthritic patients. However, postoperative vitamin D supplementation can lead to functional recovery in these patients. Thus, TKA should not be delayed in vitamin D deficient patients; rather supplementation in the postoperative period is preferable to achieve comparable functional outcome at 3 months to patients with vitamin D sufficiency.

A novel hybrid technique to treat flush mesenteric arterial occlusion in acute-on-chronic mesenteric ischemia

Rajesh Girdhardas Mundhada,Atul Dharmaraj Rewatkar,Aishwarya Atul Rewatkar,Anju Rajesh Mundhada,Nikita Navin Chandak 소화기인터벤션의학회 2023 International journal of gastrointestinal interven Vol.12 No.1

Acute mesenteric occlusion is a life-threatening condition with a significant mortality rate and requires prompt diagnosis and revascularization using open repair, a hybrid procedure, or endovascular intervention. The open approach is associated with significant morbidity and mortality, while endovascular procedures are done by the antegrade or retrograde open mesenteric stent technique and have been observed to improve the prognosis and outcomes of mesenteric ischemia. We report three cases of acute-on-chronic mesenteric ischemia secondary to occlusion with failed percutaneous mesenteric artery stenting. They were successfully treated using a novel hybrid technique, without the need for mesenteric arteriotomy or subsequent arterial repair.

Ratio-Cum-Product Estimators of Population Mean Using Known Population Parameters of Auxiliary Variates

Tailor, Rajesh,Parmar, Rajesh,Kim, Jong-Min,Tailor, Ritesh The Korean Statistical Society 2011 Communications for statistical applications and me Vol.18 No.2

This paper suggests two ratio-cum-product estimators of finite population mean using known coefficient of variation and co-efficient of kurtosis of auxiliary characters. The bias and mean squared error of the proposed estimators with large sample approximation are derived. It has been shown that the estimators suggested by Upadhyaya and Singh (1999) are particular case of the suggested estimators. Almost ratio-cum product estimators of suggested estimators have also been obtained using Jackknife technique given by Quenouille (1956). An empirical study is also carried out to demonstrate the performance of the suggested estimators.

<i>Marsilea</i> spp.—A novel source of lignocellulosic biomass: Effect of solubilized lignin on anaerobic biodegradability and cost of energy products

Rajesh Banu, J.,Sugitha, S.,Kannah, R. Yukesh,Kavitha, S.,Yeom, Ick Tae Elsevier 2018 Bioresource technology Vol.255 No.-

<P><B>Abstract</B></P> <P>The present study concerns the liquefying potential of an unusual source of lignocellulosic biomass (<I>Marsilea</I> spp., water clover, an aquatic fern) during combinative pretreatment. The focus was on how the pretreatment affects the biodegradability, methane production, and profitability of thermochemical dispersion disintegration (TCDD) based on liquefaction and soluble lignin. The TCDD process was effective at 12,000 rpm and 11 min under the optimized thermochemical conditions (80 °C and pH 11). The results from biodegradability tests imply that 30% liquefaction was sufficient to achieve enhanced biodegradability of about 0.280 g-COD/g-COD. When biodegradability was >30% inhibition was observed (0.267 and 0.264 g-COD/g-COD at 35–40% liquefaction) due to higher soluble lignin release (4.53–4.95 g/L). Scalable studies revealed that achievement of 30% liquefaction was beneficial in terms of the energy and cost benefit ratios (0.956 and 1.02), when compared to other choices.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Novel lignocellulosic biomass, <I>Marsilea quadrifolia</I> was exploited to get energy. </LI> <LI> First study to evaluate the effect of liquefaction and lignin on biodegradability. </LI> <LI> Energy spent to obtain 20–30% liquefaction was very low compared to others. </LI> <LI> Inhibition of biodegradability occured for samples with 35–40% liquefaction. </LI> <LI> Cost analysis reveals that achievement of 30% liquefaction was profitable. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Risk Factors and Outcomes Associated with Intraoperative Fractures during Short-Stem Total Hip Arthroplasty for Osteonecrosis of the Femoral Head

Rajesh Malhotra,Saurabh Gupta,Vivek Gupta,Vikrant Manhas 대한정형외과학회 2022 Clinics in Orthopedic Surgery Vol.14 No.1

Background: Young age in osteonecrosis of the femoral head (ONFH) demands bone-preserving, short-stem arthroplasty. Several designs including neck-preserving stems and neck-resecting, shortened, standard stems are classified as short stems. There is a paucity of literature investigating risk factors and outcomes of intraoperative complications of neck preserving, short-stem arthroplasty in ONFH. Methods: A total of 107 hips operated with METHA short-stem arthroplasty for ONFH were retrospectively evaluated. The mean age of patients was 43.7 years (range, 27–60 years). Nine patients had an intraoperative fracture. Seven hips received prophylactic cerclage wiring for poor bone quality. Patients were invited for clinical and radiological evaluation at the latest follow-up. Results: The mean follow-up of patients was 47.2 months. Significant association with intraoperative fractures and the need for prophylactic cerclage wiring were found in steroids-, alcohol-, and chronic renal failure-induced ONFH. However, patient sex, body mass index, traumatic/idiopathic ONFH, previous implant in situ , prosthesis size, and single-sitting bilateral total hip replacement (THA) were not the risk factors. All hips showed signs of osteointegration at final follow-up. No revision was done during the study period for any cause. Conclusions: METHA short-stem THA offers excellent functional and radiological outcomes in ONFH. However, precaution must be exercised in patients with steroids-, alcohol-, and renal disorders-induced ONFN due to poor bone quality and higher chances of intraoperative fractures. Also, additional measures such as the use of a high-speed burr and prophylactic cerclage wiring in ONFH may allow predictable and safe use of short stems.

Cup-Cage Construct Using Porous Cup with Burch-Schneider Cage in the Management of Complex Acetabular Fractures

( Rajesh Malhotra ),( Deepak Gautam ) 대한고관절학회 2019 Hip and Pelvis Vol.31 No.2

Purpose: Cup-cage construct technique was developed to address the massive acetabular defects during revision hip arthroplasty. Indications have extended to complex acetabular fractures with pelvic discontinuity necessitating acute total hip arthroplasty. However, its use is constrained in low socioeconomic countries due to non-availability of the original cages from Trabecular Metal Acetabular Revision System and high cost. We used a novel technique using the less expensive Burch-Schneider (BS) cage and Trabecular Metal Revision Shell (TMRS) to address the problem. Materials and Methods: We reviewed a consecutive series of 8 cases of acetabular fractures reconstructed using a ‘cup-cage construct’ technique using a BS cage along with a TMRS. The mean age of the patients was 61.4 years. Patients were followed up for a mean period of 50.5 months (24 to 72 months). The patients were assessed clinically with Harris Hip Score and radiologically with serial X-rays. Results: All the patients were available at the latest follow up. The mean Harris Hip Score was 87.2. There was no radiological evidence of failure. One patient had dislocation two months following the surgery, which was treated by closed reduction and hip abduction brace. One patient developed an infection at 3 weeks necessitating debridement. The same patient had sciatic nerve palsy that recovered after 4 months. Conclusion: This novel technique of the cup-cage construct seems to provide a stable construct at short to midterm follow-up. However, a long-term follow up would be required.

Rare Earths Recovery from Waste Permanent Magnets (WPMs) by Hydrometallurgical Methods

( Rajesh Kumar Jyothi ),( Jin-young Lee ),( Kyeong Woo Chung ),( Jong Hyuk Jeon ) 한국폐기물자원순환학회 2022 ISSE 초록집 Vol.2022 No.-

Rare earths are a series of 17 elements (the lanthanides, yttrium, and scandium) which are key components in the current lifestyle. Those metals have multiple applications in different areas especially in the electrical and electronics fields alongside being key materials for green energy production. To recover rare earths from primary (ores) and secondary sources (scraps, spent magnets, etc.) the economically sound and most convenient technology involves liquid- liquid extraction. Several countries, such as South Korea, lack of primary sources of these important metals, therefore they must recur to recycling -or importation (fluctuating depending on the market supply and demand)- to fulfill the demand necessary for their growing high-tech industries, dedicated primarily to the manufacture of electrical and electronic items used in the daily life. In addition, after electronic and industrial goods are used they must be discarded usually in landfills, which in small countries with high population density is a great economic, social and environmental burden. The countries with the highest population densities according to the economic co-operation and development (OECD) organization records (year 2012) are South Korea, The Netherlands, Belgium, Israel, Japan, UK, Germany, Luxemburg, Italy and Switzerland (http://www.un.org/en/development/desa/population/publications/trends/wpp2012. The market trade of rare earths is a monopoly controlled by China, followed by a small supply from India, Australia, Malaysia, Brazil, USA and Russia. China’s monopoly of the RE trade can be seen as detrimental for the free economy of these goods having applications widely in the metallurgy, permanent magnets, electronics, fabrication of household items, glass, alloys, petroleum refining catalysts, among others. The major rare earth consuming industrial products are magnets 26%, metal alloys 19%, polishing 16.5%, catalysts 15%, glass/phosphors 6% and ceramics/others 5.5%, which shows the necessity of an industrial and economically feasible process to recover REEs from waste or secondary resources. The Department of Energy in the United States recognize four elements as critical due to their multiple industrial applications: neodymium, praseodymium, dysprosium and terbium. When talking about green economy, the first option that must be considered is the minimization of the consumption of the elements or the minimization of waste production. The second option to be considered is the reuse, recycling and recovery of the waste produced in the fabrication process of consumer products. Finally, the least favored option is the disposal of waste, which must overcome the landfill challenge. By reusing and recycling rare earth elements from secondary sources the national demand of these metals can be reached without consuming primary resources and having and environmental friendly process.

Computational and Experimental Simulations of the Flow Characteristics of an Aerospike Nozzle

Rajesh, G.,Kumar, Gyanesh,Kim, H.D.,George, Mathew The Korean Society of Visualization 2012 한국가시화정보학회지 Vol.10 No.1

Single Stage To Orbit (SSTO) missions which require its engines to be operated at varying back pressure conditions, use engines operate at high combustion chamber pressures (more than 100bar) with moderate area ratios (AR 70~80). This ensures that the exhaust jet flows full during most part of the operational regimes by optimal expansion at each altitude. Aero-spike nozzle is a kind of altitude adaptation nozzle where requirement of high combustion chamber pressures can be avoided as the flow is adapted to the outside conditions by the virtue of the nozzle configuration. However, the thrust prediction using the conventional thrust equations remains to be a challenge as the nozzle plume shapes vary with the back pressure conditions. In the present work, the performance evaluation of a new aero-spike nozzle is being carried out. Computational studies are carried out to predict the thrust generated by the aero-spike nozzle in varying back pressure conditions which requires the unsteady pressure boundary conditions in the computational domain. Schlieren pictures are taken to validate the computational results. It is found that the flow in the aero-spike nozzle is mainly affected by the base wall pressure variation. The aerospike nozzle exhibits maximum performance in the properly expanded flow regime due to the open wake formation.