Surface Design Using Laser Rapid Manufacturing for Ti64-Hopeite Orthopedic Implants

Ashish Das,Mukul Shukla 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.7

Although hopeite bioceramic coatings have already proven efective for achieving better osseointegration and antibacterialcharacter, but the detachment of hopeite coatings during implanting of coated implants can negatively afect the hopeitebioactivity in the physiological environment. To overcome this issue, the present research work proposes a new processroute of laser rapid manufacturing (LRM) for depositing hopeite coatings with the metallurgical bond. Microstructure, phasecomposition, microhardness, antibacterial efcacy, and bioactivity were evaluated using scanning electron microscope, X-raydifraction, Vickers microhardness tester, fuorescence-activated cell sorting technique, simulated body fuid immersion testrespectively. The promising results obtained from these characterizations and testing establishes a new process route LRMas an efective alternative to deposit multifunctional hopeite coatings on metallic prosthetic–orthopedic implants.

Genetic Transformation of Pigeonpea (Cajanus cajan L.) and Screening Transgenic Progenies Based on Lateral Root Inhibition

Alok Das,Manoj Kumar,Arvind Kumar Singh,Alok Shukla,Jamal Ansari,Subhojit Datta,Narendra Pratap Singh 한국작물학회 2016 Journal of crop science and biotechnology Vol.19 No.4

Production of transgenic pigeonpea is becoming increasingly important, but the methods currently employed in production and subsequent screening still requires improvement. Here, we describe Agrobacterium-mediated genetic transformation of pigeonpea with reporter uidA (gus) gene and selectable marker, neomycin phospho-transferase (nptII) gene. Histochemical assay demonstrate localization of gus activity in cells and transformed plants. Overall, a transformation frequency of 0.33% was achieved using the protocol. Grafting of in vitro-regenerated healthy shoots indicates higher survival percent (72.6%), when stock and scion are of the same variety. Seeds harvested from primary transgenic plants can be screened based on lateral root inhibition strategy. Approximately 87% of the screened T1 plants were found to be PCR positive. In conclusion, in vitro grafting of transgenic pigeonpea shoots leads to better plant establishment and screening based on lateral root inhibition leads to quick identification of positive segregants.

The Clinical, Etiological, and Demographic Profile of Children Aged 1 to 14 Years with Seizures Attending a Tertiary Care Hospital in Gwalior District, India: A Cross-Sectional Study

Vasudevan Mani,Ghanshyam Das,Arvind Gupta,Ajay Gaur,Durgesh Shukla 대한소아신경학회 2024 대한소아신경학회지 Vol.32 No.2

Purpose: The clinical profile of seizures among children exhibits ethnic and geographical variations. The objective of this study was to examine the clinical, etiological, and demographic profiles of childhood seizures. Methods: This was a hospital-based, cross-sectional study. Data were collected on the socio-demographic profile, details of the clinical presentation of seizure episodes, past history of meningitis, and neuroimaging (i.e., computed tomography [CT] scans), as well as the history of risk factors. Numbers, percentages, the chi-square test, and the Fisher exact test statistic were calculated. A P value of <0.05 was considered significant. Results: This study included 102 patients, of whom 82 experienced generalized tonic-clonic seizures (GTCS) and the remaining 20 had focal seizures. The most common age at presentation was between 1 and 4 years (55.9%). Approximately 70.0% of the children experienced postictal confusion and drowsiness, 38.2% had fever or sleep deprivation, and 25.5% suffered from headaches or vomiting. Postictal confusion and drowsiness were significantly more prevalent in children with GTCS (76.8%) compared to those with focal seizures (45.0%). Cerebral edema was the most common abnormality detected on CT scans in children with GTCS (n=6). Conclusion: Younger age, neonatal brain insult, and family history were found to be associated with a higher risk of seizure episodes. Postictal confusion and drowsiness were identified as the most common clinical features. Postictal confusion and drowsiness were significantly more prevalent in GTCS compared to focal seizures. Cerebral edema was the most common abnormality observed in GTCS on CT neuroimaging.

Fast Marx Generator for Directly Driving a Virtual Cathode Oscillator

Biswajit Adhikary,Anurag Shyam,R. Shukla,S. K. Sharma,P. Banerjee,P. Deb,T. Prabaharan,R. Das,B. K. Das 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.61

This paper presents the design, development and testing of a fast, compact hybrid-type Marx generator which is suitable to directly drive a high-power microwave producing virtual cathode oscillator. The developed Marx generator has an open circuit voltage of 300 kV, a pulse width of 640 ns (FWHM) and a rise time of 200 ns. The fast rise time is achieved by reducing the inductance of the discharge path with the help of specially designed spark gaps. The Marx generator operates in open air now, but will soon be placed in a container with insulation that will help to charge the stage capacitors to their maximum voltage rating repeatedly, it will also help to reduce the rise time further by bringing the return path close thus reducing the inductance. The Marx generator has six stages, and all stages are charged to same polarity, with 1.8 kJ being stored at full charge. The operational characteristics, such as the impedance, inductance, current- delivering capacity, rise time, etc; of the developed Marx generator are determined experimentally. A detailed study on the effect of loading on the generator and its performance is also conducted. The overall size of the generator without its container is 0.8m in length, 0.45m in height and 0.35m in width.

Design and Modeling of a Capacitor Bank Power Supply for Fast Charging

Surender Kumar Sharma,Pankaj Deb,R. Shukla,P. Banerjee,T. Prabaharan,R. Das,B. Das,B. Adhikary,A. Shyam 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.61

Power supplies used in pulsed power applications are rugged, and the capacitor bank charges rapidly. The capacitor bank is fully charged to the rated voltage in a minimum time so as to reduce the dielectric stress on the capacitors and to increase their life. When the capacitor bank is discharged in the load much Electromagnetic Interference (EMI) and Electromagnetic Pulse (EMP) due to high currents discharges is generated, which can damage the electronic circuitry in the power supply if proper shielding & isolation are not provided to it. We have designed and fabricated a compact, rugged and low-cost high voltage (HV) power supply for a 114-kJ, 40-kV capacitor bank. The power supply consists of a high voltage transformer (5.25 kVA, 230 V/35 kV, 50 Hz), a high voltage diode (Semikron Make PIV 110 kV, 150 mA) and a charging resistor placed in a tank filled with oil. The charging resistors value is selected after a PSPICE simulation of the charging circuit for different values of the charging resistor. The charging current is limited with the selected resistor so that it does not exceed the current limit of the HV transformer & diode. The input voltage to the high voltage transformer is given through autotransformer, which rotates from 0 ?230 volts in 40 sec with a single-phase synchronous motor. The capacitor bank is charged to 40 kV in a minute after that, the power supply is decoupled from the capacitor bank by using a pneumatic decoupling switch, then the capacitor bank's switch is triggered to deliver the capacitor bank's energy to the load. Control and protection in the power supply is provided for its safe operation. The monitoring of charging voltage is done with a digital display meter with fiber optic isolation by using a V-F and then F-V converter in order to provide electrical isolation.

Empirical model for estimating dengue incidence using temperature, rainfall, and relative humidity: a 19-year retrospective analysis in East Delhi

Vishnampettai G. Ramachandran,Priyamvada Roy,Shukla Das,Narendra Singh Mogha,Ajay Kumar Bansal 한국역학회 2016 Epidemiology and Health Vol.38 No.-

OBJECTIVES: Aedes mosquitoes are responsible for transmitting the dengue virus. The mosquito lifecycle is known to be influenced by temperature, rainfall, and relative humidity. This retrospective study was planned to investigate whether climatic factors could be used to predict the occurrence of dengue in East Delhi. METHODS: The number of monthly dengue cases reported over 19 years was obtained from the laboratory records of our institution. Monthly data of rainfall, temperature, and humidity collected from a local weather station were correlated with the number of monthly reported dengue cases. One-way analysis of variance was used to analyse whether the climatic parameters differed significantly among seasons. Four models were developed using negative binomial generalized linear model analysis. Monthly rainfall, temperature, humidity, were used as independent variables, and the number of dengue cases reported monthly was used as the dependent variable. The first model considered data from the same month, while the other three models involved incorporating data with a lag phase of 1, 2, and 3 months, respectively. RESULTS: The greatest number of cases was reported during the post-monsoon period each year. Temperature, rainfall, and humidity varied significantly across the pre-monsoon, monsoon, and post-monsoon periods. The best correlation between these three climatic factors and dengue occurrence was at a time lag of 2 months. CONCLUSIONS: This study found that temperature, rainfall, and relative humidity significantly affected dengue occurrence in East Delhi. This weather-based dengue empirical model can forecast potential outbreaks 2-month in advance, providing an early warning system for intensifying dengue control measures.