Metal–Organocatalytic Tandem Azide Addition/Oxyamination of Aldehydes for the Enantioselective Synthesis of β‐Amino α‐Hydroxy Esters (Eur. J. Org. Chem. 9/2014)

Shyam, Pranab K.,Jang, Hye‐,Young WILEY‐VCH Verlag 2014 European Journal of Organic Chemistry Vol.2014 No.9

<P><B>The cover picture shows </B>an easy and efficient transformation of cinnamaldehyde and its derivatives to optically active β‐azido α‐oxyaminated aldehydes by the cooperation of an organocatalyst (chiral sec‐amine) and an iron catalyst. Furthermore, synthesized β‐azido α‐oxyaminated aldehydes were easily modified to afford pharmaceutically valuable β‐amino α‐hydroxy esters in three steps without loss of enantio‐ and diastereoselectivity. Details are discussed in the Short Communication by P. K. Shyam and H.‐Y. Jang on p. 1817 ff. </P>

Gait and tremor assessment for patients with Parkinson’s disease using wearable sensors

Shyam V. Perumal,산카 한국통신학회 2016 ICT Express Vol.2 No.4

Typically, subjects with Parkinson’s disease (PD) display instances of tremor at an early stage of the disease and later on develop gait impairments and postural instability. In this research, we have investigated the effect of using both gait and tremor features for an early detection and monitoring of PD. Various features were extracted from the data collected from the wearable sensors and further analyzed using statistical analysis and machine learning techniques to find the most significant features that would best distinguish between the two groups: subjects with PD and healthy control subjects. The analysis of our results shows that the features of step distance, stance and swing phases, heel and normalized heel forces contributed more significantly to achieving a better classification between the two groups in comparison with other features. Moreover, the tremor analysis based on the frequency-domain characteristics of the signal including amplitude, power distribution, frequency dispersion, and median frequency was carried out to identify PD tremor from atypical Parkinsonism tremor.

Increased ERCP volume improves cholangiogram interpretation: a new performance measure for ERCP training?

Shyam Vedantam,Sunil Amin,Ben Maher,Saqib Ahmad,Shanil Kadir,Saad Khalid Niaz,Mark Wright,Nadeem Tehami 대한소화기내시경학회 2022 Clinical Endoscopy Vol.55 No.3

Background/Aims: Cholangiogram interpretation is not used as a key performance indicator (KPI) of endoscopic retrograde cholangiopancreatography(ERCP) training, and national societies recommend different minimum numbers per annum to maintain competence. This study aimed to determine the relationship between correct ERCP cholangiogram interpretation and experience. Methods: One hundred fifty ERCPists were surveyed to appropriately interpret ERCP cholangiographic findings. There were threegroups of 50 participants each: “Trainees,” “Consultants group 1” (performed >75 ERCPs per year), and “Consultants group 2” (performed>100 ERCPs per year). Results: Trainees was inferior to Consultants groups 1 and 2 in identifying all findings except choledocholithiasis outside the intrahepaticduct on the initial or completion/occlusion cholangiogram. Consultants group 1 was inferior to Consultants group 2 in identifyingStrasberg type A bile leaks (odds ratio [OR], 0.86; 95% confidence interval [CI], 0.77−0.96), Strasberg type B (OR, 0.84; 95% CI,0.74−0.95), and Bismuth type 2 hilar strictures (OR, 0.81; 95% CI, 0.69−0.95). Conclusions: This investigation supports the notion that cholangiogram interpretation improves with increased annual ERCP casevolumes. Thus, a higher annual volume of procedures performed may improve the ability to correctly interpret particularly difficultfindings. Cholangiogram interpretation, in addition to bile duct cannulation, could be considered as another KPI of ERCP training.

Leg lengthening by distraction osteogenesis using the Ilizarov apparatus: a novel concept of tibia callus subsidence and its influencing factors

Shyam, Ashok K.,Singh, Surya Udai,Modi, Hitesh N.,Song, Hae-Ryong,Lee, Seok-Hyun,An, Hyonggin Springer-Verlag 2009 International orthopaedics Vol.33 No.6

Banana Pseudostem Sap as a Biomordant for Dyeing of Silk with Celosia Flower

Shyam Barahapurkar,Roli Purwar,Rajat Kumar Baldua 한국섬유공학회 2020 Fibers and polymers Vol.21 No.9

This research paper is focused on the dyeing of silk fabrics with a natural dye extracted from Celosia flower andbanana pseudostem sap as a biomordant. The dyeing process was carried out by three different techniques i.e. pre-, post-, andsimultaneous mordanting method. The effect of dyeing process parameters namely mordant concentration, pH, andtemperature on the dye absorption and fastness properties of dyed silk fabric have been investigated for each dyeing method. Optimal values of dyeing process parameters have been categorized based on the highest value of dye absorption in terms ofK/S value. Optimum mordant concentration was found to be 18 % for all sets of dyeing methods. The optimum pH wasexamined to be 4.5, 4.0, and 4.0 and dyeing temperature was 70 °C, 70 °C, and 65 °C for the pre-, post-, and simultaneousmordanting dyeing methods, respectively. The color fastness to light, washing, and rubbing of dyed silk fabrics wasinvestigated. Fastness values of light and rubbing showed fair-to-good fastness level, whereas the color fastness to washingwas found to be good to very good. The antibacterial activity of the banana sap mordanted and simultaneously dyed silkfabrics was evaluated. The dyed silk fabric exhibited moderate antibacterial activity against gram-positive and gram-negativebacteria.

Synthesis and Characterization of Crosslinked Transparent Poly(ester-urethane-acrylate) Containing Methyl Methacrylate

Shyam Dev Maurya,Surendra K. Kurmvanshi,Smita Mohanty,Sanjay K Nayak 한국고분자학회 2017 Macromolecular Research Vol.25 No.9

The current study deals with the synthesis of various compositions of crosslinked poly(ester-urethane-acrylate) (PEUA)/methylmethacrylate (MMA) copolymer employing free radical polymerization. Initially, (1,4-butanediol) orthophthalate (BPE) polyester polyol has been synthesized by reacting 1,4 butanediol (BDO) and phthalic anhydride (PA). Subsequently the PEUA prepolymer was formed by reacting one mole of BPE with two mole of isophorone diisocyanate (IPDI) followed by end capping with two mole of 2-hydroxyethyl methacrylate (HEMA) in the presence of dibutyltin dilaurate (DBTL) catalyst. Finally, different compositions of crosslinked PEUA/MMA copolymer were prepared by reacting the PEUA prepolymer with MMA, in the presence of 1% azobisisobutyronitrile (AIBN) (w/w) as a chain initiator. The formation of BPE, PEUA and copolymers was confirmed by Fourier transform infrared (FT-IR) and 1H NMR spectroscopy. Water uptake, mechanical, thermal and optical properties of PEUA, PMMA and their copolymers have been also investigated. The impact fractured surface morphology of copolymers was observed using scanning electron microscope (SEM). The results showed that the increased miscibility, improved mechanical and physical properties of copolymer was influenced by the crosslink density. Dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA), Haze and transparency of PEUA/MMAcopolymers were determined. The copolymer with 40wt% MMA loading exhibited optimum mechanical and physical properties with respect to the other compositions.

Automatic Method for Contrast Enhancement of Natural Color Images

Shyam Lal,A. V. Narasimhadhan,Rahul Kumar 대한전기학회 2015 Journal of Electrical Engineering & Technology Vol.10 No.3

The contrast enhancement is great challenge in the image processing when images are suffering from poor contrast problem. Therefore, in order to overcome this problem an automatic method is proposed for contrast enhancement of natural color images. The proposed method consist of two stages: in first stage lightness component in YIQ color space is normalized by sigmoid function after the adaptive histogram equalization is applied on Y component and in second stage automatic color contrast enhancement algorithm is applied on output of the first stage. The proposed algorithm is tested on different NASA color images, hyperspectral color images and other types of natural color images. The performance of proposed algorithm is evaluated and compared with the other existing contrast enhancement algorithms in terms of colorfulness metric and color enhancement factor. The higher values of colorfulness metric and color enhancement factor imply that the visual quality of the enhanced image is good. Simulation results demonstrate that proposed algorithm provides higher values of colorfulness metric and color enhancement factor as compared to other existing contrast enhancement algorithms. The proposed algorithm also provides better visual enhancement results as compared with the other existing contrast enhancement algorithms.

Thermoelastic deformation behavior of functionally graded cylindrical panels with multiple perforations

Shyam K. Chaudhary,Vishesh R. Kar,Karunesh K. Shukla Techno-Press 2023 Advances in aircraft and spacecraft science Vol.10 No.2

The present article focuses on the thermoelastic deformation behavior of inhomogeneous functionally graded metal/ceramic cylindrical shell structure with multiple perforations using 2D finite element approximation. Here, cylindrical shell structure is considered with single (1×1) and multiple (2×2, 3×3 and 4×4) perforations. The temperature-dependent elastic and thermal properties of functionally graded material are evaluated using Voigt's micromechanical material scheme via power-law function. The kinematics of the proposed model is based on the equivalent single-layer first-order shear deformation mid-plane theory with five degrees-of-freedom. Here, 2D isoparametric finite element solutions are obtained using eight-node quadrilateral elements. The mesh refinement of present finite element model is performed to confirm the appropriate number of elements and nodes for the analysis purpose. Subsequently, a comparison test is conducted to demonstrate the accuracy of present results. In later section, numerous numerical illustrations are demonstrated at different set of conditions by varying structural, material and loading parameters and that confirms the significance of various parameters such as power-law index, aspect ratio, thickness ratio, curvature ratio, number of perforations and temperature on the deformation characteristics of functionally graded cylindrical shell structure.

On-Road Succeeding Vehicle Detection using Characteristic Visual Features

Shyam Prasad Adhikari(샴아디카리),Hitek Cho(조휘택),Hyeon-Joong Yoo(유현중),Changju Yang(양창주),Hyongsuk Kim(김형석) 대한전기학회 2010 전기학회논문지 Vol.59 No.3

A method for the detection of on-road succeeding vehicles using visual characteristic features like horizontal edges, shadow, symmetry and intensity is proposed. The proposed method uses the prominent horizontal edges along with the shadow under the vehicle to generate an initial estimate of the vehicle-road surface contact. Fast symmetry detection, utilizing the edge pixels, is then performed to detect the presence of vertically symmetric object, possibly vehicle, in the region above the initially estimated vehicle-road surface contact. A window defined by the horizontal and the vertical line obtained from above along with local perspective information provides a narrow region for the final search of the vehicle. A bounding box around the vehicle is extracted from the horizontal edges, symmetry histogram and a proposed squared difference of intensity measure. Experiments have been performed on natural traffic scenes obtained from a camera mounted on the side view mirror of a host vehicle demonstrate good and reliable performance of the proposed method.

Photovoltaic properties in poly(3-alkylthiophene) based heterojunction cells

ShyamS.Pandey,KoichiRikitake,WataruTakashima,KeiichiKaneto 한국물리학회 2003 Current Applied Physics Vol.3 No.2, 3

Photocarrier generation and photovoltaic eect have been systematically studied in single layer ITO/poly(3-alkylthioph-ene)(P3AT)/Al Schottky and double layer ITO/P3AT/perylene/metal heterojunction cells. It has been found that Ohmic contactformation takes place between ITO (Au) with P3AT and Au (Ag, Al) with perylene derivatives. The double layer organic het-erojunction device shows strong rectifying behavior with the rectication ratio of 1000 (at. 2 V) and the ideality factor of 2.15. Themaximum incident photon to electron conversion eciency (IPCE) of 0.08% was found for the devices fabricated using regioregularjunction cell IPCE was more than an order of magnitude higher than that of the single layer junction of regioregular P3BT/Al.. 2002 Elsevier Science B.V. All rights reserved.