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>

Concept Explication: At the Core of It All

S. Shyam Sundar,Saraswathi Bellur,Hui Min Lee 한국언론학회 2024 Asian Communication Research Vol.21 No.1

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

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.

The Effect of Distraction-Resisting Forces on the Tibia During Distraction Osteogenesis :

Shyam, Ashok K,Song, Hae-Ryong,An, Hyonggin,Isaac, Dileep,Shetty, Gautam M,Lee, Seok Hyun Journal of Bone and Joint Surgery 2009 Journal of bone and joint surgery Vol.91 No.7

<P>BACKGROUND: Distraction-resisting forces that are generated during distraction osteogenesis can be responsible for complications, including a lag effect on fibular distraction leading to a tibiofibular distraction difference, tibial axial deviation, and distraction at the proximal and distal tibiofibular joints. We investigated the nature of distraction-resisting forces by studying their correlation with these parameters. METHODS: One hundred and eleven tibial lengthening procedures in sixty-three patients were chosen. Seventy-six segments underwent lengthening with an Ilizarov ring fixator, and thirty-five segments had lengthening over an intramedullary nail. Serial radiographs were evaluated with regard to the amounts of tibiofibular distraction difference, proximal tibiofibular joint distraction, distal tibiofibular joint distraction, tibial axial deviation, and heel malalignment. Clinically, laxity at the knee was evaluated and fibular head instability was assessed. Variations in all of these parameters were evaluated with respect to tibiofibular joint fixation, etiology, skeletal maturity, lengthening over an intramedullary nail, and amount of lengthening. RESULTS: The mean tibiofibular distraction difference was 19.1 +/- 10.6 mm (range, 2 to 51 mm), the mean proximal tibiofibular joint distraction was 10.1 +/- 6.8 mm (range, 0 to 33 mm), and the mean tibial valgus angulation was 8.7 degrees +/- 4.4 degrees . At the time of the latest follow-up, twenty-eight segments (25%) had lateral knee joint laxity at 30 degrees of knee flexion and eight segments (7%) had fibular head subluxation at 90 degrees of knee flexion. Twenty-four (86%) of the twenty-eight cases of knee laxity were observed in skeletally immature patients. The tibiofibular distraction difference, proximal tibiofibular joint distraction, and tibial valgus angulation were significantly greater in the group without fixation of the proximal tibiofibular joint. A significant decrease in the tibial valgus angulation and knee laxity was found in patients with lengthening over an intramedullary nail. In the intramedullary nail group, after fixation of the proximal tibiofibular joint, the tibiofibular distraction difference and the proximal tibiofibular joint distraction decreased; however, the proportion of cases with clinically important tibial valgus angulation (>10 degrees ) increased significantly. CONCLUSIONS: Fixing both tibiofibular joints with a single Ilizarov wire decreases proximal tibiofibular joint distraction; however, more secure fixation would help to decrease the prevalence of delayed knee laxity. When tibial lengthening is performed over an intramedullary nail, avoiding proximal tibiofibular joint fixation will limit tibial valgus angulation. Limiting lengthening to <25% will decrease the proportion of cases with knee laxity, and limiting lengthening to <50% will significantly limit tibial valgus angulation.</P>

Memristance Drift Avoidance with Charge Bouncing for Memristor-based Nonvolatile Memories

Shyam Prasad Adhikari,김형석,공배선,Leon O. Chua 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.61 No.9

A charge bouncing solution to avoid the undesirable drift in the programmed memory during readout of memristor-based non-volatile memory is proposed. Memristor memory can be programmed by strong programming signals, and the programmed memristance can be readout by weak readout signals. Though readout signals are weak compared to programming signals, readout charge is accumulated over time and leads to an undesirable drift of the operating point. This causes error in the programmed memory. Memristance drift is an important problem for practical utilization of memristors as memory. The only way presented so far to avoid drift is by converting input signals to doublets but un-ideal doublet signals still cause drifting problem. In the proposed method, drift is avoided with a capacitor in such a way that all the charge injected to the memristor during readout is stored in a capacitor, and bounced back through the memristor after completing the readout. Experimental results showing an excellent recovery from the temporal memristance drift using singlet pulses rather than the conventionally used doublet pulses for memristive memory readout are also presented.

Influence of Energy Restriction and Pre-incubation Holding Period of Eggs on Fertility and Hatchability in Aged Broiler Breeders

Shyam Sunder, G.,Vijaya Kumar, Ch.,Panda, A.K.,Rama Rao, S.V.,Raju, M.V.L.N. Asian Australasian Association of Animal Productio 2010 Animal Bioscience Vol.23 No.2

The effects of controlled energy restriction and duration of pre-incubation egg holding on fertility, hatchability and hatch losses were evaluated in aged broiler breeders (64 wk). The energy (ME) required for maintenance, activity, growth and anticipated egg production was calculated and offered to a control group (283-471 kcal/kg) from 21-64 weeks of age. In three other groups, ME was quantitatively reduced either by 20% (SER; severe energy restriction) or 10% (MER; moderate energy restriction) and increased by10% (EEF; excess energy feeding) over the control group (CER; controlled energy restriction). Each diet was offered to 130 pullets in individual cages, and the quantity of ME increased with age. At the end of 64 weeks, fertile eggs were collected from each dietary group for 11 consecutive days and grouped under 4 holding periods based on the length of storage (2, 5, 8 or 11 d). The influence of energy regimes, egg holding intervals and their interaction was evaluated on fertility, hatch losses and hatchability. Broiler breeders maintained on SER regime (231-419 kcal/d) produced maximum number of eggs (993) followed by MER (819), CER (624) and EEF (438) during the 11-day period. The percent fertility and hatchability was significantly (p$\leq$0.05) higher in SER and MER groups compared to CER and EEF. However, energy regimes did not influence the loss in egg weight during pre-incubation storage, shell weight, shell thickness or hatch losses as dead germs and dead in shell. The improvement in hatchability in SER and MER groups appeared to be closely related to higher fertility and lower embryonic mortality. Holding of eggs for 11 days showed a linear loss in egg weight with the length of storage, but did not influence the fertility and hatch losses. The percent hatchability on eggs set was maximum when storage period was restricted to 5 days. The interaction between energy regimes and egg holding periods exhibited better hatchability results with SER regime when eggs were held for 5 days. Response to MER was not different from SER. It was obvious that energy restriction during production period had a positive influence on egg number, fertility and hatchability in aged breeders. At 64 weeks of age, holding of fertile eggs for 5 days prior to incubation was adequate for optimum hatchability in breeders.

2D Visual Features based Vehicle Detection

Shyam Prasad Adhikari(샴 아디카리),Sangmin Sim(심상민),hyongsuk Kim(김형석) 제어로봇시스템학회 2009 제어로봇시스템학회 합동학술대회 논문집 Vol.2009 No.12

This paper presents a monocular vehicle detection system using a combination of visual features like shadow underneath the vehicle, horizontal edges, symmetry and intensity, and not so rigid perspective constrains. The initial estimate of the vehicle position is provided by the horizontal edges along with shadow, which is further utilized for fast symmetry detection using edge pixels only. A narrow region is thus obtained where a final search gives a bounding box around a likely vehicle. Preliminary simulation results revealed good performance of the vehicle detection system.

Metal–Organocatalytic Tandem Azide Addition/Oxyamination of Aldehydes for the Enantioselective Synthesis of β‐Amino α‐Hydroxy Esters

Shyam, Pranab K.,Jang, Hye‐,Young WILEY‐VCH Verlag 2014 EUROPEAN JOURNAL OF ORGANIC CHEMISTRY Vol.2014 No.9

<P>The tandem reaction of ,-unsaturated aldehydes with trimethylsilyl azide and 2,2,6,6-tetramethylpiperidin-1-yloxy in the presence of chiral amines and iron complexes as the catalysts in a one-pot reaction enantioselectively afforded -azido -oxyaminated aldehydes. Further synthetic modification of the product afforded -amino -hydroxy esters in good yields with good diastereo- and enantioselectivities.</P>

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.