Opposing interactions between <i>homothorax</i> and <i>Lobe</i> define the ventral eye margin of <i>Drosophila</i> eye

Singh, Amit,Tare, Meghana,Kango-Singh, Madhuri,Son, Won-Seok,Cho, Kyung-Ok,Choi, Kwang-wook Elsevier 2011 Developmental biology Vol.359 No.2

<P><B>Abstract</B></P><P>Patterning in multi-cellular organisms involves progressive restriction of cell fates by generation of boundaries to divide an organ primordium into smaller fields. We have employed the <I>Drosophila</I> eye model to understand the genetic circuitry responsible for defining the boundary between the eye and the head cuticle on the ventral margin. The default state of the early eye is ventral and depends on the function of <I>Lobe (L)</I> and the Notch ligand <I>Serrate (Ser)</I>. We identified <I>homothorax (hth)</I> as a strong enhancer of the <I>L</I> mutant phenotype of loss of ventral eye. Hth is a MEIS class gene with a highly conserved Meis-Hth (MH) domain and a homeodomain (HD). Hth is known to bind Extradenticle (Exd) via its MH domain for its nuclear translocation. Loss-of-function of <I>hth</I>, a negative regulator of eye, results in ectopic ventral eye enlargements. This phenotype is complementary to the <I>L</I> mutant phenotype of loss-of-ventral eye. However, if <I>L</I> and <I>hth</I> interact during ventral eye development remains unknown. Here we show that (i) <I>L</I> acts antagonistically to <I>hth</I>, (ii) Hth is upregulated in the <I>L</I> mutant background, and (iii) MH domain of Hth is required for its genetic interaction with L, while its homeodomain is not, (iv) in <I>L</I> mutant background ventral eye suppression function of Hth involves novel MH domain-dependent factor(s), and (v) nuclear localization of Exd is not sufficient to mediate the Hth function in the <I>L</I> mutant background. Further, Exd is not a critical rate-limiting factor for the Hth function. Thus, optimum levels of L and Hth are required to define the boundary between the developing eye and head cuticle on the ventral margin.</P> <P><B>Highlights</B></P><P>► We study the genetic mechanism involved in generation of head versus eye boundary during organogenesis in flies. ► <I>homothorax (hth)</I> acts antagonistically to the <I>Lobe</I> (<I>L</I>, PRAS40 homolog) in the ventral eye. ► L interacts with alternative spliced variant of Hth that encodes Meis-Hth (MH) domain. ► Optimum level of <I>L</I> and <I>hth</I> define boundary between eye and the head cuticle on ventral margin. ► Extradenticle (Exd) is not a critical rate limiting factor in L and Hth interaction.</P>

A High Power Density Three Phase AC-DC Converter for More Electric Aircraft (MEA)

Amit K Singh,Pritam Das,S K Panda 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

This paper presents matrix topology (3 x 1) based isolated three phase AC-DC converter suitable for aircraft systems. A novel modulation scheme based on Space Vector Modulation (SVM) is proposed to convert three phase line frequency AC into high frequency AC. The direct conversion of three phase line frequency AC into single phase high frequency AC removes the mandatory DC link capacitor which improves the power density and reliability of the system. Moreover, a variable frequency control is proposed for regulating the output voltage for different loading condition. The switching scheme for the converter is explained in detail and subsequently, the steady state analysis of converter is presented. An example converter of input 120 Vrms (3-phase), 400 Hz to output 28 V DC with an output power of 3:3 kW is designed. Comprehensive simulation is carried out using MATLAB Simulink and PSIM based software platform and results are discussed.

Switching Antibiotics Production On and Off in Actinomycetes by an IclR Family Transcriptional Regulator from Streptomyces peucetius ATCC 27952

( Amit Kumar Chaudhary ),( Bijay Singh ),( Sushila Maharjan ),( Amit Kumar Jha ),( Byung Gee Kim ),( Jae Kyung Sohng ) 한국미생물 · 생명공학회 2014 Journal of microbiology and biotechnology Vol.24 No.8

Doxorubicin, produced by Streptomyces peucetius ATCC 27952, is tightly regulated by dnrO, dnrN, and dnrI regulators. Genome mining of S. peucetius revealed the presence of the IclR (doxR) type family of transcription regulator mediating the signal-dependent expression of operons at the nonribosomal peptide synthetase gene cluster. Overexpression of doxR in native strain strongly repressed the drug production. Furthermore, it also had a negative effect on the regulatory system of doxorubicin, wherein the transcript of dnrI was reduced to the maximum level in comparision with the other two. Interestingly, the overexpression of the same gene also had strong inhibitory effects on the production of actinorhodin (blue pigment) and undecylprodigiosin (red pigment) in Streptomyces coelicolor M145, herboxidiene production in Streptomyces chromofuscus ATCC 49982, and spinosyn production in Saccharopolyspora spinosa NRRL 18395, respectively. Moreover, DoxR exhibited pleiotropic effects on the production of blue and red pigments in S. coelicolor when grown in different agar media, wherein the production of blue pigment was inhibited in R2YE medium and the red pigment was inhibited in YEME medium. However, the production of both blue and red pigments from S. coelicolor harboring doxR was halted in ISP2 medium, whereas S. coelicolor produced both pigmented antibiotics in the same plate. These consequences demonstrate that the on and off production of these antibiotics was not due to salt stress or media compositions, but was selectively controlled in actinomycetes.

How Electroconvulsive Therapy Works?: Understanding the Neurobiological Mechanisms

Amit Singh,Sujita Kumar Kar 대한정신약물학회 2017 CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE Vol.15 No.3

Electroconvulsive therapy (ECT) is a time tested treatment modality for the management of various psychiatric disorders. There have been a lot of modifications in the techniques of delivering ECT over decades. Despite lots of criticisms encountered, ECT has still been used commonly in clinical practice due to its safety and efficacy. Research evidences found multiple neuro-biological mechanisms for the therapeutic effect of ECT. ECT brings about various neuro-physiological as well as neuro-chemical changes in the macro- and micro-environment of the brain. Diverse changes involving expression of genes, functional connectivity, neurochemicals, permeability of blood-brain-barrier, alteration in immune system has been suggested to be responsible for the therapeutic effects of ECT. This article reviews different neurobiological mechanisms responsible for the therapeutic efficacy of ECT.

Thermokinetics behavior of epoxy adhesive reinforced with low viscous aliphatic reactive diluent and nano-fillers

Amit Kumar Singh,Bishnu Prasad Panda,Smita Mohanty,Sanjay Kumar Nayak,Manoj Kumar Gupta 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.11

The current study reports the effect of low viscous aliphatic reactive diluent (RD), MWCNT and VGCF on the curing kinetics of amine cured epoxy adhesive system employing non-isothermal differential scanning calorimetric (DSC) technique. Non-isothermal DSC thermograms of epoxy adhesive were studied at various heating rates: 5, 10 and 15 oC/min. The decrease in the exothermic peak height with the introduction of MWCNTs and VGCFs was taken as proof of the acceleration effect of nano-fillers on the epoxy-amine curing reaction. Also, increased Tonset, TP and ΔHcurs values were observed for epoxy/RD adhesive system at all heating rates. The value of activation energy (Ea) was determined using Kissinger and Flynn-Wall-Ozawa methods. Experimental results showed that the addition of 10 wt% RD increased the Ea from 60 to 63 kJ/mol on account of the reduced viscosity, allowing better contact of resin with the curing agent. Furthermore, MWCNTs have an accelerating effect on the cure kinetics that does not change the autocatalytic cure reaction mechanism of epoxy resin. It was also found that the addition of MWCNT and VGCF decreases the overall degree of conversion, as evident with lower ΔHcure and Ea of the cured adhesive when compared with epoxy/RD system. The dependency of Ea on degree of conversion ranging from α =0.1 to 0.9was also investigated. The two normalized functions y(α) and z(α) were also considered in order to study the complex curing mechanism. The kinetic parameters m, n and lnA were obtained by using two parameter autocatalytic Sestak-Berggren model. The curves revealed good agreement between experimentally determined and theoretically obtained MWCNT/VGCF reinforced epoxy adhesive systems.

Empirical equation and experimental validation of shear parameters for high strength concrete (HSC)

Brijesh Singh,Ojha P N,Patel Vikas,Trivedi Amit,Singh Abhishek 아시아콘크리트학회 2021 Journal of Asian Concrete Federation Vol.7 No.2

With many benefits of the high strength concrete (HSC) the more brittle behaviour that leads to sudden failure makes it important for proper understanding of its behaviour and safe and efficient estimation of capacities. Research on the behaviour of HSC has been extensively carried out since last decade. HSC has higher tensile strength hence a higher cracking shear can be expected. This paper analyzes the different international standards available for estimating concrete’s component of shear strength for reinforced cement concrete (RCC) beam. Different important factors mainly strength in compression, steel reinforcement (dowel action), ratio of shear span and depth, size effect i.e. depth along with the aggregate type (density of concrete) contributing to shear stress (Tc) of concrete has been also analyzed and thereafter, an equation has been proposed to compute or predict Tc value for concrete of both normal and higher grade or strength. The proposed equation has been validated by experimental results wherein 12 RCC beams (with and without reinforcement for shear) were cast and tested to fail in shear. The experimental results validated the proposed equation with considerable factor of safety keeping in view the sudden and brittle nature of failure in concrete in case of shear.

Impregnated Active Carbon-Shelf Life Studies and Its Evaluation Against Cyanogen Chloride with and without Canister

Singh, Beer,Saxena, Amit,Srivastava, Avanish Kumar,Dubey, Devendra Kumar,Gupta, Arvind Kumar Korean Carbon Society 2007 Carbon Letters Vol.8 No.4

Samples of active carbon of $1150\;m^2/g$ surface area were impregnated with ammoniacal salts of copper, chromium and silver, with and without triethylenediamine. The samples of impregnated carbon were aged at $50^{\circ}C$, with and without 90% RH (relative humidity), for a little more than one year and chemically evaluated periodically. Initially copper (II) and chromium (VI) reduced very fast in the samples in humid atmosphere to the extent of 30% and 60% respectively in four months. These values were found to be unaffected by the presence of triethylenediamine (TEDA) indicating that the chemical did not retard the reduction process of chromium (VI) and copper (II). However, in the absence of humidity the reduction of the impregnants was significantly less (10-12%, w/w) in four months. It was quite evident; therefore, that the moisture was mainly responsible for the reduction of chromium (VI) and copper (II) species in impregnated carbons. The prolonged ageing of the samples with and without triethylenediamme after four months with and without humid atmosphere showed that the extent of reduction of chromium (VI) was very low, i.e. 5-10% and of copper (II) was 2-25%. Silver is not reduced due to carbon, as it remained unchanged in concentration on storage. The impregnated carbon samples (100 g) without triethylenediamine, which were aged at room temperature for 5 years in absence of humidity and unaged when evaluated against cyanogen chloride (CNCl) at a concentration of 4 mg/L and airflow rate of 30 lpm showed a high degree of protection (80- 110 minutes).

Quantification of the secondary metabolites by HPTLC, analgesic and antipyretic activity evaluation of Ficus racemosa L. leaves

Amit Kumar,Amrita Mishra,Arun Kumar Mishra,Harpreet Singh 경희대학교 융합한의과학연구소 2019 Oriental Pharmacy and Experimental Medicine Vol.19 No.1

There have been no reports of simultaneous quantification of kaempferol and quercetin in Ficus racemosa L. Objective of the present work included to perform extraction using petroleum ether (PEE) and ethanol (EE), to perform preliminary phytochemical test, quantitative estimation of phytochemicals and simultaneous estimation of kaempferol and quercetin in Ficus racemosa L. using high performance thin layer chromatography (HPTLC) method and to assess the analgesic and antipyretic activity of the extracts. PEE and EE obtained from cold maceration technique. Extracts were subjected to qualitative test and estimated quantitatively. Extracts were applied on silica gel G 60 F254 plate; solvent-Toluene: Chloroform: Acetone 4.5:4.5:1 (v/v) and scanned at 254 nm. The extracts were also subjected to analgesic activity (hot plate method and tail immersion method) and antipyretic (Brewer’s yeast induced pyrexia model and Lipopolysaccharide induced pyrexia mode) activity. Findings of preliminary phytochemical test and quantitative estimation of phytochemicals confirms the presence of flavonoids in both the extracts (PEE and EE). The amount of flavonoids in PEE and EE were found to be 24.58 ± 0.60 mg/100 g and 21.01 ± 0.58 mg/100 g respectively. HPTLC system resulted well resolved bands for quercetin (Rf 0.38) and kaempferol (Rf 0.55). The validated HPTLC method was found suitable for kaempferol and quercetin quantification in Ficus racemosa L. Hot plate reaction time response was improved in a dose-dependent manner in a group of rats treated with PEE suggesting its analgesic potential. In view of analgesic potential by tail immersion method, PEE (400 mg/kg b.w.) showed no significant difference in tail flick reaction time as shown by standard treated animal (Aspirin 100 mg/kg b.w.). The findings of antipyretic activity suggested that PEE (400 mg/kg b.w.) have no significant difference in treating pyrexia when compared with Paracetamol (100 mg/kg). PEE (400 mg/kg b.w.) was found to be most potent. It may be due to the presence of comparatively high amount of flavonoids in PEE confirmed by the preliminary phytochemical test, quantitative estimation of phytochemicals and HPTLC quantification the PEE was found to be more effective when compared to EE.

Energy Budget Based Multiple Attribute Decision Making (EB-MADM) Algorithm for Cooperative Clustering in Wireless Body Area Networks

Amit Choudhary,M. Nizamuddin,Manish Kumar Singh,Vibhav Kumar Sachan 대한전기학회 2019 Journal of Electrical Engineering & Technology Vol.14 No.1

A wireless network of biosensor nodes, attached to different parts of the patient body, is termed as Wireless Body Area Network (WBAN). WBANs offer a real-time data monitoring platform for biological health parameters like blood pressure, heart rate, and glucose level etc. Low-power consumption is an essential WBAN design requirement due to limited power resources of biosensor nodes. Present work proposes the design of low power, clustering based data routing protocol for WBANs. Proposed protocol incorporates a novel “Energy Budget based Multiple Attributes Decision Making Algorithm (EB-MADM)” for dynamic cluster head selection. The algorithm selects an optimum node as cluster head which has the higher residual energy level and performs data routing at the cost of least network residual energy loss. EB-MADM selects a new cluster head for each transmission round and distributes cluster head load evenly among cluster nodes. It results in enhanced network lifetime. Proposed protocol incorporates another low power technique termed as “Cooperative effort of cluster nodes”. This technique saves node transmission energy by prohibiting redundant data from transmission. The proposed protocol is simulated using MATLAB tool and the performance results are compared with existing WBAN protocols. Proposed protocol shows better performance in terms of network lifetime, stability period, throughput, and propagation delay.

Automatic extraction of similar poetry for study of literary texts: An experiment on Hindi poetry

Amit Prakash,Niraj Kumar Singh,Sujan Kumar Saha 한국전자통신연구원 2022 ETRI Journal Vol.44 No.3

The study of literary texts is one of the earliest disciplines practiced around the globe. Poetry is artistic writing in which words are carefully chosen and arranged for their meaning, sound, and rhythm. Poetry usually has a broad and profound sense that makes it difficult to be interpreted even by humans. The essence of poetry is Rasa, which signifies mood or emotion. In this paper, we propose a poetry classification-based approach to automatically extract similar poems from a repository. Specifically, we perform a novel Rasa-based classification of Hindi poetry. For the task, we primarily used lexical features in a bag-of-words model trained using the support vector machine classifier. In the model, we employed Hindi WordNet, Latent Semantic Indexing, and Word2Vec-based neural word embedding. To extract the rich feature vectors, we prepared a repository containing 37717 poems collected from various sources. We evaluated the performance of the system on a manually constructed dataset containing 945 Hindi poems. Experimental results demonstrated that the proposed model attained satisfactory performance.