Single-Molecule Junction Conductance through Diaminoacenes

The study of electron transport through single molecules is essential to the development of molecular electronics. Indeed, trends in electronic conductance through organic nanowires have emerged with the increasing reliability of electron transport measurements at the single-molecule level. Experimental and theoretical work has shown that tunneling distance, HOMO-LUMO gap and molecular conformation influence electron transport in both saturated and pi-conjugated nanowires. However, there is relatively little experimental data on electron transport through fused aromatic rings. Here we show using diaminoacenes that conductivity depends not only on the number of fused aromatic rings in the molecule, which defines the molecular HOMO-LUMO gap, but also on the position of the amino groups on the rings. Specifically, we find that conductance is highest with minimal disruption of aromaticity in fused aromatic nanowires.Comment: 2 pages, 3 figure

Well-being and perspective of second year MBBS students on online pharmacology classes held during COVID-19 pandemic in a tertiary care teaching hospital

Background: COVID-19 pandemic shifted all the classroom teaching to virtual online platforms. The overnight change in the teaching structure posed serious challenges especially for medical education. This study aims to assess the well-being of medical students undergoing online medical education during COVID-19 pandemic and their perspective on online pharmacology classes.Methods: World health organization (WHO-5) well-being index was used to assess well-being of students. An internally validated questionnaire was used to assess student’s perspective on online pharmacology classes. The questionnaire was administered to eligible consenting students online through Google forms. The data obtained was analysed by SPSS software.Results: The mean wellness score (%) for all participants, (n=118) was 48.87%. The mean wellness score for males (58.67%) was higher than for females (42.41%). The average score for overall benefit of conducting online pharmacology classes was 3.32 out of 5. Objectively assessed online interactions like formative assessment, polls and quiz were rated higher than subjective interactions like debate.Conclusions: COVID-19 pandemic has caused massive disruption in the life of many people. In our study, we report a decreased well-being score in medical students attending virtual classes. The findings on well-being of students have implications on planning redressal mechanism in such extreme situations. Our analysis of student’s perspective about online interactions has implications beyond online classes. Some of the interactions can be instituted into regular curriculum increasing the student’s participation

Semantic Retrieval of Relevant Sources for Large Scale Virtual Documents

AbstractThe term big data has come into use in recent years. It is used to refer to the ever-increasing amount of data that organizations are storing, processing and analyzing. An Interesting fact with bigdata is that it differ in Volume, Variety, Velocity characteristics which makes it difficult to process using the conventional Database Management System. Hence there is a need of schema less Management Systems even this will never be complete solution to bigdata analysis since the processing has no focus on the semantic information as they consider only the structural information. Content Management System like Wikipedia stores and links huge amount of documents and files. There is lack of semantic linking and analysis in such systems even though this kind of CMS uses clusters and distributed framework for storing big data. The retrieved references for a particular article are random and enormous. In order to reduce the number of references for a selected content there is a need for semantic matching. In this paper we propose framework which make use of the distributed parallel processing capability of Hadoop Distributed File System (HDFS) to perform semantic analysis over the volume of documents (bigdata) to find the best matched source document from the collection source documents for the same virtual document

Relativistic coupled-cluster calculations of 20^{20}Ne, 40^{40}Ar, 84^{84}Kr and 129^{129}Xe: correlation energies and dipole polarizabilities

We have carried out a detailed and systematic study of the correlation energies of inert gas atoms Ne, Ar, Kr and Xe using relativistic many-body perturbation theory and relativistic coupled-cluster theory. In the relativistic coupled-cluster calculations, we implement perturbative triples and include these in the correlation energy calculations. We then calculate the dipole polarizability of the ground states using perturbed coupled-cluster theory.Comment: 10 figures, 6 tables, submitted to PR

On the influence of spatial heterogeneity on an internal boundary layer at a short fetch

Surface layer meteorological data collected at a coastal site, at Vasco-Da-Gama (15°21′N, 73°51′E, 58.5m MSL) (13–18 July, 2002) with prevailing southwesterly surface winds are analyzed to study the characteristics of internal boundary layer at a short fetch using an instrumented tower (9 m). The spectral and turbulence characteristics of wind are compared with earlier measurements made at a comparatively homogeneous terrain and the standards available in literature. The study show the smaller eddies in the vertical velocity spectrum attains equilibrium with the underlying surface at a short fetch itself and follows spectral similarity. However, this is not followed by longitudinal and transverse velocity spectra under unstable as well as stable condition

SYNTHESIS AND IN-VITRO STUDY OF NOVEL (Z)-1-BENZHYDRYL-4-CINNAMYLPIPERAZINE DERIVATIVES AS POTENTIAL ANTICANCER AGENTS

Objective: The objective of this study was to synthesize Z- 1-benzhydryl-4-cinnamylpiperazines by novel stereo selective synthetic method and evaluation of their anticancer properties.Methods: A series of novel (Z)-1-benzhydryl-4-cinnamylpiperazine derivatives (9a-j) were synthesized, starting from benzophenones in six steps. Wittig condensation of appropriate benzyltriphenyl phosphonium halides with various 1-benzhydryl- 4-(2-ethanal) piperazines (3a-j), and column purification over silica gel afforded pure Z- 1-benzhydryl-4-cinnamylpiperazines.Results: The structures of newly synthesized compounds 9a-j were established by 1H & 13C NMR and mass spectral analysis. The anticancer potential (MTT assay) of synthesized compounds was tested against human cervical cancer (HeLa) and murine microglial (BV-2) cell lines. Results indicated that the most of the Z-derivatives exhibited moderate to good anticancer activity on both the cell lines over their E- antipodes.Conclusion: Compound 9i (cis- flunarizine) exhibited exceptionally superior activity against both HeLa and BV-2 cell lines with IC50 value of 13.23±3.51 µM and 23.1±4.12 µM respectively. Hence, this compound may be considered to be a potential lead molecule for further developmentÂ

Thioltransferase (glutaredoxin) mediates recovery of motor neurons from excitotoxic mitochondrial injury

Mitochondrial dysfunction involving electron transport components is implicated in the pathogenesis of several neurodegenerative disorders and is a critical event in excitotoxicity. Excitatory amino acid L-β-N-oxalylamino-L-alanine (L-BOAA), causes progressive corticospinal neurodegeneration in humans. In mice, L-BOAA triggers glutathione loss and protein thiol oxidation that disrupts mitochondrial complex I selectively in motor cortex and lumbosacral cord, the regions affected in humans. We examined the factors regulating postinjury recovery of complex I in CNS regions after a single dose of L-BOAA. The expression of thioltransferase (glutaredoxin), a protein disulfide oxidoreductase regulated through AP1 transcription factor was upregulated within 30 min of L-BOAA administration, providing the first evidence for functional regulation of thioltransferase during restoration of mitochondrial function. Regeneration of complex I activity in motor cortex was concurrent with increase in thioltransferase protein and activity, 1 hr after the excitotoxic insult. Pretreatment with α-lipoic acid, a thiol delivery agent that protects motor neurons from L-BOAA-mediated toxicity prevented the upregulation of thioltransferase and AP1 activation, presumably by maintaining thiol homeostasis. Downregulation of thioltransferase using antisense oligonucleotides prevented the recovery of complex I in motor cortex and exacerbated the mitochondrial dysfunction in lumbosacral cord, providing support for the critical role for thioltransferase in maintenance of mitochondrial function in the CNS

Synthesis and characterization of Nano sulphur: Exploring its potential as slow release fertilizer

Sulphur is rapidly being recognized as the fourth key nutrient for plants after nitrogen, phosphorus, and potassium. It functions in several critical metabolic and physiological processes, such as Chlorophyll synthesis, Protein synthesis, Activation of enzymes, Stress tolerance and Seed production. In this background, an attempt was made to synthesize nano sulphur fertilizers for slow release using the reverse microemulsion (water-in-oil microemulsion) technique. Cyclohexane was used as oil phase. Tween-80 and ethanol were used as surfactant and co-surfactant, respectively. Hydrochloric acid and sodium polysulfide solution acted as an aqueous phase. This technique resulted in the successful synthesis of nano sulphur fertilizer. The sulphur nano fertilizer was characterized using X-ray diffraction (XRD), Fourier-Transform infrared spectroscopy (FT-IR), Scanning electron microscope (SEM) and Thermogravimetric analysis (TGA). The XRD pattern revealed the orthorhombic nature of nano sulphur and the lattice face-centred. The FTIR spectra at 1406 cm-1 confirmed the sulphur vibrations. The microemulsion method yielded stable, uniform, spherical nano sulphur particles with dimensions ranging from 25 to 47 nm. The thermal disintegration between 117°C to 122°C in TGA graph was attributed to the sublimation of sulphur in orthorhombic crystalline form, indicating the successful synthesis of nano sulphur. A laboratory study on nano sulphur fertilizer and conventional sulphur fertilizer was studied with a Percolator reaction system to evaluate the slow release of sulphur from both fertilizers at ambient temperature. Percolation reactor experiment indicated that sulphate release from nano sulphur was longer for 42 days than gypsum amended soil which exhausted within 35 days. Hence, synthesized nano sulphur fertilizer maximizes nutrient retention, eliminates environmental nutrient loses and decreases fertilizer requirements

Stimulation and inhibition by bicarbonate of stomatal opening in epidermal strips of Commelina benghalensis

The effect of 0 to 100 μM bicarbonate on stomatal opening in epidermal strips of Commelina benghalensis was examined in the presence or absence of fusicoccin in light or darkness. Low concentrations of bicarbonate (up to 10 μM in the absence and 25 μM in presence of fusicoccin) stimulated stomatal opening while higher concentrations inhibited. The enhancement of opening by low concentrations of bicarbonate and phosphoenol pyruvate (PEP), and prevention of bicarbonate stimulation by malate or oxaloacetate suggested PEP carboxylase as a CO2 sensor in the guard cells. However, the inhibition of PEP carboxylase did not completely suppress the opening caused by fusicoccin. The action of fusicoccin therefore appears to involve a site other than CO2 fixation, presumably through the stimulation of proton excretion

Association of Kinesthetic and Read-Write Learner with Deep Approach Learning and Academic Achievement

Background: The main purpose of the present study was to further investigate study processes, learning styles, and academic achievement in medical students.Methods: A total of 214 (mean age 22.5 years) first and second year students - preclinical years - at the Asian Institute of Medical Science and Technology (AIMST) University School of Medicine, in Malaysia participated.  There were 119 women (55.6%) and 95 men (44.4%).   Biggs questionnaire for determining learning approaches and the VARK questionnaire for determining learning styles were used.  These were compared to the student’s performance in the assessment examinations.Results: The major findings were 1) the majority of students prefer to study alone, 2) most students employ a superficial study approach, and 3) students with high kinesthetic and read-write scores performed better on examinations and approached the subject by deep approach method compared to students with low scores.  Furthermore, there was a correlation between superficial approach scores and visual learner’s scores.Discussion: Read-write and kinesthetic learners who adopt a deep approach learning strategy perform better academically than do the auditory, visual learners that employ superficial study strategies.   Perhaps visual and auditory learners can be encouraged to adopt kinesthetic and read-write styles to enhance their performance in the exams