Cucurbit[8]uril Rotaxanes

The synthesis of [2]rotaxanes, each comprising a viologen core threaded through a cucurbit[8]uril (Q8, Figure 1) macrocycle and stoppered by tetraphenylmethane groups, and their binding to second guests as inclusion complexes in organic and aqueous media are described. Stoppering was observed to have little effect on binding. Chemical modification of the threaded guest was used to control solubility and binding characteristics, thus demonstrating a novel approach to making artificial receptors with readily modifiable properties

A STUDY ON COMPETENCY NEEDS ANALYSIS AND QUALITY FACTORS FOR FRESH RECRUITS

ABSTRACT "Measure what is measurable and make measurable what is not" -Galileo Galilei When quality has become the universal phenomenon especially after globalization, international corporate highly focus at the time of selection and recruitment of personnel. Multinational companies strongly believe that the quality at the entry level assures and guarantees the quality in the subsequent stages too. Companies innovate various strategies to identify and recognize the requirement competencies among fresh and potential candidates. Among all other employable criteria, communication skills ranks top. This paper makes an attempt to study the methodology and processes involved and the strategies and challenges the companies face during the exercise

Determining Protease Substrate Selectivity and Inhibition by Label-Free Supramolecular Tandem Enzyme Assays

An analytical method has been developed for the continuous monitoring of protease activity on unlabeled peptides in real time by fluorescence spectroscopy. The assay is enabled by a reporter pair comprising the macrocycle cucurbit[7]uril (CB7) and the fluorescent dye acridine orange (AO). CB7 functions by selectively recognizing N-terminal phenylalanine residues as they are produced during the enzymatic cleavage of enkephalin-type peptides by the metalloendopeptidase thermolysin. The substrate peptides (e.g., Thr-Gly-Ala-Phe-Met-NH2) bind to CB7 with moderately high affinity (K ≈ 104 M–1), while their cleavage products (e.g., Phe-Met-NH2) bind very tightly (K \u3e 106 M–1). AO signals the reaction upon its selective displacement from the macrocycle by the high affinity product of proteolysis. The resulting supramolecular tandem enzyme assay effectively measures the kinetics of thermolysin, including the accurate determination of sequence specificity (Ser and Gly instead of Ala), stereospecificity (d-Ala instead of l-Ala), endo- versus exopeptidase activity (indicated by differences in absolute fluorescence response), and sensitivity to terminal charges (−CONH2 vs −COOH). The capability of the tandem assay to measure protease inhibition constants was demonstrated on phosphoramidon as a known inhibitor to afford an inhibition constant of (17.8 ± 0.4) nM. This robust and label-free approach to the study of protease activity and inhibition should be transferable to other endo- and exopeptidases that afford products with N-terminal aromatic amino acids

An experimental study of pressure drop characteristics in vertical upward two phase and three phase flows

Master'sMASTER OF ENGINEERIN

A Cucurbit[8]uril Sponge

This paper describes a convenient approach to quantitative removal of the synthetic host cucurbit[8]uril (Q8) from aqueous mixtures using a sepharose resin coated in memantine groups to selectively sequester Q8 in the presence of competing hosts and guests. The “Q8 sponge” can separate Q8 from Q6 and reverse the Q8-mediated dimerization of peptides

Prevalence of copepod parasite (Lernaeenicus polynemi) infestation on Eleutheronema tetradactylum from Pazhayar coastal waters, southeast coast of India

Objective: To study the prevalence and mean intensity of copepod parasite Lernaeenicus polynemi infestation on Eleutheronema tetradactylum from Pazayar, Tamil Nadu, of India. southeast coast Methods: The fish was collected from Pazhayar landing centre from January to December 2012 aonf dp atrhaesiirt ebsi owmeeretr rice cmoredaesdu.rements were examined. Toal number of infected fish and total number. Results: Higher prevalence and mean intensity of infestation of 35.23% and 3.1 were respectively rbeopdoyr toefd t hdeu rhinosgt manodn stoaorgne steedas tohne odfi f2f0e1r2e.n Tt hinet epranraals iotircg ainnsfe ssutacthio anss lwiveerre asncda tttheree ddo orvsaelr athoret ae.n Ttihree highest intensity was reported to be 66 parasites in a single host. Conclusions: Due to the heavy parasitic attack the fish will suffer and its economical value or the marketability may reduce

Nanomolar Binding of Peptides Containing Noncanonical Amino Acids by a Synthetic Receptor

This paper describes the molecular recognition of phenylalanine derivatives and their peptides by the synthetic receptor cucurbit[7]uril (Q7). The 4-tert-butyl and 4-aminomethyl derivatives of phenylalanine (tBuPhe and AMPhe) were identified from a screen to have 20–30-fold higher affinity than phenylalanine for Q7. Placement of these residues at the N-terminus of model tripeptides (X-Gly-Gly), resulted in no change in affinity for tBuPhe-Gly-Gly, but a remarkable 500-fold increase in affinity for AMPhe-Gly-Gly, which bound to Q7 with an equilibrium dissociation constant (Kd) value of 0.95 nM in neutral phosphate buffer. Structure–activity studies revealed that three functional groups work in a positively cooperative manner to achieve this extraordinary stability (1) the N-terminal ammonium group, (2) the side chain ammonium group, and (3) the peptide backbone. Addition of the aminomethyl group to Phe substantially improved the selectivity for peptide versus amino acid and for an N-terminal vs nonterminal position. Importantly, Q7 binds to N-terminal AMPhe several orders of magnitude more tightly than any of the canonical amino acid residues. The high affinity, single-site selectivity, and small modification in this system make it attractive for the development of minimal affinity tags

Impact of a Positive Viral Polymerase Chain Reaction on Outcomes of Chronic Obstructive Pulmonary Disease (COPD) Exacerbations

INTRODUCTION: More than 15 million adults in the USA have chronic obstructive pulmonary disease. Chronic obstructive pulmonary disease (COPD) places a high burden on the healthcare system. Many hospital admissions are due to an exacerbation, which is suspected to be from a viral cause. The purpose of this analysis was to compare the outcomes of patients with a positive and negative respiratory virus panel who were admitted to the hospital with COPD exacerbations. METHODS: This retrospective cohort study was conducted in the Geisinger Healthcare System. The dataset included 2729 patient encounters between 1 January 2006 and 30 November 2017. Hospital length of stay was calculated as the discrete number of calendar days a patient was in the hospital. Patient encounters with a positive and negative respiratory virus panel were compared using Pearson\u27s chi-square or Fisher\u27s exact test for categorical variables and Student\u27s t-test or Wilcoxon rank-sum tests for continuous variables. RESULTS: There were 1626 patients with a total of 2729 chronic obstructive pulmonary disease exacerbation encounters. Nineteen percent of those encounters (n = 524) had a respiratory virus panel performed during their admission. Among these encounters, 161 (30.7%) had positive results, and 363 (69.3%) had negative results. For encounters with the respiratory virus panel, the mean age was 64.5, 59.5% were female, 98.9% were white, and the mean body mass index was 26.6. Those with a negative respiratory virus panel had a higher median white blood cell count (11.1 vs. 9.9, p = 0.0076). There were no other statistically significant differences in characteristics between the two groups. Respiratory virus panel positive patients had a statistically significant longer hospital length of stay. There were no significant differences with respect to being on mechanical ventilation or ventilation-free days. CONCLUSION: This study shows that a positive respiratory virus panel is associated with increased length of hospital stay. Early diagnosis of chronic obstructive pulmonary disease exacerbation patients with positive viral panel would help identify patients with a longer length of stay

Does CD4+CD25+foxp3+ cell (Treg) and IL-10 profile determine susceptibility to immune reconstitution inflammatory syndrome (IRIS) in HIV disease?

HIV-specific T-lymphocyte responses that underlie IRIS are incomplete and largely remain hypothetical. Of the several mechanisms presented by the host to control host immunological damage, Treg cells are believed to play a critical role. Using the available experimental evidence, it is proposed that enormous synthesis of conventional FoxP3- Th cells (responsive) often renders subjects inherently vulnerable to IRIS, whereas that of natural FoxP3+ Treg cell synthesis predominate among subjects that may not progress to IRIS. We also propose that IRIS non-developers generate precursor T-cells with a high avidity to generate CD4+CD25+FoxP3+ Tregs whereas IRIS developers generate T-cells of intermediate avidity yielding Th0 cells and effector T-cells to mediate the generation of proinflammatory cytokines in response to cell-signaling factors (IL-2, IL-6 etc.). Researchers have shown that IL-10 Tregs (along with TGF-β, a known anti-inflammatory cytokine) limit immune responses against microbial antigens in addition to effectively controlling HIV replication, the prime objective of HAART. Although certain technical limitations are described herein, we advocate measures to test the role of Tregs in IRIS

A comparative study on chitosan nanoparticle synthesis methodologies for application in aquaculture through toxicity studies

Abstract Chitosan nanoparticles (CSNPs) have been recently used for various applications in aquaculture, especially as drug carriers. The aim of this study was to synthesise and investigate a superlative method of CSNP synthesis for application in aquaculture through aquaculture‐based toxicology screening methods. Two different methods were analysed: the first a direct ionic gelation method (A) and the other involving a low‐molecular‐weight chitosan microparticle intermediate method (B). Dynamic light scattering characterisation revealed that the CSNP particle sizes were 192.7 ± 11.8 and 22.9 nm from methods A and B, respectively. The LC50 values for brine shrimp toxicity were found to be 1.51 and 0.02 ppt in 24 h for methods A and B, respectively. Acute toxicity studies in Litopenaeus vannamei rendered LC50 values of 3235.94 and 2884.03 ppt in 24 h for methods A and B, respectively. Zebrafish toxicity studies revealed mortality rates of 21.67% and 55% at 20 mg/L concentration for methods A and B, respectively, with an increased expression of intracellular reactive oxygen species in method B. From these findings, it can be concluded that a comparatively reduced toxicity of CSNPs derived from ionic gelation method makes it more appropriate for application in aquaculture