318 research outputs found

    Volumetric study of the olfactory bulb in patients with chronic rhinonasal sinusitis using MRI

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    AbstractObjectiveOlfaction plays an important role in human daily life. The olfactory bulb size is dependent on stimulation. Smell loss is one of the main symptoms in chronic rhinonasal sinusitis. MRI has been indicated to evaluate the size of the olfactory bulb in such patients.The aim of this study was to assess the volumetric changes of the olfactory bulb in patients with sinonasal polyposis before and after treatment using MRI.Patients and methodsFifteen control subjects and 30 patients were included in the study, 24 of them patients underwent endoscopic sinus surgery. Volumetric analysis of their olfactory bulb volume was done using MRI and specialized software.ResultsIt was found that the olfactory bulb volume was significantly smaller in patients (19.98±5.88mm3) when compared to control mean (39.6±13.8mm3) and there was a significant increase in the olfactory bulb volumes in patients who underwent surgery 6months postoperatively (24.79±5.11mm3).ConclusionsMRI with volumetric analysis is a useful tool in assessment of the olfactory bulb volume in patients with olfactory loss and appears to be of help in assessment of the degree of recovery in patients after sinus surgery

    On Hermite-Hermite matrix polynomials

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    summary:In this paper the definition of Hermite-Hermite matrix polynomials is introduced starting from the Hermite matrix polynomials. An explicit representation, a matrix recurrence relation for the Hermite-Hermite matrix polynomials are given and differential equations satisfied by them is presented. A new expansion of the matrix exponential for a wide class of matrices in terms of Hermite-Hermite matrix polynomials is proposed

    The role of magnetic resonance imaging and magnetic resonance sialography in the evaluation of salivary sialolithiasis : radiologic-endoscopic correlation

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    Purpose: To evaluate the role of magnetic resonance imaging (MRI) and MR sialography in salivary gland calculi in correlation with sialendoscopy. Material and methods: In this prospective study, pre-therapeutic MRI was performed for patients with clinically suspected sialolithiasis. In addition, sialendoscopy with or without surgery was performed. The detectability, number, size, and location of calculi (distance of obstruction from the ostium and masseter line) and the condition of the main duct at MRI were reported. Agreement between the 2 readers was confirmed for all MRI findings. Data regarding the detectability, number, and size of calculi were correlated with endoscopy. Results: There was excellent agreement between the 2 readers regarding the detection and number of calculi at MR sialography (κ = 1, p < 0.001). As regards MRI measurements, excellent interclass correlation was found between the 2 readers regarding size of calculi, distance of calculi from the ostium, and distance from the masseter line (κ = 0.98, 0.98, 0.97, respectively; p < 0.001). In correlation with sialendoscopy, MRI was false negative in 1 patient, and it missed 1 calculus in 3 patients with multiple calculi. There was no statistically significant difference between the size of calculi detected by MRI and true size of calculi retrieved by sialendoscopy. Conclusion: MR sialography is an accurate modality for diagnosis of the presence, size, and location of sialolithiasis and offers accurate ductal mapping for sialendoscopists

    Preparation of Some Eco-friendly Corrosion Inhibitors Having Antibacterial Activity from Sea Food Waste

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    Chitosan is one of the important biopolymers and it is extracted from exoskeletons of crustaceans in sea food waste. It is a suitable eco-friendly carbon steel corrosion inhibitor in acid media; the deacetylation degree of prepared chitosan is more than 85.16 %, and the molecular weight average is 109 kDa. Chitosan was modified to 2-N,N-diethylbenzene ammonium chloride N-oxoethyl chitosan (compound I), and 12-ammonium chloride N-oxododecan chitosan (compound II) as soluble water derivatives. The corrosion inhibition efficiency for carbon steel of compound (I) in 1 M HCl at varying temperature is higher than for chitosan and compound (II). However, the antibacterial activity of chitosan for Enterococcus faecalis, Escherichia coli, Staphylococcus aureus, and Candida albicans is higher than for its derivatives, and the minimum inhibition concentration and minimum bacterial concentration of chitosan and its derivatives were carried out with the same strain

    REMOVAL OF FERRIC IONS (Fe+3) FROM NEUTRAL SOLUTIONS USING MODIFIED CHITOSAN

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    The object of this study is to assess the removal of Fe(III) ions from aqueous solutions onto modified chitosan. The effect of various parameters has been investigated by the following batch adsorption technique. The various variables studied include initial concentration of the adsorbate, agitation time, adsorbent dosage, kinetics, influence of temperature. The experimental data was fit well to the Freundlich isotherm. Thermodynamic parameters such as ΔH, ΔS and ΔG were calculated, indicating that the adsorption was spontaneous and endothermic nature

    The COVID-19 Pandemic: A Comprehensive Review of Taxonomy, Genetics, Epidemiology, Diagnosis, Treatment, and Control

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    A pneumonia outbreak with unknown etiology was reported in Wuhan, Hubei province, China, in December 2019, associated with the Huanan Seafood Wholesale Market. The causative agent of the outbreak was identified by the WHO as the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), producing the disease named coronavirus disease-2019 (COVID-19). The virus is closely related (96.3%) to bat coronavirus RaTG13, based on phylogenetic analysis. Human-to-human transmission has been confirmed even from asymptomatic carriers. The virus has spread to at least 200 countries, and more than 1,700,000 confirmed cases and 111,600 deaths have been recorded, with massive global increases in the number of cases daily. Therefore, the WHO has declared COVID-19 a pandemic. The disease is characterized by fever, dry cough, and chest pain with pneumonia in severe cases. In the beginning, the world public health authorities tried to eradicate the disease in China through quarantine but are now transitioning to prevention strategies worldwide to delay its spread. To date, there are no available vaccines or specific therapeutic drugs to treat the virus. There are many knowledge gaps about the newly emerged SARS-CoV-2, leading to misinformation. Therefore, in this review, we provide recent information about the COVID-19 pandemic. This review also provides insights for the control of pathogenic infections in humans such as SARS-CoV-2 infection and future spillovers

    Structural and dynamic determinants for highly selective RET kinase inhibition reveal cryptic druggability.

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    The structural and dynamic determinants for highly selective RET kinase inhibition are poorly understood. Here we demonstrate by applying an integrated structural, computational and biochemical approach that the druggability landscape of the RET active site is determined by the conformational setting of the ATP-binding (P-) loop and its coordination with the αC helix. Open and intermediate P-loop structures display additional druggable vulnerabilities within the active site that were not exploited by first generation RET inhibitors. We identify a cryptic pocket adjacent to the catalytic lysine formed by K758, L760, E768 and L772, that we name the post-lysine pocket, with higher druggability potential than the adenine-binding site and with important implications in the regulation of phospho-tyrosine kinase activity. Crystal structure and simulation data show that the binding mode of highly-selective RET kinase inhibitors LOXO-292 and BLU-667 is controlled by a synchronous open P-loop and αC-in configuration that allows accessibility to the post-lysine pocket. Molecular dynamics simulation show that these inhibitors efficiently occupy the post-lysine pocket with high stability through the simulation time-scale (300 ns), with both inhibitors forming hydrophobic contacts in the pocket further stabilized by pi-cation interactions with the catalytic K758. Engineered mutants targeting the post-lysine pocket impact on inhibitor binding and sensitivity, as well as RET tyrosine kinase activity. The identification of the post-lysine pocket as a cryptic druggable vulnerability in the RET kinase and its exploitation by second generation RET inhibitors has important implications for future drug design and the development of personalized therapies for patients with RET-driven cancers.We thank the Centro Nacional de Investigaciones Oncológicas (CNIO), which is supported by the Instituto de Salud Carlos III and recognized as a “Severo Ochoa” Centre of Excellence (ref. CEX2019-000891-S, awarded by MCIN/AEI/ 10.13039/501100011033) for core funding and supporting this study. This work was further supported by projects: BFU2017-86710-R funded by MCIN/ AEI /10.13039/501100011033 and ERDF “A way of making Europe”, PID2020-117580RB-I00 funded by MCIN/ AEI /10.13039/501100011033, RYC-2016-1938 funded by MCIN/AEI /10.13039/501100011033 and ESF “Investing in your future”, and a Marie Curie WHRI-ACADEMY International grant (number 608765) to IP-M and a CNIO-Friends predoctoral Carmen Gloria Bonnet Fellowship to MAS.N

    Flexural Response of RC beams cast with normal and steel fibre concrete internally reinforced with various types of FRP bars

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    Šipke od vlaknima armiranih polimera (FRP) mogu se koristiti kao zamjena za čelične šipke da bi se izbjegla korozija čelika. U ovom radu su pripremljeni i ispitani uzorci armiranobetonskih greda od običnog betona i betona s čeličnim vlaknima (SFC) armirani šipkama od staklenih vlakana, armiranih polimera (GFRP) ili čeličnim šipkama. Rezultati ispitivanja pokazali su da se tlačna čvrstoća betona povećala s povećanjem omjera čeličnih vlakana (SF) koji su korišteni u ovom istraživanju (od 0 % do 1,5 %). Jednako tako, grede armirane GFRP šipkama imale su nižu početnu krutost i veću duktilnost nego one armirane čeličnim šipkama.Fibre Reinforced Polymer (FRP) bars can be used as an alternate for reinforcing bars to avoid corrosion of steel. Samples of reinforced concrete beams cast with normal or steel fibre concrete (SFC), internally reinforced with Glass Fibre Reinforced Polymer (GFRP) or steel bars, are prepared and tested in this paper. Experimental results show that compressive strength of concrete increases with an increase in steel fibre (SF) ratio used in this study (from 0% to 1.5%). Also, the beams reinforced with GFRP bars have a lower initial stiffness and higher ductility than those reinforced with steel bars

    Pregnenolone sulfate analogues differentially modulate GABAA receptor closed/desensitised states

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    BACKGROUND AND PURPOSE: GABAA receptors are regulated by numerous classes of allosteric modulators. However, regulation of receptor macroscopic desensitisation remains largely unexplored and may offer new therapeutic opportunities. Here, we report the emerging potential for modulating desensitisation with analogues of the endogenous inhibitory neurosteroid, pregnenolone sulfate. EXPERIMENTAL APPROACH: New pregnenolone sulfate analogues were synthesised incorporating various heterocyclic substitutions located at the C-21 position on ring D. The pharmacological profiles of these compounds were assessed using electrophysiology and recombinant GABAA receptors together with mutagenesis, molecular dynamics simulations, structural modelling and kinetic simulations. KEY RESULTS: All seven analogues retained a negative allosteric modulatory capability whilst exhibiting diverse potencies. Interestingly, we observed differential effects on GABA current decay by compounds incorporating either a six- (compound 5) or five-membered heterocyclic ring (compound 6) on C-21, which was independent of their potencies as inhibitors. We propose that differences in molecular charges, and the targeted binding of analogues to specific states of the GABAA receptor, are the most likely cause of the distinctive functional profiles. CONCLUSIONS AND IMPLICATIONS: Our findings reveal that heterocyclic addition to inhibitory neurosteroids not only affected their potency and macroscopic efficacy but also affected innate receptor mechanisms that underlie desensitisation. Acute modulation of macroscopic desensitisation will determine the degree and duration of GABA inhibition, which are vital for the integration of neural circuit activity. Discovery of this form of modulation could present an opportunity for next-generation GABAA receptor drug design and development

    Thermodynamic Investigation and Mixed Ligand Complex Formation of 1,4-Bis-(3-aminopropyl)-piperazine and Biorelevant Ligands

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    Thermodynamic parameters for protonation of 1,4-bis(3-aminopropyl)-piperazine (BAPP) and its metal complexation with some divalent metal ions were determined in aqueous solution at constant ionic strength (0.1 M NaNO3) using a potentiometric technique. The order of –ΔG0 and –ΔH0 was found to obey , in accordance with the Irving-Williams order. The formation equilibria of zinc (II) complexes and the ternary complexes Zn(BAPP)L, where L = amino acid, amides, or DNA constituents), have been investigated. Ternary complexes are formed by a simultaneous mechanism. The concentration distribution of the complexes in solution was evaluated as a function of pH. Stoichiometry and stability constants for the complexes formed are reported and discussed. The stability of ternary complexes was quantitatively compared with their corresponding binary complexes in terms of the parameter Δlog K
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