Quantum chemical study of gas-phase reactions of isoprene with OH radicals producing highly oxidised second-generation products.

The formation of secondary organic aerosols caused by atmospheric oxidation of isoprene is harmful to human health and the climate; thus, isoprene oxidation is further mandatory to obtain less harmful or harmless highly oxidised products. In this numerical investigation, 2-hydroperoxy-2-methylbut-3-en-1-ol (ISOPOOH) was considered the model compound to investigate the formation of three RO2 radicals (C5H11O4, C5H11O6 and C5H11O5) and two saturated highly oxidised products (C5H12O6 and C5H10O6). The complete reaction network and its thermodynamics and kinetics were analysed to obtain the most probable and feasible reaction pathways. Four different levels of theories (HF, B3LYP, M06-2X and ωB97XD with basis set of 6-31+g(d,p)) were employed to explore a global minimum of ISOPOOH. All theories provided approximately close energetics; however, because of the novelty of the functional and parameterisation of the basis set, the ωB97XD functional was selected to examine the reaction mechanism. C5H12O6 was formed as the second-generation highly oxidised product during ISOPOOH oxidation.

First-principles study on the gas-phase decomposition of bio-oil oxygenated compounds over the palladium catalyst surface.

Unprocessed bio-oils derived from the thermochemical conversion of lignocellulosic biomass suffer from low energy density primarily due to the presence of high amounts of oxygen functional groups. Therefore, the elimination of oxygen atoms over a suitable catalyst surface is viewed as one of the appropriate mechanisms for elevating the quality of bio-oils. Here, in this computational study, three oxygenated bio-oil model compounds, namely, 2-butenal, butan-2,3-diol, and butan-2,3-dione were considered as the representative compounds of the oxygenated catalogue of bio-oils. The decomposition mechanisms of these model compounds along with microkinetic modelling were studied over a palladium catalyst surface to produce low or no oxygen-containing products under the density functional theory (DFT) framework. Propene and methane were observed as the major products in the decomposition processes of 2-butenal and butan-2,3-dione, respectively. Butan-2,3-diol showed no major products due to high barriers. The increase in temperature was observed to be beneficial for improving the reaction rate constants; however, in many cases, the elevation of temperature shifted the equilibrium towards the reactants. CO acted as one of the major inhibitors due to the decarbonylation reaction of aldehydes.

Role of Chromohysteroscopy in Evaluation of Endometrial Pathology Using Methylene Blue Dye.

BACKGROUND: Chromohysteroscopy is expected to help in diagnosing subtle endometrial pathologies which could be missed on conventional hysteroscopy and also help in targeting biopsy from endometrium. OBJECTIVE: To study staining pattern of endometrium in patients undergoing chromohysteroscopy and to evaluate and compare the histopathology of chromohysteroscopy-guided endometrial biopsy with conventional endometrial sampling. METHOD: This was a cross-sectional study conducted during the period of 18 months in Department of Obstetrics and Gynaecology, ESI PGIMSR, New Delhi, India, from September 2016 to February 2018. Totally, 60 women with complaints of infertility, failed intrauterine insemination (IUI), recurrent spontaneous abortions (RSA), heavy menstrual bleeding (HMB), intermenstrual bleeding (IMB) and postmenopausal bleeding (PMB) meeting inclusion criteria were evaluated and enrolled in the study. In patients with normal looking endometrium on hysteroscopy, methylene blue dye was administered through the hysteroscopic inlet. Tissue samples were obtained from stained areas followed by blind endometrial sampling immediately. The results of chromohysteroscopy-guided biopsy from light- and dark-blue-stained areas and blind biopsy were compared. RESULTS: Mean age of the study group was 37 years, with mean BMI of 24 kg/m2. There were 24 cases of HMB, 9 of IMB, 7 of PMB, 15 of infertility, 2 of failed IUI and 3 with RSA. On chromohysteroscopy, 39(65%) cases showed light-stained endometrium (group I) and 21(35%) showed dark-stained endometrium (group II). Comparison was done between histopathology obtained through chromohysteroscopy and blind endometrial sampling. The diagnostic accuracy of chromohysteroscopy-guided endometrial biopsy in evaluation of endometrial pathology was 86.67% with sensitivity of 91.67%, specificity of 85.41%, PPV of 61.12% and NPV of 97.61% (P <0.001). CONCLUSION: Chromohysteroscopy was able to detect endometrial pathology which was missed on conventional hysteroscopy and detected more cases of endometrial pathology than blind endometrial sampling.

Molecular modeling approach to elucidate gas phase hydrodeoxygenation of guaiacol over a Pd(111) catalyst within DFT framework.

Excessive amounts of oxy-functional groups in unprocessed bio-oil vitiate its quality as fuel; therefore, it has to be channelized to upgrading processes, and catalytic hydrodeoxygenation is one of the most suitable routes for the upgrading of crude bio-oil. In this computational work, catalytic hydrodeoxygenation (HDO) of guaiacol, which is an important phenolic compound of crude bio-oil, has been carried out using density functional theory (DFT) over a Pd(111) catalyst. The Pd(111) catalyst surface does not endorse direct eliminations of functional groups of guaiacol; however, it is found to perform excellently in stepwise dehydrogenation reactions of oxy-functionals of guaiacol according to present DFT results. The catechol product, formed through dehydrogenation of the methoxy group, followed by elimination of CH2 and association of the hydrogen atom, has been identified as one of the major products. The overall reaction rate is controlled by scission of CH2 from 2-methylene-oxy-phenol with an activation energy demand of 23.06 kcal mol-1. Further, the kinetic analysis of each reaction step involved in HDO of guaiacol over the Pd(111) catalyst surface has also been carried out at atmospheric pressure and at a wide range of temperatures from 473 to 673 K, with temperature intervals of 50 K. In the kinetic analysis part, various kinetic parameters, such as forward and reverse reaction rate constants, Arrhenius constants, and equilibrium rate constants, are reported. The kinetic modeling of the dominating reaction steps has revealed that even a lower temperature of 473 K provides a favorable reaction environment; and the temperature increment further improves the reaction favorability.

Quantum chemical study on gas phase pyrolysis of p-isopropenylphenol.

In the pyrolysis of Sphagnum moss species, p-isopropenylphenol (p-IPP) is a major product which has been considered in this density functional theory based computational study for its conversion to various products such as benzene, phenol, 4-propenylphenol, indan-5-ol, 4-propylcyclohexanone, 4-cyclopropylphenol, etc. In order to achieve these products, eight different reaction schemes are performed using B3LYP/6-311 + g (d,p) level of theory. Further, thermodynamic properties such as reaction free energies and reaction enthalpies associated with these eight reaction schemes are developed in the temperature range of 298-898 K. The reaction schemes that include partial hydrogenation of the aromatic carbon followed by elimination of functional groups are found to demand low activation energy. The production of benzene from p-IPP with isopropenylbenzene as an intermediate product requiring only 19.83 kcal/mol of activation energy is the rate limiting reaction step. Indan-5-ol produced from p-IPP is validated with the literature results and found excellent agreement between two results. Furthermore, the temperature is found to have phenomenal effect in each reaction scheme.

Asbestos-induced lung disease in small-scale clutch manufacturing workers.

BACKGROUND: The crocidolite variety of asbestos is banned. However, chrysotile, which is not prohibited, is still used in developing countries in making products such as clutch plate. Fourteen workers from a small-scale clutch plate-manufacturing factory were analyzed for asbestos-induced lung disease as one of their colleagues had expired due to asbestosis. AIMS: This study was conducted to evaluate the awareness of workers, the prevalence and type of asbestos-induced lung disease, and the sensitivity and specificity of diffusion test. MATERIALS AND METHODS: History, examination, chest radiograph, spirometry with diffusion, and high resolution computed tomography (HRCT) thorax was performed in all the workers. The diagnosis of asbestos-induced lung disease was suspected on the basis of HRCT. This was subsequently confirmed on transbronchial lung biopsy (TBLB). RESULTS: None of the workers had detailed information about asbestos and its ill effects. Eleven out of 14 (71.42%) workers had asbestos-induced lung disease. All 11 had small airway disease (SAD). Three had SAD alone, 6 had additional interstitial lung disease (ILD), and 2 patients had additional ILD and chronic obstructive pulmonary disease. Sensitivity and specificity of residual volume (RV) or total lung capacity (TLC) for detecting SAD was 90% and 100%, respectively, and that of diffusion capacity of lung for carbon monoxide (DLCO) for detecting ILD was 100%. CONCLUSION: The awareness about asbestos in small-scale clutch-plate manufacturing industry is poor. The usage of chrysotile should be strictly regulated as morbidity and mortality is high. DLCO and RV/TLC are sensitive and specific in detecting nonmalignant asbestos induced lung disease.

Thyroid cytopathology reporting by the bethesda system: a two-year prospective study in an academic institution.

Background. The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) has attempted to standardize reporting and cytological criteria in aspiration smears. Aims. The objective of this study was to analyze the thyroid cytology smears by TBSRTC, to determine the distribution of diagnostic categories and subcategories, to analyze cytological features, and to correlate the cytopathology with histopathology, wherever surgery was done. Materials and Methods. This was a prospective study of 225 fine needle aspirations (FNA) of thyroid nodules. All fine needle aspiration cytology (FNAC) diagnoses were classified according to the features given in the monograph of TBSRTC into nondiagnostic/unsatisfactory (ND/UNS), benign, atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS), follicular neoplasm/suspicious of a follicular neoplasm (FN/SFN), suspicious for malignancy (SFM), and malignant. Cytohistological correlation was done, when surgical material was available. Results. The distribution of various categories from 225 evaluated thyroid nodules was as follows: 7.2% ND/UNS, 80.0% benign, 4.9% AUS/FLUS, 2.2% FN, 3.5% SFM, and 2.2% malignant. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated. Conclusions. TBSRTC is an excellent reporting system for thyroid FNA. It also provides clear management guidelines to clinicians to go for follow-up FNA or surgery and also the extent of surgery.

A comparison of effect of preemptive use of oral gabapentin and pregabalin for acute post-operative pain after surgery under spinal anesthesia.

BACKGROUND AND AIMS: Preemptive analgesia is an antinociceptive treatment that prevents establishment of altered processing of afferent input. Pregabalin has been claimed to be more effective in preventing neuropathic component of acute nociceptive pain of surgery. We conducted a study to compare the effect of oral gabapentin and pregabalin with control group for post-operative analgesia. MATERIALS AND METHODS: A total of 90 ASA grade I and II patients posted for elective gynecological surgeries were randomized into 3 groups (group A, B and C of 30 patients each). One hour before entering into the operation theatre the blinded drug selected for the study was given with a sip of water. Group A- received identical placebo capsule, Group B- received 600mg of gabapentin capsule and Group C - received 150 mg of pregabalin capsule. Spinal anesthesia was performed at L3-L4 interspace and a volume of 3.5 ml of 0.5% bupivacaine heavy injected over 30sec through a 25 G spinal needle. VAS score at first rescue analgesia, mean time of onset of analgesia, level of sensory block at 5min and 10 min interval, onset of motor block, total duration of analgesia and total requirement of rescue analgesia were observed as primary outcome. Hemodynamics and side effects were recorded as secondary outcome in all patients. RESULTS: A significantly longer mean duration of effective analgesia in group C was observed compared with other groups (P < 0.001). The mean duration of effective analgesia in group C was 535.16 ± 32.86 min versus 151.83 ± 16.21 minutes in group A and 302.00 ± 24.26 minutes in group B. The mean numbers of doses of rescue analgesia in the first 24 hours in group A, B and C was 4.7 ± 0.65, 4.1 ±0.66 and 3.9±0.614. (P value <0.001). CONCLUSION: We conclude that preemptive use of gabapentin 600mg and pregabalin 150 mg orally significantly reduces the postoperative rescue analgesic requirement and increases the duration of postoperative analgesia in patients undergoing elective gynecological surgeries under spinal anesthesia.

A pilot study evaluating genetic alterations that drive tobacco- and betel quid-associated oral cancer in Northeast India.

The susceptibility of an individual to oral cancer is mediated by genetic factors and carcinogen-exposure behaviors such as betel quid chewing, tobacco use, and alcohol consumption. This pilot study was aimed to identify the genetic alteration in 100 bp upstream and downstream flanking regions in addition to the exonic regions of 169 cancer-associated genes by using Next Generation sequencing with aim to elucidate the molecular pathogenesis of tobacco- and betel quid-associated oral cancer of Northeast India. To understand the role of chemical compounds present in tobacco and betel quid associated with the progression of oral cancer, single nucleotide polymorphisms (SNPs) and insertion and deletion (Indels) found in this study were analyzed for their association with chemical compounds found in tobacco and betel quid using Comparative Toxogenomic Database. Genes (AR, BRCA1, IL8, and TP53) with novel SNP were found to be associated with arecoline which is the major component of areca nut. Genes (BARD1, BRCA2, CCND2, IGF1R, MSH6, and RASSF1) with novel deletion and genes (APC, BRMS1, CDK2AP1, CDKN2B, GAS1, IGF1R, and RB1) with novel insertion were found to be associated with aflatoxin B1 which is produced by fermented areca nut. Genes (ADH6, APC, AR, BARD1, BRMS1, CDKN1A, E2F1, FGFR4, FLNC, HRAS, IGF1R, IL12B, IL8, NBL1, STAT5B, and TP53) with novel SNP were found to be associated with aflatoxin B1. Genes (ATM, BRCA1, CDKN1A, EGFR, IL8, and TP53) with novel SNP were found to be associated with tobacco specific nitrosamines.

A prospective study of soft tissue tumors histocytopathology correlation.

Background. Soft tissue tumors are defined as nonepithelial extraskeletal tissue of the body exclusive of the reticuloendothelial system, glia, and supporting tissue of various parenchymal organs. The absence of recognizable tissue architectural patterns in cytological preparation makes diagnosis by FNAC more difficult. Aims. To assess the utility of FNAC in diagnosing soft tissue tumors and to determine their patterns compared with with the respective histopathology results. Materials and Methods. 150 cases of soft tissue tumors were included in this study for cytologic and histologic correlation. FNAC air dried smears were stained with Giemsa stain and 95% ethanol fixed smears were stained with Papanicolaou stain. The smears were studied for cytological diagnosis and were categorized as benign, suspicious of malignancy, and malignant along with specific subtyping of the lesion. All diagnostic FNAC results were compared for diagnostic concordance using histology results as the "gold standard." Results. The sensitivity, specificity, positive predictive value, negative predictive value, and efficiency were 70%, 100%, 97.90%, 100%, and 98%, respectively. P value was <0.0001 which shows statistically extreme significant correlation. Conclusion. FNAC is a very important preliminary diagnostic tool in palpable soft tissue lumps with high degree of correlation with the final histopathology report.