INTERMOLECULAR H-BONDS IN ACETONITRILE AND ITS SOLUTIONS. RAMAN SPECTRA AND AB INITIO CALCULATIONS

Author Institution: Samarkand State University, 15, University blvd., Samarkand, 703004, Uzbekistan\noindent The band of CN vibrations in pure acetonitrile in Raman spectra is located at 2254 cm$^{-1}$, and it is asymmetric in low-frequency region. In mixture with acetic acid we observed appearance of a band of aggregations of acetonitrile molecules with those of acetic acid in high-frequency region. Relative intensity of the band increases with decreasing concentration of acetonitrile. \noindent Calculations showed that in monomer molecule of acid one of H atoms of CH$_3$ group participates in formation of weak intramolecular H-bond with = O atom. Length of this bond is 2,55 A. For monomer molecule interaction of = O atom with H atom of O - H group also takes place. Optimized model of dimer "acetonitrile - acetic acid" represents closed aggregation with H-bond between N atom and H atom of O-H group. Moreover, there is a possibility of formation of intramolecular H - bond between = O atom of acid and one of H atoms of CH$_3$ group of acetonitrile. The length of H-bond N...H-O is 2,21 A, and for H$_2$C - H ... O is 2,61 A. Energy profit in this case is 5,3 kcal/mole. Weak intramolecular H-bond between O atom of C = O group and one of H atoms of CH$_3$ group of acid is preserved also in dimer "acetonitrile - acetic acid"

INTERMOLECULAR INTERACTION IN LIQUID CHLOROFORM AND ITS SOLUTIONS. NON-EMPIRICAL CALCULATIONS AND RAMAN SPECTRA

Author Institution: Samarkand State University. 703004 Samarkand, University blvd 15, Uzbekistan; Samarkand State University. 703004 Samarkand, University blvd 15, Uzbekistan; Samarkand State University. 703004 Samarkand, University blvd 15, Uzbekistan; Samarkand State University. 703004 Samarkand, University blvd 15, UzbekistanIt was studied Raman spectra of C-H and C-D vibrations of chloroform and its solution with acetonitrile. It was found that in pure chloroform the band maxima frequency noncoincidance in parallel and perpendicular polarized components of Raman spectra line. Difference is 1.8 cm-1 for chloroform and 1.5 cm-1 for deuteried chloroform. At dilution in neutral solvent this frequence difference is decreased. The results was explained by molecular aggregation in pure liquid, when for monomers and aggregates correspond two near placed and overlapping bands with different values of depolarization ratio. The calculations on base of DFT method (B3LYP) show that the such aggregations formation in liquid is possible, at this in dimmer the hydrogen atom of C-H band of one molecule is oriented to one of three atoms chlorine of other molecule of chloroform. The frequency difference of monomer and dimer vibrations is 2 cm-1. In mixture with acetonitrile the bands C-H and C-D are experienced high frequency shift in comparison with place of band in pare liquid, at this the band with concentration change go through maximum that indicates about band complexity in mixtur

Patients with Crohn's disease have longer post-operative in-hospital stay than patients with colon cancer but no difference in complications' rate

BACKGROUNDRight hemicolectomy or ileocecal resection are used to treat benign conditions like Crohn's disease (CD) and malignant ones like colon cancer (CC).AIMTo investigate differences in pre- and peri-operative factors and their impact on post-operative outcome in patients with CC and CD.METHODSThis is a sub-group analysis of the European Society of Coloproctology's prospective, multi-centre snapshot audit. Adult patients with CC and CD undergoing right hemicolectomy or ileocecal resection were included. Primary outcome measure was 30-d post-operative complications. Secondary outcome measures were post-operative length of stay (LOS) at and readmission.RESULTSThree hundred and seventy-five patients with CD and 2,515 patients with CC were included. Patients with CD were younger (median = 37 years for CD and 71 years for CC (P < 0.01), had lower American Society of Anesthesiology score (ASA) grade (P < 0.01) and less comorbidity (P < 0.01), but were more likely to be current smokers (P < 0.01). Patients with CD were more frequently operated on by colorectal surgeons (P < 0.01) and frequently underwent ileocecal resection (P < 0.01) with higher rate of de-functioning/primary stoma construction (P < 0.01). Thirty-day post-operative mortality occurred exclusively in the CC group (66/2515, 2.3%). In multivariate analyses, the risk of post-operative complications was similar in the two groups (OR 0.80, 95%CI: 0.54-1.17; P = 0.25). Patients with CD had a significantly longer LOS (Geometric mean 0.87, 95%CI: 0.79-0.95; P < 0.01). There was no difference in re-admission rates. The audit did not collect data on post-operative enhanced recovery protocols that are implemented in the different participating centers.CONCLUSIONPatients with CD were younger, with lower ASA grade, less comorbidity, operated on by experienced surgeons and underwent less radical resection but had a longer LOS than patients with CC although complication's rate was not different between the two groups

The impact of stapling technique and surgeon specialism on anastomotic failure after right?sided colorectal resection: an international multicentre, prospective audit

Aim There is little evidence to support choice of technique and configuration for stapled anastomoses after right hemicolectomy and ileocaecal resection. This study aimed to determine the relationship between stapling technique and anastomotic failure. Method Any unit performing gastrointestinal surgery was invited to contribute data on consecutive adult patients undergoing right hemicolectomy or ileocolic resection to this prospective, observational, international, multicentre study. Patients undergoing stapled, side?to?side ileocolic anastomoses were identified and multilevel, multivariable logistic regression analyses were performed to explore factors associated with anastomotic leak. Results One thousand three hundred and forty?seven patients were included from 200 centres in 32 countries. The overall anastomotic leak rate was 8.3%. Upon multivariate analysis there was no difference in leak rate with use of a cutting stapler for apical closure compared with a noncutting stapler (8.4% vs 8.0%, OR 0.91, 95% CI 0.54–1.53, P = 0.72). Oversewing of the apical staple line, whether in the cutting group (7.9% vs 9.7%, OR 0.87, 95% CI 0.52–1.46, P = 0.60) or noncutting group (8.9% vs 5.7%, OR 1.40, 95% CI 0.46–4.23, P = 0.55) also conferred no benefit in terms of reducing leak rates. Surgeons reporting to be general surgeons had a significantly higher leak rate than those reporting to be colorectal surgeons (12.1% vs 7.3%, OR 1.65, 95% CI 1.04–2.64, P = 0.04). Conclusion This study did not identify any difference in anastomotic leak rates according to the type of stapling device used to close the apical aspect. In addition, oversewing of the anastomotic staple lines appears to confer no benefit in terms of reducing leak rates. Although general surgeons operated on patients with more high?risk characteristics than colorectal surgeons, a higher leak rate for general surgeons which remained after risk adjustment needs further exploration