496 research outputs found

    Secretory activity of gastroduodenal zone before and after cholecystectomia

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    Вивчено функціональні особливості секреторної активності гастродуоденальної зони до та піс­ля холецистектомії. Встановлено пригнічення ферментовидільної функції шлунка у хворих із постхолецистектомічним синдромом. З’ясовано, що наявність дуодено-гастрального рефлюксу свідчить про дуоденостаз і недостатність замикальної функції пілоричного сфінктера. У хворих видалення жовчного міхура призводить до аритмії циркадних і ультрадіадних ритмів усієї травної системи й, у тому числі, до порушень активності секреторних залоз шлунка.Изучены функциональные особенности секреторной активности гастродуоденальной зоны до и пис¬ля холецистэктомии. Установлено угнетение ферментовыводящей функции желудка у больных с постхолецистэктомический синдромом. Выяснено, что наличие дуодено- гастральной рефлюкса свидетельствует о дуоденостаз и недостаточность замыкательной функции пилорического сфинктера. У больных удаление желчного пузыря приводит к аритмии циркадных и ультрадиадних ритмов всей пищеварительной системы и, в том числе, к нарушениям активности секреторных желез желудка.Functional features of the gastroduodenal zone secretory activity before and after cholecystectomia were studied. The oppression of the stomach enzymatic secretion in patients with postcholecystectomia syndrome was established. The presence of duodeno-gastral reflux testifies to the duodenostasis and incompetence of closing function of the pyloric sphincter. Cholecystectomia entails the arrhythmia of circadian and ultradian rhythms of the whole digestive apparatus, including the derangements of the stomach secretory glands

    Infrared and Raman spectroscopic characterization of the hydrogen-bonding network in l-serine crystal

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    The IR spectra (4000-400 cm-1) of neat and isotopically substituted (ND/OD <= 10% D and [congruent with]30% D) polycrystalline l-serine ([alpha]-amino-[beta]-hydroxypropionic acid; HO-CH2-CH(NH3)+-COO-) were recorded in the temperature range 300-10 K and assigned. The isotopic-doping/low-temperature methodology, which allows for decoupling of individual proton vibrational modes from the crystal bulk vibrations, was used for estimating the lengths and energies of the different H-bonds present in l-serine crystal. To this end, the frequency shifts observed in both the NH/OH stretching and out-of-plane bending spectral regions (relatively to reference values for these vibrations in non-hydrogen-bonded l-serine molecules) were used, together with previously developed empirical correlations between these spectral parameters and the H-bond properties. In addition, the room-temperature Raman spectrum (4000-150 cm-1) of a single crystal of neat l-serine was also recorded and interpreted. A systematic comparison was made between the spectroscopic data obtained currently for l-serine and previously for dl-serine, revealing that the vibrational spectra of the two crystals reflect well the different characteristics of their hydrogen-bond networks, and also correlate accurately with the different susceptibility of the two crystals to pressure-induced strain.http://www.sciencedirect.com/science/article/B6THW-4K4WMR3-2/1/211ac428c09ebc9eb45cf3b81d93fcb

    Conformational changes in matrix-isolated 6-methoxyindole: Effects of the thermal and infrared light excitations

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    Conformational changes induced thermally or upon infrared excitation of matrix-isolated 6-methoxyindole were investigated. Narrowband near-infrared excitation of the first overtone of the N–H stretching vibration of each one of the two identified conformers is found to induce a selective large-scale conversion of the pumped conformer into the other one. This easily controllable bidirectional process consists in the intramolecular reorientation of the methoxy group and allowed a full assignment of the infrared spectra of the two conformers. Matrices with different conformational compositions prepared by narrow-band irradiations were subsequently used to investigate the effects of both thermal and broadband infrared excitations on the conformational mixtures. Particular attention is given to the influence of the matrix medium (Ar vs. Xe) and conformational effects of exposition of the sample to the spectrometer light source during the measurements.Peer ReviewedPostprint (author's final draft

    Low-temperature infrared spectra and hydrogen bonding in polycrystalline dl-serine and deuterated derivatives

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    The FT-IR spectra of polycrystalline dl-serine [[alpha]-amino-[beta]-hydroxypropionic acid; HO-CH2-CH(NH3)+-COO-] and isotopically substituted [ND/ODAlcohol (90% D); CD2 (>98% D)] dl-serine were recorded in the range 4000-500 cm-1 in the temperature range 300-10 K, and fully assigned. The isotopic-doping/low-temperature methodology, which allows for decoupling of individual proton vibrational modes from the crystal bulk vibrations, was used to estimate the energies of the different H-bonds present in dl-serine crystal. To this end, the frequency shifts observed in both the NH/OH stretching and out-of-plane bending spectral regions (relatively to reference values for these vibrations in non-hydrogen-bonded dl-serine molecules) were used, together with previously developed empirical correlations. The results are compared with available structural data on this amino acid.http://www.sciencedirect.com/science/article/B6THW-4J91R39-2/1/f8f35f435466c8a5204879d330cbade
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