Опыт применения высокочастотной вентиляции легких во время кардиохирургических операций с искусственным кровообращением

The incidence of various postoperative complications including pulmonary ones is at a high level in a cardiac surgery.The objective: to evaluate the effectiveness of high-frequency lung ventilation during cardiopulmonary bypass as a preventive measure for postoperative pulmonary complications compared to low-volume lung ventilation.Subjects and Methods. 60 patients undergoing cradiac surgery were included in the study. In HF Group (HF ventilation with airway pressure control at the frequency of 300/min, the ratio of duration of inhalation and exhalation is 1:2, mean airway pressure is 8 mbar) and VC Group (lung ventilation during CPB with parameters: tidal volume is 3 ml/kg, respiratory rate is 6/min, and positive end-expiratory pressure is +5 cm H2O).Results. No significant difference in the analysis of the oxygenation index were observed between groups. Frequency of pulmonary atelectasis on chest radiology in postoperative period made 3 (9%) in VC Group and 4 (12%) HF Group (p = 0.71). The frequency of intraoperative recruiting lung maneuvers was 5 (16%) in VС Group and 6 in HF Group (18%) (p = 0,75). The duration of postoperative ventilation did not differ between the groups.Conclusion. HF mechanical ventilation during CPB has no significant advantage over low-volume mechanical ventilation. HF mechanical ventilation and low-volume mechanical ventilation has the same protective effect on the oxygenating function of the lungs after CPB.В кардиохирургии частота развития различных послеоперационных осложнений, в том числе и легочных, остается на достаточно высоком уровне.Цель: оценка эффективности применения высокочастотной искусственной вентиляции легких (ВЧ ИВЛ) во время искусственного кровообращения (ИК) как меры профилактики послеоперационных легочных осложнений в сравнении с малообъемной вентиляцией.Материалы и методы. В исследование включено 60 кардиохирургических пациентов. Группа HF (ВЧ ИВЛ с контролем давления в дыхательных путях с частотой 300/мин, соотношением длительности вдоха и выдоха 1:2, средним давлением в дыхательных путях 8 мбар) и группа VC (вентиляция легких во время ИК с параметрами: дыхательный объем 3 мл/кг, частота дыхания 6/мин, положительное давление конца выдоха +5 см Н2О).Результаты. Статистически значимой разницы между группами в отношении индекса оксигенации на всех этапах ведения пациентов не выявлено. Общее количество пациентов с выявленными ателектазами в послеоперационном периоде в группе VC составило 3 (9%), а в группе HF ‒ 4 (12%) (p = 0,71). Частота применения рекрутмент-маневров после окончания ИК в группе VС – 5 (16%), HF – 6 (18%) (p = 0,75). Продолжительность послеоперационной ИВЛ не различалась между группами исследования.Вывод. Проведение ВЧ ИВЛ в период ИК не имеет существенного преимущества перед малообъемной ИВЛ. Применение обоих режимов вентиляции сопровождается одинаковыми эффектами в отношении послеоперационной оксигенирующей функции легких

RESEARCH OF THE POSSIBILITY OF USING VEGETABLE FILLERS IN THE PRODUCTION OF GRANULATED COTTAGE CHEESE

The article shows the feasibility of using vegetable fillers in the production of granulated cottage cheese. The theoretical and experimental substantiation has been given. The possibility of using vegetable fillers in the production of granulated cottage cheese has been investigated. The objects of the study are: grained cottage cheese; «Half-sour dill pickles» vegetable filler; sample tests of cottage cheese with vegetable filler «Half-sour dill cucumbers»; control sample without the filler. Production of the studied samples was carried out in accordance with the TI TC following the generally accepted technology for the production of grained cottage cheese. Organoleptic and physical and chemical evaluation of experimental samples has been carried out in accordance with the established requirements of the standards.As part of the research, technological compatibility of the «Half-sour dill pickles» vegetable filler and cottage cheese has been studied, the effect of vegetable fillers on the organoleptic and physical and chemical characteristics of the finished product has been shown.The optimal ratio of the main ingredients in the formulation has been experimentally revealed. The optimal formulation has been calculated and the technology for the production of a new product developed. The results of the study indicate that the developed product meets the requirements of regulatory and technical documentation and can be recommended as dietary and sport nutrition due to its physical and chemical, organoleptic and  microbiological indicators

Conical Intersection and Potential Energy Surface Features of a Model Retinal Chromophore: Comparison of EOM-CC and Multireference Methods

This work investigates the performance of equation-of-motion coupled-cluster (EOM-CC) methods for describing the changes in the potential energy surfaces of the penta-2,4-dieniminium cation, a reduced model of the retinal chromophore of visual pigments, due to dynamical electron correlation effects. The ground-state wave function of this model includes charge-transfer and diradical configurations whose weights vary along different displacements and are rapidly changing at the conical intersection between the ground and the first excited states, making the shape of the potential energy surface sensitive to a balanced description of nondynamical and dynamical correlation. Recently, variational (MRCISD) and perturbative (MRPT2) approaches for including dynamical correlation in CASSCF-based calculations were tested along three representative ground state paths. Here, we use the same three paths to compare the performance of single-reference EOM-CC methods against MRCISD and MRCISD+Q We find that the spin-flip variant of EOM-CCSD with perturbative inclusion of triple excitations (dT or IT) produces potential energy profiles of the two lowest electronic states in quantitative agreement with MRCISD+Q (our highest-quality reference method). The nonparallelity errors and differences in vertical energy differences of the two surfaces along these scans are less than 1.4 kcal/mol (EOM-SF-CCSD(dT) versus MRCISD+Q). For comparison, the largest error of MRCISD versus MRCISD+Q is 1.7 kcal/mol. Our results show that the EOM-CC methods provide an alternative to multireference approaches and may be used to study photochemical systems like the one used in this work

On the Automatic Construction of QM/MM Models for Biological Photoreceptors: Rhodopsins as Model Systems

The automatic building of quantum mechanical/molecular mechanical models (QM/MM) of rhodopsins has been recently proposed. This is a prototype of an approach that will be expanded to make possible the systematic computational investigation of biological photoreceptors. QM/MM models represent useful tools for biophysical studies and for protein engineering, but have the disadvantage of being time-consuming to construct, error prone and, also, of not being consistently constructed by researchers operating in different laboratories. These basic issues impair the possibility to comparatively study hundreds of photoreceptors of the same family, as typically required in biological or biotechnological studies. Thus, in order to carry out systematic studies of photoreceptors or, more generally, light-responsive proteins, some of the authors have recently developed the Automatic Rhodopsin Modeling (ARM) protocol for the fast generation of combined QM/MM models of photoreceptors formed by a single protein incorporating in its cavity a single chromophore. In this chapter, we review the results of such research effort by revising the building protocol and benchmark studies and by discussing selected applications

Protocols Utilizing Constant pH Molecular Dynamics to Compute pH-Dependent Binding Free Energies

In protein–ligand binding, the electrostatic environments of the two binding partners may vary significantly in bound and unbound states, which may lead to protonation changes upon binding. In cases where ligand binding results in a net uptake or release of protons, the free energy of binding is pH-dependent. Nevertheless, conventional free energy calculations and molecular docking protocols typically do not rigorously account for changes in protonation that may occur upon ligand binding. To address these shortcomings, we present a simple methodology based on Wyman’s binding polynomial formalism to account for the pH dependence of binding free energies and demonstrate its use on cucurbit[7]­uril (CB[7]) host–guest systems. Using constant pH molecular dynamics and a reference binding free energy that is taken either from experiment or from thermodynamic integration computations, the pH-dependent binding free energy is determined. This computational protocol accurately captures the large p<i>K</i>_a shifts observed experimentally upon CB[7]:guest association and reproduces experimental binding free energies at different levels of pH. We show that incorrect assignment of fixed protonation states in free energy computations can give errors of >2 kcal/mol in these host–guest systems. Use of the methods presented here avoids such errors, thus suggesting their utility in computing proton-linked binding free energies for protein–ligand complexes