ROCK SURFACE CHARACTERIZATION BY IMMERSION CALORIMETRY: WETTABILITY AND SPECIFIC SURFACE AREA

ABSTRACT Petrophysical properties such as wettability and surface area control hydrocarbon storage and transport properties. In the work being reported in this paper, we present the theoretical aspects as well as experimental technique and results of testing and validating a proposed calorimetry technique for specific surface area and wettability characterization. Identical immersion calorimetry experiments with slightly different initial conditions of the sample are analyzed to obtain these two properties of a core sample. Validation of the experimental technique is an important step, which is performed in this work by comparing the surface areas of the samples obtained by the proposed technique with the surface area obtained by the well-known Brunauer-EmmettTaylor (BET) gas-adsorption technique. Surface area measurements are performed on a set of core plugs and reference samples, including hydrophilic and hydrophobic powders of pure substances, minerals, and clays

Crystal and Electronic Structures of Alluaudite-Type Double Molybdates of Scandium and Indium

Double molybdates of indium and scandium with alluaudite structure are prepared by the solid-phase synthesis method. The crystal structure of the indium containing compound is refined and optical characteristics of Na5R(Mo04)4(R = Sc, In) are determined. Electronic structures of Na5R(Mo04)4(R = Sc, In) molybdates are studied within the ab initio method taking account of Na/Sc(In) positional disordering. Calculations of the imaginary part of dielectric function predict the optical gap of ~3.8 eV, in accordance with absorption spectroscopy data. It is established that formation energy of sodium vacancies strongly depends on sodium position and Sc(In) concentration. As a result, various diffusion mechanisms may be activated in alluaudite-type compounds with high and low contents of metal R. © 2019, Pleiades Publishing, Ltd

Эксплуатационные свойства катализаторов неэкстракционной окислительной демеркаптанизации нефти и нефтяных фракций

The results of identification of the main operational properties of metallocomplex catalysts solutions for non-extractive oxidative sweetening of natural hydrocarbons and their products are provided in this article. These catalysts allow carrying out the catalytic oxidation of hydrogen sulfide and mercaptans in hydrocarbon media directly. This method allows to exclude from the technological cycle the need to use large volumes of extracting agents (aqueous alkaline solutions), which greatly simplifies the purification technology and eliminates the stage of recycling sulfuralkaline waste. These catalysts are oxidizing systems, which can have a negative impact on their storage and use. Therefore, it was necessary to determine the influence of the synthesis conditions and the composition of the catalyst solution on viscosity, pour point, surface tension and corrosion properties. The impact of storage duration and its conditions on the catalysts activity in the oxidation of H2S and light mercaptans in oil and oil products was studied. The results showed that the catalytic systems based on copper salts and amino alcohols correspond to the requirements for industrial applications.В статье приведены экспериментальные результаты по определению основных эксплуатационных характеристик растворов металлокомплексных катализаторов неэкстракционной окислительной демеркаптанизации природных углеводородов и продуктов их переработки. Определено влияние режима синтеза и состава раствора катализатора на вязкость, температуру потери текучести, поверхностное натяжение и коррозионные свойства. Изучено влияние длительности и режимов хранения на активность катализаторов в реакции окисления сероводорода и легких меркаптанов (метил-, этилмеркаптан) в нефти и нефтепродуктах

MEDICAL AND SOCIAL CHARACTERISTICS OF WOMEN OF YOUNG REPRODUCTIVE AGE AFTER HYSTERECTOMY

Background. In many countries, hysterectomy is one of the most frequently performed surgical procedures.The objective of our analysis was to assess the social and medical characteristics of young reproductive-age patients who underwent hysterectomy.Materials and methods. A retrospective study involved 140 women aged 18–35 years (median age 29.4 ± 4.7 years) who underwent emergency or elective hysterectomy in the hospitals of Zabaykalsky Krai for a period of 5 years (January 1, 2013, to December 31, 2017).Results. 51.4 % of patients were housewives; 52.9 % were single; 55.7 % had bad habits (smoking, alcohol consumption). These women had a high incidence of socially significant infections: HIV – 3.6 %, active forms of tuberculosis – 1.5 %. 89.3 % of hysterectomies were emergent and 10.7 % were elective (p = 0.0001; OR = 69.4; 95% CI 32.6–148.1). The indications for the emergency hysterectomy were uterine myoma (80 %) and cervical or ovarian cancer (20 %). The obstetrical complications were the main indications for the emergency surgery: placenta abruption – 24.0 %; placenta previa – 20.8 % (placenta increta and/or percreta – 16.8 %; massive antenatal bleeding – 4.0 %); postpartum hemorrhage after vaginal delivery and caesarean section 19.2 %; septic and/or hemorrhagic shock in early miscarriages (from 8 to 19 weeks of gestation) 15.2 %. Mortality was registered in case of emergency hysterectomy only (4.3 %). Half of the deaths (50 %) occurred in cases of complicated miscarriages.Conclusion. To preserve the reproductive potential of young women of reproductive age, it is necessary to increase their social and cultural level, and responsibility for their own health and gender behavior

Каталитическая очистка мазута от сероводорода и меркаптанов

Increasing environmental regulations according to the content of toxic volatile sulfur impurities in fuel oil requires improvement existing and development of new absorbers and ways of their application. The results of the study of oxidative demercaptanization of model mixtures containing hydrogen sulfide and hydrogen sulfide/ethyl mercaptan in the presence of metal complex catalysts are shown. It is established that the required degree of purification (conversion of hydrogen sulphide) is achieved at a ratio of kt/H2S=1.5, which is much lower than required when using scavenger. Experiments carried out at the refinery of "TAIF-NK" to remove hydrogen sulfide from fuel oil have shown the efficiency close to that obtained in experiments on model compounds. These catalysts are also effective in conversion of light mercaptans of fuel oil. Irreversible nature of transformation of hydrogen sulfide and thiols into nontoxical forms and no negative impact on the properties of the final product of this method is established.Показана возможность очистки мазута от токсичных легколетучих сернистых примесей в результате их каталитического окисления кислородом воздуха в присутствии металло-комплексов переходных металлов

Redox-Dependent Stability, Protonation, and Reactivity of Cysteine-Bound Heme Proteins

Cysteine-bound hemes are key components of many enzymes and biological sensors. Protonation (deprotonation) of the Cys ligand often accompanies redox transformations of these centers. To characterize these phenomena, we have engineered a series of Thr78Cys/Lys79Gly/Met80X mutants of yeast cytochrome c (cyt c) in which Cys78 becomes one of the axial ligands to the heme. At neutral pH, the protonation state of the coordinated Cys differs for the ferric and ferrous heme species, with Cys binding as a thiolate and a thiol, respectively. Analysis of redox-dependent stability and alkaline transitions of these model proteins, as well as comparisons to Cys binding studies with the minimalist heme peptide microperoxidase-8, demonstrate that the protein scaffold and solvent interactions play important roles in stabilizing a particular Cys–heme coordination. The increased stability of ferric thiolate compared with ferrous thiol arises mainly from entropic factors. This robust cyt c model system provides access to all four forms of Cys-bound heme, including the ferric thiol. Protein motions control the rates of heme redox reactions, and these effects are amplified at low pH, where the proteins are less stable. Thermodynamic signatures and redox reactivity of the model Cys-bound hemes highlight the critical role of the protein scaffold and its dynamics in modulating redox-linked transitions between thiols and thiolates

Protein docking prediction using predicted protein-protein interface

<p>Abstract</p> <p>Background</p> <p>Many important cellular processes are carried out by protein complexes. To provide physical pictures of interacting proteins, many computational protein-protein prediction methods have been developed in the past. However, it is still difficult to identify the correct docking complex structure within top ranks among alternative conformations.</p> <p>Results</p> <p>We present a novel protein docking algorithm that utilizes imperfect protein-protein binding interface prediction for guiding protein docking. Since the accuracy of protein binding site prediction varies depending on cases, the challenge is to develop a method which does not deteriorate but improves docking results by using a binding site prediction which may not be 100% accurate. The algorithm, named PI-LZerD (using Predicted Interface with Local 3D Zernike descriptor-based Docking algorithm), is based on a pair wise protein docking prediction algorithm, LZerD, which we have developed earlier. PI-LZerD starts from performing docking prediction using the provided protein-protein binding interface prediction as constraints, which is followed by the second round of docking with updated docking interface information to further improve docking conformation. Benchmark results on bound and unbound cases show that PI-LZerD consistently improves the docking prediction accuracy as compared with docking without using binding site prediction or using the binding site prediction as post-filtering.</p> <p>Conclusion</p> <p>We have developed PI-LZerD, a pairwise docking algorithm, which uses imperfect protein-protein binding interface prediction to improve docking accuracy. PI-LZerD consistently showed better prediction accuracy over alternative methods in the series of benchmark experiments including docking using actual docking interface site predictions as well as unbound docking cases.</p

Experimental detection of short regulatory motifs in eukaryotic proteins: tips for good practice as well as for bad

It has become clear in outline though not yet in detail how cellular regulatory and signalling systems are constructed. The essential machines are protein complexes that effect regulatory decisions by undergoing internal changes of state. Subcomponents of these cellular complexes are assembled into molecular switches. Many of these switches employ one or more short peptide motifs as toggles that can move between one or more sites within the switch system, the simplest being on-off switches. Paradoxically, these motif modules (termed short linear motifs or SLiMs) are both hugely abundant but difficult to research. So despite the many successes in identifying short regulatory protein motifs, it is thought that only the “tip of the iceberg” has been exposed. Experimental and bioinformatic motif discovery remain challenging and error prone. The advice presented in this article is aimed at helping researchers to uncover genuine protein motifs, whilst avoiding the pitfalls that lead to reports of false discovery. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12964-015-0121-y) contains supplementary material, which is available to authorized users

Mobilise-D insights to estimate real-world walking speed in multiple conditions with a wearable device

This study aimed to validate a wearable device’s walking speed estimation pipeline, considering complexity, speed, and walking bout duration. The goal was to provide recommendations on the use of wearable devices for real-world mobility analysis. Participants with Parkinson’s Disease, Multiple Sclerosis, Proximal Femoral Fracture, Chronic Obstructive Pulmonary Disease, Congestive Heart Failure, and healthy older adults (n = 97) were monitored in the laboratory and the real-world (2.5 h), using a lower back wearable device. Two walking speed estimation pipelines were validated across 4408/1298 (2.5 h/laboratory) detected walking bouts, compared to 4620/1365 bouts detected by a multi-sensor reference system. In the laboratory, the mean absolute error (MAE) and mean relative error (MRE) for walking speed estimation ranged from 0.06 to 0.12 m/s and − 2.1 to 14.4%, with ICCs (Intraclass correlation coefficients) between good (0.79) and excellent (0.91). Real-world MAE ranged from 0.09 to 0.13, MARE from 1.3 to 22.7%, with ICCs indicating moderate (0.57) to good (0.88) agreement. Lower errors were observed for cohorts without major gait impairments, less complex tasks, and longer walking bouts. The analytical pipelines demonstrated moderate to good accuracy in estimating walking speed. Accuracy depended on confounding factors, emphasizing the need for robust technical validation before clinical application. Trial registration: ISRCTN – 12246987