Electron-acoustic phonon field induced tunnel scattering

Theory of electron-acoustic single phonon scattering has been reconsidered. It is assumed that the non-degenerate semiconductor has a spherical parabolic band structure. In the basis of the reconsideration there is a phenomenon of the tilting of semiconductor bands by the perturbing potential of an electric field. In this case, electron eigenfunctions are not plane waves or Bloch functions. In low-field regime, the expressions for electron intraband transition probability and scattering time are obtained under elastic collision approximation. Dependencies of scattering time on electron energy and uniform electric field are analyzed. The results of corresponding numerical computations for n-Si at 300 K are presented. It is established that there is no fracture on the curve of electron scattering time dependence on the electron energy.Comment: 12 pages, 2 figure

ELECTRON MOBILITY NOISE SPECTRAL DENSITY AND VARIANCE IN A SEMICONDUCTOR

Abstract -The influence of external uniform electric field on the electron mobility variance in a non-degenerate n-type semiconductor is considered. In the course of analysis of results of mobility fluctuation theory, according to which electron mobility variance in equilibrium semiconductor equals infinity, it is shown that in the presence of uniform electric field the mobility variance becomes finite. The effect is explained in terms of the so-called electronphonon FIT (field-induced tunnel) scattering. The results of numerical computations of mobility variance dependence on the electric field for n-Si and n-Ge at 300 K are presented. It is revealed that mobility variance decreases by the logarithmic law with the electric field increase. The consideration of a mobility noise reciprocal problem established that the frequency dependence of mobility noise spectral density has a range of low-frequency plateau as well as ranges of 1/f and approximately 1/f dependencies. Low-frequency limit of 1/f dependence decreases to zero when the electric field tends to zero. A good agreement between mobility noise and current 1/fnoise in single crystal n-silicon is observed

May Measurement Month 2017: an analysis of blood pressure screening results in Armenia-Europe

Elevated blood pressure (BP) is a growing burden worldwide, leading to over 10 million deaths each year. May Measurement Month (MMM) is a global initiative aimed at raising awareness of high BP and to act as a temporary solution to the lack of screening programmes worldwide. An opportunistic cross-sectional survey of volunteers aged ≥18 was carried out in May 2017. Blood pressure measurement, the definition of hypertension and statistical analysis followed the standard MMM protocol. The study was conducted in public areas (14 sites in Yerevan and 18 in regions), both indoor and outdoor, as well as in 42 primary care centres. A total of 9199 individuals were screened during MMM17 of which 9186 had three BP measurements available. The mean age of screened individuals was 50 ± 16.7 years, 57.3% was female. At the time of screening 17.9% were on antihypertensive medication. After imputation, a percentage of participants with hypertension was 33.9%, and 52.9% of them were on treatment. Of those treated, 77.0% had uncontrolled BP. MMM17 was the largest BP screening campaign undertaken in Armenia. We found that in Armenia, untreated hypertension is common, as is not adequately treated hypertension

An analysis of blood pressure screening of 21 112 participants in Armenia: May Measurement Month 2018.

Elevated blood pressure (BP) is a growing burden worldwide and is the leading cause of mortality and disability-adjusted life years all over the world. May Measurement Month (MMM) is a global initiative aimed to raise awareness of high BP and to act as a temporary solution to the lack of screening programmes worldwide. An opportunistic cross-sectional survey of volunteers aged ≥18 was carried out in May to July 2018. Blood pressure measurement, the definition of hypertension (HTN) and statistical analysis followed the standard MMM protocol. The study was conducted in public areas (17 sites in Yerevan and 22 in regions), both indoor and outdoor, as well as in 78 primary care centres. A total of 21 112 individuals were screened during MMM18, of which 20 732 had three BP measurements available. The mean age of screened individuals was 46.2 ± 17.3 years, 57.8% were female. At the time of screening, 26.1% were on antihypertensive medication. After imputation, the percentage of participants with HTN was 38.7%, and 76.7% of them were aware of their high BP. Of participants receiving treatment, 47.1% had a controlled BP. MMM18 was the largest BP screening campaign undertaken in Armenia. We found that the proportion of HTN is substantial in Armenia, which may be a vital contributor to the growing burden of non-communicable diseases. Our results also suggest that untreated HTN is common and when treated still not adequately controlled in Armenia. The current situation, with an insufficient control rate of HTN, must be changed as soon as possible

Prognostic and preventive role of various factors in corneal rejection after keratoplasty

The literature review is devoted to the analysis of modern publications on the immunological and pathogenetic mechanisms of transplanted corneal rejection, risk factors, predictors and methods of the prevention of this complication. The prevention of corneal rejection is challenging.Currently, there is no single algorithm for the predicting methods of the corneal graft rejection, so further research in this area is needed.Purpose. To assemble the current data on immunological and non-immunological predictors of postoperative complications after keratoplasty. The analysis of modern publications on the immunological and pathogenetic mechanisms of corneal transplant rejection, risk factors, predictors and methods of prevention of this complication is presented. The databases used were CyberLeninka, PubMed, and Medline. The focus was on the publications of the last 10 year s.Conclusion. The data presented in the review make it possible to identify signs of corneal transplant rejection and to determine treatment in a timely manner, as well as to implement methods for preventing these complications

Comparative evaluation of chitosan-based multifunctional wound dressings: a multistage randomised controlled experimental trial

Background. Wounds of various aetiology are among the most frequent traumatic injuries. A prospective route to improve treatment of this nosology is the development of novel or advancement of the already on-stage dressing materials.Objectives. A comparative experimental assay of novel chitosan-based wound dressings in the healing of soft tissue wounds of different genesis using ultrasound to control biodegradation of the developed dosage form.Methods. Soft tissue wounds were modelled in experimental animals, conventional and lineage male rats, 275 (± 25) g body weight, and male rabbits, 2,900 (± 150) g weight, using a proprietary methodology (Patent on invention RU No. 2703709 dated 23 August, 2018).Two wound dressing samples selected as most promising and applicable in large-volume soft tissue aseptic wounds were tested in the final step of experiment. Ultrasound imaging of the model wound area during the sample material biodegradation was used to control the wound process in more detail. At all steps of experiment, animal models were handled in compliance with GOST 33044-2014 “Principles of Good Laboratory Practice”.Histomorphological assays were carried out with common protocols. Variation statistics was used for the data analysis, including the mean (M) and standard mean error (± m) estimation. The level of statistical significance was p < 0.05.Results. The animal assays and comprehensive evaluation of the obtained data revealed a high healing efficacy of chitosan-based wound coatings. The analyses of wound dressing samples have confirmed their predesigned properties: scaffold stability, capillarity, biodegradability and matrix capacities for the carried drug delivery.Additionally, ultrasound was proved effective to estimate dynamics of the coated wound healing and biopolymer biodegradation processes.Conclusion. The developed chitosan-based wound dressings exhibited efficacy in an experimental model of the soft tissues wound process.The use of ultrasound to study dynamics of the wound process and coating biodegradation provided an adequate congruence between the imaging and tissue histomorphology data, as well as the structure and properties of coating material

Влияние фотодинамической терапии на динамику раневого процесса у пациентов с гнойными заболеваниями пальцев и кисти

Despite the progress in modern surgery, the number of patients with purulent finger and hand diseases keeps growing these days in the clinical practice of surgeons. In recent years, there has been a tendency to develop more severe forms of panaritium and phlegmon in an increasingly young contingent of patients. Increasingly, doctors refuse to use the classical method of managing a postoperative wound of the hand involving the installation of drainage tubes. This phenomenon is polygenic and calls for special attention due to the frequent deplorable consequences of a treatment failure. The high urgency of this issue in Moscow Hospital No. 4 has become a rationale to study the effect of photodynamic therapy (PDT) on the course of the wound process in patients with this pathology.The purpose of this work is to develop a technique to advance the treatment outcomes for patients with purulent finger and hand diseases in case of open postoperative wound treatment.This study includes a comparative analysis of the wound process dynamics in 49 (49.5%) patients who underwent a photodynamic therapy session in the postoperative period and in 50 (50.5%) patients who received an open wound treatment after the operation. Photodynamic therapy was performed on the second postsurgical day by a laser apparatus “Atkus-2” (wave length 661 nm) with a gel form of the chlorinseries photosensitizer photoditazin in the form of an application at the rate of 1 g ml per 3–5 cm2 of the wound surface. The power density was chosen in the range of 0.1–1 W / cm2, and the time of exposure to the wound varied from 30 to 400 seconds, depending on the area of the wound.To assess the dynamics of the wound process in the postoperative period, we took measurements of all the patients’ wound areas on the 1st and 5th days, monitored the gross impression daily. In the patients who received PDT, we observed an earlier wound cleansing and remitting of the inflammatory process, acceleration of the edge epithelization, and earlier appearance of the granulation tissue by an average of 2 days. In the group of patients who were treated with PDT in the postoperative period, on the 5th day, the wound defect decreased by an average of 1 cm2, which amounted to 22.4%, in the control group – by 18%. The analysis of cytological and morphological patterns also revealed an accelerated switch from the inflammatory stage of the wound process to the reparative one - the reparative processes in the PDT group began earlier by 2 days. The microbiological analysis of wound exudate showed a downregulation of microflora after a PDT session - only in 6 cases pathogens were identified in the repeated seeding, which amounted to 12.24% of the group compared to 38% of the control group. After a session of photodynamic therapy, patients noted a significant reduction in pain, including during dressings. The pain syndrome immediately after the session decreased by 2–3 points. By the 5th day it became moderate – 4–5 points. In the control group, this indicator on the 2nd day was 8 points, decreasing by the 5th day to 6 points. For all analyzed indicators, the groups had statistically significant differences (p <0.001). Acceleration of postoperative wounds healing enabled to shorten the inpatient stay by 6 days and bring a vast improvement to the treatment quality for this group of patients, which allows considering photodynamic therapy as a high potential method for postoperative treatment of purulent finger and hand diseases.Несмотря на высокий уровень развития современной хирургии, в клинической практике современных хирургов продолжает расти количество пациентов с гнойными заболеваниями пальцев и кисти. В последние годы отмечается тенденция к развитию более тяжелых форм панарициев и флегмон у всё более молодого контингента больных. Все чаще врачи отказываются от использования классического метода ведения послеоперационной раны кисти с установкой дренажных трубок. Это явление полиэтиологично и требует особого внимания в связи с нередкими печальными последствиями неудачного лечениях. Высокая актуальность данной проблемы в ГБУЗ ГКБ № 4 г. Москвы стала основанием для проведения исследования влияния фотодинамической терапии (ФДТ) на течение раневого процесса у пациентов с данной патологией.Целью данной работы является разработка методики с использованием ФДТ для улучшения результатов лечения пациентов с гнойными заболеваниями кисти при открытом ведении послеоперационных ран.В данном исследовании проведен сравнительный анализ динамики раневого процесса у 99 больных, из них 49 (49,5%) пациентам в послеоперационном периоде выполняли курс ФДТ, 50 (50,5%) послеоперационную рану вели открытым способом. ФДТ выполняли на 2–е сутки после операции. Для ФДТ использовали гелевую форму фотодитазина (фотосенсибилизатор хлоринового ряда) в виде аппликации из расчета 1 мл геля на 3–5 см2 раневой поверхности. Сеанс облучения проводили с использованием лазерного аппарата «Аткус–2» (длина волны 661 нм). Плотность мощности составляла 0,1–1 Вт/см2, время воздействия на рану варьировали от 30 до 400 сек в зависимости от площади раны.Для оценки динамики раневого процесса в послеоперационном периоде всем пациентам выполняли измерение площади раневого дефекта на 1–е и 5–е сутки, ежедневный контроль макроскопической картины. У пациентов после выполнения ФДТ отмечено более раннее очищение раны и купирование воспалительного процесса, ускорение краевой эпителизации и более раннее появление грануляционной ткани в среднем на двое суток в сравнении с контрольной группой. В этой группе на 5–е сутки площадь раневого дефекта уменьшилась в среднем на 22,4% (1 см2), в контрольной группе – на 18%. При анализе цитологической и морфологической картин выявлено ускорение перехода от воспалительной стадии раневого процесса к репаративной: репаративные процессы в группе с ФДТ начинались раньше в среднем на двое суток, в сравнении с контрольной группой. При микробиологическом анализе раневого экссудата отмечалось снижение количества микрофлоры после курса ФДТ, лишь в 6 случаях (12,2%) в повторном посеве выявлены возбудители, в контрольной группе данный показатель составил 38%. После курса ФДТ больные отмечали существенное снижение болевого синдрома, в том числе и при перевязках. Болевой синдром сразу после курса ФДТ снижался на 2–3 балла, к 5–м суткам становился умеренным: 4–5 балла. В контрольной группе данный показатель на 2–е сутки составлял 8 баллов, снижаясь к 5–м суткам до 6 баллов. По всем анализируемым показателям группы имели статистически значимые различия (р<0,001).Ускорение заживления послеоперационных ран позволило сократить сроки стационарного пребывания на 6 суток и существенно улучшить качество лечения данной группы пациентов, что позволяет считать ФДТ высокоперспективным методом послеоперационного лечения гнойных заболеваний пальцев и кисти

Морфологический анализ местной тканевой реакции на подкожную имплантацию фрагментов ацеллюлярного дермального матрикса

Acellular dermal matrices (ADMs) are gaining popularity as surgical materials for operations on the pelvic organs, as well as in burn therapy and plastic surgery. Evaluation of the biocompatibility of surgical materials is an important and necessary step in the development of new ADMs.The aim of the study was to compare the results of subcutaneous implantation of ADM and native porcine skin in rats.Materials and methods. To obtain ADMs, detergent – enzymatic decellularization was used. On days 7, 14, 21, and 60 after the implantation of ADMs (the experimental group) and native porcine skin (the control group), the animals were removed from the experiment. The histologic sections were stained with hematoxylin – eosin and Masson’s trichrome stain, then an immunohistochemical reaction with antibodies to CD3 and CD68 was performed. Computer morphometry was carried out using the ImageJ software.Results. On day 7 after the implantation, moderate sterile inflammation in the experimental group and pronounced sterile inflammation with eosinophil infiltration in the control group were observed. On day 14 of the experiment, the samples from the experimental group were characterized by a relatively low content of macrophages and T-lymphocytes with insignificant edema and no signs of ADM biodegradation. The control group showed pronounced inflammation, a large number of infiltrating macrophages and T lymphocytes, as well as fragmentation of collagen fibers. On day 21 of the experiment, a thin capsule was formed around ADM, there was a small number of infiltrating T lymphocytes and macrophages, the collagen fibers of the implant were intact. In the samples of the control group, there was pronounced inflammation with the presence of a significant number of lymphocytes and macrophages, as well as fragmentation and vascularization of the implant. On day 60 of the experiment, no inflammatory response was observed around ADM, biodegradation was minimal, and a dense fibrous capsule was formed around the fragment of the native porcine skin.Conclusion. The experimental ADM has low immunogenicity and a low degree of biodegradation, which makes it possible to use it for further research to create efficient surgical material that is safe for use in clinical practice.Ацеллюлярные дермальные матриксы (АДМ) набирают большую популярность в качестве хирургических материалов при операциях на органах малого таза, в ожоговой терапии и пластической хирургии. Проверка биосовместимости материалов является важным и необходимым этапом при разработке новых АДМ.Цель исследования – провести сравнительный анализ результатов подкожной имплантации крысам АДМ и нативной дермы свиньи. Материалы и методы. Для получения АДМ использовали детергентно-энзиматический метод децеллюляризации. Через 7, 14, 21, 60 сут после имплантации АДМ (экспериментальная группа) и нативной дермы свиньи (контрольная группа) животных выводили из эксперимента. Гистологические срезы окрашивали гематоксилином и эозином, трихромом по Массону, выполняли иммуногистохимическую реакцию с антителами к CD3 и CD68. Компьютерную морфометрию проводили с помощью программы ImageJ.Результаты. На 7-е сут в экспериментальной группе отмечалось умеренное асептическое воспаление, в контрольной группе – выраженное асептическое воспаление с эозинофилами в инфильтрате. На 14-е сут в экспериментальной группе показано относительно низкое содержание макрофагов и Т-лимфоцитов с незначительным отеком, без биодеградации АДМ. В контрольной группе выявлено выраженное воспаление, инфильтрация большим количеством макрофагов и Т-лимфоцитов, а также фрагментация коллагеновых волокон. На 21-е сут вокруг АДМ сформировалась тонкая капсула, в инфильтрате малое количество Т-лимфоцитов и макрофагов, коллагеновые волокна имплантата были интактны. В образцах контрольной группы – выраженное воспаление с присутствием значительного количества лимфоцитов и макрофагов, фрагментация и васкуляризация имплантата. На 60-е сут вокруг АДМ воспалительной реакции не наблюдалось, биодеградация была минимальной, вокруг фрагмента нативной дермы свиньи сформировалась плотная фиброзная капсула.Заключение. Разработанный АДМ обладает низкой иммуногенностью и малой степенью биодеградации. Это позволяет использовать данную конструкцию для дальнейших исследований по созданию полноценного хирургического материала, безопасного для применения в клинической практике

CpG-island methylation study of liver fluke-related cholangiocarcinoma

Background: Genetic changes have been widely reported in association with cholangiocarcinoma (CCA), while epigenetic changes are poorly characterised. We aimed to further evaluate CpG-island hypermethylation in CCA at candidate loci, which may have potential as diagnostic or prognostic biomarkers. Methods: We analysed methylation of 26 CpG-islands in 102 liver fluke related-CCA and 29 adjacent normal samples using methylation-specific PCR (MSP). Methylation of interest loci was confirmed using pyrosequencing and/or combined bisulfite restriction analysis, and protein expression by immunohistochemistry. Results: A number of CpG-islands (OPCML, SFRP1, HIC1, PTEN and DcR1) showed frequency of hypermethylation in >28% of CCA, but not adjacent normal tissues. The results showed that 91% of CCA were methylated in at least one CpG-island. The OPCML was the most frequently methylated locus (72.5%) and was more frequently methylated in less differentiated CCA. Patients with methylated DcR1 had significantly longer overall survival (Median; 41.7 vs 21.7 weeks, P=0.027). Low-protein expression was found in >70% of CCA with methylation of OPCML or DcR1. Conclusion: Aberrant hypermethylation of certain loci is a common event in liver fluke-related CCA and may potentially contribute to cholangiocarcinogenesis. The OPCML and DcR1 might serve as methylation biomarkers in CCA that can be readily examined by MSP

Применение фотодинамической терапии в комплексном лечении гнойных заболеваний кисти

For many years, the treatment of purulent diseases of the hand has stayed relevant. Despite the progress in modern medicine, this pathology retains its prevalence and, most importantly, is often found in patients of the working age, which determines the socio-economic importance of the search for new approaches to the treatment of purulent diseases of this localization. In the purulent surgery department of State Clinical hospital № 4, a study and treatment of two groups of patients were carried out: patients with phlegmons and felons of the hand with open management of postoperative wounds using traditional treatment methods (antibiotic therapy, immobilization, dressings with antiseptic solutions and ointments, the use of wound enzymes) and with the use of photodynamic therapy (PDT) in the postoperative period. PDT was performed on the second or third day after opening the phlegmon or felon using an ATKUS-2 semiconductor laser (AO “Poluprovodnikovye pribory”, Russia) with an output power of 1 to 2 W, an operating wavelength of 660 ± 0.03 nm and an energy density between 20 and 25 J/cm² after application of the photosensitizer based on chlorin e6 to the treated wound area. The article describes the technique of PDT in patients with purulent diseases of the hand. It was found that it is optimal to perform PDT as early as possible after the operation period, but not earlier than on the second day after the operation, because earlier dressing is especially painful in the absence of sutures and can lead to bleeding from a postoperative wound when the dressing is removed. The effectiveness of treatment in the studied groups was evaluated: the terms of inpatient healing in the groups were compared; the dynamics of the course of the wound process was analyzed. When comparing the results of the two groups, a significant acceleration in the healing of the postoperative wounds was noted in patients for whom PDT was used – 5 days (1.4 times) faster compared to treatment according to the generally accepted technique. The early appearance of granulations and the antibacterial effect of this procedure are noted, which significantly improves the treatment outcome for this pathology. This makes the use of PDT relevant and appropriate in the complex treatment of purulent diseases of the handМногие годы не теряют актуальности вопросы лечения гнойных заболеваний кисти. Несмотря на прогресс в современной медицине, данная патология сохраняет свою распространенность и, что наиболее важно, часто встречается у пациентов трудоспособного возраста, что обуславливает социально-экономическую важность поиска новых подходов к лечению гнойных заболеваний данной локализации. На базе отделения гнойной хирургии ГБУЗ ГКБ № 4 проведено исследование и лечение двух групп больных: пациентов с флегмонами и панарициями кисти при открытом ведении послеоперационных ран при применении традиционных методик лечения (антибактериальная терапия, иммобилизация, повязки с антисептическими растворами и мазями, применение раневых ферментов) и с применением в послеоперационном периоде фотодинамической терапии (ФДТ). ФДТ выполняли на вторые-третьи сутки после вскрытия флегмоны или панариция с использованием полупроводникового лазерного аппарата «АТКУС-2» (АО «Полупроводниковые приборы», Россия) с выходной мощностью от 1 до 2 Вт, рабочей длиной волны 660±0,03 нм и плотностью энергии от 20 до 25 Дж/см² после аппликации на обрабатываемую раневую область фотосенсибилизатора на основе хлорина е6.В статье описана методика проведения ФДТ у пациентов с гнойными заболеваниями кисти. Установлено, что оптимально проводить ФДТ в максимально ранние сроки после операционного периода, но не ранее, чем на вторые сутки после операции, так как перевязка в более ранние сроки особенно болезненна в условиях отсутствия швов и может привести к кровотечению из послеоперационной раны при удалении повязки. Проведена оценка эффективности лечения в исследуемых группах: выполнены сравнение сроков стационарного заживления в группах, проведен анализ динамики течения раневого процесса. При сравнении результатов терапии отмечено достоверное ускорение в 1,4 раза (на 5 суток) заживления послеоперационных ран у пациентов, у которых применялась ФДТ, по сравнению с лечением по общепринятой методике. Отмечено раннее появление грануляций и антибактериальный эффект ФДТ, что существенно улучшает результат лечения данной патологии. Это делает применение ФДТ актуальным и целесообразным в комплексном лечении гнойных заболеваний кисти