Linearized force constants method for lattice dynamics in mixed semiconductors

A simple and accurate method of calculating phonon spectra in mixed semiconductors alloys, on the basis of preliminarily (from first principles) relaxed atomic structure, is proposed and tested for (Zn,Be)Se and (Ga,In)As solid solutions. The method uses an observation that the interatomic force constants, calculated ab initio for a number of microscopic configurations in the systems cited, show a clear linear variation of the main (diagonal) values of the interatomic force constants with the corresponding bond length. We formulate simple rules about how to recover the individual 3x3 subblocks of the force constants matrix in their local (bonds-related) coordinate systems and how to transform them into a global (crystal cell-related) coordinate system. Test calculations done for 64-atom supercells representing different concentrations of (Zn,Be)Se and (Ga,In)As show that the phonon frequencies and compositions of eigenvectors are faithfully reproduced in a linearized force constants calculation, as compared to true ab initio calculations.Comment: to appear in the proceedings of the Phonons2007 conference (Paris, July 2007

The Role Of Corporate Governance Characteristics In Improving The Liquidity And Profitability Of Banks During The Reconstruction Phase. (An applied study in private banks in Lattakia Governorate)

The study aimed to demonstrate the role of corporate governance characteristics in improving the liquidity and profitability of banks during the reconstruction phase, by conducting an applied study in Syrian private banks, by assessing the reality of each of the disclosure, transparency, accountability, work discipline and validity, the researcher relied on the deductive approach as an approach In thinking, the descriptive approach has a procedural approach to determine the availability of corporate governance characteristics in private banks. Where the researcher distributed a questionnaire to 149 workers, the study concluded that the lowest mean average for the responses of the sample members to the phrases that measure the delegated participation of decision-making workers is 2.95, and it is less than the mean of neutrality 3, and it is significant, meaning that the bank does not have the good ability to fulfill its liabilities Traded according to the answers of the sample members. At the lowest levels, this affects the bank’s business mechanism, which is reflected in its liquidity. Then some proposals were presented, the most important of which was the necessity for the bank to work on disclosure and transparency, and to commit to disclosing the structure and policies of governance and the extent of their application. هدفت الدِّراسة إلى بيان دور خصائص حوكمة الشركات في تحسين سيولة وربحية المصارف خلال مرحلة إعادة الإعمار من خلال إجراء دراسة تطبيقية في المصارف الخاصة في محافظة اللاذقية- مصرف سورية والمهجر نموذجاً، وذلك من خلال تقييم واقع كل من الإفصاح والشفافية، والمساءلة، الانضباط بالعمل والصلاحية. اعتمدت الباحثة على المقاربة الاستنباطية كمنهج في التفكير، وعلى المنهج الوصفي كمنهج إجرائي للوقوف على مدى توافر خصائص حوكمة الشركات في المصارف الخاصة المدروسة. قامت الباحثة بتوزيع استبانة على 149 عامل، وقد خلصت الدِّراسة إلى أن أقل متوسط حسابي لإجابات أفراد العينة على العبارات التي تقيس تفويض مشاركة العاملين اتخاذ القرار هو 2.95، وهو أقل من متوسّط الحياد 3، ومعنوي، أي أنّ المصرف لا يتميز بالقدرة الجيدة للوفاء بمطلوباته المتداولة وفق إجابات أفراد العينة في أقل المستويات، وهذا يؤثر على آلية عمل المصرف الأمر الذي ينعكس على سيولته. وقدمت الباحثة بعض المقترحات كان أهمها ضرورة أن يعمل المصرف على الإفصاح والشفافية، وأن يلتزم بالإفصاح عن هيكل وسياسات الحوكمة ومدى تطبيقها

Macroprudential policy and financial stability, role and tools

The aim of macroprudential policy is to ensure financial stability by avoiding the outbreak of banking crises, which have a dangerous effect on the economy. Is macroprudential policy effective in the face of banking crises and systemic risks? Macroprudential policy has received significant interest from policy-makers and researchers. A few developing countries were using macroprudential policy tools well before the 2008 financial crisis, but significant progress has been made thereafter in both emerging and industrialized economies to put in place specific institutional settings for macroprudential policy

Firm growth vs. external growth: a behavioral approach

A firm is a market contradiction: as a firm grows, the market shrinks. The basis of this statement are theoretical approaches, which are called theories of the company. This work is aimed at determining the boundaries of the company in a dynamic perspective with the aim of finding effective solutions to the process of its growth. The study notes that opportunism as a behavioral factor, as Williamson noted, incurs significant operating costs that encourage the firm to change its boundaries

Inhaled carbon monoxide protects against the development of shock and mitochondrial injury following hemorrhage and resuscitation

Aims: Currently, there is no effective resuscitative adjunct to fluid and blood products to limit tissue injury for traumatic hemorrhagic shock. The objective of this study was to investigate the role of inhaled carbon monoxide (CO) to limit inflammation and tissue injury, and specifically mitochondrial damage, in experimental models of hemorrhage and resuscitation. Results: Inhaled CO (250 ppm for 30 minutes) protected against mortality in severe murine hemorrhagic shock and resuscitation (HS/R) (20% vs. 80%; P<0.01). Additionally, CO limited the development of shock as determined by arterial blood pH (7.25±0.06 vs. 7.05±0.05; P<0.05), lactate levels (7.2±5.1 vs 13.3±6.0; P<0.05), and base deficit (13±3.0 vs 24±3.1; P<0.05). A dose response of CO (25-500 ppm) demonstrated protection against HS/R lung and liver injury as determined by MPO activity and serum ALT, respectively. CO limited HS/R-induced increases in serum tumor necrosis factor-α and interleukin-6 levels as determined by ELISA (P<0.05 for doses of 100-500ppm). Furthermore, inhaled CO limited HS/R induced oxidative stress as determined by hepatic oxidized glutathione:reduced glutathione levels and lipid peroxidation. In porcine HS/R, CO did not influence hemodynamics. However, CO limited HS/R-induced skeletal muscle and platelet mitochondrial injury as determined by respiratory control ratio (muscle) and ATP-linked respiration and mitochondrial reserve capacity (platelets). Conclusion: These preclinical studies suggest that inhaled CO can be a protective therapy in HS/R; however, further clinical studies are warranted

New data on the level of immune stratum against Q fever agent in population of the of Republic of Guinea

which is bacteria of the species Coxiella burnetii. One of the factors showing the possibility of pathogen circulation in a certain territory is assessed by the presence of an immune stratum in the inhabitants of the region. In the 1980s, the study of the immune structure of the population of the Republic of Guinea in relation to coxiellosis has begun. The present study, carried out in 2015—2019, has been aimed to obtain new information about the immune stratum of the population of the Republic of Guinea against the causative agent of Q fever and to compare it with previous studies. Specific IgG antibodies in the blood of the Guinea residents were detected by using enzyme-linked immunosorbent assay (ELISA) with a set of reagents manufactured at the St. Petersburg Pasteur Institute (St. Petersburg, Russian Federation). The serum samples were tested in at 1:100 dilution. Antibodies against C. burnetii were detected in 124/2346 (5.3% [CI 4.5-6.3]) samples. This study confirms the previously obtained data on the circulation of the causative agent of coxiellosis in all landscape and geographical zones of the Republic of Guinea. The natural and climatic conditions of the region, the variety of ixodic tick species currently inhabiting this territory being a reservoir and vector of infection, as well as a large amount of livestock are the factors for active circulation of the Q fever pathogen and the emergence of related disease outbreaks. The data obtained necessitate continuing further studies on distribution of C. burnetii in the territory of the Republic of Guinea. Taking into consideration the epidemiological significance of Q fever, a pressing task is to study a proportion of this infectious disease in the overall structure of diseases registered in the territory of the Republic of Guinea. It is also necessary to conduct regular epizootological monitoring in order to clarify the types of carriers and vectors of C. burnetii in different landscape and geographical zones of the Republic of Guinea as well as to assess the immune stratum against the pathogen in large and small cattle being the main sources of infection for humans. The data obtained will allow us to determine presence of a natural focus of this infection as well as its borders and develop a set of preventive (anti-epidemic) measures

Identification of the Farm Animals Immune to Pathogens of Zoonotic Infectious Diseases in the Republic of Guinea

The most common anthropozoonoses on the African continent are coxiellosis and Rift Valley fever. It is known that detection of specific IgG antibodies in the blood sera of farm animals is one of the indicators of the pathogen circulation in a certain territory. The aim of the work was to identify specific IgG antibodies in the blood sera of farm animals collected on the territory of the Republic of Guinea to pathogens of zoonotic infectious diseases: coxiellosis, brucellosis, glanders, CCHF, West Nile and Rift Valley fevers, using enzyme immunoassay (ELISA). Materials and methods. A panel of 970 samples of blood sera from farm animals inhabiting all landscape-geographical zones of Guinea was compiled for the work. Identification of specific antibodies was carried out using enzyme immunoassay with preparations recommended for veterinary studies. Results and discussion. Specific antibodies to zoonoses were detected in 700 out of 1074 samples (65.2 % of the total), including: to Coxiella burnetii – in 172 (16.0 %); to Brucella spp. – in 212 (19.7 %); viruses of Rift Valley fever – 85 (7.9 %); CCHF – in 139 (12.9 %) and West Nile fever – in 92 (8.6 %). Antibodies to Burkholderia mallei were not found in the tested material. Positive samples were registered in all landscape-geographical zones. Thus, an urgent task is to continue studying the circulation of pathogens of zoonoses and anthropozoonoses in the territory of the Republic of Guinea and to organize regular monitoring over the spread of zoonotic infectious diseases in collaboration with veterinary services, which will allow timely forecasting and coordinating prophylactic (anti-epidemic) measures to prevent cases of diseases

Detection of Crimean-Congo Hemorrhagic Fever Virus Markers in Samples of Ixodes Ticks Collected in the Territory of the Republic of Guinea

Objective of the study. This work was carried out to identify markers (antigen and RNA) of CrimeanCongo hemorrhagic fever (CCHF) virus in samples from ticks, collected in all landscape-geographical areas of Guinea: Lower, Middle, Upper and Forest, to obtain up-to-date data on the distribution of the pathogen in the country.Materials and methods. Total of 4276 specimens of 8 species of ticks collected in 2016–2019 in the territory of the Republic of Guinea were studied, which were compiled into 1406 samples. Ectoparasites were collected from livestock animals, dogs, and small mammals. Viral antigen was detected using enzyme immunoassay (ELISA). The presence of RNA of the CCHF virus was determined by reverse transcription polymerase chain reaction (RT-PCR).Results and discussion. As a result of the studies, the antigen of the CCHF virus was detected in 21 samples (1.5 %), and RNA – in 37 (2.6 %). All samples, in which the viral antigen was detected, contained RNA of the CCHF virus. Positive results were obtained in samples from all geographical areas of the country. The main vectors and reservoirs of the pathogen in Guinea are ticks of the species Rh. sanguineus, Rh. geigyi, Rh. annulatus and Am. variegatum. The data obtained confirm the previously available information on the possibility of the pathogen circulation in this region and determine the need for further study of the spread of the CCHF virus in the territory of the Republic of Guinea

Molecular mechanisms and cellular functions of cGAS-STING signalling

The cGAS–STING signalling axis, comprising the synthase for the second messenger cyclic GMP–AMP (cGAS) and the cyclic GMP–AMP receptor stimulator of interferon genes (STING), detects pathogenic DNA to trigger an innate immune reaction involving a strong type I interferon response against microbial infections. Notably however, besides sensing microbial DNA, the DNA sensor cGAS can also be activated by endogenous DNA, including extranuclear chromatin resulting from genotoxic stress and DNA released from mitochondria, placing cGAS–STING as an important axis in autoimmunity, sterile inflammatory responses and cellular senescence. Initial models assumed that co-localization of cGAS and DNA in the cytosol defines the specificity of the pathway for non-self, but recent work revealed that cGAS is also present in the nucleus and at the plasma membrane, and such subcellular compartmentalization was linked to signalling specificity of cGAS. Further confounding the simple view of cGAS–STING signalling as a response mechanism to infectious agents, both cGAS and STING were shown to have additional functions, independent of interferon response. These involve non-catalytic roles of cGAS in regulating DNA repair and signalling via STING to NF-κB and MAPK as well as STING-mediated induction of autophagy and lysosome- dependent cell death. We have also learnt that cGAS dimers can multimerize and undergo liquid–liquid phase separation to form biomolecular condensates that could importantly regulate cGAS activation. Here, we review the molecular mechanisms and cellular functions underlying cGAS–STING activation and signalling, particularly highlighting the newly emerging diversity of this signalling pathway and discussing how the specificity towards normal, damage-induced and infection-associated DNA could be achieved