INVESTIGATION OF THE INFLUENCE OF DIFFERENT MODIFIERS ON THE CORROSION RATE OF ALSI18CU3CRMN ALLOY

The development of new hypereutectic Al-Si alloys with increased mechanical and improved operational properties is an up-to-date engineering task. The non-standardized hypereutectic aluminum-silicon alloy AlSi18Cu3CrMn is modified with different modifiers (standard modifier P and a complex of modifiers P, Ti, B and Be). The compositions thus modified are subjected to heat treatment (T6). Artificial aging after quenching was carried out under different parameters (temperature and time). The aim of the present study is to determine the influence of the used modifiers on the corrosion rate of the compositions under the same conditions. The gravimetric method was used.

Skeletal Muscle Gender Dimorphism from Proteomics

Gross contraction in skeletal muscle is primarily determined by a relatively small number of contractile proteins, however this tissue is also remarkably adaptable to environmental factors1 such as hypertrophy by resistance exercise and atrophy by disuse. It thereby exhibits remodeling and adaptations to stressors (heat, ischemia, heavy metals, etc.)2,3. Damage can occur to muscle by a muscle exerting force while lengthening, the so-called eccentric contraction4. The contractile proteins can be damaged in such exertions and need to be repaired, degraded and/or resynthesized; these functions are not part of the contractile proteins, but of other much less abundant proteins in the cell. To determine what subset of proteins is involved in the amelioration of this type of damage, a global proteome must be established prior to exercise5 and then followed subsequent to the exercise to determine the differential protein expression and thereby highlight candidate proteins in the adaptations to damage and its repair. Furthermore, most studies of skeletal muscle have been conducted on the male of the species and hence may not be representative of female muscle

Personality Characteristics and Informal Leadership Among Young People With Mild and Moderate Degree of Intellectual Disability

Настоящата статия представя резултати от проведени количествени и качествени изследвания сред млади хора с лека до умерена степен на интелектуално затруднение на възраст 18 – 40 години, посещаващи Дневен център за трудови умения. Целта на изследването е да се идентифицират неформалните лидери, да се опишат личностните им характеристики, и особеностите на лидерството сред тази група. Използваните методи са: социометрично изследване, цветови тест на Люшер и Личностен въпросник на Айзенк. Събраните данни и анализираните резултатите сочат, че степента на интелектуално затруднение не влияе върху избора на неформален лидер. Определящи характеристики са мотивацията за самоусъвършенстване и налагане на собствения авторитет сред другите (определени по цветови тест на Люшер), както и ниските показатели по скала „Невротизъм“ от Личностния въпросник на Айзенк.This article presents the results of qualitative and quantitative studies conducted among young people with mild to moderate intellectual disability, aged 18-40 who attended a Daycare center for working skills. The aim of the study was to identify the informal leaders among the participants and to describe some leadership features in this group. The used methods were a sociomertic study, the Lüscher color-test and the Eysenck Personality Inventory. The summarized results showed that the degree of intellectual disability did not affect the choice of an informal leader. The important determinants were the motivation for self-improvement and imposing authority among others (found by means of Lüscher color test), and the low scores on scale "Neuroticism" from Eysenck Personality Inventory.Language: Bulgaria

Dietary Fish Oil Supplement Induces Age-Specific Contractile and Proteomic Responses in Muscles of Male Rats

Background: Dietary fish oil (DFO) has been identified as a micronutrient supplement with the potential to improve musculoskeletal health in old age. Few data are available for effects of DFO on muscle contractility, despite the significant negative impact of muscle weakness on age-related health outcomes. Accordingly, the effects of a DFO intervention on the contractile function and proteomic profile of adult and aged in an animal model of aging were investigated. Methods: This preliminary study evaluated 14 adult (8 months) and 12 aged (22 months) male, Sprague-Dawley rats consuming a DFO-supplemented diet or a control diet for 8 weeks (7 adult and 6 aged/dietary group). Animal weight, food intake and grip strength were assessed at the start and end of the FO intervention. In situ force and contractile properties were measured in the medial gastrocnemius muscle following the intervention and muscles were processed for 2-D gel electrophoresis and proteomic analysis via liquid chromatography with tandem mass spectrometry, confirmed by immunoblotting. Effects of age, diet and age x diet interaction were evaluated by 2- way ANOVA. Results: A significant (P = 0.022) main effect for DFO to increase (~ 15%) muscle contractile force was observed, without changes in muscle mass. Proteomic analysis revealed a small number of proteins that differed across age and dietary groups at least 2-fold, most of which related to metabolism and oxidative stress. In seven of these proteins (creatine kinase, triosephosphate isomerase, pyruvate kinase, parvalbumin, beta-enolase, NADH dehydrogenase and Parkin7/DJ1), immunoblotting corroborated these findings. Parvalbumin showed only an effect of diet (increased with DFO) (P = 0.003). Significant age x diet interactions were observed in the other proteins, generally demonstrating increased expression in adult and decreased expression aged rats consuming DFO (all P \u3e 0.011). However, correlational analyses revealed no significant associations between contractile parameters and protein abundances. Conclusions: Results of this preliminary study support the hypothesis that DFO can enhance musculoskeletal health in adult and aged muscles, given the observed improvement in contractile function. The fish oil supplement also alters protein expression in an age-specific manner, but the relationship between proteomic and contractile responses remains unclear. Further investigation to better understand the magnitude and mechanisms muscular effects of DFO in aged populations is warranted

Charakterisierung der Munc13-CaM-Wechselwirkung

Munc13-Proteine sind die Hauptakteure beim Priming, einem Vorgang, der an die Plasmamembran angedockte synaptische Vesikel fusionsfähig macht. Im Rahmen dieses essenziellen Schrittes der Ca2+-abhängigen Neurotransmitterfreisetzung spielen Munc13-Proteine weiterhin eine wichtige Rolle bei synaptischen Anpassungsmechanismen wie der präsynaptischen Kurzzeitplastizität. Munc13-1 und ubMunc13-2 enthalten eine konservierte Calmodulin (CaM) Bindungsstelle und die Ca2+-abhängige Wechselwirkung dieser Munc13-Isoformen mit CaM ist als ein molekularer Mechanismus identifiziert worden, der die intrazelluläre Konzentration an Restcalcium (Ca2+i,res) auslesen und als Signal an den präsynaptischen Exocytose-Apparat weitergeben kann. Diese Studie beschreibt die biochemische Charakterisierung der Munc13-CaM Interaktion unter besonderer Berücksichtigung der weiteren Munc13-Isoformen bMunc13-2 und Munc13-3 und liefert Einblicke in die Struktur der Munc13-CaM Komplexe. Mit Hilfe bioinformatischer Analyseverfahren wurde die Anwesenheit potenzieller CaM-Erkennungsmotive auch in den nicht konservierten N-Termini von bMunc13-2 und Munc13-3 vorhergesagt. Von diesen Sequenzmotiven abgeleitete Munc13-Modellpeptide wurden zur Photoaffinitätsmarkierung von CaM eingesetzt und die entstandenen kovalenten Photoaddukte massenspektrometrisch charakterisiert. Die Analyse dieser Peptide-Protein-Interaktionen zeigte, dass alle vier Munc13-Isoformen CaM stöchiometrisch und Ca2+-abhängig binden, und dass diese Bindung bereits durch nur geringfügig erhöhte intrazelluläre Ca2+-Konzentrationen ermöglicht wird. Diese Befunde unterstützen die Schlussfolgerung, dass Konvergenz zu strukturell unterschiedlichen, funktionell jedoch gleichartigen Ca2+/CaM-Bindungsstellen in Munc13-1, ubMunc13-2, bMunc13-2 und Munc13-3 geführt hat, und dass alle Munc13-Isoformen zur präsynaptischen Kurzzeitplastizität beitragen können. Zur strukturellen Charakterisierung der kovalenten Munc13/CaM-Photoaddukte wurde eine innovative analytische Strategie etabliert, die auf Photoaffinitätsmarkierung, isotopenmarkiertem CaM und Massenspektrometrie basiert. So konnte gezeigt werden, dass im gebundenen Zustand die hydrophobe Ankeraminosäure des CaM-Bindungsmotivs von Munc13 zwei Methioninseitenketten in der C-terminalen Domäne von CaM kontaktiert. Diese Kontaktstellen lieferten - zusammen mit durch chemische Quervernetzungsmethoden erhaltene Abstandsbeschränkungen - geeignete Ausgangsbedingungen für ein für molekulares Modelling des Munc13-CaM-Komplexes. Die unter physiologischen Lösungsmittel- und Konzentrationsbedingungen durchführbare Photoaffinitätsmarkierungsanalyse wurde weiterhin eingesetzt, um hochauflösende NMR-Untersuchungen des Munc13/CaM-Komplexes zu komplementieren und die Entdeckung eines neuartigen 1-26 CaM-Bindungsmotiv in Munc13-1 und ubMunc13-2 biochemisch zu unterstützen. Diese strukturellen Informationen über den Munc13/CaM-Komplex eröffnen in Zukunft neue Möglichkeiten für eine detailiertere Erforschung der Rolle von Munc13-Proteinen in den Prozessen des Primings und der präsynaptischen Kurzzeitplastizität

Adult-Onset Still`s Disease - a Clinical Case

Introduction: Adult-onset Still`s disease (AOSD) is a type of systemic onset juvenile idiopathic arthritis. Major criteria include high spiking fevers > 38.5 °C, arthralgia or arthritis, a transient, nonpruritic salmon-colored rash and leukocytosis. Minor criteria may include sore throat, lymphadenopathy, negative rheumatoid factor, abnormal liver function tests, hepatomegaly or splenomegaly. Five criteria are needed for diagnosis with at least two of them being major. The condition may present with a sudden onset and symptoms may disappear and never occur again after treatment initiation, it may also turn into a chronic arthritis or, if affecting internal organs, may lead to severe complications.Materials and Methods: This is a clinical case of a 24-year-old female whose symptoms started during pregnancy and continued postpartum. Therefore, she  was admitted to St. Marina University Hospital, Varna for diagnostic management. Symptoms included fever of 38.6 °C, a rash affecting the upper body and limbs, joint pain and edema in the knees, wrists and ankles with a duration of one month. Antibiotic treatment that was initiated during that period of time did not account to any improvement of the patient`s condition and the fever persisted.Results: A number of clinical examinations and laboratory tests were carried out to exclude sepsis condition or an underlying autoimmune disorder and the patient was diagnosed with AOSD. Treatment with glucocorticoids- Urbason 60 mg, NSAIDs and gastroprotectants was immediately initiated. The rash and joint pain disappeared and an improvement of the patient`s condition was reported.Conclusions: This clinical case is an example of a patient with fever of unknown origin and contributes to the fact that Still`s disease is a diagnosis of exclusion but should be taken into account in the process of diagnosing and managing unexplained fever conditions

Molecular pathogenesis of spontaneous abortions - Whole genome copy number analysis and expression of angiogenic factors.

OBJECTIVE To study two major molecular alterations in spontaneous abortions (SA) with unexplained etiology - fetal genomic anomalies and the endometrial expression of main angiogenic factors VEGFA/VEGFR2 and chemokines SDF-1/CXCR4. MATERIALS AND METHODS Whole genome copy number analysis by arrayCGH or Next Generation Sequencing (NGS) was applied for detection of fetal genomic imbalances. The abortive decidua of SA without fetal aneuploidies was further investigated for expression levels of the abovementioned factors using real time PCR analysis. A total of 30 abortive materials were collected from spontaneous abortions after exclusion of known predisposing factors. RESULTS In 21 of 30 spontaneous abortions (70%), genomic anomalies were discovered by whole genome copy number analysis. Numerical anomalies were detected in 90% of aberrant cases, and in 10% - structural aberrations were revealed. An increased expression for essential factors of angiogenesis was identified in spontaneous abortions' tissues - 3.44 times for VEGFA and 10.29 times for VEGFR2. We found an average of 14 times increase in the expression levels of SDF-1 and 3.21 times for its receptor CXCR4. CONCLUSION We could suggest the occurrence of increased angiogenesis in SA without fetal aneuploidies, compared to the control tissues, which could lead to increased oxidative stress and fetal loss

Dietary Fish Oil Supplement Induces Age-specific Contractile and Proteomic Responses in Muscles of Male Rats

© 2020 The Author(s). Background: Dietary fish oil (DFO) has been identified as a micronutrient supplement with the potential to improve musculoskeletal health in old age. Few data are available for effects of DFO on muscle contractility, despite the significant negative impact of muscle weakness on age-related health outcomes. Accordingly, the effects of a DFO intervention on the contractile function and proteomic profile of adult and aged in an animal model of aging were investigated. Methods: This preliminary study evaluated 14 adult (8 months) and 12 aged (22 months) male, Sprague-Dawley rats consuming a DFO-supplemented diet or a control diet for 8 weeks (7 adult and 6 aged/dietary group). Animal weight, food intake and grip strength were assessed at the start and end of the FO intervention. In situ force and contractile properties were measured in the medial gastrocnemius muscle following the intervention and muscles were processed for 2-D gel electrophoresis and proteomic analysis via liquid chromatography with tandem mass spectrometry, confirmed by immunoblotting. Effects of age, diet and age x diet interaction were evaluated by 2-way ANOVA. Results: A significant (P = 0.022) main effect for DFO to increase (~ 15%) muscle contractile force was observed, without changes in muscle mass. Proteomic analysis revealed a small number of proteins that differed across age and dietary groups at least 2-fold, most of which related to metabolism and oxidative stress. In seven of these proteins (creatine kinase, triosephosphate isomerase, pyruvate kinase, parvalbumin, beta-enolase, NADH dehydrogenase and Parkin7/DJ1), immunoblotting corroborated these findings. Parvalbumin showed only an effect of diet (increased with DFO) (P = 0.003). Significant age x diet interactions were observed in the other proteins, generally demonstrating increased expression in adult and decreased expression aged rats consuming DFO (all P \u3e 0.011). However, correlational analyses revealed no significant associations between contractile parameters and protein abundances. Conclusions: Results of this preliminary study support the hypothesis that DFO can enhance musculoskeletal health in adult and aged muscles, given the observed improvement in contractile function. The fish oil supplement also alters protein expression in an age-specific manner, but the relationship between proteomic and contractile responses remains unclear. Further investigation to better understand the magnitude and mechanisms muscular effects of DFO in aged populations is warranted

Correlation between Cytogenetic Findings and Spermatogenic Failure in Bulgarian Infertile Men

The aim of our study was to determine the type and frequency of chromosomal aberrations and polymorphisms in men with different degrees of spermatogenic failure in comparison to men with normozoospermia, in order to find correlations between cytogenetic findings and the abnormal results of semen analysis. In our study, we performed cytogenetic analysis in 901 infertile men, divided into five groups according to semen analysis—normozoospermia (86), asthenozoospermia (394), oligoasthenozoospermia (182), severe male factor (100), and azoospermia (139). The frequency of polymorphisms was similar in all groups (11–16%, without significant differences). The frequency of numerical and structural aberrations increases with the degree of the spermatogenic failure (3.5% in normozoospermia, 5.6% in asthenozoospermia, 9.8% in oligoasthenozoospermia, 9% in severe male factor, and 13.5% in azoospermia). We found a significantly higher incidence of numerical chromosomal aberrations in severe male factor (7%) and azoospermia (9.3%). Oligoasthenozoospermia occured in 45% of cases with translocation, compared to 20% in the group with a normal karyotype. We revealed that chromosomal translocations are tightly associated with oligoasthenozoospermia, whereas numerical chromosomal aberrations—with severe male factor and azoospermia. The impact of chromosome polymorphisms on male infertility should be studied in greater detail