Investigation of contact phenomena in turning using tools made of low-alloy high-speed steels

U ovom se radu daju rezultati ispitivanja raspodjele temperaturnog polja i trošenja alata tijekom tokarenja čelika C60. Provedena su ispitivanja otpornosti na abrazivno trošenje tokarskih noževa izrađenih od niskolegiranog brzoreznog čelika. Uzorci čelika su toplinski obrađeni i zatim podvrgnuti ionskom nitriranju, oblaganju TiN ili kompleksnoj obradi. Analiziran je utjecaj brzine rezanja na vrijednost osnovnih parametara karakterističnih za pojave u graničnoj površini alat-obradak, t.j. rezni omjer, faktor trenja i dužina zone dodira. Porast vrijednosti kuta nagiba dovodi do porasta vrijednosti faktora trenja. Nadalje, vrijednost faktora trenja se smanjuje kako raste debljina reznog sloja. Ispitivanja trajnosti rezne oštrice potvrđuju da je u definiranju radnih uvjeta alata, najvažnija otpornost na gubitak tvrdoće kod porasta temperature na temperaturama višim i nižim od temperature popuštanja.In this paper, the results of investigations of the temperature field distribution and tool wearing during C60 steel turning are presented. Abrasive wear resistance tests were carried out for cutters made of low-alloy high-speed steel. Steel samples were heat treated, and then were subjected to ion nitriding, TiN coating, or to complex treatment. The influence of cutting speed on the value of basic parameters characterising the phenomena in the tool-workpiece interface i.e., cutting ratio, friction coefficient, and length of contact zone, is analysed. An increase of the rake angle value causes an increase in the value of the friction coefficient. Furthermore, the value of the friction coefficient decreases as the thickness of the cut layer increases. Investigations of the durability of cutting edges confirm that to define the working conditions of the tool, resistance against hardness loss with increasing temperature at temperatures higher and lower than the tempering temperature is the most significant

Sphingolipid Long-Chain Base Hydroxylation Is Important for Growth and Regulation of Sphingolipid Content and Composition in \u3ci\u3eArabidopsis\u3c/i\u3e

Sphingolipids are structural components of endomembranes and function through their metabolites as bioactive regulators of cellular processes such as programmed cell death. A characteristic feature of plant sphingolipids is their high content of trihydroxy long-chain bases (LCBs) that are produced by the LCB C-4 hydroxylase. To determine the functional significance of trihydroxy LCBs in plants, T-DNA double mutants and RNA interference suppression lines were generated for the two Arabidopsis thaliana LCB C-4 hydroxylase genes Sphingoid Base Hydroxylase1 (SBH1) and SBH2. These plants displayed reductions in growth that were dependent on the content of trihydroxy LCBs in sphingolipids. Double sbh1 sbh2 mutants, which completely lacked trihydroxy LCBs, were severely dwarfed, did not progress from vegetative to reproductive growth, and had enhanced expression of programmed cell death associated–genes. Furthermore, the total content of sphingolipids on a dry weight basis increased as the relative amounts of trihydroxy LCBs decreased. In trihydroxy LCB–null mutants, sphingolipid content was ~2.5-fold higher than that in wild-type plants. Increases in sphingolipid content resulted from the accumulation of molecular species with C16 fatty acids rather than with very-long-chain fatty acids, which are more commonly enriched in plant sphingolipids, and were accompanied by decreases in amounts of C16-containing species of chloroplast lipids. Overall, these results indicate that trihydroxy LCB synthesis plays a central role in maintaining growth and mediating the total content and fatty acid composition of sphingolipids in plants

Nanoparticles of copper stimulate angiogenesis at systemic and molecular level

Copper is a key element affecting blood vessel growth and muscle development. However, the ions released from Cu salts are toxic. Given their specific physicochemical properties, nanoparticles of Cu (NanoCu) may have different bioactivity and affect the development of blood vessel and muscles in a different manner than Cu salts. The objective of the study was to evaluate the influence of NanoCu on embryo development and angiogenesis at the systemic and molecular level, in experiments using a chick embryo model. Fertilized chicken eggs were divided into a control group, and groups injected with a placebo, CuSO4 or NanoCu. Embryo development at the whole body level and molecular indices using an embryo chorioallantoic membrane model were measured during embryogenesis. The present study indicated for the first time that NanoCu have pro-angiogenic properties at the systemic level, to a greater degree than CuSO4 salt. The properties of NanoCu were confirmed at the molecular level, demonstrating significant effects on mRNA concentration and on mRNA gene expression of all pro-angiogenic and pro-proliferative genes measured herein

Factors Related to the Level of Depression and Suicidal Behavior Among Men With Diagnosed Depression, Physically Ill Men, and Healthy Men

Depression is the most common psychiatric disorder in people who die by suicide. Awareness of risk factors for suicide in depression is important for clinicians. The study was aimed at establishing models of factors related to the level of depression and suicidal behavior among men from three different groups—in men with depressive disorder, in comparison to men with physical disorder and healthy men. A total of 598 men were included in the study. The following questionnaires were used in research model: test with sociodemographic variables, AUDIT Test, Fagerström Test, Generalized Self-Efficacy Scale (GSES), Inventory for Measuring Coping with Stress (Mini-COPE), Resilience Evaluation Questionnaire (KOP-26), Suicide Behaviors Questionnaire—Revised (SBQ-R) by Osman, and Gotland Male Depression Scale. In men with depression, the positive factors strongly related to the intensity of depression and suicidal behavior were as follows: vocational education, active coping, turning toward religion, social competence for resilience, and bachelor status. The factors negatively related to the intensity of depression and suicidal behavior in this group were as follows: unemployed status, student status, low satisfaction with the financial situation, having children, history of mental disorders in family, alcohol addiction, and seeking instrumental support. In the group of men with physical disorders, the following protection factors were identified: the medium or small city as a place of living, active coping, venting, and personal competence. The following risk factors were identified in this group: psychiatric treatment in the past. In the group of healthy men, the following protective factors were identified: the medium city as a place of living, positive reappraisal, planning abilities, and personal and social competence for resilience. In this group, the following risk factors were identified: vocational and higher education, student status, satisfaction with the financial situation, having more than one children, the occurrence of mental disorders in the family, the occurrence of alcohol abuse in the family, and use of psychoactive substances as a strategy of dealing with stress. The risk factors identified in this study should be included in the clinical assessment of depression and suicidal behavior risk in male patients. There are some protective factors identified, including productive coping and personal and social competencies, which can be developed and should be especially considered and strengthened in mental health promotion programs aimed at men

Promotion of men’s mental health

Introduction: Despite the fact that the knowledge of health differences between males and females is more and more available, it does not always translate into the differentiation of health programmes. Undoubtedly, there is a need for innovative programmes promoting the mental health of men and accounting for male standards. Material and methods: Review of scientific literature concerning mental health promotion, with special regard to recommendation to create programmes of promotion of men’s mental health searched in Pubmed, Scopus and Google Scholar. Results: Health promotion is a process enabling people to increase their control over health and to improve it. Mental health promotion is a rarely discussed branch of health promotion, and its characteristics differ from physical health promotion. Currently, no organised activities are conducted in Poland aiming at the promotion of men’s mental health. Looking at suicide statistics, according to which men take their lives seven times more often than women, it seems essential to design comprehensive activities targeting this specific group. Male-specific determinants of mental health should constitute a reference point for health promoters in the process of designing programmes of mental health promotion. Conclusions: It seems necessary to consider gender factor while designing activities related to mental health promotion. The activities directed to men should be planned according to specific principles. Their implementation may have a positive effect on male participation and involvement in the suggested programme of mental health promotion, and in turn on its efficacy.Introduction: Despite the fact that the knowledge of health differences between males and females is more and more available, it does not always translate into the differentiation of health programmes. Undoubtedly, there is a need for innovative programmes promoting the mental health of men and accounting for male standards. Material and methods: Review of scientific literature concerning mental health promotion, with special regard to recommendation to create programmes of promotion of men’s mental health searched in Pubmed, Scopus and Google Scholar. Results: Health promotion is a process enabling people to increase their control over health and to improve it. Mental health promotion is a rarely discussed branch of health promotion, and its characteristics differ from physical health promotion. Currently, no organised activities are conducted in Poland aiming at the promotion of men’s mental health. Looking at suicide statistics, according to which men take their lives seven times more often than women, it seems essential to design comprehensive activities targeting this specific group. Male-specific determinants of mental health should constitute a reference point for health promoters in the process of designing programmes of mental health promotion. Conclusions: It seems necessary to consider gender factor while designing activities related to mental health promotion. The activities directed to men should be planned according to specific principles. Their implementation may have a positive effect on male participation and involvement in the suggested programme of mental health promotion, and in turn on its efficacy

Methicillin-resistant staphylococcus aureus in Melanesian children with haematogenous osteomyelitis from the Central Highlands of Papua New Guinea

Background: Methicillin-Resistant Staphylococcus aureus (MRSA) has been an important cause of bone infection since the 1940s. Current guidelines recommend targeted antibiotic use for osteomyelitis treatment informed by microbial sensitivity patterns. However, in settings without microbiology facilities, empirical antibiotic use is common. Unrecognized antibiotic resistance potentiates persistence of MRSA with osteomyelitis progression to chronic forms with complications despite antibiotic treatment. Materials and Methods: A prospective observational study was done to identify common etiological agent (s) in bone infection in Melanesian children (that were admitted to the two surgical and one pediatric wards of the SJNM-KUGH in the Simbu province of Papua New Guinea in 2012 and 2017), observe for presence of antimicrobial resistance, and determine effective antibiotic regimes for treatment of bone pediatric osteomyelitis. Seventy pediatric patients presenting from the community with osteomyelitis were recruited, with bone and non-bone specimens sampled, cultured and isolates tested for resistance to common antibiotics. Results: Staphylococcus aureus (S. aureus) was isolated in 67% (47/70) of collected specimens. Of the 47 isolates, there was 91.5% resistance to penicillin, 85.1% resistance to methicillin, 89.4% resistance to oxacillin, 93.6% resistance to ampicillin and 80.9% resistance to ceftriaxone. S. aureus showed 91.5% sensitivity to gentamycin, 93.6% sensitivity to erythromycin, tetracycline and clindamycin, and 95.7% sensitivity to Co-trimoxazole. Conclusion: MRSA was the leading cause of haematogenous osteomyelitis in Melanesian children. S.aureus was isolated mainly from infected long bones of the lower limbs (79%) of children presenting from the community, suggesting a predominantly community-associated MRSA

TEORIA WZMOCNIENIA JEDNOFOLIOWEGO DETEKTORA Z GAZOWYM POWIELANIEM ELEKTRONÓW

Gain prediction theory of single foil Gas Electron Multiplier detector was developed. Gas electron multiplier (GEM) detector with single foil was developed. Soft X-ray spectra with an energy of 5.9 keV emitted by the isotope Fe-55 were measured. On this basis, the dependence of gain and energy resolution from the detector voltage was determined. The simple theory of gain dependence on various detector parameters was developed. Preliminary results of the study confirmed the potential usefulness of the GEM detector as a substitute for the multiwire proportional chamber.Opracowano teorię wzmocnienia jednofoliowego detektora z gazowym powielaniem elektronów. Opracowano detektor z gazowym powielaniem elektronów z pojedynczą folią. Zmierzono widmo miękkiego promieniowania X, o energii 5,9 keV, emitowanego przez izotop Fe-55. Na tej podstawie wyznaczono zależność wzmocnienia i energetycznej zdolności rozdzielczej od napięcia zasilającego detektor. Opracowano prosta teorią zależności wzmocnienia od różnych parametrów detektora. Wstępne rezultaty badań potwierdzają potencjalną przydatność detektora GEM jako substytutu wielodrutowej komory proporcjonalnej

Mechaniczne wspomaganie krążenia w leczeniu ostrego zapalenia mięśnia sercowego powikłanego wstrząsem kardiogennym

Przedstawiono przypadek 27-letniego chorego z ostrym zapaleniem mięśnia sercowego powikłanym wstrząsem kardiogennym. Wdrożono leczenie mechanicznym wspomaganiem krążenia z zastosowaniem wszczepialnego dwukomorowego, zewnętrznego układu wspomagania pracy serca - systemu POLCAS. Ponadto pacjent otrzymywał leki steroidowe, immunoglobuliny i antybiotyki o szerokim spektrum działania. Po uzyskaniu regeneracji uszkodzonego mięśnia sercowego, potwierdzonej badaniem histopatologicznym, system wspomagający odłączono po 31 dobach pracy. Chorego wypisano ze szpitala w stanie ogólnym dobrym po 42 dniach leczenia. Podczas 2-letniej obserwacji stwierdzono pełną poprawę funkcji mięśnia sercowego oraz wydolności krążenia (I grupa wg klasyfikacji NYHA). (Folia Cardiol. 2004; 11: 677-680