22 research outputs found

    Phase analysis of NiTi shape memory wires and computer simulations of the superelastic effect

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    Shape memory alloys belong to the group of intelligent materials due to their exceptional properties related to reversible martensitic transformation. They show both superelasticity and shape memory effects. The modelling of the superelastic phenomena occurring in NiTi alloys is important due to its application in the further development of materials for dedicated applications. A computer simulation of static tensile test was carried out using the finite element method for NiTi wire and obtained results were compared with experimental curve. For the determination of phase composition at ambient temperature and courses of phase transitions during cooling and heating the X-ray powder diffraction and differential scanning calorimetry methods were used. X-ray diffraction phase analysis exhibited that the studied wire at room temperature has B2 — parent phase structure. Additionally, differential scanning calorimetry measurements showed that the phase transformations during cooling and heating occur in a temperature range of about –20 to +30 C

    Pituitary tumours — a large retrospective single-centre study of over 2300 cases. Experience of a tertiary reference centre

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    Introduction: Pituitary adenomas (PAs), also known as a pituitary neuroendocrine tumours (PitNET), are usually benign tumours of the anterior lobe of the pituitary gland and account for the third most common intracranial neoplasm. The most common type of pituitary adenoma is lactotroph adenoma, in which dopamine agonists are the first-line treatment. Nevertheless, in selected cases surgery or even radiotherapy may be required. In the current study, we aimed to analyse all patients who underwent surgery due to intrasellar mass in order to evaluate frequency of particular pituitary tumours, clinical diagnosis, and pathology findings. Material and methods: We retrospectively analysed all cases of patients consecutively operated due to intrasellar mass between 1st January 2010 and 31st December 2018 at the Department of Neurosurgery, Military Institute of Medicine in Warsaw, Poland. Results: Our database included 2348 cases: 1390 women (59.2%) and 958 men (40.8%). The mean age for women was 48.4 years (SD ± 15.72; median 49) and for men 50.9 years (SD ± 14.94; median 53). In our cohort we found: 869 gonadotroph and null cell adenomas, 751 somatotroph and mammosomatotroph adenomas, 386 corticotroph adenomas, 71 plurihormonal adenomas, 59 craniopharyngiomas, 44 lactotroph adenomas, 18 purely thyrotroph adenomas, and other rare cases of pituitary tumours including one pituitary carcinoma metastasising to the liver (corticotroph origin). Conclusions: We provide a comprehensive analysis of both clinical and pathological findings of the largest cohort of patients operated on for pituitary adenomas in one tertiary reference centre. To the best of our knowledge, this is the largest up-to-date published analysis in our country.

    Ockham’s Razor for a Retinal Lesion and Acromegaly and Breaking the Vicious Circle

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    Acromegaly due to ectopic secretion of growth hormone-releasing hormone (GHRH) is rare. Treatment consists of surgical removal of the primary tumor, cytostatic therapy, “cold” or radioactive somatostatin analogue treatment, and medical therapy for acromegaly, if needed. A 53 year-old female had an ocular lesion noted on a routine optician visit, originally considered to be an ocular melanoma. She had a bronchial carcinoid successfully removed 22 years previously. She had acromegalic features with an enlarged pituitary gland on magnetic resonance imaging and, additionally, metastatic lesions in her bones, liver, and thyroid gland. Elevated GHRH levels (>250× upper limit of normal) suggested a metastatic lung neuroendocrine tumor secreting GHRH. Cold and radioactive somatostatin analogue therapy reduced both GHRH and insulin-like growth factor 1 (IGF-1) levels, but normalization of the biochemical markers of acromegaly was only achieved after pegvisomant was introduced. Complete control of IGF-1 was achieved, and this may have hindered the growth of the metastatic lesions as well, as the patient remains well 13 years after the diagnosis of metastatic disease and 35 years after the original lung operation. A gradual rise in prolactin levels over last 4 years was noted, which is likely due to the prolonged effect of GHRH on prolactin-secreting cells. The diagnosis of this case applied the law of parsimony from the Ockham’s razor principle. We consider that breaking the vicious circle of IGF-1 feeding the metastatic tumor was key for the long-term outcome of this case

    The Suppressor of AAC2 Lethality SAL1 Modulates Sensitivity of Heterologously Expressed Artemia ADP/ATP Carrier to Bongkrekate in Yeast

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    The ADP/ATP carrier protein (AAC) expressed in Artemia franciscana is refractory to bongkrekate. We generated two strains of Saccharomyces cerevisiae where AAC1 and AAC3 were inactivated and the AAC2 isoform was replaced with Artemia AAC containing a hemagglutinin tag (ArAAC-HA). In one of the strains the suppressor of ΔAAC2 lethality, SAL1, was also inactivated but a plasmid coding for yeast AAC2 was included, because the ArAACΔsal1Δ strain was lethal. In both strains ArAAC-HA was expressed and correctly localized to the mitochondria. Peptide sequencing of ArAAC expressed in Artemia and that expressed in the modified yeasts revealed identical amino acid sequences. The isolated mitochondria from both modified strains developed 85% of the membrane potential attained by mitochondria of control strains, and addition of ADP yielded bongkrekate-sensitive depolarizations implying acquired sensitivity of ArAAC-mediated adenine nucleotide exchange to this poison, independent from SAL1. However, growth of ArAAC-expressing yeasts in glycerol-containing media was arrested by bongkrekate only in the presence of SAL1. We conclude that the mitochondrial environment of yeasts relying on respiratory growth conferred sensitivity of ArAAC to bongkrekate in a SAL1-dependent manner. © 2013 Wysocka-Kapcinska et al

    Improving academic teaching of tourism and recreation students

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    Cel badań. W artykule zaprezentowano problem kształcenia kadr w zakresie turystyki na poziomie studiów wyższych na wrocławskiej Akademii Wychowania Fizycznego. Celem artykułu jest wskazanie obszarów i kierunków działań zmierzających do udoskonalenia kształcenia na kierunku turystyka i rekreacja tak, aby w możliwie największym stopniu zaspokajało ono potrzeby i spełniało oczekiwania studentów. Materiał i metody. Aby zrealizować główny cel badawczy, zastosowano metodę sondażu diagnostycznego (technika ankiety audytoryjnej) oraz metodę analizy i krytyki piśmiennictwa. W badaniach ankietowych wzięli udział studenci III roku I stopnia (97 osób) oraz II roku II stopnia (67 osób), kończący studia na Akademii Wychowania Fizycznego we Wrocławiu na kierunku turystyka i rekreacja. Wyniki i wnioski. Studenci dokonali oceny kształcenia na badanym kierunku m.in. w zakresie programu nauczania, organizacji studiów oraz infrastruktury uczelni. W efekcie autorki zidentyfikowały dwa obszary oraz sześć kierunków działań, których celem będzie udoskonalenie oferty kształcenia na analizowanym kierunku.Background. The paper presents the issue of training professionals in tourism at the higher education level at the University School of Physical Education in Wrocław. The aim of the article is to identify areas and directions of activities to improve teaching in Tourism and Recreation in order to fulfil the needs and meet the expectations of students to the greatest possible degree. Material and methods. The method of literature analysis and critique, as well as the method of diagnostic survey (auditorium questionnaire technique) were used to achieve the main purpose of the research. Students of the third year of the first degree studies (97 persons) and of the second year of the second degree studies (67 persons), who would soon graduate from the University School of Physical Education in Wrocław, Tourism and Recreation specialisation, took part in the survey. Results and conclusions. The students evaluated the education process in the fields of, among others, the curriculum, study organization, and the University infrastructure. As a result, the authors identified two areas and six directions for improvement aimed at improving the educational offer within the analysed specialisation

    The influence of autologous and heterologous extract of antimicrobial peptides on leukocytes isolated during titanium implant insertion in rabbit and ovine model

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    This study evaluated the in vitro leukocyte response to titanium implants in the presence of autologous or heterologous antimicrobial peptides extracts. Antimicrobial peptides (AMPs) appeared to be a new approach both against microorganisms and for regulation of inflammatory and repair processes. To evaluate their potential usefulness in regenerative medicine, we prepared different extracts of neutrophil-derived AMPs from rabbit, ovine or porcine blood which contained AMPs of different compositions, mainly defensins, cathelicidins and fragments thereof. Then, we assessed in vitro the influence of different AMPs extracts on the neutrophils and monocyte-derived macrophages (MDM) activity. For this purpose, these cells were obtained from experimental animals, rabbits, or sheep submitted to insertion of a titanium implant into the tibial defect. The cultured cells stimulation was autologous or heterologous, dependently on the AMPs extract origin and the experimental animal species. The neutrophil activity was assessed on the basis of the enzymes release from azurophilic and secondary granules and the free radicals generation. The MDM functional assessment was based on the NO and superoxide generation and arginase activity. Additionally, morphological changes were evaluated in the cell cultures. Our results indicated that the origin of AMPs extract is crucial for its activity. The autologous extracts stimulated anti-inflammatory responses, whereas the heterologous extracts displayed pro-inflammatory effect on neutrophils and macrophages. These results might be considered during the introduction of new preparations in regenerative medicine
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