Application of Reduced Stiffness of Complex Laminate in Finite Elements for Chair Analysis

This paper presents a numerical procedure for the analysis of complex laminate structures. The procedure is based on the application of reduced stiffness of complex laminate. Introduction of reduced stiffness of composite facilitates both linear and nonlinear numerical integration, i.e. the tangential stiffness matrix is translated in the classical plate theory problem. The formulated numerical procedure was implemented in the program system KOMIPS. Special subroutine REDKRUT that calculates reduced stiffness of the laminate was written, and its application in numerical verification of experiments conducted on chairs was presented in (Nestorovic, 2010). At the end of this work, for 3D stress and strain analysis of veneer composites, recommendations were given for experimental determination of all nine independent material constants E-x, E-y, E-z, v(xy), v(xz), G(xy), G(xz), G(yz), five of which were determined in the previous paper of the author (Nestorovic, 2010)

Prikaz bolesnika s ektopičnom sekrecijom ACTH i znacima Cushingova sindroma

Ectopic ACTH secretion was the first paraneoplastic endocrine syndrome described in the literature. The most common tumors associated with ectopic ACTH production are small-cell lung cancer and atypical carcinoids. High cortisol levels have also been described in patients with adenocarcinoma and large-cell carcinoma of the lung, other carcinoid tumors, thymoma, neural crest tumors, medullary carcinoma of the thyroid, and bronchial adenomas. Patients rarely live long enough for frank Cushing’s syndrome to develop. A 30-year-old male is described, who was admitted to endocrinology ward for clinical features of Cushing’s syndrome. Outpatient examination showed high levels of plasma cortisol on several occasions, without suppression of night dexamethasone test. Laboratory tests performed during his hospital stay showed an increased level of serum cortisol without suppression of night dexamethasone test, increased level of ACTH, and decreased testosterone level, increased 17 OHCS in urine. CT scan of adrenal and pituitary glands, and chest x-ray were normal. The patient was discharged with an appointment made for surgical exploration of the pituitary gland. Transnasal selective partial hypophysectomy was performed, however, excisional biopsy showed no microadenoma while the symptoms persisted postoperatively. The patient received TCT hypophysis in a maximal dose, and elevated ACTH level was found to persist after 37 days of treatment. One year later, the patient was readmitted for persistent cushinoid appearance. After complete investigations for ectopic ACTH secreting tumor, chest x-ray showed an infraclavicular, circular, sharply demarcated inhomogeneous lesion of the left lung, 2x3 cm in size. Three months later, lobectomy was performed and pathohistologic examination pointed to a carcinoid (argentaffinoma). During hospitalization, the symptoms of Cushing’s syndrome regressed. In conclusion, CRH test which usually distinguishes between hyperadrenocorticism associated with ectopic ACTH secretion and hypersecreting adrenal tumors is sometimes misleading because of the large overlap in normal and abnormal responses. In this case, chest or abdominal CT scan or MRI should be performed, because these are the most common sites of ectopic ACTH secreting tumors.Prvi paraneoplastični endokrini sindrom opisan u literaturi bila je ektopična sekrecija ACTH. Najčešći tumori udruženi s ektopičnom sekrecijom ACTH su mikrocelularni karcinom pluća i atipični karcinoidi. Visoke razine kortizola opisane su i u bolesnika s adenokarcinomom i karcinomom velikih stanica pluća, karcinoidima, timomom, tumorima neuralnog grebena, medularnim karcinomom štitnjače i bronhalnim adenomom. Bolesnici rijetko žive dovoljno dugo da razviju manifestan Cushingov sindrom. Opisan je slučaj 30-godišnjeg muškarca koji je primljen na odjel s kliničkim znacima Cushingova sindroma. Ambulantno ispitivanje pokazalo je u više navrata visoke razine kortizola koji se nije snižavao u kratkom deksametazonskom testu. Tijekom boravka u bolnici je uz već navedeno uočena visoka razina ACTH, sniženi testosteron i povišen 17 OHCS u mokraći. CT nadbubrežnih žlijezda i Rtg snimka prsnog koša bili su uredni. Bolesnik je otpušten uz dogovor za kiruršku eksploraciju hipofize, te je učinjena transnazalna djelomična hipofizektomija. Ekscizijska biopsija nije pokazala znakove tumora, a klinički znaci Cushingova sindroma ustrajali su nakon operacije. Bolesnik je podvrgnut radioterapiji hipofize u maksimalnoj dozi, međutim, vrijednosti ACTH su još uvijek bile povišene. Nakon godinu dana bolesnik je ponovno primljen na odjel zbog ustrajnih znakova Cushingova sindroma. Nakon potpune obrade u smislu traženja ektopične sekrecije ACTH, snimka prsnoga koša pokazala je infraklavikularno oštro ograničenu, nehomogenu sjenu u plućima, veličine 2x3 cm. Tri mjeseca kasnije učinjena je lobektomija, a patohistološki nalaz je ukazao na karcinoid (argentafinom). Tijekom hospitalizacije simptomi Cushingova sindroma su se povukli. U zaključku, CRH test koji obično razlikuje hiperadrenokorticizam udružen s ektopičnom sekrecijom ACTH i hipersekreciju iz adrenalnih tumora, ponekad je neprikladan zbog značajnog preklapanja u normalnom i abnormalnom odgovoru. U tom slučaju, nužan je detaljan pregled prsnoga koša i trbuha, budući da su to najčešća sijela tumora koji ektopično izlučuju ACTH

D-mannitol for medium temperature thermal energy storage

D-mannitol is a sugar alcohol with a melting temperature of approximately 167 °C. It has been identified as a phase change material for storing heat at a temperature range of about 150-180 °C. The outcome of the published research on its applicability for this purpose is inconsistent and sometimes contradictory. We identified that there is a need for further study on the material to overcome such uncertainty. Thus we conducted a series of thermal measurements to quantify its properties and suitability for a phase change thermal storage. Our differential scanning calorimetric measurements showed that the material has a melting temperature of 167 °C and fusion heat of 297 kJ/kg. However, our accelerated thermal cycling test revealed that this value decreases logarithmically to 249 and 240 kJ/kg after 100 and 200 cycles respectively. The material shows a significant level of sub-cooling in DSC measurement with a solidification temperature of approximately 110-120 °C which can render the material unsuitable for thermal storage purposes. However, our secondary measurement with a large quantity of D-mannitol shows that such level of sub-cooling is unlikely to occur in a macro-scale sample. We built and tested a thermal storage system containing 3.8 kg of D-mannitol to investigate its performance in larger quantities and evaluate the heat transfer properties of the heat exchanger mechanism in the storage system. We show that the material releases significant heat when it is cooled down to 150 °C which means implies the occurrence of solidification at a temperature above 150 °C

Rapid large-scale evolutionary divergence in morphology and performance associated with exploitation of a different dietary resource

Although rapid adaptive changes in morphology on ecological time scales are now well documented in natural populations, the effects of such changes on whole-organism performance capacity and the consequences on ecological dynamics at the population level are often unclear. Here we show how lizards have rapidly evolved differences in head morphology, bite strength, and digestive tract structure after experimental introduction into a novel environment. Despite the short time scale (≈36 years) since this introduction, these changes in morphology and performance parallel those typically documented among species and even families of lizards in both the type and extent of their specialization. Moreover, these changes have occurred side-by-side with dramatic changes in population density and social structure, providing a compelling example of how the invasion of a novel habitat can evolutionarily drive multiple aspects of the phenotype