The preparation and characterization of chitosan/poly (vinyl alcohol) blended films : mechanical, thermal and surface investigations

In this study, blends of chitosan (CS) and polyvinyl alcohol (PVA) (CS/PVA) having various proportions were prepared and characterized by universal mechanical tester, the differential scanning calorimetry (DSC) and contact angle measurements. Studying the mechanical properties of the films showed that blending improved the tensile strength, which increased with increasing PVA content up to 40% while the elongation% at break of the blends was decreased compared to that of the pure components. The obtained results of DSC suggested that some interaction between chitosan and PVA mostly took place. Static water contact angle measurements showed an improvement in the wettability of the obtained films

Erythrocytes alterations of monosex tilapia (Oreochromis niloticus, Linnaeus, 1758) produced using methyltestosterone

AbstractThe present study aims to investigate the effects of methyltestosterone on monosex farmed tilapia, Oreochromis niloticus by detection of apoptosis, micronucleus and alterations of erythrocytes. Fishes were obtained from four localities (Assiut as a control and Beheira, Alexandria and Kafr EL-Sheikh; three farms from each governorate as farmed monosex produced using methyltestosterone). Blood smears were processed for Hematoxylin and eosin technique. The major alterations recorded in the red blood cells were as swelled cells (Sc), tear drop-like cells (Tr), and sickle cells (Sk). Also, a significant difference (P⩽0.001) between three governorates and Assiut was recorded in the micronucleus test, apoptosis and altered erythrocytes. These alterations are considered as an indication for performance and health of fish in the monosex culture medium indicating the side effects of overdose induction of MT

A Generalized Skew of type IV Logistic Distribution

In this paper, we derive, the probability density function (pdf) and cumulative distribution function (CDF) of the skew type IV generalized logistic distribution GSLD IV . The general statistical properties of the GSLD IV . such as: the moment generating function (mgf), characteristic function (ch.f), Laplace and fourier transformations are obtained in explicit form. Expressions for the nth moment, skewness and kurtosis coefficients are discussed. The mean deviation about the mean and about the median are also obtained. We consider the general case by inclusion of location and scale parameters. The results of Asgharzadeh (2013) are obtained as special cases. Graphically illustration of some results have been represented. Further we present a numerical example to illustrate some results of this paper. Keywords: skew type IV generalized logistic distribution, moment generating function, skewness, kurtosis, mean deviation

Impact of copeptin on diagnosis of acute coronary syndrome

AbstractBackgroundAcute coronary syndrome remains the principal cause of death, so the early diagnosis is of great importance. Cardiac troponin is the preferred biomarker for acute myocardial infarction. Cardiac chest pain immediately increased copeptin secretion. The combination of copeptin and cardiac troponin I is being suggested for early diagnosis of acute coronary syndrome.SubjectIt was done to emphasize the importance of association of copeptin, cardiac troponin I and high sensitive C reactive protein to confirm the diagnosis of acute myocardial infarction or unstable angina pectoris in patients with a cardiac chest pain.MethodThe current study enrolled 22 patients with acute myocardial infarction as group i and 33 patients with unstable angina pectoris as group ii. The third group consisted of 23 apparently healthy persons. Patients and controls were subjecting to laboratory investigations, which include the levels of copeptin, high-sensitivity cardiac troponin high sensitive C reactive protein creatine kinase MB fraction, lipid and I profile.ResultsWe found a significant increase of copeptin in group i when compared to group iii (30.01±12.92) (9.54±3.55), respectively, p value=0.000 and group ii (30.01±12.92) (11.16±4.58) respectively, p value 0.000, but a non-significant difference in group ii when compared to group iii (11.16±4.58) (9.54±3.55) respectively, p value=0.160. Also cardiac troponin I showed a significant increase in group i when compared to group ii (136.73±26.07) (11.18±3.79), p value=0.000, and group iii (136.73±26.07) (9.61±3.70) respectively, p value=0.000, but a non-significant difference between group ii (11.18±3.79), and group iii (9.61±3.70), p value=0.129. There was a positive correlation between copeptin and cardiac troponin I within group i, r=0.718, p value=0.000.ConclusionIn suspected acute coronary syndrome, determination of copeptin and cardiac troponin I provides a remarkable negative predictive value, which aids in early and safe ruling out of myocardial infarction

Designing Lightweight 3D-Printable Bioinspired Structures for Enhanced Compression and Energy Absorption Properties

Recent progress in additive manufacturing, also known as 3D printing, has offered several bene-fits, including high geometrical freedom and the ability to create bioinspired structures with intri-cate details. Mantis shrimp can scrape the shells of prey molluscs with its hammer-shaped stick, while beetles have highly adapted forewings that are lightweight, tough, and strong. This paper introduces a design approach for bioinspired lattice structures by mimicking the internal micro-structures of a beetle’s forewing, a mantis shrimp’s shell, and a mantis shrimp’s dactyl club, with improved mechanical properties. Finite element analysis (FEA) and experimental characterisation of 3D printed polylactic acid (PLA) samples with bioinspired structures were performed to deter-mine their compression and impact properties. The results showed that designing a bioinspired lattice with unit cells parallel to the load direction improved quasi-static compressive perfor-mance, among other lattice structures. The gyroid honeycomb lattice design of the insect forewings and mantis shrimp dactyl clubs outperformed the gyroid honeycomb design of the mantis shrimp shell, with improvements in ultimate mechanical strength, Young’s modulus, and drop weight impact. On the other hand, hybrid designs created by merging two different designs reduced bend-ing deformation to control collapse during drop weight impact. This work holds promise for the development of bioinspired lattices employing designs with improved properties, which can have potential implications for lightweight high-performance applications