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Like females of many commercially important fishes, Liza ramada fail to complete ovarian development and do not undergo final maturation (FOM), ovulation or spawning when reared in captivity. The aim of the present work was to investigate the histological and physiological changes during the reproductive cycle of Liza ramada reared in freshwater fish ponds and during induction of spawning in saline water. In the present study, the levels of total thyroxine (T4), triiodothyronine (T3) and cortisol in the plasma of Liza ramada in a complete reproductive cycle were measured in correlation with the seasonal histological changes in gonads. During the reproductive cycle of females, serum triiodothyronine (T3), thyroxine (T4) and cortisol decreased during ovarian early-vitellogenesis and increased during mid-vitellogenesis to reach a peak for both T4 and cortisol. Then, these hormones declined to low levels during late-vitellogenesis. At the prespawning stage, all mentioned hormones re-increased to high levels and finally declined during induction of spawning. There was a decrease in serum levels of thyroid and cortisol hormones coincided with an increase in testicular activity of the fish. T3 and T4 increased during testis ripening to reach a peak during spawning, while cortisol reached a peak during ripe stage and decreased to low levels during spawning. In conclusion, the seasonal changes in thyroid hormones and cortisol concomitant with gonadal maturation and spawning of Liza ramada support role for these hormones in reproduction and stress response of this fish. [ABSTRACT FROM AUTHOR]

In the current paper, the modal characterisation of aramid–carbon fiber hybrid composites (ACFRP) and ACFRP reinforced with silica nanoparticles (nACFRP) is investigated through the analytical-experimental transfer function method. The modal properties, such as resonant frequencies and modal loss factors, are measured by vibrating cantilever beam specimens with an impact hammer, while the vibratory response is detected through an acceleration transducer. The procedure for the identification of analytical-experimental transfer functions is carried out using a genetic algorithm by minimising the difference between the measured response from tests and the calculated response, which is a function of the modal parameters. The analytical transfer functions provide a substructuring process to identify modes, as a function of damped natural frequencies and loss factors of a complex structure, and it is insensitive to experimental noise as well as the modal coupling effect. The validation of the proposed method is verified with 10 degrees of freedom mass-spring dashpot model. The effectiveness of the proposed method is demonstrated by investigating the static and dynamic behaviour of the ACFRP and nACFRP specimens. Results indicate that the inclusion of nanosilica particles increase the stiffness of the ACFRP, although the damping response of the reinforced specimens is moderately improved. [ABSTRACT FROM AUTHOR]

An efficient identification method for modal testing of viscoelastic composite materials is demonstrated in this paper, through the analytical–experimental transfer function method. The procedure for the identification of analytical–experimental transfer functions is carried out using a genetic algorithm (GA) by minimizing the difference between the measured response from tests and the calculated response, which is a function of the modal parameters. The analytical transfer functions provide a sub-structuring process to identify modes, as a function of damped natural frequencies and loss factors of a complex structure and it is insensitive to experimental noise as well as the modal coupling effect. The proposed method is verified with the calculation of the elastic modulus and modal properties of a cantilever steel beam with the FEM and compared with the identification results of the proposed algorithm. The effectiveness of the proposed method is demonstrated by investigating the static and dynamic behavior of epoxy cantilever beam specimens reinforced with silica nanoparticles. Analytical–experimental transfer functions accurately identified the viscoelastic and dynamic response of the studied specimens, while the results indicated that the inclusion of nanosilica particles increased the stiffness of the epoxy network and the damping response of the reinforced specimens is improved. [ABSTRACT FROM AUTHOR]

The mechanical and modal properties of epoxy resin reinforced with different content of carboxyl-terminated butadiene acrylonitrile copolymer (CTBN) rubber were investigated in this paper with an analytical-experimental identification method. Mechanical tensile tests were conducted for concentrations between 0 and 25wt% of CTBN rubber. The dynamic responses of the epoxy/CTBN rubber composites were measured by vibrating cantilever beam specimens with an impact force through a modal hammer, while the vibratory response was detected through an acceleration transducer. The analytical-experimental transfer function method is utilized for the deduction and therefore comparison of the elasticity modulus of the epoxy/rubber composites. The procedure for the identification of analytical-experimental transfer functions was carried out using a genetic algorithm (GA) by minimizing the difference between the measured response from tests and the calculated response, which is a function of the modal parameters. Both tensile and modal tests have shown, while it was evident from the results that the CTBN composites could absorb greater amounts of strain energy. The modal test results indicate that CTBN rubber particles can improve the damping capacity of the epoxy-based composites. However, it was observed that the stiffness of the epoxy/CTBN rubber composites was dramatically reduced. [ABSTRACT FROM AUTHOR]

Uniaxial compression tests were conducted in this study in order to investigate the compressive properties of the unmodified and nanomodified epoxy with silica nanoparticles. An instrumented nanoindentation technique was also used to investigate its applicability for measuring mechanical properties for such nanocomposite systems. Additionally, the fracture toughness of the unmodified and nanomodified epoxy was measured with single-edge-notch bending tests. The Young’s modulus was found to significantly improve with addition of silica nanoparticles and increase with increasing filler content when measured with both compression and nanoindentation tests. The modulus obtained from the nanoindentation testing was 4–8% higher than the one obtained from the compression tests. As expected, the addition of silica nanoparticles had a significant impact on the fracture toughness and fracture energy and increased with increasing filler content, while observation of the fracture surfaces using SEM suggested that the nanoparticles affected the fracture behavior of such epoxy systems. Implementation of an analytical model in the current nanomodified epoxy network as compared with the experimental fracture energy results showed that the 15% matrix void growth, from debonded nanoparticles, as well as the matrix shear banding are the governing mechanisms of energy absorption. [ABSTRACT FROM AUTHOR]

Highlights: [•] Development of a method for simulating objects by 3D scanning. [•] The curves used are 3rd degree polynomial form. [•] Algorithm usage for point reduction of the scanning blades at measuring machine CMM. [•] The test time is reduced drastically. [•] The maximum deviation of the polynomial algorithm is of the order of 10–20μm. [Copyright &y& Elsevier]

The efficiency of epoxy reinforcements provided by multiwall carbon nanotubes (MWCNTs) and fumed silica particles as well as hybrids of these two materials was assessed. Also, comparisons between the mechanical properties were performed as obtained from macroscale and nanoscale experimental methods in the form of uniaxial tensile tests and instrumented nanoindentation testing. The results showed that the material stiffness and hardness is higher for nanocomposites having 1%wt MWCNTs while the lowest values were obtained for the hybrid nanocomposites. The nanoindentation technique proved an effective method of measuring the mechanical properties providing that a suitable calibration method is followed. [ABSTRACT FROM PUBLISHER]

Nanoindentation testing is used in this paper in order to investigate the mechanical properties of specimens with varying weight percentage of fumed silica using a low-viscosity liquid epoxy resin as a matrix. Controversial results are reported in the literature regarding the elastic modulus of fumed silica epoxy nanocomposites using conventional tensile tests, thereby there is much scope in investigating comparatively such systems in a nanometer scale. The results show that the hardness and modulus of the nanocomposites steadily decrease with increasing fumed silica content which was attributed to the severe tendency for cluster formation as studied by optical microscope and scanning electron microscope analysis. The variations in elastic modulus as measured using the nanoindentation testing technique revealed small differences from the tensile test data. A material-depending calibration procedure has been used by utilising the epoxy elastic modulus as measured by the tensile tests in order to account for the indentation inherent uncertainties in the tip shape calibration. The results demonstrate that the nanoindentation testing technique is an effective mechanical testing method for epoxy nanocomposites when an appropriate calibration procedure is followed. [ABSTRACT FROM AUTHOR]

Examines the synthesis and physical characteristics of hydrophobic forms of solvatochromic N,N-dialkyl-p-nitroanilines. Reaction of p-halonitrobenzene to di-n-alkylamine; Purification of oil phase products; Adoption of Gauche conformation; Solvatochromic properties of the compounds.

In this paper, the marginal distributions of concomitants of k-record values based on Sarmanov family of bivariate distributions are obtained, as an extension of several recent papers. Besides, we derive the joint distribution of concomitants of k-record values for this family. Furthermore, some new and useful properties of information measures, namely, the extropy, Shannon entropy, inaccuracy measure, cumulative entropy, cumulative residual entropy, and cumulative residual Fisher information are studied. Finally, we offered various examples accompanied by numerical investigations that backed up the theoretical findings. [ABSTRACT FROM AUTHOR]

Presents the case of a 34-year-old woman with amniotic fluid (AF) leakage after mid-trimester amniocentesis, at 15 weeks' gestation for increased nuchal translucency. Major risk factors of AF leakage; Explanation for the total loss of AF.

Background: Pseudomonas aeruginosa plays a major influence on poultry outbreaks. Several factors may contribute to its pathogenicity. Aims: This study aimed to investigate the prevalence of P. aeruginosa infection among layer chickens with phenotypic and genotypic characterization of the isolates. Methods: Samples (n=160) were collected from respiratory distressed layer chickens according to the lesion and bacteriologically examined for isolation of P. aeruginosa from Sharkia province, Egypt. The antimicrobial sensitivity was performed against 18 antimicrobial agents. A qualitative assessment of biofilm production was performed using the Tube method. The isolates were genetically examined for confirmation, detection of quorum sensing genes, virulence genes, and biofilm production genes by conventional PCR. Results: P. aeruginosa was isolated from 25% of the samples. Moreover, 95% of the isolates were extensively drug-resistant (XDR) with multiple antibiotic resistance indices (MARI) of 0.67 to 0.83. A total of 38 isolates were able to produce biofilm with different degrees. PCR of 16S rRNA (P. aeruginosa) and oprL genes confirmed the existence of P. aeruginosa isolates. For quorum sensing genes, lasI and lasR were successfully amplified at 100% and 89.5%, respectively. For virulence genes, toxA and exoU were amplified by a percentage of 78.9%, while the higBA gene was in 100% of the isolates. pprA and pprB genes were amplified at 100% and 89.5%, respectively. For biofilm genes, pslA, fliC, and pelA were amplified in 100%, 84.2%, and 10.5%, respectively. Conclusion: A strong correlation between quorum sensing genes, biofilm genes, and virulence genes was detected. Further, biofilm production increases the resistance of the isolates to antimicrobial agents. [ABSTRACT FROM AUTHOR]

Sarmanov family of bivariate distributions, which was suggested by Sarmanov (Mathematical models in hydrology symposium, 1974) as a new mathematical model of hydrological processes, is considered one of the most flexible and efficient extended families of the traditional FGM family. Despite its manifest advantages, it was never investigated in the literature. In this paper, we revisit this family by revealing several new prominent statistical properties. The distribution theory of concomitants of order statistics from this family is investigated. Besides, some aspects of information measures, namely the Shannon entropy, inaccuracy measure, and Fisher information number, are theoretically and numerically studied. Two bivariate real-world data sets have been analyzed for illustrative purposes, and the performance is quite satisfactory. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents some new results on the position analysis in polynomial form of the class-three Assur group. The aim of this position analysis is to determine all possible configurations of the Assur group, for a given position of its external joints. Five new kinds of the class-three Assur group with two or three prismatic joints are investigated. The analysis leads to a non-linear system of equations. Using a successive elimination procedure, a final polynomial equation in one unknown is obtained. The real solutions of this polynomial equation correspond to assembly modes of the Assur group. Finally, five numerical applications of the proposed methods are presented. [Copyright &y& Elsevier]

A procedure for the automatic generation of the robot programming used in manufacturing operations is introduced in the present paper. The off-line programming system developed here includes graphical simulation of the robot and its workcell, kinematic model of the robot, motion planning and creation of the NC code for manufacturing process. The proposed system is applied in a robot with five revolute joints for manufacturing operations and in a robot with six revolute joints for welding operations. [ABSTRACT FROM AUTHOR]

This paper presents the solution in polynomial form to the position analysis of the Assur group of class 4 (tetrad) with four links, one prismatic and five revolute joints. The aim of this position analysis is to determine all possible configurations of the Assur group, for a given position of its external joints. The analysis leads to a non-linear system of three equations with three unknown parameters. Using a successive elimination procedure, a final polynomial equation of sixth order in one unknown is obtained. The roots of the polynomial equation lead to, at most, six different configurations of the Assur group in the complex field. Two kinds of the Assur group of class 4, the first with one external and the second with one internal prismatic joint, are investigated. In both cases, the numerical examples lead to two real solutions, which correspond to assembly modes of the Assur group. An application of the proposed method is also given for planar mechanism including such groups. [Copyright &y& Elsevier]

This paper presents the position analysis in analytical form of the Assur group of class 3 and order 3 with four links and six revolute/prismatic joints (triad). The aim of this position analysis is to determine all possible configurations of the Assur group, for a given position of its external joints. Four kinds of the Assur group of class 3, with one, two and three prismatic joints are investigated. The analysis leads to a nonlinear system of three equations with three unknown parameters. Using a successive elimination procedure, a final polynomial equation in one unknown is obtained. The real solutions of the polynomial equation correspond to assembly modes of the Assur group. Three numerical applications of the proposed methods are presented. Finally, a numerical application for position analysis of a planar mechanism with eight links including a triad with three external prismatic joints is also given. [Copyright &y& Elsevier]

Objective: To determine preoperative method that predicts nature of ovarian tumors. Methods: Fifty patients with complex pelvic masses assessed preoperatively with two-dimensional ultrasound (2DUS), two-dimensional power Doppler (2DPD), three-dimensional ultrasound (3DUS), three-dimensional power Doppler (3DPD), color Doppler. Results: All patients underwent exploration, 19 (38%) had benign tumors, 31 (62%) had ovarian cancer. 2DUS identified 29 cases suspicious for malignancy giving sensitivity, specificity, PPV and accuracy of 80%, 78%, 86%, and 80%. 2DUS with 2DPD identified 28 suspicious cases giving sensitivity, specificity, PPV and accuracy of 80%, 84%, 89%, and 82%. 3DUS identified 31 suspicious cases including 28 cancers giving sensitivity, specificity, PPV and accuracy of 90%, 84%, 90%, and 88%. 3DUS with 3DPD, identified 34 suspicious cases including all 31 cancers giving sensitivity, specificity, PPV and accuracy of 100%, 84%, 91%, and 94%. Color Doppler RI of 0.48 identified 28 cases of 31 cancers giving sensitivity of 90%. Conclusion: Evaluation by 3DUS with 3DPD improves diagnostic accuracy of ovarian tumors. [ABSTRACT FROM AUTHOR]