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Background and Objective: Methotrexate (MTX) is a chemotherapy drug that has destructive effects on body tissues, including the male reproductive system. Since coenzyme Q10 is an antioxidant that can reduce its destructive effects to some extent, this study was conducted to investigate the effects of the simultaneous use of methotrexate and coenzyme Q10 on testis tissue structure and sperm parameters in male mice. Methods: In this experimental study, 24 male NMRI mice were divided into four groups of six: the control group received 0.2 ml of distilled water intraperitoneally, the MTX group received 20 mg/kg methotrexate once a week intraperitoneally, the CoEnQ10 group received coenzyme Q10 orally at a dose of 200 mg/kg three times a week, and the MTX+CoEnQ10 group, in addition to receiving methotrexate 20 mg/kg intraperitoneally once a week, also received coenzyme Q10 orally at a dose of 200 mg/kg three times a week. All groups were treated for five weeks. After sacrificing the animals, epididymal cauda and testis tissue were sampled and analyzed respectively in order to check sperm parameters and histomorphometry changes and the process of spermatogenesis. Findings: After treatment with MTX, viability, motility, tubule differentiation index, spermatic index, sperm repopulation index, mean seminiferous tubules diameter, seminiferous tubules lumen diameter, and germinal epithelium height decreased significantly compared to the control group (p<0.05). Furthermore, the treatment with MTX significantly led to DNA damage, an increase in the mean diameter of the testicular capsule and the percentage of tubular degeneration, and an increase in the number of abnormal sperms compared to the control group (p<0.05). Simultaneous use of coenzyme Q10 with MTX resulted in significant improvement of the mentioned parameters. Conclusion: The results of the present study showed that MTX has a negative effect on the metabolic activity of sperm, integrity of membrane and DNA, causing a decrease in sperm parameters and changes in testicular tissue and the process of spermatogenesis. Significant improvement of coenzyme Q10 and MTX co-administration enhances the protective effect of coenzyme Q10. [ABSTRACT FROM AUTHOR]

The objective of this work is to provide experimental validation of the graph theory approach for predicting the thermal history of additively manufactured parts. The graph theory approach for thermal modeling in additive manufacturing (AM) was recently published in these transactions. In the present paper, the graph theory approach is validated with in situ infrared thermography data in the context of the laser powder bed fusion (LPBF) additive manufacturing process. We realize the foregoing objective through the following four tasks. First, two kinds of test shapes, namely, a cylinder and cone, are made in two separate builds on a production-type LPBF machine (Renishaw AM250); the material used for these tests is stainless steel (SAE 316L). The intent of both builds is to influence the thermal history of the part by controlling the cooling time between the melting of successive layers, called the interlayer cooling time (ILCT). Second, layer-wise thermal images of the top surface of the part are acquired using an in situ a priori calibrated infrared camera. Third, the thermal imaging data obtained during the two builds is used to validate the graph theory-predicted surface temperature trends. Fourth, the surface temperature trends predicted using graph theory are compared with results from finite element (FE) analysis. The results substantiate the computational advantages of the graph theory approach over finite element analysis. As an example, for the cylinder-shaped test part, the graph theory approach predicts the surface temperature trends to within 10% mean absolute percentage error (MAPE) and approximately 16 K root mean squared error (RMSE) relative to the surface temperature trends measured by the thermal camera. Furthermore, the graph theory-based temperature predictions are made in less than 65 min, which is substantially faster than the actual build time of 171 min. In comparison, for an identical level of resolution and prediction error, the finite element approach requires 175 min. [ABSTRACT FROM AUTHOR]

The goal of this work is to predict the effect of part geometry and process parameters on the instantaneous spatiotemporal distribution of temperature, also called the thermal field or temperature history, in metal parts as they are being built layer-by-layer using additive manufacturing (AM) processes. In pursuit of this goal, the objective of this work is to develop and verify a graph theory-based approach for predicting the temperature distribution in metal AM parts. This objective is consequential to overcome the current poor process consistency and part quality in AM. One of the main reasons for poor part quality in metal AM processes is ascribed to the nature of temperature distribution in the part. For instance, steep thermal gradients created in the part during printing leads to defects, such as warping and thermal stress-induced cracking. Existing nonproprietary approaches to predict the temperature distribution in AM parts predominantly use mesh-based finite element analyses that are computationally tortuous--the simulation of a few layers typically requires several hours, if not days. Hence, to alleviate these challenges in metal AM processes, there is a need for efficient computational models to predict the temperature distribution, and thereby guide part design and selection of process parameters instead of expensive empirical testing. Compared with finite element analyses techniques, the proposed mesh-free graph theory-based approach facilitates prediction of the temperature distribution within a few minutes on a desktop computer. To explore these assertions, we conducted the following two studies: (1) comparing the heat diffusion trends predicted using the graph theory approach with finite element analysis, and analytical heat transfer calculations based on Green's functions for an elementary cuboid geometry which is subjected to an impulse heat input in a certain part of its volume and (2) simulating the laser powder bed fusion metal AM of three-part geometries with (a) Goldak's moving heat source finite element method, (b) the proposed graph theory approach, and (c) further comparing the thermal trends predicted from the last two approaches with a commercial solution. From the first study, we report that the thermal trends approximated by the graph theory approach are found to be accurate within 5% of the Green's functions-based analytical solution (in terms of the symmetric mean absolute percentage error). Results from the second study show that the thermal trends predicted for the AM parts using graph theory approach agree with finite element analyses, and the computational time for predicting the temperature distribution was significantly reduced with graph theory. For instance, for one of the AM part geometries studied, the temperature trends were predicted in less than 18 min within 10% error using the graph theory approach compared with over 180 min with finite element analyses. Although this paper is restricted to theoretical development and verification of the graph theory approach, our forthcoming research will focus on experimental validation through in-process thermal measurements. [ABSTRACT FROM AUTHOR]

Herein, the tetradentate N,N′-dipyridoxyl(4-methyl-1,2-phenylenediamine) [=H2L] Schiff base and its Cu(II) salen complex [Cu(L)] are newly synthesized and characterized by IR, NMR and mass spectroscopies together with the elemental analysis. In addition, their geometrical parameters, assignment of their IR bands and NMR chemical shifts of the Schiff base are calculated using density functional theory (DFT) methods. Natural bond orbital analyses were performed at the same computational level, too. In the optimized geometry of the free ligand the aromatic rings are not in the same plane. The structure of the complex is more planar, where the dianionic Schiff-base acts as a tetradentate ligand in the N,N,O-,O-manner. Two phenolic oxygen atoms and two azomethine nitrogen atoms occupy four coordination positions of the square complex. The DFT-calculated results are in good agreement with the experimental values, confirming the suitability of the optimized geometries for the Schiff base and its Cu(II) complex. [ABSTRACT FROM AUTHOR]

By a new method of modeling, the DLVO energy interaction between rough nanoparticles and rough surfaces is investigated at various conditions. Rippled sphere model and surface element integration method are used. For calculation of energy interaction, the spherical coordinates are used and by increasing the radius ratio of two particles, the pseudo flat surfaces are generated. With increasing the radius ratio of two particles to 50, the large particle behaves as flat surface in front of small particle. Roughness, size of particles, temperature, zeta potential, capacity, and concentration of ions, which influence the stability of nanocolloidal solutions, are considered by the new method. Spherical coordinates enable to model the rough nanoparticles and rough surfaces so that no simplifying assumptions are needed, which was very difficult and time-consuming in Cartesian coordinate system. New method could predict the effect of different parameters on the stability of nanocolloidal systems precisely, easily, and at short times in comparison to Cartesian coordinate. [ABSTRACT FROM PUBLISHER]

The periodic trimming of the long hairs growing at the distal end of the tail -switch trimming- is humane alternative of tail docking. The purpose of this study was to determine the influence of switch trimming on somatic cell count (SCC), California mastitis test (CMT) and udder cleanliness of lactating cows in a freestall dairy farm. In the present study, 219 healthy, pregnant Holstein cows were enrolled. All cows were randomly allocated to either trimmed (T) (n=107) or control (C) groups (n=112) prior to entering the calving pen. The long hair in the tail switch of the cows enrolled in group T was removed completely by a hair clipper machine, while the tail hair of the animals enrolled in group C remained intact. After two months, all studied cows were evaluated for udder cleanliness and health. Udder cleanliness scores (UCS) were significantly associated with switch trimming of the tail (P=0.0129). Both trimmed and control cows showed significant difference in UCS of 2 and 3 (P=0.05), though the difference in other UCS was not significant. No significant difference (P≤0.41) in SCC between groups was identified. Comparing the CMT scores of front, rear, or all udder quarters showed that the frequency of a CMT score of 0 in group T was significantly higher than in group C (P≤0.05). Reversely, the frequencies of Trace and 2 scores of CMT for rear and all udder quarters in the control group were significantly higher than the group T (P<0.05). The results of this study show that switch trimming may be suggested to improve cleanliness and udder health of dairy cows in free-stall housing systems. [ABSTRACT FROM AUTHOR]