Multi-scale analysis of the effect of loading conditions on monotonic and fatigue behavior of a glass fiber reinforced polyphenylene sulfide (PPS) composite

In this paper, two kinds of PPS/GF composite samples (PPS-0°, PPS-90°) were prepared with two different fiber main orientations related to the injection direction. A wide range of their properties were discussed. Using DMTA analysis, it was shown that the PPS/GF composite under study obeyed the time-temperature equivalence principle. Moreover, Perez model was verified and gave a good estimation of the viscoelastic properties of the PPS/GF. Monotonic and fatigue behaviors and fatigue life of PPS/GF were investigated. Fiber's orientation, applied amplitude and loading frequency effects were emphasized. Self-heating effect on fatigue strength was also analyzed. SEM fracture surface observations allowed analyzing, at the local scale, the main deformation mechanisms occurring during mechanical loading. No evident damage development was observed for both monotonic and fatigue loading. PPS matrix plasticity appeared to be the predominant deformation mechanism until a semi-ductile or semi-brittle final failure depending on the loading conditions and local microstructure

The effects of poly L-lactic acid nanofiber scaffold on mouse spermatogonial stem cell culture

Introduction: A 3D-nanofiber scaffold acts in a similar way to the extracellular matrix (ECM)/basement membrane that enhances the proliferation and self-renewal of stem cells. The goal of the present study was to investigate the effects of a poly L-lactic acid (PLLA) nanofiber scaffold on frozen-thawed neonate mouse spermatogonial stem cells (SSCs) and testis tissues. Methods: The isolated spermatogonial cells were divided into six culture groups: (1) fresh spermatogonial cells, (2) fresh spermatogonial cells seeded onto PLLA, (3) frozen-thawed spermatogonial cells, (4) frozen-thawed spermatogonial cells seeded onto PLLA, (5) spermatogonial cells obtained from frozen-thawed testis tissue, and (6) spermatogonial cells obtained from frozen-thawed testis tissue seeded onto PLLA. Spermatogonial cells and testis fragments were cryopreserved and cultured for 3 weeks. Cluster assay was performed during the culture. The presence of spermatogonial cells in the culture was determined by a reverse transcriptase polymerase chain reaction for spermatogonial markers (Oct4, GFRα-1, PLZF, Mvh(VASA), Itgα6, and Itgβ1), as well as the ultrastructural study of cell clusters and SSCs transplantation to a recipient azoospermic mouse. The significance of the data was analyzed using the repeated measures and analysis of variance. Results: The findings indicated that the spermatogonial cells seeded on PLLA significantly increased in vitro spermatogonial cell cluster formations in comparison with the control groups (culture of SSCs not seeded on PLLA) (P�0.001). The viability rate for the frozen cells after thawing was 63.00 ± 3.56. This number decreased significantly (40.00 ± 0.82) in spermatogonial cells obtained from the frozen-thawed testis tissue. Both groups, however, showed in vitro cluster formation. Although the expression of spermatogonial markers was maintained after 3 weeks of culture, there was a significant downregulation for some spermatogonial genes in the experimental groups compared with those of the control groups. Furthermore, transplantation assay and transmission electron microscopy studies suggested the presence of SSCs among the cultured cells. Conclusion: Although PLLA can increase the in vitro cluster formation of neonate fresh and frozen-thawed spermatogonial cells, it may also cause them to differentiate during cultivation. The study therefore has implications for SSCs proliferation and germ cell differentiation in vitro. © 2013 Eslahi et al

Experimental study of PLA thermal behavior during fused filament fabrication

Fused filament fabrication (FFF) is an additive manufacturing technique that is used to produce prototypes and a gradually more important processing route to obtain final products. Due to the layer-by-layer deposition mechanism involved, bonding between adjacent layers is controlled by the thermal energy of the material being printed, which strongly depends on the temperature development of the filaments during the deposition sequence. This study reports experimental measurements of filament temperature during deposition. These temperature profiles were compared to the predictions made by a previously developed model. The two sets of data showed good agreement, particularly concerning the occurrence of reheating peaks when new filaments are deposited onto previously deposited ones. The developed experimental technique is shown to demonstrate its sensitivity to changing operating conditions, namely platform temperature and deposition velocity. The data generated can be valuable to predict more accurately the bond quality achieved in FFF parts

Psychometric Properties of the Persian Adaptation of Mini-Cog Test in Iranian Older Adults

The aim of this study was to assess the psychometric properties of the Mini-Cog in Iranian older adults. It was a cross-sectional study; 50 older people with dementia and 50 without dementia who matched for age, gender, and education entered the study. The diagnostic and statistical manual of mental disorders criteria for dementia were used as gold standard. A battery of scales included the abbreviated mental test score (AMTS), the Geriatric Depression Scale, and the Mini-Cog was performed. Validity and reliability of the Mini-Cog determined using the Pearson product-moment correlation coefficient (Pearson�s r), Cronbach�s alpha, and Receiver Operating Characteristic (ROC) curve analysis. The Persian version of Mini-Cog showed a good inter-rater reliability (K = 0.76, p <.01) and a positive concurrent validity (r = 0.39, p <.01) with the AMTS. The sensitivity and specificity were 88 and 62.8, respectively, using the original cutoff point of 2. The findings showed that the Persian version of Mini-Cog have an acceptable sensitivity, specificity, and substantial overall agreement with the AMTS. © 2017, © The Author(s) 2017

Psychometric Properties of the Persian Adaptation of Mini-Cog Test in Iranian Older Adults

The aim of this study was to assess the psychometric properties of the Mini-Cog in Iranian older adults. It was a cross-sectional study; 50 older people with dementia and 50 without dementia who matched for age, gender, and education entered the study. The diagnostic and statistical manual of mental disorders criteria for dementia were used as gold standard. A battery of scales included the abbreviated mental test score (AMTS), the Geriatric Depression Scale, and the Mini-Cog was performed. Validity and reliability of the Mini-Cog determined using the Pearson product-moment correlation coefficient (Pearson�s r), Cronbach�s alpha, and Receiver Operating Characteristic (ROC) curve analysis. The Persian version of Mini-Cog showed a good inter-rater reliability (K = 0.76, p <.01) and a positive concurrent validity (r = 0.39, p <.01) with the AMTS. The sensitivity and specificity were 88 and 62.8, respectively, using the original cutoff point of 2. The findings showed that the Persian version of Mini-Cog have an acceptable sensitivity, specificity, and substantial overall agreement with the AMTS. © 2017, © The Author(s) 2017

Protective effects of manganese on the testis structure and sperm parameters of formalin-treated mice

Background: Formaldehyde, as a ubiquitous environmental pollutant, is extensively used in industrial and hospitals settings. The aim of this study was to investigate the protective role of manganese on testis structure and sperm parameters in adult mice exposed to formaldehyde (FA). Methods: After dose optimizing for FA and manganese chloride, twenty adult male NMRI mice were selected and randomly divided into four groups: (i) control, (ii) sham, (iii) FA-exposed, and (iv) FA and manganese chloride exposed. The FA-exposed groups received 10 mg/ kg FA daily for 14 days, and 5 mg/kg manganese chloride was just injected intraperitoneally on 2nd week. Mice were sacrificed, and spermatozoa were collected from the caudal of the right epididymis and analyzed for count, motility, morphology and viability. The other testicular tissues were weighed and prepared for histological examination upon removal. Seminiferous tubules, lumen diameters and epithelium thickness were also measured. Findings: The findings revealed that FA significantly reduced the testicular weight, sperm count, motility, viability and normal morphology compared with control group (P � 0.05). In addition, seminiferous tubules atrophied and seminiferous epithelial cells disintegrated in the FA group in comparison with the control group (P � 0.05). However, manganese improved the testicular structure and sperm parameters in FA-treated mice testes (P � 0.05). Conclusion: According to the results, manganese has protective effects on mice epididymal sperm parameters and testis structure treated with FA

Effects of Kerack used in addict iranian people on fertility of adult mice

Background: Infertility is one of the most serious social problems. Illicit drug use can be an important cause of male factor infertility. Kerack which its use is rising up in Iran refers to a high purity street-level heroin (heroin Kerack). Heroin Kerack used in Iran is an opioid and has harmful effects on body organs. The aim of this study is to investigate the effects of Kerack used in Iran on fertility adult mice. Methods: In this study, 25 male mice were divided into five groups (control, sham and three experimental). Experimental groups of Kerack-dependent mice (received ascend-ing dose of Kerack for seven days) were divided into three categories, experimental I, II and III. Experimental I was given Kerack at a dose of 5 mg/kg, experimental II 35 mg/kg and experimental III 70 mg/kg, intraperitoneally twice a day for a period of 35 days. The sham group received normal saline and lemon juice (2.6 μl/ml) whilst the control group just received water and food. Mice were then scarified and sperm removed from cauda epididymis were analyzed for sperm count, motility, morphology (normal/abnormal) and viability. Testes were also removed, weighed and processed for light microscopic studies. Results: The results showed that fertility were significantly decreased in addicted mice compared with control groups (P�0.05). Epididymal sperm parameters and thickness of seminiferous epithelium were significantly decreased in experimental groups (dose-dependent) compared with sham and control groups (P�0.05). Gonadosomatic index was significantly reduced with high dose Kerack injected (70 mg/kg) in comparison with control testes (P�0.05). Conclusion: This study has shown the deleterious effects of Kerack used in addicted Iranian people on fertility for the first time. This effect is especially on epididymal sperm parameters in adult mice

Tsga10 expression correlates with sperm profiles in the adult formalin-exposed mice

Testis-specific gene antigen10 (Tsga10), as a cytoskeletal protein in the sperm tail, impacts the sperm motility. This study investigates the correlation between sperm profile alterations and Tsga10 gene expression in adult mice exposed to formaldehyde (FA) and then treated with antioxidant effect of manganese (Mn2+). In this regard, we examined 35 NMRI adult male mice (6�8 weeks age) in 4 groups of control, sham, FA-exposed and FA+Mn2+. The mice in FA+Mn2+ group were exposed to FA (10 mg kg�1 twice a day) for 2 weeks and treated with daily Mn2+ administration (5 mg kg�1) in the second week prior to sacrificing the mice for testis dissection. The right testis was dissected in each group and subjected to RNA extraction and cDNA syntheses for gene expression analysis by real-time PCR. The findings revealed that FA decreased sperm parameters and Tsga10 expression (52.6 ± 24.37). However, the injected powerful manganese antioxidant improved sperm profile through overexpression of Tsga10 (121.6 ± 27.13) under FA-induced stressful condition which proves the correlation between sperm profile and Tsga10 expression (P � 0.05). This study also shows that Tsga10 expression protects sperm dysfunction in FA+Mn2+ group and resulting in better preservation of spermatozoa and improvement of male fertility. © 2016 Blackwell Verlag Gmb

The effects of poly L-lactic acid nanofiber scaffold on mouse spermatogonial stem cell culture

Neda Eslahi,1,2,* Mahmoud Reza Hadjighassem,1,3 Mohammad Taghi Joghataei,1,2 Tooba Mirzapour,4 Mehrdad Bakhtiyari,1,2 Malak Shakeri,5 Vahid Pirhajati,1,2 Peymaneh Shirinbayan,6,* Morteza Koruji1,21Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran; 2Department of Anatomical Sciences, School of Medicine, Iran University of Medical Sciences, Tehran, Iran; 3Department of Neurosciences, School of Advanced Medical Technologies, Tehran University of Medical Sciences, Tehran, Iran; 4Department of Biology, Faculty of Science, University of Mohaghegh Ardabili, Ardabil, Iran; 5Department of Animal Science, Agricultural Campus, University of Tehran, Tehran, Iran; 6Pediatric Neuro-Rehabilitation Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran*These authors contributed equally to this articleIntroduction: A 3D-nanofiber scaffold acts in a similar way to the extracellular matrix (ECM)/basement membrane that enhances the proliferation and self-renewal of stem cells. The goal of the present study was to investigate the effects of a poly L-lactic acid (PLLA) nanofiber scaffold on frozen-thawed neonate mouse spermatogonial stem cells (SSCs) and testis tissues.Methods: The isolated spermatogonial cells were divided into six culture groups: (1) fresh spermatogonial cells, (2) fresh spermatogonial cells seeded onto PLLA, (3) frozen-thawed spermatogonial cells, (4) frozen-thawed spermatogonial cells seeded onto PLLA, (5) spermatogonial cells obtained from frozen-thawed testis tissue, and (6) spermatogonial cells obtained from frozen-thawed testis tissue seeded onto PLLA. Spermatogonial cells and testis fragments were cryopreserved and cultured for 3 weeks. Cluster assay was performed during the culture. The presence of spermatogonial cells in the culture was determined by a reverse transcriptase polymerase chain reaction for spermatogonial markers (Oct4, GFR&alpha;-1, PLZF, Mvh(VASA), Itg&alpha;6, and Itg&beta;1), as well as the ultrastructural study of cell clusters and SSCs transplantation to a recipient azoospermic mouse. The significance of the data was analyzed using the repeated measures and analysis of variance.Results: The findings indicated that the spermatogonial cells seeded on PLLA significantly increased in vitro spermatogonial cell cluster formations in comparison with the control groups (culture of SSCs not seeded on PLLA) (P&le;0.001). The viability rate for the frozen cells after thawing was 63.00% &plusmn; 3.56%. This number decreased significantly (40.00% &plusmn; 0.82%) in spermatogonial cells obtained from the frozen-thawed testis tissue. Both groups, however, showed in vitro cluster formation. Although the expression of spermatogonial markers was maintained after 3 weeks of culture, there was a significant downregulation for some spermatogonial genes in the experimental groups compared with those of the control groups. Furthermore, transplantation assay and transmission electron microscopy studies suggested the presence of SSCs among the cultured cells.Conclusion: Although PLLA can increase the in vitro cluster formation of neonate fresh and frozen-thawed spermatogonial cells, it may also cause them to differentiate during cultivation. The study therefore has implications for SSCs proliferation and germ cell differentiation in vitro.Keywords: PLLA nanofibers, tissue cryopreservation, testi