Slotted Aloha as a game with partial information

This paper studies distributed choice of retransmission probabilities in slotted ALOHA. Both the cooperative team problem as well as the noncooperative game problem are considered. Unlike some previous work, we assume that mobiles do not know the number of backlogged packets at other nodes. A Markov chain analysis is used to obtain optimal and equilibrium retransmission probabilities and throughput. We then investigate the impact of adding retransmission costs (which may represent the disutility for power consumption) on the equilibrium and show how this pricing can be used to make the equilibrium throughput coincide with the optimal team throughput.     

Financial performance, ISO 9000 standard and safe driving practices effects on accident rate in the U.S. motor carrier industry

The question this research address is if voluntary certification with ISO 9000 standards can reduce the number of accidents large trucks have. Certification might have a positive effect depending upon the actions a company takes as a result of being certified, for instance, a company may change driver training and maintenance and how it carries out corrective action. We identified 40 ISO 9002: 1994 certified U.S. trucking companies and compared their safety performance before and after ISO certification. We also compared them to a group of motor carriers that had similar characteristics but were not certified. The safety performance of the certified carriers was significantly better after certification than before, and it also was significantly better than that of non-certified carriers, findings that we believe can be useful to carriers, shippers and regulators who wish to better understand the value of certification.     

Granulocyte Colony-Stimulating Factor Restored Impaired Spermatogenesis and Fertility in an AML-Chemotherapy Mice Model

Leukemia and treatment of male patients with anticancer therapy (aggressive chemotherapy and/or radiotherapy) may lead to infertility or even permanent male sterility. Their mechanisms of spermatogenesis impairment and the decrease in male fertility are not yet clear. We showed that under acute myeloid leukemia (AML) conditions, alone and in combination with cytarabine (CYT), there was significant damage in the histology of seminiferous tubules, a significant increase in apoptotic cells of the seminiferous tubules, and a reduction in spermatogonial cells (SALL and PLZF) and in meiotic (CREM) and post-meiotic (ACROSIN) cells. In addition, we showed a significant impairment in sperm parameters and fertilization rates and offspring compared to control. Our results showed a significant decrease in the expression of glial cell line-derived neurotrophic factor (GDNF), macrophage colony-stimulating factor (MCSF) and stem cell factor (SCF) under AML conditions, but not under cytarabine treatment compared to control. In addition, our results showed a significant increase in the pro-inflammatory cytokine interleukin-1 (IL-1) alpha in whole testis homogenates in all treatment groups compared to the control. Increase in IL-1 beta level was shown under AML conditions. We identified for the first time the expression of GCSF receptor (GCSFR) in sperm cells. We showed that GCSF injection in combination with AML and cytarabine (AML + CYT + GCSF) extended the survival of mice for a week (from 6.5 weeks to 7.5 weeks) compared to (AML + CYT). Injection of GCSF to all treated groups (post hoc), showed a significant impact on mice testis weight, improved testis histology, decreased apoptosis and increased expression of pre-meiotic, meiotic and post- meiotic markers, improved sperm parameters, fertility capacity and number of offspring compared to the controls (without GCSF). GCSF significantly improved the spermatogonial niche expressed by increased the expression levels of testicular GDNF, SCF and MCSF growth factors in AML-treated mice and (AML + CYT)-treated mice compared to those groups without GCSF. Furthermore, GCSF decreased the expression levels of the pro-inflammatory cytokine IL-12, but increased the expression of IL-10 in the interstitial compartment compared to the relevant groups without GCSF. Our results show for the first time the capacity of post injection of GCSF into AML- and CYT-treated mice to improve the cellular and biomolecular mechanisms that lead to improve/restore spermatogenesis and male fertility. Thus, post injection of GCSF may assist in the development of future therapeutic strategies to preserve/restore male fertility in cancer patients, specifically in AML patients under chemotherapy treatments.     

Cure kinetics of bismaleimides as basis for polyimide-like inks for PolyJet™-3D-printing

Since polyimides are well known for their excellent chemical and thermal stability and outstanding mechanical properties there is increasing interest in developing polyimide-based inks to produce additively manufactured parts with properties superior to those of currently available materials. Usage of bismaleimides (BMI) as precursors allows polyimides to be fabricated via PolyJet™ printing (Stratasys Ltd., Rehovot, Israel). Characterization of the curing kinetics is a central part of process development, as fast curing initiated by UV light is desired. Here, a comprehensive study of thermal and UV curing of BMI oligomers with various molecular weights and chemical structures is presented. Fourier transform infrared spectroscopy serves as a tool for determining the curing degree. Furthermore, an estimation of the activation energy for thermal curing is performed. UV curing of the selected BMIs leads to highly crosslinked, thermoset polymers with excellent chemical resistance and thermal stability which are of great interest for PolyJet™ 3D printing. © 2018 The Authors. Journal of Applied Polymer Science published by Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47244.     

Involvement of Cytokines and Hormones in the Development of Spermatogenesis In Vitro from Spermatogonial Cells of Cyclophosphamide-Treated Immature Mice

Aggressive chemotherapy treatment may lead to male infertility. Prepubertal boys do not produce sperm at this age, however, they have spermatogonial stem cells in their testes. Here, we examined the effect of intraperitoneal injection of cyclophosphamide (CP) on the capacity of immature mice (IM) to develop spermatogenesis in vivo and in vitro [using methylcellulose culture system (MCS)]. Our results show a significant decrease in testicular weight, total number of testicular cells, and the number of Sertoli, peritubular, premeiotic, and meiotic/post-meiotic cells, but an increase in the percentages of damaged seminiferous tubules in CP-treated IM compared to control. The functionality of Sertoli cells was significantly affected. The addition of testosterone to isolated cells from seminiferous tubules of CP-treated IM significantly increased the percentages of premeiotic (CD9-positive cells) and meiotic/post-meiotic cells (ACROSIN-positive cells) developed in MCS compared to control. The addition of FSH did not affect developed cells in MCS compared to control, but in combination with testosterone, it significantly decreased the percentages of CD9-positive cells and ACROSIN-positive cells. The addition of IL-1 did not affect developed cells in MCS compared to control, but in combination with testosterone, it significantly increased the percentages of VASA-positive cells and BOULE-positive cells compared to IL-1 or testosterone. Addition of TNF significantly increased only CD9-positive cells in MCS compared to control, but in combination with testosterone, it significantly decreased ACROSIN-positive cells compared to testosterone. Our results show a significant impairment of spermatogenesis in the testes of CP-treated IM, and that spermatogonial cells from these mice proliferate and differentiate to meiotic/post-meiotic cells under in vitro culture conditions.     

On the inconsistency of the asymmetric-sandwich gurney formula when used to model thin plate propulsion

The asymmetric sandwich Gurney formula is used extensively worldwide during explosive reactive armor and shaped-charge war-head design, in either its original form^(1,2) or its extended form used to model implosion configurations^(3–5). It is therefore very important to realize that calculations may contradict physical observations when the formula is used to calculate the velocity of thin plates having mass which is smaller than half the explosive mass per unit area. This inconsistency between calculation and experimental results is explained as resulting from the failure of the assumption made in deriving all the Gurney formulas that the velocity distribution of the explosive products is a linear function of the expansion coordinate.     

High precision processing of flexible P3HT/PCBM modules with geometric fill factor over 95%

Flexible OPV modules, based on P3HT:PCBM as absorber layer, were manufactured with a power conversion efficiency over 3% and for a total area of 3500 mm² consisting of 14 in series interconnected cells. The modules utilize the excellent mechanical and the outstanding optical properties of sputtered transparent ITO-Metal-ITO (IMI) electrodes deposited on the PET foil on the one hand, and the combination of large area slot-die coating with high resolution ultrafast laser patterning on the other hand. The manufacturing of modules with outstanding performance was found to be reproducible. The right combination of innovative electrodes and smart roll-to-roll compatible processing technologies demonstrates a viable path towards high efficient industrial module technology.     

A Novel Rodent Model of Hypertensive Cerebral Small Vessel Disease with White Matter Hyperintensities and Peripheral Oxidative Stress

Cerebral small vessel disease (CSVD) is the second most common cause of stroke and a major contributor to dementia. Manifestations of CSVD include cerebral microbleeds, intracerebral hemorrhages (ICH), lacunar infarcts, white matter hyperintensities (WMH) and enlarged perivascular spaces. Chronic hypertensive models have been found to reproduce most key features of the disease. Nevertheless, no animal models have been identified to reflect all different aspects of the human disease. Here, we described a novel model for CSVD using salt-sensitive ‘Sabra’ hypertension-prone rats (SBH/y), which display chronic hypertension and enhanced peripheral oxidative stress. SBH/y rats were either administered deoxycorticosteroid acetate (DOCA) (referred to as SBH/y-DOCA rats) or sham-operated and provided with 1% NaCl in drinking water. Rats underwent neurological assessment and behavioral testing, followed by ex vivo MRI and biochemical and histological analyses. SBH/y-DOCA rats show a neurological decline and cognitive impairment and present multiple cerebrovascular pathologies associated with CSVD, such as ICH, lacunes, enlarged perivascular spaces, blood vessel stenosis, BBB permeability and inflammation. Remarkably, SBH/y-DOCA rats show severe white matter pathology as well as WMH, which are rarely reported in commonly used models. Our model may serve as a novel platform for further understanding the mechanisms underlying CSVD and for testing novel therapeutics.     

Microstructure Evolution of SiC/Al2O3/Al-Alloy Composites Produced by Melt Oxidation

Alumina-matrix composites with and without SiC particulates have been produced by directed melt oxidation of a multicomponent Al alloy. In the more general case, the microstructure consists of three interpenetrating phases: the SiC preform, a continuous α-Al₂O₃ matrix, and a network of unoxidized metal. The volume fraction of metal within the oxidation product decreases with increasing processing temperature, and its distribution is less uniform when a preform is present. The preform does not show evidence of degradation by the molten alloy, but the growth front tends to climb up the particles, increasing the oxidation area and enhancing the rate of composite formation. The total porosity of the composite was found to increase with increasing Mg content, processing temperature, and/or SiC particle size. Porosity within the channels is associated primarily with insufficient metal flow to feed the solidification shrinkage. Larger pores are common in the SiC composites and seem to evolve by encroachment of interparticle spaces by the convoluted growth front. Coarse chemical segregation of the heavily alloyed residual metal is pervasive regardless of the presence or characteristics of the preform, but can be significantly refined by increasing the cooling rate of the composite after growth.