Stimulatory effect of follicle-stimulating hormone on basal and luteinizing hormone-stimulated testosterone secretions by the fetal rat testis in vitro

The in vitro effect of FSH on testosterone secretion by the fetal rat testis was studied. Testes were cultured in the presence or absence of either commercial human (h) FSH (Metrodine; 200 mIU/ml) or recombinant hFSH (200 mIU/ml) for 3 days and with 100 ng/ml ovine LH during the last 4 h of culture. To avoid a stimulatory effect by the 0.4% LH that contaminates Metrodine, the cultures were performed in the presence of a monoclonal anti-hLH beta antibody and with a concentration of Metrodine that had no short term stimulatory effect on testosterone production by the fetal testes in vitro. Metrodine treatment had a positive long term effect on both basal and LH-stimulated testosterone secretion by fetal testes explanted on days 18.5, 20.5, and 22.5 postconception, which was abolished by the addition of a monoclonal anti-hFSH beta antibody. LH-free recombinant FSH also augmented basal and LH-stimulated testosterone secretion of testes explanted on days 13.5, 14.5, and 18.5 postconception. The positive effect of recombinant hFSH appeared during the second day of treatment with day 14.5 and 18.5 testes and on the third day of treatment with day 13.5 testes. As it is widely accepted that FSH receptors are exclusively localized on Sertoli cells, these results suggest that on or before day 15.5 of fetal life, 1) Sertoli cells are able to respond to FSH, 2) Sertoli cells can produce factors that are able to act on Leydig cell function, and 3) Leydig cells are sensitive to FSH-induced Sertoli cell factors. In conclusion, this study points out a potential paracrine control of fetal Leydig cell function and/or differentiation by fetal Sertoli cells as soon as fetal Leydig cells differentiate.     

Sorption of propylene and propane in polyurethane membranes containing silver nanoparticles

The preparation of a facilitated transport membrane of polyurethane (PU) containing silver nanoparticles is reported. The propylene and propane sorption was investigated aiming at the selective separation from C3s mixtures. The silver particles were photogenerated in situ into the polyurethane matrix using UV light radiation and silver triflate (AgCF₃SO₃) as precursor. The morphological properties of these membranes (PUAg) reveled great dispersion of silver particles, which size was smaller than 110 nm. The propylene solubility in PUAg resulted more than four times superior to the one for the pure PU membrane, revealing the high affinity between silver and propylene. Flory–Huggins theory was more accurate to describe the propylene sorption behavior in PUAg than Henry's model. The ideal solubility selectivity of PUAg membrane resulted 24.4, indicating that there is a good potential for an industrial application aiming at the separation of propylene/propane. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42916.     

Dual-layer hollow fibers for gas separation processes produced by quadruple spinning

A novel quadruple spinneret to produce dual-layer hollow fiber membranes by simultaneous spinning of two polymer solutions, using the dual precipitation bath technique is proposed. Hollow fibers aimed at gas separation processes were prepared in extrusion system specifically designed and built for this purpose. A polyurethane polymer was selected as the selective layer (outer-layer), while polyethersulfone was defined as the support (inner-layer). Activated carbon powder was added into the PU solution for further improvement of the transport properties. The hollow fibers showed good adhesion between the polymer layers and a defect-free selective layer. Representative results include a CO₂/N₂ selectivity of 43.     

Dual‐Layer Hollow Fibers for Sulfur Removal from Fuels

Emission of sulfur compounds to the atmosphere is universally recognized as one key target to be reduced. For membrane pervaporation which is considered as a potential purification process of fuels, dual‐layer polyurethane (PU)/polyethersulfone hollow‐fiber membranes were prepared. A novel fabrication technique is proposed using a quadruple spinneret to produce the fiber with such morphology by simultaneous spinning of two polymer solutions in the presence of two corresponding precipitation media. Activated carbon was added into the PU solution to improve the transport properties of the selective layer. Resulting hollow‐fiber membranes showed very good adhesion between the selective layer and its support, in addition to an effective removal of a sulfur compound such as 2‐methyl thiophene from a typical model fuel, an indication of good prospects for both the fabrication technique and for sulfur removal by pervaporation of fuels.     

Cement production technology improvement compared to factor 4 objectives

In this study, the effects of potential technological improvements in cement industry are compared to global goals of sustainability such as those from the Intergovernmental Panel Group for Climate Change. In other words, does the current and standard technological knowledge in the cement and concrete industry make it possible to achieve the “factor 4” concept? This concept aims at reducing the CO₂ emissions in developed countries in 2050 by a factor of four from their 1990 levels, after they have first been reduced by a factor of 2 by 2020. The present study shows that it seems technically possible to design concretes to meet “factor 2” objectives whatever the evolution of cement production, but a technological turnaround is needed to reach factor 4 objectives. This technological shift will require not only changes in concrete raw materials and mix designs, but also new building techniques, using less materials for the same final structure.     

Structural change of water with solutes and temperature up to 100 degrees C in aqueous solutions as revealed by attenuated total reflectance infrared spectroscopy

The attenuated total reflectance infrared (ATR-IR) spectra of several aqueous solutions have been measured by using a newly developed heatable rod-type ATR cell. The OH stretching bands showed systematic change with increasing solute concentrations and these changes can be explained by four different OH components based on curve-fitting results. NaCl solutions show longer H-bond distance character, while carbonate solutions present shorter ones. The Na2CO3 1 M solution conserves this shorter H-bond nature up to 100 degrees C. On the other hand, the loose nature of NaCl solutions becomes less pronounced at higher temperatures because of the dissociation of pure water clusters. These in situ observations of water structures are generally in agreement with the expected nature of fluids within the earth.     

Unexpected Interacting Effects of Physical (Radiation) and Chemical (Bisphenol A) Treatments on Male Reproductive Functions in Mice

For decades, numerous chemical pollutants have been described to interfere with endogenous hormone metabolism/signaling altering reproductive functions. Among these endocrine disrupting substances, Bisphenol A (BPA), a widely used compound, is known to negatively impact germ and somatic cells in the testis. Physical agents, such as ionizing radiation, were also described to perturb spermatogenesis. Despite the fact that we are constantly exposed to numerous environmental chemical and physical compounds, very few studies explore the impact of combined exposure to chemical and physical pollutants on reproductive health. The aim of this study was to describe the impact of fetal co-exposure to BPA and IR on testicular function in mice. We exposed pregnant mice to 10 µM BPA (corresponding to 0.5 mg/kg/day) in drinking water from 10.5 dpc until birth, and we irradiated mice with 0.2 Gy (γ-ray, RAD) at 12.5 days post-conception. Co-exposure to BPA and γ-ray induces DNA damage in fetal germ cells in an additive manner, leading to a long-lasting decrease in germ cell abundance. We also observed significant alteration of adult steroidogenesis by RAD exposure independently of the BPA exposure. This is illustrated by the downregulation of steroidogenic genes and the decrease of the number of adult Leydig cells. As a consequence, courtship behavior is modified, and male ultrasonic vocalizations associated with courtship decreased. In conclusion, this study provides evidence for the importance of broadening the concept of endocrine disruptors to include physical agents, leading to a reevaluation of risk management and regulatory decisions.     

Ionically crosslinked poly(acrylic acid) membranes. I. Wet technique

A study has been made of the ionic crosslinking of poly(acrylic acid) membranes for possible applications in dialysis and reverse osmosis. The technique consists of casting a film of poly(acrylic acid) neutralized with sodium hydroxide, followed by immersion in appropriate metal salts (aluminium, zinc, and chromium salts). A qualitative rate model has been developed to guide this synthesis. Since both metal cations and protons in solution compete for the carboxylic acid sites, acid–base properties of the metal and polycarboxylic acid appear to be important for successful membrane formation. The use of a nonsolvent for the polymer in the crosslinking solution was tested and found to give improved membranes under some conditions. The nonsolvents tested were methanol, acetone, benzene, and dimethylformamide, dimethylformamide being the most successful. Crosslinking agents such as the Zn²⁺ and Cr³⁺ salts were tried but were not as successful as the Al³⁺ salts. A series of membranes was synthesized in aluminium/dimethylformamide crosslinking baths under various conditions in order to determine suitable procedures for preparation of membranes.     

A potential biodegradable lubricant from castor biodiesel esters

Worldwide, 12 million tonnes per year of lubricants are disposed of in the environment through leakages, exhausted gas, incorrect disposal, water–oil emulsions and so on. Some are resistant to biodegradation, representing an environmental threat. One solution to modify this situation is the replacement of mineral oils by biodegradable synthetic lubricants. Esters, whose chemical structures are similar to natural triglycerides, are excellent substitutes for mineral oils. Castor oil contains around 90% ricinoleic acid, and as a result, castor oil has a higher viscosity and a lower viscosity index, compared with other vegetable oils. This work was based on the production of biodegradable lubricant base fluids from castor biodiesel esters, using various chemical catalysts to yield products with interesting properties, such as high viscosity index and good oxidation stability, compared with mineral oils. This route to lubricants is safer, more economical and more efficient. Copyright © 2012 John Wiley & Sons, Ltd.     

Estrogen effects on fetal and neonatal testicular development

In recent years, evidences have accumulated that exposure to environmental components with estrogenic activity causes reproductive disorders in human populations. Studies conducted over the past 50 years have clearly shown a continual decline in semen quality accompanied by an increase in male reproductive disorders during this period in industrial countries. As healthy gametes are a prerequisite for healthy children, such disorders are a significant problem not only for the current society, but also for future generations. These male reproductive disorders have been attributed to xenobiotics, and particularly to xenoestrogens, which have steadily increased in diversity and concentration in the environment and food. Epidemiological, clinical, and experimental studies have suggested that excessive exposure to estrogens and xenoestrogens during fetal and neonatal development may induce testicular developmental disorders, leading to alterations in the adult male fertility. Recently, we have clearly demonstrated that fetal and neonatal testes are very sensitive to estrogens, as the inactivation of estrogen receptor alpha increases steroidogenesis and the inactivation of estrogen receptor beta enhances development of the germ cell lineage in the male.