Sintering and final properties of kaolinite-magnesite tapes for the manufacture of cordierite-mullite ceramics

The present work aims at studying the effect of the sintering temperature and magnesite addition on the structure and final properties of silicate ceramics tapes. A kaolinitic clay from Algeria was selected and mixed with different magnesite contents (≤12 mass%). Tape casting process was used to produce the green tapes in an aqueous system with optimized amount of surfactants. The green tapes were fired from 1000°C to 1200°C using a dwelling time of 30 minutes. The effect of the dwelling time was investigated for a firing temperature of 1200°C namely: 30 minutes, 1 hour 30 minutes and 3 hours for samples with 6 and 12 mass% of magnesite. Regarding firing conditions, crystalline phases, thermal conductivity, porosity, and flexural strength were analyzed. The results showed that increasing the sintering temperature to 1200°C tended to significantly decrease the total porosity of samples, which led to the improvement of the stress to rupture values. Specimens with 6 and 12 mass% sintered during 3 hours exhibited highest stress to rupture values (≈117 MPa) and lowest thermal conductivity (<0.2 W.m⁻¹.K⁻¹) and moderate open porosity (27%). The as-obtained ceramics appeared promising for further utilization in refractory industry, thanks to the presence of both cordierite and mullite phases.     

Acid Sphingomyelinase Deficiency: A Clinical and Immunological Perspective

Acid sphingomyelinase deficiency (ASMD) is a lysosomal storage disease caused by deficient activity of acid sphingomyelinase (ASM) enzyme, leading to the accumulation of varying degrees of sphingomyelin. Lipid storage leads to foam cell infiltration in tissues, and clinical features including hepatosplenomegaly, pulmonary insufficiency and in some cases central nervous system involvement. ASM enzyme replacement therapy is currently in clinical trial being the first treatment addressing the underlying pathology of the disease. Therefore, presently, it is critical to better comprehend ASMD to improve its diagnose and monitoring. Lung disease, including recurrent pulmonary infections, are common in ASMD patients. Along with lung disease, several immune system alterations have been described both in patients and in ASMD animal models, thus highlighting the role of ASM enzyme in the immune system. In this review, we summarized the pivotal roles of ASM in several immune system cells namely on macrophages, Natural Killer (NK) cells, NKT cells, B cells and T cells. In addition, an overview of diagnose, monitoring and treatment of ASMD is provided highlighting the new enzyme replacement therapy available.     

Crosstalk between Sodium–Glucose Cotransporter Inhibitors and Sodium–Hydrogen Exchanger 1 and 3 in Cardiometabolic Diseases

Abnormality in glucose homeostasis due to hyperglycemia or insulin resistance is the hallmark of type 2 diabetes mellitus (T2DM). These metabolic abnormalities in T2DM lead to cellular dysfunction and the development of diabetic cardiomyopathy leading to heart failure. New antihyperglycemic agents including glucagon-like peptide-1 receptor agonists and the sodium–glucose cotransporter-2 inhibitors (SGLT2i) have been shown to attenuate endothelial dysfunction at the cellular level. In addition, they improved cardiovascular safety by exhibiting cardioprotective effects. The mechanism by which these drugs exert their cardioprotective effects is unknown, although recent studies have shown that cardiovascular homeostasis occurs through the interplay of the sodium–hydrogen exchangers (NHE), specifically NHE1 and NHE3, with SGLT2i. Another theoretical explanation for the cardioprotective effects of SGLT2i is through natriuresis by the kidney. This theory highlights the possible involvement of renal NHE transporters in the management of heart failure. This review outlines the possible mechanisms responsible for causing diabetic cardiomyopathy and discusses the interaction between NHE and SGLT2i in cardiovascular diseases.     

Cryostructuration of polymer systems. XXIV. Poly(vinyl alcohol) cryogels filled with particles of a strong anion exchanger: Properties of the composite materials and potential applications

A composite material produced from a poly(vinyl alcohol) cryogel with entrapped particles of the strong anion‐exchange resin Amberlite is presented. The properties of the composite material depended strongly on whether the resin was used in OH^? form or Cl^? form. The ion‐exchange filler in OH^? form caused both a significant reinforcement of the composite material and an increase in the gel fusion temperature. These effects were thought to be associated with the additional ionic bonding between the continuous and disperse phases. Beads 200–600 μm in size were prepared from the composite material and used in expanded‐bed ion‐exchange chromatography for the capture of the negatively charged solutes benzoate and lactate from the suspension of negatively charged cells. The plausibility of the approach has been demonstrated on model systems composed of yeast cells and benzoate and with a real fermentation broth produced after lactic acid fermentation. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 529–538, 2005     

Knee pain amongst the poor and affluent in Pakistan

We present a case of adenoid cystic carcinoma of the trachea. The tumor could not be resected due to extensive progression but it was effectively treated endoscopically with a Nd-YAG Laser followed by 70 Gy of conventional radiotherapy. Histologically-confirmed complete remission was achieved, and the patient has lived for nearly 9 years without recurrence of disease.     

Biodegradable microparticulates of beta-estradiol: preparation and in vitro characterization

Beta-estradiol has been recommended for the long-term therapy of osteoporosis and its oral formulations are subjected to intensive first pass metabolism. The present investigation was aimed at preparing and characterizing biodegradable microparticles of beta-estradiol with polymers such as PLA, PLGA 85/15, PLGA 75/25, and their mixtures. The microparticles were prepared by solvent evaporation method using methylene chloride as a solvent and polyvinyl alcohol as a surfactant. The drug-polymer ratios were 1:3, 1:5, and 1:7. The prepared microparticles (twelve formulations) were tested for encapsulation efficiency and in vitro drug release in 50% methyl alcohol/phosphate buffer pH 7.4. The results showed that the encapsulation efficiency varied from 81 to 100% and the formulation fabricated from PLGA 85/15 (1:3) showed less burst and consistent long time release. This formulation when further characterized displayed irregular spherical shape with an average particle size of 72 µm. The crystallinity of the drug was reduced when investigated using X-ray diffractometry. No chemical interaction between the drug and the polymer was observed as evidenced by FT-IR analysis. The results indicated that beta-estradiol biodegradable microparticles with PLGA 85/15 (1:3) could be a suitable approach for long term therapy of osteoporosis.     

Surface periarterial spaces of the mouse brain are open,not porous

Fluid-dynamic models of the flow of cerebrospinal fluid in the brain have treated the perivascular spaces either as open (without internal solid obstacles) or as porous. Here, we present experimental evidence that pial (surface) periarterial spaces in mice are essentially open. (1) Paths of particles in the perivascular spaces are smooth, as expected for viscous flow in an open vessel, not diffusive, as expected for flow in a porous medium. (2) Time-averaged velocity profiles in periarterial spaces agree closely with theoretical profiles for viscous flow in realistic models, but not with the nearly uniform profiles expected for porous medium. Because these spaces are open, they have much lower hydraulic resistance than if they were porous. To demonstrate, we compute hydraulic resistance for realistic periarterial spaces, both open and porous, and show that the resistance of the porous spaces are greater, typically by a factor of a hundred or more. The open nature of these periarterial spaces allows significantly greater flow rates and more efficient removal of metabolic waste products.     

Grey is the new RGB: How good is GAN-based image colorization for image compression?

Multimedia Tools and Applications - GAN-based image colorization techniques are capable of producing highly realistic color in real-time. Subjective assessment of these approaches has demonstrated...