HIV Stigma,Homophobia, Sexual and Gender Minority Community Connectedness and HIV Testing Among Gay,Bisexual, and Other Men and Transgender People Who Have Sex with Men in Kazakhstan

AIDS and Behavior - Although HIV incidence is rising among gay, bisexual, and other men (MSM) and transgender people who have sex with men (TSM) in Kazakhstan, whether stigmatizing attitudes and...     

Exposure of the lysine in the gamma chain dodecapeptide of human fibrinogen is not enhanced by adsorption to poly(ethylene terephthalate) as measured by biotinylation and mass spectrometry

Conformational changes in adsorbed fibrinogen may enhance the exposure of platelet adhesive sites that are inaccessible in solution. To test this hypothesis, mass spectrometric methods were developed to quantify chemical modification of lysine residues following adsorption of fibrinogen to biomaterials. The quantitative method used an internal standard consisting of isotope-labeled fibrinogen secreted by human HepG2 cells in culture. Lysine residues in the internal standard were partially reacted with NHS-biotin. For the experimental samples, normal human fibrinogen was adsorbed to poly(ethylene terephthalate) (PET) particles. The adsorbed fibrinogen was reacted with NHS-biotin and then eluted from the particles. Constant amounts of internal standard were added to sample fibrinogen and analyzed by liquid chromatography/tandem mass spectrometry. Biotinylation of the lysine residue in the platelet-adhesive gamma chain dodecapeptide (GCDP) was quantified by comparison with the internal standard. Approximately 80% of the GCDP peptides were biotinylated when fibrinogen was reacted with NHS-biotin in solution or adsorbed onto PET. These results are generally consistent with previous antibody binding studies and suggest that other regions of fibrinogen may be crucial in promoting platelet adhesion to materials. The results do not directly address but are consistent with the hypothesis that only activated platelets adhere to adsorbed fibrinogen.     

Double CD38−/CD138− negative multiple myeloma

The standard diagnosis of multiple myeloma by flow cytometry is based on selection of population of CD38⁺/CD138⁺ positives cells. As the result treatment with proteasome inhibitors, CD138 may be underexpressed on atypical plasma cells. Thus, in order to improve this strategy, recently new CD138-independent method, based on CD38 positivity of plasma cells was developed. We present an unusual case of CD138^? negative multiple myeloma which had become double CD138^?/CD38^? negative after treatment with daratumumab by which we would like to illustrate potential pitfalls of both strategies.     

Rice Husk Research: From Environmental Pollutant to a Promising Source of Organo-Mineral Raw Materials

Rice husk is a large-tonnage waste left from rice production. It is not subject to humification and therefore becomes a serious environmental pollutant. Due to the presence of two essential elements—carbon and silicon—in its composition, rice husk is a promising organo-mineral raw material. The known methods for processing of rice husk are associated with the formation of even more aggressive waste. The creation of a waste-free technology for processing this plant material requires a detailed study. Rice husk of Kyzylorda oblast was studied using IR, SEM, TA, TPD-MS, EPR, and TEM methods. It was determined that under a temperature up to 500 °C, the ligno-carbohydrate component of rice husk decomposes almost completely. Three main peaks are recorded during the decomposition: hemicellulose at 200 °C, cellulose at 265 °C, and lignin at 350–360 °C. This process is endothermic. However, above of 300 °C the exothermic reactions associated with the formation of new substances and condensation processes in the solid residue begin to prevail. This explains the increase in the concentration of paramagnetic centers (PMCs) in products of rice husk carbonization in the range of up to 450 °C. Further increase in temperature leads to a decrease in the number of PMCs as a result of carbon graphite-like structures formation. The silicon–carbon product of rice husk carbonization (nanocomposite) is formed by interconnected nanoscale particles of carbon and silicon dioxide, the modification of which depends on the temperature of carbonization. The obtained data allow management of the rice husk utilization process while manufacturing products in demand based on ecofriendly technologies.     

Exploring the Factors Affecting the Solubility of Chitosan in Water

We explore the role of crystallinity and inter‐ or intramolecular forces in chitosan for its solubility in water and demonstrate the expansion of its solubility to a wider pH range. Due to its semicrystalline nature, derived mainly from inter‐ and intramolecular hydrogen bonds, chitosan is water‐soluble only at pH < 6. In acidic conditions, its amino groups can be partially protonated resulting in repulsion between positively charged macrochains, thereby allowing diffusion of water molecules and subsequent solvation of macromolecules. We show that chemical disruption of chitosan crystallinity by partial re‐acetylation or physical disruption caused by the addition of urea and guanidine hydrochloride broadens the pH‐solubility range for this biopolymer.

     

A rationally assembled microbial community for growing Tagetes patula L. in a lunar greenhouse

Well-defined plant-associated bacteria were used for growing French marigolds (Tagetes patula L.) in anorthosite, a substrate of low bioavailability, analogous to a lunar rock. The consortium was composed mainly of plant growth-promoting rhizobacteria and biocontrol agents that were used for seed inoculation. Simultaneously, the sterile substrate was inoculated with the siliceous bacterium Paenibacillus sp. IMBG156. The plant benefited from bacterial activity which resulted in stimulation of seed germination, better plant development, and finally in flowering of inoculated tagetes. In contrast, control plants grew poorly in sterile anorthosite and never flowered. Analysis of bacterial community composition showed that both species colonized plant roots, and there were no shifts in the consortium structure in the rhizosphere of French marigolds within 6 weeks. Paenibacillus sp. IMBG156 was able to release some elements (Ca, Fe, Si) from substrate anorthosite. It was assumed that a rationally assembled consortium of bacterial strains supported growth and development of the model plant under growth-limiting conditions, at least by means of bioleaching and delivering of essential nutritional elements to the plants, and by promoting plant growth.     

A wireless multi-channel neural amplifier for freely moving animals

Conventional neural recording systems restrict behavioral experiments to a flat indoor environment compatible with the cable that tethers the subject to recording instruments. To overcome these constraints, we developed a wireless multi-channel system for recording neural signals from rats. The device takes up to 64 voltage signals from implanted electrodes, samples each at 20 kHz, time-division multiplexes them into one signal and transmits that output by radio frequency to a receiver up to 60 m away. The system introduces <4 μV of electrode-referred noise, comparable to wired recording systems, and outperforms existing rodent telemetry systems in channel count, weight and transmission range. This allows effective recording of brain signals in freely behaving animals. We report measurements of neural population activity taken outdoors and in tunnels. Neural firing in the visual cortex was relatively sparse, correlated even across large distances and was strongly influenced by locomotor activity.     

Interlayer Bond Strength Testing in 3D-Printed Mineral Materials for Construction Applications

There are no standards for testing the properties of 3D-printed materials; hence, the need to develop guidelines for implementing this type of experiment is necessary. The work concerns the development of a research methodology for interlayer bond strength evaluation in 3D-printed mineral materials. In additive manufactured construction elements, the bond strength is a significant factor as it determines the load-bearing capacity of the entire structural element. After we completed a literature review, the following three test methods were selected for consideration: direct tensile, splitting, and shear tests. The paper compares the testing procedure, results, and sample failure modes. The splitting test was found to be the most effective for assessing layer adhesion, by giving the lowest scatter of results while being an easy test to carry out.