Titanium mesh-reinforced calcium sulfate for structural bone grafts

Calcium sulfate (CS) possesses many of the requirements for an ideal bone graft material: it is biodegradable, biocompatible, and osteoconductive. However, its relatively low strength and brittleness are major obstacles to its use as a structural bone implant. Although the strength of CS can be improved by reducing porosity, its brittleness remains a major obstacle towards its use as bone graft. Here we combine two powerful toughening strategies which are found in advanced ceramics and in natural bone: Multi-layered architectures and ductile reinforcements. We first used stress analysis and micromechanics to generate design guidelines that ensure the proper failure sequence and maximize properties. We then fabricated and tested fully dense CS by hydrostatic compression layered with layers of titanium woven mesh. Flexural experiments in hydrated conditions confirmed that the ductility and strength of titanium and the adhesion at the titanium-CS interfaces (controlled by the size of the Ti mesh) are critical factors in the mechanical performance of the composite. Our best design exhibited a toughness 180 times larger than that of plain CS, together with a 46% increase in strength.</p

Biochemical parameters and pathogenesis of SARS-CoV-2 infection in vital organs: COVID-19 outbreak in Iran

Since its emergence, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread worldwide, and led to ever-increasing mortality. SARS-CoV-2 infection perturbs the function of the body's vital organs, making patients of all ages susceptible to the disease. Nevertheless, individuals developing critical illness with poor outcomes were mostly the elderly and people with co-morbid conditions, who constituted the vast majority of coronavirus disease 2019 (COVID-19) fatalities. Complications of COVID-19 mostly involve the respiratory, renal and cardiovascular systems, and in severe cases secondary infections leading to pneumonia and acute respiratory distress syndrome, which may precede the death of the patient. Multi-organ failure in individuals with COVID-19 could be a consequence of their co-morbidities. A patient's pre-existing conditions may affect the disease prognosis, requiring immediate attention to accurately detect and evaluate them in SARS-CoV-2-infected individuals. This review addresses several issues in relation to manifestations of the body's vital organs along with potential diagnostic blood factors in SARS-CoV-2 infection. It is hoped that the review will lead to more comprehensive understanding of this complex disease. © 2020 The Author

Study of Path Coefficients Analysis for Grain Yield and Yield Components in Durum Wheat under Drought Stress and Non-stress Conditions

The purpose of this study was to describe the correlations between wheat grain yield (GY) and its components, under environmental stress and non-stress conditions, and recognition of the most effective yield components and their development stages in making interaction with the environment. Two generations of F3 and F4, produced from a cross between Oste-Gata (drought tolerant) and Massara-1 (susceptible) genotypes, were used for evaluation in two years (2005 and 2006) at Research Farm of Isfahan University of Technology, Isfahan, Iran. Analysis of correlation of yield and yield components showed that grain yield was significantly correlated with grain weight per spike, number of grains per spike and number of spikes per m2. Results of Tai analysis revealed that under stress, grain weight per spike and under non-stress condition, number of spikes per m2 had the highest direct effect on GY in both generations. Assay of genotypic components showed that under stress conditions, grain weight per spike and number of grains per spike, and under non-stress conditions, number of spikes per m2 had the highest effect on genotype × environment interaction and their developmental stages (grain filling, reproductive and pollination). In non-stress condition, spike number per m2 had the same effect. Analysis of environmental components indicated that the most environmental sensitive period of plant growth was grain filling stage. Large difference between early and late growth stages is related to high sensitivity of grain filling period and reproductive stage to environmental conditions and the occurrence of drought stress at reproductive stage. Therefore, trend of grain yield variations under stress conditions was affected by grain weight per spike and showed the highest amount of environmental interaction at its growth stag

Identification of microsatellite markers associated with grain protein content in durum wheat grown under drought stress at terminal growth stages

Grain protein content (GPC) in durum wheat is a crucial determinant of pasta quality and as such is an important economic factor. This study was carried out to determine the microsatellite markers (SSRs) as associated with GPC in durum wheat grown under normal and moisture stress conditions. F3 and F4 population derived from 151 F2 individuals developed from a cross between Oste-Gata (drought tolerant) and Massara-1 (drought susceptible) genotypes, were used. The population was evaluated under four environmental conditions (two irrigation regimes in two growing seasons). The results of single marker regression analysis (SMA) revealed that 2, 4 and 10 markers to be associated with GPC, test weight (TW) and 1000 grain weight (TGW), respectively. These markers explained between 4.4 and 21.8% of the phenotypic variation in either environmental condition. The most significant marker observed for GPC was located on 5B chromosome near Xgwm408 under normal conditions and the other marker was observed on 1A, explaining about 15% of phenotypic variance. However, it was not recognized any marker related to GPC under drought stress conditions. Xgwm408 marker was coincident with the markers identified for TW, TGW and components of grain yield under drought stress conditions. In spite of 5B, the other chromosomes such as 2B and 3B were related to quantitative traits like TW and TGW. Composite interval mapping (CIM) identified 4 and 5 putative minor and major QTL for TW and TGW, respectively. Two QTL near Xbarc101 and Xbarc124 markers on 3B and 2B chromosome, explained up to 45.2 and 6% of phenotypic variations of TGW and TW, respectively

Configuration of flowsheet and reagent dosage for gilsonite flotation towards the ultra-low-ash concentrate

Gilsonite has a wide variety of applications in the industry, including the manufacture of electrodes, paints and resins, as well as the production of asphalt and roof-waterproofing material. Gilsonite ash is a determining parameter for its application in some industries (e.g., gilsonite with ash content < 5 used as an additive in drilling fluids, resins). Due to the shortage of high grade (low ash) gilsonite reserves, the aim of this study is to develop a processing flowsheet for the production of ultra-low-ash gilsonite (< 5), based on process mineralogy studies and processing tests. For this purpose, mineralogical studies and flotation tests have been performed on a sample of gilsonite with an average ash content of 15. According to mineralogical studies, carbonates and clay minerals are the main associated impurities (more than 90 vol.). Furthermore, sulfur was observed in two forms of mineral (pyrite and marcasite) and organic in the structure of gilsonite. Most of these impurities are interlocked with gilsonite in size fractions smaller than 105 µm. The size fraction of + 105 � 420 µm has a higher pure gilsonite (approximately 90) than other size fractions. By specifying the gangue minerals with gilsonite and the manner and extent of their interlocking with gilsonite, + 75 � 420 µm size fraction selected to perform flotation tests. Flotation tests were performed using different reagents including collector (Gas oil, Kerosene and Pine oil), frother (MIBC) and depressant (sodium silicate, tannic acid, sulfuric acid and sodium cyanide) in different dosages. Based on the results, the use of kerosene collector, MIBC frother and a mixture of sodium silicate, tannic acid, sulfuric acid and sodium cyanide depressant had the most favorable results in gilsonite flotation in the rougher stage. Cleaner and recleaner flotation stages for the rougher flotation concentrate resulted in a product with an ash content of 4.89. Due to the interlocking of gilsonite with impurities in size fractions � 105 µm, it is better to re-grinding the concentrate of the rougher stage beforehand flotation in the cleaner and recleaner stages. Finally, based on the results of mineralogical studies and processing tests, a processing flowsheet including crushing and initial granulation of gilsonite, flotation in rougher, cleaner and recleaner stages has been proposed to produce gilsonite concentrate with < 5 ash content. © 2021, The Author(s)