Mitigating Inhomogeneity and Tailoring the Microstructure of Selective Laser Melted Titanium Orthorhombic Alloy by Heat Treatment,Hot Isostatic Pressing,and Multiple Laser Exposures

Titanium orthorhombic alloys based on intermetallic Ti₂AlNb-phase are attractive materials for lightweight high-temperature applications. However, conventional manufacturing of Ti₂AlNb-based alloys is costly and labor-consuming. Additive Manufacturing is an attractive way of producing parts from Ti₂AlNb-based alloys. High-temperature substrate preheating during Selective Laser Melting is required to obtain crack-free intermetallic alloys. Due to the nature of substrate preheating, the temperature profile along the build height might be uneven leading to inhomogeneous microstructure and defects. The microstructural homogeneity of the alloy along the build direction was evaluated. The feasibility of mitigating the microstructural inhomogeneity was investigated by fabricating Ti₂AlNb-alloy samples with graded microstructure and subjecting them to annealing. Hot isostatic pressing allowed us to achieve a homogeneous microstructure, eliminate residual micro defects, and improve mechanical properties with tensile strength reaching 1027 MPa and 860 MPa at room temperature and 650 °C, correspondingly. Annealing of the microstructurally graded alloy at 1050 °C allowed us to obtain a homogeneous B2 + O microstructure with a uniform microhardness distribution. The results of the study showed that the microstructural inhomogeneity of the titanium orthorhombic alloy obtained by SLM can be mitigated by annealing or hot isostatic pressing. Additionally, it was shown that by applying multiple-laser exposure for processing each layer it is possible to locally tailor the phase volume and morphology and achieve microstructure and properties similar to the Ti2AlNb-alloy obtained at higher preheating temperatures.     

Assessment of gender and age effects on serum and hair trace element levels in children with autism spectrum disorder

Metabolic Brain Disease - The primary objective of the present study was to investigate the levels of essential trace elements in hair and serum in children with autism spectrum disorder (ASD) and...     

Identification and Management of Patients at Elevated Cardiometabolic Risk in Canadian Primary Care: How Well Are We Doing?

Background

We evaluated the risk assessment and management patterns employed by primary care physicians in patients at elevated cardiometabolic risk.

Methods

Between April 2011 and March 2012, multiple physicians from 9 Primary Care Teams (PCTs) and 88 physicians from traditional nonteam (Solo) practices completed a practice assessment on the management of 2461 patients > 40 years old with no clinical evidence of cardiovascular disease and diagnosed with at least 1 of the following: dyslipidemia, type 2 diabetes mellitus (T2DM), or hypertension.

Results

Individuals with dyslipidemia, T2DM, or hypertension tended to have a body mass index ≥ 25 kg/m². Waist circumference measurements, obtained for only 392/829 (47.0%) Solo patients, revealed that 88.9% of these individuals were abdominally obese and that at least 52.2% of Solo patients had metabolic syndrome. Cardiovascular risk, determined by the physicians for 83.5% of all patients without T2DM and typically performed using traditional risk engines, was often miscalculated (43.2% PCTs, 58.8% Solo; P = 0.0007). Healthy behavioural modifications were infrequently recommended (< 50%). Pharmacotherapy was widely used (> 70%) but treatment targets were infrequently met. The composite outcome of guideline-recommended low-density lipoprotein cholesterol, glycemic, and blood pressure targets was met by 9.0% and 8.1% of patients managed by PCT and Solo physicians respectively.

Conclusions

Obesity and cardiovascular risk were underassessed and the latter often underestimated. Patients were infrequently counselled on the benefits of healthy behavioural changes. A paradigm change in assessing and managing obesity and cardiovascular risk via aggressive lifestyle interventions is warranted in individuals at elevated cardiometabolic risk.     

Effect of protein load on kidney functions in patients with chronic glomerulonephritis

AIM: To study changes in renal function in response to protein loads in patients with chronic glomerulonephritis (CGN) who have normal renal function and initial uremia. MATERIAL AND METHODS: 63 CGN patients were divided into two groups: 40 patients of group 1 (17 males, 23 females, age 16-53 years, plasma creatinine-Pcr < 0.132 mmol/l); 23 patients of group 2 (10 males, 13 females, age 18-57 years, Pcr > 0.132 mmol/l). Renal functional reserve (RFR) was assessed with oral soa isolate SUPRO 760 test (protein Techn. Int., USA), 1.0 g of protein per 1 kg of ideal body mass. By three 2-h clearance periods measurements were made of RFR, absolute and fractional excretion, concentration indices and clearances of creatinine, urea, electrolytes, osmolality. All the parameters were referred to the standard body surface. RESULTS: RFR was intact in 14 patients of group 1 and 10 patients of group 2. In CGN without uremia with intact RFR, maximal Pcr corresponded to the highest values of minute diuresis and sharp increase of urea excretion, osmotically active substances. In CGN patients with uremia and intact RFR, development of hyperfiltration was accompanied with a significant rise in Pcr, minute diuresis, absolute excretion of urea and osmotically active substances. The rise in the latter two was much less active in CGN if RFR was absent. Multiple stepwise regression analysis showed that RFR intactness depends primarily on baseline values of absolute excretion of urea and osmotically active substances. CONCLUSION: A reverse relationship exists between absolute excretion of urea, osmotically active substances and the degree of SKF in response to protein load in CGN patients both in intact nitrogen-excreting function and uremia. It is suggested that urea may be involved in regulation of intraglomerular hemodynamics by means of effect on tubular-glomerular feedback mechanism.     

Evaluation of 99mTc(CO)5I as a potential lung perfusion agent

IntroductionThe use of ^99mTc-macroggregated albumin for lung perfusion imaging is well established in nuclear medicine. However, there have been safety concerns over the use of blood-derived products because of potential contamination by infective agents, for example, Variant Creutzfeldt Jakob Disease. Preliminary work has indicated that Tc(CO)₅I is primarily taken up in the lungs following intravenous administration. The aim of this study was to evaluate the biodistribution and pharmacokinetics of ^99mTc(CO)₅I and its potential as a lung perfusion agent.Methods^99mTc(CO)₅I was synthesized by carbonylation of ^99mTcO_4? at 160 atm of CO at 170°C in the presence of HI for 40 min. Radiochemical purity was determined by HPLC using ⁹⁹Tc(CO)₅I as a reference. ^99mTc(CO)₅I was administered by ear-vein injection to three chinchilla rabbits, and dynamic images were acquired using a gamma camera (Siemens E-cam) over 20 min. Imaging studies were also performed with ^99mTc-labeled macroaggregated albumin (^99mTc-MAA) and ^99mTcO_4? for comparison. ^99mTc(CO)₅I was administered intravenously to Sprague–Dawley rats, and tissue distribution studies were obtained at 15 min and 1 h postinjection. Comparative studies were performed using ^99mTc-MAA.ResultsRadiochemical purity, assessed by HPLC, was 98%. The retention time was similar to that of ⁹⁹Tc(CO)₅I. The dynamic images showed that 70% of ^99mTc(CO)₅I appeared promptly in the lungs and remained constant for at least 20 min. In contrast, ^99mTcO_4? rapidly washed out of the lungs after administration. As expected ^99mTc-MAA showed 90% lung accumulation. The percentage of injected dose per gram of organ ±S.D. at 1 h for ^99mTc(CO)₅I was as follows: blood, 0.22±0.02; lung, 12.8±2.87; liver, 0.8±0.15; heart, 0.15±0.01; kidney, 0.47±0.08. The percentage of injected dose per organ ±S.D. at 1 h was as follows: lung, 22.47±2.31; liver, 10.53±1.8; heart, 0.18±0.01; kidney, 1.2±0.17. Tissue distribution studies with ^99mTc-MAA showed 100% lung uptake.Conclusion^99mTc(CO)₅I was synthesized with a high radiochemical purity and showed a high accumulation in the lungs. Further work on the mechanism and optimization of lung uptake of ^99mTc-pentacarbonyl complexes is warranted.     

Evaluation of the effectiveness of differentiated therapy in patients with chronic erosions of the gastric mucosa

Potentialities of differentiated therapy of patients with recurrent chronic erosions using medicinal and nonmedicinal methods in 119 patients were studied. During differentiated therapy one should take into account the condition of pathological microflora and circulatory disturbances. At the first stage routine therapy with subsequent incorporation of biogastrone was employed. At the second stage in the absence of a therapeutic effect local administration of a granulocytic concentrate was performed, and in insufficient effectiveness, electrocoagulation of chronic erosions of the gastric mucosa was indicated. The use of differentiated therapy contributed to a favorable prognosis of disease in these patients.