Refinement of primary Silicon crystals by novel Al-ZnS master alloy in solidification of Hypereutectic Al-Si Alloys

A novel Al-ZnS master alloy was developed by in situ reaction of Zn and Na2S in the Al melt. The results from this study left little doubt that this novel Al-ZnS master alloy was a promising refiner in solidification of hypereutectic Al-Si alloys. It refined the primary silicon to the same extent as that achieved by adding P via Cu-P following the same refinement mechanism. The SEM work confirmed that there were many pre-formed ZnS particles contained in the master alloy. The optical metallography showed that the morphologies of the primary silicon crystals in the solidified Al-22Si alloy were drastically changed from irregular coarse morphology to fine regular particles. The primary silicon crystal was refined from 74 m to 26, 22, 24 m by adding 0.05, 0.1, 0.15 wt% ZnS respectively with holding time of 20 min, where as the average particle size of the primary silicon refined by 200 ppm P reduced to 20 m. With the increase of the holding time up to 1.5 hr, the primary silicon size will increase up to 33 m in adding 0.1 wt% ZnS

Metallothionein induction reduces caspase-3 activity and TNFα levels with preservation of cognitive function and intact hippocampal neurons in carmustine-treated rats

Hippocampal integrity is essential for cognitive functions. On the other hand, induction of metallothionein (MT) by ZnSO4 and its role in neuroprotection has been documented. The present study aimed to explore the effect of MT induction on carmustine (BCNU)-induced hippocampal cognitive dysfunction in rats. A total of 60 male Wistar albino rats were randomly divided into four groups (15/group): The control group injected with single doses of normal saline (i.c.v) followed 24 h later by BCNU solvent (i.v). The second group administered ZnSO4 (0.1 µmol/10 µl normal saline, i.c.v, once) then BCNU solvent (i.v) after 24 h. Third group received BCNU (20 mg/kg, i.v, once) 24 h after injection with normal saline (i.c.v). Fourth group received a single dose of ZnSO4 (0.1 µmol/10 µl normal saline, i.c.v) then BCNU (20 mg/kg, i.v, once) after 24 h. The obtained data revealed that BCNU administration resulted in deterioration of learning and short-term memory (STM), as measured by using radial arm water maze, accompanied with decreased hippocampal glutathione reductase (GR) activity and reduced glutathione (GSH) content. Also, BCNU administration increased serum tumor necrosis factor-alpha (TNFα), hippocampal MT and malondialdehyde (MDA) contents as well as caspase-3 activity in addition to histological alterations. ZnSO4 pretreatment counteracted BCNU-induced inhibition of GR and depletion of GSH and resulted in significant reduction in the levels of MDA and TNFα as well as the activity of caspase-3. The histological features were improved in hippocampus of rats treated with ZnSO4 + BCNU compared to only BCNU-treated animals. In conclusion, MT induction halts BCNU-induced hippocampal toxicity as it prevented GR inhibition and GSH depletion and counteracted the increased levels of TNFα, MDA and caspase-3 activity with subsequent preservation of cognition

Pitfalls in the management of infantile renal neoplasia

This article addresses questions posed by a renal mass in early infancy. Are changes required in the standard approach to a renal mass in this age group? Are diagnostic possibilities transformed enough to warrant a change of approach in a setting like this? What are the ‘benign’ lesions that require consideration? What is the physician’s liability in performing a nephrectomy in a patient with a problem like this? A review of the literature suggests that the vast majority of renal space occupying lesions in children of this age are still Wilms’ tumor. Unless diagnostic refinements reach a higher level, the present protocols should be persisted with.Keywords: cystic nephroma, infancy, liability, pyelonephritis, renal mass, Wilms tumor, xanthogranulomatou

Reflection and Transmission of an Incident Progressive Wave by Obstacles in Homogeneous Shallow Water

The influence of a suspended fixed obstacle on an incident progressive wave inside an ideal homogeneous shallow water is studied in two dimensions. The fluid occupies an infinite channel of a constant depth, and a fixed obstacle of a small horizontal extent is partially submerged without contact with the bottom of the channel. An asymptotic double series expansion for the solution is used. The procedure enables us to calculate analytic expressions for the local perturbations up to the second order. The results of the first-order approximation indicate that no reflections exist. The second-order approximation of the solution is found to be the superposition of a progressive wave and local perturbations. For approximations of order higher than two, a secular term which increases monotonically with time and distance appears in the expressions for the progressive wave. This unacceptable result is due to a certain aspects in the mathematical procedure used. For this reason, the procedure is modified by using a suitable transformation of variables which reduces the determination of the transmitted wave to the solution of the KdV equation. As an illustration, the special case of the incident uniform flow is considered and the stream lines of the resulting flow are drawn

Acquired air-filled lung cysts in childhood: pathogenesis of cysts of diverse etiologies; nuances of management

Background Air-filled pulmonary parenchymal cysts (pneumatoceles/PCs) – a pathological condition – involving the lung parenchyma may be congenital or acquired. In children, acquired cases are often caused by staphylococcal pneumonias, but other etiologies may also cause PCs and lead to diagnostic confusion.Objectives The aim of this study was to examine the natural history and clinicopathologic features of noncongenital, nonstaphylococcal PCs in children.Patients and methods Four children with nonstaphylococcal PCs were included in this study. A full history, clinical examination, relevant radiological and pathological findings, surgical intervention where relevant, and follow-up were analyzed.Results The cases described represent acquired PCs: one occurred after infarction following cardiac surgery, another was a subpleural pulmonary bleb of inflammatory origin, and the remaining two were post-traumatic pseudocysts. The inflammatory-process bleb and the postinfarction cysts presented with pneumothorax. The postinfarction and post-traumatic PCs responded to observation. The pulmonary bleb was excised.Conclusion Our understanding of the clinicopathologic features and pathogenesis of many types of acquired PCs is incomplete. We propose that PC formation has a basis in destruction of the distal airways of the lung. Damaged tissue may act as a valve, and cause air-trapping, which leads to PC formation. Cysts arising after infarction or after trauma usually resolve on observation. Subpleural blebs may require excision because of nonresolution and recurrence of pneumothorax

Refinement and Modification of Silicon Phases in Solidification of High Purity Hypereutectic Al-15si Alloy

Engineering and Physical Sciences Research Council (EPSRC), U

Fe-Rich Intermetallic Formation and Mechanical Properties of Recycled AA6111 Alloy Strips Produced by Melt Conditioning Twin Roll Casting

The online version of this article (https://doi.org/10.1007/s11837-020-04324-z) contains supplementary material, which is available to authorized users.© 2020 The Author(s). The impact of high shear melt conditioning on the morphology and distribution of Fe intermetallic compounds was investigated in the processing of recycled AA6111 alloy by the twin roll casting process. The optical and scanning electron microscope (SEM) micrograph studies were carried out on twin roll casting (TRC) and melt conditioning twin roll casting (MC-TRC) samples. The microstructural analysis showed fine and uniformly distributed Fe-rich intermetallic phases for MC-TRC strips compared with the TRC strips. There was a significant improvement in the mechanical properties of MC-TRC strips after applying melt conditioning. The as-cast MC-TRC samples showed 18.7%, 19.2% and 9.8% increases in elongation, yield strength and ultimate tensile strength, respectively, in the longitudinal direction, while in the transverse section, the MC-TRC samples showed 32.3%, 2.2% and 3.8% increases in elongation, yield strength and ultimate tensile strength, respectively.Primetals Technologies, UK

Pro-inflammatory and oxidative stress pathways which compromise sperm motility and survival may be altered by L-carnitine

The testis is an immunologically privileged organ. Sertoli cells can form a blood-testis barrier and protect sperm cells from self-immune system attacks. Spermatogenesis may be inhibited by severe illness, bacterial infections and chronic inflammatory diseases but the mechanism(s) is poorly understood. Our objective is to help in understanding such mechanism(s) to develop protective agents against temporary or permanent testicular dysfunction. Lipopolysaccaride (LPS) is used as a model of animal sepsis while L-carnitine (LCR) is used as a protective agent. A total of 60 male Swiss albino rats were divided into four groups (15/group). The control group received Saline; the 2nd group was given LCR (500 mg/kg i.p, once). The third group was treated with LPS (5 mg/kg i.p once) and the fourth group received LCR then LPS after three hours. From each group, five rats were used for histopathological examination. Biochemical parameters were assessed in the remaining ten rats. At the end of the experiment, animals were lightly anaesthetized with ether where blood samples were collected and testes were dissected on ice. Sperm count and motility were evaluated from cauda epididymis in each animal. Also, oxidative stress was evaluated by measuring testicular contents of reduced glutathione (GSH), malondialdehyde (MDA) and 8-hydroxydeoxyguanosine (8-HDG, the DNA adduct for oxidative damage) in testicular DNA. The pro-inflammatory mediator nitric oxide (NO) in addition to lactate dehydrogenase (LDHx) isoenzyme-x activity as an indicator for normal spermatozoal metabolism were assessed in testicular homogenate. Serum interlukin (IL)-2 level was also assessed as a marker for T-helper cell function. The obtained data revealed that LPS induced marked reductions in sperm's count and motility, obstruction in seminiferous tubules, hypospermia and dilated congested blood vessels in testicular sections concomitant with decreased testicular GSH content and LDHx activity. Moreover, the testicular levels of MDA, 8-HDG (in testicular DNA) and NO as well as serum IL-2 level were increased. Administration of LCR before LPS returned both sperm count and motility to normal levels. Also, contents of testicular GSH, MDA, 8-HDG and NO returned back to the corresponding control values. In addition, serum IL-2 level as well as histological abnormalities were markedly improved in LCR + LPS-treated rats. In conclusion, LPS increased proinflammatory and oxidative stress markers in the testis leading to a marked testicular dysfunction. L-carnitine administration ameliorates these effects by antioxidant and/or anti-inflammatory mechanisms suggesting a protective role against male infertility in severely infected or septic patients

Direct Chill Casting and Extrusion of AA6111 Aluminum Alloy Formulated from Taint Tabor Scrap

© 2020 by the authors. AA6111 aluminum automotive body-sheet alloy has been formulated from 100% Taint Tabor scrap aluminum. Direct chill casting with and without high shear melt conditioning (HSMC) was used to produce the AA6111 alloy billets. Both homogenized and non-homogenized billets were extruded into sheets. The optical micrographs of the melt conditioned direct chill (MC-DC) samples showed refined equiaxed grains in comparison to direct chill (DC) cast and direct chill grain refined (DC-GR) samples. Optical metallography showed extensive peripheral coarse grain (PCG) for the DC, DC-GR and MC-DC planks extruded from the homogenized standard AA6111 billets while planks extruded from modified AA6111 billets (with recrystallization inhibitors) showed thin PCG band. The co-addition of recrystallization inhibitors Mn, Zr, and Cr with elimination of the billet homogenization step had a favorable impact on the microstructure of the AA6111 alloy following the extrusion process where a fibrous grain structure was retained across the whole section of the planks. The mechanical properties of as-cast planks extruded from non-homogenized billets were similar to those extruded from homogenized billets. Eliminating the homogenization heat treatment step prior to extrusion has important ramifications in terms of processing cost reductionInnovate UK/REALITY projec

Melt conditioned direct chill (MC - DC) casting and extrusion of AA5754 Aluminium alloy formulated from recycled Taint Tabor scrap

© 2020 by the authors. The melt conditioned direct chill (MC-DC) casting process has been used to produce billets and extruded planks of AA5754 alloy formulated from 100% recycled Taint Tabor scrap aluminum. The billets were homogenized and then extruded into flat planks. Optical metallography of the MC-DC cast billets showed equiaxed refined grains in comparison to conventional direct chill (DC) cast and direct chill grain refined (DC-GR) cast billets formulated from the same Taint Tabor scrap. Microstructural evaluation of the extruded planks showed extensive peripheral coarse grain (PCG) for the DC, DC-GR and MC-DC cast planks. The 2 mm and 1 mm MC-DC cast planks produced after cold rolling and heat treatment showed a fully recrystallized microstructure at 380 °C and 300 °C for 10 min respectively with an improvement in mechanical properties over DC-GR cast and similarly processed planks. The as-extruded MC-DC cast planks tensile tested in the transverse direction showed 34% elongation and 213 MPa ultimate tensile strength. These tensile results showed 5.8% higher elongation and 1.2% higher ultimate tensile strength compared with the DC-GR planks after applying high shear melt conditioning.BCAST; Innovate U