Microstructural Characteristics and Hardness Enhancement of Super Duplex Stainless Steel by Friction Stir Processing

In the present study, microstructural evolution and hardness of the friction stir processed (FSPed) SAF 2507 super duplex stainless steel fabricated at a rotational speed of 650 rpm and a traverse speed of 60 mm/min were investigated. A scanning electron microscope (SEM) equipped with an electron backscatter diffraction (EBSD) detector was used to study the microstructure of the stir zone. The grain sizes of austenite and ferrite in the FSPed 2507 were found to be smaller (0.75 and 0.96 μm) than those of the substrate (6.6 and 5.6 μm) attributed to the occurrence of continuous dynamic recrystallization (CDRX) in both phases. Higher degree of grain refinement and DRX were obtained at the advancing side of the FSPed specimens due to higher strain and temperature. A non-uniform hardness distribution was observed along the longitudinal direction of the SZ. The maximum hardness was obtained at the bottom (407 HV₁).     

Validation of the Powder Metallurgical Processing of Duplex Stainless Steels through Hot Isostatic Pressing with Integrated Heat Treatment

Duplex stainless steels exhibit an excellent combination of corrosion resistance and strength and are increasingly being manufactured through powder metallurgy (PM) to produce large, near-net-shaped components, such as those used for offshore applications. Hot isostatic pressing (HIP) is often used for PM production, in which pre-alloyed powders are compacted under high pressures and temperatures. Recent developments in HIP technology enable fast cooling as part of the process cycle, reaching cooling rates comparable to oil quenching or even faster. This enables the integrated solution annealing of duplex stainless steels directly after compaction. In contrast to the conventional HIP route, which requires another separate solution annealing step after compaction, the integrated heat treatment within the HIP process saves both energy and time. Due to this potential gain, HIP compaction at a high pressure of 170 MPa and 1150 °C with integrated solution annealing for the production of duplex stainless steels was investigated in this work. Firstly, the focus was to investigate the influence of pressure on the phase stability during the integrated solution annealing of the steel X2CrNiMoN22-5-3. Secondly, the steel X2CrNiMoCuWN25-7-4, which is highly susceptible to sigma phase embrittlement, was used to investigate whether the cooling rates used in the HIP are sufficient for preventing the formation of this brittle microstructural constituent. This work shows that the high pressure used during the solution heat treatment stabilizes the austenite. In addition, it was verified that the cooling rates during quenching stage in HIP are sufficient for preventing the formation of the sigma phase in the X2CrNiMoCuWN25-7-4 duplex stainless steel.     

Assessment of incidence of cerebral vascular diseases and prediction of stroke risk in chronic obstructive pulmonary disease patients using multimodal biomarkers

Background

Early assessment of cerebrovascular disease in chronic obstructive pulmonary disease (COPD) patients is an important issue for a favorable influence on the quality of life.

Methodology

This cross-sectional case–control study was conducted on 38 eligible COPD patients (mean age 55.5 ± 11.5, 25 males, and 13 females) and 26 age-/sex-matched healthy controls. All participants were subjected to stroke risk screening instruments that included the Stroke Riskometer™, the Framingham 10-Year Risk Score, the stroke risk screening tool (the Department of Disease Control of Thailand), the My Risk Stroke Calculator, and Q Stroke. Radiologically, diffusion tensor imaging (DTI) and echo-gradient MRI (T2 star) T2 star imaging were done. Color-coded duplex sonography was done. Laboratory investigations included C-reactive protein (CRP), serum amyloid A, plasma fibrinogen level, serum IL6, 8-Isoprostane, vWF and urinary albumin creatinine ratio.

Results

Stroke risk screening instruments revealed a significant increase in COPD patients. DTI showed a significant bilateral reduction in fractional isotropy and a significant bilateral increase in mean diffusivity of white matter through many areas in COPD patients. Patients also had a significant increase of intima–media thickness, presence of atherosclerotic focal thicknesses or plaques on duplex sonography. There was a significant elevation of CRP, serum amyloid A, plasma fibrinogen level, serum IL6, 8-isoprostane, von Willebrand factor (vWF), and urinary albumin creatinine ratio in COPD patients.

Conclusion

COPD patients had an increased risk for stroke that could be assessed on stroke risk screening instruments, DTI, T2 star, duplex sonography, and laboratory investigation and could be correlated with the severity of the disease.     

Application of percutaneous nephrolithotomy combined with da Vinci Xi robot in complicated upper urinary tract repair surgery: A case report

Duplex kidney and ureter is a congenital malformation. Few patients present with hydronephrosis caused by obstruction of the ureteropelvic junction of the duplex kidney, but lower kidney calculi caused by a duplex kidney abnormality is rare. This study reports a case of a duplex kidney and ureter complicated by multiple calculi in the duplex lower kidney. Percutaneous nephrolithotomy combined with a da Vinci robot-assisted laparoscopic upper urinary tract reconstruction was performed. The lower ureter was resected, and the lower kidney was preserved. One year after the surgery, a follow-up examination reported satisfactory renal function without hydronephrosis or calculi.     

Current landscape of kidney allocation: Organ procurement organization perspectives

Organ procurement organizations (OPOs) play a central role in the recovery, preservation, and distribution of deceased donor kidneys for transplantation in the United States. We conducted a national survey to gather information on OPO practices and perceived barriers to efficient organ placement in the face of the new circle-based allocation and asked for suggestions to overcome them. Of the 57 OPOs, 44 responded (77%). The majority of OPOs (61%) reported barriers to obtaining a kidney biopsy, including lack of an available pathologist. Most OPOs (55%) indicated barriers to pumping owing to a lack of available staff and transportation. Respondents agreed or strongly agreed that the new allocation system has worsened transportation challenges (85%), increased provisional acceptances of kidneys (66%), increased communication challenges with transplant centers (68%), and worsened the efficiency of organ allocation (83%). OPO-suggested solutions include making transplant centers more accountable for inefficient selection practices, developing reliable transportation options, and removing the requirement for national sharing. These findings underscore the need to examine closely the trade-offs of the new allocation system with respect to costs, organ ischemia, and discard. These findings may help inform practice and policy for overcoming transportation barriers and improving the efficiency of organ placement.     

Filler injections in the pre-auricular space: Be aware of the parotid gland

Backgroud

In recent years the pre-auricular area is increasingly used for filler injections.

Aims

Assessment of depth of the subcutaneous fat and the process of realtime filler injection.

Materials & Methods

Ultrasonographic data of two cases and a video are studied.

Results

These show how filler injections may very easily be delivered inside the parotid gland. This may go unnoticed by injector and client.

Discussion

This study and data from literature prove that filler injections in the pre-auricular area may end up inside or in the vicinity of the parotid gland, and this can lead to an inflammatory response.

Conclusion

It is recommended to be careful with filler injections in this area. Prior sonographic assessment of the subcutaneous depth in this area is advised.     

Crossing Algorithm for Infrainguinal Chronic Total Occlusions: An Interdisciplinary Expert Opinion Statement

A crossing algorithm was developed for the endovascular treatment of peripheral chronic total occlusive lesions (CTOs) to educate, guide, and appropriately influence clinical practice aiming at harmonization and standardization of endovascular procedures. The following steps are proposed: One, duplex sonography and if required computed tomography or magnetic resonance angiography for the selection of the optimal access site. Two, angiographic evaluation of the proximal/distal cap morphology, presence of collaterals at the origin of the proximal cap and at the distal vessel refilling site. In addition, evaluation of distal vessels, including their diameters and quality, and the presence of calcification or stents within the occlusion zone. Three, antegrade wiring strategies, guidewire (GW) and support catheter technology, as well as GW escalation strategies. Stop the antegrade attempt depending on clinical indication for peripheral artery disease treatment and the presence of retrograde options. Four, retrograde access site, support catheter, or sheath insertion and wiring technology from distally. Five, considering strategy change when progress cannot by achieved, using advanced bidirectional techniques and re-entry devices. Six, in case of successful GW passage from retrograde, GW externalization and treatment from antegrade. Management of the retrograde access by internal or external hemostasis at the end of the procedure. Alternatively, stop the procedure if no progress can be obtained within 3 hours or in case of specific complications. By establishing the algorithm in the daily routine of endovascular specialists, improvements in vessel- and patient-specific outcomes are anticipated. In addition, future research, and continuous collaboration between experts is warranted.