Effective Range of FSSW Parameters for High Load-Carrying Capacity of Dissimilar Steel A283M-C/Brass CuZn40 Joints

In the current study, a 2 mm thick low-carbon steel sheet (A283M—Grade C) was joined with a brass sheet (CuZn40) of 1 mm thickness using friction stir spot welding (FSSW). Different welding parameters including rotational speeds of 1000, 1250, and 1500 rpm, and dwell times of 5, 10, 20, and 30 s were applied to explore the effective range of parameters to have FSSW joints with high load-carrying capacity. The joint quality of the friction stir spot-welded (FSSWed) dissimilar materials was evaluated via visual examination, tensile lap shear test, hardness test, and macro- and microstructural investigation using SEM. Moreover, EDS analysis was applied to examine the mixing at the interfaces of the dissimilar materials. Heat input calculation for the FSSW of steel–brass was found to be linearly proportional with the number of revolutions per spot joint, with maximum heat input obtained of 11 kJ at the number of revolutions of 500. The temperature measurement during FSSW showed agreement with the heat input dependence on the number of revolution. However, at the same revolutions of 500, it was found that the higher rotation speed of 1500 rpm resulted in higher temperature of 583 °C compared to 535 °C at rotation speed of 1000 rpm. This implies the significant effect for the rotation speed in the increase of temperature. The macro investigations of the friction stir spot-welded joints transverse sections showed sound joints at the different investigated parameters with significant joint ligament between the steel and brass. FSSW of steel/brass joints with a number of revolutions ranging between 250 to 500 revolutions per spot at appropriate tool speed range (1000–1500 rpm) produces joints with high load-carrying capacity from 4 kN to 7.5 kN. The hardness showed an increase in the carbon steel (lower sheet) with maximum of 248 HV and an increase of brass hardness at mixed interface between brass and steel with significant reduction in the stir zone hardness. Microstructural investigation of the joint zone showed mechanical mixing between steel and brass with the steel extruded from the lower sheet into the upper brass sheet.     

The predictive value of intraoperative KT-1000 arthrometer measurements in single incision anterior cruciate ligament reconstruction

We reviewed 28 patients who underwent anterior cruciate ligament reconstruction with immediate, 1-, 2-, and 3-year postreconstruction KT-1000 manual maximum testing. Arthrometer measurements were correlated with functional knee criteria to evaluate the ability of the KT-1000 to predict postreconstruction functional results. Despite a range of immediate postreconstruction arthrometer injured-minus-normal (I - N) differences, there was no association with I - N difference at last follow-up. Patients followed-up for 1 year were not different from those who were followed-up for longer with respect to intraoperative or 1-year I - N difference or functional performance scores. Furthermore, excellent functional knee scores were the norm at all stages of follow-up despite a wide range of arthrometric laxity changes. The results suggest that functional knee criteria, although partially subjective, are more useful indicators of outcome than intrareconstruction and postreconstruction arthrometric measures.     

Use of streptokinase as a recall antigen for lymphocyte proliferation testing in vitro

The use of streptokinase (SK) as a recall antigen (Ag) for stimulation of human lymphocyte proliferation in vitro was evaluated. SK is a potent stimulant, inducing a greater response than three other Ags, tetanus toxoid, Candida albicans extract, or streptolysin. The optimum stimulatory concentration is 1000 U/ml, and peak stimulation occurs between days 6 and 8. Human cord-blood lymphocytes do not respond to SK, suggesting that it is an Ag and not a mitogen. The response rate in an adult population was 82%, higher than the rate of two other Ags tested (tetanus toxoid or Candida). These findings demonstrate the ability of SK to act as a potent recall Ag for human lymphocyte proliferation in vitro.     

Magnesium ascorbyl phosphate vesicular carriers for topical delivery; preparation,in-vitro and ex-vivo evaluation,factorial optimization and clinical assessment in melasma patients

Ascorbic acid (vitamin C) is an antioxidant that is widely used in cosmetics in skincare products. Due to the excessive low stability of ascorbic acid in cosmetic formulations, the stabilized ascorbic acid derivative, magnesium ascorbyl phosphate (MAP) was formulated as vesicular carriers; ethosomes and niosomes. The aim was to deliver MAP at the intended site of action, the skin, for sufficient time with enhanced permeation to get an effective response. Ethosomes were formulated using a full 3² factorial design to study ethanol and phospholipid concentration effect on ethosomes properties. Niosomes were formulated using 2³ factorial designs to study the effect of surfactant type, surfactant concentration and cholesterol concentration on niosomes properties. The prepared formulations were evaluated for their Entrapment efficiency, particle size, polydispersity index, zeta potential and % drug permeated. The optimized ethosomal and niosomal formulations were incorporated into carbopol gel and evaluated for their permeation, skin retention and stability. A comparative split-face clinical study was done between the ethosomal and niosomal formulations for melasma treatment using Antera 3 D^® camera. The optimized ethosomal and niosomal gels showed comparable controlled permeation and higher skin retention over their ethosomes and niosomes formulations respectively. Magnesium ascorbyl phosphate ethosomal gel showed clinically and statistically significant melanin level decrease after one month while MAP niosomal gel showed clinically and statistically significant melanin level decrease after six months. A combination of MAP ethosomes and niosomes could be promising skincare formulations for melasma and hyperpigmentation short and long-term treatment.     

Is Ustekinumab Effective in Refractory Crohn’s Disease of the Pouch and Chronic Pouchitis? A Systematic Review

Digestive Diseases and Sciences - Crohn’s disease (CD) of the pouch and chronic pouchitis represent the most common long-term complications of total proctocolectomy and ileal pouch anal...     

Lung ultrasound as a tool to guide respiratory physiotherapy

Lung ultrasound (LUS) is becoming an invaluable tool in the management of critically ill patients. We report two cases showing the importance of LUS as a guide to optimize respiratory physiotherapy in the intensive care unit, allowing a successful lung donation process and to redirect the physiotherapist's approach. The use of LUS requires an adequate training but it is becoming an important tool in management algorithms for critically ill patients.