Double Sided Incremental Forming: Capabilities and Challenges

Incremental Sheet Forming (ISF) is gaining importance because of its flexibility to form customized/low volume sheet metal parts. Out of different variants of ISF, Double Sided Incremental Forming (DSIF) is most flexible variant which uses two tools, one to form the geometry and the other to provide local support. Complex geometries with features on both sides of sheet can be formed in single setup by changing the roles of forming and supporting tools based on the geometrical characteristics. This article presents the evolution of DSIF process, machines, methodologies and strategies to form complex geometries and their prediction. A multi-stage methodology is attempted to enhance the accuracy of large components is presented. Results show that the accuracy of a 250 mm × 250 mm size conical component is enhanced by 50% (maximum error reduced from 2.9 mm to 1.4 mm) using two-stage forming

Trajectories of early childhood developmental skills and early adolescent psychotic experiences: Findings from the ALSPAC UK Birth Cohort

Objective: The aim of this study was to use prospective data from the Avon Longitudinal Study of Parents and Children (ALSPAC) to examine association between trajectories of early childhood developmental skills and psychotic experiences (PEs) in early adolescence. Method: This study examined data from n = 6790 children from the ALSPAC cohort who participated in a semi-structured interview to assess PEs at age 12. Child development was measured using parental report at 6, 18, 30, and 42 months of age using a questionnaire of items adapted from the Denver Developmental Screening Test - II. Latent class growth analysis was used to generate trajectories over time for measures of fine and gross motor development, social, and communication skills. Logistic regression was used to investigate associations between developmental trajectories in each of these early developmental domains and PEs at age 12. Results: The results provided evidence that decline rather than enduringly poor social (adjusted OR = 1.28, 95% CI = 1.10-1.92, p = 0.044) and communication skills (adjusted OR = 1.12, 95% CI = 1.03-1.22, p = 0.010) is predictive of suspected or definite PEs in early adolescence, than those with stable and/or improving skills. Motor skills did not display the same pattern of association; although gender specific effects provided evidence that only declining pattern of fine motor skills was associated with suspected and definite PEs in males compared to females (interaction OR = 1.47, 95% CI =1.09-1.97, p = 0.012). Conclusion: Findings suggest that decline rather than persistent impairment in social and communication skills were most predictive of PEs in early adolescence. Findings are discussed in terms of study's strengths, limitations, and clinical implications

Contrasting Effects of Varicose Vein Surgery on Endothelial-dependent and -independent Cutaneous Vasodilation in the Perimalleolar Region

AbstractObjectivesTo evaluate the effects of varicose vein surgery on cutaneous microvascular perfusion and vasodilator responses to acetylcholine (Ach) and sodium nitroprusside (SNP) in the gaiter area of patients with great saphenous vein insufficiency.MethodsTwenty-nine patients with isolated great saphenous vein incompetence attended three study mornings (before surgery, and 6–8 weeks and 6 months after sapheno-femoral ligation+partial stripping) during which cutaneous microvascular responses were measured in the supine and standing positions using laser Doppler fluximetry (LDF) combined with incremental-dose iontophoretic administration of endothelial-dependent (Ach) and -independent (SNP) vasodilators.ResultsVaricose vein surgery had no significant effect on baseline cutaneous perfusion or the microvascular response to Ach: e.g. peak vasodilator responses to the 1000μC stimulus were mean 58 SEM 7, 64 SEM 6 and 65 SEM 7PU on the pre-operative, 6–8 weeks and 6 months assessments. In contrast, the corresponding responses to SNP were significantly increased following surgery: e.g. at 2000μC, mean 63 SEM 9, 142 SEM 4 and 157 SEM 9PU (p<0.0001) in the upright position.ConclusionsSapheno-femoral ligation and partial stripping in patients with great saphenous vein insufficiency improves endothelial-independent cutaneous vasodilator function at the gaiter area, which may at least partly explain the benefits of surgery in reducing the risk of venous ulceration

Effects of lower limb angioplasty on endothelial-dependent and -independent microvascular reactivity

Background: Percutaneous Transluminal Angioplasty (PTA) of the lower limb improves arterial flow and claudication symptoms, but the effects on cutaneous microvascular perfusion and reactivity have not been previously reported. Report: Cutaneous microvascular function in the feet was assessed in 12 patients with intermittent claudication before and after PTA using Laser Doppler Fluximetry (LDF) with transcutaneous iontophoretic administration of acetylcholine and sodium nitroprusside. Maximum vasodilator responses to both endothelial-dependent and independent vasodilators were increased following PTA. Conclusions: Large vessel intervention to improve macrovascular flow has additional benefits on the downstreamcutaneous microcirculation to improve vasodilator responsiveness. These effects may be clinically important to reduce the risk of ischaemic ulceration and tissue breakdown

A Systematic Review of Magnesium Sulfate for Perinatal Neuroprotection: What Have We Learnt From the Past Decade?

There is an important unmet need to improve long term outcomes of encephalopathy for preterm and term infants. Meta-analyses of large controlled trials suggest that maternal treatment with magnesium sulfate (MgSO4) is associated with a reduced risk of cerebral palsy and gross motor dysfunction after premature birth. However, to date, follow up to school age has found an apparent lack of long-term clinical benefit. Because of this inconsistency, it remains controversial whether MgSO4 offers sustained neuroprotection. We systematically reviewed preclinical and clinical studies reported from January 1 2010, to January 31 2020 to evaluate the most recent advances and knowledge gaps relating to the efficacy of MgSO4 for the treatment of perinatal brain injury. The outcomes of MgSO4 in preterm and term-equivalent animal models of perinatal encephalopathy were highly inconsistent between studies. None of the perinatal rodent studies that suggested benefit directly controlled body or brain temperature. The majority of the studies did not control for sex, study long term histological and functional outcomes or use pragmatic treatment regimens and many did not report controlling for potential study bias. Finally, most of the recent preterm or term human studies that tested the potential of MgSO4 for perinatal neuroprotection were relatively underpowered, but nevertheless, suggest that any improvements in neurodevelopment were at best modest or absent. On balance, these data suggest that further rigorous testing in translational preclinical models of perinatal encephalopathy is essential to ensure safety and best regimens for optimal preterm neuroprotection, and before further clinical trials of MgSO4 for perinatal encephalopathy at term are undertaken