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Ramberg-Osgood (R-O) type stress-strain models are commonly employed during elasto-plastic analysis of metals. Recently, 2-stage and 3-stage R-O variant models have been proposed to replicate stress-strain behavior under large plastic deformation. The complexity of these models increases with the addition of each stage. Moreover, these models have considered deformation till necking only. In this paper, a simplistic multi-stage constitutive model is proposed to capture the strain-hardening non-linearity shown by metals including its post necking behavior. The constitutive parameters of the proposed stress-strain model can be determined using only elastic modulus and yield strength. 3-D digital image correlation was used as an experimental tool for measuring full-field strains on the specimens, which were subsequently utilized to obtain the material parameters. Our constitutive model is demonstrated with an aerospace-grade stainless steel AISI 321 wherein deformation response averaged over the gauge length (GL) and at a local necking zone are compared. The resulting averaged and local material parameters obtained from the proposed model provide interesting insights into the pre and post necking deformation behavior. Our constitutive model would be useful for characterizing highly ductile metals which may or may not depict non-linear strain hardening behavior including their post necking deformations. [ABSTRACT FROM AUTHOR]

Abstract Introduction Purple Glove Syndrome is a devastating complication of intravenous phenytoin administration. Adequate analgesia and preservation of limb movement for physiotherapy are the two essential components of management. Case presentation A 26-year-old Tamil woman from India developed Purple Glove Syndrome after intravenous administration of phenytoin. She was managed conservatively by limb elevation, physiotherapy and oral antibiotics. A 20G intravenous cannula was inserted into the sheath of her brachial plexus and a continuous infusion of bupivacaine at a low concentration (0.1%) with fentanyl (2 μg/ml) at a rate of 1 to 2 ml/hr was given. She had adequate analgesia with preserved motor function which helped in physiotherapy and functional recovery of the hand in a month. Conclusion A continuous blockade of the brachial plexus with a low concentration of bupivacaine and fentanyl helps to alleviate the vasospasm and the pain while preserving the motor function for the patient to perform active movements of the finger and hand.

Background  Pronator quadratus (PQ) is a deeply situated muscle in the forearm which may occasionally be utilized for soft-tissue reconstruction. The purpose of this anatomical and clinical study was to confirm vascular supply of PQ muscle (PQM) in order to optimize its transfer and confirm its utility in clinical situations. Methods  In Part A of the anatomical study, fresh human cadavers (n = 7) were prepared with an intra-arterial injection of lead oxide and gelatin solution, and PQM and neurovascular pedicle were dissected (n = 14). In the anatomical study Part B, isolated limbs of embalmed human cadavers (n = 12) were injected with India ink-gelatin mixture and PQ were dissected. Results  PQ is a type II muscle flap, with one major pedicle, the anterior interosseous (AI) vessels and two minor pedicles from the radial and ulnar vessels. The mean dimensions of the muscle were 5.5 × 5.0 × 1.0 cm 3 , mean pedicle length was 9.6 cm, and the mean diameter of the artery and the vein was 2.3 mm and 2.8 mm, respectively. The dorsal cutaneous perforating branch (DPB) of the artery supplied the skin over the dorsal forearm and wrist. This branch also anastomosed with the 1, 2 intercompartmental supraretinacular artery (ICSRA). Conclusion  This study confirms the potential utility and vascular basis of the PQM flap and its associated cutaneous paddle. In the clinical part, two patients with nonhealing wounds exposing the median nerve and flexor tendons in the distal forearm were treated using the PQM flap with good results. [ABSTRACT FROM AUTHOR]

Necrotizing soft tissue infection (NSTI) of the upper extremities is a rare, but potentially life-threatening infection in patients with type 2 diabetes mellitus (T2DM). We analyzed the clinical characteristics and the outcome of NSTI of upper extremities in these patients. This was a retrospective study analyzing the clinical characteristics and the outcomes of 33 T2DM patients with NSTI of upper extremities, who were treated in the department of hand surgery between January 2011 and December 2017. Predisposing factors for NSTI were recognized in 16 (48.5%) patients. Eleven (33.3)% patients had septic shock while ten (30.3%) had acute renal insufficiency at the time of presentation, of which six required dialysis. The mean glycosylated hemoglobin was 9.6(±2.6)% and the random plasma glucose at admission was 271(±96) mg/dl. Monomicrobial infection was seen in 16(49%) patients and polymicrobial infection in 9(27%) patients. Gram-positive causation was found in 25(66%) patients. Twelve (36.4%) patients required amputation, six (18.2%) of which were major. Death occurred in more than one-fifth (21.2%) of the patients during treatment. Necrotizing soft tissue infection of the upper extremities in T2DM is associated with increased risk of severe infection, amputation and mortality. • Necrotizing soft tissue infection of the upper extremities is a life-threatening infection in patients with diabetes mellitus. • Poor glycaemic control, delays in presentation and prior surgical intervention at another hospital are associated with more severe form of infection. • Early clinical recognition, prompt surgical intervention and intensive medical treatment can improve the outcomes. [ABSTRACT FROM AUTHOR]

Background: Mounting evidence showed the self-reported levels of physical activity are positively associated with white matter (WM) integrity and cognitive performance in normal adults and patients with mild cognitive impairment (MCI). However, the objective measure of cardiorespiratory fitness (CRF) was not used in these studies.Objective: To determine the associations of CRF measured by maximal oxygen uptake (VO2max) with WM fiber integrity and neurocognitive performance in older adults with MCI.Methods: Eighty-one participants (age = 65±7 years, 43 women), including 26 cognitively normal older adults and 55 amnestic MCI patients, underwent VO2max test to measure CRF, diffusion tensor imaging (DTI) to assess WM fiber integrity, and neurocognitive assessment focused on memory and executive function. DTI data were analyzed by the tract-based spatial statistics and region-of-interest approach.Results: Cognitively normal older adults and MCI patients were not different in global WM fiber integrity and VO2max. VO2max was associated positively with DTI metrics of fractional anisotropy in ∼54% WM fiber tracts, and negatively with mean and radial diffusivities in ∼46% and ∼56% of the WM fiber tracts. The associations of VO2max with DTI metrics remained statistically significant after adjustment of age, sex, body mass index, WM lesion burden, and MCI status. The DTI metrics obtained from the area that correlated to VO2max were associated with executive function performance in MCI patients.Conclusions: Higher levels of CRF are associated with better WM fiber integrity, which in turn is correlated with better executive function performance in MCI patients. [ABSTRACT FROM AUTHOR]