Mortality, Reamputation, and Preoperative Comorbidities in Patients Undergoing Dysvascular Lower Limb Amputation

Background: Historically, mortality rates after major lower limb amputations (LLAs) have been very high. However, there are inconsistencies regarding the risk factors. The reamputation rate after major LLAs is largely unknown. The aim of this study is to report the 30-day and 1-year mortality and 1-year reamputation rates after major LLA and to identify potential risk factors.Methods: An observational cohort study in which all patients undergoing dysvascular major LLA in 2012-2013 in 12 hospitals in the northern region of the Netherlands is included.Results: Of total 382 patients, who underwent major LLA, 65% were male and the mean age (standard deviation [SD]) was 71.9 +/- 12.5 years. Peripheral arterial disease was observed in 88% and diabetes mellitus (DM), in 56% of patients. No revascularization or prior LLA on the amputated side was observed among 26%, whereas 56% had no minor or major LLA on either limb before the study period. The 30-day and 1-year mortality rates were 14% and 34%, respectively. Patients aged 75-84 and &gt;85 years had 3-4 times higher odds of dying within 1 year. Transfemoral amputations (odds ratio [OR], 2.2), history of heart failure (OR, 2.3), myocardial infarction (OR, 1.7), hemodialysis (OR, 5.7), immunosuppressive medication (OR, 2.8), and guillotine amputations (OR, 5.1) were independently associated with 1-year mortality. Twenty-six percent underwent ipsilateral reamputation within 1 year, for which no risk factors were identified.Conclusions: The mortality rate in the first year after major LLA is high, particularly among those undergoing transfemoral amputations, which is likely to be indicative of more severe vascular disease. Higher mortality among the most elderly patients, those with more severe cardiac disease and who underwent hemodialysis reflects the frailty of this population. Interestingly, DM, revascularization history, and prior minor or major LLA were not associated with mortality rates.</p

On the response to hygrothermal aging of pultruded FRPs used in the civil engineering sector

This paper presents the effects of hygrothermal aging on the durability of a pultruded flat sheet, immersed in distilled water at 25oC, 40oC, 60oC or 80oC for a period of 224 days. Elevated temperatures noticeably increase the moisture diffusion coefficient and moisture uptake behaviour. Measured changes in the tensile and in-plane shear mechanical properties were examined after 28, 56, 112 or 224 days. Tensile properties remained practically unaffected by aging whereas matrix dominated shear properties revealed an initial drop which was recovered to a substantial degree after further hygrothermal aging. Visco-elastic property changes due to the superimposing mechanisms of plasticization, additional cross-linking etc. were recorded. Scanning Electron Microscopy micrographs indicate that the fibre/matrix interface remained practically intact, even after the most aggressive hot/wet aging. X-Ray Energy Dispersive Spectroscopy analysis showed no chemical degradation incidents on the fibre reinforcement surfaces and infrared spectroscopy revealed superficial chemical alteration in the aging matrix. Optical microscopy revealed matrix cracking in samples aged at 80oC for 112 days. Lastly, Computed Tomography scans of un-aged material showed internal imperfections that undoubtedly enhanced moisture transport. After aging at 60oC for 112 days, Computed Tomography detected preferentially situated water pockets

Ruppeiner Geometry of Anyon Gas

We derive the thermodynamic curvature of a two dimensional ideal anyon gas of particles obeying fractional statistics. The statistical interactions of anyon gas can be attractive or repulsive. For attractive statistical interactions, thermodynamic curvature is positive and for repulsive statistical interactions, it is negative, which indicates a more stable anyon gas. There is a special case between the two where the thermodynamic curvature is zero. Small deviations from the classical limit will also be explored.Comment: 12 page

Shape-Based Separation of Micro-/Nanoparticles in Liquid Phases

The production of particles with shape-specific properties is reliant upon the separation of micro-/nanoparticles of particular shapes from particle mixtures of similar volumes. However, compared to a large number of size-based particle separation methods, shape-based separation methods have not been adequately explored. We review various up-to-date approaches to shape-based separation of rigid micro-/nanoparticles in liquid phases including size exclusion chromatography, field flow fractionation, deterministic lateral displacement, inertial focusing, electrophoresis, magnetophoresis, self-assembly precipitation, and centrifugation. We discuss separation mechanisms by classifying them as either changes in surface interactions or extensions of size-based separation. The latter includes geometric restrictions and shape-dependent transport properties

Constrained and unconstrained rearrangement minimization problems related to the p-Laplace operator

In this paper we consider an unconstrained and a constrained minimization problem related to the boundary value problem −∆pu = f in D, u = 0 on ∂D. In the unconstrained problem we minimize an energy functional relative to a rearrangement class, and prove existence of a unique solution. We also consider the case when D is a planar disk and show that the minimizer is radial and increasing. In the constrained problem we minimize the energy functional relative to the intersection of a rearrangement class with an affine subspace of codimension one in an appropriate function space. We briefly discuss our motivation for studying the constrained minimization problem

Existence of continuous eigenvalues for a class of parametric problems involving the (p,2)-laplacian operator

We discuss a parametric eigenvalue problem, where the differential operator is of (p,2)-Laplacian type. We show that, when p≠2, the spectrum of the operator is a half line, with the end point formulated in terms of the parameter and the principal eigenvalue of the Laplacian with zero Dirichlet boundary conditions. Two cases are considered corresponding to p>2 and p2, and to infinity in the case of p<2

Effect of tissue-harvesting site on yield of stem cells derived from adipose tissue: implications for cell-based therapies

The stromal vascular fraction (SVF) of adipose tissue contains an abundant population of multipotent adipose-tissue-derived stem cells (ASCs) that possess the capacity to differentiate into cells of the mesodermal lineage in vitro. For cell-based therapies, an advantageous approach would be to harvest these SVF cells and give them back to the patient within a single surgical procedure, thereby avoiding lengthy and costly in vitro culturing steps. However, this requires SVF-isolates to contain sufficient ASCs capable of differentiating into the desired cell lineage. We have investigated whether the yield and function of ASCs are affected by the anatomical sites most frequently used for harvesting adipose tissue: the abdomen and hip/thigh region. The frequency of ASCs in the SVF of adipose tissue from the abdomen and hip/thigh region was determined in limiting dilution and colony-forming unit (CFU) assays. The capacity of these ASCs to differentiate into the chondrogenic and osteogenic pathways was investigated by quantitative real-time polymerase chain reaction and (immuno)histochemistry. A significant difference (P = 0.0009) was seen in ASC frequency but not in the absolute number of nucleated cells between adipose tissue harvested from the abdomen (5.1 ± 1.1%, mean ± SEM) and hip/thigh region (1.2 ± 0.7%). However, within the CFUs derived from both tissues, the frequency of CFUs having osteogenic differentiation potential was the same. When cultured, homogeneous cell populations were obtained with similar growth kinetics and phenotype. No differences were detected in differentiation capacity between ASCs from both tissue-harvesting sites. We conclude that the yield of ASCs, but not the total amount of nucleated cells per volume or the ASC proliferation and differentiation capacities, are dependent on the tissue-harvesting site. The abdomen seems to be preferable to the hip/thigh region for harvesting adipose tissue, in particular when considering SVF cells for stem-cell-based therapies in one-step surgical procedures for skeletal tissue engineering

Hematogenous Metastasis of Ovarian Cancer: Rethinking Mode of Spread

SummaryOvarian cancer has a clear predilection for metastasis to the omentum, but the underlying mechanisms involved in ovarian cancer spread are not well understood. Here, we used a parabiosis model that demonstrates preferential hematogenous metastasis of ovarian cancer to the omentum. Our studies revealed that the ErbB3-neuregulin 1 (NRG1) axis is a dominant pathway responsible for hematogenous omental metastasis. Elevated levels of ErbB3 in ovarian cancer cells and NRG1 in the omentum allowed for tumor cell localization and growth in the omentum. Depletion of ErbB3 in ovarian cancer impaired omental metastasis. Our results highlight hematogenous metastasis as an important mode of ovarian cancer metastasis. These findings have implications for designing alternative strategies aimed at preventing and treating ovarian cancer metastasis

Clinical Course and Outcomes of Small Supratentorial Intracerebral Hematomas.

Intracerebral hemorrhage (ICH) volume, particularly if ≥30 mL, is a major determinant of poor outcome. We used a multinational ICH data registry to study the characteristics, course, and outcomes of supratentorial hematomas with volumes <30 mL.Basic characteristics, clinical and radiological course, and 30-day outcomes of these patients were recorded. Outcomes were categorized as early neurological deterioration (END), hematoma expansion, Glasgow Outcome Scale (GOS), and in-hospital death. Poor outcome was defined as composite of in-hospital death and severe disability (GOS ≤ 3). Comparison was conducted based on hemorrhage location. Logistic regression using dichotomized outcome scales was applied to determine predictors of poor outcome.Among 375 cases of supratentorial ICH with volumes <30 mL, expansion and END rates were 19.2% and 7.5%, respectively. Hemorrhage growth was independently associated with END (odds ratio: 28.7, 95% confidence interval [CI]: 8.51-96.5; P < .0001). Expansion rates did not differ according to ICH location. Overall, 13.9% (exact binomial 95% CI: 10.5-17.8) died in the hospital and 29.1% (CI: 24.5-34.0) had severe disability at 30 days; there was a cumulative poor outcome rate of 42.9% (CI: 37.9-48.1). Age, admission Glasgow Coma Scale, intraventricular extension, and END were independently associated with poor outcome. There was no difference in poor outcome rates between lobar and deep locations (40.2% versus 43.8%, P = .56).Patients with supratentorial ICH <30 mL have high rates of poor outcome at 30 days, regardless of location. Nearly 1 in 5 hematomas <30 mL expands, leading to END or death