2,874 research outputs found
Surgical management of peritonitis secondary to acute superior mesenteric artery occlusion.
Diagnosis of acute arterial mesenteric ischemia in the early stages is now possible using modern computed tomography with intravenous contrast enhancement and imaging in the arterial and/or portal phase. Most patients have acute superior mesenteric artery (SMA) occlusion, and a large proportion of these patients will develop peritonitis prior to mesenteric revascularization, and explorative laparotomy will therefore be necessary to evaluate the extent and severity of intestinal ischemia, and to perform bowel resections. The establishment of a hybrid operating room in vascular units in hospitals is most important to be able to perform successful intestinal revascularization. This review outlines current frontline surgical strategies to improve survival and minimize bowel morbidity in patients with peritonitis secondary to acute SMA occlusion. Explorative laparotomy needs to be performed first. Curative treatment is based upon intestinal revascularization followed by bowel resection. If no vascular imaging has been carried out, SMA angiography is performed. In case of embolic occlusion of the SMA, open embolectomy is performed followed by angiography. In case of thrombotic occlusion, the occlusive lesion can be recanalized retrograde from an exposed SMA, the guidewire snared from either the femoral or brachial artery, and stented with standard devices from these access sites. Bowel resections and sometimes gall bladder removal due to transmural infarctions are performed at initial laparotomy, leaving definitive bowel reconstructions to a planned second look laparotomy, according to the principles of damage control surgery. Patients with peritonitis secondary to acute SMA occlusion should be managed by both the general and vascular surgeon, and a hybrid revascularization approach is of utmost importance to improve outcomes
Vacuum-assisted wound closure versus alginate for the treatment of deep perivascular wound infections in the groin after vascular surgery
BackgroundVacuum-assisted wound closure (VAC) therapy may heal wounds faster than conventional dressings after surgical debridement of perivascular groin infections after vascular surgery.MethodsPatients with deep infected wounds (Szilagyi grade III) were surgically revised and left open for secondary healing, then randomized to either VAC or alginate (Sorbalgon) therapy, between February 2007 and November 2011. To test the hypothesis, it was calculated that 42 patients needed to be included (90% power, 5% level of significance). It was decided to perform an interim analysis after inclusion of 20 patients.ResultsAmong 66 patients undergoing groin revision, 20 patients were included in this study. Patients were randomized to VAC (n = 10) or alginate (n = 10). The two groups were comparable in patient and wound characteristics. Time to full skin epithelialization was significantly shorter in the VAC group (median, 57 days) compared with the alginate group (median, 104 days; P = .026). The number of positive wound cultures of bacteria and C-reactive protein values decreased equally in both groups between surgical revision and day 21. One femur amputation was performed in each group as a consequence of the groin infection, one patient died during the in-hospital stay in the alginate group, and none died in the VAC group.ConclusionsVAC achieves faster healing than alginate therapy after wound debridement for deep perivascular wound infections in the groin after vascular surgery. This finding does not allow further inclusion of patients from an ethical point of view, and this study was, therefore, stopped prematurely
Robust Maneuvering Envelope Estimation Based on Reachability Analysis in an Optimal Control Formulation
This paper discusses an algorithm for estimating the safe maneuvering envelope of damaged aircraft. The algorithm performs a robust reachability analysis through an optimal control formulation while making use of time scale separation and taking into account uncertainties in the aerodynamic derivatives. Starting with an optimal control formulation, the optimization problem can be rewritten as a Hamilton- Jacobi-Bellman equation. This equation can be solved by level set methods. This approach has been applied on an aircraft example involving structural airframe damage. Monte Carlo validation tests have confirmed that this approach is successful in estimating the safe maneuvering envelope for damaged aircraft
Forensic assessment of single stab injuries to the trunk
IntroductionForensic pathologists are frequently confronted with questions about the likelihood that an injury is inflicted by an assault or is self-inflicted. However, little is known of epidemiological variables applicable to differentiate between homicides and suicides in deaths caused by single stab injuries to the trunk. MethodUsing the Swedish forensic autopsy register we identified 94 homicides and 45 suicides between 2010 and 2021 that died following a single stab injury to the trunk. We extracted characteristics from the cases and performed statistical analyses using Mann-Whitney U and Chi-square test.ResultVictims of homicides were younger than suicide victims (median age 33 years vs. 52 years, p < 0.05), and males were in majority in both groups (93% vs. 82%). Some homicidal stab wounds were placed on the posterior (12%) and axillar trunk (11%) unlike the suicidal stabs which were all placed on the anterior trunk. Most stab wounds of all examinations were placed on the left side of the anterior thorax (60%). In suicides, single stab injuries to the heart were more common than in homicides (67% vs. 48%, p < 0.05). Vasculature injuries were more common in homicides (51% vs. 9%, p < 0.05).DiscussionThe epidemiological variables could be used as a tool when assessing the manner of death in single stabs. Further research on variables associated with manner of death are needed and we suggest also including surviving victims in such analyses
Low plasma triiodothyronine levels in heart failure are associated with a reduced anabolic state and membrane damage
BACKGROUND: Low plasma triiodothyronine (T(3)) levels are considered a prognostic predictor of death in heart failure (HF) patients. AIM: To study an association between plasma T(3) levels and several cardiac, neurohormonal, and metabolic markers of HF. METHODS: A total of 133 ambulatory HF patients (114 males; mean age 63.2 years) with left ventricular ejection fraction <40% were enrolled. TSH, total tetraiodothyronine (T(4)) and T(3), N-terminal pro-brain natriuretic peptide (NT-proBNP), and other cardiac and metabolic parameters were measured. The lowest tertile of T(3) (group 1) was compared against the two upper ones (group 2). RESULTS: In simple logistic regression, the lowest T(3) tertile was associated with more advanced HF disease status: older (age: odds ratio (OR)=1.05; confidence interval (CI) 95% 1.01-1.09, P=0.004), lower functional capacity (walking test: OR=0.996; CI 95% 0.993-0.999, P=0.008), higher NT-proBNP (OR=1.64; CI 95% 1.19-2.27, P=0.003) and adiponectin levels (OR=1.07; CI 95% 1.02-1.11, P=0.004), lower DHEAS log-transformed (OR=0.50; CI 95% 0.31-0.80, P=0.004), and the presence of lower phase angle values as measured by body bioelectrical impedance analysis (OR=3.18; CI 95% 1.50-6.71, P=0.04) and worse renal function (OR=0.96; CI 95% 0.94-0.98, P=0.003). T(3) levels in the lowest tertile were independently associated with low phase angle values (OR=2.95, CI 95% 1.16-7.50, P=0.02) and the log transformation of DHEAS (OR=0.56; CI 95% 0.32-0.97, P=0.04). CONCLUSION: We have demonstrated an association between plasma T(3) levels in the lower range and other deranged hormonal and metabolic parameters in HF patients.Fil: Brenta, Gabriela. Gobierno de la Ciudad de Buenos Aires. Hospital CĂ©sar Milstein; ArgentinaFil: Thierer, Jorge. Instituto Cardiovascular de Buenos Aires; ArgentinaFil: Sutton, Marcela. Instituto Cardiovascular de Buenos Aires; ArgentinaFil: Acosta, Adriana. Instituto Cardiovascular de Buenos Aires; ArgentinaFil: Vainstein, Nora. Instituto Cardiovascular de Buenos Aires; ArgentinaFil: Brites, Fernando Daniel. Universidad de Buenos Aires. Facultad de Farmacia y BioquĂmica; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Boero, Laura. Universidad de Buenos Aires. Facultad de Farmacia y BioquĂmica; ArgentinaFil: Gomez Rosso, Leonardo Adrián. Universidad de Buenos Aires. Facultad de Farmacia y BioquĂmica; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Anker, Stefan. Istituto di Ricovero e Cura a Carattere Scientifico; Italia. CharitĂ© Universitätsmedizin Berlin; Alemani
An Infrastructure for Spatial Linking of Survey Data
Research on environmental justice comprises health and well-being aspects, as well as topics related to general social participation. In this research field, among others, there is a need for an integrated use of social science survey data and spatial science data, e.g. for combining demographic information from survey data with data on pollution from spatial data. However, for researchers it is challenging to link both data sources, because (1) the interdisciplinary nature of both data sources is different, (2) both underlie different legal restrictions, in particular regarding data privacy, and (3) methodological challenges arise regarding the use of geo-information systems (GIS) for the processing and analysis of spatial data.
In this article, we present an infrastructure of distributed web services which supports researchers in the process of spatial linking. The infrastructure addresses the challenges researchers have to face during that process. We present an example case study on the investigation of environmental inequalities with regards to income and land use hazards in Germany by using georeferenced survey data of the GESIS Panel and the German Socio-economic Panel (SOEP), and by using spatial data from the Monitor of Settlement and Open Space Development (IOER Monitor). The results show that increasing income of survey respondents is associated with less exposure to land-use-related environmental hazards in Germany
Assessing the Potential of Diverse Forage Mixtures to Reduce Enteric Methane Emissions In Vitro
Methane emissions from ruminants are a major contributor to agricultural greenhouse gas emissions. Thus, eight different forage species were combined in binary mixtures with Lolium perenne in increasing proportions, in vitro, to determine their methane reduction potential in ruminants. Species were sampled in two consecutive years where possible. The aims were: a) to determine if mixtures with specific forages, particularly those rich in plant specialized metabolites (PSM), can reduce methane emissions compared to ryegrass monocultures, b) to identify whether there is a linear-dose effect relationship in methane emissions from the legume or herb addition, and c) whether these effects are maintained across sampling years. Results showed that all dicot species studied, including the non-tannin-containing species, reduced methane production. The tannin-rich species, Sanguisorba minor and Lotus pedunculatus, showed the greatest methane reduction potential of up to 33%. Due to concomitant reductions in the forage digestibility, Cichorium intybus yielded the lowest methane emissions per digestible forage unit. Contrary to total gas production, methane production was less predictable, with a tendency for the lowest methane production being obtained with a 67.5% share of the legume or herb partner species. Thus, linear increments in the partner species share did not result in linear changes in methane concentration. The methane reduction potential differed across sampling years, but the species ranking in methane concentration was stable
A Short-Time Approach for Fatigue Life Evaluation of AISI 347 Steel for Nuclear Power Energy Applications
AISI 347 austenitic steel is, as an example, used in nuclear energy piping systems. Piping
filled with superheated steam or cooled water is particularly exposed to high stresses, whereupon
local material properties in the pipes can change significantly, especially in the case of additional
corrosive influences, leading to aging of the material. In the absence of appropriate information, such
local material property variations are currently covered rather blanketly by safety factors set during
the design of those components. An increase in qualified information could improve the assessment
of the condition of such aged components. As part of the collaborative project “Microstructure-based
assessment of the maximum service life of core materials and components subjected to corrosion and
fatigue (MiBaLeB)”, the short-time procedure, StrainLife, was developed and validated by several
fatigue tests. With this procedure, a complete S–N curve of a material can be determined on the
basis of three fatigue tests only, which reduces the effort compared to a conventional approach
significantly and is thus ideal for assessing the condition of aged material, where the material is often
rare, and a cost-effective answer is often very needed. The procedure described is not just limited to
traditional parameters, such as stress and strain, considered in destructive testing but rather extends
into parameters derived from non-destructive testing, which may allow further insight into what
may be happening within a material’s microstructure. To evaluate the non-destructive quantities
measured within the StrainLife procedure and to correlate them with the aging process in a material,
several fatigue tests were performed on unnotched and notched specimens under cyclic loading at
room and elevated temperatures, as well as under various media conditions, such as distilled water
and reactor pressure vessel boiling water (BWR) conditions
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