258 research outputs found
Early Diagnosis and Surgical Treatment for Necrotizing Fasciitis: A Multicenter Study
No full textBackground: Necrotizing fasciitis (NF) is a group of relatively rare infections, usually caused by two or more pathogens. It affects the skin and subcutaneous tissues of lower and upper limbs, perineal area (Fournier’s gangrene), and the abdominal wall. Early diagnosis and aggressive surgical management are of high significance for the management of this potentially lethal disease. Methods: We conducted a retrospective study in patients who presented, during the last decade, at four University Surgical Departments in the area of Athens, Greece, with an admission diagnosis of NF. Demographic, clinical, and laboratory data were gathered, and the preoperative and surgical treatment, as well as the postoperative treatment was analyzed for these patients. Results: A total of 62 patients were included in the study. The mean age of patients was 63.7 (47 male patients). Advanced age (over 65 years) (P < 0.01) and female sex (P = 0.04) correlated significantly with mortality. Perineum was the mostly infected site (46.8%), followed by the lower limbs (35.5%), the upper limbs, and the axillary region (8.1%). Diabetes mellitus was the most common coexisting disease (40.3%), followed by hypertension (25.8%) and obesity (17.7%). The most common symptom was local pain and tenderness (90.3%). Septic shock occurred in eight patients (12.9%) and strongly correlated with mortality (P < 0.01). Laboratory data were used to calculate the LRINEC score of every patient retrospectively; 26 patients (41.9%) had LRINEC score under 6, 20 patients (32.3%) had LRINEC score 6–8, and 16 patients (25.8%) had LRINEC score >9. Surgical debridement was performed in all patients (mean number of repeated debridement 4.8), and in 16 cases (25.8%) the infected limb was amputated. The mean length of hospital stay was 19.7 days, and the overall mortality rate of our series was 17.7%. Conclusion: Diagnosis of NF requires high suspect among clinicians, as its clinical image is non-specific. Laboratory tests can depict the severity of the disease; therefore, they must be carefully evaluated. Urgent surgical debridement is the mainstay of treatment in all patients; the need of repetitive surgical debridement is undisputed. © Copyright © 2017 Misiakos, Bagias, Papadopoulos, Danias, Patapis, Machairas, Karatzas, Arkadopoulos, Toutouzas, Alexakis, Konstantoulakis, Zografos, Smyrniotis, Kouraklis and Machairas
Vulnerability of cities to soil moisture and groundwater droughts
No full textDue to climate change, extreme phenomena like droughts are going to be intensified. Even though droughts in agriculture have been studied, regarding urban environment their consequences are rather unexplored. Cities are susceptible to droughts and the estimation of their vulnerability is the first step for their protection. The objective of this thesis is to determine vulnerability of cities to groundwater and soil moisture droughts. Since drought is a complex phenomenon which is difficult to define, its analysis is not straightforward especially in cities. For that reason, an urban drought categorization framework is created. In the current research, two of the four drought categories were studied (groundwater and soil moisture droughts). A case study for the vulnerability calculation was chosen for Leiden, the Netherlands. Before determining its vulnerability, different techniques to identify drought exposure characteristics were investigated. More specifically, regarding deficit and duration, the following methods were used: (i) fixed, (ii) variable, (iii) moving window method, and (iv) median groundwater level as threshold for the case of groundwater droughts. Spatial analysis was performed to estimate the areal extent of droughts whereas frequency distribution analysis is assessed of the minima of monthly blocks. A similar approach was applied for soil moisture droughts. Soil moisture is modeled via the lumped Urban Water Balance Model. Vulnerability was estimated as the aggregation of exposure and sensitivity (physical and social). For both components of vulnerability, their indicators were normalized. Out of the four drought characteristics (deficit, duration, spatial extent, and frequency), only the two first were included as exposure indicators for the vulnerability estimation. The indicators' weights were computed using the Analytical Hierarchy Process (AHP). Vulnerability estimation was applied for both groundwater and soil moisture droughts separately. One of the main results is that variable threshold performance is higher than fixed threshold and moving window for deficit and duration estimation regarding groundwater droughts. However, a combination of fixed and variable threshold can provide a profound insight into drought exposure. That applies to soil moisture droughts too. To increase performance of deficit and duration identification, pooling can be applied. An inter-event time of around 10 days for the case of variable threshold and 30th percentile is suggested regarding groundwater droughts. The analysis on soil moisture droughts was not sufficient to draw conclusions regarding inter-event time. Vulnerability follows sensitivity patterns - rather than exposure pattern - for both groundwater and soil moisture droughts at both fine and coarse space resolution. Besides, out of all indicators used, those which contribute to vulnerability variation the most were determined for both studied types of droughts. Those indicators are: `land use' and `percentage of households belonging to the lowest 40% income nationwide' for groundwater droughts whereas for soil moisture ones, it is `green areas'. Another result is that the differences in vulnerability vary marginally using different techniques to identify drought events for both studied types of droughts. Therefore, even applying a sophisticated technique to identify drought events, will not lead to significant improvement regarding vulnerability estimation. All aforementioned conclusions regarding vulnerability are highly uncertain since drought experts assigned different indicators' weights; the convergence of opinions was low. Based on the proposed methodology, water managers would be able to determine vulnerability of cities to droughts and policy makers would be able to protect the regions which are highly vulnerable. Consequently, the adverse impacts of droughts on cities could be mitigated, reducing residents' hardship
Le cuivre natif et les sulfates dans certaines dolérites
No full textThe author presents metalliferous minerals, native Cu and various sulfides in dolerites.Les minéraux métalliques de certaines dolérites de France, Guyane, Venezuela et Angola sont soit du cuivre natif et de la chalcocite, soit des sulfures : blende, chalcopyrite, violarite, pyrrhotine, pyrite, néodigénite. Ces gisements sont discutés du point de vue de la texture et de la cristallisation de la roche, en rapport avec les inclusions fluides des minéraux.Machairas Georges. Le cuivre natif et les sulfates dans certaines dolérites. In: Bulletin de la Société française de Minéralogie et de Cristallographie, volume 98, 2-3, 1975. pp. 194-198
Duodenal gangliocytic paraganglioma, successfully treated by local surgical excision-a case report
No full textIntroduction Duodenal gangliocytic paragangliomas are rare neoplasms often arising in proximity to the major duodenal papilla of Vater. These neoplasms are considered to have a benign behavior with lymph node metastases being a rare phenomenon and distant metastatic disease even more so. Resection of the tumor is the only definitive therapy. Presentation of case A 67 year old male presented to a referring hospital with symptoms of fatigue and malaise. Evaluation with CT imaging revealed a 3.1 cm intraluminal mass situated grossly at the junction of the third with the fourth portion of the duodenum. The tumor was found to be situated near the ampulla of Vater and was excised through a longitudinal duodenotomy followed by myotomy of the sphincter of Oddi. Discussion Complete resection of duodenal gangliocytic paragangliomas by surgical or endoscopic means is the only potential cure. Endoscopic removal is the first option and is both safe and adequate. Ηowever, localized excision may be utilized instead in those cases in which endoscopic removal is not possible or cannot achieve negative margins. Recurrent disease after complete resection is unlikely. Conclusion Cases of duodenal gangliocytic paragangliomas are best managed with endoscopic resection. However, local surgical excision remains as a second-choice procedure. Adjuvant chemotherapy and radiotherapy are unnecessary after complete excision. © 2017 The Author
An urban drought categorization framework and the vulnerability of a lowland city to groundwater urban droughts
No full textDue to climate change, droughts will intensify in large parts of the world. Drought and its impacts on nature and agriculture have been studied thoroughly, but its effects on the urban environment is rather unexplored. But also the built environment is susceptible to droughts and estimation of its vulnerability is the first step to its protection. This article is focusing on assessing the vulnerability of a city to groundwater drought, using parts of the lowland city of Leiden, the Netherlands, as a case study. Using a new urban drought categorization framework, groundwater drought is separated from soil moisture drought, open water drought and water supply drought, as each has its own impacts. Vulnerability was estimated as the aggregation of drought exposure and damage sensitivity. Drought deficit and duration were used as exposure indicators. Both a Fixed and Variable threshold method was used to quantify these indicators. To quantify drought vulnerability weights were assessed for selected exposure and damage sensitivity indicators using an Analytical Hierarchy Process (AHP) with a small number of experts. Based on these weights the spatial variation in vulnerability for groundwater drought follows damage sensitivity patterns—rather than exposure ones. And, out of all damage sensitivity indicators used, ‘land use', ‘low income' and ‘monuments’ contributed the most to the spatial variation in vulnerability. Due to the fact that the number of drought experts’ opinions in the AHP was limited these vulnerability results however remain uncertain. The proposed methodology however allows water managers to determine vulnerability of urbanized areas to groundwater drought, identify highly vulnerable areas and focus their mitigating actions.Water Resource
Narrative and stylistic structures in the Chronicle of Leontios Machairas
No full textSIGLEAvailable from British Library Document Supply Centre-DSC:D192402 / BLDSC - British Library Document Supply CentreGBUnited Kingdo
A 13.3 Gbps 9/7M Discrete Wavelet Transform for CCSDS 122.0-B-1 Image Data Compression on a Space-Grade SRAM FPGA
No full textRemote sensing is recognized as a cornerstone monitoring technology. The latest high-resolution and high-speed spaceborne imagers provide an explosive growth in data volume and instrument data rates in the range of several Gbps. This competes with the limited on-board storage resources and downlink bandwidth, making image data compression a mission-critical on-board processing task. The Consultative Committee for Space Data Systems (CCSDS) Image Data Compression (IDC) standard CCSDS-122.0-B-1 is a transform-based 2D image compression algorithm designed specifically for use on-board a space platform. In this paper, we introduce a high-performance architecture for a key-part of the CCSDS-IDC algorithm, the 9/7M Integer Discrete Wavelet Transform (DWT). The proposed parallel architecture achieves 2 samples/cycle while the very deep pipeline enables very high clock frequencies. Moreover, it exploits elastic pipeline principles to provide modularity, latency insensitivity and distributed control. The implementation of the proposed architecture on a Xilinx Kintex Ultrascale XQRKU060 space-grade SRAM FPGA achieves state-of-the-art throughput performance of 831 MSamples/s (13.3 Gbps @ 16bpp) allowing seamless integration with next-generation high-speed imagers and on-board data handling networking technology. To the best of our knowledge, this is the fastest implementation of the 9/7M Integer DWT on a space-grade FPGA, outperforming previous implementations
Comparing High- and Low-Model for End-Stage Liver Disease Living-Donor Liver Transplantation to Determine Clinical Efficacy: A Systematic Review and Meta-Analysis (CHALICE Study)
No full textIntroduction: Various studies have demonstrated that low-Model for End-Stage Liver Disease (MELD) living-donor liver transplant (LDLT) recipients have better outcomes with improved patient survival than deceased-donor liver transplantation (DDLT) recipients. LDLT recipients gain the most from being transplanted at MELD <25-30; however, some existing data have outlined that LDLT may provide equivalent outcomes in high-MELD and low-MELD patients, although the term "high" MELD is arbitrarily defined in the literature and various cut-off scores are outlined between 20 and 30, although most commonly, the dividing threshold is 25. The aim of this meta-analysis was to compare LDLT in high-MELD with that in low-MELD recipients to determine patient survival and graft survival, as well as perioperative and postoperative complications. Methods: Following PROSPERO registration CRD-42021261501, a systematic database search was conducted for the published literature between 1990 and 2021 and yielded a total of 10 studies with 2183 LT recipients; 490 were HM-LDLT recipients and 1693 were LM-LDLT recipients. Results: Both groups had comparable mortality at 1, 3 and 5 years post-transplant (5-year HR 1.19; 95% CI 0.79-1.79; p-value 0.40) and graft survival (HR 1.08; 95% CI 0.72, 1.63; p-value 0.71). No differences were observed in the rates of major morbidity, hepatic artery thrombosis, biliary complications, intra-abdominal bleeding, wound infection and rejection; however, the HM-LDLT group had higher risk for pulmonary infection, abdominal fluid collection and prolonged ICU stay. Conclusions: The high-MELD LDLT group had similar patient and graft survival and morbidities to the low-MELD LDLT group, despite being at higher risk for pulmonary infection, abdominal fluid collection and prolonged ICU stay. The data, primarily sourced from high-volume Asian centers, underscore the feasibility of living donations for liver allografts in high-MELD patients. Given the rising demand for liver allografts, it is sensible to incorporate these insights into U.S. transplant practices
Expression of Tissue IGF 1, TGF beta and EGFR in the Sequential Steps of Intestinal Adaptation in a Rat Model of Short Bowel Syndrome
No full textBackground : The long-term morphological changes and the expression of tissue growth factors IGF 1, TGF beta and EGFR in the gut mucosa, during the process of intestinal adaptation were examined. Methods : Four groups of rats were used : a. Sham rats (n = 10) underwent bowel transection and reanastomosis, b. SBS rats underwent an 80% small bowel resection : group A rats (n = 10) were sacrificed 15 days after surgery, group B (n = 10), 30 days after surgery, and group C (n = 10), 60 days after surgery. Morphological small bowel parameters (villus height, lumen diameter and others) of adaptation were examined sequentially. Tissue samples were studied immunohistochemically for the detection of IGF 1, TGF beta, and EGFR. Results : There was a significant increase in all morphological parameters at day 15, in the intestinal samples ; a further increase followed at day 30 and day 60 (p < 0.0001). Accordingly, an increase in the expression of IGF 1, TGF beta and EGFR was noted at day 15 (p < 0.05), and at day 30 (NS). Conclusion : Intestinal adaptation is an ongoing process lasting more than 2 months after massive small bowel resection. Peptide growth factors are expressed in the intestine continuously during this period, but the first two weeks are the most critical for the mucosal growth
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