431 research outputs found
Laparoscopic Nephroureterectomy: The Distal Ureteral Dilemma
Transitional cell carcinoma affecting the upper urinary tract, though uncommon, constitutes a serious urologic disease. Radical nephroureterectomy remains the treatment of choice but has undergone numerous modifications over the years. Although the standard technique has not been defined, the laparoscopic approach has gained in popularity in the last two decades. The most appropriate oncological management of the distal ureteral and bladder cuff has been a subject of much debate. The aim of the nephroureterectomy procedure is to remove the entire ipsilateral upper tract in continuity while avoiding extravesical transfer of tumor-containing urine during bladder surgery. A myriad of technical modifications have been described. In this article, we review the literature and present an overview of the options for dealing with the lower ureter during radical nephroureterectomy
Quantum secret sharing with qudit graph states
We present a unified formalism for threshold quantum secret sharing using
graph states of systems with prime dimension. We construct protocols for three
varieties of secret sharing: with classical and quantum secrets shared between
parties over both classical and quantum channels.Comment: 13 pages, 12 figures. v2: Corrected to reflect imperfections of (n,n)
QQ protocol. Also changed notation from to , corrected typos,
updated references, shortened introduction. v3: Updated acknowledgement
Numerical Study of Bottleneck Flow with Varying Corridor Width and Motivation Using a Speed-Based Model
In this study a simple speed-based model is employed to simulate an experiment of pedestrian bottleneck flow. The experiment revealed that the density near the bottleneck is influenced by the motivation of the pedestrians and the corridor width. In narrow corridors, distinct lanes are formed for pedestrians with low motivation. These lanes can disappear when the pedestrians have a high motivation to reach their target. We show that a speed-based model is - despite its relative simplicity- capable to reproduce the observed phenomena to a high degree
Solving the Kidney Exchange Problem Using Privacy-Preserving Integer Programming (Updated and Extended Version)
The kidney exchange problem (KEP) is to find a constellation of exchanges
that maximizes the number of transplants that can be carried out for a set of
pairs of patients with kidney disease and their incompatible donors. Recently,
this problem has been tackled from a privacy perspective in order to protect
the sensitive medical data of patients and donors and to decrease the potential
for manipulation of the computing of the exchanges. However, the proposed
approaches to date either only compute an approximative solution to the KEP or
they suffer from a huge decrease in performance. In this paper, we suggest a
novel privacy-preserving protocol that computes an exact solution to the KEP
and significantly outperforms the other existing exact approaches. Our novel
protocol is based on Integer Programming which is the most efficient method for
solving the KEP in the non privacy-preserving case. We achieve an improved
performance compared to the privacy-preserving approaches known to date by
extending the output of the ideal functionality to include the termination
decisions of the underlying algorithm. We implement our protocol in the SMPC
benchmarking framework MP-SPDZ and compare its performance to the existing
protocols for solving the KEP. In this extended version of our paper, we also
evaluate whether and if so how much information can be inferred from the
extended output of the ideal functionality.Comment: This is the updated and extended version of the work published in
19th Annual International Conference on Privacy, Security and Trust
(PST2022), August 22-24, 2022, Fredericton, Canada / Virtual Conference,
https://doi.org/10.1109/PST55820.2022.985196
On the Observation of Vacuum Birefringence
We suggest an experiment to observe vacuum birefringence induced by intense
laser fields. A high-intensity laser pulse is focused to ultra-relativistic
intensity and polarizes the vacuum which then acts like a birefringent medium.
The latter is probed by a linearly polarized x-ray pulse. We calculate the
resulting ellipticity signal within strong-field QED assuming Gaussian beams.
The laser technology required for detecting the signal will be available within
the next three years.Comment: 4 pages, 4 figure
Randomized controlled trials of antibiotic prophylaxis in severe acute pancreatitis:Relationship between methodological quality and outcome
AIM: To evaluate the methodological quality of randomized controlled trials (RCTs) of systemic antibiotic prophylaxis in severe acute pancreatitis in relation to outcome. METHODS: The MEDLINE, EMBASE and Cochrane databases were searched for RCTs that studied the effectiveness of systemic antibiotic prophylaxis in severe acute pancreatitis. A meta-analysis was performed with a random effects model. Methodological quality was quantified by a previously published scoring system (range 0-17 points). RESULTS: Six studies, with a total of 397 participants, obtained a methodological score of at least 5 points and were included. Systemic antibiotic prophylaxis had no significant effect on infection of pancreatic necrosis (absolute risk reduction (ARR) 0.055; 95% CI -0.084 to 0.194) and mortality (ARR 0.058, 95% CI -0.017 to 0.134). Spearman correlation showed an inverse association between methodological quality and ARR for mortality (correlation coefficient -0.841, p = 0.036). CONCLUSIONS: The inverse relationship between methodological quality and impact of antibiotic prophylaxis on mortality emphasizes the importance of high-quality RCTs. At present, adequate evidence for the routine use of antibiotic prophylaxis in severe acute pancreatitis is lackin
Glycosphingolipids are required for sorting melanosomal proteins in the Golgi complex
A;lthough glycosphingolipids are ubiquitously expressed and essential for multicellular organisms, surprisingly little is known about their intracellular functions. To explore the role of glycosphingolipids in membrane transport, we used the glycosphingolipid-deficient GM95 mouse melanoma cell line. We found that GM95 cells do not make melanin pigment because tyrosinase, the first and rate-limiting enzyme in melanin synthesis, was not targeted to melanosomes but accumulated in the Golgi complex. However, tyrosinase-related protein 1 still reached melanosomal structures via the plasma membrane instead of the direct pathway from the Golgi. Delivery of lysosomal enzymes from the Golgi complex to endosomes was normal, suggesting that this pathway is not affected by the absence of glycosphingolipids. Loss of pigmentation was due to tyrosinase mislocalization, since transfection of tyrosinase with an extended transmembrane domain, which bypassed the transport block, restored pigmentation. Transfection of ceramide glucosyltransferase or addition of glucosylsphingosine restored tyrosinase transport and pigmentation. We conclude that protein transport from Golgi to melanosomes via the direct pathway requires glycosphingolipids
Fryer control strategy improvement:towards acrylamide reduction in crisp manufacture
This paper describes research efforts to improve the operation of industrial scale crisp fryers to ensure that product quality targets are exceeded. The work described was undertaken within a project whose aim is to minimise the acrylamide formation arising during processing operations. The existing fryer temperature control scheme was found to be sub-optimal from an acrylamide perspective and involved considerable operator intervention, particularly at fryer start-up. A new temperature control system was designed and implemented to overcome the shortcomings of the existing strategy. Fryer temperature and crisp moisture were regulated effectively through gas flow and dwell time modifications. Interactions between loops were compensated for and start-up was automated to reduce the impact of operator-to-operator variation. The resulting scheme was found to deliver much-improved temperature control which will lead to a resultant decrease in acrylamide formation
Effect of Revascularization on Intramuscular Vascular Endothelial Growth Factor Levels in Peripheral Arterial Disease
Vascular endothelial growth factor (VEGF) is a potent driver of angiogenesis, which may help to relieve ischemia in peripheral arterial disease (PAD). We aimed to investigate the role of intramuscular VEGF in ischemic and non-ischemic skeletal muscle in PAD patients before and after surgical or endovascular revascularization and different stages of PAD. Biopsies of the gastrocnemius and vastus muscles from twenty PAD patients with stenosis or occlusion of the superficial femoral artery were obtained both during revascularization and 8 weeks postoperatively. The gastrocnemius muscle was considered ischemic, while vastus muscle biopsies served as intraindividual controls. The levels of vascular endothelial growth factor in muscle lysates were then determined by ELISA. Preoperative VEGF levels were significantly higher in ischemic muscles compared to the controls (98.07 ± 61.96 pg/mL vs. 55.50 ± 27.33 pg/mL, p = 0.004). Postoperative values decreased significantly (p = 0.010) to 54.83 ± 49.60 pg/mL in gastrocnemius biopsies. No significant change was observed in vastus muscle biopsies, with mean postoperative VEGF values found at 54.16 ± 40.66 pg/mL. Since all patients still had indications for revascularization, impairment of angiogenesis mechanisms can be assumed. More research about angiogenesis in PAD is needed with the ultimate goal to improve conservative treatment
Operational considerations for hot-washing in potato crisp manufacture
As part of an overall programme aimed at reducing the acrylamide content of crisps, this paper explores the impact of hot-washing on potato slice sugar concentration during industrial scale manufacture. We investigated cold-washing as an alternative to hot-washing, hot-wash residence time and temperature to optimise sugar removal and therefore reduce the potential for high acrylamide levels after frying. Due to the variable nature of potatoes, an extensive variability study was performed to determine confidence boundaries of results. It was found that the cold-wash unit removed on average 21% of the initial sugar content. In the hot-wash the current operational residence time of 3.5 minutes at 70oC gave a sugar reduction of 27.5%, which could be increased to 48.5% if residence time is extended to 5 minutes. Hot-wash temperatures of 40oC - 60oC were found to increase glucose and fructose content and therefore the potential for acrylamide formation. A “double cold-wash” was trialled and proved to be as successful as hot-washing at 70oC for all but the highest sugar potatoes, challenging the current operational process and offering the potential for major energy savings
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