A Novel Classification System to Address Financial Impact and Referral Decisions for Bile Duct Injury in Laparoscopic Cholecystectomy

Purpose. The study was undertaken to evaluate a novel classification system developed to estimate financial cost of bile duct injury (BDI) and to aid in decision making for referral. Study Design. A retrospective review of patients referred for BDI was performed. Grade I injuries involve the duct of Luschka or accessory right hepatic ducts, grade II includes all other biliary injuries, and grade III includes all vasculobiliary injuries. Groups were compared using standard statistical methods. Results. There were 14 grade I, 74 grade II, and 20 grade III injuries. There was a significant difference in the cost and mortality of grade I ($12,457, 0$46,481, 1.4%), and grade III ($69,368, 15%, P = 0.002 and P = 0.030, resp.) injuries. Grade II and III injuries were significantly more likely to require surgical repair (OR 27.7, P < 0.001). Conclusion. We have presented a simple classification system that is able to accurately predict cost and need for surgical repair

Surgical resection for hilar cholangiocarcinoma: experience improves resectability

AbstractObjectivesIn hilar cholangiocarcinoma, resection provides the only opportunity for longterm survival. A US experience of hilar cholangiocarcinoma was examined to determine the effect of clinical experience on negative margin (R0) resection rates.MethodsWe conducted a retrospective analysis of 110 consecutive hilar cholangiocarcinoma patients presenting over an 18-year period. Analyses were performed using chi-squared, Wilcoxon rank sum and Kaplan–Meier methods, and multivariable Cox and logistic regression modelling.ResultsOf the 110 patients in the cohort, 59.1% were male and 90.9% were White. The median patient age was 64 years. A total of 59 (53.6%) patients underwent resection; 37 of these demonstrated R0. The 30-day mortality rate was 5.1%; the complication rate was 39.0%. The rate of resectability increased over time (36.4% vs. 70.9%; P= 0.001), as did the percentage of R0 resections (10.9% vs. 56.5%; P < 0.001). Of the 59 patients who underwent resection, 23 (39.0%) experienced recurrence. Multivariable Cox regression analysis identified resection margins [hazard ratio (HR) = 4.124 for positive vs. negative; P= 0.002] and type of operation (HR = 5.075 for exploration vs. resection; P= 0.001) as significant to survival.ConclusionsAlthough R0 resection can be achieved in only a minority of patients, these patients have a reasonable chance of longterm survival. The last decade has seen a significant rise in rates of resectability of Klatskin's tumour at specialty centres

Analysis and Observations from the First Amazon Picking Challenge

This paper presents a overview of the inaugural Amazon Picking Challenge along with a summary of a survey conducted among the 26 participating teams. The challenge goal was to design an autonomous robot to pick items from a warehouse shelf. This task is currently performed by human workers, and there is hope that robots can someday help increase efficiency and throughput while lowering cost. We report on a 28-question survey posed to the teams to learn about each team's background, mechanism design, perception apparatus, planning and control approach. We identify trends in this data, correlate it with each team's success in the competition, and discuss observations and lessons learned based on survey results and the authors' personal experiences during the challenge

Micro-scale Artificial Weave Generation Capabilities for Thermal Protection System Material Modeling

Thermal Protection System (TPS) modeling requires accurate representation and prediction of the thermomechanical behavior of ablative materials. State-of-the-art TPS materials such as Phenolic Impregnated Carbon Ablator (PICA) have a proven flight record and demonstrate exceptional capabilities for handling extreme aerothermal heating conditions. The constant push for lightweight materials that are flexible in their design and performance, and hence allow for a wide range of mission profiles, has led NASA over the past years to develop its Heatshield for Extreme Entry Environment Technology (HEEET). HEEET is based primarily on a dual layer woven carbon fiber architecture and the technology has successfully been tested in arc-jet facilities. These recent developments have sparked interest in the accurate micro-scale modeling of composite weave architectures, to predict the structural response of macro-scale heatshields upon atmospheric entry. This effort can be extended to incorporate in-depth failure mechanics analyses as a result of local thermal gradients or high-velocity particle impact

Free-Flight Trajectory Simulation of the ADEPT Sounding Rocket Test Using CFD

A computational study of the Adaptive Deployable Entry and Placement Technology (ADEPT) Sounding Rocket (SR-1) Test is presented using the US3D flow solver. ADEPT SR-1 is intended, in part, to assess the dynamic stability of this entry vehicle architecture. Given that no dynamic stability data exists for the ADEPT geometry, a limited ballistic range campaign has been performed to characterize the vehicle's stability characteristics pre-flight for Mach numbers between 1.21 and 2.5. Here, this data is used to assess the accuracy of US3D's free-flight CFD capability. Computed trajectories from US3D and experimental data show that the flow solver compares well in vehicle oscillation frequency, downrange distance, and oscillatory amplitude during high Mach number flight (Mavg = 2.36). For Mach numbers below 1.5, the solver under predicts total angle-of-attack by an average of 16%, but compares well in oscillatory frequency and downrange distance. Additionally, a capability for simulating the trajectory of the flight article through the atmosphere using CFD is presented. This capability couples US3D's free-flight capability to an atmosphere model that accounts for changes in free-stream density and temperature as the vehicle descends. Two simulations for the purpose of demonstrating the capability and viability of this approach are applied to SR-1 flight article, and some unique challenges are discussed

Identification of glyceraldehyde‐3‐phosphate dehydrogenase as a Ca2+‐dependent fusogen in human neutrophil cytosol

The membrane fusion events observed during neutrophil degranulation are important aspects of the immunoregulatory system. In an attempt to understand the regulation of granule‐plasma membrane fusion, we have begun characterizing human neutrophil cytosol for fusion activity, finding that 50% of the fusogenic activity could be attributed to members of the annexin family of proteins. The major non‐annexin fusion activity (25% of the total cytosolic activity) was enriched by ion exchange chromatography after depletion of annexins by Ca2+‐dependent phospholipid affinity chromatography. The fusion activity co‐purified with a 10,14‐kDa dimer identified as leukocyte L1 (which was non‐fusogenic), along with an approximately 36‐kDa protein. This protein was identified as glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH) by amino‐terminal sequencing, and the fusion activity was verified using commercially available GAPDH. GAPDH may play an important role in degranulation because it is as potent as annexin I on a mass basis and may constitute up to 25% of the total cytosolic fusion activity of the neutrophil. J. Leukoc. Biol. 63: 331–336; 1998.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142089/1/jlb0331.pd

Accelerating Bayesian hierarchical clustering of time series data with a randomised algorithm

We live in an era of abundant data. This has necessitated the development of new and innovative statistical algorithms to get the most from experimental data. For example, faster algorithms make practical the analysis of larger genomic data sets, allowing us to extend the utility of cutting-edge statistical methods. We present a randomised algorithm that accelerates the clustering of time series data using the Bayesian Hierarchical Clustering (BHC) statistical method. BHC is a general method for clustering any discretely sampled time series data. In this paper we focus on a particular application to microarray gene expression data. We define and analyse the randomised algorithm, before presenting results on both synthetic and real biological data sets. We show that the randomised algorithm leads to substantial gains in speed with minimal loss in clustering quality. The randomised time series BHC algorithm is available as part of the R package BHC, which is available for download from Bioconductor (version 2.10 and above) via http://bioconductor.org/packages/2.10/bioc/html/BHC.html. We have also made available a set of R scripts which can be used to reproduce the analyses carried out in this paper. These are available from the following URL. https://sites.google.com/site/randomisedbhc/

UK Housing Market: Time Series Processes with Independent and Identically Distributed Residuals

The paper examines whether a univariate data generating process can be identified which explains the data by having residuals that are independent and identically distributed, as verified by the BDS test. The stationary first differenced natural log quarterly house price index is regressed, initially with a constant variance and then with a conditional variance. The only regression function that produces independent and identically distributed standardised residuals is a mean process based on a pure random walk format with Exponential GARCH in mean for the conditional variance. There is an indication of an asymmetric volatility feedback effect but higher frequency data is required to confirm this. There could be scope for forecasting the index but this is tempered by the reduction in the power of the BDS test if there is a non-linear conditional variance process

Posterior lung herniation after a coughing spell: a case report

Lung hernias are rare, occurring most commonly after trauma or surgery. Spontaneous lung hernias are even rarer and have only been reported as occurring anteriorly. We present a 72-year-old male who developed a spontaneous posterior lung hernia after a severe coughing episode. We describe the evaluation and surgical management of this unusual condition and provide a brief review of the literature

Crystal structure of the Na+/H+ antiporter NhaA at active pH reveals the mechanistic basis for pH sensing.

The strict exchange of protons for sodium ions across cell membranes by Na+/H+ exchangers is a fundamental mechanism for cell homeostasis. At active pH, Na+/H+ exchange can be modelled as competition between H+ and Na+ to an ion-binding site, harbouring either one or two aspartic-acid residues. Nevertheless, extensive analysis on the model Na+/H+ antiporter NhaA from Escherichia coli, has shown that residues on the cytoplasmic surface, termed the pH sensor, shifts the pH at which NhaA becomes active. It was unclear how to incorporate the pH senor model into an alternating-access mechanism based on the NhaA structure at inactive pH 4. Here, we report the crystal structure of NhaA at active pH 6.5, and to an improved resolution of 2.2 Å. We show that at pH 6.5, residues in the pH sensor rearrange to form new salt-bridge interactions involving key histidine residues that widen the inward-facing cavity. What we now refer to as a pH gate, triggers a conformational change that enables water and Na+ to access the ion-binding site, as supported by molecular dynamics (MD) simulations. Our work highlights a unique, channel-like switch prior to substrate translocation in a secondary-active transporter