Precipitation-based microscale enzyme reactors coupled with porous and adhesive elastomer for effective bacterial decontamination and membrane antifouling on-demand.

Bacterial contamination of water environments can cause various troubles in various areas. As one of potential solutions, we develop enzyme-immobilized elastomer, and demonstrate the uses of enzyme reactions on-demand for effective microbial decontamination and antifouling. Asymmetrically-structured elastomer is prepared by combining two polydimethylsiloxane (PDMS) layers with different degrees of crosslinking: highly-crosslinked and lightly-crosslinked PDMS layers. At the surface of highly-crosslinked PDMS layer, porous structure with average diameter of 842 nm is formed by dissolving pre-packed and entrapped latex beads. Lightly-crosslinked PDMS on the other side, due to its adhesive nature, enables iterative attachments on various materials under either dry or wet condition. Glucose oxidase (GOx) is immobilized by using the pores at the surface of highly-crosslinked PDMS matrix via a ship-in-a-bottle protocol of precipitation-based microscale enzyme reactor (p-MER), which consists of GOx adsorption, precipitation and chemical crosslinking (EAPC). As a result, crosslinked enzyme aggregates (CLEAs) of GOx not only are well entrapped within many pores of highly-crosslinked PDMS layer (ship-in-bottle) but also cover the external surface of matrix, both of which are well connected together. Highly-interconnected network of CLEAs themselves effectively prevents enzyme leaching, which shows the 25% residual activity of GOx under shaking at 200 rpm for 156 days after 48% initial drop of loosely-bound p-MER after 4 days. In presence of glucose, the underwater attachment of biocatalytic elastomer demonstrates the generation of hydrogen peroxide via p-MER-catalyzed glucose oxidation, exhibiting effective biocidal activities against both gram-positive S. aureus and gram-negative E. coli. Adhesion-induced GOx-catalyzed reaction also alleviates the biofouling of membrane, suggesting its extendibility to various engineering systems being suffered by biofouling. This study of biocatalytic elastomer has demonstrated its new opportunities for the facile and on-demand enzyme-catalyzed reactions in various environmental applications, such as bactericidal treatment, water treatment/purification, and pollutant degradation.

Data Association for Multi-Object Tracking via Deep Neural Networks.

With recent advances in object detection, the tracking-by-detection method has become mainstream for multi-object tracking in computer vision. The tracking-by-detection scheme necessarily has to resolve a problem of data association between existing tracks and newly received detections at each frame. In this paper, we propose a new deep neural network (DNN) architecture that can solve the data association problem with a variable number of both tracks and detections including false positives. The proposed network consists of two parts: encoder and decoder. The encoder is the fully connected network with several layers that take bounding boxes of both detection and track-history as inputs. The outputs of the encoder are sequentially fed into the decoder which is composed of the bi-directional Long Short-Term Memory (LSTM) networks with a projection layer. The final output of the proposed network is an association matrix that reflects matching scores between tracks and detections. To train the network, we generate training samples using the annotation of Stanford Drone Dataset (SDD). The experiment results show that the proposed network achieves considerably high recall and precision rate as the binary classifier for the assignment tasks. We apply our network to track multiple objects on real-world datasets and evaluate the tracking performance. The performance of our tracker outperforms previous works based on DNN and comparable to other state-of-the-art methods.

Hepatic artery reconstruction and successful management of its complications in living donor liver transplantation using a right lobe.

BACKGROUND: The aim of the present study was to improve the techniques of hepatic artery (HA) reconstruction and to properly manage arterial complications after living donor liver transplantation (LDLT). METHODS: Prospectively collected data collected from 371 patients who underwent adult LDLT using a right lobe from January 2000 to August 2009 were retrospectively reviewed. RESULTS: Of 17 patients (4.6%, 17/371) with double HA stumps in the graft, 12 patients (70.6%) received dual HA reconstruction. HA complications were composed of thrombosis (n = 6), pseudoaneurysm (n = 2), and stenosis (n = 4), showing 3.2% (12/371) of incidence. In patients with HA thrombosis, whereas operative thrombectomies with re-anastomosis rescued all the grafts in early attack (n = 3, ≤1 wk), angiographic thrombolysis successfully reestablished the flow in patients with late attack (n = 3, >1 wk). In all patients with HA complications, except for one, all of our treatment modalities - operation and angiographic intervention - resulted in successful rescue of grafts and no patient received re-transplantation because of HA complications. CONCLUSION: Prompt diagnosis of HA complications by serial post-operative Doppler ultrasound and corresponding treatment strategies, including operative and radiological intervention, can rescue both grafts and patients without necessitating re-transplantation.

Clinical analysis of living donor liver transplantation in patients with portal vein thrombosis.

The aim of this study was to improve outcomes in living donor liver transplantation (LDLT) patients with portal vein thrombosis (PVT). Of 246 adult patients who underwent LDLT with a right lobe graft between January 2000 and May 2007, PVT was diagnosed in 50 patients (20.3%), who were further subdivided into partial (n = 39, 78%) and complete (n = 11, 22%) types. Patients with PVT, especially complete PVT, showed high incidences of variceal bleeding (p = 0.021), operative RBC transfusion (p < 0.046) and a post-transplantation complications related to bleeding (p = 0.058). We also classified PVT according to its location and the presence of collaterals: type I (n = 41, 82%): PVT localized above the confluence of the splenic and superior mesenteric veins (SMV); type II (n = 7, 14%): PVT extending below the confluence with a patent distal SMV; type III (n = 2, 4%): complete portal vein and SMV thrombosis except for a coronary vein. LDLT could be safely undertaken in patients with PVT without increased mortality. In our type II and III PVT, when thrombectomy fails, jump grafting using a cryopreserved vessel may serve as a reliable alternative method to restore portal flow.

Chylopericardium Secondary to Lymphangiomyoma - A case report -.

Chylopericardium is a rare disease entity characterized by the accumulation of chylous fluid in the pericardial sac. It usually arises from mediastinal neoplasms, thrombosis of the subclavian vein, tuberculosis, nonsurgical trauma, thoracic or cardiac surgery. The spectrum of symptoms for chylopericardium varies from an incidental finding of cardiomegaly to dyspnea, upper abdominal discomfort, cough, chest pain, palpitation, fatigue. However, most of the patients are asymptomatic. The main purpose of treatment of chylopericardium is the prevention of cardiac tamponade and prevention of metabolic, nutritional, and immunological compromise due to chyle leak. Here, we report a case of chylopercardium secondary to lymphangiomyoma with review of the literature.