Treatment of malignant esophageal obstructions with covered metallic Z stents: long-term results in 52 patients

PURPOSE: To prospectively evaluate the clinical efficacy of silicone-covered Gianturco-R?sch self-expandable Z (GRZ) stents in the treatment of malignant esophageal obstruction. PATIENTS AND METHODS: GRZ stents were placed in 52 patients (39 men, 13 women) with severe dysphagia due to high-grade malignant esophageal obstruction. RESULTS: Stent placement was technically successful, and immediate relief of dysphagia was achieved in 50 of 52 patients (96%), with long-term relief in 47 patients (90%). Fifty-one patients (98%) died during follow-up (range, 1 week to 33 months; mean, 4.3 months). Late complications were most prevalent and included stent migration (n = 5), food impaction (n = 2), chest pain (n = 2), membrane disruption with tumor ingrowth (n = 1), granulomatous reaction above the stent (n = 1), esophageal perforation with mediastinitis (n = 1), and upper gastrointestinal hemorrhage (n = 4). Twelve complications were easily managed with medical, endoscopic, or radiologic intervention. Four deaths may have been related to stent placement (early mortality rate, 7.7%). CONCLUSION: GRZ stents provide relatively safe and effective long-term palliation in patients with severe, malignant esophageal obstruction.     

Flexible high-performance carbon nanotube integrated circuits

Carbon nanotube thin-film transistors are expected to enable the fabrication of high-performance, flexible and transparent devices using relatively simple techniques. However, as-grown nanotube networks usually contain both metallic and semiconducting nanotubes, which leads to a trade-off between charge-carrier mobility (which increases with greater metallic tube content) and on/off ratio (which decreases). Many approaches to separating metallic nanotubes from semiconducting nanotubes have been investigated, but most lead to contamination and shortening of the nanotubes, thus reducing performance. Here, we report the fabrication of high-performance thin-film transistors and integrated circuits on flexible and transparent substrates using floating-catalyst chemical vapour deposition followed by a simple gas-phase filtration and transfer process. The resulting nanotube network has a well-controlled density and a unique morphology, consisting of long (~10 μm) nanotubes connected by low-resistance Y-shaped junctions. The transistors simultaneously demonstrate a mobility of 35 cm(2) V(-1) s(-1) and an on/off ratio of 6 × 10(6). We also demonstrate flexible integrated circuits, including a 21-stage ring oscillator and master-slave delay flip-flops that are capable of sequential logic. Our fabrication procedure should prove to be scalable, for example, by using high-throughput printing techniques.     

Self-assembly of carbon-nanotube-based single-electron memories

We demonstrate the wafer-scale integration of single-electron memories based on carbon nanotube field-effect transistors (CNFETs) using a process based entirely on self assembly. First, a "dry" self-assembly step based on chemical vapor deposition (CVD) allows the growth and connection of CNFETs. Next, a "wet" self-assembly step is used to attach a single 30-nm-diameter gold bead in the nanotube vicinity via chemical functionalization. The bead is used as the memory storage node while the CNFET operating in the subthreshold regime acts as an electrometer exhibiting exponential gain. Below 60 K, the transfer characteristics of gold-CNFETs show highly reproducible hysteretic steps. Evaluation of the capacitance confirms that these current steps originate from the controlled storage of single electrons with a retention time that exceeds 550 s at 4 K.     

Using Forward Reachability Analysis for Verification of Lossy Channel Systems

We consider symbolic on-the-fly verification methods for systems of finite-state machines that communicate by exchanging messages via unbounded and lossy FIFO queues. We propose a novel representation formalism, called simple regular expressions (SREs), for representing sets of states of protocols with lossy FIFO channels. We show that the class of languages representable by SREs is exactly the class of downward closed languages that arise in the analysis of such protocols. We give methods for computing (i) inclusion between SREs, (ii) an SRE representing the set of states reachable by executing a single transition in a system, and (iii) an SRE representing the set of states reachable by an arbitrary number of executions of a control loop. All these operations are rather simple and can be carried out in polynomial time.With these techniques, one can straightforwardly construct an algorithm which explores the set of reachable states of a protocol, in order to check various safety properties. We also show how one can perform model-checking of LTL properties, using a standard automata-theoretic construction. It should be noted that all these methods are by necessity incomplete, even for the class of protocols with lossy channels.To illustrate the applicability of our methods, we have developed a tool prototype and used the tool for automatic verification of (a parameterized version of) the Bounded Retransmission Protocol.     

Detection of single electrons by means of a Micromegas-covered MediPix2 pixel CMOS readout circuit

A small drift chamber was read out by means of a MediPix2 readout chip as a direct anode. A Micromegas foil was placed above the chip, and electron multiplication occurred in the gap. With a He/isobutane 80/20 mixture, gas multiplication factors up to tens of thousands were achieved, resulting in an efficiency for detecting single electrons of better than 90%. We recorded many frames containing 2D images with tracks from cosmic muons. Along these tracks, electron clusters were observed, as well as δ-rays.     

Transforming spaces into lively public open places: case studies of practical interventions

Urban public open spaces are an important part of the urban environment, creating the framework for public life. The transformation of open space into successful public places is crucial in this regard. In the context of target-driven performance it is essential to identify the value of successful public open places, along with characteristics that define them. This research evaluated three case studies in Belgium (Namur, Wavre and La Louviere) which successfully transformed spaces into lively public open places. The transformation was captured by means of before-and-after imagery and analyses, and evaluated in terms of space-usage prior to, and after redesign, along with the experience and added value that the redesign brought to the area.     

The C-Terminal Acidic Tail Modulates the Anticancer Properties of HMGB1

Energy metabolism reprogramming was recently listed as a hallmark of cancer. In this process, the switch from pyruvate kinase isoenzyme type M1 to pyruvate kinase isoenzyme type M2 (PKM2) is believed to play a crucial role. Interestingly, the activity of the active form of PKM2 can efficiently be inhibited by the high-mobility group box 1 (HMGB1) protein, leading to a rapid blockage of glucose-dependent aerobic respiration and cancer cell death. HMGB1 is a member of the HMG protein family. It contains two DNA-binding HMG-box domains and an acidic C-terminal tail capable of positively or negatively modulating its biological properties. In this work, we report that the deletion of the C-terminal tail of HMGB1 increases its activity towards a large panel of cancer cells without affecting the viability of normal immortalized fibroblasts. Moreover, in silico analysis suggests that the truncated form of HMGB1 retains the capacity of the full-length protein to interact with PKM2. However, based on the capacity of the cells to circumvent oxidative phosphorylation inhibition, we were able to identify either a cytotoxic or cytostatic effect of the proteins. Together, our study provides new insights in the characterization of the anticancer activity of HMGB1.     

Effect of a hard coat layer on buckle delamination of thin ITO layers on a compliant elasto-plastic substrate: An experimental–numerical approach

Layer buckling and delamination is a common interfacial failure phenomenon in thin film multi-layer structures that are used in flexible display applications. Typically, the substrate is coated on both sides with a hybrid coating, called a hard coat (HC), which acts as a gas barrier and also increases the scratch resistance. In this paper 250 nm thick indium tin oxide (ITO) layers have been deposited on a 200 μm thick high temperature aromatic polyester substrate (Arylite^TM), with and without a 3 μm HC. In order to study the influence of this HC layer on delamination phenomena, two-point bending experiments are performed from which buckle width and height values are measured after straightening of the sample. An analytical model and a finite element (FE) model are developed to estimate the adhesion properties from the measured buckle geometries. In the numerical model, the initiation and propagation of the delamination process is described by cohesive zone elements, of which the parameters are extracted from response surface model (RSM) results. Furthermore, the numerical model is used to illustrate the significant change in buckle geometry upon load reversal, i.e. from loaded to straightened state, which is governed by the elasto-plastic behavior of the substrate material. It is concluded that the addition of a HC layer significantly decreases the adhesion of the ITO layer. The latter is determined as function of the actual mode angle.