Individually addressable AlInGaN micro-LED arrays with CMOS control and subnanosecond output pulses

We report the fabrication and characterization of an ultraviolet (370 nm) emitting AlInGaN-based micro-light- emitting diode (micro-LED) array integrated with complementary metal-oxide-semiconductor control electronics. This configuration allows an 8 × 8 array of micro-LED pixels, each of 72-mum diameter, to be individually addressed. The micro-LED pixels can be driven in direct current (dc), square wave, or pulsed operation, with linear feedback shift registers (LFSRs) allowing the output of the micro-LED pixels to mimic that of an optical data transmitter. We present the optical output power versus drive current characteristics of an individual pixel, which show a micro-LED output power of up to 570 muW in dc operation. Representative optical pulse trains demonstrating the micro-LEDs driven in square wave and LFSR modes, and controlled optical pulsewidths from 300 ps to 40 ns are also presented

A Simulation Model for Digital Silicon Photomultipliers

We propose a simulator model to estimate the performance of digital Silicon Photomultipliers (dSiPM) based on Single Photon Avalanche Diodes (SPADs) in terms of detection rate of photons incident on the sensor. The work provides guidelines for efficient array structure depending on: the number of SPADs, fill factor, area of both SPADs and array. A comparison of the main techniques present in the literature to digitally combine multiple outputs into single channel is included with simulated results showing promising higher detection rates for XOR-based dSiPMs. Mathematical expressions are derived to estimate dSiPM parameters such as maximum detection rate and detector dead time as functions of the mentioned design parameters

Mitochondrial mutations and metabolic adaptation in pancreatic cancer.

BACKGROUND: Pancreatic cancer has a five-year survival rate of ~8%, with characteristic molecular heterogeneity and restricted treatment options. Targeting metabolism has emerged as a potentially effective therapeutic strategy for cancers such as pancreatic cancer, which are driven by genetic alterations that are not tractable drug targets. Although somatic mitochondrial genome (mtDNA) mutations have been observed in various tumors types, understanding of metabolic genotype-phenotype relationships is limited. METHODS: We deployed an integrated approach combining genomics, metabolomics, and phenotypic analysis on a unique cohort of patient-derived pancreatic cancer cell lines (PDCLs). Genome analysis was performed via targeted sequencing of the mitochondrial genome (mtDNA) and nuclear genes encoding mitochondrial components and metabolic genes. Phenotypic characterization of PDCLs included measurement of cellular oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) using a Seahorse XF extracellular flux analyser, targeted metabolomics and pathway profiling, and radiolabelled glutamine tracing. RESULTS: We identified 24 somatic mutations in the mtDNA of 12 patient-derived pancreatic cancer cell lines (PDCLs). A further 18 mutations were identified in a targeted study of ~1000 nuclear genes important for mitochondrial function and metabolism. Comparison with reference datasets indicated a strong selection bias for non-synonymous mutants with predicted functional effects. Phenotypic analysis showed metabolic changes consistent with mitochondrial dysfunction, including reduced oxygen consumption and increased glycolysis. Metabolomics and radiolabeled substrate tracing indicated the initiation of reductive glutamine metabolism and lipid synthesis in tumours. CONCLUSIONS: The heterogeneous genomic landscape of pancreatic tumours may converge on a common metabolic phenotype, with individual tumours adapting to increased anabolic demands via different genetic mechanisms. Targeting resulting metabolic phenotypes may be a productive therapeutic strategy

The effects of centralising electoral management board design

The public administration of elections frequently fails. Variation in the performance of electoral management boards around the world has been demonstrated, illustrated by delays in the count, inaccurate or incomplete voter registers, or severe queues at polling stations. Centralising the management of the electoral process has often been proposed as a solution. There has been little theorisation and no empirical investigations into the effects that centralising an already decentralised system would have, however. This article addresses this lacuna by conceptualising centralisation through the literature on bureaucratic control and discretion. It then empirically investigates the effects through a case study of centralisation in two UK referendums. Semi-structured interviews were used with those who devised the policy instrument and those who were subject to it. The introduction of central directions had some of the desired effects such as producing more consistent services and eliminating errors. It also had side effects, however, such as reducing economic efficiency in some areas and overlooking local knowledge. Furthermore, the reforms caused a decline of staff morale, job satisfaction and souring of relations among stakeholder organisations. The process of making organisational change therefore warrants closer attention by policy makers and future scholarship on electoral integrity

Belediye Müzesi

Taha Toros Arşivi, Dosya No: 114-Müzelerİstanbul Kalkınma Ajansı (TR10/14/YEN/0033) İstanbul Development Agency (TR10/14/YEN/0033

Seasonal pulses of Marburg virus circulation in juvenile Rousettus aegyptiacus bats coincide with periods of increased risk of human infection

Marburg virus (family Filoviridae) causes sporadic outbreaks of severe hemorrhagic disease in sub-Saharan Africa. Bats have been implicated as likely natural reservoir hosts based most recently on an investigation of cases among miners infected in 2007 at the Kitaka mine, Uganda, which contained a large population of Marburg virus-infected Rousettus aegyptiacus fruit bats. Described here is an ecologic investigation of Python Cave, Uganda, where an American and a Dutch tourist acquired Marburg virus infection in December 2007 and July 2008. More than 40,000 R. aegyptiacus were found in the cave and were the sole bat species present. Between August 2008 and November 2009, 1,622 bats were captured and tested for Marburg virus. Q-RT-PCR analysis of bat liver/spleen tissues indicated ,2.5% of the bats were actively infected, seven of which yielded Marburg virus isolates. Moreover, Q-RT-PCR-positive lung, kidney, colon and reproductive tissues were found, consistent with potential for oral, urine, fecal or sexual transmission. The combined data for R. aegyptiacus tested from Python Cave and Kitaka mine indicate low level horizontal transmission throughout the year. However, Q-RT-PCR data show distinct pulses of virus infection in older juvenile bats (,six months of age) that temporarily coincide with the peak twiceyearly birthing seasons. Retrospective analysis of historical human infections suspected to have been the result of discrete spillover events directly from nature found 83% (54/65) events occurred during these seasonal pulses in virus circulation, perhaps demonstrating periods of increased risk of human infection. The discovery of two tags at Python Cave from bats marked at Kitaka mine, together with the close genetic linkages evident between viruses detected in geographically distant locations, are consistent with R. aegyptiacus bats existing as a large meta-population with associated virus circulation over broad geographic ranges. These findings provide a basis for developing Marburg hemorrhagic fever risk reduction strategies.The Department of Health and Human Serviceshttp://www.plospathogens.or