The rockefeller university

Stem cell technology can allow us to produce human neuronal cell types outside the body, but what exactly are stem cells, and what challenges are associated with their use? Stem cells are a kind of cell that has the capacity to self-renew to produce additional stem cells by mitosis, and also to differentiate into other-more mature-cell types. Stem cells are usually categorized as multipotent (able to give rise to multiple cells within a lineage), pluripotent (able to give rise to all cell types in an adult) and totipotent (able to give rise to all embryonic and adult lineages). Multipotent adult stem cells are found throughout the body, and they include neural stem cells. The challenge in utilizing adult stem cells for disease research is obtaining cells that are genetically matched to people with disease phenotypes, and being able to differentiate them into the appropriate cell types of interest. As adult neural stem cells reside in the brain, their isolation would require considerably invasive and dangerous procedures. In contrast, pluripotent stem cells are easy to obtain, due to the paradigm-shifting work on direct reprogramming of human skin fibroblasts into induced pluripotent stem cells. This work has enabled us to produce neurons that are genetically matched to individual patients. While we are able to isolate pluripotent stem cells from patients in a minimally invasive manner, we do not yet fully understand how to direct these cells to many of the medically important neuroendocrine fates. Progress in this direction continues to be made, on multiple fronts, and it involves using small molecules and proteins to mimic developmentally important signals, as well as building on advances in "reprogramming" to directly convert one cell type into another by forced expression of sets of transcription factors. An additional challenge involves providing these cells with the appropriate environment to induce their normal behavior outside the body. Despite these challenges, the promise of producing human neuroendocrine cell types in vitro gives opportunities for unique insights and is therefore worthwhile.

A search for the pair production of new light bosons, each decaying into a pair of muons, is performed with the CMS experiment at the LHC, using a dataset corresponding to an integrated luminosity of 20.7 fb(-1) collected in proton-proton collisions at center-of-mass energy of root s = 8 TeV. No excess is observed in the data relative to standard model background expectation and a model independent upper limit on the product of the cross section, branching fraction, and acceptance is derived. The results are compared with two benchmark models, the first one in the context of the next-to-minimal super-symmetric standard model, and the second one in scenarios containing a hidden sector, including those predicting a nonnegligible light boson lifetime. (C) 2015 CERN for the benefit of the CMS Collaboration. Published by Elsevier B.V.

Electrophysiology has recently evolved into an interactive, high-throughput endeavor. Recording from dozens to hundreds of electrodes is today routine; novel means of manipulating the system in real time, through electrical stimulation, optogenetics or sensory manipulation are allowing us to decipher neural circuit function at an unparalleled rate. To contribute to the wide dissemination of such techniques, we present an open hardware project, High-Channel Count Electrophysiology (HiCCE), aiming to produce low-cost, high-channel count (>= 128 channels) electrophysiology instrumentation capable of fast data acquisition rates, real-time processing and feedback capabilities. Our design is centered on an open standard, FPGA Mezzanine Card (FMC), which permits a varied choice of FPGA carrier architectures suited to different laboratory experimental needs. The HiCCE-128, a low-cost high-performance 128-channel data acquisition board for small voltage signals, is being introduced. It is a FMC module that can be operated from any FPGA carrier conforming to the FMC/VITA57 standard. This specialized board with a low input referred noise of about 3 mu V is capable of acquiring 128 channels simultaneously at 31.25 kS/s per channel with 16 effective bits of resolution. We present the global architecture and some preliminary measurement to illustrate its potential for electrophysiological and medical applications.

Recognition that the live yellow fever vaccine may rarely be associated with viscerotropic disease (YEL-AVD) has diminished its safety status. However, the vaccine remains the principal tool for limiting the occurrence of yellow fever, making large portions of Africa and South America more habitable. The subject has previously been exhaustively reviewed. Novel concepts in the current report include the description of a systematic method for deciding whom to vaccinate, recommendations for obtaining data helpful in making that decision, and suggestions for additional study. The vaccine is indeed a worthy friend, but its adverse reactions need to be recognized.

Ant colonies provide well-protected and resource-rich environments for a plethora of symbionts. Historically, most studies of ants and their symbionts have had a narrow taxonomic scope, often focusing on a single ant or symbiont species. Here we discuss the prospects of studying these assemblies in a community ecology context using the framework of ecological network analysis. We introduce three basic network metrics that we consider particularly relevant for improving our knowledge of ant-symbiont communities: interaction specificity, network modularity, and phylogenetic signal. We then discuss army ant symbionts as examples of large and primarily parasitic communities, and symbiotic sternorrhynchans as examples of generally smaller and primarily mutualistic communities in the context of these network analyses. We argue that this approach will provide new and complementary insights into the evolutionary and ecological dynamics between ants and their many associates, and will facilitate comparisons across different ant-symbiont assemblages as well as across different types of ecological networks.

A search for fermionic top quark partners T of charge 2/3 is presented. The search is carried out in proton-proton collisions corresponding to an integrated luminosity of 19.7 fb(-1) collected at a center-of-mass energy of root s = 8 TeV with the CMS detector at the LHC. The T quarks are assumed to be produced strongly in pairs and can decay into tH, tZ, and bW. The search is performed in five exclusive channels: a single-lepton channel, a multilepton channel, two all-hadronic channels optimized either for the bW or the tH decay, and one channel in which the Higgs boson decays into two photons. The results are found to be compatible with the standard model expectations in all the investigated final states. A statistical combination of these results is performed and lower limits on the T quark mass are set. Depending on the branching fractions, lower mass limits between 720 and 920 GeV at 95% confidence level are found. These are among the strongest limits on vectorlike T quarks obtained to date.

The eukaryotic replisome is a multiprotein machine that contains DNA polymerases, sliding clamps, helicase, and primase along with several factors that participate in cell cycle and checkpoint control. The detailed structure of the 11-subunit CMG helicase (Cdc45/Mcm2-7/GINS) has been solved recently by cryoEM single-particle 3D reconstruction and reveals pumpjack motions that imply an unexpected mechanism of DNA translocation. CMG is also the organizing center of the replisome. Recent in vitro reconstitution of leading and lagging strand DNA synthesis has enabled structural analysis of the replisome. By building the replisome in stages from pure proteins, single-particle EM studies have identified the overall architecture of the eukaryotic replisome. Suprisingly leading and lagging strand polymerases bind to opposite faces of the CMG helicase, unlike the long-held view that DNA polymerases are located in back of the helicase to act on the unwound strands.