Interacting Supernovae: Types IIn and Ibn

Supernovae (SNe) that show evidence of strong shock interaction between their ejecta and pre-existing, slower circumstellar material (CSM) constitute an interesting, diverse, and still poorly understood category of explosive transients. The chief reason that they are extremely interesting is because they tell us that in a subset of stellar deaths, the progenitor star may become wildly unstable in the years, decades, or centuries before explosion. This is something that has not been included in standard stellar evolution models, but may significantly change the end product and yield of that evolution, and complicates our attempts to map SNe to their progenitors. Another reason they are interesting is because CSM interaction is an efficient engine for making bright transients, allowing super-luminous transients to arise from normal SN explosion energies, and allowing transients of normal SN luminosities to arise from sub-energetic explosions or low radioactivity yield. CSM interaction shrouds the fast ejecta in bright shock emission, obscuring our normal view of the underlying explosion, and the radiation hydrodynamics of the interaction is challenging to model. The CSM interaction may also be highly non-spherical, perhaps linked to binary interaction in the progenitor system. In some cases, these complications make it difficult to definitively tell the difference between a core-collapse or thermonuclear explosion, or to discern between a non-terminal eruption, failed SN, or weak SN. Efforts to uncover the physical parameters of individual events and connections to possible progenitor stars make this a rapidly evolving topic that continues to challenge paradigms of stellar evolution.Comment: Final draft of a chapter in the "SN Handbook". Accepted. 25 pages, 3 fig

E1-Like Activating Enzyme Atg7 Is Preferentially Sequestered into p62 Aggregates via Its Interaction with LC3-I

p62 is constitutively degraded by autophagy via its interaction with LC3. However, the interaction of p62 with LC3 species in the context of the LC3 lipidation process is not specified. Further, the p62-mediated protein aggregation's effect on autophagy is unclear. We systemically analyzed the interactions of p62 with all known Atg proteins involved in LC3 lipidation. We find that p62 does not interact with LC3 at the stages when it is being processed by Atg4B or when it is complexed or conjugated with Atg3. p62 does interact with LC3-I and LC3-I:Atg7 complex and is preferentially recruited by LC3-II species under autophagic stimulation. Given that Atg4B, Atg3 and LC3-Atg3 are indispensable for LC3-II conversion, our study reveals a protective mechanism for Atg4B, Atg3 and LC3-Atg3 conjugate from being inappropriately sequestered into p62 aggregates. Our findings imply that p62 could potentially impair autophagy by negatively affecting LC3 lipidation and contribute to the development of protein aggregate diseases. © 2013 Gao et al

Clamp-Crushing versus stapler hepatectomy for transection of the parenchyma in elective hepatic resection (CRUNSH) - A randomized controlled trial (NCT01049607)

<p>Abstract</p> <p>Background</p> <p>Hepatic resection is still associated with significant morbidity. Although the period of parenchymal transection presents a crucial step during the operation, uncertainty persists regarding the optimal technique of transection. It was the aim of the present randomized controlled trial to evaluate the efficacy and safety of hepatic resection using the technique of stapler hepatectomy compared to the simple clamp-crushing technique.</p> <p>Methods/Design</p> <p>The CRUNSH Trial is a prospective randomized controlled single-center trial with a two-group parallel design. Patients scheduled for elective hepatic resection without extrahepatic resection at the Department of General-, Visceral- and Transplantation Surgery, University of Heidelberg are enrolled into the trial and randomized intraoperatively to hepatic resection by the clamp-crushing technique and stapler hepatectomy, respectively. The primary endpoint is total intraoperative blood loss. A set of general and surgical variables are documented as secondary endpoints. Patients and outcome-assessors are blinded for the treatment intervention.</p> <p>Discussion</p> <p>The CRUNSH Trial is the first randomized controlled trial to evaluate efficacy and safety of stapler hepatectomy compared to the clamp-crushing technique for parenchymal transection during elective hepatic resection.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov: <a href="http://www.clinicaltrials.gov/ct2/show/NCT01049607">NCT01049607</a></p

Compositional, physico-mechanical and functional properties of two Ghanaian cowpea (Vigna unguiculata) varieties

Cowpea (Vigna unguiculata) is a legume that is cultivated throughout Africa and contributes a significant amount of plant-based protein to human diets. There are many varieties of cowpeas, and these have varying seed characteristics such as shape, size, colour and nutritional properties. The compositional, physico-mechanical, and functional properties of two new cowpea seed varieties were investigated in order to determine their full food-use potentials as well as key parameters for their postharvest machinery for processing, handling, and storage. The proximate composition of the two cowpea cultivars was determined using standard methods. Physico-mechanical analyses carried out were the hundred-seed weight and volume, bulk density, true density, size, aspect ratio, surface area, equivalent diameter, porosity and angle of repose. Functional properties determined were cooking time and water uptake of the grain as well as water and oil absorption, foam capacity and stability, and emulsion capacity and stability of the flour. The Padi-Tuya variety was longer, broader and thicker than Wang Kae. The results showed both varieties to be useful sources of macronutrients. The moisture, fat and fibre in Wang Kae were significantly higher (p&lt;0.05) than Padi-Tuya. However, both cowpea varieties had comparable protein levels of 17.7 g/100 g. The cooking time, hydration capacities and indices of the two varieties were also significantly different (p&lt;0.05), but their swelling capacities, swelling and water uptake indices were comparable. Cooking times were 40 and 62 min for Padi-Tuya and Wang Kae, respectively. The water and oil absorption capacities, as well as the swelling indices, were similar, but their emulsion capacities and stabilities were significantly different (p&lt;0.05) for the flour. Padi-Tuya had a higher foam capacity, but was less stable, than Wang Kae. The physico-mechanical properties determined would aid in the design of cleaning, handling and other processing machinery as well as storage facilities for the new cowpeas. The functional and the compositional parameters would assist in the food formulations

Stability of quantized time-delay nonlinear systems: A Lyapunov-Krasowskii-functional approach

Lyapunov-Krasowskii functionals are used to design quantized control laws for nonlinear continuous-time systems in the presence of constant delays in the input. The quantized control law is implemented via hysteresis to prevent chattering. Under appropriate conditions, our analysis applies to stabilizable nonlinear systems for any value of the quantization density. The resulting quantized feedback is parametrized with respect to the quantization density. Moreover, the maximal allowable delay tolerated by the system is characterized as a function of the quantization density.Comment: 31 pages, 3 figures, to appear in Mathematics of Control, Signals, and System

Correlation between compartmental tenofovir concentrations and an ex vivo rectal biopsy model of tissue infectibility in the RMP-02/MTN-006 phase 1 study

Design: Phase 1, randomized, two-site (US), double-blind, placebo-controlled study of sexually-abstinent males and females

Prognostic value of lymph node ratio and extramural vascular invasion on survival for patients undergoing curative colon cancer resection

There was no study funding. We are grateful to Tony Rafferty (Tailored Information for the People of Scotland, TIPs) for providing survival data.Peer reviewedPublisher PD

Hydrostatic pressure does not cause detectable changes to survival of human retinal ganglion

Purpose: Elevated intraocular pressure (IOP) is a major risk factor for glaucoma. One consequence of raised IOP is that ocular tissues are subjected to increased hydrostatic pressure (HP). The effect of raised HP on stress pathway signaling and retinal ganglion cell (RGC) survival in the human retina was investigated. Methods: A chamber was designed to expose cells to increased HP (constant and fluctuating). Accurate pressure control (10-100mmHg) was achieved using mass flow controllers. Human organotypic retinal cultures (HORCs) from donor eyes (<24h post mortem) were cultured in serum-free DMEM/HamF12. Increased HP was compared to simulated ischemia (oxygen glucose deprivation, OGD). Cell death and apoptosis were measured by LDH and TUNEL assays, RGC marker expression by qRT-PCR (THY-1) and RGC number by immunohistochemistry (NeuN). Activated p38 and JNK were detected by Western blot. Results: Exposure of HORCs to constant (60mmHg) or fluctuating (10-100mmHg; 1 cycle/min) pressure for 24 or 48h caused no loss of structural integrity, LDH release, decrease in RGC marker expression (THY-1) or loss of RGCs compared with controls. In addition, there was no increase in TUNEL-positive NeuN-labelled cells at either time-point indicating no increase in apoptosis of RGCs. OGD increased apoptosis, reduced RGC marker expression and RGC number and caused elevated LDH release at 24h. p38 and JNK phosphorylation remained unchanged in HORCs exposed to fluctuating pressure (10-100mmHg; 1 cycle/min) for 15, 30, 60 and 90min durations, whereas OGD (3h) increased activation of p38 and JNK, remaining elevated for 90min post-OGD. Conclusions: Directly applied HP had no detectable impact on RGC survival and stress-signalling in HORCs. Simulated ischemia, however, activated stress pathways and caused RGC death. These results show that direct HP does not cause degeneration of RGCs in the ex vivo human retina

Extracting the rho meson wavefunction from HERA data

We extract the light-cone wavefunctions of the rho meson using the HERA data on diffractive rho photoproduction. We find good agreement with predictions for the distribution amplitude based on QCD sum rules and from the lattice. We also find that the data prefer a transverse wavefunction with enhanced end-point contributions.Comment: 13 pages, 7 figures, significant improvements over the original version with a new section on distribution amplitudes adde

Astrocytic Ion Dynamics: Implications for Potassium Buffering and Liquid Flow

We review modeling of astrocyte ion dynamics with a specific focus on the implications of so-called spatial potassium buffering, where excess potassium in the extracellular space (ECS) is transported away to prevent pathological neural spiking. The recently introduced Kirchoff-Nernst-Planck (KNP) scheme for modeling ion dynamics in astrocytes (and brain tissue in general) is outlined and used to study such spatial buffering. We next describe how the ion dynamics of astrocytes may regulate microscopic liquid flow by osmotic effects and how such microscopic flow can be linked to whole-brain macroscopic flow. We thus include the key elements in a putative multiscale theory with astrocytes linking neural activity on a microscopic scale to macroscopic fluid flow.Comment: 27 pages, 7 figure