Velocity Correlations in Driven Two-Dimensional Granular Media

Simulations of volumetrically forced granular media in two dimensions produce s tates with nearly homogeneous density. In these states, long-range velocity correlations with a characteristic vortex structure develop; given sufficient time, the correlations fill the entire simulated area. These velocity correlations reduce the rate and violence of collisions, so that pressure is smaller for driven inelastic particles than for undriven elastic particles in the same thermodynamic state. As the simulation box size increases, the effects of veloc ity correlations on the pressure are enhanced rather than reduced.Comment: 12 pages, 6 figures, 21 reference

The emerging role of sarcopenia as a prognostic indicator in patients undergoing abdominal wall hernia repairs: a systematic review of the literature

Background There is strong evidence suggesting that excessive fat distribution, for example, in the bowel mesentery or a reduction in lean body mass (sarcopenia) can influence short-, mid-, and long-term outcomes from patients undergoing various types of surgery. Body composition (BC) analysis aims to measure and quantify this into a parameter that can be used to assess patients being treated for abdominal wall hernia (AWH). This study aims to review the evidence linking quantification of BC with short- and long-term abdominal wall hernia repair outcomes. Methods A systematic review was performed according to the PRISMA guidelines. The literature search was performed on all studies that included BC analysis in patients undergoing treatment for AWH using Medline, Google Scholar and Cochrane databases by two independent reviewers. Outcomes of interest included short-term recovery, recurrence outcomes, and long-term data. Results 201 studies were identified, of which 4 met the inclusion criteria. None of the studies were randomized controlled trials and all were cohort studies. There was considerable variability in the landmark axial levels and skeletal muscle(s) chosen for analysis, alongside the methods of measuring the cross-sectional area and the parameters used to define sarcopenia. Only two studies identified an increased risk of postoperative complications associated with the presence of sarcopenia. This included an increased risk of hernia recurrence, postoperative ileus and prolonged hospitalisation. Conclusion There is some evidence to suggest that BC techniques could be used to help predict surgical outcomes and allow early optimisation in AWH patients. However, the lack of consistency in chosen methodology, combined with the outdated definitions of sarcopenia, makes drawing any conclusions difficult. Whether body composition modification can be used to improve outcomes remains to be determined

Pancreaticoduodenectomy with right hemicolectomy for advanced malignancy: a single UK hepatopancreaticobiliary centre experience

Aim Locally advanced intestinal neoplasms including colon cancer may require radical en bloc pancreaticoduodenectomy and right hemicolectomy (PD-RC) to achieve curative, margin-negative resection, but the safety and benefit of this uncommon procedure has not been established. The Association of Coloproctology of Great Britain and Ireland IMPACT initiative has also highlighted a lack of awareness about current services available within the UK for patients with advanced colorectal cancer and concerns about low-volume centres managing complex cases. Thus, we aimed to review the feasibility, safety and long-term outcomes of this procedure at a single high-volume hepatopancreaticobiliary surgery unit in the UK. Method A retrospective cohort study was performed using a database of all consecutive patients with intestinal cancer who had been referred to our regional advanced multidisciplinary team and undergone PD-RC in a 7-year period (2013–2020). Clinico-pathological and outcome data were reviewed. Results Ten patients (mean age 54 ± 13, 8/10 men) were identified. Final histology revealed the primary tumour sites were colon (n = 7) and duodenum (n = 3). R0 resection was achieved in all cases. The major complication rate (Clavien–Dindo ≥ 3) was 10% (1/10) with no deaths within 90 days of surgery. The Kaplan–Meier estimated 5-year overall survival was 83.3% (95% CI 58.3%–100%). Univariate survival analysis identified perineural invasion and extra-colonic origin as predictors of poor survival (log-rank P < 0.05). Conclusion En bloc PD-RC for locally advanced intestinal cancer can be performed safely with a high proportion of margin-negative resections and resultant long-term survival in carefully selected patients

Transit Photometry as an Exoplanet Discovery Method

Photometry with the transit method has arguably been the most successful exoplanet discovery method to date. A short overview about the rise of that method to its present status is given. The method's strength is the rich set of parameters that can be obtained from transiting planets, in particular in combination with radial velocity observations; the basic principles of these parameters are given. The method has however also drawbacks, which are the low probability that transits appear in randomly oriented planet systems, and the presence of astrophysical phenomena that may mimic transits and give rise to false detection positives. In the second part we outline the main factors that determine the design of transit surveys, such as the size of the survey sample, the temporal coverage, the detection precision, the sample brightness and the methods to extract transit events from observed light curves. Lastly, an overview over past, current and future transit surveys is given. For these surveys we indicate their basic instrument configuration and their planet catch, including the ranges of planet sizes and stellar magnitudes that were encountered. Current and future transit detection experiments concentrate primarily on bright or special targets, and we expect that the transit method remains a principal driver of exoplanet science, through new discoveries to be made and through the development of new generations of instruments.Comment: Review chapte

Tumor innate immunity primed by specific interferon-stimulated endogenous retroviruses.

Mesenchymal tumor subpopulations secrete pro-tumorigenic cytokines and promote treatment resistance1-4. This phenomenon has been implicated in chemorefractory small cell lung cancer and resistance to targeted therapies5-8, but remains incompletely defined. Here, we identify a subclass of endogenous retroviruses (ERVs) that engages innate immune signaling in these cells. Stimulated 3 prime antisense retroviral coding sequences (SPARCS) are oriented inversely in 3' untranslated regions of specific genes enriched for regulation by STAT1 and EZH2. Derepression of these loci results in double-stranded RNA generation following IFN-γ exposure due to bi-directional transcription from the STAT1-activated gene promoter and the 5' long terminal repeat of the antisense ERV. Engagement of MAVS and STING activates downstream TBK1, IRF3, and STAT1 signaling, sustaining a positive feedback loop. SPARCS induction in human tumors is tightly associated with major histocompatibility complex class 1 expression, mesenchymal markers, and downregulation of chromatin modifying enzymes, including EZH2. Analysis of cell lines with high inducible SPARCS expression reveals strong association with an AXL/MET-positive mesenchymal cell state. While SPARCS-high tumors are immune infiltrated, they also exhibit multiple features of an immune-suppressed microenviroment. Together, these data unveil a subclass of ERVs whose derepression triggers pathologic innate immune signaling in cancer, with important implications for cancer immunotherapy

Dual-gated bilayer graphene hot electron bolometer

Detection of infrared light is central to diverse applications in security, medicine, astronomy, materials science, and biology. Often different materials and detection mechanisms are employed to optimize performance in different spectral ranges. Graphene is a unique material with strong, nearly frequency-independent light-matter interaction from far infrared to ultraviolet, with potential for broadband photonics applications. Moreover, graphene's small electron-phonon coupling suggests that hot-electron effects may be exploited at relatively high temperatures for fast and highly sensitive detectors in which light energy heats only the small-specific-heat electronic system. Here we demonstrate such a hot-electron bolometer using bilayer graphene that is dual-gated to create a tunable bandgap and electron-temperature-dependent conductivity. The measured large electron-phonon heat resistance is in good agreement with theoretical estimates in magnitude and temperature dependence, and enables our graphene bolometer operating at a temperature of 5 K to have a low noise equivalent power (33 fW/Hz1/2). We employ a pump-probe technique to directly measure the intrinsic speed of our device, >1 GHz at 10 K.Comment: 5 figure

Changes in microphytobenthos fluorescence over a tidal cycle: implications for sampling designs

Intertidal microphytobenthos (MPB) are important primary producers and provide food for herbivores in soft sediments and on rocky shores. Methods of measuring MPB biomass that do not depend on the time of collection relative to the time of day or tidal conditions are important in any studies that need to compare temporal or spatial variation, effects of abiotic factors or activity of grazers. Pulse amplitude modulated (PAM) fluorometry is often used to estimate biomass of MPB because it is a rapid, non-destructive method, but it is not known how measures of fluorescence are altered by changing conditions during a period of low tide. We investigated this experimentally using in situ changes in minimal fluorescence (F) on a rocky shore and on an estuarine mudflat around Sydney (Australia), during low tides. On rocky shores, the time when samples are taken during low tide had little direct influence on measures of fluorescence as long as the substratum is dry. Wetness from wave-splash, seepage from rock pools, run-off, rainfall, etc., had large consequences for any comparisons. On soft sediments, fluorescence was decreased if the sediment dried out, as happens during low-spring tides on particularly hot and dry days. Surface water affected the response of PAM and therefore measurements used to estimate MPB, emphasising the need for care to ensure that representative sampling is done during low tide