298 research outputs found
Effects of invisible particle emission on global inclusive variables at hadron colliders
We examine the effects of invisible particle emission in conjunction with QCD
initial state radiation (ISR) on quantities designed to probe the mass scale of
new physics at hadron colliders, which involve longitudinal as well as
transverse final-state momenta. This is an extension of our previous treatment,
arXiv:0903.2013, of the effects of ISR on global inclusive variables. We
present resummed results on the visible invariant mass distribution and compare
them to parton-level Monte Carlo results for top quark and gluino
pair-production at the LHC. There is good agreement as long as the visible
pseudorapidity interval is large enough (eta ~ 3). The effect of invisible
particle emission is small in the case of top pair production but substantial
for gluino pair production. This is due mainly to the larger mass of the
intermediate particles in gluino decay (squarks rather than W-bosons). We also
show Monte Carlo modelling of the effects of hadronization and the underlying
event. The effect of the underlying event is large but may be approximately
universal.Comment: 22 pages, expanded sections and other minor modifications. Version
published in JHE
Study protocol for a randomised, double-blind, placebo-controlled crossover trial assessing the impact of the SGLT2 inhibitor empagliflozin on postprandial hypoglycaemia after gastric bypass.
INTRODUCTION
Postprandial hypoglycaemia after gastric bypass surgery (also known as postbariatric hypoglycaemia or PBH) is an increasingly encountered clinical problem. PBH is characterised by meal-induced rapid spikes and consequent falls in glycaemia, resulting in both hypoglycaemia burden and high glycaemic variability. Despite its frequency, there is currently no approved pharmacotherapy. The purpose of this investigation is to evaluate efficacy and safety of empagliflozin 25âmg, a sodium-glucose cotransporter 2-inhibitor, to reduce glucose excursions and hypoglycaemia burden in patients with PBH after gastric bypass surgery.
METHODS AND ANALYSIS
In a prospective, single-centre, randomised, double-blind, placebo-controlled, crossover trial, we plan to enrol 22 adults (â„18 years) with PBH after Roux-en-Y gastric bypass surgery (plasma or sensor glucose <3.0âmmol/L). Eligible patients will be randomised to receive empagliflozin 25âmg and placebo once daily, each for 20 days, in random order. Study periods will be separated by a 2-6âweeks wash-out period. The primary efficacy outcome will be the amplitude of plasma glucose excursion (peak to nadir) during a mixed meal tolerance test. Results will be presented as paired-differences±SD plus 95% CIs with p values and hypothesis testing for primary and secondary outcomes according to intention-to-treat. Secondary outcomes include continuous glucose monitoring-based outcomes, further metabolic measures and safety.
ETHICS AND DISSEMINATION
The DEEP-EMPA trial (original protocol title: Randomized, double-blind, placebo-controlled crossover trialassessing the impact of the SGLT2 inhibitor empagliflozin onpostprandial hypoglycaemia after gastric bypass) was approved by the Bern Ethics Committee (ID 2021-01187) and Swissmedic (Ref. Number: 102663190) in October and November 2021, respectively. First results are expected in the first quarter of 2023 and will be disseminated via peer-reviewed publications and presented at national and international conferences. The acronym DEEP was derived from an overarching project title (DEciphering the Enigma of Postprandial Hyperinsulinaemic Hypoglycaemia after Bariatric Surgery), the term EMPA stands for the drug empagliflozin.
TRIAL REGISTRATION NUMBER
NCT05057819
Tissue engineering in cardiovascular surgery: MTT, a rapid and reliable quantitative method to assess the optimal human cell seeding on polymeric meshes
Objective: Currently used valve substitutes for valve replacement have certain disadvantages that limit their long-term benefits such as poor durability, risks of infection, thromboebolism or rejection. A tissue engineered autologous valve composed of living tissue is expected to overcome these shortcomings with natural existing biological mechanisms for growth, repair, remodeling and development. The aim of the study was to improve cell seeding methods for developing tissue-engineered valve tissue. Methods: Human aortic myofibroblasts were seeded on polyglycolic acid (PGA) meshes. Cell attachment and growth of myofibroblasts on the PGA scaffolds with different seeding intervals were compared to determine an optimal seeding interval. In addition, scanning electron microscopy study of the seeded meshes was also performed to document tissue development. Results: There was a direct correlation between cell numbers assessed by direct counting and MTT(3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltertra-zolium bromide) assay. Both attach rate and cell growth seeded on meshes with long intervals (24 and 36 h) were significantly higher than those seeded with short intervals (2 and 12 h) (PâȘ0.01), there was no significant difference between 24- and 36-h seeding interval. Scanning electron microscopy also documented more cell attachment with long seeding intervals resulting in a more solid tissue like structure. Conclusion: It is feasible to use human aortic myofibroblasts to develop a new functional tissue in vitro. Twenty-four hours is an optimal seeding interval for seeding human aortic myofibroblasts on PGA scaffolds and MTT test is a rapid and reliable quantitative method to assess the optimal human cell seeding on polymeric meshe
Tissue engineering in cardiovascular surgery: MTT, a rapid and reliable quantitative method to assess the optimal human cell seeding on polymeric meshes1
Objective: Currently used valve substitutes for valve replacement have certain disadvantages that limit their long-term benefits such as poor durability, risks of infection, thromboebolism or rejection. A tissue engineered autologous valve composed of living tissue is expected to overcome these shortcomings with natural existing biological mechanisms for growth, repair, remodeling and development. The aim of the study was to improve cell seeding methods for developing tissue-engineered valve tissue. Methods: Human aortic myofibroblasts were seeded on polyglycolic acid (PGA) meshes. Cell attachment and growth of myofibroblasts on the PGA scaffolds with different seeding intervals were compared to determine an optimal seeding interval. In addition, scanning electron microscopy study of the seeded meshes was also performed to document tissue development. Results: There was a direct correlation between cell numbers assessed by direct counting and MTT(3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltertra-zolium bromide) assay. Both attach rate and cell growth seeded on meshes with long intervals (24 and 36 h) were significantly higher than those seeded with short intervals (2 and 12 h) (PâȘ0.01), there was no significant difference between 24- and 36-h seeding interval. Scanning electron microscopy also documented more cell attachment with long seeding intervals resulting in a more solid tissue like structure. Conclusion: It is feasible to use human aortic myofibroblasts to develop a new functional tissue in vitro. Twenty-four hours is an optimal seeding interval for seeding human aortic myofibroblasts on PGA scaffolds and MTT test is a rapid and reliable quantitative method to assess the optimal human cell seeding on polymeric meshe
Pioglitazone Prevents Capillary Rarefaction in Streptozotocin-Diabetic Rats Independently of Glucose Control and Vascular Endothelial Growth Factor Expression
Background/Aims: Reduction of capillary network density occurs early in the development of metabolic syndrome and may be relevant for the precipitation of diabetes. Agonists of the peroxisome proliferator-activated receptor (PPAR)-gamma transcription factor are vasculoprotective, but their capacity for structural preservation of the microcirculation is unclear. Methods: Male Wistar rats were rendered diabetic by streptozotocin and treated with pioglitazone in chow for up to 12 weeks. Capillary density was determined in heart and skeletal muscle after platelet endothelial cell adhesion molecule-1 (PECAM-1) immunostaining. Hallmarks of apoptosis and angiogenesis were determined. Results: Capillary density deteriorated progressively in the presence of hyperglycemia (from 971/mm(2) to 475/mm(2) in quadriceps muscle during 13 weeks). Pioglitazone did not influence plasma glucose, left ventricular weight, or body weight but nearly doubled absolute and relative capillary densities compared to untreated controls (1.2 vs. 0.6 capillaries/myocyte in heart and 1.5 vs. 0.9 capillaries/myocyte in quadriceps muscle) after 13 weeks of diabetes. No antiapoptotic or angiogenic influence of pioglitazone was detected while a reduced expression of hypoxia-inducible factor-3 alpha and PPAR coactivator-1 alpha (PGC-1 alpha) mRNA as well as vascular endothelial growth factor (VEGF) protein possibly occurred as a consequence of improved vascularization. Conclusion: Pioglitazone preserves microvascular structure in diabetes independently of improvements in glycemic control and by a mechanism unrelated to VEGF-mediated angiogenesis. Copyright (C) 2012 S. Karger AG, Base
Endothelial- and Platelet-Derived Microparticles Are Generated During Liver Resection in Humans
BACKGROUND
Cell-derived plasma microparticles (<1.5Â ÎŒm) originating from various cell types have the potential to regulate thrombogenesis and inflammatory responses. The aim of this study was to test the hypothesis that microparticles generated during hepatic surgery co-regulate postoperative procoagulant and proinflammatory events.
METHODS
In 30 patients undergoing liver resection, plasma microparticles were isolated, quantitated, and characterized as endothelial (CD31+, CD41-), platelet (CD41+), or leukocyte (CD11b+) origin by flow cytometry and their procoagulant and proinflammatory activity was measured by immunoassays.
RESULTS
During liver resection, the total numbers of microparticles increased with significantly more Annexin V-positive, endothelial and platelet-derived microparticles following extended hepatectomy compared to standard and minor liver resections. After liver resection, microparticle tissue factor and procoagulant activity increased along with overall coagulation as assessed by thrombelastography. Levels of leukocyte-derived microparticles specifically increased in patients with systemic inflammation as assessed by C-reactive protein but are independent of the extent of liver resection.
CONCLUSIONS
Endothelial and platelet-derived microparticles are specifically elevated during liver resection, accompanied by increased procoagulant activity. Leukocyte-derived microparticles are a potential marker for systemic inflammation. Plasma microparticles may represent a specific response to surgical stress and may be an important mediator of postoperative coagulation and inflammation
Dayâtoâday variability of insulin requirements in the inpatient setting: Observations during fully closedâloop insulin delivery
Funder: and the Swiss Diabetes FoundationAbstract: The aim of this study was to characterize the variability of exogenous insulin requirements during fully closedâloop insulin delivery in hospitalized patients with type 2 diabetes or newâonset hyperglycaemia, and to determine patientârelated characteristics associated with higher variability of insulin requirements. We retrospectively analysed data from two fully closedâloop inpatient studies involving adults with type 2 diabetes or newâonset hyperglycaemia requiring insulin therapy. The coefficient of variation quantified dayâtoâday variability of exogenous insulin requirements during up to 15 days using fully automated closedâloop insulin delivery. Data from 535 days in 67 participants were analysed. The coefficient of variation of dayâtoâday exogenous insulin requirements was 30% ± 16%, and was higher between nights than between any daytime period (56% ± 29% overnight [11:00 pm to 4:59 am] compared with 41% ± 21% in the morning [5:00 am to 10:59 am], 39% ± 15% in the afternoon [11:00 am to 4:59 pm] and 45% ± 19% during the evening [5:00 pm to 10:59 pm]; all P < 0.01). There is high dayâtoâday variability of exogenous insulin requirements in inpatients, particularly overnight, and diabetes management approaches should account for this variability
Recommended from our members
Fully closed-loop insulin delivery in inpatients receiving nutritional support: a two-centre, open-label, randomised controlled trial.
BACKGROUND: Glucose management is challenging in patients who require nutritional support in hospital. We aimed to assess whether fully closed-loop insulin delivery would improve glycaemic control compared with conventional subcutaneous insulin therapy in inpatients receiving enteral or parenteral nutrition or both. METHODS: We did a two-centre (UK and Switzerland), open-label, randomised controlled trial in adult inpatients receiving enteral or parenteral nutrition (or both) who required subcutaneous insulin therapy. Patients recruited from non-critical care surgical and medical wards were randomly assigned (1:1) using a computer-generated minimisation schedule (stratified by type of nutritional support [parenteral nutrition on or off] and pre-study total daily insulin dose [<50 or â„50 units]) to receive fully closed-loop insulin delivery with faster-acting insulin aspart (closed-loop group) or conventional subcutaneous insulin therapy (control group) given in accordance with local clinical practice. Continuous glucose monitoring in the control group was masked to patients, ward staff, and investigators. Patients were followed up for a maximum of 15 days or until hospital discharge. The primary endpoint was the proportion of time that sensor glucose concentration was in target range (5·6-10·0 mmol/L), assessed in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, number NCT01774565. FINDINGS: Between Feb 8, 2018, and Sept 21, 2018, 90 patients were assessed for eligibility, of whom 43 were enrolled and randomly assigned to the closed-loop group (n=21) or the control group (n=22). The proportion of time that sensor glucose was in the target range was 68·4% [SD 15·5] in the closed-loop group and 36·4% [26·6] in the control group (difference 32·0 percentage points [95% CI 18·5-45·5; p<0·0001]). One serious adverse event occurred in each group (one cardiac arrest in the control group and one episode of acute respiratory failure in the closed-loop group), both of which were unrelated to study interventions. There were no adverse events related to study interventions in either group. No episodes of severe hypoglycaemia or hyperglycaemia with ketonaemia occurred in either study group. INTERPRETATION: Closed-loop insulin delivery is an effective treatment option to improve glycaemic control in patients receiving nutritional support in hospital. FUNDING: Diabetes UK, Swiss National Science Foundation, National Institute for Health Research Cambridge Biomedical Research Centre, Wellcome Trust, and European Foundation for the Study of Diabetes
The Fifth Data Release of the Sloan Digital Sky Survey
This paper describes the Fifth Data Release (DR5) of the Sloan Digital Sky
Survey (SDSS). DR5 includes all survey quality data taken through June 2005 and
represents the completion of the SDSS-I project (whose successor, SDSS-II will
continue through mid-2008). It includes five-band photometric data for 217
million objects selected over 8000 square degrees, and 1,048,960 spectra of
galaxies, quasars, and stars selected from 5713 square degrees of that imaging
data. These numbers represent a roughly 20% increment over those of the Fourth
Data Release; all the data from previous data releases are included in the
present release. In addition to "standard" SDSS observations, DR5 includes
repeat scans of the southern equatorial stripe, imaging scans across M31 and
the core of the Perseus cluster of galaxies, and the first spectroscopic data
from SEGUE, a survey to explore the kinematics and chemical evolution of the
Galaxy. The catalog database incorporates several new features, including
photometric redshifts of galaxies, tables of matched objects in overlap regions
of the imaging survey, and tools that allow precise computations of survey
geometry for statistical investigations.Comment: ApJ Supp, in press, October 2007. This paper describes DR5. The SDSS
Sixth Data Release (DR6) is now public, available from http://www.sdss.or
The Seventh Data Release of the Sloan Digital Sky Survey
This paper describes the Seventh Data Release of the Sloan Digital Sky Survey
(SDSS), marking the completion of the original goals of the SDSS and the end of
the phase known as SDSS-II. It includes 11663 deg^2 of imaging data, with most
of the roughly 2000 deg^2 increment over the previous data release lying in
regions of low Galactic latitude. The catalog contains five-band photometry for
357 million distinct objects. The survey also includes repeat photometry over
250 deg^2 along the Celestial Equator in the Southern Galactic Cap. A
coaddition of these data goes roughly two magnitudes fainter than the main
survey. The spectroscopy is now complete over a contiguous area of 7500 deg^2
in the Northern Galactic Cap, closing the gap that was present in previous data
releases. There are over 1.6 million spectra in total, including 930,000
galaxies, 120,000 quasars, and 460,000 stars. The data release includes
improved stellar photometry at low Galactic latitude. The astrometry has all
been recalibrated with the second version of the USNO CCD Astrograph Catalog
(UCAC-2), reducing the rms statistical errors at the bright end to 45
milli-arcseconds per coordinate. A systematic error in bright galaxy photometr
is less severe than previously reported for the majority of galaxies. Finally,
we describe a series of improvements to the spectroscopic reductions, including
better flat-fielding and improved wavelength calibration at the blue end,
better processing of objects with extremely strong narrow emission lines, and
an improved determination of stellar metallicities. (Abridged)Comment: 20 pages, 10 embedded figures. Accepted to ApJS after minor
correction
- âŠ