On the behavior of micro-spheres in a hydrogen pellet target

A pellet target produces micro-spheres of different materials, which are used as an internal target for nuclear and particle physics studies. We will describe the pellet hydrogen behavior by means of fluid dynamics and thermodynamics. In particular one aim is to theoretically understand the cooling effect in order to find an effective method to optimize the working conditions of a pellet target. During the droplet formation the evaporative cooling is best described by a multi-droplet diffusion-controlled model, while in vacuum, the evaporation follows the (revised) Hertz-Knudsen formula. Experimental observations compared with calculations clearly indicated the presence of supercooling, the effect of which is discussed as well.Comment: 22 pages, 8 figures (of which two are significantly compressed for easier download

Steady non-ideal detonations in cylindrical sticks of expolsives

Numerical simulations of detonations in cylindrical rate-sticks of highly non-ideal explosives are performed, using a simple model with a weakly pressure dependent rate law and a pseudo-polytropic equation of state. Some numerical issues with such simulations are investigated, and it is shown that very high resolution (hundreds of points in the reaction zone) are required for highly accurate (converged) solutions. High resolution simulations are then used to investigate the qualitative dependences of the detonation driving zone structure on the diameter and degree of confinement of the explosive charge. The simulation results are used to show that, given the radius of curvature of the shock at the charge axis, the steady detonation speed and the axial solution are accurately predicted by a quasi-one-dimensional theory, even for cases where the detonation propagates at speeds significantly below the Chapman-Jouguet speed. Given reaction rate and equation of state models, this quasi-one-dimensional theory offers a significant improvement to Wood-Kirkwood theories currently used in industry

International medical collaboration: lessons from Cuba

Over 50,000 Cuban health professionals are currently working overseas in 67 different countries. They work in conjunction with local health professionals. The majority work in primary care in deprived areas. The aim is to reduce morbidity and mortality but also improve health in the long term by training local health professionals, and building both institutions and a structure to deliver health care alongside educating the local population. Cuba is a small, middle-income country. It has, however, made a significant international contribution in relation to medical collaboration. Cuba’s international collaboration is based on the principles of social justice and equity for all. It has set an example for other countries to emulate

Outcomes Associated with Mechanical CPR Devices

BackgroundIn the U.S. 350,000 out of hospital cardiac arrests(OHCA) occur annually with 90% resulting in mortality. Delivering timely, high-quality CPR is paramount in promoting favorable patient outcomes. Inherent difficulties in providing out of hospital CPR in addition to first responder shortages have increased mechanical CPR(mCPR) device utilization in out of hospital settings. Previous trials were conducted in urban areas and have shown no significant difference in efficacy, but smaller studies identified a greater risk of resuscitation related injuries with mCPR. We hypothesized that in a rural setting, mechanical would be non-inferior to manual CPR for patient survival but would produce more resuscitation related injuries. MethodsThis IRB approved retrospective chart review considered all OHCA with attempted resuscitation by Parkview EMS from 1/1/2022–12/31/2023. Pediatric, pregnant, and Do-Not-Resuscitate patient charts were excluded. Traumatic and hypothermic cardiac arrests were also excluded. Data collection was completed via EMR reports. We collaborated with county coroners to obtain autopsy reports with information regarding resuscitation related injuries. Survivability was the primary outcome with cerebral performance category(CPC) scores and resuscitation related injuries as secondary endpoints. A t-test was used for continuous data. Chi-square, odds ratios, and confidence intervals were used for binary data (p<0.05 for significance). ResultsThere were 160 manual and 21 mCPR patients. Injury data was obtained for 117 manual and 11 mCPR patients. 32/160 (20%) manual CPR patients survived and 1/21 (4%) mCPR patients survived (p=0.089). 22/160 (14%) manual CPR patients had favorable CPC scores compared to 1/21 (4%) mCPR patients (p=0.245). While not statistically significant, survival rates and CPC scores may be clinically significant. mCPR patients experienced splenic maceration, liver laceration, lacerated inferior vena cava, and lacerated pericardium significantly more than manual CPR (p=0.001). ConclusionThe outcomes in this rural cohort demonstrated noninferiority of mCPR in comparison to manual CPR

Pressurized rf cavities in ionizing beams

A muon collider or Higgs factory requires significant reduction of the six dimensional emittance of the beam prior to acceleration. One method to accomplish this involves building a cooling channel using high pressure gas filled radio frequency cavities. The performance of such a cavity when subjected to an intense particle beam must be investigated before this technology can be validated. To this end, a high pressure gas filled radio frequency (rf) test cell was built and placed in a 400 MeV beam line from the Fermilab linac to study the plasma evolution and its effect on the cavity. Hydrogen, deuterium, helium and nitrogen gases were studied. Additionally, sulfur hexafluoride and dry air were used as dopants to aid in the removal of plasma electrons. Measurements were made using a variety of beam intensities, gas pressures, dopant concentrations, and cavity rf electric fields, both with and without a 3 T external solenoidal magnetic field. Energy dissipation per electron-ion pair, electron-ion recombination rates, ion-ion recombination rates, and electron attachment times to SF6 and O-2 were measured.ope

Virtual screening for inhibitors of the human TSLP:TSLPR interaction

The pro-inflammatory cytokine thymic stromal lymphopoietin (TSLP) plays a pivotal role in the pathophysiology of various allergy disorders that are mediated by type 2 helper T cell (Th2) responses, such as asthma and atopic dermatitis. TSLP forms a ternary complex with the TSLP receptor (TSLPR) and the interleukin-7-receptor subunit alpha (IL-7Ra), thereby activating a signaling cascade that culminates in the release of pro-inflammatory mediators. In this study, we conducted an in silico characterization of the TSLP: TSLPR complex to investigate the drugability of this complex. Two commercially available fragment libraries were screened computationally for possible inhibitors and a selection of fragments was subsequently tested in vitro. The screening setup consisted of two orthogonal assays measuring TSLP binding to TSLPR: a BLI-based assay and a biochemical assay based on a TSLP: alkaline phosphatase fusion protein. Four fragments pertaining to diverse chemical classes were identified to reduce TSLP: TSLPR complex formation to less than 75% in millimolar concentrations. We have used unbiased molecular dynamics simulations to develop a Markov state model that characterized the binding pathway of the most interesting compound. This work provides a proof-ofprinciple for use of fragments in the inhibition of TSLP: TSLPR complexation

Substrate Fragmentation for the Design of M. tuberculosis CYP121 Inhibitors.

The cyclo-dipeptide substrates of the essential M. tuberculosis (Mtb) enzyme CYP121 were deconstructed into their component fragments and screened against the enzyme. A number of hits were identified, one of which exhibited an unexpected inhibitor-like binding mode. The inhibitory pharmacophore was elucidated, and fragment binding affinity was rapidly improved by synthetic elaboration guided by the structures of CYP121 substrates. The resulting inhibitors have low micromolar affinity, good predicted physicochemical properties and selectivity for CYP121 over other Mtb P450s. Spectroscopic characterisation of the inhibitors' binding mode provides insight into the effect of weak nitrogen-donor ligands on the P450 heme, an improved understanding of factors governing CYP121-ligand recognition and speculation into the biological role of the enzyme for Mtb.M.E.K. was supported by a Commonwealth (University of Cambridge) Scholarship awarded in conjunction with the Cambridge Commonwealth Trust and Cambridge Overseas Trust. A.G.C. and K.J.M. were supported by grants from the Biotechnology and Biological Sciences Research Council (BBSRC) (grant nos. BB/I019669/1 and BB/I019227/1). We acknowledge the support of the Wellcome Trust (Translation Award GR080083/Z/06).This is the final version of the article. It first appeared from Wiley at http://dx.doi.org/10.1002/cmdc.201600248