The influence of a simple blood transfusion policy on overtransfusion in acute upper gastrointestinal haemorrhage.

Blood transfusion is widely used in the management of acute upper gastrointestinal haemorrhage (AUGIH). Trial data suggests that excessive transfusion may be detrimental, yet overtransfusion remains commonplace. This study reports the impact of introducing a simple cross-match policy in a district general hospital, which resulted in a substantial fall in the prevalence of overtransfusion (odds ratio 0.43; 95% confidence interval 0.19-0.98), with potential patient benefits in terms of rebleeding, and a reduction in the total blood transfused from 162 to 121 units per 100 patients with AUGIH. For the cost of blood alone, this corresponds to projected savings across the NHS in England in excess of £2 million per annum

Status of the NSLS-II Injection System Design

The NSLS-II is a new ultra-bright 3rd generation 3 GeV light source that will be built at Brookhaven National Laboratory. Its design is well under way. The requirements for the compact injector complex, which will continuously provide 3 GeV electrons for top-off injection into the storage ring, are demanding: high reliability, relatively high charge and low losses. The injector consists of a linear accelerator, a full-energy booster, as well as transport lines, and an injection straight section. In this paper we give an overview of the NSLS-II injector, discuss its status, specifications, and the design challenges

VACUUM WINDOW DESIGN FOR HIGH-POWER LASERS.

One of the problems in the high-power lasers design is in outcoupling of a powerful laser beam out of a vacuum volume into atmosphere. Usually the laser device is located inside a vacuum tank. The laser radiation is transported to the outside world through the transparent vacuum window. While considered transparent, some of the light passing through the glass is absorbed and converted to heat. For most applications, these properties are academic curiosities; however, in multi-kilowatt lasers, the heat becomes significant and can lead to a failure. The absorbed power can result in thermal stress, reduction of light transmission and, consequently, window damage. Modern optical technology has developed different types of glass (Silica, BK7, diamond, etc.) that have high thermal conductivity and damage threshold. However, for kilo- and megawatt lasers the issue still remains open. In this paper we present a solution that may relieve the heat load on the output window. We discuss advantages and issues of this particular window design

Generation of Coherent X-Ray Radiation Through Modulation Compression

In this paper, we propose a scheme to generate tunable coherent X-ray radiation for future light source applications. This scheme uses an energy chirped electron beam, a laser modulator, a laser chirper and two bunch compressors to generate a prebunched kilo-Ampere current electron beam from a few tens Ampere electron beam out of a linac. The initial modulation energy wavelength can be compressed by a factor of $1+h_b R_{56}^a$ in phase space, where $h_b$ is the energy bunch length chirp introduced by the laser chirper, $R_{56}^a$ is the momentum compaction factor of the first bunch compressor. As an illustration, we present an example to generate more than 400 MW, 170 attoseconds pulse, 1 nm coherent X-ray radiation using a 60 Ampere electron beam out of the linac and 200 nm laser seed. Both the final wavelength and the radiation pulse length in the proposed scheme are tunable by adjusting the compression factor and the laser parameters

Feasibility study of a hard x-ray FEL oscillator at 3 to 4 GeV based on harmonic lasing and transverse gradient undulator

We studied the feasibility of a hard x-ray FEL oscillator (XFELO) based on a 3 to 4 GeV storage ring considered for the low-emittance upgrade of NSLS-II. We present a more detailed derivation of a formula for the small-gain gain calculation for 3 GeV XFELO published in the proceedings of IPAC'21 [1]. We modified the small-signal low-gain formula developed by K.J. Kim, et.al. [4{6] so that the gain can be derived without taking the \no focusing approximation" and a strong focusing can be applied. In this formula, the gain is cast in the form of a product of two factors with one of them depending only on the harmonic number, undulator period, and gap. Using this factor, we show that it is favorable to use harmonic lasing to achieve hard x-ray FEL working in the small-signal low-gain regime with the medium-energy electron beam (3-4 GeV). Our formula also allows FEL optimization by varying the vertical gradient of the undulator, the vertical dispersion, and the horizontal and vertical focusing, independently. Since a quite high peak current is required for the FEL, the collective effects of beam dynamics in medium-energy synchrotrons significantly affect the electron beam parameters. We carried out a multiple-parameter optimization taking collective effects into account and the result indicates the XFELO is feasible for storage ring energy as low as 3 GeV, with local correction of betatron coupling

Proceedings of Pulsed Magnet Design and Measurement Workshop

The goals of the Workshop are to assess the design of pulsed system at the NSLS-II and establish mitigation strategies for critical issues during development. The focus of the Workshop is on resolving questions related to the set-up of the pulsed magnet laboratory, on measuring the pulsed magnet's current waveforms and fields, and on achieving tight tolerances on the magnet's alignment and field quality

The effect of cocaine on gastric mucosal PGE2, LTC4 and ulcerations

The association between cocaine use and acute gastroduodenal perforation is known. The effect of cocaine and stress on gastric mucosal ulceration and the levels of prostaglandin E2 (PGE2) and leukotriene C4 (LTC4) was studied in 40 Sprague–Dawley rats. Controls received intraperitoneal (i.p.) saline, ten received i.p. cocaine (35 mg/kg), ten were stressed by the cold restraint method, and ten had i.p. cocaine and stress. Cocaine alone did not induce ulceration, but decreased PGE2 levels. Stress alone caused ulceration, but was not associated with a change in either PGE2 or LTC4 levels. When combined with stress, however, cocaine caused a three-fold increase in ulceration and a significant increase in PGE2 and LTC4 levels. Stress may predispose the cocaine addict to loss of gastroduodenal mucosal integrity, which is related to an imbalance of PGE2 and LTC4 synthesis