2,732 research outputs found
A comparison of the domestic satellite communications forecast to the year 2000
The methodologies and results of three NASA-sponsored market demand assessment studies are presented and compared. Forecasts of future satellite addressable traffic (both trunking and customer premises services) were developed for the three main service categories of voice, data and video and subcategories thereof for the benchmark years of 1980, 1990 and 2000. The contractor results are presented on a service by service basis in two formats: equivalent 36 MHz transponders and basic transmission units (voice: half-voice circuits, data: megabits per second and video: video channels). It is shown that while considerable differences exist at the service category level, the overall forecasts by the two contractors are quite similar. ITT estimates the total potential satellite market to be 3594 transponders in the year 2000 with data service comprising 54 percent of this total. The WU outlook for the same time period is 2779 transponders with voice services accounting for 66 percent of the total
Human cytomegalovirus inhibits apoptosis by proteasome-mediated degradation of bax at endoplasmic reticulum-mitochondrion contacts
Human cytomegalovirus (HCMV) encodes the UL37 exon 1 protein (pUL37x1), which is the potent viral mitochondrion-localized inhibitor of apoptosis (vMIA), to increase survival of infected cells. HCMV vMIA traffics from the endoplasmic reticulum (ER) to ER subdomains, which are physically linked to mitochondria known as mitochondrion-associated membranes (MAM), and to mitochondria. The antiapoptotic function of vMIA is thought to primarily result from its ability to inhibit Bax-mediated permeabilization of the outer mitochondrial membrane (OMM). Here, we establish that vMIA retargets Bax to the MAM as well as to the OMM from immediate early through late times of infection. However, MAM localization of Bax results in its increased ubiquitination and proteasome-mediated degradation. Surprisingly, HCMV infection does not increase OMM-associated degradation (OMMAD) of Bax, even though the ER and mitochondria are physically connected at the MAM. It was recently found that lipid rafts at the plasma membrane can connect extrinsic and intrinsic apoptotic pathways and can serve as sites of apoptosome assembly. In transfected permissive human fibroblasts, vMIA mediates, through its cholesterol affinity, association of Bax and apoptosome components with MAM lipid rafts. While Bax association with MAM lipid rafts was detected in HCMV-infected cells, association of apoptosome components was not. These results establish that Bax recruitment to the MAM and its MAM-associated degradation (MAMAD) are a newly described antiapoptotic mechanism used by HCMV infection to increase cell survival for its growth
The hospital costs associated with acute paediatric burn injuries
Background. Ongoing rationing of healthcare threatens services that are well established, and cripples others that desperately require investment. Burn, for one, remains a neglected epidemic in South Africa (SA), despite the magnitude of the problem.Objective. To identify the prominent components contributing to the cost of hospital admission with paediatric burn injury. Determining the true costs of specialist services is important, so that resources can be allocated appropriately to achieve the greatest possible impact.Methods. A retrospective study was undertaken over 1 year to determine patient demographics and injury details of 987 patients admitted with burn injuries to Red Cross War Memorial Children’s Hospital, Cape Town, SA. The in-hospital financial records of 80 randomly selected patients were examined. This was followed by a prospective study to determine the financial implications of four cost drivers, i.e. bed cost per day, costs of medications received, costs of dressings for wound care, and costs of surgical intervention. A random selection of 37 dressing changes (in 31 paediatric patients) and 19 surgical interventions was observed, during which all costs were recorded.Results. As expected, severe flame burns are responsible for more prolonged hospital stays and usually require surgical intervention. Scald burns comprise the greatest proportion of burn injuries, and therefore account for a considerable part of the hospital’s expenditure towards burn care.Conclusion. While community programmes aiming to prevent burn injuries are important, this study motivates for the implementation of accessible ambulatory services in low-income areas. This strategy would enable the burn unit to reduce its costs by limiting unnecessary admissions, and prioritising its resources for those with more severe burn injuries
Regulation of the subcellular distribution of key cellular RNA-processing factors during permissive human cytomegalovirus infection
Alternative splicing and polyadenylation of human cytomegalovirus (HCMV) immediate-early (IE) pre-mRNAs are temporally regulated and rely on cellular RNA-processing factors. This study examined the location and abundance of essential RNA-processing factors, which affect alternative processing of UL37 IE pre-mRNAs, during HCMV infection. Serine/threonine protein kinase 1 (SRPK1) phosphorylates serine/arginine-rich proteins, necessary for pre-spliceosome commitment. It was found that HCMV infection progressively increased the abundance of cytoplasmic SRPK1, which is regulated by subcellular partitioning. The essential polyadenylation factor CstF-64 was similarly increased in abundance, albeit in the nucleus, proximal to and within viral replication compartments (VRCs). In contrast, the location of polypyrimidine tract-binding protein (PTB), known to adversely affect splicing of HCMV major IE RNAs, was temporally regulated during infection. PTB co-localized with CstF-64 in the nucleus at IE times. By early times, PTB was detected in punctate cytoplasmic sites of some infected cells. At late times, PTB relocalized to the nucleus, where it was notably excluded from HCMV VRCs. Moreover, HCMV infection induced the formation of nucleolar stress structures, fibrillarin-containing caps, in close proximity to its VRCs. PTB exclusion from HCMV VRCs required HCMV DNA synthesis and/or late gene expression, whereas the regulation of SRPK1 subcellular distribution did not. Taken together, these results indicated that HCMV increasingly regulates the subcellular distribution and abundance of essential RNA-processing factors, thereby altering their ability to affect the processing of viral pre-mRNAs. These results further suggest that HCMV infection selectively induces sorting of nucleolar and nucleoplasmic components
The hospital costs associated with acute paediatric burn injuries
__Background__ Ongoing rationing of healthcare threatens services that are well established, and cripples others that desperately require investment. Burn, for one, remains a neglected epidemic in South Africa (SA), despite the magnitude of the problem.
__Objective__ To identify the prominent components contributing to the cost of hospital admission with paediatric burn injury. Determining the true costs of specialist services is important, so that resources can be allocated appropriately to achieve the greatest possible impact.
__Methods__ A retrospective study was undertaken over 1 year to determine patient demographics and injury details of 987 patients admitted with burn injuries to Red Cross War Memorial Children’s Hospital, Cape Town, SA. The in-hospital financial records of 80 randomly selected patients were examined. This was followed by a prospective study to determine the financial implications of four cost drivers, i.e. bed cost per day, costs of medications received, costs of dressings for wound care, and costs of surgical intervention. A random selection of 37 dressing changes (in 31 p
Enabling Technologies for Silicon Microstrip Tracking Detectors at the HL-LHC
While the tracking detectors of the ATLAS and CMS experiments have shown
excellent performance in Run 1 of LHC data taking, and are expected to continue
to do so during LHC operation at design luminosity, both experiments will have
to exchange their tracking systems when the LHC is upgraded to the
high-luminosity LHC (HL-LHC) around the year 2024. The new tracking systems
need to operate in an environment in which both the hit densities and the
radiation damage will be about an order of magnitude higher than today. In
addition, the new trackers need to contribute to the first level trigger in
order to maintain a high data-taking efficiency for the interesting processes.
Novel detector technologies have to be developed to meet these very challenging
goals. The German groups active in the upgrades of the ATLAS and CMS tracking
systems have formed a collaborative "Project on Enabling Technologies for
Silicon Microstrip Tracking Detectors at the HL-LHC" (PETTL), which was
supported by the Helmholtz Alliance "Physics at the Terascale" during the years
2013 and 2014. The aim of the project was to share experience and to work
together on key areas of mutual interest during the R&D phase of these
upgrades. The project concentrated on five areas, namely exchange of
experience, radiation hardness of silicon sensors, low mass system design,
automated precision assembly procedures, and irradiations. This report
summarizes the main achievements
Prototyping of petalets for the Phase-II Upgrade of the silicon strip tracking detector of the ATLAS Experiment
In the high luminosity era of the Large Hadron Collider, the HL-LHC, the
instantaneous luminosity is expected to reach unprecedented values, resulting
in about 200 proton-proton interactions in a typical bunch crossing. To cope
with the resultant increase in occupancy, bandwidth and radiation damage, the
ATLAS Inner Detector will be replaced by an all-silicon system, the Inner
Tracker (ITk). The ITk consists of a silicon pixel and a strip detector and
exploits the concept of modularity. Prototyping and testing of various strip
detector components has been carried out. This paper presents the developments
and results obtained with reduced-size structures equivalent to those foreseen
to be used in the forward region of the silicon strip detector. Referred to as
petalets, these structures are built around a composite sandwich with embedded
cooling pipes and electrical tapes for routing the signals and power. Detector
modules built using electronic flex boards and silicon strip sensors are glued
on both the front and back side surfaces of the carbon structure. Details are
given on the assembly, testing and evaluation of several petalets. Measurement
results of both mechanical and electrical quantities are shown. Moreover, an
outlook is given for improved prototyping plans for large structures.Comment: 22 pages for submission for Journal of Instrumentatio
Music to prevent deliriUm during neuroSurgerY (MUSYC) Clinical trial:A study protocol for a randomised controlled trial
INTRODUCTION: Delirium is a neurocognitive disorder characterised by an acute and temporary decline of mental status affecting attention, awareness, cognition, language and visuospatial ability. The underlying pathophysiology is driven by neuroinflammation and cellular oxidative stress. Delirium is a serious complication following neurosurgical procedures with a reported incidence varying between 4% and 44% and has been associated with increased length of hospital stay, increased amount of reoperations, increased costs and mortality. Perioperative music has been reported to reduce preoperative anxiety, postoperative pain and opioid usage, and attenuates stress response caused by surgery. We hypothesize that this beneficial effect of music on a combination of delirium eliciting factors might reduce delirium incidence following neurosurgery and subsequently improve clinical outcomes. METHODS: This protocol concerns a single-centred prospective randomised controlled trial with 6 months follow-up. All adult patients undergoing a craniotomy at the Erasmus Medical Center in Rotterdam are eligible. The music group will receive recorded music through an overear headphone before, during and after surgery until postoperative day 3. Patients can choose from music playlists, offered based on music importance questionnaires administered at baseline. The control group will receive standard of clinical care Delirium is assessed by the Delirium Observation Scale and confirmed by a delirium-expert psychiatrist according to the DSM-5 criteria. Risk factors correlated with the onset of delirium, such as cognitive function at baseline, preoperative anxiety, perioperative medication use, depth of anaesthesia and postoperative pain, and delirium-related health outcomes such as length of stay, daily function, quality of life (ie, EQ-5D, EORTC questionnaires), costs and cost-effectiveness are collected. ETHICS AND DISSEMINATION: This study is being conducted in accordance with the Declaration of Helsinki. The Medical Ethics Review Board of Erasmus University Medical Center Rotterdam, The Netherlands, approved this protocol. Results will be disseminated via peer-reviewed scientific journals and conference presentations. TRIAL REGISTRATION NUMBERS: NL8503 and NCT04649450
Investigations into the impact of locally modified sensor architectures on the detection efficiency of silicon micro-strip sensors
The High Luminosity Upgrade of the LHC will require the replacement of the Inner Detector of ATLAS with the Inner Tracker (ITk) in order to cope with higher radiation levels and higher track densities. Prototype silicon strip detector modules are currently developed and their performance is studied in both particle test beams and X-ray beams. In previous test beam measurements of prototype modules, the response of silicon sensors has been studied in detailed scans across individual sensor strips. These scans found instances of sensor strips collecting charge across areas on the sensor deviating from the geometrical width of a sensor strip. The variations have been linked to local features of the sensor architecture. This paper presents results of detailed sensor measurements in both X-ray and particle beams investigating the impact of sensor features (metal pads and p-stops) on the sensor strip response
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