During the dawn of chemistry
, when the temperature of the young Universe had fallen below some 4,000 kelvin, the ions of the light elements produced in Big Bang nucleosynthesis recombined in reverse ...order of their ionization potential. With their higher ionization potentials, the helium ions He
and He
were the first to combine with free electrons, forming the first neutral atoms; the recombination of hydrogen followed. In this metal-free and low-density environment, neutral helium atoms formed the Universe's first molecular bond in the helium hydride ion HeH
through radiative association with protons. As recombination progressed, the destruction of HeH
created a path to the formation of molecular hydrogen. Despite its unquestioned importance in the evolution of the early Universe, the HeH
ion has so far eluded unequivocal detection in interstellar space. In the laboratory the ion was discovered
as long ago as 1925, but only in the late 1970s was the possibility that HeH
might exist in local astrophysical plasmas discussed
. In particular, the conditions in planetary nebulae were shown to be suitable for producing potentially detectable column densities of HeH
. Here we report observations, based on advances in terahertz spectroscopy
and a high-altitude observatory
, of the rotational ground-state transition of HeH
at a wavelength of 149.1 micrometres in the planetary nebula NGC 7027. This confirmation of the existence of HeH
in nearby interstellar space constrains our understanding of the chemical networks that control the formation of this molecular ion, in particular the rates of radiative association and dissociative recombination.
No distinctive clinical signs of Ebola virus disease (EVD) have prompted the development of rapid screening tools or called for a new approach to screening suspected Ebola cases. New screening ...approaches require evidence of clinical benefit and economic efficiency. As of now, no evidence or defined algorithm exists.
To evaluate, from a healthcare perspective, the efficiency of incorporating Ebola prediction scores and rapid diagnostic tests into the EVD screening algorithm during an outbreak.
We collected data on rapid diagnostic tests (RDTs) and prediction scores' accuracy measurements, e.g., sensitivity and specificity, and the cost of case management and RDT screening in EVD suspect cases. The overall cost of healthcare services (PPE, procedure time, and standard-of-care (SOC) costs) per suspected patient and diagnostic confirmation of EVD were calculated. We also collected the EVD prevalence among suspects from the literature. We created an analytical decision model to assess the efficiency of eight screening strategies: 1) Screening suspect cases with the WHO case definition for Ebola suspects, 2) Screening suspect cases with the ECPS at -3 points of cut-off, 3) Screening suspect cases with the ECPS as a joint test, 4) Screening suspect cases with the ECPS as a conditional test, 5) Screening suspect cases with the WHO case definition, then QuickNavi™-Ebola RDT, 6) Screening suspect cases with the ECPS at -3 points of cut-off and QuickNavi™-Ebola RDT, 7) Screening suspect cases with the ECPS as a conditional test and QuickNavi™-Ebola RDT, and 8) Screening suspect cases with the ECPS as a joint test and QuickNavi™-Ebola RDT. We performed a cost-effectiveness analysis to identify an algorithm that minimizes the cost per patient correctly classified. We performed a one-way and probabilistic sensitivity analysis to test the robustness of our findings.
Our analysis found dual ECPS as a conditional test with the QuickNavi™-Ebola RDT algorithm to be the most cost-effective screening algorithm for EVD, with an effectiveness of 0.86. The cost-effectiveness ratio was 106.7 USD per patient correctly classified. The following algorithms, the ECPS as a conditional test with an effectiveness of 0.80 and an efficiency of 111.5 USD per patient correctly classified and the ECPS as a joint test with the QuickNavi™-Ebola RDT algorithm with an effectiveness of 0.81 and a cost-effectiveness ratio of 131.5 USD per patient correctly classified. These findings were sensitive to variations in the prevalence of EVD in suspected population and the sensitivity of the QuickNavi™-Ebola RDT.
Findings from this study showed that prediction scores and RDT could improve Ebola screening. The use of the ECPS as a conditional test algorithm and the dual ECPS as a conditional test and then the QuickNavi™-Ebola RDT algorithm are the best screening choices because they are more efficient and lower the number of confirmation tests and overall care costs during an EBOV epidemic.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
IntroductionAn effective rifampicin-resistant tuberculosis (RR-TB) treatment regimen should include prevention of resistance amplification. While bedaquiline (BDQ) has been recommended in all-oral ...RR-TB treatment regimen since 2019, resistance is rising at alarming rates. This may be due to BDQ’s delayed bactericidal effect, which increases the risk of selecting for resistance to fluoroquinolones and/or BDQ in the first week of treatment when the bacterial load is highest. We aim to strengthen the first week of treatment with the injectable drug amikacin (AMK). To limit the ototoxicity risk while maximising the bactericidal effect, we will evaluate the safety of adding a 30 mg/kg AMK injection on the first and fourth day of treatment.Methods and analysisWe will conduct a single-arm clinical trial on 20 RR-TB patients nested within an operational study called ShoRRT (All oral Shorter Treatment Regimen for Drug resistant Tuberculosis). In addition to all-oral RR-TB treatment, patients will receive two doses of AMK. The primary safety endpoint is any grade 3–4 adverse event during the first 2 weeks of treatment related to the use of AMK. With a sample size of 20 patients, we will have at least 80% statistical power to support the alternative hypothesis, indicating that less than 14% of patients treated with AMK experience a grade 3–4 adverse event related to its use. Safety data obtained from this study will inform a larger multicountry study on using two high doses of AMK to prevent acquired resistance.Ethics and disseminationApproval was obtained from the ethics committee of Rwanda, Rwanda Food and Drug Authority, Universitair Ziekenhuis, the Institute of Tropical Medicine ethics review board. All participants will provide informed consent. Study results will be disseminated through peer-reviewed journals and conferences.Trial registration number NCT05555303.
ABSTRACT
We have mapped the NGC 2023 reflection nebula in the 63 and 145 $\mu$m transitions of O i and the 158 $\mu$m C ii spectral lines using the heterodyne receiver upGREAT on SOFIA. The ...observations were used to identify the diffuse and dense components of the photon-dominated region (PDR) traced by the C ii and O i emission, respectively. The velocity-resolved observations reveal the presence of a significant column of low-excitation atomic oxygen, seen in absorption in the O i 63 $\mu$m spectra, amounting to about 20–60 per cent of the oxygen column seen in emission in the O i 145 $\mu$m spectra. Some self-absorption is also seen in C ii, but for the most part it is hardly noticeable. The C ii and O i 63 $\mu$m spectra show strong red- and blue-shifted wings due to photoevaporation flows especially in the south-eastern and southern part of the reflection nebula, where comparison with the mid- and high-J CO emission indicates that the C+ region is expanding into a dense molecular cloud. Using a two-slab toy model the large-scale self-absorption seen in O i 63 $\mu$m is readily explained as originating in foreground low-excitation gas associated with the source. Similar columns have also been observed recently in other Galactic PDRs. These results have two implications: for the velocity-unresolved extragalactic observations this could impact the use of O i 63 $\mu$m as a tracer of massive star formation and secondly, the widespread self-absorption in O i 63 $\mu$m leads to underestimate of the column density of atomic oxygen derived from this tracer and necessitates the use of alternative indirect methods.
During the dawn of chemistry.sup.1,2, when the temperature of the young Universe had fallen below some 4,000 kelvin, the ions of the light elements produced in Big Bang nucleosynthesis recombined in ...reverse order of their ionization potential. With their higher ionization potentials, the helium ions He.sup.2+ and He.sup.+ were the first to combine with free electrons, forming the first neutral atoms; the recombination of hydrogen followed. In this metal-free and low-density environment, neutral helium atoms formed the Universe's first molecular bond in the helium hydride ion HeH.sup.+ through radiative association with protons. As recombination progressed, the destruction of HeH.sup.+ created a path to the formation of molecular hydrogen. Despite its unquestioned importance in the evolution of the early Universe, the HeH.sup.+ ion has so far eluded unequivocal detection in interstellar space. In the laboratory the ion was discovered.sup.3 as long ago as 1925, but only in the late 1970s was the possibility that HeH.sup.+ might exist in local astrophysical plasmas discussed.sup.4-7. In particular, the conditions in planetary nebulae were shown to be suitable for producing potentially detectable column densities of HeH.sup.+. Here we report observations, based on advances in terahertz spectroscopy.sup.8,9 and a high-altitude observatory.sup.10, of the rotational ground-state transition of HeH.sup.+ at a wavelength of 149.1 micrometres in the planetary nebula NGC 7027. This confirmation of the existence of HeH.sup.+ in nearby interstellar space constrains our understanding of the chemical networks that control the formation of this molecular ion, in particular the rates of radiative association and dissociative recombination.
In the past decade tens of millions of dollars have been spent by water resource agencies in California to restore the native salmon fishery in the San Joaquin River and its major tributaries. An ...excavated deep water ship channel (DWSC), through which the river runs on its way to the Bay/Delta and Pacific Ocean, experiences episodes of low dissolved oxygen which acts as a barrier to anadromous fish migration and a threat to the long-term survival of the salmon run. An emergency response management system is under development to forecast these episodes of low dissolved oxygen and to deploy measures that will raise dissolved oxygen concentrations to prevent damage to the fishery resource. The emergency response management system has been designed to interact with a real-time water quality monitoring network and is served by a comprehensive data management and forecasting model toolbox. The Bay/Delta and Tributaries (BDAT) Cooperative Data Management System is a distributed, web accessible database that contains terabytes of information on all aspects of the ecology of the Bay/Delta and upper watersheds. The complexity of the problem dictates data integration from a variety of monitoring programs. A unique data templating system has been constructed to serve the needs of cooperating scientists who wish to share their data and to simplify and streamline data uploading into the master database. In this paper we demonstrate the utility of such a system in providing decision support for management of the San Joaquin River fishery. We discuss how the system might be expanded to have further utility in coping with other emergencies and threats to water supply system serving California's costal communities.
Due to advancements in ultrasound techniques, the focus of antenatal ultrasound screening is moving towards the first trimester of pregnancy. The early first trimester however remains in part, a ...‘black box’, due to the size of the developing embryo and the limitations of contemporary scanning techniques. Therefore there is a need for images of early anatomical developmental to improve our understanding of this area. By using new imaging techniques, we can not only obtain better images to further our knowledge of early embryonic development, but clear images of embryonic and fetal development can also be used in training for e.g. sonographers and fetal surgeons, or to educate parents expecting a child with a fetal anomaly.
The aim of this review is to provide an overview of the past, present and future techniques used to capture images of the developing human embryo and fetus and provide the reader newest insights in upcoming and promising imaging techniques. The reader is taken from the earliest drawings of da Vinci, along the advancements in the fields of in utero ultrasound and MR imaging techniques towards high-resolution ex utero imaging using Micro-CT and ultra-high field MRI. Finally, a future perspective is given about the use of artificial intelligence in ultrasound and new potential imaging techniques such as synchrotron radiation-based CT to increase our knowledge regarding human development.
Skeletally immature wrists are considered at risk of injury due to increased axial loading through a relatively shorter ulna. The aim of this study was to determine whether triangular fibrocartilage ...thickness relates to ulnar variance and age in adolescents. The radiographs and MRIs of 24 healthy adolescents were retrospectively assessed. Four observers assessed bone age and ulnar variance on radiographs and measured triangular fibrocartilage thickness on MRIs. Median calendar and bone age was 13 years and ulnar variance was −0.7 mm. Median triangular fibrocartilage thickness was 1.4 mm, with excellent inter-observer agreement (r = 0.86). It was moderately correlated with ulnar variance (ρ = −0.46) as well as with bone age (ρ = −0.49). Both variables were statistically significant predictors in a multivariate analysis. This suggests that triangular fibrocartilage thickness changes during skeletal maturation, which might influence axial load distribution in skeletally immature wrists.
Over the last few years, fetal postmortem microfocus computed tomography (micro-CT) imaging has increased in popularity for both diagnostic and research purposes. Micro-CT imaging could be a ...substitute for autopsy, particularly in very early gestation fetuses for whom autopsy can be technically challenging and is often unaccepted by parents. This article provides an overview of the latest research in fetal postmortem micro-CT imaging with a focus on diagnostic accuracy, endovascular staining approaches, placental studies and the reversibility of staining. It also discusses new methods that could prove helpful for micro-CT of larger fetuses. While more research is needed, contrast-enhanced micro-CT has the potential to become a suitable alternative to fetal autopsy. Further research using this novel imaging tool could yield wider applications, such as its practise in imaging rare museum specimens.
Radiative and mechanical feedback of massive stars regulates star formation and galaxy evolution. Positive feedback triggers the creation of new stars by collecting dense shells of gas, while ...negative feedback disrupts star formation by shredding molecular clouds. Although key to understanding star formation, their relative importance is unknown. Here, we report velocity-resolved observations from the SOFIA (Stratospheric Observatory for Infrared Astronomy) legacy program FEEDBACK of the massive star-forming region RCW 120 in the CII 1.9-THz fine-structure line, revealing a gas shell expanding at 15 km/s. Complementary APEX (Atacama Pathfinder Experiment) CO J = 3-2 345-GHz observations exhibit a ring structure of molecular gas, fragmented into clumps that are actively forming stars. Our observations demonstrate that triggered star formation can occur on much shorter time scales than hitherto thought (<0.15 million years), suggesting that positive feedback operates on short time periods.
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