1,099 research outputs found
Excessive gas exchange impairment during exercise in a subject with a history of bronchopulmonary dysplasia and high altitude pulmonary edema
A 27-year-old male subject (V(O2 max)), 92% predicted) with a history of bronchopulmonary dysplasia (BPD) and a clinically documented case of high altitude pulmonary edema (HAPE) was examined at rest and during exercise. Pulmonary function testing revealed a normal forced vital capacity (FVC, 98.1% predicted) and diffusion capacity for carbon monoxide (D(L(CO)), 91.2% predicted), but significant airway obstruction at rest [forced expiratory volume in 1 sec (FEV(1)), 66.5% predicted; forced expiratory flow at 50% of vital capacity (FEF(50)), 34.3% predicted; and FEV(1) /FVC 56.5%] that was not reversible with an inhaled bronchodilator. Gas exchange worsened from rest to exercise, with the alveolar to arterial P(O2) difference (AaD(O2)) increasing from 0 at rest to 41 mmHg at maximal normoxic exercise (VO(2) = 41.4 mL/kg/min) and from 11 to 31 mmHg at maximal hypoxic exercise (VO(2) = 21.9 mL/kg/min). Arterial P(O2) decreased to 67.8 and 29.9 mmHg at maximal normoxic and hypoxic exercise, respectively. These data indicate that our subject with a history of BPD is prone to a greater degree of exercise-induced arterial hypoxemia for a given VO(2) and F(I(O2)) than healthy age-matched controls, which may increase the subject's susceptibility to high altitude illness
Plasmonic gold helices for the visible range fabricated by oxygen plasma purification of electron beam induced deposits
Electron beam induced deposition (EBID) currently provides the only direct writing technique for truly three-dimensional nanostructures with geometrical features below 50 nm. Unfortunately, the depositions from metal-organic precursors suffer from a substantial carbon content. This hinders many applications, especially in plasmonics where the metallic nature of the geometric surfaces is mandatory. To overcome this problem a post-deposition treatment with oxygen plasma at room temperature was investigated for the purification of gold containing EBID structures. Upon plasma treatment, the structures experience a shrinkage in diameter of about 18 nm but entirely keep their initial shape. The proposed purification step results in a core-shell structure with the core consisting of mainly unaffected EBID material and a gold shell of about 20 nm in thickness. These purified structures are plasmonically active in the visible wavelength range as shown by dark field optical microscopy on helical nanostructures. Most notably, electromagnetic modeling of the corresponding scattering spectra verified that the thickness and quality of the resulting gold shell ensures an optical response equal to that of pure gold nanostructures
Development of a Pneumatic High Speed Nakajima Testing Device
Forming limit diagrams are an essential tool for describing the formability of sheet
materials in the deep-drawing process. Here, the well known and frequently employed
procedures are the Nakajima and the Marciniak-Tests. Whereas these procedures'
standardisation is quite advanced in the quasi-static range, numerous different test
procedures exist in the range of elevated forming speeds. In the first part of this work, an
overview of the various procedures is given for generating forming limit diagrams in the
high speed range. In the second part, a pneumatically operated testing device is
introduced which was developed at the Institute for Material Science for performing
Nakajima-Tests in the high speed range. Using this device, standard specimens can be
dynamically formed according to the Nakajima-Test. The testing device is to be employed
for scientifically exploring the deformation mechanisms operating at very high forming
speeds. The testing device’s mode of functioning is demonstrated by means of forming
discs of an EN AW-6082 aluminium alloy sheet. In doing this, the testing apparatus is
mainly characterised by holding the testing conditions constant during the tests: This
particularly concerns the velocity of the tool for forming the sheet discs
Longitudinal study of the effects of teat condition on the risk of new intramammary infections in dairy cows
Machine milking–induced alterations of teat tissue may impair local defense
mechanisms and increase the risk of new intramammary infections. The objective
of the current study was to assess the influence of short-term and long-term
alterations of teat tissue and infectious status of the udder quarter on the
risk of naturally occurring new intramammary infections, inflammatory
responses, and mastitis. Short-term and long-term changes in teat condition of
right udder quarters of 135 cows of a commercial dairy farm in Saxony-Anhalt,
Germany, were recorded monthly for 10 mo using simple classification schemes.
Quarter milk samples were collected from all examined quarters at each farm
visit. Bacteriological culture results and somatic cell counts of quarter milk
samples were used to determine new inflammatory responses (increase from
≤100,000 cells/mL to >100,000 cells/mL between 2 samples), new infections
(detection of a pathogen from a quarter that was free of the same pathogen at
the preceding sampling), and new mastitis (combination of new inflammatory
response and new infection). Separate Poisson mixed models for new
inflammatory responses, new infections, and new mastitis caused by specific
pathogens or groups of pathogens (contagious, environmental, major, minor, or
any) were used to estimate risk ratios and 95% confidence intervals. Data
preparation and parameter estimation were performed using the open source
statistical analysis software R. We observed no effect of any variable
describing teat condition on the risk of new intramammary infections,
inflammatory responses, or mastitis. Intramammary infections of the same udder
quarter in the preceding month did not affect risk either
A root-cause analysis of maternal deaths in Botswana: towards developing a culture of patient safety and quality improvement
BACKGROUND: In 2007, 95% of women in Botswana delivered in health facilities with 73% attending at least 4 antenatal care visits. HIV-prevalence in pregnant women was 28.7%. The maternal mortality ratio in 2010 was 163 deaths per 100 000 live births versus the government target of 130 for that year, indicating that the Millennium Development Goal 5 was unlikely to be met. A root-cause analysis was carried out with the aim of determining the underlying causes of maternal deaths reported in 2010, to categorise contributory factors and to prioritise appropriate interventions based on the identified causes, to prevent further deaths. METHODS: Case-notes for maternal deaths were reviewed by a panel of five clinicians, initially independently then discussed together to achieve consensus on assigning contributory factors, cause of death and whether each death was avoidable or not at presentation to hospital. Factors contributing to maternal deaths were categorised into organisational/management, personnel, technology/equipment/supplies, environment and barriers to accessing healthcare. RESULTS: Fifty-six case notes were available for review from 82 deaths notified in 2010, with 0–4 contributory factors in 19 deaths, 5–9 in 27deaths and 9–14 in nine. The cause of death in one case was not ascertainable since the notes were incomplete. The high number of contributory factors demonstrates poor quality of care even where deaths were not avoidable: 14/23 (61%) of direct deaths were considered avoidable compared to 12/32 (38%) indirect deaths. Highest ranking categories were: failure to recognise seriousness of patients’ condition (71% of cases); lack of knowledge (67%); failure to follow recommended practice (53%); lack of or failure to implement policies, protocols and guidelines (44%); and poor organisational arrangements (35%). Half the deaths had some barrier to accessing health services. CONCLUSIONS: Root-cause analysis demonstrates the interactions between patients, health professionals and health system in generating adverse outcomes for patients. The lessons provided indicate where training of undergraduate and postgraduate medical, midwifery and nursing students need to be intensified, with emphasis on evidence-based practice and adherence to protocols. Action plans and interventions aimed at changing the circumstances that led to maternal deaths can be implemented and re-evaluated
Neonatal-onset multisystem inflammatory disease responsive to interleukin-1 beta inhibition
BACKGROUND:Neonatal-onset multisystem inflammatory disease is characterized by fever, urticarial rash, aseptic meningitis, deforming arthropathy, hearing loss, and mental retardation. Many patients have mutations in the cold-induced autoinflammatory syndrome 1 (CIAS1) gene, encoding cryopyrin, a protein that regulates inflammation.METHODS:We selected 18 patients with neonatal-onset multisystem inflammatory disease (12 with identifiable CIAS1 mutations) to receive anakinra, an interleukin-1-receptor antagonist (1 to 2 mg per kilogram of body weight per day subcutaneously). In 11 patients, anakinra was withdrawn at three months until a flare occurred. The primary end points included changes in scores in a daily diary of symptoms, serum levels of amyloid A and C-reactive protein, and the erythrocyte sedimentation rate from baseline to month 3 and from month 3 until a disease flare.RESULTS:All 18 patients had a rapid response to anakinra, with disappearance of rash. Diary scores improved (P<0.001) and serum amyloid A (from a median of 174 mg to 8 mg per liter), C-reactive protein (from a median of 5.29 mg to 0.34 mg per deciliter), and the erythrocyte sedimentation rate decreased at month 3 (all P<0.001), and remained low at month 6. Magnetic resonance imaging showed improvement in cochlear and leptomeningeal lesions as compared with baseline. Withdrawal of anakinra uniformly resulted in relapse within days; retreatment led to rapid improvement. There were no drug-related serious adverse events.CONCLUSIONS:Daily injections of anakinra markedly improved clinical and laboratory manifestations in patients with neonatal-onset multisystem inflammatory disease, with or without CIAS1 mutations
Advances for Treating in-Hospital Cardiac Arrest: Safety and Effectiveness of a New Automatic External Cardioverter-Defibrillator
OBJECTIVES:
The purpose of this study was to prospectively analyze the performance and safety of a new programmable, fully automatic external cardioverter-defibrillator (AECD) in a European multicenter trial. BACKGROUND Although, the response time to cardiac arrest (CA) is a major determinant of mortality and morbidity, in-hospital strategies have not significantly changed during the last 30 years.
METHODS:
Patients (n = 117) at risk of CA in monitored wards (n = 51) and patients undergoing electrophysiologic testing or implantable cardioverter-defibrillator (ICD) implantation (n = 66) were enrolled. The accuracy of the automatic response of the device to any change of rhythm (lasting >1 s and >4 beats) was confirmed by reviewing the simultaneously recorded Holter data and the programmed parameters.
RESULTS:
During 1,240 h, 1,988 episodes of rhythm changes were documented. A total of 115 episodes lasted > or =10 s or needed treatment (pacing, n = 32; ICD, n = 51; AECD, n = 35) for termination. The device detected ventricular tachyarrhythmias with a sensitivity of 100% and specificity of 97.6% (true negatives, n = 1,454; true positives, n = 499; false positives, n = 35; false negatives, n = 0). The false positives were all caused by T-wave oversensing during ventricular pacing. There were no complications or adverse events. The mean response time was 14.4 s for those episodes needing a full charge of the capacitor.
CONCLUSIONS:
This new AECD is safe and effective in detecting, monitoring, and treating spontaneous arrhythmias. This fully automatic device shortens the response time to treatment, and it is likely that it will significantly improve the outcome of patients with in-hospital CA
Dynamics of Wetting Fronts in Porous Media
We propose a new phenomenological approach for describing the dynamics of
wetting front propagation in porous media. Unlike traditional models, the
proposed approach is based on dynamic nature of the relation between capillary
pressure and medium saturation. We choose a modified phase-field model of
solidification as a particular case of such dynamic relation. We show that in
the traveling wave regime the results obtained from our approach reproduce
those derived from the standard model of flow in porous media. In more general
case, the proposed approach reveals the dependence of front dynamics upon the
flow regime.Comment: 4 pages, 2 figures, revte
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