78 research outputs found
The combined effects of contextual predictability and noise on the acoustic realisation of German syllables
Speakers tend to speak clearly in noisy environments, while they tend to reserve effort by shortening word duration in predictable contexts. It is unclear how these two communicative demands are met. The current study investigates the acoustic realizations of syllables in predictable vs unpredictable contexts across different background noise levels. Thirty-eight German native speakers produced 60 CV syllables in two predictability contexts in three noise conditions (reference = quiet, 0 dB and −10 dB signal-to-noise ratio). Duration, intensity (average and range), F0 (median), and vowel formants of the target syllables were analysed. The presence of noise yielded significantly longer duration, higher average intensity, larger intensity range, and higher F0. Noise levels affected intensity (average and range) and F0. Low predictability syllables exhibited longer duration and larger intensity range. However, no interaction was found between noise and predictability. This suggests that noise-related modifications might be independent of predictability-related changes, with implications for including channel-based and message-based formulations in speech production
Life-Threatening Laryngeal Edema and Hyponatremia during Hysteroscopy
We report on a 43-year-old patient undergoing a hysteroscopic myomectomy. After 80 minutes of operation, the patient developed laryngeal edema, requiring emergency tracheostomy. Hyponatremia (serum sodium 78 mmoL/L) indicated an irrigation fluid absorption. The patient developed shock, acute respiratory distress syndrome, acute renal failure, and diffuse intravascular coagulopathy. Resuscitation including continuous venovenous hemodiafiltration was required. Finally, the patient made a full clinical recovery.
Hysteroscopy usually has low risks. However, absorption of the irrigation fluid can result in life-threatening fluid overload and electrolyte disturbances. Accurate fluid balancing and limiting the operation time may prevent these complications
Improving the light-harvesting of amorphous silicon solar cells with photochemical upconversion
Single-threshold solar cells are fundamentally limited by their ability to
harvest only those photons above a certain energy. Harvesting below-threshold
photons and re-radiating this energy at a shorter wavelength would thus boost
the efficiency of such devices. We report an increase in light harvesting
efficiency of a hydrogenated amorphous silicon (a-Si:H) thin-film solar cell
due to a rear upconvertor based on sensitized triplet–triplet-annihilation in
organic molecules. Low energy light in the range 600–750 nm is converted to
550–600 nm light due to the incoherent photochemical process. A peak
efficiency enhancement of (1.0 ± 0.2)% at 720 nm is measured under irradiation
equivalent to (48 ± 3) suns (AM1.5). We discuss the pathways to be explored in
adapting photochemical UC for application in various single threshold devices
Improving the light-harvesting of second generation solar cells with photochemical upconversion
Photovoltaics (PV) offer a solution for the development of sustainable energy
sources, relying on the sheer abundance of sunlight: More sunlight falls on
the Earth’s surface in one hour than is required by its inhabitants in a year.
However, it is imperative to manage the wide distribution of photon energies
available in order to generate more cost efficient PV devices because single
threshold PV devices are fundamentally limited to a maximum conversion
efficiency, the Shockley-Queisser (SQ) limit. Recent progress has enabled the
production of c-Si cells with efficiencies as high as 25%,1 close to the
limiting efficiency of ∼30%. But these cells are rather expensive, and
ultimately the cost of energy is determined by the ratio of system cost and
efficiency of the PV device. A strategy to radically decrease this ratio is to
circumvent the SQ limit in cheaper, second generation PV devices. One
promising approach is the use of hydrogenated amorphous silicon (a-Si:H),
where film thicknesses on the order of several 100nm are sufficient.
Unfortunately, the optical threshold of a-Si:H is rather high (1.7-1.8 eV) and
the material suffers from light-induced degradation. Thinner absorber layers
in a-Si:H devices are generally more stable than thicker films due to the
better charge carrier extraction, but at the expense of reduced conversion
efficiencies, especially in the red part of the solar spectrum (absorption
losses). Hence for higher bandgap materials, which includes a-Si as well as
organic and dye-sensitized cells, the major loss mechanism is the inability to
harvest low energy photons
DNM1 encephalopathy: A new disease of vesicle fission.
ObjectiveTo evaluate the phenotypic spectrum caused by mutations in dynamin 1 (DNM1), encoding the presynaptic protein DNM1, and to investigate possible genotype-phenotype correlations and predicted functional consequences based on structural modeling.MethodsWe reviewed phenotypic data of 21 patients (7 previously published) with DNM1 mutations. We compared mutation data to known functional data and undertook biomolecular modeling to assess the effect of the mutations on protein function.ResultsWe identified 19 patients with de novo mutations in DNM1 and a sibling pair who had an inherited mutation from a mosaic parent. Seven patients (33.3%) carried the recurrent p.Arg237Trp mutation. A common phenotype emerged that included severe to profound intellectual disability and muscular hypotonia in all patients and an epilepsy characterized by infantile spasms in 16 of 21 patients, frequently evolving into Lennox-Gastaut syndrome. Two patients had profound global developmental delay without seizures. In addition, we describe a single patient with normal development before the onset of a catastrophic epilepsy, consistent with febrile infection-related epilepsy syndrome at 4 years. All mutations cluster within the GTPase or middle domains, and structural modeling and existing functional data suggest a dominant-negative effect on DMN1 function.ConclusionsThe phenotypic spectrum of DNM1-related encephalopathy is relatively homogeneous, in contrast to many other genetic epilepsies. Up to one-third of patients carry the recurrent p.Arg237Trp variant, which is now one of the most common recurrent variants in epileptic encephalopathies identified to date. Given the predicted dominant-negative mechanism of this mutation, this variant presents a prime target for therapeutic intervention
Effect of a back reflector
Photochemical upconversion is applied to a hydrogenated amorphous silicon
solar cell in the presence of a back-scattering layer. A custom-synthesized
porphyrin was utilized as the sensitizer species, with rubrene as the emitter.
Under a bias of 24 suns, a peak external quantum efficiency (EQE) enhancement
of ~2 % was observed at a wavelength of 720 nm. Without the scattering layer,
the EQE enhancement was half this value, indicating that the effect of the
back-scatterer is to double the efficacy of the upconverting device. The
results represent an upconversion figure of merit of 3.5 × 10–4 mA cm–2 sun–2,
which is the highest reported to date
Dynamics of disease characteristics and clinical management of critically ill COVID-19 patients over the time course of the pandemic: an analysis of the prospective, international, multicentre RISC-19-ICU registry.
BACKGROUND
It remains elusive how the characteristics, the course of disease, the clinical management and the outcomes of critically ill COVID-19 patients admitted to intensive care units (ICU) worldwide have changed over the course of the pandemic.
METHODS
Prospective, observational registry constituted by 90 ICUs across 22 countries worldwide including patients with a laboratory-confirmed, critical presentation of COVID-19 requiring advanced organ support. Hierarchical, generalized linear mixed-effect models accounting for hospital and country variability were employed to analyse the continuous evolution of the studied variables over the pandemic.
RESULTS
Four thousand forty-one patients were included from March 2020 to September 2021. Over this period, the age of the admitted patients (62 [95% CI 60-63] years vs 64 [62-66] years, p < 0.001) and the severity of organ dysfunction at ICU admission decreased (Sequential Organ Failure Assessment 8.2 [7.6-9.0] vs 5.8 [5.3-6.4], p < 0.001) and increased, while more female patients (26 [23-29]% vs 41 [35-48]%, p < 0.001) were admitted. The time span between symptom onset and hospitalization as well as ICU admission became longer later in the pandemic (6.7 [6.2-7.2| days vs 9.7 [8.9-10.5] days, p < 0.001). The PaO2/FiO2 at admission was lower (132 [123-141] mmHg vs 101 [91-113] mmHg, p < 0.001) but showed faster improvements over the initial 5 days of ICU stay in late 2021 compared to early 2020 (34 [20-48] mmHg vs 70 [41-100] mmHg, p = 0.05). The number of patients treated with steroids and tocilizumab increased, while the use of therapeutic anticoagulation presented an inverse U-shaped behaviour over the course of the pandemic. The proportion of patients treated with high-flow oxygen (5 [4-7]% vs 20 [14-29], p < 0.001) and non-invasive mechanical ventilation (14 [11-18]% vs 24 [17-33]%, p < 0.001) throughout the pandemic increased concomitant to a decrease in invasive mechanical ventilation (82 [76-86]% vs 74 [64-82]%, p < 0.001). The ICU mortality (23 [19-26]% vs 17 [12-25]%, p < 0.001) and length of stay (14 [13-16] days vs 11 [10-13] days, p < 0.001) decreased over 19 months of the pandemic.
CONCLUSION
Characteristics and disease course of critically ill COVID-19 patients have continuously evolved, concomitant to the clinical management, throughout the pandemic leading to a younger, less severely ill ICU population with distinctly different clinical, pulmonary and inflammatory presentations than at the onset of the pandemic
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