No abstract

Type Ia supernovae (SNe Ia) can be used as the standard candle to determine the cosmological distances because they are thought to have a uniform fuel amount. Recent observations of several overluminous SNe Ia suggest that the white dwarf masses at supernova explosion may significantly exceed the canonical Chandrasekhar mass limit. These massive white dwarfs may be supported by rapid differential rotation. Based on a singledegenerate model and the assumption that the white dwarf would differentially rotate when the accretion ratė M > 3 × 10 −7 M yr −1 , we have calculated the evolutions of close binaries consisting of a white dwarf and a normal companion. To include the effect of rotation, we introduce an effective mass M eff for white dwarfs. For the donor stars with two different metallicities Z = 0.02 and 0.001, we present the distribution of the initial donor star masses and the orbital periods of the progenitors of super-Chandrasekhar mass SNe Ia. The calculation results indicate that, for an initial massive white dwarf of 1.2 M , a considerable fraction of SNe Ia may result from superChandrasekhar mass white dwarfs, but very massive (> 1.7 M ) white dwarfs are difficult to form, and none of them could be found in old populations. However, super-Chandrasekhar mass SNe Ia are very rare when the initial mass of white dwarfs is 1.0 M . Additionally, SNe Ia in low metallicity environment are more likely to be homogeneous.

Gas temperature, electron density and electron temperature of a microwave excited microplasma are measured by optical emission spectroscopy. This microplasma is generated in the small gap of a microstrip split-ring resonator in argon at near atmospheric pressure. When less than 100 ppm of water is present in the plasma, the gas temperature can be obtained from the rotational temperature of the hydroxyl molecule (A 2Σ+, v = 0) and the electron density can be measured by the Stark broadening of the hydrogen Balmer β line. According to a collisional–radiative model, the electron temperature can be estimated from the measured excitation temperature of argon 4p and 5p levels. It is found that the values of these parameters (gas temperature, electron density and temperature) increase when the gap width of the resonator is reduced. However, when the microwave power increases, these parameters, especially the electron density, do not vary significantly. Discussions on this phenomenon, being very different from that in the low-pressure bounded discharges, are provided.

Summary Long-chain fatty acid oxidation disorders (LC-FAOD) are rare disorders characterized by acute crises of energy metabolism and severe energy deficiency that may present with cardiomyopathy, hypoglycemia, and/or rhabdomyolysis, which can lead to frequent hospitalizations and early death. An open-label Phase 2 study evaluated the efficacy of UX007, an investigational odd-carbon medium chain triglyceride, in 29 subjects with severe LC-FAOD. UX007 was administered over 78 weeks at a target dose of 25%–35% total daily caloric intake (mean 31%).The frequency and duration of major clinical events (hospitalizations, emergency room visits, and emergency home interventions due to rhabdomyolysis, hypoglycemia, and cardiomyopathy) occurring during 78 weeks of UX007 treatment was compared with the frequency and duration of events captured retrospectively from medical records for 78 weeks before UX007 initiation. The mean annualized event rates decreased from 1.69 to 0.88 events/year following UX007 initiation (p=0.021; 48.1% reduction). The mean annualized duration rate decreased from 5.96 to 2.96 days/year (p=0.028; 50.3% reduction). Hospitalizations due to rhabdomyolysis, the most common event, decreased from 1.03 to 0.63 events/year (p=0.104; 38.7% reduction). Initiation of UX007 eliminated hypoglycemia events leading to hospitalization (from 11 pre-UX007 hospitalizations, 0.30 events/year vs. 0; p=0.067) and ICU care (from 2 pre-UX007 ICU admissions, 0.05 events/year vs. 0; p=0.161) and reduced cardiomyopathy events (3 events vs. 1 event; 0.07 to 0.02 events/year, 69.7% decrease). The majority of treatment-related AEs were mild to moderate GI symptoms including diarrhea, vomiting, abdominal or gastrointestinal pain, which can be managed with smaller, frequent doses mixed with food.

The temporal evolution of electron density in a nanosecond pulsed argon microplasma is measured using a combination of Stark broadening and the optical emission line-ratio method. In the initial discharge period (0–100 ns), the electron density can reach as high as ∼1018 cm−3. It decreases to ∼1017–1016 cm−3 in the early afterglow period (100 ns–1 µs after the ignition) and ∼1016–1013 cm−3 in the late afterglow period (1–20 µs). It is demonstrated that the optical emission spectroscopy (OES) line-ratio method can obtain the electron density in the range 1013–1016 cm−3, while in the range 1016–1018 cm−3, the Stark broadening technique with argon 2p–1s lines (in Paschen's notation) is a better choice. These results are in good agreement with those from the Stark broadening technique with hydrogen Balmer lines. Finally, a possible mechanism for such a density evolution is briefly discussed.