4,249 research outputs found
Current treatments to counter sleep dysfunction as a pathogenic stimulus of fibromyalgia
Fibromyalgia is characterized by chronic widespread pain, fatigue and nonrestorative sleep. Polysomnography showed reduced short-wave sleep and abnormal alpha rhythms during nonrapid eye movement sleep in patients with fibromyalgia. However, sleep dysfunction might be pathogenic in fibromyalgia since myalgia and fatigue could be induced in healthy individuals by disrupting sleep. Poor sleep quality was a major risk factor for the subsequent development of chronic widespread pain in healthy pain-free individuals. Sleep disruption leads to impairment of the descending pain inhibition pathways. Aside from good sleep, hygiene, exercise can promote sleep. Among currently available pharmacological treatments, evidence suggests amitriptyline and pregabalin can improve sleep in fibromyalgia
Exploring the Way to Approach the Efficiency Limit of Perovskite Solar Cells by Drift-Diffusion Model
Drift-diffusion model is an indispensable modeling tool to understand the
carrier dynamics (transport, recombination, and collection) and simulate
practical-efficiency of solar cells (SCs) through taking into account various
carrier recombination losses existing in multilayered device structures.
Exploring the way to predict and approach the SC efficiency limit by using the
drift-diffusion model will enable us to gain more physical insights and design
guidelines for emerging photovoltaics, particularly perovskite solar cells. Our
work finds out that two procedures are the prerequisites for predicting and
approaching the SC efficiency limit. Firstly, the intrinsic radiative
recombination needs to be corrected after adopting optical designs which will
significantly affect the open-circuit voltage at its Shockley-Queisser limit.
Through considering a detailed balance between emission and absorption of
semiconductor materials at the thermal equilibrium, and the Boltzmann
statistics at the non-equilibrium, we offer a different approach to derive the
accurate expression of intrinsic radiative recombination with the optical
corrections for semiconductor materials. The new expression captures light
trapping of the absorbed photons and angular restriction of the emitted photons
simultaneously, which are ignored in the traditional Roosbroeck-Shockley
expression. Secondly, the contact characteristics of the electrodes need to be
carefully engineered to eliminate the charge accumulation and surface
recombination at the electrodes. The selective contact or blocking layer
incorporated nonselective contact that inhibits the surface recombination at
the electrode is another important prerequisite. With the two procedures, the
accurate prediction of efficiency limit and precise evaluation of efficiency
degradation for perovskite solar cells are attainable by the drift-diffusion
model.Comment: 32 pages, 11 figure
Capacitors can radiate - some consequences of the two-capacitor problem with radiation
We fill a gap in the arguments of Boykin et al [American Journal of Physics,
Vol 70 No. 4, pp 415-420 (2002)] by not invoking an electric current loop (i.e.
magnetic dipole model) to account for the radiation energy loss, since an
obvious corollary of their results is that the capacitors should radiate
directly even if the connecting wires are shrunk to zero length. That this is
so is shown here by a direct derivation of capacitor radiation using an
oscillating electric dipole radiator model for the capacitors as well as the
alternative less widely known magnetic 'charge' current loop representation for
an electric dipole [see for example "Electromagnetic Waves" by S.A.Schlekunoff,
van Nostrand (1948)]. Implications for Electromagnetic Compliance (EMC) issues
as well as novel antenna designs further motivate the purpose of this paper.Comment: 5 Pages with No figure
Small Circle, Entrenched Interest: The Electoral Anomalies of Hong Kong Deputies to the National People's Congress
Theoretically, Hong Kong deputies to the National People's Congress (NPC) represent the interests of Hong Kong people in China's highest organ of state power. The Central Authorities, through the Standing Committee of the NPC, exert a tight control over the electoral process in Hong Kong by making electoral rules, limiting the scope of eligible voters, and by utilising other formal and informal control mechanisms. Yet, a degree of autonomy in the electoral process produces results different from those expected by the Central Authorities. This article argues that the “small circle” election creates opportunities and incentives for developing special interests. Gradually, these special interests become entrenched and develop a life of their own.published_or_final_versio
Fatigue in rheumatoid arthritis
This is an editorial and does not contain an abstract
From the surface to the seafloor: How giant larvaceans transport microplastics into the deep sea.
Plastic waste is a pervasive feature of marine environments, yet little is empirically known about the biological and physical processes that transport plastics through marine ecosystems. To address this need, we conducted in situ feeding studies of microplastic particles (10 to 600 μm in diameter) with the giant larvacean Bathochordaeus stygius. Larvaceans are abundant components of global zooplankton assemblages, regularly build mucus "houses" to filter particulate matter from the surrounding water, and later abandon these structures when clogged. By conducting in situ feeding experiments with remotely operated vehicles, we show that giant larvaceans are able to filter a range of microplastic particles from the water column, ingest, and then package microplastics into their fecal pellets. Microplastics also readily affix to their houses, which have been shown to sink quickly to the seafloor and deliver pulses of carbon to benthic ecosystems. Thus, giant larvaceans can contribute to the vertical flux of microplastics through the rapid sinking of fecal pellets and discarded houses. Larvaceans, and potentially other abundant pelagic filter feeders, may thus comprise a novel biological transport mechanism delivering microplastics from surface waters, through the water column, and to the seafloor. Our findings necessitate the development of tools and sampling methodologies to quantify concentrations and identify environmental microplastics throughout the water column
Characterization, Modeling and Analysis of Organic Light-Emitting Diodes With Different Structures
This paper demonstrates that organic light-emitting diodes (OLED) of different structures can characterized and modeled using a combination of the photo-electro-thermal (PET) theory and spectral power distribution modeling. The photometric, electrical, thermal and chromatic properties of OLED devices are incorporated into a model framework so that the performance of OLED of different structures can be compared. A concept of luminance uniformity over the OLED surfaces is also introduced for comparing OLED with large surface areas. Experimental results are included to verify the OLED models and compare the characteristics of two different OLED samples. Based on the same PET framework, some differences of OLEDs and inorganic LEDs are addressed and discussed.published_or_final_versio
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