588 research outputs found
Dietary Liberalization in Tetrahydrobiopterin-Treated PKU Patients:Does It Improve Outcomes?
Purpose: this systematic review aimed to assess the effects of dietary liberalization following tetrahydrobiopterin (BH4) treatment on anthropometric measurements, nutritional biomarkers, quality of life, bone density, mental health and psychosocial functioning, and burden of care in PKU patients. Methods: the PubMed, Cochrane, and Embase databases were searched on 7 April 2022. We included studies that reported on the aforementioned domains before and after dietary liberalization as a result of BH4 treatment in PKU patients. Exclusion criteria were: studies written in a language other than English; studies that only included data of a BH4 loading test; insufficient data for the parameters of interest; and wrong publication type. Both within-subject and between-subject analyses were assessed, and meta-analyses were performed if possible. Results: twelve studies containing 14 cohorts and 228 patients were included. Single studies reported few significant differences. Two out of fifteen primary meta-analyses were significant; BMI was higher in BH4-treated patients versus controls (p = 0.02; standardized mean difference (SMD) (95% confidence interval (CI)) = −0.37 (−0.67, −0.06)), and blood cholesterol concentrations increased after starting BH4 treatment (p = 0.01; SMD (CI) = −0.70 (−1.26, −0.15)). Conclusion: there is no clear evidence that dietary liberalization after BH4 treatment has a positive effect on anthropometric measurements, nutritional biomarkers, or quality of life. No studies could be included for bone density, mental health and psychosocial functioning, and burden of care
Rectification and Flux Reversals for Vortices Interacting with Triangular Traps
We simulate vortices in superconductors interacting with two-dimensional
arrays of triangular traps. We find that, upon application of an ac drive, a
net dc flow can occur which shows current reversals with increasing ac drive
amplitude for certain vortex densities, in agreement with recent experiments
and theoretical predictions. We identify the vortex dynamics responsible for
the different rectification regimes. We also predict the occurrence of a novel
transverse rectification effect in which a dc flow appears that is transverse
to the direction of the applied ac drive.Comment: 4 pages, 4 postscript figure
Spin Excitations in La2CuO4: Consistent Description by Inclusion of Ring-Exchange
We consider the square lattice Heisenberg antiferromagnet with plaquette ring
exchange and a finite interlayer coupling leading to a consistent description
of the spin-wave excitation spectrum in La2CuO4. The values of the in-plane
exchange parameters, including ring-exchange J_{\Box}, are obtained
consistently by an accurate fit to the experimentally observed in-plane
spin-wave dispersion, while the out-of-plane exchange interaction is found from
the temperature dependence of the sublattice magnetization at low temperatures.
The fitted exchange interactions J=151.9 meV and J_{\Box}=0.24 J give values
for the spin stiffness and the Neel temperature in excellent agreement with the
experimental data.Comment: 4 pages, 1 figure, RevTe
Bioprospecting the thermal waters of the Roman Baths:Isolation of oleaginous species and analysis of the FAME profile for biodiesel production
The extensive diversity of microalgae provides an opportunity to undertake bioprospecting for species possessing features suited to commercial scale cultivation. The outdoor cultivation of microalgae is subject to extreme temperature fluctuations; temperature tolerant microalgae would help mitigate this problem. The waters of the Roman Baths, which have a temperature range between 39°C and 46°C, were sampled for microalgae. A total of 3 green algae, 1 diatom and 4 cyanobacterial species were successfully isolated into ‘unialgal’ culture. Four isolates were filamentous, which could prove advantageous for low energy dewatering of cultures using filtration. Lipid content, profiles and growth rates of the isolates were examined at temperatures of 20, 30, 40°C, with and without nitrogen starvation and compared against the oil producing green algal species, Chlorella emersonii. Some isolates synthesized high levels of lipids, however, all were most productive at temperatures lower than those of the Roman Baths. The eukaryotic algae accumulated a range of saturated and polyunsaturated FAMEs and all isolates generally showed higher lipid accumulation under nitrogen deficient conditions (Klebsormidium sp. increasing from 1.9% to 16.0% and Hantzschia sp. from 31.9 to 40.5%). The cyanobacteria typically accumulated a narrower range of FAMEs that were mostly saturated, but were capable of accumulating a larger quantity of lipid as a proportion of dry weight (M. laminosus, 37.8% fully saturated FAMEs). The maximum productivity of all the isolates was not determined in the current work and will require further effort to optimise key variables such as light intensity and media composition
Carbon nanotubes in TiO<sub>2</sub> nanofiber photoelectrodes for high-performance perovskite solar cells
1D semiconducting oxides are unique structures that have been widely used for photovoltaic (PV) devices due to their capability to provide a direct pathway for charge transport. In addition, carbon nanotubes (CNTs) have played multifunctional roles in a range of PV cells because of their fascinating properties. Herein, the influence of CNTs on the PV performance of 1D titanium dioxide nanofiber (TiO2 NF) photoelectrode perovskite solar cells (PSCs) is systematically explored. Among the different types of CNTs, single-walled CNTs (SWCNTs) incorporated in the TiO2 NF photoelectrode PSCs show a significant enhancement (≈40%) in the power conversion efficiency (PCE) as compared to control cells. SWCNTs incorporated in TiO2 NFs provide a fast electron transfer within the photoelectrode, resulting in an increase in the short-circuit current (J sc) value. On the basis of our theoretical calculations, the improved open-circuit voltage (V oc) of the cells can be attributed to a shift in energy level of the photoelectrodes after the introduction of SWCNTs. Furthermore, it is found that the incorporation of SWCNTs into TiO2 NFs reduces the hysteresis effect and improves the stability of the PSC devices. In this study, the best performing PSC device constructed with SWCNT structures achieves a PCE of 14.03%
Mixed States of Composite Fermions Carrying Two and Four Vortices
There now exists preliminary experimental evidence for some fractions, such
as = 4/11 and 5/13, that do not belong to any of the sequences
, and being integers. We propose that these states
are mixed states of composite fermions of different flavors, for example,
composite fermions carrying two and four vortices. We also obtain an estimate
of the lowest-excitation dispersion curve as well as the transport gap; the
gaps for 4/11 are smaller than those for 1/3 by approximately a factor of 50.Comment: Accepted for PRB rapid communication (scheduled to appear in Nov 15,
2000 issue
Recapitulation of the EEF1A2 D252H neurodevelopmental disorder-causing missense mutation in mice reveals a toxic gain of function
Recurrent plasmodium falciparum malaria infections in kenyan children diminish t-cell immunity to epstein barr virus lytic but not latent antigens
Plasmodium falciparum malaria (Pf-malaria) and Epstein Barr Virus (EBV) infections coexist in children at risk for endemic Burkitt's lymphoma (eBL); yet studies have only glimpsed the cumulative effect of Pf-malaria on EBV-specific immunity. Using pooled EBV lytic and latent CD8+ T-cell epitope-peptides, IFN-γ ELISPOT responses were surveyed three times among children (10 months to 15 years) in Kenya from 2002–2004. Prevalence ratios (PR) and 95% confidence intervals (CI) were estimated in association with Pf-malaria exposure, defined at the district-level (Kisumu: holoendemic; Nandi: hypoendemic) and the individual-level. We observed a 46% decrease in positive EBV lytic antigen IFN-γ responses among 5–9 year olds residing in Kisumu compared to Nandi (PR: 0.54; 95% CI: 0.30–0.99). Individual-level analysis in Kisumu revealed further impairment of EBV lytic antigen responses among 5–9 year olds consistently infected with Pf-malaria compared to those never infected. There were no observed district- or individual-level differences between Pf-malaria exposure and EBV latent antigen IFN-γ response. The gradual decrease of EBV lytic antigen but not latent antigen IFN-γ responses after primary infection suggests a specific loss in immunological control over the lytic cycle in children residing in malaria holoendemic areas, further refining our understanding of eBL etiology
Segregated tunneling-percolation model for transport nonuniversality
We propose a theory of the origin of transport nonuniversality in disordered
insulating-conducting compounds based on the interplay between microstructure
and tunneling processes between metallic grains dispersed in the insulating
host. We show that if the metallic phase is arranged in quasi-one dimensional
chains of conducting grains, then the distribution function of the chain
conductivities g has a power-law divergence for g -> 0 leading to nonuniversal
values of the transport critical exponent t. We evaluate the critical exponent
t by Monte Carlo calculations on a cubic lattice and show that our model can
describe universal as well nonuniversal behavior of transport depending on the
value of few microstructural parameters. Such segregated tunneling-percolation
model can describe the microstructure of a quite vast class of materials known
as thick-film resistors which display universal or nonuniversal values of t
depending on the composition.Comment: 8 pages, 5 figures (Phys. Rev. B - 1 August 2003)(fig1 replaced
Internet-Based Interactive Package for Diagnostic Assessment on Learning of Fluid Mechanics
- …