586 research outputs found
Efficient Water-Splitting Device Based on a Bismuth Vanadate Photoanode and Thin-Film Silicon Solar Cells
A hybrid photovoltaic/photoelectrochemical (PV/PEC) water-splitting device with a benchmark solar-to-hydrogen conversion efficiency of 5.2â% under simulated air mass (AM) 1.5 illumination is reported. This cell consists of a gradient-doped tungstenâbismuth vanadate (W:BiVO_4) photoanode and a thin-film silicon solar cell. The improvement with respect to an earlier cell that also used gradient-doped W:BiVO4 has been achieved by simultaneously introducing a textured substrate to enhance light trapping in the BiVO4 photoanode and further optimization of the W gradient doping profile in the photoanode. Various PV cells have been studied in combination with this BiVO_4 photoanode, such as an amorphous silicon (a-Si:H) single junction, an a-Si:H/a-Si:H double junction, and an a-Si:H/nanocrystalline silicon (nc-Si:H) micromorph junction. The highest conversion efficiency, which is also the record efficiency for metal oxide based water-splitting devices, is reached for a tandem system consisting of the optimized W:BiVO_4 photoanode and the micromorph (a-Si:H/nc-Si:H) cell. This record efficiency is attributed to the increased performance of the BiVO_4 photoanode, which is the limiting factor in this hybrid PEC/PV device, as well as better spectral matching between BiVO_4 and the nc-Si:H cell
Risk of Cognitive Impairment in Patients With Parkinsonâs Disease With Visual Hallucinations and Subjective Cognitive Complaints
Cognitive impairment; Parkinson's disease; Visual hallucinationsDeterioro cognitivo; Enfermedad de Parkinson; Alucinaciones visualesDeteriorament cognitiu; Malaltia de Parkinson; Al·lucinacions visualsBackground and Purpose
Visual hallucinations (VH) and subjective cognitive complaints (SCC) are associated with cognitive impairment (CI) in Parkinsonâs disease. Our aims were to determine the association between VH and SCC and the risk of CI development in a cohort of patients with Parkinsonâs disease and normal cognition (PD-NC).
Methods
Patients with PD-NC (total score of >80 on the Parkinsonâs Disease Cognitive Rating Scale [PD-CRS]) recruited from the Spanish COPPADIS cohort from January 2016 to November 2017 were followed up after 2 years. Subjects with a score of â„1 on domain 5 and item 13 of the Non-Motor Symptoms Scale at baseline (V0) were considered as âwith SCCâ and âwith VH,â respectively. CI at the 2-year follow-up (plus or minus 1 month) (V2) was defined as a PD-CRS total score of <81.
Results
At V0 (n=376, 58.2% males, age 61.14±8.73 years [mean±SD]), the frequencies of VH and SCC were 13.6% and 62.2%, respectively. VH were more frequent in patients with SCC than in those without: 18.8% (44/234) vs 4.9% (7/142), p<0.0001. At V2, 15.2% (57/376) of the patients had developed CI. VH presenting at V0 was associated with a higher risk of CI at V2 (odds ratio [OR]=2.68, 95% confidence interval=1.05â6.83, p=0.0.039) after controlling for the effects of age, disease duration, education, medication, motor and nonmotor status, mood, and PD-CRS total score at V0. Although SCC were not associated with CI at V2, presenting both VH and SCC at V0 increased the probability of having CI at V2 (OR=3.71, 95% confidence interval=1.36â10.17, p=0.011).
Conclusions
VH were associated with the development of SCC and CI at the 2-year follow-up in patients with PD-NC.The resources obtained for the development of this project have been obtained by the Degen Foundation (https://fundaciondegen.org/). A part of the Project is financed with grants from the Spanish Ministry of Economy and Competitiveness [PI16/01575] co-founded by ISCIII (ConcesiĂłn de subvenciones de Proyectos de InvestigaciĂłn en Salud de la convocatoria 2020 de la AcciĂłn EstratĂ©gica en Salud 2017-2020 por el proyecto âPROGRESIĂN NO MOTORA E IMPACTO EN LA CALIDAD DE VIDA EN LA ENFERMEDAD DE PARKINSONâ)
Three-loop \beta-functions for top-Yukawa and the Higgs self-interaction in the Standard Model
We analytically compute the dominant contributions to the \beta-functions for
the top-Yukawa coupling, the strong coupling and the Higgs self-coupling as
well as the anomalous dimensions of the scalar, gluon and quark fields in the
unbroken phase of the Standard Model at three-loop level. These are mainly the
QCD and top-Yukawa corrections. The contributions from the Higgs
self-interaction which are negligible for the running of the top-Yukawa and the
strong coupling but important for the running of the Higgs self-coupling are
also evaluated.Comment: 22 pages, 7 figures. Few extra citations are added; the plots are
improved. Results in computer readable form can be retrieved from
http://www-ttp.particle.uni-karlsruhe.de/Progdata/ttp12/ttp12-012
The NANOG transcription factor induces type 2 deiodinase expression and regulates the intracellular activation of thyroid hormone in keratinocyte carcinomas
Type 2 deiodinase (D2), the principal activator of thyroid hormone (TH) signaling in target tissues, is expressed in cutaneous squamous cell carcinomas (SCCs) during late tumorigenesis, and its repression attenuates the invasiveness and metastatic spread of SCC. Although D2 plays multiple roles in cancer progression, nothing is known about the mechanisms regulating D2 in cancer. To address this issue, we investigated putative upstream regulators of D2 in keratinocyte carcinomas. We found that the expression of D2 in SCC cells is positively regulated by the NANOG transcription factor, whose expression, besides being causally linked to embryonic stemness, is associated with many human cancers. We also found that NANOG binds to the D2 promoter and enhances D2 transcription. Notably, blockage of D2 activity reduced NANOG-induced cell migration as well as the expression of key genes involved in epithelialâmesenchymal transition in SCC cells. In conclusion, our study reveals a link among endogenous endocrine regulators of cancer, thyroid hormone and its activating enzyme, and the NANOG regulator of cancer biology. These findings could provide the basis for the development of TH inhibitors as context-dependent anti-tumor agents
Higgs mass and vacuum stability in the Standard Model at NNLO
We present the first complete next-to-next-to-leading order analysis of the
Standard Model Higgs potential. We computed the two-loop QCD and Yukawa
corrections to the relation between the Higgs quartic coupling (lambda) and the
Higgs mass (Mh), reducing the theoretical uncertainty in the determination of
the critical value of Mh for vacuum stability to 1 GeV. While lambda at the
Planck scale is remarkably close to zero, absolute stability of the Higgs
potential is excluded at 98% C.L. for Mh < 126 GeV. Possible consequences of
the near vanishing of lambda at the Planck scale, including speculations about
the role of the Higgs field during inflation, are discussed.Comment: 35 pages, 8 figures. Final published version, misprints fixed,
figures update
The Astronomical Orientation of Ancient Greek Temples
Despite its appearing to be a simple question to answer, there has been no consensus as to whether or not the alignments of ancient Greek temples reflect astronomical intentions. Here I present the results of a survey of archaic and classical Greek temples in Sicily and compare them with temples in Greece. Using a binomial test I show strong evidence that there is a preference for solar orientations. I then speculate that differences in alignment patterns between Sicily and Greece reflect differing pressures in the expression of ethnic identity
Higgs Interference Effects in \Pg \Pg \to \PZ\PZ and their Uncertainty
Interference between the Standard Model Higgs boson and continuum
contributions is considered in the heavy-mass scenario. Results are available
at leading order for the background. It is discussed how to combine the result
with the next-to-next-to-leading order Higgs production cross-section and a
proposal for estimating the associated theoretical uncertainty is presented.Comment: 25 pages, 10 figures; improved numerical accuracy, Numerics updated,
conclusions unchanged, references added. v
Solar-driven CO2 reduction catalysed by hybrid supramolecular photocathodes and enhanced by ionic liquids
Photoelectrochemical carbon dioxide reduction (CO2) at ambient temperature and pressure was performed using molecular chromophores and catalyst assemblies on CuGaO2-based electrodes in an ionic liquid (IL) organic solution, acting as a CO2 absorbent and electrolyte. A simple and versatile methodology based on the silanization of the CuGaO2 electrode followed by electropolymerization provided a series of molecular and supramolecular hybrid photocathodes for solar driven CO2 reduction. Focusing on the cathodic half reactions, the most promising conditions for the formation of CO2 reduction products were determined. The results revealed a beneficial effect of the ionic liquid on the conversion of CO2 to formic acid and suppression of the production of hydrogen. The potentiality of anchoring supramolecular complexes on semiconductor photoelectrocatalysts was demonstrated to boost both carrier transport and catalytic activity with a FEred of up to 81% compared with the obtained FEred of 52% using bare CuGaO2 with formate as the major product
CD4 cell count and the risk of AIDS or death in HIV-Infected adults on combination antiretroviral therapy with a suppressed viral load: a longitudinal cohort study from COHERE.
BACKGROUND: Most adults infected with HIV achieve viral suppression within a year of starting combination antiretroviral therapy (cART). It is important to understand the risk of AIDS events or death for patients with a suppressed viral load.
METHODS AND FINDINGS: Using data from the Collaboration of Observational HIV Epidemiological Research Europe (2010 merger), we assessed the risk of a new AIDS-defining event or death in successfully treated patients. We accumulated episodes of viral suppression for each patient while on cART, each episode beginning with the second of two consecutive plasma viral load measurements 500 copies/”l, the first of two consecutive measurements between 50-500 copies/”l, cART interruption or administrative censoring. We used stratified multivariate Cox models to estimate the association between time updated CD4 cell count and a new AIDS event or death or death alone. 75,336 patients contributed 104,265 suppression episodes and were suppressed while on cART for a median 2.7 years. The mortality rate was 4.8 per 1,000 years of viral suppression. A higher CD4 cell count was always associated with a reduced risk of a new AIDS event or death; with a hazard ratio per 100 cells/”l (95% CI) of: 0.35 (0.30-0.40) for counts <200 cells/”l, 0.81 (0.71-0.92) for counts 200 to <350 cells/”l, 0.74 (0.66-0.83) for counts 350 to <500 cells/”l, and 0.96 (0.92-0.99) for counts â„500 cells/”l. A higher CD4 cell count became even more beneficial over time for patients with CD4 cell counts <200 cells/”l.
CONCLUSIONS: Despite the low mortality rate, the risk of a new AIDS event or death follows a CD4 cell count gradient in patients with viral suppression. A higher CD4 cell count was associated with the greatest benefit for patients with a CD4 cell count <200 cells/”l but still some slight benefit for those with a CD4 cell count â„500 cells/”l
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