Photoelectrochemical solar water splitting has become a potential approach for producing clean hydrogen fuels by utilizing semiconductor photoelectrodes and solar energy. Among emerging metal oxide ...photoelectrodes, iron vanadate (FeVO4) with its unique electronic band structure and suitable bandgap energies for absorbing visible light from the solar spectrum has become a promising photoanode. However, the reported photocurrent density of this material is still low because of the poor water oxidation kinetics and the slow separation of carriers, leading to recombination at the surface. In this study, we attempted to solve these limitations by nanostructuring the FeVO4 photoanode and modifying its surface with cocatalysts (CoO x , CoPi, and CoO x –CoPi). Both photocurrent and onset potential are significantly improved, resulting from the enhancement of charge injection and separation efficiencies. For the first time, the dual layer of oxygen evolution CoO x –CoPi catalysts is found more effective than single-layer CoO x or CoPi catalysts for the nanoporous FeVO4 photoanode with the increased photocurrent density at 1.23 V vs RHE of a 5-fold improvement compared to the pristine FeVO4. This result offers a strategy to further improve FeVO4 photoanode performance for efficient solar water splitting toward practical applications.
Abstract
We combine our dynamical modeling black-hole mass measurements from the Lick AGN Monitoring Project 2016 sample with measured cross-correlation time lags and line widths to recover ...individual scale factors,
f
, used in traditional reverberation-mapping analyses. We extend our sample by including prior results from Code for AGN Reverberation and Modeling of Emission Lines (
caramel
) studies that have utilized our methods. Aiming to improve the precision of black-hole mass estimates, as well as uncover any regularities in the behavior of the broad-line region (BLR), we search for correlations between
f
and other AGN/BLR parameters. We find (i) evidence for a correlation between the virial coefficient
log
10
(
f
mean
,
σ
)
and black-hole mass, (ii) marginal evidence for a similar correlation between
log
10
(
f
rms
,
σ
)
and black-hole mass, (iii) marginal evidence for an anticorrelation of BLR disk thickness with
log
10
(
f
mean
,
FWHM
)
and
log
10
(
f
rms
,
FWHM
)
, and (iv) marginal evidence for an anticorrelation of inclination angle with
log
10
(
f
mean
,
FWHM
)
,
log
10
(
f
rms
,
σ
)
, and
log
10
(
f
mean
,
σ
)
. Last, we find marginal evidence for a correlation between line-profile shape, when using the root-mean-square spectrum,
log
10
(
FWHM
/
σ
)
rms
, and the virial coefficient,
log
10
(
f
rms
,
σ
)
, and investigate how BLR properties might be related to line-profile shape using
caramel
models.
Tailoring the size and surface chemistry of nanoparticles allows one to control their position in a block copolymer, but this is usually limited to one‐dimensional distribution across domains. Here, ...the hierarchical assembly of poly(ethylene oxide)‐stabilized gold nanoparticles (Au‐PEO) into hexagonally packed clusters inside mesostructured ultrathin films of polystyrene‐block‐poly(methyl methacrylate) (PS‐b‐PMMA) is described. A close examination of the structural evolution at different nanoparticle filling fractions and PEO ligand molecular weights suggests that the mechanism leading to this structure‐within‐structure is the existence of two phase separation processes operating on different time scales. The length of the PEO ligand is shown to influence not only the interparticle distances but also the phase separation processes. These conclusions are supported by novel mesoscopic simulations, which provide additional insight into the kinetic and thermodynamic factors that are responsible for this behavior.
Combining block copolymers with nanoparticles that are highly incompatible with one block and only slightly incompatible with the other leads to hierarchical nanoparticle structures. While the block copolymer domains evolve, the nanoparticles segregate to the least incompatible domain. Then, they phase separate from it, forming hexagonally packed arrays within its confines, where interparticle distance is determined by the ligand length.
Symptomatic chronic low back and leg pain resulting from lumbar spinal stenosis is expensive to treat and manage. A randomized, controlled, multicenter US Food and Drug Administration Investigational ...Device Exemption clinical trial assessed treatment-related patient outcomes comparing the Coflex® Interlaminar Stabilization Device, an interlaminar stabilization implant inserted following decompressive surgical laminotomy in the lumbar spine, to instrumented posterolateral fusion among patients with moderate to severe spinal stenosis. This study uses patient-reported outcomes and clinical events from the trial along with costs and expected resource utilization to determine cost effectiveness.
A decision-analytic model compared outcomes over 5 years. Clinical input parameters were derived from the trial. Oswestry Disability Index scores were converted to utilities. Treatment patterns over 5 years were estimated based on claims analyses and expert opinion. A third-party payer perspective was used; costs (in $US 2013) and outcomes were discounted at 3% annually. Sensitivity analyses examined the influence of key parameters. Analyses were conducted using Medicare payment rates and typical commercial reimbursements.
Five-year costs were lower for patients implanted with Coflex compared to those undergoing fusion. Average Medicare payments over 5 years were estimated at $15,182 for Coflex compared to $26,863 for the fusion control, a difference of $11,681. Mean quality-adjusted life years were higher for Coflex patients compared to controls (3.02 vs 2.97). Results indicate that patients implanted with the Coflex device derive more utility, on average, than those treated with fusion, but at substantially lower costs. The cost advantage was greater when evaluating commercial insurance payments. Subgroup analyses found that the cost advantage for Coflex relative to fusion was even larger for two-level procedures compared to one-level procedures.
The Coflex Interlaminar Stabilization Device was found to be cost effective compared to instrumented posterolateral fusion for treatment of lumbar spinal stenosis. It provided higher utility at substantially lower cost.
Recent articles in the lay press and literature have raised concerns about the ability to report honest adverse event data from industry-sponsored spine surgery studies. To address this, clinical ...trials may utilize an independent Clinical Events Committee (CEC) to review adverse events and readjudicate the severity and relatedness accordingly. We are aware of no prior study that has quantified either the degree to which investigator bias is present in adverse event reporting or the effect that an independent CEC has on mitigating this potential bias.
The coflex Investigational Device Exemption study is a prospective randomized controlled trial comparing coflex (Paradigm Spine) stabilization with lumbar spinal fusion to treat spinal stenosis and spondylolisthesis. Investigators classified the severity of adverse events (mild, moderate, or severe) and their relationship to the surgery and device (unrelated, unlikely, possibly, probably, or definitely). An independent CEC, composed of three spine surgeons without affiliation to the study sponsor, reviewed and reclassified all adverse event reports submitted by the investigators.
The CEC reclassified the level of severity, relation to the surgery, and/or relation to the device in 394 (37.3%) of 1055 reported adverse events. The proportion of adverse events that underwent reclassification was similar in the coflex and fusion groups (37.9% compared with 36.0%, p = 0.56). The CEC was 5.3 (95% confidence interval CI, 2.6 to 10.7) times more likely to upgrade than downgrade the adverse event. The CEC was 7.3 (95% CI, 5.1 to 10.6) times more likely to upgrade than downgrade the relationship to the surgery and 11.6 (95% CI, 7.5 to 18.8) times more likely to upgrade than downgrade the relationship to the device. The status of the investigator's financial interest in the company had little effect on the reclassification of adverse events.
Thirty-seven percent of adverse events were reclassified by the CEC; the large majority of the reclassifications were an upgrade in the level of severity or a designation of greater relatedness to the surgery or device.
An independent CEC can identify and mitigate potential inherent investigator bias and facilitate an accurate assessment of the safety profile of an investigational device, and a CEC should be considered a requisite component of future clinical trials.
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