To determine whether pars plana vitrectomy (PPV) with internal limiting membrane (ILM) peeling for rhegmatogenous retinal detachment (RRD) could get better functional and anatomical outcomes.
A ...comprehensive literature search was performed to find relevant studies. A meta-analysis was conducted by comparing the weighted mean differences (WMD) in the mean change of best corrected visual acuity (BCVA) from baseline and calculating the odd ratios (OR) for rates of epiretinal membrane (ERM) formation and recurrence of retinal detachment (RD).
Fourteen studies were selected, including 2259 eyes (825 eyes in the ILM peeling group and 1434 eyes in the non-ILM peeling group). There was no significant difference in terms of mean change in BCVA from baseline and the rate of RD recurrence (WMD = 0.02, 95% CI, -0.20 to 0.24, P = 0.86, and OR = 0.55, 95% CI, 0.24 to 1.26, P = 0.16), but ILM peeling was associated with a significantly lower frequency of postoperative ERM formation (OR = 0.13, 95% CI, 0.06 to 0.26, P<0.00001). Similar results were obtained in a sub-analysis based on macula-off RRD.
ILM peeling results in similar BCVA, with same rate of RD recurrence, but lower rate of postoperative ERM development. ILM peeling could be considered in selected cases with risk factors that are likely to develop an ERM.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
To compare the anatomical and visual outcomes of inverted internal limiting membrane (ILM) flap technique with the conventional ILM peeling for idiopathic large macular holes (MHs). A meta-analysis ...of randomized control trials (RCTs) using online databases including NCBI PubMed, ClinicalTrials.gov, and ISI Web of Science was performed. Anatomic success and type 1 closure rates, the mean postoperative best-corrected visual acuity (BCVA) and the mean change of BCVA from baseline were analyzed. Out of 251 articles, four described clinical trials matching the inclusion criteria and were selected. They included 276 eyes (135 eyes in the inverted ILM flap group and 141 eyes in the ILM peeling group). All the studies used gas tamponade, with two studies having a follow-up duration of 3 months, while one study had a follow-up of 6 months and one study- 12 months. The meta-analysis demonstrated that anatomic success and type 1 closure rates (presence of neurosensory retina in MH) were better in the inverted ILM flap technique (odds ratio (OR) = 4.89; 95% confidence interval (CI), 2.09-11.47; P = 0.0003 and OR = 5.23; 95% CI, 2.83-9.66; P<0.00001). Similarly, the inverted flap technique was superior in terms of postoperative logMAR BCVA and mean change of logMAR BCVA from baseline (weighted mean difference (WMD) = 0.17, 95% CI, 0.11 to 0.24, P<0.00001 and WMD = 0.08, 95% CI, 0.01 to 0.16, P = 0.03) Inverted ILM flap treatment resulted in better closure rates and visual acuity when compared to the standard ILM peeling for large MHs.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Amorphous carbon (a-C) films comprising different buffer layers were prepared by direct current magnetron sputtering on a 304 stainless steel (SS) substrate surface. Microstructures and performances ...of a-C films with buffer layers comprising Ti, Cr and W were investigated and evaluated as bipolar plate for proton exchange membrane fuel cell (PEMFC). All prepared a-C films are graphite-like carbon, and predeposition of the buffer layer promote the graphitization of the a-C film. The a-C film comprising a Cr buffer layer has highest percentage of sp2 hybridization contents, which directly improved the current conductivity with a resistivity of 2.73×10−6Ωm and an interfacial contact resistance of 16.65mΩcm2. Furthermore, dynamic polarization under a simulated PEMFC working environment shows that the corrosion resistance greatly improved. The corrosion current density of an a-C film with a Cr buffer layer stabilizes at a negative value after potentiostatic tests for 4h. The hydrophobic property is improved as well, which is beneficial to water management in PEMFC and for anticorrosion of the bipolar plate itself. Thus, the metal buffer layers make the a-C film more suitable for surface modification of a 304 SS bipolar plate, especially the a-C film with a Cr buffer layer.
•Predeposition of buffer layer promotes the graphitization of amorphous carbon film.•Amorphous carbon film with buffer layer shows lower resistivity and interfacial contact resistance.•The corrosion resistance is greatly improved after predeposition of buffer layer.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Excellent electrical conductivity and corrosion resistance make the graphite-like carbon film an ideal surface modification for metal bipolar plates, but the pinhole inside amorphous carbon (a-C) ...causes pitting corrosion of the substrate. Chromium interlayer amorphous carbon (Cr/a-C) was prepared for 304SS bipolar plate. The interlock structure between the Cr interlayer and a-C film prevented corrosive liquid from reaching the substrate. The Cr/a-C film was prepared on 304SS by direct current magnetron sputtering. The hydrophobic property, interfacial contact resistance (ICR), and corrosion resistance of Cr/a-C 304SS were investigated and compared with those of bare 304SS and a-C 304SS. In addition, the performance and stability of the assembled single fuel cell were analyzed. Results show that the contact angle with water of Cr/a-C 304SS is 89.5°. The ICR of Cr/a-C 304SS under compaction force of 150N/cm2 is 16.65mΩcm2, which is better than that of a-C 304SS. The SEM and TEM results reveal the interlock structure between the Cr interlayer and a-C film. This structure results in excellent corrosion resistance, corrosion potential of −0.32V, and corrosion current density of 0.894μAcm−2 in the simulated proton exchange membrane fuel cell (PEMFC). Single cell tests show that the peak power density of Cr/a-C 304SS PEMFC is 1.123Wcm−2, with no observed degradation during 12h lifetime tests. Thus, the Cr/a-C film is an ideal protective layer for 304SS bipolar plates of PEMFC.
•Cr/a-C film was prepared for 304SS bipolar plate of PEMFC.•The corrosion resistance and current conductivity are greatly improved.•The assembled Cr/a-C 304SS PEMFC shows better performance and stability.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Abstract
Blazars are a subject of intense debate, specifically regarding their jet launch and emission mechanisms, and the origins of their
γ
-ray radiation. To explore these issues, we have built a ...comprehensive sample of flat-spectrum radio quasars (FSRQs), with well-characterized spectral energy distribution. This study aims to elucidate the dominant jet launch mechanism and the main processes behind the inverse Compton (IC) component. Additionally, we seek to pinpoint the location of the
γ
-ray dissipation region relative to the central black hole, denoted as
R
γ
. Our approach involves a detailed analysis of broad-line region (BLR) emission, from which we derive robust estimates of the black hole masses using two distinct virial techniques. This enables us to constrain the jet power across a wide array of FSRQs. Our findings lead to several significant conclusions: (i) The correlation of jet power with black hole mass allows us to test the Blandford–Znajek, Blandford–Payne, and hybrid mechanisms. We find that the hybrid mechanism is most effective in explaining the jet power observed in the majority of FSRQs; (ii) The IC component of the
γ
-rays in FSRQs is predominantly due to the external Compton process. (iii) Through simulations, we determine the minimum and maximum values of
R
γ
(the
γ
-ray dissipation region) and conclude it is located outside the BLR. This conclusion is derived from the variability timescale analysis.
Background: Various factors can modify the health effects of outdoor air pollution. Prior findings about modifiers are inconsistent, and most of these studies were conducted in developed countries. ...Objectives: We conducted a time-series analysis to examine the modifying effect of season, sex, age, and education on the association between outdoor air pollutants particulate matter < 10 μm in aerodynamic diameter (PM₁₀), sulfur dioxide, nitrogen dioxide, and ozone and daily mortality in Shanghai, China, using 4 years of daily data (2001-2004). Methods: Using a natural spline model to analyze the data, we examined effects of air pollution for the warm season (April-September) and cool season (October-March) separately. For total mortality, we examined the association stratified by sex and age. Stratified analysis by educational attainment was conducted for total, cardiovascular, and respiratory mortality. Results: Outdoor air pollution was associated with mortality from all causes and from cardio-respiratory diseases in Shanghai. An increase of 10 μg/m³ in a 2-day average concentration of PM₁₀, SO₂, NO₂, and O₃ corresponds to increases in all-cause mortality of 0.25% 95% confidence interval (CI), 0.14-0.37), 0.95% (95% CI, 0.62-1.28), 0.97% (95% CI, 0.66-1.27), and 0.31% (95% CI, 0.04-0.58), respectively. The effects of air pollutants were more evident in the cool season than in the warm season, and females and the elderly were more vulnerable to outdoor air pollution. Effects of air pollution were generally greater in residents with low educational attainment (illiterate or primary school) compared with those with high educational attainment (middle school or above). Conclusions: Season, sex, age, and education may modify the health effects of outdoor air pollution in Shanghai. These findings provide new information about the effects of modifiers on the relationship between daily mortality and air pollution in developing countries and may have implications for local environmental and social policies.
Full text
Available for:
BFBNIB, DOBA, IZUM, KILJ, NMLJ, NUK, OILJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK, VSZLJ
Abstract
In this work, we obtained a sample of 979 Fermi blazars with broad emission lines, including 701 objects collected from published works and 278 objects developed in this work. For the 278 ...objects, we made a crossmatch from three catalogs, the Fermi Large Area Telescope Fourth Source Catalog (4FGL), the Sloan Digital Sky Survey, and the Large Sky Area Multi-Object Fiber Spectroscopic Telescope, and calculated the broad-line region (BLR) luminosity. Then, we estimated the Doppler factor and studied the correlations between the BLR luminosities and the
γ
-ray luminosities, the synchrotron peak frequency (
ν
p
), and Doppler factor (
δ
) for the whole sample. Our analyses and discussions came to the following main conclusions: For the 278 blazars, their BLR luminosity (log
L
BLR
) ranges from 40.44 to 45.45 erg s
−1
, with a mean value of 43.39 erg s
−1
. The Doppler factor ranges from
δ
= 0.45 to
δ
= 88.52, with a mean value of 12.99 for the 979 Fermi blazars, which is consistent with the results in the literature. Both the BLR luminosity and the Doppler factor exhibit positive correlations with the
γ
-ray luminosity. The BLR luminosity is anticorrelated with synchrotron peak frequency, implying a Compton cooling. A line of
log
L
BLR
=
1.58
log
ν
p
−
19.46
separating BL Lacertae objects and flat-spectrum radio quasars was obtained in the diagram of
log
L
BLR
against
log
ν
p
using a machine-learning method. Based on the analysis of the equivalent width and the Doppler factors, we proposed five changing-look blazar candidates.
This paper proposes a unified and efficient direct probability integral method (DPIM) to calculate the probability density function (PDF) of responses for linear and nonlinear stochastic structures ...under static and dynamic loads. Firstly, based on the principle of probability conservation, the probability density integral equation (PDIE) equivalent to the probability density differential equation is derived for stochastic system. We highlight that, for time dependent stochastic system the PDIE is satisfied at each time instant. Secondly, the novel DPIM is proposed to solve PDIE directly by means of the point selection technique based on generalized F discrepancy and the smoothing of Dirac delta function. Moreover, the difference and connection among the DPIM, the existing probability density evolution method and probability transformation method are examined. Finally, four typical examples for stochastic response analysis, including the linear and nonlinear systems subjected to static and dynamic loads, demonstrate the high computational efficiency and accuracy of proposed DPIM.
•Direct probability integral method is proposed based on probability conservation.•Probability density integral equation is satisfied at each instant of dynamic system.•Typical examples indicate high efficiency and accuracy of the proposed method.•The present method facilitates stochastic response analysis of general systems.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•A unified framework of static/dynamic reliability analysis is established based on direct probability integral method (DPIM).•New formula to determine smoothing parameter of Dirac function is ...suggested.•Two DPIM-based approaches for dynamic reliability analysis are proposed.•Example of nonlinear dynamic structure indicates superiority of unified framework.
Generally, the static and dynamic reliabilities of structures are addressed separately in the existing methods except the computationally expensive stochastic sampling-based approaches. This study establishes a unified framework of reliability analysis for static and dynamic structures based on the direct probability integral method (DPIM). Firstly, the probability density integral equations (PDIEs) of performance functions for static and dynamic structures are presented based on the principle of probability conservation. The DPIM decouples the physical mapping (i.e., performance function) of structure and PDIE, and involves the partition of probability space and the smoothing of Dirac delta function. This study proposes a new adaptive formula of smoothing parameter based on kernel density estimation. Then, the improved DPIM is utilized to obtain the probability density function (PDF) of performance functions by solving the corresponding representative values and the PDIE successively. Furthermore, the reliability of static structure is calculated by integrating the PDF of performance function within safety domain. To overcome the difficulty of evaluating first passage dynamic reliability, the two approaches, namely the DPIM-based absorbing condition (DPIM-AC) and the DPIM-based extreme value distribution (DPIM-EVD), are also proposed. Finally, three engineering examples with stochastic parameters and random excitation indicate the desired efficiency and accuracy of the established framework for unified reliability analysis. Specifically, the challenging issue of dynamic reliability assessment for nonlinear structural system is attacked based on DPIM rather than Monte Carlo simulation or other sampling-based method. The proposed method is beneficial for propagation analysis of aleatory or/and epistemic uncertainties, as well as for stochastic model updating.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
To evaluate the relationship between subfoveal choroidal thickness (SFCT) and eyes with central serous chorioretinopathy (CSC) versus fellow or control eyes.
We performed a meta-analysis using ...databases including PubMed, Embase and ISI Web of Science to find relevant studies. Weighted mean difference (WMD) was calculated for the SFCT in CSC eyes, the unaffected fellow eyes and normal controls.
Twelve studies were selected for this meta-analysis, including 1108 eyes (397 CSC eyes, 228 unaffected fellow eyes and 483 eyes of normal controls). The meta-analysis clearly demonstrated that the subfoveal choiroid of eyes with a clinical presentation of CSC was thickened compared to unaffected fellow eyes (WMD = 52.81, 95% confidence interval (CI), 39.13-66.49, P<0.00001) and was thickened compared to control eyes (WMD = 145.03, 95%CI, 121.33-168.73, P<0.00001). The mean SFCT measurement of the unaffected fellow eyes showed also significantly increased choroidal thickness compared to that of normal control eyes (WMD = 77.20, 95% CI, 44.98-109.42, P<0.00001). Similar results were obtained in a sub-analysis based on the same instrument.
It is demonstrated that SFCT is significantly increased in eyes with clinical manifestation of CSC, and in the clinically non-manifested fellow eyes. These results support the hypothesis that CSC is a bilateral disorder with an initial unilateral clinical presentation.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
PDF
