Photocatalysis is regarded as one of the most promising technologies for indoor volatile organic compounds (VOCs) elimination due to its low cost, safe operation, energy efficiency, and high ...mineralization efficiency under ambient conditions. However, the practical applications of this technology are limited, despite considerable research efforts in recent decades. Until now, most of the works were carried out in the laboratory and focused on exploring new catalytic materials. Only a few works involved the immobilization of catalysts and the design of reactors for practical applications. Therefore, this review systematically summarizes the research and development on photocatalytic oxidation (PCO) of VOCs, with emphasis on recent catalyst’s immobilization and reactor designs in detail. First, different types of photocatalytic materials and the mechanisms for PCO of VOCs are briefly discussed. Then, both the catalyst’s immobilization techniques and reactor designs are reviewed in detail. Finally, the existing challenges and future perspectives for PCO of VOCs are proposed. This work aims to provide updated information and research inspirations for the commercialization of this technology in the future.
Nearly 100% HCHO conversion was obtained over the reduced Pt/TiO
2 catalysts even with 0.1% Pt loading. Metallic Pt rather than cationic Pt nanoparticles are the active centers for HCHO oxidation.
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► Highly active Pt/TiO
2 catalysts were developed by NaBH
4 reduction. ► Nearly 100% HCHO conversion was obtained over the reduced 0.1% Pt/TiO
2 catalyst. ► Metallic Pt nanoparticles provide the active sites for HCHO oxidation. ► The TOFs are not sensitive to the reducibility of support but to Pt particle sizes.
A series of highly active supported Pt catalysts, developed by sodium borohydride reduction under mild preparation conditions, were used to eliminate indoor formaldehyde (HCHO) at ambient temperature. The influences of oxidation state, support and size of Pt particles, and the operating parameters were investigated. The reduced Pt nanoparticles with different supports are highly active for catalytic oxidation of HCHO. For example, nearly 100% HCHO conversion was obtained on the reduced Pt/TiO
2 catalysts (denoted as Pt–TiO
2) even with 0.1% Pt loading while it was less than 25% on the oxidized ones. Negatively charged metallic Pt nanoparticles, which probably facilitate the electron transfer and formation of active oxygen, provide the active sites for HCHO oxidation. The turnover frequencies (TOFs) of HCHO oxidation on Pt nanoparticles with different supports are not sensitive to the reducibility of support but somewhat affected by the Pt particle sizes. A maximum TOF of 2.87
s
−1 was obtained on the 1% Pt–MgO with Pt particle size of about 3
nm. The 0.1% Pt–TiO
2 catalyst remained highly active and stable in humid air with a wide gas hourly space velocity range between 40,000 and 240,000
h
−1 and initial HCHO concentration range between 5 and 30
ppm.
It is uncertain whether aspirin therapy should be continued after endoscopic hemostatic therapy in patients who develop peptic ulcer bleeding while receiving low-dose aspirin.
To test that continuing ...aspirin therapy with proton-pump inhibitors after endoscopic control of ulcer bleeding was not inferior to stopping aspirin therapy, in terms of recurrent ulcer bleeding in adults with cardiovascular or cerebrovascular diseases.
A parallel randomized, placebo-controlled noninferiority trial, in which both patients and clinicians were blinded to treatment assignment, was conducted from 2003 to 2006 by using computer-generated numbers in concealed envelopes. (ClinicalTrials.gov registration number: NCT00153725)
A tertiary endoscopy center.
Low-dose aspirin recipients with peptic ulcer bleeding.
78 patients received aspirin, 80 mg/d, and 78 received placebo for 8 weeks immediately after endoscopic therapy. All patients received a 72-hour infusion of pantoprazole followed by oral pantoprazole. All patients completed follow-up.
The primary end point was recurrent ulcer bleeding within 30 days confirmed by endoscopy. Secondary end points were all-cause and specific-cause mortality in 8 weeks.
156 patients were included in an intention-to-treat analysis. Three patients withdrew from the trial before finishing follow-up. Recurrent ulcer bleeding within 30 days was 10.3% in the aspirin group and 5.4% in the placebo group (difference, 4.9 percentage points 95% CI, -3.6 to 13.4 percentage points). Patients who received aspirin had lower all-cause mortality rates than patients who received placebo (1.3% vs. 12.9%; difference, 11.6 percentage points CI, 3.7 to 19.5 percentage points). Patients in the aspirin group had lower mortality rates attributable to cardiovascular, cerebrovascular, or gastrointestinal complications than patients in the placebo group (1.3% vs. 10.3%; difference, 9 percentage points CI, 1.7 to 16.3 percentage points).
The sample size is relatively small, and only low-dose aspirin, 80 mg, was used. Two patients with recurrent bleeding in the placebo group did not have further endoscopy.
Among low-dose aspirin recipients who had peptic ulcer bleeding, continuous aspirin therapy may increase the risk for recurrent bleeding but potentially reduces mortality rates. Larger trials are needed to confirm these findings.
Pregnant women infected by the pandemic influenza A (H1N1) 2009 virus had more severe disease and higher mortality but its pathogenesis is still unclear.
We showed that higher mortality, more severe ...pneumonitis, higher pulmonary viral load, lower peripheral blood T lymphocytes and antibody responses, higher levels of proinflammatory cytokines and chemokines, and worse fetal development occurred in pregnant mice than non-pregnant controls infected by either wild type (clinical isolate) or mouse-adapted mutant virus with D222G substitution in hemagglutinin. These disease-associated changes and the lower respiratory tract involvement were worse in pregnant mice challenged by mutant virus. Though human placental origin JEG-3 cell line could be infected and proinflammatory cytokines or chemokines were elevated in amniotic fluid of some mice, no placental or fetal involvement by virus were detected by culture, real-time reverse transcription polymerase chain reaction or histopathological changes. Dual immunofluorescent staining of viral nucleoprotein and type II alveolar cell marker SP-C protein suggested that the majority of infected alveolar epithelial cells were type II pneumocytes.
The adverse effect of this pandemic virus on maternal and fetal outcome is largely related to the severe pulmonary disease and the indirect effect of inflammatory cytokine spillover into the systemic circulation.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Hydrogen production by a proton exchange membrane (PEM) electrolyzer provides a promising way to store and better utilize the renewable energy resources. Presently, theoretical studies on PEM ...electrolyzer are still limited, impeding its technological development. Detailed thermodynamic analysis is valuable to identify the key losses and to optimise the performance of PEM electrolyzer plant for hydrogen production. In this study, energy and exergy analysis has been conducted to investigate the thermodynamic-electrochemical characteristics of hydrogen production by a PEM electrolyzer plant. One important feature of this model is that detailed electrochemical characteristics of the PEM electrolyzer are fully incorporated into the thermodynamic analysis.
Heat production in the PEM cell due to irreversible losses has been investigated and compared with the thermal energy demand of PEM cell. It is found that a PEM electrolyzer normally operates in an exothermic mode as the heat production due to overpotentials exceeds the thermal energy demand. As the electrical energy input dominates the overall energy input, the exergy efficiency is found about the same as the energy efficiency.
Parametric analyses have been performed to investigate the effect of important design and operating parameters on the plant energy conversion efficiency. This study has quantified how much the energy efficiency can decreases by increasing the operating temperature, lowering the current density, reducing the electrolyte thickness, and increasing the electrode catalytic activity.
The analysis presented in this paper also offers better understanding of the characteristics of PEM electrolyzer plant for hydrogen production. With additional energy analysis of electricity generated from solar cells or wind turbines, the model presented in this paper is ready for complete energy/exergy analysis of advanced renewable electrolytic hydrogen production plants.
Background
The Montreal Cognitive Assessment (MoCA) is psychometrically superior over the Mini‐mental State Examination (MMSE) for cognitive screening in stroke or transient ischemic attack (TIA). It ...is free for clinical and research use. The objective of this study is to convert scores from the MMSE to MoCA and MoCA‐5‐minute protocol (MoCA‐5 min) and to examine the ability of the converted scores in detecting cognitive impairment after stroke or TIA.
Methods
A total of 904 patients were randomly divided into training (n = 623) and validation (n = 281) samples matched for demography and cognition. MMSE scores were converted to MoCA and MoCA‐5 min using (1) equipercentile method with log‐linear smoothing and (2) Poisson regression adjusting for age and education. Receiver operating characteristics curve analysis was used to examine the ability of the converted scores in differentiating patients with cognitive impairment.
Results
The mean education was 5.8 (SD = 4.6; ranged 0–20) years. The entire spectrum of MMSE scores was converted to MoCA and MoCA‐5 min using equipercentile method. Relationship between MMSE and MoCA scores was confounded by age and education, and a conversion equation with adjustment for age and education was derived. In the validation sample, the converted scores differentiated cognitively impaired patients with area under receiver operating characteristics curve 0.826 to 0.859.
Conclusion
We provided 2 methods to convert scores from the MMSE to MoCA and MoCA‐5 min based on a large sample of patients with stroke or TIA having a wide range of education and cognitive levels. The converted scores differentiated patients with cognitive impairment after stroke or TIA with high accuracy.
In this randomized trial in patients who had ulcer bleeding while taking aspirin for prevention of vascular disease, clopidogrel was associated with a much higher rate of recurrent bleeding than the ...combination of aspirin and a proton-pump inhibitor (8.6 percent vs. 0.7 percent).
In patients who had ulcer bleeding while taking aspirin for prevention of vascular disease, clopidogrel was associated with a much higher rate of recurrent bleeding than the combination of aspirin and a proton-pump inhibitor.
It is estimated that during the past two decades 50 million Americans have started taking aspirin for the prevention of heart attack and stroke.
1
However, aspirin doubles the risk of upper gastrointestinal bleeding even at doses as low as 75 mg daily.
2
A history of upper gastrointestinal bleeding from an ulcer is the most important risk factor for subsequent upper gastrointestinal bleeding in patients taking aspirin.
3
,
4
Up to 15 percent of those taking aspirin who have a history of bleeding from ulcers had recurrent bleeding within one year.
5
Proton-pump inhibitors reduce the risk of aspirin-induced ulcer bleeding,
5
–
7
and . . .
Abstract
Ki67 immunohistochemistry (IHC), commonly used as a proliferation marker in breast cancer, has limited value for treatment decisions due to questionable analytical validity. The ...International Ki67 in Breast Cancer Working Group (IKWG) consensus meeting, held in October 2019, assessed the current evidence for Ki67 IHC analytical validity and clinical utility in breast cancer, including the series of scoring studies the IKWG conducted on centrally stained tissues. Consensus observations and recommendations are: 1) as for estrogen receptor and HER2 testing, preanalytical handling considerations are critical; 2) a standardized visual scoring method has been established and is recommended for adoption; 3) participation in and evaluation of quality assurance and quality control programs is recommended to maintain analytical validity; and 4) the IKWG accepted that Ki67 IHC as a prognostic marker in breast cancer has clinical validity but concluded that clinical utility is evident only for prognosis estimation in anatomically favorable estrogen receptor–positive and HER2-negative patients to identify those who do not need adjuvant chemotherapy. In this T1-2, N0-1 patient group, the IKWG consensus is that Ki67 5% or less, or 30% or more, can be used to estimate prognosis. In conclusion, analytical validity of Ki67 IHC can be reached with careful attention to preanalytical issues and calibrated standardized visual scoring. Currently, clinical utility of Ki67 IHC in breast cancer care remains limited to prognosis assessment in stage I or II breast cancer. Further development of automated scoring might help to overcome some current limitations.
An International Ki67 Reproducibility Study POLLEY, Mei-Yin C; LEUNG, Samuel C. Y; GOWN, Allen M ...
JNCI : Journal of the National Cancer Institute,
12/2013, Letnik:
105, Številka:
24
Journal Article
Recenzirano
Odprti dostop
In breast cancer, immunohistochemical assessment of proliferation using the marker Ki67 has potential use in both research and clinical management. However, lack of consistency across laboratories ...has limited Ki67's value. A working group was assembled to devise a strategy to harmonize Ki67 analysis and increase scoring concordance. Toward that goal, we conducted a Ki67 reproducibility study.
Eight laboratories received 100 breast cancer cases arranged into 1-mm core tissue microarrays-one set stained by the participating laboratory and one set stained by the central laboratory, both using antibody MIB-1. Each laboratory scored Ki67 as percentage of positively stained invasive tumor cells using its own method. Six laboratories repeated scoring of 50 locally stained cases on 3 different days. Sources of variation were analyzed using random effects models with log2-transformed measurements. Reproducibility was quantified by intraclass correlation coefficient (ICC), and the approximate two-sided 95% confidence intervals (CIs) for the true intraclass correlation coefficients in these experiments were provided.
Intralaboratory reproducibility was high (ICC = 0.94; 95% CI = 0.93 to 0.97). Interlaboratory reproducibility was only moderate (central staining: ICC = 0.71, 95% CI = 0.47 to 0.78; local staining: ICC = 0.59, 95% CI = 0.37 to 0.68). Geometric mean of Ki67 values for each laboratory across the 100 cases ranged 7.1% to 23.9% with central staining and 6.1% to 30.1% with local staining. Factors contributing to interlaboratory discordance included tumor region selection, counting method, and subjective assessment of staining positivity. Formal counting methods gave more consistent results than visual estimation.
Substantial variability in Ki67 scoring was observed among some of the world's most experienced laboratories. Ki67 values and cutoffs for clinical decision-making cannot be transferred between laboratories without standardizing scoring methodology because analytical validity is limited.
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