A Multi-Level Operation Method for Improving the Resilience of Power Systems under Extreme Weather through Preventive Control and a Virtual Oscillator.

This paper proposes a multi-level operation method designed to enhance the resilience of power systems under extreme weather conditions by utilizing preventive control and virtual oscillator (VO) technology. Firstly, a novel model for predicting time intervals between successive failures of the power system during extreme weather is introduced. Based on this, this paper proposes a preventive control method considering the system ramping and transmission constraints prior to failures so as to ensure the normal electricity demand within the system. Further, a VO-based adaptive frequency control strategy is designed to accelerate the regulation speed and eliminate the frequency deviation. Finally, the control performance is comprehensively compared under different experimental conditions. The results verify that the method accurately predicted the time of the line fault occurrence, with a maximum error not exceeding 3 min compared to the actual occurrence; also, the virtual oscillator control (VOC) strategy outperformed traditional droop control in frequency stabilization, achieving stability within 2 s compared to the droop control's continued fluctuations beyond 20 s. These results highlight VOC's superior effectiveness in frequency stability and control in power systems.

Optimization of Flow Channels in a PEM Fuel Cell Based on a Multiobjective Evaluation.

Proton exchange membrane fuel cells (PEMFCs) are known for their cleanliness and high efficiency. However, the limited energy density and high cost are the main obstacles to this technology. This study aims to overcome these challenges and enhance the overall performance of the PEMFC. Five types of PEMFCs with different blockages are proposed and simulated in this study. Afterward, the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) method is performed as a multiobjective evaluation. This study shows that the nozzle effect in the channel enhances the mass transfer of PEMFC and improves water and thermal management, resulting in a reduction of liquid water by up to 35.8%. The blockages benefit the output performance of the PEMFC. For example, the elliptical blockage shows the highest improvement in electrochemical conversion efficiency at 3.42%. The TOPSIS examines indices of power, exergy, economy, environment, and water and thermal management. The multiobjective evaluation shows that the elliptical blockage is more beneficial for PEMFC. This study provides an optimized design of the PEMFC flow channel and a new perspective to evaluate the structural improvement of PEMFC.

"One body and two wings" novel nanozyme combined with photothermal therapy for Combat Drug-Resistant Bacteria.

Bacterial resistance caused by antibiotic therapy is a serious problem. Therefore, there is an urgent need to find alternative methods to overcome bacterial resistance. Herein, we synthesized a new type of iridium oxide (IrOx) as an alternative to antibiotics. Iridium oxide not only has good catalytic properties, but also has photothermal properties, and then realizes the "one body and two wings" strategy to enhance the antibacterial effect. Research results show that near-infrared light can enhance the peroxidase catalytic activity of IrOx and generate highly toxic hydroxyl radicals (·OH) by catalyzing hydrogen peroxide (H2O2). Hydroxyl radicals have a high redox potential, which can overcome the drug resistance of gram-positive and negative bacteria. Importantly, IrOx has no obvious cellular and in vivo toxicity. Accordingly, the novel photothermal nanozyme is expected to be applied to bacterial infectious diseases, such as wound healing, sepsis, and implant-related infections.

Predictive validity of the braden scale for pressure injury risk assessment in adults: A systematic review and meta-analysis.

AIM: Pressure injuries are common adverse events in clinical practice, affecting the well-being of patients and causing considerable financial burden to healthcare systems. It is therefore essential to use reliable assessment tools to identify pressure injuries for early prevention. The Braden Scale is a widely used tool to assess pressure injury risk, but the literature is currently lacking in determining its accuracy. This study aimed to evaluate the accuracy of the Braden Scale in assessing pressure injury risk. DESIGN: Systematic review and meta-analysis. METHODS: Articles published between 1973-2020 from periodicals indexed in the PubMed, EMBASE, CINAHL, Web of Science and the Cochrane Library were selected. Two reviewers independently selected the relevant studies for inclusion. Data were analysed by the STATA 15.0 and the RevMan 5.3 software. RESULTS: In total, 60 studies involving 49,326 individuals were eligible for this meta-analysis. The pooled SEN, SPE, PLR, NLR, DOR and AUC were 0.78 (95% CI: 0.74 to 0.82), 0.72 (95% CI: 0.66 to 0.78), 2.80 (95% CI: 2.30 to 3.50), 0.30 (95% CI: 0.26 to 0.35), 9.00 (95% CI: 7.00 to 13.00) and 0.82 (95% CI: 0.79 to 0.85), respectively. Subgroup analyses indicated that the AUC was higher for prospective design (0.84, 95% CI: 0.81 to 0.87), mean age <60 years (0.87, 95% CI: 0.84 to 0.90), hospital (0.82, 95% CI: 0.79 to 0.86) and Caucasian population (0.86, 95% CI: 0.82 to 0.88). In addition, 18 was found to be the optimal cut-off value. CONCLUSION: The evidence indicated that the Braden Scale had a moderate predictive validity. It was more suitable for mean age <60 years, hospitalized patients and the Caucasian population, and the cut-off value of 18 might be used for the risk assessment of pressure injuries in clinical practice. However, due to the different cut-off values used among included studies, the results had a significant heterogeneity. Future studies should explore the optimal cut-off value in the same clinical environment.

Fractional 2940-nm Er:YAG laser-assisted drug delivery of timolol maleate for the treatment of deep infantile hemangioma.

OBJECTIVE: To study the efficacy and safety of fractional 2940 nm laser-assisted drug delivery of timolol maleate 0.5% solution for the treatment of deep IHs. METHODS: In this study, 30 deep IHs were included, and a fractional 2940 nm laser was applied with 2-weeks intervals. Topical timolol maleate 0.5% was applied under occlusion for 30 min four times/day for 24 weeks. The plasma concentration of timolol maleate was monitored for 0.5 h after the first treatment. The HAS scores and the depth, lateral diameter, vertical diameter of hemangiomas were evaluated before treatment, at 8 weeks and 24 weeks of treatment, and at 4 weeks after treatment. RESULTS: Twenty-three patients (76.7%) demonstrated excellent regression, 4(13.3%) showed good response, and 3(10%) experienced moderate regression. The HAS score was declined from 3.6 ± 0.7 to 2.3 ± 0.6 at 8 weeks, and from 1.3 ± 0.5 to 0.8 ± 0.5 at 24 weeks (p < .05). Plasma timolol concentration was not detected in 11 infants, and the rest ranged from 1.580 pg/mL to 14.718 pg/mL, which were <1 ng/mL. No systemic complications were observed in any patients. CONCLUSION: Fractional 2940 nm laser-assisted drug delivery of timolol maleate 0.5% is considered to be an effective and safe method for treating deep IHs.

Association Between Prediabetes and Erectile Dysfunction: A Meta-Analysis.

Background: Diabetes has been associated with the increased risk of erectile dysfunction (ED). However, previous studies evaluating the association between prediabetes and ED showed inconsistent results. We performed a meta-analysis of observational studies to systematically evaluate the above association. Methods: Relevant observational studies were retrieved by search of PubMed, Embase, and Web of Science databases. A random-effect model which incorporated the potential intra-study heterogeneity was used for the meta-analysis. Subgroup analyses were performed to evaluate the influences of study characteristics on the outcome. Results: Nine studies (five matched case-control studies and four cross-sectional studies) were included. Age were adjusted or matched in all of the studies. Pooled results showed that compared to men with normoglycemia, men with prediabetes were associated with higher prevalence of ED (odds ratio = 1.62, 95% confidence interval: 1.28 to 2.07, P < 0.001; I2 = 78%). Subgroup analyses showed that the association was not significantly affected by definition of prediabetes, diagnostic tool for ED, or controlling of additional variables besides age (both P for subgroup difference > 0.05). However, the association between prediabetes and ED seemed to be stronger in case-control studies than that in cross-sectional studies, and in studies with younger men (mean age < 50 years) than in those with older men (mean age ≥ 50 years; both P for subgroup difference < 0.05). Conclusions: Prediabetes is associated with higher prevalence of ED, which may be independent of age of the males and may be stronger in young men.

Prevalence and risk factors of cancer-related fatigue: A systematic review and meta-analysis.

BACKGROUND: Cancer-related fatigue, one of the most frequent side-effects of cancer treatment, affects the well-being of patients. Despite the fact that the estimated prevalence and risk factors of cancer-related fatigue are widely reported, these results have not been synthesized. OBJECTIVES: To systematically assess the prevalence of cancer-related fatigue, including stratification by fatigue degree, sex, age, therapeutic method, cancer-related fatigue scales, countries, and risk factors for cancer-related fatigue. DESIGN: Systematic literature review and meta-analysis. DATA SOURCES: PubMed, Cochrane Library, Web of Science, CINAHL Plus, China Knowledge Resource Integrated Database (CNKI), Wanfang Database, Chinese Biomedical Database (CBM), and Weipu Database (VIP) were comprehensively searched for observational studies investigating the prevalence and risk factors of cancer-related fatigue from inception to March 31st, 2019. REVIEW METHODS: Original journal articles were included which met the inclusion criteria. The quality of the included studies was evaluated independently by two investigators. Meta-analysis was conducted using Stata 12.0 software package, with estimates of cancer-related fatigue from pooled using a random-effects model. RESULTS: In total, 2641 articles were screened and data from 84 studies involving 144,813 subjects were used in meta-analysis. The prevalence of cancer-related fatigue in individual studies varied from 14.03% to 100%. The pooled prevalence of cancer-related fatigue was 52% (95% confidence interval, CI: 48% to 56%, I2 = 99.7%, P < 0.0001). After controlling for confounding variables, the following risk factors were associated with cancer-related fatigue: poor performance status (odds ratio, OR = 6.58, 95% CI: 2.60 to 16.67, I2 = 75.2%, P < 0.0001), chemoradiotherapy (OR = 2.25, 95% CI: 1.90 to 2.67, I2 =0%, P<0.0001), female sex (OR = 2.07, 95% CI: 1.51 to 2.84, I2 = 41.2%, P<0.0001), insomnia (OR = 2.83, 95% CI: 1.22 to 6.57, I2 = 98.3%, P = 0.015), neuroticism (OR = 1.23, 95% CI: 1.05 to 1.43, I2 = 88.9%, P = 0.01), pain (OR = 2.64, 95% CI: 1.20 to 5.80, I2 = 95.3%, P = 0.016), and depression (OR = 2.23, 95% CI: 1.70 to 2.93, I2 = 98.1%, P < 0.0001). CONCLUSION: The current analysis indicates an overall pooled prevalence of cancer-related fatigue of 52%. Poor performance status, chemoradiotherapy, female sex, insomnia, neuroticism, pain, and depression were identified as risk factors for cancer-related fatigue. Understanding the risk factors of cancer-related fatigue can provide the healthcare personnel with the theoretical basis for the management and treatment of the patients.

Muti-component nanocomposite of nickel and manganese oxides with enhanced stability and catalytic performance for non-enzymatic glucose sensors.

A muti-component nanocomposite of nickel and manganese oxides with a uniformly dispersed microspherical structure has been fabricated by a hydrothermal synthesis method. The as-prepared nanocomposite has been employed as a sensing material for non-enzymatic glucose detection and shown excellent electrocatalytic activity, such as high sensitivities of 82.44 µA mM(-1) cm(-2) and 27.92 µA mM(-1) cm(-2) over the linear range of 0.1-1 mM and 1-4.5 mM, respectively, a low detection limit of 0.2 µM and a fast response time of <3 s. Moreover, satisfactory specificity and excellent stability have also been achieved. The results demonstrate that a muti-component nanocomposite of nickel and manganese oxides has great potential applications as glucose sensors.

Temperature-Dependent Abnormal and Tunable p-n Response of Tungsten Oxide--Tin Oxide Based Gas Sensors.

We observed the sensing response of temperature-dependent abnormal p-n transitions in WO3-SnO2 hybrid hollow sphere based gas sensors for the first time. The sensors presented a normal n-type response to ethanol at elevated temperatures but abnormal p-type responses in a wide range of operation temperatures (room temperature to about 95 °C). By measuring various reducing gases and applying complex impedance plotting techniques, we demonstrated the abnormal p-type sensing behavior to be a pseudo-response resulting from the reaction between target gas and adsorbed water on the material surface. The temperature-controlled n-p switch is ascribed to the competition of intrinsic and extrinsic sensing behaviors, which resulted from the reaction of target gas with adsorbed oxygen ions and protons from adsorbed water, respectively. The former can modulate the intrinsic conductivity of the sensor by changing the electron concentration of the sensing materials, while the latter can regulate the conduction of the water layer, which contributes to the total conductivity as an external part. The hollow and hybrid nanostructures facilitated the observation of extrinsic sensing behaviors due to its large-area active sites and abundant oxygen vacancies, which could enhance the adsorption of water. This work might give new insight into gas sensing mechanisms and opens up a promising way to develop practical temperature and humidity controllable gas sensors with little power consumption based on the extrinsic properties.

Enhanced sensitivity and stability of room-temperature NH3 sensors using core-shell CeO2 nanoparticles@cross-linked PANI with p-n heterojunctions.

We report a room-temperature NH3 gas sensor with high response and great long-term stability, including CeO2 NPs conformally coated by cross-linked PANI hydrogel. Such core-shell nanocomposites were prepared by in situ polymerization with different weight ratios of CeO2 NPs and aniline. At room temperature, the nanohybrids showed enhanced response (6.5 to 50 ppm of NH3), which could be attributed to p-n junctions formed by the intimate contact between these two materials. Moreover, the stability was discussed in terms of phytic acid working as a gelator, which helped the PANI sheath accommodate itself and enhance the mechanical strength and chemical stability of the sensors by avoiding "swelling effect" in high relative humidity. The sensors maintained its sensing characteristic (response of ca. 6.5 to 50 ppm of NH3) in 15 days. Herein, the obtained results could help to accelerate the development of ammonia gas sensor.

Evaluation of aroma differences between high-salt liquid-state fermentation and low-salt solid-state fermentation soy sauces from China.

Two types of Chinese soy sauce, high-salt liquid-state fermentation soy sauce (HLFSS) and low-salt solid-state fermentation soy sauce (LSFSS), were used to investigate their differences in aroma profile by headspace solid-phase microextraction (HS-SPME) and gas chromatography-olfactometry/mass spectrometry (GC-O/MS). Results from descriptive sensory analysis showed that the alcoholic, cooked potato-like and caramel-like attributes were significantly higher in HLFSS, while LSFSS exhibited significantly higher sour and burnt attributes. In addition, aroma extract dilution analysis (AEDA) revealed 37 and 33 odour-active regions for HLFSS and LSFSS, respectively. Ethanol, 3-methyl-1-butanol, phenylacetaldehyde, 4-ethyl-2-methoxyphenol, 2-methoxy-4-vinylphenol and 3-(methylthio)propanal detected in HLFSS showed the highest flavour dilution (FD) factors, while 3-methylbutanal, phenylacetaldehyde and ethyl propanoate possessed the highest FD factors in LSFSS. Therefore, the traditional Chinese soy sauce HLFSS contained more complex volatiles and exhibited a richer aromatic profile compared with LSFSS.

Effects of worts treated with proteases on the assimilation of free amino acids and fermentation performance of lager yeast.

The objective of this study was to investigate the changes in free amino acids (FAA) composition by supplementing three commercial proteases (Neutrase, Flavorzyme and Protamex) at the beginning of wort mashing, and monitoring the effects on the assimilation pattern of FAA and fermentation performance of lager yeast (Saccharomyces pastorianus) during normal and high gravity fermentations. Proteases supplementation significantly improved the extract yield and FAA level of mashed worts. Normal gravity worts treated with Flavorzyme and Neutrase exhibited higher fermentability, ethanol production and flavor volatiles concentration compared to the control worts, while these beneficial effects were observed in high gravity worts treated with Protamex and Neutrase. The reason for the above results is proposed to be the change in the assimilation pattern of FAA in lager yeast with increased wort gravity, especially for the improved assimilation ratios of Leu, Arg, Phe, His, Asp and Val. In normal gravity fermentations, there were strong correlations between the assimilation amounts of Lys, Leu, Arg and His and fermentability, while in high gravity fermentations, these good correlations were found with only Lys and His. The present study suggested that optimizing the composition of FAA by supplementing proteases during wort mashing was beneficial to beer brewing for improving fermentation performance of lager yeast and flavor volatiles formation.

Chemical stability of 2'-deoxy-5-methylisocytidine during oligodeoxynucleotide synthesis and deprotection.

Previous studies have encountered difficulties with degradation of some isocytidine derivatives during solid-phase synthesis and deprotection of oligonucleotides. Here we investigate the degradation of a commonly used derivative, 2'-deoxy-5-methylisocytidine, during oligodeoxynucleotide synthesis and deprotection. A small, but detectable amount of hydrolytic deamination occurred at ca. 0.5% of 2'-deoxy-5-methylisocytidine residues using routine synthesis and deprotection conditions. Depyrimidination, or cleavage of the glycosylic bond, occurred to a far lesser extent during alkaline deprotection than previously suggested. In contrast to model studies of nucleoside monomers, significant depyrimidination was not observed, even at extended incubation times.