Heteroatom doped atomically dispersed Fe1‐NC catalysts have been found to show excellent activity toward oxygen reduction reaction (ORR). However, the origin of the enhanced activity is still ...controversial because the structure‐function relationship governing the enhancement remains elusive. Herein, sulfur(S)‐doped Fe1‐NC catalyst was obtained as a model, which displays a superior activity for ORR towards the traditional Fe‐NC materials. 57Fe Mössbauer spectroscopy and electron paramagnetic resonance spectroscopy revealed that incorporation of S in the second coordination sphere of Fe1‐NC can induce the transition of spin polarization configuration. Operando 57Fe Mössbauer spectra definitively identified the low spin single‐Fe3+‐atom of C‐FeN4‐S moiety as the active site for ORR. Moreover, DFT calculations unveiled that lower spin state of the Fe center after the S doping promotes OH* desorption process. This work elucidates the underlying mechanisms towards S doping for enhancing ORR activity, and paves a way to investigate the function of broader heteroatom doped Fe1‐NC catalysts to offer a general guideline for spin‐state‐determined ORR.
The enhanced oxygen reduction reaction (ORR) activity of sulfur‐doped Fe‐N‐C single‐atom catalysts is studied from Fe spin‐state tuning. Operando 57Fe Mössbauer spectra monitoring further supported the low‐spin (LS) single‐Fe3+‐atom of the C‐FeN4‐S moiety as the active site for the ORR.
Context
The flipped classroom (FC), reversing lecture and homework elements of a course, is popular in medical education. The FC uses technology‐enhanced pre‐class learning to transmit knowledge, ...incorporating in‐class interaction to enhance higher cognitive learning. However, the FC model is expensive and research on its effectiveness remains inconclusive. The aim of this study was to compare the efficacy of the FC model over traditional lecture‐based (LB) learning by meta‐analysis.
Methods
We systematically searched MEDLINE, PubMed, ERIC, CINAHL, EMBASE, reference lists and Association for Medical Education in Europe (AMEE) conference books. Controlled trials comparing academic outcomes between the FC and LB approaches in higher education were considered eligible. The main findings were pooled using a random‐effects model when appropriate.
Results
Forty‐six studies (9026 participants) were included, comprising four randomised controlled trials (RCTs), 19 quasi‐experimental studies and 23 cohort studies. Study populations were health science (n = 32) and non health science (n = 14) students. The risk of bias was high (36/37 articles). Meta‐analyses revealed that the FC had significantly better outcomes than the LB method in examination scores (post‐intervention and pre–post change) and course grades, but not in objective structured clinical examination scores. Subgroup analyses showed the advantage of the FC was not observed in RCTs, non‐USA countries, nursing and other health science disciplines and earlier publication years (2013 and 2014). Cumulative analysis and meta‐regression suggested a tendency for progressively better outcomes by year. Outcome assessments rarely focused on behaviour change.
Conclusions
The FC method is associated with greater academic achievement than the LB approach for higher‐level learning outcomes, which has become more obvious in recent years. However, results should be interpreted with caution because of the high methodological diversity, statistical heterogeneity and risk of bias in the studies used. Future studies should have high methodological rigour, a standardised FC format and utilise assessment tools evaluating higher cognitive learning and behaviour change to further examine differences between FC and LB learning.
The authors’ meta‐analysis (46 studies, >9000 participants, health and non‐health science education) found flipped classrooms generally have significantly better learning outcomes than lecture learning, with a tendency for better outcomes for more recent studies.
Introduction In very low birth weight (VLBW) infants, hypothermia immediately following birth is common even in countries rich in medical resources. The purpose of this study is to design a standard ...prevention bundle that decreases the rate of hypothermia among infants after birth and to investigate efficacy of the bundle and short-term outcomes for VLBW infants. Methods This quality improvement project was conducted from February 2017 to July 2018 on all VLBW preterm infants admitted at a single referral level III neonatal intensive care unit. The infants were classified into the pre-intervention (February to September 2017) and post-intervention (October 2017 to July 2018) groups according to the time periods when they were recruited. During the pre-intervention period, we analyzed the primary causes of hypothermia, developed solutions corresponding to each cause, integrated all solutions into a prevention bundle, and applied the bundle during the post-intervention period. Afterwards, the incidence of neonatal hypothermia and short-term outcomes, such as intraventricular hemorrhage (IVH), acidosis, and shock requiring inotropic agents, in each group were compared. Results A total of 95 VLBW infants were enrolled in the study, including 37 pre-intervention, and 58 post-intervention cases. The incidence of hypothermia in preterm infants decreased significantly upon the implementation of our prevention bundle, both in the delivery room (from 45.9% to 8.6%) and on admission (59.5% to 15.5%). In addition, the short-term outcomes of VLBW infants improved significantly, especially with the decreased incidence of IVH (from 21.6% to 5.2%, P = 0.015). Conclusions Our standardized prevention bundle for preventing hypothermia in VLBW infants is effective and decreased the IVH rate in VLBW infants. We strongly believe that this prevention bundle is a simple, low-cost, replicable, and effective tool that hospitals can adopt to improve VLBW infant outcomes.
Esophageal atresia with/without tracheoesophageal fistula (EA/TEF) is a congenital digestive tract anomaly that represents a major therapeutic challenge. Postoperative digestive morbidities such as ...gastroesophageal reflux disease (GERD) and esophageal stricture are common. The aim of this study was to identify the incidence of and potential risk factors for digestive morbidities after EA/TEF repair. We retrospectively reviewed all EA/TEF patients who underwent repair at a single institution between January 1999 and December 2018, excluding patients who died prior to discharge. Patient demographics, perioperative management, and postoperative GERD and esophageal stricture rates were collected. We performed univariate and multivariate analyses to examine risk factors associated with postoperative GERD and esophageal stricture. The study enrolled 58 infants (58.6% male, 17.2% with type A EA/TEF, 62.1% with associated anomalies). Postoperative GERD occurred in 67.2% of patients and was the most common digestive morbidity. Esophageal stricture occurred in 37.9% of patients after EA/TEF repair. Multivariate analysis showed that long-gap EA/TEF and postoperative GERD were independent risk factors for esophageal stricture after repair surgery.
Conclusion
: The incidence of postoperative GERD and esophageal stricture was 67.2% and 37.9%, respectively. The risk factors for postoperative esophageal stricture were long-gap EA/TEF and postoperative GERD.
What is Known:
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EA/TEF is a congenital digestive tract anomaly with a high postoperative survival rate but can be complicated by many long-term morbidities.
What is New:
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Long-gap EA/TEF and postoperative GERD are risk factors of anastomotic stricture after repair.
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Surgeons and pediatricians should be highly experienced in managing anastomotic tension and the GERD.
Chloramphenicol (CAP) is a veterinary antibiotic that has been banned due to its severe side effects in humans. Through the application of manure, veterinary antibiotics can enter the soil, where ...they can be taken up by crops and vegetables and pose a potential health hazard to humans. Thus, it is highly desirable to develop a rapid and sensitive tool for on‐site detection of CAP to ensure food safety and to control the abuse of antibiotics. To this end, nitrogen‐doped graphene quantum dots (N‐GQDs) were successfully prepared via microwave‐assisted synthesis using citric acid and urea as carbon and nitrogen sources, respectively. Analytical results suggested that the interaction between N‐GQDs and CAP could occurs via π‐π stacking, which quenched N‐GQD fluorescence. CAP spiked into chicken feed could be rapidly extracted with ethanol and quantified based on N‐GQD fluorescence quenching without further separation. This method showed good recovery (97–102.6%), a low detection limit (1.8 ppm), and was not affected by interference from florfenicol, and thiamphenicol, legal substitute antibiotics. This method has excellent potential for determination of CAP in livestock feed and soil.
Nitrogen‐doped graphene quantum dots (N‐GQDs) were successfully prepared using citric acid and urea as carbon and nitrogen sources in a microwave‐assisted synthesis. Interaction between N‐GQDs and chloramphenicol (CAP) could occur via π‐π stacking and caused N‐GQD fluorescence quenching. This method has potential for determination of CAP in chicken feed and soil.
Tyrosinase inhibitors from natural products have applications in the pharmaceutical, food, and cosmetic industries because of the functions of tyrosinase in skin disorders and in the enzymatic ...browning of fruits. Current in vitro inhibitor screening assays are based on the inhibition of the oxidation of l‐3,4‐dihydroxyphenylalanine (l‐DOPA) mediated by a mushroom tyrosinase. However, in these assays, a tyrosinase inhibitor or an antioxidant could inhibit dopaquinone formation. In this study, we aimed to eliminate this ambiguity by using a microplate assay integrating tyrosinase‐immobilized magnetic nanoparticles (TYR‐MNPs) and a homemade magnetic microplate for high‐throughput screening. After incubating extracts of natural products with TYR‐MNPs, the magnetic nanoparticles are attracted to the bottoms of wells, the extracts are rinsed, and TYR‐MNPs react with l‐DOPA. This method can be used to screen compounds that interact with the active sites of the enzyme, or copper chelators that bind more strongly than tyrosinase to copper ions, distinguishing them from antioxidants or tyrosinase substrates. Integration with the homemade magnetic microplate enables high‐throughput inhibitor screening. Aloe vera flowers are crop by‐products, and litchi flowers fall after the blossom. Our work demonstrated that these flowers have tyrosinase inhibitory effects, thus increasing their value.
This study represents the first reported use of tyrosinase‐immobilized magnetic nanoparticles and 96‐well microplates for quickly screening tyrosinase inhibitors. The core technology is the homemade magnetic microplate. With our novel method, only true inhibitors are identified without interference from antioxidants, and with additional steps, we can identify whether the inhibitor is a copper ion chelator or a specific enzyme binder.
Aim:
The aim of this study was to establish whether non-vitamin K antagonist oral anticoagulants (NOACs) are superior to warfarin in preventing stroke recurrence for atrial fibrillation (AF) patients ...with an ischemic or hemorrhagic stroke at the baseline.
Methods:
From 1 January 2009 to 31 December 2017, stroke patients with AF treated with oral anticoagulants in the National Health Insurance Research Database in Taiwan were enrolled. The study was retrospective cohort design. Outcome measures were ischemic and hemorrhagic stroke recurrence. The Cox proportional hazard model was used to obtain the hazard ratio (HR).
Results:
In total, 39,840 stroke patients with AF treated with NOAC and 42,583 treated with warfarin were identified. NOACs were superior to warfarin in preventing all recurrent stroke adjusted HR: 0.67, 95% confidence interval (CI), 0.63–0.71, p < 0.001. Results for the ischemic stroke population were the same as that for all types for stroke (adjusted HR: 0.66, 95% CI, 0.62–0.70, p < 0.001). For the hemorrhagic stroke population, NOACs were equivalent to warfarin in preventing ischemic stroke (adjusted HR: 1.11, 95% CI, 0.86–0.43, p < 0.001), but NOACs were superior to warfarin in preventing hemorrhagic stroke (adjusted HR: 0.64, 95% CI, 0.55–0.74, p < 0.001).
Conclusions:
NOACs were generally superior to warfarin in terms of efficacy and safety in previous stroke patients. The robustness of our findings was verified and should add new information to current recommendations for Asian stroke patients in selecting NOACs.
We previously reported that acute inhibition of the RhoA/Rho kinase (ROCK) pathway normalized contractile function of diabetic rat hearts, but the underlying mechanism is unclear. Protein kinase C ...(PKC) β(2) has been proposed to play a major role in diabetic cardiomyopathy at least in part by increasing oxidative stress. Further evidence suggests that PKC positively regulates RhoA expression through induction of inducible nitric oxide synthase (iNOS) in diabetes. However, in preliminary studies, we found that inhibition of ROCK itself reduced RhoA expression in diabetic hearts. We hypothesized that there is an interaction between RhoA/ROCK and PKCβ(2) in the form of a positive feedback loop that sustains their activation and the production of reactive oxygen species (ROS). This was investigated in cardiomyocytes isolated from diabetic and control rat hearts, incubated with or without cytochalasin D or inhibitors of ROCK, RhoA, PKCβ(2), or iNOS. Inhibition of RhoA and ROCK markedly attenuated the diabetes-induced increases in PKCβ(2) activity and iNOS and RhoA expression in diabetic cardiomyocytes, while having no effect in control cells. Inhibition of PKCβ(2) and iNOS also normalized RhoA expression and ROCK overactivation, whereas iNOS inhibition reversed the increase in PKCβ(2) activity. Each of these treatments also normalized the diabetes-induced increase in production of ROS. Actin cytoskeleton disruption attenuated the increased expression and/or activity of all of these targets in diabetic cardiomyocytes. These data suggest that, in the diabetic heart, the RhoA/ROCK pathway contributes to contractile dysfunction at least in part by sustaining PKCβ(2) activation and ROS production via a positive feedback loop that requires an intact cytoskeleton.
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•Using Au nanoplates in SERS sensing toward a typical PAH pollutant is demonstrated.•Significantly enhanced SERS activities and extremely low detection limit is achieved.•The SERS ...activity of Au nanoplates can be fully recovered after repeatedly used.
With the structural advantages of being sharp and straight, Au nanoplates may work as a promising surface-enhanced Raman scattering (SERS) platform for detection of Raman-sensitive analytes. However, the utilization of Au nanoplates as realistic SERS substrates is still not widely investigated, especially in the practical detection of environmentally persistent pollutants. This work delivers the first successful demonstration of using Au nanoplate platform in practical SERS sensing toward a typical polycyclic aromatic hydrocarbons pollutant of pyrene. The samples were prepared using an environmentally benign seed-mediated growth approach without the post-purification treatment. It was found that Au nanoplates exhibited significantly enhanced SERS activities (enhancement factor=7.30×107) and achieved an extremely low detection limit (5×10−10M) toward pyrene molecules. Furthermore, the SERS activity of Au nanoplates can be fully recovered after repeatedly used and recycled in pyrene detection. These results manifest that the present Au nanoplates can serve as robust, recyclable SERS substrates that allow rapid detection of trace levels of analytes with a high degree of sensitivity and stability. The findings from this work may facilitate the use of Au nanoplate SERS substrates in more realistic applications such as biomolecule sensing and environmental monitoring.
A high-throughput and selective method for the determination of ʟ-dopa (levodopa) in complex formulations was developed. The method is based on the oxidation of ʟ-dopa to yield dopachrome using ...tyrosinase-labeled magnetic nanoparticles (TYR-MNPs) as the oxidation catalyst. TYR-MNP activity was retained at 75% after 20 reuse cycles, which is superior to previously reported systems that employ other substrates or cross-linkers for the immobilization of tyrosinase. In addition, the precision (< 3%), accuracy (recovery = 95-102%), and selectivity of the newly developed quantitative-analysis method for ʟ-dopa in complex polypill formulations meets the pharmaceutical industry's quality-control requirements; consequently this method can be applied to the routine analysis of complex formulations. The quality-control assay uses 96-well microplates, which reduces the required volume of reagents, and the tyrosinase can easily be recycled and reused using an in-house-prepared magnetic microplate, thereby rendering the proposed method economical and less wasteful than existing methods.
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