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1.
Biomed Environ Sci ; 37(4): 406-417, 2024 Apr 20.
Article in English | MEDLINE | ID: mdl-38727163

ABSTRACT

Objective: This study aimed to efficiently reduce the release of radon from water bodies to protect the environment. Methods: Based on the sizes of the experimental setup and modular float, computational fluid dynamics (CFD) was used to assess the impact of the area coverage rate, immersion depth, diffusion coefficient, and radon transfer velocity at the gas-liquid interface on radon migration and exhalation of radon-containing water. Based on the numerical simulation results, an estimation model for the radon retardation rate was constructed. The effectiveness of the CFD simulation was evaluated by comparing the experimental and simulated variation values of the radon retardation rate with the coverage area rates. Results: The effect of radon transfer velocity on radon retardation in water bodies was minor and insignificant according to the appropriate value; therefore, an estimation model of the radon retardation rate of the coverage of a radon-containing water body was constructed using the synergistic impacts of three factors: area coverage rate, immersion depth, and diffusion coefficient. The deviation between the experimental and simulated results was < 4.3%. Conclusion: Based on the numerical simulation conditions, an estimation model of the radon retardation rate of covering floats in water bodies under the synergistic effect of multiple factors was obtained, which provides a reference for designing covering floats for radon retardation in radon-containing water.


Subject(s)
Hydrodynamics , Radon , Radon/analysis , Computer Simulation , Water Pollutants, Radioactive/analysis
2.
Accid Anal Prev ; 198: 107460, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38295653

ABSTRACT

There is currently no established method for evaluating human response timing across a range of naturalistic traffic conflict types. Traditional notions derived from controlled experiments, such as perception-response time, fail to account for the situation-dependency of human responses and offer no clear way to define the stimulus in many common traffic conflict scenarios. As a result, they are not well suited for application in naturalistic settings. We present a novel framework for measuring and modeling response times in naturalistic traffic conflicts applicable to automated driving systems as well as other traffic safety domains. The framework suggests that response timing must be understood relative to the subject's current (prior) belief and is always embedded in, and dependent on, the dynamically evolving situation. The response process is modeled as a belief update process driven by perceived violations to this prior belief, that is, by surprising stimuli. The framework resolves two key limitations with traditional notions of response time when applied in naturalistic scenarios: (1) The strong situation dependence of response timing and (2) how to unambiguously define the stimulus. Resolving these issues is a challenge that must be addressed by any response timing model intended to be applied in naturalistic traffic conflicts. We show how the framework can be implemented by means of a relatively simple heuristic model fit to naturalistic human response data from real crashes and near crashes from the SHRP2 dataset and discuss how it is, in principle, generalizable to any traffic conflict scenario. We also discuss how the response timing framework can be implemented computationally based on evidence accumulation enhanced by machine learning-based generative models and the information-theoretic concept of surprise.


Subject(s)
Automobile Driving , Time Perception , Humans , Accidents, Traffic/prevention & control , Reaction Time , Heuristics
3.
Hum Factors ; 66(5): 1545-1563, 2024 May.
Article in English | MEDLINE | ID: mdl-36602523

ABSTRACT

OBJECTIVE: This study explores subjective and objective driving style similarity to identify how similarity can be used to develop driver-compatible vehicle automation. BACKGROUND: Similarity in the ways that interaction partners perform tasks can be measured subjectively, through questionnaires, or objectively by characterizing each agent's actions. Although subjective measures have advantages in prediction, objective measures are more useful when operationalizing interventions based on these measures. Showing how objective and subjective similarity are related is therefore prudent for aligning future machine performance with human preferences. METHODS: A driving simulator study was conducted with stop-and-go scenarios. Participants experienced conservative, moderate, and aggressive automated driving styles and rated the similarity between their own driving style and that of the automation. Objective similarity between the manual and automated driving speed profiles was calculated using three distance measures: dynamic time warping, Euclidean distance, and time alignment measure. Linear mixed effects models were used to examine how different components of the stopping profile and the three objective similarity measures predicted subjective similarity. RESULTS: Objective similarity using Euclidean distance best predicted subjective similarity. However, this was only observed for participants' approach to the intersection and not their departure. CONCLUSION: Developing driving styles that drivers perceive to be similar to their own is an important step toward driver-compatible automation. In determining what constitutes similarity, it is important to (a) use measures that reflect the driver's perception of similarity, and (b) understand what elements of the driving style govern subjective similarity.


Subject(s)
Automobile Driving , Humans , Surveys and Questionnaires , Automation , Accidents, Traffic
4.
Biomed Pharmacother ; 165: 115070, 2023 Sep.
Article in English | MEDLINE | ID: mdl-37390711

ABSTRACT

At present, cancer remains one of the leading causes of human death worldwide, and surgery, radiotherapy and chemotherapy are still the main methods of cancer treatment. However, these treatments have their drawbacks. Surgical treatment often struggles with the complete removal of tumor tissue, leading to a high risk of cancer recurrence. Additionally, chemotherapy drugs have a significant impact on overall health and can easily result in drug resistance. The high risk and mortality of cancer and other reasons promote scientific researchers to unremittingly develop and find a more accurate and faster diagnosis strategy and effective cancer treatment method. Photothermal therapy, which utilizes near-infrared light, offers deeper tissue penetration and minimal damage to surrounding healthy tissues. Compared to conventional radiotherapy and other treatment methods, photothermal therapy boasts several advantages, including high efficiency, non-invasiveness, simplicity, minimal toxicity, and fewer side effects. Photothermal nanomaterials can be categorized as either organic or inorganic materials. This review primarily focuses on the behavior of carbon materials as inorganic materials and their role in tumor photothermal treatment. Furthermore, the challenges faced by carbon materials in photothermal treatment are discussed.


Subject(s)
Nanoparticles , Nanostructures , Neoplasms , Humans , Photothermal Therapy , Carbon , Phototherapy/methods , Neoplasms/therapy , Neoplasms/diagnosis
5.
Brain Res ; 1811: 148393, 2023 07 15.
Article in English | MEDLINE | ID: mdl-37150340

ABSTRACT

BACKGROUND: Exertional heatstroke (EHS) is an emergency with a high mortality rate, characterized by central nervous system dysfunctions. This study aims to establish a Heat acclimation/acclimatization (HA) rat model in locomotion to recapitulate the physical state of human in severe environment of high temperature and humidity, and investigate the mechanism of organism protection in HA. (2) Methods: Wistar rats were exposed to 36 °C and ran 2 h/d for 21 days, acquired thermal tolerance test was conducted to assess the thermotolerance and exercise ability. Core temperature and consumption of water and food were observed. Expression of HSP70 and HSP90 of different tissues were determined by WB. Pathological structure of brain tissue was detected with HE staining. Proteomics was used to identify the differently expressed proteins in cerebral cortex of different groups. And key molecules were identified by RT-PCR and WB. (3) Results: HA rats displayed stronger thermotolerance and exercised ability on acquired thermal tolerance test. Brain water content of HA + EHS group reduced compared with EHS group. HE staining revealed slighter brain injuries of HA + EHS group than that of EHS. Proteomics focused on cell death-related pathways and key molecules Aquaporin 4 (AQP4) related to cell edema. Identification results showed HA increased AQP4, Bcl-xl, ratio of p-Akt/AKT and Bcl-xl/Bax, down-regulated Cleaved Caspase-3. (4) Conclusions: This HA model can ameliorate brain injury of EHS by reducing cerebral edema and cell apoptosis, offering experimental evidence for EHS prophylaxis.


Subject(s)
Brain Injuries , Heat Stroke , Humans , Rats , Animals , Proto-Oncogene Proteins c-akt , Rats, Wistar , Heat-Shock Response , Acclimatization/physiology , Exercise/physiology
6.
Mil Med Res ; 10(1): 23, 2023 05 29.
Article in English | MEDLINE | ID: mdl-37248514

ABSTRACT

Continuous renal replacement therapy (CRRT) is widely used for treating critically-ill patients in the emergency department in China. Anticoagulant therapy is needed to prevent clotting in the extracorporeal circulation during CRRT. Regional citrate anticoagulation (RCA) has been shown to potentially be safer and more effective and is now recommended as the preferred anticoagulant method for CRRT. However, there is still a lack of unified standards for RCA management in the world, and there are many problems in using this method in clinical practice. The Emergency Medical Doctor Branch of the Chinese Medical Doctor Association (CMDA) organized a panel of domestic emergency medicine experts and international experts of CRRT to discuss RCA-related issues, including the advantages and disadvantages of RCA in CRRT anticoagulation, the principle of RCA, parameter settings for RCA, monitoring of RCA (mainly metabolic acid-base disorders), and special issues during RCA. Based on the latest available research evidence as well as the paneled experts' clinical experience, considering the generalizability, suitability, and potential resource utilization, while also balancing clinical advantages and disadvantages, a total of 16 guideline recommendations were formed from the experts' consensus.


Subject(s)
Citrates , Continuous Renal Replacement Therapy , Humans , Anticoagulants/therapeutic use , Citrates/therapeutic use , Consensus , China
7.
BMJ Open ; 13(3): e061807, 2023 03 07.
Article in English | MEDLINE | ID: mdl-36882248

ABSTRACT

OBJECTIVE: To compare the efficacy and safety between and within glucagon-like peptide-1 receptor agonists (GLP-1RAs) and sodium-glucose cotransporter 2 inhibitors (SGLT-2is) in overweight or obese adults with or without diabetes mellitus. METHODS: PubMed, ISI Web of Science, Embase and Cochrane Central Register of Controlled Trials database were comprehensively searched to identify randomised controlled trials (RCTs) of effects of GLP-1RAs and SGLT-2is in overweight or obese participants from inception to 16 January 2022. The efficacy outcomes were the changes of body weight, glucose level and blood pressure. The safety outcomes were serious adverse events and discontinuation due to adverse events. The mean differences, ORs, 95% credible intervals (95% CI), the surface under the cumulative ranking were evaluated for each outcome by network meta-analysis. RESULTS: Sixty-one RCTs were included in our analysis. Both GLP-1RAs and SGLT-2is conferred greater extents in body weight reduction, achieving at least 5% wt loss, HbA1c and fasting plasma glucose decrease compared with placebo. GLP-1RAs was superior to SGLT-2is in HbA1c reduction (MD: -0.39%, 95% CI -0.70 to -0.08). GLP-1RAs had high risk of adverse events, while SGLT-2is were relatively safe. Based on intraclass comparison, semaglutide 2.4 mg was among the most effective interventions in losing body weight (MD: -11.51 kg, 95% CI -12.83 to -10.21), decreasing HbA1c (MD: -1.49%, 95% CI -2.07 to -0.92) and fasting plasma glucose (MD: -2.15 mmol/L, 95% CI -2.83 to -1.59), reducing systolic blood pressure (MD: -4.89 mm Hg, 95% CI -6.04 to -3.71) and diastolic blood pressure (MD: -1.59 mm Hg, 95% CI -2.37 to -0.86) with moderate certainty evidences, while it was associated with high risk of adverse events. CONCLUSIONS: Semaglutide 2.4 mg showed the greatest effects on losing body weight, controlling glycaemic level and reducing blood pressure while it was associated with high risk of adverse events.PROSPERO registration numberCRD42021258103.


Subject(s)
Diabetes Mellitus , Glucagon-Like Peptide-1 Receptor , Obesity , Overweight , Sodium-Glucose Transporter 2 Inhibitors , Adult , Humans , Blood Glucose , Body Weight , Glucagon-Like Peptide-1 Receptor/agonists , Glycated Hemoglobin , Network Meta-Analysis , Obesity/complications , Obesity/drug therapy , Overweight/complications , Overweight/drug therapy , Sodium-Glucose Transporter 2 Inhibitors/therapeutic use , Weight Loss
8.
Front Chem ; 10: 1069816, 2022.
Article in English | MEDLINE | ID: mdl-36451930

ABSTRACT

Graphite carbon nitride (g-C3N4), as a polymer semiconductor photocatalyst, is widely used in the treatment of photocatalytic environmental pollution. In this work, a Z-scheme g-C3N4/Ag/AgBr heterojunction photocatalyst was prepared based on the preparation of a g-C3N4-based heterojunction via in-situ loading through photoreduction method. The g-C3N4/Ag/AgBr composite showed an excellent photocatalytic performance in the degradation of tetracycline hydrochloride pollutants. Among the prepared samples, g-C3N4/Ag/AgBr-8% showed the best photocatalytic ability for the degradation of tetracycline hydrochloride, whose photocatalytic degradation kinetic constant was 0.02764 min-1, which was 9.8 times that of g-C3N4, 2.4 times that of AgBr, and 1.9 times that of Ag/AgBr. In the photocatalytic process, •O2- and •OH are main active oxygen species involved in the degradation of organic pollutants. The photocatalytic mechanism of g-C3N4/Ag/AgBr is mainly through the formation of Z-scheme heterojunctions, which not only effectively improves the separation efficiency of photogenerated electron-hole pairs, but also maintains the oxidation and reduction capability of AgBr and g-C3N4, respectively.

9.
Chemosphere ; 307(Pt 1): 135717, 2022 Nov.
Article in English | MEDLINE | ID: mdl-35863405

ABSTRACT

In this work, NiFe2O4/g-C3N4 heterostructure was prepared and used for the photocatalytic decomposition of tetracycline hydrochloride antibiotic and for inactivation of E. coli bacteria. The fabricated NiFe2O4/g-C3N4 composite displayed enhanced ability for photodegradation of organic pollutants and disinfection activities compared to the bare samples, because of the enhancement of visible light absorbance, heterojunction formation and photo-Fenton process. The optimized sample 10%-NiFe2O4/g-C3N4 has photodegraded 94.5% of tetracycline hydrochloride in 80 min. The active species trapping experiments revels that ·O2-, h+ and •OH are key decomposing species participated in the antibiotic degradation. It is hoped that the present study will provide a better understanding to fabricate efficient photocatalysts for the decomposition of organic pollutants and disinfection of bacteria.


Subject(s)
Environmental Pollutants , Tetracycline , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Catalysis , Escherichia coli , Light , Tetracycline/chemistry , Tetracycline/pharmacology
10.
Muscle Nerve ; 64(3): 336-341, 2021 09.
Article in English | MEDLINE | ID: mdl-34151436

ABSTRACT

INTRODUCTION/AIMS: Exertional rhabdomyolysis (ER) often occurs during prolonged intense exercise in hot environments, posing a threat to the health of military personnel. In this study we aimed to investigate possible risk factors for ER and provide further empirical data for prevention and clinical treatment strategies. METHODS: A retrospective investigation of 116 concurrent ER cases was conducted. Conditional logistic regression analyses were performed to assess the association between each potential risk (or protective) factor and ER. The clinical characteristics of the 71 hospitalized patients were analyzed descriptively. RESULTS: After screening, the following variables significantly increased the risk of ER: shorter length of service (recruits; odds ratios [OR], 7.49; 95% confidence interval [CI], 2.58-21.75); higher body mass index (BMI; OR, 1.14, 95% CI, 1.03-1.26); lack of physical exercise in the last half year (less than once per month; OR, 3.20; 95% CI, 1.08-9.44); and previous heat injury (OR, 2.94; 95% CI, 1.26-6.89). Frequent fruit consumption (OR, 0.57; 95% CI, 0.33-0.99), active hydration habit (OR, 0.37; 95% CI, 0.20-0.67), water replenishment of more than 2 L on the training day (OR, 0.15; 95% CI, 0.05-0.45), and water replenishment of at least 500 mL within 1 hour before training (OR, 0.33; 95% CI, 0.12-0.88) significantly decreased the risk of ER. Of the 71 hospitalized patients, 41 (57.7%) were diagnosed with hypokalemia on admission. DISCUSSION: In military training, emphasis should be placed on incremental adaptation training before more intense training, and close attention should be given to overweight and previously sedentary recruits. Fluid replenishment before exercise, increased fruit intake, and proper potassium supplementation may help prevent ER.


Subject(s)
Adaptation, Physiological/physiology , Body Mass Index , Exercise/physiology , Physical Exertion/physiology , Rhabdomyolysis/diagnosis , Adolescent , Humans , Male , Mass Screening , Military Personnel , Retrospective Studies , Rhabdomyolysis/etiology , Rhabdomyolysis/physiopathology , Risk Factors , Time Factors , Young Adult
11.
Am J Emerg Med ; 44: 366-372, 2021 06.
Article in English | MEDLINE | ID: mdl-32389399

ABSTRACT

OBJECTIVE: To evaluate the prognostic value of routine coagulation tests for patients with heat stroke. METHODS: This was a multi-center retrospective study. Patients who arrived at the hospital <24 h after the onset of Heat Stroke (HS) were included. The routine coagulation variables were detected within 24 h after the onset, including the lowest platelet count (PLC). RESULTS: 60-day mortality rate was 20.9%. The median Prothrombin Time-International Normalized Ratio (PT-INR) of the non-surviving patients was significantly higher than that of the survivors (P < 0.01). The median Activated Partial Thromboplastin Time (APTT) in non-surviving patients was significantly higher than in the surviving patients (P < 0.01). A Cox regression analysis revealed that 60-day mortality was associated with PT-INR (P = 0.032) and APTT (P = 0.004). The optimal PT-INR point for predicting 60-day mortality rate was 1.7. The optimal APTT point for predicting 60-day mortality was 51.45. Patients with increased PT-INR (≥1.7) levels had, overall, a significantly reduced survival time (P < 0.01). Patients with elevated APTT (≥51.45) also had a decrease in survival time (P < 0.01). The prognostic scoring, with increased PT-INR (≥1.7) and prolonged APTT (≥51.45) at one point each, was also demonstrated to be useful in predicting 60-day mortality. Patients whose temperature fell to 38.9 °C within 30 min had significantly lower levels of PT-INR and APTT within 24 h than those who took longer to cool down. CONCLUSIONS: A prolonged APTT and elevated PT-INR within 24 h are independent prognostic factors of 60-day mortality in HS.


Subject(s)
Blood Coagulation Tests , Heat Stroke/blood , Heat Stroke/mortality , Adult , China/epidemiology , Female , Humans , International Normalized Ratio , Male , Partial Thromboplastin Time , Prognosis , Prothrombin Time , Retrospective Studies , Survival Rate
12.
Hum Factors ; 63(2): 197-209, 2021 03.
Article in English | MEDLINE | ID: mdl-31596618

ABSTRACT

OBJECTIVE: This study examines how driving styles of fully automated vehicles affect drivers' trust using a statistical technique-the two-part mixed model-that considers the frequency and magnitude of drivers' interventions. BACKGROUND: Adoption of fully automated vehicles depends on how people accept and trust them, and the vehicle's driving style might have an important influence. METHOD: A driving simulator experiment exposed participants to a fully automated vehicle with three driving styles (aggressive, moderate, and conservative) across four intersection types (with and without a stop sign and with and without crossing path traffic). Drivers indicated their dissatisfaction with the automation by depressing the brake or accelerator pedals. A two-part mixed model examined how automation style, intersection type, and the distance between the automation's driving style and the person's driving style affected the frequency and magnitude of their pedal depression. RESULTS: The conservative automated driving style increased the frequency and magnitude of accelerator pedal inputs; conversely, the aggressive style increased the frequency and magnitude of brake pedal inputs. The two-part mixed model showed a similar pattern for the factors influencing driver response, but the distance between driving styles affected how often the brake pedal was pressed, but it had little effect on how much it was pressed. CONCLUSION: Eliciting brake and accelerator pedal responses provides a temporally precise indicator of drivers' trust of automated driving styles, and the two-part model considers both the discrete and continuous characteristics of this indicator. APPLICATION: We offer a measure and method for assessing driving styles.


Subject(s)
Automobile Driving , Trust , Accidents, Traffic/prevention & control , Automation , Autonomous Vehicles , Emotions , Humans , Reaction Time
13.
Chemosphere ; 267: 129220, 2021 Mar.
Article in English | MEDLINE | ID: mdl-33316618

ABSTRACT

This work reports a simple method to prepare nickel-phosphorus (Ni-P) alloy modified CuO (Ni-P/CuO) composite, which shows excellent performance in terms of photodegradation antibiotics, particularly regarding the antibacterial properties. The Ni-P/CuO composites were prepared via two steps. The first step was to produce CuO by the hydrothermal method and the second step was to grow Ni-P in-situ on the surface of CuO through electroless plating. After loading of Ni-P, the photocatalytic activity of CuO for the decomposition of antibiotics is significantly increased under visible light irradiation. The photocatalytic activity of Ni-P/CuO with 4 wt% Ni-P loading is 25 times higher than that of CuO. Compared with CuO, the antibacterial activity of Ni-P/CuO with 4 wt% Ni-P loading against Escherichia coli is strongly increased. Based on the photoluminescence and photocurrent measurements of CuO and Ni-P/CuO, Ni-P cocatalyst improves the separation and transfer of the photogenerated charge in CuO, and enhances the photocatalytic activity of antibacterial performance. This work reveals that using Ni-P as the cocatalyst can strengthen the photocatalytic performance of CuO, which has great application potential in water purification and antibacterial treatments.


Subject(s)
Anti-Bacterial Agents , Copper , Anti-Bacterial Agents/pharmacology , Catalysis , Photolysis
14.
Mil Med Res ; 7(1): 37, 2020 08 06.
Article in English | MEDLINE | ID: mdl-32762730

ABSTRACT

Heat stroke is the most severe type of heat illness, it is often accompanied by severe multiorgan damage and has a high fatality rate. In January 2020, based on new research evidence and the experiences of Chinese experts in heat stroke, the Expert Group of Heat Stroke Prevention and Treatment of the Chinese People's Liberation Army (PLA) and the Professional Committee of Critical Care Medicine of the Chinese PLA jointly issued a new Expert Consensus on the Diagnosis and Treatment of Heat Stroke in China. This article aims to interpret and supplement the major updates to the new consensus.


Subject(s)
Heat Stroke , Military Personnel , China , Consensus , Heat Stroke/diagnosis , Heat Stroke/therapy , Humans
15.
Mil Med Res ; 7(1): 15, 2020 04 03.
Article in English | MEDLINE | ID: mdl-32241296

ABSTRACT

Thrombocytopenia is a common complication of critical care patients. The rates of bleeding events and mortality are also significantly increased in critical care patients with thrombocytopenia. Therefore, the Critical Care Medicine Committee of Chinese People's Liberation Army (PLA) worked with Chinese Society of Laboratory Medicine, Chinese Medical Association to develop this consensus to provide guidance for clinical practice. The consensus includes five sections and 27 items: the definition of thrombocytopenia, etiology and pathophysiology, diagnosis and differential diagnosis, treatment and prevention.


Subject(s)
Thrombocytopenia/diagnosis , Thrombocytopenia/therapy , China/epidemiology , Consensus , Critical Care/methods , Critical Care/trends , Diagnosis, Differential , Humans , Thrombocytopenia/physiopathology
16.
Mil Med Res ; 7(1): 1, 2020 01 13.
Article in English | MEDLINE | ID: mdl-31928528

ABSTRACT

Heat stroke (HS) is a fatal disease caused by thermal damage in the body, and it has a very high mortality rate. In 2015, the People's Liberation Army Professional Committee of Critical Care Medicine published the first expert consensus on HS in China, Expert consensus on standardized diagnosis and treatment for heat stroke. With an increased understanding of HS and new issues that emerged during the HS treatment in China in recent years, the 2015 consensus no longer meet the requirements for HS prevention and treatment. It is necessary to update the consensus to include the latest research evidence and establish a new consensus that has broader coverage, is more practical and is more in line with China's national conditions. This new expert consensus includes new concept of HS, recommendations for laboratory tests and auxiliary examinations, new understanding of diagnosis and differential diagnosis, On-site emergency treatment and In-hospital treatment, translocation of HS patients and prevention of HS.


Subject(s)
Heat Stroke/diagnosis , Heat Stroke/therapy , China/epidemiology , Consensus , Diagnosis, Differential , Exercise/physiology , Heat Stroke/epidemiology , Hot Temperature/adverse effects , Humans
17.
Molecules ; 24(9)2019 May 08.
Article in English | MEDLINE | ID: mdl-31071946

ABSTRACT

This work incorporates a variety of conjugated donor-acceptor (DA) co-monomers such as 2,6-diaminopurine (DP) into the structure of a polymeric carbon nitride (PCN) backbone using a unique nanostructure co-polymerization strategy and examines its photocatalytic activity performance in the field of photocatalytic CO2 reduction to CO and H2 under visible light irradiation. The as-synthesized samples were successfully analyzed using different characterization methods to explain their electronic and optical properties, crystal phase, microstructure, and their morphology that influenced the performance due to the interactions between the PCN and the DPco-monomer. Based on the density functional theory (DFT) calculation result, pure PCN and CNU-DP15.0 trimers (interpreted as incorporation of the co-monomer at two different positions) were extensively evaluated and exhibited remarkable structural optimization without the inclusion of any symmetry constraints (the non-modified sample derived from urea, named as CNU), and their optical and electronic properties were also manipulated to control occupation of their respective highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO). Also, co-polymerization of the donor-acceptor 2,6-diamino-purine co-monomer with PCN influenced the chemical affinities, polarities, and acid-base functions of the PCN, remarkably enhancing the photocatalytic activity for the production of CO and H2 from CO2 by 15.02-fold compared than that of the parental CNU, while also improving the selectivity.


Subject(s)
Carbon Dioxide/chemistry , Electrons , Light , Nitriles/chemistry , Polymers/chemistry , Adsorption , Carbon-13 Magnetic Resonance Spectroscopy , Catalysis/radiation effects , Electrochemistry , Nitrogen/chemistry , Oxidation-Reduction , Photoelectron Spectroscopy , Spectrophotometry, Ultraviolet , Spectroscopy, Fourier Transform Infrared , X-Ray Diffraction
18.
Front Chem ; 7: 91, 2019.
Article in English | MEDLINE | ID: mdl-31001509

ABSTRACT

The g-C3N4 porous nanosheets with different loading amount of Ag nanoparticles (NPs) are successfully prepared by a simple liquid-phase reduction method. These Ag/g-C3N4 composites have an improved photocatalytic performance for decomposing organic pollutants compared with that of pure g-C3N4 nanosheets. Many measurements have been used for characterizing the samples, such as XRD, FTIR, UV-Vis DRS, PL, XPS, EDS, SEM, and TEM. In Ag/g-C3N4, the Ag NPs are uniformly coated on the g-C3N4 surface, the diameter is mainly in the range of 8~18 nanometers. Loading of Ag NPs expand the response to the visible light for g-C3N4 and increasing the producing rate of photogenerated e--h+ pairs. The loading of silver NPs obviously enhances the photocatalytic activity of C3N4 nanosheets toward the Rhodamine B (RhB) decomposition under the simulated sunlight irradiation. With different loading amounts of Ag NPs, Ag/g-C3N4 (3 wt% of Ag) showed the highest photocatalytic activity for RhB decomposition among these as-prepared samples, which is 10 times of the rate of pure C3N4. Based on the experimental results, a possible photocatalytic mechanism for Ag/g-C3N4 is proposed.

19.
Dalton Trans ; 48(9): 3038-3044, 2019 Feb 26.
Article in English | MEDLINE | ID: mdl-30758024

ABSTRACT

A photo-Fenton-like reaction was considered as an effective method for wastewater treatment because it could produce more oxidative species such as hydroxyl radicals (˙OH) to accelerate the reaction. In this paper, a NiFe2O4/C (abbr. as NFO/C) yolk-shell nanostructure was synthesized via one-step calcination using polyacrylic acid sodium salt (PAAS) NPs as a template. The nanocomposite was characterized using X-ray diffraction (XRD), field-emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption-desorption, among others. The magnetically separable nanocomposite exhibited a high activity and recyclability towards the photodegradation of tetracycline hydrochloride (TC). In addition, the factors affecting the photodegradation process were systematically investigated, including the dosage of the NiFe2O4/C catalyst, the pH of the solution, and the volume of H2O2. Notably, the degradation rate of tetracycline hydrochloride (TC) reached 97.25% in 60 min in the presence of H2O2 under visible light irradiation (λ > 400 nm) with NiFe2O4/C. This work provides a simple and novel method to construct NiFe2O4/C yolk-shell nanostructures, which may be applied to the photodegradation of tetracycline hydrochloride from wastewater. Finally, a photocatalytic and stability mechanism is proposed, which may help us more comprehensively understand the photo-Fenton mechanism.

20.
Front Chem ; 7: 941, 2019.
Article in English | MEDLINE | ID: mdl-32133336

ABSTRACT

Energy crises and environmental pollution are two serious threats to modern society. To overcome these problems, graphitic carbon nitride (g-C3N4) nanosheets were fabricated and functionalized with SnO2 nanoparticles to produce H2 from water splitting and degrade 2-chlorophenol under visible light irradiation. The fabricated samples showed enhanced photocatalytic activities for both H2 evolution and pollutant degradation as compared to bare g-C3N4 and SnO2. These enhanced photoactivities are attributed to the fast charge separation as the excited electrons transfer from g-C3N4 to the conduction band of SnO2. This enhanced charge separation has been confirmed by the photoluminescence spectra, steady state surface photovoltage spectroscopic measurement, and formed hydroxyl radicals. It is believed that this work will provide a feasible route to synthesize photocatalysts for improved energy production and environmental purification.

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