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1.
J Adhes Dent ; 26(1): 147-170, 2024 Jan 15.
Article in English | MEDLINE | ID: mdl-38785223

ABSTRACT

PURPOSE: To systematically review in-vitro studies that evaluated the influence of erbium laser pretreatment on dentin shear bond strength (SBS) and bond failure modes. MATERIALS AND METHODS: Electronic databases (PubMed, Cochrane Central, Embase, and Web of Science) were searched. Only in-vitro studies involving erbium laser irradiation of the dentin surface and SBS testing of the bonded resin block were included. The three common modes of bond failure (1. adhesive, 2. cohesive, and 3. mixed) were observed and analyzed. The network meta-analysis (NMA) was performed by Stata 15.0 software, the risk of bias was evaluated, and the certainty of the evidence was assessed by the Confidence in Network Meta-analysis (CINeMA). RESULTS: Forty studies with nine pretreatments (1. blank group: BL; 2. phosphoric acid etch-and-rinse: ER; 3. self-etch adhesive: SE; 4. Er:YAG laser: EL; 5. Er,Cr:YSGG laser: ECL; 6. ER+EL; 7. ER+ECL; 8. SE+EL; 9. SE+ECL) were included in this analysis. The NMA of SBS showed that ER+EL [SMD = 0.32, 95% CI (0.11, 0.98)] had the highest SBS next to ER, especially when using one of the 3M ESPE adhesives, followed by EL, ECL, SE and SE+EL. The Ivoclar Vivadent adhesives significantly increased the SBS of the ECL [SMD = 0.37, 95% CI (0.16,0.90)] and was higher than ER+EL [SMD = 0.25,95% CI (0.07,0.85)]. Finally, the surface under the cumulative ranking curve (SUCRA) value indicated that ER+EL (SUCRA = 71.0%) and EL (SUCRA = 62.9%) were the best treatments for enhancing dentin SBS besides ER. ER+EL (SUCRA = 85.3%), ER (SUCRA = 83.7%) and ER (SUCRA = 84.3%) had the highest probability of occurring in adhesive, cohesive and mixed failure modes, respectively. CONCLUSION: Er:YAG and Er,Cr:YSGG lasers improved dentin SBS compared to the blank group, especially when the acid etch-and-rinse pretreatment was combined with Er:YAG laser. Shear bond strength and failure mode do not appear to be directly related.


Subject(s)
Dental Bonding , Dentin , Lasers, Solid-State , Shear Strength , Dental Bonding/methods , Lasers, Solid-State/therapeutic use , Humans , Network Meta-Analysis , Dentin-Bonding Agents/chemistry , Acid Etching, Dental , Dental Stress Analysis
2.
J Dent ; 146: 105026, 2024 07.
Article in English | MEDLINE | ID: mdl-38679134

ABSTRACT

OBJECTIVES: To analyze the role of oxidative stress (OS) biomarkers in peri­implant diseases using a systematic review and meta-analysis approach. DATE: The review incorporated cross-sectional studies, randomized controlled trials, and case-control trials to evaluate the differences in OS biomarkers of peri­implant disease. SOURCES: A comprehensive literature search was conducted in electronic databases such as PubMed, Scopus, Embase, Web of Science, and CNKI, and no restrictions were applied during the search process. STUDY SELECTION: A total of 452 studies were identified, of which 18 were eligible for inclusion. Risk of bias and sensitivity analysis were assessed using Egger's test and funnel plots. RESULTS: We found that the levels of glutathione peroxidase (GSH-Px) in the peri­implant sulcus fluid (PISF) of patients with peri­implant diseases were significantly reduced (SMD = -1.40; 95 % CI = 1.70, -1.11; p < 0.001), while the levels of total myeloperoxidase (MPO) and malondialdehyde (MDA) were significantly increased (SMD = 0.46; 95 % CI = 0.12, 0.80; p = 0.008; SMD = 0.28; 95 % CI = 0.01, 0.56; p = 0.043). However, there were no significant differences of MPO concentration (SMD = 0.38; 95 % CI = -0.39, 1.15; p = 0.331) and superoxide dismutase (SOD)(SMD = -0.43; 95 % CI = -1.94, 1.07; p = 0.572) in PISF between peri­implant disease group and control group. Similarly, salivary MPO did not show significant differences (SMD = 1.62; 95 % CI = -1.01, 4.24; p = 0.227). CONCLUSIONS: Our results supported that the level of local OS biomarkers was closely related to peri­implant diseases. GSH-Px, total MPO and MDA may be PISF biomarkers with good capability to monitor the development of peri­implant disease. CLINICAL SIGNIFICANCE: This study found significant differences in the levels of local OS biomarkers (GSH-Px, total MPO, and MDA) between patients with peri­implant diseases and healthy subjects, which may be ideal candidate biomarkers for predicting and diagnosing peri­implant diseases.


Subject(s)
Biomarkers , Dental Implants , Glutathione Peroxidase , Malondialdehyde , Oxidative Stress , Peri-Implantitis , Peroxidase , Humans , Biomarkers/analysis , Peroxidase/analysis , Malondialdehyde/analysis , Malondialdehyde/metabolism , Peri-Implantitis/metabolism , Glutathione Peroxidase/analysis , Glutathione Peroxidase/metabolism , Gingival Crevicular Fluid/chemistry
3.
BMC Oral Health ; 23(1): 980, 2023 12 08.
Article in English | MEDLINE | ID: mdl-38066540

ABSTRACT

BACKGROUND: Apical periodontitis directly affects the stress state of the affected tooth owing to the destruction of the periapical bone. Understanding the mechanical of periapical bone defects/tooth is clinically meaningful. In this study, we evaluate the effect of periapical bone defects on the stress distribution in teeth with periapical periodontitis using finite element analysis. METHODS: Finite element models of normal mandibular second premolars and those with periapical bone defects (spherical defects with diameters of 5, 10, 15, and 20 mm) were created using a digital model design software. The edges of the mandible were fixed and the masticatory cycle was simplified as oblique loading (a 400 N force loaded obliquely at 45° to the long axis of the tooth body) to simulate the tooth stress state in occlusion and analyze the von Mises stress distribution and tooth displacement distribution in each model. RESULTS: Overall analysis of the models: Compared to that in the normal model, the maximum von Mises stresses in all the different periapical bone defect size models were slightly lower. In contrast, the maximum tooth displacement in the periapical bone defect model increased as the size of the periapical bone defect increased (2.11-120.1% of increase). Internal analysis of tooth: As the size of the periapical bone defect increased, the maximum von Mises stress in the coronal cervix of the tooth gradually increased (2.23-37.22% of increase). while the von Mises stress in the root apical region of the tooth showed a decreasing trend (41.48-99.70% of decrease). The maximum tooth displacement in all parts of the tooth showed an increasing trend as the size of the periapical bone defect increased. CONCLUSIONS: The presence of periapical bone defects was found to significantly affect the biomechanical response of the tooth, the effects of which became more pronounced as the size of the bone defect increased.


Subject(s)
Periapical Periodontitis , Software , Humans , Finite Element Analysis , Stress, Mechanical , Bicuspid , Dental Stress Analysis
4.
BMC Oral Health ; 23(1): 973, 2023 12 06.
Article in English | MEDLINE | ID: mdl-38057755

ABSTRACT

AIM: To evaluate the effects of root canal treatment (RCT) and post-crown restoration on stress distribution in teeth with periapical bone defects using finite element analysis. METHODOLOGY: Finite element models of mandibular second premolars and those with periapical bone defects (spherical defects with diameters of 5, 10, 15, and 20 mm) were created using digital model design software. The corresponding RCT and post-crown restoration models were constructed based on the different sizes of periapical bone defect models. The von Mises stress and tooth displacement distributions were comprehensively analyzed in each model. RESULTS: Overall analysis of the models: RCT significantly increased the maximum von Mises stresses in teeth with periapical bone defects, while post-crown restoration greatly reduced the maximum von Mises stresses. RCT and post-crown restoration slightly reduced tooth displacement in the affected tooth. Internal analysis of tooth: RCT dramatically increased the maximum von Mises stress in all regions of the tooth, with the most pronounced increase in the coronal surface region. The post-crown restoration balances the internal stresses of the tooth and is most effective in periapical bone defect - 20-mm model. RCT and post-crown restoration slightly reduced the tooth displacement in all regions of the affected tooth. CONCLUSIONS: Root canal treatment seemed not to improve the biomechanical state of teeth with periapical bone defects. In contrast, post-crown restoration might effectively balance the stress concentrations caused by periapical bone defects, particularly extensive ones.


Subject(s)
Periapical Periodontitis , Tooth Crown , Humans , Finite Element Analysis , Dental Pulp Cavity , Crowns , Periapical Periodontitis/therapy
5.
J Am Chem Soc ; 145(46): 25431-25439, 2023 Nov 22.
Article in English | MEDLINE | ID: mdl-37955662

ABSTRACT

Reversible Pickering emulsions, achieved by switchable, interfacially active colloidal particles, that enable on-demand emulsification/demulsification or phase inversion, hold substantial promise for biphasic catalysis, emulsion polymerization, cutting fluids, and crude oil pipeline transportation. However, particles with such a responsive behavior usually require complex chemical syntheses and surface modifications, limiting their extensive use. Herein, we report a simple route to generate emulsions that can be controlled and reversibly undergo phase inversion. The emulsions are prepared and stabilized by the interfacial assembly of polyoxometalate (POM)-polymer, where their electrostatic interaction at the interface is dynamic. The wettability of the POMs that dictates the emulsion type can be readily regulated by tuning the number of polymer chains bound to POMs, which, in turn, can be controlled by varying the concentrations of both components and the water/oil ratio. In addition, the number of polymer chains anchored to the POMs can be varied by controlling the number of negative charges on the POMs through an in situ redox reaction. As such, a reversible inversion of the emulsions can be triggered by switching between exposure to ultraviolet light and the introduction of oxygen. Combining the functions of POM itself, a cyclic interfacial catalysis system was realized. Inversion of the emulsion also affords a pathway to high-internal-phase emulsions. The diversity of the POMs, the polymers, and the responsive switching groups open numerous new, simple strategies for designing a wide range of responsive soft matter for cargo loading, controlled release, and delivery in biomedical and engineering applications without time-consuming particle syntheses.

6.
J Am Chem Soc ; 145(43): 23651-23658, 2023 Nov 01.
Article in English | MEDLINE | ID: mdl-37859406

ABSTRACT

Defects in metal-organic frameworks (MOFs) can significantly change their local microstructures, thus notably leading to an alteration-induced performance in sorption or catalysis. However, achieving de novo defect engineering in MOFs under ambient conditions without the scarification of their crystallinity remains a challenge. Herein, we successfully synthesize defective ZIF-7 through 60Co gamma ray radiation under ambient conditions. The obtained ZIF-7 is defect-rich but also has excellent crystallinity, enhanced BET surface area, and hierarchical pore structure. Moreover, the amount and structure of these defects within ZIF-7 were determined from the two-dimensional (2D) 13C-1H frequency-switched Lee-Goldburg heteronuclear correlation (FSLG-HETCOR) spectra, continuous rotation electron diffraction (cRED), and high-resolution transmission electron microscopy (HRTEM). Interestingly, the defects in ZIF-7 all strongly bind to CO2, leading to a remarkable enhancement of the CO2 sorption capability compared with that synthesized by the solvothermal method.

7.
Environ Int ; 172: 107768, 2023 02.
Article in English | MEDLINE | ID: mdl-36709675

ABSTRACT

The global livestock system is one of the largest sources of ammonia emissions and there is an urgent need for ammonia mitigation. Here, we designed and constructed a novel strategy to abate ammonia emissions via livestock manure acidification based on a synthetic lactic acid bacteria community (LAB SynCom). The LAB SynCom possessed a wide carbon source spectrum and pH profile, high adaptability to the manure environment, and a high capability of generating lactic acid. The mitigation strategy was optimized based on the test and performance by adjusting the LAB SynCom inoculation ratio and the adding frequency of carbon source, which contributed to a total ammonia reduction efficiency of 95.5 %. Furthermore, 16S rDNA amplicon sequencing analysis revealed that the LAB SynCom treatment reshaped the manure microbial community structure. Importantly, 22 manure ureolytic microbial genera and urea hydrolysis were notably inhibited by the LAB SynCom treatment during the treatment process. These findings provide new insight into manure acidification that the conversion from ammonia to ammonium ions and the inhibition of ureolytic bacteria exerted a synergistic effect on ammonia mitigation. This work systematically developed a novel strategy to mitigate ammonia emissions from livestock waste, which is a crucial step forward from traditional manure acidification to novel and environmental-friendly acidification.


Subject(s)
Ammonia , Manure , Animals , Ammonia/analysis , Livestock , Bacteria , Carbon , Hydrogen-Ion Concentration
8.
Front Oncol ; 12: 874473, 2022.
Article in English | MEDLINE | ID: mdl-35530353

ABSTRACT

Purpose: To compare the efficacy and safety of the combination of transcatheter arterial chemoembolization (TACE), Lenvatinib, and programmed cell death protein-1 (PD-1) inhibitors (combination group) with TACE (TACE group) in the treatment of patients with unresectable hepatocellular carcinoma (uHCC). Methods: We consecutively enrolled 110 patients with uHCC in this prospective cohort study, with 56 patients receiving combination treatment and 54 patients receiving TACE from November 2017 to September 2020. The differences in tumor response, survival benefit, and adverse events (AEs) were compared between the two groups. Factors affecting survival were identified via Cox regression analysis. Results: Compared with the TACE group, the combination group had a higher objective response rate (ORR) (67.9% vs. 29.6%, p < 0.001), longer median progression-free survival (mPFS) (11.9 vs. 6.9 months, P = 0.003) and overall survival (mOS) (23.9 vs. 15.3 months, p < 0.001). Multivariate analysis showed that the neutrophil-to-lymphocyte ratio (NLR) and the treatment option were independent factors associated with the PFS and OS. Further subgroup analysis showed that patients with low NLR (≤median 3.11) receiving combination therapy had better mPFS (20.1 vs. 6.2 months, P < 0.001) and mOS (28.9 vs. 15.2 months, P < 0.001) than those receiving TACE, while no obvious difference in PFS or OS was observed between the two groups in patients with high NLR (> 3.11). There were no unexpected toxicities in the combination group. Conclusion: Compared with TACE, the combination treatment demonstrated an improved clinical efficacy and manageable safety profile in patients with uHCC. Combination treatment showed better therapeutic efficacy in patients with low NLR; therefore, this ratio could be used to identify patients who will benefit from this treatment.

9.
Macromol Rapid Commun ; 43(18): e2200193, 2022 Sep.
Article in English | MEDLINE | ID: mdl-35622941

ABSTRACT

Emulsion as a fine dispersion of immiscible liquids has involved widespread applications in industry, pharmaceuticals, agriculture, and personal care. Stimuli-responsive emulsions capable of on-demand demulsification or changing their properties are required in many cases such as controllable release cargo, oil recovery, emulsifier recycling, and product separation, great progress is achieved in these areas. Among these various triggers, much effort is made to develop physical stimuli, due to the noninvasive and environmentally friendly characteristics. Physical stimuli-responsive emulsions provide plenty of valuable practical applications in the fields of sustainable industry, biomedical reaction, drug delivery. Here, the recent development in the field of emulsions in response to physical stimuli consisting of temperature, light, magnetic fields, electrical fields, etc., is summarized. The preparation methods and mechanisms of physical stimuli-responsive emulsions and their applications of catalysis reaction, drug delivery, and oil recovery are highlighted in this review. The future directions and outstanding problems of the physical stimuli-responsive emulsions are also discussed.


Subject(s)
Drug Delivery Systems , Emulsions , Temperature
10.
Se Pu ; 40(6): 565-575, 2022 Jun.
Article in Chinese | MEDLINE | ID: mdl-35616202

ABSTRACT

A rapid screening method for 84 pesticide residues in dendrobium perfringens parent material with different polarities was developed using a Sin-QuEChERS Nano clean-up column combined with gas chromatography-tandem mass spectrometry (GC-MS/MS). The differences in extraction efficiency of the targets were compared with different extraction solvents (acetonitrile containing 1% acetic acid, acetone) and methods (immersion with or without water). The purification effect and extraction recoveries of Sin-QuEChERS Nano method and classical dispersive solid-phase extraction (dSPE), solid-phase extraction (SPE) and QuEChERS were systematically compared using Dendrobium nobile samples. The differences in matrix effects between the Sin-QuEChERS Nano method, which was more effective in purification, and the dSPE method were also analyzed. The purification effects of three commercially available Sin-QuEChERS Nano purification columns (simple matrix purification column, complex matrix purification column and herbal purification column) were compared. The applicability of the purification methods were also verified by using different parts of Dendrobium nobile samples (stems, leaves and flowers). From the results, it could be concluded that weighing 2.00 g and the samples in 5 mL of water for 20 min, followed by extraction with acetonitrile containing 1% acetic acid was more effective. The average extraction recovery of the target components by Sin-QuEChERS Nano purification method was 90.5%, which further identified Sin-QuEChERS Nano-Chinese medicine purification column as the preferred purification column for dendrobium purification. The target components were separated by a DB-1701MS quartz capillary column (30 m×0.25 mm×0.25 µm) with programmed temperature rise, detected by multiple reaction monitoring (MRM) mode, and quantified by matrix-matched solution external standard method. The GC-MS/MS assay was used for the methodological validation of the 84 representative pesticides within Dendrobium officinale and Dendrobium nobile was carried out by GC-MS/MS detection method. The results indicated that the targets showed excellent linear correlation in different scopes with correlation coefficients (r2) >0. 990. The limits of detection (LODs, S/N=3) of the method were 1.5 to 5.8 µg/kg, and the limits of quantification (LOQs, S/N=10) ranged from 5.0 to 15.0 µg/kg. The spiked recoveries of the target pesticides under different spiked levels were 68.7%-116.2%, and the relative standard deviations (RSDs, n=6) were less than 15%. Compared to other typical pretreatment methods, the Sin-QuEChERS Nano method provided better performance in terms of purification. The method not only effectively removed pigments, organic acids, and alkaline interferents, but also saved preparation time. Losses due to solvent transfer were also avoided and no further vortexing or centrifugation was required, making it a simplified and effective extraction and purification procedure. The method was sensitive, rapid, simple and reliable. It effectively improved the detection efficiency during the rapid screening of pesticides in dendrobium and presented a strong practical application value. In addition, the developed method could further expand the types of target pesticides and could be used to detect more pesticide residues in foods and Chinese herbal medicine. The established Sin-QuEChERS Nano method was used for the analysis of authentic samples. The applicability of the method was evaluated by analyzing a total of 80 samples collected from Anlong, Libo, Dushan, and Yanhe County in Guizhou Province. The types of samples included dendrobium maple, Dendrobium nobile (flowers, stems, leaves) and Dendrobium officinale (flowers, stems, leaves, powder, tablets). At least one pesticide residue was detected in 12 samples, with a detection rate of 15%. The five pesticides with higher detection rates and residues were chlorpyrifos (0.08-0.5 mg/kg), chlorothalonil (0.06-3.2 mg/kg), propanil zinc (0.03-0.15 mg/kg), methyl parathion (0.04-0.23 mg/kg) and cyhalothrin (0.10-2.68 mg/kg). Except for the pesticides in maximum residue limits (MRLs), the pesticide residues detected from dendrobium samples were below the limits set by Chinese national standard (GB 2763-2021) and local standard DBS 52/048-2020.


Subject(s)
Dendrobium , Pesticide Residues , Pesticides , Acetonitriles/analysis , Gas Chromatography-Mass Spectrometry , Pesticide Residues/analysis , Pesticides/analysis , Solid Phase Extraction , Solvents/analysis , Tandem Mass Spectrometry , Water/analysis
11.
ACS Appl Mater Interfaces ; 14(2): 3057-3065, 2022 Jan 19.
Article in English | MEDLINE | ID: mdl-34985852

ABSTRACT

Modulation of the microstructure and configurational entropy tuning are the core stratagem for improving thermoelectric performance. However, the correlation of evolution among the preparation methods, chemical composition, structural defects, configurational entropy, and thermoelectric properties is still unclear. Herein, two series of AgSbTe2-based compounds were synthesized by an equilibrium melting-slow-cooling method and a nonequilibrium melting-quenching-spark plasma sintering (SPS) method, respectively. The equilibrium method results in coarse grains with a size of >300 µm in the samples and a lower defect concentration, leading to higher carrier mobility of 10.66 cm2 V-1 s-1 for (Ag2Te)0.41(Sb2Te3)0.59 compared to the sample synthesized by nonequilibrium preparation of 1.83 cm2 V-1 s-1. Moreover, tuning the chemical composition of nonstoichiometric AgSbTe2 effectively improves the configurational entropy and creates a large number of cation vacancies, which evolve into dense dislocations in the samples. Owing to all of these in conjunction with the strong inharmonic vibration of lattice, an ultralow thermal conductivity of 0.51 W m-1 K-1 at room temperature is achieved for the (Ag2Te)0.42(Sb2Te3)0.58 sample synthesized by the equilibrium preparation method. Due to the enhanced carrier mobility, optimized carrier concentration, and low thermal conductivity, the (Ag2Te)0.42(Sb2Te3)0.58 sample synthesized by the equilibrium preparation method possesses the highest ZT of 1.04 at 500 K, more than 60% higher than 0.64 at 500 K of the same composition synthesized by nonequilibrium preparation.

12.
ACS Appl Mater Interfaces ; 13(50): 60216-60226, 2021 Dec 22.
Article in English | MEDLINE | ID: mdl-34874703

ABSTRACT

Bismuth telluride-based alloys are the best performing thermoelectric materials near room temperature. Grain size refinement and nanostructuring are the core stratagems for improving thermoelectric and mechanical properties. However, the donor-like effect induced by grain size refinement strongly restricts the thermoelectric properties especially in the vicinity of room temperature. In this study, the formation mechanism for the donor-like effect in Bi2Te3-based compounds was revealed by synthesizing five batches of polycrystalline samples. We demonstrate that the donor-like effect in Bi2Te3-based compounds is strongly related to the vacancy defects (VBi‴ and VTe···) induced by the fracturing process and oxygen in air for the first time. The oxygen-induced donor-like effect dramatically increases the carrier concentration from 2.5 × 1019 cm-3 for the zone melting ingot and bulks sintered with powders ground under an inert atmosphere to 7.5 × 1019 cm-3, which is largely beyond the optimum carrier concentration and seriously deteriorates the thermoelectric performance. Moreover, it is found that both avoiding exposure to air and eliminating the thermal vacancy defects (VBi‴ and VTe···) via heat treatment before exposure to air can effectively remove the donor-like effect, producing almost the same carrier concentration and Seebeck coefficient as those of the zone melting ingot for these samples. Therefore, a defect equation of oxygen-induced donor-like effect was proposed and was further explicitly corroborated by positron annihilation measurement. With the removal of donor-like effect and improved texturing via multiple hot deformation (HD) processes, a maximum power factor of 3.5 mW m-1 K-2 and a reproducible maximum ZT value of 1.01 near room temperature are achieved. This newly proposed defect equation of the oxygen-induced donor-like effect will provide a guideline for developing higher-performance V2VI3 polycrystalline materials for near-room-temperature applications.

13.
Sci Adv ; 7(31)2021 Jul.
Article in English | MEDLINE | ID: mdl-34330704

ABSTRACT

Arctic sea ice extent in autumn is significantly correlated with the winter North Atlantic Oscillation (NAO) in the satellite era. However, questions about the robustness and reproducibility of the relationship persist. Here, we show that climate models are able to simulate periods of strong ice-NAO correlation, albeit rarely. Furthermore, we show that the winter circulation signals during these periods are consistent with observations and not driven by sea ice. We do so by interrogating a multimodel ensemble for the specific time scale of interest, thereby illuminating the dynamics that produce large spread in the ice-NAO relationship. Our results support the importance of internal variability over sea ice but go further in showing that the mechanism behind strong ice-NAO correlations, when they occur, is similar in longer observational records and models. Rather than sea ice, circulation anomalies over the Urals emerge as a decisive precursor to the winter NAO signal.

14.
ACS Appl Mater Interfaces ; 13(3): 4185-4191, 2021 Jan 27.
Article in English | MEDLINE | ID: mdl-33433997

ABSTRACT

AgBi3S5 is an environmentally friendly n-type thermoelectric material composed of earth-abundant and nontoxic elements. It has a complex monoclinic structure with distorted NaCl-type fragments, which provide its intrinsically low thermal conductivity. However, poor electrical properties limit its overall performance. Configurational entropy engineering is an effective method to enhance thermoelectric properties. With the increase of configurational entropy, phonon point defect scattering is amplified, yielding lower lattice thermal conductivity, while the structure symmetry can also be improved, which leads to the enhanced electrical transport property. In this study, we combine carrier modulation and entropy engineering, utilizing melting-annealing and spark plasma sintering, to synthesize a series of AgBi3(SeyS1-y)5.08 bulks. Se substitution effectively increases the configurational entropy and thus dramatically decreases the thermal conductivity. Moreover, anion deficiency modulation effectively optimizes the carrier concentration and the electrical transport properties. Due to a power factor of 2.7 µW/(cm·K2) and a low thermal conductivity of 0.45 W/(m·K) at 723 K, the AgBi3(Se0.9S0.1)5.08 sample possesses the highest ZT of 0.42 at 723 K, nearly double the value of AgBi3S5.08 or pristine AgBi3S5. Our work demonstrates that apart from carrier optimization, entropy engineering opens a new avenue for enhancing the thermoelectric properties of a given material.

15.
Adv Mater ; 32(23): e2000063, 2020 Jun.
Article in English | MEDLINE | ID: mdl-32363687

ABSTRACT

Precise control of the microstructure in organic semiconductors (OSCs) is essential for developing high-performance organic electronic devices. Here, a comprehensive charge transport characterization of two recently reported rigid-rod conjugated polymers that do not contain single bonds in the main chain is reported. It is demonstrated that the molecular design of the polymer makes it possible to achieve an extended linear backbone structure, which can be directly visualized by high-resolution scanning tunneling microscopy (STM). The rigid structure of the polymers allows the formation of thin films with uniaxially aligned polymer chains by using a simple one-step solution-shear/bar coating technique. These aligned films show a high optical anisotropy with a dichroic ratio of up to a factor of 6. Transport measurements performed using top-gate bottom-contact field-effect transistors exhibit a high saturation electron mobility of 0.2 cm2 V-1 s-1 along the alignment direction, which is more than six times higher than the value reported in the previous work. This work demonstrates that this new class of polymers is able to achieve mobility values comparable to state-of-the-art n-type polymers and identifies an effective processing strategy for this class of rigid-rod polymer system to optimize their charge transport properties.

16.
Zhonghua Wei Zhong Bing Ji Jiu Yi Xue ; 31(10): 1304-1306, 2019 Oct.
Article in Chinese | MEDLINE | ID: mdl-31771735

ABSTRACT

OBJECTIVE: Heat stroke is the most serious type of heat-related diseases, and the induced multiple organ dysfunction syndrome (MODS) is an important cause of death for heat stroke patients. The cardiovascular system is one of the important targets of heat injury. Studies have reported that heat stress can lead to myocardial inhibition, abnormal heart conduction and blood flow redistribution, thus changing the hemodynamic state, leading to obvious abnormalities in electrocardiogram, echocardiography, myocardial injury biological markers and hemodynamic indicators of patients with heat stroke. In this article, the pathophysiological and histological changes and clinical manifestations of heatstroke-induced myocardial injury are reviewed, aiming to provide references for further understanding and research of myocardial damage caused by hyperthermia.


Subject(s)
Heart Injuries , Heat Stroke , Biomarkers , Heart Rate , Humans , Multiple Organ Failure
17.
Zhonghua Wei Zhong Bing Ji Jiu Yi Xue ; 30(10): 1006-1010, 2018 Oct.
Article in Chinese | MEDLINE | ID: mdl-30439327

ABSTRACT

OBJECTIVE: Heat stroke (HS) is a life-threatening illness characterized by an altered level of consciousness with an elevated core body temperature 40 centigrade, which may be further classified as exertional heat stroke (EHS) or classical heat stroke (CHS) according to the etiology of the condition. In recent years, the morbidity of EHS increases year by year. The severity and clinical outcome for an EHS casualty have a strong correlation with the area under the time and temperature curve for heat exposure. The early recognition and rapid cooling body core temperature ≤ 38.9 centigrade within 30 minutes of EHS results in the best clinical outcome and minimize severe multiple organ dysfunction and death for patients. Cold water immersion (CWI) is considered as an optimum cooling method for the reversal of hyperthermia in EHS. Some alternative modalities have also shown acceptable cooling rate, for example, the subjects immersed in a circulated water bath controlled below 20 centigrade, tarp-assisted cooling with oscillation, body cooling unit, undressed, air-conditioned room, the whole body and large vessels placed ice packs, massaging the extremities; cold intravenous saline applied to dehydrated one. It is necessary to monitor body core temperature for hypothermia and/or recurrent hyperthermia, and to provide physical care for shivering, agitation, or concerns with the potential discomfort combativeness that may occur during cooling process. In this paper, pre-hospital recognition, care, monitoring and rapid cooling treatment measures of EHS have been reviewed to provide references for early identification of EHS and scientific, reasonable and effective cooling treatment.


Subject(s)
Emergency Medical Services , Heat Stroke/diagnosis , Heat Stroke/therapy , Hypothermia, Induced , Humans
18.
Sci Adv ; 4(7): eaat6025, 2018 07.
Article in English | MEDLINE | ID: mdl-30050990

ABSTRACT

Previous studies have extensively investigated the impact of Arctic sea ice anomalies on the midlatitude circulation and associated surface climate in winter. However, there is an ongoing scientific debate regarding whether and how sea ice retreat results in the observed cold anomaly over the adjacent continents. We present a robust "cold Siberia" pattern in the winter following sea ice loss over the Barents-Kara seas in late autumn in an advanced atmospheric general circulation model, with a well-resolved stratosphere. Additional targeted experiments reveal that the stratospheric response to sea ice forcing is crucial in the development of cold conditions over Siberia, indicating the dominant role of the stratospheric pathway compared with the direct response within the troposphere. In particular, the downward influence of the stratospheric circulation anomaly significantly intensifies the ridge near the Ural Mountains and the trough over East Asia. The persistently intensified ridge and trough favor more frequent cold air outbreaks and colder winters over Siberia. This finding has important implications for improving seasonal climate prediction of midlatitude cold events. The results also suggest that the model performance in representing the stratosphere-troposphere coupling could be an important source of the discrepancy between recent studies.

19.
J Geophys Res Atmos ; 123(20): 11377-11391, 2018 Oct 27.
Article in English | MEDLINE | ID: mdl-32745154

ABSTRACT

Previous observational studies have found a persistent maximum in stratospheric water vapor (SWV) in the upper troposphere lower stratosphere (UTLS) confined by the upper-level anticyclone over the Asian summer monsoon region. This study investigates the simulation of SWV in the Whole Atmosphere Community Climate Model (WACCM). WACCM generally tends to simulate a SWV maximum over the central Pacific Ocean, but this bias is largely improved in the high vertical resolution version. The high vertical resolution model with increased vertical layers in the UTLS is found to have a less stratified UTLS over the central Pacific Ocean compared with the low vertical resolution model. It therefore simulates a steepened PV gradient over the central Pacific Ocean that better closes the upper-level anticyclone and confines the SWV within the enhanced transport barrier.

20.
Org Biomol Chem ; 15(40): 8627-8633, 2017 Oct 18.
Article in English | MEDLINE | ID: mdl-28980697

ABSTRACT

A tripodal fluorescent probe L1 armed with Rhodamine B and 1-naphthaleneisothiocyanates was prepared in high yield. A study of the recognition properties revealed that probe L1 exhibited high sensitivity and selectivity towards Al3+ through a "FRET" fluorescence response and colorimetric response with low detection limits of the order of 10-8 M. Meanwhile, probe L1 also possessed high recognition ability for I- through fluorescence decay, which given there are comparatively few selective fluorescent probes for I-, is significant. Furthermore, the complexation mechanisms were fully investigated by spectral titrations, 1H NMR spectroscopic titrations and mass spectrometry. The utility of probe L1 as a biosensor in living cells (PC3 cells) towards Al3+ ions has also been demonstrated.

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