Your browser doesn't support javascript.
loading
: 20 | 50 | 100
1 - 20 de 28
1.
Eur J Radiol Open ; 12: 100564, 2024 Jun.
Article En | MEDLINE | ID: mdl-38681662

Background: Respiratory-triggered (RT) and breath-hold are the most common acquisition modalities for magnetic resonance cholangiopancreatography (MRCP). The present study compared the three different acquisition modalities for optimizing the use of MRCP in patients with diseases of the pancreatic and biliary systems. Materials and methods: Three MRCP acquisition modalities were used in this study: conventional respiratory-triggered sampling perfection with application-optimized contrasts using different flip evolutions (RT-SPACE), modified RT-SPACE, and breath-hold (BH)-SPACE. Fifty-eight patients with clinically suspected pancreatic and biliary system disease were included. All image data were acquired on a 1.5 T MR. Scan time and image quality were compared between the three acquisition modalities. Friedman test, which was followed by post-hoc analysis, was performed among triple-scan protocol. Results: There was a significant difference in the mean acquisition time among conventional RT-SPACE, modified RT-SPACE, and BH-SPACE (167.41±32.11 seconds vs 50.84±73.78 seconds vs 18.00 seconds, P <0.001). Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were also significantly different among the three groups (P <0.001). The SNR and CNR were higher in the RT-SPACE group than in the BH-SPACE group (P <0.05). However, there were no statistically significant differences (P >0.05) among the 3 groups regarding quality of overall image, image clarity, background inhibition, and visualization of the pancreatic and biliary system. Conclusions: MRCP acquisition with the modified RT-SPACE sequence greatly shortens the acquisition time with comparable quality images. The MRCP acquisition modality could be designed based on the patient's situation to improve the examination pass rate and obtain excellent images for diagnosis.

2.
Nat Nanotechnol ; 2024 Apr 22.
Article En | MEDLINE | ID: mdl-38649746

Nanoresolved doping of polymeric semiconductors can overcome scaling limitations to create highly integrated flexible electronics, but remains a fundamental challenge due to isotropic diffusion of the dopants. Here we report a general methodology for achieving nanoscale ion-implantation-like electrochemical doping of polymeric semiconductors. This approach involves confining counterion electromigration within a glassy electrolyte composed of room-temperature ionic liquids and high-glass-transition-temperature insulating polymers. By precisely adjusting the electrolyte glass transition temperature (Tg) and the operating temperature (T), we create a highly localized electric field distribution and achieve anisotropic ion migration that is nearly vertical to the nanotip electrodes. The confined doping produces an excellent resolution of 56 nm with a lateral-extended doping length down to as little as 9.3 nm. We reveal a universal exponential dependence of the doping resolution on the temperature difference (Tg - T) that can be used to depict the doping resolution for almost infinite polymeric semiconductors. Moreover, we demonstrate its implications in a range of polymer electronic devices, including a 200% performance-enhanced organic transistor and a lateral p-n diode with seamless junction widths of <100 nm. Combined with a further demonstration in the scalability of the nanoscale doping, this concept may open up new opportunities for polymer-based nanoelectronics.

3.
Front Public Health ; 12: 1310383, 2024.
Article En | MEDLINE | ID: mdl-38375338

Objective: This review aimed to analyze and compare the accuracy of eight screening tools for sarcopenia in older Chinese adults according to different diagnostic criteria. Methods: This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The PubMed, Embase, Web of Science, China National Knowledge Infrastructure (CNKI), and Wanfang databases were searched between the publication of the first expert consensus on sarcopenia in 2010 and April 2023 using relevant MeSH terms. We evaluated the risk bias of the included studies using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool. The pooled result of sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and plot the summary receiver operating characteristic curve (SROC) were calculated by using a bivariate random-effects model. The accuracies of sensitivity and specificity of the screening tools were compared using the Z-test. Results: A total of 30 studies (23,193 participants) were included, except for calf circumference (CC), Ishii, and Finger-ring Test; Screening tools for sarcopenia in older Chinese adults have consistently shown low to moderate sensitivity and moderate to high specificity. Regional and sex differences affect the accuracy of the screening tools. In terms of sensitivity and specificity, the CC, Ishii, and Finger-ring Test were superior to the other screening tools. Conclusion: The Asian Working Group on Sarcopenia (AWGS) 2019 criteria are more appropriate for the diagnosis of sarcopenia in older Chinese adults. According to the AWGS 2019, CC and Ishii are recommended for sarcopenia screening in older Chinese adults.


Sarcopenia , Humans , Male , Female , Middle Aged , Aged , Sarcopenia/diagnosis , Sensitivity and Specificity , ROC Curve , China
4.
Food Chem ; 444: 138631, 2024 Jun 30.
Article En | MEDLINE | ID: mdl-38325079

Naringenin (NGE), a typical flavanone abundant in citrus fruits, exhibits remarkable antioxidant activities. However, its low solubility in oil restricts its widespread use in inhibiting lipid oxidation. In this study, we present a novel and effective approach to address this limitation by developing a naringenin-phospholipid complex (NGE-PC COM). Comprehensive analytical techniques including Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) were employed to confirm the formation of the NGE-PC COM and elucidate the interaction mechanism between NGE and phospholipids molecules. Notably, the oil-solubility of NGE was significantly enhanced by approximately 2700-fold when formulated as a phospholipid complex in soybean oil. The improved oil-solubility of NGE-PC COM enabled effective inhibition of oil thermal oxidation under high temperature conditions. Generally, this investigation proposed a novel and promising strategy for employing flavanones with strong antioxidant activities to enhance the thermal oxidative stability of edible oil during heating processes.


Flavanones , Phospholipids , Phospholipids/chemistry , Soybean Oil , Antioxidants , Heating , Flavanones/chemistry , Solubility , Oxidative Stress , Calorimetry, Differential Scanning , Spectroscopy, Fourier Transform Infrared/methods , X-Ray Diffraction
5.
Adv Mater ; 36(8): e2309679, 2024 Feb.
Article En | MEDLINE | ID: mdl-38051134

The ability of n-type polymer thermoelectric materials to tolerate high doping loading limits further development of n-type polymer conductivity. Herein, two alcohol-soluble n-type polythiophene derivatives that are n-PT3 and n-PT4 are reported. Due to the ability of two polymers to tolerate doping loading more significantly than 100 mol%, both achieve electrical conductivity >100 S cm-1 . Moreover, the conductivity of both polythiophenes remains almost constant at high doping concentrations with excellent doping tunability, which may be related to their ability to overcome charging-induced backbone torsion and morphology change caused by saturated doping. The characterizations reveal that n-PT4 has a high doping level and carrier concentration (>3.10 × 1020  cm-3 ), and the carrier concentration continues to increase as the doping concentration increases. In addition, doping leads to improved crystal structure of n-PT4, and the crystallinity does not decrease significantly with increasing doping concentration; even the carrier mobility increases with it. The synergistic effect of these two leads to both n-PT3 and n-PT4 achieving a breakthrough of 100 in conductivity and power factor. The DMlmC-doped n-PT4 achieves a power factor of over 150 µW m-1  K-2 . These values are among the highest for n-type organic thermoelectric materials.

6.
Shock ; 59(4): 560-568, 2023 04 01.
Article En | MEDLINE | ID: mdl-36719429

ABSTRACT: Purpose : Sepsis is the leading cause of death in patients with severe acute pancreatitis (SAP) in the intensive care unit (ICU). Early prediction of sepsis secondary to SAP developed in the late phase and of related mortality can enable appropriate treatment and improve outcomes. This study was conducted to evaluate the predictive value of presepsin in ICU patients with SAP at the early stage and compared it with established blood markers and scoring systems. Methods : This retrospective study enrolled 48 septic patients and 53 nonseptic patients admitted to ICU with SAP. Presepsin and other blood markers (procalcitonin, C-reactive protein, IL-6, white blood cell, and serum creatinine) on days 1, 3, and 7 after enrollment as well as scoring systems were assessed to predict secondary sepsis. Outcomes were evaluated at ICU discharge and on days 28 and 90. Results : Presepsin levels (on days 1, 3, and 7) were significantly higher in septic patients than in nonseptic patients. Presepsin levels showed an increasing trend over time in both sepsis and nonsepsis groups, but concentrations increased more rapidly in the sepsis group than in the nonsepsis group. Among the analyzed biomarkers, presepsin was the only blood marker independently associated with sepsis secondary to SAP on days 3 and 7, and presepsin on day 3 was independently associated with mortality at ICU discharge and on days 28 and 90. It showed similar or even better predictive accuracy for both secondary sepsis and mortality than procalcitonin and Sequential Organ Failure Assessment score. Conclusion : Presepsin could be a valuable early predictor of secondary sepsis and mortality in patients admitted to the ICU with SAP and may serve as an indicator for early risk stratification.


Pancreatitis , Sepsis , Humans , Retrospective Studies , Procalcitonin , Acute Disease , Pancreatitis/diagnosis , Biomarkers , Intensive Care Units , Peptide Fragments , Lipopolysaccharide Receptors , Prognosis
7.
AAPS PharmSciTech ; 24(1): 36, 2023 Jan 12.
Article En | MEDLINE | ID: mdl-36635447

The current study aimed to improve the poor solubility of albendazole (ABZ) by means of phospholipid complexation, hence to improve its oral bioavailability. The solvent-evaporation method for ABZ-phospholipid complex (ABZ-PC) preparation was established for the first time. And a systematic optimization of preparation conditions of ABZ-PC was performed. Physicochemical studies of ABZ-PC were performed with FTIR, DSC, and XRD measurements to confirm the formation of the ABZ-PC and reveal the interaction mechanism between ABZ and phospholipid molecules. Solubility determination and morphological characterization were applied to verify the solubility improvement of prepared ABZ-PC. Moreover, the pharmacokinetic performance of ABZ-PC was further evaluated in vivo compared with raw materials of ABZ. Under optimal preparation conditions, the AE of ABZ-PC could be approximately 100%. Physicochemical studies indicated that the P = O group in the phospholipid molecule would interact with the N-H group in the ABZ molecule through hydrogen bonds and ABZ was dispersed in an amorphous state after being prepared into ABZ-PC. The aqueous solubility of ABZ-PC in deionized water (pH7.0) improved by 30-folds than free ABZ, and the AUC0-t of ABZ-PC was significantly increased by 2.32 times in comparison with raw materials of ABZ through oral administration. The current study developed an effective method for the phospholipid complexation of ABZ. With significantly improved solubility in an aqueous environment, the prepared ABZ-PC exhibited improved oral bioavailability and pharmacokinetic characteristics indicating it could be potentially applied in the oral drug delivery of ABZ.


Albendazole , Phospholipids , Rats , Animals , Albendazole/chemistry , Biological Availability , Rats, Sprague-Dawley , Phospholipids/chemistry , Drug Delivery Systems , Solubility , Water/chemistry , Administration, Oral
8.
Exp Dermatol ; 32(2): 135-145, 2023 02.
Article En | MEDLINE | ID: mdl-36251463

Psoriasis is a chronic recurrent inflammatory skin disease that is characterized by abnormal proliferation and differentiation of keratinocytes (KCs), angiogenesis and skin inflammation. Transfer RNA fragments (tRFs) are tRNA-derived small RNAs (tsRNAs), which possess regulatory functions in many diseases. Their potential roles in the pathological development of psoriasis have not been established. We first identified differentially expressed (DE) tRFs from psoriatic skin lesions using small RNA sequencing, and collected additional clinical samples for validation. Then, we investigated the function and mechanism of target tRFs in vitro. As a result of our investigation: we identified 234 DE transcripts in psoriatic skin lesions compared with normal controls. Further functional analysis showed the downregulation of tRF-Ile-AAT-019 in psoriatic lesions plays a critical role in pathogenesis since it could target 3'UTR of the serine protease serpin protein E1 (SERPINE1) gene. We next demonstrated that tRF-Ile-AAT-019 could suppress SERPINE1, thus leading to decreased expressions of vascular endothelial growth factor but increased expressions of keratinocytes (KCs) differentiation markers including Keratin1 and Involucrin. In conclusion, tRF-Ile-AAT-019 plays a protective role in the pathological progression of psoriasis via targeting SERPINE1, resulting in regulation of KCs differentiation and vascular proliferation biomarkers and providing a potential novel targeting pathway for the disease treatment.


Psoriasis , RNA , Humans , Vascular Endothelial Growth Factor A/metabolism , RNA, Transfer/genetics , RNA, Transfer/metabolism , Down-Regulation
9.
Int Wound J ; 20(6): 2376-2385, 2023 Aug.
Article En | MEDLINE | ID: mdl-36527235

Ozone is a highly reactive oxidant molecule consisting of triatomic oxygen atoms. Ozone therapy can be achieved using ozonated hydrotherapy, ozonated oil, ozone autohemotherapy, and other innovative dosage forms of ozone products. Ozone is frequently used as a complementary therapy for various cutaneous diseases, including infectious skin diseases, wound healing, eczema, dermatitis, psoriasis, axillary osmidrosis, diabetic foot, and pressure ulcers. In addition, several studies have reported the superior potential of ozone therapy for improving skin and gut microbiomes, as well as antitumour and antiaging treatment. Ozone therapy is an emerging treatment strategy that acts via complex mechanisms, including antioxidant effects, immunomodulatory capacity, and modulation of local microcirculation. Studies assessing the mechanism of ozone have gradually expanded in recent years. This review article aims to summarise and explore the possible molecular biological mechanisms of ozone in cutaneous diseases and provide compelling theoretical evidence for the application of ozone in cutaneous diseases.


Ozone , Skin Diseases, Infectious , Skin Diseases , Humans , Skin Diseases/drug therapy , Skin , Ozone/therapeutic use , Wound Healing
10.
Chem Asian J ; 17(9): e202200031, 2022 May 02.
Article En | MEDLINE | ID: mdl-35267242

Coordination polymers (CPs) display great potential for the development of highly active photocatalysts. Herein, we report the fabrication of a highly crystalline CP, [Ag2 BTT]n (BTT=benzene-1,2,4,5-tetrathiol). The crystal structure of [Ag2 BTT]n was resolved and its performance for photocatalytic oxidation of thioanisole was explored. [Ag2 BTT]n is highly active and selective for the photo-oxidation of sulfides to sulfoxides under mild conditions, that is, in air, at room temperature and in the absence of a sacrificial reagent, co-catalyst or redox mediator.

11.
Pharmacol Res ; 177: 106089, 2022 03.
Article En | MEDLINE | ID: mdl-35065202

BACKGROUND: Our study sought to investigate the efficacy and safety of bivalirudin versus those of unfractionated heparin (UFH) in patients undergoing extracorporeal membrane oxygenation (ECMO). METHODS: PubMed, EMBASE and Cochrane Library were searched for studies enrolling ECMO patients on bivalirudin and UFH (from inception till July 2021). Meta-analysis was conducted. The I2 statistic and p value were used in measuring heterogeneity, and random effects or fixed-effect model was adopted. The Newcastle-Ottawa Scale was used for the risk of bias assessment. Sensitivity and subgroup analyses were undertaken. We performed Egger's test to evaluate publication bias. RESULTS: Fourteen eligible retrospective observational studies with 1501 subjects were identified. Compared with UFH, bivalirudin significantly reduced the risk of in-circuit thrombosis (OR = 0.44, 95% CI [0.31-0.61], p = 0.000), thrombosis (OR = 0.61, 95% CI [0.45-0.83], p= 0.002) and hospital mortality (OR = 0.78, 95% CI [0.61-0.99], p = 0.04) and had a positive impact on survival ECMO (OR = 1.50, 95% CI [1.04-2.16], p= 0.032). Decrease in risk of bleeding (OR = 0.36, 95% CI [0.14-0.91], p = 0.031) associated with bivalirudin was observed. Sources of heterogeneity were identified, and sensitivity analysis revealed similar results. CONCLUSION: Our meta-analysis suggested that bivalirudin was associated with the decreased risk of in-circuit thrombosis, thrombosis, hospital mortality and bleeding in patients on ECMO and improved survival ECMO, indicating the superiority of bivalirudin to UFH in terms of efficacy and safety.


Extracorporeal Membrane Oxygenation , Thrombosis , Adult , Anticoagulants/adverse effects , Child , Extracorporeal Membrane Oxygenation/adverse effects , Hemorrhage/chemically induced , Heparin/adverse effects , Hirudins , Humans , Peptide Fragments/adverse effects , Recombinant Proteins/adverse effects , Retrospective Studies , Thrombosis/drug therapy , Thrombosis/prevention & control , Treatment Outcome
12.
Mater Horiz ; 9(1): 147-163, 2022 01 04.
Article En | MEDLINE | ID: mdl-34542132

Adaptive devices, which aim to adjust electrical behaviors autonomically to external stimuli, are considered to be attractive candidates for next-generation artificial perception systems. Compared with typical electronic devices with stable signal output, adaptive devices possess unique features in exhibiting dynamic fitness to varying environments. To meet this requirement, increasing efforts have been made focusing on developing new materials, functional interfaces and novel device geometry for sensory perception applications. In this review, we summarize the recent advances in materials and devices for mimicking sensory adaptation. Keeping this in mind, we first introduce the fundamentals of biological sensory adaptation. Thereafter, the recent progress in mimicking sensory adaptation, such as tactile and visual adaptive systems, is overviewed. Moreover, we suggest five strategies to construct adaptive devices. Finally, challenges and perspectives are proposed to highlight the directions that deserve focused attention in this flourishing field.


Electronics , Touch
13.
BMC Med Educ ; 21(1): 606, 2021 Dec 09.
Article En | MEDLINE | ID: mdl-34879860

BACKGROUND: In this study, we applied the small private online course (SPOC) and team-based learning (TBL) blended teaching model to dermatology and venereology to ensure a higher quality learning experience for clinical medical students. METHODS: A total of 52 fifth-grade clinical undergraduates from Xiangya School of Medicine of Central South University were randomly divided into an experimental (n = 26) and a control group (n = 26). In March 2018, we used the SPOC and TBL blended teaching model in the experimental group and explored the effects of innovative teaching in the dermatology and venereology course, compared with the control group receiving the conventional teaching method. We analyzed the two groups' theoretical assessment scores and questionnaire results to evaluate the efficiency of the new pedagogy. RESULTS: Students in the experimental group had a better understanding than the control group of the dermatology and venereology content and higher scores on the case analysis questions in the final theoretical examination. The results revealed that the majority of the experimental group students agreed that the novel teaching model blended with SPOC&TBL helped them significantly stimulate motivation and develop their ability in self-directed learning, independent thinking, literature retrieval, presentation board, teamwork, communication, and systematic clinical thinking. The teaching satisfaction survey of the two groups showed that the students' satisfaction in the experimental group was significantly higher than in the control group (p < 0.05). CONCLUSIONS: The SPOC&TBL teaching model is better than the traditional one in enriching students' professional knowledge and cultivating their comprehensive ability. It can effectively promote educational quality, improve students' learning effects, and enhance their satisfaction. This method has broad application prospects.


Dermatology , Students, Medical , Venereology , Educational Measurement , Humans , Problem-Based Learning , Teaching
14.
Ann Transl Med ; 9(20): 1582, 2021 Oct.
Article En | MEDLINE | ID: mdl-34790788

BACKGROUND: Regional excessive iron overload is pernicious to motor functions and cognitive functioning of the brain. The aim of this research was to utilize quantitative susceptibility mapping (QSM) to inspect brain iron accumulation in patients with hypertension (HP), and to evaluate whether it is correlated with physiological parameters. METHODS: Thirty-one HP and 31 age- and sex-matched healthy controls (HC) were included. All participants underwent brain magnetic resonance imaging (MRI), and QSM data were obtained. Differences in brain iron deposition in deep gray matter nuclei of participants were compared between HP and HC. The correlations between iron deposition, body mass index (BMI), maximum systolic blood pressure (SBP), and diastolic blood pressure (DBP) were analyzed. RESULTS: The HP group showed increased susceptibility values in the caudate nucleus (CA), putamen (PU), globus pallidus (GP), and dorsal thalamus (TH), compared with the HC group. There was a significant positive correlation between BMI and the susceptibility values in the dentate nucleus (DN); the maximum SBP and DBP were positively correlated with magnetic susceptibility of the CA, PU, GP, and TH, respectively. CONCLUSIONS: These results are indicative of the role of overload brain iron in deep brain gray matter nuclei in HP and suggest that HP is associated with excess brain iron in certain deep gray matter regions.

15.
Angew Chem Int Ed Engl ; 59(50): 22602-22609, 2020 Dec 07.
Article En | MEDLINE | ID: mdl-32893955

Conductive coordination polymers (CPs) have potential in a wide range of applications because of their inherent structural and functional diversity. Three electrically conductive CPs (Cux C6 S6 , x=3, 4 or 5.5) derived from the same organic linker (benzenehexathiol) and metal node (copper(I)) were synthesized and studied. Cux C6 S6 materials are organic-inorganic hybrid copper sulfides comprising a π-π stacking structure and cooper sulfur networks. Charge-transport pathways within the network facilitate conductivity and offer control of the Fermi level through modulation of the oxidation level of the non-innocent redox-active ligand. Two Cux C6 S6 (x=4 or 5.5) CPs display high electrical conductivity and they feature a tunable structural topology and electronic structure. Cu4 C6 S6 and Cu5.5 C6 S6 act as degenerate semiconductors. Moreover, Cu5.5 C6 S6 is a p-type thermoelectric material with a ZT value of 0.12 at 390 K, which is a record-breaking performance for p-type CPs.

16.
Angew Chem Int Ed Engl ; 59(47): 20873-20878, 2020 Nov 16.
Article En | MEDLINE | ID: mdl-32749045

3D well-crystallized metal-organic frameworks (MOFs), M-THBQ (M=Fe, Co, Mn, THBQ=tetrahydroxybenzoquinone), are synthesized and characterized. Their structures are determined as cubic cell in the group of Pm 3 ‾ from powder X-ray diffraction data, and their properties of electronic, magnetic and spectroscopic are also investigated. They are all semiconductors, and Fe-THBQ exhibits the air-stable n-type thermoelectric characteristic as its Seebeck coefficient reaches -130 µV K-1 , and the electrical conductivity is 2.7×10-4  S cm-1 at 300 K. Additional, M-THBQ are paramagnetic, and the value of Weiss constant of Fe-THBQ is -219.37 K, indicating the existence of robust intramolecular antiferromagnetic exchanges. Meanwhile, they display strong absorption bands in the range of 220 to 1000 nm, suggest M-THBQ could have the potential to become photoabsorbers, and Fe-THBQ exhibits a narrow band gap of 0.63 eV according to the ultraviolet absorption edge spectrum.

17.
ACS Appl Mater Interfaces ; 12(26): 29540-29548, 2020 Jul 01.
Article En | MEDLINE | ID: mdl-32506899

Because of the high mobility and Seebeck coefficient, pentacene (PEN) is a promising candidate for organic small-molecule thermoelectric (TE) materials. However, the low intrinsic conductivity impedes its application in thermoelectricity. In this work, hexacyano-trimethylene-cyclopropane (CN6-CP) is employed as the dopant for PEN via constructing bilayer-structured thin films. The almost intact crystallinity and high charge carrier generation efficiency of these interface-doped PEN films ensure their high conductivity. Time of flight secondary ion mass spectrometry was applied to demonstrate the diffusion of dopant molecules into the PEN layer. UV-vis spectral analysis reveals that integral charge transfer happens between the PEN and CN6-CP molecules. The doping process is further characterized by electron spin-resonance, ultraviolet photoelectron spectroscopy, and X-ray photoelectron spectroscopy analysis. Under optimized conditions, the conductivity of the PEN film deposited on the SiO2/Si substrate can reach up to 10.1 S cm-1. To the best of our knowledge, this is the highest conductivity ever reported for doped PEN thin films. The optimal TE performance with a power factor of 36.4 µW m-1 K-2 can be achieved in the PEN/CN6CP thin film with a Seebeck coefficient and conductivity of 199 µV K-1 and 9.2 S cm-1, respectively. This result shows that interface doping with a strong electron acceptor is a promising approach for optimizing the TE performance of small molecular organic semiconductors.

18.
Chemistry ; 26(56): 12868-12873, 2020 Oct 06.
Article En | MEDLINE | ID: mdl-32430943

Metal-bis(dithiolene) is one of the most promising structures showing redox activity, excellent electron transport and magnetic properties as well as catalytic activities. Perthiolated coronene (PTC), an emerging highly symmetric ligand containing the smallest graphene nanoplate was employed to manufacture a hybrid material with fused metal-bis(dithiolene) and graphene nanoplate, and it has been demonstrated as an efficient strategy for the construction of multifunctional materials recently. Herein, Co-PTC, a 2D MOF containing Co-bis(dithiolene) and coronene units is prepared via a homogeneous reaction for the first time as powder samples, which are bar-shaped microparticles composed of nanosheets. A neutral formula of [Co3 (C24 S12 )]n is verified for Co-PTC. Co-PTC plays an ultrahigh conductivity of approximately 45 S cm-1 at room temperature as compressed samples, which is among the highest value ever reported for the compressed powder samples of conducting MOFs. Moreover, Co-PTC exhibits good electrocatalytic performance in the hydrogen evolution reaction (HER) with a Tafel slope of 189 mV decade-1 and an operating overpotential of 227 mV at 10 mA cm-1 with pH=0, as well as a remarkable stability in the extremely acidic aqueous solutions, which is the best hydrogen evolution properties among metal-organic compounds.

19.
ACS Appl Mater Interfaces ; 11(47): 44026-44035, 2019 Nov 27.
Article En | MEDLINE | ID: mdl-31738515

It is challenging to achieve highly efficient thermoelectric materials due to the conflicts between thermopower (Seebeck coefficient) and electrical conductivity. These parameters are the core factors defining the thermoelectric property of any material. Here, we report the use of isovalent substitution as a tool to decouple the interdependency of the Seebeck coefficient and the electrical properties of cerium-doped bismuth selenide thermoelectric material. With this strategy, we can achieve a simultaneous increase in both the electrical conductivity and the Seebeck coefficient of the material by tuning the concentration of cerium doping, due to formation of neutral impurities and consequently the improvement of carrier mobility. Our theoretical calculation reveals a downward shift of the valence band with cerium concentration, which influences the thermoelectric enhancement of the synthesized materials. Finally, an order of magnitude enhancement of the figure of merit is obtained due to isovalent substitution, thus providing a new avenue for enhancing the thermoelectric performance of materials.

20.
Adv Sci (Weinh) ; 5(10): 1800947, 2018 Oct.
Article En | MEDLINE | ID: mdl-30356915

New conducting polymers polythieno[3,4-b]thiophene-Tosylate (PTbT-Tos) are prepared by solution casting polymerization. Through tuning the alkyl group of TbT, the electrical conductivity can be effectively enhanced from 0.0001 to 450 S cm-1. Interestingly, the electrical conductivity of PTbT-C1-Tos increases significantly from 450 S cm-1 at room temperature to 4444 S cm-1 at 370 K, which is disparate from polyethylenedioxythiophene-Tos exhibiting metallic conducting behavior. Quasi-reversible phase transformation with temperature from 3D crystallites to lamellar-stacking coincides with the increasing electrical conductivity of PTbT-C1-Tos with heating. Methyl-substituted PTbT-Tos with the best electrical property is further utilized for thermoelectrics and a power factor as high as 263 µW m-1 K-1 is obtained. It is believed that PTbT-Tos will be a promising family of conducting polymers for solution-processed organic electronics.

...