Publications by authors named "Weiqing Yang"

76 Publications

Electric-Field-Induced Ion Migration Behavior in Methylammonium Lead Iodide Perovskite.

J Phys Chem Lett 2021 Jul 23:7106-7112. Epub 2021 Jul 23.

Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, China.

Ionic movement inside organometal halide perovskites (OMHP) materials has been widely reported to be linked with stability issues in the perovskite-based optoelectronic devices. However, the dynamic processes of the ionic movement and how they influence the devices are still not well-understood. In this work, we applied an external electric field to the CHNHPbI crystal and simultaneously monitored the PL behaviors. Two successive PL responses were observed in the same location of the crystal. First, an irreversible PL quenching was observed caused by the photo-annealing effect under an electric field accompanied by a permanent morphology change. The annealed area also showed reversible PL variation, which was attributed to the activation-deactivation of the radiative recombination centers induced by the migration of the iodine ions. Such results can help us gain a deep insight into how the ionic movements in OMHPs influence the performance of the perovskite-based optoelectronic devices under working conditions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.jpclett.1c01803DOI Listing
July 2021

Chain-prolongated ionic liquid electrolyte for low self-discharge all-solid-state supercapacitors at high temperature.

ChemSusChem 2021 Jul 20. Epub 2021 Jul 20.

Southwest Jiaotong University, Materials Science and Engneering, No. 111, North First, Section 2, 610031, Chengdu, CHINA.

High-power and high-safety enable supercapacitors to work efficiently at high temperatures. However, the high-temperature-induced excessively ion-transferring of electrolyte would severely aggregate the previously-overlooked yet highly-detrimental self-discharge behavior. Herein, we designed a poly (ethylene oxide) (PEO), bentonite clay & ionic liquid (IL) solid electrolytes (PCE:[email protected] 4 , PCB:[email protected] 4 and PCH:[email protected] 4 ) for dramatically self-discharge-lowered all-solid-state supercapacitors at high temperature of 70℃ via prolonging chain (EMIM + < BMIM + < HMIM + ). Synergistically benefiting from cations-adsorbed action and high-temperature stabilizer of bentonite clay, PCH-based (HMIMBF 4 as the IL) supercapacitors deliver extremely-low self-discharge rate of only 30.7% voltage-dropping at 70℃ for 10 h (44.5% even for 38 h), much lower than that of traditional liquid supercapacitors (63.7% at 70℃ for 10h). Further, this better high-temperature self-discharge behavior was proved to be from the decreased diffusion controlled Faradaic process. Based on the longer HMIM + , soft-packaged supercapacitors can remarkably deliver low self-discharge rate and can work persistently at 70℃. Clearly, this chain-prolongated strategy provides a new possibility for the suppression of the self-discharge behavior of supercapacitor, and further realize the long-term energy storage of supercapacitor at high temperature.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/cssc.202101294DOI Listing
July 2021

Hierarchically Microstructure-Bioinspired Flexible Piezoresistive Bioelectronics.

ACS Nano 2021 Jun 15. Epub 2021 Jun 15.

Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031, P. R. China.

The naturally microstructure-bioinspired piezoresistive sensor for human-machine interaction and human health monitoring represents an attractive opportunity for wearable bioelectronics. However, due to the trade-off between sensitivity and linear detection range, obtaining piezoresistive sensors with both a wide pressure monitoring range and a high sensitivity is still a great challenge. Herein, we design a hierarchically microstructure-bioinspired flexible piezoresistive sensor consisting of a hierarchical polyaniline/polyvinylidene fluoride nanofiber (HPPNF) film sandwiched between two interlocking electrodes with microdome structure. Ascribed to the substantially enlarged 3D deformation rates, these bioelectronics exhibit an ultrahigh sensitivity of 53 kPa, a pressure detection range from 58.4 to 960 Pa, a fast response time of 38 ms, and excellent cycle stability over 50 000 cycles. Furthermore, this conformally skin-adhered sensor successfully demonstrates the monitoring of human physiological signals and movement states, such as wrist pulse, throat activity, spinal posture, and gait recognition. Evidently, this hierarchically microstructure-bioinspired and amplified sensitivity piezoresistive sensor provides a promising strategy for the rapid development of next-generation wearable bioelectronics.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsnano.1c01606DOI Listing
June 2021

Air-Stable Conductive Polymer Ink for Printed Wearable Micro-Supercapacitors.

Small 2021 06 21;17(25):e2100956. Epub 2021 May 21.

Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA, 90095, USA.

Printed electronics are expected to facilitate the widespread distributed wearable electronics in the era of the Internet of things. However, developing cheap and stable electrode inks remains a significant challenge in the printed electronics industry and academic community. Here, overcoming the weak hydrophilicity of polyaniline, a low-cost, easy-fabricating, and air-stable conducting polymer (CP) ink is devised through a facile assemble-disperse strategy delivering a high conductivity in the order of 10 S cm along with a remarkable specific capacitance of 386.9 F g at 0.5 A g (dehydrated state). The additive-free CP ink is directly employed to print wearable micro-supercapacitors (MSCs) via the spray-coating method, which deliver a high areal capacitance (96.6 mF cm ) and volumetric capacitance (26.0 F cm ), outperforming most state-of-the-art CP-based supercapacitors. This work paves a new approach for achieving scalable MSCs, thus rendering a cost-effective, environmentally friendly, and pervasive energy solution for next-generation distributed electronics.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/smll.202100956DOI Listing
June 2021

Sputum microbiota as a potential diagnostic marker for multidrug-resistant tuberculosis.

Int J Med Sci 2021 3;18(9):1935-1945. Epub 2021 Mar 3.

Dongguan Key Laboratory of Medical Bioactive Molecular Developmental and Translational Research, Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Guangdong Medical University, Dongguan, China.

The prevalence of drug-resistant (Mtb) strains makes disease control more complicated, which is the main cause of death in tuberculosis (TB) patients. Early detection and timely standard treatment are the key to current prevention and control of drug-resistant TB. In recent years, despite the continuous advancement in drug-resistant TB diagnostic technology, the needs for clinical rapid and accurate diagnosis are still not fully met. With the development of sequencing technology, the research of human microecology has been intensified. This study aims to use 16 rRNA sequencing technology to detect and analyze upper respiratory flora of TB patients with anti-TB drug sensitivity (DS, n = 55), monoresistance isoniazide (MR-INH, n = 33), monoresistance rifampin (MR-RFP, n = 12), multidrug resistance (MDR, n = 26) and polyresistance (PR, n = 39) in southern China. Potential microbial diagnostic markers for different types of TB drug resistance are searched by screening differential flora, which provides certain guiding significance for drug resistance diagnosis and clinical drug use of TB. The results showed that the pulmonary microenvironment of TB patients was more susceptible to infection by external pathogens, and the infection of different drug-resistant Mtb leads to changes in different flora. Importantly, seven novel microorganisms (Leptotrichia, Granulicatella, Campylobacter, Delfitia, Kingella, Chlamydophila, Bordetella) were identified by 16S rRNA sequencing as diagnostic markers for different drug resistance types of TB. Leptotrichia, Granulicatella, Campylobacter were potential diagnostic marker for TB patients with INH single-resistance. Delftia was a potential diagnostic marker for TB patients with RFP single drug-resistance. Kingella and Chlamydophila can be used as diagnostic markers for TB patients with PR. Bordetella can be used as a potential diagnostic marker for identification of TB patients with MDR.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.7150/ijms.53492DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8040397PMC
March 2021

Understanding the Percolation Effect in Triboelectric Nanogenerator with Conductive Intermediate Layer.

Research (Wash D C) 2021 4;2021:7189376. Epub 2021 Feb 4.

Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031, China.

Introducing the conductive intermediate layer into a triboelectric nanogenerator (TENG) has been proved as an efficient way to enhance the surface charge density that is attributed to the enhancement of the dielectric permittivity. However, far too little attention has been paid to the companion percolation, another key element to affect the output. Here, the TENG with MXene-embedded polyvinylidene fluoride (PVDF) composite film is fabricated, and the dependence of the output capability on the MXene loading is investigated experimentally and theoretically. Specifically, the surface charge density mainly depends on the dielectric permittivity at lower MXene loadings, and in contrast, the percolation becomes the degrading factor with the further increase of the conductive loadings. At the balance between the dielectric and percolation properties, the surface charge density of the MXene-modified TENG obtained 350% enhancement compared to that with the pure PVDF. This work shed new light on understanding the dielectric and percolation effect in TENG, which renders a universal strategy for the high-performance triboelectronics.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.34133/2021/7189376DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7881766PMC
February 2021

QuEChERS with ultrasound-assisted extraction combined with high-performance liquid chromatography for the determination of 16 polycyclic aromatic hydrocarbons in sediment.

J AOAC Int 2021 Feb 22. Epub 2021 Feb 22.

West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu 610041, China.

Background: Polycyclic aromatic hydrocarbons (PAHs) have attracted worldwide attention due to their carcinogenic, teratogenic and mutagenic effects, environmental persistence and bioaccumulation characteristics. Therefore, the sensitive, reliable and rapid detection of PAHs in sediment is of great importance.

Objective: To develop a high-performance liquid chromatography (HPLC) with fluorescence and ultraviolet detection after QuEChERS treatment for simultaneous determination of 16 U.S. Environmental Protection Agency priority PAHs in sediment samples.

Methods: The samples were ultrasonically extracted with acetone and then the supernatant was purified with a modified QuEChERS method. After centrifugation, the supernatant was injected into the HPLC system for analysis. The separation was accomplished on a ZORBAX Eclipse PAH column (150 × 4.6 mm, 3.5 μm) and the column temperature was set at 30 °C. The flow rate of the mobile phase consisting of water and acetonitrile in gradient elution mode was fixed at 0.9 mL/min. Detection was conducted on an ultraviolet detector and a fluorescence detector simultaneously. The qualitative analysis was based on retention time and the quantification was based on standard curves.

Results: Under the optimal conditions, this method showed good linearities in the range of 10-200 μg/L with correlation coefficients greater than 0.9993. The method had the limits of detection (LODs) ranging from 0.00108 to 0.314 ng/g. The mean recoveries ranged from 78.4 to 117% with the intra-day and inter-day relative standard deviations (RSDs) of 0.592-10.7 and 1.01-13.0%, respectively. The proposed method was successfully applied to the detection of 16 PAHs in sediment samples collected from the Funan River in Chengdu, China with the total contents of 431 to 2143 ng/g·dw.

Conclusions: The established method is simple, rapid, environment-friendly and cost- effective. It can be applied to the analysis of 16 PAHs in sediment samples.

Highlights: A method of QuEChERS with ultrasound-assisted extraction combined with HPLC has been established for the analysis of 16 PAHs in sediment samples and the proposed method has been successfully applied to the analysis PAHs in real sediment samples.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/jaoacint/qsab023DOI Listing
February 2021

Solving Gravimetric-Volumetric Capacitive Paradox of 2D Materials through Dual-Functional Chemical Bonding-Induced Self-Constructing Graphene-MXene Monoliths.

ACS Appl Mater Interfaces 2021 Feb 27;13(5):6339-6348. Epub 2021 Jan 27.

Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Material Science and Engineering, Southwest Jiaotong University, Chengdu 610031, P.R. China.

High electrical conductivity and all-open microstructure characteristics intrinsically endow both graphene and MXenes with superior electrochemical energy storage capability. However, the above two-dimensional (2D) thicker electrodes (>20 μm) severely dilute their unique rapid electronic-ionic transferring characteristic, posing a paradox of high gravimetric and high volumetric capacitive properties due to massively excessive macropores or an unduly restacked issue. Herein, we elaborately construct novel monolithic NH-graphene and TiCT MXene ([email protected]) composites through dual-functional induced self-assembly with the help of both covalent and hydrogen bonding interactions. Notably, much thicker monolithic [email protected] electrodes (>90 μm) fabricated by a conventional roll-coating method without any further compaction treatment can simultaneously deliver two times gravimetric (gra.) and volumetric (vol.) performance than those of pure graphene (in vol.) or MXene (in gra.) materials. Moreover, monolithic [email protected] supercapacitors can remarkably present two times energy density as that of graphene and four times as MXene, respectively. Such greatly enhanced electrochemical properties are closely related to the appropriate equilibrium of the volumetric density and the open structure, which can effectively guarantee the rapid transfer of both electrons and ions in the thick monolithic [email protected] electrodes. Undoubtedly, dual-functional chemical bonding-induced self-constructing [email protected] monoliths efficiently solve the long-existing gra. and vol. capacitive paradox of the thicker 2D materials used in supercapacitors, which will guide the design of high-performance capacitive materials and promote their practical application in electrochemical energy storage.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsami.0c21257DOI Listing
February 2021

Takeaway food in Chengdu, Sichuan province, China: Composition and nutritional value.

Asia Pac J Clin Nutr 2020 ;29(4):883-898

West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, P. R. China.

Background And Objectives: The popularity of takeaway has caused health problems. To analyse the basic nutrients and composition of popular takeaway meals in Chengdu, China.

Methods And Study Design: We randomly collected 105 takeaway meals from takeaway platforms. The quality of ingredients such as grains, vegetables, and meat were assessed and weighed. The samples were then homogenised, and the nutrients were detected following the AOAC Official Methods of Analysis.

Results: Compared with Chinese and US dietary reference intakes, the average energy, protein, salt, fat, vitamin, and available carbohydrate contents exceeded dietary recommendations for one takeaway meal. By contrast, the whole grain, vegetable, fruit, dairy product, egg, mineral, and dietary fibre contents were insufficient. Food compositions and basic nutrients differed among takeaway meals prepared with various cooking methods and meats. Fried rice had the lowest nutritional value. The fried dish set meal had high energy density. The nutrient content of poultry takeaway meals was more balanced compared with other meals assessed, and salt and fat were excessive in mixed meat meals. In addition, meatless takeaway meals tended to have high fat content because of excess vegetable oil added for better taste.

Conclusions: Takeaway meals should have lower contents of energy, fat, carbohydrate, and salt and higher contents of whole grains, vegetables, fruits, dairy products, and eggs. Attention should be paid to the high energy density of the fried dish set meal to prevent resultant health problems such as obesity. Consumers, takeaway outlets, and government agencies need to work together to address the health problems.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.6133/apjcn.202012_29(4).0025DOI Listing
January 2020

Hunan insect tea polyphenols provide protection against gastric injury induced by HCl/ethanol through an antioxidant mechanism in mice.

Food Funct 2021 Jan 23;12(2):747-760. Epub 2020 Dec 23.

Chongqing Collaborative Innovation Center for Functional Food, Chongqing University of Education, Chongqing 400067, P.R. China.

The purposes of this study were to explore the preventive and treatment effects of Hunan insect tea polyphenols (HITPs) on gastric injury in mice induced by HCl/ethanol and to investigate their molecular mechanisms of action. Both HITPs and ranitidine inhibited the formation and further deterioration of gastric mucosal lesions, reduced the secretion of gastric juice, and raised gastric juice pH compared to the control. The HITPs-H treated group had lower serum levels of motilin, substance P, and endothelin than the control group, but they had higher serum levels of vasoactive intestinal peptide and somatostatin. Mice treated with HITPs had lower serum levels of cytokines interleukin (IL)-6, IL-12, tumor necrosis factor-α (TNF-α), and interferon-γ than the control group. The activities of superoxide dismutase (SOD), nitric oxide, and glutathione peroxidase (GSH-Px) were higher in the gastric tissues of HITP-treated mice, but the malondialdehyde content was lower. Quantitative PCR analysis indicated that the mRNA expression of occludin, epidermal growth factor (EGF), EGF receptor (EGFR), vascular EGF (VEGF), inhibitor kappaB-α, cuprozinc-superoxide dismutase, manganese-superoxide dismutase, GSH-Px, neuronal nitric oxide synthase, and endothelial NOS increased significantly in the gastric tissues of HITP-treated mice. However, the activated B cell, inducible NOS, cyclooxygenase-2, TNF-α, IL-1 beta, and IL-6 mRNA expression levels in the HITPs group were lower than those in the control group. The protective effect of a high concentration (200 mg per kg bw) of HITPs on gastric injury induced by HCl/ethanol was stronger than that of a low concentration (100 mg per kg bw) of HITPs. High-performance liquid chromatography (HPLC) revealed that the HITPs contained cryptochlorogenic acid, (-)-epicatechin gallate, and isochlorogenic acid C. Taken together, our findings indicate that the HITPs played a role in the prevention of gastric damage. The antioxidant effect of the HITPs contributed to their potential value in the prevention and treatment of gastric injury. HITPs have broad prospects as biologically active substances for food development.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/d0fo02677hDOI Listing
January 2021

Quaternized Silk Nanofibrils for Electricity Generation from Moisture and Ion Rectification.

ACS Nano 2020 08 29;14(8):10600-10607. Epub 2020 Jul 29.

Group of Biomimetic Smart Materials, CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Songling Road 189, Qingdao 266101, P.R. China.

Protein nanostructures in living organisms have attracted intense interests in biology and material science owing to their intriguing abilities to harness ion transportation for matter/signal transduction and bioelectricity generation. Silk nanofibrils, serving as the fundamental building blocks for silk, not only have the advantages of natural abundance, low cost, biocompatibility, sustainability, and degradability but also play a key role in mechanical toughness and biological functions of silk fibers. Herein, cationic silk nanofibrils (SilkNFs), with an ultrathin thickness of ∼4 nm and a high aspect ratio up to 500, were successfully exfoliated from natural cocoon fibers quaternization followed by mechanical homogenization. Being positively charged in a wide pH range of 2-12, these cationic SilkNFs could combine with different types of negatively charged biological nanofibrils to produce asymmetric ionic membranes and aerogels that have the ability to tune ion translocation. The asymmetric ionic aerogels could create an electric potential as high as 120 mV in humid ambient air, whereas asymmetric ionic membranes could be used in ionic rectification with a rectification ratio of 5.2. Therefore, this green exfoliation of cationic SilkNFs may provide a biological platform of nanomaterials for applications as diverse as ion electronics, renewable energy, and sustainable nanotechnology.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsnano.0c04686DOI Listing
August 2020

Cellulose II Aerogel-Based Triboelectric Nanogenerator.

Adv Funct Mater 2020 Jul 27;30(28):2001763. Epub 2020 May 27.

School of Materials Science and Engineering Georgia Institute of Technology Atlanta GA 30332-0245 USA.

Cellulose-based triboelectric nanogenerators (TENGs) have gained increasing attention. In this study, a novel method is demonstrated to synthesize cellulose-based aerogels and such aerogels are used to fabricate TENGs that can serve as mechanical energy harvesters and self-powered sensors. The cellulose II aerogel is fabricated via a dissolution-regeneration process in a green inorganic molten salt hydrate solvent (lithium bromide trihydrate), where. The as-fabricated cellulose II aerogel exhibits an interconnected open-pore 3D network structure, higher degree of flexibility, high porosity, and a high surface area of 221.3 m g. Given its architectural merits, the cellulose II aerogel-based TENG presents an excellent mechanical response sensitivity and high electrical output performance. By blending with other natural polysaccharides, i.e., chitosan and alginic acid, electron-donating and electron-withdrawing groups are introduced into the composite cellulose II aerogels, which significantly improves the triboelectric performance of the TENG. The cellulose II aerogel-based TENG is demonstrated to light up light-emitting diodes, charge commercial capacitors, power a calculator, and monitor human motions. This study demonstrates the facile fabrication of cellulose II aerogel and its application in TENG, which leads to a high-performance and eco-friendly energy harvesting and self-powered system.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/adfm.202001763DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7357570PMC
July 2020

Manipulating Relative Permittivity for High-Performance Wearable Triboelectric Nanogenerators.

Nano Lett 2020 09 25;20(9):6404-6411. Epub 2020 Jun 25.

Department of Bioengineering, University of California, Los Angeles, Los Angeles, California 90095, United States.

As the world marches into the era of the Internet of Things (IoT), the practice of human health care is on the cusp of a revolution, driven by an unprecedented level of personalization enabled by a variety of wearable bioelectronics. A sustainable and wearable energy solution is highly desired , but challenges still remain in its development. Here, we report a high-performance wearable electricity generation approach by manipulating the relative permittivity of a triboelectric nanogenerator (TENG). A compatible active carbon (AC)-doped polyvinylidene fluoride ([email protected]) composite film was invented with high relative permittivity and a specific surface area for wearable biomechanical energy harvesting. Compared with the pure PVDF, the 0.8% [email protected] film-based TENG obtained an enhancement in voltage, current, and power by 2.5, 3.5, and 9.8 times, respectively. This work reports a stable, cost-effective, and scalable approach to improve the performance of the triboelectric nanogenerator for wearable biomechanical energy harvesting, thus rendering a sustainable and pervasive energy solution for on-body electronics.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.nanolett.0c01987DOI Listing
September 2020

Understanding the Potential Screening Effect through the Discretely Structured ZnO Nanorods Piezo Array.

Nano Lett 2020 Jun 20;20(6):4270-4277. Epub 2020 May 20.

Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031, China.

The potential screening effect of one-dimensional ZnO nanorods from carriers has been theoretically proved to severely limit its piezoelectricity, but its exact mechanism needs to be further revealed in experiments to guide the design of piezoelectric semiconductors. Here, a discretely structured design was proposed to prevent the free carriers from tunneling among adjacent ZnO nanorods for suppressing the screening effect. Piezoresponse force microscope and finite element analysis were employed in combination to uncover the underlying mechanism in experiment. Further, the output voltage of this discretely structured device was 1.62 times higher than that of the nondesigned device, which clearly authenticates this suppression behavior. Besides, this design prompts an unexpected improvement in flexibility, where the flexural modulus of this piezo-film was reduced by 35.74%. Notably, this work opens a new way to understand the potential screening effect, as expected, and to advance the development of piezo-electronics toward better piezoelectricity and more excellent flexibility.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.nanolett.0c00793DOI Listing
June 2020

Actively surveillance and appropriate patients placements' contact isolation dramatically decreased Carbapenem-Resistant Enterobacteriaceae infection and colonization in pediatric patients in China.

J Hosp Infect 2020 Mar 31. Epub 2020 Mar 31.

Department of Nosocomial Infection Control and the Clinical Microbiology Laboratory, Children's Hospital of Fudan University, Shanghai, China. Electronic address:

Background: With the increasing use of carbapenems in clinic practice, carbapenem-resistant Enterobacteriaceae (CRE) has also increased, thus posing a significant threat to human health.

Aim: To assess the effects of CRE colonization active screening and various CRE patient placements implemented in decreasing CRE infection risk.

Methods: CRE colonization screening and various CRE patient placements were performed across CRE high-risk departments (PICU, NICU, neonatal wards and hematology departments) between 2017 and 2018, respectively.

Finding: In 2018, more than 80% neonatal CRE positive patients were isolated using single room or same room isolation, and more than 50% non-neonatal patients were, with no cohort placement. The CRE nosocomial infection incidences decreased from 1.96% to 0.63% in NICU, and from 0.57% to 0.30% in neonatal wards (all P<0.05) while no significant changes were found in the other departments. The CRE colonization incidence at different length hospital stay (LOS) decreased at 8-14days and >14days LOS in CRE high-risk departments (all P<0.05). In addition, 62.5% clinical strains, 66.7% screening strains, and 74.1% nosocomial infection strains were belonged to CC17 complex group in neonatal isolates; while, 56.6%, 47.5% and 100% strains mentioned above were belonged to CC11 complex group in non-neonatal isolates respectively. The predominant carbapenemase gene was bla (98%) in neonatal and bla (70%) in non-neonatal CR-KP stains.

Conclusions: Active CRE colonization surveillance and CRE positive patient propriety placement may decrease the CRE infection risk. Neonatal and non-neonatal CR-KP isolates showed different CRE molecular characteristics, which could further benefit CRE infection precaution and antibiotic therapy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jhin.2020.03.031DOI Listing
March 2020

Unraveling and Regulating Self-Discharge Behavior of TiCT MXene-Based Supercapacitors.

ACS Nano 2020 Apr 23;14(4):4916-4924. Epub 2020 Mar 23.

Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031, P.R. China.

Rich chemistry and surface functionalization provide MXenes enhanced electrochemical activity yet severely exacerbate their self-discharge behavior in supercapacitors. However, this self-discharge behavior and its related mechanism are still remaining issues. Herein, we propose a chemically interface-tailored regulation strategy to successfully unravel and efficiently alleviate the self-discharge behavior of TiCT MXene-based supercapacitors. As a result, TiCT MXenes with fewer F elements (∼0.65 atom %) show a positive self-discharge rate decline of ∼20% in comparison with MXenes with higher F elements (∼8.09 atom %). Such decline of the F elements can highly increase tight-bonding ions corresponding to an individual self-discharge process, naturally resulting in a dramatic 50% increase of the transition potential (). Therefore, the mixed self-discharge rate from both tight-bonding (contain fewer F elements) and loose-bonding ions (contain more F elements) is accordingly lowered. Through chemically interface-tailored engineering, the significantly changed average oxidation state and local coordination information on MXene affected the interaction of ion counterparts, which was evidently revealed by X-ray absorption fine structures. Theoretically, this greatly improved self-discharge performance was proven to be from higher adsorption energy between the interface of the electrode and the electrolyte by density functional theory. Therefore, this chemically interface-tailored regulation strategy can guide the design of high-performance MXene-based supercapacitors with low self-discharge behavior and will promote its wider commercial applications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsnano.0c01056DOI Listing
April 2020

Comparison of two different minimally invasive percutaneous nephrostomy sheaths for the treatment of staghorn stones.

BJU Int 2020 06 21;125(6):898-904. Epub 2020 Mar 21.

Department of Urology, The Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, China.

Objective: To compare the safety and effectiveness of using a conventional nephrostomy sheath (NS) vs using a new NS with suction and evacuation functions in minimally invasive percutaneous nephrolithotomy (MPCNL) for the treatment of staghorn stones.

Patients And Methods: A prospective and randomised study of 60 patients with staghorn stones randomly assigned into two groups of 30 patients. One group underwent MPCNL using conventional NS, whereas the other group underwent MPCNL with suction-evacuation NS (SENS). Patient demographics, stone characteristics, intraoperative data, perioperative data, and surgical results were collected and analysed.

Results: The patient demographics and stone characteristics were similar amongst the two groups. The SENS group had a significantly lower peak and a significantly lower average renal pelvic pressure (RPP) throughout the procedure. The SENS group was more efficient for stone removal and had a much shorter stone treatment time, a lesser use of the stone extractor, and ultimately a higher stone-free rate (SFR). The effects of a lower RPP and shorter stone treatment time translated into less severe postoperative complications as measured per modified Clavien grade.

Conclusion: Using SENS in MPCNL for the treatment of staghorn stones has the advantages of lower RPP, increased effectiveness in stone retrieval, decreased surgery related complications, and an improved SFR.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/bju.15031DOI Listing
June 2020

Strong Lewis Acid-Base and Weak Hydrogen Bond Synergistically Enhancing Ionic Conductivity of Poly(ethylene oxide)@SiO Electrolytes for a High Rate Capability Li-Metal Battery.

ACS Appl Mater Interfaces 2020 Mar 21;12(9):10341-10349. Epub 2020 Feb 21.

Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Material Science and Engineering, Southwest Jiaotong University, Chengdu 610031, PR China.

Solid-state composite polymer electrolytes (CPEs) usually suffer from intrinsic low ionic conductivity and a solid-solid interface, badly inhibiting their widespread commercial application in all-solid-state Li-metal battery (ASSLMB) energy storage. Herein, a synergetic strategy using strong Lewis acid-base and weak hydrogen bonds was employed for self-assembly in situ construction of three-dimensional (3D) network-structured poly(ethylene oxide) (PEO) and SiO CPEs ([email protected]). Ascribed to this synergistically rigid-flexible coupling dynamic strategy, a harmonious incorporation of monodispersed SiO nanoparticles into PEO could remarkably reduce crystallinity of PEO, significantly enhancing the ionic conductivity (∼1.1 × 10 S cm at 30 °C) and dramatically facilitating solid electrolyte interface stabilization (electrochemical stability window > 4.8 V at 90 °C). Moreover, the [email protected] ASSLMBs possess excellent rate capability over a wide temperature range (∼105 mA h g under 2 C at 90 °C), high temperature cycling capacity (retaining 90 mA h g after 100 cycles at 90 °C), and high specific capacity (146 mA h g under 0.3 C at 90 °C). Unambiguously, these high ionic conductivity CPEs along with excellent flexibility and safety can be one of the most promising candidates for high-performance ASSLMBs, evidently revealing that this synergistically rigid-flexible coupling dynamic strategy will open up a way to exploit the novel high ionic conductivity solid-state electrolytes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsami.9b20128DOI Listing
March 2020

Carbon Nanolights in Piezopolymers are Self-Organizing Toward Color Tunable Luminous Hybrids for Kinetic Energy Harvesting.

Small 2020 Feb 30;16(8):e1905703. Epub 2020 Jan 30.

Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, Sichuan, China.

Herein, an all-solid-state sequential self-organization and self-assembly process is reported for the in situ construction of a color tunable luminous inorganic/polymer hybrid with high direct piezoresponse. The primary inorganic self-organization in solid polymer and the subsequent polymer self-assembly are achieved at high pressure with the first utilization of piezo-copolymer (PVDF-TrFE) as the host matrix of guest carbon quantum dots (CQDs). This process induces the spontaneous formation of a highly ordered, microscale, polygonal, and hierarchically structured CQDs/PVDF-TrFE hybrid with multicolor photoluminescence, consisting of very thermodynamic stable polar crystalline nanowire arrays. The electrical polarization-free CQDs/PVDF-TrFE hybrids can efficiently harvest the environmental available kinetic mechanical energy with a new large-scale group-cooperation mechanism. The open-circuit voltage and short-circuit current outputs reach up to 29.6 V cm and 550 nA cm , respectively. The CQDs/PVDF-TrFE-based hybrid nanogenerator demonstrates drastically improved durable and reliable features during the real-time demonstration of powering commercial light emitting diodes. No attenuation/fluctuation of the electrical signals is observed for ≈10 000 continuous working cycles. This study may offer a new design concept for progressively but spontaneously constructing novel multiple self-adaptive complex inorganic/polymer hybrids that promise applications in the next generation of self-powered autonomous optoelectronic devices.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/smll.201905703DOI Listing
February 2020

Understanding the Ion-Sorption Dynamics in Functionalized Porous Carbons for Enhanced Capacitive Energy Storage.

ACS Appl Mater Interfaces 2020 Jan 6;12(2):2773-2782. Epub 2020 Jan 6.

State Key Laboratory of Traction Power, Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering , Southwest Jiaotong University , Chengdu 610031 , China.

Heteroatom-functionalized porous carbon has long been regarded as a promising electrode material to construct high-performance capacitive energy storage devices. However, the development of this field is seriously limited due to the lack of an in-depth understanding of the ion-sorption dynamics. Herein, the component and structure controllable N, O, and Cl codoped bimodal (micro-to-meso) porous carbons were prepared and further used as the investigated object for exploring the intrinsic ion-sorption dynamics, which is the root of the enhanced electrochemical response in capacitive energy storage devices. Voltammetry response analysis is employed to quantify the charge storage contributions from both electrostatic adsorption effect (electrical double-layer capacitance) and highly reversible redox process (pseudocapacitance). The existence of electronic capacitance enables a positive correlation between surface capacitance and the ratio of micropores. Besides, an electron-dependent correlation between the electroactive functional groups and redox reaction induced capacitance is also explored. This work will advance the capacitive energy storage field by presenting a clear understanding of the ion-sorption dynamics in the functionalized porous carbons.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsami.9b15781DOI Listing
January 2020

Intrinsically Stretchable and Shape Memory Conducting Nanofiber for Programmable Flexible Electronic Films.

ACS Appl Mater Interfaces 2019 Dec 16;11(51):48202-48211. Epub 2019 Dec 16.

School of Materials Science and Engineering, Key Laboratory of Advanced Technologies of Materials, Ministry of Education , Southwest Jiaotong University , Chengdu 610031 , China.

Recently, flexible and stretchable electronic films have been drawing increasing attention but are limited by the nature of elastomeric materials and the embedded structure; thus, these films cannot achieve long-term and stable electrical performance at certain deformation states in practical applications. Here, we report intrinsically stretchable and shape memory polycaprolactone/polyethylene glycol/silver nanowires films (PPAFs) based on a dual-layer network structure of nanofibers that can achieve both shape-fixable and deformation-reversible conductivity in the elongation range. We also demonstrate the resistance characteristic of PPAFs at the same/different deformation rates, which shows the unique memorable resistance and the variable conversion of a "conductive-insulation-conductive" state. Importantly, the change in sheet resistance of the PPAFs fixed at any rate of deformation could sustainably recover the initial sheet resistance even after cyclic thermal responses. Furthermore, we successfully develop the programmable conductivity of PPAFs as a monitoring, switching, and alarming device for shape memory cycles through the ingenious design of a microcircuit and simulation analysis using Proteus software. PPAFs show great potential for changeable characteristics in both shape and resistance for use in flexible electronic films.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsami.9b14430DOI Listing
December 2019

Mitochondrial E3 ubiquitin ligase 1 promotes autophagy flux to suppress the development of clear cell renal cell carcinomas.

Cancer Sci 2019 Nov 28;110(11):3533-3542. Epub 2019 Sep 28.

Department of Urology, The Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.

Clear cell renal cell carcinoma (ccRCC) is one of the most common malignant tumors in the urinary system. Surgical intervention is the preferred treatment for ccRCC, but targeted biological therapy is required for postoperative recurrent or metastatic ccRCC. Autophagy is an intracellular degradation system for misfolded/aggregated proteins and dysfunctional organelles. Defective autophagy is associated with many diseases. Mul1 is a mitochondrion-associated E3 ubiquitin ligase and involved in the regulation of divergent pathophysiological processes such as mitochondrial dynamics, and thus affects the development of various diseases including cancers. Whether Mul1 regulates ccRCC development and what is the mechanism remain unclear. Histochemical staining and immunoblotting were used to analyze the levels of Mul1 protein in human renal tissues. Statistical analysis of information associated with tissue microarray and The Cancer Genome Atlas (TCGA) database was conducted to show the relationship between Mul1 expression and clinical features and survival of ccRCC patients. Impact of Mul1 on rates of cell growth and migration and autophagy flux were tested in cultured cancer cells. Herein we show that Mul1 promoted autophagy flux to facilitate the degradation of P62-associated protein aggresomes and adipose differentiation-related protein (ADFP)-associated lipid droplets and suppressed the growth and migration of ccRCC cells. Levels of Mul1 protein and mRNA were significantly reduced so that autophagy flux was likely blocked in ccRCC tissues, which is potentially correlated with enhancement of malignancy of ccRCC and impairment of patient survival. Therefore, Mul1 may promote autophagy to suppress the development of ccRCC.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/cas.14192DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6825007PMC
November 2019

Surface pre-optimization of a mixed halide perovskite toward high photoluminescence quantum yield in the blue spectrum range.

Nanoscale 2019 Aug;11(32):15206-15215

Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031, PR China.

The photoluminescence quantum yields (PLQYs) of all-inorganic halide perovskites in the green and red spectral ranges have approached over 90%, overwhelmingly arousing burgeoning interests for creating a revolution in next-generation high-definition displays. However, obtaining pure blue-emitting perovskites with high PLQYs still remains a challenge. Herein, we designed a novel strategy to pre-optimize CsPbCl3 quantum dots (QDs) using praseodymium(iii) chloride (PrCl3), and then efficient blue-emitting CsPbBrxCl3-x QDs were obtained through halide exchange between the optimized CsPbCl3 and efficient CsPbBr3 QDs. Specifically, the PrCl3 optimization simultaneously and efficiently passivated the surface vacancy defects and appropriately reduced the surface long-chain organic ligands of the CsPbCl3 QDs, synergistically eliminating the deep trap states, and hence considerably suppressing nonradiative recombination. As a result, the radiative recombination rate was enhanced by more than one order of magnitude from 4.3 to 79 μs-1. Benefiting from this, the blue-emitting CsPbBrxCl3-x QDs exhibited an admirable PLQY of up to 89%, which is competitive compared with that of the state-of-the-art red and green-emitting perovskites. This strategy provides a unique understanding regarding the low PLQY of blue-emitting perovskites and an efficient method to boost it, which is especially attractive for constructing efficient blue and white light-emitting diodes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c9nr05217hDOI Listing
August 2019

Synthetic Biopigment Supercapacitors.

ACS Appl Mater Interfaces 2019 Aug 12;11(33):30360-30367. Epub 2019 Aug 12.

College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering , Sichuan University , Chengdu 610065 , China.

Biomass-based energy storage devices have drawn increasing attention owing to their renewability and sustainability, particularly that the heteroatom-doped carbons derived from natural polymers are regarded as the promising candidates in discovering advanced electrode materials for supercapacitors. This work has developed a facile one-pot fabrication strategy toward synthetic pheomelanin nanoparticles with controllable size and chemical composition (i.e., sulfur content) via the copolymerization of dopamine and cysteine. The resulting synthetic pigment materials possess outstanding thermal stability and are able to directly transform into monodispersed S,N-codoped carbon spheres with unaltered morphology. Compared with conventional polydopamine-based carbon spheres, the present carbonized pheomelanin nanoparticles with electroactive sulfur atoms could possess lower charge-transfer resistance and consequently higher specific capacitance (e.g., 243 F g at 1 A g). This research continues to inspire researchers to develop new kinds of energy storage materials based on synthetic biopigment materials.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsami.9b10956DOI Listing
August 2019

Aqueous Phase Exfoliating Quasi-2D CsPbBr Nanosheets with Ultrahigh Intrinsic Water Stability.

Small 2019 Aug 28;15(34):e1901994. Epub 2019 Jun 28.

Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, China.

All-inorganic cesium lead halide perovskite nanocrystals (NCs) have emerged as attractive optoelectronic materials due to the excellent optical and electronic properties. However, their environmental stability, especially in the presence of water, is still a significant challenge for their further commercialization. Here, ultrahigh intrinsically water-stable all-inorganic quasi-2D CsPbBr nanosheets (NSs) via aqueous phase exfoliation method are reported. Compared to conventional perovskite NCs, these unique quasi-2D CsPbBr nanosheets present an outstanding long-term water stability with 87% photoluminescence (PL) intensity remaining after 168 h under water conditions. Moreover, the photoluminescence quantum yields (PLQY) of quasi-2D CsPbBr NSs is up to 82.3%, and these quasi-2D CsPbBr NSs also present good photostability of keeping 85% PL intensity after 2 h under 365 nm UV light. Evidently, such quasi-2D perovskite NSs will open up a new way to investigate the intrinsic stability of all-inorganic perovskites and further promote the commercial development of perovskite-based optoelectronic and photovoltaic devices.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/smll.201901994DOI Listing
August 2019

Highly microporous carbon with nitrogen-doping derived from natural biowaste for high-performance flexible solid-state supercapacitor.

J Colloid Interface Sci 2019 Jul 3;548:322-332. Epub 2019 Apr 3.

(a)State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031, P. R. China; (b)Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031, P. R. China. Electronic address:

Highly microporous carbon material with nitrogen doping has been synthesized via a facile one-step approach by employing natural biowaste miscellaneous wood fibers derived hydrochar as precursor and melamine as nitrogen source respectively. The added melamine not only results in the incorporation of some nitrogen into the carbon framework but also increases the specific surface area of carbon material. Such resultant N-doped microporous carbon possesses the functionalized nitrogen doping (1.75 at. %), a large specific surface area (∼1807 m g) and abundant highly interconnected micropores. Benefiting from the synergistic effect of high specific surface area, well-developed pore size distribution and functionalized groups, this carbon material delivers a high specific capacitance of 345 F g at 0.5 A g, an excellent capacitance retention with 270 F g at up to 30 A g, and a remarkable cycle ability with 91.3% retention after 10,000 cycles at 5.0 A g. Based on it, the as-developed flexible symmetric solid-state supercapacitor delivers a high energy density of 7.92 W h kg at the power density of 250 W kg. Evidently, this work provides a facile and cost-effective route for functionalized natural biowaste-based carbon materials and further opens up a way for highly value-added recycling of biowaste-like materials.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jcis.2019.04.005DOI Listing
July 2019

Stretchable Micromotion Sensor with Enhanced Sensitivity Using Serpentine Layout.

ACS Appl Mater Interfaces 2019 Apr 21;11(13):12261-12271. Epub 2019 Mar 21.

Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering , Southwest Jiaotong University , Chengdu 610031 , P. R. China.

The application of the serpentine mesh layout in stretchable electronics provides a feasible method to achieve the desired stretchability by structural design instead of modifying the intrinsic mechanical properties of the applied materials. However, previous works using the serpentine layout mainly focused on the optimization of structural stretchability. In this paper, the serpentine mesh design concept is used to transform the high-performance but hard-to-stretch piezoelectric film into a stretchable form. The serpentine layout design strategies for the piezoelectric film, which aim at not only desired stretchability but also high utilization of the strain in the piezoelectric film during deformation, are discussed with experimental and computational results. A stretchable micromotion sensor with high sensitivity is realized using the piezoelectric film with a serpentine layout. Human voice recognition applications of the sensor, including speech pattern recognition with machine learning, are demonstrated with the sensor integrated with a wireless module. The stretchable micromotion sensor with a serpentine layout illustrates the broader application of serpentine layout design in the functional materials of stretchable electronics, which can further extend the range of available functional materials for novel stretchable electronic devices.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsami.8b22613DOI Listing
April 2019

A piezo-phototronic enhanced serrate-structured ZnO-based heterojunction photodetector for optical communication.

Nanoscale 2019 Feb;11(6):3021-3027

Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031, China.

ZnO-based heterojunction photodetectors have been widely used in various fields such as optical imaging and health monitoring. As for the traditional planar heterojunction interface, their limited optical absorption will place restrictions on the full photoelectric potential of ZnO nanorods, which severely restrains the commercial applications of ZnO-based photodetectors. Herein, using an intrinsically octahedral structure of p-type Cu2O and one-dimensional ZnO arrays, the newly designed serrate-structured heterojunction was constructed, whose unique serrate-structured interface of ZnO/Cu2O is highly conducive to the aggrandizing of optical absorption. The as-fabricated photodetector could achieve a high on/off ratio up to 1000 and an optimum photocurrent of 24.90 μA under 1.41 mW mm-2 (405 nm) illumination without bias voltage, which was 2.5 times higher than that of the planar-structured photodetector, and the response time was as quick as 1.6 ms. When the additional external strain was 0.39%, the performance was dramatically enhanced more than 5 times due to the synergism of the piezo-phototronic effect and the serrate-structured design. Based on this, we successfully developed designed photodetector arrays with an excellent optical communication performance of transmitting information. Prospectively, this kind of unique serrate-structured heterojunction design will open up a possible opportunity for high performance photodetectors based on structural engineering.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c8nr09418gDOI Listing
February 2019

Na and Pr co-doped orange-emitting CaYAlO phosphors: synthesis, luminescence properties and theoretical calculations.

Dalton Trans 2018 Dec 4;47(48):17515-17524. Epub 2018 Dec 4.

Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031, China.

A series of Na and Pr co-doped orange-emitting CaYAlO (CYAO) phosphors were prepared by a conventional high-temperature solid-state reaction method. The crystalline structure, the luminescence properties and the decay times of the as-prepared samples were systematically investigated by X-ray diffraction (XRD) and steady-state and time-resolved photoluminescence. Under ultraviolet (UV) light and blue light excitation, the CYAO:Pr phosphors exhibited orange photoluminescence emission and show potential for application in warm white LEDs, and the emission spectra of the as-prepared samples in the near-infrared (NIR) region were detected. Furthermore, Na ions were designed as charge compensators to maintain the charge balance. The luminescence intensities in the visible and NIR regions can be effectively enhanced by adjusting the doping amounts of Pr ions and Na ions. Moreover, the optical spectra of Pr in the CYAO host crystals were calculated by conventional parametric modeling based on the diagonalization of the complete 91 × 91 energy matrix. The calculated optical spectra were in good agreement with the observed ones and the obtained crystal field parameters were also in a reasonable range. This systemic study, and all of the above, will give a deep insight into the luminescence mechanism of the phosphors and then open one way to exploit the new phosphors for white LEDs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c8dt03828gDOI Listing
December 2018

Epidermis-Inspired Ultrathin 3D Cellular Sensor Array for Self-Powered Biomedical Monitoring.

ACS Appl Mater Interfaces 2018 Dec 20;10(48):41070-41075. Epub 2018 Nov 20.

Department of Materials Science and Engineering , Stanford University , Stanford , California 94305 , United States.

Sensing devices with wearability would open the door to many advanced applications including soft robotics, artificial intelligence, and healthcare monitoring. Here, inspired by the configuration of the human epidermis, we present a flexible three-dimensional (3D) cellular sensor array (CSA) via a one-step thermally induced phase separation method. The CSA was framed by the 3D cellular electret with caged piezoelectric nanoparticles, which was ultrathin (80 μm), lightweight, and highly robust. For biomedical sensing, the 3D-CSA holds a decent pressure sensitivity up to 0.19 V kPa with a response time of less than 16 ms. Owing to its rigid structural symmetry, the 3D-CSA could be identically operated from its both sides. It was demonstrated to successfully measure the human heartbeat, detect the eyeball motion for sleeping monitoring, and tactile imaging. Mimicking the functionalities of the human skin with a self-powered operation feature, the 3D-CSA was expected to represent a substantial advancement in wearable electronics for healthcare.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsami.8b14514DOI Listing
December 2018
-->