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1.
Ophthalmic Plast Reconstr Surg ; 40(3): e72-e74, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38738719

RESUMO

Due to their relatively high prevalence and commensalism, the pathogenicity of Demodex mites has been debated. Recent data, however, show Demodex to be associated with skin and ocular surface diseases such as rosacea, blepharitis, and keratitis. Here the authors report the first known case, to the best of the their knowledge, of Demodex infestation mimicking preseptal cellulitis in an adult human. A 29-year-old male bilaterally blind from advanced retinopathy of prematurity presented with a 2-month history of right-greater-than-left upper eyelid and periocular/cheek swelling, redness, and ocular discharge that did not resolve with oral antibiotics or oral steroids. Based on MRI findings, biopsies of the right lacrimal gland, right orbital fat, and right upper eyelid preseptal skin were obtained which revealed marked intrafollicular Demodex mite density and budding yeasts in the upper eyelid skin. This case serves to alert clinicians to this entity that may not otherwise be usually considered in ophthalmic clinical practice.


Assuntos
Celulite (Flegmão) , Infecções Oculares Parasitárias , Infestações por Ácaros , Humanos , Masculino , Adulto , Infestações por Ácaros/diagnóstico , Infecções Oculares Parasitárias/diagnóstico , Infecções Oculares Parasitárias/parasitologia , Diagnóstico Diferencial , Celulite (Flegmão)/diagnóstico , Celulite (Flegmão)/microbiologia , Animais , Ácaros , Doenças Palpebrais/diagnóstico , Doenças Palpebrais/parasitologia , Doenças Palpebrais/tratamento farmacológico , Pálpebras/parasitologia , Pálpebras/patologia , Imageamento por Ressonância Magnética , Biópsia , Celulite Orbitária/diagnóstico , Celulite Orbitária/microbiologia
2.
Small ; 19(22): e2301352, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36864574

RESUMO

Chemical doping of sodium is an indispensable means to optimize thermoelectric properties of PbTe materials, while a bottleneck is that an aliovalent atom doping leads to spontaneous intrinsic defects in the PbTe matrix, resulting in low dopant solubility. Therefore, it is urgent to improve the doping efficiency of Na for maximizing optimization. Here, an amazing new insight that the intentionally introduced Pb vacancies can promote Na solubility in ternary Pb1- x Nax Te is reported. Experimental analysis and theoretical calculations provide new insights into the inherent mechanism of the enhancement of Na solubility. The Pb vacancies and the resultant more dissolved Na not only synergistically optimize the carrier concentration and further facilitate the band convergence, but also induce a large number of dense dislocations in the grains. Consequently, benefiting from the self-enhancement of Seebeck coefficient and the minimization of lattice thermal conductivity, an 18% growth is obtained for the figure of merit zT in vacancy-containing Pb0.95 Na0.04 Te sample, reaching maximum zTmax  ≈ 2.0 at 823 K, which achieves an ultra-high performance in only Na-doped ternary Pb1- x Nax Te materials. The strategy utilized here provides a novel route to optimize PbTe materials and represents an important step forward in manipulating thermoelectrics to improve dopant solubility.

3.
Langmuir ; 39(19): 6914-6923, 2023 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-37141530

RESUMO

In this study, a strategy for the rapid and simple preparation of porous carbon (PC) using the microwave method was proposed. Oxygen-rich PC was synthesized by microwave irradiation in air, where potassium citrate and ZnCl2 served as the carbon source and microwave absorber, respectively. ZnCl2 achieves microwave absorption through dipole rotation, which uses ion conduction to convert heat energy in the reaction system. In addition, potassium salt etching improved the porosity of PCs. The PC prepared under optimal conditions had a large specific surface area (902 m2·g-1) and exhibited a significant specific capacitance (380 F·g-1) in the three-electrode system at 1 A·g-1. The energy and power densities of the assembled symmetrical supercapacitor device based on PC-375W-0.4 were 32.7 W·h·kg-1 and 0.65 kW·kg-1, respectively, at a current density of 1 A·g-1. Even after 5000 cycles at 5 A·g-1 current density, the excellent cycle life retained 94% of its initial capacitance.

4.
Int J Mol Sci ; 24(2)2023 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-36674754

RESUMO

A gelatin/sodium alginate-based hydrogel microsphere has been fabricated after reaction condition optimization. Macrophages (RAW246.7) and adipose mesenchymal stem cells (ADSC) have been subsequently encapsulated in the microsphere in order to construct a 3D paracrine system for wound healing treatment. The synthesized microsphere displayed neglectable cytotoxicity toward both encapsulated cells until 10 days of incubation, indicating promising biocompatibility of the microsphere. A qRT-PCR and ELISA experiment revealed positive regulation of cytokines (Arg-1, IL-6, IL-8, IL-10, bFGF, HGF, VEGF, TLR-1, and CXCL13) expression regarding macrophage phenotype transformation and anti-inflammatory performance both inside the microsphere and in the microenvironment of established in vitro inflammatory model. Additionally, positive tendency of cytokine expression benefit wound healing was more pronounced in a fabricated 3D paracrine system than that of a 2D paracrine system. Furthermore, the 3D paracrine system exhibited more efficiently in the wound healing rate compared to the 2D paracrine system in an in vitro model. These results suggested the current paracrine system could be potentially used as a robust wound healing dressing.


Assuntos
Gelatina , Hidrogéis , Hidrogéis/farmacologia , Gelatina/farmacologia , Alginatos/farmacologia , Cicatrização , Citocinas/metabolismo
5.
Langmuir ; 38(33): 10331-10337, 2022 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-35968656

RESUMO

By introducing a heteroatom into carbon material, an effective improvement in capacitance can be realized owing to surface oxidation and reduction reactions of pseudocapacitors. Herein, a simple one-pot carbonization activation method was proposed to convert potassium citrate into three-dimensional interconnected porous carbon (PC). Then, an effective double heteroatom doping method by thiourea was used to prepare nitrogen-sulfur-doped PC (N,S-PC). This porous structure facilitates the storage of a large number of ions and reduces their diffusion path. The synthesized N,S-PC nanomaterial has a capacitance of 674 F/g at 1 A/g in a 1 M H2SO4 electrolyte, can retain 94.41% of the initial capacitance after 10 000 cycles at 5 A/g, and has a long cycle life. More importantly, a symmetric supercapacitor assembled with this material can exhibit an energy density of up to 32.6 (W·h)/kg at a high-power density of 750 W/kg. This is due to the high performance of N,S-PC in supercapacitor electrode materials.

6.
Nanotechnology ; 33(40)2022 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-35617936

RESUMO

Flexible force sensors are of great interest in the fields of healthcare, physiological signals, and aircraft smart skin applications because of their compatibility with curved surfaces. However, the simultaneous detection of multidirectional forces remains an engineering challenge, despite the great progress made in recent years. Herein, we present the development of a flexible capacitive force sensor capable of efficiently distinguishing normal and sliding shear forces. A two-layer electrospun polyimide/graphene oxide (PI/GO) nanofiber membrane is used as the dielectric layer, which is sandwiched between one top electrode and four symmetrically distributed bottom electrodes. This composite membrane has an improved dielectric constant, a reduced friction coefficient, and good compressibility, leading to superior performance that includes high sensitivity over a wide operational range with measured results of 3 MPa-1for 0-242 kPa (0-2.2 N) and 0.92 MPa-1for 242-550 kPa (2.2-5 N) in the normal direction; and better than 1 N-1for 0-3 N in thex- andy-axis directions. The system also has a low detection limit of 10 Pa, fast response and recovery times of 39 ms and 13 ms, respectively, a good cyclic stability of 10,000 cycles at a pressure of 176 kPa, and promising potential for use in high-temperature environments (200 °C). Moreover, a prototype 4 × 4 sensor array has been fabricated and successfully used in a robotic system to grasp objects and operate a wireless toy car. As such, the proposed system could offer superior capabilities in simultaneous multidirectional force sensing for applications such as intelligent robots, human-machine interaction, and smart skin.


Assuntos
Grafite , Nanofibras , Humanos , Fenômenos Mecânicos , Tato
7.
BMC Emerg Med ; 22(1): 124, 2022 07 09.
Artigo em Inglês | MEDLINE | ID: mdl-35810275

RESUMO

BACKGROUND: Regurgitation is a complication common during cardiopulmonary resuscitation (CPR). This manikin study evaluated the effect of regurgitation during endotracheal intubation on CPR quality. METHODS: An airway-CPR manikin was modified to regurgitate simulated gastric contents into the oropharynx during chest compression during CPR. In total, 54 emergency medical technician-paramedics were assigned to either an oropharyngeal regurgitation or clean airway scenario and then switched to the other scenario after finishing the first. The primary outcomes were CPR quality metrics, including chest compression fraction (CCF), chest compression depth, chest compression rate, and longest interruption time. The secondary outcomes were intubation success rate and intubation time. RESULTS: During the first CPR-intubation sequence, the oropharyngeal regurgitation scenario was associated with a significantly lower CCF (79.6% vs. 85.1%, P < 0.001), compression depth (5.2 vs. 5.4 cm, P < 0.001), and first-pass success rate (35.2% vs. 79.6%, P < 0.001) and greater longest interruption duration (4.0 vs. 3.0 s, P < 0.001) than the clean airway scenario. During the second and third sequences, no significant difference was observed in the CPR quality metrics between the two scenarios. In the oropharyngeal regurgitation scenario, successful intubation was independently and significantly associated with compression depth (hazard ratio = 0.47, 95% confidence interval, 0.24-0.91), whereas none of the CPR quality metrics were related to successful intubation in the clean airway scenario. CONCLUSION: Regurgitation during endotracheal intubation significantly reduces CPR quality. TRIAL REGISTRATION: ClinicalTrials.gov, NCT05278923 , March 14, 2022.


Assuntos
Reanimação Cardiopulmonar , Manequins , Estudos Cross-Over , Humanos , Intubação Intratraqueal/efeitos adversos , Fatores de Tempo , Vômito
8.
Molecules ; 27(20)2022 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-36296510

RESUMO

Diphenylguanidine (DPG) is a widely used secondary accelerator for the vulcanization of natural rubber (NR) latex. However, its low water solubility and high toxicity limit its use in high-end NR products. In this study, a water-soluble inclusion complex of DPG and a ß-cyclodextrin polymer (ß-CDP), termed DPG-ß-CDP, was prepared through supramolecular interactions and characterized using Fourier-transform infrared spectroscopy, 1H NMR, scanning electron microscopy, and UV-vis spectroscopy techniques. In comparison with that of DPG, the water solubility of DPG-ß-CDP was greatly enhanced because of the water-soluble host molecule. The molar ratio of DPG to the CD unit in ß-CDP was determined to be 1:1. At 25 °C, the binding constant of DPG-ß-CDP was found to be 9.2 × 105 L/mol by UV-vis spectroscopy. The proposed method for forming inclusion complexes with high potential for use as water-soluble vulcanization accelerators is promising.


Assuntos
Borracha , Água , Varredura Diferencial de Calorimetria , Látex , Polímeros/química , Solubilidade , Espectroscopia de Infravermelho com Transformada de Fourier , Água/química , Difração de Raios X
9.
Entropy (Basel) ; 24(9)2022 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-36141058

RESUMO

The publication of trajectory data provides critical information for various location-based services, and it is critical to publish trajectory data safely while ensuring its availability. Differential privacy is a promising privacy protection technology for publishing trajectory data securely. Most of the existing trajectory privacy protection schemes do not take into account the user's preference for location and the influence of semantic location. Besides, differential privacy for trajectory protection still has the problem of balance between the privacy budget and service quality. In this paper, a semantics- and prediction-based differential privacy protection scheme for trajectory data is proposed. Firstly, trajectory data are transformed into a prefix tree structure to ensure that they satisfy differential privacy. Secondly, considering the influence of semantic location on trajectory, semantic sensitivity combined with location check-in frequency is used to calculate the sensitivity of each position in the trajectory. The privacy level of the position is classified by setting thresholds. Moreover, the corresponding privacy budget is allocated according to the location privacy level. Finally, a Markov chain is used to predict the attack probability of each position in the trajectory. On this basis, the allocation of the privacy budget is further adjusted and its utilization rate is improved. Thus, the problem of the balance between the privacy budget and service quality is solved. Experimental results show that the proposed scheme is able to ensure data availability while protecting data privacy.

10.
Sensors (Basel) ; 21(6)2021 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-33809307

RESUMO

Recent years have seen the wide application of Location-Based Services (LBSs) in our daily life. Although users can enjoy many conveniences from the LBSs, they may lose their trajectory privacy when their location data are collected. Therefore, it is urgent to protect the user's trajectory privacy while providing high quality services. Trajectory k-anonymity is one of the most important technologies to protect the user's trajectory privacy. However, the user's attributes are rarely considered when constructing the k-anonymity set. It results in that the user's trajectories are especially vulnerable. To solve the problem, in this paper, a Spatiotemporal Mobility (SM) measurement is defined for calculating the relationship between the user's attributes and the anonymity set. Furthermore, a trajectory graph is designed to model the relationship between trajectories. Based on the user's attributes and the trajectory graph, the SM based trajectory privacy-preserving algorithm (MTPPA) is proposed. The optimal k-anonymity set is obtained by the simulated annealing algorithm. The experimental results show that the privacy disclosure probability of the anonymity set obtained by MTPPA is about 40% lower than those obtained by the existing algorithms while the same quality of services can be provided.

11.
Zhongguo Yi Xue Ke Xue Yuan Xue Bao ; 43(6): 879-885, 2021 Dec 30.
Artigo em Zh | MEDLINE | ID: mdl-34980326

RESUMO

Objective To study the correlation of B-type natriuretic peptide(BNP)level with hemodynamic parameters and inflammatory cytokines in patients with Gram-negative sepsis,and further determine the main factors for the significant increase of BNP level. Methods The prospective study method was applied,and septic patients infected with Gram-negative bacteria from May 2017 to October 2019 were enrolled.The patients were divided into the BNP<2400 ng/L group and the BNP≥2400 ng/L group by taking the average value of BNP as the dividing point.The independent predictors of BNP≥2400 ng/L were analyzed by Logistic regression.Pearson correlation analysis was used to analyze the correlation between BNP and various indicators. Results A total of 106 patients with Gram-negative sepsis were included,among which 60 cases present with higher serum BNP levels than the average of(2398.45 ± 421.45)ng/L.Thus BNP≥2400 ng/L was considered as a significantly increased BNP level.Multiple logistic regression analysis showed that cardiac index(CI)[odds ratio (OR)=0.428,95% confidence interval (95%CI)=0.743-0.965,P=0.011],left ventricular ejection fraction(LVEF) (OR=0.394,95%CI=0.182-0.549,P=0.013),lactic acid (OR=1.983,95%CI=1.264-3.420,P=0.023),endotoxin (OR=6.146,95%CI=4.091-8.226,P=0.001),procalcitonin(PCT) (OR=6.513,95%CI=4.365-8.210,P=0.005) and cardiac troponin I(cTnI) (OR=1.144,95%CI=1.001-2.150,P=0.047) were independent predictors of BNP≥2400 ng/L in patients with Gram-negative sepsis.Pearson correlation analysis showed that BNP was negatively correlated with CI(R=-0.514,P<0.001)and LVEF (R=-0.552,P<0.001),whereas positively correlated with lactic acid (R=0.265,P=0.032),cTnI (R=0.204, P=0.036),PCT(R=0.801,P<0.001),and endotoxin(R=0.765,P<0.001). Conclusions In septic patients with Gram-negative bacterial infection,LVEF,CI,lactic acid,cTnI,endotoxin and PCT are all independent risk factors for the significant increase of BNP,and endotoxin and PCT were more significantly correlated with BNP increase.Endotoxin and inflammatory reaction may be the more important stimulators of BNP increase in septic patients with Gram-negative bacterial infection.


Assuntos
Infecções por Bactérias Gram-Negativas , Sepse , Citocinas , Hemodinâmica , Humanos , Peptídeo Natriurético Encefálico , Prognóstico , Estudos Prospectivos , Volume Sistólico , Função Ventricular Esquerda
12.
Analyst ; 145(15): 5226-5231, 2020 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-32597917

RESUMO

The current clinical protocol to conduct a bacterial antibiotic susceptibility test (AST) requires at least 18 hours, and cannot be accomplished during a single visit for patients. Here, a new method based on the technique of CRISPR-Cas12a is utilized to accomplish a bacterial genotypic AST within one hour with good accuracy. Two amplification approaches are employed and compared: (1) enriching the bacterial concentration by culturing in growth media; and (2) amplifying target DNA from raw samples by recombinase polymerase amplification (RPA). The results show that CRISPR combined with RPA can rapidly and accurately provide a bacterial genotypic AST of urine samples with urinary tract infections for precise antibiotic treatment. As such, this technology could open a new class of rapid bacterial genotypic AST for various infectious diseases.


Assuntos
Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Infecções Urinárias , Antibacterianos/farmacologia , Bactérias/genética , Sistemas CRISPR-Cas/genética , Humanos , Infecções Urinárias/diagnóstico , Infecções Urinárias/tratamento farmacológico
13.
Small ; 15(2): e1804337, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30506848

RESUMO

The intensity ratio of the 2D band to the G band, I2D /IG , is a good criterion in selecting high quality monolayer graphene samples; however, the evaluation of the ultimate value of I2D /IG for intrinsic monolayer graphene is a challenging yet interesting issue. Here, an interesting tension-induced Raman enhancement phenomenon is reported in supported graphene membranes, which show a transition from the corrugated state to the stretched state in the vicinity of wells. The I2D /IG of substrate-supported graphene membranes near wells are significantly enhanced up to 16.74, which is the highest experimental value to the best of knowledge, increasing by more than 600% when the testing points approach the well edges.The macroscopic origin of this phenomenon is that corrugated graphene membranes are stretched by built-in tensions. A lattice dynamic model is proposed to successfully reveal the microscopic mechanism of this phenomenon. The theoretical results agree well with the experimental data, demonstrating that tensile stresses can depress the amplitude of in-plane vibration of sp2 -bonded carbon atoms and result in the decrease in the G band intensity. This work can be helpful in furthering the development of the method of suppressing small ripples in graphene and acquiring ultraflat 2D materials.

14.
J Nanosci Nanotechnol ; 19(8): 5310-5316, 2019 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-30913849

RESUMO

Flexible humidity sensors play important roles in wearable devices and consuming electronics which provide a convenient way between digital and physical worlds. This work presents an easy fabricated method for flexible humidity sensors all based on carbon material including electrodes and functional layers. The interdigital electrodes are made by direct laser writing on commercial Kapton tapes and the transferring to flexible Polydimethylsiloxane (PDMS) substrates. The humidity sensing material is reduced graphene oxide (rGO) in nanometer thickness by electrospray. The rGO flakes covered the micro-size laser induced graphite (LIG), forming rGO-graphite balls, dramatically increase surface areas to interact with water molecules. The results show high precision sensitivity and fast response time for adsorption (0.9 s) and desorption (4.5 s). This method provides a novel method for fabricating cost-effective flexible humidity sensors.

15.
BMC Anesthesiol ; 19(1): 8, 2019 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-30630425

RESUMO

BACKGROUND: The Cormack-Lehane (C-L) grade III airway is considered to be a challenging airway to intubate and is associated with a poor intubation success rate. The purpose of this study was to investigate whether the holding position, shapes, bend angles of the endotracheal tube (ET) and the stylet-assisted lifting of the epiglottis could improve the success rate of intubation. METHODS: Thirty-two participants, 26 physicians, 2 residents, and 4 nurse practitioners, with 12.09 ± 5.38 years of work experience in the emergency department and more than 150 annual intubation events, were enrolled in this randomized, cross-over mannequin study. We investigated the effects of straight-to-cuff ET shapes with 35° and 50° bend angles, banana-shaped ET with longitudinal distances of 28 cm and 26 cm, two methods of holding the ET (either on the top or in the middle), and lifting or not the epiglottis, on the intubation duration, its success rate, and its subjective difficulty. The aim of the study is to provide optimized intubation strategies for difficult airway with C-L IIb or III grades, when the inlet of the trachea cannot be visualized. RESULTS: The two groups that lifted the epiglottis using the stylets, in bend angles of 35° and 50°, had the shortest duration of intubation (23.75 ± 14.24 s and 20.72 ± 6.90 s, hazard ratios 1.54 and 1.85 with 95% confidence intervals [95% CI] of 1.01-2.34 and 1.23-2.78, respectively) and a 100% success rate in intubations. In the survival analysis, lifting of the epiglottis was the only significant factor (p < 0.0001, 95% CI 1.34-2.11) associated with the success rate of intubation. CONCLUSIONS: The use of the epiglottic lift as an adjunctive technique can facilitate the intubation and improve its success rate without increasing procedure difficulty, in C-L III airway, when only the epiglottis is seen. TRIAL REGISTRATION: ClinicalTrials Registry ( https://clincaltrials.gov , identifier NCT03366311).


Assuntos
Epiglote , Intubação Intratraqueal/métodos , Traqueia , Adulto , Estudos Cross-Over , Serviço Hospitalar de Emergência , Desenho de Equipamento , Feminino , Humanos , Masculino , Manequins
16.
Mikrochim Acta ; 186(7): 418, 2019 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-31187269

RESUMO

Two kinds of flexible ozone (O3) sensors were obtained by placing pristine ZnO nanorods and gold-modified ZnO nanorods (NRs) on a bi-axially oriented poly(ethylene terephthalate) substrate. The chemiresistive sensor is operated at typically 1 V at room temperature under the UV-light illumination. The ZnO nanorods were prepared via a hydrothermal route and have a highly crystalline wurtzite structure, with diameters ranging between 70 and 300 nm and a length varying from 1 to 3 µm. The ZnO NRs were then coated with a ca. 10 nm gold layer whose presence was confirmed with microscopy analysis. This sensor is found to be superior to detect ozone at a room temperature. Typical figures of merit include (a) a sensor response of 108 at 30 ppb ozone for gold-modified ZnO NRs, and (b) a linear range that extends from 30 to 570 ppb. The sensor is stable, reproducible and selective for O3 compared to other oxidizing and reducing gases. The enhanced performance induced by the modification of ZnO nanorods with thin layer of gold is attributed to the increased reaction kinetics compared to pristine ZnO NRs. The sensing mechanism is assumed to be based on the formation of a nano-Schottky type barrier junction at the interface between gold and ZnO. Graphical abstract Room temperature, flexible UV-enhanced gold modified ZnO nanorods can detect ppb levels of ozone.

17.
Macromol Rapid Commun ; 39(14): e1800102, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29786920

RESUMO

The formulation of optoelectronic components into 1D nanostructures allows the promotion of new materials with multifunctionalities. In this work, it is demonstrated that new synthesis of photocatalytic carbon nanofiber decorated with semi-embedded titanium oxide (TiO2 ), namely, TiO2 @carbon fiber, is conveniently accessed through the electrospinning of polyacrylonitrile polymer and TiO2 particle comixture, and then followed by photon-activated self-erosion to expose the embedded TiO2 and carbonization. The hybrid nanofibers are characterized by field emission scanning electron microscopy, transmission electron microscopy, and X-ray diffraction analysis. Furthermore, the photocatalytic activities of the resultant fibers are tested with photodegradation of Rhodamine B in aqueous solution, which reveals that the carbon nanofiber with semi-embedded TiO2 drastically improved catalytic efficiency and recyclability, comparing to those fibers without or with embedded TiO2 .


Assuntos
Catálise , Fotólise , Rodaminas/química , Titânio/química , Resinas Acrílicas/química , Adsorção , Carbono/química , Fibra de Carbono , Nanofibras/química
18.
J Nanosci Nanotechnol ; 18(1): 156-164, 2018 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-29768827

RESUMO

This paper describes the application of piezoelectric fibers and films formed using near-field electrospinning (NFES) and electrospray (ESP) technology. Poly(γ-methyl L-glutamate) (PMLG), a biocompatible material, was mixed with poly(ethylene oxide) (PEO) and surfactant to obtain a solution of appropriate viscosity and conductance. Because the orientation of the dipoles in PMLG was enhanced upon applying an electric field, we could use the NFES and ESP processes to align dipoles and enhance the piezoelectric properties of the resulting fibrous materials. The maximum peak voltage of a fiber-based harvester prepared using this approach was 0.056 V. Because the fibers and films were non-toxic biological materials displaying excellent piezoelectric characteristics, we deposited them on glass substrates coated with indium tin oxide to observe their effects on the proliferation of cells. The negative charge of PMLG decreased the proliferation of mouse fibroblast cells (NIH3T3); indeed, decreasing the interspacing between the fibers slightly decreased the proliferation of these cells. Moreover, the migration of the cells was inhibited significantly, or even halted, when the coverage of the ESP films increased, implying a growth inhibition effect.

19.
Proc Natl Acad Sci U S A ; 112(21): 6533-8, 2015 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-25971729

RESUMO

With the availability of nanoparticles with controlled size and shape, there has been renewed interest in the mechanical properties of polymer/nanoparticle blends. Despite the large number of theoretical studies, the effect of branching for nanofillers tens of nanometers in size on the elastic stiffness of these composite materials has received limited attention. Here, we examine the Young's modulus of nanocomposites based on a common block copolymer (BCP) blended with linear nanorods and nanoscale tetrapod Quantum Dots (tQDs), in electrospun fibers and thin films. We use a phenomenological lattice spring model (LSM) as a guide in understanding the changes in the Young's modulus of such composites as a function of filler shape. Reasonable agreement is achieved between the LSM and the experimental results for both nanoparticle shapes--with only a few key physical assumptions in both films and fibers--providing insight into the design of new nanocomposites and assisting in the development of a qualitative mechanistic understanding of their properties. The tQDs impart the greatest improvements, enhancing the Young's modulus by a factor of 2.5 at 20 wt.%. This is 1.5 times higher than identical composites containing nanorods. An unexpected finding from the simulations is that both the orientation of the nanoscale filler and the orientation of X-type covalent bonds at the nanoparticle-ligand interface are important for optimizing the mechanical properties of the nanocomposites. The tQD provides an orientational optimization of the interfacial and filler bonds arising from its three-dimensional branched shape unseen before in nanocomposites with inorganic nanofillers.

20.
BMC Complement Altern Med ; 18(1): 96, 2018 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-29554903

RESUMO

BACKGROUND: No animal model studies have been conducted in which the efficacy of herbal compounds has been tested against multidrug-resistant Acinetobacter baumannii infections. Very few antibiotics are available for the treatment of pulmonary infections caused by extensively drug-resistant Acinetobacter baumannii (XDRAB). To find alternative treatments, traditional Chinese herbs were screened for their antimicrobial potential. METHODS: The present study screened 30 herbs that are traditionally used in Taiwan and that are commonly prescribed for heat clearing and detoxification. The herbs with antibacterial activities were analysed by disc diffusion assays, time-kill assays and a murine lung infection model. RESULTS: Of the 30 herbs tested, only Scutellaria barbata demonstrated 100% in vitro activity against XDRAB. Furthermore, we compared the antibacterial effect of the S. barbata extract with that of colistin, and the S. barbata extract showed better antibacterial effect. In the XDRAB pneumonia murine model, we compared the antimicrobial effects of the orally administered S. barbata extract (200 mg/kg, every 24 h), the intratracheally administered colistin (75,000 U/kg, every 12 h), and the control group. The bacterial load in the lungs of the treatment group that received the oral S. barbata extract showed a significant decrease in comparison to that in the lungs of the control group. In addition, histopathological examinations also revealed better resolution of perivascular, peribronchial, and alveolar inflammation in the oral S. barbata extract-treated group. CONCLUSIONS: Our in vitro and in vivo data from the animal model support the use of S. barbata as an alternate drug to treat XDRAB pulmonary infections. However, detailed animal studies and clinical trials are necessary to establish the clinical utility of S. barbata in treating XDRAB pulmonary infections.


Assuntos
Infecções por Acinetobacter/tratamento farmacológico , Acinetobacter baumannii/efeitos dos fármacos , Antibacterianos/administração & dosagem , Farmacorresistência Bacteriana , Pneumopatias/tratamento farmacológico , Extratos Vegetais/administração & dosagem , Scutellaria/química , Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/fisiologia , Animais , Antibacterianos/química , Carga Bacteriana/efeitos dos fármacos , Colistina/administração & dosagem , Feminino , Humanos , Pneumopatias/microbiologia , Camundongos , Camundongos Endogâmicos BALB C , Testes de Sensibilidade Microbiana , Extratos Vegetais/química , Taiwan
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