In this study, the effect of coated hydrogel layer on characteristics of the whole gelatin/silver nanoparticles multi‐coated polycaprolactone membrane (PCLGelAg) was investigated through systematic ...and typical wound dressing characterizations to select the optimal number of layers for practical applications. Scanning electron microscopy, free swell absorptive capacity and tensile test in both wet and dry conditions were conducted to characterize all fabricated membranes of six coating times. In vitro cytotoxicity and agar diffusion evaluation were also carried out to assess the biocompatibility and antibacterial activity of the membranes. The findings illustrated that as the coated layers increase, the absorptive capacity, and degradation rate were higher, the membranes were stiffer in dry state while the tensile strength in wet state, elongation, and cell viability were significantly decreased. PCLGelAg3 was chosen to be the best fit for wound healing since it maintained quite sufficient maximum buffer uptake, elasticity, cell viability along with inducing abnormalities in bacterial morphology and preventing biofilm formation.
Abstract
Background
Little is known about the natural history of asymptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.
Methods
We conducted a prospective study at a ...quarantine center for coronavirus disease 2019 in Ho Chi Minh City, Vietnam. We enrolled quarantined people with reverse-transcription polymerase chain reaction (RT-PCR)–confirmed SARS-CoV-2 infection, collecting clinical data, travel and contact history, and saliva at enrollment and daily nasopharyngeal/throat swabs (NTSs) for RT-PCR testing. We compared the natural history and transmission potential of asymptomatic and symptomatic individuals.
Results
Between 10 March and 4 April 2020, 14 000 quarantined people were tested for SARS-CoV-2; 49 were positive. Of these, 30 participated in the study: 13 (43%) never had symptoms and 17 (57%) were symptomatic. Seventeen (57%) participants imported cases. Compared with symptomatic individuals, asymptomatic people were less likely to have detectable SARS-CoV-2 in NTS collected at enrollment (8/13 62% vs 17/17 100%; P = .02). SARS-CoV-2 RNA was detected in 20 of 27 (74%) available saliva samples (7 of 11 64% in the asymptomatic group and 13 of 16 81% in the symptomatic group; P = .56). Analysis of RT-PCR positivity probability showed that asymptomatic participants had faster viral clearance than symptomatic participants (P < .001 for difference over the first 19 days). This difference was most pronounced during the first week of follow-up. Two of the asymptomatic individuals appeared to transmit SARS-CoV-2 to 4 contacts.
Conclusions
Asymptomatic SARS-CoV-2 infection is common and can be detected by analysis of saliva or NTSs. The NTS viral loads fall faster in asymptomatic individuals, but these individuals appear able to transmit the virus to others.
Forty-three percent (13/30) of confirmed SARS-CoV-2–infected individuals were asymptomatic, with the virus detected in both saliva and nasopharyngeal/throat swabs. Viral clearance was faster in asymptomatic individuals, but they still appeared able to pass the infection to others.
Novel ternary composites of polyaniline (PANI), reduced graphene oxide (RGO), and cellulose nanofibers (CNFs) are prepared by a chemical method for hybrid supercapacitors. CNFs were extracted from ...sugarcane bagasse waste in sugar production, by physicochemical processes. The composites were investigated as electrode-active materials for hybrid supercapacitors. The obtained results revealed that the presence of RGO and CNFs in the composites led to enhanced electrochemical performances, such as capacitance, rate capability, and long-term cyclability of the composite. The optimal composite of CNFs/RGO/PANI with a weight ratio of 4/16/80 can deliver the highest specific capacitance at 566.2 F g
1
under an applied current of 1 A g
1
. After 1000 cycles of repetitive charge and discharge, the optimal composite retains 85.4% of its initial capacitance, whereas the PANI electrode obtained only 36.7% under the same conditions. Moreover, the supercapacitive performance is also strongly dependent on the component of the ternary composites. Overall, the composite is a promising material for hybrid supercapacitors; and the CNF component is a renewable material and a product of waste materials.
Ternary biocomposites of nanocellulose, reduce graphene oxide and polyaniline.
Purpose: In the context of the emergence of industry 4.0, using mobile phones as a modern distribution channel to execute financial services is a significant solution for commercial banks' retail ...services and a gateway to promote financial inclusion and market development. Despite that service quality and customer satisfaction are two diverse notions and closely related to each other in the service sector, there is hardly a research which empirically examines the impacts of each dimensions of mobile banking service quality and customer satisfaction. Research design, data and methodology: This study first employs in-depth interview to explore various aspects of mobile banking service quality dimensions, including empathy, responsiveness, tangibility, assurance, and reliability that serves to develop measurement scales and hypothesis development. A quantitative survey is followed to collect data from 265 Vietnamese bank customers to empirically test the conceptual model. Resutls: Our findings indicate that more human-related factors including empathy, assurance, and responsiveness show the strongest impacts on customer satisfaction with mobile banking service while tangibility and reliability, as technical aspects, are less influential factors. Conclusions: Finally, some crucial implications are drawn for the banks to manage consumer behavior in mobile banking.
Purpose: In the context of the emergence of industry 4.0, using mobile phones as a modern distribution channel to execute financial services is a significant solution for commercial banks' retail ...services and a gateway to promote financial inclusion and market development. Despite that service quality and customer satisfaction are two diverse notions and closely related to each other in the service sector, there is hardly a research which empirically examines the impacts of each dimensions of mobile banking service quality and customer satisfaction. Research design, data and methodology: This study first employs in-depth interview to explore various aspects of mobile banking service quality dimensions, including empathy, responsiveness, tangibility, assurance, and reliability that serves to develop measurement scales and hypothesis development. A quantitative survey is followed to collect data from 265 Vietnamese bank customers to empirically test the conceptual model. Results: Our findings indicate that more human-related factors including empathy, assurance, and responsiveness show the strongest impacts on customer satisfaction with mobile banking service while tangibility and reliability, as technical aspects, are less influential factors. Conclusions: Finally, some crucial implications are drawn for the banks to manage consumer behavior in mobile banking. KCI Citation Count: 0
A synergistic multilayer membrane design is necessary to satisfy a multitude of requirements of an ideal wound dressing. In this study, trilayer dressings with asymmetric wettability, composed of ...electrospun polycaprolactone (PCL) base membranes coated with oligomer chitosan (COS) in various concentrations of polyvinylpyrrolidone (PVP), are fabricated for wound dressing application. The membranes are expected to synergize the hygroscopic, antibacterial, hemostatic, and biocompatible properties of PCL and COS. The wound dressing was coated by spraying the solution of 3% COS and 6% PVP on the PCL base membrane (PVP6–3) three times, which shows good interaction with biological subjects, including bacterial strains and blood components. PVP6–3 samples confirm the diameter of inhibition zones of 20.0 ± 2.5 and 17.9 ± 2.5 mm against Pseudomonas aeruginosa and Staphylococcus aureus, respectively. The membrane induces hemostasis with a blood clotting index of 74% after 5 min of contact. In the mice model, wounds treated with PVP6–3 closed 95% of the area after 10 days. Histological study determines the progression of skin regeneration with the construction of granulation tissue, new vascular systems, and hair follicles. Furthermore, the newly-growth skin shares structural resemblances to that of native tissue. This study suggests a simple approach to a multi-purpose wound dressing for clinical treatment.
Biphasic calcium phosphate (BCP) is an ideal bone substitute with controllable bioresorption/biodegradation by changing its relative amount of hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) ...compositions. This study investigated the effect of synthetic conditions on the physicochemical properties and the remineralization behaviors of BCP materials in artificial saliva (AS). BCPs were obtained under the sonochemical condition at pH of 5.0 (BCP_5), 7.0 (BCP_7), and 9.0 (BCP_9), and all were sintered at 800, 1000, and 1200 °C. The HA/β-TCP ratio of BCPs increased according to the pH increase during the synthesis process. BCP_5 sintered at 800 °C with the highest β-TCP contents demonstrated (1) fast neutralization capacity to prevent enamel from dissolving in acidic saliva and (2) remineralization ion supply, and (3) new apatite formation found in acidic AS, indicating its high potential remineralization agent for dental care applications.
Display omitted
•BCPs synthesized at pH 5.0 with high β-TCP had fast neutralization capacity in acidic saliva and ion supply.•BCPs synthesized at pH 5.0 generated new apatite formation in acidic and neutral artificial saliva.•BCPs sintered at 800 and 1000 °C achieved better remineralization properties than 1200 °C.
A carbon-based solid acid catalyst was prepared by incomplete carbonization of Acacia mangium wood sawdust, treated with H
3
PO
4
followed by sulfonation. FT-IR, BET, SEM, EDS and TPD-NH
3
were used ...to characterize the structure and performance of the catalyst. Results showed that the catalyst formed was an amorphous carbon composed of aromatic carbon sheets with -COOH, -OH and -SO
3
H groups. Primary impregnation with H
3
PO
4
could promote formation of mesoporous catalyst. The optimized carbonization temperature and time for the catalyst were 500°C and 30 min. The -SO
3
H density and specific surface area for the catalyst prepared under the optimized conditions were about 2.9-3.2 mmol/g and 740 m
2
/g, respectively. The A. mangium wood sawdust was also used to produce hydroxymethylfurfural, utilizing the prepared solid catalyst. The biomass was pretreated by alkaline solution to obtain the pulp, which was saccharified by Novozymes commercial enzyme and then used for the conversion. The integrated scheme for the preparation of the solid acid catalyst and hydroxymethylfurfural from A. mangium wood is an efficient conversion method of wood biomass into green catalysts and chemicals.
Quantitative yttrium-90 (Y-90) SPECT imaging is challenging due to the nature of Y-90, an almost pure beta emitter that is associated with a continuous spectrum of bremsstrahlung photons that have a ...relatively low yield. This paper proposes joint spectral reconstruction (JSR), a novel bremsstrahlung SPECT reconstruction method that uses multiple narrow acquisition windows with accurate multi-band forward modeling to cover a wide range of the energy spectrum. Theoretical analyses using Fisher information and Monte-Carlo (MC) simulation with a digital phantom show that the proposed JSR model with multiple acquisition windows has better performance in terms of covariance (precision) than previous methods using multi-band forward modeling with a single acquisition window, or using a single-band forward modeling with a single acquisition window. We also propose an energy-window subset (ES) algorithm for JSR to achieve fast empirical convergence and maximum-likelihood based initialization for all reconstruction methods to improve quantification accuracy in early iterations. For both MC simulation with a digital phantom and experimental study with a physical multi-sphere phantom, our proposed JSR-ES, a fast algorithm for JSR with ES, yielded higher recovery coefficients (RCs) on hot spheres over all iterations and sphere sizes than all the other evaluated methods, due to fast empirical convergence. In experimental study, for the smallest hot sphere (diameter 1.6cm), at the 20th iteration the increase in RCs with JSR-ES was 66 and 31% compared with single wide and narrow band forward models, respectively. JSR-ES also yielded lower residual count error (RCE) on a cold sphere over all iterations than other methods for MC simulation with known scatter, but led to greater RCE compared with single narrow band forward model at higher iterations for experimental study when using estimated scatter.
In this study, we proposed a straightforward electrospun polycaprolactone (PCL) loaded with silver nanoparticles (SNPs) membrane fabrication process, in which SNPs were directly synthesized from ...silver nitrate (AgNO
3
) in PCL–acetone mixture by gamma irradiation. The insolubility of AgNO
3
in PCL solution was solved using an auxiliary dimethyl sulfoxide solvent. As a physical approach, gamma rays readily converted silver ions into SNPs without the addition of harmful reduction agents, which reduced the cytotoxicity of the synthesized material. By avoiding some processes such as purification, solvent removal, or redispersion of SNPs, this method was more time-saving compared to other related studies. SNPs formation was confirmed by both UV–Visible spectrum (UV–Vis) and X-ray diffraction analysis. Scanning electron microscopy (SEM) revealed that the addition of SNPs significantly reduced the fiber diameter of PCL–Ag membranes compared to that of raw PCL. Uniform spherical-shaped SNPs incorporated in PCL fibers were observed under transmission electron microscopy (TEM). The tensile test showed that the electrospun PCL–Ag membranes exhibited good mechanical characteristics. Moisture easily penetrated the porous microstructure of PCL–Ag, facilitating wound humidity regulation. Inductively coupled plasma-mass spectroscopy (ICP-MS) was employed to study the release profiles of SNPs at different time intervals. Overall, the PCL–Ag 500 ppm sample exerted excellent antibacterial activity against
Pseudomonas aeruginosa
and
Staphylococcus aureus
strains and low in vitro cytotoxicity.
PDF
