SOME COMMON FIXED POINT RESULTS FOR RATIONAL CONTRACTION TYPE VIA THE C-CLASS FUNCTIONS ON METRIC SPACES

The purpose of this paper is to prove some common fixed point results for rational contraction type via the C-class functions on metric spaces. As an application, we study the existence of solutions to the system of nonlinear integral equations

Multifactorial Evolutionary Algorithm For Clustered Minimum Routing Cost Problem

Minimum Routing Cost Clustered Tree Problem (CluMRCT) is applied in various fields in both theory and application. Because the CluMRCT is NP-Hard, the approximate approaches are suitable to find the solution for this problem. Recently, Multifactorial Evolutionary Algorithm (MFEA) has emerged as one of the most efficient approximation algorithms to deal with many different kinds of problems. Therefore, this paper studies to apply MFEA for solving CluMRCT problems. In the proposed MFEA, we focus on crossover and mutation operators which create a valid solution of CluMRCT problem in two levels: first level constructs spanning trees for graphs in clusters while the second level builds a spanning tree for connecting among clusters. To reduce the consuming resources, we will also introduce a new method of calculating the cost of CluMRCT solution. The proposed algorithm is experimented on numerous types of datasets. The experimental results demonstrate the effectiveness of the proposed algorithm, partially on large instance

In vitro antioxidant activity and content of bioactive compounds from Homalomena occulta

Homalomena occulta, a plant widely used in traditional Vietnamese medicine, was assessed for its antioxidant potential through DPPH radical scavenging and total antioxidant capacity methods. The results showed that Homalomena occulta exhibited significant antioxidant activities with a low IC50 value of 40.27 μg/mL, which is comparable to that of curcumin (38.50 μg/mL). Furthermore, the total antioxidant capacity of the Homalomena occulta extract was determined to be 77.48 ± 2.34 mg GA/g. To investigate the composition of the plant, various compounds including total phenolic, total flavonoid, polysaccharides, and triterpenoids were quantified using colorimetric methods with specific reagents. The content of phenolic compounds, flavonoid compounds, polysaccharides, and triterpenoids in Homalomena occulta was found to be 36.87 ± 0.42 GAE/g, 26.83 ± 0.29 mg QUE/g, 5.06 ± 0.06%, and 52.09 ± 1.77 mg Olenanoic/g, respectively. Notably, this study provides the first-ever report on the polysaccharide and total triterpenoid content of Homalomena occulta

TiO2 Nanowires on TiO2 Nanotubes Arrays (TNWs/TNAs) Decorated with Au Nanoparticles and Au Nanorods for Efficient Photoelectrochemical Water Splitting and Photocatalytic Degradation of Methylene Blue

In this study, TiO2 nanowires on TiO2 nanotubes arrays (TNWs/TNAs) and Au-decorated TNWs/TNAs nanostructures are designed and fabricated as a new type of photoanode for photoelectrochemical (PEC) water splitting. The TNWs/TNAs were fabricated on Ti folds by anodization using an aqueous NH4F/ethylene glycol solution, while Au nanoparticles (NPs) and Au nanorods (NRs) were synthesized by Turkevich methods. We studied the crystal structure, morphology, and PEC activity of four types of nanomaterial photoanodes, including TNWs/TNAs, Au NPs- TNWs/TNAs, Au NRs-TNWs/TNAs, and Au NPs-NRs-TNWs/TNAs. The TiO2 and Au-TiO2 samples exhibited pure anatase phase of TiO2 with (0 0 4), (1 0 1), and (1 0 5) preferred orientations, while Au-TiO2 presented a tiny XRD peak of Au (111) due to a small Au decorated content of 0.7 ± 0.2 at.%. In addition, the samples obtained a well-defined and uniformed structure of TNAs/TNWs; Au NPs (size of 19.0 ± 1.9 nm) and Au NRs (width of 14.8 ± 1.3 nm and length of 99.8 ± 15.1 nm) were primarily deposited on TNWs top layer; sharp Au/TiO2 interfaces were observed from HRTEM images. The photocurrent density (J) of the photoanode nanomaterials was in the range of 0.24–0.4 mA/cm2. Specifically, Au NPs-NRs- decorated TNWs/TNAs attained the highest J value of 0.4 mA/cm2 because the decoration of Au NPs and Au NRs mixture onto TNWs/TNAs improved the light harvesting capability and the light absorption in the visible-infrared region, enhanced photogenerated carriers’ density, and increased electrons’ injection efficiency via the localized surface plasmon resonance (LSPR) effect occurring at the Au nanostructures. Furthermore, amongst the investigated nanophotocatalysts, the Au NPs-NRs TNWs/TNAs exhibited the highest photocatalytic activity in the degradation of methylene blue with a high reaction rate constant of 0.7 ± 0.07 h−1, which was 2.5 times higher than that of the pristine TNWs/TNAs

Facile Preparation Method of TiO₂/Activated Carbon for Photocatalytic Degradation of Methylene Blue

The development of nanocomposite photocatalysts with high photocatalytic activity, cost-effectiveness, a simple preparation process, and scalability for practical applications is of great interest. In this study, nanocomposites of TiO2 Degussa P25 nanoparticles/activated carbon (TiO2/AC) were prepared at various mass ratios of (4:1), (3:2), (2:3), and (1:4) by a facile process involving manual mechanical pounding, ultrasonic-assisted mixing in an ethanol solution, paper filtration, and mild thermal annealing. The characterization methods included XRD, SEM-EDS, Raman, FTIR, XPS, and UV-Vis spectroscopies. The effects of TiO2/AC mass ratios on the structural, morphological, and photocatalytic properties were systematically studied in comparison with bare TiO2 and bare AC. TiO2 nanoparticles exhibited dominant anatase and minor rutile phases and a crystallite size of approximately 21 nm, while AC had XRD peaks of graphite and carbon and a crystallite size of 49 nm. The composites exhibited tight decoration of TiO2 nanoparticles on micron-/submicron AC particles, and uniform TiO2/AC composites were obtained, as evidenced by the uniform distribution of Ti, O, and C in an EDS mapping. Moreover, Raman spectra show the typical vibration modes of anatase TiO2 (e.g., E1g(1), B1g(1), Eg(3)) and carbon materials with D and G bands. The TiO2/AC with (4:1), (3:2), and (2:3) possessed higher reaction rate constants (k) in photocatalytic degradation of methylene blue (MB) than that of either TiO2 or AC. Among the investigated materials, TiO2/AC = 4:1 achieved the highest photocatalytic activity with a high k of 55.2 × 10−3 min−1 and an MB removal efficiency of 96.6% after 30 min of treatment under UV-Vis irradiation (120 mW/cm2). The enhanced photocatalytic activity for TiO2/AC is due to the synergistic effect of the high adsorption capability of AC and the high photocatalytic activity of TiO2. Furthermore, TiO2/AC promotes the separation of photoexcited electron/hole (e−/h+) pairs to reduce their recombination rate and thus enhance photocatalytic activity. The optimal TiO2/AC composite with a mass ratio of 4/1 is suggested for treating industrial or household wastewater with organic pollutants

Genomic characterization of endemic diarrheagenic Escherichia coli and Escherichia albertii from infants with diarrhea in Vietnam.

BackgroundDiarrheagenic Escherichia coli (DEC) is a group of bacterial pathogens that causes life-threatening diarrhea in children in developing countries. However, there is limited information on the characteristics of DEC isolated from patients in these countries. A detailed genomic analysis of 61 DEC-like isolates from infants with diarrhea was performed to clarify and share the characteristics of DEC prevalent in Vietnam.Principal findingsDEC was classified into 57 strains, including 33 enteroaggregative E. coli (EAEC) (54.1%), 20 enteropathogenic E. coli (EPEC) (32.8%), two enteroinvasive E. coli (EIEC) (3.3%), one enterotoxigenic E. coli (ETEC), and one ETEC/EIEC hybrid (1.6% each), and surprisingly into four Escherichia albertii strains (6.6%). Furthermore, several epidemic DEC clones showed an uncommon combination of pathotypes and serotypes, such as EAEC Og130:Hg27, EAEC OgGp9:Hg18, EAEC OgX13:H27, EPEC OgGp7:Hg16, and E. albertii EAOg1:HgUT. Genomic analysis also revealed the presence of various genes and mutations associated with antibiotic resistance in many isolates. Strains that demonstrate potential resistance to ciprofloxacin and ceftriaxone, drugs recommended for treating childhood diarrhea, accounted for 65.6% and 41%, respectively.SignificanceOur finding indicate that the routine use of these antibiotics has selected resistant DECs, resulting in a situation where these drugs do not provide in therapeutic effects for some patients. Bridging this gap requires continuous investigations and information sharing regarding the type and distribution of endemic DEC and E. albertii and their antibiotic resistance in different countries