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Co-precipitation method was adopted in the preparation of nickel-cobalt oxides for potential application in supercapacitors. The formation of spinel nickel-cobalt oxide, NiCo2O4 started below 400 °C as confirmed by X-ray diffraction analysis. Pure phase nickel cobaltite with cation ratio of 1:2 (Ni:Co) was obtained at calcination temperature of 400 °C. The spinel phase decomposed gradually until 700 °C. The calcination time for the formation of NiCo2O4 was found to be between 2 to 4 h. The particle size of the prepared sample studied by transmission electron microscopy showed a value of 9.47 nm. The electrochemical properties of the metal oxide were measured in various acidic, neutral and alkaline electrolyte systems (1.0 M HCl, 1.0 M KCl and 1.0 M KOH) by employment of cyclic voltammetry, galvanostatic charge-discharge test and electrochemical impedance spectroscopy. Ideal capacitor behaviour with the largest operating voltage of 1.0 V and good electrochemical stability were observed in NiCo2O4 using neutral KCl aqueous electrolyte. Meanwhile, the prepared sample displayed the highest surface redox activity in 1.0 M KOH alkaline electrolyte but showed the lowest electrochemical performance in acidic electrolyte. At the current density of 0.5 A g−1, 1.0 M HCl, 1.0 M KCl and 1.0 M KOH gave specific capacitance values of 3.8, 41.9 and 249.8 F g−1 respectively. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Precious metal oxides exhibit impressive characteristics that caught worldwide attention due to their promising capacitive performance, excellent electrochemical stability and low resistance, and these metal oxides have been extensively employed in supercapacitor application. This type of supercapacitors is known as redox supercapacitors or pseudocapacitors which applied faradaic process in storing energy in their systems. Thus, new materials with impressive electrochemical performance are highly demanded. In this aspect, cobaltite system with spinel structure has been the subject of intense research due to its established applications in electrochemistry. Besides, carbonaceous materials like activated carbons, carbon nanotubes, graphites, graphenes and fullerenes utilize electric double-layer capacitance whereby energy is stored by charge separation at an electrode/electrolyte interface. With greater development conducted on metal oxides and carbonaceous materials for supercapacitor application, introduction of hybrid and composite electrodes comprise of these two types of materials have been well received. [ABSTRACT FROM AUTHOR]

Abstract: Nanostructured synthesis of nickel–cobalt oxide/activated carbon composite by adapting a co-precipitation protocol was revealed by transmission electron microscopy. X-ray diffraction analysis confirmed that nickel–cobalt oxide spinel phase was maintained in the pure and composite phases. Cyclic voltammetry, galvanostatic charge–discharge tests and ac impedance spectroscopy were employed to elucidate the electrochemical properties of the composite electrodes in 1.0 M KCl. The specific capacitance which was the sum of double-layer capacitance of the activated carbon and pseudocapacitance of the metal oxide increased with the composition of nickel–cobalt oxide before showing a decrement for heavily-loaded electrodes. Utilisation of nickel–cobalt oxide component in the composite with 50 wt. % loading displayed a capacitance value of ∼59 F g−1. The prepared composite electrodes exhibited good electrochemical stability. [Copyright &y& Elsevier]

Abstract: NiCo2O4 and NiMn x Co2−x O4−y (x ≤1.0) have been synthesized by a co-precipitation method, and the effects of Mn substitution for Co on the microstructural and electrochemical properties pertaining to the supercapacitor applications have been studied. Spinel structure is retained when a quarter of Co of the spinel is substituted with Mn (i.e., x =0.5), where the Mn ions predominantly occupy the octahedral sites of the spinel lattice. The presence of Mn significantly suppresses crystal growth upon thermal treatment but tends to cause severe crystallite agglomeration. Electrodes of the materials exhibit nearly ideal electrochemical capacitor behavior in neutral electrolyte solution (1M KCl(aq)). Mn substitution greatly enhances the specific capacitance of the spinel, giving gravimetric and superficial specific capacitances of ca. 110Fg−1 and ca. 380μFcm−2, respectively for x =0.5 powder. The capacitance enhancement is attributed to the facile charge-transfer characteristic of the Mn ions, as revealed by in situ X-ray absorption near-edge structure analysis. [Copyright &y& Elsevier]

There has been a resurgence in the clinical use of polymyxin antibiotics such as colistin due to the limited treatment options for infections caused by carbapenem-resistant Enterobacterales (CRE). However, this last-resort antibiotic is currently confronted with challenges which include the emergence of chromosomal and plasmid-borne colistin resistance. Colistin resistance in Klebsiella pneumoniae is commonly caused by the mutations in the chromosomal gene mgrB. MgrB spans the inner membrane and negatively regulates PhoP phosphorylation, which is essential for bacterial outer membrane lipid biosynthesis. The present review intends to draw attention to the role of mgrB chromosomal mutations in membrane permeability in K. pneumoniae that confer colistin resistance. With growing concern regarding the global emergence of colistin resistance, deciphering physical changes of the resistant membrane mediated by mgrB inactivation may provide new insights for the discovery of novel antimicrobials that are highly effective at membrane penetration, in addition to finding out how this can help in alleviating the resistance situation. [ABSTRACT FROM AUTHOR]

In this study, we engineered a sub-70 nm nanocomposite of ZnO/Zn2TiO4 using a low-temperature solution-phase method with titanium isopropoxide and zinc acetate as precursors, and isopropyl alcohol and water as solvents. The investigation focused on nanocomposite growth by varying precursor and surfactant concentrations and their efficiency within different pH ranges. All three ZnO/Zn2TiO4 nanocomposites exhibited hexagonal wurtzite ZnO and Zn2TiO4 structures. The crystallite size in these nanocomposites ranged from 39.50 nm to 62.67 nm for ZnO and 21.24 nm to 26.15 nm for Zn2TiO4. Morphological observations using FESEM revealed the formation of dispersed cotton packet-like nanocomposites with sizes ranging from 18 to 350 nm. FTIR analysis showed peaks indicative of Ti–O and Zn–O bond formation, and EDX spectrum confirmed the presence of Ti, O, and Zn. UV spectrums and photocatalytic investigations confirmed the successful formation of ZnO/Zn2TiO4 nanocomposites with notable photocatalytic degradation efficiency for methylene blue dye under various conditions. These findings suggest the potential applicability of the synthesized nanocomposites for environmental pollutant degradation. [ABSTRACT FROM AUTHOR]

The diagnosis of endometrial cancer involves sequential, invasive tests to assess the thickness of the endometrium by a transvaginal ultrasound scan. In 6–33% of cases, endometrial biopsy results in inadequate tissue for a conclusive pathological diagnosis and 6% of postmenopausal women with non-diagnostic specimens are later discovered to have severe endometrial lesions. Thus, identifying diagnostic biomarkers could offer a non-invasive diagnosis for community or home-based triage of symptomatic or asymptomatic women. Herein, this study identified high-risk pathogenic nsSNPs in the NRAS gene. The nsSNPs of NRAS were retrieved from the NCBI database. PROVEAN, SIFT, PolyPhen-2, SNPs&GO, PhD-SNP and PANTHER were used to predict the pathogenicity of the nsSNPs. Eleven nsSNPs were identified as "damaging", and further stability analysis using I-Mutant 2.0 and MutPred 2 indicated eight nsSNPs to cause decreased stability (DDG scores < −0.5). Post-translational modification and protein–protein interactions (PPI) analysis showed putative phosphorylation sites. The PPI network indicated a GFR-MAPK signalling pathway with higher node degrees that were further evaluated for drug targets. The P34L, G12C and Y64D showed significantly lower binding affinity towards GTP than wild-type. Furthermore, the Kaplan–Meier bioinformatics analyses indicated that the NRAS gene deregulation affected the overall survival rate of patients with endometrial cancer, leading to prognostic significance. Findings from this could be considered novel diagnostic and therapeutic markers. [ABSTRACT FROM AUTHOR]

Silver sulfide (Ag 2 S) attached to ZnO nanorods film has been successfully prepared by a two-step hydrothermal process. The prepared photoelectrodes were characterized by Field Emission Scanning Eletron Microscopy (FESEM), Energy Dispersive Spectroscopy (EDS), X-ray diffractometry (XRD), UV-vis spectrophotometry (UV–vis) and photoelectrochemical measurements (PEC). The results revealed that Ag 2 S deposited onto the surface of ZnO nanorods was under the influence of growth temperature. The absorption in the visible region and efficient transfer of photoelectron between Ag 2 S/ZnO/ITO photoelectrode and the redox species in the electrolyte were significantly enhanced under the illumination intensity of 100 mW cm−2. The band gap values of the five different growth temperatures ranging from 50 °C to 90 °C were found to decrease from 2.93 eV to 1.57 eV. Besides, the photoelectrochemical measurements verified that Ag 2 S/ZnO nanocomposite grown at 60 °C exhibited the highest photocurrent density of 3.97 mA/cm2 at 1.0 V. The findings suggested that Ag 2 S/ZnO nanocomposite is an efficient alternative for photoelectrode applications. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A nanocomposite nanostructured Ag 2 S sensitized ZnO NRAs synthesised via hydrothermal method. • Photoelectrochemical analysis verified that the Ag 2 S/ZnO NRAs under heat treatment gave better photocurrent response. • Nanocomposite structure shows substantial improvement in charge collection efficiency. Abstract Low temperature hydrothermal method was used to produce a large surface area ZnO NRs on conductive glass. The same method was used to fabricate a photoelectrode of Ag 2 S quantum dots onto the nanorod arrays. Ag 2 S QDs/ZnO NRAs heterostructure was employed as photoanode in a standard 3-electrodes photoelectrochemical cell. A significant enhancement in the photoelectrochemical performance was observed for the Ag 2 S QDs/ZnO upon heat treatment 400 °C which displayed an impressive photoconversion efficiency of 4.08% by achieving ∼10-times higher compared to bare ZnO NRAs. This enhancement was attributed to the improved morphological structure, crystallinity and optical properties of the synthesised heterostructures. [ABSTRACT FROM AUTHOR]

Solar energy is an alternative sustainable energy resource that can be harvested using photoelectrochemical cell comprised of inorganic sensitized nanostructured oxide semiconductor electrode. In this work, pulse electrodeposition was used to deposit CdSe onto titanium dioxide nanotube arrays (TiO 2 NTAs). TiO 2 NTAs are commonly used in the nanostructured photoelectrochemical cells due to their high surface area, fewer interfacial grain boundaries and excellent charge transfer between interfaces. Duty cycle of pulse electrodeposition played an important role in the formation of CdSe nanoparticles. A significant enhancement in the photoelectrochemical performance was observed for the heterostructure of CdSe/TiO 2 NTAs. CdSe/TiO 2 NTAs prepared at 50% duty cycle exhibited maximum photocurrent of 1.94 mA cm −2 and photoconversion efficiency of 1.18% which was 59 times higher than bare TiO 2 NTAs. These results demonstrated that significant enhancement in the photoconversion efficiency could be obtained by incorporating CdSe as sensitizer into the TiO 2 nanotube arrays via pulse electrodeposition technique. [ABSTRACT FROM AUTHOR]

Highly ordered titania nanotubes (TNTs) were synthesised by an electrochemical anodization method for supercapacitor applications. However, the capacitive performance of the TNTs was relatively low and comparable to the conventional capacitor. Therefore, in order to improve the capacitive performance of the TNTs, a fast and facile electrochemical reduction method was applied to modify the TNTs (R-TNTs) by introducing oxygen vacancies into the lattice. X-ray photoelectron spectroscopy (XPS) data confirmed the presence of oxygen vacancies in the R-TNTs lattice upon the reduction of Ti4+ to Ti3+. Electrochemical reduction parameters such as applied voltage and reduction time were varied to optimize the best conditions for the modification process. The electrochemical performance of the samples was analyzed in a three-electrode configuration cell. The cyclic voltammogram recorded at 200 mV s−1 showed a perfect square-shaped voltammogram indicating the excellent electrochemical performance of R-TNTs prepared at 5 V for 30 s. The total area of the R-TNTs voltammogram was 3 times larger than the unmodified TNTs. A specific capacitance of 11.12 mF cm−2 at a current density of 20 μA cm−2 was obtained from constant current charge-discharge measurements, which was approximately 57 times higher than that of unmodified TNTs. R-TNTs also displayed outstanding cycle stability with 99% capacity retention after 1000 cycles. [ABSTRACT FROM AUTHOR]

The self-organized titania nanotube arrays (NTAs) fabricated by anodisation has gained enormous interest due to its high spatial orientation, excellent charge transfer structure, and large internal surface area; all are crucial properties influencing the absorption and propagation of light. In this study, a composite material, CdSe nanoparticle/TiO nanotube arrays (CdSe/TiO NTAs) were assembled through the insertion of CdSe nanoparticles onto the anodized TiO nanotube arrays via electrochemical deposition. The annealing temperature of CdSe/TiO NTAs was varied from 200 to 350 °C and was found to play an important role in controlling the formation of CdSe nanoparticles on TiO NTAs. Characterizations of the films were performed by using field emission scanning electron microscopy coupled with energy dispersive X-ray spectroscopy, high resolution transmission electron microscopes, X-ray diffractometry and UV-visible diffuse reflectance spectroscopy. The transient photocurrent was examined in a three-electrode system under halogen illumination by using the prepared film as the photoanode. It was found that the CdSe nanoparticles were susceptible to spread through electrochemical deposition and formed on the nanotubes by annealing in nitrogen atmosphere. The increment in annealing temperature has resulted in greater amount of CdSe loaded onto TiO nanotube arrays. Therefore, a suitable annealing temperature can enhance the particle interaction, leading to considerable improvement in PEC performance. The sensitized CdSe/TiO NTAs annealed at 250 °C displayed 84 folds improvement in photoconversion efficiency than that of bare TiO NTAs counterparts. [ABSTRACT FROM AUTHOR]

Ternary nanostructured Ag 2 S/CdS/ZnO thin film was prepared by using a simple low-cost hydrothermal method. The hexagonal phase of ZnO nanorods and CdS shells combined with monoclinic Ag 2 S quantum dots resulted in improved optical and photoelectrochemical properties. CdS shell with high absorption property efficiently compliment the energy levels of ZnO and improved the ability of light absorption. Furthermore, narrow band gap Ag 2 S also played a vital part in the light harvesting. The photoelectrochemical performance of the ternary nanostructured Ag 2 S/CdS/ZnO NRs was investigated in a mixture of Na 2 S and Na 2 SO 3 aqueous solutions under visible light illumination. The Ag 2 S/CdS/ZnO NRs were found to be more efficient than ZnO NRs, CdS/ZnO NRs, and Ag 2 S/ZnO NRs as this particular sample gave a maximum photocurrent of 5.69 mA cm −2 , which is around 2 and 1.5 times greater than CdS/ZnO NRs and Ag 2 S/ZnO NRs, respectively. Besides that, it was found that this ternary film possessed 15 times higher photocurrent density than plain ZnO NRs. This is attributed to the larger amount of visible light absorbed by the ternary nanostructured composite. [ABSTRACT FROM AUTHOR]

High density and vertically aligned zinc oxide nanorod arrays (ZnO NRs) have been prepared directly on indium-doped tin oxide (ITO) substrates via two-steps preparation: sol-gel spin coating and hydrothermal process. The nanostructured ZnO was characterized for its morphology, crystalline structure and optical properties by using field emission scanning electron microscopy (FESEM), X-ray diffractometry, and ultraviolet-visible spectroscopy respectively. In addition, the photoeletrochemical (PEC) properties were investigated through photocurrent measurements. The ZnO NRs/ITO had wurtzite-structured (hexagonal) ZnO and preferred growth along (0001) direction. When the growth time was 4 h, ZnO NRs/ITO showed impressive photoresponse. The PEC analysis verified that the ZnO NRs gave better photocurrent response and photoconversion efficiency with approximately 42 times greater than seed layer. [ABSTRACT FROM AUTHOR]

Nanorods of bismuth sulphide were prepared by thermal decomposition of bismuth N-ethyl cyclohexyl dithiocarbamate at different calcination duration. X-ray diffraction (XRD) analysis shows that at 400 °C, the precursor was fully decomposed to orthorhombic bismuth sulphide after 2 h of calcination. Besides, calcination duration does not affect the existence of Bi 2 S 3 phase. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) analyses reveal that Bi 2 S 3 nanorods with an average width ranging from 29–36 nm were obtained. Energy dispersive X-ray (EDX) analysis confirmed the atomic ratio of Bi and S close to 2:3, giving a possible composition of Bi 2 S 3 . Direct band gap energy of Bi 2 S 3 decreases from 1.83 eV to 1.54 eV as calcination time increases. [ABSTRACT FROM AUTHOR]

Synthesis of nanostructured semiconductor materials from various single source precursors has been massively explored for potential applications in modern technology. Thermal decomposition method has been employed to prepare nanoparticles zinc sulphide from zinc N-ethyl cyclohexyl dithiocarbamate precursor. Effect of heat treatment at different calcination duration on the structural, morphological, compositional and band gap properties of zinc sulphide were investigated. The obtained samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and energy dispersive X-ray (EDX) analysis. XRD showed the precursor was decomposed to hexagonal zinc sulphide after 2–6 h of calcination duration at 400 °C. The sizes of zinc sulphide (ZnS) nanoparticles obtained from TEM analysis were about 6–11 nm. The existence of the hexagonal ZnS phase is not affected by the calcination duration, while only a slight difference in the crystallinity and crystallite size of ZnS is observed from XRD analysis. EDX analyses reveal that the as-prepared ZnS nanoparticles have an approximate composition of Zn and S close to 1:1, giving a possible composition of ZnS. Besides, direct band gap energy of ZnS was found to be around 3.78–3.95 eV. [ABSTRACT FROM AUTHOR]

Despite its large band gap, ZnO has wide applicability in many fields ranging from gas sensors to solar cells. ZnO was chosen over other materials because of its large exciton binding energy (60 meV) and its stability to high-energy radiation. In this study, ZnO nanorods were deposited on ITO glass via a simple dip coating followed by a hydrothermal growth. The morphological, structural and compositional characteristics of the prepared films were analyzed using X-ray diffractometry (XRD), field emission scanning electron microscopy (FESEM), and ultraviolet-visible spectroscopy (UV-Vis). Photoelectrochemical conversion efficiencies were evaluated via photocurrent measurements under calibrated halogen lamp illumination. Thin film prepared at 120 °C for 4 h of hydrothermal treatment possessed a hexagonal wurtzite structure with the crystallite size of 19.2 nm. The average diameter of the ZnO nanorods was 37.7 nm and the thickness was found to be 2680.2 nm. According to FESEM images, as the hydrothermal growth temperature increases, the nanorod diameter become smaller. Moreover, the thickness of the nanorods increase with the growth time. Therefore, the sample prepared at 120 °C for 4 h displayed an impressive photoresponse by achieving high current density of 0.1944 mA/cm2. [ABSTRACT FROM AUTHOR]