Bacteria-Templated NiO Nanoparticles/Microstructure for an Enzymeless Glucose Sensor.

The bacterial-induced hollow cylinder NiO (HCNiO) nanomaterial was utilized for the enzymeless (without GOx) detection of glucose in basic conditions. The determination of glucose in 0.05 M NaOH solution with high sensitivity was performed using cyclic voltammetry (CV) and amperometry (i-t). The fundamental electrochemical parameters were analyzed and the obtained values of diffusion coefficient (D), heterogeneous rate constant (ks), electroactive surface coverage (Г), and transfer coefficient (alpha-α) are 1.75 × 10(-6) cm²/s, 57.65 M(-1)·s(-1), 1.45 × 10(-10) mol/cm², and 0.52 respectively. The peak current of the i-t method shows two dynamic linear ranges of calibration curves 0.2 to 3.5 µM and 0.5 to 250 µM for the glucose electro-oxidation. The Ni(2+)/Ni(3+) couple with the HCNiO electrode and the electrocatalytic properties were found to be sensitive to the glucose oxidation. The green chemistry of NiO preparation from bacteria and the high catalytic ability of the oxyhydroxide (NiOOH) is the good choice for the development of a glucose sensor. The best obtained sensitivity and limit of detection (LOD) for this sensor were 3978.9 µA mM(-1)·cm(-2) and 0.9 µM, respectively.

Intra-grain perpendicular percolated L11 CoPt thin films.

Ultrathin percolated high-Ku magnetic films with thicknesses of 2 nm are realized simply by using sputter deposition and post annealing. L11 CoPt:MgO, with Ku on the order of 10(7) erg cm(-3), was deposited on a MgO(111) substrate at 350 °C, followed by post annealing to induce complete segregation of the added MgO dopants. The optimized film shows significant enhancement of the out-of-plane coercivity, approximately an order of magnitude greater than that of the CoPt binary film, a remanence ratio close to unity, considerably reduced in-plane magnetization, sharp perpendicular magnetic reversal, and reduced surface roughness in the range of a few angstroms. Microstructure results indicate that MgO precipitates into grains within the interconnected L11 grains after appropriate post annealing. The MgO grains, with sizes in the range 2-7 nm, form coherent interfaces to the CoPt matrix and penetrate through the whole depth of the film. The development of ideal non-magnetic domain wall pinning sites explains the optimization of the perpendicular magnetic properties. The advantages of a simple fabrication process, a thin film layer structure, and remarkable enhancement of the magnetic characteristics demanded by ultrahigh-density recording reveal its potential for practical applications.

Efficient option of industrial wastewater resources in cement mortar application with river-sand by microbial induced calcium carbonate precipitation.

The industrial wastewater disposal has been growing attention for environmental protection and resource substitution, current decades. Similarly, the durability enhancement of concrete has increased attention by microbial induced CaCO3 precipitation (MICP) process (biocalcification). However, ecofriendly utilization of industrial wastewater in concrete formation is unstudied so far. The present study was carried out to evaluate the effect of industrial wastewater on the formation of cement mortar, compressive strength and water absorption. The biocement mortar strength (y) increased (y = 0.5295×2 + 1.6019×+251.05; R2 = 0.9825) with increasing percentage of organic wastewater (x) (BM0 - BM100) by MICP, where highest strength (280.75 kgf/cm2) was observed on BM100 (100% wastewater), compared to control (252.05 kgf/cm2). The water absorption (y) of biocement mortar decreases (y = -0.0251×2-0.103× + 15.965; R2 = 0.9594) with increment of wastewater (x) (%) (BM0 - BM100), where a minimum-water-absorption (14.42%) observed on BM100, compared to control (15.89%). SEM micrograph and XRD shows the formation of most-distinctive CaCO3 crystallization (aragonite/calcite) (acicular, brick shape, massive and stacked structure) inside biocement mortar (BM100), which fills the pores within cement mortar to form a denser structure, by microbial organic wastewater. Thus, present findings implied a cost-effective of MICP technology to improve the concrete properties along with the mitigation of industrial wastewater pollution, which goes some way towards solving the problem of industrial wastewater pollution.

The removal of arsenic from arsenic-bearing groundwater in In-situ and Ex-situ environment using novel natural magnetic rock material and synthesized magnetic material as adsorbent: A comparative assessment.

The removal of arsenic from groundwater is an important issue for environmental safety and human health. Research focused on the comparative assessment of arsenic removal from arsenic-bearing groundwater and arsenic-containing-synthetic water (2 mg/L) using natural magnetic material (NMM) (rock) and synthesized magnetic material (SMM) by Bacillus pasteurii and humic acid. The arsenic-bearing groundwater (97.56 ±â€¯0.05 µg/L) exceed the WHO limit (10 µg/L) of arsenic concentration for drinking water. The NMM contains dominantly magnetite, hematite, ferrihydrate, coesite, quartz, and stishovite. The NMM of natural rock exhibited the existence of iron (6.25-8.86% Fe3O4), which is widespread and important component in sedimentary rocks. The investigation on vibrating sample magnetometers (VSM) of NMM and SMM demonstrated the typical magnetization properties, which can be separated after arsenic removal process. The thermogravimetric analysis (TGA) of SMM displayed the existence of organic matter decomposition during particle synthesis. The TEM and SEM exhibited the nanoparticle particle formation within the range of 10-39 nm (10-20 nm particle Fe3O4 through B. pasteurii). FTIR spectrum (before and after removal of arsenic) indicated the existence and binding nature in between arsenic and iron. >90% of arsenic was removed from arsenic-bearing groundwater using Fe3O4, Fe3O4 (N2-Environment), Fe3O4 with humic acid, and Fe3O4 with B. pasteurii after 25 min, 8 min, 13 min and 120 min, respectively. In case of NMM in Site-A, the arsenic removal was observed very fast as 85-87% within 30 s, whereas 95-99%, 93-95% and 88-91% removal detected using the sample of Site-A, Site-B, and Site-C respectively, after 120 min at natural pH (8.31 ±â€¯0.05) of arsenic-bearing groundwater. Thus, NMM, (ecofriendly green material), can be applicable for arsenic removal from arsenic-bearing groundwater.

Fabrication of Magnetic Fe3O4 Nanoparticles with Unidirectional Extension Pattern by a Facile and Eco-Friendly Microwave-Assisted Solvothermal Method.

This study synthesizes iron(III) oxide magnetic nanoparticles (MNPs) using a facile and eco-friendly microwave-assisted solvothermal method. The highly porous particles become stable after a 60-min reaction when the temperature is fixed at 200 °C, in which the particle size is kept at 100-150 nm. The magnetic properties, crystal structure, surface morphology, and microstructures of the prepared MNPs are then analyzed. The microstructure analysis suggests that a MNP consists of numerous small Fe3O4 particles with a size smaller than 10 nm; therefore, a large amount of microcracks is observed between grains. Moreover, the orientations in these particles are very close, implying that they grow toward the same direction that may be provided by the nuclei. The prepared MNPs thus possess a highly porous structure and have a 3-times larger specific surface area than the commercially-available MNPs. Finally, the growth mechanism of iron(III) oxide MNPs by the present process is proposed.

Recording Characteristics, Microstructure, and Crystallization Kinetics of Ge/GeCu Recording Film Used for Write-Once Blu-Ray Disc.

A Ge67Cu33 (16 nm) layer and a Ge (3 nm)/Ge67Cu33 (16 nm) bilayer were grown by sputtering at room temperature and used as the recording films for write-once blue laser media. In comparison to the crystallization temperature of Ge in a GeCu film (380.7 °C-405.1 °C), the crystallization temperature of Ge in a Ge/GeCu bilayer could be further decreased to 333.7 °C-382.8 °C. The activation energies of Ge crystallization were 3.51 eV ± 0.05 eV and 1.50 eV ± 0.04 eV for the GeCu and the Ge/GeCu films, respectively, indicating that the Ge/GeCu bilayer possesses a higher feasibility in high-speed optical recording applications. Moreover, the lower activation energy would lead to a larger grain size of Ge crystallization in the Ge/GeCu bilayer after the annealing process. Between the as-deposited and the annealed states, the optical contrasts (@ 405 nm) of the GeCu and the Ge/GeCu films were 26.0% and 47.5%, respectively. This reveals that the Ge/GeCu bilayer is more suitable for the recording film of a write-once blu-ray disc (BD-R) in comparison with the GeCu film. Based on the dynamic tests performed for 2× and 4× recording speeds, the optimum jitter values of the BD-R with the Ge/GeCu recording film were 7.4% at 6.3 mW and 7.6% at 8.6 mW, respectively.