Tailoring the Morphology of Cost-Effective Vanadium Diboride Through Cobalt Substitution for Highly Efficient Alkaline Water Oxidation.

Design and development of efficient, economical, and durable electrocatalysts for oxygen evolution reaction (OER) are of key importance for the realization of electrocatalytic water splitting. To date, VB2 and its derivatives have not been considered as electrocatalysts for water oxidation. Herein, we developed a series of electrocatalysts with a formal composition of V1-xCoxB2 (x = 0, 0.05, 0.1, and 0.2) and employed them in an oxygen-evolving reaction. The incorporation of Co into the VB2 structure caused a dramatic transformation in the morphology, resulting in a super low overpotential of 200 mV at 10 mA cm-2 for V0.9Co0.1B2 and displaying much greater performance compared to the noble-metal catalyst RuO2 (290 mV). The longevity of the best-performing sample was assessed through the exposure to the current density of 10 mA cm-2, showing relative durability after 12 h under 1 M KOH conditions. The Faradaic efficiency tests corroborated the initiation of OER at 1.45 V (vs RHE) and suggested a potential region of 1.50-1.55 V (vs RHE) as the practical OER region. The facile electron transfer between metal(s)-metalloid, high specific surface area, and availability of active oxy-hydroxy species on the surface were identified as the major contributors to this superior OER performance.

Bactericidal behavior of silver nanoparticle decorated nano-sized magnetic hydroxyapatite.

Methicillin-resistant Staphylococcus aureus (MRSA) is the most common cause of acute bacterial arthritis. Due to the increase in antibiotic resistance in these bacteria, the discovery of new antibacterial agents has become one of the hot topics in the scientific community. Here, we prepared a nano-sized porous biocompatible magnetic hydroxyapatite through a solvothermal method. Then, we adopted a post-synthesis modification strategy to modify its surface for the stabilization of Ag NPs through a green reduction by the euphorbia plant extract. Moreover, the results show that the prepared composite perfectly prevents the aggregation of Ag NPs. This composite was used as a bactericidal and antibiofilm agent against MRSA bacteria in an in vitro environment, which showed excellent results. Also, the cell viability assay indicates that the prepared composite has low cytotoxicity, making it a perfect antibacterial agent for in vivo experiments.

Scalable Solid-State Synthesis of Carbon-Supported Ir Electrocatalysts for Acidic Oxygen Evolution Reaction: Exploring the Structure-Activity Relationship.

Enhancing iridium (Ir)-based electrocatalysts to achieve high activity and robust durability for the oxygen evolution reaction (OER) in acidic environments has been an ongoing mission in the commercialization of proton exchange membrane (PEM) electrolyzers. In this study, we present the synthesis of carbon-supported Ir nanoparticles (NPs) using a modified impregnation method followed by solid-state reduction, with Ir loadings of 20 and 40 wt % on carbon. Among the catalysts, the sample with an Ir loading of 20 wt % synthesized at 1000 °C with a heating rate of 300 °C/h demonstrated the highest mass-normalized OER performance of 1209 A gIr-1 and an OER current retention of 80% after 1000 cycles of cyclic voltammetry (CV). High-resolution STEM images confirmed the uniform dispersion of NPs, with diameters of 1.6 ± 0.4 nm across the support. XPS analysis revealed that the C-O and C═O peaks shifted slightly toward higher binding energies for the best-performing catalyst. In comparison, the metallic Ir state shifted toward lower binding energies compared to other samples. This suggests electron transfer from the carbon support to the Ir NPs, indicating a potential interaction between the catalyst and the support. This work underscores the strong potential of the solid-state method for the scalable synthesis of supported Ir catalysts.

In Situ Design of a Nanostructured Interface between NiMo and CuO Derived from Metal-Organic Framework for Enhanced Hydrogen Evolution in Alkaline Solutions.

Hydrogen shows great promise as a carbon-neutral energy carrier that can significantly mitigate global energy challenges, offering a sustainable solution. Exploring catalysts that are highly efficient, cost-effective, and stable for the hydrogen evolution reaction (HER) holds crucial importance. For this, metal-organic framework (MOF) materials have demonstrated extensive applicability as either a heterogeneous catalyst or catalyst precursor. Herein, a nanostructured interface between NiMo/CuO@C derived from Cu-MOF was designed and developed on nickel foam (NF) as a competent HER electrocatalyst in alkaline media. The catalyst exhibited a low overpotential of 85 mV at 10 mA cm-2 that rivals that of Pt/C (83 mV @ 10 mA cm-2). Moreover, the catalyst's durability was measured through chronopotentiometry at a constant current density of -30, -100, and -200 mA cm-2 for 50 h each in 1.0 M KOH. Such enhanced electrocatalytic performance could be ascribed to the presence of highly conductive C and Cu species, the facilitated electron transfer between the components because of the nanostructured interface, and abundant active sites as a result of multiple oxidation states. The existence of an ionized oxygen vacancy (Ov) signal was confirmed in all heat-treated samples through electron paramagnetic resonance (EPR) analysis. This revelation sheds light on the entrapment of electrons in various environments, primarily associated with the underlying defect structures, particularly vacancies. These trapped electrons play a crucial role in augmenting electron conductivity, thereby contributing to an elevated HER performance.

Designing In Situ Grown Ternary Oxide/2D Ni-BDC MOF Nanocomposites on Nickel Foam as Efficient Electrocatalysts for Electrochemical Water Splitting.

The security of future energy, hydrogen, is subject to designing high-performance, stable, and low-cost electrocatalysts for hydrogen and oxygen evolution reactions (HERs and OERs), for the realization of efficient overall water splitting. Two-dimensional (2D) metal-organic frameworks (MOFs) introduce a large family of materials with versatile chemical and structural features for a variety of applications, such as supercapacitors, gas storage, and water splitting. Herein, a series of nanocomposites based on NCM/Ni-BDC@NF (N=Ni, C=Co, M:F=Fe, C=Cu, and Z=Zn, BDC: benzene dicarboxylic acid, NF: nickel foam) were directly developed on NF using a facile yet scalable solvothermal method. After coupling, the electronic structure of metallic atoms was well-modulated. Based on the XPS results, for the NCF/Ni-BDC, cationic atoms shifted to higher oxidation states, favorable for the OER. Conversely, for the NCZ/Ni-BDC and NCC/Ni-BDC nanocomposites, cationic atoms shifted to lower oxidation states, advantageous for the HER. The as-prepared NCF/Ni-BDC demonstrated prominent OER performance, requiring only 1.35 and 1.68 V versus a reversible hydrogen electrode to afford 10 and 50 mA cm-2 current densities, respectively. On the cathodic side, NCZ/Ni-BDC exhibited the best HER activity with an overpotential of 170 and 350 mV to generate 10 and 50 mA cm-2, respectively, under 1.0 M KOH medium. In a two-electrode alkaline electrolyzer, the assembled NCZ/Ni-BDC (cathode) ∥ NCF/Ni-BDC (anode) couple demanded a cell voltage of only 1.58 V to produce 10 mA cm-2. The stability of NCF/Ni-BDC toward OER was also exemplary, experiencing a continuous operation at 10, 20, and 50 mA cm-2 for nearly 45 h. Surprisingly, the overpotential after OER stability at 50 mA cm-2 dropped drastically from 450 to 200 mV. Finally, the faradaic efficiencies for the overall water splitting revealed the respective values of 100 and 85% for the H2 and O2 production at a constant current density of 20 mA cm-2.

Metal doped layered MgB2 nanoparticles as novel electrocatalysts for water splitting.

Growing environmental problems along with the galloping rate of population growth have raised an unprecedented challenge to look for an ever-lasting alternative source of energy for fossil fuels. The eternal quest for sustainable energy production strategies has culminated in the electrocatalytic water splitting process integrated with renewable energy resources. The successful accomplishment of this process is thoroughly subject to competent, earth-abundant, and low-cost electrocatalysts to drive the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), preferably, in the same electrolyte. The present contribution has been dedicated to studying the synthesis, characterization, and electrochemical properties of newfangled electrocatalysts with the formal composition of Mg1-xTMxB2 (x = 0.025, 0.05, and 0.1; TM (transition metal) = Fe and Co) primarily in HER as well as OER under 1 M KOH medium. The electrochemical tests revealed that among all the metal-doped MgB2 catalysts, Mg0.95Co0.05B2 has the best HER performance showing an overpotential of 470 mV at - 10 mA cm-2 and a Tafel slope of 80 mV dec-1 on account of its high purity and fast electron transport. Further investigation shed some light on the fact that Fe concentration and overpotential for HER have adverse relation meaning that the highest amount of Fe doping (x = 0.1) displayed the lowest overpotential. This contribution introduces not only highly competent electrocatalysts composed of low-cost precursors for the water-splitting process but also a facile scalable method for the assembly of highly porous electrodes paving the way for further stunning developments in the field.

Optimization and quality evaluation of infrared-dried kiwifruit slices.

Infrared drying characteristics of kiwifruits under natural and forced drying air convection with different conditions were investigated. An experimental study along with statistical analysis aimed to evaluate quality characteristics of infrared-dried kiwifruit slices, in terms of drying time, rehydration ratio and shrinkage as a function of infrared power levels, slice thicknesses, slice distance from the infrared lamps, and air velocity. Response surface methodology was used for optimization of drying parameters with employing desirability function. Minimum drying time, shrinkage, and maximum rehydration ratio assumed as criteria for optimizing drying conditions of kiwifruit slices were strongly dependent on the drying conditions. All operating variables had a significant effect on total responses, but slice thickness almost was the most prominent factor. The slices dried at the highest power level, the lowest distance from the Infrared lamp, the least thickness, and air velocity showed a higher rehydration capacity than slices dried at the other conditions.

Infrared drying effects on the quality of eggplant slices and process optimization using response surface methodology.

The aim of this work was to study the effect of thickness of samples, air velocity and infrared power on the drying kinetics and quality attributes of blanched eggplant slices during infrared drying. The drying experiments were made by Response Surface Methodology (RSM) based on a Box-Behnken design (BBD). Experiments were conducted at a thickness of 3, 5, and 7 mm, air velocity of 0.5, 1.25, and 2 m/s, as well as at infrared power 1000, 1500, and 2000 W. The drying time was affected by operating parameters. The drying processes increased total phenolic content and potassium content, significantly. The total color difference (ΔE) was in the range of 10.22-25.14. In the end, this process was optimized for reaching the best experimental condition.

Mathematical modelling of infrared-dried kiwifruit slices under natural and forced convection.

In this work, the effect of the radiation intensity, slice thickness, and the distance between slices and infrared lamps under natural drying air and the effect of slice thickness and air velocity under forced drying air on the moisture diffusion characteristics and the drying rate of kiwifruit slices during infrared drying were investigated. The drying of kiwifruit happened in the falling rate period, and no constant-rate period was observed in the drying curves. One hundred models were fitted to the drying data. Among the models, the exponential dsecay function model and modified two-term exponential-V model and the artificial neural networks with 4-5-7-1 and 3-5-5-1 topologies, hyperbolic tangent sigmoid transfer function, and Levenberg-Marquardt training algorithm presented the best results and showed the goodness of fit with the experimental data for the former and latter systems, respectively. The diffusivities varied between 1.216 × 10-10-8.997 × 10-10 m2/s and 2.567 × 10-10-10.335 × 10-10 m2/s for natural and forced drying air systems, respectively.

Comparison of serum procalcitonin level with erythrocytes sedimentation rate, C-reactive protein, white blood cell count, and blood culture in the diagnosis of bacterial infections in patients hospitalized in Motahhari hospital of Urmia (2016).

Blood infection is one of the causes of morbidity in hospitalized patients. While some scholars have identified procalcitonin (PCT) as a potential biomarker for the diagnosis of blood infection, others have questioned its diagnostic value. Thus, the present study was conducted to compare the diagnostic values of PCT with C-reactive protein (CRP), erythrocytes sedimentation rate (ESR), white blood cell (WBC) count, and blood culture in patients with bacterial blood infections. In a prospective case-control study, 45 septic patients (6 months-5 years old), who were hospitalized in Shahid Motahhari Hospital of Urmia over the year 2016 and 45 patients with noninfectious diseases, whose gender and age range were similar to the members of the septic group, were examined. The participants' blood samples were taken for the sake of blood culture and measurement of PCT level, ESR, and CRP. Finally, the collected data were analyzed through the SPSS-21 software. the results indicated that the average PCT, ESR, CRP, and WBC count was significantly higher in septic patients. Moreover, the blood culture of patients with negative or intermediate serum PCT levels was negative, while 50% of blood culture results in patients with positive PCT were positive and the rest were negative. Finally, a significant relationship was detected between the frequency of blood culture results and results of serum PCT tests (P = 0.003). serum PCT level can be considered a diagnostic marker of bacterial infections. If used in conjunction with tests of CRP, ESR, and WBC count, the PCT test can enhance the diagnosis of bacterial infections.

Effect of electric and magnetic fields on impurity binding energy in zinc-blend symmetric InGaN/GaN multiple quantum dots.

The binding energy of ground state for hydrogenic impurity in multiple quantum dots is calculated in the framework of effective-mass approximation and using a variational method. It is shown that the binding energy is a function of the size of dots, impurity position and external fields strength. The binding energy has a maximum value when the impurity is located on the center of dots and decreases for other impurity positions. The external electric and magnetic fields change the magnitude and the position of peaks. PACS Codes 73.20.D; 71.21.La; 71.55.Eq.

Longitudinal range expansion and cryptic eastern species in the western Palaearctic oak gallwasp, Andricus coriarius.

The oak gallwasp Andricus coriarius is distributed across the Western Palaearctic from Morocco to Iran. It belongs to a clade of host-alternating Andricus species that requires host oaks in two sections of Quercus subgenus Quercus to complete its lifecycle, a requirement that has restricted the historic distribution and dispersal of members of this clade. Here we present nuclear and mitochondrial sequence evidence from the entire geographic range of A. coriarius to investigate the genetic legacy of longitudinal range expansion. We show A. coriarius as currently understood to be para- or polyphyletic, with three evolutionarily independent (but partially sympatric) lineages that diverged c. 10 million years ago (mya). The similarities in gall structure that have justified recognition of single species to date thus represent either strong conservation of an ancestral state or striking convergence. All three lineages originated in areas to the east of Europe, underlining the significance of Turkey, Iran and the Levant as 'cradles' of gallwasp evolution. One of the three lineages gave rise to all European populations, and range expansion from a putative Eastern origin to the present distribution is predicted to have occurred around 1.6 mya.

The phylogeographical clade trade: tracing the impact of human-mediated dispersal on the colonization of northern Europe by the oak gallwasp Andricus kollari.

Human dispersal of organisms is an important process modifying natural patterns of biodiversity. Such dispersal generates new patterns of genetic diversity that overlie natural phylogeographical signatures, allowing discrimination between alternative dispersal mechanisms. Here we use allele frequency and DNA sequence data to distinguish between alternative scenarios (unassisted range expansion and long range introduction) for the colonization of northern Europe by an oak-feeding gallwasp, Andricus kollari. Native to Mediterranean latitudes from Portugal to Iran, this species became established in northern Europe following human introduction of a host plant, the Turkey oak Quercus cerris. Colonization of northern Europe is possible through three alternative routes: (i) unassisted range expansion from natural populations in the Iberian Peninsula; (ii) unassisted range expansion from natural populations in Italy and Hungary; or (iii) descent from populations imported to the UK as trade goods from the eastern Mediterranean in the 1830s. We show that while populations in France were colonized from sources in Italy and Hungary, populations in the UK and neighbouring parts of coastal northern Europe encompass allozyme and sequence variation absent from the known native range. Further, these populations show demographic signatures expected for large stable populations, rather than signatures of rapid population growth from small numbers of founders. The extent and spatial distribution of genetic diversity in the UK suggests that these A. kollari populations are derived from introductions of large numbers of individuals from each of two genetically divergent centres of diversity in the eastern Mediterranean. The strong spatial patterning in genetic diversity observed between different regions of northern Europe, and between sites in the UK, is compatible with leptokurtic models of population establishment.