Search

The complexity of mathematical models in biology has rendered model reduction an essential tool in the quantitative biologist's toolkit. For stochastic reaction networks described using the Chemical Master Equation, commonly used methods include time-scale separation, Linear Mapping Approximation, and state-space lumping. Despite the success of these techniques, they appear to be rather disparate, and at present, no general-purpose approach to model reduction for stochastic reaction networks is known. In this paper, we show that most common model reduction approaches for the Chemical Master Equation can be seen as minimizing a well-known information-theoretic quantity between the full model and its reduction, the Kullback–Leibler divergence defined on the space of trajectories. This allows us to recast the task of model reduction as a variational problem that can be tackled using standard numerical optimization approaches. In addition, we derive general expressions for propensities of a reduced system that generalize those found using classical methods. We show that the Kullback–Leibler divergence is a useful metric to assess model discrepancy and to compare different model reduction techniques using three examples from the literature: an autoregulatory feedback loop, the Michaelis–Menten enzyme system, and a genetic oscillator. [ABSTRACT FROM AUTHOR]

Optimally increasing the catalytic activity of Co3O4‐based materials is crucial for promoting their practical applications for acetone detection; however, this still remains challenging. Herein, a strategy is proposed in this work to increase the catalytic activity of Co3O4 toward the oxidation of acetone through the synergistic effect of boron doping and chemical reduction, which can substantially improve the sensing performance for acetone detection. The characterization results confirm that the present strategy facilitates the formation of more oxygen vacancies and increases the content of Co2+ ions serving as active sites. As expected, the optimal sensor yields a higher response. To extend the practical application to the auxiliary diagnosis of diabetes through exhaled breath, the optimal sensors distinguished between acetone concentrations in the breath of healthy individuals and in the simulated breath of patients with diabetes. Detailed gas‐sensing measurements reveal that the enhanced acetone sensing performance is attributed to the increased catalytic activity of materials for oxidation of acetone by the Mars–van Krevelen, Langmuir–Hinshelwood, and Eley–Rideal mechanisms. This study provides new insights into the fabrication of high‐performance metal oxide‐based gas sensors by improving the catalytic activity of sensing materials. [ABSTRACT FROM AUTHOR]

Mercury pollution is a critical, worldwide problem and the efficient, cost-effective removal of mercury from complex, contaminated water matrices in a wide pH range from strongly acidic to alkaline has been a challenge. Here, AlZn and AlFe alloys are investigated and a new process of synergistic reduction–amalgamation and in situ layered double hydroxide (SRA-iLDH) for highly efficient capture of aqueous Hg(II) is developed using AlZn alloys. The parameters include the pH values of 1–12, the Hg(II) concentrations of 10–1000 mg L−1, and the alloy's Zn concentrations of 20%, 50% and 70% and Fe concentrations of 10%, 20% and 50%. The initial rate of Hg(II) uptake by AlZn alloys decreases with increasing Zn concentration while the overall rate is not affected. Specifically, AlZn50 alloy removes >99.5% Hg(II) from 10 mg L−1 solutions at pH 1–12 in 5 min at a rate constant of 0.055 g mg−1 min−1 and achieves a capacity of 5000 mg g−1, being the highest value reported so far. The super-performance of AlZn alloy is attributed to multiple functions of chemical reduction, dual amalgamation, in situ LDH's surface complexation and adsorption, isomorphous substitution and intercalation. This study provides a simple and highly efficient approach for removing Hg(II) from complex water matrices. [ABSTRACT FROM AUTHOR]

Chemical reduction of a [4]cumulene with cesium metal was explored, and the structural changes stemming from electron acquisition are detailed using X‐ray crystallography. It is found that the [4]cumulene undergoes dramatic geometric changes upon stepwise reduction, including bending of the cumulenic core and twisting of the endgroups from orthogonal to planar. The structural deformation is consistent with early theoretical reports that suggest that the twisting should occur upon reduction of both even and odd [n]cumulenes. The current results, on the other hand, are inconsistent with a previous experimental study of a [3]cumulene in which the predicted twisting is not observed upon reduction. DFT calculations reveal that the barrier to deformation is an order of magnitude lower in a [3]cumulene than a [4]cumulene, allowing the barrier to be overcome in the solid‐state. [ABSTRACT FROM AUTHOR]

The design of high activity catalyst for the efficiently conversion of 5‐hydroxymethylfurfural (HMF) to 2,5‐furandicarboxylic acid (FDCA) gains great interest. The rationally tailoring of electronic structure directly affects the interaction between catalysts and organic substrates, especially molecular oxygen as the oxidant. This work, the bimetallic catalysts AuPd/CeO2 were prepared by the combining method of chemical reduction and photo‐deposition, effectively concerting charge between Au and Pd and forming the electron‐rich state of Au. The increasing of oxygen vacancy concentration of CeO2 by acidic treatment can facilitate the adsorption of HMF for catalysts and enhance the yield of FDCA (99.0 %). Moreover, a series of experiment results combining with density functional theory calculation illustrated that the oxidation performance of catalyst in HMF conversion was strongly related to the electronic state of interfacial Au−Pd−CeO2. Furthermore, the electron‐rich state sites strengthen the adsorption and activation of molecular oxygen, greatly promoting the elimination of β‐hydride for the selective oxidation of 5‐hydroxymethyl‐2‐furancarboxylic acid (HMFCA) to FDCA, accompanied with an outgoing FDCA formation rate of 13.21 mmol ⋅ g−1 ⋅ min−1 at 80 °C. The perception exhibited in this research could be benefit to understanding the effects of electronic state for interfacial sites and designing excellent catalysts for the oxidation of HMF. [ABSTRACT FROM AUTHOR]

Borane–trimethylamine complex (Me3N·BH3; BTM) is the most stable of the amine–borane complexes that are commercially available, and it is cost-effective. It is a valuable reagent in organic chemistry with applications in the reduction of carbonyl groups and carbon–nitrogen double bond reduction, with considerable examples in the reduction of oximes, hydrazones and azines. The transfer hydrogenation of aromatic N-heterocycles and the selective N-monomethylation of primary anilines are further examples of recent applications, whereas the reduction of nitrobenzenes to anilines and the reductive deprotection of N-tritylamines are useful tools in the organic synthesis. Moreover, BTM is the main reagent in the regioselective cleavage of cyclic acetals, a reaction of great importance for carbohydrate chemistry. Recent innovative applications of BTM, such as CO2 utilization as feedstock and radical chemistry by photocatalysis, have extended their usefulness in new reactions. The present review is focused on the applications of borane–trimethylamine complex as a reagent in organic synthesis and has not been covered in previous reviews regarding amine–borane complexes. [ABSTRACT FROM AUTHOR]

Recently, aiming for the enhanced dispersibility of graphene-based nanomaterials in lubricating oil matrices to serve as highly efficient lubricant additives, numerous modification approaches have been extensively studied. However, these previous modification routes usually involve a tedious multistep modification process or multitudinous toxic reagents, restricting their extensive practical application. In this work, novel graphene oxide (GO) nanoadditives (RGO-g-BO) featuring excellent durable dispersion capability and remarkable tribological performance were successfully prepared via an environmentally friendly one-step approach consisting of surface grafting of long-chain bromooctadecane (BO) and in situ chemical reduction. Benefiting from the greatly improved lipophilicity (resulting from the introduction of hydrophobic long-chain alkane groups and chemical reduction), along with the miniaturization effect, RGO-g-BO exhibits superior long-term dispersion stability in the finished oil. Moreover, the tribological properties results demonstrated that the finished oil filled with RGO-g-BO nanolubricants achieved an outstanding friction-reducing and antiwear performance. Particularly, under the optimum content of RGO-g-BO (as low as 0.005 wt%), the friction coefficient as well as the wear volume of the composite finished oil were greatly reduced by 13% and 53%, respectively, as compared with nascent finished oil. Therefore, in view of the advantages of low-cost, one-step facile synthesis, desirable dispersion capability, and remarkable tribological performance, RGO-g-BO holds great prospects as a highly efficient lubrication additive in the tribology field. [ABSTRACT FROM AUTHOR]

This study aims to shed light on the elemental and mineralogical mechanisms controlling the storage and flow performances of tight conglomerates. This is achieved through the application of Field Emission Scanning Electron Microscopy (FE-SEM), Energy Dispersive Spectrometer (EDS), TESCAN Integrated Mineral Analyzer (TIMA), and geophysical logging data. The findings suggest that augmenting the Mg and CaO content in silicates can markedly enhance the storage capacity of tight conglomerates within the Upper Wuerhe Formation. Chlorite exerts a positive influence on the evolution of reservoir porosity, whereas an escalation in Na content does not foster the development of reservoirs with superior physical attributes. A reduction in the chemical index of alteration (CIA) facilitates the creation of a more expansive pore space, while an elevation in the index of component variation (ICV) augments porosity and diminishes mud content, albeit it may also curtail oil content. It is pertinent to note that an increase in ICV is not invariably advantageous. The emergence of orthoclase results in a decrease in porosity and an enhancement in permeability, whereas the progression of kaolinite adversely affects reservoir porosity. The conclusion may yield significant insights for hydrocarbon exploration in these regions, as well as in reservoirs exhibiting analogous lithologies. • The porosity of the conglomerate increases with Mg and the chlorite content. • Element and mineral properties determine the physical properties. • Geophysical and geochemical data can be integrated to study pores. [ABSTRACT FROM AUTHOR]

Silver-cobalt nanoparticles were synthesised using a chemical reduction technique. Olanzapine-cyclodextrin inclusion complex containing Ag and Ag/Co nanoparticles was examined using UV-Visible, fluorescence, computational method, FT-IR, differential scanning colorimeter, X-RD, FE-SEM, and TEM methods. A blue-shifted absorption maximum was seen in the presence of the OP/CD inclusion complex with silver and silver/cobalt nanoparticles. Multiple emission was noted in the α-CD and β-CD. TEM images conformed the formation of nanorods in Ag/OP/CD and Ag/Co/OP/CD. The pure isolated OP drug or Ag/OP/CD and Ag/Co/OP/CD do not exhibit any antibacterial activity. [ABSTRACT FROM AUTHOR]

[Display omitted] • IrCo 0.13 nanoalloy is prepared by chemical reduction and electrochemical treatment. • Abundant Co vacancies and atomic heterostructure facilitate OER and HER. • Strong interaction of Ir and Co contributes to remarkable stability and activity. • IrCo 0.13 exhibits an overpotential of 238 (OER) and 18.6 mV (HER)@10 mA cm−2, respectively. • Bifunctional IrCo 0.13 as both anode and cathode displays 1.68 V@1 A cm−2 in PEMWE. Exploring the electrocatalysts with high intrinsic activity and stability for both anode and cathode to tolerate the extremely acidic condition in proton exchange membrane water electrolyzer (PEMWE) is crucial for widespread industrial application. Herein, we constructed the bifunctional IrCo x nanoalloys with abundant metal vacancies via the combination of chemical reduction and electrochemical treatment for overall water splitting. The developed IrCo 0.13 exhibits ultra-low overpotentials of 238 mV for OER and 18.6 mV for HER at 10 mA cm−2 in 0.1 M HClO 4 , and achieves the exceptional stability of 1000 h for OER and 100 h for HER at 10 mA cm−2. Further, the cell voltage is only 1.68 V to reach a high current density of 1 A cm−2 in PEMWE with IrCo 0.13 as the both cathode and anode catalytic layer, and it shows excellent corrosion resistance in acidic environment, evidenced by 415 h stable operation at 1 A cm−2. The strong electronic interactions in the Ir-Co atomic heterostructure and the in-situ generation of Co vacancies by electrochemical oxidation synergistically contribute to the enhanced activity and stability via optimizing the electronic structure of adjacent Ir active sites, enhancing the conductivity and electrochemical active surface area of the catalyst, accelerating charge transfer and kinetics. This work provides a new perspective for designing bifunctional catalysts for practical application in PEMWE. [ABSTRACT FROM AUTHOR]

In this study, Pd@TiO2 nanostructure is formed by using TiO2 fibers obtained by the electrospinning method and chemical reduction method, and this nanostructure is used in C2, and C3 alcohol oxidation studies as an application. In addition, TiO2 is compared with the Pd catalyst to investigate the effect of TiO2. In the results obtained, peak current values of 193 and 66.7 mA cm−2 for ethanol oxidation and 127.38 and 36.18 mA cm−2 for 2‐propanol oxidation are observed for Pd@TiO2 and Pd catalysts, respectively. With the addition of TiO2 to the structure, the electrocatalytic activity of C2 and C3 alcohol oxidations increases 3–3.5 times and contributes to the onset potential at an earlier potential. It also shows higher durability and stability in long‐term tests. Moreover, the addition of TiO2 to the structure enhances the electrocatalytic activity and provides high current density and long‐term stability in alcohol oxidation. These results show that fibrous structures in combination with metals improve the effect of catalysts and exhibit high potential for their application in alcohol fuel cells. [ABSTRACT FROM AUTHOR]

It has long been considered that compositional homogeneity would not be altered on the macro-scale by solute segregation during friction stir processing (FSP) without additives. Yet in this study, for the first time, macro-scale compositional inhomogeneity was found to be induced by FSP in AZ91. Using micro X-ray fluorescence spectrometry, three regions that different from conventional microstructural zones were clearly divided from the processed material, i.e., R1 with obvious enrichment of Al and Zn, R2 with significant depletion of Al and Zn, R3 with a similar composition to base material. R1 was found almost identical to the stir zone, while R2 occupied only a part of thermo-mechanically affected zone where grain structure was refined, and the evolution of R2 should have a strong correlation with grain refinement in thermo-mechanically affected zone. The underlying mechanisms of this newly discovered phenomenon could be attributed to dissolution of β-Mg17(Al, Zn)12 in R2 and accelerated segregation of Al and Zn from R2 to R1 driven by the reduction in their chemical potentials in R1 caused by higher temperature in this region during FSP. The local mechanical property in regions of different composition was evaluated by micro-hardness. Local softening was observed in R2, which can be mainly attributed to significantly reduced solid solution strengthening resulting from the depletion of Al and Zn. [ABSTRACT FROM AUTHOR]

In this study, a series of cobalt-based spinel ferrites catalysts, including nickel, cobalt, zinc, and copper ferrites, were synthesized using the sol–gel auto-combustion method followed by a chemical reduction process. These catalysts were employed for accelerating hydrogen generation via the sodium borohydride hydrolysis process. A continuous stirred tank reactor was used to perform catalytic reactor tests. All samples were subjected to analysis using XRD, FESEM, EDX, FTIR, and nitrogen adsorption–desorption techniques. The results revealed that the cobalt-based copper ferrite sample, Co/Cu-Ferrite, exhibited superior particle distribution, and porosity characteristics, as it achieved a high hydrogen generation rate of 2937 mL/min.gcat. In addition, the higher electrical donating property of Cu-Ferrite which leads to the increase in the electron density of the cobalt active sites can account for its superior performance towards hydrolysis of NaBH4. Using the Arrhenius equation and the zero-order reaction calculation, activation energy for the sodium borohydride hydrolysis reaction on the Co/Cu-Ferrite catalyst was determined to be 18.12 kJ/mol. This low activation energy compared to other cobalt-based spinel ferrite catalysts confirms the catalyst's superior performance as well. Additionally, the outcomes from the recycling experiments revealed a gradual decline in the catalyst's performance after each cycle during 4 repetitive cycles. The aforementioned properties render the Co/Cu-Ferrite catalyst an efficient catalyst for hydrogen generation through NaBH4 hydrolysis. [ABSTRACT FROM AUTHOR]

Glycerol (GL) represents a widespread agro‐industrial waste. Its valorization is pivotal for a sustainable society because GL is a renewable compound deriving from biomass, but it has a high oxygen to carbon ratio, compared with feedstock used in the energy and chemistry sectors. Oxygen‐poor derivatives are easily and immediately transferable to the industry, avoiding a deep and pressing modification of the plants. From this perspective, keeping the carbon content but with an oxygen content reduction, we could effectively obtain the enhancement of the recovery and the use of GL converting it into attractive industrial building‐blocks. In this Review, we present and discuss the up‐to‐date results about the chemical reduction of GL into products with 3 carbon and 0, 1, or 2 oxygen atoms. The focus is on the transition metal (TM) catalysts that have made the hydrogenation reactions of GL possible, partitioning the metals into early and late, based on their position in the periodic table. This discussion will contribute to select and develop new catalysts aimed at the improvement of the yield and of the selectivity in the hydrogenation reactions of GL. [ABSTRACT FROM AUTHOR]

Abundant chemical noise in MALDI imaging mass spectrometry experiments can impede the detection of less abundant compounds of interest. This chemical noise commonly originates from the MALDI matrix as well as other endogenous compounds present in high concentrations and/or with high ionization efficiencies. MALDI imaging mass spectrometry of biological tissues measures numerous biomolecular compounds that exist in a wide range of concentrations in vivo. When ion trapping instruments are used, highly abundant ions can dominate the charge capacity and lead to space charge effects that hinder the dynamic range and detection of lowly abundant compounds of interest. Gas-phase fractionation has been previously utilized in mass spectrometry to isolate and enrich target analytes. Herein, we have characterized the use of multiple continuous accumulations of selected ions (Multi CASI) to reduce the abundance of chemical noise and diminish the effects of space charge in MALDI imaging mass spectrometry experiments. Multi CASI utilizes the mass-resolving capability of a quadrupole mass filter to perform multiple sequential ion isolation events prior to a single mass analysis of the combined ion population. Multi CASI was used to improve metabolite and lipid detection in the MALDI imaging mass spectrometry analysis of rat brain tissue. [ABSTRACT FROM AUTHOR]

In this work, density functional theory (DFT) calculations were conducted to investigate a series of transition metals (Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Ru, Rh, Pd, Ag, Hf, Ta, Os, Ir, and Pt) as single‐atom components introduced into Ti‐BPDC (BPDC=2,2′‐bipyridine‐5,5′‐dicarboxylic acid) as catalysts (M/Ti‐BPDC) for the photocatalytic reduction of CO2. The results show that Fe/Ti‐BPDC is the most active candidate for CO2 reduction to HCOOH due to its small limiting potential (−0.40 V). Ag, Cr, Mn, Ru, Zr, Nb, Rh, and Cu modified Ti‐BPDC are also active to HCOOH since their limiting potentials are moderate although the reaction mechanisms are different across these materials. Most of the studied catalysts show poor activity and selectivity to CO product because the stability of *COOH/*OCOH intermediates is significantly weaker than *OCHO/*HCOO species. The moderate binding strength of *CO on Pd/Ti‐BPDC is responsible for its superior catalytic activity toward CH3OH generation. Electronic structural analysis was performed to uncover the origin of the activity trend for CO2 reduction to different products on M/Ti‐BPDC. The calculation results indicate that the activity and selectivity of CO2 photoreduction can be effectively tuned by designing single‐atom metal‐based MOF catalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] Although solar steam generation is promising for seawater desalination, it is less effective in purifying wastewater with both salt/heavy metal ions and organic contaminants. It is thus imperative to develop multifunctional integrated solar-driven water purification systems with high solar-thermal evaporation and photocatalytic degradation efficiencies. Herein, a lamellar reduced graphene oxide (L-RGO) foam with the vertical lamellar structure is fabricated by bidirectional-freezing, lyophilization, and slight chemical reduction for water purification. The unique vertical lamellar structure not only accelerates upward transport of water for facilitating water evaporation but also endows the L-RGO foam with superb high elasticity for tuning the interlayer distance and varying interactions between the oxygen-containing groups and water molecules to adjust water energy state. As a result, the L-RGO foam achieves a superb water evaporation rate of 2.40 kg m−2 h−1 along with an energy efficiency of 95.3 % under the compressive strain of 44.7 % under 1-sun irradiation. Equally importantly, the decoration of L-RGO foam with polypyrrole is capable of efficiently degrading organic pollutants while retaining high solar steam generation performances, exhibiting great potential in the comprehensive treatment of various water sources for relieving freshwater crisis. [ABSTRACT FROM AUTHOR]

Exploration of the reduction chemistry of the 2,2'‐bipyridine (bipy) lanthanide metallocene complexes Cp*2LnCl(bipy) and Cp*2Ln(bipy) (Cp* = C5Me5) resulted in the isolation of a series of complexes with unusual composition and structure including complexes with a single Cp* ligand, multiple azide ligands, and bipy ligands with close parallel orientations. These results not only reveal new structural types, but they also show the diverse chemistry displayed by this redox‐active platform. Treatment of Cp*2NdCl(bipy) with excess KC8 resulted in the formation of the mono‐Cp* Nd(III) complex, [K(crypt)]2[Cp*Nd(bipy)2], 1, as well as [K(crypt)][Cp*2NdCl2], 2, and the previously reported [K(crypt)][Cp*2Nd(bipy)]. A mono‐Cp* Lu(III) complex, Cp*Lu(bipy)2, 3, was also found in an attempt to make Cp*2Lu(bipy) from LuCl3, 2 equiv. of KCp*, bipy, and K/KI. Surprisingly, the (bipy)1− ligands in neighboring molecules in the structure of 3 are oriented in a parallel fashion with intermolecular C⋅⋅⋅C distances of 3.289(4) Å, which are shorter than the sum of van der Waals radii of two carbon atoms, 3.4 Å. Another product with one Cp* ligand per lanthanide was isolated from the reaction of [K(crypt)][Cp*2Eu(bipy)] with azobenzene, which afforded the dimeric Eu(II) complex, [K(crypt)]2[Cp*Eu(THF)(PhNNPh)]2, 4. Attempts to make 4 from the reaction between Cp*2Eu(THF)2 and a reduced azobenzene anion generated instead the mixed‐valent Eu(III)/Eu(II) complex, [K(crypt)][Cp*Eu(THF)(PhNNPh)]2, 5, which allows direct comparison with the bimetallic Eu(II) complex 4. Mono‐Cp* complexes of Yb(III) are obtained from reactions of the Yb(II) complex, [K(crypt)][Cp*2Yb(bipy)], with trimethylsilylazide, which afforded the tetra‐azido [K(crypt)]2[Cp*Yb(N3)4], 6, or the di‐azido complex [K(crypt)]2[Cp*Yb(N3)2(bipy)], 7 a, depending on the reaction stoichiometry. A mono‐Cp* Yb(III) complex is also isolated from reaction of [K(crypt)][Cp*2Yb(bipy)] with elemental sulfur which forms the mixed polysulfido Yb(III) complex [K(crypt)]2[Cp*Yb(S4)(S5)], 8 a. In contrast to these reactions that form mono‐Cp* products, reduction of Cp*2Yb(bipy) with 1 equiv. of KC8 in the presence of 18‐crown‐6 resulted in the complete loss of Cp* ligands and the formation of [K(18‐c‐6)(THF)][Yb(bipy)4], 9. The (bipy)1− ligands of 9 are arranged in a parallel orientation, as observed in the structure of 3, except in this case this interaction is intramolecular and involves pairs of ligands bound to the same Yb atom. Attempts to reduce further the Sm(II) (bipy)1− complex, Cp*2Sm(bipy) with 2 equiv. of KC8 in the presence of excess 18‐crown‐6 led to the isolation of a Sm(III) salt of (bipy)2− with an inverse sandwich Cp* counter‐cation and a co‐crystallized K(18‐c‐6)Cp* unit, [K2(18‐c‐6)2Cp*]2[Cp*2Sm(bipy)]2 ⋅ [K(18‐c‐6)Cp*], 10. [ABSTRACT FROM AUTHOR]

This investigation aimed to explore the characteristics of reduced graphene oxide (rGO) through a comprehensive approach. The synthesis of graphene oxide (GO) began with a customized adaptation of the modified Hummer’s method, followed by subsequent chemical and thermal reduction processes. Chemical reduction involved the use of ascorbic acid, hydrazine hydrate, and sodium borohydride, while thermal reduction occurred at various temperatures in the presence of hydrogen. The study employed a diverse array of analytical techniques to unravel the structural and chemical intricacies of the material. X-ray diffraction (XRD) revealed significant changes indicative of structural transformations. Raman spectroscopy meticulously examined defects and layer formations. Scanning Electron Microscopy (SEM) visualized the evolutionary aspects of the material’s structure. UV–VIS spectroscopy is employed to analyze the optical bandgap of the sample, and the primary importance of this study lies in its application potential for solar cells. [ABSTRACT FROM AUTHOR]

Surface-enhanced Raman spectroscopy (SERS) has shown a strong Raman enhancement with bimetallic nanoparticles. The combination of the different bimetallic nanoparticles is used in the field of SERS sensors. These sensors can resonate with the organic molecules adsorbed on their surfaces for SERS enhancement. Fabricating these bimetallic, cost-effective and ultrasensitive SERS sensors is a great challenge. To overcome this challenge, a rapid fabrication method of ultrasensitive noble SERS sensors that enable sub-femtomolar detection of molecular analytes, is reported here. SERS sensor is obtained by application of the silver nanorods (AgNRs) deposited on copper nanoflowers (CuNFs) fabricated by chemical reduction and chemical etching, respectively. Purity and structural characteristics of the SERS sensor are measured qualitatively by scanning electron microscopy, transmission electron microscopy, atomic force microscopy, UV-visible spectroscopy, X-ray diffraction, Fourier transform infrared microscopy and Raman analysis. Rhodamine 6 g as an analyte analyses the sensitivity of the SERS sensor. The detection limit and enhancement factor are found to be 10−13 M and 109 respectively for AgNRs deposited CuNFs etched for 30 min. This study reveals that the AgNRs deposited CuNFs are practically found to be sensitive SERS sensors. [ABSTRACT FROM AUTHOR]

Background: The aim of the work was to evaluate the effects of different treatments viz manure as organic amendments, gypsum as amendments and nitrogen resources on salinity of saline soil. Methods: The research was conducted using a 2,4,3 factorial design. The first factor was manure (non-manure and manure), the second factor was the addition of gypsum, @ 0, 0.75, 1.5 and 3.0 ton ha-1) and third factor was source of nitrogen i.e. without N, nitrate and ammonium fertilizer. These three factors were repeated 3 times. Data were analyzed using one-way analysis of variance followed by the Duncan multiple range test for comparisons among means with a significance level of 5%. Result: This research markedly reduced pH, EC, Na and markedly increased sulfate, K content. But CEC, SAR, ESP, total N, nitrate, ammonium were not significant. The highest Ca content was in the 1.5 tons ha-1 gypsum treatment and non manure. Meanwhile, in the interaction between gypsum and N resources, the highest Mg content was 3 tons ha-1 of gypsum and nitrate. [ABSTRACT FROM AUTHOR]

The endohedral lithium fulleride, Li+@C60•−, is a potential precursor for new families of molecular superconducting and electronic materials beyond those accessible to date from C60 itself. Solid Li@C60 comprises (Li@C60)2 dimers, isostructural and isoelectronic with the (C59N)2 units found in solid azafullerene. Here, we investigate the structural and vibrational properties of Li@C60 samples synthesized by electrolytic reduction routes. The resulting materials are of high quality, with crystallinity far superior to that of their antecedents isolated by chemical reduction. They permit facile, unambiguous identification of both the reduced state of the fulleride units and the interball C-C bonds responsible for dimerization. However, severe orientational disorder conceals any crystal symmetry lowering due to the presence of dimers. Diffraction reveals the adoption of a hexagonal crystal structure (space group P63/mmc) at both low temperatures and high pressures, typically associated with close-packing of spherical monomer units. Such a situation is reminiscent of the structural behavior of the high-pressure Phase I of solid dihydrogen, H2. [ABSTRACT FROM AUTHOR]

In this work, UV-Vis spectrophotometry, High Resolution Scanning Transmission Electron Microscopes and selected experimental conditions were used to screen the colloidal system. The obtained results complement the established knowledge regarding the mechanism of nanoparticle formation. The process of gold nanoparticles formation involves a two-step reduction of Au ions to Au(0); atom association and metastable cluster formation; autocatalytic cluster growth; ultra-small particle formation (1–2 nm, in diameter); particle growth and larger particles formation; and further autocatalytic crystal growth (D > 100 nm). As a reductant of Au(III) ions, a cinnamon extract was used. It was confirmed that eugenol as one of the cinnamon extract compounds is responsible for fast Au(III) ion reduction, whereas cinnamaldehyde acts as a gold-particle stabilizer. Spectrophotometry studies were carried out to track kinetic traces of gold nanoparticle (D > 2 nm) formation in the colloidal solution. Using the Watzky—Finke model, the rate constants of nucleation and autocatalytic growth were determined. Moreover, the values of energy, enthalpy and entropy of activation for stages related to the process of nanoparticle formation (Index 1 relates to nucleation, and Index 2 relates to the growth) were determined and found to be E1 = 70.6 kJ, E2 = 19.6 kJ, ΔH1 = 67.9 kJ/mol, ΔH2 = 17 kJ/mol, ΔS1 = −76.2 J/(K·mol), ΔS2 = −204.2 J/(K·mol), respectively. In this work the limitation of each technique (spectrophotometry vs. HRSTEM) as a complex tool to understand the dynamic of the colloidal system was discussed. [ABSTRACT FROM AUTHOR]

Acanthopanax senticosus polysaccharide–nano-selenium (ASPS-SENPS) and A. selenopanax selenized polysaccharides (Se-ASPS) were synthesized, and their characterization and biological properties were compared. The acid extraction method was used to extract the polysaccharides of A. selenopanax, followed by decolorization using the hydrogen peroxide method and deproteinization based on the Sevage method, and the purification of A. senticosus polysaccharides (ASPS) was carried out using the cellulose DEAE-52 ion column layer analysis method. An A. senticosus polysaccharide–nano-selenium complex was synthesized by a chemical reduction method using ASPS as dispersants. The selenization of polysaccharides from A. selenopanax was carried out using the HNO3-Na2SeO3 method. The chemical compositions, scanning electron microscopy images, infrared spectra, and antioxidant properties of ASPS-SENPS and Se-ASPS were studied, and they were also subjected to thermogravimetric analysis. The results indicated that the optimal conditions for the synthesis of ASPS-SENPS include the following: when ASPS accounts for 10%, the ratio of ascorbic acid and sodium selenium should be 4:1, the response time should be 4 h, and the reaction temperature should be 50 °C. The most favorable conditions for the synthesis of Se-ASPS were as follows: m (Na2SeO3):m (ASPS) = 4:5, response temperature = 50 °C, and response time = 11.0 h. In the in vitro antioxidant assay, when the mass concentration of Se-ASPS and ASPS-SENPS was 5 mg/mL, the removal rates for DPPH free radicals were 88.44 ± 2.83% and 98.89 ± 3.57%, respectively, and the removal rates for ABTS free radicals were 90.11 ± 3.43% and 98.99 ± 1.73%, respectively, stronger than those for ASPS. The current study compares the physiological and bioactivity effects of ASPS-SENPS and Se-ASPS, providing a basis for future studies on polysaccharides. [ABSTRACT FROM AUTHOR]

For a chemical looping hydrogen generation system, the set of input gas flow rate needed to be adjusted on the reactivity of oxygen carriers, in order to guarantee gas conversion and to obtain higher hydrogen purity. However, the oxygen carriers often decayed upon repeated cycles, leading to pressing need for dynamic alignment between oxygen carrier reactivity and process parameters. Herein, we propose a reaction optimization control method based on machine learning methods that can establish a real-time matching system between the flow rate of input gas and the reactivity of oxygen carriers. The results show that the prediction of hydrogen yield from oxygen carriers when using the optimized Gradient Boosting Decision Tree model is in general agreement with the experimental results (R2 = 0.87, MAE = 0.49). Based on high-precision prediction results, the method is capable of realizing the input gas flow based on the predicted hydrogen production in real time in less than 10s and realizing digital twin with the expansion of the dataset. We envision that the proposed control method can accelerate the industrial application of chemical looping hydrogen generation by predicting accurate operating parameters that can reduce fuel costs and guarantee reactivity of oxygen carriers. • Interpretable relationship between reaction variables and cyclic hydrogen production through machine learning modeling. • Hyperparameter optimization of machine learning models to solve overfitting problems. • The predicted hydrogen production for the new input oxygen carriers is in general agreement with the experimental results. • Digital twin system solves the problem of unstable reduction depth in chemical looping hydrogen production. [ABSTRACT FROM AUTHOR]

The air quality in China has improved significantly in the last decade and, correspondingly, the characteristics of PM 2.5 have also changed. We studied the interannual variation of PM 2.5 in Chengdu, one of the most heavily polluted megacities in southwest China, during the most polluted season (winter). Our results show that the mass concentrations of PM 2.5 decreased significantly year-by-year, from 195.8 ± 91.0 µg/m3 in winter 2016 to 96.1 ± 39.3 µg/m3 in winter 2020. The mass concentrations of organic matter (OM), SO 4 2−, NH 4 + and NO 3 − decreased by 49.6%, 57.1%, 49.7% and 28.7%, respectively. The differential reduction in the concentrations of chemical components increased the contributions from secondary organic carbon and NO 3 − and there was a larger contribution from mobile sources. The contribution of OM and NO 3 − not only increased with increasing levels of pollution, but also increased year-by-year at the same level of pollution. Four sources of PM 2.5 were identified: combustion sources, vehicular emissions, dust and secondary aerosols. Secondary aerosols made the highest contribution and increased year-by-year, from 40.6% in winter 2016 to 46.3% in winter 2020. By contrast, the contribution from combustion sources decreased from 14.4% to 8.7%. Our results show the effectiveness of earlier pollution reduction policies and emphasizes that priority should be given to key pollutants (e.g., OM and NO 3 −) and sources (secondary aerosols and vehicular emissions) in future policies for the reduction of pollution in Chengdu during the winter months. [ABSTRACT FROM AUTHOR]

Electrocatalytic CO2 reduction (ECR) to high-value fuels and chemicals offers a promising conversion technology for achieving sustainable carbon cycles. In recent years, although great efforts have been made to develop highefficiency ECR catalysts, challenges remain in achieving high activity and long durability simultaneously. Taking advantage of the adjustable structure, tunable component, and the M-Ch (M - Sn, In, Bi, etc., Ch - S, Se, Te) covalent bonds stabilized metal centers, the p-block metal chalcogenides (PMC) based electrocatalysts have shown great potential in converting CO2 into CO or formates. In addition, the unique p-block electron structure can suppress the competitive hydrogen evolution reaction and enhance the adsorption of ECR intermediates. Seeking to systematically understand the structure-activity relationship of PMC-based ECR catalysts, this review summarizes the recent advances in designing PMC electrocatalysts for CO2 reduction based on the fundamental aspects of heterogeneous ECR process, including advanced strategies for optimizing the intrinsic activity and improving the loading density of catalytic sites, constructing highly stable catalysts, and tuning product. [ABSTRACT FROM AUTHOR]

Reduced defense against large herbivores has been suggested to be part of the "island syndrome" in plants. However, empirical evidence for this pattern is mixed. In this paper, we present two studies that compare putative physical and chemical defense traits from plants on the California Channel Islands and nearby mainland based on sampling of both field and common garden plants. In the first study, we focus on five pairs of woody shrubs from three island and three mainland locations and find evidence for increased leaf area, decreased marginal leaf spines, and decreased concentrations of cyanogenic glycosides in island plants. We observed similar increases in leaf area and decreases in defense traits when comparing island and mainland genotypes grown together in botanic gardens, suggesting that trait differences are not solely driven by abiotic differences between island and mainland sites. In the second study, we conducted a common garden experiment with a perennial herb—Stachys bullata (Lamiaceae)—collected from two island and four mainland locations. Compared to their mainland relatives, island genotypes show highly reduced glandular trichomes and a nearly 100-fold reduction in mono- and sesquiterpene compounds from leaf surfaces. Island genotypes also had significantly higher specific leaf area, somewhat lower rates of gas exchange, and greater aboveground biomass than mainland genotypes across two years of study, potentially reflecting a broader shift in growth habit. Together, our results provide evidence for reduced expression of putative defense traits in island plants, though these results may reflect adaptation to both biotic (i.e., the historical absence of large herbivores) and climatic conditions on islands. [ABSTRACT FROM AUTHOR]

Using a seed–growth method, chemical reduction in aqueous solution was used to create gold nanoparticles (AuNPs). As seeds, AuNPs have been created and used as a nucleating agent with regard to the gold colloids' anisotropic growth. The various seed quantities were added to the gold chloride-containing growth solution, and NPs have started to grow as a result. Au seeds are typically 20 nm in spherical and size in shape, while gold is 25–30 nm in size and spherical in shape. Peak absorption from nanospheres was measured between 535 nm and 530 nm. The surface plasmon band's absorption peaks moved to the short wavelength region. AuNPs are doped with PMMA to create thin films that can be used as saturation absorbers (passive Q-switching) for Q-switching in visible region and green LEDs at various frequencies in the RhB fluorescence region. Those properties include the suitability of the resulting NPs for optoelectronic applications. [ABSTRACT FROM AUTHOR]

Gold nanoparticles in their colloidal state have different colors, and the equipment for their characterization, such as UV-Vis spectrophotometers, scanning electron microscopy (SEM), and transmission electron microscopy (TEM), has high costs. The research aimed to characterize metallic gold nanoparticles by artificial vision based on the color of the samples in the colloidal state. The sensor used for the sampling was a 50 MP triple-lens camera with the optical image stabilization (OIS) of a smartphone. The Vision Acquisition and Vision Assistant blocks in the NI LabVIEW platform were used to implement an artificial vision device. The camera interface was used to identify the color of each of the 10 samples of colloidal gold nanoparticles produced by the YAG laser and chemical reduction in 15 ml of deionized water. The characterization consisted of the determination of the size and concentration of the gold nanoparticles based on their color, which ranged from pink to red wine. As a result, the artificial vision device adequately identified the color of the metallic gold nanoparticles in a colloidal state with a certainty of more than 95%, allowing the nanoparticles to be adequately characterized. Therefore, it is concluded that artificial vision adequately characterized gold nanoparticles’ wavelength, absorbance, diameter, and concentration. [ABSTRACT FROM AUTHOR]

BACKGROUND: Improvements in farmland soil organic carbon (SOC) stock enhance crop yield and soil fertility while mitigating climate change. Rational fertilization in agricultural production is crucial for safeguarding SOC stock. In this study, field experiments were conducted with different ratios of chemical fertilizer reduction and organic fertilizer substitution for three consecutive years (2018--2020) to explore their effects and interlinkages on SOC fractions, soil properties and SOC stock. RESULTS: The results showed that organic fertilizer substitution increased SOC and its fractions content, SOC stock (by 3.98-- 12.98% and 7.15--18.13%) and soil fertility index (by 11.76--49.26% and 33.33--91.47%) compared to conventional fertilization in 2019 and 2020, while chemical fertilizer reduction had the opposite effect. Moreover, soil properties (except total nitrogen to total phosphorus ratio, N/P) and SOC fractions significantly affected SOC stock, with SOC fractions contributing more than soil properties. The high sensitivity of microbial biomass carbon (MBC) and dissolved organic carbon (DOC) can indicate changes in soil carbon pool. Structural equation modeling (SEM) revealed that organic fertilizer substitution increased SOC content and stock by increasing SOC fractions [recalcitrant organic carbon (ROC) and labile organic carbon (LOC) fractions] content and soil fertility. CONCLUSIONS: Our study revealed the corresponding mechanisms of the two fertilization modes affecting SOC stock changes. The use of organic fertilizer substitution is recommended to increase SOC stocks and soil fertility in wheat fields. [ABSTRACT FROM AUTHOR]

Silver nanoparticles have shown inhibitory capabilities and its use in battling viral infections are strengthened by its potent antibacterial activity. Notably, since it directly affects antiviral efficacy, the proper choice of synthesis process for making silver nanoparticles is a vital element to be taken into consideration. The synthesis of silver nanoparticles for the treatment of viral and bacterial infections involves creating silver particles at the nanoscale with unique antimicrobial properties. Various methods exist for synthesizing silver nanoparticles, including chemical reduction, green synthesis, and physical methods. Chemical reduction involves using reducing agents to convert silver ions into silver nanoparticles. Green synthesis employs reducing agents in an environmentally friendly manner. Physical methods rely on techniques such as laser ablation or thermal evaporation to produce silver nanoparticles. In order to provide technological guidance for choosing antiviral silver nanoparticle manufacturing methods, this paper introduces and explores alternative synthesis methods for creating silver nanoparticles. [ABSTRACT FROM AUTHOR]

Probiotic products' economic value and market popularity have grown over time as more people discover their health advantages and adopt healthier lifestyles. There is a significant societal and cultural interest in these products known as foods or medicines. Products containing probiotics that claim to provide health advantages must maintain a "minimum therapeutic" level (107-106 CFU/g) of bacteria during their entire shelf lives. Since probiotic bacteria are susceptible to degradation and reduction by physical and chemical conditions (including acidity, natural antimicrobial agents, nutrient contents, redox potential, temperature, water activity, the existence of other bacteria, and sensitivity to metabolites), the most challenging problem for a food manufacturer is ensuring probiotic cells' survival and stability enhancement throughout the manufacturing stage. Currently, the use of plant-based hydrogels for improved and targeted probiotic delivery has gained substantial attention as a potential approach to overcoming the mentioned restrictions. To achieve the best possible results from hydrogels, whether used as a coating for encapsulated probiotics (with the goal of stomach protection) or as carriers for direct encapsulation of live microorganisms should be applied kind of procedures that ensure high bacterial survival during hydrogels application. This paper summarizes polysaccharides, proteins, and lipid-based hydrogels as carriers of encapsulated probiotics in delivery systems, reviews their structures, analyzes their advantages and disadvantages, studies their mechanical characteristics, and draws comparisons between them. The discussion then turns to how the criterion affects encapsulation, applications, and future possibilities. [ABSTRACT FROM AUTHOR]

Group 1 elements exhibit the lowest electronegativity values in the Periodic Table. The chemical reduction of Group 1 metal cations M+ to M(0) is extremely challenging. Common tetraaryl borates demonstrate limited redox properties and are prone to decomposition upon oxidation. In this study, by employing simple yet versatile bipyridines as ligands, we synthesized a series of redox-active borate anions characterized by NMR and X-ray single-crystal diffraction. Notably, the borate anion can realize the reduction of Li+, generating elemental lithium metal and boron radical, thereby demonstrating its potent reducing ability. Furthermore, it can serve as a powerful two-electron-reducing reagent and be readily applied in various reductive homo-coupling reactions and Birch reduction of acridine. Additionally, this borate anion demonstrates its catalytic ability in the selective two-electron reduction of CO2 into CO. Chemical reduction of alkali cations to their metals is extremely challenging. Here, the authors synthesized a series of redox-active borate anions stabilized by bipyridine ligands which can reduce lithium ions generating elemental lithium metal and borate radicals. [ABSTRACT FROM AUTHOR]

The scientific and industrial communities have shown considerable interest in the mass production of graphene in recent years. This heightened attention is attributed to graphene's promising applications across diverse fields such as electronics, energy storage, material science, biomedicine. While the potential benefits are substantial, large-scale graphene production poses significant challenges. Nonetheless, there have been noteworthy advances and dedicated efforts towards overcoming these challenges. This paper explores synthesis methods, structural distinctions, and a range of analytical techniques employed to compare properties among graphite, graphene oxide (GO), and reduced graphene oxide (rGO) samples subjected to varying reduction durations. The focus is on highlighting the efficacy of the chemical reduction method in successfully transforming GO into rGO. By extending the chemical reduction duration, the reduced graphene oxide exhibited reduced oxygen content and underwent a restoration of SP2 bonds, accompanied by the removal of oxygen functional groups. This process led to a reduction in the interplanar space between graphene layers and an increased number of exfoliated graphene layers. Notably, the resulting material demonstrated excellent stability with no coagulation in the dispersion medium and displayed improved electrical conductivity compared to graphene oxide (GO). The findings of this study suggest that optimizing the chemical reduction process, and varying reduction durations, can fine-tune the properties of reduced graphene oxide (rGO) to cater to diverse application needs. Furthermore, this approach holds promise for the scalable production of graphene. [ABSTRACT FROM AUTHOR]

The redox chemistry of cube-type titanium(IV) nitrido complexes [{Ti4(η5-C5Me5)3(R)}(μ3-N)4] (R = η5-C5Me5 (1), N(SiMe3)2 (2), η5-C5H4SiMe3 (3), and η5-C5H5 (4)) was investigated by electrochemical methods and chemical reactions. Cyclic voltammetry studies indicate that 1–4 undergo a reversible one-electron reduction at ca. −1.8 V vs. ferrocenium/ferrocene. Thus, complex 1 reacts with sodium sand in tetrahydrofuran to produce the highly reactive ionic compound [Na(thf)6][{Ti(η5-C5Me5)}4(μ3-N)4] (5). The treatment of complexes 1–4 in toluene with one equivalent of [K(C5Me5)] in the presence of macrocycles (L) leads to C10Me10 and the formation of more stable derivatives [K(L)][{Ti4(η5-C5Me5)3(R)}(μ3-N)4] (R = η5-C5Me5, L = 18-crown-6 (6), crypt-222 (7); R = N(SiMe3)2, L = 18-crown-6 (8), crypt-222 (9); R = η5-C5H4SiMe3, L = 18-crown-6 (10), crypt-222 (11); R = η5-C5H5, L = crypt-222 (12)). However, the analogous reaction of 4 with [K(C5Me5)] and 18-crown-6 affords [{(18-crown-6)K}2(μ–η5:η5-C5H5)][{Ti4(η5-C5Me5)3(η5-C5H5)}(μ3-N)4] (13) via abstraction of one cyclopentadienide group from a putative intermediate [(18-crown-6)K(μ–η5:η5-C5H5)Ti4(η5-C5Me5)3(μ3-N)4]. In contrast to the cube-type nitrido systems 1–4, the cyclic voltammogram of the trinuclear imido-nitrido titanium(IV) complex [{Ti(η5-C5Me5)(μ-NH)}3(μ3-N)] (14) does not reveal any reversible redox event and 14 readily reacts with [K(C5Me5)] to afford C5Me5H and the diamagnetic derivative [{K(μ4-N)(μ3-NH)2Ti3(η5-C5Me5)3(μ3-N)}2] (15). The treatment of 15 with two equiv. of 18-crown-6 polyethers produces the molecular species [(L)K{(μ3-N)(μ3-NH)2Ti3(η5-C5Me5)3(μ3-N)}] (L = 18-crown-6 (16), dibenzo-18-crown-6 (17)). Complex 17 further reacts with one equiv. of dibenzo-18-crown-6 to yield the ion-separated compound [K(dibenzo-18-crown-6)2][Ti3(η5-C5Me5)3(μ3-N)(μ-N)(μ-NH)2] (18) similar to the ion pair [K(crypt-222)][Ti3(η5-C5Me5)3(μ3-N)(μ-N)(μ-NH)2] (19) obtained in the treatment of 15 with cryptand-222. [ABSTRACT FROM AUTHOR]

The integrated electrocoagulation-assisted adsorption (ECA) system with a solar photovoltaic power supply has gained more attention as an effective approach for reduction chemical oxygen demand (COD) from pharmaceutical wastewater (PhWW). In this research, the ECA system was used for the treatment of PhWW. Several operating parameters were investigated, including electrode number, configuration, distance, operating time, current density, adsorption time, and temperature. A current density of 6.656 mA/cm2, six electrodes, a 20-min time, a 4 cm distance, an MP-P configuration, and a 45 °C temperature produced the maximum COD reductions, where the operating cost of conventional energy was 0.273 $/m3. The EC, adsorption, and combination of EC and adsorption processes achieved efficient COD reductions of 85.4, 69.1, and 95.5%, respectively. The pseudo-second-order kinetic model and the Freundlich isotherm fit the data of the endothermic adsorption process. Therefore, it was found that the combination processes were superior to the use of these processes in isolation to remove COD. [ABSTRACT FROM AUTHOR]

Reducing fertilizer usage is a crucial measure for achieving high-quality development in Chinese agriculture. Utilizing panel data from 31 Chinese provinces spanning from 2004 to 2019, this study empirically analyzes the dynamic relationship between fertilizer application and grain production, exploring the underlying mechanisms. The study findings reveal that the application of fertilizers maintains a positive impact on grain production. The two variables will demonstrate a dynamic alternation between "strong decoupling" and "retreat decoupling," suggesting that grain production may either increase or gradually decline, while fertilizer application exhibits a decreasing trend. Mechanism analysis reveals a distinct substitution relationship between fertilizer use efficiency and application quantity. Increasing fertilizer use efficiency while reducing application quantity still facilitates the stable and increased production of grains. Heterogeneity analysis indicates that the efficiency of fertilizer use has a more pronounced impact on grain yield in the eastern and western regions. Increasing fertilizer quantity is detrimental to wheat yield but has a promoting effect on corn yield. However, in the main grain-producing areas, increasing fertilizer quantity can enhance wheat yield but is unfavorable for the overall grain yield. Additionally, nitrogen fertilizer input has exceeded the optimal level compared to potassium fertilizer. Continuously increasing nitrogen fertilizer input will hinder the increase in grain yield. Therefore, there is a need to shift from the notion of "more fertilizer is better" and focus on improving fertilizer use efficiency to transition from the emphasis on "quantity" to "quality" of fertilizer application. [ABSTRACT FROM AUTHOR]

Hydrogen generated in severe accidental conditions poses a threat to nuclear containment once it exceeds the flammability limit in the air. A passive Autocatalytic Recombiner (PAR) device is one of the best options to tackle this scenario. In view of this, we have developed a novel breed of bimetallic Pt–Pd nano-catalysts supported over cordierite by a chemical reduction route. Pt–Pd particles with dimensions ∼4.5–11.5 nm were found to be in a metallic state and amorphous in nature. They were assessed for H 2 and O 2 recombination reactions and found to be catalytically active for the same. Their activity was also established in the presence of various probable contaminants viz. CO, CO 2 , CH 4 , relative humidity, and catalyst wetness. • Pt + Pd bimetallic catalyst was developed for hydrogen mitigation under severe accident conditions. • Ceramic support was used for enhanced properties of the catalyst. • Catalyst exhibits unaltered catalytic activity in presence of various poisons. • Catalyst retains its activity in presence of CO for wider range of concentrations. • Activation energy calculated and compared to earlier reported catalyst. [ABSTRACT FROM AUTHOR]

Aluminum (Al) stress triggers the accumulation of hydrogen peroxide (H2O2) in roots. However, whether H2O2 plays a regulatory role in aluminum resistance remains unclear. In this study, we show that H2O2 plays a crucial role in regulation of Al resistance, which is modulated by the mitochondrion-localized pentatricopeptide repeat protein REGULATION OF ALMT1 EXPRESSION 6 (RAE6). Mutation in RAE6 impairs the activity of complex I of the mitochondrial electron transport chain, resulting in the accumulation of H2O2 and increased sensitivity to Al. Our results suggest that higher H2O2 concentrations promote the oxidation of SENSITIVE TO PROTON RHIZOTOXICITY 1 (STOP1), an essential transcription factor that promotes Al resistance, thereby promoting its degradation by enhancing the interaction between STOP1 and the F-box protein RAE1. Conversely, decreasing H2O2 levels or blocking the oxidation of STOP1 leads to greater STOP1 stability and increased Al resistance. Moreover, we show that the thioredoxin TRX1 interacts with STOP1 to catalyze its chemical reduction. Thus, our results highlight the importance of H2O2 in Al resistance and regulation of STOP1 stability in Arabidopsis (Arabidopsis thaliana). Aluminum stress and the rae6 mutant induce H2O2 production in mitochondria, leading to the oxidation and destabilization of STOP1, while STOP1 reduction is catalyzed by the thioredoxin TRX1. [ABSTRACT FROM AUTHOR]

Durum wheat is one of the main crops in the Mediterranean region, which is characterized as the hotspot of climate change, with large year-to-year weather fluctuations. Although chemical input reduction in agriculture is strongly demanded, as well as healthy food, there is still a lack of stable and high-yielding crop varieties specifically adapted for organic conditions. This study evaluates the performance of fifteen durum wheat varieties in terms of suitability for organic farming in central Italy and assesses the impact of the genotype–environment interaction (GEI) on productive and quality traits. Variety performance was evaluated in field experiments over four successive seasons. In addition, a genotypic diversity analysis of 38 microsatellites associated with traits important for organic farming was performed. The AMMI (additive main effects and multiplicative interaction) stability analysis revealed that the best and most stable genotype regarding quality traits, such as thousand-kernel weight, protein content, and test weight was the ancient variety, Senatore Cappelli. The most stable and high yield was determined for the Fuego, Iride, and Mv-Pelsodur genotypes. Moreover, SSR markers that could be used for plant breeding, targeting organic farming systems based on molecular markers and GEI results, were identified. [ABSTRACT FROM AUTHOR]

A reliable, rapid, and inexpensive nano-sized chemosensor is presented for methamidophos (MET) — an insecticide. Poly(lactic acid) (PLA)-stabilized gold nanoparticles (AuNPs) were synthesized by a simple one-pot, two-phase chemical reduction method. The synthesized PLA-AuNPs were subsequently employed for selective, efficient, and quantitative detection of MET. MET is one of the highly toxic pesticides used for eradication of agricultural and urban insects. Upon the addition of MET, the wine-red color of PLA-AuNPs swiftly transformed into greyish-blue, further corroborated by a significant bathochromic and hyperchromic shift in the SPR band. The presence of other interfering insecticides, metal salts, and drugs did not have any pronounced effect on quantitative MET detection. The detection limit, the quantification limit, and linear dynamic range of MET utilizing PLA-AuNPs were 0.0027 µM, 0.005 µM, and 0.005–1000 µM, respectively. The PLA-AuNP-based assay renders an efficient, rapid, accurate, and selective quantification of MET in food, biological, and environmental samples. The proposed sensor provides an appropriate platform for fast and on-the-spot determination of MET without requiring a well-equipped lab setup. [ABSTRACT FROM AUTHOR]

The recent work investigates the relationship between the characteristics of the Raman spectra and the oxidation temperature of thermal-treated graphite samples in air at various temperatures ranging from 200°Cto 800 °C. Our findings indicate that thermal oxidation of graphite in air leads to the enhancement of the 2D vibration pattern while reducing the intensity of the D vibration pattern. Moreover, we report that chemical reduction begins at 550 °C. Furthermore, our results demonstrate that thermal oxidation causes a decrease in the disorder within the samples. [ABSTRACT FROM AUTHOR]

The use of organic dyes has surged across industries like textiles, plastics, and construction. Contaminated water with these dyes is released into the environment, endangering both humans and ecosystems. In this research, we synthesized ternary composites of NiAl-LDH/Ag/g-C3N4 using hydrothermal methods. We conducted a comprehensive examination of the prepared catalysts, employing various analytical techniques to assess their structural, optical, morphological, and surface chemical properties. The surface area analysis confirmed a mean pore volume of 0.245 cm³/g, a favorable surface area of 36.4 cm2/g, and a pore diameter of 2.68 nm. The creation of strong interfacial contact between NiAL LDH, Ag, and g-C3N4 caused the charges to be separated for a long time. The degradation of methylene blue (MB) dye under the influence of solar light was used to test the photocatalytic performance of the as-prepared catalyst. A set of reusability experiments was carried out over four cycles using the photocatalyst, and the characterization findings demonstrated that the preservation of crystalline planes plays a pivotal role in achieving its high efficiency. Notably, a remarkable 99.1% reduction in chemical oxygen demand (% COD) was achieved for MB. Additionally, scavenger studies were undertaken to identify the primary reactive species involved in the process. The maximum degradation efficiency of 99.60%, with the highest R2 value of 0.9921 was achieved for the photocatalytic degradation of MB respectively in 160 min. These results indicated that the new z-scheme ternary photocatalyst can be used as an efficient, green, effective, and recyclable for the photocatalytic degradation of organic pollutants. [ABSTRACT FROM AUTHOR]

Sand storms and fine dust are known as the most important atmospheric problems in many windy regions around the world, especially in arid and semi-arid areas. Besides all the obvious negative effects of fine dust on human life, this phenomenon can extremely reduce the physical and chemical quality of output water from treatment plants into the distribution systems. In order to show and evaluate the impact of fine dust on the physico-chemical quality of the water, a long-term (three years: 2017–2020) experimental investigation was done in the Sistan region (Iran) which is one of the most popular regions in the world with high amount of annual fine dust level. The final results showed that the most physical and chemical quality indices of output water from the local treatment plants became progressively worse after the fine dust process. The total dissolved solids (TDS) and turbidity of the water, which could even obviously be seen in the samples, were increased so that the TDS level was raised to more than 850 ppm. The level of some metals such as Fe, Ca, Mg, Na, and K increased significantly but stood within the standard levels. pH level was increased to up to 8.3 in some water samples. In addition, high levels of NO3, SO4, F, EC, HCO3, Cl, CO3, and PO4 were observed in all water samples after fine dust processes. Also, the t-student analysis showed that there was a high correlation between wind speeds and the reduction of physical and chemical quality indices in most of the water samples. Finally, the experimental analysis showed that most of these chemical elements originated from the vast bed (5,660 km2) of the dried-up Hamun's Lake where the winds were blown over. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) nanoparticles, due to their favorable water solubility, compared to graphene (GA), are a hot research topic in biomedical and pharmaceutical research. However, GO clinical translation may be complicated by its high surface/volume ratio enhancing the interaction with human blood components. In fact, GO's bi-dimensional nature and strong negative charge may lead to severe biological effects, such as thrombogenicity and immune cell activation. This study explores the impact of further GO surface chemical modulation on major adverse effects: blood plasma coagulation and hemolysis. To this aim, we refined GO nanoparticles by fine-tuned reduction chemistry, esterification and introduction of negative or positive charges. With this approach, we were able to mitigate plasma coagulation and hemolysis at variable degrees and to identify GO derivatives with improved biocompatibility. This opens the door to the progress of graphene-based nanotheranostic applications. [ABSTRACT FROM AUTHOR]

This study provides a chemical mechanism reduction strategy based on entropy production analyses in both auto-ignition and laminar flames, which enhances the predictive accuracy for laminar burning velocities. In addition to chemical reactions, other irreversible sources causing entropy generation, such as mass diffusion and heat conduction, are considered in the modified approach. Specifically, initial skeletal mechanisms are first generated based on important reactions that contribute to entropy production in auto-ignition processes. Mechanism patches are then constructed to include important species and reactions, which contribute to entropy production from mass diffusion and heat conduction in laminar premixed flames beyond the pre-defined thresholds, respectively. Finally, the initial skeletal mechanisms and mechanism patches are combined to establish the final skeletal mechanisms. In this way, two final skeletal mechanisms for n-dodecane, consisting of 162 species and 2276 reactions, and 160 species and 1916 reactions, respectively, are developed from the detailed POLIMI mechanism with 451 species and 17,848 reactions. The two final skeletal mechanisms are proven to accurately predict laminar burning velocities and entropy production in n-dodecane flames with insignificant variations in the simulation results compared to the detailed mechanism, while their accuracy in predicting ignition delay times relies on the initial skeletal mechanisms. Specifically, the reduced mechanism with 160 species and 1916 reactions exhibits less satisfactory performance in predicting ignition delay compared to that with 162 species and 2276 reactions, indicating that a lower threshold is required to generate the initial skeletal mechanism through entropy production analysis of homogeneous auto-ignition processes. Additionally, compared with the reduced mechanisms with similar sizes obtained with other mechanism reduction strategies, the two final skeletal mechanisms accurately capture the characteristics of laminar burning velocities and ignition delay times, with similar calculation time required. [ABSTRACT FROM AUTHOR]

Benchtop NMR provides improved accessibility in terms of cost, space, and technical expertise. In turn, this encourages new users into the field of NMR spectroscopy. Unfortunately, many interesting samples in education and research, from beer to whole blood, contain significant amounts of water that require suppression in 1H NMR in order to recover sample information. However, due to the significant reduction in chemical shift dispersion in benchtop NMR systems, the sample signals are much closer to the water resonance compared to those in a corresponding high‐field NMR spectrum. Therefore, simply translating solvent suppression experiments intended for high‐field NMR instruments to benchtop NMR systems without careful consideration can be problematic. In this study, the effectiveness of several popular water suppression schemes was evaluated for benchtop NMR applications. Emphasis is placed on pulse sequences with no, or few, adjustable parameters making them easy to implement. These fall into two main categories: (1) those based on Pre‐SAT including Pre‐SAT, PURGE, NOESY‐PR, and g‐NOESY‐PR and (2) those based on binomial inversion including JRS and W5‐WATERGATE. Among these schemes, solvent suppression sequences based on Pre‐SAT offer a general approach for easy solvent suppression for samples with higher analyte concentrations (sucrose standard and Redbull™). However, for human urine, binomial‐like sequences were required. In summary, it is demonstrated that highly efficient water suppression approaches can be implemented on benchtop NMR systems in a simple manner, despite the limited spectral dispersion, further illustrating the potential for widespread implementation of these approaches in education and research. [ABSTRACT FROM AUTHOR]