Changes In Chemical Environment Research Articles

Chemical Spatiotemporal Characteristics and Environmental Driving Factors of Groundwater in Hetao Irrigation Area

To explore the chemical characteristics and environmental factors of groundwater in the Hetao Irrigation Area of Inner Mongolia, five irrigation fields, including UulanBuh, Jiefangzha, Yongji, Yichang, and Wulat, were selected as the research area. From 72 groundwater observation wells, a total of 216 groundwater samples were collected throughout three typical periods： the end of freeze-thaw （March）, the middle of irrigation （July）, and the end of autumn watering （November）. Comprehensive methods were utilized, such as statistical analysis, Piper three-line diagram, Gibbs diagram, ion ratio, and principal component analysis, to explore the changes in the groundwater chemical environment and the environmental driving factors of groundwater component formation. The groundwater drinking suitability was evaluated using the water quality index （WQI）, and the irrigation suitability was analyzed using the USSL and Wilcox plots. The results indicated that the groundwater in the research areas was generally saline, and the total anion and cation concentrations in each period in ascending order were as follows： late freeze-thaw stage, late autumn irrigation stage, and mid-irrigation stage, with Na+ and Cl- being the major contributing ions. The chemical type of groundwater was dominated by Cl-Na, followed by Cl·SO4-Ca·Mg and a coexistence with SO4-Ca·Mg, HCO3·Cl-Na, HCO3-Na, and HCO3-Ca·Mg. Based on WQI values, the shallow groundwater in Hetao Irrigation District was mainly classified as Class IV and Class V, and the quality was poor in general. According to the USSL diagram and Wilcox diagram, the comprehensive evaluation results showed that the salinity and sodium concentration of shallow groundwater in the irrigation area were generally high. A total of 80.6% of the water samples during the late freeze-thaw period, 76.1% during the mid-irrigation period, and 77.6% during the late autumn irrigation period lacked irrigation suitability. Two major controlling factors of groundwater chemical characteristics were present in the study area, namely, evaporation and rock weathering, and Na+ and Cl- mainly came from the dissolution and cation exchange of salt rocks. Agricultural irrigation and drought were the chief driving factors of groundwater chemical evolution in the Hetao Irrigation Area. The study provides technical support for optimizing agricultural management measures and a theoretical reference for rational utilization of groundwater resources in the Yellow River irrigation area of Inner Mongolia.

An innovative approach to control the Hf/Ti ratio in monolayers grown via atomic partial layer deposition

The Hf/Ti ratio was precisely controlled at monolayer thickness using atomic partial layer deposition (APLD). HfxTi1−xO2 films with varying Hf concentrations were deposited by adjusting the pulse time of Hf precursors within a single atomic layer. Characterization using x-ray reflectivity, x-ray photoelectron spectroscopy, and spectroscopic ellipsometry confirmed the presence of Hf, Ti, and O in the films. Increasing the Hf content caused the binding energies of the O 1s peak to shift to higher values, indicating a chemical environment change from TiO2-like to HfO2-like. A higher Hf content also increased the relative atomic percentages of Hf, Ti, and O, altering the film properties. The mass density and optical properties were notably sensitive to changes in the Hf/Ti ratio at monolayer thickness. The potential of APLD to reduce dimensionality through precise control of both thickness and composition renders it especially appropriate for applications requiring highly specific material properties.

Adsorption and Distribution of Triplex-Hybridizing Bioconjugated Gold Nanoclusters Inside Spermatozoa- A Study Using Confocal Microscopy and Fluorescence Lifetime Imaging.

The study of the interactions between biofunctionalized gold nanoclusters (Au NCs) and spermatozoa is highly relevant to evaluate the potential of Au NCs as imaging probes and transfection agents in reproductive biology. In this work, confocal laser scanning microscopy (CLSM) was used to investigate the distribution of Au NCs bioconjugated with peptide (nuclear localisation sequence, NLS) and oligonucleotide (locked nucleic acid, LNA) ligands in bovine spermatozoa. Fluorescence lifetime imaging (FLIM) was employed to detect changes in the NC's chemical environment. We observed a pronounced regio-selective accumulation of the bioconjugates in spermatozoa with high concentration at the equatorial segment. Furthermore, 3D-CLSM showed successful non-endosomal cellular uptake of the conjugates by intact sperm cells and the distribution of the bioconjugates was found to be influenced by the ligand types. Interestingly, the FLIM data showed differences in lifetime depending on membrane integrity. Furthermore, ligand-dependent changes in lifetime between NC bioconjugates carrying peptide and oligonucleotide ligands were found, probably attributed to specific interactions with sperm cell compartments.

Self-Reporting Therapeutic Protein Nanoparticles.

We present a modular strategy to synthesize nanoparticle sensors equipped with dithiomaleimide-based, fluorescent molecular reporters capable of discerning minute changes in interparticle chemical environments based on fluorescence lifetime analysis. Three types of nanoparticles were synthesized with the aid of tailor-made molecular reporters, and it was found that protein nanoparticles exhibited greater sensitivity to changes in the core environment than polymer nanogels and block copolymer micelles. Encapsulation of the hydrophobic small-molecule drug paclitaxel (PTX) in self-reporting protein nanoparticles induced characteristic changes in fluorescence lifetime profiles, detected via time-resolved fluorescence spectroscopy. Depending on the mode of drug encapsulation, self-reporting protein nanoparticles revealed pronounced differences in their fluorescence lifetime signatures, which correlated with burst- vs diffusion-controlled release profiles observed in previous reports. Self-reporting nanoparticles, such as the ones developed here, will be critical for unraveling nanoparticle stability and nanoparticle-drug interactions, informing the future development of rationally engineered nanoparticle-based drug carriers.

The Binding Mechanism Between Cyclodextrins and Anticancer Drug Noscapine: A Spectroscopic and Molecular Docking Study.

In this paper the binding of noscapine (NOS) as an anticancer drug with poor bioavailability and low solubility with beta and methyl-beta cyclodextrins (β-CD and M-β-CD) as the biocompatible drug carriers were discussed using ultraviolet-visible, fluorescence and nuclear magnetic resonance spectroscopy, as well as molecular docking. The absorption of NOS changed when it was bound to both cyclodextrins, resulting in a hyperchromic shift. It formed a 1:1 stoichiometry inclusion complex with both cyclodextrins according to the Benesi-Hildebrand equation. The binding affinity was larger in NOS-M-β-CD (5.9 (± 0.66) × 103 M- 1) than NOS-β-CD (3.7 (± 0.22) × 103 M- 1) complex. The fluorescence emission band of NOS at 408nm was quenched when NOS was complexed with β-CD, and enhanced in the presence of M-β-CD, while the shoulder at 350nm was enhanced selectively when NOS was complexed with M-β-CD. The fluorescence quenching of NOS with β-CD showed a negative deviation from the Stern-Volmer. The thermodynamic parameters have been estimated with the help of the Van't Hoff equation in different temperatures, and a dynamic mechanism was proposed for quenching. Also, both ΔH and ΔS have positive values thus the main interactions result in hydrophobic forces. Moreover, the negative value of ΔG indicates that the bonding process is spontaneous. 1H NMR chemical shift changes were observable for NOS and both CDs protons due to the chemical environment changes of some nuclei upon complexation. The molecular docking results revealed that the 1:1 inclusion complex possesses a good molecular shape complementarity score for their most probable structures, and indicated that the M-β-CD inclusion system gave the higher complexation efficiency. The binding energy values for β-CD and M-β-CD were determined to be -6.7 and - 9.5kcal/mol, respectively. These findings suggest the same as the result of experimental tests that the NOS-M-β-CD complex is more stable than the NOS-β-CD complex.

Effect of transition metal (M=Cr, Mn, Fe, Co) doping on catalytic combustion of chlorobenzene over Ce − Y composite oxide

Transition metal (Cr, Mn, Fe, Co)-doped CeYOx catalysts were prepared by a co-precipitation method and applied for chlorobenzene elimination. Metal doping caused significant changes in physical properties and chemical environment of CeY solid solution. Intrinsic activity of metals and their interaction with CeY significantly improved the redox performance and oxygen mobility, thus enhancing the catalytic activity and chlorine poisoning resistance. The enhanced concentration and mobility of reactive oxygen can effectively control chlorinated by-products. MnCeYOx can achieve 90 % chlorobenzene conversion at 235 °C, attributing to the promotion of the redox dynamic cycle by the enhanced mobility of active oxygen.

Tunable and responsive photonic bio‐inspired materials and their applications

AbstractBio‐enabled and bio‐mimetic nanomaterials represent functional materials, which use bio‐derived materials and synthetic components to bring the better of two, natural and synthetic, worlds. Prospective broad applications are flexibility and mechanical strength of lightweight structures, adaptive photonic functions and chiroptical activity, ambient processing and sustainability, and potential scalability along with broad sensing/communication abilities. Here, we summarize recent results on relevant functional photonic materials with responsive behavior under mechanical stresses, magnetic field, and changing chemical environment. We focus on recent achievements and trends in tuning optical materials' properties such as light scattering, absorption and reflection, light emission, structural colors, optical birefringence, linear and circular polarization for prospective applications in biosensing, optical communication, optical encoding, fast actuation, biomedical fields, and tunable optical appearance.

Calcium dynamics during the growth of Agaricus bisporus: implications for mushroom development and nutrition

BackgroundAgaricus bisporus (A. bisporus) is highly valued for its nutritional benefits and delicious taste, making it one of the most widely cultivated, highest yielding, and most consumed edible mushrooms worldwide. The yield and quality of A. bisporus were affected by its culture medium and environment. Among the culture base, the precise impact of calcium on A. bisporus cultivation and the dynamic changes in calcium concentration and chemical environment during the cultivation process remain unclear. This study aims to investigate the changes in calcium content and forms during the growth of A. bisporus and their implications for mushroom growth and nutrition.ResultsThrough the analysis of samples collected during the composting phase, mycelial development phase, and A. bisporus harvesting phase, the role of calcium in the growth process of button mushrooms is revealed. During the composting phase, the calcium content remains relatively stable, suggesting a consistent calcium source in the compost. The fermentation process shows a significant decrease in carbon content and an increase in oxygen content, indicating the degradation and oxidation of organic matter. In the mycelial development phase, both the cover soil and compost experience a decrease in calcium content, with a more pronounced reduction observed in the covering soil, indicating its primary role as an energy source for enzymatic activity and metabolic processes of the mycelium. During the A. bisporus harvesting phase, the changes in calcium, carbon, and oxygen content become less prominent, indicating a stable state of fruiting bodies growth that no longer requires a significant supply of organic matter.ConclusionsAnalysis of calcium forms reveals the presence of different calcium compounds, likely influenced by soil calcium sources, microbial activities, and mushroom metabolic byproducts. Calcium plays a crucial regulatory role in the growth and quality of A. bisporus. This study provides valuable insights into the significance of calcium in A. bisporus growth and offers theoretical guidance for optimizing mushroom production and quality improvement.Graphical

N-methyldiethanolamine (MDEA) as an effective CO2 absorbent for direct air capture (DAC) in cement-based materials

The escalating release of CO2 into the atmosphere has turned the matter of global warming into a pressing issue. Therefore, direct air capture (DAC - capturing CO2 from the environment) using buildings and infrastructure made of cement-based materials as “synthetic trees” could be an effective approach, given the growing urbanization trend. This study proposed a new technique to use N-methyldiethanolamine (MDEA) in cement-based materials to sequestrate CO2 from the environment. It has significant potential and flexibility compared to existing CO2 capture technologies, particularly given the limitations of CO2 mineralization in cement-based materials with slow kinetics. Furthermore, this study examined the resulting microstructural changes and reaction mechanisms of each hydrated phase, such as Ca(OH)2, calcium-silicate-hydrate (C-S-H), and hydrated cement, due to the addition of MDEA after carbonation. The study also investigated the effect of different percentages of amine on the carbonation of Ca(OH)2 under accelerated conditions, followed by the natural carbonation of cement paste coarse particles. The results showed that a 10% MDEA of water volume is optimal for CO2 capture in cement-based materials. Beyond this percentage, MDEA loss on the surface of solid particles was observed by thermogravimetric analysis (TGA). The study also examined the changes in microstructure, chemical environment, pH, and calcite formation in the cement paste samples with one side exposed to accelerated carbonation. MDEA increased calcite formation by 1.5–2 times compared to the samples that did not contain MDEA. Additionally, aragonite and calcite were formed when MDEA was present, whereas the samples without MDEA only formed calcite.

Discrepant diversity patterns and function of bacterial and fungal communities on an earthquake-prone mountain gradient in Northwest Sichuan, China.

Patterns of microbial diversity on elevational gradients have been extensively studied, but little is known about those patterns during the restoration of earthquake-fractured alpine ecosystems. In this study, soil properties, soil enzyme activities, abundance and diversity of soil bacterial and fungal communities at four positions along a 2.6-km elevational gradient in the Snow Treasure Summit National Nature Reserve, located in Pingwu County, Southwest China. Although there were no significant changes in the soil chemical environment, bacterial and fungal communities were significantly different at different elevations. The overall fungal community presented an N-shaped diversity pattern with increasing elevation, while bacterial diversity decreased significantly with elevation. Changes in microbial diversity were associated with soil phosphorus, plant litter, and variations in dominant microbial taxa. Differences in enzyme activities among elevations were regulated by microbial communities, with changes in catalase and acid phosphatase activities mainly controlled by Acidobacteria and Planctomycetaceae bacteria, respectively (catalase: p < 0.001; acid phosphatase: p < 0.01), and those in β-glucosidase, sucrase, and urease activities mainly controlled by fungi. The β-glucosidase and sucrase were both positively correlated with Herpotrichiellaceae, and urease was positively correlated with Sebacinaceae (p < 0.05). These findings contribute to the conservation and management of mountain ecosystems in the face of changing environmental conditions. Further research can delve into the specific interactions between microbial communities, soil properties, and vegetation to gain deeper insights into the intricate ecological dynamics within earthquake-prone mountain ecosystems.

Imaging the dynamic influence of functional groups on metal-organic frameworks

Metal-organic frameworks (MOFs) with different functional groups have wide applications, while the understanding of functionalization influences remains insufficient. Previous researches focused on the static changes in electronic structure or chemical environment, while it is unclear in the aspect of dynamic influence, especially in the direct imaging of dynamic changes after functionalization. Here we use integrated differential phase contrast scanning transmission electron microscopy (iDPC-STEM) to directly ‘see’ the rotation properties of benzene rings in the linkers of UiO-66, and observe the high correlation between local rigidity and the functional groups on the organic linkers. The rigidity is then correlated to the macroscopic properties of CO2 uptake, indicating that functionalization can change the capability through not only static electronic effects, but also dynamic rotation properties. To the best of our knowledge this is the first example of a technique to directly image the rotation properties of linkers in MOFs, which provides an approach to study the local flexibility and paves the way for potential applications in capturing, separation and molecular machine.

Off-Stoichiometric Restructuring and Sliding Dynamics of Hexagonal Boron Nitride Edges in Conditions of Oxidative Dehydrogenation of Propane.

Boron-containing materials, such as hexagonal boron nitride (h-BN), recently shown to be active and selective catalysts for the oxidative dehydrogenation of propane (ODHP), have been shown to undergo significant surface oxyfunctionalization and restructuring. Although experimental ex situ studies have probed the change in chemical environment on the surface, the structural evolution of it under varying reaction conditions has not been established. Herein, we perform global optimization structure search with a grand canonical genetic algorithm to explore the chemical space of off-stoichiometric restructuring of the h-BN surface under ambient as well as ODHP-relevant conditions. A grand canonical ensemble representation of the surface is established, and the predicted 11B solid-state NMR spectra are consistent with previous experimental reports. In addition, we investigated the relative sliding of h-BN sheets and how it influences the surface chemistry with ab initio molecular dynamics simulations. The B-O linkages on the edges are found to be significantly strained during the sliding, causing the metastable sliding configurations to have higher reactivity toward the activation of propane and water.

Achieving overall rejection of pharmaceuticals and personal care products of different polarities by controlling interlayer charging environment of graphene oxide membrane using carbon quantum dots

To realize overall rejection of numerous pharmaceuticals and personal care products (PPCPs) with varieties in hydrophilicity (dissolubility giving either negative or positive charges and non-dissolubility) and hydrophobicity, a diverse interlayer charging environment was controlled by intercalating two-dimensional carbon quantum dot (CQD)-like nanoparticles into graphene oxide membrane (GOM). It was found that ethylenediamine-added sucrose-derived CQD with a positively charged surface in aqueous solution is appropriate for such a purpose because of the strong electrostatic attraction by the graphene oxide (GO) surface of opposite charge. The CQD contains plenty of pyridine groups of stronger basicity and pyrrole groups of weaker basicity, which contribute majorly to anchoring the CQD onto GO surface and to donating positive charges in GOM interlayer, respectively. This unique membrane design strategy allows coexisting of both negatively and positively charged groups in a slightly expanded hydrophilic interlayer space of GOM. As the result, not only rejections were promoted for the negatively dissociative PPCPs (from 77 % to all more than 86%) and neutral PPCPs (from 25 % to all more than 56%) but also rejections of the positively dissociative PPCPs became remarkable (from null to all more than 56%). The research result provides a promising methodology of changing chemical environment of a simpler membrane material other than nanofiltration or reverse osmosis to achieve an all-together rejecting effect toward PPCPs of various polarities.

Study on reactive dyeing in a sustainable nonaqueous medium dyeing system by X-ray electron spectroscopy

In the nonaqueous medium dyeing system (decamethylcyclopenta siloxane; D5), the bonding between cotton fiber and reactive dye may be influenced by the dyeing medium. To evaluate the dyeing performance of reactive dye in the D5 dyeing system, the fixing of reactive dyes with different structures was studied. Before and after dyeing, the chemical environment of cotton fiber was investigated by X-ray electron spectroscopy, and compared with the spectroscopic method. Compared with traditional reactive dyeing, the color depth of the dyed cotton fabrics and the final fixation of dyes are much higher in the D5 dyeing system. The elements of the cellulose fiber surface are changed after dyeing. Especially for N element, its content is increased after dyeing. After 30 minutes, the final fixation of reactive dye is about 80% by analyzing the account of N. Compared with the undyed cellulose fiber, the peak area of C–C or C–H is gradually increased after dyeing, but the proportion of C–O is decreased with the fixing time. The proportion of O–C–O is not changed much with the fixation time. Therefore, the C–C or C–H chemical environment on the cellulose fiber surface will be changed after dyeing. Therefore, the bonding of dyes and fibers can be analyzed through the change of the C1s chemical environment or the amount of N element before and after dyeing. This investigation successfully developed a method which could evaluate the fixation process in the D5 dyeing system.

Exogenous Streptomyces spp. benefit naked oat growth under dry farming conditions by modifying rhizosphere bacterial communities

Manipulation of rhizosphere microbiota is an effective strategy to facilitate crop growth in dry farming systems. Actinobacteria, such as Streptomyces spp., have the potential to alleviate plant damage induced by drought stress. However, whether exogenous actinobacteria can promote naked oat (Avena nuda L.) growth in drylands by reshaping rhizosphere bacterial community structure is still unclear. This study evaluated the effects of S. albidoflavus T4 and S. pactum Act12 on the growth and yield of naked oat through a two-year field experiment conducted in Taigu, Shanxi Province, China. Streptomyces-mediated shifts in rhizosphere bacterial diversity and community composition were analyzed based on 16S ribosomal RNA gene sequencing. Both T4 and Act12 inoculation improved plant growth and grain yield by 21.5 %–27.4 % compared with the uninoculated control. Despite no significant changes in the alpha diversity of rhizosphere bacteria, their community composition varied in different patterns following inoculation. In T4-treated soils, there were increased proportions of Chloroflexi (rare phylum), Stenotrophomonas (abundant genus), and Acidovorax (moderate genus), along with a decreased proportion of Polycyclovorans (moderate genus). These differential taxa were closely related to increased soil available phosphorus and potassium contents as well as alkaline phosphatase activity, thereby contributing to plant growth. Act12-treated soils showed increased proportions of Lachnospiraceae_NK4A136 (abundant genus), Pantoea (rare genus), and Kluyvera (rare genus), in contrast to the decreasing trend of Microvirga (moderate genus). These differential taxa were mainly associated with enhanced soil sucrase and leaf catalase activities, which indirectly increased plant biomass and grain yield. The findings demonstrate that inoculation with S. albidoflavus T4 and S. pactum Act12 conveys benefits to naked oat growth under dry farming conditions as an indirect consequence of alterations in key taxa abundance in rhizosphere microbiota coupled with changes in soil chemical environment and plant antioxidant activity.

Sodium Salt of Partially Carboxymethylated Sodium Alginate-Graft-Poly(Acrylonitrile): II Superabsorbency, Salt Sensitivity and Swelling Kinetics of Hydrogel, H-Na-PCMSA-g-PAN.

The water absorption measurements of a novel superabsorbent anionic hydrogel, H-Na-PCMSA-g-PAN, has been reported first time in water with a poor conductivity, 0.15 M saline (NaCl, CaCl2, and AlCl3) solutions, and simulated urine (SU) solutions at various times. The hydrogel has been prepared by the saponification of the graft copolymer, Na-PCMSA-g-PAN (%G = 316.53, %GE = 99.31). Results indicated that as compared to the swelling capacity values evaluated in water with a poor conductivity, the ability of the hydrogel to swell in various saline solutions with the same concentration is significantly reduced at all different durations. The swelling tends to be Na+ > Ca2+ > Al3+ at the same saline concentration in the solution. Studies of the absorbency in various aqueous saline (NaCl) solutions also revealed that the swelling capacity decreased as the ionic strength of the swelling medium rose, which is consistent with the experimental results and Flory's equation. Furthermore, the experimental results strongly suggested that second-order kinetics governs the swelling process of the hydrogel in various swelling media. The swelling characteristics and equilibrium water contents for the hydrogel in various swelling media have also been researched. The hydrogel samples have been successfully characterized by FTIR to show the change in chemical environment to COO- and CONH2 groups after swelling in different swelling media. The samples have also been characterized by SEM technique.

Mechanism of ultrasonic cavitation to improve the effect of siderite on quartz flotation

In order to effectively eliminate the effect of fine carbonate minerals on quartz flotation, the influence of fine siderite on quartz flotation was studied as well as the mechanism or role of ultrasonic treatment in the process. The results of adsorption capacity measurement and flotation solution chemical calculation show that fine siderite and its dissolved components have a great influence on the collector consumption and the surface properties of quartz. In addition, SEM, EDS and XPS analysis were used to study the surface morphology and chemical environment changes of quartz with and without ultrasonic treatment. The results of flotation test show that the recovery of quartz increase from 38.79% to 58.38% under the condition that ultrasonic time was 0.5 min and ultrasonic power was 200 W. The mechanical effect caused by ultrasonic cavitation can clean the quartz surface to a certain extent and increase its active sites, thus improving the floatability of quartz.

Bridging Colloidal and Electrochemical Nanoparticle Growth with In Situ Electrochemical Measurements.

ConspectusProspective applications involving the electrification of industrial chemical processes and electrical energy to chemical fuels interconversion as part of the energy transition to renewable energy sources have led to an increasing need for highly tailored nanostructures immobilized on electrode surfaces. Control of surface facet structure across material compositions is of particular importance for ensuring performance in such applications. Colloidal methods for producing shaped nanoparticles in solution are abundant, particularly for noble metals. However, significant technical challenges remain with respect to rationally designing syntheses for the novel compositions and morphologies required to sustainably enable the above technological advances as well as in developing methods for uniformly and reproducibly dispersing colloidally synthesized nanostructures on electrode surfaces. The direct synthesis of nanoparticles on electrodes using chemical reduction approaches remains challenging, though recent advances have been made for certain materials and structures. Electrochemical nanoparticle synthesis─where an applied current or potential instead of a chemical reducing agent drives the redox chemistry of nanoparticle growth─is poised to play an important role in advancing the fabrication of nanostructured electrodes. Specifically, this Account focuses on the colloidal-inspired design of electrochemical syntheses and the interplay between colloidal and electrochemical approaches in terms of understanding the fundamental chemical reaction mechanisms of nanoparticle growth. An initial discussion of the development of electrochemical particle syntheses that incorporate colloidal synthetic tools highlights the promising emergent capabilities that result from blending these two approaches. Furthermore, it demonstrates how existing colloidal syntheses can be directly translated to electrochemical growth on a conductive surface using real-time electrochemical measurements of the chemistry of the growth solution. Measuring the open circuit potential of a colloidal synthesis over time and then replicating that measured potential during electrochemical deposition leads to the formation of the same nanoparticle shape. These in situ open circuit and chronopotentiometric measurements also give fundamental insight about the changing chemical environment during particle growth. We highlight how these time-resolved electrochemical measurements, as well as correlated spectroelectrochemical monitoring of particle formation kinetics, enable the extraction of information regarding mechanisms of particle formation that is difficult to obtain using other approaches. This information can be translated back into colloidal synthesis design via a directed, intentional approach to synthetic development. We additionally explore the added flexibility of synthetic design for methods involving electrochemically driven reduction as compared to the use of chemical reducing agents. The Account concludes with a brief perspective on potential future directions in both fundamental studies and synthetic development enabled by this emerging integrated electrochemical approach.

Changes in soil biological and chemical environment during wheat growth stages under nitrogen and straw management practices in rice-wheat system

Crop residues are a neglected source of sustainable agriculture since they are produced in large quantities, yet farmers frequently burn them. The purpose of this study was to assess the effects of nitrogen (N) application rate and residue management strategies for wheat production on changes in soil enzyme activity, microbial count, and chemical properties at various growth stages. Different combinations of N fertilizer rates, tillage, and residue management practices for wheat were investigated in split-plot design. The main plots were assigned for two N applications rates (N75 and N100, 75 and 100% recommended dose of N, whereas the subplots were assigned for seven treatments as: (1) conventional tillage (CT)-rice residue removed (R), (2) sowing with rotoseeder (RS)-R, (3) sowing with Happy Seeder (HS)+ loose rice residue removed (R50), (4) HS + 100% rice residue retained (R100), (5) RS + R50, (6) RS + R100, (7) CT + R100. The results revealed that N100 and HS + R100 increased wheat yield, chemical and biochemical properties, with the exception of polyphenol oxidase and peroxidase. All biochemical characteristics were greater during vegetative and reproductive growth stages than before seeding and harvesting. Dehydrogenase, polyphenol oxidase, and flourescein diacetate were found as the most sensitive indicators using principle component analysis.

Influence of local chemical environment and external perturbations of porphyrins on surfaces

Porphyrins and tetrapyrroles play crucial roles in biological processes such as photosynthesis and molecular transport. These nature-based molecules have found application in artificial systems, such as sensing, catalysis, and 2D/3D networks. They are ideal building blocks due to their chemical diversity, stability, and ability to self-assemble on surfaces. Derivatization of the peripheral positions allows for the rational design of magnetic, catalytic, and photochemical properties. Due to this, porphyrins have been used in a variety of natural and artificial systems such as photodynamic therapies and dye-sensitized solar cells. Recently, much work and attention have focused on using specific porphyrin and molecular relatives for molecular electronics due to their robust nature, functionality, and synthesis. The focus of this review is to summarize the mechanisms that affect the internal structure and properties of the molecules and how changes in the local chemical environment alter the electronic properties of the porphyrin. We review the current state of the literature concerning the intermolecular and surface-adsorbate interactions that dictate self-assembly. We will assess the effects that molecule-molecule and molecule-substrate interactions play on the molecule’s properties and the effects that external forces have on the molecular properties. The goal of this review is to dissect the mechanisms responsible for the unique properties that arise from porphyrinic systems adsorbed on surfaces.