Applications of photocatalytic titanium dioxide-based nanomaterials in sustainable agriculture

Photocatalytic materials are attracting attention as emerging resources for agricultural applications. This timely review assesses the current developments in the use of biocompatible titanium dioxide (TiO₂)-based photocatalytic nanomaterials (TiO₂-PN) as models to unravel agricultural growth, harvest, and post-harvest problems. Such developments can lead to technological innovations aimed at addressing the pressing global environmental challenges faced by farming. TiO₂-PN have been used as antimicrobial, growth-regulating, and fertilizer-like agents. The promising agricultural research applications of TiO₂-PN are highlighted along with a discussion of the main challenges that will need to be overcome to fully understand the roles of TiO₂-PN in the sustainable and productive exploitation of land and water for agricultural applications under natural conditions. In particular, rhizosphere internalization, translocation, and plant bioaccumulation pathways of photocatalytic materials from environmental exposition are outlined to illustrate the effect of TiO₂ on the agricultural cycle. Nanotoxicology and regulations are also discussed to illustrate the importance of biocompatibility and green synthesis of nanomaterials for safe use in real applications. This overview is focused on motivating and intensifying our understanding of on-site agricultural studies. Complementary biological approaches and structural damage observed by biological transmission electron, scanning electron, and optical microscopies should accelerate the practical contribution of TiO₂-PN to sustainable agriculture in conjunction with plant factories and plasma nitrogen fixation technology. Loadings below 10 μg/L of TiO₂-PN with a size of 40 nm benefit seed germination and root elongation as well as partially suppressing metal root translocation. However, only approximately 5% of current studies were carried out in real agricultural settings.     

A review of recent advances in catalytic combustion of VOCs on perovskite-type catalysts

Along with the rapid development of industry, VOCs gradually move into the spotlight, and now become a kind of harmful environmental pollutants that cannot be overlooked. This paper introduces the hazards of VOCs and the common catalytic combustion catalysts, noble metal catalysts and non-noble metal catalysts, for the elimination of VOCs. Perovskite catalysts, as one of the non-noble catalysts, play an important role in the field of catalytic combustion in recent years. According to the classification of elements doping in perovskites, the research achievements in the past five years were analyzed and reviewed. In addition, this paper also analyzes and elaborates the reaction kinetics and QSAR/QSPR models for the introduction of structural properties and reaction mechanisms.     

A simple,rapid and sensitive method based on modified multiwalled carbon nanotube for preconcentration and determination of lead ions in aqueous media in natural pHs

In this study, multiwalled carbon nanotube (MWCNT) was modified by the pyridine group using a silane agent and characterized by infrared spectroscopy (IR), thermal analysis (TG/DTA), and elemental analysis (CHN) and scanning electron microscopy (SEM). The application of this sorbent was investigated in determination of lead ions in aqueous samples, using flame atomic absorption spectrometry (FAAS). Through this study, different parameters such as pH and sample flow rate on adsorption process and eluent concentration, volume and flow rate were optimized. The limit of detection (LOD), the relative standard deviation and the recovery of the method were 2 ng mL^?1, 1.3% and 99.7%, respectively. Two standard reference materials (NIST 1571 and NIST 1572) were used to verify accuracy of this method. Finally, the sorbent was successfully applied for extraction and determination of low levels of Pb(II) ions in aqueous samples.     

Development and Validation of High-Throughput Bioanalytical Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) Method for the Quantification of Newly Synthesized Antitumor Carbonic Anhydrase Inhibitors in Human Plasma

In the present study, a sensitive and fully validated bioanalytical high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed for the quantitative determination of three newly synthesized carbonic anhydrases inhibitors (CAIs) with potential antitumor activity in human plasma. The analytes and the internal standard (IS) were extracted using 1.5 mL acetonitrile from only 450 µL aliquots of human plasma to achieve the desired protein precipitation. Chromatographic separations were achieved on Phenomenex Kinetex^® C₁₈ column (100 × 4.6 mm, 2.6 µm) using a binary gradient elution mode with a run time of less than 6 min. The mobile phase consisted of solvent (A): 0.1% formic acid in 50% methanol and solvent B: 0.1% formic acid in acetonitrile (30:70, v/v), pumped at a flow rate of 0.8 mL/min. Detection was employed using triple quadrupole tandem mass spectrometer (API 3500) equipped with an electrospray ionization (ESI) source in the positive ion mode. Multiple reaction monitoring (MRM) mode was selected for quantitation through monitoring the precursor-to-parent ion transition at m/z 291.9 → 173.0, m/z 396.9 → 225.1, m/z 388.9 → 217.0, and m/z 146.9 → 91.0 for AW-9a, WES-1, WES-2, and Coumarin (IS), respectively. Linearity was computed using the weighted least-squares linear regression method (1/x²) over a concentration range of 1–1000, 2.5–800, and 5–500 ng/mL for AW-9a, WES-1, and WES-2; respectively. The bioanalytical LC-MS/MS method was fully validated as per U.S. Food and Drug Administration (FDA) guidelines with all respect to linearity, accuracy, precision, carry-over, selectivity, dilution integrity, and stability. The proposed LC-MS/MS method was applied successfully for the determination of all investigated drugs in spiked human plasma with no significant matrix effect, which is a crucial cornerstone in further therapeutic drug monitoring of newly developed therapeutic agents.     

Mass spectrometry combined with affinity probes for the identification of CP4 EPSPS in genetically modified soybeans

Sample preparation methods used for genetically modified organisms (GMOs) analysis are often time consuming, require extensive manual manipulation, and result in limited amounts of purified protein, which may complicate the detection of low‐abundance GM protein. A robust sample pretreatment method prior to mass spectrometry (MS) detection of the transgenic protein (5‐enolpyruvylshikimate‐3‐phosphate synthase [CP4 EPSPS]) present in Roundup Ready soya is investigated. Liquid chromatography‐multiple reaction monitoring tandem MS (nano LC‐MS/MS‐MRM) was used for the detection and quantification of CP4 EPSPS. Gold nanoparticles (AuNPs) and concanavalin A (Con A)‐immobilized Sepharose 4B were used as selective probes for the separation of the major storage proteins in soybeans. AuNPs that enable the capture of cysteine‐containing proteins were used to reduce the complexity of the crude extract of GM soya. Con A‐sepharose was used for the affinity capture of β‐conglycinin and other glycoproteins of soya prior to enzymatic digestion. The methods enabled the detection of unique peptides of CP4 EPSPS at a level as low as 0.5% of GM soya in MRM mode. Stable‐isotope dimethyl labeling was further applied to the quantification of GM soya. Both probes exhibited high selectivity and efficiency for the affinity capture of storage proteins, leading to the quantitative detection at 0.5% GM soya, which is a level below the current European Union's threshold for food labeling. The square correlation coefficients were greater than 0.99. The approach for sample preparation is very simple without the need for time‐consuming protein prefractionation or separation procedures and thus presents a significant improvement over existing methods for the analysis of the GM soya protein.     

An analysis of overlapping Schwarz method for a weakly coupled system of singularly perturbed convection-diffusion equations

In this article, we have developed an overlapping Schwarz method for a weakly coupled system of convection-diffusion equations. The method splits the original domain into two overlapping subdomains. A hybrid difference scheme is proposed in which on the boundary layer region, we use the central finite difference scheme on a uniform mesh, whereas on the nonlayer region, we use the mid-point difference scheme on a uniform mesh. It is shown that the numerical approximations converge in the maximum norm to the exact solution. We have proved that, when appropriate subdomains are used, the method produces almost second-order convergence. Furthermore, it is shown that two iterations are sufficient to achieve the expected accuracy. Numerical examples are presented to support the theoretical results. The main advantage of this method used with the proposed scheme is that it reduces iteration counts very much and easily identifies in which iteration the Schwarz iterate terminates.     

Regularity and Rigidity for Nonlocal Curvatures in Conformal Geometry

In this paper, we will explore the geometric effects of conformally covariant operators and the induced nonlinear curvature equations in certain nonlocal nature. Mainly, we will prove some regularity and rigidity results for the distributional solutions to those equations.     

Recent trends in capillary and micro-chip electrophoretic instrumentation for field-analysis

Technical advances in the development of field-deployable capillary and microchip electrophoretic instruments and reports of their deployment between 2013 and 2017 were reviewed. Strategies and considerations in the design of the injection, separation and detection hardware, chemistry and associated infrastructure were discussed from an in-field perspective, with portability, robustness and automation/“ease of use” featuring as key requirements. Integration of functionality is important for adequate in-field performance. Progress was made towards the use of multiple channel devices for increased throughput and/or resolving power, mixing devices for on-line/in-line sample derivatization, battery operation and temperature control. The strengths and weaknesses of the various approaches described in the literature are discussed from the perspective of in-field operation. An overview of the applications of the field electrophoretic instruments is provided, including environmental science and planetary investigation.