Carbon Disulfide Research Articles

Rapid cycling and emission of volatile sulfur compounds in the eastern Indian Ocean: Impact of runoff inputs and implications for balancing atmospheric carbonyl sulfide budget

Volatile sulfur compounds, such as dimethyl sulfide (DMS), carbonyl sulfide (OCS), and carbon disulfide (CS2), significantly influence atmospheric chemistry and climate change. Despite the oceans being an important source of these sulfides, the limited understanding of their biogeochemical cycles in seawater introduces considerable uncertainties in quantifying their oceanic emissions and assessing atmospheric OCS budgets. To address this issue, we conducted a comprehensive field survey in the tropical eastern Indian Ocean (EIO) to examine the spatial distributions, source-sink dynamics, and sea-air exchange fluxes of marine DMS, OCS, and CS2. Our study indicates that nutrients, organic matter, and freshwater input from terrestrial runoff significantly affect most of the source-sink processes of these sulfides in the Bay of Bengal and even the tropical EIO. The resulting sulfide accumulation in seawater combined with high wind speeds establishes the tropical EIO as a considerable direct and indirect atmospheric OCS source. These insights underscore the potentially critical role of marine environments influenced by runoff in contributing to the atmospheric OCS budget. However, by integrating these results with previous field surveys, we believe that actual OCS emissions from tropical oceans exceed some bottom-up box-model simulations, yet fall significantly below those predicted by top-down models, still insufficient to bridge the atmospheric OCS source gap. Our detailed examination of source-sink dynamics offers deeper insights into the marine sulfur cycle and has potential implications for refining future box-models, thus mitigating uncertainties in estimating marine sulfur emissions.

Research on Compatibility of Packaging Materials of High-Risk Cephalosporin Powder Injection and Establishment of Indicator Component Evaluation Method

aims: To establish a GC-MS method for the determination of extractable substances in the stoppers of Ceftriaxone sodium bottles for injection; To establish a HPLC method for the determination of vulcanizing agent and antioxidant in Ceftriaxone sodium for injection bottle stopper and to analyze the correlation between the volatile substances of rubber stopper and the clarity of solution. objective: To establish a GC-MS method for the determination of extractable substances in the stoppers of Ceftriaxone sodium bottles for injection; To establish a HPLC method for the determination of vulcanizing agent and antioxidant in Ceftriaxone sodium for injection bottle stopper and to analyze the correlation between the volatile substances of rubber stopper and the clarity of solution. method: GC-MS method was used with capillary column Rtx-5MS (30.0 m×0.25 mm, 0.25 µm), the carrier gas was He at the flow rate of 1.8mL·min-1, the temperature of injection port was 200 ℃, shunt ratio was 10∶l, the column temperature was programmed temperature(initial column temperature was 40 ℃ and kept for 15 min, and with the speed of 10 ℃ upping to 100 ℃ and kept for 2 min, and with the speed of 25 ℃ upping to 230 ℃ and kept for 10 min), the interface temperature was 250 ℃, and the scanning range was from 29 to 600(m·z-1), and the volatile substances were using full scan. An inertsil ODS-3 column(250 mm×4.6 mm, 5 µm) was used for the HPLC analysis. The mobile phase A consisted of water containing 0.04% trifluoroacetic and the mobile phase B consisted of acetonitrile containing 0.04% trifluoroacetic acid, the gradient elution was used and the flow rate was set as 1.0 mL·min-1. The column temperature was 30 ℃, the detection wavelength was 210 nm and the injection volume was 10 µL. result: Antioxidant BHT(264), silicone oil and other organic compounds in rubber stopper permeated and migrated to the sample with acceleration time by GC-MS. A good linearity was observed over the range of 0.5-100 μg·mL-1(r＞0.999). The detection limits of vulcanizing agent and antioxidant were about 0.03 μg·mL-1, and the quantitation limits were about 0.1 μg·mL-1. The average recoveries (low, medium and high) of antioxidant (168, 264, 330, 1076, 1010) and vulcanizing agents (carbon disulfide, sulfur) were between 90.0% and 110.0%, and the corresponding RSD were less than 5% (n=9) by adding standard recovery experiments. The stability test showed that the antioxidant and the vulcanizing agent solution had good stability and was stable within 24 hours. conclusion: the GC-MS/HPLC method can be used for the quality control of rubber stopper of cefuroxime Sodium for Injection.The compatibility study and comprehensive evaluation system of Ceftriaxone sodium for injection packaging materials have been initially formed.

Heavy metal ions in polluted water removable by synthesising a new compounds for dithiocarbamate derivatives

Metal ion poisoning in water and industrial effluents threatens ecosystems and human health. The development of efficient metal ion removal technologies has garnered attention in recent years. This work synthesizes and characterizes dithiocarbamate complexes as metal ion scavengers. Used to make dithiocarbamate ligands. Different metal salts were added to carbon disulfide and the proper amines to initiate substitution reactions. The complexes were characterized using FTIR, UV-Vis, mass spectroscopy, 13C-, 1H-NMR, magnetic susceptibility, melting point, and electrical conductivity molar EC. Data from spectroscopy and analysis indicate the development of two-type macrocyclic complexes with the formula [M(L)]2, where M = FeII, CoII, and ZnII ions. Tetrahedral geometries around the metal core and the second general formula [M(L)(H2O)2]2, where M = MnII, NiII, CuII, suggested octahedral structures. Heavy water pollution has been removed using this essential ligand. Metal ion scavenging of 96–98% was possible with the produced dithiocarbamate complexes. This work developed unique and efficient strategies for metal contamination removal from aquatic settings, promising environmental remediation and human health protection. Optimizing synthesis conditions and scaling up operations are needed to fully use these compounds in real-world applications. KEY WORDS: Dithiocarbamate ligand, Transition metal complexes, Spectral characterization, Coordination chemistry, Dithiocarbamate complexes, Scavenger heavy metal ions Bull. Chem. Soc. Ethiop. 2024, 38(6), 1583-1593. DOI: https://dx.doi.org/10.4314/bcse.v38i6.7

Hydrazides: An Important Tool for the Synthesis of 1,3,4-Oxadiazole

Abstract: Hydrazides, derivatives of hydrazine, are widely used in pharmaceuticals, polymers, dyes, herbicides, and as chemical preservatives. A notable application is in synthesizing 1,3,4-oxadiazole, an important aromatic compound with a five-membered heterocyclic ring containing two nitrogen atoms and one oxygen atom. Among the four oxadiazole isomers, 1,3,4-oxadiazole is the most significant, used in drug discovery, pharmaceuticals, and dyes. It is synthesized from various substituted hydrazides or hydrazones using reagents like copper, cobalt, cerium, phosphorus oxychloride, mercury oxide, potassium iodide, triflic anhydride, and carbon disulfide. This study reviews the synthesis methods of 1,3,4-oxadiazole, highlighting the advantages and disadvantages of different catalysts and conditions, providing useful insights for researchers.

A Greener Way of Making Cellulose Clothing

Cotton is the world's most demanding non-food crop. Cotton grows in arid countries such as India and China. However, its production consumes an enormous 250 billion tons of water annually, amplifying water scarcity. Cellulose, found in plants like wood, bamboo, and mosses, offers a sustainable alternative for textiles. Traditionally, cellulose is processed into textiles using the viscose method, which involves carbon disulfide. This process releases hydrogen sulfide, harmful to aquatic life and human health, and carbon disulfide, a hazardous pollutant affecting the reproductive system and vision. Many research groups have proposed an alternative method, which involves dissolving cellulose in dimethyl sulfoxide (DMSO) and Diazabicyclo[5.4.0]undec-7-ene (DBU) under 1 atm of CO2. DBU, with a pKaH ~ 12, deprotonates cellulose’s hydroxyl groups forming a DMSO-soluble cellulose carbonate complex that can be spun into filaments. However, DBU is costly, hazardous, and prone to hydrolysis, leading to byproducts. The objective of the research was to find a more environmentally friendly, less toxic, and cost-effective base for cellulose dissolution. Two tertiary amines, triethylamine (pKaH~9) and tripropylamine (pKaH~10.7), were tested. Due to its low basicity triethylamine failed to dissolve cellulose even under high CO2 pressure (up to 50 bar), resulting in a cloudy solution. Tripropylamine is insoluble in DMSO, therefore resulting in a phase separation of a tripropylamine layer and cellulose/DMSO layer. Additionally, 2,2,6,6-tetramethyl-piperidine was also tested at high CO2 pressure (up to 50 bar), but a biphasic solution was formed at 10 bar . This indicates that the protonated form of the base does not dissolve in DMSO. Ultimately, no alternative base was found to be sufficiently basic to deprotonate the hydroxyl groups on cellulose and promote dissolution, even at high pressure.

Synthesis, molecular docking, and anti-breast cancer study of 1-H-indol-3-Carbohydrazide and their derivatives

A prominent heterocyclic system found in medications and natural goods is indoles. Due to the significance of this important ring system, a fresh batch of unique indole derivatives was created using indole carbohydrazide. The triazole moiety of indole derivative (3) is produced by reacting carbohydrazide with carbon disulfide in alkaline conditions, followed by hydrazine treatment. In addition to synthesizing additional derivatives, indole-bearing triazole (3) was condensed with aromatic aldehydes to create the indole derivatives (4a–c). Mass spectra, 1HNMR, 13CNMR, and infrared spectroscopy were used to diagnose all produced derivatives. An MTT assay was employed to test the derivatives against MCF-7 cells. The findings demonstrated the inhibitory action of compounds 5a and 5b, with IC50 values of 42.6 ± 0.33 µM and 27.3 ± 0.28, respectively. Affinity energy and the interaction between the investigated chemicals and receptor (CDK4 ID: 2w96) were ascertained by studying molecular docking. The chemical structure-physicochemical-pharmacokinetic relationship provides useful insight for medicinal chemists to design indole-triazole derivatives with acceptable drug-like and pharmacokinetic properties.

Metal-insulator-metal plasmonic sensor utilizing grating-defect waveguide and cavities for temperature sensing and biological applications

This paper proposes a novel plasmonic temperature and refractive index (RI) sensor that utilizes a Metal-Insulator-Metal (MIM) waveguide with two neighboring hexagonal cavities working based on Surface Plasmon Resonance (SPR). The study demonstrates that the structural parameters, including coupling distance and the number of gratings, have a substantial influence on both Full Width at Half Maximum (FWHM) and the transmission spectrum. The findings of this study demonstrated a maximum temperature sensitivity of 0.91 nm.°C−1 for carbon disulfide and a corresponding maximum temperature figure of Merit (FoM) of 0.0180 °C−1 for chloroform. The RI-sensitivity (RIS) of this sensor is found to be 1147.22 nm per RI unit (RIU) as well as its FoM is 37.1 RIU−1. Furthermore, the sensor exhibits the ability to quantify blood glucose concentration with a maximum sensitivity of 0.136 nm.g−1.L and measure blood plasma concentration with a maximum sensitivity of 0.211 nm.g−1.L. This sensor differentiates the RI between healthy and cancer cells and can be utilized to identify both healthy red blood cells and those infected with malaria. Adding gratings to the waveguide and within the hexagonal cavities has a significant impact on the transmission intensity. The proposed plasmonic sensor can be used in optoelectronics, cancer cell sensors and photonic circuits.

Secondary parkinsonism associated with focal brain lesions.

Focal imaging abnormalities in patients with parkinsonism suggest secondary etiology and require a distinctive clinical approach to diagnosis and treatment. We review different entities presenting as secondary parkinsonism associated with structural brain lesions, with emphasis on the clinical course and neuroimaging findings. Secondary parkinsonism may be due to vascular causes, hydrocephalus, space-occupying lesions, metabolic causes (including acquired hepatocerebral degeneration, diabetic uremic encephalopathy, basal ganglia calcifications, osmotic demyelination syndrome), hypoxic-ischaemic brain injury, intoxications (including methanol, carbon monoxide, cyanide, carbon disulfide, manganese poisoning and illicit drugs), infections and immune causes. The onset can vary from acute to chronic. Both uni-and bilateral presentations are possible. Rigidity, bradykinesia and gait abnormalities are more common than rest tremor. Coexisting other movement disorders and additional associated neurological signs may point to the underlying diagnosis. Neuroimaging studies are an essential part in the diagnostic work-up of secondary parkinsonism and may point directly to the underlying etiology. We focus primarily on magnetic resonance imaging to illustrate how structural imaging combined with neurological assessment can lead to diagnosis. It is crucial that typical imaging abnormalities are recognized within the relevant clinical context. Many forms of secondary parkinsonism are reversible with elimination of the specific cause, while some may benefit from symptomatic treatment. This heterogeneous group of acquired disorders has also helped shape our knowledge of Parkinson's disease and basal ganglia pathophysiology, while more recent findings in the field garner support for the network perspective on brain function and neurological disorders.

Efficient and Stable Red Perovskite Light-Emitting Diodes via Thermodynamic Crystallization Control.

Efficient and stable red perovskite light-emitting diodes (PeLEDs) demonstrate promising potential in high-definition displays and biomedical applications. Although significant progress has been made in device performance, meeting commercial demands remains a challenge in the aspects of long-term stability and high external quantum efficiency (EQE). Here, an in situ crystallization regulation strategy is developed for optimizing red perovskite films through ingenious vapor design. Mixed vapor containing dimethyl sulfoxide and carbon disulfide (CS2) is incorporated to conventional annealing, which contributes to thermodynamics dominated perovskite crystallization for well-aligned cascade phase arrangement. Additionally, the perovskite surface defect density is minimized by the CS2 molecule adsorption. Consequently, the target perovskite films exhibit smooth exciton energy transfer, reduced defect density, and blocked ion migration pathways. Leveraging these advantages, spectrally stable red PeLEDs are obtained featuring emission at 668, 656, and 648nm, which yield record peak EQEs of 30.08%, 32.14%, and 29.04%, along with prolonged half-lifetimes of 47.7, 60.0, and 43.7h at the initial luminances of 140, 250, and 270cd m-2, respectively. This work provides a universal strategy for optimizing perovskite crystallization and represents a significant stride toward the commercialization of red PeLEDs.

Developments of Pyrrolo[2,3-d]pyrimidines with Pharmaceutical Potential

: In terms of fused heterocyclic compounds, pyrrolopyrimidines, and their substituted analogs are among the most extensively explored scaffolds. Based on the location of the nitrogen atom in the pyrrole ring, pyrrolopyrimidines have different isomers. This study deals only with the pyrrolo[2,3-d]pyrimidine isomer. Several techniques are represented and discussed in this review for producing pyrrolo[2,3-d]pyrimidine derivatives. The first one is the cyclization of the pyrimidine ring on the pyrrole ring through the reaction of β-enaminonitrile, β-enaminoester or β-enaminoamide of the pyrrole ring with different bifunctional reagents such as formic acid, acetic acid, acetic anhydride, formamide, isothiocyanate, urea, thiourea, and carbon disulfide. The second technique includes cyclization of the pyrrole ring on the pyrimidine ring via the treatment of pyrimidine, aminopyrimidine, diamino-pyrimidine, or triamino-pyrimidine with different reagents such as nitroalkenes, alkynes, aldehydes, and acid chlorides. In addition, different reaction methodologies like one pot, two-step, and threestep synthetic methodologies were reported. The last technique for producing pyrrolo[2,3-d]pyrimidine derivatives is through miscellaneous reactions. This review also includes the interactions of pyrrolo[2,3- d]pyrimidines at different active centers of the pyrrole ring with different reagents to form N-alkylated, Nglycosylated, C-5, and C-6 adducts. Besides, the interactions on the pyrimidine ring to form chloro, hydrazino, and amino-imino derivatives were also discussed. The amino-imino derivatives are key intermediates for the preparation of tricyclic pyrrolotriazolopyrimidines. Finally, the pharmaceutical and biological properties of some pyrrolo[2,3-d]pyrimidine derivatives have also been mentioned. This information can be utilized to design novel diverse pyrrolopyrimidine derivatives for recent challenges in pharmaceutical and medical studies to develop the already existing drugs or discover new ones.

Development of a gas chromatography-mass spectrometric technique for the biological control of volatile industrial pollutants

Introduction. General industrial pollutants, which includes volatile industrial pollutants (VIP) allyl chloride, butyl chloride, chloroacetonitrile, pentachloroethane, hexachloroethane, trans-1,4-dichloro-2-butene, acrylonitrile, methacrylonitrile, methyl methacrylate, ethyl methacrylate, methyl acrylate, 2-nitropropane, nitrobenzene , diethyl ether, tetrahydrofuran and carbon disulfide are widely used in the domestic chemical industry, but effective methods for the quantitative determination of their biomarkers in the biological media of chemical production workers have not yet been developed. The purpose of the study is to develop a highly sensitive gas chromatographic technique for the determination of compounds of the VIP group in whole blood and urine for their biological control, and its testing using modeling of intoxication in laboratory animals. Material and methods. Experimental modeling of intoxication was carried out with subcutaneous (s/c) injection of toxicants to male chinchilla rabbits. Determination of biomarkers of toxicants was performed using a gas chromatograph with a single quadrupole mass analyzer (GC-MS) with preliminary extraction of components from the vapor phase above the sample by solid-phase microextraction. Results. A method for the determination of allyl chloride, butyl chloride, chloroacetonitrile, pentachloroethane, hexachloroethane, trans-1,4-dichloro-2-butene, acrylonitrile, methacrylonitrile, methyl methacrylate, ethyl methacrylate, methyl acrylate, 2-nitropropane, nitrobenzene, diethyl ether, tetrahydrofuran, and carbon disulfide in blood and urine was developed and metrologically certified. The achieved limits of quantification are no more than 1 ng/ml with a detection limit of 0.2 ng/ml in blood and urine. Limitations. Toxicokinetic parameters were experimentally determined on one animal species; allometric scaling was used for extrapolation to humans. Conclusion. Analysis of the results of the assessment of the expected concentrations of VIP in blood and urine shows that biological control in the working area at the level of 0.5 MPC can be carried out for carbon disulfide, diethyl ether, butyl chloride, 1,4-dichlorobutene-2 and tetrahydrofuran in the study of blood and urine; methacrylonitrile and hexachloroethane (the lower value of the determination limit) – in the study of urine only. The developed approaches to substantiate methods of biological control of harmful substances are a scientific and methodological platform for the introduction of biological MPC and ensuring the chemical safety of the Russian Federation.

AgNP Composite Silicone-Based Polymer Self-Healing Antifouling Coatings.

Biofouling poses a significant challenge to the marine industry, and silicone anti-biofouling coatings have garnered extensive attention owing to their environmental friendliness and low surface energy. However, their widespread application is hindered by their low substrate adhesion and weak static antifouling capabilities. In this study, a novel silicone polymer polydimethylsiloxane (PDMS)-based poly(urea-thiourea-imine) (PDMS-PUTI) was synthesized via stepwise reactions of aminopropyl-terminated polydimethylsiloxane (APT-PDMS) with isophorone diisocyanate (IPDI), isophthalaldehyde (IPAL), and carbon disulfide (CS2). Subsequently, a nanocomposite coating (AgNPs-x/PDMS-PUTI) was prepared by adding silver nanoparticles (AgNPs) to the polymer PDMS-PUTI. The dynamic multiple hydrogen bonds formed between urea and thiourea linkages, along with dynamic imine bonds in the polymer network, endowed the coating with outstanding self-healing properties, enabling complete scratch healing within 10 min at room temperature. Moreover, uniformly dispersed AgNPs not only reduced the surface energy of the coating but also significantly enhanced its antifouling performance. The antibacterial efficiency against common marine bacteria Pseudomonas aeruginosa (P.sp) and Staphylococcus aureus (S.sp) was reduced by 97.08% and 96.71%, respectively, whilst the diatom settlement density on the coating surface was as low as approximately 59 ± 3 diatom cells/mm2. This study presents a novel approach to developing high-performance silicone antifouling coatings.

Is Farming a Risk Occupation for Cardio-cerebrovascular Diseases? A Scoping Review on Cardio-cerebrovascular Disease Risk in Farmers.

In the Republic of Korea, cardiocerebrovascular disease (CCVD) is recognized as an occupational disease when sufficient evidence of a work-related burden exists. In 2021, approximately 26.8% of the payments from occupational disease insurance under the Industrial Accident Compensation Insurance Act were allocated to CCVDs. However, due to the specific nature of insurance policies for farmers, CCVD is not acknowledged as an occupational disease in their case. We reviewed studies on the differences in the incidence, prevalence, and mortality rates of CCVDs between farmers and the general population or other occupations and described the exposure of farmers to risk factors for CCVDs. Several studies showed that farming is a high-risk occupation for CCVDs, with the following risk factors: long working hours, night work, lack of holidays, and strenuous physical labor; physical factors (noise, cold, heat, humidity, and vibration); exposure to hazardous gases (diesel exhaust, carbon monoxide, hydrogen sulfide, carbon disulfide, nitrogen oxides, and polycyclic aromatic hydrocarbons), pesticides, and dust (particulate matter, silica, and organic dust); exposure to a hypoxic environment; and job-related stress. Social isolation and lack of accessible medical facilities also function as additional risk factors by preventing farmers from receiving early interventions. Farmers are exposed to various risk factors for CCVDs and are an occupation at risk for CCVDs. More studies are needed in the future to elucidate this relationship. This study lays the groundwork for future research to develop guidelines for approving CCVDs as occupational diseases among farmers.

A type of multifunctional cellulose nanocrystal composite silicone-based polymer coating for marine antibiofouling

Nanocomposite polymer coatings are being used as a new generation of marine antibiofouling coatings because of their toxin-free chemical composition and ease of large-scale adoption. Cellulose nanocrystal (CN) exhibits significant potential for composite reinforcement. Herein, CN was surface-modified via α,ω-bis(3-(2-hydroxyl-terminated polydimethylsiloxane (HTPDMS), resulting in dihydroxyl-terminated poly(dimethylsiloxane)-grafted CN (HP-g-CN). The amine-terminated PDMS as the foundational component was sequentially reacted with isophorone diisocyanate, isophthalaldehyde, and carbon disulfide to produce PDMS-based poly (urea-thiourea-imine) (PDMS-PUTI). Subsequently, a composite (PDMS-PUTI/HP-g-CN) was produced through physical blending. The intrinsic imine bonds and dynamic hydrogen-bonding network were responsible for the self-healing properties, which achieved a healing efficiency of up to 89.2 %. HP-g-CN was grafted with the non-leaching lubricant, HTPDMS, resulting in improved mechanical properties (1.38 MPa of ultimate strength) and adhesion strength (2.43 MPa), along with the self-cleaning and self-lubricating performance (0.700 coefficient) of the coating. Additionally, the fouling resistance to bovine serum albumin (BSA, 10.44 μg cm−2), bacteria (∼97.08 % and ∼ 98.05 % reduction for Pseudomonas sp. (P. sp.) and Shewanella sp. (S. sp.), respectively), and diatoms (∼27 cells mm−2) was further enhanced. Marine field tests conducted over 90 days revealed that the coatings were static fouling-resistant for an extended period. This study demonstrated a multifunctional, high-performance, and environmentally friendly nanocomposite polymer coating for preventing marine biofouling.

Synthesis of Cyclic Trithiocarbonates from Carbon Disulfide and Propargyl Alcohols under Mild Conditions.

A versatile method for the synthesis of cyclic trithiocarbonates has been successfully developed from readily synthesized propargyl alcohols and easily accessible carbon disulfide (CS2), where terminal and nonterminal propargyl alkynols are compatible with this methodology. The developed protocol features simple, mild, atom-economic, and transition-metal-free reaction conditions resulting in the corresponding cyclic trithiocarbonates in moderate to excellent yields.

Iron‐Promoted Redox Access to 2‐Aminobenzoxazoles from Amines, Carbon Disulfide and 2‐Nitrophenols

AbstractA method to assemble 2‐aminobenzoxazoles via iron‐catalyzed redox condensation of amines, carbon disulfide and 2‐nitrophenols is reported. The reaction features advantages of environmentally friendly iron catalyzed conditions, readily available starting materials, and excellent atom‐, step‐ and redox‐ economy compared to known protocols. Experimental investigation suggests a mechanism encompassing iron‐catalyzed reduction of the nitro group of 2‐nitrophenols by the dithiocarbamate group from amine‐CS2 adduct.

Hybrid Fibers with Subwavelength-Scale Liquid Core for Highly Sensitive Sensing and Enhanced Nonlinearity.

Interest grows in designing silicon-on-insulator slot waveguides to trap optical fields in subwavelength-scale slots and developing their optofluidic devices. However, it is worth noting that the inherent limitations of the waveguide structures may result in high optical losses and short optical paths, which challenge the device's performance in optofluidics. Incorporating the planar silicon-based slot waveguide concept into a silica-based hollow-core fiber can provide a perfect solution to realize an efficient optofluidic waveguide. Here, we propose a subwavelength-scale liquid-core hybrid fiber (LCHF), where the core is filled with carbon disulfide and surrounded by a silicon ring in a silica background. The waveguide properties and the Stimulated Raman Scattering (SRS) effect in the LCHF are investigated. The fraction of power inside the core of 56.3% allows for improved sensitivity in optical sensing, while the modal Raman gain of 23.60 m-1·W-1 is two times larger than that generated around a nanofiber with the interaction between the evanescent optical field and the surrounding Raman media benzene-methanol, which enables a significant low-threshold SRS effect. Moreover, this in-fiber structure features compactness, robustness, flexibility, ease of implementation in both trace sample consumption and reasonable liquid filling duration, as well as compatibility with optical fiber systems. The detailed analyses of the properties and utilizations of the LCHF suggest a promising in-fiber optofluidic platform, which provides a novel insight into optofluidic devices, optical sensing, nonlinear optics, etc.

Bifunctional Noble-Metal Free Ternary Chalcogenide Electrocatalysts for Water Splitting

With the ever-increasing global energy demand, the development of renewable energy technologies is crucial to fulfilling the energy requirements in a sustainable manner. Hydrogen has emerged as a promising energy carrier that can provide emission-free energy for end-use applications. Among the several pathways of hydrogen production, green hydrogen production by electrochemical water splitting using renewable energy is an emission-free, efficient energy conversion technology. Hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) occur at the cathode and anode, respectively. Water splits into hydrogen and oxygen at the thermodynamic potential of 1.23 V; however, overpotentials are observed experimentally due to the kinetic barriers, which increases the required potential for water splitting. Catalysts lower the required overpotentials, making the process more energy efficient. A significant issue with large-scale hydrogen production by water electrolysis is that the state-of-the-art catalysts for HER and OER are based on precious metals and thus are limited by their high cost and net production capacity. Thus, there is a lot of interest in developing noble-metal-free electrocatalysts based on earth-abundant materials that can efficiently lower the associated overpotentials for the two halves of the water-splitting reaction.A large number of late transition metal-based ternary complex oxides have been investigated for their catalytic performance towards water splitting, where fine-tuning of the properties using compositional engineering has been demonstrated. Binary sulfides, selenides, and phosphides have also been explored as candidates for water splitting. Recently, early transition metal-based ternary complex materials have emerged as a novel class of electronic materials with applications in infrared optics and photovoltaics. However, similar chalcogenide compositions based on late-transition metals remain underexplored.We have synthesized a series of LaMS3 (M = Mn, Fe, Co, Ni) materials by high-temperature sulfurization of corresponding ternary oxides, using carbon disulfide (CS2) as the sulfurizing agent. The LaMS3 compounds are isostructural and crystallize in the hexagonal P 63 space group. When tested for catalytic performance towards water splitting, they demonstrate good activity towards both HER and OER, with LaNiS3 (LNS) being the most active material, and a periodic activity trend is observed, where LNS > LCS >> LFS > LMS. For OER in alkaline electrolyte, LNS demonstrates an overpotential of 373 mV at 10mA/cm2 in 1.0 M KOH, and a low Tafel slope value of 48 mV/dec. The long-term stability was tested using chronopotentiometry measurements, and LNS shows excellent stability, with negligible change in overpotential over several hours. For HER testing in both acidic and alkaline electrolyte, LNS again seems to be the most active material, and a periodic activity trend in the HER activity of LaMS3 materials, similar to the OER activity trend, is observed. LNS has an overpotential of 340 mV in 0.5 M H2SO4 and 362 mV in 1.0 M KOH, indicating that LNS is catalytically active over a wide range of pH levels. LNS also shows excellent long-term stability towards HER in both acidic and alkaline electrolyte. We also compared the activity of LaMS3 materials with their ternary oxide counterparts from which they were synthesized, and the LaMS3 compounds outperform the LaMO3 compounds, demonstrating lower overpotentials and Tafel slope values for both HER and OER, with the HER overpotentials for LaMO3 materials being > 250 mV higher compared to LaMS3, for both acidic and alkaline electrolytes. The catalytic activity of the LaMS3 series towards both HER and OER, along with their excellent long-term stability, makes these materials promising candidates for bifunctional electrocatalysts for water splitting while offering a wide compositional range that allows for further optimization of their performance.

Efficient N -Trifluoromethylation of Amines with Carbon Disulfide and Silver Fluoride as Reagents

Efficient <i>N</i> -Trifluoromethylation of Amines with Carbon Disulfide and Silver Fluoride as Reagents

Discrimination of Fungicide-Contaminated Lettuces Based on Maximum Residue Limits Using Spectroscopy and Chemometrics

The fast and effective monitoring of agrochemical residues is essential for assuring food safety, since many agricultural products are sprayed with pesticides and commercialised without waiting for the pre-harvest interval. In this study, we investigated the use of spectral reflectance combined with principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) to evaluate the discrimination of fungicide-contaminated lettuces, considering three maximum residue limits (MRLs) [3.5, 5, and 7 mg carbon disulphide (CS2) kg−1]. The non-systemic Mancozeb fungicide (dithiocarbamate) was adopted in this research. Spectral reflectance (Vis/NIR) was measured by a hand-held spectrometer connected to a clip probe with an integrating sphere. The lettuce spectra were pre-treated (centring, standard normal variate, and first derivative) before data processing. Our findings suggest that PCA recognised inherent similarities in the fungicide-contaminated lettuce spectra, categorising them into two distinct groups. The PLS-DA models for all MRLs resulted in high accuracy levels, with correct discriminations ranging from 94.5 to 100% for the external validation dataset. Overall, our study demonstrates that spectroscopy combined with discriminating methods is a promising tool for non-destructive and fast discrimination of fungicide-contaminated lettuces. This methodology can be used in industrial food processing, enabling large-scale individual analysis and real-time decision making.