Variations and driving factors for concentrations and carbon isotopes of dissolved CO in lake water across different Chinese lakes.

Carbon dioxide (CO) stands as the primary driver of Earth's greenhouse effect, and it's suggested that the global contribution of CO emissions from lakes cannot be ignored. Despite the numerous estimations of CO fluxes from lakes, limited focus has been directed towards the carbon isotopes (δC) of dissolved CO in lake water. Particularly, the potential use of δC values in tracing the CO concentrations in lake water remains as an understudied area, warranting further exploration and investigation.

Salinity decreases methane concentrations in Chinese lakes.

Lakes are important sources of methane (CH), and understanding the influence of environmental factors on CH concentration in lake water is crucial for accurately assessing CH emission from lakes. In this study, we investigated CH concentration in two connected Tibetan Plateau lakes, Lake Keluke (an open freshwater lake) and Lake Tuosu (a closed saline lake), through in-situ continuous measurements taken in different months from 2021 to 2023. The results show substantial spatial and seasonal variations in CH concentrations in the two lakes, while the CH concentrations in Lake Keluke are consistently higher than those in Lake Tuosu for each month.

Multi-functional terahertz metasurface for a vortex beam, multi-channel focusing, polarization conversion, and broadband absorption based on vanadium dioxide.

Although terahertz metasurface devices have been widely studied, thus far, metasurfaces can rarely manipulate both circularly and linearly polarized incident waves. In this paper, taking advantage of the phase transition characteristics of vanadium dioxide ( ), a multi-functional terahertz metasurface for a vortex beam, multi-channel focusing, polarization conversion, and broadband absorption is proposed. When is in the insulating state, a vortex beam is generated at 1.

High-precision zinc isotopic characterization of twenty soil reference materials from China determined by MC-ICP-MS.

Zinc isotopic ratios serve as powerful tools for tracing biochemical cycling of metals at Earth's surface, including the distribution, transportation, and enrichment of zinc (Zn) in soil. To conduct such studies and enable inter-laboratory comparisons, high-precision Zn isotopic measurements require the use of soil reference materials (RMs). However, there have been limited reports on the high-precision Zn isotope ratios of soil RMs thus far.

Alpine permafrost could account for a quarter of thawed carbon based on Plio-Pleistocene paleoclimate analogue.

Estimates of the permafrost-climate feedback vary in magnitude and sign, partly because permafrost carbon stability in warmer-than-present conditions is not well constrained. Here we use a Plio-Pleistocene lacustrine reconstruction of mean annual air temperature (MAAT) from the Tibetan Plateau, the largest alpine permafrost region on the Earth, to constrain past and future changes in permafrost carbon storage. Clumped isotope-temperatures (Δ-T) indicate warmer MAAT (~1.

The differences in the nitrogen isotope composition between a maize hybrid and its parents.

Understanding of nitrogen stable isotope variation in maize hybrids might help obtaining information on nitrogen absorption and distribution in different maize hybrids. In this study, we examined the nitrogen isotopic composition of different parts of maize hybrids under a laboratory culture experiment. The results showed that the δ15N values of different parts of the maize hybrid and its parents were ordered as follows: δ15Nstem>δ15Nleaf>δ15Nroot.

Quantifying biodegradable organic matter in polluted water on the basis of coulombic yield.

Biodegradable organic matter (BOM) in polluted water plays a key role in various biological purification technologies. The five-day biochemical oxygen demand (BOD) index is often used to determine the amount of BOM. However, standard BOD assays, centering on dissolved oxygen detection, have long testing times and often show severe deviation (error ≥ 15%).

Self-Assembled Modified Soy Protein/Dextran Nanogel Induced by Ultrasonication as a Delivery Vehicle for Riboflavin.

A simple and green approach was developed to produce a novel nanogel via self-assembly of modified soy protein and dextran, to efficiently deliver riboflavin. First, modified soy protein was prepared by heating denaturation at 60 °C for 30 min or Alcalase hydrolysis for 40 min. Second, modified soy protein was mixed with dextran and ultrasonicated for 70 min so as to assemble nanogels.

[Study on the content and carbon isotopic composition of water dissolved inorganic carbon from rivers around Xi'an City].

In this study, the content and isotopic compositions of water dissolved inorganic carbon (DIC) from four typical rivers (Chanhe, Bahe, Laohe and Heihe) around Xi'an City were studied to trace the possible sources of DIC. The results of this study showed that the content of DIC in the four rivers varied from 0.34 to 5.

Kinetics of CH3S(-) reaction with in situ ferrate(VI) in aqueous alkaline solution.

This study introduced a new treatment process named "in situ ferrate(VI) oxidation (IFO)" in which odorous compounds such as CH3S(-) can be quickly degraded by in situ freshly generated ferrate(VI) through electrolysis in aqueous alkaline solution. Two kinetic models to describe the in situ ferrate(VI) generation and its reaction with CH3S(-) were established mathematically by considering three main reaction mechanisms of ferrate(VI) electrochemical generation, ferrate(VI) self-decomposition and CH3S(-) degradation in aqueous strong alkaline solution. The effects of three key factors: (i) NaOH concentration, (ii) applied current density, and (iii) initial CH3S(-) concentration on the performance of the IFO process were investigated by conducting three sets of experiments and the kinetic models were validated by fitting the experimental data.

Interplay between the Westerlies and Asian monsoon recorded in Lake Qinghai sediments since 32 ka.

Two atmospheric circulation systems, the mid-latitude Westerlies and the Asian summer monsoon (ASM), play key roles in northern-hemisphere climatic changes. However, the variability of the Westerlies in Asia and their relationship to the ASM remain unclear. Here, we present the longest and highest-resolution drill core from Lake Qinghai on the northeastern Tibetan Plateau (TP), which uniquely records the variability of both the Westerlies and the ASM since 32 ka, reflecting the interplay of these two systems.

Mesoporous zinc ferrite: synthesis, characterization, and photocatalytic activity with H2O2/visible light.

Mesoporous ZnFe(2)O(4) (meso-ZnFe(2)O(4)) was synthesized by a hydrothermal process in which cetyltrimethylammonium bromide (CTAB) participates in the reaction to produce nanocrystals. Synthesized ZnFe(2)O(4) was characterized by energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area, scanning electronic microscopy (SEM), transmission electron microscopy (TEM), and diffuse reflectance spectra (DRS). The meso-ZnFe(2)O(4) was resulted from the agglomeration of nanoparticles with size of 5-10nm.

Effect of preservation on the δ¹³C value of dissolved inorganic carbon in different types of water samples.

Recent studies have shown that the stable carbon isotope compositions of dissolved inorganic carbon (δ(13)C(DIC)) of water samples preserved with HgCl(2) and CuSO(4) vary. Furthermore, mercury and cuprum compounds are toxic to the human or biological system and require proper waste disposal. To test the effect of preservation on the δ(13)C value of DIC in different types of water samples, a set of water samples with different DIC concentrations was preserved using different methods, including preserving with inhibitors (CuSO(4) or HgCl(2)), preserving under frozen conditions, filtering through a 0.

[Study on the inhibitory effect of RNA interference on replication of dengue virus].

To investigate the inhibitory effect of RNA interference (RNAi) on dengue virus I (DENV-1) replication. Small interfering RNA (siRNA) against the PreM gene of dengue virus was synthesized and transfected into C6/36 cells with liposome, which was then attacked by DENV-1 virus. The antiviral effect of siRNA was evaluated by cytopathic effect (CPE), the cell survival rate measured by MTT, and virus RNA quantified by real-time RT-PCR.

Inhibitory effect of small interfering RNA on dengue virus replication in mosquito cells.

Background: Dengue viruses (DENs) are the wildest transmitted mosquito-borne pathogens throughout tropical and sub-tropical regions worldwide. Infection with DENs can cause severe flu-like illness and potentially fatal hemorrhagic fever. Although RNA interference triggered by long-length dsRNA was considered a potent antiviral pathway in the mosquito, only limited studies of the value of small interfering RNA (siRNA) have been conducted.

Comparison of the degradations of diphenamid by homogeneous photolysis and heterogeneous photocatalysis in aqueous solution.

In this work, the homogeneous and heterogeneous degradations of diphenamid (DPA) in aqueous solution were conducted by direct photolysis with UVC (254nm) and by photocatalysis with TiO(2)/UVA (350nm), and the experimental results were compared. It was found that the homogeneous photolysis by UVC irradiation alone was quite efficient to degrade DPA up to 100% after 360min, but was very inefficient to mineralize its intermediates in terms of dissolved organic carbon reduction of only 8%. In contrast, the heterogeneous photocatalysis with TiO(2)/UVA showed relatively a lower degree of DPA degradation (51%), but a higher degree of its mineralization (11%) after 360min.

Effects of key reaction parameters on the reductive dechlorination of chloroform with Pd/Fe0 bimetal in aqueous solution.

In this study, bimetallic Pd/Fe(0) particles were synthesized and employed to reduce chloroform in aqueous solution. The investigation emphasized on the effects of some key reaction parameters including Pd/Fe(0) dosage, pH, oxidation-reduction potential (ORP) and presence of anions on the reductive dechlorination reaction. The experimental results showed that high Pd/Fe(0) dosage, low initial pH and low ORP benefited the reductive dechlorination of chloroform.

Bio-electro-Fenton process driven by microbial fuel cell for wastewater treatment.

In this study, we proposed a new concept of utilizing the biological electrons produced from a microbial fuel cell (MFC) to power an E-Fenton process to treat wastewater at neutral pH as a bioelectro-Fenton (Bio-E-Fenton) process. This process can be achieved in a dual-chamber MFC from which electrons were generated via the catalyzation of Shewanella decolorationis S12 in its anaerobic anode chamber and transferred to its aerated cathode chamber equipped with a carbon nanotube (CNT)/gamma-FeOOH composite cathode. In the cathode chamber, the Fenton's reagents including hydrogen peroxide (H(2)O(2)) and ferrous irons (Fe(2+)) were in situ generated.

Heterogeneous photodegradation of pentachlorophenol and iron cycling with goethite, hematite and oxalate under UVA illumination.

Heterogeneous photodegradation of pentachlorophenol (PCP) in the goethite (alpha-FeOOH) and hematite (alpha-Fe(2)O(3)) systems with oxalate under UVA illumination was investigated. The PCP degradation, dechlorination and detoxification, in terms of Microtox acute toxicity, were all achieved to the higher efficiency in the hematite suspension than in the goethite suspension. The optimal initial concentration of oxalic acid (C(ox)(0)) for the PCP degradation with goethite and hematite under the experimental conditions was found to be 1.

Elimination of sludge odor by oxidizing sulfur-containing compounds with ferrate(VI).

Sulfur-containing compounds are one kind of odorant found in sewage treatment works, composting plants, refuse storage and transfer, landfill sites, and associated with various industries. In the present research, the reaction kinetics of ferrate(VI) (Fe(VI)O4(-), Fe(VI)) with 2-mercaptobenzothiazole (MBT), thiosemicarbazide (NH2NHC(S)NH2, TSC), and thiourea dioxide (NH2C(SO2)NH2, TUDO) were studied under alkaline conditions. Stoichiometryof Fe(VI) oxidation with hydrogen sulfide (H2S), TSC, and methyl mercaptan (CH3SH) were determined at neutral and alkaline pH (7.

Microbial fuel cell with an azo-dye-feeding cathode.

Microbial fuel cells (MFCs) were constructed using azo dyes as the cathode oxidants to accept the electrons produced from the respiration of Klebsiella pneumoniae strain L17 in the anode. Experimental results showed that a methyl orange (MO)-feeding MFC produced a comparable performance against that of an air-based one at pH 3.0 and that azo dyes including MO, Orange I, and Orange II could be successfully degraded in such cathodes.

Electrochemical evidences for promoted interfacial reactions: the role of Fe(II) adsorbed onto gamma-Al2O3 and TiO2 in reductive transformation of 2-nitrophenol.

This study was aimed at elucidating the role of adsorbed Fe(II) on minerals in the reductive transformation of 2-nitrophenol (2-NP) by using electrochemical methods. The studies of Fe(ll) adsorption and 2-NP reduction kinetics showed that the identity of minerals such as gamma-Al2O3 and TiO and the solution pH were crucial factors to determine the Fe(ll) adsorption behavior and to influence the rate constant (k) of 2-NP reduction. Furthermore, two electrochemical methods, cyclic voltammetry (CV) and electrochemical impedance spectrometry (EIS), were applied to characterize the Fe(II) reactivity with both the mineral-coated and mineral-free electrodes.

Ferrate(VI) enhanced photocatalytic oxidation of pollutants in aqueous TiO2 suspensions.

Background, Aim And Scope: Photocatalytic oxidation using UV irradiation of TiO(2) has been studied extensively and has many potential industrial applications, including the degradation of recalcitrant contaminants in water and wastewater treatment. A limiting factor in the oxidation process is the recombination of conduction band electrons (e(-)(cb)) with electron holes (h(vb)(+)) on the irradiated TiO(2) surface; thus, in aqueous conditions, the presence of an effective electron scavenger will be beneficial to the efficiency of the oxidation process. Ferrate (FeO(4)(2-)) has received much recent attention as a water treatment chemical since it behaves simultaneously as an oxidant and coagulant.

A new concept of desulfurization: the electrochemically driven and green conversion of SO2 to NaHSO4 in aqueous solution.

A new concept of desulfurization was developed by designing a series of electrochemical reactions to drive an SO2 absorption-and-conversion process in aqueous solution, hence the SO2 in gas was eventually converted to a valuable chemical of NaHSO4. A model experiment of chemically substantiating this concept includes two steps: (I) absorption of SO2 gas by aqueous solution and oxidation of the absorbed SO2 to SO4(2-) by air and (II) transformation of the SO4(2-) to NaHSO4. The experiment demonstrated that in Step I, the cathodic reduction of 02 from ambient air scavenged the H+ released due to the SO2 absorption and its further oxidation, which thereby were accelerated.

Heterogeneous photodegradation of pentachlorophenol with maghemite and oxalate under UV illumination.

The degradation of pentachlorophenol (PCP) in a heterogeneous system with maghemite (gamma-Fe2O3) and oxalate under UV illumination was investigated in this study. The results of adsorption experiments demonstrated competitive adsorption between PCP and oxalic acid on the surface of gamma-Fe2O3. The results of photodegradation experiments showed that the rate of PCP degradation strongly relied on the oxalic acid concentration and that an optimal tested initial concentration of oxalic acid (Cox(0)) of 0.