Dissolved carbon in biochar: Exploring its chemistry, iron complexing capability, toxicity in natural redox environment.

Dissolved black carbon (DBC) plays a crucial role in the migration and bioavailability of iron in water. However, the properties of DBC releasing under diverse pyrolysis conditions and dissolving processes have not been systematically studied. Here, the compositions of DBC released from biochar through redox processes dominated by bacteria and light were thoroughly studied. It was found that the DBC released from straw biochar possess more oxygen-containing functional groups and aromatic substances. The content of phenolic and carboxylic groups in DBC was increased under influence of microorganisms and light, respectively. The concentration of phenolic hydroxyl groups increased from 10.0∼57.5 mmol/gC to 6.6 ∼65.2 mmol/gC, and the concentration of carboxyl groups increased from 49.7∼97.5 mmol/gC to 62.1 ∼113.3 mmol/gC. Then the impacts of DBC on pyrite dissolution and microalgae growth were also investigated. The complexing Fe3+ was proved to play a predominant role in the dissolution of ferrous mineral in DBC solution. Due to complexing between iron ion and DBC, the amount of dissolved Fe in aquatic water may rise as a result of elevated number of aromatic components with oxygen containing groups and low molecular weight generated under light conditions. Fe-DBC complexations in solution significantly promoted microalga growth, which might be attributed to the stimulating effect of dissolved Fe on the chlorophyll synthesis. The results of study will deepen our understanding of the behavior and ultimate destiny of DBC released into an iron-rich environment under redox conditions.

Degradation of gaseous hydrocarbons in aerated stirred bioreactors inoculated with Rhodococcus erythropolis: Effect of the carbon source and SIFT-MS method development.

The study of microbial hydrocarbons removal is of great importance for the development of future bioremediation strategies. In this study, we evaluated the removal of a gaseous mixture containing toluene, m-xylene, ethylbenzene, cyclohexane, butane, pentane, hexane and heptane in aerated stirred bioreactors inoculated with Rhodococcus erythropolis and operated under non-sterile conditions. For the real-time measurement of hydrocarbons, a novel systematic approach was implemented using Selected-Ion Flow Tube Mass Spectrometry (SIFT-MS). The effect of the carbon source (∼9.5 ppmv) on (i) the bioreactors' performance (BR1: dosed with only cyclohexane as a single hydrocarbon versus BR2: dosed with a mixture of the 8 hydrocarbons) and (ii) the evolution of microbial communities over time were investigated. The results showed that cyclohexane reached a maximum removal efficiency (RE) of 53% ± 4% in BR1. In BR2, almost complete removal of toluene, m-xylene and ethylbenzene, being the most water-soluble and easy-to-degrade carbon sources, was observed. REs below 32% were obtained for the remaining compounds. By exposing the microbial consortium to only the five most recalcitrant hydrocarbons, REs between 45% ± 5% and 98% ± 1% were reached. In addition, we observed that airborne microorganisms populated the bioreactors and that the type of carbon source influenced the microbial communities developed. The abundance of species belonging to the genus Rhodococcus was below 10% in all bioreactors at the end of the experiments. This work provides fundamental insights to understand the complex behavior of gaseous hydrocarbon mixtures in bioreactors, along with a systematic approach for the development of SIFT-MS methods.

Impact of residual antibiotics on microbial decomposition of livestock manures in Eutric Regosol: Implications for sustainable nutrient recycling and soil carbon sequestration.

The land application of livestock manure has been widely acknowledged as a beneficial approach for nutrient recycling and environmental protection. However, the impact of residual antibiotics, a common contaminant of manure, on the degradation of organic compounds and nutrient release in Eutric Regosol is not well understood. Here, we studied, how oxytetracycline (OTC) and ciprofloxacin (CIP) affect the decomposition, microbial community structure, extracellular enzyme activities and nutrient release from cattle and pig manure using litterbag incubation experiments. Results showed that OTC and CIP greatly inhibited livestock manure decomposition, causing a decreased rate of carbon (28%-87%), nitrogen (15%-44%) and phosphorus (26%-43%) release. The relative abundance of gram-negative (G-) bacteria was reduced by 4.0%-13% while fungi increased by 7.0%-71% during a 28-day incubation period. Co-occurrence network analysis showed that antibiotic exposure disrupted microbial interactions, particularly among G- bacteria, G+ bacteria, and actinomycetes. These changes in microbial community structure and function resulted in decreased activity of urease, ß-1,4-N-acetyl-glucosaminidase, alkaline protease, chitinase, and catalase, causing reduced decomposition and nutrient release in cattle and pig manures. These findings advance our understanding of decomposition and nutrient recycling from manure-contaminated antibiotics, which will help facilitate sustainable agricultural production and soil carbon sequestration.

Oleaginous fungi: a promising source of biofuels and nutraceuticals with enhanced lipid production strategies.

Oleaginous fungi have attracted a great deal of interest for their potency to accumulate high amounts of lipids (more than 20% of biomass dry weight) and polyunsaturated fatty acids (PUFAs), which have a variety of industrial and biological applications. Lipids of plant and animal origin are related to some restrictions and thus lead to attention towards oleaginous microorganisms as reliable substitute resources. Lipids are traditionally biosynthesized intra-cellularly and involved in the building structure of a variety of cellular compartments. In oleaginous fungi, under certain conditions of elevated carbon ratio and decreased nitrogen in the growth medium, a change in metabolic pathway occurred by switching the whole central carbon metabolism to fatty acid anabolism, which subsequently resulted in high lipid accumulation. The present review illustrates the bio-lipid structure, fatty acid classes and biosynthesis within oleaginous fungi with certain key enzymes, and the advantages of oleaginous fungi over other lipid bio-sources. Qualitative and quantitative techniques for detecting the lipid accumulation capability of oleaginous microbes including visual, and analytical (convenient and non-convenient) were debated. Factors affecting lipid production, and different approaches followed to enhance the lipid content in oleaginous yeasts and fungi, including optimization, utilization of cost-effective wastes, co-culturing, as well as metabolic and genetic engineering, were discussed. A better understanding of the oleaginous fungi regarding screening, detection, and maximization of lipid content using different strategies could help to discover new potent oleaginous isolates, exploit and recycle low-cost wastes, and improve the efficiency of bio-lipids cumulation with biotechnological significance.

Does digital inclusive finance promote carbon emission reduction of enterprises.

Can the information technology revolution lead to carbon emission reduction for firms? This study extends the limited evidence in the literature and investigate the role and mechanism of digital inclusive finance on enterprises' carbon emissions using panel data of 247 prefectural-level cities and 6019 industrial enterprises in China. Our findings indicate that digital inclusive finance can promote enterprise carbon emission reduction, and this effect remains significant after the instrumental variable estimation test. The effect has regional heterogeneity and the development of digital inclusive finance in the area east of Hu Huanyong line has a significant impact on reducing enterprise carbon emission. The role of digital inclusive finance is heterogeneous in enterprise ownership, with a remarkable effect in non-state-owned enterprises. Sub-dimension analysis indicates that the breadth of coverage, depth of use, and degree of digitalization of digital inclusive finance have differential effects on reducing enterprise carbon emissions. The stepwise regression method shows that the impact of digital inclusive finance on enterprise carbon emissions can be passed through effect of technological progress, environmental protection investment and financing constrain. This study has significant reference value for evaluating the impact of financial inclusion and policy implications in formulating differentiated strategies for achieving carbon emission reduction efficiency in enterprises.

Therapeutic Potential of Nitrogen-Doped Rutin-Bound Glucose Carbon Dots for Alzheimer's Disease.

The blood-brain barrier (BBB) prevents the use of many drugs for the treatment of neurological disorders. Recently, nitrogen-doped carbon dots (NCDs) have emerged as promising nanocarriers to cross BBB. The primary focus of our study was to evaluate the effectiveness of NCDs for the symptomatic treatment of Alzheimer's disease (AD). In this study, we developed and characterized NCDs bound to rutin, a flavonoid with known benefits for AD. Despite its benefits, the transportation of rutin via NCDs for AD therapy has not been explored previously. We characterized the particles using FTIR and UV-visible spectroscopy followed by atomic force microscopy. Once the design was optimized and validated, we performed in vivo testing via a hemolytic assay to optimize the dosage. Preliminary in vitro testing was performed in AlCl3-induced rat models of AD whereby a single dose of 10 mg/kg NCDs-rutin was administered intraperitoneally. Interestingly, this single dose of 10 mg/kg NCDs-rutin produced the same behavioral effects as 50 mg/kg rutin administered intraperitoneally for 1 month. Similarly, histological and biomarker profiles (SOD2 and TLR4) also presented significant protective effects of NCDs-rutin against neuronal loss, inflammation, and oxidative stress. Hence, NCDs-rutin are a promising approach for the treatment of neurological diseases.

Interplay between photosynthetic electron flux and organic carbon sinks in sucrose-excreting Synechocystis sp. PCC 6803 revealed by omics approaches.

BACKGROUND: Advancing the engineering of photosynthesis-based prokaryotic cell factories is important for sustainable chemical production and requires a deep understanding of the interplay between bioenergetic and metabolic pathways. Rearrangements in photosynthetic electron flow to increase the efficient use of the light energy for carbon fixation must be balanced with a strong carbon sink to avoid photoinhibition. In the cyanobacterium Synechocystis sp. PCC 6803, the flavodiiron protein Flv3 functions as an alternative electron acceptor of photosystem I and represents an interesting engineering target for reorganizing electron flow in attempts to enhance photosynthetic CO2 fixation and increase production yield. RESULTS: We have shown that inactivation of Flv3 in engineered sucrose-excreting Synechocystis (S02:Δflv3) induces a transition from photoautotrophic sucrose production to mixotrophic growth sustained by sucrose re-uptake and the formation of intracellular carbon sinks such as glycogen and polyhydroxybutyrate. The growth of S02:Δflv3 exceeds that of the sucrose-producing strain (S02) and demonstrates unforeseen proteomic and metabolomic changes over the course of the nine-day cultivation. In the absence of Flv3, a down-regulation of proteins related to photosynthetic light reactions and CO2 assimilation occurred concomitantly with up-regulation of those related to glycolytic pathways, before any differences in sucrose production between S02 and S02:Δflv3 strains were observed. Over time, increased sucrose degradation in S02:Δflv3 led to the upregulation of respiratory pathway components, such as the plastoquinone reductase complexes NDH-11 and NDH-2 and the terminal respiratory oxidases Cyd and Cox, which transfer electrons to O2. While glycolytic metabolism is significantly up-regulated in S02:Δflv3 to provide energy for the cell, the accumulation of intracellular storage compounds and the increase in respiration serve as indirect sinks for photosynthetic electrons. CONCLUSIONS: Our results show that the presence of strong carbon sink in the engineered sucrose-producing Synechocystis S02 strain, operating under high light, high CO2 and salt stress, cannot compensate for the lack of Flv3 by directly balancing the light transducing source and carbon fixing sink reactions. Instead, the cells immediately sense the imbalance, leading to extensive reprogramming of cellular bioenergetic, metabolic and ion transport pathways that favor mixotrophic growth rather than enhancing photoautotrophic sucrose production.

Application of slow-controlled release fertilizer coordinates the carbon flow in carbon-nitrogen metabolism to effect rice quality.

Slow-controlled release fertilizers are experiencing a popularity in rice cultivation due to their effectiveness in yield and quality with low environmental costs. However, the underlying mechanism by which these fertilizers regulate grain quality remains inadequately understood. This study investigated the effects of five fertilizer management practices on rice yield and quality in a two-year field experiment: CK, conventional fertilization, and four applications of slow-controlled release fertilizer (UF, urea formaldehyde; SCU, sulfur-coated urea; PCU, polymer-coated urea; BBF, controlled-release bulk blending fertilizer). In 2020 and 2021, the yields of UF and SCU groups showed significant decreases when compared to conventional fertilization, accompanied by a decline in nutritional quality. Additionally, PCU group exhibited poorer cooking and eating qualities. However, BBF group achieved increases in both yield (10.8 t hm-2 and 11.0 t hm-2) and grain quality reaching the level of CK group. The adequate nitrogen supply in PCU group during the grain-filling stage led to a greater capacity for the accumulation of proteins and amino acids in the PCU group compared to starch accumulation. Intriguingly, BBF group showed better carbon-nitrogen metabolism than that of PCU group. The optimal nitrogen supply present in BBF group suitable boosted the synthesis of amino acids involved in the glycolysis/ tricarboxylic acid cycle, thereby effectively coordinating carbon-nitrogen metabolism. The application of the new slow-controlled release fertilizer, BBF, is advantageous in regulating the carbon flow in the carbon-nitrogen metabolism to enhance rice quality.

Towards a low-carbon and beautiful world: assessing the impact of digital technology on the common benefits of pollution reduction and carbon reduction.

When ecology thrives, civilization thrives, and when ecology declines, civilization declines. Based on panel data from 30 provinces in China from 2000 to 2021, this study used marginal abatement costs to estimate the co-benefits of pollution reduction and carbon reduction. Two-way fixed effect and two-stage intermediary effect models were used to evaluate the impact of digital technology on co-benefits and its indirect channels. The results indicated that China's total carbon emissions maintained a steady growth trend, while air pollution showed a fluctuating declining trend. Reaching peak carbon neutrality calls for more innovative solutions. Under joint emission reduction efforts, the study revealed marginal abatement cost savings of 535.8 million yuan/million tons and 6216.5 million yuan/µg/m3 for carbon reduction and pollution reduction, respectively. Most importantly, the study confirmed that joint emission reduction programs can reduce environmental governance costs more than individual emission reductions can, and the co-benefits increased from 37.983 to 44.757. The co-benefits generally showed a trend of fluctuation and increases and had the characteristics of phased transformation. Intragroup differences and cross-overlapping between regions made regional differences in co-benefits obvious. The subversive, permeable, and integrated features of digital technology have resulted in the all-around transformation of the economy and society, and the new technology-economy paradigm has significantly improved co-benefits. The conclusion remains valid after robustness testing and controlling for endogeneity problems. The results of the mechanism analysis suggest that digital technology can indirectly improve synergies through the intermediary channels of fostering green technology innovation, reducing energy consumption intensity and improving the energy structure.

Inhibition of microbially mediated total organic carbon decomposition in different types of cadmium contaminated soils with wheat straw addition.

Wheat straw returning is a common agronomic measure in the farmland. Understanding organic carbon transformation is of great significance for carbon budget under the premise of widespread distribution of cadmium (Cd) contaminated soils. An incubation experiment was conducted to assess the influence of Cd contamination on the decomposition and accumulation of total organic carbon (TOC) as well as the composition and abundance of bacterial communities in eight soil types with wheat straw addition. The results showed that inhibition of Cd contamination on microbially mediated organic carbon decomposition was affected by soil types. The lower cumulative C mineralization and higher TOC content could be observed in the acidic soils relative to that in the alkaline soils. The content of Cd in soil exhibits different effects on the inhibition in decomposition of TOC. The high dosage level of Cd had stronger inhibitory impact due to its high toxicity. The decomposition of TOC was restricted by a reduction in soil bacterial abundance and weakening of bacterial activities. Redundancy analysis (RDA) indicated that Proteobacteria and Gemmatimonadetes were abundant in alkaline Cd-contaminated soils with wheat straw addition, while Bacteroidetes dominated cumulative C mineralization in acidic Cd-contamination soils. Moreover, the abundance of predicted functional bacteria indicated that high-dose Cd-contamination and acid environment all inhibited the decomposition of TOC. The present study suggested that pH played an important role on carbon dynamics in the Cd-contaminated soils with wheat straw addition.

Transcriptomic response of prostate cancer cells to carbon ion and photon irradiation with focus on androgen receptor and TP53 signaling.

BACKGROUND: Radiotherapy is essential in the treatment of prostate cancer. An alternative to conventional photon radiotherapy is the application of carbon ions, which provide a superior intratumoral dose distribution and less induced damage to adjacent healthy tissue. A common characteristic of prostate cancer cells is their dependence on androgens which is exploited therapeutically by androgen deprivation therapy in the advanced prostate cancer stage. Here, we aimed to analyze the transcriptomic response of prostate cancer cells to irradiation by photons in comparison to carbon ions, focusing on DNA damage, DNA repair and androgen receptor signaling. METHODS: Prostate cancer cell lines LNCaP (functional TP53 and androgen receptor signaling) and DU145 (dysfunctional TP53 and androgen receptor signaling) were irradiated by photons or carbon ions and the subsequent DNA damage was assessed by immuno-cytofluorescence. Furthermore, the cells were treated with an androgen-receptor agonist. The effects of irradiation and androgen treatment on the gene regulation and the transcriptome were investigated by RT-qPCR and RNA sequencing, followed by bioinformatic analysis. RESULTS: Following photon or carbon ion irradiation, both LNCaP and DU145 cells showed a dose-dependent amount of visible DNA damage that decreased over time, indicating occurring DNA repair. In terms of gene regulation, mRNAs involved in the TP53-dependent DNA damage response were significantly upregulated by photons and carbon ions in LNCaP but not in DU145 cells, which generally showed low levels of gene regulation after irradiation. Both LNCaP and DU145 cells responded to photons and carbon ions by downregulation of genes involved in DNA repair and cell cycle, partially resembling the transcriptome response to the applied androgen receptor agonist. Neither photons nor carbon ions significantly affected canonical androgen receptor-dependent gene regulation. Furthermore, certain genes that were specifically regulated by either photon or carbon ion irradiation were identified. CONCLUSION: Photon and carbon ion irradiation showed a significant congruence in terms of induced signaling pathways and transcriptomic responses. These responses were strongly impacted by the TP53 status. Nevertheless, irradiation mode-dependent distinct gene regulations with undefined implication for radiotherapy outcome were revealed. Androgen receptor signaling and irradiations shared regulation of certain genes with respect to DNA-repair and cell-cycle.

Biochemical properties of novel Carbon nanodot-stabilized silver nanoparticles enriched calcium hydroxide endodontic sealer.

Calcium Hydroxide-based endodontic sealer loaded with antimicrobial agents have been commonly employed in conventional root canal treatment. These sealers are not effective against E. faecalis due to the persistent nature of this bacterium and its ability to evade the antibacterial action of calcium hydroxide. Therefore, endodontic sealer containing Carbon nanodots stabilized silver nanoparticles (CD-AgNPs) was proposed to combat E. faecalis. The therapeutic effect of CD-AgNPs was investigated and a new cytocompatible Calcium Hydroxide-based endodontic sealer enriched with CD-AgNPs was synthesized that exhibited a steady release of Ag+ ions and lower water solubility at 24 hours, and enhanced antibacterial potential against E. faecalis. CD-AgNPs was synthesized and characterized morphologically and compositionally by Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy (FTIR), and UV-Vis Spectroscopy, followed by optimization via minimum inhibitory concentration (MIC) determination against E. faecalis by broth microdilution technique and Cytotoxicity analysis against NIH3T3 cell lines via Alamar Blue assay. Calcium hydroxide in distilled water was taken as control (C), Calcium hydroxide with to CD-AgNPs (5mg/ml and 10mg/ml) yielded novel endodontic sealers (E1 and E2). Morphological and chemical analysis of the novel sealers were done by SEM and FTIR; followed by in vitro assessment for antibacterial potential against E. faecalis via agar disc diffusion method, release of Ag+ ions for 21 days by Atomic Absorption Spectrophotometry and water solubility by weight change for 21 days. CD-AgNPs were 15-20 nm spherical-shaped particles in uniformly distributed clusters and revealed presence of constituent elements in nano-assembly. FTIR spectra revealed absorption peaks that correspond to various functional groups. UV-Vis absorption spectra showed prominent peaks that correspond to Carbon nanodots and Silver nanoparticles. CD-AgNPs exhibited MIC value of 5mg/ml and cytocompatibility of 84.47% with NIH3T3 cell lines. Novel endodontic sealer cut-discs revealed irregular, hexagonal particles (100-120 nm) with aggregation and rough structure with the presence of constituent elements. FTIR spectra of novel endodontic sealers revealed absorption peaks that correspond to various functional groups. Novel endodontic sealers exhibited enhanced antibacterial potential where E-2 showed greatest inhibition zone against E. faecalis (6.3±2 mm), a steady but highest release of Ag+ ions was exhibited by E-1 (0.043±0.0001 mg/mL) and showed water solubility of <3% at 24 hours where E-2 showed minimal weight loss at all time intervals. Novel endodontic sealers were cytocompatible and showed enhanced antibacterial potential against E. faecalis, however, E2 outperformed in this study in all aspects.

Carbon-phosphorus cycle models overestimate CO2 enrichment response in a mature Eucalyptus forest.

The importance of phosphorus (P) in regulating ecosystem responses to climate change has fostered P-cycle implementation in land surface models, but their CO2 effects predictions have not been evaluated against measurements. Here, we perform a data-driven model evaluation where simulations of eight widely used P-enabled models were confronted with observations from a long-term free-air CO2 enrichment experiment in a mature, P-limited Eucalyptus forest. We show that most models predicted the correct sign and magnitude of the CO2 effect on ecosystem carbon (C) sequestration, but they generally overestimated the effects on plant C uptake and growth. We identify leaf-to-canopy scaling of photosynthesis, plant tissue stoichiometry, plant belowground C allocation, and the subsequent consequences for plant-microbial interaction as key areas in which models of ecosystem C-P interaction can be improved. Together, this data-model intercomparison reveals data-driven insights into the performance and functionality of P-enabled models and adds to the existing evidence that the global CO2-driven carbon sink is overestimated by models.

Dual Functional Magnetic Nanoparticles Conjugated with Carbon Quantum Dots for Hyperthermia and Photodynamic Therapy for Cancer.

The global incidence of cancer continues to rise, posing a significant public health concern. Although numerous cancer therapies exist, each has limitations and complications. The present study explores alternative cancer treatment approaches, combining hyperthermia and photodynamic therapy (PDT). Magnetic nanoparticles (MNPs) and amine-functionalized carbon quantum dots (A-CQDs) were synthesized separately and then covalently conjugated to form a single nanosystem for combinational therapy (M-CQDs). The successful conjugation was confirmed using zeta potential, Fourier transform infrared spectroscopy (FT-IR), and UV-visible spectroscopy. Morphological examination in transmission electron microscopy (TEM) further verified the conjugation of CQDs with MNPs. Energy dispersive X-ray spectroscopy (EDX) revealed that M-CQDs contain approximately 12 weight percentages of carbon. Hyperthermia studies showed that both MNP and M-CQDs maintain a constant therapeutic temperature at lower frequencies (260.84 kHz) with high specific absorption rates (SAR) of 118.11 and 95.04 W/g, respectively. In vitro studies demonstrated that MNPs, A-CQDs, and M-CQDs are non-toxic, and combinational therapy (PDT + hyperthermia) resulted in significantly lower cell viability (~4%) compared to individual therapies. Similar results were obtained with Hoechst and propidium iodide (PI) staining assays. Hence, the combination therapy of PDT and hyperthermia shows promise as a potential alternative to conventional therapies, and it could be further explored in combination with existing conventional treatments.

Four decades of data indicate that planted mangroves stored up to 75% of the carbon stocks found in intact mature stands.

Mangroves' ability to store carbon (C) has long been recognized, but little is known about whether planted mangroves can store C as efficiently as naturally established (i.e., intact) stands and in which time frame. Through Bayesian logistic models compiled from 40 years of data and built from 684 planted mangrove stands worldwide, we found that biomass C stock culminated at 71 to 73% to that of intact stands ~20 years after planting. Furthermore, prioritizing mixed-species planting including Rhizophora spp. would maximize C accumulation within the biomass compared to monospecific planting. Despite a 25% increase in the first 5 years following planting, no notable change was observed in the soil C stocks thereafter, which remains at a constant value of 75% to that of intact soil C stock, suggesting that planting effectively prevents further C losses due to land use change. These results have strong implications for mangrove restoration planning and serve as a baseline for future C buildup assessments.

Polaron engineering promotes NIR-II absorption of carbon quantum dots for bioimaging and cancer therapy.

Recent years have witnessed a surge of interest in tuning the optical properties of organic semiconductors for diverse applications. However, achieving control over the optical bandgap in the second near-infrared (NIR-II) window has remained a major challenge. To address this, here we report a polaron engineering strategy that introduces diverse defects into carbon quantum dots (CQDs). These defects induce lattice distortions resulting in the formation of polarons, which can absorb the near-field scattered light. Furthermore, the formed polarons in N-related vacancies can generate thermal energy through the coupling of lattice vibrations, while the portion associated with O-related defects can return to the ground state in the form of NIR-II fluorescence. On the basis of this optical absorption model, these CQDs have been successfully applied to NIR-II fluorescence imaging and photothermal therapy. This discovery could open a promising route for the polarons of organic semiconductor materials as NIR-II absorbers in nanomedical applications.

Changes in productivity partitioning induced by precipitation extremes increase inaccuracy of grassland carbon estimation.

The fraction of net primary productivity (NPP) allocated to belowground organs (fBNPP) in grasslands is a critical parameter in global carbon cycle models; moreover, understanding the effect of precipitation changes on this parameter is vital to accurately estimating carbon sequestration in grassland ecosystems. However, how fBNPP responds to temporal precipitation changes along a gradient from extreme drought to extreme wetness, remains unclear, mainly due to the lack of long-term data of belowground net primary productivity (BNPP) and the fact that most precipitation experiments did not have a gradient from extreme drought to extreme wetness. Here, by conducting both a precipitation gradient experiment (100-500 mm) and a long-term observational study (34 years) in the Inner Mongolia grassland, we showed that fBNPP decreased linearly along the precipitation gradient from extreme drought to extreme wetness due to stronger responses in aboveground NPP to drought and wet conditions than those of BNPP. Our further meta-analysis in grasslands worldwide also indicated that fBNPP increased when precipitation decreased, and the vice versa. Such a consistent pattern of fBNPP response suggests that plants increase the belowground allocation with decreasing precipitation, while increase the aboveground allocation with increasing precipitation. Thus, the linearly decreasing response pattern in fBNPP should be incorporated into models that forecast carbon sequestration in grassland ecosystems; failure to do so will lead to underestimation of the carbon stock in drought years and overestimation of the carbon stock in wet years in grasslands.

Preparation of CoFe@C composite modified electrode for neohesperidin dihydrochalcone sensing and its application in Chinese medicine.

CoFe@C was first prepared by calcining the precursor of CoFe-metal-organic framework-74 (CoFe-MOF-74), then an electrochemical sensor for the determination of neohesperidin dihydrochalcone (NHDC) was constructed, which was stemmed from the novel CoFe@C/Nafion composite film modified glassy carbon electrode (GCE). The CoFe@C/Nafion composite was verified by field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). Electrochemical impedance spectroscopy (EIS) was used to evaluate its electrical properties as a modified material for an electrochemical sensor. Compared with CoFe-MOF-74 precursor modified electrode, CoFe@C/Nafion electrode exhibited a great synergic catalytic effect and extremely increased the oxidation peak signal of NHDC. The effects of various experimental conditions on the oxidation of NHDC were investigated and the calibration plot was tested. The results bespoken that CoFe@C/Nafion GCE has good reproducibility and anti-interference under the optimal experimental conditions. In addition, the differential pulse current response of NHDC was linear with its concentration within the range 0.08 ~ 20 µmol/L, and the linear regression coefficient was 0.9957. The detection limit was as low as 14.2 nmol/L (S/N = 3). In order to further verify the feasibility of the method, it was successfully used to determine the content of NHDC in Chinese medicine, with a satisfactory result, good in accordance with that of high performance liquid chromatography (HPLC).

Dysregulation of hepatic one-carbon metabolism in classical homocystinuria: Implications of redox-sensitive DHFR repression and tetrahydrofolate depletion for pathogenesis and treatment.

Cystathionine beta-synthase-deficient homocystinuria (HCU) is a life-threatening disorder of sulfur metabolism. HCU can be treated by using betaine to lower tissue and plasma levels of homocysteine (Hcy). Here, we show that mice with severely elevated Hcy and potentially deficient in the folate species tetrahydrofolate (THF) exhibit a very limited response to betaine indicating that THF plays a critical role in treatment efficacy. Analysis of a mouse model of HCU revealed a 10-fold increase in hepatic levels of 5-methyl -THF and a 30-fold accumulation of formiminoglutamic acid, consistent with a paucity of THF. Neither of these metabolite accumulations were reversed or ameliorated by betaine treatment. Hepatic expression of the THF-generating enzyme dihydrofolate reductase (DHFR) was significantly repressed in HCU mice and expression was not increased by betaine treatment but appears to be sensitive to cellular redox status. Expression of the DHFR reaction partner thymidylate synthase was also repressed and metabolomic analysis detected widespread alteration of hepatic histidine and glutamine metabolism. Many individuals with HCU exhibit endothelial dysfunction. DHFR plays a key role in nitric oxide (NO) generation due to its role in regenerating oxidized tetrahydrobiopterin, and we observed a significant decrease in plasma NOx (NO2 + NO3) levels in HCU mice. Additional impairment of NO generation may also come from the HCU-mediated induction of the 20-hydroxyeicosatetraenoic acid generating cytochrome CYP4A. Collectively, our data shows that HCU induces dysfunctional one-carbon metabolism with the potential to both impair betaine treatment and contribute to multiple aspects of pathogenesis in this disease.

The impact of low-carbon city pilot policy on urban green technology innovation: Based on government and public perspectives.

Global climate change has caused a series of environmental problems, green technology innovation is necessitating strategic responses, but the impact of low-carbon city pilot policy on urban green technology innovation is unclear. Based on panel data from 285 Chinese cities during 2005-2022, this study employs the Difference in Difference method to examine the impact of low-carbon city policy on urban green technology innovation. The results show that (1) The low-carbon city pilot policy promotes urban green technology innovation. (2) The low-carbon city pilot policy promotes urban green technology innovation through government green input and public engagement. (3) New infrastructure enhances the impact of low-carbon city pilot policy on quantity of green technology innovation. (4) Compared with the Yangtze River Economic Belt, the low-carbon city policy has a greater influence on urban green technology innovation in the Yellow River Basin.The findings provide policy insights for the construction of low-carbon pilot cities.