Decadal shifts in Qingzang Plateau lake carbon dynamics (1970-2020): From predominant carbon sources to emerging sinks.

The evasion of carbon dioxide (CO2) from lakes significantly influences the global carbon equilibrium. Amidst global climatic transformations, the role of Qingzang Plateau (QZP) lakes as carbon (C) sources or sinks remains a subject of debate. Furthermore, accurately quantifying their contribution to the global carbon budget presents a formidable challenge. Here, spanning half a century (1970-2020), we utilize a synthesis of literature and empirical field data to assess the CO2 exchange flux of QZP lakes. We find markedly higher CO2 exchange flux in the southeast lakes than that in the northern and western regions from 1970 to 2000. During this time, both freshwater and saltwater lakes served primarily as carbon sources. The annual CO2 exchange flux was estimated at 2.04 ± 0.37 Tg (Tg) C yr-1, mainly influenced by temperature fluctuations. The CO2 exchange flux patterns underwent a geographical inversion between 2000 and 2020, with increased levels in the west and decreased levels in the east. Notably, CO2 emissions from freshwater lakes diminished, and certain saltwater lakes in the QTP transitioned from carbon sources to sinks. From 2000 to 2020, the annual CO2 exchange flux from QZP lakes is estimated at 1.34 ± 0.50 Tg C yr-1, with solar radiation playing a more pronounced role in carbon emissions. Cumulatively, over the past five decades, QZP lakes have generally functioned as carbon sources. Nevertheless, the total annual CO2 emissions have declined since the year 2000, indicating a potential shift trend from being a carbon source to a sink, mirroring broader patterns of global climate change. These findings not only augment our understanding of the carbon cycle in plateau aquatic systems but also provide crucial data for refining China's carbon budget.

Estimated microplastic stress and potential affiliated toxic elements on phytoplankton in a floodplain-lake system.

Hazards associated with microplastics (MPs) and the pollutants they absorb in freshwater lake ecosystems have become a hot research topic in academia. In this study, in order to investigate potential affiliated MP hazards, lake MP samples were collected from a typical subtropical freshwater lake system in China (Poyang Lake) during the dry season (here, you should show the specific months) to explore their potential toxic element (PTE) response (i.e., exposure to Cu, Pb, and Zn) respective to the ecological environment and resident phytoplankton. Results show that average MP abundance in surface water can reach up to 1800 items m-3, which higher in the Nanjishan Wetland National Nature Reserve (NWNNR) (1175 items m-3). Polyester (i.e., purified terephthalic acid [PTA]) and polyethylene (PE) were the main polymer types found in surface water, fiber was the main MP shape, and most of the MP particle sizes are greater than 100 µm. Moreover, phytoplankton biomass was significantly higher in the NWNNR compared to Poyang Lake's retention basin and water channel. It indicated that MP pollutant status of Poyang Lake is mild; however, the ecological risks that MPs pose should not be ignored. The significant positive correlation between MPs and PTEs indicated that PTE absorption and desorption by MPs may cause potential ecological stress. Although we anticipate no direct link between ecotoxicity and phytoplankton, MPs may have indirect effects on phytoplankton through their regulatory effects on PTE levels in water.

Daidzein alleviates osteoporosis by promoting osteogenesis and angiogenesis coupling.

Background: Postmenopausal osteoporosis and osteoporosis-related fractures are world-wide serious public health problem. Recent studies demonstrated that inhibiting caveolin-1 leads to osteoclastogenesis suppression and protection against OVX-induced osteoporosis. This study aimed to explore the mechanism of caveolin-1 mediating bone loss and the potential therapeutic target. Methods: Thirty C57BL/6 female mice were allocated randomly into three groups: sham or bilateral ovariectomy (OVX) surgeries were performed for mice and subsequently daidzein or vehicle was administrated to animals (control, OVX + vehicle and OVX + daidzein). After 8-week administration, femurs were harvested for Micro-CT scan, histological staining including H&E, immunohistochemistry, immunofluorescence, TRAP. Bone marrow endothelial cells (BMECs) were cultured and treated with inhibitors of caveolin-1 (daidzein) or EGFR (erlotinib) and then scratch wound healing and ki67 assays were performed. In addition, cells were harvested for western blot and PCR analysis. Results: Micro-CT showed inhibiting caveolin-1with daidzein alleviated OVX-induced osteoporosis and osteogenesis suppression. Further investigations revealed H-type vessels in cancellous bone were decreased in OVX-induced mice, which can be alleviated by daidzein. It was subsequently proved that daidzein improved migration and proliferation of BMECs hence improved H-type vessels formation through inhibiting caveolin-1, which suppressed EGFR/AKT/PI3K signaling in BMECs. Conclusions: This study demonstrated that daidzein alleviates OVX-induced osteoporosis by promoting H-type vessels formation in cancellous bone, which then promotes bone formation. Activating EGFR/AKT/PI3K signaling could be the critical reason.

Thermoelectric Properties of One-Pot Hydrothermally Synthesized Solution-Processable PEDOT:PSS/MWCNT Composite Materials.

The combination of organic and inorganic materials has been considered an effective solution for achieving ambient thermoelectric energy harvesting and has been developing rapidly. Here, PEDOT:PSS/MWCNT (PPM) composite hydrogels were synthesized using the self-assembled gelation process of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) and the interaction between PEDOT:PSS and multi-walled carbon nanotubes (MWCNTs) without the addition of any surfactant. After immersion in dimethyl sulfoxide and freeze-drying, the hydrogel is easily dispersed in water and used as a direct ink writing (DIW) 3D printing ink. At room temperature, the PPM-20 printed film with 20 wt% MWCNT solids achieved a maximum power factor of 7.37 µW m-1 K-2 and maintained stable thermoelectric properties during repeated bending cycles. On this basis, a thermoelectric generator (TEG) consisting of five legs was printed, which could be produced to generate an open circuit voltage of 6.4 mV and a maximum output power of 40.48 nW at a temperature gradient of 50 K, confirming its great potential for application in high-performance flexible organic/inorganic thermoelectric materials.

Musculoskeletal Ultrasound Evaluates Renal Injury and Predicts Renal Outcome in Patients with Gout.

Introduction: Kidney injury diagnosis is often delayed in patients with gout. We aimed to determine the characteristics of gout patients with CKD using musculoskeletal ultrasound (MSUS) and whether MSUS could be used as an auxiliary assessment to evaluate kidney injury and predict renal outcome in patients with gout. Methods: Clinical information, laboratory indicators, and MSUS findings were collected and compared between gout-only patients (gout - CKD) and gout patients with CKD (gout + CKD). Multivariate logistic regression was applied to identify risk factors for clinical and MSUS characteristics in both groups. Correlation analysis between MSUS signs and kidney-related indicators was performed, and the effects of MSUS characteristics on renal prognosis were evaluated. Results: In total, 176 patients with gout were included, namely, 89 gout - CKD and 87 gout + CKD cases. After adjusting for confounders, the gout patients with CKD showed more frequent episodes in the previous year, higher ultrasound semiquantitative scores, and more tophi than gout patients without CKD. Additionally, the number of tophi, bone erosion, and synovial hypertrophy measured by MSUS was found to be negatively correlated with the eGFR. The existence of tophi was independently associated with an increased risk of a ≥10% decline in eGFR in the first-year follow-up (OR, 3.56; 95% CI, 1.382-9.176). Conclusions: Ultrasound-detected tophi, bone erosion, and synovial hypertrophy were associated with kidney injury in gout patients. The existence of tophi was associated with faster renal function deterioration. MSUS could be a potential auxiliary diagnostic method to evaluate kidney injury and predict renal outcome in gout patients.

Determining whether Qinghai-Tibet Plateau waterbodies have acted like carbon sinks or sources over the past 20 years.

Half of all of China's lakes are on the Qinghai-Tibet Plateau (QTP), which are mainly distributed at altitudes above 4000 m asl. Being under conditions of progressively intensifying anthropogenic activities and climate change, the debate on whether QTP lakes act as carbon (C) sinks or sources remains unresolved. This study explores QTP lake C exchange processes and characteristics over the past two decades through field monitoring and data integration. Results reveal high lake carbon dioxide (CO2) exchange flux distribution patterns in its western and southern regions and correspondingly low values in its eastern and northern regions. Lake CO2 exchange flux rates also show significant temporal differences where those in the 2000s and 2010s were significantly higher compared to the 2020s. Annual total CO2 emission flux from QTP lakes has increased from 1.60 Tg C a-1 in the 2000s to 6.87 Tg C a-1 in the 2010s before decreasing to 1.16 Tg C a-1 in the 2020s. However, QTP lakes have generally acted as C sinks when annual ice-cover periods are included in the estimation of annual C budgets. Consequently, QTP lakes are gradually evolving towards C sinks. Some small-sized freshwater lakes on the QTP exhibit C sequestration characteristics while low-mid altitude saltwater lakes also act as C sinks. Therefore, owing to the high uncertainties in the estimation of C exchange flux, the QTP lake C sink capacity has been largely underestimated.

Colorimetric sensor arrays for the differentiation of baijiu based on amino-acid-modified gold nanoparticles.

It is of great significance for quality control to realize the discrimination for baijiu from different brands and origins. Strong-aroma-type baijiu (SAB), one of the most important Chinese aroma-type baijiu, exhibits the largest variety and market share. In this study, we proposed colorimetric sensor arrays based on gold nanoparticles (AuNPs) modified with different amino acids (AAs) to recognize the organic acids, and further distinguish different SABs. Three representative AAs, namely methionine (Met), tryptophan (Trp), and histidine (His), were selected to modify the AuNPs surface. The investigation of the effect of the main ingredients of SAB on AA@AuNPs aggregation confirmed that this aggregation mainly resulted from organic acids. Moreover, this aggregation was successfully used for differentiating 11 organic acids. Different pH conditions can not only cause changes of the content of organic acids in baijiu, but also disrupt the balance among flavor substances of baijiu to some extent. Consequently, the AA@AuNPs arrays under two pH conditions have been successfully applied to distinguish 14 kinds of SABs from different brands and origins. The proposed colorimetric sensor method is simple, rapid, and visualized and provides a potential application prospect for the quality control of baijiu and other alcoholic beverages.

Effect of live and inactivated Chlamydomonas reinhardtii on the removal of tetracycline in aquatic environments.

With the development of medical drugs, the widely used tetracycline has brought many adverse effects on the ecosystem and human health. Tetracycline pollution of water environment is becoming more and more serious, and has become an emerging environmental problem. As single celled organisms, microalgae are not only model organisms for risk assessment of aquatic ecosystems, but also can efficiently purify sewage. Microalgae-mediated pollutant remediation has attracted more and more attention from researchers. In this paper, Chlamydomonas reinhardtii (C. reinhardtii) was used to remove tetracycline in aqueous solution, and the removal efficiency and mechanism of microalgae on tetracycline were studied. The results showed that the removal rates of tetracycline by active and inactivated microalgae at a density of 5 × 106 cells·mL-1 were 81.9% and 89.8%, respectively. C. reinhardtii removed tetracycline through biosorption and nonmetabolic processes. Microalgal cell supernatant and hydroxyl radicals could significantly promote the removal of tetracycline. The positively charged tetracycline was electrostatically adsorbed on the microalgae surface and extracellular polymeric substances. Microalgae biomass can promote the production of ROS and enhance the ability of microalgae to remove tetracycline.

Determining whether hydrological processes drive carbon source and sink conversion shifts in a large floodplain-lake system in China.

Lake carbon (C) cycling is a key component of the global C cycle and associated C source and sink processes. The partial pressure of carbon dioxide (pCO2) and carbon dioxide (CO2) exchange flux at the lake-air interface (Fc) are controlled by complex physical, chemical, and biological mechanisms. It would be instructively significant to determine whether hydrological processes drive conversion shifts between C sources and sinks in floodplain-lake systems. Findings from this study show that exogenous input and in situ metabolism related to photosynthesis, respiration, and organic matter degradation were the main driving mechanisms of CO2 absorption and release in a large floodplain-lake system (i.e., Lake Poyang). Moreover, the intense and frequent water-level fluctuations inherent to floodplain-lakes may also have a direct or indirect impact on C cycling processes and CO2 exchange rates in floodplain-lake systems via their effect on physical processes, inorganic C transport, in-situ metabolic processes. We confirmed the potential of C source and sink conversion in floodplain-lakes under hydrological fluctuations, and strengthen the understanding of driving mechanisms of C source and sink conversion in floodplain systems.

Endothelial PDGF-BB/PDGFR-ß signaling promotes osteoarthritis by enhancing angiogenesis-dependent abnormal subchondral bone formation.

The mechanisms that coordinate the shift from joint homeostasis to osteoarthritis (OA) remain unknown. No pharmacological intervention can currently prevent the progression of osteoarthritis. Accumulating evidence has shown that subchondral bone deterioration is a primary trigger for overlying cartilage degeneration. We previously found that H-type vessels modulate aberrant subchondral bone formation during the pathogenesis of OA. However, the mechanism responsible for the elevation of H-type vessels in OA is still unclear. Here, we found that PDGFR-ß expression, predominantly in the CD31hiEmcnhi endothelium, was substantially elevated in subchondral bones from OA patients and rodent OA models. A mouse model of OA with deletion of PDGFR-ß in endothelial cells (ECs) exhibited fewer H-type vessels, ameliorated subchondral bone deterioration and alleviated overlying cartilage degeneration. Endothelial PDGFR-ß promotes angiogenesis through the formation of the PDGFR-ß/talin1/FAK complex. Notably, endothelium-specific inhibition of PDGFR-ß by local injection of AAV9 in subchondral bone effectively attenuated the pathogenesis of OA compared with that of the vehicle-treated controls. Based on the results from this study, targeting PDGFR-ß is a novel and promising approach for the prevention or early treatment of OA.

Severe 25-Hydroxyvitamin D Deficiency May Predict Poor Renal Outcomes in Patients With Biopsy-Proven Diabetic Nephropathy.

Aims: This study aims to investigate the role of 25-hydroxyvitamin D (25(OH)D) levels in predicting renal survival in biopsy-proven diabetic nephropathy (DN) with type 2 diabetes mellitus (DM). Methods: In this retrospective study, a total of 161 biopsy-proven DN patients were enrolled and divided into four groups (normal group: 25(OH)D>20ng/ml; mild group: 10<25(OH)D ≤ 20ng/ml; moderate group: 5<25(OH)D ≤ 10 ng/ml; severe group: 25(OH)D ≤ 5 ng/ml). The effect of the 25(OH)D level on renal survival was evaluated by multivariate Cox regression. Results: A total of 161 type 2 DM patients with biopsy-proven DN were enrolled in this study. Patients with lower 25(OH)D levels had higher serum creatinine, urinary albumin creatinine ratio (UACR), total cholesterol, and parathyroid hormone levels as well as lower estimated glomerular filtration rate (eGFR), hemoglobin, albumin, and calcium levels and were more prone to diabetic retinopathy (DR). Rather than proteinuria and renal function, glomerular class and interstitial fibrosis and tubular atrophy (IFTA) had a significant correlation with 25(OH)D levels. Multivariate Cox regression indicated that severe deficiency of 25(OH)D levels was associated with adverse renal outcomes. Compared to the level in the normal group, after adjusting for clinicopathological characteristics, a lower 25(OH)D level remained a risk factor for renal outcomes. The HRs were 3.446 (95% CI 0.366-32.406, p=0.279) for the mild group, 8.009 (95% CI 0.791-81.102, p=0.078) for the moderate group, and 14.957(95%CI 1.364-163.995, P=0.027) for the severe group. Conclusion: Levels of 25(OH)D less than 5 ng/ml were correlated with worse renal function, more pathological injury and poorer renal prognosis in patients with biopsy-proven DN.

A novel dual-channel fluorescence sensor array based on the reaction of o-phenylenediamine/3,4-diaminotoluene and pyrocatechol for Baijiu discrimination.

An effective method to discriminate Baijiu carries important applications for grade identification and quality control in the Baijiu industry. Herein, we report on a novel and straightforward dual-channel fluorescence sensor array for flavor compounds (FCs) and Chinese Baijiu discrimination. Unit 1 (U1) is the reaction between o-phenylenediamine (OPD) and pyrocatechol (ODHB), and unit 2 (U2) is the reaction between 3,4-diaminotoluene (3,4-DAT) and ODHB. The fluorescent products were changed via FCs in Baijiu relying on the influence of protonation of the amino group on OPD/3,4-DAT and chemical reactions. The array successfully achieves qualitative and quantitative identification of FCs with low detection limits and wide linear ranges. In addition, qualitative identification of 0.7 mmol/L FCs in Baijiu is achieved. Finally, this is applied to discriminate 32 Baijius varieties with different aromas, brands, and grades. The fluorescence sensor array is reliable and straightforward for FCs identification and Baijius discrimination, which is of great significance for authenticity identification in the Baijiu industry.

Phytoplankton community composition, carbon sequestration, and associated regulatory mechanisms in a floodplain lake system.

Phytoplankton contribute approximately 50% to the global photosynthetic carbon (C) fixation. However, our understanding of the corresponding C sequestration capacity and driving mechanisms associated with each individual phytoplankton taxonomic group is limited. Particularly in the hydrologically dynamic system with highly complex surface hydrological processes (floodplain lake systems). Through investigating seasonal monitoring data in a typical floodplain lake system and estimation of primary productivity of each phytoplankton taxonomic group individually using novel equations, this study proposed a phytoplankton C fixation model. Results showed that dominant phytoplankton communities had a higher gross carbon sequestration potential (CSP) (9.50 ± 5.06 Gg C each stage) and gross primary productivity (GPP) (65.46 ± 25.32 mg C m-2 d-1), but a lower net CSP (-1.04 ± 0.79 Gg C each stage) and net primary productivity (NPP) (-5.62 ± 4.93 mg C m-3 d-1) than rare phytoplankton communities in a floodplain lake system. Phytoplanktonic GPP was high (317.94 ± 73.28 mg C m-2 d-1) during the rainy season and low (63.02 ± 9.65 mg C m-2 d-1) during the dry season. However, their NPP reached the highest during the rising-water stage and the lowest during the receding-water stage. Findings also revealed that during the rainy season, high water levels (p = 0.56**) and temperatures (p = 0.37*) as well as strong solar radiation (p = 0.36*) will increase photosynthesis and accelerate metabolism and respiration of dominant phytoplankton communities, then affect primary productivity and CSP. Additionally, water level fluctuations drive changes in nutrients (p = -0.57*) and metals (p = -0.68*) concentrations, resulting in excessive nutrients and metals slowing down phytoplankton growth and reducing GPP. Compared with the static water lake system, the floodplain lake system with a lower net CSP became a heterotrophic C source.

Enhanced Cr(VI) stabilization in soil by chitosan/bentonite composites.

In this study, chitosan/bentonite composites (CSBT) was synthesized and applied to the immobilization of chromium in the soil. The influence of passivating agents on various forms of chromium was investigated by batch experiment. The results showed that CSBT could reduce the content of exchangeable form and oxidizable form, while increase the content of residual form of chromium. The addition of 0.2 g·kg-1 CSBT had the best effect, with the concentration of exchangeable, reducible and oxidizable form decreased by 46.74%, 8.15%, and 14.46%, respectively. During the experiment time, the passivation effect increased rapidly within 14 days, and the content of residual form in the total Cr increased from 0.76% to 14.23%, the equilibrium was reached at the 28th day and was basically maintained in the subsequent period. CSBT had little impact on soil pH, and soil pH maintained constant during the experiment period. The amino, carboxyl and hydroxyl groups of CSBT promoted the conversion of available chromium to residual state in soil, and reduced the bioavailability of chromium in soil.

The "Regulator" Function of Viruses on Ecosystem Carbon Cycling in the Anthropocene.

Viruses act as "regulators" of the global carbon cycle because they impact the material cycles and energy flows of food webs and the microbial loop. The average contribution of viruses to the Earth ecosystem carbon cycle is 8.6‰, of which its contribution to marine ecosystems (1.4‰) is less than its contribution to terrestrial (6.7‰) and freshwater (17.8‰) ecosystems. Over the past 2,000 years, anthropogenic activities and climate change have gradually altered the regulatory role of viruses in ecosystem carbon cycling processes. This has been particularly conspicuous over the past 200 years due to rapid industrialization and attendant population growth. The progressive acceleration of the spread and reproduction of viruses may subsequently accelerate the global C cycle.

Clinical and Histological Predictors of Renal Survival in Patients with Biopsy-Proven Diabetic Nephropathy.

INTRODUCTION: Clinical indicators or pathological features alone cannot reliably predict renal survival in patients with biopsy-confirmed diabetic nephropathy (DN). Therefore, this analysis sought to develop and validate a predictive model incorporating both clinical and pathological markers to predict renal outcomes in patients with biopsy-confirmed DN. METHODS: A predictive nomogram was developed based upon data pertaining to 194 patients with biopsy-confirmed DN. The prognostic relevance of individual clinicopathological variables was assessed through univariate and multivariate Cox regression analyses. A prognostic nomogram was then developed and validated based upon concordance (C)-index values and calibration curves. Internal validation was conducted through bootstrap resampling, while the clinical utility of this model was assessed via a decision curve analysis (DCA) approach. RESULTS: Nephrotic-range 24-h proteinuria, late-stage CKD, glomerular classification III-IV, and IFTA score 2-3 were all identified as independent predictors of poor renal outcomes in DN patients and were incorporated into our final nomogram. Calibration curves revealed good agreement between predicted and actual 3- and 5-year renal survival in DN patients with the C-index value for this nomogram at 0.845 (95% CI: 0.826-0.864). DCA revealed that our nomogram was superior to models based solely upon clinical indicators. CONCLUSION: A predictive nomogram incorporating clinical and pathological indicators was developed and validated for the prediction of renal survival outcomes in patients with biopsy-confirmed DN. This model will be of value to clinicians, as it can serve as an easy-to-use and reliable tool for physicians to guide patient management based on individualized risk.

In Vivo Intravascular Optical Coherence Tomography (IVOCT) Structural and Blood Flow Imaging Based Mechanical Simulation Analysis of a Blood Vessel.

INTRODUCTION: Computer modelling of blood vessels based on biomedical imaging provides important hemodynamic and biomechanical information for vascular disease studies and diagnosis. However due to lacking well-defined physiological blood flow profiles, the accuracy of the simulation results is often not guaranteed. Flow velocity profiles of a specific cross section of a blood vessel were obtained by in vivo Doppler intravascular optical coherence tomography (IVOCT) lately. However due to the influence of the catheter, the velocity profile imaged by IVOCT can't be applied to simulation directly. METHODS: A simulation-experiment combined method to determine the inlet flow boundary based on in vivo porcine carotid Doppler IVOCT imaging is proposed. A single conduit carotid model was created from the 3D IVOCT structural images using an image processing-computer aided design combined method. RESULTS: With both high- resolution arterial model and near physiological blood flow profile, stress analysis by fluid-structure interaction and computational fluid dynamics were performed. The influence of the catheter to the wall shear stress, the hemodynamics and the stresses of the carotid wall under the measured inlet flow and various outlet pressure boundary conditions, are analyzed. CONCLUSION: This study provides a solution to the difficulty of getting inlet flow boundary for numerical simulation of arteries. It paves the way for developing IVOCT based vascular stress analysis and imaging methods for the studies and diagnosis of vascular diseases.

Electronic nature of charge density wave and electron-phonon coupling in kagome superconductor KV3Sb5.

The Kagome superconductors AV3Sb5 (A = K, Rb, Cs) have received enormous attention due to their nontrivial topological electronic structure, anomalous physical properties and superconductivity. Unconventional charge density wave (CDW) has been detected in AV3Sb5. High-precision electronic structure determination is essential to understand its origin. Here we unveil electronic nature of the CDW phase in our high-resolution angle-resolved photoemission measurements on KV3Sb5. We have observed CDW-induced Fermi surface reconstruction and the associated band folding. The CDW-induced band splitting and the associated gap opening have been revealed at the boundary of the pristine and reconstructed Brillouin zones. The Fermi surface- and momentum-dependent CDW gap is measured and the strongly anisotropic CDW gap is observed for all the V-derived Fermi surface. In particular, we have observed signatures of the electron-phonon coupling in KV3Sb5. These results provide key insights in understanding the nature of the CDW state and its interplay with superconductivity in AV3Sb5 superconductors.

Vertically stratified water source characteristics and associated driving mechanisms of particulate organic carbon in a large floodplain lake system.

Particulate organic carbon (POC) is an important component of lake organic carbon (C) pools, of which different factors drive vertical distributions and sources. This study used the dual stable isotope (δ13C and δ15N) approach to investigate vertical POC sources and drivers in a large floodplain lake system. Findings showed that POC composition gradually changed from endogenous dominant to exogenous dominant sequentially from the surface layer to the bottom layer of Lake Poyang. Environmental factors associated with phytoplankton photosynthesis as well as nutrient levels primarily drove surface POC. Moreover, soil erosion, sediment deposition, and resuspension strongly affected POC distribution and composition in the middle and bottom layers of the lake. POC sources were also affected by factors associated with vertical mixing, such as wind speed and water depth. Litter from C3 plants significantly contributed to POC concentrations in the middle and bottom layers of the lake. Results from this study can benefit our overall understanding of the potential driving mechanisms of lake C cycling processes, aquatic ecosystem functions, and pollutant migration.

Furfural and organic acid targeted carbon dot sensor array for the accurate identification of Chinese baijiu.

Baijiu quality control has always been a major challenge for researchers. In this paper, taking furfural which is closely related to baijiu brewing process and organic acids related to baijiu fermentation process and microorganism types as the main discriminating factors, a carbon dot (CDs) sensor array targeting furfural and organic acids was constructed to identify 41 kinds of baijiu. Through the fluorescence response investigation of CDs synthesized by isomers of benzenediol, aminophenol, and phenylenediamine to different baijiu, two CDs synthesized by meta-benzene substitutions containing -NH2 were selected to build a fluorescence sensor array. Due to the aggregation-induced enhancement effect between furfural and the CDs, and the protonation of organic acid and the CDs, different fluorescence changes were observed, the sensor array combined with partial least squares regression could quantitatively analyze furfural and organic acids. What is more, semi-quantitative analysis of furfural and lactic acid in baijiu was performed. Owing to the interaction of the two CDs with furfural and organic acids in baijiu, the sensor array could accurately identify different baijiu through linear discriminant analysis. This sensor array has potential applications in the quantitative analysis of flavor substances in other alcoholic beverages, moreover, this method could provide a quick response and practical tool for real-time quality control monitoring in the baijiu industry.