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1.
Anticancer Drugs ; 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38728054

RESUMO

Up to 80% of biliary tract cancer (BTC) patients relapse within 3 years after surgery and the efficacy of second-line treatment remains dismal for patients who progressed on gemcitabine and cisplatin chemotherapy. Median overall survival of patients with palliative chemotherapy is less than 1 year. The feasibility and safety of targeted therapies plus immunotherapies remain scanty currently, and patients with recurrent or advanced BTCs often experience a rapid decline in Eastern Cooperative Oncology Group (ECOG) performance status. This case report is the first report suggesting a 17-month progression-free survival (PFS), partial response, and another 11-month PFS after progressive disease of anlotinib plus toripalimab in advanced BTC with high ECOG performance status. We report a 67-year-old Chinese male with BTC. He was observed with progressive disease after surgical resection, adjuvant chemotherapy, palliative chemotherapy, and diagnosed with American Joint Committee on Cancer clinical stage IV (cT3N0M1) extrahepatic BTC. The patient experienced a rapid decline in performance status, and he received oral anlotinib and toripalimab with informed consent. MRI scans showed partial response on 22 June 2022. PET-CT showed that tumor activity has been inhibited on 8 March 2023. He achieved 17 months of PFS. Although the patient developed solitary lung metastasis, he had a continuous survival benefit from treatment of anlotinib plus toripalimab after lung radiotherapy. Until the writing of the case draft, he had achieved another 11 months of PFS. The present case suggests that anlotinib plus toripalimab might be a potential effective treatment for advanced BTCs patients with high ECOG performance status.

2.
Am J Kidney Dis ; 2024 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-38518919

RESUMO

RATIONALE & OBJECTIVE: Hemoglobin A1c (HbA1c) is widely used to estimate glycemia, yet it is less reliable in patients with chronic kidney disease (CKD). There is growing interest in the complementary use of glycated albumin (GA) to improve glycemic monitoring and risk stratification. However, whether GA associates with clinical outcomes in a non-dialysis-dependent CKD population remains unknown. STUDY DESIGN: Prospective cohort study. SETTING & PARTICIPANTS: 3,110 participants with CKD from the Chronic Renal Insufficiency Cohort study. EXPOSURE: Baseline GA levels. OUTCOME: Incident end-stage kidney disease (ESKD), cardiovascular disease (CVD) events, and all-cause mortality. ANALYTICAL APPROACH: Cox proportional hazards regression. RESULTS: Participant characteristics included mean age 59.0±10.8 SD years; 1,357 (43.6%) female; and 1,550 (49.8%) with diabetes. The median GA was 18.7% (IQR, 15.8%-23.3%). During an average 7.9-year follow-up, there were 980 ESKD events, 968 CVD events, and 1,084 deaths. Higher GA levels were associated with greater risks of all outcomes, regardless of diabetes status: hazard ratios for ESKD, CVD, and death among participants with the highest quartile compared with quartile 2 (reference) were 1.42 (95% CI, 1.19-1.69), 1.67 (95% CI, 1.39-2.01), and 1.63 (95% CI, 1.37-1.94), respectively. The associations with CVD and death appeared J-shaped, with increased risk also seen at the lowest GA levels. Among patients with coexisting CKD and diabetes, the associations of GA with outcomes remained significant even after adjusting for HbA1c. For each outcome, we observed a significant increase in the fraction of new prognostic information when both GA and HbA1c were added to models. LIMITATIONS: Lack of longitudinal GA measurements; and HbA1c measurements were largely unavailable in participants without diabetes. CONCLUSIONS: Among patients with CKD, GA levels were independently associated with risks of ESKD, CVD, and mortality, regardless of diabetes status. GA added prognostic value to HbA1c among patients with coexisting CKD and diabetes. PLAIN-LANGUAGE SUMMARY: Hemoglobin A1c (HbA1c) is widely used to estimate glycemia, yet it is less reliable in patients with chronic kidney disease (CKD). There is growing interest in the complementary use of glycated albumin (GA) to improve glycemic monitoring and risk stratification. However, whether GA associates with clinical outcomes in a non-dialysis-dependent CKD population remains unknown. In this cohort study of 3,110 individuals with non-dialysis-dependent CKD, GA levels were independently associated with risks of end-stage kidney disease, cardiovascular disease (CVD), and mortality. The associations with CVD and mortality appeared to be J-shaped. Among patients with coexisting CKD and diabetes, GA added prognostic value to HbA1c. Thus, GA may be a valuable complementary test to HbA1c in patients with CKD.

3.
Org Lett ; 26(9): 1914-1919, 2024 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-38420924

RESUMO

A catalytic kinetic resolution of sulfoximines has been developed through chiral phosphoric acid-catalyzed intramolecular dehydrative cyclizations. A variety of racemic sulfoximines bearing an ortho-amidophenyl moiety underwent asymmetric dehydrative cyclizations using this method, yielding both the recovered sulfoximines and benzothiadiazine-1-oxide products with good to high enantioselectivities (with s-factor up to 61). The diverse derivatizations of the chiral products into a wide range of S-stereogenic center-containing S,N-heterocycles have demonstrated the value of this method.

4.
Stress Health ; 40(1): e3262, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37226429

RESUMO

Adverse childhood experiences (ACEs) have been associated with poor HIV testing in adulthood yet, they have not been extensively described in those at increased risk for HIV. Cross-sectional analysis data (n = 204,231) on ACEs and HIV testing were obtained from the 2019-2020 Behavioural Risk Factor Surveillance Survey. Weighted logistic regression models were used to access the association of ACEs exposure, ACEs score, and ACEs type with HIV testing among adults with HIV risk behaviours, and stratified analysis was also performed to examine gender differences. The results indicated the overall rate of HIV testing was 38.8% and was higher among those with HIV risk behaviours (64.6%) than those without (37.2%). In populations with HIV risk behaviours, the negative association of HIV testing with ACEs exposure, ACEs score, and ACEs type was identified. Relative to those without ACEs, adults who were exposed to ACEs might decrease the rate of HIV testing, participants with ≥4 ACEs scores were less likely to have HIV testing, and childhood exposure to sexual abuse had the greatest impact on HIV testing. For both males and females, childhood exposure to ACEs was associated with lower odds of HIV testing and ACEs score ≥4 had the most robust associations with HIV testing. For males, those who experienced witnessed domestic violence had the lowest odds of HIV testing but the odds of engaging in HIV testing for females were the lowest among those who experienced childhood sexual abuse.


Assuntos
Experiências Adversas da Infância , Infecções por HIV , Adulto , Masculino , Feminino , Humanos , HIV , Estudos Transversais , Sistema de Vigilância de Fator de Risco Comportamental , Assunção de Riscos
5.
Food Chem ; 440: 138174, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38160593

RESUMO

Aiming to assess the effects of lard oil (LO) and fish oil (FO) on the nutritional value of mud crabs (Scylla paramamosain), non-targeted lipidomics analysis was performed on the muscle of crabs after eight weeks of feeding trail. Compared to FO, dietary LO reduced the content of phosphatidylethanolamine (PE) and phosphatidylserine (PS) with 18:0 bound at sn-1/3 site, the content of ether phospholipids containing 20:5n-3 (EPA) and 22:6n-3 (DHA) combined at sn-2 site, and increased the content of ether PE containing 18:0 and 18:1n-9. Furthermore, the deposition of 16:0, 16:1n-7, 18:2n-6, 18:3n-3, 20:4n-6, EPA and DHA at each site of PE, PS, phosphatidylcholine and/or triacylglycerols were reduced by dietary LO, while the DHA content at the sn-2 position of PE was increased. In conclusion, the nutritional value of mud crabs was reduced by dietary LO with the manifestation of variation in FA composition and positional distribution on phospholipids.


Assuntos
Braquiúros , Gorduras Insaturadas na Dieta , Gorduras na Dieta , Animais , Óleos de Peixe/metabolismo , Braquiúros/metabolismo , Ácidos Graxos/metabolismo , Lipidômica , Músculos/metabolismo , Nutrientes
6.
Angew Chem Int Ed Engl ; 63(7): e202315624, 2024 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-38151704

RESUMO

Graphite (Gr) has been considered as the most promising anode material for potassium-ion batteries (PIBs) commercialization due to its high theoretical specific capacity and low cost. However, Gr-based PIBs remain unfeasible at low temperature (LT), suffering from either poor kinetics based on conventional carbonate electrolytes or K+ -solvent co-intercalation issue based on typical ether electrolytes. Herein, a high-performance Gr-based LT rechargeable PIB is realized for the first time by electrolyte chemistry. Applying unidentate-ether-based molecule as the solvent dramatically weakens the K+ -solvent interactions and lowers corresponding K+ de-solvation kinetic barrier. Meanwhile, introduction of steric hindrance suppresses co-intercalation of K+ -solvent into Gr, greatly elevating operating voltage and cyclability of the full battery. Consequently, the as-prepared Gr||prepotassiated 3,4,9,10-perylene-tetracarboxylicacid-dianhydride (KPTCDA) full PIB can reversibly charge/discharge between -30 and 45 °C with a considerable energy density up to 197 Wh kgcathode -1 at -20 °C, hopefully facilitating the development of LT PIBs.

7.
Nat Commun ; 14(1): 6006, 2023 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-37752165

RESUMO

In contrast to conventional batteries, anode-free configurations can extend cell-level energy densities closer to the theoretical limit. However, realizing alkali metal plating/stripping on a bare current collector with high reversibility is challenging, especially at low temperature, as an unstable solid-electrolyte interphase and uncontrolled dendrite growth occur more easily. Here, a low-temperature anode-free potassium (K) metal non-aqueous battery is reported. By introducing Si-O-based additives, namely polydimethylsiloxane, in a weak-solvation low-concentration electrolyte of 0.4 M potassium hexafluorophosphate in 1,2-dimethoxyethane, the in situ formed potassiophilic interface enables uniform K deposition, and offers K||Cu cells with an average K plating/stripping Coulombic efficiency of 99.80% at -40 °C. Consequently, anode-free Cu||prepotassiated 3,4,9,10-perylene-tetracarboxylicacid-dianhydride full batteries achieve stable cycling with a high specific energy of 152 Wh kg-1 based on the total mass of the negative and positive electrodes at 0.2 C (26 mA g-1) charge/discharge and -40 °C.

8.
J Cancer Res Clin Oncol ; 149(15): 13995-14014, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37543978

RESUMO

BACKGROUND: Colorectal cancer is the second leading cause of cancer-related deaths, which imposes a significant societal burden. Regular screening and emerging molecular tumor markers have important implications for detecting the progression and development of colorectal cancer. Disulfidptosis is a newly defined type of programmed cell death triggered by abnormal accumulation of disulfide compounds in cells that stimulate disulfide stress. Currently, there is no relevant discussion on this mechanism and colorectal cancer. METHODS: We classified the disulfidptosis-related subtypes of colorectal cancer using bioinformatics methods. Through secondary clustering of differentially expressed genes between subtypes, we identified characteristic genes of the disulfidptosis subtype, constructed a prognostic model, and searched for potential biomarkers through clinical validation. RESULTS: Using disulfidptosis-related genes collected from the literature, we classified colorectal cancer patients from public databases into three subtypes. The differentially expressed genes between subtypes were clustered into three gene subtypes, and eight characteristic genes were screened to construct a prognostic model. CONCLUSION: The disulfidptosis mechanism has important value in the classification of colorectal cancer patients, and characteristic genes selected based on this mechanism can serve as a new potential biological marker for colorectal cancer.

10.
Angew Chem Int Ed Engl ; 62(33): e202307122, 2023 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-37370245

RESUMO

Potassium-ion batteries (PIBs) are promising for cryogenic energy storage. However, current researches on low-temperature PIBs are limited to half cells utilizing potassium metal as an anode, and realizing rechargeable full cells is challenged by lacking viable anode materials and compatible electrolytes. Herein, a hard carbon (HC)-based low-temperature potassium-ion full cell is successfully fabricated for the first time. Experimental evidence and theoretical analysis revealed that potassium storage behaviors of HC anodes in the matched low-temperature electrolyte involve defect adsorption, interlayer co-intercalation, and nanopore filling. Notably, these unique potassiation processes exhibited low interfacial resistances and small reaction activation energies, enabling an excellent cycling performance of HC with a capacity of 175 mAh g-1 at -40 °C (68 % of its room-temperature capacity). Consequently, the HC-based full cells demonstrated impressive rechargeability and high energy density above 100 Wh kg-1 cathode at -40 °C, representing a significant advancement in the development of PIBs.

11.
Curr Issues Mol Biol ; 45(5): 4480-4494, 2023 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-37232753

RESUMO

Parkinson's disease is a severe neurodegenerative disorder. Currently, deep brain electrical stimulation (DBS) is the first line of surgical treatment. However, serious neurological impairments such as speech disorders, disturbances of consciousness, and depression after surgery limit the efficacy of treatment. In this review, we summarize the recent experimental and clinical studies that have explored the possible causes of neurological deficits after DBS. Furthermore, we tried to identify clues from oxidative stress and pathological changes in patients that could lead to the activation of microglia and astrocytes in DBS surgical injury. Notably, reliable evidence supports the idea that neuroinflammation is caused by microglia and astrocytes, which may contribute to caspase-1 pathway-mediated neuronal pyroptosis. Finally, existing drugs and treatments may partially ameliorate the loss of neurological function in patients following DBS surgery by exerting neuroprotective effects.

13.
Front Med (Lausanne) ; 10: 1103071, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36744138

RESUMO

Background: Vasovagal reactions are common amongst patients with a fear of needles receiving injections or during venipuncture, but they are rarely studied in healthy people undergoing earlobe piercing. The purpose of this prospective study was to evaluate the incidence and the features of vasovagal reactions observed during earlobe piercing. Methods: Thousand eight hundred and sixty six participants aged older than 13 years had their earlobes pierced in our department from January 2020 to January 2022. When vasovagal reactions occurred during the procedure (e.g., dizziness, pallor, diaphoresis, and faintness, etc.), they were recorded and more detailed demographic information was collected. Results: A total of 196 cases of vasovagal reactions were reported in females amongst 1,866 participants, including 58 who actually lost consciousness during earlobe piercing. The incidence of vasovagal reactions and vasovagal syncope was 10.5 and 3.11% respectively. All syncopal reactions occurred in persons younger than 30 years. Conclusion: Vasovagal syncope is often very sudden and occurs without warning. Practitioners need to be familiar with these reactions, and prevent people from an unpredictable fall and subsequent injury during ear piercing.

14.
J Am Soc Nephrol ; 34(5): 876-885, 2023 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-36757153

RESUMO

SIGNIFICANCE STATEMENT: Protein carbamylation, a nonenzymatic post-translational protein modification partially driven by elevated blood urea levels, associates with mortality and adverse outcomes in patients with ESKD on dialysis. However, little is known about carbamylation's relationship to clinical outcomes in the much larger population of patients with earlier stages of CKD. In this prospective observational cohort study of 3111 individuals with CKD stages 2-4, higher levels of carbamylated albumin (a marker of protein carbamylation burden) were associated with a greater risk of developing ESKD and other significant adverse clinical outcomes. These findings indicate that protein carbamylation is an independent risk factor for CKD progression. They suggest that further study of therapeutic interventions to prevent or reduce carbamylation is warranted. BACKGROUND: Protein carbamylation, a post-translational protein modification partially driven by elevated blood urea levels, associates with adverse outcomes in ESKD. However, little is known about protein carbamylation's relationship to clinical outcomes in the much larger population of patients with earlier stages of CKD. METHODS: To test associations between protein carbamylation and the primary outcome of progression to ESKD, we measured baseline serum carbamylated albumin (C-Alb) in 3111 patients with CKD stages 2-4 enrolled in the prospective observational Chronic Renal Insufficiency Cohort study. RESULTS: The mean age of study participants was 59 years (SD 10.8); 1358 (43.7%) were female, and 1334 (42.9%) were White. The mean eGFR at the time of C-Alb assessment was 41.8 (16.4) ml/minute per 1.73 m 2 , and the median C-Alb value was 7.8 mmol/mol (interquartile range, 5.8-10.7). During an average of 7.9 (4.1) years of follow-up, 981 (31.5%) individuals developed ESKD. In multivariable adjusted Cox models, higher C-Alb (continuous or quartiles) independently associated with an increased risk of ESKD. For example, compared with quartile 1 (C-Alb ≤5.80 mmol/mol), those in quartile 4 (C-Alb >10.71 mmol/mol) had a greater risk for ESKD (adjusted hazard ratio, 2.29; 95% confidence interval, 1.75 to 2.99), and the ESKD incidence rate per 1000 patient-years increased from 15.7 to 88.5 from quartile 1 to quartile 4. The results remained significant across numerous subgroup analyses, when treating death as a competing event, and using different assessments of eGFR. CONCLUSIONS: Having a higher level of protein carbamylation as measured by circulating C-Alb is an independent risk factor for ESKD in individuals with CKD stages 2-4. PODCAST: This article contains a podcast at https://dts.podtrac.com/redirect.mp3/www.asn-online.org/media/podcast/JASN/2023_04_24_JSN_URE_EP22_042423.mp3.


Assuntos
Falência Renal Crônica , Carbamilação de Proteínas , Insuficiência Renal Crônica , Albumina Sérica , Humanos , Masculino , Pessoa de Meia-Idade , Falência Renal Crônica/complicações , Insuficiência Renal Crônica/complicações , Albumina Sérica/metabolismo , Progressão da Doença , Taxa de Filtração Glomerular , Feminino , Idoso
15.
Diabetes Care ; 46(1): 130-137, 2023 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-36399777

RESUMO

OBJECTIVE: Glycated hemoglobin (HbA1c) can predict risk for microvascular complications in patients with diabetes. However, HbA1c's reliability in chronic kidney disease (CKD) has been questioned, with concerns including competition from another posttranslational protein modification, carbamylation, acting on the same amino groups as glycation, and anemia with reduced erythrocyte lifespans leading to altered glycation accumulation. We investigated whether carbamylation and anemia modify the impact of HbA1c on renal outcomes in patients with diabetes and CKD. RESEARCH DESIGN AND METHODS: In 1,516 participants from the Chronic Renal Insufficiency Cohort study with diabetes and CKD, Cox regression models were applied to evaluate the association between HbA1c and CKD progression (composite of end-stage kidney disease or 50% decline in estimated glomerular filtration rate [eGFR]), stratified by carbamylated albumin (C-Alb) quartiles and anemia. RESULTS: The mean eGFR was 38.1 mL/min/1.73 m2, mean HbA1c was 7.5% (58 mmol/mol), and median C-Alb was 8.4 mmol/mol. HbA1c was lower in the higher C-Alb quartiles. During a median follow-up of 6.9 years, 763 participants experienced CKD progression. Overall, higher HbA1c was associated with an increased risk of CKD progression (adjusted hazard ratio 1.07 [95% CI 1.02-1.13]). However, using stratified analyses, HbA1c was no longer associated with CKD progression in the highest C-Alb quartile, but did show a monotonic increase in CKD progression risk across each lower C-Alb quartile (P-interaction = 0.022). Anemia also modified the association between HbA1c and CKD progression (P-interaction = 0.025). CONCLUSIONS: In patients with coexisting diabetes and CKD, the association between HbA1c and CKD progression is modified by carbamylation and anemia.


Assuntos
Anemia , Diabetes Mellitus , Insuficiência Renal Crônica , Humanos , Hemoglobinas Glicadas , Estudos de Coortes , Carbamilação de Proteínas , Reprodutibilidade dos Testes , Progressão da Doença , Insuficiência Renal Crônica/complicações , Taxa de Filtração Glomerular
16.
J Am Chem Soc ; 145(1): 717-724, 2023 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-36548984

RESUMO

Compared with layered materials such as graphite and transitional metal dichalcogenides with highly anisotropic in-plane covalent bonds, freestanding metallic two-dimensional (2D) films with atomic thickness are intrinsically more difficult to achieve. The omnidirectional nature of typical metallic bonds prevents the formation of highly anisotropic atomically thin metallic layers. Herein, we report a ligand regulation strategy to stabilize monoatomic platinum layers by forming a unique lamellar superlattice structure with self-assembled organic ligand layers. We show that the interlayer spacings and coordination environments could be systematically tuned by varying programmable molecular ligands with the designed length and structural motifs, which further modulate the electronic states and catalytic performances. The strategy can be extended for preparing lamellar superlattices with monoatomic metallic layers from silver and gold. Such general and delicate synthetic control provides an exciting model system for systematic investigation of the intriguing structure-property correlation of monoatomic layers and promises a molecular design pathway for heterogeneous catalysts.

17.
Org Biomol Chem ; 21(2): 279-283, 2023 01 04.
Artigo em Inglês | MEDLINE | ID: mdl-36484347

RESUMO

A novel and efficient palladium-catalyzed cascade cyclization to indoloquinoline derivatives in one pot has been developed by using allenamide derivatives and 2-iodoanilines as the key building blocks. The process involved two cyclizations: intramolecular cyclization/π-allylic substitution and intramolecular 6-endo Heck cyclization. Furthermore, dihydrobenzofuro[2,3-b]quinoline derivatives could also be achieved via this strategy using allenyl ethers instead of allenamides. The readily available substrates, mild conditions, high efficiency and step economy make this strategy a promising method in the synthesis of polycyclic motifs.


Assuntos
Compostos de Anilina , Paládio , Ciclização , Paládio/química , Catálise
18.
Hereditas ; 159(1): 42, 2022 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-36419192

RESUMO

BACKGROUND: Ulcerative colitis (UC) refers to an intractable intestinal inflammatory disease. Its increasing incidence rate imposes a huge burden on patients and society. The UC etiology has not been determined, so screening potential biomarkers is critical to preventing disease progression and selecting optimal therapeutic strategies more effectively. METHODS: The microarray datasets of intestinal mucosal biopsy of UC patients were selected from the GEO database, and integrated with R language to screen differentially expressed genes and draw proteins interaction network diagrams. GO, KEGG, DO and GSEA enrichment analyses were performed to explore their biological functions. Through machine learning and WGCNA analysis, targets that can be used as UC potential biomarkers are screened out. ROC curves were drawn to verify the reliability of the results and predicted the mechanism of marker genes from the aspects of immune cell infiltration, co-expression analysis, and competitive endogenous network (ceRNA). RESULTS: Two datasets GSE75214 and GSE87466 were integrated for screening, and a total of 107 differentially expressed genes were obtained. They were mainly related to biological functions such as humoral immune response and inflammatory response. Further screened out five marker genes, and found that they were associated with M0 macrophages, quiescent mast cells, M2 macrophages, and activated NK cells in terms of immune cell infiltration. The co-expression network found significant co-expression relationships between 54 miRNAs and 5 marker genes. According to the ceRNA hypothesis, NEAT1-miR-342-3p/miR-650-SLC6A14, NEAT1-miR-650-IRAK3, and XIST-miR-342-3p-IRAK3 axes were found as potential regulatory pathways in UC. CONCLUSION: This study screened out five biomarkers that can be used for the diagnosis and treatment of UC, namely SLC6A14, TIMP1, IRAK3, HMGCS2, and APOBEC3B. Confirmed that they play a role in the occurrence and development of UC at the level of immune infiltration, and proposed a potential RNA regulatory pathway that controls the progression of UC.


Assuntos
Colite Ulcerativa , MicroRNAs , Humanos , Colite Ulcerativa/diagnóstico , Colite Ulcerativa/genética , Reprodutibilidade dos Testes , Aprendizado de Máquina , Biomarcadores , Citidina Desaminase , Antígenos de Histocompatibilidade Menor
19.
J Environ Manage ; 319: 115681, 2022 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-35816961

RESUMO

Water eutrophication is a serious global issue because of excess external and internal nutrient inputs. Understanding the intensity and contribution of internal nitrogen (N) and phosphorus (P) loading in deep-water ecosystems is of great significance for water body eutrophication management. In this study, we combined intact sediment core incubation, high-resolution peeper (HR-Peeper) sampling, and analysis of N and P forms and other environmental factors in the water column and sediments to evaluate the contributions of internal N and P loading to water eutrophication by N and P fluxes across the sediment-water interface (SWI) of the Panjiakou Reservoir (PJKR), a deep-water ecosystem where eutrophication threatens the security of the local drinking water supply in North China. The results indicated that the PJKR showed obvious thermal and dissolved oxygen (DO) stratification in the warm seasons and full mixing in the cold seasons. The mean DO concentration was 9.9 and 3.55 mg/L in the epilimnion and hypolimnion, respectively, in warm seasons and 10.7 mg/L in cold seasons. The sediment acted as a source of soluble reactive phosphorus (SRP), NH4+-N, and NO2--N and a sink of NO3--N. The SRP fluxes were 5.28 ± 4.34 and 2.30 ± 1.93 mg m-2·d-1 in warm and cold seasons, respectively, and the dissolved inorganic nitrogen (DIN) fluxes were -0.66 ± 47.84 and 44.04 ± 84.05 mg m-2·d-1. Seasonal hypoxia accelerated the release of P rather than N from the sediments in warm seasons, which came mainly from Fe-P and Org-P under anoxic conditions. The strong negative NO3--N flux (diffusion from the water column to the sediment) implied an intensive denitrification process at the SWI, which can counteract the release flux of NH4+-N and NO2--N, resulting in the sediment acting as a weak dissolved inorganic nitrogen (DIN) source for the overlying water. We also found that internal N loading accounted for only ∼9% of the total N loading, while internal P loading accounted for 43% of the total P loading of the reservoir. Our results highlight that efforts to manage the internal loading of deep-water ecosystems should focus on P and seasonal hypoxia.


Assuntos
Fósforo , Poluentes Químicos da Água , China , Ecossistema , Monitoramento Ambiental/métodos , Eutrofização , Sedimentos Geológicos/análise , Humanos , Hipóxia , Lagos , Nitrogênio/análise , Dióxido de Nitrogênio/análise , Fósforo/análise , Água/análise , Poluentes Químicos da Água/análise
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