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1.
BMC Infect Dis ; 23(1): 606, 2023 Sep 16.
Artículo en Inglés | MEDLINE | ID: mdl-37716953

RESUMEN

BACKGROUND: Omicron variant of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has rapidly become a global threat to public health. Numerous asymptomatic and mild cases had been admitted in shelter hospitals to quickly win the fight against Omicron pandemic in Shanghai. However, little is known about influencing factors for deterioration and length of stay (LOS) in hospitals among these non-severe cases. METHODS: This study included 12,555 non-severe cases with COVID-19 in largest shelter hospital of Shanghai, aiming to explore prognostic factors and build effective models for prediction of LOS. RESULTS: Data showed that 75.0% of participants were initially asymptomatic. In addition, 94.6% were discharged within 10 days, only 0.3% with deterioration in hospitals. The multivariate analysis indicated that less comorbidities (OR = 1.792, P = 0.012) and booster vaccination (OR = 0.255, P = 0.015) was associated with the decreased risk of deterioration. Moreover, age (HR = 0.991, P < 0.001), number of symptoms (HR = 0.969, P = 0.005), time from diagnosis to admission (HR = 1.013, P = 0.001) and Cycle threshold (CT) values of N gene (HR = 1.081, P < 0.001) were significant factors associated with LOS. Based on these factors, a concise nomogram model for predicting patients discharged within 3 days or more than 10 days was built in the development cohort. In validation cohort, 0.75 and 0.73 of Areas under the curve (AUC) in nomograms, similar with AUC in models of simple machine learning, showed good performance in estimating LOS. CONCLUSION: Collectively, this study not only provides important evidence to deeply understand clinical characteristics and risk factors of short-term prognosis in Shanghai Omicron outbreaks, but also offers a concise and effective nomogram model to predict LOS. Our findings will play critical roles in screening high-risk groups, providing advice on duration of quarantine and helping decision-makers with better preparation in outbreak of COVID-19.


Asunto(s)
COVID-19 , Nomogramas , Humanos , Pronóstico , SARS-CoV-2 , China/epidemiología
2.
BMC Cancer ; 21(1): 132, 2021 Feb 06.
Artículo en Inglés | MEDLINE | ID: mdl-33549061

RESUMEN

BACKGROUND: Vascular mimicry (VM) was associated with the prognosis of cancers. The aim of the study was to explore the association between VM and anticancer therapy response in patients with lung adenocarcinoma. METHODS: This was a single-center retrospective study of patients with lung adenocarcinoma between March 1st, 2013, to April 1st, 2019, at the Second People's Hospital of Taizhou City. All included patients were divided into the VM and no-VM groups according to whether VM was observed or not in the specimen. Vessels with positive PAS and negative CD34 staining were confirmed as VM. The main outcome was progression-free survival (PFS). RESULTS: Sixty-six (50.4%) patients were male. Eighty-one patients received chemotherapy as the first-line treatment, and 50 patients received TKIs. Forty-five (34.4%) patients were confirmed with VM. There was no difference regarding the first-line treatment between the VM and no-VM groups (P = 0.285). The 86 patients without VM had a median PFS of 279 (range, 90-1095) days, and 45 patients with VM had a median PFS of 167 (range, 90-369) days (P < 0.001). T stage (hazard ratio (HR) = 1.37, 95% confidence interval (CI): 1.10-1.71), N stage (HR = 1.43, 95%CI: 1.09-1.86), M stage (HR = 2.85, 95%CI: 1.76-4.61), differentiation (HR = 1.85, 95%CI: 1.29-2.65), therapy (HR = 0.32, 95%CI: 0.21-0.49), VM (HR = 2.12, 95%CI: 1.33-3.37), and ECOG (HR = 1.41, 95%CI: 1.09-1.84) were independently associated with PFS. CONCLUSION: The benefits of first-line TKIs for NSCLC with EGFR mutation are possibly better than those of platinum-based regimens in patients without VM, but there is no difference in the benefit of chemotherapy or target therapy for VM-positive NSCLC harboring EGFR mutations.


Asunto(s)
Adenocarcinoma del Pulmón/tratamiento farmacológico , Receptores ErbB/genética , Neoplasias Pulmonares/tratamiento farmacológico , Mutación , Adenocarcinoma del Pulmón/irrigación sanguínea , Adenocarcinoma del Pulmón/genética , Adulto , Anciano , Anciano de 80 o más Años , Antígenos CD34/análisis , Femenino , Humanos , Neoplasias Pulmonares/irrigación sanguínea , Neoplasias Pulmonares/genética , Masculino , Persona de Mediana Edad , Compuestos de Platino/uso terapéutico , Pronóstico , Supervivencia sin Progresión , Inhibidores de Proteínas Quinasas/uso terapéutico , Proteínas Tirosina Quinasas/antagonistas & inhibidores , Estudios Retrospectivos
3.
Mikrochim Acta ; 187(8): 424, 2020 07 03.
Artículo en Inglés | MEDLINE | ID: mdl-32621131

RESUMEN

CoMoO4 materials were prepared through a simple hydrothermal method and developed as highly efficient peroxidase mimics for colorimetric determination of H2O2. Based on the different experimental conditions in the synthesis process, the CoMoO4 materials present distinct morphologies, structures, surface properties, and peroxidase mimetic activities. Among them, CoMoO4 nanobelts (NBs) display the best intrinsic peroxidase mimetic abilities due to the high-energy (100) facet exposed, more Co active sites at (100) facet, more negative potential, and larger specific surface area. It can efficiently catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of H2O2 to generate a blue oxide. In view of the excellent peroxidase mimetic catalytic activity of CoMoO4 NBs, a rapid, convenient, and ultrasensitive method was successfully established for the visual and colorimetric determination of H2O2. The method exhibits good selectivity, practicability, stability, and reusability, and has a detection limit of 0.27 µM. The peroxidase mimetic catalytic mechanism of CoMoO4 NBs was illustrated according to the kinetic and active species trapping experiments. The method has a good potential for rapid and sensitive determination of H2O2 for biomedical analysis. Graphical abstract Schematic presentation of the process of CoMoO4 nanobelts catalyzing the oxidation of peroxidase substrate 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of H2O2 to generate a typical blue color, which can be applied in rapid and ultrasensitive detection of H2O2 visually.


Asunto(s)
Colorimetría/métodos , Peróxido de Hidrógeno/análisis , Nanoestructuras/química , Bencidinas/química , Catálisis , Compuestos Cromogénicos/química , Cobalto/química , Peróxido de Hidrógeno/química , Límite de Detección , Molibdeno/química , Oxidación-Reducción , Óxidos/química
4.
Soft Matter ; 14(35): 7145-7154, 2018 Sep 11.
Artículo en Inglés | MEDLINE | ID: mdl-29978875

RESUMEN

Lipids are fundamental components of cells in organisms. Recent studies reveal that lipids are also present in cell-free bioadhesives. Examples include barnacle cement, sea star footprints, hairy and smooth pads of insects and gecko setae. Whether reliance on lipids is universal in bioadhesion is not known. In the present study, we demonstrated, for the first time, the involvement of lipids in mussel adhesion. We extracted, identified and localized lipids in the byssal threads. The lipids were confirmed as fatty acids by gas chromatograpy mass spectrometry. δ13C measurements of the fatty acids in the byssus were also conducted. Results show that byssal fatty acids, with concentrations ranging from 1.10-2.51 mg g-1 by thread dry weight depending on the mussel species, are localized both on the surface of and inside the byssal thread and plaque. Over half of the fatty acids were loosely attached to the surface while a small portion were tightly bound to the byssus. Most of the surface fatty acids disappear within a week of thread deposition. δ13C values of byssal fatty acids show isotope fractionation suggesting that thread fatty acids are derived from the foot. It is possible that fatty acids are key players in expelling water and preparing the substrate surface for adhesion. Using lipids in the adhesion process might be a common strategy for organisms in need of temporary or permanent attachment. The process of lipid participation may be as important as adhesive components for developing more efficient man-made glues.


Asunto(s)
Bivalvos/química , Bivalvos/metabolismo , Metabolismo de los Lípidos , Adhesividad , Animales , Biomimética , Ácidos Grasos/análisis , Lípidos/química
5.
J Sci Food Agric ; 95(8): 1655-61, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25131383

RESUMEN

BACKGROUND: Diacetyl (2,3-butanedione) is a common flavor aroma from fermented dairy products. There is a need to screen new microorganisms that can efficiently produce large amounts of diacetyl. RESULTS: A new lactic acid bacterium that produced high concentrations of diacetyl was identified based on Gram staining, microscopic examination and 16S rDNA sequence analysis as Lactococcus lactis DX. Its α-acetolactate decarboxylase (ALDC) was purified using 0.45 g mL(-1) ammonium sulfate precipitation, Sephacryl S-300 and S-200 HR and native-PAGE. The purified ALDC displayed a monomer structure and had a molecular mass of about 73.1 kDa, which was estimated using SDS-PAGE. IR analysis showed that the ALDC had a typical protein structure. The optimal temperature and pH for ALDC activity were 40 °C and 6.5 respectively. The ALDC of L. lactis DX was activated by Fe(2+) , Zn(2+) , Mg(2+) , Ba(2+) and Ca(2+) , while Cu(2+) significantly inhibited ALDC activity. Leucine, valine and isoleucine activated the ALDC. CONCLUSION: A strain that had high ability to produce diacetyl was identified as L. lactis DX. The difference in diacetyl production may be due to the ALDC, which is different from other ALDCs.


Asunto(s)
Carboxiliasas/aislamiento & purificación , Lactococcus lactis/enzimología , Carboxiliasas/química , Carboxiliasas/metabolismo , ADN Bacteriano/análisis , Diacetil/metabolismo , Electroforesis en Gel de Poliacrilamida , Activación Enzimática/efectos de los fármacos , Concentración de Iones de Hidrógeno , Lactococcus lactis/clasificación , Lactococcus lactis/genética , Estructura Molecular , Peso Molecular , Filogenia , ARN Ribosómico 16S/genética , Espectrofotometría Infrarroja , Temperatura
6.
Otol Neurotol ; 43(7): e780-e786, 2022 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-35763493

RESUMEN

OBJECTIVE: Benign paroxysmal positional vertigo (BPPV) is the most frequently diagnosed type of peripheral vestibular vertigo. Studies have reported a possible association between BPPV and osteoporosis; however, there is still a lack of evidence. This study aimed to investigate the characteristics of bone mineral density (BMD) and bithermal caloric test results in patients with unilateral posterior canal idiopathic benign paroxysmal positional vertigo (pc-iBPPV). METHODS: BMD was measured in 65pc-iBPPV menopausal female patients and 65 healthy controls using dual-energy xray absorptiometry and then compared the T-score of BMD between the two groups. The bithermal caloric test was also performed with video nystagmography and the relationship between canal paresis, directional preponderance, T-score, and recurrence were analyzed. RESULTS: Lower T-scores were observed in pc-iBPPV patients compared with the normal subjects. Among 65 pc-iBPPV patients, free recurrence was observed in 38 (58.5%), single recurrence was noted in 14 (21.5%), and multiple recurrences were seen in 13 (20%) patients. The proportion of positive T-score and CP value increased with the pc-BPPV recurrence frequency. Statistically, a significant difference was found only in T-score, indicating that recurrence was raised with a decrement of T-score. The proportion of positive CP values tended to increase as BMD decreased. CONCLUSION: The decrement of BMD might be one of the pathogeneses in patients with unilateral pc-iBPPV and associated with multiple recurrences. Moreover, positive CP value cannot be regarded as a predictive factor for recurrence; however, there is a clear association between CP and BMD.


Asunto(s)
Vértigo Posicional Paroxístico Benigno , Osteoporosis , Absorciometría de Fotón , Vértigo Posicional Paroxístico Benigno/diagnóstico , Densidad Ósea , Pruebas Calóricas , Femenino , Humanos , Osteoporosis/diagnóstico por imagen , Canales Semicirculares
7.
Sci Total Environ ; 818: 151819, 2022 Apr 20.
Artículo en Inglés | MEDLINE | ID: mdl-34838564

RESUMEN

In this study, components, concentrations, distribution characteristics, sources of low-molecular-weight organic acids (LMWOAs) and relationships among the annual hypoxia, LMWOAs and seawater acidification were investigated in the Changjiang Estuary and its adjacent sea area in July 2015. Lactic, acetic and formic acids were detected in the seawater samples in the study area, and their total concentrations (ΣLMWOAs) varied from 0 to 262.6 µmol·L-1, with an average value of 39.2 µmol·L-1. In the surface seawater, high concentration areas of ΣLMWOAs occurred in the sea area near the Changjiang Estuary and the Hangzhou Bay, and north of study area. In the sampling stations along transect A6, high concentration areas of ΣLMWOAs appeared in the bottom seawater of nearshore stations and middle seawater of offshore stations. The terrigenous inputs, especially the Changjiang runoff, were the dominant sources for LMWOAs in the sampling period. The consistency of hypoxia areas, high concentration areas of ΣLMWOAs and low pH value areas in winter and summer suggested that annual hypoxia could cause the long-term seawater acidification by producing LMWOAs in the Changjiang Estuary and its adjacent sea area.


Asunto(s)
Monitoreo del Ambiente , Estuarios , China , Humanos , Concentración de Iones de Hidrógeno , Hipoxia , Agua de Mar
8.
J Thorac Dis ; 12(12): 7337-7345, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-33447423

RESUMEN

BACKGROUND: Esophageal cancer (EC) with a high incidence of malnutrition is a highly malignant digestive tract tumor. We investigated the effect of enteral nutrition (EN) support combined with enhanced recovery after surgery (ERAS) on the nutritional status, immune function, and prognosis of patients with EC after Ivor-Lewis operation. METHODS: One hundred patients were randomly divided into the observation group (n=42) and the control group (n=58). The patients in observation group were treated with EN combined with ERAS intervention after Ivor-Lewis operation, and the patients in control group were treated with conventional postoperative EN intervention. The situation of operation, nutritional status, immune function recovery and prognosis between the two groups were compared. RESULTS: There was no statistically significant difference in operation time or intraoperative blood loss between the two groups (P>0.05). The chest tube removal time and oral feeding time of the observation group after operation were shorter than those of the control group (P<0.05). After intervention, serum albumin (ALB), transferrin (TF), pre-albumin (PA) and hemoglobin (Hb) levels in both groups were significantly decreased. These indexes were significantly higher in the observation group than in the control group (P<0.05). There were no significant changes in the levels of immunoglobulin (Ig) A, IgG, and IgM, or the numbers of CD3+, CD4+ and CD4+/CD8+ T cells in the observation group before and after intervention (P>0.05); however those indexes were significantly decreased in the control group after the intervention (P<0.05). Interestingly, the levels of IgA, IgM, IgG, CD3+ T cells, CD4+ T cells and CD4+/CD8+ T cells in the observation group were significantly higher than those in the control group after intervention (P<0.05). The incidence of pulmonary infection in the observation group was significantly lower than that in the control group. The postoperative exhaust time, postoperative defecation time and postoperative hospital stay were shorter in the observation group than in the control group (P<0.05). There was no significant difference in hospitalization cost between the two groups (P>0.05). CONCLUSIONS: EN combined with ERAS was more beneficial to the improvement of nutritional status and immune function recovery of patients with EC after Ivor-Lewis operation. It also shortened the length of hospital stay.

9.
Mar Pollut Bull ; 161(Pt B): 111741, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-33217637

RESUMEN

In this study, components, concentrations, distribution characteristics and sources of low molecular weight organic acids (LMWOAs) in seawater of the Changjiang Estuary and its adjacent East China Sea were investigated in March 2015. Lactic, acetic and formic acids were identified with their concentration range of 0-16.7, 0-42.7 and 0-6.7 µmol·L-1, respectively. In the surface seawater, high concentrations of LMWOAs appeared in the sea area close to the estuary and along the coast. LMWOAs were important fractions of dissolved organic carbon and acetic acid was dominant component of LMWOAs. Riverine, terrestrial input, phytoplankton and sediment release were important sources for the LMWOAs, and human activities were considered as dominant sources for them in sampling period. The consistency of regions with high concentrations of LMWOAs, eutrophication, seasonal hypoxia and frequent red tide occurrence suggested LMWOAs as potential indicators for evaluating pollution status in coastal areas.


Asunto(s)
Estuarios , Agua de Mar , China , Monitoreo del Ambiente , Peso Molecular , Fitoplancton
10.
Sci Total Environ ; 727: 138458, 2020 Jul 20.
Artículo en Inglés | MEDLINE | ID: mdl-32339827

RESUMEN

Low-molecular-weight organic acids (LMWOAs) are ubiquitous water-soluble organic compounds with mass production worldwide, but their influence on coastal marine environments is still lack of consideration. In this study, we select a typical nearshore bay - the Jiaozhou Bay, which is surrounded by Qingdao - a city with modern manufacture, agriculture, aquaculture and service industry, as study area, to investigate the effect of LMWOAs on the nearshore marine environment, and their impact on seawater acidification in coastal areas. During Sep. 2016 to Aug. 2017, we identified three different LMWOAs - acetic acid (AA), formic acid (FA) and lactic acid (LA), with average concentrations of 46.7, 13.9 and 1.4 µmol·L-1 in the seawater of the bay, respectively. Due to the establishment of the Jiaozhou Bay Bridge, the seawater exchange capacity was weakened and thereby the concentration and stocks of AA and FA increased. As weak acids in seawater, the influence of LMWOAs on the seawater acidification of the Jiaozhou Bay was investigated. LMWOAs had significant impact on seawater pH and every 10 µmol·L-1 LMWOA caused an average of 0.02 pH unit decrease. From 2010 to 2017, pH value in the seawater of the bay decreased by about 0.103 and LMWOAs contributed about 83% of its decrease. Besides, two models were established to estimate the influence of LMWOAs on the seawater pH by applying the data set of dissolved inorganic carbon (DIC), total alkalinity (TA) and LMWOAs. The results showed that LMWOAs could enhance acidification of coastal seawater. Considering the importance of LMWOAs in seawater, it is necessary to evaluate their future changes in coastal marine environments. This study initiated a way to identify the source of LMWOAs in seawater and to evaluate their contribution to seawater acidification, and also provided a series of dataset for future study on LMWOAs in coastal environment.

11.
Mar Pollut Bull ; 152: 110885, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-32479275

RESUMEN

Microplastics are ubiquitous in our environment, yet we have little knowledge on their accumulation profile and changing trend. In this study, we selected the semi-enclosed Jiaozhou Bay as the research area to study the vertical distribution characteristics of microplastic in the sediment and analyzed factors that might affect this distribution pattern. We found six different polymer types and the microplastic abundance ranged between 2.5 items/kg d.w.-27.5 items/kg d.w.. Microplastic abundance was very low in deep sediment and generally showed a decreasing trend from the surface down with some shifts at different depth at certain sites. Based on our data, the total microplastics in the sediment were estimated to reach 3.71 tons in Jiaozhou Bay. This study shows that the vertical microplastic abundance profile in the sediment can not only show the microplastics pollution level but also reflect environmental factors and anthropogenic impacts.


Asunto(s)
Plásticos , Contaminantes Químicos del Agua/análisis , Bahías , Monitoreo del Ambiente , Microplásticos
12.
Front Microbiol ; 8: 186, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28289403

RESUMEN

The marine subsurface is a reservoir of the greenhouse gas methane. While microorganisms living in water column and seafloor ecosystems are known to be a major sink limiting net methane transport from the marine subsurface to the atmosphere, few studies have assessed the flow of methane-derived carbon through the benthic mat communities that line the seafloor on the continental shelf where methane is emitted. We analyzed the abundance and isotope composition of fatty acids in microbial mats grown in the shallow Coal Oil Point seep field off Santa Barbara, CA, USA, where seep gas is a mixture of methane and CO2. We further used stable isotope probing (SIP) to track methane incorporation into mat biomass. We found evidence that multiple allochthonous substrates supported the rich growth of these mats, with notable contributions from bacterial methanotrophs and sulfur-oxidizers as well as eukaryotic phototrophs. Fatty acids characteristic of methanotrophs were shown to be abundant and 13C-enriched in SIP samples, and DNA-SIP identified members of the methanotrophic family Methylococcaceae as major 13CH4 consumers. Members of Sulfuricurvaceae, Sulfurospirillaceae, and Sulfurovumaceae are implicated in fixation of seep CO2. The mats' autotrophs support a diverse assemblage of co-occurring bacteria and protozoa, with Methylophaga as key consumers of methane-derived organic matter. This study identifies the taxa contributing to the flow of seep-derived carbon through microbial mat biomass, revealing the bacterial and eukaryotic diversity of these remarkable ecosystems.

13.
Cell Biochem Biophys ; 71(1): 465-72, 2015 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-25182004

RESUMEN

Breast cancer metastasis suppressor 1 (BRMS1) was originally identified as a metastasis suppressor gene in human breast cancer. Previous studies have reported that loss of BRMS1 expression correlates with tumor progression, and poor prognosis in NSCLC. However, the role of BRMS1 in NSCLC is not fully understood. In this study, we found that expression of BRMS1 in A549 cells did not affect cell growth under normal culture conditions but sensitized cells to apoptosis induced by serum deprivation. Consistently, knockdown of endogenous BRMS1 expression in H1299 cells suppressed cell apoptosis. We identified that BRMS1 regulate apoptosis in NSCLC cells by modulating Stat3 activation. Taken together, our results show that BRMS1 sensitizes NSCLC cells to apoptosis through Stat3 signaling pathway, suggesting a potential role of BRMS1 in regulating NSCLC apoptosis and metastasis.


Asunto(s)
Apoptosis , Carcinoma de Pulmón de Células no Pequeñas/patología , Neoplasias Pulmonares/patología , Proteínas Represoras/metabolismo , Apoptosis/genética , Línea Celular Tumoral , Proliferación Celular/genética , Regulación Neoplásica de la Expresión Génica , Técnicas de Silenciamiento del Gen , Humanos , Interleucina-6/metabolismo , Metástasis de la Neoplasia , Proteínas Represoras/deficiencia , Proteínas Represoras/genética , Factor de Transcripción STAT3/metabolismo , Transducción de Señal/genética
14.
Appl Biochem Biotechnol ; 171(5): 1203-11, 2013 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-23553103

RESUMEN

The structure, organic matrix, and mineral structure of the scar (the interface between the adductor muscle and the shell) in Mytilus galloprovincialis were investigated. The scar was found to be a hierarchically multilayered structure composed of organic matrix and structurally different minerals. Different from the aragonite structure of the nacre, we have identified the top layer of the scar to contain structurally organized columnar calcite. This is the first report on calcite-containing scar. Study of the organic matrix showed that there was at least one protein that seemed to be preferentially localized in this columnar layer. Since the scar is the most important stress distribution site in the mussel, the function of the columnar structure and the matrix protein was discussed in relation to a similar structure at the tendon-bone connection site.


Asunto(s)
Exoesqueleto/química , Músculos/química , Mytilus/química , Exoesqueleto/anatomía & histología , Exoesqueleto/ultraestructura , Animales , Microscopía Electroquímica de Rastreo , Músculos/anatomía & histología , Mytilus/anatomía & histología , Mytilus/ultraestructura , Transporte de Proteínas , Proteínas/análisis
15.
Huan Jing Ke Xue ; 34(11): 4231-9, 2013 Nov.
Artículo en Zh | MEDLINE | ID: mdl-24455929

RESUMEN

Series of laboratory incubation experiments were conducted to simulate degradation of organic matter in sediment-seawater interface in hypoxia enviroments along China coastal area. Under four different redox conditions (oxygen saturation: 100%, 50%, 25% and 0%), degradations of seveal biomarkers originated from Skeletonema costatum, a typical red tide alage along China coastal area were tracked. By analyzing concentrations of four fatty acid biomarkers [14:0, 16:0, 16:1(7) and 20:5] obtained at various sampling time, results showed that their concentrations decreased significantly after 2-3 weeks' incubation. Then, their concentrations changed very slowly or very little. However, degradation of the four fatty acids varied dramatically in different incubation systems. Fatty acids 14:0, 16:1(7) and 20:5 were degraded completely in all incubation systems after two-month incubation, but 25% to 35% of 16:0 was reserved in the systems. Based on multi-G model, degradations of the four fatty acids were quantively described. The results indicated that all four fatty acids had fast-degraded and slow-degraded fractions. Their degradation rate constants (k(av)) ranged from 0.079 to 0.84 d(-1). The fastest degradation of 14:0 and 16:1 (7) occurred under 25% oxygen concentrations. For these two compounds, in the fastest degradation system, their k(av), values were 2.3 folds and 1.7 folds higher than those in the slowest degradation system [50% oxygen saturation for 14:0 and 100% oxygen saturation for 16:1(7)] respectively. The 16:0 was degraded fastest under the anoxic condition and slowest under the 50% oxygen saturation. The ratio of the two k(av)s was 2.1. The k(av)s of 20:5 had a positive relationship with oxygen saturations. Results of this study suggested that besides oxgen saturations, structure and features of organic compounds, roles of microbe in the envrioments and etc. might affect degradations of fatty acids in S. costatum in hypoxia sediment-seawater interface along China coastal area.


Asunto(s)
Diatomeas/química , Ácidos Grasos/química , Sedimentos Geológicos/análisis , Agua de Mar/análisis , China , Floraciones de Algas Nocivas , Modelos Teóricos , Compuestos Orgánicos/química , Oxígeno
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