RESUMO
The naturally persistent flow of hundreds of dust particles is experimentally achieved in a dusty plasma system with the asymmetric sawteeth of gears on the electrode. It is also demonstrated that the direction of the dust particle flow can be controlled by changing the plasma conditions of the gas pressure or the plasma power. Numerical simulations of dust particles with the ion drag inside the asymmetric sawteeth verify the experimental observations of the flow rectification of dust particles. Both experiments and simulations suggest that the asymmetric potential and the collective effect are the two keys in this dusty plasma ratchet. With the nonequilibrium ion drag, the dust flow along the asymmetric orientation of this electric potential of the ratchet can be reversed by changing the balance height of dust particles using different plasma conditions.
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Soil samples from 16 urban sites in Lianyungang, China were collected and analyzed. A pollution index was used to assess the potential ecological risk of heavy metals and a sequential extraction procedure was used to evaluate the relative distribution of Cu, Zn, Pb, Cd, Cr, and As in exchangeable, carbonate, Fe/Mn oxide, organic/sulfide, and residual fractions. The mobility of heavy metals and urease (URE) activity, alkaline phosphatase (ALP) activity, and invertase (INV) activity of soils was determined. The results showed that the average concentrations of Cu, Zn, Pb, Cd, Cr, and As in Lianyungang soils were much higher than those in the coastal city soil background values of Jiangsu and China. Among the five studied regions (utilities, commercial, industrial, tourism, and roadside), the industrial region had the highest metal concentrations demonstrating that land use had a significant impact on the accumulation of heavy metals in Lianyungang soils. Compared to the other metals, Cd showed the highest ecological risk. According to chemical partitioning, Cu was associated with the organic/sulfides and Pb and Zn were mainly in the carbonate and the Fe/Mn oxide phase. The greatest amounts of Cd were found in exchangeable and carbonate fractions, while Cr and As were mainly in the residual fraction. Cd had the highest mobility of all metals, and the order of mobility (highest to lowest) of heavy metals in Lianyungang soils was Cd > Zn > Pb > Cu > As > Cr. Soil urease activity, alkaline phosphatase activity, and invertase activity varied considerably in different pollution degree sites. Soil enzyme activities had the lowest levels in roadside and industrial regions. Across all the soil data in the five regions, the total Cu, Zn, Pb, Cd, Cr, and As level was negatively correlated with urease activity, alkaline phosphatase activity, and invertase activity, but the relationship was not significant. In the industrial region, alkaline phosphatase activity had significant negative correlations with total Cu, Pb, Cr, Zn, Cd, and heavy metal fractions. This showed that alkaline phosphatase activity was sensitive to heavy metals in heavily contaminated regions, whereas urease and invertase were less affected. The combination of the various methods may offer a powerful analytical technique in the study of heavy metal pollution in street soil.
Assuntos
Monitoramento Ambiental , Metais Pesados/análise , Poluentes do Solo/análise , Solo/química , China , Cidades , Resíduos Industriais/análiseRESUMO
BACKGROUND: In the early stage of diabetes, the cardiac ejection fraction is preserved, despite the existence of the subclinical cardiac dysfunction to some extent. However, the detailed phenotype of this dysfunction and the underlying mechanism remain unclear. To improve our understanding of this issue, we used low-dose STZ and high-fat diet to induce type 2 diabetic models in rats. The effects and the mechanism associated with the early stages of the disease were analyzed. METHODS: The type 2 diabetic mellitus (T2DM) in SD rats were induced through 30 mg/kg STZ and high-fat diet. Two-dimensional spackle-tracking echocardiography (STE) and the dobutamine test were performed to examine the cardiac function. Calcium transients of left ventricular myocytes were detected and the related intracellular signalling factors were analyzed by western blotting. RESULTS: After 6-weeks, T2DM rats in left ventricular (LV) diastole showed decreased global and segment strain(S) levels (P < 0.05), both in the radial and circumferential directions. Strain rate (Sr) abatement occurred in three segments in the radial and circumferential directions (P < 0.05), and the radial global Sr also decreased (P < 0.05). In the systolic LV, radial Sr was reduced, except the segment of the anterior septum, and the Sr of the lateral wall and post septum decreased in the circumferential direction (P < 0.05). Conventional M-mode echocardiography failed to detect significant alterations of cardiac performance between the two groups even after 12 weeks, and the decreased ejection fraction (EF%), fractional shortening (FS%) and end-systolic diameters (ESD) could be detected only under stress conditions induced by dobutamine (P < 0.05). In terms of calcium transients in cardiac myocytes, the Tpeak in model rats at 6 weeks was not affected, while the Tdecay1/2 was higher than that of the controls (P < 0.05), and both showed a dose-dependent delay after isoproterenol treatment (P < 0.05). Western blot analysis showed that in 6-week T2DM rats, myocardial p-PLB expression was elevated, whereas p-CaMKII, p-AMPK and Sirt1 were significantly down-regulated (P < 0.05). CONCLUSION: A rat model of T2DM was established by low dose STZ and a high-fat diet. LV deformation was observed in the early stages of T2DM in association with the delay of Ca(2+) transients in cardiomyocytes due to the decreased phosphorylation of CaMKII. Myocardial metabolism remodeling might contribute to the early LV function and calcium transportation abnormalities.
Assuntos
Cálcio/metabolismo , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Cardiomiopatias Diabéticas/metabolismo , Dieta Hiperlipídica , Ventrículos do Coração/metabolismo , Miócitos Cardíacos/metabolismo , Proteínas Quinases Ativadas por AMP/metabolismo , Animais , Western Blotting , Proteínas de Ligação ao Cálcio/metabolismo , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Diabetes Mellitus Experimental/complicações , Diabetes Mellitus Tipo 2/complicações , Cardiomiopatias Diabéticas/diagnóstico por imagem , Cardiomiopatias Diabéticas/etiologia , Modelos Animais de Doenças , Ecocardiografia , Ecocardiografia sob Estresse , Eletroforese em Gel de Poliacrilamida , Ventrículos do Coração/citologia , Ventrículos do Coração/diagnóstico por imagem , Immunoblotting , Fosfoproteínas/metabolismo , Ratos , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/metabolismo , Sirtuína 1/metabolismoRESUMO
OBJECTIVE: To evaluate the difference of plasma lactate level between dipping and non-dipping hypertension, and to investigate the effects of lactate on subclinical cardiovascular damages in dipping and non-dipping hypertension. METHODS: According to 24 h ambulatory blood pressure monitoring, 236 patients with dipping and 152 with non-dipping hypertension were included. Clinical characteristics were collected and compared between dipping and non-dipping groups. Left ventricle hypertrophy (LVH) and N-terminal pro-B type natriuretic peptide (NT-proBNP) level were used to evaluate subclinical cardiovascular damage. Multivariate regression analysis was performed to evaluate the relationship between lactate and LVH and NT-proBNP elevation. RESULTS: Compared to dipping hypertension, plasma levels of lactate and NT-proBNP in non-dipping hypertension group were significantly higher. Moreover, the value of left ventricle mass index to height (LVMI/height) was also significantly higher in non-dipping group, and the percentage of patient with LVH was also higher in non-dipping group (36.8% vs. 28.9%, P < 0.05). Multivariate regression analysis revealed that in non-dipping group, after fully adjustment, the associations between lactate with LVH and NT-proBNP remained significant, with odds ratio (OR) of 1.18 (95% confidence interval [CI] of 1.13-1.24) in LVH and OR of 1.16 in NT-proBNP (95% CI of 1.10-1.23), respectively. Nonetheless, the associations between lactate with LVH and NT-proBNP elevation in dipping group were diminished to statistical nonsignificance. CONCLUSION: Plasma lactate level in non-dipping hypertension is significantly higher than dipping hypertension, and this difference may be the potential mechanism non-dipping hypertension contributes to greater targeted organ damage.
Assuntos
Sistema Cardiovascular , Hipertensão , Hipertrofia Ventricular Esquerda , Ácido Láctico/sangue , Peptídeo Natriurético Encefálico/sangue , Fragmentos de Peptídeos/sangue , Adulto , Idoso , Doenças Assintomáticas , Monitorização Ambulatorial da Pressão Arterial/métodos , Sistema Cardiovascular/metabolismo , Sistema Cardiovascular/fisiopatologia , Feminino , Humanos , Hipertensão/sangue , Hipertensão/diagnóstico , Hipertensão/fisiopatologia , Hipertrofia Ventricular Esquerda/sangue , Hipertrofia Ventricular Esquerda/diagnóstico , Hipertrofia Ventricular Esquerda/fisiopatologia , Masculino , Pessoa de Meia-Idade , Estatística como AssuntoRESUMO
Surface sediments were collected at 31 sites covering five functional zones of Haizhou Bay, Lianyungang, Jiangsu, China. Heavy metal concentrations and enzymatic activity of phosphatase and urease were determined on a dry-weight basis of sediments. Metal concentrations in sediments were comparable to the Chinese National Standard of Marine Sediment Quality and were as follows: Cu, 8.60-55.8 mg kg(-1); Zn, 107-384 mg kg(-1); Pb, 33.6-200 mg kg(-1); Cd, 0.24-2.57 mg kg(-1); Cr, 30.3-92.1 mg kg(-1); As, 12.9-110 mg kg(-1); Ni, 15.8-49.6 mg kg(-1); Mn, 379-1272 mg kg(-1); and Fe, 13,790-38,240 mg kg(-1). A geoaccumulation index (I geo) was calculated to help researchers understand the status of pollutants in the sediments. I geo showed that Cd and As contamination existed in the study area. The mobility of the metals and the relationship between heavy metal concentrations of chemical fractions and enzymatic activities were also investigated. Results showed that Cd and Mn had higher mobility than other metals, and enzymatic activities may play an important role in controlling the bioavailability and transformation trend of heavy metals from one fraction to another in sediments.
Assuntos
Monitoramento Ambiental , Sedimentos Geológicos/química , Metais Pesados/análise , Poluentes Químicos da Água/análise , Baías , ChinaRESUMO
BACKGROUND: During laparoscopic resection for colorectal cancer, there is controversy regarding whether the left colic artery (LCA) should be preserved at its origin. AIM: To investigate the prognostic significance of preservation of the LCA in colorectal cancer surgery. METHODS: Patients were divided into two groups. The high ligation (H-L) technique (refers to ligation performed 1 cm from the beginning of the inferior mesenteric artery) group consisted of 46 patients, and the low ligation (L-L) technique (refers to ligation performed below the initiation of the LCA) group consisted of 148 patients. Operative time, blood loss, lymph nodes with tumor invasion, postoperative complications and recovery time, recurrence rate, and 5-year survival rate were compared between the two groups. RESULTS: The average number of lymph nodes detected in postoperative pathological specimens was 17.4/person in the H-L group and 15.9/person in the L-L group. There were 20 patients (43%) with positive lymph nodes (lymph node metastasis) in the H-L group and 60 patients (41%) in the L-L group. No statistical differences were found between the groups. Complications occurred in 12 cases (26%) in the H-L group and in 26 cases (18%) in the L-L group. The incidences of postoperative anastomotic complications and functional urinary complications were significantly lower in the L-L group. The 5-year survival rates in H-L and L-L groups were 81.7% and 81.6%, respectively, and relapse-free survival rates were 74.3% and 77.1%, respectively. The two groups were similar statistically. CONCLUSION: Complete mesenteric resection combined with lymph node dissection around the inferior mesenteric artery root while preserving the LCA is a beneficial surgical approach during laparoscopic resection for colorectal cancer.
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OBJECTIVES: To assess the effectiveness and safety of additional bedtime H(2)-receptor antagonists (H(2)RAs) in suppressing nocturnal gastric acid breakthrough (NAB) via a systematic review. METHODS: Eligible trials were identified by searching the Cochrane Central Register of Controlled Trials (CENTRAL) (Cochrane Library Issue 2, 2004), MEDLINE (January 1966-June 2004), EMBASE (January 1980-June 2004) and CINAHL (January 1982-June 2004). Additional hand-searching was conducted on the proceedings of correlated conferences, eight important Chinese journals and references of all included trials. All randomized controlled trials evaluating H(2)RAs for the control of NAB were eligible for inclusion. The systematic review was conducted using methods recommended by The Cochrane Collaboration. RESULTS: Only two randomized crossover studies, comprising 32 participants, met the inclusion criteria. Because the design, dosage and duration of the treatments were different between the studies, it was not possible to conduct meta-analysis. There were no consistent conclusions found between the two included studies in evaluating H(2)RAs for the control of NAB. CONCLUSIONS: No implications for practice at this stage can be concluded. Appropriately designed large-scale randomized controlled trials with long-term follow up are needed to determine the effects of additional bedtime H(2)RAs in suppressing NAB.
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Ácido Gástrico/metabolismo , Antagonistas dos Receptores H2 da Histamina/administração & dosagem , Esquema de Medicação , Humanos , Omeprazol/administração & dosagem , Ensaios Clínicos Controlados Aleatórios como Assunto , Ranitidina/administração & dosagemRESUMO
OBJECTIVE: To study the relationship between cartilage end-plate calcification (CEC) and cervical intervertebral discs regression (CIDR) in rabbits, and to study the inhibitory effect of combined therapy of Kanggu Zengsheng Capsule (KZC) ansforming growth factor-apsule (TGF-PLC) and igene therapy (GT) on CEC by measuring the thickness of CEC layer. METHODS: Thirty-five New Zeland rabbits of 4 months old were selected to establish cervical dynamic imbalance rabbit model for inducing CIDR (No disposal was given to rabbits in the normal control group). Seven months after operation, combined therapy of KZC and PLC were given, in doses calculated by body weight, to the modeled rabbits in the drug treated group with CEC of either superficial layer or full layer, twice a dantly by gavage for 30 successive days. While to those in the gene therapy group, the recombinant plasmid DNA with transforming growth factor-beta1 (TGF-beta1) was injected once their intervertebral discs (ID) of C(2-3) C(3-4) and C(4-5), 20 microl for each injection. One month later, all rabbits were sacrificed with periotic venous gas embolic method and their ID of C(4-5) (including partial body of the upper and lower vertebrae) was resected. The degree of CIDR was evaluated morphologically, and the thickness of CEC in rabbits was measured and compared between groups. RESULTS: Thickness of CEC in the model group, either of superficial layer or of full layer, was significantly more than that in the normal control group with significant difference. Both combined KZC and PLC therapy and gene therapy showed significant inhibitory effects on CEC in treating CIDR (P < 0.05). CONCLUSION: CEC is the initial factor of CIDR with highly positive correlation. Both combined therapy of KZC and PLC and gene therapy can significantly inhibit CEC.
Assuntos
Calcinose/patologia , Cartilagem/patologia , Vértebras Cervicais/patologia , Disco Intervertebral/patologia , Fitoterapia , Doenças da Coluna Vertebral/terapia , Animais , Calcinose/complicações , Terapia Combinada , Medicamentos de Ervas Chinesas/uso terapêutico , Feminino , Terapia Genética , Masculino , Coelhos , Distribuição Aleatória , Doenças da Coluna Vertebral/complicações , Doenças da Coluna Vertebral/patologiaRESUMO
We study the interaction of both dense and sparse multiarmed spirals in bistable media modeled by equations of the FitzHugh-Nagumo type. A dense one-armed spiral is characterized by its fixed tip. For dense multiarmed spirals, when the initial distance between tips is less than a critical value, the arms collide, connect, and disconnect continuously as the spirals rotate. The continuous reconstruction between the front and the back drives the tips to corotate along a rough circle and to meander zigzaggedly. The rotation frequency of tip, the frequency of zigzagged displacement, the frequency of spiral, the oscillation frequency of media, and the number of arms satisfy certain relations as long as the control parameters of the model are fixed. When the initial distance between tips is larger than the critical value, the behaviors of individual arms within either dense or sparse multiarmed spirals are identical to that of corresponding one-armed spirals.
Assuntos
Modelos Teóricos , Dinâmica não Linear , Oscilometria/métodos , Simulação por ComputadorRESUMO
Coastal zone could be considered as an important sink of regional source to sink and preserve historical records of environmental evolution. Four sediment cores, collected from tidal flat at Haizhou Bay near Lianyungang City, were examined for concentrations of heavy metals including Cd, Cr, Cu, Mn, Pb and Zn in core sediments to investigate the historical input of trace metals. In addition, sediment rates of cores LH3 and LH4 were determined based on radionuclide 210Pb. The results showed that grain size control effect was not the main factor that influenced the distribution of heavy metals. Heavy metals concentrations in the surface sediments were higher than these regional background values. Furthermore, Al element as a proxy of grain size was selected for normalization and calculation of metal enrichment factor (EF) and anthropogenic heavy metal fluxes. The results revealed that heavy metals in tidal flats were continuously enriched in the past decades, meanwhile, tidal flats have been significantly subjected to contaminations due to anthropogenic activities. Moreover, the depth profiles of heavy metals fluxes correspond to scenario of social-economy development of Lianyungang, which is an important urban area near Haizhou Bay. From 1950s to 2005, anthropogenic fluxes of metals increased with fluctuations, whereas, since 2005 anthropogenic fluxes declined, which may be correlated to the adjustment of industrial structure as well as the strengthened environmental regulation.
Assuntos
Monitoramento Ambiental , Sedimentos Geológicos/química , Metais Pesados/análise , Poluentes Químicos da Água/análise , Poluição da Água/história , Baías , China , História do Século XX , História do Século XXI , Água do Mar/análise , Ondas de MaréRESUMO
Total phosphorus (TP), inorganic-phosphorus(IP), organic-phosphorus (OP), Fe/Al-bound phosphorus (NaOH-P) and Ca-bound phosphorus (HCl-P) in surface sediments of Chaohu Lake were measured, using the standard measurement and test (SMT) procedure of phosphorus forms in freshwater sediments. ArcGIS 9.2 and goestatistics software GS + 5. 3 were applied to process the spatial data and interpolation. Results showed that no significant seasonal variation of TN, TP and organic matter contents in sediments were presented, and the western lake had higher contents of TN, TP and organic matter than those in eastern lake; the C/N ratios varied from 21.35 to 28.19, with average value of 24.94, which demonstrated the dominance of non-point source pollution. The TP contents in surface sediments ranged from 528.90 to 1 385.71 mg x kg(-1), and the main form of TP in sediments was IP(accounted for 55.78% -79.86% of TP). The OP in sediments ranged from 169.05 mg x kg(-1) to 841.24 mg x kg(-1), with eastern lake and western lake were 376.02 mg x kg(-1) and 406.53 mg x kg(-1), respectively (accounted for 47.49% and 36.28% of TP); the NaOH-P contents in sediments ranged from 33.77 mg x kg(-1) to 411.37 mg x kg(-1), with eastern lake and western lake of 376.02 mg x kg(-1) and 406.53 mg x kg(-1), respectively (accounted for 21.73% and 33.12% of the IP); the HCl-P contents ranged from 194.95 mg x kg(-1) to 477.45 mg x kg(-1), with eastern lake and western lake 321.71 mg x kg(-1). and 338.08 mg x kg(-1), respectively (accounted for 64.50% and 40.53% of the IP), which was the main species of IP. The OP contents was high in spring and winter compared with summer and autumn, while the contents of HCl-P and NaOH-P in summer and autumn were higher than those in spring and winter.