2,617 research outputs found
Competing orders and inter-layer tunnelling in cuprate superconductors: A finite temperature Landau theory
We propose a finite temperature Landau theory that describes competing orders
and interlayer tunneling in cuprate superconductors as an important extension
to a corresponding theory at zero temperature [Nature {\bf 428}, 53 (2004)],
where the superconducting transition temperature is defined in three
possible ways as a function of the zero temperature order parameter. For given
parameters, our theory determines without any ambiguity. In mono- and
double-layer systems we discuss the relation between zero temperature order
parameter and the associated transition temperature in the presence of
competing orders, and draw a connection to the puzzling experimental fact that
the pseudo-gap temperature is much higher than the corresponding energy scale
near optimum doping. Applying the theory to multi-layer systems, we calculate
the layer-number dependence of . In a reasonable parameter space the
result turns out to be in agreement with experiments.Comment: 5 pages, 3 figure
3,6-Dihydroxy-2′-[(2-hydroxy-1-naphthyl)methyleneamino]xanthene-9-spiro-1′-isoindolin-3′-one acetonitrile solvate
The title compound, C31H20N2O5·C2H3N, was synthesized by the reaction of fluorescein hydrazide and excess 2-hydroxy-1-naphthaldehyde in acetonitrile. The spirolactam ring is planar and is nearly at right angles to the two benzene rings of the xanthene system. The dihedral angle between the two benzene rings of the xanthene system is 9.92 (4)°. In the crystal structure, the molecules are linked into extended two-dimensional networks by intermolecular hydrogen bonding. Acetonitrile molecules are located in the voids between the two-dimensional networks
Geochemical modeling of groundwater in southern plain area of Pengyang County, Ningxia, China
AbstractThe purpose of this paper is to examine the evolution mechanisms of a hydrochemical field and to promote its benefits to the living standards of local people and to the local economy in the southern plain area of Pengyang County, in Ningxia, China. Based on understanding of the hydrogeological conditions in Pengyang County, the chemical evolution characteristics of groundwater in the plain area were analyzed. PHREEQC geochemical modeling software was used to perform hydrochemical modeling of water-rock interaction and to quantitatively analyze the evolution processes and the formation mechanisms of the local groundwater. Geochemical modeling was performed for two groundwater paths. The results showed that, along path 1, Na+ adsorption played the leading role in the precipitation process and its amount was the largest, up to 6.08 mmol/L; cation exchange was significant along path 1, while along simulated path 2, albite accounted for the largest amount of dissolution, reaching 9.06 mmol/L, and the cation exchange was not significant. According to the modeling results, along the groundwater flow path, calcite and dolomite showed oversaturated status with a precipitation trend, while the fluorite and gypsum throughout the simulated path were not saturated and showed a dissolution trend. The total dissolved solids (TDS) increased and water quality worsened along the flow path. The dissolution reactions of albite, CO2, and halite, the exchange adsorption reaction of Na+, and the precipitation of sodium montmorillonite and calcite were the primary hydrogeochemical reactions, resulting in changes of hydrochemical ingredients
Identification of alternative splicing variants of the β subunit of human Ca2+/calmodulin-dependent protein kinase II with different activities
AbstractThe β subunit of human Ca2+/calmodulin-dependent protein kinase II (β CaMKII) was identified by searching through an expressed sequence tag database and rapid amplification of cDNA 5′-ends and was assigned to chromosome 7. Reverse transcription-polymerase chain reaction and sequencing analysis identified at least five alternative splicing variants of β CaMKII (β, β6, βe, β′e, and β7) in brain and two of them (β6 and β7) were first detected in any species. When expressed in HEK 293 cells, the Ca2+/calmodulin-dependent kinase activity of β7, the shortest variant, was much lower than that of either β (the longest one) or βe (the medium one), suggesting possible regulation of β CaMKII activity by alternative splicing
Low titers of measles antibody in mothers whose infants suffered from measles before eligible age for measles vaccination
<p>Abstract</p> <p>Background</p> <p>Resurgence or outbreak of measles recently occurred in both developed and developing countries despite long-standing widespread use of measles vaccine. Measles incidence in China has increased since 2002, particularly in infants and in persons ≥ 15 years of age. It is speculated that infants may acquire fewer measles IgG from their mothers, resulting in the reduced duration of protection during their early months of life. This study aimed to clarify the reason of increased susceptibility to measles in young infants in China. Measles IgG in 24 measles infants ≤ 9 months of age and their vaccinated mothers was quantitatively measured. The mean measles neutralizing titer in the vaccinated mothers and in 13 age-match women with the histories of clinical measles were compared.</p> <p>Results</p> <p>All the mothers were confirmed to be vaccinated successfully by the presence of measles IgG. Six vaccinated mothers were positive for measles IgM and had high concentrations of measles IgG and the neutralizing antibody, indicating underwent natural boosting. The mean measles neutralizing titer in 18 vaccinated mothers without natural boosting were significantly lower than that in 13 age-match women with the histories of clinical measles (1:37 vs 1:182, <it>P </it>< 0.05).</p> <p>Conclusions</p> <p>Our results suggest that infants born to mothers who acquired immunity to measles by vaccination may get a relatively small amount of measles antibody, resulting in loss of the immunity to measles before the vaccination age. Measures to improve the immunity in young infants not eligible for measles vaccination would be critical to interrupt the measles transmission in China.</p
Carbohydrate metabolism in grape cultivars that differ in sucrose accumulation
Sugar concentrations and sucrose-metabolism related enzyme activities in berries and leaves were investigated during berry development using grape cultivars with different sucrose concentrations. Sucrose concentration was significantly negatively related to acid invertase activity in berries. Acid invertase showed the lowest activities in berries of high-sucrose cultivars, ‘Honey Juice’ and ‘B180’, and the highest in tracesucrose cultivars, ‘Concord’, ‘Jingxiu’, and ‘Jingya’. Acid invertase activities in berries of low-sucrose cultivar ‘Canadice’ were between high- and trace-sucrose cultivars. There was no significant difference in glucose and fructose concentrations, the activities of neutral invertase, sucrose synthase and sucrose phosphate synthase in berries among high-, low- and trace-sucrose cultivars as acid invertase. Sugar concentrations and sucrose-metabolism related enzymes activities in leaves also did not show such difference among all cultivars. The results suggest that differences in sucrose concentration in berries among grape cultivars mainly be due to acid invertase activity. In addition, the final sucrose concentration in berries at maturity for a grape cultivar might be decided at véraison, and véraison is the key period for sucrose accumulation.
Validation of Collection 6 MODIS land surface temperature product using in situ measurements
Land surface temperature (LST) is an important physical quantity at the land-atmosphere interface. Since 2016 the Collection 6 (C6) MODIS LST product is publicly available, which includes three refinements over bare soil surfaces compared to the Collection 5 (C5) MODIS LST product. To encourage the use of the C6 MODIS LST product in a wide range of applications, it is necessary to evaluate the accuracy of the C6 MODIS LST product. In this study, we validated the C6 MODIS LST product using temperature-based method over various land cover types, including grasslands, croplands, cropland/natural vegetation mosaic, open shrublands, woody savannas, and barren/sparsely vegetated. In situ measurements were collected from various sites under different atmospheric and surface conditions, including seven SURFRAD sites (BND, TBL, DRA, FPK, GCM, PSU, and SXF) in the United States, three KIT sites (EVO, KAL, and GBB) in Portugal and Namibia, and three HiWATER sites (GBZ, HZZ, and HMZ) in China. The spatial representativeness of the in situ measurements at each site was separately evaluated during daytime and nighttime using all available clear-sky ASTER LST products at 90m spatial resolution. Only six sites during daytime are selected as sufficiently homogeneous sites despite the usually high spatial thermal heterogeneity, whereas during nighttime most sites can be considered to be thermally homogeneous and have similar LST and air temperature. The C6 MODIS LST product was validated using in situ measurements from the selected homogeneous sites during daytime and nighttime: except for the GBB site, large RMSE values (> 2 K) were obtained during daytime. However, if only satellite LST with a high spatial thermal homogeneity on the MODIS pixel scale are used for LST validation, the best daytime accuracy (RMSE<1.3 K) for the C6 MODIS LST product is achieved over the BND and DRA sites. Except for the DRA site, the RMSE values during nighttime are<2 K at the selected homogeneous sites. Furthermore, the accuracy of the C6 MODIS LST product was compared with that of the C5 MODIS LST product during nighttime at the selected homogeneous sites. Except for the GBB site, there are only small differences (< 0.4 K) between the RMSE values for the C5 and C6 MODIS LST products
Association of healthy lifestyle with incident cardiovascular diseases among hypertensive and normotensive Chinese adults
Background: Whether lifestyle improvement benefits in reducing cardiovascular diseases (CVD) events extend to hypertensive patients and whether these benefits differ between hypertensive and normotensive individuals is unclear. This study aimed to investigate the associations of an overall healthy lifestyle with the subsequent development of CVD among participants with hypertension and normotension.
Methods: Using data from the Suzhou subcohort of the China Kadoorie Biobank study of 51,929 participants, this study defined five healthy lifestyle factors as nonsmoking or quitting for reasons other than illness; nonexcessive alcohol intake; relatively higher physical activity level; a relatively healthy diet; and having a standard waist circumference and body mass index. We estimated the associations of these lifestyle factors with CVD, ischemic heart disease (IHD) and ischemic stroke (IS).
Results: During a follow-up of 10.1 years, this study documented 6,151 CVD incidence events, 1,304 IHD incidence events, and 2,243 IS incidence events. Compared to those with 0–1 healthy lifestyle factors, HRs for those with 4–5 healthy factors were 0.71 (95% CI: 0.62, 0.81) for CVD, 0.56 (95% CI: 0.42, 0.75) for IHD, and 0.63 (95% CI: 0.51, 0.79) for IS among hypertensive participants. However, we did not observe this association among normotensive participants. Stratified analyses showed that the association between a healthy lifestyle and IHD risk was stronger among younger participants, and the association with IS risk was stronger among hypertensive individuals with lower household incomes.
Conclusion: Adherence to a healthy lifestyle pattern is associated with a lower risk of cardiovascular diseases among hypertensive patients, but this benefit is not as pronounced among normotensive patients
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