817 research outputs found
Strong enhancement of chlorophyll a concentration by a weak typhoon
Recent studies demonstrate that chlorophyll a (chl a) concentrations in the
surface ocean can be significantly enhanced due to typhoons. The present study
investigated chl a concentrations in the middle of the South China Sea (SCS)
from 1997-2007. Only the Category1 (minimal) Typhoon Hagibis (2007) had a
notable effect on the chl a concentrations. Typhoon Hagibis had a strong
upwelling potential due to its location near the equator, and the forcing time
of the typhoon (>82 h) was much longer than the geostrophic adjustment time
(~63 h). The higher upwelling velocity and the longer forcing time increased
the depth of the mixed-layer, which consequently induced a strong phytoplankton
bloom that accounted for about 30% of the total annual chl a concentration in
the middle of the SCS. The implication is that the forcing time of a typhoon
should be long enough to establish a strong upwelling and consequently for the
induction of significant upper ocean responses.Comment: Typhoon-Ocean Environment interaction
Critical Differences in Magnitude and Duration of N-methyl-D-aspartate (NMDA) Receptor Activation between Long-term Potentiation (LTP) and Long-term Depression (LTD) Induction
The induction of both long-term potentiation (LTP) and long-term depression (LTD) in the hippocampal CA1 region is triggered by the activation of N-methyl-D-aspartate (NMDA) receptors and the subsequent postsynaptic intracellular Ca2+ increase. However, how NMDA receptor activation differs between LTP and LTD induction is unclear. In the present study, we examined the eff ects of the magnitude and duration of NMDA receptor activation on the induction of LTP and LTD. Partial blockage of NMDA receptors by a low concentration of aminophosphonovaleric acid (APV)(2 μM) prevented the induction of LTP, but not LTD. In contrast, a high concentration of APV(25 μM) blocked both LTP and LTD. Tetanus stimulation-induced LTP was impaired when hippocampal slices were given
the tetanus stimulation for more than 5 min. Under partial blockage of NMDA receptors, the prolonged-tetanus stimulation induced LTD but not LTP. This phenomenon was mimicked by the application of glutamate to the slices. Finally, LTD induced by prolonged activation of NMDA receptors was not aff ected by inhibition of the desensitization of α-amino-3-hydroxy-5 methylisoxazole-4-propionic acid (AMPA) receptors. These results suggest that critical diff erences exist between the induction of LTP and that of LTD in terms of both the magnitude and the duration of NMDA receptor activation. The duration of the increase in intracellular Ca2+ concentration may be critical for determining whether LTP or LTD induction occurs.</p
Repeated application of anodal direct current produces regional dominance in histamine-elicited cyclic AMP accumulation in rabbit cerebral cortex.
A unilateral 30-min application of anodal direct current to the promotor cortex of rabbits was repeated 10 times, and cyclic AMP accumulation in response to histamine was investigated in slices of different cortical areas. Polarization with 1.0 microA decreased the cyclic AMP accumulation in the cortical area contralateral to the polarization, by which regional dominance in cyclic AMP accumulation was produced in the polarized cortex. In contrast, the regional difference in cyclic AMP accumulation was reversed when 10.0 or 30.0 microA was applied. The histamine-elicited accumulation of cyclic AMP was almost completely inhibited by the selective H2-receptor antagonist cimetidine. These results suggest that repeated anodal polarization regionally alters H2-receptor-mediated cyclic AMP generation in the cortex depending on the intensity of the polarizing currents and this pattern of cyclic AMP accumulation is responsible for the characteristic motor behavior induced by anodal polarization.</p
Serum soluble ST2 is associated with ER-positive breast cancer
BACKGROUND: ST2, a member of the interleukin (IL)-1receptor family, regulates Th1/Th2 immune responses in autoimmune and inflammatory conditions. However, the role of ST2 signaling in tumor growth and metastasis of breast cancers has not been investigated. This study investigated the possible role of soluble ST2 (sST2) in breast cancer. METHODS: The serum levels of IL-33, sST2, and vascular endothelial growth factor (VEGF) in 150 breast cancer patients and 90 healthy women were measured by enzyme-linked immunosorbent assay. Estrogen receptor(ER), progesterone receptor, human epithelial receptor (HER)-2, and cell cycle regulated protein Ki-67 were measured. Clinical stage, tumor size, lymph node metastasis, and histological type were also recorded. RESULTS: The serum levels of sST2, IL-33, and VEGF were significantly higher in breast cancer patients than in the control group (Pâ<â0.05, each). Serum sST2 levels in ER-positive breast cancer patients were significantly associated with age, histological type, clinical stage, tumor size, and Ki-67 status (Pâ<â0.05, each). Moreover, the serum levels of IL-33 and sST2 in breast cancers significantly correlated with VEGF levels (IL-33: râ=â0.375, Pâ<â0.0001; sST2: râ=â0.164, P =â0.045). Serum levels of sST2, IL-33, and VEGF decreased after modified radical mastectomy in ER-positive breast cancers. Serum levels of IL-33, sST2, and VEGF and clinicopathological factors were not significantly correlated with disease-free survival and overall survival of ER-positive breast cancer women during follow-up. CONCLUSION: Serum sST2 levels in ER-positive breast cancer patients are significantly associated with factors that indicate poor prognosis
Dual Effects of Cortical Polarization on Peripheral Motor Activity in the Rabbit
Anodal direct currents at intensities ranging from 0.3 to 30.0 microA were unilaterally applied for 30 min once a day to the premotor area of the rabbit cerebral cortex. The anodal polarization was repeated 10 times at intervals of 2-3 days, and the effect on the motor activity of the forelimbs during and after each polarization trial was compared with that before polarization. Peripheral motor activity was classified as either gentle flexion of forelimbs or struggle with violent movement of forelimbs. A current of 0.3 microA caused no change in motor behavior. Flexion of the forelimb contralateral to the polarized cortex was clearly increased when a polarizing current of 1.0 or 3.0 microA was applied, and peak flexion was observed between the third and seventh polarization trials. A current of 10 or 30 microA had no effect on forelimb flexion. Conversely, forelimb struggle on both sides was decreased when 10.0 or 30.0 microA, but not 1.0 or 3.0 microA, was applied. These results show that anodal polarization of the cerebral cortex exerts dual effects on peripheral motor activity, probably through changes in cortical excitability associated with the current intensity.</p
Bis[N,N-bisÂ(1-allyl-1H-benzimidazol-2-ylmethyl-ÎșN 3)benzylÂamine-ÎșN]cadmium dipicrate
The crystal structure of the title compound, [Cd(C29H29N5)2](C6H2N3O7)2, consists of CdII complex cations and picrate anions. In the complex cation, the CdII ion is chelated by two bisÂ(1-allylÂbenzimidazol-2-ylmethÂyl)benzylÂamine (babb) ligands in a distorted octaÂhedral geometry. Extensive CâHâŻO hydrogen bonding occurs between cations and anions in the crystal structure
Effects of polymerase, template dilution and cycle number on PCR based 16 S rRNA diversity analysis using the deep sequencing method
The double inhibition of PDK1 and STAT3-Y705 prevents liver metastasis in colorectal cancer.
As a key glycolysis enzyme, the significance of pyruvate dehydrogenase kinase 1 (PDK1) in the development of colorectal cancer (CRC) remains unknown. This study revealed that the prognosis of CRC patients with high levels of PDK1 was poor, and PDK1 knockdown significantly reduced liver metastasis of CRC in both nude mice and immune competent BALB/C mice. When combined with cryptotanshinone (CPT), an inhibitor of STAT3-p-Y705, the liver metastasis was further inhibited. PDK1 knockdown obviously increased reactive oxygen species level in anoikis conditions and subsequently resulted in an elevated anoikis, but the combination of PDK1 knockdown and CPT showed a reduced effect on anoikis. Based on this discrepancy, the adherence ability of CRC cells to matrix protein fibronectin was further detected. It showed that PDK1 knockdown significantly decreased the adherence of CRC cells to fibronectin when combined with CPT. These results suggest that inhibition of PDK1 can decrease the surviving CRC cells in blood circulation via up-regulation of anoikis, and inhibition of STAT3-p-Y705 can prevent it to settle down on the liver premetastatic niche, which ultimately reduces liver metastasis
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