Surface modification of CuS counter electrodes by hydrohalic acid treatment for improving interfacial charge transfer in quantum-dot-sensitized solar cells.

High charge transfer resistance and low electrocatalytic activity of counter electrodes (CEs) are mainly responsible for the poor photovoltaic performance of quantum-dot-sensitized solar cells (QDSSCs). Herein, a novel strategy has been successfully introduced for the first time to improve the electrocatalytic activity and charge transfer properties of a copper sulfide (CuS) CE by modifying it with the addition of hydrohalic acids (HHA). Through the suitable surface modification of HHA-incorporated CuS CE, the charge transfer from the external circuit to the CE surface was effectively facilitated.

Enhanced light absorption and charge recombination control in quantum dot sensitized solar cells using tin doped cadmium sulfide quantum dots.

The photovoltaic performance of quantum dot sensitized solar cells (QDSSCs) is limited due to charge recombination processes at the photoelectrode/electrolyte interfaces. We analyzed the effect of Sn ion incorporation into CdS quantum dots (QDs) deposited onto TiO substrates in terms of enhancing light absorption and retarding electron-hole recombination at the TiO/QDs/electrolyte interfaces. Sensitization involved depositing CdS QDs with different Sn concentrations on the surface of TiO using a facile and cost-effective successive ionic layer adsorption and reaction (SILAR) method.

Functional significance of activation of calcium/calmodulin-dependent protein kinase II in angiotensin II--induced vascular hyperplasia and hypertension.

We have reported that norepinephrine (NE) and angiotensin II (Ang II) increase CaM kinase II activity, which, in turn, activates cytosolic phospholipase A(2) (PLA(2)) and releases arachidonic acid. The products of arachidonic acid generated via cytochrome P-450 and lipoxygenase contribute to the development of hypertension and vascular smooth muscle cell (VSMC) hyperplasia. The purpose of this study was to investigate whether CaM kinase II contributes to VSMC proliferation elicited by NE and Ang II and to hypertension induced by Ang II.

Functional interaction of calcium-/calmodulin-dependent protein kinase II and cytosolic phospholipase A(2).

Calcium-/calmodulin-dependent protein kinase II (CaM kinase II), a decoder of Ca(2+) signals, and cytosolic phospholipase A(2) (cPLA(2)), an enzyme involved in arachidonate release, are involved in many physiological and pathophysiological processes. Activation of CaM kinase II in norepinephrine-stimulated vascular smooth muscle cells leads to activation of cPLA(2) and arachidonic acid release. Surface plasmon resonance, mass spectrometry, and kinetic studies show that CaM kinase II binds to cPLA(2) resulting in cPLA(2) phosphorylation on Ser-515 and an increase in its enzymatic activity.

Ca2+/calmodulin-dependent protein kinase II and cytosolic phospholipase A2 contribute to mitogenic signaling in myeloblastic leukemia U-937 cells.

The signaling mechanisms downstream of growth factor-stimulated proliferation in myeloid leukemia cells have not yet been fully elucidated. Recent evidence suggests that alternate pathways to the mitogen-activated protein kinase cascade are required. We have previously shown that Ca2+/calmodulin-dependent protein kinase II (CaM kinase II) activates cytosolic phospholipase A2 (cPLA2), which is involved in the proliferation of vascular smooth muscle cells.

Small GTP binding protein Ras contributes to norepinephrine-induced mitogenesis of vascular smooth muscle cells.

Norepinephrine stimulates release of arachidonic acid from tissue lipids. Arachidonic acid metabolites generated through the lipoxygenase and cytochrome P-450 pathways but not cyclooxygenase stimulate mitogen activated protein (MAP) kinase activity and proliferation of vascular smooth muscle cells (VSMC). Moreover, norepinephrine has been shown to activate the Ras/MAP kinase pathway through generation of cytochrome P450 metabolite of arachidonic acid, 20-hydroxyeicosatetraenoic acid (20-HETE).

Phospholipase D activation by norepinephrine is mediated by 12(s)-, 15(s)-, and 20-hydroxyeicosatetraenoic acids generated by stimulation of cytosolic phospholipase a2. tyrosine phosphorylation of phospholipase d2 in response to norepinephrine.

Norepinephrine (NE) stimulates phospholipase D (PLD) through a Ras/MAPK pathway in rabbit vascular smooth muscle cells (VSMC). NE also activates calcium influx and calmodulin (CaM)-dependent protein kinase II-dependent cytosolic phospholipase A(2) (cPLA(2)). Arachidonic acid (AA) released by cPLA(2)-catalyzed phospholipid hydrolysis is then metabolized into hydroxyeicosatetraenoic acids (HETEs) through lipoxygenase and cytochrome P450 4A (CYP4A) pathways.

20-Hydroxyeicosatetraenoic acid mediates angiotensin ii-induced phospholipase d activation in vascular smooth muscle cells.

Angiotensin II (Ang II) activates cytosolic phospholipase A(2) (cPLA(2)) and phospholipase D (PLD) in rabbit vascular smooth muscle cells (VSMCs). Ang II also activates ras/mitogen-activated protein (MAP) kinase in VSMCs; this activation is mediated by 20-hydroxyeicosatetraenoic acid (HETE) and 12(S)-HETE, which are metabolites of arachidonic acid generated by cytochrome P450 4A and lipoxygenase, respectively, produced on activation of cPLA(2). The purpose of this study was to determine if Ang II-induced PLD activation in VSMCs is mediated through the ras/extracellular signal-regulating kinase (ERK) pathway by arachidonic acid metabolites that are generated consequent to cPLA(2) stimulation.

Angiotensin II-induced hypertension: contribution of Ras GTPase/Mitogen-activated protein kinase and cytochrome P450 metabolites.

We reported that norepinephrine and angiotensin II (Ang II) activate the Ras/mitogen-activated protein (MAP) kinase pathway primarily through the generation of cytochrome P450 (CYP450) metabolites. The purpose of the present study was to determine the contribution of Ras and CYP450 to Ang II-dependent hypertension in rats. Infusion of Ang II (350 ng/min for 6 days) elevated mean arterial blood pressure (MABP) (171+/-3 mm Hg for Ang II versus 94+/-5 for vehicle group, P<0.

Ras/mitogen-activated protein kinase mediates norepinephrine-induced phospholipase D activation in rabbit aortic smooth muscle cells by a phosphorylation-dependent mechanism.

Phospholipase D (PLD) activity is regulated by phosphatidylinositol 4,5-biphosphate, protein kinase C (PKC), ADP-ribosylation factor, and Rho. The present study was designed to investigate the mechanism of norepinephrine (NE)-mediated PLD activation in rabbit aortic vascular smooth muscle cells (VSMC). NE (10 microM) caused activation of PLD, as measured by the production of phosphatidylethanol in [(3)H]oleic acid-labeled cells.

Contribution of Ras GTPase/MAP kinase and cytochrome P450 metabolites to deoxycorticosterone-salt-induced hypertension.

We recently reported that norepinephrine and angiotensin II activate the Ras/mitogen-activated protein (MAP) kinase pathway through generation of a cytochrome P450 (CYP450) and lipoxygenase metabolites. The purpose of this study was to determine the contribution of Ras/MAP kinase to deoxycorticosterone acetate (DOCA)-salt-induced hypertension in rats. Administration of DOCA and 1% saline drinking water to uninephrectomized rats for 6 weeks significantly elevated mean arterial blood pressure (MABP) (166+/-5 mm Hg, n=19) compared with that of normotensive controls (95+/-5 mm Hg, n=7) (P<0.

beta-hexosaminidase-induced activation of p44/42 mitogen-activated protein kinase is dependent on p21Ras and protein kinase C and mediates bovine airway smooth-muscle proliferation.

Late-phase and sustained activation of p44/42(MAPK) has been reported to be a critical factor in cell mitogenesis. We therefore hypothesized that p44/42(MAPK) is involved in mannosyl-rich glycoprotein-induced mitogenesis in bovine airway smooth-muscle cells (ASMC). Treatment of adherent ASMC with beta-hexosaminidase A (Hex A, 50 nM), an endogenous mannosyl-rich glycoprotein, resulted in a late-onset (30-min) activation of p44/42(MAPK) that lasted for 4 h.

20-Hydroxyeicosatetraenoic acid mediates calcium/calmodulin-dependent protein kinase II-induced mitogen-activated protein kinase activation in vascular smooth muscle cells.

Norepinephrine (NE) and angiotensin II (Ang II), by promoting extracellular Ca2+ influx, increase Ca2+/calmodulin-dependent kinase II (CaMKII) activity, leading to activation of mitogen-activated protein kinase (MAPK) and cytosolic phospholipase A2 (cPLA2), resulting in release of arachidonic acid (AA) for prostacyclin synthesis in rabbit vascular smooth muscle cells. However, the mechanism by which CaMKII activates MAPK is unclear. The present study was conducted to determine the contribution of AA and its metabolites as possible mediators of CaMKII-induced MAPK activation by NE, Ang II, and epidermal growth factor (EGF) in vascular smooth muscle cells.

Cytochrome P-450 metabolites mediate norepinephrine-induced mitogenic signaling.

Norepinephrine (NE) stimulates release of arachidonic acid (AA) from tissue lipids in blood vessels, which is metabolized via cyclooxygenase, lipoxygenase (LO), and cytochrome P-450 (CYP-450) pathways to biologically active products. Moreover, NE and AA have been shown to stimulate proliferation of vascular smooth muscle cells (VSMCs) of rat aorta. The purpose of this study was to determine the possible contribution of AA and its metabolites to NE-induced mitogenesis in VSMCs of rat aorta and the underlying mechanism of their actions.

Signal transduction mechanisms involved in angiotensin-(1-7)-stimulated arachidonic acid release and prostanoid synthesis in rabbit aortic smooth muscle cells.

This study investigated the signal transduction mechanisms of angiotensin-(1-7) [Ang-(1-7)]- and Ang II-stimulated arachidonic acid (AA) release for prostaglandin (PG) production in rabbit aortic vascular smooth muscle cells. Ang II and Ang-(1-7) enhanced AA release in cells prelabeled with [3H]AA. However, 6-keto-PGF1 alpha synthesis produced by Ang II was much less than that caused by Ang-(1-7).

Calcium/calmodulin-dependent protein kinase IIalpha mediates activation of mitogen-activated protein kinase and cytosolic phospholipase A2 in norepinephrine-induced arachidonic acid release in rabbit aortic smooth muscle cells.

We have investigated the contribution of Ca2+/calmodulin-dependent protein kinase II (CaM kinase II) and mitogen-activated protein kinase (MAP kinase) in norepinephrine (NE)-induced arachidonic acid (AA) release in rabbit aortic vascular smooth muscle cells (VSMC). NE enhanced release of AA via activation of cytosolic phospholipase A2 (cPLA2) but not secretory PLA2 in VSMC prelabeled with [3H]AA. NE (10 microM) enhanced CaM kinase II and MAP kinase activity.

Identification of dehydrin-like proteins responsive to chilling in floral buds of blueberry (Vaccinium, section Cyanococcus).

The level of three major polypeptides of 65, 60, and 14 kD increased in response to chilling unit accumulation in floral buds of a woody perennial, blueberry (Vaccinium, section Cynaococcus). The level of the polypeptides increased most dramatically within 300 h of chilling and decreased to the prechilling level with the initiation of budbreak. Cold-hardiness levels were assessed for dormant buds of Vaccinium corymbosum and Vaccinium ashei after different chilling treatments until the resumption of growth.