11 research outputs found
Linker-Free Modification Of TiO2 Nanorods With PbSe Nanocrystals
We report on a colloidal synthesis of Pbse/TiO2 heterostructures, comprising small-diameter PbSe nanocrystals epitaxially grown onto the surface of TiO2 nanorods. The deposition of lead selenide onto prefabricated TiO2 nanocrystals proceeds via formation of a thin PbSe shell that subsequently breaks into sub-2-nm islands. Additional precursor injections are then used to increase the size of PbSe nanocrystals up to 5 nm. In the case of small-size PbSe, a 2.1-ns transfer of photoinduced carriers into TiO2 domain was evidenced through quenching of the PbSe band gap emission. Overall, the present synthesis demonstrates a colloidal approach to all-inorganic modification of TiO2 surfaces with semiconductor nanocrystals, which provides a viable alternative to a more common supramolecular assembly of nanocrystal-oxide composites
Synthesis Of Pbs/tio2 Colloidal Heterostructures For Photovoltaic Applications
We report on heteroepitaxial growth of nearly monodisperse PbS nanocrystals onto the surface of TiO2 nanoparticles via colloidal hot-injection routes. Fabricated PbS/TiO2 nanocomposites can be dispersed in nonpolar solvents, which enables an easy solution processing of these materials into mesoporous films for use as light-absorbing layers in nanocrystal-sensitized solar cells. High-temperature deposition of the sensitizer material allows controlling both the size and the number of PbS domains grown onto TiO2 nanoparticles, whereby providing synthetic means for tuning the absorbance spectrum of PbS/TiO2 nanocomposites and simultaneously enhancing their photocatalytic response in the visible and near-infrared. Compared with conventional ionic bath deposition of PbS semiconductors onto TiO2, the reported method results in an improved nanocrystal quality and narrower distribution of PbS sizes; meanwhile, the use of hot-temperature deposition of PbS (T = 180 degrees C) promotes the formation of near-epitaxial relationships between PbS and TiO2 domains, leading to fewer interfacial defects. The photovoltaic response of pyridine-treated PbS/TiO2 nanocomposites was investigated using a two-electrode cell filled with polysulfide electrolyte. The measured photocurrent compared favorably to that of PbS/TiO2 electrodes fabricated via chemical bath deposition
Silicon oxide nanowires:Facile and controlled large area fabrication of vertically oriented silicon oxide nanowires for photoluminescence and sensor applications
Silicon Oxide Nanowires: Facile and Controlled Large Area Fabrication of Vertically Oriented Silicon Oxide Nanowires for Photoluminescence and Sensor Applications
We describe a technique for the fabrication
of dense and patterned
arrays of aligned silicon oxide nanowires for applications in surface
modification, optoelectronic, and electromechanical based devices.
Conventional techniques for the fabrication of silicon oxide nanowires
based on the vapor–liquid–solid (VLS) chemical vapor
deposition (CVD) processes involve the use of high temperatures and
catalysts. We demonstrate a technique that extends the use of a plasma
thermal reactive ion etching for the fabrication of aligned silicon
oxide nanowires with aspect ratios extending up to 20 and lengths
exceeding 1 μm. The process incorporates phase separated PS-b-P4VP
block copolymer loaded with an iron salt. The iron salt preferentially
segregates into the P4VP layer and during an O<sub>2</sub> etch is
not removed but forms a hexagonally packed array on the silicon oxide
substrate. Further etching with CHF<sub>3</sub>/O<sub>2</sub> gas
mixture over time can generate nanodots, to nanopillars, and then
nanowires of silicon oxide. The photoluminescence property of the
as-fabricated nanowire arrays as well as the parasitic ferromagnetic
effect from the iron oxide-tipped section of the wires resulting in
coalescence under an scanning electron microscope (SEM) are demonstrated.
This technique is simpler compared to existing VLS fabrication approaches
and can be used for the direct fabrication of patterned arrays of
nanowires when a laser interference ablation step is incorporated
into the fabrication procedure
Silicon Oxide Nanowires: Facile and Controlled Large Area Fabrication of Vertically Oriented Silicon Oxide Nanowires for Photoluminescence and Sensor Applications
We describe a technique for the fabrication
of dense and patterned
arrays of aligned silicon oxide nanowires for applications in surface
modification, optoelectronic, and electromechanical based devices.
Conventional techniques for the fabrication of silicon oxide nanowires
based on the vapor–liquid–solid (VLS) chemical vapor
deposition (CVD) processes involve the use of high temperatures and
catalysts. We demonstrate a technique that extends the use of a plasma
thermal reactive ion etching for the fabrication of aligned silicon
oxide nanowires with aspect ratios extending up to 20 and lengths
exceeding 1 μm. The process incorporates phase separated PS-b-P4VP
block copolymer loaded with an iron salt. The iron salt preferentially
segregates into the P4VP layer and during an O<sub>2</sub> etch is
not removed but forms a hexagonally packed array on the silicon oxide
substrate. Further etching with CHF<sub>3</sub>/O<sub>2</sub> gas
mixture over time can generate nanodots, to nanopillars, and then
nanowires of silicon oxide. The photoluminescence property of the
as-fabricated nanowire arrays as well as the parasitic ferromagnetic
effect from the iron oxide-tipped section of the wires resulting in
coalescence under an scanning electron microscope (SEM) are demonstrated.
This technique is simpler compared to existing VLS fabrication approaches
and can be used for the direct fabrication of patterned arrays of
nanowires when a laser interference ablation step is incorporated
into the fabrication procedure
Table1_Methanolic Moringa oleifera leaf extract protects against epithelial barrier damage and enteric bacterial translocation in intestinal I/R: Possible role of caspase 3.doc
Background: Activation of caspase 3 has been implicated in the pathogenesis of I/R injury in various organs, but there is a paucity of data on its role in IIRI. Also, no reports were found on the beneficial role of methanolic Moringa oleifera leaf extract (MMOLE) in IIRI. This study investigated the involvement of caspase 3 in IIRI, and the impact of MMOLE in IIRI.Methods: Male Wistar rats were randomized into five groups; the sham-operated group that was sham-operated and received 0.5 ml of distilled water for 7 days prior to sham surgery, and the IIRI, febuxostat (FEB) +IIRI, low dose MMOLE (LDMO)+IIRI, and high dose MMOLE (HDMO)+IIRI groups that underwent I/R and also received 0.5 ml of distilled water, 10 mg/kg of febuxostat, 200 mg/kg of MMOLE, and 400 mg/kg of MMOLE respectively for 7 days prior to I/R. Markers of hepatic function, oxidative stress, and inflammation as well as enteric bacterial translocation and histoarchitecture integrity of intestinal and hepatic tissues were evaluated. The bioactive components of MMOLE were also determined by GC-MS.Results: As revealed by GC-MS, the active bioactive components of MMOLE were thiosemicarbazone, hydrazine, 1,3-dioxolane, octanoic acid, 1,3-benzenediamine, 9-octadecenoic acid, oleic acid, nonadecanoic acid, 3-undecanone, phosphonic acid, and cyclopentanecarboxylic acid. MMOLE alleviated IIRI-induced rise in intestinal and hepatic injury markers, malondialdehyde, TNF-α, IL-6, and myeloperoxidase activities. MMOLE improved IIRI-induced suppression of reduced glutathione, thiol and non-thiol proteins, and superoxide dismutase, catalase and glutathione peroxidase activities. These were associated with suppression of IIRI-induced caspase 3 activity and bacterial translocation. Histopathological evaluation revealed that MMOLE attenuated IIRI-induced alterations in intestinal and hepatic histoarchitecture integrity. MMOLE also militated against increased absolute and relative intestinal and hepatic weight, intestinal and hepatic injuries, epithelial mucosal barrier dysfunction, and enteric bacterial translocation associated with IIRI by downregulating oxidative stress-mediated activation of caspase 3.Conclusion: IIRI is associated with a rise in caspase 3 activity. Also, MMOLE confers protection against IIRI, possibly due to its constituent bioactive molecules, especially hydrazine, 9-octadecenoic acid, 1,3-dioxolane, oleic acid, and nonadecanoic acid.</p
DataSheet1_Methanolic Moringa oleifera leaf extract protects against epithelial barrier damage and enteric bacterial translocation in intestinal I/R: Possible role of caspase 3.doc
Background: Activation of caspase 3 has been implicated in the pathogenesis of I/R injury in various organs, but there is a paucity of data on its role in IIRI. Also, no reports were found on the beneficial role of methanolic Moringa oleifera leaf extract (MMOLE) in IIRI. This study investigated the involvement of caspase 3 in IIRI, and the impact of MMOLE in IIRI.Methods: Male Wistar rats were randomized into five groups; the sham-operated group that was sham-operated and received 0.5 ml of distilled water for 7 days prior to sham surgery, and the IIRI, febuxostat (FEB) +IIRI, low dose MMOLE (LDMO)+IIRI, and high dose MMOLE (HDMO)+IIRI groups that underwent I/R and also received 0.5 ml of distilled water, 10 mg/kg of febuxostat, 200 mg/kg of MMOLE, and 400 mg/kg of MMOLE respectively for 7 days prior to I/R. Markers of hepatic function, oxidative stress, and inflammation as well as enteric bacterial translocation and histoarchitecture integrity of intestinal and hepatic tissues were evaluated. The bioactive components of MMOLE were also determined by GC-MS.Results: As revealed by GC-MS, the active bioactive components of MMOLE were thiosemicarbazone, hydrazine, 1,3-dioxolane, octanoic acid, 1,3-benzenediamine, 9-octadecenoic acid, oleic acid, nonadecanoic acid, 3-undecanone, phosphonic acid, and cyclopentanecarboxylic acid. MMOLE alleviated IIRI-induced rise in intestinal and hepatic injury markers, malondialdehyde, TNF-α, IL-6, and myeloperoxidase activities. MMOLE improved IIRI-induced suppression of reduced glutathione, thiol and non-thiol proteins, and superoxide dismutase, catalase and glutathione peroxidase activities. These were associated with suppression of IIRI-induced caspase 3 activity and bacterial translocation. Histopathological evaluation revealed that MMOLE attenuated IIRI-induced alterations in intestinal and hepatic histoarchitecture integrity. MMOLE also militated against increased absolute and relative intestinal and hepatic weight, intestinal and hepatic injuries, epithelial mucosal barrier dysfunction, and enteric bacterial translocation associated with IIRI by downregulating oxidative stress-mediated activation of caspase 3.Conclusion: IIRI is associated with a rise in caspase 3 activity. Also, MMOLE confers protection against IIRI, possibly due to its constituent bioactive molecules, especially hydrazine, 9-octadecenoic acid, 1,3-dioxolane, oleic acid, and nonadecanoic acid.</p