4,986 research outputs found
Sn-Nanorod-Supported Ag Nanoparticles as Efficient Catalysts for Electroless Deposition of Cu Conductive Tracks
No full textThe applications of tin are extremely
wide-ranging, in fields as
diverse as Li-ion batteries, catalysis, and electronic packaging.
It is always significant but still remains a great challenge to develop
facile and efficient routes to synthesize Sn nanostructures. Herein,
we report a facile chemical method to synthesize a Sn nanorod crystal
at room temperature, and Ag ions are subsequently introduced to form
the Sn-nanorod-supported Ag nanoparticles hybrid structure (Sn/Ag
nanorods). The Sn/Ag nanorods exhibit comparable activity to the commercial
Pd black in catalyzing the electroless copper deposition (ECD) reaction
that is indispensable to fabricate printed circuit boards (PCBs).
Furthermore, a screen printable adhesive is prepared by mixing the
as-synthesized Sn/Ag nanorod powders and epoxy resin to fabricate
activator patterns on epoxy laminate (EPL) and flexible substrates
including polyethylene terephthalate (PET) and polytetrafluoroethylene
(PTFE) fiber film. The printed areas are finally metalized by the
ECD process to obtain the copper coatings with designed patterns that
are confirmed to exhibit excellent electrical conductivity and flexibility
<i>MSH3</i>-deficient (vs proficient) cells are more sensitive to SN-38 and oxaliplatin in contrast to 5-FU.
No full text<p>A–C, MTS assay in HCT116 (<i>MLH1−/MSH3−</i>), HCT116+3 (<i>MLH1+/MSH3−</i>), and HCT116+3+5 (<i>MLH1+/MSH3+</i>) cells treated with SN-38 (A), oxaliplatin (B) or 5-FU (C). D–F, Clonogenic survival of these same cell lines treated for 48 h with SN-38 (D), oxaliplatin (E), or 5-FU (F). Data are presented as mean ± standard errors <i>vs</i> controls for at least 3 independent experiments. Statistical significance was determined by a two-sided Student's t test (* P<0.05; † P<0.01).</p
Effect of 5-Fluorouracil Treatment on SN-38 Absorption from Intestine in Rats
No full text5-Fluorouracil (5-FU)-based chemotherapies with irinotecan have been applied for the treatment of cancers, and a common dose-limiting toxicity is neutropenia and diarrhea. In this study, we investigated the effect of 5-FU treatment on expression levels of drug transporters for SN-38 transportation and SN-38 absorption from the intestine following 5-FU treatment. Expression levels of several drug transporters and nuclear receptors in rats after 5-FU treatment were evaluated. SN-38 absorption from the intestine was evaluated by SN-38 concentration levels in serum following SN-38 injection into the intestine of 5-FU treated rats. The levels of renal multidrug resistance protein 2 (Mrp2) on day 4 after treatment (400 mg/kg) showed significant upregulation, 359.2 ± 33.2% (mean ± S.E.) of control. Mrp2 levels in the intestine were downregulated to 26.2 ± 8.4% of control. 5-FU treatment (400 mg/kg) also significantly downregurated expression levels of P-glycoprotein (P-gp) and breast cancer resistance protein (Bcrp) to 41.2 ± 14.7%, 15.7 ± 4.3% of control, respectively. To evaluate SN-38 absorption from the intestine, SN-38 was loaded in to the intestine on day 4 after 5-FU treatment. Pretreatment with 5-FU significantly increased SN-38 concentration in the blood 30, 60 and 90 min after SN-38 administration. The area under the curve for SN-38 in the 5-FU group was significantly higher than in vehicle groups. 5-FU treatment decreased expression levels of P-glycoprotein and Bcrp in intestine. The present study suggests that combination chemotherapy of 5-FU with irinotecan (CPT-11) may elevate SN-38 absorption from intestine
<i>Operando</i> Spectroscopic Analysis of Axial Oxygen-Coordinated Single-Sn-Atom Sites for Electrochemical CO<sub>2</sub> Reduction
No full textSn-based materials have been demonstrated
as promising catalysts
for the selective electrochemical CO2 reduction reaction
(CO2RR). However, the detailed structures of catalytic
intermediates and the key surface species remain to be identified.
In this work, a series of single-Sn-atom catalysts with well-defined
structures is developed as model systems to explore their electrochemical
reactivity toward CO2RR. The selectivity and activity of
CO2 reduction to formic acid on Sn-single-atom sites are
shown to be correlated with Sn(IV)-N4 moieties axially
coordinated with oxygen (O–Sn–N4), reaching
an optimal HCOOH Faradaic efficiency of 89.4% with a partial current
density (jHCOOH) of 74.8 mA·cm–2 at −1.0 V vs reversible hydrogen electrode
(RHE). Employing a combination of operando X-ray
absorption spectroscopy, attenuated total reflectance surface-enhanced
infrared absorption spectroscopy, Raman spectroscopy, and 119Sn Mössbauer spectroscopy, surface-bound bidentate tin carbonate
species are captured during CO2RR. Moreover, the electronic
and coordination structures of the single-Sn-atom species under reaction
conditions are determined. Density functional theory (DFT) calculations
further support the preferred formation of Sn–O–CO2 species over the O–Sn–N4 sites,
which effectively modulates the adsorption configuration of the reactive
intermediates and lowers the energy barrier for the hydrogenation
of *OCHO species, as compared to the preferred formation of *COOH
species over the Sn–N4 sites, thereby greatly facilitating
CO2-to-HCOOH conversion
Combination index of tenovin-6 plus docetaxel, SN-38, cisplatin, and 5-FU in gastric cancer cells.
No full text<p>The cytotoxic effects of combining docetaxel, SN-38, cisplatin, and 5-FU with tenovin-6 were determined by isobologram. Combination index (CI) >1.3, antagonism; CI = 1.1–1.3 moderate antagonism; CI = 0.9–1.1 additive effect; CI = 0.8–0.9 slight synergism; CI = 0.6–0.8 moderate synergism; CI = 0.4–0.6 synergism; and CI = 0.2–0.4 strong synergism. Bold and italic numbers indicate synergistic effects. †: NUGC-3 was treated at 0.5 µM cisplatin.</p
Ordering of organic molecules on templated surfaces
No full textThis thesis describes the controlled growth of molecular nanostructures using modified metallic and semiconductor surfaces. The Ag/Si(lll)-(root3 x root3),the Sn/Cu(100) surface alloy system and the Bi/Si(100) nanolines and (2xn) surfaces were all investigated as suitable substrates for the controlled growth of pentacene, (C22H14) or trimesic acid, (C6H3(COOH)3) organic molecules. The following techniques were used in this study; Scanning Tunnelling Microscopy (STM), Low Energy Electron Diffraction (LEED), Normal Incident X-Ray Standing Waves (NIXSW) and Temperature Programmed Desorption (TPD).
The room temperature growth and ordering of trimesic acid on the AgfSi(ll1)-(root3 x root3) surface was investigated. An oblique unit cell was determined and a model proposed for the highly ordered close-packed domains.
The discovery of a new submonolayer phase on Sn/Cu(100) and the re-examined known phase are discussed. New models for these reconstructions are proposed. Adsorption of trimesic acid at room temperature on the clean substrate the lowest Sn coverage phase were studied. Two new Sn coverage dependent structures were discovered and bonding schemes in upright and flat orientations are discussed.
BifSi(100)-(2xn) surface was exploited as a template for the ordered growth of pentacene, which exhibited orientation specific adsorption. The Bi/Si(100)-(2xn) single domain surface created on vicinal silicon was used to test the suitable of Daresbury 4.2 beamline for NIXSW Imaging experiments and the quality of the results are discussed
A trio of gamma-ray burst supernovae : GRB 120729A, GRB 130215A/SN 2013ez, and GRB 130831A/SN 2013fu
No full textWe present optical and near-infrared (NIR) photometry for three gamma-ray burst supernovae (GRB-SNe): GRB 120729A, GRB 130215A/SN 2013ez, and GRB 130831A/SN 2013fu. For GRB 130215A/SN 2013ez, we also present optical spectroscopy at t − t0 = 16.1 d, which covers rest-frame 3000–6250 Å. Based on Fe ii λ5169 and Si ii λ6355, our spectrum indicates an unusually low expansion velocity of ~4000–6350 km s-1, the lowest ever measured for a GRB-SN. Additionally, we determined the brightness and shape of each accompanying SN relative to a template supernova (SN 1998bw), which were used to estimate the amount of nickel produced via nucleosynthesis during each explosion. We find that our derived nickel masses are typical of other GRB-SNe, and greater than those of SNe Ibc that are not associated with GRBs. For GRB 130831A/SN 2013fu, we used our well-sampled R-band light curve (LC) to estimate the amount of ejecta mass and the kinetic energy of the SN, finding that these too are similar to other GRB-SNe. For GRB 130215A, we took advantage of contemporaneous optical/NIR observations to construct an optical/NIR bolometric LC of the afterglow. We fit the bolometric LC with the millisecond magnetar model of Zhang & Mészáros (2001, ApJ, 552, L35), which considers dipole radiation as a source of energy injection to the forward shock powering the optical/NIR afterglow. Using this model we derive an initial spin period of P = 12 ms and a magnetic field of B = 1.1 × 1015 G, which are commensurate with those found for proposed magnetar central engines of other long-duration GRBs
On Isometric Extension in the Space sn(H)
No full textWe study the problem of isometric extension on a sphere of the space sn(H). We give an affirmative answer to Tingley’s problem in the space sn(H)
Silica supported Sn catalysts with tetrahedral Sn sites for selective isomerization of glucose to fructose
No full textLewis acid catalyzed isomerization of glucose to fructose is an important reaction for production of renewable chemicals. Here, we show the synthesis of an active and selective Lewis acid catalyst for this reaction by controlling Sn dispersion on SBA15. Sn loading of 1 wt. % over SBA15 (Sn/SBA15) maximized the formation of tetrahedral Sn species on the catalyst surface. Increasing the loading or changing support caused formation of SnO2 clusters which reduced fructose selectivity. A mechanism based on condensation of Sn with silanol group of SBA15 is proposed. The catalyst showed high selectivity of 93 % after 2 h with 57 % fructose yield. The Lewis acid catalyzed isomerization of glucose was proven by isotopic tracer study using D-glucose-2-d. The catalyst deactivated in the third cycle owing to byproduct deposition, but the activity was restored by recalcining the catalyst
Sn-Based Electrocatalyst Stability: A Crucial Piece to the Puzzle for the Electrochemical CO<sub>2</sub>Reduction toward Formic Acid
No full textNowadays, Sn-based electrocatalysts for the electrochemical CO2 reduction reaction (eCO2RR) toward formic acid have been reported to reach industrially relevant current densities and Faradaic efficiencies approaching 100%. However, electrocatalyst stability remains inadequate and appears to be a crucial piece to the puzzle, as lifetimes in the range of several thousands of hours should be reached for practical application and economic viability. Here, we provide insights into stability issues related to Sn-based electrocatalysts and electrolyzers for formic acid production. By determining the chemical and physical phenomena that occur during the electrochemical reduction reaction on the surface and bulk of Sn-based catalysts, we intend to elucidate the most common degradation mechanisms that impair long-term electrocatalytic activity of these catalysts. Moreover, highlighting the importance of correctly selected process conditions and an optimized reactor design allows us to unveil all necessary aspects for a stable Sn-based eCO2RR toward formic acid.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Large Scale Energy Storag
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