Using a sulfur-bearing silane to improve rubber formulations for potential use in industrial rubber articles

The availability of the coupling agent bis (3-triethoxysilylpropyl)-tetrasulfide (TESPT) has provided an opportunity for enhancing the reinforcing capabilities of precipitated amorphous white silica in rubber. Styrene-butadiene rubber, synthetic polyisoprene rubber (IR), acrylonitrile-butadiene rubber, and natural rubber (NR) containing the same loading of a precipitated silica filler were prepared. The silica surface was pretreated with TESPT, which is a sulfur-bearing bifunctional organosilane to chemically bond silica to the rubber. The rubber compounds were subsequently cured by reacting the tetrasulfane groups of TESPT with double bonds in the rubber chains and the cure was optimized by adding sulfenamide accelerator and zinc oxide. The IR and NR needed more accelerators for curing. Surprisingly, there was no obvious correlation between the internal double bond content and the accelerator requirement for the optimum cure of the rubbers. Using the TESPT pretreated silanized silica was a very efficient method for cross-linking and reinforcing the rubbers. It reduced the use of the chemical curatives significantly while maintaining excellent mechanical properties of the cured rubbers. Moreover, it improved health and safety at work-place, reduced cost, and minimized damage to the environment because less chemical curatives were used. Therefore, TESPT was classified as "green silane" for use in rubber formulations

Conjugates of Degraded and Oxidized Hydroxyethyl Starch and Sulfonylureas: Synthesis, Characterization, and in Vivo Antidiabetic Activity

Orally administered drugs usually face the problem of low water solubility, low permeability, and less retention in bloodstream leading to unsatisfactory pharmacokinetic profile of drugs. Polymer conjugation has attracted increasing interest in the pharmaceutical industry for delivering such low molecular weight (<i>M</i>_w) drugs as well as some complex compounds. In the present work, degraded and oxidized hydroxyethyl starch (HES), a highly biocompatible semisynthetic biopolymer, was used as a drug carrier to overcome the solubility and permeability problems. The HES was coupled with synthesized <i>N</i>-arylsulfonylbenzimidazolones, a class of sulfonylurea derivatives, by creating an amide linkage between the two species. The coupled products were characterized using GPC, FT-IR, ¹H NMR, and ¹³C NMR spectroscopy. The experiments established the viability of covalent coupling between the biopolymer and <i>N</i>-arylsulfonylbenzimidazolones. The coupled products were screened for their in vivo antidiabetic potential on male albino rats. The coupling of sulfonylurea derivatives with HES resulted in a marked increase of the hypoglycemic activity of all the compounds. 2,3-Dihydro-3-(4-nitrobenzensulfonyl)-2-oxo-1<i>H</i>-benzimidazole coupled to HES₁₀₁₀₀ was found most potent with a 67% reduction in blood glucose level of the rats as compared to 41% reduction produced by tolbutamide and 38% by metformin

Curing rubber compounds efficiently and cost-effectively

Curing rubber compounds efficiently and cost-effectivel

(A) Western blot analysis of the NR2D subunit protein expression in neonatal and adult hippocampal tissue obtained from the WT and PrP-null mouse

α-Actin expression was used as a loading control. (B) NMDAR subunit surface expression as visualized by immunolabel reactivity with an antibody targeted against an extracellular (N terminus) epitope of NR2D. A punctate pattern of receptor distribution is visualized along dendritic processes. The depth of field is ∼1 μm. (C) Surface expression of NR2D relative to total cellular NR2D protein content as quantified using an ELISA assay in permeabilized (P) and nonpermeabilized (NP) cells. The number of neuronal culture samples is indicated in parentheses. Error bars represent SEM. (D) Coimmunoprecipitation of PrP and NR2D using both permutations of tag and probe showing that PrP and NR2D are in a complex. In the top panel, the blot was probed with a PrP antibody, and in the bottom panel, membrane was probed with NR2D antibody. The lane labeled control reflects beads without antibody. The experiment is a representative example of four different repetitions for both neonatal and adult mouse hippocampal tissue. (E) Western blot demonstrating the lack of coimmunoprecipitation between NR2B and PrP, whereas NR2B can be detected in brain homogenate (input). (F) Costaining of WT mouse hippocampal neurons for PrP (red) and NR2D (blue). The cells were not permeabilized, thus allowing for the selective staining of cell surface protein. The white line in the top left panel indicates the position of the linescan shown in the bottom left panel. The rectangle in the merged image (top right) corresponds to the magnified images shown at the bottom right. The arrowheads highlight examples of clear colocalization between NR2D and PrP. Bars: (B, top left) 7.5 μm; (B, top right and F, top) 10 μm; (B, bottom) 1 μm; (F, bottom) 2 μm.<p><b>Copyright information:</b></p><p>Taken from "Prion protein attenuates excitotoxicity by inhibiting NMDA receptors"</p><p></p><p>The Journal of Cell Biology 2008;181(3):551-565.</p><p>Published online 5 May 2008</p><p>PMCID:PMC2364707.</p><p></p

(A) Paired pulses evoked by stimulation of the Schaffer collaterals in slices from P30–45 mice in normal artificial cerebrospinal fluid (aCSF)

(B) Quantification of the number of population spikes in WT and PrP-null slices in aCSF. (C, top) Minimum stimulus intensity required to evoke a single population spike in WT and PrP-null slices. (middle) Stimulus intensity required to evoke maximum single population spike amplitude. (bottom) Extent of paired pulse facilitation in WT and PrP-null slices. (D, top) Field potentials recorded from PrP-null slices before and after the application of 50 μM APV as shown for P2. (bottom) Quantification of the number of population spikes before and after APV application in PrP-null slices. (E) Evoked field potentials recorded after 5 min of perfusion in zero-magnesium aCSF (ZM-aCSF). The gray arrows indicate successive population spikes, which are augmented in the PrP-null slices. (F, left) The number of population spikes overriding the fEPSP in slices exposed to ZM-aCSF. (second graph) Time to the observance of the first seizurelike discharge in ZM-aCSF. (third graph) Time to the occurrence of the first seizurelike event (SLE) upon perfusion with ZM-aCSF. (right) Duration of seizurelike events in WT and PrP-null slices. The black and gray arrowheads indicate the primary population spikes and the additional population spikes, respectively, overriding the fEPSP in each pulse (P1 and P2); these latter polyspikes were only observed in PrP-null mice. Data are represented as mean ± SEM (error bars) with statistical significance denoted as *, P < 0.05 and **, P < 0.001. Numbers in parentheses indicate the number of slices.<p><b>Copyright information:</b></p><p>Taken from "Prion protein attenuates excitotoxicity by inhibiting NMDA receptors"</p><p></p><p>The Journal of Cell Biology 2008;181(3):551-565.</p><p>Published online 5 May 2008</p><p>PMCID:PMC2364707.</p><p></p

(A) Light microscope images of neuronal cultures after 20 min of exposure to 0

3, 0.6, and 1.0 mM NMDA followed by 24-h recovery. Cells were stained with trypan blue (dark blue) and TUNEL (brown); methyl green was used as the counterstain. (B) Mean cell counts for trypan blue– and TUNEL-stained cells in WT and PrP-null cultures. (C) Light microscope images showing TUNEL-stained neurons from PrP-null mice in the presence of NMDA and NMDA + APV. (D) Percentage of TUNEL-positive neurons from PrP-null mice in response to NMDA and NMDA + APV. The drug concentrations were 1 mM NMDA and 100 μM APV. Data are represented as mean ± SEM (error bars), with statistical significance denoted as *, P < 0.05 and **, P < 0.001. Data were obtained from four culture rounds, and six random fields were imaged per condition. Bar, 100 μm.<p><b>Copyright information:</b></p><p>Taken from "Prion protein attenuates excitotoxicity by inhibiting NMDA receptors"</p><p></p><p>The Journal of Cell Biology 2008;181(3):551-565.</p><p>Published online 5 May 2008</p><p>PMCID:PMC2364707.</p><p></p

(A) Fluoro-Jade labeling of neuronal bodies and processes in hippocampal sections in response to injection of vehicle (left) or NMDA (10-nmol equivalent; right)

(B) Quantification of lesion size relative to the hippocampus over a series of three to six sections per animal ( = 5 per experimental group). Data are represented as mean ± SEM (error bars), with statistical significance denoted as **, P < 0.001. Bar, 200 μm.<p><b>Copyright information:</b></p><p>Taken from "Prion protein attenuates excitotoxicity by inhibiting NMDA receptors"</p><p></p><p>The Journal of Cell Biology 2008;181(3):551-565.</p><p>Published online 5 May 2008</p><p>PMCID:PMC2364707.</p><p></p

(A) Representative examples of raw mEPSCs recorded in mature (12–16 DIV) WT and PrP-null hippocampal neurons in culture

In PrP-null neurons, NMDA-mediated mEPSCs were observed to be larger and showed prolonged decay times. (B) Event histograms for mEPSC amplitude (top) and decay time (bottom). Note that mEPSCs in PrP-null neurons exhibit a shift toward larger amplitude events and increased decay time constants. (C) Cumulative probability plots for mEPSC amplitude and decay times showing a shift in each summed distribution toward larger events with longer decay times (P < 0.05; Kolmogorov-Smirnov test). (D) Mean values for mEPSC waveform parameters showing increased EPSC amplitudes and prolonged decay times. Here, decay time refers to the time required for an e-fold reduction in peak current amplitude. Data are represented as mean ± SEM (error bars), with statistical significance denoted as *, P < 0.05 and **, P < 0.001. Numbers in parentheses indicate the number of cells.<p><b>Copyright information:</b></p><p>Taken from "Prion protein attenuates excitotoxicity by inhibiting NMDA receptors"</p><p></p><p>The Journal of Cell Biology 2008;181(3):551-565.</p><p>Published online 5 May 2008</p><p>PMCID:PMC2364707.</p><p></p