Synthesis and characterization of bubble wrap-like hollow barium silicate–carbonate nanospheres for the epoxidation of styrene

Novel porous bubble wrap-like hollow barium silicate–carbonate nanospheres were successfully prepared at a barium/CTAB molar ratio of 0.75 and 1.00. The average pore size, BET surface area and total pore volume of the most catalytically active catalyst in the epoxidation of styrene, 1.00BaMST were 5.0 nm, 42 m2 g−1 and 0.0771 cm3 g−1, respectively. The styrene epoxidation reaction was carried out using H2O2 as an oxidant. Barium silicate and carbonate groups detected on the catalyst’s surface are proposed to activate the H2O2 and selectively oxidize the styrene to styrene oxide. The 1.00BaMST achieved 63.3% of styrene conversion and 77.8% of epoxide selectivity at mild conditions (3 h, 60 ◦C). The reaction energy barrier was calculated to be 17.3 kJ mol−1

Sustainable green poly(lactic acid) (PLA)/eggshell powder (ESP) biocomposites

Poly(lactic acid), which is most commonly referred to by its acronym PLA, is a polymer that may be recycled and naturally deteriorated. It is also inherently fragile and has a low impact strength. PLA, when mixed with eggshells powder, can produce a PLA/ESP composites. The purpose of this study was to investigate the physical characteristics of PLA composites that contained ESP or calcium carbonate (CaCO3). Extrusion melt mixing in a twin-screw extruder was used in conjunction with PLA with different ESP concentrations to develop this eco-friendly and sustainable nanocomposite material. The blended compounds were allowed to reach room temperature before being formed into thin films with dimensions of 20 mm in width, 100 mm in length, and 5 mm in thickness. These films were put through a series of tests to determine their mechanical, thermal, and chemical properties. Tests including stress-strain properties, FTIR, thermogravimetric analysis (TGA), and scanning electron microscopy were performed on the films (SEM)

Poly(lactic acid)/acrylonitrile butadiene styrene nanocomposites with hybrid graphene nanoplatelet/organomontmorillonite: effect of processing temperatures

This work reports the preparation and characterization of poly(lactic) acid/acrylonitrile butadiene styrene/graphene nanoplatelets/Cloisite C20A montmorillonite (PLA/ABS/GnP/C20A) nanocomposites via melt blending. The clay is hybridized with graphene to increase its dispersion in the polymer matrix. The melt processing temperatures play a vital role in the properties of the resulting nanocomposites in dictating the extent of thermal stability and dispersion of the fillers. The hybrid nanocomposites were characterized for stress-strain, thermal, chemical, and morphological properties. The findings were that there was an increase in the mechanical properties in terms of tensile strength and Young’s modulus with the PLA/ABS/GnP/C20A at the high-temperature profile having the highest values of 43.1 MPa and 2533 MPa. The elongation at break increases slightly, due to the brittle properties of GnP. It was found that the dispersion of the fillers increased with increasing temperature profiles, as revealed by the morphological analysis by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The void size was also observed to be smaller and more homogenous with increasing temperature. However, in terms of thermal degradation analysis, the addition of fillers increases its thermal stability as the decomposition onset temperature increases by 22.58C

Mechanical and thermal properties of binary blends poly lactic acid (PLA) and recycled high-density polyethylene (rHDPE)

In this work, plastic bottles made of high-density polyethene (HDPE) have been recycled and blended with poly(lactic acid) (PLA). The aim of the work is to prepare a binary blend of PLA and Recycled HDPE (rHDPE) at 90:10 blend ratio by using a twin-screw extruder. The blends were compression moulded and characterized in terms of mechanical and thermal properties. It was found that the rHDPE increased the tensile modulus of the binary blend. Fracture morphology demonstrated that the blend of rHDPE and PLA is immiscible. In terms of thermal property, as measured by Differential Scanning Calorimetry (DSC), the glass transition temperature of the binary blend showed a lower value, whereas the crystallization process was significantly improved

Second international congress on immunopharmacology : delivery systems and current strategies for drug design

The 2nd International Congress on Immunopharmacology was held in June of 2011 at the Conference Center of Plaza America in Varadero, Cuba. The main goal of this meeting was to provide state-of-the-art communications for scientists, manufacturers, regulators and healthcare workers, to accelerate progress in the development of biological and biotechnological products and to promote exchange/scientific cooperation between researchers. 300 delegates from 22 countries attended the conference. The wide-ranging programme commenced with a plenary session and then split into a series of parallel workshops and symposia, covering “Advances in Immunopharmacology”, “Neuroimmunology”, “Therapeutic Biological Products”, “Prophylaxis and Treatment of Helicobacter pylori”, “Pharmacology of Cytochrome P450”, “Hereditary Ataxias” and “Delivery Systems and Current Strategies for Drug Design”. In this last Symposium, a substantial body of data was presented relating to the development of delivery systems with adjuvant and vaccine potential and also to strategies focused in therapeutic and prophylactic approaches against tuberculosis. This issue is dedicated to some of the results presented in this area

Anticancer activity of a sub-fraction of dichloromethane extract of Strobilanthes crispus on human breast and prostate cancer cells in vitro

<p>Abstract</p> <p>Background</p> <p>The leaves of <it>Strobilanthes crispus </it>(<it>S. crispus</it>) which is native to the regions of Madagascar to the Malay Archipelago, are used in folk medicine for their antidiabetic, diuretic, anticancer and blood pressure lowering properties. Crude extracts of this plant have been found to be cytotoxic to human cancer cell lines and protective against chemically-induced hepatocarcinogenesis in rats. In this study, the cytotoxicity of various sub-fractions of dichloromethane extract isolated from the leaves of <it>S. crispus </it>was determined and the anticancer activity of one of the bioactive sub-fractions, SC/D-F9, was further analysed in breast and prostate cancer cell lines.</p> <p>Methods</p> <p>The dichloromethane extract of <it>S. crispus </it>was chromatographed on silica gel by flash column chromatography. The ability of the various sub-fractions obtained to induce cell death of MCF-7, MDA-MB-231, PC-3 and DU-145 cell lines was determined using the LDH assay. The dose-response effect and the EC₅₀values of the active sub-fraction, SC/D-F9, were determined. Apoptosis was detected using Annexin V antibody and propidium iodide staining and analysed by fluorescence microscopy and flow cytometry, while caspase 3/7 activity was detected using FLICA caspase inhibitor and analysed by fluorescence microscopy.</p> <p>Results</p> <p>Selected sub-fractions of the dichloromethane extract induced death of MCF-7, MDA-MB-231, PC-3 and DU-145 cells. The sub-fraction SC/D-F9, consistently killed breast and prostate cancer cell lines with low EC₅₀values but is non-cytotoxic to the normal breast epithelial cell line, MCF-10A. SC/D-F9 displayed relatively higher cytotoxicity compared to tamoxifen, paclitaxel, docetaxel and doxorubicin. Cell death induced by SC/D-F9 occurred via apoptosis with the involvement of caspase 3 and/or 7.</p> <p>Conclusions</p> <p>A dichloromethane sub-fraction of <it>S. crispus </it>displayed potent anticancer activities <it>in vitro </it>that can be further exploited for the development of a potential therapeutic anticancer agent.</p

Bilirubin Sensing and a Cross Sensitivity Evaluation with Co2 and O2 Using Optical Fiber Sensor

This paper describes an optical fiber sensor for the monitoring of bilirubin concentration and commonly called jaundice. An open path optical technique is used to analyze the absorption lines of bilirubin within the Ultra Violet/ Visible region. By using a wavelength corresponding to a bilirubin absorption peak, the Beer-Lambert Law can be used to relate the concentration of bilirubin surrounding the sensing portion to the amount of absorbed light. In the initial experiment, the absorption cross section for MAS bilirubin a product from Thermo Scientific was investigated and compare with theoretical data. an empty cuvette was used to measure incident intensity when the light passes through the empty cuvette. Then a cuvette was filled with bilirubin sample before measured the transmitted intensity. The theoretical absorbance of bilirubin shows maximum absorption in the range of 400 nm to 500 nm. The experimental result shows the absorption line for measured MAS bilirubin is in similar pattern and the maximum absorbance shows in range 400 nm to 500 nm. Cross sensitivity evaluation would be carried out to study the cross sensitivity of bilirubin absoprtion spectrum with other human blood molecules like oxygen (O2) and carbon dioxide (CO2) to yield the best wavelength for the absorption