Acetals as nucleating agents for polypropylene

Nucleating agents increase the impact strength, tensile strength, and tensile elasticity modulus of semicrystalline polymers. Nucleating agents also decrease product cycle times, resulting in a cost savings per product unit. We have synthesized and tested 15 compounds as nucleactors for polypropylene. Of these, trinapthylidene sorbitol, tri-(4-methyl-1-naphthylidene)sorbitol, tri-(4-methoxy-1-naphthylidene) sorbitol, and dibenzylidene xylitol are efficient nucleators of polypropylene. Trinaphthylidene sorbitol (tns) has two major diastereomers: The “S” diastereomer yields a faster crystallization rate for polypropylene than does the commercial nucleator dibenzylidene sorbitol (Millad 3905). Crystallization rates are 208 and 88, respectively (t min^?1 × 1000). The “R” diastereomer, however, is a poor nucleator and interferes with the nucleating activity of the “S” diastereomer. A 52/48 mixture of diastereomers does not nucleate polypropylene, even at twice the concentration. This is first time that the importance of stereochemistry has been demonstrated in the nucleating action. © 1994 John Wiley & Sons, Inc.     

High rate nitrogen removal in an alum sludge-based intermittent aeration constructed wetland

A new development on treatment wetland technology for the purpose of achieving high rate nitrogen removal from high strength wastewater has been made in this study. The laboratory scale alum sludge-based intermittent aeration constructed wetland (AlS-IACW) was integrated with predenitrification, intermittent aeration, and step-feeding strategies. Results obtained from 280 days of operation have demonstrated extraordinary nitrogen removal performance with mean total nitrogen (TN) removal efficiency of 90% under high N loading rate (NLR) of 46.7 g N m(-2) d(-1). This performance was a substantial improvement compared to the reported TN removal performance in literature. Most significantly, partial nitrification and simultaneous nitrification denitrification (SND) via nitrite was found to be the main nitrogen conversion pathways in the AlS-IACW system under high dissolved oxygen concentrations (3-6 mg L(-1)) without specific control. SND under high dissolved oxygen (DO) brings high nitrogen conversion rates. Partial nitrification and SND via nitrite can significantly reduce the demand for organic carbon compared with full nitrification and denitrification via nitrate (up to 40%). Overall, these mechanisms allow the system to maintaining efficient and high rate TN removal even under carbon limiting conditions.     

Development of male contraceptive vaccine--a perspective

Anti-disialoganglioside (GD2) monoclonal antibodies (MAbs) have been used in vivo for immunolocalization and in phase I and II trials to target disseminated neuroblastoma, the most common extracranial solid tumor in children. However, the efficacy of these first-generation MAbs is likely to be improved by using engineered anti-GD2 antibodies. The generation of single-chain antibody fragments (scFv) could be very helpful as these molecules can be further modified to produce recombinant molecules with pre-defined properties such as immunotoxins, chimeric, or bispecific antibodies. Thus, a scFv directed against GD2 (scFv 7A4) was cloned, sequenced, and expressed. Its binding properties were characterized and compared to that of the parental MAb 7A4. Nucleotide sequence analysis of the scFv 7A4 indicated that its VH region belongs to the V region IIID subgroup and the V kappa to the V region II subgroup. The scFv 7A4 bound to GD2+ neuroblastoma cell lines but not to GD2- cell lines or to GD2- cells isolated from peripheral blood. ELISA and thin-layer chromatography (TLC) indicated that it retained the anti-GD2 specificity, and exhibited a slight cross-reaction with GD3 as the parental MAb. This scFv makes it possible to develop new useful reagents through genetic engineering for adjuvant tumor therapy.     

The thiazide-sensitive Na-Cl cotransporter is an aldosterone-induced protein

Although the collecting duct is regarded as the primary site at which mineralocorticoids regulate renal sodium transport in the kidney, recent evidence points to the distal convoluted tubule as a possible site of mineralocorticoid action. To investigate whether mineralocorticoids regulate the expression of the thiazide-sensitive Na-Cl cotransporter (TSC), the chief apical sodium entry pathway of distal convoluted tubule cells, we prepared an affinity-purified, peptide-directed antibody to TSC. On immunoblots, the antibody recognized a prominent 165-kDa band in membrane fractions from the renal cortex but not from the renal medulla. Immunofluorescence immunocytochemistry showed TSC labeling only in distal convoluted tubule cells. Semiquantitative immunoblotting studies demonstrated a large increase in TSC expression in the renal cortex of rats on a low-NaCl diet (207 +/- 21% of control diet). Immunofluorescence localization in tissue sections confirmed the strong increase in TSC expression. Treatment of rats for 10 days with a continuous subcutaneous infusion of aldosterone also increased TSC expression (380 +/- 58% of controls). Furthermore, 7-day treatment of rats with an orally administered mineralocorticoid, fludrocortisone, increased TSC expression (656 +/- 114% of controls). We conclude that the distal convoluted tubule is an important site of action of the mineralocorticoid aldosterone, which strongly up-regulates the expression of TSC.     

Rind of the rambutan, Nephelium lappaceum, a potential source of natural antioxidants

The rind of rambutan, which is normally discarded was found to contain extremely high antioxidant activity when assessed using several methods. Although having a yield of only 18%, the ethanolic rambutan rind extract had a total phenolic content of 762 ± 10 mg GAE/g extract, which is comparable to that of a commercial preparation of grape seed extract. Comparing the extract’s pro-oxidant capabilities with vitamin C, α-tocopherol, grape seed and green tea, the rind had the lowest pro-oxidant capacity. In addition, the extract at 100 μg/ml was seen to limit oxidant-induced cell death (DPPH at 50 μM) by apoptosis to an extent similar to that of grape seed. The extracts were not cytotoxic to normal mouse fibroblast cells or splenocytes while the powderised rind was seen to have heavy metals contents far below the permissible levels for nutraceuticals. Our study for the first time reveals the high phenolic content, low pro-oxidant capacity and strong antioxidant activity of the extract from rind of Nephelium lappaceum. This extract, either alone or in combination with other active principles, can be used in cosmetic, nutraceutical and pharmaceutical applications.     

Hydrolysis of SnCl2 on polyaniline: Formation of conducting PAni‐SnO2 composite with enhanced electrochemical properties

First time in the literature, we report that polyaniline‐EB can be doped by SnCl₂ to give conducting SnO₂ doped polyaniline novel material. The composite is characterized by Fourier transform infrared, ultraviolet‐visible, X‐ray diffraction, scanning electron micrograph, transmission electron microscopy, and electrochemical methods. The new composite exhibited improved electrochemical properties compared with the virgin polymer. The composite is also expected for its high sensitivity for recognizing volatile organic compounds. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

The importance of fatty acids in glycaemic response

Most diets worldwide are composed of high carbohydrate foods. Their consumption is associated with a rapid rise in blood glucose. The potential role that the degree of saturation of fatty acids may have in glycaemic response forms the basis of this paper. The addition of butter, olive oil or grapeseed oil significantly reduced the glycaemic index of white bread (white bread GI = 71; bread + butter GI = 53, bread + grapeseed oil GI = 58; bread+ olive oil GI = 50. The addition of olive oil had the greatest impact on GI. Olive oil has been widely recommended for its impact on blood lipids and cholesterol. Olive oil's influence on glycaemic response spawns a new line of research that should examine the role of lipids in carbohydrate metabolism.     

No-reference image contrast measure using image statistics and random forest

Multimedia Tools and Applications - Image quality assessment is very crucial for certain image processing applications. Images can be distorted from multiple sources like a fault in sensors, camera...     

Laser from the dimer state of a conjugated polymer (PFO) in solution

The spectral and laser properties of the conjugated polymer poly (9,9-dioctylfluorenyl-2, 7-diyl) (PFO) in benzene have been studied and presented in this paper. The absorption spectra of PFO in benzene under low concentration showed that there was only one peak at 390 nm. When the concentration was increased, a new peak at 437 nm appeared additionally, indicating dimer formation at higher concentration of PFO in benzene. The fluorescence spectra for low concentration showed two peaks at 422 nm and 444 nm, which could be attributed to the monomer and the excimer. At the longer wavelength side of these spectra, there was a hump at 465 nm. This hump became dominant for higher concentrations and in low temperatures, while the other peaks became weaker. So, this new peak at 465 nm may be due to the dimer. For still higher concentrations, the peaks at 422 nm and 444 nm vanished and there was a dominant peak only at 465 nm. Under suitable concentration and pump power excitation of Nd: YAG laser (355 nm) the amplified spontaneous emission (ASE) spectra were obtained. It could be seen that there were three ASE peaks at 422, 444 and 470 nm. These peaks could be attributed to the monomer, excimer and dimer respectively. This is perhaps the first report on ASE from dimers of the conjugated polymer, PFO in liquid solution.