A new test for cleaning efficiency assessment of cleaners for hard surfaces

A new test was developed to assess the efficiency of no-wiping hard-surface cleaning. The test allows cleaner comparisons according to their ability to remove greasy soils. The chosen approach minimizes the mechanical forces applied while cleaning so that the interactions between a detergent solution and the soil to be removed can be characterized. For this, immersion cleaning was chosen, with coated stainless steel as substrate and pigmented oils as the model soil. Several parameters were studied in defined ranges using the Experimental Design method and systematic comparisons. The test shows high reliability on degreasing assessments and is there-fore especially suited to optimization of nonionic surfactant mixes. The originality of the test lies in the possibility of keeping a visual trace of the cleaned substrate appearance by imprinting it on a piece of paper. The validation of the test leads to corroboration of several practical observations. Temperature and agitation play a major role in cleaning efficiency. Detergent solution concentration is a more relevant parameter than pH. Sodium carbonate is shown to have a higher buffering effect than pentahydrated sodium metasilicate. The test is easy to set up, highly sensitive, and can be adapted to solve the problems encountered by formulators of detergent cleaners, such as screening the best ethoxylated fatty alcohol mix for better degreasing properties.     

Myo-InositolTrisPyroPhosphate treatment leads to HIF-1α suppression and eradication of early hepatoma tumors in rats

Myo-inositol trispyrophosphate (ITPP), a synthetic allosteric effector of hemoglobin, increases the regulated oxygen-releasing capacity of red blood cells (RBCs), leading to suppression of hypoxia-inducible factor 1α (HIF-1α) and to down-regulation of hypoxia-inducible genes such as vascular endothelial growth factor (VEGF). As a consequence, tumor growth is markedly affected. The effect of weekly intravenous injection of ITPP on an orthotopic, syngenic rat hepatocellular carcinoma (HCC) model was compared to that for untreated animals and animals subjected to conventional Doxorubicin chemotherapy. The longitudinal examination of HCC was performed by microCT imaging, and the cellular and molecular changes were evaluated by histology and Western blotting analysis of HIF-1α, VEGF, and caspase-3 gene expression in the tumor and in the surrounding liver. Hematologic impact was evaluated by blood cell-count measurement and determination of P50 (oxygen partial pressure for a 50 % oxygen saturation of hemoglobin). The HCC evaluation by microCT revealed a high potency of ITPP for tumor growth inhibition, thus allowing long-term survival and even cure of almost all the treated animals. The P50 value of hemoglobin in RBCs underwent a shift of 30 % following ITPP injection. Under these conditions, HIF-1α activity was strongly decreased, VEGF expression was down-regulated, and apoptosis was induced in HCC and surrounding liver cells, as indicated by Caspase-3 expression. ITPP did not affect hematologic parameters during treatment. The observations of in vivo tumor eradication suggest a significant clinical potential for ITPP in cancer therapy.     

Plasmonic propagations distances for interferometric surface plasmon resonance biosensing

A surface plasmon resonance (SPR) scheme is proposed in which the local phase modulations of the coupled plasmons can interfere and yield phase-sensitive intensity modulations in the measured signal. The result is an increased traceability of the SPR shifts for biosensing applications. The main system limitation is the propagation distance of the coupled plasmon modes. This aspect is therefore studied for thin film microstructures operating in the visible and near-infrared spectral regions. The surface roughness of the substrate layer is examined for different dielectrics and deposition methods. The Au layer, on which the plasmonic modes are propagating and the biosensing occurs, is also examined. The surface roughness and dielectric values for various deposition rates of very thin Au films are measured. We also investigate an interferometric SPR setup where, due to the power flux transfer between plasmon modes, the specific choice of grating coupler can either decrease or increase the plasmon propagation length.     

Fullerene-functionalized carbon nanotubes as improved optical limiting devices

We report the synthesis, characterization and optical limiting behavior of a nanohybrid built by grafting C₆₀-fullerenes on carbon nanotubes (CNTs). The nonlinear optical limiting properties of the CNT-C₆₀ complex were investigated at wavelengths where C₆₀ does not absorb. We found that the nanohybrid had superior performances to those of CNTs and fullerenes, either taken individually or as a mixture. This enhanced optical limitation of the nanohybrid suggests not only cooperative but also synergistic effects between the two carbon forms. A mechanism involving higher excitonic states of the CNTs formed by Auger recombination of low energy excitons is proposed.     

Chemometric Characterization of Eight Monovarietal Algerian Virgin Olive Oils

Differences in triacylglycerol, fatty acid, squalene, and tocopherol compositions were demonstrated between 8 varieties of virgin olive oils (Aberkane, Aguenaou, Aharoun, Aimel, Bouchouk Guergour, Bouichret, Chemlal, and Sigoise) from Petite Kabylie area, north eastern Algeria. Fatty acid and triacylglycerol morphotypes characterized each variety. A principal component analysis, based on triacylglycerol, fatty acid, and squalene compositions, differentiates between varieties. Minor fatty acids and squalene, usually not taken into account individually in authentication studies, are strongly involved in this differentiation, whereas the discriminant power of tocopherols is weak. Soft Independent Modeling of Class Analogy classification using chemical compositions as variables showed a high potential to authenticate the varietal origin of Algerian virgin olive oils.     

Effect of processing procedures and conditions on structural,morphological, and rheological properties of polyethylene/polyamide/nanoclay blends

The article deals with the effect of processing procedures and conditions on structural, morphological, and rheological properties of ternary blends composed of polyethylene (PE), polyamide (PA)‐12, and organically modified montmorillonite nanoclay with selective affinity. Samples were prepared from PE/PA and PA/PE blends, either by simultaneous mixing or from a polymer/clay masterbatch, using two processing conditions. The results have shown the existence of a weight fraction threshold, above which no significant processing effect was observed. Below this weight fraction threshold, the results tend to underline the significant role of two parameters that depend on processing procedures and/or conditions: the contact time between PE and PA phases and the contact time between clay and PA. Clay structure, blend morphology, and rheological properties were all shown to depend on these two parameters, and also on the nature of the matrix (PE or PA), because of the selective affinity of clay toward polymer phases. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers     

Thermodynamic investigation of thermoresponsive xanthan‐poly (N‐isopropylacrylamide) hydrogels

Polysaccharide‐based hydrogels, such as xanthan maleate/poly(N‐isopropylacrylamide) (PNIPAAm) interpenetrated polymer networks, are thermostimulable materials of interest for the controlled release of biologically active components due to conformation changes at the low critical‐solution temperature (LCST) PNIPAAm phase transition. The phase transition of these interpenetrated polymer network hydrogels, where PNIPAAm is in a ‘confined’ environment, was examined by high resolution magic angle spinning nuclear magnetic resonance and differential scanning calorimetry. High resolution magic angle spinning nuclear magnetic resonance spectroscopy allows the accurate determination of LCST and an evaluation of the corresponding thermodynamic data. More particularly, the evolution of these data as a function of the composition of the hydrogel, and of the external parameters such as pH and ionic strength, was considered. LCST shows a minimal value with increasing xanthan content. Moreover, it was possible to calculate, as a function of temperature, the fraction of NIPAAm which remains uncollapsed. The data obtained for pure PNIPAAm hydrogels are in good agreement with recently published results. The phase transition of PNIPAAm in a diphasic hydrogel is broader when PNIPAAm is ‘confined’ within an interpenetrated polymer network than in a pure PNIPAAm crosslinked network. The widening of the transition with increasing xanthan content indicates a reduction of the PNIPAAm interchain aggregation in a network structure. Copyright © 2011 Society of Chemical Industry     

Role of Serum Cholesterol and Statin Use in the Risk of Prostate Cancer Detection and Tumor Aggressiveness

The aim of this study was to analyze the relationship between statin use along with serum cholesterol levels and prostate cancer (PCa) detection and aggressiveness. Statin users of three years or more and serum cholesterol levels (SC) were assessed in 2408 men scheduled for prostate biopsy. SC was classified as normal (NSC: <200 mg/dL) or high (HSC: >200 mg/dL). High-grade PCa (HGPCa) was considered if the Gleason score was greater than 7. Statin users comprised 30.9% of those studied. The PCa detection rate was 31.2% of men on statins and 37% of non-statin users (p < 0.006). The PCa detection rate was 26.3% in men with NSC and 40.6% in those with HSC (p < 0.001). In the subset of NSC men, the PCa rate was 26.5% for statin users and 26.2% for non-users (p = 0.939), while in men with HSC, the PCa rate was 36.4% for statin users and 42.0% for non-statin users (p = 0.063). The HGPCa rate was 41.8% for statin users and 32.5% for non-users (p = 0.012). NSC men had a 53.8% rate of HGPCa, while the rate was only 27.6% in HSC men (p < 0.001). NSC men on statins had an HGPCa rate of 70.2%, while non-statin users had a rate of 41.2% (p < 0.001). The HGPCa rate for HSC men on statins was 18.8%, while the rate was 30.0% (p = 0.011) for non-users. Logistic regression analysis suggested that serum cholesterol levels could serve as an independent predictor of PCa risk, OR 1.87 (95% CI 1.56–2.24) and HGPCa risk, OR 0.31 (95% CI 0.23–0.44), while statin usage could not. Statin treatment may prevent PCa detection through serum cholesterol-mediated mechanisms. A disturbing increase in the HGPCa rate was observed in statin users who normalized their serum cholesterol.     

Extensive N‐methylation of chitosan: evaluating the effects of the reaction conditions by using response surface methodology

The effects of reaction time, concentration of aqueous sodium hydroxide and molar ratio iodomethane/chitosan on the yield of the reaction of chitosan with iodomethane in N‐methyl‐2‐pyrrolidone (NMP) at 25.0 ± 0.1 °C, as well as on the characteristics of the resulting N,N,N‐trimethylchitosan (TMCh), were evaluated by using full‐factorial 2³ design analysis and response surface methodology. This study also aimed to determine the reaction conditions allowing the production of water‐soluble TMCh presenting a high average degree of quaternization and intrinsic viscosity at high reaction yield. ¹H NMR spectroscopy was employed for structural characterization, including the determination of average degrees of acetylation () and quaternization (), while capillary viscometry was used to determine intrinsic viscosity [η]. The results show that when the extensive N‐methylation is carried out for 24 h in NMP/15% NaOH (w/v) employing a lower excess of iodomethane (CH₃I/Ch = 9), water‐soluble highly substituted ( = 46.0%) TMCh ([η] = 213.0 mL g^?1) can be produced in high yield (81.8%). The highly significant mathematical models resulting from this study describe the dependence of the experimental responses on the reaction conditions and allow the characteristics and properties of the resulting TMCh to be defined by properly choosing the reaction conditions. © 2015 Society of Chemical Industry     

Thiol-ene “clickable” carbon-chain polymers based on diallyl cyclopropane-1,1-dicarboxylate

A novel type of clickable polymers with a very high local density of allyl side groups was developed. These polymers were obtained by the anionic ring-opening (co)polymerization of diallyl cyclopropane-1,1-dicarboxylate using as an initiating system a protic precursor whose acid–base reaction with the t-BuP₄ phosphazene base generated the initiator in situ. The obtained polymers display geminated allyl groups on every third carbon alongside the macromolecular backbone. Homopolymers as well as block and statistical copolymers have been synthesized, with controlled molecular weights and narrow molecular weight distributions. The coupling of mercaptans with the allyl CC double bonds has been investigated both thermally and photochemically, with the influence of the type of initiation on the efficiency of the polymer modification being discussed in comparison with other “clickable” systems. Further functionalization by several thiols was performed, leading to a range of functional poly(cyclopropane-1,1-dicarboxylate)s.