Polyurethanes from benzene polyols synthesized from vegetable oils: Dependence of physical properties on structure

Asymmetric and symmetric aromatic triol isomers were synthesized from erucic acid. The pure asymmetric and symmetric triols were crosslinked with MDI into their corresponding polyurethane sheets. The physico‐chemical properties of these polyurethanes were studied by Fourier transform infrared (FTIR) spectroscopy, X‐ray diffraction (XRD), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), thermogravimetric analysis coupled with Fourier transform infrared (TGA‐FTIR) spectroscopy, and tensile analysis. The A‐PU and S‐PU demonstrated differences in their glass transition temperatures (T_g) and crosslinking densities. The difference in T_g of these polyurethanes could be explained by the differences in crosslinking densities, which could be related to the increase in steric hindrance, to the crosslinking MDI molecules, between adjacent hydroxyl groups of the asymmetric triol monomers. Overall, it was found that both polyurethanes had similar mechanical and thermal properties. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Nanochannel-based single molecule recycling

We present a method for measuring the fluorescence from a single molecule hundreds of times without surface immobilization. The approach is based on the use of electroosmosis to repeatedly drive a single target molecule in a fused silica nanochannel through a stationary laser focus. Single molecule fluorescence detected during the transit time through the laser focus is used to repeatedly reverse the electrical potential controlling the flow direction. Our method does not rely on continuous observation and therefore is less susceptible to fluorescence blinking than existing fluorescence-based trapping schemes. The variation in the turnaround times can be used to measure the diffusion coefficient on a single molecule level. We demonstrate the ability to recycle both proteins and DNA in nanochannels and show that the procedure can be combined with single-pair F?rster energy transfer. Nanochannel-based single molecule recycling holds promise for studying conformational dynamics on the same single molecule in solution and without surface tethering.     

In-depth material characterization of polyhydroxybutyrate from a forest biorefinery

Large-scale replacement of petroplastics with compostable plastics, like polyhydroxybutyrates (PHB) will contribute to elimination plastic pollution, decrease greenhouse gas emissions, and valorize local biomass resources. Lignocellulose hydrolysates have emerged as potentially sustainable carbon sources for PHB production. For industrial processing, it is necessary to know the polymer properties. Yet, most studies on PHB samples from lignocellulose report few material properties. PHB samples produced from a pilot scale hardwood holocellulose hydrolysate conversion process were characterized and compared with PHB from a sugar hydrolysate and a commercial PHB powder. PHB from hardwood holocellulose hydrolysate was found to be comparable with commercial PHB in all properties. Differential scanning calorimetry and thermal gravimetric analysis showed that all samples had similar thermal behavior, where the melting temperature was 176°C and the decomposition temperature was 293°C. From the melting enthalpy, all samples showed 63% crystallinity. Dynamic mechanical analysis showed a glass transition temperature at 5°C and a crystallization temperature of 57°C. Fourier transform infrared spectroscopy and nuclear magnetic resonance confirmed that the samples were homopolymers comprised of hydroxybutyrate units. The difference among the samples was the number average molecular mass, being lower for wood hydrolysate (246.4 kDa) than sugar hydrolysate (670.3 kDa).     

Direct estimation of residence time from input and output data

Residence time is a well known and widely used concept in the process industry, and its estimation is often needed to model or optimise a process. This study will demonstrate a new method using suitable measures of input and output data. There are two distinct characteristics of this method: it is not necessary to estimate the residence time from an explicit model, and the constraints on the excitation of the input signal are not as restrictive as common methods. © 2011 Canadian Society for Chemical Engineering     

Dynamic simulation and control of a paper machine wet end

A good simulation model for paper machines can be used to identify deficiencies in the design, bottlenecks during operation, and regions of poor control. It also allows users to test their hypotheses and innovations without potentially causing major upsets and reducing throughput. In this work, a dynamic model of the wet end system has been developed using the IDEAS^TM platform, describing the distribution of fines, fillers and fibres throughout the system. The model was then tested at steady state with mill data for the low‐ash and high‐ash production grades, and the results show that over 70% of the predicted values had only 5% deviation. The dynamic simulation was also used to show that the retention aid controller would react in the wrong direction due to changes in the wire pit consistency and the stock ratio would cause major changes in stream compositions and consistencies of the wet end.     

The real relationship: Schemas, stereotypes, and personal history.

A critique of the conventional view of "real" and transferential relationships in psychotherapy is presented. Semantic labels for fuzzy sets contribute to the confusion between what is experienced by therapists vis-á-vis clients. That analogous countertransferential processes occur in therapy in both therapists and clients is proposed, and a line of argument is presented to support this position. A symmetrical model of client-therapist interactions is proposed that affirms that both client and therapist infuse biasing schemas into the therapeutic process. The authors conclude that the real relationship is the so-called transferential relationship, which springs from the personal histories of both therapist and client. This principle enables clinical programs to prepare trainees to accommodate the inevitable dissonances that will be experienced by disparate and cross-cultural participants in this field. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Use of the Differential Ability Scales for children with attention-deficit/hyperactivity disorder.

The validity of the Differential Ability Scales (DAS) was assessed among children with attention-deficit/hyperactivity disorder (ADHD) and a matched control sample. The sample included 45 children with ADHD (69% with comorbidity) and 45 controls matched by age, gender, ethnicity, and parental educational level. Multivariate analysis of variance univariate test results and d ratios yielded statistically and clinically significant group differences on the Recall of Digits and Recall of Objects-Immediate diagnostic subtests. Discriminant function analyses indicated that the three Diagnostic Subtests accurately classified 67% of the sample with 69% correctly identified as controls and 64% correctly identified as ADHD. Recall of Digits was found to make the most significant contribution overall to the discriminant function. At a cutoff score of 40, Recall of Digits yielded high specificity and low sensitivity and moderate positive predictive power. Implications of results are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Two new lipoaminoacids with complementary modes of action: new prospects to fight out against skin aging

The mode of action of two cosmetic active ingredients (AIs), palmitoyl glycine (PG) and cocoyl alanine (CA) was studied with cDNA array experiments and quantitative PCR confirmations, which were performed on experimentally aged human fibroblasts. These preliminary studies revealed complementary profiles. Thus, specific supplementary investigations were then carried out for each AI. Protocols used were based either on in vitro models: (i) biochemical assays, (ii) monolayer cell culture (primary human fibroblasts and keratinocytes) and (iii) the model of capillary-like tube formation by human endothelial cells or on ex vivo models, i.e. topically treated skin explants and both immunohistochemical and Chromameter^TM investigations. New prospects are proposed to fight out against skin aging. Indeed, PG and CA showed complementary properties and thus enabled a regulation or a restoration effect on main aging-associated disorders. Thus, they can not only act on tissue architecture, cell–cell interactions and extracellular matrix protection but also on inflammation, cell longevity, skin immune system protection, skin radiance and stem cell survey. Finally, a clinical trial performed on Caucasian women confirmed AI anti-wrinkle efficacy, which was superior to that of a market reference ingredient. In the future, complementary experiments enabling a better understanding of the aging-induced decline of epidermal stem cells would be of a great interest.     

Pulsed measurement of high-reflectivity mirror phase retardances

The linear phase retardances of high-reflectivity mirrors are measured by use of the progressive modification of the polarization of a light pulse propagating in a passive Fabry-Perot cavity. This method permits determination of the linear phase retardance of a mirror with a precision of better than 0.05° and a sensitivity of better than 0.1° for any angle of incidence and any wavelength in the high-reflectivity domain of the mirror. This method also leads to a precise determination of the null-phase-retardance wavelength of the mirror.