Mo6S9-xIx nanowire recognitive molecular-scale connectivity

We report on a new highly reproducible route to recognitive self-assembly of molecular-scale circuits using sulfur-terminated subnanometer diameter Mo6S9-xIx (MoSIx) molecular nanowires. We demonstrate solution-processed attachment of MoSIx connecting leads to gold nanoparticles (GNPs). We also show that naked nanowires have the potential to bind thiolated proteins such as green fluorescent protein directly, thus providing a universal construct to which almost any protein could be attached. We further demonstrate three-terminal branched circuits with GNPs, opening a self-assembly route to multiscale complex molecular-scale architectures at the single-molecule level.     

The effect of polymer molecular weight and crosslinking reactions on the adhesion properties of microsphere water-based acrylic pressure-sensitive adhesives

In this work, the effect of polymer molecular weight and crosslinking reactions on the end-use properties of the microsphere water-based acrylic pressure-sensitive adhesives (PSA) is presented. Polymer molecular weight and polymer microstructure were regulated using different chain transfer agent (CTA) concentrations and by addition of a diacrylic monomer (MM). The adhesion properties of the synthesized PSAs were characterized via measurements of tack, peel adhesion and shear strength. The results of experiments have shown that the kinetics of suspension polymerization is relatively independent on the amount of CTA and MM. The amount of gel phase in the adhesive was reduced with increasing amount of CTA agent, and gel phase amount may be considered as a function of polymer molecular weight. With a combination of CTA and MM was possible to regulate the amount of formed gel phase in the adhesive, as well sol phase molecular weight. All of the measured adhesion properties strongly depend on molecular weight of the synthesized polymer and on the amount of gel phase. For adhesives synthesized solely with addition of CTA, tack decreased with lower polymer molecular weight and consecutively also with lower amount of gel phase. The same trend was also observed for peel strength measurements, whereas a cohesive failure was observed for adhesives with low amount of gel phase. A maximum value for tack and shear strength was observed at 80 wt% of gel phase. In case of syntheses with a combination of CTA and MM (amount of gel phase in range from 70 to 80 wt%), tack values were distributed in quite narrow range. On the other hand, peel strength values decreased in comparison with adhesives synthesized only with CTA, regardless to the equal amount of gel phase. Poor shear strength was observed for all adhesives synthesized by combination of CTA and MM.     

Approaches to Inactivating Aflatoxins—A Review and Challenges

According to the World Health Organization, the contamination of crops with aflatoxins poses a significant economic burden, estimated to affect 25% of global food crops. In the event that the contaminated food is processed, aflatoxins enter the general food supply and can cause serious diseases. Aflatoxins are distributed unevenly in food or feedstock, making eradicating them both a scientific and a technological challenge. Cooking, freezing, or pressurizing have little effect on aflatoxins. While chemical methods degrade toxins on the surface of contaminated food, the destruction inside entails a slow process. Physical techniques, such as irradiation with ultraviolet photons, pulses of extensive white radiation, and gaseous plasma, are promising; yet, the exact mechanisms concerning how these techniques degrade aflatoxins require further study. Correlations between the efficiency of such degradation and the processing parameters used by various authors are presented in this review. The lack of appropriate guidance while interpreting the observed results is a huge scientific challenge.     

The effectiveness of the SEA process in Slovenia

This article focuses on the analysis of strategic environmental assessment (SEA) effectiveness in Slovenia. Apart from some general information on the SEA legal framework and guidance, the article mainly explores the political context, substantive, transactive, normative, knowledge/learning and pluralist effectiveness of SEA in Slovenia. An online questionnaire was prepared to collect information and views related to the stated aspects of SEA effectiveness from key stakeholders involved in the process. The survey results indicate that SEA in Slovenia is only partially effective. The most commonly recognised problems related to the substantive effectiveness of SEA are linked to weak control over the implementation of the mitigation measures and their effectiveness. With regard to transactive effectiveness, the SEA extends the planning process and is mostly assessed to have a low cost–benefit ratio. Personnel and organisations involved in SEA processes have very diverse skills and efficiency. In relation to normative effectiveness, neglect of social and economic components occurs. SEA does not seem to be very successful in changing the way of thinking, which has a negative impact on knowledge effectiveness. Pluralist effectiveness could be also improved, especially with regard to better integration of views from the public into the planning process.     

PolyHIPEs from Methyl methacrylate: Hierarchically structured microcellular polymers with exceptional mechanical properties

Highly porous monoliths with excellent mechanical properties and porosity of up to 90% were prepared by the polymerisation of high internal phase emulsions (HIPE) containing methyl methacrylate (MMA) and ethylene glycol dimethacrylate (EGDMA). Materials with open cellular morphology and cavity diameters between 0.6 and 4.5 μm are obtained using a homogenizer and between 0.8 and 25 μm using a standard overhead stirrer. Samples with 80% pore volume have E-moduli up to 180 MPa, while 75% porous samples exhibit E-moduli up to 211 MPa. A dependence of mechanical properties on cavity size distribution is identified, where a more hierarchically developed porous structure results in significantly better mechanical properties.     

Investigation of rubber–rubber blends miscibility

Polybutadiene rubber, poly(styrene‐co‐butadiene) rubber, natural rubber, and their blends were investigated to estimate the degree of miscibility of components in the blends. The morphology of a rubber–rubber blend controls its rheological properties and glass transition behavior. Therefore, two different measuring techniques were used: rheological characterization of blends by the rubber process analyzer (RPA) and temperature modulated differential scanning calorimetry (TMDSC). To study the dependence of complex viscosity on blend composition, two commonly used empirical mixing rules were applied: the log‐additivity mixing rule and the quadratic mixing rule. Viscoelastic properties of the examined samples were described by mechanical and relaxation spectra. Since the RPA measurements cannot be performed in a wide frequency range, the experimental results cannot offer a complete overview. Also, the quantitative analysis using the differential of the heat capacity, dC_p/dT, versus the temperature signal from TMDSC did not allow to calculate the weight fraction of the interface for all types of the blends under investigation. However, the combination of the two techniques applied provided complementary information on blend morphology and rubber–rubber miscibility. POLYM. ENG. SCI. 46:1649–1659, 2006. © 2006 Society of Plastics Engineers.     

The Enhanced Cytotoxic Effects in B-Cell Leukemia and Lymphoma Following Activation of Prostaglandin EP4 Receptor and Targeting of CD20 Antigen by Monoclonal Antibodies

Anti-CD20 monoclonal antibodies (MAbs) have revolutionized the treatment of B-cell leukemia and lymphoma. However, many patients do not respond to such treatment due to either deficiency of the complementary immune response or resistance to apoptosis. Other currently available treatments are often inadequate or induce major side effects. Therefore, there is a constant need for improved therapies. The prostaglandin E2 receptor 4 (EP4) receptor has been identified as a promising therapeutic target for hematologic B-cell malignancies. Herein, we report that EP4 receptor agonists PgE1-OH and L-902688 have exhibited enhanced cytotoxicity when applied together with anti-CD20 MAbs rituximab, ofatumumab and obinutuzumab in vitro in Burkitt lymphoma cells Ramos, as well as in p53-deficient chronic lymphocytic leukemia (CLL) cells MEC-1. Moreover, the enhanced cytotoxic effects of EP4 receptor agonists and MAbs targeting CD20 have been identified ex vivo on primary lymphocytes B obtained from patients diagnosed with CLL. Incubation of cells with PgE1-OH and L-902688 preserved the expression of CD20 molecules, further confirming the anti-leukemic potential of EP4 receptor agonists in combination with anti-CD20 MAbs. Additionally, we demonstrated that the EP4 receptor agonist PgE-1-OH induced apoptosis and inhibited proliferation via the EP4 receptor triggering in CLL. This work has revealed very important findings leading towards the elucidation of the anticancer potential of PgE1-OH and L-902688, either alone or in combination with MAbs. This may contribute to the development of potential therapeutic alternatives for patients with B-cell malignancies.     

Solventless UV crosslinkable acrylic pressure sensitive adhesives

The synthesis and characterization of solventless acrylic UV crosslinkable pressure sensitive adhesives are presented. Different prepolymers were synthesized using bulk polymerization procedure. The reaction mixture consisted of acrylic monomers (2-ethylhexyl acrylate, acrylic acid and t-butyl acrylate), azobisisobutyronitrile initiator, chain transfer agent n-dodecylmercaptan and unsaturated UV photoinitiator 4-acryloyloxybezophenone, which was copolymerized into polymer backbone. Different formulations were tested and the prepolymer was characterized by viscosity measurements and final monomer conversions. The prepolymers were coated onto PET foil and crosslinked by application of UV light source. Peel adhesion at 180° on glass plate was measured. Gel phase was determined using the Soxhlet extraction and copolymer glass transition temperatures (T_g) were analyzed by differential scanning calorimetry (DSC). Results showed that the final monomer conversions in highly exothermic bulk polymerization reached a level between 75% and 90%. Prepolymer viscosity was highly influenced by change in polymer molecular weight and by addition of acrylic acid as a comonomer. On the other hand, the viscosity remained at the low level when t-butyl acrylate was used. The amount of gel phase for all adhesives was above 60 wt.%. Peel strength measurements showed decrease in peel strength with decreasing polymer molecular weight and increase of peel, when acrylic acid was used as a comonomer. All adhesive coatings with t-butyl acrylate comonomer showed cohesive failure.     

Translucent Yttria‐ and Silica‐Doped Mullite Ceramics with Anisotropic Grains Produced by Spark Plasma Sintering

Translucent, high‐performance, mullite ceramics with anisotropic grains were prepared by the spark plasma sintering (SPS) of a powder mixture consisting of commercial mullite powder, which already contained small amounts of alumina (θ and α) and silica (cristobalite) (≤3 wt% in total), to which 2 and 1 wt% of yttria and amorphous silica was admixed, respectively. The combination of low‐viscosity Y₂O₃–Al₂O₃–SiO₂ transient liquid formation and SPS sintering provided enhanced densification, also provoking anisotropic grain growth (which became exaggerated after 20 min of SPS dwell time), at a relatively low sintering temperature of 1370°C. In this way, it was possible to meet the conflicting demands for obtaining a dense mullite ceramic with anisotropic grains, ensuring good mechanical properties, while preserving a noticeable light transmittance. In terms of mechanical and optical properties, the best results were obtained when SPS dwell times of 5 and 10 min were employed. The as‐sintered samples possessed densities in the range 3.16–3.18 g/cm³, anisotropic grains with an aspect ratio (AR) of 7 and a grain thickness of approximately 0.45 μm, a flexural strength between 350 and 420 MPa, a Vickers indentation toughness and a hardness of approximately 2.45 MPa·m^1/2 and 15 GPa, respectively, and an optical transmittance of between 30% and almost 50% in the IR range.