Catalytic Conversion of Hexanol to 2-Butyl-octanol Through the Guerbet Reaction

Activity of heterogeneous catalysts for synthesis of Guerbet alcohols from hexanol was evaluated. Commercial synthetic hydrotalcite (HT) was used in the aldol condensation reaction, which is a part of the Guerbet reaction network. HTs were calcined at different temperatures in order to modify their basicity and additionally, NaOH was applied in some experiments as a homogeneous base. The homogeneous base proved to be more efficient in aldol condensation experiments, while HT also performed in an acceptable way. Bi-functional metal containing HTs were synthesized by wet impregnation and co-precipitation methods employing different active metals. The materials were characterized with a number of methods, including CO₂-TPD, pyridine-FTIR, nitrogen physisorption, transmission electron microscopy, SEM–EDX and XRD. Copper containing catalysts produced hexyl-hexanoate with a very high selectivity, while Ni-containing counterparts exhibited the highest selectivity towards the Guerbet alcohol. The co-precipitated catalysts were more active in the current study than the ones produced by wet-impregnation. Nevertheless, synthesis of Guerbet alcohols from hexanol with a one-pot method proved to be challenging, with the best yield of the Guerbet product in 24 h being 5%. This is proposed to be largely due to thermodynamic limitations, which was confirmed by calculations of thermodynamics.     

Beyond Regional Clusters: On the Importance of Geographical Proximity for R&D Collaborations in a Global Economy—the Case of the Flemish Biotech Sector

When internal knowledge bases are insufficient for developing innovations, companies tend to collaborate with external R&D partners. According to a long-standing literature on “clusters”, “industrial districts”, “local production systems” and “regional innovation systems”, geographical proximity between innovation partners is considered a precondition for inter-organizational collaborations: proximity is said to facilitate trust, the transfer of tacit knowledge and the intensity of interactions. This article investigates the importance of geographical proximity for R&D collaborations between biotech firms and their innovation partners. Are geographically close innovation partners likely to collaborate more intensely? Studies of the Flemish biotech industry shed light on this question. Regression analyses combined with qualitative interview data reveal that geographical proximity has become less important for inter-organizational collaborations. Owing to lower communication and transportation costs, innovation partners can easily collaborate even when they are not situated close to each other. This leads us to conclude that globalization transforms inter-organizational collaborations.     

Effects of non-optimal focusing on dual-frequency ultrasound measurements of bone

In pulse-echo (PE) ultrasound measurements, the use of focused transducers is desirable for quantitative assessment of bone characteristics because of the attenuation in the overlying soft tissues. However, the variable thickness and composition of the soft tissue overlying bone affect the focal depth of the ultrasound beam and induce errors into the measurements. To compensate for the attenuation-related effects caused by the interfering soft tissue (i.e., fat and lean tissue), a dual-frequency ultrasound (DFUS) technique was recently introduced. The aim of this study was to investigate the effect of non-optimal focal depth of the ultrasound beam on the determination of the integrated reflection coefficient (IRC) of bone when overlaid by an interfering layer composed of oil and water. The feasibility of the DFUS-based correction of the IRC was evaluated through numerical simulations and experimental measurements. Even when the interfering layer-bone interface was out of focus, the total thickness of the interfering layer could be accurately determined with the technique. However, based on the simulations, the errors in the determination of the composition of the interfering layer increased (0.004 to 113.8%) with the increase in distance between the interfering layer-bone interface and the focus of the ultrasound beam. Attenuation compensation, based on the true composition of the interfering layer, resulted in an average relative error of 22.3% in the IRC values calculated from the simulations. Interestingly, the attenuation compensation with the interfering layer composition estimated using the DFUS technique resulted in a smaller average relative error of 14.9% in the IRC values. The simulations suggest that DFUS can reduce the errors induced by soft tissue in bone PE ultrasound measurements. The experimental measurements indicate that the accuracy of the IRC measurements is rather similar when using DFUS correction or correction based on the true composition of the interfering layer. However, the results suggest that accurate determination of soft tissue composition may be difficult without optimal focusing of the ultrasound beam on the soft tissue-bone interface.     

Sustainability indicators for anticipating the fickleness of human–environmental interaction

The development of environmental indicators is dominated by the so-called pressure–state–response (PSR) model. The PSR contains a set of indicators measuring anthropogenic pressure (P) on the environment, the state (S) of the environment resulting from such pressure, and the societal response (R) to ease the pressure. The strength of the PSR is its acknowledgement of the causal relationship between the state of the environment and human activity. Its major weakness, however, is the lack of sophistication of the mathematical and cognitive models representing the causal relationship. As a result, current indicator systems based on the PSR fail to take into account contingencies in human–environmental interaction that make the future state of the system difficult to ascertain. Recognizing the fickleness of human beings and nature will result in very different indicators from those traditionally developed. In particular, the article identifies the following important areas of indicator development: (1) indicators of ecosystem impacts of production, which measure changes in production outputs and environmentally significant inputs; (2) indicators of bounded carrying capacity, which utilize alternative scenarios of human–environmental interaction to specify the ecosystem-specific limits that societies might impose on industrial production; (3) indicators of congruence between ecosystems, institutions and production, which measure the agreement between the functions of an ecosystem and the institutional rules governing its management; and (4) indicators of technological and institutional path dependence, which observe and potentially strengthen lock-ins in human–environmental interaction. These development challenges imply that sustainability indicators should be considered more as vehicles for improving communication between different communities of experts on the sustainability of a particular system of human–environmental interaction, and less as universal measures of sustainability.     

Tailoring surface properties of paper using nanosized precipitated calcium carbonate particles

Pigment particles used in paper coatings are typically of micrometer size and consequently the thickness of the coatings is, even at its lowest, in micrometer scale. Progress in nanotechnology has given way to the development of nanosized materials to be used in coatings, yet their exploitation has not been studied to a great extent. This study examines utilization of nanosized precipitated calcium carbonate (nanoPCC) particles in nanoscale thin coating layers. In contrast to commonly used coatings, a thin nanoparticle-based coating was targeted to change the substrate surface characteristics via controlled surface structure rather than via high coat weight. A novel approach for stabilizing and modifying the nanoPCC particles with pectin and alkenyl succinic anhydride (ASA) was utilized and a nanoparticle coating with uniform particle distribution was created. The coating applied on paper substrate was hydrophobic, having a water contact angle of 125°. Particle surface modification provided dispersion stability, enabling control of the coating layer structure. The introduced concept provides a new approach to paper coatings utilizing controlled deposition of nanoparticles with extremely low coat weight, yet having high impact on substrate surface properties. Additionally, as paper is an environmentally sound product, the approach to form a controllable nanostructure on a green substrate has potential in applications outside the traditional paper products.     

Nanoliter Scale Parallel Liquid–Liquid Extraction for High-Throughput Purification on a Droplet Microarray

In the current drug discovery process, the synthesis of compound libraries is separated from biological screenings both conceptually and technologically. One of the reasons is that parallel on-chip high-throughput purification of synthesized compounds is still a major challenge. Here, on-chip miniaturized high-throughput liquid–liquid extraction in volumes down to 150 nL with efficiency comparable to or better than large-scale extraction utilizing separation funnels is demonstrated. The method is based on automated and programmable merging of arrays of aqueous nanoliter droplets with organic droplets. Multi-step extraction performed simultaneously or with changing conditions as well as handling of femtomoles of compounds are demonstrated. In addition, the extraction efficiency is analyzed with a fast optical readout as well as matrix-assisted laser desorption ionization-mass spectrometry on-chip detection. The new massively parallel and miniaturized purification method adds another important tool to the chemBIOS concept combining chemical combinatorial synthesis with biological screenings on the same miniaturized droplet microarray platform, which will be essential to accelerate drug discovery.     

Development of separation technology for the removal of radium-223 from targeted thorium conjugate formulations. Part II: purification of targeted thorium conjugates on cation exchange columns

Tumor targeting pharmaceuticals will play a crucial role in future pharma pipelines. The targeted thorium conjugate (TTC) therapeutic platform could provide real benefit to patients, whereby targeting moieties like monoclonal antibodies are radiolabelled with the alpha-emitting radionuclide thorium-227 (²²⁷Th, t_1/2?=?18.7?days). A potential problem could be the accumulation of the long-lived daughter nuclide radium-223 (²²³Ra, t_1/2?=?11.4?days) in the drug product during manufacturing and distribution. Therefore, the level of ²²³Ra must be standardized before administration to the patient. The focus in this study has been the removal of ²²³Ra, as the other progenies will have a very limited stay in the formulation. In this study, the purification of TTCs labeled with decayed ²²⁷Th has been explored. Columns packed with a strong cation exchange resin have been used to sequester ²²³Ra. The separation of TTC from ²²³Ra has been evaluated as influenced by both formulation and process parameters with a design of experiments (DOE) study; including citrate or acetate buffer, pH, buffer concentration, presence or absence of pABA?+?EDTA, resin amount and sodium chloride concentration. The aim was to achieve a separation with high sorption of ²²³Ra and accompanying low TTC sorption. The results were analyzed by multivariate analysis. Four regression models of TTC and ²²³Ra sorption from citrate and acetate buffered formulations were developed. The predictive accuracy of sorption in the four statistical models was given by standard deviations and confidence intervals. The TTC sorption in citrate and acetate buffered formulations was affected by the identical variables and the variation in TTC sorption was comparable for the two models. However, the DOE variables had a significantly stronger impact on the ²²³Ra sorption in citrate buffered formulations than the ²²³Ra sorption in acetate buffer. An optimal separation with a TTC sorption below 25% and ²²³Ra sorption above 90% can be achieved in both citrate and acetate buffered formulations. Stability studies of radiochemical purity (RCP) indicated that the measured ²²⁷Th values may be partly due to free ²²⁷Th and not TTC, but the results indicate that TTC stability may be controlled by optimizing formulation parameters. Hence, the sorption data and the regression models presented must be reviewed and further explored with regard to what is known about the stability of the TTC in the different buffered formulations.     

Local field asymmetry drives second-harmonic generation in non-centrosymmetric nanodimers

We demonstrate that second-harmonic generation (SHG) from arrays of non-centrosymmetric T-shaped gold nanodimers with a nanogap arises from asymmetry in the local fundamental field distribution and is not related strictly to nanogap size. Calculations show that the local field contains orthogonal polarization components not present in the exciting field, which yield the dominant SHG response. The strongest SHG responses occur through the local surface susceptibility of the particles for a fundamental field distributed asymmetrically at the particle perimeters. Weak responses result from more symmetric distributions despite high field enhancement in the nanogap. Nearly constant field enhancement persists for relatively large nanogap sizes.     

Motion adaptive scan rate up-conversion

The interlaced scan format and the low frame rate in current television systems cause visible degradation in picture quality. To improve the picture, scan rate up-conversion can be implemented in the receiver. Typically, the up-conversion algorithms needed in stationary scenes are different from those needed in nonstationary scenes. In this paper we discuss problems related to scan rate up conversion and motion detection. We present an algorithm that adapts to the motion in the picture and yet effectively eliminates most of the artifacts caused by imperfect motion detection. The algorithm is based on a weighted median filter structure and a simple motion detector. The weights of the median filter are adapted according to the motion detector output. All algorithms discussed have been tested with real sequences using a video sequencer.Invited Paper     

Microstructure, creep properties, and failure mechanism of SnAgCu solder joints

The effect of microstructure on the creep properties and the failure mechanism of SnAgCu solder joints was studied. Single overlap shear specimens made of FR-4 printed circuit boards (PCBs) with organic solderability preservative (OSP), NiAu, and immersion Sn surface finish were reflow-soldered with hypoeutectic, eutectic, and hypereutectic SnAgCu solder paste. Creep tests of the solder joints were performed at 85°C and 105°C under constant load. The effect of microstructure on the creep behavior of the joints was studied by examining the fracture surfaces and cross-sectional samples of the tested joints. Results show that the intermetallic compound at the interface between the PCB and solder affects the fracture behavior of SnAgCu solder joints, thus creating a significant difference in the creep properties of solder joints on different surface finishes. Composition of SnAgCu solder was also found to affect the creep properties of the joints.