Monte Carlo simulations combined with UHV-atmospheric pressure reaction studies on CO hydrogenation on cobalt

We show that useful information on catalytic reactions can be obtained using Monte Carlo simulations combined with experimental data from model catalysts. The experimental rate dependencies of CO hydrogenation on the partial pressures were used to guide the selection of different parameter values used in the simulations. The results give the following picture of the reaction conditions on the surface: hydrogen and carbon monoxide occupy different adsorption sites, the diffusion of hydrogen and the growth of hydrocarbon chains are fast processes, and the rate-limiting elementary reaction step is the termination of the hydrocarbon chains (-hydrogenation). The formation of longer chain hydrocarbons falls onto the line defined by the Anderson-Flory-Schulz distribution but the value of the chain growth parameter , obtained in the simulations, is higher than the experimental value.     

Unobtrusive stress detection on the basis of smartphone usage data

Stress has become an important health problem, but existing stress detectors are inconvenient in long-term real-life use because users either have to wear dedicated devices or expend notable interaction efforts in system adaptation to specifics of each person. Adaptation is necessary because individuals significantly differ in their perception of stress and stress responses, but typical adaptation employs supervised learning methods and hence requires fairly large sets of labelled data (i.e. information on whether each reporting period was stressful or not) from every user. To address these problems, we propose a novel unsupervised stress detector, based on using a smartphone as the only device and using discrete hidden Markov models (HMM) with maximum posterior marginal (MPM) decisions for analysis of phone data. Our detector requires neither additional hardware nor data labelling and hence is truly unobtrusive and suitable for lifelong use. Its accuracy was evaluated using two real-life datasets: in the first case, adaptation was based on very short (a few days) phone interaction histories of each individual, and in the second case—on longer histories. In these tests, the proposed HMM-MPM achieved 59 and 70% accuracies, respectively, which is comparable with results of fully supervised methods, reported by other works.     

Degradative and mechanical properties of a novel resorbable plating system during a 3-year follow-up in vivo and in vitro

We tested the tissue reactions and mechanical strength of a novel biodegradable craniomaxillofacial plating system, Inion CPS™, in the course of degradation. Plates and screws composed of l-lactide, d-lactide and trimethylene carbonate were implanted to the mandible and dorsal subcutis of 12 sheep. The animals were sacrificed at 6–156 weeks. Histological evaluation was done using paraffin and methylmetacrylate techniques. Degradative and mechanical properties during the follow-up were measured both of in vivo and in vitro implants. In light microscopy, the in vivo implant material began to fragment at 52 weeks and could not be detected at 104 weeks. No significant foreign body reactions were seen in the mandibles. The dorsal subcutis disclosed mild reactions, which were, however, not of clinical significance. The implants in vitro maintained their entire mass for 26 weeks and lost 63–80% of the mass by week 104. The inherent viscosity of the implants in vitro and in vivo diminished uniformly. The screws retained their shear strength for 12–16 weeks. The plates maintained their tensile strength for at least 6 weeks. The maximum capacity of the plates in 3-point bending tests diminished gradually by 87% in 26 weeks. In conclusion, the plates and screws examined maintain adequate strength for the healing period of a bone fracture or osteotomy, producing no harmful foreign body reactions. Dr Nieminen is a consultant for Inion Ltd., while the other co-authors do not have any conflicts of interest. Inion Ltd. has financed the costs related to the study sheep, including their housing.     

Epileptic seizure detection: a nonlinear viewpoint

This study concerns the detection of epileptic seizures from electroencephalogram (EEG) data using computational methods. Using short sliding time windows, a set of features is computed from the data. The feature set includes time domain, frequency domain and nonlinear features. Discriminant analysis is used to determine the best seizure-detecting features among them. The findings suggest that the best results can be achieved by using a combination of features from the linear and nonlinear realms alike.     

Properties of condensed spin-aligned atomic hydrogen from variational calculations

The optimal Jastrow-type ground-state wave function of spin-aligned atomic hydrogen is calculated using the pair potential of Kolos and Wolniewicz. The optimization is performed by solving the Euler equation in the hypernetted chain approximation. Accurate energies as well as pair-distribution functions are obtained. The Bose-Einstein condensate fraction is evaluated from the one-particle momentum distribution. The pair distribution function is also used to obtain stability criteria for the system and minimal values for the aligning magnetic field are calculated at low densities. The resulting values of the minimal aligning fields are considerably higher than those obtained previously.     

COATING THICKNESS EFFECTS ON THE LIFE OF TITANIUM NITRIDE PVD COATED TOOLS

The influence of coating thickness on the life time of titanium nitride (TiN) PVD coated high speed steel (HSS) cutting tools has been studied using planing and turning as machining test methods. The thickness of the coating was found to have a significant effect on tool life. In the planing tests a coating thickness of 2-3 μm was found to give the longest tool life. In the turning tests the tool life increased as the coating thickness increased, up to the maximum 6.0 μm thickness tested.

The chemical composition of the cutting fluid was also found to affect the tool life. The life of the coated tools was shorter in planing tests when using cutting fluids which contained EP (extreme pressure) -additives, sulfur additives showing shorter life than chloride.additives.     

Transient Receptor Potential Ankyrin 1 (TRPA1) Is Involved in Upregulating Interleukin-6 Expression in Osteoarthritic Chondrocyte Models

Transient receptor potential ankyrin 1 (TRPA1) is a membrane-bound ion channel found in neurons, where it mediates nociception and neurogenic inflammation. Recently, we have discovered that TRPA1 is also expressed in human osteoarthritic (OA) chondrocytes and downregulated by the anti-inflammatory drugs aurothiomalate and dexamethasone. We have also shown TRPA1 to mediate inflammation, pain, and cartilage degeneration in experimental osteoarthritis. In this study, we investigated the role of TRPA1 in joint inflammation, focusing on the pro-inflammatory cytokine interleukin-6 (IL-6). We utilized cartilage/chondrocytes from wild-type (WT) and TRPA1 knockout (KO) mice, along with primary chondrocytes from OA patients. The results show that TRPA1 regulates the synthesis of the OA-driving inflammatory cytokine IL-6 in chondrocytes. IL-6 was highly expressed in WT chondrocytes, and its expression, along with the expression of IL-6 family cytokines leukemia inhibitory factor (LIF) and IL-11, were significantly downregulated by TRPA1 deficiency. Furthermore, treatment with the TRPA1 antagonist significantly downregulated the expression of IL-6 in chondrocytes from WT mice and OA patients. The results suggest that TRPA1 is involved in the upregulation of IL-6 production in chondrocytes. These findings together with previous results on the expression and functions of TRPA1 in cellular and animal models point to the role of TRPA1 as a potential mediator and novel drug target in osteoarthritis.     

Evaluation of Water Resistance of Polyurethane Dispersion Coatings by Nuclear Magnetic Resonance Imaging

Proton nuclear magnetic resonance imaging (NMRI) at 300 MHz is used to evaluate water resistance of polyurethane dispersion coatings. A set of wood rods coated with an uncrosslinked aliphatic polyurethane dispersion, a plasticized poly(vinyl acetate) (PVAc) emulsion and a 5-minute-cure epoxy adhesive, respectively, are immersed in water at 25°C. The water penetration is followed by acquiring cross sectional images from the samples. The same procedure is used at 60°C to compare the performance of multifunctional polyaziridine and polycarbodiimide crosslinkers with the polyurethane dispersion. The signal intensities in the middle of the wood as a function of time show three characteristics for the systems: induction time, absorption rate, and saturation time. The water resistance of the uncrosslinked polyurethane dispersion coating is relatively good. The addition of 2% of the polycarbodiimide crosslinker does not improve the water resistance. However, the same amount of the polyaziridine crosslinker in 300 ± 50 μm thick coatings decreases the water absorption rate by a factor of ca. 14. The pot life for the 2% polyaziridine mixture is approximately three days and the coatings made from five-day-old mixture have three times faster water absorption rate relative to the fresh mixtures. The reliability of conventional water resistance tests is also discussed.