Characterisation of alumina-supported vanadium oxide catalysts by kinetic analysis of H2-TPR data

Alumina-supported vanadium oxide catalysts with vanadium contents of 2, 5 and 11 wt.% were prepared by incipient wetness impregnation and characterised by XRD, Raman spectroscopy and H₂-TPR. The catalysts with the low vanadium contents contained vanadium mainly in the well-dispersed phase, but the catalyst with the highest vanadium content contained also some crystalline AlVO₄ according to XRD and Raman spectroscopic results. The reduction kinetics of the vanadium catalysts was modelled based on the hydrogen consumption during the TPR. The reduction kinetics could be described with a single-reducible-site random nucleation model for the catalyst containing the lowest amount of vanadium. The reduction kinetic models for the other catalysts required a combination of multiple processes to describe the experiments properly. In the catalyst with 5 wt.% V, a part of vanadium species possibly reduces as a homogeneous random nucleation process, but topochemical reduction by nuclei growth also takes place. In the catalyst with 11 wt.% V, reduction by nuclei growth seems to be the predominant reduction mechanism. The characterisation of the reduced catalysts by XRD and during reduction by Raman spectroscopy enabled the identification of the features of the TPR profiles.     

Characterization of the sec1-1 and sec1-11 mutations.

Sec1 proteins are implicated in positive and negative regulation of SNARE complex formation. To better understand the function of Sec1 proteins we have identified the nature of the temperature-sensitive mutations in sec1-1 and sec1-11. The sec1-1 mutation changes a conserved glycine(443) to glutamic acid. The sec1-11 mutation changes a highly conserved arginine(432) to proline. Based on homology and the crystal structure of the mammalian nSec1p, the corresponding amino acids localize to the 3b domain of nSec1p. Compared to the wild-type Sec1p the mutant proteins are less abundant even at the permissive temperature. Thus, the R432P and G443E mutations may cause structural alterations that affect folding and make the mutant proteins more susceptible to degradation. The remaining part is sufficient for growth and protein secretion at 24 degrees C and thus is likely to be properly folded. At 37 degrees C the mutant proteins become non-functional. In pulse-chase-type experiments the newly synthesized Sec1-1 and Sec1-11 proteins decayed similarly with the wild-type protein. Thus, the non-functionality of the mutant proteins cannot be explained by denaturation-induced degradation only. It is possible that the newly synthesized mutant proteins fold slowly and are susceptible to degradation before they have managed to fold and associate with other proteins. The mutant proteins were unable to interact with the Sec1p-interacting proteins Mso1p and Sso2p in the two-hybrid assay, even at the permissive temperature. These results localize sec1-1 and sec1-11 mutations to a domain of Sec1p and suggest a mechanism by which sec1-1 and sec1-11 cells become temperature-sensitive.     

Holistic Analysis on the Concept of Process Metallurgy and Its Application on the Modeling of the AOD Process

The criteria for evaluating the applied fields of science often are based on practical justifications such as functionality and applicability instead of objectiveness or truthfulness, which typically are emphasized in the more theoretical fields of science. The use of practical justifications is understandable when considering the value of an applied field of science, but it should be noted that this kind of approach leaves out some aspects that should be covered while considering the nature and meaning of the fundamental concepts of a certain field. This article analyzes the concept of process metallurgy from different perspectives and proposes a model that helps show the characteristic features and connections of the different aspects of the process metallurgy. Conceptual analysis was used to evaluate research concerning the modeling of the argon oxygen decarburization process, and it was concluded that holistic analysis of the fundamental concepts has certain advantages also on a practical level; it helps to visualize the connections among research, education, and practical applications as well as the links among different areas of research or education. With the awareness of these connections, it is easier to plan, visualize, and evaluate the research and its goals, methods, results, extent, and need for competence and to perceive the relations among the different areas of research as well as among the different researchers and to evaluate the validity of the research.     

Regeneration and Recycling of Aqueous Periodate Solution in Dialdehyde Cellulose Production

Abstract

The regeneration of aqueous iodate solution from the regioselective periodate oxidation of softwood cellulose pulp to dialdehyde cellulose using hypochlorite as a secondary oxidant was studied. The influence of oxidation time on the pulp dissolution and regeneration efficacy was examined in particular. In addition, the recycling of regenerated periodate solution back to oxidation was clarified. The solutions from the 10 and 15 min oxidations were regenerated with 100% conversion efficacy when 1.2–1.4 times the stoichiometric amounts of hypochlorite were used. However, the regeneration efficacy decreased when the reaction time in the oxidation increased to 30 min because the content of soluble impurities, which consumed the hypochlorite in the side-reactions, increased significantly as the oxidation reaction proceeded. The regenerated solutions possessed good oxidation performance, showing that periodate was successfully regenerated using hypochlorite and supporting the assumption that periodate can be effectively recycled in the process when short oxidation times are used.     

Social adjustment of children with and without learning disabilities in integrated classrooms.

The social adjustment of 46 children with learning disabilities (LDs) and 199 children without LDs who were integrated full-time in 3rd-grade classrooms was examined. No differences were found in the proportions of children with LDs and without LDs across accepted and unpopular sociometric groups. Two thirds of children with LDs had at least 1 reciprocal friend, and more than half had a friendship with a classmate without LDs. Girls with LDs received the highest number of negative nominations and were the least preferred. Group comparisons of socially adjusted and nonadjusted children, with and without LDs, showed that teachers perceived the socially adjusted children with LDs to be less socially and academically competent than adjusted children with LDs. Results are discussed in terms of the effects of educational setting and classroom composition on children's social adjustment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Outcome and attributional disagreements between students and their teachers.

Teachers' and students' outcome interpretations, attributions for the outcome, expectancies of future exam outcome, and perceptions concerning instrumental actions were compared after a math exam. One third of the students disagreed with their teacher about whether the exam outcome was a success or a failure; teachers evaluated the outcomes more positively than did students. When the students and the teachers agreed on the outcome interpretation, their mean attributional ratings did not apparently differ. However, ratings of teacher–student dyads revealed considerable attributional differences. After perceived failure, the dyadic attributional disagreements were related to disagreements concerning the instrumental actions needed for future success. Also, given failure, the more discrepant the dyad members' views of the stability of the attributions were, the more discrepant were their future expectations. Disagreements between students and teachers concerning outcome evaluation, causal perception, and future expectancy are discussed in terms of students' and teachers' biases. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hierarchical Assembly of Nanocellulose‐Based Filaments by Interfacial Complexation

In the present study, interfacial complexation spinning of oppositely charged cellulose‐materials is applied to fabricate hierarchical and continuous nanocellulose based filaments under aqueous conditions by using cationic cellulose nanocrystals with different anionic celluloses including soluble sodium carboxymethyl cellulose and insoluble 2,2,6,6‐tetramethylpiperidinyl‐1‐oxy radical‐oxidized cellulose nanofibers and dicarboxylated cellulose nanocrystals (DC‐CNC). The morphologies of the wet and dry nanocellulose based filaments are further investigated by optical and electron microscopy. All fabricated continuous nanocellulose based filaments display a hierarchical structure similar to the natural cellulose fibers in plant cells. As far as it is known, this is not only the first report about the fabrication of nanocellulose based filaments by interfacial complexation of cationic CNCs with anionic celluloses but also the first demonstration of fabricating continuous fibers directly from oppositely charged nanoparticles by interfacial nanoparticle complexation (INC). This INC approach may provide a new route to design continuous filaments from many other oppositely charged nanoparticles with tailored characteristics.     

Matrix Metalloproteinase 8 Expression in a Tumour Predicts a Favourable Prognosis in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a significant cause of cancer-related death globally, and, despite improvements in diagnostics and treatment, survival remains poor. Matrix metalloproteinases (MMPs) are enzymes involved in stroma remodelling in inflammation and cancer. MMP-8 plays a varied prognostic role in cancers of the gastrointestinal tract. We examined the prognostic value of MMP-8 immunoexpression in tumour tissue and the amount of MMP-8-positive polymorphonuclear cells (PMNs) in PDAC and their association with immune responses using C-reactive protein (CRP) as a marker of systemic inflammation. Tumour samples from 141 PDAC patients undergoing surgery in 2002–2011 at the Department of Surgery, Helsinki University Hospital were stained immunohistochemically, for which we evaluated MMP-8 expression in cancer cells and the amount of MMP-8-positive PMNs. We assessed survival using the Kaplan–Meier analysis while uni- and multivariable analyses relied on the Cox proportional hazards model. A negative MMP-8 stain and elevated CRP level predicted a poor prognosis (hazard ratio [HR] = 6.95; 95% confidence interval (CI) 2.69–17.93; p < 0.001) compared to a positive stain and low CRP level (<10 mg/L). The absence of PMNs together with an elevated CRP level also predicted an unfavourable outcome (HR = 3.17; 95% CI 1.60–6.30; p = 0.001). MMP-8 expression in the tumour served as an independent positive prognostic factor (HR = 0.33; 95% CI 0.16–0.68; p = 0.003). Tumour MMP-8 expression and a low CRP level may predict a favourable outcome in PDAC with similar results for MMP-8-positive PMNs and low CRP levels. Tumoural MMP-8 expression represents an independent positive prognostic factor in PDAC.     

Phenotypic and molecular assessment of antimicrobial resistance in Lactobacillus paracasei strains of food origin

Antimicrobial resistance data in food-associated lactic acid bacteria (LAB) such as lactobacilli are mostly based on nonstandardized methodologies and/or have been obtained for only a limited number of strains. This susceptibility study included a diverse collection of 115 isolates mainly of food origin originally identified as Lactobacillus paracasei or Lactobacillus casei. Upon reidentification and removal of potential replicate isolates using repetitive DNA element PCR fingerprinting, 65 genotypically unique L. paracasei strains and the L. casei type strain were selected for broth microdilution and Etest assays using the LAB susceptibility test medium. In both methodologies, strains appeared uniformly susceptible to ampicillin and clindamycin but exhibited natural resistance to streptomycin and gentamicin. Three L. paracasei strains from cheese displayed acquired resistance to tetracycline (MIC > or = 32 microg/ml) and/or to erythromycin (MIC >16 microg/ml), which was linked to the presence of a tet(M) or tet(W) gene and/or an erm(B) gene, respectively. Partial sequencing revealed that the tet(M) genes found in two of these strains belonged to two tet(M) sequence homology groups previously found in enterococci. Collectively, phenotypic and genotypic data allowed us to propose tentative epidemiological cutoffs for L. paracasei and L. casei for differentiating susceptible strains from those strains harboring one or more acquired resistance factors.     

Environmental contamination at Finnish shooting ranges--the scope of the problem and management options

In Finland, shooting ranges are among the most common activities causing soil contamination. According to our study based on questionnaires and previous regional surveys, the total number of Finnish outdoor shooting ranges is between 2000 and 2500. Most of the ranges are small and only ca. 5% exceed 20 ha. Almost a third of the ranges can cause a groundwater pollution risk, while only few cause an immediate health risk. In the first instance, 50-60 shooting ranges identified as being high-risk areas should be investigated in detail. At present, the risk management options at Finnish shooting ranges are very limited. Hence, soil excavation combined with disposal is the most common remediation technique. Some of the remediation methods used in other countries have been proven unsuitable in Finnish conditions. Therefore, new, feasible, cost-effective and economical remediation technologies are needed. To exclude future contamination, a total ban of lead shot would be the most effective way.