A numerical method for the evaluation of non-linear transient moisture flow in cellulosic materials

A numerical method for the transient moisture flow in porous cellulosic materials like paper and wood is presented. The derivation of the model is based on mass conservation for a mixture containing a vapour phase and an adsorbed water phase embedded in a porous solid material. The principle of virtual moisture concentrations in conjunction with a consistent linearization procedure is used to produce the iterative finite element equations. A monolithic solution strategy is chosen in order to solve the coupled non-symmetric equation system. A model for the development of higher order sorption hysteresis is also developed. The model is capable of describing cyclic hardening as well as cyclic softening of the equilibrium water concentration. The model is verified by comparison with the measured response to natural variations in temperature and humidity. A close agreement of the simulated results to measured data is found. Copyright (c) 2005 John Wiley & Sons, Ltd

Sense of Coherence in Persons with Dementia and Their Next of Kin : A Mixed-Method Study

Indications of dementia disease include deterioration of memory, thinking, behaviour, and the ability to perform everyday activities. Any of these symptoms can lead to stress and difficulties organizing everyday life. As a way to view factors that support human health and well-being despite stressful situations, Antonovsky introduced a salutogenic model. This model proposes that sense of coherence primarily determines physical and mental health i.e. psychological well-being. Having a sense of coherence in everyday life can reduce the impact of stress on the individual in everyday life. The study’s aim of this study was to explore how participants in existing support groups scored on the Sense of Coherence Scale (SOC), and what they perceived as contributory factors to a meaningful, manageable, and comprehensible everyday life in the presence of dementia using a mixed method. Persons with dementia had the highest scores on the SOC scale and their partners the lowest. Persons with dementia expressed that being with others who understood them made their everyday life comprehensible and manageable. Their partners expressed that learning about dementia was helpful in managing and comprehending everyday situations. The adult children expressed that it was meaningful to care for their parents and they scored slightly higher than the partners on the SOC scale. Long-term ongoing support supplemented with information and social support can contribute to the sense of coherence in persons with dementia and their next of kin

Exceptionally rich keratinolytic enzyme profile found in the rare actinomycetes Amycolatopsis keratiniphila D2(T)

The non-spore forming Gram-positive actinomycetes Amycolatopsis keratiniphila subsp. keratiniphila D2(T) (DSM 44,409) has a high potential for keratin valorization as demonstrated by a novel biotechnological microbial conversion process consisting of a bacterial growth phase and a keratinolytic phase, respectively. Compared to the most gifted keratinolytic Bacillus species, a very large number of 621 putative proteases are encoded by the genome of Amycolatopsis keratiniphila subsp. keratiniphila D2(T), as predicted by using Peptide Pattern Recognition (PPR) analysis. Proteome analysis by using LC-MS/MS on aliquots of the supernatant of A. keratiniphila subsp. keratiniphila D2(T) culture on slaughterhouse pig bristle meal, removed at 24, 48, 96 and 120 h of growth, identified 43 proteases. This was supplemented by proteome analysis of specific fractions after enrichment of the supernatant by anion exchange chromatography leading to identification of 50 proteases. Overall 57 different proteases were identified corresponding to 30% of the 186 proteins identified from the culture supernatant and distributed as 17 metalloproteases from 11 families, including an M36 protease, 38 serine proteases from 4 families, and 13 proteolytic enzymes from other families. Notably, M36 keratinolytic proteases are prominent in fungi, but seem not to have been discovered in bacteria previously. Two S01 family peptidases, named T- and C-like proteases, prominent in the culture supernatant, were purified and shown to possess a high azo-keratin/azo-casein hydrolytic activity ratio. The C-like protease revealed excellent thermostability, giving promise for successful applications in biorefinery processes. Notably, the bacterium seems not to secrete enzymes for cleavage of disulfides in the keratinous substrates

The role of subsite +2 of the Trichoderma reesei beta-mannanase TrMan5A in hydrolysis and transglycosylation

The N-terminal catalytic module of beta-mannanase TrMan5A from the filamentous fungus Trichoderma reesei is classified into family 5 of glycoside hydrolases. It is further classified in clan A with a (beta/alpha)(8) barrel configuration and has two catalytic glutamates (E169 and E276). It has at least five other residues conserved in family 5. Sequence alignment revealed that an arginine (R171 in TrMan5A) is semi-conserved among beta-mannanases in family 5. In a previously published mannobiose complex structure, this residue is positioned in hydrogen bonding distance from the C2 hydroxyl group of the mannose residue bound at the +2 subsite. To study the function of R171, mutants of this residue were constructed. The results show that arginine 171 is important for substrate binding and transglycosylation. A mutant of TrMan5A with the substitution R171K displayed retained activity on polymeric galactomannan but reduced activity on oligosaccharides due to an increase of K-m. While the wild-type enzyme produces mannobiose as dominant product from mannotetraose the R171K mutant shows an altered product profile, producing mannotriose and mannose. The cleavage pattern of mannotetraose was analysed with a method using isotope labelled water ((H2O)-O-18) and mass spectrometry which showed that the preferred productive binding mode of mannotetraose was shifted from subsite -2 to +2 in the wild-type to subsite -3 to +1 in the R171K mutant. Significant differences in product formation after manno-oligosaccharide incubation showed that the wild-type enzyme can perform transglycosylation on to saccharide acceptors while the R171K mutant cannot, likely due to loss of acceptor affinity. Interestingly, both enzymes show the ability to perform alcoholysis reactions with methanol and butanol, forming new beta-linked glyco-conjugates. Furthermore, it appears that the wild-type enzyme produces mainly mannobiose conjugates using M-4 as substrate, while in contrast the R171K mutant produces mainly mannotriose conjugates, due to the altered subsite binding