搭载人类自体干细胞的纤维支架及其在软组织再生中的应用

文章介绍了搭载人类自体干细胞的纤维支架技术及其在软组织再生中的应用优势。选用藻酸盐材料结合人体干细胞搭载关键技术制成的纤维支架,同时具有促进血管再生和触发成脂分化的能力。     

A framework for local and regional energy system integration between industry and municipalities—Case study UPM-Kymmene Kaukas

The integration of different energy systems, e.g., industrial and municipal, is potentially important for the efficient utilization of energy. It is important that the tools for analysing this type of integration can handle the energy systems on different levels, e.g., regional, site, plant and process levels. In this work, a framework for investigating the cost-efficient integration of large-scale energy systems is presented and tested at the UPM-Kymmene Kaukas pulp and paper plant and in the municipality of Lappeenranta, Finland. In addition to the different levels, the framework also aims to take into account several sub-problems, e.g., fuel logistic, optimal heat exchanger network and overall efficiency versus flexibility. The case in question shows that the presented framework can be used as a systematic tool for analysing the potential of integrating large energy systems and that it is able to handle both the synthesis of flexible heat exchanger networks and analyse the cost-efficiency of changes to the existing systems.     

Use of adipose stem cells and polylactide discs for tissue engineering of the temporomandibular joint disc

There is currently no suitable replacement for damaged temporomandibular joint (TMJ) discs after discectomy. In the present study, we fabricated bilayer biodegradable polylactide (PLA) discs comprising a non-woven mat of poly(L/D)lactide (P(L/D)LA) 96/4 and a P(L/DL)LA 70/30 membrane plate. The PLA disc was examined in combination with adipose stem cells (ASCs) for tissue engineering of the fibrocartilaginous TMJ disc in vitro. ASCs were cultured in parallel in control and chondrogenic medium for a maximum of six weeks. Relative expression of the genes, aggrecan, type I collagen and type II collagen present in the TMJ disc extracellular matrix increased in the ASC-seeded PLA discs in the chondrogenic medium. The hypertrophic marker, type X collagen, was moderately induced. Alcian blue staining showed accumulation of sulphated glycosaminoglycans. ASC differentiation in the PLA discs was close to that observed in pellet cultures. Comparison of the mRNA levels revealed that the degree of ASC differentiation was lower than that in TMJ disc-derived cells and tissue. The pellet format supported the phenotype of the TMJ disc-derived cells under chondrogenic conditions and also enhanced their hyalinization potential, which is considered part of the TMJ disc degeneration process. Accordingly, the combination of ASCs and PLA discs has potential for the development of a tissue-engineered TMJ disc replacement.     

Test-taking behaviors in a neurocognitive assessment: Associations with school-age outcomes in a Finnish longitudinal follow-up.

Test-taking behaviors (i.e., task focus, maintenance of attention, and cooperation) affect children's cognitive test performance, and, thus, it is critical to take test-taking behavior into account when drawing conclusions and making recommendations. Prior studies have evaluated test-taking behaviors at the end of the assessment; the present study focused on the fluctuation of cooperation and attention during a neuropsychological assessment. We examined the attention and cooperation of 5-year-old children in a test-taking situation; the associations between these aspects of their test-taking behavior and the children's concurrent neurocognitive test performance, IQ, and parent-rated behavior; and the associations with their IQ, behavioral outcomes, and academic achievement at 8 years of age. The data (for 76 boys and 63 girls) were drawn from the Jyv?skyl? Longitudinal Study of Dyslexia (Lyytinen et al., 2001, 2004). All the children were Caucasian and spoke Finnish as their native language. As a whole, the 5-year-old children showed high cooperation and attention, but a slight decrement in test-taking behavior toward the end of the session was rather common. Three subgroups of children with different levels of cooperation and attention were identified. Children in the subgroup with nonoptimal attention and cooperation showed decreasing neurocognitive test performance toward the end of the assessment session. They also showed more inattentive behavior 3 years later. The findings imply that the examiner's observations of waning attention and cooperation during the assessment session are highly relevant, as these provide stable and clinically meaningful information about the child's behavioral tendencies. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Experimental studies for verification of thermal effects in cutting

Investigations on metal-cutting machining processes that were conducted since the second half of the twentieth century have considerably contributed to disclosing the principles underlying the cutting process. Although numerous studies have been carried out on this subject, a generally valid model of the cutting process and the interactions in the separating processes does not exist yet. Such a model could guarantee the disclosure of the principles of thermodynamic interactions between the cutting process and the involved machine structure. This contribution is twofold and presents an experimental setup used to determine cutting forces and temperatures in orthogonal cutting processes. The results are then used as a reference for simulations made with the Discrete Element Method (DEM). The DEM is due to its meshless nature well suited to capture large deformations and rupture of material which is included very naturally. It is examined to which extent the measured results can be captured with the DEM model.     

Simultaneous heat exchanger network synthesis for direct and indirect heat transfer inside and between processes

Process plants are typically divided into different process parts having specific processing tasks with possibly different ownership. Heat integration between these processes can increase the energy- and economic efficiency for both the overall plant and the individual processes. In this paper we present a heat exchanger network synthesis MINLP-model that allows simultaneous heat integration directly between streams in the same process and both directly and indirectly between streams in different processes. The indirect heat transfer is accomplished by using intermediate streams. Two examples, one small explanatory one and one from the literature, are optimized. The results verify that the model works logically.     

Role of microbes in controlling the speciation of arsenic and production of arsines in contaminated soils

The influence of microbes on the speciation of arsenic and production of arsines in contaminated soils was investigated under laboratory conditions. Microbes were able to carry out reactions that resulted in changes in the speciation of arsenic in soil. The transformation of soil dominating species, arsenate [As(V)], under both aerobic and anaerobic conditions to arsenite [As(III)], monomethylarsonic acid [MMAA], dimethylarsinic acid [DMAA] and to volatile trimethylarsine [TMA] was, however, less than 0.5%, of which the production of TMA represented 0.02-0.3%. The volatilization process was also verified in the field, in the soil of a dumping area. The 'life-time' of arsines in air was, however, short and they were rapidly converted back to water soluble species, As(V) and trimethyl arsine oxide (TMAO).     

Strength retention of drawn self-reinforced polyglycolide rods and fixation properties of the distal femoral osteotomies with these rods. An experimental study on rats

Drawn self-reinforced polyglycolide (SR-PGA) rods, Ø 2 mm and 26 mm long, were implanted in the dorsal subcutaneus tissue of 16 rats. Osteotomies of the distal femur were fixed with SR-PGA rods (2 mm by 15 mm) in another 38 rats. The follow-up times varied from one week to one year. After sacrifice, three-point bending and shear tests were performed for subcutaneously placed rods. Radiological, histological, histomorphometrical, microradiographic, and oxytetracycline-fluorescence studies of osteotomized and intact control femora were also performed. At three weeks the flexural strength of the rods was 50% of the initial value, and the flexural modulus was 46% of the initial value. Five osteotomy specimens had to be excluded due to dislocation or non-union. One of the 33 evaluated osteotomy specimens showed signs of postoperative infection. Thirty-two osteotomies healed uneventfully. No gross signs of inflammatory or foreign-body reaction were observed. The amount of osteoid surface and active osteoid formation surface reached their highest value in the histomorphometrical analysis at 24 weeks. The present investigation demonstrated that the mechanical strength and fixation properties of the drawn SR-PGA rods are suitable for fixation of cancellous bone osteotomies in rats. The present article is the first report on the successful application of drawn SR-PGA rods for fixation of cancellous bone osteotomies.     

Interpersonal violations,speeding violations and their relation to accident involvement in Finland

The aim of the present study was to replicate the distinction between errors, lapses and violations, and to identify aggressive violations from normal or highway code violations. Furthermore, the relationship of these behaviours with road traffic accidents was examined. A total number of 1126 Finnish drivers completed a questionnaire containing the Driver Behaviour Questionnaire (DBQ) with extended violations scale, and questions regarding background information, such as age, gender and mileage. Also, questions about previous accidents and fines were asked. Factor analysis showed that a four-factor structure seemed more appropriate than the earlier established three-factor structure. The four factors were errors, lapses, speeding violations and interpersonal violations. The two types of violations result from different motives, and seem to be associated with different kinds of affect. Both interpersonal and speeding violations were reported most by young males, which was consistent with earlier findings. Logistic regression analyses indicated that errors predicted active accident involvement after partialling out the effects of demographic variables, whereas interpersonal violations were positively related to involvement in passive accidents. This was presumably due to different reporting tendencies of respondents. Speeding tickets were predicted by speeding and interpersonal violations and lapses and penalties for speeding by both kinds of violations and errors. Penalties for speeding, parking and other offences were predicted by interpersonal violations. The implications of these results are discussed.