207 research outputs found
Technical tip: high-resolution isolation of nanoparticle–protein corona complexes from physiological fluids
Full text linkNanoparticles (NPs) in contact with biological fluids are generally coated with environmental proteins, forming a stronger layer of proteins around the NP surface called the hard corona. Protein corona complexes provide the biological identity of the NPs and their isolation and characterization are essential to understand their in vitro and in vivo behaviour. Here we present a one-step methodology to recover NPs from complex biological media in a stable non-aggregated form without affecting the structure or composition of the corona. This method allows NPs to be separated from complex fluids containing biological particulates and in a form suitable for use in further experiments. The study has been performed systematically comparing the new proposed methodology to standard approaches for a wide panel of NPs. NPs were first incubated in the biological fluid and successively recovered by sucrose gradient ultracentrifugation in order to separate the NPs and their protein corona from the loosely bound proteins. The isolated NP–protein complexes were characterized by size and protein composition through Dynamic Light Scattering, Nanoparticle Tracking Analysis, SDS-PAGE and LC-MS. The protocol described is versatile and can be applied to diverse nanomaterials and complex fluids. It is shown to have higher resolution in separating the multiple protein corona complexes from a biological environment with a much lower impact on their in situ structure compared to conventional centrifugal approaches
Internationalization of a health care mobile application : Case study of Onerva Hoivaviestintä Oy
Full text linkCompanies have been trying to increase their footprint and target a bigger market share, by internationalising. It has been a global trend not just among corporations but also on the level of society.
The following research paper is a case study for Onerva Hoivaviestintä Oy, which is a start-up company. The company connects family members of elderly and the care providers. Due to COVID-19 pandemic it is harder for relatives to see their elderly family members, therefore applications like Onerva is demanded. To gain new opportunities and to expand their business they are obligated to internationalise and target foreign markets. Prior to new market entry it is recommended to analyse potential market areas, as it lowers the risk and shows which countries could bring higher and stable profit.
This research was pursued to compare Denmark’s, Sweden’s and Germany’s market suitability for a new instant-messaging application targeted for elderly care. The market study was completed by analysing macroenvironment and microenvironment factors in the chosen countries. The researcher put macroenvironmental factors in focus for the literature review chapter, since the application concept is innovative and there has not been any similar data collected in this topic.
The nature of the research is exploratory. The author selected mixed methods approach to support the theory. Firstly, numerical secondary data was collected from other researchers, then with the interviews, the author proved with primary qualitative data the hypothesis. The interviews were carried out with three elderly home workers from Denmark, Germany and Sweden. The interviews were semi structured, as the author wanted to have a deep understanding of the country’s elderly health care system.
Comparing all the secondary and primary data, the researcher concluded that due to the technological advancement and number of potential users. The most reasonable market for Onerva Hoi-vaviestintä company, to expand their business first is Sweden
CINEMATOGRAPHIC STYLE PROBLEMS (According to Bela Balazs point of view)
No full textCinematographic style is started in large scale to apply changes, by including the technological achievements that now are greater and indivisible in the world of film art. People dealing with film even today are experimenting on their genre and styles by selecting different topics and treating with a professional and boldness approach.
In this piece of work we will treat the approach and point of view of the great thinker and philosopher Bela Balazs, that in his important book “Filmkultura”, a great part has left for cinematographic style problems. It is important for us to see how he as treated the cinematographic style problems. Taking in consideration the time and the technological achievements at the time that author has been living, freely we can cast that with a great professionality he brings out and arguments genuine theories of the world of film art, those that even now have place for usage
Butyrylated starch protects colonocyte DNA against dietary protein-induced damage in rats
No full textCopyright © The Author 2008. Published by Oxford University Press. All rights reserved.Dietary resistant starch (RS), as a high amylose maize starch (HAMS), prevents dietary protein-induced colonocyte genetic damage in rats, possibly through the short-chain fatty acid (SCFA) butyrate produced by large bowel bacterial RS fermentation. Increasing butyrate availability may improve colonic health and dietary high amylose maize butyrylated starch (HAMSB) is an effective method of achieving this goal. In this study, rats (n = 8 per group) were fed diets containing high levels (25%) of dietary protein as casein with 10 or 20% dietary HAMSB and HAMS. Colonocyte genetic damage was measured by the comet assay and was 2-fold higher in rats fed 25% protein than those fed 15% protein (P < 0.001). Concurrent feeding of 25% protein and either HAMS or HAMSB lowered genetic damage significantly relative to a low-RS high-protein control diet. The 20% HAMSB diet was twice as effective as 20% HAMS in opposing genetic damage. Large bowel digesta butyrate was significantly increased in rats fed 20% compared with 10% HAMS and in rats fed 20% compared with 10% HAMSB. The levels were significantly higher in the HAMSB groups relative to the HAMS groups. Hepatic portal venous SCFA were higher in rats fed HAMS and highest in those fed HAMSB. Caecal digesta ammonia was increased by HAMSB and correlated negatively with digesta pH. Ammonia is cytotoxic and lower digesta pH could lower its absorption, possibly contributing to lower genetic damage. Delivery of butyrate to the large bowel by HAMSB could reduce colorectal cancer risk by preventing diet-induced colonocyte genetic damage.Balazs H. Bajka, Julie M. Clarke, Lynne Cobiac and David L. Toppin
Use of the 13C-sucrose breath test to assess chemotherapy-induced small intestinal mucositis in the rat
No full textMucositis is a debilitating side-effect of chemotherapy which affects the mucosa of the gastrointestinal tract, particularly the small intestine. Currently there are no simple, non-invasive methods to detect and monitor small intestinal function and the severity of mucosal damage. Activity of the brush-border enzyme sucrase provides an indicator of small intestinal absorptive function that remains relatively constant throughout life. Measuring 13CO-2 levels in expired breath following ingestion of 13C-sucrose is a non-invasive marker of total intestinal sucrase activity. We evaluated the sucrose breath test (SBT) as an indicator of small intestinal injury and dysfunction, utilizing a rat model of chemotherapy-induced mucositis. SBT results reflected the time-course of damage and repair after methotrexate (MTX) treatment, with damage most severe 72 h after chemotherapy, and repair commencing after 96 h. SBT results correlated significantly with jejunal sucrase activity determined biochemically (r2=0.89; p<0.005). Moreover, calcium folinate ingested prior to chemotherapy totally prevented damage to the small intestinal mucosa induced by MTX, as assessed by the SBT in concert with structural, and biochemical indices. The SBT provides a simple, non-invasive, integrated measure of small intestinal damage and function. The SBT holds significant potential to monitor small intestinal function in cancer patients undergoing chemotherapy. This technique possesses further applicability to the screening of newly-developed agents for potential gastrointestinal toxicity including the development of new therapies targeted at minimising or preventing the onset of chemotherapy-induced mucositis.Julie M. Clarke, Nicole C Pelton, Balazs H. Bajka, Gordon S. Howarth, Leanna C. Read and Ross N. Butle
The effects of increased butyrate delivered as butyrylated starch on large bowel physiology in the rat.
Full text linkIntroduction: Short chain fatty acids (SCFA) are produced by large bowel fermentation of dietary carbohydrates including resistant starch (RS) and non-starch polysaccharides (NSP). SCFA (particularly butyrate) play a major role in maintaining large bowel function and may reduce the incidence of colonic disease. Butyrate is the preferred metabolic substrate of colonocytes and is believed to play a key role in modulating epithelial cell cycle, mucosal immune response and gut motility. Increasing large bowel butyrate supply requires intakes of NSP or (RS) much higher than those currently consumed in western diets. Recent studies have shown large bowel butyrate is increased by the ingestion of butyrylated starch but the characteristics and physiological effects of its ingestion in animal models of colonic disease have not yet been investigated.
Aims and Methods: The experiments in in vitro and in rats described in this thesis examined: the effects of production techniques and cooking on the capacity of butyrylated starch to deliver butyrate to the large bowel. They investigated the effects of increased butyrate levels on large bowel function in: (i) normal rats, (ii) the dextran sulphate sodium (DSS) rat model of ulcerative colitis (UC) and (iii) the high dietary protein rat model of colonocyte genetic damage.
Results: Starch type, pre-treatment and the degree of butyrylation influenced the in vitro digestion and fermentation characteristics of butyrylated starch before and after cooking. Butyrylated starch was less susceptible to small intestinal digestion RS as than high amylose maize starch (HAMS) in vitro. Feeding diets containing 10% cooked butyrylated starch delivered significantly greater amounts of butyrate to the large bowel of rats than 10% raw or cooked HAMS. Butyrate did not influence colonocyte proliferation throughout the large bowel of the rat but increased distal colonic IL-18 concentrations and decreased longitudinal smooth muscle contractility. Feeding HAMS or butyrylated HAMS (HAMSB) to rats during DSS induced UC and during 7 days of recovery resulted in increased mucosal damage compared to low amylose maize starch (LAMS) fed rats. When rats were fed HAMS or HAMSB during the 7 days of recovery only, there was no significant difference in mucosal damage. Genetic damage, as measured by the comet assay, was 2 fold higher in rats fed high protein diet compared with those fed a low protein diet. Concurrent feeding of high protein and either HAMS or HAMSB resulted in significantly less genetic damage. Genetic damage in rats fed 20% HAMSB was half the levels of the 20% HAMS group, and was the same as the low protein diet.
Conclusions: Butyrylated starch delivered butyrate to the large bowel in rats effectively, was less susceptible to small intestinal digestion and had greater stability following cooking than the unmodified base starch. Increased digesta butyrate did not affect large bowel function or colonocyte proliferation in the normal rat; the effects on mucosal damage in the DSS rat model of ulcerative colitis were inconclusive. Increased luminal butyrate prevented high-protein induced colonocyte genetic damage. Butyrylated starches have potential to assist with the maintenance of bowel health and to contribute to reduced risk of colonic disease in the community.Thesis (Ph.D.) -- University of Adelaide, School of Molecular and Biomedical Science, 200
Butyrylated starch is less susceptible to enzymic hydrolysis and increases large-bowel butyrate more than high-amylose maize starch in the rat
Full text linkLarge-bowel fermentation of resistant starch produces SCFA that are believed to be important in maintaining visceral function. High-amylose maize starch (HAMS) and acylated starches are sources of resistant starch and are an effective means of increasing colonic SCFA. Cooking increases digestibility of starches but its effects on the capacity of these starches to raise large-bowel SCFA are unknown. We have examined the effects of cooking of HAMS and butyrylated HAMS (HAMSB) on amylolysis in vitro and their capacity to raise caeco-colonic SCFA in rats. The starches were boiled in excess water and microwaved, followed by drying at 100°C. Cooking increased in vitro glucose release for both starches but significantly less from HAMSB. Rat growth rates were unaffected when fed cooked resistant starch. Digesta pH was increased in the caecum and proximal colon of rats fed cooked HAMS. Distal colonic pH was highest in rats fed cooked HAMSB. Factorial analyses (2×2) of caecal SCFA pools showed significant differences between HAMS and HAMSB, and that cooking significantly lowered caecal butyrate pools. Portal venous butyrate concentrations were higher in both HAMSB groups than those fed HAMS. The data suggest that HAMSB is less susceptible to in vitro amylolysis than HAMS following cooking and delivers more butyrate to rat caecum than HAMS. This attribute may be useful in food applications for specific delivery of SCFA to the colon. Preparation of carbohydrates to simulate human food in animal experiments may be important to assess nutritional and physiological effects accurately.Balázs H. Bajka, David L. Topping, Lynne Cobiac and Julie M. Clark
Improving Operational Intensity in Data Bound Markov Chain Monte Carlo
No full textTypically, parallel algorithms are developed to leverage the processing power of multiple processors simultaneously speeding up overall execution. At the same time, discrepancy between \{DRAM\} bandwidth and microprocessor speed hinders reaching peak performance. This paper explores how operational intensity improves by performing useful computation during otherwise stalled cycles. While the proposed methodology is applicable to a wide variety of parallel algorithms, and at different scales, the concepts are demonstrated in the machine learning context. Performance improvements are shown for Bayesian logistic regression with a Markov chain Monte Carlo sampler, either with multiple chains or with multiple proposals, on a dense data set two orders of magnitude larger than the last level cache on contemporary systems.Part of the work presented in this paper was funded by Johnson & Johnson. This project has received funding from the European Union’s Horizon 2020 Research and Innovation programme under Grant Agreement no. 671555
Quantification of Concrete-Concrete Interface Strength – A Review
No full textThe construction industry is experiencing a significant increase in hybrid concrete structures due to the need for repairing/strengthening of existing structures and the development of novel hybrid structures. The crack development and the ultimate capacity of hybrid concrete structures may significantly be governed by the properties of interface between the two concretes, making the quantification of interface properties essential. A large number of bond tests have been reported in literature but most of them do not result in a failure directly/entirely at the interface (unless the interface is very weak), resulting in only a lower bound estimate of the interfacial strength. Furthermore, the reported interfacial properties are only determined from small-scale bond tests where structural effects (like shrinkage) are limitedly taken into account. In the current study, the most commonly used bond tests are critically assessed in terms of the stress distribution caused by their inherent boundary conditions. Furthermore a testing procedure is then discussed which can allow for the quantification of the interfacial properties. A possible structural test is also designed which forces the failure to localize at the interface and allows to determine interface properties considering structural effects.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Concrete StructuresMaterials and Environmen
A critical review on structural behavior of alkali-activated concrete beams
No full textThe increasing demand for sustainable development in engineering practice has triggered researchers to explore solutions to reduce the CO2 footprint caused by ordinary Portland cement (OPC) production. Alkali-activated concrete (AAC), made of by-products using alkali activation, is of great potential as a promising alternative to conventional concrete (CC). Despite vast studies on its material properties, there is still insufficient scientific research on the structural performance of AAC, which impedes its widespread application. In this paper, an overview of the fundamental behavior of AAC beams under different loading conditions is presented. The experimental investigations on mechanical performance of AAC beams are reviewed in terms of ultimate capacity, ductility and cracking behavior. Moreover, numerical methods to predict AAC structural response as well as the applicability of existing CC design codes are summarized. It is concluded that AAC beams show comparable short-term behavior with CC counterparts. Besides, the design codes for CC turn out to be applicable but conservative for most steel-reinforced AAC beams. Though short-term flexural behavior has been widely investigated for AAC beams, the challenge remains to clarify shear behavior and long-term behavior. Furthermore, reliable guidelines are needed to be developed, providing recommendations for future structural design.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Concrete Structure
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