14 results on '"Becker, Klaus"'
Search Results
2. Pharmaceutical potential of phorbol esters from Jatropha curcas oil.
- Author
-
Devappa, RakshitK., Malakar, ChandiC., Makkar, HarinderP.S., and Becker, Klaus
- Abstract
Phorbol esters (PEs) are diterpenes present in Jatropha curcas L. seeds and have a myriad of biological activities. Since PEs are toxic, they are considered to be futile in Jatropha-based biodiesel production chain. In the present study, the extracted PEs from Jatropha oil were used as a starting material to synthesise pharmacologically important compound, prostratin. The prostratin synthesised from Jatropha showed identical mass with that of the reference standard prostratin, as determined by Nano-LC-ESI-MS/MS. Considering the rapid growth in Jatropha biodiesel industry, potential exists to harness large amount of PEs which can be further utilised to synthesise prostratin as a value added product. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
3. Dietary roles of non-starch polysaccharides in human nutrition: a review.
- Author
-
Kumar V, Sinha AK, Makkar HP, de Boeck G, Becker K, Kumar, Vikas, Sinha, Amit K, Makkar, Harinder P S, de Boeck, Gudrun, and Becker, Klaus
- Abstract
Nonstarch polysaccharides (NSPs) occur naturally in many foods. The physiochemical and biological properties of these compounds correspond to dietary fiber. Nonstarch polysaccharides show various physiological effects in the small and large intestine and therefore have important health implications for humans. The remarkable properties of dietary NSPs are water dispersibility, viscosity effect, bulk, and fermentibility into short chain fatty acids (SCFAs). These features may lead to diminished risk of serious diet related diseases which are major problems in Western countries and are emerging in developing countries with greater affluence. These conditions include coronary heart disease, colo-rectal cancer, inflammatory bowel disease, breast cancer, tumor formation, mineral related abnormalities, and disordered laxation. Insoluble NSPs (cellulose and hemicellulose) are effective laxatives whereas soluble NSPs (especially mixed-link β-glucans) lower plasma cholesterol levels and help to normalize blood glucose and insulin levels, making these kinds of polysaccharides a part of dietary plans to treat cardiovascular diseases and Type 2 diabetes. Moreover, a major proportion of dietary NSPs escapes the small intestine nearly intact, and is fermented into SCFAs by commensal microflora present in the colon and cecum and promotes normal laxation. Short chain fatty acids have a number of health promoting effects and are particularly effective in promoting large bowel function. Certain NSPs through their fermented products may promote the growth of specific beneficial colonic bacteria which offer a prebiotic effect. Various modes of action of NSPs as therapeutic agent have been proposed in the present review. In addition, NSPs based films and coatings for packaging and wrapping are of commercial interest because they are compatible with several types of food products. However, much of the physiological and nutritional impact of NSPs and the mechanism involved is not fully understood and even the recommendation on the dose of different dietary NSPs intake among different age groups needs to be studied. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
4. Jatropha Toxicity—A Review.
- Author
-
Devappa, Rakshit K., Makkar, Harinder P. S., and Becker, Klaus
- Subjects
JATROPHA ,PHANEROGAMS ,VEGETABLE oils as fuel ,BIODIESEL fuels ,PLANT extracts ,CHEMICAL composition of plants ,INDUSTRIAL safety ,PHARMACEUTICAL industry - Abstract
Jatropha is a nonedible oil seed plant belonging to Euphorbiaceae family. Global awareness of sustainable and alternative energy resources has propelled research on Jatropha oil as a feedstock for biodiesel production. During the past two decades, several cultivation projects were undertaken to produce Jatropha oil. In future, the increased cultivation of toxic Jatropha plants and utilization of its agro-industrial by-products may raise the frequency of contact with humans, animals, and other organisms. An attempt was thus made to present known information on toxicity of Jatropha plants. The toxicity of Jatropha plant extracts from fruit, seed, oil, roots, latex, bark, and leaf to a number of species, from microorganisms to higher animals, is well established. Broadly, these extracts possess moluscicidal, piscicidal, insecticidal, rodenticidal, antimicrobial, and cytotoxic properties, and exert adverse effects on animals including rats, poultry, and ruminants. The toxicity attributed to these seeds due to their accidental consumption by children is also well documented. An attempt was also made to identify areas that need further study. The information provided in this review may aid in enhancing awareness in agroindustries involved in the cultivation, harvesting, and utilization of Jatropha plants and its products with respect to the potential toxicity of Jatropha, and consequently in application and enforcement of occupational safety measures. Data on the wide range of bioactivities of Jatropha and its products were collated and it is hoped will create new avenues for exploiting these chemicals by the phamaceutical industry to develop chemotherapeutic agents. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
5. Phorbol Esters: Structure, Biological Activity, and Toxicity in Animals.
- Author
-
Goel, Gunjan, Makkar, Harinder P. S., Francis, George, and Becker, Klaus
- Subjects
PHORBOL esters ,TETRACYCLINES ,TUMORS ,DIGLYCERIDES ,PROTEIN kinases ,ANTI-infective agents ,BIOPESTICIDES ,INSECTICIDES ,DETOXIFICATION (Substance abuse treatment) ,HYDROCYANIC acid - Abstract
Phorbol esters are the tetracyclic diterpenoids generally known for their tumor promoting activity. The phorbol esters mimic the action of diacyl glycerol (DAG), activator of protein kinase C, which regulates different signal transduction pathways and other cellular metabolic activities. They occur naturally in many plants of the family Euphorbiacaeae and Thymelaeaceae. The biological activities of the phorbol esters are highly structure specific. The phorbol esters, even at very low concentrations, show toxicological manifestations in animals fed diets containing them. This toxicity limits the use of many nutritive plants and agricultural by-products containing phorbol esters to be used as animal feed. Therefore, various chemical and physical treatments have been evaluated to extract or inactivate phorbol esters so that seed meals rich in proteins could be used as feed resources. However, not much progress has been reported so far. The detoxifying ability has also been reported in some molluscs and in liver homogenate of mice. Besides, possessing antinutritional and toxic effects, few derivatives of the phorbol esters are also known for their antimicrobial and antitumor activities. The molluscicidal and insecticidal properties of phorbol esters indicate its potential to be used as an effective biopesticide and insecticide. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
6. Dietary back-calculation using stable isotopes: can activities of enzymes involved in amino acid metabolism be used to improve estimates of trophic shifts in fish?
- Author
-
Gaye-Siessegger, Julia, Focken, Ulfert, Abel, Hansjörg, and Becker, Klaus
- Subjects
NILE tilapia ,CARBON isotopes ,NITROGEN isotopes ,ENZYMOLOGY ,ASPARTATE aminotransferase ,DEHYDROGENASES ,LOW-protein diet ,AMINO acids ,REGRESSION analysis - Abstract
The aim of this study was (1) to assess the effects of dietary protein content and feeding level on trophic shifts of C and N isotopes (Δ δ13Ctissue-diet and Δ δ15Ntissue-diet) and (2) to test whether the measurement of the activities of two enzymes involved in the metabolism of amino acids could improve the accuracy of estimation of the trophic shifts of C and N isotopes. For this, 36 Nile tilapia (Oreochromis niloticus) were kept under controlled conditions for 8 weeks and fed at three different levels (2, 4 and 8 g kg-0.8 d-1) with three diets differing in their protein content only (20, 29 and 39 %). For each fish, food to fish body trophic shifts of C and N isotopes were measured as well as the hepatic activities of aspartate aminotransferase (ASAT) and glutamate dehydrogenase (GDH). The feeding level affected the activities of ASAT and GDH as well as the trophic shifts of C and N isotopes significantly but the dietary protein content had no significant effect except on the specific activity of ASAT. Fish fed at the lowest level had significantly higher trophic shifts of C and N isotopes than fish fed at higher levels. The trophic shifts were significantly lower in fish with a high protein utilisation. Values of the 'goodness-of-fit' for linear regressions between enzyme activities and trophic shifts were low. Thus, activities of ASAT and GDH are not suitable for predicting estimates of trophic shifts in situations where the amount of food consumed or the dietary protein content is not known. In further studies, activities of enzymes involved in the metabolism of amino acids combined with measurements of the activities of other enzymes should be used to try and improve the accuracy of estimates of trophic shifts. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
7. Time-trends in the epidemiology of peptic ulcer bleeding.
- Author
-
Ohmann, Christian, Imhof, Michael, Ruppert, Christian, Janzik, Ulf, Vogt, Christoph, Frieling, Thomas, Becker, Klaus, Neumann, Frank, Faust, Stephan, Heiler, Klaus, Haas, Klaus, Jurisch, Rainer, Wenzel, Ernst-Günter, Normann, Stefan, Bachmann, Oliver, Delgadillo, Jorge, Seidel, Florian, Franke, Claus, Lüthen, Reinhard, and Yang, Qin
- Subjects
PEPTIC ulcer ,HEMORRHAGE ,ULCERS ,SUPPURATION ,NONSTEROIDAL anti-inflammatory agents ,ANTI-inflammatory agents - Abstract
Objective. Despite the introduction of effective medical treatment of peptic ulcer disease, bleeding is still a frequent complication. The aim of this study was to investigate whether the incidence and the risk profile of peptic ulcer haemorrhage have changed within a 10-year period. Material and methods. In a prospective epidemiological and observational study the incidence and risk profile of peptic ulcer haemorrhage in Dusseldorf, Germany were compared between two time periods (period A: 1.3.89-28.2.90 and period B: 1.4.99-31.3.2000), involving nine hospitals with both surgical and medical departments. Patients with proven peptic ulcer haemorrhage at endoscopy or operation were included in the study; those with bleeding under defined severe stress conditions were excluded. Results. No differences in bleeding ulcer incidence were observed between periods A and B (51.4 per 100,000 person-years versus 48.7), or for duodenal ulcer (24.9 versus 25.7) or for gastric ulcer bleeding (26.5 versus 23.0). A marked increase in incidence rates was observed with increasing age. In period B, patients with bleeding ulcers were older (56% versus 41% 70 years or older), were usually taking non-steroidal anti-inflammatory drugs (NSAIDs) (45% versus 27%) and were less likely to have a history of ulcer (25% versus 59%) compared with patients in period A. Conclusions. The persisting high incidence of peptic ulcer disease is a superimposing of two trends: a higher incidence in the growing population of elderly patient with a higher intake of NSAIDs and a lower incidence among younger patients due to a decrease in incidence and improved medical treatment. [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
- View/download PDF
8. th Annual Meeting of the German Association for Stable Isotope Research (GASIR) October, 6 to 8, 2003, Cologne, Germany">Dietary lipid content influences the activity of lipogenic enzymes in the liver and on whole body δ 13 c values of Nile tilapia, Oreochromis niloticus (L.)
- Author
-
Gaye-Siessegger, Julia, Focken, Ulfert, Abel, Hansjörg, and Becker, Klaus
- Subjects
STABLE isotopes ,CARBON ,DIET ,ENZYME activation ,FISHES - Abstract
The use of stable isotope techniques for the reconstruction of diets has increased over the last decade. However, isotopic ratios in an animal are not only affected by the composition of the feed, but also by the amount of feed consumed. An uncertainty of up to 1 ‰ for both δ 13 C and δ 15 N values has been observed when the feeding level is unknown. This may have substantial effects on the results of back-calculation. As the feeding level of animals is unknown in nature, an additional indicator for their nutritional status is needed. High feeding levels and a consequent surfeit of dietary energy lead to the synthesis of lipids. In order to test whether the level of lipogenesis could be used as an indicator, Nile tilapia ( Oreochromis niloticus ) were fed four isonitrogenous and isoenergetic wheat-based semi-synthetic diets with different lipid contents (2.0 %, 4.5 %, 9.5 % and 13.3 %) for eight weeks. Body composition, gross energy content and δ 13 C values in the lipids and the lipid-free material were determined in diets and fish bodies. The livers of three fish per feeding group were assayed for the activity of two lipogenic enzymes, ATP-citrate lyase and malic enzyme. There was a strong negative correlation between δ 13 C values in the lipids of the individual fish and the apparent lipid conversion. The activities of lipogenic enzymes decreased with rising lipid content in the diet. The δ 13 C values in the lipids decreased significantly with increasing specific activity for both enzymes. In this experiment where lipogenesis was influenced by the composition of the diet, it was possible to determine the exact value for the trophic shift in relation to the enzyme activities. Further experiments to investigate the use of enzyme activities in situations where the feeding level of an animal is unknown are recommended. * Revised version of a paper presented at the 26 th Annual Meeting of the German Association for Stable Isotope Research (GASIR) October, 6 to 8, 2003, Cologne, Germany [ABSTRACT FROM AUTHOR]
- Published
- 2004
- Full Text
- View/download PDF
9. Cumulant approach and coupled-cluster method for many-particle systems.
- Author
-
Becker, Klaus W. and Vojta, Matthias
- Subjects
- *
CLUSTER theory (Nuclear physics) , *ENERGY levels (Quantum mechanics) - Abstract
Cumulants represent a natural language for expressing macroscopic properties of many-body systems. The most important property of cumulants is that of size consistency, i.e. a cumulant expression for an extensive variable scales with the size of the system, independent of possible further approximations used in the evaluation procedure. Cumulants can be considered as a generalization of linked diagrams known from diagrammatic technique of many-body theory. In this paper we outline a recently introduced method based on cumulants in order to derive expressions for zero-temperature properties of many-particle systems, i.e. the ground-state energy, static expectation values and dynamical correlation functions. This cumulant formalism allows one to describe weakly and strongly correlated systems along the same lines. We show that the coupled-cluster method known from quantum chemistry can be derived from our cumulant approach. Finally, we demonstrate the usefulness of the cumulant method by applying it to examples from solid-state physics and quantum chemistry. [ABSTRACT FROM AUTHOR]
- Published
- 1998
- Full Text
- View/download PDF
10. Influence of substratum surface tension on biofouling of artificial substrata in Kiel Bay (Western Baltic): In situ studies.
- Author
-
Becker, Klaus and Wahl, Martin
- Abstract
The role of substratum surface tension on the colonization process (fouling) on artificial substrata was investigated in Kiel Bay (Western Baltic). The density of organisms from the major groups (bacteria, microalgae, protozoa, macroorganisms) was monitored on test panels after several exposure intervals in two experimental series. The results showed that substrata with a surface free energy of 24 mN/m were initially less densely colonized by representatives of the different fouling groups. The most hydrophobic substrata and those between 31–43 mN/m were heavily colonzied but there was a slight decrease in density towards the most hydrophilic material (glass). After an immersion time of 64 d these differences were not apparent for bacteria, microalgae or protozoa. These results correspond with thermodynamic predictions, which propose minimum bioadhesion on substrata with critical surface tensions between 20–25 mN/m in seawater. In addition, factors other than the surface tension may be important in marine fouling. [ABSTRACT FROM PUBLISHER]
- Published
- 1991
- Full Text
- View/download PDF
11. Educational Rehabilitation in the German Democratic Republic.
- Author
-
Becker, Klaus‐Peter and GROßE, Klaus‐Dietrich
- Abstract
AN OVERVIEW of educational rehabilitation of persons with disabilities in the German Democratic Republic is given. The authors describe the education system, the health and welfare services as well as the forms of training of special educators for persons with disabilities. The topics are discussed in the context of the theoretical background and of the current political changes in the country. [ABSTRACT FROM PUBLISHER]
- Published
- 1990
- Full Text
- View/download PDF
12. Carbon farming: the best and safest way forward?
- Author
-
Becker, Klaus and Lawrence, Peter
- Subjects
- *
CARBON , *WILLINGNESS to pay , *FARMS , *AGRICULTURAL technology - Abstract
Breathing space, carbon capture strategies, collateral benefits, democracy, desert greening, irrigation, willingness to pay. [Extracted from the article]
- Published
- 2014
- Full Text
- View/download PDF
13. Stimulated exoelectron emission from the surface of insulating solids.
- Author
-
Becker, Klaus
- Published
- 1972
- Full Text
- View/download PDF
14. Internation harmonization of nuclear and radiation standards and thefuture of nuclear energy
- Author
-
Becker, Klaus
- Subjects
NUCLEAR energy - Published
- 1989
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.