481 research outputs found
Phytotoxicity of silver nanoparticles to aquatic plants, algae and micro-organisms
No full textSilver nanoparticles (Ag NPs) can easily leak into the aquatic environment and, depending on the environmental conditions, readily transform. Since ionic silver is considered one of the most toxic ions for aquatic organisms, there is a growing concern about the effects of Ag NPs on the aquatic ecosystem. Aquatic organisms are very sensitive to pollutants, but the fate and concentrations of Ag NPs in water are still unknown. Data shows that even low concentrations of Ag NPs could affect aquatic photosynthetic organisms, and the size and shape of nanoparticles plays a central role in Ag NP toxicity. Ag NP toxicity is not fully attributable to released ions: many studies show that in photosynthetic organisms silver ions and Ag NPs caused similar effects, although silver ions were often active at lower concentrations. Toxicity of Ag NPs may be caused by a Trojan-horse type of mechanism, in which nanoparticles are internalized within cells where they can release silver ions.
In photosynthetic aquatic organisms, one of the main targets of Ag NPs is the photosynthetic apparatus. AgNPs can also lead to an increase in oxidative stress through reactive oxygen species production. Ag NPs can modify the composition of a natural community of aquatic microorganisms, such as phytoplankton, and accumulate in the food chain, even if the potential for their biomagnification remains unclear
Long-term diffusion factors of technological development - an evolutionary model and case study
No full textIn the first part of this article, a short description of the most popular models of two competing technologies (the Fisher-Pry model and its modifications proposed by Blackman, Floyd, Sharif and Kabir) and the multi technological substitution models of Peterka and Marchetti-Nakiæenoviæ are presented. In the second section, we describe an evolutionary model of diffusion processes based on biological analogy, together with the method of its parameters’ identification using real data on technologies development. In the final sections the applications of that model to describe the real diffusion processes (namely, primary energy sources in the world energy consumption and the raw steel production in the United States) are presented. The feasibility of using the model to predict future shares of given technologies and to build alternative scenarios of future evolution of structure of the market is suggested.diffusion; substitution; evolution; simulation; s-curve; logistic curve; logistic function
Bacterial DNA is associated with tunnel widening in failed ACL reconstructions
No full textPurpose: To determine if tunnel widening, defined as change in maximal tunnel diameter from the time of initial bone tunnel drilling to revision surgery is associated with bacterial deoxyribonucleic acid (DNA) presence and concentration in torn graft tissue from failed anterior cruciate ligament reconstructions (ACLRs). Methods: Thirty-four consecutive revision ACLRs were included (mean age 27.3 years SD 10.9; median time to failure 4.9 years range 105 days–20 years). Graft selection of the failed reconstruction was 68% autograft, 26% allograft, and 6% autograft/allograft hybrid with a mean drilled tunnel diameter of 8.4 mm SD 0.8. Maximal tunnel diameters prior to revision were measured on pre-operative three-dimensional imaging and compared to drilled tunnel diameters at the time of the previous reconstruction. Tissue biopsies of the failed graft were obtained from tibial, femoral, and intraarticular segments. Sterile water left open to air during revision ACLRs and tissue from primary ACLRs were used as negative controls. Clinical cultures were obtained on all revision ACLRs and PCR with universal bacterial primer on all cases and negative controls. Fluorescence microscopy was used to confirm the presence and location of biofilms in two patients with retrieved torn graft tissue and fixation material. Amount of tunnel widening was compared to bacterial DNA presence as well as bacterial DNA concentration via Welch ANOVA. Results: Bacterial DNA was present in 29/34 (85%) revision ACLRs, 1/5 (20%) of primary ACLR controls and 0/3 (0%) sterile water controls. Cultures were positive (coagulase negative Staphylococcus sp.) in one case, which also had the greatest degree of tunnel widening. Femoral widening was greater in cases with detectable bacterial DNA (mean widening 2.6 mm SD 3.0) versus without (mean 0.3 mm SD 0.6) (p = 0.003) but was unaffected by bacterial DNA concentration (p = 0.44). Tibial widening was not associated with the presence of bacterial DNA (n.s.); however, higher bacterial DNA concentrations were observed in cases with tibial widening ≥ 3.0 mm (median 2.47 ng bacterial DNA/µg total DNA) versus widening < 3.0 mm (median 0.97 ng bacterial DNA/µg total DNA) (p = 0.046). Tunnel widening was not associated with time to failure, graft selection, or number of prior surgeries (n.s., all comparisons). Fluorescence microscopy confirmed the presence of biofilms on ruptured tendon graft as well as fixation material in 2/2 cases. Conclusion: Bacterial DNA is commonly encountered on failed ACLR grafts and can form biofilms. Bacterial DNA does not cause clinically apparent infection symptoms but is associated with tunnel widening. Further research is needed to determine whether graft decontamination protocols can reduce graft bacterial colonization rates, ACLR tunnel widening or ACLR failure risk. Level of evidence: Therapeutic III.</p
Myeloid neoplasms arising after methotrexate therapy for autoimmune rheumatological diseases do not exhibit poor-risk molecular features
No full textCorrespondenceMihir D. Wechalekar, Lin-Pierre Zhao, Monika M. Kutyna, Lih En Hong, Joule Li, Kevin Hung, Hamish S. Scott, Anna Brown, Christopher C. Hahn, Karin Kassahn, Dariusz Ladon, David T. Yeung, Daniel Thomas, Mrinal Patnaik, Susanna Proudman, Lionel Ades, Mithun V. Shah, Chung H. Kok, and Devendra K. Hiwas
RBC-transfusion dependency improves the prognostic value of the revised-IPSS in MDS patients: analysis of South Australian and Dusseldorf MDS registries
No full textPublished online December 1, 2016.Deepak Singhal, Corinna Strupp, Rakchha Chhetri, Monika M Kutyna, L Amilia Wee, Shriram V. Nath, Nicholas Wickham, Chi-hung Hui, James X Gray, David M. Ross, Ian D Lewis, Peter G Bardy, John Reynolds, Luen Bik To, Devendra K Hiwase, and Ulrich Germin
On the growth and best polynomial approximation of entire functions in C m ( m ≥ 2 ) in some Banach spaces
No full textSelective escalation of imatinib therapy and early switching to nilotinib in de novo chronic phase CML patients: interim results from the TIDELL-II trial
No full textOral session ASH Annual Meeting Abstracts: 52nd Annual Meeting of the American Society of Hematology (ASH), Orlando, FL, December 4-7, 2010David T. Yeung, Michael Osborn, Deborah L. White, Susan Branford, Lauren Haswell, Cassandra Slader, Samar Issa, Devendra K. Hiwase, Mark S. Hertzberg, Anthony P. Schwarer, Robin Filshie, Christopher K. Arthur, Yiu Lam Kwan, Cecily J. Forsyth, David M. Ross, Anthony K. Mills, Andrew Grigg and Timothy Hughes and on behalf of ALLGhttp://abstracts.hematologylibrary.org/content/vol116/issue21
Feed resource development from agro-industrial by-products and their efficient utilisation in South East Asia and the Pacific
No full textMeeting: Regional Seminar on Management and Utilisation of Agricultural and Industrial Wastes, 21-23 Mar. 1990, Kuala Lumpur, M
Nutrition of and feeding strategies for improving productivity in buffalo genotypes
No full textMeeting: International Symposium on Buffalo Genotypes for Small Farms in Asia, 15-19 May 1989, Kuala Lumpur, M
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