Subchronic oral toxicity of silver nanoparticles

<p>Abstract</p> <p>Background</p> <p>The antibacterial effect of silver nanoparticles has resulted in their extensive application in health, electronic, consumer, medicinal, pesticide, and home products; however, silver nanoparticles remain a controversial area of research with respect to their toxicity in biological and ecological systems.</p> <p>Results</p> <p>This study tested the oral toxicity of silver nanoparticles (56 nm) over a period of 13 weeks (90 days) in F344 rats following Organization for Economic Cooperation and Development (OECD) test guideline 408 and Good Laboratory Practices (GLP). Five-week-old rats, weighing about 99 g for the males and 92 g for the females, were divided into four 4 groups (10 rats in each group): vehicle control, low-dose (30 mg/kg), middle-dose (125 mg/kg), and high-dose (500 mg/kg). After 90 days of exposure, clinical chemistry, hematology, histopathology, and silver distribution were studied. There was a significant decrease (P < 0.05) in the body weight of male rats after 4 weeks of exposure, although there were no significant changes in food or water consumption during the study period. Significant dose-dependent changes were found in alkaline phosphatase and cholesterol for the male and female rats, indicating that exposure to more than 125 mg/kg of silver nanoparticles may result in slight liver damage. Histopathologic examination revealed a higher incidence of bile-duct hyperplasia, with or without necrosis, fibrosis, and/or pigmentation, in treated animals. There was also a dose-dependent accumulation of silver in all tissues examined. A gender-related difference in the accumulation of silver was noted in the kidneys, with a twofold increase in female kidneys compared to male kidneys.</p> <p>Conclusions</p> <p>The target organ for the silver nanoparticles was found to be the liver in both the male and female rats. A NOAEL (no observable adverse effect level) of 30 mg/kg and LOAEL (lowest observable adverse effect level) of 125 mg/kg are suggested from the present study.</p

Acidic pH shock induces the expressions of a wide range of stress-response genes

<p>Abstract</p> <p>Background</p> <p>Environmental signals usually enhance secondary metabolite production in <it>Streptomycetes </it>by initiating complex signal transduction system. It is known that different sigma factors respond to different types of stresses, respectively in <it>Streptomyces </it>strains, which have a number of unique signal transduction mechanisms depending on the types of environmental shock. In this study, we wanted to know how a pH shock would affect the expression of various sigma factors and shock-related proteins in <it>S. coelicolor </it>A3(2).</p> <p>Results</p> <p>According to the results of transcriptional and proteomic analyses, the major number of sigma factor genes were upregulated by an acidic pH shock. Well-studied sigma factor genes of <it>sigH </it>(heat shock), <it>sigR </it>(oxidative stress), <it>sigB </it>(osmotic shock), and <it>hrdD </it>that play a major role in the secondary metabolism, were all strongly upregulated by the pH shock. A number of heat shock proteins including the DnaK family and chaperones such as GroEL2 were also observed to be upregulated by the pH shock, while their repressor of <it>hspR </it>was strongly downregulated. Oxidative stress-related proteins such as thioredoxin, catalase, superoxide dismutase, peroxidase, and osmotic shock-related protein such as vesicle synthases were also upregulated in overall.</p> <p>Conclusion</p> <p>From these observations, an acidic pH shock was considered to be one of the strongest stresses to influence a wide range of sigma factors and shock-related proteins including general stress response proteins. The upregulation of the sigma factors and shock proteins already found to be related to actinorhodin biosynthesis was considered to have contributed to enhanced actinorhodin productivity by mediating the pH shock signal to regulators or biosynthesis genes for actinorhodin production.</p

Evaluation Indicators for Priorities of Standardization in Traditional Medicine: using Analytic Hierarchy Process(AHP)

The entire manuscript is available for download as a single PDF file. Higher-resolution images are unavailable. For assistance, please contact [email protected]. Fieldwork Team: Philippe Beaujard (Director of Research, French National Centre for Scientific Research). Technical Team: Dr. Vika Zafrin (Digital Scholarship Librarian, BU Libraries), Eleni Castro (OpenBU and Electronic Theses & Dissertations Librarian, BU Libraries), Dr. Fallou Ngom (Director of the African Studies Center), Dr. Peter Quella (Assistant Director, African Studies Center), Mustapha Hashim Kurfi (PhD Candidate, Department of Political Science), and Zachary Gersten (Research Assistant, African Studies Center). This collection of Malagasy Ajami materials is copied as part of the African Studies Center’s African Ajami Library. This project is partly funded by the BU African Studies Center. We thank Dr. Tim Longman, past Director of the African Studies Center, and the entire African Studies team for their support. For Inquiries: Please contact Professor Fallou Ngom ([email protected]).The material is the fourth part of the second of two texts copied and owned by Jean, a diviner-healer (called ombiasy in Malagasy). Jean belonged to the Anakara Clan and lived in a village called Vatomasina in the Antemoro region (in the valley of the Matatàña River). The original author of the material is unknown. The material was photographed between 1983 and 1990. The material was written on paper school notebooks. While the exact content of material is unknown, it is believed to contain guidance for charms, divination, and healing through prayers, geomancy, and astrology

Effective Management of Single Dominant Follicle with Continuous Administration of Gonadotropin-Releasing Hormone Agonist

With the widespread use of gonadotropin-releasing hormone agonist (GnRH-a) for in vitro fertilization(IVF) program, the cancellation rate during controlled ovarian hyperstimulation(COH} is much lowered. However, poor responders with poor estradioI(E2} rise or single dominant follicle still persist in GnRH-a combined COH, and the decision to cancel the cycle and the counselling of further cycles remain very perplexing. Three poor responders with single dominant follicle during GnRH-a combined COH for IVF were, rather than being cancelled, managed by continuous administration of GnRH-a and restimulation with initial low dosage and subsequent high dosage of follicle-stimulating hormone until an appropriate number of follicles was obtained. While no pregnant case treated in this way, the management resulted in a higher E2 level, and more oocytes and embryos. We suggest that this approach could serve as an alternative to cancellation in GnRH-a combined COH

2D solar wind speeds from 6 to 26 solar radii in solar cycle 24 by using Fourier filtering

Measurement of the solar wind speed near the Sun is important for understanding the acceleration mechanism of the solar wind. In this study, we determine 2D solar wind speeds from 6 to 26 solar radii by applying Fourier motion filters to \textit{SOHO}/LASCO C3 movies observed from 1999 to 2010. Our method successfully reproduces the original flow speeds in the artificially generated data as well as streamer blobs. We measure 2D solar wind speeds from 1-day to 1-year timescales and their variation in solar cycle 24. We find that the solar wind speeds at timescales longer than a month in the solar maximum period are relatively uniform in the azimuthal direction, while they are clearly bimodal in the minimum period, as expected from the \textit{Ulysses} observations and IPS reconstruction. The bimodal structure appears at around 2006, becomes most distinctive in 2009, and abruptly disappears in 2010. The radial evolution of the solar wind speeds resembles the Parker's solar wind solution.Comment: 7 pages, 5 figures; accepted by PR

Efficacy and Safety of a Dexamethasone Implant in Patients with Diabetic Macular Edema at Tertiary Centers in Korea

Purpose. To evaluate the real-world efficacy and safety of the dexamethasone implant (DEX implant) in patients with diabetic macular edema (DME). Methods. Retrospective, multicenter, and noncomparative study of DME patients who were treated with at least one DEX implant. A total of 186 eyes from 165 patients were included. Best-corrected visual acuity (BCVA), central retinal thickness (CRT), complications, and number of retreatments were collected. Data at baseline and monthly for 6 months were analyzed. Results. The average baseline BCVA and CRT were 0.60 LogMAR and 491.6 μm, respectively. The mean BCVA improved until 3 months and then decreased up to 6 months of follow-up (0.53, 0.49, and 0.55 LogMAR at 1, 3, and 6 months; p=0.001, <0.001, and 0.044, resp.). The change of mean CRT was similar to BCVA (345.0, 357.7, and 412.5 μm at 1, 3, and 6 months, p<0.001, <0.001, and <0.001, resp.). 91 eyes (48.9%) received additional treatment with anti-VEGF or DEX implant. The average treatment-free interval was 4.4 months. In group analyses, the DEX implant was more effective in pseudophakic eyes, DME with subretinal fluid (SRF), or diffuse type. Conclusions. Intravitreal dexamethasone implants are an effective treatment for patients with DME, most notably in pseudophakic eyes, DME with SRF, or diffuse type. A half of these patients require additional treatment within 6 months

Nanofluidic Concentration Device for Biomolecules Utilizing Ion Concentration Polarization: Theory, Fabrication, and Applications

This article was published as part of the From microfluidic application to nanofluidic phenomena issueRecently, a new type of electrokinetic concentration devices has been developed in a microfluidic chip format, which allows efficient trapping and concentration of biomolecules by utilizing ion concentration polarization near nanofluidic structures. These devices have drawn much attention not only due to their potential application in biomolecule sensing, but also due to the rich scientific content related to ion concentration polarization, the underlying physical phenomenon for the operation of these electrokinetic concentration devices. This tutorial review provides an introduction to the scientific and engineering advances achieved, in-depth discussion about several interesting applications of these unique concentration devices, and their current limitations and challenges.National Science Foundation (U.S.) (CBET-0347348 & 0854026)National Institutes of Health (U.S.) (Grant EB005743)National Institutes of Health (U.S.) (Grant CA119402)National Institutes of Health (U.S.) (Grant P50-GM68762