15 research outputs found
Acute and subchronic dermal toxicity of nanosilver in guinea pig
Silver has been used as an antimicrobial agent for a long time in different forms, but silver nanoparticles (nanosilver) have recently been recognized as potent antimicrobial agents. Although nanosilver is finding diverse medical applications such as silver-based dressings and silver-coated medical devices, its dermal and systemic toxicity via dermal use has not yet been identified. In this study, we analyzed the potential toxicity of colloidal nanosilver in acute and subchronic guinea pigs. Before toxicity assessments, the size of colloidal nanosilver was recorded in sizes <100 nm by X-ray diffraction and transmission electron microscopy. For toxicological assessments, male guinea pigs weighing 350 to 400 g were exposed to two different concentrations of nanosilver (1000 and 10,000 μg/mL) in an acute study and three concentrations of nanosilver (100, 1000, and 10,000 μg/mL) in a subchronic study. Toxic responses were assessed by clinical and histopathologic parameters. In all experimental animals the sites of exposure were scored for any type of dermal toxicity and compared with negative control and positive control groups. In autopsy studies during the acute test, no significant changes in organ weight or major macroscopic changes were detected, but dose-dependent histopathologic abnormalities were seen in skin, liver, and spleen of all test groups. In addition, experimental animals subjected to subchronic tests showed greater tissue abnormalities than the subjects of acute tests. It seems that colloidal nanosilver has the potential to provide target organ toxicities in a dose- and time-dependent manner
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How does organizational learning contribute to corporate social responsibility and innovation performance? The dynamic capability view
Purpose: Innovative organizations are increasingly facing challenges in a dynamic market to address corporate social responsibility (CSR) issues; however, research on how organizational learning (OL) contributes to organizations’ social responsibility and innovation remains sparse. This study aims to bridge the gap in previous research and examines how OL and dynamic capabilities (DCs) act as drivers of CSR performance (CSRP) and innovation performance.
Design/methodology/approach: This study is survey-based and uses time-lagged, multisource data from 151 pharmaceutical industry-related companies in Iran. Structural equation modeling was applied to test the validity of the measurement model and hierarchical regression was used to test the key hypotheses.
Findings: DCs mediate the relationship between OL and CSRP. Moreover, CSRP significantly mediates the relationship between OL and innovation.
Originality/value: Drawing on the perspective of DCs, this research is among the first to offer new insights in a new context on what antecedent conditions lead to the successful implementation of organizational CSRP and how CSRP would, in turn, lead to subsequent innovation performance improvement
Biophysical, docking, and cellular studies on the effects of cerium oxide nanoparticles on blood components: in vitro
Neda Eskandari,1,* Mohammad Mahdi Nejadi Babadaei,1,* Sanaz Nikpur,2 Ghazal Ghasrahmad,2 Farnoosh Attar,3 Masoumeh Heshmati,1 Keivan Akhtari,4 Seyed Mahdi Rezayat Sorkhabadi,5 Seyyedeh Elaheh Mousavi,5 Mojtaba Falahati6 1Department of Cellular and Molecular Biology, Faculty of Advance Science and Technology, Pharmaceutical Sciences Branch, Islamic Azad University (IAUPS), Tehran, Iran; 2Department of Toxicology and Pharmacology, Faculty of Pharmacy, Pharmaceutical Science Branch, Islamic Azad University (IAUPS), Tehran, Iran; 3Department of Biology, Faculty of Food Industry & Agriculture, Standard Research Institute (SRI), Karaj, Iran; 4Department of Physics, University of Kurdistan, Sanandaj, Iran; 5Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; 6Department of Nanotechnology, Faculty of Advance Science and Technology, Pharmaceutical Sciences Branch, Islamic Azad University (IAUPS), Tehran, Iran *These authors contributed equally to this work Introduction: The application of nanoparticles (NPs) in medicine and biology has received great interest due to their novel features. However, their adverse effects on the biological system are not well understood. Materials and methods: This study aims to evaluate the effect of cerium oxide nanoparticles (CNPs) on conformational changes of human hemoglobin (HHb) and lymphocytes by different spectroscopic (intrinsic and synchronous fluorescence spectroscopy and far and near circular dichroism [CD] spectroscopy), docking and cellular (MTT and flow cytometry) investigations.Results and discussion: Transmission electron microscopy (TEM) showed that CNP diameter is ~30 nm. The infrared spectrum demonstrated a strong band around 783 cm−1 corresponding to the CNP stretching bond. Fluorescence data revealed that the CNP is able to quench the intrinsic fluorescence of HHb through both dynamic and static quenching mechanisms. The binding constant (Kb), number of binding sites (n), and thermodynamic parameters over three different temperatures indicated that hydrophobic interactions might play a considerable role in the interaction of CNPs with HHb. Synchronous fluorescence spectroscopy indicated that microenvironmental changes around Trp and Tyr residues remain almost unchanged. CD studies displayed that the regular secondary structure of HHb had no significant changes; however, the quaternary structure of protein is subjected to marginal structural changes. Docking studies showed the larger CNP cluster is more oriented toward experimental data, compared with smaller counterparts. Cellular assays revealed that CNP, at high concentrations (>50 µg/mL), initiated an antiproliferative response through apoptosis induction on lymphocytes. Conclusion: The findings may exhibit that, although CNPs did not significantly perturb the native conformation of HHb, they can stimulate some cellular adverse effects at high concentrations that may limit the medicinal and biological application of CNPs. In other words, CNP application in biological systems should be done at low concentrations. Keywords: cerium oxide nanoparticles, human hemoglobin, fluorescence spectroscopy, thermodynamic, circular dichroism spectroscopy, docking, flow cytometr
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10.1080/00207540410001671615International Journal of Production Research42163301-3331IJPR