Results 1 - 10 of 3867
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[en] When considering the safety of ingested nanomaterials, it is important to quantitate their transfer across intestinal cells; however, little information exists about the effects of nanomaterial size or exposure side (apical versus basolateral epithelial surface) on nanomaterial transfer. Here, we examined cellular internalization and transcellular transport, and the effects of nanomaterials on Caco-2 monolayers after apical or basolateral exposure to Ag or Au nanoparticles with various sizes. After apical treatment, both internalization and transfer to the basolateral side of the monolayers were greater for smaller Ag nanoparticles than for larger Ag nanoparticles. In contrast, after basolateral treatment, larger Ag nanoparticles were more internalized than smaller Ag nanoparticles, but the transfer to the apical side was greater for smaller Ag nanoparticles. Au nanoparticles showed different rules of internalization and transcellular transport compared with Ag nanoparticles. Furthermore, the paracellular permeability of the Caco-2 monolayers was temporarily increased by Ag nanoparticles (5 μg/mL; diameters, ≤10 nm) following basolateral but not apical exposure. We conclude that the internalization, transfer, and effects of nanomaterials in epithelial cell monolayers depend on the size and composition of nanomaterials, and the exposure side. - Highlights: • Ag and Au nanoparticles can transfer across Caco-2 monolayers. • Cellular uptake of nanoparticles change between apical and basolateral exposure. • Basolateral Ag nanoparticle exposure increases the permeability of Caco-2 monolayers.
[en] Modern day microprocessor has increased remarkably in computational capacity which in turn has resulted in generation of higher heat fluxes. Air based conventional heat extraction systems are bungling to eradicate the aforesaid heat fluxes as the need of information technology and high computational facility is skyrocketing. In this present study, numerical simulation is carried out to analyze and compare the thermal performance of a heat pipe combined with forced convection heat transfer mechanism utilizing nanofluids in a mini channel heat sink for application in CPU cooling. Two phase heat transfer phenomenon employed in heat pipe can accomplish extreme heat removal rate. Temperature gradient along with thermal resistance between the coolant and mini channel heated wall is significantly reduced due to the application of nanofluids. Convective heat transfer coefficient at the condenser end of the heat pipe is noticeably improved with application of nanoparticles into distilled water. (author)
[en] The aim of this paper is to discuss the possibility of theoretically engineering multifunctional nanomaterials. The calculations were performed for 1D and 2D nanomaterials by using results obtained within the Hubbard model (HM). The main results of the HM are briefly reviewed. The conclusion is that the approach taken in this paper is a distinct improvement over those in the literature.In the present paper results of applications of the HM are directly used in examples of engineering nanomaterials. On the other hand, in the literature calculations were performed by ab initio methods and then fitted to the form of the Hamiltonian of the HM. (paper)
[en] NM's potential to induce adverse effects in humans or the environment is being addressed in numerous research projects, and methods and tools for NM hazard identification and risk assessment are advancing. This article describes how integrated approaches for the testing and assessment of NMs can ensure the safety of nanomaterials, while adhering to the 3Rs principle. - Highlights: • Testing each NM in all of its modifications will cause an insurmountable amount of testing. • Integrated approaches for testing and grouping of NM are needed. • Such approaches should take the source-to-adverse-outcome pathways into consideration. • A tiered approach addressing actual concerns with specific NM is proposed.
[en] Silver nanomaterials (AgNMs) ubiquitously known for their biological applications are studied here in terms of their shape-dependent antibacterial and anti-biofilm effect. Chemically synthesized nano-cubes (AgNCs) with size range around 150-200 nm were compared for their biological activity with commercial nano-sphere (AgNS) of comparable size (~160 nm). The antibacterial activity against both Escherichia coli and Staphylococcus aureus showed higher activity for nano-cubes compared with nano-spheres.The synergistic role of AgNMs with antibiotic ampicillin was also found promising. A four times enhancement and an increase of nearly 25% of antibiotic activity at 0.0625 mg ml-1 concentration was found with 0.05 mg ml-1 of AgNCs in agar and broth media, respectively. Anti-biofilm effect towards E. coli and S. aureus was also evaluated. AgNCs showed equal importance in biofilm disruption with 20% inhibition activity, which was yet again found better in-comparison with AgNSs. The study shows that AgNCs with distinct faces and edges could show efficient anti-bacterial effect and so such intelligently designed material could pave path for imminent medical challenges. (author)
[en] Incorporation of fulvic acid (FA) into the framework of hydroxyapatite particle to synthesis NHAP functionalized with FA (NHAP-FA) as a new smart nanocomposite is achieved. Some analytical methods such as EDX, FTIR, XRD, and TEM defined it. Preliminary study on the possible radiolabeling of NHAP-FA with 141,143Ce, 152,154Eu, 159,161Gd as represented radio-lanthanides that are gaining more attention in the last decades is carried out. The obtained results were revealed that a significant sorption affinity of radio-lanthanides (∼98%). Application on the environmental remediation towards the removal of some radionuclides (152,154Eu, 60Co, 99Mo, 63Ni and 137Cs) has been evaluated. (author)
[en] Indonesia is the sixth largest corn producer in the world. The high corn production in Indonesia is correlated with waste corn cob produced. However, corn cob waste is not fully utilized, mainly only disposed and burned that caused environmental pollution. One alternative to utilize of corn cob is to be processed to cellulose based superabsorbent polymer (SAP) hydrogel. In this study, cellulose based hydrogel was prepared using epichlorohydrin (Ech) as cross-linking agent and modified particle size to produce nanohydrogel. The aim of the research was to find out the effect of Ech concentration and cellulose: solvent ratio on the characteristic of nanohydrogel. The treatment tested was Ech concentration of 4%, 16% and 28%; whereas the ratio of cellulose: solvent was 1: 2 (A2) and 1: 4 (A4). Parameters observed were swelling ratio, gel fraction, texture and morphology of the resulted hydrogel. Result showed that the higher the Ech concentration the swelling ratio increasing. The best treatments were nanohydrogel with Ech concentration 28% and cellulose: solvent ratio 1: 2 with characteristics as follows: 514% swelling ratio, 44% gel fraction and 0.33 mJ hardness, with morphology showed higher porosity. This hydrogel has a wide potential as water absorbent material in dry agricultural areas and can be used as fertilizer carrier agent. (paper)
[en] A quantitative model for the size-dependent Young’s modulus Y(D) of nanomaterials is established in this work by considering the modulus of single bond and bond number in nanomaterials. Due to bond relaxation, the single bond strength and it’s elastic modulus are enhanced as size drops, while bond number is decreased. This makes the Young’s moduli of nanomaterials possess different change with size. If compared with bulk Young’s modulus Y0, both the stiffer with Y(D) > Y0 and the softer with Y(D) < Y0 for different nanomaterials are predicted. The corresponding experimental or simulation results show their good consistence with the model predictions, which greatly confirms the reasonability of the established model. (paper)
[en] With the evolution of the field of nanomaterials in the past number of years, it has become apparent that it will be key to future technological developments. However, while there are unlimited research undertakings on nanomaterials, limited research results on nanomaterial costs exist; all in spite of the generous funding that nanotechnology projects have received. There has recently been an exponential increase in the number of studies concerning health-related nanomaterials, considering the various medical applications of nanomaterials that drive medical innovation. This work aims to analyze the effect of the cost factor on acceptability of health-related nanomaterials independently or in relation to material toxicity. It appears that, from the materials studied, those used for cancer treatment applications are more expensive than the ones for drug delivery. The ability to evaluate cost implications improves the ability to undertake research mapping and develop opinions on nanomaterials that can drive innovation.