Articles de revues : « Nanoparticella »

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Marengo, Enrico, Norberto Roveri et Dario Marengo. « Particelle nanostrutturate di idrossiapatite biomimetica come sistema di delivery di micro e macro elementi nelle colture biologiche ». BIO Web of Conferences 56 (2023) : 01003. http://dx.doi.org/10.1051/bioconf/20235601003.

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Nanoparticelle biomimetiche di idrossiapatite drogate con ioni metallici (Cu, Fe, Mg, Zn, K) sono state utilizzate in formulazioni contenenti basse concentrazioni di rame (Cu) e zolfo (S) per controllare la peronospora (plasmopara viticola) e l'oidio (erysiphe necator) della vite. I formulati sono stati testati in campo sulla varietà di vino "Dolcetto" coltivata secondo tecniche di agricoltura biologica, e la loro efficacia è stata confrontata con prodotti commerciali contenenti miscela bordolese e zolfo. I dati indicano che le formulazioni contenenti bassi dosaggi di rame e zolfo possono essere trasportati in modo efficiente dalle nanoparticelle di idrossiapatite biomimetica e possono ridurre la presenza di micota sulle foglie della vite. Nessun residuo di rame e zolfo è stato rilevato in campioni di vino ottenuti da viti in cui è stata utilizzata l'idrossiapatite biomimetica. Il drogaggio di nanoparticelle di idrossiapatite biomimetica con metalli di transizione è un modo efficiente per fornire micro e macro-elementi alle piante a basso livello di dosaggio. Le formulazioni contenenti idrossiapatite funzionano anche come supporti a lento rilascio di macronutrienti come elementi di calcio e fosforo.

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Trzaskus, K. W., A. J. B. Kemperman et D. C. Nijmeijer. « Fouling Behavior of Silver Nanoparticels During Membrane Filtration ». Procedia Engineering 44 (2012) : 2096–97. http://dx.doi.org/10.1016/j.proeng.2012.09.058.

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Kilic, Mehmet Emin, et Sakir Erkoc. « Structural Properties of ZnO Nanoparticels and Nanorings : Molecular Dynamics Simulations ». Journal of Computational and Theoretical Nanoscience 10, n^o 6 (1 juin 2013) : 1490–96. http://dx.doi.org/10.1166/jctn.2013.2878.

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Wang, X., Z. Yang, Y. Zhang, L. Jing, Y. Zhao, Y. Yan et K. Sun. « MnO2Supported Pt Nanoparticels with High Electrocatalytic Activity for Oxygen Reduction Reaction ». Fuel Cells 14, n^o 1 (10 décembre 2013) : n/a. http://dx.doi.org/10.1002/fuce.201300102.

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Haroun, Ahmed A., Abdel-Tawab H. Mossa et Samia M. M. Mohafrash. « Preparation and Biochemical Evaluation of Functionalized Multi-Walled Carbon Nanotubes with Punica granatum Extract ». Current Bioactive Compounds 15, n^o 1 (6 février 2019) : 138–44. http://dx.doi.org/10.2174/1573407214666180530095912.

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Background: Funcionalized multi-walled carbon nanotubes (ox-MWCNTs) were used for the preparation of therapeutic nanoparticles for delivery of some bioactive compounds. Consequently, this work deals with the preparation of grafted MWCNTs with n-vinyl caprolactam in the presence of pomegranate peel extract (P. granatum), titanium dioxide (TiO2) and/or silver nanoparticeles and their toxic effects on male mice using in vivo biological examination (liver and kidney dysfunction biomarkers) and the histopathological analysis. Methods: P. granatum extract was immobilized onto functionalized MWCNTs using simple adsorption technique. Moreover, The prepared materials were analyzed by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM). In vivo examination using liver and kidney dysfunction biomarkers was investigated. In addition, the histopathological study was carried out. Results: The ox-MWCNTs induced significant elevation in the liver enzymes including AST, ALT and ALP relative to the control group. While, the treatment with P. granatum extract only did not induce any change in the liver and kidney biomarkers. In other words, P. granatum extract loaded onto functionalized MWCNTs showed low effects on liver enzymes and kidney function biomarkers in the treated mice in comparison with ox-MWCNTs and extract separately. Moreover, histopathological analysis revealed that the P. granatum extract functionalized MWCNTs exhibited normal renal tissue with no histopathological alteration. Conclusion: The grafted MWCNTs with n-vinyl caprolactam in the presence of pomegranate peel extract (P. granatum), titanium dioxide (TiO2) and/or silver nanoparticeles were successfully prepared. SEM-micrographs showed complete coating of MWCNTs fiber with the extract. The prepared materials resulted in no toxic effects and the histopathological findings were confirmed by inflammation of the liver and kidney tissues.

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Zamorina, S. A., P. V. Khramtsov, M. B. Rayev, V. P. Timganova, M. S. Bochkova, A. I. Nechaev, E. O. Shunkin, O. G. Khaziakhmatova, V. V. Malaschenko et L. S. Litvinova. « Graphene Oxide Nanoparticels Interaction with Jurkat Cell Line in Cell-IQ System ». Doklady Biochemistry and Biophysics 501, n^o 1 (novembre 2021) : 438–43. http://dx.doi.org/10.1134/s1607672921060089.

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Ruan, Li Li, Da Xin Wang, You Wei Zhang, Jiong Xin Zhao, Min Wu Wang, Xiu Fang Zhang et Nan Liang Chen. « Study on Preparation and Property of Drug Loading of AZM-PCL Nanoparticels ». Applied Mechanics and Materials 121-126 (octobre 2011) : 1764–68. http://dx.doi.org/10.4028/www.scientific.net/amm.121-126.1764.

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This study was to prepare polycaprolactone (PCL) nanoparticles. The biodegradable PCL was used as the carrier, and Azithromycin (AZM) was used as the model drug. AZM-PCL nanoparticles (AZM-PCL-NPS) were prepared by desolvation method. The effect of preparation condition: concentration of PCL, molecular weight of PCL, organic solvents, dosage ratio and so on, were specially noted and compared. A homogeneous size distribution and good dispersion were observed, the average diameter was around 70~400 nm, and the distribution index was 0.036~0.136. The drug loading reached 27.69 %, and the efficiency of encapsulation reached as high as 93.25%. The results were better than the other similar researches, this preparation way was successful.

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Yang, Chun, Feng Yan Ge, Jin Cai Li, Zai Sheng Cai et Fang Fang Qin. « Silver Nanoparticles with Enhanced Fluorescence Effects on Fluorescein Derivative ». Advanced Materials Research 602-604 (décembre 2012) : 187–91. http://dx.doi.org/10.4028/www.scientific.net/amr.602-604.187.

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Silver nanoparticles were prepared by sodium borohydride reduction method for analyzing metal-enhanced fluorescence property. Some variables including the dosage of reagent, reacting temperature and pH value had been investigated. Subsequently, a comparison of metal-enhanced fluorescence efficiency was made between two kinds of fluorescent dyes, namely fluorescein and 6-carboxyfluorescein at different silver concentrations. The experimental results show that the fluorescence of both dyes are remarkably enhanced. It is interesting to note that the increase of emission intensity is stronger than that of their corresponding excitation ones. Furthermore, a 5.038-fold increase in fluorescence for 6-carboxyfluorescein while a 2.506-fold increase for fluorescein are observed. This may attribute to the interaction between dyes and silver nanoparticels.

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ZHANG Yang, 张杨, 李学红 LI Xue-hong et 彭成晓 PENG Cheng-xiao. « Tunable Photoluminescence of ZnO Films with Different Surfaces by The Coating of Au Nanoparticels ». Chinese Journal of Luminescence 33, n^o 12 (2012) : 1299–303. http://dx.doi.org/10.3788/fgxb20123312.1299.

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Xuan, Liang, Li-Jiao Tian, Tian Tian, Xue-Meng Wang, Dian-Hai Yang et Han-Qing Yu. « In situ synthesizing silver nanoparticels by bio-derived gallic acid to enhance antimicrobial performance of PVDF membrane ». Separation and Purification Technology 251 (novembre 2020) : 117381. http://dx.doi.org/10.1016/j.seppur.2020.117381.

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Shagdarova, Balzhima, Mariya Konovalova, Yuliya Zhuikova, Alexey Lunkov, Vsevolod Zhuikov, Dolgor Khaydapova, Alla Il’ina, Elena Svirshchevskaya et Valery Varlamov. « Collagen/Chitosan Gels Cross-Linked with Genipin for Wound Healing in Mice with Induced Diabetes ». Materials 15, n^o 1 (21 décembre 2021) : 15. http://dx.doi.org/10.3390/ma15010015.

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Diabetes mellitus continues to be one of the most common diseases often associated with diabetic ulcers. Chitosan is an attractive biopolymer for wound healing due to its biodegradability, biocompatibility, mucoadhesiveness, low toxicity, and hemostatic effect. A panel of hydrogels based on chitosan, collagen, and silver nanoparticels were produced to treat diabetic wounds. The antibacterial activity, cytotoxicity, swelling, rheological properties, and longitudinal sections of hydrogels were studied. The ability of the gels for wound healing was studied in CD1 mice with alloxan-induced diabetes. Application of the gels resulted in an increase in VEGF, TGF-b1, IL-1b, and TIMP1 gene expression and earlier wound closure in a comparison with control untreated wounds. All gels increased collagen deposition, hair follicle repair, and sebaceous glands formation. The results of these tests show that the obtained hydrogels have good mechanical properties and biological activity and have potential applications in the field of wound healing. However, clinical studies are required to compare the efficacy of the gels as animal models do not reproduce full diabetes pathology.

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Dalmar Chaka. « Utilizzo della nanotecnologia Nello sviluppo di fertilizzanti organici e pesticide ». International Journal of Science and Society 4, n^o 2 (12 juillet 2022) : 355–64. http://dx.doi.org/10.54783/ijsoc.v4i2.479.

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Non si può negare che lo sviluppo della tecnologia e il suo utilizzo sia strettamente correlato all'aumento della competitività dell'industria di un paese. È necessaria una maggiore conoscenza e padronanza delle nuove tecnologie per vincere la concorrenza nell'era del commercio globale sia da parte del governo che dell'industria. Un esempio di tecnologia che viene discussa caldamente è la nanotecnologia. L'uso della nanotecnologia è ben noto, anche nei settori della salute, della cosmesi e dell'agricoltura. Fondamentalmente, il principio della scoperta delle nanotecnologie è massimizzare la resa o la produzione delle colture riducendo al minimo l'uso di fertilizzanti, pesticidi e altri bisogni monitorando le condizioni del suolo come le radici e applicandole direttamente al bersaglio in modo che nulla venga sprecato. Per i pesticidi, se applicato, sarà in grado di ridurre al minimo l'uso di pesticidi sulle piante perché solo gli insetti bersaglio sono interessati. L'uso della nanotecnologia nei fertilizzanti consentirà il rilascio dei nutrienti contenuti nel fertilizzante può essere controllato. Quindi vengono rilasciati solo i nutrienti che verranno effettivamente assorbiti dalle piante, in modo che non ci sia perdita di nutrienti ci siano bersagli indesiderati come suolo, acqua e microrganismi. Nei nano fertilizzanti, i nutrienti possono essere sotto forma di incapsulamento di nanomateriali, ricoperti da un sottile strato protettivo o rilasciati sotto forma di emulsione da nanoparticelle.

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Xu, Jicheng, Min Zhang, Ping Cao, Benu Adhikari et Chaohui Yang. « Microorganisms control and quality improvement of stewed pork with carrots using ZnO nanoparticels combined with radio frequency pasteurization ». Food Bioscience 32 (décembre 2019) : 100487. http://dx.doi.org/10.1016/j.fbio.2019.100487.

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Elahi, S. M., A. Taghizadeh, A. Hadizadeh et L. Dejam. « Effect of Thickness and Annealing on Structural and Optical Properties of Bi2Te3 Thin Films Prepared from Bi2Te3 Nanoparticels ». International Journal of Thin Films Science and Technology 3, n^o 1 (1 janvier 2014) : 13–18. http://dx.doi.org/10.12785/ijtfst/030103.

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Shan, Feng, et Tong Zhang. « Shape and Size Dependent Light Absorption Enhancement of Silver Nanostructures in Organic Solar Cells ». Solid State Phenomena 266 (octobre 2017) : 90–94. http://dx.doi.org/10.4028/www.scientific.net/ssp.266.90.

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Metal nanoparticles (MNPs) induced light absorption enhancement using for the improvement of power conversion efficiency of organic solar cells (OSCs) is a new research direction in photovoltaics. However, the device performance influence of the shape and size of MNPs has not been well investigated. In this paper, we focused on the comparison study of the optical absorption enhancement between silver nanospheres (Ag-NSs) and silver nanocubes (Ag-NCs) which are embedded in the active layer of OSCs using finite element method (FEM) simulation. Influence of the structural parameters, including the size and shape of nanoparticels, and their relative distance are systematically discussed. The results indicated that the light absorption enhancement employing Ag-NCs is much higher than that of Ag-NSs in the 300–800 nm wavelength range. Meantime, once the distance between the adjacent nanoparticles is well controlled, the optimal absorption enhancement factor of OSCs can be obtained. As the scattering cross-section of Ag-NCs is much higher than that of Ag-NSs over a broad wavelength range, the optimized light enhancement of Ag-NCs reaches 19 % which is 1.26 times higher than that of Ag-NSs.

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Ralli, M., R. Rolesi, R. Anzivino, R. Turchetta et A. R. Fetoni. « Acquired sensorineural hearing loss in children : current research and therapeutic perspectives ». Acta Otorhinolaryngologica Italica 37, n^o 6 (décembre 2017) : 500–508. http://dx.doi.org/10.14639/0392-100x-1574.

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La conoscenza dei meccanismi fisiopatologici delle condizioni responsabili dellipoacusia acquisita nei bambini, tra cui le infezioni virali e batteriche, lesposizione al rumore, lototossicità da chemioterapici ed antibiotici aminoglicosidici, è in costante aumento e sta portando ad un progressivo cambiamento della gestione diagnostica e clinica del bambino ipoacusico. Le infezioni virali rappresentano la causa più frequente di sordità infantile acquisita, seguita dalla tossicità di antibiotici e chemioterapici; mentre lesposizione al rumore, soprattutto negli adolescenti, rappresenta un fattore emergente. Le terapie farmacologiche protettive attualmente in uso includono steroidi, antiossidanti, antivirali; lefficacia degli antiossidanti è ancora in fase di conferma clinica anche se vi sono significative evidenze sperimentali, mentre i farmaci steroidei ed antivirali sono certamente validi seppur la loro tossicità sistemica rappresenti ancora un problema non chiarito per i quali la somministrazione locale potrebbe rappresentare una possibile evoluzione. Le prospettive di ricerca future includono luso di nanoparticelle per veicolare molecole direttamente nel sito di danno; inoltre, la terapia genica con linserimento di materiale genetico allinterno delle cellule per la cura di condizioni da alterazione del patrimonio genetico con la produzione di proteine normali, potrebbe svolgere un ruolo rilevante nella cura e soprattutto nella prevenzione delle sordità acquisite; infine, la terapia rigenerativa e limpianto delle cellule staminali, nonostante il loro ruolo nellorecchio interno sia ancora dibattuto, per le notevole limitazioni del loro impiego, potrebbe trovare un ruolo nei processi riparativi più che nella differenziazione in cellule sensoriali.

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M. Tóth, Orsolya, Ákos Menyhárt, Rita Frank, Dóra Hantosi, Eszter Farkas et Ferenc Bari. « Tissue Acidosis Associated with Ischemic Stroke to Guide Neuroprotective Drug Delivery ». Biology 9, n^o 12 (11 décembre 2020) : 460. http://dx.doi.org/10.3390/biology9120460.

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Ischemic stroke is a leading cause of death and disability worldwide. Yet, the effective therapy of focal cerebral ischemia has been an unresolved challenge. We propose here that ischemic tissue acidosis, a sensitive metabolic indicator of injury progression in cerebral ischemia, can be harnessed for the targeted delivery of neuroprotective agents. Ischemic tissue acidosis, which represents the accumulation of lactic acid in malperfused brain tissue is significantly exacerbated by the recurrence of spreading depolarizations. Deepening acidosis itself activates specific ion channels to cause neurotoxic cellular Ca2+ accumulation and cytotoxic edema. These processes are thought to contribute to the loss of the ischemic penumbra. The unique metabolic status of the ischemic penumbra has been exploited to identify the penumbra zone with imaging tools. Importantly, acidosis in the ischemic penumbra may also be used to guide therapeutic intervention. Agents with neuroprotective promise are suggested here to be delivered selectively to the ischemic penumbra with pH-responsive smart nanosystems. The administered nanoparticels release their cargo in acidic tissue environment, which reliably delineates sites at risk of injury. Therefore, tissue pH-targeted drug delivery is expected to enrich sites of ongoing injury with the therapeutical agent, without the risk of unfavorable off-target effects.

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Zhao, Jiling, Chen Wang, Shixing Wang, Libo Zhang et Bing Zhang. « Selective recovery of Au(III) from wastewater by a recyclable magnetic Ni0.6Fe2.4O4 nanoparticels with mercaptothiadiazole : Interaction models and adsorption mechanisms ». Journal of Cleaner Production 236 (novembre 2019) : 117605. http://dx.doi.org/10.1016/j.jclepro.2019.117605.

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A. A. Aljabali, Alaa, Hamid A. Bakshi, Faruck L. Hakkim, Yusuf A. Haggag, Khalid M. Al-Batanyeh, Mazhar S. Al Zoubi, Bahaa Al-Trad et al. « Albumin Nano-Encapsulation of Piceatannol Enhances Its Anticancer Potential in Colon Cancer Via Downregulation of Nuclear p65 and HIF-1α ». Cancers 12, n^o 1 (1 janvier 2020) : 113. http://dx.doi.org/10.3390/cancers12010113.

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Piceatannol (PIC) is known to have anticancer activity, which has been attributed to its ability to block the proliferation of cancer cells via suppression of the NF-kB signaling pathway. However, its effect on hypoxia-inducible factor (HIF) is not well known in cancer. In this study, PIC was loaded into bovine serum albumin (BSA) by desolvation method as PIC–BSA nanoparticles (NPs). These PIC–BSA nanoparticles were assessed for in vitro cytotoxicity, migration, invasion, and colony formation studies and levels of p65 and HIF-1α. Our results indicate that PIC–BSA NPs were more effective in downregulating the expression of nuclear p65 and HIF-1α in colon cancer cells as compared to free PIC. We also observed a significant reduction in inflammation induced by chemical colitis in mice by PIC–BSA NPs. Furthermore, a significant reduction in tumor size and number of colon tumors was also observed in the murine model of colitis-associated colorectal cancer, when treated with PIC–BSA NPs as compared to free PIC. The overall results indicate that PIC, when formulated as PIC–BSA NPs, enhances its therapeutic potential. Our work could prompt further research in using natural anticancer agents as nanoparticels with possible human clinical trails. This could lead to the development of a new line of safe and effective therapeutics for cancer patients.

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Droigk, Christine, Marco Maass et Alfred Mertins. « Direct multi-dimensional Chebyshev polynomial based reconstruction for magnetic particle imaging ». Physics in Medicine & ; Biology 67, n^o 4 (16 février 2022) : 045014. http://dx.doi.org/10.1088/1361-6560/ac4c2e.

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Abstract Magnetic Particle Imaging is a tomographic imaging technique that measures the voltage induced due to magnetization changes of magnetic nanoparticle distributions. The relationship between the received signal and the distribution of the nanoparticels is described by the system function. A common method for image reconstruction is using a measured system function to create a system matrix and set up a regularized linear system of equations. Since the measurement of the system matrix is time-consuming, different methods for acceleration have been proposed. These include modeling the system matrix or using a direct reconstruction method in time, known as X-space reconstruction. In this work, based on the simplified Langevin model of paramagnetism and certain approximations, a direct reconstruction technique for Magnetic Particle Imaging in the frequency domain with two- and three-dimensional Lissajous trajectory excitation is presented. The approach uses Chebyshev polynomials of second kind. During reconstruction, they are weighted with the frequency components of the voltage signal and additional factors and then summed up. To obtain the final nanoparticle distribution, this result is rescaled and deconvolved. It is shown that the approach works for both simulated data and real measurements. The obtained image quality is comparable to a modeled system matrix approach using the same simplified physical assumptions and no relaxation effects. The reconstruction of a 31 × 31 × 31 volume takes less than a second and is up to 25 times faster than the state-of-the-art Kaczmarz reconstruction. Besides, the derivation of the proposed method shows some new theoretical aspects of the system function and its well-known observed similarity to tensor products of Chebyshev polynomials of second kind.

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Li, Zhuoxin, Lingyi Zhou, Yuyan Qin, Xin Sun, Qianzhe Li, Mengyu Yang, Beibei Yu, Fengyi Du et Miaomiao Zhang. « Mangasese doped polypyrole nanoparticels for photothermal/chemodynamic therapy and immune activation ». Nanotechnology, 4 octobre 2022. http://dx.doi.org/10.1088/1361-6528/ac9739.

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Abstract Photothermal therapy (PTT) is a promising treatment that efficiently suppresses local cancer, but fails to induce a robust antitumor immune response against tumor metastasis and recurrence. In this study, a NIR responsive nano-immunostimulant (Mn/A-HP NI) is fabricated by entrapping manganese and azo-initiator (AIPH) into hyaluronic acid-based polypyrrole nanoparticle. The as-prepared Mn/A-HP NIs with a high photothermal conversion efficiencey of 20.17% dramatically induced the imunogenic cell death (ICD) of tumor cells and triggered the release ATP and HMGB1. Meanwhile, the hyperthermia induced AIPH decomposition to produce alkyl radicals which further destroyed cancer cells. Furthermore, the Mn/A-HP NIs were capable of promoting the maturation and antigen cross-presentation ability of dendritic cells (DCs). Consequently, the multifunctional Mn/A-HP NIs provided a combined treatment via integrating PTT/chemo-dynamic therapy (CDT) and immune activation for tumor therapy.

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Simeonova, Katya, et Ganka Milanova. « Applications of nanoparticels in molecular and cellular biology and cancer research ». BMC Proceedings 5, S8 (22 novembre 2011). http://dx.doi.org/10.1186/1753-6561-5-s8-p58.

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« Aumento della biodisponibilità dell’insulina, somministrata per via orale, grazie a nuove nanoparticelle LDH-DCA-HA ». il Diabete 34, n^o 1 (12 mai 2022). http://dx.doi.org/10.30682/ildia2201e.

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Sindhu, S., et BJ Gireesha. « Irreversibility analysis of nanofluid flow in a vertical microchannel with the influence of particle shape ». Proceedings of the Institution of Mechanical Engineers, Part E : Journal of Process Mechanical Engineering, 21 septembre 2020, 095440892095811. http://dx.doi.org/10.1177/0954408920958110.

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Augmentation of thermal performance in heat transfer system has become research hotspot nowadays. Numerous techniques are carried out to pick up the effective heat transport mechanism for designing high efficient thermal frameworks which has extensive practical uses in industrial process. In the current study, mixture model has been implemented for better describing the characteristics of nanoparticles in a vertical microchannel. The nondimensional equations are computed by using Runge Kutta Fehlberg method. Effect of heat source, buoyancy force and convective boundary on the thermal system has been demonstrated. The role of spheroidal nanoparticles on thermal conductivity of the conventional fluid has been examined. The causes of irreversibilities in a microchannel due to nanoliquid flow has been reported in the current research work. It is obtained that Aluminum foam has higher thermal field compared to Al2 O3. Entropy generation is reduced by lowering Eckert number and Grashof number. It is explored that nanofluid containing oblate shaped nanoparticels has higher thermal conductivity ratio.

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Spagnolo, Antonio G., et Viviana Daloiso. « Oltre il visibile Le nanotecnologie e la nanomedicina : definizioni e problematiche bioetiche ». Medicina e Morale 57, n^o 3 (30 juin 2008). http://dx.doi.org/10.4081/mem.2008.280.

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Il presente articolo intende inquadrare e definire le implicazioni etiche riguardanti l’applicazione biomedica delle nanotecnologie, attraverso la valutazione dello stato dell’arte. Le nanotecnologie, espressione dell’abilità umana di manipolare la materia su scala atomico/molecolare, si presentano come uno strumento in grado di modificare la ricerca scientifica e la medicina in maniera radicale. Dibattiti ad ogni livello hanno sottolineato la difficoltà di darne una definizione chiara ed univoca, a causa della convergenza di più ambiti del sapere in esse coinvolti. Nonostante le nanotecnologie siano già presenti nelle scienze computeristiche e nell’elettronica, è in ambito medico-sanitario che si prospettano le applicazioni più entusiasmanti: strumenti di diagnosi e somministrazione di farmaci meno invasivi e più efficaci. Queste tecnologie si presentano infatti allo stesso tempo come terapie ma anche come strumenti di prevenzione unici. Le stesse caratteristiche che rendono singolare l’impiego delle nanotecnologie in medicina, suggeriscono altresì precauzioni: da una parte infatti la di mensione piccolissima (atomico-molecolare) delle nanoparticelle facilita il loro ingresso nell’organismo umano, oltrepassando le difese naturali dell’organismo, agevolando una distribuzione dei farmaci altamente mirata. Dall’altra parte queste stesse caratteristiche posso rivelarsi dannose per l’organismo umano (interazione tra nanoparticelle e sistema biologico umano, elevato rapporto tra massa e superficie, mobilità). Poiché si tratta di tecnologie in rapida progressione i cui sviluppi non sono facili da predire, i rischi, anche solo quelli potenziali, devono essere accuratamente valutati sia per le applicazioni presenti sia per quelle future. Pertanto inquadrare le implicazioni bioetiche delle nanotecnologie significa comprendere e valutare il loro impatto sulla salute umana. ---------- The aim of this contribution is to outline and define some ethical implications concerning biomedical applications of nanotechnologies. Nanotechnology, expression of the human ability to manipulate matter on a molecular and atomic scale, provide an instrument able to change scientific research and medicine in a radical way. Debate at all levels have pointed out the common difficulty to give a clear and univocal definition of nanotechnologies, due to the convergence of technologies there involved. Although these technologies have already been implemented in electronics or computer science, the most useful ones are foreseen to be in new approaches for research purposes and medicine, providing diagnosis and drug delivery with no invasive methods involved. These technology, in fact, look like therapy but they also represent unique prevention tools. The very same characteristics that make nanomaterial useful in medicine, suggest some precaution: o one hand, thanks to their small size (atomic dimension) nanoparticles can enter cells in the organisms, avoiding natural defenses and move to organs and tissues allowing a target distribution of drugs. On the other hand, these technologies can turn to be harmful to humans (interaction between nanoparticles and the biological human system, high surface- to-mass relation, mobility). Because we are dealing with a rapidly developing technology, where most of the effects are still hard to foresee, potential risks must be considered for both current and future applications. So far, outlining ethical issues means understanding the impact of these technologies on human health.

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Korani, Mitra, Elham Ghazizadeh, Shahla Korani, Zahra Hami et Afshin Mohammadi-Bardbori. « Effects of silver nanoparticles on human health ». European Journal of Nanomedicine 7, n^o 1 (1 janvier 2015). http://dx.doi.org/10.1515/ejnm-2014-0032.

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AbstractThere has been a great deal of attention and research devoted on nanoparticels (NPs) over the last 10 years. From current knowledge in the field of nanotoxicology, it has become evident that the most NPs, if not all are more toxic than bulk materials. The rapid progress and developing has been leading to concerns about the potential risk associated with the use and application of NPs on human health and the environment. Silver nanoparticles (SNPs) are one of the most available and commercially distributed nanomaterials around the world. In order to understand how human health can be affected by SNPs, quantification and detection of SNPs in biological systems have to be conducted in different models. It seems that respiratory and gastrointestinal systems as well as the skin are the major routes of SNPs penetration into the body. Research on SNPs toxicity is mostly conducted in vitro, and the available human and animal data are relatively limited. This review attempts to focus on the characterization and quantification of the potential harmful effects of SNPs on human health.

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Ronge, Emanuel, Thorsten Cottre, Katharina Welter, Vladimir Smirnov, Natalie Jacqueline Ottinger, Friedhelm Finger, Bernhard Kaiser, Wolfram Jaegermann et Christian Jooss. « Stability and Degradation Mechanismof Si-based Photocathodes for Water Splitting with Ultrathin TiO2 Protection Layer ». Zeitschrift für Physikalische Chemie, 30 novembre 2019. http://dx.doi.org/10.1515/zpch-2019-1481.

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Abstract Using transmission and scanning electron microscopy, we study mechanisms which determine the stability of Silicon photocathodes for solar driven water splitting. Such tandem or triple devices can show a promising stability as photocathodes if the semiconductor surface is protected by an ultrathin TiO2 protection layer. Using atomic layer deposition (ALD) with Cl-precursors, 4–7 nm thick TiO2 layers can be grown with high structural perfection. The layer can be electrochemically covered by Pt nanoparticels serving as electro-catalysts. However, Cl-remnants which are typically present in such layers due to incomplete oxidation, are the origin of an electrochemical degradation process. After 1 h AM1.5G illumination in alkaline media, circular shaped corrosion craters appear in the topmost Si layer, although the TiO2 layer is intact in most parts of the crater. The crater development is stopped at local inhomogenities with a higher Pt coverage. The observations suggests that reduced Titanium species due to Cl−/O2− substitution are nucleation sites of the initial corrosion steps due to enhanced solubility of reduced Ti in the electrolyte. This process is followed by electrochemical dissolution of Si, after direct contact between the electrolyte and the top Si layer surface. To increase the stability of TiO2 protected photocathodes, formation of reduced Ti species must be avoided.

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Hahn, Marc Benjamin, et Julián Mateo Zutta Villate. « Combined cell and nanoparticle models for TOPAS to study radiation dose enhancement in cell organelles ». Scientific Reports 11, n^o 1 (24 mars 2021). http://dx.doi.org/10.1038/s41598-021-85964-2.

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AbstractDose enhancement by gold nanoparticles (AuNP) increases the biological effectiveness of radiation damage in biomolecules and tissue. To apply them effectively during cancer therapy their influence on the locally delivered dose has to be determined. Hereby, the AuNP locations strongly influence the energy deposit in the nucleus, mitochondria, membrane and the cytosol of the targeted cells. To estimate these effects, particle scattering simulations are applied. In general, different approaches for modeling the AuNP and their distribution within the cell are possible. In this work, two newly developed continuous and discrete-geometric models for simulations of AuNP in cells are presented. These models are applicable to simulations of internal emitters and external radiation sources. Most of the current studies on AuNP focus on external beam therapy. In contrast, we apply the presented models in Monte-Carlo particle scattering simulations to characterize the energy deposit in cell organelles by radioactive 198AuNP. They emit beta and gamma rays and are therefore considered for applications with solid tumors. Differences in local dose enhancement between randomly distributed and nucleus targeted nanoparticles are compared. Hereby nucleus targeted nanoparticels showed a strong local dose enhancement in the radio sensitive nucleus. These results are the foundation for future experimental work which aims to obtain a mechanistic understanding of cell death induced by radioactive 198Au.

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