Pub Date : 2020-06-17DOI: 10.2174/2210681209666190306145042
Yue Su, A. Yang, Wenzhe Zhang, Shuguang Wen
Copolymer PBB-T with benzo[1,2-d:4,5-d']bis(thiazole) (BBT) as the accepting unit and benzodithiophene (BDT) as the donor unit is a promising candidate for highperformance non-fullerene polymer solar cells (PSCs). So far optical and dielectric constants of the PBB-T are not fully known. PBB-T was synthesized and thin films of PBB-T were prepared. By using the Kramers-Kronig relations and the transmission spectra of the PBB-T films, the optical and dielectric constants, including in absorption coefficient (α(λ)), extinction coefficient (κ(λ)), refractive index (n(λ)), dielectric constant (ε1(λ),ε2(λ)), band gap (Eg) and mobility of the PBB-T films were calculated and analyzed. At 500 nm, α, κ, n, ε1 and ε2 are 1.65×105 cm-1, 0.46, 1.8163, 3.0 and 1.65 respectively. Eg is 2.111 eV. The hole mobility of PBB-T are 2.41×10-5 cm2 V-1 s-1 and 1.71×10-4 cm2 V-1 s-1 for the as-cast film and for the solvent vapor annealed film respectively. The results show that these optical and dielectric constants of the PBB-T films are almost independent on the thicknesses of the films, indicating our results are reliable. The features of the optical and dielectric constants show the PBB-T films are very promising candidates for high-performance non-fullerene PSCs and potential cut-off filter only permitting red and near-infrared light passing. These results are significant for designing optoelectronic devices related to the PBBT thin films.
{"title":"Investigation of Optical and Dielectric Constants of Benzobis(thiazole)- based Copolymer Films","authors":"Yue Su, A. Yang, Wenzhe Zhang, Shuguang Wen","doi":"10.2174/2210681209666190306145042","DOIUrl":"https://doi.org/10.2174/2210681209666190306145042","url":null,"abstract":"Copolymer PBB-T with benzo[1,2-d:4,5-d']bis(thiazole) (BBT) as the accepting unit and benzodithiophene (BDT) as the donor unit is a promising candidate for highperformance non-fullerene polymer solar cells (PSCs). So far optical and dielectric constants of the PBB-T are not fully known. PBB-T was synthesized and thin films of PBB-T were prepared. By using the Kramers-Kronig relations and the transmission spectra of the PBB-T films, the optical and dielectric constants, including in absorption coefficient (α(λ)), extinction coefficient (κ(λ)), refractive index (n(λ)), dielectric constant (ε1(λ),ε2(λ)), band gap (Eg) and mobility of the PBB-T films were calculated and analyzed. At 500 nm, α, κ, n, ε1 and ε2 are 1.65×105 cm-1, 0.46, 1.8163, 3.0 and 1.65 respectively. Eg is 2.111 eV. The hole mobility of PBB-T are 2.41×10-5 cm2 V-1 s-1 and 1.71×10-4 cm2 V-1 s-1 for the as-cast film and for the solvent vapor annealed film respectively. The results show that these optical and dielectric constants of the PBB-T films are almost independent on the thicknesses of the films, indicating our results are reliable. The features of the optical and dielectric constants show the PBB-T films are very promising candidates for high-performance non-fullerene PSCs and potential cut-off filter only permitting red and near-infrared light passing. These results are significant for designing optoelectronic devices related to the PBBT thin films.","PeriodicalId":38913,"journal":{"name":"Nanoscience and Nanotechnology - Asia","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41860643","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-17DOI: 10.2174/2210681209666190220120053
R. Mazumder, S. Paul
Atenolol is a commonly used antihypertensive drug of class III BCS category. It suffers from the problem of poor intestinal absorption or permeability thus low bioavailability. The objective of the present study was to enhance the permeability of atenolol by using a suitable technique, which is economical and devoid of using any organic solvent. The nanocrystal technology by high-pressure homogenization was chosen for this purpose, which is a less expensive and simple method. In this technique, no organic solvent was used. The study was further aimed to characterize prepared nanocrystals in the solid state by Fourier Transform Infrared Spectroscopy (FTIR), Powder X-Ray Diffraction (PXRD) patterns, particle size, zeta potential, %yield and drug permeation study through isolated goat’s intestine. An in-vivo study was carried out to determine the pharmacokinetic property in comparison to pure drug powder using rats as experimental animals. The formulation design was optimized by a 3(2) factorial design. In these designs, two factors namely surfactant amount (X1) and speed of homogenizer (X2) were evaluated on three dependent variables namely particle size (y1), zeta potential (y2) and production yield (y3). PXRD study indicated the presence of high crystal content in the prepared formulation. These nanocrystal formulations were found with a narrow size range from 125 nm to 652 nm and positive zeta potential of 16-18 mV. Optimized formulations showed almost 90% production yield. Permeability study revealed 90.88% drug release for optimized formulation in comparison to the pure drug (31.22%). The FTIR study also exposed that there was no disturbance in the principal peaks of the pure drug atenolol. This confirmed the integrity of the pure drug and its compatibility with the excipients used. A significant increase in the area under the concentration-time curve Cpmax and MRT for nanocrystals was observed in comparison to the pure drug. The higher values of the determination coefficient (R2) of all three parameters indicated the goodness of fit of the 3(2) factorial model. The factorial analysis also revealed that speed of homogenizer had a bigger effect on particle size (-0.2812), zeta potential (-0.0004) and production yield (0.0192) whereas amount of surfactant had a lesser effect on production yield (-370.4401), zeta potential (-43.3651) as well as particle size (-6169.2601). It is concluded that the selected method of nanocrystal formation and its further optimization by factorial design was effective to increase the solubility, as well as permeability of atenolol. Further, the systematic approach of factorial design provides rational evaluation and prediction of nanocrystals formulation on the selected limited number of smart experimentation.
{"title":"Formulation and Evaluation of Atenolol Nanocrystals Using 3(2) Full Factorial Design","authors":"R. Mazumder, S. Paul","doi":"10.2174/2210681209666190220120053","DOIUrl":"https://doi.org/10.2174/2210681209666190220120053","url":null,"abstract":"\u0000\u0000Atenolol is a commonly used antihypertensive drug of class III BCS category. It\u0000suffers from the problem of poor intestinal absorption or permeability thus low bioavailability. The objective\u0000of the present study was to enhance the permeability of atenolol by using a suitable technique, which\u0000is economical and devoid of using any organic solvent.\u0000\u0000\u0000\u0000The nanocrystal technology by high-pressure homogenization was chosen for this purpose,\u0000which is a less expensive and simple method. In this technique, no organic solvent was used. The study\u0000was further aimed to characterize prepared nanocrystals in the solid state by Fourier Transform Infrared\u0000Spectroscopy (FTIR), Powder X-Ray Diffraction (PXRD) patterns, particle size, zeta potential, %yield\u0000and drug permeation study through isolated goat’s intestine. An in-vivo study was carried out to determine\u0000the pharmacokinetic property in comparison to pure drug powder using rats as experimental animals.\u0000The formulation design was optimized by a 3(2) factorial design. In these designs, two factors namely\u0000surfactant amount (X1) and speed of homogenizer (X2) were evaluated on three dependent variables\u0000namely particle size (y1), zeta potential (y2) and production yield (y3).\u0000\u0000\u0000\u0000PXRD study indicated the presence of high crystal content in the prepared formulation. These\u0000nanocrystal formulations were found with a narrow size range from 125 nm to 652 nm and positive\u0000zeta potential of 16-18 mV. Optimized formulations showed almost 90% production yield. Permeability\u0000study revealed 90.88% drug release for optimized formulation in comparison to the pure drug\u0000(31.22%). The FTIR study also exposed that there was no disturbance in the principal peaks of the pure\u0000drug atenolol. This confirmed the integrity of the pure drug and its compatibility with the excipients used.\u0000A significant increase in the area under the concentration-time curve Cpmax and MRT for nanocrystals\u0000was observed in comparison to the pure drug. The higher values of the determination coefficient (R2) of all\u0000three parameters indicated the goodness of fit of the 3(2) factorial model. The factorial analysis also revealed\u0000that speed of homogenizer had a bigger effect on particle size (-0.2812), zeta potential (-0.0004)\u0000and production yield (0.0192) whereas amount of surfactant had a lesser effect on production yield\u0000(-370.4401), zeta potential (-43.3651) as well as particle size (-6169.2601).\u0000\u0000\u0000\u0000 It is concluded that the selected method of nanocrystal formation and its further optimization\u0000by factorial design was effective to increase the solubility, as well as permeability of atenolol. Further,\u0000the systematic approach of factorial design provides rational evaluation and prediction of nanocrystals\u0000formulation on the selected limited number of smart experimentation.\u0000","PeriodicalId":38913,"journal":{"name":"Nanoscience and Nanotechnology - Asia","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45024532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-05-31DOI: 10.2174/2210681209666190627161850
Fateme Mirzajani and Amin Hamidi
In this project, the growth and volatile metabolites profiles of Escherichia coli (E. coli ) and Staphylococcus aureus were monitored under the influence of silver base chemical, nanoparticle and ultra-highly diluted compounds. The treatments were done for 12000 life cycles using silver nanoparticles (AgNPs) as well as ultra-highly diluted Argentum nitricum (Arg-n). Volatile organic metabolites analysis was performed using gas chromatography mass spectrometry (GC-MS). The results indicated that AgNPs treatment made the bacteria resistant and adapted to growth in the nanoparticle condition. The use of ultra-highly diluted Arg-n initially increased growth but it decreased later. Also, with the continuous usage of these materials, no more bacterial growth was observed. The most important compounds produced by E. coli are Acetophenone, Octyl acetate, Styrene, 1,8-cineole, 4-t-butyl-2-(1-methyl-2-nitroethyl)cyclohexane, hexadecane and 2-Undecanol. The main compounds derived from S. aureus are Acetophenone,1,8-cineole, Benzaldehyde, 2-Hexan-1-ol, Tridecanol, Dimethyl Octenal and tetradecane. Acetophenone and 1,8-cineole were common and produced by both organisms. Based on the origin of the produced volatiles, main volatiles percentage of untreated sample is hydrocarbon (>50%), while bacteria treatments convert the ratio in to aldehydes, ketones and alcohols in the case of AgNPs, (>80%) and aldehydes, ketones and terpenes in the case of Arg-n (>70%).
{"title":"Comparison of the Effects of Silver in Nanostructured and Ultrahigh Diluted Form on Growth and Volatile Compounds Produced by Escherichia coli and Staphylococcus aureus","authors":"Fateme Mirzajani and Amin Hamidi","doi":"10.2174/2210681209666190627161850","DOIUrl":"https://doi.org/10.2174/2210681209666190627161850","url":null,"abstract":"\u0000\u0000 In this project, the growth and volatile metabolites profiles of Escherichia\u0000coli (E. coli ) and Staphylococcus aureus were monitored under the influence of silver base chemical,\u0000nanoparticle and ultra-highly diluted compounds.\u0000\u0000\u0000\u0000The treatments were done for 12000 life cycles using silver nanoparticles\u0000(AgNPs) as well as ultra-highly diluted Argentum nitricum (Arg-n). Volatile organic metabolites\u0000analysis was performed using gas chromatography mass spectrometry (GC-MS). The results indicated\u0000that AgNPs treatment made the bacteria resistant and adapted to growth in the nanoparticle\u0000condition. The use of ultra-highly diluted Arg-n initially increased growth but it decreased later.\u0000Also, with the continuous usage of these materials, no more bacterial growth was observed.\u0000\u0000\u0000\u0000The most important compounds produced by E. coli are Acetophenone, Octyl acetate,\u0000Styrene, 1,8-cineole, 4-t-butyl-2-(1-methyl-2-nitroethyl)cyclohexane, hexadecane and 2-Undecanol.\u0000The main compounds derived from S. aureus are Acetophenone,1,8-cineole, Benzaldehyde,\u00002-Hexan-1-ol, Tridecanol, Dimethyl Octenal and tetradecane. Acetophenone and 1,8-cineole were\u0000common and produced by both organisms.\u0000\u0000\u0000\u0000 Based on the origin of the produced volatiles, main volatiles percentage of untreated sample\u0000is hydrocarbon (>50%), while bacteria treatments convert the ratio in to aldehydes, ketones and alcohols\u0000in the case of AgNPs, (>80%) and aldehydes, ketones and terpenes in the case of Arg-n (>70%).\u0000","PeriodicalId":38913,"journal":{"name":"Nanoscience and Nanotechnology - Asia","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49333102","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-05-01DOI: 10.2174/2210681209666181212153701
Anju Arya, T. Chundawat
In recent time, green synthesis of metal nanoparticles is the latest developing technology and received prodigious interest because it is easy, environmentally pristine, non-fouling, antitoxic, and lowcost approach. Green route of biogenic synthesis of metal nanoparticles via microbes such as bacteria, fungi, virus, yeast and algae has the potential to deliver sustainable and enviro safe protocol. Green synthesized metal nanoparticles are the most optimistic and novel agent for various catalytic and biological activities as antibacterial, antiviral, anticancer etc. without any toxic effects. Here, we reviewed algae-mediated green synthesis of metal and metal oxide nanoparticles and their biological activity. Algae are photoautotrophic, eukaryotic, aquatic, unicellular or multicellular organisms. Algae commonly used for biosynthesis because they grow rapidly, their biomass growth on average ten times faster than higher plants and easy to handle experiments with algal species. Different algal strains such as red, green and brown algae are using for the green synthesis of metal nanoparticles. Algae contain bioactive molecules and secondary metabolites that act as reducing, capping and stabilizing agent for manufacturing in nanoparticles. Biogenically synthesized metal and metal oxide nanoparticles characterized by different techniques such as UV-visible spectroscopy, SEM (scanning electron microscopy), HR-TEM (high-resolution transmission electron microscopy), XRD (X-ray diffraction), TGA (thermogravimetric analysis), DLS (dynamic light scattering) zeta potential and exhibited biological activity. In future, research algal production of metal nanoparticles can be explored by the use of different microalgae and their applications in different areas such as biological activity, catalytic activity in the synthesis of organic compounds, medical diagnose and synthesis of nanocomposite, lipid nanoparticles and antibiofilm.
{"title":"Metal Nanoparticles from Algae: A Green Approach for the Synthesis, Characterization and their Biological Activity","authors":"Anju Arya, T. Chundawat","doi":"10.2174/2210681209666181212153701","DOIUrl":"https://doi.org/10.2174/2210681209666181212153701","url":null,"abstract":"\u0000\u0000In recent time, green synthesis of metal nanoparticles is the latest developing technology and\u0000received prodigious interest because it is easy, environmentally pristine, non-fouling, antitoxic, and lowcost\u0000approach. Green route of biogenic synthesis of metal nanoparticles via microbes such as bacteria,\u0000fungi, virus, yeast and algae has the potential to deliver sustainable and enviro safe protocol. Green\u0000synthesized metal nanoparticles are the most optimistic and novel agent for various catalytic and biological\u0000activities as antibacterial, antiviral, anticancer etc. without any toxic effects. Here, we reviewed\u0000algae-mediated green synthesis of metal and metal oxide nanoparticles and their biological activity. Algae\u0000are photoautotrophic, eukaryotic, aquatic, unicellular or multicellular organisms. Algae commonly used\u0000for biosynthesis because they grow rapidly, their biomass growth on average ten times faster than higher\u0000plants and easy to handle experiments with algal species. Different algal strains such as red, green and\u0000brown algae are using for the green synthesis of metal nanoparticles. Algae contain bioactive molecules\u0000and secondary metabolites that act as reducing, capping and stabilizing agent for manufacturing in nanoparticles.\u0000Biogenically synthesized metal and metal oxide nanoparticles characterized by different techniques\u0000such as UV-visible spectroscopy, SEM (scanning electron microscopy), HR-TEM (high-resolution\u0000transmission electron microscopy), XRD (X-ray diffraction), TGA (thermogravimetric analysis), DLS\u0000(dynamic light scattering) zeta potential and exhibited biological activity. In future, research algal production\u0000of metal nanoparticles can be explored by the use of different microalgae and their applications in\u0000different areas such as biological activity, catalytic activity in the synthesis of organic compounds, medical\u0000diagnose and synthesis of nanocomposite, lipid nanoparticles and antibiofilm.\u0000","PeriodicalId":38913,"journal":{"name":"Nanoscience and Nanotechnology - Asia","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46456037","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-05-01DOI: 10.2174/2210681209666190228143636
Niloufar Choubdar and Sara Avizheh
Alzheimer’s Disease (AD) is one of the most common forms of dementia affecting over 46 million people, according to AD International. Over the past few decades, there has been considerable interest in developing nanomedicines. Using nanocarriers, the therapeutic compound could be delivered to the site of action where it gets accumulated. This accumulation, therefore, reduces the required doses for therapy. Alternatively, using nanocarriers decreases the side effects. Nanotechnology has had a great contribution in developing Drug Delivery Systems (DDS). These DDS could function as reservoirs for sustained drug release or control the pharmacokinetics and biodistribution of the drugs. In the current review, we have collected 38 original research articles using nanotechnology as DDS for the clinically used cholinesterase inhibitor drugs donepezil (DPZ), Rivastigmine (Riv), and galantamine (Gal) used for AD treatment from 2002 to 2017 from Scopus and PubMed databases. Regarding DDS used for DPZ, most of the research in recent years dealt with polymeric nanoparticles (NPs) including Poly-D, L-Lactide-Co-Glycolide (PLGA), and chitosans (CHs), then Liposomes (LPs), nanogels, and natural products, respectively. In terms of Riv most of the research performed was focused on polymeric NPs including PLGA, polylactic acid (PLA), Poly-Ε-Caprolactone (PCL), poly-alkyl-cyanoacrylates, CH, gelatin and then LPs. The highest application of NPs in regard to Gal was related to modified LPs and polymeric NPs. Polymeric NPs demonstrate safety, higher stability in biological fluids and against enzymatic metabolism, biocompatibility, bioavailability, and improved encapsulation efficacy. LPs, another major delivery system used, demonstrate biocompatibility, ease of surface modification, and amphiphilic nature.
{"title":"Nanotechnology Based Delivery Systems of Drugs Currently Used to Treat Alzheimer’s Disease","authors":"Niloufar Choubdar and Sara Avizheh","doi":"10.2174/2210681209666190228143636","DOIUrl":"https://doi.org/10.2174/2210681209666190228143636","url":null,"abstract":"\u0000\u0000Alzheimer’s Disease (AD) is one of the most common forms of dementia affecting over\u000046 million people, according to AD International. Over the past few decades, there has been considerable\u0000interest in developing nanomedicines. Using nanocarriers, the therapeutic compound\u0000could be delivered to the site of action where it gets accumulated. This accumulation, therefore,\u0000reduces the required doses for therapy. Alternatively, using nanocarriers decreases the side effects.\u0000Nanotechnology has had a great contribution in developing Drug Delivery Systems (DDS). These\u0000DDS could function as reservoirs for sustained drug release or control the pharmacokinetics and\u0000biodistribution of the drugs. In the current review, we have collected 38 original research articles\u0000using nanotechnology as DDS for the clinically used cholinesterase inhibitor drugs donepezil\u0000(DPZ), Rivastigmine (Riv), and galantamine (Gal) used for AD treatment from 2002 to 2017 from\u0000Scopus and PubMed databases. Regarding DDS used for DPZ, most of the research in recent years\u0000dealt with polymeric nanoparticles (NPs) including Poly-D, L-Lactide-Co-Glycolide (PLGA), and\u0000chitosans (CHs), then Liposomes (LPs), nanogels, and natural products, respectively. In terms of\u0000Riv most of the research performed was focused on polymeric NPs including PLGA, polylactic acid\u0000(PLA), Poly-Ε-Caprolactone (PCL), poly-alkyl-cyanoacrylates, CH, gelatin and then LPs. The highest\u0000application of NPs in regard to Gal was related to modified LPs and polymeric NPs. Polymeric\u0000NPs demonstrate safety, higher stability in biological fluids and against enzymatic metabolism, biocompatibility,\u0000bioavailability, and improved encapsulation efficacy. LPs, another major delivery\u0000system used, demonstrate biocompatibility, ease of surface modification, and amphiphilic nature.\u0000","PeriodicalId":38913,"journal":{"name":"Nanoscience and Nanotechnology - Asia","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41370798","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-11-25DOI: 10.2174/2210681208666180621095241
C. S. Dash, S. Prabaharan
Ion transport in the solid state has been regarded as imperative with regards to high energy density electrochemical storage devices (for instance, batteries) for efficient electric mobility. Of late, there is another niche application involving ion transport in solid state which manifested itself as nonvolatile memory namely memristor. Such memories are classified under the emerging category of novel solid state Resistive Random Access Memories (RRAM). In 2008, HP labs unveiled the first practical memristor device employing TiO2 and non-stoichiometric titania as bilayer stack structure and on both sides of two titania layers platinum (pt) are used as blocking electrode for ions. It is understood that switching fundamentals are correlated to the filamentary conduction in metal oxide memristors owing to the formation and rupture of the filament-like nano-dendrites, one of the key mechanisms widely accepted in the arena of memristor analysis. This paper critically reviews the fundamental materials being employed in novel memristor memories. It is believed that solid electrolytes (fast ion conductors) are the fundamental building blocks of these memories. We have chosen a few archetypes, solid electrolytes are considered and their impact on the state-of-art research in this domain is discussed in detail. An indepth analysis of the fundamentals of resistive switching mechanism involved in various classes of memristive devices viz., Electrochemical Metallization Memories (ECM) and Valence Change Memories (VCM) is elucidated. A few important applications of memristors such as neuristor and artificial synapse in neuromorphic computing are reviewed as well.
{"title":"Science and Technological Understanding of Nano-ionic Resistive Memories (RRAM)","authors":"C. S. Dash, S. Prabaharan","doi":"10.2174/2210681208666180621095241","DOIUrl":"https://doi.org/10.2174/2210681208666180621095241","url":null,"abstract":"\u0000\u0000Ion transport in the solid state has been regarded as imperative with regards to high energy\u0000density electrochemical storage devices (for instance, batteries) for efficient electric mobility. Of late,\u0000there is another niche application involving ion transport in solid state which manifested itself as nonvolatile\u0000memory namely memristor. Such memories are classified under the emerging category of novel\u0000solid state Resistive Random Access Memories (RRAM). In 2008, HP labs unveiled the first practical\u0000memristor device employing TiO2 and non-stoichiometric titania as bilayer stack structure and on both\u0000sides of two titania layers platinum (pt) are used as blocking electrode for ions. It is understood that\u0000switching fundamentals are correlated to the filamentary conduction in metal oxide memristors owing to\u0000the formation and rupture of the filament-like nano-dendrites, one of the key mechanisms widely accepted\u0000in the arena of memristor analysis. This paper critically reviews the fundamental materials being\u0000employed in novel memristor memories. It is believed that solid electrolytes (fast ion conductors) are\u0000the fundamental building blocks of these memories. We have chosen a few archetypes, solid electrolytes\u0000are considered and their impact on the state-of-art research in this domain is discussed in detail. An indepth\u0000analysis of the fundamentals of resistive switching mechanism involved in various classes of\u0000memristive devices viz., Electrochemical Metallization Memories (ECM) and Valence Change Memories\u0000(VCM) is elucidated. A few important applications of memristors such as neuristor and artificial\u0000synapse in neuromorphic computing are reviewed as well.\u0000","PeriodicalId":38913,"journal":{"name":"Nanoscience and Nanotechnology - Asia","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46470702","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-04DOI: 10.2174/2210681208666180626162916
M. Parvathi, A. Leelaratanam, C. RajuM
Convective heat and mass transfer in nanofluids is a topic of major contemporary interest in both science and technology. In view of this, an unsteady MHD free convective flow of nanofluids through a porous medium bound by a moving vertical semi-infinite permeable flat plate with a constant heat source and convective boundary condition in a rotating frame of reference is studied theoretically. The novelty is the consideration of constant heat source and convective boundary condition in a rotating frame. The velocity along the plate i.e., slip velocity is assumed to oscillate in time with constant frequency so that the solutions of the boundary layer are of the same oscillatory type. The dimensionless governing equations for this investigation are solved analytically using small perturbation approximation. Two types of nanofluids, namely Cu-water and Al2O3-water are used. The effects of various parameters on the flow, heat and mass transfer characteristics are discussed through graphs and tables. An increase in the convective parameter and nanoparticle volume fraction leads to increase the thermal boundary layer thickness but opposite effect occurs for heat generation.
{"title":"Heat and Mass Transfer Characteristics of Nanofluids in a Rotating System: A Convective Boundary Layer Flow","authors":"M. Parvathi, A. Leelaratanam, C. RajuM","doi":"10.2174/2210681208666180626162916","DOIUrl":"https://doi.org/10.2174/2210681208666180626162916","url":null,"abstract":"\u0000\u0000Convective heat and mass transfer in nanofluids is a topic of major contemporary\u0000interest in both science and technology. In view of this, an unsteady MHD free convective flow of\u0000nanofluids through a porous medium bound by a moving vertical semi-infinite permeable flat plate with\u0000a constant heat source and convective boundary condition in a rotating frame of reference is studied\u0000theoretically.\u0000\u0000\u0000\u0000The novelty is the consideration of constant heat source and convective boundary condition\u0000in a rotating frame. The velocity along the plate i.e., slip velocity is assumed to oscillate in time\u0000with constant frequency so that the solutions of the boundary layer are of the same oscillatory type. The\u0000dimensionless governing equations for this investigation are solved analytically using small perturbation\u0000approximation. Two types of nanofluids, namely Cu-water and Al2O3-water are used.\u0000\u0000\u0000\u0000 The effects of various parameters on the flow, heat and mass transfer characteristics are discussed\u0000through graphs and tables.\u0000\u0000\u0000\u0000An increase in the convective parameter and nanoparticle volume fraction leads to increase\u0000the thermal boundary layer thickness but opposite effect occurs for heat generation.\u0000","PeriodicalId":38913,"journal":{"name":"Nanoscience and Nanotechnology - Asia","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44076459","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-04DOI: 10.2174/1573413714666180716154648
Rakesh Sharma, J. Singh, A. Bhatia
An alternative source of synythesis of nanoparticles is plant extract rather than chemical methods. This is because of presence of secondary metabolites or reducing agents in plant extract which are responsible for nanoparticles synthesis. In bioaccumulation, this synthesis depends upon the availability of particular enzymes or protein in plant extract. Considering the therapeutic potentials of nanoparticles, this work has been designed to find out antibacterial activity of silver nanoparticles. Objectives of this work are - preparation of silver nanoparticles chemically and biologically, characterisation of nanoparticles and evaluation of their antibacterial activities against E. coli. Comparision of antibacterial properties were made among NaBH4- AgNPs, Azadirachta indica (Neem) extract AgNPs and Brassica oleracea (Cauliflower) extract AgNPs. UV- absorption spectra of chemically and biologically synthesized AgNPs at different time intervals were measured using UV-Visible spectrophotometer. Particle size of AgNPs was measured by dynamic laser scattering technique (DLS) using Malvern Aimil Zetasizer. The obtained silver nanoparticles were of sizes between 10 nm and 100 nm. It was clear from antibacterial activities that biologically synthesized AgNPs were more effective against E. coli than chemically synthesized AgNPs.
{"title":"Azadirachta Indica and Brassica Oleracea Mediated Green Synthesis vs. Chemical Synthesis of Silver Nanoparticles and their Antibacterial Properties","authors":"Rakesh Sharma, J. Singh, A. Bhatia","doi":"10.2174/1573413714666180716154648","DOIUrl":"https://doi.org/10.2174/1573413714666180716154648","url":null,"abstract":"An alternative source of synythesis of nanoparticles is plant extract rather than\u0000chemical methods. This is because of presence of secondary metabolites or reducing agents in plant extract\u0000which are responsible for nanoparticles synthesis. In bioaccumulation, this synthesis depends upon\u0000the availability of particular enzymes or protein in plant extract.\u0000\u0000\u0000\u0000Considering the therapeutic potentials of nanoparticles, this work has been designed\u0000to find out antibacterial activity of silver nanoparticles. Objectives of this work are - preparation\u0000of silver nanoparticles chemically and biologically, characterisation of nanoparticles and evaluation of\u0000their antibacterial activities against E. coli. Comparision of antibacterial properties were made among\u0000NaBH4- AgNPs, Azadirachta indica (Neem) extract AgNPs and Brassica oleracea (Cauliflower) extract\u0000AgNPs. UV- absorption spectra of chemically and biologically synthesized AgNPs at different time intervals\u0000were measured using UV-Visible spectrophotometer. Particle size of AgNPs was measured by\u0000dynamic laser scattering technique (DLS) using Malvern Aimil Zetasizer.\u0000\u0000\u0000\u0000The obtained silver nanoparticles were of sizes between 10 nm and 100 nm.\u0000\u0000\u0000\u0000 It was clear from antibacterial activities that biologically synthesized AgNPs were more\u0000effective against E. coli than chemically synthesized AgNPs.","PeriodicalId":38913,"journal":{"name":"Nanoscience and Nanotechnology - Asia","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43545727","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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