Pub Date : 2022-11-18DOI: 10.3389/fnano.2022.1072227
Camil Rex M, A. Mukherjee
COVID-19 is one of the serious catastrophes that have a substantial influence on human health and the environment. Diverse preventive actions were implemented globally to limit its spread and transmission. Personnel protective equipment (PPE) was an important part of these control approaches. But unfortunately, these types of PPE mainly comprise plastics, which sparked challenges in the management of plastic waste. Disposable face masks (DFM) are one of the efficient strategies used across the world to ward off disease transmission. DFMs can contribute to micro and nano plastic pollution as the plastic present in the mask may degrade when exposed to certain environmental conditions. Microplastics (MPs) can enter the food chain and devastate human health. Recognizing the possible environmental risks associated with the inappropriate disposal of masks, it is crucial to avert it from becoming the next plastic crisis. To address this environmental threat, titanium dioxide (TiO2)-based photocatalytic degradation (PCD) of MPs is one of the promising approaches. TiO2-based photocatalysts exhibit excellent plastic degradation potential due to their outstanding photocatalytic ability, cost efficiency, chemical, and thermal stability. In this review, we have discussed the reports on COVID-19 waste generation, the limitation of current waste management techniques, and the environmental impact of MPs leachates from DFMs. Mainly, the prominence of TiO2 in the PCD and the applications of TiO2-based photocatalysts in MPs degradation are the prime highlights of this review. Additionally, various synthesis methods to enhance the photocatalytic performance of TiO2 and the mechanism of PCD are also discussed. Furthermore, current challenges and the future research perspective on the improvement of this approach have been proposed.
{"title":"Prospects of TiO2-based photocatalytic degradation of microplastic leachates related disposable facemask, a major COVID-19 waste","authors":"Camil Rex M, A. Mukherjee","doi":"10.3389/fnano.2022.1072227","DOIUrl":"https://doi.org/10.3389/fnano.2022.1072227","url":null,"abstract":"COVID-19 is one of the serious catastrophes that have a substantial influence on human health and the environment. Diverse preventive actions were implemented globally to limit its spread and transmission. Personnel protective equipment (PPE) was an important part of these control approaches. But unfortunately, these types of PPE mainly comprise plastics, which sparked challenges in the management of plastic waste. Disposable face masks (DFM) are one of the efficient strategies used across the world to ward off disease transmission. DFMs can contribute to micro and nano plastic pollution as the plastic present in the mask may degrade when exposed to certain environmental conditions. Microplastics (MPs) can enter the food chain and devastate human health. Recognizing the possible environmental risks associated with the inappropriate disposal of masks, it is crucial to avert it from becoming the next plastic crisis. To address this environmental threat, titanium dioxide (TiO2)-based photocatalytic degradation (PCD) of MPs is one of the promising approaches. TiO2-based photocatalysts exhibit excellent plastic degradation potential due to their outstanding photocatalytic ability, cost efficiency, chemical, and thermal stability. In this review, we have discussed the reports on COVID-19 waste generation, the limitation of current waste management techniques, and the environmental impact of MPs leachates from DFMs. Mainly, the prominence of TiO2 in the PCD and the applications of TiO2-based photocatalysts in MPs degradation are the prime highlights of this review. Additionally, various synthesis methods to enhance the photocatalytic performance of TiO2 and the mechanism of PCD are also discussed. Furthermore, current challenges and the future research perspective on the improvement of this approach have been proposed.","PeriodicalId":34432,"journal":{"name":"Frontiers in Nanotechnology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47396678","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 : 2022-11-11DOI: 10.3389/fnano.2022.1049599
Mariana Oliveira Vasconcelos, L. A. D. Silva, A. Sousa-Junior, Thaís Rosa Marques dos Santos, Carla Afonso da Silva, M. Valadares, E. Lima
Guided tissue regeneration (GTR) is a dentistry technique based on the use of polymeric biomembranes as physical barriers for selective cell exclusion, directing the growth of gingival tissue, bone tissue, and periodontal ligaments in a region previously affected by periodontitis. Postoperative pain and microbial infection constitute, however, two major challenges to be tackled right after implantation. To address these challenges, we prepared and characterized eight chitosan/hyaluronic acid/glycerol (CS/HA/GL) bioresorbable membranes embedded with lidocaine- and chloramphenicol-loaded polycaprolactone nanoparticles (LDNP and CHNP, respectively), combining the local anesthetic effects of lidocaine with the antibacterial effects of chloramphenicol. The formulations were prepared with varying amounts of CS, HA, GL, LDNP, and CHNP. As a plasticizing agent, GL could modulate the samples mechanical properties such as thickness, morphology, tensile strength, elongation at break, as well as swelling and degradation in simulated saliva. Two samples exhibited greater resistance to biodegradation and were selected for further studies. Their drug release profiles indicated that LDNP and CHNP first detach from the membrane matrix, and a zeroth order drug release kinetics from the detached NPs dominates the overall process thereafter, with lidocaine being released 3 times faster than chloramphenicol, in a controlled and sustained rate over time. Drug encapsulation efficiency was such that optimal samples exhibited bactericidal activity (inhibition halos) against gram-positive S. aureus and gram-negative A. actinomycetemcomitans strains similar to that observed for free chloramphenicol. Finally, one of these samples showed no intrinsic toxicity against healthy mammalian model cells (99% viability for the unloaded membrane; 80% viability for the fully LDNP- and CHNP-loaded membrane), and may now be further optimized as a drug-eluting biomembrane with potential for GTR.
{"title":"Lidocaine- and chloramphenicol-loaded nanoparticles embedded in a chitosan/hyaluronic acid/glycerol matrix: Drug-eluting biomembranes with potential for guided tissue regeneration","authors":"Mariana Oliveira Vasconcelos, L. A. D. Silva, A. Sousa-Junior, Thaís Rosa Marques dos Santos, Carla Afonso da Silva, M. Valadares, E. Lima","doi":"10.3389/fnano.2022.1049599","DOIUrl":"https://doi.org/10.3389/fnano.2022.1049599","url":null,"abstract":"Guided tissue regeneration (GTR) is a dentistry technique based on the use of polymeric biomembranes as physical barriers for selective cell exclusion, directing the growth of gingival tissue, bone tissue, and periodontal ligaments in a region previously affected by periodontitis. Postoperative pain and microbial infection constitute, however, two major challenges to be tackled right after implantation. To address these challenges, we prepared and characterized eight chitosan/hyaluronic acid/glycerol (CS/HA/GL) bioresorbable membranes embedded with lidocaine- and chloramphenicol-loaded polycaprolactone nanoparticles (LDNP and CHNP, respectively), combining the local anesthetic effects of lidocaine with the antibacterial effects of chloramphenicol. The formulations were prepared with varying amounts of CS, HA, GL, LDNP, and CHNP. As a plasticizing agent, GL could modulate the samples mechanical properties such as thickness, morphology, tensile strength, elongation at break, as well as swelling and degradation in simulated saliva. Two samples exhibited greater resistance to biodegradation and were selected for further studies. Their drug release profiles indicated that LDNP and CHNP first detach from the membrane matrix, and a zeroth order drug release kinetics from the detached NPs dominates the overall process thereafter, with lidocaine being released 3 times faster than chloramphenicol, in a controlled and sustained rate over time. Drug encapsulation efficiency was such that optimal samples exhibited bactericidal activity (inhibition halos) against gram-positive S. aureus and gram-negative A. actinomycetemcomitans strains similar to that observed for free chloramphenicol. Finally, one of these samples showed no intrinsic toxicity against healthy mammalian model cells (99% viability for the unloaded membrane; 80% viability for the fully LDNP- and CHNP-loaded membrane), and may now be further optimized as a drug-eluting biomembrane with potential for GTR.","PeriodicalId":34432,"journal":{"name":"Frontiers in Nanotechnology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42426752","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 : 2022-11-03DOI: 10.3389/fnano.2022.1055545
Taylor Wilson, B. Cambou
In this paper, we present the characterization of pre-formed resistive random access memories to design physical unclonable functions and experimentally validate inherent properties such as tamper sensitivity and a self-destroy mode. The physical unclonable functions were tested for repetitive use, temperature effects, and aging. The variations during successive response generation cycles and drift rates are quantized to explore their reliability. We define tamper-sensitivity as the ability to detect tampering attacks. To establish tamper sensitivity, the cells were characterized for higher current sweeps, and the injected current at which they break down is extracted and analyzed to determine suitable operating ranges. Our experimental results show that at least 91% of the cells can generate keys protected by the scheme, while 22% of the sensing elements are triggered. Finally, the cells were characterized for high Voltage sweeps to be able to destroy the physical unclonable functions on-demand when tampering activity is detected. A fixed Voltage of 1.9 V is enough to destroy the entire array.
{"title":"Tamper-sensitive pre-formed ReRAM-based PUFs: Methods and experimental validation","authors":"Taylor Wilson, B. Cambou","doi":"10.3389/fnano.2022.1055545","DOIUrl":"https://doi.org/10.3389/fnano.2022.1055545","url":null,"abstract":"In this paper, we present the characterization of pre-formed resistive random access memories to design physical unclonable functions and experimentally validate inherent properties such as tamper sensitivity and a self-destroy mode. The physical unclonable functions were tested for repetitive use, temperature effects, and aging. The variations during successive response generation cycles and drift rates are quantized to explore their reliability. We define tamper-sensitivity as the ability to detect tampering attacks. To establish tamper sensitivity, the cells were characterized for higher current sweeps, and the injected current at which they break down is extracted and analyzed to determine suitable operating ranges. Our experimental results show that at least 91% of the cells can generate keys protected by the scheme, while 22% of the sensing elements are triggered. Finally, the cells were characterized for high Voltage sweeps to be able to destroy the physical unclonable functions on-demand when tampering activity is detected. A fixed Voltage of 1.9 V is enough to destroy the entire array.","PeriodicalId":34432,"journal":{"name":"Frontiers in Nanotechnology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48448483","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 : 2022-11-01DOI: 10.3389/fnano.2022.1026286
A. Kersch, Richard Ganser, Maximilian Trien
Fluorite-structured hafnium and zirconia require different, complementary characterization methods to identify the numerous metastable phases. This is because of the many possible positions of the oxygen ions, which are difficult to observe directly. Ab initio simulations are useful to probe the corresponding XRD, Raman, and infrared spectra for fingerprints. However, the predictive power of theoretical methods is limited both by model errors and by boundary conditions such as defects, stresses, and morphology that are difficult to detect. We first consider the calculation of Raman and infrared spectra of the most interesting undoped phases of HfO2 and ZrO2, compare the results with known results, and discuss the uncertainties. Next, we consider the possibilities of classifying the phases using X-ray diffraction. To this end, we introduce the effects of doping, which increases the uncertainty due to structural disorder. For illustration, we examine a large data set of doped structures obtained with ab initio calculations. To make an unbiased assignment of phases, we use machine learning methods with clusters. The limits of X-ray diffraction spectroscopy are reached when phase mixtures are present. Resolution of single-phase polycrystalline samples may only be possible here if these three characterization methods are used.
{"title":"Simulation of XRD, Raman and IR spectrum for phase identification in doped HfO2 and ZrO2","authors":"A. Kersch, Richard Ganser, Maximilian Trien","doi":"10.3389/fnano.2022.1026286","DOIUrl":"https://doi.org/10.3389/fnano.2022.1026286","url":null,"abstract":"Fluorite-structured hafnium and zirconia require different, complementary characterization methods to identify the numerous metastable phases. This is because of the many possible positions of the oxygen ions, which are difficult to observe directly. Ab initio simulations are useful to probe the corresponding XRD, Raman, and infrared spectra for fingerprints. However, the predictive power of theoretical methods is limited both by model errors and by boundary conditions such as defects, stresses, and morphology that are difficult to detect. We first consider the calculation of Raman and infrared spectra of the most interesting undoped phases of HfO2 and ZrO2, compare the results with known results, and discuss the uncertainties. Next, we consider the possibilities of classifying the phases using X-ray diffraction. To this end, we introduce the effects of doping, which increases the uncertainty due to structural disorder. For illustration, we examine a large data set of doped structures obtained with ab initio calculations. To make an unbiased assignment of phases, we use machine learning methods with clusters. The limits of X-ray diffraction spectroscopy are reached when phase mixtures are present. Resolution of single-phase polycrystalline samples may only be possible here if these three characterization methods are used.","PeriodicalId":34432,"journal":{"name":"Frontiers in Nanotechnology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46329006","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 : 2022-11-01DOI: 10.3389/fnano.2022.1055708
Vishal Chaudhary
Current theranostics for neurodegenerative diseases (NDD) management are majorly symptomatic due to a lack of identification of early-stage biomarkers and the inefficiency of drugs to penetrate through the blood-brain barrier. Recently, the Neuro-nanotechnology interface has emerged as a potential strategy for diagnosis, monitoring, and treatment of NDDs owing to smaller particle size, high specific surface area, tunable physicochemical attributes and rich surface functionalities. However, toxicity and biocompatibility are two significant challenges restricting their commercial prospect in NDD management. On the contrary, green nanosystems fabricated using plant extracts, microorganisms, biome-based precursors, repurposed-byproducts, exosomes, and protein-based bio-nanomaterials are economical, eco-friendly, biocompatible and renewable due to the abundance of biodiversity. This prospect explores the novel and cutting-edge interface of green nanosystems and NDDs for developing diagnostic and implantable devices, targeted drug delivery strategies, surgical prostheses, therapeutics, treatment, nanoscaffolds for neurogeneration, and immunity development. Besides, it discusses the challenges, alternate solutions and advanced prospects of green nanosystems with the integration of modern-age technologies for the development of sustainable green Neuro-nanotechnology for efficient management of NDDs. Graphical Abstract
{"title":"Prospects of green nanotechnology for efficient management of neurodegenerative diseases","authors":"Vishal Chaudhary","doi":"10.3389/fnano.2022.1055708","DOIUrl":"https://doi.org/10.3389/fnano.2022.1055708","url":null,"abstract":"Current theranostics for neurodegenerative diseases (NDD) management are majorly symptomatic due to a lack of identification of early-stage biomarkers and the inefficiency of drugs to penetrate through the blood-brain barrier. Recently, the Neuro-nanotechnology interface has emerged as a potential strategy for diagnosis, monitoring, and treatment of NDDs owing to smaller particle size, high specific surface area, tunable physicochemical attributes and rich surface functionalities. However, toxicity and biocompatibility are two significant challenges restricting their commercial prospect in NDD management. On the contrary, green nanosystems fabricated using plant extracts, microorganisms, biome-based precursors, repurposed-byproducts, exosomes, and protein-based bio-nanomaterials are economical, eco-friendly, biocompatible and renewable due to the abundance of biodiversity. This prospect explores the novel and cutting-edge interface of green nanosystems and NDDs for developing diagnostic and implantable devices, targeted drug delivery strategies, surgical prostheses, therapeutics, treatment, nanoscaffolds for neurogeneration, and immunity development. Besides, it discusses the challenges, alternate solutions and advanced prospects of green nanosystems with the integration of modern-age technologies for the development of sustainable green Neuro-nanotechnology for efficient management of NDDs. Graphical Abstract","PeriodicalId":34432,"journal":{"name":"Frontiers in Nanotechnology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41481089","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 : 2022-10-31DOI: 10.3389/fnano.2022.1008266
Youngseok Kim, T. Gokmen, H. Miyazoe, P. Solomon, Seyoung Kim, Asit Ray, J. Doevenspeck, R. S. Khan, V. Narayanan, T. Ando
We demonstrate a modified stochastic gradient (Tiki-Taka v2 or TTv2) algorithm for deep learning network training in a cross-bar array architecture based on ReRAM cells. There have been limited discussions on cross-bar arrays for training applications due to the challenges in the switching behavior of nonvolatile memory materials. TTv2 algorithm is known to overcome the device non-idealities for deep learning training. We demonstrate the feasibility of the algorithm for a linear regression task using 1R and 1T1R ReRAM devices. Using the measured device properties, we project the performance of a long short-term memory (LSTM) network with 78 K parameters. We show that TTv2 algorithm relaxes the criteria for symmetric device update response. In addition, further optimization of the algorithm increases noise robustness and significantly reduces the required number of states, thereby drastically improving the model accuracy even with non-ideal devices and achieving the test error close to that of the conventional learning algorithm with an ideal device.
我们展示了一种改进的随机梯度（Tiki Taka v2或TTv2）算法，用于基于ReRAM单元的横杆阵列结构中的深度学习网络训练。由于非易失性存储器材料的开关行为方面的挑战，关于用于训练应用的横杆阵列的讨论有限。已知TTv2算法可以克服深度学习训练的设备非理想性。我们使用1R和1T1R ReRAM设备证明了该算法用于线性回归任务的可行性。使用测量的设备特性，我们预测了具有78K参数的长短期存储器（LSTM）网络的性能。我们证明了TTv2算法放宽了对称设备更新响应的标准。此外，算法的进一步优化提高了噪声鲁棒性，并显著减少了所需的状态数量，从而即使在非理想设备的情况下也能大幅提高模型精度，并实现了与理想设备的传统学习算法接近的测试误差。
{"title":"Neural network learning using non-ideal resistive memory devices","authors":"Youngseok Kim, T. Gokmen, H. Miyazoe, P. Solomon, Seyoung Kim, Asit Ray, J. Doevenspeck, R. S. Khan, V. Narayanan, T. Ando","doi":"10.3389/fnano.2022.1008266","DOIUrl":"https://doi.org/10.3389/fnano.2022.1008266","url":null,"abstract":"We demonstrate a modified stochastic gradient (Tiki-Taka v2 or TTv2) algorithm for deep learning network training in a cross-bar array architecture based on ReRAM cells. There have been limited discussions on cross-bar arrays for training applications due to the challenges in the switching behavior of nonvolatile memory materials. TTv2 algorithm is known to overcome the device non-idealities for deep learning training. We demonstrate the feasibility of the algorithm for a linear regression task using 1R and 1T1R ReRAM devices. Using the measured device properties, we project the performance of a long short-term memory (LSTM) network with 78 K parameters. We show that TTv2 algorithm relaxes the criteria for symmetric device update response. In addition, further optimization of the algorithm increases noise robustness and significantly reduces the required number of states, thereby drastically improving the model accuracy even with non-ideal devices and achieving the test error close to that of the conventional learning algorithm with an ideal device.","PeriodicalId":34432,"journal":{"name":"Frontiers in Nanotechnology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41312743","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 : 2022-10-26DOI: 10.3389/fnano.2022.1034795
Q. Mao, Yuwei Zhang, M. Kowalik, Nadire Nayir, M. Chandross, A. V. van Duin
An atomistic modeling tool is essential to an in-depth understanding upon surface reactions of transition metal dichalcogenides (TMDs), such as molybdenum disulfide (MoS2), with the presence of compositing agents, including Ti and Au, under different environmental exposures. We report a new ReaxFF reactive force field parameter set for Mo, Ti, Au, O, S, and H interactions. We apply the force field in a series of molecular dynamics (MD) simulations to unravel the impact of the Ti dopant on the oxidation/hydrogenation behaviors of MoS2 surface. The simulation results reveal that, in the absence of Ti clusters, the MoS2 surface is ruptured and oxidized at elevated temperatures through a process of adsorption followed by dissociation of the O2 molecules on the MoS2 surface during the temperature ramp. When the MoS2 surface is exposed to H2O molecules, surface hydrogenation is most favored, followed by oxidation, then hydroxylation. The introduction of Ti clusters to the systems mitigates the oxidation/hydrogenation of MoS2 at a low or intermediate temperature by capturing the O2/H2O molecules and locking the O/H-related radicals inside the clusters. However, OH− and H3O+ are emitted from the Ti clusters in the H2O environment as temperature rises, and the accelerating hydrogenation of MoS2 is consequently observed at an ultra-high temperature. These findings indicate an important but complex role of Ti dopants in mitigating the oxidation and hydrogenation of MoS2 under different environmental exposures. The possible mechanisms of oxidation and hydrogenation revealed by MD simulations can give an insight to the design of oxidation resistant TMDs and can be useful to the optical, electronic, magnetic, catalytic, and energy harvesting industries.
{"title":"Oxidation and hydrogenation of monolayer MoS2 with compositing agent under environmental exposure: The ReaxFF Mo/Ti/Au/O/S/H force field development and applications","authors":"Q. Mao, Yuwei Zhang, M. Kowalik, Nadire Nayir, M. Chandross, A. V. van Duin","doi":"10.3389/fnano.2022.1034795","DOIUrl":"https://doi.org/10.3389/fnano.2022.1034795","url":null,"abstract":"An atomistic modeling tool is essential to an in-depth understanding upon surface reactions of transition metal dichalcogenides (TMDs), such as molybdenum disulfide (MoS2), with the presence of compositing agents, including Ti and Au, under different environmental exposures. We report a new ReaxFF reactive force field parameter set for Mo, Ti, Au, O, S, and H interactions. We apply the force field in a series of molecular dynamics (MD) simulations to unravel the impact of the Ti dopant on the oxidation/hydrogenation behaviors of MoS2 surface. The simulation results reveal that, in the absence of Ti clusters, the MoS2 surface is ruptured and oxidized at elevated temperatures through a process of adsorption followed by dissociation of the O2 molecules on the MoS2 surface during the temperature ramp. When the MoS2 surface is exposed to H2O molecules, surface hydrogenation is most favored, followed by oxidation, then hydroxylation. The introduction of Ti clusters to the systems mitigates the oxidation/hydrogenation of MoS2 at a low or intermediate temperature by capturing the O2/H2O molecules and locking the O/H-related radicals inside the clusters. However, OH− and H3O+ are emitted from the Ti clusters in the H2O environment as temperature rises, and the accelerating hydrogenation of MoS2 is consequently observed at an ultra-high temperature. These findings indicate an important but complex role of Ti dopants in mitigating the oxidation and hydrogenation of MoS2 under different environmental exposures. The possible mechanisms of oxidation and hydrogenation revealed by MD simulations can give an insight to the design of oxidation resistant TMDs and can be useful to the optical, electronic, magnetic, catalytic, and energy harvesting industries.","PeriodicalId":34432,"journal":{"name":"Frontiers in Nanotechnology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42649030","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 : 2022-10-25DOI: 10.3389/fnano.2022.1034357
He Kang, Nayeon Kim, Seonuk Jeon, Hyun Wook Kim, E. Hong, Seyoung Kim, Jiyong Woo
While electro-chemical RAM (ECRAM)-based cross-point synaptic arrays are considered to be promising candidates for energy-efficient neural network computational hardware, array-level analyses to achieve energy-efficient update operations have not yet been performed. In this work, we fabricated CuOx/HfOx/WOx ECRAM arrays and demonstrated linear and symmetrical weight update capabilities in both fully parallel and sequential update operations. Based on the experimental measurements, we showed that the source-drain leakage current (ISD) through the unselected ECRAM cells and resultant energy consumption—which had been neglected thus far—contributed a large portion to the total update energy. We showed that both device engineering to reduce ISD and the selection of an update scheme—for example, column-by-column—that avoided ISD intervention via unselected cells were key to enable energy-efficient neuromorphic computing.
{"title":"Analysis of electro-chemical RAM synaptic array for energy-efficient weight update","authors":"He Kang, Nayeon Kim, Seonuk Jeon, Hyun Wook Kim, E. Hong, Seyoung Kim, Jiyong Woo","doi":"10.3389/fnano.2022.1034357","DOIUrl":"https://doi.org/10.3389/fnano.2022.1034357","url":null,"abstract":"While electro-chemical RAM (ECRAM)-based cross-point synaptic arrays are considered to be promising candidates for energy-efficient neural network computational hardware, array-level analyses to achieve energy-efficient update operations have not yet been performed. In this work, we fabricated CuOx/HfOx/WOx ECRAM arrays and demonstrated linear and symmetrical weight update capabilities in both fully parallel and sequential update operations. Based on the experimental measurements, we showed that the source-drain leakage current (ISD) through the unselected ECRAM cells and resultant energy consumption—which had been neglected thus far—contributed a large portion to the total update energy. We showed that both device engineering to reduce ISD and the selection of an update scheme—for example, column-by-column—that avoided ISD intervention via unselected cells were key to enable energy-efficient neuromorphic computing.","PeriodicalId":34432,"journal":{"name":"Frontiers in Nanotechnology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42416615","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 : 2022-10-24DOI: 10.3389/fnano.2022.1042338
Deepasree K, S. Venugopal
Diseases have always been a disconcerting issue and have changed into being an inevitable member of the world’s population. Medical advancements have brought in improved treatments for particular ailments, but unfortunately those betterments have resulted in either side effects or turned out futile to a certain extent. The emergence of nanotechnology has considerably benefitted medical experts in disease diagnosis and therapeutics. Currently, an expansive range of nanoparticles is being explored for their effectiveness in therapies, and one among them is selenium nanoparticles (SeNPs). Nano-selenium exhibits significant properties which make it best suited for this purpose. The article highlights the key role of SeNPs in treating major diseases like cancer, diabetes, and microbial infections.
{"title":"Therapeutic potential of selenium nanoparticles","authors":"Deepasree K, S. Venugopal","doi":"10.3389/fnano.2022.1042338","DOIUrl":"https://doi.org/10.3389/fnano.2022.1042338","url":null,"abstract":"Diseases have always been a disconcerting issue and have changed into being an inevitable member of the world’s population. Medical advancements have brought in improved treatments for particular ailments, but unfortunately those betterments have resulted in either side effects or turned out futile to a certain extent. The emergence of nanotechnology has considerably benefitted medical experts in disease diagnosis and therapeutics. Currently, an expansive range of nanoparticles is being explored for their effectiveness in therapies, and one among them is selenium nanoparticles (SeNPs). Nano-selenium exhibits significant properties which make it best suited for this purpose. The article highlights the key role of SeNPs in treating major diseases like cancer, diabetes, and microbial infections.","PeriodicalId":34432,"journal":{"name":"Frontiers in Nanotechnology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48743587","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 : 2022-10-21DOI: 10.3389/fnano.2022.1006628
Nimish Gupta, G. Gupta, Dilpreet K Singh
Topical drug delivery presents a novel substitute to the conventional drug-distribution routes of oral delivery and injection. Apart from the simplicity and non-invasiveness, the skin also serves as a “reservoir” that sustains administration over a period of days. Nanocarriers provide new potential for the treatment of skin disease. The skin’s barrier function offers a considerable obstacle for the potential nanocarriers to infiltrate into the tissue. However, the barrier is partially weakened in case of damage or inflammation, as in the case of skin cancer. Nanoparticles may promote the penetration of the skin. Extensive research has been done into producing nanoparticles for topical distribution; nevertheless, relatively little progress has been achieved in transferring them to the clinic for treating skin malignancies. The prior art features the critical concepts of skin malignancies and techniques in current clinical care. The present review gives a complete viewpoint of the numerous nanoparticle technologies studied for the topical treatment of skin malignancies and outlines the hurdles that hamper its advancement from the bench to the bedside. The review also intends to give knowledge of the routes that control nanoparticle penetration into the skin and their interactions inside the tissue.
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