In this work,an alternative alkali-activated cement(AAC)made of ladle slag precursor mixed with sodium hydroxide and sodium silicate has been developed to enhance the bearing capacity of estuarine soils in coastal con...In this work,an alternative alkali-activated cement(AAC)made of ladle slag precursor mixed with sodium hydroxide and sodium silicate has been developed to enhance the bearing capacity of estuarine soils in coastal conditions via deep soil mixing(DSM).The AAC was optimized to use a low reactivity precursor(ladle slag)and to deal with a contaminated high-water content natural sediment cured under water.The material performance was analysed by comparison to a mixture made with Portland cement and cured in the same conditions.Flexural and unconfined compressive strength tests as well as seismic waves measurements after 3-,7-,14-and 28-d curing were performed to obtain a relationship between elastic stiffness and strength with curing time for both mixtures.Remarkably,the AAC mix demonstrated superior strength results,exhibiting almost double flexural and compressive strengths after 28 d compared to the Portland cement mix.The AAC mix also showed a higher rate of stiffness increase than the Portland cement mix,which has a higher initial stiffness at young ages but lower stiffness evolution.Leachate analysis confirmed that the proposed AAC could effectively immobilise any contaminants from soil or precursors.The effect of curing under stress was analysed in triaxial compression tests and found to be insignificant,indicating that laboratory data obtained without stress curing can represent the material's behaviour in a DSM column,which will cure under the weight of the column.展开更多
Laser Induced Breakdown Spectroscopic(LIBS)technique was used to detect calcium and silicon in an unknown sample.In this method plasma was generated by Nd∶YAG laser of wavelength 1 064 nm with energy 400 mJ and pulse...Laser Induced Breakdown Spectroscopic(LIBS)technique was used to detect calcium and silicon in an unknown sample.In this method plasma was generated by Nd∶YAG laser of wavelength 1 064 nm with energy 400 mJ and pulse duration between 5~10ns.The method was applied for the qualitative as well as quantitative analysis.In the qualitative analysis,the electron number density(Ne)of plasma containing calcium and silicon is determined showing that Neof neutral particles is equivalent to 1016(cm-3)whereas for ionized particles it is 1017(cm-3).Plasma temperature is measured using Boltzmann plot method which must be greater than 10 000 k.Intensity ratio method is used for the quantitative analysis shows various elements in abundance with calcium and silicon in majority.展开更多
有一般公式 Ni <SUB>1−x</SUB 的铁酸盐 > Zn <SUB > x </SUB > Fe <SUB>2</SUB > 有 x = 的 O <SUB>4</SUB> 0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6,和 0.7 被湿化学...有一般公式 Ni <SUB>1−x</SUB 的铁酸盐 > Zn <SUB > x </SUB > Fe <SUB>2</SUB > 有 x = 的 O <SUB>4</SUB> 0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6,和 0.7 被湿化学一起沉淀准备方法。结构并且磁性借助于 X 光检查衍射,磁化,和交流危险性大小被学习。X 光检查分析证实了样品的单相的形成。从 XRD 数据获得的格子参数被发现与 Zn 内容 x 增加。阳离子分发被 X 光检查紧张比率计算学习。磁化结果展出在同一直线上的含铁为 x ≤
的磁性的结构0.4,并且哪个的变化为 x】0.4 非在同一直线上。居里温度 T <SUB > 从交流危险性数据获得的 C </SUB> 与增加 x 减少。展开更多
Considering the cosmological constantΛas a thermodynamic pressure and its conjugate quantity as a thermodynamic volume as proposed by Kubiznak and Mann[J.High Energy Phys.1207(2012)033],we discuss the critical behavi...Considering the cosmological constantΛas a thermodynamic pressure and its conjugate quantity as a thermodynamic volume as proposed by Kubiznak and Mann[J.High Energy Phys.1207(2012)033],we discuss the critical behavior of charged AdS black hole in arbitrary dimensions d.In particular,we present a comparative study in terms of the spacetime dimension d and the displacement of critical points controlling the transition between the small and the large black holes.Such behaviors vary nicely in terms of d.Our result shows that the equation of state for a charged Reissner–Nordstrom AdS black hole predicts an universal number given by(2d-5)/(4d-8).The three-dimensional solution is also discussed.展开更多
The amount of fat is a component that complicates the clinical evaluation and the differential diagnostic between benign and malign lesions in the breast MRI examinations. To overcome this problem, an effective erasin...The amount of fat is a component that complicates the clinical evaluation and the differential diagnostic between benign and malign lesions in the breast MRI examinations. To overcome this problem, an effective erasing of the fat signal over the images acquisition process, is essentials. This study aims to compare three fat suppression techniques (STIR, SPIR, SPAIR) in the MR images of the breast and to evaluate the best image quality regarding its clinical usefulness. To mimic breast women, a breast phantom was constructed. First the exterior contour and, in second time, its content which was selected based on 7 samples with different components. Finally it was undergone to a MRI breast protocol with the three different fat saturation techniques. The examinations were performed on a 1.5 T MRI system (Philips?). A group of 5 experts evaluated 9 sequences, 3 of each with fat suppression techniques, in which the frequency offset and TI (Inversion Time) were the variables changed. This qualitative image analysis was performed according 4 parameters (saturation uniformity, saturation efficacy, detail of the anatomical structures and differentiation between the fibroglandular and adipose tissue), using a five-point Likert scale. The statistics analysis showed that anyone of the fat suppression techniques demonstrated significant differences compared to the others with (p > 0.05) and regarding each parameter independently. By Fleiss’ kappa coefficient there was a good agreement among observers P(e) = 0.68. When comparing STIR, SPIR and SPAIR techniques it was confirmed that all of them have advantages in the study of the breast MRI. For the studied parameters, the results through the Friedman Test showed that there are similar advantages applying anyone of these techniques.展开更多
Objectives: This research work intends to clarify the role of artificial saliva, in particularly the role of mucin, a salivary protein, on the surface properties and adhesion ability of Candida spp. oral clinical isol...Objectives: This research work intends to clarify the role of artificial saliva, in particularly the role of mucin, a salivary protein, on the surface properties and adhesion ability of Candida spp. oral clinical isolates to abiotic surfaces. Methods: Four oral clinical isolates of Candida spp. were used: two Candida albicans strains (AC;AM) and two Candida parapsilosis strains (AD;AM2). The strains were isolated from patients using oral prosthesis. The microorganisms were cultured in the absence or presence of mucin and artificial saliva, and their adhesion to an abiotic surface (coated with mucin and artificial saliva) was evaluated. Results: The presence of mucin per se onto the abiotic surface decreased the adhesion of all strains, although the combination of mucin with artificial saliva had reduced this effect. No direct correlation between adhesion and the surface free energies of adhesion of the microorganisms was found. Significance: Candida spp. were human commensal microorganisms that became pathogenic when the host immune defenses were compromised. Medical devices were colonized by Candida spp. particularly, oral prostheses, which might lead to the degradation of the prostheses and systemic infections. The salivary secretions that constantly cover the oral cavity influenced Candida spp. adhesion process. Therefore, it was important to understand the interactions between Candida spp., salivary proteins and the characteristic of oral prosthesis when developing materials for oral prostheses.展开更多
We propose an adaptive stencil construction for high-order accurate finite volume schemes a posteriori stabilized devoted to solve one-dimensional steady-state hyperbolic equations.High accuracy(up to the sixth-order ...We propose an adaptive stencil construction for high-order accurate finite volume schemes a posteriori stabilized devoted to solve one-dimensional steady-state hyperbolic equations.High accuracy(up to the sixth-order presently)is achieved,thanks to polynomial recon-structions while stability is provided with an a posteriori MOOD method which controls the cell polynomial degree for eliminating non-physical oscillations in the vicinity of dis-continuities.We supplemented this scheme with a stencil construction allowing to reduce even further the numerical dissipation.The stencil is shifted away from troubles(shocks,discontinuities,etc.)leading to less oscillating polynomial reconstructions.Experimented on linear,Burgers',and Euler equations,we demonstrate that the adaptive stencil technique manages to retrieve smooth solutions with optimal order of accuracy but also irregular ones without spurious oscillations.Moreover,we numerically show that the approach allows to reduce the dissipation still maintaining the essentially non-oscillatory behavior.展开更多
Coupling together the ferroelectric,pyroelectric,and photovoltaic characteristics within a single material is a novel way to improve the performance of photodetectors.In this work,we take advantage of the triple multi...Coupling together the ferroelectric,pyroelectric,and photovoltaic characteristics within a single material is a novel way to improve the performance of photodetectors.In this work,we take advantage of the triple multifunctionality shown by 0.5Ba(Zr_(0.2)Ti_(0.8))O_(3)-0.5(Ba_(0.7)Ca_(0.3))TiO_(3)(BCZT),as demonstrated in an Al/Si/SiOx/BCZT/ITO thin-film device.The Si/SiOx acts as an n-type layer to form a metal-ferroelectric-insulator-semiconductor heterostructure with the BCZT,and with Al and ITO as electrodes.The photo-response of the device,with excitation from a violet laser(405 nm wavelength),is carefully investigated,and it is shown that the photodetector performance is invariant with the chopper frequency owing to the pyro-phototronic effect,which corresponds to the coupling together of the pyroelectric and photovoltaic responses.However,the photodetector performance was significantly better than that of the devices operating based only on the pyro-phototronic effect by a factor of 4,due to the presence of ferroelectricity in the system.Thus,after a poling voltage of−15 V,for a laser power density of 230mW/cm^(2)and at a chopper frequency of 400Hz,optimized responsivity,detectivity,and sensitivity values of 13.1mA/W,1.7×10^(10)Jones,and 26.9,respectively,are achieved.Furthermore,ultrafast rise and fall times of 2.4 and 1.5μs,respectively,are obtained,which are 35,000 and 36,000 times faster rise and fall responses,respectively,than previous reports of devices with the ferro-pyro-phototronic effect.This is understood based on the much faster ferroelectric switching in ferroelectric thin films owing to the predominant 180°domains in a single direction out of plane.展开更多
Curcumin is a natural polyphenol with anti-oxidative, anti-inflammatory and anti-cancer properties. Its therapeutic potential is substantially hindered by the rather low water solubility and bioavailability, hence the...Curcumin is a natural polyphenol with anti-oxidative, anti-inflammatory and anti-cancer properties. Its therapeutic potential is substantially hindered by the rather low water solubility and bioavailability, hence the need for suitable carriers. In this study, we show that self-assembled nanogels obtained from hydrophobically modified dextrin are effective curcumin nanocarriers. The stability and loading efficiency of curcumin-loaded nanogel depends on the nanogel/curcumin ratio. Higher stability of the formulation is achieved in water than in PBS buffer, as evaluated by dynamic light scattering and fluorescence measurements. The in vitro release profile, using sink conditions, indicates that dextrin nanogel may perform as a suitable carrier for the controlled release of curcumin. Biological activity of curcumin-loaded nanogel in HeLa cell cultures was assessed using the MTS assay.展开更多
In the context of type-IIA orientifold compactifications,we discuss the fermion masses in a two-singlet-extended minimal-supersymmetric-standard-model four-stack quiver with U(3)×Sp(1)×U(1)×U(1)gauge sy...In the context of type-IIA orientifold compactifications,we discuss the fermion masses in a two-singlet-extended minimal-supersymmetric-standard-model four-stack quiver with U(3)×Sp(1)×U(1)×U(1)gauge symmetry.The corresponding effective superpotential exhibits hierarchical coupling term scales giving a partial solution to the fermion masses problem.Using the known data with upper bound neutrino masses mvt≤2 eV,we estimate the relevant scales for the model.展开更多
Bismuth ferrite(BFO)nanostructures and thin films have gained attraction as suitable candidates for energy storage and energy conversion due to their high energy storage efficiency,temperature stability and low dielec...Bismuth ferrite(BFO)nanostructures and thin films have gained attraction as suitable candidates for energy storage and energy conversion due to their high energy storage efficiency,temperature stability and low dielectric loss.Electrical properties of such multiferroic materials are tailored by ferroelectric and ferromagnetic constituents and have opened up amazing avenues in elec-trochemical supercapacitor and photovoltaic applications.Dopants play a significant role in optimizing the magnetic and dielec-tric properties of such materials owing to suitable applications.This review highlights the scientific advancements reported in BFO nanostructures for energy applications by optimizing their magnetic and dielectric properties.This paper starts with a brief introduction of BFO and a discussion on the effects of various dopants by different synthesis techniques,and their effects on the magnetic and dielectric properties are also portrayed.Eventually,this review summarizes the various doping effects,which paves way for future research on this multiferroic material.展开更多
The electronic and magnetic properties of the zinc-blende aluminum nitride doped with V and Cr are studied using the density functional theory(DFT),namely the KKR-CPA-PBE method.Pure Al N is found to be a wide band ga...The electronic and magnetic properties of the zinc-blende aluminum nitride doped with V and Cr are studied using the density functional theory(DFT),namely the KKR-CPA-PBE method.Pure Al N is found to be a wide band gap semiconductor,and doping V and Cr single impurities generate ferromagnetic half-metallic behavior.Moreover,the values of the formation energy reveal that these compounds are stable systems for all dopant concentrations.A self-consistent energy minimization scheme determines the ferromagnetic state as the stable magnetic state for V-and Cr-doping Al N.A double exchange mechanism is identified as the mechanism responsible for magnetism in our systems.When increasing doping impurities,the total magnetic moments increase linearly and the Curie temperature TC,calculated using the mean-field approximation,shows a significant change.The present findings reveal Cr-and V-doped zincblende Al N as potential candidates for high Curie temperature ferromagnetic materials.展开更多
In this paper,Carbon-doped Zinc Oxide(C-ZnO)samples were prepared using the solid-state reaction method.The influence of carbon-doping on the structural and dielectric properties of ZnO samples was studied.The shift i...In this paper,Carbon-doped Zinc Oxide(C-ZnO)samples were prepared using the solid-state reaction method.The influence of carbon-doping on the structural and dielectric properties of ZnO samples was studied.The shift in the highest peak position(101)in XRD patterns of carbon-doped samples was observed.The Raman peak at 581 cm^(-1) in undoped ZnO was shifted and broadened in carbon-doped ZnO samples.The ZnO samples doped with carbon show higher values of dielectric constant(~2400 at 1 kHz)compared to pure ZnO(~9 at 1 kHz)which was due to increase in native point defects in the samples.The ac conductivity(σ_(ac))value of the carbon-doped sample was enhanced by 103 times for((ZnO)_(0.9) C_(0.1))sample.展开更多
基金funding from CNPq(Brazilian council for scientific and technological development)through 201465/2015-9 scholarship of the“Science without borders”programsupport of MCTES/FCT(Portuguese Science and Technology Foundation of Portuguese Ministry of Science and Technology)through CEECIND/04583/2017 grant+1 种基金financially supported by:Base Funding-UIDB/04708/2020 of the CONSTRUCT-Instituto de I&D em Estruturas e Construções-funded by national funds through FCT/MCTES(PIDDAC)A special acknowledgment is also due to the Portuguese National Steel Industry of Maia,part of MEGASA group,for the steel slag supply and to Professor Joaquim Faria for his support in understanding the basic notions of chemistry.
文摘In this work,an alternative alkali-activated cement(AAC)made of ladle slag precursor mixed with sodium hydroxide and sodium silicate has been developed to enhance the bearing capacity of estuarine soils in coastal conditions via deep soil mixing(DSM).The AAC was optimized to use a low reactivity precursor(ladle slag)and to deal with a contaminated high-water content natural sediment cured under water.The material performance was analysed by comparison to a mixture made with Portland cement and cured in the same conditions.Flexural and unconfined compressive strength tests as well as seismic waves measurements after 3-,7-,14-and 28-d curing were performed to obtain a relationship between elastic stiffness and strength with curing time for both mixtures.Remarkably,the AAC mix demonstrated superior strength results,exhibiting almost double flexural and compressive strengths after 28 d compared to the Portland cement mix.The AAC mix also showed a higher rate of stiffness increase than the Portland cement mix,which has a higher initial stiffness at young ages but lower stiffness evolution.Leachate analysis confirmed that the proposed AAC could effectively immobilise any contaminants from soil or precursors.The effect of curing under stress was analysed in triaxial compression tests and found to be insignificant,indicating that laboratory data obtained without stress curing can represent the material's behaviour in a DSM column,which will cure under the weight of the column.
文摘Laser Induced Breakdown Spectroscopic(LIBS)technique was used to detect calcium and silicon in an unknown sample.In this method plasma was generated by Nd∶YAG laser of wavelength 1 064 nm with energy 400 mJ and pulse duration between 5~10ns.The method was applied for the qualitative as well as quantitative analysis.In the qualitative analysis,the electron number density(Ne)of plasma containing calcium and silicon is determined showing that Neof neutral particles is equivalent to 1016(cm-3)whereas for ionized particles it is 1017(cm-3).Plasma temperature is measured using Boltzmann plot method which must be greater than 10 000 k.Intensity ratio method is used for the quantitative analysis shows various elements in abundance with calcium and silicon in majority.
文摘有一般公式 Ni <SUB>1−x</SUB 的铁酸盐 > Zn <SUB > x </SUB > Fe <SUB>2</SUB > 有 x = 的 O <SUB>4</SUB> 0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6,和 0.7 被湿化学一起沉淀准备方法。结构并且磁性借助于 X 光检查衍射,磁化,和交流危险性大小被学习。X 光检查分析证实了样品的单相的形成。从 XRD 数据获得的格子参数被发现与 Zn 内容 x 增加。阳离子分发被 X 光检查紧张比率计算学习。磁化结果展出在同一直线上的含铁为 x ≤
的磁性的结构0.4,并且哪个的变化为 x】0.4 非在同一直线上。居里温度 T <SUB > 从交流危险性数据获得的 C </SUB> 与增加 x 减少。
文摘Considering the cosmological constantΛas a thermodynamic pressure and its conjugate quantity as a thermodynamic volume as proposed by Kubiznak and Mann[J.High Energy Phys.1207(2012)033],we discuss the critical behavior of charged AdS black hole in arbitrary dimensions d.In particular,we present a comparative study in terms of the spacetime dimension d and the displacement of critical points controlling the transition between the small and the large black holes.Such behaviors vary nicely in terms of d.Our result shows that the equation of state for a charged Reissner–Nordstrom AdS black hole predicts an universal number given by(2d-5)/(4d-8).The three-dimensional solution is also discussed.
文摘The amount of fat is a component that complicates the clinical evaluation and the differential diagnostic between benign and malign lesions in the breast MRI examinations. To overcome this problem, an effective erasing of the fat signal over the images acquisition process, is essentials. This study aims to compare three fat suppression techniques (STIR, SPIR, SPAIR) in the MR images of the breast and to evaluate the best image quality regarding its clinical usefulness. To mimic breast women, a breast phantom was constructed. First the exterior contour and, in second time, its content which was selected based on 7 samples with different components. Finally it was undergone to a MRI breast protocol with the three different fat saturation techniques. The examinations were performed on a 1.5 T MRI system (Philips?). A group of 5 experts evaluated 9 sequences, 3 of each with fat suppression techniques, in which the frequency offset and TI (Inversion Time) were the variables changed. This qualitative image analysis was performed according 4 parameters (saturation uniformity, saturation efficacy, detail of the anatomical structures and differentiation between the fibroglandular and adipose tissue), using a five-point Likert scale. The statistics analysis showed that anyone of the fat suppression techniques demonstrated significant differences compared to the others with (p > 0.05) and regarding each parameter independently. By Fleiss’ kappa coefficient there was a good agreement among observers P(e) = 0.68. When comparing STIR, SPIR and SPAIR techniques it was confirmed that all of them have advantages in the study of the breast MRI. For the studied parameters, the results through the Friedman Test showed that there are similar advantages applying anyone of these techniques.
文摘Objectives: This research work intends to clarify the role of artificial saliva, in particularly the role of mucin, a salivary protein, on the surface properties and adhesion ability of Candida spp. oral clinical isolates to abiotic surfaces. Methods: Four oral clinical isolates of Candida spp. were used: two Candida albicans strains (AC;AM) and two Candida parapsilosis strains (AD;AM2). The strains were isolated from patients using oral prosthesis. The microorganisms were cultured in the absence or presence of mucin and artificial saliva, and their adhesion to an abiotic surface (coated with mucin and artificial saliva) was evaluated. Results: The presence of mucin per se onto the abiotic surface decreased the adhesion of all strains, although the combination of mucin with artificial saliva had reduced this effect. No direct correlation between adhesion and the surface free energies of adhesion of the microorganisms was found. Significance: Candida spp. were human commensal microorganisms that became pathogenic when the host immune defenses were compromised. Medical devices were colonized by Candida spp. particularly, oral prostheses, which might lead to the degradation of the prostheses and systemic infections. The salivary secretions that constantly cover the oral cavity influenced Candida spp. adhesion process. Therefore, it was important to understand the interactions between Candida spp., salivary proteins and the characteristic of oral prosthesis when developing materials for oral prostheses.
基金support by FEDER-Fundo Europeu de Desenvolvimento Regional,through COMPETE 2020-Programa Operational Fatores de Competitividade,and the National Funds through FCT-Fundacao para a Ciencia e a Tecnologia,project no.UID/FIS/04650/2019support by FEDER-Fundo Europeu de Desenvolvimento Regional,through COMPETI E 2020-Programa Operacional Fatores de Competitividade,and the National Funds through FCT-Fundacao para a Ciencia e a Tecnologia,project no.POCI-01-0145-FEDER-028118
文摘We propose an adaptive stencil construction for high-order accurate finite volume schemes a posteriori stabilized devoted to solve one-dimensional steady-state hyperbolic equations.High accuracy(up to the sixth-order presently)is achieved,thanks to polynomial recon-structions while stability is provided with an a posteriori MOOD method which controls the cell polynomial degree for eliminating non-physical oscillations in the vicinity of dis-continuities.We supplemented this scheme with a stencil construction allowing to reduce even further the numerical dissipation.The stencil is shifted away from troubles(shocks,discontinuities,etc.)leading to less oscillating polynomial reconstructions.Experimented on linear,Burgers',and Euler equations,we demonstrate that the adaptive stencil technique manages to retrieve smooth solutions with optimal order of accuracy but also irregular ones without spurious oscillations.Moreover,we numerically show that the approach allows to reduce the dissipation still maintaining the essentially non-oscillatory behavior.
基金Royal Academy of Engineering,Grant/Award Number:RF\201718\1701ERC grant,Grant/Award Number:EU-H2020-ERC-ADG#882929+3 种基金Portuguese Foundation for Science and Technology,Grant/Award Number:UIDB/04650/2020Royal Academy of Engineering Chair in Emerging Technologies,Grant/Award Number:CIET1819_24European Union's Horizon 2020 research and innovation programme,Grant/Award Number:958174EPSRC CAM-IES,Grant/Award Number:EP/P007767/。
文摘Coupling together the ferroelectric,pyroelectric,and photovoltaic characteristics within a single material is a novel way to improve the performance of photodetectors.In this work,we take advantage of the triple multifunctionality shown by 0.5Ba(Zr_(0.2)Ti_(0.8))O_(3)-0.5(Ba_(0.7)Ca_(0.3))TiO_(3)(BCZT),as demonstrated in an Al/Si/SiOx/BCZT/ITO thin-film device.The Si/SiOx acts as an n-type layer to form a metal-ferroelectric-insulator-semiconductor heterostructure with the BCZT,and with Al and ITO as electrodes.The photo-response of the device,with excitation from a violet laser(405 nm wavelength),is carefully investigated,and it is shown that the photodetector performance is invariant with the chopper frequency owing to the pyro-phototronic effect,which corresponds to the coupling together of the pyroelectric and photovoltaic responses.However,the photodetector performance was significantly better than that of the devices operating based only on the pyro-phototronic effect by a factor of 4,due to the presence of ferroelectricity in the system.Thus,after a poling voltage of−15 V,for a laser power density of 230mW/cm^(2)and at a chopper frequency of 400Hz,optimized responsivity,detectivity,and sensitivity values of 13.1mA/W,1.7×10^(10)Jones,and 26.9,respectively,are achieved.Furthermore,ultrafast rise and fall times of 2.4 and 1.5μs,respectively,are obtained,which are 35,000 and 36,000 times faster rise and fall responses,respectively,than previous reports of devices with the ferro-pyro-phototronic effect.This is understood based on the much faster ferroelectric switching in ferroelectric thin films owing to the predominant 180°domains in a single direction out of plane.
基金This research was supported by Fundacao para a Ciencia e a Tecnologia under grant SFRH/BD/22242/2005.
文摘Curcumin is a natural polyphenol with anti-oxidative, anti-inflammatory and anti-cancer properties. Its therapeutic potential is substantially hindered by the rather low water solubility and bioavailability, hence the need for suitable carriers. In this study, we show that self-assembled nanogels obtained from hydrophobically modified dextrin are effective curcumin nanocarriers. The stability and loading efficiency of curcumin-loaded nanogel depends on the nanogel/curcumin ratio. Higher stability of the formulation is achieved in water than in PBS buffer, as evaluated by dynamic light scattering and fluorescence measurements. The in vitro release profile, using sink conditions, indicates that dextrin nanogel may perform as a suitable carrier for the controlled release of curcumin. Biological activity of curcumin-loaded nanogel in HeLa cell cultures was assessed using the MTS assay.
文摘In the context of type-IIA orientifold compactifications,we discuss the fermion masses in a two-singlet-extended minimal-supersymmetric-standard-model four-stack quiver with U(3)×Sp(1)×U(1)×U(1)gauge symmetry.The corresponding effective superpotential exhibits hierarchical coupling term scales giving a partial solution to the fermion masses problem.Using the known data with upper bound neutrino masses mvt≤2 eV,we estimate the relevant scales for the model.
文摘Bismuth ferrite(BFO)nanostructures and thin films have gained attraction as suitable candidates for energy storage and energy conversion due to their high energy storage efficiency,temperature stability and low dielectric loss.Electrical properties of such multiferroic materials are tailored by ferroelectric and ferromagnetic constituents and have opened up amazing avenues in elec-trochemical supercapacitor and photovoltaic applications.Dopants play a significant role in optimizing the magnetic and dielec-tric properties of such materials owing to suitable applications.This review highlights the scientific advancements reported in BFO nanostructures for energy applications by optimizing their magnetic and dielectric properties.This paper starts with a brief introduction of BFO and a discussion on the effects of various dopants by different synthesis techniques,and their effects on the magnetic and dielectric properties are also portrayed.Eventually,this review summarizes the various doping effects,which paves way for future research on this multiferroic material.
基金the Académie Hassan II des Sciences et Techniques,Morocco,for its financial support。
文摘The electronic and magnetic properties of the zinc-blende aluminum nitride doped with V and Cr are studied using the density functional theory(DFT),namely the KKR-CPA-PBE method.Pure Al N is found to be a wide band gap semiconductor,and doping V and Cr single impurities generate ferromagnetic half-metallic behavior.Moreover,the values of the formation energy reveal that these compounds are stable systems for all dopant concentrations.A self-consistent energy minimization scheme determines the ferromagnetic state as the stable magnetic state for V-and Cr-doping Al N.A double exchange mechanism is identified as the mechanism responsible for magnetism in our systems.When increasing doping impurities,the total magnetic moments increase linearly and the Curie temperature TC,calculated using the mean-field approximation,shows a significant change.The present findings reveal Cr-and V-doped zincblende Al N as potential candidates for high Curie temperature ferromagnetic materials.
基金The author(MD.Parvez Ahmad)thanks the Department of Science&Technology(DST),Government of India,for the award of DST-FIST level-1(SR/FST/PS-1/2018/35)scheme to Department of Physics,KLEF.
文摘In this paper,Carbon-doped Zinc Oxide(C-ZnO)samples were prepared using the solid-state reaction method.The influence of carbon-doping on the structural and dielectric properties of ZnO samples was studied.The shift in the highest peak position(101)in XRD patterns of carbon-doped samples was observed.The Raman peak at 581 cm^(-1) in undoped ZnO was shifted and broadened in carbon-doped ZnO samples.The ZnO samples doped with carbon show higher values of dielectric constant(~2400 at 1 kHz)compared to pure ZnO(~9 at 1 kHz)which was due to increase in native point defects in the samples.The ac conductivity(σ_(ac))value of the carbon-doped sample was enhanced by 103 times for((ZnO)_(0.9) C_(0.1))sample.