In this paper, Finite Difference Time Domain (FDTD) is utilized to simulate metamaterials of Double Negative (DNG) origin that refers to those materials having simultaneous negative permittivity and permeability. The ...In this paper, Finite Difference Time Domain (FDTD) is utilized to simulate metamaterials of Double Negative (DNG) origin that refers to those materials having simultaneous negative permittivity and permeability. The problem regarding space formulation is achieved by means of auxiliary differential equation method (ADE), which is easy, reliable and also causal process in nature thus making it proficient. It uses fair approximations to explicate the model. Mur’s boundary condition is used for 1-D problem space and convolution perfectly matched layer boundary is implemented for 2-D problem space. The properties of metamaterial conform their speculations of energy absorption, enhancement and backward propagation property with the aid of graphs engineered by Matlab simulation both in 1-D and 2-D. Also, the interaction of fields on DNG and Double Positive (DPS) layers is contrasted. The results achieved elucidate the validity and effectiveness of the ADE method and the Convolution Perfectly Match Layer (CPML) in designing DNG metamaterials.展开更多
The synergistic effects of 2′-Fucosyllactose(2′-FL)or galactooligosaccharide(GOS)with Bifidobacterium bifidum DNG6(DNG6)attenuating dextran sulfate sodium(DSS)-induced colitis in mice were investigated.The results s...The synergistic effects of 2′-Fucosyllactose(2′-FL)or galactooligosaccharide(GOS)with Bifidobacterium bifidum DNG6(DNG6)attenuating dextran sulfate sodium(DSS)-induced colitis in mice were investigated.The results showed that DNG6,2′-FL and GOS alone or in combination could effectively prevent and improve symptoms of colitis.Among them,2′-FL and DNG6(2′-FL-DNG6)demonstrated the best synergistic effect.2′-FL-DNG6 significantly increased the abundance and diversity of gut microbiota,and boosted beneficial bacteria(such as Bifidobacterium,Lactobacillus,and Akkermansia)abundances(p<0.05).Additionally,2′-FL-DNG6 significantly upregulated Claudin-1,Occludin,and ZO-1 proteins and mRNA expressions,and inhibited TLR4/NF-κB in-flammatory pathway-related proteins and mRNA expressions(p<0.05).Moreover,it significantly reduced the release of TNF-α,IL-1β,IL-6,and myeloperoxidase,while significantly increased levels of IL-10 and short-chain fatty acids(SCFAs)(p<0.05).In conclusion,the combination of 2′-FL and DNG6 could ameliorate intestinal barrier damage and reduce inflammatory response through the SCFAs-TLR4/NF-κB cascade response.These may provide new insights into the different effects of specific Bifidobacteria on improving colitis under different ol-igosaccharides and scientific bases to develop the most effective Bifidobacteria-HMOs combinations for more precise and targeted gut health interventions.展开更多
This paper presents a textile-based C-shaped split-ring resonators(SRR)metamaterial(MTM)unit cells with an electrical tunability function.The proposed MTM was composed of two symmetrical C-shaped SRR combined with a c...This paper presents a textile-based C-shaped split-ring resonators(SRR)metamaterial(MTM)unit cells with an electrical tunability function.The proposed MTM was composed of two symmetrical C-shaped SRR combined with a central diagonal metal bar,whereas the RF varactor diode is placed on the backside of the splitted ground plane.Stopband behavior of single and array MTM unit cells were analyzed while the achieved negative index physical characteristics were widely studies.Though four different MTM arrays(i.e.,1×1,1×2,2×1,and 2×2)were analyzed in simulation,a 2×2-unit cell array was chosen to fabricate,and it was further undergone experimental validation.This proposed tunable MTM exhibits double negative(DNG)/left-handed properties with an average bandwidth of more than 2.8 GHz.Furthermore,attainable negative permittivity and negative permeability are within 2.66 to 9.59 GHz and within 2.77 to 15 GHz,respectively,at the frequency of interest(between 1 and 15 GHz).Moreover,the proposed tunable MTM also showed tunable transmission coefficient characteristics.The proposed electrically tunable textile MTM might function in a dynamic mode,making it suitable for a variety of microwave-wearable applications.A satisfactory agreement between simulations and experiments were achieved,demonstrating that the proposed MTM can operate over a wide bandwidth.展开更多
This study proposed a new royal crown-shaped polarisation insensitive double negative triple band microwave range electromagnetic metamaterial absorber(MA).The primary purpose of this study is to utilise the exotic ch...This study proposed a new royal crown-shaped polarisation insensitive double negative triple band microwave range electromagnetic metamaterial absorber(MA).The primary purpose of this study is to utilise the exotic characteristics of this perfect metamaterial absorber(PMA)for microwave wireless communications.The fundamental unit cell of the proposed MA consists of two pentagonal-shaped resonators and two inverse C-shaped metallic components surrounded by a split ring resonator(SRR).The bottom thin copper deposit and upper metallic resonator surface are disjoined by an FR-4 dielectric substrate with 1.6 mm thickness.The CST MW studio,a high-frequency electromagnetic simulator has been deployed for numerical simula-tion of the unit cell in the frequency range of 4 to 14 GHz.In the TE mode,the offered MA structure demonstrated three different absorption peaks at 6.85 GHz(C-band),8.87 GHz(X-band),and 12.03 GHz(Ku-band),with 96.82%,99.24%,and 99.43%absorptivity,respectively.The electric field,magnetic field,and surface current distribution were analysed using Maxwell’s-Curl equations,whereas the angle sensitivity was investigated to comprehend the absorption mechanism of the proposed absorber.The numerical results were verified using the Ansys HFSS(high-frequency structure simulator)and ADS(advanced design system)for equivalent circuit models.Moreover,the proposed MA is polarisation and incident angle independent.Hence,the application of this MA can be extended to a great extent,including airborne radar applications,defence,and stealth-coating technology.展开更多
文摘In this paper, Finite Difference Time Domain (FDTD) is utilized to simulate metamaterials of Double Negative (DNG) origin that refers to those materials having simultaneous negative permittivity and permeability. The problem regarding space formulation is achieved by means of auxiliary differential equation method (ADE), which is easy, reliable and also causal process in nature thus making it proficient. It uses fair approximations to explicate the model. Mur’s boundary condition is used for 1-D problem space and convolution perfectly matched layer boundary is implemented for 2-D problem space. The properties of metamaterial conform their speculations of energy absorption, enhancement and backward propagation property with the aid of graphs engineered by Matlab simulation both in 1-D and 2-D. Also, the interaction of fields on DNG and Double Positive (DPS) layers is contrasted. The results achieved elucidate the validity and effectiveness of the ADE method and the Convolution Perfectly Match Layer (CPML) in designing DNG metamaterials.
基金supported by the National Natural Science Foundation of China(32302043)China Postdoctoral Science Foundation(2024M750385)+2 种基金Natural Science Foundation of Heilongjiang Province(LH2023C112)Key Project of Natural Science Foundation of Heilongjiang Province(ZD2022C007)Foundation of National Center of Technology Innovation for Dairy(2022-KFKT-12).
文摘The synergistic effects of 2′-Fucosyllactose(2′-FL)or galactooligosaccharide(GOS)with Bifidobacterium bifidum DNG6(DNG6)attenuating dextran sulfate sodium(DSS)-induced colitis in mice were investigated.The results showed that DNG6,2′-FL and GOS alone or in combination could effectively prevent and improve symptoms of colitis.Among them,2′-FL and DNG6(2′-FL-DNG6)demonstrated the best synergistic effect.2′-FL-DNG6 significantly increased the abundance and diversity of gut microbiota,and boosted beneficial bacteria(such as Bifidobacterium,Lactobacillus,and Akkermansia)abundances(p<0.05).Additionally,2′-FL-DNG6 significantly upregulated Claudin-1,Occludin,and ZO-1 proteins and mRNA expressions,and inhibited TLR4/NF-κB in-flammatory pathway-related proteins and mRNA expressions(p<0.05).Moreover,it significantly reduced the release of TNF-α,IL-1β,IL-6,and myeloperoxidase,while significantly increased levels of IL-10 and short-chain fatty acids(SCFAs)(p<0.05).In conclusion,the combination of 2′-FL and DNG6 could ameliorate intestinal barrier damage and reduce inflammatory response through the SCFAs-TLR4/NF-κB cascade response.These may provide new insights into the different effects of specific Bifidobacteria on improving colitis under different ol-igosaccharides and scientific bases to develop the most effective Bifidobacteria-HMOs combinations for more precise and targeted gut health interventions.
基金This work is supported by the Universiti Kebangsaan Malaysia Research Grant under Grant Number.GUP-2020-017.
文摘This paper presents a textile-based C-shaped split-ring resonators(SRR)metamaterial(MTM)unit cells with an electrical tunability function.The proposed MTM was composed of two symmetrical C-shaped SRR combined with a central diagonal metal bar,whereas the RF varactor diode is placed on the backside of the splitted ground plane.Stopband behavior of single and array MTM unit cells were analyzed while the achieved negative index physical characteristics were widely studies.Though four different MTM arrays(i.e.,1×1,1×2,2×1,and 2×2)were analyzed in simulation,a 2×2-unit cell array was chosen to fabricate,and it was further undergone experimental validation.This proposed tunable MTM exhibits double negative(DNG)/left-handed properties with an average bandwidth of more than 2.8 GHz.Furthermore,attainable negative permittivity and negative permeability are within 2.66 to 9.59 GHz and within 2.77 to 15 GHz,respectively,at the frequency of interest(between 1 and 15 GHz).Moreover,the proposed tunable MTM also showed tunable transmission coefficient characteristics.The proposed electrically tunable textile MTM might function in a dynamic mode,making it suitable for a variety of microwave-wearable applications.A satisfactory agreement between simulations and experiments were achieved,demonstrating that the proposed MTM can operate over a wide bandwidth.
基金supported by Fundamental Research Grant Scheme(FRGS),MOE,Malaysia,Code:FRGS/1/2022/TK07/UKM/02/22.
文摘This study proposed a new royal crown-shaped polarisation insensitive double negative triple band microwave range electromagnetic metamaterial absorber(MA).The primary purpose of this study is to utilise the exotic characteristics of this perfect metamaterial absorber(PMA)for microwave wireless communications.The fundamental unit cell of the proposed MA consists of two pentagonal-shaped resonators and two inverse C-shaped metallic components surrounded by a split ring resonator(SRR).The bottom thin copper deposit and upper metallic resonator surface are disjoined by an FR-4 dielectric substrate with 1.6 mm thickness.The CST MW studio,a high-frequency electromagnetic simulator has been deployed for numerical simula-tion of the unit cell in the frequency range of 4 to 14 GHz.In the TE mode,the offered MA structure demonstrated three different absorption peaks at 6.85 GHz(C-band),8.87 GHz(X-band),and 12.03 GHz(Ku-band),with 96.82%,99.24%,and 99.43%absorptivity,respectively.The electric field,magnetic field,and surface current distribution were analysed using Maxwell’s-Curl equations,whereas the angle sensitivity was investigated to comprehend the absorption mechanism of the proposed absorber.The numerical results were verified using the Ansys HFSS(high-frequency structure simulator)and ADS(advanced design system)for equivalent circuit models.Moreover,the proposed MA is polarisation and incident angle independent.Hence,the application of this MA can be extended to a great extent,including airborne radar applications,defence,and stealth-coating technology.
