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1.
Public Health Nutr ; 27(1): e122, 2024 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-38533778

RESUMO

OBJECTIVE: We aimed to examine the association between dietary Se intake and CVD risk in Chinese adults. DESIGN: This prospective cohort study included adults above 20 years old in the China Health and Nutrition Survey (CHNS), and they were followed up from 1997 to 2015 (n 16 030). Dietary data were retrieved from CHNS, and a 3-d, 24-h recall of food intake was used to assess the cumulative average intake of dietary Se, which was divided into quartiles. The Cox proportional hazards model was adopted to analyse the association between dietary Se intake and incident CVD risk. SETTING: CHNS (1991, 1993, 1997, 2000, 2004, 2006, 2009, 2011 and 2015). RESULTS: A total of 663 respondents developed CVD after being followed up for a mean of 9·9 years (median 9 years). The incidence of CVD was 4·3, 3·7, 4·6 and 4·0 per 1000 person-years across the quartiles of cumulative Se intake. After adjusting all potential factors, no significant associations were found between cumulative Se intake and CVD risk. No interactions were found between Se intake and income, urbanisation, sex, region, weight, hypertension and CVD risk. CONCLUSION: We found no association between dietary Se and CVD.


Assuntos
Doenças Cardiovasculares , Dieta , Inquéritos Nutricionais , Selênio , Humanos , China/epidemiologia , Masculino , Feminino , Doenças Cardiovasculares/epidemiologia , Doenças Cardiovasculares/prevenção & controle , Adulto , Pessoa de Meia-Idade , Selênio/administração & dosagem , Dieta/estatística & dados numéricos , Estudos Retrospectivos , Estudos Prospectivos , Incidência , Modelos de Riscos Proporcionais , Fatores de Risco , Adulto Jovem
2.
BMC Public Health ; 24(1): 155, 2024 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-38212718

RESUMO

BACKGROUND: Good food safety practices are essential to minimizing foodborne diseases. The present study explored the food safety-related practices of residents during the COVID-19 pandemic in Southwest China and identified the impacting factors. METHODS: Residents aged 18-75 years from Guizhou, Yunnan, Sichuan, and Chongqing, China, were included in our study. The convenience sampling method was used to select participants, and face-to-face surveys were conducted in households and communities to collect data. Descriptive statistics including sociodemographic characteristics of respondents and weighted percentages were obtained and the log-binomial regression was used to evaluate the influencing factors associated with food safety-related practices. RESULTS: Overall, 7,848 respondents were involved, with 97.5% efficacy. Disparities in food safety-related practices were observed between males and females, with the former performing poorer practices than the latter (70.5% vs. 68.0%, respectively). Notably, paying attention to nutrition labels when shopping for prepackaged foods was the worst practice. Age, ethnicity, region, occupation, education level, and income were identified as significant determinants of food safety-related practices. Moreover, in comparison to males, females were more likely to acquire pertinent knowledge from diverse sources, including social media, family members/ friends, books/ newspapers/ magazines, experts, and food sales staff (p < 0.05). CONCLUSIONS: Males performed inferior food safety-related practices than females during the COVID-19 pandemic in Southwest China. It is suggested that future food safety education programs should incorporate diverse targeted approaches, with emphasis on males. The role of mainstream media in promoting food safety practices should be expanded and prioritized in the forthcoming initiatives.


Assuntos
COVID-19 , Masculino , Feminino , Humanos , COVID-19/epidemiologia , COVID-19/prevenção & controle , Estudos Transversais , Pandemias/prevenção & controle , China/epidemiologia , Inocuidade dos Alimentos , Inquéritos e Questionários , Conhecimentos, Atitudes e Prática em Saúde
3.
BMC Public Health ; 23(1): 2550, 2023 12 21.
Artigo em Inglês | MEDLINE | ID: mdl-38129799

RESUMO

BACKGROUND: Unhealthy snacking behaviors and body weight misperception are both significant concerns in adolescent health. Weight misperception are common among youth and may influence their motivation to engage in health-related behaviors, however, the effect on snacking patterns choice remains unclear. Our study aimed to examine the relationship between body weight misperception and snacking pattern choice among school adolescents. METHODS: A cross-sectional study was conducted using an online survey platform. Body weight misperception was defined based on perceived body weight and true weight. Snack intake was measured using a qualitative food-frequency questionnaire. Factor analysis was used to identify snacking patterns, and multiple linear regression was employed to examine the association between body weight misperception and snacking patterns. RESULTS: 190,296 students with the average age of 13.3 ± 1.0 years was included, and 44.5% of students misperceived their weight. Overestimation was more prevalent than underestimation. Two snacking patterns, namely a high-calorie snacking pattern and a healthy snacking pattern, were identified with eigenvalues > 1. Weight underestimation was positively linked to high-calorie snacking pattern scores for both normal weight students (ß: 0.16, 95% CI: 0.11, 0.21) and students with overweight/obesity (ß: 0.44, 95% CI: 0.35, 0.52), and to healthy snacking scores for students with overweight/obesity (ß: 0.28, 95% CI: 0.22, 0.33), but negatively linked to healthy snacking pattern scores for normal weight students (ß: -0.12, 95% CI: -0.15, -0.09). Conversely, weight overestimation was negatively linked to both high-calorie and healthy snacking pattern scores for normal weight students (ß: -0.07, 95% CI: -0.11, -0.04 and ß: -0.13, 95% CI: -0.15, -0.10), but positively linked to healthy snacking scores for underweight students (ß: 0.15, 95% CI: 0.08, 0.21). Interactions were found between sex, grade, accommodation, only child, primary guardians, parental education level and weight misperception to snacking patterns. CONCLUSIONS: Adolescents with normal weight and overweight/obesity who misperceived their weight exhibited less healthy snacking patterns, whereas underweight students who misperceived their weight displayed healthier snacking patterns. Comprehensive programs are crucial to educate and guide adolescents in understanding their weight status and making healthier snack choices, involving families, schools, and society.


Assuntos
Imagem Corporal , Comportamento Alimentar , Obesidade , Sobrepeso , Magreza , Adolescente , Criança , Humanos , Índice de Massa Corporal , Peso Corporal , Estudos Transversais , Obesidade/epidemiologia , Sobrepeso/epidemiologia , Lanches
5.
Arch Public Health ; 81(1): 188, 2023 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-37872636

RESUMO

OBJECTIVE: The global epidemic of overweight/obesity in children and adolescents poses a significant public health threat. This longitudinal study aims to investigate the relationship between adolescents' and their parents' dietary knowledge and overweight/obesity among adolescents in China. METHODS: Data were collected from the China Health and Nutrition Survey (CHNS) in 2004, 2006, 2009, 2011 and 2015. Overweight/obesity was defined according to the International Obesity Task Force (IOTF) cut-off for body mass index (BMI). A set of questions were used to assess the dietary knowledge scores of both adolescents and their parents during face-to-face interviews. Mixed effect models were used to analyze the data. RESULTS: A total of 2035 adolescents aged 12-17 years were included in the data analysis. The mean BMI increased from 19.2 in 2004 to 20.5 in 2015, with a significant increase in the prevalence of overweight and obesity from 6.8% and 0.5% in 2004 to 15.1% and 7.8% in 2015, respectively. Adolescents with medium-score dietary knowledge were less likely to be overweight/obese compared to those with low-score dietary knowledge (OR (95% CI): 0.20 (0.05-0.80), P < 0.05). However, there was no association between parental dietary knowledge and adolescents' BMI or overweight/obesity (P > 0.05). Additionally, a significant interaction between adolescents' dietary knowledge score and education in relation to adolescents' BMI (P for interaction < 0.05). CONCLUSION: Adolescents with medium dietary knowledge were less likely to be overweight/obese than those with low knowledge, but no association was found with parental knowledge. Promoting nutritional education and healthy eating habits is vital to prevent overweight/obesity.

6.
PeerJ ; 11: e15932, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37692118

RESUMO

In the current study, we explored the relationship between melatonin and lactose synthesis in in vivo and in vitro conditions. We found that long-term melatonin feeding to the dairy cows significantly reduced the milk lactose content in a dose dependent manner. This lactose reduction was not associated with a negative energy balance, since melatonin treatment did not alter the fat, glucose, or protein metabolisms of the cows. To identify the potential molecular mechanisms, the cow's mammary epithelial cells were cultured for gene expression analysis. The results showed that the effect of melatonin on lactose reduction was mediated by its receptor MT1. MT1 activation downregulated the mRNA expression of the prolactin receptor gene (PRLR), which then suppressed the gene expression of SLC35B1. SLC35B1 is a galactose transporter and is responsible for the transportation of galactose to Golgi apparatus for lactose synthesis. Its suppression reduced the lactose synthesis and the milk lactose content. The discovery of this signal transduction pathway of melatonin on lactose synthesis provides a novel aspect of melatonin's effect on carbohydrate metabolism in cows and maybe also in other mammals, including humans.


Assuntos
Melatonina , Receptores da Prolactina , Animais , Bovinos , Feminino , Metabolismo dos Carboidratos , Galactose , Lactose , Melatonina/farmacologia , Receptores de Melatonina , Transdução de Sinais
7.
Microbiome ; 11(1): 196, 2023 08 29.
Artigo em Inglês | MEDLINE | ID: mdl-37644507

RESUMO

BACKGROUND: Methane (CH4) is a major greenhouse gas, and ruminants are one of the sources of CH4 which is produced by the rumen microbiota. Modification of the rumen microbiota compositions will impact the CH4 production. In this study, the effects of melatonin on methane production in cows were investigated both in the in vitro and in vivo studies. RESULTS: Melatonin treatment significantly reduced methane production in both studies. The cows treated with melatonin reduced methane emission from their respiration by approximately 50%. The potential mechanisms are multiple. First, melatonin lowers the volatile fatty acids (VFAs) production in rumen and reduces the raw material for CH4 synthesis. Second, melatonin not only reduces the abundance of Methanobacterium which are responsible for generating methane but also inhibits the populations of protozoa to break the symbiotic relationship between Methanobacterium and protozoa in rumen to further lowers the CH4 production. The reduced VFA production is not associated with food intake, and it seems also not to jeopardize the nutritional status of the cows. This was reflected by the increased milk lipid and protein contents in melatonin treated compared to the control cows. It is likely that the energy used to synthesize methane is saved to compensate the reduced VFA production. CONCLUSION: This study enlightens the potential mechanisms by which melatonin reduces rumen methane production in dairy cows. Considering the greenhouse effects of methane on global warming, these findings provide valuable information using different approaches to achieve low carbon dairy farming to reduce the methane emission. Video Abstract.


Assuntos
Melatonina , Feminino , Animais , Bovinos , Melatonina/farmacologia , Rúmen , Agricultura , Carbono , Metano
8.
Nutrients ; 15(2)2023 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-36678268

RESUMO

Inconsistent findings have been discovered in studies examining the link between dietary selenium (Se) and sleep. Data were obtained from 17,176 people aged 20 and over who participated in the China Health and Nutrition Survey (CHNS) from 2004 to 2011. Face-to-face interviews were used to measure sleep duration in 2004, 2006, 2009, and 2011. To track dietary Se consumption, a 3-day, 24-h recall was undertaken. In the analysis, multilevel mixed-effects logistic regression was employed. The odds ratios (95% confidence intervals) of optimal sleep duration (7-9 h/day) in the regression of Model 4 were 1.00, 1.01 (0.89-1.15) and 1.19 (1.02-1.38) for the three tertiles of selenium consumption, respectively. Only overweight patients displayed a substantial positive connection between Se intake and the optimal sleep duration in the subgroup analysis. In summary, Se intake was significantly associated with optimal sleep duration.


Assuntos
Selênio , Humanos , Adulto , Estudos Longitudinais , Dieta , Estado Nutricional , Sono , Inquéritos Nutricionais , China
9.
Int J Public Health ; 68: 1605344, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36712819

RESUMO

Objectives: This study aimed to compare the awareness of Chinese dietary guidelines (CDGs, 2016) between rural and urban areas in Southwest China and identify the factors that affect CDGs (2016) awareness. Methods: This cross-sectional survey included 8,320 individuals aged 18-75 years from Chongqing, Sichuan, Guizhou, and Yunnan, China. Convenience sampling method was adopted to select the survey subjects and face-to-face surveys in each region were conducted to collect data. Descriptive statistics and generalized linear model were used to evaluate differences in awareness of CDGs among urban and rural residents and its influencing factors. Results: Overall CDGs awareness was low in urban and rural areas, although the awareness rate was higher in the former than in the latter (29.1% vs. 19.9%, respectively). Region, education level, Body Mass Index (BMI), gender, income, and age are the influencing factors of CDGs awareness. Urban participants were likely to acquire relevant knowledge from social media, books/magazines, family/friends, and experts. However, rural participants were likely to acquire relevant knowledge from food sales staff (p < 0.05). Conclusion: Rural residents are less aware of CDGs than their urban counterparts in Southwest China. Future dietary education should adopt different strategies for different populations, with considerable focus on rural residents.


Assuntos
Dieta , População do Leste Asiático , Humanos , Estudos Transversais , China , Política Nutricional , População Rural , População Urbana
10.
Front Nutr ; 9: 985941, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36438728

RESUMO

Objective: Puerperae' dietary patterns (DPs) during the puerperium may be influenced by the mode of delivery, but population studies on this topic are scarce. This study aims to explore the relationship between DPs and different modes of delivery among puerperae. Methods: A cross-sectional study was conducted on 3,345 parturients in Lanzhou, China. The postpartum food intake was measured by a food frequency questionnaire (FFQ). Factor analysis was used to determine the DPs. Multiple linear regression was employed to examine the association between the mode of delivery and DP. Results: In this study, two DPs, i.e., traditional and modern DPs, were identified. Traditional DP was characterized by high energy-adjusted intake of tubers, coarse cereals, rice, whole grains, fishery products, and eggs. Modern DP included a high intake of coffee, non-sugary drinks, wine, tea, and fishery products. Compared with participants with vaginal delivery (reference category), cesarean section had an inverse association with modern DP (ß: -0.11, 95% CI: -0.36, -0.09). A significant interaction was found between education level, monthly household income, alcohol drinking, and modes of delivery. The inverse association between cesarean section and modern DP or the intake of coffee was significant among puerperae with higher or lower monthly household income. However, the inverse association between cesarean section and traditional DP was only found among puerperae with higher monthly household income. Moreover, among the participants with high education, cesarean section was positively associated with intake of vegetables. Conclusion: Cesarean puerperae with higher levels of education and those with lower and higher monthly household income had less unhealthy foods intake than those who had vaginal delivery. They need to be accounted for in educational programs and interventions focused on healthy diet recommendations in puerperium.

11.
Front Nutr ; 9: 888137, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35669068

RESUMO

Background: Information on nutrition literacy of middle schoolers is limited and tools for measuring nutrition literacy of middle schoolers are inadequate. Nutrition literacy has a positive effect on health. Improving children's nutrition literacy can help them to master the necessary nutritional knowledge, develop a healthy lifestyle, and learn to supplement nutrition according to their own needs for healthy growth. Objectives: To develop the Chongqing Middle school student Nutrition Literacy Scale (CM-NLS). Methods: Three experiments were conducted. A theoretical framework and an initial item pool of CM-NLS were established based on the literature review. And the two-round Delphi method was used to explore the suitable acceptance indicators and items. Item evaluation and reduction were performed using the classical test theory. Then, the items in the final CM-NLS were tested for their validity and reliability amongst 462 middle school students. The construct validity was assessed using exploratory factor analysis (EFA) and confirmatory factor analysis (CFA). The internal consistency reliability and split-half reliability were evaluated using Cronbach's alpha coefficients. Results: The final CM-NLS consisting of 52 items that were based on three primary items (functional, interactive and critical) and six sub-items (obtain, understand, apply, interact, medial literacy and critical skill) was developed and validated. EFA suggested six factors explaining 69.44% of the total variance (Kaiser-Meyer-Olkin test = 0.916, Bartlett's test χ2 = 5,854.037, P < 0.001). CFA showed that the model fit the data adequately, with χ2/df = 1.911, root mean square error of approximation = 0.063, goodness-of-fit index = 0.822 and adjusted goodness of fit index = 0.790. The total CM-NLS Cronbach's alpha values of internal consistency and split-half reliability were 0.849 and 0.521, respectively, with reasonable reliability. Conclusions: CM-NLS is a valid and reliable instrument for assessing nutrition literacy among middle school students in Chongqing. Specifically, it could be used by practitioners for needs assessment before the implementation of a nutrition education program.

12.
Front Public Health ; 10: 807526, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35372191

RESUMO

Nutrition literacy plays an important role in children's dietary habits and nutrition. This study aimed to analyse the status of nutrition literacy and its influencing factors amongst middle school students in Chongqing, China. "Nutrition literacy scale for middle school students in Chongqing" was used in 29 districts of Chongqing in September 2020. The scores of nutrition literacy and its' three sub-domains (functional, interactive and critical nutrition literacy) were divided into low and high groups based on their median scores. Binary logistic regression was used to measure the influencing factors of nutrition literacy. A total of 18,660 middle school students were included in this study. The median of nutrition literacy of middle school students was 61.68 (IQR = 14.37). Interactive nutrition literacy had the highest score (median = 70.00, IQR = 20.00), followed by functional nutrition literacy (median = 68.69, IQR = 14.14) and critical nutrition literacy (median = 45.83, IQR = 25.00). Students who were the minority (OR = 0.71, 95% CI = 0.637-0.785), in senior high school (OR = 0.51, 95% CI = 0.477-0.548), in rural areas (OR = 0.85, 95% CI = 0.790-0.911), receiving school meal support from the government (OR = 0.63, 95% CI = 0.591-0.664), with other caregivers' parenting (OR = 0.86, 95% CI = 0.805-0.914), with parents having a low level of education and with an abnormal BMI [thin (OR = 0.91, 95% CI = 0.837-0.990), overweight (OR = 0.87, 95% CI = 0.785-0.968), and obese (OR = 0.83, 95% CI = 0.767-0.902)] presented less probability of being a high level of nutrition literacy. Our results could assist public health authorities in developing strategies of nutrition literacy promotion for references and theoretical foundations.


Assuntos
Letramento em Saúde , Política Nutricional , Criança , China , Estudos Transversais , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Estudantes , Inquéritos e Questionários
13.
Nat Commun ; 12(1): 4291, 2021 07 13.
Artigo em Inglês | MEDLINE | ID: mdl-34257302

RESUMO

In utero base editing has the potential to correct disease-causing mutations before the onset of pathology. Mucopolysaccharidosis type I (MPS-IH, Hurler syndrome) is a lysosomal storage disease (LSD) affecting multiple organs, often leading to early postnatal cardiopulmonary demise. We assessed in utero adeno-associated virus serotype 9 (AAV9) delivery of an adenine base editor (ABE) targeting the Idua G→A (W392X) mutation in the MPS-IH mouse, corresponding to the common IDUA G→A (W402X) mutation in MPS-IH patients. Here we show efficient long-term W392X correction in hepatocytes and cardiomyocytes and low-level editing in the brain. In utero editing was associated with improved survival and amelioration of metabolic, musculoskeletal, and cardiac disease. This proof-of-concept study demonstrates the possibility of efficiently performing therapeutic base editing in multiple organs before birth via a clinically relevant delivery mechanism, highlighting the potential of this approach for MPS-IH and other genetic diseases.


Assuntos
Doenças por Armazenamento dos Lisossomos/genética , Doenças por Armazenamento dos Lisossomos/patologia , Animais , Modelos Animais de Doenças , Hepatócitos/metabolismo , Humanos , Mutação/genética , Miócitos Cardíacos/metabolismo
14.
Molecules ; 26(4)2021 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-33562613

RESUMO

Mastitis is a common disease in cows breeding. The milk quality will be significantly reduced with increased milk somatic cells, which often occurs in cows with mastitis. In this study, the influence of seasonal changes, age and lactation stages in the Dairy Herd Improvement (DHI) of cows was investigated. Then, the Dairy Herd Improvement (DHI) of cows with high somatic cell score (SCS) after melatonin treatment was systemically investigated. The results showed that melatonin significantly suppressed the milk somatic cell score under all of the tested conditions. The melatonin treatment also improved the milk nutritional value by reducing its fat but increasing its lactose and protein contents. The application of melatonin significantly improved the DHI. The beneficial effects of melatonin on DHI are likely attributed to the antioxidant and anti-inflammatory activities of melatonin.


Assuntos
Bovinos , Indústria de Laticínios , Melatonina/farmacologia , Animais , Bovinos/fisiologia , Contagem de Células , Feminino , Lactação/efeitos dos fármacos
15.
Appl Opt ; 59(26): 7918-7924, 2020 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-32976465

RESUMO

The electromagnetically induced transparency (EIT)-like effect can be generated in the metamaterial system, but most metamaterial systems are composed of complex and elaborated components (nanostructures) that cannot be removed or replaced easily. In this paper, a graphene grating is used to interact with random metal nanostructures (i.e., individual and connecting nanostructures) to induce the EIT-like effect through two destructive interference excitation pathways. Except for the new induced EIT-like mode, the overall original optical patterns (the shape and intensity of the transmission spectrum) remain unchanged as compared with the single metal nanostructure. Furthermore, due to the optical properties of graphene, the induced EIT-like effect was blueshifted as the Fermi energy of graphene increased. By depositing the graphene grating and the metal nanostructures on a gallium oxide substrate, the EIT-like effect was redshifted as the temperature of the environment increased. Through this study, the EIT-like effect induced by the graphene grating with a random metal nanostructure system was demonstrated by using a simple geometric system; further, the mechanism is easy and can be introduced to many different metamaterial systems to generate the EIT-like effect without changing other optical properties of the original metamaterial system. As such, this opens the door to broader applications for optical communication networks.

16.
Opt Express ; 28(14): 20563-20572, 2020 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-32680113

RESUMO

Circular dichroism (CD) has been widely studied in recent decades because of its wide application in biomedical detection. Nanostructures with different heights (NDH) usually increase the transmission CD effect. To achieve such nanostructures, one needs to repeatedly perform the electron-beam lithography (EBL) method twice or more, layer-by-layer, which is a very complicated process. Here, we propose a method to prepare NDH by combining the EBL and oblique angle deposition (OAD) techniques. L-shaped planar silver nanostructures are prepared using EBL and normal electron beam deposition, and the OAD method is then used to partially cover one arm of the L-shaped nanostructure. Numerical simulations reveal that the height difference in the two arms of the L-shaped NDH (LSNDH) causes a difference in the polarization directions of the left- (LCP) and right-circularly polarized (RCP) incident light, thereby, generating CD effects. A 2D material is used to cover the LSNDH to further increase the charge polarization direction differences, which considerably increases the CD effect. These results are useful in simplifying and increasing the convenience of the preparation method of 3D chiral nanostructures. Furthermore, the proposed nanostructure may have potential application in biosensor, such as chiral enantiomer sensors.

17.
PeerJ ; 8: e9147, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32461835

RESUMO

Cow mastitis is a major problem frequently encountered by dairy farmers and it is manifested by the high number of somatic cells and the low quality of the milk. The conventional treatment for mastitis is use of antibiotics. In the current study, a new approach is applied to target this disorder: rumen bypass melatonin feeding (RBMF). The RBMF significantly reduced milk somatic cell count and improved milk nutritional values with the elevated protein, fat and dry matter levels. This approach also suppresses the stress and proinflammatory responses of the cows indicated by the reduced serum cortisol, TNF-α and IL-6 and increased IL-10 levels. Importantly, the beneficial effects of RBMF have lasted for several days after termination of the treatment. The effects of melatonin on the mastitis are probably attributed to the antioxidant and anti-inflammatory activities of melatonin. Considering the none or low toxicity of melatonin to organisms and the no invasive nature of this approach, we recommend that RBMF could be used in large scale in the dairy farming to target the cow mastitis.

18.
Appl Opt ; 58(1): 177-181, 2019 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-30645527

RESUMO

Circular dichroism (CD) of nanostructures is in great demand for applications in biological molecules, photocurrent devices, and photocatalysis. Planar nanostructures can be prepared in a concise manner, and their CD effects have gained much research interest. In this study, tilted zigzag-shaped nanohole (TZSN) arrays are proposed, and the CD effect is studied by the finite element method. A strong resonance occurs in the gap by tuning the charge distributions between adjacent nanoholes. Meanwhile, the CD effect of TZSN arrays is strongly dependent on the structural parameters of TZSN. Results provide a novel method for tuning the CD effects of nanohole arrays on a film.

19.
Appl Opt ; 57(23): 6721-6724, 2018 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-30129627

RESUMO

Circular dichroism (CD) is a signal that characterizes the optical properties of chiral structures. Structures with intense CD signals have valuable applications in molecular chemistry, pharmaceuticals, and biosensing. This work proposes the use of a nanowire to increase the CD signal of crossed nanorods. The separation of resonant wavelengths of transmission under left-handed and right-handed circular polarization incidence (LCP and RCP) increases because the electric interaction between the upper nanorod and nanowire under LCP incidence is different from that under RCP incidence. The increased separation of resonant wavelengths, in turn, enhances the CD signals. In addition, two new CD modes appear, and these modes can be tuned by changing the structural parameters of the proposed structure. The present results will guide the design of plasmonic chiral nanostructures for enhancing the CD signal.

20.
Opt Express ; 26(2): 1199-1205, 2018 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-29401996

RESUMO

Asymmetric transmission (AT) holds significant applications in controlling polarization and propagation directions of electromagnetic waves. In this paper, tilted rectangular nanohole (TRNH) arrays in a square lattice are proposed to realize an AT effect. Numerical results show two AT modes in the transmission spectrum, and they are ascribed to the localized surface plasmon resonances around the two ends of TRNH and surface plasmon polaritons on the golden film. AT properties of the TRNH strongly depend on structural parameters, such as width, length, thickness, and tilted angle of TRNH. Results provide a novel mechanism for generating AT effect and offer potential plasmonic device applications, such as asymmetric wave splitters and optical isolators.

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