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OBJECTIVES: There is little evidence in the literature about the relationship between frailty and falls in older adults. Our objective was to explore the relationship between frailty and falls, and to analyze the effect factors (e.g., gender, different frailty assessment tools, areas, level of national economic development, and year of publication) of the association between frailty and falls among older adults. DESIGN: Systematic review and meta-analysis. SETTING AND PARTICIPANTS: Cohort studies that evaluated the association between frailty and falls in the older adults were included. We excluded any literature outside of cohort studies. METHODS: We did a systematic literature search of English databases PubMed, Scopus, Web of Science, EBSCOhost, and SciElO, as well as the Chinese databases CNKI, WANFANG, and VIP from 2001 until October 2022. The eligible studies were evaluated for potential bias using the Newcastle-Ottawa Scale (NOS). Study selection, data extraction and assessment of study quality were each conducted by two investigators. In Stata/MP 17.0 software, we calculated pooled estimates of the prevalence of falls by using a random-effects model, Subgroup analysis was conducted based on gender, different frailty assessment tools, areas, level of economic development, and year of publication. The results are presented using a forest plot. RESULTS: Twenty-nine studies were included in this meta-analysis and a total of 1,093,270 participants aged 65 years and above were enrolled. Among the older adults, frailty was significantly associated with a higher risk for falls, compared with those without frailty (combined RR-relative risk = 1.48, 95% CI-confidence interval: 1.27-1.73, I2=98.9%). In addition, the results of subgroup analysis indicated that men had a higher risk for falls than women among the older adults with frailty (RR 1.94, 95% CI: 1.18-3.2 versus RR 1.44, 95% CI: 1.24-1.67). Subgroup analysis by different frailty assessment tools revealed an increased risk of falls in older adults with frailty when assessed using the Frailty Phenotype (combined RR 1.32, 95%CI: 1.17-1.48), FRAIL score (combined RR 1.82, 95%CI: 1.36-2.43), and Study of Osteoporotic Fractures index (combined RR 1.54, 95%CI: 1.10-2.16). Furthermore, subgroup analysis by areas and level of national economic development found the highest fall risk in Oceania (combined RR 2.35, 95%CI: 2.28-2.43) and the lowest in Europe (combined RR 1.20, 95%CI: 1.05-1.38). Developed countries exhibited a lower fall risk compared to developing countries (combined RR 1.44, 95%CI: 1.21-1.71). Analysis by year of publication showed the highest fall risk between 2013-2019 (combined RR 1.79, 95%CI: 1.45-2.20) and the lowest between 2001-2013 (combined RR 1.21, 95%CI: 1.13-1.29). CONCLUSION: Frailty represents a significant risk factor for falls in older adults, with the degree of risk varying according to the different frailty assessment tools employed, and notably highest when using the FRAIL scale. Additionally, factors such as gender, areas, level of national economic development, and healthcare managers' understanding of frailty may all impact the correlation between frailty and falls. Thus, it's imperative to select suitable frailty diagnostic tools tailored to the specific characteristics of the population in question. This, in turn, facilitates the accurate identification of frailty in older adults and informs the development of appropriate preventive and therapeutic strategies to mitigate fall risk.
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Fraturas Ósseas , Fragilidade , Feminino , Humanos , Acidentes por Quedas/prevenção & controle , Fragilidade/epidemiologia , Fatores de Risco , Estudos de CoortesRESUMO
The larvae of Echinococcus (hydatidcyst) can parasitize humans and animals, causing a serious zoonotic disease-echinococcosis. The life history of Echinococcus is complicated, and as the disease progresses slowly after infection, early diagnosis is difficult to establish. Due to the limitations of imaging and immunological diagnosis in this respect, domestic and foreign scholars have established a variety of molecular detection techniques for the pathogen Echinococcus over recent years, mainly including nested polymerase chain reaction (PCR), multiplex PCR, real-time quantitative PCR, and nucleic acid isothermal amplification technology. In this article, the research progress of molecular detection technology for Echinococcus infection currently was reviewed and the significance of these methods in the detection and diagnosis of hydatid and hydatid diseases was also discussed.
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Equinococose , Echinococcus , Ácidos Nucleicos , Animais , Equinococose/diagnóstico , Echinococcus/genética , Humanos , Reação em Cadeia da Polimerase Multiplex/métodos , Sensibilidade e Especificidade , TecnologiaRESUMO
OBJECTIVE: To construct a cDNA library of Sparganum mansoni and immunoscreen antigen candidates for immunodiagnosis of sparganosis mansoni. METHODS: Total RNA was extracted from S. mansoni, and reversely transcribed into cDNA, which was ligated into the phage vector. These recombinant vectors were packaged in vitro to construct the SMART cDNA library of S. mansoni. Then, the cDNA library was immunoscreened with sera from patients with sparganosis mansoni to yield positive clones. The inserted fragments of positive clones were sequenced and subjected to homology analyses, and the structure and functions of the coding proteins were predicted. RESULTS: The SMATR cDNA library of S. mansoni was successfully constructed. The titer of the cDNA library was 6.25 × 106 pfu/mL, with a recombinant efficiency of 100%, and the mean length of the inserted fragments in the library was larger than 1 100 bp. A total of 12 positive clones were obtained by immunoscreening, and were categorized into Sm-I (Sm60-1), Sm-II (Sm58-1), Sm-III (Sm20-1) and Sm-IV (Sm22-3), with 1 134, 1 063, 883 bp and 969 bp long inserted fragments. Their coding proteins were highly homologous with the Spirometra erinaceieuropaei antigenic polypeptide, cytoplasmic antigen, ribosomal protein S4-like protein and unnamed protein product, respectively. CONCLUSIONS: A SMART cDNA library of S. mansoni has been successfully constructed and 4 categories of positive clones have been identified, which provides a basis for further studies on diagnostic antigens for sparganosis mansoni.
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Esparganose , Plerocercoide , Animais , Sequência de Bases , DNA Complementar/genética , Biblioteca Gênica , HumanosRESUMO
OBJECTIVE: To investigate the prevalence and risk factors of Blastocystis hominis infections among AIDS patients in Nanchang City. METHODS: A cross-sectional questionnaire survey was conducted among AIDS patients in Nanchang City during the period between May and September, 2016. B. hominis infection was detected in patients'stool samples using a PCR assay, and the CD4+ T cell count was measured in subjects'blood samples. In addition, the risk factors of B. hominis infection in AIDS patients were identified using univariate and multivariate logistic regression analyses. RESULTS: A survey was conducted in Nanchang City from May to September 2016. A total of 505 AIDS patients were investigated, and the prevalence of B. hominis infection was 4.16%. Univariate analysis revealed that B. hominis infection correlated with the occupation (χ2 = 8.595, P = 0.049), education level (χ2 = 14.494, P = 0.001), type of daily drinking water (χ2 = 10.750, P = 0.020), root of HIV infections (χ2 = 8.755, P = 0.026) and receiving anti-HIV therapy (χ2 = 23.083, P = 0.001) among AIDS patients, and multivariate logistic regression analysis identified daily direct drinking of tap water as a risk factor of B. hominis infections [odds ratio (OR) = 7.988, 95% confidential interval (CI): (1.160, 55.004)] and anti-HIV therapy as a protective factor of B. hominis infection [OR = 0.183, 95% CI: (0.049, 0.685)]. CONCLUSIONS: The prevalence of B. hominis is 4.16% among AIDS patients in Nanchang City. Daily direct drinking of tap water is a risk factor, and anti-HIV therapy is a protective factor of B. hominis infection among AIDS patients living in Nanchang City.
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Infecções Oportunistas Relacionadas com a AIDS , Síndrome da Imunodeficiência Adquirida , Infecções por Blastocystis , Infecções por HIV , Infecções Oportunistas Relacionadas com a AIDS/epidemiologia , Síndrome da Imunodeficiência Adquirida/complicações , Síndrome da Imunodeficiência Adquirida/epidemiologia , Infecções por Blastocystis/epidemiologia , Blastocystis hominis , China , Cidades , Estudos Transversais , Fezes/parasitologia , Infecções por HIV/complicações , Infecções por HIV/epidemiologia , Humanos , Prevalência , Fatores de RiscoRESUMO
OBJECTIVE: To investigate the prevalence and risk factors of Blastocystis infections among primary school students in Jiangjin District, Chongqing City. METHODS: A cross-sectional questionnaire survey was conducted among students sampled from a primary school in Jiangjin District, Chongqing City on April, 2018, and their stool samples were collected for microscopic examinations, in vitro culture and PCR assays to analyze the prevalence of Blastocystis infections and subtype of the parasite. In addition, the risk factors of Blastocystis infections among primary school students were identified using univariate analysis and multivariate logistic regression analysis. RESULTS: A total of 466 primary students were surveyed, and the subjects had a mean age of (9.81±1.66) years and included 236 males (50.64%) and 230 females (49.36%). The prevalence of Blastocystis infections was 15.24% (71/466) among the study students, and there was no significance difference in the prevalence between male and fe- male students (16.52% vs. 13.91%; χ2 = 0.616, P = 0.433). In addition, there was a significant difference in the prevalence of Blastocystis infections among grade 1 (6.35%, 4/63), grade 2 (5.17%, 3/58), grade 3 (21.74%, 15/69), grade 4 (25.30%, 21/83), grade 5 (10.19%, 11/108) and grade 6 students (20.00%, 17/85) (χ2 = 15.410, P = 0.009). There were four Blastocystis subtypes characterized (ST1, ST3, ST6 and ST7), in which ST6 was the most common subtype (45.07%, 32/71), followed by ST3 (25.35%, 18/71). Multivariate logistic regression analysis revealed that minority ethnicity [odds ratio (OR) = 4.259, 95% confidential inter- val (CI) : (1.161, 15.621)] and low maternal education level (primary school and below) [OR = 9.038, 95% CI: (1.125, 72.642)] were identified as risk factors of Blastocystis infection among primary school students in Jiangjin District, Chongqing City. CONCLUSIONS: There is a high prevalence of Blastocystis infections detected among primary school students in Jiangjin District, Chongqing City, and ST6 and ST3 are predominant subtypes. Minority ethnicity and low maternal education level (primary school and below) are risk factors for Blastocystis infections in primary school students.
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Infecções por Blastocystis , Infecções por Blastocystis/epidemiologia , Criança , China , Estudos Transversais , Fezes , Feminino , Humanos , Masculino , Prevalência , Fatores de Risco , Instituições Acadêmicas , EstudantesRESUMO
Strain-sensitive Ba x Sr1-x TiO3 perovskite systems are widely used because of their superior nonlinear dielectric behaviors. In this research, new heterostructures including paraelectric Ba0.5Sr0.5TiO3 (BSTO) and ferroelectric BaTiO3 (BTO) materials were epitaxially fabricated on flexible muscovite substrate. Through simple bending, the application of mechanical force can regulate the dielectric constant of BSTO from -77 to 36% and the channel current of BTO-based ferroelectric field effect transistor by two orders. The detailed mechanism was studied through the exploration of phase transition and determination of band structure. In addition, the phase-field simulations were implemented to provide theoretical support. This research opens a new avenue for mechanically controllable components based on high-quality oxide heteroepitaxy.
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OBJECTIVE: To understand the prevalence and risk factors of Blastocystis hominis infection in inpatients in Jiangjin District, Chongqing City. METHODS: A cross-sectional study was conducted in a community hospital in Jiangjin District, Chongqing City, and the inpatients were surveyed by questionnaires. After obtaining the informed consent from the inpatients or legal guardians, the stool and blood samples were collected and examined by microscopy and PCR from April 17 to May 1, 2018. The univariate analysis and logistic regression analysis were used to analyze the risk factors of the B. hominis infection. RESULTS: A total of 198 hospitalized patients were investigated, and the infection rate of B. hominis was 10.61% (21/198), and the infection rate of the females (12.10%) was higher than that of the males (8.11%), but the difference was not statistically significant. The highest rate of infection was 19.23% in the age group of 10 to 20 years, followed by 17.74% in the age group of 60 years and above, and the lowest rate was 2.38% in the age group of 20 to 40 years. The difference in infection rates of B. hominis among the different age groups was statistically significant (P < 0.05). The infection rate of B. hominis in the people who used dry pail latrines was 33.30%, which was higher than that of the people who used water flush toilets (9.10%) (P < 0.05). The genotypes of B. hominis were ST1, ST3, ST6 and ST7, and ST6 and ST3 being the most predominant genotypes which accounted for 47.62% (10/21) and 38.10% (8/21) respectively, and among the infected males, the genotypes were only ST3 and ST6. The multiple logistic regression analysis showed that among the factors affecting B. hominis infection, only keeping pets was a risk factor [OR = 3.798, 95% CI (1.245, 11.581), P < 0.05]. CONCLUSIONS: A high prevalence of B. hominis infection is found in the inpatients in Jiangjin District, Chongqing City, the predominant genotypes are ST6 and ST3, and keeping pets may be one of the main risk factors.
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Infecções por Blastocystis , Blastocystis hominis , Adolescente , Adulto , Infecções por Blastocystis/sangue , Infecções por Blastocystis/epidemiologia , Blastocystis hominis/genética , Criança , China/epidemiologia , Estudos Transversais , Fezes/parasitologia , Feminino , Hospitais/estatística & dados numéricos , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Fatores de Risco , Inquéritos e Questionários , Adulto JovemRESUMO
OBJECTIVE: To investigate the prevalence and risk factors of Blastocystis hominis infections among patients with HIV/AIDS in Fuyang City, Anhui Province. METHODS: A cross-sectional study was conducted in Fuyang City, Anhui Province in 2016. The demographic and socioeconomic status, and the lifestyle and production style were collected using a questionnaire survey. B. hominis DNA was detected in subjects'stool samples using a PCR assay, and the CD4+ T lymphocyte count and HIV viral load were measured in the subjects' blood samples. The risk factors of B. hominis infections among patients with HIV/AIDS were identified using univariate and multivariate logistic regression analyses. RESULTS: A total of 398 HIV/AIDS patients were enrolled in this study, with a mean age of 49.3 years, a mean body weight of 55.9 kg and a mean height of 164.4 cm. The prevalence of B. hominis infection was 6.78% in the study subjects, and no gender- (χ2 = 1.589, P = 0.207), education level- (χ2 =0.508, P = 0.776), marital status- (χ2 = 0.419, P = 0.811) or occupation-specific prevalence (χ2 = 2.744, P = 0.615) was detected. Among the patients with HIV/AIDS, there were no significant differences in the age (t = 0.370, P = 0.712), height (t = 1.587, P =0.113), body weight (t = 0.516, P = 0.606), CD4+ T lymphocyte count (t = 1.187, P = 0.230) or HIV viral load (t = 0.193, P =0.496) between B. hominis-infected and uninfected individuals. Dinking non-tap water [OR = 6.554, 95% CI: (1.876 to 22.903)] and keeping dogs [OR = 5.895, 95% CI: (2.017 to 17.225)] were identified as risk factors for B. hominis infection in patients with HIV/AIDS. CONCLUSIONS: The prevalence of B. hominis infection is high in HIV/AIDS patients, and drinking non-tap water and keeping dogs are risk factors for B. hominis infection among HIV/AIDS patients.
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Infecções por Blastocystis , Blastocystis hominis , Infecções por HIV , Animais , Infecções por Blastocystis/complicações , Infecções por Blastocystis/epidemiologia , Estudos Transversais , Cães , Fezes/parasitologia , Feminino , HIV , Infecções por HIV/complicações , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Fatores de RiscoRESUMO
BACKGROUND: Whether individuals with autism spectrum disorder (ASD) have impairments with biological motion perception has been debated. The present study examined the ability to identify point-light-displayed (PLD) human actions in neurotypical (NT) adults and adults with ASD. METHOD: Twenty-seven adults with ASD (mean age = 28.36) and 30 NT adults (mean age = 22.45) were tested. Both groups viewed 10 different biological motion actions contacting an object/tool and 10 without making contact. Each action was presented twice, and participant's naming responses and reaction times were recorded. RESULTS: The ASD group had a significantly lower total number of correct items (M = 29.30 ± 5.08 out of 40) and longer response time (M = 4550 ± 1442 ms) than NT group (M = 32.77 ± 2.78; M = 3556 ± 1148 ms). Both groups were better at naming the actions without objects (ASD group: 17.33 ± 2.30, NT group: 18.67 ± 1.30) than those with objects (ASD group: 11.96 ± 3.57, NT group: 14.10 ± 1.97). Correlation analyses showed that individuals with higher Autism-spectrum Quotient scale scores tended to make more errors and responded more slowly. CONCLUSION: Adults with ASD were able to identify human point-light display biological motion actions much better than chance; however, they were less proficient compared with NT adults in terms of accuracy and speed, regardless of action type.
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Transtorno do Espectro Autista/fisiopatologia , Percepção de Movimento/fisiologia , Desempenho Psicomotor/fisiologia , Adulto , Feminino , Humanos , Masculino , Adulto JovemRESUMO
BACKGROUND: Azelastine hydrochloride (azelastine) nasal spray is a histamine receptor-1 (H1) antagonist often used in treating allergic rhinitis to relieve its symptoms. However, the effects of azelastine to influence decongestion on human nasal mucosa in patients with allergic rhinitis are not yet fully explored and merit further exploration. The effects of azelastine on the vasocontractile responses generated by smooth muscles in the vascular structures of human nasal mucosa were investigated directly in vitro. METHODS: We examined the effectiveness of azelastine on isolated human nasal mucosa by testing: 1) the effect on mucosa resting tension; 2) the effect on mucosal contraction caused by 10-6 M methoxamine as a sympathetic mimetic; 3) the effect of the drugs on electrically induced mucosal contractions. RESULTS: The results indicated that addition of methoxamine to the incubation medium caused the nasal mucosa to contract in a dose-dependent manner. Addition of azelastine at doses of 10â"6 M or above elicited a significant dilation response to 10â"6 M methoxamine-induced mucosal contraction. Azelastine could inhibit electrical field stimulation-induced spike mucosal contraction. Moreover, increase in concentration of azelastine had minimal effect on basal tension of nasal mucosa. CONCLUSIONS: The technique in our study is simple and reproducible. Azelastine could inhibit both EFS and methoxamine-induced nasal mucosal contractions in vitro. This study highlights that although azelastine nasal spray is often used in treating allergic rhinitis to improve symptoms, nasal obstruction may be not relieved immediately due to the anti-sympathetic effect of azelastine.
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Anti-Inflamatórios não Esteroides , Mucosa Nasal , Ftalazinas , Rinite Alérgica , Rinite , Administração Intranasal , Anti-Inflamatórios não Esteroides/farmacologia , Anti-Inflamatórios não Esteroides/uso terapêutico , Método Duplo-Cego , Humanos , Mucosa Nasal/efeitos dos fármacos , Sprays Nasais , Ftalazinas/farmacologia , Ftalazinas/uso terapêutico , Rinite/tratamento farmacológicoRESUMO
OBJECTIVES: Sumatriptan (Imigran) is a potent and highly selective 5-HT1 receptor agonist often used in treating acute migraine. Intranasal sumatriptan is well absorbed and is generally effective in relieving headache. However, the effects of Imigran on human nasal mucosa have rarely been well explored, to verify the effect of Imigran, which act on human nasal mucosa directly in vitro. DESIGN AND PARTICIPANTS: We examined the effectiveness of Imigran on human nasal mucosa by testing: (i) effect on human nasal mucosa resting tension; (ii) effect on contraction caused by 10-6 mol/L methoxamine as a sympathetic mimetic; and (iii) effect of the drugs on electrically induced on human nasal mucosa contractions. RESULTS: The results indicated that addition of methoxamine to the incubation medium caused the nasal mucosa to contract in a dose-dependent manner. Addition of Imigran at doses of 10-4 mol/L elicited a significant relaxation response to 10-6 mol/L methoxamine-induced contraction. Imigran could not inhibit electrical field stimulation-induced spike contraction. It also had a minimal effect on the basal tension of nasal mucosa as the concentration increased. CONCLUSIONS: The study indicated that high concentrations of Imigran had a significant spasmolytic effect by antagonising α-adreoceptors and nasal obstruction could not be released in the patient combined with acute migraine and stuffy nose by concomitant α-adrenergic agonist nasal spray plus Imigran nasal spray.
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We map electronic states, band gaps, and interface-bound charges at termination-engineered BiFeO3/La0.7Sr0.3MnO3 interfaces using atomically resolved cross-sectional scanning tunneling microscopy. We identify a delicate interplay of different correlated physical effects and relate these to the ferroelectric and magnetic interface properties tuned by engineering the atomic layer stacking sequence at the interfaces. This study highlights the importance of a direct atomically resolved access to electronic interface states for understanding the intriguing interface properties in complex oxides.
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Objective: The objective was to identify the incidence of influenza-like syndromes and related health behavior factors among Beijing residents. Methods: From December 6, 2013 to January 16, 2014, we selected 150 villages or communities from 30 towns or streets as survey locations using a multi-stage random sampling method, and then conducted a cross-sectional study among 7 354 residents who aged 18 years or above and had live in Beijing for more than a half year using self-administered anonymous questionnaires, and totally 7 327 valid questionnaires are collected. The questionnaire consisted of demographic information, self-reported influenza-like syndromes in the past two weeks, and health behaviors. Multiple logistic regression models were used to identify the factors associated with self-reported influenza-like syndromes. Results: The mean (SD) age of the partcipants was 44.6 (15.2) years. Among them, 6.9% (506 cases) reported having influenza like illness during the past two weeks. The multiple logistic regression analysis indicated that regular physical exercise, optimal hand hygiene, and avoidance of going to the crowded places during respiratory infectious disease epidemics were significantly associated with a lower likelihood of reporting influenza-like syndromes, compared with those without regular physical exercises, without optimal hand hygiene, and not avoiding going to the crowded places, and the OR(95%CI) were 0.80 (0.66-0.97), 0.75 (0.57-0.99) and 0.80 (0.65-0.98), respectively. Conclusion: Personal health behaviors were associated with the incidence of respiratory infectious diseases such as influenza in Beijing, and future interventions to improve personal hygiene behaviors are needed to prevent the spread of respiratory infectious diseases.
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Comportamentos Relacionados com a Saúde , Influenza Humana/epidemiologia , Pequim , Estudos Transversais , Humanos , Incidência , Infecções Respiratórias , Meio Social , Inquéritos e Questionários , SíndromeRESUMO
Objective: To investigate human exposure to live poultry (poultry feeding and purchasing) in the residents in Beijing and related factors during the second wave of avian influenza A(H7N9) epidemic during 2013-2014, and provide scientific evidence for avian influenza prevention and control. Methods: A total of 7 366 adults aged ≥18 years were selected through multi-stage stratified sampling in Beijing for a questionnaire survey. Logistic regression model was used to analyze the influence factors of human exposure to live poultry. Results: The live poultry feeding rate and live poultry purchasing rate in residents in Beijing in the past year were 5.3% (95%CI: 4.8%-5.8%) and 6.0% (95%CI: 5.5%-6.5%) respectively. Logistic regression analysis indicated that lower educational level of primary school and below, (OR=1.82, 95%CI: 1.22-2.72); being farmer (OR=2.49, 95%CI:1.89-3.29) or being unemployed (OR=1.65, 95%CI: 1.08-2.52); being non local resident (OR=1.54, 95%CI: 1.10-2.16); living in suburban area (OR=2.36, 95%CI: 1.77-3.16); having one child (OR=1.76, 95%CI: 1.42-2.17) or ≥2 children (OR=2.15, 95%CI: 1.43-3.22) in the family were the risk factors associated with feeding poultry compared with higher educational level of college and above, being employed, being local resident, living in urban area and having no child. And being farmer (OR=1.61, 95%CI: 1.27-2.02); being non local resident (OR=1.76, 95%CI: 1.31-2.35); living in suburban area (OR=2.05, 95%CI: 1.61-2.61); having one child (OR=1.24, 95%CI: 1.02-1.52) or ≥2 children (OR=1.78, 95%CI: 1.21-2.63) were the risk factors for purchasing live poultry. Conclusion: Some residents living in Beijing still have exposure to live poultry, and targeted measures should be taken to reduce the exposure to poultry.
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Epidemias , Subtipo H7N9 do Vírus da Influenza A/patogenicidade , Influenza Humana/epidemiologia , Aves Domésticas/virologia , Adolescente , Adulto , Animais , Pequim , Criança , China/epidemiologia , Surtos de Doenças , Fazendeiros , Feminino , Humanos , Subtipo H7N9 do Vírus da Influenza A/isolamento & purificação , Influenza Aviária/epidemiologia , Influenza Humana/diagnóstico , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Médicos , Fatores de Risco , Inquéritos e QuestionáriosRESUMO
Herein, debris particulates of nanoporous silver (np-Ag) were synthesised by a dealloying method, and their integration behaviour and surface-enhanced Raman scattering (SERS) properties during iodine functionalisation were examined. It was found that the dealloyed np-Ag debris particulates gradually assembled to form rigid nanoporous microspheres comprising Ag nano-ligaments due to mechanical collisions during iodine treatment. High-resolution transmission electron microscopy and X-ray photoelectron microscopy clearly showed the iodide surface of np-Ag, which was dotted with iodine or iodide 'nanoislands'. The exceptional, and unexpected, integration and surface structures result in a highly enhanced localised surface plasmon resonance. Furthermore, the robust nanoporous microspheres can be employed individually as as-produced miniaturised electrodes to electrically enrich target molecules at parts-per-trillion levels, so as to achieve charge selectivity and superior detectability compared with the ordinary SERS effect.
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The strong coupling between antiferromagnetism and ferroelectricity at room temperature found in BiFeO3 generates high expectations for the design and development of technological devices with novel functionalities. However, the multi-domain nature of the material tends to nullify the properties of interest and complicates the thorough understanding of the mechanisms that are responsible for those properties. Here we report the realization of a BiFeO3 material in thin film form with single-domain behaviour in both its magnetism and ferroelectricity: the entire film shows its antiferromagnetic axis aligned along the crystallographic b axis and its ferroelectric polarization along the c axis. With this we are able to reveal that the canted ferromagnetic moment due to the Dzyaloshinskii-Moriya interaction is parallel to the a axis. Furthermore, by fabricating a Co/BiFeO3 heterostructure, we demonstrate that the ferromagnetic moment of the Co film does couple directly to the canted moment of BiFeO3.
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The metallic interface between insulating LaAlO3 and SrTiO3 opens up the field of oxide electronics. With more than a decade of researches on this heterostructure, the origin of the interfacial conductivity, however, remains unsettled. Here we resolve this long-standing puzzle by atomic-scale observation of electron-gas formation for screening hidden lattice instabilities, rejuvenated near the interface by epitaxial strain. Using atomic-resolution imaging and electron spectroscopy, the generally accepted notions of polar catastrophe and cation intermixing for the metallic interface are discounted. Instead, the conductivity onset at the critical thickness of 4-unit cell LaAlO3 on SrTiO3 substrate is accompanied with head-to-head ferroelectric-like polarizations across the interface due to strain-rejuvenated ferroelectric-like instabilities in the materials. The divergent depolarization fields of the head-to-head polarizations cast the interface into an electron reservoir, forming screening electron gas in SrTiO3 with LaAlO3 hosting complementary localized holes. The ferroelectric-like polarizations and electron-hole juxtaposition reveal the cooperative nature of metallic LaAlO3/SrTiO3.
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Comportamentos Relacionados com a Saúde , Influenza Humana/prevenção & controle , Classe Social , Adolescente , Adulto , Pequim , Estudos Transversais , Feminino , Higiene das Mãos/estatística & dados numéricos , Humanos , Vacinas contra Influenza/administração & dosagem , Masculino , Máscaras/estatística & dados numéricos , Pessoa de Meia-Idade , Adulto JovemRESUMO
Recent developments in high-temperature superconductivity highlight a generic tendency of the cuprates to develop competing electronic (charge) supermodulations. While coupled with the lattice and showing different characteristics in different materials, these supermodulations themselves are generally conceived to be quasi-two-dimensional, residing mainly in individual CuO2 planes, and poorly correlated along the c axis. Here we observed with resonant elastic X-ray scattering a distinct type of electronic supermodulation in YBa2Cu3O(7-x) (YBCO) thin films grown epitaxially on La0.7Ca0.3MnO3 (LCMO). This supermodulation has a periodicity nearly commensurate with four lattice constants in-plane, eight out of plane, with long correlation lengths in three dimensions. It sets in far above the superconducting transition temperature and competes with superconductivity below this temperature for electronic states predominantly in the CuO2 plane. Our finding sheds light on the nature of charge ordering in cuprates as well as a reported long-range proximity effect between superconductivity and ferromagnetism in YBCO/LCMO heterostructures.