Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 19 de 19
Filtrar
1.
Meat Sci ; 213: 109481, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38461675

RESUMEN

Beef is a popular meat product that can spoil and lose quality during postharvest handling and storage. This review examines different preservation methods for beef, from conventional techniques like low-temperature preservation, irradiation, vacuum packing, and chemical preservatives, to novel approaches like bacteriocin, essential oil, and non-thermal technologies. It also discusses how these methods work and affect beef quality. The review shows that beef spoilage is mainly due to enzymatic and microbial activities that impact beef freshness, texture, and quality. Although traditional preservation methods can extend beef shelf life, they have some drawbacks and limitations. Therefore, innovative preservation methods have been created and tested to improve beef quality and safety. These methods have promising results and potential applications in the beef industry. However, more research is needed to overcome the challenges and barriers for their commercialization. This review gives a comprehensive and critical overview of the current and emerging preservation methods for beef and their implications for the beef supply chain.


Asunto(s)
Conservación de Alimentos , Carne Roja , Animales , Bovinos , Conservación de Alimentos/métodos , Carne Roja/microbiología , Almacenamiento de Alimentos/métodos , Conservantes de Alimentos/farmacología , Microbiología de Alimentos , Vacio , Manipulación de Alimentos/métodos
3.
Chest ; 2023 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-37977264

RESUMEN

BACKGROUND: Several characteristics distinguish lung cancer in female patients from that in male patients, with adenocarcinoma being more prevalent in female patients and occurring more frequently in female patients who do not smoke. Uncertainty surrounds the relationship between female-specific reproductive factors and lung cancer risk. RESEARCH QUESTION: Are sex-specific reproductive factors associated with risk of lung cancer in different genetic risk groups and histologic types? STUDY DESIGN AND METHODS: A Cox proportional hazard model was used to evaluate the association between multiple reproductive factors and the risk of lung cancer developing in a prospective cohort study involving 273,190 female individuals from the UK Biobank. Subgroup analyses stratified by age, smoking status, BMI, genetic risk, and histologic subtype were conducted to emphasize the modification effects further. RESULTS: A total of 1,182 cases of lung cancer in female patients were recorded over a median follow-up period of 12.0 years in the cohort study. In multivariable-adjusted models, early menarche (age ≤ 11 years: hazard ratio [HR], 1.22; 95% CI, 1.03-1.46), early menopause (age ≤ 46 years: HR, 1.49; 95% CI, 1.19-1.86), a shorter reproductive span (≤ 32 years: HR, 1.42; 95% CI, 1.18-1.71; and 33-35 years: HR, 1.24; 95% CI, 1.00-1.53), and early age at first birth (age ≤ 20 years: HR, 1.63; 95% CI, 1.33-2.01) were associated with a higher risk of lung cancer. Stratified analysis revealed that several reproductive factors, including early age at menopause, shortened reproductive span, and early age at first birth, showed a substantially stronger relationship with an elevated risk of lung cancer, particularly of lung adenocarcinoma, in populations with high genetic risk and more detrimental behaviors. INTERPRETATION: Early age at menopause, a shortened reproductive life span, and early age at first birth were associated with higher risks of lung cancer, particularly of lung adenocarcinoma, in a subpopulation with higher genetic susceptibility and detrimental behaviors. The evidence provided by this study emphasizes the significance of screening for multiple reproductive factors to prevent lung cancer among female individuals.

4.
Lung Cancer ; 184: 107358, 2023 10.
Artículo en Inglés | MEDLINE | ID: mdl-37696218

RESUMEN

OBJECTIVES: Leukocyte telomere length (LTL) is associated with a wide variety of diseases, including cancer. However, findings regarding the association between LTL and the risk for lung cancer have been inconclusive and inconsistent across previous observational studies. METHODS: This prospective cohort study included data from 425,146 participants 37-73 years of age housed in the UK Biobank. Quantitative polymerase chain reaction (qPCR) was used to measure LTL in baseline DNA samples. A multivariate Cox proportional hazards model was used to evaluate the relationship between LTL and the risk for lung cancer. RESULTS: An increase in LTL per interquartile range (IQR) was associated with a 9% increase in the risk for lung cancer (hazard ratio [HR] 1.09 [95% confidence interval (CI) 1.03-1.16]). Participants in the highest LTL quintile exhibited an approximately 25% elevated risk for developing lung cancer (HR 1.25 [95% CI 1.09-1.45]) compared with those in the lowest quintile. The relationship between per IQR increase in LTL and elevated risk for lung cancer was greater in the histological subtype of adenocarcinoma (HR 1.30 [95% CI 1.18-1.43]), female sex (HR 1.16 [95% CI 1.06-1.26]), non-smokers (HR 1.45 [95% CI 1.23-1.71]), and individuals with high genetic risk for lung cancer (HR 1.18 [95% CI 1.03-1.34]), respectively. Surprisingly, a per IQR increase in LTL was associated with increased risks for both lung adenocarcinoma (HR 1.56 [95% CI 1.24-1.96]) and squamous cell carcinoma (HR 2.01 [95% CI 1.13-3.56]) in never smokers. CONCLUSIONS: Longer LTL was associated with an elevated risk for lung cancer, particularly for adenocarcinoma and squamous cell carcinoma in never smokers. The results suggest the potential of telomeres as non-invasive biomarkers for the early screening of lung cancer, particularly in non-smokers, who are typically overlooked.


Asunto(s)
Adenocarcinoma , Carcinoma de Células Escamosas , Neoplasias Pulmonares , Femenino , Humanos , Neoplasias Pulmonares/epidemiología , Neoplasias Pulmonares/genética , Bancos de Muestras Biológicas , Estudios Prospectivos , Telómero/genética , Reino Unido/epidemiología
5.
Front Nutr ; 10: 1222499, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37457981

RESUMEN

Introduction: Vitamin D has been known to be associated with asthma, particularly in children, while the evidence among adults is limited and inconclusive. This study aimed to investigate the association between serum, vitamin D concentrations, and the incidence of adult-onset asthma and also the modified effect caused by sleep patterns and genetic risks. Methods: A prospective cohort study with 307,872 participants aged between 37 and 73 years was conducted based on the UK Biobank, with a median follow-up of 12 years. The Cox proportional hazard model was applied to evaluate the association between vitamin D status and incident adult-onset asthma, and the modified effect was investigated by conducting stratified analysis according to sleep pattern score and genetic risk score, and subgroup analyses were performed by sex, age, BMI, and smoking status as well. Results: Individuals with optimal vitamin D concentration were associated with 11.1% reduced risk of incident asthma compared to those participants with deficient vitamin D (HR = 0.889; 95% CI: 0.820-0.964; p = 0.005). Moreover, stratification analysis demonstrated that the protective effect of vitamin D on asthma risk was modified by sleep patterns or genetic susceptibility, with the strongest protective effect being observed in the subpopulation with a moderate sleep pattern (HR = 0.883; 95% CI: 0.797-0.977; p = 0.016) and a moderate genetic risk (HR = 0.817; 95% CI: 0.711-0.938; p = 0.004). In subgroup analyses, the protective effect of optimal vitamin D levels was only significant among men, individuals younger than 60 years of age, overweight individuals, and current or previous smokers. Conclusion: Increased serum vitamin D levels were associated with a lower risk of incident adult-onset asthma, and this association was modified by sleep patterns and genetic predisposition to some extent.

6.
ERJ Open Res ; 9(2)2023 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-37057096

RESUMEN

Background: Both genetic and lifestyle factors contribute to the development of asthma, but whether unfavourable lifestyle is associated with similar increases in risk of developing asthma among individuals with varying genetic risk levels remains unknown. Methods: A healthy lifestyle score was constructed using body mass index, smoking status, physical activities and dietary pattern to further categorise into ideal, intermediate and poor groups. Genetic risk of asthma was also categorised as three groups based on the tertiles of polygenic risk score established using 212 reported and verified single-nucleotide polymorphisms of European ancestry in the UK Biobank study. We examined the risk of incident asthma related with each lifestyle level in each genetic risk group by Cox regression models. Results: Finally, 327 124 participants without baseline asthma were included, and 157 320 (48.1%) were male. During follow-up, 6238 participants (1.9%) developed asthma. Compared to ideal lifestyle in a low genetic risk group, poor lifestyle was associated with a hazard ratio of up to 3.87 (95% CI, 2.98-5.02) for developing asthma in a high genetic risk group. There was interaction between genetic risk and lifestyle, and the population-attributable fraction of lifestyle and genetic risk were 30.2% and 30.0% respectively. Conclusion: In this large contemporary population, lifestyle and genetic factors jointly play critical roles in the development of asthma, and the effect values of lifestyle on incident adult-onset asthma were greater than that of genetic risk. Our findings highlighted the necessity of a comprehensive intervention for the prevention of asthma despite the genetic risk.

7.
Ecotoxicol Environ Saf ; 257: 114922, 2023 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-37080133

RESUMEN

BACKGROUND: Numerous studies have explored the association of air pollution with asthma but have yielded conflicting results. The exact role of air pollution in the incidence of adult-onset asthma and whether this effect is modified by genetic risk, lifestyle, or their interaction remain uncertain. METHODS: We conducted a prospective cohort study on 298,738 participants (aged 37-73 years) registered in the UK Biobank. Cox proportional hazard models were used to evaluate the association of air pollution, including particulate matter (PM2.5, PMcoarse, and PM10), nitrogen dioxide (NO2), and nitrogen oxides (NOx), with asthma incidence. We constructed genetic risk and lifestyle scores, assessed whether the impact of air pollution on adult-onset asthma risk was modified by genetic susceptibility or lifestyle factors, and evaluated the identified interactions. RESULTS: We found that each interquartile range increase in annual concentrations of PM2.5, NO2, and NOx was related to 1.04 (95% confidence interval [CI]: 1.01, 1.08), 1.04 (95% CI: 1.00, 1.08), and 1.03 (95% CI: 1.00, 1.06) times the risk of adult-onset asthma, respectively. The size of the effect of air pollution was greater among subpopulations with low genetic risk or unfavorable lifestyles. We also identified an additive interaction effect of air pollution with lifestyle factors, but not with genetic risk, on the risk of adult-onset asthma. CONCLUSION: Our analyses show that air pollution increases the risk of adult-onset asthma, but that the size of the effect is modified by lifestyle and genetic risk. These findings emphasize the need for integrated interventions for environmental pollution by the government as well as adherence to healthy lifestyles to prevent adult-onset asthma.


Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire , Asma , Humanos , Adulto , Contaminantes Atmosféricos/efectos adversos , Contaminantes Atmosféricos/análisis , Dióxido de Nitrógeno/análisis , Estudios Prospectivos , Exposición a Riesgos Ambientales/análisis , Contaminación del Aire/efectos adversos , Contaminación del Aire/análisis , Material Particulado/efectos adversos , Material Particulado/análisis , Asma/etiología , Asma/genética , Estilo de Vida
8.
J Gen Intern Med ; 38(10): 2354-2363, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-36988870

RESUMEN

BACKGROUND: Multiple studies showed sex discrepancies in the prevalence, incidence, and disease control of asthma. The relationships between different reproductive factors and the risk of asthma in females remain uncertain. DESIGN: A prospective cohort study recruited 239,701 female participants from the UK Biobank. The Cox proportional hazard model and multiple adjusted restricted cubic splines were used to evaluate the association between each reproductive factor and the risk of adult-onset asthma. KEY RESULTS: We observed that the association of age at menarche and age of menopause with adult-onset asthma risk presented as U-shaped, with multiple adjusted HRs for age at menarche being 1.129 (95% CI, 1.038-1.228) for ≤ 11 years old and 1.157 (95% CI, 1.058-1.265) for ≥ 15 years old referenced to 13 years old, and for age at menopause being 1.368 (1.237-1.512) for ≤ 46 years old and 1.152 (1.026-1.294) for ≥ 55 years old referenced to 50-52 years old. Early age at first live birth (≤ 20 years old), a greater number of miscarriages (≥ 2) or stillbirths (≥ 2), more children (≥ 4), and shorter reproductive years (≤ 32 years) were associated with elevated risk of asthma. In addition, history of hysterectomy or oophorectomy was associated with increased risk of adult-onset asthma, particularly in those with simultaneous hysterectomy and oophorectomy (HR, 1.239; 95% CI, 1.063-1.445). For exogenous sex hormones, hormone replacement therapy (HR, 1.482; 95% CI, 1.394-1.574) was identified to be associated with elevated risk of adult-onset asthma. CONCLUSIONS: This study not only demonstrated significant associations between multiple reproductive factors and the risk of adult-onset asthma in a female's later life, but also found that history of hysterectomy or oophorectomy, as well as hormone replacement therapy, was linked to an elevated incidence of adult-onset asthma. Our findings highlighted the significance of reproductive factors in the development of asthma in female populations.


Asunto(s)
Asma , Menopausia , Niño , Adulto , Femenino , Humanos , Adulto Joven , Adolescente , Persona de Mediana Edad , Factores de Riesgo , Estudios Prospectivos , Menarquia , Asma/epidemiología , Asma/etiología
9.
Environ Res ; 218: 114996, 2023 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-36481370

RESUMEN

OBJECTIVES: The effect of air pollution exposure on incident lung cancer remains uncertain, and the modifying role of lifestyle and genetic susceptibility in association between air pollution and lung cancer is ambiguous. METHODS: A total of 367,623 participants from UK biobank cohort were enrolled in the analysis. The concentrations of particle matter (PM2.5, PM10), nitrogen dioxide (NO2), and nitrogen oxides (NOx), were evaluated by land-use regression model. Cox proportional hazard model was applied to assess the associations between air pollution and incident lung cancer. A lifestyle risk score and a polygenic risk score were established to investigate whether lifestyle and heritable risk could modify the effect of air pollution on lung cancer risk. RESULTS: Per interquartile range (IQR) increment in annual concentrations of PM2.5 (HR = 1.22, 95% CI, 1.15∼1.30), NO2 (HR = 1.19, 95% CI, 1.10∼1.27), and NOx (HR = 1.14, 95% CI, 1.09∼1.20) were associated with increased risk of lung cancer. We observed an additive interaction between air pollution including PM2.5 and NOx and lifestyle or genetic risk. Individuals with high air pollution exposure, poor lifestyle and high genetic risk had the highest risk of incident lung cancer. CONCLUSION: Long-term exposures to air pollution is associated with increased risk of lung cancer, and this effect was modified by lifestyle or genetic risk. Integrated interventions for environmental pollution by government and adherence to healthy lifestyle by individuals are advocated for lung cancer prevention.


Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire , Neoplasias Pulmonares , Humanos , Contaminantes Atmosféricos/toxicidad , Contaminantes Atmosféricos/análisis , Dióxido de Nitrógeno/análisis , Material Particulado/análisis , Estudios Prospectivos , Estudios de Cohortes , Exposición a Riesgos Ambientales/análisis , Contaminación del Aire/efectos adversos , Contaminación del Aire/análisis , Neoplasias Pulmonares/inducido químicamente , Neoplasias Pulmonares/epidemiología , Estilo de Vida
10.
Front Cell Infect Microbiol ; 12: 1014530, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36325463

RESUMEN

Purpose: Leptospirosis is a zoonotic disease caused by pathogenic spirochetes of the genus Leptospira. However, there is currently no consensual definition or diagnostic criteria for severe and different forms of leptospirosis. Therefore, more insight on clinical manifestations, risk factors, and outcomes of leptospirosis is warranted. The identification of leptospirosis with distinct clinical manifestations and prognosis in our population. Methods: Multiple correspondence analysis and hierarchical classification on principal components were presented to identify different clinical types of leptospirosis. The outcomes were clinical phenotypes, laboratory and imaging findings, and prognosis. Results: The 95 enrolled patients had median values of 54.0 years (39.0-65.0) for age, 9.0 (7.0-14.0) for total hospital stay lengths, of whom 86.3% was male and 40.0% was transferred to ICU. Three clinical types were distinguished: mild leptospirosis (n=43, 45.3%) with less organ dysfunction and shorter hospital stays; respiratory leptospirosis (n=28, 29.5%) with hemoptysis, and respiratory and circulatory failure; and hepato-renal leptospirosis (n=24, 25.3%) with worst liver and kidney dysfunction. Total hospital mortality was 15.8% and was associated with dyspnea and high levels of neutrophil counts. Conclusions: The identification of leptospirosis with distinct clinical manifestations and prognosis in our population may assist clinicians to distinguish leptospirosis-like disease. Moreover, dyspnea and neutrophil count were found to be independent risk factors for severe leptospirosis progression.


Asunto(s)
Leptospira , Leptospirosis , Animales , Masculino , Leptospirosis/diagnóstico , Estudios Retrospectivos , Zoonosis , Disnea/complicaciones
11.
Sensors (Basel) ; 22(21)2022 Nov 06.
Artículo en Inglés | MEDLINE | ID: mdl-36366240

RESUMEN

The rapidly growing power data in smart grids have created difficulties in security management. The processing of large-scale power data with the use of artificial intelligence methods has become a hotspot research topic. Considering the early warning detection problem of smart meters, this paper proposes an abnormal data detection network based on Deep Reinforcement Learning, which includes a main network and a target network composed of deep learning networks. This work uses the greedy policy algorithm to find the action of the maximum value of Q based on the Q-learning method to obtain the optimal calculation policy. It also uses the reward value and discount factor to optimize the target value. In particular, this study uses the fuzzy c-means method to predict the future state information value, which improves the computational accuracy of the Deep Reinforcement Learning model. The experimental results show that compared with the traditional smart meter data anomaly detection method, the proposed model improves the accuracy of meter data anomaly detection.


Asunto(s)
Inteligencia Artificial , Refuerzo en Psicología , Algoritmos , Recompensa
12.
Nutrients ; 14(19)2022 Sep 28.
Artículo en Inglés | MEDLINE | ID: mdl-36235690

RESUMEN

Background: Previous observational studies investigated the relationship between coffee and tea intake and the risk of asthma, however, the conclusions were inconsistent. Further, the combined effect of coffee and tea consumption on asthma has rarely been studied. Methods: We examined associations between the self-reported intake of tea and coffee and the risk of incident asthma in a total of 424,725 participants aged from 39 to 73 years old from the UK Biobank. Cox proportional hazards models were used to estimate the associations between coffee/tea consumption and incident adult-onset asthma, adjusting for age, sex, race, smoking status, body mass index (BMI), education, and Townsend deprivation index. Results: Cox models with penalized splines showed J-shaped associations of coffee, tea, caffeinated coffee, and caffeine intake from coffee and tea with the risk of adult-onset asthma (p for nonlinear <0.01). Coffee intake of 2 to 3 cups/d (hazard ratio [HR] 0.877, 95% confidence interval [CI] 0.826−0.931) or tea intake of 0.5 to 1 cups/d (HR 0.889, 95% CI 0.816−0.968) or caffeinated coffee intake of 2 to 3 cups/d (HR 0.858, 95% CI 0.806−0.915) or combination caffeine intake from tea and coffee of 160.0 to 235.0 mg per day (HR 0.899, 95% CI 0.842−0.961) were linked with the lowest hazard ratio of incident asthma after adjustment for age, sex, race, smoking status, BMI, qualification, and Townsend deprivation index. Conclusions: Collectively, the study showed light-to-moderate coffee and tea consumption was associated with a reduced risk of adult-onset asthma and controlling total caffeine intake from coffee and tea for a moderate caffeine dose of 160.0 to 305.0 mg/day may be protective against adult-onset asthma. Further investigation on the possible preventive role of caffeine in asthma is warranted.


Asunto(s)
Asma , Café , Adulto , Anciano , Asma/epidemiología , Asma/etiología , Asma/prevención & control , Bancos de Muestras Biológicas , Cafeína , Humanos , Persona de Mediana Edad , Estudios Prospectivos , Factores de Riesgo , , Reino Unido/epidemiología
13.
Front Nutr ; 9: 954768, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36034921

RESUMEN

Background: Vitamin D has been known to be associated with asthma. However, the association between vitamin D status and asthma, lung function as well as hospitalization among adults remains unclear. Objective: To investigate the role of serum vitamin D in asthma prevalence, lung function, and asthma control in adults. Methods: Multivariable logistic regression was applied to assess the relationship between serum vitamin D and asthma prevalence, lung function (FEV1, FVC, and FEV1/FVC), current wheeze, and asthma-linked hospitalizations in a cross-sectional study of 435,040 adults aged 37-73 years old from the UK Biobank. Results: Compared to vitamin D deficiency, the odds of asthma were decreased by 6.4% [adjusted odds ratio (aOR) = 0.936; 95% CI: 0.911-0.962; p < 0.001] and 9.8% (aOR = 0. 0.902; 95% CI: 0.877-0. 0.927; p < 0.001) in individuals with insufficient and optimal vitamin D concentration, respectively, in the fully adjusted model. In total asthmatic patients, serum vitamin D was obviously and positively related with FEV1 (ß = 1.328 ml, 95% CI = 0.575-2.080), FVC (ß = 2.018 ml, 95% CI = 1.127-2.908), and FEV1/FVC (ß = 0.006%, 95% CI = 0.002-0.010). Asthmatic patients whose vitamin D level was in the deficient category had 9.3-19.9% higher odds of current wheeze than insufficient categories (aOR = 0.907; 95% CI: 0.861-0.957; p < 0.001) and optimal categories (aOR = 0.801; 95% CI: 0.759-0.845; p < 0.001), but the relationship between vitamin D and asthma hospitalization was not significant. Conclusion: Vitamin D deficiency was related to higher odds of asthma and current wheeze, and lower lung function in a large sample size study of British adults. Our results indicate a potential positive impact of serum vitamin D on asthma occurrence and disease control in adults.

14.
Front Med (Lausanne) ; 9: 841674, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35492344

RESUMEN

Objective: Talaromyces marneffei (TM) is an opportunistic fungus that is predominantly prevalent among patients who are HIV-positive in South-East Asia. However, few studies focused on the clinical features, laboratory findings, and prognosis across varying immune states. Methods: A total of 54 patients with TM infection in Xiangya Hospital of Central South University from January 1, 2006 to October 31, 2021 were retrospectively analyzed. Clinical profiles were compared across the different immune statuses by HIV-positive (HIV group, n = 18), HIV negative but with immunocompromised conditions (Non-HIV with IC Group, n = 11), and immunocompetent patients (n = 25). Results: All the patients were diagnosed by pathogen culture or by metagenomic next-generation sequencing (mNGS). The median age was 50, and patients with HIV were much younger compared to the other two groups. The most common symptom at presentation was fever (79.6%), followed by cough (70.4%), weight loss (61.1%), and expectoration (53.7%). The patients with HIV were more likely to develop into a subtype of disseminated TM affecting multiple organs including lymph node, liver, skin, and spleen, thus, resulting in higher hospital mortality compared to the other two groups. Patients without HIV but with immunocompromised conditions presented similar hospital mortality rates compared to immunocompetent patients, while experiencing longer days of hospitalization to recover from the diseases. Additionally, in this study, the pathogen culture easily confirmed the patients with HIV. However, mNGS presented as a promising tool to confirm TM infection in those suspicious patients without HIV. Conclusions: In summary, patients with HIV were more likely to develop into disseminated TM, resulting in higher mortality compared to those patients without HIV. Additionally, mNGS presented as an important supplementary tool to confirm TM infection in patients without HIV, particularly in those with immunocompromised diseases.

15.
Opt Lett ; 40(20): 4587-90, 2015 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-26469570

RESUMEN

A system has been developed in which multi-exposure laser speckle contrast imaging (LSCI) is implemented using a high frame rate CMOS imaging sensor chip. Processing is performed using a field programmable gate array (FPGA). The system allows different exposure times to be simulated by accumulating a number of short exposures. This has the advantage that the image acquisition time is limited by the maximum exposure time and that regulation of the illuminating light level is not required. This high frame rate camera has also been deployed to implement laser Doppler blood flow processing, enabling a direct comparison of multi-exposure laser speckle imaging and laser Doppler imaging (LDI) to be carried out using the same experimental data. Results from a rotating diffuser indicate that both multi-exposure LSCI and LDI provide a linear response to changes in velocity. This cannot be obtained using single-exposure LSCI, unless an appropriate model is used for correcting the response.


Asunto(s)
Rayos Láser , Imagen Óptica/instrumentación , Rotación
16.
Talanta ; 128: 117-24, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25059138

RESUMEN

Many important considerations in the design of practical Surface enhanced Raman spectroscopy (SERS) substrates are necessary, such as the low cost, simple preparation, mass production and high efficiency of sample collection, which the conventional rigid substrates are lack of. In this work, practical SERS substrates based on deposition of silver nanoparticles (Ag NPs) on commercially available low-cost filter paper were prepared by simple silver mirror reaction in a large scale, and utilized for rapid, portable and accurate identification and detection of pesticide residues at various peels. Compared with conventional substrates, this novel SERS substrate dramatically enhanced the sample collection efficiency by simply swabbing paper-based device across different surfaces without destroying the sample, meanwhile avoiding the substrate signal of real-world samples. Considering their low cost, portability, simplicity and high sample collection efficiency, Ag NP-decorated filter paper, as practical SERS substrate, are used in solving critical problems for detection of pesticide residues at various peels. SERS experiments were carried out on Ag NP-decorated filter paper combined with 'dynamic SERS' (D-SERS) due to its high detection sensitivity. The excellent detection performance of the Ag NP-based filter paper was demonstrated by detection thiram and paraoxon residues at various peels. Besides, the stability and reproducibility of the practical substrates were also involved.


Asunto(s)
Frutas , Papel , Residuos de Plaguicidas/análisis , Espectrometría Raman/métodos , Filtración/instrumentación , Nanopartículas del Metal/química , Nanopartículas del Metal/ultraestructura , Microscopía Electrónica de Rastreo , Modelos Químicos , Estructura Molecular , Paraoxon/análisis , Paraoxon/química , Residuos de Plaguicidas/química , Espectroscopía de Fotoelectrones , Reproducibilidad de los Resultados , Plata/química , Propiedades de Superficie , Tiram/análisis , Tiram/química
17.
Chem Biodivers ; 11(6): 982-6, 2014 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-24934684

RESUMEN

Phytochemical investigation of the AcOEt extract of G. Lucidum has led to the isolation of two new triterpenoids, 1 and 2, together with five known ones, 3-7. The structures of the new compounds were identified as 12ß-acetoxy-3ß,7ß-dihydroxy-11,15,23-trioxolanost-8-en-26-oic acid butyl ester (1) and 12ß-acetoxy-3,7,11,15,23-pentaoxolanost-8-en-26-oic acid butyl ester (2) on the basis of detailed spectroscopic analysis (mass spectrometry, and 1D- and 2D-NMR experiments). The antimicrobial activities of 1 and 2 were also evaluated.


Asunto(s)
Antibacterianos/farmacología , Bacillus/efectos de los fármacos , Cuerpos Fructíferos de los Hongos/química , Reishi/química , Staphylococcus aureus/efectos de los fármacos , Triterpenos/farmacología , Antibacterianos/química , Antibacterianos/aislamiento & purificación , Relación Dosis-Respuesta a Droga , Pruebas de Sensibilidad Microbiana , Conformación Molecular , Relación Estructura-Actividad , Triterpenos/química , Triterpenos/aislamiento & purificación
18.
Sensors (Basel) ; 13(9): 12632-47, 2013 Sep 18.
Artículo en Inglés | MEDLINE | ID: mdl-24051525

RESUMEN

The first fully integrated 2D CMOS imaging sensor with on-chip signal processing for applications in laser Doppler blood flow (LDBF) imaging has been designed and tested. To obtain a space efficient design over 64 × 64 pixels means that standard processing electronics used off-chip cannot be implemented. Therefore the analog signal processing at each pixel is a tailored design for LDBF signals with balanced optimization for signal-to-noise ratio and silicon area. This custom made sensor offers key advantages over conventional sensors, viz. the analog signal processing at the pixel level carries out signal normalization; the AC amplification in combination with an anti-aliasing filter allows analog-to-digital conversion with a low number of bits; low resource implementation of the digital processor enables on-chip processing and the data bottleneck that exists between the detector and processing electronics has been overcome. The sensor demonstrates good agreement with simulation at each design stage. The measured optical performance of the sensor is demonstrated using modulated light signals and in vivo blood flow experiments. Images showing blood flow changes with arterial occlusion and an inflammatory response to a histamine skin-prick demonstrate that the sensor array is capable of detecting blood flow signals from tissue.


Asunto(s)
Velocidad del Flujo Sanguíneo/fisiología , Determinación del Volumen Sanguíneo/instrumentación , Flujometría por Láser-Doppler/instrumentación , Semiconductores , Procesamiento de Señales Asistido por Computador/instrumentación , Transductores , Diseño de Equipo , Análisis de Falla de Equipo , Humanos , Reproducibilidad de los Resultados , Sensibilidad y Especificidad
19.
Med Eng Phys ; 33(6): 720-9, 2011 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-21316289

RESUMEN

The emergence of full field laser Doppler blood flow imaging systems based on CMOS camera technology means that a large amount of data from each pixel in the image needs to be processed rapidly and system resources need to be used efficiently. Conventional processing algorithms that are utilized in single point or scanning systems are therefore not an ideal solution as they will consume too much system resource. Two processing algorithms that address this problem are described and efficiently implemented in a field programmable gate array. The algorithms are simple enough to use low system resource but effective enough to produce accurate flow measurements. This enables the processing unit to be integrated entirely in an embedded system, such as in an application-specific integrated circuit. The first algorithm uses a short Fourier transformation length (typically 8) but averages the output multiple times (typically 128). The second method utilizes an infinite impulse response filter with a low number of filter coefficients that operates in the time domain and has a frequency-weighted response. The algorithms compare favorably with the reference standard 1024 point fast Fourier transform in terms of both resource usage and accuracy. The number of data words per pixel that need to be stored for the algorithms is 1024 for the reference standard, 8 for the short length Fourier transform algorithm and 5 for the algorithm based on the infinite impulse response filter. Compared to the reference standard the error in the flow calculation is 1.3% for the short length Fourier transform algorithm and 0.7% for the algorithm based on the infinite impulse response filter.


Asunto(s)
Procesamiento de Imagen Asistido por Computador/métodos , Flujometría por Láser-Doppler/métodos , Algoritmos , Velocidad del Flujo Sanguíneo/fisiología , Análisis de Fourier , Hemodinámica , Humanos , Procesamiento de Imagen Asistido por Computador/instrumentación , Procesamiento de Imagen Asistido por Computador/normas , Flujometría por Láser-Doppler/instrumentación , Flujometría por Láser-Doppler/normas , Reproducibilidad de los Resultados , Sensibilidad y Especificidad
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...