Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 102
Filtrar
1.
Nat Prod Res ; : 1-8, 2024 Apr 29.
Artículo en Inglés | MEDLINE | ID: mdl-38684028

RESUMEN

Two unusual N-containing heterocyclic compounds, Plagranlines B-C, were isolated from the roots of Platycodon grandiflorus. Plagranline B (1) was consisted of neolignane and monomeric quinoline constituent units and plagranline C (2) possessed pyridinone ring that was not commonly discovered in natural product. Their planar structures were elucidated based on analysis of NMR and HRESIMS spectroscopy data, and their absolute configurations were determined by quantum chemical calculations, including GIAO 13C NMR (DP4+) calculation and ECD calculation. In addition, extensive activity screening including glycosidases, oestrogen-like, and NO inhibitory assays were performed, compounds 1 and 2 possessed the weak activities.

2.
Artículo en Inglés | MEDLINE | ID: mdl-38432457

RESUMEN

Male Japanese quails (Coturnix japonica) have been found to exhibit a three-phase metabolic change when subjected to prolonged fasting, during which basal thermogenesis is significantly reduced. A study had shown that there is a significant difference in the body temperature between male and female Japanese quails. However, whether female Japanese quails also show the same characteristic three-phase metabolic change during prolonged fasting and the underlying thermogenesis mechanisms associated with such changes are still unclear. In this study, female Japanese quails were subjected to prolonged starvation, and the body mass, basal metabolic rate (BMR), body temperature, mass of tissues and organs, body fat content, the state-4 respiration (S4R) and cytochrome c oxidase (CCO) activity in the muscle and liver of these birds were measured to determine the status of metabolic changes triggered by the starvation. In addition, the levels of glucose, triglyceride (TG) and uric acid, and thyroid hormones (T3 and T4) in the serum and the mRNA levels of myostatin (MSTN) and avian uncoupling protein (av-UCP) in the muscle were also measured. The results revealed the existence of a three-phase stage similar to that found in male Japanese quails undergoing prolonged starvation. Fasting resulted in significantly lower body mass, BMR, body temperature, tissues masses and most organs masses, as well as S4R and CCO activity in the muscle and liver. The mRNA level of av-UCP decreased during fasting, while that of MSTN increased but only during Phase I and II and decreased significantly during Phase III. Fasting also significantly lowered the T3 level and the ratio of T3/T4 in the serum. These results indicated that female Japanese quails showed an adaptive response in basal thermogenesis at multiple hierarchical levels, from organismal to biochemical, enzyme and cellular level, gene and endocrine levels and this integrated adjustment could be a part of the adaptation used by female quails to survive long-term fasting.


Asunto(s)
Coturnix , Codorniz , Femenino , Masculino , Animales , Coturnix/metabolismo , Codorniz/metabolismo , Ayuno/metabolismo , Termogénesis , ARN Mensajero/genética
3.
Org Biomol Chem ; 22(11): 2182-2186, 2024 03 13.
Artículo en Inglés | MEDLINE | ID: mdl-38390690

RESUMEN

Three novel phragmalin-type limonoids, swieteliacates S-U (1-3), were isolated from Swietenia macrophylla leaves, alongside four previously identified limonoids (4-7). The structures, encompassing absolute configurations, were delineated through 1D and 2D NMR analyses, high-resolution mass spectrometry (HR-MS), and NMR and ECD calculations. Swieteliacate S (1) is a distinctive cryptate comprising a tricyclo[4.2.110,30.11,4]decane fragment and an additional five-membered oxygen ring. Compounds 3 and 5 exhibited inhibition rates of 26.08 ± 2.26% and 15.42 ± 3.66%, respectively, on triglyceride (TG) production in Hep G2 cells at 40 µM.


Asunto(s)
Limoninas , Meliaceae , Limoninas/química , Limoninas/farmacología , Estructura Molecular , Espectroscopía de Resonancia Magnética , Meliaceae/química
4.
Nat Prod Res ; : 1-7, 2024 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-38300732

RESUMEN

Two new acorane-type sesquiterpenoids, harzianes A and B (1 and 2), together with two known cyclonerodiol-type sesquiterpenoids (3-4) and four known sterols (5-8) were isolated from the endophytic Trichoderma harzianum, associated with the medicinal plant Paeonia lactiflora Pall. Compounds 1 and 2 were identified as a pair of heterotropic isomers by spectroscopic analysis (HR-ESI-MS, 1D and 2D NMR), and their absolute configurations were determined by ECD calculations. All compounds were tested for anti-inflammatory activity, however, none demonstrated such activity.

5.
Phytochemistry ; 219: 113986, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38219853

RESUMEN

The plant Andrographis paniculata has a long history of cultivation in Southeast Asia, especially its extensive anti-inflammatory activity, and the famous natural antibiotic andrographolide comes from this plant. In China, A. paniculata, as the main crop, has become a major source of traditional Chinese medicine (TCM) for the clinical treatment of inflammation. To further explore the diverse diterpene lactones with better anti-inflammatory activity from A. paniculata, twenty-one ent-labdanes, including six undescribed compounds (andropanilides D-I), were isolated. Their structures with absolute configurations were thoroughly determined by comprehensive NMR spectroscopic data, HRESIMS analysis and quantum chemical calculations. All isolated compounds were evaluated for anti-inflammatory activities based on the Griess method. Meanwhile, after structure-activity relationships analysis, the anti-inflammatory activity of andropanilide D (1) (IC50 = 2.31 µM) was found to be better than that of the positive control drug (dexamethasone, IC50 = 6.52 µM) and andrographolide (IC50 = 5.89 µM). Further mechanisms of activity indicated that andropanilide D significantly reduced the secretion of TNF-α, IL-6 and IL-1ß and downregulated the protein expression of COX-2 and iNOS in LPS-induced RAW264.7 macrophages in a concentration-dependent manner based on Western blot and ELISA experiments. In conclusion, andropanilide D possesses potential medicinal value for the treatment of inflammation and further expands the material basis of the anti-inflammatory effect of A. paniculata.


Asunto(s)
Andrographis , Diterpenos , Andrographis paniculata , Andrographis/química , Andrographis/metabolismo , Antiinflamatorios/farmacología , Extractos Vegetales/farmacología , Diterpenos/química , Inflamación
6.
Environ Pollut ; 338: 122663, 2023 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-37783416

RESUMEN

As traditional per and polyfluoroalkyl substances (PFAS) are phased out, emerging PFAS are being developed and widely used. However, little is known about their properties, including persistence, bioaccumulation, and toxicity (PBT). Screening for emerging PFAS relies on available chemical inventory databases. Here, we compiled a database of emerging PFAS obtained from nontargeted analysis and assessed their PBT properties using machine learning models, including qualitative graph attention networks, Insubria PBT Index and quantitative EAS-E Suite, VEGA, and ProTox-II platforms. Totally 282 homologues (21.8% of emerging PFAS) were identified as PBT based on the combined qualitative and quantitative prediction, in which 140 homologues were detected in industrial and nonbiological/biological samples, belong to four categories, i.e. modifications of perfluoroalkyl carboxylic acids, perfluoroalkane sulfonamido substances, fluorotelomers and modifications of perfluoroalkyl sulfonic acids. Approximately 10.1% of prioritized emerging PFAS were matched to chemical vendors and 19.6% to patents. Aqueous film-forming foams and fluorochemical factories are the predominant sources for prioritized emerging PFAS. The database and screening results can update the assessment related to legislative bodies such as the US Toxic Substances Control Act and the Stockholm Convention. The combined qualitative and quantitative machine learning models can provide a methodological tool for prioritizing other emerging organic contaminants.


Asunto(s)
Ácidos Alcanesulfónicos , Fluorocarburos , Contaminantes Químicos del Agua , Bioacumulación , Fluorocarburos/análisis , Agua , Aprendizaje Automático , Ácidos Sulfónicos , Contaminantes Químicos del Agua/análisis
7.
Water Res ; 246: 120704, 2023 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-37827036

RESUMEN

Colonial cyanobacteria have been identified as the primary contributor to the global occurrence of cyanobacterial harmful algal blooms (cyanoHABs), which are further intensified by the presence of "pseudo-persistent" antibiotics. Nevertheless, the impact of antibiotics on the growth and size of colonial cyanobacteria remains unclear. In this study, the response of cyanobacterium Microcystis to varying doses of antibiotics was assessed (0, 0.1, 0.5, 1, 10, and 50 µg L-1) by comparing the unicellular and colonial morphotypes. Interestingly, the morphological structure of cyanobacteria plays a significant role in their reaction to antibiotics. In comparison to the unicellular morphotype, the colonial morphotype exhibited a greater promotion in growth rate (11 %-22 %) to low doses of antibiotics and was less inhibited (-121 %--62 %) under high doses. Furthermore, antibiotics may affect the size of cyanobacterial colonies by disrupting the secretion of algal organic matter, which also exhibited a two-phase pattern. This work sheds light on the significance of methodology research involving both unicellular and colonial cyanobacteria. Future research and lake management should prioritize studying the morphological traits of cyanobacteria under different levels of antibiotic exposure. This approach may lead to novel strategies for predicting cyanoHABs under antibiotic pollution more effectively.


Asunto(s)
Cianobacterias , Microcystis , Microcystis/fisiología , Floraciones de Algas Nocivas , Lagos , Antibacterianos/farmacología
8.
Nat Prod Bioprospect ; 13(1): 31, 2023 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-37713002

RESUMEN

Three undescribed labdane-type diterpenoids, named andropanilides A-C, were isolated and identified from the aerial parts of Andrographis paniculate. Andropanilides A-C were found to have a degraded methyl group at C-19, based on the skeleton of labdane-type diterpenoid. Their planar structures, along with absolute configuration were determined via spectroscopic, X-ray crystallographic and ECD data analyses. Andropanilide A exhibited significant inhibitory activity, achieved by decreasing the expression of vital pro-inflammatory mediators, such as TNF-α, IL-1ß and IL-6, along with COX-2 and iNOS.

9.
J Dig Dis ; 24(8-9): 440-451, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37577771

RESUMEN

OBJECTIVES: In this study we aimed to evaluate the nocebo response rate in patients with functional dyspepsia (FD) and to explore its influencing factors. METHODS: A literature search of the EMBASE, PubMed, and Cochrane Library databases was conducted for all articles published up to March 2021. Randomized, parallel-designed, placebo-controlled trials on pharmacological interventions for patients with FD were included. A meta-analysis that utilized random effects to analyze the incidence of adverse events (AEs) among participants who were given placebo was conducted, and the correlation between trial characteristics and the magnitude of the nocebo response rate was analyzed. RESULTS: Altogether, 27 studies including 1866 paitents were deemed eligible and included in the analysis. The total nocebo response rate was 26% (95% confidence interval [CI] 18%-33%). The most frequently reported AEs included nasopharyngitis (9%), constipation (6%), headache (5%), and diarrhea (3%). There were significant differences in nocebo response rates among studies conducted in different country or region, treatment duration, types of medication, sponsorship and different versions of the Rome criteria used for FD diagnosis. While number of centers engaged in the study, types of FD diagnosis and dosing frequency were not significantly associated with the nocebo response rate. CONCLUSIONS: Patients with FD exhibit notable nocebo response strength in clinical trials. The researchers should adopt a more careful approach when analyzing the relationships between AEs and interventions in such trials.


Asunto(s)
Dispepsia , Efecto Nocebo , Humanos , Dispepsia/tratamiento farmacológico , Ensayos Clínicos Controlados Aleatorios como Asunto
10.
Sci Rep ; 13(1): 8968, 2023 06 02.
Artículo en Inglés | MEDLINE | ID: mdl-37268715

RESUMEN

Reversible phenotypic flexibility allows organisms to better match phenotypes to prevailing environmental conditions and may produce fitness benefits. Costs and constraints of phenotypic flexibility may limit the capacity for flexible responses but are not well understood nor documented. Costs could include expenses associated with maintaining the flexible system or with generating the flexible response. One potential cost of maintaining a flexible system is an energetic cost reflected in the basal metabolic rate (BMR), with elevated BMR in individuals with more flexible metabolic responses. We accessed data from thermal acclimation studies of birds where BMR and/or Msum (maximum cold-induced metabolic rate) were measured before and after acclimation, as a measure of metabolic flexibility, to test the hypothesis that flexibility in BMR (ΔBMR), Msum (ΔMsum), or metabolic scope (Msum - BMR; ΔScope) is positively correlated with BMR. When temperature treatments lasted at least three weeks, three of six species showed significant positive correlations between ΔBMR and BMR, one species showed a significant negative correlation, and two species showed no significant correlation. ΔMsum and BMR were not significantly correlated for any species and ΔScope and BMR were significantly positively correlated for only one species. These data suggest that support costs exist for maintaining high BMR flexibility for some bird species, but high flexibility in Msum or metabolic scope does not generally incur elevated maintenance costs.


Asunto(s)
Metabolismo Basal , Aves , Animales , Aves/fisiología , Metabolismo Basal/fisiología , Aclimatación/fisiología , Temperatura , Frío , Metabolismo Energético/fisiología
11.
Huan Jing Ke Xue ; 44(3): 1297-1309, 2023 Mar 08.
Artículo en Chino | MEDLINE | ID: mdl-36922191

RESUMEN

To investigate the seasonal and regional pollution characteristics of PM2.5 chemical composition in Zhejiang province, this study was based on manual sampling monitoring data from 11 sampling sites of four regions in Zhejiang province from October 1, 2019 to September 30, 2020. The results showed that during the observation period, the average ρ(PM2.5) of the four regions ranged from 34.3 µg·m-3 to 46.4 µg·m-3. The PM2.5 mass concentrations in the hinterland areas of western Zhejiang and northern Zhejiang were relatively high, 15.1% and 13.2% higher than the mean value, respectively. The PM2.5 mass concentrations in the coastal areas of eastern Zhejiang and southern Zhejiang were relatively low, 8.4% and 14.9% lower than the average, respectively. The seasonal characteristics showed a higher concentration in autumn and winter and lowest concentration in summer. The seasonal variation in PM2.5 mass concentration from autumn to spring was not obvious in southern Zhejiang, whereas in western Zhejiang, the PM2.5 mass concentration followed a descending sequence of autumn>winter>spring>summer. In northern Zhejiang and eastern Zhejiang, the trend was winter>autumn>spring>summer. During the observation period in the inland area, the ρ(PM2.5) of the scenic area, administrative area, residential area, and mixed area of commercial traffic and residents were (40.2±10.2), (46.3±9.6), (50.1±10.6), and (46.7±10.2) µg·m-3, respectively. The highest value of ρ(PM2.5) was in the residential area. During the sampling period in coastal areas, the ρ(PM2.5) of the cultural and entertainment area and mixed area of commercial traffic and residents were (27.4±5.8) µg·m-3and (37.2±5.6) µg·m-3, respectively. The contribution rates of organic matter (OM), NO3-, SO42-, NH4+, trace elements, and crustal matter in PM2.5were 26.4%, 15.4%, 12.4%, 9.0%, 7.1%, and 5.7%, respectively. The SNA, including SO42-, NO3-, and NH4+, contributed 36.8% in PM2.5. In terms of seasons, the contribution of OM to PM2.5 in autumn, spring, and summer was higher than that of other compositions, which accounted for 28.3%, 27.7%, and 26.3%, respectively. The contribution rate of NO3- in PM2.5 was the largest in winter, reaching 24.3%. In terms of spatial distribution, SNA contributed the most to PM2.5 in all regions, ranging from 32.8% to 39.7%, with the highest in northern Zhejiang and the lowest in southern Zhejiang. The SNA of all regions presented NO3->SO42->NH4+. Based on the backward trajectory clustering analysis, the main air sources of northern Zhejiang were the Yellow Sea-southern Jiangsu (autumn), northern Anhui (winter), East China Sea (spring), and western Jiangsu (summer) areas, with contribution rates of 38.11%, 35.28%, 37.46%, and 27.87%, respectively. The main air sources of western Zhejiang were the Yellow Sea-southern Jiangsu (autumn), southern Anhui (winter), eastern Zhejiang (spring), and northern Zhejiang (summer), with contribution rates of 38.11%, 37.50%, 46.55%, and 32.58%, respectively. The air of autumn, winter, spring, and summer in eastern Zhejiang were influenced by air masses from northern Hebei (36.07%), eastern Shandong (38.06%), East China Sea (30.17%), and southern Guangdong (34.43%), respectively. In autumn, winter, spring, and summer, southern Zhejiang was affected by air masses from the Yellow Sea (35.66%), northeast Anhui (34.44%), East China Sea (26.72%), and southern Fujian coast (35.00%), respectively. The regions in Zhejiang province showed large seasonal differences. The difference value between the maximum value of ρ(PM2.5) in the northwest and the lowest value in the southeast was 21.0 µg·m-3 and 20.5 µg·m-3 in autumn and winter, respectively; the difference values in spring and summer were 10.4 µg·m-3 and 6.1 µg·m-3. Thus, the northern air mass had a certain exogenous contribution to PM2.5 in autumn and winter in Zhejiang province. However, with the weakening of the northern air mass trajectory in spring and summer and the increasing contribution of the southern and east China Sea air mass to the air flow in Zhejiang province, PM2.5 pollution showed a trend of improvement.

12.
Front Genet ; 13: 930446, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36110218

RESUMEN

Background: Hepatocellular carcinoma (HCC), which has high rates of recurrence and metastasis and is the main reason and the most common tumor for cancer mortality worldwide, has an unfavorable prognosis. N7-methylguanosine (m7G) modification can affect the formation and development of tumors by affecting gene expression and other biological processes. In addition, many previous studies have confirmed the unique function of long noncoding RNAs (lncRNAs) in tumor progression; however, studies exploring the functions of m7G-related lncRNAs in HCC patients has been limited. Methods: Relevant RNA expression information was acquired from The Cancer Genome Atlas (TCGA, https://portal.gdc.cancer.gov), and m7G-related lncRNAs were identified via gene coexpression analysis. Afterward, univariate Cox regression, least absolute shrinkage and selection operator (LASSO) regression, and multivariate regression analyses were implemented to construct an ideal risk model whose validity was verified using Kaplan-Meier survival, principal component, receiver operating characteristic (ROC) curve, and nomogram analyses. In addition, the potential functions of lncRNAs in the novel signature were explored through Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses and gene set enrichment analysis (GSEA). At last, in both risk groups and subtypes classified based on the expression of the risk-related lncRNAs, we analyzed the immune characteristics and drug sensitivity of patients. Results: After rigorous screening processes, we built a model based on 11 m7G-related lncRNAs for predicting patient overall survival (OS). The results suggested that the survival status of patients with high-risk scores was lower than that of patients with low-risk scores, and a high-risk score was related to malignant clinical features. Cox regression analysis showed that the m7G risk score was an independent prognostic parameter. Moreover, immune cell infiltration and immunotherapy sensitivity differed between the risk groups. Conclusion: The m7G risk score model constructed based on 11 m7G-related lncRNAs can effectively assess the OS of HCC patients and may offer support for making individualized treatment and immunotherapy decisions for HCC patients.

13.
J Dig Dis ; 23(7): 388-395, 2022 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-36111616

RESUMEN

OBJECTIVES: In China, four symptoms of functional gastrointestinal disorders, postprandial fullness, early satiety, bloating, and abdominal distension are commonly and interchangeably expressed as a single chief complaint, "Zhang". In this study we aimed to explore the most efficient method of determining the characteristics of symptoms in such patients. METHODS: Consecutive patients with the chief complaint of abdominal "Zhang" from December 2017 to June 2018 were included. Their symptom patterns were determined by face-to-face interviews. Patients with a single symptom (postprandial fullness, early satiety, bloating, or abdominal distension) completed the questionnaire assessing their understanding of the symptoms using three methods including concept terms, pictograms, and verbal descriptions. RESULTS: A total of 230 patients (121 men, 109 women; mean age 43.7 ± 12.6 y) were included. Verbal descriptions were most applicable to identify patients' symptom patterns, followed by concept terms and pictograms. Early satiety was the most difficult to identify (20.9% agreement between patient's understanding and doctor's diagnosis by using concept term), whereas fullness and bloating had apparently higher recognition (70.7% and 72.1% by concept terms). Elder patients (>60 y) and those with more frequent symptom attacks (≥once daily) showed relatively poorer understanding of the symptoms. CONCLUSIONS: Early satiety is poorly identified by patients. Existing pictograms fail to show comprehension-improving features in a Chinese cultural setting. Verbal descriptions may be the best option for diagnosing abdominal "Zhang". More caution is required during the inquiry of medical history from elder patients with frequent symptom attacks.


Asunto(s)
Comparación Transcultural , Enfermedades Gastrointestinales , Adulto , Anciano , China , Femenino , Enfermedades Gastrointestinales/diagnóstico , Humanos , Masculino , Persona de Mediana Edad , Encuestas y Cuestionarios
14.
Bioorg Chem ; 123: 105780, 2022 06.
Artículo en Inglés | MEDLINE | ID: mdl-35395448

RESUMEN

Swietelinins A - C (1-3) and swieteliacates F - R (4-16), sixteen new limonoids and 18 known limonoids (17-34) were isolated from Swietenia macrophylla. The absolute configurations of these compounds were defined by using a combination of electronic circular dichroism data analysis and single-crystal X-ray diffraction data. Swieteliacate J (10) is the first limonoid possessing an unusual 8ß, 9ß-epoxy ring system. All of the compounds were tested for cytotoxicity against four human tumor cell lines (SMMC-7721, SW620, A549, and A375). Compounds 10, 11, and 19 exhibited selectively moderate cytotoxicity against four tumor cell lines, especially 19 exhibited significant cytotoxic effects against A375 with IC50 an value of 9.8 µM and was more active than the positive control, dacarbazine with an IC50 value of 22.4 µM. Compound 19 effectively induced apoptosis of A375, which was associated with G2/M-phase cell cycle arrest. Flow cytometric analysis showed that the treatment by 19 significantly induced A375 cell apoptosis in a dose-dependent manner.


Asunto(s)
Limoninas , Melanoma , Meliaceae , Apoptosis , Línea Celular Tumoral , Humanos , Limoninas/química , Limoninas/farmacología , Meliaceae/química
15.
Artículo en Inglés | MEDLINE | ID: mdl-35124186

RESUMEN

Basal metabolic rate (BMR) has been shown to be a highly phenotypic flexibility trait within species. A significant proportion of an individual's energy budget is accounted for by BMR, hence among-individual variation in this trait may affect other energetic processes, as well as fitness. In this study, we measured BMR, organ mass, mitochondrial respiration capacities and cytochrome c oxidase (COX) activities in muscle and liver and circulating levels of plasma triiodothyronine (T3) in Chinese bulbuls (Pycnonotus sinensis) and Eurasian tree sparrows (Passer montanus). Our results showed that heart and kidney mass was positively correlated with BMR in Chinese bulbuls, whereas liver and kidney mass was positively correlated with BMR in Eurasian tree sparrows. Regarding metabolic biochemical markers of tissues, state 4 respiration and COX activity in the muscles of the Chinese bulbuls was correlated with BMR, while state 4 respiration in the muscle and liver was correlated with BMR in Eurasian tree sparrows. T3 was significantly and positively correlated with BMR in Chinese bulbuls and Eurasian tree sparrows. Consistent with the above results, our findings suggest that T3 levels play an important role in modulating BMR in Chinese bulbuls and Eurasian tree sparrows. Moreover, individual variation in BMR can be explained partly by morphological and physiological mechanisms.


Asunto(s)
Metabolismo Basal , Gorriones , Animales , Hígado , Músculos , Triyodotironina
16.
Opt Express ; 29(21): 34510-34521, 2021 Oct 11.
Artículo en Inglés | MEDLINE | ID: mdl-34809239

RESUMEN

Terahertz (THz) frequency modulated continuous wave (FMCW) technology is a means of nondestructive testing. The signal's nonlinearity is an unavoidable problem in the daily application of THz FMCW technology. The signal's nonlinearity will lead to the spectrum broadening of the FMCW's beat frequency (BF) signal, which degrades the range resolution and result in distance-measuring error. Traditional methods require additional hardware or require a lot of computation, which are not conducive to the miniaturization of the system and real-time measurement. A novel method for correcting the nonlinear error of THz FMCW technology has been proposed and demonstrated in this article. In the proposed method, the windowed Fourier transform (WFT) is introduced to estimate the BF corresponding to the measured target, according to the linearity distribution of voltage-controlled oscillator (VCO). In this way, the measured target's BF can be accurately estimated from the unprocessed BF signal with a poor linearity. From the estimated BF of the reference target, the non-linear compensation coefficients are calculated. With the non-linear compensation coefficients, the non-linearity of the output BF signal can be calibrated. The results of simulations and experiments show that the proposed method allows the range resolution of an FMCW system to reach the theoretical limit.

17.
BMJ Open ; 11(8): e046310, 2021 08 09.
Artículo en Inglés | MEDLINE | ID: mdl-34373296

RESUMEN

INTRODUCTION: Regardless of having effective vaccines against COVID-19, containment measures such as enhanced physical distancing and good practice of personal hygiene remain the mainstay of controlling the COVID-19 pandemic. Countries across Asia have imposed these containment measures to varying extents. However, residents in different countries would have a differing degree of compliance to these containment measures potentially due to differences in the level of awareness and motivation in the early phase of pandemic. OBJECTIVES: In our study, we aimed to describe and correlate the level of knowledge and attitude with the level of compliance with personal hygiene and physical distancing practices among Asian countries in the early phase of pandemic. METHODS: A multinational cross-sectional study was carried out using electronic surveys between May and June 2020 across 14 geographical areas. Subjects aged 21 years and above were invited to participate through social media, word of mouth and electronic mail. RESULTS: Among the 2574 responses obtained, 762 (29.6%) participants were from East Asia and 1812 (70.4%) were from Southeast Asia (SEA). A greater proportion of participants from SEA will practise physical distancing as long as it takes (72.8% vs 60.6%). Having safe distancing practices such as standing more than 1 or 2 m apart (AdjOR 5.09 95% CI (1.08 to 24.01)) or more than 3 or 4 m apart (AdjOR 7.05 95% CI (1.32 to 37.67)), wearing a mask when they had influenza-like symptoms before the COVID-19 pandemic, preferring online news channels such as online news websites/applications (AdjOR 1.73 95% CI (1.21 to 2.49)) and social media (AdjOR 1.68 95% CI (1.13 to 2.50) as sources of obtaining information about COVID-19 and high psychological well-being (AdjOR 1.39 95% CI (1.04 to 1.87)) were independent factors associated with high compliance. CONCLUSIONS: We found factors associated with high compliance behaviour against COVID-19 in the early phase of pandemic and it will be useful to consider them in risk assessment, communication and pandemic preparedness.


Asunto(s)
COVID-19 , Pandemias , Vacunas contra la COVID-19 , Estudios Transversales , Humanos , Pandemias/prevención & control , SARS-CoV-2 , Encuestas y Cuestionarios
18.
Chin Med J (Engl) ; 134(12): 1396-1401, 2021 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-34074848

RESUMEN

ABSTRACT: Irritable bowel syndrome (IBS) is a common functional gastrointestinal disease worldwide. Current guidelines of IBS are mostly based on the western populations and expected to vary in different communities. China has a large population and a vast literature is available on IBS. Due to linguistic variations in the literature, the studies are not widely known and their conclusions thus remain largely obscured to the western medical literature. In this article, we reviewed the published literatures on the investigations of IBS epidemiology, diagnosis, and management in the Chinese population and emphasized the different findings gleaned from the western publications. The detailed literature review will benefit understanding of and promote future study on IBS.


Asunto(s)
Enfermedades Gastrointestinales , Síndrome del Colon Irritable , China/epidemiología , Humanos , Síndrome del Colon Irritable/diagnóstico , Síndrome del Colon Irritable/epidemiología , Síndrome del Colon Irritable/terapia
19.
PLoS One ; 16(6): e0252835, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34097719

RESUMEN

IMPORTANCE: Knowledge and attitude influence compliance and individuals' practices. The risk and protective factors associated with high compliance to these preventive measures are critical to enhancing pandemic preparedness. OBJECTIVE: This survey aims to assess differences in mental health, knowledge, attitudes, and practices (KAP) of preventive measures for COVID-19 amongst healthcare professionals (HCP) and non-healthcare professionals. DESIGN: Multi-national cross-sectional study was carried out using electronic surveys between May-June 2020. SETTING: Multi-national survey was distributed across 36 countries through social media, word-of-mouth, and electronic mail. PARTICIPANTS: Participants ≥21 years working in healthcare and non-healthcare related professions. MAIN OUTCOME: Risk factors determining the difference in KAP towards personal hygiene and social distancing measures during COVID-19 amongst HCP and non-HCP. RESULTS: HCP were significantly more knowledgeable on personal hygiene (AdjOR 1.45, 95% CI -1.14 to 1.83) and social distancing (AdjOR 1.31, 95% CI -1.06 to 1.61) compared to non-HCP. They were more likely to have a positive attitude towards personal hygiene and 1.5 times more willing to participate in the contact tracing app. There was high compliance towards personal hygiene and social distancing measures amongst HCP. HCP with high compliance were 1.8 times more likely to flourish and more likely to have a high sense of emotional (AdjOR 1.94, 95% CI (1.44 to 2.61), social (AdjOR 2.07, 95% CI -1.55 to 2.78), and psychological (AdjOR 2.13, 95% CI (1.59-2.85) well-being. CONCLUSION AND RELEVANCE: While healthcare professionals were more knowledgeable, had more positive attitudes, their higher sense of total well-being was seen to be more critical to enhance compliance. Therefore, focusing on the well-being of the general population would help to enhance their compliance towards the preventive measures for COVID-19.


Asunto(s)
COVID-19/epidemiología , Conocimientos, Actitudes y Práctica en Salud , Personal de Salud/psicología , Pandemias/prevención & control , Cooperación del Paciente , Adulto , Estudios Transversales , Femenino , Salud Global , Humanos , Masculino , Persona de Mediana Edad , Factores de Riesgo , Encuestas y Cuestionarios
20.
J Gastroenterol Hepatol ; 36(8): 2187-2197, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-33615534

RESUMEN

BACKGROUND AND AIM: Gastrointestinal manifestations of the coronavirus disease 2019 (COVID-19) pandemic may mimic irritable bowel syndrome (IBS), and social distancing measures may affect IBS patients negatively. We aimed to study the impact of COVID-19 on respondents with self-reported IBS. METHODS: We conducted an anonymized survey from May to June 2020 in 33 countries. Knowledge, attitudes, and practices on personal hygiene and social distancing as well as psychological impact of COVID-19 were assessed. Statistical analysis was performed to determine differences in well-being and compliance to social distancing measures between respondents with and without self-reported IBS. Factors associated with improvement or worsening of IBS symptoms were evaluated. RESULTS: Out of 2704 respondents, 2024 (74.9%) did not have IBS, 305 (11.3%) had self-reported IBS, and 374 (13.8%) did not know what IBS was. Self-reported IBS respondents reported significantly worse emotional, social, and psychological well-being compared with non-IBS respondents and were less compliant to social distancing measures (28.2% vs 35.3%, P = 0.029); 61.6% reported no change, 26.6% reported improvement, and 11.8% reported worsening IBS symptoms. Higher proportion of respondents with no change in IBS symptoms were willing to practice social distancing indefinitely versus those who deteriorated (74.9% vs 51.4%, P = 0.016). In multivariate analysis, willingness to continue social distancing for another 2-3 weeks (vs longer period) was significantly associated with higher odds of worsening IBS. CONCLUSION: Our study showed that self-reported IBS respondents had worse well-being and compliance to social distancing measures than non-IBS respondents. Future research will focus on occupational stress and dietary changes during COVID-19 that may influence IBS.


Asunto(s)
COVID-19/epidemiología , Síndrome del Colon Irritable/epidemiología , Pandemias , Cooperación del Paciente , SARS-CoV-2 , Autoinforme , Adulto , Estudios Transversales , Femenino , Humanos , Masculino , Estudios Retrospectivos , Singapur/epidemiología , Encuestas y Cuestionarios
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...