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1.
J Environ Sci (China) ; 114: 297-307, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35459493

RESUMO

To investigate nitrous acid (HONO) levels and potential HONO sources above crop rotation fields. The HONO fluxes were measured by the aerodynamic gradient (AG) method from 14 December 2019 to 2 January 2020 over an agricultural field in the Huaihe River Basin. The ambient HONO levels were measured at two different heights (0.15 and 1.5 m), showing a typical diurnal cycle with low daytime levels and high nighttime levels. The upward HONO fluxes were mostly observed during the day, whereas deposition dominated at night. The diurnal variation of HONO flux followed solar radiation, with a noontime maximum of 0.2 nmol/(m2∙sec). The average upward HONO flux of 0.06 ± 0.17 nmol/(m2∙sec) indicated that the agricultural field was a net source for atmospheric HONO. The higher HONO/NO2 ratio and NO2-to-HONO conversion rate close to the surface suggested that nocturnal HONO was formed and released near the ground. The unknown HONO source was derived from the daytime HONO budget analysis, with an average strength of 0.31 ppbV/hr at noontime. The surface HONO flux, which was highly correlated with the photolysis frequency J(NO2) (R2 = 0.925) and the product of J(NO2) × NO2 (R2 = 0.840), accounted for ∼23% of unknown daytime HONO source. The significant correlation between HONO fluxes and J(NO2) suggests a light-driven HONO formation mechanism responsible for the surface HONO flux during daytime.


Assuntos
Dióxido de Nitrogênio , Rios , China , Dióxido de Nitrogênio/análise , Ácido Nitroso/análise , Fotólise
2.
Entropy (Basel) ; 23(9)2021 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-34573743

RESUMO

This study aimed to investigate consumers' visual image evaluation of wrist wearables based on Kansei engineering. A total of 8 representative samples were screened from 99 samples using the multidimensional scaling (MDS) method. Five groups of adjectives were identified to allow participants to express their visual impressions of wrist wearable devices through a questionnaire survey and factor analysis. The evaluation of eight samples using the five groups of adjectives was analyzed utilizing the triangle fuzzy theory. The results showed a relatively different evaluation of the eight samples in the groups of "fashionable and individual" and "rational and decent", but little distinction in the groups of "practical and durable", "modern and smart" and "convenient and multiple". Furthermore, wrist wearables with a shape close to a traditional watch dial (round), with a bezel and mechanical buttons (moderate complexity) and asymmetric forms received a higher evaluation. The acceptance of square- and elliptical-shaped wrist wearables was relatively low. Among the square- and rectangular-shaped wrist wearables, the greater the curvature of the chamfer, the higher the acceptance. Apparent contrast between the color of the screen and the casing had good acceptance. The influence of display size on consumer evaluations was relatively small. Similar results were obtained in the evaluation of preferences and willingness to purchase. The results of this study objectively and effectively reflect consumers' evaluation and potential demand for the visual images of wrist wearables and provide a reference for designers and industry professionals.

3.
Guang Pu Xue Yu Guang Pu Fen Xi ; 36(7): 2001-5, 2016 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-30035511

RESUMO

A new type of fiber coupling Long-Path Differential Optical Absorption Spectroscopy System(LP-DOAS) based on schmidt - cassegrain telescope was introduced in detail in this paper and it was applied to the accurate measurement of the actual atmospheric HONO and NO2. This measuring system simplified the structure of traditional LP-DOAS system, combining with the design of optical fiber coupling.It made full use of the telescope primary mirror's effective area. The effects of the offset, dark current and telescope stray light to the new LP-DOAS system were discussed in this paper; On a clear day, the ratio between telescope stray light and the optical intensities was less than 1%. To verify the accurate of the new LP-DOAS system, the atmospheric NO2 were simultaneously measured with the new LP-DOAS system and traditional LP-DOAS system. The correlation coefficient R2 was up to 0.968. The observation of atmospheric HONO was carried out by using the fiber coupling LP-DOAS in Gucheng, Hebei Province, China, and the detection limit (2σ) of HONO and NO2 was 84.2 and 144.6 ppt , respectively, with 2 490 m path length and the average time resolution of about 30 s. In the whole measurement in Gucheng, the maximum of HONO and NO2 were 3.2 and 37.8 ppb, respectively, and the minimum were both under the detection limits; the ratio of HONO/NO2 at night was calculated.

4.
Guang Pu Xue Yu Guang Pu Fen Xi ; 36(6): 1936-40, 2016 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-30053357

RESUMO

The self-developed portable DOAS instrument based on differential optical absorption spectroscopy(DOAS) and composed of optical fiber spectrograph and multiple-pass cell was introduced. The standard gases of SO2 and NO2 were employed to test the accuracy and stability of the system, and then cruise observation of SO2, NO2 and benzene was carried out using the system in Tongling industrial park. During the entire period, the polluted gases showed high concentrations near the contaminated areas and the maximum concentrations of SO2, NO2 and benzene were 5 023.2, 2 195.2 and 162.5 µg·m-3, respectively. With 12.6 m optical path, the detection limits of SO2, NO2 and benzene were 67.0, 169.9, 30.6 µg·m-3, respectively. The portable DOAS system provides a convenient and effective technique for industrial park about emergency and supervisory monitoring and evaluation of gas leakage and fugitive emissions of gaseous pollutants.

5.
Guang Pu Xue Yu Guang Pu Fen Xi ; 36(2): 466-70, 2016 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-27209751

RESUMO

As a highly sensitive detection technology, incoherent broadband cavity enhanced absorption spectroscopy (IBBCEAS) have successfully measured a variety of trace gases. According to the principle of cavity enhanced absorption spectroscopy, if the accurate concentration of the target gas, the curve of the mirror reflectance, effective absorption path length, the light intensity of the absorbing gas and non-absorbing gas are known, the absorption cross section of the absorption gas can be measured. The accurate measurements of absorption cross section are necessary for satellite retrievals of atmospheric trace gases and the atmospheric research. This paper describes an incoherent broadband cavity enhanced absorption spectroscopy(IBBCEAS) instrument with 365 nm LED as the light source for measuring absorption cross section of SO2 from 357 to 385 nm which is arising from the spin-forbidden a ³B1--X¹A1 transition. In comparison to the literature absorption cross section of SO2, and correlation coefficient r is 0.997 3. The result shows the potential of the IBBCEAS system for measuring weak absorption cross section.

6.
Sensors (Basel) ; 15(2): 3116-37, 2015 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-25647741

RESUMO

Aquatic debris monitoring is of great importance to human health, aquatic habitats and water transport. In this paper, we first introduce the prototype of an aquatic sensor node equipped with an embedded camera sensor. Based on this sensing platform, we propose a fast and accurate debris detection algorithm. Our method is specifically designed based on compressive sensing theory to give full consideration to the unique challenges in aquatic environments, such as waves, swaying reflections, and tight energy budget. To upload debris images, we use an efficient sparse recovery algorithm in which only a few linear measurements need to be transmitted for image reconstruction. Besides, we implement the host software and test the debris detection algorithm on realistically deployed aquatic sensor nodes. The experimental results demonstrate that our approach is reliable and feasible for debris detection using camera sensors in aquatic environments.

7.
Org Biomol Chem ; 12(19): 3062-70, 2014 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-24695783

RESUMO

A series of 2'-hydroxychalcone derivatives was synthesized and the effects of all the compounds on growth of A549 lung cancer cell were investigated. The results showed that all compounds had inhibitory effects on the growth of A549 lung cancer cells and compound possessed the highest growth inhibitory effect and induced autophagy of A549 lung cancer cells.


Assuntos
Autofagia/efeitos dos fármacos , Chalconas/farmacologia , Descoberta de Drogas , Neoplasias Pulmonares/patologia , Apoptose/efeitos dos fármacos , Western Blotting , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Forma Celular/efeitos dos fármacos , Chalconas/síntese química , Chalconas/química , Humanos , Concentração Inibidora 50 , L-Lactato Desidrogenase/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , Necrose
8.
Breast Cancer ; 2024 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-39117793

RESUMO

BACKGROUND: There have been concerns about the use of tumor necrosis factor inhibitors (TNFi) for autoimmune disease in patients with recently diagnosed cancer. We assessed the survival of patients with rheumatoid arthritis (RA) and newly diagnosed early breast cancer (BC) treated with TNFi in the first two years after BC diagnosis. METHODS: We identified patients in two datasets: (1) Optum's de-identified Clinformatics® Data Mart Database (CDM), (2) Surveillance, Epidemiology, and End Results program (SEER) and Texas Cancer Registry (TCR) Medicare-linked cohort. We grouped patients according to whether they received TNFi, conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) only, or no DMARDs within 2 years after BC. Outcomes were overall survival (OS) and BC-specific survival (BCSS). We conducted landmark analyses at years 1 and 2, with multivariable Cox regressions using propensity scores for adjustment. RESULTS: In the first year after BC, 165/970 (17.0%) and 201/1246 (16.1%) patients received TNFi in CDM and SEER/TCR-Medicare respectively. In the 1 year landmark, no significant differences in OS were observed between patients treated with TNFi and patients treated with csDMARDs only in CDM (hazard ratio [HR] = 0.77, 95% confidence interval [CI] 0.42-1.40) or SEER/TCR-Medicare (HR = 0.84, 95% CI 0.54-1.31). BCSS (SEER/TCR-Medicare) was better in patients receiving TNFi than in those receiving csDMARDs only (HR = 0.28, 95% CI 0.08-0.98). In CDM, glucocorticoid therapy had worse OS than those without glucocorticoids (HR = 2.18, 95% CI 1.13-4.18). This was also observed in SEER/TCR-Medicare (not statistically significant). Similar results were observed for the 2 year landmark. CONCLUSIONS: TNFi treatment during the first two years after early BC was not associated with worse survival.

9.
Sleep Med ; 111: 146-159, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37776585

RESUMO

STUDY OBJECTIVES: Increasing evidence suggests that napping is associated with cognitive impairment and dementia, but the conclusions are inconsistent. Moreover, the extent of the risk is uncertain. We therefore conducted a systematic review and meta-analysis to quantify the connection between napping and cognitive impairment. METHODS: We performed a systematic search of PubMed, EMBASE, Web of Science, and Cochrane Library for studies that were published up to June 2023, and assessed associations between napping and cognitive impairment. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated as the effect sizes for all studies. Heterogeneity and potential publication biases were assessed. RESULTS: A total of 4535 papers were retrieved, with 20 reports assessing the relationships between napping and cognitive impairment. Pooled analysis indicated that napping was associated with dementia (OR = 1.14; 95% CI: 1.07-1.21). Importantly, we found that those napping longer than 30, 45, and 60 min/day were 35%, 41%, and 40%, respectively, more likely to have an increased risk of cognitive impairment (30 min: OR = 1.35; 95% CI: 1.24-1.48; 45 min: OR = 1.41; 95% CI: 1.27-1.58; 60 min: OR = 1.40; 95% CI: 1.26-1.56). North America and Europe showed that associations existed between napping and cognitive impairment (North America: OR = 1.15; 95% CI: 1.04-1.27; Europe: OR = 1.13; 95% CI: 1.08-1.18). CONCLUSIONS: This meta-analysis indicated associations between long napping durations and cognitive impairment or dementia, suggesting that longer napping might be a potential risk factor of adverse cognitive outcomes.

10.
Front Public Health ; 11: 1297472, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38125844

RESUMO

Objective: This study analysed blood donation deferral trends, reasons and demographic/lifestyle characteristics among students in Huzhou City. The aim was to understand the health status of students and reduce the deferral rate. Methods: Data on blood donation deferral among students in Huzhou City from 2018 to 2022 were collected and analysed. Deferral trends and main reasons were investigated. Using demographic and lifestyle data from 2,619 cases in 2022, a risk prediction model for deferral was constructed. Results: The deferral rate among students in Huzhou City from 2018 to 2022 was 12.60% (p = 0.000, 95%CI: 12.14-13.06%), showing a significant increasing trend. Temporary deferral was the main reason, with alanine aminotransferase (ALT), blood pressure (BP) and haemoglobin (Hb) as the main deferral factors. ALT had a deferral rate of 5.23% (4.92-5.53%), BP 3.30% (3.06-3.55%), and Hb 2.92% (2.68-3.15%). Demographic and lifestyle characteristics in 2022 showed no significant differences between education level, household registration and deferral rate (p > 0.05). However, age, sex, blood donation history, sleep quality, diet and mental state had variable effects on ALT, BP, and Hb deferrals (p < 0.05). Logistic regression showed that sex, blood donation history, sleep quality, diet and mental status were independent risk factors for ALT deferral (p < 0.05), with odds ratios (ORs) of 5.057, 2.735, 1.594, 3.679, and 1.957, respectively. Age, blood donation history, sleep quality and mental state were independent risk factors for BP deferral (p < 0.05), with ORs of 0.256, 3.658, 6.042, and 1.812, respectively. Gender, blood donation history and diet were independent risk factors for Hb deferral (p < 0.05), with ORs of 0.244, 0.542, and 3.103, respectively. Conclusion: Students' health problems require attention. Effective health education should improve self-health management and pre-donation health behaviour to encourage regular blood donation.


Assuntos
Doação de Sangue , Doadores de Sangue , Humanos , Estudos Retrospectivos , Hemoglobinas/análise , Estudantes , Características da Família , Estilo de Vida
11.
Org Biomol Chem ; 10(43): 8640-4, 2012 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-23032577

RESUMO

We develop a pyrazoline-based fluorescent sensor for biological Zn(2+) detection. The sensor shows good binding selectivity for Zn(2+) over competing metal with 40-fold fluorescence enhancement in response to Zn(2+). The new probe is cell-permeable and can be used to detect intracellular zinc ions in living neuron cells.


Assuntos
Corantes Fluorescentes/química , Neurônios/química , Pirazóis/química , Zinco/análise , Animais , Corantes Fluorescentes/síntese química , Estrutura Molecular , Neurônios/citologia , Células PC12 , Pirazóis/síntese química , Ratos
12.
Guang Pu Xue Yu Guang Pu Fen Xi ; 32(12): 3381-4, 2012 Dec.
Artigo em Chinês | MEDLINE | ID: mdl-23427572

RESUMO

Using photodiode array (PDA) detector and spectrometer, a method on the basis of algorithm of nondispersive ultraviolet (NDUV) is described to measure and analyze nitric oxide (NO) gas. With the introduction of light source impact factor and absorption spectrum impact factor, fitting equation and correlation coefficient between absorbance and concentration was acquired through comparative analysis on the total intensity of nitric oxide absorption and non-absorption spectrum, which are collected in different integration times and within different wavelength width. The results show that second order fitting correlation coefficient related to absorbance and concentration is above 0.999 9 and the error of concentrations between the concentration calculated by fitting equation and the standard concentration is less than 3% through using suitable fitting order, fitting wavelength width and analysis method.

13.
Guang Pu Xue Yu Guang Pu Fen Xi ; 32(5): 1371-5, 2012 May.
Artigo em Chinês | MEDLINE | ID: mdl-22827092

RESUMO

A method of copper converting process determination based on PbO/PbS emission spectrum analysis was described. According to the known emission spectrum of gas molecules, the existence of PbO and PbS was confirmed in the measured spectrum. Through the field experiment it was determined that the main emission spectrum of the slag stage was from PbS, and the main emission spectrum of the copper stage was from PbO. The relative changes in PbO/PbS emission spectrum provide the method of copper converting process determination. Through using the relative intensity in PbO/PbS emission spectrum the copper smelting process can be divided into two different stages, i.e., the slag stage (S phase) and the copper stage (B phase). In a complete copper smelting cycle, a receiving telescope of appropriate view angle aiming at the converter flame, after noise filtering on the PbO/PbS emission spectrum, the process determination agrees with the actual production. Both the theory and experiment prove that the method of copper converting process determination based on emission spectrum analysis is feasible.

14.
Int J Pharm ; 613: 121403, 2022 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-34933079

RESUMO

Curcumin is used for the development of new pharmaceutical and food products, but its application is generally hindered by the poor solubility of curcumin and thermal instability during storage and processing. In this study, the liposomes of curcumin (cur-liposomes) were prepared by a novel combination of ethanol injection and high-pressure processing (HPP) to enhance the stability and preservation of curcumin. The pasteurization, mean particle size, size distribution, and encapsulation efficiency of cur-liposomes and the kinetics of their thermal degradation were also investigated in this research. From the results, the kinetic rate constants of curcumin in samples of free curcumin and cur-liposome at 25 °C were found to be 1.6 × 10-3 and 0.8 × 10-3 min-1, respectively. The phospholipid bilayer structure could protect curcumin. The results propose that the HPP method for liposome preparation is superior to the probe-sonication method in terms of stability, encapsulation efficiency, and homogeneity. Furthermore, the preparation of cur-liposomes by HPP with a hydrostatic pressure of 200 MPa could maintain the optimal particle size (206.4 nm) and polydispersity index (0.19). Conclusively, the combination of ethanol injection and HPP can not only successfully inactivate the microorganisms during liposome preparation for microencapsulation of bioactive compounds but also effectively preventthe thermal degradation of heat-sensitive substances in non-thermal processing for practical applications.


Assuntos
Curcumina , Portadores de Fármacos , Lipossomos , Tamanho da Partícula , Fosfolipídeos
15.
Sci Total Environ ; 804: 149680, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34509838

RESUMO

NO3 radicals can clean the atmospheric primary contaminants during the night. However, it can also effect the formation of secondary organic aerosol (SOA) and nitrate, which may worsen air quality. We report field observations of NO3 radicals with a home-made long path differential optical absorption spectroscopy (LP-DOAS) at a rural site in the polluted North China Plain in the summer of 2014. The detection limit (1σ) of NO3 with 3.4 km optical path was 3.4 ppt. The observed mean NO3 mixing ratios were 21 ppt with the maximum value of 104 ppt. The average calculated production rates and steady state lifetime of NO3 were 952 ppt/h and 103 s, respectively. The increase of both PM2.5 (>60 µg/m3) and RH (>60%) would result in an increase of the loss of NO3. The proportion of indirect losses rise with the increase of RH (>50%). The fitting kNO3 ranged from 0.0018 to 0.012 s-1 while γN2O5 was 0.0012 to 0.072. The ratios of direct loss ranged from 20.95% to 90.36% with an average of 56.81% during the campaign.


Assuntos
Poluentes Atmosféricos , Material Particulado , Poluentes Atmosféricos/análise , China , Monitoramento Ambiental , Material Particulado/análise , Análise Espectral
16.
Chem Phys Lipids ; 244: 105191, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35257749

RESUMO

Curcumin has been incorporated for the development of new products with applicability in food, pharmaceutical and cosmetic fields in Asia, due to the traits of anti-oxidation and anti-inflammatory. In the application of food engineering, high-pressure processing (HPP) can destroy non-covalent bonds and use as a method to inactivate bacteria for extending the perseveration of food. Thus, this study focuses on a novel approach for the microencapsulation of curcumin by the combination of ethanol injection and HPP at the room temperature for stabilizing pure curcumin in aqueous solutions and in liposome. The results revealed that the most optimal curcumin-liposome was prepared by HPP at operational pressure of 200 MPa within 5 mins holding time to obtain the minimum particle size of 281.9 nm, encapsulation efficiency of 87.25% and polydispersity index (PDI) of 0.23. Particle size could reduce to nanoscale (70.65 nm) after 0.5% addition of Tween 80, but the encapsulation efficiency spontaneously decreased to 45.05%. It is an option to produce liposome with nanosize and uniform distribution for the consideration of high drug delivery. Conclusively, HPP process could not only effectively decrease particle size and PDI of liposome but also efficiently sterilize bacteria around concentration of 103 CFU/g.


Assuntos
Curcumina , Lipossomos , Disponibilidade Biológica , Curcumina/química , Sistemas de Liberação de Medicamentos , Lipossomos/química , Tamanho da Partícula
17.
Cancer Manag Res ; 13: 941-951, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33568940

RESUMO

OBJECTIVE: This research was designed to probe into the expression and related mechanism of lncRNA NR2F1-AS1 and H19 in hepatocellular carcinoma (HCC). METHODS: Forty-two HCC patients who came to our hospital from February 2018 to August 2019 were included into a research group (RG). Meanwhile, 46 healthy controls were regarded as a control group (CG). BEL-7402, Huh-7 human hepatoma cells and HL-7702 human normal liver cells were purchased, and the NR2F1-AS1 and H19 levels in serum and tissues of HCC patients were detected. PcDNA3.1-NR2F1-AS1, si-NR2F1-AS1, NC, pcDNA3.1-H19 and si-H19 were transfected into BEL-7402 and Huh-7 cells. The NR2F1-AS1 and H19 levels in samples were detected via qRT-PCR, and the expression of apoptosis-related proteins in cells was tested through WB. Cell proliferation, invasion, or apoptosis was detected by CCK8, Transwell or flow cytometry, respectively. RESULTS: The NR2F1-AS1 and H19 levels were high in human hepatoma cells, and AUCs of lncRNA NR2F1-AS1 and lncRNA H19 were both >0.8. The lncRNA NR2F1-AS1 and lncRNA H19 were associated with HCC staging. After transfection of pcDNA3.1-NR2F1-AS1, si-NR2F1-AS1, NC, pcDNA3.1-H19, si-H19 BEL-7402 and Huh-7 cells, silencing NR2F1-AS1 and H19 expression can promote apoptosis and inhibit cell growth, while silencing their over-expression can inhibit the EMT process of Huh-7 cells. CONCLUSION: lncRNA NR2F1-AS1 and lncRNA H19 genes are abnormally expressed in HCC. Furthermore, the two can suppress the EMT process of Huh-7 cells and promote apoptosis effectively.

18.
PeerJ ; 9: e12437, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34909269

RESUMO

BACKGROUND: Agro-industrial waste from tropical environments could be an important source of lactic acid bacteria (LAB) with probiotic potential. METHODS: Twelve LAB isolates were isolated from pineapple silages. The species identification was carried out considering 16S rRNA and pheS genes. Experiments to evaluate the probiotic potential of the isolates included survival under simulated gastrointestinal environment, in vitro antagonistic activity (against Salmonella spp. and Listeria monocytogenes), auto-aggregation assays, antibiotic susceptibility, presence of plasmids, adhesiveness to epithelial cells, and antagonistic activity against Salmonella in HeLa cells. RESULTS: Lacticaseibacillus paracasei, Lentilactobacillus parafarraginis, Limosilactobacillus fermentum, and Weissella ghanensis were identified. Survival of one of the isolates was 90% or higher after exposure to acidic conditions (pH: 2), six isolates showed at least 61% survival after exposure to bile salts. The three most promising isolates, based on survivability tests, showed a strong antagonistic effect against Salmonella. However, only L. paracasei_6714 showed a strong Listeria inhibition pattern; this isolate showed a good auto-aggregation ability, was resistant to some of the tested antibiotics but was not found to harbor plasmids; it also showed a high capacity for adhesion to epithelial cells and prevented the invasion of Salmonella in HeLa cells. After further in vivo evaluations, L. paracasei_6714 may be considered a probiotic candidate for food industry applications and may have promising performance in acidic products due to its origin.

19.
Pharmaceutics ; 13(1)2020 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-33374428

RESUMO

Toxic organic solvent residues and the active substances of thermal degradation (such as anthocyanin and polyphenols) are always a concern with the liposomes produced by traditional techniques. The present study focuses on a new approach for the microencapsulation of Clitoria ternatea petal (CTP) extracts, which contain anthocyanins, by high-pressure processing (HPP) at room temperature. Thus, a series of CTP liposomes were prepared and their physicochemical properties were analyzed by laser granulometry and by scanning electron microscopy (SEM). The results revealed that the average particle size of the liposomes after HPP treatment increased gradually from 300 MPa to 600 MPa, possibly due to the aggregation of liposomes and damage to the phospholipid bilayers. For the preparation of liposomes by the HPP method at 300 MPa, the mean particle size, polydispersity index (PDI), and encapsulation efficiency were 240.7 nm, 0.37, and 77.8%, respectively. The HPP method provided a number of advantages over conventional methods (magnet stirring and ultrasonication) as it could allow liposome preparation with higher encapsulation efficiency, smaller size, and narrower, more reproducible particle size distribution. Conclusively, microencapsulation in the liposomes was successfully achieved with the fast-adiabatic expansion of HPP.

20.
Sci Total Environ ; 745: 140867, 2020 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-32738680

RESUMO

An automated dynamic chamber system was first developed to simultaneously measure the HONO flux and NOx flux. The new dynamic chamber system was applied to field observation, and the HONO and NOX exchange flux of farmland in the Huaihe River Basin was obtained for the first time. The performance of the dynamic chamber system was verified in the field. In the field observation, the diurnal variations of the HONO fluxes and NO fluxes before and after a rainfall event exhibited two different trends. Before the rainfall and in the latter stage after the rainfall, the maxima of the HONO fluxes and NO fluxes occurred in the morning, then decreased gradually. However, during the early stage after the rainfall, the HONO fluxes and NO fluxes gradually increased in the morning and reached their maximum values in the afternoon. During the measurement period, the maximum HONO flux was 7.69 ng N m-2 s-1 and the maximum NO flux was 34.52 ng N m-2 s-1. There was no significant correlation between HONO flux and temperature before the rainfall and in the latter stage after the rainfall period, although the correlation coefficient (R) between HONO flux and temperature reached 0.78 in the early stage after the rainfall period, and the R between NO flux and HONO flux reached more than 0.6 before and after rainfall periods. The HONO flux of fresh soil samples were the same order of magnitude as that of field observations. The field results indicate that soil emissions are an important source of atmospheric HONO during the crop growth stage. Negative NO2 fluxes were found in most observation periods, and there were significant negative linear correlations between NO2 fluxes and atmospheric NO2 concentrations. The R between ambient NO2 concentration and NO2 flux was 0.79, and the compensation point of NO2 was 5 ppbv.

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