Search

ObjectiveThis study aims to conducting a survey on the consumption of nine pilot edible and medicinal substances including Codonopsis pilosula and etc.， and provides a basis for supplementing the database of food safety assessment.MethodsNineteen cities in Guangdong Province were selected as sample sites from 2019 to 2021. Healthy individuals aged 18 years and above who had the habit of eating traditional local food such as soup ingredients were selected as candidate subjects. A food frequency questionnaire was applied for collecting information on the consumption of the nine pilot edible and medicinal substances over the past 12 months.ResultsThis study enrolled a total of 6 233 participants， with 49.2% male and 50.8% female. Among the study population， the consumption rates of the nine pilot edible and and medicinal substances ranged from 0.8% to 55.3%， The consumption rates from high to low are as follows： Codonopsis pilosula（Franch.）Nannf.（55.3%）， Astragalus membranaceus （Fisch.） Bge.var.mongholicus （Bge.） Hsiao （47.4%）， Panax quinquefolium L. （41.5%）， Ganoderma lucidum （Leyss. Ex Fr.）Karst. （dry） （30%）， Dendrobium officinale Kimura et Migo （24.1%）， Gastrodia elata B1. （16%）， Dendrobium officinale Kimura et Migo （wet） （4.8%）， Cistanche deserticola Y.C.Ma （2.6%）， Eucommia ulmoides Oliv. （1.3%）， Cornus officinalis Sieb.et Zucc. （0.8%）. Among the consumer population， the primary mode of consumption for the nine pilot edible and medicinal substances is indirect， accounting for 82.6% to 95.1%. The average monthly consumption frequency ranges from 0.8 to 2.2 times per month. The mean consumption quantity per occasion for the selected dried food-medicinal substances ranges from 7.4 to 11.9 grams， However， the mean consumption quantity per occasion for Dendrobium officinale Kimura et Migo （wet） is 41.9 grams.ConclusionThere are significant differences in the consumption rates of the nine pilot edible and medicinal substances among adults in the 19 municipalities of Guangdong province. The consumption quantity per occasion is high in some substances such as Codonopsis pilosula（Franch.）Nannf.， Astragalus membranaceus （Fisch.） Bge.var.mongholicus （Bge.） Hsiao. It is recommended to further scientifically evaluate the usage and dosage of these food-medicinal substances and make public education on the correct consumption of food for residents.

This paper firstly proposes distributed fiber optic sensing technology based on big data technology and physics, distributed fiber optic sensing technology includes distributed fiber optic sensing technology based on interference type and distributed fiber optic sensing technology based on the scattering principle. Then investigated the demand for remote monitoring of distributed fiber optic sensing systems and the demand for large sensing networks in the Internet of Things and designed a long-distance distributed fiber optic sensing-based intelligent monitoring system. Finally, the vibration acceleration signal of the metal shell when partial discharge occurs is collected, and the high-frequency components in the vibration acceleration signal are used to diagnose and analyze the discharging faults caused by the metal particles of GIL. The results show that: when the rated current is loaded on the GIL, the main frequency distribution of the vibration acceleration signal on the surface of the metal shell is from 0 to 1 kHz, and the percentage of the signal energy in this frequency band is greater than 99% of the total energy in the range of 0 to 20 kHz. In the frequency range of 1 kHz to 20 kHz, the percentage of the signal energy in the total energy does not exceed 1%, and there is almost no high-frequency vibration acceleration signal. This study and the combination of these two technologies is a great contribution to the further development of each, but also more favorable for application in work and life.

ObjectiveTo provide data basis for improving the accuracy of food safety risk assessment in China， the cooking coefficients of five toxic metals in marine fish was studied.MethodsBased on the consumption of 19 kinds of marine fish in Guangdong province， samples were divided into steamed， fried， roasted group and a control group （raw fish）. The concentrations of the total mercury， methyl mercury， arsenic， cadmium and lead were determined before and after the cooking process， and the cooking coefficients of five toxic metals were calculated.ResultsThe concentrations of total mercury， methyl mercury， total arsenic and cadmium in fried and roasted fish were significantly higher than those in control group （P

In view of the low calculation accuracy of physical analytical model of harmonic loss,a support vector regression (SVR) model based on crisscross optimization (CSO) algorithm is proposed to evaluate the harmonic loss of overhead lines. Firstly,the SVR model designed to minimize structural risk is used to fit the relationship between line characteristics and harmonic losses. Then,the SVR hyperparameters are globally searched by the CSO algorithm. The optimal hyperparameter group is obtained by dynamic optimization,and the CSO-SVR harmonic loss evaluation model is established. Based on a large power quality test platform,the harmonic test of low voltage overhead lines is carried out. And the proposed model is verified by the measured data of this test. The results show that using CSO algorithm to optimize hyperparameters of SVR can effectively improve the line loss evaluation performance of SVR model. Compared with other models,the proposed model presents higher accuracy.

ObjectiveTo evaluate the chronic and acute exposure risk of the 13 commonly used pesticides in local tea samples in Guangdong Province， so as to provide the basis and technical support for production supervision and consumption， and provide data for the revision of maximum residue limits （MRLs）.Methods110 local tea samples were collected from the year 2017—2020， and 13 pesticide residues were detected and quantified following the GB 23200.113-2018 method based on GC-MS/MS. Acute and chronic cumulative risk assessment were calculated using hazard index （HI） approach.Results8 kinds of pesticides in 110 local tea samples were detected in which the detection rates and the residue levels of bifenthrin， fenpropathrin and cypermethrin were the highest. The cumulative chronic and acute exposure levels of bifenthrin， fenpropathrin and cypermethrin to tea intake of Guangdong residents were 4.87×10-5 mg/（kg bw·d） and 4.79×10-3 mg/（kg bw·d）， accounting for 89.09% and 86.01% of the total pesticide exposure， respectively. The chronic and acute exposure level of males were higher than females， and urban residents were higher than rural residents. For all the pesticides detected， their chronic and acute cumulative hazard indexes were 3.69×10-3 and 4.66×10-1， respectively， which indicated that the risk was low.ConclusionThe chronic and acute dietary exposure risk of pesticide residues from local tea were both low， but pesticide residues in Guangdong province were common， so the application and management of pesicides in local tea should be further strengthened.

ObjectiveTo analyze the epidemiological characteristics of Bongkrekic Acid poisoning due to contamination of nonfermented rice noodle products in Guangdong Province, and provide the scientific basis for the prevention and control of Bongkrekic Acid poisoning.MethodsEpidemiological characteristics of Bongkrekic Acid poisoning in Guangdong Province were analyzed using descriptive epidemiological method.ResultA total of 5 Bongkrekic Acid poisoning events due to contamination of nonfermented rice noodle products were reported in Guangdong Province, including 21 cases and 9 deaths. The case fatality was 42.9%. The major clinical manifestation included vomiting, diarrhea and abdominal pain. The Bongkrekic Acid poisoning events mainly occurred during the third and fourth quarters. The food products involved in the 5 events were wet starch products or wet rice products mass-produced by food processing plants. Different from traditional nonfermented rice noodle products in Guangdong Province, these involved food products were added with a large amount of starch, using sodium dehydroacetate, and stored at room temperature for more than 24 hours, but there was no noticeable spoilage.ConclusionThe 5 nonfermented rice noodle products poisoning events were rare Bongkrekic Acid poisoning events caused by processed foods. It is urgent to further analyze the corresponding potential risks in the production and operation of nonfermented rice noodle products, as well as propose the targeted control measures. At the same time, the food safety education should be strengthened. Wet rice noodles and wet starch products should be stored in cold storage and should be sold or consumed within the shelf life.

ObjectiveTo analyze the intake and source of fat and fatty acids of urban residents in Guangdong Province.MethodsResidents aged 3 years and above were selected by multi-stage stratified cluster sampling method in 5 cities in Guangdong Province from 2017 to 2018, and non-continuous 3 d-24 h retrospective survey was conducted to collect the dietary intake information of the respondents.ResultsThe average daily energy intake and fat intake of urban residents in Guangdong Province were 1671.9 kcal and 69.2 g, and the energy proportion contributed from fat was 39.4%. The energy proportion contributed from fat of urban residents in big cities was higher than that in small and medium-sized cities (39.9% vs 39.0%, P < 0.05). 1.6% of the residents’ energy proportion contributed from fat was lower than 20%, 14.8% of the residents' proportion met the standard, and 83.6% of the residents’ proportion was 20%-30%. Fat intake mainly came from animal food (52.8%) and vegetable oil (30.9%). The proportion of total fat from vegetable oil in small and medium-sized cities was higher than that in large cities (32.7% vs 27.7%, P

Indium oxide semiconductors, as one of the channel materials for thin film transistors (TFTs), have been extensively studied. However, the high carrier concentration and excess oxygen defects of intrinsic In2O3 can cause the devices to fail to work properly. We overcame this hurdle by incorporating the titanium cation (Ti4+) into In2O3 via atomic layer deposition (ALD). The InTiOx TFTs with an In:Ti atomic ratio of 15:1 demonstrated excellent electrical and optical properties, such as a lower threshold voltage (Vth) of 0.17 V, a lower subthreshold swing (SS) of 0.13 V/dec., a higher Ion/Ioff ratio of 107, and a transmittance greater than 90% in the visible region. With the doping ratio increasing from 20:1 to 10:1, the mobility decreased from 9.38 to 1.26 cm2/Vs. The threshold voltage shift (ΔVth) of InTiO (15:1) under 5 V positive bias stress (PBS) for 900 s is 0.93 V, which is less than other devices. The improvement in stability with increasing Ti4+ concentrations is attributed to the reduction of oxygen defects. Therefore, these InTiO (15:1) TFTs with excellent performance show great potential for future applications in transparent electronic devices. [ABSTRACT FROM AUTHOR]

Aggregation is a key process for determining the environmental behavior and impact of a nanoparticle (NP). Since organophosphate esters (OPEs), which are recognized as emerging contaminants, are distributed widely in the natural aquatic environment, they may contribute to interacting with NPs and ultimately influence their transport and fate. Here, we investigated two typical organophosphate esters OPEs on aggregation the Fe 2 O 3 NP in aquatic environments. The results showed that both tri-ethylhexyl phosphate (TEHP) and tris (chloroisopropyl) phosphate (TCPP) improved the colloidal stability of Fe 2 O 3 NP in artificial water and environmental matrices. TEHP exhibited an obvious effect than TCPP on the Zeta potential and aggregation rates of Fe 2 O 3 NP in artificial water. In the presence of electrolyte, 10 mg/L TCPP and TEHP increased the critical coagulation concentration (CCC) by 3.6 times and 17.4 times, respectively. Compared with pore-water, the aggregation rates of Fe 2 O 3 NP in river water were slightly higher than those in pore-water, which can be attributed to the higher DOC in pore-water. We suggested that the high hydrophobicity and molecular weight of OPEs were considered important factors against the aggregation of Fe 2 O 3 NP in water. Greater surface charge and steric hindrance originating from TCPP and TEHP dominated the colloidal stability of Fe 2 O 3 NP.

The photoresponsive J-aggregation behaviors of a novel azobenzene-substituted zinc phthalocyanine (azo-ZnPc dyad) were studied by UV/vis, fluorescence, and (1)H NMR spectroscopy. Upon illumination with 365 nm UV light, the trans-cis isomerization of azobenzene can efficiently reduce the steric hindrance around the peripheral oxygen atom of azo-ZnPc, shortening the possible distance between two phthalocyanine molecules and, consequently, greatly improving the tendency of J-aggregation of azo-ZnPc dyad. The third-order optical nonlinearities of the photoresponsive J-aggregates (before and after illumination) were measured by a Z-scan technique at 532 nm with a pulse duration of 25 ps. The Z-scan spectra revealed that all the samples possessed large positive nonlinear refraction and positive nonlinear absorption, exhibiting a self-focusing effect and reverse saturable absorption, respectively. The second molecular hyperpolarizabilities of the dyad in two conditions were measured to be 3.87 x 10(-30) and 4.82 x 10(-30) esu, respectively. All the results suggest that the azo-ZnPc dyad has potential in the field of nonlinear optics applications.