Association Between Home Renovation and Sleeping Problems Among Children Aged 6-18 Years: A Nationwide Survey in China.

BACKGROUND: Although the indoor environment has been proposed to be associated with childhood sleep health, to our knowledge no study has investigated the association between home renovation and childhood sleep problems. METHODS: The study included 186,470 children aged 6-18 years from the National Chinese Children Health Study (2012-2018). We measured childhood sleeping problems via the Chinese version of the Sleep Disturbance Scale for Children (C-SDSC). Information on home renovation exposure within the recent 2 years was collected via parent report. We estimated associations between home renovation and various sleeping problems, defined using both continuous and categorized (binary) C-SDSC t-scores, using generalized mixed models. We fitted models with city as a random effect variable, and other covariates as fixed effects. RESULTS: Out of the overall participants, 89,732 (48%) were exposed to recent home renovations. Compared to the unexposed group, children exposed to home renovations had higher odds of total sleep disorder (odd ratios [OR] = 1.3; 95% confidence interval [CI] = 1.2, 1.4). Associations varied when we considered different types of home renovation materials. Children exposed to multiple types of home renovation had higher odds of sleeping problems. We observed similar findings when considering continuous C-SDSC t-scores. Additionally, sex and age of children modified the associations of home renovation exposure with some of the sleeping problem subtypes. CONCLUSIONS: We found that home renovation was associated with higher odds of having sleeping problems and that they varied when considering the type of renovation, cumulative exposure, sex, and age differences.

In situ Raman reveals the critical role of Pd in electrocatalytic CO2 reduction to CH4 on Cu-based catalysts.

Electrocatalytic CO2 reduction reaction (CO2RR) for CH4 production presents a promising strategy to address carbon neutrality, and the incorporation of a second metal has been proven effective in enhancing catalyst performance. Nevertheless, there remains limited comprehension regarding the fundamental factors responsible for the improved performance. Herein, the critical role of Pd in electrocatalytic CO2 reduction to CH4 on Cu-based catalysts has been revealed at a molecular level using in situ surface-enhanced Raman spectroscopy (SERS). A "borrowing" SERS strategy has been developed by depositing Cu-Pd overlayers on plasmonic Au nanoparticles to achieve the in situ monitoring of the dynamic change of the intermediate during CO2RR. Electrochemical tests demonstrate that Pd incorporation significantly enhances selectivity toward CH4 production, and the Faradaic efficiency (FE) of CH4 is more than two times higher than that for the catalysts without Pd. The key intermediates, including *CO2-, *CO, and *OH, have been directly identified under CO2RR conditions, and their evolution with the electrochemical environments has been determined. It is found that Pd incorporation promotes the activation of both CO2 and H2O molecules and accelerates the formation of abundant active *CO and hydrogen species, thus enhancing the CH4 selectivity. This work offers fundamental insights into the understanding of the molecular mechanism of CO2RR and opens up possibilities for designing more efficient electrocatalysts.

Rapid screening and evaluation of natural antioxidants from leaf, stem, and root of Artemisia argyi by online liquid microextraction combined with HPLC-based antioxidant assay system coupled with calibration quantitative analysis.

To reveal the utilization value of leaf, stem, and root of Artemisia argyi, a rapid online liquid microextraction combined with a high-performance liquid chromatography coupled with 2,2-nitrogen-di (3-ethyl-benzothiazole-6-sulfonic acid) diammonium salt antioxidant assay system was established for analysis of antioxidants in the leaf, stem, and root of A. argyi, and a calibration quantitative method of antioxidant activity with equivalent chlorogenic acid was proposed. Thirty-three positive peaks were identified; among them, 12 compounds were found that possess good antioxidant activity including eleven organic acids (components 2-4, 8, 11-14, 17, 19, and 21) and one flavonoids (component 22). The proposed calibration quantitative method avoided the influence of content of compound and compared the extent of radical scavenging capacity of five antioxidant compounds, which were ranked as follow: 3,5-dicaffeoylquinic acid > 3,4-dicaffeoylquinic acid ≈ 4,5-dicaffeoylquinic acid > 1,4-dicaffeoylquinic acid > chlorogenic acid. In conclusion, this study provided composition and biological potential for the future development of the leaf, stem, and root of A. argyi. It is believed that the online liquid microextraction combined with high-performance liquid chromatography based antioxidant assay system can be widely used for the rapid screening of natural antioxidant components in the different parts of natural products.

Detection of Arsenic(V) by Fluorescence Sensing Based on Chlorin e6-Copper Ion.

The high toxicity of arsenic (As) can cause irreversible harm to the environment and human health. In this study, the chlorin e6 (Ce6), which emits fluorescence in the infrared region, was introduced as the luminescence center, and the addition of copper ion (Cu2+) and As(V) provoked a regular change in fluorescence at 652 nm, whereas that of As(III) was 665 nm, which was used to optionally detect Cu2+, arsenic (As(III), and As(V)). The limit of detection (LOD) values were 0.212 µM, 0.089 ppm, and 1.375 ppb for Cu2+, As(III), and As(V), respectively. The developed method can be used to determine Cu2+ and arsenic in water and soil with good sensitivity and selectivity. The 1:1 stoichiometry of Ce6 with Cu2+ was obtained from the Job plot that was developed from UV-visible spectra. The binding constants for Cu2+ and As(V) were established to be 1.248 × 105 M-1 and 2.35 × 1012 M-2, respectively, using B-H (Benesi-Hildebrand) plots. Fluorescence lifetimes, B-H plots, FT-IR, and 1H-NMR were used to postulate the mechanism of Cu2+ fluorescence quenching and As(V) fluorescence restoration and the interactions of the two ions with the Ce6 molecule.

Application of definitive screening design to optimization of the protein extraction and functional properties of proteins in Auricularia auricula.

BACKGROUND: Auricularia auricula (A. auricula) is one of the most abundant sources of plant protein in edible fungi. Problems of low protein yield exist in traditional methods of protein extraction such as alkali extraction and ultrasonic-assisted alkali after pretreatment with enzymes. Thus, the protein extraction process was investigated and optimized using a definitive screening design from A. auricula to improve the protein yield under practical operating conditions of temperature, the concentration of NaCl, meal/water ratio, extraction time and pH. RESULTS: The yield of protein isolates of the isoelectric-ammonium sulfate precipitation (9.34% w/w) was obtained almost three times and the protein content (55.23% w/w) was approximately 1.6 times that of the traditional extraction method of isoelectric precipitation. Next, the optimized method was successfully applied to the analysis of the functional properties of the protein. A. auricula protein isolate (AAPI) had better solubility, emulsification and foaming capacity than soy protein isolate (SPI) and pea protein isolate (PPI), and the oil holding capacity of AAPI exhibited extremely well, which was approximately five times that of SPI and six times that of PPI. The texture properties of AAPI gel were similar to those of PPI gels. CONCLUSION: AAPI extracted by the optimized method had a satisfactory yield and had the potential to substitute plant-originated proteins in food processing. © 2022 Society of Chemical Industry.

A Sensitive and Selective Colorimetric Method Based on the Acetylcholinesterase-like Activity of Zeolitic Imidazolate Framework-8 and Its Applications.

In this study, a simple colorimetric method was established to detect copper ion (Cu2+), sulfathiazole (ST), and glucose based on the acetylcholinesterase (AChE)-like activity of zeolitic imidazolate framework-8 (ZIF-8). The AChE-like activity of ZIF-8 can hydrolyze acetylthiocholine chloride (ATCh) to thiocholine (TCh), which will further react with 5,5'-dithiobis (2-nitrobenzoic acid) (DTNB) to generate 2-nitro-5-thiobenzoic acid (TNB) that has a maximum absorption peak at 405 nm. The effects of different reaction conditions (buffer pH, the volume of ZIF-8, reaction temperature and time, and ATCh concentration) were investigated. Under the optimized conditions, the value of the Michaelis-Menten constant (Km) is measured to be 0.83 mM, which shows a high affinity toward the substrate (ATCh). Meanwhile, the ZIF-8 has good storage stability, which can maintain more than 80.0% of its initial activity after 30 days of storage at room temperature, and the relative standard deviation (RSD) of batch-to-batch (n = 3) is 5.1%. The linear dependences are obtained based on the AChE-like activity of ZIF-8 for the detection of Cu2+, ST, and glucose in the ranges of 0.021-1.34 and 5.38-689.66 µM, 43.10-517.24 µM, and 0.0054-1.40 mM, respectively. The limit of detections (LODs) are calculated to be 20.00 nM, 9.25 µM, and 5.24 µM, respectively. Moreover, the sample spiked recoveries of Cu2+ in lake water, ST in milk, and glucose in strawberry samples were measured, and the results are in the range of 98.4-115.4% with the RSD (n = 3) lower than 3.3%. In addition, the method shows high selectivity in the real sample analysis.

[Form and valence of arsenic in dry and fresh Cordyceps breeding products based on HPLC-ICP-MS and its risk assessment].

A comparative study was conducted for the first time on the form and valence of arsenic in the dry and fresh Cordyceps breeding products to clarify the specific morphology and valence of arsenic in Cordyceps breeding products and its safety. Arsenic betai-ne(AsB), arsenite(AsⅢ), dimethyl arsenic(DMA), arsenocholine(AsC), monomethyl arsenic(MMA), and arsenate(AsⅤ) in the dry and fresh samples were investigated using a bionic extraction method combined with HPLC-ICP-MS. The HPLC separation was performed on a DioncxIonPac~(TM) AS7 anion exchange column with a mobile phase of 100 mmol·L~(-1) ammonium carbonate-water for gradient elution at room temperature and the flow rate of 0.8 mL·min~(-1). HPLC was coupled with ICP-MS for the determination. The arsenic content was characterized in combination with chemometrics. The health safety risk of inorganic arsenic in the samples was assessed using the margin of exposure(MOE). The results of methodological validation showed that the six arsenic compounds showed good linearity(R~2>0.999) from 10 to 500 ng·mL~(-1), with precision RSDs of 1.8%-3.0%, recoveries(n=6) of 84.15%-98.28%, reproducibility RSDs of 6.4%-7.7%, and sample stability RSDs of 8.3%-14% within 10 h. Trace AsⅢ and AsⅤ were detected in 30 batches of dry and fresh Cordyceps breeding products, while arsenic compounds in other forms and valence were not detected. In the dry products, AsⅢ was 0.019-0.040 mg·kg~(-1) and AsV was 0.024-0.061 mg·kg~(-1), while in the fresh products, AsⅢ was 0.002 3-0.006 1 mg·kg~(-1) and AsⅤ was 0.008-0.016 mg·kg~(-1). The risk assessment results showed that the MOE of inorganic arsenic was much higher than 1 in both dry and fresh products, and the potential health safety risk of inorganic arsenic was low. The HPLC-ICP-MS method established in this study was efficient, rapid, accurate, and stable for the determination of six arsenic compounds in Cordyceps breeding products. The results of this study provide a basis for the safety and quality control of Cordyceps breeding products.

Enhanced Adsorption and Separation of Xenon over Krypton via an Unsaturated Calcium Center in a Metal-Organic Framework.

Krypton (Kr) and xenon (Xe) are nowadays widely applied in technical and industrial fields. Separating and collecting highly pure Xe from nuclear facilities are necessary and urgent. However, the technology is limited due to the inert nature of Xe and other interferential factors. In this work, a calcium-based metal-organic framework, Ca-SINAP-1, which comprises a three-dimensional microporous framework with a suitable pore width, was researched for xenon and krypton separation through both experimental and theoretical methods. Ca-SINAP-1, synthesized in solvothermal and gamma ray conditions, features accessible open-metal sites, exhibits a high Xe/Kr selectivity of 10.32, and owns a Xe adsorption capacity of 2.87 mmol/g at room temperature (1.0 bar). Particularly, its excellent chemical stability (from pH 2 to 13) and thermal stability (up to 550 °C), as well as radiation-resistance (up to 400 kGy ß irradiations), render this material a promising candidate for radioactive inert gases treatment.

A portable personal glucose meter method for enzyme activity detection and inhibitory activity evaluation based on alkaline phosphatase-mediated reaction.

In this study, an effective and portable method for enzyme activity detection and inhibitory activity evaluation was developed based on the alkaline phosphatase (ALP)-mediated reaction in a personal glucose meter (PGM). In this method, ALP catalyzes the hydrolysis of substrate amifostine (WR-2721) to produce ethanethiol (WR-1065), which can trigger the reduction of ferricyanide (K3[Fe(CN)6]), an electron transfer mediator in glucose test strips, to ferrocyanide ([K4Fe(CN)6]) and generate a PGM-detectable signal. Thus, WR-1065 can be directly quantified by a PGM as simply as detecting glucose in blood. After being systematically optimized, the method was applied to evaluate the inhibitory activity of ten small-molecule compounds and six Cordyceps sinensis (CS) extracts on ALP. The results showed that adenosine-5-monophosphate and theophylline had high inhibitory activity, but two CS extracts have promotion potency on ALP with the values of -20.7 ± 1.3% and -46.6 ± 2.1%, respectively. Moreover, the binding sites and modes of small-molecule compounds to ALP were investigated by molecular docking, while a new substrate competitor with theoretically good inhibitory activity against ALP was designed by scaffold hopping. Finally, the accuracy of the PGM method for enzyme activity detection was assessed by detecting ALP from milk samples, and the recovery ranged from 87.7% to 116.9%. These results indicate that it is feasible to evaluate enzyme activity and the inhibitory activity of small-molecule compounds and CS extracts on ALP using a PGM based on ALP-mediated reaction. Graphical abstract.

Ocean mixed layer depth estimation using airborne Brillouin scattering lidar: simulation and model.

The potential of Brillouin scattering lidar for detecting the mixed layer depth (MLD) was studied. We simulated the Brillouin scattering lidar signal in various water environmental parameters and developed an MLD retrieval model for Brillouin scattering lidar data. We first analyzed the theoretical maximum detectable depth for Brillouin scattering lidar in low-latitude sea regions based on the multiple scattering lidar equations. Subsequently, a theoretical method for calculating the Brillouin scattering frequency shift and linewidth was derived based on the international thermodynamic equation of seawater-2010 and the coupled wave equations. Then we used the theoretical method and the temperature-salinity (T-S) profile of the global Argo data in low-latitude regions to simulate the vertical profile distribution of the Brillouin scattering frequency shift and linewidth. Furthermore, we used a maximum angle method to estimate the ocean MLD in low-latitude regions based on the vertical profile distribution of the Brillouin scattering frequency shift and density in seawater. They are well correlated, which indicates that the frequency-shift component of the Brillouin scattering lidar signal for estimating ocean MLD is feasible and reliable. It appears that airborne or spaceborne Brillouin scattering lidar technology provides great potential for high-efficiency, large-area, and long-term monitoring of the global ocean MLD and upper-ocean water bodies.

Cyclin-dependent kinase like 3 promotes triple-negative breast cancer progression via inhibiting the p53 signaling pathway.

It has been reported that cyclin-dependent kinase like 3 (CDKL3) plays a crucial role in cell proliferation and migration in several cancers. However, the function of CDKL3 in triple-negative breast cancer (TNBC) is still unclear. In the present study, immunohistochemistry (IHC) was conducted to detect the CDKL3 expression. CCK-8, flow cytometry, Transwell assays, and mice xenograft models, were performed to explore the roles of CDKL3 on the proliferation and migration of TNBC in vitro and in vivo. Besides, protein chip analysis was used to screen the potential pathways, which was further confirmed by promoter activity assay, western blotting, and CCK-8 assay. Our findings reveal a high expression of CDKL3 in TNBC tissues, which is closely related to a poor prognosis of patients with TNBC. In TNBC cells, CDKL3 knockdown inhibits cell proliferation and migration, whereas CDKL3 overexpression has exactly the opposite effect. Consistently, CDKL3 knockdown induces cell apoptosis in vitro but suppresses tumor growth in vivo. Furthermore, CDKL3 knockdown increases p53 expression and reduces cell viability, and these effects are significantly weakened by the p53 inhibitor, PFT-α. In conclusion, the current study highlights that CDKL3 promotes TNBC progressions via regulating the p53 signaling pathway, suggesting that CDKL3 is a novel therapeutic target for TNBC treatment.

Research of Probability-Based Tunneling Magnetoresistive Sensor Static Hysteresis Model.

Tunneling magnetoresistive (TMR) sensors have broad application prospects because of their high sensitivity and small volume. However, the inherent hysteresis characteristics of TMR affect its applications in high accuracy scenarios. It is essential to build a model to describe the attributes of hysteresis of TMR accurately. Preisach model is one of the popular models to describe the behavior of inherent hysteresis for TMR, whereas it presents low accuracy in high-order hysteresis reversal curves. Furthermore, the traditional Preisach model has strict congruence constraints, and the amount of data seriously affects the accuracy. This paper proposes a hysteresis model from a probability perspective. This model has the same computational complexity as the classic Preisach model while presenting higher accuracy, especially in high-order hysteresis reversal curves. When measuring a small amount of data, the error of this method is significantly reduced compared with the classical Preisach model. Besides, the proposed model's congruence in this paper only needs equal vertical chords.

The Experimental Registration of the Evanescent Acoustic Wave in YX LiNbO3 Plate.

Evanescent acoustic waves are characterized by purely imaginary or complex wavenumbers. Earlier, in 2019 by using a three dimensional (3D) finite element method (FEM) the possibility of the excitation and registration of such waves in the piezoelectric plates was theoretically shown. In this paper the set of the acoustically isolated interdigital transducers (IDTs) with the different spatial periods for excitation and registration of the evanescent acoustic wave in Y-cut X-propagation direction of lithium niobate (LiNbO3) plate was specifically calculated and produced. As a result, the possibility to excite and register the evanescent acoustic wave in the piezoelectric plates was experimentally proved for the first time. The evanescent nature of the registered wave has been established. The theoretical results turned out to be in a good agreement with the experimental ones. The influence of an infinitely thin layer with arbitrary conductivity placed on a plate surface was also investigated. It has been shown that the frequency region of an evanescent acoustic wave existence is very sensitive to the changes of the electrical boundary conditions. The results obtained may be used for the development of the method of the analysis of thin films electric properties based on the study of evanescent waves.

Investigation on the adsorption of antibiotics from water by metal loaded sewage sludge biochar.

Application of sewage sludge biochar as an adsorbent for antibiotics treatment has obtained special attention owning to its low cost and surface functionality. Three metal ions were selected to modify sewage sludge biochar through the pyrolysis with the metal loaded method. Fe loaded sewage sludge biochar (BC-Fe), Al loaded sewage sludge biochar (BC-Al) and Mn loaded sewage sludge biochar (BC-Mn) were characterized and used to explore the performance of adsorbing tetracycline (TC), sulfamethoxazole (SMZ) and amoxicillin (AMC). BC-Fe, BC-Al and BC-Mn possessed rougher surfaces, larger specific surface area and better pore structure. Intra-particle diffusion and Langmuir models were more suitable to describe the adsorption process. The maximum adsorption amount of TC, SMZ and AMC could reach 123.35, 99.01 and 109.89 mg/g by BC-Fe. Furthermore, the main mechanism of antibiotics adsorption by metal loaded sewage sludge biochars might be pores filling, Van der Waals forces and H-bonding. The study can not only solve the problems associated with the pollution of antibiotics from wastewater, but also reduced the treatment pressure of sewage sludge effectively.

Human African trypanosomiasis: the current situation in endemic regions and the risks for non-endemic regions from imported cases.

Human African trypanosomiasis (HAT) is caused by Trypanosoma brucei gambiense and Trypanosoma brucei rhodesiense and caused devastating epidemics during the 20th century. Due to effective control programs implemented in the last two decades, the number of reported cases has fallen to a historically low level. Although fewer than 977 cases were reported in 2018 in endemic countries, HAT is still a public health problem in endemic regions until it is completely eliminated. In addition, almost 150 confirmed HAT cases were reported in non-endemic countries in the last three decades. The majority of non-endemic HAT cases were reported in Europe, USA and South Africa, due to historical alliances, economic links or geographic proximity to disease-endemic countries. Furthermore, with the implementation of the 'Belt and Road' project, sporadic imported HAT cases have been reported in China as a warning sign of tropical diseases prevention. In this paper, we explore and interpret the data on HAT incidence and find no positive correlation between the number of HAT cases from endemic and non-endemic countries. This data will provide useful information for better understanding the imported cases of HAT globally in the post-elimination phase.

[Composition analysis and antioxidant activity of polysaccharide from Hibiscus syriacus].

The flower of Hibiscus syriacus has good ornamental and edible-medicinal values.In this study,four samples of two varieties,namely white multiple petals flower and pink multiple petals flower,were selected as test materials.And the optimum extraction conditions,relative molecular weight,monosaccharide composition and antioxidant activity of polysaccharides in flower were investigated.Through single factor experiment and response surface,the optimal extract conditions of polysaccharide were designed as follows:extraction temperature at 96.8℃,ratio of material to liquid of 43.5∶1 m L·g~(-1),extraction time of 3.1 h.Polysaccharides of H.syriacus flowers were analyzed by high performance gel chromatography.The average molecular masses of the 4 polysaccharide samples were1.49×10~5,1.25×10~5,1.01×10~5,1.37×10~5,respectively.Polysaccharides of H.syriacus flowers were mainly composed of glucose,mannose,galactose,rhamnose and arabinose by pre-column derivatization HPLC.The ratio of galactose was the highest in five monosaccharide,and the ratio of galactose to glucose was 1.656-4.496.In addition,crude polysaccharides of H.syriacus flowers showed potential antioxidant activity by 1,1-diphenyl-2-picrylhydrazyl radical(DPPH)assay,total reducing capacity assay and ABTS assay in vitro,and its antioxidant effect showed a good dose-effect relationship with the concentration of crude polysaccharides.Among the tested varieties,polysaccharides of pink multiple petals flower and white multiple petals flower had the same molecular masses and monosaccharides composition,but the antioxidant activity of the polysaccharides of pink multiple petals flower was higher than that of the white flowers.The results of this study can provide a theoretical basis for the application of H.syriacus flower in the field of functional foods.

[Analysis of chemical components in Cordyceps by online gradient extraction-HPLC].

Online gradient extraction-high performance liquid chromatography( HPLC) method was developed for simultaneous determination of high and low polar components in Cordyceps. The sample powder of Cordyceps was uniformly mixed with diatomaceous earth,packed into extraction tank,and installed into the HPLC system. Online gradient extraction was conducted with mobile phase at 70 ℃. The separation was performed on Zorbax SB-AQ( 4. 6 mm×150 mm,5 µm) column with 0. 1% formic acid solution-methanol as the mobile phase for gradient elution at 1. 0 mL·min~(-1). The column temperature was 30 ℃,and detection wavelength was set at 260 nm. The results showed that the high and low polar components in Cordyceps could be simultaneously extracted and separated by the developed method. Meanwhile,six high polar compounds( uracil,uridine,thymine,inosine,guanosine and adenosine) and one low polar compound( ergosterol) were identified by comparison with the reference peaks. The established method is rapid,stable and environment friendly,which is helpful to improve the quality evaluation level for Cordyceps.

[Effects of different drying conditions on protein in Cordyceps].

In this study,the protein in different Cordyceps samples,which include fresh sample( S1),22 ℃ drying sample( S2),37 ℃ drying sample( S3) and 60 ℃ drying sample( S4),were analyzed by sodium dodecylsupinate-polyacrylamide gel electrophoresis( SDS-PAGE) and two-dimensional electrophoresis( 2-DE). The total protein contents in Cordyceps samples were from 1. 655-4. 493 mg·g~(-1) and the protein contents in fresh sample was the highest. The results of SDS-PAGE showed that the mainly ranges of protein molecular weight of Cordyces samples were 10-100 kDa and the numbers of protein bands were 28 to 41,the fresh sample had the maximum number of protein bands. The 2-DE profiles were analyzed by PDQuest software. The resulted indicated that 488-876 protein spots were detected in different Cordyceps samples and the isoelectric point( pI) was distributed between 4. 5 and 6. 5,the protein molecular weight was distributed in 10-20 kDa and 25-100 kDa,the fresh sample had the maximum number of protein spots. Therefore,the drying process could decrease contents and species of protein in Cordyceps,and the different drying conditions had different effects on protein. These results provide a reference for improving the drying process of Cordyceps.

Circular Array of Magnetic Sensors for Current Measurement: Analysis for Error Caused by Position of Conductor.

This paper analyzes the measurement error, caused by the position of the current-carrying conductor, of a circular array of magnetic sensors for current measurement. The circular array of magnetic sensors is an effective approach for AC or DC non-contact measurement, as it is low-cost, light-weight, has a large linear range, wide bandwidth, and low noise. Especially, it has been claimed that such structure has excellent reduction ability for errors caused by the position of the current-carrying conductor, crosstalk current interference, shape of the conduction cross-section, and the Earth's magnetic field. However, the positions of the current-carrying conductor-including un-centeredness and un-perpendicularity-have not been analyzed in detail until now. In this paper, for the purpose of having minimum measurement error, a theoretical analysis has been proposed based on vector inner and exterior product. In the presented mathematical model of relative error, the un-center offset distance, the un-perpendicular angle, the radius of the circle, and the number of magnetic sensors are expressed in one equation. The comparison of the relative error caused by the position of the current-carrying conductor between four and eight sensors is conducted. Tunnel magnetoresistance (TMR) sensors are used in the experimental prototype to verify the mathematical model. The analysis results can be the reference to design the details of the circular array of magnetic sensors for current measurement in practical situations.

[Analysis on stability and antioxidant capacity of color-related components from Dendrobium officinale flower].

The study is aimed to fully analyze antioxidant activty and stability of color-related components from Dendrobium officinale flower. The contents of anthocyanins,carotenoids and flavonoids of 10 varieties including whole flower and labellum of D.officinale flower were detected using UV visible spectroscopy technique and evaluated for their 1,1-diphenyl-2-picrylhydrazyl radical (DPPH·), superoxide anion radical (·O⁻2) and hydroxy radical (·OH) scavenging activty. And the effects of 4 kinds of metal ions (Cu²âº, Mg²âº, Al³âº,K⁺) and 2 kinds of food additives were investigated on the stability of anthocyanins pigment from D.officinale flower. The results indicated that the flower of D.officinale contained anthocyanins,carotenoids and flavonoids,and their contents in different parts of different families varied. The content of anthocyanins (1 330.9 µg·g⁻¹) in labellum was significantly higher than that in the whole flower (696.3 µg·g⁻¹). The content of carotenoids was positively correlated with the content of anthocyanins,and there was significant positive correlation between the scavenging capacities of the three free radicals and the contents of anthocyanin,respectively (0.415,0.384,0.455). The Cu²âº, Mg²âº, Al³âº, K⁺ and glucose showed significant color-enhancing effect and could increase the stability of anthocyanin in D.officinale flower,while ascorbic acids showed remarkably degradation effect of anthocyanin in D.officinale flower.