High-Efficiency Miniaturized Ultrasonic Nebulization Sample Introduction System for Elemental Analysis of Microvolume Biological Samples by Inductively Coupled Plasma Quadrupole Mass Spectrometry.

Sensitive and high-throughput analysis of trace elements in volume-limited biological samples is highly desirable for clinical research and health risk assessments. However, the conventional pneumatic nebulization (PN) sample introduction is usually inefficient and not well-suited for this requirement. Herein, a novel high-efficiency (nearly 100% sample introduction efficiency) and low-sample-consumption introduction device was developed and successfully coupled with inductively coupled plasma quadrupole mass spectrometry (ICP-QMS). It consists of a micro-ultrasonic nebulization (MUN) component with an adjustable nebulization rate and a no-waste spray chamber designed based on fluid simulation. The proposed MUN-ICP-QMS could achieve sensitive analysis at a low sampling rate of 10 µL min-1 with an extremely low oxide ratio of 0.25% where the sensitivity is even higher comparing to PN (100 µL min-1). The characterization results indicate that the higher sensitivity of MUN is attributed to the smaller aerosol size, higher aerosol transmission efficiency, and improved ion extraction. In addition, it offers a fast washout (20 s) and reduced sample consumption (as low as 7 µL). The absolute LODs of the studied 26 elements by MUN-ICP-QMS are improved by 1-2 orders of magnitude compared with PN-ICP-QMS. The accuracy of the proposed method was validated by the analysis of human serum, urine, and food-related certified reference materials. Furthermore, preliminary results of serum samples from patients with mental illnesses demonstrated its potential in the field of metallomics.

The spatiotemporal matching pattern of Ezrin/Periaxin involved in myoblast differentiation and fusion and Charcot-Marie-Tooth disease-associated muscle atrophy.

BACKGROUND: Clinically, Charcot-Marie-Tooth disease (CMT)-associated muscle atrophy still lacks effective treatment. Deletion and mutation of L-periaxin can be involved in CMT type 4F (CMT4F) by destroying the myelin sheath form, which may be related to the inhibitory role of Ezrin in the self-association of L-periaxin. However, it is still unknown whether L-periaxin and Ezrin are independently or interactively involved in the process of muscle atrophy by affecting the function of muscle satellite cells. METHOD: A gastrocnemius muscle atrophy model was prepared to mimic CMT4F and its associated muscle atrophy by mechanical clamping of the peroneal nerve. Differentiating C2C12 myoblast cells were treated with adenovirus-mediated overexpression or knockdown of Ezrin. Then, overexpression of L-periaxin and NFATc1/c2 or knockdown of L-periaxin and NFATc3/c4 mediated by adenovirus vectors were used to confirm their role in Ezrin-mediated myoblast differentiation, myotube formation and gastrocnemius muscle repair in a peroneal nerve injury model. RNA-seq, real-time PCR, immunofluorescence staining and Western blot were used in the above observation. RESULTS: For the first time, instantaneous L-periaxin expression was highest on the 6th day, while Ezrin expression peaked on the 4th day during myoblast differentiation/fusion in vitro. In vivo transduction of adenovirus vectors carrying Ezrin, but not Periaxin, into the gastrocnemius muscle in a peroneal nerve injury model increased the numbers of muscle myosin heavy chain (MyHC) I and II type myofibers, reducing muscle atrophy and fibrosis. Local muscle injection of overexpressed Ezrin combined with incubation of knockdown L-periaxin within the injured peroneal nerve or injection of knockdown L-periaxin into peroneal nerve-injured gastrocnemius muscle not only increased the number of muscle fibers but also recovered their size to a relatively normal level in vivo. Overexpression of Ezrin promoted myoblast differentiation/fusion, inducing increased MyHC-I+ and MyHC-II + muscle fiber specialization, and the specific effects could be enhanced by the addition of adenovirus vectors for knockdown of L-periaxin by shRNA. Overexpression of L-periaxin did not alter the inhibitory effects on myoblast differentiation and fusion mediated by knockdown of Ezrin by shRNA in vitro but decreased myotube length and size. Mechanistically, overexpressing Ezrin did not alter protein kinase A gamma catalytic subunit (PKA-γ cat), protein kinase A I alpha regulatory subunit (PKA reg Iα) or PKA reg Iß levels but increased PKA-α cat and PKA reg II α levels, leading to a decreased ratio of PKA reg I/II. The PKA inhibitor H-89 remarkably abolished the effects of overexpressing-Ezrin on increased myoblast differentiation/fusion. In contrast, knockdown of Ezrin by shRNA significantly delayed myoblast differentiation/fusion accompanied by an increased PKA reg I/II ratio, and the inhibitory effects could be eliminated by the PKA reg activator N6-Bz-cAMP. Meanwhile, overexpressing Ezrin enhanced type I muscle fiber specialization, accompanied by an increase in NFATc2/c3 levels and a decrease in NFATc1 levels. Furthermore, overexpressing NFATc2 or knocking down NFATc3 reversed the inhibitory effects of Ezrin knockdown on myoblast differentiation/fusion. CONCLUSIONS: The spatiotemporal pattern of Ezrin/Periaxin expression was involved in the control of myoblast differentiation/fusion, myotube length and size, and myofiber specialization, which was related to the activated PKA-NFAT-MEF2C signaling pathway, providing a novel L-Periaxin/Ezrin joint strategy for the treatment of muscle atrophy induced by nerve injury, especially in CMT4F.

Electrothermal Desolvation-Enhanced Dielectric Barrier Discharge Plasma-Induced Vapor Generation for Sensitive Determination of Antimony by Atomic Fluorescence Spectrometry.

A novel simple electrothermal desolvation-enhanced dielectric barrier discharge plasma-induced vapor generation (ETD-DBD-PIVG) method has been developed for sensitive Sb determination by atomic fluorescence spectrometry (AFS). In our proposed ETD-DBD-PIVG, 20 µL sample solution was dried first; then, the resulting solution residue was directly converted into molecular volatile species efficiently through the interactions with hydrogen-doped DBD plasma; and finally, it was transported to AFS for detection. It was found that the desolvation process could greatly enhance Sb vapor generation, and the Sb fluorescence signal intensity is almost independent of its speciation, where comparable sensitivity is achieved for Sb(III) and Sb(V), enabling efficient total Sb detection without pre-reduction. Influencing parameters were evaluated in detail, including heating time, discharge gap, solution pH, and flow rates of argon and hydrogen, as well as coexisting ion interference. Under optimized conditions, the limit of detection was calculated as 0.86 µg L-1 (17.2 pg) for Sb. The accuracy of the proposed method was validated by the analysis of certified reference materials of simulated natural water samples and several river water samples. Compared with conventional hydride generation, the new ETD-DBD-PIVG offers an alternative green vapor generation technique with several advantages: (1) it eliminates the use of a sample flow system (e.g., no use of any syringe or peristaltic pump); instead, 20 µL of a sample is directly pipetted onto the glass plate for analysis; (2) it greatly simplifies the sample pretreatment steps as no pre-reduction process is needed; (3) it is sensitive and suitable for volume-limited sample analysis: efficient Sb vapor generation without chemical reducing reagents in ETD-DBD-PIVG enables Sb detection with an absolute limit at the picogram level. All the results demonstrate that the proposed method provides a simple, green, and sensitive method for Sb determination and it can also be extended to other elements such as Cd and As.

Direct and Sensitive Determination of Antimony in Water by Hydrogen-Doped Solution Anode Glow Discharge-Optical Emission Spectrometry Without Hydride Generation.

In the present work, a novel, simple, and sensitive method for the direct determination of trace Sb in water samples was developed based on hydrogen-doped solution anode glow discharge-optical emission spectrometry (SAGD-OES). It was found that the vapor generation and excitation of Sb occurred simultaneously in the SAGD, contributing to the significant improvement in the sensitivity of Sb as compared with normal pure He-operated SAGD or solution cathode glow discharge. Besides, the proposed hydrogen-doped SAGD-OES could be operated even at pH = 14, which could reduce the interference of coexisting ions as many metal ions could be precipitated and removed. Our results demonstrated that the proposed method offered good tolerance to the interferences of Li, Na, Ca, Mg, Fe, Ni, Mn, and Zn ions even at a concentration of 50 mg L-1. Under optimized conditions, the limit of detection of Sb was 0.85 µg L-1, which was comparable to that of microplasma sources coupled with conventional hydride generation. The linearity of the Sb calibration curve reached R2 > 0.999 in the 5-5000 µg L-1 range. Finally, the accuracy of the proposed method was validated by the determination of certified reference materials [GSB 07-1376-2001 (1) and (2))] and real water samples. The proposed low-power (6 W), green, sensitive, rapid, and robust method provides a promising approach for on-site trace Sb analysis and may also be extended to other elements.

Development of an Automatic Column Chromatography Separation Device for Metal Isotope Analysis Based on Droplet Counting.

A novel, simple, cost-effective, reliable, and practical automatic column chromatography separation device capable of simultaneously purifying samples for radiogenic and non-traditional stable isotope analysis has been developed. The device avoids the use of any pump and features eluent driving by the siphon effect (gravity) and quantitative control by infrared droplet counting. Several factors affecting the control of droplets were investigated, including types and concentrations of eluents and the height of the liquid level. Results showed that accurate dripping of the eluent could be readily achieved by controlling the number of droplets under selected conditions. The separation performance of the device was first demonstrated by the elution of Sr and Cd in synthetic matrix solutions. The recoveries of Sr and Cd samples were better than 87.6 and 95.0%, respectively, and the whole procedure blank was about 0.3 ng for Sr and 0.1 ng for Cd. Finally, the reliability of the device was further validated by the purification of Sr and Cd from different geological reference materials (NIST 2711a, Nod-A-1, BCR-2, and BHVO-2). The determined Cd and Sr isotope values agree well with their reference values within the uncertainty range. All these results clearly demonstrate the reliability and practicability of the proposed device, which provides a promising method for the automated purification of isotope samples.

Development of a Portable Method for Serum Lithium Measurement Based on Low-Cost Miniaturized Ultrasonic Nebulization Coupled with Atmospheric-Pressure Air-Sustained Discharge.

An accurate, rapid but cheap, and portable method for monitoring of serum lithium (Li) is highly desirable for mental patients who take Li medicine for treatment. Conventional techniques are usually bulky, costly, and cannot provide on-site real-time measurements. Herein, a miniaturized, reliable, cost-effective, and portable optical emission method for rapid and sensitive determination of serum Li was developed based on a combination of miniaturized ultrasonic nebulization (MUN) and a low-power (≈22 W) atmospheric-pressure air-sustained discharge (APAD) excitation source. The proposed method eliminates the use of any compressed gas or pump and can achieve serum Li detection within 40 s with low sample consumption (less than 20 µL serum). Except for dilution with water, no extra treatment is needed for serum Li analysis by MUN-APAD-OES. In addition, it offers a significant advantage of good tolerance to the coexisting high concentration of Na, K, Ca, and Mg, which is in contrast with the obvious matrix effect encountered in conventional inductively coupled plasma optical emission spectrometry (ICP-OES). Different operating parameters affecting the performance of MUN-APAD-OES were evaluated. Under optimized conditions, the detection limit of Li (670.8 nm) was calculated to be 0.6 µg L-1 (6 µg L-1 in serum). Finally, the accuracy of the proposed method was validated by the analysis of two certified reference materials (Seronorm serum L-1 and L-2 RUO), six real human serum samples, and eight real animal serum samples. All of the results indicate that the low-cost and low-power MUN-APAD-OES provides a promising reliable method for on-site serum Li measurement and may also be extended to other elements.

The detrimental effects of stress-induced glucocorticoid exposure on mouse uterine receptivity and decidualization.

Glucocorticoids (GCs), stress-induced steroid hormones, are released by adrenal cortex and essential for stress adaptation. Recently, there has been renewed interest in the relationship between GCs and pregnancy following the discovery that glucocorticoid receptor is necessary for implantation. It has been widely recognized that stress is detrimental to pregnancy. However, effects of stress-induced GC exposure on uterine receptivity and decidualization are still poorly understood. This study aims to explore the effects of GCs exposure on uterine receptivity, decidualization, and their underlying mechanisms in mice. Single prolonged stress (SPS) and corticosterone (Cort) injection models were used to analyze effects of GC exposure on early pregnancy, respectively. SPS or Cort injection inhibits embryo implantation by interfering Lif signaling and stimulating the uterine deposition of collagen types I, III, and IV on day 4 of pregnancy. Uterine decidualization is also attenuated by SPS or Cort injection through suppressing Cox-2 expression. Cort-induced collagen disorder also suppresses decidualization through regulating mesenchymal-epithelial transition. Our data should shed lights for a better understanding for the effects of GCs on embryo implantation for clinical research.

Simultaneous Sensitive Determination of Selenium, Silver, Antimony, Lead, and Bismuth in Microsamples Based on Liquid Spray Dielectric Barrier Discharge Plasma-Induced Vapor Generation.

A highly efficient liquid spray dielectric barrier discharge (LSDBD) plasma-induced vapor generation technique is developed for the simultaneous determination of selenium, silver, antimony, lead, and bismuth in liquid microsamples (20 µL) by inductively coupled plasma mass spectrometry (ICP-MS). It is demonstrated that the dissolved Se, Ag, Sb, Pb, and Bi ions in solution samples are readily and simultaneously converted to volatile species efficiently by LSDBD plasma-induced chemical processes under similar conditions. It eliminates the use of unstable and expensive reducing reagents, and only formic acid is required in the proposed LSDBD chemical vapor generation technique. It is also worth noting that this is the first report of using plasma-induced chemical processes for the vapor generation of Ag and Bi. The simultaneous sensitive determination of Se, Ag, Sb, Pb, and Bi is realized with a sample volume of only 20 µL and the sample throughput could be as high as 180 samples h-1. The limit of detection (LOD) for simultaneous determination of Se, Ag, Sb, Pb, and Bi is 10 ng L-1 (200 fg), 2 ng L-1 (40 fg), 5 ng L-1 (100 fg), 4 ng L-1 (80 fg), and 3 ng L-1 (60 fg), respectively. The precision of Se, Ag, Sb, Pb, and Bi in the present method is evaluated to be better than 4%. The utility of the proposed technique is demonstrated by the analysis of ultratrace Se, Ag, Sb, Pb, and Bi in archaea cells and single conodont samples.

Highly Sensitive Determination of Arsenic and Antimony Based on an Interrupted Gas Flow Atmospheric Pressure Glow Discharge Excitation Source.

A novel interrupted gas flow (IF) technique has been proposed for highly sensitive determination of ultratrace levels of arsenic and antimony in water samples by atmospheric pressure glow discharge (APGD) excitation source coupled with HCl-KBH4 hydride generation (HG). It is demonstrated that the gas flow interruption technique provides a dramatic and reproducible enhancement of emission signals of 1-2 orders of magnitude for As and Sb over conventional continuous gas flow (CF) in APGD. The enhanced analyte emission sensitivities in IF-APGD were investigated from the viewpoint of changes in plasma excitation temperature and analyte density. With eight As lines as the thermometric probe, no measurable change in excitation temperature was found, suggesting that the enhancement is caused by an increase in analyte number density in the plasma immediately following the gas flow interruption. Furthermore, the enhancement factor was found to increase with the time interval in between the gas interruption, supporting an analyte adsorption (or trap)-release mechanism hypothesis. Under optimized conditions, the detection limits (DLs) of IF-APGD mode for As and Sb were calculated to be 0.02 and 0.003 µg L-1, which are, respectively, about 27- and 120-fold improved compared to CF-APGD mode. The linearity of calibration for both As and Sb reached R2 > 0.999 in the 0.1-5 µg L-1 range. The accuracy of the proposed method was validated by the determination of certified reference materials (CRMs), and the results agreed well with the certified values.

Investigation of the Pressure Gain Characteristics and Cycle Performance in Gas Turbines Based on Interstage Bleeding Rotating Detonation Combustion.

To further improve the cycle performance of gas turbines, a gas turbine cycle model based on interstage bleeding rotating detonation combustion was established using methane as fuel. Combined with a series of two-dimensional numerical simulations of a rotating detonation combustor (RDC) and calculations of cycle parameters, the pressure gain characteristics and cycle performance were investigated at different compressor pressure ratios in the study. The results showed that pressure gain characteristic of interstage bleeding RDC contributed to an obvious performance improvement in the rotating detonation gas turbine cycle compared with the conventional gas turbine cycle. The decrease of compressor pressure ratio had a positive influence on the performance improvement in the rotating detonation gas turbine cycle. With the decrease of compressor pressure ratio, the pressurization ratio of the RDC increased and finally made the power generation and cycle efficiency enhancement rates display uptrends. Under the calculated conditions, the pressurization ratios of RDC were all higher than 1.77, the decreases of turbine inlet total temperature were all more than 19 K, the power generation enhancements were all beyond 400 kW and the cycle efficiency enhancement rates were all greater than 6.72%.

Generation of Volatile Cadmium and Zinc Species Based on Solution Anode Glow Discharge Induced Plasma Electrochemical Processes.

In this study, a novel high efficiency vapor generation strategy was proposed on the basis of solution anode glow discharge for the determination of Cd and Zn by atomic fluorescence spectrometry. In this approach, a glow discharge microplasma was acted as a gaseous cathode to initiate the plasma electrochemical vapor generation of Cd and Zn. Cadmium/zinc ions could be converted into molecular species efficiently at the plasma-liquid interface from a supporting electrolyte (HCl, pH = 3.2). It was found that the overall efficiency of the plasma electrochemical vapor generation (PEVG) system was much higher than the conventional electrochemical hydride generation (EcHG) and HCl-KBH4 system. With no requirement for other reducing reagents, this new approach enabled us to detect Cd and Zn with detection limits as low as 0.003 µg L-1 for Cd and 0.3 µg L-1 for Zn. Good repeatability (relative standard deviation (RSD), n = 5) was 2.4% for Cd (0.1 µg L-1) and 1.7% for Zn (10 µg L-1) standard. The accuracy of the proposed method was successfully validated through analysis of cadmium in reference material of stream sediment (GBW07311), soil (GBW07401), rice (GBW10045), and zinc in a simulated water sample (GSB 07-1184-2000). Replacing a metal electrode with a plasma offers the advantage of eliminating potential interactions between the species in liquid and the electrode, which solves the issues associated with electrode encountered in conventional EcHG. The ability to initiate electrochemical vapor generation reactions at the plasma-liquid interface opens a new approach for chemical vapor generation based on interactions between plasma gas-phase electrons and solutions.

Battery-Operated Atomic Emission Analyzer for Waterborne Arsenic Based on Atmospheric Pressure Glow Discharge Excitation Source.

In this paper, a sensitive atomic emission spectrometer (AES) based on a new low power and low argon consumption (<8 W, 100 mL min-1) miniature direct current (dc) atmospheric pressure glow discharge (APGD) plasma (3 mm × 5 mm) excitation source was developed for the determination of arsenic in water samples. In this method, arsenic in water was reduced to AsH3 by hydride generation (HG), which was then transported to the APGD source for excitation and detected by a compact CCD (charge-coupled device) microspectrometer. Different parameters affecting the APGD and the hydride generation reactions were investigated. The detection limit for arsenic with the proposed APGD-AES was 0.25 µg L-1, and the calibration curves were found to be linear up to 3 orders of magnitude. The proposed method was successfully applied to the determination of certified reference material (GBW08605), tap water, pond water, groundwater, and hot spring samples. Measurements from the APGD analyzer showed good agreement with the certified value/values obtained with well-established hydride generation atomic fluorescence spectrometry (HG-AFS). These results suggest that the developed robust, cost-effective, and fast analyzer can be used for field based arsenic determination and may provide an important tool for arsenic contamination and remediation programs.

Liquid Spray Dielectric Barrier Discharge Induced Plasma-Chemical Vapor Generation for the Determination of Lead by ICPMS.

In the present study, a novel and sensitive liquid spray dielectric barrier discharge induced plasma-chemical vapor generation technique (LSDBD-CVG) is developed for the determination of lead concentration by inductively coupled plasma mass spectrometry (ICPMS). The dissolved Pb2+ is readily converted to volatile species by LSDBD plasma induced chemical processes in the presence of 5% (v/v) formic acid in a supporting electrolyte (HCl, 0.01 mol L-1). In this LSDBD approach, the sample solution is converted to aerosol and simultaneously mixed with the DBD plasma generated at the nozzle of a pneumatic nebulizer, which greatly facilitates Pb vapor generation because of the enhanced interaction of sprayed analytes and the plasma. Optimal conditions for LSDBD-CVG were identified, and the interference effects from other metal ions were assessed. Under optimized conditions, the detection limit of Pb was found to be 0.003 µg L-1. The repeatability, expressed as the relative standard deviation (RSD) of the peak height, for the five replicate measurements of 0.03 and 1 µg L-1 lead standard, were 2.1% and 1.7%, respectively. Compared with other vapor generation methods, this new LSDBD-CVG offers several advantages including no requirement of unstable reagents, fast response, and easy coupling with flow injection, along with high tolerance for coexisting ions. The accuracy of the proposed method is demonstrated by successful analysis of Pb in reference material of stream sediment (GBW07311), soil (GBW07403), basalt (BCR-2), and simulated water sample (GBW08601). The proposed LSDBD-CVG extends the scope of elements accessible by plasma-CVG and provides an alternative efficient green approach for the vapor generation of Pb.

Investigation on a laser-assisted radiation thermometry technique.

A laser-assisted radiation thermometry (LART) technique is proposed for the surface temperature measurement of objects at high temperatures, which obviates the need for the knowledge of specimen emissivity. It uses a modulated laser to excite a temperature rise at the specimen surface, which is remotely sensed through thermal radiation detection at two infrared wavelengths. The theoretical analysis indicates that the surface temperature of the specimen can be inferred from the detected signals, independently of specimen emissivity. Measurements were performed on an oxidized Inconel 600 sample over a temperature range of 1120-1265 K. Measured surface temperatures were compared with those deduced from thermocouple measurements made inside the sample, and indicated less than 3% differences between them for sample surface temperatures above 1200 K.

Dielectric barrier discharge for high efficiency plasma-chemical vapor generation of cadmium.

A novel approach for Cd vapor generation was developed on the basis of a plasma-assisted chemical process. The generated Cd vapor was subsequently measured by atomic fluorescence spectrometry. Dissolved Cd species were readily converted into volatile species by reaction with hydrogen in a coaxial thin-film dielectric barrier discharge (DBD) plasma reactor. Both atomic and molecular Cd species were produced when a solution containing Cd(2+) was exposed to hydrogen-containing DBD plasma. Fast and efficient vapor generation of Cd was achieved simply in plain (neutral) water medium. Optimal conditions for the DBD-plasma Cd vapor generator were identified. The performance of this thin-film DBD plasma-chemical vapor generation (CVG) was evaluated through comparison with that arising from the conventional HCl-KBH4 system. The vapor generation efficiency of the proposed method (He-DBD) was found to be superior to the conventional CVG approach. Under the optimized conditions, the detection limits of Cd were found to be from 0.03 ng mL(-1) (Ar-DBD) to 0.008 ng mL(-1) (He-DBD) with a heated quartz tube atomizer (QTA); good repeatability (relative standard deviation (RSD) = 1.4%, n = 5) was obtained for a 1 ng mL(-1) standard. The new thin-film DBD plasma-CVG provides several additional advantages including simple setup, easy coupling with flow injection, low power consumption (≤18 W), cost-effectiveness, and long operation lifetime. The accuracy of the proposed method was validated through analysis of cadmium in reference material of simulated natural water sample GBW(E)080402 and rice reference material GBW10045. The concentration of cadmium determined by the present method agreed well with the reference values.

"Is this blueberry ripe?": a blueberry ripeness detection algorithm for use on picking robots.

Blueberries are grown worldwide because of their high nutritional value; however, manual picking is difficult, and expert pickers are scarce. To meet the real needs of the market, picking robots that can identify the ripeness of blueberries are increasingly being used to replace manual operators. However, they struggle to accurately identify the ripeness of blueberries because of the heavy shading between the fruits and the small size of the fruit. This makes it difficult to obtain sufficient information on characteristics; and the disturbances caused by environmental changes remain unsolved. Additionally, the picking robot has limited computational power for running complex algorithms. To address these issues, we propose a new YOLO-based algorithm to detect the ripeness of blueberry fruits. The algorithm improves the structure of YOLOv5x. We replaced the fully connected layer with a one-dimensional convolution and also replaced the high-latitude convolution with a null convolution based on the structure of CBAM, and finally obtained a lightweight CBAM structure with efficient attention-guiding capability (Little-CBAM), which we embedded into MobileNetv3 while replacing the original backbone structure with the improved MobileNetv3. We expanded the original three-layer neck path by one to create a larger-scale detection layer leading from the backbone network. We added a multi-scale fusion module to the channel attention mechanism to build a multi-method feature extractor (MSSENet) and then embedded the designed channel attention module into the head network, which can significantly enhance the feature representation capability of the small target detection network and the anti-interference capability of the algorithm. Considering that these improvements will significantly extend the training time of the algorithm, we used EIOU_Loss instead of CIOU_Loss, whereas the k-means++ algorithm was used to cluster the detection frames such that the generated predefined anchor frames are better adapted to the scale of the blueberries. The algorithm in this study achieved a final mAP of 78.3% on the PC terminal, which was 9% higher than that of YOLOv5x, and the FPS was 2.1 times higher than that of YOLOv5x. By translating the algorithm into a picking robot, the algorithm in this study ran at 47 FPS and achieved real-time detection well beyond that achieved manually.

Effect of Exergame Intervention on Balance Ability of Adolescents: A Randomized Controlled Trial.

Objective: Balance is a strong indicator of physical development of adolescents, and there is a trend of employing exergame for balance training. However, the effectiveness of exergame specifically designed for balance training on adolescents' balance abilities in various postures remains unclear. Materials and Methods: In this study, an exergame for balance training was developed with Kinect and a randomized controlled trial was conducted to assess its effect on balance ability development. Thirty-two healthy adolescents (age: 11.44 ± 0.51) were recruited to participate in an 8-week trial and randomly allocated to an exergame group (N = 16) or control group (N = 16). Results: The static balance test in the eagle stance posture and the dynamic balance test using the Y-Balance Test were both conducted before and after the intervention. From the results of Mann-Whitney U test, the intervention group presented greater improvement during the eagle stance test with eyes closed than the control group with P = 0.009 and P = 0.03 in left and right leg, respectively. The intervention group also showed a more significant improvement in dynamic balance (P = 0.002), which was reflected by the higher increase of composite scores. Furthermore, the balance ability when standing with nondominant leg or eyes closed, both presented higher improvements than standing with dominant leg or eyes opened, respectively. Moreover, 75% participants reported high interest and 87.5% participants expressed high engagement with exergame (score ≥4) using 5-score scale questionnaire. Conclusion: The proposed exergame for balance training could potentially promote balance training and serve as an educational tool for healthy adolescents to enhance their balance abilities.

Ultraviolet assisted liquid spray dielectric barrier discharge plasma-induced vapor generation for sensitive determination of arsenic by atomic fluorescence spectrometry.

In this study, a novel sensitive method for As determination by atomic fluorescence spectrometry was developed based on UV-assisted liquid spray dielectric barrier discharge (UV-LSDBD) plasma-induced vapor generation. It was found that prior-UV irradiation greatly facilitates As vapor generation in LSDBD likely because of the increased generation of active substances and the formation of As intermediates with UV irradiation. The experimental conditions affecting the UV and LSDBD processes (such as formic acid concentration, irradiation time, the flow rates of sample, argon and hydrogen) were optimized in detail. Under the optimum conditions, As signal measured by LSDBD can be enhanced by about 16 times with UV irradiation. Furthermore, UV-LSDBD also offers much better tolerance to coexisting ions. The limit of detection was calculated to be 0.13 µg L-1 for As, and the relative standard deviation of the repeated measurements was 3.2% (n = 7). The accuracy and effectiveness of this new method were further verified by the analysis of simulated natural water reference sample and real water samples. In this work, UV irradiation was utilized for the first time as an enhancement strategy for PIVG, which opens a new approach for developing green and efficient vapor generation methods.

Continuous exposure to isoprenaline reduced myotube size by delaying myoblast differentiation and fusion through the NFAT-MEF2C signaling pathway.

We aimed to explore whether superfluous sympathetic activity affects myoblast differentiation, fusion, and myofiber types using a continuous single-dose isoprenaline exposure model in vitro and to further confirm the role of distinct NFATs in ISO-mediated effects. Compared with delivery of single and interval single, continuous single-dose ISO most obviously diminished myotube size while postponing myoblast differentiation/fusion in a time- and dose-dependent pattern, accompanied by an apparent decrease in nuclear NFATc1/c2 levels and a slight increase in nuclear NFATc3/c4 levels. Overexpression of NFATc1 or NFATc2, particularly NFATc1, markedly abolished the inhibitory effects of ISO on myoblast differentiation/fusion, myotube size and Myh7 expression, which was attributed to a remarkable increase in the nuclear NFATc1/c2 levels and a reduction in the nuclear NFATc4 levels and the associated increase in the numbers of MyoG and MEF2C positive nuclei within more than 3 nuclei myotubes, especially in MEF2C. Moreover, knockdown of NFATc3 by shRNA did not alter the inhibitory effect of ISO on myoblast differentiation/fusion or myotube size but partially recovered the expression of Myh7, which was related to the slightly increased nuclear levels of NFATc1/c2, MyoG and MEF2C. Knockdown of NFATc4 by shRNA prominently increased the number of MyHC +, MyoG or MEF2C + myoblast cells with 1 ~ 2 nuclei, causing fewer numbers and smaller myotube sizes. However, NFATc4 knockdown further deteriorated the effects of ISO on myoblast fusion and myotube size, with more than 5 nuclei and Myh1/2/4 expression, which was associated with a decrease in nuclear NFATc2/c3 levels. Therefore, ISO inhibited myoblast differentiation/fusion and myotube size through the NFAT-MyoG-MEF2C signaling pathway.

Plasma jet desorption atomization-atomic fluorescence spectrometry and its application to mercury speciation by coupling with thin layer chromatography.

A novel plasma jet desorption atomization (PJDA) source was developed for atomic fluorescence spectrometry (AFS) and coupled on line with thin layer chromatography (TLC) for mercury speciation. An argon dielectric barrier discharge plasma jet, which is generated inside a 300 µm quartz capillary, interacts directly with the sample being analyzed and is found to desorb and atomize surface mercury species rapidly. The effectiveness of this PJDA surface sampling technique was demonstrated by measuring AFS signals of inorganic Hg(2+), methylmercury (MeHg), and phenylmercury (PhHg) deposited directly on TLC plate. The detection limits of the proposed PJDA-AFS method for inorganic Hg(2+), MeHg, and PhHg were 0.51, 0.29, and 0.34 pg, respectively, and repeatability was 4.7%, 2.2%, and 4.3% for 10 pg Hg(2+), MeHg, and PhHg. The proposed PJDA-AFS was also successfully coupled to TLC for mercury speciation. Under optimized conditions, the measurements of mercury dithizonate (Hg-D), methylmercury dithizonate (MeHg-D), and phenylmercury dithizonate (PhHg-D) could be achieved within 3 min with detection limits as low as 8.7 pg. The combination of TLC with PJDA-AFS provides a simple, cost-effective, relatively high-throughput way for mercury speciation.