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BACKGROUND As more attention is paid to selenium-rich products, the research on the determination of selenium content in crops has become more and more significant. However, existing methods for determining organic selenium has interferences of the matrix effect and polyatomic ion, which affect the accuracy of the measurement. OBJECTIVES To establish a rapid method to determine selenium species pf organic selenium in agricultural products by liquid chromatography-quadrupole/electrostatic field orbitrap high-resolution mass spectrometry (LC-Q Exactive Orbitrap MS). METHODS The selenium species were extracted using an ultrasonic extraction system with a mixture of protease XIV. The separation was carried out on a Waters Symmetry RP18 column by gradient elution with water and acetonitrile as mobile phases. The selenomethionine, selenocystine and methylselenocysteine were simultaneously analyzed in switching positive and negative modes. The quantitative and qualitative analyses were carried out by high-resolution mass spectrometry with electrospray ionization (ESI) source in negative ion acquisition mode under Full MS/dd-MS2 mode. RESULTS Under the optimal conditions, good linearity was obtained in the respective concentration ranges. The limits of detection for three compounds were in the range of 1.0-4.7μg/kg. The recoveries ranged from 76.4% to 116.0% with relative standard deviations less than 6.5%. CONCLUSIONS Compared with existing methods, this method has a wider linear range and is suitable for the analysis of a variety of grain and vegetable samples. The established method has been applied to the determination of the edible part of a variety of crops in Heilongjiang, which is the main grain production area in China. The results show that selenomethionine is the main ingredient in cereals, and methylselenocysteine is the main ingredient in vegetables, and that the organic selenium content of crops in this area is at a low level. Therefore, selenium supplementation is urgently needed.

BACKGROUND Heavy metal pollution caused by the exploitation of mineral resources in the social development has caused serious threats to the ecosystem and human health. Hyperaccumulating plants have super-enrichment and super-tolerance capabilities for heavy metals, which is an effective way to reduce environmental heavy metal pollution, protect human health, and realize green mineral exploration. It has been widely used in phytoremediation, plant mining and plant prospecting. OBJECTIVES To better understand the enrichment and tolerance mechanisms of hyperaccumulating plants, reveal the principles of heavy metal-plant interactions, and improve the ability of plants to accumulate heavy metals. METHODS Based on a brief description of the effects of heavy metals on plants, the focus of this article is the accumulation mechanism of heavy metal hyperaccumulation plants, and a review of the progress in the fields of detoxification and tolerance mechanisms. RESULTS (1) The root exudates of hyperaccumulator and microorganisms work together to promote the dissolution of heavy metals. After being absorbed by the symplastic and apoplastic pathways, the heavy metals are transported upwards to aerial parts through xylem, and segregated in vacuoles, achieving the hyperaccumulation of heavy metals. (2) Concentration of free metal ions in cytoplasm can be reduced by combining heavy metals with small molecular organic acids, cell walls, phytochelatins and vacuole isolation, which increases plant tolerance. (3) Under heavy metal stress, plants activate a variety of specific antioxidant enzymes to resist oxidative stress and achieve hypertolerance on heavy metals. (4) A possible mechanism is suggested that arsenic-induced oxidative stress in plants should be composed of arsenic reduction and methylation, and Haber-Weiss reaction. CONCLUSIONS In-depth research on the physiological and biochemical processes involved in hyperaccumulation and hypertolerance of hyperaccumulator reveals key factors and related principles. Finding effective ways to improve their specific accumulation and indication capabilities will contribute to the research and application of hyperaccumulators to develop in depth.

BACKGROUND Rice is the staple food of about half of the world's population, and the dependence of Asian staple food on rice exceeds 90%. There are varying degrees of arsenic (As) pollution all over the world. As can accumulate in rice and enter the human body, causing health problems. OBJECTIVES To reveal the mechanism of As absorption in rice. METHODS The content and species characteristics of As absorbed by rice and the species analysis techniques were reviewed. The mechanisms of As absorption, tolerance and detoxification by rice were summarized. RESULTS The content of As in rice ranged from a few to several hundred ng/g. The process of As entering the rice from the soil involved complex physical and chemical changes and species transformation. Arsenic mainly existed in the form of arsenate, arsenite, thiol and methyl coordination in rice. Field water management, fertilization and soil amendments controlled the absorption of As in rice. Each technique had their advantages and disadvantages. Soil pH, redox conditions, organic matter and coexisting elements were the key factors affecting As absorption by rice. Agronomic methods can control the absorption of As by rice. Many factors such as arsenic biogeochemistry and the absorption and metabolism of arsenic in rice agroecosystems affect the concentration of arsenic in rice and grain. Comprehensive consideration of the effects of agronomic activities on soil pH, redox conditions, organic matter structure and coexisting elements, and different geographic factors such as soil characteristics and economic factors were the keys to realize the control of arsenic absorption by rice in production practice. CONCLUSIONS Comprehensive use of multiple agronomic methods for rice farming is an important way to control the absorption of arsenic in rice in the future. Application of new agronomic methods in the control of arsenic absorption by rice, the impact of climate change on arsenic absorption by rice, and application of non-destructive in situ and in vivo analysis techniques for As speciation analysis, are keys for more scientifically and effectively controlling the arsenic content in rice and reducing the risk of human As exposure on the global scale in the future. These are also the key development directions and challenges in the future.

BACKGROUND Persistent organic pollutants (POPs), pharmaceuticals, personal care products (PPCPs) and disinfection by products (DBPs) have raised significant concerns for their potential ecological threat to the environment and human health. Research on their source, detection method, environmental distribution, migration and transformation has become the hot topic. OBJECTIVES To introduce recent analytical techniques and applications for the determination of POPs, PPCPs and DBPs in environmental and biota samples, and summarize the extraction, separation and instrumental analyses of the halogenated emerging organic pollutants. To discuss future trends for improving the POPs, PPCPs and DBPs analyses and potential emerging organic pollutants. METHODS In recent years the analytical techniques for emerging organic pollutants have made great progress. According to the nature of samples, a variety of extraction methods have been used, such as accelerated solvent extraction and solid phase microextraction. Effective clean-up steps include GPC, multi-layer column and SPE. Conventional analytical methods of emerging organic pollutants have been based mainly on GC-ECD. With the fast development of chromatography and mass spectrometry, congener-specific analysis has become a mainstream method. The analysis of certain emerging organic pollutants at trace levels is now a routine due to the advancement of HRGC-HRMS. RESULTS Methods for the analysis of emerging organic pollutants in a variety of environmental, biota and food matrices have been well developed during the past several decades. However, the analytical challenge still remains for a direct analysis of emerging pollutants. For example, short chain chlorinated paraffin has more than 7000 kinds of congeners. The traditional analytical methods cannot achieve their separation, and accurate qualitative and quantitative analysis of these pollutants is challenging. CONCLUSIONS The analytical technique for emerging organic pollutants still has a long way to go. On the one hand, it is necessary to explore effective pretreatment techniques such as magnetic solid-phase matrix dispersion extraction technology to reduce the possible interference. On the other hand, it is necessary to improve the recognition, sensitivity, accuracy and practicability of chromatographic mass spectrometry techniques such as comprehensive Two-dimensional Gas Chromatography and Fourier Transform Mass Spectrometry and develop a simple and standard quantitative method.

This article introduces the design of symmetrical approximately shift-invariant fractional overcomplete wavelet transforms. First, a design scheme for the symmetrical low-pass filter with minimum-length was proposed, and then the corresponding highpass filters with approximately shift-invariant properties were constructed via Toeplitz matrix factorization, which has a lower computational complexity than other methods. In addition, fractional overcomplete wavelet transforms could he designed with higher vanishing moments through the method proposed. Subsequently, a bearing fault diagnosis scheme was proposed using the symmetrical shiftinvariant fractional overcomplete wavelet transforms. Experimental results show that the bearing faults can be detected effectively using the symmetrical shift-invariant fractional overcomplete wavelet transforms.

Yao An Shen,1,* Ing Luen Shyu,2,* Maggie Lu,3 Chun Lin He,4 Yen Mei Hsu,2 Hsiang Fa Liang,3 Chih Peng Liu,3 Ren Shyan Liu,5,6 Biing Jiun Shen,7 Yau Huei Wei,1 Chi Mu Chuang2,4 1Institute of Biochemistry and Molecular Biology, School of Life Sciences, 2Institute of Clinical Medicine, School of Medicine, National Yang-Ming University, Taipei, 3Biomedical Technology and Device Research Laboratories, Industrial Technology Research Institute, Hsinchu, 4Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, Taipei Veterans General Hospital, 5Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, 6National PET/Cyclotron Center, Taipei Veterans General Hospital, Taipei, Taiwan; 7Division of Psychology, Nanyang Technological University, Singapore *These authors contributed equally to the work Abstract: The current enhanced permeability and retention (EPR)-based approved nanomedicines have had little impact in terms of prolongation of overall survival in patients with cancer. For example, the two Phase III trials comparing Doxil®, the first nanomedicine approved by the US Food and Drug Administration, with free doxorubicin did not find an actual translation of the EPR effect into a statistically significant increase in overall survival but did show less cardiotoxicity. In the current work, we used a two-factor factorial experimental design with intraperitoneal versus intravenous delivery and nanomedicine versus free drug as factors to test our hypothesis that regional (intraperitoneal) delivery of nanomedicine may better increase survival when compared with systemic delivery. In this study, we demonstrate that bypassing, rather than exploiting, the EPR effect via intraperitoneal delivery of nanomedicine harboring a sustained-release function demonstrates dual pharmacokinetic advantages, producing more efficient tumor control and suppressing the expression of stemness markers, epithelial-mesenchymal transition, angiogenesis signals, and multidrug resistance in the tumor microenvironment. Metastases to vital organs (eg, lung, liver, and lymphatic system) are also better controlled by intraperitoneal delivery of nanomedicine than by standard systemic delivery of the corresponding free drug. Moreover, the intraperitoneal delivery of nanomedicine has the potential to replace hyperthermic intraperitoneal chemotherapy because it shows equal efficacy and lower toxicity. In terms of efficacy, exploiting the EPR effect may not be the best approach for developing a nanomedicine. Because intraperitoneal chemotherapy is a type of regional chemotherapy, the pharmaceutical industry might consider the regional delivery of nanomedicine as a valid alternative pathway to develop their nanomedicine(s) with the goal of better tumor control in the future. Keywords: enhanced permeability and retention effect, liposome, paclitaxel, ovarian cancer

Due to the wide presence of nanoparticles (NPs) and heavy metals (HMs) in the environment, especially in porous media like soil, their fate and transport behaviors and hence the environmental impacts will greatly depend on their speciation, the impacts of natural organic matter (NOM) and how they interact with each other. Most correlative studies select typical NPs, HMs and NOM as the model subjects and conduct a series of adsorption-desorption batch experiments and NPs-HMs co-transport experiments in porous media to systematically study the NPs-HMs co-behaviors. Both thermodynamic and kinetics models have been applied to describe the interfacial reaction and transport/retention data obtained from experiments. The parameters were well compared, simulated and interpreted in order to achieve a complete picture of the effects of NOM on the fate of NPs-HMs. To reveal the mechanisms of NPs surface adsorption and the metal ions immobilization by NPs between soil grains, a big series of characterization analysis methods can be employed, such as Transmission Electron Microscopy (TEM), X-ray Diffractomer (XRD), X-ray Photoelectron Spectrometer (XPS), Fourier Transform Infrared Spectrometry (FTIR) and X-ray Absorption Near Edge Structure Spectrometry/Extended X-ray Absorption Fine Structure Spectrometry(XANES/EXAFS). Some of these methods working together are believed as a very effective and efficient approach in modern study. Understanding how the NPs impact on the leachability and bioavailability of heavy metals in subsurface porous media is of fundamental importance to the accurate assessment of environmental and ecological impacts of NPs. The results also have great significance to well comprehend the mechanisms of nano soil remediation.

For the problem of harmonic pollution of underground power network caused by existing mine-used three-phase power supply, a mine-used digital three-phase power supply based on STM32F103VB was designed and working principle and control strategies of the power supply were introduced in details. A typical AC-DC-AC structure is adopted in the power supply. The voltage-current dual closed loops direct current control strategy is used in PWM rectifier to make input current and input voltage in phase, input current in sine and output voltage in stabilization. The dual closed loops control strategy of outer voltage loop and inner current loop is used in PWM inverter to improve quality of the output voltage waveform and load adaptability. SPWM wave is generated through underflow interruption of TIM1 of STM32F103VB.The experimental results showed that the power supply has high power factor of input and high stability of output with little harmonic of input current.

Shen YA, Shyu IL, Lu M, et al. Int J Nanomedicine. 2015; 10:2485–2502.The authors advise that Figure 2B on page 2490 contains the incorrect image for the EP group. The correct Figure 2B image is shown below.Read the original article