Direct introduction of liquid sample into a microplasma for analytical atomic spectrometry can be a problem for its lowered atomization/excitation capability or can even extinguish it. The low power dielectric barrier discharge (DBD) microplasma has been widely used in optical spectrometry, but the number of detectable elements by atomic emission spectrometry (AES) is very limited, partially for the same reason. Here we use electrothermally vaporized analyte-containing species for sample introduction into a DBD microplasma, together with simple heating of the DBD, to enhance its atomization/excitation capability for AES. A compact tungsten coil electrothermal vaporizer (W-coil ETV) was used in this work, onto which a tiny volume of liquid sample was pipetted. Through administrating the heating program for the W-coil, sample solvent and matrix were removed first and subsequently atomized/vaporized analyte with extra energy provided by the W-coil was swept directly into the DBD microplasma for further atomization/excitation. These significantly contribute the stability of the DBD microplasma and save its power for reatomization/excitation of analyte thus improving the detectability. Under optimized experimental conditions, limits of detection of 0.8 μg L(-1) (0.008 ng) for cadmium and 24 μg L(-1) (0.24 ng) for zinc were obtained, with relative standard deviation (RSD) of 3.2% for 5 μg L(-1) Cd and 3.7% for 100 μg L(-1) Zn. Its potential application was also demonstrated by successfully analyzing several Certified Reference Materials. Its characteristics including compactness, low power consumption, cost effectiveness, tiny sample requirement, and easy operation make it very promising for field analytical chemistry.
Scope To assess the existing evidence of associations between consumption of soy and isoflavone and multiple health outcomes. Methods and results This is an umbrella review of meta‐analyses and systematic reviews of randomized trials and observational studies in humans. 114 Meta‐analyses and systematic reviews are identified with 43 unique outcomes. Soy and isoflavone consumption seems more beneficial than harmful for a series of health outcomes. Beneficial associations are identified for cancers, cardiovascular disease, gynecological, metabolic, musculoskeletal, endocrine, neurological, and renal outcomes, particularly in perimenopausal women. Harmful association is only found for gastric cancer (RR: 1.17, 95% CI: 1.02–1.36) for high intake of miso soup (1–5 cups per day) in male. Conclusion Generally, soy and isoflavone consumption is more beneficial than harmful. The results herein support promoting soy intake as part of a healthy diet. Randomized controlled trials are necessary to confirm this finding.
Non-coding RNAs (ncRNAs) have been defined as a class of RNA molecules transcribed from the genome but not encoding proteins, such as microRNAs, long non-coding RNAs, Circular RNAs, and Piwi-interacting RNAs. Accumulating evidence has recently been revealing that ncRNAs become potential druggable targets for regulation of several small-molecule compounds, based on their complex spatial structures and biological functions in cancer therapy. Thus, in this review, we focus on summarizing some new emerging designing strategies, such as high-throughput screening approach, small-molecule microarray approach, structure-based designing approach, phenotypic screening approach, fragment-based designing approach, and pharmacological validation approach. Based on the above-mentioned approaches, a series of representative small-molecule compounds, including Bisphenol-A, Mitoxantrone and Enoxacin have been demonstrated to modulate or selectively target ncRNAs in different types of human cancers. Collectively, these inspiring findings would provide a clue on developing more novel avenues for pharmacological modulations of ncRNAs with small-molecule drugs for future cancer therapeutics.
In this article, the Poincare-Lighthill-Kuo (PLK) method is used to derive an analytical expression on the stability boundary and the ion trajectory. A multipole superposition model mainly including octopole component is adopted to represent the inhomogeneities of the field. In this method, both the motional displacement and secular frequency of ions have been expanded to asymptotic series by the scale of nonlinear term , which represents a weak octopole field. By solving the zero and first-order approximate equations, it is found that a frequency shift exists between the ideal and nonlinear conditions. The motional frequency of ions in nonlinear ion trap depends on not only Mathieu parameters, a and q, but also the percentage of the nonlinear field and the initial amplitude of ions. In the same trap, ions have the same mass-to-charge ratio (m/z) but they have different initial amplitudes or velocities. Consequently, they will be ejected at different time through after a mass-selective instability scan. The influences on the mass resolution in quadrupole ion trap, which is coupled with positive or negative octopole fields, have been discussed respectively. where u is the related motional frequency in the axial and radial direction, ⍀ is the frequency of the driven radio-frequency (rf) potential,  u is a parameter dependent on Mathieu parameters a u and q u , and the subscript u refers to axial and radial coordinates. Boundary ejection methods take the advantage of ejecting ions with a mass-selective instability scan, with which the rf amplitude is scanned linearly to cause the secular frequency of ions to increase until they become unstable [2-4], when the ions reach the boundary at a ϭ 0, q eject ϭ 0.908,  z is equal to one, the ion has reached its stability limit. When a buffer gas was first used to improve the resolution of the mass spectrum by Stafford et al. [4], the stability boundary would move towards the positive direction on q-axis as bath gas pressure increase [2,5,6]. For the particle under the background at about 40 mTorr, the delay ejection also occurred at a large q value in the audio-frequency ion trap mass spectrometer [7][8][9][10][11].In practical traps, however, the electric field distribution is nonlinear, and the main causes contributing to field distortions are the misalignment of the trap [12], the truncation of electrodes [12], and the space charge [13,14]. As the existence of high order terms in electric field, the stability boundary deviates from the ideal value and the equation of motion for the ions will be nonlinear Mathieu equation.Most papers [15][16][17][18][19] deal with the time-dependent nonlinear terms with the method of pseudopotential well approximation [20].Using this approximation, high order terms become time-independent, and the nonlinear Mathieu equation is a normal nonlinear equation known as Duffing equation. The solution of such kind of equations has been well-studied [21]. When q u Ͻ 0.4 [2,22], this approximation accords well with the physical truth, some useful...
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