This paper proposes a switched capacitor-based soft-switching proportional dimming LED driver to address color-mixing LED applications. The driver utilizes a half-bridge switch structure and ...incorporates a switched capacitor to regulate the dual resonant network. This configuration facilitates current sharing across each resonant network and enables fixed proportion dimming between them. The common inductance leveraged in this design results in fewer switching devices, thereby enhancing efficiency. Furthermore, all switches and diodes achieve soft switching, contributing to high efficiency. Finally, this paper built a 19 W experimental prototype, and the maximum efficiency reached 95.56%, which verified the correctness and feasibility of the driver.
One of the main challenges in industrial wastewater treatment and recovery is the removal of sulfate, which usually coexists with Ca2+ and Mg2+. The effect of Mg2+ on sulfate removal by ettringite ...precipitation was investigated, and the process was optimized in the absence and presence of Mg2+. In the absence of Mg2+, the optimum conditions with sulfate removal of 99.7% were obtained at calcium-to-sulfate ratio of 3.20, aluminum-to-sulfate ratio of 1.25 and pH of 11.3 using response surface methodology. In the presence of Mg2+, sulfate removal efficiency decreased with increasing Mg2+ concentration, and the inhibitory effect of Mg2+ matched the competitive inhibition Monod model with half maximum inhibition concentration of 57.4 mmol/L. X-ray diffraction and Fourier transform infrared spectroscopy analyses of precipitates revealed that ettringite was converted to hydrotalcite-type (HT) compound in the presence of Mg2+. The morphology of precipitates was transformed from prismatic crystals to stacked layered crystals, which confirmed that Mg2+ competes with Ca2+ for Al3+ to form HT compound. A two-stage process was designed with Mg2+ removal before ettringite precipitation to eliminate the inhibitory effect, and is potential to realize sludge recovery at the same time of effective removal of sulfate and hardness.
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•Sulfate removal by ettringite precipitation was optimized in the absence of Mg2+.•Mg2+ competes with Ca2+ for Al3+ and inhibits sulfate removal as ettringite.•Ettringite was converted to hydrotalcite-type compound in the presence of Mg2+.•A two-stage process was designed to eliminate Mg2+ inhibition and recover sludge.
Summary
Maize exhibits marked growth and yield response to supplemental nitrogen (N). Here, we report the functional characterization of a maize NIN‐like protein ZmNLP5 as a central hub in a ...molecular network associated with N metabolism. Predominantly expressed and accumulated in roots and vascular tissues, ZmNLP5 was shown to rapidly respond to nitrate treatment. Under limited N supply, compared with that of wild‐type (WT) seedlings, the zmnlp5 mutant seedlings accumulated less nitrate and nitrite in the root tissues and ammonium in the shoot tissues. The zmnlp5 mutant plants accumulated less nitrogen than the WT plants in the ear leaves and seed kernels. Furthermore, the mutants carrying the transgenic ZmNLP5 cDNA fragment significantly increased the nitrate content in the root tissues compared with that of the zmnlp5 mutants. In the zmnlp5 mutant plants, loss of the ZmNLP5 function led to changes in expression for a significant number of genes involved in N signalling and metabolism. We further show that ZmNLP5 directly regulates the expression of nitrite reductase 1.1 (ZmNIR1.1) by binding to the nitrate‐responsive cis‐element at the 5′ UTR of the gene. Interestingly, a natural loss‐of‐function allele of ZmNLP5 in Mo17 conferred less N accumulation in the ear leaves and seed kernels resembling that of the zmnlp5 mutant plants. Our findings show that ZmNLP5 is involved in mediating the plant response to N in maize.
Significance Statement
In this study, we report the functional characterization of ZmNLP5 for its role in modulating the N response, suggesting that ZmNLP5 is a potential candidate for improving N use efficiency in maize production.
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•The maximum adsorption capacity of E2 onto GO was 149.4mg/g at 298K and pH 7.0.•The adsorption process was characterized by kinetics, isotherm and thermodynamic analysis.•The E2 ...adsorption onto GO worked well in the presence of NaCl.•GO still remained excellent adsorption capacity after numerous desorption/adsorption cycles.•The adsorption mechanism was believed to be π–π interactions and hydrogen bonds between GO and E2.
This study demonstrates the use of few-layered graphene oxide nanosheets (GO) as efficient adsorbents for the removal of 17β-Estradiol (E2) from aqueous solutions via strong adsorptive interactions. The adsorption performance of GO was investigated by batch adsorption experiments. Further, adsorption experiments were carried out in the presence of other environmental pollutants to understand external influence on the adsorption of E2 by GO. The result indicated that the maximum adsorption capacity (qm) of GO for E2 obtained from the Langmuir isotherm was 149.4mg/g at 298K and it was the highest values of E2 adsorption compared to that of other adsorbents reported before. Thermodynamic study indicated that the adsorption was a spontaneous process. In addition, the result showed that E2 adsorption on GO was slight affected by the solution pH. The presence of NaCl in the solution facilitated the E2 adsorption and the optimum adsorption capacity was obtained when the NaCl concentration was 0.001M. Moreover, the effect of background electrolyte divalent cations (Mg2+ and Ca2+) was not similar with the monovalent cations (Na+ and K+). While the influence of background electrolyte anions (Cl−, NO3-, SO42-, and PO43-) were not significantly different. The presence of humic acid reduced E2 adsorption on GO at pH 7.0. GO still exhibited excellent adsorption capacity following numerous desorption/adsorption cycles. Besides, both π–π interactions and hydrogen bonds might be responsible for the adsorption of E2 onto GO.
The occurrence of emerging contaminants in our water resources poses potential threats to the livings. Due to the poor treatment in wastewater management, treatment technologies are needed to ...effectively remove these products for living organism safety. In this study, Graphene oxide (GO) was tested for the first time for its capacity to remove a kind of emerging wastewater contaminants, metformin. The research was conducted by using a series of systematic adsorption and kinetic experiments. The results indicated that GO could rapidly and efficiently reduce the concentration of metformin, which could provide a solution in handling this problem. The uptake of metformin on the graphene oxide was strongly dependent on temperature, pH, ionic strength, and background electrolyte. The adsorption kinetic experiments revealed that almost 80% removal of metformin was achieved within 20 min for all the doses studied, corresponding to the relatively high k1 (0.232 min−1) and k2 (0.007 g mg−1 min−1) values in the kinetic models. It indicated that the highest adsorption capacity in the investigated range (qm) of GO for metformin was at pH 6.0 and 288 K. Thermodynamic study indicated that the adsorption was a spontaneous (ΔG0 < 0) and exothermic (ΔH0 < 0) process. The adsorption of metformin increased when the pH values changed from 4.0 to 6.0, and decreased adsorption were observed at pH 6.0–11.0. GO still exhibited excellent adsorption capacity after several desorption/adsorption cycles. Besides, both so-called π–π interactions and hydrogen bonds might be mainly responsible for the adsorption of metformin onto GO.
•Rapid and efficient removal of metformin can be achieved during the adsorption process.•Sorption kinetic, isothermal and thermodynamic characteristics of metformin are explored.•The adsorption capacity of GO for metformin is influenced in the presence of NaCl and background electrolyte.•The adsorption mechanism is believed to be so-called π–π interactions and hydrogen bonds between GO and metformin.
The derivation of human embryonic stem (hES) cells currently requires the destruction of ex utero embryos. A previous study in mice indicates that it might be possible to generate embryonic stem (ES) ...cells using a single-cell biopsy similar to that used in preimplantation genetic diagnosis (PGD), which does not interfere with the embryo's developmental potential. By growing the single blastomere overnight, the resulting cells could be used for both genetic testing and stem cell derivation without affecting the clinical outcome of the procedure. Here we report a series of ten separate experiments demonstrating that hES cells can be derived from single blastomeres. In this proof-of-principle study, multiple biopsies were taken from each embryo using micromanipulation techniques and none of the biopsied embryos were allowed to develop in culture. Nineteen ES-cell-like outgrowths and two stable hES cell lines were obtained. The latter hES cell lines maintained undifferentiated proliferation for more than eight months, and showed normal karyotype and expression of markers of pluripotency, including Oct-4, SSEA-3, SSEA-4, TRA-1-60, TRA-1-81, nanog and alkaline phosphatase. These cells retained the potential to form derivatives of all three embryonic germ layers both in vitro and in teratomas. The ability to create new stem cell lines and therapies without destroying embryos would address the ethical concerns of many, and allow the generation of matched tissue for children and siblings born from transferred PGD embryos.
Human induced pluripotent stem cells (hiPSC) have been shown to differentiate into a variety of replacement cell types. Detailed evaluation and comparison with their human embryonic stem cell (hESC) ...counterparts is critical for assessment of their therapeutic potential. Using established methods, we demonstrate here that hiPSCs are capable of generating hemangioblasts/blast cells (BCs), endothelial cells, and hematopoietic cells with phenotypic and morphologic characteristics similar to those derived from hESCs, but with a dramatic decreased efficiency. Furthermore, in distinct contrast with the hESC derivatives, functional differences were observed in BCs derived from hiPSCs, including significantly increased apoptosis, severely limited growth and expansion capability, and a substantially decreased hematopoietic colony-forming capability. After further differentiation into erythroid cells, >1,000-fold difference in expansion capability was observed in hiPSC-BCs versus hESC-BCs. Although endothelial cells derived from hiPSCs were capable of taking up acetylated low-density lipoprotein and forming capillary-vascular-like structures on Matrigel, these cells also demonstrated early cellular senescence (most of the endothelial cells senesced after one passage). Similarly, retinal pigmented epithelium cells derived from hiPSCs began senescing in the first passage. Before clinical application, it will be necessary to determine the cause and extent of such abnormalities and whether they also occur in hiPSCs generated using different reprogramming methods.
In the past year, video blogs (vlogs) seem to have become a major form of information acquisition and entertainment socializing for the Internet users. The vlog, which is essentially a digital diary, ...is an emerging video content form and is touted by multimedia as the next mainstay of the video blogging era. Many creators have achieved self-branding and self-promotion through the continuous output of vlogs. Vlog visibility has greatly increased and has become a new territory for promotion. Therefore, analyzing the impact of vlog promotional content on consumer attitudes is important to provide companies with a theoretical basis for developing vlog promotions. Based on a large amount of literature and book research, this study proposes three attitude components in reference to the ABC attitude model: cognitive attitude, affective attitude, and behavioral tendency. Based on this, a questionnaire was designed to determine the influence of vlog promotion on consumer attitudes, and correlation and regression analyses were conducted on the three outcome and six predictor variables according to the results. All six predictors were determined to have different degrees of influence on consumer attitudes, with the vlogger’s (who provides the vlog) understanding of the advertised products having the most influence on cognitive attitudes. This was also the most influential factors in affective attitudes and behavioral tendency; the second-most influential factors for these are the degree of fan interactivity with the vlogger and vlog content, respectively.
In this paper, a thiacalix4arene complex Zn2(TIT4A)L2·4DMF·2CH3OH (H2L = 4,4′-oxybisbenzoic acid) (Zn-TIT4A-L) was synthesized by a solvothermal method. The composites were prepared by combining ...Zn-TIT4A-L with reduced graphene oxide (RGO), mesoporous carbon (MC), and multi-walled carbon nanotubes (MWCNTs), respectively. Three representative composites are Zn-TIT4A-L@RGO(1:1), Zn-TIT4A-L@MC(1:2), and Zn-TIT4A-L@MWCNT(1:2). X-ray diffraction and scanning electron microscopy characterized their structures and morphologies. The results showed that three composites were successfully prepared, and the crystals of the complex remained in the composites. The electrochemical properties of the composites were characterized by electrochemical impedance spectroscopy and cyclic voltammetry. The results indicated that they had good electrocatalytic activity and conductivity. Among them, Zn-TIT4A-L@RGO(1:1) had the best performance and was used for the quantitative detection of flutamide (FTA). The linear range of detection is 0.1–200 μM, and the limit of detection is 0.015 μM. At the same time, the sensor also had good reproducibility, anti-interference, and stability. The sensor was also used for the detection of FTA in lake water, human urine, and serum with a satisfactory recovery rate. The possible mechanism of electrochemical detection of FTA was also discussed.
The process performance of a full-scale sludge process reduction activated sludge (SPRAS) system in long-term operation were investigated by inserting a micro-aerobic tank and a clarifier before ...conventional activated sludge process. The full-scale SPRAS for industrial park wastewater treatment achieved efficient pollutants removal and a low observed sludge yield of 0.074 g SS/g COD. Batch tests showed that influent feeding into the micro-aerobic tank favored sludge reduction, and obtained a sludge decay constant of 0.168 d−1. The SPRAS enriched slow growers and hydrolytic bacteria for sludge reduction, showed high simultaneous nitrification and denitrification efficiency in the micro-aerobic tank with abundant denitrifying bacteria, and improved sludge settleability by enriching floc-forming bacteria. Process configuration of the SPRAS was beneficial to enhance maintenance metabolism, cyclic micro-aerobic and anaerobic uncoupling, and lysis-cryptic growth for sludge reduction. Techno-economic analysis showed that the SPRAS greatly reduced sludge production with small footprint and low cost.
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