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Chen S, Kwok Y, Chen G. Time-Dependent Density Functional Theory for Open Systems and Its Applications. Acc Chem Res 2018; 51:385-393. [PMID: 29350516 DOI: 10.1021/acs.accounts.7b00382] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Photovoltaic devices, electrochemical cells, catalysis processes, light emitting diodes, scanning tunneling microscopes, molecular electronics, and related devices have one thing in common: open quantum systems where energy and matter are not conserved. Traditionally quantum chemistry is confined to isolated and closed systems, while quantum dissipation theory studies open quantum systems. The key quantity in quantum dissipation theory is the reduced system density matrix. As the reduced system density matrix is an O(M! × M!) matrix, where M is the number of the particles of the system of interest, quantum dissipation theory can only be employed to simulate systems of a few particles or degrees of freedom. It is thus important to combine quantum chemistry and quantum dissipation theory so that realistic open quantum systems can be simulated from first-principles. We have developed a first-principles method to simulate the dynamics of open electronic systems, the time-dependent density functional theory for open systems (TDDFT-OS). Instead of the reduced system density matrix, the key quantity is the reduced single-electron density matrix, which is an N × N matrix where N is the number of the atomic bases of the system of interest. As the dimension of the key quantity is drastically reduced, the TDDFT-OS can thus be used to simulate the dynamics of realistic open electronic systems and efficient numerical algorithms have been developed. As an application, we apply the method to study how quantum interference develops in a molecular transistor in time domain. We include electron-phonon interaction in our simulation and show that quantum interference in the given system is robust against nuclear vibration not only in the steady state but also in the transient dynamics. As another application, by combining TDDFT-OS with Ehrenfest dynamics, we study current-induced dissociation of water molecules under scanning tunneling microscopy and follow its time dependent dynamics. Given the rapid development in ultrafast experiments with atomic resolution in recent years, time dependent simulation of open electronic systems will be useful to gain insight and understanding of such experiments. This Account will mainly focus on the practical aspects of the TDDFT-OS method, describing the numerical implementation and demonstrating the method with applications.
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Zhou JW, Zou XM, Song SH, Chen GH. Quantum Dots Applied to Methodology on Detection of Pesticide and Veterinary Drug Residues. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:1307-1319. [PMID: 29378133 DOI: 10.1021/acs.jafc.7b05119] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The pesticide and veterinary drug residues brought by large-scale agricultural production have become one of the issues in the fields of food safety and environmental ecological security. It is necessary to develop the rapid, sensitive, qualitative and quantitative methodology for the detection of pesticide and veterinary drug residues. As one of the achievements of nanoscience, quantum dots (QDs) have been widely used in the detection of pesticide and veterinary drug residues. In these methodology studies, the used QD-signal styles include fluorescence, chemiluminescence, electrochemical luminescence, photoelectrochemistry, etc. QDs can also be assembled into sensors with different materials, such as QD-enzyme, QD-antibody, QD-aptamer, and QD-molecularly imprinted polymer sensors, etc. Plenty of study achievements in the field of detection of pesticide and veterinary drug residues have been obtained from the different combinations among these signals and sensors. They are summarized in this paper to provide a reference for the QD application in the detection of pesticide and veterinary drug residues.
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Chen S, Zhou W, Zhang Q, Kwok Y, Chen G, Ratner MA. Can Molecular Quantum Interference Effect Transistors Survive Vibration? J Phys Chem Lett 2017; 8:5166-5170. [PMID: 28974091 DOI: 10.1021/acs.jpclett.7b02214] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Quantum interference in cross-conjugated molecules can be utilized to construct molecular quantum interference effect transistors. However, whether its application can be achieved depends on the survivability of the quantum interference under real conditions such as nuclear vibration. We use two simulation methods to investigate the effects of nuclear vibration on quantum interference in a meta-linked benzene system. The simulation results suggest that the quantum interference is robust against nuclear vibration not only in the steady state but also in its transient dynamics, and thus the molecular quantum interference effect transistors can be realized.
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Liu Q, Wang J, Du P, Hu L, Zheng X, Chen G. Improving the Performance of Long-Range-Corrected Exchange-Correlation Functional with an Embedded Neural Network. J Phys Chem A 2017; 121:7273-7281. [DOI: 10.1021/acs.jpca.7b07045] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Li F, Raza A, Wang YW, Xu XQ, Chen GH. Optimization of Surfactant-Mediated, Ultrasonic-assisted Extraction of Antioxidant Polyphenols from Rattan Tea ( Ampelopsis grossedentata) Using Response Surface Methodology. Pharmacogn Mag 2017; 13:446-453. [PMID: 28839370 PMCID: PMC5551363 DOI: 10.4103/pm.pm_159_16] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Revised: 05/13/2016] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND Rattan tea is a medicinal plant that has been used for many years for the treatment of inflammation, fatty liver, tumor, diabetes, and hyperlipidemia. OBJECTIVE A green and novel approach based on surfactant-mediated, ultrasonic-assisted extraction (SM-UAE) was developed for the extraction of antioxidant polyphenols from Rattan tea. A nonionic surfactant Tween-80 was selected as extraction solvent. The antioxidant activity was measured by total phenolic content (TPC) and ferric-reducing/antioxidant capacity (FRAC) assay. MATERIALS AND METHODS Optimization of extraction parameters including concentration of solvent, ultrasonic time, and temperature were investigated by response surface methodology. The antioxidant activity was measured by TPC and FRAC assay. RESULTS The optimal extraction conditions were determined as 6.8% (v/v) of aqueous Tween-80, ultrasonic temperature of 54°C, and ultrasonic time of 28.8 min. Under these conditions, the highest TPC value of 360.4 mg gallic acid equivalent per gram of dry weight material (GAE/g DW) was recorded. Moreover, 6.8% (v/v) of aqueous Tween-80, ultrasonic temperature of 54.5°C, and ultrasonic time of 28.4 min were determined for the highest FRAC value of 478.2 μmol of Fe2+/g of weight material (μmol Fe2+/g DW). Compared with other methods, the TPC and FRAC values of 313.5 mg GAE/g DW and 389.6 μmol Fe2+/g DW were obtained by heat reflux extraction using ethanol as solvent, respectively, and 343.2 mg GAE/g DW and 450.1 μmol Fe2+/g DW were obtained by UAE using ethanol as solvent, respectively. CONCLUSION The application of SM-UAE markedly decreased extraction time or extraction cost and improved the extraction efficiency, compared with the other methods. SUMMARY Surfactant-mediated ultrasonic-assisted extraction of antioxidant polyphenols from Rattan TeaResponse surface methodology used to optimize parameters and study combined effectsOptimized surfactant-mediated ultrasonic-assisted extraction process enhances the antioxidant phenolics extraction in less time. Abbreviations used: SM-UAE: Surfactant-mediated ultrasonic-assisted extraction; TPC: total phenolic content; FRAC: Ferric reducing antioxidant capacity; RSM: Response surface methodology; BBD: Box-Behnken design.
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Guo X, Wang K, Chen GH, Shi J, Wu X, Di LL, Wang Y. Determination of strobilurin fungicide residues in fruits and vegetables by nonaqueous micellar electrokinetic capillary chromatography with indirect laser-induced fluorescence. Electrophoresis 2017; 38:2004-2010. [PMID: 28497571 DOI: 10.1002/elps.201700060] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 04/30/2017] [Accepted: 05/05/2017] [Indexed: 11/06/2022]
Abstract
A nonaqueous micellar electrokinetic capillary chromatography method with indirect LIF was developed for the determination of strobilurin fungicide residues in fruits and vegetables. Hydrophobic CdTe quantum dots (QDs) synthesized in aqueous phase were used as background fluorescent substance. The BGE solution, QD concentration, and separation voltage were optimized to obtain the best separation efficiency and the highest signal intensity. The optimal BGE solution consists of 40 mM phosphate, 120 mM sodium dodecyl sulfate, 15% v/v water and 15% v/v hydrophobic CdTe QDs in formamide, of which apparent pH is 9.5. The optimized separation voltage is controlled as 25 kV. The resultant detection limits of azoxystrobin, kresoxim-methyl, and pyraclostrobin are all 0.001 mg/kg, their linear dynamic ranges are 0.005-2.5 mg/kg, and the recoveries of the spiked samples are 81.7-96.1%, 86.5-95.7%, and 87.3-97.4%, respectively. This method has been proved to be sensitive enough to detect the aforementioned fungicides in fruits and vegetables at the maximum residue limits.
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Nie JC, Chen GH, Yan AQ, Liu XS. Placental site trophoblastic tumor in early stage: a case report. EUR J GYNAECOL ONCOL 2017; 38:479-481. [PMID: 29693898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Here, the authors present a case of a placental site trophoblastic tumor (PSTT) in a 28-year-old gravida 1 para 1 living 1 woman three months after vaginal delivery of a female infant at diagnosis in 2014. The patient was FIGO Stage I and finally underwent a total laparoscopic hysterectomy with ovarian conservation. Subsequently, the patient received two cycles of EMA/CO chemotherapy. Patient is on regular follow-up (clinical exam, β-hCG tests, pelvic and abdominal sonography) and has shown no signs of local or systemic recurrence for 24 months.
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Nie JC, Chen GH, Yan AQ, Liu XS. Postoperative chemotherapy on placental site trophoblastic tumor in early stage: analysis of 60 cases. EUR J GYNAECOL ONCOL 2017; 38:431-440. [PMID: 29693886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
PURPOSE OF INVESTIGATION To review the literature of placental site trophoblastic tumor (PSTT) and explore the effect of postoperative chemotherapy in patients with Stage I. MATERIALS AND METHODS The authors searched literature on Medline, Excerpta Medica Database (EMBASE), and other resources using the keywords "placental site trophoblastic tumor" and "PSTT" from 1981 ito 2014. RESULTS A total number of 60 patients with Stage I disease were identified, and the presentation, treatment, tumor response, disease status, and follow-up were retrieved and reviewed. According to the authors' knowledge, 725 cases associated with PSTT have been reported in 29 nations/areas since 1981. In this series, the probability of overall survival at ten years in the group of surgery alone and postoperative chemotherapy were 96.7% and 79.1% (p = 0.199), and recurrence-free survival rates were 91.8% and 63.3%, respectively. CONCLUSION The benefit from postoperative chemotherapy is still equivocal. There is a need for scrupulousness before adding postoperative chemotherapy.
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Wang R, Zhang Y, Bi F, Frauenheim T, Chen G, Yam C. Quantum mechanical modeling the emission pattern and polarization of nanoscale light emitting diodes. NANOSCALE 2016; 8:13168-13173. [PMID: 27249329 DOI: 10.1039/c6nr02356h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Understanding of the electroluminescence (EL) mechanism in optoelectronic devices is imperative for further optimization of their efficiency and effectiveness. Here, a quantum mechanical approach is formulated for modeling the EL processes in nanoscale light emitting diodes (LED). Based on non-equilibrium Green's function quantum transport equations, interactions with the electromagnetic vacuum environment are included to describe electrically driven light emission in the devices. The presented framework is illustrated by numerical simulations of a silicon nanowire LED device. EL spectra of the nanowire device under different bias voltages are obtained and, more importantly, the radiation pattern and polarization of optical emission can be determined using the current approach. This work is an important step forward towards atomistic quantum mechanical modeling of the electrically induced optical response in nanoscale systems.
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Guo XM, Liu XP, Chang GB, Xu L, Bi YL, Wang HZ, Zhang Y, Zhu PF, Wu Y, Chen GH. Characterization of the NLRC5 promoter in chicken: SNPs, regulatory elements and CpG islands. Anim Genet 2016; 47:579-87. [PMID: 27429394 DOI: 10.1111/age.12450] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/24/2016] [Indexed: 01/07/2023]
Abstract
NLRC5 plays an important role in the innate immunity and cellular immunity in many species, but the regulatory mechanism of NLRC5 expression in chickens remains unclear. In this study, a series of deletion fragments of the NLRC5 promoter region were constructed and dual-luciferase assay was performed. Then, we detected the SNP in the core region and its function. Important transcriptional regulatory elements were predicted and identified. Methylation of CpG islands was measured. The results revealed that the two core regions of -4372 to -3756 and -2925 to -2265 in the NLRC5 promoter were essential for NLRC5 mRNA expression in which a SNP (A/G), located at -2470, was found to have an effect on the transcriptional activity. Also, the STAT1 element in the second core region of the NLRC5 promoter was identified to bind with the STAT1 transcription factor, which was necessary for the transcriptional activity. In addition, many other elements in the NLRC5 promoter, including YY1 and CEBP, may contribute significantly to the expression activity of NLRC5. Moreover, two CpG islands were searched. Part of one was located in the first core region, which suggests that epigenetic modification may regulate the activity of the first promoter region, and the other was mostly in an unmethylated state. Collectively, these results suggest the complex regulation of NLRC5 expression includes SNPs, transcription factors and methylation.
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Shao YX, Chen GH, Fang R, Zhang L, Yi LX, Meng HL. Analysis of Six β-Lactam Residues in Milk and Egg by Micellar Electrokinetic Chromatography with Large-Volume Sample Stacking and Polarity Switching. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2016; 64:3456-3461. [PMID: 27088652 DOI: 10.1021/acs.jafc.6b00482] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A new micellar electrokinetic chromatography method with large-volume sample stacking and polarity switching was developed to analyze amoxicllin, cephalexin, oxacillin, penicillin G, cefazolin, and cefoperazone in milk and egg. The important parameters influencing separation and enrichment factors were optimized. The optimized running buffer consisted of 10 mM phosphate and 22 mM SDS at pH 6.7. The sample size was 1.47 kPa × 690 s, the reverse voltage was 20 kV, and the electric current recovery was 95%. Under these optimum conditions, the enrichment factors of six β-lactams were 193-601. Their LODs were <0.26 ng/g, and LOQs were all 2 ng/g, which was only 1/50-1/2 of the maximum residual limits demanded by U.S. and Japanese regulations. The intraday and interday RSDs of method were lower than 3.70 and 3.91%, respectively. The method can be applied to determine these six antibiotic residues in egg and milk.
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Gu B, Chen GH, Shen HJ, Ma X, Fu CC, Han Y, Tang XW, Miao M, Qiu HY, Sun AN, Wu DP. [Improved clinical outcome of acute myeloid leukemia with FLT3-ITD mutation treated with sorafenib]. ZHONGHUA NEI KE ZA ZHI 2016; 55:293-7. [PMID: 27030618 DOI: 10.3760/cma.j.issn.0578-1426.2016.04.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
OBJECTIVE To analyze the efficacy of sorafenib on the treatment of patients diagnosed as acute myeloid leukemia(AML) with FLT3-ITD mutation. METHODS From January 2012 to February 2015, 42 cases of AML with FLT3-ITD mutation according to MICM (morphology, immunology, cytogenetics and molecular) diagnosis system in our hospital were retrospectively analyzed. Thirty-two cases were refractory to chemotherapy or relapsed, who were treated with sorafenib or combined with chemotherapy. Ten patients relapsed after allogeneic hematopoietic stem cell transplantation (allo-HSCT), who were retreated with sorafenib or combined with donor lymphocyte infusion (DLI) or chemotherapy. In the first group, 13 of 32 patients accepted allo-HSCT. RESULTS The overall response rate of all 42 patients was 73.8%, including 4 (9.5%) complete molecular remission (CMR), 9 (21.4%) complete remission (CR), 8 (19%) complete remission with incomplete hematologic recovery (CRi), 10 (23.8%) partial remission (PR), and 11 (26.2%) none remission (NR). The response rate of sorafenib alone for 17 patients was 70.6%, and that of sorafenib plus chemotherapy was 66.7% (P=0.555). Thirteen patients who received allo-HSCT included 6 CMR/CR/CRi, 4 PR, and 3 NR before transplant. The 2-year overall survival (OS) rate and progress free survival (PFS) rate in all patients were 36.9% and 28.7%, and the corresponding median time were 18 months and 9 months respectively. The 2-year OS rate in 23 patients who received sorafenib combined with allo-HSCT was superior to that in 19 patients not receiving allo-HSCT (45.5% vs 23.9%, P=0.041), so was PFS rate (44.0% vs 9.7%, P=0.014). Twelve cases died of disease progression, four of infection, and one of chronic graft versus host disease after transplant. CONCLUSIONS Sorafenib combined with chemotherapy improves response rate of AML patients with FLT3-ITD mutation. Those who are treated with sorafenib plus allo-HSCT obtain better long-term survival.
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Chen GH, Ge YJ. [The clinical management of co-occurring insomnia and obstructive sleep apnea hypopnea syndrome]. LIN CHUANG ER BI YAN HOU TOU JING WAI KE ZA ZHI = JOURNAL OF CLINICAL OTORHINOLARYNGOLOGY, HEAD, AND NECK SURGERY 2016; 30:446-448. [PMID: 29871035 DOI: 10.13201/j.issn.1001-1781.2016.06.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Indexed: 06/08/2023]
Abstract
Insomnia and OSAHS are the comorbid diseases among the most common sleep disorders with high incidence. They both interact with each other apart from combined symptoms, therefore are defined as co-occurring insomnia and obstructive sleep apnea(CIO). CIO causes more serious damage to patients than single insomnia or OSAHS does, resulting in complex clinical treatments. However, the traditional treatment of CIO aims at solely OSAHS or insomnia patients with poor efficacy and compliance. Therefore, further investigation is required to elucidate the clinical mechanism and to optimize concurrent treatment for OSAHS and insomnia.
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Wang J, Cao H, Hong X, Chen GH, Fan HM, Li QC, Liu ZM, Li KF. MicroRNA screening and functional study of obliterative bronchiolitis in a rat model simulating lung transplantation. GENETICS AND MOLECULAR RESEARCH 2015; 14:19309-16. [PMID: 26782583 DOI: 10.4238/2015.december.29.40] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
The aim of this study was to provide the experimental basis for effective prevention and treatment of obliterative bronchiolitis (OB) by studying the changes on the microRNA (miRNA) expression profile after an orthotopic tracheal transplantation (OTT) simulating lung transplantation (LT). The OTT was performed on inbred rats to establish an OB animal model simulating LT, which was confirmed successful through pathological examination after 4 weeks. A miRNA microarray was used to screen for the most significantly differentially expressed miRNA in the OB tissues of donor transplanted trachea and real-time quantitative PCR was then used to validate the reliability of the microarray results. The microarray detection obtained 29 OB-related miRNAs, composed of 15 and 14 significantly up- and down-regulated miRNAs, respectively, among which miR-146a, miR-155, and miR-451, whose function is involved in the immune and inflammatory reactions, were subjected to relative quantitation research. The LT-simulated OTT-induced OB showed significantly differential expressions of multiple miRNAs, among which miR-146a and miR-155 were highly expressed, while miR-451 was lowly expressed, suggesting that these miRNAs may play an important regulatory role in the OB pathological process after LT.
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Han JC, Ma K, Wang JG, Chen GH, Zhang JL, Qu HX, Yan YF, Cheng YH. Effects of Non-phytate Phosphorus and 1a-Hydroxycholecalciferol on Growth Performance, Bone Mineralization, and Carcass Traits of Broiler Chickens. BRAZILIAN JOURNAL OF POULTRY SCIENCE 2015. [DOI: 10.1590/1516-635x1704503-510] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Wang HZ, Ma T, Chang GB, Wan F, Liu XP, Lu L, Xu L, Chen J, Chen GH. Single nucleotide polymorphism screening, molecular characterization, and evolutionary aspects of chicken Piwi genes. GENETICS AND MOLECULAR RESEARCH 2015; 14:14802-10. [PMID: 26600541 DOI: 10.4238/2015.november.18.45] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The P-element-induced wimpy testis (Piwi) gene is involved in germline stem cell self-renewal, meiosis, RNA silencing, and transcriptional regulation. Piwi genes are relatively well conserved in many species, but their function in poultry species is unclear. In this study, Piwi genes were sequenced using a target-sequence capture assay in quail and 28 breeds of chicken. Single nucleotide polymorphisms (SNPs) and evolutionary aspects of these chicken breeds were then analyzed. We found that SNP sites existed mainly in the introns of a few chicken breeds, and we selected an SNP on intron 4 for further verification by Sanger sequencing, the results of which were similar to those obtained by the target-capture sequencing assay. The evolutionary analysis revealed that there were more mutations in the Chahua and Leghorn breeds than in the other breeds, and that the phylogenetic tree was divided into four main categories that suggested that Piwi is evolutionarily conserved, and mutations in the introns might be associated with gametogenesis. The screened SNPs can be used as candidate markers for Piwi, and our results provide basic information for the further study of Piwi function in poultry.
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Meng L, Yam C, Zhang Y, Wang R, Chen G. Multiscale Modeling of Plasmon-Enhanced Power Conversion Efficiency in Nanostructured Solar Cells. J Phys Chem Lett 2015; 6:4410-4416. [PMID: 26722976 DOI: 10.1021/acs.jpclett.5b01913] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The unique optical properties of nanometallic structures can be exploited to confine light at subwavelength scales. This excellent light trapping is critical to improve light absorption efficiency in nanoscale photovoltaic devices. Here, we apply a multiscale quantum mechanics/electromagnetics (QM/EM) method to model the current-voltage characteristics and optical properties of plasmonic nanowire-based solar cells. The QM/EM method features a combination of first-principles quantum mechanical treatment of the photoactive component and classical description of electromagnetic environment. The coupled optical-electrical QM/EM simulations demonstrate a dramatic enhancement for power conversion efficiency of nanowire solar cells due to the surface plasmon effect of nanometallic structures. The improvement is attributed to the enhanced scattering of light into the photoactive layer. We further investigate the optimal configuration of the nanostructured solar cell. Our QM/EM simulation result demonstrates that a further increase of internal quantum efficiency can be achieved by scattering light into the n-doped region of the device.
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Han JC, Chen GH, Wang JG, Zhang JL, Qu HX, Zhang CM, Yan YF, Cheng YH. Evaluation of Relative Bioavailability of 25-Hydroxycholecalciferol to Cholecalciferol for Broiler Chickens. ASIAN-AUSTRALASIAN JOURNAL OF ANIMAL SCIENCES 2015; 29:1145-51. [PMID: 26954155 PMCID: PMC4932568 DOI: 10.5713/ajas.15.0553] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 08/25/2015] [Accepted: 10/14/2015] [Indexed: 11/27/2022]
Abstract
This study was conducted to evaluate the relative bioavailability (RBV) of 25-hydroxycholecalciferol (25-OH-D3) to cholecalciferol (vitamin D3) in 1- to 21-d-old broiler chickens fed with calcium (Ca)- and phosphorus (P)-deficient diets. On the day of hatch, 450 female Ross 308 broiler chickens were assigned to nine treatments, with five replicates of ten birds each. The basal diet contained 0.50% Ca and 0.25% non-phytate phosphorus (NPP) and was not supplemented with vitamin D. Vitamin D3 was fed at 0, 2.5, 5.0, 10.0, and 20.0 μg/kg, and 25-OH-D3 was fed at 1.25, 2.5, 5.0, and 10.0 μg/kg. The RBV of 25-OH-D3 was determined using vitamin D3 as the standard source by the slope ratio method. Vitamin D3 and 25-OH-D3 intake was used as the independent variable for regression analysis. The linear relationships between the level of vitamin D3 or 25-OH-D3 and body weight gain (BWG) and the weight, length, ash weight, and the percentage of ash, Ca, and P in femur, tibia, and metatarsus of broiler chickens were observed. Using BWG as the criterion, the RBV value of 25-OH-D3 to vitamin D3 was 1.85. Using the mineralization of the femur, tibia, and metatarsus as criteria, the RBV of 25-OH-D3 to vitamin D3 ranged from 1.82 to 2.45, 1.86 to 2.52, and 1.65 to 2.05, respectively. These data indicate that 25-OH-D3 is approximately 2.03 times as active as vitamin D3 in promoting growth performance and bone mineralization in broiler chicken diets.
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Zhang Y, Yam C, Chen G. A variational approach for dissipative quantum transport in a wide parameter space. J Chem Phys 2015; 143:104112. [PMID: 26619516 DOI: 10.1063/1.4930847] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Recent development of theoretical method for dissipative quantum transport has achieved notable progresses in the weak or strong electron-phonon coupling regime. However, a generalized theory for dissipative quantum transport in a wide parameter space had not been established. In this work, a variational polaron theory for dissipative quantum transport in a wide range of electron-phonon coupling is developed. The optimal polaron transformation is determined by the optimization of the Feynman-Bogoliubov upper bound of free energy. The free energy minimization ends up with an optimal mean-field Hamiltonian and a minimal interaction Hamiltonian. Hence, second-order perturbation can be applied to the transformed system, resulting in an accurate and efficient method for the treatment of dissipative quantum transport with different electron-phonon coupling strength. Numerical benchmark calculation on a single site model coupled to one phonon mode is presented.
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Han JC, Qu HX, Wang JG, Chen GH, Yan YF, Zhang JL, Hu FM, You LY, Cheng YH. Comparison of the Growth and Mineralization of the Femur, Tibia, and Metatarsus of Broiler Chicks. BRAZILIAN JOURNAL OF POULTRY SCIENCE 2015. [DOI: 10.1590/1516-635x1703333-340] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Zhang Y, Yam C, Chen G. Dissipative time-dependent quantum transport theory: Quantum interference and phonon induced decoherence dynamics. J Chem Phys 2015; 142:164101. [DOI: 10.1063/1.4918771] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Wang R, Zheng X, Kwok Y, Xie H, Chen G, Yam C. Time-dependent density functional theory for open systems with a positivity-preserving decomposition scheme for environment spectral functions. J Chem Phys 2015; 142:144112. [PMID: 25877567 DOI: 10.1063/1.4917172] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Understanding electronic dynamics on material surfaces is fundamentally important for applications including nanoelectronics, inhomogeneous catalysis, and photovoltaics. Practical approaches based on time-dependent density functional theory for open systems have been developed to characterize the dissipative dynamics of electrons in bulk materials. The accuracy and reliability of such approaches depend critically on how the electronic structure and memory effects of surrounding material environment are accounted for. In this work, we develop a novel squared-Lorentzian decomposition scheme, which preserves the positive semi-definiteness of the environment spectral matrix. The resulting electronic dynamics is guaranteed to be both accurate and convergent even in the long-time limit. The long-time stability of electronic dynamics simulation is thus greatly improved within the current decomposition scheme. The validity and usefulness of our new approach are exemplified via two prototypical model systems: quasi-one-dimensional atomic chains and two-dimensional bilayer graphene.
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van den Brand TPH, Roest K, Chen GH, Brdjanovic D, van Loosdrecht MCM. Occurrence and activity of sulphate reducing bacteria in aerobic activated sludge systems. World J Microbiol Biotechnol 2015; 31:507-16. [PMID: 25649202 DOI: 10.1007/s11274-015-1807-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 01/19/2015] [Indexed: 11/26/2022]
Abstract
In the sewage or wastewater treatment plant, biological sulphate reduction can occur spontaneously or be applied beneficially for its treatment. The results of this study can be applied to control SRB in the sewage and WWTP. Therefore, population diversity analyses of SRB for nine activated sludge wastewater treatment plants (WWTP) in the Netherlands and the effect of long-term (months) oxygen exposures on the SRB activity were carried out. T-RFLP and clone sequencing analyses of winter and summer samples revealed that (1) all WWTP have a similar SRB population, (2) there is no seasonal impact (10-20 °C) on the SRB population present in the WWTP and (3) Desulfobacter postgatei, Desulfovibrio desulfuricans and Desulfovibrio intestinalis were the most common and dominant SRB species observed in these samples, and origin from the sewage. Short term activity tests demonstrated that SRB were not active in the aerobic WWTP, but while flushed with N2-gas SRB became slightly active after 3 h. In a laboratory reactor at a dissolved oxygen concentration of <2 %, sulphate reduction occurred and 89 % COD removal was achieved. SRB grew in granules, in order to protect themselves for oxygen exposures. SRB are naturally present in aerobic WWTP, which is due to the formation of granules.
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Shi BX, Chen GH, Zhang ZJ, Hao JJ, Jing L, Zhou HY, Zhao J. First Report of Race Composition and Distribution of Sunflower Broomrape, Orobanche cumana, in China. PLANT DISEASE 2015; 99:291. [PMID: 30699572 DOI: 10.1094/pdis-07-14-0721-pdn] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Sunflower broomrape (Orobanche cumana Wallr.) is a holoparasitic plant that penetrates the vascular system of sunflower roots, absorbs plant nutrients and water, and thus causes stunting, reduced growth, and severe yield losses (3). To date, seven races of sunflower broomrape (O. cumana) have been identified by using international standard race differential hosts in Bulgaria, Serbia, Romania, Turkey, and Russia (4). However, the race types present in China are unknown. To identify the race composition of sunflower broomrape in China, race differential hosts of sunflower broomrape were received from Dr. Dragan Skoric (Serbian Academy of Sciences and Arts, Novi Sad, Serbia): Line AD66 has no resistant genes; Kruglik-41 contains resistant gene Or1; B-RO-02A has Or2; Record has Or3; LC1002B has Or4; LC1003B has Or5; LC-1093 has Or6, and Race-G-2 has Or7 (1). Eighteen sunflower broomrape samples were collected in August of 2011, 2012, and 2013 from different provinces/locations in China, including Xinjiang (Xinyuan, Shihezi, Tekesi, Beitun, Urumqi, and Yining), Inner Mongolia (Linhe, Xixiaozhao, Wuqianqi, Tuzuoqi, Keyouqianqi, and Aohanqi), Shanxi (Hunyuan, Shilou, Mizhi, and Dingbian), Jilin (Tongyu), and Hebei (Xuanhua). The differential hosts were each inoculated with the seeds of each broomrape isolate that was recovered, as described by Pancenko with minor modification (2). Briefly, two parts of field soil and one part of vermiculite were mixed together and used as potting mix. The mix was inoculated with broomrape seeds at 10 mg of seeds per 100 g of potting mix. The inoculated mix was placed in a 7-cm (diameter) × 11-cm (height) plastic pot to fill two-thirds of the pot volume. Three sunflower seeds were placed on the surface of the mix at an even distance from each other and covered with additional mix. The pots were kept in a greenhouse under a 16-h photoperiod at 10,000 lux of illumination intensity, temperature of 20-25°C, and 40% relative humidity. Forty days after incubation, sunflower seedlings were taken out from the pot and the roots washed with tap water. The number of tubercles was recorded on the root of each differential host. Race types were determined based on the reaction (tubercule formation on roots) of all the standard differential hosts to the test isolate. The results showed that races A, D, E, and G of O. cumana were present among the isolates. Race G was found in Wuqianqi, Xixiaozhao, and Linhe in the western part of Inner Mongolia. Race E was found only in Shihezi of Xinjiang. Race D was found in Aohanqi and Keyouqianqi (eastern part of Inner Mongolia); Xinyuan, Tekesi, Beitun, and Urumqi (northern part of Xinjiang); and Tongyu (northern part of Jilin). Race A was found in Mizhi, Shilou, and Hunyuan of Shanxi province and Xuanhua in Hebei province. Additionally, race A was also found in Tuzuoqi, the middle region of Inner Mongolia. Thus, races A, D, E, and G were the main race types of O. cumana in China. Race D was the predominant race type and had the widest distribution. Race G was the highest level race type in this study but was mainly limited to the western part of Inner Mongolia. This is the first report of race composition and distribution of sunflower broomrape (O. cumana) in China. References: (1) Y. Kaya et al. Helia 40:211, 2004. (2) A. N. Pancenko, Zbirnik VNIIMK. Page 107, 1973. (3) C. Parker. Page 17 in: Proc. 3rd Int. Workshop on Orobanche and Related Striga Research, 1994. (4) P. Shindrova et al. Helia 35:87, 2012.
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Yam C, Meng L, Zhang Y, Chen G. A multiscale quantum mechanics/electromagnetics method for device simulations. Chem Soc Rev 2015; 44:1763-76. [DOI: 10.1039/c4cs00348a] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This review highlights a newly developed multiscale method, incorporating quantum mechanics into device modeling with an environment included through classical electrodynamics.
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