Publications by authors named "Zhaokun Wang"

25 Publications

  • Page 1 of 1

Generation of coherent multicolor noise-like pulse complex in Yb-doped fiber laser mode-locked by GIMF-SA.

Opt Express 2021 May;29(10):14336-14344

We have demonstrated the generation of multicolor noise-like pulse complex in a passively Yb-doped mode-locked fiber laser based on a single mode-graded index multimode-single mode fiber (SMF-GIMF-SMF) device as the saturable absorber (SA). The stimulated Raman scattering (SRS) effect leads to the cascaded generation of the main noise-like pulse (NLP) at 1028.8 nm together with the noise like Raman pulse (RP) at 1076.1 nm. The generated dual wavelength pulses demonstrate the unique properties of mutually synchronization and coherence. The autocorrelation traces show that each of the synchronously mode-locked pulses exhibits a double-scale structure with a narrow peak which consists of a train of quasi-periodic beat pulses with a 35.7 fs pulse width and a pulse separation of about 77.2 fs. The total output power reaches 102.5 mW with 34% of it belonging to the RP. And furthermore, by separating the two pulses with spectral filters, the modulation fringes cannot be observed anymore. These results indicate that the Raman component participates in the mode-locking operation as a 'signal' instead of 'noise'. Such a coherent Raman pulse source provides a novel platform for numerous applications, such as frequency comb spectroscopy and so on.
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http://dx.doi.org/10.1364/OE.425326DOI Listing
May 2021

High-power synchronous multi-wavelength solitons from a multimode mode-locked fiber laser system.

Opt Lett 2021 Jan;46(1):118-121

In this Letter, we implement a multimode fiber (MMF) laser system mode-locked by a nonlinear polarization rotation technique for controllable synchronous multi-wavelength soliton generation. The synchronization of the repetition rates for different wavelengths is realized by the special mode transmission in MMF. For dual-wavelength mode-locking at 1566.7 nm and 1617.2 nm, each of the synchronously mode-locked solitons consists of a train of quasi-periodic beat pulses with a pulse width of 84 fs and period of 162 fs. The total output power reaches 532 mW with optimally balanced two-color intensities. Furthermore, switchable dual- and tri-wavelength synchronized femtosecond pulses are also obtained. In contrast to previous reports, this synchronously mode-locked multi-wavelength is output directly from a laser oscillator, which provides a simpler candidate to achieve pulse synchronization.
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http://dx.doi.org/10.1364/OL.412739DOI Listing
January 2021

Integrative Analysis Extracts a Core ceRNA Network of the Fetal Hippocampus With Down Syndrome.

Front Genet 2020 30;11:565955. Epub 2020 Nov 30.

Medical Genetic Institute of Henan Province, Henan Provincial Key Laboratory of Genetic Diseases and Functional Genomics, National Health Commission Key Laboratory of Birth Defects Prevention, People's Hospital of Zhengzhou University, Zhengzhou, China.

Accumulating evidence suggests that circular RNAs (circRNAs)-miRNA-mRNA ceRNA regulatory network-may play an important role in neurological disorders, such as Alzheimer's disease (AD). Interestingly, neuropathological changes that closely resemble AD have been found in nearly all Down syndrome (DS) cases > 35 years. However, few studies have reported circRNA transcriptional profiling in DS cases, which is caused by a chromosomal aberration of trisomy 21. Here, we characterized the expression profiles of circRNAs in the fetal hippocampus of DS patients ( = 8) and controls ( = 6) by using microarray. MiRNA, mRNA expression profiling of DS from our previous study and scRNA-seq data describing normal fetal hippocampus development (GEO) were also integrated into the analysis. The similarity between circRNAs/genes with traits/cell-types was calculated by weighted correlation network analysis (WGCNA). miRanda and miRWalk2 were used to predict ceRNA network interactions. We identified a total of 7,078 significantly differentially expressed (DE) circRNAs, including 2,637 upregulated and 4,441 downregulated genes, respectively. WGCNA obtained 15 hub circRNAs and 6 modules with cell type-specific expression patterns among scRNA-seq data. Finally, a core ceRNA network was constructed by 14 hub circRNAs, 17 DE miRNA targets and 245 DE mRNA targets with a cell type-specific expression pattern annotation. Known functional molecules in DS or neurodegeneration (e.g., miR-138, OLIG1, and TPM2) were also included in this network. Our findings are the first to delineate the landscape of circRNAs in DS and the first to effectively integrate ceRNA regulation with scRNA-seq data. These data may provide a valuable resource for further research on the molecular mechanisms or therapeutic targets underlying DS neuropathy.
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http://dx.doi.org/10.3389/fgene.2020.565955DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7735064PMC
November 2020

Epigenetic modification-dependent androgen receptor occupancy facilitates the ectopic TSPY1 expression in prostate cancer cells.

Cancer Sci 2021 Feb 7;112(2):691-702. Epub 2020 Dec 7.

Department of Medical Genetics, State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu, China.

Testis-specific protein Y-encoded 1 (TSPY1), a Y chromosome-linked oncogene, is frequently activated in prostate cancers (PCa) and its expression is correlated with the poor prognosis of PCa. However, the cause of the ectopic transcription of TSPY1 in PCa remains unclear. Here, we observed that the methylation status in the CpG islands (CGI) of the TSPY1 promoter was negatively correlated with its expression level in different human samples. The acetyl-histone H4 and trimethylated histone H3-lysine 4, two post-translational modifications of histones occupying the TSPY1 promoter, facilitated the TSPY1 expression in PCa cells. In addition, we found that androgen accelerated the TSPY1 transcription on the condition of hypomethylated of TSPY1-CGI and promoted PCa cell proliferation. Moreover, the binding of androgen receptor (AR) to the TSPY1 promoter, enhancing TSPY1 transcription, was detected in PCa cells. Taken together, our findings identified the regulation of DNA methylation, acting as a primary mechanism, on TSPY1 expression in PCa, and revealed that TSPY1 is an androgen-AR axis-regulated oncogene, suggesting a novel and potential target for PCa therapy.
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http://dx.doi.org/10.1111/cas.14731DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7894013PMC
February 2021

Machine learning assisted dual-channel carbon quantum dots-based fluorescence sensor array for detection of tetracyclines.

Spectrochim Acta A Mol Biomol Spectrosc 2020 May 11;232:118147. Epub 2020 Feb 11.

College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, PR China. Electronic address:

The detection and differentiation of tetracyclines (TCs) has received increasing attention due to the severe threat they pose to human health and the ecological balance. A dual-channel fluorescence sensor array based on two carbon quantum dots (CDs) was fabricated to distinguish between four TCs, including tetracycline (TC), oxytetracycline (OTC), doxycycline (DOX), and metacycline (MTC). A distinct fluorescence variation pattern (I/I) was produced when CDs interacted with the four TCs. This pattern was analyzed by LDA and SVM. This was the first time that SVM was used for data processing of fluorescence sensor arrays. LDA and SVM showed that the array has the capacity for parallel and accurate determination of TCs at concentrations between 1.0 μM and 150 μM. In addition, the interference experiment using metal ions and antibiotics as possible coexisting interference substances proves that the sensor array has excellent selectivity and anti-interference ability. The array was also used for the accurate detection and identification of TCs in binary mixtures, and furthermore, the four TCs were successfully identified in river water and milk samples. Besides, the sensor array successfully identified the four TCs in 72 unknown samples with a 100% accuracy. The results proved that SVM can achieve the same accurate classification and prediction as LDA, and considering its additional advantages, it can be used as an optional supplementary method for data processing, thereby expanding the data processing field.
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http://dx.doi.org/10.1016/j.saa.2020.118147DOI Listing
May 2020

Modelling floppy iris syndrome and the impact of pupil size and ring devices on iris displacement.

Eye (Lond) 2020 12 4;34(12):2227-2234. Epub 2020 Feb 4.

School of Mathematics and Statistics, University of Glasgow, Glasgow, UK.

Introduction: The aim of this paper was to further develop a previously described finite element model which equates clinical iris billowing movements with mechanical buckling behaviour, simulating floppy iris syndrome. We wished to evaluate the impact of pupil dilation and mechanical devices on normal iris and floppy iris models.

Methods: Theoretical mathematical modelling and computer simulations were used to assess billowing/buckling patterns of the iris under loading pressures for the undilated and dilated normal iris, the undilated and dilated floppy iris, and additionally with a mechanical ring device.

Results: For the normal iris, billowing/buckling occurred at a critical pressure of 19.92 mmHg for 5 mm pupil size, which increased to 28.00 mmHg (40.56%) with a 7 mm pupil. The Malyugin ring device significantly increased critical initiating buckling pressures in the normal iris scenario, to 34.58 mmHg (73.59%) for 7 mm ring with boundary conditions I (BC I) and 34.51 mmHg (73.24%) with BC II. For the most floppy iris modelling (40% degradation), initiating buckling value was 18.04 mmHg (-9.44%), which increased to 28.39 mmHg (42.52%) with the 7 mm ring. These results were much greater than for normal undilated iris without restrictive mechanical expansion (19.92 mmHg).

Conclusion: This simulation demonstrates that pupil expansion devices inhibit iris billowing even in the setting of floppy iris syndrome. Our work also provides a model to further investigate the impact of pupil size or pharmacological interventions on anterior segment conditions affected by iris position.
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http://dx.doi.org/10.1038/s41433-020-0782-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7784872PMC
December 2020

[Analysis of MYO7A gene mutation in a family with non-syndromic autosomal recessive deafness].

Zhonghua Yi Xue Yi Chuan Xue Za Zhi 2019 Oct;36(10):965-969

People's Hospital of Zhengzhou University, Zhengzhou, Henan 450000, China.

Objective: To explore the genetic basis for a family with non-syndromic autosomal recessive deafness.

Methods: The proband and her parents were subjected to physical and audiological examinations. With genomic DNA extracted from peripheral blood samples, next-generation sequencing was carried out using a panel for deafness genes. Suspected mutation was validated by Sanger sequencing and qPCR analysis of her parents.

Results: The proband presented bilateral severe sensorineural hearing loss at three days after birth. Her auditory threshold was 110-120 dBnHL but with absence of vestibular and retinal symptoms. Her brother also had deafness but her parents were normal. No abnormality was found upon physical examination of her family members, while audiological examination showed no middle ear or retrocochlear diseases. Next-generation sequencing identified compound heterozygous mutations of the MYO7A gene, including a previously known c.462C>A (p. Cys154Ter) and a novel EX43_46 Del, which were respectively derived from her mother and father.

Conclusion: The compound heterozygous mutations of the MYO7A gene probably underlie the disease in this family. Our findings has enriched the mutation spectrum for non-syndromic autosomal recessive deafness 2.
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http://dx.doi.org/10.3760/cma.j.issn.1003-9406.2019.10.004DOI Listing
October 2019

Enantioselective degradation of chiral fungicides triticonazole and prothioconazole in soils and their enantioselective accumulation in earthworms Eisenia fetida.

Ecotoxicol Environ Saf 2019 Nov 1;183:109491. Epub 2019 Aug 1.

School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, Liaoning, 110016, PR China. Electronic address:

Triticonazole and prothioconazole are widely used systemic agricultural triazole fungicides both with a chiral center. In this work, the enantioselective degradation of triticonazole and prothioconazole in three types of soils were investigated under native conditions using reversed phase liquid chromatography-tandem mass spectrometry with a Chiralcel OD-RH column. The results indicated that the enantioselective degradation was observed with S-triticonazole and R-prothioconazole preferentially degraded and the degradation rate was fast with a half-life within 6 days. It was also found that the presence of earthworms can accelerate the degradation and further enhance degradation enantioselectivity of triticonazole and prothioconazole in soils. Moreover, the enantioselective of triticonazole and prothioconazole in earthworms were studied. The results showed that the bioaccumulation was enantioselective with R-triticonazole and S-prothioconazole preferentially accumulated, which was similar to the soil. Our findings suggest that the enantioselective toxicity and potential effects of the metabolites should be considered for more accurate assessment of ecological risks of triticonazole and prothioconazole to target and non-target species.
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http://dx.doi.org/10.1016/j.ecoenv.2019.109491DOI Listing
November 2019

Classification for plastic bottles recycling based on image recognition.

Waste Manag 2019 Apr 25;88:170-181. Epub 2019 Mar 25.

School of Mechanical Engineering, Nanjing University of Science and Technology, 210094 Nanjing, China.

Recycling of used plastic bottles is an important measure to protect the environment and save energy. Usually, bottles in different colors have different value for recycling. Classification of plastic bottles recycling based on image recognition during recycling is an effective way, where the position and color recognition are the key technologies. To classify the plastic bottles on the conveyor belt, their position relationships are firstly defined as three categories, i.e. disjoint, adjacent and overlapping. The disjoint ones can be easily identified by the ratio of concave and convex area based on their image. For the adjacent and overlapping bottles, a combination method called distance transformation and threshold segmentation is proposed to distinguish their position relationships. Once the adjacent bottles are identified, the method of concave point search based on convex hull will be used to separate the adjacent recycled bottles further. Then, the color of both the disjoint and adjacent bottles is identified because it is too complex and difficult to recognize color of and separate the overlapping bottles. In the aspect of color recognition, the colors of recycled bottles are divided into seven categories in the sorting process. Color features of the bottom section are used to represent the one of the recycled bottle because there may be a bottle cap and a label on the top and in the middle of the bottle, respectively, resulting in the wrong recognition. ReliefF algorithm is applied to select color features of recycled bottles and the color is identified by support vector machine (SVM) algorithm. The influence of training sample size on classification model is studied and the experimental results show that the accuracy of color recognition of recycled bottles reach 94.7%.
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http://dx.doi.org/10.1016/j.wasman.2019.03.032DOI Listing
April 2019

Novel compound heterozygous mutations of the DOCK6 gene in a familial case of Adams-Oliver syndrome 2.

Gene 2019 Jun 19;700:65-69. Epub 2019 Mar 19.

Medical Genetics Institute of Henan Province, Henan Provincial Key Laboratory of Genetic Diseases and Functional Genomics, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China. Electronic address:

Introduction: Adams-Oliver syndrome (AOS) is a rare developmental disorder characterized by the combination of aplasia cutis congenita of the scalp vertex and terminal transverse limb defects. DOCK6 (Dedicator of cytokinesis 6) is one of the six identified AOS genes.

Methods: We performed targeted next-generation sequencing (NGS) of a child with an AOS phenotype. Sanger DNA sequencing further validated her lineal consanguinity. To explore the pathological features of the mutation, a minigene assay was used to investigate the effects of the mutation on splicing.

Results: Two compound heterozygous DOCK6 mutations (c.4106+2T>C and c.3063 C>G (p.Y1021*)) were identified in this family, and both mutations have not been reported previously. Sanger DNA sequencing indicated that the mutations were inherited maternally and paternally, respectively. The results of the minigene assay showed that the c.4106+2T>C mutation resulted in aberrant splicing and caused a four-nucleotide insertion in the transcript and a premature stop codon.

Conclusions: Our findings expanded the number of reported cases of this rare disease and the mutation spectrum of DOCK6 mutations, which can serve as the basis for prenatal diagnosis and genetic counseling.
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http://dx.doi.org/10.1016/j.gene.2019.03.023DOI Listing
June 2019

Magnetic solid-phase extraction based on carbon [email protected] O for enantioselective determination of eight triazole fungicides in water samples.

Electrophoresis 2019 05 12;40(9):1306-1313. Epub 2019 Feb 12.

Lab of Analytical Chemistry, School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, Liaoning Province, P. R. China.

In this work, a carbon nanosphere decorated by Fe O nanoparticles was prepared, characterized and used as the magnetic adsorbent. Eight commonly used chiral triazole fungicides, including penconazole, uniconazole, paclobutrazol, triazolone, tebuconazole, hexaconazole, triticonazole and epoxiconazole were extracted from two environmental water samples (river water and lake water) by magnetic solid-phase extraction, followed by the enantiomeric analysis on a Chiralpark IC column coupled with a triple quadrupole mass spectrometry to evaluate their possible stereoselective degradation occurring in the water samples. The possible factors affecting the extraction performance, such as amount of used adsorbents, pH and ionic strength of water solution, types and volumes of desorption solvents were systematically investigated. Under the optimum conditions, extraction yields of eight triazole fungicides were above 80% and the concentration factors were as high as 1000. Method detection and quantification limits for the enantiomers of eight triazole fungicides were in the range of 0.56-6.95 ng/L. Satisfactory accuracy (relative recovery 77.8-93.5%), good intraday precision (RSD 4.3-9.8%) and interday precision (RSD 3.1-7.9%) were also obtained. The developed method provided the simplicity of operation, rapidity and high enrichment factor, which can be used to monitor and evaluate the behavior of the individual enantiomer of chiral triazole fungicides.
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http://dx.doi.org/10.1002/elps.201800530DOI Listing
May 2019

Generation of pulse-width controllable dissipative solitons and bound solitons by using an all fiber saturable absorber.

Opt Lett 2019 Feb;44(3):570-573

A passively mode-locked fiber laser with controllable pulse width is demonstrated by use of an all-fiber saturable absorber based on a hybrid no-core fiber (NCF)-graded index multimode fiber (GIMF) structure incorporated into an Er-doped fiber ring cavity. Such a hybrid NCF-GIMF structure has a tunable intracavity filtering effect. As a result, the mode-locking operation is achieved with controllable pulse width and spectral bandwidth in the normal dispersion regime by only stretching the fiber device. Soliton pulses with the pulse width of 7.7-23 ps are generated, and bound solitons with variable widths are also experimentally demonstrated. The results obtained reveal the versatility and flexibility of the NCF-GIMF structured device in controlling the pulse dynamics for different experimental requirements.
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http://dx.doi.org/10.1364/OL.44.000570DOI Listing
February 2019

Simultaneous enantioselective determination of 22 chiral pesticides in fruits and vegetables using chiral liquid chromatography coupled with tandem mass spectrometry.

Food Chem 2019 Mar 27;277:298-306. Epub 2018 Oct 27.

School of Pharmacy, Shenyang Pharmaceutical University, 103 Wenhua Road Shenhe District, 110016 Shenyang, Liaoning Province, PR China. Electronic address:

This paper presents a novel multi-residue method for the enantioselective analysis of 22 chiral pesticides in cucumber, tomato, cabbage, grape, mulberry, apple and pear at enantiomeric levels. Pesticides were efficiently extracted by magnetic solid-phase extraction based on graphene as sorbent. Response surface methodology was used to assist the multivariable optimization. The perfect chiral separation of the enantiomers was achieved on a Chiralpak IG column within 47 min by reversed-phase liquid chromatography coupled with tandem mass spectrometry, which is a significant improvement to resolve a large group of chiral compounds under one set of conditions. The method was validated in terms of selectivity, linearity, sensitivity, trueness and precision, which all satisfy the requirement for pesticides residue analysis. The proposed method was successfully applied for monitoring the occurrence and enantiomeric composition of pesticides in different fruits and vegetables, demonstrating its applicability for the routine analysis of chiral pesticide residues in food samples.
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http://dx.doi.org/10.1016/j.foodchem.2018.10.128DOI Listing
March 2019

Generalized Hartmann-Shack array of dielectric metalens sub-arrays for polarimetric beam profiling.

Nat Commun 2018 11 2;9(1):4607. Epub 2018 Nov 2.

Institute of Nanotechnology and Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), 76021, Karlsruhe, Germany.

To define and characterize optical systems, obtaining the amplitude, phase, and polarization profile of optical beams is of utmost importance. Traditional polarimetry is well established to characterize the polarization state. Recently, metasurfaces have successfully been introduced as compact optical components. Here, we take the metasurface concept to the system level by realizing arrays of metalenses, allowing the determination of the polarization profile of an optical beam. We use silicon-based metalenses with a numerical aperture of 0.32 and a mean measured focusing efficiency in transmission mode of 28% at a wavelength of 1550 nm. Our system is extremely compact and allows for real-time beam diagnostics by inspecting the foci amplitudes. By further analyzing the foci displacements in the spirit of a Hartmann-Shack wavefront sensor, we can simultaneously detect phase-gradient profiles. As application examples, we diagnose the profiles of a radially polarized beam, an azimuthally polarized beam, and of a vortex beam.
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http://dx.doi.org/10.1038/s41467-018-07056-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6214988PMC
November 2018

Multi-residue enantiomeric analysis of 18 chiral pesticides in water, soil and river sediment using magnetic solid-phase extraction based on amino modified multiwalled carbon nanotubes and chiral liquid chromatography coupled with tandem mass spectrometry.

J Chromatogr A 2018 Sep 6;1568:8-21. Epub 2018 Jul 6.

School of Pharmacy, Shenyang Pharmaceutical University, 103 Wenhua Road Shenhe District, 110016, Shenyang, Liaoning Province, PR China. Electronic address:

This manuscript describes, for the first time, the multi-residue analysis of 18 chiral pesticides at enantiomeric levels in both environmental liquid (river water, influent and effluent wastewater) and solid matrices (agricultural soil, forestal soil and river sediment) based on magnetic solid-phase extraction (MSPE) and chiral liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Magnetic amino modified multiwalled carbon nanotubes (m-MWCNTs-NH) were prepared and firstly applied to adsorb pesticides from complex matrices. Response surface methodology (RSM) was applied to assist the multivariable optimization. The simultaneous enantioseparation of the chiral pesticides was performed on a Chiralpak IG column. Under the optimum conditions, the mean recoveries for pesticides enantiomers from the water matrices ranged from 81.1 to 106.3% with intra-day RSD of 2.1-11.9% and inter-day RSD of 2.6-12.7%; the mean recoveries for all enantiomers from the solid matrices ranged from 80.3 to 105.9% with intra-day RSD of 2.3-10.9% and inter-day RSD of 4.0-13.4%. Good linearity was achieved for all enantiomers with determination coefficients (r) greater than 0.9912. Method quantification limits were below 2.04ng L in liquid matrices and below 0.50ng g in solid matrices. The developed method offered some advantages, such as simple operation, rapidity and high concentration factor. Therefore, it is suitable for monitoring the enantiomeric compositions of chiral pesticides in different environmental matrices.
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http://dx.doi.org/10.1016/j.chroma.2018.07.022DOI Listing
September 2018

Visualized nutrition education and dietary behavioral change: A systematic review and meta-analysis.

Crit Rev Food Sci Nutr 2019 22;59(12):1976-1985. Epub 2018 Dec 22.

a School of Public Health, Peking University Health Science Center , Beijing , China.

Effectiveness of using visual approaches in health education and its influential factors were still in debate. This study aimed to asess the effects of visualized nutrition education on dietary knowledge and behavioral changes, and factors influencing them. A comprehensive search of PubMed, EMBASE, Scopus, and Cochrane Library was conducted. Eligible studies were trials assessed effects of visualized nutrition education on dietary knowledge or behavior changes, compared with non-visualized or no education group. Fourteen studies ( = 7,259) were qualitatively analyzed and 7 of them were included in the meta-analysis. We found a higher fiber intake in both short term (1.59 g/1000 kcals, 95% CI 0.90-2.27) and long term (1.36 g/1000 kcals, 95% CI 0.64-2.09). A marginal advantage was shown in short-term fruits and vegetables consumption (F&V consumption) (standardized mean difference [SMD] = 0.08, 95% CI -0.00 to 0.16). The education effects were more pronounced when education was delivered in series (SMD = 0.09, 95% CI 0.00-0.17), avoiding loss-framing (SMD = 0.31, 95% CI 0.10-0.51) and video modeling (SMD = 0.23, 95% CI 0.03-0.43), with short length plus cultural adaptation. Visualized nutrition education was overall promising in improving dietary behaviors. Delivering in series, short in length, with cultural adaptation were features tended to enlarge the benefits of visualized education while loss-framing and video modeling might be avoided.
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http://dx.doi.org/10.1080/10408398.2018.1469466DOI Listing
December 2019

Stretched graded-index multimode optical fiber as a saturable absorber for erbium-doped fiber laser mode locking.

Opt Lett 2018 May;43(9):2078-2081

A novel mode-locking method based on the nonlinear multimode interference in the stretched graded-index multimode optical fiber (GIMF) is proposed in this Letter. The simple device geometry, where the light is coupled in and out of the stretched GIMF via single-mode fibers, is demonstrated to exhibit the temporal intensity discrimination required for mode locking. The nonlinear saturable absorber (SA) characteristics of the device are controllable by simply adjusting the strength of the stretching applied. The modulation depth of the device, which consists of ∼23.5  cm GIMF, is tuned from 10.37% to 22.27%. Such a simple SA enables the wavelength-switchable mode-locking operation in a ring Er-doped fiber laser, and ultrafast pulses with a pulse width of 506 fs at 1572.5 nm and 416 fs at 1591.4 nm were generated. The versatility and simplicity of the SA device, together with the possibility of scaling the pulse energy, make it highly attractive in ultrafast photonics.
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http://dx.doi.org/10.1364/OL.43.002078DOI Listing
May 2018

Magnetic solid-phase extraction based on FeO/graphene nanocomposites for enantioselective determination of representative profens in the environmental water samples and molecular docking study on adsorption mechanism of graphene.

J Pharm Biomed Anal 2018 Jul 18;156:88-96. Epub 2018 Apr 18.

School of Pharmacy, Shenyang Pharmaceutical University, 103 Wenhua Road Shenhe District, 110016, Shenyang, Liaoning Province, PR China. Electronic address:

In this work, a nanocomposite, FeO/graphene was prepared and characterized. Five profens (including ibuprofen, flurbiprofen, pranoprofen, indoprofen and loxoprofen sodium) were extracted from three environmental water samples by using the synthetic FeO/graphene, followed by simultaneous determination of the enantiomers on a Chiralcel OJ-RH column coupled with a triple quadrupole mass spectrometry. Factors affecting the extraction efficiency, such as amount of adsorbents, solution pH, ionic strength, type and volume of desorption solvent, as well as elution time were thoroughly investigated. Method validation showed high sensitivity with method quantification limits in the range of 8.49-26.3 ng/L. Satisfactory recovery (73.6-90.2%), good intra-day precision (RSD 3.2-9.7%) and inter-day precision (RSD 5.2-10%) were also obtained. Furthermore, possible interactions between analyte and graphene, such as electrostatic attraction, charge-π interaction, hydrophobic interaction and π-π stacking were discussed by combining the experiment results and molecular docking study, which provided a new insight into the adsorption mechanism of graphene.
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http://dx.doi.org/10.1016/j.jpba.2018.04.023DOI Listing
July 2018

Saturable absorber based on a single mode fiber - graded index fiber - single mode fiber structure with inner micro-cavity.

Opt Express 2018 Jan;26(2):927-934

An Er-doped mode-locked fiber laser with a saturable absorber based on single mode - graded index multimode - single mode fiber (SMF-GIMF-SMF) with inner micro-cavity is demonstrated. The modulation depth of the saturable absorber was measured to be 1.9% when the SMF-GIMF-SMF structure is bent to a certain state. Such a simple saturable absorber enables the mode-locking operation in a ring Er-doped fiber laser and ultrafast pulses with pulse energy of 0.026 nJ and pulse width of 528 fs at the fundamental repetition rate of 14.34 MHz can be generated. In addition, the harmonic mode-locking operation can also be achieved.
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http://dx.doi.org/10.1364/OE.26.000927DOI Listing
January 2018

Magnetic solid-phase extraction based on magnetic multiwalled carbon nanotubes for the simultaneous enantiomeric analysis of five β-blockers in the environmental samples by chiral liquid chromatography coupled with tandem mass spectrometry.

Talanta 2018 Apr 14;180:98-107. Epub 2017 Dec 14.

School of Pharmacy, Shenyang Pharmaceutical University, 103 Wenhua Road Shenhe District, 110016 Shenyang, Liaoning Province, PR China. Electronic address:

In this work, the magnetic multiwalled carbon nanotubes (Mag-MWCNTs) were prepared by self-assembly method and characterized by scanning electron microscopy, X-ray powder diffraction, energy dispersive X-ray and vibrating sample magnetometer. Then, these synthetic Mag-MWCNTs were used as sorbents to extract five β-blockers (atenolol, metoprolol, esmolol, pindolol and arotinolol) by magnetic solid-phase extraction. The target analytes adsorbed on Mag-MWCNTs were eluted and determined on a chiral α-acid glycoprotein column coupled with a triple quadrupole mass spectrometry. Eventually, the proposed method was applied to the analysis of the enantiomeric composition of the studied β-blockers in three environmental samples, including river water, influent wastewater and effluent wastewater. Method detection and quantification limits for all enantiomers were in the range of 0.50-1.45 and 1.63-3.75ng/L, respectively. Satisfactory recovery (82.9-95.6%), good intra-day precision (RSD 0.4-10.4%) and inter-day precision (RSD 2.9-7.4%) were also obtained. With numerous advantages such as simplicity of operation, rapidity and high enrichment factor, the newly developed method has potential to assess the enantioselectivity of chiral drugs in ecotoxicity and biodegradation processes, which is also a new expanded application of Mag-MWCNTs in the environmental analysis.
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http://dx.doi.org/10.1016/j.talanta.2017.12.034DOI Listing
April 2018

Mode-locked Tm fiber laser using SMF-SIMF-GIMF-SMF fiber structure as a saturable absorber.

Opt Express 2017 Oct;25(22):26546-26553

We demonstrate a mode-locked all-fiber Tm laser using a single mode-step index multimode-graded-index multimode-single mode fiber structure as a saturable absorber based on the nonlinear multimodal interference. Stable fundamentally mode-locking operation was obtained at a pump threshold of 180mW. The output soliton pulses had a center wavelength, spectral width, pulse duration, and repetition rate of 1888 nm, 3.6 nm, 1.4 ps, and19.82 MHz, respectively. This is a simple, low-cost, stable, and convenient laser oscillator with many potential applications in eye-safe ultrafast photonics.
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http://dx.doi.org/10.1364/OE.25.026546DOI Listing
October 2017

Comparison of three S-β-CDs with different degrees of substitution for the chiral separation of 12 drugs in capillary electrophoresis.

Chirality 2017 Sep 11;29(9):558-565. Epub 2017 Jul 11.

Department of Pharmaceutical Analysis, School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, Liaoning Province, P.R. China.

Three kinds of sulfated β-cyclodextrin (S-β-CD), including a single isomer, heptakis-6-sulfato-β-cyclodextrin (HS-β-CD), degree of substitution (DS) of 7, which was synthesized in our laboratory and another two commercialized randomly substituted mixtures, a sulfated β-cyclodextrin with DS of 7 to 11, as well as a highly sulfated-β-cyclodextrin with DS of 12 to 15, were used for the enantioresolution of 12 drugs (the β-blockers, phenethylamines, and anticholinergic agents) in capillary electrophoresis. The enantioseparation under varying concentrations of S-β-CD and background electrolyte pH were systematically investigated and compared. Based on the experimental results, the effect of the nature of S-β-CD and analyte structure on the enantioseparation is discussed.
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http://dx.doi.org/10.1002/chir.22731DOI Listing
September 2017

Manipulation of wavefront using helical metamaterials.

Opt Express 2016 Aug;24(16):18266-76

Helical metamaterials, a kind of 3-dimensional structure, has relatively strong coupling effect among the helical nano-wires. Therefore, it is expected to be a good candidate for generating phase shift and controlling wavefront with high efficiency. In this paper, using the finite-difference time-domain (FDTD) method, we studied the phase shift properties in the helical metamaterials. It is found that the phase shift occurs for both transmitted and reflected light waves. And the maximum of reflection coefficients can reach over 60%. In addition, the phase shift (φ) is dispersionless in the range of 600 nm to 860 nm, that is, it is only dominated by the initial angle (θ) of the helix. The relationship between them is φ = ± 2θ. Using Jones calculus we give a further explanation for these properties. Finally, by arranging the helixes in an array with a constant phase gradient, the phenomenon of anomalous refraction was also observed in a broad wavelength range.
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http://dx.doi.org/10.1364/OE.24.018266DOI Listing
August 2016

Separation of folinic acid diastereomers in capillary electrophoresis using a new cationic β-cyclodextrin derivative.

PLoS One 2015 17;10(3):e0120216. Epub 2015 Mar 17.

Department of Pharmaceutical Analysis, School of Pharmacy, Shenyang Pharmaceutical University, Ministry of Education, Shenyang, Liaoning Province, P. R. China.

A method for the separation of folinic acid diastereomers by capillary electrophoresis in chiral separation media was developed. Aiming to achieve a good separation of the anionic analytes, a newly synthesized cationic β-cyclodextrin derivative, mono-6-deoxy-6-piperdine-β-cyclodextrin, was applied as the chiral selector. The effect of background electrolyte pH, the concentration of the cyclodextrin additive, and organic modifier on the separation was investigated. A good separation of folinic acid diastereomers was obtained with 30 mmol/L phosphate buffer at pH 6.50 containing 6.0 mmol/L of mono-6-deoxy-6-piperdine-β-cyclodextrin in 10% acetonitrile. Based on the capillary electrophoresis data, the binding constants of each diastereomer with mono-6-deoxy-6-piperdine-β-cyclodextrin were determined. Moreover, a computational modeling study, using the semi-empirical PM3 method, was used to discuss the possible mechanism of separation of folinic acid with mono-6-deoxy-6-piperdine-β-cyclodextrin.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0120216PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4364531PMC
February 2016

Linearly-polarized short-pulse AOM Q-switched 978 nm photonic crystal fiber laser.

Opt Express 2013 Dec;21(24):29249-54

A linearly-polarized, high peak power, short-pulse, Q-switching Yb-doped large-mode-area photonic crystal fiber (PCF) oscillator with three-level system operation is demonstrated. By optimizing cavity parameters and adopting linear polarization component, the laser can easily obtain linearly-polarized output over 2 W at 978 nm with polarization extinction ratio (PER) up to 43 dB without any additional wavelength filter. Less than 50 ns stable output pulses are achieved within repetition range of 10 kHz-200 kHz and short pulse of 9 ns pulse duration, 130 kW peak power at 10 kHz can be reached. The characteristics and the key issues of the laser, such as interpulse ASE, spectrum ASE around 1030 nm, are with detailed discussion in the paper.
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http://dx.doi.org/10.1364/OE.21.029249DOI Listing
December 2013