Hua Yang

Publications (92)177.21 Total impact

• Article: Pseudoexfoliation: Normative Data and Associations: The Beijing Eye Study 2011.

  Qi Sheng You, Liang Xu, Ya Xing Wang, Hua Yang, Ke Ma, Jian Jun Li, Li Zhang, Jost B Jonas
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  ABSTRACT: OBJECTIVE: To assess the prevalence of pseudoexfoliation syndrome (PEX) and its associations in a population-based setting. DESIGN: Population-based, cross-sectional cohort study. PARTICIPANTS: Of 4403 eligible subjects with an age of ≥50 years, 3468 individuals (78.8%) participated in the Beijing Eye Study 2011 (mean age, 64.6±9.8 years; range, 50-93 years). METHODS: All study participants underwent a detailed ophthalmologic examination. After medical pupil dilation, PEX was assessed by an experienced ophthalmologist using slit-lamp-based biomicroscopy. MAIN OUTCOME MEASURES: Prevalence and associations of PEX. RESULTS: Slit-lamp examination results were available for 3022 study participants (87.1%). Definite pseudoexfoliation was observed in 72 of the 3022 subjects, with a prevalence of 2.38% (95% confidence interval [CI], 1.84-2.93). Suspected PEX was detected in 104 of the subjects (3.44%; 95% CI, 2.8-4.1). The overall prevalence of PEX (definite and suspected) was 176 of 3022 or 5.82% (95% CI, 4.99-6.66). In 80 subjects (45.5%), PEX was detected in both eyes, whereas it was detected only in the right eye in 42 subjects (23.9%) and only in the left eye in 54 (30.7%). The prevalence of PEX increased from 1.1% in among those 50 to 54 years old, to 3.5%, 5.7%, and 11.8% among those 60 to 64 years, 70 to 74 years, and ≥80 years, respectively. In multivariate analysis, presence of PEX was significantly associated with older age (P<0.001; odds ratio [OR], 1.08; 95% CI, 1.04-1.10), shorter axial length (P = 0.03; OR, 0.82; 95% CI, 0.68,0.98), and shallower anterior chamber (P = 0.03; OR, 0.59; 95% CI, 0.36-0.95). We found that PEX was not associated (all P>0.05) with sex, diabetes mellitus, blood pressure, psychological depression, smoking, dyslipidemia, body mass index, central corneal thickness, corneal diameter, optic nerve head measurements, choroidal thickness, retinal vessel diameters, early age-related macular degeneration, or retinal vein occlusion. CONCLUSIONS: In a North Chinese population aged ≥50 years, the prevalence of definite PEX was 2.38% (95% CI, 1.84-2.93), suspect PEX was 3.4% (95% CI, 2.8-4.1) and overall PEX was 5.82% (95% CI, 4.99-6.66). We found PEX to be associated with older age, shorter axial length, and shallower anterior chamber. The relationship between PEX and glaucomatous optic neuropathy remained inconclusive among our population. FINANCIAL DISCLOSURE(S): The authors have no proprietary or commercial interest in any materials discussed in this article.
  Ophthalmology 04/2013; · 5.45 Impact Factor
• Article: Localized retinal nerve fiber layer defects and arterial hypertension.

  Liang Xu, Jin Qiong Zhou, Shuang Wang, Ya Xing Wang, Qi Sheng You, Hua Yang, Ya Qin Zhang, Ming Ying Wu, Ya Feng Lu, You Yu Fan, Jost B Jonas
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  ABSTRACT: BACKGROUND We examined the relationship between arterial hypertension, localized retinal nerve fiber layer defects (RNFLDs), and retinal vascular abnormalities. METHODS The study included 359 patients with arterial hypertension and 331 individuals without hypertension as control subjects. Localized RNFLDs and retinal vascular abnormalities were assessed on fundus photographs. RESULTS After adjusting for blood concentrations of glycosylated hemoglobin (HbA1c), high-density lipoproteins, low-density lipoproteins, and hyperlipidemia in a multivariable analysis, localized RNFLDs were, in addition to arterio-venous nicking and generalized arteriolar narrowing, significantly associated with arterial hypertension. After adjusting for body mass index, waist/hip ratio, blood concentrations of glucose, HbA1c, triglycerides, high-density lipoproteins, low-density lipoproteins, and prevalence of diabetes mellitus and hyperlipidemia, categories of arterial blood pressure (optimal/normal/highly normal; mild, moderate and severe hypertension) were significantly associated with localized RNFLDs, which were present significantly more often in hypertension grades 2 and 3, with odds ratios (ORs) of 10.01 and 6.45, respectively. The corresponding ORs for arterio-venous nicking (hypertension grades 1, 2, and 3: ORs of 2.00, 1.68, and 1.99, respectively) and generalized arteriolar narrowing (hypertension grades 1 and 3; ORs of 4.60 and 4.32, respectively) were lower than those for localized RNFLDs. CONCLUSIONS Localized RNFLDs, in addition to retinal microvascular abnormalities such as focal and generalized arteriolar narrowing, were associated with different grades of arterial hypertension. Ophthalmoscopic examination for localized RNFLDs may be useful for the assessment of the retinal abnormalities associated with arterial hypertension and for the grading of arterial hypertension.
  American Journal of Hypertension 04/2013; 26(4):511-7. · 3.18 Impact Factor
• Article: Prevalence of macular holes as cause for visual impairment. The Beijing Eye Public Healthcare Project.

  Liang Xu, Qi Sheng You, Ya Xing Wang, Qing Feng Liang, Tong Tong Cui, Xiao Hui Yang, Hua Yang, Jost B Jonas
  Acta ophthalmologica 03/2013; 91(2):e157-8. · 2.44 Impact Factor
• Article: Pupil size: The Beijing Eye Study.

  Ya Xing Wang, Liang Xu, Qi Sheng You, Hua Yang, Jost B Jonas
  Acta ophthalmologica 03/2013; 91(2):e158-9. · 2.44 Impact Factor
• Article: Magnetic properties of carbon-encapsulated Fe-Co alloy nanoparticles.

  Aibing Wu, Xuwei Yang, Hua Yang
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  ABSTRACT: Carbon-encapsulated Fe-Co alloy nanoparticles (Fe-Co(C)) have been fabricated with different Co/Fe ratios by an efficient solid-state route using melamine as carbon source. The structure and morphology of Fe-Co(C) nanoparticles were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The XRD characterization results reveal that all products are alloys with no carbide impurity. The TEM and HRTEM observations show that the alloy nanoparticles are encapsulated in carbon shells. Additionally, the reactions involved in the syntheses are postulated. The variation of magnetic properties of Fe-Co(C) with Co/Fe has been discussed according to the room temperature VSM measurement results.
  Dalton Transactions 02/2013; · 3.84 Impact Factor
• Article: Optic nerve head morphology in young patients after antiglaucomatous filtering surgery.

  Songhomitra Panda-Jonas, Liang Xu, Hua Yang, Ya X Wang, Shefali B Jonas, Jost B Jonas
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  ABSTRACT: Purpose: To compare the optic nerve head appearance in glaucomatous eyes before and after marked reduction of intraocular pressure (IOP). Methods: The hospital-based observational case-series study included selected glaucoma patients for whom optic disc photographs taken before and 1 week to 5 months after surgical reduction of IOP were morphometrically examined. Results: The study included 23 eyes of 16 patients (mean age: 28.7 ± 6.0 years). Mean preoperative IOP was 31.6 ± 7.7 mmHg (22-52 mmHg), and mean IOP drop was 21.5 ± 8.4 mmHg (11-45 mmHg). The horizontal disc diameter decreased significantly (p < 0.001) after surgery, while the vertical disc diameter did not change markedly (p = 0.54). The width of the neuroretinal rim increased significantly in all disc quadrants (all p-values ≤ 0.01), optic cup depth decreased (p < 0.001), and reflectivity of the inner retinal surface increased significantly (p < 0.001). Some eyes showed a pronounced reduction in beta zone of parapapillary atrophy parallel to an increase in horizontal disc diameter, and some eyes showed an enlargement of beta zone parallel to a reduction in horizontal disc diameter. Conclusions: After marked reduction of high IOP, some eyes of young adult patients with glaucoma can show a horizontal shrinkage of the optic nerve head, in addition to a partial restoration of the neuroretinal rim and a flattening of the optic cup. In addition, beta zone of parapapillary atrophy can decrease or increase, complementarily to changes in the horizontal disc diameter. These findings may be of interest for the biomechanics of the optic nerve head and the precision of imaging techniques.
  Acta ophthalmologica 01/2013; · 2.44 Impact Factor
• Article: 10-Year Incidence and Associations of Pterygium in Adult Chinese. The Beijing Eye Study.

  Liang Zhao, Qi Sheng You, Liang Xu, Ke Ma, Ya Xing Wang, Hua Yang, Jost B Jonas
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  ABSTRACT: PURPOSE: To assess the 10-year incidence of pterygium and associated factors in adult Chinese. Methods: The population-based, longitudinal Beijing Eye Study, which included 4439 subjects (age: 40+ years) in 2001, was repeated in 2011 with 2695 subjects participating (66.4% of the survivors). Eyes with a pterygium in 2001 (n=90) were additionally excluded. The study participants underwent a detailed ophthalmic examination including slit lamp examination for detection of pterygia and corneal photography for measurement of the pterygia. Results: Incident pterygia were detected in 157/5300 eyes (2.9±0.3%) of 129/2628 persons (4.9±0.4%). In 101 (78.3%) subjects, the incident pterygia had occurred unilaterally. Out of 44 participants with unilateral pterygium in 2001, 6 (13.6%) subjects developed an incident pterygium in the fellow eye during the 10-year follow up. In the age groups of 40-49 years, 50-59 years, 60-69 years, and 70+ years, the 10-year incidence of pterygia was 5.4±0.7%, 4.7±0.7%, 4.5±0.8% and 5.0±1.5%, respectively. The length of pterygium was 30.4±14.7% of the corneal diameter. In multivariate analysis, the 10-year incidence of pterygia was associated with rural region of habitation (P<0.001; Odds Ratio (OR): 0.24; 95% Confidence Interval (CI): 0.14, 0.42) and lower fasting blood concentration of glucose (P=0.009;OR:0.82;95%CI:0.71,0.95), while level of education (P=0.90), cognitive score (P=0.64), occupation as farmer versus non-farmer (P=0.47), diastolic blood pressure (P=0.11) and systolic blood pressure (P=0.10) were not significantly associated. CONCLUSIONS: The 10-year incidence of pterygium in adult Chinese was 4.9%. It was significantly associated with rural region of habitation and lower fasting blood glucose concentration.
  Investigative ophthalmology & visual science 01/2013; · 3.43 Impact Factor
• Article: Prevalence and associations of incomplete posterior vitreous detachment in adult chinese: the beijing eye study.

  Lei Shao, Liang Xu, Qi Sheng You, Ya Xing Wang, Chang Xi Chen, Hua Yang, Jin Qiong Zhou, Jost B Jonas, Wen Bin Wei
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  ABSTRACT: To determine prevalence and associations of incomplete posterior vitreous detachment (PVD). The population-based cross-sectional Beijing Eye Study 2011 included 3468 individuals with a mean age of 64.6±9.8 years (range: 50-93 years). A detailed ophthalmic examination was performed including spectral-domain optical coherence tomography (SD-OCT). Incomplete PVD was differentiated into type 1 (shallow PVD with circular perifoveal vitreous attachment), type 2 (PVD reaching fovea but not foveola), type 3 (shallow PVD with pinpoint vitreous attachment at the foveola), and type 4 (PVD completely detached from the macula, attached to the optic disc). An incomplete PVD was detected in 3948 eyes (prevalence: 60.5±0.6%; 95% Confidence Interval (CI): 59.3%,61.7%) of 2198 subjects (67.1±0.8%;95%CI: 65.6%,68.7%). Type 1 PVD was seen in 3090 (78.3%) eyes, type 2 PVD in 504 (12.8%) eyes, type 3 PVD in 70 (1.8%) eyes, and type 4 PVD in 284 (7.2%) eyes. Prevalence of incomplete PVD was associated with younger age (P<0.001;OR:0.91), male gender (P<0.001;OR:0.64), rural region of habitation (P<0.001;OR:0.49), larger corneal diameter (P = 0.04;OR:0.91), better best corrected visual acuity (P = 0.02;OR:0.41), and hyperopic refractive error (P<0.001;OR:1.15). The type of incomplete PVD was associated with higher age (P<0.001), urban region of habitation (P<0.001), myopic refractive error (P = 0.001), thinner cornea (P = 0.005), and better best corrected visual acuity (P = 0.056). In adult Chinese in Greater Beijing, prevalence of an incomplete PVD (detected in 67.1% subjects) was associated with younger age, male gender, rural region of habitation, larger corneal diameter, better best corrected visual acuity and hyperopic refractive error.
  PLoS ONE 01/2013; 8(3):e58498. · 4.09 Impact Factor
• Article: Ophthalmoscopic assessment of the retinal nerve fiber layer. The beijing eye study.

  Yaqin Zhang, Liang Xu, Li Zhang, Hua Yang, Ya Xing Wang, Jost B Jonas
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  ABSTRACT: To examine the retinal nerve fiber layer (RNFL) ophthalmoscopically, to search for localized RNFL defects, and to assess factors associated with RNFL visibility in a population-based setting. The population-based cross-sectional Beijing Eye Study 2006 included 3251 subjects. Using color fundus photographs, RNFL visibility was assessed in grades from 0 to 8 in 8 fundus sectors. Localized RNFL defects were defined as wedge-shaped defects running towards the optic disc. After exclusion of subjects with optic media opacities, 2602 subjects (mean age:58.1±9.0 years) were included. RNFL visibility score was highest (P<0.001) in the temporal inferior region, followed by the temporal superior region, nasal superior region, and nasal inferior region. In multivariate analysis, higher RNFL visibility score was associated with younger age (P<0.001;standardized coefficient beta:-0.44;regression coefficient B: -0.22; 95%CI: -0.24, -0.20), female gender (P<0.001;beta:0.11;B:1.00;95%CI:0.67,1.32), higher blood concentration of low-density lipoproteins (P = 0.002;beta:0.07;B:0.34;95%CI:0.13,0.56), absence of dyslipidemia (P = 0.001;beta: -0.07;B: -0.58;95%CI: -0.93, -0.24), lower blood glucose concentration (P = 0.006;beta: -0.05;B: -0.14;95%CI: -0.24, -0.04), hyperopic refractive error (P<0.001;beta:0.15;B:0.45;95%CI:0.34,0.56), smaller optic disc size (P<0.001;beta: -0.08; B:-0.72;95% CI:-1.04, -0.40), absence of glaucomatous optic neuropathy (P<0.001;beta: -0.06;B: -2.69;95%CI:-4.18, -1.21) and absence of non-glaucomatous optic nerve damage (P = 0.001;beta: -0.06;B: -4.80;95%CI:0. -7.64, -1.96). Localized RNFL defects were detected in 96 subjects (prevalence:3.7±0.45% (95% confidence interval(CI):3.0,4.4). In multivariate analysis, prevalence of localized RNFL defects was associated with higher blood pressure (P<0.001; odds ratio (OR):1.07;95%CI:1.03,1.10), higher concentration of low-density lipoproteins (P = 0.01;OR:1.42;95%CI:1.08,1.85), higher prevalence of glaucomatous optic neuropathy (P<0.001;OR:46.8;95%CI:19.4,113) and diabetic retinopathy (P = 0.002;OR:3.20;95%CI:1.53,6.67), and lower total RNFL visibility (P<0.001;OR:0.92;95%CI:0.88,0.96). In Chinese aged 45+ years, a decreased RNFL visibility was associated with older age, male gender, dyslipidemia, hyperglycemia, myopia, larger optic disc, and glaucomatous or non-glaucomatous optic neuropathy. Localized RNFL defects (prevalence:3.7±0.45%) were correlated mainly with higher blood pressure, higher concentration of low-density lipoproteins, glaucomatous optic neuropathy and diabetic retinopathy. These data are helpful for the routine ophthalmoscopic examination of the RNFL.
  PLoS ONE 01/2013; 8(4):e62022. · 4.09 Impact Factor
• Article: Prevalence of diabetic retinopathy as cause for visual impairment: the Beijing Public Health Care Project.

  Qi S You, Liang Xu, Ya X Wang, Qing F Liang, Tong T Cui, Xiao H Yang, Hua Yang, Jost B Jonas
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  ABSTRACT: Diabetic retinopathy is the leading cause of blindness among working-aged adults around the world(1) Despite its significance and the rising prevalence of diabetes in general,(2,3) only few estimates of the prevalence of diabetic retinopathy have been performed in large-scaled studies. We therefore examined the prevalence of diabetic retinopathy in a health care project. The Beijing Eye Public Health Care Project was a population-based study designed to screen all inhabitants aged 55-85 years and living in the rural regions of the Beijing Municipality.(4) The Ethics Committee of the Beijing Tongren Hospital approved the study and all participants gave informed consent. In the population of 3.5 million people, all houses were visited by 2,500 trained ophthalmic technicians who performed an interview and assessed habitual visual acuity. All subjects with a visual acuity of <0.30 in any eye were asked to visit the next primary health care center, where digitized photographs of the ocular anterior segment and fundus were taken (non-mydriatic fundus camera CR DGi, Canon Co. Tokyo, Japan). In the reading center of the Beijing Institute of Ophthalmology, the diagnosis of the major causes of visual impairment was made.
  Clinical and Experimental Ophthalmology 12/2012; · 1.98 Impact Factor
• Article: Five-Year Incidence of Age-Related Macular Degeneration: The Beijing Eye Study.

  Qi Sheng You, Liang Xu, Hua Yang, Yi Bin Li, Shuang Wang, Jin Da Wang, Jing Shang Zhang, Ya Xing Wang, Jost B Jonas
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  ABSTRACT: PURPOSE: To examine the incidence of age-related macular degeneration (AMD) and its associated factors in an adult Chinese population. DESIGN: Population-based study. PARTICIPANTS: The Beijing Eye Study, which included 4439 subjects (age ≥40 years) in 2001, was repeated in 2006 with 3251 (73.2%) subjects participating. METHODS: Fundus photographs were graded using the International Age-related Maculopathy Epidemiological Study Group grading system. MAIN OUTCOME MEASURES: Incidence of AMD. RESULTS: Gradable slides were available on 3049 (93.9%) subjects who participated in the survey of 2001 and again in 2006. The incidence of early, late, and neovascular AMD per eye was 2.6% (95% confidence interval [CI], 2.2-3.0), 0.1% (95% CI, 0.00-0.2), and 0.1% (95% CI, 0.00-0.2), respectively. The incidence of early, late, and neovascular AMD per person was 4.2±0.4% (95% CI, 3.5-5.0), 0.1±0.1% (95% CI, 0.0-0.2), and 0.1±0.1% (95% CI, 0.0-0.2), respectively. By multivariate analysis, incident early AMD was associated significantly with greater age at baseline (P = 0.01; odds ratio [OR], 1.03; 95% CI, 1.01-1.06), smaller optic disc size (P = 0.007; OR, 0.50; 95% CI, 0.30-0.83), smaller scleral spur distance (P = 0.04; OR, 0.59; 95% CI, 0.36-0.98), and hyperopic refractive error (P = 0.057; OR, 1.15; 95% CI, 1.00-1.33), with the latter being significant only marginally. It was not associated with the systemic parameters of gender, body height, body mass index, region of habitation, level of education, social class as a peasant, smoking, arterial blood pressure, diabetes mellitus, fasting blood concentrations of glucose, triglycerides, high-density or low-density lipoproteins; or the ocular parameters of intraocular pressure, retinal arterial and vein diameters, retinal microvascular abnormalities, amount of nuclear cataract, cortical cataract or subcapsular cataract, pseudophakia, glaucoma, nonglaucomatous optic neuropathy, retinal vein occlusions, size of the beta zone of parapapillary atrophy, or progression of the zone of atrophy during the follow-up from 2001 to 2006. CONCLUSIONS: Hyperopia, short interscleral spur distance, and small optic disc size were, beside older age, the main factors associated with incident early AMD. This may point to a small globe size, potentially in relation to a firmly attached vitreous, playing a role in early incident AMD. FINANCIAL DISCLOSURE(S): The authors have no proprietary or commercial interest in any of the materials discussed in this article.
  Ophthalmology 08/2012; · 5.45 Impact Factor
• Article: Cotton-wool spot and optical coherence tomography of a retinal nerve fiber layer defect.

  Li Zhang, Liang Xu, Jing-Shang Zhang, Ya-Qin Zhang, Hua Yang, Jost B Jonas
  Archives of ophthalmology 07/2012; 130(7):913. · 3.86 Impact Factor
• Article: Sr microalloying for refining grain size of AZ91D Magnesium alloy

  Yichuan Pan, Xiangfa Liu, Hua Yang
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  ABSTRACT: The grain refining process of an AZ91D Mg alloy by Sr addition was studied and the heterogeneous nucleating particles of α-Mg were investigated by electron probe microanalysis (EPMA). With 0.6 wt% Sr addition, the mean grain size of AZ91D alloy was refined from 235.4 μm to 52.5 μm at the one-half radius of the ingot. The morphology of primary crystal changed from a sixford symmetrical shape to a petal-like shape. Mg-Sr-Al-Fe-Mn heterogeneous nucleating particles were observed at the grain centers and Sr solute atoms presented segregation along the grain boundaries. Grain refinement was facilitated by both the Mg-Sr-Al-Fe-Mn nucleating particles and the Sr solute atoms, and the former played a dominate role in the process.
  Journal of Wuhan University of Technology-Mater Sci Ed 04/2012; 22(1):74-76. · 0.35 Impact Factor
• Article: Luminescent properties of codoping Y2O3: Eu, Me (Me = Mg, Ca) nanorods

  Zhilong Liu, Qin Wang, Yuming Yang, Chunyan Tao, Hua Yang
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  ABSTRACT: Phosphors of nanorods Y2O3: Eu (Mg, Ca) have been prepared by the hydrothermal method. The effect of Mg, Ca co-dopants on the Y2O3: Eu phosphor photoluminescence (PL) property was investigated. Upon excitation with ultraviolet (UV) irradiation, it is shown that there is a strong emission at around 610nm corresponding to the forced electric dipole 5D0–7F2 transition of Eu3+. At a certain concentration, Mg, Ca ions’ doping effectively enhanced the luminescent properties of Y2O3: Eu3+ nanorods and did not change the cubic phase of the host. The structure of Y2O3: Eu3+ (Mg, Ca) phosphors was characterized by X-Ray diffraction (XRD). From XRD patterns, it is indicated that the phosphor Y2O3:(Eu, Ca) forms without impurity phase. From SEM, TEM images, it is shown that the crystal size of the nanorods phosphors is about 1–2μm in length and 30–50nm in diameter. KeywordsY2O3 Eu-Luminescence-Codoped Mg Ca-Nanorod
  Journal of Nanoparticle Research 04/2012; 12(6):2233-2240. · 3.29 Impact Factor
• Source

  Available from: nanoarchive.org

  Article: Effect of lanthanum ions on magnetic properties of Y3Fe5O12 nanoparticles

  Zhongjun Cheng, Yuming Cui, Hua Yang, Yan Chen
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  ABSTRACT: Lanthanum ion (La3+)-substituted garnet nanoparticles Y3−x La x Fe5O12 (x=0.0, 0.2, 0.4, 0.6, 0.8, and 1.0) were fabricated by a sol–gel method. Their crystalline structures and magnetic properties were investigated by using X-ray diffraction (XRD), vibrating sample magnetometer (VSM), and Mössbauer spectrum. The XRD results show that samples of Y3−x La x Fe5O12 (0.0≤x≤0.8) are all single phase and the sizes of particles range from 32 to 65nm. Those of Y2LaFe5O12 consisted of peaks from garnet and LaFeO3 structures. Compared to pure YIG, the saturation magnetization is larger when the La concentration x=0.2. However, with increasing La concentration (x), it decreases obviously. Meanwhile, may be due to the enhancement of the surface spin effects, the saturation magnetization rises as the particle size is increased. Different from the pure YIG, the Mössbauer spectra of Y2.8La0.2Fe5O12 and Y2.2La0.8Fe5O12 are composed of four sets of six-line hyperfine patterns. The results tell us that the substitution of La3+ ions with large ionic radius (1.061Å) will give rise to a microscopic structure distortion of the a- and d-sites to different degrees, and the Zeeman sextets from a- and d-sites begin to split into two sub-sextets, which is helpful to explain the phenomenon observed in the study of the magnetic property.
  Journal of Nanoparticle Research 04/2012; 11(5):1185-1192. · 3.29 Impact Factor
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  Available from: nanoarchive.org

  Article: Morphology and magnetic properties of FexCo1−x/CoyFe3−yO4 nanocomposites prepared by surfactants-assisted-hydrothermal process

  Qin Wang, Hua Yang
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  ABSTRACT: Recently, we have demonstrated the successful synthesis of Fe x Co1−x /Co y Fe3−y O4 nanocomposites with various alkaline solutions by using surfactants-assisted-hydrothermal (SAH) process. In this article, the synthesis of Fe x Co1−x /CoyFe3−y O4 nanocomposites with their sizes varying between 20nm and 2μm was reported. X-ray powder diffraction (XRD) analyses showed that the surfactants, pH, precipitator, and temperature of the system play important roles in the nucleation and growth processes. The magnetic properties tested by vibrating sample magnetometer (VSM) at room temperature exhibit ferromagnetic behavior of the nanocomposites. These Fe x Co1−x /Co y Fe3−y O4 nanocomposites may have a potential application as magnetic carriers for drug targeting because of their excellent soft-magnetic properties.
  Journal of Nanoparticle Research 04/2012; 11(5):1043-1051. · 3.29 Impact Factor
• Article: Anterior visual pathway assessment by magnetic resonance imaging in normal-pressure glaucoma.

  Ya Q Zhang, Jing Li, Liang Xu, Li Zhang, Zhen C Wang, Hua Yang, Chang X Chen, Xi S Wu, Jost B Jonas
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  ABSTRACT: PURPOSE: To analyze the axonal architecture of the optic nerve in patients with normal-pressure glaucoma and determine whether these parameters correlate with the disease severity. Methods:  Using magnetic resonance (MRI) imaging (1.5-Tesla unit) and diffusion tensor (DT) MRI, we measured the optic nerve diameter, optic chiasm height and lateral geniculate nucleus (LGN) volume in patients with normal-pressure glaucoma and an age-matched control group. The retinal nerve fibre layer thickness (RNFL) was determined by optical coherence tomography (OCT). Results:  The study included 30 patients with normal-pressure glaucoma and 30 age-matched control subjects. Optic nerve diameter (p < 0.001), optic chiasm height (p < 0.001) and LGN volume (p = 0.02) were significantly smaller in the glaucoma group than in the control group and were significantly correlated with RNFL thickness and perimetric loss. In the control group, the parameters significantly (p < 0.05) decreased with age. The DT-MRI-derived fractional anisotropy for the optic nerve was significantly lower (p < 0.001), and the DT-MRI-derived mean diffusivity (p < 0.001), radial diffusivity (λ(⊥) ; p < 0.001) and axial diffusivity (λ(||) ; p = 0.009) for the optic nerve were significantly higher in the glaucoma group and significantly correlated with RNFL thickness and mean perimetric defect. Conclusions:  Patients with normal-pressure glaucoma show an age-adjusted reduced optic nerve diameter, optic chiasm height and LGN volume as measured by MRI, correlating with a reduced RNFL thickness and increased perimetric loss. MRI may be applied to examine the optic nerve in patients with glaucoma with opaque optic media.
  Acta ophthalmologica 04/2012; 90(4):e295-302. · 2.44 Impact Factor
• Source

  Available from: Yiyun Zhang

  Article: Light extraction efficiency improvement by multiple laser stealth dicing in InGaN-based blue light-emitting diodes.

  Yiyun Zhang, Haizhong Xie, Haiyang Zheng, Tongbo Wei, Hua Yang, Jing Li, Xiaoyan Yi, Xiangyang Song, Guohong Wang, Jinmin Li
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  ABSTRACT: We report a multiple laser stealth dicing (multi-LSD) method to improve the light extraction efficiency (LEE) of InGaN-based light-emitting diodes (LEDs) using a picosecond (Ps) laser. Compared with conventional LEDs scribed by a nanosecond (Ns) laser and single stealth-diced LEDs, the light output power (LOP) of the LEDs using multi-LSD method can be improved by 26.5% and 11.2%, respectively. The enhanced LOP is due to the increased side emission from the large-area roughened sidewalls of the sapphire substrates fabricated in the multi-LSD process. Numerical simulation results show that the multi-LSD process has little thermal damages to the multiple quantum wells (MQWs) of the LEDs.
  Optics Express 03/2012; 20(6):6808-15. · 3.59 Impact Factor
• Article: Beijing Eye Public Health Care Project.

  Liang Xu, Jost B Jonas, Tong Tong Cui, Qi Sheng You, Ya Xing Wang, Hua Yang, Jian Jun Li, Wen Bin Wei, Qing Feng Liang, Shuang Wang, Xiao Hui Yang, Li Zhang
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  ABSTRACT: The Beijing Eye Public Health Care Project was designed to screen all elderly subjects (age 55-85 years) of the rural region of Greater Beijing. It was developed as a preparatory step for a telemedicine-based public health care system in ophthalmology in China. Population-based public health care project. Elderly subjects (age 55-85 years) of the rural region of Greater Beijing. Project participants were visited, interviewed, and examined by 2500 high school graduates trained as ophthalmic technicians. If visual acuity was <0.30, subjects were referred to primary health care centers where ocular photographs were taken. Using telemedicine, the photographs were transmitted to a reading center and causes for visual impairment were diagnosed. Practicability of a mass screening system in ophthalmology; prevalence of visual impairment and causes for it. Out of 692 323 eligible inhabitants, 562 788 (81.3%) subjects participated. Visual impairment in ≥1 eye was detected in 54 155 (9.62%) subjects, and among them, 30 164 (5.36%) subjects had bilateral visual impairment. Ocular fundus photographs were taken for 37 281 subjects. Cause for visual impairment was cataract in 19 163 (3.41%) of all screened subjects, glaucoma in 1606 (0.29%) subjects, diabetic retinopathy in 905 (0.16%) subjects, other macular diseases in 2700 (0.48%) subjects, pterygium in 1381 (0.25%) subjects, and corneal leukoma in 283 (0.05%) subjects. For 5853 (1.04%) subjects, a diagnosis of premature or mature cataract was made showing the urgent need of cataract surgery. After cataract surgery, visual acuity was ≥0.30 in 1464 (91.7%) of 1596 postoperatively reexamined subjects. Using a telemedicine approach, the Beijing Eye Public Health Care Project developed, applied and tested an infrastructure for ophthalmic mass screening of >500 000 elderly inhabitants with a response rate of >80%. Beside cataract, retinal diseases including diabetic retinopathy and glaucoma were major causes for visual impairment. The authors have no proprietary or commercial interest in any of the materials discussed in this article.
  Ophthalmology 03/2012; 119(6):1167-74. · 5.45 Impact Factor
• Article: Frequency and associated factors of structural progression of open-angle glaucoma in the Beijing Eye Study.

  Ya X Wang, Lian N Hu, Hua Yang, Jost B Jonas, Liang Xu
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  ABSTRACT: To examine factors associated with progression of open-angle glaucoma in a population-based setting. The population-based Beijing Eye Study, which included 4439 subjects with an age of 40+ years in the year 2001, was repeated in 2006. Optic disc photographs of the baseline examination versus follow-up examination were compared. Out of 111 open-angle glaucoma patients examined in 2001, 77 (69%) subjects participated in the follow-up examination and 16 (21%) eyes showed glaucoma progression. Glaucoma progression was associated with smaller rim area (p=0.001), larger β zone (p=0.037), higher frequency of β zone increase during follow-up (p=0.01), higher prevalence of disc haemorrhages (p=0.01) and higher single intraocular pressure (p=0.04). In multiple regression analysis, only smaller rim area remained significantly associated with glaucoma progression. Glaucoma progression was not associated with optic disc size (p=0.70), mean blood pressure (p=0.43), ocular perfusion pressure (p=0.96), retinal vessel diameter and retinal microvascular abnormalities (all p>0.10), prevalence of diabetes mellitus (p=0.75) and arterial hypertension (p=0.26), prevalence of dyslipidaemia (p=0.28), refractive error (p=0.69), and central corneal thickness (p=0.97). In a population-based setting in adult Chinese, factors showing an association with open-angle glaucoma progression were an advanced stage of the disease (ie, small rim), presence of disc haemorrhages, larger area of β zone and higher frequency of β zone increase, and higher intraocular pressure. Glaucoma progression was not significantly associated with optic disc size, central corneal thickness, retinal vessel diameter and retinal microvascular abnormalities, and systemic diseases such as diabetes mellitus and arterial hypertension.
  The British journal of ophthalmology 03/2012; 96(6):811-5. · 2.92 Impact Factor