ON TESTING FOR HOMOGENEITY OF THE COVARIANCE N\MATRICES

Zhang, Xiao-Ning,Jing, Ping,Ji, Xiao-Ming 한국전산응용수학회 2001 The Korean journal of computational & applied math Vol.8 No.2

Testing equality of covariance matrix of k populations has long been an interesting issue in statistical inference. To overcome the sparseness of data points in a high-dimensional space and deal with the general cases, we suggest several projection pursuit type statistics. Some results on the limiting distributions of the statistics are obtained. some properties of Bootstrap approximation are investigated. Furthermore, for computational reasons an approximation which is based on Number theoretic method for the statistics is adopted. Several simulation experiments are performed. AMS Subject Classification : 2H15, 62H10, 62G09, 62G10

Elucidations of weak microcavity effect and improved pixel contrast ratio in Si-based top-emitting organic light-emitting diode

Xiao-Wen Zhang,Hua-Ping Lin,Jun Li,Fan Zhou,Bin Wei,Xue-Yin Jiang,Zhi-Lin Zhang 한국물리학회 2012 Current Applied Physics Vol.12 No.5

Microcavity effect and pixel contrast ratio (PCR) are key issues for top-emitting organic light-emitting diode (TOLED). Si and Ag are two widely used reflective anodes for constructing effective TOLEDs. The mechanism contributing to microcavity effect and PCR has been clarified by using conventional optoelectronic theory. Consequently, the differences of microcavity effect and PCR between Si-based and Agbased TOLEDs are discovered. Our results indicate that the Si-based TOLED possesses weak microcavity effect and improved PCR in comparison with Ag-based device. This is resulted from the low reflectivity and less reflective phase change of Si. The weak microcavity effect in Si-based TOLED also contributes to negligible variation of electroluminescent spectra with viewing angles and low device efficiency. Furthermore, Si-based TOLED shows rather high PCR which is about quintuple that of Ag-based device. Microcavity effect and pixel contrast ratio (PCR) are key issues for top-emitting organic light-emitting diode (TOLED). Si and Ag are two widely used reflective anodes for constructing effective TOLEDs. The mechanism contributing to microcavity effect and PCR has been clarified by using conventional optoelectronic theory. Consequently, the differences of microcavity effect and PCR between Si-based and Agbased TOLEDs are discovered. Our results indicate that the Si-based TOLED possesses weak microcavity effect and improved PCR in comparison with Ag-based device. This is resulted from the low reflectivity and less reflective phase change of Si. The weak microcavity effect in Si-based TOLED also contributes to negligible variation of electroluminescent spectra with viewing angles and low device efficiency. Furthermore, Si-based TOLED shows rather high PCR which is about quintuple that of Ag-based device.

Involvement of ER–calreticulin–Ca²⁺ signaling in the regulation of porcine oocyte meiotic maturation and maternal gene expression

Zhang, Ding-Xiao,Li, Xiao-Ping,Sun, Shao-Chen,Shen, Xing-Hui,Cui, Xiang-Shun,Kim, Nam-Hyung Wiley Subscription Services, Inc., A Wiley Company 2010 Molecular reproduction and development Vol.77 No.5

<P>Calcium is one of the most ubiquitous signaling molecules, and controls a wide variety of cellular processes. It is mainly stored in the endoplasmic reticulum (ER), bound to lumenal proteins. Calreticulin is the major Ca<SUP>2+</SUP>-binding chaperone in oocytes, and is integral to numerous cellular functions. To better understand the role of the ER– calreticulin–Ca<SUP>2+</SUP> pathway in oocyte maturation and early embryogenesis, we characterized the porcine calreticulin gene and investigated its expression profile during oocyte maturation and early embryonic development. Calreticulin was widely expressed in pig tissues and its transcripts were downregulated during maturation, especially at 44 hr, and were undetectable at the blastocyst stage. We also investigated the effect of increased cytosolic Ca<SUP>2+</SUP> induced by the Ca<SUP>2+</SUP>-ATPase inhibitor, cyclopiazonic acid (CPA), on pig oocyte maturation and maternal gene expression. CPA at 10 µM did not inhibit germinal vesicle breakdown, but did result in the arrest of 38.6% oocytes at or before the MI stage. In addition, expression of the maternal genes C-mos, BMP15, GDF9, and Cyclin B1 was significantly increased in CPA-treated MII oocytes compared with control groups. These data were supported by the results of poly(A)-test PCR, which revealed that the cyclin B1 short isoform (CB-S), GDF9, and C-mos underwent more intensive polyadenylation modification in CPA-treated oocytes than control oocytes, suggesting that polyadenylation may influence Ca<SUP>2+</SUP>-modulated changes in gene expression. Furthermore, CPA treatment decreased the percentage of four-cell parthenotes that developed into blastocysts, suggesting the need for functional SR/ER Ca<SUP>2+</SUP>-ATPase pumps or Ca<SUP>2+</SUP> signals during early embryo development after zygotic genome activation. Together, these data indicate that ER–calreticulin-associated Ca<SUP>2+</SUP> homeostasis plays a role in oocyte and embryo development, and that alterations in maternal gene expression may contribute to the underlying molecular mechanism, at least partially, via polyadenylation. Mol. Reprod. Dev. 77: 462–471, 2010. © 2010 Wiley-Liss, Inc.</P>

Reliable control of magnetic vortex chirality in asymmetrically optimized magnetic nanodisk

Zhang Huanhuan,Yu Hai,Zhang Xue-Feng,Yang Xiao-Xue,Shim Je-Ho,Ma Xiao-Ping,Piao Hong-Guang 한국물리학회 2022 Current Applied Physics Vol.43 No.-

Magnetic vortex has attracted attention in the field of information storage because their topological spin structures with chiral bistable states. If the vortex core polarity and vortex circulation sense can be controlled simultaneously in a nanodisk, which will be more beneficial to realize the multi-bit ultrahigh density storage. In this paper, a reliable control scheme for magnetic vortex chirality is proposed by optimizing the structure of Pac- Man-like nanodisk. The results show that the polarity and circulation of the vortex can be controlled simultaneously by changing the direction of the global magnetic field, and even the chiral states of the vortex can be determined by detecting the stray field distribution on the surface of the nanodisk. The optimized Pac-Man-like nanodisk provide an experimental method for the control and detection of magnetic vortex chirality, which will be beneficial to the realization of multi-bit magnetic storage or magnetic logic technology in the future.

Perioperative Comprehensive Supportive Care Interventions for Chinese Patients with Esophageal Carcinoma: a Prospective Study

Zhang, Xiao-Dan,Zhao, Qing-Yu,Fang, Yi,Chen, Guan-Xuan,Zhang, Hui-Fang,Zhang, Wen-Xiao,Yang, Xiao-Ping Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.12

Objective: To assess the effects of perioperative comprehensive supportive care interventions on outcome of Chinese esophageal cancer patients in a prospective study. Methods: 60 patients with primary esophageal carcinoma were randomized into an intervention group (IG, n=31) and a control group (CG, n=29). The Chinese version of symptom checklist-90 (SCL-90) was adopted to assess their psychological status. The interventions, including health education, psychological support, stress management, coping strategies and behavior training, were carried out in 3 phases (preoperative, postoperative I and postoperative II), and psychological effects were thereafter evaluated accordingly before surgery, and 1 week, 4 weeks and 24 weeks post-surgery. Medical costs were estimated at discharge. Survival of patients was estimated each year post-surgery. General health status and satisfaction-with-hospital were surveyed by a follow-up questionnaire 4 years post-surgery. Results: All the subjects demonstrated higher scores in the preoperative phase than the normal range of Chinese population concerning 7 psychological domains including somatization, obsessive-compulsive, depression, anxiety, hostility, phobic anxiety and paranoid ideation. Although no significant difference was observed between the two groups at admission, the scores of IG, which tended to decrease at a faster rate, were generally lower than those of CG at weeks 1, 4 and 24 post-surgery. The length of hospital stay and medical costs of IG were significantly less than those of CG and satisfaction-with-hospital was better. However, there was no significant difference in 4-year survival or health status between two groups. Conclusions: Appropriate perioperative comprehensive supportive care interventions help to improve the psychological state of Chinese patients with esophageal carcinoma, to reduce health care costs and to promote satisfaction of patients and their families with hospital.

Design and construction of shaft for rock caverns in Singapore

Zhang, Xiao-Ping,Lu, Ming,Mao, Dawei,Zhao, Zhiye,Hao, Liu Techno-Press 2017 Geomechanics & engineering Vol.13 No.1

Access shaft is of critical importance to the construction and operation of underground rock caverns. It usually has a relatively large cross-section and penetrates through fill materials, soil layers, and weathered rocks before reaching the caverns excavated in solid bedrock. In this paper, the design and construction of vertical shafts are reviewed in terms of diameter, depth, geological conditions, and support structure. Three shaft alternatives, namely alternative I: vertical shaft with spiral roads, alternative II: upper shaft with spiral roads & lower tunnels, alternative III: plain shaft, are proposed based on a simplified geological profile of the Jurong formation, Singapore. The advantages and limitations of the three types of shafts are discussed. The key issues relating to shaft design and construction, such as the shaft sinking, water control, support structure, are also discussed with a series of solutions provided, such as the sequential excavation, pre-grouting and diaphragm walls.

A high performance of BPhen-based white organic light-emitting devices with a dual-emitting layer and its electroluminescent spectral property

Hua-Ping Lin,Fan Zhou,Jun Li,Xiao-Wen Zhang,Dong-Bin Yu,Liang Zhang,Xue-Yin Jiang,Zhi-Lin Zhang 한국공업화학회 2011 Journal of Industrial and Engineering Chemistry Vol.17 No.4

This work demonstrated the fabrication of white organic light-emitting devices (WOLEDs) using a dual emitting layer (d-EML) consisting of blue and ‘white’ emitters. In this d-EML system, the blue emitter not only emits but also assists the incomplete energy transfer. More importantly, it behaves as an effective trapping site for holes, which contributes to the efficient recombination of electron–hole pairs. The d-EML was constructed between the hole-transmitting layer (HTL) and the electron-transmitting layer (ETL) of Alq3 and BPhen. The thickness of the blue emitter used in the d-EML devices has an important effect on chromaticity and efficiency. Through the optimization of device structure, the reasonable white emission with Commission Internationale de L’Eclairage (CIE) color coordinates of (0.33, 0.33) and little color shift was obtained. The device showed an applicable luminance with its maximum luminance of 22,874 cd/m2 at a driving voltage of 16 V. The maximum luminance efficiency was achieved 8.10 cd/A,and the maximum power efficiency was reached 5.07 Lm/W. The result is explained with the help of the excitons generation and diffusion theory. According to the theory of excitons generation and diffusion,an equation has been set up which concerns electroluminescent spectra to the thickness of the two emitters and to the exciton diffusion length.

Efficient hole injection in blue organic light-emitting devices by using a double hole injection layer to improve chromaticity and electrical characteristics

Hua-Ping Lin,Fan Zhou,Xiao-Wen Zhang,Dong-Bin Yu,Jun Li,Liang Zhang,Xue-Yin Jiang,Zhi-Lin Zhang 한국물리학회 2011 Current Applied Physics Vol.11 No.3

A double hole injection layer consisting of Ag_2O//MoO_x was applied to a 4,40-bis (2,2-diphenylvinyl)-1,10-biphenyl-based blue organic light-emitting device (OLED). The hole current injection of the devicewas improved and the performance of the blue OLED was enhanced. We have observed that the insertion of such double layer leads to a striking improvement in chromaticity and electrical characteristics. This device showed much better chromaticity and less current-induced color shift as compared to the corresponding single hole injection layer counterparts. Using this strategy, a striking improvement in the electrical properties with lower driving voltage, higher power efficiency and a weak current-induced fluorescence quenching was achieved. This could be explained by the fact that an interlayer of Ag_2O//MoO_x provided a stepped energy level which greatly facilitated hole injection and hence enhanced injection current. The result is verified by using the J―V curves of ‘only’ devices and further explained with the help of Fowler-Nordheim (F-N) tunneling theory.

The Lung Function Impairment in Non-Atopic Patients With Chronic Rhinosinusitis and Its Correlation Analysis

Linghao Zhang,Lu Zhang,Chun-Hong Zhang,Xiao-Bi Fang,Zhen-Xiao Huang,Qing -Yuan Shi,Li-Ping Wu,Peng Wu,Zhen-Zhen Wang,Zhi-Su Liao 대한이비인후과학회 2016 Clinical and Experimental Otorhinolaryngology Vol.9 No.4

Objectives. Chronic rhinosinusitis (CRS) is common disease in otorhinolaryngology and will lead to lower airway abnormality. However, the only lung function in CRS patients and associated factors have not been much studied. Methods. One hundred patients with CRS with nasal polyps (CRSwNP group), 40 patients with CRS without nasal polyps (CRSsNP group), and 100 patients without CRS were enrolled. The difference in lung function was compared. Meanwhile, CRSwNP and CRSsNP group were required to undergo a bronchial provocation or dilation test. Additionally, subjective and objective outcomes were measured by the visual analogue scale (VAS), 20-item Sino-Nasal Outcome Test (SNOT-20), Lund-Mackay score, Lund-Kennedy endoscopic score. The correlation and regression methods were used to analyze the relationship between their lung function and the above parameters. Results. The forced expiratory volume in 1 second (FEV1) and forced expiratory flow between 25% and 75% of forced vital capacity (FEF25-75) of CRSwNP group were significantly lower than other groups (P<0.05). On peak expiratory flow, there was no difference between three groups. In CRSwNP group, FEV1 was negatively correlated with peripheral blood eosinophil count (PBEC) and duration of disease (r=–0.348, P=0.013 and r=–0.344, P=0.014, respectively), FEF25-75 negatively with VAS, SNOT-20 (r=–0.490, P=0.028 and r=–0.478, P=0.033, respectively) in CRSsNP group. The incidence of positive bronchial provocation and dilation test was lower in CRSwNP group (10% and 0%, respectively), with both 0% in CRSsNP group. The multiple linear regression analysis indicated that change ratio of FEV1 before and after bronchial provocation or dilation test were correlated with PBEC in CRSwNP group (β=0.403, P=0.006). Conclusion. CRS leading to impaired maximum ventilation and small airway is associated with the existence of nasal polyp. Lung function impairments can be reflected by PBEC, duration, VAS, and SNOT-20. In CRSwNP patients, PBEC is independent predictor of FEV1 change ratio.

Annual Financial Impact of Thyroidectomies for Nodular Thyroid Disease in China

Liu, Xiao-Yun,Zhu, Li-Jun,Cui, Dai,Wang, Zhi-Xiao,Chen, Huan-Huan,Duan, Yu,Shen, Mei-Ping,Zhang, Zhi-Hong,Wang, Xiao-Dong,Chen, Jia-Wei,Alexander, Erik Karl,Yang, Tao Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.14

A large proportion of patients with thyroid nodules in China undergo thyroidectomy in order to get confirmatory histology diagnosis. The financial impact of this modality remains to be investigated. To evaluate rationality of performing thyroidectomy without a routine FNA preoperatively from the economic perspective, we conducted a retrospective, observational study of all archival thyroidectomies with records of cost per stay (CPS), cost per day (CPD) and length of stay (LOS) from 2008 to 2013 in the First Affiliated Hospital of Nanjing Medical University. We compared all the parameters between cancer and non-cancer thyroidectomies. We recruited 6, 140 thyroidectomies with valid records of CPS, CPD and LOS in this period. The CPS of cancer thyroidectomy was significantly higher than non-cancer thyroidectomy. The percentage of cancer thyroidectomy increased from 26.5% to 41.6%. The percentage of annual cost of cancer thyroidectomies rose from 30.2% to 45.2%. The LOS for cancer and non-cancer thyroidectomy decreased while the CPD increased in the past six years. The estimated national cost in 2012 for all thyroidectomies would be USD 1.86 billion with USD 1.09 billion for non-cancer thyroidectomies. We have witnessed great improvement in the healthcare for patients with thyroid nodules in China. However, given limited healthcare resources, currently thyroid FNA for more precise preoperative diagnosis may help to curb the rapidly increasing demand in healthcare costs in the future for nodular thyroid disease in China.