Speed Optimization in Automated Microinjection of Zebrafish Embryos

Peter C.Y. Chen,Shengfeng Zhou,Zhe Lu,Joo-Hoo Nam,Hong Luo,RuowenGe,Chong-Jin Ong,Wei Lin 제어·로봇·시스템학회 2015 International Journal of Control, Automation, and Vol.13 No.5

In this paper we formulate an optimization problem in the design of a speed trajectory for the motion of the micropipette during automated microinjection of zebrafish embryos. The objective of this optimization problem is to minimize the deformation sustained by the zebrafish embryo. We subsequently propose a solution to this optimization problem by first constructing a viscoelastic model of the zebrafish embryo, and then synthesizing an optimal speed trajectory based on a class of polynomials. Furthermore, we present results of numerical simulation and experiments that demonstrate the effectiveness of the proposed solution. The statistically meaningful experimental data (generated using a large sample of zebrafish embryos) provide direct evidence on the advantage of such speed optimization in microinjection.

A case study of competing risk analysis in the presence of missing data

Limei Zhou,Peter C. Austin,Abdel-Qadir 한국통계학회 2023 Communications for statistical applications and me Vol.30 No.1

Observational data with missing or incomplete data are common in biomedical research. Multiple imputation is an effective approach to handle missing data with the ability to decrease bias while increasing statistical power and efficiency. In recent years propensity score (PS) matching has been increasingly used in observational studies to estimate treatment effect as it can reduce confounding due to measured baseline covariates. In this paper, we describe in detail approaches to competing risk analysis in the setting of incomplete observational data when using PS matching. First, we used multiple imputation to impute several missing variables simultaneously, then conducted propensity-score matching to match statin-exposed patients with those unexposed. Afterwards, we assessed the effect of statin exposure on the risk of heart failure-related hospitalizations or emergency visits by estimating both relative and absolute effects. Collectively, we provided a general methodological framework to assess treatment effect in incomplete observational data. In addition, we presented a practical approach to produce overall cumulative incidence function (CIF) based on estimates from multiple imputed and PS-matched samples.

Seismic wave propagation through surface basalts - implications for coal seismic surveys

Sun, Weijia,Zhou, Binzhong,Hatherly, Peter,Fu, Li-Yun Korean Society of Earth and Exploration Geophysici 2010 지구물리와 물리탐사 Vol.13 No.1

Seismic reflection surveying is one of the most widely used and effective techniques for coal seam structure delineation and risk mitigation for underground longwall mining. However, the ability of the method can be compromised by the presence of volcanic cover. This problem arises within parts of the Bowen and Sydney Basins of Australia and seismic surveying can be unsuccessful. As a consequence, such areas are less attractive for coal mining. Techniques to improve the success of seismic surveying over basalt flows are needed. In this paper, we use elastic wave-equation-based forward modelling techniques to investigate the effects and characteristics of seismic wave propagation under different settings involving changes in basalt properties, its thickness, lateral extent, relative position to the shot position and various forms of inhomogeneity. The modelling results suggests that: 1) basalts with high impedance contrasts and multiple flows generate strong multiples and weak reflectors; 2) thin basalts have less effect than thick basalts; 3) partial basalt cover has less effect than full basalt cover; 4) low frequency seismic waves (especially at large offsets) have better penetration through the basalt than high frequency waves; and 5) the deeper the coal seams are below basalts of limited extent, the less influence the basalts will have on the wave propagation. In addition to providing insights into the issues that arise when seismic surveying under basalts, these observations suggest that careful management of seismic noise and the acquisition of long-offset seismic data with low-frequency geophones have the potential to improve the seismic results.

Characterization of AJH-836, a diacylglycerol-lactone with selectivity for novel PKC isozymes

Cooke, Mariana,Zhou, Xiaoling,Casado-Medrano, Victoria,Lopez-Haber, Cynthia,Baker, Martin J.,Garg, Rachana,Ann, Jihyae,Lee, Jeewoo,Blumberg, Peter M.,Kazanietz, Marcelo G. American Society for Biochemistry and Molecular Bi 2018 The Journal of biological chemistry Vol.293 No.22

<P>Diacylglycerol (DAG) is a key lipid second messenger downstream of cellular receptors that binds to the C1 domain in many regulatory proteins. Protein kinase C (PKC) isoforms constitute the most prominent family of signaling proteins with DAG-responsive C1 domains, but six other families of proteins, including the chimaerins, Ras-guanyl nucleotide-releasing proteins (RasGRPs), and Munc13 isoforms, also play important roles. Their significant involvement in cancer, immunology, and neurobiology has driven intense interest in the C1 domain as a therapeutic target. As with other classes of targets, however, a key issue is the establishment of selectivity. Here, using [H-3]phorbol 12,13-dibutyrate ([H-3]PDBu) competition binding assays, we found that a synthetic DAG-lactone, AJH-836, preferentially binds to the novel PKC isoforms PKC and PKCE relative to classical PKC and PKCII. Assessment of intracellular translocation, a hallmark for PKC activation, revealed that AJH-836 treatment stimulated a striking preferential redistribution of PKCE to the plasma membrane relative to PKC. Moreover, unlike with the prototypical phorbol ester phorbol 12-myristate 13-acetate (PMA), prolonged exposure of cells to AJH-836 selectively down-regulated PKC and PKCE without affecting PKC expression levels. Biologically, AJH-836 induced major changes in cytoskeletal reorganization in lung cancer cells, as determined by the formation of membrane ruffles, via activation of novel PKCs. We conclude that AJH-836 represents a C1 domain ligand with PKC-activating properties distinct from those of natural DAGs and phorbol esters. Our study supports the feasibility of generating selective C1 domain ligands that promote novel biological response patterns.</P>

Workplace harassment among staff in higher education: a systematic review

Marcus A. Henning,Chen Zhou,Peter Adams,Fiona Moir,Jennifer Hobson,Charlene Hallett,Craig S. Webster 서울대학교 교육연구소 2017 Asia Pacific Education Review Vol.18 No.4

Workplace harassment in higher education adversely impacts workforce productivity and has deleterious health effects on victims. The aim of this study was to review the literature pertaining to workplace harassment in higher education. This systematic literature search was conducted in December 2013 and completed in January 2014. Refereed journal publications from 1994 to 2013 inclusive were identified. The strategy was conducted on seven major databases. A total of 3278 articles were initially screened, and after review 51 refereed journal articles were included in the final analysis. A thematic analysis identified six themes: causation, types, employee roles, measurement, consequences and interventions. The published evidence, mainly from North America, suggests that workplace harassment is prevalent in higher education, such as gender harassment, workplace bullying, and mobbing. This review highlighted issues associated with: (1) confirming direct causation of harassment due to the high prevalence of correlational research in this area; (2) establishing and standardising measures of harassment that would have cross-cultural applicability and validity; (3) the demand for more comparative research to cater for the globally mobile workforce; (4) the requirement for greater monitoring and evaluation of the efficacy of policies and programmes purporting to be effective in dealing with harassment in the higher education workplace; and (5) the need for more contextually laden research to examine the unique nuances operating in countries, such as those in the Asia Pacific region, not well represented in the literature.

Seismic wave propagation through surface basalts – implications for coal seismic surveys

Weijia Sun,Binzhong Zhou,Peter Hatherly,Li-Yun Fu 한국지구물리.물리탐사학회 2010 지구물리와 물리탐사 Vol.13 No.1

Seismic reflection surveying is one of the most widely used and effective techniques for coal seam structure delineation and risk mitigation for underground longwall mining. However, the ability of the method can be compromised by the presence of volcanic cover. This problem arises within parts of the Bowen and Sydney Basins of Australia and seismic surveying can be unsuccessful. As a consequence, such areas are less attractive for coal mining. Techniques to improve the success of seismic surveying over basalt flows are needed. In this paper, we use elastic wave-equation-based forward modelling techniques to investigate the effects and characteristics of seismic wave propagation under different settings involving changes in basalt properties, its thickness,lateral extent, relative position to the shot position and various forms of inhomogeneity. The modelling results suggests that:1) basalts with high impedance contrasts and multiple flows generate strong multiples and weak reflectors; 2) thin basalts have less effect than thick basalts; 3) partial basalt cover has less effect than full basalt cover; 4) low frequency seismic waves (especially at large offsets) have better penetration through the basalt than high frequency waves; and 5) the deeper the coal seams are below basalts of limited extent, the less influence the basalts will have on the wave propagation. In addition to providing insights into the issues that arise when seismic surveying under basalts, these observations suggest that careful management of seismic noise and the acquisition of long-offset seismic data with low-frequency geophones have the potential to improve the seismic results.

Biomaterials-based Approaches for Cardiac Regeneration

Samhita Vasu,Justin Zhou,Jeffrey Chen,Peter V. Johnston,Deok-Ho Kim 대한심장학회 2021 Korean Circulation Journal Vol.51 No.12

The limited ability of cardiomyocytes to proliferate is a major cause of mortality and morbidity in cardiovascular diseases. There exist therapies for cardiac regeneration that are cell-based as well as that involve bioactive molecules. However, delivery remains one of the major challenges impeding such therapies from having clinical impact. Recent advancements in biomaterials-based approaches for cardiac regeneration have shown promise in clinical trials and animal studies in improving cardiac function, promoting angiogenesis, and reducing adverse immune response. This review will focus on current clinical studies of three contemporary biomaterials-based approaches for cardiac regeneration (extracellular vesicles, injectable hydrogels, and cardiac patches), remaining challenges and shortcomings to be overcome, and future directions for the use of biomaterials to promote cardiac regeneration.

지표 현무암을 통해 전파하는 탄성파의 거동-석탄 탄성파탐사에 적용

( Wei Jia Sun ),( Bin Zhong Zhou ),( Peter Hatherly ),( Yun Fu Li ) 한국지구물리탐사학회 2010 지구물리와 물리탐사 Vol.13 No.1

A new species of gall midge (Diptera: Cecidomyiidae) damaging flower buds of goji berry Lycium barbarum (Solanaceae)

Ke-Long Jiao,Xiao-Yi Zhou,Hai-Li Qiao,Hao Wang,Jun Chen,Bai-Ming Liu,Wen-Jun Bu,Peter Kolesik 한국응용곤충학회 2020 Journal of Asia-Pacific Entomology Vol.23 No.4

Larvae of a previously undescribed gall midge species have been feeding within malformed flower buds of goji berry Lycium barbarum L. (Solanaceae) in China, preventing fruit development and causing damage to the fruit industry. The new species is named Gephyraulus lycantha Jiao & Kolesik, its morphology is described, the COI mitochondrial gene segment is sequenced, and the biology is outlined. In order to taxonomically accommodate the new gall midge, the scope of the genus Gephyraulus is broadened and now encompasses also species that lack dorso-apical sensoria on the female cercus.

Sleep deprivation disrupts the lacrimal system and induces dry eye disease

Sanming Li,Ke Ning,Jing Zhou,Yuli Guo,Houjian Zhang,Yu Zhu,Liying Zhang,Changkai Jia,Yongxiong Chen,Peter Sol Reinach,Zuguo Liu,Wei Li 생화학분자생물학회 2018 Experimental and molecular medicine Vol.50 No.-

Sleep deficiency is a common public health problem associated with many diseases, such as obesity and cardiovascular disease. In this study, we established a sleep deprivation (SD) mouse model using a ‘stick over water’ method and observed the effect of sleep deficiency on ocular surface health. We found that SD decreased aqueous tear secretion; increased corneal epithelial cell defects, corneal sensitivity, and apoptosis; and induced squamous metaplasia of the corneal epithelium. These pathological changes mimic the typical features of dry eye. However, there was no obvious corneal inflammation and conjunctival goblet cell change after SD for 10 days. Meanwhile, lacrimal gland hypertrophy along with abnormal lipid metabolites, secretory proteins and free amino-acid profiles became apparent as the SD duration increased. Furthermore, the ocular surface changes induced by SD for 10 days were largely reversed after 14 days of rest. We conclude that SD compromises lacrimal system function and induces dry eye. These findings will benefit the clinical diagnosis and treatment of sleep-disorder-related ocular surface diseases.