目的1)發現與中風相闋的視網膜特徵2) 利用視網膜特徵建立統計模型對老年人中風風險進行分類。 / 方法:配對病例對照研究。病例為中風患者，一部分中風患者來自於糖尿病眼病的篩查項目，另外一部分是腦內科的中風患者。對照是沒有中風的老年人。對照來自糖尿病眼病篩查項目內沒有患中風的患者及在眼科門診沒有中風及特殊眼病的患者。對照與病例在年齡及是否患有糖尿病進行匹配。所有研究對象均來自香港威爾斯親王醫院。我們收集所有研究對象的中風危險因素，包括年齡，性別，吸煙，及是否患有糖尿病，高血壓，缺血性心髒病，心房顫動，高血脂。所有研究對象的彩色視網膜照片都被採集。我們應用軟件“ImageJ"分析並記錄視網膜動靜脈直徑，血管分叉係數，分叉角度，分叉對稱性，視乳頭周長。我們也記錄其他視網膜特徵，如動靜脈壓跡，出血，硬性滲出，動脈阻塞及血管彎曲性。獨立t檢驗用於對連續變量的單因素分析，卡方檢驗用於對分類變量的單因素分析。Logistic 回歸用於建立統計模型對中風風險進行分類。所有統計方法均應用SPSS16.0 軟件。 / 結果:本研究納入122 中風患者及122 例患者做對照。每組分別有81 例糖尿病患者， 41 例非糖尿病患者。視網膜特徵包括動靜脈直徑，血管彎曲度，出血，硬性滲出，動靜脈壓跡在兩組中有顯著性差異。我們建立風險模型對兩組患者進行風險分類。分類準確度最高達的模型裡面包括的因子有：1)中風相關危險因素包括:高血壓，糖尿病，心房顫動2) 視網膜特徵包括:動脈直徑，血管彎曲性，出血，動靜脈壓跡跟靜脈對稱性；3) 視網膜特徵間的交立作用包括:動脈直徑與靜脈對稱性，動脈直徑與出血，靜脈對稱性與血管彎曲度。分類的準確度為80 .4%。只包括視網膜特徵的分類模型的準確度為74.5% 。 / 結論:彩色視網膜照相可成為中風風險的分類工具。與中風相關的視網膜特徵包括血管直徑，血管彎曲度，血管對稱性，出血，動靜脈壓跡。視網膜特徵與中風之間的聯繫存在交互作用。 / Objective: 1) To detect retina characteristics that associated with stroke; 2) To develop a statistics model with variables of retina characteristics for classifying patients with stroke from those without stroke in aged population. / Method: Matched case control study. Patients with stroke from the diabetic retinopathy screening program and stroke patients from Acute Stroke Unit were selected as stroke cases. Controls (patients without history of stroke) with matched diabetes status and age were selected from the diabetic retinopathy screening program and eye outpatient clinics. All subjects in this study were from Prince of Wales Hospital, Hong Kong. Risk factors of stroke from all subjects were collected, including age, gender, diabetes, hypertension, hyperlipidemia, history of ischemic heart disease, atrial fibrillation and smoking. Color retina images of each subject were collected and analyzed. The retina characteristics, including diameters of arterioles and venules, bifurcation coefficients, bifurcation angles, branch symmetry, optic disc perimeter were extracted from the color retina images by software "ImageJ". Other retina characteristics including arteriole-venule nicking, hemorrhages, exudates, arteriole occlusion, and vessel tortuosity were also recorded. Independent t test and Chi-squire test were used to compare the continuous and categorical retina characteristics respectively between patients with stroke and those without stroke. Logistic model combining the risk factors of stroke and retina characteristics was established to classify patients with stroke from those without stroke. All data analysis was by SPSS 16.0. / Results: there were 122 stroke cases and 122 controls recruited in this study. There were 41 patients without diabetes and 81 patients with diabetes in each group. Retina characteristics including diameters of arterioles and venules, vessel tortuosity, hemorrhages, exudates, arteriole-venule nicking were significantly different between the two groups. We established risk models to classify patients with stroke from those without stroke. The risk model with highest accuracy of classification included 1) stroke risk factors including hypertension, diabetes and atrial fibrillation; 2) retina characteristics, including arteriole diameters, vessel tortuosity, hemorrhages, arteriolevenule nicking and venule symmetry; 3)interaction between retina characteristics, including arteriole diameters by venule symmetry, arteriole diameters by hemorrhage,and venule symmetry by vessel tortuosity. The accuracy of classification was 80.4%. Using retinal characteristics alone achieved an accuracy of 74.5%. / Conclusion: color retina images are a potential tool for stroke risk stratification. Useful characteristics found in the retinal images included vessel diameters, vessel tortuosity, vessel symmetry, hemorrhage, arteriole-venule nicking. The association between the retinal characteristic and stroke was modified by other retinal characteristics. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Li, Qing. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 139-148). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese. / Abstract (English) --- p.i / Abstract (Chinese) --- p.iii / Acknoledgements --- p.v / Chapter Chapter 1 --- Introduction and review of the Literature --- p.1 / Chapter Section 1: --- Stroke prevention and risk assessment tools --- p.1 / Chapter Section 2: --- Rationale of relationship of vascular circulation between retina and brain --- p.9 / Chapter Section 3: --- Manifestation of hypertensive retinopathy and diabetic retinopathy --- p.12 / Chapter Section 4: --- Retina characteristics related to stroke --- p.15 / Chapter Section 5: --- How to make retina as a tool of risk stratification for stroke --- p.28 / Chapter Section 6: --- Rationale to do study to further explore the useful information in color retina images to make it as tool for stroke risk stratification --- p.31 / Chapter Chapter 2 --- Research hypothesis and general design --- p.33 / Chapter Chapter 3 --- Methods of retia characteristics extraction --- p.34 / Chapter Chapter 4 --- A Study of the Reliability of manual measurement of Retinal characteristics using ImageJ --- p.46 / Chapter Chapter 5 --- A study of comparison of retina characteristics between patients with stroke and patients without stroke --- p.55 / Chapter Section 1: --- Method --- p.56 / Chapter Section 2: --- Result-univariate analysis --- p.62 / Chapter Section 3: --- Results-stratification analysis --- p.68 / Chapter Section 4: --- Result-risk model building for stroke risk stratification --- p.79 / Chapter Chapter 6: --- Discussion --- p.118 / Chapter Chapter 7: --- Limitation of this study --- p.133 / Chapter Chapter 8: --- Future development and application of the study results --- p.134 / Appendix --- p.136 / Reference --- p.139

The thesis presents a comparison of four techniques used for stereotactic radiosurgery, consisting of the static conformal beam, static cone-based, proton therapy, and the Gamma Knife techniques. The comparisons involved six test cases in which phantom target lesions were created in the center of the modified anthropomorphic RandoRTM head. The phantom lesions presented in the study were extreme irregular cases that ranged in shape and volume and were near a critical structure to receive minimal dose during treatment planning. The best treatment plans from each technique for all studies were selected and the extracted data was analyzed using physical and biological parameters. Correlations between integral biological effective dose (normal brain) and normal tissue complication probability were analyzed as a function of dose conformity (PITV), and correlations between tumor control probability and integral biological effective dose (tumor) as a function of dose homogeneity (MDPD) were analyzed, as well. These parameter pairings showed strong links. The static conformal beam and the proton SOBP techniques consistently provided low PITV and MDPD values for all cases, including the most irregular and complicated cases. Higher PITV and MDPD values, typically associated with static cone-based and the Gamma Knife techniques, were due to normal tissue and tumor tissue, respectively, being irradiated at higher dose levels than the prescribed dose. For these cases, as the PITV increased, the NTCP increased, as well, due to high doses created within the normal tissue found within the prescription isodose surface.

In the present day Mandarin Chinese has become a commonly taught language in the U.S. Mandarin is widely taught in colleges and universities; K-12 Chinese programs, including immersion programs, have also grown rapidly. However, to date little research has been conducted on the latter programs. This study examines immersion programs in elementary schools. I investigate three aspects: 1) teaching methods in Chinese immersion programs, 2) acquisition of grammatical patterns, and 3) computer assisted methods for character learning. I adopted a qualitative approach; the methods I employ include observation, interviews, questionnaires, and tests. Data were collected from two immersion programs and two non-immersion programs in a Southwestern city in the U.S. The first study compares the teaching methods used in Chinese immersion and non-immersion programs. It is found that the two immersion programs adopted the functional approach with explicating in each class time, while the non-immersion programs used the analytical approach with practicing in context in most classes. The immersion students produced spontaneous speech in each class, while non-immersion language class students did not. The second study examines how immersion learners acquire the ba-construction and time phrases. We found that immersion students produced not many ba sentences but a large number of time phrases. However, in terms of accuracy, ba sentences were produced almost flawlessly, while time phrases were often placed incorrectly in a sentence. This result is quite different from what we find in adult learners who mostly acquire Chinese in a non-immersion setting. It shows that immersion learners’ acquisition differs from both L1 acquisition and L2 acquisition by adults. The third study investigates how computer-assisted methods help students learn Chinese characters. I compare immersion learners with heritage learners with respect to how they respond to computer-assisted methods. No difference is found between the two groups of learners in terms of their performance in character recognition, pronunciation and writing. It is also found that while computer assisted materials helped with character recognition, it did not help with character writing.

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下颌角缩小术是一种非常流行、有效、并广泛用于修饰脸部轮廓的手术方式。手术中所用到的主要工具有往复锯和圆头磨钻，这两种手术工具工作时有一个共同的特点：通过其高速运转去除骨质。缺乏经验的医生通常需要较长周期的训练，来学习和熟悉如何操作这两种手术工具，并在操作过程中避免由于无法控制好工具与骨骼的触碰以及工具运转时的在骨骼上的移动所造成的危险。具有视觉和触觉反馈的虚拟手术模拟系统为医生们练习手术技巧提供了一种可行并且安全的方式。然而，创建高速运转的手术工具与坚硬的骨骼之间的真实触觉交互模型是一个非常有挑战性的任务。 / 这篇论文设计并实现了虚拟下颌角缩小手术模拟系统，并且创建高保真度的视觉和触觉反馈来增强虚拟手术环境的真实性。文章提出了基于冲量理论的力反馈模型用来模拟作用在工具上的碰撞力和力矩。在不同的往复速率或者旋转速度的情况下，所提出的模型都可以为医生提供可信真实的力感反馈。并且针对磨钻在磨骨是震动明显对磨骨操作有较大影响的特点，论文还提出了一个三维震动模型来模拟磨骨时作用在钻轴上的橫向震动和轴向震动。同时，论文还提出了用于模拟手术中骨质去除以及重建的实时绘制方法。为了验证力模型的真实性，我们还创建了机械平台，采集磨骨和截骨过程中产生的真实力数据，从而用来与虚拟手术中产生的力数据进行比较。最后，还引入真实病人的CT扫描数据来对虚拟手术系统进行实证研究，评估创建的系统是否可以用于训练具有不同手术经验的医生。实证研究的结果也验证了所提出的虚拟手术系统的有效性。 / Mandibular angle reduction is a popular and efficient procedure widely used to alter the facial contour. The primary surgical instruments, the reciprocating saw and the round burr, employed in the surgery have a common feature: operating at a high-speed. Generally, inexperienced surgeons need a longtime practice to learn how to minimize the risks caused by the uncontrolled contacts and cutting motions in manipulation of instruments with high-speed reciprocation or rotation. Virtual reality (VR)-based surgical simulations with both visual and haptic feedbacks provide novice surgeons with a feasible and safe way to practise their surgical skill. However, creating realistic haptic interactions between a high-speed rotary or reciprocating instrument and stiff bone is a challenging task. In this work, a virtual reality-based surgical simulator for the mandibular angle reduction was designed and implemented. High-fidelity visual and haptic feedbacks are provided to enhance the perception in a realistic virtual surgical environment. The impulse-based haptic model was proposed to simulate the contact forces and torques on the instruments. It provides convincing haptic sensation for surgeons to control the instruments under different reciprocation or rotation velocities. Also, in order to mimic the lateral and axial burring vibration forces, a three dimensional vibration model has been developed. The real-time methods for bone removal and reconstruction during surgical procedures have been proposed to support realistic visual feedbacks. The simulated contact forces were verified by comparing against the actual force data measured through the constructed mechanical platform. An empirical study based on the patient-specific data was conducted to evaluate the ability of the proposed system in training surgeons with various experiences. The results confirm the validity of our simulator. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Wang, Qiong. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 100-114). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese. / Abstract --- p.i / Acknowledgement --- p.v / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Contributions of the Thesis --- p.5 / Chapter 1.2 --- Thesis Roadmap --- p.7 / Chapter 2 --- Related Work --- p.9 / Chapter 2.1 --- Virtual Orthopaedic Surgical Simulator --- p.9 / Chapter 2.2 --- Haptic Rendering for Virtual Surgery --- p.11 / Chapter 2.3 --- Evaluation of the Virtual System --- p.14 / Chapter 3 --- System Design --- p.17 / Chapter 3.1 --- Overall System Framework --- p.17 / Chapter 4 --- Bone-burring Surgical Simulation --- p.21 / Chapter 4.1 --- Impulse-Based Modeling of Haptic Simulation of Bone-Burring --- p.22 / Chapter 4.1.1 --- Basic Assumptions --- p.22 / Chapter 4.1.2 --- Bone-Burring Contact Description --- p.25 / Chapter 4.1.3 --- Burring Force Modeling --- p.29 / Chapter 4.2 --- Simulation of Bone Removal --- p.41 / Chapter 4.2.1 --- Bone Removal model --- p.41 / Chapter 4.2.2 --- Adaptive Subdividing Removal Surface --- p.42 / Chapter 4.3 --- Implementation and Experimental Results --- p.52 / Chapter 4.3.1 --- Force Evaluation --- p.53 / Chapter 4.3.2 --- Task-based Evaluation --- p.57 / Chapter 4.3.3 --- Time Performance --- p.61 / Chapter 5 --- Bone-sawing Surgical Simulation --- p.64 / Chapter 5.1 --- Impulse-Based Modeling of Haptic Simulation of Bone-Sawing --- p.65 / Chapter 5.1.1 --- Haptic Saw Instruments Description --- p.65 / Chapter 5.1.2 --- Sawing Force Modeling --- p.67 / Chapter 5.1.3 --- Sawing Torque Constraint --- p.70 / Chapter 5.2 --- Real-time Bone Mesh Reconstruction --- p.74 / Chapter 6 --- Evaluation --- p.78 / Chapter 6.1 --- Haptic Feedback Evaluation --- p.79 / Chapter 6.1.1 --- Mechanical Platform Setup --- p.79 / Chapter 6.1.2 --- Comparison of The Measured and Simulated forces --- p.81 / Chapter 6.2 --- Empirical Study --- p.85 / Chapter 6.2.1 --- Patient Specific Data --- p.87 / Chapter 6.2.2 --- Objective Performance Metrics --- p.89 / Chapter 6.2.3 --- Evaluation Results --- p.90 / Chapter 7 --- Conclusion --- p.94 / Publication List --- p.98 / Bibliography --- p.100

As hemartroses, a despeito dos avanços terapêuticos ocorridos na hemofilia, continuam sendo os eventos clínicos mais freqüentes. As hemartroses de repetição, sobretudo nos tornozelos, podem estar associadas à instabilidade articular. Sabe-se que a instabilidade articular pode contribuir para aumentar a frequência dessas complicações e prescrevem-se órteses que limitam muito os pacientes. Diante desse quadro buscamos um instrumento para qualificar os desvios nos tornozelos instáveis durante a marcha, dinamicamente e em tempo real. Essa avaliação permitiu a prescrição de palmilhas de fácil confecção, de calçados com contrafortes posteriores e, nos casos muito instáveis, a associação de órteses funcionais, dinâmicas, para tornozelos. A intervenção realizada nos pacientes constou do exame pela podobarometria dinâmica computadorizada, antes e depois da prescrição das órteses. O uso das órteses prescritas conforme as observações podobarométricas permitiu liberdade na marcha, assegurando estabilidade articular. O número de hemartroses nos tornozelos e o consumo de fatores da coagulação em cada hemorragia, nos 43 hemofílicos avaliados, foi verificado nos prontuários médicos dos pacientes, em suas instituições de origem, nos seis meses pré-intervenção e nos seis meses pós-intervenção. Nos 43 hemofílicos avaliados, a média de ocorrência de hemartroses, que era de 4,81, foi reduzida para 2,53 hemartroses por paciente, após a intervenção. A média do consumo de fatores da coagulação reduziu de 9647,7 IU para 4407,0 IU, com p<0,001 . Com base na análise dos resultados concluímos que a podobarometria dinâmica computadorizada é um meio diagnóstico útil na prescrição de estabilizadores para os tornozelos dos hemofílicos, contribuindo significantemente para a redução da incidência de hemartroses. / The haemarthrosis, despite the improvement of therapeutic resources occurred in haemophilia, have been the most frequent haemophiliac\'s clinical event. The repetitive haemarthrosis, speccialy those occurred in ankle joints, could be associated to ankle instabilities. It is known that the joint instability can contribute to increase the frequency of those complications and are prescribed orthosis which severely limit the patients. Face to these facts, we have searched for an instrument able to qualify the deviations in the unstable ankles during the gait, dynamically and in real time. Such evaluation would allow the prescription of insoles, of shoes with posterior counters and, in very unstable cases, the association of dynamic supports. The intervention performed in the patients was constituted of the computerised dynamic pedobarography examination, before and after the prescription of the orthosis. The use of the prescribed orthosis according to the pedobarographic observations allowed joint stability with gait liberty. The number of haemarthrosis in the ankles and the consumption of coagulation factors in each bleeding of the 43 haemophilic evaluated was verified in the patients\' medical records, in their original institutions, in the six months that preceded evaluation and therapeutic intervention in haemophilic patients and during the six months after it. In the 43 evaluated haemophilic patients, the average occurrence of haemarthrosis went from 4,81 episodes before intervention to 2,53 episodes after the intervention. The average coagulation factors consumption went from 9.647,7 IU to 4.407,0 IU. The p value is smaller than 0,001. Based on the analysis of the results, we are able to conclude that the computerised dynamic pedobarography is a useful diagnosis method with a significant contribution to the reduction of incidence of ankle haemarthrosis.

As hemartroses, a despeito dos avanços terapêuticos ocorridos na hemofilia, continuam sendo os eventos clínicos mais freqüentes. As hemartroses de repetição, sobretudo nos tornozelos, podem estar associadas à instabilidade articular. Sabe-se que a instabilidade articular pode contribuir para aumentar a frequência dessas complicações e prescrevem-se órteses que limitam muito os pacientes. Diante desse quadro buscamos um instrumento para qualificar os desvios nos tornozelos instáveis durante a marcha, dinamicamente e em tempo real. Essa avaliação permitiu a prescrição de palmilhas de fácil confecção, de calçados com contrafortes posteriores e, nos casos muito instáveis, a associação de órteses funcionais, dinâmicas, para tornozelos. A intervenção realizada nos pacientes constou do exame pela podobarometria dinâmica computadorizada, antes e depois da prescrição das órteses. O uso das órteses prescritas conforme as observações podobarométricas permitiu liberdade na marcha, assegurando estabilidade articular. O número de hemartroses nos tornozelos e o consumo de fatores da coagulação em cada hemorragia, nos 43 hemofílicos avaliados, foi verificado nos prontuários médicos dos pacientes, em suas instituições de origem, nos seis meses pré-intervenção e nos seis meses pós-intervenção. Nos 43 hemofílicos avaliados, a média de ocorrência de hemartroses, que era de 4,81, foi reduzida para 2,53 hemartroses por paciente, após a intervenção. A média do consumo de fatores da coagulação reduziu de 9647,7 IU para 4407,0 IU, com p<0,001 . Com base na análise dos resultados concluímos que a podobarometria dinâmica computadorizada é um meio diagnóstico útil na prescrição de estabilizadores para os tornozelos dos hemofílicos, contribuindo significantemente para a redução da incidência de hemartroses. / The haemarthrosis, despite the improvement of therapeutic resources occurred in haemophilia, have been the most frequent haemophiliac\'s clinical event. The repetitive haemarthrosis, speccialy those occurred in ankle joints, could be associated to ankle instabilities. It is known that the joint instability can contribute to increase the frequency of those complications and are prescribed orthosis which severely limit the patients. Face to these facts, we have searched for an instrument able to qualify the deviations in the unstable ankles during the gait, dynamically and in real time. Such evaluation would allow the prescription of insoles, of shoes with posterior counters and, in very unstable cases, the association of dynamic supports. The intervention performed in the patients was constituted of the computerised dynamic pedobarography examination, before and after the prescription of the orthosis. The use of the prescribed orthosis according to the pedobarographic observations allowed joint stability with gait liberty. The number of haemarthrosis in the ankles and the consumption of coagulation factors in each bleeding of the 43 haemophilic evaluated was verified in the patients\' medical records, in their original institutions, in the six months that preceded evaluation and therapeutic intervention in haemophilic patients and during the six months after it. In the 43 evaluated haemophilic patients, the average occurrence of haemarthrosis went from 4,81 episodes before intervention to 2,53 episodes after the intervention. The average coagulation factors consumption went from 9.647,7 IU to 4.407,0 IU. The p value is smaller than 0,001. Based on the analysis of the results, we are able to conclude that the computerised dynamic pedobarography is a useful diagnosis method with a significant contribution to the reduction of incidence of ankle haemarthrosis.

PURPOSE: To investigate cerebrospinal fluid (CSF) dynamics in the aqueduct of Sylvius in multiple sclerosis (MS) patients and healthy controls (HC) using cine phase contrast imaging. MATERIALS AND METHODS: In all, 67 MS patients (48 relapsing-remitting [RR] and 19 secondary-progressive [SP]), nine patients with clinically isolated syndrome (CIS), and 35 age- and sex-matched HC were examined. CSF flow and velocity measures were quantified using a semiautomated method and compared with clinical and magnetic resonance imaging (MRI) disease outcomes. RESULTS: Significantly decreased CSF net flow was detected in MS patients compared to HC (-3.7 vs. -7.1 muL/beat, P = 0.005). There was a trend for increased net positive flow between SP, RR, and CIS patients. Altered CSF flow and velocity measures were associated with more severe T1 and T2 lesion volumes, lateral and fourth ventricular volumes, and third ventricular width in MS and CIS patients (P < 0.01 for all). In CIS patients, conversion to clinically definite MS in the following year was related to decreased CSF net flow (P = 0.007). There was a trend between increased annual relapse rate and altered CSF flow/velocity measures in RRMS patients (P < 0.05). CONCLUSION: CSF flow dynamics are altered in MS patients. More severe clinical and MRI outcomes in RRMS and CIS patients relate to altered CSF flow and velocity measures.