Langerhans' cell histiocytosis: Possible association with malignant germ cell tumour

A rare case of adult onset Langerhans' cell histiocytosis associated with dysgerminoma in a 35 year old Chinese woman is reported. The patient had a history of dysgerminoma of left ovary 15 years previously and had undergone surgery followed by radiotherapy and an uneventful recovery. She presented again in March 1994, this time with a left clavicular mass, which was shown histologically to be Langerhans' cell histiocytosis. The report illustrates the probable association between the two lesions, with some discussion on the underlying pathogenesis.published_or_final_versio

Effects of pore-channel ordering on the mechanical properties of anodic aluminum oxide nano-honeycombs

The mechanical properties of anodic aluminum oxide (AAO) nano-honeycombs with different spatial ordering of pore-channels are investigated by nanoindentation. The pore-channel ordering is systematically varied by carefully adjusting the orientation of the aluminum used for anodization. The results indicate that the strength of AAO structures increases significantly with the regularity of their pore-channel arrangement, whereas the elastic modulus is less sensitive to pore-channel regularity. © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.postprin

Total knee arthroplasty for primary knee osteoarthritis: Changing pattern over the past 10 years

Objective: To review the epidemiology of total knee arthroplasty for primary osteoarthritis and the change of patient characteristics over the last decade. Design: Retrospective review. Setting: A tertiary referral centre for joint replacement surgery in a teaching hospital in Hong Kong. Patients: All patients who underwent primary total knee arthroplasty for primary knee osteoarthritis from January 2000 to December 2009. Results: In all, 1157 total knee arthroplasties (589 left and 568 right) were performed on 588 females and 162 males. The annual number of total knee arthroplasties increased from 91 in 2000 to 181 in 2009. The annual number of patients increased from 58 (46 female, 12 male) in 2000 to 159 (117 female, 42 male) in 2009. When compared yearly results, there were no significant changes in the preoperative Knee Society Knee Score, Knee Society Functional Assessment, and passive range of motion of these patients. However, there was a significant decreasing trend with regard to lower limb mechanical axis mal-alignment, from 15.1° deviation from the neutral axis in 2000, to 14.8° deviation in 2004, and then 12.9° deviation in 2009 (mostly varus deformity). There was no difference between left knees and right knees, and between females and males. The mean age of the patients did not show significant change over the past decade, but the number and proportion of patients over 80 years old showed an increase from 4.8% (2000 to 2004) to 13.8% (2005 to 2009). On the other hand, the number and proportion of patients under the age of 60 years did not change. Conclusions: There was an increasing trend towards total knee arthroplasties, both in terms of number of operations and patients. The number of younger patients having total knee arthroplasty did not increase over the last 10 years, whereas the number of those older than 80 years increased significantly over that period.published_or_final_versio

Compression of micron-sized pillars of anodic aluminium oxide nano-honeycomb

Micro-pillars of anodic aluminium oxide with nano-sized honeycomb channels along the pillar axis exhibit compressive stressstrain response with large excursions corresponding to discrete, inhomogeneous deformation events. Each excursion is found to associate with the severe distortion of a material layer at the pillar's head, whereas the remaining of the pillar remains intact. The stresses at which these excursions occur do not exhibit any significant dependence on the pillar size. A simple model is proposed to describe the response of pillars under compression, which energetically, as well as kinetically, explains as to why the localized deformation always takes place at the pillar head. Predictions on the occurrence of instability events from this model also quantitatively agree with the experimental observations. © 2010 2010 Elsevier Ltd. All rights reserved.postprin

股骨旋轉的放射學評估：屍體標本研究

Purpose: To define how the lesser trochanter can be used in an objective manner to assess the femoral rotation in plain radiograph. Methods: Eighteen pairs of cadaveric femurs from Chinese individuals were used in this study. For each femur, radiographs were taken in the following positions with reference to the anatomical transepicondylar axis: neutral position; 5°, 10°, 15°, and 20° internal rotation; and 5°, 10°, 15°, and 20° external rotation. Lesser-trochanter index, which was defined as the width of lesser trochanter divided by the remaining width of the proximal femur, measured at the level of its most prominent point, which was perpendicular to the anatomical axis of the proximal femur, was obtained on a Picture Archiving Communication System workstation in every radiograph. Statistical analyses were performed by using a statistical software R (R language, version 2.12.0). Results: The lesser-trochanter index showed positive correlation with increasing external rotation of femur: correlation coefficient = 0.75 (p<0.00001). Analysis-of-variance test showed that the lesser-trochanter indexes of Group 1 (20° and 15° internal rotation), Group 2 (10° internal rotation to 10° external rotation), and Group 3 (15° and 20° external rotation) had statistically significant differences (p<0.00001). Receiver operating characteristic curves were used to determine the cutoff value of lesser-trochanter index to distinguish the three groups. By using the lower cutoff value as 0.17, we can distinguish Group 2 from Group 1 with a sensitivity of 0.85 and a specificity of 0.65. By using the upper cutoff value as 0.28, we can distinguish Group 2 from Group 3 with a sensitivity of 0.80 and a specificity of 0.73. Conclusion: The lesser-trochanter index can be used as a method to assess the rotational alignment of femur in plain radiograph. It is simple, objective, not affected by the factor of magnification, and can be applied to both long and short films. © 2012.link_to_subscribed_fulltex

On discovery of extremely low-dimensional clusters using semi-supervised projected clustering

Recent studies suggest that projected clusters with extremely low dimensionality exist in many real datasets. A number of projected clustering algorithms have been proposed in the past several years, but few can identify clusters with dimensionality lower than 10% of the total number of dimensions, which are commonly found in some real datasets such as gene expression profiles. In this paper we propose a new algorithm that can accurately identify projected clusters with relevant dimensions as few as 5% of the total number of dimensions. It makes use of a robust objective function that combines object clustering and dimension selection into a single optimization problem. The algorithm can also utilize domain knowledge in the form of labeled objects and labeled dimensions to improve its clustering accuracy. We believe this is the first semi-supervised projected clustering algorithm. Both theoretical analysis and experimental results show that by using a small amount of input knowledge, possibly covering only a portion of the underlying classes, the new algorithm can be further improved to accurately detect clusters with only 1% of the dimensions being relevant. The algorithm is also useful in getting a target set of clusters when there are multiple possible groupings of the objects. © 2005 IEEE.published_or_final_versio

Steady-state serrated deformation of metallic glass during indentation

Using an exponential load profile with a Berkovich tip, the strain bursts produced during nanoindentation of a (Cu55Mg33Y12)-Be bulk metallic glass are found to reach a steady state, in which the hardness becomes constant, the displacement jumps normalized by the indent depth approach a constant range 1.4 ± 1.2% and correspond to a reduction in hardness of 2.8 ± 2.4%, and the inter-burst duration multiplied by the strain rate approaches a constant range 1.8 ± 0.6%. This steady-state behavior is insensitive to the strain rate used. © 2009 Acta Materialia Inc.postprin

HARP: A practical projected clustering algorithm

In high-dimensional data, clusters can exist in subspaces that hide themselves from traditional clustering methods. A number of algorithms have been proposed to Identify such projected clusters, but most of them rely on some user parameters to guide the clustering process. The clustering accuracy can be seriously degraded If incorrect values are used. Unfortunately, in real situations, it is rarely possible for users to supply the parameter values accurately, which causes practical difficulties in applying these algorithms to real data. In this paper, we analyze the major challenges of projected clustering and suggest why these algorithms need to depend heavily on user parameters. Based on the analysis, we propose a new algorithm that exploits the clustering status to adjust the internal thresholds dynamically without the assistance of user parameters. According to the results of extensive experiments on real and synthetic data, the new method has excellent accuracy and usability. It outperformed the other algorithms even when correct parameter values were artificially supplied to them. The encouraging results suggest that projected clustering can be a practical tool for various kinds of real applications.published_or_final_versio

Women's sexuality after termination of pregnancy in Hong Kong Chinese

Objective: Our aim is to determine sexuality after termination of pregnancy (TOP) in Hong Kong Chinese. Design: This was a prospective study using self-administered questionnaires given before and eight weeks after abortion. Subjects: Women over age 18 years old requesting TOP were invited to participate in the study during the period 6 December 2005 to 28 March 2006. Main outcome measures: Sexual function, couple relationship and psychological well-being like depression and post-traumatic stress disorder (PTSD) were assessed. Contraception was also reviewed. Results: No significant change in the number of women who presented with sexual dysfunctions before and after abortion. However, women reported subjective decrease in sexual functions after TOP, ranging from 9.8% for those with increased vaginal pain to 24.5% for those with decreased sexual desire. Majority of them (74.8%) suffered from at least moderate degree of post-traumatic stress symptoms and 10.2% had symptoms suggestive of the presence of a PTSD. Significant associations were seen in subjective decrease of sexual functions with post-traumatic stress symptoms after termination of pregnancy. On the other hand, 41.6% felt less depressed after abortion. There was no significant change in couple relationship after abortion. Conclusion: Termination of pregnancy did not cause sexual dysfunctions. However, significant proportion of women did suffer from decreased sexual functions subjectively which may be due to stress related to unplanned pregnancy or the TOP. The abortion itself did not cause depression and women who had completed family were less depressed after abortion. Post-traumatic stress was prevalent in those having abortion and the symptoms were associated with the subjective decrease in sexual functions.published_or_final_versio

Identifying projected clusters from gene expression profiles

In microarray gene expression data, clusters may hide in subspaces. Traditional clustering algorithms that make use of similarity measurements in the full input space may fail to detect the clusters. In recent years a number of algorithms have been proposed to identify this kind of projected clusters, but many of them rely on some critical parameters whose proper values are hard for users to determine. In this paper a new algorithm that dynamically adjusts its internal thresholds is proposed. It has a low dependency on user parameters while allowing users to input some domain knowledge should they be available. Experimental results show that the algorithm is capable of identifying some interesting projected clusters from real microarray data.published_or_final_versio