2,242 research outputs found

    Response of Laser-Induced Thermal Lens Effect at Solid Surface

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    Recently Kuo et al. [1,2] and Satio et al.[3] presented the surface-thermal lens (STL) technique, this novel photothermal deformation technique has attracted great attention because it is a highly sensitive, noncontact and nondestructive measurement[4–6]. In this technique, a modulated pump beam is focused on the sample surface to produce the surface deformation and a cw probe beam is incident at the deformation region. Differing from the conventional photothermal deformation techniques, the spot size of the probe beam at the sample surface is much larger than the pump beam one. Then the probe beam reflected from the surface produces a diffraction pattern at the detection plane. More recently, STL technique has been successfully applied to study the temperature dependence of the thermal conductivity of semiconductor materials[5], weak absorption of optical thin films[6] and characterization of the solid materials[7,8]. However, the mechanism of STL phenomena has not been completely understood. Most theoretical models took no account of the influence of the air-thermal lens (ATL), although some experiment showed that the air significantly affected the detected diffraction pattern[2]. In addition, it is necessary to characterize frequency responses of signals because the response is used to determine the thermal property of the solid materials[5]

    Mini-open anterior spine surgery for anterior lumbar diseases

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    Minimally invasive surgeries including endoscopic surgery and mini-open surgery are current trend of spine surgery, and its main advantages are shorter recovery time and cosmetic benefits, etc. However, mini-open surgery is easier and less technique demanding than endoscopic surgery. Besides, anterior spinal fusion is better than posterior spinal fusion while considering the physiological loading, back muscle function, etc. Therefore, we aimed to introduce the modified “mini-open anterior spine surgery” (MOASS) and to evaluate the feasibility, effectiveness and safety in the treatment of various anterior lumbar diseases with this technique. A total of 61 consecutive patients (46 female, 15 male; mean age 58.2 years) from 1997 to 2004 were included in this study, with an average follow-up of 24–52 (mean 43) months. The disease entities included vertebral fracture (20), failed back surgery (13), segmental instability or spondylolisthesis (10), infection (8), herniated disc (5), undetermined lesion for biopsy (4), and hemivertebra (1). Lesions involved 13 cases at T12–L1, 18 at L1–L2, 18 at L2–L3, 22 at L3–L4 and 11 at L4–L5 levels. All patients received a single stage anterior-only procedure for their anterior lumbar disease. We used the subjective clinical results, Oswestry disability index, fusion rate, and complications to evaluate our clinical outcome. Most patients (91.8%) were subjectively satisfied with the surgery and had good-to-excellent outcomes. Mean operation time was 85 (62–124) minutes, and mean blood loss was 136 (minimal-250) ml in the past 6 years. Hospital stay ranged from 4–26 (mean 10.6) days. Nearly all cases had improved back pain (87%), physical function (90%) and life quality (85%). Most cases (95%) achieved solid or probable solid bony fusion. There were no major complications. Therefore, MOASS is feasible, effective and safe for patients with various anterior lumbar diseases

    ITPKC Single Nucleotide Polymorphism Associated with the Kawasaki Disease in a Taiwanese Population

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    Kawasaki disease (KD) is characterized by systemic vasculitis with unknown etiology. Previous studies from Japan indicated that a gene polymorphism of ITPKC (rs28493229) is responsible for susceptibility to KD. We collected DNA samples from 1,531 Taiwanese subjects (341 KD patients and 1,190 controls) for genotyping ITPKC. In this study, no significant association was noted for the ITPKC polymorphism (rs28493229) between the controls and KD patients, although the CC genotype was overrepresented. We further combined our data with previously published case/control KD studies in the Taiwanese population and performed a meta-analysis. A significant association between rs28493229 and KD was found (Odds Ratio:1.36, 95% Confidence Interval 1.12–1.66). Importantly, a significant association was obtained between rs28493229 and KD patients with aneurysm formation (P = 0.001, under the recessive model). Taken together, our results indicated that C-allele of ITPKC SNP rs28493229 is associated with the susceptibility and aneurysm formation in KD patients in a Taiwanese population

    Intermittent control models of human standing: similarities and differences

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    Two architectures of intermittent control are compared and contrasted in the context of the single inverted pendulum model often used for describing standing in humans. The architectures are similar insofar as they use periods of open-loop control punctuated by switching events when crossing a switching surface to keep the system state trajectories close to trajectories leading to equilibrium. The architectures differ in two significant ways. Firstly, in one case, the open-loop control trajectory is generated by a system-matched hold, and in the other case, the open-loop control signal is zero. Secondly, prediction is used in one case but not the other. The former difference is examined in this paper. The zero control alternative leads to periodic oscillations associated with limit cycles; whereas the system-matched control alternative gives trajectories (including homoclinic orbits) which contain the equilibrium point and do not have oscillatory behaviour. Despite this difference in behaviour, it is further shown that behaviour can appear similar when either the system is perturbed by additive noise or the system-matched trajectory generation is perturbed. The purpose of the research is to come to a common approach for understanding the theoretical properties of the two alternatives with the twin aims of choosing which provides the best explanation of current experimental data (which may not, by itself, distinguish beween the two alternatives) and suggesting future experiments to distinguish between the two alternatives

    Augmented TLR2 Expression on Monocytes in both Human Kawasaki Disease and a Mouse Model of Coronary Arteritis

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    BACKGROUND: Kawasaki disease (KD) of unknown immunopathogenesis is an acute febrile systemic vasculitis and the leading cause of acquired heart diseases in childhood. To search for a better strategy for the prevention and treatment of KD, this study compared and validated human KD immunopathogenesis in a mouse model of Lactobacillus casei cell wall extract (LCWE)-induced coronary arteritis. METHODS: Recruited subjects fulfilled the criteria of KD and were admitted for intravenous gamma globulin (IVIG) treatment at the Kaohsiung Chang Gung Memorial Hospital from 2001 to 2009. Blood samples from KD patients were collected before and after IVIG treatment, and cardiovascular abnormalities were examined by transthoracic echocardiography. Wild-type male BALB/c mice (4-week-old) were intraperitoneally injected with LCWE (1 mg/mL) to induce coronary arteritis. The induced immune response in mice was examined on days 1, 3, 7, and 14 post injections, and histopathology studies were performed on days 7 and 14. RESULTS: Both human KD patients and LCWE-treated mice developed coronary arteritis, myocarditis, valvulitis, and pericarditis, as well as elevated plasma levels of interleukin (IL)-2, IL-6, IL-10, monocyte chemoattractant protein (MCP)-1, and tumor necrosis factor (TNF)-α in acute phase. Most of these proinflammatory cytokines declined to normal levels in mice, whereas normal levels were achieved in patients only after IVIG treatment, with a few exceptions. Toll-like receptor (TLR)-2, but not TLR4 surface enhancement on circulating CD14+ monocytes, was augmented in KD patients before IVIG treatment and in LCWE-treated mice, which declined in patients after IVIG treatment. CONCLUSION: This result suggests that that not only TLR2 augmentation on CD14+ monocytes might be an inflammatory marker for both human KD patients and LCWE-induced CAL mouse model but also this model is feasible for studying therapeutic strategies of coronary arteritis in human KD by modulating TLR2-mediated immune activation on CD14+ monocytes

    Regulation of p14ARF expression by miR-24: a potential mechanism compromising the p53 response during retinoblastoma development

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    <p>Abstract</p> <p>Background</p> <p>Most human cancers show inactivation of both pRB- and p53-pathways. While retinoblastomas are initiated by loss of the <it>RB1 </it>tumor suppressor gene, <it>TP53 </it>mutations have not been found. High expression of the p53-antagonist MDM2 in human retinoblastomas may compromise p53 tumor surveillance so that <it>TP53 </it>mutations are not selected for in retinoblastoma tumorigenesis. We previously showed that p14<sup>ARF </sup>protein, which activates p53 by inhibiting MDM2, is low in retinoblastomas despite high mRNA expression.</p> <p>Methods</p> <p>In human fetal retinas, adult retinas, and retinoblastoma cells, we determined endogenous <it>p14<sup>ARF </sup></it>mRNA, ARF protein, and miR-24 expression, while integrity of p53 signalling in WERI-Rb1 cells was tested using an adenovirus vector expressing p14<sup>ARF</sup>. To study p14<sup>ARF </sup>biogenesis, retinoblastoma cells were treated with the proteasome inhibitor, MG132, and siRNA against miR-24.</p> <p>Results</p> <p>In human retinoblastoma cell lines, <it>p14<sup>ARF </sup></it>mRNA was disproportionally high relative to the level of p14<sup>ARF </sup>protein expression, suggesting a perturbation of p14<sup>ARF </sup>regulation. When p14<sup>ARF </sup>was over-expressed by an adenovirus vector, expression of p53 and downstream targets increased and cell growth was inhibited indicating an intact p14<sup>ARF</sup>-p53 axis. To investigate the discrepancy between <it>p14<sup>ARF </sup></it>mRNA and protein in retinoblastoma, we examined p14<sup>ARF </sup>biogenesis. The proteasome inhibitor, MG132, did not cause p14<sup>ARF </sup>accumulation, although p14<sup>ARF </sup>normally is degraded by proteasomes. miR-24, a microRNA that represses p14<sup>ARF </sup>expression, is expressed in retinoblastoma cell lines and correlates with lower protein expression when compared to other cell lines with high <it>p14<sup>ARF </sup></it>mRNA. Transient over-expression of siRNA against miR-24 led to elevated p14<sup>ARF </sup>protein in retinoblastoma cells.</p> <p>Conclusions</p> <p>In retinoblastoma cells where high levels of <it>p14<sup>ARF </sup></it>mRNA are not accompanied by high p14<sup>ARF </sup>protein, we found a correlation between miR-24 expression and low p14<sup>ARF </sup>protein. p14<sup>ARF </sup>protein levels were restored without change in mRNA abundance upon miR-24 inhibition suggesting that miR-24 could functionally repress expression, effectively blocking p53 tumor surveillance. During retinal tumorigenesis, miR-24 may intrinsically compromise the p53 response to <it>RB1 </it>loss.</p

    An outcome analysis of self-expandable metallic stents in central airway obstruction: a cohort study

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    <p>Abstract</p> <p>Background</p> <p>Self-expandable metallic stents (SEMSs) have provided satisfactory management of central airway obstruction. However, the long-term benefits and complications of this management modality in patients with benign and malignant obstructing lesions after SEMS placement are unclear. We performed this cohort study to analyze the outcomes of Ultraflex SEMSs in patients with tracheobronchial diseases.</p> <p>Methods</p> <p>Of 149 patients, 72 with benign and 77 with malignant tracheobronchial disease received 211 SEMSs (benign, 116; malignant, 95) and were retrospectively reviewed in a tertiary hospital.</p> <p>Results</p> <p>The baseline characteristics of patients who received SEMS implantation for benign conditions and those who underwent implantation for malignant conditions were significantly different. These characteristics included age (mean, 63.9 vs. 58; <it>p </it>< 0.01), gender (male, 62% vs. 90%; <it>p </it>< 0.0001), smoking (47% vs. 85%; <it>p </it>< 0.0001), forced expiratory volume in 1 second (mean, 0.9 vs. 1.47 L/s; <it>p </it>< 0.0001), follow-up days after SEMS implantation (median; 429 vs. 57; <it>p </it>< 0.0001), and use of covered SEMS (36.2% vs. 94.7%; <it>p </it>< 0.0001). Symptoms improved more after SEMS implantation in patients with benign conditions than in those with malignant conditions (76.7% vs. 51.6%; <it>p </it>< 0.0001). The overall complication rate after SEMS implantation in patients with benign conditions was higher than that in patients with malignancy (42.2% vs. 21.1%; <it>p </it>= 0.001). Successful management of SEMS migration, granulation tissue formation, and SEMS fracture occurred in 100%, 81.25%, and 85% of patients, respectively.</p> <p>Conclusions</p> <p>Patients who received SEMS implantation owing to benign conditions had worse lung function and were older than those who received SEMS for malignancies. There was higher complication rate in patients with benign conditions after a longer follow-up period owing to the nature of the underlying diseases.</p

    Perceptions of Pakistani medical students about drugs and alcohol: a questionnaire-based survey

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    BACKGROUND: Drug abuse is hazardous and known to be prevalent among young adults, warranting efforts to increase awareness about harmful effects and to change attitudes. This study was conducted to assess the perceptions of a group of medical students from Pakistan, a predominantly Muslim country, regarding four drugs namely heroin, charas, benzodiazepines and alcohol. RESULTS: In total, 174 self-reported questionnaires were received (87% response rate). The most commonly cited reasons for why some students take these drugs were peer pressure (96%), academic stress (90%) and curiosity (88%). The most commonly cited justifiable reason was to go to sleep (34%). According to 77%, living in the college male hostel predisposed one to using these drugs. Sixty percent of students said that the drugs did not improve exam performance, while 54% said they alleviated stress. Seventy-eight percent said they did not intend to ever take drugs in the future. Females and day-scholars were more willing to discourage a friend who took drugs. Morality (78%), religion (76%) and harmful effects of drugs (57%) were the most common deterrents against drug intake. Five suggestions to decrease drug abuse included better counseling facilities (78%) and more recreational facilities (60%). CONCLUSION: Efforts need to be made to increase student awareness regarding effects and side effects of drugs. Our findings suggest that educating students about the adverse effects as well as the moral and religious implications of drug abuse is more likely to have a positive impact than increased policing. Proper student-counseling facilities and healthier avenues for recreation are also required

    S100A6 (Calcyclin) is a prostate basal cell marker absent in prostate cancer and its precursors

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    S100A6 (Calcyclin) is a calcium-binding protein that has been implicated in a variety of biological functions as well as tumorigenesis. The aim of our study was to investigate the involvement of S100A6 during prostate cancer development and progression. Using immunohistochemistry, the expression of S100A6 was examined in benign (n ÂŒ 66), premalignant (n ÂŒ 10), malignant (n ÂŒ 66) and metastatic prostate (n ÂŒ 5) tissues arranged in a tissue-microarray or whole sections as well as in prostate cancer cell lines. The S100A6 immunostaining pattern in tissues was compared with that of cytokeratin 5 (a basal cell marker) and 18 (a benign luminal cell marker). In all cases of benign epithelium, intense S100A6 expression was seen in the basal cell layer with absent staining in luminal cells. In all cases of prostatic adenocarcinoma (matched), metastatic lesions and 3/10 high-grade prostatic intraepithelial neoplasia lesions, an absence of S100A6 was seen. Western blotting and RT–PCR analysis of cell lines showed S100A6 expression to be absent in LNCaP, LNCaP-LN3 and LNCaP-Pro5 but present in Du145, PC3, PC-3M and PC-3M-LN4. LNCaP cells treated with 5- Azacytidine, caused re-expression of S100A6 mRNA. Sequencing of bisulphite modified DNA showed CpG methylation within the S100A6 promoter region and exon 1 of LNCaP, LNCaP-LN3 and LNCaP-Pro5 cell lines but not in Du145 cells. Our data suggest that loss of S100A6 protein expression is common in prostate cancer development and may occur at an early stage. The mechanism of loss of expression may involve hypermethylation of CpG sites. The finding of intense S100A6 expression in the basal cells of benign glands but loss of expression in cancer could be useful as a novel diagnostic marker for prostate cancer

    Clusters of galaxies : observational properties of the diffuse radio emission

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    Clusters of galaxies, as the largest virialized systems in the Universe, are ideal laboratories to study the formation and evolution of cosmic structures...(abridged)... Most of the detailed knowledge of galaxy clusters has been obtained in recent years from the study of ICM through X-ray Astronomy. At the same time, radio observations have proved that the ICM is mixed with non-thermal components, i.e. highly relativistic particles and large-scale magnetic fields, detected through their synchrotron emission. The knowledge of the properties of these non-thermal ICM components has increased significantly, owing to sensitive radio images and to the development of theoretical models. Diffuse synchrotron radio emission in the central and peripheral cluster regions has been found in many clusters. Moreover large-scale magnetic fields appear to be present in all galaxy clusters, as derived from Rotation Measure (RM) studies. Non-thermal components are linked to the cluster X-ray properties, and to the cluster evolutionary stage, and are crucial for a comprehensive physical description of the intracluster medium. They play an important role in the cluster formation and evolution. We review here the observational properties of diffuse non-thermal sources detected in galaxy clusters: halos, relics and mini-halos. We discuss their classification and properties. We report published results up to date and obtain and discuss statistical properties. We present the properties of large-scale magnetic fields in clusters and in even larger structures: filaments connecting galaxy clusters. We summarize the current models of the origin of these cluster components, and outline the improvements that are expected in this area from future developments thanks to the new generation of radio telescopes.Comment: Accepted for the publication in The Astronomy and Astrophysics Review. 58 pages, 26 figure
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