Self-compensation method for dual-beam roll angle measurement of linear stages.

In this paper, a self-compensation method for improving the accuracy of roll angle measurement of a linear stage caused by the non-parallelism of dual-beam due to time-dependent mechanical deformation of the support is proposed and integrated into a 5-DOF sensor to verify the feasibility. The non-parallelism between two laser beams is online real-time monitored by a pair of small autocollimator units. Through the ray-tracing analysis, the method to separate the roll angle of the moving stage and non-parallelism induced roll error is determined. A series of experiments under different supporting forces and ambient conditions have been carried out. The compensated P-V values of the roll angles are all within ±4 arc-sec, no matter how bad the originally measured value of the linear stage is. The average improvement of about 95% is significant. The effectiveness and robustness of the proposed measurement system in the changing environment are verified.

Laser-based precision alignment for multiple span rotary shafts.

By converting the alignment issue of multiple span rotary shafts into a non-connected shaftalignment issue, we present a precision alignment strategy for multiple span shafts, and a laser-based method for measuring misalignment of non-connected shafts is proposed. The quadrant photodiode detector was calibrated at different rotation angles to obtain the sensitivity coefficient. According to the calibration results, the experiment scheme of the method was optimized. Then measurement experiments were carried out and the error source, the measurement uncertainty of the results were analyzed. Finally, the misalignment was also measured by a coordinate measuring machine, and the comparison results show that the relative error of the two methods is less than 5%. Therefore, the proposed method can be applied to align multiple span shafts accurately. Furthermore, this method can also be used for non-connected shaft position determinations such as wheel alignment inspections, alignment of machine spindle and center shaft, and others.

A five degrees-of-freedom errors measurement system for rotary axis with reference laser for reference axis alignment.

This paper proposes a five degrees-of-freedom measurement system for measuring geometric errors of the rotary axis. To align the measured rotary axis with the reference axis, a diode laser is used to represent the rotary axis of the measured rotation stage. Based on the proposed measurement system, a model for separating the position independent geometric errors and position dependent geometric errors of the measured rotary axis from the measured value is established and verified by measurement experiments. The results of measurement experiments repeated for five times show that the measurement uncertainty of the proposed measurement system is less than ±1.6 µm for radial motion, the measurement uncertainty is less than ±1.7 arc sec for tilt motion, and the measurement uncertainty is less than ±1.3 arc sec for angle position.

Error Analysis and Compensation of a Laser Measurement System for Simultaneously Measuring Five-Degree-of-Freedom Error Motions of Linear Stages.

A robust laser measurement system (LMS), consisting of a sensor head and a detecting part, for simultaneously measuring five-degree-of-freedom (five-DOF) error motions of linear stages, is proposed and characterized. For the purpose of long-travel measurement, all possible error sources that would affect the measurement accuracy are considered. This LMS not only integrates the merits of error compensations for the laser beam drift, beam spot variation, detector sensitivity variation, and non-parallelism of dual-beam that have been resolved by the author's group before, but also eliminates the crosstalk errors among five-DOF error motions in this study. The feasibility and effectiveness of the designed LMS and modified measurement model are experimentally verified using a laboratory-built prototype. The experimental results show that the designed LSM has the capability of simultaneously measuring the five-DOF error motions of a linear stage up to one-meter travel with a linear error accuracy in sub-micrometer and an angular error accuracy in sub-arcsecond after compensation.

An Embedded Sensor System for Real-Time Detecting 5-DOF Error Motions of Rotary Stages.

The geometric error motions of rotary stages greatly affect the accuracy of constructed machines such as machine tools, measuring instruments, and robots. In this paper, an embedded sensor system for real-time measurement of two radial and three angular error motions of a rotary stage is proposed, which makes use of a rotary encoder with multiple scanning heads to measure the rotational angle and two radial error motions and a miniature autocollimator to measure two tilt angular errors of the axis of rotation. The assembly errors of the grid disc of the encoder and the mirror for autocollimator are also evaluated and compensated. The developed measuring device can be fixed inside the rotary stage. In the experiments, radial error motions of two points on the axis (h = 5 mm and 60 mm) were measured and calibrated with LVDTs, and the data showed that the radial error motions of the axis were less than 20 µm, and the calibration residual errors were less than 2 µm. When intermittent external forces were applied to the stage, the change of the stage's error motion could also be monitored accurately.

Detection of Significant Pneumococcal Meningitis Biomarkers by Ego Network.

OBJECTIVE: To identify significant biomarkers for detection of pneumococcal meningitis based on ego network. METHODS: Based on the gene expression data of pneumococcal meningitis and global protein-protein interactions (PPIs) data recruited from open access databases, the authors constructed a differential co-expression network (DCN) to identify pneumococcal meningitis biomarkers in a network view. Here EgoNet algorithm was employed to screen the significant ego networks that could accurately distinguish pneumococcal meningitis from healthy controls, by sequentially seeking ego genes, searching candidate ego networks, refinement of candidate ego networks and significance analysis to identify ego networks. Finally, the functional inference of the ego networks was performed to identify significant pathways for pneumococcal meningitis. RESULTS: By differential co-expression analysis, the authors constructed the DCN that covered 1809 genes and 3689 interactions. From the DCN, a total of 90 ego genes were identified. Starting from these ego genes, three significant ego networks (Module 19, Module 70 and Module 71) that could predict clinical outcomes for pneumococcal meningitis were identified by EgoNet algorithm, and the corresponding ego genes were GMNN, MAD2L1 and TPX2, respectively. Pathway analysis showed that these three ego networks were related to CDT1 association with the CDC6:ORC:origin complex, inactivation of APC/C via direct inhibition of the APC/C complex pathway, and DNA strand elongation, respectively. CONCLUSIONS: The authors successfully screened three significant ego modules which could accurately predict the clinical outcomes for pneumococcal meningitis and might play important roles in host response to pathogen infection in pneumococcal meningitis.

Replacement of severely traumatized teeth with immediate implants and immediate loading: literature review and case reports.

One of the options for management of severely traumatized dentitions is to provide immediate implant placement with immediate loading. Three representative cases out of 15 patients with 23 traumatized teeth treated to date in our clinic are presented. None had labial bone fractures. The teeth were replaced with NobelReplace Groovy implants (Nobel Biocare, Gothenburg, Sweden) in the fresh sockets immediately after extraction. They were placed toward the palatal areas in the sockets and 3 mm below the gingival margins. If there were gaps between implants and sockets wider than 1 mm, particulate deproteinized bovine bone was grafted in the gaps. Immediately after placement, the implants were loaded with provisional prostheses. The final restorations were installed 3-4 months later. The patients were reevaluated clinically and radiographically 1-3 years after the final restorations had been placed. In all 15 patients, excellent functional and esthetic results were achieved. No implants showed radiolucency, peri-implant suppuration, or mobility. The patients were satisfied with the results. Immediate implant placement with immediate loading is an option that provides good treatment outcomes and allows good functional and esthetic results, as well as addressing the social/psychological aspects of dental trauma.

Alcohol consumption and the neoplastic progression in Barrett's esophagus: a systematic review and meta-analysis.

PURPOSE: In the developed countries, the incidence of esophageal adenocarcinoma (EAC) is increasing over recent decades. The purpose of this meta-analysis was to arrive at quantitative conclusions about the contribution of alcohol intakes and the progression of Barrett's esophagus. METHODS: A comprehensive, systematic bibliographic search of medical literature published up to Oct 2013 was conducted to identify relevant studies. A meta-analysis was conducted for alcohol consumption on the Barrett's esophagus progression. RESULTS: A total of 882 cases in 6,867 individuals from 14 observational studies were indemnified in this meta-analysis. The result of this current meta-analysis, including 10 case-control and 4 cohort studies, indicated that alcohol consumption was not associated with the neoplastic progression in Barrett's esophagus (RR, 1.17; 95% CI, 0.93-1.48). When stratified by the study designs, no significant association was detected in either high vs low group or ever vs never group. CONCLUSIONS: Alcohol drinking is not associated with risk of neoplastic progression in Barrett's esophagus. Further well designed studies are needed in this area.

E3 ubiquitin ligases and human papillomavirus-induced carcinogenesis.

Human papillomavirus (HPV) infection is clinically very common. It is usually a major risk factor in the development of cutaneous benign lesions, cervical cancer and a variety of other malignancies. The biological function of ubiquitination as an intracellular proteasomal-mediated form of protein degradation and an important modulator in the regulation of many fundamental cellular processes has been increasingly recognized over the last decade. HPV proteins have been demonstrated to evolve different strategies to utilize the ubiquitin system for their own purposes. The putative roles of E3 ubiquitin ligases in HPV-induced carcinogenesis have become increasingly apparent, although the mechanisms remain unclear. In this review we provide an update on the mechanisms of the involvement of E3 ubiquitin ligases in HPV-induced carcinogenesis, focusing on their interaction with HPV proteins and their roles in several signalling pathways. Targeting the E3 ubiquitin ligases might offer potential therapeutic strategies for HPV-related diseases in future.