Portable 5-DOF measurement system using a parallel beam generation method for linear axis detection.

Geometric error detection is crucial for evaluating the accuracy of the linear axis. However, the practicality of traditional dual-beam detection systems is limited by the parallelism of beams. This study proposes a portable 5-DOF measurement system using a novel parallel beam generation method.

Directional region-based feature point matching algorithm based on SURF.

Feature point matching is one of the fundamental tasks in binocular vision. It directly affects the accuracy and quality of 3D reconstruction. This study proposes a directional region-based feature point matching algorithm based on the SURF algorithm to improve the accuracy of feature point matching.

A novel uncertainty evaluation method based on the particle filter and beta distribution for data with unknown distribution.

Uncertainty evaluation for unknown distribution data is a key problem to be solved in uncertainty evaluation theory. To evaluate the measurement uncertainty of data with unknown distributions, a novel uncertainty evaluation method based on the particle filter (PF) and beta distribution is proposed in this paper. A beta distribution with wide adaptability was adopted as the distribution type of measurement results, the parameters of the beta distribution were taken as the parameters to be estimated, and a state-space model was established.

High-Precision Fabrication of Micro Monolithic Tungsten Ball Tips via Arc Discharge and the Taguchi Method.

A micro ball tip is a core component of high precision coordinate measuring machines. The present micro ball tips cannot satisfy the high-precision measuring requirements of high aspect ratio microstructures due to their large diameter and low accuracy. In the previous study, we fabricated a micro monolithic tungsten ball tip by using arc discharge and surface tension principles.

Drift Reduction of a 4-DOF Measurement System Caused by Unstable Air Refractive Index.

Laser beam drift greatly influences the accuracy of a four degrees of freedom (4-DOF) measurement system during the detection of machine tool errors, especially for long-distance measurement. A novel method was proposed using bellows to serve as a laser beam shield and air pumps to stabilize the refractive index of air. The inner diameter of the bellows and the control mode of the pumps were optimized through theoretical analysis and simulation.

Modeling and Optimal Design for a High Stability 2D Optoelectronic Angle Sensor.

The structural deformations caused by environmental changes in temperature, vibration, and other factors are harmful to the stability of high precision measurement equipment. The stability and optimal design method of a 2D optoelectronic angle sensor have been investigated in this study. The drift caused by structural deformations of the angle sensor has been studied and a drift error model has been achieved.

A Scanning Probe Microscope for Surface Measurement in Nano-Scale.

A tapping mode scanning probe microscopy (TM SPM) system for surface measurement in nanoscale is developed, of which the main element is a scanning probe consisting of quartz tuning fork and a long sharp tungsten tip. Quartz tuning fork is a very good resonant element with piezoelectrical characteristic, and it acts as an actuator and a force sensor simultaneously in the probe. The vertical spatial resolution of the TM SPM is up to sub-nanometer (0.

GABAAα1 and GABAAρ1 subunits are expressed in cultured human RPE cells and GABAA receptor agents modify the intracellular calcium concentration.

Purpose: Gamma-aminobutyric acid A (GABAA) receptors (GABAARs), which are ionotropic receptors involving chloride channels, have been identified in various neural (e.g., mouse retinal ganglion cells) and nonneural cells (e.

GABAB receptor antagonist CGP46381 inhibits form-deprivation myopia development in guinea pigs.

The aim was to investigate the effects of the GABAB receptor antagonist, CGP46381, on form-deprivation myopia (FDM) in guinea pigs. Twenty-four guinea pigs had monocular visual deprivation induced using a diffuser for 11 days (day 14 to 25). The deprived eyes were treated with daily subconjunctival injections (100 μl) of either 2% CGP46381, 0.

Inhibition of form-deprivation myopia by a GABAAOr receptor antagonist, (1,2,5,6-tetrahydropyridin-4-yl) methylphosphinic acid (TPMPA), in guinea pigs.

Purpose: To investigate the effects of the relatively selective GABAAOr receptor antagonist (1,2,5,6-tetrahydropyridin-4-yl) methylphosphinic acid (TPMPA) on form-deprivation myopia (FDM) in guinea pigs.

Methods: A diffuser was applied monocularly to 30 guinea pigs from day 10 to 21. The animals were randomized to one of five treatment groups.

GABAB receptors expressed in human aortic endothelial cells mediate intracellular calcium concentration regulation and endothelial nitric oxide synthase translocation.

GABAB receptors regulate the intracellular Ca2+ concentration ([Ca2+]i) in a number of cells (e.g., retina, airway epithelium and smooth muscle), but whether they are expressed in vascular endothelial cells and similarly regulate the [Ca2+]i is not known.

GABAB receptors are expressed in human aortic smooth muscle cells and regulate the intracellular Ca(2+) concentration.

The aim of this study was to investigate the expression of GABAB receptors, a subclass of receptors to the inhibitory neurotransmitter gamma-aminobutyric acid (GABAB), in human aortic smooth muscle cells (HASMCs), and to explore if altering receptor activation modified intracellular Ca(2+) concentration ([Ca(2+)]i) of HASMCs. Real-time PCR, western blots and immunofluorescence were used to determine the expression of GABABR1 and GABABR2 in cultured HASMCs. Immunohistochemistry was used to localize the two subunits in human left anterior descending artery (LAD).

Identification of GABA receptors in chick retinal pigment epithelium.

Purpose: The retinal pigment epithelium (RPE) is a multifunctional, monolayer of cells located between the neural retina and the choroicapillaris. γ-Aminobutyric acid (GABA) is the most important inhibitory neurotransmitter in the retina and GABA receptors are known to be present in chick retina, sclera and cornea. There is a report of genes involved in GABA receptor signaling being expressed in human RPE, however, whether GABA receptors are present in chick RPE is unknown.

Identification of GABA receptors in chick cornea.

Purpose: The cornea has an important role in vision, is highly innervated and many neurotransmitter receptors are present, e.g., muscarine, melatonin, and dopamine receptors.

ρ1 GABAC receptors are expressed in fibrous and cartilaginous layers of chick sclera and located on sclera fibroblasts and chondrocytes.

rho(1) GABA(C) receptor antagonists inhibit myopia in chick but the site of this effect is not known. The sclera ultimately determines the shape and size of the globe and thus an untested possibility is that GABA agents have a scleral mechanism. Whether rho(1) GABA(C) receptors are expressed and located in chick sclera is unknown.

Seven-year follow-up of LASIK for moderate to severe myopia.

Purpose: To evaluate long-term refractive outcomes of LASIK for correcting moderate to severe myopia.

Methods: A long-term (7-year) prospective follow-up study of visual and refractive outcomes in patients who underwent myopic LASIK surgery in 1998 and 1999. Fifty-nine patients (104 eyes) of the original cohort of 75 patients underwent detailed clinical assessment at 1 and 7 years postoperatively.

Long-term prospective follow-up study of myopic photorefractive keratectomy.

The aim of this study was to evaluate the long-term outcome of excimer laser myopic photorefractive keratectomy (PRK). We undertook an 11-year prospective follow-up study of visual and refractive outcomes in 46 patients (85 eyes). The main outcome measures were predictability, efficacy, stability and safety of PRK.

Effect of flap thickness on higher order wavefront aberrations induced by LASIK: a bilateral study.

Purpose: To investigate the effect of flap thickness on wavefront aberrations induced by LASIK.

Methods: LASIK was performed on 56 eyes of 28 patients with refraction errors that were well matched between the right and left eyes. For each patient, a planned 160-microm flap was created for one randomly selected eye using the Moria M2 microkeratome (130-microm head; thick flap group), and a 110-microm flap was created for the contralateral eye with the same microkeratome (90-microm head; thin flap group).

[Influence of diameter of optical zone ablation on LASIK-induced higher order optical aberrations in myopia].

Objective: To analyze the effects of optical zone ablation diameter on LASIK-induced higher order optical aberrations in myopia.

Methods: Four hundred and sixty-one eyes of 236 patients treated with LASIK for myopia were divided into high, moderate and low myopia group according to preoperative spherical equivalent diopter. In each group, eyes were divided into four subgroups according to optic zone ablation diameter.

[Effects of flashing light on ocular growth and development of myopia in pigmented guinea pigs].

Objective: To investigate the effects of flashing light exposure on ocular growth and development of myopia in guinea pigs.

Methods: Thirty 4-week-old pigmented guinea pigs were randomly divided into three groups. Animals in group I were reared with the flashing light continuously and lasted for 6 weeks.

[Effect of time limited form deprivation on the development of myopia in guinea pigs].

Objective: To investigate the effect of time limited form deprivation on the development of form-deprived-myopia (FDM) in guinea pigs.

Methods: Four-week-old guinea pigs (n = 20) were randomly divided into four groups. Group I was used as normal control without any treatment.