The robust UCATR algorithm enhances the specificity and sensitivity to detect the infarct of acute ischaemic stroke within 6 hours of onset via non-contrast computed tomography images.

PROBLEM BACKGROUND: Early detection of acute ischemic stroke (AIS) may provide patients with benefits against harmful health and financial impacts. The use of non-contrast computed tomography images for early detect of the infarct remains controversial. MATERIALS & METHODS: Here, we used the UCATR algorithm to extract the pixel values of the infarct and the corresponding contralateral healthy area as the control surface in each NCCT slice for the whole brain. Magnetic resonance imaging results were used to verify both areas. We found significant pathological changes in the infarct compared with the corresponding contralateral healthy area in each NCCT slice. ATTAINED RESULTS: Our approach validated that NCCT can be used to detect the lesion area in the early stage of AIS. CONCLUSIONS: With obvious advantages such as saving time and the ability to quantify the infarct volume, this approach could help more patients survive the fatal and irreversible pathological process of AIS and improve their quality of life after AIS treatment.

High-accuracy and high-repeatability measurement of the cut error of a nonlinear uniaxial crystal.

To accurately determine the optical axis cut error of a nonlinear uniaxial crystal, a measurement method based on dual-optical path second-harmonic energy (SHE) rocking curve acquisition is presented in, of which the measurement uncertainty can be controlled within 3.20 µrad , 26 times higher than that of a high-precision commercial x-ray diffractometer (XRD). To meet the measurement requirements, a Type I potassium dihydrogen phosphate reference crystal (RC) is first made, and its optical axis cut error is considered as a reference. Then, the optical axis cut error of a measured crystal (MC) with an aperture of 25mm×25mm and a thickness of 10 mm is determined by simultaneously recording the SHE scatter plots of the RC and the MC, where the measurement repeatability of 10 consecutive measurements is only 4.48 µrad and the measurement speed is within 20 s. During data processing, a third-order Fourier polynomial is proposed to fit the scatter plots into smooth curves, of which the regression coefficients are greater than 0.9975. The experimental method not only overcomes the shortcomings that XRDs will introduce scratches and defects to the crystal surface and are unable to measure large-aperture crystals, but can be used to guide the production of precise cutting of a nonlinear uniaxial crystal, thus ensuring the maximum conversion efficiency of a frequency multiplication system.

A simple high-precision wide-spectrum interferometric system.

This paper presents a simple system capable of detecting wavefront information in the wavelength range of 488-1064 nm based on an interferometric system consisting of a ball lens and an aspheric collimator. The design is conducive to short-distance Gaussian beam expansion and collimation at multiple wavelengths. The design principles and performance of the system are described in detail; the measurement precision of the system is verified experimentally by measuring the surface profile of a piece of uncoated N-BK7 glass at various test wavelengths with the proposed setup and with a digital 4D FizCam 2000 interferometer. The highly consistent measurement results of the two methods reveal that the proposed system operates precisely and effectively at various wavelengths. Subsequently, the system is applied to measure the transmitted-wavefront error of a solar filter at a wavelength of 808.0 nm; the measurement results show superb repeatability. The proposed technique avoids the shortcomings of conventional single-working-wavelength interferometric systems, which can neither work in a wide spectrum with high precision nor measure the wavefront properties of many optical bandpass elements in one device; this technique also provides technical support for future applications of high-precision and low-cost wavelength-switchable laser interferometers.

Apparatus for measuring the uniformity of the optical transmittance of a semispherical surface at normal incidence.

In this paper, we build an apparatus for measuring the optical transmittance and its uniformity for a semispherical surface at normal incidence; the system is primarily comprised of a traditional double-beam photometric framework and a novel custom-made mechanical structure with multidimensional degrees of freedom. During the measurement process, a key aligning step is adopted to guarantee that the center point of the semispherical surface stands still in the light beam while scanning the hemispherical optical element point by point around the horizontal and vertical axes, which ensures that the laser beam is always normally incident onto the surface of the hemisphere. The experimental results show that the uniformity of the optical transmittance for a semispherical optical glass can be successfully characterized by the system, with a three-cycle repeatability error of 0.026% being demonstrated. Our system solves the problem of traditional spectrophotometers when measuring the spectral property of a hemispherical surface and thus can be popularized in similar applications.

[Clinical therapeutic effect of point-injection combined with body acupuncture on prementstrual tension syndrome].

OBJECTIVE: To compare clinical therapeutic effects of acupoint-injection combined with body acupuncture and medication on premenstrual tension syndrome, and probe to the best therapy for this disease. METHODS: One hundred and two cases were randomly divided into an acupoint-injection plus body acupuncture group (treatment group) and a medication group (control group). The treatment group were treated with injection of Huangqi Injection into Zusanli (ST 36), Sanyinjiao (SP 6), and acupuncture at Hegu (LI 4), Taichong (LR 3), Guanyuan (CV 4), Qihai (CV 6), Taiyang (EX-HN5), Fengchi (GB 20) 10 days before menstruation, once every three days; the control group were treated by oral administration of diazepam and oryzanol at routine dose 10 days before menstruation until stopping of menstrual. Their therapeutic effects were compared after treatment for 3 menstrual cycles. RESULTS: The total effective rate was 92.6% in the treatment group and 75.0% in the control group with a significant difference between the two groups (P<0.05). CONCLUSION: The clinical therapeutic effect of the acupoint-injection combined with body acupuncture is better than that of the medication on premenstrual tension syndrome.