Two novel ultrasound imaging techniques with imaging contrast mechanisms are in the works: X-ray-induced acoustic computed tomography (XACT), and nanoscale photoacoustic tomography (nPAT). XACT has incredible potential in: (1) biomedical imaging, through which a 3D image can be generated using only a single X-ray projection, and (2) radiation dosimetry. nPAT as a new alternative of super-resolution microscopy can break through the optical diffraction limit and is capable of exploring sub-cellular structures without reliance on fluorescence labeling. We expect these new imaging techniques to find widespread applications in both pre-clinical and clinical biomedical research.

The aim of this study is to examine the small-world properties of functional brain networks in Chinese to English simultaneous interpreting (SI) using functional near-infrared spectroscopy (fNIRS). In particular, the fNIRS neuroimaging combined with complex network analysis was performed to extract the features of functional brain networks underling three translation strategies associated with Chinese to English SI: “transcoding" that takes the “shortcut" linking translation equivalents between Chinese and the English, “code-mixing" that basically does not involve bilingual processing, and “transphrasing" that takes the “long route" involving a monolingual processing of meaning in Chinese and then another monolingual processing of meaning in English. Our results demonstrated that the small-world network topology was able to distinguish well between the transcoding, code-mixing and transphrasing strategies related to Chinese to English SI.grants from the Macau government.

Tongue cancer is an increasingly common disease with high morbidity. Besides clinical observation, biomedical imaging techniques have been investigated for early detection of tongue cancer. In this paper, we proposed a co-registered dual-modality photoacoustic (PA) and ultrasound imaging technique to simultaneously map the functional and structural information of human tongue, which has the potential to detect and diagnose tongue cancer in early stage. The imaging probe comprises a 20-MHz side-view focused transducer for ultrasound imaging and PA detection, a light path constructed by a multimode optical fiber, and a prism for PA illumination. Phantom experiments were conducted to evaluate the performance of the system including penetration depth, spatial resolution and signal-to-noise ratio. In vivo imaging of animal tumor and human tongue was carried out to show the feasibility of the proposed technique to detect tumor lesions in human tongue. The results of phantom and in vivo experiments suggest that the proposed technique has the potential to detect the early-stage cancer lesions in human tongue.

Human albumin (HA) is a very important blood product which requires strict quality control strategy. Acid precipitation is a key step which has a great effect on the quality of final product. Therefore, a new method based on quality by design (QbD) was proposed to investigate the feasibility of realizing online quality control with the help of near infrared spectroscopy (NIRS) and chemometrics. The pH value is the critical process parameter (CPP) in acid precipitation process, which is used as the end-point indicator. Six batches, a total of 74 samples of acid precipitation process, were simulated in our lab. Four batches were selected randomly as calibration set and remaining two batches as validation set. Then, the analysis based on material information and three different variable selection methods, including interval partial least squares regression (iPLS), competitive adaptive reweighted sampling (CARS) and correlation coe±cient (CC) were compared for eliminating irrelevant variables. Finally, iPLS was used for variables selection. The quantitative model was built up by partial least squares regression (PLSR). The values of determination coe±cients (R2c and R2p ), root mean squares error of prediction (RMSEP), root mean squares error of calibration (RMSEC) and root mean squared error of cross validation (RMSECV) were 0.969, 0.953, 0.0496, 0.0695 and 0.0826, respectively. The paired t test and repeatability test showed that the model had good prediction ability and stability. The results indicated that PLSR model could give accurate measurement of the pH value.

Functional near-infrared spectroscopy (fNIRS), as a new optical functional neuroimaging method, has been widely used in neuroscience research. In some research fields with NIRS, heartrate (HR) (or heartbeat) is needed as useful information to evaluate its influence, or to know the state of subject, or to remove its artifact. If HR (or heartbeat) can be detected with high accuracy from the optical intensity, this will undoubtedly benefit a lot to many NIRS studies. Previous studies have used the moving time window method or mathematical morphology method (MMM) to detect heartbeats in the optical intensity. However, there are some disadvantages in these methods. In this study, we proposed a method combining the periodic information of heartbeats and the operator of mathematical morphology to automatically detect heartbeats in the optical intensity. First the optical intensity is smoothed using a moving average filter. Then, the opening operator of mathematical morphology extracts peaks in the smoothed optical intensity. Finally, one peak is identi fied as a heartbeat peak if this peak is the maximum in a predefined point range. Through validation on experimental data, our method can overcome the disadvantages of previous methods, and detect heartbeats in the optical signal of fNIRS with nearly 100% accuracy.

A simple and novel method has been proposed to determine the enantiomeric composition of racemate praziquantel (PZQ) by using the analysis of ultraviolet (UV) spectroscopy combined with partial least squares (PLS). This method does not rely on the use of expensive carbohydrates such as cyclodextrins, but on the use of inexpensive sucrose, which is equally effective as carbohydrate. PZQ has two enantiomers. Through measuring the slight difference in the UV spectral absorption of PZQ due to different interactions between its two enantiomers and sucrose, the enantiomeric composition was determined by a quantitative model based on PLS analysis. The model showed that the correlation coe±cients of calibration set and validation set were 0.9971 and 0.9972, respectively. The root mean square error of calibration (RMSEC) and the root mean square error of prediction (RMSEP) were 0.0167 and 0.0129, respectively. Then, the independent data of PZQ tablets were also used to test how well the quantitative model of PLS predicted the enantiomeric composition. The ratio of S-PZQ in tablet was 0.492, determined by high-performance liquid chromatography as the reference value. Six solutions of the tablet samples were prepared, and the ratios of S-PZQ in tablet samples in the validation set were predicted by the PLS model. Their relative errors with the reference value were not more than 4%. Therefore, the established model could be accurate and employed to predict the enantiomeric compositions of PZQ tablets.

According to the speckle feature in Optical coherence tomography (OCT), images with speckle indicate not only noise but also signals, an improved wavelet hierarchical threshold filter (IWHTF) method is proposed. At first, a modified hierarchical threshold-selected algorithm is used to prevent signals from being removed by assessing suitable thresholds for different noise levels. Then, an improved wavelet threshold function based on two traditional threshold functions is proposed to trade-off between speckle removing and sharpness degradation. The de-noising results of an OCT finger skin image shows that the IWHTF method obtains better objective evaluation metrics and visual image quality improvement. When α=0.2, β=5.0 and K=1.2, the improved method can achieve 9.58 dB improvement in signal-to-noise ratio, with sharpness degraded by 3.81%.

Optical coherence tomography (OCT) has been widely applied to the diagnosis of eye diseases during the past two decades. However, valid evaluation methods are still not available for the clinical OCT devices. In order to assess the axial resolution of the OCT system, standard model eyes with micro-scale multilayer structure have been designed and manufactured in this study. Mimicking a natural human eye, proper Titanium dioxide (TiO2) materials of particles with different concentrations were selected by testing the scattering coe±cient of PDMS phantoms. The artificial retinas with multilayer films were fabricated with the thicknesses from 9.5 to 30 micrometers using spin coating technology. Subsequently, standard OCT model eyes were accomplished by embedding the retina phantoms into the artificial frames of eyes. For ease of measurement processing, a series of model eyes were prepared, and each contained films with three kinds of thicknesses. Considering the traceability and accuracy of the key parameters of the standard model eyes, the thicknesses of multilayer structures were verified using Thickness Monitoring System. Through the experiment with three different OCT devices, it demonstrated the model eyes fabricated in this study can provide an effective evaluation method for the axial resolution of an ophthalmic OCT device.