Field Size Evaluation with a High Resolution 2D Diode Array for Variable-Aperture Collimators Used in Robotic Radiosurgery

Robotic radiosurgery/Radiotherapy is increasingly adopted in clinics, and quality assurance (QA) of CyberKnife’s variable-aperture IrisTM collimators requires sub-millimeter precision. Conventional film-based QA for the 12 IrisTM cone sizes (ranging from 5 to 60 mm) is both time consuming (120 minutes for all or 30 minutes for 3 cone sizes) and highly experience dependent. To improve the efficiency, a high-resolution 2D diode detector array, sampling every 2.5 mm, was evaluated for IrisTM aperture size QA. This study focused on a spatial frequency analysis, a dose profile reconstruction, and a sensitivity study to beam size variances. Dose profiles of the 12 cones scanned with a high-resolution diode in a water tank were utilized as the gold standard for comparison. Spatial Fourier transform of these profiles were analyzed to explore applicable sampling frequency. Next, the dose profiles were artificially sampled with a 2.5 mm gap, and then interpolated using a Python-based cubic B-spline. Finally, sensitivity of the diode array system to various field sizes was measured by changing source to detector distance. We found, utilizing the diodes system, QA time was reduced to less than 10 minutes. Spatial frequency of the dose profile showed little contribution beyond 0.2 mm-1, so a Nyquist sampling of 0.4 mm-1 is appropriate for dose verification, corresponding to a 2.5 mm gap. Dose profiles were reconstructed using Cubic B-spline with good agreements to nominal for cones 7.5 mm and larger. The measured IrisTM size using the SRS MapCheck had a standard error of ±0.12 mm. Primarily, the 2D Diode array with a spatial resolution 0.4 mm-1 is appropriate for dose verification for these cones above 7.5 mm, and its application would substantially improve IrisTM QA efficiency.

Quantification of six bioactive compounds in Zhenqi Fuzheng preparation by high-performance liquid chromatography coupled with diode array detector and evaporative light scattering detector

A simple and accurate high-performance liquid chromatography（HPLC）coupled with diode array detector（DAD）and evaporative light scattering detector（ELSD）was established for the determination of six bioactive compounds in Zhenqi Fuzheng preparation（ZFP）.The monitoring wavelengths were 254,275 and 328 nm.Under the optimum conditions,good separation was achieved,and the assay was fully validated in respect of precision,repeatability and accuracy.The proposed method was successfully applied to quantify the six ingredients in 31 batches of ZFP samples and evaluate the variation by hierarchical cluster analysis（HCA）,which demonstrated significant variations on the content of these compounds in the samples from different manufacturers with different preparation procedures.The developed HPLC method can be used as a valid analytical method to evaluate the intrinsic quality of this preparation.

H_α/ D_α Measurements Based on Photo Diode Array in the HT-7 Tokamak

Photo Diode Array (PDA) has been successfully applied in HT-7 tokamak experiments. The PDA system is almost free of electromagnetic interference from the machine. The system is compact and inexpensive, and it is convenient to be arranged in experiment. With the PDA system, the particle confinement time (τp) has been systematically investigated. The relations such as τp on the center-line-averaged electron density (ne), τp on plasma current (Ip), and τp, on the toroidal magnetic field (Bt) have been obtained. The particle confinement under the Ion Berstain Wave (IBW) Heating has also been measured and analyzed.

Fast Tunable Wavelength Sources Based on the Laser Diode Array

We report a demonstration of a fast wavelength tunable source (TWS) based on the laser diode array coupled to the arrayed waveguide grating (AWG) multiplexer. The switching and optical characteristics of TWS make it a candidate for implementing the wavelength-division space switch fabric for an optical packet/burst switching.

Thermal analysis of GaN-based laser diode mini-array

Thermal characteristics of multiple laser stripes integrated into one chip is investigated theoretically in this paper. The temperature pattern of the laser diode mini-array packaged in a TO-can is analyzed and optimized to achieve a uniform temperature distribution among the laser stripes and along the cavity direction. The temperature among the laser stripes varies by more than 5 K if the stripes are equally arranged, and can be reduced to less than 0.4 K if proper arrangement is designed. For conventional submount structure, the temperature variation along the cavity direction is as high as 7 K, while for an optimized trapezoid submount structure, the temperature varies only within 0.5 K.

Novel method for the determination of five carbamate pesticides in water samples by dispersive liquid-liquid microextraction combined with high performance liquid chromatography

A novel method for the determination of five carbamate pesticides （metolcarb, carbofuran, carbaryl, isoprocard and diethofencard） in water samples was developed by dispersive liquid-liquid microextraction （DLLME） coupled with high performance liquid chromatography-diode array detector （HPLC-DAD）. Some experimental parameters that influence the extraction efficiency were studied and optimized to obtain the best extraction results. Under the optimum conditions for the method, the calibration curve was linear in the concentration range from 5 to 1000 ng mL^-1 for all the five carbamate pesticides, with the correlation coefficients （r^2） varying from 0.9984 to 0.9994. Good enrichment factors were achieved ranging from 80 to 177- fold, depending on the compound. The limits of detection （LODs） （S/N = 3） were ranged from 0.1 to 0.5 ng mL^-1. The method has been successfully applied to the analysis of the pesticide residues in environmental water samples.

Study on chromatographic fingerprint of sarcandra glabra (Thunb.) by microwave-assisted extraction coupled to HPLC/DAD

Microwave-assisted extraction(MAE)was used for extraction of effective components of sarcandra glabra(Thunb.),and then chromatographic fingerprint of sarcandra glabra(Thunb.)was studied by high performance liquid chromatography/diode array detector(HPLC/DAD).The conditions of MAE were optimized by an orthogonal experiment,and then the authentication and validation of the chromatographic fingerprint were conducted.Nine peaks were identified as common peaks in the fingerprint chromatograms,and isofraxidin was considered as a reference compound and quantified.Relative standard deviations of retention time and peak area of each component were less than 3% and 8%,respectively.Similarity and difference analysis were conducted by use of PCA and relation coefficient.Twenty batches of sarcandra glabra(Thunb.)samples from two different producing areas could be classified into two different groups in the PCA model.The results showed that MAE-HPLC/DAD method was simple,efficient and stable for the study of complex chromatographic fingerprint of sarcandra glabra(Thunb.),which could provide more reliable and precise information for quality evaluation.

Optical recordings reveal the differential distribution of glutamatergic transmission in the cochlear and vestibular nuclei in the newborn mouse brainstem

Objective Using optical imaging in brainstem slices, we studied evoked responses in the mouse cochlear (CN) and vestibular (VN) nuclei. Methods The use of optical imaging allowed us to visualize the spatiotemporal patterns of excitatory propagation in the CN and VN. Optical recordings can differentiate excitatory propagation in the ventral CN(VCN) from that in the dorsal CN(DCN). Furthermore, we assessed the relative distribution of NMDA and non-NMDA receptors in these regions using the glutamate antagonists APV (NMDA receptor antagonist) and CNQX (non-NMDA receptor antagonist) in mouse brainstem slices during postnatal days 1 to 3. Results The average sensitivity to APV was 99.1% in the VCN, 76.0% in the DCN and 64.9% in the VN. The average sensitivity to CNQX was 0.9% in the VCN, 24.0% in the DCN and 35.1% in the VN. These results indicate that the effect of APV dominated in the VCN, while both APV and CNQX were effective antagonists in the DCN and VN. In the VN, the distribution of APV-and CNQX-sensitive cells was almost completely uniform. However, in the DCN the distribution of APV-and CNQX-sensitive cells was highly complex. The area that was more sensitive to CNQX was located in the superficial layer of the DCN while the area with a higher sensitivity to APV was located progressively in the deep layer. Conclusion This optical recording data suggests that there is a differential distribution of NMDA and non-NMDA receptor mediated neurotransmission in the VCN, DCN and VN.

Spherical distribution structure of the semiconductor laser diode stack for pumping

A semiconductor laser diode stack is used for pumping and 8 semiconductor laser diode arrays of the stack are put on a sphere,and the output of every bar is specially off-axis compressed to realize high coupling efficiency.The output beam of this semiconductor laser diode stack is shaped by a hollow duct to the laser active medium.The efficiency of the hollow light pipe,which is used for semiconductor laser diode stack coupling,is analyzed by geometric optics and ray tracing.Geometric optics analysis diagnoses the reasons for coupling loss and guides the design of the structure.Ray tracing analyzes the relation between the structural parameters and the output characteristics of this pumping system,and guides parameter optimization.Simulation and analysis results show that putting the semiconductor laser diode arrays on a spherical surface can increase coupling efficiency, reduce the optimum duct length and improve the output energy field distribution.

Developing a Novel Single-Marker-Based Method for the Quantitative Evaluation of the Multiple Active Components in Corydalis yanhusuo W. T. Wang

Objective: This study was designed to develop a method for detecting differences in the chemical composition of Corydalis yanhusuo W. T. Wang using high-performance liquid chromatography with a diode array detector technology. Materials and Methods: We established a novel quantitative evaluation method for identifying multiple components in natural extracts using a single-marker method quantitative analysis of multi-components by single marker(QAMS). This method was then validated using eight alkaloid phytochemical markers designed to evaluate C. yanhusuo quality. Results: Our evaluations revealed good linearity(R^(2) ≥ 0.9991) within the range of tested concentrations for all eight alkaloids, with recovery ranging from 95.5% to 101.5%. The evaluations also returned stability results that fell within the acceptable range. Cluster analysis and Heatmap analyses were applied to classify and evaluate alkaloids across 21 different production areas. These results revealed a significant difference in the component profiles between samples from different origins. Conclusions: Thus, these data suggest that in the absence of a material reference, QAMS may help facilitate the stable production of C. yanhusuo. In addition, our data suggest that this method may have value as a promising alternative to common quality evaluations for controlling C. yanhusuo composition.

Simultaneous Determination of Seven Alkaloids in Fufang Zhenzhu Tiaozhi Capsule by HPLC Coupled with DAD

Objective To establish a reverse-phase liquid chromatography method for the determination of seven alkaloids (magnoflorine, columbamine, jatrorrhizine, epiberberine, coptisine, palmatine, and berberine) in Fufang Zhenzhu Tiaozhi Capsule. Methods Chromatography was performed on a Dionex Acclaim C 18 column (250 mm × 4.6 mm, 5.0 μm) at 30 ℃ .The mobile phase was composed of acetonitrile-potassium dihydrogen phosphate solution (0.015 mol/L, 40:60, including 1.7 g/L sodium dodecyl sulfate and phosphoric acid used to regulate pH value to 3.0), with a flow rate of 1.0 mL/min. The detection wavelength was 270 nm. Results The calibration curves of magnoflorine, columbamine, jatrorrhizine, epiberberine, coptisine, palmatine, and berberine were linear in the range of 1.07- 10.65, 0.78-7.55, 0.75-7.50, 1.60-15.95, 2.69-26.85, 2.31-23.10, and 6.04-60.40 mg/mL. The average recoveries of magnoflorine, columbamine, jatrorrhizine, epiberberine, coptisine, palmatine, and berberine were 101.0%, 101.2%, 100.1%, 100.0%, 100.1%, 101.1%, and 99.7%, respectively. Conclusion The method could be used for the quantitative determination of the preparation.

Quantitative Analysis and Chemical Fingerprint Similarity for Quality Control of the Seeds of Paeonia suffruticosa Andr. by HPLC

According to the General Office of the State Council of China, tree peony seeds（TPSs, Paeonia suffruticosa Andr.） are considered an emerging source for edible oil. In Chinese folk medicine, TPSs are used for alleviating waist and leg pain. In the present study, a simple, accurate and rapid fingerprint method based on high performance liquid chromatography with diode array detection（HPLe-DAD） was developed and validated to quantify the profiles of ten representative compounds in TPSs. All standard calibration curves exhibited good linearity（R2〉0.9995） in the I-IPLC-DAD analysis. The recovery of the standards ranged from 96.37% to 102.10%. The results show that stilbe- noids are the major constituents in TPSs, and their total content ranges from 25.71 mg/g to 54.03 mg/g. Suffruticosol A, suffruticosol B, trans-e-viniferm, ampelopsin E and paeoniflorin are the major components in methanol- water（80：20, volume ratio） extracts with average contents of 3.962, 12.264, 5.826, 14.060 and 12.755 rag/g, respec- tively. Additionally, 14 batches of seeds collected from different regions were used to establish a reference fingerprint Their similarity values were higher than 0.944 except for the sample（0.863） from Linxia. These results collectively indicate that the quantitative HPLC fingerprint method can serve as a prerequisite quality control for TPSs, and is a promising resource for developing new herbal or food products.