Clinical Value of Spectral Imaging Combined with MAR for CTA after Embolization of Intracranial Aneurysms

Objective: To evaluate the application value of combining spectral imaging and metal artifact reduction (MAR) in head and neck CTA after the embolization of intracranial aneurysms. Methods: We collected 37 patients who experienced embolization of intracranial aneurysms then received spectral imaging of head and neck CTA. Monochromatic images with energy ranging from 70～140 keV, 120 kVp-like mixed energic images, 70～140 keV MAR images, and 120 kVp-like MAR images were generated. The region of interest was placed on the area near the coil and with the most serious metal artifact. CT attenuation and standard deviation were measured, and artifact index (AI) and signal-noise ratio (SNR) were calculated. Two radiologists independently subjectively evaluated the metal artifact and the display of surrounding vessels using Likert 5 scales. The subjective scores and objective parameters between MAR and non-MAR images were compared. The Wilcoxon ranking test, paired sample t test, and independent sample t test were utilized to compare parameters between the groups. Results: MAR images had significantly lower AI than did non-MAR images for all eight monochromatic energies. When energies ranged from 80~110 keV, SNR was higher for MAR images than for non-MAR images, and the difference was statistically significant. With same energies, MAR images had higher artifact and vessel display scores than did non-MAR images. For non-MAR images, the different coil diameters did not make a statistical difference in AI and vessel display scores. For MAR images, a larger coil diameter (>8.79 mm) led to higher AI and lower vessel display scores than did normal diameters (≤8.79 mm). Conclusion: The combination of spectral imaging and MAR could effectively reduce the metal artifact of implants for the embolization of intracranial aneurysms and improve the surrounding vessel display. Moreover, the metal artifact reduction effect was more significant for the coils with smaller diameters

Efficient and bright warm-white electroluminescence from lead-free metal halides.

Solution-processed metal-halide perovskites are emerging as one of the most promising materials for displays, lighting and energy generation. Currently, the best-performing perovskite optoelectronic devices are based on lead halides and the lead toxicity severely restricts their practical applications. Moreover, efficient white electroluminescence from broadband-emission metal halides remains a challenge. Here we demonstrate efficient and bright lead-free LEDs based on cesium copper halides enabled by introducing an organic additive (Tween, polyethylene glycol sorbitan monooleate) into the precursor solutions. We find the additive can reduce the trap states, enhancing the photoluminescence quantum efficiency of the metal halide films, and increase the surface potential, facilitating the hole injection and transport in the LEDs. Consequently, we achieve warm-white LEDs reaching an external quantum efficiency of 3.1% and a luminance of 1570 cd m-2 at a low voltage of 5.4 V, showing great promise of lead-free metal halides for solution-processed white LED applications

Revealing the crystalline packing structure of Y6 in the active layer of organic solar cells: the critical role of solvent additives

The bulk heterojunction (BHJ) morphology of photovoltaic materials is crucial to the fundamental optoelectronic properties of organic solar cells (OSCs). However, in the photoactive layer, the intrinsic crystalline packing structure of Y6, currently the hallmark molecule among Y-series non-fullerene acceptors (NFAs), has not been unambiguously determined. Here, employing grazing-incidence wide-angle X-ray scattering (GIWAXS), we managed to uncover the intrinsic crystalline packing structure of Y6 in the BHJ active layer of OSCs, which is found to be different from its single-crystal structure reported previously. Moreover, we find that solvent additive 1-chloronaphthalene (CN) can induce highly ordered packing of Y6 in BHJ thin films. With the help of atomistic molecular dynamics simulations, it is revealed that π-π interactions generally exist between naphthalene derivatives and IC terminals of Y6 analogues, which would essentially improve their long-range ordering. Our work reveals the intrinsic crystalline packing structure of Y6 in the BHJ active layer as well as its crystallization mechanism in thin films, thus providing direct correlations between this crystalline packing and the device characteristics and photophysical properties.Knut och Alice Wallenbergs StiftelseImmediate accessThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Utilization of exterior surface dimples for stream-wise force reduction for a circular cylinder in cross-flow

Applying dimples on spherical bluff bodies have been found to be a major technique to control the surface flow and reduce the stream-wise force. However, not much work has been done on dimple applications on cylindrical Objects . This research project aims to investigate, firstly, whether the stream-wise force on a circular cylinder could be reduced by using dimples on its outer surface. Secondly, if it could, whether there is an optimum design that gives the biggest force reduction. Thirdly, what the roles of different approaches in this project might be? In order to find answers to these questions, experimental and computational methods have been used. One smooth and three dimpled cylinders have been tested. It was found that applying dimples on the outer surface of a cylinder is very effective in reducing stream-wise force. Drag coefficient significantly reduced by 17% to 48% depending on different Reynolds numbers. However, the dimpled design did not seem to be the key factor of the reduction, and the level of drag reduction was found to be insensitive to different dimpled patterns. Furthermore, it has also been found that CFD method would not be suitable as the research tool for this project because of its demanding requirement in computer power. Therefore, rig tests remained the primary method for this project. In addition, flow visualization technique was also used to show the wake region behind both the smooth and dimpled cylinders. It was clear that a smaller wake was associated with the dimpled case, which resulted in the pressure drag on the dimpled cylinder being smaller than for the smooth cylinder.This thesis is not currently available in OR

Evaluation of the solvent water effect on high solids saccharification of alkali-pretreated sugarcane bagasse

Solvent water is an essential factor for high solids enzymatic hydrolysis. To investigate its effect on substrate conversion efficiency in high solids hydrolysis of sugarcane bagasse (SCB), oleyl alcohol was used to partially substitute the solvent water. The results in batch hydrolysis tests in which diverse ratio of solvent water was replaced found that the majority of the substrate was insoluble. Then high solids fedbatch hydrolysis with the reaction solution mixed with solvent water and oleyl alcohol in the ratio of 3: 1 (solids concentration correspond to 24% (w/v)) was carried out at the final real solids loading of 18% (w/v). The produced sugars were found to be less than pure water system, which indicated that water played a significant role in high solids hydrolysis process, and solids effect was related to the solvent water content. (C) 2017 Elsevier Ltd. All rights reserved

Xylo-oligosaccharides and Ethanol Production from Liquid Hot Water Hydrolysate of Sugarcane Bagasse

With the objective of maximizing the use of liquid hot water hydrolysate of sugarcane bagasse, xylo-oligosaccharides and ethanol were respectively produced by the methods of purification and microbial fermentation. The processes of purification with activated charcoal, overliming, solvent extraction, vacuum evaporation, and use of an ion exchange resin were evaluated, and the results indicated that anion exchange chromatography performed well in terms of by-product removal. The recovery and purity of xylo-oligosaccharides reached 92.0% and 90.4%, respectively, using column chromatography with the resin LS30 at a flow rate of 2 mL/min at 25 degrees C. The hydrolysate was used in ethanol fermentation with Pichia stipitis CBS6054 followed by the production of fermentable saccharides and detoxification. The highest ethanol concentration was 4.12 g/L with a theoretical yield of 47.9% for the hydrolysate after xylanase digestion and resin detoxification, similar to the data of the control experiment, which had an ethanol concentration of 4.64 g/L and a yield of 49.6%. However, the former had a higher ethanol productivity of 0.0860 g/(L.h), and the highest ethanol concentration appeared 12 to 24 h earlier compared to the control. This study suggests that combined generation of xylo-oligosaccharides and cellulosic ethanol could help maximize profits for a cane sugar factory

Improved Ethanol Production Based on High Solids Fed-Batch Simultaneous Saccharification and Fermentation with Alkali-Pretreated Sugarcane Bagasse

Alkali-pretreated sugarcane bagasse fiber was subjected to fed-batch simultaneous saccharification and fermentation (SSF) with a pre-hydrolysis process to increase the solids loading and produce a high concentration of ethanol. The hydrolysis medium and yeast feeding modes were investigated to determine suitable conditions for high sugar yield and ethanol production. Batch addition resulted in a cumulative substrate concentration of up to 36% (w/v) and enhanced ethanol concentrations, while ethanol conversion efficiency gradually declined. Enzymatic pre-hydrolysis and fermentation with fed-batch mode contributed to the SSF process. The highest ethanol concentration was 66.915 g/L with the conversion efficiency of 72.89%, which was achieved at 30% (w/v) solids content after 96 h of fermentation. Hydrolyzed medium and yeast were added in batch mode at 24 h of enzymatic hydrolysis and fermentation, respectively. Thus, combining the fed-batch mode with pre-hydrolysis SSF produced a high yield of ethanol

INDUCTION OF HIGHLY ACTIVE beta-GLUCOSIDASE FROM BIOMASS MATERIALS AND ITS APPLICATION ON LIGNOCELLULOSE HYDROLYSIS AND FERMENTATION

To obtain highly active beta-glucosidase, low value agricultural residues were used to induce enzyme production. The results showed that rice bran was the best substrate to induce beta-glucosidase, likely due to its high magnesium, potassium, and calcium content. The optimum temperature and pH of beta-glucosidase were 65 degrees C and 4.8, respectively. This enzyme was thermo-tolerant and fairly stable, with a long half-life of 15 days at 50 degrees C. In addition, the enzyme activity was best stimulated in a concentration of 10% (v/v) ethanol. The effects of beta-glucosidase on fed-batch hydrolysis of cellulose and high-temperature simultaneous saccharification and fermentation (SSF) were examined. With a cellulase loading of 10 FPU/g of substrate and a beta-glucosidase loading of 15 IU/g of substrate, the final substrate loading of 35% dry mass, sugar concentration could attain 225.84 g/L after 120 h of hydrolysis. When the fed-batch SSF process was performed with Kluyveromyces marxianus NCYC 587 operated at 42 degrees C, after 72 h of fermentation, the maximum ethanol concentration was approximately 49.07 g/L, indicating that beta-glucosidase was suitable for lignocellulose conversion into ethanol