Fetal agenesis of the corpus callosum: Clinical and genetic analysis in a series of 40 patients.

OBJECTIVES: This study aimed to explore the genetic causes of agenesis of the corpus callosum (ACC) and assess the utility of karyotype analysis, copy number variation sequencing (CNV-seq), and whole-exome sequencing (WES) to genetically diagnose fetal ACC. METHODS: We retrospectively examined 40 fetuses diagnosed with ACC who underwent prenatal ultrasonography or magnetic resonance imaging between January 2019 and October 2023. Genetic tests were conducted on the fetuses using karyotype analysis or CNV-seq as the first-line diagnosis. WES was performed if aneuploid and pathogenic CNVs were excluded. RESULTS: Among the 40 fetuses, 29 (72 %) had non-isolated ACC and 11 (28 %) had isolated ACC. Cerebellar dysplasia and hydrocephalus were the most common abnormal developments in the central nervous system. Twenty-eight patients underwent karyotype analysis, with a detection rate of 14 % (4/28). Twenty-six patients underwent CNV-seq; three patients were found to have pathogenic CNVs, with a detection rate of 12 % (3/26). Thirty-three fetuses with no findings of karyotype analysis or CNV-seq were subsequently tested using WES, with a detection rate of 36 % (12/33). Overall, the total diagnostic yield was 48 % (19/40), and monogenic etiology accounted for 30 % (12/40). The genetic detection rate of fetal non-isolated ACC (62 %, 18/29) was higher than that of isolated ACC (9 %, 1/11). CONCLUSION: Prenatal genetic analysis of fetuses with ACC is clinically significant, with monogenic disorders being the main cause. WES may enhance the detection rate of fetuses with ACC with negative karyotype analysis or CNV-seq results.

Covalently Linking Reduced Graphene Oxide Facilitated Electrodeposition of MoS2 on Silicon Pyramidal Photocathode To Enhance Hydrogen Evolution.

In recent years, increasing attention has been paid to photoelectrochemical (PEC) hydrogen production owing to the utilization of sustainable solar energy and its promising performance. Silicon-based composites are generally considered ideal materials for PEC hydrogen production. However, slow reaction kinetics and poor stability are still key factors hindering the development of silicon-based photoelectrocatalysts. Herein, we present an n+-p Si pyramidal photocathode assembly method to load reduced graphene oxide (rGO) onto the surface of the n+-p Si pyramid by covalently linking (Si/rGO). rGO is utilized as a conductive layer to reduce the interfacial charge-transfer resistance. Then, MoS2 can be successfully electrodeposited on the surface of Si/rGO to form the Si/rGO/MoS2 composite, which possesses excellent PEC hydrogen evolution performance with a high and stable photocurrent of -41.6 mA cm-2 and a hydrogen evolution rate of about 18.1 µmol min-1 cm-2 under 0 V (vs RHE). The covalently linking rGO layer effectively enhances the transfer of photogenerated carriers between the Si substrate and MoS2. MoS2 provides abundant hydrogen evolution active sites, which accelerate the surface reaction kinetics, as well as a protective layer for the Si pyramidal array structure. This work provides a low-cost, convenient, and efficient way of preparing silicon-based photocathodes.

Halloysite-derived mesoporous silica with high ionic conductivity improves Li-S battery performance.

The slow Li+ transport rate in the thick sulfur cathode of the Li-S battery affects its capacity and cycling performance. Herein, Fe-doped highly ordered mesoporous silica material (Fe-HSBA-15) as a sulfur carrier of the Li-S battery shows high ion conductivity (1.10 mS cm-1) and Li+ transference number (0.77). The Fe-HSBA-15/S cell has an initial capacity of up to 1216.7 mA h g-1 at 0.2C and good stability. Impressively, at a high sulfur load of 4.34 mg cm-2, the Fe-HSBA-15/S cell still maintains an area specific capacity of 4.47 mA h cm-2 after 100 cycles. This is because Fe-HSBA-15 improves the Li+ diffusion behavior through the ordered mesoporous structure. Theoretical calculations also confirmed that the doping of iron enhances the adsorption of polysulfides, reduces the band gap and makes the catalytic activity stronger.

Design of a Subretinal Injection Robot Based on the RCM Mechanism.

This study presents an investigation focusing on the advancement of a robot designed for subretinal injections in the context of macular degeneration treatment. The technique of subretinal injection surgery stands as the most efficacious approach for the successful transplantation of stem cells into the retinal pigment epithelium layer. This particular procedure holds immense significance in advancing research and implementing therapeutic strategies involving retinal stem cell transplantation. The execution of artificial subretinal surgery poses considerable challenges which can be effectively addressed through the utilization of subretinal injection surgery robots. The development process involved a comprehensive modeling phase, integrating computer-aided design (CAD) and finite element analysis (FEA) techniques. These simulations facilitated iterative enhancements of the mechanical aspects pertaining to the robotic arm. Furthermore, MATLAB was employed to simulate and visualize the robot's workspace, and independent verification was conducted to ascertain the range of motion for each degree of freedom.

Contour similarity and its implication on inverse prostate SBRT treatment planning.

PURPOSE: Success of auto-segmentation is measured by the similarity between auto and manual contours that is often quantified by Dice coefficient (DC). The dosimetric impact of contour variability on inverse planning has been rarely reported. The main aim of this study is to investigate whether automatically generated organs-at-risk (OARs) could be used in inverse prostate stereotactic body radiation therapy (SBRT) planning and whether the dosimetric parameters are still clinically acceptable after radiation oncologists modify the OARs. METHODS AND MATERIALS: Planning computed tomography images from 10 patients treated with SBRT for prostate cancer were selected and automatically segmented by commercially available atlas-based software. The automatically generated OAR contours were compared with the manually drawn contours. Two volumetric modulated arc therapy (VMAT) plans, autoRec-VMAT (where only automatically generated rectums were used in optimization) and autoAll-VMAT (where automatically generated OARs were used in inverse optimization) were generated. Dosimetric parameters based on the manually drawn PTV and OARs were compared with the clinically approved plans. RESULTS: The DCs for the rectum contours varied from 0.55 to 0.74 with a mean value of 0.665. Differences of D95 of the PTV between autoRec-VMAT and manu-VMAT plans varied from 0.03% to -2.85% with a mean value of -0.64%. Differences of D0.03cc of manual rectum between the two plans varied from -0.86% to 9.94% with a mean value of 2.71%. D95 of PTV between autoAll-VMAT and manu-VMAT plans varied from 0.28% to -2.9% with a mean value -0.83%. Differences of D0.03cc of manual rectum between the two plans varied from -0.76% to 6.72% with a mean value of 2.62%. CONCLUSION: Our study implies that it is possible to use unedited automatically generated OARs to perform initial inverse prostate SBRT planning. After radiation oncologists modify/approve the OARs, the plan qualities based on the manually drawn OARs are still clinically acceptable, and a re-optimization may not be needed.

Perceptual scale expansion: A natural design for improving the precision of motor control.

Space perception is systematically biased. Few theories of spatial bias address the possible functional advantages of mechanisms that produce spatial biases. The scale expansion hypothesis proposes that many spatial biases are due to the perceptual expansion of visual angles, which acts somewhat like a natural magnifying glass in vision. The present study examined the idea that visual expansion may improve motor precision (i.e., reduce motor variability) in movements when using closed-loop control but not when using open-loop control. Experiment 1 tested this idea in an online tracking task (closed-loop control), whereas Experiment 2 tested it in a fast-hitting task (open-loop control). The results were consistent with the hypothesis. To rule out the effect of the task difference (i.e., tracking vs fast hitting), Experiment 3 examined the effect of visual expansion on the variability of motor performance in a line-reproduction task. The control type (closed-loop or open-loop) was manipulated by the form of visual feedback (online or offline). The results were again consistent with the present assumption. Taken together, the present data suggest that perceptual expansion in vision improves motor-control precision when using closed-loop control (but not when using open-loop control), which supports the scale expansion hypothesis. In addition, the present findings also improve our understanding of how visual error amplification affects motor control.

Development and validation of a three-dimensional deep learning-based system for assessing bowel preparation on colonoscopy video.

Background: The performance of existing image-based training models in evaluating bowel preparation on colonoscopy videos was relatively low, and only a few models used external data to prove their generalization. Therefore, this study attempted to develop a more precise and stable AI system for assessing bowel preparation of colonoscopy video. Methods: We proposed a system named ViENDO to assess the bowel preparation quality, including two CNNs. First, Information-Net was used to identify and filter out colonoscopy video frames unsuitable for Boston bowel preparation scale (BBPS) scoring. Second, BBPS-Net was trained and tested with 5,566 suitable short video clips through three-dimensional (3D) convolutional neural network (CNN) technology to detect BBPS-based insufficient bowel preparation. Then, ViENDO was applied to complete withdrawal colonoscopy videos from multiple centers to predict BBPS segment scores in clinical settings. We also conducted a human-machine contest to compare its performance with endoscopists. Results: In video clips, BBPS-Net for determining inadequate bowel preparation generated an area under the curve of up to 0.98 and accuracy of 95.2%. When applied to full-length withdrawal colonoscopy videos, ViENDO assessed bowel cleanliness with an accuracy of 93.8% in the internal test set and 91.7% in the external dataset. The human-machine contest demonstrated that the accuracy of ViENDO was slightly superior compared to most endoscopists, though no statistical significance was found. Conclusion: The 3D-CNN-based AI model showed good performance in evaluating full-length bowel preparation on colonoscopy video. It has the potential as a substitute for endoscopists to provide BBPS-based assessments during daily clinical practice.

Social Avoidance and Social Adjustment: The Moderating Role of Emotion Regulation and Emotion Lability/Negativity Among Chinese Preschool Children.

The present study explored the role of emotion regulation and emotion lability/negativity as a moderator in the relation between child social avoidance and social adjustment (i.e., interpersonal skills, asocial behavior, peer exclusion) in Chinese culture. Participants were N = 194 children (102 boys, 92 girls, M age = 70.82 months, SD = 5.40) recruited from nine classrooms in two public kindergartens in Shanghai, People's Republic of China. Multi-source assessments were employed with mothers rating children's social avoidance and teachers rating children's emotion regulation, emotion lability/negativity and social adjustment outcomes. The results indicated that the relations between social avoidance and social adjustment difficulties were more negative among children lower in emotion regulation, but not significant for children with higher emotion regulation. In contrast, the relations between social avoidance and social adjustment difficulties were more positive among children higher in emotion lability/negativity, but not significant for children with lower emotion lability/negativity. This study informs us about how emotion regulation and emotion lability/negativity are jointly associated with socially avoidant children's development. As well, the findings highlight the importance of considering the meaning and implication of social avoidance in Chinese culture.

A waste newspaper/multi-walled carbon nanotube/TiO2 interlayer for improving the cycling stability of lithium-sulfur batteries by anchoring polysulfides.

Owing to the high theoretical specific capacity and energy density, lithium-sulfur (Li-S) batteries are considered an ideal candidate for next-generation rechargeable batteries. Whereas, the shuttle effect of polysulfides limits the utilization of active materials, reducing the electrochemical performance of lithium-sulfur batteries. Herein, by directly using waste newspapers as a substrate, a waste newspaper/multi-walled carbon nanotube/TiO2 (NMT) interlayer has been prepared for stable Li-S batteries. In the composite interlayer, the newspaper functions as the basic frame for loading materials. Carbon materials absorbed by the newspaper provide both a conductive pathway and physical adsorption of lithium polysulfides (LiPS). Meanwhile, TiO2 inhibits the dissolution of LiPS in the electrolyte by strong chemical bonding. The morphology and spectra prove that the newspaper plays a key frame role in the functional composite interlayer. The electrochemical analyses demonstrate that the as-fabricated interlayer can obviously improve the cycling performance of Li-S battery. At a 0.5 C (1.0 C = 1675 mA h g-1) charge-discharge current density, after 500 cycles, the Li-S battery with NMT interlayer still exhibits a discharge capacity of 463.7 mA h g-1 with a low capacity decay per cycle of 0.071%.

Memories of motor adaptation do not necessarily decay with behavioral unlearning.

Motor adaptation reshapes behaviors to habituate novel predictable demands caused by dramatic changes in our body (or environment). In the absence of error signals, behaviors rapidly return to the manner before adaptation. It is still in debate whether this behavioral unlearning is due to memory decay. Recent studies suggested that unlearning may be related to the detection of a context change between adaptation phase and error-absent phase. This context-dependent idea is extended in the present study, which examined the motor adaptation in a ball-tossing task. To facilitate the manipulation of the task and the measurement of the behavior, this tossing task was conducted in a virtual environment. Experiment 1 found that unlearning was more likely to occur when the context in the adaptation phase was less similar to that in the error-absent phase. Experiment 2 further demonstrated that the memory of motor adaptation can bias behavior even after behavioral unlearning. Experiment 3 confirmed that the results in Experiment 1 and 2 were not artifacts. These findings indicate that memories of adaptation are independent of behavioral unlearning, and the contextual similarity between adaptation and error-absent phase determines the unlearning rate.

Which Dose Specification Should Be Used for NRG Radiation Therapy Trials: Dose-to-Medium or Dose-to-Water?

PURPOSE: To compare the doses calculated by the Analytical Anisotropic Algorithm (AAA), Acuros dose-to-medium, and Acuros dose-to-water for the patients with lung cancer treated at our institution and show that further investigation and clarification are needed about what dose specifications should be used for NRG clinical trials. METHODS AND MATERIALS: Twenty-one patients with lung cancer who previously received intensity modulated radiation therapy or volumetric modulated arc therapy-based treatments at our institution were analyzed by recalculating their plans for each one with the AAA algorithm (reviewed and approved by our radiation oncologists) and with both reporting modes of the Acuros algorithm. All plans used the same monitor units as the original approved plan and a 2.5-mm grid size. For each patient, D100 of clinical target volume (CTV) and CTV coverage ratios in each plan were compared, and dose distributions and dose-volume histograms calculated by AAA, Acuros dose-to-water (Dw,m), and Acuros dose-to-medium (Dm,m) were compared as well. RESULTS: Differences between CTV D100 calculated by AAA and Acuros Dm,m were larger than the differences between AAA and Acuros XB Dw,m for all patients. When D100 of CTV was evaluated, the largest difference between AAA and Acuros Dm,m was 14.12% and between AAA and Acuros XB Dw,m was 3.68%. The average differences between the CTV D100 calculated by AAA and Acuros Dm,m was 5.39%. Coverage ratio between Acuros Dm,m and AAA ranges from 51.08% to 100% with an average of 91.32%; coverage ratio between Acuros Dw,m and AAA ranges from 87.2% to 100.41% with average of 98.94%; coverage ratio between Acuros Dm,m and Acuros Dw,m ranges from 58.58% to 100% with an average of 92.03%. CONCLUSIONS: The present study shows large and systematic differences in doses calculated by AAA and Acuros Dm,m. Therefore, further investigation and clarification are needed about which dose reporting mode should be used.

Correlation between real-time intraoperative and postoperative dosimetry and its implications on intraoperative planning.

PURPOSE: The purpose of this study was to study the correlation between intraoperative and postimplant dosimetry. We investigated the correlation between prostate (V150) and urethra (D30, D5) dose limits, and whether it is possible to increase prostate D90 and V100 in intraoperative planning without violating postimplant urethra and rectum dose limits. METHODS AND MATERIALS: Seventy-nine patients who underwent real-time ultrasound-guided prostate implants using intraoperative planning from 2013 to 2017 were analyzed. Forty-one of the 79 implants were 125I as monotherapy and the remainder was 103Pd as boost to external beam radiation therapy or external beam radiation therapy plus androgen deprivation therapy. Prescriptions followed the guidelines of AAPM TG-137. The urethra was catheterized during intraoperative implantation and postimplant imaging to facilitate the urethra identification. T2-cubed MRI and CT were acquired on the same day and about 1 month after the low-dose-rate procedure, and MRI was later fused with the CT scan for accurate delineation of the prostate and postimplant dosimetry evaluation. An institutionally based peer-review process and document procedure were established based on national recommendations. Correlation of dose parameters: D90, V150, V100 of prostate, D30, D5 of urethra, and V100 of rectum between intraoperative and postimplant plans were evaluated. RESULTS: D90 and V100 declined for all implants between intraoperative and postimplant dosimetry. On average, D90 declined by 17.5% and 21.7% for 125I and 103Pb implants, respectively. V100 declined for all implants between intraoperative and postimplant dosimetry but less pronounced. Prostate V150 and urethra D30 and D5 also showed different tendency of decline. Of the 79 implants, 60 did not meet the postimplant dosimetry target for prostate (V150 ≤ 50%), and 46 of the 60 implants met the optimal dosimetry targets for both D30 (<125%) and D5 (<150%), and the other 14 of the 60 implants failed to meet either the D30 or the D5 limits. All the implants met the postimplant target dose for rectum: V100≤ 1.3 cc. CONCLUSION: Intraoperative implant dosimetry could not accurately predict postimplant dosimetry; however, to avoid underdosage of prostate, intraoperative D90 should be close to 120% of prescribed dose and V100 needs to be close to 100% of prescribed dose. Prostate V150> 50% does not necessarily indicate the violation of urethra D30 and D5 dose limits. For most of the implants, target intraoperative D90 and V100 could be raised without violating urethra D30 and D5 limits recommended by American Brachytherapy Society in postimplant evaluation.

Characteristics of wooden intraocular foreign body by magnetic resonance imaging in rabbits.

OBJECTIVE: Intraocular foreign body (IOFB), a frequent cause of ocular trauma, causes serious damage to the eyes. This study was designed to elaborate and compare the characteristics of different magnetic resonance imaging (MRI) sequences in detecting wooden IOFBs in rabbits. METHODS: The right vitreous of 24 healthy rabbits was randomly implanted with diverse wooden foreign bodies (diameter φ = 0.2 mm). The T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), proton density-weighted imaging (PDWI), and susceptibility-weighted imaging (SWI) sequences were applied individually 2 weeks after the implantation. RESULTS: IOFBs were detected as linear low signals on T1WI, T2WI, PDWI, and SWI (SWI image). The detectable rates of poplar wood with a length of 0.5 mm were 0%, 50%, 0%, and 67% for T1WI, T2WI, PDWI, and SWI, respectively. SWI and T2WI sequences exhibited higher sensitivity than T1WI and PDWI. The detectable rates of the first three SWI sequences (magnitude, phase, and SWI) were all 67%, which was higher than that of the minimum intensity projection sequence (33%). CONCLUSION: MRI is practicable in the diagnosis of wooden IOFBs. SWI and T2WI are optimal for the integrated diagnosis of wooden IOFBs and could be used for diagnosis and immediate treatment.

The thalamo-cortical resting state functional connectivity and abstinence-induced craving in young smokers.

Craving is a significant predicator of smoking relapse. Thus, revealing the neural correlates of craving to smoke in young smokers is important to improve the success of quit attempts. The abstinence-induced craving to smoke has not been explored extensively, although previous studies had investigated the neural substrates of cue-induced craving. Especially, the critical roles of thalamus had been revealed in cigarettes smoking. However, the implication of thalamus resting state functional connectivity (RSFC) in abstinence-induced craving remains unclear. In the current study, by employing a within-subject design in 25 young smokers, both the left and right thalamus RSFC patterns differences were investigated between smoking abstinence condition and smoking satiety condition in young smokers. Moreover, a correlation analysis was employed to assess the relationship between these RSFC changes and abstinence-induced changes in subjective craving. We found young smokers in abstinence state showed reduced RSFC between the left thalamus and right dorsal lateral prefrontal cortex (dlPFC) as well as the right anterior cingulate cortex (ACC) compared with smoking satiety state. There were no significant different RSFC of right thalamus detected across the two sessions. Additionally, the left thalamus-right dlPFC RSFC changes were correlated with the changes in craving induced by 12-h abstinence (i.e., abstinence minus satiety). The present findings provides new evidence that abstinence-induced cravings to smoke are associated with abnormal thalamus RSFC and may shed new insights into the neural mechanism of abstinence-induced craving in young smokers.

Thickness-Dependent DC Electrical Breakdown of Polyimide Modulated by Charge Transport and Molecular Displacement.

Polyimide has excellent electrical, thermal, and mechanical properties and is widely used as a dielectric material in electrical equipment and electronic devices. However, the influencing mechanism of sample thickness on electrical breakdown of polyimide has not been very clear until now. The direct current (DC) electrical breakdown properties of polyimide as a function of thickness were investigated by experiments and simulations of space charge modulated electrical breakdown (SCEB) model and charge transport and molecular displacement modulated (CTMD) model. The experimental results show that the electrical breakdown field decreases with an increase in the sample thickness in the form of an inverse power function, and the inverse power index is 0.324. Trap properties and carrier mobility were also measured for the simulations. Both the simulation results obtained by the SCEB model and the CTMD model have the inverse power forms of breakdown field as a function of thickness with the power indexes of 0.030 and 0.339. The outputs of the CTMD model were closer to the experiments. This indicates that the displacement of a molecular chain with occupied deep traps enlarging the free volume might be a main factor causing the DC electrical breakdown field of polyimide varying with sample thickness.

Carrier Transport and Molecular Displacement Modulated dc Electrical Breakdown of Polypropylene Nanocomposites.

Dielectric energy storage capacitors have advantages such as ultra-high power density, extremely fast charge and discharge speed, long service lifespan and are significant for pulsed power system, smart power grid, and power electronics. Polypropylene (PP) is one of the most widely used dielectric materials for dielectric energy storage capacitors. It is of interest to investigate how to improve its electrical breakdown strength by nanodoping and the influencing mechanism of nanodoping on the electrical breakdown properties of polymer nanocomposites. PP/Al2O3 nanocomposite dielectric materials with various weight fraction of nanoparticles are fabricated by melt-blending and hot-pressing methods. Thermally stimulated current, surface potential decay, and dc electrical breakdown experiments show that deep trap properties and associated molecular chain motion are changed by incorporating nanofillers into polymer matrix, resulting in the variations in conductivity and dc electrical breakdown field of nanocomposite dielectrics. Then, a charge transport and molecular displacement modulated electrical breakdown model is utilized to simulate the dc electrical breakdown behavior. It is found that isolated interfacial regions formed in nanocomposite dielectrics at relatively low loadings reduce the effective carrier mobility and strengthen the interaction between molecular chains, hindering the transport of charges and the displacement of molecular chains with occupied deep traps. Accordingly, the electrical breakdown strength is enhanced at relatively low loadings. Interfacial regions may overlap in nanocomposite dielectrics at relatively high loadings so that the effective carrier mobility decreases and the interaction between molecular chains may be weakened. Consequently, the molecular motion is accelerated by electric force, leading to the decrease in electrical breakdown strength. The experiments and simulations reveals that the influence of nanodoping on dc electrical breakdown properties may origin from the changes in the charge transport and molecular displacement characteristics caused by interfacial regions in nanocomposite dielectrics.

Clinical implementation and evaluation of the Acuros dose calculation algorithm.

PURPOSE: The main aim of this study is to validate the Acuros XB dose calculation algorithm for a Varian Clinac iX linac in our clinics, and subsequently compare it with the wildely used AAA algorithm. METHODS AND MATERIALS: The source models for both Acuros XB and AAA were configured by importing the same measured beam data into Eclipse treatment planning system. Both algorithms were validated by comparing calculated dose with measured dose on a homogeneous water phantom for field sizes ranging from 6 cm × 6 cm to 40 cm × 40 cm. Central axis and off-axis points with different depths were chosen for the comparison. In addition, the accuracy of Acuros was evaluated for wedge fields with wedge angles from 15 to 60°. Similarly, variable field sizes for an inhomogeneous phantom were chosen to validate the Acuros algorithm. In addition, doses calculated by Acuros and AAA at the center of lung equivalent tissue from three different VMAT plans were compared to the ion chamber measured doses in QUASAR phantom, and the calculated dose distributions by the two algorithms and their differences on patients were compared. Computation time on VMAT plans was also evaluated for Acuros and AAA. Differences between dose-to-water (calculated by AAA and Acuros XB) and dose-to-medium (calculated by Acuros XB) on patient plans were compared and evaluated. RESULTS: For open 6 MV photon beams on the homogeneous water phantom, both Acuros XB and AAA calculations were within 1% of measurements. For 23 MV photon beams, the calculated doses were within 1.5% of measured doses for Acuros XB and 2% for AAA. Testing on the inhomogeneous phantom demonstrated that AAA overestimated doses by up to 8.96% at a point close to lung/solid water interface, while Acuros XB reduced that to 1.64%. The test on QUASAR phantom showed that Acuros achieved better agreement in lung equivalent tissue while AAA underestimated dose for all VMAT plans by up to 2.7%. Acuros XB computation time was about three times faster than AAA for VMAT plans, and computation time for other plans will be discussed at the end. Maximum difference between dose calculated by AAA and dose-to-medium by Acuros XB (Acuros_Dm,m ) was 4.3% on patient plans at the isocenter, and maximum difference between D100 calculated by AAA and by Acuros_Dm,m was 11.3%. When calculating the maximum dose to spinal cord on patient plans, differences between dose calculated by AAA and Acuros_Dm,m were more than 3%. CONCLUSION: Compared with AAA, Acuros XB improves accuracy in the presence of inhomogeneity, and also significantly reduces computation time for VMAT plans. Dose differences between AAA and Acuros_Dw,m were generally less than the dose differences between AAA and Acuros_Dm,m . Clinical practitioners should consider making Acuros XB available in clinics, however, further investigation and clarification is needed about which dose reporting mode (dose-to-water or dose-to-medium) should be used in clinics.

Using High-Resolution 3D Magnetic Resonance Imaging to Quantitatively Analyze the Shape of Eyeballs with High Myopia and Provide Assistance for Posterior Scleral Reinforcement.

PURPOSE: To quantitatively analyze the shape of eyes with high myopia and provide assistance for posterior scleral reinforcement (PSR) using high-resolution three-dimensional (3D) magnetic resonance imaging (MRI). METHOD: In all, 260 eyes of 134 patients with high myopia were assessed in this study; 120 emmetropic volunteers were enrolled as a control group. The subjects were examined using 3D T2-weighted CUBE sequences. RESULTS: The eyeballs' axial, horizontal, and vertical lengths were longer and their volume was larger in the subjects with high myopia than in those with emmetropia. The sites of the four recti and optic nerve attachment to the eye were clearly seen on 3D MRI, and the geometric information could be quantified for PSR preparation. The scleral strip was revealed by 3D MRI after surgery. CONCLUSIONS: 3D MRI can quantitatively analyze the shape of eyes with high myopia. 3D MRI examination might be necessary before and after PSR for preoperative preparation and postoperative assessment.

Dielectric and Carrier Transport Properties of Silicone Rubber Degraded by Gamma Irradiation.

Silicone rubber (SiR) is used as an insulating material for cables installed in a nuclear power plant. Gamma rays irradiated SiR sheets for various periods at temperatures of 145 and 185 °C, and the resultant changes were analyzed by examining complex permittivity spectra and surface potential decay characteristics. Three different processes, namely, instantaneous polarization, electrode polarization due to the accumulation of ions to form double charge layers at dielectric/electrode interfaces, and DC conduction caused by directional hopping of ions, contribute to the complex permittivity. By fitting the spectra to theoretical equations, we can obtain the dielectric constant at high frequencies, concentration and diffusion coefficient of ions and DC conductivity for the pristine and degraded samples. The instantaneous polarization becomes active with an increase of dose and ageing temperature. The thermal expansion coefficient estimated from the temperature dependence of dielectric constant at high frequencies becomes smaller with an increase in dose, which is in good agreement with the experimental results of the swelling ratio. Additionally, trap distributions are calculated from surface potential decay measurements and analyzed to explain the variation in conductivity. Trap energy increases firstly, and then decreases with an increase in dose, leading to a similar change in DC conductivity. It is concluded that generations of both oxidative products and mobile ions, as well as the occurrence of chain scission and crosslinking are simultaneously induced by gamma rays.

Single-walled carbon nanotube-loaded doxorubicin and Gd-DTPA for targeted drug delivery and magnetic resonance imaging.

An aspargine-glycine-arginine (NGR) peptide modified single-walled carbon nanotubes (SWCNTs) system, developed by a simple non-covalent approach, could be loaded with the anticancer drug doxorubicin (DOX) and magnetic resonance imaging (MRI) contrast agent gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA). This DOX- and Gd-DTPA-loaded NGR functionalized SWCNTs (DOX/NGR-SWCNTs/Gd-DPTA) retained both cytotoxicity of DOX and MRI contrast effect of Gd-DPTA. This drug delivery system showed excellent stability in physiological solutions. This DOX/NGR-SWCNTs/Gd-DPTA system could accumulate in tumors and enter into tumor cells, which facilitated combination chemotherapy with diagnosis of tumor in one system. An excellent in vitro anti-tumor effect was shown in MCF-7 cells treated by DOX/NGR-SWCNTs/Gd-DPTA, compared with DOX solution, DOX/SWCNTs and DOX/SWCNTs/Gd-DPTA. In vivo data of DOX/NGR-SWCNTs/Gd-DPTA group in tumor-bearing mice further confirmed that this system performed much higher tumor targeting capacity and anti-tumor efficacy than other control groups.