Notes

Cytotoxicity of chitosans with some other acetylation degrees and molecular weight load upon vesica carcinoma tissue.
Respiration-induced tumor or organ positional changes can impact the accuracy of external beam radiotherapy. Motion management strategies are used to account for these changes during treatment. The authors report on the development, testing, and first-in-human evaluation of an electronic 4D (e4D) MR-compatible ultrasound probe that was designed for hands-free operation in a MR and linear accelerator (LINAC) environment.

Ultrasound components were evaluated for MR compatibility. Electromagnetic interference (EMI) shielding was used to enclose the entire probe and a factory-fabricated cable shielded with copper braids was integrated into the probe. A series of simultaneous ultrasound and MR scans were acquired and analyzed in five healthy volunteers.

The ultrasound probe led to minor susceptibility artifacts in the MR images immediately proximal to the ultrasound probe at a depth of <10mm. Ultrasound and MR-based motion traces that were derived by tracking the salient motion of endogenous target structures in the superior-inferior (SI) direction demonstrated good concordance (Pearson correlation coefficients of 0.95-0.98) between the ultrasound and MRI datasets.

We have demonstrated that our hands-free, e4D probe can acquire ultrasound images during a MR acquisition at frame rates of approximately 4 frames per second (fps) without impacting either the MR or ultrasound image quality. This use of this technology for interventional procedures (e.g. biopsies and drug delivery) and motion compensation during imaging are also being explored.
We have demonstrated that our hands-free, e4D probe can acquire ultrasound images during a MR acquisition at frame rates of approximately 4 frames per second (fps) without impacting either the MR or ultrasound image quality. This use of this technology for interventional procedures (e.g. biopsies and drug delivery) and motion compensation during imaging are also being explored.Roadway lighting is used to ensure nighttime safety and security for multimodal road users. However, the absence of reliable quantitative analyses of the safety effects of roadway lighting photometric characteristics prevents accurate assessment of street lighting maintenance and retrofitting projects. This study aimed to investigate the relationship between nighttime crash risk and two critical photometric criteria, i.e., average lighting level and uniformity. To achieve this goal, high-resolution horizontal illuminance data were collected in Florida for 300 + center-miles from 2011 to 2014. Based on the data, a matched case-control study was conducted to address two major issues existing in previous studies (1) the confounding effects of illuminance standard deviation on illuminance mean and (2) spatially-unrelated extreme values for ratio-based uniformity. By eliminating the confounding effects through a random matching strategy (one case, a segment with nighttime crashes, to one control, a segment without nighttime crashes at 1,046 strata), this study successfully isolated the negative effects of the standard deviation and developed more significant crash modification factors (CMFs) for average lighting levels 0.679 for increasing the average lighting level from [0 fc, 0.5 fc] to (0.5 fc, 1.0 fc] and 0.581 for increasing the average lighting from [0 fc, 0.5 fc] to higher than 1.0 fc. Additionally, a CMF of 1.391 for a max-min ratio greater than 10 was identified by controlling the segment length at a short uniform unit (1,200 ft). The developed CMFs overcame the underestimation issue in previous studies and are implementable in current street lighting design and safety management.The time-to-collision (TTC) index and its extended variants have been widely utilized to assess rear-end collision risks, but the characteristics of the time-series data have not been fully explored, especially for the transition from safe to risky conditions. This study proposes a novel approach in rear-end collision risk analysis based on the concept of transition durations. The vehicle trajectory data were extracted and the TTC index was used to identify risky and safe conditions. Three important transition durations are defined and their rationalities for evaluating rear-end collision risks are examined by developing random-parameters accelerated failure time (AFT) survival models. Furthermore, a typical case from real trajectory data is taken to discuss the limitations of using TTC and its variants, and the advantage of the proposed transition durations. The results of random-parameters AFT models reveal contributing factors affecting the length of three durations and demonstrate the rationality of transition durations in rear-end collision risks analysis. It is indicated that the proposed method outperforms TTC and its variants in evaluating rear-end collision risks, because it could not only provide the information of time point but also the variation of time-series data.Perceptual markings on roads are verified with short-term effectiveness for accident prevention. However, the long-term performance of them is seldomly investigated, which unintentionally impedes its more widely recognition and application as a low-cost and readily achievable countermeasure. Also, the previous perceptual markings were only tested for speed reduction effect, little is known concerning their influence on headway adjustment. Given this, in this study, we investigated the short-, medium-, and long-term performance of the reverse linear perspective markings (RLPMs) on driving behaviors and safety benefits in car-following. The RLPMs were a form of markings pattern that can produce reverse linear perspective visual information on the lane and lead to distance underestimation. The RLPMs were permanently installed on a straight and a curve segment of a freeway in China, and the naturalistic vehicle flow data one day, four months, one year, two years, and three years after the installation of the RLPMh (DRAC). The findings of this study suggest the RLPMs could be an especially applaudable form of perceptual markings as they are relatively effective in the long-term and are multifunctional in intervening speed, distance, headway, and crash risk. LJI308 This study also emphasizes the challenge of more field tests and observations on the long-term performance of the perceptual markings, and the thorough considerations of the visual perception mechanism behind the markings to achieve an alternative solution to the long-term issue.
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