Time-Dependent Seismic Performance of Coastal Bridges Reinforced with Hybrid FRP and Steel Bars

To increase the durability and seismic resilience of coastal bridges, a hybrid reinforced concrete (HRC) bridge that incorporates both glass fiber-reinforced polymer (GFRP) bars and steel bars is proposed. The time-dependent seismic performance of the HRC bridge is comprehensively investigated at three levels, namely the material, bridge column and bridge structure levels. First, the decrease of tensile strength of GFRP bars over time is analyzed based on the Arrhenius theory, and corrosion initiation time and performance deterioration of steel bars are determined by Fick’s second law and an empirical formula. Second, an efficient finite element modeling method for aging HRC bridge columns is proposed. Simulation of the compression/tension behavior and the fracture failure of the GFRP bar is described. Hysteretic analysis is further conducted to investigate the time-dependent energy dissipation, ductility, residual displacement, bearing capacity and post-yield stiffness ratio. Meanwhile, comparisons of HRC bridge columns to reinforced concrete (RC) references are provided. Third, the seismic demand and damage evolution of deteriorated HRC bridge structures are investigated through dynamic time-history analysis. The results indicate that the corrosion-resistant GFRP bars contribute to improving the bearing capacity and to reducing the residual displacement of the HRC bridge. With an increase in service time, the seismic damage to the bridge column, abutment and expansion bearing increases, but the damage to fixed bearing decreases. Research results presented herein show that the HRC bridge is a promising alternative structure scheme in the marine environment.     

Alcohol retail sales licenses and sexually transmitted infections in Texas counties, 2008-2015

Background: Research suggests that reduced retail alcohol outlet density may be associated with lower prevalence of HIV and other sexually transmitted infections (STIs). On-premise sale of alcohol for immediate consumption is theorized as increasing social interactions that can lead to sexual encounters. Objective: We examined associations between on- and off-premise retail alcohol sales licenses and number of newly diagnosed HIV and STI cases in Texas counties. Methods: Retail alcohol sales license data were obtained from the Texas Alcoholic Beverage Commission. HIV and bacterial STI data were obtained from the Texas Department of State Health Services. Associations between retail alcohol sales licenses and STIs were estimated using spatial linear models and Poisson mixed effects models for over-dispersed count data. Results: Adjusting for county-specific confounders, there was no evidence of residual spatial correlation. In Poisson models, each additional on-premise (e.g., bar and restaurant) alcohol license per 10,000 population in a county was associated with a 1.5% increase (95% CI: 0.4%, 2.6%) in the rate of HIV and a 2.4% increase (95% CI: 1.9%, 3.0%) in the rate of bacterial STIs, adjusting for potential confounders. In contrast, number of off-premise licenses (e.g., take-out stores) was inversely associated with the incidence of STI and HIV, although the association with HIV was not statistically significant. Conclusions: This study adds to the limited literature on the association between retail alcohol availability and STIs. Additional research is needed on the role of alcohol availability (and policies affecting availability) in the spread of HIV and other STIs.     

Complete Sella Turcica Bridges Prevalence and Dimensions

Interclinoid ligaments which connect the anterior and posterior clinoid processes comprise a group of intrinsic ligaments of sphenoid bone. The complete sella turcica bridge corresponds to the complete ossification of the interclinoid ligaments. 112 dry human adult skull bones were studied for presence of ossified interclinoid ligaments. Nine skulls (8.04%) showed sella turcica bridges, out of which six were unilateral and three bilateral. The average length of the bridge was 11.67mm. The average width and thickness at the anterior clinoid process was 6.33mm and 4.33mm ; atthe middle of the bridge 3.08mm and 2.66mm; and atthe posterior clinoid process, 4.91 mm and 3.66mm, respectively. Anomalies of sellar region are not very rare and may pose difficulties in interpretation of Magnetic Resonance Imaging or Computed Tomographyforthe radiologist. Thesefindings would also guide the neurosurgeons in planning neurosurgical procedures involving the sellar region.     

Prevalence of and Differences in Salad Bar Implementation in Rural Versus Urban Arizona Schools

Background

Rural children consume more calories per day on average than urban children, and they are less likely to consume fruit. Self-service salad bars have been proposed as an effective approach to better meet the National School Lunch Program’s fruit and vegetable recommendations. No studies have examined how rural and urban schools differ in the implementation of school salad bars.

Design and Evaluation of a New Resin-Filled GFRP Pipe Connection System for Butt Splicing of FRP Bars

Fiber-reinforced polymer (FRP) bars are one of the promising alternatives for steel bars used in concrete structures under corrosion or non-magnetic environments due to the unique physical properties of FRP materials. When compared with steel bars, FRP bars are difficult to be spliced in field application due to their anisotropy and low shear and compressive strengths. In view of this, the paper presents a new non-metallic connection system (i.e., resin-filled glass fiber-reinforced polymer (GFRP) pipe connection system) for the butt splicing of FRP bars. With the proposed connection system and a simplified trilinear interfacial bond-slip model, a set of design formulas were derived based on the requirement that the proposed connection system should provide a load transfer capacity beyond the tensile capacity of the spliced FRP bars (i.e., to fulfill the high tensile strength of FRP materials). Besides, considering the fabrication error-induced load transfer capacity reduction of the connection system in field application, a correction factor was introduced in the paper to compensate for the reduced load transfer capacity by increasing the FRP bar anchorage length. At last, to estimate the effectiveness of the proposed connection system and the derived design formulas, nine specimens were fabricated with a kind of commercially available basalt fiber-reinforced polymer (BFRP) bars and the designed connection system and tested under unidirectional tension to study their tensile performance. With the comparison between the tested and theoretical results, the effectiveness of the proposed connection system and the derived design formulas are verified.     

Structural features of crayfish phasic and tonic neuromuscular terminals

We examined the fine structure of terminals of the phasic and tonic excitatory axon to the crayfish limb extensor muscle. The phasic terminals are known to release 50–100 times more transmitter for a small length of terminal for a single impulse. Phasic terminals labeled with horseradish peroxidase (HRP) were relatively thin and contained a single unbranched mitochondrion; tonic terminals were much thicker, and their varicosities contained several multibranched mitochondria. Tonic terminals devoted a larger proportion of their total volume to mitochondria. The percentage volume of clear synaptic vesicles was slightly higher in phasic axon terminals, but as the tonic axon terminals were fivefold larger in volume, the total synaptic volume is much greater in tonic than phasic terminals. The number of synapses per length of terminal, and the total number of active zones per length of terminal, were greater for tonic terminals, and individual synapses were, on average, slightly larger in surface contact area for tonic terminals. In contrast, individual active zones were, on average, longer in phasic synapses. A higher proportion (50%) of phasic synapses had multiple active zones than was the case for tonic synapses (16%), and pairs of closely spaced active zones were more frequently found on phasic synapses. These findings clearly rule out synapse and active zone number as a factor contributing to higher transmitter output, but suggest that active zone size and synaptic complexity, as evidenced by multiple closely spaced active zones in a single synapse, are likely to play a causal role in the greater transmitter release of the phasic terminal. Even synapse complexity would not be enough to account fully for the large difference in terminal transmitter output, and additional factors may include electrical and biochemical differences. © 1996 Wiley-Liss, Inc.     

Impact of Magnetization on the Evaluation of Reinforced Concrete Structures Using DC Magnetic Methods

The magnetic method is the most promising method that can be used to inspect large areas of reinforced concrete (RC) structures. Magnetization is a crucial process in this method. The paper aims to present the impact of the magnetization method on the results in the detection of reinforced bars (rebars) and the evaluation of concrete cover thickness in reinforced concrete (RC) structures. Three cases (without magnetization, same pole magnetization, and opposite pole magnetization) were considered in the experiments. Results achieved in all the methods are presented and evaluated. Two different sensing elements were used in the measurements: a magneto-optical (MO) sensor and an AMR sensor. The advantages and disadvantages of both mentioned transducers are presented and discussed in the context of a large areas inspection. The new approach involves using various magnetization methods to improve measurement results for complex structures.     

Surgical and Prosthodontic Treatment of a Patient with Significant Trauma to the Middle and Lower Face Secondary to a Gunshot Wound: A Clinical Report

Large defects of dentofacial structures may result from trauma, disease (including neoplasms), and congenital anomalies. The location and size of the defects are related to difficulties that patients report relative to speech, mastication, swallowing, facial esthetics, and self-image. This article reports on the evaluation and treatment of a patient who suffered significant trauma to the lower and mid-face secondary to a gunshot injury. It describes the initial presentation, life-saving procedures, and subsequent bone grafts, implant placement, and prosthetic treatments required to rehabilitate the patient to a condition that closely approximated his preoperative condition. This clinical report confirms that no matter the degree of complexity involved in treating the results of significant facial trauma, successful treatment is dependent on thorough physical and radiographic examinations, development of the appropriate diagnoses, and treatment based on sound prosthodontic and surgical principles.     

School‐Level Practices and Perceptions Associated With Salad Bars in Schools

BACKGROUND

Salad bars are placed in schools to promote fruit and vegetable consumption among students. This study assessed differences in school nutrition practices and perceptions in schools with and without salad bars.

METHODS

Cross‐sectional surveys were completed by school nutrition managers (N = 648) in Arizona schools participating in the National School Lunch Program during 2013–2014. Mixed general estimating equation binomial regressions assessed factors related to having a salad bar after mutually adjusting for clustering within districts, school level, free/reduced rate, and respondents' time in current position.

RESULTS

On average, 61% of schools reported having a salad bar. After adjustment, school nutrition managers were significantly more likely to report having a salad bar if they served lunch by grade level (vs mixed grades), had a full‐service kitchen, and their personal perception of salad bars was positive; schools were less likely to have a salad bar if menu and food service decisions were made at the school level.

CONCLUSIONS

Several school‐level nutrition practices and perceptions were associated with having a salad bar in schools. Enhancement of these factors may facilitate having salad bars in schools.

     

颌间固位钉和牙弓夹板在颌骨骨折治疗中的临床应用

目的比较颌间固位钉和牙弓夹板两种牵引方法在颌骨骨折牵引固定中的临床疗效。方法把48例有咬合紊乱症状的颌骨骨折患者随机分成2组,每组24人,研究组用颌间固位钉植入上下颌骨,对照组用牙弓夹板结扎固定在上下牙列上,2组均采用弹力皮圈在术中牵引辅助复位或在术后牵引调整咬合关系,所有患者均接受了骨折切开复位及小型钛板＋螺纹钉固定骨折。检查并记录2组的平均操作时间,术后咬合关系的恢复程度,牙周损害程度,口腔卫生状况,询问患者主观感受,给予统计学分析,得出结论并进行临床疗效判定。结果研究组平均操作时间明显短于对照组;研究组患者的牙周损害程度明显轻于对照组;研究组患者的口腔卫生状况也明显好于对照组;颌间固位钉牵引复位大大减少了患者的副损害和痛苦;从主观舒适度方面,患者更能接受颌间固位钉牵引复位法;在牙列基本完整的前提下,两者在咬合关系的恢复方面无明显差异。结论颌间固位钉较牙弓夹板牵引复位或辅助治疗颌骨骨折是一种快速、简单且有效的方法,值得临床推广使用。