Safety Effects of Horizontal Curve Reliability Index

Recent advancements in analytical processes have used probabilistic approaches to examine the efficacy of the point mass model (and other Green Book models) to develop reliability-based approaches for geometric design. However, there has been minimal research establishing the link between reliability measures and substantive safety (expressed through crash frequency). The objective of this paper is to use empirical data supporting the calculation of reliability index for existing horizontal curves and to estimate the relationship between reliability index and crash frequency. Other horizontal curve-related characteristics that may have an impact on crash frequency on horizontal curves for rural two-lane highways and rural freeway facilities are controlled for in the evaluation. The safety analysis showed that the wet pavement reliability index was significantly associated with crash frequency for total curve-related crashes, single-vehicle run-off-road crashes, rollover crashes, truck-related crashes, and weather-related crashes. The relationship was strongest for the reliability index in its continuous form, meaning that the effect is continuous across the range of wet pavement reliability that was observed.

THU0403 THE EFFECT OF SPINAL STABILIZATION EXERCISES ON SPINAL CURVES DIAGNOSED WITH ANKYLOSING SPONDYLITIS

Background:Postural deformities can cause changes in spinal curvatures patients with ankylosing spondylitis. In these patients, preventive and therapeutic approaches are needed for spinal deformities (1). Positive effects of the spinal stabilization exercises are manifested in reducing pain, maintaining mobility, improving posture, increasing aerobic capacity and improving quality of life (2).Objectives:The aim of this study is to investigate the effect of stabilization exercises on spinal curvatures in s ankylosing spondylitis patients.Methods:Twenty-eight ankylosing spondylitis patients (25 females, 3 males) with a mean age of 30.87 ± 9.13 years were included in the stabilization exercises program. The patients performed spinal stabilization exercises two days a week for six weeks. Stabilization training includes training of deep muscles providing diaphragmatic breathing, neutral spine position control training and local motor control, and motor control training of global muscles, dynamic stabilization exercises and strengthening training. Thoracic kyphosis and lumbar lordosis curvature of patients in an upright position were evaluated with Spinal Mouse (SM) device before and after therapy program. The SM device is a reliable, valid, safe, quick method that can be used in the clinics and researches of the adults with no side effects.Results:At the end of 6 weeks of treatment, there was a decrease in the total curvature degree of the thoracic vertebrae in the sagittal axis (p=0.026). No significant difference was found in the lumbal region (p= 0.109).Table 1.Differences of Total Curve DegreesPre-Exercises ProgramMean±SDPost-ExercisesProgramMean±SDzpThoracal Total Curve Degrees43.50±8.1142.57±7.70-2.232*0.026Lumbal Total Curve Degrees-26.42±8.46-23.77±7.15-1.6040.109*p<0.05, SD: Standart DeviationConclusion:Stabilization exercises are effective in reducing thoracic kyphosis in patients with ankylosing spondylitis patients. The use of these exercises in treatment programs will contribute significantly to improving spinal alignment and preventing postural deformities.References:[1]Grazio, S., Grubišić, F., & Brnić, V. (2019). Rehabilitation of patients with spondyloarthritis: a narrative review.Medicinski Glasnik,16(2).[2]Gunay, S. M., Keser, I., & Bicer, Z. T. (2018). The effects of balance and postural stability exercises on spa based rehabilitation programme in patients with ankylosing spondylitis.Journal of back and musculoskeletal rehabilitation,31(2), 337-346.Disclosure of Interests: :None declared

Structural design and mechanical properties analysis of bamboo-wood cross-laminated timber

To explore the overall mechanical properties of bamboo-wood composite cross-laminated timber (BCLT), a simulation model of BCLT mechanical behavior based on the solid element was established using the finite element software ABAQUS. The actual four-point bending experiment was compared and analyzed with the finite element numerical simulation. The total curve error coefficient of the BCLT specimen at 18-mm displacement was 0.2988 while the interval was 0.5 mm. The error coefficient was 0.0178 when the maximum load was reached, and the minimum error coefficient was 0.0015 at 12 mm of displacement. Analysis of the influence of material parameters, meshing density, and material arrangement on the final stress distribution indicate that the difference in the elastic parameters of the material greatly influence the final stress distribution, and the arrangement and combination of materials also have an effect on the overall mechanical properties of the BCLT board. The combination CLT1-2-1 (i.e., the upper and lower layers of the bamboo are Arrangement 1 and the hemlock is Arrangement 2) have a maximum load of 57682 Ν and a maximum stress of 103.9 MPa.

Elasticity Solutions to Nonbuckling Serpentine Ribbons

Stretchable electronics have found wide applications in bio-mimetic and bio-integrated electronics attributing to their softness, stretchability, and conformability. Although conventional electronic materials are intrinsically stiff and brittle, silicon and metal membranes can be patterned into in-plane serpentine ribbons for enhanced stretchability and compliance. While freestanding thin serpentine ribbons may easily buckle out-of-plane, thick serpentine ribbons may remain unbuckled upon stretching. Curved beam (CB) theory has been applied to analytically solve the strain field and the stiffness of freestanding, nonbuckling serpentine ribbons. While being able to fully capture the strain and stiffness of narrow serpentines, the theory cannot provide accurate solutions to serpentine ribbons whose widths are comparable to the arc radius. Here we report elasticity solutions to accurately capture nonbuckling, wide serpentine ribbons. We have demonstrated that weak boundary conditions are sufficient for solving Airy stress functions except when the serpentine’s total curve length approaches the ribbon width. Slightly modified weak boundary conditions are proposed to resolve this difficulty. Final elasticity solutions are fully validated by finite element models (FEM) and are compared with results obtained by the curved beam theory. When the serpentine ribbons are embedded in polymer matrices, their stretchability may be compromised due to the fact that the matrix can constrain the in-plane rotation of the serpentine. Comparison between the analytical solutions for freestanding serpentines and the FEM solutions for matrix-embedded serpentines reveals that matrix constraint remains trivial until the matrix modulus approaches that of the serpentine ribbon.

Functional imaging using DCE-US: Which parameter for the early evaluation of antiangiogenetic therapies?

3524 Background: The early evaluation of anti-angiogenic treatments is a challenge in oncology. Functional imaging methods based on the measure of tumoral vascularization have been developed using different modalities (CT, MRI, US). We analyzed the response in four studies using different targeted treatments with dynamic contrast enhanced-ultrasonography (DCE-US). Seven parameters characterizing tumoral perfusion were estimated. The objective of the study was to determine which parameter is the most appropriate to confirm earlier the efficacy of treatments. Methods: A total of 823 DCE-US were performed in 117 patients included in 4 following studies (multikinase inhibitor targeting angiogenic-receptor with a cytotoxic or thyrosine-kinase inhibitor targeted angiogenic-receptor and C-kit or monoclonal antibody anti-VEGFR). Each DCE-US was performed using contrast agent (Sonovue, Bracco) with perfusion and quantification softwares (Toshiba) from raw linear data with a high temporal resolution: 4 frames per second during 3 minutes. Seven quantitative parameters of perfusion were estimated: peak intensity (PI) and area under the total curve (AUC), area under the wash-in (AUWI), area under the wash-out (AUWO), time to peak intensity, mean transit time (MTT), wash-in slope. DCE-US were performed before treatment and after D3, D 8, 15, 21 (according each study design) and every 2 months. Patients were classified in good responders and bad responders according the response (RECIST on CT-scan) after 2 cycles or 2 months. Results: Among the 7 parameters, 2 parameters related to the blood volume studies (AUC and AUWO) were always earlier significantly modified (p = 0.04 to p = 0.004). One was never modified: MTT. For the 4 others, it's depending of each study. Conclusions: DCE-US appears as a sensitive tool to evaluate tumoral response to anti-angiogenic drugs. Functional parameters related to the blood volume are more pertinent and represent a key add value to early evaluation of these therapies studies. No significant financial relationships to disclose.

Use of extensigraph in the examination of wheat flours

The extensograph is widely used in quality control and research laboratories studying wheat flour quality. The most commonly used measurements include Rm, the maximum resistance (maximum height of the curve); R5 the resistance at a constant extension of 5 cm; E, extensibility (total curve length); Rm/E, the ratio of maximum resistance to extension; and A, the area under curve. The extensograph has proved useful in the classification and assessment of flours on the physical dough properties. Another important application is its use in wheat breeding programs. Furthermore, extensograph is an excellent tool to study the effects of a wide range of ingredients on dough properties of wheat flour (like oxidants, enzymes, salt and additives), and it can also be used measure the changes during the frozen storage. In the present study we provide a review of the scientific literature concerning the possible applications of the extensograph.

C14 studies in carbohydrate metabolism: glucose pool size and rate of turnover in the normal rat

The curve of decline of specific activity after an intravenous injection of C14 glucose in rats consists of at least three components. Because extrapolation of the third portion of the curve (subsequent to 1 hr.) gives a value for glucose space which appears to be spuriously high, the rate of glucose disposal calculated therefrom is also likely to be in error. Assumption that the total curve is formed from the composite effect of mixing, recycling via nonglucose carbon, and irreversible glucose disposal permits construction of a compatible physiological model. Glucose pool size and rate of irreversible disposal calculated by mathematical treatment of this model may then be approximated. Calculations indicate that glucose space in the rat is approximately 20% of body weight. Irreversible disposal (oxidation plus synthesis to fat, etc.) is in the vicinity of 0.6 mg/min. for fasted rats and 1 mg/min. for postabsorptive rats. Total turnover time of plasma glucose is approximately 2–3 minutes. Combined glucogenesis and gluconeogenesis seem to proceed more rapidly in the postabsorptive state than during fasting.