Cycling Research Articles

Vibration exposure on cobbles sectors during ParisRoubaix

Background: Paris-Roubaix is a unique and singular race of UCI World Tour. Compared to other “classic races”, the difficulty of the route is increased by the mechanical vibrations encountered during many cobbles sectors. These ones represent ~20% of the total distance to be covered (~250 km). They are classified by the organizers according to their length and the cobble’s characteristics from “easy” (two stars) to “very hard” (five stars). Previous studies measured vibration exposure at cyclist’s hand on one single cobbles sector [1] and for whole body on short urban road path [2]. Thus, the vibration exposure of cyclists during a whole race that includes many cobbles sectors remain unknown. Purpose: The aim of this study was to measure the mechanical vibrations encountered on cobbles sectors of a “classic race” according to the norms used in the working world (ISO 2631-1, 1997; ISO 5349-1, -2, 2001).  Methods: One male cyclist (1.80 m; 68 kg) participated in the 139-km route of the “ParisRoubaix Challenge 2015” a . This race included 15 of the 27 cobbles sectors of the official professional course. Two tri-axial accelerometers (HiKoB Fox, HiKoB, Villeurbanne, France) were firmly mounted on the stem and the seatpost of the subject’s bike (Roubaix Expert carbon, Specialized, USA; tyre pressure set at 5.0 bar). According to the norms and previous results [2], only vertical accelerations (normal to the stem and longitudinal along the seatpost, sampled at 1350 Hz) were used to assess the effective values of vibrations. Cycling speed and heart rate (HR) were measured continuously with a GPS device (Garmin Egde 800, Garmin, Kansas City, USA). Power output (PO) and pedalling cadence (PC) were measured every 1-s with a PowerTap Hub SL+ (CycleOps, USA) and pedalling data were logged on the GPS device. For each sector, the effective value of the acceleration (RMS, m.s -2 ) and the vibration dose value (VDV, m.s -1.75 ) were computed from the raw acceleration subtracted by its mean value (freeing it from the orientation of the sensor). Pearson’s regressions were performed to analyse the relationship between RMS and cycling speed during cobbles sectors.  Results: The total length covered for the 15 cobbles sectors analysed was 28.1 km at a mean speed of 21.8 km.h -1 . Distance, speed, HR, PC, and PO during cobbles sectors were distributed from 0.51 to 3.69 km, 19.1 to 27.8 km.h -1 , 122 to 155 bpm, 79 to 87 rpm, and 167 to 235 W, respectively. Figure 1 shows that vibration dose value measured at stem (hand) and seatpost (whole body) seems to increase with the cobbles sectors difficulty. The RMS value increased significantly (p < 0,001) with the mean speed (Figure 2). According to the European guidelines (2002), the time periods needed to reach the value of exposure which triggers the action (TEAV, s) and the limit exposure value (TELV, s) were for whole body: 10 ± 3 s and 52 ± 14 s, respectively; and for hands: 153 ± 29 s and 610 ± 116 s.  Discussion and Conclusion: According to RMS and VDV values, vibration exposure is much higher at hands than at the cyclist’s seat, regardless the speed and the cobbles sector difficulty. VDV measured at seatpost are at least two times higher than values reported previously in road biking on urban path combining asphalt and pavement [2]. Limit exposure values are reached within minutes that is much fewer than the total time spent on cobblestones by professional riders during Paris-Roubaix race (~90 min). The question remains about the cyclist’s adaptations to this traumatic vibration exposure by adopting an appropriate posture or by increasing muscle work for damping vibrations.

Acute sleep disruption: does it limit performance but heighten immunity?

Introduction: Alterations to sleep patterns in athletes are commonly reported prior to competition and during travel to events (Juliff et al., 2015; Erlacher et al., 2011). When sleep is completely deprived decrements in performance and increased perceptions of effort are reported (Temesi et al., 2013; Oliver et al., 2009). Circulating levels of white blood cells are reported to alter during periods of sleep deprivation (Kerkhofs et al., 2007) or remain unchanged (Costa et al., 2010). Sleep disruption is perhaps more commonly experienced in athletic populations which could alter biological rhythms, immune responses and performance.  Purpose: To examine the effect of disrupted sleep on exercise-induced physiological and immunological parameters. Methodology: Ten healthy male cyclists performed 1h of cycling at a fixed power output on an indoor cycle ergometer following either a night of DS (woken every hour of the night over an 8h period) or a night of undisrupted sleep (US) (left undisrupted for an 8h period). Heart rate (HR), perceived rate of exertion and sleep parameters were all recorded. Blood was collected before, immediately after and 1h after exercise completion. White blood cells and their subtypes were enumerated.  Results: Statistically significant differences between US and DS trials were observed for the mean heart rate during the exercise bout (t (9) = 4.80, p < 0.01) and rate of perceived exertion (RPE) (t (9) = 3.86, p < 0.01). Repeated measures ANOVA revealed a significant trial (US/DS) * time (minutes) interaction with heart rate (F (12/108) = 5.94; p < 0.01) and RPE (F (12/108) = 3.8; p < 0.05), Bonferroni corrected post hoc analysis between trials is illustrated in figure 1 & 2 below. Repeated measures ANOVA yielded a significant trial (US/ DS) x interaction with time (pre, post, 1 h post) for total lymphocytes (F (2/18) = 5.84, p < 0.05, r = 0.5) suggesting lymphocytes were significantly altered with exercise depending on whether the participants had endured a night of DS or US. Bonferroni post hoc analysis revealed this was driven by the larger increase in lymphocytes at the post time point following the DS trial (t (9) = 2.88, p < 0.01, r = 0.69). CD8+ T-cells similarly demonstrated a trial x time interaction (F (2/18) = 4.12; p < 0.03, r = 0.43) with a larger increase in cell number apparent during the DS trial, post hoc analysis revealed this was driven by a larger increase in CD8+ T-cells immediately post exercise during the DS trial (t (9) = 2.69, p < 0.05, r = 0.67). There was no time x trial interaction observed for CD4+ T-cells, NK cells or I³I´ T-cells between US and DS conditions  Conclusions: Our findings indicate that short-term changes to sleep architecture lower heart rate during fixed intensity exercise while the perception of effort was increased, suggesting that acute sleep deprivation reduced cardio-respiratory function which could lead to performance decrements during endurance exercise. Sleep disruption augmented lymphocyte redeployment from the peripheral blood compartment which may ‘prime’ the system during exposure to short-term sleep disruption.

Role of dermal stem cells in hair follicle cycling

The hair follicle is composed of the epidermal (epithelial) and dermal (mesenchymal) compartments, whose interaction plays an important role in the morphogenesis and growth of hair follicles, and is also a key factor for successful reconstruction of hair follicles. Generally, dermal cells are considered as inducers, and epithelial cells as responders during the process of hair formation. There are hair follicle dermal stem cells (HFDSCs) in the dermal sheath and hair papilla, which belong to adult stem cells, and are characterized by slow periodicity, undifferentiation, self-renewal and strong proliferative ability in vitro. HFDSCs in the dermal sheath show a relatively long life, and can survive several hair follicle cycles to reconstitute the dermal sheath. In the anagen phase of hair follicle cycles, stem cells in the dermal sheath generate new cells for the hair papilla. In the catagen phase, dermal stem cell progenies move out of the hair papilla or die. HFDSCs are of great significance for reconstruction and repair of hair follicles after occurrence of injuries and diseases. Key words: Hair follicle; Dermis; Stem cells; Biological processes; Hair diseases

Tropical Mountain Wetlands

Water scarcity is an alarming problem in densely populated tropics and subtropics that are located in hydrologically sensitive zones. Mountains will play an increasingly important role in these regions, particularly in sustaining water availability in the future. They are often termed as 'water towers', important for water cycling, and many major rivers of the world originate here. Mountains also support a number of distinctive wetlands such as riparian areas, marshes, peatlands and wet meadows, over short distances as the hydrological characteristics change at small spatial scales. Additionally, varied landforms, biogeochemical environment, slope, elevation and climate gradient also influence mountain wetland characteristics.

The application of PDCA cycling management in preventing falls of hospitalized patients with high risk of falling down in hepatology department

Objective To explore the effect of PDCA cycling management in reducing the incidence of falling for hospitalized patients with high risk of falling down in hepatology department and in nursing management for preventing falls. Methods Hospitalized patients with high risk of falling down in hepatology department were investiged by PDCA program to find out the common causes for falling and relevant preventive measures were formulated, including setting up the management team of fall, preparing the relevant health education materials, posting warning labels in the ward area, screening risks of falling for hospitalized patients, informing the patients with high risk of falling and their families and signing consent form, and conducting targeted health education for patients with high risk of falling.And relevant preventing measures were taken and the effects were evaluated. Results Number of patients who fell among the hospitalized patients with high risk of falling down in hepatology department was decreased from 17 in 2014 to 1 in 2015 after the implementation of PDCA cycling management and the risk rate was only 0.064 ‰. The patients' safety were guaranteed. Conclusions PDCA cycling management can reduce the risk of falling for hospitalized patients with high risk of falling down in hepatology department. Key words: PDCA cycling management; Hospitalized patients with liver disease; High-risk of fall

Similar mitochondrial signaling responses to a single bout of continuous or small-sided-games-based exercise in sedentary men.

This study assessed the mitochondrial related signaling responses to a single bout of noncontact, modified football (touch rugby), played as small-sided games (SSG), or cycling (CYC) exercise in sedentary, obese, middle-aged men. In a randomized, crossover design, nine middle-aged, sedentary, obese men completed two, 40-min exercise conditions (CYC and SSG) separated by a 21-day recovery period. Heart rate (HR) and ratings of perceived exertion (RPE) were collected during each bout. Needle biopsies from the vastus lateralis muscle were collected at rest and 30 and 240 min postexercise for analysis of protein content and phosphorylation (PGC-1α, SIRT1, p53, p53Ser15, AMPK, AMPKThr172, CAMKII, CAMKIIThr286, p38MAPK, and p38MAPKThr180/Tyr182) and mRNA expression (PGC-1α, p53, NRF1, NRF2, Tfam, and cytochrome c). A main effect of time effect for both conditions was evident for HR, RPE, and blood lactate (P < 0.05), with no condition by time interaction (P > 0.05). Both conditions increased PGC1-α protein and mRNA expression at 240 min (P < 0.05). AMPKThr172 increased 30 min post CYC (P < 0.05), with no change in SSG (P > 0.05). CYC increased p53 protein content at 240 min to a greater extent than SSG (P < 0.05). mRNA expression of NRF2 decreased in both conditions (P < 0.05). No condition by time interactions were evident for mRNA expression of Tfam, NRF1, cytochrome c, and p53. The similar PGC-1α response between intensity-matched conditions suggests both conditions are of similar benefit for stimulating mitochondrial biogenesis. Differences between conditions regarding fluctuation in exercise intensity and type of muscle contraction may explain the increase of p53 and AMPK within CYC and not SSG (noncontact, modified football).

High-frequency oscillatory ventilation for adult patients with acute respiratory distress syndrome

Background As a new kind of ventilatory mode, high-frequency oscillatory ventilation(HFOV) is characterized by the rapid delivery of small tidal volumes cycling and high mean airway pressure. It has been successfully used in adults with the acute respiratory distress syndrome(ARDS). It has been shown that HFOV has advantages over conventional mechanical ventilation(CMV) in improving oxygenation and reducing the incidence of ventilator associated lung injury(VILI). However, the effect of HFOV on mortality still needs to be characterized. Objective To summarize the trials evaluating HFOV in adults with ARDS and reveal both the strengths and weaknesses of HFOV. Content HFOV is associated with significant improvement in oxygenation and prevention of VILI, however, not associated with reduction of mortality. Further researches are needed to identify optimal patient selection, timing, ventilator settings, and the role of combining HFOV with other interventions. Trend Further researches and explorations are needed to define the role of HFOV in adult ARDS. Key words: High-frequency oscillatory ventilation; Acute respiratory distress syndrome; Adult; Mortality

Clinical effects of built-in 4F ureteral catheter combined with 200μm holmium yag laser fiber in treating upper urinary tract stone

Objectives To explore the clinical effects of built-in 4F ureteral catheter combined with 200μm holmium yag laser fiber in treating upper urinary tract stone. Methods 46 patients with upper urinary tract stone in our hospital from September 2014 to April 2015 were managed with built-in 4F ureteral catheter combined with 200μm holmium yag laser fiber. During the operation, the 4F ureteral catheter played an important role in the water cycling for clear field and lower pressure of ureteral lumen. Results In this study, the lithotripsy rate was 95.66%, the operation time was (36.5±4.8)min, time of hospital stays was (2.9±0.4)d, the duration of blood urine postoperative was (1.8±0.3)d. The ureteral lumen pressure of pre-rubble, stone obstruction lifting, pro-rubble and finished lithotripsy was (25.6±1.2)mmHg, (51.6±4.3)mmHg, (28.7±2.8)mmHg, (12.4±3.5)mmHg, respectively. There was no ureteral injury, fever and bleeding in all cases. Conclusions Built-in 4F ureteral catheter with 200μm holmium yag laser fiber in treating upper ureteral calculi was safe and reliable, affordable and easy to operate. Key words: Ureteral Calculi; Lasers, Solid-State; Lithotripsy, Laser

The detection and clinical significance of homocysteine in patients with coronary atherosclerotic heart disease

In recent years, high plasma homocysteine (HHcy) as an independent risk factor for coronary atherosclerotic heart disease (CHD) has been widely received clinical attention. Some detection methods and clinical research for patients with CHD are constantly developing. Enzymatic cycling assay, the most commonly used method at present, represents important application value in the aspects of disease occurrence, severity prediction and therapeutic monitoring for CHD.(Chin J Lab Med, 2016, 39: 726-728) Key words: Coronary disease; Homocysteine; Severity of illness index

Evaluation of the Cyclus cycle ergometer and the Stages power meter for measurement of power output in cycling

The purpose of the present study was to evaluate two commercially available power meters: the Cyclus ergometer (CYC) and the Stages power meter (STA) in comparison to a highly-validated power meter (SRM). Ten trained cyclists (mean ± SD; age 24 ± 8 y, body mass 69.7 ± 7.3 kg) performed an incremental exercise test to exhaustion (GXT), 2 x 10 sec sprints (10ST) and a 1-min test (1minTT) on a bicycle attached to a cycle ergometer (CYC). The bicycle was also fitted with the SRM cranks and the STA power meter. Power output (W) for the CYC and STA for each test was compared to the SRM to determine the validity of the devices. The coefficient of variation (CV) for the STA vs SRM during the GXT was 2.4 ±1.1% (±90% CL) and 2.3 ±0.9% for the CYC vs SRM.  For the 1minTT, the STA vs SRM had a CV of 3.4 ±1.6% and 3.0% ±1.6% for CYC vs SRM. Comparison between power meters during the 10ST showed a CV of 18.2 ±1.6% for STA vs SRM and 13.7 ±1.6% for CYC vs SRM. In summary, both the CYC and STA are practical, easy to use devices and exhibit an acceptable level of agreement during low ( ~650W) power outputs.

A Comparison of the Accuracy and Reliability of the Wahoo KICKR and SRM Power Meter

The Wahoo KICKR cycling trainer is a new direct-drive electromagnetically braked bike-trainer that allows cyclists to use their own bicycles as ergometer. It is purported to provide ±3% accuracy in power, despite costing considerably less than other cycling ergometers. The purpose of this study was to assess the accuracy and reliability of several KICKR units against the more established SRM power meter using a first-principles based dynamic calibration rig (CALRIG).Five KICKRs and one SRM unit were assessed by a CALRIG-driven incremental test. Following a 15 min warm-up and ‘calibration’ as per manufacturer instructions, power was increased (starting at 50 W) by 50 W every 2 min up to 400 W. Each unit was tested twice non-consecutively, in random order. Data was recorded at 1 Hz, with the last 10 s of each stage being averaged for analysis. The mean error (%) and coefficient of determination (R 2 ) versus CALRIG; as well as the change in mean error and Typical Error of Measurement (TEM) (expressed as a % coefficient of variation) between trials was calculated for each device.The mean error across all KICKR units was -1.5% (range: -3.1% to 0.0%) compared to -1.6% reported by the SRM. R 2 >0.999 was found for all KICKR units and SRM compared to the CALRIG. The mean TEM for the KICKRs was 1.5% (range: 1.1% to 1.9%), whereas the SRM reported 0.7%. For test-retest reproducibility, two KICKRs had statistically significant changes in mean error, with an average 1.3% change across all KICKRs. Comparatively, the SRM reported a 0.4% change between trials. The Wahoo KICKR trainer measures power to a similar level of accuracy to the more reputable SRM power meter during an incremental exercise test. Although not as reproducible, the KICKR still demonstrates an acceptable level of reliability for assessing cycling performance.

Effects of grazing intensity and grazing exclusion on litter decomposition in the temperate steppe of Nei Mongol, China

Aims Grazing intensity and grazing exclusion affect ecosystem carbon cycling by changing the plant community and soil micro-environment in grassland ecosystems. The aims of this study were: 1) to determine the effects of grazing intensity and grazing exclusion on litter decomposition in the temperate grasslands of Nei Mongol; 2) to compare the difference between above-ground and below-ground litter decomposition; 3) to identify the effects of precipitation on litter production and decomposition. Methods We measured litter production, quality, decomposition rates and soil nutrient contents during the growing season in 2011 and 2012 in four plots, i.e. light grazing, heavy grazing, light grazing exclusion and heavy grazing exclusion. Quadrate surveys and litter bags were used to measure litter production and decomposition rates. All data were analyzed with ANOVA and Pearson’s correlation procedures in SPSS. Important findings Litter production and decomposition rates differed greatly among four plots. During the two years of our study, above-ground litter production and decomposition in heavy-grazing plots were faster than those in light-grazing plots. In the dry year, below-ground litter production and decomposition in light-grazing plots were faster than those in heavy-grazing plots, which is opposite to the findings in the wet year. Short-term grazing exclusion could promote litter production, and the exclusion of light-grazing could increase litter decomposition and nutrient cycling. In contrast, heavy-grazing exclusion decreased litter decomposition. Thus, grazing exclusion is beneficial to the restoration of the light-grazing grasslands, and more human management measures 杨丽丽等: 内蒙古温带草原不同放牧强度和围栏封育对凋落物分解的影响 749 doi: 10.17521/cjpe.2016.0051 are needed during the restoration of heavy-grazing grasslands. Precipitation increased litter production and decomposition, and below-ground litter was more vulnerable to the inter-annual change of precipitation than above-ground litter. Compared to the light-grazing grasslands, heavy-grazing grasslands had higher sensitivity to precipitation. The above-ground litter decomposition was strongly positively correlated with the litter N content (R = 0.489, p < 0.01) and strongly negatively correlated with the soil total N content (R = 0.450, p < 0.01), but it was not significantly correlated with C:N and lignin:N. Below-ground litter decomposition was negatively correlated with the litter C (R = 0.263, p < 0.01), C:N (R = 0.349, p < 0.01) and cellulose content (R = 0.460, p < 0.01). Our results will provide a theoretical basis for ecosystem restoration and the research of carbon cycling.

August 2016 - This Month in JoVE: Sampling in Suspension Feeders, Staining Three-Dimensional Skin, Spasms in the Heart Vasculature, and Emotional Reponses to Beverages

Here's a look at what's coming up in the August 2016 issue of JoVE: The Journal of Visualized Experiments. In JoVE Environment, we take a look at aquatic organisms that feed on particles floating in the water around them, aptly named suspension feeders. Most studies involving these animals require their housing in laboratory settings, which can disrupt behavior. So Morganti et al.present a method to build an apparatus-modified for scuba diving-that can be used to collect water inhaled or exhaled by suspension feeders in their natural environments. Samples gathered with this method can then be analyzed, helping us better understand the roles these organisms play within their ecosystems, for example in nutrient cycling. Researchers are also exploring the roles different cells perform in their environments-such as the organs they might help comprise. As a result, tissue samples are being processed in new ways that maintain their three-dimensional structure. This month, JoVE Biology highlights one such staining protocol developed by Liang et al., which allows for the visualization of proteins within individual cells present in full-thickness mouse skin. Due to its use of whole mount samples, this effective procedure can help elucidate interactions between the different layers of this important regenerative organ, including those that may contribute to skin cancer. Disease diagnosis can rely on analyses of protein expression, as well as direct observations of a patient and their physiological responses. For example, angina-or chest pain-is a topic of interest in JoVE Medicine, and may be a symptom of vasomotor disorders, which include spasms of the vasculature supplying blood to the heart. Here, Ong et al. describe a method to diagnose such disorders that relies on the sequential administration of increasing concentrations of a neurotransmitter, assessing a patient's electrocardiograms, and looking for any constrictions in the coronary arteries. This method provides a convenient protocol that can be implemented in clinical settings, with limited risk to a patient. Finally, we switch gears in JoVE Behavior, where an analysis of individuals' emotional responses to different types of beverages is featured. How a person reacts to a drink can be distinguished-in part-by facial muscle movements, which can be recorded using video. In this study, Crist et al.present a standardized protocol to collect such data, and interpret it using Automated Facial Expression Analysis software. Importantly, this method can be extended to other applications, like interpreting how an individual responds to product packaging. You've just had a sneak peek of the Aug 2016 issue of JoVE. Visit the website to see the full-length articles, plus many more, in JoVE: The Journal of Visualized Experiments.

Orthodontist Fleur is a cycling champion

Orthodontist Fleur is a cycling champion

Addition of strength training to off-road cyclists training. A pilot study

This study investigated the effects of adding a traditional strength training approach (endurance-strength = ES) during the pre-season versus a non-traditional approach where strength training is further maintained throughout the season (maximal-strength = MS), on aerobic and anaerobic parameters of off-road cyclists. Eleven off-road cyclists were divided into two groups. The ES group (n=6) performed during the first 8 weeks endurance-strength training, while the MS group (n=5) performed maximal-strength training, both together with their usual endurance training. During the following 8 weeks, only MS group maintained 1 session of strength training per week. 1RM, VO 2 max, Maximal aerobic power (Wmax), Power at 4-mmol·L -1 (LT 4.0 ), Peak Power (PP), Mean Power (MP), Power best 5s (PB5), Power last 5s (PL5) and Fatigue Index (FI) were assessed. Results showed that there were significant ( P < 0.05) increases for MS group in PP (+ 4.8%) from PRE to MID, in 1RM (+ 15.8%) from PRE to POST, while in the ES group there was a decrease in 1RM (- 16.1%), PL5 (-4.3%) with an increase in FI (+ 9.5) from MID to POST. Effect size calculations showed small and moderate improvements in PP (+ 3.6%), MP (+ 2.8%), PB5 (+ 4.3%) from PRE to POST for MS group, while ES group showed a small improvement in VO 2 max (+ 4.1%), LT 4.0 (+ 4.3%) and PB5 (+ 2.7%) from PRE to MID, and a small decrease between MID to POST in Wmax (- 4.1%) and MP (- 2.6%). These results suggest that by including a non-traditional strength training approach it is possible to maintain aerobic levels and possibly increase anaerobic parameters throughout the off-road cycling season

The Cycling City Project: infrastructure strategies and technologies for sustainable mobility. The case of Copenhagen

Il progetto delle infrastrutture, e quindi il progetto del paesaggio urbano, costruiscono un sistema di relazioni e dinamiche multi-scalari, insite nella definizione di spazio collettivo. La progettualita espressa dal caso di Copenhagen esprime una innovativa idea di citta, che privilegia la multidisciplinarita, la partecipazione, la gestione razionale delle risorse economiche ed energetiche. Tali strategie possono rappresentare gli elementi comuni a diversi contesti, incorporando gli indirizzi di sostenibilita sociale e ambientale di uno spazio urbano viene concepito come campo d’interazione tra diversificate esperienze culturali e identitarie di cui sono portatori i suoi abitanti.

Bicycling-related accidents and factors contributing to injury

Objective: This study was conducted to find the epidemiological characteristics of bicycling-related maxillofacial fractures in a defined population, and identify factors contributing to injury. Methodology: A prospective study was carried out involving patients presenting with maxillofacial fractures sustained in bicycling-related accidents. Results: Between 908 of all cycling accidents attending for medical treatment, 122 patients (13% of all cycling accidents) were admitted with facial fractures between 2007 and 2014. Male and female ratio was 2.6:1, and the mean age was 29.4 years (standard deviation: 12.8, range: 12-79 years). Causes of injury included collisions (63%) and accidental falls (37%). The fracture patterns seen were mandibular (49%), zygomatic (32%), orbital (13%), nasal (7%), maxillary (2%), and frontal (2%). Condylar fractures were the most common of the mandibular fractures (63%). The most frequently observed concomitant lesions were orthopedic injuries. Conclusions: Bicycling-related maxillofacial injuries are common and therefore important to identify in order to design a sustainable transport system and for units that provide assistance to traffic accident victims. Missed diagnosis or delayed treatment can lead to facial deformities and functional problems. Wearing protective helmets and the improvement of the helmets design is one aspect that would be of interest for the prevention of injuries. Keywords: Cycling; bicycle-related trauma; maxillofacial fractures; risk factors; helmets. DOI: http://dx.doi.org/10.4995/CIT2016.2016.3718

Methodological application of Location of service Public Bike. Service MUyBICI of Murcia

The use of non-motorized means of transport such as the bicycle, brings many benefits to the user and for the city in terms of costs and health for the first and decreased environmental pollution for the city. To find the optimal location for placement of the different parties to public bike, aims to attract the usual user and potential, have the feasibility of switching modes without any restrictions, while generating the ability to balance the demands users towards sustainable modes of transport, with special attention to cycling and public bike loan. The implementation of this methodology is performed in the municipality of Murcia (Spain) due to the opening of its public bicycle system MUyBICI which will have 60 benches, with a total of 1,200 posts anchor and put into circulation 600 public bicycles. As selection criteria to be considered for the optimal location of the beds, the existing network of bike paths were considered, roads used by all users of the public highway, a description of travel and a database information with different land uses and socioeconomic data transport areas. In this paper an analysis model and application for optimal design of banking locations for Murcia MUyBICI service occurs. Specifically, they define what are the best locations to attract a larger number of users, in order to achieve a change in the percentage of the modal split of the municipality, increasing the number of users MUyBICI service. This work comes under the direction of the Bicycle Office of Murcia, part of the ALEM (Local Agency for Energy and Environment) service under the Department of Environment of the City of Murcia. DOI: http://dx.doi.org/10.4995/CIT2016.2016.4090

DETECTING THE GAZING ATTENTION POINTS OF YOUNG AND ELDERLY CYCLISTS.

This study analyzed the perceived attention represented by "gazing" points of cyclists to expose a latent accidental factor hidden in cyclist behaviour. Eleven elderly people and 23 young people equipped with an eye camera participated in the study. From the camera images, the objects viewed by the cyclists were analyzed. A main road and a community road were used in the experiment. The objects viewed by the cyclists were categorized into nine items that would be indirectly related to the cause of bicycle traffic accidents: gates and porches, parking lots, signals, alleys, other bicycles on the road, pedestrians, signs and painted symbols on the road, schoolyards and houses, and other items. The results of the study indicated that many elderly cyclists always confirmed their safety at alley intersections along both main and community roads, whereas many young people were not so dutiful. The results for unsafe gazing behavior such as looking at a schoolyard or house while cycling were the same for the two groups in that most individuals did not look away from the road while cycling along the main and community roads. Dissimilar results, especially those for alley intersections, resulted from young people not paying due attention to objects, suggesting that such gazing behaviour could be strongly related to traffic accidents involving a bicycle.

微结构和应力比对Ti-6Al-4V高周和超高周疲劳行为的影响 *

Titanium alloys have been widely used as superior engineering materials because of their high specific strength, high temperature resistance and high corrosion resistance. In their engineering applications such as used in aircraft engines, titanium alloys may experience even 10(10) fatigue cycles. Recently, faceted crack initiation was observed in high-cycle fatigue (HCF) and very-high-cycle fatigue (VHCF) regimes of titanium alloys, which resulted in a sharp decrease in fatigue strength. Therefore, the HCF and VHCF of titanium alloys have both scientific significance and engineering requirement. In this work, the effects of microstructure and stress ratio (R) on HCF and VHCF of a Ti-6Al-4V alloy have been investigated. Fatigue tests were conducted on a rotating-bending fatigue machine and an ultrasonic fatigue machine. All the fatigue fracture surfaces were observed by SEM. The results show that the HCF and VHCF behaviors of the fully-equiaxed and the bimodal Ti-6Al-4V alloy are similar. The observations of fracture surface indicate that two crack initiation mechanisms prevail, i.e. slip mechanism and cleavage mechanism. With the increase of stress ratio, the crack initiation mechanism switches from slip to cleavage. The S-N curves present the single-line type or the bilinear type. For the cases of rotating-bending and ultrasonic axial cycling with R= -1.0, -0.5 and 0.5, the S-N curves are single-line type corresponding to the slip mechanism or cleavage mechanism. For the cases of R= -0.1 and 0.1, the S-N curves are bilinear type corresponding to both slip and cleavage mechanisms. A model based on fatigue life and fatigue limit is proposed to describe the competition between the two mechanisms, which is in agreement with the experimental results.