ABSTRACT
Cable-stayed bridges have been commonly used on high-speed railways. The design, construction, and maintenance of cable-stayed bridges necessitate an accurate assessment of the cable temperature field. However, the temperature fields of cables have not been well established. Therefore, this research aims to investigate the distribution of the temperature field, the time variability of temperatures, and the representative value of temperature actions in stayed cables. A cable segment experiment, spanning over one year, is conducted near the bridge site. Based on the monitoring temperatures and meteorological data, the distribution of the temperature field is studied, and the time variability of cable temperatures is investigated. The findings show that the temperature distribution is generally uniform along the cross-section without a significant temperature gradient, while the amplitudes of the annual cycle variation and daily cycle variation in temperatures are significant. To accurately determine the temperature deformation of a cable, it is necessary to consider both the daily temperature fluctuations and the annual cycle of uniform temperatures. Then, using the gradient boosted regression trees method, the relationship between the cable temperature and multiple environmental variables is explored, and representative cable uniform temperatures for design are obtained by the extreme value analysis. The presented data and results provide a good basis for the operation and maintenance of in-service long-span cable-stayed bridges.
Subject(s)
Temperature , Regression AnalysisABSTRACT
Background: Urinary biopyrrin (UBP) is an oxidative metabolite formed from the reaction of bilirubin with reactive oxygen species. Previous studies have explored the relationship between UBP levels and certain diseases or pregnancy. However, UBP levels in healthy nonpregnant women have not been well examined. We aimed to clarify the representative value of UBP in healthy nonpregnant women and explore its relationship with menstrual cycles and concomitant symptoms. Methods: We included healthy, nonpregnant Japanese women aged 20-39 years with normal body mass index and menstrual cycle. In total, 1260 urine samples collected during 43 menstrual cycles of 36 women were analyzed to determine the representative values and reference intervals of UBP levels. The correlation between daily UBP levels and the order of the day was explored, and median UBP levels of 5-day clusters were compared using Friedman and Mann-Whitney U tests. These analyses were also conducted in women with concomitant symptoms during the menstrual cycle. Results: The median UBP level in all samples was 0.2291 (reference: 0.0102-2.9335) µmol/gCr. There was no significant relationship between the median UBP level and menstrual cycle, regardless of the presence of self-manageable symptoms during or before menstruation. Conclusions: The representative UBP value and its reference interval can serve as standards for comparison with other populations. Our findings suggest that the UBP level may be an objective oxidative stress indicator that is less sensitive to menstrual cycle and concomitant symptoms. UBP levels in healthy nonpregnant women could be assessed regardless of the menstrual cycle and concomitant symptoms.
ABSTRACT
Resting-state neural oscillations are used as biomarkers for functional diseases such as dementia, epilepsy, and stroke. However, accurate interpretation of clinical outcomes requires the identification and minimisation of potential confounding factors. While several studies have indicated that the menstrual cycle also alters brain activity, most of these studies were based on visual inspection rather than objective quantitative measures. In the present study, we aimed to clarify the effect of the menstrual cycle on spontaneous neural oscillations based on quantitative magnetoencephalography (MEG) parameters. Resting-state MEG activity was recorded from 25 healthy women with normal menstrual cycles. For each woman, resting-state brain activity was acquired twice using MEG: once during their menstrual period (MP) and once outside of this period (OP). Our results indicated that the median frequency and peak alpha frequency of the power spectrum were low, whereas Shannon spectral entropy was high, during the MP. Theta intensity within the right temporal cortex and right limbic system was significantly lower during the MP than during the OP. High gamma intensity in the left parietal cortex was also significantly lower during the MP than during the OP. Similar differences were also observed in the parietal and occipital regions between the proliferative (the late part of the follicular phase) and secretory phases (luteal phase). Our findings suggest that the menstrual cycle should be considered to ensure accurate interpretation of functional neuroimaging in clinical practice.
ABSTRACT
BACKGROUND: Nerve conduction study is an objective and quantitative diagnostic method for the diagnosis and follow-up study of polyneuropathy. Sometimes it is hard to interpret the nerve conduction study, because there are many segmental variables to test and uneven distribution of abnormalities in polyneuropathy. And there can be some interpersonal differences in the interpreting the results. It is obvious that one objective and quantitative value that represents the many segmental variables is helpful for the clinical interpretation and follow?up of polyneuropathy. METHODS: We evaluated 242 normal subjects and 71 patients with demyelinating polyneuropathy to find out a standardized representative value, distinguishing patients from normal subjects. The standardized representative value was made by combination of the some standardized segmental variables which showed marked differences between two groups. We evaluated the clinical usefulness of this value by comparing the sequential changes of this value with the clinical course. RESULTS: Statistically significant differences were present in each segmental value of the nerve conduction study between the groups of patients and normal persons. The diagnostic sensitivity of the segmental value was in range of 25.7%-81.8% in case of 2SD criteria. The diagnostic sensitivity of each functional standardized value - average of the segmental standardized values of same nature - was in range of 54.1%-89.9% in case of 2SD criteria. Using 3SD criteria the sensitivity was reduced to 20.9%-81.1%, more in sensory and mixed nerve than motor nerve. By combination of these functional standardized values, the diagnostic sensitivity could increase up to 79.1%-93.2% on 3SD criteria. CONCLUSION: The best combination which represents the NCV study is the average of the motor nerve terminal latency, the motor nerve conduction velocity, and the ratio of conduction block with 93.2% sensitivity and 100% specificity. This representative value well reflects the clinical course of patient in follow-up studies.
