Quantitative magnetic resonance spectroscopy at 3T based on the principle of reciprocity

Quantification of magnetic resonance spectroscopy signals using the phantom replacement method requires an adequate correction of differences between the acquisition of the reference signal in the phantom and the measurement in vivo. Applying the principle of reciprocity, sensitivity differences can be corrected at low field strength by measuring the RF transmitter gain needed to obtain a certain flip angle in the measured volume. However, at higher field strength the transmit sensitivity may vary from the reception sensitivity, which leads to wrongly estimated concentrations. To address this issue, a quantification approach based on the principle of reciprocity for use at 3T is proposed and validated thoroughly. In this approach, the RF transmitter gain is determined automatically using a volume‐selective power optimization and complemented with information from relative reception sensitivity maps derived from contrast‐minimized images to correct differences in transmission and reception sensitivity. In this way, a reliable measure of the local sensitivity was obtained. The proposed method is used to derive in vivo concentrations of brain metabolites and tissue water in two studies with different coil sets in a total of 40 healthy volunteers. Resulting molar concentrations are compared with results using internal water referencing (IWR) and Electric REference To access In vivo Concentrations (ERETIC). With the proposed method, changes in coil loading and regional sensitivity due to B₁ inhomogeneities are successfully corrected, as demonstrated in phantom and in vivo measurements. For the tissue water content, coefficients of variation between 2% and 3.5% were obtained (0.6–1.4% in a single subject). The coefficients of variation of the three major metabolites ranged from 3.4–14.5%. In general, the derived concentrations agree well with values estimated with IWR. Hence, the presented method is a valuable alternative for IWR, without the need for additional hardware such as ERETIC and with potential advantages in diseased tissue.     

Relative validity of dietary patterns during pregnancy assessed with a food frequency questionnaire

Abstract

This study aimed to assess the relative validity of maternal dietary patterns derived from a semi-quantitative food frequency questionnaire (FFQ). A total of 162 pregnant women aged 19–40-years-old were enrolled from the Universiti Sains Malaysia (USM) Birth Cohort Study in year 2010 and 2011. The FFQ was compared with three 24-h dietary recalls (DRs). Two major dietary patterns were derived from the principle component analysis which are labeled as Healthy and Less-Healthy patterns. The Pearson correlation coefficients between FFQ and DRs for Healthy and Less-Healthy patterns were 0.59 and 0.63, respectively. At least 45% of the participants were correctly classified into the same third from the FFQ and DR for both dietary patterns. The weighted kappa showed moderate agreement for Healthy pattern while good agreement for Less-Healthy pattern between these two dietary assessment methods. Our results indicate reasonable validity of the dietary patterns identified from the FFQ in pregnant women.     

Cholera‐schistosomiasis coinfection dynamics

The present work investigates the coinfection dynamics of the cholera and schistosomiasis diseases. The steady states of the model are examined. We obtain results for the model in detail and present the stability results whenever the basic reproduction number is less than unity ( ). For each submodel, the existence of backward bifurcation is presented and for the coinfection model. Furthermore, we formulate an optimal control problem with an appropriate set of control variables. The optimal control problem and the associated results are derived and discussed. The optimal control problem and the suggested controls are utilized to obtain optimal control characterizations. Numerical results are presented by choosing various optimal control strategies for the early elimination of both infections from the population. It is suggested that appropriate uses and application to the population could significantly reduce the infection. Therefore, based on our findings, we suggest to the public health department that the only possible cost‐effective strategy for the elimination of schistosomiasis and cholera coinfection is the combination of both diseases' preventive measures and the treatment of schistosomiasis.     

Night-time braces for treatment of Adolescent Idiopathic Scoliosis

Purpose. This review article aims at providing an update on the basic science and clinical information underlying the use of nocturnal braces for adolescent idiopathic scoliosis.

Method. The National Institutes of Health online medical database (Medline) was used to retrieve all articles pertinent to clinical research on night-time bracing; data were also collected from manufacturing companies. Additional information was obtained from literature on pathomechanics of scoliosis.

Results. The cardinal feature of night-time braces lays in their ability to hypercorrect the scoliotic curvature, thereby eliminating the asymmetric water accumulation that occurs in the apical and adjacent intervertebral discs. Previously wedge-shaped discs resume a nearly cylindrical configuration, thus restoring a close-to-normal force application to the endplates through the Hueter-Volkmann principle and preventing curve progression. The two night-time braces mostly used hypercorrect the spine through different mechanisms.

Conclusions. On the basis of clinical results available, night-time braces constitute an attractive option for single-major lumbar/thoracolumbar curves not exceeding 35° in magnitude. Multi-center, randomized studies using strict criteria set forth by the Scoliosis Research Society (SRS) and the Society on Spinal Orthopaedic and Rehabilitation Treatment (SOSORT) are needed to better define the role of nocturnal bracing in the conservative treatment of adolescent idiopathic scoliosis.     

The Interplay of Pain-Related Self-Efficacy and Fear on Functional Outcomes Among Youth With Headache

Pain-related self-efficacy and pain-related fear have been proposed as opposing predictors of pain-related functional outcomes in youth with chronic pain. Self-efficacy is a potential resiliency factor that can mitigate the influence that pain-related fear has on outcomes in youth with chronic pain. Drawing from theoretical assertions tested among adults with chronic pain, this study aimed to determine whether pain-related self-efficacy mediates the adverse influence of pain-related fear on functional outcomes in a sample of youth with chronic headache. In a cross-sectional design of 199 youth with headache, self-efficacy was strongly associated with fear, disability, school impairment, and depressive symptoms. Pain intensity and self-efficacy were only modestly related, indicating that level of pain has less influence on one's confidence functioning with pain. Self-efficacy partially mediated relationships between pain-related fear and both functional disability and school functioning but did not mediate the relationship between pain-related fear and depressive symptoms. These results suggest that confidence in the ability to function despite pain and fear avoidance each uniquely contributes to pain-related outcomes in youth with chronic headache. These results further suggest that treatment for chronic headache in youth must focus not only on decreasing pain-related fear but also on enhancing a patient's pain-related self-efficacy.PerspectivePain-related self-efficacy is an important resiliency factor impacting the influence of pain-related fear on functional disability and school functioning in youth with headache. Enhancing self-efficacy may be a key mechanism for improving behavioral outcomes. Clinicians can reduce pain-related fear and enhance pain-related self-efficacy through interventions that encourage accomplishment and self-confidence.     

调脂治疗是收益还是风险？

诸多的研究结果证明了他汀类药物调脂治疗对降低心血管事件具有一定的有效性和安全性。然而,也有研究结果显示了强化调脂治疗的风险性。为尽可能发挥调脂治疗的功效又避免或减少用药的风险,可遵循生活方式干预、常规剂量给药、全面调脂治疗、个体化治疗和综合治疗等原则。     

Parental Mediation Of Children's Internet Use In Different European Countries

Given that various childrearing cultures exist in Europe, as confirmed by analysis of the 1999/2000 European Values Survey (Halman, 2001), the present study aimed to identify and explain cross-cultural similarities and differences in strategies of parental mediation of children's Internet use. The study also sought to identify which parental mediation strategies may protect children against experiencing content risks online in general and in various childrearing cultures in particular. Parental mediation strategies and content online risk were indexed on the basis of data from 18 European countries from the Eurobarometer 2005. Findings show that all parents favor social mediation of the internet for children over strategies based on technical solutions. Favoring restrictive (by time or content) to non-restrictive mediation depends on a country's value orientation in childrearing. Analyses showed that each parental strategy has the potential to reduce the probability of children's experience of content risk online. However, the extent to which particular parental mediation strategies are protective differs across European childrearing cultures.     

竹筏原理在Pilon骨折中的应用

目的 总结利用竹筏原理,采用T 形锁定板和苜蓿钢板治疗Pilon 骨折的经验.方法 36 例Pilon骨折患者按Ruedi-Allgower 分型,达Ⅱ型19 例,Ⅲ型17 例,均采用切开复位,L 形锁定板或苜蓿钢板内固定术.结果 治疗后,临床疗效优良率80.6%,其中Ⅱ型达84.2%,Ⅲ型达76.5%.结论 利用竹筏原理,采用L 形锁定板或苜蓿钢板治疗Pilon 骨折,具有固定稳定性可靠,有利于骨折愈合和早期关节负重的优点,其远期疗效有待于进一步讨论.     

实施新医院财会制度的困惑与思考

从医院财务管理和会计实务出发,分析了执行新医院财务、会计制度的疑点和难点,以期为完善医院财会制度建设提供一些参考。     

The relationship between weight change and daytime sleepiness: the Sleep Heart Health Study

ObjectiveThrough a causal framework, we aim to assess the association between weight change and daytime sleepiness, and the role of obstructive sleep apnoea (OSA) in this relationship.MethodsFrom the Sleep Heart Health Study, we selected individuals who were: (1) 40–64 years old, with (2) body mass index (BMI) ≥18.5 kg/m², (3) no history of stroke, treatment for OSA, and tracheostomy at baseline. We used multiple linear regression to assess the relationship between five-year weight change and daytime sleepiness (assessed through Epworth Sleepiness Scale (ESS)) at five years, adjusting for daytime sleepiness, demographics, diabetes, subjective sleep duration, sleep disturbance, smoking status, weight, and use of antidepressants and benzodiazepines at baseline, in those with complete data (N = 1468). We further assessed the potential mediating role of OSA in this relationship.ResultsAt baseline, the study participants were on average 55 years old, 46% males, with mean BMI 28 kg/m²; and 25% had ESS>10. ESS at five years worsened by 0.36 units (95% confidence interval (CI) 0.12–0.61, p = 0.004) with every 10-kg weight gain. When stratified by sex, this relationship was only found in women (0.55, 95% CI 0.25–0.86, p < 0.001; p-interaction = 0.02). Approximately one-fifth of the relationship between weight change and daytime sleepiness was mediated by severity of OSA at five years.ConclusionWeight gain has a detrimental effect on daytime sleepiness, mostly through pathways other than OSA. This study provides further evidence and understanding of the relationship between obesity and excessive daytime sleepiness.