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991.
992.
A new class of radio frequency (RF) coils for magnetic resonance (MR) imaging and spectroscopy is introduced. The coils consist of two loop-gap resonators of equal diameters positioned along a common axis. They are tuned to the mode in which the current in the two loops flows in opposite directions. These coils are "decoupled" from a uniform excitation field of arbitrary orientation (including circularly polarized fields) by intrinsic decoupling and by means of back-to-back fast recovery diodes. Measurements made with the coils and a phantom saline tank indicate that the signal-to-noise ratio obtainable with these coils is almost identical to that obtained with single loops. Imaging of several anatomic areas, including knee, wrist, and shoulder, has been performed with a 1.5-T MR system that uses circularly polarized RF. A small series of patients with torn rotator cuffs underwent imaging. Difficulties in establishing the diagnosis with MR imaging because of anatomic complexity are illustrated. The value of pulse sequences with long repetition times to increase the signal intensity of fluid in the joint is shown.  相似文献   
993.
In recent years, assistive technologies have gained acceptance as tools for supporting chronically ill patients in achieving improvements in physical activity. However, various healthcare and sociological studies show contradicting results regarding the physical and social impact of using such devices. This paper explores real-time user appropriation of an assistive monitoring/tracking device, the pedometer, in a healthcare intervention, with a particular focus on the technology identities users attribute to the pedometer. The study site was a rehabilitation programme at a local Danish health centre supporting patients with chronic obstructive pulmonary disease. As part of this empirical study, six focus-group interviews were conducted with patients before and after they used pedometers. The analysis of respondents’ accounts shows that monitoring devices become part of users’ complex socio-technical ensembles in which the use of the device and its tracking of activity is constantly negotiated through experimentation with type and frequency of use; interpretation of knowledge and experience gained via the device; and negotiation of expectations, wellbeing, and the value of quantified knowledge for the management of chronic illness. On the basis of these findings the paper brings together and advances sociological scholarship on chronic illness, embodiment, the quantified self and technology adoption.  相似文献   
994.
Medicine, Health Care and Philosophy - The Covid-19 pandemic creates an unprecedented threatening situation worldwide with an urgent need for critical reflection and new knowledge production, but...  相似文献   
995.
There has been a growing interest in the gastrointestinal system and its significance for autism spectrum disorder (ASD), including the significance of adopting a gluten-free and casein-free (GFCF) diet. The objective was to investigate beneficial and safety of a GFCF diet among children with a diagnosis of ASD. We performed a systematic literature search in Medline, Embase, Cinahl, and the Cochrane Library up to January 2020 for existing systematic reviews and individual randomized controlled trials (RCTs). Studies were included if they investigated a GFCF diet compared to a regular diet in children aged 3 to 17 years diagnosed with ASD, with or without comorbidities. The quality of the identified existing reviews was assessed using A Measurement Tool to Assess Systematic Reviews (AMSTAR). The risk of bias in RCTs was assessed using the Cochrane Risk of Bias Tool, and overall quality of evidence was evaluated using Grades of Recommendation, Assessment, Development, and Evaluation (GRADE). We identified six relevant RCTs, which included 143 participants. The results from a random effect model showed no effect of a GFCF diet on clinician-reported autism core symptoms (standardized mean difference (SMD) −0.31 (95% Cl. −0.89, 0.27)), parent-reported functional level (mean difference (MD) 0.61 (95% Cl −5.92, 7.14)) or behavioral difficulties (MD 0.80 (95% Cl −6.56, 10.16)). On the contrary, a GFCF diet might trigger gastrointestinal adverse effects (relative risk (RR) 2.33 (95% Cl 0.69, 7.90)). The quality of evidence ranged from low to very low due to serious risk of bias, serious risk of inconsistency, and serious risk of imprecision. Clinical implications of the present findings may be careful consideration of introducing a GFCF diet to children with ASD. However, the limitations of the current literature hinder the possibility of drawing any solid conclusion, and more high-quality RCTs are needed. The protocol is registered at the Danish Health Authority website.  相似文献   
996.
997.
The past decades have seen contradictory research results on the health benefits and risks of menopausal hormone therapy (HT). In particular, long-term associations with overall cancer incidence and the potential interplay with other lifestyle factors remain undetermined. In a population-based prospective cohort, 29,152 women aged 50–64 years at entry (1993–1997) were followed through 2013 for incidence of cancer (99% complete follow-up). Cox’ proportional hazards models were used to estimate cancer incidence according to baseline HT alone and in combination with lifestyle factors including alcohol intake, BMI, physical activity, diet, and smoking. Among 5484 women diagnosed with cancer, baseline HT was associated with an overall higher risk of cancer (HR 1.28; 95%CI, 1.21–1.36)—in particular, a higher risk of breast (HR 1.77; 95%CI, 1.61–1.95), ovarian (HR 1.68; 95%CI, 1.26–2.26), and endometrial (HR 1.86; 95%CI, 1.45–2.37) cancer. Combination with other lifestyle risk factors largely displayed additive associations. The risk of colorectal cancer was significantly lower (HR 0.79; 95%CI, 0.66–0.95). However, in the interaction analysis, only “healthy” subgroups of women using HT had a lower risk of colorectal cancer. With an overall higher risk of cancer among women on HT, this study underlined the importance of considering all female cancer risks in menopausal treatment guidelines. The largely additive associations between HT and the investigated lifestyle factors support the notion that high levels of hormones in itself play an important etiological role in female reproductive cancers, whereas the possible protective impact in colorectal cancer might be limited to women with an otherwise healthy lifestyle.  相似文献   
998.
OBJECTIVES: Estimate pregnancy, abortion, and birth rates for 1990 to 1995 for all teens, sexually experienced teens, and sexually active teens. DESISN: Retrospective analysis of national data on pregnancies, abortions, and births. Participants. US women aged 15 to 19 years. OUTCOME MEASURES: Annual pregnancy, abortion, and birth rates for 1990 to 1995 for women aged 15 to 19 years, with and without adjustments for sexual experience (ever had intercourse), and sexual activity (had intercourse within last 3 months). RESULTS: Approximately 40% of women aged 15 to 19 years were sexually active in 1995. Teen pregnancy rates were constant from 1990 to 1991. From 1991 to 1995, the annual pregnancy rate for women aged 15 to 19 years decreased by 13% to 83.6 per 1000. The percentage of teen pregnancies that ended in induced abortions decreased yearly; thus, the abortion rate decreased more than the birth rate (21% vs 9%). From 1988 to 1995, the proportion of sexually experienced teens decreased nonsignificantly. CONCLUSIONS: After a 9% rise from 1985 to 1990, teen pregnancy rates reached a turning point in 1991 and are now declining. Physicians should counsel their adolescent patients about responsible sexual behavior, including abstinence and proper use of regular and emergency contraception.  相似文献   
999.
The optimal management of prolonged second stage of labour remains a confused area of thought and action. This confusion is particularly evident when epidural analgesia is also being used. A review of the literature indicates that prolonged duration of the second stage, i.e. from full dilation of the cervix until delivery, with or without epidural analgesia, has little adverse effect on perinatal outcome. More attention should be paid to the expulsive phase of the second stage and greater efforts made to reduce unnecessary interventions.  相似文献   
1000.
The declining prevalence of left-handed individuals with increasing age has led to two main avenues of hypotheses; the association is due either (1) to a birth cohort effect and/or an age effect caused by a switch to right-handedness with advancing age or (2) to mortality selection that reduces survival in left-handed individuals, or both. It is uncertain whether a cohort or age effect can explain the decline in age-related prevalence, and conflicting evidence exists in favor of the mortality hypothesis. We compared mortality in a subgroup of 118 opposite-handed twin pairs by counting in how many instances the right-handed twin died first. There was no evidence of differential survival between right-handed and non-right-handed individuals in the entire 1900-1910 cohort. With respect to the number of right-handed twins who died first, there was no material disadvantage among those who were not right-handed. In 60% (95% confidence interval = 49.0-71.5%) of dizygotic pairs, the right-handed twins died first. In 50% of monozygotic pairs, right-handed twins died first. The prevalence of not being right-handed was higher among males (9.2%) than females (6.5%); there was a similar frequency of non-right-handedness in monozygotic (8.0%) and dizygotic (7.8%) twins. We did not find evidence of excess mortality among non-right-handed adult twins in this follow-up study.  相似文献   
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