Zircon and rutile are common accessory minerals whose essential structural constituents, Zr, Ti, and Si can replace one another to a limited extent. Here we present the combined results of high ...pressure-temperature experiments and analyses of natural zircons and rutile crystals that reveal systematic changes with temperature in the uptake of Ti in zircon and Zr in rutile. Detailed calibrations of the temperature dependencies are presented as two geothermometers--Ti content of zircon and Zr content of rutile--that may find wide application in crustal petrology. Synthetic zircons were crystallized in the presence of rutile at 1-2 GPa and 1,025-1,450 degrees C from both silicate melts and hydrothermal solutions, and the resulting crystals were analyzed for Ti by electron microprobe (EMP). To augment and extend the experimental results, zircons hosted by five natural rocks of well-constrained but diverse origin (0.7-3 GPa; 580-1,070 degrees C) were analyzed for Ti, in most cases by ion microprobe (IMP). The combined experimental and natural results define a log-linear dependence of equilibrium Ti content (expressed in ppm by weight) upon reciprocal temperature: (formula omitted)In a strategy similar to that used for zircon, rutile crystals were grown in the presence of zircon and quartz (or hydrous silicic melt) at 1-1.4 GPa and 67-1,450 degrees C and analyzed for Zr by EMP. The experimental results were complemented by EMP analyses of rutile grains from six natural rocks of diverse origin spanning 0.35-3 GPa and 470-1,070 degrees C. The concentration of Zr (ppm by weight) in the synthetic and natural rutiles also varies in log-linear fashion with T -1: (formula omitted) The zircon and rutile calibrations are consistent with one another across both the synthetic and natural samples, and are relatively insensitive to changes in pressure, particularly in the case of Ti in zircon. Applied to natural zircons and rutiles of unknown provenance and/or growth conditions, the thermometers have the potential to return temperatures with an estimated uncertainty of +/- 10 degrees or better in the case of zircon and +/- 20 degrees or better in the case of rutile over most of the temperature range of interest (approximately 400-1,000 degrees C). Estimates of relative temperature or changes in temperature (e.g., from zoning profiles in a single mineral grain) made with these thermometers are subject to analytical uncertainty only, which can be better than +/- 5 degrees depending on Ti or Zr concentration (i.e., temperature), and also upon the analytical instrument (e.g., IMP or EMP) and operating conditions.PUBLICATION ABSTRACT
Several studies have reported the
P
–
T
dependencies of Ti-in-quartz solubility, and there is close agreement among three of the four experimental calibrations. New experiments were conducted in the ...present study to identify potential experimental disequilibrium, and to determine which Ti-in-quartz solubility calibration is most accurate. Crystals of quartz, rutile and zircon were grown from SiO
2
-, TiO
2
-, and ZrSiO
4
-saturated aqueous fluids in an initial synthesis experiment at 925 °C and 10 kbar in a piston-cylinder apparatus. A range of quartz crystal sizes was produced in this experiment; both large and small examples were analyzed by electron microprobe to determine whether Ti concentrations are correlated with crystal size. Cathodoluminescence images and EPMA measurements show that intercrystalline and intracrystalline variations in Ti concentrations are remarkably small regardless of crystal size. The average Ti-in-quartz concentration from the synthesis experiment is 392 ± 1 ppmw Ti, which is within 95 % confidence interval of data from the 10 kbar isobar of Wark and Watson (Contrib Mineral Petrol 152:743–754,
2006
) and Thomas et al. (Contrib Mineral Petrol 160:743–759,
2010
). As a cross-check on the Ti-in-quartz calibration, we also measured the concentration of Zr in rutile from the synthesis experiment. The average Zr-in-rutile concentration is 4337 ± 32 ppmw Zr, which is also within the 95 % confidence interval of the Zr-in-rutile solubility calibration of Ferry and Watson (Contrib Mineral Petrol 154:429–437,
2007
). The
P
–
T
dependencies of Ti solubility in quartz and Zr solubility in rutile were applied as a thermobarometer to the experimental sample. The average Ti-in-quartz isopleth calculated from the calibration of Thomas et al. (Contrib Mineral Petrol 160:743–759,
2010
) and the average Zr-in-rutile isopleth calculated from the calibration of Tomkins et al. (J Metamorph Geol 25:703–713,
2007
) cross at 9.5 kbar and 920 °C, which is in excellent agreement with the
P
–
T
conditions of the synthesis experiment. Separates of the high-Ti quartz from the initial synthesis experiment described above were used as starting material in subsequent experiments at 20 kbar, at which pressure the solubility of Ti in quartz is expected to be significantly lower in the recrystallized quartz. These recrystallization experiments were conducted under wet and dry conditions at 925 °C, and under wet conditions at 850 °C. Both wet and dry recrystallization experiments produced polycrystalline quartzites. Rutile occurs as inclusions in quartz, and as individual crystals dispersed along quartz grain boundaries. Quartz that grew during the recrystallization experiments has dark cathodoluminescence indicating substantially lower Ti concentrations. The average Ti concentrations in quartz from the recrystallization experiments are within the 95 % confidence interval of a linear fit to the 20 kbar data of Thomas et al. (Contrib Mineral Petrol 160:743–759,
2010
). Collectively, the results from the synthesis and recrystallization experiments confirm that the Ti-in-quartz concentrations used to calibrate the
P
–
T
dependencies of Ti-in-quartz solubility in Thomas et al.’s (Contrib Mineral Petrol 160:743–759,
2010
) calibration represent the equilibrium concentrations of Ti in quartz.
Vertebroplasty has become a common treatment for painful osteoporotic vertebral fractures, but there is limited evidence to support its use.
We performed a multicenter, randomized, double-blind, ...placebo-controlled trial in which participants with one or two painful osteoporotic vertebral fractures that were of less than 12 months' duration and unhealed, as confirmed by magnetic resonance imaging, were randomly assigned to undergo vertebroplasty or a sham procedure. Participants were stratified according to treatment center, sex, and duration of symptoms (< 6 weeks or > or = 6 weeks). Outcomes were assessed at 1 week and at 1, 3, and 6 months. The primary outcome was overall pain (on a scale of 0 to 10, with 10 being the maximum imaginable pain) at 3 months.
A total of 78 participants were enrolled, and 71 (35 of 38 in the vertebroplasty group and 36 of 40 in the placebo group) completed the 6-month follow-up (91%). Vertebroplasty did not result in a significant advantage in any measured outcome at any time point. There were significant reductions in overall pain in both study groups at each follow-up assessment. At 3 months, the mean (+/-SD) reductions in the score for pain in the vertebroplasty and control groups were 2.6+/-2.9 and 1.9+/-3.3, respectively (adjusted between-group difference, 0.6; 95% confidence interval, -0.7 to 1.8). Similar improvements were seen in both groups with respect to pain at night and at rest, physical functioning, quality of life, and perceived improvement. Seven incident vertebral fractures (three in the vertebroplasty group and four in the placebo group) occurred during the 6-month follow-up period.
We found no beneficial effect of vertebroplasty as compared with a sham procedure in patients with painful osteoporotic vertebral fractures, at 1 week or at 1, 3, or 6 months after treatment. (Australian New Zealand Clinical Trials Registry number, ACTRN012605000079640.)
Recommandations: Les 25 recommandations et les 10 enonces de bonne pratique sont repartis en sections: activite physique, alimentation, evaluation du risque de fracture, instauration du traitement, ...interventions pharmacologiques, duree et sequence du traitement, et monitorage. La prise en charge de l'osteoporose devrait se fonder sur le risque de fracture, etabli au moyen d'une evaluation clinique realisee avec un outil d'evaluation du risque de fracture valide. L'activite physique, l'alimentation et la pharmacotherapie sont des elements essentiels a la strategie de prevention des fractures, qui devraient etre personnalises.
Recruitment of young people for health research by traditional methods has become more expensive and challenging over recent decades. The Internet presents an opportunity for innovative recruitment ...modalities.
To assess the feasibility of recruiting young females using targeted advertising on the social networking site Facebook.
We placed an advertisement on Facebook from May to September 2010, inviting 16- to 25-year-old females from Victoria, Australia, to participate in a health study. Those who clicked on the advertisement were redirected to the study website and were able to express interest by submitting their contact details online. They were contacted by a researcher who assessed eligibility and invited them to complete a health-related survey, which they could do confidentially and securely either at the study site or remotely online.
A total of 551 females responded to the advertisement, of whom 426 agreed to participate, with 278 completing the survey (139 at the study site and 139 remotely). Respondents' age distribution was representative of the target population, while 18- to 25-year-olds were more likely to be enrolled in the study and complete the survey than 16- to 17-year-olds (prevalence ratio=1.37, 95% confidence interval 1.05-1.78, P=.02). The broad geographic distribution (major city, inner regional, and outer regional/remote) and socioeconomic profile of participants matched the target population. Predictors of participation were older age, higher education level, and higher body mass index. Average cost in advertising fees per compliant participant was US $20, making this highly cost effective.
Results demonstrate the potential of using modern information and communication technologies to engage young women in health research and penetrate into nonurban communities. The success of this method has implications for future medical and population research in this and other demographics.
Abstract Denosumab has been shown to reduce new vertebral, nonvertebral, and hip fractures in postmenopausal women with osteoporosis. In subjects who were treatment-naïve or previously treated with ...alendronate, denosumab was associated with greater gains in bone mineral density (BMD) and decreases in bone turnover markers when compared with alendronate-treated subjects. This trial was designed to compare the efficacy and safety of denosumab with risedronate over 12 months in postmenopausal women who transitioned from daily or weekly alendronate treatment and were considered to be suboptimally adherent to therapy. In this randomized, open-label study, postmenopausal women aged ≥ 55 years received denosumab 60 mg subcutaneously every 6 months or risedronate 150 mg orally every month for 12 months. Endpoints included percentage change from baseline in total hip BMD (primary endpoint), femoral neck, and lumbar spine BMD at month 12, and percentage change from baseline in sCTX-1 at months 1 and 6. Safety was also assessed. A total of 870 subjects were randomized (435, risedronate; 435, denosumab) who had a mean (SD) age of 67.7 (6.9) years, mean (SD) BMD T-scores of − 1.6 (0.9), − 1.9 (0.7), and − 2.2 (1.2) at the total hip, femoral neck, and lumbar spine, respectively, and median sCTX-1 of 0.3 ng/mL at baseline. At month 12, denosumab significantly increased BMD compared with risedronate at the total hip (2.0% vs 0.5%), femoral neck (1.4% vs 0%), and lumbar spine (3.4% vs 1.1%; p < 0.0001 at all sites). Denosumab significantly decreased sCTX-1 compared with risedronate at month 1 (median change from baseline of − 78% vs − 17%; p < 0.0001) and month 6 (− 61% vs − 23%; p < 0.0001). Overall and serious adverse events were similar between groups. In postmenopausal women who were suboptimally adherent to alendronate therapy, transitioning to denosumab was well tolerated and more effective than risedronate in increasing BMD and reducing bone turnover.
Background There is increasing evidence of the effect of maternal vitamin D intake during pregnancy on the risk of asthma and allergic outcomes in offspring. However, studies on the relationship ...between cord levels of 25-hydroxyvitamin D (25OHD) and asthma and allergic diseases are very few. Objective Our aim was to investigate the associations between cord serum 25(OH)D levels and asthma, wheezing, allergic rhinitis, and atopic dermatitis in the offspring from birth to 5 years. Methods Cord blood samples were collected at birth and analyzed for 25(OH)D levels in 239 newborns from the Etude des Déterminants pré et post natals du développement et de la santé de l′Enfant (EDEN) birth cohort. The children were followed up until age 5 years by using International Study of Asthma and Allergies in Childhood–based symptom questionnaires. Results The median cord serum level of 25(OH)D was 17.8 ng/mL (interquartile range, 15.1 ng/mL). By using multivariable-adjusted logistic regression models, a significant inverse association was observed between cord serum 25(OH)D levels and risk of transient early wheezing and early- and late-onset atopic dermatitis, as well as atopic dermatitis, by the ages of 1, 2, 3, and 5 years. We found no association between cord serum 25(OH)D levels and asthma and allergic rhinitis at age 5 years. Conclusions Cord serum 25(OH)D levels were inversely associated with the risk of transient early wheezing and atopic dermatitis by the age of 5 years, but no association was found with asthma and allergic rhinitis.
•Five to eight years’ post-vaccination, vaccine-related HPV genotypes were detected in only 1.7%.•Demonstration of ongoing decline of vaccine-related genotypes in young Australian women.•Participants ...were recruited via Facebook social networking website an effective and relatively inexpensive method.
The VACCINE Vaccine Against Cervical Cancer Impact and Effectiveness study evaluated the prevalence of quadrivalent vaccine-targeted human papillomavirus (HPV) genotypes (HPV 6, 11, 16, 18) amongst young women of vaccine-eligible age.
Between October 2011 – June 2015, women aged 18–25 years from Victoria, Australia, were recruited through targeted advertising on the social networking website Facebook. Participants completed an online questionnaire and provided a self-collected vaginal swab for HPV DNA detection and genotyping (Linear Array HPV genotyping assay). Self-reported HPV vaccination details were verified with the National HPV Vaccination Program Register (NHVPR).
Of 1223 who agreed to participate, 916 (74.9%) completed the survey and, for 1007 (82.3%) sexually-active participants, 744 (73.9%) returned the self-collected swab, of which 737 contained detectable DNA. 184/737 (25.0%) were positive for HPV. Vaccine-targeted HPV genotypes were detected in only 13 (1.7%) women: 11 HPV 16 (six vaccinated after sexual debut, five unvaccinated) and two HPV 6. Prevalence of any of HPV 31/33/45 collectively was 2.9%, varying significantly by vaccination status (fully 2.0%, unvaccinated 6.8%; p = 0.01). Vaccination rates among the sexually-active cohort were high, with 65.6%, 71.6% and 74.2% of participants having received three, at least two or at least one dose of vaccine, respectively. Of women self-reporting HPV vaccination, the NHVPR confirmed one or more doses were received in 90%. Strong associations were observed between vaccination status, age, language spoken at home and country of birth, as well as between HPV detection and the number of male sexual partners.
Surveillance five to eight years’ post-initiation of a national HPV vaccination program demonstrated a consistent and very low prevalence of vaccine-related HPV genotypes and some evidence of cross protection against related types amongst vaccine-eligible women from Victoria, Australia.
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