124 research outputs found
Comparison of copper and tungsten carbide calibration spheres
Author Posting. Š Acoustical Society of America, 1984. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 75 (1984): 612-616, doi:10.1121/1.390489.The properties of calibration spheres made from electricalâgrade copper, denoted Cu, and tungsten carbide with 6% cobalt binder, denoted WC, are examined theoretically. Effects of variations in material, medium, and equipment parameters are determined for spheres intended to calibrate 38âkHz echo sounders when a target strength of order â41.5 dB is required. The derived 30.4âmmâdiam Cu sphere and selected 38.1âmmâdiam WC ball bearing show different dependences on the varied parameters. Changes in the material and equipment parameters within wide ranges will not upset a precision calibration with expected Âą0.1âdB accuracy. Adjustment of the calibration value of âbackscattering cross section with changing temperature is generally necessary for elastic spheres. This is the case for the present WC sphere, but not for the Cu sphere by virtue of its optimization with respect to temperature. Greater hardness is found to be insufficient for choosing between the two; the particular application must be considered. Pragmatic criteria for sphere selection are discussed
Molecular cloning of cDNA encoding human and rabbit forms of the Ca2+ release channel (ryanodine receptor) of skeletal muscle sarcoplasmic reticulum.
We have cloned cDNAs encoding the rabbit and human forms of the Ca2+ release channel of sarcoplasmic reticulum. The human cDNA encodes a protein of 5032 amino acids, with a molecular weight of 563,584, which is made without an NH2-terminal signal sequence. Amino acid substitutions between rabbit and human sequences were noted in 163 positions and deletions or insertions in eight regions accounted for additional sequence differences between the two proteins. Analysis of the sequence indicates that 10 potential transmembrane sequences in the COOH-terminal fifth of the molecule and two additional, potential transmembrane sequences nearer to the center of the molecule could contribute to the formation of the Ca2+ conducting pore. The remainder of the molecule is hydrophilic and presumably constitutes the cytoplasmic domain of the protein. A 114-120 amino acid motif is repeated four times in the protein, in residues 841-954, 955-1068, 2725-2844, and 2845-2958 and a 16 amino acid part of the motif is repeated twice more in residues 1344-1359 and 1371-1386. Although the channel is modulated by Ca2+, ATP, and calmodulin, no clear high affinity Ca2(+)-binding domain of the EF hand type and no clear high affinity ATP-binding domain were detected in the primary sequence. An acidic sequence in residues 1872-1923 contains 79% glutamate or aspartate residues and this sequence is a potential low affinity Ca2(+)-binding site. Several potential calmodulin-binding sites were observed in the sequence, in the region 2800 to 3050
Observational and Dynamical Characterization of Main-Belt Comet P/2010 R2 (La Sagra)
We present observations of comet-like main-belt object P/2010 R2 (La Sagra)
obtained by Pan-STARRS 1 and the Faulkes Telescope-North on Haleakala in
Hawaii, the University of Hawaii 2.2 m, Gemini-North, and Keck I telescopes on
Mauna Kea, the Danish 1.54 m telescope at La Silla, and the Isaac Newton
Telescope on La Palma. An antisolar dust tail is observed from August 2010
through February 2011, while a dust trail aligned with the object's orbit plane
is also observed from December 2010 through August 2011. Assuming typical phase
darkening behavior, P/La Sagra is seen to increase in brightness by >1 mag
between August 2010 and December 2010, suggesting that dust production is
ongoing over this period. These results strongly suggest that the observed
activity is cometary in nature (i.e., driven by the sublimation of volatile
material), and that P/La Sagra is therefore the most recent main-belt comet to
be discovered. We find an approximate absolute magnitude for the nucleus of
H_R=17.9+/-0.2 mag, corresponding to a nucleus radius of ~0.7 km, assuming an
albedo of p=0.05. Using optical spectroscopy, we find no evidence of
sublimation products (i.e., gas emission), finding an upper limit CN production
rate of Q_CN<6x10^23 mol/s, from which we infer an H2O production rate of
Q_H2O<10^26 mol/s. Numerical simulations indicate that P/La Sagra is
dynamically stable for >100 Myr, suggesting that it is likely native to its
current location and that its composition is likely representative of other
objects in the same region of the main belt, though the relatively close
proximity of the 13:6 mean-motion resonance with Jupiter and the (3,-2,-1)
three-body mean-motion resonance with Jupiter and Saturn mean that dynamical
instability on larger timescales cannot be ruled out.Comment: 23 pages, 13 figures, accepted for publication in A
Solitary fibrous tumour of the genitourinary tract: a clinicopathological study of 11 cases and their association with the NAB2-STAT6 fusion gene
Aims To characterise clinicopathological features and clinical outcomes of the genitourinary tract solitary fibrous tumours, incorporating NAB2-STAT6 gene fusion status.
Methods The presence of the molecular hallmark NAB2-STAT6 gene fusion and for the defining fusion partner product STAT6 was assessed in 11 cases of the genitourinary tract solitary fibrous tumours. NAB2-STAT6 gene fusion analysis was performed using a break-apart fluorescence in situ hybridisation (FISH) probe using a probe cocktail with Bacterial artificial chromosome (BAC) clones for STAT6 and NAB2.
Results Eleven solitary fibrous tumours were diagnosed in eight male patients and three female patients with a mean age of 46â
years (range: 11â64â
years). Four of the tumours had malignant histological features, and three were considered moderate risk for metastasis. With a mean follow-up time of 61â
months, 1 recurred locally and 2 presented at distant metastatic sites. Using a break-apart FISH probe cocktail, we found the NAB2-STAT6 gene fusion and nuclear STAT6 expression in 58% and 91% of cases, respectively. However, the NAB2-STAT6 fusion status was not correlated with STAT6 expression or useful in discriminating between malignant histological features or subsequent clinical outcomes in the genitourinary solitary fibrous tumours.
Conclusions A subset of solitary fibrous tumours of the genitourinary tract behaved aggressively. Using a break-apart FISH probe cocktail, we found the NAB2-STAT6 gene fusion in 64% of cases. However, the NAB2-STAT6 fusion status was not correlated with STAT6 expression or useful in discriminating between low-risk or high-risk tumours and subsequent clinical outcomes
Depth-dependent target strengths of gadoids by the boundary-element method
Author Posting. Š Acoustical Society of America, 2003. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 114 (2003): 3136-3146, doi:10.1121/1.1619982.The depth dependence of fish target strength has mostly eluded experimental investigation because of the need to distinguish it from depth-dependent behavioral effects, which may change the orientation distribution. The boundary-element method (BEM) offers an avenue of approach. Based on detailed morphometric data on 15 gadoid swimbladders, the BEM has been exercised to determine how the orientation dependence of target strength changes with pressure under the assumption that the fish swimbladder remains constant in shape and volume. The backscattering cross section has been computed at a nominal frequency of 38 kHz as a function of orientation for each of three pressures: 1, 11, and 51 atm. Increased variability in target strength and more abundant and stronger resonances are both observed with increasing depth. The respective backscattering cross sections have been averaged with respect to each of four normal distributions of tilt angle, and the corresponding target strengths have been regressed on the logarithm of fish length. The tilt-angle-averaged backscattering cross sections at the highest pressure have also been averaged with respect to frequency over a 2-kHz band for representative conditions of insonification. For all averaging methods, the mean target strength changes only slightly with depth.This work began with sponsorship by the European Commission through its RTD-program, Contract No. MAS3-CT95-0031 (BASS), and was completed with support by the Office of Naval Research, Contract No. N000140310368
Increasing follow-up questionnaire response rates in a randomized controlled trial of telehealth for depression: three embedded controlled studies
Background: Attrition is problematic in trials, and may be exacerbated in longer studies, telehealth trials and participants with depression â three features of The Healthlines Study. Advance notification, including a photograph and using action-oriented email subject lines might increase response rates, but require further investigation. We examined the effectiveness of these interventions in three embedded Healthlines studies.
Methods: Based in different trial sites, participants with depression were alternately allocated to be pre-called or not ahead of the 8-month follow-up questionnaire (Study 1), randomized to receive a research team photograph or not with their 12-month questionnaire (Study 2), and randomized to receive an action-oriented (âACTION REQUIREDâ) or standard (âQuestionnaire reminderâ) 12-month email reminder (Study 3). Participants could complete online or postal questionnaires, and received up to five questionnaire reminders. The primary outcome was completion of the Patient Health Questionnaire (PHQ-9). Secondary outcome measures were the number of reminders and time to questionnaire completion.
Results: Of a total of 609 Healthlines depression participants, 190, 251 and 231 participants were included in Studies 1â3 (intervention: 95, 126 and 115), respectively. Outcome completion was âĽ90 % across studies, with no differences between trial arms (Study 1: OR 0.38, 95 % CI 0.07â2.10; Study 2: OR 0.84, 95 % CI 0.26â2.66; Study 3: OR 0.53 95 % CI 0.19â1.49). Pre-called participants were less likely to require a reminder (48.4 % vs 62.1 %, OR 0.41, 95 % CI 0.21â0.78), required fewer reminders (adjusted difference in means â0.67, 95 % CI â1.13 to â0.20), and completed follow-up quicker (median 8 vs 15 days, HR 1.35, 95 % CI 1.00â1.82) than control subjects. There were no significant between-group differences in Studies 2 or 3.
Conclusions: Eventual response rates in this trial were high, with no further improvement from these interventions. While the photograph and email interventions were ineffective, pre-calling participants reduced time to completion. This strategy might be helpful when the timing of study completion is important. Researchers perceived a substantial benefit from the reduction in reminders with pre-calling, despite no overall decrease in net effort after accounting for pre-notification
The evolution and storage of primitive melts in the Eastern Volcanic Zone of Iceland: the 10Â ka GrĂmsvĂśtn tephra series (i.e. the Saksunarvatn ash)
Major, trace and volatile elements were measured in a suite of primitive macrocrysts and melt inclusions from the thickest layer of the 10 ka GrĂmsvĂśtn tephra series (i.e. Saksunarvatn ash) at Lake HvĂtĂĄrvatn in central Iceland. In the absence of primitive tholeiitic eruptions (MgO > 7 wt.%) within the Eastern Volcanic Zone (EVZ) of Iceland, these crystal and inclusion compositions provide an important insight into magmatic processes in this volcanically productive region. Matrix glass compositions show strong similarities with glass compositions from the AD 1783â84 Laki eruption, confirming the affinity of the tephra series with the GrĂmsvĂśtn volcanic system. Macrocrysts can be divided into a primitive assemblage of zoned macrocryst cores (An_78âAn_92, Mg#_cpx = 82â87, Fo_79.5âFo_87) and an evolved assemblage consisting of unzoned macrocrysts and the rims of zoned macrocrysts (An_60âAn_68, Mg#_cpx = 71â78, Fo_70âFo_76). Although the evolved assemblage is close to being in equilibrium with the matrix glass, trace element disequilibrium between primitive and evolved assemblages indicates that they were derived from different distributions of mantle melt compositions. Juxtaposition of disequilibrium assemblages probably occurred during disaggregation of incompatible trace element-depleted mushes (mean La/Yb_melt = 2.1) into aphyric and incompatible trace element-enriched liquids (La/Yb_melt = 3.6) shortly before the growth of the evolved macrocryst assemblage. Post-entrapment modification of plagioclase-hosted melt inclusions has been minimal and high-Mg# inclusions record differentiation and mixing of compositionally variable mantle melts that are amongst the most primitive liquids known from the EVZ. Coupled high field strength element (HFSE) depletion and incompatible trace element enrichment in a subset of primitive plagioclase-hosted melt inclusions can be accounted for by inclusion formation following plagioclase dissolution driven by interaction with plagioclase-undersaturated melts. Thermobarometric calculations indicate that final crystal-melt equilibration within the evolved assemblage occurred at ~1140°C and 0.0â1.5 kbar. Considering the large volume of the erupted tephra and textural evidence for rapid crystallisation of the evolved assemblage, 0.0â1.5 kbar is considered unlikely to represent a pressure of long-term magma accumulation and storage. Multiple thermometers indicate that the primitive assemblage crystallised at high temperatures of 1240â1300°C. Different barometers, however, return markedly different crystallisation depth estimates. Raw clinopyroxene-melt pressures of 5.5â7.5 kbar conflict with apparent melt inclusion entrapment pressures of 1.4 kbar. After applying a correction derived from published experimental data, clinopyroxene-melt equilibria return mid-crustal pressures of 4Âą1.5 kbar, which are consistent with pressures estimated from the major element content of primitive melt inclusions. Long-term storage of primitive magmas in the mid-crust implies that low CO_2 concentrations measured in primitive plagioclase-hosted inclusions (262â800 ppm) result from post-entrapment CO_2 loss during transport through the shallow crust. In order to reconstruct basaltic plumbing system geometries from petrological data with greater confidence, mineral-melt equilibrium models require refinement at pressures of magma storage in Iceland. Further basalt phase equilibria experiments are thus needed within the crucial 1â7 kbar range.D.A.N. was supported by a Natural Environment Research Council studentship (NE/1528277/1) at the start of this project. SIMS analyses were supported by Natural Environment Research Council Ion Microprobe Facility award (IMF508/1013).This is the final version of the article. It first appeared from Springer via http://dx.doi.org/10.1007/s00410-015-1170-
Synthetic sling or artificial urinary sphincter for men with urodynamic stress incontinence after prostate surgery: The MASTER non-inferiority RCT
BACKGROUND: Stress urinary incontinence is common in men after prostate surgery and can be difficult to improve. Implantation of an artificial urinary sphincter is the most common surgical procedure for persistent stress urinary incontinence, but it requires specialist surgical skills, and revisions may be necessary. In addition, the sphincter is relatively expensive and its operation requires adequate patient dexterity. New surgical approaches include the male synthetic sling, which is emerging as a possible alternative. However, robust comparable data, derived from randomised controlled trials, on the relative safety and efficacy of the male synthetic sling and the artificial urinary sphincter are lacking. OBJECTIVE: We aimed to compare the clinical effectiveness and cost-effectiveness of the male synthetic sling with those of the artificial urinary sphincter surgery in men with persistent stress urinary incontinence after prostate surgery. DESIGN: This was a multicentre, non-inferiority randomised controlled trial, with a parallel non-randomised cohort and embedded qualitative component. Randomised controlled trial allocation was carried out by remote web-based randomisation (1â:â1), minimised on previous prostate surgery (radical prostatectomy or transurethral resection of the prostate), radiotherapy (or not, in relation to prostate surgery) and centre. Surgeons and participants were not blind to the treatment received. Non-randomised cohort allocation was participant and/or surgeon preference. SETTING: The trial was set in 28 UK urological centres in the NHS. PARTICIPANTS: Participants were men with urodynamic stress incontinence after prostate surgery for whom surgery was deemed appropriate. Exclusion criteria included previous sling or artificial urinary sphincter surgery, unresolved bladder neck contracture or urethral stricture after prostate surgery, and an inability to give informed consent or complete trial documentation. INTERVENTIONS: We compared male synthetic sling with artificial urinary sphincter. MAIN OUTCOME MEASURES: The clinical primary outcome measure was men's reports of continence (assessed from questions 3 and 4 of the International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form) at 12 months post randomisation (with a non-inferiority margin of 15%). The primary economic outcome was cost-effectiveness (assessed as the incremental cost per quality-adjusted life-year at 24 months post randomisation). RESULTS: In total, 380 men were included in the randomised controlled trial (nâ=â190 in each group), and 99 out of 100 men were included in the non-randomised cohort. In terms of continence, the male sling was non-inferior to the artificial urinary sphincter (intention-to-treat estimated absolute risk difference -0.034, 95% confidence interval -0.117 to 0.048; non-inferiority pâ=â0.003), indicating a lower success rate in those randomised to receive a sling, but with a confidence interval excluding the non-inferiority margin of -15%. In both groups, treatment resulted in a reduction in incontinence symptoms (as measured by the International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form). Between baseline and 12 months' follow-up, the International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form score fell from 16.1 to 8.7 in the male sling group and from 16.4 to 7.5 in the artificial urinary sphincter group (mean difference for the time point at 12 months 1.30, 95% confidence interval 0.11 to 2.49; pâ=â0.032). The number of serious adverse events was small (male sling group, nâ=â8; artificial urinary sphincter group, nâ=â15; one man in the artificial urinary sphincter group experienced three serious adverse events). Quality-of-life scores improved and satisfaction was high in both groups. Secondary outcomes that showed statistically significant differences favoured the artificial urinary sphincter over the male sling. Outcomes of the non-randomised cohort were similar. The male sling cost less than the artificial sphincter but was associated with a smaller quality-adjusted life-year gain. The incremental cost-effectiveness ratio for male slings compared with an artificial urinary sphincter suggests that there is a cost saving of ÂŁ425,870 for each quality-adjusted life-year lost. The probability that slings would be cost-effective at a ÂŁ30,000 willingness-to-pay threshold for a quality-adjusted life-year was 99%. LIMITATIONS: Follow-up beyond 24 months is not available. More specific surgical/device-related pain outcomes were not included. CONCLUSIONS: Continence rates improved from baseline, with the male sling non-inferior to the artificial urinary sphincter. Symptoms and quality of life significantly improved in both groups. Men were generally satisfied with both procedures. Overall, secondary and post hoc analyses favoured the artificial urinary sphincter over the male sling. FUTURE WORK: Participant reports of any further surgery, satisfaction and quality of life at 5-year follow-up will inform longer-term outcomes. Administration of an additional pain questionnaire would provide further information on pain levels after both surgeries. TRIAL REGISTRATION: This trial is registered as ISRCTN49212975. FUNDING: This project was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 26, No. 36. See the NIHR Journals Library website for further project information
Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial
Background
Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy
A Phase II, Randomized Study on an Investigational DTPw-HBV/Hib-MenAC Conjugate Vaccine Administered to Infants in Northern Ghana
BACKGROUND: Combining meningococcal vaccination with routine immunization in infancy may reduce the burden of meningococcal meningitis, especially in the meningitis belt of Africa. We have evaluated the immunogenicity, persistence of immune response, immune memory and safety of an investigational DTPw-HBV/Hib-MenAC conjugate vaccine given to infants in Northern Ghana. METHODS AND FINDINGS: In this phase II, double blind, randomized, controlled study, 280 infants were primed with DTPw-HBV/Hib-MenAC or DTPw-HBV/Hib vaccines at 6, 10 and 14 weeks of age. At 12 months of age, children in each group received a challenge dose of serogroup A+C polysaccharides. Antibody responses were assessed pre, and one month-post dose 3 of the priming schedule and pre and 1 month after administration of the challenge dose. One month post-dose 3, 87.8% and 88.2% of subjects in the study group had bactericidal meningococcal serogroup A (SBA-MenA) and meningococcal serogroup C (SBA-MenC) antibody titres > or = 1:8 respectively. Seroprotection/seropositivity rates to the 5 antigens administered in the routine EPI schedule were non-inferior in children in the study group compared to those in the control group. The percentages of subjects in the study group with persisting SBA-MenA titres > or = 1:8 or SBA-MenC titres > or = 1:8 at the age of 12 months prior to challenge were significantly higher than in control group (47.7% vs 25.7% and 56.4% vs 5.1% respectively). The administration of 10 microg of serogroup A polysaccharide increased the SBA-MenA GMT by 14.0-fold in the DTPW-HBV/HibMenAC-group compared to a 3.8 fold increase in the control-group. Corresponding fold-increases in SBA-MenC titres following challenge with 10 microg of group C polysaccharide were 18.8 and 1.9 respectively. Reactogenicity following primary vaccination or the administration of the challenge dose was similar in both groups, except for swelling (Grade 3) after primary vaccination which was more frequent in children in the vaccine than in the control group (23.7%; 95%CI [19.6-28.1] of doses vs 14.1%; 95% CI [10.9-17.8] of doses). Fifty-nine SAEs (including 8 deaths), none of them related to vaccination, were reported during the entire study. CONCLUSIONS: Three dose primary vaccination with DTPw-HBV/Hib-MenAC was non-inferior to DTPw-HBV/Hib for the 5 common antigens used in the routine EPI schedule and induced bactericidal antibodies against Neisseria meningitidis of serogroups A and C in the majority of infants. Serogroup A and C bactericidal antibody levels had fallen below titres associated with protection in nearly half of the infants by the age of 12 months confirming that a booster dose is required at about that age. An enhanced memory response was shown after polysaccharide challenge. This vaccine could provide protection against 7 important childhood diseases (including meningococcal A and C) and be of particular value in countries of the African meningitis belt. TRIAL REGISTRATION: Controlled-Trials.com ISRCTN35754083
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