Comparative plasma catecholamine and hemodynamic responses to handgrip, cold pressor and supine bicycle exercise testing in normal subjects

Serial hemodynamic and plasma catecholamine responses were compared among 10 healthy men (27 ± 3 years) ( ± 1 standard deviation) during symptom-limited handgrip (33% maximal voluntary contraction for 4.4 ± 1.8 minutes), cold pressor testing (6 minutes) and symptom-limited supine bicycle exercise (22 ± 5 minutes). Plasma catecholamine concentrations were measured by radioenzymatic assays; ejection fraction and changes in cardiac volumes were assessed by equilibrium radionuclide angiography. During maximal supine exercise, plasma norepinephrine and epinephrine concentrations increased three to six times more than during either symptom-limited handgrip or cold pressor testing. Additionally, increases in heart rate, systolic blood pressure, rate-pressure product, stroke volume, ejection fraction and cardiac output were significantly greater during bicycle exercise than during the other two tests. A decrease in ejection fraction of 0.05 units or more was common in young normal subjects during the first 2 minutes of cold pressor testing (6 of 10 subjects) or at symptom-limited handgrip (3 of 10), but never occurred during maximal supine bicycle exercise.The magnitude of hemodynamic changes with maximal supine bicycle exercise was greater, more consistent and associated with much higher sympathetic nervous system activation, making this a potentially more useful diagnostic stress than either handgrip exercise or cold pressor testing

Impedance of an induction coil at the opening of a borehole in a conductor

The electromagnetic field of a cylindrical eddy current probe coil near the open end of a borehole in a conductor has been calculated analytically accounting for edge effects. Calculations of the coil impedance as a function of position and excitation frequency have been made allowing theoretical results to be compared with experimental measurements. Comparisons have been carried out for special cases in which a cylindrical coil has its axis either perpendicular or parallel to the axis of the hole. In the approach used, the field is expressed in terms of transverse electric and transverse magnetic potentials defined with respect to the axis of the hole. The domain of the problem is truncated in the axial direction in order to express the solution in the form of eigenfunction expansions. The truncation modifies the original unbounded domain problem, but the additional boundaries can be made as remote from the coil as desired so that they have a negligible effect on numerical estimates of the coil field. The truncated region approach has proved to be accurate and computationally efficient but more significantly, it allows new solutions to be found for problems that are otherwise analytically intractable. The results model eddy current inspections of boreholes including edge effects at the opening of the hole

On the exact electric and magnetic fields of an electric dipole

We derive from Jefimenko's equations a multipole expansion in order to obtain the exact expressions for the electric and magnetic fields of an electric dipole with an arbitrary time dependence. A few comments are also made about the usual expositions found in most common undergraduate and graduate textbooks as well as in the literature on this topic

Density matrix calculation of optical constants from optical to x-ray frequencies

We present a theory of linear optical constants based on a single-particle density matrix and implemented in an extension of the real-space multiple scattering code FEFF. This approach avoids the need to compute wave-functions explicitly, and yields efficient calculations for frequencies ranging from the IR to hard x-rays, and applicable to arbitrary aperiodic systems. Our approach is illustrated with calculations of optical properties and applications for several materials

The Effect of Body Size on Countermovement Jump Kinetics in Children aged 7 to 11 years

The purpose this study was to examine the effect of body size oncountermovement jump (CMJ)kinetics in children.Participants(n = 160) aged 7-11 years, divided equally by sex and into primary school year groups(years 3, 4, 5 and 6), each performedone CMJ on aforce platform. The variables bodyweight(BW), peak force (Fmax), in-jump minimum force (IMF), in-jump vertical force range (IFR) and basic rate of force development (BRFD)wereattained from the force-time history and then subsequently scaled to account for body size. A significant age, sex and interaction effect werefound for theabsolutevariables BW, IMF, Fmaxand IFR (P 0.05). No significant age or sex differences were observed for normalised or allometrically scaled values(P > 0.05). The results indicate thatgirls and boys can be grouped together but that body size must be accounted for to enable accurate conclusions to be drawn independent of growth.Bodysizesignificantlyeffects the representation of CMJ kinetic results and therefore, future studies should report both absolute and scaled values.Future research should developan age-appropriate criterion method for children in order to determine processed CMJ variables to further investigate neuromuscular performance of children

Effectiveness of pelvic floor muscle training with and without electromyographic biofeedback for urinary incontinence in women: multicentre randomised controlled trial

This is the final version. Available on open access from BMJ Publishing Group via the DOI in this recordObjective To assess the effectiveness of pelvic floor muscle training (PFMT) plus electromyographic biofeedback or PFMT alone for stress or mixed urinary incontinence in women. Design Parallel group randomised controlled trial. Setting 23 community and secondary care centres providing continence care in Scotland and England. Participants 600 women aged 18 and older, newly presenting with stress or mixed urinary incontinence between February 2014 and July 2016: 300 were randomised to PFMT plus electromyographic biofeedback and 300 to PFMT alone. Interventions Participants in both groups were offered six appointments with a continence therapist over 16 weeks. Participants in the biofeedback PFMT group received supervised PFMT and a home PFMT programme, incorporating electromyographic biofeedback during clinic appointments and at home. The PFMT group received supervised PFMT and a home PFMT programme. PFMT programmes were progressed over the appointments. Main outcome measures The primary outcome was self-reported severity of urinary incontinence (International Consultation on Incontinence Questionnaire-urinary incontinence short form (ICIQ-UI SF), range 0 to 21, higher scores indicating greater severity) at 24 months. Secondary outcomes were cure or improvement, other pelvic floor symptoms, condition specific quality of life, women’s perception of improvement, pelvic floor muscle function, uptake of other urinary incontinence treatment, PFMT self-efficacy, adherence, intervention costs, and quality adjusted life years. Results Mean ICIQ-UI SF scores at 24 months were 8.2 (SD 5.1, n=225) in the biofeedback PFMT group and 8.5 (SD 4.9, n=235) in the PFMT group (mean difference −0.09, 95% confidence interval −0.92 to 0.75, P=0.84). Biofeedback PFMT had similar costs (mean difference £121 ($154; €133), −£409 to £651, P=0.64) and quality adjusted life years (−0.04, −0.12 to 0.04, P=0.28) to PFMT. 48 participants reported an adverse event: for 23 this was related or possibly related to the interventions. Conclusions At 24 months no evidence was found of any important difference in severity of urinary incontinence between PFMT plus electromyographic biofeedback and PFMT alone groups. Routine use of electromyographic biofeedback with PFMT should not be recommended. Other ways of maximising the effects of PFMT should be investigated.National Institute for Health Research (NIHR

Single-cell paired-end genome sequencing reveals structural variation per cell cycle

The nature and pace of genome mutation is largely unknown. Because standard methods sequence DNA from populations of cells, the genetic composition of individual cells is lost, de novo mutations in cells are concealed within the bulk signal and per cell cycle mutation rates and mechanisms remain elusive. Although single-cell genome analyses could resolve these problems, such analyses are error-prone because of whole-genome amplification (WGA) artefacts and are limited in the types of DNA mutation that can be discerned. We developed methods for paired-end sequence analysis of single-cell WGA products that enable (i) detecting multiple classes of DNA mutation, (ii) distinguishing DNA copy number changes from allelic WGA-amplification artefacts by the discovery of matching aberrantly mapping read pairs among the surfeit of paired-end WGA and mapping artefacts and (iii) delineating the break points and architecture of structural variants. By applying the methods, we capture DNA copy number changes acquired over one cell cycle in breast cancer cells and in blastomeres derived from a human zygote after in vitro fertilization. Furthermore, we were able to discover and fine-map a heritable inter-chromosomal rearrangement t(1;16)(p36;p12) by sequencing a single blastomere. The methods will expedite applications in basic genome research and provide a stepping stone to novel approaches for clinical genetic diagnosis

Genomic evolution of breast cancer metastasis and relapse

A.G.L. and J.H.R.F. were supported by a Cancer Research UK Program Grant to Simon Tavaré (C14303/A17197).Patterns of genomic evolution between primary and metastatic breast cancer have not been studied in large numbers, despite patients with metastatic breast cancer having dismal survival. We sequenced whole genomes or a panel of 365 genes on 299 samples from 170 patients with locally relapsed or metastatic breast cancer. Several lines of analysis indicate that clones seeding metastasis or relapse disseminate late from primary tumors, but continue to acquire mutations, mostly accessing the same mutational processes active in the primary tumor. Most distant metastases acquired driver mutations not seen in the primary tumor, drawing from a wider repertoire of cancer genes than early drivers. These include a number of clinically actionable alterations and mutations inactivating SWI-SNF and JAK2-STAT3 pathways.Publisher PDFPeer reviewe