332 research outputs found
SO(5,5) duality in M-theory and generalized geometry
We attempt to reformulate eleven dimensional supergravity in terms of an
object that unifies the three-form and the metric and makes the M-theory
duality group manifest. This short note deals with the case of where the
U-duality group SO(5,5) acts in five spatial dimensions.Comment: 7 pages, LaTex, v2: typos corrected and reference adde
Exercise interventions for people undergoing multimodal cancer treatment that includes surgery
This is the protocol for a review and there is no abstract. The objectives are as follows: To determine the effect of exercise interventions for people undergoing multimodal treatment including surgery on physical fitness, safety and feasibility, health-related quality of life and other important health outcomes
Physical activity levels in locally advanced rectal cancer patients following neoadjuvant chemoradiotherapy and an exercise training programme before surgery: a pilot study
Background: The aim of this pilot study was to measure changes in physical activity level (PAL) variables, as well as sleep duration and efficiency in people with locally advanced rectal cancer (1) before and after neoadjuvant chemoradiotherapy (CRT) and (2) after participating in a pre-operative 6-week in-hospital exercise training programme, following neoadjuvant CRT prior to major surgery, compared to a usual care control group.Methods: We prospectively studied 39 consecutive participants (27 males). All participants completed standardised neoadjuvant CRT: 23 undertook a 6-week in-hospital exercise training programme following neoadjuvant CRT. These were compared to 16 contemporaneous non-randomised participants (usual care control group). All participants underwent a continuous 72-h period of PA monitoring by SenseWear biaxial accelerometer at baseline, immediately following neoadjuvant CRT (week 0), and at week 6 (following the exercise training programme).Results: Of 39 recruited participants, 23 out of 23 (exercise) and 10 out of 16 (usual care control) completed the study. In all participants (n = 33), there was a significant reduction from baseline (pre-CRT) to week 0 (post-CRT) in daily step count: median (IQR) 4966 (4435) vs. 3044 (3265); p < 0.0001, active energy expenditure (EE) (kcal): 264 (471) vs. 154 (164); p = 0.003, and metabolic equivalent (MET) (1.3 (0.6) vs. 1.2 (0.3); p = 0.010). There was a significant improvement in sleep efficiency (%) between week 0 and week 6 in the exercise group compared to the usual care control group (80 (13) vs. 78 (15) compared to (69 ((24) vs. 76 (20); p = 0.022), as well as in sleep duration and lying down time (p < 0.05) while those in active EE (kcal) (152 (154) vs. 434 (658) compared to (244 (198) vs. 392 (701) or in MET (1.3 (0.4) vs. 1.5 (0.5) compared to (1.1 (0.2) vs. 1.5 (0.5) were also of importance but did not reach statistical significance (p > 0.05). An apparent improvement in daily step count and overall PAL in the exercise group was not statistically significant.Conclusions: PAL variables, daily step count, EE and MET significantly reduced following neoadjuvant CRT in all participants. A 6-week pre-operative in-hospital exercise training programme improved sleep efficiency, sleep duration and lying down time when compared to participants receiving usual care
Pulmonary Artery Catheter (PAC) Accuracy and Efficacy Compared with Flow Probe and Transcutaneous Doppler (USCOM): An Ovine Cardiac Output Validation
Background. The pulmonary artery catheter (PAC) is an accepted clinical method of measuring cardiac output (CO) despite no prior validation. The ultrasonic cardiac output monitor (USCOM) is a noninvasive alternative to PAC using Doppler ultrasound (CW). We compared PAC and USCOM CO measurements against a gold standard, the aortic flow probe (FP), in sheep at varying outputs. Methods. Ten conscious sheep, with implanted FPs, had measurements of CO by FP, USCOM, and PAC, at rest and during intervention with inotropes and vasopressors. Results. CO measurements by FP, PAC, and USCOM were 4.0 ± 1.2 L/min, 4.8 ± 1.5 L/min, and 4.0 ± 1.4 L/min, respectively, (n = 280, range 1.9 L/min to 11.7 L/min). Percentage bias and precision between FP and PAC, and FP and USCOM was −17 and 47%, and 1 and 36%, respectively. PAC under-measured Dobutamine-induced CO changes by 20% (relative 66%) compared with FP, while USCOM measures varied from FP by 3% (relative 10%). PAC reliably detected −30% but not +40% CO changes, as measured by receiver operating characteristic area under the curve (AUC), while USCOM reliably detected ±5% changes in CO (AUC > 0.70). Conclusions. PAC demonstrated poor accuracy and sensitivity as a measure of CO. USCOM provided equivalent measurements to FP across a sixfold range of outputs, reliably detecting ±5% changes
The local symmetries of M-theory and their formulation in generalised geometry
In the doubled field theory approach to string theory, the T-duality group is
promoted to a manifest symmetry at the expense of replacing ordinary Riemannian
geometry with generalised geometry on a doubled space. The local symmetries are
then given by a generalised Lie derivative and its associated algebra. This
paper constructs an analogous structure for M-theory. A crucial by-product of
this is the derivation of the physical section condition for M-theory
formulated in an extended space.Comment: 20 pages, v2: Author Name corrected, v3: typos correcte
Duality Invariant Actions and Generalised Geometry
We construct the non-linear realisation of the semi-direct product of E(11)
and its first fundamental representation at lowest order and appropriate to
spacetime dimensions four to seven. This leads to a non-linear realisation of
the duality groups and introduces fields that depend on a generalised space
which possess a generalised vielbein. We focus on the part of the generalised
space on which the duality groups alone act and construct an invariant action.Comment: 59 pages (typos fixed and added comments
Realistic Earth escape strategies for solar sailing
With growing interest in solar sailing comes the requirement to provide a basis for future detailed planetary escape mission analysis by drawing together prior work, clarifying and explaining previously anomalies. Previously unexplained seasonal variations in sail escape times from Earth orbit are explained analytically and corroborated within a numerical trajectory model. Blended-sail control algorithms, explicitly independent of time, which providenear-optimal escape trajectories and maintain a safe minimum altitude and which are suitable as a potential autonomous onboard controller, are then presented. These algorithms are investigated from a range of initial conditions and are shown to maintain the optimality previously demonstrated by the use of a single-energy gain control law but without the risk of planetary collision. Finally, it is shown that the minimum sail characteristic acceleration required for escape from a polar orbit without traversing the Earth shadow cone increases exponentially as initial altitude is decreased
Generalized Geometry and M theory
We reformulate the Hamiltonian form of bosonic eleven dimensional
supergravity in terms of an object that unifies the three-form and the metric.
For the case of four spatial dimensions, the duality group is manifest and the
metric and C-field are on an equal footing even though no dimensional reduction
is required for our results to hold. One may also describe our results using
the generalized geometry that emerges from membrane duality. The relationship
between the twisted Courant algebra and the gauge symmetries of eleven
dimensional supergravity are described in detail.Comment: 29 pages of Latex, v2 References added, typos fixed, v3 corrected
kinetic term and references adde
Silencing the epidermal growth factor receptor gene with RNAi may be developed as a potential therapy for non small cell lung cancer
Lung cancer has emerged as a leading cause of cancer death in the world. Non-small cell lung cancer (NSCLC) accounts for 75–80% of all lung cancers. Current therapies are ineffective, thus new approaches are needed to improve the therapeutic ratio. Double stranded RNA (dsRNA) -mediated RNA interference (RNAi) has shown promise in gene silencing, the potential of which in developing new methods for the therapy of NSCLC needs to be tested. We report here RNAi induced effective silencing of the epidermal growth factor receptor (EGFR) gene, which is over expressed in NSCLC. NSCLC cell lines A549 and SPC-A1 were transfected with sequence- specific dsRNA as well as various controls. Immune fluorescent labeling and flow cytometry were used to monitor the reduction in the production of EGFR protein. Quantitative reverse-transcriptase PCR was used to detect the level of EGFR mRNA. Cell count, colony assay, scratch assay, MTT assay in vitro and tumor growth assay in athymic nude mice in vivo were used to assess the functional effects of EGFR silencing on tumor cell growth and proliferation. Our data showed transfection of NSCLC cells with dsRNA resulted in sequence specific silencing of EGFR with 71.31% and 71.78 % decreases in EGFR protein production and 37.04% and 54.92% in mRNA transcription in A549 and SPC-A1 cells respectively. The decrease in EGFR protein production caused significant growth inhibition, i.e.: reducing the total cell numbers by 85.0% and 78.3 %, and colony forming numbers by 63.3% and 66.8%. These effects greatly retarded the migration of NSCLC cells by more than 80% both at 24 h and at 48 h, and enhanced chemo-sensitivity to cisplatin by four-fold in A549 cells and seven-fold in SPC-A1. Furthermore, dsRNA specific for EGFR inhibited tumor growth in vivo both in size by 75.06 % and in weight by 73.08 %. Our data demonstrate a new therapeutic effect of sequence specific suppression of EGFR gene expression by RNAi, enabling inhibition of tumor proliferation and growth. However, in vivo use of dsRNA for gene transfer to tumor cells would be limited because dsRNA would be quickly degraded once delivered in vivo. We thus tested a new bovine lentiviral vector and showed lentivector-mediated RNAi effects were efficient and specific. Combining RNAi with this gene delivery system may enable us to develop RNAi for silencing EGFR into an effective therapy for NSCLC
- …