Experiment for Non-Interfering Coexistence of Non-Orthogonal SEFDM Signals and LTE

A non-orthogonal waveform, termed Nyquistspectrally efficient frequency division multiplexing (NyquistSEFDM), introduces benefits such as compressed bandwidth and low out-of-band power leakage, which meets two crucial requirements for future carrier aggregation (CA) or machinetype communication (MTC) applications. Both simulation and experimental results are presented in this work. A comparative simulation study of SEFDM signals is firstly presented to show the trade-offs between BER performance, bandwidth compression and suppressed out-of-band power leakage. Following modelling results, an enhanced multiuser diversity scenario was proposed to show future applications of SEFDM waveforms. Finally, an experimental testbed was designed to validate the coexistence of two signals. The impact of the newly proposed signals on existing 4 th generation (4G) signals is evaluated. Index Terms—Multicarrier, experiment, testbed, software de- fined radio, pulse shaping, spectral efficiency, carrier aggregation, OFDM, SEFDM, non-orthogonal

The First 15 Years of SEFDM: A Brief Survey

Spectrally efficient frequency division multiplexing (SEFDM) is a multi-carrier signal waveform, which achieves higher spectral efficiency, relative to conventional orthogonal frequency division multiplexing (OFDM), by violating the orthogonality of its sub-carriers. This survey provides the history of SEFDM development since its inception in 2003, covering fundamentals and concepts, wireless and optical communications applications, circuit design and experimental testbeds. We focus on work done at UCL and outline work done other universities and research laboratories worldwide. We outline techniques to improve the performance of SEFDM and its practical utility with focus on signal generation, detection and channel estimation

Insights into the pathogenesis of vein graft disease: lessons from intravascular ultrasound

The success of coronary artery bypass grafting (CABG) is limited by poor long-term graft patency. Saphenous vein is used in the vast majority of CABG operations, although 15% are occluded at one year with as many as 50% occluded at 10 years due to progressive graft atherosclerosis. Intravascular ultrasound (IVUS) has greatly increased our understanding of this process. IVUS studies have shown that early wall thickening and adaptive remodeling of vein grafts occurs within the first few weeks post implantation, with these changes stabilising in angiographically normal vein grafts after six months. Early changes predispose to later atherosclerosis with occlusive plaque detectable in vein grafts within the first year. Both expansive and constrictive remodelling is present in diseased vein grafts, where the latter contributes significantly to occlusive disease. These findings correlate closely with experimental and clinicopathological studies and help define the windows for prevention, intervention or plaque stabilisation strategies. IVUS is also the natural tool for evaluating the effectiveness of pharmacological and other treatments that may prevent or slow the progression of vein graft disease in clinical trials

Evaluation of 17-mm St. Jude Medical Regent prosthetic aortic heart valves by rest and dobutamine stress echocardiography

BACKGROUND: The prosthesis used for aortic valve replacement in patients with small aortic root can be too small in relation to body size, thus showing high transvalvular gradients at rest and/or under stress conditions. This study was carried out to evaluate rest and Dobutamine stress echocardiography (DSE) hemodynamic response of 17-mm St. Jude Medical Regent (SJMR-17 mm) in relatively aged patients at mean 24 months follow-up. METHODS AND RESULTS: The study population consisted of 19 patients (2 men, 17 women, mean age 69.2 ± 7.3 years). All patients underwent rest Doppler echocardiography before and after surgery and basal and DSE at follow up (infused at rate of 5 micrg/Kg/min and increased by 5 microg/Kg/min at 5 min intervals up to 40 microg/Kg/min). The following parameters were evaluated at rest and/or under DSE: heart rate (HR), ejection fraction (EF), cardiac output (CO), peak and mean velocity and pressure gradients (MxV, MnV, MxPG, MnPG), effective orifice area (EOA), indexed EOA (EOAi), left ventricular mass (LVM), indexed LVM (LVMi), Velocity Time Integral at left ventricular outflow tract (VTI LVOT) and transvalvular (Aortic VTI), Doppler velocity index (DVI). At rest MxPG and MnPG were 29.2 ± 7.1 and 16.6 ± 5.8mmHg, respectively; EOA and EOAi resulted 1.14 ± 0.3 cm(2) and 0.76 ± 0.2 cm(2)/m(2); DVI was normal (0.50 ± 0.1). At follow-up LVM and LVMi decreased significantly from pre-operative value of 258 ± 43g and 157.4 ± 27.7g/m(2) to 191 ± 23.8g and 114.5 ± 10.6g/m(2), respectively. DSE increased significantly HR, CO, EF, MxGP (up to 83.4 ± 2 1.9mmHg), MnPG (up to 43.2 ± 12.7mmHg). EOA, EOAi, DVI increased insignificantly (from baseline up to 1.2 ± 0.4 cm(2), 0.75 ± 0.3cm(2)/m(2) and 0.48 ± 0.1 respectively). Two patients developed significant intraventricular gradients. CONCLUSION: These data show that SJMR 17-mm prostheses can be safely implanted in aortic position in relatively aged patients, offering a satisfactory hemodynamic performance at rest and under DSE, with full utilization of its available orifice, suggesting that a possible mild prosthesis-patient mismatch is not an issue of clinical relevance when this small prosthesis is used. Rest and Dobutamine stress echocardiography is a useful and effective means for evaluating prosthesis hemodynamics and for monitoring the expected LVH regression

A Randomized Trial of Progesterone in Women with Bleeding in Early Pregnancy

BACKGROUND Bleeding in early pregnancy is strongly associated with pregnancy loss. Progesterone is essential for the maintenance of pregnancy. Several small trials have suggested that progesterone therapy may improve pregnancy outcomes in women who have bleeding in early pregnancy. METHODS We conducted a multicenter, randomized, double-blind, placebo-controlled trial to evaluate progesterone, as compared with placebo, in women with vaginal bleeding in early pregnancy. Women were randomly assigned to receive vaginal suppositories containing either 400 mg of progesterone or matching placebo twice daily, from the time at which they presented with bleeding through 16 weeks of gestation. The primary outcome was the birth of a live-born baby after at least 34 weeks of gestation. The primary analysis was performed in all participants for whom data on the primary outcome were available. A sensitivity analysis of the primary outcome that included all the participants was performed with the use of multiple imputation to account for missing data. RESULTS A total of 4153 women, recruited at 48 hospitals in the United Kingdom, were randomly assigned to receive progesterone (2079 women) or placebo (2074 women). The percentage of women with available data for the primary outcome was 97% (4038 of 4153 women). The incidence of live births after at least 34 weeks of gestation was 75% (1513 of 2025 women) in the progesterone group and 72% (1459 of 2013 women) in the placebo group (relative rate, 1.03; 95% confidence interval [CI], 1.00 to 1.07; P=0.08). The sensitivity analysis, in which missing primary outcome data were imputed, resulted in a similar finding (relative rate, 1.03; 95% CI, 1.00 to 1.07; P=0.08). The incidence of adverse events did not differ significantly between the groups. CONCLUSIONS Among women with bleeding in early pregnancy, progesterone therapy administered during the first trimester did not result in a significantly higher incidence of live births than placebo. (Funded by the United Kingdom National Institute for Health Research Health Technology Assessment program; PRISM Current Controlled Trials number, ISRCTN14163439. opens in new tab.

MRI screening for vestibular schwannoma in Wigan (UK)

Introduction: Acoustic neuromas are benign tumours which arise from Schwann cells of the vestibulocochlear nerve. Our guidelines recommend scanning if there is clinical evidence of sudden sensorineural hearing loss, unilateral tinnitus, fluctuating hearing loss, cerebellar or neurological signs or Meniere's disease. It also recommends scanning for patients with asymmetrical cochlear symptoms with normal pure tone audiogram or asymmetrical hearing loss judged as appropriate by air or bone conduction, of 40dB or more at two or 45 dB or more a three adjacent frequencies.Methods: To determine the diagnostic accuracy for this department we reviewed the records and MRI scans for all the patients with suspected acoustic neuroma over 1 year. All 446 scans in 2011 were reviewed retrospectively along with their case records and audiograms. The information was analysed against the local otolaryngology MRI guidelines.Results: 31 patients were found to have an acoustic neuroma. Of the patients who had normal findings on MRI, only 5% did not fit the guidelinesFollowing our review of the 449 patients, 75% had sudden sensorineural hearing loss, 54% had unilateral tinnitus, 0.5% had fluctuating hearing loss, 8% had imbalance, 8% had vertigo, 8% were dizzy, 3% had persistent headache, 2% had cranial nerve palsies, 2% had Menieres disease and 63% had an abnormal audiogram.Conclusion: It was concluded that our department had a 95% adherence rate to our current local guidelines. Compared to the literature we have a comparable rate of incidence of acoustic neuromas. We would therefore encourage that all departments have similar local guidelines to ensure that patients are managed appropriatelyUnterstützt durch: Wigan, Wrightington and Leigh Health Foundation TrustDer Erstautor gibt keinen Interessenkonflikt an