An alternative to a randomised control design for assessing the efficacy and effectiveness of bracing in adolescent idiopathic scoliosis

Randomised controlled trials (RCTs) that assessed the efficacy of bracing for adolescent idiopathic scoliosis have suffered from small sample sizes, low compliance and lack of willingness to participate. The aim of this study was to assess the feasibility of a comprehensive cohort study for evaluating both the efficacy and the effectiveness of bracing in patients with adolescent idiopathic scoliosis. Patients with curves at greater risk of progression were invited to join a randomised controlled trial. Those who declined were given the option to remain in the study and to choose whether they wished to be braced or observed. Of 87 eligible patients (5 boys and 63 girls) identified over one year, 68 (78%) with mean age of 12.5 years (10 to 15) consented to participate, with a mean follow-up of 168 weeks (0 to 290). Of these, 19 (28%) accepted randomisation. Of those who declined randomisation, 18 (37%) chose a brace. Patients who were more satisfied with their image were more likely to choose bracing (Odds Ratio 4.1; 95% confidence interval 1.1 to 15.0; p = 0.035). This comprehensive cohort study design facilitates the assessment of both efficacy and effectiveness of bracing in patients with adolescent idiopathic scoliosis, which is not feasible in a conventional randomised controlled trial.postprin

Ultrafast control of donor-bound electron spins with single detuned optical pulses

The ability to control spins in semiconductors is important in a variety of fields including spintronics and quantum information processing. Due to the potentially fast dephasing times of spins in the solid state [1-3], spin control operating on the picosecond or faster timescale may be necessary. Such speeds, which are not possible to attain with standard electron spin resonance (ESR) techniques based on microwave sources, can be attained with broadband optical pulses. One promising ultrafast technique utilizes single broadband pulses detuned from resonance in a three-level Lambda system [4]. This attractive technique is robust against optical pulse imperfections and does not require a fixed optical reference phase. Here we demonstrate the principle of coherent manipulation of spins theoretically and experimentally. Using this technique, donor-bound electron spin rotations with single-pulse areas exceeding pi/4 and two-pulses areas exceeding pi/2 are demonstrated. We believe the maximum pulse areas attained do not reflect a fundamental limit of the technique and larger pulse areas could be achieved in other material systems. This technique has applications from basic solid-state ESR spectroscopy to arbitrary single-qubit rotations [4, 5] and bang-bang control[6] for quantum computation.Comment: 15 pages, 4 figures, submitted 12/2008. Since the submission of this work we have become aware of related work: J. Berezovsky, M. H. Mikkelsen, N. G. Stoltz, L. A. Coldren, and D. D. Awschalom, Science 320: 349-352 (2008

Nuclear spin pair coherence in diamond for atomic scale magnetometry

The nitrogen-vacancy (NV) centre, as a promising candidate solid state system of quantum information processing, its electron spin coherence is influenced by the magnetic field fluctuations due to the local environment. In pure diamonds, the environment consists of hundreds of C-13 nuclear spins randomly spreading in several nanometers range forming a spin bath. Controlling and prolonging the electron spin coherence under the influence of spin bath are challenging tasks for the quantum information processing. On the other hand, for a given bath distribution, many of its characters are encoded in the electron spin coherence. So it is natural to ask the question: is it possible to 'decode' the electron spin coherence, and extract the information about the bath structures? Here we show that, among hundreds of C-13 bath spins, there exist strong coupling clusters, which give rise to the millisecond oscillations of the electron spin coherence. By analyzing these oscillation features, the key properties of the coherent nuclear spin clusters, such as positions, orientations, and coupling strengths, could be uniquely identified. This addressability of the few-nuclear-spin cluster extends the feasibility of using the nuclear spins in diamond as qubits in quantum computing. Furthermore, it provides a novel prototype of single-electron spin based, high-resolution and ultra-sensitive detector for the chemical and biological applications.Comment: 15 pages, 4 figures, Nature Nanotechnology (2011

Is there a better alternative to a randomized control design for assessing the efficacy and effectiveness of bracing in AiS?

Session VII – Adolescent / Outcomes / Congenital Scoliosis - Podium Presentation Abstracts: paper no. 87SUMMARY: With the support of the Scoliosis Research Society, we examined the feasibility of conducting a single-blind comprehensive cohort study that assesses both efficacy and effectiveness of bracing in AIS. The study incorporates a RCT and an option allowing patients to choose their desirable treatment. Besides, it also has a treatment exit plan for those with significant progression. Our study showed that it outperforms a conventional RCT in terms of recruitment ability. INTRODUCTION: Current randomized controlled trials (RCTs) for assessing the efficacy of bracing in patients with adolescent idiopathic scoliosis (AIS) suffer from poor recruitment. Besides, patients who consent for randomization may be a highly selected group of individuals who really have no preference on treatment; thus may limit the assessment of effectiveness. Therefore, we aimed to determine the feasibility of an alternative study design, “the comprehensive cohort study” that can overcome the concerns of conventional RCTs. METHODS: AIS patients aged ≥10 years, had Risser sign between 0-II, and had a Cobb angle of 25° to <30° or 20° to <25° with 5° deterioration over the past 4 months were invited to join a RCT. Those declined were given an option to stay in the study, but choose whether they wish to be braced or observed. A randomization schedule was generated for all patients whether or not they joined the RCT; thus additional patients who made their own choice may also fit with the randomized choices. Blinded out-of-brace radiographic and psychosocial assessments were made. Compliance was assessed. For those without brace but had ≥6° curve progression or reached 30° were considered failures, and braces were offered. Patients were followed every 4 months. RESULTS: Over 1 year, there were 87 eligible patients, 68 (78%) patients (5 boys and 63 girls) with mean age of 12.5 years (range: 10 to 15 years) consented to participate with a median follow-up of 57 weeks. Of which, 19 (28%) patients accepted randomization with respectively 13 and 6 patients allotted to brace and observation. For others who declined randomization, 18 (37%) chose brace and 28 (57%) patients had their choice of treatment the same as that on the randomization schedule. Braced patients had a daily average of over 17 hours within the first year. 10 patients had ≥6° curve progression during follow-up. CONCLUSION: This Comprehensive Cohort Study design has the potential to improve the rate of recruitment such that both efficacy and effectiveness of bracing in AIS can be assessed. Our preliminary study showed that it can be feasibly conducted with less recruitment burden. A larger scale study with longer follow-up is needed to address the question of efficacy and effectiveness of braces.link_to_OA_fulltex

Fine mapping candidate loci for nasopharyngeal carcinoma (NPC) in southern Chinese specifically linked to EBV aetiopathogenesis

Poster Presentation - Cancer: no. Ab169Theme: Improving Health and Recognising ExcellenceRef no. RFCID 08070652Nasopharyngeal carcinoma (NPC) is a malignancy that has nearly 100-fold higher incidence in southern Chinese than in most European populations. NPC clusters in families, which suggests that both geography and …link_to_OA_fulltex