337 research outputs found

    Cavity Mode Frequencies and Strong Optomechanical Coupling in Two-Membrane Cavity Optomechanics

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    We study the cavity mode frequencies of a Fabry-P\'erot cavity containing two vibrating dielectric membranes. We derive the equations for the mode resonances and provide approximate analytical solutions for them as a function of the membrane positions, which act as an excellent approximation when the relative and center-of-mass position of the two membranes are much smaller than the cavity length. With these analytical solutions, one finds that extremely large optomechanical coupling of the membrane relative motion can be achieved in the limit of highly reflective membranes when the two membranes are placed very close to a resonance of the inner cavity formed by them. We also study the cavity finesse of the system and verify that, under the conditions of large coupling, it is not appreciably affected by the presence of the two membranes. The achievable large values of the ratio between the optomechanical coupling and the cavity decay rate, g/Îşg/\kappa, make this two-membrane system the simplest promising platform for implementing cavity optomechanics in the strong coupling regime.Comment: Contribution to the special issue on "Nano-optomechanics" in Journal of Optics, edited by I. Wilson-Rae, J. Sankey and H. Offerhau

    Skin grafts : local quest for viable alternatives to autologous grafts using silk and acellular dermal matrices

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    The gold standard with regards to skin transplantation is the use of the patient’s own skin obtained from a healthy donor site. Such grafts can be either full thickness skin or more commonly nowadays, split thickness skin. Various materials, having either natural and or synthetic origins, have been used in the engineering of skin substitutes to-date and these grafts are then confronted against autologous skin grafts. If proven to be successful, such matrices could be utilised in clinical applications such as in the treatment of burn wounds and in cases of skin ulcers amongst others. In this study the primary cells used, keratinocytes and fibroblast, were obtained from donor skin and cultured. Scaffolds of xenogenic (raw silk) as well as of allogenic (acellular dermal matrices) origins were obtained via low-cost methods and seeded using the fibroblasts and keratinocytes so as to determine which gave the closest mimic to skin grafts. Out of the matrices assessed, the raw silk matrix allowed the best colonisation with skin cells in our hands. The ADM matrice also showed some cell colonisation, but will need further experimentation.peer-reviewe

    Spontaneous remission in the ahumada : del castillo syndrome

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    The association of spontaneous galactorrhea with primary or secondary amenorrhea is a striking clinical picture and has increasingly engaged the attention of clinicians as, during the past two decades, numerous and diverse etiological factors have been incriminated. Much stress has been laid in the past on the persistence and intractability of symptoms in patients belonging to the group originally described by Ahumada and del Castillo (1932). A case study of a thirty-year-old nulliparous woman, who gave a history of six months amenorrhea and had noticed spontaneous ejection of milky fluid from the breasts in the latter three months is reported and discussed. The patient's clinical picture coincides with the group often known as belonging to the Ahumada-del Castillo. In this case the patient stopped lactating spontaneously shortly after her acute renal illness. One can rule out that this was solely due to the stopping of hypotensive drugs as the galactorrhea and amenorrhea antedated by months the use of any drug. It is the objective of this article to indicate that the syndrome of idiopathic galactorrhea and amenorrhea need not necessarily have a poor therapeutic prognosis but may show spontaneous remission.peer-reviewe

    Patients’ and health professionals’ views and experiences of atrial fibrillation and oral-anticoagulant therapy:a qualitative meta-synthesis

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    Objective - Atrial fibrillation (AF) patients are prescribed oral-anticoagulant (OAC) therapy, often warfarin, to reduce stroke risk. We explored existing qualitative evidence about patients’ and health professionals’ experiences of OAC therapy. Methods - Systematic searches of eight bibliographic databases were conducted. Quality was appraised using the Critical Appraisal Skills Programme tool and data from ten studies were synthesised qualitatively. Results - Four third-order constructs, emerged from the final step in the analysis process: (1) diagnosing AF and the communication of information, (2) deciding on OAC therapy, (3) challenges revolving around patient issues, and (4) healthcare challenges. Synthesis uncovered perspectives that could not be achieved through individual studies. Conclusion - Physicians’ and patients’ experiences present a dichotomy of opinion on decision-making, which requires further exploration and changes in practice. Outcomes of workload pressure on both health professionals and patients should be investigated. The need for on-going support and education to patients and physicians is critical to achieve best practice and treatment adherence. Practice implications - Such research could encourage health professionals to understand and attend better to the needs and concerns of the patient. Additionally these findings can be used to inform researchers and healthcare providers in developing educational interventions with both patients and health professionals

    Pyogenic granuloma as a surrogate indicator of deep seated foreign bodies: a case report

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    Although pyogenic granulomas are often clinically associated with foreign bodies or recurrent traumatic injury, this association is not well documented. We report a case of a recurrent, intractable pyogenic granuloma due to a missed foreign body. An extensive search retrieved no previous literature reporting this association. This lack of evidence bases may hinder the hand surgeon from extending the wound incision and thorough exploration. Recurrent pyogenic granulomas should lead the hand surgeon to entertain the possibility of a missed foreign body

    Variants within protectin (CD59) and CD44 genes linked to an inherited haplotype in a family with coeliac disease

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    Coeliac disease (CD) is an autoimmune disorder characterised by inflammation, villous atrophy and hyperplasia of the small intestinal mucosa that affects genetically susceptible individuals. A genome-wide scan was performed in 17 family members with high incidence of CD. Highest nonparametric linkage (NPL) and logarithm of odds (LOD) scores were of 6.21 (P = 0.0107) and 2.57, respectively, to a region on chromosome 11p13-12. Following fine mapping, NPL and LOD scores did not change, but the linkage interval on chromosome 11 was narrowed to a region that is approximately 50.94 cM from pTer. Two inherited haplotypes on chromosomes 11p13-12 and 9q21 were observed in all affected members but not in the majority of clinically normal individuals. Sequencing of genes at region 11p13-12 showed a number of sequence variants, two of which were linked with the inherited haplotype. One of these variants in the CD59 gene was found at a very low frequency in the population and could possibly affect pre-messenger RNA splicing. This study is of particular importance for the identification of novel genes that might be responsible for CD other than human leukocyte antigen.peer-reviewe

    Antiplatelet and anticoagulant therapy for non-ST-elevation acute coronary syndromes in a general hospital

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    Aim: To audit compliance with the 2011 European Society of Cardiology (ESC) guidelines for prescribing antiplatelet and anticoagulant therapy in patients diagnosed with non-ST-elevation acute coronary syndromes (NSTE-ACS). Methods: Five-month audit at Cardiac Catheterisation Suite, Mater Dei Hospital, Malta. A data collection form for inpatients diagnosed with NSTE-ACS was developed, psychometrically evaluated and completed for each patient by the investigator. Comparative analysis to assess whether these patients were being managed according to the guidelines was undertaken. Results: 165 patients were recruited; 73% were male, 37% were between 66 and 75 years and 44% were active smokers. The most common risk factors for cardiovascular disease in these patients were hypertension (27%), dyslipidemia and obesity (both 16%). 41% of the patients underwent a percutaneous coronary intervention, either ad hoc (34%) or elective (7%). Compliance to guidelines for prescription of aspirin and clopidogrel 300mg loading dose was 95% and 88% respectively. Compliance to guidelines for prescription of aspirin and clopidogrel 75mg daily maintenance dose was 97% and 96% respectively. Compliance to guidelines for prescription of proton pump inhibitors (PPIs) in patients receiving dual antiplatelet therapy (DAPT) was only 19%; 81% of the patients were prescribed omeprazole against guideline recommendations. Compliance to guidelines for prescription of anticoagulation therapy was 95% with respect to prescription of heparin treatment in combination with DAPT. Compliance to guidelines for prescription of enoxaparin was 81%. Compliance to guidelines for other antiplatelet and anticoagulant drugs recommended in the guidelines, including ticagrelor, prasugrel, glycoprotein IIb/IIIa receptor antagonists, fondaparinux and bivalirudin, was not measured. Conclusions: Prescription of antiplatelet and anticoagulant therapy for NSTE-ACS in Malta is predominantly in accordance with ESC guidelines. Alternative antiplatelet and anticoagulant drugs and PPIs should be included in the Maltese hospital formulary to improve NSTE-ACS management in line with guideline recommendations.peer-reviewe

    Optomechanics for quantum technologies

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    The ability to control the motion of mechanical systems through interaction with light has opened the door to a plethora of applications in fundamental and applied physics. With experiments routinely reaching the quantum regime, the focus has now turned towards creating and exploiting interesting non-classical states of motion and entanglement in optomechanical systems. Quantumness has also shifted from being the very reason why experiments are constructed to becoming a resource for the investigation of fundamental physics and the creation of quantum technologies. Here, by focusing on opto- and electromechanical platforms we review recent progress in quantum state preparation and entanglement of mechanical systems, together with applications to signal processing and transduction, quantum sensing and topological physics, as well as small-scale thermodynamics

    Educational and behavioural interventions for anticoagulant therapy in patients with atrial fibrillation

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    Background Current guidelines recommend oral anticoagulation therapy for patients with atrial fibrillation who are at moderate-to-high risk of stroke, however anticoagulation control (time in therapeutic range (TTR)) is dependent on many factors. Educational and behavioural interventions may impact on patients’ ability to maintain their International Normalised Ratio (INR) control. Objectives To evaluate the effects on TTR of educational and behavioural interventions for oral anticoagulation therapy (OAT) in patients with atrial fibrillation (AF). Search methods We searched the Cochrane Central Register of Controlled Trials (CENTRAL) and the Database of Abstracts of Reviews of Effects (DARE) in The Cochrane Library (2012, Issue 7 of 12), MEDLINE Ovid (1950 to week 4 July 2012), EMBASE Classic + EMBASE Ovid (1947 to Week 31 2012), PsycINFO Ovid (1806 to 2012 week 5 July) on 8 August 2012 and CINAHL Plus with Full Text EBSCO (to August 2012) on 9 August 2012. We applied no language restrictions. Selection criteria The primary outcome analysed was TTR. Secondary outcomes included decision conflict (patient's uncertainty in making health-related decisions), percentage of INRs in the therapeutic range, major bleeding, stroke and thromboembolic events, patient knowledge, patient satisfaction, quality of life (QoL), and anxiety. Data collection and analysis The two review authors independently extracted data. Where insufficient data were present to conduct a meta-analysis, effect sizes and confidence intervals (CIs) of the included studies were reported. Data were pooled for two outcomes, TTR and decision conflict. Main results Eight trials with a total of 1215 AF patients (number of AF participants included in the individual trials ranging from 14 to 434) were included within the review. Studies included education, decision aids, and self-monitoring plus education. For the primary outcome of TTR, data for the AF participants in two self-monitoring plus education trials were pooled and did not favour self-monitoring plus education or usual care in improving TTR, with a mean difference of 6.31 (95% CI -5.63 to 18.25). For the secondary outcome of decision conflict, data from two decision aid trials favoured usual care over the decision aid in terms of reducing decision conflict, with a mean difference of -0.1 (95% CI -0.2 to -0.02). Authors' conclusions This review demonstrated that there is insufficient evidence to draw definitive conclusions regarding the impact of educational or behavioural interventions on TTR in AF patients receiving OAT. Thus, more trials are needed to examine the impact of interventions on anticoagulation control in AF patients and the mechanisms by which they are successful. It is also important to explore the psychological implications for patients suffering from this long-term chronic condition
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