Electromagnetic design search and optimisation of photonic bandgap devices on distributed computational resources

Photonic crystals are devices with periodically modulated dielectric constant, designed to exhibit band gaps in a frequency spectrum in which electromagnetic waves cannot propagate. Tuning the properties of these structures to achieve precise band gaps before fabrication is of high interest to photonic crystal manufacturers. In this paper, we present the process of finding and optimising a photonic crystal design using a high-throughput Condor-based compute cluster and transparent database technology for easy storage, retrieval and reuse of the created designs. We also demonstrate how a band gap diagram can easily be obtained on a compute cluster when using the developed user interface technology. The optimisation process can easily be adapted to other problem area

Should eye protection be worn during dermatological surgery: prospective observational study

Background There is a potential risk of infection with blood-borne viruses if a doctor receives a blood splash to a mucous membrane. The quantification of facial contamination with blood has never been documented in the context of dermatological surgery. Objectives (i) To identify the number of facial blood splashes that occur during skin surgery and to identify the procedures that present higher risks for the operator and assistant. (ii) To assess the provision of eye protection and attitudes to its use in dermatological surgery in the U.K. Methods (i) Prospective, observational study in the skin surgery suite of a U.K. teaching hospital assessing 100 consecutive dermatological surgery procedures, plus 100 consecutive operations in which an assistant was present. Primary outcome: number of face-mask visors with at least one blood splash. Secondary outcomes: to identify if any of the following variables influenced the occurrence of a blood splash: grade of operator, site and type of procedure, and the use of electrocautery. (ii) A postal survey of all U.K.-based members of the British Society of Dermatological Surgery (BSDS) was conducted assessing facilities available and the attitudes of U.K.-based clinicians to the use of face masks during surgery. Results (i) In 33% of all surgical procedures there was at least one facial splash to the operator (range 1–75) and in 15% of procedures the assistant received at least one splash (range 1–11). Use of monopolar electrocautery was significantly less likely to result in splashes to the mask compared with bipolar electrocautery [odds ratio (OR) 0Æ04; 95% confidence interval (CI) 0Æ01–0Æ19]. Compared with the head/neck, operations on the body were significantly more likely to result in splashes to the mask (OR 6Æ52) (95% CI 1Æ7–25Æ07). The type of procedure and the status of the operator did not have a bearing on the likelihood of receiving a splash to the mask. (ii) From the survey, 33 of 159 (20Æ8%) of BSDS members had no face masks available and 54 of 159 (34Æ0%) did not wear any facial protection while operating. The majority (53Æ5%) thought they received a splash in £ 1% of procedures. Conclusions There is a substantial risk of a splash of blood coming into contact with the face during dermatological surgery for both the operator and assistant, regardless of the procedure. The risk of receiving a blood splash to the face may be substantially underestimated by U.K.-based dermatologists. The use of protective eyewear is advisable at all times, but particularly when using bipolar electrocautery, or when operating on high-risk individuals

Prophylactic antibiotics for the prevention of cellulitis

Background: Cellulitis of the lower leg accounts for 2-3% of hospital admissions (Cox et al, 1998), with an average length of in-patient stay of nine days. Studies have reported that up to half of these patients suffer further episodes (Cox et al, 1998; Dupuy et al, 1999). Reducing the recurrence of cellulitis could therefore have a significant impact on both patient morbidity and NHS costs. Aims: To assess whether prophylactic antibiotics prescribed after an episode of cellulitis of the leg results in fewer subsequent attacks and reduced health service costs (PATCH prophylactic antibiotics for the treatment of cellulitis at home). Methods: This article describes two related studies in which participants are randomised to receive either 12 months of prophylaxis (PATCH I) or six months of prophylaxis (PATCH II). The PATCH I study recruits only patients with recurrent disease defined as two or more episodes of cellulitis in the last three years. PATCH II has more open criteria and includes patients with a first episode of cellulitis and also participants with recurrent disease. It is expected that 260 patients will be recruited into PATCH I and 400 patients into PATCH II

Conservation of structure and mechanism in primary and secondary transporters exemplified by SiaP, a sialic acid binding virulence factor from Haemophilus influenzae

Extracytoplasmic solute receptors (ESRs) are important components of solute uptake systems in bacteria, having been studied extensively as parts of ATP binding cassette transporters. Herein we report the first crystal structure of an ESR protein from a functionally characterized electrochemical ion gradient-dependent secondary transporter. This protein, SiaP, forms part of a tripartite ATP-independent periplasmic transporter specific for sialic acid in Haemophilus influenzae. Surprisingly, the structure reveals an overall topology similar to ATP binding cassette ESR proteins, which is not apparent from the sequence, demonstrating that primary and secondary transporters can share a common structural component. The structure of SiaP in the presence of the sialic acid analogue 2,3-didehydro-2-deoxyN-acetylneuraminic acid reveals the ligand bound in a deep cavity with its carboxylate group forming a salt bridge with a highly conserved Arg residue. Sialic acid binding, which obeys simple bimolecular association kinetics as determined by stopped-flow fluorescence spectroscopy, is accompanied by domain closure about a hinge region and the kinking of an alpha-helix hinge component. The structure provides insight into the evolution, mechanism, and substrate specificity of ESR-dependent secondary transporters that are widespread in prokaryotes

Early recognition and detection of juvenile psoriatic arthritis: a call for a standardized approach to screening

Background: National Institute for Health and Care Excellence (NICE) guidelines recommend annual screening for psoriatic arthritis (PsA) in all patients with psoriasis. Currently, no validated assessment tools have been recommended for screening for juvenile PsA (JPsA). Aim: To determine dermatologists' practice when assessing children's joints and explore the challenges dermatologists experience when looking for joint disease, in order to inform future strategies to improve early detection of arthritis. Methods: Structured telephone interviews were undertaken with dermatologists identified through the British Society of Paediatric Dermatology. Percentages for binary and categorized responses were calculated. Thematic content analysis was used to generate a set of core themes across the interview data. Results: Of the 41 consultant dermatologists contacted, 23 agreed to be interviewed. Of these, 78% (18/23) reported they routinely ask about joint disease. Only 13% (3/23) routinely examine the joints of children with psoriasis. Overall, assessment for JPsA lacked a structured, evidence-based approach. The average confidence rating for assessing joint disease was low (score of 3). The two key barriers described for detecting arthritis were a lack of experience and training, and subtle or difficult to detect signs. The two main suggestions for improving detection were the introduction of an assessment tool/guideline and increased clinical experience and training. Conclusion: There is a clear need for dermatologists to use a standardized approach for screening and to increase their confidence in paediatric musculoskeletal examination. In this article, we provide guidance on screening for psoriatic arthritis in children based on our clinical experience

The views of children and young people on the use of silk garments for the treatment of eczema: a nested qualitative study within the CLOTHES randomised controlled trial

Background: Many children suffer with skin diseases, but to date, most dermatological research has been done ‘on’ rather than ‘with’ children; in this study we actively sought the experiences of children and young people. Atopic eczema (AE) is a chronic, itchy, inflammatory skin condition that affects around 20% of children and can impact on health and wellbeing for children and their families. The role of specialist clothing in the management of AE is poorly understood. Objectives: The aim of this study, which was nested in a randomised controlled trial was to qualitatively examine child participants’ experiences of using silk garments for the treatment of AE. Methods: Eighteen children aged 5-15, who took part in the CLOTHES trial, participated in age-appropriate individual interviews or focus groups. Results: Thematic analysis generated 4 themes directly related to the garments: i) expectations of the garments; ii) wearing the silk garments; iii) did they help? and iv) thoughts about the garments. The conclusions from this nested qualitative study are that: there was some limited improvement in eczema for some children but that the hoped for ‘miracle cure’ did not transpire. A mixed picture of knowledge, beliefs and experiences of using the silk garments emerged. Conclusion: Engaging children in the evaluation of the garments provided first hand nuanced insights that enhanced understanding of the CLOTHES study as a whole. This nested study demonstrates that children can and indeed want to be engaged in dermatological research in meaningful ways that add to our understanding of treatment options

A geometry optimization framework for photonic crystal design

AbstractThe performance of photonic crystal devices can depend strongly on their geometry. Alas, their fundamental physics offers relatively little by way of pointers in terms of optimum shapes, so numerical design search techniques must be used in an attempt to determine high performance layouts. We discuss strategies for solving this type of optimization problem, the main challenge of which is the conflict between the enormous size of the space of potentially useful designs and the relatively high computational cost of evaluating the performance of putative shapes. The optimization technique proposed here operates over increasing levels of fidelity, both in terms of the resolution of its non-parametric shape definition and in terms of the resolution of the numerical analysis of the performance of putative designs. This is a generic method, potentially applicable to any type of electromagnetic device shape design problem. We also consider a methodology for assessing the robustness of the optima generated through this process, investigating the impact of manufacturing errors on their performance. As an illustration, we apply this technology to the design of a two-dimensional photonic crystal structure; the result features a large complete band gap structure and a topology that is different from previously published designs

High speed synchrotron X-ray imaging studies of the ultrasound shockwave and enhanced flow during metal solidification processes

The highly dynamic behaviour of ultrasonic bubble implosion in liquid metal, the multiphase liquid metal flow containing bubbles and particles, and the interaction between ultrasonic waves and semisolid phases during solidification of metal were studied in situ using the complementary ultrafast and high speed synchrotron X-ray imaging facilities housed respectively at the Advanced Photon Source, Argonne National Laboratory, US, and Diamond Light Source, UK. Real-time ultrafast X-ray imaging of 135,780 frames per second (fps) revealed that ultrasonic bubble implosion in a liquid Bi-8 wt. %Zn alloy can occur in a single wave period (30 kHz), and the effective region affected by the shockwave at implosion was 3.5 times the original bubble diameter. Furthermore, ultrasound bubbles in liquid metal move faster than the primary particles, and the velocity of bubbles is 70 ~ 100% higher than that of the primary particles present in the same locations close to the sonotrode. Ultrasound waves can very effectively create a strong swirling flow in a semisolid melt in less than one second. The energetic flow can detach solid particles from the liquid-solid interface and redistribute them back into the bulk liquid very effectively

Protocol for a case-control diagnostic accuracy study to develop diagnostic criteria for psoriasis in children (DIPSOC study): a multicentre study recruiting in UK paediatric dermatology clinics

Introduction Diagnosing psoriasis in children can be challenging. Early and accurate diagnosis is important to ensure patients receive psoriasis specific treatment and monitoring. It is recognised that the physical, psychological, quality of life, financial and comorbid burden of psoriasis are significant. The aim of this study is to develop clinical examination and history-based diagnostic criteria for psoriasis in children to help differentiate psoriasis from other scaly inflammatory rashes. The criteria tested in this study were developed through a consensus study with a group of international psoriasis experts (International Psoriasis Council). Methods and analysis Children and young people (<18 years) with psoriasis (cases) and other scaly inflammatory skin diseases (controls) diagnosed by a dermatologist are eligible for recruitment. All participants complete a single research visit including a diagnostic criteria assessment by a trained investigator blinded to the participant’s diagnosis. The reference standard of a dermatologist’s diagnosis is extracted from the medical record. Sensitivity and specificity of the consensus derived diagnostic criteria will be calculated and the best predictive criteria developed using multivariate logistic regression. Ethics and dissemination Health Regulatory Authority and National Health Service Research Ethics Committee approvals were granted in February 2017 (REC Ref: 17/ EM/0035). Dissemination will be guided by stakeholders; patients, children and

de-Broglie Wave-Front Engineering

We propose a simple method for the deterministic generation of an arbitrary continuous quantum state of the center-of-mass of an atom. The method's spatial resolution gradually increases with the interaction time with no apparent fundamental limitations. Such de-Broglie Wave-Front Engineering of the atomic density can find applications in Atom Lithography, and we discuss possible implementations of our scheme in atomic beam experiments.Comment: The figures' quality was improved, the text remains intact. 5 pages, 3 figures; submitted to PR