High-efficiency vertically emitting coupler facilitated by three wave interaction gratings.

We designed a grating coupler optimized for normal incidence and numerically demonstrate near-unity coupling in a standard 220-nm-thick silicon-on-insulator (SOI) technology. Our design breaks the vertical symmetry within the grating region by implementing three scattering sites per local period. This technique removes the need for bottom reflectors or additional material layers and can be realized using only two lithography masks. Using adjoint method-based optimization, we engineer the coupling spectrum of the grating, balancing the trade-off between peak efficiency and bandwidth. Using this technique, we simulate three devices with peak coupling efficiencies ranging between 93.4 (-0.3 dB) and 98.6% (-0.06 dB) with corresponding 1 dB bandwidths between 48 and 8 nm all centered around 1.55 µm.

Experimentally realized in situ backpropagation for deep learning in photonic neural networks.

Integrated photonic neural networks provide a promising platform for energy-efficient, high-throughput machine learning with extensive scientific and commercial applications. Photonic neural networks efficiently transform optically encoded inputs using Mach-Zehnder interferometer mesh networks interleaved with nonlinearities. We experimentally trained a three-layer, four-port silicon photonic neural network with programmable phase shifters and optical power monitoring to solve classification tasks using "in situ backpropagation," a photonic analog of the most popular method to train conventional neural networks. We measured backpropagated gradients for phase-shifter voltages by interfering forward- and backward-propagating light and simulated in situ backpropagation for 64-port photonic neural networks trained on MNIST image recognition given errors. All experiments performed comparably to digital simulations ([Formula: see text]94% test accuracy), and energy scaling analysis indicated a route to scalable machine learning.

Experimental realization of arbitrary activation functions for optical neural networks.

We experimentally demonstrate an on-chip electro-optic circuit for realizing arbitrary nonlinear activation functions for optical neural networks (ONNs). The circuit operates by converting a small portion of the input optical signal into an electrical signal and modulating the intensity of the remaining optical signal. Electrical signal processing allows the activation function circuit to realize any optical-to-optical nonlinearity that does not require amplification. Such line shapes are not constrained to those of conventional optical nonlinearities. Through numerical simulations, we demonstrate that the activation function improves the performance of an ONN on the MNIST image classification task. Moreover, the activation circuit allows for the realization of nonlinearities with far lower optical signal attenuation, paving the way for much deeper ONNs.

Automated Cell Segmentation for Quantitative Phase Microscopy.

Automated cell segmentation and tracking is essential for dynamic studies of cellular morphology, movement, and interactions as well as other cellular behaviors. However, accurate, automated, and easy-to-use cell segmentation remains a challenge, especially in cases of high cell densities, where discrete boundaries are not easily discernable. Here, we present a fully automated segmentation algorithm that iteratively segments cells based on the observed distribution of optical cell volumes measured by quantitative phase microscopy. By fitting these distributions to known probability density functions, we are able to converge on volumetric thresholds that enable valid segmentation cuts. Since each threshold is determined from the observed data itself, virtually no input is needed from the user. We demonstrate the effectiveness of this approach over time using six cell types that display a range of morphologies, and evaluate these cultures over a range of confluencies. Facile dynamic measures of cell mobility and function revealed unique cellular behaviors that relate to tissue origins, state of differentiation, and real-time signaling. These will improve our understanding of multicellular communication and organization.

Evaluation of polypharmacy and appropriateness of prescription in geriatric patients: A cross-sectional study at a tertiary care hospital.

OBJECTIVES: To assess the polypharmacy and appropriateness of prescriptions in geriatric patients in a tertiary care hospital. METHODS: An observational study was done in geriatric patients (>60 years) of either gender. The data collected from patients included: Socio-demographic data such as age, gender, marital status, educational status, socioeconomic status, occupation, nutritional status, history of alcohol/smoking, exercise history, details of comorbid diseases, medication history, findings of clinical examination etc. In this study, polypharmacy was considered as having 5 or more medications per prescription. Medication appropriateness for each patient was analysed separately based on their medical history and clinical findings by applying medication appropriateness index, screening tool to alert to right treatment (START) and Beers criteria and STOPP criteria. RESULTS: A total of 426 patients, 216 (50.7%) were males and 210 (49.3%) were females. Polypharmacy was present in 282 prescriptions (66.2%). Highest prevalence of polypharmacy was seen in 70-79 years age group compared to the other two groups and it was statistically significant. Out of 426 patients, 36 patients were receiving drugs which were to be avoided as per Beers criteria. Among the total patients, 39 patients were overprescribed as per MAI, 56 patients were under prescribed as per START criteria and 85 out of 426 prescriptions were inappropriate in accordance with beers criteria, stop criteria, start criteria and MAI index. CONCLUSION: Around 66.19% patients were receiving polypharmacy. Significant number of patients were receiving drugs which are to be avoided as well as overprescribed and under prescribed. Inappropriate prescription was seen in a good number of patients.

Hydroxychloroquine-induced erythroderma.

Erythroderma is characterized by diffuse erythema and scaling of the skin involving more than 90% of the total body skin surface area. Drug-induced erythroderma has rarely been reported with hydroxychloroquine. We report a case of a 50-year-old female patient, with systemic lupus erythematosus, who developed itchy lesions all over the body 1 month after starting treatment with hydroxychloroquine. Drug-induced erythroderma was suspected. Hydroxychloroquine was withdrawn and the patient was treated with emollients, mid-potency corticosteroids, and oral antihistamines. A biopsy was done which confirmed the diagnosis of erythroderma. She recovered with treatment and was discharged. A careful history and clinical examination to search for potential causative factors will help prevent disabling sequelae in erythroderma.

Choosing Between Unicompartmental and Total Knee Replacement: What Can Economic Evaluations Tell Us? A Systematic Review.

BACKGROUND AND OBJECTIVE: Patients with anteromedial arthritis who require a knee replacement could receive either a unicompartmental knee replacement (UKR) or a total knee replacement (TKR). This review has been undertaken to identify economic evaluations comparing UKR and TKR, evaluate the approaches that were taken in the studies, assess the quality of reporting of these evaluations, and consider what they can tell us about the relative value for money of the procedures. METHODS: A search of MEDLINE, EMBASE and the Centre for Reviews and Dissemination National Health Service Economic Evaluation Database was undertaken in January 2016 to identify relevant studies. Study characteristics were described, the quality of reporting and methods assessed using the Consolidated Health Economic Evaluation Reporting Standards (CHEERS) checklist, and study findings summarised. RESULTS: Twelve studies satisfied the inclusion criteria. Five were within-study analyses, while another was based on a literature review. The remaining six studies were model-based analyses. All studies were informed by observational data. While methodological approaches varied, studies generally had either limited follow-up, did not fully account for baseline differences in patient characteristics or relied on previous research that did not. The quality of reporting was generally adequate across studies, except for considerations of the settings to which evaluations applied and the generalisability of the results to other decision-making contexts. In the short-term, UKR was generally associated with better health outcomes and lower costs than TKR. Initial cost savings associated with UKR seem to persist over patients' lifetimes even after accounting for higher rates of revision. For older patients, initial health improvements also appear to be maintained, making UKR the dominant treatment choice. However, for younger patients findings for health outcomes and overall cost effectiveness are mixed, with the difference in health outcomes depending on the lifetime risk of revision and patient outcomes following revision. CONCLUSIONS: UKR appears to be less costly than TKR. For older patients, UKR is also expected to lead to better health outcomes, making it the dominant choice; however, for younger patients health outcomes are more uncertain. Future research should better account for baseline differences in patient characteristics and consider how the relative value of UKR and TKR varies depending on patient and surgical factors.

Standardization and validation of objective structured practical examination in pharmacology: Our experience and lessons learned.

OBJECTIVES: The present study is an attempt to standardize and establish validity and reliability of objective structured practical examination (OSPE) as a tool of assessment in pharmacology. METHODS: The individual stations were standardized by establishing the blueprint of assessment, checklists for individual OSPE stations, and a review and revision of existing OSPE stations through intensive focus group discussions. Face and content validity was established by subject nonexperts and experts, respectively. Internal construct reliability was assessed using Cronbach's alpha. The scores obtained by the students during their formative sessional examinations were analyzed to calculate Cronbach's alpha, a measure of internal construct reliability and Pearson's coefficient of correlation was used to analyze test-retest reliability and interexaminer reliability. Student and faculty feedback were taken using an open-ended questionnaire. RESULTS: The Pearson's coefficient of correlation for inter-rater reliability was 0.985, P = 0.0001. The Pearson's coefficient of correlation for test-retest reliability was 0.967, P = 0.0001. Cronbach's alpha values for first, second, and third sessional examinations were 0.825, 0.724, and 0.798, respectively. CONCLUSION: The faculty and student feedback received was constructive and enabled a systematic review of the existing method and also served as a means to revise the existing curricula.

Spatiotemporal Reconstruction of the Human Blastocyst by Single-Cell Gene-Expression Analysis Informs Induction of Naive Pluripotency.

Human preimplantation embryo development involves complex cellular and molecular events that lead to the establishment of three cell lineages in the blastocyst: trophectoderm, primitive endoderm, and epiblast. Owing to limited resources of biological specimens, our understanding of how the earliest lineage commitments are regulated remains narrow. Here, we examined gene expression in 241 individual cells from early and late human blastocysts to delineate dynamic gene-expression changes. We distinguished all three lineages and further developed a 3D model of the inner cell mass and trophectoderm in which individual cells were mapped into distinct expression domains. We identified in silico precursors of the epiblast and primitive endoderm lineages and revealed a role for MCRS1, TET1, and THAP11 in epiblast formation and their ability to induce naive pluripotency in vitro. Our results highlight the potential of single-cell gene-expression analysis in human preimplantation development to instruct human stem cell biology.

Dynamic and social behaviors of human pluripotent stem cells.

Human pluripotent stem cells (hPSCs) can self-renew or differentiate to diverse cell types, thus providing a platform for basic and clinical applications. However, pluripotent stem cell populations are heterogeneous and functional properties at the single cell level are poorly documented leading to inefficiencies in differentiation and concerns regarding reproducibility and safety. Here, we use non-invasive time-lapse imaging to continuously examine hPSC maintenance and differentiation and to predict cell viability and fate. We document dynamic behaviors and social interactions that prospectively distinguish hPSC survival, self-renewal, and differentiation. Results highlight the molecular role of E-cadherin not only for cell-cell contact but also for clonal propagation of hPSCs. Results indicate that use of continuous time-lapse imaging can distinguish cellular heterogeneity with respect to pluripotency as well as a subset of karyotypic abnormalities whose dynamic properties were monitored.

Hylleraas hydride binding energy: diatomic electron affinities.

Theoretical adiabatic electron affinities are often considered inaccurate because they are referenced to only a single value. Ground state electron affinities for all the main group elements and homonuclear diatomics were identified recently using the normalized binding energy of the hydrogen atom: [0.75420375(3)/2 = 0.37710187(1) eV]. Here we revisit experimental values and extend the identifications to diatomics in the G2-1 set. We assign new ground state electron affinities: (eV) Cl2, 3.2(2); Br2, 2.87(14); CH, 2.1(2); H2, 0.6 ; NH, 1.1, SiH, 1.90. Anion Morse potentials are calculated for H2 and N2 from positive electron affinities and for hyperfine superoxide states for the first time.

Do minimally displaced, closed tibial fractures in children need monitoring for compartment syndrome?

INTRODUCTION: Acute compartment syndrome (ACS) may be seen following tibial fractures in adults. Although the risk of this complication is thought to be lower in children (especially in those under the age of 12 years) it is routine practice in many units to admit all children with this injury for observation. The aim of this study was to ascertain whether all children under the age of 12 presenting with fractures of the tibia merited admission and to provide recommendations on how to manage these patients based on our experience with this injury. PATIENTS AND METHODS: We retrospectively studied the clinical and radiographic progress of consecutive patients presenting to our institution with tibial fractures over a 5-year period. RESULTS: A total of 159 tibial fractures were seen in the study period. The mean age of patients treated was 5.8 years. 81% of the injuries occurred in the diaphyseal region and 60% involved the tibia only. A total of 9% of injuries were open and overall 66% of fractures were managed non-operatively. No cases of ACS were seen. DISCUSSION: Based on our experience we provide a treatment algorithm detailing how children in the under 12 age group presenting with tibial fractures may be managed. Patients with minimally displaced fractures involving the tibia only, whose pain is adequately controlled and who can safely mobilise with suitable parental supervision may be safely discharged from the emergency department in a back slab with early follow up. Although no children under the age of 12 in the present study developed ACS following a fracture of the tibia, certain features such as a history of a high energy injury, displaced fractures or co-existing fibular fractures should raise suspicion that this complication may ensue. In these cases admission and observation may be warranted.

Long-term results of a total knee prosthesis utilising an all polyethylene tibial component.

INTRODUCTION: The aim of this study was to assess the long-term performance of a cemented total knee replacement utilising an All Polyethylene Tibial (APT) component and in addition to perform an engineering analysis of any failures to help refine surgical technique. MATERIALS AND METHODS: A total of 26 patients had a total knee replacement performed using a cemented Depuy Press Fit Condylar (PFC) APT component and a cruciate retaining femoral component. At final review all patients were assessed using The Knee Society Score together with radiographs. An engineering analysis simulated loading conditions of the implants that failed and these were compared with the performance of a modular metal-backed Tibial (MBT) component. RESULTS: A total of 20 patients were reviewed at mean time of 116 months following surgery. Knee Society Knee Scores and Function Scores in this cohort were 84/100 and 58/100, respectively. Two patients required revision for tibial component failure. Pre-operatively both had valgus deformities and in each case the tibial tray had been lateralised leaving a gap on the medial side where the APT component had no rigid support. The engineering analysis demonstrated that the volume of highly strained cancellous bone was greater in the APT design compared with the MBT design when a model with a 3 mm medial gap was loaded. The stiffer MBT base plate acted more rigidly and shielded the stress applied to the proximal tibial cancellous bone. CONCLUSION: The APT component demonstrated satisfactory clinical and radiographic performance at long-term follow up. Appropriate cortical support of the APT component is important. The implant should be used with a degree of caution in patients with severe deformities and osteoporosis.

Osteochondral avulsion fracture of the femoral origin of the anterior cruciate ligament in an 11-year-old child.

Although tibial end avulsions of the anterior cruciate ligament are relatively common in clinical practice, avulsions of the femoral end of this ligament are by comparison rare. We present the case of an 11-year-old boy with a bony avulsion injury, which was presumed to have arisen from the tibial insertion of the anterior cruciate ligament but turned out instead to be an osteochondral avulsion fracture of the femoral origin. This unexpected finding that was not detected during preoperative workup resulted in the first attempt at surgical fixation being aborted. The need for a second planned definitive fixation procedure emphasises the importance of combining a thorough history and examination in association with appropriate imaging in the patient workup. The patient's definitive operative treatment and outcome are described. Although rare, surgeons (and emergency room doctors) treating such patients should include femoral end avulsion injuries of the anterior cruciate ligament in the differential diagnosis of a child presenting with an acute haemarthrosis of the knee. Furthermore, once diagnosed, early onward referral to an experienced knee surgeon is advocated.

Elective open tracheostomy for patients under prolonged mechanical ventilation-a study.

OBJECTIVE: To determine the safety of elective open tracheostomy as a routine intensive care unit (ICU) procedure without any selection criteria, considering its peri- and postoperative complications. MATERIALS AND METHODS: This is a descriptive study conducted in two hospitals in Davangere for a period of three years between April 2005 and March 2008. 40 patients, both male and female, of all age groups who were under mechanical ventilation in whom open tracheostomy was performed were included in the study. All patients who recovered were followed-up for two months. Complications arising during this period were recorded in the proforma. RESULTS: Our study consisted of 40 patients comprising 30 males and 10 females with male to female ratio of 3:1 and average age of 35 years, all undergoing open tracheostomy for prolonged mechanical ventilation. Various indications for mechanical ventilation included polytrauma, head injury, septicemia with multiorgan failure and dengue encephalitis. The complications which arised during the procedure and follow-up period included cardiac arrest, surgical emphysema, reactionary hemorrhage, pneumothorax, tracheo-cutaneous fistula, tracheo-oesophageal fistula. CONCLUSION: Elective open tracheostomy seems to be a safe and simple procedure, when performed by experienced surgeon under controlled circumstances, and should be considered as an option for mechanically ventilated patients.

Delayed anatomical repair of ruptured ulnar collateral ligament injuries of the thumb using a dissolvable polylactic acid bone anchor.

BACKGROUND: We describe late anatomic repair of complete distal ulnar collateral ligament (UCL) avulsions of the thumb in the absence of metacarpophalangeal joint arthritis using a dissolvable polylactic acid (PLA) bone anchor in two cases, one of which had a Stener lesion. METHODS: Patients presented for surgery respectively at 5 months and 2 years after injury. Preoperative X-ray films showed subtle volar subluxation of the proximal phalanx. Volar plate release corrected this in both cases and a transarticular k-wire was not used. Satisfactory repair was achieved in both cases using a dissolvable PLA bone anchor. Flexion-extension mobilization was supervised by a hand therapist from day 1 after surgery. A low profile radial-sided thermoplastic splint to prevent reinjury of the UCL repair was used allowing interphalangeal joint and base of thumb movement, and was worn between therapy sessions for 4 weeks. RESULTS: In both patients, satisfactory UCL stability was maintained at 3-year follow-up after surgery. DISCUSSION: Dissolvable PLA bone anchors may be used to satisfactorily restore stability and function in late presenting complete distal UCL avulsions of the thumb with or without accompanying Stener lesions.

The Glance software package.

We describe the Glance software package, which takes advantage of tablet PC technology to control experiments that require participants to reconstruct complex stimuli, as with the Chase and Simon (1973) chess reconstruction task, and to present tests that require participants to refer briefly to critical displays, as with the digit-symbol task. Participants press the space bar, which allows access to the stimulus and, simultaneously, prohibits drawing on the tablet. At release of the space bar--or optionally, after some period of time--the stimulus is hidden, and the drawing tools are enabled. Output from Glance allows analysis as fine grained as each stroke or as coarse as the entire image.

Presentation and management of arthritis affecting the trapezio-metacarpal joint.

Arthritis affecting the trapezio-metacarpal joint (TMJ) of the thumb is a very common condition, and in the upper limb represents the site most often requiring surgery for symptomatic osteoarthritis. The condition predominantly affects women, especially those who are post menopausal. Management of the condition initially entails the use of conservative measures. Many of these are administered in the community by general practitioners as well as occupational therapists, surgery being reserved for disabling symptoms and loss of function resistant to these measures. From a review of the currently available literature, we present an overview of this common condition, commenting on its clinical presentation, pathophysiology and the treatment options available. A treatment algorithm is presented, to aid practitioners in the management and referral of patients with symptomatic thumb TMJ arthritis.