Experimental Characterisation of Moreno Cross Slot Couplers for Blass Matrix Design

This paper presents the experimental characterisation of Moreno cross-slot coupler which is the basic building block of multiple beam forming network (Blass matrix). The lack of exact theory of such coupler requires extensive experimental evaluation. A novel test jig has been designed, fabricated and tested for this purpose. The experimental results for different scattering parameters are presented

Streak camera based SLR receiver for two color atmospheric measurements

To realize accurate two-color differential measurements, an image digitizing system with variable spatial resolution was designed, built, and integrated to a photon-counting picosecond streak camera, yielding a temporal scan resolution better than 300 femtosecond/pixel. The streak camera is configured to operate with 3 spatial channels; two of these support green (532 nm) and uv (355 nm) while the third accommodates reference pulses (764 nm) for real-time calibration. Critical parameters affecting differential timing accuracy such as pulse width and shape, number of received photons, streak camera/imaging system nonlinearities, dynamic range, and noise characteristics were investigated to optimize the system for accurate differential delay measurements. The streak camera output image consists of three image fields, each field is 1024 pixels along the time axis and 16 pixels across the spatial axis. Each of the image fields may be independently positioned across the spatial axis. Two of the image fields are used for the two wavelengths used in the experiment; the third window measures the temporal separation of a pair of diode laser pulses which verify the streak camera sweep speed for each data frame. The sum of the 16 pixel intensities across each of the 1024 temporal positions for the three data windows is used to extract the three waveforms. The waveform data is processed using an iterative three-point running average filter (10 to 30 iterations are used) to remove high-frequency structure. The pulse pair separations are determined using the half-max and centroid type analysis. Rigorous experimental verification has demonstrated that this simplified process provides the best measurement accuracy. To calibrate the receiver system sweep, two laser pulses with precisely known temporal separation are scanned along the full length of the sweep axis. The experimental measurements are then modeled using polynomial regression to obtain a best fit to the data. Data aggregation using normal point approach has provided accurate data fitting techniques and is found to be much more convenient than using the full rate single shot data. The systematic errors from this model have been found to be less than 3 ps for normal points

Test results from LAGEOS-2 optical characterization using pulsed lasers

The Laser Geodynamic Satellite-2 (LAGEOS-2) has undergone extensive optical testing at NASA Goddard Space Flight Center during 1989. The techniques included measuring the far field diffraction pattern using cw and pulsed lasers. In the pulsed measurement technique, response of the satellite was studied by measuring the far-field diffraction pattern (FFDP) as a function of pulsewidth, wavelength, polarization, position in the FFDP, detector/processing techniques, and satellite orientation. The purpose of the pulsed laser testing was two-fold: (1) to characterize the satellite optical response with the detector and signal processing electronics currently used in most SLR stations using the portable laser ranging standard, and (2) to characterize the satellite response for various conditions using the highest bandwidth optical detector (streak camera) available for the next generation of satellite laser ranging (SLR) technology. The portable ranging standard employed multiple measurement devices and an optical calibration scheme to eliminate range-dependent and amplitude-dependent systematics. These precautions were taken to eliminate/minimize instrumental errors and provide maximum accuracy. For LAGEOS orbit (6000 Km), ground stations are located 34 to 38 Mu radians off the axis of the return signal from the satellite; therefore, an optical mask was used to restrict the field of view (FOV) of detection to this annular region of the FFDP. The two measurement techniques were implemented using an aperture sharing scheme and complemented each other by providing mutual verification

Maxillomandibular Advancement in the Management of Obstructive Sleep Apnea

Maxillomandibular advancement (MMA) is a surgical option for obstructive sleep apnea (OSA). MMA involves forward-fixing the maxilla and mandible approximately 10  mm via Le Fort I maxillary and sagittal split mandibular osteotomies. We retrospectively reviewed outcomes from 24 consecutive OSA patients who underwent MMA at our institution. MMA resulted in an 83% reduction in the group mean apnea-hypopnea index (AHI) per polysomnography an average of 6.7 months after surgery. Forty-two percent of patients achieved a post-MMA AHI of less than 5 events/hour sleep and 71% achieved an AHI less than or equal to 10 events/hour sleep. The Epworth Sleepiness Scale score decreased by an average of 5 post-surgery. No parameters predictive of cure for OSA by MMA were identified

Improving PIC-DSMC Simulations of RF Plasmas via Event Splitting

Particle-in-Cell Direct Simulation Monte Carlo (PIC-DSMC) is a widely used method for simulation of non-equilibrium plasmas, especially when the plasma flow is rarefied, and the applicability of fluid models is questionable. However, the PIC-DSMC method is subject to stochastic noise, and depending on the process being simulated, might require extremely large computational efforts. Therefore, the improvement of accuracy of PIC-DSMC methods is a topic of active research. In the present work, a recently developed collision and boundary condition treatment scheme, dubbed 'event splitting', which aims at improving simulation of low-probability processes, is applied to ionization processes in xenon and helium plasmas, where it shown to reduce the level of stochastic noise compared to standard DSMC collision schemes

Development of a United Kingdom-centric cost-effectiveness model for denture cleaning strategies

Statement of problem Denture stomatitis is a prevalent condition in denture wearers. Economic evaluations of health care can help stakeholders, including patients, make better decisions about treatments for a given condition. Economic models to assess the costs and benefits of different options for managing denture stomatitis are lacking. Purpose The purpose of this study was to explore the feasibility of developing a cost-effectiveness model to assess denture cleaning strategies aimed at preventing denture stomatitis from a denture-wearer perspective in the United Kingdom. Material and methods A model was developed to identify and estimate the costs and effects associated with 3 denture cleaning strategies. These were low care (LC)—cleaning by brushing and soaking overnight in water; medium care (MC)—brushing with toothpaste and soaking overnight in water; and optimum care (OC)—brushing and soaking overnight in water and antimicrobial denture cleanser. Costs, outcome measures (denture stomatitis–free days), and probabilities (incidence of stomatitis, unscheduled dentist visits, prescription charges, self-medication) associated with each strategy were defined. A sensitivity analysis was used to identify key drivers and test the robustness of the model. Results The model showed that the total costs for 2015 ranged from £1.07 (LC) to £18.42 (OC). Costs associated with LC were derived from unscheduled dentist visits and use of medication and/or prescription charges. Incremental costs per denture stomatitis–free day were £0.64 (MC) and £1.81 (OC) compared with LC. A sensitivity analysis showed that varying either or both key parameters (baseline incidence of denture stomatitis and relative effectiveness of MC and OC strategies) had a substantial effect. Incremental cost-effectiveness ratios ranged from £4.11 to £7.39 (worst-case scenario) and from £0.21 to £0.61 (best-case scenario). Conclusions A model was developed to assess the relative cost-effectiveness of different denture cleaning strategies to help improve denture hygiene. An important finding of the study was the lack of evidence on the relative effectiveness of different cleaning strategies, meaning that several assumptions had to be incorporated into the model. The model output would therefore likely be considerably improved and more robust if these evidence gaps were filled

Gastric Alimetry® test interpretation in gastroduodenal disorders : review and recommendations

Chronic gastroduodenal symptoms are prevalent worldwide, and there is a need for new diagnostic and treatment approaches. Several overlapping processes may contribute to these symptoms, including gastric dysmotility, hypersensitivity, gut–brain axis disorders, gastric outflow resistance, and duodenal inflammation. Gastric Alimetry® (Alimetry, New Zealand) is a non-invasive test for evaluating gastric function that combines body surface gastric mapping (high-resolution electrophysiology) with validated symptom profiling. Together, these complementary data streams enable important new clinical insights into gastric disorders and their symptom correlations, with emerging therapeutic implications. A comprehensive database has been established, currently comprising > 2000 Gastric Alimetry tests, including both controls and patients with various gastroduodenal disorders. From studies employing this database, this paper presents a systematic methodology for Gastric Alimetry test interpretation, together with an extensive supporting literature review. Reporting is grouped into four sections: Test Quality, Spectral Analysis, Symptoms, and Conclusions. This review compiles, assesses, and evaluates each of these aspects of test assessment, with discussion of relevant evidence, example cases, limitations, and areas for future work. The resultant interpretation methodology is recommended for use in clinical practice and research to assist clinicians in their use of Gastric Alimetry as a diagnostic aid and is expected to continue to evolve with further development

Release of cellular tension signals self-restorative ventral lamellipodia to heal barrier micro-wounds

Basic mechanisms by which cellular barriers sense and respond to integrity disruptions remain poorly understood. Despite its tenuous structure and constitutive exposure to disruptive strains, the vascular endothelium exhibits robust barrier function. We show that in response to micrometer-scale disruptions induced by transmigrating leukocytes, endothelial cells generate unique ventral lamellipodia that propagate via integrins toward and across these “micro-wounds” to close them. This novel actin remodeling activity progressively healed multiple micro-wounds in succession and changed direction during this process. Mechanical probe-induced micro-wounding of both endothelia and epithelia suggests that ventral lamellipodia formed as a response to force imbalance and specifically loss of isometric tension. Ventral lamellipodia were enriched in the Rac1 effectors cortactin, IQGAP, and p47Phox and exhibited localized production of hydrogen peroxide. Together with Apr2/3, these were functionally required for effective micro-wound healing. We propose that barrier disruptions are detected as local release of isometric tension/force unloading, which is directly coupled to reactive oxygen species–dependent self-restorative actin remodeling dynamics

HIV-1 Protease, Reverse Transcriptase, and Integrase Variation

ABSTRACT HIV-1 protease (PR), reverse transcriptase (RT), and integrase (IN) variability presents a challenge to laboratories performing genotypic resistance testing. This challenge will grow with increased sequencing of samples enriched for proviral DNA such as dried blood spots and increased use of next-generation sequencing (NGS) to detect low-abundance HIV-1 variants. We analyzed PR and RT sequences from >100,000 individuals and IN sequences from >10,000 individuals to characterize variation at each amino acid position, identify mutations indicating APOBEC-mediated G-to-A editing, and identify mutations resulting from selective drug pressure. Forty-seven percent of PR, 37% of RT, and 34% of IN positions had one or more amino acid variants with a prevalence of ≥1%. Seventy percent of PR, 60% of RT, and 60% of IN positions had one or more variants with a prevalence of ≥0.1%. Overall 201 PR, 636 RT, and 346 IN variants had a prevalence of ≥0.1%. The median intersubtype prevalence ratios were 2.9-, 2.1-, and 1.9-fold for these PR, RT, and IN variants, respectively. Only 5.0% of PR, 3.7% of RT, and 2.0% of IN variants had a median intersubtype prevalence ratio of ≥10-fold. Variants at lower prevalences were more likely to differ biochemically and to be part of an electrophoretic mixture compared to high-prevalence variants. There were 209 mutations indicative of APOBEC-mediated G-to-A editing and 326 mutations nonpolymorphic treatment selected. Identification of viruses with a high number of APOBEC-associated mutations will facilitate the quality control of dried blood spot sequencing. Identifying sequences with a high proportion of rare mutations will facilitate the quality control of NGS. IMPORTANCE Most antiretroviral drugs target three HIV-1 proteins: PR, RT, and IN. These proteins are highly variable: many different amino acids can be present at the same position in viruses from different individuals. Some of the amino acid variants cause drug resistance and occur mainly in individuals receiving antiretroviral drugs. Some variants result from a human cellular defense mechanism called APOBEC-mediated hypermutation. Many variants result from naturally occurring mutation. Some variants may represent technical artifacts. We studied PR and RT sequences from >100,000 individuals and IN sequences from >10,000 individuals to quantify variation at each amino acid position in these three HIV-1 proteins. We performed analyses to determine which amino acid variants resulted from antiretroviral drug selection pressure, APOBEC-mediated editing, and naturally occurring variation. Our results provide information essential to clinical, research, and public health laboratories performing genotypic resistance testing by sequencing HIV-1 PR, RT, and IN