Single-point Approach Research Articles

Ultrasound-guided Double-point Versus Single-point Serratus Anterior Plane Block for Modified Radical Mastectomy: A Randomized Controlled Trial.

The double-point serratus anterior plane block(SAPB) covers more area, including the axilla, than the single-point approach, potentially offering better pain relief after Modified radical mastectomy(MRM). Sixty women were randomly assigned to double or single-point groups. Double-point received SAPB at the third and fifth ribs, single-point at the fifth rib. Primary outcome: pain numeric rating scale (NRS) at rest and movement 24 hours post-surgery. Secondary outcomes: axilla comfort NRS, recovery quality, and adverse events. At 24 hours post-surgery, the double-point group compared to the single-point group showed movement pain NRS of 3 (2-3) vs. 3 (3-4) (P = 0.011) and rest pain NRS of 1 (1-1) vs. 2 (1-3) (P = 0.037). The difference between them did not exceed the MCID. The axillary comfort NRS in the double-point group was lower than the single-point group at 6 and 12 hours post-surgery, at 1 (1-2) vs. 2 (2-4) (P=0.001) and 1 (1-2) vs. 2 (2-4) (P=0.01) respectively, but there was no difference at 24 and 48 hours post-surgery. At 48 hours post-surgery, pain scores and opioid use were similar in both groups. Recovery scores, rescue analgesia timing, adverse events, and hospital stay length were similar in both groups. Double-point SAPB offers wider anesthetic spread but shows no significant clinical advantage in pain or axillary comfort over single-point SAPB after MRM.

Deep Learning for Detection and Localization of B-Lines in Lung Ultrasound.

Lung ultrasound (LUS) is an important imaging modality used by emergency physicians to assess pulmonary congestion at the patient bedside. B-line artifacts in LUS videos are key findings associated with pulmonary congestion. Not only can the interpretation of LUS be challenging for novice operators, but visual quantification of B-lines remains subject to observer variability. In this work, we investigate the strengths and weaknesses of multiple deep learning approaches for automated B-line detection and localization in LUS videos. We curate and publish, BEDLUS, a new ultrasound dataset comprising 1,419 videos from 113 patients with a total of 15,755 expert-annotated B-lines. Based on this dataset, we present a benchmark of established deep learning methods applied to the task of B-line detection. To pave the way for interpretable quantification of B-lines, we propose a novel "single-point" approach to B-line localization using only the point of origin. Our results show that (a) the area under the receiver operating characteristic curve ranges from 0.864 to 0.955 for the benchmarked detection methods, (b) within this range, the best performance is achieved by models that leverage multiple successive frames as input, and (c) the proposed single-point approach for B-line localization reaches an F 1-score of 0.65, performing on par with the inter-observer agreement. The dataset and developed methods can facilitate further biomedical research on automated interpretation of lung ultrasound with the potential to expand the clinical utility.

Single-point spin Chern number in a supercell framework

We present an approach for the calculation of the topological invariant in non-crystalline two-dimensional quantum spin Hall insulators. While topological invariants were originally mathematically introduced for crystalline periodic systems, and crucially hinge on tracking the evolution of occupied states through the Brillouin zone, the introduction of disorder or dynamical effects can break the translational symmetry and imply the use of larger simulation cells, where the k-point sampling is typically reduced to the single Γ-point. Here, we introduce a single-point formula for the spin Chern number that enables to adopt the supercell framework, where a single Hamiltonian diagonalisation is performed. Inspired by the work of Prodan (2009 Phys. Rev. B 80 125327), our single-point approach allows to calculate the spin Chern number even when the spin operator does not commute with the Hamiltonian, as in the presence of Rashba spin–orbit coupling. We validate our method on the Kane–Mele model, both pristine and in the presence of Anderson disorder. Finally, we investigate the disorder-driven transition from the trivial phase to the topological state known as topological Anderson insulator. Beyond disordered systems, our approach is particularly useful to investigate the role of defects, to study topological alloys and in the context of ab-initio molecular dynamics simulations at finite temperature.

Robotic single-site surgery versus laparoendoscopic single-site surgery in early-stage endometrial cancer: a case-control study.

IntroductionLaparoendoscopic single-site surgery (LESS) can reduce the limited invasiveness of conventional laparoscopy while providing superior cosmetic results. Robotic single-site surgery (RSSS) can overcome this shortcoming to a certain extent.AimTo evaluate the advantages of RSSS in treating early-stage endometrial cancer by comparing RSSS with LESS.Material and methodsFrom January 2018 to August 2018, patients diagnosed with endometrial cancer from endometrial curettage and imaging studies were selected for this prospective cohort study, with 22 undergoing RSSS and 18 undergoing LESS. All surgical procedures were performed using the conventional da Vinci Si surgical system with the Lagiport single port or a conventional laparoendoscopic instrument with the Lagiport single port. Operative time was recorded electronically. Intraoperative parameters and postoperative parameters were recorded and further analyzed.ResultsThe operation was successfully completed, and a pure single-point approach was adopted. There were no laparotomy or intraoperative complications. Compared with the LESS group, the RSSS group had significantly longer pre-surgical time, significantly lower median operation time, significantly lower median blood loss, and significantly lower vaginal cuff closure time. The median length of hospital stay in the RSSS group was significantly lower than that in the LESS group. There was no significant difference in the incidence of early and late complications between the two groups. No recurrence events were observed in either the RSSS or the LESS group.ConclusionsRSSS is feasible and safe in patients with early-stage endometrial cancer. RSSS can reduce operating time, blood loss and length of hospital stay compared with LESS.

Two-point Stokes vector diagnostic approach for characterization of optically anisotropic biological tissues

The purpose of the study is to demonstrate a new method of Stokes-correlometric evaluation of polarization-inhomogeneous images of optically thin (optical thickness smaller than 0.01) histological sections from optically anisotropic biological tissues of different morphological structure. This method is based on a correlation (‘two-point’) generalization of traditional optical methods for analyzing ‘one-point’ distributions of polarization states of microscopic images of biological tissues. Analytical algorithms are obtained for describing the ‘two-point’ complex parameters of the Stokes vector image of a birefringent biological tissue. An experimental technique has been developed for measuring polarization-correlation maps, i.e. the coordinate distributions of the magnitude and phase of the ‘two-point’ Stokes vector parameters. Within the framework of the statistical and correlation analysis of the obtained data, new quantitative criteria for the differentiation of the optical properties of biological tissues of various morphological structures are found. A comparative analysis of the distribution of the ‘single-point’ and ‘two-point’ parameters of the Stokes vector of polarizationally inhomogeneous images was performed. It revealed a higher sensitivity (2–5 times) of the Stokes-correlometry method to variations in orientation-phase structure of biological tissues compared to the single-point approach.

TUM-ParticleTyper: A detection and quantification tool for automated analysis of (Microplastic) particles and fibers.

TUM-ParticleTyper is a novel program for the automated detection, quantification and morphological characterization of fragments, including particles and fibers, in images from optical, fluorescence and electron microscopy (SEM). It can be used to automatically select targets for subsequent chemical analysis, e.g., Raman microscopy, or any other single particle identification method. The program was specifically developed and validated for the analysis of microplastic particles on gold coated polycarbonate filters. Our method development was supported by the design of a filter holder that minimizes filter roughness and facilitates enhanced focusing for better images and Raman measurements. The TUM-ParticleTyper software is tunable to the user’s specific sample demands and can extract the morphological characteristics of detected objects (coordinates, Feret’s diameter min / max, area and shape). Results are saved in csv-format and contours of detected objects are displayed as an overlay on the original image. Additionally, the program can stitch a set of images to create a full image out of several smaller ones. An additional useful feature is the inclusion of a statistical process to calculate the minimum number of particles that must be chemically identified to be representative of all particles localized on the substrate. The program performance was evaluated on genuine microplastic samples. The TUM-ParticleTyper software localizes particles using an adaptive threshold with results comparable to the “gold standard” method (manual localization by an expert) and surpasses the commonly used Otsu thresholding by doubling the rate of true positive localizations. This enables the analysis of a statistically significant number of particles on the filter selected by random sampling, measured via single point approach. This extreme reduction in measurement points was validated by comparison to chemical imaging, applying both procedures to the same area at comparable processing times. The single point approach was both faster and more accurate proving the applicability of the presented program.

Technical Note: Single time point dose estimate for exponential clearance.

Although personalized dosimetry may be desirable for radionuclide therapy treatments, the multiple time samples required to determine the total integrated activity puts a burden on patients and clinic resources. The aim of this paper is to demonstrate that when some prior knowledge is known about the tracer kinetic parameters, the total integrated activity (and thus radiation dose) can be estimated from a single time sample. Mathematical derivations have been performed to generate equations for the total integrated activity in terms of a single time sample of activity for monoexponential and biexponential clearance. Simulations were performed using both exponential models where the rate constants and associated parameters were randomly sampled from distributions with a known mean. The actual total integrated activity for each random sample was compared with the estimated total integrated activity using the mean value of the parameters. Retrospective analysis of 90 Y DOTATOC data from a clinical trial provided a comparison of actual kidney dose with the estimated kidney dose using the single time point approach. The optimal sampling time for the single point approach was found to be equal to the mean time of the rate constant. The simulation results for the monoexponential and biexpoential models were similar. Regressions comparing the actual and estimated total integrated activity had very high correlations (r2 >0.95) along with acceptable standard errors of estimate, especially at the optimal sampling point. The retrospective analysis of the 90 Y DOTATOC data also yielded similar results with an r2 =0.95 and a standard error of estimate of 61cGy. In situations where there is prior knowledge about the population averages of kinetic parameters, these results suggest that the single time point approach can be used to estimate the total integrated activity and dose with sufficient accuracy to manage radionuclide therapy. This will make personalized dosimetry much easier to perform and more available to the community.

Analysis of domestic refrigerator temperatures and home storage time distributions for shelf-life studies and food safety risk assessment

In the framework of food safety, when mimicking the consumer phase, the storage time and temperature used are mainly considered as single point estimates instead of probability distributions. This singlepoint approach does not take into account the variability within a population and could lead to an overestimation of the parameters. Therefore, the aim of this study was to analyse data on domestic refrigerator temperatures and storage times of chilled food in European countries in order to draw general rules which could be used either in shelf-life testing or risk assessment. In relation to domestic refrigerator temperatures, 15 studies provided pertinent data. Twelve studies presented normal distributions, according to the authors or from the data fitted into distributions. Analysis of temperature distributions revealed that the countries were separated into two groups: northern European countries and southern European countries. The overall variability of European domestic refrigerators is described by a normal distribution: N (7.0, 2.7)°C for southern countries, and, N (6.1, 2.8)°C for the northern countries. Concerning storage times, seven papers were pertinent. Analysis indicated that the storage time was likely to end in the first days or weeks (depending on the product use-by-date) after purchase. Data fitting showed the exponential distribution was the most appropriate distribution to describe the time that food spent at consumer's place. The storage time was described by an exponential distribution corresponding to the use-by date period divided by 4. In conclusion, knowing that collecting data is time and money consuming, in the absence of data, and at least for the European market and for refrigerated products, building a domestic refrigerator temperature distribution using a Normal law and a time-to-consumption distribution using an Exponential law would be appropriate.

Challenges in Determining Intrinsic Viscosity Under Low Ionic Strength Solution Conditions.

To determine the intrinsic viscosity of several monoclonal antibodies (mAbs) under varying pH and ionic strength solution conditions. An online viscosity detector attached to HPLC (Viscotek®) was used to determine the intrinsic viscosity of mAbs. The Ross and Minton equation was used for viscosity prediction at high protein concentrations. Bulk viscosity was determined by a Cambridge viscometer. At 15mM ionic strength, intrinsic viscosity of the mAbs determined by the single-point approach varied from 5.6 to 6.4mL/g with changes in pH. High ionic strength did not significantly alter intrinsic viscosity, while a significant increase (up to 24.0mL/g) was observed near zero mM. No difference in bulk viscosity of mAb3 was observed around pH 6 as a function of ionic strength. Data analysis revealed that near zero mM ionic strength limitations of the single-point technique result in erroneously high intrinsic viscosity. Intrinsic viscosity is a valuable tool that can be used to model baseline viscosity at higher protein concentrations. However, it is not predictive of solution non-ideality at higher protein concentrations. Furthermore, breakdown of numerous assumptions limits the applicability of experimental techniques near zero mM ionic strength conditions. For molecules and conditions studied, the single-point approach produced reliable intrinsic viscosity results at 15mM. However, this approach must be used with caution near zero mM ionic strength. Data analysis can be used to reveal whether determined intrinsic viscosity is reliable or erroneously high.

Single point approach for a successful and satisfactory patient care

Single point approach for a successful and satisfactory patient care

Time Truncated Testing Strategy using Multiple Testers: Lognormal Distributed Lifetime

In this study, group acceptance sampling plan proposed by Aslam et al. (2011) is reconsidered when the lifetime variant of the test item follows lognormal distribution. The optimal plan parameters are obtained by considering various pre-specified parameters. The plan parameters are obtained using the non-linear optimization solution using two points approach. The advantage of the proposed plan is discussed over the existing plan using the single point approach and the proposed plan is more efficient than the existing plan.

An adaptive single-point algorithm for global numerical optimization

This paper describes a novel algorithm for numerical optimization, called Simple Adaptive Climbing (SAC). SAC is a simple efficient single-point approach that does not require a careful fine-tunning of its two parameters. SAC algorithm shares many similarities with local optimization heuristics, such as random walk, gradient descent, and hill-climbing. SAC has a restarting mechanism, and a powerful adaptive mutation process that resembles the one used in Differential Evolution. The algorithms SAC is capable of performing global unconstrained optimization efficiently in high dimensional test functions. This paper shows results on 15 well-known unconstrained problems. Test results confirm that SAC is competitive against state-of-the-art approaches such as micro-Particle Swarm Optimization, CMA-ES or Simple Adaptive Differential Evolution.

Correlation analysis and imaging technique of TEM data

Although the transient electromagnetic method (TEM) has been used in geo-exploration for many years, the inversion precision of TEM data is still very limited and new techniques are needed to improve TEM data interpretation. Mathematically, TEM data can be converted into a series of virtual waves. Multi-aperture electromagnetic modelling shows that the coherence of multi-aperture TEM and echo waves measured at adjacent positions from the same geological body is high. Therefore, it is feasible to apply multi-aperture synthesis to TEM data. Based on the idea of synthetic aperture radar, a new data-processing method has been developed that uses superposition to realise multi-aperture data integration as well as Kirchhoff migration and imaging. After the pseudo-wavelet extraction from TEM data, the traditional approach of profile-based multi-aperture synthesis has been developed for each survey station. Furthermore, the traditional single point approach was applied for multiple point coverage. The technology of synthetic aperture improves TEM resolution, rendering it possible to extract information from TEM data that cannot be obtained by conventional methods. Experiments with both synthetic and survey data show that synthetic aperture imaging is effective, paving the way for developing a new TEM imaging technology.

Adjoint Aerodynamic Design Optimization for Blades in Multistage Turbomachines—Part II: Validation and Application

This is the second part of a two-part paper. First, the design-optimization system based on the adjoint gradient solution approach as described in Part I is introduced. Several test cases are studied for further validation and demonstration of the methodology and implementation. The base-line adjoint method as applied to realistic 3D configurations is demonstrated in the redesign of the NASA rotor 67 at a near-choke condition, leading to a 1.77% efficiency gain. The proposed adjoint mixing plane is applied to the redesign of a transonic compressor stage (DLR compressor stage) and an IGV-rotor-stator configuration of a Siemens industrial compressor at a single-operating point, both producing measurably positive efficiency gains. An examination on the choice of the operating mass flow condition as the basis for the performance optimization, however, highlights the limitation of the single-point approach for practical applications. For the three-row compressor configuration, a near peak-efficiency point based redesign leads to a measurable reduction in the choke mass flow, while a near-choke point based redesign leads to a significant performance drop in other flow conditions. Subsequently, a parallel multipoint approach is implemented. The results show that a two-point design optimization can produce a consistently better performance over a whole range of mass flow conditions compared with the original design. In the final case, the effectiveness of the present method and system is demonstrated by a redesign applied to a seven-row industrial compressor at the design point, leading to a remarkable 2.4% efficiency gain.

Mixed model approaches for the identification of QTLs within a maize hybrid breeding program.

Two outlines for mixed model based approaches to quantitative trait locus (QTL) mapping in existing maize hybrid selection programs are presented: a restricted maximum likelihood (REML) and a Bayesian Markov Chain Monte Carlo (MCMC) approach. The methods use the in-silico-mapping procedure developed by Parisseaux and Bernardo (2004) as a starting point. The original single-point approach is extended to a multi-point approach that facilitates interval mapping procedures. For computational and conceptual reasons, we partition the full set of relationships from founders to parents of hybrids into two types of relations by defining so-called intermediate founders. QTL effects are defined in terms of those intermediate founders. Marker based identity by descent relationships between intermediate founders define structuring matrices for the QTL effects that change along the genome. The dimension of the vector of QTL effects is reduced by the fact that there are fewer intermediate founders than parents. Furthermore, additional reduction in the number of QTL effects follows from the identification of founder groups by various algorithms. As a result, we obtain a powerful mixed model based statistical framework to identify QTLs in genetic backgrounds relevant to the elite germplasm of a commercial breeding program. The identification of such QTLs will provide the foundation for effective marker assisted and genome wide selection strategies. Analyses of an example data set show that QTLs are primarily identified in different heterotic groups and point to complementation of additive QTL effects as an important factor in hybrid performance.

Flow-Rate Estimation From Wellhead-Pressure and Temperature Data

Summary Flow-rate metering has a less-than-satisfactory track record in the industry. Modern sensors offer a solution to this vexing problem. This paper offers two methods for estimating flow rates, predominantly from temperature data to complement-rate measurements. One approach consists of modeling the entire wellbore and requires both wellhead pressure (WHP) and wellhead temperature (WHT), whereas the other uses transient temperature formulation at a single point in the wellbore to compute the total production rate. In the entire-wellbore approach, we use a wellbore model handling steady flow of fluids but unsteady-state heat transfer to estimate production rate, given wellhead pressure and temperature. The model rigorously accounts various thermal properties of the fluid and the formation, including Joule-Thompson (J-T) (Thompson and Joule 1853) heating and/or cooling. In the single-point approach, a single-point-temperature measurement made anywhere in the wellbore, including at the wellhead, is needed to estimate the mass rate at a given timestep. The method entails full transient treatment of the coupled fluid-and heat-flow problem at hand. Examples from both gas and oil wells are shown to illustrate the application of the proposed methodology. Good correspondence between the measured and calculated results demonstrates the robustness of the proposed methods. These methods provide important rate information in various settings. For instance, in mature assets they can fill in the information void between tests or replace suspect rate data. Even well-instrumented wells can benefit because the methods can act as a verification tool, particularly in assets where integrated asset models are used to fine tune rate allocation. In addition, the single-point approach can provide the much needed rate information during pressure-transient tests.

State-of-the-Art and Trends in Scalable Video Compression With Wavelet-Based Approaches

Scalable video coding (SVC) differs form traditional single point approaches mainly because it allows to encode in a unique bit stream several working points corresponding to different quality, picture size and frame rate. This work describes the current state-of-the-art in SVC, focusing on wavelet based motion-compensated approaches (WSVC). It reviews individual components that have been designed to address the problem over the years and how such components are typically combined to achieve meaningful WSVC architectures. Coding schemes which mainly differ from the space-time order in which the wavelet transforms operate are here compared, discussing strengths and weaknesses of the resulting implementations. An evaluation of the achievable coding performances is provided considering the reference architectures studied and developed by ISO/MPEG in its exploration on WSVC. The paper also attempts to draw a list of major differences between wavelet based solutions and the SVC standard jointly targeted by ITU and ISO/MPEG. A major emphasis is devoted to a promising WSVC solution, named STP-tool, which presents architectural similarities with respect to the SVC standard. The paper ends drawing some evolution trends for WSVC systems and giving insights on video coding applications which could benefit by a wavelet based approach.

A Novel Approach Based on Nonactive Power for the Identification of Disturbing Loads in Power Systems

In this paper, a new approach is proposed for the detection of harmonic sources in polluted power systems. It is a single- point strategy, based on a comparison among different "nonactive" power quantities proposed in literature that, in the same working conditions, assume different values at the same metering section. Some simulations tests were carried out on a standard IEEE test system proposed by other authors as a benchmark system for the analysis of multipoint measurement techniques for harmonic pollution monitoring. The obtained results show that the proposed single-point approach is in agreement with other strategies already proposed in the literature and can provide useful indications for the detection of the dominant harmonic source upstream or downstream the metering section also in some critical cases.

Offshore Absolute Calibration of Space-Borne Radar Altimeters

Absolute calibration of sea level measurements collected from space-borne radar altimeters is usually performed with respect to collocated sea level in situ records from tide gauges or GPS buoys (Ménard et al. 1994; Haines et al. 1996; Bonnefond et al. 2003; Haines et al. 2003; Schum et al. 2003; Watson et al. 2003; Watson et al. 2004). Such a method allows regular and long-term control of altimetric systems with independent records. However, this approach is based on a single, geographically dependent point. In order to obtain more significant and accurate bias and drift estimates, there is a strong interest in multiplying the number of calibration opportunities. This article describes a method, called the “offshore method” that was developed to extend the single-point approach to a wider regional scale. The principle is to compare altimeter and tide gauge sea level data not only at the point of closest approach of an overflying pass, but also at distant points along adjacent satellite passes. However, connecting sea level satellite measurements with more distant in situ data requires a more accurate determination of the geoid and mean ocean dynamic topography slopes, and also of the ocean dynamical changes. In this demonstration experiment, 10 years of averaged TOPEX/Poseidon mean sea level profiles are used to precisely determine the geoid and the mean ocean circulation slope. The Mog2d barotropic ocean model (Carerre et Lyard 2003) is used to improve our estimate of the ocean dynamics term. The method is first validated with Jason-1 data, off Corsica, where the dedicated calibration site of Senetosa provides independent reference data. The method is then applied to TOPEX/Poseidon on its new orbit and to Geosat Follow On. The results demonstrate that it is feasible to make altimeter calibrations a few tens to hundreds of kilometers away from a dedicated site, as long as accurate mean sea level altimeter profiles can be used to ensure the connection with reference tide gauges.

Minimizing Error in the Determination of P50

The measurement of P 50 in whole blood, defined as the oxygen tension corresponding to 50% oxygen saturation, gives a quantitative measure of hemoglobin oxygen affinity. The determination of P 50 is useful for screening for hemoglobin variants in cases of unexplained anemia or erythrocytosis, both because it is easily performed and because many hemoglobin variants with abnormal oxygen affinity are “silent”, i.e., not detectable with conventional electrophoretic techniques (1). The determination of P 50 previously required obtaining several points on the oxyhemoglobin dissociation curve. The procedure was seldom performed because of the labor and specialized apparatus required. However, it was suggested >25 years ago that P 50 could be accurately calculated from single measurements of oxygen tension ( P o2) and the corresponding oxygen saturation ( S o2) (2). Since then, an improved mathematical model of the oxyhemoglobin dissociation curve (3) has been incorporated into a guideline for the so-called “single-point” determination of P 50 (4) that has been tested (5)(6) and subsequently approved by the IFCC. The single-point approach is based on the fact that a plot of log P o2 vs log[ S o2/(1 − S o2)], the so-called Hill plot, is linear over a fairly wide interval. Therefore, if one knows both the slope and one point on the line, any other point on the line can be determined. There have been different recommendations for the interval within which the single-point method is valid. Some studies have suggested that it can be used for oxygen saturations as low as 20% (5). The original IFCC guideline (4) specified saturations in the interval between 40% and 80%, and a subsequent IFCC document on definitions of quantities used in blood pH and gas analysis (7) extended the upper limit to 90% saturation. …