Plane Parallel Research Articles

Analysis of the left atrial appendage function by intracardiac echocardiography in patients with atrial fibrillation

Abstract Introduction Intracardiac echocardiography (ICE) is frequently performed during catheter ablation procedures in order to guide the transseptal puncture and has been recently used to evaluate the morphology of the LAA. Purpose The objective of this study was to evaluate the feasibility of using an ICE catheter placed in the coronary sinus (CS) to delineate the LAA function during catheter ablation for atrial fibrillation. Methods We included 21 consecutive patients (age 62±9 years, 5 women, 6 paroxysmal AF) who underwent catheter ablation for AF. An 8-Fr phased-array ICE catheter was used to obtain images of the LAA, while in sinus rhythm. The LAA was visualized with the ICE probe placed sequentially in the left atrium (LA, Figure A), with the ultrasound section plane parallel to the long axis of the left ventricle (LV), and in the CS, with the ultrasound section plane perpendicular to the LV long axis (Figure B). LAA emptying flow velocity, and LAA fractional area change (FAC) were used to evaluate LAA function. There were no procedural complications. Results ICE imaging was possible in all cases. The LAA peak flow velocity was similar when the ICE catheter was placed in the LA and in the CS (64±7 cm/s and 62±5cm/s respectively, P=NS). The LAA FAC was significantly lower when the ICE catheter was placed in the CS when compared to an LA location (14±6% vs 36±14%; P<0.001). The LAA FAC measured from the LA correlated with the mitral annular plane systolic excursion while the LAA FAC measured from the CS did not. Thus, LAA contraction in a plane perpendicular to the LV long axis is independent of the LV longitudinal contraction. These results suggest that in our patient group most of the LAA contraction was due to the longitudinal movement of the LV base during systole and diastole. Conclusions Imaging of LAA using an ICE probe positioned in the LA and CS was feasible in all cases. The LV longitudinal contraction appears to impact the LAA function.

Mechanical Microdeformation and Kink–band Formation in Mica from the Colônia Impact Crater, São Paulo, Brazil

A comprehensive examination using a transmitted light optical microscope was conducted to analyze the morphology and geometric parameters of kink band development in mica from the Colônia impact crater's crystalline basement rocks. Significant differences were observed between kink bands formed perpendicular and parallel to the [001] plane. Kink bands perpendicular to the [001] are narrow and elongated, exhibiting two distinct coplanar orientations with regular spacing and parallel planar fractures, which suggest a slip-dislocation strain mechanism. In contrast, kink bands parallel to the [001] plane exhibit a greater variety of shapes and a more complex internal structure. These kink bands can be grouped into six types: sigmoidal-shape, S-shape, lenticular-shape, Z-shape, Z-shape with internal dislocation, and Z-shape with internal rotation. The deformation patterns in these kink bands indicate two primary processes: flexural and shear strain. The most notable deformations induced by these strain mechanisms include the curvature of cleavage lamellae, delamination cracks, and fractures along the boundaries of kink bands. More severely deformed kink bands exhibit dislocation, rotation, and partial obliteration of internal cleavage lamellae. These characteristics differ from those of typical kink bands in tectonically deformed rocks, thereby reviving the longstanding debate regarding their potential use as alternative evidence in impact cratering investigations.

Anomalous heat transfer enhancement in separated flow over a zigzag-shaped dense package of inclined grooves in a channel wall at different temperature boundary conditions

Rapid development of the anomalous enhancement of separated turbulent Re = 6000 air flow and heat transfer in an in-line single-row package of 31 inclined grooves, 0.2 in dimensionless depth, in a singled-out longitudinal region of the wall of a narrow channel is studied. It is due to the interference of vortex wakes behind the grooves and the acceleration in the channel flow core with the formation of a zone of ultrahigh longitudinal velocity. The wave-shaped parameter characteristics are stabilized in the region of approximately 15th groove, whereupon the oscillation amplitudes are moderately reduced. The return flows in the grooves are enhanced with distance from the entry section, the minimum negative friction diminishing from −2 to −4. The total relative heat removal from the structured region increases atq= const by a factor of approximately 2.75 and by the factor of two atT= const with increase in the relative hydraulic losses by the factor of 1.7, as compared with the case of a plane–parallel channel. The relative heat removal from the surface bounded by the contour of the 20th inclined groove amounts to 3.7 (q= const) with increase in the hydraulic losses by the factor of 2.2. An increase in the local maximum of the longitudinal velocity up to a factor of 1.5, as compared with the mean-mass velocity, can be observable.

Versatile Metamaterial: Exploring the Resonances of Symmetry‐Protected Modes for Multitasking Functionality

AbstractIn this work, an experimental study supported by numerical modeling that demonstrates the possibility of exciting Symmetry Protected‐Bound states In the Continuum (SP‐BICs) in a 1D silicon grating fabricated on a lithium niobate substrate is presented. bBoth transverse electric and magnetic polarization states are investigated, leading to the excitation of four quasi‐ Bound states In the Continuum (quasi‐BIC) resonances, exhibiting distinct behaviors. Under standard illumination conditions (plane of incidence perpendicular to the 1D grating lines), two of these resonances are highly sensitive to illumination conditions, while the other two resonances involving unconventional illumination directions (plane of incidence parallel to the grating lines) are more robust to the angle of incidence, but just as sensitive to external stresses in terms of resonance wavelength and quality factor. Additionally, temperature detection is experimentally demonstrated with a Sensitivity of ST = 0.81∼nm °C−1, a state‐of‐the‐art value achieved due to significant electromagnetic field enhancement inside the lithium niobate substrate at the quasi‐BIC resonance. These findings pave the way for their use in various sensing applications (such as biology, electromagnetic, and temperature sensing), as well as nonlinear applications like second harmonic generation, and electro‐ and acousto‐optic modulation.

Macroscopic and microscopic investigations of determining elasto-mechanical properties of limequat fruit.

Given the paramount importance of agricultural products in global health and food security, and the increasing consumer demand, understanding the mechanical behavior of these materials under various conditions is necessary yet challenging. Due to their heterogeneous and non-uniform nature, determining their mechanical behavior is complex. This study employs atomic force microscopy (AFM) to determine the modulus of elasticity of limequat fruit at the microscopic scale and compares it with macroscopic methods. The analyses revealed a statistically significant difference (at the 1% level) in the mechanical behavior determined at the macroscopic scale. The highest modulus of elasticity, 0.752 MPa, was observed using Hertz's theory under complete placement between two parallel planes. The lowest, 0.059 MPa, was noted when a spherical probe compressed a rectangular sample. The average modulus of elasticity of the limequat peel was 2.007 MPa. At the microscopic scale, the modulus of elasticity of the fruit tissue ranged from 0.370 to 0.365 MPa, and for the peel, it was 0.246 MPa. RESEARCH HIGHLIGHTS: Working principles of this innovative technique were elaborated. The AFM technique used provide elasto-mechanical properties determination of cell walls of single living cells extracted from biological materials on the nanoscale. By combining AFM topographical image and nano-indentation of living fruit cells it will be possible to investigate cells' elasto-mechanical properties. Atomic force microscopy holds great potential for monitoring fruit mechanical properties of biological materials.

Estimation and experiment on acoustic properties of rice straw (estimation of sound absorption coefficient based on CT image)

The sound absorption characteristics of rice straw were estimated using micro-CT scan images and theoretical analysis. Since it is difficult to express the structure and dimensions of rice straw in a regular manner, the voids in the straw were approximated as clearance between two parallel planes based on the micro-CT scan images. Using the surface area of the straw and the volume of the voids, a theoretical estimation of the sound absorption coefficient of the straw was made. Propagation constants, characteristic impedance, and normal incident sound absorption coefficient were obtained for the derived clearance. Since the rice straw is tubular, the sound absorption coefficient was also obtained assuming that an arbitrary CT scan image is continuous in the thickness direction. In addition, the sound absorption coefficient was estimated from ordinary photographs taken of the sample incident surface. In the experiments, the sound absorption coefficient was measured using a two-microphone impedance tube. The theoretical values were close to the experimental value.

3D evaluation of sagittal inclination of the maxillary dentition in relation to facial landmarks: A cohort study.

The determination of the maxillary occlusal plane presents a significant clinical challenge in the treatment of edentulous patients as well as it is critical for complex full-mouth reconstructions in dentate patients, including those with implant-supported rehabilitations. While the use of a Fox plane plate is standard in edentulous cases, its application in dentate patients lacks thorough documentation in existing literature. This clinical study assessed the sagittal position of the maxillary dentition in relation to facial landmarks using a digital three-dimensional analysis and evaluated the suitability and reliability of applying a simulated Fox plane plate, also known as an occlusal plane guide, in dentate patients. Eighty-one subjects were recruited at the Department of Prosthetic Dentistry of Goethe University Frankfurt, Germany, according to specific inclusion criteria. Intraoral and facial scans were obtained and analyzed using GOM Inspect Pro software (GOM, Braunschweig, Germany). The angles between the maxillary occlusal plane and three variations each of Camper's plane and ala-tragus line, relating to superior, middle, and inferior tragus points, were measured. These modified planes were then compared to a plane established by a simulated digital Fox plane plate, which was adapted to the maxillary anterior teeth and the lowest point of the posterior teeth in both quadrants. A total of 81 subjects (58 female and 23 male) with a mean age of 23.9 years were evaluated in this study. No significant angular difference was found between the angles of the maxillary occlusal plane compared with superior Camper's plane, middle Camper's plane, or superior ala-tragus line (p >0.05). The smallest angle occurred between superior Camper's plane and the maxillary occlusal plane on both the right (3.443°) and left (3.535°) sides. The application of a Fox plane plate resulted in two different occlusal planes in 70% of patients, significantly deviating from the digitally determined plane (p <0.05). Superior and middle Camper's planes, along with superior ala-tragus line, can be considered approximately parallel reference planes and are suitable for routine determining of the maxillary occlusal plane in restorative treatments. However, in contrast to digital evaluation methods, the application of a Fox plane plate in dentate patients showed high variability, indicating its low reproducibility due to its ambiguous positioning on the maxillary dentition. Clinical trial registration site: https://drks.de/search/de/trial/DRKS00030166.

Single-channel high-precision laser rangefinder

The article deals with the construction of a single-channel light rangefinder. At the same time, one of the main difficulties is the presence of depolarization of light, which forms residual light at the output of the analyzer, which greatly affects the measurement accuracy. It is shown that in order to exclude residual light by compensating for depolarization, a KDP crystal plate with the possibility of rotation in a plane parallel to the optical axis is installed at the input of the demodulator.The possibility of using an optical delay line on a single mirror with the possibility of moving along the axis of the radiation source is also considered. The normal to the mirror surface and the optical axes of the KDP crystals are located to the axis of the light source at an angle of 0.7–0.9∘.

Evaluating the Transmission Type Reference Chamber for Small Field Dosimetry

AbstractTo assess the efficacy of a transmission‐type parallel plane reference chamber (T‐REF) for small‐field percentage depth dose (PDD) measurements using two high‐resolution detectors. The study utilizes microSilicon and microDiamond detectors for small‐field measurements, both with and without a T‐REF reference chamber. TrueBeam linear accelerator provides various photon energies (6X, 6XFFF, 10X, 10XFFF) for depth dose measurements. A sun‐nuclear 3D water tank is used to measure the PDD up to a depth of 15 cm. Analysis of the data includes a 1D gamma passing rate calculated using an in‐house MATLAB program. The study compares the PDD measurements obtained with and without the T‐REF. The T‐REF exhibits negligible beam perturbations across different field sizes and energies. The overall maximum mean PDD differences are 0.31 ± 0.16% for microSilicon and 0.33 ± 0.17% for microdiamond. The overall mean 1D gamma passing rate is 99.6 ± 0.2%. This study demonstrates that the T‐REF is a reliable and effective reference detector for small‐field radiation dosimetry.

Modeling the Effect of Cell Orientation on the Performance of an Air-Breathing Polymer Electrolyte Fuel Cell with a Columnar Cathode Plate

Air-breathing polymer electrolyte fuel cells (PEMFCs) are expected to play an important role in the development of sustainable portable and mobile devices, such as unnamed aerial vehicles, motorbikes or laptops. In this work, the performance of air-breathing PEMFCs with a columnar cathode plate design is examined by means of a 3D two-phase, non-isothermal model, and compared against experimental data. The results show that the performance is highly influenced by the cell orientation, namely horizontal (material plane perpendicular to gravity) versus vertical (material plane parallel to gravity). Oxygen transport in horizontal cells is mainly dominated by diffusion, leading to oxygen shortage toward the cell center and an inhomogeneous current density distribution. In contrast, oxygen transport in vertical cells is assisted by natural convection, enhancing oxygen transport throughout the cell and increasing the current density homogeneity. Water saturation is preferentially accumulated close to the cell center, being larger in horizontal cells due to the lower water removal rate of the cathode plate.

Modeling the Effect of Cell Orientation on the Performance of an Air-Breathing Polymer Electrolyte Fuel Cell with a Columnar Cathode Plate

Air-breathing polymer electrolyte fuel cells (PEMFCs) are expected to play an important role in the development of sustainable portable and mobile devices, such as unnamed aerial vehicles, motorbikes or laptops. In this work, the performance of air-breathing PEMFCs with a columnar cathode plate design is examined by means of a 3D two-phase, non-isothermal model, and compared against experimental data. The results show that the performance is highly influenced by the cell orientation, namely horizontal (material plane perpendicular to gravity) versus vertical (material plane parallel to gravity). Oxygen transport in horizontal cells is mainly dominated by diffusion, leading to oxygen shortage toward the cell center and an inhomogeneous current density distribution. In contrast, oxygen transport in vertical cells is assisted by natural convection, enhancing oxygen transport throughout the cell and increasing the current density homogeneity. Water saturation is preferentially accumulated close to the cell center, being larger in horizontal cells due to the lower water removal rate of the cathode plate.

The deformation mechanism of low symmetric Ti–Pt intermetallic compounds containing high density of planar defects

Intermetallic compounds typically exhibit limited plastic deformation capacity due to challenges in activating dislocation slip and deformation twinning, coupled with a lack of alternative deformation mechanisms. Ti–Pt alloys are a prevalent type of intermetallic compound utilized in high-temperature shape memory alloys and as materials for energy applications in electric fields. However, they often exhibit poor deformation capability. Here, we prepared a low-symmetry intermetallic phase, Ti4Pt3, which demonstrates significant plastic deformation capability. This phase features a high density of parallel planar defects, resulting in an exceptionally large lattice periodicity perpendicular to these defects. Through in-situ scanning electron microscope compression tests, we observed substantial plastic deformation in this new phase. Analysis of the deformed Ti4Pt3 phase revealed that the dense planar defects create uniformly distributed sites of internal stress concentration, enabling a rapid increase in back stress within crystals. This phenomenon leads to notable lattice rotation and localized order-disorder transitions, both crucial mechanisms facilitating plastic deformation and enhancing deformation capacity. Our research underscores the potential of leveraging structural asymmetry to enable unconventional deformation mechanisms, thereby enhancing the plasticity of intermetallic materials.

Comparison of the mandibular retromolar space in adults with different sagittal skeletal types and eruption patterns of the mandibular third-molar: a cone-beam computed tomography study

BackgroundThe mandibular retromolar space (RMS) has not been extensively studied in relation to various sagittal skeletal classes and patterns of third-molar eruption. The objective of this study was to test the null hypothesis that there is no difference in the mandibular RMS among normodivergent subjects with different skeletal classes and patterns of mandibular third-molar eruption, using cone-beam computed tomography (CBCT).MethodA total of 105 normodivergent patients (20–40 years) were included in this study. Participants were categorized into Class I, II and III groups based on ANB and further impacted and erupted groups based on the eruption patterns of the mandibular third molars. Measurements of the mandibular RMS were taken at four planes parallel to the occlusal plane, along the cusp line. Comparative analyses were conducted among the three sagittal groups and between the impacted and erupted groups.ResultsThe Class II group exhibited a statistically smaller RMS (P < 0.05). RMS was found to be larger in third-molar erupted group (P < 0.05). The rates of root contact and third-molar impaction was significantly higher in Class II group. (P < 0.05)ConclusionsThe null hypothesis was rejected. Patients with Skeletal Class II tend to have a smaller mandibular RMS and a higher prevalence of root contact and third-molar impaction. The presence of impacted mandibular third molars was correlated with a shorter RMS.Trial registrationRetrospectively registered.

Structural and electronic transformations in TiO2 induced by electric current

In-situ diffuse neutron scattering experiments revealed that when electric current is passed through single crystals of rutile TiO2 under conditions conducive to flash sintering, it induces the formation of parallel planes of oxygen vacancies. Specifically, a current perpendicular to the c-axis generates planes normal to the (132) reciprocal lattice vector, whereas currents aligned with the c-axis form planes normal to the (132) and to the (225) vector. The concentration of defects increases with incresing current. The structural modifications are linked to the appearance of signatures of interacting Ti3+ moments in magnetic susceptibility, signifying a structural collapse around the vacancy planes. Electrical conductivity measurements of the modified material reveal several electronic transitions between semiconducting states (via a metal-like intermediate state) with the smallest gap being 27 meV. Pristine TiO2 can be restored by heating followed by slow cooling in air. Our work suggests a novel paradigm for achieving switching of electrical conductivity related to the flash phenomenon.

Pupil to limbus diameter ratio as an emerging autonomic function test and its correlation with anthropometric parameters in different phases of menstrual cycle

The menstrual cycle is a physiological change in normal females, indicating the proper functioning of both endocrine and reproductive health. The pupil to limbus diameter (PLD) ratio is defined as the ratio of pupil diameter measured at an axial plane to the limbus diameter measured at the same or a parallel axial plane. Alterations in estrogen and progesterone levels may influence cardiac autonomic functions. This study aimed to correlate the PLD ratio with anthropometric parameters, such as body mass index (BMI) and waist circumference (WC), during different phases of the menstrual cycle among medical students.Methods: A cross-sectional study was conducted among first- and second-year female MBBS students aged 17 to 22 years. Anthropometric parameters, including height, weight, BMI, and WC, were measured for all participants. Eye photographs were taken during the follicular and luteal phases of the menstrual cycle, and the diameters were measured manually using the two-box method. The PLD ratios for both eyes showed a significant positive correlation with BMI (right eye: r = 0.682, p &lt; 0.000; left eye: r = 0.430, p &lt; 0.000) and waist circumference (right eye: r = 0.456, p &lt; 0.000; left eye: r = 0.315, p &lt; 0.001). The PLD ratio can serve as a simple, non-invasive, and cost-effective autonomic function test.

Influence of contact angle hysteresis on forced oscillations of a clamped drop

We consider forced oscillations of a clamped liquid drop. The drop is surrounded by an incompressible fluid of a different density. In equilibrium, the drop has the form of a circular cylinder bounded axially by parallel solid planes, and the contact angle measures 90°. The specific boundary conditions are applied as follows: the contact line starts to slide only when the deviation of the contact angle exceeds a certain critical value. As a result, the stick-slip dynamics can be observed.

IMAGE-BASED YOLOV4 ARCHITECTURE FOR DETECTING MINERAL IN SEDIMENTARY ROCKS THIN SECTION

Thin section analysis of sedimentary rocks is the basis for identifying minerals and textures. In general, quantitative analysis of thin sections of rock often requires many hours of work when done manually. In today's era, mineralogical interpretation and percentage calculations must be carried out automatically using more practical applications. The research method begins with the identification of 44 thin section samples in parallel plane polarized (PPL) and crossed polarized (XPL) conditions with thin section analysis then mineralogy detection is carried out using a computational approach, namely the use of image-based Deep Learning YoloV4 architecture with 2D RGB image objects from the thin section of sedimentary rock. The results of this study show the best values of Average Precision in Quartz, Feldspar, and lithic are 39.21% in the XPL model, 26.53% in the XPL model, and 15.75% in combined mode, according to the training and testing of YoloV4 Models for the identification of rock minerals in thin sections. Based on the complexity of the mineral types, the granularity of the detection, and the specific geological objectives, establishing a meaningful benchmark or baseline for comparison is always challenging. Additionally, consider discussing the trade-offs between precision and recall, as a higher precision may be more critical in some geological applications. It is expected that the application of this research can produce practical, fast and accurate interpretation of the determination of minerals in sedimentary rocks from all thin-section images of rocks and thus provide a complete understanding of geological views automatically.

Kinematic analysis of multiple Compton scattering in quantum-entangled two-photon systems

The Stokes–Mueller method is used to analyze the scattering of entangled photon pairs in a two-photon system. This study examines the scenario where one of the photons, part of a pair of maximally entangled annihilation photons, undergoes intermediate Compton scattering before both photons are detected using Compton polarimeters. The method also accounts for potential quantum-decoherence effects resulting from Compton scattering. The analysis investigates the scattering behavior in both parallel and perpendicular planes, identifying variations in the modulation factor that affect azimuthal correlations. These variations include increases, decreases, sign changes, or disappearances at certain intermediate scattering angles. This work aims to provide theoretical results that support the testing and verification of predictions made by quantum field theory.

Simultaneous Necking and Barreling Deformation Behaviors in Bending of Single-Crystal Gold Micro-Cantilever.

Necking and barreling deformation behaviors occurred simultaneously during the bending test of a single-crystal gold micro-cantilever (sample A) with the loading direction parallel to the [1-10] orientation and the neutral plane parallel to the [110] orientation. In contrast, for another single-crystal gold micro-cantilever, sample B, with the loading direction aligned parallel to the [0.37 -0.92 0.05] orientation and the neutral plane parallel to the [0.54 0.28 0.78] orientation, predominant slip band deformation was noted. Sample A exhibited activation of four slip systems, whereas sample B demonstrated activity in only a single-slip system. This difference suggests that the presence of multiple slip systems contributes to the concurrent occurrence of necking and barreling deformations. Furthermore, variations in the thickness of the micro-cantilevers resulted in observable strengthening, indicating that the effect of sample size is intricately linked to the geometry of the cross-section, which we have termed the "sample geometry effect".

Study on the motion characteristics of continuously generated bubbles and power generation performance in the power generation channel of the liquid metal magneto-hydro-dynamics system

The motion characteristics of continuously generated bubbles and their influence on the power generation performance of the liquid metal magneto-hydro-dynamics system are numerically investigated under different surface tension coefficients and load coefficients based on the volume of fluid model. The results show that bubbles split and coalesce more frequently in the presence of a magnetic field, resulting in an oscillatory velocity distribution along the flow direction. Due to the wake effect, bubble splitting causes an uneven distribution of current density throughout the channel, reducing the stability of power generation. As surface tension inhibits bubble deformation, increasing the surface tension coefficient of the fluid reduces fluctuations in peak velocity and current density in the channel, thus enhancing the stability of power generation, but to some extent, it reduces the overall power generation. The shape of the bubbles shows anisotropy: in the plane perpendicular to the magnetic field, the bubbles are cap-shaped, whereas in the plane parallel to the electrode wall, the bubbles elongate in the direction parallel to the magnetic field as the load coefficient decreases, transitioning from elliptical to cap-shaped. Additionally, there exists an optimal load coefficient that maximizes the output power.