Orthogonal Configuration Research Articles

Biomechanical comparison of three internal fixation configurations for low transcondylar fractures of the distal humerus

BackgroundWe aimed to evaluate the biomechanical stiffness and strength of different internal fixation configurations and find suitable treatment strategies for low transcondylar fractures of the distal humerus. Methods and materialsThirty 4th generation composite humeri were used to create low transcondylar fracture models that were fixed by orthogonal and parallel double plates as well as posterolateral plate and medial screw (PPMS) configurations (n=10 in each group) using an anatomical locking compression plate-screw system and fully threaded medial cortical screws. Posterior bending (maximum 50 N), axial loading (maximum 200 N) and internal rotation (maximum 10 N·m) were tested, in that order, for each specimen. Stiffness under different biomechanical settings among different configurations were compared. Another 18 sets of fracture models were created using these three configurations (n=6 in each group) and the load to failure under axial loading among different configurations was compared. ResultsUnder posterior bending, the stiffness of parallel group was higher than orthogonal group (P<0.001), and orthogonal group was higher than PPMS group (P<0.001). Under axial loading, the stiffness of parallel group was higher than orthogonal group (P=0.001) and PPMS group (P<0.001); however, the difference between orthogonal and PPMS group was not statistically significant (P>0.05). Under internal rotation, the stiffness of parallel group was higher than orthogonal group (P=0.044), and orthogonal group was higher than PPMS group (P=0.029). In failure test under axial loading, the load to failure in the orthogonal group was lower than parallel group (P=0.009) and PPMS group (P=0.021), but the difference between parallel group and PPMS group was not statistically significant (P>0.05). All specimens in orthogonal group demonstrated “distal medial failure”; most specimens had “distal medial and trochlear failure” in the parallel group; most specimens exhibited “contact failure” in the PPMS group. ConclusionFor treating low transcondylar fractures, the overall stiffness and strength of the parallel configuration were superior to those of the orthogonal and PPMS configurations. Nevertheless, the PPMS configuration can provide adequate stability and stiffness comparable to double-plate configurations under axial loading. Therefore, the PPMS construct may have certain clinical value.

Low voltage area as a predictor of recurrence after a single pulmonary vein isolation procedure: results of the WAVE-MAP AF study

Abstract Background/Introduction Pulmonary vein isolation (PVI) is a recommended approach for atrial fibrillation (AF) ablation procedures. Substrate modification beyond PVI has mixed results but identifying and ablating low voltage zones and ablating those targets in addition to PVI may be beneficial. Electroanatomic mapping is critical to identify subjects that may require further substrate modification. Low voltage area may be predictive of optimal treatment approach. Purpose This was a prospective, multicenter, interventional study of a high-density grid-style mapping catheter (HD Grid) to characterize left atrial low voltage substrate during sinus rhythm (SR) and AF and identify associations with 12 month recurrence rates after a single de novo radiofrequency (RF) ablation using a PVI only approach. Methods This study (NCT03882021) enrolled 300 subjects at 18 centers in Europe and Israel. Subjects underwent de novo RF ablation for paroxysmal AF (PAF) (N=113), early persistent AF (PsAF; AF sustained 7 days to 3 months) (N=86) or non-early PsAF (AF sustained &amp;gt;3 months to 12 months) (N=101). High density voltage maps were collected with HD Grid. Two pre-ablation maps, in SR and AF, were created for each subject (N=196) followed by PVI only ablation. Low voltage area (using cutoffs of 0.1 mV to 1.5 mV) was investigated in SR and AF. Follow up visits were at 3, 6 and 12 months post-ablation, with a 24-hour Holter monitor at 12 months. A Cox proportional hazards model was used to identify associations between mapping data and 12 month AF/atrial flutter (AFL)/atrial tachycardia (AT) recurrence after a single PVI procedure. Results At 12 months, 75.5% of subjects were free from AF/AFL/AT recurrence. On average, PsAF subjects had more low voltage area than PAF subjects in SR and AF. However, while univariate analysis found no correlation between recurrence and PAF or PsAF diagnosis (p=0.1261), those with recurrence had a significantly larger percent left atrial low voltage area under 0.5 mV with simultaneous orthogonal bipole wave configuration (HDW) in both AF (p=0.0011) and SR (p=0.0210) than those without recurrence. Using HDW, low voltage area (identified as &amp;lt;0.5 mV) greater than 28% of the left atrium in SR (HR: 4.82, 95% CI: 2.08–11.18, p=0.0003) and greater than 72% in AF (HR: 5.66, 95% CI: 2.34–13.69, p=0.0001) were associated with a higher risk of AF/AFL/AT recurrence at one year. Conclusion(s) Using a standard cutoff of 0.5 mV, a larger percent low voltage area was associated with increased risk of recurrence in both SR and AF. Future analyses will explore optimal low voltage cutoffs and thresholds predictive of recurrence that may necessitate additional substrate modification beyond PVI. Funding Acknowledgement Type of funding sources: Private company. Main funding source(s): Abbott

An Aperture-Coupled Stepped Dielectric Resonator UWB MIMO Antenna With AMC

In this letter, an aperture-coupled stepped dielectric resonator (DR) ultrawideband (UWB) multiple-input–multiple-output (MIMO) antenna (UMA) is presented. The proposed stepped DR resonates with quasi TE <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sup> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">δ11</sub> at 5.4 GHz and quasi TE <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">y</sup> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1δ1</sub> mode at 6.4 GHz and merges with aperture resonating bands to achieve UWB. In the proposed orthogonal MIMO configuration, the stepped DR is able to improve the isolation in the higher frequency region and a modified neutralization line via a quarter wavelength square patch improves the isolation in the desired lower frequency region. The broadside radiating modes of the stepped DR and the dual artificial magnetic conductor (AMC) and PEC bands of the AMC reflector improves the gain and radiation characteristics. An improvement of 37.84% in gain stability within 2.3 dB variation (i.e., 4.2–6.5 dB) is achieved. The group delay of the UMA is more stable than the UWB antenna (UA). Thus, the problem of phase linearity is managed by multipath of the proposed UMA.

Intermediate and Power-law Inflation in the Tachyon Model with Constant Sound Speed

By adopting the intermediate and power-law scale factors, we study the tachyon inflation with constant sound speed. We perform some numerical analysis on the perturbation and non-Gaussianity parameters in this model and compare the results with observational data. By using the constraints on the scalar spectral index and tensor-to-scalar ratio obtained from Planck2018 TT, TE, and EE+lowE+lensing+BAO+BK14 data; the constraints on the running of the scalar spectral index obtained from Planck2018 TT, TE, and EE+lowEB+lensing data; and the constraints on tensor spectral index obtained from Planck2018 TT, TE, and EE+lowE+lensing+BK14+BAO+LIGO and Virgo2016 data, we find the observationally viable ranges of the model’s parameters at both 68% CL and 95% CL. We also analyze the non-Gaussian features of the model in the equilateral and orthogonal configurations. Based on Planck2018 TTT, EEE, TTE, and EET data, we find constraints on the sound speed of 0.276 ≤ c s ≤ 1 at 68% CL, 0.213 ≤ c s ≤ 1 at 95% CL, and 0.186 ≤ c s ≤ 1 at 97% CL.

The Orientation Selectivity of Dichoptic Masking Suppression is Contrast Dependent in Amblyopia.

PurposeWe aimed to study the effect of stimulus contrast on the orientation selectivity of interocular interaction in amblyopia using a dichoptic masking paradigm.MethodsEight adults with anisometropic or mixed amblyopia and 10 control adults participated in our study. The contrast threshold in discriminating a target Gabor in the tested eye was measured with mean luminance in the untested eye, as well as with a bandpass oriented filtered noise in the other eye at low spatial frequency (0.25 c/d). Threshold elevation, which represents interocular suppression, was assessed using a the dichoptic masking paradigm (i.e. the contrast threshold difference between the target only and masked conditions), for each eye. Orientation selectivity of the interocular suppression as reflected by dichoptic masking was quantified by the difference between the parallel and orthogonal masking configurations. Two levels of mask's contrast (3 times or 10 times that of an individual's contrast threshold) were tested in this study.ResultsThe strength of dichoptic masking suppression was stronger at high, rather than low mask contrast in both amblyopic and control subjects. Normal controls showed orientation-dependent dichoptic masking suppression both under high and low contrast levels. However, amblyopes showed orientation-tuned dichoptic masking suppression only under the high contrast level, but untuned under the low contrast level.ConclusionsWe demonstrate that interocular suppression assessed by dichoptic masking is contrast-dependent in amblyopia, being orientation-tuned only at high suprathreshold contrast levels of the mask.

High density wave mapping to characterize low voltage substrate in sinus rhythm and atrial fibrillation: acute results from the WAVE-MAP AF study

Abstract Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): Abbott Background Pulmonary vein isolation (PVI) is a recommended approach for all atrial fibrillation (AF) ablation procedures, but PVI alone does not cure all AF. Supplementary substrate modification beyond PVI has mixed results. Identifying low voltage zones and ablating those targets in addition to PVI may be beneficial. Electroanatomic mapping is critical to identify subjects that may require further substrate modification. The amount of low voltage area may be predictive of the optimal treatment approach. Purpose This was a prospective, multicenter, interventional study of a high-density grid-style mapping catheter (HD Grid) to characterize left atrial (LA) low voltage substrate during sinus rhythm (SR) and AF in subjects undergoing de novo radiofrequency (RF) ablation for paroxysmal AF (PAF), early persistent AF (PsAF) (7 days-3 months) or non-early PsAF (&amp;gt;3 months-12 months) using a PVI only approach. Methods High-density voltage maps were collected with HD Grid during both SR and AF prior to ablation. Differences in low voltage area between (1) SR and AF and (2) simultaneous orthogonal bipole wave configuration (HDW) and standard along-the-spline linear electrode configuration (SD) were investigated. Results Three hundred subjects, enrolled at 18 centers in Europe and Israel, underwent PVI only RF ablation for PAF (N=113), early PsAF (N=79), and non-early PsAF (N=108). The average age was 62.0 ± 9.5 years and 70.3% (211/300) were male. SR maps and AF maps were available and evaluated in HDW and SD for 196 subjects (65.3%) (63 PAF, 65 early PsAF, 68 non-early PsAF). Mean LA surface area was 108.8 cm² and mean mapped surface area ranged from 83.2 to 89.5 cm². HDW maps showed less low voltage area compared to SD in all subgroups, both in AF and in SR (Figure). For example, in AF with a low voltage cutoff of 0.5 mV, mean low voltage area was 49.8 cm² using SD and only 45.6 cm² using HDW (p&amp;lt;.0001). Similarly, in SR with a low voltage cutoff of 0.5 mV, mean low voltage area was 16.1 cm² using SD and only 12.6 cm² using HDW (p&amp;lt;.0001). HDW showed significantly less low voltage area than SD in SR for all measured voltage cutoffs from 0.1 mV to 1.5 mV. On average, non-early PsAF subjects had a larger low voltage area than early PsAF subjects and PAF subjects in both SR and AF. In SR HDW, non-early PsAF subjects had 15.6 cm² under 0.5 mV, early PsAF subjects had 12.4 cm², and PAF subjects had 9.2 cm² (p=.0316). In AF HDW, non-early PsAF subjects had 56.6 cm² under 0.5 mV, early PsAF had 42.8 cm² and PAF subjects had 35.4 cm² (p&amp;lt;.0001). Conclusion Non-early PsAF subjects had the largest low voltage area on average compared to both early PsAF and PAF subjects in this study. Using HD grid, HDW provided better low voltage area characterization compared to SD in both SR and AF. The final results of this study will suggest whether an HDW substrate characterization of low voltage area can predict recurrences after a single PVI-only strategy procedure.

Determination of a Wear Law for Uncoated Cutting Tools

The wear of cutting tools is one of the main current problems, especially when it comes to new materials called "difficult to machine" or with high added value. Tool wear is caused by extreme thermomechanical loads applied to the contact areas of tool chips and tool parts. During milling, turning or drilling operations, for example, large deformations, high deformation rates and high temperatures can be observed near the surface of the cutting tool. The objective of our work is to respond to the problem of abrasion wear by developing a predictive tool, based on knowledge of the physical and tribological mechanisms of workpiece-tool contacts, allowing us to quantitatively estimate the wear of the tool and its service life. To achieve this, we base our approach on previous studies carried out in the field of machining and metalworking. The modeling work was first applied to the wear case, then extended to the study of the crater wear occurring on the cutting face. By taking into account the mechanical load applied and the geometry of the contacts involved (plane-plane contacts), we have developed a two-dimensional approach in orthogonal cut configuration.

Spin–orbit torque driven skyrmion motion under unconventional spin Hall effect

The effective control of skyrmion motion is a critical aspect for realizing skyrmion-based devices. Among the potential directions, the use of current induced spin–orbit torque (SOT) is energetically efficient. However, the conventional heavy metals with high crystal symmetry limit the charge-to-spin conversion to the orthogonal configuration, which causes the skyrmions to deflect from the electrical current direction with a finite skyrmion Hall angle. Here, we investigate the SOT driven skyrmion motion under unconventional spin Hall effect. We systematically study the effect of a noncollinear low-symmetry spin source layer with spin moments mixed by Rashba-like S y , Dresselhaus-like S x and out-of-plane like S z on skyrmion features (velocity, diameter and Hall angle) stabilized in a ferromagnet/WTe2 heterostructure. Our results may provide a new degree of freedom for controlling the skyrmion Hall angle, and can open the way for the discovery of new ferromagnetic multilayer where the skyrmion Hall angle is suppressed by the proper design of different SOT driven forces.

Experimental and numerical study on the low-velocity impact response of thermoplastic composite corrugated sandwich panels

Composite corrugated sandwich structures have a wide range of applications in aerospace field, and the loss of structural load carrying capacity due to low-velocity impact damage has become one of the main threats in practical applications. In this study, the impact resistance of corrugated sandwich panels prepared from thermoplastic composites (TPC) under low-velocity impact loading was investigated. Through a series of drop-weight experiments and finite element simulations, the impact response process and damage morphology of the thermoplastic composite sandwich panels were obtained, and the effects of different impact energy and different core arrangements on the energy absorption performance of the structure were explored. Finally, a parametric analysis of the perpendicularly-arranged double-layered corrugated sandwich panel was carried out. The results show that thermoplastic composite sandwich panels exhibit an overall collapse response rather than localised damage, and the structure maintains good integrity and stability. The perpendicularly-arranged sandwich panels rely on the orthogonal configuration characteristics to provide optimum impact load carrying capacity, their impact resistance can be further improved by increasing the thickness of top face-sheet and reducing the thickness of the middle face-sheet at the same time. This provides a basis for promoting the application of TPC in engineering and the design of sandwich structures.

Supercurrent diode effect, spin torques, and robust zero-energy peak in planar half-metallic trilayers

We consider trilayer ${\mathrm{F}}_{1}{\mathrm{F}}_{2}{\mathrm{F}}_{3}$ Josephson junctions that are finite in two dimensions and have arbitrary magnetizations in each ferromagnet ${\mathrm{F}}_{i}\phantom{\rule{0.28em}{0ex}}(i=1,2,3)$. The trilayers are sandwiched between two $s$-wave superconductors with a macroscopic phase difference $\mathrm{\ensuremath{\Delta}}\ensuremath{\varphi}$. Our results reveal that when the magnetizations have three orthogonal components, a supercurrent can flow at $\mathrm{\ensuremath{\Delta}}\ensuremath{\varphi}=0$. With our generalized theoretical and numerical techniques, we study the planar spatial profiles and $\mathrm{\ensuremath{\Delta}}\ensuremath{\varphi}$ dependencies of the charge supercurrents, spin supercurrents, spin torques, and density of states. Remarkably, upon increasing the magnetization strength in the central ferromagnet layer up to the half-metallic limit, the self-biased current and induced second harmonic component become dramatically enhanced while the critical supercurrent reaches its maximum value. Additionally, for a broad range of exchange-field strengths and orientations, the ground state of the system can be tuned to an arbitrary phase difference ${\ensuremath{\varphi}}_{0}$. For intermediate exchange-field strengths in the middle layer ${\mathrm{F}}_{2}$, a ${\ensuremath{\varphi}}_{0}$ state can arise that creates a superconducting diode effect, whereby $\mathrm{\ensuremath{\Delta}}\ensuremath{\varphi}$ can be tuned to create a one-way dissipationless current flow. The spin currents and effective magnetic moments reveal a long-ranged spin torque in the half-metallic phase. Moreover, the density of states unveils the emergence of zero-energy peaks for the mutually orthogonal magnetization configurations. Our results suggest that this simple trilayer Josephson junction can be an excellent candidate for producing experimentally accessible signatures for long-ranged self-biased supercurrents and supercurrent diode effects.

Flutter performance of shape memory alloy-embedded 3D woven flexible composite plate under subsonic flow

Recently, 3D composites have gained prominence over 2D composites due to their remarkable through-the-thickness reinforcement that enhanced performances of structures subject to multi-directional stress conditions. However, it is at the expense of reduced in-plane properties. 3D composites also increased damage tolerance due to their high impact and delamination resistance properties, which are susceptible in 2D composites. In aeronautics, both are major concerns in primary structures such as lifting and control surfaces due to high vibrational loads from the airflow. Advancements in the aeroelasticity of aircraft structures show an increasing trend in using smart materials with composite structures for improved aeroelastic performance. An example is combining shape memory alloys (SMAs) with composites for improving damping, stiffness, and vibrational characteristics by utilizing stress generation and strain accommodation properties of SMAs in response to temperature and load, respectively. Published works are mostly numerical in nature, and experimental research is noticeably lacking as aeroelasticity is multidisciplinary and involves both structural and aerodynamic methodology. In this work, 3D composites with embedded SMA wires (for improved in-plane properties) are evaluated in terms of flutter performance in wind tunnel flutter testing under low airspeed conditions. Three 3D orthogonal interlock configurations with a different interlocking pattern of yarns with SMA wire were considered. These 3D configurations are layer-to-layer (L2L), through-the-thickness (TT), and a modified interlock (MF) structure that provides the strongest grip to SMA wire than L2L and TT. The effect of SMA positioning, at mid and near to trailing and leading edges of the cantilevered composite plate, on the aeroelastic flutter properties is also investigated. Results showed that activating SMA wires embedded in 3D structures have significantly improved post-flutter properties while there is a decrement in flutter speed and flutter frequency due to increased flexibility of deflected plate in the airflow by SMA-induced stresses. Among 3D structures, L2L with SMA near to trailing edge showed significant improvement in post-flutter properties by decreasing 22.2% in twist limit cycle oscillation (LCO) amplitude while L2L with SMA at mid showed a decrement of 9.5% for bending LCO amplitude. Hence, this work showed that embedding SMA is beneficial for mitigating the post-flutter vibrations but at the consequence of reduced flutter speed and frequency of flexible composite plate.

A self-adhesion criterion for slanted micropillars

Micropillar arrays see use in many fields such as biochemistry, mechanobiology, microfluidics, and micro/nanotechnology via applications like carbon nanotube forests and bioinspired fibrillar adhesives. In these fields, it is commonly desirable to either pack the micropillars as densely as possible or manufacture them to be as long/compliant possible. A barrier to either aim is the phenomenon of self-adhesion, where adjacent micropillars adhere to each other due to Van der Waals forces. In this paper, with self-adhesion as the limiting constraint, we show that longer, more compliant, and/or more densely packed micropillar arrays can be made by slanting the micropillars. From their typical orthogonal configuration, small inclinations produce an increment in micropillar packing and length up to a critical (optimum) angle, beyond which significant slanting produces a reduction in both. For parameter values typical of bioinspired fibrillar adhesives, we estimate that slanted micropillars arranged in a rectangular (triangular) lattice can improve in density by 10% (20%). Slanted micropillars also have increased compliance to loads applied orthogonally to the substrate (we refer to this as ‘orthogonal compliance’), achieved by engaging bending over axial deformation modes. This is particularly useful in fibrillar adhesives for conformation to surface roughness, hence increasing the overall adhesive strength. Our model provides a quantitative tool for the design of slanted micropillar arrays and computes the resulting enhanced array-properties.

A single-beam dual-axis atomic spin comagnetometer for rotation sensing

We describe a dual-axis atomic spin comagnetometer for rotation sensing using a single laser beam. A circularly polarized laser is used to pump the co-located atomic ensembles of alkali metal and noble gas and probe their gyroscopic precession at the same time, which is different from the traditional two-beam orthogonal pump-probe configuration. Combined with magnetic field modulations perpendicular to the laser propagating direction, the comagnetometer could measure dual-axis rotation rates simultaneously. This system is demonstrated theoretically and experimentally. A rotation sensitivity of 5.1 × 10–7 rad s−1 Hz−1∕2 and a bias instability of 0.016 °/h have been achieved. The theory and method presented here shed light on the way to miniaturize the comagnetometer with high precision for practical applications.

Spin Transfer Torque Oscillation in Orthogonal Magnetization Disks

We numerically demonstrated the spin transfer torque oscillation (STO) in a magnetic orthogonal configuration by introducing a 90° magnetic coupling. In our model, the multilayer consists of a top layer with in-plane magnetic anisotropy, a nonmagnetic spacer, and a bottom layer with perpendicular magnetic anisotropy. The advantage of utilizing the orthogonal configuration is the high efficiency of spin transfer torque but it is difficult to stabilize STO. By introducing 90° magnetic coupling into the trilayer of FePt/spacer/Co <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">90</sub> Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sub> , or Ni <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">80</sub> Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">20</sub> or Ni, a stable STO in an orthogonal configuration was realized. When the top layer was Ni with low levels of saturation magnetization, a small damping constant, and a small anisotropy, it exhibited high frequency and low amplitude. This indicates the possibility of controlling the STO frequency. Moreover, the STO frequency was increased by enhancing the 90° coupling. The combination of the orthogonal magnetization structure and 90° magnetic coupling is an effective approach to obtain a stable spin transfer torque oscillator with high frequency.

Cross sections and transport coefficients for electrons in C2H6O and its mixtures with Ar and Ne

In this paper, we show and discuss a set of cross sections for electron collisions with dimethyl ether (DME, C2H6O) obtained by the standard swarm analysis of experimental data for drift velocities and ionization coefficients measured in pure DME and its mixtures with Ar and Ne by E. Oettinger and coworkers. While the existing cross section set gave relatively good predictions for drift velocities, it proved necessary to modify the inelastic cross sections in order to achieve a better agreement with drift velocities in gas mixtures and a good agreement for the ionization coefficient. Furthermore, the derived set of cross sections was used to calculate the electron transport and rate coefficients under the influence of a constant electric field and crossed electric and magnetic DC and RF orthogonal configuration fields. The effect of the magnitude and frequency of the fields on electron transport was studied separately. Our work has resulted in a database of collision and transport data which can be used in modeling of both DC and RF discharges and plasma applications containing pure DME and its mixtures.Graphical abstract

Raman spectroscopy studies of black phosphorus

Black phosphorus has important applications in many fields such as optics, optoelectronics and thermals. Many of its excellent properties are related to its special anisotropy. In this work, we adopted Raman spectroscopy, which can obtain fast response optical signals without destroying the structure of the sample, to identify its crystal orientation and explore its thermal and SERS properties. We successfully distinguished the armchair and zigzag directions of black phosphorus by angle-resolved polarized Raman spectroscopy of Ag mode in a less studied orthogonal polarization configuration. Then we used temperature dependent Raman spectroscopy to study its thermal properties. It is found that the first order temperature coefficients of its three Raman vibration modes Ag1, B2g, and Ag2 are −0.0133 cm−1 K−1, −0.0232 cm−1 K−1 and −0.0229 cm−1 K−1, respectively for the 3.2 nm sample. Furthermore, we studied the surface enhancement effect of black phosphorus with different thicknesses as SERS substrates. We found that few-layer black phosphorus has better enhancement effects and its limit of detection for MB and CV are both 10-6M. The analytical enhancement factor of black phosphorus substrates on CV can achieve 1.2 × 103 by calculation. These methods can be extended to other similar two-dimensional materials.

Systematic Design of Multimode Antennas for MIMO Applications by Leveraging Symmetry

A systematic procedure for constructing orthogonal antenna ports on arbitrary symmetric multimode antennas is proposed. The procedure is based on the projection operator method from group theory. With this method, optimal orthogonal port configurations are generated analytically. Electromagnetic simulations, modal analyses, or optimization techniques are not required. The optimal port configurations are solely governed by the symmetry of an antenna and can thus be considered as <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">a priori</i> knowledge. Accordingly, this knowledge is available right from the beginning of the design process and can be purposefully used to compare different suitable antenna geometries with respect to the practical implementation effort. The procedure is illustrated by means of an application example resulting in a complete prototype of a six-port multimode antenna.

Highly efficient and stable deep-blue OLEDs based on narrowband emitters featuring an orthogonal spiro-configured indolo[3,2,1-de]acridine structure.

High-efficiency and stable deep-blue bottom-emitting organic light-emitting diodes with Commission Internationale de l'Eclairage y coordinates (CIEys) < 0.08 remain exclusive in the literature owing to the high excited-state energy of the emitters. Here, we propose the utilization of narrowband emitters to lower the excited-state energy for stable deep-blue devices by taking advantage of their high color purity. Two proof-of-concept deep-blue emitters with nitrogen-containing spiro-configured polycyclic frameworks are thereafter developed to introduce a multi-resonance effect for narrow emissions and sterically orthogonal configurations for alleviated molecular interactions. Both emitters show bright ultrapure deep-blue emissions with an extremely small full-width-at-half-maxima of only 18–19 nm, which can be maintained even in heavily doped films. Small CIEys of 0.054 and 0.066 are therefore measured from the corresponding electroluminescence devices with peak energies of only 2.77 eV (448 nm) and 2.74 eV (453 nm), accounting for the remarkably long LT80s (lifetime to 80% of the initial luminance) of 18 900 and 43 470 hours at 100 cd m−2, respectively. Furthermore, by adopting a thermally activated delayed fluorescence sensitizer, impressive maximum external quantum efficiencies of 25% and 31% are recorded respectively, representing state-of-the-art performances for deep-blue devices.

Design of 8-port compact hybrid fractal UWB MIMO antenna with a conjoined reflector-ground integration for isolation improvement

In this article, a compact 8-port UWB MIMO antenna was proposed to operate from (2.5–24) GHz with 162.2% impedance bandwidth. To achieve space diversity, i.e., maximum antenna elements accomodated in a premium foot-print, each radiating pairs are designed with self-similar hybrid geometry and oriented in side-by-side orthogonal configuration. The substrate corners are cut-out for maximum free space radiation and volumetric reduction. The isolation improvement mechanism is achieved by conjoining an annular reflector at top with the ground plane via metallic vias. The metal vias magnetically couple reflector and the ground plane into a connected topology. The annular reflector has dual-purpose, firstly, the contra-cyclic surface current symmetry improves the lower mode impedance matching and secondly, port-isolation is achieved (>22 dB) by electrically self-neutralize near-field radiated currents due to contra-rotational E-field NULL distributions. The antenna MIMO diversity performances show good attributes for indoor and outdoor wireless environments. To validate, a prototype antenna of size 48 mm × 48 mm (0.4λ×0.4λ,λ = operating wavelength at 2.5 GHz) was fabricated and measured. The simulated and measured results has good agreements to be explored in UWB MIMO systems, microwave telemetry, tracking and RF doppler sensor applications.

A Prospective Study on the Functional and Radiological Outcomes of AO Type C Distal Humerus Fractures in Adults Treated Surgically with Bicolumnar Fixation

Purpose: To study the functional and radiological outcomes of AO type C distal humerus fractures (DHFs) in adults treated surgically with bicolumnar fixation.&#x0D; Methods: A prospective study of 30 adult patients with AO/OTA type C fractures of the distal humerus treated operatively with bicolumnar fixation between September 2018 to December 2020 at Sree Balaji Medical College &amp; Hospital, Chennai was performed. Closed distal humerus fractures with intra-articular extension were fixed with bicolumnar plating, with orthogonal or parallel configuration of plate fixation decided intra-operatively. This was achieved in all patients after performing an olecranon osteotomy for better exposure of the fracture site, which was later fixed with either CC screws or K-wires with tension band wiring. The functional and radiological outcomes in this study group were assessed on regular post-operative follow-up. The Mayo Elbow Performance Score (MEPS) was used to evaluate the functional outcomes in our patients.&#x0D; Results: The mean age of the patients was 44 years, with 18 (60%) males and 12 (40%) females in the study. The right-sided elbow was more frequently involved (57%) in our study. The most common mode of injury was Motor Vehicle Accident (MVA) (14 cases; 47%), while domestic fall contributed to 10 (33%) cases. Fall from height and direct trauma to the elbow made up the rest of the cases, with a 10% incidence each. A majority of cases (22 cases; 73%) showed radiological union between 12-16 weeks post-operatively, whereas 8 cases (27%) united between 17-21 weeks. The Mayo Elbow Performance Score (MEPS) used to assess the functional outcome showed excellent results in 25 (83%) cases, good and fair results in 2 (7%) cases each, and a poor outcome in 1 (3%) case.&#x0D; Conclusion: For satisfactory results in intraarticular fractures of the distal humerus treated with bicolumnar plating, thorough pre-operative planning, posterior surgical approach with adequate exposure via olecranon osteotomy, anatomical inter-fragmentary stabilization by dual plating, and early post-operative mobilization with physiotherapy are important steps to be followed.