Full Ring Research Articles

Clinical Application and Evaluation of Specialised Ring Fixators for the Management of Upper and Lower Limb Bone Fractures in Dogs

Present study was conducted on nine-clinical cases of humerus (n=4), femur (n=3) and radius-ulna (n=2) fractures in dogs of either sex, weighing 5.5 to 18 kg. Both closed (n=6) and open (n=3) fractures were treated in this study. The fracture was reduced and stabilized by transfixation using modified ring fixators. Semicircular (n=4) and hybrid fixators (n=5) were used for upper limb and lower limb bones respectively. The main component of fixator i.e. aluminium rings were designed locally at Bikaner using 4-mm aluminium sheets and fabricated accordingly. Full rings were used for distal radial (n=2) and distal femoral (n=1) fractures whereas semicircular rings were made through cutting the full ring during surgery for specific humeral (n=4) and femoral (n=2) fractures. Specialised wire fixation bolt (iron based; weighing 5.5g) was also designed locally at Bikaner for transcortical pin and ring articulation. Humeral and distal femoral fractures are challenging while bone plating of distal radial fracture demands further surgeries therefore external fixators were modified and applied in present study. Operated limbs were evaluated clinically with serial postoperative radiographs at regular intervals. Fixator-assembly evaluation and functional recovery of operated limbs were considered as objectives of this study.

Axial and azimuthal development of disturbance waves in annular flow in a horizontal pipe

Transformation of gas-liquid flow in a horizontal pipe is investigated during the transition from stratified to annular flow pattern. Using Brightness-Based Laser-Induced Fluorescence technique, spatiotemporal evolution of liquid film thickness is analyzed over the downstream distance range of about 900 mm (45 pipe diameters), starting from the inlet. The measurements are carried out for three values of azimuthal angle θ: 0 (pipe bottom), 90°, and 180°, to track the circumferential spreading of liquid film and disturbance waves. At large gas velocities, thin liquid film is dragged upwards before the formation of large waves. The disturbance waves are created at the pipe bottom and spread circumferentially as they propagate downstream, over the already-wetted pipe walls. At large enough liquid flow rates, the spreading disturbance waves reach the pipe ceiling and form full rings around the circumference. The frequency and velocity of the disturbance waves eventually become the same around the pipe circumference; the disturbance wave amplitude and the base film thickness decrease with θ. The base film is more uniform around the circumference compared to the wave amplitude. At lower liquid flow rates, the disturbance waves cover only a part of pipe circumference. Their edges demonstrate oscillatory circumferential spreading, which ends by deceleration and decay of the edges. The upper part of the pipe may be wetted by a thin base film layer, covered only with ripples, or remain dry. At low gas speeds and large liquid flow rates, occasional splashing of large waves over the pipe ceiling without pre-wetting by the thin film is possible; however, the remaining film drains downward and no stable annular film is maintained. Liquid droplets, entrained from the pipe bottom and depositing in the upper parts of the pipe, are gathered in trains of creeping pendant droplets at the very top part of the pipe; no continuous wetting is achieved due to droplet deposition.

Ultrasound computed tomography image reconstruction with multi-mode aperture matching of ring array

Ultrasound computed tomography (USCT) imaging with a ring array holds significant potential for the inspection of small animals, breast tissue, and industrial components. Despite its promise, current techniques face challenges in terms of image quality. This paper presents a multi-mode aperture matching method for USCT image reconstruction with a ring array, aiming to enhance imaging performance. The proposed method utilizes a full ring transducer to transmit signals with a designated sub-aperture, while the receiving sub-aperture is adjusted based on the reference center element. By altering the transmitting and receiving sub-apertures under different conditions, specific imaging effects can be achieved. Experimental validation was conducted using a hair strand of 0.03 mm diameter placed at both center and eccentric positions within the ring array, in conjunction a breast phantom. Image resolution and contrast were assessed using full width at half maximum and contrast-to-noise ratio metrics. The results identified optimal transmitting and receiving sub-aperture matching modes for imaging the hair strand at various positions, and demonstrated the impact of this method on imaging targets at different positions within the breast phantom. These findings and experimental validations provide significant implications for enhancing imaging performance in USCT with a ring array.

Implementation and validation of a bonded particle model to predict rheological properties of viscoelastic materials

This work focuses on implementing a particle-based method able to characterize viscoelastic materials whose rheological properties, such as storage modulus G’ and loss modulus G”, are known. It is based on the Bonded Particle Model, with the elastic constitutive relation here substituted with a viscoelastic one to capture time-scale effects. The Burgers model, vastly used in literature to model viscoelastic systems, is discretized and implemented. The test case used for calibration comprises of a cubic lattice, sheared with a periodic motion, to mimic the effect of a shear rheometer. After appropriate filtering of the stress response, the rheological properties are obtained, highlighting the effect of the lattice geometry, as well as the particle size, on the accuracy of the model. Moreover, the Burgers parameters are calibrated by analytically fitting the experimental dataset, showing the limitation of the Burgers model. The micro-contact parameters are obtained from the macro parameters through appropriate scaling. After completing a frequency sweep, the simulated G’ and G” show a relatively large error, around 25% for G’ for example. For this reason, a more robust model, namely the Generalized Maxwell Model, has been implemented. The calibration procedure is performed in the same fashion as for the Burgers model. Moreover, the tangential micro-contact parameters are scaled w.r.t. the normal ones. This scaling parameter, called α, is calibrated by minimizing the Root Mean Square Error between simulation and experimental data, giving errors below 10% in both G’ and G” for a large dataset. Additionally, a full ring plate-plate rheometer setup is simulated, and the simulation is compared with the given experimental dataset, again finding a good agreement.

Abstract 16946: The Optimal Surgical Procedure of Mitral Valve Repair According to Risk Analysis of Postoperative Functional Mitral Stenosis

Background: Functional mitral stenosis (FMS) after mitral valve repair (MVr) is associated with pulmonary hypertension in the late period, increasing the risk of re-operation and deterioration of long-term outcomes. However, the risk factors for FMS after MVr, especially the impact of surgical procedures, have not been thoroughly investigated. Hypothesis: We hypothesize that procedures of valve repair, including prosthetic ring orifice area (ROA), may be associated with FMS in the late period. Methods: We retrospectively evaluated 205 patients who underwent MVr using full annuloplasty rings between 2011 and 2021 at our institution. FMS was defined as mean trans-mitral pressure gradient (TMPG) ≥8 mmHg measured by annual echocardiography. ROA was determined by calculating the internal area of each valve type and size. Perioperative factors such as repair techniques, ROA, and ROA divided by BSA (ROAi) were used to analyze risk factors for FMS. The mean follow-up period was 4.8±0.4 years. Results: MVr was performed using artificial chordae in 110 cases and intervention in valve leaflet in 83 cases (resection suture: 43, cleft closure: 26, plication: 12, and edge-to-edge repair: 8). We also utilized semi-rigid full ring in all cases (26 or less: 15, 28: 53, 30: 73, 32: 49, 34 or more: 15). We identified postoperative FMS in 23 cases (11.2%, 2.5±0.9 years after MVr) with TMPG of 9.0 ± 0.7 mmHg. In the FMS group, decreasing TR-PG in the late period was not achieved after MVr. TR-PG in the late period was also significantly higher in the FMS group (28.3 ± 5.8 vs. 20.3 ± 2.1 mmHg, p=0.01). The freedom from re-operation for MV and re-hospitalization for heart failure rate was not significantly different in the two groups (93.6% vs. 95.5%, p=0.32, 87.7% vs. 90.6%, p=0.36, respectively). However, the freedom from MACE rate was lower in the FMS group (81.4% vs. 86.3%, p=0.11). Univariate analysis demonstrated that intervention in valve leaflet (OR 2.53, p=0.04) and ROAi (OR 0.98, p=0.005) were significant risk factors for FMS. Conclusion: Although further follow-up is mandatory, these results suggested that the use of sufficiently large prosthetic ring and avoidance of intervention in valve leaflet are efficient for preventing FMS and improving clinical outcomes after MVr.

Detection of brazing defects in stainless steel core plate using the first peak value of pulsed eddy current testing signals

As a novel building structure element, stainless steel core plate (SSCP) has seen growing application in modular construction. It is composed of two stainless steel skin panels and a number of stainless steel core tubes, which are brazed by elevated temperature inert gas. The underlying defects in brazing joints severely damage the SSCP’s structural integrity and weaken its mechanical properties. In this study, a nondestructive testing (NDT) method based on pulsed eddy current testing (PECT) was employed to contactlessly detect the missing solder and non-bonding brazing defects from the plate surface. The defect-free and defective brazing joints are simplified to stratified structures and analytical modeling for a PECT probe over the brazing joint is thus performed. The time-domain features of the calculated PECT signal due to the structure parameter variation are investigated. The first peak value is selected to characterize the brazing quality due to its distinct variation w.r.t. well-bonded brazing, missing solder, non-bonding and skin panel. Experiments are also carried out to validate the analytical modeling. With the aid of an industrial robotic arm, one-dimensional (1D) line-scan and two-dimensional (2D) planar scan of the PECT probe over the SSCP specimen are implemented and the detection results are represented in images. In contrast to the well-bonded joint, the brazing joints with missing solder defects are imaged as notched rings, on which the notch orientations and sizes agree with the actual openings of the brazing foils, while the non-bonding brazing joint is imaged as a full ring with faded color. The proposed method shows a promising aspect in practical application for automated NDT of the brazing defects in SSCPs.

Analysis of the Measured FDG Uptake from the First-in-Human Clinical Trial of Biology-Guided Radiotherapy

The RefleXion X1 system is a novel linear accelerator equipped with dual 90° PET arcs incorporated into its architecture to capture emissions from tumors and designed to respond by directing the radiation beam towards target. This study reports on the measured FDG uptake from the first in human multi-institutional clinical trial (BIOGUIDE-X) evaluating the performance and safety of the RefleXion X1 PET-LINAC. A total of nine patients treated with stereotactic body radiotherapy (SBRT) for lung (5) and bone (4) tumors were enrolled in the Cohort II of this study after screening their pre-study diagnostic PET/CT, acquired up to 60 days prior to enrollment, to ensure their tumor size between 2 to 5 cm and SUVmax >6. After CT simulation, the tumor and OARs were delineated, and patients had a 4-pass Imaging-only (BgRT Modeling) PET/CT acquisition on the X1 system to generate biology-guided radiotherapy (BgRT) plans. Before the patients' first and last SBRT fractions, they were injected with FDG, and short PET pre-scan (1-pass) was performed on the X1 followed by a long-PET acquisition (4-pass) to emulate the expected BgRT dose distribution without firing beam. Patients were also imaged on a third-party diagnostic PET/CT scanner after the last-fraction X1 scan. This study compares the SUVmax from the screening PET/CT, X1 Imaging-only scan, X1 PET pre-scan and long scan before the first and last-fractions, and final diagnostic PET/CT. The median time from injection to PET imaging was 84 ± 15.4 mins for X1 Imaging-only (used for generating BgRT plans), 77 ± 21.6 mins for X1 pre-scan (safety check before treatment start), 108+/- 22 mins for X1 long-PET (used to emulate treatment delivery), and 161 ± 23 mins for final diagnostic PET. For a nominal 10 mCi injection, the mean SUVmax for screening imaging performed on the diagnostic PET/CT was 10.8 ± 4.3. For a 15 mCi nominal injection, the mean SUVmax calculated on the X1 was 5.3 ± 2.6, 5.4 ± 2.0, 5.5 ± 2.6, 5.2 ± 1.8 and 5.4 ± 2.2 for the Imaging-only, first-fraction PET pre-scan, first-fraction long PET scan, last-fraction PET pre-scan, and last-fraction long PET scan, respectively. The overall median SUVmax for all patients across all timepoints and scans with X1 was calculated to be 4.8 with a range of 2.4 to 9.8. The median SUVmax for the diagnostic PET/CT scan after the last fraction X1 scan was 15.8 with a range of 8.5 to 27.7. The dual PET arcs and limited axial extent of the X1 PET subsystem results in lower system sensitivity in comparison to diagnostic PET scanners equipped with full ring and larger axial extent, as expected. With the same FDG injection, the RefleXion X1 produced SUVmax values that were 30.4 % of the diagnostic PET/CT scanners' values. Nevertheless, the X1 collected sufficient emission data to enable successful completion of emulated BgRT deliveries that met dose accuracy criteria in a clinical setting.

Role and Effects of Yoga on Sports Performance of Olympic Participants from the State of Haryana- A Study

The purpose of this study was to evaluate, how Yoga can benefit to the body and mind of a sportsperson. Yoga is the science of life and the art of living. Yoga arose in the age of the Vegas and upanishads.It is India's oldest scientific, perfect spiritual discipline. Yoga is a method of training the maind and developing. Overwhel ming at first to find a style of yoga,that resonates with you.you r a competitive sport man ,it is best to tailor your yoga practices of your training schedule because a particular sport can develop certain muscle groups while ignoring others.over time this process causes imbalances in the muscles and joints, leading to overuse injuries. Yoga helps the muscles, tendons,and ligaments move through a full rang of motion , thus cultivating balance and core strength which is a huge benefit to athletes in their choosen sports .Another essential element in yoga is breath work (preanayam). The attention to breath during yoga can be considered one of the most important benefits to players to stay focused and centered through uncomfortable poses by consenting on even in halations and exhalation sets-up the athletes to stay focused during a race or challenging workout .The mind and body connection in yoga is essential to helping sports men develop mental acuity and concentration. Yoga helps you to relax not just tight muscles., but also anxious and over stressed mind .Yoga develop immunity and resistance in human body and helps the between body and mind balance . You can be benefits in sports men performance . So by ending adding yoga to the training plan will anhance the performance and prevent injury to a sports person. Keywords : Yoga, balance, flexibility, focus, relax, sports person etc.

The impact of annuloplasty ring or band implantation on post-repair mitral valve hemodynamic performance.

The clinical importance of optimal post-repair mitral valve diastolic performance is increasingly being recognized. The haemodynamic effect of a partial annuloplasty band implantation, in comparison to a full ring, remains insufficiently explored. Patients undergoing mitral valve repair for pure degenerative disease between 2011 and 2019 at two experienced heart valve centres were eligible for inclusion. Exclusion criteria were concomitant procedures other than tricuspid valve repair and ablation procedures for atrial fibrillation. Pre-discharge and follow-up echocardiograms (1-4 years after surgery) were analyzed to assess haemodynamic mitral valve performance. Of 535 patients meeting the inclusion criteria, 364 (68.0%) patients underwent full annuloplasty ring and 171 (31.0%) partial band implantation. On predischarge echocardiogram, post-repair mitral valve gradient and area did not differ between groups [2.89 mmHg (IQR 2.26-3.72) vs 2.60 mmHg (IQR 1.91-3.55), P = 0.19 and 1.98 cm2 (IQR 1.66-2.46) vs 2.03 cm2 (IQR 1.55-3.06), P = 0.15]. However, multivariable linear regression analysis demonstrated band annuloplasty as a determinant of larger valve area (coefficient 0.467 cm2, standard error 0.105, P < 0.001). On multivariable analysis, no significant impact on post-repair gradient was observed (-0.370 mmHg, standard error 0.167, P = 0.36). At follow-up, the differences between groups disappeared and multivariable regression analysis failed to demonstrate a significant impact of annuloplasty device type on mitral valve gradient (coefficient -0.095 mmHg, standard error 0.171, P = 1.00) or area (coefficient -0.085 cm2, standard error 0.120, P = 1.00). These results were confirmed with a linear mixed model analysis. Partial band annuloplasty was related to an improved haemodynamic profile directly after valve repair for degenerative disease but the effect was short-lived. Our results suggest that the type of annuloplasty device has no durable impact on diastolic valve performance.

Strongly Clean Matrix Rings over a Skew Monoid Ring

Let [Formula: see text] be a ring with an endomorphism [Formula: see text], [Formula: see text] the free monoid generated by [Formula: see text] with 0 added, and [Formula: see text] a factor of [Formula: see text] obtained by setting certain monomials in [Formula: see text] to 0 such that [Formula: see text] for some [Formula: see text]. Then we can form the non-semiprime skew monoid ring [Formula: see text]. A local ring [Formula: see text] is called bleached if for any [Formula: see text] and any [Formula: see text], the abelian group endomorphisms [Formula: see text] and [Formula: see text] of [Formula: see text] are surjective. Using [Formula: see text], we provide various classes of both bleached and non-bleached local rings. One of the main problems concerning strongly clean rings is to characterize the rings [Formula: see text] for which the matrix ring [Formula: see text] is strongly clean. We investigate the strong cleanness of the full matrix rings over the skew monoid ring [Formula: see text].

What Is the Optimal Mitral Valve Repair for Isolated Posterior Leaflet Prolapse to Achieve Long-Term Durability?

Background This study assessed risk factors for mitral regurgitation (MR) recurrence or functional mitral stenosis during long-term follow-up in patients undergoing mitral valve repair for isolated posterior mitral leaflet prolapse. Methods and Results We assessed a consecutive series of 511 patients who underwent primary mitral valve repair for isolated posterior leaflet prolapse between 2001 and 2021. Annuloplasty using a partial band was selected in 86.3%. The leaflet resection technique was used in 83.0%, whereas the chordal replacement without resection was used in 14.5%. Risk factors were analyzed for MR recurrence ≥grade 2 or functional mitral stenosis with mean transmitral pressure gradient ≥5 mm Hg using a multivariable Fine-Gray regression model. The 1-, 5-, and 10-year cumulative incidence of MR ≥grade 2 was 7.8%, 22.7%, and 30.1%, respectively, whereas that of mean transmitral pressure gradient ≥5 mm Hg was 8.1%, 20.6%, and 29.3%, respectively. Risk factors for MR ≥grade 2 included chordal replacement without resection (hazard ratio [HR], 2.50, P<0.001) and larger prosthesis size (HR, 1.13, P=0.023), whereas factors for functional mitral stenosis were use of a full ring (partial band versus full ring, HR, 0.53, P=0.013), smaller prosthesis size (HR, 0.74, P<0.001), and larger body surface area (HR, 3.03, P=0.045). Both MR ≥grade 2 and mean transmitral pressure gradient ≥5 mm Hg at 1 year post surgery were significantly associated with the long-term incidence of reoperation. Conclusions Leaflet resection with a large partial band may be an optimal strategy for isolated posterior mitral valve prolapse.

Multimedia display of wushu intangible cultural heritage based on interactive system and artificial intelligence

With the rapid development of the information age, various forms of digitalization have facilitated people’s various lives, but digitalization has also brought crisis to people. The most obvious is that in the digital era, the original living environment of intangible cultural heritage of martial arts and its traditional development and protection mode have become less and less compatible with the digital era. Therefore, its development is currently facing difficulties, even endangered problems. Based on this phenomenon, this paper combines artificial intelligence technology and interactive system to establish an intelligent multimedia display interactive system for intangible cultural heritage of martial arts. In this system, the martial artist's moving image can be captured by the action image acquisition device, and the collected image sequence can be calculated and analyzed. The system host “remembers” the martial artist’s action. The main functions of the system, such as random flow, click and zoom, multi-point movement and printing, are all in the charge of the picture control module; Video playback, full screen display and ring button control functions are mainly completed by the video control module. The experimental results show that the task time of using interactive system to locate visual objects with massive information in icon materials is significantly faster than that of using no interactive highlighting system. Therefore, we can preliminarily determine that the interactive system can improve the performance of target positioning in massive information. In this paper, the interactive system and artificial intelligence technology are applied to the intangible cultural heritage of martial arts, which has played a role in promoting its development.

Preliminary Report on Optical Coherence Tomography Angiography Biomarkers in Non-Responders and Responders to Intravitreal Anti-VEGF Injection for Diabetic Macular Oedema.

To identify optical coherence tomography angiography (OCTA) biomarkers in patients who were treated for diabetic macular oedema (DME) with intravitreal anti-vascular endothelial growth factor (VEGF) injections and compare the OCTA parameters between responders and non-responders. A retrospective cohort study of 61 eyes with DME who received at least one intravitreal anti-VEGF injection was included between July 2017 and October 2020. The subjects underwent a comprehensive eye examination followed by an OCTA examination before and after intravitreal anti-VEGF injection. Demographic data, visual acuity, and OCTA parameters were documented, and further analysis was performed pre- and post-intravitreal anti-VEGF injection. Out of 61 eyes which underwent intravitreal anti-VEGF injection for diabetic macular oedema, 30 were responders (group 1) and 31 were non-responders (group 2). We found that the responders (group 1) had a higher vessel density in the outer ring that was statistically significant (p = 0.022), and higher perfusion density was noted in the outer ring (p = 0.012) and full ring (p = 0.044) at levels of the superficial capillary plexus (SCP). We also observed a lower vessel diameter index in the deep capillary plexus (DCP) in responders when compared to non-responders (p < 0.00). The evaluation of SCP in OCTA in addition to DCP can result in a better prediction of treatment response and early management in diabetic macular oedema.

Applications of Hochschild cohomology to the moduli of subalgebras of the full matrix ring

Let Moldn,d be the moduli of rank d subalgebras of Mn over Z. For x∈Moldn,d, let A(x)⊆Mn(k(x)) be the subalgebra of Mn corresponding to x, where k(x) is the residue field of x. In this article, we apply Hochschild cohomology to Moldn,d. The dimension of the tangent space TMoldn,d/Z,x of Moldn,d over Z at x can be calculated by the Hochschild cohomology H1(A(x),Mn(k(x))/A(x)). We show that H2(A(x),Mn(k(x))/A(x))=0 is a sufficient condition for the canonical morphism Moldn,d→Z being smooth at x. We also calculate Hi(A,Mn(k)/A) for several R-subalgebras A of Mn(R) over a commutative ring R. In particular, we summarize the results on Hi(A,Mn(k)/A) for all k-subalgebras A of Mn(k) over an algebraically closed field k in the case n=2,3.

Flexible Total Ring Annuloplasty With Continuous Wrapping Suture Considering the Anatomy and Histology of the Tricuspid Valve.

About half of tricuspid valves (TVs) have 2 posterior leaflets, and the fibrous tissue of the tricuspid annulus is poor. Considering the anatomy and histology of the TV, we devised a secure ring annuloplasty technique. We herein report the outcomes of our continuous wrapping suture annuloplasty technique using a flexible total ring. We used a Tailor™ ring (Abbott, Chicago, IL, USA) as a full ring. The mark on the left side of the ring was fixed to the anteroseptal commissure, and the midpoint of the ring's markers was fixed at the center of the septal leaflet annulus. Using a continuous suture, all stitches were passed around the annuloplasty ring without penetration. One suture from the anteroseptal commissure ran toward the left side and another from the midpoint of the septal leaflet annulus ran toward the right, leading to annuloplasty without TV deformation. Eighty patients underwent TV repair with this technique. The tricuspid regurgitation (TR) score in all patients improved from 1.9 ± 0.7 to 0.8 ± 0.4 (P < 0.001) at 3 years postoperatively. The TR score of TVs with 2 posterior leaflets also improved from 1.9 ± 0.7 to 0.6 ± 0.4 after the operation and was unchanged during follow-up. The median follow-up period was 1.3 (0.5 to 2.0) years, and no patients required TV reoperation. The 3-year survival rate was 93%, and the 3-year rate of freedom from pacemaker implantation was 95%. The continuous wrapping suture technique using a flexible total ring is a useful procedure without TV deformation even when 2 posterior leaflets are present.

The PETcoil project: PET performance evaluation of two detector modules for a second generation RF-penetrable TOF-PET brain dedicated insert for simultaneous PET/MRI

Objective. We are developing a portable, ‘RF-penetrable’, brain-dedicated time of flight (TOF)-PET insert (PETcoil) for simultaneous PET/MRI. Approach. In this paper, we evaluate the PET performance of two fully assembled detector modules for this insert design outside the MR room. Main results. The global coincidence time resolution, global 511 keV energy resolution, coincidence count rate, and detector temperature achieved over 2 h data collection were 242.2 ± 0.4 ps full width at half maximum (FWHM), 11.19% ± 0.02% FWHM, 22.0 ± 0.1 kcps, and 23.5 °C ± 0.3 °C, respectively. The intrinsic spatial resolutions in the axial and transaxial directions were 2.74 ± 0.01 mm FWHM and 2.88 ± 0.03 mm FWHM, respectively. Significance. These results demonstrate excellent TOF capability and the performance and stability necessary for scaling up to a full ring comprising 16 detector modules.

Half-Ring Microlasers Based on InGaAs Quantum Well-Dots with High Material Gain

We report on half-ring lasers that are 100–200 µm in diameter and are fabricated by cleaving the initial full rings into halves. Characteristics of the half-ring and half-disk lasers fabricated from the same wafer are compared. The active area of the microlasers is based on the quantum heterostructures of mixed (0D/2D) dimensionality, referred to as quantum well-dots with very high material gain. Half-ring lasers show directional light emission and single-mode lasing near the threshold. A maximal continuous-wave output power of 76 mW is achieved for a half-ring that is 200 µm in diameter. Half-rings demonstrate better wall-plug efficiency as compared to half-disks. Lasing in pulse mode is observed up to 140 °C, the characteristic temperature is 100–125 K, depending on the half-ring size. P-side down bonding onto Si-board significantly improves power and temperature characteristics. In CW mode, lasing is maintained up to 97 °C, limited by active-area overheating.

Design of a Frequency Selective Rasorber Based on a Band-Patterned Octagonal Ring

In this study, a dual-polarization and low-profile frequency-selective rasorber (FSR) constructed from a novel band-patterned octagonal ring and dipole slot-type elements is investigated. We show the process of designing from a full octagonal ring to realize a lossy frequency selective surface of our proposed FSR, and it has a passband with low insertion loss between the two absorptive bands. An equivalent circuit for our designed FSR is modeled to explain the introduction of the parallel resonance. Surface current, electric energy, and magnetic energy of the FSR are further investigated to illustrate the working mechanism. Simulated results indicate that S11 < -10 dB bandwidth within 5.2-14.8 GHz, S21 > -3 dB passband within 9.62-11.72 GHz, lower absorptive bandwidth within 5.02-8.80 GHz, and upper absorptive bandwidth within 12.94-14.89 GHz are obtained under normal incidence. Meanwhile, our proposed FSR possesses the properties of dual-polarization and angular stability. To verify the simulated results, a sample with thickness of 0.097 λL is manufactured, and the results are experimentally verified.

Conformational dynamics control assembly of an extremely long bacteriophage tail tube

Tail tube assembly is an essential step in the lifecycle of long-tailed bacteriophages. Limited structural and biophysical information has impeded an understanding of assembly and stability of their long, flexible tail tubes. The hyperthermophilic phage P74-26 is particularly intriguing as it has the longest tail of any known virus (nearly 1μm) and is the most thermostable known phage. Here, we use structures of the P74-26 tail tube along with an invitro system for studying tube assembly kinetics to propose the first molecular model for the tail tube assembly of long-tailed phages. Our high-resolution cryo-EM structure provides insight into how the P74-26 phage assembles through flexible loops that fit into neighboring rings through tight "ball-and-socket"-like interactions. Guided by this structure, and in combination with mutational, light scattering, and molecular dynamics simulations data, we propose a model for the assembly of conserved tube-like structures across phage and other entities possessing tail tube-like proteins. We propose that formation of a full ring promotes the adoption of a tube elongation-competent conformation among the flexible loops and their corresponding sockets, which is further stabilized by an adjacent ring. Tail assembly is controlled by the cooperative interaction of dynamic intraring and interring contacts. Given the structural conservation among tail tube proteins and tail-like structures, our model can explain the mechanism of high-fidelity assembly of long, stable tubes.

The network structure of the corneal endothelium.

A generic network model is applied to study the structure of the mammalian corneal endothelium. The model has been shown to reproduce the network properties of a wide range of systems, from low-dimensional inorganic glasses to colloidal nanoparticles deposited on a surface. Available extensive experimental microscopy results are analyzed and combined to highlight the behavior of two key metrics, the fraction of hexagonal rings (p6) and the coefficient of variation of the area. Their behavior is analyzed as a function of patient age, the onset of diabetes, and contact lens wearing status. Wearing contact lenses for ∼10 years is shown to change the endothelium structure by the equivalent of ∼30 years contact lens-free. Model network configurations are obtained using a Monte Carlo bond-switching algorithm, with the resulting topologies controlled by two potential model parameters (the bond and angular force constants) and the Monte Carlo temperature. The effect of systematically varying these parameters is investigated. In addition, the effect of constraining the ring size distribution is investigated. The networks generated with relatively weak bond force constants are shown to correlate best with the experimental information. The importance of extracting the full ring size distribution (rather than simply the fraction of hexagons) is discussed.