Extra Structures Research Articles

Rouvière's Sulcus as a Landmark for a Safe Laparoscopic Cholecystectomy: An Interim Analysis of a Multicenter Cross-sectional Study on the Prevalence and Morphologic Type of Rouvière's Sulcus in the Italian Population.

Laparoscopic cholecystectomy is the gold standard in the treatment of symptomatic gallstones. The large number of gallbladders removed every year is not fully consistent with the excessively high incidence of iatrogenic bile duct injury (IBDI). Several strategies have been suggested to reduce this risk. Among them, the use of extra biliary anatomic structures, such as the Rouvière's sulcus, as a landmark to guide the surgeon during dissection has been proposed as a means to prevent IBDI. The main aim of the present paper is the evaluation of the prevalence of Rouvière's sulcus (RS) and its anatomic variants in a given population. This observational, cross-sectional, and multicenter study has been conducted at the Department of Digestive and Emergency Surgery of the "Azienda Ospedaliera Santa Maria," Terni (Italy), at the Department of Surgical Sciences of the "Azienda Ospedaliera Perugia," Perugia (Italy) and at the Department of Emergency and Trauma Surgery of the "Policlinico Umberto I," Rome (Italy). Intraoperative images of 111 patients undergoing laparoscopic cholecystectomy were analyzed to identify the presence and type of RS, according to the Singh-Prasad classification and the Dahmane classification. RS was present in 93 (83.8%) patients. Singh-Prasad type 1A is present in 48.4% of patients, type 1B in 25.8%, type 2 in 12.9% and type 3 in 12.9%. Dahmane's open type is present in 48.4% of patients and fused type in 51.6%. Due to its high prevalence, RS can be used as an anatomic landmark and probably reduces the incidence of IBDI during laparoscopic cholecystectomy.

A compact circularly polarized dielectric resonator antenna with MIMO characterizations for UWB applications.

Ultra-wideband (UWB) technology is extensively used in indoor navigation, medical applications, and Internet of Things devices due to its low power consumption and resilience against multipath fading and losses. This paper examines a multiple-input multiple-output (MIMO), circularly polarized (CP) dielectric resonator antenna for UWB systems. Compact form factor, high gain, wideband response, improved port isolation, and high data rates are the major design goals. This arrangement consists of two identical DRAs with self-decoupled orthogonal orientations eliminating the need for extra decoupling structures while achieving an impressive maximum isolation of 43 dB. The corner-edge feeding mechanism of the extended feedline generates two orthogonal E-fields, facilitating circular polarization. Additionally, a printed hook-shaped stub integrated with the ground plane enhances CP performance across the two operating bands without altering the DR structure. Fabrication and testing exhibit an impressive 133 impedance bandwidth (2.5-14 GHz) with high port isolation. For a 3 dB axial ratio reference, the single-element design exhibits axial ratio bandwidths (ARBW) of 1.2 GHz (3.6-4.8 GHz) and 0.8 GHz (9.3-10.1 GHz). Remarkably, the MIMO configuration achieves a single ARBW of 0.5 GHz (3.9-4.4 GHz). Detailed investigations of MIMO performance parameters, including diversity gain, envelope correlation coefficient, channel capacity loss, and total active reflection coefficient, underscore the design's efficacy, making it a good choice for UWB wireless applications.

Association between pseudoexfoliation syndrome and dyslipidemia: A case control study

: Pseudoexfoliation syndrome, also known as PEX 1, is a systemic micro fibrillopathy associated with ageing that is brought on by the gradual buildup of extracellular white and grey matter on various ocular and extra ocular structures. It is deposited in extra-ocular tissues such the heart, blood vessels, meninges, liver, and lungs. Numerous investigations have shown a connection between PEX and glaucoma. A person with PEX is typically thought to be at risk for acquiring glaucoma, and vice versa.Atherosclerosis is facilitated by dyslipidemia, which is an increase in plasma cholesterol, triglycerides (TGs), or both, or a low HDL level. A potential risk factor for the progression of cardiovascular disease is dyslipidemia. Numerous investigations have discovered abnormal lipid profiles in pseudoexfoliation syndrome patients, including elevated levels of triglycerides, cholesterol, and LDL. Due to the straight association between lipid levels, atherosclerosis, and cardiovascular risk, patients with PEX are shown to be at an elevated risk of cardiovascular and cerebrovascular events.To study the correlation between dyslipidemia and pseudoexfoliation syndrome in patients above 50 years of age and compare it with age matched controls.This case control study was conducted from November 2020 to November 2022 at SKIMS Medical College and Hospital, Srinagar and included 150 patients with PEX above 50 years of age and compared with age matched controls. In this study mean total cholesterol among cases was 176.88±34.76 mg/dl versus 172.94±51.51 mg/dl in controls. P-value for total cholesterol was statistically insignificant (0.438). Mean triglyceride level among cases was 180.11±54.70 mg/dl while as mean triglyceride level among controls was 163.14±46.21 mg/dl and P-value was found to be statistically significant. Mean LDL level among cases was 104.57±32.80 mg/dl while as in controls mean was 82.70±27.60 mg/dl. P-value for LDL levels was found to be statistically significant. Mean HDL levels among cases was found to be 41.93±8.94 mg/dl while as in controls mean was 39.67±13.73 mg/dl. P-value for HDL levels was statistically insignificant (0.09). Mean VLDL levels among cases was found to be 25.34±19.52 mg/dl while as in controls mean was 27.66±14.36mg/dl. P-value for VLDL levels was statistically insignificant (0.242).There is significant correlation between dyslipidemia and pseudoexfoliation syndrome in patients above 50 years of age.

Normative measurements of orbital structures on magnetic resonance images; a cross-sectional study with mini review of the literature.

Awareness of normative values of extra orbital structures would provide useful information to interpret the radiological images better and use them for diagnostic purposes. This study aimed to reveal the average values of major extraocular structures measured on magnetic resonance images. In this retrospective cross-sectional study, magnetic resonance (MR) images of 256 orbits of 128 patients were re-interpreted regarding the measurements of major orbital structures. Extraocular muscles, superior ophthalmic vein, and optic nerve-sheath complex were measured on orbital MR images of these patients. The data distributions were presented by box-plot analyses for each parameter, and the measurement results were analyzed regarding gender and age groups. Lateral rectus muscle thickness (LR), inferior rectus muscle thickness (IR), globe position (GP), and interzygomatic line (IZL) values were higher in the male group than in the female group (p values were < 0.001, 0.003, 0.020, and < 0.001 respectively). LR, the thickness of the superior group muscles (SUP GR), IR, superior oblique muscle thickness (SOBL), and the thickness of optic nerve-sheath complex (ON) values indicated a significant relationship between age groups. There was a significant, positive, and low-level correlation between age and LR, SUP GR, and IR values (p values were < 0.001, 0.001, and < 0.001, respectively). This study provides quantitative data on normative values of orbital structures with gender and age group comparisons. Clinicians or surgeons can easily use the measured values to gather diagnostic information from the orbital region.

PG-LBO: Enhancing High-Dimensional Bayesian Optimization with Pseudo-Label and Gaussian Process Guidance

Variational Autoencoder based Bayesian Optimization (VAE-BO) has demonstrated its excellent performance in addressing high-dimensional structured optimization problems. However, current mainstream methods overlook the potential of utilizing a pool of unlabeled data to construct the latent space, while only concentrating on designing sophisticated models to leverage the labeled data. Despite their effective usage of labeled data, these methods often require extra network structures, additional procedure, resulting in computational inefficiency. To address this issue, we propose a novel method to effectively utilize unlabeled data with the guidance of labeled data. Specifically, we tailor the pseudo-labeling technique from semi-supervised learning to explicitly reveal the relative magnitudes of optimization objective values hidden within the unlabeled data. Based on this technique, we assign appropriate training weights to unlabeled data to enhance the construction of a discriminative latent space. Furthermore, we treat the VAE encoder and the Gaussian Process (GP) in Bayesian optimization as a unified deep kernel learning process, allowing the direct utilization of labeled data, which we term as Gaussian Process guidance. This directly and effectively integrates the goal of improving GP accuracy into the VAE training, thereby guiding the construction of the latent space. The extensive experiments demonstrate that our proposed method outperforms existing VAE-BO algorithms in various optimization scenarios. Our code will be published at https://github.com/TaicaiChen/PG-LBO.

Seasonal variation of two floral patterns in Clematis ‘Vyvyan Pennell’ and its underlying mechanism

BackgroundFloral patterns are crucial for insect pollination and plant reproduction. Generally, once these patterns are established, they exhibit minimal changes under natural circumstances. However, the Clematis cultivar’ Vyvyan Pennell’, the apetalous lineage in the Ranunculaceae family, produces two distinct types of flowers during different seasons. The regulatory mechanism responsible for this phenomenon remains largely unknown. In this study, we aim to shed light on this floral development with shifting seasonal patterns by conducting extensive morphological, transcriptomic, and hormone metabolic analyses. Our findings are anticipated to contribute valuable insights into the diversity of flowers in the Ranunculaceae family.ResultsThe morphological analysis revealed that the presence of extra petaloid structures in the spring double perianth was a result of the transformation of stamens covered with trichomes during the 5th developmental stage. A de novo reference transcriptome was constructed by comparing buds and organs within double and single perianth from both seasons. A total of 209,056 unigenes were assembled, and 5826 genes were successfully annotated in all six databases. Among the 69,888 differentially expressed genes from the comparative analysis, 48 genes of utmost significance were identified. These critical genes are associated with various aspects of floral development. Interestingly, the A-, B-, and C-class genes exhibited a wider range of expression and were distinct within two seasons. The determination of floral organ identity was attributed to the collaborative functioning of all the three classes genes, aligning with a modified “fading border model”. The phytohormones GA3, salicylic acid, and trans-zeatin riboside may affect the formation of the spring double perianth, whereas GA7 and abscisic acid may affect single flowers in autumn.ConclusionsWe presumed that the varying temperatures between the two seasons served as the primary factor in the alteration of floral patterns, potentially affecting the levels of plant hormones and expressions of organ identity genes. However, a more thorough investigation is necessary to fully comprehend the entire regulatory network. Nonetheless, our study provides some valuable informations for understanding the underlying mechanism of floral pattern alterations in Clematis.

High accuracy size-based droplet separation with pinched flow fractionation

Droplet microfluidics is widely used in biochemical analysis and cell sorting. Conventional droplet-based cell sorting methods typically involve manipulating droplets containing target cells using electric fields or dielectrophoretic forces, which require additional control systems and high voltage. In this study, we investigate the passive structure of pinched flow fractionation to achieve highly accurate separation of droplets with different sizes. The small variation in the sizes of the separated droplets can lead to a reduction in the accuracy of the droplet separation. In our research, we investigate droplet separation through both experiments and simulations, aiming to summarize the principles behind pinched flow separation of droplets. In our experiments, we have successfully separated droplets with diameters smaller than 100 μm as well as those larger than 110 μm. Furthermore, we also take into consideration the impact of sheath flow in the separation process. It is important to note that only an adequate sheath flow rate can ensure that the droplets flow smoothly without interference, maintaining a stable trajectory and thereby ensuring accuracy. The findings of this study can serve as a valuable guide for designing passive droplet separation methods for various types of droplet-based cell sorting systems.

Black-bounces with multiple throats and anti-throats

In this article, we test the possibility of building new black-bounce spacetimes with changes in the area in the context of general relativity in four dimensions. These new metrics can present extra structures, such as anti-throats. We see two regions where the area goes to infinity, and, depending on the model, one of these regions presents curvature singularities. Regular metrics can be extended to negative values of the radial coordinate and have a symmetrical structure, whereas some singular cases cannot be extended and have no symmetrical structure. The energy conditions are analyzed, and, for some cases, at least one of the inequalities in the null energy condition is not respected. We also presented models that satisfied the null energy condition outside the event horizon. The event horizon hides the throats of these models.

Reduced-order models of aeroacoustic sources for sound radiated in twin subsonic jets

We construct reduced-order models of aeroacoustic sources for single and twin subsonic jets ( $M_j=0.9$ , $Re=3600$ ), with the goal of accurately recovering the far-field sound over a wide band of frequencies $St=[0.07,1.0]$ and directivity angles $\phi = [30^{\circ },120^{\circ }]$ within a subdecibel level accuracy. These models are realized via combining spatio-temporally coherent spectral proper orthogonal decomposition (SPOD) modes extracted directly from Lighthill's stress tensor, itself calculated using large-eddy simulation (LES). We consider two sets of twin subsonic jets of diameter $D$ each, with spacings of $0.1D$ and $1D$ , where the jets merge upstream and downstream of breakdown, respectively. The closely spaced twin jet decays the slowest due to reduced turbulent stresses which are, however, more broadband due to early merging. Such jets show strong shielding in the plane of jets, especially at shallow directivity angles where sound levels may drop below that of the single jet. The farther spaced twin jets have dynamics more akin to the constituent single jet with turbulent fluctuations peaking here at $St=0.34$ , but showing very little shielding, with their overall sound pressure level (OASPL) mostly linked to the nature of extra flow structures created during merging. Three-dimensional, energy-ranked, coherent structures for twin jets exhibit rather poor low-rank behaviour, especially at the far-field spectral peak $St=0.14$ . At $St \gtrsim 0.3$ , the SPOD wavepackets show strong visual coherence, resembling Kelvin–Helmholtz instability modes upstream of breakdown, while at the lower frequencies, there is very little spatial coherence with wavepackets peaking downstream of breakdown. Although the leading SPOD modes radiate poorly, reduced-order models using a subset of them, up to $45$ SPOD modes per frequency, show a remarkable match (within $1$ dB) against the LES-predicted sound over $0.1 \lesssim St \lesssim 0.5$ , at all angles investigated. At other frequencies, the closely spaced twin jet shows more error, due to its greater hierarchy of spatio-temporal structures, showing slower convergence at the shallower angles.

Self‐decoupling coupled‐fed patch antennas for 5G multiple‐input multiple‐output applications

AbstractSelf‐decoupling coupled‐fed patch antennas are designed in this letter. The self‐decoupling mechanism is based on the weak‐field region formed by the T‐shaped probe feed and the radiating patch of the antenna element itself. When another identical antenna element is placed in the weak‐field region, high isolation between the two elements can be achieved without adding extra decoupling structures. To validate the decoupling mechanism, a dual‐element antenna array is initially built and an isolation level of better than 30 dB is achieved over the impedance band of 3.3–3.66 GHz with an element spacing of 0.53λ0. Next, a four‐element multiple‐input multiple‐output (MIMO) linear antenna array is presented to further verify the decoupling method and good isolation performance is also obtained, which demonstrates that the proposed designs are good candidates for 5G MIMO applications.

A parametrization of structure-preserving transformations for matrix polynomials

Given a matrix polynomial A(λ) of degree d and the associated vector space of pencils DL(A) described in Mackey et al. [12], we construct a parametrization for the set of left and right transformations that preserve the block structure of such pencils. They form a special class of structure-preserving transformations (SPTs). An SPT in that class maps DL(A) to DL(A˜), where A˜(λ) is a new matrix polynomial that is still of degree d and whose finite and infinite eigenvalues and their partial multiplicities are the same as those of A(λ). Unlike previous work on SPTs, we do not require the leading matrix coefficient of A(λ) to be nonsingular. We show that additional constraints on the parametrization lead to SPTs that also preserve extra structures in A(λ) such as symmetric, alternating, and T-palindromic structures. Our parametrization allows easy construction of SPTs that are low-rank modifications of the identity matrix. The latter transform A(λ) into a matrix polynomial A˜(λ) whose jth matrix coefficient A˜j is a low-rank modification of Aj. We expect such SPTs to be one of the key tools for developing algorithms that reduce a matrix polynomial to Hessenberg form or tridiagonal form in a finite number of steps and without the use of a linearization.

V10-01 A COMPREHENSIVE REVIEW OF NEUROANATOMY, PROSTATE ANATOMY AND PERI-PROSTATIC STRUCTURES

You have accessJournal of UrologyCME1 Apr 2023V10-01 A COMPREHENSIVE REVIEW OF NEUROANATOMY, PROSTATE ANATOMY AND PERI-PROSTATIC STRUCTURES Sneha Parekh and Ashutosh Tewari Sneha ParekhSneha Parekh More articles by this author and Ashutosh TewariAshutosh Tewari More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003328.01AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: We aim to present the most revised anatomy of prostate, surrounding structures and its neuroanatomy in the form a 3D animated video. METHODS: We searched the PubMed database to identify original and review articles that addressed the anatomy of the prostate and relevant surrounding structures, with an emphasis on work published from July 2002 to January 2022. Understanding the findings in literature, we applied this knowledge and created a 3D animation video. RESULTS: Laterally the prostate is surrounded by the Endopelvic fascia, which has Parietal and medially has prostatic fascia. Ventrally prostatic capsule attached to Anterior Fibromuscular Stroma (AFMS), reaches postero-lateral prostate embracing Neurovascular bundle (NVB) medially and becomes pararectal fascia covering the rectum. The detrusor apron is an extension of anterior wall of bladder towards posterior area of pubic bone and contributes to AFMS. The urethral sphincter complex consists of external rhabdosphincter, inner lissosphincter and membranous urethra. Seminal Vesicles(SV) and Vas Deferens (VD) are extra peritoneal tubular structures, located at base of prostate, surrounded by major nerves posterolaterally, associations with Proximal neurovascular plate (PNP). Prostate with surrounding structures is supplied by autonomic and somatic branches originating from lower (T11-L2) and (S2-S4). Nerve fibers from centers coalesce to form pelvic plexus, aka PNP.The autonomic fibers from PNP are distributed into NVB and ANP (Accessory Neural Pathway) in a spray like pattern, with 60% of fibers on postero-lateral and 40% on antero-lateral prostate.DVC is composed of nerve fibers, dorsal veins and prostatic arteries. The puboprostatic ligamentous complex comprises of puboprostatic ligaments, arcus tendineus, and puboperinealis muscle. The puboprostatic ligaments are dense pyramid-shaped medial portions of distal endopelvic fascia. The puboperinealis is a paired muscle that originates from pubis, flanks prostatic-urethral junction, terminates at perineal body. CONCLUSIONS: Prostate is a dense fibromuscular gland, situated in the true pelvis surrounded by a compact multi-layered fascia with intermingling nerves and vessels.The nerves from the lumbar and sacral roots along with somatic supply form the pelvic plexus, further giving the prostatic neural hammock. This forms the basis of nerve sparing and its grades. Puboprostatic ligamentous complex along with peri-prostatic fascia and detrusor apron support the prostate and has a role in erectile and continence. Source of Funding: None © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e926 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Sneha Parekh More articles by this author Ashutosh Tewari More articles by this author Expand All Advertisement PDF downloadLoading ...

2-D Photo-Thermal Distribution and Structures of Flip-Chip Mini Light-Emitting Diodes by Microscopic Hyperspectral Imaging

Given the growing interest in micro-scale thermal management of mini- and micro-light-emitting diodes (LEDs), it’s crucial to develop an effective two-dimensional (2D) junction temperature measurement method. In this paper, the microscopic hyperspectral imaging (μ-HSI) technique has been proposed to probe the 2D photo-thermal distribution of the flip-chip mini-LEDs. Running on a two-axis rotating platform, μ-HSI is able to directly focus on the epitaxial layer surface (episurface) and lateral side of the LED chips to acquire their 2D spectral distributions. Subsequently, the full width at half maximum matrix was extracted to deduce the 2D junction temperature distributions. As a result, the location and temperature distribution of the active layer, i.e., PN junction, can be determined accurately. The mean temperature of the episurface approximately matches that of the active layer. The Raman shift method was applied to verify the accuracy of the μ-HSI technique. In addition, the extra fine structures as well as temperature distributions of the interface between the episurface and sapphire or electrodes are distinguished and analyzed by this technique. This work offers an effective tool for the quality improvement and thermal management of mini-LEDs.

Anisotropic photon emission from gluon fusion and splitting in a strong magnetic background: The two-gluon one-photon vertex

Having in mind the pre-equilibrium stage in peripheral heavy-ion collisions as a possible scenario for the production of electromagnetic radiation, we compute the two-gluon one-photon vertex in the presence of an intense magnetic field at one-loop order. The quarks in the loop are taken such that two of them occupy the lowest Landau level, with the third one occupying the first excited Landau level. When the field strength is the largest of the energy (squared) scales, the tensor basis describing this vertex corresponds to two of the three-vector particles polarized in the longitudinal direction whereas the third one is polarized in the transverse direction. However, when the photon energy is of the same order as or larger than the field strength, the explicit one-loop computation contains extra tensor structures that spoil the properties of the basis compared with the case when the field strength is the largest of the energy scales, which signals that the calculation is incomplete. Nevertheless, by projecting the result onto the would-be basis, we show that the squared amplitude for processes involving two gluons and one photon exhibits the expected properties such as a preferred in-plane photon emission and a slightly decreasing strength for an increasing magnetic-field strength. We comment on possible venues to improve the one-loop calculation that include accounting for progressive occupation of the three quarks of the lowest and first-excited Landau levels such that, still working in the large field limit, a more complete description can be achieved when the photon energy increases.

Quantum oscillations of Kondo screening phases in strong magnetic fields

We generalize the iterative diagonalization procedure adopted in method of numerical renormalization group to analyze the Kondo effect in strong magnetic fields, where the density of states for itinerary electrons at the chemical potential varies discontinuously as the magnetic field changes. We first examine phases of many-body ground states in the presence of single impurity. By investigating change of $z$-component of total spin, $\Delta S_z$, and spin-spin correlation between the impurity and conduction electrons, we find that there are three states competing for the ground state when Zeeman splitting is present. One of the states is doublet in which the impurity spin is unscreened. The other two states are Kondo screening states with $\Delta S_z=1/2$ and $\Delta S_z=1$, in which the impurity spin is partially screened and completely screened respectively. For Kondo systems with two-impurities in strong magnetic fields, we find that the interplay between the Kondo screening effect, RKKY interaction, and quantum oscillations due to Landau levels determines the ground state of the system. Combination of these three factors results in different screening scenarios for different phases in which spins of two impurities can form spin-0 or spin-1 states, while impurity spins in these phases can be either screened, partially screened, or unscreened by conduction electrons. The emergence of the ground state from these competing states oscillates with the change of magnetic field, chemical potential or inter-impurity distance. This leads to quantum oscillations in magnetization and conductivity. In particular, we find extra peak structures in longitudinal conductivity that reflect changes of Kondo screening phases and are important features to be observed in experiments. Our results provide a complete characterization of phases for Kondo effect in strong magnetic fields.

Closely arranged self‐decoupled MIMO antenna group using orthogonal mode and pattern diversity for 5G mobile terminals

In this article, a novel self-decoupling method for closely arranged multi-unit antenna array design is proposed. The orthogonal mode and the pattern diversity are adopted to weaken the electromagnetic coupling between the multi-antenna elements. To verify the proposed self-decoupling concept, a closely arranged 4-port antenna group consisting of dual antenna pairs is designed. One of the antenna pairs is composed of overlapping loop antenna and monopole, and the other antenna pair shares a radiator, which are arranged on the upper and lower sides of the metal ground respectively. The proposed 4-port antenna group exhibits good isolation and complementary patterns without adding any extra decoupling structures. Based on the proposed self-decoupled 4-port antenna group, a 16 × 16 multiple-input multiple-output (MIMO) antenna array is constructed. The simulated and measured results show that the proposed 16 × 16 MIMO array has good antenna performance, such as isolation better than 15 dB, efficiency higher than 51% and channel capacity about 73 bps/Hz with 20 dB SNR. The proposed design concept is a great choice for highly integrated multi-antenna array and 5G mobile terminal.

A Wideband Low-RCS Circularly Polarized Reconfigurable C-Shaped Antenna Array Based on Liquid Metal

A wideband low radar cross-section (RCS) circularly polarized (CP) reconfigurable patch antenna array based on liquid metal (LM) has been proposed in this article. The array was formed by <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4\,{\times }\,4$ </tex-math></inline-formula> CP C-shaped antenna elements fed with a sequential feeding network. The antenna element was designed with a pair of narrow slots, and a microchannel adhered to the top metal layer. The CP reconfiguration depends on the tuning of the slots by moving the LM in the channel. The patch antenna array can obtain good CP radiation and low RCS features without any extra RCS reduction structures other than the array elements. RCS reduction (RCSR) can be realized by <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$180^{\circ }\,{\pm }\,37^{\circ }$ </tex-math></inline-formula> reflection phase variations between two different antenna elements under normal incidence for both <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$x$ </tex-math></inline-formula> - and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$y$ </tex-math></inline-formula> -polarizations. The antenna prototype has been fabricated and measured. The measured results show good agreement with simulated results.

Information-Theoretic Odometry Learning

In this paper, we propose a unified information theoretic framework for learning-motivated methods aimed at odometry estimation, a crucial component of many robotics and vision tasks such as navigation and virtual reality where relative camera poses are required in real time. We formulate this problem as optimizing a variational information bottleneck objective function, which eliminates pose-irrelevant information from the latent representation. The proposed framework provides an elegant tool for performance evaluation and understanding in information-theoretic language. Specifically, we bound the generalization errors of the deep information bottleneck framework and the predictability of the latent representation. These provide not only a performance guarantee but also practical guidance for model design, sample collection, and sensor selection. Furthermore, the stochastic latent representation provides a natural uncertainty measure without the needs for extra structures or computations. Experiments on two well-known odometry datasets demonstrate the effectiveness of our method.

STM/STS study of the local density of states in Cu doped Fe(Se,Te) superconductors

The scanning tunnel microscopy/scanning tunnel spectroscopy (STM/STS) measurements of the local quasiparticle density of states (LDOS) in Cu x -Fe1.01-x Se0.4Te0.6 (x = 0.01-0.03) superconductors were carried out. Critical temperatures Tc decrease with increasing Cu-impurity doping level x. STM images show clear regular square arrangements of spots with the lattice spacing ~ 0.38 nm as well as the randomly distributed large spots, which are most possibly due to excess Fe atoms. While the STM image resembles that of non-doped Fe(Se,Te), the LDOS map shows various extra spot structures with bright (with higher magnitudes of dI/dV) and dark (with lower magnitudes of dI/dV) regions. With increasing x, the number of such spots grows proportionally, indicating that these spots most probably correspond to the dopant Cu atoms.

Nanofocusing performance of plasmonic probes based on gradient permittivity materials

Probe is the core component of an optical scanning probe microscope such as scattering-type scanning near-field optical microscopy (s-SNOM). Its ability of concentrating and localizing light determines the detection sensitivity of nanoscale spectroscopy. In this paper, a novel plasmonic probe made of a gradient permittivity material (GPM) is proposed and its nanofocusing performance is studied theoretically and numerically. Compared with conventional plasmonic probes, this probe has at least two outstanding advantages: first, it does not need extra structures for surface plasmon polaritons excitation or localized surface plasmon resonance, simplifying the probe system; second, the inherent nanofocusing effects of the conical probe structure can be further reinforced dramatically by designing the distribution of the probe permittivity. As a result, the strong near-field enhancement and localization at the tip apex improve both spectral sensitivity and spatial resolution of a s-SNOM. We also numerically demonstrate that a GPM probe as well as its enhanced nanofocusing effects can be realized by conventional semiconductor materials with designed doping distributions. The proposed novel plasmonic probe promises to facilitate subsequent nanoscale spectroscopy applications.