Layered Media Research Articles

Highly reliable and ultra-wideband metamaterial absorber based on graphene-assembled films for extremes

Metamaterial absorbers have demonstrated significant potential in mitigating electromagnetic pollution, yet there is a dearth of research on absorbers that function effectively in extreme environments. In this work, a highly reliable and ultra-wideband metamaterial absorber based on graphene-assembled films (GAFs) is proposed. The presented absorber consists of four-layer structures, including a high-resistance GAF pattern layer, a polyimide medium layer, an air layer, and a low-resistance GAF layer. The periodic ring structure made of high-resistance GAF by screen printing with a sheet resistance of 57 Ω/sq exhibits excellent characteristics of wideband absorption and broad incidence angle absorption. The GAF absorber demonstrates a measured absorption efficiency exceeding 90 %, covering 4.24–17.90 GHz, and has a relative bandwidth of 123.4 %, which exhibits good stability when electromagnetic waves are incident at 0–30°. More importantly, the GAF absorber maintains excellent performance in various extreme conditions, including acid, alkali, salt spray, high-humidity, high-temperature, and low-temperature environments. Therefore, the GAF absorber demonstrates consistent reliability and stability under extreme conditions, which is significant for electromagnetic protection under extremes.

A novel tool for seismic response analysis of tunnel in multilayered media based on kinematic earthquake source

Earthquake damage of underground structure indicates that the seismic response of tunnels is affected by the earthquake source, propagation medium, and local tunnel-surrounding rock system. Current research on the seismic response of tunnels primarily focuses on local tunnel systems, posing a challenge in comprehensively assessing the impact of earthquakes on tunnel group. This study introduces a theoretical seismological approach for the seismic response analysis of tunnels and presents a novel methodology for assessing the response. The proposed approach uses a kinematic seismic source as the earthquake source, assuming the geological strata as a layered medium and a tunnel as a point within a semi-infinite space. The wavenumber-integral method was used to solve for the seismic wave field and strain. To reflect the followability of underground structure to the surrounding rock deformation, we improved it and derived an analytical formula for the strain. The 2022 Menyuan earthquake was considered as a case study; the seismic damage to tunnels along the Lan-Xin Railway was analyzed using the proposed approach. The results confirm that there is a strong correlation between tunnel damage and free-field strain induced by earthquakes. The theoretical influence range of earthquake on tunnel was investigated using the diameter deformation ratio of the tunnel as an indicator. For tunnels embedded in a grade III rock mass, the theoretical range was approximately 7.0 km on both sides of the fault. For tunnels embedded in a grade V rock mass, the theoretical range can reach up to 25.9 km. The results also revealed that tunnels on the hanging-wall side of the fault had a more significant impact than those on the foot-wall side, although their affected areas were smaller.

Abstract Tu019: Single-Cell RNA Sequencing Identifies IFNICs as a Cellular Target for Mitigating the Progression of Abdominal Aortic Aneurysm and Rupture Risk

Introduction: Abdominal aortic aneurysm (AAA) represents a life-threatening condition characterized by medial layer degeneration of the abdominal aorta. Nevertheless, knowledge regarding changes in regulators associated with aortic status remains incomplete. A thorough understanding of cell types and signaling pathways involved in the development and progression of AAAs is essential for the development of medical therapy. Methods and Results: We harvested specimens of the abdominal aorta with different pathological features in Angiotensin II (AngII)-infused ApoE -/- mice, conducted scRNA-seq, identified a unique population of interferon-inducible monocytes/macrophages (IFNICs), which were amply found in the abdominal aortic aneurysms (AAAs). Gene set variation analysis (GSVA) revealed that activation of the cytosolic DNA sensing cGAS-STING and JAK-STAT pathways promoted the secretion of type I interferons in monocytes/macrophages and differentiated them into IFNICs. We generated myeloid cell-specific deletion of Sting1 ( Lyz2 -Cre +/- ; Sting1 flox/flox ) mice and performed bone marrow transplantation and found that myeloid cell-specific deletion of Sting1 or Ifnar1 significantly reduced the incidence of AAA, aortic rupture rate and diameter of the abdominal aorta. Mechanistically, the activated pyroptosis- and inflammation-related signaling pathways, regulated by IRF7 in IFNICs, play critical roles in the developing AAAs. Conclusion: IFNICs is a unique monocyte/macrophage subset implicated in the development of AAAs and aortic rupture.

The role of 6-phosphogluconate dehydrogenase in vascular smooth muscle cell phenotypic switching and angioplasty-induced intimal hyperplasia

BackgroundRestenosis poses a significant challenge for individuals afflicted with peripheral artery diseases, often leading to considerable morbidity and necessitating repeated interventions. The primary culprit behind the pathogenesis of restenosis is intimal hyperplasia (IH), in which the hyperproliferative and migratory vascular smooth muscle cell (VSMC) accumulate excessively in the tunica intima. 6-Phosphogluconate dehydrogenase (6PGD), sometimes referred to as PGD, is one of the critical enzymes in pentose phosphate pathway (PPP). In this study, we sought to probe whether 6PGD is aberrantly regulated in IH and contributes to VSMC phenotypic switching. MethodsWe used clinical specimens of diseased human coronary arteries with IH lesions and observed robust upregulation of 6PGD at protein level in both the medial and intimal layers in comparison with healthy arterial segments. Results6PGD activity and protein expression were profoundly stimulated upon platelet-derived growth factor-induced VSMC phenotypic switching. Using gain-of-function (dCas9-mediated transcriptional activation) and loss-of-function (small interfering RNA-mediated) silencing, we were able to demonstrate the pathogenic role of 6PGD in driving VSMC hyperproliferation, migration, dedifferentiation, and inflammation. Finally, we conducted a rat model of balloon angioplasty in the common carotid artery, with Pluronic hydrogel-assisted perivascular delivery of Physcion, a selective 6PGD inhibitor with poor systemic bioavailability, and observed effective mitigation of IH. ConclusionsWe contend that aberrant 6PGD expression and activity—indicative of a metabolic shift toward pentose phosphate pathway—could serve as a new disease-driving mechanism and, hence, an actionable target for the development of effective new therapies for IH and restenosis after endovascular interventions.

Alternative Implementation of EM Propagation for 3-D Layered Lossy Media by SMM Method

Alternative Implementation of EM Propagation for 3-D Layered Lossy Media by SMM Method

Acoustic response of patchy-saturated porous media: Coupling Biot's poroelasticity equations for mono- and biphasic pore fluids.

Patchy saturation is a term used in the seismic prospecting literature to describe the state of a geological formation in which two immiscible pore fluids prevail in mesoscopic-scale clusters. If the pore fluids have contrasting compressibilities, wave-induced fluid pressure diffusion (FPD) processes may induce significant attenuation and velocity dispersion on seismic waves. Biot's monophasic poroelasticity theory is widely used to model the seismic response of rocks containing binary patches of two immiscible pore fluids. Even though effective fluid approximations may help to represent more realistic partially saturated patches using Biot's monophasic equations, the so inferred dissipation may not be representative of actual biphasic FPD phenomena. In this work, Biot's equations for mono- and biphasic fluids are combined to model FPD processes in porous media, comprising fully and partially saturated patches. An analytical solution for one-dimensional layered patchy-saturated media is presented which permits to explain some, as of yet enigmatic, experimentally observed characteristics such as increased seismic attenuation and stiffening effects occurring at low saturations. The results show that the existence of an additional diffusive wave mode within partially saturated patches may render conventional binary and effective fluid approaches incorrect and error prone.

Reversal of heavy arterial calcification in a rat model of chronic kidney disease using targeted ethylene diamine tetraacetic acid-loaded albumin nanoparticles.

Elastin degradation and severe calcification in the medial layer of the vessel wall, known as medial arterial calcification (MAC), is typical in the aging population and patients with metabolic disorders, such as diabetes and chronic kidney disease (CKD). We have previously reported that ethylene diamine tetraacetic acid (EDTA) delivery to the site of calcification can be achieved by tagging nanoparticles with an elastin antibody that recognizes explicitly damaged elastin, and such systemic therapy can remove focal calcium deposits from the calcified arteries in CKD rodent model. The current study aims to test whether heavy calcification seen throughout arterial tree and kidneys in CKD can be reversed with nanoparticle therapy. Thirty healthy male Sprague-Dawley rats weighing approximately 300 g, were placed on an adenine diet for 21 non-consecutive days to induce kidney failure, followed by daily vitamin D3 (VitD3) injections for 4 sequential days to cause severe calcification throughout the cardiovascular system and kidneys. DiR-dye loaded and elastin antibody conjugated albumin nanoparticles were used to confirm the targeting of nanoparticles to the calcification area. The rats were divided into two groups for targeted removal of calcification starting at day 7 of the last doses of VitD3. The experimental group received biweekly IV injections of anti-elastin antibody conjugated EDTA loaded human serum albumin nanoparticles (EDTA-HSA-El-Ab NPs), while the sham controls received blank nanoparticles (Blank-HSA-El-Ab NPs) (5 injections in total). Micro-computed tomography (microCT) was used to analyze the extent of calcification. Reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemistry studies were performed for osteogenic markers, including bone morphogenic protein 2 (BMP2), runt-related transcription factor 2 (RUNX2), and tissue non-specific alkaline phosphatase (TNAP). For comparison, aortic ring organ cultures from healthy rats were treated with high phosphate to induce calcification in vitro, and then they were treated with EDTA. Human calcified femoral arteries were also treated ex vivo with EDTA-HSA-EL-Ab NPs to test if nanoparticles remove heavy calcification. EDTA-loaded nanoparticles that specifically target degraded elastin reversed existing heavy mineral deposits in arteries, as per elemental calcium analysis (124.161±34.410 µg Ca per mg of the dry aorta in Blank-HSA-El-Ab NPs vs. 100.520±19.131 µg in EDTA-HSA-El-Ab NPs group, P=0.04) and microCT (object volume, 129.001±37.785 vs. 29.815±24.169 mm3, P=0.0005). The reversal of aortic calcification was accompanied by a significant reduction of bone-associated mRNA expression of BMP2 and RUNX2 (P=0.01). Immunohistochemistry studies corroborated RT-PCR results, showing a reduction of BMP2 and RUNX2 stains in the vessel wall. The rat aortic ring culture study also showed similar results, where osteogenic genes (BMP2, RUNX2) and proteins (BMP2, RUNX2, TNAP) were suppressed upon reversal of calcification with EDTA (P=0.001). We also show ex vivo reversal of human femoral artery calcification by microCT (calcium intensity: untreated, 57.721±28.551 vs. day 6 of treatment, 5.441±3.615, P=0.01) by EDTA nanoparticle therapy. This is the first study showing the removal of calcium from heavily calcified arteries by using intravenous targeted EDTA therapy. Such therapy also reversed vascular smooth muscle cell osteoblastic transition and apoptosis in the arterial tissue, thereby potentially creating an environment for suitable tissue repair.

The Buerger’s rabbit model: a closer step to unravelling thromboangiitis obliterans?

ObjectiveThromboangiitis obliterans (TAO) remains clinical challenging due to its rarity and underwhelming management outcomes. This study aimed to describe a novel TAO rabbit model that demonstrates a closer resemblance to TAO.MethodsThirty-six New Zealand rabbits underwent the surgical implantation of calibrated gelatin sponge particles (CGSPs) into their right femoral artery. The CGSPs were soaked in different solutions to simulate different types of thrombi: normal (NT; normal saline); inflammatory TAO thrombus (TAO; dimethylsulfoxide [DMSO]), and DMSO with methotrexate (MTX). All groups underwent clinical assessment, digital subtraction angiography (DSA) and histopathological analysis at time points day 0 (immediate), week 1 (acute), week 2 (subacute), and week 4 (chronic).ResultsThe TAO rabbit presented with signs of ischemia of the right digit at week 4. On DSA, the TAO rabbits exhibited formation of corkscrew collaterals starting week 1. On H&E staining, gradual CGSP degradation was observed along with increased red blood cell aggregation and inflammatory cells migration in week 1. On week 2, disorganization of the tunica media layer and vascular smooth muscle cell (VSMC) proliferation was observed. In the TAO rabbit, migrated VSMCs, inflammatory cells, and extracellular matrix with collagen-like substances gradually occluded the lumen. On week 4, the arterial lumen of the TAO rabbit was filled with relatively-organized VSMC and endothelial cell clusters with less inflammatory cells. Neorevascularization was found in the MTX-treated group.ConclusionThe novel TAO rabbit model shows a closer resemblance to human TAO clinically, radiographically, and histopathologically. Histological analysis of the IT progression in the TAO model suggests that it is of VSMC origin.

Multifunctional PDMS/Schiff base/SiO2 gel assisted fabrication of printed, stretchable and straight copper conductors

Printable, stretchable, and highly conductive metal conductors have emerged as potentially promising interconnects in the field of soft electronics. However, current techniques relying on geometric engineering have been criticized for complicated fabrication process and defective geometric structure. Here, we report a printed, straight, and omnidirectionally stretchable copper conductor, which is facilely fabricated on a flat substrate without requiring prestretching, assisted by a multifunctional gel medium layer. The PSS gel, composited by polydimethylsiloxane, Schiff base and fumed SiO2, offers a unique combination of stretchability, printability, and moldability. Additionally, this gel enables the reduction of silver ions directly on its surface by partially bonded crosslinker molecules. The fully exposed catalyst exhibits excellent activity in catalyzing electroless copper deposition reaction, on which high-quality copper coating is facilely achieved. The produced copper patterns exhibit high conductivity (4.93 × 107 S m−1) and excellent stretchability with fracture strains of ∼ 191 % and ∼ 135 % for the uni- and omni-directionally stretchable patterns respectively, which are superior to the majority of stretchable metals in published literature. The stretchable wrinkles derive form the gel medium layer molded by templates, realizing straight metal lines on flat substrate. This process combines the advantages of traditional in-plane and out-of-plane strategies, demonstrating great potential in practical application.

Absorption of ultrashort laser pulses in medium with account for propagation effects

The absorption of ultrashort laser pulses in an optically dense medium is theoretically studied based on the total absorption coefficient over the entire duration of the pulse, taking into account the effects of propagation and reflection of pulse from vacuum/medium interface. The approach is the generalization of our previous work (available at: www.nobelprize.org/prizes/physics/2023/summary), which traced a ‘bridge’ between the micro- and macro-description of radiation processes in a medium induced by electromagnetic pulses of arbitrary duration. The expression for the total absorption coefficient is obtained in terms the complex refractive index of the medium. Various limits of this expression are considered. Numerical calculations of the dependence of the total absorption coefficient on the parameters of the laser pulses and the thickness of the medium layer were carried out and the results obtained were discussed.

Prediction of the dynamic pressure drop of filter media loaded with water mists based on the deposited droplet mass distributions and pore network model

Predicting the pressure drop of a filter is necessary, especially regarding the jump in the dynamic pressure drop of a filter without pre-filters when clogged by rain or fog droplets. However, the efficient prediction method for the pressure drop in cylinder filters loading with water mists in the pore network faces limitations due to the high requirements for microscopic images of materials and the need to consider for the increasing holding droplet capacity of filters. In this study, a systematic method that takes into account the distributions of the deposited droplet mass within the water-absorbed filter medium layers in the pore network model (PNM) was developed. The pore geometry and distributions were determined from 2D microstructure images, and the dynamic deposited droplet mass and water-absorbing capacity of fibers were combined with the changing saturation to optimize the PNM for calculating the dynamic pressure drop of the filter media. Specifically, the empirical equation of the self-defined equivalent single fiber filtration efficiency (ESFFE) describes the relationship between the changing single fiber filtration efficiency and the deposited droplet mass. The optimized PNM is suitable for predicting the behavior of bibulous wood cellulose fiber filter media. The dynamic pressure drop shows a slight increase before surging, following the typical “channel and jump” model. Although the calculations deviate slightly from the experimental results with 25 % deviations, this systematic method effectively predict the jump in pressure drop of the tested filter medium. Therefore, this systematic method for predicting pressure drop of filters holds promise in anticipating unsafe pressure drop jumps in filters installed in coastal areas.

Resolving full-wave through-wall transmission effects in multi-static synthetic aperture radar

Through-wall synthetic aperture radar (SAR) imaging is of significant interest for security purposes, in particular when using multi-static SAR systems consisting of multiple distributed radar transmitters and receivers to improve resolution and the ability to recognise objects. Yet there is a significant challenge in forming focused, useful images due to multiple scattering effects through walls, whereas standard SAR imaging has an inherent single scattering assumption. This may be exacerbated with multi-static collections, since different scattering events will be observed from each angle and the data may not coherently combine well in a naive manner. To overcome this, we propose an image formation method which resolves full-wave effects through an approximately known wall or other arbitrary obstacle, which itself has some unknown ‘nuisance’ parameters that are determined as part of the reconstruction to provide well focused images. The method is more flexible and realistic than existing methods which treat a single wall as a flat layered medium, whilst being significantly computationally cheaper than full-wave methods, strongly motivated by practical considerations for through-wall SAR.

Analytical and numerical examinations on the stability investigation of Casson nanofluid flow in a permeable layer controlled by vertical throughflow

Purpose The purpose of the study is to analytically as well as numerically investigate the weight of throughflow on the onset of Casson nanofluid layer in a permeable matrix. This study examines both the marginal and over stable kind of convective movement in the system. Design/methodology/approach A double-phase model is used for Casson nanofluid, which integrates the impacts of thermophoresis and Brownian wave, whereas for flow in the porous matrix the altered Darcy model is occupied under the statement that nanoparticle flux is disappear on the boundaries. The resultant eigenvalue problem is resolved analytically as well as numerically with the help of Galerkin process with the Casson nanofluid Rayleigh–Darcy number as the eigenvalue. Findings The findings revealed that the throughflow factor postpones the arrival of convective flow and reduces the extent of convective cells, whereas the Casson factor, the Casson nanoparticle Rayleigh–Darcy number and the reformed diffusivity ratio promote convective motion and also decrease the extent of convective cells. Originality/value Controlling the convective movement in heat transfer systems that generate high heat flux is a real mechanical challenge. The proposed framework proved that the use of throughflow is one of the most important ways to control the convective movement in Casson nanofluid. To the best of the authors’ knowledge, no inspection has been established in the literature that studies the outcome of throughflow on the Casson nanofluid convective flow in a porous medium layer. However, the convective flow of Casson nanofluid finds many applications in improving heat transmission and energy efficiency in a range of thermal systems, such as the cooling of heat-generating elements in electronic devices, heat exchangers, pharmaceutical practices and hybrid-powered engines, where throughflow can play a significant role in controlling the convective motion.

Investigations of Laser-Assisted Renal Denervation for Treatment of Resistant Hypertension.

Renal denervation (RDN) is an emerging surgical treatment for resistant hypertension. However, the current RDN using radiofrequency can cause undesirable thermal damage to the medial and luminal layers due to direct contact between the arterial lumen and energy source. The aim of this study is to evaluate the feasibility of the new laser-assisted RDN by exploring the potential treatment conditions. For ex vivo testing, six different treatment conditions (10 and 20 W applied for delivery of 300, 450, and 600 J) were tested on the porcine liver and renal artery (RA) by using a continuous wave 1064 nm laser wavelength. The ablated area in the liver tissue was measured to estimate the extent of the coagulated area. Histological evaluation was performed on the treated RA tissues to confirm the extent of thermal nerve damage. The ablated depth, length, and area in the liver tissue increased with laser power and total energy. According to the histological results, 20 W groups yielded more significant damage to the RA nerves than 10 W groups at the total energy of 300 J (0.0 ± 0.0 mm for 10 W vs. 2.9 ± 1.0 mm for 20 W), 450 J (1.9 ± 0.6 mm for 10 W vs. 6.8 ± 1.5 mm for 20 W), and 600 J (2.9 ± 0.4 mm for 10 W vs. 7.3 ± 0.8 mm for 20 W). The treated RA exhibited insignificant medial injury in depth (medial thinning ≤ 25%), and no difference in the medial thinning was found among the six groups (p = 0.4). The current study demonstrated that the 1064 nm laser at 20 W with delivery of 450 J could effectively damage the RA nerves with no or minimal injury to the surrounding tissue. The proposed laser-assisted RDN may enhance physiological effects with insignificant complications in in vivo situations. Further in vivo studies will be conducted to validate the current findings by evaluating the extent of blood pressure reduction and norepinephrine changes after the laser-assisted RDN on a large animal model.

Universal and nonuniversal statistics of transmission in thin random layered media

The statistics of transmission through random 1D media are generally presumed to be universal and to depend only upon a single dimensionless parameter-the ratio of the sample length and the mean free path, s = L / ℓ . Here we show in numerical simulations and optical measurements of random binary systems, and most prominently in systems for which s<1, that the statistics of the logarithm of transmission, ln ⁡ T , are universal for transmission near the upper cutoff of unity and depend distinctively upon the reflectivity of the layer interfaces and their number near a lower cutoff. The universal segment of the probability distribution function of the logarithm of transmission, P ( ln ⁡ T ) is manifested with as few as three binary layers. For a given value of s, P ( ln ⁡ T ) evolves towards a universal distribution as the number of layers increases. Optical measurements in stacks of 5 and 20 glass coverslips exhibit statistics at low and moderate values of transmission that are close to those found in simulations for 1D layered media, while differences appear at higher transmission where the transmission time in the medium is longer and the wave explores the transverse nonuniformity of the sample.

Near-surface velocity inversion and modeling method based on surface waves in petroleum exploration: a case study from Qaidam Basin, China

Surface waves are widely used in the study of underground structures at various scales because of their dispersion characteristics in layered media. Whether in natural seismology or engineering seismology, surface wave analysis methods have matured and developed for their respective fields. However, in oil and gas exploration, many data processors still tend to consider surface waves as noise that needs to be removed. To make more people pay attention to the application of surface waves and widely utilize surface waves carrying the near surface information in oil and gas exploration, this paper takes the data processing of LH site in Qinghai, China as an example to apply surface wave analysis methods to oil and gas exploration. We first preprocess and perform dispersion imaging method on the seismic record in the LH site to obtain frequency-phase velocity spectrum with good resolution and signal-to-noise ratio. Then, utilizing clustering algorithms, it automatically identifies and picks dispersion curves. Finally, through a simultaneous inversion algorithm of velocity and thickness, it inverts the dispersion curves and obtain S-wave velocity profiles in the depth range of 0–200 m. The near surface is divided into four zones based on velocity ranges and depth ranges. Additionally, we apply the surface waves inversion results as constraints to first-arrival tomography and obtain objectively accurate P-wave velocity profiles and Poisson’s ratio profiles. The results indicate that by applying surface wave analysis methods, the near surface velocity information carried by surface waves can be extracted, providing near surface velocity models for static correction and migration. At the same time, compared with the surface wave application in engineering seismology, the scale of oil and gas exploration is larger, so that the data processing of surface waves is particularly important, otherwise it will affect the picking of the dispersion curve and inversion.

Design of inherently polarized nanofiber-based membranes for superior filtration performance

As airborne particulate matter (PM) such as pathogens and ultrafine dust threaten the human health, air quality control technologies are becoming increasingly important. Herein, poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) nanofibers with various fiber diameters and pore size distributions were prepared using various compositions of volatile (acetone) and less volatile N,N-dimethylformamide (DMF) solvent mixtures to design the optimum filtration media. Morphologies and molecular configurations were examined thoroughly with respect to the filtration performance. Among the various solvent compositions, the specimen prepared with the lowest DMF content (denoted as ePVdF-HFP55) showed the best filtration performance, with a filtration efficiency of 99.95% and a pressure drop of 29.0 mmH2O. The quality factor (QF) of ePVdF-HFP55 (0.0266 Pa−1) is superior to that achieved in electrospun nanofibrous media in previous works. In addition, the QF was further improved to 0.0276 Pa−1, with a remarkably reduced resistance of 14.45 mmH2O achieved by employing the layered nanofiber media with a PVdF-HFP top layer. Our work demonstrates that optimization of the inherently polarized nanofiber synthesis is a fruitful pathway to enhancing the filtration performance of air filter media.

Microstructure and digestive behaviors of inner, middle, and outer layers of pork during heating

To investigate the effects of heat treatment on the microstructure and digestive behaviors of pork, meat samples were subjected to a 100 °C water bath for 26 min. The inner, medium, and outer layers were assigned and analyzed according to the temperature gradient. Compared to the raw samples, significant changes were observed in the microscopic structure of pork. As the temperature increased, the myofibrillar structure of pork underwent increasingly severe damage and the moisture content decreased significantly (P < 0.05). Moreover, differential peptides were identified in digested products of the inner, middle, and outer layers of cooked pork, which are mainly derived from the structural proteins of pork. The outcomes of molecular docking indicated that a greater number of hydrogen bonds were formed between myosin and the digestive enzyme in the inner layer, rather than other parts, contributing to the transformation of digestive behaviors.

WDFF-Net: Weighted Dual-Branch Feature Fusion Network for Polyp Segmentation With Object-Aware Attention Mechanism.

Colon polyps in colonoscopy images exhibit significant differences in color, size, shape, appearance, and location, posing significant challenges to accurate polyp segmentation. In this paper, a Weighted Dual-branch Feature Fusion Network is proposed for Polyp Segmentation, named WDFF-Net, which adopts HarDNet68 as the backbone network. First, a dual-branch feature fusion network architecture is constructed, which includes a shared feature extractor and two feature fusion branches, i.e. Progressive Feature Fusion (PFF) branch and Scale-aware Feature Fusion (SFF) branch. The branches fuse the deep features of multiple layers for different purposes and with different fusion ways. The PFF branch is to address the under-segmentation or over-segmentation problems of flat polyps with low-edge contrast by iteratively fusing the features from low, medium, and high layers. The SFF branch is to tackle the the problem of drastic variations in polyp size and shape, especially the missed segmentation problem for small polyps. These two branches are complementary and play different roles, in improving segmentation accuracy. Second, an Object-aware Attention Mechanism (OAM) is proposed to enhance the features of the target regions and suppress those of the background regions, to interfere with the segmentation performance. Third, a weighted dual-branch the segmentation loss function is specifically designed, which dynamically assigns the weight factors of the loss functions for two branches to optimize their collaborative training. Experimental results on five public colon polyp datasets demonstrate that, the proposed WDFF-Net can achieve a superior segmentation performance with lower model complexity and faster inference speed, while maintaining good generalization ability.

Mönckeberg calcification in a temporal artery

Mönckeberg’s calcification is a disease of low prevalence and unknown etiology that causes calcification of the middle layer of medium and small arteries. It usually presents with a clinical picture similar to giant cell arteritis, so a differential diagnosis with similar entities should be made. The diagnosis is anatomopathological, and there is no treatment that has shown significant results. Herein, we present the case of a 74-year-old male patient with recurrent syncope and chest pain, in whom giant cell arteritis was suspected and a temporal artery biopsy was taken with the incidental finding of calcification of Mönckeberg’s media. Key words: Calcification, Arteritis, Giant cell, Mönckeberg