Opposite Side Research Articles

Multidimensional Analysis of Physiological Entropy during Self-Paced Marathon Running.

The pacing of a marathon is arguably the most challenging aspect for runners, particularly in avoiding a sudden decline in speed, or what is colloquially termed a "wall", occurring at approximately the 30 km mark. To gain further insight into the potential for optimizing self-paced marathon performance through the coding of comprehensive physiological data, this study investigates the complex physiological responses and pacing strategies during a marathon, with a focus on the application of Shannon entropy and principal component analysis (PCA) to quantify the variability and unpredictability of key cardiorespiratory measures. Nine recreational marathon runners were monitored throughout the marathon race, with continuous measurements of oxygen uptake (V˙O2), carbon dioxide output (V˙CO2), tidal volume (Vt), heart rate, respiratory frequency (Rf), and running speed. The PCA revealed that the entropy variance of V˙O2, V˙CO2, and Vt were captured along the F1 axis, while cadence and heart rate variances were primarily captured along the F2 axis. Notably, when distance and physiological responses were projected simultaneously on the PCA correlation circle, the first 26 km of the race were positioned on the same side of the F1 axis as the metabolic responses, whereas the final kilometers were distributed on the opposite side, indicating a shift in physiological state as fatigue set in. The separation of heart rate and cadence entropy variances from the metabolic parameters suggests that these responses are independent of distance, contrasting with the linear increase in heart rate and decrease in cadence typically observed. Additionally, Agglomerative Hierarchical Clustering further categorized runners' physiological responses, revealing distinct clusters of entropy profiles. The analysis identified two to four classes of responses, representing different phases of the marathon for individual runners, with some clusters clearly distinguishing the beginning, middle, and end of the race. This variability emphasizes the personalized nature of physiological responses and pacing strategies, reinforcing the need for individualized approaches. These findings offer practical applications for optimizing pacing strategies, suggesting that real-time monitoring of entropy could enhance marathon performance by providing insights into a runner's physiological state and helping to prevent the onset of hitting the wall.

The effect of pore boundary shape on the performance of catalytic self-pumping membranes and channels

Many technologies demand highly controllable membranes, including lab-on-a-chip systems, microfluidic sensors, and electrochemical cells. The pumps for these systems can be scaled down by many orders of magnitude with electrochemical pumps, and more still with recently invented membrane pumps. Such pumps have been demonstrated to independently pump fluid via catalytic reactions that create and consume H+ cations on opposite sides of the membrane. Our prior work showed that the mechanism behind this phenomenon was a self-generated electric field driving the fluid flow caused by the space charge polarization due to the electrochemical reactions. However, that work assumed that the pores inside a membrane were perfectly cylindrical, which is not always true. This work investigates more complicated and realistic structures that deviate from a perfectly cylindrical shape, as is typical of actual track-etched or polymeric membranes. The pore structures were studied using a 2D model, which solved the Poisson-Nernst-Planck-Stokes equations in COMSOL 5.5. Based on our previously validated model, we examine the impact of different parameters on self-pumping flow rates, including pore width, contracting/expanding variation, pore length, and pore inclination angle. According to the results, the self-pumping flow rate is more sensitive to pore width than pore length. Regarding the effects of pore defects, membranes with complicated shapes of contracting/expanding pores and cross-linked connecting pores should follow the same pattern as those membranes with straight pores and similar pore size; likewise, pore inclination does not significantly influence self-pumping flow. Therefore, the conclusions we obtained for cylindrical straight pores are still applicable. The results highlight the potential of utilizing catalytic reactions to manipulate liquid via actual track-etched membranes.

Efficient Redirection of Trapped Broad-Band Fluorescence from Substrates into Free Space Using c-Si Metasurfaces.

Fluorescent dye films on transparent substrates are essential for OLEDs, flexible displays, X-ray detection, and wireless optical communications. However, their efficiency is often hampered by fluorescence trapping due to total internal reflection (TIR) and waveguiding. This study tackles this longstanding challenge by reconceptualizing the integration of dye films with nanoantenna metasurfaces. Traditional methods involve directly spin-coating films onto c-Si metasurfaces on quartz substrates, resulting in edge luminescence and weak inner signals. We present a straightforward, adjustable approach by integrating dye films on the opposite side of quartz substrates, reaching a 2.5-fold photoluminescence enhancement and improving the uniformity of the emission compared to the conventional methods. These gains stem from redirecting a significant portion of leaked fluorescence light trapped inside the substrate into free space, surpassing TIR conditions through in-plane diffraction orders of the metasurfaces across the full RGB spectrum. Our findings facilitate the design of more efficient luminescent devices.

Structure of the human TIP60-C histone exchange and acetyltransferase complex.

Chromatin structure is a key regulator of DNA transcription, replication and repair1. In humans, the TIP60-EP400 complex (TIP60-C) is a 20-subunit assembly that affects chromatin structure through two enzymatic activities: ATP-dependent exchange of histone H2A-H2B for H2A.Z-H2B, and histone acetylation. In yeast, however, these activities are performed by two independent complexes-SWR1 and NuA4, respectively2,3. How the activities of the two complexes are merged into one supercomplex in humans, and what this association entails for the structure and mechanism of the proteins and their recruitment to chromatin, are unknown. Here we describe the structure of the endogenous human TIP60-C. We find a three-lobed architecture composed of SWR1-like (SWR1L) and NuA4-like (NuA4L) parts, which associate with a TRRAP activator-binding module. The huge EP400 subunit contains the ATPase motor, traverses the junction between SWR1L and NuA4L twice and constitutes the scaffold of the three-lobed architecture. NuA4L is completely rearranged compared with its yeast counterpart. TRRAP is flexibly tethered to NuA4L-in stark contrast to its robust connection to the completely opposite side of NuA4 in yeast4-7. A modelled nucleosome bound to SWR1L, supported by tests of TIP60-C activity, suggests that some aspects of the histone exchange mechanism diverge from what is seen in yeast8,9. Furthermore, a fixed actin module (as opposed to the mobile actin subcomplex in SWR1; ref. 8), the flexibility of TRRAP and the weak effect of extranucleosomal DNA on exchange activity lead to a different, activator-based mode of enlisting TIP60-C to chromatin.

Interaction-enhanced nesting in spin-fermion and Fermi-Hubbard models

The spin-fermion (SF) model postulates that the dominant coupling between low-energy fermions in near critical metals is mediated by collective spin fluctuations (paramagnons) peaked at the Néel wave vector, QN, connecting hot spots on opposite sides of the Fermi surface. It has been argued that strong correlations at hot spots lead to a Fermi surface deformation (FSD) featuring flat regions and increased nesting. This conjecture was confirmed in the perturbative self-consistent calculations when the paramagnon propagator dependence on momentum deviation from QN is given by χ−1∝|Δq|. Using diagrammatic Monte Carlo (diagMC) technique we show that such a dependence holds only at temperatures orders of magnitude smaller than any other energy scale in the problem, indicating that a different mechanism may be at play. Instead, we find that a χ−1∝|Δq|2 dependence yields a robust finite-T scenario for achieving FSD. To link phenomenological and microscopic descriptions, we applied the connected determinant diagMC method to the (t−t′) Hubbard model and found that at large U/t>5.5 before the formation of electron and hole pockets (i) the FSD defined as a maximum of the spectral function is not very pronounced; instead, it is the lines of zeros of the renormalized dispersion relation that deforms toward nesting, and (ii) the static spin susceptibility is well described by χ−1∝|Δq|2. Flat FS regions yield a nontrivial scenario for realizing a non-Fermi liquid state. Published by the American Physical Society 2024

A Modular Biosensor Design for Quantitative Measurement of Free Nedd8.

The objective of our study was to develop a genetically encoded biosensor for quantification of Nedd8, a post-translational modifier that regulates cellular signals through conjugation to other proteins. Perturbations in the balance of free (i.e., unconjugated) and conjugated Nedd8 caused by defects in Nedd8 enzymes or cellular stress are implicated in various diseases. Despite the biological and biomedical importance of Nedd8 dynamics, no method exists for direct quantification of free Nedd8, hindering the study of Nedd8 and activities of its associated enzymes. Genetically encoded biosensors are established as tools to study other dynamic systems, but limitations of current biosensor design methods make them poorly suited for free Nedd8 quantification. We have developed a modular method to design genetically encoded biosensors that employs a target binding domain and two reporter domains positioned on opposite sides of the target binding site. Target quantification is based on competition between target binding and the interaction of the reporter domains. We applied our design strategy to free Nedd8 quantification by developing a selective binder for free Nedd8 and combining it with fluorescent or split nanoluciferase reporters. Our sensors produced quantifiable and specific signals for free Nedd8 and enabled real-time monitoring of deneddylation by DEN1 with a physiological substrate. Our sensor design will be useful for high-throughput screening for deneddylation inhibitors, which have potential in treatment of cancers such as acute lymphoblastic leukemia. The modular design strategy can be extended to develop genetically encoded quantitative biosensors for other proteins of interest.

Effects of Loading Forces, Loading Positions, and Splinting of Two, Three, or Four Ti-Zr (Roxolid®) Mini-Implants Supporting the Mandibular Overdentures on Peri-Implant and Posterior Edentulous Area Strains.

Clinical indications for the Ti-Zr alloy (Roxolid®) mini-implants (MDIs) in subjects with narrow ridges are still under review. The aim was to analyze peri-implant and posterior edentulous area strains dependent on the MDI number, splinting status, loading force, and loading position. Six models were digitally designed and printed. Two, three, or four Ti-Zr MDIs, splinted with a bar or unsplinted (single units), supported mandibular overdentures (ODs), loaded with 50-300 N forces unilaterally, bilaterally, and anteriorly. The artificial mucosa thickness was 2 mm. Strain gauges were bonded on the vestibular and oral peri-implant sides of each MDI, and on the posterior edentulous area under the ODs. Loadings were performed through the metal plate placed on ODs' artificial teeth (15 times repeated). Arithmetic means with standard deviations and the significance of the differences (MANOVA, Sheffe post hoc) were calculated. Different MDI numbers, loading positions, forces, and splinting elicited different peri-implant microstrains. In the two-MDI models, 300 N force during unilateral loading elicited the highest microstrains (almost 3000 εμ on the loaded side), which can jeopardize bone reparation. On the opposite side, >2500 εμ was registered, which represents high strains. During bilateral loadings, microstrains hardly exceeded 2000 εμ, indicating that bilateral chewers or subjects having lower forces can benefit from the two Ti-Zr MDIs, irrespective of splinting. However, in subjects chewing unilaterally, and inducing higher forces (natural teeth antagonists), or bruxers, only two MDIs may not be sufficient to support the OD. By increasing implant numbers, peri-implant strains decrease in both splinted and single-unit MDI models, far beyond values that can interfere with bone reparation, indicating that splinting is not necessary. When the positions of the loading forces are closer to the implant, higher peri-implant strains are induced. Regarding the distal edentulous area, microstrains reached 2000 εμ only during unilateral loadings in the two-MDI models, and all other strains were lower, below 1500 εμ, confirming that implant-supported overdentures do not lead to edentulous ridge atrophy.

Photogrammetry protocol in babies with congenital torticollis: part 1 – inter-arch intraoral assessment

Torticollis is defined as an imbalance of the sternocleidomastoid muscle (SCM), with less extension of the neck, resulting in a preference to turn the head more from one side to the other. The characteristics frequently found are: ear contralateral to the torticollis displaced forward, facial asymmetry, and contralateral occipital flattening, as well as a smaller ipsilateral eye, causing misalignment of the eyes. This condition can also cause mandibular inclination (MI), in the frontal plane, with a difference in opening between the maxilla and mandible from one side or the other. The diagnosis and treatment of torticollis are routinely carried out by the physiotherapist and the diagnosis of this mandibular inclination is traditionally through visual examination. This assessment of mandibular inclination, carried out by the dentist, in an objective manner, can contribute to the diagnosis and also to the monitoring of proposed treatments that should reduce mandibular asymmetries. The objective of this study was to create a protocol for objective measurement of the distance between the maxilla and mandible, on the right and left sides, using photogrammetry, to detect whether mandibular inclination can be observed by the shorter inter-arch distance on the side corresponding to the torticollis. Case reports of two babies (1 baby aged 9 months and another aged 1 year and 1 month), diagnosed with congenital torticollis. Photogrammetry was carried out: the babies were positioned on a dental stretcher and photographed in maximum opening, intermediate, and closing positions. Using the photos and the IMAGE J program, measurements between the maxilla and mandible were taken (see photogrammetry description). Results: The measurement protocol used in both babies confirmed the greater mandibular inclination by approaching the hemi-arch corresponding to the side of the torticollis, compared to the opposite side. Objective measurement of mandibular inclination can be part of the timely diagnosis for congenital torticollis. Studies with an adequate sample size and methodology are necessary to confirm this diagnostic tool.

On the evolution of β1/β′ coupled-structures in Mg–Y–Nd alloys: A simulation study

In magnesium alloys based on the Mg–Y–Nd system, the key strengthening precipitate phases, β1 and β′, often form coupled-structures, with β′ precipitates invariably attached to both ends of the β1. A question here is how the attached β′ precipitates evolve as the β1 lengthens within the solid magnesium matrix. To investigate this, this study uses a multi-scale model based on a three-dimensional phase field approach to simulate the evolution of β1 and β′ precipitates in a β1/β′ coupled-structure. The simulation results reveal that, during the evolution process, the β1 precipitate lengthens, while the attached β′ precipitates grow only at the side located along the direction of β1 extension and dissolves at the opposite side. This results in a visual effect where the β′ precipitates appear to “move” within the solid matrix. This phenomenon is governed by the interplay between chemical free energy and elastic strain energy. Chemical free energy promotes uniform growth of the β′ precipitates. However, the elastic strain energy, generated by the β′ precipitates and the stress field concentrated at the end of the β1 plate to which they are attached, favours growth of only one side of the β′ precipitates while causing dissolution at the other side. When the evolution of a coupled-structure is influenced by neighbouring coupled-structures, the evolution of β′ precipitates is strongly driven by the minimization of elastic strain energy. In general, the β′ precipitates tend to grow under tensile stress fields and dissolve under compressive stress fields.

Ultrasonographic Evaluation of Morphological Changes in Peripheral Nerves after Traumatic Injury and Nerve Repair - A Prospective Study.

Purpose Ultrasound (US) has gained in importance for the visualization of morphological changes of injured nerves. After surgical repair, changes in neural structures are seen over time. The correlation of morphologic changes in US with the corresponding nerve function is uncertain. The aim of this study is to determine a correlation of post-traumatic morphological nerve changes with US and with nerve function after surgery. Materials and Methods This dual-center, prospective cohort study was conducted between 2017 and 2022 and included 20 mixed sensory motor nerve lesions. Patients were followed up clinically (sensitivity, pain, and motor function) with US and electroneuromyography. We determined the US changes of the nerves including the interaction of the tissue after nerve repair and any correlation with nerve function. With US nerve cross-sectional area (CSA), the number of traversing fascicles, hypo-echogenicity, and presence of perineural scar were analyzed. Results 20 lesions (12 median and 8 ulnar nerves) of 18 patients with intraoperatively confirmed nerve injury of at least 50% in the forearm were included. The average CSA was over 20 mm 2 throughout the follow-up period, corresponding to a neuroma in continuity compared to the opposite side (10.75 mm 2 ). Sensibility and motor function at 12 months were 6xS3/4 and 10xM3-5. There was a statistically significant correlation between continuous fascicles on US at 6 months and sensitivity at 12 months. Conclusion This study supports the presence of post-traumatic morphological changes in nerve fibers with US after traumatic injury. Morphological changes in nerve structure after trauma can be detected with US indicating a correlation between continuity of nerve fascicles and development of sensitivity and motor function.

Successful modified CLEAN-NET with semicircular seromuscular layer incision for a gastric GIST near the cardia: a case report and video demonstration

BackgroundThe combination of laparoscopic and endoscopic approaches to neoplasia with a non-exposure technique (CLEAN-NET) is a laparoscopic and endoscopic cooperative surgery (LECS). It combines laparoscopic gastric resection and endoscopic techniques for local resection of gastric tumors, such as gastrointestinal stromal tumors (GIST), with minimal surgical margins. A conventional CLEAN-NET surgical procedure is complex, requiring careful techniques to preserve the cardia, particularly in case of nearby lesions. We describe the case of a patient who underwent a modified CLEAN-NET approach with a semi-circular seromuscular layer incision surrounding the base of the tumor, different from a circular shape seromuscular layer in the conventional CLEAN-NET: around the tumor to preserve mucosal continuity, which acts as a barrier to avoid intraoperative tumor dissemination.Case presentationA 43-year-old woman was referred to our hospital because of a gastric submucosal tumor near the cardia, detected on medical examination. The patient was diagnosed with gastric GIST based on the results of endoscopic ultrasound-guided fine-needle aspiration. Modified CLEAN-NET was performed with a semicircular incision of the seromuscular layer on the opposite side of the cardia, making the surgical procedure simple and minimizing partial resection of the gastric wall, including the tumor, while preserving the cardia. The operative time was 147 min, preoperative blood loss volume was 3 mL, and postoperative hospital stay was 9 days. The resected specimen revealed a minimal resection of the gastric wall, including the tumor. The cardia and gastric nerves were preserved, and the postoperative food intake was good.ConclusionsThe modified CLEAN-NET with semicircular seromuscular layer dissection is a simple and reliable surgical procedure for GIST near the cardia.

First Detections of Ionospheric Plasma Density Irregularities from GOES Geostationary GPS Observations during Geomagnetic Storms

In this study, we present the first results of detecting ionospheric irregularities using non-typical GPS observations recorded onboard the Geostationary Operational Environmental Satellites (GOES) mission operating at ~35,800 km altitude. Sitting above the GPS constellation, GOES can track GPS signals only from GPS transmitters on the opposite side of the Earth in a rather unique geometry. Although GPS receivers onboard GOES are primarily designed for navigation and were not configured for ionospheric soundings, these GPS measurements along links that traverse the Earth’s ionosphere can be used to retrieve information about ionospheric electron density. Using the radio occultation (RO) technique applied to GPS measurements from the GOES–16, we analyzed variations in the ionospheric total electron content (TEC) on the links between the GPS transmitter and geostationary GOES GPS receiver. For case-studies of major geomagnetic storms that occurred in September 2017 and August 2018, we detected and analyzed the signatures of storm-induced ionospheric irregularities in novel and promising geostationary GOES GPS observations. We demonstrated that the presence of ionospheric irregularities near the GOES GPS RO sounding field of view during geomagnetic disturbances was confirmed by ground-based GNSS observations. The use of RO observations from geostationary orbit provides new opportunities for monitoring ionospheric irregularities and ionospheric density.

In-flight Energy Calibration of the GECAM Gamma-ray Detectors

The Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) mission is designed to monitor the Gamma-Ray Bursts (GRBs) associated with gravitational waves and other high-energy transient sources. The mission consists of two microsatellites which are planned to operate at the opposite sides of the Earth. Each GECAM satellite could detect and localize GRBs in about 8 keV–5 MeV with its 25 Gamma-Ray Detectors (GRDs). In this work, we report the in-flight energy calibration of GRDs using the characteristic gamma-ray lines in the background spectra, and show their performance evolution during the commissioning phase. Besides, a preliminary cross-calibration of energy response with Fermi GBM data is also presented, validating the energy response of GRDs.

Superior Measurement Accuracy of Digital Thickness Gauge Versus Digital Vernier Caliper in Determining Venous Tissue Thickness.

Background In determining mechanical characteristics, the accuracy of the thickness of the specimens can influence the biomechanical behavior, especially in the case of human tissues, where there is an important variability. This study aims to compare the accuracy of two routine measuring instruments, i.e., the digital vernier caliper and the digital thickness gauge, when measuring the thickness of venous specimens multiple times. Methodology In this study, we used 12 tubular vena cava specimens obtained from common breed pigs aged 18-24 weeks at the time of sacrifice from a local slaughterhouse. The measurements were performed using a digital vernier caliper (Multicomp PRO MP012475) for the first four protocols and a digital thickness gauge (Mitutoyo 547-500S) for the fifth protocol. In the first protocol, three measurements were taken on the same side, and their average was recorded as the sample thickness. The second protocol involved taking measurements on two opposite sides, and the average of these measurements was recorded as the sample thickness. In the third protocol, the thickness of each side was measured at its midpoint, and the average of the four measurements was recorded as the sample thickness. In the last protocol using a digital vernier caliper, the thickness of the vernier specimens was calculated as the average of the measurements taken at each corner of the square sample. Finally, for the fifth protocol, three consecutive measurements were taken using the digital thickness gauge, and their average was recorded as the final thickness of the sample. Results In the first protocol, we observed lower values during the first measurement in comparison to the second (0.409 ± 0.063 vs. 0.536 ± 0.064, p < 0.0001) and the third (0.409 ± 0.063 vs. 0.528 ± 0.055, p = 0.0001). Moreover, with the second protocol, we observed lower values during the first two measurements in comparison to the third measurement (p = 0.0279 and p = 0.0054). Regarding protocols three and four, we recorded higher values for the second and third measurements than the first one, with higher values for the third measurement than the second one. In the fifth protocol, there were no significant statistical differences between the three consecutive measurements (p = 0.953, p = 0.742, and p = 0.897). Further, we examined the variations in sample thickness determined using each of the protocols proposed for the digital vernier caliper, as well as the values obtained with the digital thickness gauge protocol. As a result, during the first and second measurements, we observed lower thickness values for the venous wall samples using the first four protocols compared to the fifth protocol (for all p < 0.05). However, no differences were noted between the five protocols during the third measurement. Conclusions The digital thickness gauge Mitutoyo 547-500S provided superior accuracy with no difference between three successive measurements of venous wall thickness, regardless of the examiner's experience. Accurately determining the thickness of venous specimens is crucial for calculating the tissue's biomechanical properties.

Disposable (Textual) Bodies

The present article compares two coeval authors, Daniel Defoe (1660-1731) and Jane Barker (1652–1732), who stand on opposite sides of the political and religious spectrum, to analyse the ways in which they engage with popular prostitute stories in Moll Flanders (1722) and the Patch-Work narratives (1723, 1726), respectively. This contribution, then, offers novel insights into these writers’ work, exploring the ways in which Defoe rewrites this form of popular fiction to conform to his middle-class fantasy of personal development, and how Barker responds both to Defoe’s tales of prostitute ascent and the general taste for this fiction from her own ideological perspective. It will also expose their similarities, as they construct composite literary bodies of many different prostitute narratives, and emphasize the need to understand the novel as an assemblage of voices, genres and sociomaterial aspects.

Numerical investigation of wingtip aerodynamic interference of two flapping wings on opposite sides

Aerodynamic interference occurs at the wingtips when flying organisms fly in a V formation. In this paper, the wingtip aerodynamic interference of two flapping wings on opposite sides at low Reynolds numbers (Re) is numerically investigated. The effects of streamwise spacing (L1), spanwise spacing (L2), and phase angle (γ) on aerodynamic performance are considered. The results show that, compared to a single wing, a favorable combination of L1 and L2 can improve the overall thrust by 24% while keeping the overall lift essentially unchanged. In an unfavorable case, overall lift and thrust decrease by 18% and 20%, respectively. The overall aerodynamic forces are dominated by the rear wing. Analyzing the essential flow characteristics reveals the double-edged role of downwash and upwash in force generation. Moreover, it is found that the rear wing can realize the upwash/downwash exploitation by flap phasing, turning an unfavorable situation into a favorable one. The key flow physics behind this transformation lies in the relationship between the direction of wing motion and the direction of fluid velocity induced by vortices. These findings provide valuable insights into the understanding of biological phenomena and the design of new flapping wing vehicles.

Application of optical fiber distributed acoustic sensing system in ultrasonic detection

Abstract The optical fiber distributed acoustic sensing system can continuously detect acoustic signals along the optical fiber, with the characteristics of wide response frequency band, large capacity, anti-electromagnetic interference and so on. An ultra-sensitive distributed optical fiber acoustic sensing system (uDAS) was produced with a high response frequency up to 100 kHz and thousands of sensing points. The arrayed ultrasonic detection can be realized by the distributed characteristics of the system. For verifying its ultrasonic detection ability, it is applied to ultrasonic nondestructive testing of structural defects. 20 optical fiber ultrasonic detection units were constructed. Each one is a fiber ring with a diameter of about 1.5 cm and a length of 2 meters. Two cubic cement structures with a side length of 30 cm were manufactured for experiment, one of which had an artificial internal defect. The optical fiber array was attached to the surface of the cement structure, and the ultrasonic signal with a frequency of 40 kHz was excited at a single point on the opposite side. The ultrasonic propagation speed changes on account of the defects such as holes and loose texture in the propagation path. The defects in the structure are identified and located by analyzing the difference of arrival time of waves. It is expected that such sensing system could found important applications in structure defect detection.

Intestinal vascular diseases misdiagnosed as Crohn ​disease: analysis of 13 cases

Behçet ​disease (BD), enterocolic lymphocytic phlebitis (ELP), idiopathic myointimal hyperplasia of mesenteric veins (IMHMV), and mesenteric arteriovenous dysplasia/vasculopathy (MAVD/V) are rare vascular diseases (VDs) that cause bowel ischaemia, often presenting with a histological pattern resembling chronic enteritis, leading to diagnostic confusion with Crohn ​disease (CD). In this retrospective study, we compared the clinical and pathological characteristics of these VDs with those of CD. The study cohort comprised 13 patients misdiagnosed with CD but later identified as having VDs, including five, three, two, and three patients with BD, ELP, IMHMV, and MAVD/V, respectively. Moreover, 15 patients diagnosed with CD served as the control group. Data on disease history, patient demographics, symptoms and signs, endoscopic findings, clinical diagnosis, and follow-up status were collected, and the histological features of VDs were compared with those of CD. Despite substantial overlap in clinical and pathological characteristics between VDs and CD, several histological features were helpful in differentiating the two conditions. Intestinal stenosis, multisegmental disease, transmural inflammation, inflammatory polyps, submucosal lymphangiectasia, intramural abscesses, and epithelioid granulomas were significantly more frequent in patients with CD (p<0.001). In contrast, toxic ischaemic changes and vascular lesions were significantly more frequent in patients with VDs (p<0.001). The location of diseased vessels varied widely in patients with VDs, whereas vascular changes were limited to areas with more severe inflammation in those with CD. Furthermore, inflammatory cells within diseased vessels exhibited a polarised distribution in cases of CD, manifesting in two distinct patterns: pattern 1, where the inflammatory cells are densely populated in the outer layer of the vessel wall and sparsely populated in the inner layer; pattern 2, where the inflammatory cells are densely populated on the side with the ulcer and sparsely populated on the opposite side. Vascular occlusion, which was observed in all patients with VDs, was rare in those with CD. In summary, VDs and CD can be distinguished through careful histological analysis, particularly focusing on characteristics of vascular changes, in combination with medical history.

Asymmetry of Microcirculation Parameters in Rats against the Background Conditions of LPS Administration.

The effect of intraperitoneal injection of LPS (pyrogenal, 100 μg/kg) on the asymmetry of the right-left hemodynamic balance of microcirculation (MCR) was studied in 10 male Wistar rats. Synchronous measurements of the MCR parameters of the outer surface of the symmetrical areas of the tail base were carried out by laser Doppler flowmetry. The coefficients of asymmetry of the regression relationships between changes in perfusion of each of the observation sides and the initial perfusion values of both the eponymous and opposite observation sides, as well as the mean values and coefficients of perfusion variation of the studied areas, were analyzed. Injection of pyrogenal changed parameters of the asymmetry of the right-left hemodynamic balance of MCR in comparison with the initial values. One hour after the injection of pyrogenal, the contribution of the left MCR bed to the right-left hemodynamic balance increased, and the right one decreased. At the same time, the value of the perfusion variation coefficient decreased on the left and increased on the right. The shift of the hemodynamic balance towards the left MCR bed led to significant increase in blood supply to the left MCR pool after pyrogenal injection. The results of the studies indicate a stress type of reaction of the animal body to the injected drug.

Fish-inspired tracking of underwater turbulent plumes

Autonomous ocean-exploring vehicles have begun to take advantage of onboard sensor measurements of water properties such as salinity and temperature to locate oceanic features in real time. Such targeted sampling strategies enable more rapid study of ocean environments by actively steering towards areas of high scientific value. Inspired by the ability of aquatic animals to navigate via flow sensing, this work investigates hydrodynamic cues for accomplishing targeted sampling using a palm-sized robotic swimmer. As proof-of-concept analogy for tracking hydrothermal vent plumes in the ocean, the robot is tasked with locating the center of turbulent jet flows in a 13,000-liter water tank using data from onboard pressure sensors. To learn a navigation strategy, we first implemented RL on a simulated version of the robot navigating in proximity to turbulent jets. After training, the RL algorithm discovered an effective strategy for locating the jets by following transverse velocity gradients sensed by pressure sensors located on opposite sides of the robot. When implemented on the physical robot, this gradient following strategy enabled the robot to successfully locate the turbulent plumes at more than twice the rate of random searching. Additionally, we found that navigation performance improved as the distance between the pressure sensors increased, which can inform the design of distributed flow sensors in ocean robots. Our results demonstrate the effectiveness and limits of flow-based navigation for autonomously locating hydrodynamic features of interest.