Test Object Research Articles

An Error Estimation System for Close-Range Photogrammetric Systems and Algorithms.

Close-range photogrammetry methods are widely used for non-contact and accurate measurements of surface shapes. These methods are based on calculating the three-dimensional coordinates of an object from two-dimensional images using special digital processing algorithms. Due to the relatively complex measurement principle, the accurate estimation of the photogrammetric measurement error is a non-trivial task. Typically, theoretical estimations or computer modelling are used to solve this problem. However, these approaches cannot provide an accurate estimate because it is impossible to consider all factors that influence the measurement results. To solve this problem, we propose the use of physical modelling. The measurement results from the photogrammetric system under test were compared with the results of a more accurate reference measurement method. This comparison allowed the error to be estimated under controlled conditions. The test object was a flexible surface whose shape could vary smoothly over a wide range. The estimation of the measurement accuracy for a large number of different surface shapes allows us to obtain new results that are difficult to obtain using standard approaches. To implement the proposed approach, a laboratory system for the error estimation of close-range photogrammetric measurements was developed. The paper contains a detailed description of the developed system and the proposed technique for a comparison of the measurement results. The error in the reference method, which was chosen to be phasogrammetry, was evaluated experimentally. Experimental testing of the stereo photogrammetric system was performed according to the proposed technique. The obtained results show that the proposed technique can reveal dependencies that may not be detected by standard approaches.

SeeSaw: Interactive Ad-hoc Search Over Image Databases

As image datasets become ubiquitous, the problem of ad-hoc searches over image data is increasingly important. Many high-level data tasks in machine learning, such as constructing datasets for training and testing object detectors, imply finding ad-hoc objects or scenes within large image datasets as a key sub-problem. New foundational visual-semantic embeddings trained on massive web datasets such as Contrastive Language-Image Pre-Training (CLIP) can help users start searches on their own data, but we find there is a long tail of queries where these models fall short in practice. Seesaw is a system for interactive ad-hoc searches on image datasets that integrates state-of-the-art embeddings like CLIP with user feedback in the form of box annotations to help users quickly locate images of interest in their data even in the long tail of harder queries. One key challenge for Seesaw is that, in practice, many sensible approaches to incorporating feedback into future results, including state-of-the-art active-learning algorithms, can worsen results compared to introducing no feedback, partly due to CLIP's high-average performance. Therefore, Seesaw includes several algorithms that empirically result in larger and also more consistent improvements. We compare Seesaw's accuracy to both using CLIP alone and to a state-of-the-art active-learning baseline and find Seesaw consistently helps improve results for users across four datasets and more than a thousand queries. Seesaw increases Average Precision (AP) on search tasks by an average of .08 on a wide benchmark (from a base of .72), and by a .27 on a subset of more difficult queries where CLIP alone performs poorly.

Chinese sign language recognition based on surface electromyography and motion information

Sign language (SL) has strong structural features. Various gestures and the complex trajectories of hand movements bring challenges to sign language recognition (SLR). Based on the inherent correlation between gesture and trajectory of SL action, SLR is organically divided into gesture-based recognition and gesture-related movement trajectory recognition. One hundred and twenty commonly used Chinese SL words involving 9 gestures and 8 movement trajectories, are selected as research and test objects. The method based on the amplitude state of surface electromyography (sEMG) signal and acceleration signal is used for vocabulary segmentation. The multi-sensor decision fusion method of coupled hidden Markov model is used to complete the recognition of SL vocabulary, and the average recognition rate is 90.41%. Experiments show that the method of sEMG signal and motion information fusion has good practicability in SLR.

Hemorheological changes in arterial hypertension in persons with and without COVID-19

BACKGROUND: Vascular resistance, and therefore blood pressure (BP), depends on vascular and rheological factors. Microrheological characteristics of red blood cells (RBCs) can affect blood viscosity (BV) and thus be included in the pathogenesis of increased blood pressure in arterial hypertension (AH). Signaling molecules such as gasotransmitters (NO, CO and H2S) regulate vascular tone and RBC microrheological characteristics and thus affect blood pressure and tissue perfusion. OBJECTIVE: It was evaluated the changes in the macro- and microrheological characteristics of blood and red blood cells (RBCs) under arterial hypertension in persons with and without COVID-19, as well as the protective effect of NO and H2S donors on the RBC microrheological properties. METHODS: Hemorheological profile parameters were recorded in group 1 individuals (n = 18, 9 women and 9 men) without a history of COVID-19; group 2 (n = 16; 11 females and 5 males), hypertensive patients who had COVID-19. As a control, there was a group of healthy individuals (group 3 n = 22). In experiments with red blood cells (RBCs) and their recovered ghosts (filled with an isotonic solution of known viscosity), deformability (RBCD) and aggregation (RBCA) were recorded after incubation of cells with sodium nitroprusside (SNP, 100μM) and sodium hydrosulfide (NaHS, 100μM). RESULTS: In patients with AH in both groups, the main parameters of the hemorheological profile were negatively changed, including a decrease in RBCD and an increase in BV, plasma viscosity (PV) and RBCA. SNP and NaHS significantly increased deformability and reduced their aggregation (p < 0.01). However, in healthy individuals, microrheological responses to GT donors (100μM) were more pronounced than in patients with AH, especially in the AH+COVID-19 group (p < 0.05). CONCLUSION: Both gasotransmitter donors (NO and H2S) have a positive effect on the RBC microrheological characteristics in healthy and sick individuals. However in hypertensive patients, especially those who had COVID-19, microrheological responses to GT donors were significantly lower. Therefore, on the model of red cell microrheological responses, as on a test object, it is possible to determine the decrease in the sensitivity of cells and tissues to the regulatory action of gasotransmitters.

Тестування на проникнення компонентів FPGA як сервісу для забезпечення кібербезпеки

The subject of study in this article is modern penetration testing technologies, in which the test object is a platform with access to FPGA resources. The goal of this work is to improve modern methods of penetration testing of services that provide FPGA as a Service, to identify vulnerabilities, the elimination of which increases the level of security of services and increases the level of user trust in such services. Task: to analyze possible threats of FPGA as a Service platforms; analyze the structure of FPGA as a Service platforms; analyze options for using the penetration testing standard; and offer key components for ensuring cyber security of FPGA as a Service platforms. According to the tasks, the following results were obtained. A study of the cyber security problems of FPGA as a Service platforms was conducted, and a set of components for ensuring the cybersecurity of FPGA as a Service platforms was proposed. An analysis of modern cybersecurity threats of FPGA as a Service platforms was carried out. The possibility of applying the penetration testing standard to FPGA services is considered. Regular audits and penetration testing are key elements of a cybersecurity strategy and help maintain customer and user trust in FPGA services. A set of components for ensuring cybersecurity of FPGA as a Service platforms is proposed, which corresponds to modern threats. The complex includes activities such as regular software updates, security monitoring and analysis, audit and penetration testing, compliance with security standards, and staff training. Conclusions. The main contribution and scientific novelty of the obtained results is that a study of the possibilities of penetration testing was conducted, where the test object is a platform with access to FPGA resources. As in many other areas, ensuring the cybersecurity of FPGA as a Service platforms is a complex task, where ignoring any component can lead to critical consequences. Applying only penetration testing is not enough; therefore, a comprehensive list of cybersecurity measures for FPGA as a Service platforms is provided.

Repair of Pier Bridge Model Post-Earthquake

This study concentrates on the bridge pier model which was damaged by the earthquake and repaired using grouting and carbon wrapping materials. This research consists of a one pier bridge model with two steps of testing, namely step 1 in the form of a cyclic test of the pier bridge model which will be followed by step 2 in the form of structural repairs with grouting and carbon wrapping materials and retesting. to evaluate the performance of the structural repair technology used. This research will show the cyclic test results using the repair material applied to the same sbr latex concrete material test object. The test object used is a pier bridge model with dimensions of 0.25×0.25×1.68 meters. The material specifications used are concrete f'c 30, fy 400 MPa deformed longitudinal reinforcement and stirrups fy 240 MPa. The test was carried out with a constant axial load of 0.2.f'c.Ag and a cyclic lateral load. Structural performance analysis was carried out according to ACI 374.1-05. Step 1 cyclic test was carried out until the drift ratio was 3.5%. The lateral peak strength achieved was 8.606 tonf with indications of shear damage indicated by the number of cracks in the web area. The second step of the cyclic test was carried out to a drift ratio of 6.25% with a lateral peak strength of 8.640 tonf with indications of flexural damage. Cyclic test results show that repair with a grouting material and carbon wrap can restore peak strength, deformation capacity, and stiffness degradation.

Pengaruh Penggunaan Limbah Masker Medis dan Limbah Serabut Kelapa sebagai Substitusi Pasir dalam Pembuatan Bata Ringan

Lightweight brick is a type of lightweight brick that is superior to the previous one. The purpose of this study was to analyze variations in the optimal composition of lightweight bricks (CLC) innovation by utilizing medical mask waste and coconut fiber waste as a substitute for sand based on bulk density and water absorption, compressive strength test, and soundproof test. The method used is the experimental method. Test object with variations in composition, namely 0%, 5%, 10% and 15%. Each variation has 3 samples with a total of 12. The values for bulk density and water absorption are in accordance with SNI 8640-2018. The compressive strength test was carried out using a cube specimen with a side of 15 cm aged 14 days. Soundproof test using a sound level meter. The results obtained at 10% variation with a mixture of 10% medical mask waste and 10% coconut fiber waste are the optimal composition in the manufacture of innovative lightweight bricks. The bulk density and water absorption were 0.0741%, the compressive strength test was 11.86 MPa, and the soundproof test was 24.3 dB. This lightweight brick innovation of 10% variation can be an alternative to smart, environmentally friendly and economical building materials.Keywords : Lightweight Brick (CLC), Medical Mask Waste, Coconut Fiber Waste, Content weight and Water absorption, Compressive Strength Test, Soundproofing Test

Modern Scanning Electron Microscopy. 2. Test objects for Scanning Electron Microscopy

The review of the test objects intended for calibration of scanning electron microscopes and researches to secondary electronic emission of a relief surface of a solid state in scanning electron microscope is carried out. The test objects are divided on two parameters – kind of a relief and structure of a relief. By the form of relief the test objects are divided on single, pitch and periodic. On a structure of a relief of the test objects are divided into objects with a rectangular structure and objects with a trapezoid structure with the large and small corners of an inclination of lateral walls. The examples of such the test objects are given. Their characteristics and methods of certification of parameters are described. The advantages and lacks of the test objects are considered. Is shown, that the best characteristics have the tests objects representing pitch structures consisting of trapezoid trenches with the large corners of an inclination of lateral walls. The test objects are created in monosilicon with of a surface orientation by {100} by method liquid anisotropic etching of silicon. These test objects allow defining all characteristics scanning electron microscopes, influencing on measurement of the linear sizes of relief structures used in microelectronics and nanotechnology. With their help it is possible to carry out correlation measurements, which raise accuracy of calibration scanning electron microscopes up to ten times.

Grain yield estimation of wheat-maize rotation cultivated land based on Sentinel-2 multi-spectral image: A case study in Caoxian County, Shandong, China

Establishing the remote sensing yield estimation model of wheat-maize rotation cultivated land can timely and accurately estimate the comprehensive grain yield. Taking the winter wheat-summer maize rotation cultivated land in Caoxian County, Shandong Province, as test object, using the Sentinel-2 images from 2018 to 2019, we compared the time-series feature classification based on QGIS platform and support vector machine algorithm to select the best method and extract sowing area of wheat-maize rotation cultivated land. Based on the correlation between wheat and maize vegetation index and the statistical yield, we screened the sensitive vegetation indices and their growth period, and obtained the vegetation index integral value of the sensitive spectral period by using the Newton-trapezoid integration method. We constructed the multiple linear regression and three machine learning (random forest, RF; neural network model, BP; support vector machine model, SVM) models based on the integral value combination to get the best and and optimized yield estimation model. The results showed that the accuracy rate of extracting wheat and maize sowing area based on time-series features using QGIS platform reached 94.6%, with the overall accuracy and Kappa coefficient were 5.9% and 0.12 higher than those of the support vector machine algorithm, respectively. The remote sensing yield estimation in sensitive spectral period was better than that in single growth period. The normalized differential vegetation index and ratio vegetation index integral group of wheat and enhanced vegetation index and structure intensify pigment vegetable index integral group of maize could more effectively aggregate spectral information. The optimal combination of vegetation index integral was difference, and the fitting accuracy of machine learning algorithm was higher than that of empirical statistical model. The optimal yield estimation model was the difference value group-random forest (DVG-RF) model of machine learning algorithm (R2=0.843, root mean square error=2.822 kg·hm-2), with a yield estimation accuracy of 93.4%. We explored the use of QGIS platform to extract the sowing area, and carried out a systematical case study on grain yield estimation method of wheat-maize rotation cultivated land. The established multi-vegetation index integral combination model was effective and feasible, which could improve accuracy and efficiency of yield estimation.

A theragnostic HIFU transducer and system for inherently registered imaging and therapy.

One big challenge with high intensity focused ultrasound (HIFU) is the difficulty in accurate prediction of focal location due to the complex wave propagation in heterogeneous medium even with imaging guidance. This study aims to overcome this by combining therapy and imaging guidance with one single HIFU transducer using the vibro-acoustography (VA) strategy. Based on the VA imaging method, a HIFU transducer consisting of 8 transmitting elements was proposed for therapy planning, treatment and evaluation. Inherent registration between the therapy and imaging created unique spatial consistence in HIFU transducer's focal region in the above three procedures. Performance of this imaging modality was first evaluated through in-vitro phantoms. In-vitro and ex-vivo experiments were then designed to demonstrate the proposed dual-mode system's ability in conducting accurate thermal ablation. Point spread function of the HIFU-converted imaging system had a full wave half maximum of about 1.2 mm in both directions at a transmitting frequency of 1.2 MHz, which outperformed the conventional ultrasound imaging (3.15 MHz) in in-vitro situation. Image contrast was also tested on the in-vitro phantom. Various geometric patterns could be accurately 'burned out' on the testing objects by the proposed system both in vitro and ex vivo. Implementation of imaging and therapy with one HIFU transducer in this manner is feasible and it has potential as a novel strategy for addressing the long-standing problem in the HIFU therapy, possibly pushing this non-invasive technique forward towards wider clinical applications.

The Effect of Hippo Pathway Inhibitor Xmu‐mp‐1 on Cognitive Impairment in a Rat Model of Alzheimer’s Disease: Protection against Oxidative Stress, Tau Hyperphosphorylation, and Neurodegeneration

AbstractBackgroundAlzheimer’s Disease (AD), the most common form of dementia, is a growing global health concern with unmet clinical therapeutics. AD can be attributed to amyloid beta aggregation and tau hyperphosphorylation‐induced oxidative stress and neurodegeneration in the brain. Previous studies have implicated a hyper‐activated Hippo signaling pathway with neuronal loss in neurodegenerative disorders, including AD. However, it is still unknown if suppressing the Hippo pathway can rescue neuronal death in AD.MethodIn this study, we investigated the cognitive impairment ameliorative effect of the novel Hippo signaling inhibitor, Xmu‐mp‐1, in a rat model of AD. Adult male Wistar rats were stereotaxically injected with a well‐known AD inducer Streptozotocin (STZ), to mimic AD‐like features. A pharmacological antagonist of Hippo signaling component MST1 called Xmu‐mp‐1 was administered intraperitoneally at a dose of 0.5mg/kg body weight for 14 days. Then the effect of Xmu‐mp‐1 on cognitive impairment was assessed using the Morris water maze test and novel object recognition test. Further, we did biochemical and histopathological studies to explore the effect of Xmu‐mp‐1 on several AD‐associated pathophysiological changes, including oxidative stress, tau hyperphosphorylation, and neurodegeneration.ResultXmu‐mp‐1 significantly improved the cognitive impairment of the AD rats in the Morris water maze test and the novel object recognition test (n = 7). Biochemical analysis of the brain hippocampal and cortical tissues revealed that Xmu‐mp‐1 also ameliorated the AD‐associated oxidative stress burden as the levels of anti‐oxidants (SOD, Catalase, GSH) significantly increased and the levels of oxidative stress biomarkers (protein carbonyl and lipid peroxidation) significantly reduced after Xmu‐mp‐1 treatment in the AD rats (n = 6). Moreover, the level of tau phosphorylation, a prime characteristic of AD, was also reduced following Xmu‐mp‐1 treatment (n = 3). Finally, neuronal death was also found to be rescued after Xmu‐mp‐1 treatment in AD rats (n = 3).ConclusionXmu‐mp‐1 exhibits a neuroprotective role against AD as it improves the cognitive impairment induced by STZ. Further mechanistic investigations into the neuroprotective role of Xmu‐mp‐1 revealed that Xmu‐mp‐1 provides protection from oxidative stress, tau hyperphosphorylation, and aberrant neurodegeneration under an AD background. Future studies can explore the therapeutic potential of Hippo signaling inhibition against AD in more detail.

Inpp5d deficiency exacerbates tau pathology and cognitive deficits in MAPTP301S mouse

AbstractBackgroundAlzheimer’s disease (AD) is the most common cause of dementia and is characterized by the cerebral accumulation of amyloid plaques and tauopathy. The gene inositol polyphosphate‐5‐phosphatase D (INPP5D), which encodes Src homology 2‐containing‐inositol‐phosphatase‐1 (SHIP1), has been highlighted by multiple approaches as a gene that modulates the risk for AD. SHIP1 expression in brain is restricted to inflammatory cells called microglia that have been shown to play significant roles in the induction and spread of tauopathy. Therefore, the goal of the current study was to examine the effect of microglial Inpp5d/SHIP1 knockdown on a mouse model of tauopathy.MethodWe generated a mouse model of conditional Inpp5d knockdown in microglia to assess the impact on pathology in the MAPTP301S mouse model of tauopathy, using Inpp5dflox mice crossed with an inducible Cx3cr1CreER/+. To induce recombination, 3‐month‐old (mo) Inpp5dfl/fl/Cx3cr1CreER/+ mice, with and without the MAPTP301S transgene, were injected for 5 consecutive days with either tamoxifen (TAM) or corn oil (CO). At 8.5 mo, we assessed learning behavior using the Barnes Maze test and Novel Object Recognition test. Finally, we performed immunohistochemistry, immunoblotting, and quantitative real‐time PCR to assess neuroinflammation and tau pathology.ResultTAM treatment of Inpp5dfl/fl/Cx3cr1CreER/+ mice and MAPTP301S /Inpp5dfl/fl/Cx3cr1CreER/+ mice was used to induce microglial Inpp5d deficiency in both lines. Microglial Inpp5d deficiency in MAPTP301S mice was associated with increased levels of AT8+ hyperphosphorylated tau, yet the numbers of IBA1+ microglia and GFAP+ astrocytes were similar to MAPTP301S expressing normal levels of Inpp5d.ConclusionOur findings suggest that, in our mouse model, Inpp5d deficiency plays an important role in the pathogenesis of tauopathy, but fails to induce an obvious increase in the numbers of either IBA1+ microglia or GFAP+ astrocytes. Our results provide evidence for further evaluation of INPP5D/SHIP1 as a potential target for treating and/or preventing AD.

Effect of Small Concaves Surface on the Acoustical Characteristics of Chicken Feather Panel

This study aims to determine the impact of small concave surfaces on the acoustic characteristics of chicken feather panels. Based on the feather-glue ratio reference, the researchers applied a mixture of 70% feather and 30% PVAc for the production of the specimens. In the first stage, the absorption coefficient of the specimen on a small concave surface (CS) was measured using an impedance tube type B&K 4602 with two microphones and a set of computer FFT analyzers. The measurement results were then compared with the absorption coefficient of similar test objects with flat surfaces (FS). The acoustic characteristics of the two types of surfaces (FS and CS) in the specimen panel showed the maximum absorption coefficient (α) value of 0.52 and 0.63 for FS and CS, respectively. These results indicate that specimens with a small concave surface (CS) have a relatively higher absorption coefficient than those with a flat surface (FS). However, further studies are needed to identify other characteristics of these acoustic panels, including their resistance to environmental influences.

Experimental and numerical investigations on the dynamic response of a power transformer

In the manufacturing unit, there is a need of an accurate and reliable numerical tool to predict noise radiation from transformer. The first step to achieve this is to have a proper modal analysis of the active part (winding+core+clamping system). An impact test was performed on a 30 MVA power transformer unit and resonance peaks were identified from the FFT plots. Also, Operational Deflection Shapes (ODS) were extracted to visualize the displacement pattern of the test object. Moreover, the transformer unit was electrically energized, and vibration levels were measured with Polytec 3D scanning laser vibrometer. A detailed numerical model was developed in COMSOL Multiphysics, and very good agreement was seen between the numerical and measurement results.

THEORETICAL AND METROLOGICAL JUSTIFICATION OF THE TEST
 TO DETERMINE THE LEVEL OF FORMATION OF STUDENTS'
 MOTOR THINKING

This article discusses one of the important tasks of physical education related to the formation of the foundations
 of motor thinking of students. In the work, from the position of the information approach, a theoretical model of motor
 thinking is presented as a system of neuro-semantic processing of information coming from the subject area and the
 development of an adequate motor response to it.
 
 The formation of motor thinking is impossible without the development of diagnostic tools to determine the level
 of its formation. Based on the theoretical model of motor thinking, the authors developed a metrologically correct test to
 determine the level of formation of students' motor thinking. The approbation of the test on thirty students of the Faculty
 of Physical Culture showed its adequacy to the object of testing, acceptable reliability and logical adequacy
 (informativeness) to the subject of testing. There was no statistically significant difference between the results of girls and
 boys both in the test and in the retest
 
 The test can be used to develop a methodology for forming the foundations of students' motor thinking.

BEHAVIOR OF FLAT REINFORCED-CONCRETE COLUMN SIZE (15x30) CM TO AXIAL CYCLIC LOADING : COMPARATION STUDY COLUMN WITH REINFORCEMENT AND STEEL PROFILE

This research discusses the behavior of flat columns with the comparison of reinforced-concrete columns and IWF steel reinforcement. The research object took 4 column samples with a column size of 15x30 cm by comparing the reinforced-concrete column and concrete columns with IWF steel reinforcement. This study conducted comparisons with experimental tests, column capacity theory calculations, and calculations with the ANSYS19.2 program. The purpose of this study was to obtain the maximum axial load result, shorten the column, the relationship between stress and strain of the column, failure pattern of the column, and the ability of the column to withstand the number of floors in the sample of the reinforced-concrete column and concrete columns with IWF steel reinforcement. The results of the average maximum axial load of the test object for each sample column in the experimental test for K1 is 119,6 tons, K2 is 146,18 tons, K3 is 146,6 tons, and K4 is 167,46 tons, the maximum axial load in the column capacity calculation for column sample K1 is 130 tons, K2 is 159 tons, K3 is 157 tons, and K4 is 180 tons, and the maximum axial load in the ANSYS 19.2 program for column sample K1 is 122,7 tons, K2 is 138,86 tons, K3 is 150,14 tons, and K4 is 159,62 tons. The failure pattern occurred in column sample K1 is in the column span area, for sample K2 in the column span and pedestal area, the K3 column in the pedestal area, and the K4 column in the pedestal area. K1 column sample withstand 2-floors, K2 and K3 columns withstand 3-floors, and K4 column withstand 4-floors.

Numerical and Experimental Investigation of Time-Domain-Reflectometry-Based Sensors for Foreign Object Detection in Wireless Power Transfer Systems

Foreign object detection (FOD) is considered a key method for detecting objects in the air gap of a wireless charging system that could pose a risk due to strong inductive heating. This paper describes a novel method for the detection of metallic objects utilizing the principle of electric time domain reflectometry. Through an analytical, numerical and experimental investigation, two key parameters for the design of transmission lines are identified and investigated with respect to the specific constraints of inductive power transfer. For this purpose, a transient electromagnetic simulation model is established to obtain and compare the sensor impedance and reflection coefficients with experimental data. The measurement setup is based on parametrically designed sensors in laboratory scale, using an EUR 2 coin as an exemplary test object. Consequently, the proposed simulation model has been successfully validated in this study, providing a comprehensive quantitative and qualitative analysis of the major transmission line design parameters for such applications.

Effects of electroacupuncture on the microvascular structure and related protein expression in the hippocampus of vascular dementia rats.

To explore the effect of electroacupuncture (EA) at "Baihui" (GV20) and "Shenting" (GV24) on the microvascular structure and related protein expression in the hippocampus of vascular dementia (VD) rat model, and to investigate the mechanism of EA in the treatment of VD. A total of 24 SD rats were randomly divided into sham operation, model, EA, and oxiracetam groups, with 6 rats in each group. Multiple cerebral infarction method was used to establish VD model. In the EA group, EA was applied to GV20 and GV24 for 30 min, once daily for 14 days. Rats in the oxiracetam group were treated with oxiracetam (50 mg/kg) by intraperitoneal injection, and the course of treatment was the same as that in the EA group. Learning and memory ability were evaluated by using Morris water maze test and new object recognition experiment. The cerebral blood flow was detected by laser doppler. The microvascular structure in the hippocampus was observed by transmission electron microscopy. The expression of vascular structure related proteins of platelet-derived growth factor receptor (PDGFR)-β, platelet endothelial cell adhesion molecule-1(CD31), neural cadherin N-Cadherin, Zonula occludens protein-1(ZO-1) in the hippocampus were measured by Western blot. Compared with the sham operation group, the rats in the model group had a significant increase in time of first crossing the platform, a significant decrease in the number of crossing platform and the new object preference index (P<0.05), a significant decrease in cerebral blood flow (P<0.05), and a significant increase in the brain weight (P<0.05). The structure boundary of pericyte and endothelial cells in the microvessels of the hippocampal CA1 area of model group was blurred, accompanied by obvious edema around the vessels and the reduction of tight junctions. The protein expression levels of PDGFR-β, CD31, N-Cadherin, ZO-1 were significantly decreased in the model group compared with those in the sham operation group (P<0.05). Compared with the model group, the time of first crossing the platform of rats in the EA and oxiracetam group was shortened, the number of crossing platform were increased (P<0.05), the cerebral blood flow was increased (P<0.05), the brain weight was decreased (P<0.05), the morphology and structure of pericyte and endothelial cells in the microvessels of hippocampal CA1 area were intact, accompanied by the increase of tight junctions. Additionally, Compared with the model group, the EA group had a significant increase in the new object preference index (P<0.05), the protein expression levels of PDGFR-β, CD31, ZO-1 in the EA group were increased (P<0.05), and the expression of PDGFR-β, N-Cadherin, ZO-1 in the oxiracetam group were increased (P<0.05). EA at GV20 and GV24 can improve the learning and memory ability of VD rats, and the mechanism may be related to the repair of microvascular structures and improvement of cerebral blood flow.

Characterization of Antenna Radiation Pattern and Penetration Depth in Ground Penetrating Radar Field Missions

This article discusses the methods and results of assessing the angular resolution and sounding depth of enhanced-power ground penetration radars obtained during archaeological and geographical expeditionary works in various natural areas. Elongated local objects were used as test objects to evaluate the horizontal radiation pattern of the Loza–V georadar in the upper- and lower-half spaces. The depth of operation of the Loza–N low-frequency radar was estimated during a geophysical study of a unique natural object in the Siberian taiga. The variability of the GPR antenna radiation patterns in different materials (air, dry, or wet soils) confirms the necessity of quantitative measurements with controlled electrophysical parameters.

Ag/ZIF‐8/polyacrylonitrile flexible SERS substrate with high sensitivity for the surface corrosion analysis

AbstractThe development of a novel and reliable surface‐enhanced Raman scattering (SERS) substrate for the surface corrosion analysis of bronze relics is an attractive research topic in cultural relic protection. A high‐performance SERS substrate was developed in the current investigation using Ag/ZIF‐8/Polyacrylonitrile (Ag/ZIF‐8/PAN) nanofibers. Silver nanoparticles were grown in situ by zeolite imidazolate framework‐8 (ZIF‐8) nanoparticles, and the substrate was examined in the surface corrosion analysis of bronze relics. In situ, growth of silver nanoparticles was ensured by the porous structure and active centers on ZIF‐8, coated on PAN nanofibers. Simultaneously, the adsorption of harmful rust‐alkaline copper chloride was enhanced on the surface of bronze relics. The extensive metal network was perturbed by the deposits, which substantially increased the intensity of the Raman characteristic peaks of the test objects. The signal strength of alkaline copper chloride at 118 cm−1 on the bronze surface increased from 1094 to 20,790. The exceptional SERS performance of silver nanoparticles with sharp edges demonstrates that the synergistic effect of ZIF‐8 nanoparticles and PAN nanofibers offers a considerable number of Raman‐enhanced hot spots. These results indicate that MOF‐based nanostructures offer a novel approach to enhancing the morphology of silver nanoparticles and expanding their potential applications in the field of cultural relic protection.