Vein Structure Research Articles

Anomalously light geological complex on the watershed plain of the Yano-Indigir lowland

The research method is a purposeful petrophysical interpretation of the gravitational field. The object under study appeared during prospecting geological and geophysical work as a hindrance to the solution of the main geological problem. Its density is 1 g/cm3, the height of the sole is 35 m, the area is 1420 km2, the volume is 20 km3. The object is defined as an abnormally light Ice Complex (ALIC). The revealed density is explained by peat-ice performance. In ALIC, a near-surface lenticular-layered formation ice has been uncovered, the structure of which indicates the generation of the mass of the complex ahead of sedimentation. The gravimetric data, the landscape and the details of the ALIC structure are interconnected and make up the first — the most complete view of the complex at the moment. The main elements of the presentation are the three phases of the development of the complex. The first is classical, generally accepted for polygonal—vein structures, the second differs from the classical one by the absence of frost-breaking cracking, the third is the growth of formation ice. The qualitative difference of the thermophysical components of the cryolithozone of the territory is given, which made it possible to introduce several concepts concerning the generation of peat-ice mass ALIC. Such as: heat dissipation capacity of the middle layer, stabilization of the zero isotherm at the petrophysical boundary; conditions for the beginning of the growth of lenticular-layered ice; accelerated lateral segregation growth of powerful ice veins; constancy of the thermal resistance of the cryolithozone. On the basis of these concepts, models of the development of the second and third phases of ALIC are compiled, and a view on the theory of the formation of cover glaciers is formed, which follows from the model of the third phase. The novelty of the research consists: in identifying a unique petrophysical object, in defining this object as ALIC, in identifying an ice massif on the territory of ALIC, in presenting the development of the complex as a sequence of three phases, in compiling models of the second and third phases of ALIC and in an original approach to the formation of cover glaciers.

In vivo, Antibacterial Effect of Green and Black Tea Extracts on Infected Liver and Kidney of Rats

The aim of this study is to investigate the antibacterial effect of hot and cold aqueous extracts of green and black tea separately against Klebsiella pneumoniae after infecting the burned rat's skin with it, also to screen the effect of both types of tea on rat's liver and kidney. Sixteen male rats divided into four Groups (4 animals each), Group 1: untreated rat (control). Group 2: burn rats infected with K. pneumoniae (1.5×108 bacteria /ml). Group 3: burn treated by Green tea aqueous extract (1000 µg/ml) for K. pneumoniae bacteria. Group 4: burn treated by black tea extract (2000 µg/ml) for K. pneumoniae bacteria. The tea extracts antimicrobial activity was analyzed by agar diffusion inhibition assay and minimum inhibitory concentration. Results exhibited that K. pneumoniae in particular, have high levels of antimicrobial resistance to widely used agents. In conclusion hot extract from both types of tea have better antibacterial effect than cold extract. Additionally, infected rats showed inflammation and sever hemorrhage in the liver and kidney of rats, but when treated with tea extracts dermally approximately restored kidney normal histological architecture of glomeruli and tubules, also liver became nearly normal in histological structure of hepatic foci and central vein. Black tea extract showed greater effectiveness in tissue recovery than green once.

Orogenic gold in the Blue Mountains, eastern Oregon, USA

At least 75% of gold produced in the State of Oregon came from the Blue Mountains. Most gold within the Blue Mountains was mined from orogenic gold veins and associated placer deposits. However, the geodynamic, regional, and deposit scale controls on orogenic gold mineralization within the Blue Mountains are not understood. Here, the mobilization, transport, deposition, and exposure of golds are linked to protracted tectonism of the western North American Cordillera through a scale-integrated mineral system. Gold production by mine (t) was estimated from public domain documents of production value (USD) and production time period (years). Lode endowment was then analyzed against criteria such as host rocks, vein structure, and location within the regional tectonic framework. Argillite, schist, and slate formed in accretionary wedge and fore-arc basins host the majority (∼60%; ∼29 t) of the total recorded gold production. Unique geochemical, geomechanical, and hydrological properties made these rock types excellent hosts. These properties were predetermined by both depositional setting (deep ocean basin) and metamorphic conditions (lower greenschist facies). Nearly half (50–55 %; ∼25.5 t) of recorded lode gold production was mined from lodes striking 030° ± 15° azimuth. A reconstructed paleo-stress field supports that these were left lateral faults. It is speculated that these were part of a margin-parallel shear zone that partitioned the strike slip component of oblique convergence between subducting oceanic plates and associated magmatic arcs. At both the district and the deposit scales, minor deviations in vein strike form local high-grade sites (i.e., dilatant zones). Such dilatant zones within major crustal shear zones could also explain the spatial, but not fluid-genetic association of granitic plutons with lode gold. The intersection lines between the veins, host rock fabrics, and secondary veins likely control the locations, thicknesses, and pitch of high-grade ore shoots.

Histological Response to 5 kHz Irreversible Electroporation in a Porcine Liver Model.

Unlike necrosis by thermal ablation, irreversible electroporation (IRE) is known to induce apoptosis by disrupting plasma membrane integrity with electric pulses while preserving the structure of blood vessels and bile ducts in liver tissue without a heat sink effect. This study aimed to investigate thermal damage and histopathological effects in the porcine liver by high-frequency electric pulses (5 kHz) which is much higher than the widely used 1 Hz. The electric field and thermal distributions of 5 kHz electric pulses were compared with those of 1 Hz in numerical simulations. 5 kHz-IRE was applied on pigs under ultrasound imaging to guide the electrode placement. The animals underwent computed tomography (CT) examination immediately and 1 day after IRE. After CT, IRE-treated tissues were taken and analyzed histologically. CT revealed that hepatic veins were intact for 1-day post-IRE. Histopathologically, the structure of the portal vein was intact, but endothelial cells were partially removed. In addition, the hepatic artery structure from which endothelial cells were removed were not damaged, while the bile duct structure and cholangiocytes were intact. The thermal injury was observed only in the vicinity of the electrodes as simulated in silico. 5 kHz-IRE generated high heat due to its short pulse interval, but the thermal damage was limited to the tissue around the electrodes. The histopathological damage caused by 5 kHz-IRE was close to that caused by 1 Hz-IRE. If a short-time treatment is required for reasons such as anesthesia, high-frequency IRE treatment is worth considering. Our observations will contribute to a better understanding of the IRE phenomena and search for advanced therapeutic conditions.

Anatomical Structures to Be Concerned With During Peripherally Inserted Central Catheter Procedures.

The central line has been frequently used for drug and nutrition supply and regular blood sampling of patients with chronic diseases. However, this procedure is performed in a highly sensitive area and has several potential complications. Therefore, peripherally inserted central catheters (PICC), which have various advantages, are being extensively used. Although the number of PICC procedures is increasing, the anatomy for safe procedures has not yet been properly established. Therefore, we studied basic anatomical information for safe procedures. We used 20 fixed cadavers (40 arms) donated to the Korea University College of Medicine. The mean age was 76.75 years (range, 48-94 years). After dissection of each arm, the distribution pattern of the basilic vein and close structures was recorded, and some important parameters based on bony landmarks were measured. In addition, the number of vein branches (axillary region) and basilic vein diameter were also checked. The mean length from the insertion site to the right atrium was 38.39 ± 2.63 cm (left) and 34.66 ± 3.60 cm (right), and the basilic vein diameter was 4.93 ± 1.18 mm (left) and 4.08 ± 1.49 mm (right). The data showed significant differences between the left and right arms (P < 0.05). The mean distance from the basilic vein to brachial artery was 8.29 ± 2.78 mm in men and 7.81 ± 2.78 mm in women, while the distance to the ulnar nerve was 5.41 ± 1.67 mm in men and 5.52 ± 2.06 mm in women. According to these results, the right arm has a shorter distance from the insertion site to the right atrium, and the left arm has a wider vein diameter, which is advantageous for the procedure. In addition, the ulnar nerve and brachial artery were located close to or behind the insertion site. Therefore, special attention is required during the procedure to avoid damaging these important structures.

MOLYBDENUM MINERALIZATION OF THE HANNIVKA DEPOSIT, KRYVYI RIH STRUCTURE

The Hannivka molybdenum deposit is located in the northeastern side of the Kryvyi Rih structure, within the East Hannivka monocline. Molybdenum mineralization is confined to the contact zone of granitoids of the Demuryne complex with metabasites of the Novokryvorizka suite. The main volume of molybdenum mineralization is concentrated in the exocontact, in metabasites, and only 10-15% in endocontact granitoids. The molybdenum-bearing zone is represented by schistose, moderately quartzized and biotitized fine-grained metabasalts, which contain quartz, epidote-quartz, epidote, sometimes feldspar-quartz veins and veinlets and moderate (0.5-3%) sulfide mineralization. The volume of vein material ranges from 0.5% to 3-5%. The geological-morphological type of mineralization is defined as linear stockwork. Leading processes responsible for the development of molybdenite are quartzization and biotitization, namely silicic-alkaline metasomatism. Using JSM-6700F і JXСА-733 electron microscopes, the following ore minerals have been diagnosed and studied: magnetite, ilmenite, molybdenite, loellingite, arsenopyrite, pyrrhotite, pyrite, chalcopyrite, sphalerite. Based on their structural positions and relationships, several successive ore stages have been identified: early oxide (ilmenite-magnetite), main sulfide with molybdenite, potentially gold-bearing arsenide-sulfoarsenide-sulfide and late sulfide. Molybdenite is localized in zalbands of thin (1-3 mm, occasionally up to 2 cm) quartz veinlets, sometimes in the form of boudinaged structures, lenses and pockets reaching sizes up to 4 cm, as well as in host metabasalts and plagiogranites. Conditionally, three morphological types of molybdenite can be distinguished: a) medium-sized elongated tabular, platy, and foliated crystals ranging in size from 0.1 mm to 1.5-2 mm, which are oriented subparallel to the vein structures and rock foliation; b) fine-grained (from 10-20 µm to 0.1 mm) elongated flakes uniformly or randomly oriented; с) isometric crystals of hexagonal-tabular habitus with sizes ranging from 0.1 to 0.7 mm. Outlined are several areas that require further investigation: epitaxial growths of molybdenite and silicates and the conditions of their formation, the time of formation of molybdenite and ore-generating granitoids.

Region Expansion of Background Field Removal with Local Spherical Harmonics Approximation for Whole-brain Quantitative Susceptibility Mapping.

Quantitative susceptibility mapping (QSM) is useful for obtaining biological information. To calculate susceptibility distribution, it is necessary to calculate the local field caused by the differences of susceptibility between the tissues. The local field can be obtained by removing a background field from a total field acquired by MR phase image. Conventional approaches based on spherical mean value (SMV) filtering, which are widely used for background field calculations, fail to calculate the background field of the brain surface region corresponding to the radius of the SMV kernel, and consequently cannot calculate the QSM of the brain surface region. Accordingly, a new method calculating the local field by expansively removing the background field is proposed for whole brain QSM. The proposed method consists of two steps. First, the background field of the brain surface is calculated from the total field using a locally polynomial approximation of spherical harmonics. Second, the whole brain local field is calculated by SMV filtering with a constraint term of the background field of the brain surface. The parameters of the approximation were optimized to reduce calculation errors through simulations using both a numerical phantom and a measured human brain. Performance of the proposed method with the optimized parameters was quantitatively and visually compared with conventional methods in an experiment of five healthy volunteers. The proposed method showed the accurate local field over the expanded brain region in the simulation studies. It also showed consistent QSM with conventional methods inside of the brain surface and showed clear vein structures on the brain surface. The proposed method enables accurate calculation of whole brain QSM without eroding the brain surface region while maintaining same values inside of the brain surface as the conventional methods.

Comparison of phrenic nerve injury and its effect on the extrapulmonary vein structures with cryoballoon and hot-balloon ablation systems: considering the lesion created on the superior vena cava as a surrogate marker.

Preventing phrenic nerve injury (PNI) during balloon-based ablation is essential. The superior vena cava-right atrial (SVC-RA) junction is located just opposite the balloon position during right superior pulmonary vein (RSPV) ablation, and the phrenic nerve runs nearby on the lateral side. We compared the occurrence of PNI between the two balloon-based ablation systems and also the lesions created at the SVC-RA junction, which were expected to represent the effect on extra-PV structures. Cryoballoon ablation (CBA, n = 110) and hot-balloon ablation (HBA, n = 90) were performed in atrial fibrillation patients. High-density maps of the SVC-RA junction were created in 93 patients (CBA = 53, HBA = 40), and the damaged area (< 1.0mV) was determined as an "SVC lesion". CBA had a higher occurrence of transient PNI (7.3% vs 1.1%, p = 0.035), but all recovered during the 6-month follow-up. An apparent SVC lesion was documented in 43% of the patients (40/93), and all patients with PNI had this lesion. CBA created a frequent (CBA vs HBA = 55% vs 28%, p = 0.008) and wider (0.8[0.4-1.7] cm2 vs 0.5[0.3-0.7] cm2, p = 0.005) SVC lesion than HBA. A multivariate analysis revealed that the use of a CBA system was a predictive factor of the occurrence of SVC lesions. CBA had a higher occurrence of transient PNI but not a permanent form. Every patient with PNI had lesions on the SVC-RA junction, and CBA revealed more substantial ablation effects at the SVC-RA junction than HBA. This may be caused by the different characteristics of the two balloon-based ablation systems and their balloon positions.

Morphometric and Hemodynamic Analysis of the Compressed Iliac Vein

Purpose: To investigate the relationship between the morphological structure and hemodynamic properties of the compressed iliac vein and explore the reason for the formation of thrombosis in the compressed iliac vein. Materials and Methods: A total of 11 patients with iliac vein compression syndrome (IVCS) were included in this study, and their iliac veins were reconstructed in 3 dimensions (3D). The morphological structures of the iliac veins (confluence angle, degree of stenosis) were analyzed based on the 3D model. Variations in the hemodynamic properties of the iliac vein were investigated at 4 typical moments in one cardiac cycle, and the relationship between the different morphological configurations and the pressure difference was investigated. Results: In the region of the compressed iliac vein, the blood flow velocity is accelerated and the pressure changes abruptly accompanied by the increase in pressure difference. Higher time averaged wall shear stress (TAWSS) and lower relative residence time (RRT) appeared in stenosis regions of compressed iliac vein, while TAWSS was low and RRT was large near the stenosis position. There was a strong positive correlation between the degree of stenosis and the pressure difference (r=0.894), and a positive correlation between the confluence angle of the iliac vein and the pressure difference (r=0.638). Conclusion: The morphological structure of the compressed iliac vein has an obvious influence on the hemodynamic surroundings; the pressure difference becomes larger when the degree of stenosis and the confluence angle increase. The iliac vein luminal areas with low TAWSS and high RRT near the compressed location can impede blood flow and lead to accumulation of blood components, which may increase the risk of thrombosis formation and should be fully considered in the treatment of IVCS.

Near Infrared Illumination Optimization for Vein Detection: Hardware and Software Approaches

Venepuncture is one of the most crucial processes in many medical procedures. However, finding a real-time and vibrant visualization of the vein structures faces many difficulties. Several devices were introduced to solve this problem, yet, these devices shared common drawbacks, primarily when visualizing deep veins or veins in a thicker tissue of the human body. This study proposes a novel method for visualizing vein structures using a near-infrared (NIR) imaging technique enhanced with Hessian ridge detection. Several factors, including the wavelength of NIR light, square LED and ring LED arrangement and the effect of the diffuser and number of LEDs, were evaluated in the study. This study improves the overall quality of the acquired vein images and highlights the vein-morphological structure through image processing techniques. The study’s main aim is to achieve the highest number of visible veins. Based on the optical window, the maximum absorption range in the NIR spectrum was found from 700 to 950 nm. The NIR light absorption of human deoxygenated blood in the vein was highest at 850 nm peak of wavelength. The image processing further enhances the vein image by highlighting the extracted vein. The study also suggests that the square LED arrangements of NIR illumination are much more robust than the ring LED arrangement in ensuring excellent light penetration. The light diffuser further adds promising effects to the NIR illumination process. In terms of the square LED arrangement, increasing the square LED for enlarging the illumination area did not show any degradation effects in the visualization process. Overall, this paper presents an integrated hardware and software solution for the NIR image acquisition of a vein visualization system to cope with the image visualization of the vein for a thicker part of the human tissue, particularly on the arm and palm area.

A review of natural hydrofractures in rocks

AbstractHydrofractures, or hydraulic fractures, are fractures where a significantly elevated fluid pressure played a role in their formation. Natural hydrofractures are abundant in rocks and are often preserved as magmatic dykes or sills, and mineral-filled fractures or mineral veins. However, we focus on the formation and evolution of non-igneous hydrofractures. Here we review the basic theory of the role of fluid pressure in rock failure, showing that both Terzaghi’s and Biot’s theories can be reconciled if the appropriate boundary conditions are considered. We next discuss the propagation of hydrofractures after initial failure, where networks of hydrofractures may form or hydrofractures may ascend through the crust as mobile hydrofractures. As fractures can form as a result of both tectonic stresses and an elevated fluid pressure, we address the question of how to ascertain whether a fracture is a hydrofracture. We argue that extensional or dilational fractures that formed belowc.2–3 km depth are, under normal circumstances, hydrofractures, but at shallower depth they may, but must not be hydrofractures. Since veins and breccias are often the products of hydrofractures that are left in the geological record, we discuss these and critically assess which vein structures can, and which do not necessarily, indicate hydrofracturing. Hydrofracturing can suddenly and locally change the permeability in a rock by providing new fluid pathways. This can lead to highly dynamic self-organization of crustal-scale fluid flow.

Exploiting Multiperspective Driven Hierarchical Content-Aware Network for Finger Vein Verification

The finger vein trait has attracted widespread attention for personal authentication in recent years. However, most finger vein verification methods are performed on the single perspective, captured by a monocular near-infrared camera fixed at one side of the finger. Consequently, the contents of a single perspective have few details of the spatial network structure of the finger vein and show noticeable differences even if the posture of the same finger is slightly different. Both of them impact the verification performance. Hence, finger vein images captured from different viewpoints are considered in this work. We first design a low-cost multi-perspective based dorsal finger vein imaging device for data collection. A deep neural network named Hierarchical Content-Aware Network (HCAN) is then proposed to extract the discriminative hierarchical features of the finger vein. Specifically, HCAN is compound of a Global Stem Network (GSN) and a Local Perception Module (LPM). GSN aims to extract the latent global 3D feature from all perspectives through a recurrent neural network. It enables the model to retain the details in previous hidden states by incorporating a memory weighting strategy. LPM is designed to perceive each perspective from the aspect of image entropy. Guided by the entropy loss, LPM captures the prominent local feature and improves the discriminability and robustness of the hierarchical feature. The experimental results on the newly collected THU-MFV database demonstrate the superiority of the proposed method in comparison with other multi-perspective and single-perspective based methods.

RELATIONSHIP BETWEEN ULTRASOUND CHANGES IN THE LIVER AND HYPOTHYROIDISM IN PATIENTS WITH AUTOIMMUNE THYROIDITIS

Hashimoto's autoimmune thyroiditis (AIT) is one of the most frequent causes of hypothyroidism, which leads to the development of dysfunctions of various body systems. Since the hepatobiliary system is closely related to the thyroid gland, a decrease in thyroid function is considered one of the factors in the development of non-alcoholic fatty liver disease. Early detection of changes in the liver in patients with hypothyroidism makes it possible to start therapy in time and prevent the development of complications, such as fatty dystrophy, inflammation, damage to hepatocytes, fibrosis, cirrhosis.&#x0D; The aim. Determine the relationship between hypothyroidism and ultrasound changes in the liver in patients with AIT.&#x0D; Methods. 62 patients with AIT and hypothyroidism were examined. The first group included 32 patients with a history of AIT up to two years, the second group included 30 patients with a history of the disease for more than two years, and the control group included 30 patients without signs of thyroid pathology. Thyroid function was assessed based on the results of a hormone levels blood test. Multiparametric ultrasound examination of the liver and thyroid gland was performed on Siemens Acuson S2000 and S3000 devices in B-mode, color doppler mapping, pulse-wave doppler and shear-wave elastography (SWE) modes.&#x0D; Results. Ultrasound changes in the liver were more often observed in patients with subclinical hypothyroidism on the background of AIT. It was found that the number of patients with sonographic signs of liver damage is greater in the second group than in the first. Sonographic signs of the hepatobiliary system damage included an increase in the size of the liver, an increase in the echogenicity of its parenchyma, not homogeneous structure and dilatation of the portal vein.&#x0D; The analysis of the level of shear wave speed in the parenchyma of the thyroid gland showed that it was higher in second groups and its increase was also noted in patients with subclinical and clinical hypothyroidism.&#x0D; The results of SWE of the liver demonstrated a positive correlation between the stiffness of the liver parenchyma and the duration of AIT. Also, significantly higher values of SWE were observed in patients who, at the time of examination, had laboratory signs of thyroid dysfunction and the high level of shear wave velocity in the thyroid gland parenchyma. The analysis of the number of cases of liver fibrosis in two groups showed that it is more often detected during the long course of the disease. The percentage of patients with F1-F2 in the first group was 32% and in the second group - 53%.&#x0D; Conclusions. The established relationship between sonographic signs of diffuse changes in the liver parenchyma and hypothyroidism determines the expediency of using multiparametric ultrasound examination of the hepatobiliary system in patients with AIT to assess its condition, early diagnosis of fibrosis and determine the need for correction of treatment tactics.

Vein-Based Coalitions for Multi-Agent Pattern Formation Tasks

This letter explores the vein trait of the structural formation task and extracts four typical parallel-straight vein structures for generating coalitions. Then, the Vein-Based Multi-Agent Pattern Formation (VB-MAPF) method is proposed to resolve task and path planning on coalitions. Besides, the presented rectifying operation guarantees the optimal coalition structure, and the vein-based pruned conflict-based search reduces the searching space for collision-free path planning. Compared with typical solvers, the inter-performance and the intra-performance orders show the efficiency and scalability of the VB-MAPF method in terms of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">makespan</i> , <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">average distance</i> , and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">maximum distance</i> on dozens of coalitions and thousands of agents.

Enhancing Rubisco gene expression and metabolites accumulation for better plant growth in Ficus deltoidea under drought stress using hydrogen peroxide.

Growth improvement of the medicinal plant, Ficus deltoidea (Mas Cotek) under drought conditions is a vital issue in Malaysia since it is a slow-growing plant and disposed to leaf damage under the stresses of drought. Therefore, investigation was done to examine the outcomes of hydrogen peroxide (H2O2) application on Rubisco gene expression and metabolites accumulation of stressed F. deltoidea plants, and thereby to record the changes in leaf histology, photosynthesis, biochemical properties, and the growth of the plant. H2O2 at the rates of 0, 5, 10, 15, and 20 mM were foliar sprayed biweekly on the drought stressed plants using a hand sprayer. The application of 20 mM H2O2 amplified leaf number, tallness, stomatal conductance, and photosynthetic yield by 143, 24, 88, and 18%, respectively, over the control plant. A reduced transpiration rate and improved chlorophyll fluorescence were also noted in H2O2-treated plants. The treatment produced a greater amount of chlorophyll a, total phenols, total flavonoids, sugar content, and antioxidant activities by 1.61-, 1.30-, 1.98-, 1.92-, and 1.53-fold, respectively. Application of 15 mM H2O2 enhanced net photosynthetic rate and internal CO2 concentrations by 1.05- and 1.25-fold, respectively. Additionally, H2O2 treatments promoted stomatal closure, increased stomata size, the number of stomata, improved vein structure, and reduced the damage of the leaf margin and mesophyll cells of drought stressed plants. The application of H2O2 also accumulated significantly higher contents of sodium (Na+), calcium (Ca2+), potassium (K+), magnesium (Mg+), and iron (Fe2+) in stressed plants. Although the amount of Arsenic (As+) and Antimony (Sb3+) increased to some extent, the increases were not at a toxic level. The use of H2O2 enhanced the Rubisco gene expression to a greater level and the ratio of Rubisco expression increased up to 16-fold. Finally, thirteen (13) identified and five (5) unmatched volatile compounds with a quality score above 70% were identified by gas chromatography-mass spectrometry (GCMS). The GCMS analysis showed that the foliar application of H2O2 accumulates a higher percentage of volatile components in plants which helps to mitigate the negative effects of drought stress. It is concluded that under drought stressed conditions the F. deltoidea plants should be treated with 10–15 mM of H2O2 twice a week to improve leaf histology, photosynthesis, the level of Rubisco gene expression and volatile compounds accumulation, and plant growth and development.

Influence of the Anatomical Structure on the Hemodynamics of Iliac Vein Stenosis.

Few reports study the effects of the anatomical structure of the iliac vein on hemodynamics and the methods to reduce and delay in-stent thrombosis. The anatomical structure of iliac vein stenosis was used to establish vascular models with different stenosis rates, taper angle, and left branch tilt angle in the work. The influence of anatomical structure on hemodynamics was revealed through theoretical research and in vitro experimental verification. A real iliac vein model was built based on computed tomography angiography (CTA) images, and hemorheological parameters including time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI) and relative residence time (RRT) were analyzed by computational fluid dynamics (CFD). The results showed that iliac vein stenosis could significantly increase the wall shear stress (WSS) of the blood vessels at the stenosis site and outside the intersection area, which was easy to produce eddy currents in the distal blood vessels. With the increased taper angle, the proportion of low-wall shear stress areas and the risk of thrombosis increased. A small tilt angle could aggravate the influence of narrow blood vessels on the blood flow characteristics and vascular wall. The numerical simulation results were consistent with the theoretical research results, and the experimental study verified the correctness of the simulation. The work is helpful to further understand the hemodynamic characteristics of the iliac vein, providing a scientific reference for clinical treatment and diagnosis.

Provenance Tracing and Age Analysis of Lead–Zinc Mineralization in Qiyimuchang, Inner Mongolia, NE China

The Qiyimuchang lead–zinc deposit is an important deposit in the Erguna Massif on the west slope of Daxinganling, for which the material source and age of mineralization remain unclear. The lead–zinc deposit in Qiyimuchang has been observed to occur in Jurassic volcanic strata as a vein-like orebody, and its strike is nearly perpendicular to that of the strata and the regional structures of the orogenic belt. The ore is mainly composed of sphalerite, galena, chalcopyrite, pyrite, and quartz, and hydrothermal alteration zones dominated by silicification, fluoritization, and pyritization are common within 1–5 m on both sides of the vein. The metasomatic lead–zinc mineralization is characterized by a massive vein structure. The mineralization process can be divided into three stages, pre-ore (mainly quartz, arsenopyrite and a small amount of pyrite), ore-formation (pyrite, chalcopyrite, sphalerite, galena, fluorite, and a small amount of tetrahedrite), and post-ore (quartz-calcite veinlets with a small amount of pyrite). Element and isotope geochemical studies show that the trace element compositions of the wall rocks (andesite, tuff, etc.) of Jurassic volcanic rocks in the ore bodies and surrounding rocks reflect affinity or similarity between them. The S isotopic composition of sulfide minerals in the metallogenic stage (δ 34SV-CDT = 1.6‰~4.8‰) indicate the sulfur isotopic composition of the magma. The Pb isotopic compositions of sulfide minerals (38.5–38.39, 15.55–15.62, and 18.33–18.41 for 208Pb/204Pb, 207Pb/204Pb, and 206Pb/204Pb, respectively) in the metallogenic stage are relatively concentrated and close to the average Pb isotopic compositions of the mantle and average Pb isotopic composition of an orogenic belt, indicating that the ore-forming metals are likely to be a mixed source of crust and mantle. A new zircon U-Pb age of 150.8 ± 1.3 Ma (MSWD = 0.74) was obtained from andesitic tuff. Collectively considering the regional geology and ore deposit geological analysis, the lead–zinc mineralization in Qiyimuchang possibly occurred during the early Cretaceous. The ore-forming processes belong to Cretaceous magmatic-hydrothermal activity in extensional tectonic setting.

On the cyclic hardening/softening behavior of a rare earth-containing magnesium alloy during strain-controlled fatigue

The origin of cyclic hardening under low strain amplitude (with N = 25284 cycles to failure) followed by pseudo-plateau response under high strain amplitude (with N = 2671 cycles to failure) during fully reversal (R = −1) strain-controlled pull–push fatigue of Mg-8.2Gd-3.6Y-1.6Zn-0.5Zr (wt.%) at room temperature condition was explored. The (i) dislocations trapping between LPSO (long period stacking order) lamellas, (ii) substructure development, and (iii) deformation twinning and tangling/rearrangement of partials within twin band were known as the main factors contributing to the room temperature cyclic hardening response. The pseudo-plateau behavior and cyclic stabilization were also attributed to the co-formation of the veins structure in the vicinity of 18R LPSO and reversion of 14H LPSO at higher strain amplitudes.

Convenient design method for customized implants based on bionic vein structure features.

Matching implants to bones is crucial for customized orthopedic medicine. Existing methods for designing customized implants predominantly adopt the parameterized deformation method that uses a fragmented representation of semantic parameters. Such a representation cannot provide information integration management and therefore restricts the retrieval of information regarding implant features and the improvement of customized design efficiency. Therefore, this study proposes a rapid design method for customized implants based on bionic vein structure features. First, a bionic vein structure was designed to represent the implant type. Second, the bionic vein structure was represented by a digraph structure with morphological and dimensional features. Finally, the implant model was rapidly built by retrieving the sketch and other modeling operations. Common implants such as the T-shaped plate, L-shaped plate, clover plate, and femoral stem prosthesis were used as explanations or test cases. The experimental work shows that combining the traditional parametric deformation method with bionic vein structure features in our present method is flexible and efficient results, and can improve the efficiency of customized implant design.

Influence of cutting through the middle vein of tobacco leaves on the technological properties of raw materials of the Virginia 202 variety of various drying methods

The Virginia 202 tobacco variety, selected by FSBSI ARSRITMTP for the production of smoking tobacco, is in high demand. Intensification of post-harvest processing of large leaves of a variety with a massive middle vein is proposed to be carried out by cutting through the middle vein, which will reduce the drying time and energy costs. Studies have been conducted on the use of this method and the quality indicators of tobacco raw materials of natural and combined drying methods has been assessed. It has been found that the cutting technique shortens the drying time with the combined method by 2.8 times, with the natural method by 2.3 times, while the commercial quality improves when drying by the combined method, the yield of 1 commercial grade makes 86.5%, the taste qualities of raw materials improve, due to an increase in the ratio of carbohydrate-protein balance to 1.08–1.5; the strength is preserved, due to less nicotine consumption during a shorter drying period; fiber yield increases by 3–5%. The volume-elastic properties of the fiber affect the consumption of raw materials in the smoking product. The fiber of natural drying of raw materials reduces its consumption for the production of smoking products, the fiber of combined drying of raw materials obtained using high temperatures of drying of the vein increases the consumption of raw materials by 18.65%. The aim of the research is to determine the elastic properties of the cut vein present in the fiber of combined drying. The vein has been flattened and its elastic properties have been determined. It has been established that the recoil value of the flattened uncut vein is 6.0% greater, the undisturbed structure of the middle vein has a greater degree of volume recovery and better elastic properties. An increase in the elastic properties of the raw materials of combined drying can be carried out due to its preparation in a differentiated way, with the allocation of the middle vein, the method of striping and, separately, the preparation of the vein and the leaf plate. When preparing, moistening and flattening the cut vein, which has a better moisture-absorbing ability and a lower destructive load when it is flattened by 2.2 times, it is possible to reduce energy consumption for these technological processes.