Internal Structural Features Research Articles

Особенности дефектно-примесного состава кристаллов алмаза с пирамидами роста <100> из россыпей Красновишерского района, Урал

The internal structure of cuboid diamonds from contemporary alluvial placers of the Krasnovishersky district at the Urals was investigated with analyzing their spectroscopic characteristics. Crystals were divided into four groups by their anatomy and spectroscopic features: cuboids of the II variety in the Yu. L. Orlov classification; cuboids with transparent core and outer part saturated with inclusions; crystals with simultaneous growth of and pyramids, and crystals with their consecutive growth. The local photoluminescence investigations have been carried out for all different growth zones and pyramids. There was revealed localization of luminescence bands 926 and 933 nm to growth pyramids and . In all studied crystals, the last stage of growth was the regenerative formation of {111} face steps together with square pits forming on the surface. Some cuboids with C centres have specific luminescence systems, such as 575, 635.1, 636.8 nm, broad band with maximum at 700 nm, and intense lines at 800, 820.5, 840, 860, 869 nm. Different thermal history of mixed-habit diamonds was shown. It is noted that the cuboid diamonds from different regions of the world have the similar internal structure and spectroscopic features.

Study on Multi-Point Random Contact Characteristics of Metal Rubber Spiral Mesh Structure

Metal rubber (MR) is a porous damping material, which achieves the damping energy consumption by the contact friction between the internal wires. Complex wire structure makes explanation of energy dissipation mechanism by the traditional theoretical models limited to comparison with equivalent models or microcell models, which cannot truly reflect the spatial multi-point contact characteristics of each wire. This work demonstrates numerical modeling based on actual preparation process parameters of annular MR. Using the penalty function to solve the complex contact that is difficult to predict between the internal spiral wires, the variation laws for equivalent stress and strain recorded during the loading-unloading process of MR, were obtained. The small-ball algorithm and the Tabu search algorithm were used to realize the accurate assessment of contact points between the wires and the hyper dimension matrix was used to track the friction state of the contact points in real time, thereby obtaining a proportional relationship between various friction forms during the loading-unloading process. It is found that sliding friction accounts for the majority of the total number of contact points, which is about 81.38%, consistent with the equivalent plastic strain law of stepwise change. It becomes further clarified from the microscopic point that MR accomplishes macroscopic energy dissipation mechanism through the fretting slip friction between the internal wires. In order to verify the authenticity of the simulation, a quasi-static loading-unloading experiment of MR was carried out under identical parameters, and the experimental macroscopic results were in excellent agreement with the simulation results. The research indicates that the MR finite element model established in this paper can precisely describe the dynamic contact of the internal structural features of MR materials, for providing a theoretical basis for guiding the preparation and application of MR.

The Analysis of Xylem Vessel Structure of Populus euphratica Oliv.Fresh Branch by HRCT

ABSTRACTAnalysis of the xylem vessels of Populus euphratica Oliv. (P. euphratica) branch anatomical characteristics is usually performed using microtomy. It is time-consuming to obtain an abundance of cross-sections using microtomy, and the sample was dried and sliced. The more effective technology for the analysis of the anatomical characteristics of P. euphratica fresh branch would be of significance for the study of the tolerance mechanism. In this paper, the xylem vessels structure of P. euphratica branches were investigated by high-resolution computed tomography(HRCT) and scanning electron microscope (SEM) to establish an efficient method to research the tolerance mechanism of P. euphratica. Analysis of the images allowed characterisation of the internal morphological and histology structural features of the fresh and dried branches of P. euphratica. Drying process caused distinct changes in the microstructure of the branches with shrinking in the more external regions and the interspace between vessels compared with fresh branches. The SEM slice of the same sample that clearly has a higher resolution than the HRCT slice, and the structure of the xylem vessels is distinct in the SEM. However, SEM is a destructive process that requires complex sample preparation, and the quality of the sample preparation and staining directly affect the resulting images. It can be concluded that the xylem vessel of P. euphratica branches can be observed using HRCT, which offers an effective means of obtaining the needed quantitative data on the tolerance mechanism of P. euphratica.

Physiological and anatomical studies of two wheat cultivars irrigated with magnetic water under drought stress conditions

The aim of this study was to assess some physiological parameters and anatomical changes in two wheat plant cultivars (Triticum aestivum L. cvs. Sakha 93 and Sids 9) in response to irrigation with magnetized water under two levels of drought stress (field capacity (FC) of 75% and 50%) and the control (FC 100%) in two consecutive winter growing seasons (November 20 to May 5 2014/2015 and 2015/2016). Pot experiments were carried out in a greenhouse in the experimental farm of the Faculty of Agriculture, Menoufia University, Shibin El-Kom, Egypt. A water deficit, particularly at 50% FC, significantly decreased growth and parameter values, above all in Sakha 93, and disrupted most physiological aspects, biochemical constituents and internal structural features of both wheat cultivars. Irrigation with magnetized water alleviated the negative consequences of drought stress on most physiological and biochemical parameters to a variable extent: the whole plant dry weight, total water content, total soluble sugar concentration in leaves, total free amino acids and proline increased by about 32, 12, 17, 27 and 73%, respectively, under 50% FC drought stress in Sids 9 compared to the control. As the levels of drought increased, the grain yield (g/plant) decreased considerably, from about 81% in Sakha 93 at 50% FC to 26% in Sids 9 at 75% FC. The use of magnetic water increased grain yield from 61% in Sakha 93 at 75% FC to about 268% in Sids 9 at 50% FC. Magnetic water also increased the thickness of the flag leaf midvein and lamina, as well as the metaxylem vessel diameter of Sakha 93 by 28.8, 11.7 and 20.0%, respectively, compared to the control. The application of magnetic water increased the growth and the other parameter values studied in both cultivars but above all in Sakha 93, whereas Sids 9 produced more grain yield under all levels of drought stress. As the growth and grain production increased in both cultivars when using magnetic water, this study recommends this type of irrigation for these wheat plants, which are widespread in Egypt.

Is a Nervous System Necessary for Learning?

In this article, I propose some elements for a conceptual foundation for a negative answer to the titular question, based on a historical conceptual analysis of some definitions of "learning" in the specialized literature. I intend such a foundation to include learning in living organisms as well as inorganic machines. After analyzing several behavioral and nonbehavioral definitions, I argue that although most of the former favor a negative answer, they tend to be restricted to living organisms and thus exclude inorganic machine learning. They also face the yet-unresolved issue of behavioral silence, which makes behavior not defining of learning. Some nonbehavioral neurobiological definitions favor an affirmative, others a negative answer, but still exclude inorganic machines. Nonneurobiological definitions are more suitable, but they commit us to some form of computationalism (Turing machine or connectionist) about learning, which is premature. I thus propose elements for an alternative definition of "learning" without such commitment. The elements are elaborations of the notions of learning as a kind of causal interaction between causal stochastic environmental and internal processes, and minimal learner as a kind of abstract system that shares certain internal structural and functional features with animals, spinal vertebrates, bacteria, plants, and inorganic machines.

Amyloid Pan-inhibitors: One Family of Compounds To Cope with All Conformational Diseases.

Amyloids are ubiquitous protein aggregates sharing common internal structural features; they are present in all organisms, from prokaryotes to eukaryotes, where they play physiological or pathological roles. Importantly, amyloids, which are generated by aggregation of a range of distinct proteins, could be a key factor in a number of major human disorders, the so-called conformational diseases. Because all amyloids exhibit similar cross-β motifs, one may envisage that molecules capable of blocking the formation of β-sheet structures could abolish aggregation of all amyloid proteins, albeit with different efficacies. Herein, two different β-sheet blockers were tested against a selection of amyloidogenic proteins, encompassing all the major types of amyloid-based disorders. Analysis of their blocking efficiency, using a simple but contrasted cell-based screening procedure, unequivocally confirms that they indeed behave as aggregation pan-inhibitors. The significant inhibitory effects observed for these compounds against all tested amyloidogenic proteins could spur a broader biological evaluation of other known and new amyloid aggregation inhibitors to further determine the potential use of this class of compounds for the universal treatment of conformational diseases.

3D shape classification and retrieval based on polar view

This paper presents a novel approach for classifying and retrieving 3D shapes. We first propose a new polar view based strategy that, by using 360-degree projection, effectively reflects the internal structure and key features of a 3D shape. Specifically, the point cloud of the 3D shape is mapped to a two-dimensional (2D) plane, and the polar view representation is obtained by the maximum depth of the point cloud. Projecting 3D point clouds into a 2D plane enables us to use sufficient image data for training, and the process also takes advantage of both image-based and 3D shape-based methods. We propose a convolutional neural network (CNN) that is trained by using only a single polar view of a 3D shape to obtain the polar view representation (PVR) and realize the classification and retrieval of 3D shapes. Experiments on standard datasets, such as ModelNet10 and ModelNet40, show that our method outperforms state-of-the-art methods on 3D shape classification and retrieval.

Ultrathin Fresnel lens based on plasmene nanosheets

Ultrathin Fresnel lens may revolutionize current optical imaging system, leading to thinner and lighter optoelectronic devices with a myriad of technical applications. To date, evaporated bulk metal films and top-down grown graphene represent viable material choices toward the design of ultrathin Fresnel lenses. Despite recent advances, it is still lack of a scalable fabrication strategy to achieve ultrathin lens with high focusing efficiency. Here, we report a new self-assembled metamaterials-based strategy to design ultrathin Fresnel lens using our recently reported plasmene nanosheets. With comparable thickness, our plasmene-based Fresnel lens offers a much better focusing efficiency than that based on continuous metallic films. This may be attributed to the dual Huygens’ effects from both slits and plasmene-constituent nanoparticle building blocks. Importantly, internal structural features of plasmene can be precisely tuned simply by adjusting sizes and shapes of its constituent building blocks, allowing for maximizing the focusing efficiency at a desired operating wavelength – a capability impossible to achieve with continuous metal films or graphene. Our plasmene-based strategy opens a new route to design tailor-made flat lens with finely tunable internal and overall structural properties, which offers new dimensionalities in controlling light-matter interactions for a myriad of technological applications.

Dislocation etching of diamond crystals grown in Mg-C system with the addition of silicon

The dislocation structure of diamond crystals grown in the Mg-Si-C system at pressure of 7.0–7.5 GPa and temperature of 1800 °C was studied by selective etching. We determined the dislocation density and identified individual features of etching for the growth sectors of {111} and {100} faces. On the {111} faces, all etch pits formed at the outcrops of different dislocations were found to be identical. The feature of grown diamond crystals is the presence of numerous large dislocation loops in the {100} growth sectors. The identified patterns of crystals etching and the internal crystal structure features are associated with the presence of a silicon impurity in the grown diamonds.

Internal Structure Features of Asphalt Mixture for Field Samples

Asphalt mixture is heterogeneous in nature; consequently, macroscopic parameters alone cannot describe the mechanical behavior of the mixture. In recent years, the arrangement of the aggregate particles in terms of spatial and directional distributions, and contact points are contemplated as the internal structure of asphalt. The main purpose of this article is to examine the microstructural characteristics of asphalt cores applying 2-D images. Comparison between the internal structure features in the laboratory samples and the Field samples is indicated in this paper. The results reveal that the survey of microstructural characteristics of asphalt cores by image processing provides new and functional information. This finding indicates that the number of contact points in cores is close to the lab samples that have been made at 45 to 65 blows on each end of the sample.

Chemically Active, Porous 3D-Printed Thermoplastic Composites.

Metal-organic frameworks (MOFs) exhibit exceptional properties and are widely investigated because of their structural and functional versatility relevant to catalysis, separations, and sensing applications. However, their commercial or large-scale application is often limited by their powder forms which make integration into devices challenging. Here, we report the production of MOF-thermoplastic polymer composites in well-defined and customizable forms and with complex internal structural features accessed via a standard three-dimensional (3D) printer. MOFs (zeolitic imidazolate framework; ZIF-8) were incorporated homogeneously into both poly(lactic acid) (PLA) and thermoplastic polyurethane (TPU) matrices at high loadings (up to 50% by mass), extruded into filaments, and utilized for on-demand access to 3D structures by fused deposition modeling. Printed, rigid PLA/MOF composites display a large surface area (SAavg = 531 m2 g-1) and hierarchical pore features, whereas flexible TPU/MOF composites achieve a high surface area (SAavg = 706 m2 g-1) by employing a simple method developed to expose obstructed micropores postprinting. Critically, embedded particles in the plastic matrices retain their ability to participate in chemical interactions characteristic of the parent framework. The fabrication strategies were extended to other MOFs and illustrate the potential of 3D printing to create unique porous and high surface area chemically active structures.

Calcite production by the calcifying green alga Phacotus lenticularis

The importance of carbonate precipitation by phytoplankton in fresh water lakes has not been sufficiently considered in global carbon cycles and climate change scenarios. The objective of this study was to determine the influence of the calcifying bivalved phytoflagellate Phacotus lenticularis (Ehrenberg) Deising 1866 on the total calcite precipitation in five European hard-water lakes. For this purpose, an accurate mass determination of single Phacotus lenticularis shells was required. We developed a novel methodological approach to precisely determine the volume and mass of the calcified shells. Focused ion beam (FIB) techniques were employed to investigate internal structural features. Thin layer cross-sections of the shell profiles were reproduced and perforation as well as the crystalline structure of the calcite plates were monitored. 3D-shell models were computed by 360° rotation of the shell cross-sections using a CAD 3D imaging software to calculate precise volumes and estimate realistic masses. In contrast to previous estimates, we determined a 2.8-fold higher shell mass of 0.86 ng CaCO3 (standard deviation SD = 0.18) for the highly massive shells at a mean volume per individual of 334.1 µm³ (SD = 70). An initial shell porosity of less than 5% was derived from thin layer cross-section images, resulting in a presumed mean shell density of 0.0026 ng µm−3. The shell diameter was significantly influenced by the lake’s origin. The shells from each lake displayed substantial variations in diameter and shape. The pores in the shells showed two variations. Wider pore canals penetrated the whole shell wall, whereas small, elongated pores were located along the interspaces between calcite crystals with tabular habit. The approximate average dimensions of these calcite plates were 1.0 × 1.6 × 0.2 µm. The mean lateral wall thickness at the rim and centre of the shell were 1.98 µm (SD = 0.42) and 0.79 µm (SD = 0.17), respectively. The average carbonate precipitation by Phacotus lenticularis in relation to the total epilimnetic suspended calcite precipitation was 6.0% in the oligotrophic lake Großer Ostersee (Bavaria, Germany). During the growing season, Phacotus lenticularis contributed up to 21% of the particulate calcium carbonate in the epilimnion. These findings suggest that Phacotus lenticularis should be considered in the assessment of hard-water lake carbon cycling.

A Comparative Study of Technologies Developed in Perspective of Distributed Operating Systems

The collection of processors that do not share memory and clock is called distributed operating system. It is an infrastructure which is programmed so that it allows the use of multiple workstations as a single integrated system. In distributed OS users can access remote resources as they access local ones. The advantages of distributed operating systems are performance through parallelism, reliability and availability through replication and in addition scalability, expansion and flexibility of resources. This research paper includes a detailed and comparative introduction of different state-of-art technologies and operating systems, their internal structure, design and key features which are developed in perspective of distributed operating systems. These operating systems includes Chorus, V-systems, Amoeba and Mach.

The Filtration Equation for Packing Material

The criterial equation summarizing experimental data on filtration through packing of various structure was proposed in this study. The equation does not depend on the internal structure and construction features of the packing pieces.

Towards a Holistic Cortical Thickness Descriptor: Heat Kernel-Based Grey Matter Morphology Signatures

In this paper, we propose a heat kernel based regional shape descriptor that may be capable of better exploiting volumetric morphological information than other available methods, thereby improving statistical power on brain magnetic resonance imaging (MRI) analysis. The mechanism of our analysis is driven by the graph spectrum and the heat kernel theory, to capture the volumetric geometry information in the constructed tetrahedral meshes. In order to capture profound brain grey matter shape changes, we first use the volumetric Laplace-Beltrami operator to determine the point pair correspondence between white-grey matter and CSF-grey matter boundary surfaces by computing the streamlines in a tetrahedral mesh. Secondly, we propose multi-scale grey matter morphology signatures to describe the transition probability by random walk between the point pairs, which reflects the inherent geometric characteristics. Thirdly, a point distribution model is applied to reduce the dimensionality of the grey matter morphology signatures and generate the internal structure features. With the sparse linear discriminant analysis, we select a concise morphology feature set with improved classification accuracies. In our experiments, the proposed work outperformed the cortical thickness features computed by FreeSurfer software in the classification of Alzheimer's disease and its prodromal stage, i.e., mild cognitive impairment, on publicly available data from the Alzheimer's Disease Neuroimaging Initiative. The multi-scale and physics based volumetric structure feature may bring stronger statistical power than some traditional methods for MRI-based grey matter morphology analysis.

In-Process Monitoring of Selective Laser Melting: Spatial Detection of Defects Via Image Data Analysis

Selective laser melting (SLM) has been attracting a growing interest in different industrial sectors as it is one of the key technologies for metal additive manufacturing (AM). Despite the relevant improvements made by the SLM technology in the recent years, process capability is still a major issue for its industrial breakthrough. As a matter of fact, different kinds of defect may originate during the layerwise process. In some cases, they propagate from one layer to the following ones leading to a job failure. In other cases, they are hardly visible and detectable by inspecting the final part, as they can affect the internal structure or structural features that are difficult to measure. This implies the need for in-process monitoring methods able to rapidly detect and locate defect onsets during the process itself. Different authors have been investigating machine sensorization architectures, but the development of statistical monitoring techniques is still in a very preliminary phase. This paper proposes a method for the detection and spatial identification of defects during the layerwise process by using a machine vision system in the visible range. A statistical descriptor based on principal component analysis (PCA) applied to image data is presented, which is suitable to identify defective areas of a layer. The use of image k-means clustering analysis is then proposed for automated defect detection. A real case study in SLM including both simple and complicated geometries is discussed to demonstrate the performances of the method.

Integrated Information and Prospects for Gliding Mechanism of the Pathogenic Bacterium Mycoplasma pneumoniae.

Mycoplasma pneumoniae forms a membrane protrusion at a cell pole and is known to adhere to solid surfaces, including animal cells, and can glide on these surfaces with a speed up to 1 μm per second. Notably, gliding appears to be involved in the infectious process in addition to providing the bacteria with a means of escaping the host's immune systems. However, the genome of M. pneumoniae does not encode any of the known genes found in other bacterial motility systems or any conventional motor proteins that are responsible for eukaryotic motility. Thus, further analysis of the mechanism underlying M. pneumoniae gliding is warranted. The gliding machinery formed as the membrane protrusion can be divided into the surface and internal structures. On the surface, P1 adhesin, a 170 kDa transmembrane protein forms an adhesin complex with other two proteins. The internal structure features a terminal button, paired plates, and a bowl (wheel) complex. In total, the organelle is composed of more than 15 proteins. By integrating the currently available information by genetics, microscopy, and structural analyses, we have suggested a working model for the architecture of the organelle. Furthermore, in this article, we suggest and discuss a possible mechanism of gliding based on the structural model, in which the force generated around the bowl complex transmits through the paired plates, reaching the adhesin complex, resulting in the repeated catch of sialylated oligosaccharides on the host surface by the adhesin complex.

Characterization of automotive paint by optical coherence tomography

Automotive paint is common trace evidence that plays a significant role in many vehicle-related criminal cases. However, the conventional methods of obtaining tomographic images tend to damage the samples. Optical coherence tomography (OCT) is a novel method to obtain high-resolution and cross-sectional images of the automotive paints in a non-destructive, and high-speed manner. In this study, OCT was applied to image and analyze the automotive paint, using scanning electron microscope (SEM) as reference. Eight automotive paint samples of different brands were examined. The images of multi-layer structures provided by OCT system with 5μm depth resolution were consistent with those by SEM. To distinguish different paints with similar visual appearance, we extracted internal structural features from the images using peak analysis and optical attenuation fit. Six characterized parameters were found to distinguish the samples including the optical path length (OPL) of base coat, the optical attenuation coefficient (OAC) of base coat, the OPL of clear coat, the back-scattering ratio (BSR) of clear coat and base coat, the OPL of primer surfacer, and the BSR of base coat and primer. Statistical differences were evaluated by an independent t-test with p<0.05. OCT was applied to analyze repainted paint as well. Three-dimensional OCT reconstruction of the paints was also implemented to create en face (transverse section) images for morphology examination and comparison. These results suggest that OCT imaging can provide additional new features for analyzing the automotive paints and thereby may be a promising supplement to traditional methods. Meanwhile, the OCT system is favorable for achieving in-situ and real-time examination at the scene of crime.

Using non-invasive molecular spectroscopic techniques to detect unique aspects of protein Amide functional groups and chemical properties of modeled forage from different sourced-origins

The non-invasive molecular spectroscopic technique-FT/IR is capable to detect the molecular structure spectral features that are associated with biological, nutritional and biodegradation functions. However, to date, few researches have been conducted to use these non-invasive molecular spectroscopic techniques to study forage internal protein structures associated with biodegradation and biological functions. The objectives of this study were to detect unique aspects and association of protein Amide functional groups in terms of protein Amide I and II spectral profiles and chemical properties in the alfalfa forage (Medicago sativa L.) from different sourced-origins. In this study, alfalfa hay with two different origins was used as modeled forage for molecular structure and chemical property study. In each forage origin, five to seven sources were analyzed. The molecular spectral profiles were determined using FT/IR non-invasive molecular spectroscopy. The parameters of protein spectral profiles included functional groups of Amide I, Amide II and Amide I to II ratio. The results show that the modeled forage Amide I and Amide II were centered at 1653cm−1 and 1545cm−1, respectively. The Amide I spectral height and area intensities were from 0.02 to 0.03 and 2.67 to 3.36 AI, respectively. The Amide II spectral height and area intensities were from 0.01 to 0.02 and 0.71 to 0.93 AI, respectively. The Amide I to II spectral peak height and area ratios were from 1.86 to 1.88 and 3.68 to 3.79, respectively. Our results show that the non-invasive molecular spectroscopic techniques are capable to detect forage internal protein structure features which are associated with forage chemical properties.

Evaluation of Filtering Bleb Function after Trabeculectomy with Mitomycin C Using Biomicroscopy, Anterior Segment Optical Coherence Tomography and In Vivo Confocal Microscopy.

Objectives:To analyze and assess compatibility of trabeculectomy filtering bleb characteristics and appearances using biomicroscopy, anterior segment optical coherence tomography (AS-OCT) and in vivo confocal microscopy (IVCM).Materials and Methods:Twenty-eight eyes of 28 patients who underwent glaucoma filtering surgery with mitomycin C in our clinic between 2009 and 2013 were evaluated. Morphological appearances of the blebs on slit-lamp biomicroscopy were defined according to the Moorfields bleb classification system. For the internal tissue assessment of blebs, AS-OCT and IVCM were performed. Bleb biometric parameters such as length, height and bleb wall thickness were assessed by AS-OCT; conjunctival epithelial-stromal cyst, structural network of conjunctival stroma and vascularisation were examined with IVCM. The relation between biomicroscopic morphological staging and bleb characteristics detected on AS-OCT and IVCM were assessed.Results:The mean age of the 28 patients (16 male, 12 female) was 57.2±15.9 (19 to 79) years. The mean time elapsed between surgery and examination was 29.2±19.2 (6 to 68) months. According to biomicroscopic appearance, 17 (60.7%) blebs were functional (13 diffuse, 4 microcystic), whereas 11 (39.3%) blebs were non-functional (9 flat, 2 encapsulated). In the comparison of non-functional and functional blebs, functional blebs were found to be superior in terms of biometric parameters on AS-OCT assessment (p<0.05). Higher number of epithelial and stromal cysts and less vascularisation were detected by IVCM in functional blebs when compared with non-functional blebs (p<0.05).Conclusion:Biomicroscopic appearances and characteristics on AS-OCT and IVCM of filtration blebs are consistent with each other. Besides biomicroscopic examination, which is an easy and practical method for determining bleb morphology, cross-sectional images obtained by AS-OCT and IVCM provide objective data regarding internal structure and functional features of blebs.