Tridimensional Representation Research Articles

Measuring Distances and Areas under Forest Canopy Conditions—A Comparison of Handheld Mobile Laser Scanner and Handheld Global Navigation Satellite System

Measuring distances and areas under forest canopy conditions is often required for a broad range of forest research and management-related activities. While modern technologies, such as handheld mobile laser scanning (MLS), made possible the tridimensional representation of forests with great accuracy, the practical application is still limited by its high costs and challenging data processing. The handheld Global Navigation Satellite System (GNSS) represents the classical alternative, determining the distances and areas based on point coordinates. In this study, we aimed to assess the accuracy of a handheld GNSS, relative to the handheld MLS, in measuring distances and areas under forest canopy conditions. The material consists of 209 ant nests, which were mapped in a mixed-species deciduous forest of North-Eastern Romania. The GNSS- and MLS-based distances among nests were compared using the Bland–Altman plots. The differences in size and shape of the areas described by the nests were analyzed using (i) the shape compactness and (ii) the form factor of the convex polygons. In general, the GNSS-based distances were shorter compared with those based on MLS. However, for most cases, the intervals of agreement between the two instruments were within the limits of GNSS accuracy (i.e., ±10 m). The largest mean differences occurred when nests were in dense canopy conditions and on rugged terrain. The GNSS-based area of the convex polygons was smaller in most cases, but no significant correlation between the size of the area and the size of the relative difference was found. Furthermore, both the shape compactness and the form factor of the polygons were also smaller for the GNSS-based method compared with the MLS-based method, with differences up to 10%. In conclusion, measurements recorded by GNSS were less accurate, and under certain forest conditions (dense canopies, rugged terrain), large systematic errors can occur and therefore limit its use.

Glucose Sensing Mediated by Portal Glucagon-Like Peptide 1 Receptor Is Markedly Impaired in Insulin-Resistant Obese Animals.

The glucose portal sensor informs the brain of changes in glucose inflow through vagal afferents that require an activated glucagon-like peptide 1 receptor (GLP-1r). The GLP-1 system is known to be impaired in insulin-resistant conditions, and we sought to understand the consequences of GLP-1 resistance on glucose portal signaling. GLP-1-dependent portal glucose signaling was identified, in vivo, using a novel 68Ga-labeled GLP-1r positron-emitting probe that supplied a quantitative in situ tridimensional representation of the portal sensor with specific reference to the receptor density expressed in binding potential units. It also served as a map for single-neuron electrophysiology driven by an image-based abdominal navigation. We determined that in insulin-resistant animals, portal vagal afferents failed to inhibit their spiking activity during glucose infusion, a GLP-1r-dependent function. This reflected a reduction in portal GLP-1r binding potential, particularly between the splenic vein and the entrance of the liver. We propose that insulin resistance, through a reduction in GLP-1r density, leads to functional portal desensitization with a consequent suppression of vagal sensitivity to portal glucose.

Radiological classification of dementia from anatomical MRI assisted by machine learning-derived maps

Background and purposeMany artificial intelligence tools are currently being developed to assist diagnosis of dementia from magnetic resonance imaging (MRI). However, these tools have so far been difficult to integrate in the clinical routine workflow. In this work, we propose a new simple way to use them and assess their utility for improving diagnostic accuracy. Materials and methodsWe studied 34 patients with early-onset Alzheimer's disease (EOAD), 49 with late-onset AD (LOAD), 39 with frontotemporal dementia (FTD) and 24 with depression from the pre-existing cohort CLIN-AD. Support vector machine (SVM) automatic classifiers using 3D T1 MRI were trained to distinguish: LOAD vs. Depression, FTD vs. LOAD, EOAD vs. Depression, EOAD vs. FTD. We extracted SVM weight maps, which are tridimensional representations of discriminant atrophy patterns used by the classifier to take its decisions and we printed posters of these maps. Four radiologists (2 senior neuroradiologists and 2 unspecialized junior radiologists) performed a visual classification of the 4 diagnostic pairs using 3D T1 MRI. Classifications were performed twice: first with standard radiological reading and then using SVM weight maps as a guide. ResultsDiagnostic performance was significantly improved by the use of the weight maps for the two junior radiologists in the case of FTD vs. EOAD. Improvement was over 10 points of diagnostic accuracy. ConclusionThis tool can improve the diagnostic accuracy of junior radiologists and could be integrated in the clinical routine workflow.

A Novel Spatiotemporal Data Model for River Water Quality Visualization and Analysis

River water quality (RWQ) data has obvious characteristics of spatial and temporal distribution, and tables are conventionally exploited for storage of multi-period monitoring data of RWQ; however, neither effective visualization nor accurate analysis of the obtained data can be realized due to its dispersion character. In this paper, a novel spatiotemporal data model is proposed for RWQ data to realize conveniently data representation and spatiotemporal analysis. In this model, a spatial point, containing both location and dynamic water quality information, is considered as the basic element of river spaces, and methods of expanding a point to a line segment, a flat surface and a cube are designed respectively so as to make this model be applicable to different generalizations of river spaces. Moreover, a temporal data storage structure is designed so that efficient inquiry and advanced analysis of RWQ data can be guaranteed and the occupied memory space can be reduced. Finally, case studies are conducted by performing 3D visualization, trend analysis and anomaly identification on RWQ data, the result of which showing that tridimensional representation of RWQ data can be realized efficiently, the computational complexity is reduced significantly and the occupied memory space of monitoring data is effectively economized. Accordingly, the proposed spatiotemporal data model can contribute to the efficient visualization and advanced analysis of RWQ data.

Enrichment of Human-Computer Interaction in Brain-Computer Interfaces via Virtual Environments.

Tridimensional representations stimulate cognitive processes that are the core and foundation of human-computer interaction (HCI). Those cognitive processes take place while a user navigates and explores a virtual environment (VE) and are mainly related to spatial memory storage, attention, and perception. VEs have many distinctive features (e.g., involvement, immersion, and presence) that can significantly improve HCI in highly demanding and interactive systems such as brain-computer interfaces (BCI). BCI is as a nonmuscular communication channel that attempts to reestablish the interaction between an individual and his/her environment. Although BCI research started in the sixties, this technology is not efficient or reliable yet for everyone at any time. Over the past few years, researchers have argued that main BCI flaws could be associated with HCI issues. The evidence presented thus far shows that VEs can (1) set out working environmental conditions, (2) maximize the efficiency of BCI control panels, (3) implement navigation systems based not only on user intentions but also on user emotions, and (4) regulate user mental state to increase the differentiation between control and noncontrol modalities.

WebLisling: A Web-based Therapeutic Platform for the Rehabilitation of Aphasic Patients

A new trend in medical therapy aims to take advantage of information technologies and, in particular, the Internet to provide home rehabilitation. In case of the aphasia treatment, which involves long and numerous sessions with a speech and language therapist, the implementation of Web-based software for rehabilitation appears to be a key issue. This is the purpose of WebLisling, a Web application developed to be a complementary aid in the process of rehabilitating aphasic Portuguese speaking patients. The article describes the platform's architecture and the group of exercises designed by therapists to enable the user to train different linguistic modalities (written and spoken comprehension and expression). Web3D technologies are used in order to present tasks that take place in the tri-dimensional representation of a flat, where the user can interact with domestic objects with the aim of promoting a treatment as ecologic as possible. This ultimate version of Lisling tools offers a user-friendly access to the therapeutic exercises (even for people with low computational skills) and a remote monitoring of patient's performances, which are recorded in a Web-based database. Preliminary testes carried out on a population of patients and therapists show promising results regarding usability and therapeutic potential of the application.

Deposition of intranasal glucocorticoids--preliminary study.

Intranasal glucocorticoids are the treatment of choice in the therapy of rhinitis. The differences in efficiency of particular medications proven by therapeutic index may result from differences in composition of particular formulations as well as from diverse deposition in nasal cavities. Intranasal formulations of glucocorticoids differ in volume of a single dose in addition to variety in density, viscosity and dispenser nozzle structure. The aim of this report was to analyze the deposition of most often used intranasal glucocorticoids in the nasal cavity and assessment of the usefulness of a nose model from a 3D printer reflecting anatomical features of a concrete patient. Three newest and most often used in Poland intranasal glucocorticoids were chosen to analysis; mometasone furoate (MF), fluticasone propionate (FP) and fluticasone furoate (FF). Droplet size distribution obtained from the tested formulations was determined by use of a laser aerosol spectrometer Spraytec (Malvern Instruments, UK). The model of the nasal cavity was obtained using a 3D printer. The printout was based upon a tridimensional reconstruction of nasal cavity created on the basis of digital processing of computed tomography of paranasal sinuses. The deposition of examined medications was established by a method of visualization combined with image analysis using commercial substance which colored itself intensively under the influence of water being the dominant ingredient of all tested preparations. On the basis of obtained results regions of dominating deposition of droplets of intranasal medication on the wall and septum of the nasal cavity were compared. Droplet size of aerosol of tested intranasal medications typically lies within the range of 25-150 µm. All tested medications deposited mainly on the anterior part of inferior turbinate. FP preparation deposited also on the anterior part of the middle nasal turbinate, marginally embracing a fragment of the central part of this turbinate as well together with deposition in the middle and superior nasal meatus reaching the region of nasal ceiling and olfactory field. MF preparation deposited on the anterior part of the inferior turbinate and central part of this turbinate alike. The area of mucous membrane of lateral wall of nasal cavity on which MF deposited was similar to the area achieved after the application of FP preparation but much greater than in the case of FF preparation. FF drug deposition concentrates only on the anterior part of the inferior turbinate. Despite directing the drug to the lateral wall of the nasal cavity a great proportion of examined preparations deposit also on the nasal septum. The practical application of tridimensional representation (3D printout) of actual geometry of nasal cavity to establish the deposition of inGKS was proven. Droplet size and the geometry of the aerosol cloud introduced into the nostril determine the significant deposition of medication droplets in the anterior part of the nasal cavity. Both physical properties of the drug as well as spraying system applied influence spatial distribution of the drug. The interaction of the air flow with the layer of deposited fluid plays a major role in the deposition of the drug in the nasal cavity, therefore it is so important that the drug does not drain by gravity but remains at the site of deposition which may be reinforced by thixotropic properties of the preparation.

Monitoring of chicken meat freshness by means of a colorimetric sensor array

A new optoelectronic nose to monitor chicken meat ageing has been developed. It is based on 16 pigments prepared by the incorporation of different dyes (pH indicators, Lewis acids, hydrogen-bonding derivatives, selective probes and natural dyes) into inorganic materials (UVM-7, silica and alumina). The colour changes of the sensor array were characteristic of chicken ageing in a modified packaging atmosphere (30% CO(2)-70% N(2)). The chromogenic array data were processed with qualitative (PCA) and quantitative (PLS) tools. The PCA statistical analysis showed a high degree of dispersion, with nine dimensions required to explain 95% of variance. Despite this high dimensionality, a tridimensional representation of the three principal components was able to differentiate ageing with 2-day intervals. Moreover, the PLS statistical analysis allows the creation of a model to correlate the chromogenic data with chicken meat ageing. The model offers a PLS prediction model for ageing with values of 0.9937, 0.0389 and 0.994 for the slope, the intercept and the regression coefficient, respectively, and is in agreement with the perfect fit between the predicted and measured values observed. The results suggest the feasibility of this system to help develop optoelectronic noses that monitor food freshness.

Aplicación de Teorías de Color en Imágenes Digitales

Recent works with colour spaces in digital imagen processing are related to colour image segmentation, texture analysis, image morphology, colour image standardization, and object localization. Non-linear systems are frequently present in non-traditional colour spaces (Hering Space) since they help to enhance some specific image characteristics. The present work is related with the study and application of two colour theories: Opponent Colours and Tricromaticity (RGB) as tridimensional representations, using linear and non-linear transformations among these colour spaces. In addition, this paper presents two numeric solutions to solve the implicit non-linear equation system. Due to the positive results obtained with the proposed algorithms, they were implemented to develop a computerized license plate identification system with the introduction of illumination effects.

Acoustic properties of wood in tridimensional representation of slowness surfaces

Mechanical behaviour of wood considered as an orthotropic solid can be determined with ultrasonic technique. The propagation phenomena in wood are complex and theoretically are regulated by Christoffel's equation. Three type of waves can propagate in wood. During the propagation phenomena three slowness sheets are observed, corresponding to a fast longitudinal wave (inner sheet) and two shear waves, one fast and one slow (outer sheet). These waves are submitted continuously to mode conversion phenomena. The polarization angle changes when the propagation direction is out of the principal directions of symmetry of the material. In this article an analysis of the propagation phenomena in tridimensional representation is performed for different wood species. This approach contributes to the understanding of dynamic aspects of particle displacement associated with the wave fronts propagation. Globally, the anisotropy of each species, expressed by their acoustical behaviour is well represented.

Sistema automático para la correlación anatomofisiológica en tres planos simultáneos durante la neurocirugía funcional

The Neurosurgical Deep Recording System (NDRS) using a personal computer takes the place of complex electronic equipment for recording and processing deep cerebral electrical activity, as a guide in stereotaxic functional neurosurgery. It also permits increased possibilities of presenting information in direct graphic form with automatic management and sufficient flexibility to implement different analyses. This paper describes the possibilities of automatic simultaneous graphic representation in three almost orthogonal planes, available with the new 5.1 version of NDRS so as to facilitate the analysis of anatomophysiological correlation in the localization of deep structures of the brain during minimal access surgery. This new version can automatically show the spatial behaviour of signals registered throughout the path of the electrode inside the brain, superimposed simultaneously on sagittal, coronal and axial sections of an anatomical atlas of the brain, after adjusting the scale automatically according to the dimensions of the brain of each individual patient. This may also be shown in a tridimensional representation of the different planes themselves intercepting. The NDRS system has been successfully used in Spain and Cuba in over 300 functional neurosurgery operations. The new version further facilitates analysis of spatial anatomophysiological correlation for the localization of brain structures. This system has contributed to increase the precision and safety in selecting surgical targets in the control of Parkinson s disease and other disorders of movement.

Helical representation of atrial reentry: a teaching aid for electrophysiology.

Cardiac clinical electrophysiology is difficult to teach because it requires mental integration of complex information on cardiac activation, which includes tridimensional spatial orientation of the cardiac structures involved and variables such as refractory period, conduction velocity, and cycle length. Commonly used representations of cardiac arrhythmias include snapshot sequences or ladder diagrams. The former lack time dimension, and the latter lack spatial dimension. We propose a schematic tridimensional representation of reentry as a helicoidal shape that is the result of adding a time dimension to a circular representation. This presentation, which also can be called a "loop diagram," allows better integration of spatial phenomena with recorded electrogram sequences and can help the teaching of basic clinical electrophysiology.

Peroral Sustained-Release Film-Coated Pellets as a Means to Overcome Physicochemical and Biological Drug-Related Problems. I. In Vitro Development and Evaluation

In vitro preformulation testing has shown that the solubility and dissolution rate of the model drug compound ucb 11056 are highly pH dependent. Considering this, different sustained-release (SR) oral dosage forms of ucb 11056 were developed aiming to obtain the most constant and complete release of the drug during transit in the gastrointestinal (GI) tract. Classical approaches based on the use of SR formulations such as hydrophilic matrix tablets or pellets coated with one film-forming polymer (Eudragit NE30D or L30D-55) did not fulfill all expectations on the basis of their in vitro evaluation, i.e., the drug release and pattern remained highly dependent on the pH of the dissolution medium. Therefore, taking advantage of the flexibility of release adjustment obtainable from coating of pellets with different kinds of pH-sensitive film layers, a quite satisfactory pH independence of the release characteristics was obtained using formulation blends of neutral and anionic acrylic polymers. For the selected SR pellets batch 15 coated with NE30D/L30D-55 (7:3), the tridimensional topographic representation of the drug release versus time and pH showed that, notwithstanding the pH-dependent aqueous solubility of the drug, the release profiles were relatively homogeneous for any pH value ranging between 1 and 7.

A Tridimensional Representation of Enzyme Inhibition Useful for Diagnostic Purposes

A new three dimensional representation of enzyme inhibition, applied to Lineweaver-Burk, Hanes and Eadie-Hofstee plots is presented. This type of representation has advantages for enzyme inhibition diagnosis, showing graphic characteristics that pass unnoticed in linear plots.

Displacement activity of bisbenzylisoquinoline alkaloids at striatal 3H-SCH 23390 and 3H-raclopride binding sites.

Fifteen bisbenzylisoquinoline alkaloids (BBIQ) with one ether bridge (thaligrisine [1], berbamunine [2], dimethylgrisabine [3], pampulhamine [4], and methyl-dauricine [5]), with two ether bridges (homoaromoline, isotetrandrine, and obaberine), with one ether bridge and one biphenyl bridge (oxandrine, dimethylpseudoxandrine, pseudoxandrine, and antioquine) or secoderivatives (secoobaberine, secoantioquine, and secolucidine), were tested for their ability to displace 3H-raclopride or 3H-SCH 23390 from their specific dopaminergic binding sites to rat striatal membranes. The most active compounds were found in the group of BBIQs with one ether bridge. Inactive or weakly active compounds were found in this group of BBIQs with one ether bridge and in the other groups. Analysis of tridimensional representations indicates that the differnt activities among the BBIQs with one ether bridge could be related to strong differences between the spatial occupancy of these compounds according to their stereochemistry.

Genetic structures in the Po Delta: principal components, systemic functions and the relative age of the beta-thalassemia polymorphism.

The principal component representations of the genetic structure of the human population of the Po Delta, obtained from 7 polymorphic loci, are compared with the representations obtained from the systemic function of gene frequencies devised by Womble 1951. It is noted that, when tridimensional representations are used, some consistency is visible in the results of the two methods for the description of the genetic population structure in the area under study. Both methods indicate that the present structure of the balanced polymorphism for beta-thalassemia in the area appears to be more recent than the structure of the neutral polymorphisms studied.

A correlation between angle of friction, angle of failure plane and strength for compacts of tartaric acid, microcrystalline cellulose and mixture of the two

The angle of shearing resistance ø and the direction of the failure plane when two powders (tartaric acid and microcrystalline cellulose) and a mixture of these two powders underwent uniaxial compaction were calculated from the applied and radial stresses produced in an instrumented punch and die assembly. A tridimensional representation of the compacting process involving all three parameters associated with compaction — the shear stress, τ, normal stress σ and compact volume V — showed that the ratio of shear stress to normal stress on the failure plane remained constant during the last stages of densification for tartaric acid and mixtures. A logarithmic correlation existed between the diametral crushing strength, σ t, of the resultant compacts and both the angle of shearing resistance and the angle of the failure plane in the compacting materials.

Abundance Effects for the A0–G2 Stars in the Geneva System

The abundance effects on the tri-dimensional representation for the A0-G2 stars in the Geneva system are reviewed. B2–V1 anddare not affected by the Am characteristic, but B2–V1 is too blue (blocking effect on V1) anddsmaller for the Ap stars. For B2–V1 ≥ 0.230, we have a residual effect Δ(B2–V1) = 1.20 (Δm∗2+ 0.060). d is also affected and the residual effect is Δd= −0.4 Δm2for Δm2≥ −0.060 and Δd= −1.1 Δ(B2–V1) −0.024 for Δm2< −0.060.The abundance effects on the relations between B2–V1 and the parameters of temperature in other systems are studied.