Principal Values Research Articles

Validation of morphological ear classification devised by principal component analysis using three-dimensional images for human identification.

This study attempts to classify ear morphology for human identification in forensic investigations by distinguishing between the upper auricle and lobule areas. A three-dimensional homologous model of the ear was created using 414 ear images of males aged 17-93 years reconstructed from computed tomography scans of forensic autopsy cases. Morphological changes were visualized using principal component analysis and areas of significant individual differences within the entire ear were identified. The classification criterion images for the upper auricle (ten images) and lobule (12 images) were developed by combining multiple principal component values: components 1-5 for the upper auricle and 1-6 for the lobule. Three-dimensional ear images of the upper auricle and lobule areas from 414 subjects were categorized using a measurement method based on the minimum distance between 5,507 corresponding points. The results indicate the applicability of the criterion images for the morphological classification of ears in this study.

Electron paramagnetic resonance study of the paramagnetic centers in gamma-irradiated 2-nitrobenzoic acid single crystal

2-nitrobenzoic acid (C7H5NO4) (2NBA) single crystals were made paramagnetic using 60Co-gamma rays. An attempt was made to detect the resonance form formed in 2-nitrobenzoic acid single crystal with Electron Paramagnetic Resonance (EPR) Spectroscopy. EPR spectra were taken at 125 K in three different axes of the crystal. As a result of EPR analysis of gamma irradiated 2NBA single crystal, it was understood that 2NBA anion radical was formed. The principal values of the hyperfine structure constants, the principal values of the g-tensor and their direction cosines were calculated.

Attributes of the Romanian State. Special View on the Rule of Law

The attributes of a state constitute its defining features and principal values of its constitutional order, which differentiate or resemble it as a political-legal physiognomy from other states. The rule of law, pluralism, democracy, civil society are universal values of contemporary political thought and practice and can be found normatively expressed in international documents, but also in the Romanian Constitution. Starting from the specialised doctrine and jurisprudence of the Constitutional Court of Romania in the matter, this article analyses the attributes of the Romanian state enshrined by the Constitution, respectively: rule of law; welfare state; pluralistic state; democratic state. In this study, a special attention is dedicated to the rule of law, considering the dangers that threaten it in the current period. Legislative inflation, superficial legislation, increasing the role of the Executive in the field of legislation at the expense of Parliament, the intrusions of politicians into the sphere of judicial power are just some of the dysfunctions of the Romanian rule of law. In this context, this article highlights the essential role of the Constitutional Court in guaranteeing and respecting the requirements of the rule of law. Through its jurisprudence, an important contribution is made not only in the correct interpretation and application of constitutional norms, but also in their elaboration. Under the influence of the specific socio-political factors in each country, the pressures of the Union and international law, the rule of law cannot reach perfection, but it remains a fundamental constitutional necessity whose primary purpose is to ensure the rights and freedoms of citizens. Keywords: attributes of the state, rule of law, the jurisprudence of the Constitutional Court of Romania, dysfunctionalities of the Romanian rule of law.

X-ray diffraction, luminescence, and electron paramagnetic resonance study of LaLuO3:Yb3+ nanopowders

The primary objective of materials science is the study of the properties of the existing materials and the development of new ones. In the present day, the use of solid-state lasers abroad has prompted material scientists globally to develop novel or enhance the properties of the existing active gain media. Materials comprising rare earth elements have historically proven effective in scintillation applications. The synthesis of LaLu1-xYbxO3 monodisperse nanopowders with a particle size of 50–62 nm via the Pechini complexing citrate method has been the subject of investigation using electron paramagnetic resonance (EPR) spectroscopy and photoluminescence (PL) measurements. The EPR data indicate that the Yb³⁺ ions predominantly create a single type of center, whereby the Yb³⁺ ion substitutes for the Lu³⁺ ion. The calculated EPR g-factors are estimated to be g1 = 3.85, g2 = 2.15, g3 = 1.55 and the 171Yb isotope hyperfine interaction constants are A1 = 600 × 10−4 cm−1, A2 = 700 × 10−4 cm−1, A3 ≈ 1800 × 10−4 cm−1. The principal values of the g factors and the hyperfine tensors indicate that the Yb site in LaLu1-xYbxO3 nanopowders exhibits orthorhombic symmetry. The PL measurements in the wavelength range of 350–1800 nm, with excitation provided by either a xenon lamp or a diode laser, indicate the presence of a broad emission band, centered at 404 nm, in addition to the well-known emission spectrum in the IR region (920–1100 nm) arising from Yb3+ ions.

Disruption of network hierarchy pattern in bulimia nervosa reveals brain information integration disorder

The human brain works as a hierarchical organization that is a continuous axis spanning sensorimotor cortex to transmodal cortex (referring to cortex that integrates multimodal sensory information and participates in complex cognitive functions). Previous studies have demonstrated abnormalities in several specific networks that may account for their multiple behavioral deficits in patients with bulimia nervosa (BN), but whether and how the network hierarchical organization changes in BN remain unknown. This study aimed to investigate alterations of the hierarchy organization in BN network and their clinical relevance. Connectome gradient analyses were applied to depict the network hierarchy patterns of fifty-nine patients with BN and thirty-nine healthy controls (HCs). Then, we evaluated the network- and voxel-level gradient alterations of BN by comparing gradient values in each network and each voxel between patients with BN and HCs. Finally, the association between altered gradient values and clinical variables was explored. In the principal gradient, patients with BN exhibited reduced gradient values in dorsal attention network and increased gradient values in subcortical regions compared to HCs. In the secondary gradient, patients with BN showed decreased gradient values in ventral attention network and increased gradient values in limbic network. Regionally, the areas with altered principal or secondary gradient values in BN group were mainly located in transmodal networks, i.e., the default-mode and frontoparietal network. In BN group, the principal gradient values of right inferior frontal gyrus were negatively associated with external eating behavior. This study revealed the disordered network hierarchy patterns in patients with BN, which suggested a disturbance of brain information integration from attention network and subcortical regions to transmodal networks in these patients. These findings may provide insight into the neurobiological underpinnings of BN.

Nc -insensitivity of QCD2A

The spectrum of two-dimensional adjoint QCD is surprisingly insensitive to the number of colors Nc of its gauge group. It is argued that the cancellation of finite Nc terms is rather natural and ultimately a consequence of the singularity structure of the theory. In short, there are no finite Nc terms, hence effectively there cannot be any finite Nc singular terms, since the former are necessary to guarantee well-behaved principal value integrals. We evaluate and categorize the matrix elements of the theory’s light-cone Hamiltonian to show how terms emerging from finite Nc contributions to the anticommutator cancel against contributions from the purely finite Nc term of the Hamiltonian. The cancellation is not complete; finite terms survive and modify the spectrum, as is known from numerical work. Additionally we show that several parton-number changing finite Nc matrix elements vanish independently of finiteness requirements. In particular, there is only one trace-diagonal finite Nc correction. It seems therefore that considering matrix elements rather than individual contributions can provide substantial simplifications when computing the spectrum of a theory with a large symmetry group. Published by the American Physical Society 2024

Impressive weight loss induced by a very low-calorie ketogenic diet in a morbidly complex obese patient with a recent episode of acute kidney injury and advanced chronic kidney disease: a case report

The very low-calorie ketogenic diet (VLCKD), characterized by a marked energy restriction that induces rapid weight loss, has recently been proposed as a valid nutritional strategy for managing obesity. VLCKD is commonly considered dangerous for the kidneys due to the misconception that it is high in protein, beyond the risk of electrolyte imbalances and an increase in diuresis. We report a case of safe and effective weight loss induced by VLCKD in a 43-year-old Caucasian woman with a recent episode of acute kidney injury on advanced chronic kidney disease. Surprisingly, we observed that after the diet-induced weight loss, not only did renal function not worsen, but proteinuria also improved. The principal value of this case report is its singular demonstration of impressive weight loss induced by VLCKD in a complex obese patient that was apparently not accompanied by the development of serious adverse sequelae.

Dynamic response and safety performance of composite-laminated heliostat under hail impact

ABSTRACT Areas rich in solar energy are prone to strong convective weather, leading to severe hail disasters, which makes heliostats under the threaten of hail impacts. An evaluation model of composite laminated heliostat under hail impacting is established and validated. Subsequently, the effect of interlayer type and thickness ratio on the dynamic response and safety assessment of composite laminated heliostats impacted by hail are investigated. Additionally, the velocity thresholds for hail terminal velocity of composite laminated heliostats with a thickness range of 2–4 mm, based on the optimal thickness ratio, are studied. The results indicate that the maximum principal stress value of the composite laminated heliostat remains similar to that of the single-layer heliostat when the interlayer types are SentryGlas Plus (SGP) and Polyvinyl Butyral (PVB). The maximum principal stresses of single-layer heliostats with thicknesses of 2-4 mm are 2.92, 1.50, and 1.35 times, compared to the first-layer glass of composite laminated heliostat with the same thickness under the optimal thickness ratio, which indicates that the hail resistance of the composite laminated heliostat is superior to that of the single-layer heliostat. The findings offer the guidance for the hail resistance of composite laminated heliostat under hail impact.

γ-radiation-induced centers in irradiated perovskite SrCeO3 and their role in thermally stimulated reactions: Fluorescence, thermally stimulated luminescence, electron paramagnetic resonance and shielding studies

One promising host for actinide radioactive wastes is orthorhombic perovskite-type oxide. Perovskite SrCeO3 ceramic was synthesized by nitrate-fuel combustion, which includes the organic fuel glycine. Powder X-ray diffraction was utilized to determine the structural features, and γ-radiation-induced changes and shielding properties were investigated in perovskite SrCeO3. In a mixed-phase sample, a bright sky-blue luminescence was observed, and two thermoluminescence (TL) peaks were seen in irradiated SrCeO3 ceramic. Electron paramagnetic resonance (EPR) spectrum in γ-irradiated SrCeO3 ceramic had contributions from five defect centers. Center I having an isotropic g-value equal to 2.0283, is ascribed to an O− ion, while center II with an axial g-tensor with principal values g|| = 2.0224 and g⊥ = 2.0068 is determined as an O2− ion. O− ion relates to the TL peak at 215 °C. Center III with a g-value equal to 2.0009 is identified as an F+ center and is related to the 185 °C TL peak. The defect center associated with center IV is also identified as an F+ center. An additional defect center in the higher field region of the spectrum is assigned to an F+ center, and the center results from an F-center (oxygen vacancy with two electrons). The mass attenuation coefficients, effective atomic numbers, and half-value layer thicknesses concerning shielding property effectiveness were computed and it was found that the perovskite SrCeO3 ceramic provided superior γ-shielding properties.

On quadrature of highly oscillatory Bessel function via asymptotic analysis of simplex integrals

In this article, two methods for evaluating highly oscillatory Bessel integrals are explored. Firstly, a polynomial is analyzed as an effective approximation of the simplex integral of a highly oscillatory Bessel function based on Laplace transform, and its error rapidly decreases as the frequency increases. Furthermore, the inner product of f and highly oscillatory Bessel function can be approximated by two other forms of inner product by which one depends on a polynomial and the higher derivatives of f, another depends on Bessel function and the interpolation polynomial of f. In addition, three issues related to highly oscillatory Bessel integrals have also been discussed: inequalities for the convergence rate of Filon-type methods, evaluation of Cauchy principal values, and simplified evaluation on infinite intervals. Through some preliminary numerical experiments, our theoretical analysis has been preliminarily confirmed, and the proposed numerical method is accurate and effective.

On the equivalence of demagnetization tensors as discrete cell size approaches zero in three-dimensional space.

The calculation of the demagnetization field is crucial in various disciplines, including magnetic resonance imaging and micromagnetics. A standard method involves discretizing the spatial domain into finite difference cells and using demagnetization tensors to compute the field. Different demagnetization tensors can result in contributions from adjacent cells that do not approach zero, nor do their differences, even as the cell size decreases. This work demonstrates that in three-dimensional space, a specific set of magnetization tensors produces the same total demagnetization field as the Cauchy principal value when the cell size approaches zero. Additionally, we provide a lower bound for the convergence speed, validated through numerical experiments.

Comprehensive measurement of three-dimensional thermal conductivity tensor using a beam-offset square-pulsed source (BO-SPS) approach

Accurately measuring the three-dimensional thermal conductivity tensor is essential for understanding and engineering the thermal behavior of anisotropic materials. Existing methods often struggle to isolate individual tensor elements, leading to large measurement uncertainties and time-consuming iterative fitting procedures. In this study, we introduce the Beam-Offset Square-Pulsed Source (BO-SPS) method for comprehensive measurements of three-dimensional anisotropic thermal conductivity tensors. This method uses square-pulsed heating and precise temperature rise measurements to achieve high signal-to-noise ratios, even with large beam offsets and low modulation frequencies, enabling the isolation of thermal conductivity tensor elements. We demonstrate and validate the BO-SPS method by measuring X-cut and AT-cut quartz samples. For X-cut quartz, with a known relationship between in-plane and cross-plane thermal conductivities, we can determine the full thermal conductivity tensor and heat capacity simultaneously. For AT-cut quartz, assuming a known heat capacity, we can determine the entire anisotropic thermal conductivity tensor, even with finite off-diagonal elements. Our results yield consistent principal thermal conductivity values for both quartz types, demonstrating the method's reliability and accuracy. This research highlights the BO-SPS method's potential to advance the understanding of thermal behavior in complex materials.

The Effects of using PEEK Coping and Different Restorative Materials on the Stress Distribution in Tooth and Implant- supported Prostheses under Static Loading: 3D FEA.

This study was designed to evaluate the influence of utilizing Polyetheretherketone (PEEK) coping and three different dental restorative materials in the success of tooth and implant-supported fixed partial dentures (TISFPD) in the maxillary posterior region, under static loading by 3-Dimensional Finite Element Analysis (3D FEA). Six 3D FEA models were designed assuming the extraction of maxillary first and second molars. Bone, implant, abutment, PEEK coping, second premolar, periodontal ligament (PDL) and six 3-unit TISFPD with different restorative materials [Porcelain-Fused-to-Metal (PFM), PEEK-Composite (PC), Monolithic Zirconia (MZ)] were modeled. Then, PEEK copings were modeled to be cemented onto the implants as a double-crown system for the first three groups (PFMPEEK, PCPEEK and MZPEEK) whereas, the next three groups (PFM, PC, MZ) excluded a PEEK coping in their designs. The prostheses were loaded twice, vertically and obliquely. From the determined points, 250 N for vertical loading (0o to the long axis) and 200 N for the oblique loading (30o to the long axis) were applied. Von Mises tension, maximum and minimum principal tension value criterias were analyzed. Regardless of the material used for suprastructure, the maximum average stress was reduced by using PEEK coping. Considering the maximum stress distribution, PC appeared to have the highest stresses on the cortical bone, implant and screw. Additionally, the von Mises stresses formed in the PDL for each model were lower when PEEK coping was included in the design of the TISFPD, reducing the risk of intrusion. The stress distribution was positively affected by the PEEK coping in TISFPD design, reducing bone resorption and failure. This elastic material used generated lower stresses in the bone and implant, while no significant effect was found on stresses around natural teeth.

Effect of pre-straining direction on the microstructure, mechanical properties and microstructural response of AA2099-T83 Al-Li alloy

Understanding the microstructural evolution and anisotropic behavior of Al-Li alloys after pre-deformation in different directions is crucial for optimizing their forming performance. This study investigates the microstructural evolution in AA2099 Al-Li alloy rolled sheets after pre-deformation in the extrusion direction (ED) and transverse direction (TD), and the resulting changes in mechanical properties during subsequent tensile deformation. A crystal plasticity finite element model (CPFEM) was established to quantitatively analyze the link between pre-deformation direction and the microstructural response during the hardening stages of tensile deformation. The results showed that the differences in mechanical properties due to pre-deformation direction are mainly attributed to the variations in volume fraction and diameter of the T1 precipitates. The contributions of T1 phase to yield strength are estimated to be 239 MPa (ED) and 223 MPa (TD), respectively. An increase in T1 (Al2CuLi) phase volume fraction and a decrease in phase diameter lead to higher average von Mises stress and average maximum principal strain values during the hardening stages.

Evaluation of stress distributions in endodontically treated anterior incisors under occlusal and trauma-induced forces following various restoration treatments: A finite element analysis.

The aim of this study was to calculate the stress distribution of fiberglass post associated with resin composite crown restoration and fiberglass posts with zirconia restorations in mature and immature endodontically treated central maxillary incisor under various loading conditions. The study created six different study models in a virtual environment: healthy mature maxillary central teeth, intact immature maxillary central teeth, mature maxillary central teeth with fiberglass post associated with resin composite crown restoration, immature maxillary central teeth with fiberglass post associated with resin composite crown restoration, mature maxillary central teeth with fiberglass posts and zirconia restoration, and immature maxillary central teeth with fiberglass posts and zirconia restoration. Loading conditions simulating mastication, trauma, and bruxism were applied to each of the models at different angles and amounts. The von Mises and the maximum and minimum principal stress values in tooth structures (dentin) and support structures (bone, PDL) and materials were observed using finite element stress analysis. The highest stress values in the tissue and the restoration structure were observed for masticating force and crowns rehabilitated with zirconia restorations. None of the compared loading conditions and restorations showed destructive stress values on periodontal ligament or bone. The mature and immature endodontically treated central maxillary incisors can be better rehabilitated using fiberglass post associated with resin composite crown restoration and may be preferred to zirconia restorations in order to reduce the stresses on the surrounding tissues and teeth. However, further clinical studies are needed to fully explore this topic.

Electrically Induced Crystal Field Distortion in a Ferroelectric Perovskite Revealed by Electron Paramagnetic Resonance.

The magnetoelectric material has attracted multidisciplinary interest in the past decade for its potential to accommodate various functions. Especially, the external electric field can drive the quantum behaviors of such materials via the spin-electric coupling effect, with the advantages of high spatial resolution and low energy cost. In this work, the spin-electric coupling effect of Mn2+-doped ferroelectric organic-inorganic hybrid perovskite [(CH3)3NCH2Cl]CdCl3 with a large piezoelectric effect was investigated. The electric field manipulation efficiency for the allowed transitions was determined by the pulsed electron paramagnetic resonance. The orientation-included Hamiltonian of the spin-electric coupling effect was obtained via simulating the angle-dependent electric field modulated continuous-wave electron paramagnetic resonance. The results demonstrate that the applied electric field affects not only the principal values of the zero-field splitting tensor but also its principal axis directions. This work proposes and exemplifies a route to understand the spin-electric coupling effect originating from the crystal field imposed on a spin ion being modified by the applied electric field, which may guide the rational screening and designing of hybrid perovskite ferroelectrics that satisfy the efficiency requirement of electric field manipulation of spins in quantum information applications.

Effect of different occlusal materials on peri-implant stress distribution with different osseointegration condition: A finite element analysis.

Studies have not been done to evaluate the peri-implant stress exerted by materials(like PEEK and resin matrix ceramics) in different osseointegration conditions. To investigate the effect of different occlusal materials on peri-implant stress distribution with different osseointegration condition using finite element analysis. Eighteen different 3D FEA models of implant fixed with abutment were created involving 6 different occlusal materials (Heat cured temporary acrylic resin (PMMA), Bis-GMA, PEEK, Lithium disilicate, Resin matrix ceramics and translucent Zirconia) and different osseointegrated conditions (50%, 75%, 100%). Models were subjected to loading vertically and obliquely followed by evaluation of stress distribution. The results of the simulation obtained were analysed in terms of Von mises, maximum principal and minimal principal stresses using descriptive stastistics. PMMA (40.14 MPa on vertical loading and 66 MPa on oblique loading) resulted in the highest stresses and lithium disilicate (24 MPa on vertical loading and 52.40 MPa on oblique loading) resulted in least stresses among all the crown materials. Upon oblique loading, von Mises stress increases except for translucent zirconia and lithium disilicate (52.444 MPa on 50%, 47.733 MPa on 75%, and 43.973 MPa on 100% osseointegration). Minimal principal stress values decreased with increase in osseointegration upon oblique loading for PMMA, BisGMA, and PEEK. Translucent zirconia and lithium disilicate offer a better stress transmission. Minimal principal stress values of PEEK and BisGMA decreased with increasing osseointegration.

Biomechanical Effects of Titanium and Carbon Fiber Reinforced PEEK as Dental Implant Material: A Finite Element Analysis.

The aim of this study is to examine the stresses on the peri-implant bone under occlusal forces of 30% Carbon fiber reinforced PEEK (Cfr-PEEK) and 60% Cfr-PEEK materials that can be used as an alternative to titanium dental implants by finite element analysis. Single-tooth implants of 30% Cfr-PEEK, 60% Cfr-PEEK and titanium were modeled in each of the maxillary anterior, maxilla posterior, mandibular posterior regions. As a result of the applied vertical and oblique forces; Von Misses stress, maximum principal stress and minimum principal stress values and stress distributions in the implant, cortical bone and spongious bone in each of the models were examined. 30% Cfr-PEEK implants stress in the surrounding bone was higher than titanium and 60% Cfr-PEEK implants. The 60% Cfr-PEEK material displayed lower stress distribution on both cortical and spongious peri-implant bone in all models. Titanium and 60% Cfr- PEEK implants exhibited biomechanically similar behavior and these implants conducted stresses to bone more homogeneous than the 30% Cfr-PEEK implants. Overall, oblique forces had more destructive effect than vertical forces and denser bone structure showed better stress distribution against incoming forces. For the routine use of Cfr-PEEK material as dental implant material; animal and long-term clinical studies are needed.

КОНЦЕПТУАЛЬНЫЕ, КОНТЕКСТУАЛЬНЫЕ И ЦЕННОСТНЫЕ ОСОБЕННОСТИ ЭТНИЧЕСКИХ СМИ В СИСТЕМЕ МЕДИА ЮГА РОССИИ

The article summarizes and categorizes various theoretical and methodological approaches to the concept of ethnic media, as well as analyses their place and role in the system of Russian media and that of the South of Russia in particular. The research reveals such contextual peculiarities of ethnic media as bilingualism, focusing on a specific ethnic community and meeting its needs, as well as creating and maintaining ethnic identity. Among other concepts, the predominant are traditional values, interethnic collaboration and preserving historical memory and culture. The principal values spread by the ethnic media of the South of Russia are interethnic cooperation, language preservation, as well as maintenance of cultural achievements and people’s identity.

Evaluation of stress distribution of different marginal designs on PEEK and PEKK substructure materials, cortical and cancellous Bone:A finite element analysis

High-performance polymers are used in different fixed prosthesis treatments due to their many advantages such as biocompatibility, shock absorption ability, high fracture resistance. The effects of marginal design on the forces on high-performance polymers are unknown. This study aimed was to investigate the stress distribution of different marginal designs on Polyetheretherketone (PEEK) and Polyetherketoneketone (PEKK) substructure materials, cortical bone and cancellous bone by finite element analysis. A first maxillary molar tooth was modeled in 3D using the "3D Complex Render" method. Considering the ideal preparation conditions (Taper angle was 6°, step depth was 1 mm, occlusal reduction was 2mm), four different configurations were modeled by changing the marginal design (chamfer, deep chamfer, shoulder 90°, shoulder 135°). PEEK, PEKK substructure, and composite superstructure were designed on created models. A total of 150N oblique force from two points and a total of 300N vertical force from three points were applied from occlusall. and the maximum principal stress, minimum principal stress, von Mises stress findings in the cortical bone, spongiose bone, and substructure were examined. The study was carried out by static linear analysis with a three-dimensional finite element stress analysis method. The highest maximum principal stress value in the cortical bone was observed when the PEEK+Shoulder 135° step at vertical force. The highest minimum principal stress value in the cortical bone was observed when the PEEK+Shoulder 90° step, and PEEK+deep chamfer step at oblique force. The highest maximum principal stress value in spongiose bone was observed when the PEEK+Shoulder 90° step. The highest minimum principal stress value in spongiose bone was observed when the PEEK+deep chamfer step at vertical force. The highest von Mises stress value in the substructure was observed when the PEKK+Deep chamfer step at oblique force. The lowest maximum principal stress value in the cortical bone was observed when the PEKK+Shoulder 135° step at oblique force. The lowest minimum principal stress value in the cortical bone was observed when the PEEK+Shoulder 135° step, and PEKK+shoulder 135° step at vertical force. The lowest maximum principal stress value in spongiose bone was observed when the PEEK+Shoulder 90° step. The lowest minimum principal stress value in spongiose bone was observed when the PEEK+Shoulder 135° step and PEKK+Shoulder 135° step at vertical force. The lowest von Mises stress value in the substructure was observed when the PEEK+Deep chamfer step at vertical force. When cortical and spongiose bone stress were evaluated, no destructive stress was observed. Considering the stresses occurring in the substructure the highest stress was observed in the chamfer step.