Structure-related Parameters Research Articles

Evaluation of Real-Time Three-Dimensional Echocardiography in Right Ventricular Function and Hemodynamics in Patients with Idiopathic Pulmonary Hypertension

Objective: Oriented with the assessment on real-time echocardiography based upon three dimensions (RT-3DE) in estimating right ventricular function and hemodynamics in the patients undergoing idiopathic pulmonary hypertension. Methods: Sixty patients living with idiopathic pulmonary hypertension admitted to our hospital from September 2018 to June 2019 were enrolled. Another 20 healthy examiners were selected as healthy controls. According to pulmonary systolic blood pressure, 60 patients were divided into 20 mild patients, 20 moderate ones as well as 20 severe ones. RT-3DE was used to measure right heart structure related parameters in all subjects, including left ventricular transverse diameter (LVTD), right ventricular transverse diameter (RVTD), right ventricular global end diastolic volume (EDV), right ventricular ejection fraction (RVEF). End-systolic volume (ESV), stroke volume (SV), as well as hemodynamic parameters, including pulmonary systolic pressure (SPAP), right heart output (RCO), pulmonary diastolic blood pressure (DPAP), pulmonary arterial pressure (MPAP). The differences in right heart structure parameters and hemodynamic parameters betwixt the PH Group and the healthy control Group were compared. In addition, conventional two-dimensional echocardiography (2DE) and RT-3DE were used to compare the images of the patients who had serious pulmonary hypertension and those of the Control Group to analyze the tricuspid annulus systolic displacement (TAPSE), the Tei index, and the tricuspid annulus systolic peak velocity (S’) value. The Result is that SPAP, DPAP, and MPAP achieved higher level in the PH Group compared to those in the Healthy Group, and P < 0005, the difference took on statistical significance. Those data of SPAP, DPAP and MPAP in the moderate and severe PH Group were higher than those in the mild PH Group, and P < 0005, the difference was of statistical significance. The RCO of the patients from the PH Group as well as the Healthy Group got under comparison, and P < 0005. They presented statistics-based dramatic difference. In addition, RCO showed a gradual decline in the patients who came down with mild, moderate, and serious PH, and the results were statistically significant. In addition, the comparison between RT-3DE and conventional echocardiography shows that RT-3DE has higher accuracy and diagnostic value.

The body composition analysis as a complementary tool in the screening of bone structural abnormalities.

Purpose. The importance of early diagnosis, bone-healthy lifestyle and medication is required for remaining fracture free. Dual-energy X-ray absorptiometry and ultrasound densitometry are widely used to screen osteoporosis and other bone structural diseases. Bioelectrical impedance analysis (BIA) devices can also estimate bone mineral content (BMC), but it has not been recommended for diagnostic purposes. The aim was to analyse whether low levels of the body composition' components and low bone mineral content can predict bone structural risk. Methods. Healthy pre- (n: 235, 18-45 years) and postmenopausal women (n: 137, 46-78 years) were enrolled to the analysis. BMC (kg) was estimated by InBody 720 analyser. Bone structure was measured by ultrasound DTU-One osteometer. Broadband ultrasound attenuation (BUA, dB/MHz), which estimates structural characteristics of trabecular bone, was used to assess bone structure. Body mass components were estimated by Drinkwater-Ross method. Results. Age changes of BMC, absolute and relative bone mass, muscle mass and bone structural parameters were analysed in women. BMC (r = 0.43, p < 0.01), absolute muscle mass (r = 0.41, p < 0.01) and absolute bone mass (r = 0.37, p < 0.01) were highly correlated (Pearson correlation) with BUA in premenopausal women. In postmenopausal women weaker relationship was identified between BUA and its hypothetical predictive factors. Conclusion. BMC and other studied body mass components alone do not provide enough information to identify osteoporosis, but can complete and widen the screening methods for bone structural diseases. Bone mineral density of healthy premenopausal women with low BMC, low bone mass and/or low muscle mass values should be measured regularly.

Crystallinity Improvement of Co3O4 by Adding Thiourea

Tricobalt tetraoxide (Co3O4) samples having different thiourea/Co molar ratio of 0, 5 and 10 were prepared by wet chemical synthesis. The effects of thiourea content on the crystal structure-related parameters of Co3O4 were determined. The increase in the amount of thiourea caused a gradual decrease in the lattice parameters and specific surface area and an increase in the crystallinity and crystallite size. The experimental analysis results showed that thiourea content can be used to control the crystal structure-related parameters of Co3O4.

Complete optical absorption in hybrid halide perovskites based on critical coupling in the communication band.

In order to remarkably enhance the absorption capability of (CH3NH3)PbI3, a tunable narrow-band (CH3NH3)PbI3-based perfect absorber based on the critical coupling with guided resonance is proposed. By using the finite-difference time-domain (FDTD) simulations, a complete absorption peak is achieved at the wavelength of 1310 nm. Moreover, we have compared the simulation results with theoretical calculations, which agree well with each other. By changing related structural parameters, the wavelength of absorption peak can be tuned effectively. Furthermore, the proposed absorber can tolerate a relatively wide range of incident angles and demonstrate polarization-independence. In addition to (CH3NH3)PbI3, the complete optical absorption in the other halide perovskites can be realized by the same mechanism.

Investigations on the enhanced photocatalytic activity of (Ag, La) substituted nickel cobaltite spinels

This work reports the synthesis of NiCo2O4 (NCO), Ni0.95Ag0.05Co2O4 (NACO), and Ni0.95Ag0.05Co1.95La0.05O4 (NACO) by a simple sol-gel route and the evaluation of their photocatalytic activity towards the organic dye Evans blue. The synthesized photocatalysts were characterized by analytical techniques such as XRD, FTIR, SEM, particle analyzer and UV–Vis spectroscopy. The XRD patterns proved that the prepared samples crystallized in the cubic spinel structure. The related structural parameters were also evaluated. The SEM micrographs revealed that all the samples possessed agglomerated uneven structure. The particle size was found to decrease with the addition of dopants. The photocatalytic efficiency was validated using UV–vis spectroscopy, which proved the relatively narrow bandgap of the spinels. The photocatalytic activity of the undoped and doped samples against the Evans blue dye under visible light irradiation has been systematically studied. The superior photocatalytic activity was witnessed for (Ag, La) co-doped NiCo2O4. Conclusively, a possible mechanism for the photo-degradation of the dye was established. Hence rare earth doped cobaltites serve as a potential candidate for resolving the crucial environmental pollution.

On the structural, optical and electrical properties of Cu2+ doped Zn0.94Cd0.06O nanomaterials

Nanoparticles of Cu2+ doped Zn0.94Cd0.06O oxide with formula Zn0.94Cd0.06-xCuxO [x = 0.0, 0.03, 0.05] were prepared via sol-gel auto combustion (SGAC) method at pH value of 10. Room temperature X-ray powder diffraction (XRD) patterns confirms that all the synthesized samples were single-phased polycrystalline with wurtzite hexagonal structure (P63mc). Crystallite size is estimated from XRD which was found to be 29–40 nm. Using Rietveld refinement of XRD data, the structure, space group and other structure related parameters were confirmed. The nanoparticle formation was confirmed via field emission scanning electron microscopy (FE-SEM) and elemental composition was verified through energy dispersive analysis of X-rays (EDAX). Raman spectroscopy reveals seven active phonon modes for both pristine Zn0.94Cd0.06O and Zn0.94Cd0.06-xCuxO [x = 0.03, 0.05]. The oxide formation is also conveyed through Fourier transformation of Infra-red (FTIR) spectroscopy. The bandgap using UV–Vis spectroscopy was found to be about 3.02 eV and 3.09 eV for Zn0.94Cd0.06-xCuxO (x = 0.03, 0.05), 3.14 eV for pristine Zn0.96Cd0.06O. The dielectric studies confirmed high dielectric constant for Zn0.94Cd0.06O that decreases gradually on increasing Cu2+ doping concentration. The impedance analysis of all samples shows non-Debye character with spread of relaxation times.

The effects of Mn and/or Ni dopants on the in vitro/in vivo performance, structural and magnetic properties of β-tricalcium phosphate bioceramics

The present study describes the effects of dopants of Mn and/or Ni on the structural, magnetic and in vivo/in vitro performances of β-tricalcium phosphate (β-TCP) bioceramics synthesized by a sol-gel method. Both types of dopants caused significant effects on the structure-related parameters of β-TCP, including the crystallite dimensions and lattice parameters. The magnetic properties of as-prepared samples were found to be affected by the type and amount of the dopant(s). The in vitro antimicrobial activities of doped β-TCPs against American Type Culture Collection (ATCC) reference bacterial and fungal strains were evaluated. Among them, only 1.35Ni-TCP displayed an effective antimicrobial activity against Gram-positive bacteria (50 μg/mL Minimum Inhibitory Concentration (MIC) range), while other types of doped β-TCPs did not possess with such effect. The in vivo tests showed that each formulation could be a good nominate for bone healing and bone treatment.

Dual-band near-perfect metamaterial absorber based on cylinder MoS[formula omitted]-dielectric arrays for sensors

As a two-dimensional (2D) material, the crystalline monolayer molybdenum disulfide (MoS2) has drawn extensive attention due to its interesting optical, mechanical and thermal properties compatible with many applications. Here, a dual-band perfect metamaterial absorber (PMA) composed of a simple periodically patterned cylinder/square MoS2-dielectric silica (SiO2) arrays supported by a metal ground plane is proposed and studied by using finite-difference time-domain (FDTD) simulations. Numerical results reveal that the absorption spectrum of the MoS2-based structure displays two perfect absorption peaks in the visible–NIR region. The interactions between electromagnetic waves and this PMA structure are analyzed through the field distributions and spectral responses in detail. It is also presented that the peak wavelengths can be tuned by manipulating related structural parameters. Compared with previous dual-band PMA, our absorber has only one shape that can greatly simplify the manufacturing process and the absorber is insensitive to the polarization of incident light. Furthermore, this PMA can work as a refractive index sensor with high performance due to its stable near-unity absorption.

Luminescence of Sb3+ in closed shell transition metal oxides

The spectroscopic activity of Sb3+ is investigated at 77 K in CaTiO3, CaZrO3, SrZrO3, YNbO4, SrNb2O6 and M'-YTaO4. The data are interpreted in the frame of a Sb3+-to-transition metal (Mn+) charge transfer process that is formalized on the basis of a semi-empirical equation involving the energy of the corresponding electronic transition, the electronegativity of Sb3+ (the electron donor) and of Mn+ (the electron acceptor) and crystal structure-related parameters.

Optimization of Cutting Parameters for Milling TC4 Materials with Spiral Corn Milling Cutter

To solve the problem of spiral corn milling cutting TC4 material force inequality and low efficiency, single blade model and cutting force model of spiral corn milling cutter were both analyzed in this paper. By using AdvantEdge FEM software to set the related corn mill cutter blade structure parameters, blade parameters, and network partition, etc. we got the in-process cutting force and temperature simulation figure of spiral corn milling cutter while processing, and on the basis of these simulation parameters, process verification is conducted. The result shows that the analysis of the milling force of spiral corn milling cutter may optimize the cutting parameters, improve the efficiency of difficult-to-machine materials and reduce the tool wear of the cutters while processing TC4 materials.

Polarization-insensitive and wide-angle broadband absorption enhancement of molybdenum disulfide in visible regime.

In order to remarkably enhance the absorption capability of monolayer molybdenum disulfide (MoS2), a broadband MoS2-based perfect absorber, which is inspired by metamaterial, is proposed. By using the finite-difference time-domain (FDTD) simulations, the absorption of proposed MoS2-based absorber above 94% is achieved from 594 to 809 nm. Meanwhile, the average absorptions of monolayer MoS2 enhanced up to 27% and 67% are realized from 598 to 671 nm and 710 to 801 nm, respectively. By manipulating related structural parameters, the absorption spectrum can be further broadened and shifted in a wide wavelength range. Furthermore, the proposed absorber can tolerate a relatively wide range of incident angles and demonstrate polarization-independence.

Strong impact of LiNbO3 fillers on local electromechanical and electrochemical properties of P(VDF-TrFe) polymer disclosed via scanning probe microscopy

In this work, we demonstrate an alteration of mechanical, electrophysical, piezo- and ferroelectric properties of polyvinylidene fluoride/trifluoroethylene P(VDF-TrFE) copolymer at the composition of 70/30 mol% in the presence of lithium niobate (LiNbO3) fillers. The micro- and nanoscale measurements of the elastic modulus suggest a two-fold increase in the mechanical rigidity of the P(VDF-TrFE) film after embedding the LiNbO3. The enhancement of local piezo- and ferroelectric properties of the modified polymer is evidenced by the increase of the direct piezoelectric coefficient from 27.1 pm/V to 36.1 pm/V. This increase is supposed to be associated with a significant contribution from Li-ion diffusion (the surface nanoelectrochemistry effect). This suggestion is supported by the observation of irreversible dc bias voltage-induced Li-ion extraction contributing to the locally-measured piezoresponse. The dynamics of the Li-ion diffusion, studied by electrochemical strain time spectroscopy, shows a decrease of the diffusion coefficient for an area poled by dc bias voltage as compared with a pristine one. This decrease confirms the existence of irreversible electrochemical processes during the local piezoelectric measurements. At the same time, X-ray diffraction and micro-Raman data suggest the integrity of the intramolecular structure of the P(VDF-TrFE) copolymer after embedding the LiNbO3 fillers. This is a key achievement allowing to keep the structure-related parameters specific to the pure P(VDF-TrFE) copolymer. The obtained results reveal a crucial role of the fillers in attaining the desired functional behavior, thus paving the way towards the development of advanced sensors, transducers, actuators, and piezoelectric devices.

Ag Nanocrystals with Nearly Ideal Optical Quality: Synthesis, Growth Mechanism, and Characterizations.

Though Ag nanocrystals are predicted to be the best material for localized surface plasmon resonances (LSPR) in the visible light region, realization of their ideal LSPR properties is hindered by the stringent requirements: i.e., simultaneous control of their size, shape, crystallinity, and surface structure. To achieve this goal, a synthetic scheme in non-polar solvent coupled with mild oxidative etching by H+ ions has been established. With a trace amount of Cl- ions as catalysts, H+ ions (in the form of carboxylic acids) become active for selectively etching the nuclei (and small nanocrystals) with imperfect crystal structure, which results in a new growth mechanism for formation of monodisperse nanocrystals, namely "self-focusing of size/crystallinity distribution". H+ ions, ligands, and other reagents in the scheme are confirmed to possess negligible effects on the surface dielectric properties of Ag nanocrystals. To eliminate radiative damping of LSPR, single-crystalline and monodisperse spherical Ag nanocrystals in the size range between 7 and 20 nm are synthesized using this one-pot scheme. With excellent control of all related structural parameters, the full width at half-maximum of LSPR spectra of single-crystalline Ag nanocrystals match theoretical predictions in the entire size range, and the maximum quality factor (∼20) of LSPR predicted by theory is realized. The Raman enhancement factor of the single-crystalline Ag nanocrystals for crystal violet (excitation at 514 nm) is 5 times higher than that of the typical multi-twinned nanocrystals with the same size.

Rare-Earth-Doped Ceria Systems and Their Performance as Solid Electrolytes: A Puzzling Tangle of Structural Issues at the Average and Local Scale.

Rare-earth (RE)-doped ceria systems, in particular when RE ≡ Nd, Sm, or Gd, are well-known to be characterized by high values of ionic conductivity in the intermediate temperature range, which, in principle, makes them ideal solid electrolytes in solid oxide fuel and electrolysis cells. Defect chemistry turns out to be a pivotal issue in this framework because ionic conductivity is driven by the ability of oxygen vacancies to move through the lattice, and any form of defect clustering tends to depress the efficiency of oxygen transport. In this viewpoint, not only are factors at the average scale assessed, such as the compositional extent of the CeO2-like solid solution, but also the occurrence of local inhomogeneities due to vacancy-dopant association is discussed in correlation with its central role in hindering the migration of vacancies. The relationship between the stability of the hybrid phase and the RE3+ ionic size is presented, and the highly complementary role of Raman spectroscopy toward X-ray diffraction is described in detail. The key points of the whole discussion are finally used to identify the most relevant structure-related parameters affecting ionic conductivity in the studied material.

Antibacterial Activity and Mechanism of Action of Bovine Lactoferricin Derivatives with Symmetrical Amino Acid Sequences.

In recent years, the overuse of antibiotics has become very serious. Many pathogenic bacteria have become resistant to them, with serious potential health consequences. Thus, it is urgent that we develop new antibiotic drugs. Antimicrobial peptides (AMPs) are important endogenous antibacterial molecules that contribute to immunity. Most have spectral antibacterial properties and do not confer drug resistance. In this paper, an 11-residue peptide (LFcinB18–28) with a sequence of KCRRWQWRMKK was modified by amino acid substitution to form a symmetrical amino acid sequence. The antibacterial activities and mechanisms of action of engineered peptides including KW-WK (KWRRWQWRRWK), FP-PF (FPRRWQWRRPF), FW-WF (FWRRWQWRRWF), and KK-KK (KKRRWQWRRKK) were investigated. The four engineered peptides could more effectively inhibit bacteria than the original peptide, LFcinB18–28. This suggested that a symmetrical amino acid sequence might enhance the antibacterial activity of AMPs. However, only peptides KW-WK, FP-PF, and KK-KK were safe; FW-WF displayed hemolytic activity. The engineered peptides shared cationic and amphipathic characteristics that facilitated interactions with the anionic microbial membranes, leading to disruption of membrane integrity and permeabilizing microbial membranes, resulting in cell death. Therefore, a symmetrical amino acid sequence and related structural parameters offer an alternative approach to the design of AMPs. This will provide a scientific basis for the design and synthesis of new AMPs.

Computer-based automatic classification of trabecular bone pattern can assist radiographic bone quality assessment at dental implant site.

To develop and validate an automated classification method that determines the trabecular bone pattern at implant site based on three-dimensional bone morphometric parameters derived from CBCT images. 25 human cadaver mandibles were scanned using CBCT clinical scanning protocol. Volumes-of-interest comprising only the trabecular bone of the posterior regions were selected and segmented for three-dimensional morphometric parameters calculation. Three experts rated all bone regions into one of the three trabecular pattern classes (sparse, intermediate and dense) to generate a reference classification. Morphometric parameters were used to automatically classify the trabecular pattern with linear discriminant analysis statistical model. The discriminatory power of each morphometric parameter for automatic classification was indicated and the accuracy compared to the reference classification. Repeated-measures analysis of variances were used to statistically compare morphometric indices between the three classes. Finally, the outcome of the automatic classification was evaluated against a subjective classification performed independently by four different observers. The overall correct classification was 83% for quantity-, 86% for structure-related parameters and 84% for the parameters combined. Cross-validation showed a 79% model prediction accuracy. Bone volume fraction (BV/TV) had the most discriminatory power in the automatic classification. Trabecular bone patterns could be distinguished based on most morphometric parameters, except for trabecular thickness (Tb.Th) and degree of anisotropy (DA). The interobserver agreement between the subjective observers was fair (0.25), while the test-retest agreement was moderate (0.46). In comparison with the reference standard, the overall agreement was moderate (0.44). Automatic classification performed better than subjective classification with a prediction model comprising structure- and quantity-related morphometric parameters. Computer-aided trabecular bone pattern assessment based on morphometric parameters could assist objectivity in clinical bone quality classification.

Doping induced effect on optical and band structure properties of Sr2Si5N8 based phosphors: DFT approach

Nitrido silicates are emerged as highly efficient luminescent materials (phosphors) that found considerable industrial application as white light emitting diodes (LEDs) have been studied with respect to band structure and related electronic structure parameters. They have tunable optical properties, as the band gap is of indispensable because it determines both the electrical and optical features of the material, which can be varied by the material composition (by doping technique). It is found also that the nitride (alumo) silicates “Sr2Si5N8: Eu2+” have wide industrial application as highly efficient red-emitting phosphor materials in pc-LEDs. In this report we apply density functional theory (DFT) within the GGA+U approach to study the structural, electronic and optical properties of Eu2+ and Ce3+ doped Sr2Si5N8. The total energy has been optimized as a function of the unit cell volume. Electronic structure including, the electronic density of state (DOS), the band structure and the linear optical susceptibility are calculated for the relaxed structure applying the optimized lattice constant. The calculated optical dispersion of dielectric susceptibility are closely related to the corresponding electronic structure and our results are in very good agreement with experimental data.

Theory of microstructured polymer–electrolyte artificial muscles

Ionic electroactuator beams are promising systems for artificial muscles in microrobotics. Here a theory is developed to investigate one promising class of such systems, which employs flexible volume-filling electrodes impregnated with polymer–electrolyte. The theory provides analytical formulae for the equilibrium beam curvature as a function of voltage and structure-related operational parameters. It predicts a possible enhancement of beam curvature by orders of magnitude over that of flat electrodes. Volume-filling electrodes thus constitute one of the ‘strongest’ architectures for voltage-induced movement. Approximate expressions for the dynamics of tandem pore charging and beam deflection are developed to determine the maximum pore length that still warrants a sufficiently fast response time (up to 1 s). Upper bounds on applied voltage and response time constrain the maximal device thickness and curvature, and therefore, the resulting work such a device can perform.

Enhancement of absorption of molybdenum disulfide monolayer on low-index contrast dielectric grating in the visible regions

A design consists of low-index contrast grating is proposed to achieve the narrow absorption response for two-dimensional (2D) materials such as a MoS2 monolayer in the visible wavelength regime. High absorption occurs at the wavelength of Fano resonance for both transverse dielectric (TE) and transverse magnetic (TM) polarizations. It is proved that by manipulating related structural parameters and the incident angle, the peak wavelengths of MoS2 absorption can be tuned in a wide range. In addition, an improved structure with MoS2 ribbons is proposed to further boost the light-MoS2 interaction. The relationships between the absorptance and the period and width of MoS2 ribbons are discussed. The proposed optical devices could be efficiently exploited as tunable absorbing structures for optoelectronics and photovoltaic devices in the visible region.

Effect of Sea Level Rise and Offshore Wave Height Change on Nearshore Waves and Coastal Structures

In 1994, Townend proposed a method to calculate the relative changes in various wave characteristics and structure-related parameters due to sea level rise for regular waves. The method was extended to irregular waves by Cheon and Suh in 2016. In this study, this method is further extended to include the effect of future change in offshore wave height and the sea level rise. The relative changes in wavelength, refraction coefficient, shoaling coefficient, and wave height in nearshore area are presented as functions of the relative changes in water depth and offshore wave height. The calculated relative changes in wave characteristics are then used to estimate the effect of sea level rise and offshore wave height change on coastal structures by calculating the relative changes in wave run-up height, overtopping discharge, crest freeboard, and armor weight of the structures. The relative changes in wave characteristics and structure-related parameters are all expressed as a function of the relative water depth for various combinations of the relative changes in water depth and offshore wave height.