Orbital Method Research Articles

A conjecture about characters of finite pattern groups

Inspired by Kirillov's orbital method, we propose a conjecture (Conjecture 1.7), which suggests an explicit and exhaustive construction of characters for finite pattern groups via coadjoint orbits. First, we establish the construction for irreducible characters of degree q for finite pattern groups. Second, we verify the conjecture for the case of finite pattern groups contained in U4(Fq), where Un stands for the full unitriangular group of rank n. Finally, we classify irreducible characters for Gn(Fq), a generalization of Heisenberg group, where Gn is the pattern subgroup of Un, associated to the closed set{(1,m),(k,n),(i,n+1−i)|1<m,k<n,1⩽i⩽[n2]},3⩽n∈N. Hence Conjecture 1.7 and the analogous conjectures of Higman, Lehrer and Isaacs holds for Gn(Fq).

Spectral mapping of zeolite bearing paleolake deposits at Lake Tecopa, California and its implications for mapping zeolites on Mars

• Zeolitic tuff at paleolake Tecopa investigated using in-situ and orbital methods. • Reasons for limited orbital detections of zeolites in paleolake. • Importance of ground investigation to interpreting orbital data. While non-analcime zeolites are plausible mineral constituents of the Martian surface, their lack of prominent spectral characteristics in the visible to shortwave infrared wavelength region makes them difficult to identify using orbital data. This lack of detection has led to the assumption that they are limited or absent. Here we assess the capability of mapping non-analcime zeolites using different mapping techniques and present the possible reasons that could lead to limited detection of zeolites using an analog study from Paleolake Tecopa, California. We used spaceborne hyperspectral Hyperion and multispectral ASTER data to identify zeolites following X-ray Diffraction (XRD) and visible-near infrared and shortwave infrared (VNIR-SWIR) spectral analysis of collected samples containing zeolites and other associated minerals. We used four of the most common spectral mapping methods: (1) band ratios, (2) minimum noise fraction (MNF), (3) spectral angle mapper (SAM), and (4) linear spectral unmixing (LSU). We were able to map zeolite-rich tuff beds using carefully selected band indices, MNF band combinations, and the pixel spectra corresponding to a zeolite-rich abandoned quarry area. Hyperion results show less overall accuracy than the ASTER image products mostly due to the low signal-to-noise ratio of the Hyperion data. The spectral characteristics of zeolites in zeolite-rich pixels are masked by phyllosilicates (e.g., smectite) present in the ground resolution cell (GRC), making it difficult to identify zeolites in phyllosilicate-bearing deposits solely based on zeolite spectra. Therefore, the SAM product derived using the pixel spectrum of the well-exposed zeolite-rich quarry shows the highest accuracy in Hyperion image products. ASTER band ratio Band 2/Band 1, representing the ferric ion, was able to identify the zeolite-rich beds with the highest accuracies. However, most of the zeolite-rich paleolake beds were difficult to identify since they are buried by other beds, mixed with other beds due to physical weathering, or the areas of exposed beds are smaller than the GRC of the satellite. The results imply that the paucity of detected zeolites on Mars, as we see at Lake Tecopa, does not preclude their wider presence, either beneath other materials, obscured by surface dust, or mixed with more spectrally dominant phases. :

Quantum chemical, spectroscopic and molecular docking investigations of potential pulmonary fibrosis drug methyl 2-chloro 4-iodonicotinate.

In this work, the methyl 2-chloro 4-iodonicotinate (MCIN) was investigated to study the structural, spectroscopic and electronic properties using density functional theory (DFT) quantum chemical calculations. The most stable structure of MCIN was optimized by DFT/B3LYP method with a LanLD2Z basis set. The optimized parameters and vibrational wavenumbers were determined. The vibrational task of the molecule was done by potential energy distribution calculations. The 13 C NMR spectrum of the MCIN molecule was simulated by the Gauge-Invariant-Atomic Orbital method using a dimethyl sulfoxide solution and the isotropic chemical shift values of the molecule were calculated and observed. Ultraviolet-visible spectra were simulated and observed. The pharmaceutical activity was predicted using frontier molecular orbital and natural bond orbital analysis. The reactive sites of the MCIN molecule were determined using Mulliken atomic charge distribution, molecular electrostatic potential surface and the local reactivity analysis. The molecular docking analysis confirms that the title molecule can be used in drug design for the treatment of pulmonary fibrosis.

Orbit method and dual topology for certain Lie groups

Orbit method and dual topology for certain Lie groups

Theoretical comparison of real-time feedback-driven single-particle tracking techniques.

Real-time feedback-driven single-particle tracking is a technique that uses feedback control to enable single-molecule spectroscopy of freely diffusing particles in native or near-native environments. A number of different real-time feedback-driven single-particle tracking (RT-FD-SPT) approaches exist, and comparisons between methods based on experimental results are of limited use due to differences in samples and setups. In this study, we used statistical calculations and dynamical simulations to directly compare the performance of different methods. The methods considered were the orbital method, the knight's tour (grid scan) method, and MINFLUX, and we considered both fluorescence-based and interferometric scattering (iSCAT) approaches. There is a fundamental trade-off between precision and speed, with the knight's tour method being able to track the fastest diffusion but with low precision, and MINFLUX being the most precise but only tracking slow diffusion. To compare iSCAT and fluorescence, different biological samples were considered, including labeled and intrinsically fluorescent samples. The success of iSCAT as compared to fluorescence is strongly dependent on the particle size and the density and photophysical properties of the fluorescent particles. Using a wavelength for iSCAT that is negligibly absorbed by the tracked particle allows for an increased illumination intensity, which results in iSCAT providing better tracking for most samples. This work highlights the fundamental aspects of performance in RT-FD-SPT and should assist with the selection of an appropriate method for a particular application. The approach used can easily be extended to other RT-FD-SPT methods.

Rare earth metal‐doped Zintl phase thermoelectric materials: The Yb5−xRExAl2Sb6 (RE=Pr, Nd, Sm) system

AbstractThree Zintl phase solid solutions in the Yb5 − xRExAl2Sb6 (RE = Pr, Nd, Sm) system have successfully been synthesized by arc melting followed by annealing. The isotypic crystal structure of these compounds was characterized by PXRD and SXRD analyses, and their Ca5Al2Bi6‐type structure (space group Pbam, Z = 2) was described as a combination of (1) the 3‐dimensional anionic [Al2(Sb4Sb4/2)] frameworks and (2) the space‐filling cations Yb2+ and RE3+ located in between the anionic frameworks. In particular, the anionic frameworks were originally built from the two neighboring tetrahedral [AlSb4] moieties via the Sb1‐Sb1 bridges. The site‐preference of RE3+ for the Yb3/RE‐site with the mixed occupation ratio between ca. 9% and 16% of RE3+ was elucidated by the size‐factor criterion based on the size match between the cationic size and the site volume. The band structures, density of states, and crystal orbital Hamilton population curve analyses were conducted by the tight‐binding linear muffin‐tin orbital method, and the results proved that the RE3+‐doping increased the band degeneracies and the number of resonance peaks near the Fermi level resulting in the improved Seebeck coefficients. The electrical transport property measurements proved that despite the successful addition of n‐type RE3+ dopants in the title Yb5 − xRExAl2Sb6 system, the electrical conductivity decreased due to the canceling off of the newly added n‐type carriers by the already existing p‐type carriers resulting in still the p‐type character. However, the enhanced Seebeck coefficients predicted by the increased effective mass from the DFT calculations eventually improved the overall power factor of the RE3+‐doped title compounds.

Karakteristik Klinis Pasien Laserasi Kelopak Mata Akibat Trauma di Pusat Mata Nasional Rumah Sakit Mata Cicendo

Introduction : Trauma of eyelids due to sharp object, blunt object, road traffic accidents etc. are the major causes resulting in injuries to eyelids. A good identification and prompt treatment can improve the outcome of palpebral laceration. Purpose : To describe clinical characteristics of eyelids laceration due to trauma without involvement of lacrimal system and other orbital Methods : A retrospective descriptive cross sectional study was conducted. Data is taken from medical records of patients diagnosed as eyelid laceration from January 2016 to November 2020. Age, gender, laterality, first reference, place, onset, cause, site of trauma, depth, outcome, complication and System for Peri-Ocular Trauma (SPOT) classification was reviewed. Results : This study comprised of total 157 patients. Most of them were males 119 (75.80%) with median of age 24. The main mechanism of injury was direct trauma 88 (56.05%). The location where the injury occured was road side accidents 81 (51.59%). Superior eyelid was the most affected 96 (61.15%). Subcutaneus tissue as wound base 68 (43.31%) and affected to margin of eyelid 36 (22.92%). Hypertropic scar was the most complication found in 40 (25.47%). The most common SPOT type injury were Type IA. Conclusion : Eyelids laceration due to trauma is common in male productive age, mainly affecting superior palpebra, mostly because of road side accidents. Hypertropic scar was most complication beside traumatic ptosis, lagophthalmos and lid margin notching. The SPOT classification can simplify a recording of palpebral injuries.

Comparison of the Effectiveness of Selected Vibration Signal Analysis Methods in the Rotor Unbalance Detection of PMSM Drive System

Mechanical unbalance is a phenomenon that concerns rotating elements, including rotors in electrical machines. An unbalanced rotor generates vibration, which is transferred to the machine body. The vibration contributes to reducing drive system reliability and, as a consequence, leads to frequent downtime. Therefore, from an economic point of view, monitoring the unbalance of rotating elements is justified. In this paper, the rotor unbalance of a drive system with a permanent magnet synchronous motor (PMSM) was physically modelled using a specially developed shield, with five test masses fixed at the motor shaft. The analysed diagnostic signal was mechanical vibration. Unbalance was detected using selected signal analysis methods, such as frequency-domain methods (classical spectrum analysis FFT and a higher-order bispectrum method) and two methods applied in technical diagnostics (order analysis and orbit method). The efficiency of unbalance symptom detection using these four methods was compared for the frequency controlled PMSM. The properties of the analysed diagnostic methods were assessed and compared in terms of their usefulness in rotor unbalance diagnosis, and the basic features characterizing the usefulness of these methods were determined depending on the operating conditions of the drive. This work could have a significant impact on the process of designing diagnostic systems for PMSM drives.

Periodicity of Superatomic Hybrid Orbitals in Substituted Superatoms and Superatomic-like X@Ga12 (X = Li~Kr) Clusters

A superatom is a cluster composed of a specific number of atoms. We recently found that the superatom-like X@Ga12 (X = Li~Kr) clusters has the periodic energy levels of the specific orbitals 2S and 2P by means of the DV-Xα molecular orbital calculation method. This periodicity in energy levels has not been seen in 1D or 1F orbitals. We supposed that the periodicity of the energy levels of the 2S and 2P superatomic-like orbitals come from the same symmetry between atomic orbitals as the central atom X and the surrounding specific orbitals, according to the Jellium model. Both the s and p atomic orbitals of the central atom X in the superatom-like X@Ga12 have a large shielding effect, suggesting that the s and p atomic orbitals interact strongly with both 2S and 2P superatomic-like orbitals. The energy level periodicity has the potential to periodically change the number of electrons located in the 1D and 1F orbitals, which is related to magnetic properties and is expected to be useful for novel magnetic devices by periodically controlling the magnetism of superatoms.

Molecular Structure, Spectroscopic Assessment, PDOS, Topology Evaluation and Docking Studies of 2-Chloro-5-nitrobenzophenone

The vibrational, electronic properties of 2-chloro-5-nitrobenzophenone (2C5NB) are explored experimentally, and theoretically (DFT) using B3LYP functional with LanL2DZ basis set. This has been performed for assignment vibrational frequencies that conjointly involves inserting beneficial evidence concerning the structure of the chosen compound. Based on PED, a comprehensive clarification of the FT-Infrared and FT-Raman spectra of the designated molecule were documented, with these studies agreeing satisfactorily with the experimental data. By mapping the total electron density isosurface with MEP, and contour map, charge density distribution and chemical reactivity spot of the 2C5NB were studied. Molecule stability ascending from hyper conjugative interactions and charge delocalization were explored using NBO analysis. For energies, the HOMO-LUMO diagram has been depicted. The transitions of the compound expression is (n→π*) in the UV-Vis region. The chemical changes of the molecule in 1H and 13C nuclear magnetic resonance were measured using the Gauge-Independent Atomic Orbital (GIAO) method and analysed using 1H and 13C NMR spectra. The non-zero value of μ and elevated β worth specify that the 2C5NB might be a good candidate for NLO content. In order to explore the simultaneous correlations of the different bonds of the 2C5NB, the total and partial DOS spectrum were intricated. Fukui functions were made to treasure the reactive site all over the molecule. The thermodynamic properties have been accomplished. The docking of molecule studies disclosed that the 2C5NB molecule performances a central role in binding proteins that inhibit L-glutamate oxidase. Minimum binding energy and intermolecular energy is perceived in the interaction.

Electronic structure of short-period ZnSe/ZnTe superlattices based on DFT calculations

In the present study we discuss the effect of variation in the number of monolayers n on the electronic and optical properties of superlattices (SLs) (ZnSe)n/(ZnTe)n. The total energies were calculated by the full-potential linear muffin-tin orbital (FP-LMTO) method, and the exchange-correlation energy was applied in the local density approximation (LDA). First, the calculations show a decrease in the derivative of bulk modulus and electronic bandgap with an increase in the number of monolayers n. Second, the radiation energies up to 15 eV, the dielectric function ε(ω), the refractive index n(ω), and the reflectivity R(ω) are studied. These calculations may be beneficial to understand the properties of short-period superlattices (ZnSe)n/(ZnTe)n.

Theoretical Insights into the Intermolecular Hydrogen Bond Effect on ESIHT Process in 2′-Hydroxychalcone: A Combined DFT/TDDFT Study

Present computational study lighting up the ground and excited states properties of 2′-hydroxychalcone (2′-HC) and 2′-HC + (H2O)2-[2′-HCH] molecules by employing density functional theory (DFT) and time-dependent density functional theory (TD-DFT). Furthermore, micro-solvation, hydrogen bond dynamics and natural charge analysis studies have been done for both molecules at ground/excited states by using effective fragment potential (EFP1)/natural bond orbital (NBO) methods at 6-31G(d,p)/B3LYP level. The excited state intra-molecular hydrogen atom transfer (ESIHT) mechanism of 2′-HC was investigated via potential energy scans (PES). No hydrogen atom transfer is observed in the S3 state of 2′-HC and S1/S3 states of 2′-HCH. The optimized molecular structures, molecular orbital’s and electrostatic potential maps were depicted along with UV-Vis absorption spectra. Good consistency between experimental and computational absorption wavelength for a 2′-HC molecule with methanol as solvent.

Color Energy of Some Cluster Graphs

Let $G$ be a simple connected graph. The energy of a graph $G$ is defined as sum of the absolute eigenvalues of an adjacency matrix of the graph $G$. It represents a proper generalization of a formula valid for the total $\pi$-electron energy of a conjugated hydrocarbon as calculated by the Huckel molecular orbital (HMO) method in quantum chemistry. A coloring of a graph $G$ is a coloring of its vertices such that no two adjacent vertices share the same color. The minimum number of colors needed for the coloring of a graph $G$ is called the chromatic number of $G$ and is denoted by $\chi(G)$. The color energy of a graph $G$ is defined as the sum of absolute values of the color eigenvalues of $G$. The graphs with large number of edges are referred as cluster graphs. Cluster graphs are graphs obtained from complete graphs by deleting few edges according to some criteria. It can be obtained on deleting some edges incident on a vertex, deletion of independent edges/triangles/cliques/path P3 etc. Bipartite cluster graphs are obtained by deleting few edges from complete bipartite graphs according to some rule. In this paper, the color energy of cluster graphs and bipartite cluster graphs are studied.

Effect of the Altitudes and Eccentricity of the Initial Orbit on Satellite Transition Efficiency

This research dealt with choosing the best satellite parking orbit and then the transition of the satellite from the low Earth orbit to the geosynchronous orbit (GEO). The aim of this research is to achieve this transition with the highest possible efficiency (lowest possible energy, time, and fuel consumption with highest accuracy) in the case of two different inclination orbits. This requires choosing a suitable primary parking orbit. All of the methods discussed in previous studies are based on two orbits at the same plane, mostly applying the circular orbit as an initial orbit. This transition required the use of the advanced technique of the Hohmann transfer method for the elliptical orbits, as we did in an earlier research, namely the transition from the perigee of the initial orbit to the final orbit and then conducting the rotation of the orbit plane to match the plane for the desired final orbit.&#x0D; The effect of the perigee altitude of the initial orbit on the transition efficiency calculated for the values ​​between 300 to 3000 km. It was found that increasing the altitude reduces the energy and fuel needed for transportation, but the time required for transportation increases, into account that the increased height of the initial or parking orbit also implies the requirement of higher energy to reach it.&#x0D; The effects of eccentricity (e) values of the initial orbit between 0.01 to 0.2 on the transition efficiency were calculated. It was found that the increase in (e) reduces the energy and fuel, but does not affect the time, required for transportation.

Discovery of potential inhibitors against New Delhi metallo-\u03b2-lactamase-1 from natural compounds: in silico-based methods

New Delhi metallo-β-lactamase variants and different types of metallo-β-lactamases have attracted enormous consideration for hydrolyzing almost all β-lactam antibiotics, which leads to multi drug resistance bacteria. Metallo-β-lactamases genes have disseminated in hospitals and all parts of the world and became a public health concern. There is no inhibitor for New Delhi metallo-β-lactamase-1 and other metallo-β-lactamases classes, so metallo-β-lactamases inhibitor drugs became an urgent need. In this study, multi-steps virtual screening was done over the NPASS database with 35,032 natural compounds. At first Captopril was extracted from 4EXS PDB code and use as a template for the first structural screening and 500 compounds obtained as hit compounds by molecular docking. Then the best ligand, i.e. NPC120633 was used as templet and 800 similar compounds were obtained. As a final point, ten compounds i.e. NPC171932, NPC100251, NPC18185, NPC98583, NPC112380, NPC471403, NPC471404, NPC472454, NPC473010 and NPC300657 had proper docking scores, and a 50 ns molecular dynamics simulation was performed for calculation binding free energy of each compound with New Delhi metallo-β-lactamase. Protein sequence alignment, 3D conformational alignment, pharmacophore modeling on all New Delhi metallo-β-lactamase variants and all types of metallo-β-lactamases were done. Quantum chemical perspective based on the fragment molecular orbital (FMO) method was performed to discover conserved and crucial residues in the catalytic activity of metallo-β-lactamases. These residues had similar 3D coordinates of spatial location in the 3D conformational alignment. So it is posibble that all types of metallo-β-lactamases can inhibit by these ten compounds. Therefore, these compounds were proper to mostly inhibit all metallo-β-lactamases in experimental studies.

13C NMR chemical shifts in substituted benzenes: analysis using natural perturbation orbitals and substitution effects

The natural perturbation orbital (NPO) method, combined with the gauge-including atomic orbital (GIAO), was applied to nuclear magnetic resonance (NMR) chemical shifts. The substituent effects of electron-donating (NH2) and electron-withdrawing (NO2) groups on the 13C NMR chemical shifts of monosubstituted benzenes were analysed using NPOs. 13C chemical shifts at the ortho-, meta- and para-positions were efficiently decomposed into contributions from two NPO pairs (, ). These contributions were further divided into two factors, namely electron density in the vicinity of resonance nuclei and orbital energy gaps. Trends in the electron density matched with the ortho-, meta- and para-directions of the substituent effects. Specifically, NH2 shielded the ortho- and para-carbons, while NO2 deshielded the same carbons. The orbital energy gaps of ortho-carbons in NH2- and NO2-benzenes were significantly decreased, showing that these substituents shielded the ortho-carbons.

A first-principles investigation of band inversion in topologically nontrivial Na2AgX (X= As, Sb and Bi) full Heusler compounds

Topological nontrivial nature are the latest phases to be discovered in condensed matter physics with insulating bulk band gaps and topologically protected metallic surface states; they are one of the current hot topics because of their unique properties and potential applications. In this paper, we have highlighted a first-principles study of the structural stability and electronic behavior of the Na2AgX (X = As, Sb and Bi) full Heusler compounds, using the Full-Potential Linear Muffin-Tin Orbital (FP-LMTO) method. We have originated that the Hg2CuTi structure is appropriate in all studied materials. The negative values of the calculated formation energies mean that these compounds are energetically stable. The band structure is studied for the two cases relating the existence and the absence of spin-orbital couplings, where all materials are shown to be topologically non-trivial compounds. Spin orbital couplings were noticed to have no significant effect on the electronic properties such as the topological order.

Structural, electronic, elastic, magnetic and thermodynamic properties of Mn2LuZ (Z = B, Al, Ga and In) Heusler compounds: A first‐principle study

AbstractThe study of the structural, electronic, thermodynamic, elastic and magnetic properties of rare‐earth based full Heusler alloys Mn2LuZ (Z = B, Al, Ga and In) have been carried out using the full‐potential linearized muffin‐tin orbital method (FP‐LMTO), within density functional theory (DFT) and generalized gradient approximation (GGA) for exchange and correlation energy. The electronic properties studied have shown that the compounds have a metallic behavior. We have also computed the mechanical properties where we found these full Heusler compounds are mechanically stable. Using the quasi‐harmonic Debye model, the variations of bulk modulus, thermal expansion coefficient, heat capacities, Debye temperature and Gibbs free energy with pressures covering the 0–40 GPa interval and temperatures ranging from 0 to 1500 K were also investigated and in‐depth discussed. The calculated properties represent a solid prediction for the Mn2LuZ (Z = B, Al, Ga and In) Heusler compounds and are awaiting for experimental concretization.

Comparative in vitro and DFT antioxidant studies of phenolic group substituted pyridine-based azo derivatives

Two azo compounds 2-(3-pyridylazo)-3,5-dihydroxybenzoic acid (PAB) and 4-(3-pyridylazo)resorcinol (PAR) thought to have the potential to be used as antioxidants were designed, synthesized and antioxidant activities were investigated both in vitro and in silico. The synthesized compounds were characterized by 1H-NMR, 13C-NMR, FT-IR, UV-Vis and mass spectra. The molecular geometry and vibrational frequency calculations of the synthesized compounds in ground state were performed by the density functional theory (DFT) employing B3LYP level with the 6-311 G(d,p) basis set. The gauge independent atomic orbital (GIAO) method was used to determine the chemical shift values of 1H-NMR and 13C-NMR. HOMO–LUMO calculations were carried out by time-dependent DFT (TD-DFT) approach. Computational spectroscopic data of the synthesized compounds are fully compatible with experimental ones. The antioxidant activities of the PAB and PAR were investigated by using DPPH assay. It was determined that the PAB molecule showed better antioxidant activity than PAR and, butylated hydroxytoluene (BHT) which is the standard antioxidant. In addition, the thermodynamic stability parameters obtained with the help of DFT calculations were found to be quite compatible with the antioxidant capacity sequence derived from the DPPH assay. Highlights Two pyridine derivative azo compounds were synthesized and evaluated for its antioxidant activity Molecular geometry and spectroscopic properties of the molecules were calculated in vitro and in silico antioxidant activities were investigated by DPPH free radical scavenging assay The PAB molecule showed better antioxidant activity than BHT Communicated by Ramaswamy H. Sarma

First‐principles calculations to investigate structural stabilities, mechanical and optoelectronic properties of NbCoSn and NbFeSb half‐Heusler compounds

AbstractThe aim of this work was to study by means of the full potential linear muffin‐tin orbital method within generalized gradient approximation (GGA) and GGA + U approach the various physical properties of the NbCoSn and NbFeSb half‐Heusler compounds. The equilibrium ground states properties were calculated and compared with available experimental and theoretical data. The elastic constants have been calculated, and revealed that our compounds are mechanically stable. The obtained elastic modulus divulged that our compounds are elastically anisotropic and categorizing them as brittle compounds. The GGA approach showed a semi‐conductor nature. However, the GGA + U approach showed a significant improvement over other theoretical work. We remarked from the band structures that the two materials showed a p‐type semiconductor, with relatively high power factors. Furthermore, the optical quantities are calculated and discussed in detail. Hence, by our findings, the studied compounds could be used for thermoelectric and optoelectronic applications.