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The mechanical systems were modeled using various combinations of mass-damper-spring elements to analyze the system dynamics and improve the system stability. Due to the marginal stability property of the mass-damper rectilinear system, a proper control law is required to control the mass position accurately, improve the relative stability, and enhance the dynamical response. In this paper, a mathematical model of the electromechanical system was first derived and analyzed. Next, a digital PID controller was developed based on the root locus technique, and a systematic design procedure is presented in detail. The proposed digital control system was simulated in MATLAB and compared with other control schemes to check their tracking performance and transient response characteristics. In addition, the digital PID control algorithm of the mass-damper rectilinear system was implemented via dSPACE platform to investigate the real-time control system performance and validate the control design methodology. It has been shown that the digital PID controller yields zero percentage overshoot, fast transient response, adequate stability margins, and zero steady-state error. [ABSTRACT FROM AUTHOR]

Background: The surgical treatment of bony non-unions is traditionally performed with additional bone grafts when atrophic and/or stronger implants when hypertrophic. In the case of the clavicle shaft, however, in our experience, a more controversial method where no additional bone graft is needed leads to equally good consolidation rates, independent of the non-union morphology. This method requires the meticulous anatomical reconstruction of the initial fracture and fixation according to the AO principle of relative stability. Methods: A retrospective review following the STROBE guidelines was performed on a consecutive cohort of all patients who received surgical treatment of a midshaft clavicle non-union at the Medical Center of the University of Freiburg between January 2003 and December 2023. Patients were identified using a retrospective systematical query in the Hospital Information System (HIS) using the International Statistical Classification of Diseases and Related Health Problems Version 10 (ICD-10) codes of the German Diagnosis Related Groups (G-DRG). Two groups were formed to compare the consolidation rates of patients who received additional bone grafting from the iliac crest with those of patients who did not. A 3.5 mm reconstruction LCP plate was used in all patients. Consolidation rates were evaluated using follow-up radiographs and outcomes after material removal with a mean follow-up of 31.5 ± 44.3 months (range 0–196). Results: Final data included 50 patients, predominantly male (29:21); age: 46.0 ± 13.0 years, BMI 26.1 ± 3.7. Autologous bone grafts from the iliac crest were used in 38.0% (n = 19), while no bone addition was used in 62.0% (n = 30). Six patients were lost to follow-up. Radiological consolidation was documented after a mean of 15.1 ± 8.0 months for the remaining 44 patients. Consolidation rates were 94.4% (n = 17) in patients for whom additional bone grafting was used and 96.2% (n = 25) in patients for whom no graft was used. There was no relevant difference in the percentage of atrophic or hypertrophic non-unions between both groups (p = 0.2425). Differences between groups in the rate of consolidation were not significant (p = 0.7890). The complication rate was low, with 4.5% (n = 2). Conclusions: Independent of the non-union morphology, non-unions of the clavicle midshaft can be treated successfully with 3.5 mm locking reconstruction plates without the use of additional bone grafting in most cases. [ABSTRACT FROM AUTHOR]

In this paper, state space representation based approach to relative stability of Linear Time Invariant (LTI) systems is discussed. Specifically, given a bound on the output, relative Bounded Input-Bounded Output (BIBO) stability of LTI systems is discussed. The bound on dominant pole is first determined using input-output description of LTI system. Using state space representation of homogeneous (no external input) LTI system, the components of state vector are upper bound. The results are applied to Continuous Time Markov Chains (i.e. homogeneous stochastic linear systems). Finally, using state space representation of arbitrary (with external input) Linear Time Invariant systems, the location of dominant pole is bounded. Using the upper bound, the location of line (parallel to imaginary-axis jω and to the left of it) is utilized for determining relative stability. [ABSTRACT FROM AUTHOR]

Many conformers of 3-aminopropionitrile are known. Due to the biomedical importance of 3-aminopropionitrile a full investigation of structural, vibrational, and other associated properties of all possible conformers was performed. The geometrical structures, relative stability, and vibrational frequencies of the gauche and trans 3-aminopropionitrile conformers have been studied using ab initio (CCSD/6-311+G(d,p)) and DFT (B3LYP and M06 functionals at 6-311+G(d,p) and aug-cc-pVDZ basis set) calculations. The conformational and vibrational studies of 3-aminopropionitrile molecule were presented here are in very good interpretation of the calculated data compared with very poor interpretation in previous studies. The results showed that the gauche 2 conformer is more stable by 0.19 kcal/mol than gauche 1, outlined as enthalpy change ΔH between the conformers, at CCSD/6-311+G(d,p). Additionally, the population analysis shows that the gauche conformers are more prevalent than the trans conformers in the gas phase, present at 72.8%, with gauche 2 being the dominating gauche conformer at 40.1%. These results are in good agreement with earlier experimental and theoretical conclusions. All minima conformers' thermodynamic characteristics have also been studied. The relevant bond lengths, bond angles, and dihedral angles were calculated at a different level of theory for all possible conformers. The geometrical outcomes of the conformers agree very well with the previous experimental results. Electrostatic potential surface (ESP) has been used to interpret the structure-activity relationship. The atomic charges are examined, together with the energy difference between HOMO (Highest Occupied Molecular Orbital) and LUMO (Lowest Unoccupied Molecular Orbital). Additionally, the HOMO-LUMO energy gap and other relevant molecular properties are computed. The most stable conformers' stabilization energy has been determined by the Natural Bond Orbital (NBO) analysis. [ABSTRACT FROM AUTHOR]

Bimetallic nanoclusters have attracted great interest due to their ability to enhance the catalytic properties of nanoclusters through synergetic effects that emerge from the combination of the metal nanocluster with different transition metal (TM) species. However, their indefinite composition and broad distribution hinder the insightful understanding of the interaction between these invasive metals in bimetallic doped nanoalloys. In this study, we report a density functional theory calculation with the PBEsol exchange-correlation functional for 16-atom TiN−1TM (TM = Ni, Ir, Pd) nanoalloys, which provides new insights into the synergetic effect of these invasive metals. The probe into the effect of these metal impurities revealed that the replacement of a Ti atom with Ni, Ir and Pd enhances the relative stability of the nanoalloys, and the maximum stability for a lower bimetallic composition is reached for Ti4Ir, Ti5Pd and Ti7Ni. The most stable nanoalloy is reached for the Ti12Ir cluster in comparison with the Ti12Pd and Ti12Ni clusters and pure Ti13 monoatomic nanocluster. This stability trend is as revealed well by both the binding energy and the dissociation energy. The average HOMO-LUMO gap for the bigger clusters revealed that the valence electrons in the HOMO can absorb lower energy, which is indicatory of a higher reactivity and lower stability. The quantum confinement is higher for the smaller clusters, which illustrates a higher stability and lower reactivity for those systems.

Bimetallic nanoclusters have attracted great interest due to their ability to enhance the catalytic properties of nanoclusters through synergetic effects that emerge from the combination of the metal nanocluster with different transition metal (TM) species. However, their indefinite composition and broad distribution hinder the insightful understanding of the interaction between these invasive metals in bimetallic doped nanoalloys. In this study, we report a density functional theory calculation with the PBEsol exchange-correlation functional for 16-atom TiN−1TM (TM = Ni, Ir, Pd) nanoalloys, which provides new insights into the synergetic effect of these invasive metals. The probe into the effect of these metal impurities revealed that the replacement of a Ti atom with Ni, Ir and Pd enhances the relative stability of the nanoalloys, and the maximum stability for a lower bimetallic composition is reached for Ti4Ir, Ti5Pd and Ti7Ni. The most stable nanoalloy is reached for the Ti12Ir cluster in comparison with the Ti12Pd and Ti12Ni clusters and pure Ti13 monoatomic nanocluster. This stability trend is as revealed well by both the binding energy and the dissociation energy. The average HOMO-LUMO gap for the bigger clusters revealed that the valence electrons in the HOMO can absorb lower energy, which is indicatory of a higher reactivity and lower stability. The quantum confinement is higher for the smaller clusters, which illustrates a higher stability and lower reactivity for those systems. [ABSTRACT FROM AUTHOR]

The Mabuchi constant is a holomorphic invariant of Fano manifolds, which obstructs the existence of Mabuchi's generalized Kähler-Einstein metrics and relative Ding semistability. In this study, we give a formula for the Mabuchi constant of produtcs of Fano manifolds. As an application, we present examples of Fano manifolds which admit Calabi's extremal Kähler metrics in every Kähler class, but are relatively Ding unstable. [ABSTRACT FROM AUTHOR]

The rare earth element doped germanium cluster represents a fundamental nanomaterial and exhibits potential in next‐generation industrial electronic nanodevices and applied semiconductors. Herein, the cerium‐doped germanium anionic nanocluster CeGen− (n = 5–17) has been comprehensively investigated by the double hybrid density functional theory of mPW2PLYP associated with the unbiased global searching technique of artificial bee colony algorithm. The cluster's growth pattern undergoes three stages: n = 5–9 with the replaced structure, n = 10–15 with the linked structure, and n ≥ 16 forming a Ce‐encapsulated in Ge inner cage motif. The clusters' PES, IR, and Raman spectra were simulated, and their HOMO‐LUMO gap, magnetism, charge transfer, and relative stability were predicted. These theoretical values can serve as a reference for future experiments to some extent. Moreover, the special D2d symmetry cage geometry of CeGe16− leads to a higher stability and preferred energy gap, making it an ideal candidate for further studies on its aromaticity, UV–vis spectra, and chemical bonding characteristics. In summary, CeGe16− has excellent optical activity that can be potentially employed as a building block in the development of optoelectronic functional materials. [ABSTRACT FROM AUTHOR]

The mechanical systems were modeled using various combinations of mass-damper-spring elements to analyze the system dynamics and improve the system stability. Due to the marginal stability property of the mass-damper rectilinear system, a proper control law is required to control the mass position accurately, improve the relative stability, and enhance the dynamical response. In this paper, a mathematical model of the electromechanical system was first derived and analyzed. Next, a digital PID controller was developed based on the root locus technique, and a systematic design procedure is presented in detail. The proposed digital control system was simulated in MATLAB and compared with other control schemes to check their tracking performance and transient response characteristics. In addition, the digital PID control algorithm of the mass-damper rectilinear system was implemented via dSPACE platform to investigate the real-time control system performance and validate the control design methodology. It has been shown that the digital PID controller yields zero percentage overshoot, fast transient response, adequate stability margins, and zero steady-state error.

The rare earth dope d nano-cluster can be a building block for the next-generation photo-electrical industry, so the imminent discovery of novel, suitable nano-functional material is urgent. Praseodymium element as a wonderful dopant, bestow a novel photoelectrochemical properties for nanomaterials especially for semiconductor, derived from its unfulfilled 4f electrons configuration and active electronic transitions between 4f to 4f and 4f to 5d. In view of this, the neutral and anionic clusters of PrSin0/- with a medium size of n = 10–20 are comprehensively investigated by the quantum chemistry method of mPW2PLYP associated with the global searching potential energy surface techniques. The geometry evolution in medium size for PrSin can be attributed to three stages of replaced (n = 10–12), linked (n = 13–19), and cage (n = 20) structure. For PrSin-, two evolution phases are obviously observed by linked (n = 10–19) and cage (n = 20) structure. The PES spectra of the anionic most stable cluster and several degeneracy structures are simulated to identify the ground state structure. Each cluster of AEA, charge transfer, and VDE values are all calculated. Combined with binding energy, HOMO-LUMO gap, molecular orbital analysis, and a series of optical properties estimated, including simulated UV–vis, IR, and Raman spectra, excitation behavior shows PrSi20- has not only prominent stability but also has a proper range of lighting absorption, higher electron-hole recombination, possible as a functional material for optoelectronic devices.

The growth law, electronic properties and spectra of Fenλ (n = 2–18; λ = 0, ±1) clusters have been examined by density functional theory (DFT) and an unbiased structure prediction method. Extensive geometry optimizations have been executed and show that the global minimum structures of Fenλ clusters have a distinct growth law when n is 8–18. For n = 8–13 and 14–18, the iron atoms grow around a decahedral and icosahedral iron cluster core, respectively. Based on the present ground states, the calculated electronic parameters are in line with the experimental values. The thermal stability of charged iron cluster is higher than that of neutral iron cluster. The octahedral and icosahedral clusters are more stable than their neighbors. The former has low chemical activity and may be a superatom. The magnetic moment of Fe atom weakens in the cluster. The UV spectra, photoelectron spectra (PES) and infrared and Raman spectra of the Fenλ clusters have been predicted and the global minimum structures of the Fen− clusters are determined by comparing the theoretical PES with the experimental results. [ABSTRACT FROM AUTHOR]

In this paper, we prove that if a Gorenstein toric Fano variety (X , − K X) is asymptotically Chow semistable, then it is Ding polystable with respect to toric test configurations (Theorem 3). This extends the known result obtained by others (Theorem 2) to the case where X admits Gorenstein singularity. We also show the additivity of the Mabuchi constant for the product toric Fano varieties in Proposition 2 based on the author's recent work (Ono, Sano and Yotsutani in arxiv:2305.05924). Applying this formula to certain toric Fano varieties, we construct infinitely many examples that clarify the difference between relative K-stability and relative Ding stability in a systematic way (Proposition 1). Finally, we verify the relative Chow stability for Gorenstein toric del Pezzo surfaces using the combinatorial criterion developed in (Yotsutani and Zhou in Tohoku Math. J.71 (2019), 495–524.) and specifying the symmetry of the associated polytopes as well. [ABSTRACT FROM AUTHOR]

Summary: This paper presents an efficient optimization strategy based on the Stoyan and Yaskov algorithm to maximize the tube density of randomly distributed mixed carbon nanotube bundles (RMCBs) for configuring optimum performance of on‐chip interconnects. Optimizing tube density has proposed eight different RMCB (RMCB1–RMCB8) structures of a varying number of carbon nanotubes (CNTs), where RMCB1 has the maximum CNTs. Moreover, the ABCD technique adequately analyzes the temperature‐dependent frequency and stability characteristics of a three‐line RMCB interconnect placed on smooth and rough substrates (SiC, BN, and SiO2). The smooth substrate material has the best 3‐dB bandwidth compared with rough SiC substrate, followed by BN and SiO2 for all RMCB structures, and among all structures, the RMCB8 has the best 3‐dB bandwidth. The relative stability of RMCB1 is improved by 134.2% and 22.7% w.r.t. RMCB8 placed on a smooth and rough SiC substrate, respectively. Whereas bandwidth of the RMCB1 is reduced by 26% and 88.5% w.r.t. RMCB8 placed on a smooth and rough substrate, respectively. Hence, there is a tradeoff between the bandwidth and the relative stability as the number of CNT increases. Therefore, RMCB3 placed on a smooth substrate and RMCB4 placed on a rough SiC substrate are considered the best‐optimized RMCB interconnects to maintain a balance between the two. [ABSTRACT FROM AUTHOR]

Boolean models are a well-established framework to model developmental gene regulatory networks (DGRNs) for acquisition of cellular identities. During the reconstruction of Boolean DGRNs, even if the network structure is given, there is generally a large number of combinations of Boolean functions that will reproduce the different cell fates (biological attractors). Here we leverage the developmental landscape to enable model selection on such ensembles using the relative stability of the attractors. First we show that previously proposed measures of relative stability are strongly correlated and we stress the usefulness of the one that captures best the cell state transitions via the mean first passage time (MFPT) as it also allows the construction of a cellular lineage tree. A property of great computational importance is the insensitivity of the different stability measures to changes in noise intensities. That allows us to use stochastic approaches to estimate the MFPT and thereby scale up the computations to large networks. Given this methodology, we revisit different Boolean models of Arabidopsis thaliana root development, showing that a most recent one does not respect the biologically expected hierarchy of cell states based on relative stabilities. We therefore developed an iterative greedy algorithm that searches for models which satisfy the expected hierarchy of cell states and found that its application to the root development model yields many models that meet this expectation. Our methodology thus provides new tools that can enable reconstruction of more realistic and accurate Boolean models of DGRNs. [ABSTRACT FROM AUTHOR]

Pyrazinamide may exist in at least four known polymorphic forms, which were obtained experimentally. One of these polymorphs, (α), shows outstanding mechanical properties, demonstrating a significant anisotropic plasticity in a three-point bending test, while the δ form was brittle. Despite a δ → α transition as well as β and γ behavior being experimentally studied, the relative stability of pyrazinamide polymorphs remains unclear and even controversial. In this work we provide a pure computational study of the thermodynamic relationships between all four polymorphs as a function of temperature using periodic DFT calculations. It was shown that the β but not the δ form is the most stable at low temperatures. Moreover, the relative stability of the δ form in comparison to α is questioned, showing that the "brittle to bending" δ → α transition was kinetically hindered in the experiments. We show that α and γ polymorphs were stabilized at higher temperatures due to an entropy term. Finally, the calculated stability of the bending α form of pyrazinamide at room temperature was in perfect agreement with previous experiments, which showed a transformation of all other forms to α during six month storage or grinding. [ABSTRACT FROM AUTHOR]

To gain insight into the effect of Si/C arrangement on the molecular framework of strained polyhedral compounds, dodecahedrane analogues containing equal numbers of carbon and silicon (Si/C equally mixed dodecahedrane analogues) were investigated using the ab initio molecular orbital method. There are 1648 isomers for which the Si/C arrangement on the molecular framework is different. Based on the geometry optimization of all the isomers as well as the carbon and silicon analogues, the characteristics of the structure, relative energy, and strain energy of the Si/C equally mixed compounds are presented. Then, important factors controlling the relative energy, such as strain energy, are proposed through regression analysis. Also discussed is the correlation between the relative energy and the indices of Si/C dispersion, such as the number of skeletal C–Si single bonds and condensed five-membered rings constituting the polyhedral structure. [ABSTRACT FROM AUTHOR]

The contemporary scientific community is very familiar with implicit block techniques for solving initial value problems in ordinary differential equations. This is due to the fact that these techniques are cost effective, consistent and stable, and they typically converge quickly when applied to solve particularly stiff models. These aspects of block techniques are the key motivations for the one-step optimized block technique with two off-grid points that was developed in the current research project. Based on collocation points, a family of block techniques can be devised, and it is shown that an optimal member of the family can be picked up from the leading term of the local truncation error. The theoretical analysis is taken into consideration, and some of the concepts that are looked at are the order of convergence, consistency, zero-stability, linear stability, order stars, and the local truncation error. Through the use of numerical simulations of models from epidemiology, it was demonstrated that the technique is superior to the numerous existing methodologies that share comparable characteristics. For numerical simulation, a number of models from different areas of medical science were taken into account. These include the SIR model from epidemiology, the ventricular arrhythmia model from the pharmacy, the biomass transfer model from plants, and a few more. [ABSTRACT FROM AUTHOR]

In this paper, we study the class of relatively D -stable matrices and provide sufficient conditions for relative D -stability. We generalize the well-known Hadamard inequality, to provide upper bounds for the determinants of relatively D -stable and relatively additive D -stable matrices. For some classes of D -stable matrices, we estimate the sector gap between matrix spectra and the imaginary axis. We apply the developed technique to obtain upper bounds for determinants of some classes of D -stable matrices, e.g. diagonally stable, diagonally dominant and matrices with Q 2 -scalings. [ABSTRACT FROM AUTHOR]

The intermolecular interactions of active pharmaceutical ingredients (APIs) are the driving forces of API molecular activity and stability, in vivo receptor binding, environmental transport, and persistence. In manufacturing, API complexation with another molecule to create stable crystalline structures is pursued, but the formation of more energetically stable complexes can lead to undesired consequences. Density functional theory (DFT) was used to describe the role played by hydrogen bonding in the formation of paracetamol and oxalic acid (PCA-OXA) complexes. PCA-OXA hydrogen bonding sites were investigated to determine strength and overall contribution/competition during the initial stages of the nucleation process. Structural and energetic changes were evaluated for 1:1 PCA-OXA, PCA-Water, and OXA-Water complexes both in vacuum and in water environments via explicit and implicit solvation. Results show significant shortening of the hydrogen bonds within the PCA-OXA complex with large changes in energy in the PCA-OXA complexation mechanism. Two out of the four complexation sites play the largest roles in the initial steps of the nucleation process. In an aqueous environment, little to no energetic competition for PCA hydrogen bonds formation with other molecules is observed. Post Hartree–Fock methods (MP2 and CCSD) were used to calibrate and verify the DFT results. [ABSTRACT FROM AUTHOR]

The paper presents a new approach to the design of the classical PD controller for the plant in the closed loop control system. Proposed controller has two unknown adjustable parameters which are designed by the algebraic method in the two dimensional parameter space, by using the newly discovered characteristic polynomial of the row nondegenerate full transfer function matrix. The system relative stability, in regard to the chosen damping coefficient is achieved. The optimality criterion is the minimal value of the performance index and sum of squared error is taken as an objective function. The output error used in the performance index is influenced by all actions on the system at the same time: by nonzero initial conditions and by nonzero inputs. In the classical approach the output error is influenced only by nonzero inputs. Experimental results confirm that by taking into account nonzero initial conditions, an optimal solution is obtained, which is not the case with the classical method where optimization is performed at zero initial conditions.

The sub-threshold regime is suited for applications requiring ultra-low power consumption with low to medium frequency (tens to hundreds of MHz) of operation. Therefore, this paper presents electrical modeling and comprehensive analysis of copper-carbon nanotube (Cu-CNT) composite interconnects for sub-threshold circuit design. At lower operating frequencies, the effective complex conductivity of Cu-CNT composites in the nanoscale is formulated by developing an analytical model. Based on the proposed equivalent single conductor model, the frequency-dependent resistance and inductance of composite interconnects are computed. Finally, the sub-threshold crosstalk effect, transfer gain, and Nyquist stability of coupled Cu-CNT composite interconnect are analyzed using ABCD matrix approach.

A challenge in dealing with gender dysphoria in children is the mixture of stable and temporary fluctuations in the feelings of gender dysphoria during development. This study examines the absolute and relative stability and the patterns of change of the feelings of gender dysphoria using data from a six-year longitudinal survey across three cohorts. The participants consisted of 2,031 people (999 boys and 1,032 girls) from fourth to ninth grades who completed the feelings of gender dysphoria scale. As a consequence of examining the changes in mean values by grade as absolute stability, the scores of boys slightly decreased from fourth to ninth grade; however, almost no significant change was found for girls. Latent profile analysis revealed 11 patterns including 22.6% of students who increased the score only within 1-2 years. The correlation between each grade as relative stability resulted in a positive correlation between each grade for boys and girls. In addition, the correlation coefficient increased as the grade increased, indicating that relative stability increased. The correlation coefficient was higher for girls than boys. [ABSTRACT FROM AUTHOR]

In this paper, we prove that if a Gorenstein toric Fano variety (X,−KX) is asymptotically Chow semistable, then it is Ding polystable with respect to toric test configurations (Theorem 3). This extends the known result obtained by others (Theorem 2) to the case where X admits Gorenstein singularity. We also show the additivity of the Mabuchi constant for the product toric Fano varieties in Proposition 2 based on the author’s recent work (Ono, Sano and Yotsutani in arxiv:2305.05924). Applying this formula to certain toric Fano varieties, we construct infinitely many examples that clarify the difference between relative K-stability and relative Ding stability in a systematic way (Proposition 1). Finally, we verify the relative Chow stability for Gorenstein toric del Pezzo surfaces using the combinatorial criterion developed in (Yotsutani and Zhou in Tohoku Math. J.71 (2019), 495–524.) and specifying the symmetry of the associated polytopes as well.

The investigation of molecular crystals at high pressure is a sought-after trend in crystallography, pharmaceutics, solid state chemistry, and materials sciences. The di-p-tolyl disulfide (CH3−C6H4−S−)2 system is a bright example of high-pressure polymorphism. It contains "conventional" solid–solid transition and a "hidden" form which may be obtained only from solution at elevated pressure. In this work, we apply force field and periodic DFT computational techniques to evaluate the thermodynamic stability of three di-p-tolyl disulfide polymorphs as a function of pressure. Theoretical pressures and driving forces for polymorphic transitions are defined, showing that the compressibility of the γ phase is the key point for higher stability at elevated pressures. Transition state energies are also estimated for α → β and α → γ transitions from thermodynamic characteristics of crystal structures, not exceeding 5 kJ/mol. The β → γ transition does not occur experimentally in the 0.0–2.8 GPa pressure range because transition state energy is greater than 18 kJ/mol. Relations between free Gibbs energy (in assumption of enthalpy) of phases α, β, and γ, as a function of pressure, are suggested to supplement and refine experimental data. A brief discussion of the computational techniques used for high-pressure phase transitions is provided. [ABSTRACT FROM AUTHOR]

[Display omitted] • Three ZrO 2 polymorphs with TiO 2 origins—mp-1840, mp-9173, and mp-754769, are revealed for the first time. • DFT calculations at 0 K and zero pressure reveal stability trends by analyzing total energy relative to volume. • Reported spatial dependence moduli for ZrO 2 polymorphs. • Distinct IR and Raman fingerprint regions identified for stable ZrO 2 polymorphs. • ZrO 2 polymorphs have bandgaps of 4.1–5.5 eV, ideal for UV photon absorption and photovoltaic use. The importance of advanced materials like zirconium dioxide (ZrO 2) in diverse medical, industrial, and technological contexts is underscored by contemporary technology. ZrO 2 ′s unique combination of properties renders it indispensable for a broad spectrum of applications, suggesting its enduring importance. This study presents the very first investigation into the physical properties, structural stability, and ground-state characteristics of sixteen distinct ZrO 2 polymorphs through the application of density functional theory (DFT). Motivated by the potential of ZrO 2 polymorphs to substitute for SiO 2 , we conducted calculations to ascertain their dielectric properties. A comprehensive analysis was conducted on all structural features, and their stability was assessed. ZrO 2 polymorphs exhibit a wide bandgap with the type of bandgap also examined. Calculated zone-center phonon frequencies demonstrate the dynamical stability of ZrO 2 , with existing polymorphs showing strong agreement with experimental frequencies, particularly within the monoclinic polymorph. Raman and infrared (IR) spectra of ZrO 2 polymorphs were simulated using density functional perturbation theory. ZrO 2 demonstrates notable mechanical stability, as evidenced by calculated hardness (moduli), ductility, improved ductility, and higher elasticity. Calculated optical properties, including the dielectric constant and refractive index of ZrO 2 polymorphs, play a pivotal role in optimizing their performance in various applications such as optoelectronic devices and antireflective materials. [ABSTRACT FROM AUTHOR]

Pyrazinamide may exist in at least four known polymorphic forms, which were obtained experimentally. One of these polymorphs, (α), shows outstanding mechanical properties, demonstrating a significant anisotropic plasticity in a three-point bending test, while the δ form was brittle. Despite a δ → α transition as well as β and γ behavior being experimentally studied, the relative stability of pyrazinamide polymorphs remains unclear and even controversial. In this work we provide a pure computational study of the thermodynamic relationships between all four polymorphs as a function of temperature using periodic DFT calculations. It was shown that the β but not the δ form is the most stable at low temperatures. Moreover, the relative stability of the δ form in comparison to α is questioned, showing that the “brittle to bending” δ → α transition was kinetically hindered in the experiments. We show that α and γ polymorphs were stabilized at higher temperatures due to an entropy term. Finally, the calculated stability of the bending α form of pyrazinamide at room temperature was in perfect agreement with previous experiments, which showed a transformation of all other forms to α during six month storage or grinding.

We generalize the concepts of D-stability and additive D-stability of matrices. For this, we consider a family of unbounded regions defined in terms of Linear Matrix Inequalities (so-called LMI regions). We study the problem when the localization of a matrix spectrum in an unbounded LMI region is preserved under specific multiplicative and additive perturbations of the initial matrix. The most well-known particular cases of unbounded LMI regions (namely, conic sectors and shifted halfplanes) are considered. A new D-stability criterion as well as sufficient conditions for generalized D-stability are analyzed. Several applications of the developed theory to dynamical systems are shown. [ABSTRACT FROM AUTHOR]

Purpose: The objective of this study is to evaluate the effect of absolute stability (AS) versus relative stability (RS) performed through a minimally invasive plate osteosynthesis (MIPO) in AO/OTA 12A1 and 12A2 fractures on healing and the time to radiographic union. Methods: This was a retrospective cohort study of all patients treated with plate fixation for AO/OTA type 12A1–A2 fractures at a single institution. Patients were grouped according to the type of stability used in their surgery. Time until radiographic union was estimated using the Kaplan–Meier method, which was compared by long-rank test between both types of surgical techniques. Results: A total of 70 patients were included in this study with 35 patients in each group. The median follow-up was 9 (IQR 6–14) months. The median time to radiographic union was significantly lower in the AS group than in the RS group: 12 (interquartile range (IQR) 10–14) weeks versus 18 (IQR 16–19) weeks, respectively (p < 0.001). Non-union was seen in two cases (7%) in the relative stability group. Three patients in the RS group developed a post-operative radial nerve palsy. Conclusion: The main finding of this study is that the median time to radiographic union was significantly shorter in the patients treated with AS compared to those with a RS technique. These findings support the recommendations of the AO foundation in that simple metaphyseal fractures (type A) that require surgical treatment should be treated with an AS construct. RS techniques should be reserved to multifragmentary fractures where fragment preservation of blood supply is paramount. [ABSTRACT FROM AUTHOR]

Studies on Cu-doped germanium clusters in the neutral and mono-anion states CuGen−/0 (n = 4–13) are carried out employing a double-hybrid density functional mPW2PLYP scheme. The global minimal structure, spectral property, HOMO–LUMO gap, and stability of CuGen−/0 (n = 4–13) were confirmed. The results showed that the global minimal structures of the anionic clusters are Cu-substituted for a Ge in the ground state of anionic Gen+1− with n ≤ 8, and Cu atom is encapsulated into germanium cages starting from n = 9. For neutral, it is also Cu-encapsulated into cage-like Ge framework with n ≥ 9. The spectra information including adiabatic electron affinity, vertical detachment energy and simulated photoelectron spectroscopy were presented. The HOMO–LUMO gap, atomization energy, and second energy difference for CuGen−/0 (n = 4–13) clusters along with NICS of CuGe12− were evaluated to examine the thermodynamic and chemical stability. The results revealed that anionic cluster CuGe12− with a high-symmetry endohedral Ih configuration possessed a perfect thermodynamic stability and chemical reactivity, making it possible as appropriate building block for new multi-functional semiconductor materials. [ABSTRACT FROM AUTHOR]

To gain insight into the effect of Si/C arrangement on the molecular framework of strained polyhedral compounds, dodecahedrane analogues containing equal numbers of carbon and silicon (Si/C equally mixed dodecahedrane analogues) were investigated using the ab initio molecular orbital method. There are 1648 isomers for which the Si/C arrangement on the molecular framework is different. Based on the geometry optimization of all the isomers as well as the carbon and silicon analogues, the characteristics of the structure, relative energy, and strain energy of the Si/C equally mixed compounds are presented. Then, important factors controlling the relative energy, such as strain energy, are proposed through regression analysis. Also discussed is the correlation between the relative energy and the indices of Si/C dispersion, such as the number of skeletal C–Si single bonds and condensed five-membered rings constituting the polyhedral structure.

The contemporary scientific community is very familiar with implicit block techniques for solving initial value problems in ordinary differential equations. This is due to the fact that these techniques are cost effective, consistent and stable, and they typically converge quickly when applied to solve particularly stiff models. These aspects of block techniques are the key motivations for the one-step optimized block technique with two off-grid points that was developed in the current research project. Based on collocation points, a family of block techniques can be devised, and it is shown that an optimal member of the family can be picked up from the leading term of the local truncation error. The theoretical analysis is taken into consideration, and some of the concepts that are looked at are the order of convergence, consistency, zero-stability, linear stability, order stars, and the local truncation error. Through the use of numerical simulations of models from epidemiology, it was demonstrated that the technique is superior to the numerous existing methodologies that share comparable characteristics. For numerical simulation, a number of models from different areas of medical science were taken into account. These include the SIR model from epidemiology, the ventricular arrhythmia model from the pharmacy, the biomass transfer model from plants, and a few more.

Objectives: Low self control has been the principal focus of population heterogeneity perspectives in terms of capturing an individual's antisocial and criminal propensity (ACP). However, conceptual descriptions of the stability of psychopathy, combined with evidence that this construct predicts chronic and violent offending, implies that it may be a more accurate indicator of ACP. The current study evaluated this assertion by examining the extent to which features of psychopathy were defined by relative change. Methods: Using data on adolescent males from the Pathways to Desistance Study (n = 1170), the current study introduced P(∆i) as a new analytic strategy suitable for examining whether a person's within-individual change on a given construct resulted in between-person differences. Results: In applying P(∆i) to test scores on the Youth Psychopathic Traits Inventory (YPI), little support was found for features of psychopathy as a stable indicator of ACP between adolescence and adulthood. Contrary to expectations from a population heterogeneity perspective, higher test scores on the YPI were associated with an increased likelihood of experiencing relative decreases in features of psychopathy. Interpersonal features of psychopathy were most likely to change. Conclusions: Assertions about adolescents with features of psychopathy as posing a life-long risk for reoffending may require revisitation. Replication is needed using expert rating tools as opposed to tools that only rely on self-reported information. [ABSTRACT FROM AUTHOR]

In a recent nano and deep-submicron regime, the electromagnetic interference primarily plays an important role in determining the overall interconnect performance of an integrated circuit (IC). For instance, it can cause lower reliability, and stability in silicon technology. In order to mitigate these challenges, this work introduces a new technique of active shielding by introducing a jacketed side- (SC) and top-contact (TC) multi-layered graphene nanoribbon (MLGNR) interconnect to demonstrate the relative stability. Depending on the physical configuration, an accurate Pi-type electrical network is proposed for the shielded TC-and SC-MLGNR at 32 nm technology. Using the equivalent circuit model, a fifth-order transfer function is employed to demonstrate the relative stability of SC- and TC-MLGNR at global interconnect lengths. [ABSTRACT FROM AUTHOR]

Understanding binding site preferences in biological systems as well as affinities to binding partners is a crucial aspect in metallodrug development. We here present a mass spectrometry‐based method to compare relative stabilities of metal‐peptide adducts in the gas phase. Angiotensin 1 and substance P were used as model peptides. Incubation with isostructural N‐heterocyclic carbene (NHC) complexes of RuII, OsII, RhIII, and IrIII led to the formation of various adducts, which were subsequently studied by energy‐resolved fragmentation experiments. The gas‐phase stability of the metal‐peptide bonds depended on the metal and the binding partner. Of the four complexes used, the OsII derivative bound strongest to Met, while RuII formed the most stable coordination bond with His. RhIII was identified as the weakest peptide binder and IrIII formed peptide adducts with intermediate stability. Probing these intrinsic gas‐phase properties can help in the interpretation of biological activities and the design of site‐specific protein binding metal complexes. [ABSTRACT FROM AUTHOR]

Dynamic systems operate under the simultaneous influence of both the initial conditions and the input vector. There is neither physical nor mathematical justification for ignoring the initial conditions, e.g., in the control optimisation. This paper gives a response to the following question: Is a set of controller parameters which is optimal for the operation of a control system under zero initial conditions also optimal for its operation under non-zero initial conditions? The paper presents a new approach to the design of a classical proportional-difference-sum (PDS) controller for a plant in a closed loop control system. The system relative stability with respect to a desired damping coefficient is accomplished. The minimal value of the performance index in the form of the sum of squared errors is the optimality criterion. Unlike the classical approach, the output error used in the performance index is influenced by all actions performed on the system at the same time. [ABSTRACT FROM AUTHOR]

Galveston Bay is a subtropical estuary on the upper Texas coast along the northwestern region of the Gulf of Mexico (USA). This study presents results of a meta-analysis on fisheries independent abundance and environmental data collected from 1993 to 2016 (3469 sampling events). In total, 404,160 individual fish were collected using bag seines comprising 122 species from 91 genera, 53 families and 22 orders. Diversity measures reveal the number of individuals, species richness and the Shannon diversity index exhibit a seasonal cycle (decrease in winter, increase in summer). Fish populations also exhibited spatial variability which was largely attributed to the varying stages of their life cycles. Community metrics varied temporally and were not adversely influenced by periods of drought, flood, or other extreme events. Galveston Bay appears to be providing a sound ecological environment, and not yet exhibiting climate change influences on the fishery, as has been reported for other estuaries. • Spatial and temporal variability of estuarine fish over 24 years in Galveston Bay. • 404,160 individuals and environmental data (PSU, °C, mg/L) over 3469 sampling events. • Temperature and salinity alter the diversity and richness of fish communities. • Subtropical Galveston Bay fish less studied but appear to be buffering pressures. • Community metrics not adversely influenced by droughts, flood or other extreme events. [ABSTRACT FROM AUTHOR]

Abstract Background Plate fixation is one of the standard surgical treatments for distal femoral fractures. There are few reports on the relationship between the screw position and bone union when fixing by the bridging plate (relative stability) method. Methods This retrospective study included 71 distal femoral fractures of 70 patients who were treated with the locking compression plate for distal femur (DePuy Synthes Co., Ltd, New Brunswick, CA, USA). The following measurements were evaluated and analyzed: (1) bone union rate, (2) bridge span length (distance between screws across the fracture), (3) plate span ratio (plate length/bone fracture length), (4) number of empty holes (number of screw holes not inserted around the fracture), and (5) medial fracture distance (bone fracture distance on the medial side of the distal femur). Patient demographics (age), comorbidities (smoking, diabetes, chronic steroid use, dialysis), and injury characteristics (AO type, open fracture, infection) were obtained for all participants. Univariate analysis was performed on them. Results Of 71 fractures, 26 fractures were simple fractures, 45 fractures were comminuted fractures, and 7 fractures resulted in non-union. Non-union rate was significantly higher in comminuted fractures with bone medial fracture distance exceeding 5 mm. Non-union was founded in simple fractures with bone medial fracture distance exceeding 2 mm, but not significant (p = 0.06). In cases with simple fractures, one non-union case had one empty hole and one non-union case had four empty holes, whereas in cases with comminuted fractures, five non-union cases had two more empty holes. Conclusions We concluded that bone fragment distance between fracture fragments is more important than bridge span length of the fracture site and the number of empty holes. Smoking and medial fracture distance are prognostic risk factors of nonunion in distal femoral fractures treated with LCP as bridging plate.

The investigation of molecular crystals at high pressure is a sought-after trend in crystallography, pharmaceutics, solid state chemistry, and materials sciences. The di-p-tolyl disulfide (CH3−C6H4−S−)2 system is a bright example of high-pressure polymorphism. It contains “conventional” solid–solid transition and a “hidden” form which may be obtained only from solution at elevated pressure. In this work, we apply force field and periodic DFT computational techniques to evaluate the thermodynamic stability of three di-p-tolyl disulfide polymorphs as a function of pressure. Theoretical pressures and driving forces for polymorphic transitions are defined, showing that the compressibility of the γ phase is the key point for higher stability at elevated pressures. Transition state energies are also estimated for α → β and α → γ transitions from thermodynamic characteristics of crystal structures, not exceeding 5 kJ/mol. The β → γ transition does not occur experimentally in the 0.0–2.8 GPa pressure range because transition state energy is greater than 18 kJ/mol. Relations between free Gibbs energy (in assumption of enthalpy) of phases α, β, and γ, as a function of pressure, are suggested to supplement and refine experimental data. A brief discussion of the computational techniques used for high-pressure phase transitions is provided.

Proportional-integral-derivative (PID) control is commonly used in industrial automatic control systems. However, it is not straightforward to determine control gains in a PID controller for satisfactory closed-loop performance. Many research works have been devoted to the auto-tuning of PID control gains. In contrast to previous studies, this paper develops an auto-tuning rule for PID controllers to simultaneously satisfy specifications of both steady-state error and relative stability, in which stability is specified in terms of phase margin. To illustrate the proposed auto-tuning rule, a focus servo of an optical disk drive is used, in which a voice coil motor drives a lens to focus a laser beam on a data layer of an optical disk. Experimental results show the effectiveness of the proposed PID auto-tuning process. [ABSTRACT FROM AUTHOR]

We prove that hβ(x) = β∫x0 yβ-1F¯(y)dy is regularly varying with index ∈ [0, β) if and only if Vβ(x) = ∫[0,x] yβdF(y) is regularly varying with the same index, where β > 0, F(x) is a distribution function of a nonnegative random variable, and F¯(x) = 1-F(x). This contains at ρ = 0, β= 1 a result of Rogozin [8] on relative stability, and at ρ = 0, β = 2 a new, equivalent characterization of the domain of attraction of the normal law. For ρ = 0 and β > 0 our result implies a recent conjecture by Seneta [9]. [ABSTRACT FROM AUTHOR]