Cell Dimensions Research Articles

Combined physical training protects the left ventricle from structural and functional damages in experimental pulmonary arterial hypertension

BackgroundUnder the adverse remodeling of the right ventricle and interventricular septum in pulmonary arterial hypertension (PAH) the left ventricle (LV) dynamics is impaired. Despite the benefits of combined aerobic and resistance physical trainings to individuals with PAH, its impact on the LV is not fully understood.ObjectiveTo test whether moderate-intensity combined physical training performed during the development of PAH induced by MCT in rats is beneficial to the LV’s structure and function.MethodsMale Wistar rats were divided into two groups: Sedentary Hypertensive Survival (SHS, n = 7); and Exercise Hypertensive Survival (EHS, n = 7) to test survival. To investigate the effects of combined physical training, another group of rats were divided into three groups: Sedentary Control (SC, n = 7); Sedentary Hypertensive (SH, n = 7); and Exercise Hypertensive (EH, n = 7). PAH was induced through an intraperitoneal injection of MCT (60 mg/kg). Echocardiographic evaluations were conducted on the 22nd day after MCT administration. Animals in the EHS and EH groups participated in a combined physical training program, alternating aerobic (treadmill running: 50 min, 60% maximum running speed) and resistance (ladder climbing: 15 climbs with 1 min interval, 60% maximum carrying load) exercises, one session/day, 5 days/week for approximately 4 weeks.ResultsThe physical training increased survival and tolerance to aerobic (i.e., maximum running speed) and resistance (i.e., maximum carrying load) exertions and prevented reductions in ejection fraction and fractional shortening. In addition, the physical training mitigated oxidative stress (i.e., CAT, SOD and MDA) and inhibited adverse LV remodeling (i.e., Collagen, extracellular matrix, and cell dimensions). Moreover, the physical training preserved the amplitude and velocity of contraction and hindered the reductions in the amplitude and velocity of the intracellular Ca2+ transient in LV single myocytes.ConclusionModerate-intensity combined physical training performed during the development of MCT-induced PAH in rats protects their LV from damages to its structure and function and hence increases their tolerance to physical exertion and prolongs their survival.

Performance optimization for a scintillating glass electromagnetic calorimeter at the EIC

The successful realization of the EIC scientific program requires the design and construction of high-performance particle detectors. Recent developments in the field of scientific computing and increased availability of high performance computing resources have made it possible to perform optimization of multi-parameter designs, even when the latter require longer computational times (for example simulations of particle interactions with matter). Procedures involving machine-assisted techniques used to inform the design decision have seen a considerable growth in popularity among the EIC detector community. Having already been realized for tracking and RICH PID detectors, it has a potential application in calorimetry designs. A SciGlass barrel calorimeter originally designed for EIC Detector-1 has a semi-projective geometry that allows for non-trivial performance gains, but also poses special challenges in the way of effective exploration of the design space while satisfying the available space and the cell dimension constraints together with the full detector acceptance requirement. This talk will cover specific approaches taken to perform this detector design optimization.

Honeycomb Elastic Metasurfaces for Broadband Control of Flexural Waves

Elastic metasurfaces are artificial planar structures endowed with unique properties that natural materials do not possess. They exhibit significant potential in the realm of wave control. Despite the widespread attention garnered by metasurfaces due to their ultrathin profile, ease of design and fabrication, and enhanced physical characteristics, they still grapple with the challenge posed by their narrow operational bandwidth. In this study, a structurally compact, subwavelength-scale honeycomb metasurface is proposed for broadband manipulation of flexural waves. Through modulation of the unit cell dimensions, precise control over the phase is achieved, enabling a series of remarkable wavefront manipulations, including anomalous refraction, energy concentration, self-bending beam, and source illusion. Results indicate that compared to conventional localized resonance metasurfaces, the introduced approach offers advantages in terms of broad bandwidth, compactness, and high efficiency. This endeavor holds the potential to provide more comprehensive methods for vibration attenuation, noise reduction, and wave control.

Spectro-hierarchical homogenization scheme for elasto-dynamic problems in periodic Cauchy materials

A spectro-hierarchical algorithm is proposed to determine an approximate solution to the elasto-dynamic problem for periodic heterogeneous materials. Such a homogenization scheme is derived by employing tools from perturbation theory in finite dimension used in the context of the celebrated Theorem of Nekhoroshev. In particular, it is shown how a classical algorithm based on a suitable hierarchy of harmonics can be implemented for the problem at hand, leading to the explicit construction of functions approximating the solution of the original problem with an error that is superexponentially small in the cell dimension. According to this approach, the fully homogenized model turns out to be naturally related to the “integrable case” of perturbation theory. Furthermore, all the featured constants are estimated explicitly. More importantly, a fully detailed bound of the threshold for the cell dimension is presented to ensure the validity of the theory. An example of application of the described theory is given in the final section for the case of a layered material.

Effect of Reinforcement on Micro Structural and Compressive Deformation Behavior on Closed Cell AA7075 Aluminium Foam

Effect of Reinforcement on Micro Structural and Compressive Deformation Behavior on Closed Cell AA7075 Aluminium Foam

An ultrathin wideband linear-to-circular polarization conversion metasurface for X-band applications

A specialized ultrathin metasurface has been developed to transform a linearly polarized incident wave into a reflected wave with circular polarization across a wide range of frequencies. The unit cell consists of two modified L-shaped structures that convert the incident linearly polarized wave to a circularly polarized wave. The axial ratio bandwidth of the reflected wave ranges from 8.19 to 11.08 GHz, exhibiting a fractional bandwidth of 30%. The dimensions of the unit cell are 7 × 7 ×1.6mm3 (0.225λ×0.225λ×0.051λ) where λ represents the center frequency within the operational frequency band. The proposed design not only provides a wide bandwidth but also is ultrathin as the dimensions are much less than λ/12. Finally, the proposed metasurface is fabricated and tested. The results obtained are in significant concurrence with the simulated results. Hence, it can be used in various applications, including implementation in multi-beam antennas, beam-scanning antennas, wireless systems, weather monitoring, radar tracking, and navigation systems.

Wallace’s line structures seagrass microbiota and is a potential barrier to the dispersal of marine bacteria

BackgroundThe processes that shape microbial biogeography are not well understood, and concepts that apply to macroorganisms, like dispersal barriers, may not affect microorganisms in the same predictable ways. To better understand how known macro-scale biogeographic processes can be applied at micro-scales, we examined seagrass associated microbiota on either side of Wallace’s line to determine the influence of this cryptic dispersal boundary on the community structure of microorganisms. Communities were examined from twelve locations throughout Indonesia on either side of this theoretical line.ResultsWe found significant differences in microbial community structure on either side of this boundary (R2 = 0.09; P = 0.001), and identified seven microbial genera as differentially abundant on either side of the line, six of these were more abundant in the West, with the other more strongly associated with the East. Genera found to be differentially abundant had significantly smaller minimum cell dimensions (GLM: t923 = 59.50, P < 0.001) than the overall community.ConclusionDespite the assumed excellent dispersal ability of microbes, we were able to detect significant differences in community structure on either side of this cryptic biogeographic boundary. Samples from the two closest islands on opposite sides of the line, Bali and Komodo, were more different from each other than either was to its most distant island on the same side. We suggest that limited dispersal across this barrier coupled with habitat differences are primarily responsible for the patterns observed. The cryptic processes that drive macroorganism community divergence across this region may also play a role in the bigeographic patterns of microbiota.

Penta-band polarization insensitive ultra-thin metamaterial absorber suitable for flux shielding in WPT

This study introduces a novel multi-band, polarization-insensitive metamaterial absorber, designed by combining a dual-band and a triple-band resonator structures. Through the amalgamation of discrete absorption responses from these structures, the resulting design exhibits five absorption peaks at frequencies: 1.5 GHz (80%), 3.6 GHz (88%), 5.46 GHz (95%), 7.17 GHz (95%), and 9.17 GHz (95%). One of the standout features of the proposed design lies in its four-fold symmetry, endowing it with polarization insensitivity. This ensures robust performance regardless of the incident polarization, enhancing the versatility and applicability of the absorber in various scenarios. The design’s compact nature is noteworthy, with a unit cell dimension of only 0.125λ. This compactness not only contributes to space-efficient deployment but also underscores the efficiency of the metamaterial in achieving multiple absorption peaks within a limited spatial footprint. In addition to its compactness, the absorber is ultra-thin, with a dielectric thickness of merely 0.008λ. This characteristic is particularly advantageous for applications where a low-profile and lightweight solution is essential, such as in the development of inconspicuous communication devices or electromagnetic shielding.

A simulation-based performance evaluation of new generation dynamic shading devices with multi-objective optimization

Shading devices are the integrated components of building envelopes, which are designed to protect interiors from the excessive amount of direct and indirect solar radiation. Blocking the sunlight, these devices reduce the operational cost of cooling systems, which implies an inverse proportionality between the cooling energy consumption and desired thermal comfort. Therefore, in this study, a unique design for dynamic shading devices of an office building, located in the hot and humid climatic region, is proposed and presented from the early stages of the architectural design process. Above all, an innovative parametric model is created using the Grasshopper algorithmic modeling environment with the Honeybee and Ladybug plug-ins to overcome all difficulties of the manual design process. By employing the optimization plug-in of the Grasshopper software named Octopus, a performance evaluation based multi-objective optimization (MOO) method is introduced to find different cell dimensions of the devices for various orientations, south, east and west, of the office building. This research also investigates the potential of the proposed shading devices based on two major performance aspects, reducing the cooling load while increasing the thermal comfort of the office building, located at Bayrakli, Izmir, Turkey, latitude: 38° 27′ 44.00″ N and longitude: 27° 10′ 0.00″ E. The lowest cooling energy consumption is estimated as 8.35 kWh for 22nd of July 12:00 a.m. for the west orientation with the dimension of 100 × 100 cm, among other cell dimensions, which are 50 × 200 cm and 200 × 50 cm. The novelty lies behind the optimization of the conflicting performance features and the design of the new generation dynamic shading devices which would shed light on new shading device era.

A wideband multi-bit reflectarray antenna with low cross-polarization based on nonradiative dielectric waveguide

This paper presents a wideband reflectarray antenna (RA) based on a nonradiative dielectric (NRD) waveguide with an inserted metal blade for muti-bit phase quantization. The proposed design eliminates the need of resonant components that typically exist in traditional RAs. Additionally, low cross-polarization is achieved by exciting the appropriate propagation mode in NRD waveguide. The beam scanning performance based on multi-bit phase quantization is verified by a series of static prototypes. Compared to traditional rectangular waveguide RAs, the proposed design possesses collimated beam scanning up to 60° without grating lobes, due to the compact unit cell dimensions. At a collimation beam angle of 20°, a 1-dB gain bandwidth of 18 % is achieved with an aperture efficiency of over 40 % and a cross-polarization level of below −40 dB.

In-situ synchrotron X-ray diffraction investigation of martensite decomposition in Laser Powder Bed Fusion (L-PBF) processed Ti–6Al–4V

Laser powder bed fusion (L-PBF) processed Ti–6Al–4V components present two substantial challenges: the presence of tensile residual stress and brittleness of the as-fabricated component due to the formation of the martensite (α′) phase. Industrially, post-heat treatment is performed to improve the quasi-static mechanical properties of the Ti–6Al–4V component through martensite (α′) decomposition and residual stress relaxation. However, detailed insights into the martensite decomposition and stress relaxation mechanisms are still lacking. To address this, in-situ high-energy synchrotron x-ray diffraction (HEXRD) was employed to simultaneously track: (I) martensite (α′) decomposition into a mixture of hexagonal α and body-centered cubic β phases, (II) residual stress relaxation process during heating. Rietveld refinement of 2D diffraction patterns recorded over a temperature range spanning from 25 to 1000°C revealed a three-stage evolution in the α′ unit cell parameters. Unit cell parameter analysis combined with the phase fraction analysis based on the diffraction patterns and the chemical composition profiles predicted by Thermocalc simulation gave detailed insight into the martensite (α′) decomposition process. In Stage 1 (until 375°C), the α′ phase unit cell exhibited linear expansion without indications of any phase transformation or stress relaxation. Upon commencement of stage II at 375°C, an increased expansion rate of the martensite (α′) unit cell was observed, attributed to the enhanced outward diffusion of vanadium (V), succeeded by β phase nucleation at 575°C. Simultaneously, during stage II, residual stress relaxation was observed at both macro and micro scale, culminating in a stress-free state achieved at approximately 750–800°C. Lastly, α-to-β phase transformation was observed in stage 3. The thermal evolution of the hexagonal unit cell dimensions was compared between martensitic and mill-annealed α+β microstructures. This comparison unraveled the link between the initial microstructure and the thermal expansion behavior of the hexagonal α′ and α phase.

Structural, spectroscopic, DFT studies, Hirshfeld surface analysis and antibacterial activity of Z-3-(4-bromophenyl)-3-chloroacrylaldehyde

The present paper describes the single-crystal X-ray structure of Z-3-(4-bromophenyl)-3-chloroacrylaldehyde (BCA). Hirshfeld Surface analysis was performed, providing insight into intermolecular interactions for the first time. The compound crystalizes in the monoclinic system with a space group P21/c and unit cell dimensions of a =3.9327(4) Å, b=18.5517(19), c=12.2749(14) and V=894.77(16)Å3. Z-3-(4-bromophenyl)-3-chloroacrylaldehyde was characterized using 13C and 1H NMR spectroscopy, and its thermal stability assessed with a thermogravimetric analyzer. Optical properties were investigated through UV-Visible absorption and emission spectroscopy. Density Functional Theory (DFT) calculations were performed using B3LYP theory with a basis set of SDD. HOMO-LUMO calculations, conceptual DFT and its global reactivity descriptors like hardness, electronegativity and electrophilicity of molecule were studied using G16W software. The energy gap of 4.17eV obtained from HOMO-LUMO molecular orbital energy shows that the compound is hard, stable and reactive. Further, Z-3-(4-bromophenyl)-3-chloroacrylaldehyde also exhibited significant antibacterial activity against both Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) with a zone of inhibition of 13 ± 1 mm against E. coli and 14 ± 1 mm against S. aureus and the MIC value was found to be 0.55 mg/mL against S. aureus and 1.1 mg/mL against E. coli. The integration of experimental and theoretical approaches in this study enhances the understanding of the versatile applications of BCA across various fields.

Synthesis, structural elucidation and characterization of a new organic single crystal Guanidinium adipate monohydrate (GuAM) for nonlinear optical applications

A slow evaporation solution growth process was employed to grow a new organic single crystal Guanidinium adipate monohydrate (GuAM) at room temperature. The structure refinement and cell specifications were elucidated using the X-ray diffraction method. Single crystal XRD study revealed that the grown crystal crystallized in the monoclinic system with unit cell dimensions a = 4.948 (9) Å; b = 16.770 (2) Å; c = 13.554 (2) Å; α and γ = 90.00⁰; β = 95.302⁰ (3), V = 1120.1(3) Å3 and Z = 4. The structure of the crystal was solved by direct method and refined by full matrix least-square method using SHELXL-2018/3 program. The crystalline nature of the sample was evaluated by powder X-ray diffraction (PXRD) study. Fourier transform infrared (FTIR) spectral study was employed to recognize the diverse functional groups present in the synthesized crystal. Optical attributes such as absorbance and emission nature of the GuAM were explored using UV–visible-NIR absorbance study and photoluminescence study respectively. The laser damage threshold value of the formed crystal has been determined by employing an Nd-YAG laser with a wavelength of 1064 nm. The mechanical nature of the GuAM was examined utilizing Vicker's microhardness test and other related parameters were also calculated. TGA-DTA analysis was utilized to estimate the title crystal's thermal stability. The Z-scan technique has been employed to gain insight into the third order nonlinear (NLO) parameters of the GuAM. These findings imply that guanidinium adipate monohydrate (GuAM), a grown single crystal, may be a viable choice for NLO applications.

Assimilation of surface pressure observations from personal weather stations in AROME-France

Abstract. Spatially dense surface pressure observations from personal weather stations (PWSs) are able to describe pressure patterns at the surface, such as those associated with convective events, in more detail than with standard weather stations (SWSs) only. In this study, the benefit of assimilating PWS observations with the 3DVar and the 3DEnVar data assimilation schemes of the AROME-France model is evaluated over a 1-month period and during a heavy precipitation event in the South of France. Observations of surface pressure from PWSs are bias-corrected, quality-controlled, and thinned with a spacing equal to the horizontal dimension of an AROME-France grid cell. Over France, almost half of the 55 187 available PWS observations are assimilated, which is 129 times more than the number of assimilated SWS observations. Despite the limited advantages found from their assimilation with the 3DVar assimilation scheme, the 3DEnVar assimilation scheme shows systematic improvement and reduces by 10.3 % the root-mean-square deviation in surface pressure between 1 h model forecasts and SWS observations over France. Significant improvement is observed over the first 9 h of the forecasts in mean sea level pressure. Finally, when PWS observations are assimilated with the 3DEnVar assimilation scheme, a surface pressure anomaly generated by a mesoscale convective system – observed by PWSs and not visible without them – is successfully assimilated. In that case, the forecasts of location and temporal evolution of the mesoscale convective system as well as rainfall are closer to the observations when PWS observations are assimilated.

Period induced reflectance tuning in transparent gold metasurfaces

Gold (Au) nanodisk arrays are modeled and fabricated for tunable near infrared reflectance with high visible transmittance. Simulations are performed in the visible and near infrared regimes between 400 and 2000 nm with varying period of nanostructures. A progressive increase in period of up to three times the diameter of the nanodisks on polymer and quartz substrates is presented. As a result, an increase in visible transmittance with a decrease in near infrared reflectance peak intensity is observed. Modeling results exhibit a high average visible transmittance of 91.5% (400–700 nm) and average reflectance of 62.9% (750–2000 nm) with diameter (D) variations from D=120 nm to D=500 nm with a period (P) equal to twice the diameter, P=2D for a polymer substrate. Electric field intensities exhibit an increase with a decrease in the period between individual nanostructures for constant unit cell dimensions. Alongside simulations, electron beam lithography and evaporation processes are utilized for the patterning and fabrication. Optical characterizations including scanning electron microscopy (SEM) and atomic force microscopy (AFM) of selected metasurfaces on quartz are performed. For a specific period and diameter, the fabricated metasurfaces exhibit near infrared reflectance having a good agreement with the simulated results about plasmonic wavelengths. Such metasurfaces offer potential to be deployed for applications that require selective reflectance intensities in the near infrared range with high visible transmittance, such as controlled environment agriculture (CEA) or multi spectral near infrared sensing. With tunability over a broadband (750–2500 nm), this simple and fabrication-friendly model may be used as a theoretical guide in quantifying specific design parameters with varying light intensity configurations.

Metasurfaces for sound absorption over a broad range of wave incidence angles

Control of reflected waves that meet surfaces from oblique directions is crucial, for instance, in closed spaces. Metasurfaces composed of Helmholtz resonators can be efficient and compact absorbers but have limited ability to achieve high absorption over a wide incidence angle range, especially when designed for high performance in the region approaching grazing incidence. In turn, sonic crystals can be used to manipulate wave propagation direction at low frequencies. We propose a type of absorber that combines a surface of 2D Helmholtz resonators and a 2D sonic crystal with cylindrical scatterers arranged in a hexagonal lattice. The combined effect of both structures yields a metasurface that can achieve high absorption over a broad range of incidence angles. Here, an analytic model to estimate the behavior of the absorbers for wavelengths that are much longer than the unit cell dimensions is presented. The model is used in combination with an optimization strategy to realize designs for single frequency and octave-band performance. The test cases show that surfaces with absorption coefficient values above 0.9 for the range of incidence angle extending from 0∘ until 83∘ can be realized. The performance of the absorbers is verified with a finite element model and experimentally.

Polarization insensitive multiband metamaterial absorber for bio-plastic sensing application

This article introduces a microwave multiband metamaterial absorber (MA) with high potential for bio-plastic sensing applications. The innovative design is realized through a compact unit cell dimension of 1.33λο × 1.33λο × 0.22λο, employing a state-of-the-art split-ring resonator structure. Strikingly, this absorber demonstrates polarization insensitivity and can be characterized by five distinct absorption peaks at 18.69 GHz, 23.34 GHz, 25.72 GHz, 32.94 GHz, and 35.40 GHz. The corresponding absorption rates are exceptionally high, ranging from 92.82% to 99.95%. To elucidate the underlying absorption mechanism, detailed analyses of the electric field, magnetic field, surface current distribution, and input impedance are provided, showcasing the absorber's effective MA structure. The designed MA sensor exhibits outstanding performance metrics for bio-plastic detection, including an average quality factor (Q-factor) of 210 and sensitivity of 0.888 GHz/RIU (refractive index unit), marking a significant advancement in the field. Additionally, the sensor's linearity, output variation, and sensitivity are considerably improved for bio-plastic sensing. The research confirms the proposed MA absorber's functionality by comparing measured results and simulation outcomes, indicating a high degree of accuracy and reliability. The potential applications of this MA are manifold, extending to microwave absorption and enhanced plastic sensing techniques. Its compact and thin design facilitates seamless integration with various sensor equipment, broadening the scope of its utility. Furthermore, the article delves into the relevance of this research to several Sustainable Development Goals (SDGs), particularly highlighting its alignment with SDG 9 (Industry, Innovation, and Infrastructure), SDG 12 (Responsible Consumption and Production), and SDG 14 (Life Below Water). Thus, the innovative MA design signifies a technological leap in the field of metamaterial absorbers and contributes to the pursuit of sustainability and environmental protection.

A New Mathematical Model for Cell Layout Problem considering Rotation of Unequal Dimensions of Cells and Machines

One of the main concepts in group technology (GT) is the cellular manufacturing system (CMS) with three main problems of cell formation (CF), cell layout (CL), and cell scheduling (CS). This paper studies the cell layout problem (CLP), aiming to find the optimal layout of machines within each cell (intracellular layout) and the optimal layout of cells in each workshop (intercellular layout). To adapt to reality, the dimensions of the cells and machines (inside each cell) were considered unequal, and also the cells and machines could rotate. We believe that a cellular layout that assumes unequal dimensions of the cells and machines can be used for batch production. This kind of production has a wide variety of low to medium demand. Furthermore, a cellular layout can be applied in CMSs and also in noncontinuous industries that have a job shop layout. Our main contribution is considering the possibility of rotating the cells and machines inside the cells. For this purpose, a mixed nonlinear programming model was developed to solve the CLP with the minimum cost of intracellular and intercellular material flows. The proposed nonlinear model was first converted into a linear model, and then a problem was generated and solved with GAMS software to validate the resulting linear model. This model finds the best layout of cells within the workshop and the best layout of machines inside each cell. Then, because of the NP-hardness of the CLP and the fact that even exact methods cannot solve large-scale examples in an acceptable computational time, an imperialist competitive algorithm (ICA) was designed and used to solve the problem. To evaluate the efficiency of the proposed algorithm, its numerical results in small dimensions were compared with the results of GAMS software. In large dimensions, 30 random problems were created, and the results of ICA were compared with the results of the particle swarm optimization (PSO) algorithm and genetic algorithm (GA). Finally, the parameters of the three meta-heuristic algorithms were set by the Taguchi method. Numerical results indicated that ICA was superior to both the PSO algorithm and GA. It could also achieve efficient solutions in a shorter computational time.

Structure of a novel form of phosphopantetheine adenylyltransferase from Klebsiella pneumoniae at 2.59Å resolution.

Phosphopantetheine adenylyltransferase (EC. 2.7.7.3, PPAT) catalyzes the penultimate step of the multistep reaction in the coenzyme A (CoA) biosynthesis pathway. In this step, an adenylyl group from adenosine triphosphate (ATP) is transferred to 4'-phosphopantetheine (PNS) yielding 3'-dephospho-coenzyme A (dpCoA) and pyrophosphate (PPi). PPAT from strain C3 of Klebsiella pneumoniae (KpPPAT) was cloned, expressed and purified. It was crystallized using 0.1M HEPES buffer and PEG10000 at pH 7.5. The crystals belonged to tetragonal space group P41212 with cell dimensions of a = b = 72.82Å and c = 200.37Å. The structure was determined using the molecular replacement method and refined to values of 0.208 and 0.255 for Rcryst and Rfree factors, respectively. The structure determination showed the presence of three crystallographically independent molecules A, B and C in the asymmetric unit. The molecules A and B are observed in the form of a dimer in the asymmetric unit while molecule C belongs to the second dimer whose partner is related by crystallographic twofold symmetry. The polypeptide chain of KpPPAT folds into a β/α structure. The conformations of the side chains of several residues in the substrate binding site in KpPPAT are significantly different from those reported in other PPATs. As a result, the modes of binding of substrates, phosphopantetheine (PNS) and adenosine triphosphate (ATP) differ considerably. The binding studies using fluorescence spectroscopy indicated a KD value of 3.45 × 10-4M for ATP which is significantly lower than the corresponding values reported for PPAT from other species.

Assessing the thermal conductivity of amorphous SiN by approach-to-equilibrium molecular dynamics.

First-principles molecular dynamics combined with the approach-to-equilibrium molecular dynamics methodology is employed to calculate the thermal conductivity of non-stoichiometric amorphous SiN. This is achieved by implementing thermal transients in five distinct models of different sizes along the direction of the heat transport. Such models have identical structural features and are representative of the same material, thereby allowing for a reliable analysis of thermal conductivity trends as a function of the relevant cell dimension. In line with the known physical law of heat propagation at short scale, the thermal conductivity increases in size with the direction of heat transport. The observed behavior is rationalized accounting for previous results on crystalline and amorphous materials, thus providing a unified description holding for a large class of materials and spanning a wide range of heat propagation lengths.