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Despite decades of studies, a clear understanding of near-Tgphenomena remains challenging for glass-forming systems. This review delves into the intricate molecular dynamics of the small, heterocyclic thioether, 6-methyl-2,3-dihydro-1,4-benzodithiine (MeBzS2), with a particular focus on its near-Tgcold crystallization and relaxation mechanisms. Investigating isothermal crystallization kinetics at various temperatures reveals a significant interplay between its molecular dynamics and recrystallization from a supercooled liquid. We also identify two independent interconversion paths between energetically privileged conformers, characterized by strained transition states. We demonstrate that these spatial transformations induce substantial alterations in the dipole moment orientation and magnitude. Our investigation also extends to the complex salt PdCl2(MeBzS2), where we observe the transient conformers directly, revealing a direct relationship between their abundance and the local or macroscopic electric field. The initially energetically privileged isomers in an undisturbed system become less favored in the presence of an external electric field or ions, resulting even in an unexpected inversion of states. Consequently, we confirm the intramolecular character of secondary relaxation in MeBzS2and its mechanism related to conformational changes within the heterocyclic ring. The research is based on the combination of broadband dielectric spectroscopy, X-ray diffraction, and quantum density functional theory calculations.

The paper presents the temperature field effect on the dynamic stability problem of plates with imperfection. The main objective is to conduct numerical investigations which show the relations between the imperfection ratio and plate dynamic response in a thermal environment. The plate is composed of three layers: thin facings and a thicker core. The plate can be loaded mechanically and thermally or only thermally. The facings are mechanically compressed with the forces acting in a plane. The temperature field model is defined by the temperature difference, which occurs between the plate edges. Two plate models are examined as follows: built using the approximation methods – orthogonalization and finite differences – and composed of finite elements. The analytical and numerical solution procedure is the main one, which is the proposal to perform the problem analysis. The plate reaction is described by the obtained values of the critical temperature differences for plates loaded only thermally and by the critical mechanical loads and the corresponding temperature differences for plates loaded mechanically and subjected to the uncoupled temperature field. The effect of the plate imperfection ratio under time-dependent loads is shown by numerous observations and results, which are shown graphically. The importance of the imperfection ratio on the plate's dynamic stability response in complex loading conditions is studied.

Wide-angle X-ray scattering patterns were recorded for a series of aliphatic butanol isomers (n-, iso-, sec-, tert-butanol) and their phenyl derivatives (4-phenyl-1-butanol, 2-methyl-3-phenyl-1-propanol, 4-phenyl-2-butanol, and 2-methyl-1-phenyl-2-propanol, respectively) to determine their atomic-scale structure with particular emphasis on the formation of supramolecular clusters. In addition, molecular dynamics simulations were carried out and yielded good agreement with experimental data. The combination of experimental and theoretical results allowed clarification of the origin of the pre-peak appearing at low scattering angles for the aliphatic butanols and its absence for their phenyl counterparts. It was demonstrated that the location of the hydroxyl group in the molecule of alkyl butanol, its geometry, and rigidity determine the morphology of the supramolecular clusters, while the addition of the aromatic moiety causes more disordered organization of molecules. The phenyl group significantly decreases the number of hydrogen bonds and size of the supramolecular clusters formed via the O–H···O scheme. The lower association ability of phenyl alcohols via H-bonds is additionally attenuated by the appearance of competing π–π configurations evidenced by the structural models.

Piezo proteins are mechanically activated ion channels, which are required for mechanosensing functions in a variety of cell types. While we and others have previously demonstrated that the expression of Piezo1in osteoblast lineage cells is essential for bone-anabolic processes, there was only suggestive evidence indicating a role of Piezo1 and/or Piezo2 in cartilage. Here we addressed the question if and how chondrocyte expression of the mechanosensitive proteins Piezo1 or Piezo2 controls physiological endochondral ossification and pathological osteoarthritis (OA) development. Mice with chondrocyte-specific inactivation of Piezo1 (Piezo1Col2a1Cre), but not of Piezo2, developed a near absence of trabecular bone below the chondrogenic growth plate postnatally. Moreover, all Piezo1Col2a1Creanimals displayed multiple fractures of rib bones at 7 days of age, which were located close to the growth plates. While skeletal growth was only mildly affected in these mice, OA pathologies were markedly less pronounced compared to littermate controls at 60 weeks of age. Likewise, when OA was induced by anterior cruciate ligament transection, only the chondrocyte inactivation of Piezo1, not of Piezo2, resulted in attenuated articular cartilage degeneration. Importantly, osteophyte formation and maturation were also reduced in Piezo1Col2a1Cremice. We further observed increased Piezo1 protein abundance in cartilaginous zones of human osteophytes. Finally, we identified Ptgs2and Ccn2as potentially relevant Piezo1 downstream genes in chondrocytes. Collectively, our data do not only demonstrate that Piezo1 is a critical regulator of physiological and pathological endochondral ossification processes, but also suggest that Piezo1 antagonists may be established as a novel approach to limit osteophyte formation in OA.

Single crystal of Eu3+-doped cadmium molybdate (Cd0.9268▯0.0244Eu0.0488MoO4, where ▯ denotes cationic vacancies) has been successfully grown by the Czochralski method in air and under 1 MPa. X-ray diffraction analysis indicates that as-grown single crystal exhibits tetragonal scheelite-type structure (a = b = 5.16188(14) Å; c = 11.2080(5) Å; space group I41/a). Eu3+ions do not show long-range order and they are randomly distributed in CdMoO4framework substituting Cd2+ones. UV–vis diffuse reflectance measurements revealed very close optical band gap (Eg) values, i.e.∼1.74 eV along [100] and [001] crystallographic directions that are twice smaller than Egof microcrystalline pure CdMoO4as well as powder Eu3+-doped single crystal. Magnetic and electrical studies of Eu3+-doped cadmium molybdate single crystal showed a paramagnetic and n-type semiconducting behaviour with the metal-insulator transition above 350 K along both crystallographic directions. Dielectric results analysis using the Cole-Cole fit function revealed that the dipole relaxation process has different time scale depending on the crystallographic direction and exhibits Arrhenius temperature dependence for both studied directions. This fact is accompanied by the colossal dielectric permittivity with εr > 8⋅103. The above results are considered in the framework of narrow europium multiplets of energy comparable to thermal energy.

In women, aging leads to reduced hair density and thinner fibers and can result in female-pattern hair loss. However, the impact of the aging dermal environment on female scalp hair follicles remains unclear. In this study, we document in situ changes in 22 women (aged 19–81 years) and primary cultures of dermal fibroblast and dermal sheath cells. In situ, the papillary reticular boundary was indistinguishable in the young scalp but prominent in the scalp of those aged >40 years, accompanied by reduced podoplanin (PDPN) expression, increased versican expression, and changes in collagen organization. Hair follicles were shorter, not reaching the adipose layer. Hyaluronic acid synthase 2 was highly expressed, whereas matrix metalloproteinase 1 was elevated in the dermal papilla and dermal sheath in situ. Primary dermal fibroblast cultures confirmed that matrix metalloproteinase 1 mRNA, MMP1, increased with aging, whereas in dermal sheath cells, hyaluronic acid synthase 2, HAS2, and PDPNincreased and α-smooth muscle actin αSMAmRNA decreased. Both exhibited increased cartilage oligomeric protein, COMPmRNA expression. Proteomics revealed an increase in dermal sheath proteins in the dermal fibroblast secretome with aging. In summary, aging female scalp shows striking structural and biological changes in the hair follicle environment that may impact hair growth.

Herein, we investigated the molecular dynamics as well as intramolecular interactions in two primary monohydroxy alcohols (MA), 2-ethyl-1-hexanol (2EHOH) and n-butanol (nBOH), by means of broad-band dielectric (BDS) and Fourier transform infrared (FTIR) spectroscopy. The modeling data obtained from dielectric studies within the Rubinstein approach [Macromolecules2013, 46, 7525−7541] originally developed to describe the dynamical properties of self-assembling macromolecules allowed us to calculate the energy barrier (Ea) of dissociation from the temperature dependences of relaxation times of Debye and structural processes. We found Ea∼ 19.4 ± 0.8 and 5.3 ± 0.4 kJ/mol for the former and latter systems, respectively. On the other hand, FTIR data analyzed within the van’t Hoff relationship yielded the energy barriers for dissociation Ea∼ 20.3 ± 2.1 and 12.4 ± 1.6 kJ/mol for 2EHOH and nBOH, respectively. Hence, there was almost a perfect agreement between the values of Eaestimated from dielectric and FTIR studies for the 2EHOH, while some notable discrepancy was noted for the second alcohol. A quite significant difference in the activation barrier of dissociation indicates that there are probably supramolecular clusters of varying geometry or a ring-chain-like equilibrium is strongly affected in both alcohols. Nevertheless, our analysis showed that the association/dissociation processes undergoing within nanoassociates are one of the main factors underlying the molecular origin of the Debye process, supporting the transient chain model.

Herein, we report phase diagram, equation of state, and pressure-induced changes in the dielectric properties of acetamidinium manganese formate—a model organic–inorganic hybrid compound. A combination of structural and high-pressure dielectric studies showed a significant linear increase of phase-transition temperature by 85(1) K/GPa, slowdown of the molecular dynamics of acetamidinium cations (Ace+) and crystal lattice distortions under rising hydrostatic pressure. Moreover, we showed that the external pressure exerts a much less pronounced effect on the dynamics of the reorientational motions of Ace+moieties than temperature lowering, and furthermore, it acts, to a different extent, on acetamidinium cations and the organic–inorganic cavern skeleton.

Metal-formate frameworks comprising ammonium cations as guests are proven to be a fertile ground to study various phenomena associated with the temperature-induced changes in structural, dielectric, optical, and magnetic properties. In this contribution, we revisit NH4[Cu(HCOO)3], a member of metal formates that distinguishes itself in terms of its phase transition behavior and associated properties. New data on structural dynamics of all phases of NH4[Cu(HCOO)3]have been obtained with the use of variable-temperature Raman measurements. Smooth changes of band positions observed near 220 K attest to the postulated continuous nature of low-temperature phase transition, whereas apparent discontinuities at 355 K confirm the first-order type of transition between orthorhombic (II) and hexagonal (I) phases. Low-temperature Raman data were confronted with diffraction results, pointing to a significant effect of Jahn-Teller distortion on the vibrational properties the CuO6subnetwork. In the high-temperature range, a significant broadening of bands is observed, confirming that phase I is highly disordered, with the strongest changes of full width at half maximum (FWHM) parameters being observed for bands corresponding to NH4+cations. Dielectric investigations revealed the symmetric shape of the observed process indicating the Debye-like relaxation. Thus, the dielectric relaxation was characterized in terms of the dipolar relaxation model using the Cole–Cole relaxation function, leading to an Eavalue of approximately 0.76 eV. Finally, temperature-resolved second harmonic generation (SHG) measurements unequivocally corroborate the noncentrosymmetric setting of phases II and I, as well as allowed us to realize temperature-induced switching of second-order nonlinear optical (NLO) responses. We demonstrate that NH4[Cu(HCOO)3]serves as a host to uncommon kind of quadratic NLO switching, which takes advantage of two SHG-active states: SHG-highstate below Tc, and SHG-lowstate above Tc. The demonstrated SHG-high –SHG-lowtemperature-driven bistability stands out from the vast majority of molecular and coordination polymer NLO switches that employ binary SHG-onand SHG-offswitching schemes.

Gd3+-doped lead molybdato-tungstates with the chemical formula of Pb1−3x□xGd2x(MoO4)1−3x(WO4)3x(where x= 0.0455, 0.0839, 0.1430, corresponding to 9.53, 18.32, 33.37 mol% of Gd3+, respectively, as well as □ denotes cationic vacancies) were successfully synthesized via combustion route. The XRD and SEM results confirmed the formation of single-phase, tetragonal scheelite-type materials (space group I41/a) with the uniform, spherical and oval grains ranging from 5 to 20 µm. Individual grains are strongly agglomerated into big clusters with the size even above 50 µm. The magnetic measurements as well as the Brillouin fitting procedure showed paramagnetic state with characteristic superparamagnetic-like behaviour and the short-range ferromagnetic interactions. The electrical and broadband dielectric spectroscopy studies revealed insulating properties with the residual electrical n-type conduction of 2×10−9S/m and low energy loss (tanδ≈ 0.01) below 300 K. Dielectric analysis showed that no dipole relaxation processes in the Gd3+-doped materials were observed. A fit of dielectric loss spectra of Gd3+-doped samples by sum of the conductivity and the Havriliak-Negami, Cole-Cole, and Cole-Davidson functions confirmed this effect.

Infrared and dielectric spectroscopy, X-ray diffraction, and density functional theory computations have been used to study the hydrogen-bonding pattern, molecular dynamics, internal structure, and dipole moment distribution in 2-ethyl-1-hexanol, 2-ethyl-1-hexylamine, 2-ethyl-1-hexanethiol, and 1-phenyl-2-butanol. Dielectric investigations revealed that Kirkwood–Fröhlich correlation factor is much larger or lower than the unity in the vicinity of the glass transition, dependent on the compound. It indicates that change in the functionality of the H-bonding moiety influences the architecture of the supramolecular nanoassemblies. Further thorough experimental and theoretical considerations confirmed this hypothesis. Moreover, it was found that not the strength of hydrogen bonds itself, but the diverse population of nanoassociates, their size, and the spatial organization of the molecules in clusters have a strong influence on the appearance/absence as well as the intensity of the Debye relaxation. The results reported herein are of fundamental interest for a better understanding of the molecular origin of this characteristic process and impact of the molecular architecture, steric hindrance, and functionality on the nanoscale supramolecular assembling in various materials.

Molecular dynamics and transport coefficients change significantly around the so-called Arrhenius crossover in glass-forming systems. In this article, we revisit the dynamic processes occurring in a glass-forming macrocyclic crown thiaether MeBzS2Oabove its glass transition, revealing two crossover temperatures: TBat 309 and TAat 333 K. We identify the second one as the Arrhenius crossover that is closely related to the normal-to-supercooled liquid transition in this compound. We show that the transformation occurring at this point goes far beyond molecular dynamics (where the temperature dependence of structural relaxation times changes its character from activation-like to super-Arrhenius), being reflected also in the internal structure and diffraction pattern. In this respect, we found a twofold local organization of the nearest-neighbor molecules via weak van der Waals forces, without the formation of any medium-range order or mesophases. The nearest surrounding of each molecule evolves structurally in time due to the ongoing fast conformational changes. We identify several conformers of MeBzS2O, demonstrating that its lowest-energy conformation is preferred mainly at lower temperatures, i.e., in the supercooled liquid state. Its increased prevalence modifies locally the short-range intermolecular order and promotes vitrification. Consequently, we indicate that the Arrhenius transition is fuelled rather by conformational changes in this glass-forming macrocyclic crown thiaether, which is a different scenario from the so-far existing concepts. Our studies combine broadband dielectric spectroscopy (BDS), X-ray diffraction, Fourier transform infrared (FTIR) spectroscopy, molecular dynamics (MD) simulations, and density functional theory (DFT) calculations.

In this article, the effect of a porous material’s flexibility on the dynamic reversibility of a nonwetting liquid intrusion was explored experimentally. For this purpose, high-pressure water intrusion together with high-pressure in situ small-angle neutron scattering were applied for superhydrophobic grafted silica and two metal–organic frameworks (MOFs) with different flexibility [ZIF-8 and Cu2(tebpz) (tebpz = 3,3′,5,5′tetraethyl-4,4′-bipyrazolate)]. These results established the relation between the pressurization rate, water intrusion–extrusion hysteresis, and porous materials’ flexibility. It was demonstrated that the dynamic hysteresis of water intrusion into superhydrophobic nanopores can be controlled by the flexibility of a porous material. This opens a new area of applications for flexible MOFs, namely, a smart pressure-transmitting fluid, capable of dissipating undesired vibrations depending on their frequency. Finally, nanotriboelectric experiments were conducted and the results showed that a porous material’s topology is important for electricity generation while not affecting the dynamic hysteresis at any speed.

Dimethylammonium zinc formate [(CH3)2NH2][Zn(HCOO)3] (DMAZn) treated as a model dense metal–organic framework is a compound that has been intensively studied in the last decade. It undergoes a first-order order–disorder structural phase transition at T0∼ 167K, considered as the improper ferroelectric one. The complex mechanism of this phase transition is attributed to the ordering of the hydrogen bonds between (CH3)2NH2+(DMA+) and the formate groups as well as distortion of the zinc–formate framework. Here, the analysis of the impact of zinc substitution by Cu doping on the order–disorder phase transition is presented. The Jahn–Teller effect of Cu2+ions results in a local framework distortion, which consequently perturbs the structural dynamics. Based on the dielectric, thermal, structural, electron paramagnetic resonance, and IR spectroscopy measurements, it is shown that doping with Cu2+ions leads to a decrease of the phase transition entropy and temperature as well as a change in the nature of the phase transition.

The pin-on-disc dry sliding friction and wear experiments have been made on 42CrMo4 steel in contact with Si3N4, SiC, WC, Al2O3, and ZrO2ceramic balls. The tests were carried out at sliding speeds of 0.16 m/s, 0.24 m/s, and 0.32 m/s. During the tests, the friction force was monitored as a function of time. Discs and balls wear was measured after the tests using a white light interferometer Talysurf CCI Lite and Altisurf 520 optical profilometer with a CL1 confocal probe. To decrease variations in the experimental results, during the tests, wear debris was continuously removed from the disc surfaces. It was found out that with Al2O3counterpart the wear volume of the steel discs was the largest. However, the largest wear volume of the balls was observed for Si3N4ceramic balls.

We experimentally and numerically study the amplitude stability of an InAs/InGaAs quantum dot laser emitting simultaneously on ground states (GSs) and excited state (ESs) at center wavelengths of 1245 and 1168 nm, respectively. The stability is quantified by a spectrally resolved noise current analysis that is dependent on the laser injection current. We find a non-monotonic behavior of the amplitude noise which shows a reduction of up to 4 dB when the GS and ES emit simultaneously. Simulations based on a rate equation model confirm the reduction in noise and suggest the cascaded GS and ES carrier paths as the relevant underlying mechanism.

The paper presents the dynamic response of annular three-layered plate subjected to loads variable in time. The plate is loaded in the plane of outer layers. The plate core has the electrorheological properties expressed by the Bingham body model. The dynamic stability loss of plate with elastic core is determined by the critical state parameters, particularly by the critical stresses. Numerous numerical observations show the influence of the values of viscosity constant and critical shear stresses, being the Bingham body parameters, on the supercritical viscous fluid plate behaviour. The problem has been solved analytically and numerically using the orthogonalization method and finite difference method. The solution includes both axisymmetric and asymmetric plate dynamic modes.

We report a reduction of the relative intensity noise (RIN) in a dual-state emitting quantum-dot laser subject to the state-selective optical feedback on the ground state and excited state. Numerically, we map the evolution of the RIN for variations of the optical feedback phases for both states. We report important differences in the impact of the feedback when applied to the ground or excited state, and observe regimes for which a significant reduction in RIN is achieved. Experimentally, we confirm these results and achieve a 16 dB reduction of the RIN via a careful and independent tuning of the optical feedback phase for each state.

We present the assessment of birth body measurements of neonates born during the years 2011–2015 in one hospital maternity unit in the administrative region of Masovia. The measurements were compared against the WHO Child Growth Standards and the locally published reference standards.

This paper describes the tribological influence of surface topography on friction and wear under dry fretting gross slip regime in a point contact. Experiments were made using ball-on-disc tribotester in oscillatory motion. 100Cr6 sphere co-acted with a disc made of 42CrMo4 steel. During tests, the friction force was monitored as a function of time. Wear of discs and balls was measured after the tests using white light interferometer. Disc surfaces were prepared by various techniques, including milling, vapour blasting, polishing, lapping and grinding. Initial surface roughness height of discs, determined by the Sq parameter was in the range: 0.01–9μm. During tests, normal load was kept constant at 45N within the contact with frequency of 20Hz. Tests were carried out with different displacement amplitudes: 0.02, 0.05 and 0.075mm. It was found that initial surface roughness height had a significant influence on friction and wear.

This work is focused on the issue of non-measured points – one of the most important problems in surface texture measurements using optical methods. The fundamental aim of this research is to analyse errors of surface texture measurements caused by the presence of non-measured points. This study is divided into two parts. In the first part, circles with non-measured points were artificially created on peak portions of measured surfaces. In the second part – the results of measurement by a Talysurf CCI Lite interferometer were analysed. A measurement area of 3.3 × 3.3 mm contained 1024 × 1024 points. The measurements were performed with different intensity of light. Changes of parameters regarding the analysed errors depended on a surface type. The following parameters are susceptible to errors: skewness Ssk, areal material ratio Smr, as well as the following feature parameters: Spd, Sda, Sdv, Shaand Shv. Inaccuracies of measurement in valley parts of two-process textures led usually to larger errors of parameter computations compared with deviations in peak portions.

This paper presents the method of plasticity index calculation of isotropic two-process surfaces on the basis of index developed by Greenwood and Williamson for random surfaces of Gaussian ordinate distribution. This method was applied to computer generated isotropic two-process textures. The proposed plasticity index of two-process surface was compared with that of plateau surface and of the whole surface calculated by traditional manner. It was shown that plasticity index and generally the contact properties of two-process surfaces depended not only on plateau but also in a smaller degree on valley roughness. The method of estimation of summit radius of plateau surface from the analysis of two-process surface was presented too.

This paper presents the first experimental evidence of pronounced electrification effects upon reversible cycle of forced water intrusion–extrusion in nanoporous hydrophobic materials. Recorded generation of electricity combined with high-pressure calorimetric measurements improves the energy balance of {nanoporous solid + nonwetting liquid} systems by compensating mechanical and thermal energy hysteresis in the cycle. Revealed phenomena provide a novel way of “mechanical to electrical” and/or “thermal to electrical” energy transformation with unprecedented efficiency and additionally open a perspective to increase the efficiency of numerous energy applications based on such systems taking advantage of electricity generation during operational cycle.

This paper presents methods of separating the plateau part for various types of two-process profiles, having the traces of two processes. The traditional method based on the plateau-valley threshold, according to the ISO 13565-3 standard, is not always sufficient, since the valley portion can include plateau roughness. Starting and finishing points of each plateau in the measured profiles should be determined. The procedure found in the technical literature depends on setting not only the plateau-valley threshold but also a lower threshold. This approach was a little modified for profiles that contain both random and deterministic topography components. A new procedure of determination of the lower threshold was proposed for stratified profiles containing two deterministic parts. The valleys can be characterized by their widths and the distance between them. In addition, a description of the material probability curve is proposed.

A series of four alcohols, n-propanol and its halogen (Cl, Br, and I) derivatives, were selected to study the effects of variation in polarity and halogen-driven interactions on the hydrogen bonding pattern and supramolecular structure by means of experimental and theoretical methods. It was demonstrated on both grounds that the average strength of H-bonds remains the same but dissociation enthalpy, the size of molecular nanoassemblies, as well as long-range correlations between dipoles vary with the molecular weight of halogen atom. Further molecular dynamics simulations indicated that it is connected to the variation in the molecular order introduced by specific halogen-based hydrogen bonds and halogen–halogen interactions. Our results also provided important experimental evidence supporting the assumption of the transient chain model on the molecular origin of the structural process in self-assembling alcohols.