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This retrospective study evaluated the impact of orthodontic treatment on endodontically treated teeth. 32 teeth from 25 patients were analyzed, focusing on CBCT evaluations. All endodontic treatments utilized EDTA and 5.25% NaOCl in conjunction with Er:YAG laser-activated irrigation. Post-treatment assessment revealed that 21 teeth (66%) had root canal fillings of correspondent length, while 10 teeth (31%) were insufficient, and 1 tooth (3%) was uncertain. In terms of density and homogeneity, 25 teeth (78%) were classified as correspondent, 5 teeth (16%) as inadequate, and 2 teeth (6%) as uncertain. The periapical bone destruction probability index (PRI) demonstrated a significant increase in periapical destruction following orthodontic treatment. Specifically, the odds ratios for bone destruction were 1.67 (90% CI: 1.16–2.49, P=0.008) for present versus absent and 1.77 (90% CI: 1.11–2.85, P=0.031) for present versus uncertain. The proportion of teeth without periapical destruction decreased from 15 (14.9%) during treatment to 14 (23.9%) post-treatment. These findings highlight the critical relationship between endodontic quality and treatment outcomes, emphasizing the need for meticulous endodontics during orthodontic therapies.

Laser heating in a diamond anvil cell (DAC) is a common method for studying material behavior at high-pressure and high-temperature conditions. It has been previously proven that during continuous wave (CW) laser heating of a sample, carbon of the diamond anvils is mobilized, and its diffusion into the sample can lead to undesirable chemical reactions, which, if not detected, may cause misinterpretations of the results of the experiment. Minimizing the heating time with the use of a pulsed laser (PL) is thought to reduce the risk of possible carbon contamination of the sample; however, this has not been proven experimentally. Here, we report the results of our comparative study of the effect of pulsed and continuous wave (CW) laser heating on the mobilization of carbon and its chemical interaction with iron in a diamond anvil cell. Using X-ray absorption near edge structure spectroscopy, Synchrotron Mössbauer Source spectroscopy, and Synchrotron X-ray diffraction, we examined iron samples that were laser heated in DACs in various pressure transmitting media (neon, argon, and potassium chloride). According to our results, the use of the PL heating does not prevent the sample from carbon contamination. A reaction between carbon and iron happens within a few seconds even at moderate temperatures. We found that one analytical technique was generally insufficient to fully characterize the phase composition of the laser-heated samples. [ABSTRACT FROM AUTHOR]

We have investigated the local and electronic structure of solid rubidium by means of x-ray absorption spectroscopy up to 101.0 GPa, thus doubling the maximum investigated experimental pressure. This study confirms the predicted stability of phase VI and was completed by the combination of two pivotal instrumental solutions. On one side, we made use of nanocrystalline diamond anvils, which, contrary to the more commonly used single crystal diamond anvils, do not generate sharp Bragg peaks (glitches) at specific energies that spoil the weak fine structure oscillations in the x-ray absorption cross section. Second, we exploited the performance of a state-of-the-art x-ray focussing device yielding a beam spot size of 5 × 5 μm², spatially stable over the entire energy scan. An advanced data analysis protocol was implemented to extract the pressure dependence of the structural parameters in phase VI of solid Rb from 51.2 GPa up to the highest pressure. A continuous reduction of the nearest neighbour distances was observed, reaching about 6% over the probed pressure range. We also discuss a phenomenological model based on the Einstein approximation to describe the pressure behaviour of the mean-square relative displacement. Within this simplified scheme, we estimate the Grüneisen parameter for this high pressure Rb phase to be in the 1.3-1.5 interval. [ABSTRACT FROM AUTHOR]

Nickel is the second most abundant element in the Earth's core. However, the properties of Fe‐Ni alloys are still poorly constrained under planetary cores conditions, in particular concerning the effect of Ni on the melting curve of Fe. Here we show that Ni alloying up to 36 wt% does not affect the melting curve of Fe up to 100 GPa. However, Ni strongly modifies the hexagonal‐closed‐packed/face‐centered‐cubic (hcp/fcc) phase boundary, pushing the hcp/fcc/liquid triple point of Fe‐20wt%Ni to higher pressures and temperatures. Our results allow constraining the triple point for Fe‐10wt%Ni, a composition relevant for the Earth interior, and point out a decrease of the melting temperature at core‐mantle boundary by 400 K with respect to pure Fe. A lower amount of light elements than previously predicted is thus required to reduce the crystallization temperature of core materials below that of a peridotitic lower mantle, in better agreement with geochemical observations. Plain Language Summary: The Earth's core is believed to be composed of Fe alloyed with Ni and several lighter elements. In this paper, we investigate the effect of Ni alloying on the Fe phase diagram. The main effect of Ni addition is to enlarge the pressure/temperature stability domain of the face‐centered‐cubic (fcc) phase with respect to the hexagonal‐closed‐packed (hcp) phase and to shift the hcp/fcc/liquid triple point to higher pressures and temperatures. This implies a depression of the melting curve of Fe‐Ni alloys by around 400 K at mantle boundary conditions, at Ni concentrations pertinent for the Earth interior. This consequently decreases the temperature of the liquidus for Fe alloys constituting the Earth's core, in turn implying a reduced amount of light elements than previously predicted. Key Points: Melting curve and phase diagram of Fe‐20wt%Ni and Fe‐36wt%Ni have been investigated by in situ X‐ray absorption up to 120 GPa and 3500 KNi alloying shifts the hcp/fcc/liquid triple point to higher pressures and temperaturesThe triple point for Fe‐10wt%Ni is predicted to be around 135 GPa and 3800 K fixing new benchmarks for the Earth's core composition [ABSTRACT FROM AUTHOR]

In this work, we use extended X-ray absorption fine structure (EXAFS) data collected using nano-polycrystalline diamond anvil cell to study the atomic arrangement in Zr–Cu metallic glass in high pressure (HP) conditions. To reveal the microscopic details of stress accommodation mechanism, we performed molecular dynamics (MD) simulations of the HP atomic arrangement. By comparing the experimental and the calculated Zr and Cu K-edge EXAFS signal we prove the realistic character of the computer simulations. A detailed geometrical analysis of the simulated atomic configurations shows that with increasing hydrostatic pressure the local structure of Zr–Cu amorphous alloy becomes gradually dominated by Cu-centred icosahedral structural motifs involving fivefold symmetry incompatible with crystalline ordering. The variation of the short-range order is attributed to preferential straining of mechanically soft bonds between zirconium atoms. [ABSTRACT FROM AUTHOR]

Chromium dioxide has been synthesized by direct combustion process between Cr and O2 in a diamond anvil cell at 14 GPa using laser heating. Addition of nitrogen into the reactants’ environment substantially facilitated the oxidation of Cr and resulted in the formation of an orthorhombic CaCl2-structured phase of CrO2 after laser heating at 37 GPa. High-pressure synchrotron x-ray diffraction and Raman spectroscopy measurements of quenched CrO2 samples at ambient temperature showed a tetragonal (rutile-type structure)-to-orthorhombic (CaCl2-type structure) phase transition at about 17 GPa. The first principle calculations reproduce well the experimentally observed pressure domains of the stability of the tetragonal and orthorhombic phases of CrO2. The calculations show that the orthorhombic CrO2 is also half-metallic and that the ferromagnetic arrangement of spins of d electrons persists in orthorhombic phase of CrO2 up to 56 GPa. [ABSTRACT FROM AUTHOR]

A review of some important technical challenges related toin situdiamond anvil cell laser heating experimentation at synchrotron X-ray sources is presented. The problem of potential chemical reactions between the sample and the pressure medium or the carbon from the diamond anvils is illustrated in the case of elemental tantalum. Preliminary results of a comparison between reflective and refractive optics for high temperature measurements in the laser-heated diamond anvil cell are briefly discussed. Finally, the importance of the size and relative alignment of X-ray and laser beams for quantitative X-ray measurements is presented. [ABSTRACT FROM PUBLISHER]

We present a combined high pressure Ni K-edge x-ray absorption and Raman spectroscopic investigation of β-Ni(OH). Extended x-ray absorption fine structure analysis reveals a progressive shrinking of the Ni–O and Ni–Ni bond distances with pressure. As pressure is increased, Raman data show a continuous hardening of the phonon modes associated with the vibration of Ni–O sublattice, whereas a systematic frequency softening is displayed by the hydroxyl (O–H) symmetric stretching mode. This contrasting behavior implies a gradual development of a lattice instability with pressure in nickel hydroxide. Under pressure hydrogen bonds become increasingly unstable mainly due to the displacement of H atoms around the Ni–O axis inducing a local-lattice instability may explain the structural, Raman and x-ray absorption results. [ABSTRACT FROM AUTHOR]

We have developed an experimental setup at the ESRF beamline ID12 dedicated to X-ray absorption and magnetic circular dichroism measurements at high pressure adapted for the tender X-ray energy range and compatible with low temperatures and with high magnetic field. The focused incoming X-ray beam passes through a thin diamond disk attached to a fully perforated diamond anvil and X-ray fluorescence photons from the sample are collected in back-scattering geometry through the same diamond disk. The pressure in the cell is measured using the ruby luminescence through a full diamond anvil. The highest pressure attainable with this diamond anvil cell (DAC) depends on the thickness of the diamond disk and it is above 16 GPa for a 80-μm thick plate and exceeds 4.5 GPa in the case of 30-μm diamond disk. Excellent performances of this setup in the tender X-ray range are illustrated with X-ray absorption near-edge structure studies of the phase transitions in KCl at the potassium and chlorine K-edges (3.61 and 2.82 keV, respectively) as well as in CdS at the sulfur K-edge (2.47 keV). This DAC together with a dedicated total fluorescence yield (TFY) detector could be mounted in the main heat exchanger of a cryostat and inserted in a bore of a superconducting magnet, this makes possible to perform X-ray magnetic circular dichroism (XMCD) experiments at low temperature, high magnetic field and high pressure. Feasibility of this approach is shown with the XMCD results obtained at the U M-edges in ferromagnetic superconductor UGe. [ABSTRACT FROM PUBLISHER]

We present in this paper recent advances in the high pressure domain provided by the introduction of time-resolved energy-dispersive XAS (EDXAS) techniques at synchrotrons. We highlight technical aspects and describe two modes of acquisition: the ‘movie’ mode, where the time resolution is given by the detector acquisition speed and the ‘pump-and-probe’ mode, where the time resolution is given by the delay between the pump and the probe. These two modes define a frontier in the time resolution, respectively above and below the ∼10 μs regime. In the former, examples of applications are chemical stability and reactions at high pressure and high temperature or probing the warm dense matter regime using rapid current ramps. In the latter, an example is given on studies of dynamically compressed matter, by coupling single-bunch EDXAS at high-brilliance synchrotron to a nanosecond high-power laser. [ABSTRACT FROM PUBLISHER]

In this paper we present recent achievements in the field of investigation of the local, electronic and magnetic structure of the matter under extreme conditions of pressure and temperature. These results were obtained thanks to the coupling of a compact laser heating system to the energy-dispersive XAS technique available on the ID24 beamline at the ESRF synchrotron. The examples chosen concern the melting and the liquid structure of 3d metals and alloys under high pressures (HPs) and the observation of temperature-induced spin crossover in FeCO3at HP. [ABSTRACT FROM PUBLISHER]

Exosomes, belonging to the group of extracellular bodies, are released by healthy as well as cancerous cells and serve as a communication pathway. Tumor-derived exosomes (TEX) possess the capacity to reprogram the function of normal cells owing to their genetic and molecular cargo. Such exosomes target endothelial cells (among others) in the tumor microenvironment to promote angiogenesis. Blood supply is essential in solid tumor growth and metastasis. The potential of pro-angiogenic changes is enhanced by an increased amount of circulating tumor-derived exosomes in the body fluids of cancer patients. A vascular network is important, since the proliferation, as well as the metastatic spread of cancer cells depends on an adequate supply of oxygen and nutrients, and the removal of waste products. New blood vessels and lymphatic vessels are formed through processes called angiogenesis and lymphangiogenesis, respectively. Angiogenesis is regulated by both activator and inhibitor molecules. Thousands of patients have received anti-angiogenic therapy to date. Despite their theoretical efficacy, anti-angiogenic treatments have not proved beneficial in terms of long-term survival. Tumor-derived exosomes carrying pro-angiogenic factors might be a target for new anti-cancer therapy.

The European Synchrotron Radiation Facility has recently made available to the user community a facility totally dedicated to Time-resolved and Extreme-conditions X-ray Absorption Spectroscopy - TEXAS. Based on an upgrade of the former energy-dispersive XAS beamline ID24, it provides a unique experimental tool combining unprecedented brilliance (up to 1014 photons s−1 on a 4 µm × 4 µm FWHM spot) and detection speed for a full EXAFS spectrum (100 ps per spectrum). The science mission includes studies of processes down to the nanosecond timescale, and investigations of matter at extreme pressure (500 GPa), temperature (10000 K) and magnetic field (30 T). The core activities of the beamline are centered on new experiments dedicated to the investigation of extreme states of matter that can be maintained only for very short periods of time. Here the infrastructure, optical scheme, detection systems and sample environments used to enable the mission-critical performance are described, and examples of first results on the investigation of the electronic and local structure in melts at pressure and temperature conditions relevant to the Earth's interior and in laser-shocked matter are given. [ABSTRACT FROM AUTHOR]

BM23 is the general-purpose EXAFS bending-magnet beamline at the ESRF, replacing the former BM29 beamline in the framework of the ESRF upgrade. Its mission is to serve the whole XAS user community by providing access to a basic service in addition to the many specialized instruments available at the ESRF. BM23 offers high signal-to-noise ratio EXAFS in a large energy range (5-75 keV), continuous energy scanning for quick-EXAFS on the second timescale and a micro-XAS station delivering a spot size of 4 µm × 4 µm FWHM. It is a user-friendly facility featuring a high degree of automation, online EXAFS data reduction and a flexible sample environment. [ABSTRACT FROM AUTHOR]

Many Mössbauer spectroscopy (MS) experiments have used a rotating absorber in order to measure the second-order transverse Doppler (TD) shift, and to test the validity of the Einstein time dilation theory. From these experiments, one may also test the clock hypothesis (CH) and the time dilation caused by acceleration. In such experiments the absorption curves must be obtained, since it cannot be assumed that there is no broadening of the curve during the rotation. For technical reasons, it is very complicated to keep the balance of a fast rotating disk if there are moving parts on it. Thus, the Mössbauer source on a transducer should be outside the disk. Friedman and Nowik have already predicted that the X-ray beam finite size dramatically affects the MS absorption line and causes its broadening. We provide here explicit formulas to evaluate this broadening for a synchrotron Mössbauer source (SMS) beam. The broadening is linearly proportional to the rotation frequency and to the SMS beam width at the rotation axis. In addition, it is shown that the TD shift and the MS line broadening are affected by an additional factor assigned as the alignment shift which is proportional to the frequency of rotation and to the distance between the X-ray beam center and the rotation axis. This new shift helps to align the disk's axis of rotation to the X-ray beam's center. To minimize the broadening, one must focus the X-ray on the axis of the rotating disk and/or to add a slit positioned at the center, to block the rays distant from the rotation axis of the disk. Our experiment, using the 57Fe SMS, currently available at the Nuclear Resonance beamline (ID18) at the ESRF, with a rotating stainless steel foil, confirmed our predictions. With a slit installed at the rotation axis (reducing the effective beam width from 15.6 µm to 5.4 µm), one can measure a statistically meaningful absorption spectrum up to 300 Hz, while, without a slit, such spectra could be obtained up to 100 Hz only. Thus, both the broadening and the alignment shift are very significant and must be taken into consideration in any rotating absorber experiment. Here a method is offered to measure accurately the TD shift and to test the CH. [ABSTRACT FROM AUTHOR]

Double-sided laser heating (LH) combined with synchrotron X-ray radiation forin situstudies in the diamond anvil cell (DAC) has been the most productive and widely used high-temperature–high pressure technique in the past two decades. In the framework of the UPBL11 project (upgrade of ID24 beamline of European Synchrotron Radiation Facility), we developed a new on-line LH system for DACs. The preliminary optical scheme of the system is presented and discussed. Varying the settings, we are able to shape and to size the beam on the surface of the sample in the DAC. First pilot applications to the Fe case are shown. [ABSTRACT FROM AUTHOR]

We present a new design of a universal diamond anvil cell, suitable for different kinds of experimental studies under high pressures. Main features of the cell are an ultimate 90-degrees symmetrical axial opening and high stability, making the presented cell design suitable for a whole range of techniques from optical absorption to single-crystal X-ray diffraction studies, also in combination with external resistive or double-side laser heating. Three examples of the cell applications are provided: a Brillouin scattering of neon, single-crystal X-ray diffraction of α-Cr2O3, and resistivity measurements on the (Mg0.60Fe0.40)(Si0.63Al0.37)O3 silicate perovskite. [ABSTRACT FROM AUTHOR]

Abstract: Environmental considerations are receiving an increased amount of attention in both the residential and industrial sectors. In order to achieve a reduction in emissions of harmful substances to the air, water and land to meet national targets, industrial chemical producers must explore new avenues to reduce the impact that they have on the environment. Utilizing an optimization approach applied to an eco-park network allows for energy and materials to be conducted between network nodes in a manner that reduces emissions by utilizing process co-products and reduces the environmental and economic costs associated with transportation of feedstock and products. A small case eco-park is modelled in GAMS software to show the economic and environmental feasibility of this type of network and the approach to this type of problem. A dual-objective function is created in order to address the environmental concerns of the government and public while continuing to address economic factors presented by processing facilities. Exchanging materials and energy to reduce the life-cycle impact of the products allows for cost savings for the processor as well as reducing the emissions associated with the product; therefore, this type of arrangement is beneficial for producers as well as for society as a whole. [Copyright &y& Elsevier]

Despite a large number of studies of iron spin state in silicate perovskite at high pressure and high temperature, there is still disagreement regarding the type and P– T conditions of the transition, and whether Fe2+ or Fe3+ or both iron cations are involved. Recently, our group published results of a Mössbauer spectroscopy study of the iron behaviour in (Mg,Fe)(Si,Al)O3 perovskite at pressures up to 110 GPa (McCammon et al. ), where we suggested stabilization of the intermediate spin state for 8- to 12-fold coordinated ferrous iron ([8–12]Fe2+) in silicate perovskite above 30 GPa. In order to explore the behaviour in related systems, we performed a comparative Mössbauer spectroscopic study of silicate perovskite (Fe0.12Mg0.88SiO3) and majorite (with two compositions—Fe0.18Mg0.82SiO3 and Fe0.11Mg0.88SiO3) at pressures up to 81 GPa in the temperature range 296–800 K, which was mainly motivated by the fact that the oxygen environment of ferrous iron in majorite is quite similar to that in silicate perovskite. The [8–12]Fe2+ component, dominating the Mössbauer spectra of majorites, shows high quadrupole splitting (QS) values, about 3.6 mm s−1, in the entire studied P– T region (pressures to 58 GPa and 296–800 K). Decrease of the QS of this component with temperature at constant pressure can be described by the Huggins model with the energy splitting between low-energy e g levels of [8–12]Fe2+ equal to 1,500 (50) cm−1 for Fe0.18Mg0.82SiO3 and to 1,680 (70) cm−1 for Fe0.11Mg0.88SiO3. In contrast, for the silicate perovskite dominating Mössbauer component associated with [8–12]Fe2+ suggests the gradual change of the electronic properties. Namely, an additional spectral component with central shift close to that for high-spin [8–12]Fe2+ and QS about 3.7 mm s−1 appeared at ~35 (2) GPa, and the amount of the component increases with both pressure and temperature. The temperature dependence of QS of the component cannot be described in the framework of the Huggins model. Observed differences in the high-pressure high-temperature behaviour of [8–12]Fe2+ in the silicate perovskite and majorite phases provide additional arguments in favour of the gradual high-spin—intermediate-spin crossover in lower mantle perovskite, previously reported by McCammon et al. () and Lin et al. (). [ABSTRACT FROM AUTHOR]

High-pressure studies of (MgogFeo.1)2SiO4 olivine were performed at ambient temperature using X-ray diffraction, Raman spectroscopy, and Mössbauer spectroscopy. At ~--~4O GPa, a change of compressibility associated with saturation of the anisotropic compression mechanism was detected. This change is interpreted to result from the appearance of Si207 dimer defects, as deduced from Raman spectroscopy; the appearance of such defects also accounts for the previously reported pressure-induced amorphization observed for this material upon additional compression. Furthermore, this behavior is followed by a spin crossover of Fe2~ that occurs over a wide pressure range, as revealed by MOssbauer spectroscopy. [ABSTRACT FROM AUTHOR]

Magnetic and structural phase relations in FeO and MnO were studied in situ using Mössbauer spectroscopy, X-ray and neutron powder diffraction at high pressures and over a broad temperature range. Two principal transition boundaries were mapped: antiferromagnetic ordering (the Néel transition) and the structural distortion from the cubic B1 to a rhombohedral rB1 lattice. These two transitions are not necessarily coupled and the relations between the structural and magnetic properties of transition metal monoxides are discussed. [ABSTRACT FROM AUTHOR]

Newly installed, at Bayerisches Geoinstitut, X-ray system consists of three major components: RIGAKU FR-D high-brilliance source, Osmic's Confocal Max-Flux optics, and SMART APEX 4K CCD area detector. We tested the system for single-crystal structural studies on example of garnet, Co3Al2Si3O12, for powder diffraction analysis on example of a small sample of boron carbide, B4C, recovered after treatment in a multi-anvil apparatus, and for in situ experiments at high pressure on example of FeO compressed in a diamond anvil cell to>100 GPa. In all the cases, the system demonstrated its reliability and provided results comparable with those obtained using the best currently available instruments. Using a new X-ray system, we measured the compressibility of superhard nanocrystalline diamond at pressures up to 26 GPa and found it to be extremely incompressible with KT=488(4) GPa, K'=3.1(2), and V0=3.401(6) cm3/mol. [ABSTRACT FROM AUTHOR]

Some general results on Lie algebras of first order differential operators in n real variables with polynomial (degree ≤3) coefficients are demonstrated. An infinite family of specific Lie algebras and the corresponding Lie groups are described. [ABSTRACT FROM AUTHOR]