We report a joint high-pressure experimental and theoretical study of the structural, vibrational, and photoluminescent properties of pure and Eu3+-doped cubic Y2O3 nanoparticles with two very different average particle sizes. We compare the results of synchrotron X-ray diffraction, Raman scattering, and photoluminescence measurements in nanoparticles with ab initio density-functional simulations in bulk material with the aim to understand the influence of the average particle size on the properties of pure and doped Y2O3 nanoparticles under compression. We observe that the high-pressure phase behavior of Y2O3 nanoparticles depends on the average particle size, but in a different way to that previously reported. Nanoparticles with an average particle size of ~37 nm show the same pressure-induced phase transition sequence on upstroke and downstroke as the bulk sample; however, nanoparticles with an average particle size of ~6 nm undergo an irreversible pressure-induced amorphization above 16 GPa that is completed above 24 GPa. On downstroke, 6 nm nanoparticles likely consist of an amorphous phase.
Background: Maximizing survival for patients with primary cutaneous melanomas (melanomas) depends on an early diagnosis and appropriate management. Several new drugs have been shown to improve survival in high-risk melanoma patients. Despite well-documented guidelines, many patients do not receive optimal management, particularly when considering patient age. Objective: to provide an update on melanoma management from the time of the decision to biopsy a suspicious skin lesion. Methods: We reviewed melanoma-management research published between 2018 and 2023 and identified where such findings impact and update the management of confirmed melanomas. Pubmed, Google Scholar, Ovid and Cochrane Library were used as search tools. Results: We identified 81 publications since 2017 that have changed melanoma management; 11 in 2018, 12 in 2019, 10 in 2020, 12 in 2021, 17 in 2022 and 18 in 2023. Discussion: Delayed or inaccurate diagnosis is more likely to occur when a partial shave or punch biopsy is used to obtain the histopathology. Wherever feasible, a local excision with a narrow margin should be the biopsy method of choice for a suspected melanoma. The Breslow thickness of the melanoma remains the single most important predictor of outcome, followed by patient age and then ulceration. The BAUSSS biomarker, (Breslow thickness, Age, Ulceration, Subtype, Sex and Site) provides a more accurate method of determining mortality risk than older currently employed approaches, including sentinel lymph node biopsy. Patients with metastatic melanomas and/or nodal disease should be considered for adjuvant drug therapy (ADT). Further, high-risk melanoma patients are increasingly considered for ADT, even without disease spread. Invasive melanomas less than 1 mm thick are usually managed with a radial excision margin of 10 mms of normal skin. If the thickness is 1 to 2 mm, select a radial margin of 10 to 20 mm. When the Breslow thickness is over 2 mm, a 20 mm clinical margin is usually undertaken. In situ melanomas are usually managed with a 5 to 10 mm margin or Mohs margin control surgery. Such wide excisions around a given melanoma is the only surgery that can be regarded as therapeutic and required. Patients who have had one melanoma are at increased risk of another melanoma. Ideal ongoing management includes regular lifelong skin checks. Total body photography should be considered if the patient has many naevi, especially when atypical/dysplastic naevi are identified. Targeted approaches to improve occupational or lifestyle exposure to ultraviolet light are important. Management also needs to include the consideration of vitamin D supplementary therapy.
This paper reports an experimental high-pressure study of natural mineral ferberite (FeWO4) up to 20 GPa using diamond-anvil cells. First-principles calculations have been used to support and complement the results of the experimental techniques. X-ray diffraction patterns show that FeWO4 crystallizes in the wolframite structure at ambient pressure and is stable over a wide pressure range, as is the case for other wolframite AWO4 (A = Mg, Mn, Co, Ni, Zn, or Cd) compounds. No structural phase transitions were observed for FeWO4, in the pressure range investigated. The bulk modulus (B0 = 136(3) GPa) obtained from the equation of state is very close to the recently reported value for CoWO4 (131(3) GPa). According to our optical absorption measurements, FeWO4 has an indirect band gap that decreases from 2.00(5) eV at ambient pressure to 1.56(5) eV at 16 GPa. First-principles simulations yield three infrared-active phonons, which soften with pressure, in contrast to the Raman-active phonons. These results agree with Raman spectroscopy experiments on FeWO4 and are similar to those previously reported for MgWO4. Our results on FeWO4 are also compared to previous results on other wolframite-type compounds.
The P-T phase diagram of the hydrated magnesium carbonate nesquehonite (MgCO3·3H2O) has not been reported in the literature. In this paper, we present a joint experimental and computational study of the phase stability and structural behavior of this cementitious material at high-pressure and high-temperature conditions using in situ single-crystal and synchrotron powder X-ray diffraction measurements in resistive-heated diamond anvil cells plus density functional theory calculations. Our results show that nesquehonite undergoes two pressure-induced phase transitions at 2.4 (HP1) and 4.0 GPa (HP2) at ambient temperature. We have found negative axial compressibility and thermal expansivity values, likely related to the directionality of the hydrogen bonds. The equations of state of the different phases have been determined. All the room-temperature compression effects were reversible. Heating experiments at 0.7 GPa show a first temperature-induced decomposition at 115 °C, probably into magnesite and a MgCO3·4H2O phase.
BACKGROUND: Melanoma disease patterns vary with patient age. AIM: To evaluate sentinel lymph node biopsy (SLNB) in managing melanoma at differing patient ages. METHODS: Online prediction tools were applied to compare SLNB positivity (SLNB+) and survival risk at patient ages 20-80. Tübingen melanoma data were used to determine variations in the hazard ratio of SLNB+ for mortality at different patient ages. RESULTS: Regardless of tumour thickness, predicted SLNB+ rates were markedly higher than mortality rates for 20-year-old patients. For 80-year-old patients, it is the opposite. DISCUSSION: If 1000 20-year-olds with a 0.4 mm thickness non-ulcerated melanoma underwent SLNB, 100 would likely be positive. If all 100 were to be offered adjuvant drug therapy (ADT), fewer than three more melanoma deaths in those 1000 patients would be avoided. In total, 97 patients would have received medication they may never have needed. If 1000 80-year-olds with a 3 mm thickness non-ulcerated melanoma underwent SLNB, only 40 would likely be positive. In total, 274 patients would be predicted to die of melanoma, 245 being SLNB negative and 29 SLNB+. ADT linked to SLNB+ could deny treatment to 89% of these high-risk patients. LIMITATIONS: The authors relied on published risk data. CONCLUSION: SLNB has poor specificity at predicting mortality in young melanoma patients and poor sensitivity in older patients. SLNB is not indicated in managing cutaneous melanoma for patients under 40 or over 60 years of age. Many such patients could be managed with wide local excision alone in their clinician's office-based practice. For all cutaneous melanoma patients at all ages, linking ADT to BAUSSS biomarker, (an algorithm of Breslow thickness, age, ulceration, subtype, sex and Site) rather than SLNB+ is likely more appropriate. BAUSSS provides a more accurate melanoma-specific mortality risk assessment for patients without burdening them with added surgery, hospitalization, costs or morbidity risk.
Melanoma , Sentinel Lymph Node , Skin Neoplasms , Humans , Middle Aged , Aged , Young Adult , Adult , Aged, 80 and over , Melanoma/pathology , Sentinel Lymph Node Biopsy , Skin Neoplasms/pathology , Neoplasm Staging , Sentinel Lymph Node/pathology , Prognosis , Retrospective Studies
The pressure-induced structural evolution of Ca2SnO4, Sr2SnO4, and Zn2SnO4 has been characterized by powder X-ray diffraction up to 20 GPa using the ALBA synchrotron radiation source and density functional theory calculations. No phase transition was observed in Ca2SnO4 and Zn2SnO4 in the investigated pressure range. The observation in Zn2SnO4 solves contradictions existing in the literature. In contrast, a phase transition was observed in Sr2SnO4 at a pressure of 9.09 GPa. The transition was characterized as from the ambient-condition tetragonal polymorph (space group I4/mmm) to the low-temperature tetragonal polymorph (space group P42/ncm). The linear compressibility of crystallographic axes and room-temperature pressure-volume equation of state are reported for the three compounds studied. Calculated elastic constants and moduli are also reported as well as a systematic discussion of the high-pressure behavior and bulk modulus of M2SnO4 stannates.
The effect of pressure on the structural, vibrational, and optical properties of lead thiogallate, PbGa2S4, crystallizing under room conditions in the orthorhombic EuGa2S4-type structure (space group Fddd), is investigated. The results from X-ray diffraction, Raman scattering, and optical-absorption measurements at a high pressure beyond 20 GPa are reported and compared not only to ab initio calculations, but also to the related compounds α'-Ga2S3, CdGa2S4, and HgGa2S4. Evidence of a partially reversible pressure-induced decomposition of PbGa2S4 into a mixture of Pb6Ga10S21 and Ga2S3 above 15 GPa is reported. Thus, our measurements and calculations show a route for the high-pressure synthesis of Pb6Ga10S21, which is isostructural to the stable Pb6In10S21 compound at room pressure.
The crystal structure of YbSbO4 was determined from powder X-ray diffraction data using the Rietveld method. YbSbO4 is found to be monoclinic and isostructural to α-PrSbO4. We have also tested the influence of pressure on the crystal structure up to 22 GPa by synchrotron powder X-ray diffraction. No phase transition was found. The P-V equation of state and axial compressibilities were determined. Experiments were combined with density-functional theory calculations, which provided information on the elastic constants and the influence of pressure in the crystal structure and Raman/infrared phonons. Results are compared with those from other orthoantimonates. Reasons for the difference in the high-pressure behaviour of YbSbO4 compared with most antimony oxides will be discussed.
The crystal structure of the CH3NH3PbBr3 perovskite has been investigated under high-pressure conditions by synchrotron-based powder X-ray diffraction. We found that after the previously reported phase transitions in CH3NH3PbBr3 (Pm3Ì mâIm3Ì âPmn21), which occur below 2 GPa, there is a third transition to a crystalline phase at 4.6 GPa. This transition is reported here for the first time contradicting previous studies, which reported amorphization of CH3NH3PbBr3 between 2.3 and 4.6 GPa. Our X-ray diffraction measurements show that CH3NH3PbBr3 remains crystalline up to at least 7.6 GPa, the highest pressure covered by experiments. The new high-pressure phase is also described by the space group Pmn21; however, the transition involves abrupt changes in the unit-cell parameters and a 3% decrease of the unit-cell volume. Our conclusions are confirmed by optical-absorption experiments, by visual observations, and by the fact that pressure-induced changes up to 10 GPa are reversible. The optical studies also allow for the determination of the pressure dependence of the band-gap energy, which is discussed using the structural information obtained from X-ray diffraction.
There are three areas of harmony in human life that are related to each other: "work environment", "love-to be loved-sexual area" and "social environment". Incompatibility and dissatisfaction in one area can also affect other areas. Therefore, the aim of this study is to examine the relationship between job satisfaction, life satisfaction, communication, and sexual satisfaction of healthcare employees. The data collected by questionnaires from 394 employees working in university hospitals in Turkey were analysed using SPSS and AMOS programs. The findings show that there is a positive relationship between the job and life satisfaction of employees of healthcare organizations. Additionally, the findings revealed that communication skills and sexual satisfaction have a mediating role between job satisfaction and life satisfaction of employees in healthcare organizations. Life satisfaction, sexual satisfaction, and relationships are some of the factors that should be considered by healthcare organizations. It would be beneficial to employees and the public if health policy makers implemented programmes to enhance job satisfaction.
We have studied by means of angle-dispersive powder synchrotron X-ray diffraction the structural behavior of KCaPO4, SrKPO4, and K2Ce(PO4)2 under high pressure up to 26, 25, and 22 GPa, respectively. For KCaPO4, we have also accurately determined the crystal structure under ambient conditions, which differs from the structure previously reported. Arguments supporting our structural determination will be discussed. We have found that KCaPO4 undergoes a reversible phase transition. The onset of the transition is at 5.6 GPa. It involves a symmetry decrease. The low-pressure phase is described by space group P3Ì m1 and the high-pressure phase by space group Pnma. For KSrPO4 and K2Ce(PO4)2, no evidence of phase transitions has been found up to the highest pressure covered by the experiments. For the three compounds, the linear compressibility for the different crystallographic axes and the pressure-volume equation of states are reported and compared with those of other phosphates. The three studied compounds are among the most compressible phosphates. The results of the study improve the knowledge about the high-pressure behavior of complex phosphates.
We report the structural behavior and compressibility of minrecordite, a naturally occurring Zn-rich dolomite mineral, determined using diamond-anvil cell synchrotron X-ray diffraction. Our data show that this rhombohedral CaZn0.52Mg0.48(CO3)2 carbonate exhibits a highly anisotropic behavior, the c axis being 3.3 times more compressible than the a axis. The axial compressibilities and the equation of state are governed by the compression of the [CaO6] and [ZnO6] octahedra, which are the cations in larger proportion in each layer. We observe the existence of a dense polymorph above 13.4(3) GPa using Ne as a pressure-transmitting medium, but the onset pressure of the phase transition decreases with the appearance of deviatoric stresses in nonhydrostatic conditions. Our results suggest that the phase transition observed in minrecordite is strain-induced and that the high-pressure polymorph is intimately related to the CaCO3-II-type structure. A comparison with other dolomite minerals indicates that the transition pressure decreases when the ratio Zn/Mg in the crystal lattice of pure dolomite is larger than 1. Density functional theory (DFT) calculations predict that a distorted CaCO3-II-type structure is energetically more stable than dolomite-type CaZn(CO3)2 above 10 GPa. However, according to our calculations, the most stable structure above this pressure is a dolomite-V-type phase, a polymorph not observed experimentally.
The vibrational and structural behaviors of Ni3V2O8 and Co3V2O8 orthovanadates have been studied up to around 20 GPa by means of X-ray diffraction, Raman spectra, and theoretical simulations. Both materials crystallize in an orthorhombic Kagomé staircase structure (space group: Cmca) at ambient conditions, and no phase transition was found in the whole pressure range. In order to identify the symmetry of the detected Raman-active modes under high pressure, single crystal samples of those materials were used in a polarized Raman and infrared setup. Moreover, high-pressure powder X-ray diffraction measurements were performed for Co3V2O8, and the results confirmed the structure stability also obtained by other diagnostic techniques. From this XRD analysis, the anisotropic compressibilities of all axes were calculated and the unit-cell volume vs pressure was fitted by a Birch-Murnaghan equation of state, obtaining a bulk modulus of 122 GPa.
Water in the mantle transition zone and the core-mantle boundary plays a key role in Earth's stratification, volatile cycling, and core formation. If water transportation is actively running between the aforementioned layers, the lower mantle should contain water channels with distinctive seismic and/or electromagnetic signatures. Here, we investigated the electrical conductivity and sound velocity of ε-FeOOH up to 71 GPa and 1800 K and compared them with global tomography data. An abrupt three-order jump of electrical conductivity was observed above 50 GPa, reaching 1.24(12) × 103 S/m at 61 GPa. Meanwhile, the longitudinal sound velocity dropped by 16.8% in response to the high-to-low spin transition of Fe3+. The high-conductivity and low-sound velocity of ε-FeOOH match the features of heterogenous scatterers in the mid-lower mantle. Such unique properties of hydrous ε-FeOOH, or possibly other Fe-enriched phases can be detected as evidence of active water transportation in the mid-lower mantle.
Wellbeing can be ensured in society through quality healthcare, a minimum of medical errors, and the improved performance of healthcare professionals. To this end, health information systems have been implemented in hospitals, with this implementation representing progress in medicine and information technologies. As a result, life expectancy has significantly increased, standards in healthcare have been raised, and public health has improved. This progress is influenced by the process of managing healthcare organizations and information systems. While hospitals tend to adapt health information systems to reduce errors related to patient misidentification, the rise in the occurrence and recording of medical errors in Lebanon resulting from failures to correctly identify patients reveals that such measures remain insufficient due to unknown factors. This research aimed to investigate the effect of health information systems (HISs) and other factors related to work-related conditions on reductions in patient misidentification and related consequences. The empirical data were collected from 109 employees in Neioumazloum Hospital in Lebanon. The results revealed a correlation between HISs and components and the effects of other factors on patient identification. These other factors included workload, nurse fatigue, a culture of patient safety, and lack of implementation of patient identification policies. This paper provides evidence from a Lebanese hospital and paves the way for further studies aiming to explore the role of information technologies in adopting HISs for work performance and patient satisfaction. Improved care for patients can help achieve health equality, enhance healthcare delivery performance and patient safety, and decrease the numbers of medical errors.
Health Information Systems , Humans , Medical Errors/prevention & control , Patient Safety , Lebanon , Delivery of Health Care
The high-pressure crystal structure evolution of CH3NH3PbBr3 (MAPbBr3) perovskite has been investigated by single-crystal X-ray diffraction and synchrotron-based powder X-ray diffraction. Single-crystal X-ray diffraction reveals that the crystal structure of MAPbBr3 undergoes two phase transitions following the space-group sequence: Pm3Ì m â Im3Ì â Pmn21, unveiling the occurrence of a nonpolar/polar transition (Im3Ì â Pmn21). The transitions take place at around 0.8 and 1.8 GPa, respectively. This result contradicts the previously reported phase transition sequence: Pm3Ì m â Im3Ì âPnma. In this work, the crystal structures of each of the three phases are determined from single-crystal X-ray diffraction analysis, which is later supported by Rietveld refinement of powder X-ray diffraction patterns. The pressure dependence of the crystal lattice parameters and unit-cell volumes are determined from the two aforementioned techniques, as well as the bulk moduli for each phase. The bandgap behavior of MAPbBr3 has been studied up to around 4 GPa, by means of single-crystal optical absorption experiments. The evolution of the bandgap has been well explained using the pressure dependence of the Pb-Br bond distance and Pb-Br-Pb angles as determined from single-crystal X-ray diffraction experiments.
A detailed study of lead halide-layered perovskites with general formula A2PbX4 (where A is cyclohexylammonium (CHA) or cyclopentylammonium (CPA) cation and X is Cl- or Br- anion) is presented. Using variable temperature synchrotron X-ray powder diffraction, we observe that these compounds exhibit diverse crystal structures above room temperature. Very interestingly, we report some unconventional thermomechanical responses such as uniaxial negative thermal expansion and colossal positive thermal expansion in a perpendicular direction. For the polymorphs of (CHA)2PbBr4, the volumetric thermal expansion coefficient is among the highest reported for any extended inorganic crystalline solid, reaching 480 MK-1. The phase transitions are confirmed by calorimetry and dielectric measurements, where the dielectric versus temperature curves show anomalies related with the order-disorder phase transitions. In addition, these compounds exhibit a broad photoluminescence (PL) emission with a large Stokes shift, which is related with an exciton PL emission.
The understanding of the interplay between crystal structure and electronic structure in semiconductor materials is of great importance due to their potential technological applications. Pressure is an ideal external control parameter to tune the crystal structures of semiconductor materials in order to investigate their emergent piezo-electrical and optical properties. Accordingly, we investigate here the high-pressure behavior of the semiconducting antiferromagnetic material ß-Cu2V2O7, finding it undergoes a pressure-induced phase transition to γ-Cu2V2O7 below 4000 atm. The pressure-induced structural and electronic evolutions are investigated by single-crystal X-ray diffraction, absorption spectroscopy and ab initio density functional theory calculations. ß-Cu2V2O7 has previously been suggested as a promising photocatalyst for water splitting. Now, these new results suggest that ß-Cu2V2O7 could also be of interest with regards to barocaloric effects, due to the low phase -transition pressure, in particular because it is a multiferroic material. Moreover, the phase transition involves an electronic band gap decrease of approximately 0.2 eV (from 1.93 to 1.75 eV) and a large structural volume collapse of approximately 7%.
