Search

The article presents the results of studies of the chemical composition, crystal structure, lattice parameters, microstructure, the valence state of the europium ion (at 300 K), electrical resistivity, and differential thermopower (6–400 K) of samples in the Eu(Cu1 − xAgx)2Si2 (0 ≤ x ≤ 1) substitutional solid solutions. A transition of the europium ion from the valence-stable state of Eu2+ in EuAg2Si2 to the state of intermediate (homogeneous) valence (IV) of the europium ion in EuCu2Si2 with an effective valence ϑeff = 2.41 (300 K) has been initiated by a successive replacement of silver atoms by copper atoms. With appropriate sample compositions, the transition passes through a Kondo-type state. The research subject is the patterns of transformations (when the composition of the sample changes), the electronic state, and, accordingly, the electronic transport properties. The simultaneous coexistence of europium ions in different electronic states is assumed. The substitutional solid solution Eu(Cu1 − xAgx)2Si2 (0 ≤ x ≤ 1) exhibits properties related to the competition between the state of the Kondo system, intermediate valence (IV), and magnetic ordering. [ABSTRACT FROM AUTHOR]

Intelligent materials occupy a special place among the huge number of known materials and those, which are being created all the time. Despite the impressive number of publications, no attempt has yet been made to classify compounds with a valence-unstable rare-earth element (R.E.) as smart materials. In this review paper, we show that the valence of the R.E. in some compounds can be changed by external and internal factors, such as temperature, pressure, changes in the occupation of d- and f-levels, and changes in the coordination polyhedra of atoms. Changing the valence of the R.E. may significantly alter the electrical and magnetic properties of compounds. [ABSTRACT FROM AUTHOR]

To assess the prevalence of pelvic pain worsened by orgasm in patients with endometriosis and its associated clinical features, focusing on those related to pelvic floor myalgia, central sensitization, and surgical findings. Prospectively collected data were analysed. Data were collected at three timepoints: pre-appointment patient questionnaire, initial appointment, and surgery. Surgery was done by gynecologists specializing in endometriosis. Tertiary referral centre for pelvic pain and endometriosis. Participants included were aged 18 to 50, pre-menopausal, diagnosed with endometriosis via specified criteria, and underwent surgery at our centre. A total of 358 participants referred to our centre between January 2018 and December 2019 completed the study. The median follow-up (duration between pre-appointment questionnaire and surgery) was 6 months, range 0-28 months. Participants who reported that orgasm worsened their pelvic or lower abdominal pain were compared to those who did not. Among 358 participants, 14% (n=49) reported pelvic pain worsened by orgasm. Pain with orgasm was significantly associated with pelvic floor myalgia (p = 0.01), higher scores on the Central Sensitization Inventory (p < 0.001), Patient Health Quality-9 (p < 0.001), and Generalized Anxiety Disorder-7 (p = 0.002). For surgical findings, there was no difference between the two groups for revised American Society for Reproductive Medicine scores (p=0.07). There was a trend towards ovarian endometriosis more commonly seen in participants without orgasm-associated pain (p=0.049). However, the prevalence of superficial peritoneal endometriosis, deep infiltrating endometriosis, and cul-de-sac obliteration were similar between the two groups. Pelvic pain worsened by orgasm in people with endometriosis may be associated with concurrent pelvic floor myalgia and central sensitization. Interventions targeting these factors may alleviate the symptom. There were no associations with more anatomically severe endometriosis found at surgery. Further research is needed to identify effective treatments. [ABSTRACT FROM AUTHOR]

We have obtained X-ray emission spectra of Ga and Ge in Ca3Ga2Ge4O14, X-ray emission OKα-spectra in Ca3Ga2Ge4O14, Ca3Ga2Ge4O14 + Ce3%, and Ca3Ga2Ge4O14 + Eu4% and Xray photoelectron spectra in Ca3Ga2Ge4O14 . Our X-ray spectral studies of the Ca3Ga2Ge4O14 gallogermanate have shown that the top of the valence band near the Fermi level is formed mainly by p states of gallium and germanium as well as p states of oxygen, whose intensity is sufficiently low. The middle of the valence band is formed by gallium 3d states with oxygen 2s states lying below them. These states are hybridized with 4p states of gallium and germanium because of which there are Kβ′′-satellites in the Kβ2-subbands of gallium and germanium. The bottom of the valence band is formed by 3d states of germanium, whose contribution to chemical bonding is insignificant. The X-ray emission bands of Ga and Ge in Ca3Ga2Ge4O14 and the photoelectron spectrum of the valence electrons of Ca3Ga2Ge4O14 are in good agreement. The OKα-band changes its fine structure only slightly upon doping Ca3Ga2Ge4O14 with Ce or Eu. The investigations of intrinsic luminescence under X-rays excitation of Ca3Ga2Ge4O14 gallogermanate are presented. [ABSTRACT FROM AUTHOR]

Ternary intermetallic R5Fe6Sn18 (R = Tm, Lu) compounds have been synthesized from the elements by arc melting, annealed at 670 K and characterized by X-ray powder diffraction and energy dispersive X-ray analyses. Performed structure refinements have shown that they crystallize in the cubic Tb5Rh6Sn18 structure type (space group Fm-3m, a = 13:55399(4) Å, a = 133.53243(5) Å for Tm and Lu compounds, respectively). Using 57Fe Mössbauer spectroscopy it has been found that the magnetic state of the Fe atoms in the Tm5Fe6Sn18 and Lu5Fe6Sn18 stannides is paramagnetic. The value of the isomer shifts for Lu5Fe6Sn18 and Tm5Fe6Sn18 is positive relative to pure Fe. The 57Fe Mössbauer spectra for Lu5Fe6Sn18 and Tm5Fe6Sn18 stannides have shown that the quadrupole splitting for the Fe position (24e) have magnitudes of 0.43 and 0.45 mm/s, respectively. The similarity of these values is consistent with a qualitative crystal structure analysis. The examined Tm5Fe6Sn18 and Lu5Fe6Sn18 compounds have been found to be characterized by metallic-like conductivity and high values of electrical resistivity (672.9 μΩ cm, 623.8 μΩ cm at 300 K for Tm and Lu, respectively). [ABSTRACT FROM AUTHOR]

The valence band electronic structure of HfFe2Si2 has been established for the first time based on X-ray emission spectroscopy measurements. The band structure and X-ray emission spectra have been also obtained theoretically using the ab initio LMTO method in the non-relativistic approximation. The electron configuration of Si in the compound HfFe2Si2 can be described as s1.1p1.5. The theoretical and experimental results are in satisfactory agreement. [ABSTRACT FROM AUTHOR]

Study Question: Does incisional endometriosis (IE) harbor somatic cancer-driver mutations?Summary Answer: We found that approximately one-quarter of IE cases harbor somatic-cancer mutations, which commonly affect components of the MAPK/RAS or PI3K-Akt-mTor signaling pathways.What Is Known Already: Despite the classification of endometriosis as a benign gynecological disease, it shares key features with cancers such as resistance to apoptosis and stimulation of angiogenesis and is well-established as the precursor of clear cell and endometrioid ovarian carcinomas. Our group has recently shown that deep infiltrating endometriosis (DE), a form of endometriosis that rarely undergoes malignant transformation, harbors recurrent somatic mutations.Study Design, Size, Duration: In a retrospective study comparing iatrogenically induced and endogenously occurring forms of endometriosis unlikely to progress to cancer, we examined endometriosis specimens from 40 women with IE and 36 women with DE. Specimens were collected between 2004 and 2017 from five hospital sites in either Canada, Germany or the Netherlands. IE and DE cohorts were age-matched and all women presented with histologically typical endometriosis without known history of malignancy.Participants/materials, Setting, Methods: Archival tissue specimens containing endometriotic lesions were macrodissected and/or laser-capture microdissected to enrich endometriotic stroma and epithelium and a hypersensitive cancer hotspot sequencing panel was used to assess for presence of somatic mutations. Mutations were subsequently validated using droplet digital PCR. PTEN and ARID1A immunohistochemistry (IHC) were performed as surrogates for somatic events resulting in functional loss of respective proteins.Main Results and the Role Of Chance: Overall, we detected somatic cancer-driver events in 11 of 40 (27.5%) IE cases and 13 of 36 (36.1%) DE cases, including hotspot mutations in KRAS, ERBB2, PIK3CA and CTNNB1. Heterogeneous PTEN loss occurred at similar rates in IE and DE (7/40 vs 5/36, respectively), whereas ARID1A loss only occurred in a single case of DE. While rates of detectable somatic cancer-driver events between IE and DE are not statistically significant (P > 0.05), KRAS activating mutations were more prevalent in DE.Limitations, Reasons For Caution: Detection of somatic cancer-driver events were limited to hotspots analyzed in our panel-based sequencing assay and loss of protein expression by IHC from archival tissue. Whole genome or exome sequencing, or epigenetic analysis may uncover additional somatic alterations. Moreover, because of the descriptive nature of this study, the functional roles of identified mutations within the context of endometriosis remain unclear and causality cannot be established.Wider Implications Of the Findings: The alterations we report may be important in driving the growth and survival of endometriosis in ectopic regions of the body. Given the frequency of mutation in surgically displaced endometrium (IE), examination of similar somatic events in eutopic endometrium, as well as clinically annotated cases of other forms of endometriosis, in particular endometriomas that are most commonly linked to malignancy, is warranted.Study Funding/competing Interest(s): This study was funded by a Canadian Cancer Society Impact Grant [701603, PI Huntsman], Canadian Institutes of Health Research Transitional Open Operating Grant [MOP-142273, PI Yong], the Canadian Institutes of Health Research Foundation Grant [FDN-154290, PI Huntsman], the Canadian Institutes of Health Research Project Grant [PJT-156084, PIs Yong and Anglesio], and the Janet D. Cottrelle Foundation through the BC Cancer Foundation [PI Huntsman]. D.G. Huntsman is a co-founder and shareholder of Contextual Genomics Inc., a for profit company that provides clinical reporting to assist in cancer patient treatment. R. Aguirre-Hernandez, J. Khattra and L.M. Prentice have a patent MOLECULAR QUALITY ASSURANCE METHODS FOR USE IN SEQUENCING pending and are current (or former) employees of Contextual Genomics Inc. The remaining authors have no competing interests to declare.Trial Registration Number: Not applicable. [ABSTRACT FROM AUTHOR]

In this study the comparison of dielectric behaviour of BaTi1-xZrxO3(BTZx) ceramic samples prepared by means of a solid state and mechanochemical synthesis was presented. A single phase of perovskite structure was identified in the samples at room temperature. No significant impurities were detected in an EDS spectrum and the samples had a good stoichiometric ratio. The morphology of the investigated samples was characterized by a scanning electron microscopy (SEM). The investigation of dielectric properties of the BTZx samples within the temperature range from 140 K to 600 K was performed by means of a dielectric spectroscopy method at the frequency ranging from 0.1 Hz to 10 MHz. The temperature dependences of real part of dielectric permittivity showed the changes of the character of the paraelectric–ferroelectric (PE–FE) phase transition for the ceramic samples obtained by means of both methods. [ABSTRACT FROM PUBLISHER]

Education, also the technical one, is supposed to prepare students for adult life, not only by providing them with ready-made knowledge, but first of all by equipping students with an ability to learn, gather and select information. Active methods influence students' senses, allowing for a better understanding and remembering the subject matter. The study shows some didactic methods used in technical education. The attention has been aid to inventive, exploratory, and inventive-exploratory methods. [ABSTRACT FROM AUTHOR]