Structural and dielectric studies of the phase behaviour of the topological ferroelectric La1-xNdxTaO4

We thank the University of St Andrews and EPSRC (via DTG studentships to CALD and JG) for funding,The layered perovskite LaTaO4 has been prepared in its polar orthorhombic polymorphic form at ambient temperature. Although no structural phase transition is observed in the temperature interval 25° C < T < 500 °C, a very large axial thermal contraction effect is seen, which can be ascribed to an anomalous buckling of the perovskite octahedral layer. The non-polar monoclinic polymorph can be stabilised at ambient temperature by Nd-doping. A composition La0.90Nd0.10TaO4 shows a first-order monoclinic-orthorhombic (non-polar to polar) transition in the region 250° C < T < 350 °C. Dielectric responses are observed at both the above structural events but, despite the ‘topological ferroelectric’ nature of orthorhombic LaTaO4, we have not succeeded in obtaining ferroelectric P–E hysteresis behaviour. Structural relationships in the wider family of AnBnX3n+2 layered perovskites are discussed.Publisher PDFPeer reviewe

Estrogenic activity, race/ethnicity, and Indigenous American ancestry among San Francisco Bay Area women.

Estrogens play a significant role in breast cancer development and are not only produced endogenously, but are also mimicked by estrogen-like compounds from environmental exposures. We evaluated associations between estrogenic (E) activity, demographic factors and breast cancer risk factors in Non-Latina Black (NLB), Non-Latina White (NLW), and Latina women. We examined the association between E activity and Indigenous American (IA) ancestry in Latina women. Total E activity was measured with a bioassay in plasma samples of 503 women who served as controls in the San Francisco Bay Area Breast Cancer Study. In the univariate model that included all women with race/ethnicity as the independent predictor, Latinas had 13% lower E activity (p = 0.239) and NLBs had 35% higher activity (p = 0.04) compared to NLWs. In the multivariable model that adjusted for demographic factors, Latinas continued to show lower E activity levels (26%, p = 0.026), but the difference between NLBs and NLWs was no longer statistically significant (p = 0.431). An inverse association was observed between E activity and IA ancestry among Latina women (50% lower in 0% vs. 100% European ancestry, p = 0.027) consistent with our previously reported association between IA ancestry and breast cancer risk. These findings suggest that endogenous estrogens and exogenous estrogen-like compounds that act on the estrogen receptor and modulate E activity may partially explain racial/ethnic differences in breast cancer risk

Organisational routines and interfirm collaboration : measurement dilemmas and recommendations for further research steps

Purpose: The paper aims mainly to present the results and consequences of measurement inaccuracies and to make recommendations for further research. Design/Methodology/Approach: We began our research by providing studies on the theoretical origins of constructs in survey questions. Specifically, we studied the theorems and related constructs. We then reviewed the measurement of the constructs, selecting reliable scales. We conducted an initial study on 101 firms in Poland randomly selected from the high-technology sector, specifically the IT sector. We selected an industry in which inter-firm relationships are common. They are distinguished by high innovation, short product and process life cycles and therefor require many relationships to meet customer expectations. The respondents were top managers. The inclusive criterion was their employment of at least five employees. Collected data were analysed with Statistica 13 software (TIBCO Software Inc. (2017). Findings: After solving measurement dilemmas we made methodological recommendations regarding population structure and scales revealing particular constructs. Originality/Value: The implementation of the recommendations aforementioned would allow to formulate and verify hypotheses resulting from the propositions we have formulated while proposing our research framework. Additionally, we obtained a new Propensity to Collaborate scale as the questions referred to particular dimensions joined in quite different groups. Hence, one item has been deleted and the dimensions have been combined. We propose to check the new scale (without dimensions) in the future research.peer-reviewe

Lateral grating DFB AlGaInN laser diodes for optical communications and atomic clocks

AlGaInN laser diode technology is of considerable interest for telecom applications and next generation atomic optical clocks based on Sr (by using 422nm &amp; 461nm) and Rb at 420.2nm.Very narrow linewidths (&lt;1MHz) are required for such applications. We report lateral gratings on AlGaInN ridge waveguide laser diodes to achieve a single wavelength device with a good side mode suppression ratio (SMSR) that is suitable for atomic clock and telecom applications

Future direction of pathogenesis and treatment for rheumatic disorders

After the breakthrough in the treatment of rheumatoid arthritis and numerous related disorders with biological therapies targeting TNFa at the Kennedy Institute in London Millions of patients have tremendously benefitted. However, we cannot cure these diseases yet and have to search for additional therapeutic targets. Since it was shown that synovial fibroblasts (SF) are not only effector cells responding to inflammatory stimuli, but appear endogenously activated and potentially involved into spreading the disease [1], we searched for the epigenetic modifications leading to the activated phenotype of these cells. Epigenetics in its scientific definition “is the study of all heritable and potentially reversible changes in genome function that do not alter the nucleotide sequence within the DNA”, but might be considered in simpler terms as the regulation of gene expression. Epigenetic modifications include: Acetylation

Overexpression of toll-like receptors 3 and 4 in synovial tissue from patients with early rheumatoid arthritis: Toll-like receptor expression in early and longstanding arthritis

OBJECTIVE: To analyze the expression, regulation, and biologic relevance of Toll-like receptors (TLRs) 1-10 in synovial and skin fibroblasts and to determine the expression levels of TLRs 2, 3, and 4 in synovial tissues from patients with early rheumatoid arthritis (RA), longstanding RA, and osteoarthritis (OA). METHODS: Expression of TLRs 1-10 in RA synovial fibroblasts (RASFs), OASFs, and skin fibroblasts was analyzed by real-time polymerase chain reaction (PCR). Fibroblasts were stimulated with tumor necrosis factor alpha, interleukin-1beta (IL-1beta), bacterial lipopeptide, poly(I-C), lipopolysaccharide, and flagellin. Production of IL-6 was determined by enzyme-linked immunosorbent assay and induction of TLRs 2-5, matrix metalloproteinases (MMPs) 3 and 13 messenger RNA by real-time PCR. Expression of TLRs 2-4 in synovial tissues was analyzed by immunohistochemistry. RESULTS: Synovial fibroblasts expressed TLRs 1-6, but not TLRs 7-10. Among the expressed TLRs, TLR-3 and TLR-4 were the most abundant in synovial fibroblasts, and stimulation of synovial fibroblasts with the TLR-3 ligand poly(I-C) led to the most pronounced increase in IL-6, MMP-3, and MMP-13. In contrast, skin fibroblasts did not up-regulate MMP-3 or MMP-13 after stimulation with any of the tested stimuli. In synovial tissues from patients with early RA, TLR-3 and TLR-4 were highly expressed and were comparable to the levels of patients with longstanding RA. These expression levels were elevated as compared with those in OA. CONCLUSION: Our findings of high expression of TLRs, particularly TLRs 3 and 4, at an early stage of RA and the reactivity of synovial fibroblasts in vitro to TLR ligands suggest that TLR signaling pathways resulting in persistent inflammation and joint destruction are activated early in the disease process

Ethnic differences in ovulatory function in nulliparous women

African-American women have a long-standing approximately 20% higher breast cancer incidence rate than USA White women under age 40 while rates among Latinas are lower than those of Whites. The reasons for this are not clear, however they may be due to ethnic differences in circulating oestradiol and progesterone levels. In a cross-sectional study, we investigated whether anovulation frequency and circulating serum oestradiol and/or progesterone levels vary among normally cycling nulliparous African-American (n=60), Latina (n=112) and non-Latina White (n=69) women. Blood and urine specimens were collected over two menstrual cycles among healthy 17- to 34-year-old women. Frequency of anovulation was greater among White women (nine out of 63, 14.3%) than African-American women (four out of 56, 7.1%) or Latina women (seven out of 102, 6.9%), although these differences were not statistically significant. African-American women had 9.9% (P=0.26) higher follicular phase oestradiol concentrations than Latina women and 17.4% (P=0.13) higher levels than White women. African-American women also had considerably higher levels of luteal phase oestradiol (vs Latinas, +9.4%, P=0.14; vs Whites, +25.3%, P=0.003) and progesterone (vs Latinas, +15.4%, P=0.07; vs Whites, +36.4%, P=0.002). Latina women were also observed to have higher follicular oestradiol, and luteal oestradiol and progesterone levels than White women (follicular oestradiol: +6.8%, P=0.48; luteal oestradiol: +14.6%, P=0.04; luteal progesterone: +18.2%, P=0.06). These results suggest that exposure to endogenous steroid hormones may be greater for young African-American and Latina women than for Whites

The effect of finasteride on the prostate gland in men with elevated serum prostate-specific antigen levels.

Prostate cancer is a disease associated with androgens. It has been hypothesized that reducing the conversion of testosterone (T) to dihydrotestosterone (DHT) in the prostate by the use of the drug finasteride, a 5alpha-reductase inhibitor, will reduce the incidence of prostate cancer. We investigated the chemopreventive potential of finasteride by evaluating its effect on the prostate gland of men with elevated serum prostate-specific antigen (PSA). Fifty-two men with elevated PSA and prostate sextant biopsies negative for cancer were randomized to receive finasteride 5 mg day(-1) (27 patients) or no medication (25 patients) for 12 months and were rebiopsied at 12 months. The biopsies were evaluated for the presence of cancer, the proportion of glandular and hyperplastic tissue, and the presence of high-grade prostatic intraepithelial neoplasia (PIN). Epithelial proliferation was assessed in the prestudy and 12-month biopsies by immunohistochemistry using antibody to proliferating cell nuclear antigen (PCNA). Serum blood samples were drawn at baseline and after 1, 3, 6 and 12 months of study. In the control group, serum levels of PSA and T were unchanged throughout the 12 months. In the finasteride group, PSA decreased 48% (P < 0.001), DHT decreased 67% (P < 0.001) and T increased 21% (P < 0.001). Histological evaluation of prestudy and 12-month biopsy specimens revealed that the finasteride group had a 30% reduction in the percentage of hyperplastic epithelial tissue (P = 0.002), although this decrease was not statistically significantly different between the finasteride and control groups (P = 0.11). In patients with PIN on prestudy biopsy, no change occurred in the PIN lesions with finasteride treatment. Finasteride also had no effect on the proliferation index of prostatic epithelial cells. Of the 27 patients treated with finasteride, eight (30%) had adenocarcinoma of the prostate detected on the 12-month biopsy, compared with one (4%) of the control patients (P = 0.025). In the treatment group, six cancers occurred in the eight patients with PIN on the prestudy biopsy; in the observation group no cancers were detected in the five patients with PIN on the prestudy biopsy (P = 0.021). Two cancers occurred in the 19 men in the treatment group with no evidence of PIN on the prestudy biopsy, compared with one cancer in the 20 men in the observation group with no evidence of PIN on the prestudy biopsy (P = 0.60). This study, using a novel model for evaluating short-term efficacy of chemopreventive or therapeutic agents in men at high risk of prostate cancer, provides little evidence that finasteride is an effective chemopreventive agent for prostate cancer in men with elevated PSA