171 research outputs found

    Collapse of the hyperfine magnetic field at the Ru site in ferromagnetic rare earth intermetallics

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    The M\"{o}ssbauer Effect(ME) is frequently used to investigate magnetically ordered systems. One usually assumes that the magnetic order induces a hyperfine magnetic field, BhyperfineB_{hyperfine}, at the ME active site. This is the case in the ruthenates, where the temperature dependence of BhyperfineB_{hyperfine} at 99^{99}Ru sites tracks the temperature dependence of the ferromagnetic or antiferromagnetic order. However this does not happen in the rare-earth intermetallics, GdRu2_2 and HoRu2_2. Specific heat, magnetization, magnetic susceptibility, M\"{o}ssbauer effect, and neutron diffraction have been used to study the nature of the magnetic order in these materials. Both materials are found to order ferromagnetically at 82.3 and 15.3 K, respectively. Despite the ferromagnetic order of the rare earth moments in both systems, there is no evidence of a correspondingly large BhyperfineB_{hyperfine} in the M\"{o}ssbauer spectrum at the Ru site. Instead the measured spectra consist of a narrow peak at all temperatures which points to the absence of magnetic order. To understand the surprising absence of a transferred hyperfine magnetic field, we carried out {\it ab initio} calculations which show that spin polarization is present only on the rare-earth site. The electron spin at the Ru sites is effectively unpolarized and, as a result, BhyperfineB_{hyperfine} is very small at those sites. This occurs because the 4dd Ru electrons form broad conduction bands rather than localized moments. These 4dd conduction bands are polarized in the region of the Fermi energy and mediate the interaction between the localized rare earth moments.Comment: 34 pages -Revtex + 17 ps figure

    Pendekatan Deduktif Berbantuan Mind Mapping Terhadap Kemampuan Berpikir Kreatif Peserta Didik

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    The research aimed to know the effect of using learning video in liveworksheet towards students’ problem solving ability at SMAN 1 Bandar Lampung on environmental change material for class X of the 2021/2022 academic year. The research design used in this study is the non-equivalent control group design. The research took sample of 72 students consisting of class X MIPA 4 as a control class and X MIPA 5 as an experimental class with purposive sampling technique. Problem solving ability data obtained from pretest-posttest were analyzed using the Independent sample t-test analysis technique. The results showed that at the 0.05 significance level, the Sig. value was obtained. (2-tailed) 0.004 0.05. So it can be concluded that there is a significant effect of the use of learning videos in live worksheets towards the problem solving abilities of students on the material of environmental change.Penelitian ini bertujuan untuk menganalisis pengaruh video pembelajaran dalam Liveworksheet terhadap kemampuan pemecahan masalah siswa di SMAN 1 Bandar Lampung pada materi perubahan lingkungan pada kelas X semester genap tahun ajaran 2021/2022. Desain penelitian yang digunakan dalam penelitian ini  adalah Non equivalent control group design. Sampel penelitian berjumlah 72 peserta didik yang terdiri dari kelas X MIPA 4 sebagai kelompok kontrol dan X MIPA 5 sebagai kelompok eksperimen dengan teknik pengambilan sampel purposive sampling. Data kemampuan pemecahan masalah dianalisis menggunakan teknik analisis Independent sample t-test. Hasil penelitian menunjukan bahwa pada taraf signifikansi 0,05 didapatkan nilai Sig. (2-tailed) 0,004 0,05 sehingga dapat disimpulkan bahwa terdapat pengaruh yang signifikan dari penggunaan video pembelajaran dalam liveworksheet terhadap kemampuan pemecahan masalah siswa pada materi perubahan lingkungan.Kata kunci: kemampuan pemecahan masalah, liveworksheet, video pembelajaran DOI: http://dx.doi.org/10.23960/jbt.v10i2.2513

    Changes in capital allocation practices – ERM and organisational change

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    This paper aims to study changes in capital allocation routines following the introduction of a new risk management system, enterprise risk management (ERM). Based on an institutional framework and empirical evidence from multiple sources in a large UK insurance company, we evaluated the extent and nature of organisational change. ERM was seen as an external driver to the change in the existing routines, which in turn led to internal changes in new capital allocation routines. The change was extreme, which signifies that existing capital allocation routines were not strong enough to deal with ERM as a key driver of change

    Mouse brain distribution of a carbon-11 labeled vesamicol derivative: Presynaptic marker of cholinergic neurons

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    The regional mouse brain distribution of a new carbon-11 labeled derivative of vesamicol, [11C]-5-(N-methylamino)benzovesamicol ([11C]MABV) is reported. Radiotracer concentrations in vivo are in the rank order of striatum>cortex>hippocampus>hypothalamus> cerebellum, consistent with reported distributions of other presynaptic cholinergic neuronal markers. In time course studies, striatum/cerebellum and cortex/cerebellum ratios for (-)-[11C]MABV continue to increase to values of 13 and 5, respectively, 75 min after i.v. injection of [11C]MABV. The specific binding in striatum and cortex is lowered by pretreatment with (+/-)-vesamicol, and shows stereoselectivity with lower uptake and lower ratios for the (+)-enantiomer. (-)-[11C]MABV is proposed as a positron-emitting radioligand for the in vivo study of presynaptic cholinergic neurons.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28961/1/0000798.pd

    13-Series resolvins mediate the leukocyte-platelet actions of atorvastatin and pravastatin in inflammatory arthritis

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    This work was supported by funding from the European Research Council under the European Union’s Horizon 2020 research and innovation program (Grant 677542), a Sir Henry Dale Fellowship jointly funded by the Wellcome Trust and the Royal Society (Grant 107613/Z/15/Z), and the Barts Charity (Grant MGU0343). This work was also funded, in part, by Medical Research Council Advance Course Masters (Grant MR/J015741/1). The authors declare no conflicts of interest

    Site-Specific Labeling of Annexin V with F-18 for Apoptosis Imaging

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    Annexin V is useful in detecting apoptotic cells by binding to phosphatidylserine (PS) that is exposed on the outer surface of the cell membrane during apoptosis. In this study, we examined the labeling of annexin V-128, a mutated form of annexin V that has a single cysteine residue at the NH2 terminus, with the thiol-selective reagent 18F-labeling agent N-[4-[(4-[18F]fluorobenzylidene)aminooxy]butyl]maleimide ([18F]FBABM). We also examined the cell binding affinity of the 18F-labeled annexin V-128 ([18F]FAN-128). [18F]FBABM was synthesized in two-step, one-pot method modified from literature procedure. (Toyokuni et al., Bioconjugate Chem. 2003, 14, 1253−1259). The average yield of [18F]FBABM was 23 ± 4% (n = 4, decay-corrected) and the specific activity was ∼6000 Ci/mmol. The total synthesis time was ∼92 min. The critical improvement of this study was identifying and then developing a purification method to remove an impurity N-[4-[(4-dimethylaminobenzylidene)aminooxy]butyl]maleimide 4, whose presence dramatically decreased the yield of protein labeling. Conjugation of [18F]FBABM with the thiol-containing annexin V-128 gave [18F]FAN-128 in 37 ± 9% yield (n = 4, decay corrected). Erythrocyte binding assay of [18F]FAN-128 showed that this modification of annexin V-128 did not compromise its membrane binding affinity. Thus, an in vivo investigation of [18F]FAN-128 as an apoptosis imaging agent is warranted

    Raman spectroscopy in head and neck cancer

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    In recent years there has been much interest in the use of optical diagnostics in cancer detection. Early diagnosis of cancer affords early intervention and greatest chance of cure. Raman spectroscopy is based on the interaction of photons with the target material producing a highly detailed biochemical 'fingerprint' of the sample. It can be appreciated that such a sensitive biochemical detection system could confer diagnostic benefit in a clinical setting. Raman has been used successfully in key health areas such as cardiovascular diseases, and dental care but there is a paucity of literature on Raman spectroscopy in Head and Neck cancer. Following the introduction of health care targets for cancer, and with an ever-aging population the need for rapid cancer detection has never been greater. Raman spectroscopy could confer great patient benefit with early, rapid and accurate diagnosis. This technique is almost labour free without the need for sample preparation. It could reduce the need for whole pathological specimen examination, in theatre it could help to determine margin status, and finally peripheral blood diagnosis may be an achievable target

    Microcalcifications in breast cancer: novel insights into the molecular mechanism and functional consequence of mammary mineralisation.

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    BACKGROUND: Mammographic microcalcifications represent one of the most reliable features of nonpalpable breast cancer yet remain largely unexplored and poorly understood. METHODS: We report a novel model to investigate the in vitro mineralisation potential of a panel of mammary cell lines. Primary mammary tumours were produced by implanting tumourigenic cells into the mammary fat pads of female BALB/c mice. RESULTS: Hydroxyapatite (HA) was deposited only by the tumourigenic cell lines, indicating mineralisation potential may be associated with cell phenotype in this in vitro model. We propose a mechanism for mammary mineralisation, which suggests that the balance between enhancers and inhibitors of physiological mineralisation are disrupted. Inhibition of alkaline phosphatase and phosphate transport prevented mineralisation, demonstrating that mineralisation is an active cell-mediated process. Hydroxyapatite was found to enhance in vitro tumour cell migration, while calcium oxalate had no effect, highlighting potential consequences of calcium deposition. In addition, HA was also deposited in primary mammary tumours produced by implanting the tumourigenic cells into the mammary fat pads of female BALB/c mice. CONCLUSION: This work indicates that formation of mammary HA is a cell-specific regulated process, which creates an osteomimetic niche potentially enhancing breast tumour progression. Our findings point to the cells mineralisation potential and the microenvironment regulating it, as a significant feature of breast tumour development
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