Nonresonant microwave absorption in epitaxial La-Sr-Mn-O films and its relation to colossal magnetoresistance

We study magnetic-field-dependent nonresonant microwave absorption and dispersion in thin La$_{0.7}$Sr$_{0.3}$MnO$_{3}$ films and show that it originates from the colossal magnetoresistance. We develop the model for magnetoresistance of a thin ferromagnetic film in oblique magnetic field. The model accounts fairly well for our experimental findings, as well as for results of other researchers. We demonstrate that nonresonant microwave absorption is a powerful technique that allows contactless measurement of magnetic properties of thin films, including magnetoresistance, anisotropy field and coercive field.Comment: 20 pages, 11 figure

A 31T split-pair pulsed magnet for single crystal x-ray diffraction at low temperature

We have developed a pulsed magnet system with panoramic access for synchrotron x-ray diffraction in magnetic fields up to 31T and at low temperature down to 1.5 K. The apparatus consists of a split-pair magnet, a liquid nitrogen bath to cool the pulsed coil, and a helium cryostat allowing sample temperatures from 1.5 up to 250 K. Using a 1.15MJ mobile generator, magnetic field pulses of 60 ms length were generated in the magnet, with a rise time of 16.5 ms and a repetition rate of 2 pulses/hour at 31 T. The setup was validated for single crystal diffraction on the ESRF beamline ID06

DTIC xenogenized lines obtained from an L1210 clone: clonal analysis of cytotoxic T lymphocyte reactivity.

Antineoplastic compounds can induce on tumour cells new antigens that undetectable on parental cells and which are transmissible as a genetic character. In this study mouse leukaemia L1210 was cloned in vitro by limiting dilution and one cloned line was recloned in vivo. Four subcloned tumour cell lines (A,D,R,S) were xenogenized in vivo by DTIC treatment (A/DTIC, D/DTIC, R/DTIC, S/DTIC) following a schedule previously described. Up to 10(7) cells of these xenogenized subclones, injected i.p., were rejected by syngeneic hosts, although they grew in immunosuppressed hosts. The DTIC treated subclones were lysed by in vivo-primed, in vitro-restimulated (with the relevant subclone) lymphocytes. The cytotoxic lymphocyte activity was not strictly specific since parental, DTIC-untreated cells were also lysed, although less efficiently. CTL directed against the D/DTIC subclone were cloned by limiting dilution. Ninety-four CTL clones were assayed against L1210 subcloned cells, DTIC-treated and untreated, and against different murine tumours (syngeneic or allogenic). Three specific antigens could be identified in the 51Cr release assay. The DTIC subclones expressed one antigen that was specifically recognized by a set of CTL clones. A number of CTL clones were able to lyse the L1210 subcloned cell exclusively, targetting a tumour-associated antigen that did not appear to be modified in the DTIC-treated subclones. A third antigen was demonstrated in the parental and DTIC treated D subclone. On the basis of these results it was postulated that there was at least one common DTIC-inducible antigen specific and reproducible within an identical cell population. Moreover, DTIC treatment did not modify histocompatibility antigens or TAA pre-existing in L1210 cells. The findings discussed here provide new information about permanent xenogenization of tumour cells, which might be exploited for experimental chemo-immunotherapy of cancer

Step by step capping and strain state of GaN/AlN quantum dots studied by grazing incidence diffraction anomalous fine structure

The investigation of small size embedded nanostructures, by a combination of complementary anomalous diffraction techniques, is reported. GaN Quantum Dots (QDs), grown by molecular beam epitaxy in a modified Stranski-Krastanow mode, are studied in terms of strain and local environment, as a function of the AlN cap layer thickness, by means of grazing incidence anomalous diffraction. That is, the X-ray photons energy is tuned across the Ga absorption K-edge which makes diffraction chemically selective. Measurement of \textit{hkl}-scans, close to the AlN (30-30) Bragg reflection, at several energies across the Ga K-edge, allows the extraction of the Ga partial structure factor, from which the in-plane strain of GaN QDs is deduced. From the fixed-Q energy-dependent diffracted intensity spectra, measured for diffraction-selected iso-strain regions corresponding to the average in-plane strain state of the QDs, quantitative information regarding composition and the out-of-plane strain has been obtained. We recover the in-plane and out-of-plane strains in the dots. The comparison to the biaxial elastic strain in a pseudomorphic layer indicates a tendency to an over-strained regime.Comment: submitted to PR

BAG3 localizes in axonal structures during neuronal differentiation and is expressed in cellular processes of migrating cells in mouse cerebral cortex

BAG3 protein belongs to the family of co-chaperones involved in protein quality control and in the clearance of misfolded proteins [1]. Few studies have addressed BAG3 distribution and function in the central nervous system (CNS) and little is known about the cellular localization of BAG3 during neuronal differentiation in vitro and migration in vivo. Therefore we analysed by immunofluorescence microscopy the cellular distribution of BAG3 in the PC12 cell model treated or not with NGF and in developing and adult cortex of mice brain. Our results shows that BAG3 localizes mainly in vesicle structures of the neuritic domain during cell differentiation, while in undifferentiated cells it appears confined to the cytoplasm near the nuclear membrane. These observations were corroborated by transmission electron microscopy (TEM) which revealed that in NGF-differentiated PC12 cells, BAG3 localizes into electron-dense vesicles clustered along the axon and showing the typical aspect of the large dense core vesicles (LDCVs). Interestingly, the change of BAG3 localization during neuronal differentiation was associated only to a slight increase in the total BAG3 immunoreactivity as shown by western blot analysis. In order to provide further insights on the role of BAG3 in neuronal differentiation and migration, we also analysed BAG3 localization in mice developing and adult cerebral cortex. In mouse developing cortex, BAG3 appeared to be intensely expressed in cellular processes of migrating cells, while in adult brain a low expression was detected in neuronal cell bodies and glial cells. In conclusion, our findings suggest that the presence and differential expression of BAG3 might be required for the correct development of the nervous system as well as for the maintenance of protein homeostasis

The endocannabinoid anandamide inhibits colon cancer cell growth by modulating different survival and proliferating pathways

The Endocannabinoid System (ECS) comprising the CB1 and CB2 receptors and their endogenous ligands is a central signalling system regulating food intake and energy balance. It is also present in peripheral tissues where it is involved in cell proliferation and survival. It has been shown that in colon cancer cells, the CB1 receptor antagonist SR171416 reduces colon cancer cell growth by acting as an inverse agonist rather than an antagonist [1]. Starting from this observation and from evidence indicating that some biological responses to cannabinoids depend on estrogen levels and some selective estrogen receptor modulators can bind the CB1 receptor [2], we aimed to study the effects of the CB1 receptor ligand anandamide (AEA) on colon cancer cell proliferation and its ability to modulate some survival and proliferating pathways including Akt, MAPK/ERK and estrogen receptor (ER) b signalling which is the predominant ER pathway in colonic epithelium. We used an AEA-analogue and a selective inhibitor of fatty acid amide hydrolase (FAAH) that enhances intracellular levels of AEA and studied proliferation and cell cycle progression on human adenocarcinoma cells DLD1 and SW620. Our results showed that increased levels of AEA significantly reduced cell proliferation in both cell lines at 24 and 48 h also inducing an S phase cell cycle accumulation. The AEA-induced inhibition of cell growth was mediated by a reduced expression of phoshoAkt and phosphoERK and, at the same time, by an induction of ERβ expression. These data suggest that AEA can reduces colon cancer cell proliferation by interfering with different signalling pathways

Loss and revival of phase coherence in a Bose-Einstein condensate moving through an optical lattice

We investigate the phase coherence of a trapped Bose-Einstein condensate that undergoes a dynamical superfluid-insulator transition in the presence of a one-dimensional optical lattice. We study the evolution of the condensate after a sudden displacement of the harmonic trapping potential by solving the Gross-Pitaevskii equation, and comparing the results with the prediction of two effective 1D models. We show that, owing to the 3D nature of the system, the breakdown of the superfluid current above a critical displacement is not associated to a sharp transition, but there exists a range of displacements for which the condensate can recover a certain degree of coherence. We also discuss the implications on the interference pattern after the ballistic expansion as measured in recent experiments at LENS.Comment: 7 pages, 9 figure

Analysis of strain and stacking faults in single nanowires using Bragg coherent diffraction imaging

Coherent diffraction imaging (CDI) on Bragg reflections is a promising technique for the study of three-dimensional (3D) composition and strain fields in nanostructures, which can be recovered directly from the coherent diffraction data recorded on single objects. In this article we report results obtained for single homogeneous and heterogeneous nanowires with a diameter smaller than 100 nm, for which we used CDI to retrieve information about deformation and faults existing in these wires. The article also discusses the influence of stacking faults, which can create artefacts during the reconstruction of the nanowire shape and deformation.Comment: 18 pages, 6 figures Submitted to New Journal of Physic

No effect of repeated post-resistance exercise cold or hot water immersion on in-season body composition and performance responses in academy rugby players : A randomised controlled cross-over design

Purpose Following resistance exercise, uncertainty exists as to whether the regular application of cold water immersion attenuates lean muscle mass increases in athletes. The effects of repeated post-resistance exercise cold versus hot water immersion on body composition and neuromuscular jump performance responses in athletes were investigated. Methods Male, academy Super Rugby players (n = 18, 19.9 ± 1.5 y, 1.85 ± 0.06 m, 98.3 ± 10.7 kg) participated in a 12-week (4-week × 3-intervention, i.e., control [CON], cold [CWI] or hot [HWI] water immersion) resistance exercise programme, utilising a randomised cross-over pre–post-design. Body composition measures were collected using dual-energy X-ray absorptiometry prior to commencement and every fourth week thereafter. Neuromuscular squat (SJ) and counter-movement jump (CMJ) performance were measured weekly. Linear mixed-effects models were used to analyse main (treatment, time) and interaction effects. Results There were no changes in lean (p = 0.960) nor fat mass (p = 0.801) between interventions. CON (p = 0.004) and CWI (p = 0.003) increased (g = 0.08–0.19) SJ height, compared to HWI. There were no changes in CMJ height (p = 0.482) between interventions. Conclusion Repeated post-resistance exercise whole-body CWI or HWI does not attenuate (nor promote) increases in lean muscle mass in athletes. Post-resistance exercise CON or CWI results in trivial increases in SJ height, compared to HWI. During an in-season competition phase, our data support the continued use of post-resistance exercise whole-body CWI by athletes as a recovery strategy which does not attenuate body composition increases in lean muscle mass, while promoting trivial increases in neuromuscular concentric-only squat jump performance

No effect of repeated post-resistance exercise cold or hot water immersion on in-season body composition and performance responses in academy rugby players: A randomised controlled cross-over design

Purpose: Following resistance exercise, uncertainty exists as to whether the regular application of cold water immersion attenuates lean muscle mass increases in athletes. The effects of repeated post-resistance exercise cold versus hot water immersion on body composition and neuromuscular jump performance responses in athletes were investigated. Methods: Male, academy Super Rugby players (n = 18, 19.9 ± 1.5 y, 1.85 ± 0.06 m, 98.3 ± 10.7 kg) participated in a 12-week (4-week × 3-intervention, i.e., control [CON], cold [CWI] or hot [HWI] water immersion) resistance exercise programme, utilising a randomised cross-over pre–post-design. Body composition measures were collected using dual-energy X-ray absorptiometry prior to commencement and every fourth week thereafter. Neuromuscular squat (SJ) and counter-movement jump (CMJ) performance were measured weekly. Linear mixed-effects models were used to analyse main (treatment, time) and interaction effects. Results: There were no changes in lean (p = 0.960) nor fat mass (p = 0.801) between interventions. CON (p = 0.004) and CWI (p = 0.003) increased (g = 0.08–0.19) SJ height, compared to HWI. There were no changes in CMJ height (p = 0.482) between interventions. Conclusion: Repeated post-resistance exercise whole-body CWI or HWI does not attenuate (nor promote) increases in lean muscle mass in athletes. Post-resistance exercise CON or CWI results in trivial increases in SJ height, compared to HWI. During an in-season competition phase, our data support the continued use of post-resistance exercise whole-body CWI by athletes as a recovery strategy which does not attenuate body composition increases in lean muscle mass, while promoting trivial increases in neuromuscular concentric-only squat jump performance