702 research outputs found
Site-selective quantum correlations revealed by magnetic anisotropy in the tetramer system SeCuO3
We present the investigation of a monoclinic compound SeCuO3 using x-ray
powder diffraction, magnetization, torque and electron-spin-resonance (ESR).
Structurally based analysis suggests that SeCuO3 can be considered as a 3D
network of tetramers. The values of intra-tetramer exchange interactions are
extracted from the temperature dependence of the susceptibility and amount to
~200 K. The inter-tetramer coupling leads to the development of long-range
antiferromagnetic order at TN = 8 K. An unusual temperature dependence of the
effective g-tensors is observed, accompanied with a rotation of macroscopic
magnetic axes. We explain this unique observation as due to site-selective
quantum correlations
Targeted Doxorubicin Delivery to Brain Tumors via Minicells: Proof of Principle Using Dogs with Spontaneously Occurring Tumors as a Model
BACKGROUND: Cytotoxic chemotherapy can be very effective for the treatment of cancer but toxicity on normal tissues often limits patient tolerance and often causes long-term adverse effects. The objective of this study was to assist in the preclinical development of using modified, non-living bacterially-derived minicells to deliver the potent chemotherapeutic doxorubicin via epidermal growth factor receptor (EGFR) targeting. Specifically, this study sought to evaluate the safety and efficacy of EGFR targeted, doxorubicin loaded minicells (designated EGFRminicellsDox) to deliver doxorubicin to spontaneous brain tumors in 17 companion dogs; a comparative oncology model of human brain cancers. METHODOLOGY/PRINCIPLE FINDINGS: EGFRminicellsDox were administered weekly via intravenous injection to 17 dogs with late-stage brain cancers. Biodistribution was assessed using single-photon emission computed tomography (SPECT) and magnetic resonance imaging (MRI). Anti-tumor response was determined using MRI, and blood samples were subject to toxicology (hematology, biochemistry) and inflammatory marker analysis. Targeted, doxorubicin-loaded minicells rapidly localized to the core of brain tumors. Complete resolution or marked tumor regression (>90% reduction in tumor volume) were observed in 23.53% of the cohort, with lasting anti-tumor responses characterized by remission in three dogs for more than two years. The median overall survival was 264 days (range 49 to 973). No adverse clinical, hematological or biochemical effects were observed with repeated administration of EGFRminicellsDox (30 to 98 doses administered in 10 of the 17 dogs). CONCLUSIONS/SIGNIFICANCE: Targeted minicells loaded with doxorubicin were safely administered to dogs with late stage brain cancer and clinical activity was observed. These findings demonstrate the strong potential for clinical applications of targeted, doxorubicin-loaded minicells for the effective treatment of patients with brain cancer. On this basis, we have designed a Phase 1 clinical study of EGFR-targeted, doxorubicin-loaded minicells for effective treatment of human patients with recurrent glioblastoma
X-ray Raman scattering study of aligned polyfluorene
We present a non-resonant inelastic x-ray scattering study at the carbon
K-edge on aligned poly[9,9-bis(2-ethylhexyl)-fluorene-2,7-diyl] and show that
the x-ray Raman scattering technique can be used as a practical alternative to
x-ray absorption measurements. We demonstrate that this novel method can be
applied to studies on aligned -conjugated polymers complementing
diffraction and optical studies. Combining the experimental data and a very
recently proposed theoretical scheme we demonstrate a unique property of x-ray
Raman scattering by performing the symmetry decomposition on the density of
unoccupied electronic states into - and -type symmetry contributions.Comment: 19 pages, 8 figure
Hole depletion and localization due to disorder in insulating PrBa2Cu3O7-d: a Compton scattering study
The (mostly) insulating behaviour of PrBa2Cu3O7-d is still unexplained and
even more interesting since the occasional appearance of superconductivity in
this material. Since YBa2Cu3O7-d is nominally iso-structural and always
superconducting, we have measured the electron momentum density in these
materials. We find that they differ in a striking way, the wavefunction
coherence length in PrBa2Cu3O7-d being strongly suppressed. We conclude that Pr
on Ba-site substitution disorder is responsible for the metal-insulator
transition. Preliminary efforts at growth with a method to prevent disorder
yield 90K superconducting PrBa2Cu3O7-d crystallites.Comment: 4 pages, 3 figures, revised version submitted to PR
A clinical study of kuru patients with long incubation periods at the end of the epidemic in Papua New Guinea
Kuru is so far the principal human epidemic prion disease. While its incidence has steadily declined since the cessation of its route of transmission, endocannibalism, in Papua New Guinea in the 1950s, the arrival of variant CreutzfeldtâJakob disease (vCJD), also thought to be transmitted by dietary prion exposure, has given kuru a new global relevance. We investigated all suspected cases of kuru from July 1996 to June 2004 and identified 11 kuru patients. There were four females and seven males, with an age range of 46â63 years at the onset of disease, in marked contrast to the age and sex distribution when kuru was first investigated 50 years ago. We obtained detailed histories of residence and exposure to mortuary feasts and performed serial neurological examination and genetic studies where possible. All patients were born a significant period before the mortuary practice of transumption ceased and their estimated incubation periods in some cases exceeded 50 years. The principal clinical features of kuru in the studied patients showed the same progressive cerebellar syndrome that had been previously described. Two patients showed marked cognitive impairment well before preterminal stages, in contrast to earlier clinical descriptions. In these patients, the mean clinical duration of 17 months was longer than the overall average in kuru but similar to that previously reported for the same age group, and this may relate to the effects of both patient age and PRNP codon 129 genotype. Importantly, no evidence for lymphoreticular colonization with prions, seen uniformly in vCJD, was observed in a patient with kuru at tonsil biopsy
âHello Central, Give Me Doctor Jazzâ: Auto/Ethnographic Improvisation as Educational Event in Doctoral Supervision
Through exchanges within a doctoral supervision, the authors explore a range of dilemmas and challenges for reflexive inquiry. These include the problematic business of naming, the impossibility of objective separation of self from research, the merging of researcher subjectivities, and differences between performance and performativity. We note the educational potential in what can conventionally be considered âunprofessionalâ approaches to qualitative inquiry: neologisms, personal experience, stories, conversations, music, poetry, paintings, and film. We engage in reflexive interactions with each other and with such âdata.â This was undertaken in the spirit of jazz improvisationâan unrehearsed performanceâsomething that âhappened,â an unplanned educational event but also an agency enabled by structure
Inclusive production of charged pions in p+C collisions at 158 GeV/c beam momentum
The production of charged pions in minimum bias p+C interactions is studied
using a sample of 377000 inelastic events obtained with the NA49 detector at
the CERN SPS at 158 GeV/c beam momentum. The data cover a phase space area
ranging from 0 to 1.8 GeV/c in transverse momentum and from -0.1 to 0.5 in
Feynman x. Inclusive invariant cross sections are given on a grid of 270 bins
per charge thus offering for the first time a dense coverage of the projectile
hemisphere and of the cross-over region into the target fragmentation zone.Comment: 31 pages, 30 figures, submitted to European Journal of Physic
Search for Branons at LEP
We search, in the context of extra-dimension scenarios, for the possible
existence of brane fluctuations, called branons. Events with a single photon or
a single Z-boson and missing energy and momentum collected with the L3 detector
in e^+ e^- collisions at centre-of-mass energies sqrt{s}=189-209$ GeV are
analysed. No excess over the Standard Model expectations is found and a lower
limit at 95% confidence level of 103 GeV is derived for the mass of branons,
for a scenario with small brane tensions. Alternatively, under the assumption
of a light branon, brane tensions below 180 GeV are excluded
Does sand content in spawning substrate result in early larval emergence? Evidence from a lithophilic cyprinid fish
The spawning success of lithophilic salmonids is strongly influenced by the fine sediment content (âfinesâ) of spawning substrates, yet knowledge on the impacts of fines on the spawning of non-salmonid lithophiles remains limited, despite their ecological and socio-economic importance in European rivers. Consequently, the aim here was to use an ex-situ experiment to investigate the impact of sand content on egg survival and timing of larval emergence of the surface-spawning cyprinid European barbel Barbus barbus. Thirty incubator boxes within a recirculating system were filled with one of five experimental sediment mixtures (0 to 40 % sand by mass) that each contained 300 fertilised eggs at a depth of 50 mm. Emerged, free-swimming larvae were captured and counted daily to assess grain size effects on larval survival and emergence. Specifically, total proportion of emerged larvae, cumulative daily proportion of emerged larvae and time required to reach 50 % emergence were measured during the study. Whilst the proportion of sand in the sediments did not have a significant impact on egg-to-emergence survival (mean survival per treatment 75 % to 79 %), it significantly affected the timing of larval emergence to the water column; early emergence was detected in treatments with elevated sand content (on average, 50 % emergence after 12 - 13 days versus 19 days in the control). Similar to findings from salmonid studies, these results suggest high sand content in spawning gravels can influence timing of larval emergence and potentially cyprinid lithophilic fish survival
Search for Branons at LEP
We search, in the context of extra-dimension scenarios, for the possible
existence of brane fluctuations, called branons. Events with a single photon or
a single Z-boson and missing energy and momentum collected with the L3 detector
in e^+ e^- collisions at centre-of-mass energies sqrt{s}=189-209$ GeV are
analysed. No excess over the Standard Model expectations is found and a lower
limit at 95% confidence level of 103 GeV is derived for the mass of branons,
for a scenario with small brane tensions. Alternatively, under the assumption
of a light branon, brane tensions below 180 GeV are excluded
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