Assessment of induced rat mammary tumour response to chemotherapy using the apparent diffusion coefficient of tissue water as determined by diffusion-weighted 1H-NMR spectroscopy in vivo.

Chemosensitivity of N-methyl-N-nitrosourea-induced rat mammary tumours treated with 5-fluorouracil at a dose of 100 mg kg(-1) i.p. was assessed by using diffusion-weighted 1H-MRS to measure the average diffusion coefficient (ADC) of water in the tumour tissue. ADC measurements prior to any therapy correlated positively with necrotic fraction. Tumours with low initial ADC (< 0.95 x 10(9) m2 s(-1)) showed an increase in ADC 7 days after treatment, whereas tumours with a high initial ADC (> 1.2 x 10(9) m2 s(-1)) showed a decrease. All tumours decreased significantly in volume (P < 0.05) 2, 5 and 7 days after treatment. At day 7 post-treatment, tumours with a high pre-treatment ADC started to regrow. The initial ADC value, as well as changes after treatment predict tumour chemosensitivity, which could be clinically relevant

Many worlds in one

A generic prediction of inflation is that the thermalized region we inhabit is spatially infinite. Thus, it contains an infinite number of regions of the same size as our observable universe, which we shall denote as \O-regions. We argue that the number of possible histories which may take place inside of an \O-region, from the time of recombination up to the present time, is finite. Hence, there are an infinite number of \O-regions with identical histories up to the present, but which need not be identical in the future. Moreover, all histories which are not forbidden by conservation laws will occur in a finite fraction of all \O-regions. The ensemble of \O-regions is reminiscent of the ensemble of universes in the many-world picture of quantum mechanics. An important difference, however, is that other \O-regions are unquestionably real.Comment: 9 pages, 2 figures, comments and references adde

High-Velocity clouds in the galactic all sky survey. i. catalog

We present a catalog of high-velocity clouds (HVCs) from the Galactic All Sky Survey (GASS) of southern sky neutral hydrogen, which has 57 mK sensitivity and 1 km s-1 velocity resolution and was obtained with the Parkes Telescope. Our catalog has been derived from the stray-radiation-corrected second release of GASS. We describe the data and our method of identifying HVCs and analyze the overall properties of the GASS population. We catalog a total of 1693 HVCs at declinations <0°, including 1111 positive velocity HVCs and 582 negative velocity HVCs. Our catalog also includes 295 anomalous velocity clouds (AVCs). The cloud line-widths of our HVC population have a median FWHM of ∼19 km s-1, which is lower than that found in previous surveys. The completeness of our catalog is above 95% based on comparison with the HIPASS catalog of HVCs upon which we improve by an order of magnitude in spectral resolution. We find 758 new HVCs and AVCs with no HIPASS counterpart. The GASS catalog will shed unprecedented light on the distribution and kinematic structure of southern sky HVCs, as well as delve further into the cloud populations that make up the anomalous velocity gas of the Milky Wa

Horizontal and vertical movements of starry smooth-hound Mustelus asterias in the northeast Atlantic

Commercial landings of starry smooth-hound Mustelus asterias in northern European seas are increasing, whilst our knowledge of their ecology, behaviour and population structure remains limited. M. asterias is a widely distributed demersal shark, occupying the waters of the southern North Sea and Irish Sea in the north, to at least the southern Bay of Biscay in the south, and is seasonally abundant in UK waters. There are no species-specific management measures for the northeast Atlantic stock, and the complexity of its population structure is not yet fully understood. To address this issue, we deployed both mark-recapture and electronic tags on M. asterias to gain novel insights into its horizontal and vertical movements. Our data suggest that the habitat use of M. asterias changes on a seasonal basis, with associated changes in geographical distribution, depth utilisation and experienced temperature. We report the first direct evidence of philopatry for this species, and also provide initial evidence of sex-biased dispersal and potential metapopulation-like stock structuring either side of the UK continental shelf. Investigations of finer-scale vertical movements revealed clear diel variation in vertical activity. The illustrated patterns of seasonal space-use and behaviour will provide important information to support the stock assessment process and will help inform any future management options

H I ABSORPTION TOWARD H II REGIONS AT SMALL GALACTIC LONGITUDES

We make a comprehensive study of H I absorption toward H II regions located within |l| < 10°. Structures in the extreme inner Galaxy are traced using the longitude-velocity space distribution of this absorption. We find significant H I absorption associated with the Near and Far 3 kpc Arms, the Connecting Arm, Bania's Clump 1, and the H I Tilted Disk. We also constrain the line-of-sight distances to H II regions, by using H I absorption spectra together with the H II region velocities measured by radio recombination lines

Pre-treatment energy status of primary rat tumours as the best predictor of response to 5-fluorouracil chemotherapy: a magnetic resonance spectroscopy study in vivo

Purpose: Fluorine-19 magnetic resonance spectroscopy ( F-MRS) studies of the pharmacokinetics of the anticancer drug 5-fluorouracil (FU) in patients at several clinical centres have shown that increased tumour retention of FU is associated with patient response. The mechanism of this increased tumour retention (FU trapping) is unknown. We used a pre-clinical model to investigate whether other MRS-measurable parameters would correlate with the response to FU treatment and, thus, help elucidate the mechanism(s) involved in FU trapping. Methods: MRS spectra were obtained using a double-tuned (P-31/F-19) surface coil from 29 N-methyl-N-nitrosourea-induced primary rat rumours. P-31-MRS spectra were acquired immediately prior to and at 2.5 h post-treatment with a bolus i.p. injection of FU (100 mg/kg); F-19-MRS spectra were acquired during the intervening 2.5-h period for measurement of the tumour uptake and retention of FU and of its metabolism to the cytotoxic fluoronucleotides (FNuct). From these data, four parameters were measured: tumour pH and energy status (NTP/Pi) before treatment, total FU retention, and FU anabolism to FNuct (expressed as micromoles per gram per 2.5 h). In addition, tumour response was determined at 7 days post-treatment by measurement of the percentage of change in tumour weight and was classified according to standard oncological criteria as follows: progressive (P) for a 225% increase, remissive (R) for a greater than or equal to 50% decrease or stable (S) for values lying between these two. Results: Analysis of variance (ANOVA) for statistical assessment revealed that groups P, S and R were not distinguishable using the MRS parameters; although when S and R were combined as one group of non-progressive disease (NPD; n = 24), both the NTP/Pi ratio and the total FNuct formed were significantly greater (P = 0.03) than those observed in the P group (Iz = 5). Considering all 29 tumours, linear regression showed that there were positive significant correlations between the NTP/Pi ratio and (a) the percentage of response (P = 0.04), (b) the pre-treatment pH (P = 0.002) and (c) FU retention (P = 0.02), but not FNuct formation(P = 0.66). Unlike results reported in the clinic, the percentage of response and FU retention were neither significantly correlated (P = 0.22) nor associated when groups P and NPD were compared (P = 0.27, Fischer\u27s exact test). FNuct, however, was significantly associated with response, as was the NTP/Pi ratio (P less than or equal to 0.02). Combination of FNuct with the NTP/Pi ratio increased the significance of the association with response (P = 0.003, Fischer\u27s exact test). Conclusions: Our results indicate that in this particular model the pretreatment tumour NTP/Pi ratio was the best predictor of response to a bolus injection of FU, rather than FNuct formation or FU retention. An elevated NTP/Pi ratio could reflect a well-vascularised tumour with an improved capacity for energy-dependent FU uptake and metabolism to FNuct, suggesting that further investigation of this parameter could be an important line of research, which may aid the identification of tumours likely to be sensitive to FU chemotherapy in the clinic

Consistent histories of systems and measurements in spacetime

Traditional interpretations of quantum theory in terms of wave function collapse are particularly unappealing when considering the universe as a whole, where there is no clean separation between classical observer and quantum system and where the description is inherently relativistic. As an alternative, the consistent histories approach provides an attractive "no collapse" interpretation of quantum physics. Consistent histories can also be linked to path-integral formulations that may be readily generalized to the relativistic case. A previous paper described how, in such a relativistic spacetime path formalism, the quantum history of the universe could be considered to be an eignestate of the measurements made within it. However, two important topics were not addressed in detail there: a model of measurement processes in the context of quantum histories in spacetime and a justification for why the probabilities for each possible cosmological eigenstate should follow Born's rule. The present paper addresses these topics by showing how Zurek's concepts of einselection and envariance can be applied in the context of relativistic spacetime and quantum histories. The result is a model of systems and subsystems within the universe and their interaction with each other and their environment.Comment: RevTeX 4; 37 pages; v2 is a revision in response to reviewer comments, connecting the discussion in the paper more closely to consistent history concepts; v3 has minor editorial corrections; accepted for publication in Foundations of Physics; v4 has a couple minor typographical correction

SUPERSHELLS AS MOLECULAR CLOUD FACTORIES: PARSEC RESOLUTION OBSERVATIONS OF Hi AND (CO)-C-12(J=1-0) IN GSH 287+04-17 AND GSH 277+00+36

We present parsec-scale resolution observations of the atomic and molecular ISM in two Galactic supershells, GSH 287+04–17 and GSH 277+00+36. Hi synthesis images from the Australia Telescope Compact Array are combined with 12CO(J=1–0) data from the NANTEN telescope to reveal substantial quantities of molecular gas closely associated with both shells. These data allow us to confirm an enhanced level of molecularization over the volumes of both objects, providing the first direct observational evidence of increased molecular cloud production due to the influence of supershells. We find that the atomic shell walls are dominated by cold gas with estimated temperatures and densities of T ∼ 100 K and n0 ∼ 10 cm−3. Locally, the shells show rich substructure in both tracers, with molecular gas seen elongated along the inner edges of the atomic walls, embedded within Hi filaments and clouds, or taking the form of small CO clouds at the tips of tapering atomic ‘fingers’. We discuss these structures in the context of different formation scenarios, suggesting that molecular gas embedded within shell walls is well explained by in-situ formation from the swept up medium, whereas CO seen at the ends of fingers of Hi may trace remnants of molecular clouds that pre-date the shells. A preliminary assessment of star formation activity within the shells confirms ongoing star formation in the molecular gas of both GSH 287+04–17 and GSH 277+00+36

VIP enhances TRH-stimulated prolactin secretion of pituitary tumours Studies with 31P NMR

AbstractIntravenous thyrotrophin releasing hormone (TRH) caused a 6.5-fold increase in plasma prolactin (PRL) in rats carrying implanted pituitary tumours. Vasoactive intestinal polypeptide (VIP) had no effect, but TRH given after VIP raised TRH stimulated secretion 13-fold above basal. 31P NMR spectroscopy showed that VIP caused a decrease in high energy metabolites (depleted phosphocreatine, elevated inorganic phosphate and lowered intracellular pH). TRH alone caused a similar but smaller effect; given after VIP, it caused no detectable depletion. We suggest that the changes in high energy metabolite cencentrations reflect increased cellular energy consumption consistent with a priming process (stage 1) in PRL secretion, followed by hormone release (stage 2). VIP induces stage 1 whereas RTH induced both stages