Correlative studies in neuro-oncology trials: should they influence treatment?

Recent molecular correlative studies accompanying clinical trials in glioma have provided strong evidence for prognostic markers and predictive factors for treatment response. However, to what extent can these markers influence the limited choice of therapeutic options? Do we further validate the markers in the next trials or move on, incorporate the markers for patient selection or stratification, aim at improving the modestly effective treatments by adding new drugs, and develop alternative therapy strategies for patients selected for their bad predictor?

Water retention and availability in soils of the State of Santa Catarina-Brazil: effect of textural classes, soil classes and lithology

The retention and availability of water in the soil vary according to the soil characteristics and determine plant growth. Thus, the aim of this study was to evaluate water retention and availability in the soils of the State of Santa Catarina, Brazil, according to the textural class, soil class and lithology. The surface and subsurface horizons of 44 profiles were sampled in different regions of the State and different cover crops to determine field capacity, permanent wilting point, available water content, particle size, and organic matter content. Water retention and availability between the horizons were compared in a mixed model, considering the textural classes, the soil classes and lithology as fixed factors and profiles as random factors. It may be concluded that water retention is greater in silty or clayey soils and that the organic matter content is higher, especially in Humic Cambisols, Nitisols and Ferralsol developed from igneous or sedimentary rocks. Water availability is greater in loam-textured soils, with high organic matter content, especially in soils of humic character. It is lower in the sandy texture class, especially in Arenosols formed from recent alluvial deposits or in gravelly soils derived from granite. The greater water availability in the surface horizons, with more organic matter than in the subsurface layers, illustrates the importance of organic matter for water retention and availability.

Synthesis, structure, and magnetic studies on self-assembled BiFeO3-CoFe2O4 nanocomposite thin films

Self-assembled (0.65)BiFeO3-(0.35)CoFe2O4 (BFO-CFO) nanostructures were deposited on SrTiO3 (001) and (111) substrates by pulsed laser deposition at various temperatures from 500 to 800°C. The crystal phases and the lattice strain for the two different substrate orientations have been determined and compared. The films grow epitaxial on both substrates but separation of the spinel and perovskite crystallites, without parasitic phases, is only obtained for growth temperatures of around 600-650°C. The BFO crystallites are out-of-plane expanded on STO(001), whereas they are almost relaxed on (111). In contrast, CFO crystallites grow out-of-plane compressed on both substrates. The asymmetric behavior of the cell parameters of CFO and BFO is discussed on the basis of the role of the epitaxial stress caused by the substrate and the spinel-perovskite interfacial stress. It is concluded that interfacial stress dominates the elastic properties of CFO crystallites and thus it may play a fundamental on the interface magnetoelectric coupling in these nanocomposites.

Design of surface forces apparatus for tribology studies combined with nonlinear optical spectroscopy

We describe the design, calibration, and performance of surface forces apparatus with the capability of illumination of the contact interface for spectroscopic investigation using optical techniques. The apparatus can be placed in the path of a Nd-YAG laser for studies of the linear response or the second harmonic and sum-frequency generation from a material confined between the two surfaces. In addition to the standard fringes of equal chromatic order technique, which we have digitized for accurate and fast analysis, the distance of separation can be measured with a fiber-optic interferometer during spectroscopic measurements (2 Å resolution and 10 ms response time). The sample approach is accomplished through application of a motor drive, piezoelectric actuator, or electromagnetic lever deflection for variable degrees of range, sensitivity, and response time. To demonstrate the operation of the instrument, the stepwise expulsion of discrete layers of octamethylcyclotetrasiloxane from the contact is shown. Lateral forces may also be studied by using piezoelectric bimorphs to induce and direct the motion of one surface.

Pulsed-field studies of the magnetization reversal in molecular nanomagnets

We report experimental studies of crystals of Mn12 molecular magnetic clusters in pulsed magnetic fields with sweep rates up to 410^3 T/s . The steps in the magnetization curve are observed at fields that are shifted with respect to the resonant field values. The shift systematically increases as the rate of the field sweep goes up. These data are consistent with the theory of the collective dipolar relaxation in molecular magnets.

Cation distribution and high field magnetization studies on SrFe12-xCrxO19

With the aim of a better understanding of both cationic distribution and magnetic properties of the uniaxial SrFe12-xCrxO19hexagonal ferrites, Mössbauer spectroscopy, neutron diffraction and high field magnetization measurements have been carried out. The Cr3+ions occupy the octahedral sites of the M structure with a preference hierarchy within them. The magnetic measurements, together with the deduced cationic distribution, indicate that some sublattices have a random spin canting around the c-axis.

Use of legal reserve areas as geochemical background in hydrosedimentology studies¹

In hydrosedimentology studies the determination of the trace element concentrations at the study site is imperative, since this background can be used to assess the enrichment of sediments with these elements. This enrichment can be the result of the natural process of geological formation or of anthropogenic activities. In the latter case, guidelines are used to indicate the concentrations at which trace elements cause ecotoxicity effects on the environment. Thus, this study used legal reserve areas in the municipality of Toledo, PR, where natural forests are maintained, with no or minimal human interference to establish background levels. The results of atomic emission spectrometry with inductively coupled argon plasma showed that the legal reserves have lower levels of trace elements than other theoretical references, but equivalent concentrations to the safety levels recommended by international guidelines. It was concluded that determining values is fundamental to recommend this background as scientific database for research in the area of hydrosedimentology of this site and also as a way of environmental management of the watershed of this municipality.

Circulating carotenoids and risk of breast cancer: pooled analysis of eight prospective studies.

Background Carotenoids, micronutrients in fruits and vegetables, may reduce breast cancer risk. Most, but not all, past studies of circulating carotenoids and breast cancer have found an inverse association with at least one carotenoid, although the specific carotenoid has varied across studies. Methods We conducted a pooled analysis of eight cohort studies comprising more than 80% of the world's published prospective data on plasma or serum carotenoids and breast cancer, including 3055 case subjects and 3956 matched control subjects. To account for laboratory differences and examine population differences across studies, we recalibrated participant carotenoid levels to a common standard by reassaying 20 plasma or serum samples from each cohort together at the same laboratory. Using conditional logistic regression, adjusting for several breast cancer risk factors, we calculated relative risks (RRs) and 95% confidence intervals (CIs) using quintiles defined among the control subjects from all studies. All P values are two-sided. Results Statistically significant inverse associations with breast cancer were observed for α-carotene (top vs bottom quintile RR = 0.87, 95% CI = 0.71 to 1.05, Ptrend = .04), β-carotene (RR = 0.83, 95% CI = 0.70 to 0.98, Ptrend = .02), lutein+zeaxanthin (RR = 0.84, 95% CI = 0.70 to 1.01, Ptrend = .05), lycopene (RR = 0.78, 95% CI = 0.62 to 0.99, Ptrend = .02), and total carotenoids (RR = 0.81, 95% CI = 0.68 to 0.96, Ptrend = .01). β-Cryptoxanthin was not statistically significantly associated with risk. Tests for heterogeneity across studies were not statistically significant. For several carotenoids, associations appeared stronger for estrogen receptor negative (ER(-)) than for ER(+) tumors (eg, β-carotene: ER(-): top vs bottom quintile RR = 0.52, 95% CI = 0.36 to 0.77, Ptrend = .001; ER(+): RR = 0.83, 95% CI = 0.66 to 1.04, Ptrend = .06; Pheterogeneity = .01). Conclusions This comprehensive prospective analysis suggests women with higher circulating levels of α-carotene, β-carotene, lutein+zeaxanthin, lycopene, and total carotenoids may be at reduced risk of breast cancer.