Ten Simple (Empirical) Rules for Writing Science

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Detection of cancer cells in the cerebrospinal fluid: current methods and future directions

The spread of cancer into the central nervous system is a serious problem leading to neurological symptoms and rapid mortality. The current tools available for detecting the spread of cancer into the cerebrospinal fluid (CSF) are cytology, neurologic examination, and neuroimaging. All three of these methods can be applied in concert to reach a diagnosis, but they all suffer from a lack of sensitivity, leading to delays in treatment in many cases. An overview of research tools in the field of CSF cancer detection reveals a variety of promising technologies that can be used to answer questions about the biology of metastatic cancer and to develop more powerful clinical detection methods. Methods currently under investigation include new immunocytochemistry methods and flow cytometry for the in vitro detection of cells. Additionally, polymerase chain reaction, fluorescence in situ hybridization, capillary electrophoresis with laser-induced fluorescence, and mass spectrometry using matrix-assisted laser absorption-deionization time-of-flight and surface-enhanced laser desorption/ionization time-of-flight techniques are being tested for in vitro assessment of the non-cellular biomarkers in CSF. For in vivo detection of cancer in the CSF, research techniques include certain quantum dot platforms as well as magnetic iron oxide nanoparticles. As systemic therapies for cancer improve, the CNS is becoming a more common site of disease recurrence. This increases the importance of effective detection methods in the CSF, since early intervention can maximize therapeutic benefit. Furthermore, many cell-based detection methods can be combined with therapeutic agents to serve multiple medical functions through a common targeting system

Theory and Application of Dissociative Electron Capture in Molecular Identification

The coupling of an electron monochromator (EM) to a mass spectrometer (MS) has created a new analytical technique, EM-MS, for the investigation of electrophilic compounds. This method provides a powerful tool for molecular identification of compounds contained in complex matrices, such as environmental samples. EM-MS expands the application and selectivity of traditional MS through the inclusion of a new dimension in the space of molecular characteristics--the electron resonance energy spectrum. However, before this tool can realize its full potential, it will be necessary to create a library of resonance energy scans from standards of the molecules for which EM-MS offers a practical means of detection. Here, an approach supplementing direct measurement with chemical inference and quantum scattering theory is presented to demonstrate the feasibility of directly calculating resonance energy spectra. This approach makes use of the symmetry of the transition-matrix element of the captured electron to discriminate between the spectra of isomers. As a way of validating this approach, the resonance values for twenty-five nitrated aromatic compounds were measured along with their relative abundance. Subsequently, the spectra for the isomers of nitrotoluene were shown to be consistent with the symmetry-based model. The initial success of this treatment suggests that it might be possible to predict negative ion resonances and thus create a library of EM-MS standards.Comment: 18 pages, 7 figure

Test-Retest Reliability of the Digijump Machine

Repetitive jumping has been identified as a possible exercise modality able to provide sufficient stimulus to improve bone health. However, it is necessary to establish whether repetitive jumping can elicit a consistent physiological response with the ablity to monitor work rate. The purpose of this investigation was to determine the stability reliability of the Digijump device for the commonly used laboratory measures of oxygen uptake (VO2), heart rate (HR), and rate of perceived exertion (RPE). College-aged individuals (N = 17) completed two 3-min repetitive jumping bouts on the Digijump machine (120 jumps per minute, jump height = 1.27 cm) at least seven days apart. Stability reliability was calculated using the intraclass correlation coefficient derived from 1-way ANOVA. Absolute VO2 displayed the highest test-retest reliability (0.95), while the coefficient for relative VO2 was also acceptable (0.71). The test-retest reliability coefficients for HR (0.89), and RPE (0.75) were determined to be within acceptable limits. Coefficients for all variables compared well with the stability reliability reported for other ergometers such as the Stairmaster, treadmill, and cycle. This data represent an important step in determining the validity of the Digijump machine for physiological testing

Biophysical Characterization of a Beta-Peptide Bundle: Comparison To Natural Proteins

We recently described the high-resolution X-ray structure of a helical bundle composed of eight copies of the β-peptide Zwit-1F. Like many proteins in Nature, the Zwit-1F octamer contains parallel and antiparallel helices, extensive inter-helical electrostatic interactions, and a solvent-excluded hydrophobic core. Here we explore the stability of the Zwit-1F octamer using circular dichroism (CD) spectroscopy, analytical ultracentrifugation (AU), differential scanning calorimetry (DSC), and NMR. These studies demonstrate that the thermodynamic and kinetic properties of Zwit-1F closely resemble those of α-helical bundle proteins. Together these studies should provide a model for the design of β-peptide proteins with biological functions

Noise filtering and nonparametric analysis of microarray data underscores discriminating markers of oral, prostate, lung, ovarian and breast cancer

BACKGROUND: A major goal of cancer research is to identify discrete biomarkers that specifically characterize a given malignancy. These markers are useful in diagnosis, may identify potential targets for drug development, and can aid in evaluating treatment efficacy and predicting patient outcome. Microarray technology has enabled marker discovery from human cells by permitting measurement of steady-state mRNA levels derived from thousands of genes. However many challenging and unresolved issues regarding the acquisition and analysis of microarray data remain, such as accounting for both experimental and biological noise, transcripts whose expression profiles are not normally distributed, guidelines for statistical assessment of false positive/negative rates and comparing data derived from different research groups. This study addresses these issues using Affymetrix HG-U95A and HG-U133 GeneChip data derived from different research groups. RESULTS: We present here a simple non parametric approach coupled with noise filtering to identify sets of genes differentially expressed between the normal and cancer states in oral, breast, lung, prostate and ovarian tumors. An important feature of this study is the ability to integrate data from different laboratories, improving the analytical power of the individual results. One of the most interesting findings is the down regulation of genes involved in tissue differentiation. CONCLUSIONS: This study presents the development and application of a noise model that suppresses noise, limits false positives in the results, and allows integration of results from individual studies derived from different research groups

Economics of Distillers Grains Supplementation in a Forage System with Spayed Heifers

In a two-year study, spayed heifer calves were backgrounded on cornstalks with 2 lb or 5 lb wet distillers grains with solubles supplemented daily. During the summer, heifers grazed native range and received no summer supplementation or were supplemented with modified distillers grains with solubles at 0.6% BW daily. Heifers were finished on a common regimen, and an economic scenario was applied to each phase of production and overall. Supplementing more in winter increased profit, but summer supplementation did not impact overall profitability. Numerically, heifers not supplemented during the summer were more profitable than supplemented heifers