High Level Of Statistical Significance Research Articles

Distinguishing between the metabolome and xenobiotic exposome in environmental field samples analysed by direct-infusion mass spectrometry based metabolomics and lipidomics.

Environmental metabolomics is increasingly used to investigate organismal responses to complex chemical mixtures, including waste water effluent (WWE). In parallel, increasingly sensitive analytical methods are being used in metabolomics studies, particularly mass spectrometry. This introduces a considerable, yet overlooked, challenge that high analytical sensitivity will not only improve the detection of endogenous metabolites in biological specimens but also exogenous chemicals. If these often unknown xenobiotic features are not removed from the “biological” dataset, they will bias the interpretation and could lead to incorrect conclusions about the biotic response. Here we illustrate and validate a novel workflow classifying the origin of peaks detected in biological samples as: endogenous, xenobiotics, or metabolised xenobiotics. The workflow is demonstrated using direct infusion mass spectrometry-based metabolomic analysis of testes from roach exposed to different concentrations of a complex WWE. We show that xenobiotics and their metabolic products can be detected in roach testes (including triclosan, chloroxylenol and chlorophene), and that these compounds have a disproportionately high level of statistical significance within the total (bio)chemical changes induced by the WWE. Overall we have demonstrated that this workflow extracts more information from an environmental metabolomics study of complex mixture exposures than was possible previously.Electronic supplementary materialThe online version of this article (doi:10.1007/s11306-014-0693-3) contains supplementary material, which is available to authorized users.

An Empirical Model of Tax Convexity and Self-Employment

Do progressive marginal income tax rates discourage self-employment? We assume risk neutrality to construct an implicit surtax on stochastic income relative to steady income, arising from a convex tax schedule. It is computed as part of a structural probit model with earnings equations and a tax simulator. The tax convexity variable and the net-of-tax income difference between self- and paid employment have the predicted signs and high levels of statistical significance for the probability of self-employment. A simulated flat tax reform suggests the tax effects are small.

OGLE-2012-BLG-0455/MOA-2012-BLG-206: MICROLENSING EVENT WITH AMBIGUITY IN PLANETARY INTERPRETATIONS CAUSED BY INCOMPLETE COVERAGE OF PLANETARY SIGNAL

Characterizing a microlensing planet is done from modeling an observed lensing light curve. In this process, it is often confronted that solutions of different lensing parameters result in similar light curves, causing difficulties in uniquely interpreting the lens system, and thus understanding the causes of different types of degeneracy is important. In this work, we show that incomplete coverage of a planetary perturbation can result in degenerate solutions even for events where the planetary signal is detected with a high level of statistical significance. We demonstrate the degeneracy for an actually observed event OGLE-2012-BLG-0455/MOA-2012-BLG-206. The peak of this high-magnification event $(A_{\rm max}\sim400)$ exhibits very strong deviation from a point-lens model with $\Delta\chi^{2}\gtrsim4000$ for data sets with a total number of measurement 6963. From detailed modeling of the light curve, we find that the deviation can be explained by four distinct solutions, i.e., two very different sets of solutions, each with a two-fold degeneracy. While the two-fold (so-called "close/wide") degeneracy is well-understood, the degeneracy between the radically different solutions is not previously known. The model light curves of this degeneracy differ substantially in the parts that were not covered by observation, indicating that the degeneracy is caused by the incomplete coverage of the perturbation. It is expected that the frequency of the degeneracy introduced in this work will be greatly reduced with the improvement of the current lensing survey and follow-up experiments and the advent of new surveys.

The Decimal Expansion of π Is Not Statistically Random

This paper pursues the question whether the decimal expansion of π behaves as though it were the realization of a sequence of mutually independent, identically distributed random variables with uniform distribution on {0, 1, … , 9}. So far, no deviation from reasonable statistical norms has been found. We introduce an extended runs test of symbolic dynamics that π fails at a high level of statistical significance.

The Effect of Gynostemma pentaphyllum Extract on Mouse Dermal Fibroblasts.

Background. The objective of this paper is to demonstrate the effect of Gynostemma pentaphyllum extract on mouse dermal fibroblasts. Recent studies have shown that this plant may possess great antioxidant properties, which can be very beneficial in combating oxidative stress. Methods. Gynostemma pentaphyllum extract was prepared and mouse dermal fibroblasts were obtained and cultured as per our laboratory protocols. Twelve samples of cells were cultured under the same conditions and both negative and positive controls were established. Induction of oxidative stress was carried out using ultraviolet C (UVC) light. Viable cell count was carried out, using microscopy. The analysis of the overall results was processed using SPSS version 16.0. Results. Statistical analysis showed strong positive correlation between the concentration of Gynostemma pentaphyllum and the mean duration of cell viability (rs = 1), with a high level of statistical significance (P < 0.01). Likewise, strong positive correlation existed between trials of cell viability (rs = 0.988–1), with statistical significance (P < 0.01). Conclusion. Gynostemma pentaphyllum extract prolongs viability of mouse dermal fibroblasts damaged by UVC light-induced oxidative stress. The results show the potential benefits of this extract on dermal cell aging.

Could Failure of the Spring Ligament Complex Be the Driving Force behind the Development of the Adult Flatfoot Deformity?

We conducted an investigation into the relative associations of magnetic resonance imaging (MRI)–defined pathologic features of the spring ligament and/or tibialis posterior tendon with radiographic evidence of a planovalgus foot position. A total of 161 patient images (MRI and plain radiographs) obtained from the foot and ankle clinic (2008 to 2011) were retrospectively reviewed. All 161 patients (64 male and 97 female; mean age 45.9 years, range 18 to 86) were included in the analysis. Lateral weightbearing radiographs were analyzed for the talo–first metatarsal angle ≥ 5°, calcaneal pitch ≤ 20°, and talocalcaneal angle ≥ 45°. A positive finding for ≥ 1 measurements identified a radiographic planovalgus position of the foot. The radiographic deformity was analyzed against the MRI evidence of either spring ligament or tibialis posterior tendon pathologic features for significance (p < .05). Evidence of a spring ligament abnormality was strongly associated with a planovalgus foot position, reaching high levels of statistical significance in all 3 categories of radiographic deformity (odds ratio 9.2, p < .0001). Abnormalities of the tibialis posterior tendon failed to demonstrate significance, unless grade I changes were excluded, and grade II and III appearances were analyzed in isolation (odds ratio 2.9, p = .04). Although absolute causal relationships were not tested, this investigation has clearly demonstrated that MRI-defined abnormalities of the spring ligament complex are possibly of at least equal importance to tibialis posterior dysfunction for the presence of a moderate to severe radiographic planovalgus foot position.

TRIAMCINОLON IN THE TREATMENT OF THE SIMPLE BACTERIAL CYSTITIS (EXPERIMENTAL STUDY)

The problem of the bacterial cystitis treatment continues to be relevant among the urologists all over the world due to its prevalence rate and the complexity in its treatment. The goal of research: to study experimentally the influence of synthetic glucocorticoidtriamcinоlon on the inflammatory mucosa of the urinary bladder. Material. The experimental study was conducted on the outbred white reproductive rats-females. The main group of the animals (40 rats) was exposed to simulation of the inflammatory mucosa of the urinary bladder. Triamcinоlon instillations (0.3 ml) were performed on 20 rats. In the other group of rats the triamcinоlon instillation was added with intramuscular injection of antibiotics. There were two compari-son groups of rats with the simulated inflammatory mucosa of the urinary bladder. The first (20 rats) re-ceived only intramuscular antibiotics injections and the second (20 rats) received no treatment. The con-trol group of animals (10 rats) received instillations of intact 0.9% NaCl. Methods. The bladder wall ultrastructure was analyzed by the method of transmission electronic microscopy. Rresults. According to the research data, decongestion of the swelling enchasing mass was observed after 5 days of triamcinоlon instillations both with antibiotics and without it in comparison with the inflammatory process without any treatment and with the antibiotics injections only. After 10 days this result in the main group was the same as in the control group. Infiltrating cells density in the main group after 7 days was obviously lower than in the comparison groups. The triamcinоlon injections induce neovasculogenesis and fibrogenesis, improve hemorheology in the vascular plexus of the urinary bladder mucosa. The results come up to a high level of statistical significance. Summary. The experimental data prove the safety of intravesical triamcialon instillation and its therapeutic effectiveness.

The influence of precipitation intensity growth on the urban drainage systems designing

For 50 years of long observation period (1960–2009), on a high level of statistical significance (95 %), a decreasing trend of annual precipitation amounts and an increasing trend of the number of rainy days during the year (64 %) were found. For the seasonal changes (V–X), similarly, there was found a statistically significant (94 %) decreasing precipitation amount trend and an increasing trend of the number of rainy days (50 %). As far as the intensity of maximum precipitation is concerned, a very statistically significant increasing trend (95 %) was found. Taking as the basis, the model for a trend, defined for the period of 1960–2009, the increase of weighted average interval values of maximum precipitation amounts (h ≥ 0.75 t0.5) in the year 2059 was estimated to be about 26 %, in comparison with the starting year 1960. An increasing trend of maximum precipitation frequency in Wroclaw was also proved. To a safe sewerage systems designing in Wroclaw according to current standards (EN 752 2008; DWA-A118 2006), the precipitation frequency to the simulations of excessive accumulation occurrences to the land level should be changed.

Clinical Efficacy of a West African Sorghum bicolor-Based Traditional Herbal Preparation Jobelyn Shows Increased Hemoglobin and CD4+ T-Lymphocyte Counts in HIV-Positive Patients

The purpose of this study was to evaluate a traditional herbal preparation, Jobelyn,® for its effects on anemia and CD4+ T-cell counts in human immunodeficiency virus-positive (HIV+) patients in Nigeria. An open-label pilot study involving 10 confirmed (HIV+) patients who were not receiving antiretroviral therapy (ARVT) was performed, in which the patients consumed Jobelyn for 8 weeks, at a dose of 500 mg twice daily. The pilot study was followed by a controlled trial involving 51 patients, all confirmed HIV+, where the patients with CD4+ T-cell counts below 350 cells/μL were receiving ARVT. The eight patients with baseline CD4+ T-cell counts above 350 cells/μL received Jobelyn. The remaining patients who all received ARVT were randomized to ARVT alone versus ARVT+Jobelyn for 12 weeks. Patients receiving ARVT showed a statistically significant improvement in their CD4+ T-cell counts across the 12-week study period (p<0.01). Patients receiving ARVT+Jobelyn showed a faster improvement, reaching a high level of statistical significance compared to baseline already at 6 weeks (p<0.001), and remained highly significant at 12 weeks (p<0.001). This is the first controlled study conducted to evaluate efficacy of Jobelyn on immune status in HIV+ patients. The data suggest that consumption of Jobelyn contributed to improved hemoglobin levels and increased CD4+ T-cell counts in Nigerian HIV+ patients. Further studies are needed to examine similar effects in other populations, and to elaborate on the underlying mechanisms, specifically, whether the consumption of Jobelyn supported multiple aspects of bone marrow function.

Experimental Study on the Influence of Selected Process Variables on the Separation of a Fine Particle Suspension with a Pilot Scale Decanter Centrifuge

Decanter centrifuges are used widely in the chemical and process industries for dewatering and classification of solid-liquid suspensions. The most important applications of this class of centrifuges are found in wastewater sludge treatment and in pigment production. The objective of this study was to investigate the operation of a pilot scale decanter centrifuge in a challenging dewatering application. Dewatering tests were performed using fine-particle slurries consisting of water and various concentrations of kaolin. In addition to the solid concentration of the feed, the feed rate of the suspension and the differential speed between the bowl and the conveyer screw were also chosen as variables. The experimental conditions were selected according to a factorial test design and the responses monitored included the production capacity (productivity) of the decanter, the solid contents of the cake and the centrate, as well as the time that was required for the stabilization of the test unit. The results obtained clearly showed that the studied variables have a significant influence on the performance of the dewatering process. The variables were also able to explain the dewatering results at a high level of statistical significance. The repeatability of the experiments was, in most cases, good: On average, the relative standard deviations for the productivity and the solid contents of the cake were 6.0% and 0.5%. It was also apparent that random variations in the feed conditions may have a remarkable and long-lasting impact on the operation of the centrifuge.

Survival During Long-Term Starvation: Global Proteomics Analysis ofGeobacter sulfurreducensunder Prolonged Electron-Acceptor Limitation

The bioavailability of terminal electron acceptors (TEAs) and other substrates affects the efficiency of subsurface bioremediation. While it is often argued that microorganisms exist under "feast or famine", in the laboratory most organisms are studied under "feast" conditions, whereas they typically encounter "famine" in nature. The work described here aims to understand the survival strategies of the anaerobe Geobacter sulfurreduces under TEA-starvation conditions. Cultures were starved for TEA and at various times sampled to perform global comparative proteomic analysis using iTRAQ to obtain insight into the dynamics of change in proteins/enzymes expression associated with change in nutrient availability/environmental stress. Proteins varying in abundance with a high level of statistical significance (p < 0.05) were identified to understand how cells change from midlog to (i) stationary phase and (ii) conditions of prolonged starvation (survival phase). The most highly represented and significantly up-regulated proteins in the survival phase cells are involved in energy metabolism, cell envelope, and transport and binding functional categories. The majority of the proteins were predicted to be localized in the cell membranes. These results document that changes in the outer and cytoplasmic membranes are needed for survival of Geobacter under starvation conditions. The cell shuts down anabolic processes and becomes poised, through changes in its membrane proteins, to sense nutrients in the environment, to transport nutrients into the cell, and to detect or utilize TEAs that are encountered. Under TEA-limiting conditions, the cells turned from translucent white to red in color, indicating higher heme content. The increase in heme content supported proteomics results showing an increase in the number of cytochromes involved in membrane electron transport during the survival phase. The cell is also highly reduced with minimal change in energy charge (ATP to total adenine nucleotide ratio). Nonetheless, these proteomic and biochemical results indicate that even under TEA starvation cells remain poised for bioremediation.

Isolation of Salmonella Species from Milk and Locally Processed Milk Products Traded for Human Consumption and Associated Risk Factors in Kanam, Plateau State, Nigeria

This study was conducted to determine the prevalence of Salmonella species in milk and locally processed milk products traded for human consumption and assess the risk factors associated with Salmonella milk contamination in the study area. The study utilized microbiological culture and isolation as well as questionnaire analysis. A total of 600 samples were studied, 200 each for fresh milk (madara), full creamed milk (kindirmo) and skimmed milk (nono). The study revealed an overall prevalence of 8.7% (52/600). About 0.2% (1/600), 3.0% (18/600), 1.0% (6/600), 2.0% (12/600) and 2.5% (15/600) of the overall prevalence were recorded in Dengi, Gargah, Kanam, Gagdi and Gidgid districts of the Local Government Area (LGA) respectively. This revealed a high level of statistical significance (P<0.05). Prevalence rates in relation to milk type were 6.4% (38/600), 1.5% (9/600) and 0.8% (5/600) for fresh milk, full creamed milk and skimmed milk respectively. This showed a high level of statistical significance (P<0.05). Based on sources of water used for milk processing, prevalence rates were 6.8% (41/600), 1.7% (10/600) and 0.2% (1/600) for stream water, well water and borehole water respectively. These differences were highly significant statistically (P<0.05). Risk factors analysis revealed that 31.3% (188/600) of the respondents were not aware of salmonellosis and 82.2% (493/600) were not aware of the risk of acquiring Salmonella via milk consumption. There were high association between the prevalence of Salmonella in milk and the risk of sucking milk directly from the udder of cows (P<0.00001, OR = 8.7448), the use of stream water in processing milk (P=0.0001, OR = 3.6733) and failure to wash the udder of cows before milking (P=0.0041, OR = 0.2072). This study has revealed the presence of Salmonella species in milk traded for human consumption and the risk factors associated with their contamination in Kanam Local Government Area of Plateau State, Nigeria.

Chlorocarbon and Alcohol Vapor Discrimination by Electropolymerized Ultrathin Chromophore Films

Metalloporphyrin containing thin film colorimetric sensors for volatile organic compounds (VOCs) have been synthesized and characterized. Electropolymerization has been employed to synthesize robust poly-tetrakis(4-aminophenyl)porphyrin films supported on indium tin oxide (ITO) electrodes. This fabrication method afforded fine control over film thickness, yielding rapid and reproducible responses to analytes. Several metalloporphyrins were studied for their sensory response based upon the affinity of particular transition metals for organic analytes. The sensors are capable of distinguishing between several alcohol and chlorocarbon vapors at a high level of statistical significance due to a modulation of film visible absorbance upon exposure to VOC vapors.

Improving fine copper and gold flotation recovery: a plant evaluation

A statistical ‘randomised block design’ full plant trial of magnetic conditioning of flotation feed was undertaken at Rio Tinto’s Northparkes Mine in New South Wales. Magnetic conditioning of flotation feed has been shown to improve the flotation of <38 μm paramagnetic minerals consistent with selectively aggregating these paramagnetic minerals. The process was evaluated using shift composite samples that were analysed for copper and gold. Because the process targets <38 μm minerals, all samples were sized and the size-by-size recoveries were calculated for each sample. The size-by-size analysis targeted the effect on fine mineral, reduced the plant noise and shortened the test period required to get statistically significant results. An increase in gold and copper recovery was found in the <20 μm fraction to a high level of statistical significance. For the >20 and <38 μm size range, the copper recovery increased to a high level of significance, whereas the increase in gold recovery in this fraction was to a lower statistical significance. There was no statistical improvement in the >38 μm fraction for either metal. Approximately half the copper and gold losses at Northparkes are in the <20 μm size fraction. While the sulphide copper minerals chalcopyrite and bornite are known to be paramagnetic; gold is not paramagnetic. Gold’s response to magnetic conditioning, however, is consistent with a number of literature references where, depending on the gold’s mineralogical disposition, gold has been shown to respond to magnetic treatment.

Temporal Trend of Overall Survival in Patients with Advanced Non-small Cell Lung Cancer Given First-Line Cytotoxic Treatments

To the Editor, In elderly patients with advanced non-small cell lung cancer, first-line treatments are frequently based on either doublet or single third-generation cytotoxic agents. The results of the meta-analysis by Qi et al. [1] indicated that doublet therapy was superior to a single third-generation agent, but the statistical significance of this difference was borderline (end point: overall survival [OS]; hazard ratio = 0.84; 95 % confidence interval: 0.71–1; P = 0.053; data from 11 trials). We reanalyzed the data of median OS from these 11 trials for a total of 22 patient cohorts corresponding to 2,616 patients. Using standard meta-regression techniques [2–5], we investigated whether these values of median OS showed any temporal trend from 2000 to 2011. Figure 1 illustrates the results of our analysis. According to the regression line, the values of median OS varied from 5.2 months in 2000 to 11.4 months in 2011. More importantly, the annual improvement (0.56 months; 95 % confidence interval: 0.27–0.85 months) was clinically relevant and showed a high level of statistical significance (P \0.001). We are aware that one limitation of our analysis is that we did not account for the randomized design of the trials. Anyhow, the statistical impact of this temporal trend (P \ 0.001) seems to be greater than that resulting from the comparison of doublet therapy vs. single-agent (P = 0.053 according to Qi et al. [1]).

Chromatographic lipophilicity determination using large volume injections of the solvents non-miscible with the mobile phase

A new perspective in the lipophilicity evaluation through RP-HPLC is permitted by analysis of the retention factor (k) obtained by injecting large volumes of test samples prepared in solvents immiscible with mobile phase. The experiment is carried out on representative groups of compounds with increased toxicity (mycotoxins and alkaloids) and amines with important biological activity (naturally occurring monoamine compounds and related drugs), which are covering a large interval of lipophilicity. The stock solution of each compound was prepared in hexane and the used mobile phases were mixtures of methanol or acetonitrile and water, in suited volume ratio. The injected volume was between 10 and 100μL, while the used stationary phases were RP-18 and RP-8. On both reverse stationary phases the retention factors were linearly decreasing while the injection volume was increasing. In all cases, the linear models were highly statistically significant. On the basis of the obtained results new lipophilicity indices were purposed and discussed. The developed lipophilicity indices and the computationally expressed ones are correlated at a high level of statistical significance.

Changes in the diurnal periodicity of Southern California earthquakes in the neighborhood of the catalog magnitude of completeness

Dependence of the diurnal periodicity phase diagrams for Southern California earthquakes on their magnitude is studied with the Rayleigh-Schuster method. The highest statistical significance of diurnal periodicity is characteristic for the weakest non-representative earthquakes occurring in the night rather than in the daytime. The statistical significance of the earthquake diurnal periodicity decreases as the earthquake magnitude increases. Diurnal periodicity disappears in the neighborhood of the catalog magnitude of completeness. It appears again with a reasonably high level of statistical significance in the magnitude range exceeding the magnitude of completeness. However, its phase becomes opposite: strong earthquakes are more frequent in the daytime. Phase diagrams of different spatial earthquake sample groups are compared, and the night and daytime earthquake recurrence graphs are studied.

Improving the precision of quantitative bottom-up proteomics based on stable isotope-labeled proteins

Stable isotope dilution-based quantitative proteomics with intact labeled proteins as internal standards in combination with a bottom-up approach, i.e., with quantification on the peptide level, is an established method. To explore the technical precision of this approach, calmodulin-like protein 3 was prepared in non-labeled (light) and SILAC-type labeled (heavy) form by cell-free synthesis, mixed, digested with trypsin, and analyzed by UPLC-ESI-MS. In total, 16 light/heavy peptide pair ratios were determined. Pair-wise comparison of ratios of 12 peptides selected according to S/N ratios >50 revealed that the majority exhibited ratios, which were different at a high level of statistical significance (p < 0.001). HPLC-MALDI-MS ratio data confirmed this observation, thus excluding the ionization method as a source of the observed ratio differences. Variation of the digestion time from 0.25 to 4 h showed that the light/heavy ratios of most peptides decrease with time, indicating a kinetic isotope effect leading to preferred cleavage of light calmodulin-like protein 3. The subset of peptides with statistically identical ratios resulted in an average ratio with a RSD of 1.0 %. The light/heavy ratio calculated on the basis of these peptides probably provides the most accurate molar protein ratio.

Improvement of joint range of motion (ROM) and reduction of chronic pain after consumption of an ergothioneine-containing nutritional supplement

ObjectiveTo evaluate anti-inflammatory properties of a nutraceutical blend containing L-ergothioneine in concert with other anti-inflammatory and analgesic ingredients, combined with nutritional cartilage support. MethodologyTwelve human subjects were tested over a 6-week period of product consumption followed by a 6-week wash-out period, conducted at NIS Labs during late fall/early winter 2010. Range of motion (ROM) assessment of joint motility was performed using JTECH dual digital inclinometry and included flexion, extension, and rotation through the vertical weight-bearing column (neck, thorax, lumbar, hip, knees) and shoulders. Pain evaluation included questionnaires and Visual Analogues Scales regarding primary and secondary pain complaints at rest and at use. ResultsROM improvements were seen after 1week, and further improved at 6weeks (primary pain area P<0.2, secondary pain area P<0.03). Pain in primary and secondary areas at use was significantly reduced already at 1week, compared to baseline (P<0.05). Pain reduction for both primary and secondary pain areas during use reached a high level of statistical significance at 6weeks (P<0.004), and remained highly significant after the 6-week wash-out period. ConclusionPain reduction and improved ROM were observed during the 6-week consumption. Residual effects were seen 6weeks after stopping consumption of the ergothioneine supplement.

On the correlation-regression analysis of thermohaline structure of the northeastern Barents Sea waters

The results of the investigation of thermohaline structure of waters in the northeastern part of the Barents Sea are based on the data of the CTD-survey of hydrophysical testing area (for the regular grid with the resolution of 10 miles), as well as on the data of the stations of the northern part of meridional and quasi-zonal sections up to Novaya Zemlya carried out in August–September 1998 during the 14th cruise of the research vessel Akademik Sergei Vavilov of the Institute of Oceanology of the Russian Academy of Sciences. The methodology includes the analysis of average T, S-characteristics and isopycnic, correlation-regression, and factor analyses of temperature field. The vertical profiles of thermohaline properties in the testing area enable to separate at least five typical elements within the general water stratification. The representative isopycnics for the cores of water masses and transition layers are determined from the averaged T, S-diagrams. The temperature and salinity at the isopycnic surfaces in these layers fit well the linear regression model with rather high level of statistical significance, that indicates a quasi-linear nature of the state equation. The areas of the highest correlations within the water column are separated using the factor analysis of temperature field.