Assessment of contamination by organochlorine pesticides in Solanum lycopersicum L. and Capsicum annuum L.: A market survey in Nigeria

This study investigated the presence and levels of organochlorine pesticides (OCPs) (hexachlorobenzene (HCB), α‑, β‑, δ‑, and γ‑hexachlorohexane (HCH), dieldrin, dichloro-diphenyltrichloroethane (p,p’-DDT), dichloro-diphenyl-dichloroethylene (p,p’-DDE), dichloro-diphenyldichloroethane (p,p’-DDD) and trans-nonachlor) in Solanum lycopersicum and Capsicum annuum samples commercially sold in Nigeria. OCPs were detected in all the samples analysed using Hewlett-Packard (HP 6890) gas chromatograph equipped with electron capture detector (GC-ECD). In S. lycopersicum, the total residue concentrations of ΣHCH (0.140 mg/kg), ΣHCB (0.144 mg/kg), ΣDDT (0.572 mg/kg), Σdieldrin (0.073 mg/kg), and Σtrans-nonachlor (0.117 mg/kg) were found. In C. annuum, the total residue levels of HCH, HCB, DDT, dieldrin and trans-nonachlor measured were 7.220, 0.096, 0.275, 0.037 and 0.117 mg/kg respectively. The α‑HCH isomer was not detected in S. lycopersicum and p,p’-DDD found only in C. annuum samples. The OCPs levels were generally below the FAOs maximum residue limits except for HCH and trans-nonachlor. A pair-wise linear correlations among concentrations of OCPs in S. lycopersicum samples indicated statistically significant (P = 0.05) relations between δ‑HCH and dieldrin (r = -0.997, P = 0.047), dieldrin and HCB (r = 0.99, P = 0.043), p,p’-DDD and p,p’-DDT (r = 1.00, P = 0.006).Key words: Organochlorine pesticides, Solanum lycopersicum, Capsicum annuum, vegetables, gas chromatography

Hydrobiological constraints of trace metals in surface water, coastal sediment and water lily of Calabar River, Nigeria

Trace metals concentrations in surface water, sediment and water lily (Nymphaea lotus) samples from the banks of Calabar River, a major tributary of Cross River Estuary, Nigeria were determined. Theresults revealed average concentrations 0.017, 0.010, 37.08 and 0.025 mg/l, respectively, for As, Cd, Fe and Pb in surface water samples, which exceeded Federal Environmental Protection Agency (FEPA)maximum guideline values. Elevated levels of heavy metals (As, 1.251 mg/kg; Cd, 0.038 mg/kg; Co, 0.509 mg/kg; Cu, 3.78 mg/kg; Fe, 35.48 mg/kg; Mn, 10.72 mg/kg; Ni, 0.732 mg/kg; Pb, 1.355 mg/kg; V,0.427 mg/kg; and Zn, 8.665 mg/kg) in sediment samples indicated anthropogenic influences while, measured concentrations in N. lotus were typical of a growing plant

Source Evaluation and Trace Metal Contamination in Benthic Sediments from Equatorial Ecosystems Using Multivariate Statistical Techniques

race metals (Cd, Cr, Cu, Ni and Pb) concentrations in benthic sediments were analyzed through multi-step fractionation scheme to assess the levels and sources of contamination in estuarine, riverine and freshwater ecosystems in Niger Delta (Nigeria). The degree of contamination was assessed using the individual contamination factors (ICF) and global contamination factor (GCF). Multivariate statistical approaches including principal component analysis (PCA), cluster analysis and correlation test were employed to evaluate the interrelationships and associated sources of contamination. The spatial distribution of metal concentrations followed the pattern Pb>Cu>Cr>Cd>Ni. Ecological risk index by ICF showed significant potential mobility and bioavailability for Cu, Cu and Ni. The ICF contamination trend in the benthic sediments at all studied sites was Cu>Cr>Ni>Cd>Pb. The principal component and agglomerative clustering analyses indicate that trace metals contamination in the ecosystems was influenced by multiple pollution sources

Significant survival improvement of patients with recurrent breast cancer in the periods 2001-2008 vs. 1992-2000

<p>Abstract</p> <p>Background</p> <p>It is unclear whether individualized treatments based on biological factors have improved the prognosis of recurrent breast cancer. The purpose of this study is to evaluate the survival improvement of patients with recurrent breast cancer after the introduction of third generation aromatase inhibitors (AIs) and trastuzumab.</p> <p>Methods</p> <p>A total of 407 patients who received first diagnosis of recurrent breast cancer and treatment at National Kyushu Cancer Center between 1992 and 2008 were retrospectively evaluated. As AIs and trastuzumab were approved for clinical use in Japan in 2001, the patients were divided into two time cohorts depending on whether the cancer recurred before or after 2001. Cohort A: 170 patients who were diagnosed between 1992 and 2000. Cohort B: 237 patients who were diagnosed between 2001 and 2008. Tumor characteristics, treatments, and outcome were compared.</p> <p>Results</p> <p>Fourteen percent of cohort A and 76% of cohort B received AIs and/or trastuzumab (P < 0.001). The median overall survival (OS) times after breast cancer recurrence were 1.7 years and 4.2 years for these respective cohorts (P < 0.001). Both the time period and treatment of AIs and/or trastuzumab for recurrent disease were significant prognostic factors in multivariate analysis (cohort B vs. cohort A: HR = 0.70, P = 0.01; AIs and/or trastuzumab for recurrent disease: yes vs. no: HR = 0.46, P < 0.001). When patients were categorized into 4 subgroups by the expression of hormone receptor (HR) and HER-2 status, the median OS times of the HR-positive/HER-2-negative, HR-positive/HER-2-positive, HR-negative/HER-2-positive, and HR-negative/HER-2-negative subtypes were 2.2, 2.4, 1.6, and 1.0 years in cohort A and 4.5, 5.1, 5.0, and 1.4 years in cohort B.</p> <p>Conclusions</p> <p>The prognosis of patients with recurrent breast cancer was improved over time following the introduction of AIs and trastuzumab and the survival improvement was apparent in HR- and/or HER-2-positive tumors.</p

Systematic Evaluation of Factors Influencing ChIP-Seq Fidelity

We performed a systematic evaluation of how variations in sequencing depth and other parameters influence interpretation of Chromatin immunoprecipitation (ChIP) followed by sequencing (ChIP-seq) experiments. Using Drosophila S2 cells, we generated ChIP-seq datasets for a site-specific transcription factor (Suppressor of Hairy-wing) and a histone modification (H3K36me3). We detected a chromatin state bias, open chromatin regions yielded higher coverage, which led to false positives if not corrected and had a greater effect on detection specificity than any base-composition bias. Paired-end sequencing revealed that single-end data underestimated ChIP library complexity at high coverage. The removal of reads originating at the same base reduced false-positives while having little effect on detection sensitivity. Even at a depth of ~1 read/bp coverage of mappable genome, ~1% of the narrow peaks detected on a tiling array were missed by ChIP-seq. Evaluation of widely-used ChIP-seq analysis tools suggests that adjustments or algorithm improvements are required to handle datasets with deep coverage

Broadband Multi-wavelength Properties of M87 during the 2017 Event Horizon Telescope Campaign

Abstract: In 2017, the Event Horizon Telescope (EHT) Collaboration succeeded in capturing the first direct image of the center of the M87 galaxy. The asymmetric ring morphology and size are consistent with theoretical expectations for a weakly accreting supermassive black hole of mass ∼6.5 × 109 M ⊙. The EHTC also partnered with several international facilities in space and on the ground, to arrange an extensive, quasi-simultaneous multi-wavelength campaign. This Letter presents the results and analysis of this campaign, as well as the multi-wavelength data as a legacy data repository. We captured M87 in a historically low state, and the core flux dominates over HST-1 at high energies, making it possible to combine core flux constraints with the more spatially precise very long baseline interferometry data. We present the most complete simultaneous multi-wavelength spectrum of the active nucleus to date, and discuss the complexity and caveats of combining data from different spatial scales into one broadband spectrum. We apply two heuristic, isotropic leptonic single-zone models to provide insight into the basic source properties, but conclude that a structured jet is necessary to explain M87’s spectrum. We can exclude that the simultaneous γ-ray emission is produced via inverse Compton emission in the same region producing the EHT mm-band emission, and further conclude that the γ-rays can only be produced in the inner jets (inward of HST-1) if there are strongly particle-dominated regions. Direct synchrotron emission from accelerated protons and secondaries cannot yet be excluded