805 research outputs found
Assessment of Heavy Metals Level of River Kaduna at Kaduna Metropolis, Nigeria
River Kaduna which serves as source of water for farming, domestic and industrial uses suffers enormous pollution as a result of industrial activities and other anthropogenic sources of contamination. The study determines the concentration of some selected heavy metal of the surface waters of River Kaduna, examines the pollution status and the implications of the heavy metal pollution on human health and the environment. The water Samples were collected using Grab method along the River Kaduna at five points – Bypass, Barnawa, Down quarters, Kakuri – Makera drains and Kudendan. Six samples during the rainy season and another during the dry season. The samples were taken to the laboratory and analyzed for chromium, Arsenic, Iron, copper, Berium, Aluminium, Cadmium, Cyanide and zinc using Atomic Absorption Spectrophotometer. The results obtained from the analysis were compared with the World Health Organization (WHO) recommended standards in order to ascertain the magnitude of pollution and the quality of the water. The concentrations of the metals were observed to be higher than WHO acceptable limits. This revealed that the river have become contaminated by heavy metals discharged into the river especially from the industries and municipal wastes and may cause serious ecological and health hazards. The paper recommends that there should be proper monitoring of effluents, there is the need for mass education of people on the impact of indiscriminate waste discharge on the water quality, and a regular schedule for sampling tributary streams and the main river Kaduna should be established. Keywords: Heavy metals, Pollution, Hazard, Environment, Industrial Wastes and Effluents
Design of an Integrated Cotton Picking System for Small-Scale Indian Agriculture
India, the world's largest producer of cotton, contains more than 4 million cotton farms that are less than 5 acres. These farms are incapable of large-scale mechanization due to small farm size and irregular farm shape. A previous team developed a handheld, roller-based picking device that demonstrated increased performance over similar products. However, a significant improvement in productivity requires increasing picking speed through mechanization as well as increasing worker cotton carrying capacity. We present a system that utilizes the roller-based picking device in tandem with a compressive storage bag and an efficient carrier. Through modeling and initial testing, the system demonstrates a two times (2X) improvement in worker productivity over current methods. This paper characterizes the cotton picking process, details the modules of the integrated system, and suggests further procedural improvements for greater increases in worker productivity
Ectopic A-lattice seams destabilize microtubules
Natural microtubules typically include one A-lattice seam within an otherwise helically symmetric B-lattice tube. It is currently unclear how A-lattice seams influence microtubule dynamic instability. Here we find that including extra A-lattice seams in GMPCPP microtubules, structural analogues of the GTP caps of dynamic microtubules, destabilizes them, enhancing their median shrinkage rate by >20-fold. Dynamic microtubules nucleated by seeds containing extra A-lattice seams have growth rates similar to microtubules nucleated by B-lattice seeds, yet have increased catastrophe frequencies at both ends. Furthermore, binding B-lattice GDP microtubules to a rigor kinesin surface stabilizes them against shrinkage, whereas microtubules with extra A-lattice seams are stabilized only slightly. Our data suggest that introducing extra A-lattice seams into dynamic microtubules destabilizes them by destabilizing their GTP caps. On this basis, we propose that the single A-lattice seam of natural B-lattice MTs may act as a trigger point, and potentially a regulation point, for catastrophe
West African medicinal plants and their constituent compounds as treatments for viral infections, including SARS-CoV-2/COVID-19
Objectives: The recent emergence of the COVID-19 pandemic (caused by SARS-CoV-2) and the experience of its unprecedented alarming toll on humanity have shone a fresh spotlight on the weakness of global preparedness for pandemics, significant health inequalities, and the fragility of healthcare systems in certain regions of the world. It is imperative to identify effective drug treatments for COVID-19. Therefore, the objective of this review is to present a unique and contextualised collection of antiviral natural plants or remedies from the West African sub-region as existing or potential treatments for viral infections, including COVID-19, with emphasis on their mechanisms of action.
Evidence acquisition: Evidence was synthesised from the literature using appropriate keywords as search terms within scientific databases such as Scopus, PubMed, Web of Science and Google Scholar.
Results: While some vaccines and small-molecule drugs are now available to combat COVID-19, access to these therapeutic entities in many countries is still quite limited. In addition, significant aspects of the symptomatology, pathophysiology and long-term prognosis of the infection yet remain unknown. The existing therapeutic armamentarium, therefore, requires significant expansion. There is evidence that natural products with antiviral effects have been used in successfully managing COVID-19 symptoms and could be developed as anti-COVID-19 agents which act through host- and virus-based molecular targets.
Conclusion: Natural products could be successfully exploited for treating viral infections/diseases, including COVID-19. Strengthening natural products research capacity in developing countries is, therefore, a key strategy for reducing health inequalities, improving global health, and enhancing preparedness for future pandemics
The impact of proton LET/RBE modeling and robustness analysis on base-of-skull and pediatric craniopharyngioma proton plans relative to VMAT
Purpose: Pediatric craniopharyngioma, adult base-of-skull sarcoma and chordoma cases are all
regarded as priority candidates for proton therapy. In this study, a dosimetric comparison between
volumetric modulated arc therapy (VMAT) and intensity modulated proton therapy (IMPT) was first
performed. We then investigated the impact of physical and biological uncertainties. We assessed
whether IMPT plans remained dosimetrically superior when such uncertainty estimates were considered, especially with regards to sparing organs at risk (OARs).
Methodology: We studied 10 cases: four chondrosarcoma, two chordoma and four pediatric craniopharyngioma. VMAT and IMPT plans were created according to modality-specific protocols. For IMPT,
we considered (i) variable RBE modeling using the McNamara model for different values of (a/b)x, and
(ii) robustness analysis with ±3 mm set-up and 3.5% range uncertainties.
Results: When comparing the VMAT and IMPT plans, the dosimetric advantages of IMPT were clear:
IMPT led to reduced integral dose and, typically, improved CTV coverage given our OAR constraints.
When physical robustness analysis was performed for IMPT, some uncertainty scenarios worsened the
CTV coverage but not usually beyond that achieved by VMAT. Certain scenarios caused OAR constraints to be exceeded, particularly for the brainstem and optical chiasm. However, variable RBE modeling predicted even more substantial hotspots, especially for low values of (a/b)x. Variable RBE
modeling often prompted dose constraints to be exceeded for critical structures.
Conclusion: For base-of-skull and pediatric craniopharyngioma cases, both physical and biological
robustness analyses should be considered for IMPT: these analyses can substantially affect the sparing
of OARs and comparisons against VMAT. All proton RBE modeling is subject to high levels of uncertainty, but the clinical community should remain cognizant possible RBE effects. Careful clinical and
imaging follow-up, plus further research on end-of-range RBE mitigation strategies such as LET optimization, should be prioritized for these cohorts of proton patients
Quasar Sightline and Galaxy Evolution (QSAGE) - III. The mass-metallicity and fundamental metallicity relation of z ≈ 2.2 galaxies
We present analysis of the mass-metallicity relation (MZR) for a sample of 67 [O iii]-selected star-forming (SF) galaxies at a redshift range of z = 1.99-2.32 (zmed = 2.16) using Hubble Space Telescope Wide Field Camera 3 grism spectroscopy from the Quasar Sightline and Galaxy Evolution survey. Metallicities were determined using empirical gas-phase metallicity calibrations based on the strong emission lines [O ii]3727, 3729, [O iii]4959, 5007 and Hβ. SF galaxies were identified, and distinguished from active-galactic nuclei, via Mass-Excitation diagrams. Using z ∼0 metallicity calibrations, we observe a negative offset in the z = 2.2 MZR of ≈-0.51 dex in metallicity when compared to locally derived relationships, in agreement with previous literature analysis. A similar offset of ≈-0.46 dex in metallicity is found when using empirical metallicity calibrations that are suitable out to z ∼5, though our z = 2.2 MZR, in this case, has a shallower slope. We find agreement between our MZR and those predicted from various galaxy evolution models and simulations. Additionally, we explore the extended fundamental metallicity relation (FMR) which includes an additional dependence on star formation rate. Our results consistently support the existence of the FMR, as well as revealing an offset of 0.28 ± 0.04 dex in metallicity compared to locally derived relationships, consistent with previous studies at similar redshifts. We interpret the negative correlation with SFR at fixed mass, inferred from an FMR existing for our sample, as being caused by the efficient accretion of metal-poor gas fuelling SFR at cosmic noon
Oncogenic cooperation between TCF7-SPI1 and NRAS(G12D) requires β-catenin activity to drive T-cell acute lymphoblastic leukemia
Spi-1 Proto-Oncogene (SPI1) fusion genes are recurrently found in T-cell acute lymphoblastic leukemia (T-ALL) cases but are insufficient to drive leukemogenesis. Here we show that SPI1 fusions in combination with activating NRAS mutations drive an immature T-ALL in vivo using a conditional bone marrow transplant mouse model. Addition of the oncogenic fusion to the NRAS mutation also results in a higher leukemic stem cell frequency. Mechanistically, genetic deletion of the β-catenin binding domain within Transcription factor 7 (TCF7)-SPI1 or use of a TCF/β-catenin interaction antagonist abolishes the oncogenic activity of the fusion. Targeting the TCF7-SPI1 fusion in vivo with a doxycycline-inducible knockdown results in increased differentiation. Moreover, both pharmacological and genetic inhibition lead to down-regulation of SPI1 targets. Together, our results reveal an example where TCF7-SPI1 leukemia is vulnerable to pharmacological targeting of the TCF/β-catenin interaction
Design considerations in a sib-pair study of linkage for susceptibility loci in cancer
<p>Abstract</p> <p>Background</p> <p>Modern approaches to identifying new genes associated with disease allow very fine analysis of associaton and can be performed in population based case-control studies. However, the sibpair design is still valuable because it requires few assumptions other than acceptably high penetrance to identify genetic loci.</p> <p>Methods</p> <p>We conducted simulation studies to assess the impact of design factors on relative efficiency for a linkage study of colorectal cancer. We considered two test statistics, one comparing the mean IBD probability in affected pairs to its null value of 0.5, and one comparing the mean IBD probabilities between affected and discordant pairs. We varied numbers of parents available, numbers of affected and unaffected siblings, reconstructing the genotype of an unavailable affected sibling by a spouse and offspring, and elimination of sibships where the proband carries a mutation at another locus.</p> <p>Results</p> <p>Power and efficiency were most affected by the number of affected sibs, the number of sib pairs genotyped, and the risk attributable to linked and unlinked loci. Genotyping unaffected siblings added little power for low penetrance models, but improved validity of tests when there was genetic heterogeneity and for multipoint testing. The efficiency of the concordant-only test was nearly always better than the concordant-discordant test. Replacement of an unavailable affected sibling by a spouse and offspring recovered some linkage information, particularly if several offspring were available. In multipoint analysis, the concordant-only test was showed a small anticonservative bias at 5 cM, while the multipoint concordant-discordant test was generally the most powerful test, and was not biased away from the null at 5 cM.</p> <p>Conclusion</p> <p>Genotyping parents and unaffected siblings is useful for detecting genotyping errors and if allele frequencies are uncertain. If adequate allele frequency data are available, we suggest a single-point affecteds-only analysis for an initial scan, followed by a multipoint analysis of affected and unaffected members of all available sibships with additional markers around initial hits.</p
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