Hydrochemical Evolution of Ground and Surface Water within the Amansie and Adansi Districts of the Ashanti Region, Ghana

Source–rock deductions of major ions and saturation states of minerals in groundwater were employed to determine the origin of dissolved ions and the thermodynamic controls on the groundwater composition respectivelyin groundwater within the Amansie and Adansi Districts. Results show that, silicate weathering and ion-exchange reactions are the major processes influencing groundwater chemistry within the Districts. The main objective of this study is to characterize groundwater and delineate soil-water-rock interactions responsible for the chemical evolution of groundwater within the districts. Fifty-nine boreholes, twelve wells and two stream samples were collected for quality assessment. Results also show that groundwater within the districts is strongly to moderately acidic as, 62 % of the groundwaters has pH that range 3.6 - 6.0. Acidity in ground and surface water within the districts is attributable predominantly to natural processes than mining activities; however, the groundwaters still have the potential to neutralize acids due to the presence of silicates/aluminosilicates. The waters are fresh (EC< 500 μS/cm) with conductivity values which ranged 22.8 – 473 μS/cm, and a mean value of 172.9 μS/cm. TDS of the groundwaters ranged 14.9 – 309.8 mg/L with a mean value of 112.6 mg/L. The relative abundance of cations and anions are in the order: Ca2+ > Na+ > Mg2+ > K+ and HCO3- > Cl- > SO42-respectively. The states of saturation of the groundwaters with respect to major minerals using hydrogeochemical transport model Phreeqc for Windows suggest that, anhydrite and gypsum are subsaturated and indicates that, groundwater within the districts originates from a formation with insufficient amount of these minerals in solution or short residence time of these minerals with groundwater within the districts.Two principal hydrochemical water types; Ca-Mg-HCO3 and Na–Cl have been delineated, with Ca-Mg-SO4, Na-Mg-Ca-HCO3 and Na- Cl-SO4 as minor water types. Groundwater within the districts principally evolves from fresh Ca–Mg–HCO3 type water into Na–HCO3 type water into Ca–Mg–Cl type water into Na–Cl type water along its flow path due to ion-exchange reactions and therefore, largely characterized by recharge processes through mixing with waters of geochemically different ionic signatures

Draft genome sequence of Shewanella sp. strain CP20

© 2015 Lutz et al. Shewanella sp. CP20 is a marine bacterium that survives ingestion by Tetrahymena pyriformis and is expelled from the protozoan within membrane-bound vacuoles, where the bacterial cells show long-term survival. Here, we report the draft genome sequence of Shewanella sp. CP20 and discuss the potential mechanisms facilitating intraprotozoan survival

Decolorization of reactive red-120 by using macrofungus and microfungus

The objectives of the study are to investigate the growth of Aspergillus sp. and Pleurotus sp. and decolorization of Reactive Red – 120 in Minimal Salt Solution (MSS). The growths of fungi were measured every 3 days by using spectrophotometer at 540 nm. For decolorization, the fungi were cultured in 10 mg/L and 20 mg/L of dye concentration. Furthermore, pH of 5, 7 and 9 were used to determine the optimum pH for dye decolorization. The 10 mg/L concentration and pH 5 were chosen as optimum conditions with the maximum performance of reactive dye decolorization ranging of 60%-70%. The Aspergillus sp. was more efficient todecolourize synthetic dye Reactive Red – 120 when compared to Pleurotus sp. This study contributes to the knowledge of mycoremediation and product of mycoremediation kit that could be developed and applied in industry.Keywords: aspergillus sp.; dye decolorization; mycoremediation; pleurotus sp.; reactive red – 120; synthetic dye

Structural, optical, magnetic and electrical properties of Zn1-x Co (x) O thin films

Despite a considerable effort aiming at elucidating the nature of ferromagnetism in ZnO-based magnetic semiconductor, its origin still remains debatable. Although the observation of above room temperature ferromagnetism has been reported frequently in the literature by magnetometry measurement, so far there has been no report on correlated ferromagnetism in magnetic, optical and electrical measurements. In this paper, we investigate systematically the structural, optical, magnetic and electrical properties of Zn1-x Co (x) O:Al thin films prepared by sputtering with x ranging from 0 to 0.33. We show that correlated ferromagnetism is present only in samples with x > 0.25. In contrast, samples with x < 0.2 exhibit weak ferromagnetism only in magnetometry measurement which is absent in optical and electrical measurements. We demonstrate, by systematic electrical transport studies that carrier localization indeed occurs below 20-50 K for samples with x < 0.2; however, this does not lead to the formation of ferromagnetic phase in these samples with an electron concentration in the range of 6 x 10(19) cm(-3) 1 x 10(20) cm(-3). Detailed structural and optical transmission spectroscopy analyses revealed that the anomalous Hall effect observed in samples with x > 0.25 is due to the formation of secondary phases and Co clusters.Comment: 28 pages, 8 figure

Isostatic phase transition and instability in stiff granular materials

In this letter, structural rigidity concepts are used to understand the origin of instabilities in granular aggregates. It is shown that: a) The contact network of a noncohesive granular aggregate becomes exactly isostatic in the limit of large stiffness-to-load ratio. b) Isostaticity is responsible for the anomalously large susceptibility to perturbation of these systems, and c) The load-stress response function of granular materials is critical (power-law distributed) in the isostatic limit. Thus there is a phase transition in the limit of intinitely large stiffness, and the resulting isostatic phase is characterized by huge instability to perturbation.Comment: RevTeX, 4 pages w/eps figures [psfig]. To appear in Phys. Rev. Let

Collagen degradation by host-derived enzymes during aging

Incompletely infiltrated collagen fibrils in acid-etched dentin are susceptible to degradation. We hypothesize that degradation can occur in the absence of bacteria. Partially demineralized collagen matrices (DCMs) prepared from human dentin were stored in artificial saliva. Control specimens were stored in artificial saliva containing proteolytic enzyme inhibitors, or pure mineral oil. We retrieved them at 24 hrs, 90 and 250 days to examine the extent of degradation of DCM. In the 24-hour experimental and 90- and 250-day control specimens, we observed 5- to 6-μm-thick layers of DCM containing banded collagen fibrils. DCMs were almost completely destroyed in the 250-day experimental specimens, but not when incubated with enzyme inhibitors or mineral oil. Functional enzyme analysis of dentin powder revealed low levels of collagenolytic activity that was inhibited by protease inhibitors or 0.2% chlorhexidine. We hypothesize that collagen degradation occurred over time, via host-derived matrix metalloproteinases that are released slowly over time.published_or_final_versio

The relationship between maternal characteristics and carotid intima-media thickness using an automated ultrasound technique

Objective: To investigate CIMT and its relationship with maternal demographic characteristics in healthy pregnancy. Methods: CIMT was measured using an au. Results: CIMT showed no relationship with gestational age (rho=−0.124, p=0.335), parity (Z=−0.055, p=0.960) and MAP (rho=0.110, p=0.393). A relationship was found between CIMT and maternal age (rho=0.277, p=0.028), booking BMI (rho=0.278, p=0.027), and BMI at time of study (rho=0.287, p=0.023). CIMT ranged from 0.30-0.80mm, the 97.5th percentile was 0.63 mm. Conclusion: In healthy pregnancy, we reported CIMT was related to BMI and maternal age but not parity or gestational age

In vivo and in vitro permeability of one-step self-etch adhesives

Adhesive dentistry should effectively restore the peripheral seal of dentin after enamel removal. We hypothesize that non-rinsing, simplified, one-step self-etch adhesives are effective for minimizing dentin permeability after tooth preparation procedures. Crown preparations in vital human teeth were sealed with Adper Prompt, Xeno III, iBond, or One-Up Bond F. Epoxy resin replicas were produced from polyvinyl siloxane impressions for SEM examination. Dentin surfaces from extracted human teeth were bonded with these adhesives and connected to a fluid-transport model for permeability measurements and TEM examination. Dentinal fluid droplets were observed from adhesive surfaces in resin replicas of in vivo specimens. In vitro fluid conductance of dentin bonded with one-step self-etch adhesives was either similar to or greater than that of smear-layer-covered dentin. TEM revealed water trees within the adhesives that facilitate water movement across the polymerized, highly permeable adhesives. Both in vitro and in vivo results did not support the proposed hypothesis.published_or_final_versio