In this work, we have successfully synthesized pure and Cobalt (2.5% and 5%) doped-MnO
2
nanorods via a simple hydrothermal route. The morphological, structural, optical, and antibacterial effects, ...were studied using advanced analytical techniques. The grain sizes of as-prepared nanorods, were calculated in the range of 21–26 nm. The UV–Visible absorption spectroscopy shows a broad absorption band, centered at ~ 450 nm for pure, and ~ 465 nm for cobalt-doped MnO
2
nanorods, respectively. The reduction in band gap was observed from 2.36 to 1.96 eV with the increase in the dopant concentration. The antimicrobial activities of synthesized samples were studied against gram-negative (
E. coli
and
P.aeruginosa
) bacteria and a gram-positive (
S.aureus
) bacteria. The antimicrobial studies show inhibition zones in the range of 9–16 mm for pure and cobalt-doped MnO
2
. The maximum inhibition zone (MIC) was observed for 5% Co-MnO
2
doping against
E. coli
. We believe that the synthesized nanorods can be used as antimicrobial agent, and that could be used for antibacterial drug applications.
l‐Ascorbate (l‐Asc) is often added to assays with isolated FeII‐ and 2‐oxoglutarate (2OG)‐dependent oxygenases to enhance activity. l‐Asc is proposed to be important in catalysis by some 2OG ...oxygenases in vivo. We report observations on the nonenzymatic conversion of 2OG to succinate, which is mediated by hydrogen peroxide generated by the reaction of l‐Asc and dioxygen. Slow nonenzymatic oxidation of 2OG to succinate occurs with some, but not all, other reducing agents commonly used in 2OG oxygenase assays. We intend these observations will help in the robust assignment of substrates and inhibitors for 2OG oxygenases.
Taking everything into account: In catalytic reactions by some 2OG oxygenases with prolonged reaction times or high l‐ascorbate concentrations, nonenzymatic reactions of 2‐oxoacids mediated by reactive oxygen species such as H2O2 might be relevant. Knowledge of how catalysis is affected by, say, metal ions or temperature will allow appropriate controls to be implemented in kinetic studies or inhibition assays.
Environmentally friendly and cost-effective techniques are required to reclaim land degraded during mining activities. Bioaccumulation of heavy metals (HMs) in vegetables grown on contaminated soils ...can increase human health risks. The potential effects of hardwood biochar (HWB) was assessed for chromium (Cr), zinc (Zn), copper (Cu), manganese (Mn) and lead (Pb) bioavailability in mine-contaminated soils and their subsequently bioaccumulation in crops and associated health risk. HWB was applied to chromium-manganese mine contaminated soils at the rate of 3% to investigate the efficiency of HWB for the second crop in crop rotation technique. Cilantro (Coriandrum sativum) and spinach (Spinaccia oleracea) were grown as second crop in the same pots which were already used for rice cultivation as first crop (without adding further amendments). Application of HWB decreased the concentrations of Cr, Zn, Cu, Mn, and Pb in cilantro by 25.5%, 37.1%, 42.5%, 34.3%, and 36.2%, respectively as compared to control. In spinach, the reduction in concentrations of Cr was 75.0%, Zn 24.1%, Cu 70.1%, Mn 78.0%, and Pb 50.5% as compared to control. HWB significantly (P < 0.01) reduced the HMs uptake in spinach cultivated in the amended soils as compared to the spinach in control. Bioaccumulation factor results also indicate that HWB decreased the bioaccumulation of selected HMs in cilantro and spinach, thus reducing health risks. Results of the study clearly demonstrate that the use of HWB can significantly reduce HMs in vegetables, associated health risk and improve food quality, therefore can be used as soil amendment for reclamation of mine-degraded soils.
•Mine (chromium-manganese) contaminated soils were used in these experiments.•Hardwood Biochar (HWB) was added to the contaminated soils at 3% application rate.•HWB significantly (P ≤ 0.05) reduced heavy metals uptake by cilantro and spinach.•HWB reduced ADI and HQ values for Cr, Cu, Pb, Zn and Mn.•ILTCR for Pb significantly (P ≤ 0.01) decreased (cilantro 36% and spinach 50%) by HWB.
As a result of metal mining activities in Pakistan, toxic heavy metals (HMs) such as chromium (Cr) and lead (Pb) often enter the soil ecosystem, accumulate in food crops and cause serious human ...health and environmental issues. Therefore, this study examined the efficacy of biochar for contaminated soil remediation. Poplar wood biochar (PWB) and sugarcane bagasse biochar (SCBB) were amended to mine-contaminated agricultural soil at 3% and 7% (wt/wt) application rates. Lactuca sativa (Lettuce) was cultivated in these soils in a greenhouse, and uptake of HMs (Cr and Pb) as well as biomass produced were measured. Subsequently, health risks were estimated from uptake data. When amended at 7%, both biochars significantly (P<0.01) reduced plant uptake of Cr and Pb in amended soil with significant (P<0.01) increase in biomass of lettuce as compared to the control. Risk assessment results showed that both biochars decreased the daily intake of metals (DIM) and associated health risk due to consumption of lettuce as compared to the control. The Pb human health risk index (HRI) for adults and children significantly (P<0.01) decreased with sugarcane bagasse biochar applied at 7% rate relative to other treatments (including the control). Relative to controls, the SCBB and PWB reduced Cr and Pb uptake in lettuce by 69%, 73.7%, respectively, and Pb by 57% and 47.4%, respectively. For both amendments, HRI values for Cr were within safe limits for adults and children. HRI values for Pb were not within safe limits except for the sugarcane bagasse biochar applied at 7%. Results of the study indicated that application of SCBB at 7% rate to mine impacted agricultural soil effectively increased plant biomass and reduced bioaccumulation, DIM and associated HRI of Cr and Pb as compared to other treatments and the control.
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•Biochars (poplar wood (PWB) and sugarcane bagasse (SCBB)) increased lettuce biomass.•PWB7 and SCBB7 significantly (P ≤ 0.01) reduced heavy metals uptake by lettuce.•PWB and SCBB reduced daily intake values for Cr and Pb via lettuce ingestion.•Health risk index was significantly (P ≤ 0.01) decreased by higher dose of SCBB (7%).
This paper argues that, due to their inherent strategic competition, Washington and Moscow rely on low-yield or Tactical Nuclear Weapons (TNWs) to overcome intrinsic geo-strategic uncertainties of ...international politics. It further explores the nuclear policy of the US and Russia while positing that both states are depending on the use of battlefield nuclear weapons for ensuring nuclear deterrence stability. It also maintains that Pakistan’s policy of full-spectrum deterrence and its declaration to use TNWs, when certain red lines will be crossed, is in line with the policy of above-mentioned states.
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