Assessing plasma glucose and lipid levels, body weight and acute toxicity following oral administration of an aqueous ethanolic extract of Parinari curatellifolia Planch, (Chrysobalanaceae) seeds in alloxan-induced diabetes in rats

The study was aimed at evaluating the safety and hypoglycaemic effects of Parinari curatellifolia seeds used in the treatment of diabetes. The plasma glucose level and other biochemical parameters, bodyweight and liver, heart, renal and acute toxicities were assessed following oral administration of an aqueous ethanol (80%) extract of the seeds in alloxan-induced diabetes in rats. Toxicity of the extractwas evaluated in Swiss albino mice by feeding the animals with the graded doses of the extract between 1.0 to 2.0 g/kg body weight orally and observed continuously for the first 4 h and hourly fornext 24 h, then 6 hourly for 48 h (72 h, acute toxicity). Diabetes was induced in male and female Wistar rats with alloxan monohydrate (150 mg/kg) dissolved in normal saline and administered intraperitoneally (i.p). The plasma glucose levels of the induced animals were monitored with a glucometer after 72 h. The animals with plasma glucose level >300 mg/dl were classified as diabetic and were included in the study. The diabetic animals were treated with the extract and a reference drug,glibenclamide, respectively for 30 days. Their effects on plasma glucose levels and some biochemical parameters were evaluated at the end of the experiment as indices of their antidiabetic activity. Themedian acute toxicity value (LD50) of the extract was determined to be 7.27 g/Kg body weight. There was significant reduction (

Advances in research on the use of biochar in soil for remediation: a review

Purpose: Soil contamination mainly from human activities remains a major environmental problem in the contemporary world. Significant work has been undertaken to position biochar as a readily-available material useful for the management of contaminants in various environmental media notably soil. Here, we review the increasing research on the use of biochar in soil for the remediation of some organic and inorganic contaminants.  Materials and methods: Bibliometric analysis was carried out within the past 10 years to determine the increasing trend in research related to biochar in soil for contaminant remediation. Five exemplar contaminants were reviewed in both laboratory and field-based studies. These included two inorganic (i.e., As and Pb) and three organic classes (i.e., sulfamethoxazole, atrazine, and PAHs). The contaminants were selected based on bibliometric data and as representatives of their various contaminant classes. For example, As and Pb are potentially toxic elements (anionic and cationic, respectively), while sulfamethoxazole, atrazine, and PAHs represent antibiotics, herbicides, and hydrocarbons, respectively.  Results and discussion: The interaction between biochar and contaminants in soil is largely driven by biochar precursor material and pyrolysis temperature as well as some characteristics of the contaminants such as octanol-water partition coefficient (KOW) and polarity. The structural and chemical characteristics of biochar in turn determine the major sorption mechanisms and define biochar’s suitability for contaminant sorption. Based on the reviewed literature, a soil treatment plan is suggested to guide the application of biochar in various soil types (paddy soils, brownfield, and mine soils) at different pH levels (4–5.5) and contaminant concentrations ( 50 mg kg−1).  Conclusions: Research on biochar has grown over the years with significant focus on its properties, and how these affect biochar’s ability to immobilize organic and inorganic contaminants in soil. Few of these studies have been field-based. More studies with greater focus on field-based soil remediation are therefore required to fully understand the behavior of biochar under natural circumstances. Other recommendations are made aimed at stimulating future research in areas where significant knowledge gaps exist

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

The impact of biochars on sorption and biodegradation of polycyclic aromatic hydrocarbons in soils-a review

Amending polycyclic aromatic hydrocarbon (PAH)-contaminated soils with biochar may be cheaper and environmentally friendly than other forms of organic materials. This has led to numerous studies on the use of biochar to either bind or stimulate the microbial degradation of organic compounds in soils. However, very little or no attention have been paid to the fact that biochars can give simultaneous impact on PAH fate processes, such as volatilization, sorption and biodegradation. In this review, we raised and considered the following questions: How does biochar affect microbes and microbial activities in the soil? What are the effects of adding biochar on sorption of PAHs? What are the effects of adding biochar on degradation of PAHs? What are the factors that we can manipulate in the laboratory to enhance the capability of biochars to degrade PAHs? A triphasic concept of how biochar can give simultaneous impact on PAH fate processes in soils was proposed, which involves rapid PAH sorption into biochar, subsequent desorption and modification of soil physicochemical properties by biochar, which in turn stimulates microbial degradation of the desorbed PAHs. It is anticipated that biochar can give simultaneous impact on PAH fate processes in soils

Toxic and nontoxic elemental enrichment in biochar at different production temperatures

The major impediment to the use of biochar for soil amendment is the presence of toxic elements; however, it is not known how variations in production temperature affect the enrichment behaviour of toxic elements as identified by mass loss and whether the level of nontoxic elements compromises biochar quality. These goals require an understanding of the solid phase which constitutes the tar and ash fractions that harbour majority of the Cation exchange capacity (CEC) and functional groups of biochars and the possible mechanisms through which these metals interact with the solid phase. Results showed that the enrichment behaviour of individual toxic and nontoxic elements at low production temperatures of 350 and 450 °C was significantly different (p < 0.005) to that of high production temperature of 650 °C. The concentration of individual toxic elements revealed maximum enrichment of 193,957 ± 36,881 μg kg-1 and 1650 ± 203 μg kg-1 for Na and B respectively at the 450 °C. While the concentrations of individual nontoxic elements, exhibited maximum enrichment of 665,187 ± 119,715 μg kg-1, 58,335 ± 13,985 μg kg-1, 8858 ± 3574 μg kg-1 and 4907 ± 1174 μg kg-1 for K, Mg, Si and Al respectively at the 450 °C. Conversely, As was the only toxic element that exhibited maximum enrichment of 21 ± 9 μg kg-1, at the 650 °C. Total toxic elemental concentrations indicated strong relationship with percentage mass loss (r2 = 0.998, p < 0.05), which was greatest at 450 °C, but indicated strong negative relationship with percentage ash content (r2 = -0.946, p < 0.210), which was greatest at 650 °C. Therefore, the 650 °C was effective in reducing both the toxic and nontoxic elements in biochar and thus, presented a quality biochar, due to its pi electrons which can result in dual benefits such as stronger binding of inorganic and organic elements to biochar in soils

Computational and DNMR Investigation of the Isomerism and Stereodynamics of the 2,2′-Binaphthalene-1,1′-diol Scaffold

The relative stabilities of three conformational isomers of 2,2′-binaphthalene-1,1′-diol diisobutyrate and the energy barriers to rotation about the pivotal aryl–aryl bond and the two aryl–oxygen bonds were investigated by variable-temperature NMR spectroscopy in conjunction with DFT computations. The experimental and calculated data were found to be in very good agreement and provide new insights into the dynamic stereochemistry of BINOL-derived tropos ligand