The Mechanism for Coarse Nb-Rich Particle Formation in Steel

Fine and coarse Nb-containing particles (Nb(C,N) and NbC) can be found in steel alloyed with niobium. The fine Nb-containing particles (precipitates) are of the order of several nanometers, typically ≤ 50 nm, in diameter, while the coarse Nb-containing particles (coarse Nb-rich particles) can have lengths ranging from submicron to hundreds of microns. The mechanism for the formation of the fine niobium carbide or carbonitride precipitates is well established, and their beneficial effects on strength and toughness are well documented. On the other hand, coarse Nb-rich particles are detrimental to the performance of the steel. Despite the plethora of studies on coarse Nb-rich particles, no experimental evidence has been offered for the proposed mechanisms of their formation. In this paper, the results of detailed and comprehensive experimental work that provide a novel understanding of the mechanism of formation of coarse Nb-rich particles are presented.

     

Antihypertensive and free radical scavenging properties of enzymatic rapeseed protein hydrolysates

In this study, rapeseed protein isolate (RPI) was digested with various proteases to produce rapeseed protein hydrolysates (RPHs), which were then separated into different peptide fractions (<1, 1–3, 3–5, and 5–10 kDa) by membrane ultrafiltration. Membrane fractionation showed that peptides with sizes <3 kDa had significantly (p < 0.05) reduced surface hydrophobicity when compared to the RPHs and peptide fractions with sizes >3 kDa. In contrast, the <3 kDa peptides showed significantly (p < 0.05) higher oxygen radical scavenging ability when compared to the >3 kDa peptides and RPHs. In vitro inhibition of angiotensin I-converting enzyme (ACE) was significantly (p < 0.05) higher for the Thermolysin, Proteinase K and Alcalase RPHs when compared to the pepsin + pancreatin (PP) and Flavourzyme RPHs. The Alcalase RPH had significantly (p < 0.05) higher renin inhibition among the RPHs, while with the exception of Thermolysin, the 5–10 kDa peptide fraction had the least renin-inhibitory ability when compared to the <5 kDa peptide fractions. Oral administration (100 mg/kg body weight) of the RPHs and RPI to spontaneously hypertensive rats (SHR) showed the Alcalase RPH to be the most effective in blood pressure (BP) reduction (∼24 mm Hg) while Proteinase K RPH was the least effective (∼5 mm Hg) after 8 h. However, the PP RPH had the most prolonged effect with BP reduction of ∼20 mm Hg after 24 h of oral administration. We conclude that the strong BP-lowering ability of Alcalase and PP RPHs could be due to high resistance of the peptides to structural degradation coupled with high absorption rate within the gastrointestinal tract.     

A Review on the Molecular Mechanisms of Action of Natural Products in Preventing Bone Diseases

The drugs used for treating bone diseases (BDs), at present, elicit hazardous side effects that include certain types of cancers and strokes, hence the ongoing quest for the discovery of alternatives with little or no side effects. Natural products (NPs), mainly of plant origin, have shown compelling promise in the treatments of BDs, with little or no side effects. However, the paucity in knowledge of the mechanisms behind their activities on bone remodeling has remained a hindrance to NPs’ adoption. This review discusses the pathological development of some BDs, the NP-targeted components, and the actions exerted on bone remodeling signaling pathways (e.g., Receptor Activator of Nuclear Factor κ B-ligand (RANKL)/monocyte/macrophage colony-stimulating factor (M-CSF)/osteoprotegerin (OPG), mitogen-activated protein kinase (MAPK)s/c-Jun N-terminal kinase (JNK)/nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), Kelch-like ECH-associated protein 1 (Keap-1)/nuclear factor erythroid 2–related factor 2 (Nrf2)/Heme Oxygenase-1 (HO-1), Bone Morphogenetic Protein 2 (BMP2)-Wnt/β-catenin, PhosphatidylInositol 3-Kinase (PI3K)/protein kinase B (Akt)/Glycogen Synthase Kinase 3 Beta (GSK3β), and other signaling pathways). Although majority of the studies on the osteoprotective properties of NPs against BDs were conducted ex vivo and mostly on animals, the use of NPs for treating human BDs and the prospects for future development remain promising.     

Discovery of Novel HIV Protease Inhibitors Using Modern Computational Techniques

The human immunodeficiency virus type 1 (HIV-1) has continued to be a global concern. With the new HIV incidence, the emergence of multi-drug resistance and the untoward side effects of currently used anti-HIV drugs, there is an urgent need to discover more efficient anti-HIV drugs. Modern computational tools have played vital roles in facilitating the drug discovery process. This research focuses on a pharmacophore-based similarity search to screen 111,566,735 unique compounds in the PubChem database to discover novel HIV-1 protease inhibitors (PIs). We used an in silico approach involving a 3D-similarity search, physicochemical and ADMET evaluations, HIV protease-inhibitor prediction (IC₅₀/percent inhibition), rigid receptor–molecular docking studies, binding free energy calculations and molecular dynamics (MD) simulations. The 10 FDA-approved HIV PIs (saquinavir, lopinavir, ritonavir, amprenavir, fosamprenavir, atazanavir, nelfinavir, darunavir, tipranavir and indinavir) were used as reference. The in silico analysis revealed that fourteen out of the twenty-eight selected optimized hit molecules were within the acceptable range of all the parameters investigated. The hit molecules demonstrated significant binding affinity to the HIV protease (PR) when compared to the reference drugs. The important amino acid residues involved in hydrogen bonding and п-п stacked interactions include ASP25, GLY27, ASP29, ASP30 and ILE50. These interactions help to stabilize the optimized hit molecules in the active binding site of the HIV-1 PR (PDB ID: 2Q5K). HPS/002 and HPS/004 have been found to be most promising in terms of IC₅₀/percent inhibition (90.15%) of HIV-1 PR, in addition to their drug metabolism and safety profile. These hit candidates should be investigated further as possible HIV-1 PIs with improved efficacy and low toxicity through in vitro experiments and clinical trial investigations.     

Proximate and mineral composition of three Nigerian freshwater fishes

Three Nigerian freshwater fishes were analysed for their proximate and mineral composition. Oreochromis niloticus, Clarias lazera and Mormyrus rume are classified as being in the low-fat class. Oreochromis niloticus has the highest mineral content. ©1997 SCI     

A physico-chemical study of nigerian velvet tamarind (Dialium guineense L) fruit

The edible part (pulp) of ripe Dialium guineense fruit is sweet (total sugars 582.1 g kg^?1) but acidic (pH 3.3) and relatively poor in protein (61.3 g kg^?1) and oil (700 g kg^?1), Fairly low levels of ascorbic acid and tannin are present. The seed, however, is mildly acidic (pH 5.5), poor in oil (60.1 g kg^?1) but a fairly good source of protein (148.8 g kg^?1) and minerals.     

Metal Loadings and Alkaline Mine Drainage from Active and Abandoned Mines in the Ivo River Basin Area of Southeastern Nigeria

Discharges from 11 active and abandoned mines were investigated in the Lokpaukwu-Ishiagu mining areas of Nigeria. The discharges had very high concentrations of TDS, hardness, chloride, calcium, conductivity, turbidity, and unacceptable levels of some metals. A conservative estimate is that nearly 33 million L of untreated circumneutral-alkaline drainage and effluents find their way into the Ivo River watershed annually, including about 710,000 kg of dissolved solids and 586 kg of potentially toxic metals. These discharges exceed national (FEPA) and international (EU, WHO, and USEPA) permissible standards for domestic water use and discharge into aquatic sources, and national groundwater protection standards for permitted concentrations of toxic substances in industrial effluents. Our study also revealed that wetlands that serve as sinks for this mine drainage become sources of continuous polluted recharge to both surface and groundwater. We recommend that a task force be established to investigate the environmental operations of mining companies in Nigeria, that mine sites be closely monitored by state agencies, and that host communities receive environmental education.