A Review of Some Agricultural Wastes in Nigeria for Sustainability in the Production of Structural Concrete

A review of agricultural wastes available in Nigeria that is suitable for use in concrete industry, in order to attain sustainability in structural concrete production and practice, is presented in this paper. The wastes reviewed are: Cassava Peel Ash (CPA), Empty Palm Oil Fruit Brunch Ash (EPO-FBA), Rice Husk Ash (RHA), and Saw Dust Ash (SDA). Others were Palm Kernel Shell Ash (PKSA), Groundnut Husk Ash (GHA), Corncob Ash (CA), and Egg Shell Powder (ESP). The study revealed that some agricultural wastes that have potential for use as supplementary cementing material (SCM) for cement in the production of structural concrete abounds in Nigeria. It was also revealed that the necessity of standardization of procedures for testing of such wastes so that structural performance index can be compared. In addition, there is also the need for the development of classification methods similar to that of fly ash, so that their use can be enhanced. Using these waste materials in concrete will lead to sustainability in concrete production, reduction in the use of natural non-renewable resources, innovativeness in the use of wastes, and the development of small-scale industries

Posteroanterior Cervical Transcutaneous Spinal Cord Stimulation: Interactions with Cortical and Peripheral Nerve Stimulation

Transcutaneous spinal cord stimulation (TSCS) has demonstrated potential to beneficially modulate spinal cord motor and autonomic circuitry. We are interested in pairing cervical TSCS with other forms of nervous system stimulation to enhance synaptic plasticity in circuits serving hand function. We use a novel configuration for cervical TSCS in which the anode is placed anteriorly over ~C4–C5 and the cathode posteriorly over ~T2–T4. We measured the effects of single pulses of TSCS paired with single pulses of motor cortex or median nerve stimulation timed to arrive at the cervical spinal cord at varying intervals. In 13 participants with and 15 participants without chronic cervical spinal cord injury, we observed that subthreshold TSCS facilitates hand muscle responses to motor cortex stimulation, with a tendency toward greater facilitation when TSCS is timed to arrive at cervical synapses simultaneously or up to 10 milliseconds after cortical stimulus arrival. Single pulses of subthreshold TSCS had no effect on the amplitudes of median H-reflex responses or F-wave responses. These findings support a model in which TSCS paired with appropriately timed cortical stimulation has the potential to facilitate convergent transmission between descending motor circuits, segmental afferents, and spinal motor neurons serving the hand. Studies with larger numbers of participants and repetitively paired cortical and spinal stimulation are needed

Aryl amino acetamides prevent Plasmodium falciparum ring development via targeting the lipid-transfer protein PfSTART1.

With resistance to most antimalarials increasing, it is imperative that new drugs are developed. We previously identified an aryl acetamide compound, MMV006833 (M-833), that inhibited the ring-stage development of newly invaded merozoites. Here, we select parasites resistant to M-833 and identify mutations in the START lipid transfer protein (PF3D7_0104200, PfSTART1). Introducing PfSTART1 mutations into wildtype parasites reproduces resistance to M-833 as well as to more potent analogues. PfSTART1 binding to the analogues is validated using organic solvent-based Proteome Integral Solubility Alteration (Solvent PISA) assays. Imaging of invading merozoites shows the inhibitors prevent the development of ring-stage parasites potentially by inhibiting the expansion of the encasing parasitophorous vacuole membrane. The PfSTART1-targeting compounds also block transmission to mosquitoes and with multiple stages of the parasite's lifecycle being affected, PfSTART1 represents a drug target with a new mechanism of action

Comparative Study of Durability and Microstructure Properties of Concrete made with Different Grades of Nigerian Portland Limestone Cement

It is now becoming apparent that concrete should not only be strong but must also be durable. It is also believed that understanding the microstructure of the concrete will help produce strong and durable concrete, and thus enhance innovativeness in concrete application. This paper compares the durability performance and microstructure development of concrete produced with Portland limestone cement (PLC) grades 32.5R and 42.5R. The durability investigation was accomplished through coefficient of water absorption and sorptivity measurements. The scanning electron microscopy (SEM) was used to investigate the microstructure of the concrete samples.  The results show that concrete produced with cement grade 42.5R showed higher durability potential than the ones produced with grade 32.5R using 28 days curing period. Similarly, it was also observed that concrete specimens produced with 32.5R and with water/cement ratio of 0.40 have better durability index at the later dayscuring of 90 days in comparison to grade 42.5R concrete specimens.  It can be concluded that concrete produced using grade 42.5R cement has potential for better durability performance in relation to concrete produced with 32.5