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Displaying publications 21 - 24 of 24 in total

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Fulltext Experimental and numerical evaluations of composite concrete-to-concrete interfacial shear strength under horizontal and normal stresses

Al-Fasih MY, Mohamad ME, Ibrahim IS, Ahmad Y, Ariffin MAM, Sarbini NN, et al.

PLoS One, 2021;16(5):e0252050.
PMID: 34015027 DOI: 10.1371/journal.pone.0252050

Effects of different surface textures on the interface shear strength, interface slip, and failure modes of the concrete-to-concrete bond are examined through finite element numerical model and experimental methods in the presence of the horizontal load with 'push-off' technique under different normal stresses. Three different surface textures are considered; smooth, indented, and transversely roughened to finish the top surfaces of the concrete bases. In the three-dimensional modeling via the ABAQUS solver, the Cohesive Zone Model (CZM) is used to simulate the interface shear failure. It is observed that the interface shear strength increases with the applied normal stress. The transversely roughened surface achieves the highest interface shear strength compared with those finished with the indented and smooth approaches. The smooth and indented surfaces are controlled by the adhesive failure mode while the transversely roughened surface is dominated by the cohesive failure mode. Also, it is observed that the CZM approach can accurately model the interface shear failure with 3-29% differences between the modeled and the experimental test findings.
Fulltext Compression Behaviour of Bio-Inspired Honeycomb Reinforced Starfish Shape Structures Using 3D Printing Technology

Saufi SASA, Zuhri MYM, Dezaki ML, Sapuan SM, Ilyas RA, As'arry A, et al.

Polymers (Basel), 2021 Dec 14;13(24).
PMID: 34960939 DOI: 10.3390/polym13244388

The bio-inspired structure (e.g., honeycomb) has been studied for its ability to absorb energy and its high strength. The cell size and wall thickness are the main elements that alter the structural ability to withstand load and pressure. Moreover, adding a secondary structure can increase the compressive strength and energy absorption (EA) capability. In this study, the bio-inspired structures are fabricated by fused deposition modelling (FDM) technology using polylactic acid (PLA) material. Samples are printed in the shape of a honeycomb structure, and a starfish shape is used as its reinforcement. Hence, this study focuses on the compression strength and EA of different cell sizes of 20 and 30 mm with different wall thicknesses ranging from 1.5 to 2.5 mm. Subsequently, the deformation and failure of the structures are determined under the compression loading. It is found that the smaller cell size with smaller wall thickness offered a crush efficiency of 69% as compared to their larger cell size with thicker wall thickness counterparts. It is observed that for a 20 mm cell size, the EA and maximum peak load increase, respectively, when the wall thickness increases. It can be concluded that the compression strength and EA capability increase gradually as the cell size and wall thickness increase.
Fulltext Indoor and outdoor residual spraying of a novel formulation of deltamethrin K-Othrine® (Polyzone) for the control of simian malaria in Sabah, Malaysia

Rohani A, Fakhriy HA, Suzilah I, Zurainee MN, Najdah WMAW, Ariffin MM, et al.

PLoS One, 2020;15(5):e0230860.
PMID: 32413033 DOI: 10.1371/journal.pone.0230860

Since 2000, human malaria cases in Malaysia were rapidly reduced with the use of insecticides in Indoor Residual Spray (IRS) and Long-Lasting Insecticide Net (LLIN). Unfortunately, monkey malaria in humans has shown an increase especially in Sabah and Sarawak. The insecticide currently used in IRS is deltamethrin K-Othrine® WG 250 wettable granule, targeting mosquitoes that rest and feed indoor. In Sabah, the primary vector for knowlesi malaria is An. balabacensis a species known to bite outdoor. This study evaluates an alternative method, the Outdoor Residual Spray (ORS) using a novel formulation of deltamethrin K-Othrine® (PolyZone) to examine it suitability to control knowlesi malaria vector in Sabah, compared to the current method. The study was performed at seven villages in Sabah having similar type of houses (wood, bamboo and concrete). Houses were sprayed with deltamethrin K-Othrine® (PolyZone) at two different dosages, 25 mg/m2 and 30 mg/m2 and deltamethrin K-Othrine® WG 250 wettable granule at 25 mg/m2, sprayed indoor and outdoor. Residual activity on different walls was assessed using standard cone bioassay techniques. For larval surveillances, potential breeding sites were surveyed. Larvae were collected and identified, pre and post spraying. Adult survey was done using Human Landing Catch (HLC) performed outdoor and indoor. Detection of malaria parasite in adults was conducted via microscopy and molecular methods. Deltamethrin K-Othrine® (PolyZone) showed higher efficacy when sprayed outdoor. The efficacy was found varied when sprayed on different types of wall surfaces. Deltamethrin K-Othrine® (PolyZone) at 25 mg/m2 was the most effective with regards to ability to high mortality and effective knock down (KD). The vector population was reduced significantly post-spraying and reduction in breeding sites as well. The number of simian malaria infected vector, human and simian malaria transmission were also greatly reduced.
Fulltext Spinal cord injury - assessing tolerability and use of combined rehabilitation and NeuroAiD (SATURN) study - primary results of an exploratory study

Kumar R, Htwe O, Baharudin A, Rhani SA, Ibrahim K, Nanra JS, et al.

J Spinal Cord Med, 2023 Jul;46(4):682-686.
PMID: 35604343 DOI: 10.1080/10790268.2022.2067972

OBJECTIVE: MLC601/MLC901 has demonstrated neuroprotective and neuroregenerative properties that enhance neurological recovery in stroke and traumatic brain injury. We aimed to evaluate its safety and potential efficacy in patients with severe spinal cord injury.
METHODS: Patients with American Spinal Injury Association (ASIA) Impairment Scale (AIS) A and B were included in an open-label cohort study. Each received a course of MLC601/MLC901 for 6 months in addition to standard care and rehabilitation. Key endpoints were safety, AIS grade and motor scores at month 6 (M6).
RESULTS: Among 30 patients included (mean age 42.2 ± 17.6 years, 24 men), 20 patients had AIS A while 10 patients had AIS B at baseline. Ten patients experienced 14 adverse events including one serious adverse event and six deaths, none were considered treatment-related. AIS improved in 25% of AIS A and 50% of AIS B. Improvement in ASIA motor score was seen most with cervical injury (median change from baseline 26.5, IQR: 6-55). These findings appear to be better than reported rates of spontaneous recovery for SCI AIS A and B.
CONCLUSION: MLC601/MLC901 is safe and may have a role in the treatment of patients with SCI. A controlled trial is justified.