Search

In this work, reduced graphene oxide-coated zinc borotellurite doped with erbium oxide nanoparticles denoted as ZBTEr (NPs)-rGO was studied as an approach to enhance the optical properties of glass materials. Herein, a melt-quenched technique was used to prepare the ZBTEr (NPs) glasses. A simple and inexpensive spray-coated technique was employed to deposit the rGO onto the glass surfaces directly. The morphological studies of ZBTEr (NPs)-rGO glass surfaces were investigated by scanning electron microscope (SEM) and high-resolution transmission electron microscopy (HR-TEM) meanwhile, the structural investigation of ZBTEr (NPs) glasses was revealed by X-ray diffraction (XRD) and Raman analysis. The morphological analysis revealed the residual oxygen groups functionalized on ZBTEr (NPs)-rGO glass surfaces meanwhile, TEM images confirmed the presence of Er (NPs) in the glassy matrix. The glass samples showed the existence of structural disorder and amorphous nature. The absorption spectra presented the transition bands that existed from 4I15/2 ground state level to excited state levels of 2H9/2, 4F5/2, 4F7/2, 2H11/2, 4S3/2, 4F9/2, 4I11/2, and 4I9/2, respectively. Judd–Ofelt analysis was performed to obtain the intensity parameters (Ωλ), radiative transition (A), branching ratios (βR), and radiative lifetimes (tr). The radiative parameter and branching ratio values suggested the higher stimulated emission radiative at 2H11/2 → 4I15/2 transition for present glass The luminescence spectra exhibited two emission peaks centred at 539 nm and 558 nm which were assigned to 2H11/2 → 4I15/2 and 4S3/2 → 4I15/2 transitions, respectively. The optical results for ZBTEr (NPs)-rGO and ZBTEr (NPs)-uncoated were compared to determine the differences between coated and uncoated glasses. These results highlight the significant effect of rGO deposited onto tellurite-based glass and thus, this work proposed the potential coating materials for improving current fiber optics. [ABSTRACT FROM AUTHOR]

Single phase non-stoichiometric bismuth zinc niobate, Bi3Zn1.84Nb3O13.84 was prepared by a conventional solid state method. The sample was refined and fully indexed on the cubic system, space group Fd3m, Z = 4 with a = 10.5579(4) Å. Electrical characterisation was performed using an ac impedance analyser over the temperature range of 25-850 °C and frequency range of 5 Hz-3 MHz. Typical dielectric response was observed in Bi3Zn1.84Nb3O13.84 with high relative permittivity, low dielectric loss and negative temperature coefficient of capacitance, with the values of 147, 0.002 and -396 ppm/°C, at 100 kHz at ambient temperature, respectively. The material is highly resistive, with the conductivity of 10-21 ohm-1·cm-1 and a high activation energy of ~1.59 eV. [ABSTRACT FROM AUTHOR]

Graphene-based nanomaterials offer superior properties especially in optical performance. The existence of oxygen functionalized group in graphene active layers is beneficial to enhance the optical properties of current tellurite glass. In this work, two series of glasses denoted as ZBTEr (uncoated) and ZBTEr-GO (coated) were successfully prepared using melt-quenching and low-cost spray coating techniques. X-ray diffraction analysis was done on both glass series and confirmed the amorphous structural arrangement in the glass system. Morphological study was investigated by using Scanning Electron Microscopy (SEM) and revealed the distribution of graphene layers on the glass surface. The UV-Vis spectroscopy was carried out and several absorption bands were determined for both series of glasses. The computation of oxide ion polarizability and optical basicity were investigated based on Lorentz-Lorentz equation. The oxide ion polarizability and optical basicity for ZBTEr-GO (coated) glasses were found higher than ZBTEr (uncoated) glasses due to the existence of sp2 graphitic attached on the oxygenic functional groups in GO layers. The metallization criterion values for ZBTEr-GO (coated) glasses were found decreased and tend to be more metallic. Hence, the deposition of graphene layers on the tellurite glasses offer a new strategy to improve the current telecommunication devices. [ABSTRACT FROM AUTHOR]

Background: Diffusion tensor imaging (DTI) is a promising technique for the visualization of the cervical spinal cord (CSC) in vivo. It provides information about the tissue structure of axonal white matter, and it is thought to be more sensitive than other MR imaging techniques for the evaluation of damage to tracts in the spinal cord., Aim: The purpose of this study was to determine the within-participants reliability and error magnitude of measurements of DTI metrics in healthy human CSC., Methods: A total of twenty healthy controls (10 male, mean age: 33.9 ± 3.5 years, 10 females, mean age: 47.5 ± 14.4 years), with no family history of any neurological disorders or a contraindication to MRI scanning were recruited over a period of two months. Each participant was scanned twice with an MRI 3 T scanner using standard DTI sequences. Spinal Cord Toolbox (SCT) software was used for image post-processing. Data were first corrected for motion artefact, then segmented, registered to a template, and then the DTI metrics were computed. The within-participants coefficients of variation (CV%), the single and average within-participants intraclass correlation coefficients (ICC) and Bland-Altman plots for WM, VC, DC and LC fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) were determined for the cervical spinal cord (between the 2nd and 5th cervical vertebrae)., Results: DTI metrics showed poor to excellent within-participants reliability for both single and average ICC and moderate to high reproducibility for CV%, all variation dependent on the location of the ROI. The BA plots showed good within-participants agreement between the scan-rescan values., Conclusion: Results from this reliability study demonstrate that clinical trials using the DTI technique are feasible and that DTI, in particular regions of the cord is suitable for use for the monitoring of degenerative WM changes., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Objectives: Diffusion tensor imaging (DTI) techniques are being studied as a possible diagnostic and predictive tool for the evaluation of cervical spinal cord disease. This systematic review aims to evaluate the previous DTI studies that specifically investigated the repeatability and reproducibility of DTI in the cervical spinal cord., Methods and Materials: A search in the PubMed, Scopus, Web of Science and Ovid electronic databases was conducted for articles published between January 1990 and February 2022 that related to the repeatability and reproducibility of DTI in evaluating the cervical spinal cord using one of the following measurements: the intraclass correlation coefficient (ICC) and/or the coefficient of variation (CV), and/or Bland-Altman (BA) differences analysis methods. DTI studies that presented full statistical analysis of repeatability and/or reproducibility tests of the cervical spinal cord in peer-reviewed full-text publications published in journals were included. Articles that included at least one of the keywords within the titles or abstracts were identified. Additional full-text papers were found by searching the citations and reference lists of related articles. This review has followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidance. Risk of bias was evaluated with 13 criteria weighted toward methodological quality of reported studies using the QuADS assessment criteria. This assessment only included full-text articles written in English., Results: A total of 11 studies were included and assessed for different characteristics, including sample size,(3-34) re-test time interval (<1 h to >3 months), test-retest reproducibility scores and acquisition method. Six studies used ICC which ranged from poor (ICC<0.37) to excellent reproducibility (ICC 0.91-0.99). Four studies reported an overall CV lower than 40% for all DTI metrics. Three studies reported the Bland-Altman (BA) differences and reported a minimum percentage showing no strong differences between repeated measurements. Quantitative analysis was not undertaken due to heterogeneity of methods. Repeatability and reproducibility measures were generally found to be good., Conclusion: This study revealed that the application of DTI and its related measures in a clinical setting in the assessment of cervical spinal cord changes is feasible and reproducible. However, cervical spinal cord DTI suffers from some existing limitations that prevent it from being routinely used in research and clinical settings., Advances in Knowledge: DTI with its parametric maps provide broad evaluation of the tissue structure of axonal white matter and are being studied as a possible diagnostic and predictive tool for the assessment of cervical spinal cord (CSC) disease.

Microalgae are well known for their metal sorption capacities, but their potential in the remediation of hydrophobic organic compounds has received little attention in polar regions. We evaluated in the laboratory the ability of an Antarctic microalga to remediate diesel hydrocarbons and also investigated physiological changes consequent upon diesel exposure. Using a polyphasic taxonomic approach, the microalgal isolate, WCY&#95;AQ5&#95;1, originally sampled from Greenwich Island (South Shetland Islands, maritime Antarctica) was identified as Tritostichococcus sp. (OQ225631), a recently erected lineage within the redefined Stichococcus clade. Over a nine-day experimental incubation, 57.6% of diesel (~3.47 g/L) was removed via biosorption and biodegradation, demonstrating the strain's potential for phytoremediation. Fourier transform infrared spectroscopy confirmed the adsorption of oil in accordance with its hydrophobic characteristics. Overall, degradation predominated over sorption of diesel. Chromatographic analysis confirmed that the strain efficiently metabolised medium-chain length n -alkanes (C-7 to C-21), particularly n -heneicosane. Mixotrophic cultivation using diesel as the organic carbon source under a constant light regime altered the car/chl-a ratio and triggered vacuolar activities. A small number of intracellular lipid droplets were observed on the seventh day of cultivation in transmission electron microscopic imaging. This is the first confirmation of diesel remediation ability in an Antarctic green microalga.

Research has confirmed that the utilisation of Antarctic microorganisms, such as bacteria, yeasts and fungi, in the bioremediation of diesel may provide practical alternative approaches. However, to date there has been very little attention towards Antarctic microalgae as potential hydrocarbon degraders. Therefore, this study focused on the utilisation of an Antarctic microalga in the bioremediation of diesel. The studied microalgal strain was originally obtained from a freshwater ecosystem in Paradise Bay, western Antarctic Peninsula. When analysed in systems with and without aeration, this microalgal strain achieved a higher growth rate under aeration. To maintain the growth of this microalga optimally, a conventional one-factor-at a-time (OFAT) analysis was also conducted. Based on the optimized parameters, algal growth and diesel degradation performance was highest at pH 7.5 with 0.5 mg/L NaCl concentration and 0.5 g/L of NaNO 3 as a nitrogen source. This currently unidentified microalga flourished in the presence of diesel, with maximum algal cell numbers on day 7 of incubation in the presence of 1% v / v diesel. Chlorophyll a , b and carotenoid contents of the culture were greatest on day 9 of incubation. The diesel degradation achieved was 64.5% of the original concentration after 9 days. Gas chromatography analysis showed the complete mineralisation of C 7 -C 13 hydrocarbon chains. Fourier transform infrared spectroscopy analysis confirmed that strain WCY&#95;AQ5&#95;3 fully degraded the hydrocarbon with bioabsorption of the products. Morphological and molecular analyses suggested that this spherical, single-celled green microalga was a member of the genus Micractinium . The data obtained confirm that this microalga is a suitable candidate for further research into the degradation of diesel in Antarctica.

Brunei Bay is a unique ecosystem which offers a vast biodiversity. This study was carried out to define the source of metals in the surface sediment of Brunei Bay to ensure the bay's health. The secondary data were analysed using chemometrics analysis to verify the possible factors that influence metals distribution in Brunei Bay sediment. Samples were collected several times during 2013 to 2014 using Ponar grab at 16 stations within the bay. Samples were then dried, pre-treated, digested and analysed using Inductively Coupled Plasma Mass Spectrometry (ICPMS) in the laboratory. Overall, the mean concentration of metal, sediment pH and clay fraction were significantly changed during different sampling periods, as the changes were presumed affected by seasonal changes. The Pearson correlation has pointed that metals were dominantly derived by natural input; however, the total organic carbon was proven to be derived by anthropogenic sources. Moreover, the principal component analysis has verified that the distribution of metals in the bay's sediment was dominantly influenced by natural processes. However, the utilization and manipulation of marine resources are slightly affecting the bay's ecosystem which may deteriorate the ecosystem health soon., (© 2022. The Author(s), under exclusive licence to Springer Nature B.V.)

The reconstruction of fire history is essential to understand the palaeoclimate and human history. Polycyclic aromatic hydrocarbons (PAHs) have been extensively used as a fire marker. In this work, the distribution of PAHs in Borneo peat archives was investigated to understand how PAHs reflect the palaeo-fire activity. In total, 52 peat samples were analysed from a Borneo peat core for the PAH analysis. Pyrogenic PAHs consist of 2-7 aromatic rings, some of which have methyl and ethyl groups. The results reveal that the concentration of pyrogenic PAHs fluctuated with the core depth. Compared to low-molecular-weight (LMW) PAHs, the high-molecular-weight (HMW) PAHs had a more similar depth variation to the charcoal abundance. This finding also suggests that the HMW PAHs were mainly formed at a local fire near the study area, while the LMW PAHs could be transported from remote locations., Competing Interests: The authors have declared that no competing interests exist.

Poly(methyl methacrylate) (PMMA) is a lightweight insulating polymer that possesses good mechanical stability. On the other hand, polyaniline (PANi) is one of the most favorable conducting materials to be used, as it is easily synthesized, cost-effective, and has good conductivity. However, most organic solvents have restricted potential applications due to poor mechanical properties and dispersibility. Compared to PANi, PMMA has more outstanding physical and chemical properties, such as good dimensional stability and better molecular interactions between the monomers. To date, many research studies have focused on incorporating PANi into PMMA. In this review, the properties and suitability of PANi as a conducting material are briefly reviewed. The major parts of this paper reviewed different approaches to incorporating PANi into PMMA, as well as evaluating the modifications to improve its conductivity. Finally, the polymerization condition to prepare PMMA/PANi copolymer to improve its conductivity is also discussed.

Brain tumors diagnosis in children is a scientific concern due to rapid anatomical, metabolic, and functional changes arising in the brain and non-specific or conflicting imaging results. Pediatric brain tumors diagnosis is typically centralized in clinical practice on the basis of diagnostic clues such as, child age, tumor location and incidence, clinical history, and imaging (Magnetic resonance imaging MRI / computed tomography CT) findings. The implementation of deep learning has rapidly propagated in almost every field in recent years, particularly in the medical images' evaluation. This review would only address critical deep learning issues specific to pediatric brain tumor imaging research in view of the vast spectrum of other applications of deep learning. The purpose of this review paper is to include a detailed summary by first providing a succinct guide to the types of pediatric brain tumors and pediatric brain tumor imaging techniques. Then, we will present the research carried out by summarizing the scientific contributions to the field of pediatric brain tumor imaging processing and analysis. Finally, to establish open research issues and guidance for potential study in this emerging area, the medical and technical limitations of the deep learning-based approach were included.

Pulau Tioman is a famous tourist island off Peninsular Malaysia with beautiful coral reefs. This study aims to assess the health of the coral reefs surrounding Pulau Tioman based on the application of the Foraminifera in Reef Assessment and Monitoring Index (FI). Ten sampling sites around Pulau Tioman were studied with a total of 30 samples. Eight orders, 41 families, 80 genera, and 161 species of benthic foraminifera were identified. The agglutinated type of foraminifera constituted 2-8% of the total assemblages. Calcareous hyaline and porcelaneous groups represented 79% and 19% of the total assemblages, respectively. Symbiont-bearing taxa were the most common foraminifera. The results indicate that most of the sampling sites are conducive for coral reef growth with good recoverability from future stress to the ecosystem. However, several areas with higher coastal development and tourism have reduced water and sediment quality. Therefore, the limit on the number of visitors and tourists should be revised to enable coral growth and health. The FI values in this study showed a positive correlation with good water qualities and a negative correlation with organic matter enrichment. The FI is a good measure to assess the health of a coral reef and can be applied to other reef ecosystems around Malaysia.

Decommissioning of the offshore platform as an artificial reef, known as Rigs-to-Reefs (R2R), has become a sustainable approach for oil companies. The platform was reused to serve the underwater ecosystem as an artificial reef for a new marine ecosystem which helps to tackle food security issue. This paper presents the findings of the formulation of the reefing viability index to recognize an offshore region that can be used for R2R projects within the South China Sea. The combined effects of spatial data, numerical modelling, and geographic system (GIS) are proposed to study the relationship of spawning ground coral reefs, diversity, and planula larvae in the process of colonization to establish a map of the reef potential environment. Coral connectivity and spawning behaviour were studied to determine the possible source of coral seedling released during the spawning season, twice a year. A geographic reef viability index was established consisting of seven parameters which are coral larval density, pelagic larval length, sea currents, temperature, chlorophyll-a, depth, and substrate availability. The ocean hydrodynamic model was designed to resemble the pattern of larval scattering. By using the simulations and rankings, there were 95 (21%) sites which could probably be used for in situ reefing, whereas 358 (79%) sites were likely ideal for ex situ reefing. Validation of the viability index was carried out using media footage assessment of remotely operated vehicle (ROV)., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2020 Mohd Hairil Mohd et al.)

The groundwater samples of Pulau Bidong, Terengganu, Malaysia were collected from five sampling stations from June to October 2016. Physical parameters such as temperature, specific conductivity, dissolved oxygen (DO), pH, salinity, and DO saturation were measured in-situ by using handheld device. Meanwhile, total suspended solid (TSS), total dissolved solid (TDS), nitrate (NO 3 - ), nitrite (NO 2 - ), ammonium (NH 4 + ) and phosphate (PO 4 3- ) were analysed and detected using UV-Vis Spectrophotometer. The inorganic nutrients (NO 3 - , NO 2 - , NH 4 + and PO 4 3- ) were ranged from 0.000 to 4.310 mg/L, 0.000 to 0.190 mg/L, 0.000 to 0.807 mg/L and 0.003 to 0.028 mg/L, respectively. The monthly trends of specific conductivity, DO, salinity, DO saturation, NO 3 - , NO 2 - and NH 4 + demonstrated significant variation in June (the lowest rainfall) compared to other months. Correlation matrix revealed that temperature was associated with the specific conductivity, and NH 4 + strongly correlated with DO, NO 3 - and NO 2 - . Nevertheless, there is a strong negative correlation between physicochemical parameters and monthly rainfall distribution. Notably, future studies are required for long-term monitoring to ensure the good quality of groundwater from Pulau Bidong. The spatial and temporal variability of the present data has been reported by Tan et al. [1]., (© 2020 The Author(s).)

Objective: The aim of this study was to explore parents' awareness and usage of CRS, incentives and challenges in CRS use, as well as their perception about potential CRS legislation in Malaysia. Methods: This was a cross-sectional study conducted in a public tertiary care center in Northern Malaysia. A self-developed researcher-assisted questionnaire was developed in English and translated into Malay language, to explore parents' awareness ad CRS usage, as well as the incentives and barriers in CRS use. Parents of a newborn were conveniently sampled, excluding parents with pre-term newborn or those without a car. Upon obtaining written informed consent, the parents were allowed to answer the questionnaire within 20 minutes, assisted by the researchers. Parents who were found not using CRS for their newborn were given a digital pamphlet with CRS-related information via mobile devices. Results: A total of 200 parents were approached and 193 of them consented to participate in this study. The majority of the parents (87.6%) were aware of CRS, but only half of them (57.0%) provided a CRS for their current newborn. From 100 CRS users, most of them used a CRS for "child's safety" purposes (84.5%). Among 83 CRS nonuser, nearly half of them (45.8%) perceived that it is adequate to carry their child during traveling without using a CRS. When exploring previous experience in using CRS among all parents (n = 193), more than half of them (63.9%) faced difficulty as their child refused to use the CRS. More than half (54.9%) of all parents were not aware about the possible CRS legislation in Malaysia. However, the majority of them (90.7%) agreed with the implementation of CRS law. Conclusions: Although majority of the parents were aware about CRS, but only half had a CRS for their current newborn. Most of the parents supported CRS legislation in Malaysia, but assistance will be required to help them through challenges related to CRS use.