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Zika virus modulates blood-brain barrier of brain microvascular endothelial cells
No full textZika virus (ZIKV) is a mosquito-borne Flaviviruses. ZIKV is known to cause birth defect in pregnant women, especially microcephaly in the fetus. Hence, more study is required to understand the infection of Zika virus towards human brain microvascular endothelial cells (MECs). In this study, brain MECs were infected with ZIKV at MOI of 1 and 5 in vitro. The changes in barrier function and membrane permeability of ZIKV-infected brain MECs were determined using electric cell-substrate impedance sensing (ECIS) system followed by gene expression of ZIKV-infected brain MECs at 24 hours post infection using one-color gene expression microarray. The ECIS results demonstrated that ZIKV infection enhances vascular leakage by increasing cell membrane permeability via alteration of brain MECs barrier function. This was further supported by high expression of proinflammatory cytokine genes (lnc-IL6-2, TNFAIP1 and TNFAIP6), adhesion molecules (CERCAM and ESAM) and growth factor (FIGF). Overall, findings of this study revealed that ZIKV infection could alter the barrier function of brain MECs by altering adhesion molecules and inflammatory response. © 2019, Malaysian Society for Parasitology. All rights reserved
Foot Squamous Cell Carcinoma: Grieve Lessons from Diabetic Foot Ulcer Misdiagnosis
No full textFoot squamous cell carcinoma (SCC) is rare and preponderance towards DFU misdiagnosis is very likely given the high risk of developing DFU among diabetics. This case highlights the needs to identify atypical features observed in any given DFU to avoid misdiagnosis and late detection of malignant changes. A 63-year-old gentleman with diabetes presented with non-healing right DFU for more than two years. The ulcer was hypergranulating over medial surface of mid-foot, had minimal slough and irregular edges but no callosities. Treatments include debridement, dressing and strict offloading of right foot, but the ulcer remained unchanged. Skin biopsy confirmed the diagnosis of SCC and surgical resection was done but complicated with bone metastases at 4 months post-surgery. The patient died secondary to bilateral pulmonary embolism in less than a year since the diagnosis of SCC. Atypical features that triggered the possibility of DFU misdiagnosis are: 1) prolonged non-healing DFU despite appropriate ulcer management and addressing factors affecting wound healing, 2) foot ulcer pain with no callosities typically observed in DFU, and 3) hypergranulating ulcer in a well-controlled diabetes. Reported cases of foot SCC were primarily over the heel, an area with high contact and pressure load during walking. In this case, the absence of great toe (acquired from old trauma) had possibly altered pressure distribution of the foot leading to atypical ulcer’s location. Prolonged non-healing DFU despite appropriate ulcer management and addressing factors affecting wound healing, with atypical clinical features should raise caveat of DFU misdiagnosis. © Copyright 2019 by Gazi University Medical Facult
Effect of pH, Acid and Thermal Treatment Conditions on Co/CNT Catalyst Performance in Fischer–Tropsch Reaction
No full textMultiwalled carbon nanotubes (CNT) supported cobalt oxide was prepared as a catalyst by strong electrostatic adsorption (SEA) method. The CNT support was initially acid- and thermal-treated in order to functionalize the support to uptake more Co clusters. The Co/CNT were characterized by a range of analytical methods including transmission electron microscopy (TEM), temperature programmed reduction with hydrogen (H2-TPR), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, atomic absorption spectroscopy (AAS), Zeta sizer particle size analysis and Brunauer-Emmett-Teller (BET) surface area analysis. TEM images showed cobalt particles were highly dispersed and impregnated at both exterior and interior walls of the CNT support with a narrow particle size distribution of 6-8 nm. In addition, the performance of the synthesized Co/CNT catalyst was tested using Fischer-Tropsch synthesis (FTS) reaction which was carried out in a fixed-bed micro-reactor. H2-TPR profiles indicated the lower reduction temperature of 420 °C was required for the FTS reaction. The study revealed that cobalt is an effective metal for Co/CNT catalysts at pH 14 and at 900 °C calcination temperature. Furthermore, FTS reaction results showed that CO conversion and C5+ selectivity were recorded at 58.7% and 83.2% respectively, which were higher than those obtained using a Co/CNT catalyst which pre-treated at a lower thermal treatment temperature and pH. © 2019 by the authors
Response surface approach for visible light assisted photocatalytic degradation of ortho nitrophenol by magnetically separable TiO2/CS nanocomposite
No full textVisible light induces photocatalytic degradation technology has gained increasing interest in the treatment of organic pollutants for the wastewater system. In this study, magnetically separable nanocomposite (M-TiO 2 /CS) was successfully synthesized with a narrow band gap (2.85 eV) than pure TiO 2 . A central composited design (CCD) coupled with response surface methodology (RSM) was effectively utilized to inquire about the photocatalytic degradation of ONP degradation by using M-TiO 2 /CS. Three independent factors including the M-TiO 2 /CS loading, initial ONP concentration, and pH of the solution were examined in details. Based on the results obtained from RSM analyses, an efficient pathway leading to the high degradation rate (92%) was achieved by applying 0.02 g of M-TiO 2 /CS dosage with 30 mg/L of a concentration of ONP at pH 6 for 180 min. The experimental results fit well with the derived response model (R 2 = 0.9789). The current study proposed a cost-effective and highly efficient approach to wastewater pollution issues. © 201
Analysis of the interface pressure exerted by the Chêneau brace in patients with double-curve adolescent idiopathic scoliosis
No full textThe Chêneau brace has proven its effectiveness in treating the adolescent idiopathic scoliosis patients. However, no studies reported on the analysis of interface pressure in double-curve adolescent idiopathic scoliosis patients. In this study, we evaluated the interface pressure of the Chêneau brace action in double-curve adolescent idiopathic scoliosis patient treatment. A total of 72 (60 girls and 12 boys) patients aged 10 years and above participated in the study. The F-Socket transducers (9811E) were used to evaluate the pressure on the right thoracic and left thoracolumbar curves between normal and maximum strap tension and variation in these interface pressures with other tasks. Each patient was asked to do nine different tasks corresponding to daily activities, and the interface pressures for each activity were recorded for both normal and maximum tension. The resultant mean peak pressure in double-curve adolescent idiopathic scoliosis was higher for right thoracic curves than left thoracolumbar curves in all tasks. The pressure significantly increased at the task of maximal inspiration (p < 0.0001) for both types of curves for normal and maximum tension. The degrees of correction for the thoracic and thoracolumbar curves were 23.2% and 34.5%, respectively, after 6 months of brace use (23 h per day). Hence, we could not find any substantial correlation between mean peak pressure in the standing position and degree of scoliosis correction for two curves having r = 0.158, p = 0.356 and r = –0.024, p = 0.889 values. © IMechE 2019
Mode-locked pulse generation in erbium-doped fiber laser by evanescent field interaction with reduced graphene oxide-titanium dioxide nanohybrid
No full textIn this work, a new nanohybrid saturable absorber (SA)is successfully fabricated from reduced graphene oxide (rGO)nanosheets and titanium dioxide (TiO2)nanoparticles. The nanohybrid material is synthesized using the simple and inexpensive hydrothermal technique. The SA is fabricated by depositing the nanohybrid solution onto a D-shaped fiber in an erbium-doped fiber (EDF)laser cavity. The evanescent wave interaction between the incident light and rGO-TiO2 nanohybrid material induces mode-locking in the EDF laser at the threshold pump power of 100.80 mW. A stable soliton pulse with a center wavelength of 1560.45 nm and 3-dB bandwidth of 2.47 nm is obtained. The generated pulses have a repetition rate and pulse width of 11.19 MHz and 1.05 ps at the highest pump power of 268.10 mW. The proposed rGO-TiO2 nanohybrid of this work is a promising SA material for generating mode-locking in an EDF laser for optical modulation applications. © 201
Q-switched Ytterbium doped fibre laser using gold nanoparticles saturable absorber fabricated by electron beam deposition
No full textA stable Q-switched Ytterbium doped fibre laser (YDFL) is demonstrated based on ring cavity by incorporating gold nanoparticles (AuNPs) based saturable absorber (SA). The SA is fabricated by depositing AuNPs onto polyvinyl alcohol thin-film surface using electron beam deposition technique. The proposed laser generates Q-switching pulses train as the pump power is increased beyond 61.1 mW. The laser operates at 1063.5 nm with the maximum repetition rate of 61.88 kHz and the thinnest pulse width of 4.23 μs are recorded at the 87.3 mW pump power. The output power increases linearly up to 3.14 mW, while the pulse energy varies from 10.55 nJ to 50.74 nJ as a pump power increased. Meanwhile, the maximum peak power of 12 mW is obtained at the pump power of 87.3 mW. © 2019 Elsevier Gmb
Potential antioxidants from crude extracts of roselle seeds and cashew nut shells for biodiesel storage stability improvement
Get PDFBiodiesel or fatty acid methyl ester (FAME) is a green alternative fuel that degrades under long-term storage. Antioxidants are utilized in maintaining the oxidation stability of biodiesel by inhibiting the propagation of free radicals resulting in prolonged shelf life. Usage of natural antioxidants from renewable resources is preferred to sustain a green economy and potentially match synthetic antioxidants without being hazardous to the environment. In this study, the potential of antioxidants from crude extracts of Roselle seeds (Hibiscus sabdariffa) and cashew nut shells (Anacardium occidentale) which are agricultural residues that are commonly left unconsumed has been tested for biodiesel storage stability improvement. ABTS antioxidation test on both plant parts showed significant results for all samples regardless of their polarity while β-Carotene test favored polar samples. Positive correlation of DPPH test and total phenolic content (TPC) test confirmed the antioxidant activity of phenolic compounds in all samples. Total flavonoid content (TFC) test also showed positive results for all samples. GC-MS and LC-MS profiling of both plant parts revealed that all samples contained phenolic compounds with the exception of roselle seeds extracted with hexane (RH), which contained mostly fatty acids. Oxidative stability test using Rancimat test showed that polar samples have superior performance than nonpolar samples whereas 3-pentadecyl phenol showed a poor performance in improving biodiesel storage stability
Hydrolysis of microcrystalline cellulose isolated from waste seeds of Leucaena leucocephala for glucose production
Get PDFThe waste seeds of Leucaena leucocephala (LLS) used in this study were unused residues obtained after oil and polysaccharides extraction. The microcrystalline cellulose (MCC) was isolated from LLS by acid treatment. MCC produced was, then, further converted to glucose by using sulphuric acid at 121 °C by varying the acid concentration and reaction time. The sugar composition was analyzed by using the phenol-sulfuric acid method and pre-column derivatization HPLC technique. The yield of glucose ranging from 70–85% could be obtained from MCC hydrolyzates, depending on the hydrolysis factors, which corresponding to around 57-75% of the percentage conversion of MCC to glucose.Cellulose isolated from LLS was, therefore, potentially suitable to be utilized in liquid biofuels and other value-added chemicals such as bioethanol, 5-hydroxymethylfurfural(HMF), and levulinic acid
Validation of the Malay Version of Addenbrooke’s Cognitive Examination III in Detecting Mild Cognitive Impairment and Dementia
No full textBackground/Aims: This study aimed to investigate the validity and reliability of the Malay version of Addenbrooke's Cognitive Examination III (ACE-III) for detecting mild cognitive impairment (MCI) and dementia. Methods: A total of 152 participants (dementia = 53, MCI = 38, controls = 61) were recruited from two teaching hospitals. The Malay version of ACE-III was translated following the standard guidelines for cross-cultural adaptation of measure. All the participants were assessed with the Malay version of ACE-III and Mini-Mental State Examination (MMSE). Results: The reliability of the Malay version of ACE-III was good with Cronbach's α coefficient of 0.829 and intraclass correlation coefficient of 0.959. There was a strong positive correlation between the Malay version of ACE-III and MMSE (r = 0.806). Age (r = -0.335) and years of education (r = 0.536) exerted a significant correlation with total score performance. The cutoff score to discriminate dementia from healthy controls was 74/75 (sensitivity = 90.6%, specificity = 82.0%) whereas to discriminate MCI, the cutoff score was 77/78 (sensitivity = 63.2%, specificity = 63.9%). The diagnostic accuracy of ACE-III was higher than that of MMSE in the detection of dementia (area under the curve: ACE-III = 0.929 vs. MMSE = 0.915). Conclusions: The Malay version of ACE-III demonstrated to be a reliable and valid screening tool for dementia. © 2019 The Author(s) Published by S. Karger AG, Basel