19672 research outputs found
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Parasite contamination of freshly harvested vegetables from selected organic and conventional farms in the Philippines
No full textVegetables are considered as an important part of a healthy diet. However, there have been reports showing contamination of vegetables with parasites. This study aimed to assess parasite contamination of freshly harvested vegetables from selected organic and conventional farms in the Philippines. A total of 252 freshly harvested vegetables were collected from 20 farms through systematic random sampling and were processed by means of sedimentation technique. Positive samples were subjected to molecular analysis for further identification of species. Results showed that 58 out of 252 (23.02%) vegetable samples were contaminated with parasites eggs/cysts/oocysts. The parasites found were Ancylostoma ceylanicum, Toxocara sp., Trichuris trichiura, Ascaris suum, Hymenolepis sp., unknown trematode egg, Isospora, Balantidium, Giardia intestinalis and Cryptosporidium. Ascaris suum had the highest contamination rate in organic and conventional farms at 13.09% and 8.33%, respectively. Cryptosporidium (≥800 oocysts/ kg) and Giardia intestinalis (≥240 cysts/kg) had the highest mean density in both farms. Also, lettuce showed the highest contamination rate among the sampled vegetables in both types of farms. Furthermore, results revealed that texture of vegetables, distance to the soil substrate, and farming practices could possibly contribute to the parasite contamination of vegetables in this study. These findings have important implications on public health that may aid regulatory agencies for prevention and control strategies for food safety
The role of human Metapneumovirus genetic diversity and nasopharyngeal viral load on symptom severity in adults
No full textBackground: Human metapneumovirus (HMPV) is established as one of the causative agents of respiratory tract infections. To date, there are limited reports that describe the effect of HMPV genotypes and/or viral load on disease pathogenesis in adults. This study aims to determine the role of HMPV genetic diversity and nasopharyngeal viral load on symptom severity in outpatient adults with acute respiratory tract infections. Methods: Severity of common cold symptoms of patients from a teaching hospital was assessed by a four-category scale and summed to obtain the total symptom severity score (TSSS). Association between the fusion and glycoprotein genes diversity, viral load (quantified using an improved RT-qPCR assay), and symptom severity were analyzed using bivariate and linear regression analyses. Results: Among 81/3706 HMPV-positive patients, there were no significant differences in terms of demographics, number of days elapsed between symptom onset and clinic visit, respiratory symptoms manifestation and severity between different HMPV genotypes/sub-lineages. Surprisingly, elderly patients (≥65 years old) had lower severity of symptoms (indicated by TSSS) than young and middle age adults (p = 0.008). Nasopharyngeal viral load did not correlate with nor predict symptom severity of HMPV infection. Interestingly, at 3-5 days after symptom onset, genotype A-infected patients had higher viral load compared to genotype B (4.4 vs. 3.3 log 10 RNA copies/μl) (p = 0.003). Conclusions: Overall, HMPV genetic diversity and viral load did not impact symptom severity in adults with acute respiratory tract infections. Differences in viral load dynamics over time between genotypes may have important implications on viral transmission
Increase in convective heat transfer over a backward-facing step immersed in a water-based tio2 nanofluid
No full textInvestigation of flow separation and reattachment of 0.2% water-based TiO2 nanofluid in an annular suddenly expanding pipe is presented in this paper. Such flows occur in various engineering and heat transfer applications. A computational fluid dynamics package (FLUENT) is used to study turbulent nanofluid flow in this research. Only a quarter of an annular pipe was investigated and simulated because of its symmetrical geometry. Standard k–ε second-order implicit, pressure based-solver equations are applied. Reynolds numbers between 17,050 and 44,545, step height ratio of 1.82, and a constant heat flux of 49,050 W/m2 were utilized in simulation. The numerical simulation results show that increase in the Reynolds number leads to an increase of the heat transfer coefficient and of the Nusselt number. Moreover, the surface temperature dropped to its lowest value after the expansion and then gradually increased along the pipe. Finally, the chaotic movement and high thermal conductivity of the TiO2 nanoparticles have contributed to the overall heat transfer enhancement of the nanofluid
Antifungal and cytotoxic activities of extracts obtained from underutilised edible tropical fruits
No full textObjective: To evaluate antifungal and cytotoxic activities of four underutilised fruit species, i.e. Artocarpus altilis (breadfruit), Cynometra cauliflora (nam-nam), Mangifera pajang (M. pajang) (Bambangan) and Physalis minima (wild gooseberry). Methods: Extracts from the fresh flesh of Artocarpus altilis and Cynometra cauliflora, the flesh and kernel of M. pajang, and the whole fruit of Physalis minima were obtained by sequential extraction using hexane, chloroform, ethyl acetate, ethanol, methanol and distilled water. Each extract was assessed against six species of human fungal pathogens using a colourimetric broth microdilution method. The cytotoxicity was evaluated using African monkey kidney epithelial (Vero) cells. Results: All 30 extracts showed inhibitory activity against Cryptococcus neoformans. However, none of the extracts were active against Aspergillus fumigatus. The ethanol, methanol and water extracts from the kernel of M. pajang fruit showed the strongest activity against three species of Candida and Trichophyton interdigitale, with a minimum inhibitory concentration range of 0.001 - 0.630 mg/mL. The corresponding mean 50% cytotoxic concentrations for these three extracts were 358.7, 158.4 and 261.3 μg/mL, respectively against Vero cells. In contrast, the flesh of M. pajang fruit (hexane, chloroform and ethyl acetate extracts) showed statistically significant (P<0.001; ANOVA) strong toxicity against the cells, with 30.6, 13.5 and 22.2 μg/mL of mean values of 50% cytotoxic concentrations, respectively. Conclusions: The results suggest that the bioactivity of the kernel of M. pajang fruit is more selective towards fungi and thus is a potential source of new antifungal agents
Engineering a stable CHO cell line for the expression of a MERS-coronavirus vaccine antigen
No full textMiddle East respiratory syndrome coronavirus (MERS-CoV) has infected at least 2040 patients and caused 712 deaths since its first appearance in 2012, yet neither pathogen-specific therapeutics nor approved vaccines are available. To address this need, we are developing a subunit recombinant protein vaccine comprising residues 377–588 of the MERS-CoV spike protein receptor-binding domain (RBD), which, when formulated with the AddaVax adjuvant, it induces a significant neutralizing antibody response and protection against MERS-CoV challenge in vaccinated animals. To prepare for the manufacture and first-in-human testing of the vaccine, we have developed a process to stably produce the recombinant MERS S377-588 protein in Chinese hamster ovary (CHO) cells. To accomplish this, we transfected an adherent dihydrofolate reductase-deficient CHO cell line (adCHO) with a plasmid encoding S377-588 fused with the human IgG Fc fragment (S377-588-Fc). We then demonstrated the interleukin-2 signal peptide-directed secretion of the recombinant protein into extracellular milieu. Using a gradually increasing methotrexate (MTX) concentration to 5 μM, we increased protein yield by a factor of 40. The adCHO-expressed S377-588-Fc recombinant protein demonstrated functionality and binding specificity identical to those of the protein from transiently transfected HEK293T cells. In addition, hCD26/dipeptidyl peptidase-4 (DPP4) transgenic mice vaccinated with AddaVax-adjuvanted S377-588-Fc could produce neutralizing antibodies against MERS-CoV and survived for at least 21 days after challenge with live MERS-CoV with no evidence of immunological toxicity or eosinophilic immune enhancement. To prepare for large scale-manufacture of the vaccine antigen, we have further developed a high-yield monoclonal suspension CHO cell line
Electrical and luminescence properties of MEH-PPV vertical organic light-emitting transistors with an ultra-thin aluminum source electrode
No full textPoly[2-methoxy-5-(2'-ethylhexyloxy)-p-phenylene vinylene] (MEH-PPV) based vertical organic light-emitting transistors (VOLETs) have been fabricated. The VOLETs were constructed with a bulk layer of indium-tin-oxide (ITO) and poly(2,3dihydrothieno-1,4-dioxin)–poly(styrenesulfonate) (PEDOT:PSS) as a drain, organic electroluminescent layer of MEH-PPV, an ultra-thin aluminum (Al) as a source, lithium fluoride (LiF) as dielectric and a thick Al as a gate. Electrical and luminescence properties of the devices were investigated. In such VOLETs, the negative bias on the gate electrode has induced a high current density and brighter luminescence, which corresponding to a strong energy band bending in the MEH-PPV layer. Device physics of the fabricated VOLETs were discussed in detail
Development of an ankle foot orthosis for hemiplegic children
No full textHemiplegia is a half body paralysis which causes disability in mobility function. Hemiplegia is normally discovered since early birth and is not curable. Treatment such as physical therapy can be carried out for the hemiplegic patient to prevent muscle contraction, especially at the early age. In this research, a tool for the physical therapy and gait assistance known as ankle foot orthosis (AFO) was developed for the hemiplegic children. The AFO was based on the active concept that mobilised the ankle by preventing excessive plantarflexion and allowed dorsiflexion. A linear type DC (direct current) motor was used as the actuator. The maximum range of motion (ROM) was +20° for the dorsiflexion and -20° for plantarflexion movement. The prototype was fabricated using 3D printing. Simple control for the device was developed using Arduino kits. The development of a new AFO is hoped to support the rehabilitation of the hemiplegic children
Efficient estimation in ZIP models with applications to count data
No full textEstimating functions have been used in estimating parameters of many continuous time series models. However, this method has not been applied to models involving count data. In this paper, we use quadratic estimating functions (QEF) to derive estimators for the joint estimation of the conditional mean and variance parameters of count data models, specifically the basic zero-inflated Poisson (ZIP) model, ZIP regression model and integer-valued generalized autoregressive heteroscedastic model with ZIP conditional distribution. Results show that the estimators derived from QEF method, which uses information from combined estimating functions, is more informative than linear estimating functions (LEF) method that only uses information from component estimating functions. Finally, we also fit the real data sets using the ZIP models via QEF, LEF and maximum likelihood methods, and in so doing, demonstrate the superiority of the QEF method in practice
Effect of diethylaminoethyl-dextran coated liposomes on the rheological properties of carbopol gel
No full textLiposomal gel has played an important role in administration of drugs via topical and transdermal routes. Incorporation of liposome into gel not only has overcome the liquid nature of liposomal dispersion but also helped to preserve the original structure of liposome. In this study, we formulated a liposomal gel consisting of Carbopol gel and a diethylaminoethyl dextran (DEAE-DX) coated liposome. The effect of coated and non-coated liposomes on the rheological properties of Carbopol gel was investigated. The rheological results indicated that incorporation of liposomes into Carbopol gel modified the viscoelastic and flow behaviour of the gel significantly. Apart from that, liposomal gel consisting of DEAE-DX coated liposomes exhibited more solid-like behavior compared to the non-coated liposomal gel. Incorporation of DEAE-DX coated liposomes increased the yield stress of liposomal gel compared to non-coated liposomes. This supports the findings obtained from the amplitude and frequency tests whereby addition of DEAE-DX enhanced the rigidity of the gel so that the resultant gel was more resistant to flow
Does income inequality affect environmental sustainability? Evidence from the ASEAN-5
No full textIncome gap among the Association of Southeast Asian Nations (ASEAN) has widened, while environment degradation has worsened since the 1990s. Using the Gini coefficient as a measure of income inequality, this paper attempts to examine whether the increasing income gap would have adverse effects on environmental sustainability and the causality relationship between income inequality and environmental sustainability. Using data from the World Bank and the Standardized World Income Inequality Database, this paper deployed the Granger causality and panel regression tests to examine these relationships on the ASEAN members of Indonesia, Malaysia, the Philippines, Thailand and Vietnam over the period of 1985–2015. The empirical results indicate that bi-directional causality relationship between income inequality and environmental sustainability exists among the bottom 40%, but the causality relationship results for the overall sample are mixed. The evidence shows that policy-makers in these countries should reduce income inequality to strengthen environmental sustainability