300 research outputs found
Newer Diagnostics for Dengue Disease
No full textBiosensor technology can circumvent the limitations while retaining almost all the advantages of laboratory-based diagnostics. Biosensors are analytical devices that involve integration between a molecular recognition platform with a physicochemical transducer to produce a single detection processing unit. The suitability of biosensors is evaluated by a set of parameters based on the International Union of Pure and Applied Chemistry guidelines, which include specificity, selectivity, limit of detection, and sensitivity. Electrochemical biosensors for dengue detection have become the overwhelming method of choice among researchers due to their ability to be highly quantitative and qualitative. Much attention is placed on the transducer surface selection, which immobilizes the biorecognition element. Antibodies, which are amongst the most exquisitely designed and engineered molecules in nature, play a vital role in a number of sensor devices, due to their exquisite target specificity and affinity. Antibodies are ideal biorecognition elements that provide sensors with high specificity and sensitivity
Quintuplex PCR to detect antibiotic resistance genes in Streptococcus pneumoniae / Navindra Kumari Palanisamy, Parasakthi Navaratnam and Shamala Devi Sekaran
No full textStreptococcus pneumoniae is an important bacterial pathogen, causing respiratory infection. Penicillin resistance in S. pneumoniae is associated with alterations in the penicillin binding proteins, while resistance to macrolides is conferred either by the modification of the ribosomal target site or efflux mechanism. This study aimed to characterize S. pneumoniae and its antibiotic resistance genes using 2 sets of multiplex PCRs
The epidemiology of pneumococcal carriage and infections in Malaysia
No full textIn Malaysia, various aspects of the epidemiology of pneumococcal carriage and disease remain largely unclear due to the lack of supporting data. Although a number of relevant studies have been documented, their individual discrete findings are not sufficient to inform experts on pneumococcal epidemiology at a national level. Therefore, in this review we aim to bring together and systematically evaluate the key information regarding pneumococcal disease epidemiology in Malaysia and provide a comprehensive overview of the data. Major aspects discussed include pneumococcal carriage, disease incidence and prevalence, age factors, invasiveness of pneumococci, serotypes, molecular epidemiology and antibiotic susceptibility. Penicillin resistance is increasingly prevalent and studies suggest that the majority of pneumococcal serotypes causing pneumococcal disease in Malaysia are covered by currently available conjugate vaccines. Continued surveillance is needed to provide a better understanding of pneumococcal epidemiology in Malaysia
Novel clones of Streptococcus pneumoniae causing invasive disease in Malaysia.
No full textAlthough Streptococcus pneumoniae is a leading cause of childhood disease in South East Asia, little has previously been reported regarding the epidemiology of invasive pneumococcal disease in Malaysia and very few studies have explored pneumococcal epidemiology using multilocus sequence typing (MLST). Here we describe serotype, multilocus sequence type (ST), and penicillin susceptibility of thirty pneumococcal invasive disease isolates received by the University of Malaya Medical Centre between February 2000 and January 2007 and relate this to the serotypes included in current pneumococcal conjugate vaccines. A high level of diversity was observed; fourteen serotypes and 26 sequence types (ST), (11 of which were not previously described) were detected from 30 isolates. Penicillin non-susceptible pneumococci accounted for 33% of isolates. The extent of molecular heterogeneity within carried and disease-causing Malaysian pneumococci remains unknown. Larger surveillance and epidemiological studies are now required in this region to provide robust evidence on which to base future vaccine policy
Identifying Adult Dengue Patients at Low Risk for Clinically Significant Bleeding.
No full textBACKGROUND:Clinically significant bleeding is important for subsequent optimal case management in dengue patients, but most studies have focused on dengue severity as an outcome. Our study objective was to identify differences in admission parameters between patients who developed clinically significant bleeding and those that did not. We sought to develop a model for discriminating between these patients. METHODS:We conducted a retrospective study of 4,383 adults aged >18 years who were hospitalized with dengue infection at Tan Tock Seng Hospital, Singapore from 2005 to 2008. Patients were divided into those with clinically significant bleeding (n = 188), and those without (n = 4,195). Demographic, clinical, and laboratory variables on admission were compared between groups to determine factors associated with clinically significant bleeding during hospitalization. RESULTS:On admission, female gender (p38°C (p38°C (aOR 1.81; 95% CI: 1.27-2.61), nausea/vomiting (aOR 1.39; 95% CI: 0.94-2.12), ANC (aOR 1.3; 95% CI: 1.15-1.46), ALC (aOR 0.4; 95% CI: 0.25-0.64), hematocrit percentage (aOR 0.96; 95% CI: 0.92-1.002) and platelet count (aOR 0.993; 95% CI: 0.988-0.998). At the cutoff of -3.919, the model achieved an AUC of 0.758 (sensitivity:0.87, specificity: 0.38, PPV: 0.06, NPV: 0.98). CONCLUSION:Clinical risk factors associated with clinically significant bleeding were identified. This model may be useful to complement clinical judgement in triaging adult dengue patients given the dynamic nature of acute dengue, particularly in pre-identifying those less likely to develop clinically significant bleeding
Molecular interaction study on Gemini surfactant and nanoparticles in wax inhibition of Malaysian crude oil
No full textWax deposition can cause a slowdown in operation by restricting crude oil flow in the pipeline. Chemical inhibitors interact with the wax molecule in crude oil and prevent wax aggregation. The molecular dynamics (MD) simulation was used to analyze the intermolecular interaction between a wax molecule of n-icosane and a Gemini surfactant 2,5,8,11 tetramethyl 6 dodecyn-5,8 diol ethoxylate (GS) with three distinct nanoparticles: silicon dioxide (SiO2)(NP1), tin oxide (SnO)(NP2), and nickel oxide (Ni2O3)(NP3). The desired structural feature of the radial distribution function (rdf) was analyzed using the COMPASS force field. Weakest intermolecular interaction between n-icosane (highest rdf value of 5.25 Å), indicating high wax solubility, was achieved in the presence of GS/NP3 blend. In addition, GS/NP3 blend gave the strongest van der Waals (vdW) interaction with a hydrogen atom in n-icosane. The presence of the O carbonyl group in both GS and NP3 establishes a higher number of hydrogen bonds. Thus, the GS/NP3 blend acts as the best inhibitor compared to the individual GS and NP3. The simulation analysis on the degree of wax formation reduction using GS/NP3 blend correlated well with cold finger experiment that showed a wax formation reduction of 61.6%
Characterization of Enzymes Produced by Bacillus species
No full textThis Dissertation / Report is the outcome of investigation carried out by the creator(s) / author(s) at the department/division of Central Food Technological Research Institute (CFTRI), Mysore mentioned below in this page
Nanoparticle assisted gemini surfactant as wax deposition suppressant in Malaysian crude oil using experimental and molecular dynamics simulation
No full textWax deposition can cause a slowdown or halt in operation by restricting crude oil flow in the pipeline due to the wax blockage and triggering pressure irregularities. Chemical inhibitors interact with the wax molecule in crude oil and prevent large wax molecules from attach. The use of Gemini surfactant and nanoparticles to prevent wax deposition is still in its infancy. In this thesis, the efficiency of Gemini surfactant 2,5,8,11 Tetramethyl 6 dodecyn-5,8 Diol Ethoxylate (GS), three different nanoparticles: silicon dioxide (NP1), tin oxide (NP2) and nickel (III) oxide (NP3) and their blends at different operating conditions are assessed to study their influence on the crude oil viscosity using Brookfield DV-III viscometer and wax inhibition using cold finger analysis. In addition, molecular dynamics modeling (MD) is used to analyze the intermolecular interaction between a wax molecule (n-icosane) with inhibitors using Accelrys Material Studio 8. The interaction of wax molecules with inhibitors were analysed through radial distribution function (rdf) value. The separate use of GS and nanoparticles significantly reduced crude oil viscosity and wax deposition. However, combining the GS and nanoparticles showed better performance than their corresponding individual use in viscosity and cold finger analysis. Overall, the viscosity of crude oil was reduced by about 85-92% at 10℃ with the addition of GS and nanoparticles. The highest viscosity reduction obtained was 92.8% using the blend of GS and NP1. The addition of nanoparticles to GS improved their inhibition efficiency by providing dispersion. Nevertheless, the use of GS and nanoparticles individually achieved a paraffin inhibition efficiency (PIE) of 45-48%. The highest PIE of 61.6% was achieved by GS/NP3 blend while the lowest was 45.3% with NP1 individual used. For the MD results, GS/NP3 blend shows the weakest wax-wax intermolecular interaction with n-icosane, indicating higher wax solubility with the highest radial distribution function (rdf) value of 5.25 Å. Also, the GS/NP3 blend has the stronger van der Waals (vdW) interaction with a hydrogen atom in n-icosane compared to the individual systems of GS and NP3 separately. This can be due to the presence of the O carbonyl group in both GS and NP3, which can establish a higher number of bonds. Therefore, wax inhibition in n-icosane is higher in GS/NP3 blend compared to the individual system of GS and NP3. An experimental study through cold finger analysis validated simulation result which proved that the GS/NP3 blend significantly reduced the wax formation by 61.6%. In comparison, the individuals of GS and NP3 reduced wax formation by 46.5% and 47.7% respectively. Overall, the combination of GS and NP3 has shown highest efficiency in wax inhibition through cold finger analysis and highest wax solubility in rdf analysis. Thus, GS/NP3 blend is the best inhibitor among tested inhibitor combinations in inhibiting wax in Malaysian crude oil
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