Separation technique on proteins via a pH-Parametric pump : a theoretical and experimental study

The separation of protein mixtures via pH-parametric pumping was investigated both theoretically and experimentally. A simple system consisting of one column packed either with cation or anion exchanger was first considered. A system of parapumps was then developed with more columns which were connected in series and packed alternately with cation and anion exchangers. Various methods of operation of parapumps are discussed. Enrichment and spliting of protein mixtures were examined. In most cases, the separation factor was defined at a steady state condition and was improved by increasing the number of cycles and columns. Computational methods for predicting both Batch and Semi-Continuous parametric pump performance, with equilibrium conditions described were developed. The physical system was characterized by means of interphase mass transfer rates. These methods were based on a set of exterior and interior material balances. Linear parameters were calculated for the adsorption of the solute on the ion exchanger. A mathematical model based on elementary matrix algebra was developed as well as a graphical method. The properties of eigenvalues and eigenvectors of this formalism were studied. The subject was extended to more complex situations involving a multi-column, and the separation of multi-protein. There is good agreement between predicted and experimental results

Temperature dependence of a magnetically levitated electromagnetic vibration energy harvester

 This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record Data accessibility: All data supporting this study are openly available from the University of Southampton repository at http://dx.doi.org/10.5258/SOTON/381135.Electromagnetic vibration energy harvesters including magnetically levitated devices where opposing magnets are used to form the spring have been well documented. The strength of the magnets naturally has a large influence on the dynamic characteristics and output power of such harvesters. However, it can be affected by ambient temperatures which vary from applications to applications. This paper presents investigation into the performance of a magnetically levitated electromagnetic energy harvester under various ambient temperatures. Parameters investigated include magnetic flux density, resonant frequency, damping ratio, open circuit output voltage, velocity of the relative motion and the load resistance. Both simulation and experimental results show that these properties vary with ambient temperatures. The magnetic flux density reduces as the temperature increases which results in lower resonant frequency, lower relative velocity, lower open circuit output voltage and higher damping ratio. Varying resonant frequencies with temperature can lead to harvesters being de-tuned from the target vibration frequency. Decreasing magnetic field strength and increased damping ratios will also reduce output power even if the harvester's resonant frequency still matches the environmental vibration frequency. The power transferred to the electrical load will be reduced due to the variation in the optimal load resistance with temperature. This means the harvester is no longer matched to achieve the maximum harvested power. The specified maximum operating temperature of the magnets was found to lead to partial demagnetisation. When cycling from room to the maximum specified temperature, the magnetic field was initially found to fall but remained constant thereafter. Harvesters were found to operate beyond the specified maximum operating temperature of the magnet, but suffer from a reduced magnetic strength.Engineering and Physical Sciences Research Council (EPSRC

Design optimization of a magnetically levitated electromagnetic vibration energy harvester for body motion

This paper presents a magnetically levitated electromagnetic vibration energy harvester based on magnet arrays. It has a nonlinear response that extends the operating bandwidth and enhances the power output of the harvesting device. The harvester is designed to be embedded in a hip prosthesis and harvest energy from low frequency movements (< 5 Hz) associated with human motion. The design optimization is performed using Comsol simulation considering the constraints on size of the harvester and low operating frequency. The output voltage across the optimal load 3.5k? generated from hip movement is 0.137 Volts during walking and 0.38 Volts during running. The power output harvested from hip movement during walking and running is 5.35 ?W and 41.36 ?W respectivel

Use of taste-masking product, FLAVORx, to assist Thai children to ingest generic antiretrovirals

We evaluated whether FLAVORx helped thirty Thai children take opened capsule, crushed tablets and liquid generic ARVs with more ease. All children had excellent adherence, evaluated by PACTG Standard International Questionnaire and interviewing, before and after one month of FLAVORx. Eighty percent took ARV with more ease and wish to continue FLAVORx. Strawberry was the most popular flavor

Immunologic and virologic failure after first-line NNRTI-based antiretroviral therapy in Thai HIV-infected children

<p>Abstract</p> <p>Background</p> <p>There are limited data of immunologic and virologic failure in Asian HIV-infected children using non-nucleoside reverse transcriptase inhibitor (NNRTI)-based highly active antiretroviral therapy (HAART). We examined the incidence rate of immunologic failure (IF) and virologic failure (VF) and the accuracy of using IF to predict VF in Thai HIV-infected children using first-line NNRTI-based HAART.</p> <p>Methods</p> <p>Antiretroviral (ART)-naïve HIV-infected children from 2 prospective cohorts treated with NNRTI-based HAART during 2001-2008 were included. CD4 counts were performed every 12 weeks and plasma HIV-RNA measured every 24 weeks. Immune recovery was defined as CD4%≥25%. IF was defined as persistent decline of ≥5% in CD4% in children with CD4%<15% at baseline or decrease in CD4 count ≥30% from baseline. VF was defined as HIV-RNA>1,000 copies/ml after at least 24 weeks of HAART. Clinical and laboratory parameter changes were assessed using a paired t-test, and a time to event approach was used to assess predictors of VF. Sensitivity and specificity of IF were calculated against VF.</p> <p>Results</p> <p>107 ART-naive HIV-infected children were included, 52% female, % CDC clinical classification N:A:B:C 4:44:30:22%. Baseline data were median (IQR) age 6.2 (4.2-8.9) years, CD4% 7 (3-15), HIV-RNA 5.0 (4.9-5.5) log₁₀copies/ml. Nevirapine (NVP) and efavirenz (EFV)-based HAART were started in 70% and 30%, respectively.</p> <p>At 96 weeks, none had progressed to a CDC clinical classification of AIDS and one had died from pneumonia. Overall, significant improvement of weight for age z-score (p = 0.014), height for age z-score, hemoglobin, and CD4 were seen (all p < 0.001). The median (IQR) CD4% at 96 weeks was 25 (18-30)%. Eighty-nine percent of children had immune recovery (CD4%≥25%) and 75% of children had HIV-RNA <1.7log₁₀copies/ml.</p> <p>Thirty five (32.7%) children experienced VF within 96 weeks. Of these, 24 (68.6%) and 31 (88.6%) children had VF in the first 24 and 48 weeks respectively.</p> <p>Only 1 (0.9%) child experienced IF within 96 weeks and the sensitivity (95%CI) of IF to VF was 4 (0.1-20.4)% and specificity was 100 (93.9-100)%.</p> <p>Conclusion</p> <p>Immunologic failure, as defined here, had low sensitivity compared to VF and should not be recommended to detect treatment failure. Plasma HIV-RNA should be performed twice, at weeks 24 and 48, to detect early treatment failure.</p> <p>Trial Registration</p> <p><b>Clinicaltrials.gov identification number </b><a href="http://www.clinicaltrials.gov/ct2/show/NCT00476606">NCT00476606</a></p

Post-licensure, phase IV, safety study of a live attenuated Japanese encephalitis recombinant vaccine in children in Thailand

AbstractBackgroundJapanese encephalitis is a mosquito-borne viral disease endemic in most countries in Asia. A recombinant live, attenuated Japanese encephalitis virus vaccine, JE-CV, is licensed in 14 countries, including Thailand, for the prevention of Japanese encephalitis in adults and children.MethodsThis was a prospective, phase IV, open-label, multicentre, safety study of JE-CV conducted from November 2013 to April 2015, to evaluate rare serious adverse events (AEs). JE-CV was administered to 10,000 healthy children aged 9months to <5years in Thailand as a primary (Group 1) or booster (Group 2) vaccination. Serious AEs (SAEs), including AEs of special interest, up to 60days after administration were evaluated. Immediate Grade 3 systemic AEs up to 30min after JE-CV administration were also described.ResultsThe median age of participants was 1.1years in Group 1 and 3.8years in Group 2. SAEs were reported in 204 (3.0%) participants in Group 1 and 59 (1.9%) participants in Group 2. Among a total of 294 SAEs in 263 participants, only three events occurring in two participants were considered related to vaccination. All three cases were moderate urticaria, none of which met the definition of AEs of special interest for hypersensitivity. AEs of special interest were reported in 28 (0.4%) participants in Group 1 and 4 (0.1%) participants in Group 2; none were considered related to vaccination. Febrile convulsion was the most frequently reported AE of special interest: 25 (0.4%) participants in Group 1; and 2 (<0.1%) in Group 2. There were no cases of Japanese encephalitis reported. No Grade 3 immediate systemic AEs were reported after any JE-CV vaccination.ConclusionsOur study did not identify any new safety concerns with JE-CV and confirms its good safety profile.This study was registered on www.clinicaltrials.gov (NCT01981967; Universal Trial Number: U1111-1127-7052)

A feasibility study of immediate versus deferred antiretroviral therapy in children with HIV infection

<p>Abstract</p> <p>Objective</p> <p>To evaluate the feasibility of a large immediate versus deferred antiretroviral therapy (ART) study in children.</p> <p>Methods</p> <p>We conducted an open-label pilot randomized clinical trial study in 43 Thai children with CD4 15 to 24% of starting generic AZT/3TC/NVP immediately (Arm 1) or deferring until CD4 < 15% or CDC C (Arm 2). Primary endpoints were recruitment rate, adherence to randomized treatment and retention in trial. Secondary endpoints were % with CDC C or CD4 < 15%. Children were in the trial until the last child reached 108 weeks. Intention to treat and on treatment analyses were performed.</p> <p>Results</p> <p>Recruitment took 15 months. Twenty-six of 69 (37.7%) were not eligible due mainly to low CD4%. Twenty four and 19 were randomized to arms 1 and 2 respectively. All accepted the randomized arm; however, 3 in arm 1 stopped ART and 1 in arm 2 refused to start ART. Ten/19 (53%) in arm 2 started ART. At baseline, median age was 4.8 yrs, CDC A:B were 36:7, median CD4 was 19% and viral load was 4.8 log. All in arm 1 and 17/19 in arm 2 completed the study (median of 134 weeks). No one had AIDS or death. Four in immediate arm had tuberculosis. Once started on ART, deferred arm children achieved similar CD4 and viral load response as the immediate arm. Adverse events were similar between arms. The deferred arm had a 26% ART saving.</p> <p>Conclusion</p> <p>Almost 40% of children were not eligible due mainly to low CD4% but adherence to randomized treatment and retention in trial were excellent. A larger study to evaluate when to start ART is feasible.</p

Extraction of Lead Ions and Partitioning Behaviour in Aqueous Biphasic Systems Based on Polyethylene Glycol and Different Salts

Lead ions are environmental pollutants often present in very low concentrations, which makes them difficult to detect and, thus, present problems for environmental monitoring. In this study, we examined the performance of aqueous biphasic systems based on polyethylene glycol (PEG, molecular mass of 4000 g mol–1) with ammonium sulfate (NH4)2SO4, magnesium sulfate (MgSO4), sodium sulfate (Na2SO4), and trisodium citrate (Na3C6H5O7) for the separation of lead(II) ions from aqueous solutions. We investigated the effects of salt types and the ratio of PEG4000 to salt on the extraction efficiency of lead(II) removal at constant temperatures of 303 K and 0.1 MPa. Additionally, we determined the cloud points (solubility equilibrium curve) and tie-lines for four ternary systems comprising PEG4000, water, and salt (either (NH4)2SO4, MgSO4, Na2SO4, or Na3C6H5O7) under the same conditions. A maximum lead(II) extraction efficiency of 74.4% was achieved using the PEG4000/(NH4)2SO4 system with a mass fraction ratio of PEG4000 to (NH4)2SO4 of 0.2:0.12. This outcome highlights the significant potential of utilizing aqueous biphasic systems based on PEG4000 to separate lead(II) from aqueous solutions efficiently