Continuous Agitation Research Articles

Seawater-softening process through formation of calcite ooids

Conventional water-softening processes usually involve the exchange of Na+ ions for Ca2+ and Mg2+ using commercial or synthesized ion exchangers. The differences in chemical compositions of the ooids can be attributed to the formation in different environments. In this paper, ooid grains form inside assembled semi-pilot softening unit through a continuous chemical process involving reaction between bicarbonate ions and added lime using natural seawater. Our sample of Mediterranean seawater has low Mg2+/Ca2+ ratio (1.98%) within the range chemically favorable for precipitation of low-Mg calcite ooids. Precipitation of calcite occurs around pure quartz sand grains which act as nucleation points (the bed required for sand vessel is 1.65l). The shape of the sand grains controls the overall external morphology of the resulting ooids; they vary in size from 0.5 to 3.0mm and have a high degree of polish due to surface abrasion caused by continuous agitation inside the softening system. Calcite ooid grains (1.53kg) formed within the seawater-softening unit every 18days have many of the ooid features formed in marine environments. Ooids grow to a significant size, at a rate of about 0.17mm of one layer thickness per day inside the softening unit. The average weight percent of calcite precipitate is 35.48% after 18days, at 10°C, 60l/min and pH 9.0. The pellets comprise mainly CaCO3 and SiO2 and some metal ions which may substitute for calcium ions in calcite are present only in trace amounts of the total composition.

BREAKDOWN OF COPPER-SMELTING SLAG BY AMMONIA CHLORIDE

A hydrometallurgical method of copper-smelting slag processing by means of ammonium chloride is proposed. A basic processing diagram has been developed. Investigations of slag decomposition by ammonium chloride are conducted and the recommendations concerning the process implementation are given. Minerals, which form copper-smelting slag, are Fe2SiO4, Zn2SiO4, CuFe2O4 and Ca2SiO4. The decomposition should be carried out at temperature of 280 °C for 4 hours with continuous agitation and at slag/ammonium chloride ratio of 1 : 2.

Evaluation of Silver Nanoparticle Mediated Reduction of Neovascularisation (Angiogenesis) in Chicken Model

Neovascularisation is a key event during the growth of solid tumor and the process is called angiogenesis. Tumor cells demands higher oxygen and their glucose requirement is also higher than normal cells, and during the growth of solid tumor new blood vessels also arise rapidly to fulfil the raised requirement of nutrients. Hence targeting the formation of new blood vessel formation leading to deprived nutrition and oxygen supply will lead to inhibited growth of tumor. In the present study, silver nanoparticles were manufactured by green synthesis using Azadirachta indica (neem) leaves and its effect on process of neovascularisation was evaluated. Bioconversion from silver nitrate solution to silver nanoparticles included addition of AgNO 3 (1mM) to fresh leaf broth of Neem and the conversion was allowed to take place for 4 hrs. with continuous agitation at 80 rpm. Formation of silver (Ag) nanoparticle was visualised by change in colour from pale yellow to dark brown. Nanoparticles when subjected to developing embry- onated eggs of chicken were found to reduce the number of viable blood vessels with reduction in number of vessel branch points in chorioallantoic membrane leading to the death of embryo. Silver nanoparticles prepared through bioconversion in the study, successfully reduced angiogenesis in embryonated chicken model and this anti-angiogenic property of Ag nanoparticles, can be explored as a potential therapeutic against pathological angiogenesis and solid tumors by targeting the vasculature.

Controlled and sustained release of pharmaceuticals via single step solvent-free encapsulation.

Herein, we report a novel and solvent-free technique for the encapsulation of pharmaceuticals that allows achieving controllable release rates. This method utilizes the deposition of a plasma polymer coating of controlled chemistry and thickness on the outer surface of drug particles placed under continuous agitation.

A simple and easy in vitro model to test the efficacy of IV lines' needleless connectors against contamination.

BackgroundHub colonization after manipulation is responsible for 29% to 60% of catheter-related bloodstream infections (C-RBSI). Prevention can be achieved by the use of hub connectors, but its efficacy is generally based on instillation of high concentrations of microorganisms, which do not reflect the real contamination in daily practice. Our purpose was to create an in vitro model lasting long enough to be used for the comparison of the efficacy between various connectors against contamination simulating the real daily handling.MethodsThe model consisted of 40 blood culture bottles with an inserted cannula with a needle-free closed connector. Twice a day, each line was manipulated while instilling 1 mL of two different fluids (saline and propofol). We manipulated the bottles as follows: ten bottles with clean gloves and disinfecting connectors with alcohol (controls), ten bottles with hands (no gloves), ten bottles with gloves impregnated with a 0.5 McFarland (MF) solution of Staphylococcus aureus (SA), and ten bottles with gloves impregnated with a 0.05 MF solution of SA. The bottles were incubated in a BACTEC System at 37°C under continuous agitation up to 10 days. When a bottle turned positive, 100 μL of the fluid was cultured and incubated followed by microorganism identification using standard procedures.ResultsOverall, all bottles in the control group were negative at the end of the incubation time. In the three contamination experiments, almost all (38/40) bottles were positive during the incubation time. We only found differences regarding the median time to positivity (interquartile range (IQR)) between saline and propofol in the manipulation with SA 0.05 MF: 240 h (154.82 to 360.00) vs. 66 h (58.01 to 69.11), p = 0.008.ConclusionsA daily connector handling with 0.05 McFarland S. aureus solution while instilling saline proved to be a useful model lasting long enough to be used for the comparison of the efficacy of different types of closed needleless connectors against contamination.Electronic supplementary materialThe online version of this article (doi:10.1186/s40635-014-0027-9) contains supplementary material, which is available to authorized users.

Combined pulsing currents and agitation for electrodeposition

In order to exploit the full potential of current pulsing one may need to combine it with synchronised and pulsing solution agitation. The problem with providing pulsing agitation is that changes in the momentum boundary layer have a much larger time constant than that required for changing reaction conditions at the electrode surface. One agitation scheme which may not have this limitation is ultrasonication. Ultrasonic (US) transducers respond to pulsing electrical signals which can be switched within a second. In industrial tank systems the transducers are loaded on the wall of a tank, which allows the agitation to be transferred into the electrolyte immediately. In the current work, the effect of continuous vs pulse US agitation on metal deposition under mass transfer limitations has been examined. In order to test the applicability of this concept, copper has been deposited at a cathode which is separated from the anode by a gap of 0·3 mm using direct current and pulsing current deposition under silent and ultrasonic agitation conditions. The cell potential has been monitored to determine the stability of the process. Deposit roughness was determined as a test of process performance. To the authors’ knowledge, this work provides the first assessment of combining these two different pulsing parameters for electrodeposition.

In vitro evaluation of platelet concentrates suspended in additive solution and treated for pathogen reduction: effects of clumping formation.

Platelet concentrates may demonstrate visual, macroscopic clumps immediately after collection following aphaeresis or production from whole blood, independently of the preparation method or equipment used. The relationship between the occurrence of clumping and their effect on in vitro quality of platelets was investigated. Platelet concentrates, suspended in SSP+ additive solution (Macopharma), were obtained by automated processing and also from routine processing. A total of twelve units were allocated to the test group (n=12) due to the presence of clumps. Platelet concentrates without clumps were used as controls (n=10). All platelet units were treated for pathogen reduction following storage under continuous agitation for in vitro testing over a 9-day storage period. No significant differences were found throughout storage between the groups. The lactate dehydrogenase levels increased in both groups; this increase was higher in the test group on the last day of testing, without there being a significant difference on day 2. In contrast, pH values on day 2 were significantly different between the test and control groups. Platelet-derived cytokines increased comparably during storage. The results confirm good in vitro quality and storage stability of platelets suspended in SSP+ and treated with the Intercept pathogen reduction system. The presence of "non-compacted" clumps in platelet concentrates does not appear to affect the in vitro quality of the platelets.

English

An efficient protocol had been developed for the root culture of Luffa acutangula (L.) Roxb. The root and leaf explants from 21 day old in vitro raised seedlings were cultured on half strength Murashige and Skoog (MS) medium supplemented with different concentrations and combinations of Indole-3-acetic acid(IAA), Indole-3-butyric acid (IBA) and Napthalene acetic acid (NAA). IBA at 1.0 mgl-1 combined with NAA (1.0 mgl-1) induced maximum percentage of rooting from leaf explants, under total dark condition. After 3 weeks, well established roots were separated. Fresh root tissue from the leaf explants and root tips from in vitro seedlings were subcultured in half strength MS liquid medium supplemented with different concentrations and combinations of IAA, IBA and NAA, under continuous agitation at 80 rpm under total dark condition. The biomass of root culture (derived from leaf explants) in the MS medium fortified with IBA(1.0 mgl-1), NAA(1.0mgl-1) and L-glutamine (20 mgl-1) was increased to 5.38 g FW and the biomass of root culture (derived from root tip) in the MS medium supplemented with IBA (0.5 mgl-1), NAA (1.0 mgl-1) and L- glutamine (20 mgl-1) was increased to 5.82 g FW after 7 weeks of culture.

Anode effect and МHD-instability in aluminium electrolyzer. Control of parameters for their prognosis

The results of studying the interaction of the complex of process parameters on the occurrence and course of the "anode effect", using which will allow to significantly improve the electrolysis process and increase the electrolyzer efficiency were presented. With the appearance of the "anode effect", the current density on the free surface greatly is increased, the anode potential becomes more positive and is passivated to the potential, sufficient for the discharge of fluorine ions, fluorine ions with oxygen ions at the anode start to be discharged, the concentration of perfluorocarbons increases up to 30%. Interaction of the magnetic field with the current appears not only in the misalignment of the molten metal surface. The studies of magnetohydrodynamic processes in the electrolyzer have shown that the molten metal surface is in a state of continuous agitation and herewith the wave height can reach 45 mm. Thus, the wave height is comparable to the interpolar distance, which causes local short-circuiting.To minimize the number of process abnormalities on the electrolyzer, the necessity of constant monitoring of a number of parameters that characterize the current state and development of abnormalities in the bath: temperature of the electrolyte and its overheating; concentration of alumina; composition of the anode gas and the ratio of CF4, CO, CO2 in flue gases; back EMF and the specific resistivity of the electrolyte; interpolar distance, height of the metal and electrolyte; ratio of the melt densities of the electrolyte and aluminum; thickness of the ledge; effective current density and its distribution under the anode face; distribution of current intensity and magnetic field in hearth; change in the shape of the working space was established.

Properties of low temperature belite cements made from aluminosilicate wastes by hydrothermal method

The aim of this study is the synthesis at low temperature (1000°C) of reactive belite cement, rich in reactive C2S phases (α′L and/or β-C2S), starting from aluminosilicate wastes (oil well drilling mud and hydraulic dam sludge) and hydraulic lime dust recovered from bagging workshops. A hydrothermal treatment of the raw cement mixture was performed in an alkaline solution of KOH (0.6M), with heating at 100°C for 4h under atmospheric pressure and continuous agitation. The burning of the hydrothermal mixture at 1000°C produced reactive belite cements containing between 79% and 86% of C2S (α′L and/or β polymorphs), the rest being C12A7 (5–8%), C4AF (7–11%) and free lime (2%). The cements were characterized by X-ray Fluorescence (XRF), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), microprobe, and laser granulometry. The hardening evolution of belite cement pastes and mortars was followed by thermo-gravimetric analysis (TGA), setting time and compressive strength. The results showed a rapid production of hydrates (C–S–H/C–A–S–H, calcium aluminate hydrates and portlandite), with a fast setting time (reaction of C12A7) and compressive strength evolution that led to these cements being classified in the 32.5 category according to EN 197-1.

Production, optimization and partial purification of protease from Bacillus subtilis

Proteases have characteristics of biotechnological interest and have thus become important industrial enzymes. We report the production of thermostable protease and its characterization in Bacillus species, which is a thermotolerant bacterium; Bacillus subtilis is widely used for isolating protease enzyme. Gelatin was used as the substrate in nutrient agar medium for screening and showed the maximum zone of activity (22mm) after overnight incubation and addition of the indicator. Under submerged fermentation conditions, a high level of protease production was found at 45°C after 36h at pH 10, with continuous agitation (180rpm). The presence of galactose and peptone in the medium enhanced enzyme production by 0.5% when compared with other carbon and nitrogen sources. Thus, such additions can augment protease production and their application in various industries.

An optimized protocol for isolating primary epithelial cell chromatin for ChIP.

A critical part of generating robust chromatin immunoprecipitation (ChIP) data is the optimization of chromatin purification and size selection. This is particularly important when ChIP is combined with next-generation sequencing (ChIP-seq) to identify targets of DNA-binding proteins, genome-wide. Current protocols refined by the ENCODE consortium generally use a two-step cell lysis procedure that is applicable to a wide variety of cell types. However, the isolation and size selection of chromatin from primary human epithelial cells may often be particularly challenging. These cells tend to form sheets of formaldehyde cross-linked material in which cells are resistant to membrane lysis, nuclei are not released and subsequent sonication produces extensive high molecular weight contamination. Here we describe an optimized protocol to prepare high quality ChIP-grade chromatin from primary human bronchial epithelial cells. The ENCODE protocol was used as a starting point to which we added the following key steps to separate the sheets of formaldehyde-fixed cells prior to lysis. (1) Incubation of the formaldehyde-fixed adherent cells in Trypsin-EDTA (0.25% room temperature) for no longer than 5 min. (2) Equilibration of the fixed cells in detergent-free lysis buffers prior to each lysis step. (3) The addition of 0.5% Triton X-100 to the complete cell membrane lysis buffer. (4) Passing the cell suspension (in complete cell membrane lysis buffer) through a 25-gauge needle followed by continuous agitation on ice for 35 min. Each step of the modified protocol was documented by light microscopy using the Methyl Green-Pyronin dual dye, which stains cytoplasm red (Pyronin) and the nuclei grey-blue (Methyl green). This modified method is reproducibly effective at producing high quality sheared chromatin for ChIP and is equally applicable to other epithelial cell types.

Addition of sialidase or p38 MAPK inhibitors does not ameliorate decrements in platelet in vitro storage properties caused by 4°C storage.

Bacterial proliferation is inhibited in platelets (PLTs) stored at refrigerated temperatures, but also dramatically decreases PLT in vivo survival. Recent studies have demonstrated that cold temperature (CT) stored PLTs secrete sialidases upon re-warming, removing sialic acid from the PLT surface, which may be responsible for clustering of GPIbα and PLT clearance from circulation. In this study, the influence of a sialidase inhibitor or a p38 MAP kinase inhibitor was evaluated in units stored at 4°C. After collection of a single Trima apheresis unit (n=12), PLTs were aliquoted into four 60-ml CLX storage bags. One bag was stored at 20-24°C (RT) with continuous agitation; a second bag was stored at 4°C without agitation; a third bag was held at 4°C without agitation with sialidase inhibitor, a fourth bag was incubated at 4°C with a p38 MAPK inhibitor without agitation. Beginning from Day 1, all in vitro PLT parameters were adversely affected by CT compared to those of RT. Similar in vitro storage properties were observed in CT PLT in the presence or absence of sialidase or p38 MAPK inhibitors. P38 MAPK phosphorylation inhibition was not observed at CT. Decrease of sialidase activity was observed for 2days in PLTs stored in additive solution but not in plasma. Addition of either sialidase or p38 MAPK inhibitors do not improve any in vitro parameters of PLTs stored at 4°C in 100% plasma.

An intermittent rocking platform for integrated expansion and differentiation of human pluripotent stem cells to cardiomyocytes in suspended microcarrier cultures

The development of novel platforms for large scale production of human embryonic stem cells (hESC) derived cardiomyocytes (CM) becomes more crucial as the demand for CMs in preclinical trials, high throughput cardio toxicity assays and future regenerative therapeutics rises. To this end, we have designed a microcarrier (MC) suspension agitated platform that integrates pluripotent hESC expansion followed by CM differentiation in a continuous, homogenous process.Hydrodynamic shear stresses applied during the hESC expansion and CM differentiation steps drastically reduced the capability of the cells to differentiate into CMs. Applying vigorous stirring during pluripotent hESC expansion on Cytodex 1 MC in spinner cultures resulted in low CM yields in the following differentiation step (cardiac troponin-T (cTnT): 22.83±2.56%; myosin heavy chain (MHC): 19.30±5.31%). Whereas the lower shear experienced in side to side rocker (wave type) platform resulted in higher CM yields (cTNT: 47.50±7.35%; MHC: 42.85±2.64%). The efficiency of CM differentiation is also affected by the hydrodynamic shear stress applied during the first 3days of the differentiation stage. Even low shear applied continuously by side to side rocker agitation resulted in very low CM differentiation efficiency (cTnT<5%; MHC<2%). Simply by applying intermittent agitation during these 3days followed by continuous agitation for the subsequent 9days, CM differentiation efficiency can be substantially increased (cTNT: 65.73±10.73%; MHC: 59.73±9.17%). These yields are 38.3% and 39.3% higher (for cTnT and MHC respectively) than static culture control.During the hESC expansion phase, cells grew on continuously agitated rocker platform as pluripotent cell/MC aggregates (166±88×105μm2) achieving a cell concentration of 3.74±0.55×106cells/mL (18.89±2.82 fold expansion) in 7days. These aggregates were further differentiated into CMs using a WNT modulation differentiation protocol for the subsequent 12days on a rocking platform with an intermittent agitation regime during the first 3days. Collectively, the integrated MC rocker platform produced 190.5±58.8×106 CMs per run (31.75±9.74 CM/hESC seeded). The robustness of the system was demonstrated by using 2 cells lines, hESC (HES-3) and human induced pluripotent stem cell (hiPSC) IMR-90. The CM/MC aggregates formed extensive sarcomeres that exhibited cross-striations confirming cardiac ontogeny. Functionality of the CMs was demonstrated by monitoring the effect of inotropic drug, Isoproterenol on beating frequency.In conclusion, we have developed a simple robust and scalable platform that integrates both hESC expansion and CM differentiation in one unit process which is capable of meeting the need for large amounts of CMs.

A simple cost-effective manometric respirometer: design and application in wastewater biomonitoring

Application of respirometric tools in wastewater engineering fields is still not getting familiarity and acceptance by academy or industry in developing countries as compared to the use of conventional biochemical oxygen demand (BOD) approach. To justify the applicability of respirometry, a low-cost respirometric device suitable for monitoring biodegradation process in wastewater has been developed. This device contains six independently operating reactors placed in a temperature control unit for the bioassay of five wastewater samples simultaneously (along with one blank). Each reactor is equipped with a magnetic stirrer for the continuous agitation of the test sample. Six manometers, linked with the individual reactors, measure the pressure and volume changes in the headspace gas phase of the reactor. Working formulae have been derived to convert the ‘volume-change in gas phase’ data to ‘the oxygen depletion in the whole liquid–gas system’ data. The performance of the device has been tested with glucose–glutamic acid standard solution and found satisfactory. Conventional BOD test and the respirometric measurements were performed simultaneously and it is found that in addition to measuring the BOD of the sample, this device gives oxygen uptake profile for further analysis to determine the biokinetic coefficients. Additionally, in some cases, following a specific test protocol, the respirometer can indirectly estimate the carbon dioxide evolved during biodegradation process for calculating respiratory activity parameter such as respiratory quotient. It is concluded that the device can be used in the laboratories associated with the activated sludge plants and also for teaching and research purposes in developing countries.

The Effect of (Non-) Agitating Condition on Agonist Induced-Aggregation of the 48 hours-Stored Platelet Concentrates

Platelets (PLTs) transfusion and their efficacy in a recipient depend on PLTs quality and quantity pretransfusion. One of the important aspects of treating PLT concentrates (PCs), which has controversial effect on functionality is storage of the PCs in an active metabolic state during prolonged storage either by (gentle-) agitation or by rotations in the different angels. Study design and Methods: The amount of PCs obtained through double centrifugation methods, as described. We measured ADP, Collagen and ristocetin-induced aggregation after 48 hours of storage in PC kept under continuous agitation (CA6h), and in those in which agitation was stopped in the last 6 hours i.e Without Continuous Agitation for 6 Hours (WCA6h). Results: In Timori et al. BT 201 we have shown that an interruption of 6 hours on PCs has no deleterious effect on PCs P-selectin, PF4, LDH release, pH, swirling, and count. In this study we focus more in details about different agonist induced-aggregation functions, and their receptors’ (ir-) responsiveness and (de-)sensitivity, signal transduction pathways, of the WCA6h and CA6h stored counterparts. The mean level of aggregation response to collagen, ADP and ristocetin in agitated CA6h versus WCA6hr were 3.49 ± 1.73% vs. 3.46 ± 1.0% (p< 0.962), 4.30 ± 2.7% vs. 3.20 ± 3.9% (p< 0.518), and 79.2 ± 4.4% vs. 66.65 ± 28.55% (p<0.186), respectively. Discussion: We observed no significant differences between different receptors affected by interruption to respond for firmed aggregates. Thus, a short period of 6 hours non-agitating condition after 42 hours continue agitation in the permeable bags had not deleterious effect on PCs agonist-induced aggregation. Compared to disrupted, continue agitation has no superior effect on old PCs’(ir-) responsiveness and (de-)sensitivity after 48 hours.

Production and biochemical characterization of a high maltotetraose (G4) producing amylase from Pseudomonas stutzeri AS22.

Amylase production and biochemical characterization of the crude enzyme preparation from Pseudomonas stutzeri AS22 were evaluated. The highest α-amylase production was achieved after 24 hours of incubation in a culture medium containing 10 g/L potato starch and 5 g/L yeast extract, with initial pH 8.0 at 30°C under continuous agitation at 200 rpm. The optimum temperature and pH for the crude α-amylase activity were 60°C and 8.0, respectively. The effect of different salts was evaluated and it was found that both α-amylase production and activity were Ca2+-dependent. The amylolytic preparation was found to catalyze exceptionally the formation of very high levels of maltotetraose from starch (98%, w/w) in the complete absence of glucose since the initial stages of starch hydrolysis (15 min) and hence would have a potential application in the manufacturing of maltotetraose syrups.

DEALING WITH OUR APATHY THROUGH THE RADIO: ANALYSIS OF THE ROLE OF FRCN NNoKO UMUNWANYI PROGRAMME IN INFLUENCING WOMEN TO PARTICIPATE IN POLITICS

The last three decades has been dotted by the continuous agitation by women for equal political positions in the political space of Nigeria. While women advocacy groups and international organisations accuse the men folk of engineering a political architecture that makes it difficult for women to participate, the men believe that there is growing apathy on the part of women. This has brought to the fore the issue of 35 percent affirmative action for women in developing societies like Nigeria. But this can only be achieved by raising the awareness level and interest of women in politics. In line with this demand, the Federal Radio Corporation of Nigeria (FRCN) Enugu developed a gender political programme- Nn?ko Umunwanyi. The programme which is only targeted at women of Igbo speaking origin in Enugu State, is design to raise the interest of rural women in politics. More than ten years after this programme was designed and broadcast to rural women in Enugu State, how far has it gone in raising the awareness, knowledge level and interest of women in politics? In investigating all these, the researcher used Explanatory Sequential mixed methods design developed by Cresswell (2012) to collect both quantitative and qualitative data. Questionnaire was used to collect quantitative data while focus group discussion was used to generate qualitative data. After a thorough analysis using both quantitative and qualitative data, findings showed that women in Enugu State are exposed to Nn?ko Umunwanyi. programme to a large extent. It was equally found that the knowledge and women participation in politics have increased as a result of their exposure in the programme. Based on these, it was recommended that more programmes of this nature should be designed. Keyword: World? FRCN? Politics ?Marginalization ?Awareness ?Knowledge ?Participation

Evaluation of in vitro storage properties of apheresis platelets suspended in a bicarbonate‐containing additive solution with low levels of plasma and stored with a 24‐hour interruption of agitation

PLT additive solutions (PAS) are useful for reducing the frequency and/or severity of plasma-associated transfusion reactions. A new PAS solution, PAS-5, containing 5% plasma, maintains in vitro PLT properties during 7-day storage. Periods with interruption of agitation (IA) ≤24h routinely occur during PLT shipment and do not usually compromise platelet quality. The aim of the study was to evaluate the properties of PLTs stored for 7days in 95% PAS-5/5% plasma subjected to a 24-h IA. Double apheresis Amicus units (n=12) were collected using a manual PAS-5 addition to hyperconcentrated PLTs. PLT units were equally divided in two containers. Control and test PLTs were stored with continuous agitation at 20-24°C except for 24-h IA period for test units between days 2-3. During storage, levels of glucose, lactate, mitochondrial membrane potential and aggregation significantly differed in test units compared to those of control. The pH levels of test PLTs were less than those of control units with 7/12 test units having pHs <6·2 on Day 7 compared to 1/12 control units. Morphology score, GP1bα expression, ESC values, superoxide production were also less, and activation was greater in test PLTs than those of control. All other parameters were similar between test and control units. PLTs stored in PAS-5 solution containing 5% plasma with a 24-h IA results in marked decrements in many in vitro PLT quality parameters during 7-day storage.

Effect of Degree of Substitution on the Adhesive Propterties of Methyl Cellulose Derived from Waste Bitter Orange [Citrus Aurantium (Linn.)] Mesocarp

Cellulose was extracted from waste bitter orange mesocarp and chemically modified by etherification in propan-2-ol as solvent with varying amount of methyl chloride and the degree of substitution (DS) of the methyl group for H of the native cellulose calculated by acid-base titration. Nine pastes (seven etherified cellulose (methyl cellulose) and the native cellulose (control) were prepared by dispersing them in distilled water (35% w/v) and heating the eight dispersions to 45°C with continuous agitation for 15min. The solutions were then cooled to room temperature and allowed to gel. The effect of DS on the adhesive properties of the pastes (tack strength, rolling ball test, gelation time, drying time, optical clarity, relative viscosity, syneresis) was comparatively investigated. The results showed that the DS in the etherified cellulose ranged from 1.31 to 1.98 with the methyl cellulose giving higher values of viscosity and tack strength with increase in DS. However, lower values of syneresis, gelation time, optical clarity, drying time and rolling ball distance were recorded with increase in DS. Increase in desirable adhesive properties of the methyl cellulose is attributed to its relatively higher molecular weight compared to the native cellulose. Production and use of etherified cellulose, in place of petroleum-based synthetic adhesives, in remoistening applications such as envelope flaps, postage stamps, labels and other paper works in Nigeria and other developing economies is recommended from the viewpoints of economy, environment, health and safety. DOI: 10.5901/ajis.2013.v2n13p19