bluuebunny/crossref_metadata_2025 huggingface dataset:
Anti-human immunodeficiency virus type 1 agent alpha-hydroxy glycineamide enters the target cells via a mechanism of passive diffusion
Authors: Youssefi Masoud , Vahlne Anders
Published: April 2014

Objectives

Alpha-hydroxy glycineamide (αHGA) is the active antiviral metabolite of tri-peptide glycyl-prolyl-glycine-amide (GPG-NH2). αHGA inhibits the replication of HIV-1 in vitro by interfering with the capsid formation. It has also an effect on viral gp160 envelope protein. Since drug transport is an important aspect of drug function, we investigated the mechanism of [14C] αHGA uptake by a human T cell line.

Methods

H9 cells were incubated with defined amounts of radiolabelled αHGA for definite time durations. After harvesting the cells and removal of radiolabelled material, the radioactivity associated with the cells was assayed. Experiments were also designed to address the effect of metabolic inhibitors, temperature and extra unlabelled compound as potential competitor on the cellular uptake of αHGA.

Key findings

Uptake of αHGA into H9 cells was time- and dose-dependent. The uptake properties showed a low temperature dependency (Q10 < 2). Moreover the uptake was not inhibited by increasing concentrations of cold competitors. There was no effect on cellular uptake of αHGA by known metabolic inhibitors, NaN3 and NaF.

Conclusions

Kinetic analysis of compound uptake, metabolic inhibition studies, saturation studies and the Q10 value of αHGA uptake indicate that the compound enters H9 cells by a mechanism of passive diffusion.
Lymphocytic ganglioneuritis secondary to intervertebral disc extrusion in a dog
Authors: Mouradian‐Darby A. E. , Young B. D. , Griffin J. F. , Mansell J. , Levine J. M.
Published: April 2014

This study presents a case of lymphocytic ganglioneuritis in a dog secondary to intervertebral disc extrusion that mimicked a peripheral nerve sheath tumour on magnetic resonance imaging. A four‐year‐old spayed female dachshund with lumbar pain was imaged via magnetic resonance. A tubular, space‐occupying, contrast‐enhancing lesion was noted in the right intervertebral foramen at L6 to L7. This was presumed to represent focal enlargement of the right sixth lumbar spinal nerve. A right‐sided haemilaminectomy was performed at L6 to L7 and material that grossly resembled extruded nucleus pulposus was removed. The right L6 dorsal root ganglion, dorsal nerve root and proximal spinal nerve were severely enlarged and a partial thickness biopsy was collected from the dorsal root ganglion. Results of histopathological examination of the submitted tissue samples were consistent with extruded disc material and lymphocytic ganglioneuritis. To the author's knowledge, this is the first published report of lymphocytic ganglioneuritis secondary to intervertebral disc disease in a dog.
Gall bladder rupture associated with cholecystitis in a domestic ferret (Mustela putorius)
Authors: Huynh M. , Guillaumot P. , Hernandez J. , Ragetly G.
Published: April 2014

A six‐year‐old neutered female albino ferret was presented with an acute episode of lethargy and anorexia. Clinical examination revealed marked cranial abdominal pain. A severe neutrophilic leukocytosis was present. Abdominal ultrasound was consistent with a diffuse peritonitis and severe bile duct inflammation. Cytology of the abdominal effusion revealed bile peritonitis. An exploratory laparotomy was performed and the gall bladder appeared inflamed with multiple perforations. A cholecystectomy was performed. The ferret recovered without complication. Bacteriological culture of the bile and gall bladder yielded a pure growth of Pseudomonas aeruginosa. Histopathological analysis of the gall bladder and liver was consistent with a marked cholecystitis and cholangiohepatitis. On the basis of sensitivity testing, the ferret was treated with marbofloxacin for one month. No complications or reoccurrence were seen up to 1 year after the diagnosis. To the author's knowledge, this is the first report of bile peritonitis secondary to gall bladder rupture in a ferret.
A simple and inexpensive point‐of‐care test for hepatitis B surface antigen detection: serological and molecular evaluation
Authors: Gish R. G. , Gutierrez J. A. , Navarro‐Cazarez N. , Giang K. , Adler D. , Tran B. , Locarnini S. , Hammond R. , Bowden S.
Published: April 2014

Early identification of chronic hepatitis B is important for optimal disease management and prevention of transmission. Cost and lack of access to commercial hepatitis B surface antigen (HBsAg) immunoassays can compromise the effectiveness of HBV screening in resource‐limited settings and among marginalized populations. High‐quality point‐of‐care (POC) testing may improve HBV diagnosis in these situations. Currently available POC HBsAg assays are often limited in sensitivity. We evaluated the NanoSign® HBs POC chromatographic immunoassay for its ability to detect HBsAg of different genotypes and with substitutions in the ‘a’ determinant. Thirty‐seven serum samples from patients with HBV infection, covering HBV genotypes A–G, were assessed for HBsAg titre with the Roche Elecsys HBsAg II quantification assay and with the POC assay. The POC assay reliably detected HBsAg at a concentration of at least 50 IU/mL for all genotypes, and at lower concentrations for some genotypes. Eight samples with substitutions in the HBV ‘a’ determinant were reliably detected after a 1/100 dilution. The POC strips were used to screen serum samples from 297 individuals at risk for HBV in local clinical settings (health fairs and outreach events) in parallel with commercial laboratory HBsAg testing (Quest Diagnostics EIA). POC testing was 73.7% sensitive and 97.8% specific for detection of HBsAg. Although the POC test demonstrated high sensitivity over a range of genotypes, false negatives were frequent in a clinical setting. Nevertheless, the POC assay offers advantages for testing in both developed and resource‐limited countries due to its low cost (0.50$) and immediately available results.
Cue Reliance in L2 Written Production
Authors: Wiechmann Daniel , Kerz Elma
Published: April 2014

Second language learners reach expert levels in relative cue weighting only gradually. On the basis of ensemble machine learning models fit to naturalistic written productions of German advanced learners of English and expert writers, we set out to reverse engineer differences in the weighting of multiple cues in a clause linearization problem. We found that, while German advanced learners succeeded in identifying important cues, their assignment of cue importance differed from that of the expert control group. Even at advanced levels, learners are found to rely on a smaller set of perceptually salient cues than native speakers do, focusing on cues that exhibit relatively high cue availability and relatively low cue reliability. Our findings suggest that the principles of the Unified Model of first and second language acquisition, which have been extensively supported for comprehension also underlie the written production of advanced second language learners.
EnhancingTax Compliance through Coercive and Legitimate Power ofTax Authorities by Concurrently Diminishing or Facilitating Trust inTax Authorities
Authors: Hofmann Eva , Gangl Katharina , Kirchler Erich , Stark Jennifer
Published: April 2014

Both coercion, such as strict auditing and the use of fines, and legitimate procedures, such as assistance by tax authorities, are often discussed as means of enhancing tax compliance. However, the psychological mechanisms that determine the effectiveness of each strategy are not clear. Although highly relevant, there is rare empirical literature examining the effects of both strategies applied in combination. It is assumed that coercion decreases implicit trust in tax authorities, leading to the perception of a hostile antagonistic tax climate and enforced tax compliance. Conversely, it is suggested that legitimate power increases reason‐based trust in the tax authorities, leading to the perception of a service climate and eventually to voluntary cooperation. The combination of both strategies is assumed to cause greater levels of intended compliance than each strategy alone. We conducted two experimental studies with convenience samples of 261 taxpayers overall. The studies describe tax authorities as having low or high coercive power (e.g., imposing lenient or severe sanctions) and/or low or high legitimate power (e.g., having nontransparent or transparent procedures). Data analyses provide supportive evidence for the assumptions regarding the impact on intended tax compliance. Coercive power did not reduce implicit trust in tax authorities; however, it had an effect on reason‐based trust, interaction climate, and intended tax compliance if applied solely. When wielded in combination with legitimate power, it had no effect.
The High Court of the People: Popular Constitutionalism inHongKong underChinese Sovereignty
Authors: Ip Eric C.
Published: April 2014

Popular constitutionalism rarely arises in authoritarian polities. In the absence of genuine elections and referenda, aggrieved and disenfranchised citizens are more likely to resort to extraconstitutional action to defend themselves, to which the regime may respond with decisive suppression. Systemic popular constitutionalism did emerge inHongKong, currently underChinese sovereignty, however. Through coordinated mass resistance based on shared constitutional understandings, large numbers of residents have succeeded in restraining the appointedHongKong chief executive from deploying his full range of powers, obligedChina to make concessions on electoral reform it would not have made otherwise, and enabled the Basic Law, an imposed constitution, to remain relevant. This article specifies three preconditions under which the residents ofHongKong have, in the teeth of authoritarianism, managed to adjudge the constitutionality of the acts of the ruling elite with their feet. These preconditions, nevertheless, are idiosyncratic, and may not endure the recent mounting tensions betweenHongKong andChina [Correction added on 5 June 2014, after first online publication: the phrase “to authoritarian politic” has been removed from the last statement in the abstract.].
A strongly hydrated microclast in the Rumuruti chondrite NWA 6828: Implications for the distribution of hydrous material in the solar system
Authors: Greshake Ansgar
Published: April 2014

Hydrous carbonaceous microclasts are by far the most abundant foreign fragments in stony meteorites and mostly resemble CI1‐, CM2‐, or CR2‐like material. Their occurrence is of great importance for understanding the distribution and migration of water‐bearing volatile‐rich matter in the solar system. This paper reports the first finding of a strongly hydrated microclast in a Rumuruti chondrite. The R3‐6 chondrite Northwest Africa 6828 contains a 420 × 325 μm sized angular foreign fragment exhibiting sharp boundaries to the surrounding R‐type matrix. The clast is dominantly composed of magnetite, pyrrhotite, rare Ca‐carbonate, and very rare Mg‐rich olivine set in an abundant fine‐grained phyllosilicate‐rich matrix. Phyllosilicates are serpentine and saponite. One region of the clast is dominated by forsteritic olivine (Fa<2) supported by a network of interstitial Ca‐carbonate. The clast is crosscut by Ca‐carbonate‐filled veins and lacks any chondrules, calcium‐aluminum‐rich inclusions, or their respective pseudomorphs. The hydrous clast contains also a single grain of the very rare phosphide andreyivanovite. Comparison with CI1, CM2, and CR2 chondrites as well as with the ungrouped C2 chondrite Tagish Lake shows no positive match with any of these types of meteorites. The clast may, thus, either represent a fragment of an unsampled lithology of the hydrous carbonaceous chondrite parent asteroids or constitute a sample from an as yet unknown parent body, maybe even a comet. Rumuruti chondrites are a unique group of highly oxidized meteorites that probably accreted at a heliocentric distance >1 AU between the formation regions of ordinary and carbonaceous chondrites. The occurrence of a hydrous microclast in an R chondrite attests to the presence of such material also in this region at least at some point in time and documents the wide distribution of water‐bearing (possibly zodiacal cloud) material in the solar system.
Contrasting genetic diversity patterns in two sister kelp species co‐distributed along the coast of Brittany, France
Authors: Robuchon Marine , Le Gall Line , Mauger Stéphane , Valero Myriam
Published: April 2014

We investigated patterns of genetic structure in two sister kelp species to explore how distribution width along the shore, zonation, latitudinal distribution and historical factors contribute to contrasting patterns of genetic diversity. We implemented a hierarchical sampling scheme to compare patterns of genetic diversity and structure in these two kelp species co‐distributed along the coasts of Brittany (France) using a total of 12 microsatellites, nine for Laminaria hyperborea and 11 for Laminaria digitata, of which eight amplified in both species. The genetic diversity and connectivity of L. hyperborea populations were greater than those of L. digitata populations in accordance with the larger cross‐shore distribution width along the coast and the greater depth occupied by L. hyperborea populations in contrast to L. digitata populations. In addition, marginal populations showed reduced genetic diversity and connectivity, which erased isolation‐by‐distance patterns in both species. As L. digitata encounters its southern range limit in southern Brittany (SBr) while L. hyperborea extends down to mid‐Portugal, it was possible to distinguish the effect of habitat continuity from range edge effects. We found that L. digitata did not harbour high regional diversity at its southern edge, as expected in a typical rear edge, suggesting that refuges from the last glacial maximum for L. digitata were probably not located in SBr, but most likely further north. For both species, the highest levels of genetic diversity were found in the Iroise Sea and Morlaix Bay, the two regions in which they are being currently harvested. Preserving genetic diversity of these two foundation species in these areas should, thus, be a priority for the management of this resource in Brittany.
Evolutionary basis of mitonuclear discordance between sister species of mole salamanders (Ambystoma sp.)
Authors: Denton Robert D. , Kenyon Laura J. , Greenwald Katherine R. , Gibbs H.Lisle
Published: April 2014

Distinct genetic markers should show similar patterns of differentiation between species reflecting their common evolutionary histories, yet there are increasing examples of differences in the biogeographic distribution of species‐specific nuclear (nuDNA) and mitochondrial DNA (mtDNA) variants within and between species. Identifying the evolutionary processes that underlie these anomalous patterns of genetic differentiation is an important goal. Here, we analyse the putative mitonuclear discordance observed between sister species of mole salamanders (Ambystoma barbouri and A. texanum) in which A. barbouri‐specific mtDNA is found in animals located within the range of A. texanum. We test three hypotheses for this discordance (undetected range expansion, mtDNA introgression, and hybridization) using nuDNA and mtDNA data analysed with methods that varied in the parameters estimated and the timescales measured. Results from a Bayesian clustering technique (structure), bidirectional estimates of gene flow (migrate‐n and IMa2) and phylogeny‐based methods (*beast, bucky) all support the conclusion that the discordance is due to geographically restricted mtDNA introgression from A. barbouri into A. texanum. Limited data on species‐specific tooth morphology match this conclusion. Significant differences in environmental conditions exist between sites where A. texanum with and without A. barbouri‐like mtDNA occur, suggesting a possible role for selection in the process of introgression. Overall, our study provides a general example of the value of using complimentary analyses to make inferences of the directionality, timescale, and source of mtDNA introgression in animals.
Impact of the functional status of saeRS on in vivo phenotypes of Staphylococcus aureus sarA mutants
Authors: Beenken Karen E. , Mrak Lara N. , Zielinska Agnieszka K. , Atwood Danielle N. , Loughran Allister J. , Griffin Linda M. , Matthews K. Alice , Anthony Allison M. , Spencer Horace J. , Skinner Robert A. , Post Ginell R. , Lee Chia Y. , Smeltzer Mark S.
Published: April 2014

We investigated the in vivo relevance of the impact of sarA and saeRS on protease production using derivatives of the USA300 strain LAC. The results confirmed that mutation of saeRS or sarA reduces virulence in a bacteremia model to a comparable degree. However, while eliminating protease production restored virulence in the sarA mutant, it had little impact in the saeRS mutant. Additionally, constitutive activation of saeRS (saeRSC) enhanced the virulence of LAC and largely restored virulence in the isogenic sarA mutant. Based on these results, together with our analysis of the representative virulence factors alpha toxin, protein A (Spa), and extracellular nucleases, we propose a model in which the attenuation of saeRS mutants is defined primarily by decreased production of such factors, while constitutive activation of saeRS increases virulence, and reverses the attenuation of sarA mutants, because it results in both increased production and decreased protease‐mediated degradation of these same factors. This regulatory balance was also apparent in a murine model of catheter‐associated infection, with the results suggesting that the impact of saeRS on nuclease production plays an important role during the early stages of these infections that is partially offset by increased protease production in sarA mutants.
Sensitivity to the two‐peptide bacteriocin lactococcin G is dependent on UppP, an enzyme involved in cell‐wall synthesis
Authors: Kjos Morten , Oppegård Camilla , Diep Dzung B. , Nes Ingolf F. , Veening Jan‐Willem , Nissen‐Meyer Jon , Kristensen Tom
Published: April 2014

Most bacterially produced antimicrobial peptides (bacteriocins) are thought to kill target cells by a receptor‐mediated mechanism. However, for most bacteriocins the receptor is unknown. For instance, no target receptor has been identified for the two‐peptide bacteriocins (class IIb), whose activity requires the combined action of two individual peptides. To identify the receptor for the class IIb bacteriocin lactococcin G, which targets strains of Lactococcus lactis, we generated 12 lactococcin G‐resistant mutants and performed whole‐genome sequencing to identify mutations causing the resistant phenotype. Remarkably, all had a mutation in or near the gene uppP (bacA), encoding an undecaprenyl pyrophosphate phosphatase; a membrane protein involved in peptidoglycan synthesis. Nine mutants had stop codons or frameshifts in the uppP gene, two had point mutations in putative regulatory regions and one caused an amino acid substitution in UppP. To verify the receptor function of UppP, it was shown that growth of non‐sensitive Streptococcus pneumoniae could be inhibited by lactococcin G when L. lactis uppP was expressed in this bacterium. Furthermore, we show that the related class IIb bacteriocin enterocin 1071 also uses UppP as receptor. The approach used here should be broadly applicable to identify receptors for other bacteriocins as well.
MicroRNA‐221 targeting PI3‐K/Akt signaling axis induces cell proliferation and BCNU resistance in human glioblastoma
Authors: Xie Qiang , Yan Yongrong , Huang Zuoping , Zhong Xueyun , Huang Lei
Published: April 2014

MicroRNAs (miRNAs) are short regulatory RNAs that negatively regulate protein biosynthesis at the post‐transcriptional level and participate in the pathogenesis of different types of human cancers, including glioblastoma. In particular, the levels of miRNA‐221 are overexpressed in many cancers and miRNA‐221 exerts its functions as an oncogene. Nevertheless, the roles of miRNA‐221 in carmustine (BCNU)‐resistant glioma cells have not been totally elucidated. In the present study, we explored the effects of miRNA‐221 on BCNU‐resistant glioma cells and the possible molecular mechanisms by which miRNA‐221 mediated the cell proliferation, survival, apoptosis and BCNU resistance were investigated. We found that miR‐221 was overexpressed in glioma cells, including BCNU‐resistant cells. Moreover, we found that miR‐221 regulated cell proliferation and BCNU resistance in glioma cells. Overexpression of miR‐221 led to cell survival and BCNU resistance and reduced cell apoptosis induced by BCNU, whereas knockdown of miR‐221 inhibited cell proliferation and prompted BCNU sensitivity and cell apoptosis. Further investigation revealed that miR‐221 down‐regulated PTEN and activated Akt, which resulted in cell survival and BCNU resistance. Overexpression of PTEN lacking 3′UTR or PI3‐K/Akt specific inhibitor wortmannin attenuated miR‐221‐mediated BCNU resistance and prompted cell apoptosis. We propose that miR‐221 regulated cell proliferation and BCNU resistance in glioma cells by targeting PI3‐K/PTEN/Akt signaling axis. Our findings may provide a new potential therapeutic target for treatment of glioblastoma.
TASK COMPLEXITY, ORGANIZATION SIZE, AND ADMINISTRATIVE INTENSITY: THE CASE OF UK UNIVERSITIES
Authors: ANDREWS RHYS , BOYNE GEORGE A.
Published: April 2014

The task complexity and size of public service organizations are arguably key determinants of the proportion of resources devoted to administration. Moreover, the combined effect of these two variables is also likely to have important implications for the scale of the administrative function. To explore the separate and combined effects of task complexity and size on administrative intensity in public service organizations, we examine the determinants of the relative proportion of resources allocated to central administration rather than academic departments in UK universities between 2003 and 2008. The results suggest that there is a non‐linear U‐shaped impact of both task complexity and size on administrative intensity, and that in combination these characteristics lead to a bigger central administrative component in universities. Theoretical and practical implications are discussed.
Frequency and distribution of the brown rust resistance gene Bru1 and implications for the Louisiana sugarcane breeding programme
Authors: Parco Arnold S. , Avellaneda Mavir C. , Hale Anna H. , Hoy Jeffrey W. , Kimbeng Collins A. , Pontif Michael J. , Gravois Kenneth A. , Baisakh Niranjan
Published: April 2014

Brown rust, caused by the fungus Puccinia melanocephala, poses an increasing threat to sugarcane industries worldwide. Recently, markers R12H16 and 9020‐F4 were developed for a major resistance gene Bru1 that contributes to a significant proportion of brown rust resistance in multiple sugarcane industries. Marker‐assisted screening of Louisiana sugarcane germplasm showed a low frequency (4.3%, five out of 117 clones) of Bru1 among sugarcane cultivars and elite breeding clones. Likewise, among progeny of crosses involving wild/exotic germplasm, only 14 of 208 clones (6.7%) tested Bru1 positive. However, Bru1 frequency was higher (28.7%, 52 of 181 clones) in wild/exotic germplasm, which indicated that diverse genetic resources are available for Bru1 introgression. Commercial Bru1‐positive cultivar, ‘L 01‐299', was resistant to brown rust. However, Bru1‐positive cultivar, ‘L 10‐146’, was susceptible while Bru1‐negative cultivars, such as ‘L 99‐233’, showed resistance to brown rust. Bru1‐negative clones with brown rust resistance offer an opportunity to identify alternate sources of resistance, which can be pyramided with Bru1 for effective and durable resistance in sugarcane against the changing pathogen.
Reply
Authors: Byrne Anthony , Bennett Michael , Chatterji Robindro , Symons Rebecca , Pace Nathan , Thomas Paul
Published: April 2014

See correspondence, page 769
A phylogenetic study of the generic relationships within the subtribe Leucophoropterina Schuh (Miridae: Phylinae: Leucophoropterini)
Authors: MENARD KATRINA L. , WOOLLEY JAMES B.
Published: April 2014

The subtribe Leucophoropterina (Miridae: Phylinae: Leucophoropterini) is a relatively small lineage of mirids comprising 23 genera and 104 species. Most of the species are endemic to the Indo‐Pacific and Australia, and many are considered ant mimics. A phylogenetic analysis including both the Australian and the Indo‐Pacific taxa was conducted for the first time with a dataset of 137 morphological characters coded for all but two known species of Leucophoropterina. The hypothesis by Schuh () of at least two major lineages of ant‐mimicking taxa based on his analysis of the Indo‐Pacific taxa continues to be supported with our inclusion of Australian taxa. The Australian taxa and Indo‐Pacific taxa of Leucophoropterina do not form independent, geographically based lineages, but instead comprise several lineages containing taxa from both regions. This study provides a basis for future detailed studies of biogeography and ant mimicry in the group.
‘Peopling’ geographies of peace: the role of the military in peacebuilding in the Philippines
Authors: Woon Chih Yuan
Published: April 2014

Geographical forays into peace research have flourished in recent years. Without denying the value of these works in highlighting the discipline's normative and practical contributions towards peace, this paper calls for further interrogations into the peoples who are involved in the (re)making of peaceful geographies. Using the case study of the military in the southern Philippines, I showcase the efforts of a particular group of soldiers in harnessing coalitional formations with local communities and NGOs for peaceful outcomes. Specifically, such collaborative partnerships enabled meaningful dialogues and negotiations to take place so as to pave the way for the attainment of truly sustainable peace. Hence, I contend that moving towards ‘peopled’ accounts of peace can proffer insights into the relationships and interactions between actors and how these facilitate transformative possibilities for peace. This will in turn create space for reflecting on the motivations and pathways in practising and realising peace. Such an actor‐centred approach to peace is particularly important at this political juncture when attempts are made to shift geography away from its traditional interest in warfare so as to grant new visibility to alternative peace cultures – it not only highlights the discipline's ethical responsibility towards peace and nonviolence but also facilitates academic action that is embodied and engaged.
Integrated management of Bromus diandrus in dryland cereal fields under no‐till
Authors: García A L , Royo‐Esnal A , Torra J , Cantero‐Martinez C , Recasens J
Published: April 2014

As herbicides have limited effect in controlling Bromus diandrus in no‐till dryland cereal fields, the integration of chemical and cultural methods needs to be investigated. A field study was carried out in Lleida (Spain) during 2008–09, 2009–10 and 2010–11 seasons, in a no‐till winter cereal field integrating delayed crop sowing with herbicides in a barley–wheat–wheat rotation. Three crop sowing dates were considered: D1, mid‐October; D2, mid‐November; and D3, early December, and the herbicides mesosulfuron‐methyl plus iodosulfuron‐methyl‐sodium were applied in wheat. Weed density, cumulative emergence and fecundity were estimated for each sowing date. In all three seasons, a significant reduction in the cumulative emergence of B. diandrus as compared to D1 was observed in D2 (82.0, 97.5 and 98.1%) and D3 (80.8, 98.7 and 97.2%). In addition, a significant decrease in weed density and seed rain was observed across all sowing dates and seasons. The herbicide used in wheat was more effective under delayed sowing, due to lower weed density and presence of less developed weed seedlings. After three seasons, the populations of B. diandrus were completely depleted in D2 and D3. This study demonstrates the possibility of eliminating brome infestations in dryland cereal fields in no‐till systems through the integration of cultural and chemical strategies.
Removal of Cadmium Using Ferro Magnetic Gels
Authors: Azizul Rahman Muhammad Aizat , Misran Effaliza , Idris Ani , Mohd Yusof Noordin
Published: April 2014

The removal of cadmium (Cd) from aqueous solution of cadmium chloride using ferromagnetic photocatalyst gel was investigated. The experiments were performed under sunlight and also away from sunlight. Recycling experiments were also performed to determine the durability of the ferromagnetic photocatalyst gel. The results revealed that removal of cadmium was higher in the presence of sunlight irradiation compared to without sunlight. Apparently the treatment process for Cd involved both adsorption and photocatalytic process. The removal rate of Cd was faster when it was exposed to sunlight where almost 100% of Cd was removed within 4 hours. The presence of pores was observed from FESEM images and such morphology was considered helpful for mass transfer of Cd(II) to the photocatalyst active sites embedded in the PVA-alginate magnetic beads. The PVA-alginate magnetic beads produced were reused after treating with 25 ppm of Cd(II) solutions without washing them. The performance of each cycle was about the same as the previous cycle until it reached the seventh cycle where the ferro photo gels start to lose its removal efficiency.
Extraction of Virgin Coconut (Cocos nucifera) Oil Using Supercritical Fluid Carbon Dioxide
Authors: Che Yunus Mohd Azizi , Rozak Muhammad Naim , Nian-Yian Lee , Ruslan Muhammad Syafiq Hazwan , Mohd-Setapar Siti Hamidah , Ahmad Zaini Muhammad Abbas
Published: April 2014

Bioactive compound is an important component in health care to a majority of the world’s population.  Virgin Coconut (Cocos nucifera) oil is used in Southeast Asia for treating various diseases and is well-known of its rich nutrients.  In this study, supercritical fluid extraction (SFE), an environmental friendly technique was used to extract the interest compounds from crude virgin coconut. The extracted virgin coconut oil is free from organic solvent and safe to be consumed. This is because the solvent used in the extraction process is carbon dioxide which is inert and no solvent residue inside the extracted oil. The layout of the experiment was developed via Statistica 8.0 using the Box-Behnken experimental design model. The oil yield, antioxidant activity and total phenolic content were calculated while the comparison of the experimental results and the statistical data was done using response surface methodology (RSM). Therefore, the optimum conditions of temperature and pressure for the extraction of virgin coconut oil was obtained through the statistical study which is 47°C and 20MPa respectively.
Prediction of Kraft Lignin Extraction Performance Using Emulsion Liquid Membrane Carrier-Diffusion Model
Authors: Nyuk Yan Chan , Othman Norasikin , Zing Yi Ooi
Published: April 2014

This study presents the model to predict the performance of emulsion liquid membrane (ELM) to extract kraft lignin. Kraft lignin is one of the raw material that can be convert into biodiesel and also applied in producing large amount of chemical product such as vanillin. ELM is a separation method which can separate component without mechanical support. In this study, ELM model was developed and solved using MATLAB software. Three parameters were investigated in this study such as treat ratio, carrier concentration and initial concentration of feed phase. The study shows that ELM performs best at treat ratio of 1:5, concentration carrier of 0.3M and 0.5g/L of initial concentration of feed phase.
Composite Chitosan Membranes for the Separation of Methanol/methyl tert-butyl Ether Mixtures
Authors: Mohd Nawawi Mohd Ghazali , Zamrud Zafifah
Published: April 2014

Composite membranes from chitosan blended with different ratios of chitosan were developed for the pervaporation of methanol/methyl tert-butyl ether mixtures. The composite membranes were characterized for surface morphology and sorption. Surface morphology showed chitosan and PVA were homogenously blend for all chitosan composition. Swelling characteristics of composites membrane were affected by methanol concentration as well as chitosan composition in the blend. Increasing feed temperatures and methanol concentration in the feed in pervaporation increased the flux and decreased the separation factor. The composite membranes containing 20 to 40 wt% chitosan was chosen as the preferred membrane formulation to yield fluxes ranging from 50 to 70 g/m2hr with separation factors ranging from 55 to 80 at optimum operating conditions of 30 wt% methanol in the feed and feed temperature of 50 0C.
Progressive Freeze Concentration of Coconut Water
Authors: Jusoh Mazura , Mohamed Nor Noor Naimah , Zakaria Zaki Yamani
Published: April 2014

In order to provide convenience for consumers around the world, it is highly beneficial if the nutritious coconut water (CW) could be concentrated and just easily be added with water for later consumption. A new concentration technique is required to eliminate some parts of the water from the CW while retaining its nutritious and unique aroma. As Progressive Freeze Concentration (PFC) could retain the nutritional compounds, it was applied to concentrate CW and reduce its volume. In PFC system, only a single block of ice is formed as a layer on the cooled surface. A coil stainless steel crystallizer was used as FC unit to investigate the enhancement of sugar content in CW. The effect of initial concentration of CW was then investigated on the performance of the PFC system through the Effective Partition Constant (K) value and increment of sugar content. It was found that low initial concentration and intermediate coolant temperature yielded lower K value and high increment of sugar content. The best K achieved was 0.3101 and the highest increment of sugar content was 53% at initial concentration of 3 %Brix and coolant temperature of 12°C.
Large Signal Model of Heterojunction Bipolar Transistor InP/InGaAs as an Optoelectronic Mixer
Authors: Shaharuddin N. A. , Idrus S. M. , Isaak S. , Mohamed N. A. , Yusni N. A. A.
Published: April 2014

A large-signal model of InP/InGaAs single Heterojunction Bipolar Transistor (HBT) has been developed considering spectral performance and mixing. This model is based on Gummel Poon BJT model. HBT InP/InGaAs has been modeled and analyzed in this paper as an optoelectronic mixer (OEM). The HBT proposed was simulated by considering the wavelength of 1310 nm for an up-conversion frequency of 30 GHz. Its characteristics was further investigated to develop the appropriate structure device for OEM application. This proposed HBT InP/InGaAs can be potentially implemented in the broadband Radio over Fiber (RoF) system to perform photodetection and frequency up-conversion.
Feature Analysis of Numerical Calculated Data from Sweep Frequency Analysis (SFRA) Traces Using Self Organizing Maps
Authors: Bohari Z. H. , Ab Ghani S. , Baharom M. F. , Nasir M. N. M. , Jali M. H. , Md Thayoob Y. H.
Published: April 2014

This paper presents a comprehensive investigation of the Self Organizing Map (SOM) classification process of good and defective power distribution transformers. Three main features were extracted from the numerical calculation method of the Sweep Frequency Response Analysis (SFRA) signals acquired from the transformers. These features are the input vectors for the SOM classification. Analysis of the results has shown the capability of the features and the SOM classification method to differentiate between good and defective transformers.
Using Pyroelectric Sensors to Detect Continuous Infrared Radiation
Authors: Heydarianasl Mozhde , Rahmat Mohd Fua’ad
Published: April 2014

This paper focuses on an optimized method for detecting continuous infrared rays make use of Pyroelectric devices. Now, Pyroelectric devices are usually very sensitive to changes in infrared radiation in the presence of an object when transfers or radiation is connected or disconnected. In this new approach, the thermo-electric cooler is employed to active temperature sensors instead of conventional modulation. They use mechanical parts, which are complex and un-reliable. The most of the sensor consists of a number of important restrictions, which are expected to be eliminated by a new method in this study. To simulate the thermal and electrical behavior of the detector, the equivalent electrical circuit is needed that will be proposed.The practical results of Pyroelectric sensor are sent to a computer by a digital oscilloscope, and then they are monitored and analyzed. After that, the model is simulated with MATLAB software. Finally, practical and theoretical results compared with each other and a good agreement of them is shown and confirms the validity of the model.
Design of Dual Band Antenna for WLAN Application
Authors: Shukor M. Md. , Abd. Aziz M. Z. A. , Ahmad B. H. , Suaidi M. K. , Othman M. A.
Published: April 2014

This paper presents the antenna designed with radiating structure of 3.5 for dual band applications. This antenna is designed and simulated by using CST Studio Suite software at 2.4 GHz and 5.2 GHz based on standard IEEE 802.11a (5.15 GHz-5.35 GHz) and IEEE 802.11b (2.4 GHz-2.48 GHz) frequency bands. The radiating structure 5 and 3 are designed to radiated at frequency 2.4 GHz and 5.2 GHz respectively. Then, both structures are combined to achieve dual band resonant frequencies. The techniques that have been used to achieve dual band resonant are by designing the 3.5 shaped by using planar and coplanar waveguide (CPW) structures. There are three designs of dual band antenna which are Design A, Design B and Design C. The optimum return loss for 2.4 GHz and 5.2 GHz frequency response are -16.44 dB and -18.78 dB respectively achieved by Design C. The changes on the position of radiating structure 3 will effects the frequency response, return loss and gain of the antenna.
Lightweight Mortar Incorporating Various Percentages of Waste Materials
Authors: Mehmannavaz Taha , Ismail Mohammad , Radin Sumadi Salihuddin , Samadi Mostafa , Sajjadi Seyed Mahdi
Published: April 2014

The experimental study evaluated the performance of lightweight aerated concrete incorporating various percentages of palm oil fuel ash (POFA) and pulverized fuel ash (PFA) as partial cement replacement. Performance evaluation of the aerated concrete was investigated with respect to ultimate compressive strength, density and strength development. Twelve mixes are developed and tested at different periods, i.e. 3, 7and 28 days. In this work, two different curing regime namely air curing and water curing were used to monitor the effect of the curing regime. The results show that the mixtures produced by replacing cement with POFA and PFA were comparable to the mix without cement replacement. Furthermore, this investigation observed that the cement-POFA-PFA based lightweight aerated concrete can be produced as lightweight non-load bearing concrete units, because hazard of ashes (POFA & PFA) might be a serious issue for human health. Disposal of ashes contributes the shortage of landfill space in all the worlds, especially in Malaysia.
Thermodynamic Analysis of Glycerol Steam Reforming to Ethylene
Authors: Zakaria Zaki Yamani , Linekoski Juha , Saidina Amin Nor Aishah
Published: April 2014

Thermodynamic equilibrium analysis of glycerol steam reforming to ethylene has been investigated based on the total Gibbs free energy minimization method. Equilibrium product compositions for glycerol steam reforming were determined for temperatures ranging from 573–1273 K and GWR (glycerol/water ratio) 1:12 to 2:1 at 1 bar pressure. The objectives of this study are to identify the thermodynamic range of the process operation and study the variation of product distribution. It was found that the formation of ethylene was difficult to accomplish and the amount of ethylene produced is very small. The formation of coke, which will poison the catalyst, could be suppressed at higher operating temperature. The thermoneutral temperature of the process was found to increase with GWR. Other means to encourage the formation of more ethylene is required.
Dynamic Energy Absorption Performances of Rain Forest Vehicle (RFV) under Frontal Impact
Authors: Othman M. S. , Ahmad Z.
Published: April 2014

This paper treats the crash analysis and energy absorption response of Rain Forest Vehicle (RFV) subjected to frontal impact scenario namely impacting rigid wall and column. Dynamic computer simulation techniques validated by experimental testing are used to carry out a crash analysis of such vehicle. The study aims at quantifying the energy absorption capability of frontal section of RFV under impact loading, for variations in the load transfer paths and geometry of the crashworthy components. It is evident that the proposed design of the RFV frontal section are desirable as primary impact energy mitigation due to its ability to withstand and absorb impact loads effectively. Furthermore, it is found that the impact energy transmitted to the survival room may feasibly be minimized in these two impact events. The primary outcome of this study is design recommendation for enhancing the level of safety of the off-road vehicle where impact loading is expected.
Separation of CO2 by Using Aqueous Mixtures of AMP and [B3MPYR][BF4] at High Pressure
Authors: Nordin Syamila , Mohd Salleh Ruzitah , Ismail Norhuda
Published: April 2014

In this study, CO2 absorption capacity in aqueous mixtures of 2-amino-2-methyl-1-propanol, (AMP) and N-butyl-3-methylpyridinium tetrafluoroborate, [B3MPYR][BF4] was measured at pressures from 200 kPa up to 5000 kPa and temperatures of 303.15 K - 333.15 K. The AMP concentration was maintained at 1 M while the [B3MPYR][BF4] concentration ranges from 0.05 M to 0.3 M. It was observed that CO2 loading capacity increases when the pressure increased. However, increasing of temperature will decrease the CO2 loading. From the experimental results, a simple correlation, as suggested by Jou and Mather was used to predict the CO2 loading in the aqueous AMP-[B3MPYR][BF4] mixtures. The model were found to be in a good agreement with the experimental results where only 1.66% of the predicted values deviate more than 20% compared to the experimental values.
Effect of Temperature and Air flow rate on Xylene Removal from Wastewater using Packed Column Air Stripper
Authors: Kamarden Hamidah , Abu Hassan Mohd. Ariffin , Noor Zainura Zainon , Ibrahim RK Raja , Evuti Abdullahi Mohammed
Published: April 2014

In this research, the effects of temperature and air flow rate on the removal efficiency of xylene from wastewater using packed column air stripper were investigated at a temperature range of 30 to 500C and air-water ratios of 20 to 100. The quantities of xylene in effluent from the air stripper were determined using UV-visible spectrophotometer. The effects of increase in temperature on the percentage removal of xylene were found to be more significant at low temperatures (30-400C) than at higher temperatures (45-500C). Also, the effects of increase in water-air ratio on percentage removal of xylene were less significant at higher G/L ratio (80-100) and more significant at low G/L ratios (20-60), thus revealing a non-linear trend in the effect of temperature and air-water ratio on xylene removal.The result also indicates that xylene removal efficiency is greatly affected by column temperature and G/L ratio with the highest removal efficiency of 99.93 at temperature of 500C and at G/L ratio of 100.
Liquid-liquid Phase Separation in Batch Settling with Inclined Plate
Authors: Mungma Nuttakul , Chuttrakul Pornprapa , Pfennig Andreas
Published: April 2014

Liquid-liquid dispersions which are occurring in the petrochemical and chemical industry are commonly separated in gravity settlers. To improve the settler design, phase separation of the dispersions was studied. The parameters having the greatest effect on the phase separation under gravity are drop size, drop-size distribution, as well as driving-force parameters for sedimentation and coalescence, namely density difference, viscosity and interfacial tension. The effect of the driving-force parameters on coalescence and sedimentation was characterized experimentally using a standardized batch-settling cell. The viscosity of the aqueous phase was increased by adding polyethylene glycol. This not only changed the viscosity but also the interfacial tension, having a significant impact on drop size. In high-viscosity systems the settling speed of swarm droplets will significantly slow down and droplet size will be smaller. Furthermore, internals in gravity settlers also have significant impact on the phase separation. The influence of internals was studied for inclined plates. It can be seen from the experiments that internals speed up coalescence for different viscosities and volume ratios between the phases up to a factor of two.
Effect of Extraction Time on Degradation of Bioactive Compounds (Zingiber Officinale Roscoe)
Authors: Aris Nor Ilia Anisa , Morad Noor Azian Morad
Published: April 2014

Ginger, the rhizome of Zingiber officinale contains the bioactive compounds that have a long history of medicinal usage. The two most abundant ginger bioactives identified are 6-gingerol and 6-shogaol. It is important that the availability of these bioactives are first identified. This is done through ethanol extraction. Thus, this paper identified the effect of extraction time using ethanol on the overall yield and concentration of 6-gingerol and 6-shogaol. Kinetic studies on degradation of the bioactive compounds also have been studied. Fourier transform infrared (FTIR) spectroscopy was applied as an additional tool for the characterization of the compounds and in identifying the degradation circumstances. Results showed that the highest overall yield was obtained after 8 hours of extraction. In consistent with the overall yield of extraction, the concentration of 6-gingerol and 6-shogaol reached equilibrium within 8 hours. The concentration of 6-gingerol and 6-shogaol are 13923.26 and 4816.84 μg/g, respectively. Conclusively, the saturated concentration of zingiber bioactive compounds could be determined through ethanol extraction within 8 hours.
Ultrasound-Assisted Extraction of Lignin from Oil Palm Frond
Authors: Ngadi Norzita , Rusli Nur Shahirah Rusli
Published: April 2014

Ultrasound-assisted method is claimed as a simpler and more effective ways of extracting compared to conventional extraction methods for the extraction of bioactive compounds from natural products such as lignin. This study investigated the potential of ultrasound-assisted extraction to extract lignin from oil palm frond (OPF) as compared to conventional heating. The extraction had been carried out by using sodium hydroxide solution as a solvent. Factors such as extraction temperature and solvent concentration were also examined. The presences of lignin in the corresponding extracts were confirmed by FTIR analysis. The result obtained showed that the extraction of OPF assisted with ultrasound was more efficient in giving higher lignin yield compared to conventional heating. Other than that, the reaction temperature was lowered down and the reaction time was also shortened when the extraction was assisted by ultrasound. With all these merits, ultrasound-assisted extractions were more effective to be used and should be considered for a wider application in the extraction of lignin and other compounds from various plants.