bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermal resistance of GaAs/AlAs superlattices used in modern light-emitting diodes
Authors: Żak D. , Nakwaski W.
Published: March 2014

Superlattices are used in modern light-emitting diodes to modify intentionally electron, phonon and/or photon transport within their volumes, which leads to their expected performance characteristics. In particular, superlattices may have a dramatic impact on device thermal properties. Superlattice thermal resistance is anisotropic and usually distinctly higher than its values in constituent bulk materials, which results from phonon reflections and/or phonon scatterings at numerous layer interfaces. In the present paper, thermal resistance of a typical superlattice of layer thicknesses neither much higher nor much lower than the phonon free path is discussed. Besides, as an important example, thermal resistance of the typical GaAs/AlAs superlattice is determined theoretically and compared with its measured values known from literature.
Intracavity polarization control in mode-locked Er-doped fibre lasers using liquid crystals
Authors: Nikodem M. , Krzempek K. , Zygadlo K. , Dudzik G. , Waz A. , Abramski K. , Komorowska K.
Published: March 2014

In this paper we present a novel configuration of an NPR mode-locked Er-doped laser. This new optical setup uses voltage controlled LC cells to replace standard retarders (quarter-and half-waveplates) inside the laser cavity. Using this novel, mechanical-adjustment-free setup a mode-locking was obtained with sub-500 fs pulse duration and an average power exceeding 40 mW. Presented results show that using simple LC cells, an optical layout of an NPR mode-locked laser can be greatly simplified.
Compositional arrangement of rod/shell nanoparticles: an approach to provide efficient plasmon waveguides
Authors: Ahmadivand A. , Golmohammadi S.
Published: March 2014

In this work, we investigated the optical properties of a novel compositional configuration of gold nanorod and silver nanoshell which is embedded in a SiO2 substance. The proper geometrical sizes for compositional rod/shell arrangement have been obtained based on the position and peak of plasmon resonance at λ ∼1550 nm. Adjusting the plasmon resonance position at declared spectrum helps us to provide an arrangement which shows high efficiency and minimum losses. The influence of destructive components such as internal damping and scattering on the rod/shell combination is demonstrated by corresponding diagrams. Moreover, we proposed a nano-array based on examined configuration and the quality of light transmission along the array is studied. We figured out and depicted optical properties of the array such as transmission loss factors, group velocities, transmitted power, transmission quality, and two-dimensional snapshots of surface plasmons (SPs) coupling between nanoparticles arrangements under transverse and longitudinal modes excitations. Ultimately, it is shown that the suggested nanostructure based on studied nanoparticles configuration has a potential to utilize in designing nanophotonic devices such as splitters, couplers, and routers. Finite-difference time-domain method (FDTD) as a major simulation model has been employed to study the features of the waveguide.
Study of the effect of director fluctuations on liquid-crystalline molecular reorientation
Authors: Sierakowski M. , Woliński T. , Orzechowski K.
Published: March 2014

Initial phase of field-induced molecular reorientation in threshold geometry of a liquid-crystalline structure is essentially influenced by thermal orientational fluctuations. Still not quite clear is the way in which the reorientation starts and how it runs over an LC-structure in its initial phase. Fluctuations are stochastic events in time and also in space. This feature suggests, that the reorientation process may be induced by director fluctuations locally in a particular part of the LC-structure. In this work we have studied the impact of fluctuations on the molecular reorientation in nematics involving optical nonlinear interaction. The restricted area of a nematic layer was excited by light beam that amplified director fluctuations locally. By manipulation of optical excitation we were able to affect the dynamics of the effect. Since the threshold-type configuration of nematics is used in a number of optical devices, the obtained results may have practical aspect contributing to a new way of controlling the field-induced transition.
POPULATION AND COMPARATIVE BEHAVIOUR OF OCHOTONA ROYLEI AND OCHOTONA MACROTIS IN GOSAINKUNDA AREA, LANGTANG NATIONAL PARK, NEPAL
Authors: Koju Narayan P. , Chalise Mukesh K. , Kyes Randall C
Published: March 2014

Study on the behavior of pika (Ochotona roylei and O. macrotis) was carried out during the monthsof July and August 2011 in Gosainkunda, Langtang National Park (LNP), Nepal. Pika inhabits in thetalus habitats of the alpine area. Tharepati (3651 m asl), Phedi (3825 m asl), Gosainkunda (4436 masl), and Laurebina (3903 m asl) were selected for behavior recording. Quadrates of 50 m × 50 mwere randomly plotted at each site except in Phedi. Only two species of pika were recorded in thoseareas: Ochotona macrotis was 75 individuals and Ochotona roylei 49 individuals. The ratio of agegroup adult and infant in O. macrotis was 29:46 and O. roylei 16:33 population with density 21/haand14/ha, respectively. Eleven pikas were observed for 455 min to record their behaviour from 5:30AM to 19:30 PM in each day. Feeding, foraging, musing, grooming, chasing each other (playing)were the recorded behavior. They were active at dawn and dusk but were not observed during rainyperiod. They spent their 26% of time in feeding, 24% in musing, 16% in foraging, and 11% ingrooming. Pikas were observed digging soft rocks, soil and mosses on the rock before dischargingpellets.Study on the behavior of pika (Ochotona roylei and O. macrotis) was carried out during the months of July and August 2011 in Gosainkunda, Langtang National Park (LNP), Nepal. Pika inhabits in the talus habitats of the alpine area. Tharepati (3651 m asl), Phedi (3825 m asl), Gosainkunda (4436 m asl), and Laurebina (3903 m asl) were selected for behavior recording. Quadrates of 50 m × 50 m were randomly plotted at each site except in Phedi. Only two species of pika were recorded in those areas: Ochotona macrotis was 75 individuals and Ochotona roylei 49 individuals. The ratio of age group adult and infant in O. macrotis was 29:46 and O. roylei 16:33 population with density 21/ha and14/ha, respectively. Eleven pikas were observed for 455 min to record their behaviour from 5:30 AM to 19:30 PM in each day. Feeding, foraging, musing, grooming, chasing each other (playing) were the recorded behavior. They were active at dawn and dusk but were not observed during rainy period. They spent their 26% of time in feeding, 24% in musing, 16% in foraging, and 11% in grooming. Pikas were observed digging soft rocks, soil and mosses on the rock before discharging pellets. DOI: http://dx.doi.org/10.3126/eco.v19i0.9853EcoprintAn International Journal of EcologyVol. 19, 2012Page: 57-62Uploaded date: 2/14/2014
ROLE OF WOOD WATER PROPERTIES AND LEAF DYNAMICS IN PHENOLOGY AND RESPONSE TO DROUGHT IN EVERGREEN HIMALAYAN TREE SPECIES
Authors: Poudyal Kanta , Jha P. K. , Zobel D. B.
Published: March 2014

Five evergreen Himalayan trees namely Castanopsis indica, Schima wallichii, Rhododendron arboreum, Quercus lanata and Q. semecarpifolia were studied for their phenological responses to drought. Wood water properties (wood moisture percentage, wood density and water in wood per volume), starch percentage content, specific leaf mass, nitrogen content in leaves and phenological processes such as leaf emergence, senescence, flowering and fruiting were measured. Measurements were taken 28 times from December 1998 to April 2001 except for the monsoon months. There was significant variation in starch percentage in zero and one year old twigs. Mean starch percentage content ranged from 23% and 17.1% (S. wallichii) to 64% and 61.7% (C. indica) in zero year and one year old twig, respectively. Wood water properties were highest in R. arboreum and lowest in C. indica. SLM showed significant variation with sampled species and mean SLM was highest in R arboreum (1.6 × 10-2 g cm-2) and lowest in S. wallichii (0.64 × 10-2 g cm-2). Mean N ranged from 1.13% (R arboreum) to 1.98% (C. indica). Reserved starch percentage and SLM had a strong effect on phenological activities. They increased during the vegetative bud break and leaf emergence and decreased during senescence. Similarly, leaf nitrogen in the studied species was at the crest of concentration during leaf initiation then declined, one in expanded leaves as the concentration became diluted by increasing cell wall material, and the other at the time of senescence by resorption. DOI: http://dx.doi.org/10.3126/eco.v19i0.9857Ecoprint An International Journal of Ecology Vol. 19, 2012 Page: 71-84 Uploaded date: 2/14/2014
Drug resistance tuberculosis: a global menace
Authors: Marahatta SB
Published: March 2014

DOI: http://dx.doi.org/10.3126/jmmihs.v1i2.9901 Journal of Manmohan Memorial Institute of Health Sciences Vol.1(2) 2013; 1-2
Risk factors of stigma related to leprosy - A Systematic Review
Authors: Adhikari Bipin , Kaehler Nils , Raut Shristhi , Marahatta Sujan Babu , Ggyanwali Kapil
Published: March 2014

DOI: http://dx.doi.org/10.3126/jmmihs.v1i2.9902 Journal of Manmohan Memorial Institute of Health Sciences Vol.1(2) 2013; 3-11
[Temporarily Withdrawn] Oxidative stress in the pathogenesis of systemic lupus erythematosus
Authors: Shah Dilip , Khanal Puspa Raj , Sah Sangita , Paudyal Bishnuhari
Published: March 2014

This paper was temporarily withdrawn on 28th May 2014 due to a number of errors in the final version of the paper.DOI: http://dx.doi.org/10.3126/jmmihs.v1i2.9905 Journal of Manmohan Memorial Institute of Health Sciences Vol.1(2) 2013; 26-37
Nepal needs midwifery
Authors: Bogren M , Bajracharya U. , Berg M , Erlandsson K , Ireland J , Simkhada P , Van Teijlingen Edwin
Published: March 2014

DOI: http://dx.doi.org/10.3126/jmmihs.v1i2.9907 Journal of Manmohan Memorial Institute of Health Sciences Vol.1(2) 2013; 41-44
Transurethral Holmium laser cystlithotripsy using 80 watt energy
Authors: Sharma Suman
Published: March 2014

DOI: http://dx.doi.org/10.3126/jmmihs.v1i2.9908 Journal of Manmohan Memorial Institute of Health Sciences Vol.1(2) 2013; 45-46
Development of biomimetic gelatin–chitosan/hydroxyapatite nanocomposite via double diffusion method for biomedical applications
Authors: Raz Majid , Moztarzadeh Fathollah , Shokrgozar Mohammad A. , Azami Mahmoud , Tahriri Mohammadreza
Published: March 2014

In this research, nanocomposite scaffolds were prepared from gelatin/chitosan and hydroxyapatite via a biomimetic method. The prepared scaffolds were then evaluated by means of commonly used bulk techniques: X-ray diffraction, scanning electron microscopy and Fourier transform infra-red spectroscopy. In this study, the gelatin–chitosan/apatite nanocomposite scaffolds were fabricated using the applied biomimetic method accompanied by freeze drying. The apatite was formed using double diffusion within the gelatin/chitosan hydrogel at similar pH and temperature to the human body. The obtained nanocomposites were soaked in glutaraldehyde solution in order to enhance their mechanical properties and also make them insoluble in water. Diffusion of calcium and phosphate ions from lateral sides into the hydrogel middle caused formation of a white layered precipitate. Analysis of precipitates formed within the hydrogel middle for the samples showed that detected materials are composed of carbonated hydroxyapatite and amorphous dicalcium phosphate dihydrate. After incubation in simulated body fluid, the amorphous phase converted to crystalline hydroxyapatite, which process is similar to bone formation in the human body. Mechanical properties obtained for the scaffolds were comparable to spongy bone. Also in this work, MTT assay and alkaline phosphatase activity on the prepared scaffolds were evaluated and discussed. Finally, the obtained experimental results ascertained that the nanocomposite prepared with chitosan/gelatin (20/80) had appropriate properties for bone tissue engineering scaffold.
Classical controlled rolling of low C steels microalloyed with Ti and Mo
Authors: Calvo Jessica , Collins Laurie , Yue Stephen
Published: March 2014

Two low-C steels, one microalloyed with Ti and the other with Ti and Mo were subjected to a classical controlled rolling schedule using torsion testing. The specific torsion schedules were a simulation of an industrial schedule adapted to the characteristic transformation temperatures of each steel. It is shown that such steels can develop a pancaked austenite, despite the fact that the alloys do not contain Nb. However, compared to Nb bearing steels, restoration between deformation passes is relatively rapid in the pancaking region. In order to reduce the loss of pancaking, the temperatures of the finishing rolling schedule were shifted to lower temperatures. This appeared to greatly reduce the restoration rates, but the transformation in the two phase region occurred towards the end of the final deformation pass. When comparing the two steels, it could be detected that Mo increases the temperature range for pancaking and reduces the restoration rates between deformation passes in the pancaking region.
Spatio-temporal analysis of surface elevation changes in Pine Island Glacier, Antarctica, from ICESat GLAS data and ERS-1 radar altimeter data
Authors: Herzfeld Ute C. , Wallin Bruce
Published: March 2014

Characterized by fast movement, low surface slope and grounding below sea level, Pine Island Glacier (PIG) plays an important role in the stability of the West Antarctic ice sheet. In previous work, we reported that the spatial distribution of 1995–2003 surface lowering in PIG suggests an attribution of changes to an internally forced process in the glacier. Other work associates changes in PIG entirely with processes in its ice shelf. Here time series of maps of surface elevation change in PIG and its ice shelf are derived from geostatistical analysis of ICESat GLAS and ERS-1 radar altimeter data. Based on spatio-temporal analysis of 1995–2007 elevation change, we discuss indications of processes that initiate from changes in the ice shelf versus processes that start internally in the glacier. Thinning rates continued to increase after 2003, regionally to >15 m a–1. The initiation of acceleration occurred in the interior of the ice stream, while in later years largest elevation loss was driven by changes in the ice shelf and upward propagation. By 2006, the region of thinning had expanded up-glacier beyond the initial areas of surface lowering to 100 km above the hinge line. More than one process causes dynamically complex changes in PIG.
Variations in water level and glacier mass balance in Nam Co lake, Nyainqentanglha range, Tibetan Plateau, based on ICESat data for 2003-09
Authors: Wu Hongbo , Wang Ninglian , Jiang Xi , Guo Zhongming
Published: March 2014

Water level fluctuations of inland lakes are related to regional-scale climate changes, and reflect variations in evaporation, precipitation and glacier meltwater flowing into the lake area in its catchment. In this paper, Ice, Cloud and land Elevation Satellite (ICESat) altimeter data and Landsat imagery (2002-09) are used to estimate Nam Co lake (Nyainqentanglha range, Tibetan Plateau) water elevation changes during 2002-09. In 2003 Nam Co lake covered an area of ~1998.8 ± 4.2 km2 and was situated at 4723 m a.s.l. Over such inland water bodies, ICESat altimeter data offer both wide coverage and spatial and temporal accuracy. We combine remote-sensing and GIS technology to map and reconstruct lake area and increased volume changes during a 7 year time series. Nam Co lake water level increased by 2.4±0.12m (0.33ma–1) between 23 February 2003 and 1 October 2009, and lake volume increased by 4.9 ±0.5 km3. In the past 7 years, Nam Co lake area has increased from 1998.78 ±5.4 to 2023.8 ±3.4 km2, the glacier-covered area has decreased from 832.34 to 821.0 km2 and the drainage basin area has decreased from 201.1 ±4.2 to 196.1 ±2.3 km2. However, the most spectacular feature is the continual water level rise from 2003 to 2009 without an obvious associated increase in precipitation. Based on digital elevation models (DEMs) from Shuttle Radar Topography Mission (SRTM) DEM data and corrected ICESat elevation data, significant changes to glacier mass balance in the western Nyainqentanglha mountains are indicated. Nyainqentanglha mountain glacier surface elevations decreased by 8.39 ± 0.45 m during 2003-09. Over the same period, at least 1.01 km3 of glacial meltwater flowed into Nam Co lake, assuming a glacial runoff coefficient of 0.6. The mean glacier mass-balance value is -490mmw.e. over the corresponding period, indicating that glacier meltwater in the catchment contributes to lake level rise. The contribution rate of glacial meltwater to lake water volume rise is 20.75%. The temporal lake level fluctuation correlates with temperature variations over the same time span.
21st-century increase in glacier mass loss in the Wrangell Mountains, Alaska, USA, from airborne laser altimetry and satellite stereo imagery
Authors: Das Indrani , Hock Regine , Berthier Etienne , Lingle Craig S.
Published: March 2014

Alaskan glaciers are among the largest regional contributors to sea-level rise in the latter half of the 20th century. Earlier studies have documented extensive and accelerated ice wastage in most regions of Alaska. Here we study five decades of mass loss on high-elevation, land-terminating glaciers of the Wrangell Mountains (~ 4900 km2) in central Alaska based on airborne center-line laser altimetry data from 2000 and 2007, a digital elevation model (DEM) from ASTER and SPOT5, and US Geological Survey topographic maps from 1957. The regional mass-balance estimates derived from center-line laser altimetry profiles using two regional extrapolation techniques agree well with that from DEM differencing. Repeat altimetry measurements reveal accelerated mass loss over the Wrangell Mountains, with the regional mass-balance rate evolving from –0.07 ± 0.19 m w.e. a–1 during 1957–2000 to –0.24 ± 0.16 m w.e. a–1 during 2000–07. Nabesna, the largest glacier in this region (˜1056 km2), lost mass four times faster during 2000–07 than during 1957–2000. Although accelerated, the mass change over this region is slower than in other glacierized regions of Alaska, particularly those with tidewater glaciers. Together, our laser altimetry and satellite DEM analyses demonstrate increased wastage of these glaciers during the last 50 years.
Correlation and path coefficient studies of yield and yield attributing characters in panikachu, Colocasia esculenta (L.) Schott
Authors: Paul KK , Bari MA , Debnath SC
Published: March 2014

The study was made to identify the association of yield and stolon characters and their direct and indirect effects in panikachu, Colocasia esculenta (L.) Schott. The stolon number, single stolon weight, total stolon weight, stolon length, length and breadth of corm and weight of corm showed positive correlation with yield per plant of which single stolon weight and corm breadth showed significant positive correlation with yield per plant at phenotypic level. Stolon breadth exhibited significant positive correlation with yield per plant at genotypic level. The residual effect in the genotypic level was 0.2205 which indicated this character contributed 78% of the yield. Results obtained suggested that maximum emphasis should be given on characters in selecting panikachu genotypes with higher yield per plant and the residual effect in phenotypic level was 0.4235 indicating 58% variability contributed by these characters. DOI: http://dx.doi.org/10.3329/jbas.v37i2.17552 Journal of Bangladesh Academy of Sciences, Vol. 37, No. 2, 131-137, 2013
Growth, structural, thermal and optical properties of Mg2+ -Co2+ doped potassium acid phthalate crystals
Authors: Hossain Mostak , Begum Shahan Ara , Podder Jiban
Published: March 2014

Single crystals of pure potassium acid phthalate (KAP) and magnesium-cobalt (Mg2+-Co2+) co-doped potassium acid phthalate crystals were grown by an isothermal evaporation method. Optically transparent and coloured KAP single crystals were grown by doping divalent bimetallic impurities. Enhancement of the metastable zonewidth was achieved by the addition of co-doped bimetallic impurities in KAP solution. It is anticipated that these larger cations play a vital role in the growth mechanism and it favours to reduce the formation of secondary nucleation by positioning the doped metal ions into the interstitial sites. The XRD results confirm that the incorporation of bimetallic ions into the KAP crystal lattice. The optical transmission is found to decrease in Mg-Co doped crystals compared to that of pure KAP. DOI: http://dx.doi.org/10.3329/jbas.v37i2.17557 Journal of Bangladesh Academy of Sciences, Vol. 37, No. 2, 165-172, 2013
Correlation between cane growth and flowering behavior of Dendrobium orchid cultivars
Authors: Islam MS , Mehraj H , Roni MZK , Shimasaki K , Uddin AFM Jamal
Published: March 2014

The experiment was conducted to observe the correlation of cane growth with floral behavior of nine Dendrobium cultivars. Results revealed that, cane growth of different Dendrobium cultivars influenced flowering behavior. The present experimental findings may help to determine standard cane growth for efficient nutrient management and commercial grade flower production of Dendrobium cultivars. DOI: http://dx.doi.org/10.3329/jbas.v37i2.17561 Journal of Bangladesh Academy of Sciences, Vol. 37, No. 2, 205-209, 2013
Enhanced photocontrolled binding of Ag+ by thioindigo derivative containing oxyethylene chains with OH groups at the terminal positions
Authors: Rahman Shah Mohammad Fatah-Ur , Shahjin Farah , Fukunishi Koushi
Published: March 2014

A novel thioindigo dye was synthesized, from 7, 7-bis-chlorocarbonyl thioindigo, containing OH groups at the terminal positions of the oxyethylene side chains. The resultant dye 7, 7-Bis[[2- [2-(2-hydroxyethoxy)ethoxy]ethoxycarbonyl]thioindigo (1) was characterized by 1H NMR, IR, and mass spectral studies. The thioindigo derivative (1), which possesses a molecular architecture, undergoes reversible photochromic reaction and capable of capturing different metal ions and transports them through liquid membrane. Enhancement of binding ability (i) by incorporating OH groups instead of large phenyl or methyl groups, (ii) by trans to cis photoisomerization of (1), iii) the highest amount of transported Ag+ by (1) across a liquid membrane when irradiated with 550 and 480 nm light alternately, were found. DOI: http://dx.doi.org/10.3329/jbas.v37i2.17564 Journal of Bangladesh Academy of Scinces, Vol. 37, No. 2, 219-229, 2013
Thrombolytic activity of Coriandrum sativum
Authors: Shahriar Mohammad , Islam Md Siddiqul , Islam SM Ashraful , Parvin Salma , Afrin Nazia
Published: March 2014

The leaves of Coriandrum sativum were subjected to thrombolytic activities. The thrombolytic activities were assessed by using human blood samples and the results were compared with standard streptokinase (SK). In this study, the methanol soluble fraction (MSF) exhibited highest percentage of thrombolytic activity (60.12 ± 1.91). However, significant thrombolytic activity was demonstrated by the crude ethanol extract (CEE) and n-hexane soluble fraction (HSF) of C. sativum (45.85 ± 0.69) and (22.22 ± 1.42), respectively. DOI: http://dx.doi.org/10.3329/jbas.v37i2.17567 Journal of Bangladesh Academy of Scnces, Vol. 37, No. 2, 245-247, 2013
Critical Assessment of Theoretical Calculations of Atomic Structure and Transition Probabilities: An Experimenter’s View
Authors: Träbert Elmar
Published: March 2014

The interpretation of atomic observations by theory and the testing of computational predictions by experiment are interactive processes. It is necessary to gain experience with “the other side” before claims of achievement can be validated and judged. The discussion covers some general problems in the field as well as many specific examples, mostly organized by isoelectronic sequence, of what level of accuracy recently has been reached or which atomic structure or level lifetime problem needs more attention.
Stormwater Quality Characteristics in (Dutch) Urban Areas and Performance of Settlement Basins
Authors: Boogaard Floris , Van de Ven Frans , Langeveld Jeroen , Van de Giesen Nick
Published: March 2014

Stormwaters, flowing into storm sewers, are known to significantly increase the annual pollutant loads entering urban receiving waters and this results in significant degradation of the receiving water quality. Knowledge of the characteristics of stormwater pollution enables urban planners to incorporate the most appropriate stormwater management strategies to mitigate the effects of stormwater pollution on downstream receiving waters. This requires detailed information on stormwater quality, such as pollutant types, sediment particle size distributions, and how soluble pollutants and heavy metals attach themselves to sediment particles. This study monitored stormwater pollution levels at over 150 locations throughout the Netherlands. The monitoring has been ongoing for nearly 15 years and a total of 7,652 individual events have been monitored to date. This makes the database the largest stormwater quality database in Europe. The study compared the results to those presented in contemporary international stormwater quality research literature. The study found that the pollution levels at many of the Dutch test sites did not meet the requirements of the European Water Framework Directive (WFD) and Dutch Water Quality Standards. Results of the study are presented and recommendations are made on how to improve water quality with the implementation of Sustainable Urban Drainage Systems (SUDS) devices.
Mapping the Evolution of eLearning from 1977–2005 to Inform Understandings of eLearning Historical Trends
Authors: Sun Pei , Finger Glenn , Liu Zhen
Published: March 2014

While there have been very limited studies of the educational computing literature to analyze the research trends since the early emergence of educational computing technologies, the authors argue that it is important for both researchers and educators to understand the major, historical educational computing trends in order to inform understandings of current and future eLearning trends. This study provides the findings of an analysis of 2,694 journal articles published between 1977 and 2005 in four major, international educational computing journals. It provides the platform for a subsequent analysis for the period 2006–2014 and beyond, as future educational computing research is published. The journal articles analyzed were categorized according to their research themes. Subsequently, clustering analysis, multi-dimension scale analysis, and research diversity analysis were performed on the categorized results to explore the research trends. The research literature analysis confirmed that there were identifiable evolutionary trends dating from 1977, and, importantly, the analysis highlighted that each key breakthrough in technology was accompanied by increased educational research about those technologies to inform educational practices. Importantly, two major driving forces of the historical trends identified were technologies and pedagogical approaches. The paper concludes with explanations of how these trends from 1977–2005 have shaped the current focus on Technological Pedagogical Content Knowledge (TPACK) needed for effective current and future eLearning.
Effect of Ampicillin, Streptomycin, Penicillin and Tetracycline on Metal Resistant and Non-Resistant Staphylococcus aureus
Authors: Chudobova Dagmar , Dostalova Simona , Blazkova Iva , Michalek Petr , Ruttkay-Nedecky Branislav , Sklenar Matej , Nejdl Lukas , Kudr Jiri , Gumulec Jaromir , Tmejova Katerina , Konecna Marie , Vaculovicova Marketa , Hynek David , Masarik Michal , Kynicky Jindrich , Kizek Rene , Adam Vojtech
Published: March 2014

There is an arising and concerning issue in the field of bacterial resistance, which is confirmed by the number of deaths associated with drug-resistant bacterial infections. The aim of this study was to compare the effects of antibiotics on Staphylococcus aureus non-resistant strain and strains resistant to cadmium or lead ions. Metal resistant strains were created by the gradual addition of 2 mM solution of metal ions (cadmium or lead) to the S. aureus culture. An increasing antimicrobial effect of ampicillin, streptomycin, penicillin and tetracycline (0, 10, 25, 50, 75, 150, 225 and 300 µM) on the resistant strains was observed using a method of growth curves. A significant growth inhibition (compared to control) of cadmium resistant cells was observed in the presence of all the four different antibiotics. On the other hand, the addition of streptomycin and ampicillin did not inhibit the growth of lead resistant strain. Other antibiotics were still toxic to the bacterial cells. Significant differences in the morphology of cell walls were indicated by changes in the cell shape. Our data show that the presence of metal ions in the urban environment may contribute to the development of bacterial strain resistance to other substances including antibiotics, which would have an impact on public health.
A Tale of Two City Blocks: Differences in Immature and Adult Mosquito Abundances between Socioeconomically Different Urban Blocks in Baltimore (Maryland, USA)
Authors: Becker Brian , Leisnham Paul , LaDeau Shannon
Published: March 2014

Infrastructure degradation in many post-industrial cities has increased the availability of potential mosquito habitats, including container habitats that support infestations of invasive disease-vectors. This study is unique in examining both immature and adult mosquito abundance across the fine-scale variability in socio-economic condition that occurs block-to-block in many cities. We hypothesized that abundant garbage associated with infrastructure degradation would support greater mosquito production but instead, found more mosquito larvae and host-seeking adults (86%) in parcels across the higher socio-economic, low-decay block. Aedes albopictus and Culex pipiens were 5.61 (p < 0.001) and 4.60 (p = 0.001) times more abundant, respectively. Most discarded (garbage) containers were dry during peak mosquito production, which occurred during the 5th hottest July on record. Containers associated with human residence were more likely to hold water and contain immature mosquitoes. We propose that mosquito production switches from rain-fed unmanaged containers early in the season to container habitats that are purposefully shaded or watered by mid-season. This study suggests that residents living in higher socioeconomic areas with low urban decay may be at greater risk of mosquito-borne disease during peak mosquito production when local container habitats are effectively decoupled from environmental constraints.
Monitoring Geologic Hazards and Vegetation Recovery in the Wenchuan Earthquake Region Using Aerial Photography
Authors: Li Zhenwang , Jiao Quanjun , Liu Liangyun , Tang Huan , Liu Tong
Published: March 2014

On 12 May 2008, the 8.0-magnitude Wenchuan earthquake occurred in Sichuan Province, China, triggering thousands of landslides, debris flows, and barrier lakes, leading to a substantial loss of life and damage to the local environment and infrastructure. This study aimed to monitor the status of geologic hazards and vegetation recovery in a post-earthquake disaster area using high-resolution aerial photography from 2008 to 2011, acquired from the Center for Earth Observation and Digital Earth (CEODE), Chinese Academy of Sciences. The distribution and range of hazards were identified in 15 large, representative geologic hazard areas triggered by the Wenchuan earthquake. After conducting an overlay analysis, the variations of these hazards between successive years were analyzed to reflect the geologic hazard development and vegetation recovery. The results showed that in the first year after the Wenchuan earthquake, debris flows occurred frequently with high intensity. Resultantly, with the source material becoming less available and the slope structure stabilizing, the intensity and frequency of debris flows gradually decreased with time. The development rate of debris flows between 2008 and 2011 was 3% per year. The lithology played a dominant role in the formation of debris flows, and the topography and hazard size in the earthquake affected area also had an influence on the debris flow development process. Meanwhile, the overall geologic hazard area decreased at 12% per year, and the vegetation recovery on the landslide mass was 15% to 20% per year between 2008 and 2011. The outcomes of this study provide supporting data for ecological recovery as well as debris flow control and prevention projects in hazard-prone areas.
The Growth Hormone Secretagogue Receptor: Its Intracellular Signaling and Regulation
Authors: Yin Yue , Li Yin , Zhang Weizhen
Published: March 2014

The growth hormone secretagogue receptor (GHSR), also known as the ghrelin receptor, is involved in mediating a wide variety of biological effects of ghrelin, including: stimulation of growth hormone release, increase of food intake and body weight, modulation of glucose and lipid metabolism, regulation of gastrointestinal motility and secretion, protection of neuronal and cardiovascular cells, and regulation of immune function. Dependent on the tissues and cells, activation of GHSR may trigger a diversity of signaling mechanisms and subsequent distinct physiological responses. Distinct regulation of GHSR occurs at levels of transcription, receptor interaction and internalization. Here we review the current understanding on the intracellular signaling pathways of GHSR and its modulation. An overview of the molecular structure of GHSR is presented first, followed by the discussion on its signaling mechanisms. Finally, potential mechanisms regulating GHSR are reviewed.
Comparative Molecular Dynamics Simulations of Mitogen-Activated Protein Kinase-Activated Protein Kinase 5
Authors: Lindin Inger , Wuxiuer Yimingjiang , Ravna Aina , Moens Ugo , Sylte Ingebrigt
Published: March 2014

The mitogen-activated protein kinase-activated protein kinase MK5 is a substrate of the mitogen-activated protein kinases p38, ERK3 and ERK4. Cell culture and animal studies have demonstrated that MK5 is involved in tumour suppression and promotion, embryogenesis, anxiety, cell motility and cell cycle regulation. In the present study, homology models of MK5 were used for molecular dynamics (MD) simulations of: (1) MK5 alone; (2) MK5 in complex with an inhibitor; and (3) MK5 in complex with the interaction partner p38α. The calculations showed that the inhibitor occupied the active site and disrupted the intramolecular network of amino acids. However, intramolecular interactions consistent with an inactive protein kinase fold were not formed. MD with p38α showed that not only the p38 docking region, but also amino acids in the activation segment, αH helix, P-loop, regulatory phosphorylation region and the C-terminal of MK5 may be involved in forming a very stable MK5-p38α complex, and that p38α binding decreases the residual fluctuation of the MK5 model. Electrostatic Potential Surface (EPS) calculations of MK5 and p38α showed that electrostatic interactions are important for recognition and binding.
Phosphosite Mapping of HIP-55 Protein in Mammalian Cells
Authors: Liu Ning , Sun Ningning , Gao Xiang , Li Zijian
Published: March 2014

In the present study, hematopoietic progenitor kinase 1 (HPK1)-interacting protein of 55 kDa (HIP-55) protein was over-expressed in HEK293 cells, which was genetically attached with 6x His tag. The protein was purified by nickel-charged resin and was then subjected to tryptic digestion. The phosphorylated peptides within the HIP-55 protein were enriched by TiO2 affinity chromatography, followed by mass spectrometry analysis. Fourteen phosphorylation sites along the primary structure of HIP-55 protein were identified, most of which had not been previously reported. Our results indicate that bio-mass spectrometry coupled with manual interpretation can be used to successfully identify the phosphorylation modification in HIP-55 protein in HEK293 cells.
iNR-Drug: Predicting the Interaction of Drugs with Nuclear Receptors in Cellular Networking
Authors: Fan Yue-Nong , Xiao Xuan , Min Jian-Liang , Chou Kuo-Chen
Published: March 2014

Nuclear receptors (NRs) are closely associated with various major diseases such as cancer, diabetes, inflammatory disease, and osteoporosis. Therefore, NRs have become a frequent target for drug development. During the process of developing drugs against these diseases by targeting NRs, we are often facing a problem: Given a NR and chemical compound, can we identify whether they are really in interaction with each other in a cell? To address this problem, a predictor called “iNR-Drug” was developed. In the predictor, the drug compound concerned was formulated by a 256-D (dimensional) vector derived from its molecular fingerprint, and the NR by a 500-D vector formed by incorporating its sequential evolution information and physicochemical features into the general form of pseudo amino acid composition, and the prediction engine was operated by the SVM (support vector machine) algorithm. Compared with the existing prediction methods in this area, iNR-Drug not only can yield a higher success rate, but is also featured by a user-friendly web-server established at http://www.jci-bioinfo.cn/iNR-Drug/, which is particularly useful for most experimental scientists to obtain their desired data in a timely manner. It is anticipated that the iNR-Drug server may become a useful high throughput tool for both basic research and drug development, and that the current approach may be easily extended to study the interactions of drug with other targets as well.
Advances in a Distributed Approach for Ocean Model Data Interoperability
Authors: Signell Richard , Snowden Derrick
Published: March 2014

An infrastructure for earth science data is emerging across the globe based on common data models and web services. As we evolve from custom file formats and web sites to standards-based web services and tools, data is becoming easier to distribute, find and retrieve, leaving more time for science. We describe recent advances that make it easier for ocean model providers to share their data, and for users to search, access, analyze and visualize ocean data using MATLAB® and Python®. These include a technique for modelers to create aggregated, Climate and Forecast (CF) metadata convention datasets from collections of non-standard Network Common Data Form (NetCDF) output files, the capability to remotely access data from CF-1.6-compliant NetCDF files using the Open Geospatial Consortium (OGC) Sensor Observation Service (SOS), a metadata standard for unstructured grid model output (UGRID), and tools that utilize both CF and UGRID standards to allow interoperable data search, browse and access. We use examples from the U.S. Integrated Ocean Observing System (IOOS®) Coastal and Ocean Modeling Testbed, a project in which modelers using both structured and unstructured grid model output needed to share their results, to compare their results with other models, and to compare models with observed data. The same techniques used here for ocean modeling output can be applied to atmospheric and climate model output, remote sensing data, digital terrain and bathymetric data.
Influence of Molecular Conformations and Microstructure on the Optoelectronic Properties of Conjugated Polymers
Authors: Botiz Ioan , Stingelin Natalie
Published: March 2014

It is increasingly obvious that the molecular conformations and the long-range arrangement that conjugated polymers can adopt under various experimental conditions in bulk, solutions or thin films, significantly impact their resulting optoelectronic properties. As a consequence, the functionalities and efficiencies of resulting organic devices, such as field-effect transistors, light-emitting diodes, or photovoltaic cells, also dramatically change due to the close structure/property relationship. A range of structure/optoelectronic properties relationships have been investigated over the last few years using various experimental and theoretical methods, and, further, interesting correlations are continuously revealed by the scientific community. In this review, we discuss the latest findings related to the structure/optoelectronic properties interrelationships that exist in organic devices fabricated with conjugated polymers in terms of charge mobility, absorption, photoluminescence, as well as photovoltaic properties.
Fabricating Nanoporous Silica Structure on D-Fibres through Room Temperature Self-Assembly
Authors: Canning John , Moura Lucas , Lindoy Lachlan , Cook Kevin , Crossley Maxwell , Luo Yanhua , Peng Gang-Ding , Glavind Lars , Huyang George , Naqshbandi Masood , Kristensen Martin , Martelli Cicero , Town Graham
Published: March 2014

The room temperature deposition of self-assembling silica nanoparticles onto D-shaped optical fibres (“D-fibre”), drawn from milled preforms fabricated by modified chemical vapour deposition (MCVD), is studied. Vertical dip-and-withdraw produces tapered layers, with one end thicker (surface coverage >0.85) than the other, whilst horizontal dip-and-withdraw produces much more uniform layers over the core region. The propagation of induced fracturing over the core region during drying is overcome using a simple protrusion of the inner cladding. Thick coatings are discernible through thin film interference colouring, but thinner coatings require scanning electron microscopy (SEM) imaging. Here, we show that fluorescence imaging, using Rhodamine B, in this example, can provide some qualitative and speedy assessment of coverage.
Preparation of Poly(acrylic acid) Hydrogel by Radiation Crosslinking and Its Application for Mucoadhesives
Authors: Nho Young-Chang , Park Jong-Seok , Lim Youn-Mook
Published: March 2014

A mucoadhesive drug delivery system can improve the effectiveness of a drug by maintaining the drug concentration and allowing targeting and localization of the drug at a specific site. Acrylic-based hydrogels have been used extensively as a mucoadhesive system owing to their flexibility and excellent bioadhesion. In this experiment, poly(acrylic acid) was selected to prepare the bioadhesive hydrogel adhering to mucosal surfaces using a radiation process. Poly(acrylic acid) was dissolved in water to a prepare poly(acrylic acid) solution, and the solution was then irradiated by an electron beam at up to 75 kGy to make hydrogels. Their physical properties, such as gel percent, swelling percent and adhesive strength to mucosal surfaces, were investigated. Triamcinolone acetonide was used as a model drug. The dried poly(acrylic acid) film was dipped in a 0.1 wt% triamcinolone acetonide solution in ethanol, and then dried at 25 °C. The release of triamcinolone acetonide was determined at different time intervals, and UV (Ultraviolet)-Vis spectroscopy was used to determine the released concentration of triamcinolone acetonide at 238 nm. It was shown that poly(acrylic acid)-based drug carriers were successfully prepared for use in a bioadhesive drug delivery system.
An Innovative Curvelet-only-Based Approach for Automated Change Detection in Multi-Temporal SAR Imagery
Authors: Schmitt Andreas , Wessel Birgit , Roth Achim
Published: March 2014

This paper presents a novel approach for automated image comparison and robust change detection from noisy imagery, such as synthetic aperture radar (SAR) amplitude images. Instead of comparing pixel values and/or pre-classified features this approach clearly highlights structural changes without any preceding segmentation or classification step. The crucial point is the use of the Curvelet transform in order to express the image as composition of several structures instead of numerous individual pixels. Differentiating these structures and weighting their impact according to the image statistics produces a smooth, but detail-preserved change image. The Curvelet-based approach is validated by the standard technique for SAR change detection, the log-ratio with and without additional gamma maximum-a-posteriori (GMAP) speckle filtering, and by the results of human interpreters. The validation proves that the new technique can easily compete with these automated as well as visual interpretation techniques. Finally, a sequence of TerraSAR-X High Resolution Spotlight images of a factory building construction site near Ludwigshafen (Germany) is processed in order to identify single construction stages by the time of the (dis-)appearance of certain objects. Hence, the complete construction monitoring of the whole building and its surroundings becomes feasible.
Improved Algorithms for the Classification of Rough Rice Using a Bionic Electronic Nose Based on PCA and the Wilks Distribution
Authors: Xu Sai , Zhou Zhiyan , Lu Huazhong , Luo Xiwen , Lan Yubin
Published: March 2014

Principal Component Analysis (PCA) is one of the main methods used for electronic nose pattern recognition. However, poor classification performance is common in classification and recognition when using regular PCA. This paper aims to improve the classification performance of regular PCA based on the existing Wilks ?-statistic (i.e., combined PCA with the Wilks distribution). The improved algorithms, which combine regular PCA with the Wilks ?-statistic, were developed after analysing the functionality and defects of PCA. Verification tests were conducted using a PEN3 electronic nose. The collected samples consisted of the volatiles of six varieties of rough rice (Zhongxiang1, Xiangwan13, Yaopingxiang, WufengyouT025, Pin 36, and Youyou122), grown in same area and season. The first two principal components used as analysis vectors cannot perform the rough rice varieties classification task based on a regular PCA. Using the improved algorithms, which combine the regular PCA with the Wilks ?-statistic, many different principal components were selected as analysis vectors. The set of data points of the Mahalanobis distance between each of the varieties of rough rice was selected to estimate the performance of the classification. The result illustrates that the rough rice varieties classification task is achieved well using the improved algorithm. A Probabilistic Neural Networks (PNN) was also established to test the effectiveness of the improved algorithms. The first two principal components (namely PC1 and PC2) and the first and fifth principal component (namely PC1 and PC5) were selected as the inputs of PNN for the classification of the six rough rice varieties. The results indicate that the classification accuracy based on the improved algorithm was improved by 6.67% compared to the results of the regular method. These results prove the effectiveness of using the Wilks ?-statistic to improve the classification accuracy of the regular PCA approach. The results also indicate that the electronic nose provides a non-destructive and rapid classification method for rough rice.