bluuebunny/crossref_metadata_2025 huggingface dataset:
Matrix-filler interfaces and physical properties of metal matrix composites with negative thermal expansion manganese nitride
Authors: Takenaka Koshi , Kuzuoka Kota , Sugimoto Norihiro
Published: August 2015

Copper matrix composites containing antiperovskite manganese nitrides with negative thermal expansion (NTE) were formed using pulsed electric current sintering. Energy dispersive X-ray spectroscopy revealed that the chemically reacted region extends over 10 μm around the matrix–filler interfaces. The small-size filler was chemically deteriorated during formation of composites and it lost the NTE property. Therefore, we produced the composites using only the nitride particles having diameter larger than 50 μm. The large-size filler effectively suppressed the thermal expansion of copper and improved the conductivity of the composites to the level of pure aluminum. The present composites, having high thermal conductivity and low thermal expansion, are suitable for practical applications such as a heat radiation substrate for semiconductor devices.
Asymmetric director structures and flexoelectricity in nematic pi-cell devices
Authors: Tartan Chloe C. , Elston Steve J.
Published: August 2015

The sum of the flexoelectric coefficients in a liquid crystal material has been measured in nematic pi-cell devices, based on a method that exploits the asymmetry in the director configurations of the different states in a pi-cell, the uniform surface alignment polarities, and the influence of ions. A value of |e1 + e3| = 10 pC m−1 was measured from data-theory comparisons in the standard commercial eutectic E7 nematic liquid crystal mixture.
A novel microfluidic platform for studying mammalian cell chemotaxis in different oxygen environments under zero-flow conditions
Authors: Yang Wei , Luo Chunxiong , Lai Luhua , Ouyang Qi
Published: August 2015

The cell's micro-environment plays an important role in various physiological and pathological phenomena. To better investigate in vivo cellular behaviors, researchers have expended great effort in building controlled in vitro biophysical and biochemical environments. Because a cell's gaseous environment affects properties such as its division, metastasis, and differentiation, we developed a zero-flow based platform for studying mammalian cell chemotaxis behavior in different oxygen environments. This platform can construct a linear range of oxygen tensions within one chip (i.e., from 1.4% to 3.6% or 5.5% to 14.5%). To study cell chemotaxis behavior under varying oxygen environments, the chemical gradient direction is established perpendicularly to oxygen change within an observation area. Because the observation area is not subject to flow, shear force is of no concern. In addition, water flow around the cell chambers greatly reduces evaporation and makes long-term microscope imaging possible. In this study, we precisely measure the chemotaxis velocity of MCF-7 human breast cancer cells under different oxygen tension conditions towards CXCL12, which is a stromal cell-derived factor. We find that cell migration rates are not equivalent, even under two close oxygen tensions. We also observed that cells move faster towards high concentrations of chemoattractant when the oxygen tension is below 3% due to the increased expression of HIF-1 (hypoxia-inducible factor 1), which promotes a transition to the amoeboid rather than mesenchymal mode of movement. Our experiments demonstrate that this new microfluidic platform is useful for the quantitative study of mammalian cell chemotaxis under different oxygen conditions in the absence of shear force. We also shed light on the study of chemotaxis under other gaseous environments.
LaAlO3 thickness window for electronically controlled magnetism at LaAlO3/SrTiO3 heterointerfaces
Authors: Bi Feng , Huang Mengchen , Lee Hyungwoo , Eom Chang-Beom , Irvin Patrick , Levy Jeremy
Published: August 2015

Complex-oxide heterostructures exhibit rich physical behavior such as emergent conductivity, superconductivity, and magnetism that are intriguing for scientific reasons as well as for potential technological applications. It was recently discovered that in-plane magnetism at the LaAlO3/SrTiO3 (LAO/STO) interface can be electronically controlled at room temperature. Here, we employ magnetic force microscopy to investigate electronically controlled ferromagnetism at the LAO/STO interface with LAO thickness t varied from 4 unit cell (u.c.) to 40 u.c. Magnetic signatures are observed only within a thickness window 8 u.c. ≤ t ≤ 25 u.c. Within this window, the device capacitance corresponds well to the expected geometric value, while for thicknesses outside this window, the capacitance is strongly suppressed. The ability to modulate electronic and magnetic properties of LAO/STO devices depends on the ability to control carrier density, which is in turn constrained by intrinsic tunneling mechanisms.
Droplet formation and shrinking in aqueous two-phase systems using a membrane emulsification method
Authors: Breisig Hans , Wessling Matthias
Published: August 2015

Using a membrane emulsification method based on porous hollow-fiber membranes in combination with an aqueous two-phase system (ATPS), we are able to produce “water-in-water” droplets with narrow-dispersed size distributions. The equilibrium phases of the aqueous two-phase system polyethylene glycol-dipotassium hydrogen phosphate are used for this purpose. The droplet diameter of a given fluid system is determined by the flow rates of the continuous and disperse phase as well as the hollow fiber dimensions. When diluting the disperse phase and thus moving the ATPS system out of equilibrium, the droplet size can be further reduced in comparison to the equilibrium case. Generally, droplets formed with this method have diameters 20%–60% larger than the inner hollow fiber diameter. The new strategy of diluting the disperse phase allows the production of droplet diameter below the inner diameter of the membrane.
Kink and kink-like waves in pre-stretched Mooney-Rivlin viscoelastic rods
Authors: Wang Y. Z. , Dai H.-H. , Chen W. Q.
Published: August 2015

The present paper theoretically investigates kink and kink-like waves propagating in pre-stretched Mooney-Rivlin viscoelastic rods. In the constitutive modeling, the Cauchy stress tensor is assumed to consist of an elastic part and a dissipative part. The asymptotic method is adopted to simplify the nonlinear dynamic equations in the limit of finite-small amplitude and long wavelength. Using the reductive perturbation method, we further derive the well-known far-field equation (i.e. the KdV-Burgers equation), to which two kinds of explicit traveling wave solutions are presented. Examples are given to show the influences of pre-stretch and viscosity on the wave shape and wave velocity. It is shown that pre-stretch could be an effective method for modulating the two types of waves. In addition, such waves may be utilized to measure the viscosity coefficient of the material. The competition between the effects of pre-stretch and viscosity on the kink and kink-like waves is also revealed.
A novel 2nd-order bandpass MFSS filter with miniaturized structure
Authors: Fang C. Y. , Gao J. S. , Feng X. G.
Published: August 2015

In order to effectively obtain a miniaturized structure and good filtering properties, we propose a novel 2nd-order bandpass metamaterial frequency selective surface (MFSS) filter which contains two capacitive layers and one inductive layer, where there are multi-loop metallic patches as shunt capacitor C and planar wire grids as series inductor L respectively. Unlike the traditional operation way—the tuned elements used in resonant surface approximately equal to one wavelength in circumference and the structure thickness with a spacing of a quarter wavelength apart, by changing the value of L and C and matching multilayer dielectric to adjust the LC coupling resonance and the resonance impedance respectively, the proposed MFSS filter can achieves a miniatured structure with ideal bandpass properties. Measurement results of the fabricated prototype of the bandpass filter (BPF) indicate that the dimension of the tuned element on resonant surface is approximately 0.025 wavelength, i.e., 0.025λ. At the same time, the filter has the stable center frequency of f0 = 1.53GHz and the transmittance of T ⩾ 96.3% and high Q-value for the TE/TM wave polarization at various incidence angles. The novel 2nd-order bandpass MFSS filter with miniaturized structure not only can decrease structure dimension, but also has a wide range of applications to microwave and infrared band.
Phenology of two co-occurring Piper (Piperaceae) species in Brazil
Authors: Valentin-Silva Adriano , Vieira Milene F.
Published: August 2015

The co-occurrence of some species, including members of the Piper genus, has been shown to be associated with phenological factors. In the present study we analysed vegetative (sprout production and leaf flush) and reproductive phenophases (spike production, flowering, spike abortion, fruiting and dispersed spikes) of the co-occurring species Piper gaudichaudianum Kunth and Piper vicosanum Yunck. and checked the influence of abiotic factors on their phenological behaviour. Our study addressed natural populations in a semi-deciduous seasonal forest in south-eastern Brazil. In both species, the phenophases occurred mainly in the rainy season, were seasonal and associated with environmental variables, especially day length. However, sequential flowering and fruiting isolated them temporally from each other. Other differences were the growth of sexually reproductive sprouts (45.7% of the total sprouts) and the production of latent spikes in P. vicosanum; in P. gaudichaudianum, only 7.1% of the sprouts produced spikes that were not latent. Spike abortion was high: 73.8% (n = 474) in P. vicosanum and 84.8% (n = 231) in P. gaudichaudianum. The remaining spikes with fruits dispersed, on average, 293 and 1168 seeds per spike respectively. Although annual phenological behaviour of the species is regulated by similar environmental variables, their distinct reproductive strategies seem to favour the maintenance of the co-occurring populations.
Photodecarboxylative Benzylations of N-Methoxyphthalimide under Batch and Continuous-Flow Conditions
Authors: Pordanjani Hossein Mohammadkhani , Faderl Christian , Wang Jun , Motti Cherie A. , Junk Peter C. , Oelgemöller Michael
Published: August 2015

A series of photodecarboxylative benzylations of N-methoxyphthalimide were successfully realised using easily accessible starting materials. The reactions proceeded smoothly and the corresponding benzylated hydroxyphthalimidines were obtained in moderate to good yields of 52–73 %. No competing photoinduced dealkoxylation of the N-methoxy group was observed. The reaction with potassium phenylacetate was subsequently investigated in an advanced continuous-flow photoreactor. The reactor allowed rapid optimization of the reaction conditions and gave the desired benzylated product in higher yield and shorter irradiation time compared with the batch process.
Ecological effects of game management: does supplemental feeding affect herbivory pressure on native vegetation?
Authors: Miranda María , Cristóbal Ignacio , Díaz Leticia , Sicilia Marisa , Molina-Alcaide Eduarda , Bartolomé Jordi , Fierro Yolanda , Cassinello Jorge
Published: August 2015

Context Supplemental feeding of large mammalian herbivores is a common management tool mainly aimed at promoting healthy populations and at increasing productivity and trophy sizes. Such management measure may indirectly affect herbivore effects on plant communities through altered foraging patterns. The quantification of the ecological effects of large herbivore management is important for designing holistic management and conservation programs. Aims Here we aimed at quantifying the ecological effects of supplemental feeding of Iberian red deer, Cervus elaphus hispanicus, on the composition of and on the browsing effects on Mediterranean woody plant community. Methods An experiment was set up in a hunting rangeland located in central Spain, where female deer were kept in enclosures with either exclusive access to natural forages or with additional ad libitum access to a nutritionally rich concentrate. The experiment also included a control area where deer were absent. Key results We observed significant differences in browsing impacts among the supplemented, non-supplemented and control areas, and such effect varied for the different plant species. Plant species which nutritional content complemented that of fodder were more highly consumed, for instance, Erica spp., which digestible fibre content is higher and N content lower than that of provided fodder. The presence of deer and the concentrate supplied, instead, did not influence the relative abundances of shrub species. Conclusions Artificial supplemental feeding provided to ungulates led to increased browsing on plant species which nutritional composition complemented that of the supplement provided. Implications So as to alleviate herbivory impact on all shrubs, we suggest that composition of supplemental feeding should adjust both to the natural forage availability and quality and to ungulate requirements across seasons.
An effective attentional set for a specific colour does not prevent capture by infrequently presented motion distractors
Authors: Retell James D. , Becker Stefanie I. , Remington Roger W.
Published: August 2015

An organism's survival depends on the ability to rapidly orient attention to unanticipated events in the world. Yet, the conditions needed to elicit such involuntary capture remain in doubt. Especially puzzling are spatial cueing experiments, which have consistently shown that involuntary shifts of attention to highly salient distractors are not determined by stimulus properties, but instead are contingent on attentional control settings induced by task demands. Do we always need to be set for an event to be captured by it, or is there a class of events that draw attention involuntarily even when unconnected to task goals? Recent results suggest that a task-irrelevant event will capture attention on first presentation, suggesting that salient stimuli that violate contextual expectations might automatically capture attention. Here, we investigated the role of contextual expectation by examining whether an irrelevant motion cue that was presented only rarely (∼3–6% of trials) would capture attention when observers had an active set for a specific target colour. The motion cue had no effect when presented frequently, but when rare produced a pattern of interference consistent with attentional capture. The critical dependence on the frequency with which the irrelevant motion singleton was presented is consistent with early theories of involuntary orienting to novel stimuli. We suggest that attention will be captured by salient stimuli that violate expectations, whereas top-down goals appear to modulate capture by stimuli that broadly conform to contextual expectations.
Hydromonas duriensis gen. nov., sp. nov., isolated from freshwater
Authors: Vaz-Moreira Ivone , Narciso-da-Rocha Carlos , De Brandt Evie , Vandamme Peter , Silva Ferreira A. C. , Lobo-da-Cunha Alexandre , Nunes Olga C. , Manaia Célia M.
Published: August 2015

An aerobic, Gram-stain-negative rod, designated strain A2P5T, was isolated from the Douro river, in Porto, Portugal. Cells were catalase- and oxidase-positive. Growth occurred at 15–30 °C, at pH 6–8 and in the presence of 1 % (w/v) NaCl. The major respiratory quinone was Q8, the genomic DNA had a G+C content of 47 ± 1 mol%, and phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol were amongst the major polar lipids. On the basis of 16S rRNA gene sequence analysis, strain A2P5T was observed to be a member of the family Burkholderiaceae, but could not be identified as a member of any validly named genus. The low levels of 16S rRNA gene sequence similarity to other recognized taxa ( < 91 %), together with the comparative analysis of phenotypic and chemotaxonomic characteristics, supported the proposal of a novel species of a new genus within the family Burkholderiaceae. The name Hydromonas duriensis gen. nov., sp. nov. is proposed. The type strain of Hydromonas duriensis is A2P5T ( = LMG 28428T = CCUG 66137T).
Hymenobacter mucosus sp. nov., isolated from a karst cave soil sample
Authors: Liu Lan , Zhou En-Min , Jiao Jian-Yu , Manikprabhu Deene , Ming Hong , Huang Mei-Juan , Yin Yi-Rui , Li Wen-Jun
Published: August 2015

A novel Gram-stain-negative, non-motile, rod-shaped and watermelon-red-pigmented aerobic bacterial strain, designated YIM 77969T, was isolated from a soil sample of Jiuxiang cave, a tourism cave located in Yiliang county, Yunnan province, south-west China. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that strain YIM 77969T belongs to the genus Hymenobacter, and was closely related to Hymenobacter tibetensis XTM003T (96.58 %), Hymenobacter gelipurpurascens Txg1T (96.02 %) and Hymenobacter xinjiangensis X2-1gT (95.80 %). Growth of strain YIM 77969T occurred at 5–35 °C, at pH 5.0–9.0 and in the presence of 0–1 % (w/v) NaCl. The predominant menaquinone was MK-7. The major fatty acids were iso-C15 : 0, C16 : 1ω5c and summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c). The polar lipid profiles consisted of the major compound phosphatidylethanolamine, two unknown aminolipids, three unknown aminophospholipids, one glycolipid and one unknown polar lipid. Pigment analysis showed that the pigment belonged to the plectaniaxanthin series of carotenoid pigments. The genomic DNA G+C content was 55.2 mol%. On the basis of phylogenetic, phenotypic and chemotaxonomic characteristics, strain YIM 77969T is considered to represent a novel species of the genus Hymenobacter, for which the name Hymenobacter mucosus sp. nov. is proposed. The type strain is YIM 77969T ( = KCTC 32567T = DSM 28041T).
Georgenia subflava sp. nov., isolated from a deep-sea sediment
Authors: Wang Shuang , Xu Xianzhong , Wang Lina , Jiao Kailin , Zhang Gaiyun
Published: August 2015

A Gram-stain-positive, aerobic, motile and non-spore-forming actinobacterium, strain Y32T, was isolated from a deep-sea sediment of the western Pacific Ocean. Phylogenetic and phenotypic properties of the organism supported that it belonged to the genus Georgenia. Strain Y32T shared highest 16S rRNA gene sequence similarity of 97.8 % with Georgenia muralis 1A-CT, followed by Georgenia thermotolerans TT02-04T (97.4 %), Georgenia daeguensis 2C6-43T (97.2 %), Oceanitalea nanhaiensis JLT1488T (97.2 %), Georgenia ruanii YIM 004T (97.0 %) and Georgenia soli CC-NMPT-T3T (97.0 %). The organism grew in the presence of 0–10 % (w/v) NaCl, at 4–40 °C and at pH 6–11, with optimal growth occurring at 30–35 °C, at pH 7 and in the presence of 3.5 % (w/v) NaCl. The polar lipid profile of strain Y32T consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and two phosphatidylinositol mannosides. Strain Y32T contained MK-8(H4) and MK-7(H4) as the major components of the menaquinone system, and anteiso-C15 : 0, iso-C15 : 0 and iso-C14 : 0 as the predominant fatty acids. Galactose was detected as the cell-wall sugar. The G+C content of the DNA was 71.2 mol%. Based on the results of phenotypic, genotypic and phylogenetic analyses, it is considered that strain Y32T represents a novel species of the genus Georgenia, for which the name Georgenia subflava sp. nov. is proposed. The type strain is Y32T ( = LMG 28101T = CGMCC 1.12782T = JCM 19765T = MCCC 1A09955T).
Marinibacterium profundimaris gen. nov., sp. nov., isolated from deep seawater
Authors: Li Guizhen , Lai Qiliang , Du Yaping , Liu Xiupian , Sun Fengqin , Shao Zongze
Published: August 2015

A taxonomic study was carried out on strain 22II1-22F33T, which was isolated from deep seawater of the Atlantic Ocean. The bacterium was Gram-stain-negative, oxidase-positive and weakly catalase-positive, oval in shape without flagellum. Growth was observed at salinities of 0–12 % and at temperatures of 4–41 °C. The isolate was capable of hydrolysing aesculin and Tween 80 and reduction of nitrate to nitrite, but unable to hydrolyse gelatin. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain 22II1-22F33T belongs to the family Rhodobacteraceae, with highest sequence similarity to Pseudooceanicola marinus AZO-CT (96.5 %). The principal fatty acids (>10 %) were summed feature 8 (C18 : 1ω7c/ω6c) (73.8 %). The G+C content of the genomic DNA was 66.2 mol%. The respiratory quinone was Q-10 (100 %). Phosphatidylethanolamine (PE), phosphatidylglycerol (PG), phosphatidylcholine (PC), two unidentified aminolipids (ALs), six unidentified phospholipids (PLs) and one unidentified lipid (L) were present. The combined genotypic and phenotypic data show that strain 22II1-22F33T represents a novel species within a new genus, for which the name Marinibacterium profundimaris gen. nov., sp. nov. is proposed. The type strain of Marinibacterium profundimaris is 22II1-22F33T ( = LMG 27151T = MCCC 1A09326T).
Celeribacter manganoxidans sp. nov., a manganese-oxidizing bacterium isolated from deep-sea sediment of a polymetallic nodule province
Authors: Wang Long , Liu Yan , Wang Yanan , Dai Xiaofeng , Zhang Xiao-Hua
Published: August 2015

A Gram-stain-negative, strictly aerobic, non-motile, rod-shaped, manganese-oxidizing bacterial strain, designated DY2–5T, was isolated from surface sediment of Pacific Clarion-Clipperton Fracture Zone (CCFZ). Growth occurred at 0–37 °C (optimum 28 °C), pH 6.5–9.0 (optimum pH 7.0–7.5) and in the presence of 1–11 % (w/v) NaCl (optimum 3–4 %). Phylogenetic analysis based on 16S rRNA gene sequences revealed that the novel strain was most closely related to Celeribacter halophilus ZXM137T with 96.13 % sequence similarity, and had 16S rRNA gene sequence similarities in the range 93.89–95.87 % with other species of the genus Celeribacter. The dominant fatty acids were summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c) and C16 : 0. The polar lipids of strain DY2–5T comprised phosphatidylglycerol, phosphatidylcholine and two unknown aminolipids. The major respiratory quinone was ubiquinone–10 (Q–10). The DNA G+C content of strain DY2–5T was 64.8 mol%. On the basis of the phenotypic, genotypic and physiological evidence, strain DY2–5T represents a novel species of the genus Celeribacter, for which the name Celeribacter manganoxidans sp. nov. is proposed. The type strain is DY2–5T ( = JCM 19384T = KCTC 32473T).
Cell-cell communication enhances the capacity of cell ensembles to sense shallow gradients during morphogenesis
Authors: Ellison David , Mugler Andrew , Brennan Matthew , Lee Sung Hoon , Huebner Robert , Shamir Eliah , Woo Laura A. , Kim Joseph , Amar Patrick , Nemenman Ilya , Ewald Andrew J. , Levchenko Andre
Published: August 2015

Abstract

Collective cell responses to exogenous cues depend on cell-cell interactions. In principle, these can result in enhanced sensitivity to weak and noisy stimuli. However, this has not yet been shown experimentally, and, little is known about how multicellular signal processing modulates single cell sensitivity to extracellular signaling inputs, including those guiding complex changes in the tissue form and function. Here we explored if cell-cell communication can enhance the ability of cell ensembles to sense and respond to weak gradients of chemotactic cues. Using a combination of experiments with mammary epithelial cells and mathematical modeling, we find that multicellular sensing enables detection of and response to shallow Epidermal Growth Factor (EGF) gradients that are undetectable by single cells. However, the advantage of this type of gradient sensing is limited by the noisiness of the signaling relay, necessary to integrate spatially distributed ligand concentration information. We calculate the fundamental sensory limits imposed by this communication noise and combine them with the experimental data to estimate the effective size of multicellular sensory groups involved in gradient sensing. Functional experiments strongly implicated intercellular communication through gap junctions and calcium release from intracellular stores as mediators of collective gradient sensing. The resulting integrative analysis provides a framework for understanding the advantages and limitations of sensory information processing by relays of chemically coupled cells.
A structural hierarchy mediated by multiple nuclear factors establishes IgH locus conformation
Authors: Gerasimova Tatiana , Guo Changying , Ghosh Amalendu , Qiu Xiang , Montefiori Lindsey , Verma-Gaur Jiyoti , Choi Nancy M. , Feeney Ann J. , Sen Ranjan
Published: August 2015

Conformation of antigen receptor gene loci spatially juxtaposes rearranging gene segments in the appropriate cell lineage and developmental stage. We describe a three-step pathway that establishes the structure of the 2.8-Mb immunoglobulin heavy chain gene (IgH) locus in pro-B cells. Each step uses a different transcription factor and leads to increasing levels of structural organization. CTCF mediates one level of compaction that folds the locus into several 250- to 400-kb subdomains, and Pax5 further compacts the 2-Mb region that encodes variable (VH) gene segments. The 5′ and 3′ domains are brought together by the transcription factor YY1 to establish the configuration within which gene recombination initiates. Such stepwise mechanisms may apply more generally to establish regulatory fine structure within megabase-sized topologically associated domains.
Cocrystals of 2,6-dichloroaniline and 2,6-dichlorophenol plus three new pseudopolymorphs of their coformers
Authors: Gerhardt Valeska , Bolte Michael
Published: August 2015

The structures of cocrystals of 2,6-dichlorophenol with 2,4-diamino-6-methyl-1,3,5-triazine, C6H4Cl2O·C4H7N5, (III), and 2,6-dichloroaniline with 2,6-diaminopyrimidin-4(3H)-one andN,N-dimethylacetamide, C6H5Cl2N·C4H6N4O·C4H9NO, (V), plus three new pseudopolymorphs of their coformers, namely 2,4-diamino-6-methyl-1,3,5-triazine–N,N-dimethylacetamide (1/1), C4H7N5·C4H9NO, (I), 2,4-diamino-6-methyl-1,3,5-triazine–N-methylpyrrolidin-2-one (1/1), C4H7N5·C5H9NO, (II), and 6-aminoisocytosine–N-methylpyrrolidin-2-one (1/1), C4H6N4O·C5H9NO, (IV), are reported. Both 2,6-dichlorophenol and 2,6-dichloroaniline are capable of forming definite synthon motifs, which usually lead to either two- or three-dimensional crystal-packing arrangements. Thus, the two isomorphous pseudopolymorphs of 2,4-diamino-6-methyl-1,3,5-triazine,i.e.(I) and (II), form a three-dimensional network, while theN-methylpyrrolidin-2-one solvate of 6-aminoisocytosine,i.e.(IV), displays two-dimensional layers. On the basis of these results, attempts to cocrystallize 2,6-dichlorophenol with 2,4-diamino-6-methyl-1,3,5-triazine, (III), and 2,6-dichloroaniline with 6-aminoisocytosine, (V), yielded two-dimensional networks, whereby in cocrystal (III) the overall structure is a consequence of the interaction between the two compounds. By comparison, cocrystal–solvate (V) is mainly built by 6-aminoisocytosine forming layers, with 2,6-dichloroaniline and the solvent molecules arranged between the layers.
Agricultural credit and economic growth in rural areas
Authors: Hartarska Valentina , Nadolnyak Denis , Shen Xuan
Published: August 2015

Purpose

– In this paper, the authors set out to establish if there is a link between finance and economic growth in rural areas. The purpose of this paper is to evaluate the relation between credit by major lenders in rural areas – commercial banks and Farm Credit System (FCS) institutions – and economic growth for the period 1991-2010.

Design/methodology/approach

– The motivation for this work comes from empirical studies showing a link between economic development and financial system development as well as from work which highlights the positive role of long-term finance provided by banks. The authors use two alternative panel data sets and fixed effects models to estimate the causal effect of credit supply (with lagged explanatory variables) on agricultural GDP growth per rural resident.

Findings

– The authors find a positive association between agricultural lending and agricultural GDP growth per rural resident with additional billion in loans (about a third of the actual average) associated with 7-10 percent higher state growth rate with this association stronger during the 1990s. Regional data confirm these results. The results point to a positive link between credit and economic growth in rural areas during that period, attributable to the lending by FCS institutions and by commercial banks.

Research limitations/implications

– Data availability limits the scope of this paper. The authors use state level balance sheet data available for the 1991-2003 period and annual data for 2003-2010 period. An additional regional data set is constructed for 1991-2010 with more aggregated data for the ten USDA agricultural production regions. The small number of panels limits the ability to use more sophisticated econometric models and the choice of dependent variables that captures economic growth.

Practical implications

– By provides evidence that agricultural finance and in particular lending contribute significantly to the growth of US agriculture, this paper contributes to the policy debate on weather support for agricultural finance initiatives is justified.

Originality/value

– The authors are not aware of another study that has linked agricultural lending by commercial banks and FCS institutions to growth in rural areas in the USA.
Does federal crop insurance lead to higher farm debt use? Evidence from the Agricultural Resource Management Survey (ARMS)
Authors: Ifft Jennifer E , Kuethe Todd , Morehart Mitch
Published: August 2015

Purpose

– The purpose of this paper is to consider how the federal crop insurance (FCI) program influences farm debt use, one of the key financial decisions made by farm operators.

Design/methodology/approach

– Using data from the nationally representative Agricultural Resource Management Survey, the paper implements a propensity score matching model of the impact of FCI participation on various measures of farm business debt use. To account for the simultaneity of financial decisions, the paper further tests this relationship using a seemingly unrelated regression model.

Findings

– FCI participation is associated with an increase in use of short-term farm debt, but not long-term debt, consistent with risk balancing behavior and current trends in the farm sector.

Research limitations/implications

– In addition to risk balancing, the results are also consistent with credit constraints or lender preferences. The paper cannot fully establish causality between crop insurance participation and short-term debt levels. Future research should address these limitations.

Practical implications

– Agricultural lending standards are generally conservative and the farm sector as a whole currently has historically low leverage, which implies that an increase in debt use may not be a threat to the financial health of the farm sector.

Social implications

– The results indicate that the reduction in total risk facing the farm sector is significantly less than the decline in risk provided by FCI, which is an important consideration for policymakers.

Originality/value

– This is the first paper to use an econometric model to analyze the relationship between FCI and farm debt use decisions. This paper can inform future research on the FCI program and farm financial decisions.
Geographical diversification in wheat farming: a copula-based CVaR framework
Authors: Larsen Ryan , Leatham David , Sukcharoen Kunlapath
Published: August 2015

Purpose

– Portfolio theory suggests that geographical diversification of production units could potentially help manage the risks associated with farming, yet little research has been done to evaluate the effectiveness of a geographical diversification strategy in agriculture. The paper aims to discuss this issue.

Design/methodology/approach

– The paper utilizes several tools from modern finance theory, including Conditional Value-at-Risk (CVaR) and copulas, to construct a model for the evaluation of a diversification strategy. The proposed model – the copula-based mean-CVaR model – is then applied to the producer’s acreage allocation problem to examine the potential benefits of risk reduction from a geographical diversification strategy in US wheat farming. Along with the copula-based model, the multivariate-normal mean-CVaR model is also estimated as a benchmark.

Findings

– The mean-CVaR optimization results suggest that geographical diversification is a viable risk management strategy from a farm’s profit margin perspective. In addition, the copula-based model appears more appropriate than the traditional multivariate-normal model for conservative agricultural producers who are concerned with the extreme losses of farm profitability in that the later model tends to underestimate the minimum level of risk faced by the producers for a given level of profitability.

Originality/value

– The effectiveness of geographical diversification in US wheat farming is evaluated. As a methodological contribution, the copula approach is used to model the joint distribution of profit margins and CVaR is employed as a measure of downside risk.
A field study for assessing risk-contingent credit for Kenyan pastoralists and dairy farmers
Authors: Shee Apurba , Turvey Calum G. , Woodard Joshua
Published: August 2015

Purpose

– The purpose of this paper is to assess the feasibility of risk-contingent credit (RCC) by presenting an experimental and participatory game designed to explain the concept of RCC to Kenyan pastoralists and dairy farmers. The paper investigates the uptake potential of RCC through qualitative assessment of field experiments and focus groups.

Design/methodology/approach

– The paper presents a method of community engagement through a participatory game played in a series of Focus Group Discussions (FGDs). The paper also presents theoretical justification of RCC in credit market structure.

Findings

– The game effectively explains the concept and mechanism of RCC by reflecting local situation and production potential. Participatory exercises within focus group discussions indicate that there exists a strong interest and support for RCC.

Research limitations/implications

– The methodology described in this paper can be used in extension programs for promoting innovative rural microcredit in developing countries but should be modified according to the local production and associated weather and market risks.

Originality/value

– Micro-insurance and credit program delivery can be improved by the innovative approach of community engagement for explaining financial products.
Structural mapping of public distribution system using multi-agent systems
Authors: Ambekar Sudhir , Kapoor Rohit , Mehta Peeyush
Published: August 2015

Purpose

– The purpose of this paper is to develop a framework for mapping the Indian Public Distribution System (PDS) using multi-agent system (MAS). The entire PDS supply chain from purchase to the distribution is mapped in detail by integrating stages of PDS supply chain.

Design/methodology/approach

– Literature related to PDS, food grain supply chain (FGSC) and MAS is reviewed and critically assessed. Based on this a framework is proposed which will help in improving functioning of PDS.

Findings

– The PDS has many shortcomings arising from its complex structure and practices which are used to implement it. The authors propose an MAS to model it in which each entity will be modelled as an agent. The authors propose two stages of supply chain. First stage models the processes from procurement to storage of food grain and second stage model the distribution process.

Practical implications

– This paper will be of interest to the policy makers and decision makers involved in the PDS by providing the shortfalls in the system and also suggesting a method to model the PDS based on practices of food supply chains.

Originality/value

– This paper provides the decision makers in the PDS, a framework to model and assess the entire supply chain. This will help them in effective implementation of the PDS and also improve in the areas of concerns which are pointed the study.
Patient-journey modelling and simulation in computed tomography
Authors: Samaranayake Premaratne , Dadich Ann , Hayes Kate J , Sloan Terrence
Published: August 2015

Purpose

– The purpose of this paper is to present a business process reengineering (BPR) framework of process and data integration with patient journey as the basis for process evaluation and the improvement of patient-flow.

Design/methodology/approach

– A BPR framework is developed using a mixed-method research design, which incorporated a case study to demonstrate a healthcare scenario with associated processes and data elements, using process models based on event-driven process chain methodology as well as patient and data models, based on unitary structuring technique. The framework includes key processes including patient booking and rebooking, and associated inputs, outputs, and control parameters. In this case, the framework is demonstrated through application to computed tomography (CT) services in a hospital to improve patient-flow, with numerical simulation of CT data collected over time.

Findings

– The framework supports flexible patient scheduling and the associated planning of healthcare operations and logistics – this in turn helps to improve patient-flow. Furthermore, mathematical modelling and simulation precisely reveal the impact of booking and rebooking on the performance of the CT department.

Research limitations/implications

– This innovative framework has potential value for other services, within and beyond the hospital setting.

Originality/value

– The proposed framework of process modelling, data, and patient journey addresses the lack of a holistic approach to monitoring and evaluating service performance in hospital settings. Patient journey modelling is an integral part of process and data models that can be implemented in an integrated system environment such as an enterprise resource planning system for real-time monitoring of patient-flow under dynamic conditions.
College students’ awareness in organizational strategy use in English writing
Authors: Chien Shih-Chieh
Published: August 2015

Purpose

– The purpose of the study is to look at Chinese English as a foreign language (EFL) learners’ organizational strategy use in English writing at universities in Taiwan. One significant area that has been indicated in contrastive rhetoric studies spins around the notion of culturally constructed organizational patterns. It is claimed that second language (L2) writers may have implicit culturally driven presuppositions and values about academic writing in the first language (L1) that may transfer straightforwardly to academic writing in English.

Design/methodology/approach

– Data were from 50 high- and 50 low-achieving EFL students’ and 50 native English speakers’ (NESs’) written texts, and semi-structured interviews with EFL students and their teachers.

Findings

– Based on text analysis, when high-achieving EFL students and NESs were compared, they were similar in location of thesis, existence of introduction, existence of topic sentences, macro-level patterns, existence of conclusion, existence of a concluding sentence and existence of a final comment, but different in existence of background information. Nonetheless, it is noted that low-achieving EFL students were quite different from high-achieving EFL students and NESs in several aspects, such as location of thesis, existence of introduction, existence of topic sentences, macro-level patterns, existence of conclusion, existence of a concluding sentence, and existence of a final comment. In addition, the written texts and interview findings suggest that while cultural differences do, in fact, exist, Chinese writers’ English organizational strategy use were to some extent intertwined with their writing experiences and teachers’ writing instructions. The results also suggest the flexibility of writers and multiplicity of writing experiences within a cultural group.

Originality/value

– The study makes original recommendations for language pedagogy.
Teaching spoken English in Iran’s private language schools: issues and options
Authors: Sadeghi Karim , Richards Jack C.
Published: August 2015

Purpose

– Mastery of spoken English is a priority for many learners of English in Iran. Opportunities to acquire spoken English through the public school system are very limited, hence many students enroll in “conversation” courses in private institutes. The purpose of this paper is to report a study of how institute teachers address the teaching of spoken English.

Design/methodology/approach

– Eighty-nine teachers completed a questionnaire on how they teach spoken English. The information was supplemented with interviews and classroom observation.

Findings

– Results suggest that institute courses reflect a poor understanding of the nature of spoken interaction, which is reflected in speaking courses that are unfocused and that do not address key aspects of conversational interaction.

Practical implications

– Suggestions are given for a re-examination of the differences between “conversation” and “discussion” in spoken English classes as the basis for designing spoken English classes and materials, as well as for the use of out-of-class learning opportunities to enhance the learning of spoken English in Iran and elsewhere.

Originality/value

– This paper is based on the authors’ original research, and the authors believe this is the first study of its kind in the Iranian context.
Gender perspectives on university education and entrepreneurship
Authors: Tegtmeier Silke , Mitra Jay
Published: August 2015

Purpose

– The purpose of this paper is to direct attention to recent research on women’s entrepreneurship with a focus on university education. A literature review and a summary of authors’ selected papers provide both a context for and an introduction to the articles in this special issue.

Design/methodology/approach

– This introduction provides an overview of the literature on female entrepreneurship with specific reference to the context of university education. Searches on Web of Science and in this journal were conducted to provide a systematic overview of the area of research. This introductory article ends with a set of propositions for future research engagement.

Findings

– This paper finds that the quantum of past research endeavours remains limited despite the growing significance of the subject. This paper also finds that developing a focused approach that is based on a female ontology of entrepreneurship, and one that identifies specific contexts, and appropriate methodological considerations that enable enquiry at different levels, are of value to future research. This paper offers four different propositions that address key areas or fields of entrepreneurship research.

Research limitations/implications

– This paper provides a unique set of propositions together with a framework which helps to both explore new knowledge creation and locate new research within the main fields of entrepreneurship while providing room for extending those fields.

Practical implications

– This overview provides a framework for universities and policymakers to enable them to take into consideration the critical issues of entrepreneurship in general, and female entrepreneurship in particular, when developing programmes and tools for university education.

Originality/value

– This paper provides a summary of the trends in research on women’s entrepreneurship with reference to university education. This leads to the development of a set of propositions and a framework for identifying and exploring new research questions that need to be addressed to close important research gaps in the field of entrepreneurship.
Investigation of oxygen followed by argon plasma treatment on LED chip bond pad for wire bond application
Authors: Peng Hui Yuen , Devarajan Mutharasu , Lee Teik Toon , Lacey David
Published: August 2015

Purpose

– The purpose of this paper is to investigate the efficiencies of argon (Ar), oxygen (O2) and O2 followed by Ar (O2→Ar) plasma treatments in terms of contaminant removal and wire bond interfacial adhesion improvement. The aim of this study is to resolve the “lifted ball bond” issue, which is one of the critical reliability checkpoints for light emitting diodes (LEDs) in automotive applications.

Design/methodology/approach

– Ar, O2 and O2→Ar plasma treatments were applied to LED chip bond pad prior to wire bonding process with different treatment durations. Various surface characterization methods and contact angle measurement were then used to characterize the surface properties of these chip bond pads. To validate the improvements of Ar, O2 and O2→Ar plasma treatments to the wire bond interfacial adhesion, the chip bond pads were wire bonded and examined with a ball shear test. Moreover, the contact resistance of the wire bond interfaces was also measured by using four-point probe electrical measurements to complement the interfacial adhesion validation.

Findings

– Surface characterization results show that O2→Ar plasma treatment was able to remove the contaminant while maintaining relatively low oxygen impurity content on the bond pad surface after the treatment and was more effective as compared with the O2 and Ar plasma treatments. However, O2→Ar plasma treatment also simultaneously reduced high-polarity bonds on the chip bond pad, leading to a lower surface free energy than that with the O2 plasma treatment. Ball shear test and contact resistance results showed that wire bond interfacial adhesion improvement after the O2→Ar plasma treatment is lower than that with the O2 plasma treatment, although it has the highest efficiency in surface contaminant removal.

Originality/value

– To resolve “lifted ball bond” issue, optimization of plasma gas composition ratios and parameters for respective Ar and O2 plasma treatments has been widely reported in many literatures; however, the O2→Ar plasma treatment is still rarely focused. Moreover, the observation that wire bond interfacial adhesion improvement after O2→Ar plasma treatment is lower than that with the O2 plasma treatment although it has the highest efficiency in surface contaminant removal also has not been reported on similar studies elsewhere.
Recent advances in mechanical properties of anisotropic conductive adhesive film for microelectronic packaging
Authors: Gao Lilan , Gao Hong , Chen Xu
Published: August 2015

Purpose

– This review paper aims to provide a better understanding of formulation and processing of anisotropic conductive adhesive film (ACF) material and to summarize the significant research and development work for the mechanical properties of ACF material and joints, which helps to the development and application of ACF joints with better reliability in microelectronic packaging systems.

Design/methodology/approach

– The ACF material was cured at high temperature of 190°C, and the cured ACF was tested by conducting the tensile experiments with uniaxial and cyclic loads. The ACF joint was obtained with process of pre-bonding and final bonding. The impact tests and shear tests of ACF joints were completed with different aging conditions such as high temperature, thermal cycling and hygrothermal aging.

Findings

– The cured ACF exhibited unique time-, temperature- and loading rate-dependent behaviors and a strong memory of loading history. Prior stress cycling with higher mean stress or stress amplitude restrained the ratcheting strain in subsequent cycling with lower mean stress or stress amplitude. The impact strength and adhesive strength of ACF joints increased with increase of bonding temperature, but they decreased with increase of environment temperature. The adhesive strength and life of ACF joints decreased with hygrothermal aging, whereas increased firstly and then decreased with thermal cycling.

Originality/value

– This study is to review the recent investigations on the mechanical properties of ACF material and joints in microelectronic packaging applications.