bluuebunny/crossref_metadata_2025 huggingface dataset:
The expressions of MIF and CXCR4 protein in tumor microenvironment are adverse prognostic factors in patients with esophageal squamous cell carcinoma
Authors: Zhang Lin , Ye Shu-Biao , Ma Gang , Tang Xiao-Feng , Chen Shi-Ping , He Jia , Liu Wan-Li , Xie Dan , Zeng Yi-Xin , Li Jiang
Published: March 2013

Background

Tumor-derived cytokines and their receptors usually take important roles in the disease progression and prognosis of cancer patients. In this survey, we aimed to detect the expression levels of MIF and CXCR4 in different cell populations of tumor microenvironments and their association with survivals of patients with esophageal squamous cell carcinoma (ESCC).

Methods

MIF and CXCR4 levels were measured by immunochemistry in tumor specimens from 136 resected ESCC. Correlation analyses and independent prognostic outcomes were determined using Pearson’s chi-square test and Cox regression analysis.

Results

The expression of CXCR4 in tumor cells was positively associated with tumor status (P = 0.045) and clinical stage (P = 0.044); whereas the expression of CXCR4 in tumor-infiltrating lymphocytes (TILs) and the expression of MIF in tumor cells and in TILs were not associated with clinical parameters of ESCC patients. High MIF expression in tumor cells or in TILs or high CXCR4 expression in tumor cells was significantly related to poor survival of ESCC patients (P < 0.05). Multivariate analysis showed that the expression of MIF or CXCR4 in tumor cells and the expression of MIF in TILs were adverse independent factors for disease-free survival (DFS) and overall survival (OS) in the whole cohort of patients (P < 0.05). Furthermore, the expression of MIF and CXCR4 in tumor cells were independent factors for reduced DFS and OS in metastatic/recurrent ESCC patients (P < 0.05). Interestingly, the expressions of MIF and CXCR4 in tumor cells and in TILs were significantly positively correlated (P < 0.05), and the combined MIF and CXCR4 expression in tumor cells was an independent adverse predictive factor for DFS and OS (P < 0.05).

Conclusion

The expressions of MIF and CXCR4 proteins in tumor cells and TILs have different clinically predictive values in ESCC.
Hutchinson-Gilford progeria syndrome accompanied by severe skeletal abnormalities in two Chinese siblings: two case reports
Authors: Xiong Zhimin , Lu Yanmei , Xue Jinjie , Luo Sanchuan , Xu Xiaojuan , Zhang Lusi , Peng Hao , Li Wei , Chen Dengming , Hu Zhengmao , Xia Kun
Published: March 2013

Introduction

Hutchinson-Gilford progeria syndrome is a rare pediatric genetic syndrome with an incidence of one per eight million live births. The disorder is characterized by premature aging, generally leading to death due to myocardial infarction or stroke at approximately 13.4 years of age. The genetic diagnosis and special clinical manifestation in two Han Chinese siblings observed at our clinic for genetic counseling are described in this report. We screened the LMNA gene in these two siblings as well as in their unaffected parents. A homozygous mutation R527C was identified in the affected siblings, and both parents were heterozygous for this variant.

Case presentation

In case 1, the elder 10-year-old female sibling showed the classic physical and radiological changes of Hutchinson-Gilford progeria syndrome in addition to a considerable overlap with the phenotype of mandibuloacral dysplasia.

In case 2, the younger male sibling had begun to show some early physical changes at age six months.

Conclusion

The phenotypic findings in the patients we describe here widen the clinical spectrum of Hutchinson-Gilford progeria syndrome symptoms, providing further recognition of the phenotypic range of LMNA-associated diseases.
Equilibrium and kinetic studies of cadmium(II) and lead(II) ions biosorption onto Ficus carcia leaves
Authors: Farhan Ahlam M , Al-Dujaili Ammar H , Awwad Akl M
Published: March 2013

Background

Ficus carcia leaves (fig leaves) for the removal of cadmium(II) and lead(II) ions from aqueous solutions have been investigated.

Results

The biosorption of cadmium(II) and lead(II) ions was found to be dependent on the solution pH, initial metal ion concentrations, biosorbent dose, contact time, and temperature. The experimental equilibrium biosorption data were analyzed by two widely used two parameters, Langmuir and Freundlich isotherm models.

Conclusions

Langmuir isotherm model provided a better fit with the experimental data than Freundlich model by high correlation coefficients R
2. Kinetic studies showed that pseudo-second-order described the biosorption experimental data better than the pseudo-first-order kinetic model.
Oestrogen increases the activity of oestrogen receptor negative breast cancer stem cells through paracrine EGFR and Notch signalling
Authors: Harrison Hannah , Simões Bruno M , Rogerson Lynsey , Howell Sacha J , Landberg Göran , Clarke Robert B
Published: March 2013

Introduction

Although oestrogen is essential for the development of the normal breast, adult mammary stem cells are known to be oestrogen receptor alpha (ER) negative and rely on paracrine signals in the mammary epithelium for mediation of developmental cues. However, little is known about how systemic oestrogen regulates breast cancer stem cell (CSC) activity.

Methods

Here, we tested the effects of oestrogen on CSC activity in vitro and in vivo and investigated which paracrine signalling pathways locally mediate oestrogen effects.

Results

CSC-enriched populations (ESA+CD44+CD24low) sorted from ER positive patient derived and established cell lines have low or absent ER expression. However, oestrogen stimulated CSC activity demonstrated by increased mammosphere and holoclone formation in vitro and tumour formation in vivo. This effect was abrogated by the anti-oestrogen tamoxifen or ER siRNA. These data suggest that the oestrogen response is mediated through paracrine signalling from non-CSCs to CSCs. We have, therefore, investigated both epidermal growth factor (EGF) and Notch receptor signals downstream of oestrogen. We demonstrate that gefitinib (epidermal growth factor receptor (EGFR) inhibitor) and gamma secretase inhibitors (Notch inhibitor) block oestrogen-induced CSC activity in vitro and in vivo but GSIs more efficiently reduce CSC frequency.

Conclusions

These data establish that EGF and Notch receptor signalling pathways operate downstream of oestrogen in the regulation of ER negative CSCs.
Gender differences in mental health expectancies in early- and midlife in six European countries
Authors: Brugha Traolach S. , Matthews Ruth , Alonso Jordi , Vilagut Gemma , Fouweather Tony , Bruffaerts Ronny , de Girolamo Giovanni , de Graaf Ron , Haro Josep M. , Kovess Viviane , Jagger Carol
Published: March 2013

Background

Health expectancies, taking into account both quality and quantity of life, have generally been based on disability and physical functioning.

Aims

To compare mental health expectancies at age 25 and 55 based on common mental disorders both across countries and between males and females.

Method

Mental health expectancies were calculated by combining mortality data from population life tables and the age-specific prevalence of selected common mental disorders obtained from the European Study of the Epidemiology of Mental Disorders (ESEMeD).

Results

For the male population aged 25 (all countries combined) life expectancy was 52 years and life expectancy spent with a common mental disorder was 1.8 years (95% CI 0.7-2.9),3.4% of overall life expectancy. In comparison, for the female population life expectancy at age 25 was higher (57.9 years) as was life expectancy spent with a common mental disorder (5.1 years, 95% CI 3.6-6.6) and as a proportion of overall life expectancy, 8.8%. By age 55 life expectancy spent with a common mental disorder had reduced to 0.7 years (males) and 2.3 years (females).

Conclusions

Age and gender differences underpin our understanding of years spent with common mental disorders in adulthood. Greater age does not mean living relatively more years with common mental disorder. However, the female population spends more years with common mental disorders and a greater proportion of their longer life expectancy with them (and with each studied separate mental disorder).
MAPK Phosphatase-2 (MKP-2) Is Induced by hCG and Plays a Role in the Regulation of CYP11A1 Expression in MA-10 Leydig Cells
Authors: Gómez Natalia V. , Gorostizaga Alejandra B. , Mori Sequeiros García María M. , Brion Laura , Acquier Andrea , González-Calvar Silvia I. , Méndez Carlos F. , Podestá Ernesto J. , Paz Cristina
Published: March 2013

MAPKs such as ERK1/2 are dephosphorylated, and consequently inactivated, by dual specificity phosphatases (MKPs). In Leydig cells, LH triggers ERK1/2 phosphorylation through the action of protein kinase A. We demonstrate that, in MA-10 Leydig cells, LH receptor activation by human chorionic gonadotropin (hCG) up-regulates MKP-2, a phosphatase that dephosphorylates ERK1/2, among other MAPKs. After 2 hours, hCG and 8-bromo-cAMP (8Br-cAMP) significantly increased MKP-2 mRNA levels (3-fold), which declined to basal levels after 6 hours. MKP-2 protein accumulation exhibited a similar kinetic profile. In cells transiently expressing flag-MKP-2 protein, hCG/8Br-cAMP stimulation promoted the accumulation of the chimera (2.5-fold after 3 h of stimulation). Pharmacologic and biochemical approaches showed that the accumulation of flag-MKP-2 involves a posttranslational modification that increases MKP-2 half-life. MKP-2 down-regulation by a short hairpin RNA (MKP-2 shRNA) raised the levels of phosphorylated ERK1/2 reached by 8Br-cAMP stimulation. This effect was evident after 180 min of stimulation, which suggests that MKP-2 down-regulates the late phase of cAMP-induced ERK1/2 activity. Also, MKP-2 down-regulation by MKP-2 shRNA increased the stimulatory effect of 8Br-cAMP on both promoter activity and messenger levels of CYP11A1, which encodes for the steroidogenic enzyme P450scc and is induced by LH/hCG through protein kinase A and ERK1/2 activities. Our findings demonstrate, for the first time, that LH/hCG tightly regulates MKP-2 expression, which modulates the induction of CYP11A1 by 8Br-cAMP. MKP-2 up-regulation might control ERK1/2 activity in a specific temporal frame to modulate the expression of a finite repertory of ERK-dependent genes.
Part 1: Why I Am Not a Postsecularist
Authors: Mufti Aamir R.
Published: March 2013

This essay argues that the “postsecular” tendency in contemporary humanities and social sciences relies disproportionately on contemporary political Islam to make its case for a “return of religion.” Furthermore, postsecularism generates a highly misleading view of political Islam as an unmediated and unproblematic return to the tradition of (Sunni) Islam, making it difficult to see that political Islam is in fact a result of the great transformation of Muslim societies under colonial rule.
Why Do Robots Rebel? The Labor History of a Cultural Icon
Authors: Higbie Tobias
Published: March 2013

In his sustained treatment of the Czech author Karel Čapek's masterwork, R.U.R., Toby Higbie suggests the ways that the playwright's imagery (repeated in subsequent science fiction) of “robots” drew on contemporary fears and foreboding about industrial work. For one, the image of machine-made men bore a close resemblance to the bureaucratic transformation of factory floors under the regime of Taylorism. However, Higbie asks, “Could democracy survive with robot-like citizens? What kind of politics would come from people so dominated by the machine process?” After tracking the robot image from the 1920s through the dystopias of the Great Depression, Higbie discusses the similarities and discontinuities of imaginative robotic forms within the cyber-fiction of the twenty-first century.
The permeability of red blood cells to chloride, urea, and water
Authors: Brahm Jesper
Published: March 2013

Red blood cell (RBC) permeability (P, cm s-1) of human, dog, chick, duck, and Amphiuma means to 36Cl-, 14C-urea, and 3H2O was determined under self-exchange conditions (25°C, pH 7.2-7.5). PCl of all RBC species is 0.9-2.7 × 10-4 at CCl 127-150 mM. Purea is 0.83 × 10-6 in chick and 1.65 × 10-6 in duck RBC at Curea 1-500 mM. In human, dog, and Amphiuma RBC Purea is concentration-dependent at 1-1000 mM (Michaelis-Menten-like kinetics; K½ respectively 345, 173, 107 mM). At 1 mM urea Purea is 2.60 × 10-4 (human), 4.67 × 10-4 (dog), and 0.30 × 10-4 (Amphiuma). Diffusional water permeability Pd is 0.39 × 10-3 (Amphiuma), 0.84 × 10-3 (chick), 2.35 × 10-3 (human), 3.13 × 10-3 (dog), and 5.95 × 10-3 (duck). DIDS, DNDS, and phloretin inhibited PCl >99%. PCMBS, PCMB, and phloretin inhibited Purea >99% in human, dog, and Amphiuma RBC. Inhibition was absent in chick and duck RBC. PCMB and PCMBS inhibited Pd in human, dog, and duck, but not chick and Amphiuma RBC. Temperature dependence, EA, kJ mol-1, of PCl is 75 (Amphiuma), 100 (dog), and 118 (duck). EA of Purea is 70 (duck), and 53 (Amphiuma). EA of Pd is 35 (duck), and 32 (Amphiuma). Combining this study of PCl, Pd, Purea, and inhibition of Psolute with our previous RBC studies indicates that anion, urea, and water transporters respectively transport only chloride (all species), only urea (human, dog, Amphiuma), and only water (human, dog, duck). Water do not share the urea transporter with urea, and the solute transport is not coupled under normal physiological conditions.
Finding the best estimates of metabolic rates in a coral reef fish
Authors: Roche Dominique G. , Binning Sandra A. , Bosiger Yoland , Johansen Jacob L. , Rummer Jodie L.
Published: March 2013

Metabolic rates of aquatic organisms are estimated from measurements of oxygen consumption rates (ṀO2) through swimming and resting respirometry. These distinct approaches are increasingly used in eco- and conservation physiology studies; however, few studies have tested whether they yield comparable results. We examined whether two fundamental ṀO2 measures, standard metabolic rate (SMR) and maximum metabolic rate (MMR), vary based on the method employed. Ten bridled monocle bream (Scolopsis bilineatus) were exercised using (1) a critical swimming speed (Ucrit) protocol, (2) a 15 min exhaustive chase protocol and (3) a 3 min exhaustive chase protocol followed by brief air exposure. Protocol (1) was performed in a swimming respirometer whereas protocols (2) and (3) were followed by resting respirometry. SMR estimates in swimming respirometry were similar to those in resting respirometry when a three-parameter exponential or power function was used to extrapolate the swimming speed-ṀO2 relationship to zero swimming speed. In contrast, MMR using the Ucrit protocol was 36% higher than MMR derived from the 15 min chase protocol and 23% higher than MMR using the 3 min chase 1 min air exposure protocol. For strong steady (endurance) swimmers, such as S. bilineatus, swimming respirometry can produce more accurate MMR estimates than exhaustive chase protocols because oxygen consumption is measured during exertion. However, when swimming respirometry is impractical, exhaustive chase protocols should be supplemented with brief air exposure to improve measurement accuracy. Caution is warranted when comparing MMR estimates obtained with different respirometry methods unless they are cross-validated on a species-specific basis.
Sodalite Layer as a Protective Barrier for Diesel Particulate Filters
Authors: Dinh Thanh-Nghia , Kimura Riichiro , Kamimura Yoshihiro , Ogura Masaru , Okubo Tatsuya
Published: March 2013

We report the preparation of a sodalite (SOD) layer on a cordierite substrate as a protective barrier against the potassium species using an in situ hydrothermal method. The performance of the potassium carbonate-loaded layer was characterized by scanning electron microscopy–energy-dispersive X-ray (SEM-EDX) measurements before and after thermal treatment at 1073 K for 5 and 50 h. A low potassium content detected at the layer–substrate interface of the samples before and after heating for 5 h indicates that the cordierite substrate was protected against potassium species by the generated SOD layer, whereas heating for the longer period of 50 h resulted in further migration of potassium species. The mobility of the potassium species is likely to be principally governed by diffusion along the defects of the material that appear during thermal treatment. It is suggested that migration of the potassium species might be prevented by the formation of a defect-free layer.
Drosophila immune priming against Pseudomonas aeruginosa is short-lasting and depends on cellular and humoral immunity
Authors: Christofi Theodoulakis , Apidianakis Yiorgos
Published: March 2013

Immune responses are traditionally divided into the innate and the adaptive arm, both of which are present in vertebrates, while only the innate arm is found in invertebrates. Immune priming experiments in Drosophila melanogaster and other invertebrates during the last decade have challenged this dogma, questioning the boundaries between innate and adaptive immunity. Studies on repeated inoculation of Drosophila with microbes reveal a long-lasting cellular immunity adaptation against particular microorganisms. Here we study the lasting effect of immune priming against infection with Pseudomonas aeruginosa, an opportunistic human pathogen that is lethal to the common fruit fly. Drosophila priming with heat-killed or low in virulence P. aeruginosa extends fly survival during a secondary lethal infection with a virulent strain of the same species. The protective immune response can last for more than 10 days after exposure to a persistent low-in-virulence live infection, but it is eliminated 7 days after the host is primed with heat-killed bacteria. Moreover, not only the cellular, but also the systemic NF-κB-mediated immune responses contribute to immune priming. Thus each microbe might elicit different mechanisms of immune priming that may or may not last for long.
Anacardic acid, a histone acetyltransferase inhibitor, modulates LPS-induced IL-8 expression in a human alveolar epithelial cell line A549
Authors: Yasutake Tetsuo , Wada Hiroo , Higaki Manabu , Nakamura Masuo , Honda Kojiro , Watanabe Masato , Ishii Haruyuki , Kamiya Shigeru , Takizawa Hajime , Goto Hajime
Published: March 2013

Objective and design:The histone acetylation processes, which are believed to play a critical role in the regulation of many inflammatory genes, are reversible and regulated by histone acetyltransferases (HATs), which promote acetylation, and histone deacetylases (HDACs), which promote deacetylation. We studied the effects of lipopolysaccharide (LPS) on histone acetylation and its role in the regulation of interleukin (IL)-8 expression. 

Material:A human alveolar epithelial cell line A549 was usedinvitro.

Methods:Histone H4 acetylation at the IL-8 promoter region was assessed by a chromatin immunoprecipitation (ChIP) assay. The expression and production of IL-8 were evaluated by quantitative polymerase chain reaction and specific immunoassay. Effects of a HDAC inhibitor, trichostatin A (TSA), and a HAT inhibitor, anacardic acid, were assessed. 

Results:Escherichia coli-derived LPS showed a dose- and time-dependent stimulatory effect on IL-8 protein production and mRNA expression in A549 cellsin vitro. LPS showed a significant stimulatory effect on histone H4 acetylation at the IL-8 promoter region by ChIP assay. Pretreatment with TSA showed a dose-dependent stimulatory effect on IL-8 release from A549 cells as compared to LPS alone. Conversely, pretreatment with anacardic acid inhibited IL-8 production and expression in A549 cells. 

Conclusion:These data suggest that LPS-mediated proinflammatory responses in the lungs might be modulated via changing chromatin remodeling by HAT inhibition.
Optimal isoperimetric inequalities for complete proper minimal submanifolds in hyperbolic space
Authors: Min Sung-Hong , Seo Keomkyo
Published: March 2013

Let Σ be a k-dimensional complete proper minimal submanifold in the Poincaré ball model Bn
of hyperbolic geometry. If we consider Σ as a subset of the unit ball Bn
in Euclidean space, we can measure the Euclidean volumes of the given minimal submanifold Σ and the ideal boundary

∂
∞

Σ

$\partial _\infty \Sigma $

, say

Vol
ℝ

(
Σ
)

$\operatorname{Vol}_{\mathbb {R}}(\Sigma )$

and

Vol
ℝ

(

∂
∞

Σ
)

$\operatorname{Vol}_{\mathbb {R}}(\partial _\infty \Sigma )$

, respectively. Using this concept, we prove an optimal linear isoperimetric inequality. We also prove that if

Vol
ℝ

(

∂
∞

Σ
)

≥

Vol
ℝ

(

𝕊

k
-
1

)

$\operatorname{Vol}_{\mathbb {R}}(\partial _\infty \Sigma ) \ge \operatorname{Vol}_{\mathbb {R}}(\mathbb {S}^{k-1})$

, then Σ satisfies the classical isoperimetric inequality. By proving the monotonicity theorem for such Σ, we further obtain a sharp lower bound for the Euclidean volume

Vol
ℝ

(
Σ
)

$\operatorname{Vol}_{\mathbb {R}}(\Sigma )$

, which is an extension of Fraser–Schoen and Brendle's recent results to hyperbolic space.
Moreover we introduce the Möbius volume of Σ in Bn
to prove an isoperimetric inequality via the Möbius volume for Σ.
Simplicial geometry of unital lattice-ordered abelian groups
Authors: Cabrer Leonardo Manuel
Published: March 2013

By a unital
ℓ-group we mean a lattice-ordered abelian group with a distinguished order unit. This paper is concerned with the category

𝖴

f
p

$\mathsf {U}_{\textup {fp}}$

of finitely presented unital ℓ-groups. Using the duality between

𝖴

f
p

$\mathsf {U}_{\textup {fp}}$

and a category of rational polyhedra, we will provide (i) a construction of finite limits and co-limits in

𝖴

f
p

$\mathsf {U}_{\textup {fp}}$

; (ii) a Cantor–Bernstein–Schröder theorem for finitely presented unital ℓ-groups;
(iii) a proof that the fibered product of finitely generated projective unital ℓ-groups is projective;
(iv) a geometrical characterization of exact unital ℓ-groups.
Identification of Acoustic Emissions From Porosity and Waviness Defects in Continuous Fiber Reinforced Composites
Authors: Qamhia Issam I. , Lauer-Hunt Eric M. , El-Hajjar Rani F.
Published: March 2013

The manufacturing of composite structures can result in manufacturing defects such as fiber waviness and porosity. These can have a significant and usually adverse impact on the mechanical and non-mechanical properties. In this study, we propose the use of an acoustic emission methodology to study the acoustic signature when porosity and fiber waviness are present in a composite structure. The methodology shows the possibility of identifying the signals near regions of high stress concentration in specimens subject to quasi-static loading. The analysis of the acoustic waveforms is performed through temporal characterization of the acoustic emissions and individual waveform analysis. The study reveals that the presence of fiber waviness and local porosity can be detected by the time at which major events start to occur and from the recorded magnitudes of cumulative energy and counts against time. However, the combined presence of porosity and waviness results in increased difficulties in the interpretation of the acoustic emission signals. A fast Fourier transform analysis of the captured waveform is examined in order to decouple the acoustic emissions and understand the defect modes present.
Catastrophic Failure in Cavitation Erosion Testing
Authors: Meged Y.
Published: March 2013

Catastrophic failure of metallic test specimens under cavitation erosion conditions is evidenced by an increasing rate of material loss. The typical cumulative erosion–time curve for this type of failure is denoted as type C. This type of failure depends on the characteristics of the test material, the test method, and the severity of the test conditions. A review of 264 cavitation erosion–time curves, produced via seven test methods, reveals that type C curves are found with 18 % of the specimens and 58 % of the tests performed via the rotating disc test method. This study shows that type C erosion–time curves can be modeled, analyzed, and extrapolated by means of the transient response erosion model. The two main conclusions from this study are that (i) ductile metallic materials are vulnerable to catastrophic erosion failure under severe cavitation erosion conditions, and (ii) the most effective erosion test method for the detection and classification of these materials and conditions is the rotating disc method.
Potentials of copper slag utilisation in the manufacture of ordinary Portland cement
Authors: Ali Mohammad M. , Agarwal Satish K. , Pahuja Ashwani
Published: March 2013

The addition of copper oxide in cement raw mix is known to improve its burnability, with increase in formation of the alite phase. Copper slag, a by-product of the metallurgical industry, containing copper oxide can therefore be a useful additive in the manufacture of cement, particularly for hard burning raw mixes. This paper presents a study on the effect of addition of 1·5–2·5% of a typical by-product copper slag sample to cement raw mixes prepared from two different limestone samples, with free silica content of 5·52 and 10·97% and average grain sizes of 124 and 175 μm. The clinker parameters such as limestone saturation factor, silica modulus and alumina modulus were in the ranges 0·91–0·92, 2·11–2·29 and 1·0–1·20, respectively. The fineness values of the raw mixes were 3·50–4·20 and 20·80–21·34% retained on 212 and 90 μm sieves, respectively. Burnability studies of these raw mixes were conducted at temperatures of 1300, 1350, 1400 and 1450°C, with retention time of 20 min, and showed increase in the rate of lime assimilation, acceleration in the formation and growth of C3S and lowering in clinkerisation temperature by 50°C. The free silica was found to be completely assimilated at 1400°C in mixes containing copper slag. The mineral phase developments and microstructures of laboratory clinker samples fired at 1400 ± 5°C were comparable to control clinker prepared at 1450 ± 5°C. Physical properties of ordinary Portland cement prepared using this clinker showed performance comparable with control cement. The copper slag contains heavy elements, therefore a leaching study was also conducted by immersing hardened cement pastes in distilled water for 6 months. The leachates, such as barium, copper and chromium, were found to be 0·032, 0·005 and 0·031 ppm, indicating fixation of these elements in the clinker mineral phases.
Stress–force–fabric relationship for planar granular materials
Authors: SEYEDI HOSSEININIA E.
Published: March 2013

This paper presents the theoretical development of a relationship between the average stress components and the micromechanical fabric anisotropy characteristics within assemblies of planar particles. The main feature of the modified formulation is the ability to consider both inherent and induced anisotropy conditions within the assembly. This was achieved by amending the definition of the contact vector between particles in the stress–force–fabric relationship. By using numerical discrete-element method (DEM), a series of inherently anisotropic granular materials were simulated in order to verify the accuracy of the proposed formulation. In the simulations, the geometry of the particles was chosen to be irregular polygons. The shear capacity of the assemblies during the loading process was calculated from direct measurement of macroscopic stress components, and from anisotropy fabric parameters. By comparing the results, it is shown that reasonable agreement exists between the calculated and measured values.
Phenotypic Diversity of Root Anatomical and Architectural Traits in Zea Species
Authors: Burton Amy L. , Brown Kathleen M. , Lynch Jonathan P.
Published: March 2013

We characterized phenotypic variation for root traits in 256 Zea spp. accessions, including maize landraces and Z. mays L. subsp. huehuetenangensis (H. H. Iltis & Doebley) Doebley, subsp. mexicana (Schrad.) H. H. Iltis, and subsp. parviglumis H. H. Iltis & Doebley, Z. nicaraguensis H. H. Iltis & B. F. Benz, Z. perennis (Hitchc.) Reeves & Mangelsd., and Z. luxurians (Durieu & Asch.) R. M. Bird. Anatomical traits included areas of the cross‐section, stele, cortex, aerenchyma, and xylem and number of cortical cells and cell files. Architectural traits included diameters of the nodal root system, individual crown roots, and the stem; numbers of seminal and nodal roots; biomass; and nodal root length and branching. Ranges for anatomical traits were similar for teosintes and landraces, except for aerenchyma and xylem areas, and number of cortical cells. Landraces had greater variation for architectural traits except for nodal root number and branching, and had larger mean stele and xylem areas, longer nodal roots, wider nodal systems, and more seminal roots than teosintes. In contrast, teosintes were smaller but had more nodal roots with greater branching. At a common plant size, teosintes would have lower mean values for all anatomical traits, except for number of cortical cells and cell files. Teosintes had greater scaled values for all architectural traits except average root diameter. Cluster analysis divided accessions into eight root phenotypes. Phenotypic diversity for root traits in the genus Zea could be a valuable resource for improving stress tolerance in maize.
Leaf Dhurrin Content is a Quantitative Measure of the Level of Pre‐ and Postflowering Drought Tolerance in Sorghum
Authors: Burke John J. , Chen Junping , Burow Gloria , Mechref Yehia , Rosenow Darrell , Payton Paxton , Xin Zhanguo , Hayes Chad M.
Published: March 2013

The presence of preflowering or postflowering drought tolerance has been described in sorghum [Sorghum bicolor (L.) Moench]. Sorghum lines with preflowering drought tolerance tend to senesce under postflowering drought stress while sorghum lines with postflowering drought tolerance (the stay‐green trait) tend to be sensitive to preflowering drought stress. Assessments of these phenotypes have been dependent on the incidence of drought stress conditions at specific developmental stages to achieve meaningful evaluation. Therefore, field‐based evaluations, most of which are visual, are notoriously difficult to perform and require growing lines in multiple locations across several years to achieve efficient selection for these traits. Here we report and demonstrate a correlation between leaf dhurrin [(S)‐p‐hydroxymandelonitrile‐β‐D‐glucopyranoside] contents and the level of stay‐green based on leaf and plant death ratings during postflowering drought stresses. Postflowering drought‐tolerant stay‐green sorghums had elevated dhurrin contents while preflowering drought‐tolerant sorghum lines exhibited lower dhurrin contents. Lines with intermediate leaf and plant death ratings exhibited intermediate dhurrin levels. Finally, dhurrin levels determined before flowering from sorghum grown under irrigated or dryland conditions were related to the degree of pre‐ or postflowering drought tolerance.
Noninvasive Monitoring of Soil Water Dynamics in Mixed Cropping Systems: A Case Study in Ratchaburi Province, Thailand
Authors: Garré S. , Coteur I. , Wongleecharoen C. , Kongkaew T. , Diels J. , Vanderborght J.
Published: March 2013

Agriculture on shallow or steep soils in the humid tropics often leads to low resource use efficiency. Contour hedgerow intercropping systems have been proposed to reduce run‐off and control soil erosion. However, competition for water and nutrients between crops and associated hedgerows may reduce the overall performance of contour hedgerow systems. Electrical resistivity tomography (ERT) is a valuable technique used to assess the distribution and dynamics of soil moisture noninvasively. In this study, we demonstrated its potential to measure soil water depletion in the field in distinct cropping patterns in Ratchaburi province, Thailand. The measurements showed that the soils of our experimental plots were very heterogeneous both along the slope as with depth. This observation highlighted some constraints of the ERT method for soil moisture monitoring in the field, such as the difficulty of defining a relationship between electrical conductivity and soil moisture in very heterogeneous soils. Nevertheless, spatial analysis of the data revealed contrasting water depletion patterns under monocropping and intercropping systems. In this way, ERT provides access to information about the vadose zone moisture dynamics that would be unavailable with classical soil moisture measurements.
Simple three-level neutral point voltage balance control strategy based on SVPWM
Authors: Gong Bo , Cheng Shanmei , Qin Yi
Published: March 2013

The unbalance of the neutral point voltage is an inherent problem of three-level neutral-point-clamped (NPC) inverter, the effect of neutral point voltage balancing which is caused by voltage vector is analyzed, and the relationship of the voltage offset and neutral point voltage is studied in this paper. This paper proposes a novel neutral point balance strategy for three-level NPC inverter based on space vector pulse width modulation (SVPWM). A voltage offset is added to the modulation wave, and a closed-loop neutral point voltage balance control system is designed. In the control system, the dwelling time of synthesis voltage vectors for SVPWM is varied to solve the problem of the unbalance of the neutral point voltage, the sequence of the voltage vectors maintains unchanging. Simulation and experimental results show the neutral point voltage balancing control strategy based on SVPWM is effective.
Shunt power electronic buffer as active filter and energy flow controller
Authors: Szromba Andrzej
Published: March 2013

The considered shunt active power filter can be controlled not only to compensate non-active current in the supply source, but additionally to optimize energy flow between the source and the load. In such a case the filter shapes the source current to be active and simultaneously regulates its magnitude. The presented filter/buffer can operate properly even when the load contains AC or DC variable energy source of any characteristic. The device can optimize energy flow for a single load, but also for a group of loads as well. The distinctive feature of the employed control method of the filter/buffer is that certain changes of energy stored in the device are utilized as the source of information concerning the active current of the load. This control method is very flexible and can be implemented to nearly all structures of active filters, for DC, single- and multiphase circuits.
Computationally efficient method of simulation of an electric drive impact on the power grid
Authors: Beniak Ryszard , Gardecki Arkadiusz
Published: March 2013

This paper presents a computationally efficient method for modelling an impact of the converter drive on the power grid. The formalized variable structure method (FVSM) allows for comprehensive studies of the effect on the power grid and examining the relation between this effect and the number of drive and feeding line parameters. In order to obtain a comprehensive model along with the model of the power grid, the parameters that are applied originate from a drive of a coal-fired power station. These parameters have been determined based on assessment and estimation. The estimation process was conducted with the aid of a model that allows for the commutation of power electronic elements. The authors confirmed that the model was correct by comparing empirical and theoretical voltage and current waveforms. Harmonic content of the voltage and current in the power grid which feeds the drive are considered to be the measure of the converter drive impact on the power grid. The standard method for the reduction of a harmonic content in the voltage and current involves the application of line reactors and distribution or converter transformers. As an example, the authors determine the impact of the drive on the power grid with respect to the adopted parameters of the line reactor. This example presents FVSM abilities with regard to simulation of complex systems that contain power grid components and converter drives.
Optimal location of interline power flow controller in a power system network using ABC algorithm
Authors: Sreejith S. , Psimon Sishaj , Selvan M.P.
Published: March 2013

This paper proposes a methodology based on installation cost for locating the optimal position of interline power flow controller (IPFC) in a power system network. Here both conventional and non conventional optimization tools such as LR and ABC are applied. This methodology is formulated mathematically based on installation cost of the FACTS device and active power generation cost. The capability of IPFC to control the real and reactive power simultaneously in multiple transmission lines is exploited here. Apart from locating the optimal position of IPFC, this algorithm is used to find the optimal dispatch of the generating units and the optimal value of IPFC parameters. IPFC is modeled using Power Injection (PI) model and incorporated into the problem formulation. This proposed method is compared with that of conventional LR method by validating on standard test systems like 5-bus, IEEE 30-bus and IEEE 118-bus systems. A detailed discussion on power flow and voltage profile improvement is carried out which reveals that incorporating IPFC into power system network in its optimal location significantly enhance the load margin as well as the reliability of the system.
Analysis of the electromagnetic response of complex dispersive material with the single-step wideband finite element method
Authors: Butryło Bogusław
Published: March 2013

The paper describes the formulation and implementation of the broadband finite element time domain algorithm. The presented formalism is valid to analysis of electromagnetic phenomena in linear, frequency selective materials. The complex profile of permittivity of materials is approximated using a set of the Lorentz resonance models. The solution of the integro-differential second order equation is obtained using a singlestep integration scheme and a recursive convolution algorithm. The discussed formulation enables to adopt the structure of the narrowband part as well as the phase of calculation of the convolution equations for the subsequent components. The properties of the algorithm are validated using a finite difference broadband algorithm.
A new method for evaluation of transformer drying process using transfer function analysis and artificial neural network
Authors: Firoozi Hormatollah , Bigdeli Mehdi
Published: March 2013

Since a few years ago, there is an increasing interest for utilization of transfer functions (TF) as a reliable method for diagnosing of mechanical faults in transformer structure. However, this paper aims to develop the application of TF method in order to evaluate the drying quality of active part during the manufacturing process of transformer. To reach this goal, the required measurements are carried out on 50 MVA 132 KV/33 KV power transformer when active part is placed in the drying chamber. Two different features extracted from the measured TFs are then used as the inputs to artificial neural network (ANN) to give an estimate for required time in drying process. Results show that this new represented method could well forecast the required time. The results obtained from this method are valid for all the transformers which have the same design.
Nonlinear boundary condition in electromagnetic theory – analytical scheme of formulation
Authors: Sowa Marcin , Spałek Dariusz
Published: March 2013

The paper presents a method of how the nonlinear boundary condition [1] may be applied in nonlinear problems of electromagnetic field theory. It is introduced for problems with nonlinear conductivity. An analytical procedure has been constructed, which seeks to reduce calculations related with the nonlinear region. In order to verify the proposed solutions, two problems have been formulated: one of linear and the other of cylindrical symmetry. These have been additionally solved by the authors’ modification of the perturbation method that has been described in previous papers [7, 8, 10]. The electromagnetic field distribution obtained thereby has served as a referential result since it can obtain very accurate solutions [10]. Relative errors of electric and magnetic field strength are introduced to verify the results.
Analysis of Tourism Service Quality in Kołobrzeg Region by Means of Time Series Models
Authors: Dłubakowska-Puzio Ewa K. , Karpuk Michał , Puzio Kamil
Published: March 2013

The aim of the given paper is to present the analysis of tourism services by means of time series models and forecasting of evaluation of tourism services. Tourism services are analysed according to various parameters: hotel stay price, hotel services quality (such as cleanness of rooms, check-in, information provision etc.), catering quality and medical service quality. The research has been undertaken on the basis of responses of foreign guests of 13 hotels in Kołobrzeg region taken from 1400 questionnaires divided according to age and sex of respondents. Various econometric models were used for the analysis of statistic regularities. First, customers evaluated quality of their stay in hotels. These data were examined during the 2006-2009 time period as a stochastic process. It was found that the processes are nonstationary, that is why the ARIMA (1,1,1) model was used in the study. On the basis of the analyses and prognoses one can deduce that models of time series make it possible to estimate a tendency that occurs for an analysed parameter, however misprediction is quite possible to appear (up to 30 %). Similar results were achieved during the analysis of evaluation of hotel stay quality on the basis of sex of respondents. One should point out that an average value of male evaluation rate is higher than an average value of female evaluation rate. Time series for analysed variables were integrated into level I(1). A certain co-integrational connection was found between the evaluation of hotel stay and number of stays in a given hotel, where tourists that have already visited a given hotel for several times presumably give a high evaluation rate of hotel stay quality. The result of the analysis of long-term relation between hotel stay and duration of check-in is presented in high mutual dependence of hotel evaluation rate on evaluation of check-in duration. A hotel stay price influences hotel stay evaluation in a negative way, but catering and medical services are considered as standard and do not have any particular influence on hotel stay evaluation. The undertaken study shows that methods that take into account time series can be successfully used in analysis of parameters of tourist comfort and in evaluation of hotel services.
Selected Challenges from Spatial Statistics for Spatial Econometricians
Authors: Griffith Daniel A.
Published: March 2013

Griffith and Paelinck (2011) present selected non-standard spatial statistics and spatial econometrics topics that address issues associated with spatial econometric methodology. This paper addresses the following challenges posed by spatial autocorrelation alluded to and/or derived from the spatial statistics topics of this book: the Gaussian random variable Jacobian term for massive datasets; topological features of georeferenced data; eigenvector spatial filtering-based georeferenced data generating mechanisms; and, interpreting random effects.
Spatial Analysis of the Labour Market by Using Econometric Tools. The Case of Lower Silesia Region (Dolnośląskie voivodship)
Authors: Litwińska Elżbieta
Published: March 2013

This paper presents the application of econometric techniques to examine the labour market in Lower Silesia. First the analysis was performed on a data set for variables connected with labour market recorded in poviats (NUTS 4). In order to determine the existence of spatial autocorrelation Moran’s statistics I was calculated. Then the spatial regression model was used to describe the relationship between the rate of unemployment and other variables. Next, LISA cluster maps were generated for units at NUTS 5 level. The results indicate the spatial dimension of the unemployment and its tendency to creating concentrations.
Dynamics of Change in Spatial Dependencies in Blood Donation System in Poland
Authors: Ojrzyńska Anna , Twaróg Sebastian
Published: March 2013

Blood donation allows to obtain blood and its components from healthy people in a bid to help treatment of anonymous individuals, relying on timely and sufficient supplies of matching blood. Being a social initiative, it depends on multiple factors. Those factors are possible to be shaped and are subject to research. This paper aims to present the dynamics of change in spatial dependencies determining development of blood donation in Poland from 2005 to 2010. Spatial analysis of data enables identification of similarities and differences between voivodeships in a given period. Testing of hypothesis concerning spatial autocorrelation was carried out using tools of spatial statistics. This paper's subject matter concentrates on pointing towards the direction and extent of changes illustrated with an example of analysis investigating the number of blood donations per hospital bed in wards with high demand on blood and its components. The number of blood donors per 1000 residents in 18 – 65 age was also analysed.
Measuring Cost Efficiency of Ukrainian Banks in 2008
Authors: Pilyavskyy Anatoliy , Matsiv Yuriy , Vovchak Olga
Published: March 2013

The paper presents the results of a stochastic frontier analysis (SFA) of cost-efficiency of Ukrainian banks. As of lack of data on the personnel costs, we had to set limits to the year of 2008 only. To modeling banking activity, we apply the intermediary approach as one of the most commonly used in literature. Considering the results of statistical tests, we chose translog functional form of cost function and half–normal distribution of random inefficiency term. As a result of the research, we found out that efficiency of Ukrainian banks varies within 0.5224 and 0.9869 with an average value of 0.8734. Having checked a range of hypotheses, we discovered insignificant distinctions among banks by their size, type of owner and location.
On Misspecification of Spatial Weight Matrix for Small Area Estimation in Longitudinal Analysis
Authors: Żądło Tomasz
Published: March 2013

The problem of prediction of subpopulation (domain) total is studied as in Rao (2003). Considerations are based on spatially correlated longitudinal data. The domain of interest can be defined after sample selection what implies its random sample size. The special case of the General Linear Mixed Model is proposed where two random components obey assumptions of spatial and temporal moving average process respectively. Moreover, it is assumed that the population may change in time and elements’ affiliations to subpopulation may change in time as well. The proposed model is a generalization of longitudinal models studied by e.g. Verbeke, Molenberghs (2000) and Hedeker, Gibbons (2006). The best linear unbiased predictor (BLUP) is derived. It may be used even if the sample size in the subpopulation of interest in the period of interest is zero. In the Monte Carlo simulation study the accuracy of the empirical version of the BLUP will be studied in the case of correct and incorrect specification of the spatial weight matrix. Two cases of model misspecification are studied. In the first case the misspecified spatial weight is used. In the second case independence of random components is assumed but the variable which is used to compute elements of spatial weight matrix in the correct case will be used as auxiliary variable in the model.