bluuebunny/crossref_metadata_2025 huggingface dataset:
Liquid chromatography‐tandem mass spectrometry (LC‐MS/MS) for analysis of endogenous steroids in the luteal phase and early pregnancy in dogs: a pilot study
Authors: Holst Bodil S. , Kushnir Mark M. , Bergquist Jonas
Published: November 2015

Background

Blood samples from dogs are often limited in volume, only allowing few steroids to be quantified with immunoassays. In addition, immunoassays may be compromised by interferences such as anti‐reagent antibodies. Liquid chromatography‐tandem mass spectrometry (LC‐MS/MS) can be used for the simultaneous quantitation of several steroids. This has not been described in dogs before.

Objectives

The aims were to use LC‐MS/MS to study steroid profiles in early pregnancy and luteal phase in dogs, and to determine if differences exist between pregnant (P) and nonpregnant (NP) dogs.

Methods

Nine female dogs were included, 4 during a NP luteal phase, 4 during a P luteal phase, and one during one NP and one P luteal phase. Blood samples were collected around the time of the LH surge (Day 0) and on Day 26. Serum was analyzed for 5 classes of steroids, including glucocorticoids, androgens, estrogens, pregnanes, and progestins, using LC‐MS/MS methods.

Results

The concentration of progesterone was significantly higher on Day 26 in P than in NP bitches. Distribution of concentrations of glucocorticoids, androgens, estrogens, or pregnanes in P and NP dogs were not statistically different. The predominating glucocorticoid was cortisol, and dihydroepiandrosterone (DHEA) was the predominating androgen. Concentration of estrone was comparable to oestradiol, whereas concentrations of pregnenolone were higher than those of 17‐OH pregnenolone.

Conclusions

Only concentration of progesterone differed between P and NP bitches, being significantly higher on Day 26 in P than in NP bitches. LC‐MS/MS offers interesting possibilities for studies of canine reproductive endocrinology.
IMAGING DIAGNOSIS—VERTEBRAL POLYOSTOTIC LYMPHOMA IN A GERIATRIC DOG
Authors: Kornder Julie , Platt Simon R. , Eagleson Joe , Kent Marc , Holmes Shannon P.
Published: November 2015

A 9‐year‐old spayed female Scottish terrier presented with an 8‐day history of progressive paraparesis. Neurological examination suggested a painful T3‐L3 myelopathy. Multifocal uniform contrast‐enhancing masses involving the vertebral bodies, pedicles, laminae, and spinous processes of two vertebrae and compressing the spinal cord were present on MRI. Fluoroscopic‐guided fine needle aspiration of one of the vertebral lesions revealed a predominantly lymphoblastic population of cells compatible with a diagnosis of lymphoma. To the authors’ knowledge, this represents the first published case of canine lymphoma with vertebral involvement, characterized with MRI.
The zebrafish pinball wizard gene encodes WRB, a tail‐anchored‐protein receptor essential for inner‐ear hair cells and retinal photoreceptors
Authors: Lin Shuh‐Yow , Vollrath Melissa A. , Mangosing Sara , Shen Jun , Cardenas Elena , Corey David P.
Published: November 2015

Key points

The zebrafish pinball wizard (pwi) mutant is deaf and blind.

The pwi phenotype includes a reduced auditory startle response and reduced visual evoked potentials, suggesting fatigue of synaptic release at ribbon synapses in hair cells and photoreceptors.

The gene defective in the pwi mutant is WRB, a protein homologous to the yeast protein Get1, which is involved in the insertion of ‘tail‐anchored’ membrane proteins.

Many tail‐anchored proteins are associated with synaptic vesicles, and both vesicles and synaptic ribbons are reduced in synaptic regions of hair cells in pwi.

Abnormal processing of synaptic vesicle proteins important for ribbon synapses can explain the pwi phenotype.

In a large‐scale zebrafish insertional mutagenesis screen, we identified the pinball wizard (pwi) line, which displays a deafness and blindness phenotype. Although the gross morphology and structure of the pwi larval inner ear was near normal, acoustic startle stimuli evoked smaller postsynaptic responses in afferent neurons, which rapidly fatigued. In the retina, similarly, an abnormal electroretinogram suggested reduced transmission at the photoreceptor ribbon synapse. A functional deficit in these specialized synapses was further supported by a reduction of synaptic marker proteins Rab3 and cysteine‐string protein (CSP/Dnajc5) in hair cells and photoreceptors, as well as by a reduction of the number of both ribbons and vesicles surrounding the ribbons in hair cells. The pwi gene encodes a homologue of the yeast Get1 and human tryptophan‐rich basic (WRB) proteins, which are receptors for membrane insertion of tail‐anchored (TA) proteins. We identified more than 100 TA proteins expressed in hair cells, including many synaptic proteins. The expression of synaptobrevin and syntaxin 3, TA proteins essential for vesicle fusion, was reduced in the synaptic layers of mutant retina, consistent with a role for the pwi/WRB protein in TA‐protein processing. The WRB protein was located near the apical domain and the ribbons in hair cells, and in the inner segment and the axon of the photoreceptor, consistent with a role in vesicle biogenesis or trafficking. Taken together, our results suggest that WRB plays a critical role in synaptic functions in these two sensory cells, and that disrupted processing of synaptic vesicle TA proteins explains much of the mutant phenotype.
Análisis de la característica corriente-voltaje de diodos orgánicos emisores de luz (OLEDs) basados en polímeros depositados por spin coating.
Authors: Méndez-Pinzón Henry Alberto , Pardo-Pardo Diana Rocío , Cuéllar-Alvarado Juan Pablo , Salcedo-Reyes Juan Carlos , Vera Ricardo , Páez-Sierra Beynor Antonio
Published: November 2015

Polymer-based organic light-emitting diodes (OLEDs) with the structure ITO / PEDOT:PSS / MDMO-PPV / Metal were prepared by spin coating. It is known that electroluminescence of these devices is strongly dependent on the material used as cathode and on the deposition parameters of the polymer electroluminescent layer MDMO-PPV. Objective. In this work the effect of i) the frequency of the spin coater (1000-8000 rpm), ii) the concentration of the MDMO-PPV: Toluene solution, and iii) the material used as cathode (Aluminium or Silver) on the electrical response of the devices, was evaluated through current-voltage (I-V) measurements. Materials and methods. PEDOT:PPS and MDMO-PPV organic layers were deposited by spin coating on ITO substrates, and the OLED structure was completed with cathodes of aluminium and silver. The electric response of the devices was evaluated based on the I-V characteristics. Results. Diodes prepared with thinner organic films allow higher currents at lower voltages; this can be achieved either by increasing the frequency of the spin coater or by using concentrations of MDMO-PPV: Toluene lower than 2% weight. A fit of the experimental data showed that the diodes have two contributions to the current. The first one is attributed to parasitic currents between anode and cathode, and the other one is a parallel current through the organic layer, in which the carrier injection mechanism is mediated by thermionic emission. Conclusions. The results fitting and the energy level alignment through the whole structure show that PPV-based OLEDs are unipolar devices, with current mainly attributed to hole transport.

Key words: organic semiconductors, OLEDs, electroluminescent polymers, MDMO-PPV, PEDOT:PSS, Spin coating, HOMO, LUMO, carrier injection, thermionic emission.
Análisis del gen dhaT en cepas Colombianas de Clostridium sp. (Clostridia) productoras de 1,3-propanodiol.
Authors: Quilaguy Ayure Diana Milena , Montoya Solano José David , Suárez Moreno Zulma Rocío , Bernal Morales José Mauricio , Montoya Castaño Dolly
Published: November 2015

Objective: to analyze the dhaT gene, one of the genes responsible for the 1,3-propanediol (1,3-PD) production, in two native Clostridium strains. Materials and methods: The dhaT gene was amplified by Polimerase Chain Reaction with specific primers designed from Clostridium butyricum VPI1718 operon. Bioinformatics tools like BLASTN, ORF finder, BLASTP and ClustalW were used to determine the identity of the sequence and to assign a function. Results: DNA amplification products were obtained from Colombian Clostridium sp. native strains (IBUN 13A and IBUN 158B) and the Clostridium butyricum DSM 2478 strain, which were sequenced. According to the bioinformatics analysis of the above sequences, a high degree of similarity was found with the dhaT gene of different bacterial species. The highest percentage of identity was obtained with the Clostridium butyricum VPI 1718 strain. Conclusion: knowledge of the physical structure of the 1,3-PD operon in native strains opens the way for developing genetic and metabolic engineering strategies for improving processes productivity.

Key words: 1,3-propanediol, 1,3-propanediol dehydrogenase, dhaT gene, 1,3-propanediol operon.
Relación entre tipo y cantidad de carbohidratos dietarios con el perfil lipídico y ApoB100 en adultos
Authors: Ojeda-Arredondo Myriam , Escobar Juliana , Guerra Martha , Alvarado Martha
Published: November 2015

 Objective. To establish if there is any relationship between the type and amount of dietary carbohydrates commonly consumed and the plasmatic levels of lipids, lipoproteins and apolipoprotein B100 (ApoB100). Materials and methods. The final sample was conformed by the database of 144 lecturers of the Pontificia Universidad Javeriana who had previously participated in another survey and from which we used information on their food habits, plasmatic lipid levels, lipoproteins and ApoB100.  To determine the relationship between the dependent and independent variables, simple and multiple correlation analyses were done. In the cases of no correlation we applied the independence Chi2 test to find the relationship with the consumption of total carbohydrates, sugars and total fiber. Additionally, with a one-factor analysis of variance we compared plasmatic levels of lipids, lipoproteins and ApoB100 with the consumption of total carbohydrates, sugars and fiber. Results. Most of the population consumes above the daily total carbohydrate recommendation, men presented greater carbohydrate consumption of the type of sugars and more elevated plasmatic levels of triglycerides and lipoproteins of very low density (VLDL), whereas women presented higher levels of their high density lipoproteins (HDL). When relating grams of each type of carbohydrates with the levels of lipids, lipoproteins and ApoB100, no significant correlation was found for any of the cases (p>0,05). Conclusion. There was no significant relationship between the type and amount of carbohydrates consumed with the plasmatic levels of lipids, lipoproteins and Apo B100.

Key words: apolipoprotein B100, carbohydrates, plasmatic lipids, lipoproteins.
Efecto de los nutrientes y las condiciones de fermentación en la producción de biosurfactantes con rizobacterias aisladas de fique.
Authors: Sastoque-Cala Leonardo , Cotes-Prado Alba M. , Rodríguez-Vázquez Refugio , Pedroza-Rodríguez Aura M.
Published: November 2015

Objective. To isolate biosurfactant-producing microorganisms from the rhizosphere of fique and to select the best genus to evaluate the effect of nutritional and fermentation conditions on the production of rhamnolipids. Materials and methods. Rhizospheric soil was sampled in three areas of Cauca. The best genus was selected for the experimental designs (Plackett Burman and 22 factorial) and to find the production conditions for the growth kinetics at an Erlenmeyer flask scale. Results. Isolates from the rhizosphere of fique plants were from groups (or genera) of Bacillus, Pseudomonas  and Streptomyces, being Pseudomonas the more responsive in preliminary testing for emulsification. From the results of the experimental designs and the kinetics of production, we found that rhamnose synthesis associated with rhamnolipids (3.2 g/l) and emulsification (68% EC24) was significantly favored (p <0.0001) by cultivating an inoculum of 10% v/v of Pseudomonas fluorescens in a medium composed of: soybean oil 2% (v/v), K2HPO4 0.2% (w/v), yeast extract 0.4 g/l, NH4NO3 3.7 g/l, 1 ml trace elements (CoCl3 20 mg/l, H3BO3 30 mg/l, ZnSO4 10 mg/l, Cu2SO4 1 mg/l, Na2MoO4 3 mg/l, FeSO4 10 mg/l MnSO4 2,6 mg/l) and pH 7.2. Conclusion. Of all the microbial genera isolated from the rhizosphere of fique, Pseudomonas fluorescens had the greatest potential in the production of biosurfactants of the rhamnolipids family.

Key words: Pseudomonas fluorescens, biosurfactant, rhamnose, emulsification index, soybean oil.

 
Evaluación de actividades enzimáticas de Fusarium spp., aislados de lesiones en humanos, animales y plantas
Authors: Valencia-Guerrero María Fernanda , Quevedo-Hidalgo Balkys , Franco-Correa Marcela , Diez-Ortega Hugo , Parra-Giraldo Claudia Marcela , Rodríguez-Bocanegra María Ximena
Published: November 2015

 Objective. To determine amylolytic, cellulolytic, lipolytic, pectinolytic and proteolytic activities in 32 Fusarium spp. isolates from humans, animals and plants. Materials and methods. Qualitative determination of enzymatic activities was done by measuring hydrolysis halos in agar plates with their corresponding substrate. Quantitative determination was done by colorimetric techniques, using liquid culture supernatants to determine the respective substrate degradation. Results. All isolates showed enzymatic activities from a qualitative point of view, except amylolytic and lipolytic. Quantitative determination was possible for all the evaluated enzymes except lipases. Conclusion. The determination of amylolytic, cellulolytic, pectinolytic and proteolytic enzymatic profiles of each of the Fusarium isolates assessed suggests their capacity to degrade these substrates, irrespectively of their origin.

Key words: Fusarium, multihost pathogen, amylases, celluloses, pectinases, proteases, lipases
Rizósfera de árboles acumuladores de fósforo en la amazonia Brasilera.
Authors: Chavez de Oliveira Patricia , Reis de Carvalho Claudio José
Published: November 2015

Objective. With the purpose of knowing the strategies of tolerance of two phosphorus-accumulating species (Neea macrophylla and Cecropia palmate) and a non-accumulating species (Casearia arborea) to phosphorus-deficient soils, we characterized the rhizosphere of these species using a multivariate analysis and correlation matrices in relation to the concentrations of organic phosphorus, available phosphorus, soil organic carbon, organic carbon from  microbial biomass,  acid phosphatase enzyme activity, and root infection by mycorrhizal fungi. Materials and methods. The research was carried out in the Igarapé-Açú town, state of Pará, Brazil in secondary forests with five years of regeneration, where the parameters above mentioned were monitored. Results. Results did not reveal significant differences between the species depending on the characteristics of the soil next to the rhizospheres, suggesting homogeneous conditions. The enzymatic activity was slightly higher in the species with less potential in accumulating P (Casearia arborea) suggesting that efficiency in P use is not determined by the enzymatic activity. Conclusions. Neea macrophylla presented a slightly higher number of mycorrhizal root infections in comparison to the other species, indicating that this could be a tolerance strategy in those environments, while in Cecropia palmata and Casearia arborea it seems that enzymatic activity is the strategy employed.

Key words: acid phosphatase; Brazilian Amazon; rhizosphere
Primer registro de Saprolegnia sp. en una población de anfibios en Colombia.
Authors: Prada-Salcedo Luis Daniel , Franco-Correa Marcela , Acosta-Galvis Andrés Rymel
Published: November 2015

Objective: Most research related to the decline of amphibians has been focused on the detection of the pathogenic fungus Batrachochytrium dendrobatidis. This fungus is the main pathogen detected around the world. However, research has shown the presence of another fungus, Saprolegnia ferax, as a cause of mortality in amphibians in North America. Our study suggests a possible interspecific transmission caused by the presence of rainbow trout; thus, amphibian declines may not be attributable only to the presence of a single pathogen, but to other organisms and factors. Materials and methods: Our study revealed the presence of Saprolegnia sp. in the Andean frog Atelopus mittermeieri using the imprinting technique with lactophenol blue staining, which allowed the typical structures of this fungus to be observed. Results: The importance of this discovery is the presence of two pathogenic fungi, B. dendrobatidis and Saprolegnia, which affecting simultaneously a population of amphibians. This finding brings attention to the eventual presence of other microorganisms that might be involved individually or collectively in the decline of amphibian species. Conclusions: This record suggests a possible transmission between rainbow trout (Oncorhynchus mykiss), an introduced species in the highlands of Colombia, which shares the same habitats with different species of amphibians in the Sanctuary of Flora and Fauna Guanentá in the upper river Fonce in the mid Cordillera Oriental of Colombia.

Key words: decline, Amphibians, Saprolegnia, Fishes, Atelopus, Colombia.

 
Review on hard coral recruitment (Cnidaria: Scleractinia) in Colombia
Authors: Acosta Alberto , Dueñas Luisa F. , Pizarro Valeria
Published: November 2015

Abstract

Recruitment, defined and measured as the incorporation of new individuals (i.e. coral juveniles) into a population, is a fundamental process for ecologists, evolutionists and conservationists due to its direct effect on population structure and function. Because most coral populations are self-feeding, a breakdown in recruitment would lead to local extinction. Recruitment indirectly affects both renewal and maintenance of existing and future coral communities, coral reef biodiversity (bottom-up effect) and therefore coral reef resilience. This process has been used as an indirect measure of individual reproductive success (fitness) and is the final stage of larval dispersal leading to population connectivity. As a result, recruitment has been proposed as an indicator of coral-reef health in marine protected areas, as well as a central aspect of the decision-making process concerning management and conservation. The creation of management plans to promote impact mitigation, rehabilitation and conservation of the Colombian coral reefs is a necessity that requires firstly, a review and integration of existing literature on scleractinian coral recruitment in Colombia and secondly, larger scale field studies. This motivated us to summarize and analyze all existing information on coral recruitment to determine the state of knowledge, isolate patterns, identify gaps, and suggest future lines of research.

Key words: Recruitment, juvenile, coral, Scleractinia, structure, reef, Colombia, density, richness, monitoring.

 
Síntesis y evaluación “in vitro” de la actividad antifúngica de oximas, éteres de oxima e isoxazoles
Authors: Diaz-Velandia John , Durán-Díaz Natalia , Robles-Camargo Jorge , Loaiza Alix Elena
Published: November 2015

Objective. To synthesize and carry out a preliminary evaluation of the in vitro antifungal activity of oximes, oxime ethers and isoxazoles. Materials and methods. Oximes were synthesized from aldehydes or ketones with NH2OH.HCl and K2CO3. Oxime ethers were prepared by alkylation of oximes with propargyl bromide or 2-bromobenzyl bromide, using NaOH as base and acetone as solvent. The isoxazoles were obtained by 1,3-dipolar cycloadditions using ceric ammonium nitrate (CAN), chloramine T (CAT) and NaOCl. Products were identified or characterized using nuclear magnetic resonance (NMR) and mass spectrometry (MS). Radial growth inhibition assays against Aspergillus niger and Fusarium roseum were carried out. Results. Five oximes, seven oxime ethers, four of them new, and four new isoxazoles were obtained. The assessed substances exhibited antifungal activity in amounts of 1,5 mg and 3,0 mg. Conclusions. Although 1,3-dipolar cycloadditions allowed to obtain the desired isoxazoles, this methodology produced a wide variety of side products that reduced yields and made difficult the purification of the target products. Four of the tested compounds showed inhibition percentages greater than 80%.

Key words: oximes, oxime ethers, isoxazoles, antifungal activity.

 
Evaluación del método dilución neutralización aplicado a un desinfectante según la Norma Técnica Colombiana 5473 de 2007
Authors: Arias-Palacios Janeth , Hernandez-Esquivel Libardo , Marín-Díaz Juan Carlos , Navarro-Peña Natalia , Santos-Arévalo Natalia
Published: November 2015

Objective. Evaluate the dilution-neutralization method proposed in the Colombian Technical Norm 5473/07, by using a gel, alcoholbased disinfectant. Materials and methods. This study was done using Pseudomonas aeruginosa ATCC 15442, Staphylococcus aureus ATCC 6538, and Enterococcus hirae ATCC 10541 as the assay microorganisms. The study was carried out at 20±1°C as obligatory temperature and additionally at 36±1°C. Four contact times between microorganisms and the disinfectant were evaluated (0, 2, 5 and 10 minutes). The assay was done both under clean conditions (0.3 g/L of bovine serum albumin), and unclean conditions (3 g/L of bovine serum albumin and 3g/L of sheep erythrocytes). Results. The implementation of this method produced precise results in all of the six
repetitions used during the assay. The obtained results demonstrated a logarithmic reduction higher than five, demonstrating the bactericidal activity exerted by the disinfectant on the control microorganisms. The established experimental conditions and methodology did not affect negatively the growth of any of the strains of microorganisms. Similarly, the neutralizing used did not inhibit the development of the microorganisms of the assay. Conclusions. The method was verified by means of the fulfillment of the limits set by the rule. Our results suggest that the method evaluated by means of the implementation of the protocol established in the Colombian Technical Norm 5473/07, allows evaluating the effectiveness of a disinfectant under selected and controlled experimental conditions.

Key words: disinfection, clean conditions, unclean conditions, dilution-neutralization method, logarithmic reduction.
Estado actual de la resistencia de Helicobacter pylori a tetraciclina: revisión sistemática de la literatura
Authors: Ramírez-Bulla Paola , Mercado-Reyes Marcela , Trespalacios-Rangel Alba Alicia , Avila-Coy Jenny , Otero-Regino William
Published: November 2015

Objective. To determine the prevalence of Helicobacter pylori resistance to and the possible mutations that generate this worldwide resistance. Materials and methods. A systematic search for literature was performed in the databases Medline, Science Direct (Elsevier), Ovid, PubMed, Lilacs
and MedicLatina using relevant key words. Data extraction was independent and checklists were prepared to assess the methodological
quality of the studies. Analysis of information was done with RevMan 5®. Results. We found Helicobacter pylori resistance prevalence rates of 1% for North America, 8% for Central and South America, 5% for Asia, and 2% for Europe. The mutation associated to this resistance is in the 16S rDNA gene at nucleotide position 967TTC to AGA965 responsible of high resistance to tetracycline. Conclusions. Antibiotic resistance is one of the causes most associated to treatment failure in the eradication of Helicobacter pylori, as well as poor adherence to treatment and indiscriminate use of antibiotics. We also evidenced that the rate of tetracycline resistance is higher when
it is used in a second treatment scheme. The distribution of resistance is variable in different areas and it is important to know these resistances to avoid treatment failures.
Key words: Helicobacter pylori, tetracycline, resistance, mutation, treatment, epidemiology, 16S rRNA.
Semi-automatic grading system in histologic and immunohistochemistry analysis to evaluate in vitro chondrogenesis
Authors: Gutiérrez María Lucía , Guevara Johana , Barrera Luis Alejandro
Published: November 2015

During embryological limb formation mesenchymal cells condense and differentiate into chondrocytes, in a process known as chondrogenesis. These chondrocytes synthesize glycosaminoglycans (GAGs), thus playing an important role in this process. A simplified system in vitro chondrogenesis, using adult mesenchymal stromal cells (MSCs) has been demonstrated. This differentiation potential is usually assessed by histological staining. Objective. Establishment of a semi-automatic grading system for histochemistry stains and immunohistochemistry assays. Materials and methods. For chondrogenesis cells were cultured for three weeks in aggregates with inducing media. Total GAGs were measured using dimethylmethylene blue (DMB) method. For histological analyses aggregates were stained with Alcian blue for total GAGs detection and immunohistochemistry (IHC) for aggrecan was performed. Semi-automatic grading for all slides was obtained after ImageJ analysis. Results. MSCs cultured as aggregates in chondrogenic differentiation media had similar protein concentrations for all time points, suggesting cellularity remained homogenous during culture. Total GAGs was higher for aggregates cultured in chondrogenic compared to complete media. The same trend was observed for Alcian blue stain grades by blinded observer and analysis using ImageJ software. Aggrecan’s IHC analysis had a decreasing tendency with time for aggregates in chondrogenic media for blinded observer and ImageJ evaluation. Conclusion. We developed a functional system for semi-automatic slide grading. We corroborated these results by biochemical analysis with comparable results. To our knowledge, for in vitro chondrogenesis, this is the first report to evaluate stains using
this methodology. This procedure might be useful for other applications in the field of Biology and Medical Sciences.
Key words: mesenchymal stromal cells, in vitro chondrogenesis, glycosaminoglycans, ImageJ
Experimentally Derived Kinetic Model for Sensor-Based Gait Monitoring
Authors: Ketema Yohannes , Gebre-Egziabher Demoz
Published: November 2015

A method for estimating gait parameters (shank, thigh, and stance leg angles) from a single, in situ, scalar acceleration measurement is presented. A method for minimizing the impact of errors due to unpredictable variations in muscle actuation and acceleration measurement biases is developed. This is done by determining the most probable gait progression by minimization of a cost function that reflects the size of errors in the gait parameters. In addition, a model for gait patterns that takes into account their variations due to walking speed is introduced and used. The approach is tested on data collected from subjects in a gait study. The approach can estimate limb angles with errors less than 6 deg (one standard deviation) and, thus, is suitable for many envisioned gait monitoring applications in nonlaboratory settings.
Study on the Natural Vibration Characteristics of Flexible Missile With Thrust by Using Riccati Transfer Matrix Method
Authors: Chen Gangli , Rui Xiaoting , Yang Fufeng , Zhang Jianshu
Published: November 2015

Due to the mass consumption and engine thrust of a flexible missile during the powered phase flight, its natural vibration characteristics may be changed significantly. The calculation of natural frequencies and mode shapes plays an important role in the structural design of the missile. Aiming at calculating the natural vibration characteristics of the missile rapidly and accurately, a nonuniform beam subjected to an engine thrust is used to model the free vibration of the missile and Riccati transfer matrix method (RTMM) is adopted in this paper. Numerical results show that the natural frequencies of a typical single stage flexible missile are increased unceasingly in its powered phase, and its mode shapes are changed a lot. When the presented methodology is used to study the natural vibration characteristics of flexible missiles, not only the mass, stiffness, and axial compressive force distributions are described realistically but also numerical stability, high computation speed, and accuracy are achieved.
Characterizations and Correlations of Wall Shear Stress in Aneurysmal Flow
Authors: Arzani Amirhossein , Shadden Shawn C.
Published: November 2015

Wall shear stress (WSS) is one of the most studied hemodynamic parameters, used in correlating blood flow to various diseases. The pulsatile nature of blood flow, along with the complex geometries of diseased arteries, produces complicated temporal and spatial WSS patterns. Moreover, WSS is a vector, which further complicates its quantification and interpretation. The goal of this study is to investigate WSS magnitude, angle, and vector changes in space and time in complex blood flow. Abdominal aortic aneurysm (AAA) was chosen as a setting to explore WSS quantification. Patient-specific computational fluid dynamics (CFD) simulations were performed in six AAAs. New WSS parameters are introduced, and the pointwise correlation among these, and more traditional WSS parameters, was explored. WSS magnitude had positive correlation with spatial/temporal gradients of WSS magnitude. This motivated the definition of relative WSS gradients. WSS vectorial gradients were highly correlated with magnitude gradients. A mix WSS spatial gradient and a mix WSS temporal gradient are proposed to equally account for variations in the WSS angle and magnitude in single measures. The important role that WSS plays in regulating near wall transport, and the high correlation among some of the WSS parameters motivates further attention in revisiting the traditional approaches used in WSS characterizations.
A Biphasic Transversely Isotropic Poroviscoelastic Model for the Unconfined Compression of Hydrated Soft Tissue
Authors: Hatami-Marbini H. , Maulik R.
Published: November 2015

The unconfined compression experiments are commonly used for characterizing the mechanical behavior of hydrated soft tissues such as articular cartilage. Several analytical constitutive models have been proposed over the years to analyze the unconfined compression experimental data and subsequently estimate the material parameters. Nevertheless, new mathematical models are still required to obtain more accurate numerical estimates. The present study aims at developing a linear transversely isotropic poroviscoelastic theory by combining a viscoelastic material law with the transversely isotropic biphasic model. In particular, an integral type viscoelastic model is used to describe the intrinsic viscoelastic properties of a transversely isotropic solid matrix. The proposed constitutive theory incorporates viscoelastic contributions from both the fluid flow and the intrinsic viscoelasticity to the overall stress-relaxation behavior. Moreover, this new material model allows investigating the biomechanical properties of tissues whose extracellular matrix exhibits transverse isotropy. In the present work, a comprehensive parametric study was conducted to determine the influence of various material parameters on the stress–relaxation history. Furthermore, the efficacy of the proposed theory in representing the unconfined compression experiments was assessed by comparing its theoretical predictions with those obtained from other versions of the biphasic theory such as the isotropic, transversely isotropic, and viscoelastic models. The unconfined compression behavior of articular cartilage as well as corneal stroma was used for this purpose. It is concluded that while the proposed model is capable of accurately representing the viscoelastic behavior of any hydrated soft tissue in unconfined compression, it is particularly useful in modeling the behavior of those with a transversely isotropic skeleton.
Enhanced quantum efficiency of photoelectron emission, through surface textured metal electrodes
Authors: Alexander Anna , Moody Nathan A. , Bandaru Prabhakar R.
Published: November 2015

It is predicted that the quantum efficiency (QE) of photoelectron emission from metals may be enhanced, possibly by an order of magnitude, through optimized surface texture. Through extensive computational simulations, it is shown that the absorption enhancement in select surface groove geometries may be a dominant contributor to enhanced QE and corresponds to localized Fabry–Perot resonances. The inadequacy of extant analytical models in predicting the QE increase, and suggestions for further improvement, are discussed.
Effect of extreme ultraviolet photoresist underlayer optical properties on imaging performance
Authors: Kim Jung Sik , Cho Han Ku , Hong Seongchul , Ahn Jinho
Published: November 2015

An extreme ultraviolet lithography (EUVL) suffers from the trade-off relationship among resolution, line edge roughness, and sensitivity, which is a natural limitation for chemically amplified resists. Thus, the performance of photoresist needs to be assisted by the other materials, and the resist underlayer is one of them. Using a lithography simulation tool, the authors show that the standing wave effect can also occur in the EUVL process and is dependent on the pattern pitch ratio. Although underlayers with a lower refractive index exhibit reduced in-plane line edge roughness, the difference between the refractive index of the underlayer and photoresist should be maintained below 5% in order to optimize performance.
Ag films grown by remote plasma enhanced atomic layer deposition on different substrates
Authors: Amusan Akinwumi A. , Kalkofen Bodo , Gargouri Hassan , Wandel Klaus , Pinnow Cay , Lisker Marco , Burte Edmund P.
Published: November 2015

Silver (Ag) layers were deposited by remote plasma enhanced atomic layer deposition (PALD) using Ag(fod)(PEt3) (fod = 2,2-dimethyl-6,6,7,7,8,8,8-heptafluorooctane-3,5-dionato) as precursor and hydrogen plasma on silicon substrate covered with thin films of SiO2, TiN, Ti/TiN, Co, Ni, and W at different deposition temperatures from 70  to 200 °C. The deposited silver films were analyzed by x-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) with energy dispersive x-ray spectroscopy, four point probe measurement, ellipsometric measurement, x-ray fluorescence (XRF), and x-ray diffraction (XRD). XPS revealed pure Ag with carbon and oxygen contamination close to the detection limit after 30 s argon sputtering for depositions made at 120 and 200 °C substrate temperatures. However, an oxygen contamination was detected in the Ag film deposited at 70 °C after 12 s argon sputtering. A resistivity of 5.7 × 10−6 Ω cm was obtained for approximately 97 nm Ag film on SiO2/Si substrate. The thickness was determined from the SEM cross section on the SiO2/Si substrate and also compared with XRF measurements. Polycrystalline cubic Ag reflections were identified from XRD for PALD Ag films deposited at 120 and 200 °C. Compared to W surface, where poor adhesion of the films was found, Co, Ni, TiN, Ti/TiN and SiO2 surfaces had better adhesion for silver films as revealed by SEM, TEM, and AFM images.
Plasma-enhanced atomic layer deposition of titanium oxynitrides films: A comparative spectroscopic and electrical study
Authors: Sowińska Małgorzata , Henkel Karsten , Schmeißer Dieter , Kärkkänen Irina , Schneidewind Jessica , Naumann Franziska , Gruska Bernd , Gargouri Hassan
Published: November 2015

The process parameters' impact of the plasma-enhanced atomic layer deposition (PE-ALD) method on the oxygen to nitrogen (O/N) ratio in titanium oxynitride (TiOxNy) films was studied. Titanium(IV)isopropoxide in combination with NH3 plasma and tetrakis(dimethylamino)titanium by applying N2 plasma processes were investigated. Samples were characterized by the in situ spectroscopic ellipsometry, x-ray photoelectron spectroscopy, and electrical characterization (current–voltage: I-V and capacitance–voltage: C-V) methods. The O/N ratio in the TiOxNy films is found to be very sensitive for their electric properties such as conductivity, dielectric breakdown, and permittivity. Our results indicate that these PE-ALD film properties can be tuned, via the O/N ratio, by the selection of the process parameters and precursor/coreactant combination.
Web-Based Behavioral Intervention Increases Maternal Exercise but Does Not Prevent Excessive Gestational Weight Gain in Previously Sedentary Women
Authors: Smith Katie , Lanningham-Foster L. , Welch Amy , Campbell Christina
Published: November 2015

Background:

Innovative methods are warranted to optimize prenatal outcomes. This study’s objective was to determine if a web-based behavioral intervention (BI) can prevent excessive gestational weight gain (GWG) by increasing physical activity (PA).

Methods:

Participants were randomized to usual care (UC; n = 21) or BI (n = 24) between 10 to 14 weeks gestation. GWG, PA, and diet were assessed at baseline, mid-, and late pregnancy.

Results:

No differences in GWG or adherence to GWG recommendations presented between groups. Total UC MET-minutes significantly decreased from baseline to late-pregnancy (1,234 ± 372 MET-minutes, P = .013). Mid-pregnancy sustained PA was greater for BI than UC (20-minute PA bouts: 122 ± 106 vs. 46 ± 48 minutes/week, P = .005; 30-minute PA bouts: 74 ± 70 vs. 14 ± 24 minutes/week, P < .001), and greater for BI at mid-pregnancy compared with baseline (20-minute PA bouts: 61.3 ± 21.9; 30-minute PA bouts: 39.6 ± 14.8, both P < .05). BI energy intake at mid-pregnancy significantly increased from baseline (336 ± 127 kcals, P = .04) and was significantly greater than UC (2,503 ± 703 vs. 1,894 ± 594, P = .005).

Conclusions:

Sedentary pregnant women should increase PA but may need additional dietary counseling to prevent excessive GWG.
Rate of Physical Activity and Community Health: Evidence From U.S. Counties
Authors: Sato Mikihiro , Du James , Inoue Yuhei
Published: November 2015

Background:

Although previous studies supported the health benefits of physical activity, these studies were limited to individual-level research designs. Building upon a social-ecological model, we examined the relationship between physical activity and community health—the health status of a defined group of people—while accounting for the potential endogeneity of physical activity to health.

Methods:

We obtained U.S. county-level data from the 2012 Behavioral Risk Factor Surveillance System survey and the 2014 County Health Ranking Database. We first conducted an ordinary least squares (OLS) regression analysis to examine the relationship between the rate of physical activity and community health measured by the average perceived health score for each county. We then conducted a 2-stage least squares (2SLS) regression analysis to investigate this relationship after accounting for potential endogeneity.

Results:

Results from the OLS analysis indicated that the rate of physical activity was positively associated with community health. Results from the 2SLS analysis confirmed that the physical activity rate remained positively associated with community health.

Conclusions:

In line with the social-ecological model, our findings provide the first evidence for the health benefits of county-level physical activity. Our results support extant research that has shown relationships between physical activity and individual-level, health-related outcomes.
Muddy clinical waters: a missed betel nut in the bronchus
Authors: Karande Sunil , Vaideeswar Pradeep , Muranjan Mamta
Published: November 2015

A toddler presented with a 5-month history of recurrent episodes of cough, wheezing and fever. Before referral, the toddler had been initially diagnosed as having bronchial asthma and later as having pulmonary tuberculosis. On examination, the patient was febrile and had severe respiratory distress. Chest radiograph and high-resolution CT of the chest revealed collapse of the entire left lung with diffuse bronchiectasis along with a grossly hyperinflated right lung. CT virtual bronchoscopy did not reveal any foreign body. The parents denied any history suggestive of foreign body aspiration and refused consent for rigid bronchoscopy. Nine days after admission, chest physiotherapy was inadvertently prescribed to the patient. Within an hour, the patient experienced acute respiratory deterioration and died. Autopsy revealed a piece of betel nut in the right main bronchus; it had got dislodged from its initial site in the left main bronchus following the chest physiotherapy session.
A dual injury of the shoulder: acromioclavicular joint dislocation (type IV) coupled with ipsilateral mid-shaft clavicle fracture
Authors: Madi Sandesh , Pandey Vivek , Khanna Vikrant , Acharya Kiran
Published: November 2015

A direct blow to the shoulder, as may be sustained in a road traffic accident (RTA), can result in various combinations of fracture dislocations in the shoulder joint complex. Among these, a rare variety is an acromioclavicular joint (ACJ) dislocation coupled with ipsilateral mid-shaft clavicle fracture. Diverse treatment options have been described in the literature, ranging from non-operative and operative, to hybrid management. Treatment for this complex injury is predominantly dictated by the type of dislocation and displacement of the clavicle fracture, as well as age and demand of the patient. Acute high grades of ACJ dislocation require restoration of the coracoclavicular relationship (in place of torn coracoclavicular (CC) ligament) by some form of internal fixation, thereby maintaining the ACJ reduction. An arthroscopic reinstatement of the coracoclavicular relationship using a dog bone button and fibre tape implant for this composite injury pattern has not been previously described. Furthermore, a comprehensive review of the literature associated with this injury pattern is briefly described.
A note on the local relations in geometric formalism of Khovanov homology theory
Authors: Tanaka Kokoro
Published: November 2015

In this short note, we prove that the sphere and 4-tube relations “almost” imply the torus relation in Bar-Natan’s geometric formalism of Khovanov homology theory. As an application, we point out that the invariance and the functoriality can be proved without using the torus relation.
Two roads to the null energy condition
Authors: Parikh Maulik
Published: November 2015

The null energy condition has sweeping consequences in general relativity. I argue here that it has been misunderstood as a property exclusively of matter, when in fact it arises only in a theory of both matter and gravity. I then derive an equivalent geometric formulation of the null energy condition from worldsheet string theory, where it arises beautifully as simple Einstein’s equations in two dimensions. But further, I show that this condition also has a thermodynamic origin, following from a local version of the second law of thermodynamics, applied to gravitational entropy. Thus, far from being an incidental property of matter, the validity of the null energy condition hints at the deep dual origins of gravity.
The Newton primordial atom in superspace-time
Authors: Lasukov Vladimir
Published: November 2015

Quantum solution of differential equations of classical mechanics is found. This solution describes test particle motion in an external gravitational field with the variable passive mass. Theoretical prediction of quintesphere existence in the universe is made.
Effects of Temperature and Hydrogen-Like Impurity on the Vibrational Frequency of the Polaron in RbCl Parabolic Quantum Dots
Authors: Xiao Wei , Xiao Jing-Lin
Published: November 2015

The properties of an electron strongly coupled to longitudinal optical (LO) phonon in RbCl parabolic quantum dot (PQD) with a hydrogen-like impurity at the center were investigated at a finite temperature. We have obtained the vibrational frequency of a strong-coupling polaron in RbCl PQD by using linear combination operator method. We then calculate the effects of temperature, the Coulombic impurity potential and the effective confinement strength on the vibrational frequency by using unitary transformation and the quantum statistics theory methods. The influences of the temperature, the Coulombic impurity potential and the effective confinement strength on the ground state energy and the ground state binding energy are also analyzed. The strengths of these quantities increase with raising temperature. The vibrational frequency is an increasing function of the Coulombic impurity potential and the effective confinement strength. The ground state energy is an increasing function of the effective confinement strength, whereas it is a decreasing one of the Coulombic impurity potential. The ground state binding energy is an increasing function of the Coulombic impurity potential, whereas it is a decayed one of the effective confinement strength.
A modified infeasible interior-point algorithm for P*(κ)-HLCP over symmetric cones
Authors: Pirhaji Mohammad , Mansouri Hossein , Zangiabadi Maryam
Published: November 2015

An improved version of infeasible interior-point algorithm for [Formula: see text] horizontal linear complementarity problem over symmetric cones is presented. In the earlier version (optimization, doi: 10.1080/02331934.2015.1062011) each iteration of the algorithm consisted of one so-called feasibility step and some centering steps. The main advantage of the modified version is that it uses only one feasibility step in each iteration and the centering steps not to be required. Furthermore, giving a complexity analysis of the algorithm, we derive the currently best-known iteration bound for infeasible interior-point methods.
Argument inequalities of certain subclass of multivalent functions defined by using new integral operator
Authors: El-Ashwah R. M. , Hassan A. H.
Published: November 2015

In this paper, we introduce some interesting inequalities regarding the argument of certain p-valent functions. The subclass under investigation is defined by using certain new integral operator. Moreover, special cases and connections of the results presented here with those obtained in earlier works are pointed out.
Generalized distance and new fixed point results
Authors: Rahimi Hamidreza , Soleimani Rad Ghasem , Kumam Poom
Published: November 2015

In this paper, we prove some common fixed point theorems by using the generalized distance in a cone metric space. The results of this paper extend well-known results in the literature.
Chimie douce preparation of reproducible silver coatings for SERS applications
Authors: Sidorov Alexander V. , Grigorieva Anastasia V. , Goldt Anastasia E. , Eremina Olga E. , Veselova Irina A. , Savilov Sergey V. , Goodilin Eugene A.
Published: November 2015

A new soft chemistry preparation method of submicron — thick porous coatings of metallic silver is suggested for possible surface enhanced Raman spectroscopy (SERS) applications. The method is based on facile deposition of diamminesilver (I) aerosols forming instantly a nanostructured layer by fast decomposition and self–reduction of [Ag(NH[Formula: see text] aqueous solutions onto surfaces of inorganic substrates under mild conditions of 280–300[Formula: see text]C in air. A strong difference in overall microstructures and related SERS signals of model analytes is found for substrates with different deposition time and in comparison with a standard magnetron deposition technique. It is demonstrated that the suggested method is predominant for formation of robust SERS substrates with a stable and reproducible SERS enhancement.