bluuebunny/crossref_metadata_2025 huggingface dataset:
Aerosols-cloud microphysics-thermodynamics-turbulence: evaluating supersaturation in a marine stratocumulus cloud
Authors: Ditas F. , Shaw R. A. , Siebert H. , Simmel M. , Wehner B. , Wiedensohler A.
Published: November 2011

Abstract. This work presents a unique combination of aerosol, cloud microphysical, thermodynamic and turbulence parameters to characterize supersaturation fluctuations in a turbulent marine stratocumulus (SC) layer. The analysis is based on observations with the helicopter-borne measurement platform ACTOS and a spectral cloud microphysical parcel model following three different approaches: (1) From the comparison of aerosol number size distributions inside and below the SC layer, the number of activated particles is calculated to 435±87 cm−3 and compares well with the observed median droplet number concentration of Nd=456 cm−3. Furthermore, a 50% activation diameter of Dp50 ≈ 115 nm was derived, which was linked to a critical supersaturation Scrit of 0.16% via Köhler theory. From the shape of the fraction of activated particles, we estimated a standard deviation of supersaturation fluctuations of σS' =0.09%. (2) These estimates are compared to more direct thermodynamic observations at cloud base. Therefore, supersaturation fluctuations (S') are calculated based on highly-resolved thermodynamic data showing a standard deviation of S' ranging within 0.1% ≤ σS' ≤ .3%. (3) The sensitivity of the supersaturation on observed vertical wind velocity fluctuations is investigated with the help of a spectral cloud microphysical model. These results show highest fluctuations of S' with σS' =0.1% at cloud base and a decreasing σS' with increasing liquid water content and droplet number concentration. All three approaches are independent of each other and vary only within a factor of about two.
Quasi-linear dynamics of Weibel instability
Authors: Pokhotelov O. A. , Amariutei O. A.
Published: November 2011

Abstract. The quasi-linear dynamics of resonant Weibel mode is discussed. It is found that nonlinear saturation of Weibel mode is accompanied by substantial modification of the distribution function in resonant region. With the growth of the wave amplitude the parabolic bell-like form of the electron distribution function in this region converts into flatter shape, such as parabola of the fourth order. This results in significant weakening of the resonant interaction of the wave with particles. The latter becomes weaker and then becomes adiabatic interaction with the bulk of the plasma. This is similar to the case of Bernstein-Greene-Kruskal (Bernstein et al., 1957) electrostatic waves. The mathematical similarity of the Weibel and magnetic mirror instabilities is discussed.
Landscape patterns of soil oxygen and atmospheric greenhouse gases in a northern hardwood forest landscape
Authors: Werner S. F. , Driscoll C. T. , Groffman P. M. , Yavitt J. B.
Published: November 2011

Abstract. The production and consumption of the greenhouse gases, carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4), are controlled by redox reactions in soils. Together with oxygen (O2), seasonal and spatial dynamics of these atmospheric gases can serve as robust indicators of soil redox status, respiration rates, and nitrogen cycling. We examined landscape patterns of soil oxygen and greenhouse gas dynamics in Watershed 3 at the Hubbard Brook Experimental Forest, NH, USA. We analyzed depth profiles of soil O2, CO2, N2O, and CH4 approximately bimonthly for one year. Soil gas depth profiles were obtained from several different soil types encompassing a range of topographic positions, drainage classes, and organic matter content. Soil O2 was a good predictor of greenhouse gas concentrations. Unsaturated soils always had O2 concentrations >18 %, while saturated soils had O2 ranging from 0 to 18 %. For unsaturated soils, changes in CO2 were nearly stoichiometric with O2. High concentrations of CH4 (>10 μL L−1) were typically associated with saturated soils; CH4 was typically below atmospheric concentrations (<1.8 μL L−1) in unsaturated soils. High concentrations of N2O (>5000 nL L−1) were found only in well-aerated soils after summer rainfall events and in marginally-anoxic soils; N2O was consumed (<200 nL L−1) under anoxic conditions. The production and consumption of greenhouse gases were linked to functionally distinct biogeochemical zones of variable redox conditions (hotspots), which exhibit dynamic temporal patterns of redox fluctuations (hot moments). These soil redox hot phenomena were temporally driven by climate and spatially organized by soil type (reflective of topographic position) further constrained by subsurface hydrology.
Assessing the hydrodynamic boundary conditions for risk analyses in coastal areas: a stochastic storm surge model
Authors: Wahl T. , Mudersbach C. , Jensen J.
Published: November 2011

Abstract. This paper describes a methodology to stochastically simulate a large number of storm surge scenarios (here: 10 million). The applied model is very cheap in computation time and will contribute to improve the overall results from integrated risk analyses in coastal areas. Initially, the observed storm surge events from the tide gauges of Cuxhaven (located in the Elbe estuary) and Hörnum (located in the southeast of Sylt Island) are parameterised by taking into account 25 parameters (19 sea level parameters and 6 time parameters). Throughout the paper, the total water levels are considered. The astronomical tides are semidiurnal in the investigation area with a tidal range >2 m. The second step of the stochastic simulation consists in fitting parametric distribution functions to the data sets resulting from the parameterisation. The distribution functions are then used to run Monte-Carlo-Simulations. Based on the simulation results, a large number of storm surge scenarios are reconstructed. Parameter interdependencies are considered and different filter functions are applied to avoid inconsistencies. Storm surge scenarios, which are of interest for risk analyses, can easily be extracted from the results.
Clinical Resolution of Nasal Aspergillosis Following Therapy with a Homeopathic Remedy in a Dog
Authors: Epstein Shelley , Hardy Robert
Published: November 2011

A 6 yr old, male, neutered Weimaraner was treated homeopathically for nasal aspergillosis after failing to respond to two treatments of topical (intranasal) clotrimazole and oral amoxicillin trihydrate/clavulanate potassium. Computed tomography, rhinoscopy, fungal culture, and cytology previously confirmed the diagnosis. At presentation for homeopathic treatment, the dog had aggressive left-sided sinusitis and rhinitis with destruction of nasal turbinates and severe bouts of epistaxis. Erosion and depigmentation of the nasal planum were evident. After two treatments with homeopathic aurum metallicum, resolution of clinical signs occurred and clearance of the aspergillosis organisms was documented by computed tomographic scan, rhinoscopy, and histopathology. Homeopathic aurum metallicum may be beneficial in treating cases of canine nasal aspergillosis.
Canine Schistosomiasis in Kansas: Five Cases (2000–2009)
Authors: Hanzlicek Andrew S. , Harkin Kenneth R. , Dryden Michael W. , Chun Ruthanne , Payne Patricia A. , Nietfeld Jerome C. , Debey Brad M.
Published: November 2011

This is a retrospective case series consisting of five dogs diagnosed with schistosomiasis. The purpose of this article is to report the presence of naturally occurring canine schistosomiasis in Kansas and to provide clinical details regarding schistosomiasis. Medical records of dogs diagnosed with schistosomiasis from 2000 to 2009 were reviewed, and information extracted included signalment, history, clinical signs, diagnostic test results, treatment, and outcome. Affected dogs were primarily medium to large breed and young to middle aged. All dogs were considered outdoor dogs, with three having known access to surface water. Common clinical signs included gastrointestinal disease and signs associated with hypercalcemia. Fecal flotation was negative in all dogs in contrast to fecal saline sedimentation and fecal polymerase chain reaction, which were both positive in all dogs in which it was performed. All dogs treated specifically for schistosomiasis fully recovered. This article describes the first reported cases of canine schistosomiasis in the Midwest and the first reported case of intestinal intussusception secondary to schistosomiasis. Recognizing that canine schistosomiasis is present in Kansas and possibly other Midwestern states should prompt veterinarians to perform appropriate diagnostic investigation in suspect animals as the diagnosis is straight forward and relatively inexpensive.
Endoscopic Diagnosis of a Pylorogastric Intussusception with Spontaneous ResolutionS
Authors: de Brito Galvao Joao Felipe , Johnson Susan E. , Sherding Robert G. , Baan Mieke , Ball Rebecca L. , Ben-Amotz Ron
Published: November 2011

A 7 mo old intact female golden retriever was evaluated for acute vomiting. Abdominal radiographs revealed a possible gastric foreign body. Upper gastrointestinal endoscopy revealed an edematous, tubular antral mass, which on further evaluation was determined to be a pylorogastric intussusception based on radiographic, endoscopic, and surgical findings. Spontaneous resolution of the intussusception occurred upon surgical exploration of the abdomen. Histopathology of a full-thickness gastric biopsy revealed vascular congestion consistent with an intussusception, but did not indicate the primary cause. The dog recovered uneventfully from surgery and had no further vomiting during the 6 mo follow-up period. This case was significant as it was the first report of pylorogastric intussusception diagnosed using endoscopy. This description of the unique endoscopic appearance of pylorogastric intussusception will be useful for the veterinary endoscopist.
Two Cases of Paraprostatic Cysts in Castrated Male Dogs
Authors: Goodrich Zachary J. , Wilke Vicki L. , Root Kustritz Margaret V.
Published: November 2011

Two castrated male dogs presented for evaluation of tenesmus. Presurgical evaluations included complete physical examinations, serum biochemistry, abdominal ultrasonography, and MRI (case 2 only). Paraprostatic cysts were diagnosed in both cases based on the results of abdominal ultrasonography, MRI, and histopathology of tissue samples obtained during exploratory laparotomy. To the authors' knowledge, the two cases presented herein are the first documented cases of paraprostatic cysts that developed after castration in male dogs. Paraprostatic cysts should be considered in the differential diagnoses for castrated male dogs with prostatic disease.
Remifentanil/Isoflurane Anesthesia in Five Dogs with Liver Disease Undergoing Liver Biopsy
Authors: Anagnostou Tilemahos L. , Kazakos George M. , Savvas Ioannis , Papazoglou Lysimachos G. , Rallis Timoleon S. , Raptopoulos Dimitris
Published: November 2011

Remifentanil is a synthetic opioid with direct action on μ opioid receptors. It has an ultrashort duration of action, and its elimination is independent of hepatic or renal function. The anesthetic management of five dogs with nonuniform liver disease and requiring liver biopsy via celiotomy is described. Remifentanil and isoflurane were used for induction and maintenance of anesthesia. Intraoperative analgesia was provided by a constant rate infusion of remifentanil. Remifentanil, in combination with isoflurane, was safely and successfully used in five cases for the balanced anesthesia of dogs with hepatic diseases requiring liver biopsy via celiotomy.
Presurgical Antiseptic Efficacy of Chlorhexidine Diacetate and Providone-Iodine in the Canine Preputial Cavity
Authors: Neihaus Steven A. , Hathcock Terri L. , Boothe Dawn M. , Goring Robert L.
Published: November 2011

Antiseptic flushing of the canine prepuce and its exclusion from the surgical field are recommended before abdominal surgery to reduce the risk of bacterial contamination. The authors cultured the preputial cavity of 60 dogs prior to and following flushing with 0.05% chlorhexidine diacetate, 1% povidone-iodine, or 0.9% saline control. Bacterial growth was evaluated using a semiquantitative method, and bacterial organisms were subsequently identified. There were no significant differences between povidone-iodine and the saline control in any of the variables assessed. Chlorhexidine resulted in a significant decrease in the proportion of positive postflush cultures compared with povidone-iodine. Although not significant, the difference in adverse reactions between povidone-iodine (25%) and chlorhexidine diacetate (5%) suggests clinical relevance. Based on the results of this study, a 2 min flush with 0.05% chlorhexidine diacetate is recommended for presurgical preparation of the preputial cavity.
Severe Ulcerative and Granulomatous Pinnal Lesions with Granulomatous Sebaceous Adenitis in Unrelated Vizslas
Authors: Zur Gila , Botero-Anug Ana-Maria
Published: November 2011

Granulomatous sebaceous adenitis (GSA) is uncommon in dogs; however, certain breed predilections exist. In this report, three cases of GSA in unrelated vizslas have been described. All cases initially presented with episodes of otitis externa followed by severe inner pinnal lesions. In one case, multifocal coalescing inner pinnal ulceration appeared 4 wk prior to the occurrence of the skin lesions. The other two cases presented with simultaneous pinnal and skin lesions following episodes of bilateral otitis. The pinnae were diffusely erythematous and had multiple coalescing erosions and ulcers. The body lesions consisted of multifocal alopecia, papules, and fine scales. Biopsies of the skin and pinnae confirmed GSA. Two dogs responded to treatment with synthetic retinoids and cyclosporin A, respectively. One dog was not treated, and the owners preferred euthanasia when the ear lesions recurred and did not respond to glucocorticoids. To the best of the authors’ knowledge, GSA with multifocal coalescing ulcerative pinnal lesions has not previously been reported.
Aptamer-based modulation of blood coagulation
Authors: Rohrbach F. , Pötzsch B. , Müller J. , Mayer G.
Published: November 2011

Nucleic acid based aptamers are singlestranded oligonucleotide ligands isolated from random libraries by an in-vitro selection procedure. Through the formation of unique three-dimensional structures, aptamers are able to selectively interact with a variety of target molecules and are therefore also promising candidates for the development of anticoagulant drugs. While thrombin represents the most prominent enzymatic target in this field, also aptamers directed against other coagulation proteins and proteases have been identified with some currently being tested in clinical trials.

In this review, we summarize recent developments in the design and evaluation of aptamers for anticoagulant therapy and research.
Murine Embryonic Stem Cell Derivation, In Vitro Pluripotency Characterization, and In Vivo Teratoma Formation
Authors: Chou Yu‐Fen , Yabuuchi Akiko
Published: November 2011

The derivation of embryonic stem (ES) cells represents one of the most important breakthroughs in mammalian developmental biology. In addition to their utility in a wide array of in vitro studies, ES cells are also one of the most useful starting materials for the generation of mutants by homologous recombination in mice (Thomson and Solter, 1988). When ES cells are injected into host blastocysts and transferred to the uterus of a pseudo‐pregnant mouse, they can contribute to different types of tissues in chimeric mice, including the germ line (Bradley et al., 1984). Hundreds of genes have been studied through genetic manipulation of ES cells to model human genetic diseases. In this unit, the ES cell lines are derived from the 129SvEv mice strain, which has a high probability of promoting germ line transmission. Procedures for validating and characterizing ES cell pluripotency are also described in detail. Curr. Protoc. Toxicol. 50:2.22.1‐2.22.13. © 2011 by John Wiley & Sons, Inc.
Preparation of Epithelial and Mesenchymal Stem Cells from Murine Mammary Gland
Authors: Guest Ian , Ilic Zoran , Ma Jun
Published: November 2011

The mammary gland is a complex organ consisting of multiple cell types that undergo extensive remodeling during pregnancy and involution, cyclical changes that suggest the existence of a resident stem cell population that is responsible for remarkable tissue regeneration. The basic functional unit of the mammary gland is the terminal duct lobular unit, which invades the stromal tissue (fat, connective tissue, blood vessels, etc.). Luminal epithelial cells line the ducts while outer myoepithelial cells secrete the basal lamina that separates the mammary gland parenchyma from the mesenchymal cells of the stroma. Within the epithelial cell population of the ducts resides the mammary gland stem cells and it is believed that this population is the origin of the mammary gland cancer stem cells as well. In the mouse, epithelial stem cells can be separated from mesenchymal cells on the basis of CD24, CD44, and CD49f expression. This allows for the determination of both normal and cancer stem cell potential of these two populations and permits investigation into their interaction in tumor development. Curr. Protoc. Toxicol. 50:22.3.1‐22.3.15. © 2011 by John Wiley & Sons, Inc.
Variation in initial kidney replacement therapy for end‐stage renal disease due to lupus nephritis in the United States
Authors: Devlin Amy , Waikar Sushrut S. , Solomon Daniel H. , Lu Bing , Shaykevich Tamara , Alarcón Graciela S. , Winkelmayer Wolfgang C. , Costenbader Karen H.
Published: November 2011

Objective

Little is known about the patterns of use of initial kidney replacement therapies among patients with lupus nephritis (LN) end‐stage renal disease (ESRD). We aimed to identify sociodemographic and clinical factors associated with variation in initial kidney replacement therapies among LN ESRD patients.

Methods

Patients with incident LN ESRD (1995–2006) were identified in the US Renal Data System. Age, sex, race, ethnicity, medical insurance, employment status, residential region, clinical factors, and comorbidities were considered as potential predictors of ESRD treatment choice, i.e., peritoneal dialysis (PD), hemodialysis (HD), or preemptive kidney transplantation in age‐adjusted and multivariable‐adjusted logistic regression analyses.

Results

Of the 11,317 individuals with incident LN ESRD, 82.0% initiated HD, 12.2% initiated PD, and 2.8% underwent preemptive kidney transplantation. Receiving initial PD was significantly associated with earlier calendar year, female sex, higher albumin and hemoglobin levels, and lower serum creatinine levels. African Americans (versus whites), Medicaid beneficiaries and those with no health insurance (versus private insurance), and those unemployed (versus employed) had significantly reduced PD initiation. Comorbidities including congestive heart failure, peripheral vascular disease, and the inability to ambulate were also associated with decreased PD. Many sociodemographic and clinical factors favoring PD were associated with preemptive kidney transplant (versus dialysis) as well.

Conclusion

Few patients with LN ESRD receive initial PD or preemptive kidney transplantation. Race, ethnicity, employment, and medical insurance type are strongly associated with initial kidney replacement therapy choice. Future studies need to investigate the appropriateness of sociodemographic and clinical variation and the comparative effectiveness of kidney replacement therapies for LN ESRD.
Investigation of the rheological, dynamic mechanical, and tensile properties of single‐walled carbon nanotubes reinforced poly(vinyl chloride)
Authors: Abu‐Abdeen M.
Published: November 2011

Polymer nanocomposites consisting of single‐walled carbon nanotubes (SWCNTs) and poly(vinyl chloride) were prepared by casting technique. The complex viscosity increased with increasing SWCNTs content, and it had a percolation concentration threshold equal to 0.45 wt % of SWCNTs. The storage modulus, G′, increased with increasing either SWCNTs content or frequency. A gradual decrease in the terminal zone slope of G′ for the nanocomposites with increasing SWCNTs content may be explained by the fact that the nanotube–nanotube interactions will be dominant at higher CNTs content, and lead to the formation of the interconnected or network‐like structures of SWCNTs in the polymer nanocomposites. The rheological loss factor indicates two relaxation peaks at frequencies of 0.11 and 12.8 Hz due to the interaction between SWCNTs and polymer chains and glass transition, respectively. Dynamic mechanical properties were measured for the prepared composites. The results indicate that the storage modulus changes steadily, and the tanδ peaks are less intense for high SWCNTs content. Tensile tests were measured and depicted by an increase in the elastic modulus with increasing SWCNTs content, but it decreases for all composites as the testing temperature increased. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synthesis of polyaniline nanostructures in micellar solutions
Authors: El‐Dib Fawzia. I. , Sayed Wafaa M. , Ahmed Sahar. M. , Elkodary Mohamed
Published: November 2011

Polymerization of aniline nanoparticles was carried out in aqueous micellar solutions of surfactants, including anionic (sodium dodecyl sulfate), nonionic (nonyl phenol ethoxylate), and cationic (cetyltrimethyl ammonium bromide) surfactants. The size and morphology of these synthesized PANI nanoparticles strongly depended on the structure of the surfactants used in the formation of micelles, as shown by transmission electron microscopy. Scanning electron microscopy, Fourier transform infrared spectroscopy, and X‐ray diffraction were used in the characterization of the synthesized PANI nanoparticles. The PANI nanoparticles revealed enhanced conductivity compared to conventional bulk PANI. In addition PANI–poly(methyl methacrylate) (PMMA) nanocomposites were synthesized. The results revealed that the PMMA nanoparticles retarded thermal decomposition and enhanced the conductivities compared with pristine PANI nanoparticles. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
A Novel Fuzzy Approach for State Estimation of Nonlinear Hybrid Systems Using Particle Filtering Method
Authors: Salahshoor Karim , Samadi M. Foad
Published: November 2011

Reliable state estimation is challenging for nonlinear hybrid systems. Particle filtering has emerged as an appealing approach for online hybrid state estimation. Mode detection in nonlinear hybrid systems is, however, a troublesome issue for the conventional particle filter mainly due to sample impoverishment. The problem is also exacerbated when dynamics that govern healthy or faulty modes are close together. False mode detection consequently leads to erroneous continuous state estimation. This paper proposes a novel fuzzy‐based particle filter to reduce continuous state estimation errors due to failures in mode detection. It is fulfilled by considering a fuzzified contribution of each feasible mode in overall estimation. In addition, two new resampling strategies are presented to tackle the degeneracy problem. A set of simulation test studies are conducted to extract the characteristic features and evaluate the performance of the proposed algorithm compared to observation and transition‐based most likely modes tracking particle filter (OTPF) as one of the most meticulous proposed estimation algorithms. The simulation results demonstrate the superior efficiency of the algorithm in dealing with the considered potential estimation problems.
Parametric design approach for proportional multiple‐integral derivative observers in descpriptor linear systems
Authors: Wu Ai‐Guo , Duan Guang‐Ren , Hou Ming‐Zhe
Published: November 2011

A new type of observer for descriptor linear systems, proportional multiple‐integral derivative (PMID) observers, is proposed in this paper. A parametric design approach for such observer is established. The proposed approach gives the complete parameterizations for all the observer gain matrices, realizes the elimination of impulsive behaviors, and guarantees the regularity of the observer systems. A numerical example is provided to show the design procedure and illustrate the effectiveness of the presented approach.
A sensitive method for determination of furanodiene in rat plasma using liquid chromatography/tandem mass spectrometry and its application to a pharmacokinetic study
Authors: Pei Lixia , Liu Sheng , Zheng Jin , Chen Xiuping
Published: November 2011

Furanodiene, a sesquiterpene component extracted from the essential oil of the rhizome of Curcuma wenyujin Y.H. Chen et C. Ling (Wen Ezhu), is widely used in traditional Chinese medicine. A sensitive analytical method was established and validated for furanodiene in rat plasma, which was further applied to assess the pharmacokinetics of furanodiene in rats receiving a single dose of furanodiene. Liquid chromatography tandem mass spectrometry (LC/MS/MS) in multiple reaction monitoring mode was used in the method and costundide was used as internal standard. A simple protein precipitation based on methanol was employed. The simple sample cleanup increased the throughput of the method substantially. The method was validated over the range of 1–1000 ng/mL with a correlation coefficient >0.99. The lower limit of quantification was 1 ng/mL for furanodiene in plasma. Intra‐ and inter‐day accuracies for furanodiene were 88–115 and 102–107%, and the inter‐day precision less than 14.4%. After a single oral dose of 10 mg/kg of furanodiene, the mean peak plasma concentration of furanodiene was 66.9 ± 23.4 ng/mL at 1 h, the area under the plasma concentration–time curve (AUC0–10 h) was 220 ± 47.8 h ng/mL, and the elimination half‐life was 1.53 ± 0.06 h. After an intravenous adminstration of furanodiene at a dosage of 5 mg/kg, the area under the plasma concentration–time curve was 225 ± 76.1 h⋅ng/mL, and the elimination half‐life was 2.40 ± 1.18 h. Based on this result, the oral bioavailability of furanodiene in rats at 10 mg/kg is 49.0%. Copyright © 2011 John Wiley & Sons, Ltd.
Quantitative determination of tiopronin in human plasma by LC‐MS/MS without derivatization
Authors: Yuan Bo , Zhai Nannan , Jiang Xue , Jin Yi , Liu Chunling , Li Chibing , Xu Haiyan
Published: November 2011

Tiopronin (TP) is a synthetic thiol compound without chromophore. By optimizing the chromatographic conditions and sample preparation processes, an improved LC‐MS/MS analytical method without derivatization has been developed and validated to determine TP concentrations in human plasma. After reduction with 1,4‐dithiothreitol, plasma samples were deproteinized with 10% perchloric acid. The post‐treatment samples were analyzed on a C8 column interfaced with a triple quadrupole tandem mass spectrometer in negative electrospray ionization mode. Methanol–5 mmol/L ammonium acetate (20:80, v/v) was used as the isocratic mobile phase. The assay was linear over the concentration range of 40.0–5000 ng/mL. The intra‐ and inter‐day precisions were within 12.9% in terms of relative standard deviation and the accuracy within 5.6% in terms of relative error. This simple and sensitive LC‐MS/MS method with short analytical time (3.5 min each sample) was successfully applied to the pharmacokinetic study of TP in healthy Chinese male volunteers after an oral dose of 300 mg TP. Copyright © 2011 John Wiley & Sons, Ltd.
Photoactivatable Caged Cyclic RGD Peptide for Triggering Integrin Binding and Cell Adhesion to Surfaces
Authors: Wirkner Melanie , Weis Simone , San Miguel Verónica , Álvarez Marta , Gropeanu Radu A. , Salierno Marcelo , Sartoris Anne , Unger Ronald E. , Kirkpatrick C. James , del Campo Aránzazu
Published: November 2011

We report the synthesis and properties of a photoactivatable caged RGD peptide and its application for phototriggering integrin‐ and cell‐binding to surfaces. We analysed in detail 1) the differences in the integrin‐binding affinity of the caged and uncaged forms by quartz crystal microbalance (QCM) studies, 2) the efficiency and yield of the photolytic uncaging reaction, 3) the biocompatibility of the photolysis by‐products and irradiation conditions, 4) the possibility of site, temporal and density control of integrin‐binding and therefore human cell attachment, and 5) the possibility of in situ generation of cell patterns and cell gradients by controlling the UV exposure. These studies provide a clear picture of the potential and limitations of caged RGD for integrin‐mediated cell adhesion and demonstrate the application of this approach to the control and study of cell interactions and responses.
Influence of Sugar Ring Conformation on the Transportability of Nucleosides by Human Nucleoside Transporters
Authors: Damaraju Vijaya L. , Mowles Delores , Smith Kyla M. , Yao Sylvia Y. M. , Young James D. , Marquez Victor E. , Cass Carol E.
Published: November 2011

The conformational preference of human nucleoside transporters (hNTs) with respect to sugar ring was examined using conformationally fixed purine and pyrimidine nucleosides built on a bicyclo[3.1.0]hexane template. These fixed‐conformation nucleosides, methanocarba‐deoxyadenosine or methanocarba‐deoxycytidine in North (C3′‐endo, N‐MCdA and N‐MCdC) or South (C2′‐endo, S‐MCdA and S‐MCdC) conformations, were used to study inhibition of equilibrative (hENT1–4) and concentrative (hCNT1–3) nucleoside transport by individual recombinant hNTs produced in Saccharomyces cerevisiae cells or Xenopus laevis oocytes. Our results indicated that nucleosides in the North conformation were potent inhibitors of transport mediated by hCNTs whereas South nucleosides were inhibitors of hENTs, thus showing differences in the interaction with the hNTs. In summary, hCNTs exhibited strong preferences for North nucleosides whereas hENTs exhibited slight preferences for South nucleosides, demonstrating for the first time different conformational preferences among members of the two families of hNTs.
A non‐linear homogeneous model for bone‐like materials under compressive load
Authors: Mengoni M. , Voide R. , de Bien C. , Freichels H. , Jérôme C. , Léonard A. , Toye D. , Müller R. , van Lenthe G. H. , Ponthot J. P.
Published: November 2011

Finite element (FE) models accurately compute the mechanical response of bone and bone‐like materials when the models include their detailed microstructure. In order to simulate non‐linear behavior, which currently is only feasible at the expense of extremely high computational costs, coarser models can be used if the local morphology has been linked to the apparent mechanical behavior. The aim of this paper is to implement and validate such a constitutive law. This law is able to capture the non‐linear structural behavior of bone‐like materials through the use of fabric tensors. It also allows for irreversible strains using an elastoplastic material model incorporating hardening. These features are expressed in a constitutive law based on the anisotropic continuum damage theory coupled with isotropic elastoplasticity in a finite strain framework. This material model was implemented into metafor (LTAS‐MNNL, University of Liège, Belgium), a non‐linear FE software. The implementation was validated against experimental data of cylindrical samples subjected to compression. Three materials with bone‐like microstructure were tested: aluminum foams of variable density (ERG, Oakland, CA, USA), polylactic acid foam (CERM, University of Liège, Liège, Belgium), and cancellous bone tissue of a deer antler (Faculty of Veterinary Medicine, University of Liège, Liège, Belgium). Copyright © 2011 John Wiley & Sons, Ltd.
Changes in expression profiles of antioxidant enzymes in diabetic rat kidneys
Authors: Sadi Gökhan , Eryilmaz Nihan , Tütüncüoğlu Egemen , Cingir Şahika , Güray Tülin
Published: November 2011

Background

In diabetes mellitus, increased formation of reactive oxygen species due to high level of glucose in both blood plasma and tissues creates oxidative stress and damages the tissues. Antioxidants together with the antioxidant enzymes are very important in order to protect the cells against oxidative damage.

Methods

Differential expressions of both mRNA and proteins of major antioxidant enzymes in streptozotocin‐induced diabetic rat kidneys were measured with the help of real‐time polymerase chain reaction and western blot analysis, respectively. Furthermore, effects of two strong antioxidants α‐lipoic acid, vitamin C and their combination on the regulation of both expressions and the activities of antioxidant enzymes were also studied.

Results

In diabetic rat kidney tissue, both catalase and glutathione peroxidase activities were reduced (although mRNA expression for both was greatly increased) when compared with controls. No significant change was observed in superoxide dismutase (SOD) activity. Alpha‐lipoic acid increased catalase activity towards the control values. Combined administration of alpha‐lipoic acid and vitamin C increased the activities of both catalase and SOD, demonstrating a posttranslational effect. Glutathione concentrations were decreased in diabetic kidney; alpha‐lipoic acid treatment partially restored the glutathione levels.

Conclusions

All data showed the importance of post‐transcriptional and translational regulation of the antioxidant enzyme activities against oxidative stress that is associated with diabetes. Copyright © 2011 John Wiley & Sons, Ltd.
MCS9.7 enhancer activity is highly, but not completely, associated with expression of Irf6 and p63
Authors: Fakhouri Walid D. , Rhea Lindsey , Du Tianli , Sweezer Eileen , Morrison Harris , Fitzpatrick David , Yang Baoli , Dunnwald Martine , Schutte Brian C.
Published: November 2011

Background: DNA variation in Interferon Regulatory Factor 6 (IRF6) contributes risk for orofacial clefting, including a common DNA variant rs642961. This DNA variant is located in a multi‐species conserved sequence that is 9.7 kb upstream from the IRF6 transcriptional start site (MCS9.7). The MCS9.7 element was shown to possess enhancer activity that mimicked the expression of endogenous Irf6 at embryonic day 11.5 in transient transgenic embryos, and also contains a p63 binding site that transactivates IRF6 expression. To analyze whether the MCS9.7 enhancer is sufficient to drive IRF6 expression, we generated stable transgenic murine lines that carry a MCS9.7‐lacZ transgene. We hypothesized that MCS9.7 was sufficient to recapitulate the endogenous expression of Irf6 at other time‐points during embryonic development. Results: We observed that MCS9.7 activity recapitulated endogenous Irf6 expression in most tissues, but not in the medial edge epithelium (MEE) at E14.5, when Irf6 expression was high during secondary palatal fusion. Also, while MCS9.7 activity and Irf6 expression were associated with p63 expression, we observed MCS9.7 activity and Irf6 expression in periderm, although p63 was absent. Conclusion: These data suggest that MCS9.7 enhancer activity is not sufficient to recapitulate IRF6 expression, and that p63 expression is not always necessary nor sufficient for transactivation of IRF6. Developmental Dynamics 241:340–349, 2012. © 2011 Wiley Periodicals, Inc.
An in vivo map of bone morphogenetic protein 2 post‐transcriptional repression in the heart
Authors: Kruithof Boudewijn P. T. , Xu Junwang , Fritz David T. , Cabral Carolina S. , Gaussin Vinciane , Rogers Melissa B.
Published: November 2011

Coronary artery sections from day 13.5 transgenic mouse pups were stained by immuno‐fluorescence for a‐smooth muscle actin (red) and counterstained with DAPI (green) to mark nuclei. The blue, β‐galactosidase‐positive cells express a Bmp2‐driven lacZ reporter gene that lacks a post‐transcriptional repressor conserved from mammals to fishes. See Kruithof et al., An In Vivo Map of Bone Morphogenetic Protein 2 Post‐transcriptional Repression in the Heart.
Controllable Synthesis of Single‐Crystalline Fe3O4 Nanorice by a One‐Pot, Surfactant‐Assisted Hydrothermal Method and Its Properties
Authors: Rajendran Ramesh , Muralidharan Rajalakshmi , Santhana Gopalakrishnan Ramya , Chellamuthu Muthamizhchelvan , Ponnusamy Suruttaiya U. , Manikandan Elayaperumal
Published: November 2011

Single‐crystalline Fe3O4 nanorice has been prepared by a simple one‐pot, surfactant‐assisted hydrothermal method using dodecyltrimethylammonium bromide (DTAB) as a surfactant. X‐ray powder diffraction, field emission scanning electron microscopy (FESEM), TEM, high‐resolution (HR)TEM, micro‐Raman spectroscopy and magnetic measurements have been employed to study the properties of the product. The importance of NaAc and ethylene glycol in the formation of the pure magnetite phase has been established. The as‐synthesized products have a regular rice‐like shape with an average diameter of 150 nm and length of 500 nm and are monodisperse. Shape evolution from cauliflower‐ to rice‐like morphology has been achieved by controlling the DTAB concentration. A possible formation mechanism for the Fe3O4 nanorice is explored. Furthermore, the product showed ferromagnetic properties at room temperature.
The Shortest Strategy for Generating Phosphonate Prodrugs by Olefin Cross‐Metathesis – Application to Acyclonucleoside Phosphonates
Authors: Pradère Ugo , Clavier Hervé , Roy Vincent , Nolan Steven P. , Agrofoglio Luigi A.
Published: November 2011

A short synthetic route to phosphonate prodrugs by olefin cross‐metathesis, which uses either (acyloxymethyl) or (hexadecyloxypropyl) allylphosphonate building blocks is described. A study of eight ruthenium catalysts including the Ru–indenylidene catalyst, which bears the N‐heterocyclic carbene 1,3‐bis(2,6‐diisopropylphenyl)‐4,5‐dihydroimidazol‐2‐ylidene, was undertaken. This method was applied to the synthesis of acyclonucleoside phosphonate prodrugs. This strategy is appealing for further uses in pharmaceutical and medicinal research.
Synthesis of Chiral Benzoxa(thia)zepine and Pyridoxazepine Derivatives Using Palladium‐Catalyzed Intramolecular Aryl Amination Reaction
Authors: Das Adhikary Nirmal , Chattopadhyay Partha
Published: November 2011

A palladium‐catalyzed method employing different bulky biaryl phosphanes as ligands has been developed for the intramolecular amination of aryl bromides and iodides. A variety of aryl halide substrates have been aminated through the intramolecular pathway in good yield using different sugar‐derived amines to give furo‐benzoxa(thia)zepine and pyridoxazepine derivatives. The method is capable of furnishing chiral, enantiopure benzoxa(thia)zepines and pyridoxazepines of significant biological importance.
1,3‐Benzyl Migration in Iminium Ions: Evidence for a Fast Free‐Radical Chain Reaction
Authors: Blank Nancy , Straub Bernd F. , Opatz Till
Published: November 2011

The “exocyclic” 1,3‐benzyl shift observed in iminium salts derived from 1‐benzyl‐1,2,3,4‐tetrahydroisoquinolines is related to the “endocyclic” Knabe rearrangement. A crossover experiment, isotopic labelling, the study of initiators and inhibitors as well as DFT calculations of gas‐phase model structures provide evidence for a free‐radical pathway under kinetic entropy control that is not affected by “slow” radical traps.
Asymmetric Methoxyselenenylations with Chiral Selenium Electrophiles
Authors: Zhao Liwei , Li Zhong , Wirth Thomas
Published: November 2011

Very simple, chiral, non‐racemic diselenides were prepared and their corresponding selenium electrophiles were used for the stereoselective functionalization of alkenes. The influence of different alkenes on the outcome of the selenenylation reaction was investigated.
Chute channel dynamics in large, sand‐bed meandering rivers
Authors: Grenfell Michael , Aalto Rolf , Nicholas Andrew
Published: November 2011

Meander bends of many large, sand‐bed meandering rivers are partitioned by chute channels that convey permanent flow, and co‐exist with the mainstem for decades. As a first step toward understanding the dynamics and morphodynamic implications of these ‘bifurcate meander bends’, this study applied binary logistic regression analysis to determine whether it is possible to predict chute initiation based on attributes of meander bend character and dynamics. Regression models developed for the Strickland River, Papua New Guinea, the lower Paraguay River, Paraguay/Argentina, and the Beni River, Bolivia, revealed that the probability of chute initiation at a meander bend is a function of the bend extension rate (the rate at which a bend elongates in a direction perpendicular to the valley axis trend). Image analyses of all rivers and field observations from the Strickland suggest that the majority of chute channels form during scroll–slough development. Rapid extension is shown to favour chute initiation by breaking the continuity of point bar deposition and vegetation encroachment at the inner bank, resulting in widely‐spaced scrolls with intervening sloughs that are positively aligned with primary over‐bar flow. The rivers plot in order of increasing chute activity on an empirical meandering‐braided pattern continuum defined by potential specific stream power (ωpv) and bedload calibre (D50). Increasing stream power is considered to result in higher bend extension rates, with implications for chute initiation. In addition, chute stability is shown to depend on river sediment load relative to flow discharge (Qs/Q), such that while the Beni may plot in the region of highly braided rivers by virtue of a high potential specific stream power, the formation of stable chute channels is suppressed by the high sediment load. This tendency is consistent with previous experimental studies, and results in a planform that is transitional between single‐thread meandering and braided. Copyright © 2011 John Wiley & Sons, Ltd.
N‐cadherin and M‐cadherin are sequentially expressed in myoblast populations contributing to the first and second waves of myogenesis in the trout (Oncorhynchus mykiss)
Authors: Rescan Pierre‐Yves , Ralliere Cécile , Lebret Veronique
Published: November 2011

The objective of this study was to investigate the expression of two promyogenic cell surface adhesion receptors, N‐ and M‐cadherin, in developing trout (Oncorhynchus mykiss) somite, taking account of the recent identification of a dermomyotome‐like epithelium in teleosts. In situ hybridization showed that N‐cadherin was expressed throughout the paraxial mesoderm and nascent somite. As the somite matured, N‐cadherin expression disappeared ventrally from the sclerotome, and then mediolaterally from the differentiating slow and fast muscle cells of the embryonic myotome, to become finally restricted to the undifferentiated myogenic precursors forming the dermomyotome‐like epithelium that surrounds the embryonic myotome. By contrast, M‐cadherin, which was transcribed in the differentiating embryonic myotome, was never expressed in the dermomyotome‐like epithelium. In late‐stage trout embryos, M‐cadherin transcript was only detected at the periphery of the expanding myotome, where muscle cells stemming from the N‐cadherin positive dermomyotome‐like epithelium differentiate. Collectively, our results support the view that, in trout embryo, N‐cadherin is associated with muscle cell immaturity while M‐cadherin is associated with muscle cell maturation and differentiation and this during the two successive phases of myogenesis. J. Exp. Zool. (Mol. Dev. Evol.) 318:71–77,
2012. © 2011 Wiley Periodicals, Inc.
Induction of interferon‐λ contributes to toll‐like receptor 3‐mediated herpes simplex virus type 1 inhibition in astrocytes
Authors: Li Jieliang , Ye Li , Wang Xu , Hu Shuxian , Ho Wenzhe
Published: November 2011

Toll‐like receptor 3 (TLR3) recognizes double‐stranded RNA and induces type I interferon (IFN)‐mediated antiviral immunity against a number of viral infections. Type III IFN (IFN‐λ) is a newly identified antiviral cytokine that has biological functions similar to those of type I IFNs. We thus investigated the role of IFN‐λ in TLR3 activation‐mediated inhibition of herpes simplex virus type 1 (HSV‐1) in human primary astrocytes. Human astrocytes express endogenous IFN‐λ1 and IFN‐λ receptor complex, interleukin‐28 receptor α subunit (IL‐28Rα), and IL‐10Rβ. The activation of TLR3 by poly‐I:C treatment significantly induced the expression of IFN‐λ1 and IFN‐λ2/3 in astrocytes. The induction of IFN‐λ contributed to TLR3 activation‐mediated HSV‐1 inhibition in astrocytes. Investigation of the mechanisms showed that treatment of astrocytes with specific antibody against IFN‐λ receptor attenuated the anti‐HSV‐1 activity of poly‐I:C, indicating that endogenous IFN‐λ contributes to the anti‐HSV‐1 effect of TLR3 activation. The anti‐HSV‐1 effect of endogenous IFN‐λ was also confirmed by the finding that recombinant IFN‐λ treatment inhibited HSV‐1 infection of astrocytes. These results provide direct and compelling evidence that endogenous IFN‐λ participates in TLR3‐mediated antiviral activity, which may have important implications in host cell innate immunity against HSV‐1 infection in the CNS. © 2011 Wiley Periodicals, Inc.
Docosahexaenoic acid modulates inflammatory and antineurogenic functions of activated microglial cells
Authors: Antonietta Ajmone‐Cat Maria , Lavinia Salvatori Maria , De Simone Roberta , Mancini Melissa , Biagioni Stefano , Bernardo Antonietta , Cacci Emanuele , Minghetti Luisa
Published: November 2011

The complex process of microglial activation encompasses several functional activation states associated either with neurotoxic/antineurogenic or with neurotrophic/proneurogenic properties, depending mainly on the extent of activation and the nature of the activating stimuli. Several studies have demonstrated that acute exposure to the prototypical activating agent lipopolysaccharide (LPS) confers antineurogenic properties upon microglial cells. Acutely activated microglia ortheir conditioned media (CM) reduce neural stem progenitor cell (NPC) survival and prevent NPC differentiation into neurons. The present study tested the hypothesis that docosahexaenoic acid (DHA), a long‐chain polyunsatured fatty acid (L‐PUFA) with potent immunomodulatory properties, could dampen microglial proinflammatory functions and modulate their antineurogenic effect. We demonstrate that DHA dose dependently inhibits the synthesis of inflammatory products in activated microglia without inducing an alternative antiinflammatory phenotype. Among the possible DHA mechanisms of action, we propose the inhibition of p38 MAPK phosphorylation and the activation of the nuclear receptor peroxisome proliferator activated receptor (PPAR)‐γ. The attenuation of M1 proinflammatory phenotype has relevant consequences for the survival and differentiation of NPC, because DHA reverses the antineurogenic activities of conditioned media from LPS‐activated microglia. Our study identifies new relevant potentially protective and proneurogenic functions of DHA, exerted through the modulation of microglial functions, that could be exploited to sustain or promote neuroregenerative processes in damaged/aged brain. © 2011 Wiley Periodicals, Inc.