bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation of amphoteric N,O‐carboxymethyl hydroxypropyl chitosan by a two‐step reaction
Authors: Chen Qiong , Han Xiaoxiao , Peng Shuhua , He Jianping , Deng Mingyu , Zhao Yongchao , Jiang Bo
Published: February 2014

A novel N,O‐carboxymethyl hydroxypropyl chitosan (HPCMS) derivative was prepared by a two‐step reaction. Water‐soluble hydroxypropyl chitosan (HPCS) with a degree of substitution of hydroxypropyl higher than 0.8 was first synthesized by the reaction of chitosan (CS) with propylene oxide (PO) with alkali as a catalyst. Then, amphoteric chitosan derivatives (HPCMS) with a degree of substitution of carboxymethyl ranging from 0.42 to 1.38 were prepared by the reaction of HPCS with chloroacetic acid in an aqueous solution with alkali as a catalyst. The structures of the polymers were characterized by Fourier transform infrared spectroscopy and NMR; this showed that the hydroxypropylation mainly occurred on the OH groups at the C‐6 of CS in the reaction of CS with PO. In the reaction of HPCS with chloroacetic acid, both the OH and NH2 groups of HPCS were susceptible to the carboxymethylation. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40460.
Synthesis and properties of a superabsorbent from an ultraviolet‐irradiated waste nameko mushroom substrate and poly(acrylic acid)
Authors: Zhang Mingyue , Cheng Zhiqiang , Liu Mengzhu , Zhang Yongqiang , Hu Meijuan , Li Junfeng
Published: February 2014

To better use the waste nameko mushroom substrate (WNMS) and prevent its pollution into the environment, a novel superabsorbent polymer was synthesized via the UV irradiation copolymerization of acrylic acid and WNMS in the presence of an initiator (dimethoxy‐2‐phenylacetophenone and ammonium persulfate) and crosslinker N,N′‐methylenebisacrylamide. The factors that had an influence on the water absorbency of the superabsorbent polymer were investigated and optimized. Under the optimized conditions, WNMS–poly(acrylic acid) was obtained. Its swelling behaviors, which followed the pseudo‐second‐order swelling kinetic model, were investigated in distilled water (1701 g/g) and a 0.9 wt % NaCl solution (388 g/g). The water absorbency was 1011 g/g in a 0.1 wt % urea solution and 80% amount of urea diffused into the gels. The urea diffusion followed a Fickian diffusion mechanism. Moreover, the product showed excellent water retention capabilities under the condition of high temperature or high pressure. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40471.
Thermally and magnetically dual‐responsive mesoporous silica nanospheres: preparation, characterization, and properties for the controlled release of sophoridine
Authors: Dong Liling , Peng Hailong , Wang Shenqi , Zhang Zhong , Li Jinhua , Ai Fanrong , Zhao Qiang , Luo Mei , Xiong Hua , Chen Lingxin
Published: February 2014

Novel thermally and magnetically dual‐responsive mesoporous silica nanoparticles [magnetic mesoporous silica nanospheres (M‐MSNs)–poly(N‐isopropyl acrylamide) (PNIPAAm)] were developed with magnetic iron oxide (Fe3O4) nanoparticles as the core, mesoporous silica nanoparticles as the sandwiched layer, and thermally responsive polymers (PNIPAAm) as the outer shell. M‐MSN–PNIPAAm was initially used to control the release of sophoridine. The characteristics of M‐MSN–PNIPAAm were investigated by transmission electron microscopy, Fourier transform infrared spectroscopy, X‐ray diffraction, thermogravimetry, N2 adsorption–desorption isotherms, and vibrating specimen magnetometry analyses. The results indicate that the Fe3O4 nanoparticles were incorporated into the M‐MSNs, and PNIPAAm was grafted onto the surface of the M‐MSNs via precipitation polymerization. The obtained M‐MSN–PNIPAAm possessed superparamagnetic characteristics with a high surface area (292.44 m2/g), large pore volume (0.246 mL/g), and large mesoporous pore size (2.18 nm). Sophoridine was used as a drug model to investigate the loading and release properties at different temperatures. The results demonstrate that the PNIPAAm layers on the surface of M‐MSN–PNIPAAm effectively regulated the uptake and release of sophoridine. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40477.
Etherification optimization for preparing partially hydrolized hydroxypropylated guar gum and its properties
Authors: Hongbo Tang , Yanping Li , Siqing Dong , Min Sun
Published: February 2014

The partially hydrolized hydroxypropylated guar gum (PHHGG) was prepared using GG as the raw material, hydrochloric acid as the hydrolysis agent, epoxy propane as the etherifying agent, ethanol as the solvent to obtain better property combination. The effect of the reaction temperature, reaction time, and amounts of sodium hydroxide, ethanol, and epoxy propane on the substitution degree of the partially hydrolized hydroxypropylated GG was investigated. These process parameters were optimized by the orthogonal test. Using polarized light microscopy, infrared spectrometer, differential scanning calorimetry, and thermogravimetric analyzer, the appearance, structure, and thermal property of the partially hydrolized hydroxypropylated GG (PHHGG) were observed and measured. The results indicated that the best process conditions for preparing the PHHGG were: reaction temperature = 60°C, reaction time = 12 h, amount of sodium hydroxide = 1.2%, amount of ethanol = 60%. The acid resistance and alkali resistance of GG were obviously improved by the acidolysis and hydroxypropylation. The particle appearance of GG was a thin strip after it was hydrolized by acid and hydroxypropylated by epoxy propane. The acidolysis increased the melting onset temperature, peak temperature, and end temperature of GG but the hydroxypropylation decreased them. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40489.
Preparation and characterization of a temperature‐sensitive nonwoven poly(propylene) with increased affinity for guest molecules
Authors: Amiri Setareh , Duroux Laurent , Nielsen Thorbjørn Terndrup , Larsen Kim Lambertsen
Published: February 2014

A temperature‐sensitive hydrogel with the capability of inclusion complex formation with guest molecules was successfully grafted onto the surface of nonwoven polypropylene (nonwoven PP). This was carried out by the use of N‐isopropylacrylamide monomer and a modified cyclodextrin (acrylamidomethyl‐β‐cyclodextrin (β‐CD‐NMA)). Fourier‐transform infra red (FT‐IR) and elemental analyses confirmed the presence of poly(N‐isopropylacrylamide) (PNIPAAm) and β‐CD‐NMA components on the surface of the textile. Equilibrium swelling ratio measurements showed that the grafted hydrogel maintained its temperature‐sensitive property compared to a nongrafted hydrogel. The effect of β‐CD‐NMA and crosslink agent concentrations on the grafting yield was studied. The β‐CD‐NMA content into the PNIPPAM‐ β‐CD‐NMA grafted nonwoven PP (PNIPAAm‐β‐CD‐NMA‐PP) was estimated by FT‐IR through a new procedure. The estimated amounts of β‐CD‐NMA in PNIPAAm‐β‐CD‐NMA‐PP were determined to be 0.9, 1.9 mg g−1 for 0.019M and 0.049M concentrations of β‐CD‐NMA in monomer solution, respectively. The PNIPAAm‐β‐CD‐NMA‐PP showed a remarkable increase in absorbance affinity of 8‐anilino‐1‐naphthalenesulfonic acid ammonium salt at 20°C from 0.93 to 3.33 µmol g−1 compared to PNIPAAm‐PP. Furthermore, the results showed a temperature‐sensitive loading affinity for PNIPAAm‐β‐CD‐NMA‐PP in absorbance of guest molecules due to the presence of β‐CD‐NMA. The use of hydrophobic guest molecules such as fragrance oils and antibiotics in modified fabrics can provide new applications in textile and pharmaceutical industry. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40497.
Elastic biodegradable starch/ethylene‐co‐vinyl alcohol fibre‐mesh scaffolds for tissue engineering applications
Authors: Susano Maria A. , Leonor Isabel B. , Reis Rui L. , Azevedo Helena S.
Published: February 2014

The fabrication of a biomaterial scaffold, with adequate physical and structural properties for tissue engineering applications, is reported. A blend of starch with ethylene‐vinyl alcohol (50/50 w/w, SEVA‐C) is used to produce 3D fibre‐mesh scaffolds by wet‐spinning. The scaffolds are characterized in terms of morphology, porosity, interconnectivity, and pore size, using scanning electron microscopy (SEM) and microcomputed tomography (μCT). The degradation behavior, as well as the mechanical properties of the scaffolds, is investigated in presence of alpha‐amylase enzyme at physiological concentration. Scaffolds with porosities ranging from 43 to 52%, interconnectivity of ∼70.5% and pore size between 118 and 159 μm, can be fabricated using the proposed methodology. The scaffolds exhibit an elastic behavior in the wet state with a compressive modulus of 7.96 ± 0.32 MPa. Degradation studies show that SEVA‐C scaffolds are susceptible to enzymatic degradation by alpha‐amylase, confirmed by the increase of weight loss (40% of weight loss after 12 weeks) and presence of degradation products (reducing sugars) in solution. The diameter of SEVA‐C scaffolds decreases with degradation time, increasing the overall porosity, interconnectivity and pore size. In vitro cell studies with human osteosarcoma cell line (SaOs‐2) showed a nontoxic and cytocompatible behavior of the developed fibre mesh scaffolds. The positive cellular response, together with structural and degradable properties, suggests that 3D SEVA‐C fibre‐meshes may be good candidates as tissue engineering scaffolds. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40504.
Properties of powdered associative alkali‐swellable acrylics thickeners synthesized by precipitation polymerization
Authors: Ma Xiaoyuan , Du Zhiping , Wang Wanxu , Li Ping , Li Qiuxiao , Zhao Yonghong , Li Enze
Published: February 2014

Powdered alkali‐swellable acrylics thickener (ASAT) was synthesized by precipitation polymerization with acrylic acid (AA) and stearyl acrylate (SA) as monomer, allyl sucrose ether (ASE) as crosslink agent and lauroyl peroxide (LPO) as initiator in the solvent of ethyl acetate. The powders were normal distribution in the range 1–80 μm and showed sensitive to pH in water. Before pH 7, both of the viscosity and the light transmittance of the APAT emulsion increased with enhancing pH value. ASE and SA played an important role in the properties of ASAT. When the amount of ASE was increased, the crosslink degree in the ASAT molecule increased. As the result, the viscosity of its emulsion increased firstly and then decreased, but the light transmittance of the emulsion decreased monotonously. Introduction of SA led to formation of an associative ASAT. Therefore, both of the viscosity and light transmittance of ASAT emulsion increased firstly and then decrease with increasing the amount of SA. Meanwhile, the associative ASAT emulsion showed shear thinning behavior, good salt tolerate, and less sensitivity to temperature. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40512.
A comparative study on the effects of material blending method on the physico‐mechanical properties of WPCs made from MDF dust
Authors: Chavooshi Arash , Madhoushi Mehrab , Shakeri Alireza , Khazaeian Abolghasem
Published: February 2014

The present study was carried out to investigate the effect of material‐blending method and filler content on the physical and mechanical properties of medium density fiberboard (MDF) dust/PP composites. In the sample tests preparation, 40, 50, and 60 wt % of MDF dust were used as lignocellulosic material. Test samples were made to measure the influence of material‐blending method and MDF dust content on water absorption (WA), thickness swelling (TS), modulus of elasticity (MOE), modulus of rupture (MOR), tensile strength, tensile modulus, and withdrawal strengths of fasteners. The mechanical properties of the test panels significantly decreased with increasing MDF dust contents due to the reduction of interface bond between the fiber and polymer matrix. The WA and TS values also increased by increasing the amount of MDF dust. So with the increase in the MDF dust content, there are more water residence (high hydroxyl groups (OH) of cellulose and hemicelluloses) sites, thus more water is absorbed, so it can reduce mechanical strength. Furthermore, the results indicated that the physical and mechanical properties of samples made with melt‐blend method were more acceptable than those of dry‐blend method. Field emission scanning electron microscopy micrographs also showed that the polymer and the filler phase mixed better in the melt‐blend method. On the basis of the findings of this research, it appears evident that certain amount of MDF dust material with suitable material‐blending method can be used in manufacturing of wood–plastic composites for providing good physical and mechanical properties. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40513.
Whole‐community facilitation by beaver: ecosystem engineer increases waterbird diversity
Authors: Nummi Petri , Holopainen Sari
Published: February 2014

Wetlands are rich in biodiversity, but globally threatened. After a long period of regional extirpation, beavers have recently returned to many European areas and are now restoring wetlands. The beaver is remarkable regarding the large impacts it has not only on individual species but on entire communities and ecosystems. In fact, beavers are referred to as ‘ecosystem engineers’.

The facilitative effect of the beaver Castor canadensis on a waterbird community of seven species of waders and ducks in boreal ponds was studied by using the before–after control–impact method (BACI) and analysing the effect of the duration of flooding. The before–after setting could be used since beavers had caused disturbance by flooding several forest ponds during the course of this long‐term study (1988–2009). The study took place in southern Finland, where waterbirds were surveyed four times during the breeding season.

The number of waterbird species per pond per year was significantly higher during beaver inundation than before beaver activity, as was the waterbird abundance per survey. Changes were negligible in the controls. The numbers of all seven species increased during flooding, although the increase was significant in only three species. Common teal Anas crecca and green sandpiper Tringa ochropus showed the most positive numerical response to flooding. Mallard Anas platyrhynchos and wigeon Anas penelope were new species entering the duck guild in the flooded wetlands. The beneficial effect of the flood lasted the whole period of inundation, although the most substantial increase in species number appeared during the first two years of flooding.

The beaver acted as a whole‐community facilitator for waterbirds. It was inferred from previous studies that this was done by modifying the habitat to make it more productive and structurally favourable. It is concluded that favouring beavers is a worthwhile tool in restoring wetlands to promote waterbird communities.

Copyright © 2014 John Wiley & Sons, Ltd.
Low‐Dimensional Carboxylate‐Bridged GdIII Complexes for Magnetic Refrigeration
Authors: Liu Sui‐Jun , Xie Chen‐Chao , Jia Ji‐Min , Zhao Jiong‐Peng , Han Song‐De , Cui Yu , Li Yue , Bu Xian‐He
Published: February 2014

Four carboxylate‐bridged GdIII complexes (1–4) with 1D/2D structures have been synthesized by using the hydrothermal reaction of Gd2O3 with various carboxylate ligands. Compounds 1 and 2 contained the same [2n] GdIIIOH ladders, but with different crystallographically independent GdIII ions, whilst the structures of compounds 3 and 4 were composed of [Gd4(μ3‐OH)2(piv)8(H2O)2]2+ units and 1D ladder GdIII chains, respectively. Antiferromagnetic interactions occurred in compounds 1–3, owing to their small GdOGd angles, whereas ferromagnetic coupling occurred in compound 4, in which the GdOGd angles were larger. These complexes exhibited a distinct magnetocaloric effect (MCE), which was affected by their different magnetic densities and exchange interactions. Among these compounds, complex 4 presented the largest MCE (−ΔSmmax=43.6 J kg−1 K−1), the lowest Mw/NGd ratio (the highest magnetic density), and weak ferromagnetic coupling. Therefore, a lower Mw/NGd ratio and weaker exchange interactions (a smaller absolute value of θ) between GdIII ions resulted in a larger MCE for the GdIII complexes.
Exploring the Role of Neural Mirroring in Children with Autism Spectrum Disorder
Authors: Ruysschaert Lieselot , Warreyn Petra , Wiersema Jan R. , Oostra Ann , Roeyers Herbert
Published: February 2014

Investigating the underlying neural mechanisms of autism spectrum disorder (ASD) has recently been influenced by the discovery of mirror neurons. These neurons, active during both observation and execution of actions, are thought to play a crucial role in imitation and other social‐communicative skills that are often impaired in ASD. In the current electroencephalographic study, we investigated mu suppression, indicating neural mirroring in children with ASD between the ages of 24 and 48 months and age‐matched typically developing children, during observation of goal‐directed actions and non‐goal‐directed mimicked hand movements, as well as during action execution. Results revealed no significant group differences with significant central mu suppression in the ASD children and control children during both execution and observation of goal‐directed actions and during observation of hand movements. Furthermore, no significant correlations between mu suppression on one hand and quality of imitation, age, and social communication questionnaire scores on the other hand were found. These findings challenge the “broken mirror” hypothesis of ASD, suggesting that impaired neural mirroring is not a distinctive feature of ASD. Autism Res 2014, 7: 197– 206. © 2014 International Society for Autism Research, Wiley Periodicals, Inc.
Exploring the feasibility of using electronic health records in the surveillance of fetal alcohol syndrome
Authors: Hansen Craig , Adams Marvin , Fox Deborah J. , O'Leary Leslie A. , Frías Jaime L. , Freiman Heather , Meaney F. John
Published: February 2014

BACKGROUND

Explore the use of electronic health records (EHRs) in fetal alcohol syndrome (FAS) surveillance systems.

METHODS

Using EHRs we identified diagnoses and anthropometric measurements related to the FAS criteria developed by the Fetal Alcohol Syndrome Surveillance Network (FASSNet) among children aged 0 to 12 years.

RESULTS

There were 143,393 distinct children aged between 0 and 12 years enrolled in Kaiser Permanente, Georgia, during the study period. Based on diagnoses and anthropometric measurements, 20,101 children met at least one criterion of interest, and when grouped into combinations of different criteria there were 2285 who met GROWTH+CNS criteria, 76 children who met GROWTH+FACE criteria, 107 children who met CNS+FACE criteria, and 93 children who met GROWTH+CNS+FACE criteria. The prevalence of FAS as defined by FASSNet is 1.92 per 1000 children. We linked 17,084 (85.0%) children to their mothers in the health plan; only 3% of mothers of children in the GROWTH+CNS+FACE group had an indication of alcohol or drugs use, but they had the highest rate of depression (39%).

CONCLUSION

Data of utility in identification of FAS are readily available in EHRs and may serve as a basis for intervention with at‐risk children and in planning of future FAS surveillance programs. Birth Defects Research (Part A) 100:67–78, 2014. © 2014 Wiley Periodicals, Inc.
Mortality in babies with achondroplasia: Revisited
Authors: Simmons Kristen , Hashmi S. Shahrukh , Scheuerle Angela , Canfield Mark , Hecht Jacqueline T.
Published: February 2014

BACKGROUND: Natural history studies performed 30 years ago identifying higher mortality among children born with achondroplasia, a genetic dwarfing condition, resulted in clinical recommendations aimed at improving mortality in childhood. The objective of this study was to determine if mortality rates have changed over the past few decades. METHODS: Children born with achondroplasia during 1996 to 2003 were ascertained from the Texas Birth Defects Registry and matched with death certificate data from the Bureau of Vital Statistics through 2007. Infant and overall mortality rates, both crude and standardized to the 2005 (SMR2005) and 1975 (SMR1975) U.S. populations, were calculated. RESULTS: 106 children born with achondroplasia were identified. Four deaths were reported, with all occurring in the first year of life (mortality rate: 41.4 /1000 live‐births). Infant mortality was higher when standardized to the 2005 U.S. population (SMR2005:6.02, 95% CI:1.64–15.42) than the 1975 population (SMR1975:2.58, 95% CI:0.70–6.61). CONCLUSION: The higher SMR2005 compared with SMR1975, along with the fact that SMR1975 was nearly half that of a previous cohort reported 25 years ago (rate ratio: 0.53, 95% CI: 0.11–2.25), reflect a discrepancy in the changes in mortality in the overall population and in our cohort. Although an overall improvement in mortality, especially after the first year of life, is observed in our cohort, children with achondroplasia are still at a much higher risk of death compared with the general population. A longer follow‐up is needed to elucidate whether evaluation/intervention changes have resulted in significant improvement in long‐term survival among these patients. Birth Defects Research (Part A) 100:247–249, 2014. © 2014 Wiley Periodicals, Inc.
Key Learnings from Performance of the U.S. EPA Endocrine Disruptor Screening Program (EDSP) Tier 1 In Vitro Assays
Authors: LeBaron Matthew J. , Coady Katie K. , O'Connor John C. , Nabb Diane L. , Markell Lauren K. , Snajdr Suzanne , Sue Marty M.
Published: February 2014

Tier 1 of the U.S. EPA Endocrine Disruptor Screening Program comprises 11 studies: five in vitro assays, four in vivo mammalian assays, and two in vivo nonmammalian assays. The battery is designed to detect compounds with the potential to interact with the estrogen, androgen, or thyroid signaling pathways. This article examines the procedures, results, and data interpretation for the five Tier 1 in vitro assays: estrogen receptor (ER) and androgen receptor binding assays, an ER transactivation assay, an aromatase assay, and a steroidogenesis assay. Data are presented from two laboratories that have evaluated approximately 11 compounds in the Tier 1 in vitro assays. Generally, the ER and androgen receptor binding assays and the aromatase assay showed good specificity and reproducibility. As described in the guideline for the ER transactivation assay, a result is considered positive when the test compound induces a reporter gene signal that reaches 10% of the response seen with 1 nM 17β‐estradiol (positive control). In the experience of these laboratories, this cutoff criterion may result in false‐positive responses. For the steroidogenesis assay, there is variability in the basal and stimulated production of testosterone and estradiol by the H295R cells. This variability in responsiveness, coupled with potential cell stress at high concentrations of test compound, may make it difficult to discern whether hormone alterations are specific steroidogenesis alterations (i.e., endocrine active). Lastly, both laboratories had difficulty meeting some recommended performance criteria for each Tier 1 in vitro assay. Data with only minor deviations were deemed valid.
Opening the genetic toolbox of niche model organisms with high throughput techniques: Novel proteins in regeneration as a case study
Authors: Looso Mario
Published: February 2014

Understanding in vivo regeneration of complex structures offers a fascinating perspective for translation into medical applications. Unfortunately, mammals in general lack large‐scale regenerative capacity, whereas planarians, newts or Hydra can regenerate complete body parts. Such organisms are, however, poorly annotated because of the lack of sequence information. This leads to limited access for molecular biological investigations. In the last decade, high throughput technologies and new methods enabling the effective generation of transgenic animals have rapidly evolved. These developments have allowed the extensive use of niche model organisms as part of a trend towards the accessibility of a greater panel of model species for scientific research. The case study that follows provides an insight into the impact of high throughput techniques on the landscape of models of regeneration. The cases presented here give evidence of alternative stem cell maintenance pathways, the identification of new protein families and new stem cell markers.
Wie sich Mensch und Nahrung beeinflussen
Authors: Höffeler Fritz
Published: February 2014

Zwischen Menschen und ihrer Nahrung bestehen zahlreiche Wechselwirkungen und Abhängigkeiten, die sich besonders in Veränderungen der genetischen Ausstattungen und in Modifikationen der Genregulationen widerspiegeln. Vier Interaktionswege konnten identifiziert werden: Das individuelle Genrepertoire des Menschen beeinflusst die Reaktionen seines Körpers auf die zugeführte Nahrung (Nutrigenetik); Nahrungsbestandteile beeinflussen die Regulation einer Vielzahl der Gene (Nutrigenomik); traditionelle Ernährungsgewohnheiten können zu wechselseitigen genetischen Veränderungen der Menschen und seiner Nahrungsorganismen führen (Coevolution); auf Grund der positiven Selektion erwünschter und der negativen Selektion unerwünschter Eigenschaften verändert der Mensch das Genrepertoire nahezu aller seiner Nahrungsorganismen (Züchtung und Kultivierung).
Neues vom Pferde‐Stammbaum
Authors: Kronberg Inge
Published: February 2014

Die Vorfahren unserer heutigen Pferde sind durch zahlreiche Fossilfunde dokumentiert: Ausgehend von kleinen vierzehigen Waldtieren hin zu großen einzehigen Steppentieren erscheinen sie als Lehrbuchbeispiel für eine evolutive Reihe. Jeder neue Fossilfund fügte jedoch weitere Zweige hinzu. Der Pferde‐Stammbaum gleicht eher einem Busch, in dem viele Linien ausgestorben sind und nur die Gattung Equus, also Zebra, Halbesel, Esel und echtes Pferd, bis heute erhalten blieb. Eine vergleichende Genomanalyse von Pferdeknochen‐DNA aus dem Permafrostboden Kanadas hat jetzt gezeigt, dass die Abspaltung der Equus‐Linie deutlich älter ist als bisher vermutet.
Proteinen durch Immunpräzipitation auf der Spur
Authors: Hauk Andrea
Published: February 2014

Will man ein bestimmtes Protein in einem komplexen Gemisch aus Proteinen anreichern, so bietet sich die Immunpräzipitation als Methode der Wahl an. Hier können Antigene im kleinen Maßstab mit Hilfe von spezifischen Antikörpern ausgefällt werden. In der Forschung ist diese Methode beliebt, um beispielsweise die Aktivität von Proteinen, mögliche Modifikationen oder auch Komplexbildungen zu untersuchen.
Characterization of NO‐producing neurons in the rat corpus callosum
Authors: Barbaresi Paolo , Fabri Mara , Mensà Emanuela
Published: February 2014

Introduction

The aim of this study was to determine the presence and distribution of nitric oxide (NO)‐producing neurons in the rat corpus callosum (cc).

Material and methods

To investigate this aspect of cc organization we used nicotinamide adenine dinucleotide phosphate diaphorase (NADPH‐d) histochemistry and neuronal NO synthase (nNOS) immunocytochemistry.

Results

Intense NADPH‐d‐positive (NADPH‐d+) neurons were found along the rostrocaudal extension of the cc (sagittal sections). They were more numerous in the lateral cc and gradually decreased in the more medial regions, where they were very few or absent. The Golgi‐like appearance of NADPH‐d+ intracallosal neurons allowed dividing them into five morphological types: (1) bipolar; (2) fusiform; (3) round; (4) polygonal; and (5) pyramidal. The number of NADPH‐d+ neurons (both hemispheres) was counted in two brains using 50‐μm thick sections. In the first brain, counts involved 145 sections and neurons were 2959; in the second, 2227 neurons were counted in 130 sections. The distribution and morphology of nNOS‐immunopositive (nNOSIP) neurons was identical to that of NADPH‐d+neurons. Some of these neurons were observed in the cc ependymal region, where they might be in contact with cerebrospinal fluid (CSF), monitoring its composition, pH, and osmolality changes, or playing a role in regulating the synthesis and release of several peptides. The somatic, dendritic, and axonal processes of many NADPH‐d+/nNOSIP neurons were closely associated with intracallosal blood vessels.

Conclusions

Such close relationship raises the possibility that these neurons are a major source of NO during neural activity. As NO is a potent vasodilator, these findings strongly suggest that NO‐positive neurons transduce neuronal signals into vascular responses in selected cc regions, thus giving rise to hemodynamic changes detectable by neuroimaging.
BOLD signal and functional connectivity associated with loving kindness meditation
Authors: Garrison Kathleen A. , Scheinost Dustin , Constable R. Todd , Brewer Judson A.
Published: February 2014

Loving kindness is a form of meditation involving directed well‐wishing, typically supported by the silent repetition of phrases such as “may all beings be happy,” to foster a feeling of selfless love. Here we used functional magnetic resonance imaging to assess the neural substrate of loving kindness meditation in experienced meditators and novices. We first assessed group differences in blood oxygen level‐dependent (BOLD) signal during loving kindness meditation. We next used a relatively novel approach, the intrinsic connectivity distribution of functional connectivity, to identify regions that differ in intrinsic connectivity between groups, and then used a data‐driven approach to seed‐based connectivity analysis to identify which connections differ between groups. Our findings suggest group differences in brain regions involved in self‐related processing and mind wandering, emotional processing, inner speech, and memory. Meditators showed overall reduced BOLD signal and intrinsic connectivity during loving kindness as compared to novices, more specifically in the posterior cingulate cortex/precuneus (PCC/PCu), a finding that is consistent with our prior work and other recent neuroimaging studies of meditation. Furthermore, meditators showed greater functional connectivity during loving kindness between the PCC/PCu and the left inferior frontal gyrus, whereas novices showed greater functional connectivity during loving kindness between the PCC/PCu and other cortical midline regions of the default mode network, the bilateral posterior insula lobe, and the bilateral parahippocampus/hippocampus. These novel findings suggest that loving kindness meditation involves a present‐centered, selfless focus for meditators as compared to novices.
Reducing anxiety and enhancing physical performance by using an advanced version of EMDR: a pilot study
Authors: Rathschlag Marco , Memmert Daniel
Published: February 2014

Background

The main aim of this pilot study was to investigate an advanced version of eye movement desensitization and reprocessing (EMDR) for reducing anxiety.

Methods

Fifty participants were asked at two times of measurement (T1 and T2 with a rest of 4 weeks) to generate anxiety via the recall of autobiographical memories according to their anxiety. Furthermore, the participants were randomly assigned to an experimental group and a control group, and the experimental group received an intervention of 1–2 h with the advanced version of EMDR in order to their anxiety 2 weeks after T1. At T1 as well as T2, we measured the intensity of participants' anxiety with a Likert scale (LS) and collected participants' state (temporary) and trait (chronic) anxiety with the State‐Trait Anxiety Inventory (STAI). In addition, we measured participants' physical performance in a test for the finger musculature under the induction of their anxiety.

Results

The results showed that participant's ratings of their perceived intensity of anxiety (measured by a 9‐point LS) and the state and trait anxiety decreased significantly in the experimental group but not in the control group from T1 to T2. Moreover, the physical performance under the induction of participants' anxiety increased significantly in the experimental group from T1 to T2 and there were no significant changes in the control group.

Conclusions

The study could show that the advanced version of EMDR is an appropriate method to reduce anxiety.
The anatomy of the aging aorta
Authors: Collins Jarrod A. , Munoz Julie‐Vanessa , Patel Toral R. , Loukas Marios , Tubbs R. Shane
Published: February 2014

Age‐associated changes to aortic anatomy and physiology have an effect on hemodynamics and play a large role in the genesis of cardiovascular pathologies including atherosclerosis, congestive heart failure, and aortic aneurysm. Despite their recognized role in hemodynamics, the complete mechanism for aortic aging is still not clear and their full effects on cardiovascular pathologies are unknown. This article serves as a review of the normal anatomy of the human aorta and its known age‐associated changes. Clin. Anat. 27:463–466, 2014. © 2014 Wiley Periodicals, Inc.
Cryptic collagen IV promotes cell migration and adhesion in myeloid leukemia
Authors: Favreau Amanda J. , Vary Calvin P. H. , Brooks Peter C. , Sathyanarayana Pradeep
Published: February 2014

Previously, we showed that discoidin domain receptor 1 (DDR1), a class of collagen‐activated receptor tyrosine kinase (RTK) was highly upregulated on bone marrow (BM)‐derived CD33+ leukemic blasts of acute myeloid leukemia (AML) patients. Herein as DDR1 is a class of collagen‐activated RTK, we attempt to understand the role of native and remodeled collagen IV in BM microenvironment and its functional significance in leukemic cells. Exposure to denatured collagen IV significantly increased the migration and adhesion of K562 cells, which also resulted in increased activation of DDR1 and AKT. Further, levels of MMP9 were increased in conditioned media (CM) of denatured collagen IV exposed cells. Mass spectrometric liquid chromatography/tandem mass spectrometry QSTAR proteomic analysis revealed exclusive presence of Secretogranin 3 and InaD‐like protein in the denatured collagen IV CM. Importantly, BM samples of AML patients exhibited increased levels of remodeled collagen IV compared to native as analyzed via anti‐HUIV26 antibody. Taken together, for the first time, we demonstrate that remodeled collagen IV is a potent activator of DDR1 and AKT that also modulates both migration and adhesion of myeloid leukemia cells. Additionally, high levels of the HUIV26 cryptic collagen IV epitope are expressed in BM of AML patients. Further understanding of this phenomenon may lead to the development of therapeutic agents that directly modulate the BM microenvironment and attenuate leukemogenesis.
Enzymatic Synthesis of Tertiary Alcohols
Authors: Müller Michael
Published: February 2014

Tertiary alcohols are found as a motif in many pharmaceuticals and natural products. Elucidation of their biosynthesis is thus a good starting point for the identification of enzymes for the synthesis of chiral tertiary alcohols. To date, however, relatively few enzymatic methods for such syntheses have been established in biotechnological processes. Whereas secondary alcohols can be efficiently synthesized via the (asymmetric) reduction of ketones, a generally applicable method for the enzymatic synthesis of tertiary alcohols has been more difficult to identify. Herein, a survey of the biocatalytic methods for the synthesis of (chiral) tertiary alcohols is presented. Advantages and disadvantages of the respective methods are discussed from a synthetic point of view.
Enhancement of RANKL‐induced MITF‐E expression and osteoclastogenesis by TGF‐β
Authors: Asai Kumiko , Funaba Masayuki , Murakami Masaru
Published: February 2014

Microphthalmia‐associated transcription factor (MITF) is a transcription factor that is expressed in limited types of cells, including osteoclasts, but the expression and role of MITF during osteoclastogenesis have not been fully elucidated. The expression of the MITF‐E isoform but not that of the MITF‐A isoform was induced in response to differentiation stimulation towards osteoclasts by receptor activator of NF‐κB ligand (RANKL) in both RAW264.7 cells and primary bone marrow cells. The RANKL‐induced formation of tartrate‐resistant acid phosphatase (TRAP)‐positive multinucleated cells was inhibited in RAW264.7 cells expressing siRNA for MITF‐E. Transforming growth factor‐β (TGF‐β) enhanced RANKL‐induced MITF‐E expression and ‐TRAP positive multinucleated cell formation. In particular, TGF‐β potentiated the formation of larger osteoclasts. The expression levels of NFATc1, TRAP and CtsK, genes related to osteoclast development and activity, were concurrently enhanced by TGF‐β in the presence of RANKL. Furthermore, the expression of dendritic cell‐specific transmembrane protein (DC‐STAMP), Itgav, Itga2, Itga5, Itgb1, Itgb3 and Itgb5, genes related to cell adhesion and fusion, were up‐regulated by co‐treatment with TGF‐β. In particular, the regulatory expression of Itgav and Itgb5 in response to RANKL with or without TGF‐β resembled that of MITF‐E. Because MITF is involved in cell fusion in some cell systems, these results imply a role for MITF‐E as an enhancer of osteoclastogenesis and that RANKL‐induced levels of both MITF‐E mRNA and of MITF‐dependent gene expression are enhanced by treatment with TGF‐β. Copyright © 2014 John Wiley & Sons, Ltd.
Retinoic acid induces mouse bone marrow‐derived CD15+, Oct4+ and CXCR4+ stem cells into male germ‐like cells in a two‐dimensional cell culture system
Authors: Kashani Iraj Ragerdi , Zarnani Amir Hassan , Soleimani Masoud , Abdolvahabi Mir Abbas , Nayernia Karim , Shirazi Reza
Published: February 2014

We have examined the effect of retinoic acid (RA) on differentiation of bone marrow‐derived CD15+, Oct4+ and CXCR4+ cells into male germ cells. Bone marrow stem cells (BMSCs) were isolated from the femur of 3–4‐week‐old male C57BL/6 mice. Magnetic‐activated cell sorting (MACS) system was used to sort CD15+, Oct4+ and CXCR4+ cells. RT‐PCR was used to follow the expression of pluripotency markers. Sorted CD15+, Oct4+ and CXCR4+ cells were cultured in an undifferentiated condition on a feeder layer of mitomycin C‐inactivated C2C12. The embryoid‐like bodies were differentiated into male germ cells by retinoic acid. To identify the expression of male germ specific markers, differentiated cells were analysed by means of reverse transcriptase polymerase chain reaction (RT‐PCR) and immunofluorescence staining. RT‐PCR and immunofluorescence show that bone marrow‐derived CD15+, Oct4+ and CXCR4+ cells express pluripotency markers, Oct4, Nanog, Rex‐1, SOX‐2 and AP. The purified CD15+, Oct4+ and CXCR4+ formed structures like embryoid bodies when plated over a feeder layer; these bodies were alkaline phosphatase positive. When cells were induced by RA, bone marrow‐derived CD15+, Oct4+ and CXCR4+ were positive for Mvh, Dazl, Piwil2, Dppa3 and Stra8, that known molecular markers of male germ cells. Thus RA can induce differentiation of mouse bone marrow‐derived CD15+, Oct4+ and CXCR4+ cells into male germ cells in vitro. Negative results for the gene expression analysis of female germ cells markers, GDF9 and ZP3, confirmed this conclusion.
Stent fracture: Insights on mechanisms, treatments, and outcomes from the food and drug administration manufacturer and user facility device experience database
Authors: Mamas Mamas A. , Foin Nicolas , Abunassar Chad , Khan Muhammad A. , Di Mario Carlo , Fraser Douglas G.
Published: February 2014

Objectives

Stent fracture (SF) is an uncommon complication following percutaneous coronary intervention. Previous studies of SF have either been small single‐center studies or have reported data mainly from first generation platforms. The FDA MAUDE database was used to identify cases of SF to gain mechanistic insight into procedural and anatomical factors predisposing to this complication, to define treatment and associated clinical outcomes in contemporary and first generation stent platforms.

Methods and Results

Using defined search terms, 376 unique reports of SF were identified in the FDA MAUDE database of which 336 (89.4%) occurred in first generation stent platforms with 96.1% occurring in the Cypher platform. The remaining 40 reports (10.6%) occurred with a similar distribution of cases across different contemporary platforms. Common vessel characteristics associated with SF included calcification, tortuosity, stent overlap, and significant angulation with the most common modality of presentation being in‐stent restenosis or stent thrombosis.

Conclusions

SF occurs most commonly in first generation Cypher stents with a similar distribution of cases across different contemporary platforms. Optimal treatment strategy remains unclear with the decision to treat and the modality of treatment utilized depending on the type and severity of SF © 2014 Wiley Periodicals, Inc.
Major thrombocytopenia after balloon‐expandable transcatheter aortic valve replacement: Prognostic implications and comparison to surgical aortic valve replacement
Authors: Jilaihawi Hasan , Doctor Niraj , Chakravarty Tarun , Kashif Mohammad , Mirocha James , Cheng Wen , Lill Michael , Nakamura Mamoo , Gheorghiu Mitch , Makkar Raj R.
Published: February 2014

Objectives

We sought to investigate the magnitude and clinical importance of thrombocytopenia post transcatheter aortic valve replacement (TAVR).

Background

Thrombocytopenia has been observed after TAVR but has not been well studied.

Methods

Major thrombocytopenia (platelet count <100 × 109/L) was studied following aortic valve interventions in a single center. Changes in platelets were compared in 246 patients undergoing balloon‐expandable TAVR and a similar population of 57 cases undergoing surgical aortic valve replacement (SAVR in the US PARTNER IA trial).

Results

An early drop in platelets was seen on the day of intervention. The drop day 1 post procedure was similar but slightly greater with SAVR vs. TAVR. In both platelet counts continued to drop, reaching a nadir of approximately 50–60% of the baseline platelet count at day 2–3, starting to recover after day 5. Early major thrombocytopenia occurred post TAVR in 37% of patients but was not significantly related to major bleeding (OR 0.89, 95% CI 0.51–1.60, P = 0.69) or risk of stroke (HR 0.61, 95% CI 0.16–2.20, P = 0.45); there was a trend to greater acute kidney injury (OR 1.76, 95% CI 0.95–3.26, P = 0.073) and mortality (HR 1.47, 95% CI 0.98–2.22, P = 0.065). Major thrombocytopenia was persistent in 7.7% of patients and this was independently associated with mortality (HR 3.65, 95% CI 1.63–8.16, P = 0.002).

Conclusions

Post‐TAVR thrombocytopenia is a common phenomenon and its magnitude appears similar to that seen after SAVR. It is most often transient, not associated with adverse sequelae and, unless persistent, should be managed in an expectant fashion. © 2014 Wiley Periodicals, Inc.
Immediate and short‐term outcomes after percutaneous atrial septal defect closure using the new nit‐occlud ASD‐R device
Authors: Peirone Alejandro , Contreras Alejandro , Ferrero Adolfo , da Costa Rodrigo Nieckel , Pedra Simone Fontes , Pedra Carlos A.C.
Published: February 2014

Objectives

To evaluate the feasibility, safety, and efficacy of implantation of the new Nit Occlud ASD‐R® (NOASD‐R) device for percutaneous closure of ostium secundum atrial septal defects (ASD‐OS).

Background

Device catheter implantation has become the method of choice for most patients with ASD‐OS. No single device has proven to be ideal for this type of procedure. The NOASD‐R has a distinct design that may help to overcome limitations of other devices.

Methods

A prospective, single arm, observational study including all consecutive patients receiving the NOASD‐R device for ASD‐OS closure between October 2011 and September 2013 was performed. Patient selection, device design, deployment technique, complications, and procedural outcomes were evaluated.

Results

Seventy‐four patients underwent attempted transcatheter ASD‐OS closure using the NOASD‐R device. Implantation of the occluder was successful in 73 patients (98.6%). The majority of patients were female (79.5%) with a median age of 17.2 years (range: 2–74). A 2‐D transthoracic color‐Doppler echocardiogram (TTE) obtained at the 3 or 6 month follow‐up visit showed complete occlusion of the ASD‐OS in 72/73 patients (98.6%). At a mean follow‐up interval of 11.4 ± 6.8 months there have been no episodes of late device embolization, cardiac perforation or erosion, endocarditis, thromboembolism, wire fracture, embolic neurologic events, or death.

Conclusions

We report the first worldwide clinical experience using the NOASD‐R device for ASD‐OS closure. The procedure was feasible, with a high rate of successful implantations, and safe. High ASD‐OS closure rates and no complications were encountered during short‐term follow‐up. © 2014 Wiley Periodicals, Inc.
What is the cause of the opthalmoplegia in this young child? What treatment is necessary?
Authors: Kassam Karim , Visavadia Bhavin
Published: February 2014

Key Clinical Message

Not all orbital fractures are associated with clinical signs of swelling, ecchymosis, and subconjunctival hemorrhage. The “white‐eyed” blowout fracture is more commonly seen in children and is associated with entrapment of the extraocular muscles. Early surgical intervention is indicated and it must have been in the differential diagnosis of the head injury patient with opthalmoplegia.
Nickel–Gallium Intermetallic Nanocrystal Catalysts in the Semihydrogenation of Phenylacetylene
Authors: Li Changming , Chen Yudi , Zhang Shitong , Zhou Junyao , Wang Fei , He Shan , Wei Min , Evans David G. , Duan Xue
Published: February 2014

The chemoselective hydrogenation of alkyne is of great importance in the chemical industry, in which intermetallic compounds (IMCs) have attracted extensive interest as efficient catalysts. Herein, we demonstrate the preparation of several supported Ni–Ga IMCs (Ni3Ga, Ni5Ga3, and NiGa) via a facile in situ reduction of layered double hydroxide (LDH) precursors, which demonstrate significantly improved catalytic activity and selectivity for the selective hydrogenation of phenylacetylene to styrene. The composition and particle size of Ni–Ga IMCs can be tuned by adjusting the Ni/Ga ratio or reduction temperature during the topotactic transformation process of LDHs, and the best catalytic behavior can be obtained over the Ni3Ga IMC with a styrene yield of 87.7 % (particle size=7.2 nm at 40 °C and 0.3 MPa), which is better than that of most of the reported Ni catalysts. The X‐ray absorption fine‐structure characterization and DFT calculations reveal the electron transfer from Ga to Ni and active‐site isolation by Ga in Ni–Ga IMCs, which account for the excellent hydrogenation selectivity. The significantly improved catalytic performance makes Ni–Ga IMC catalysts promising candidates for the selective hydrogenation of alkyne.