bluuebunny/crossref_metadata_2025 huggingface dataset:
Toxicity and metal bioaccumulation in Hordeum vulgare exposed to leached and nonleached copper amended soils
Authors: Schwertfeger D.M. , Hendershot W.H.
Published: April 2013

Soil leaching has been proposed as a way to reduce soil-spiking artifacts (i.e., increased acidity, metal solubility) that occur in soils amended with trace metal salts. Leaching metal-spiked samples prior to ecotoxicity testing is therefore expected to reduce toxicity; however, leaching not only removes excess amounts of the trace metal being tested, but also reduces the concentrations of cations that could decrease the toxic effects of the metal of interest. To clarify these conflicting processes, the effects of leaching on toxicity and bioaccumulation of Cu, Ca, and Al were investigated using 14-d plant assays conducted on leached and nonleached, Cu-spiked soils. The median effective concentration (EC50) to root elongation ranged from 78 µg/g to 589 µg/g. Leaching was found to reduce toxicity by 1.2-fold to 2.1-fold. The Cu2+ activity predicted toxicity better than root or shoot Cu concentrations, which were generally not affected by leaching. Plant uptake of Ca increased with increasing Cu dose in nonleached samples, which likely contributed to the hormesis-like response observed in these samples, whereas Ca uptake in the leached samples was more consistent with that of the control except at the largest Cu doses for which Ca uptake decreased. Surprisingly, Al uptake in the most acidic soil was greater in leached than nonleached samples, which may have contributed to the greater toxicity exhibited in this soil than was predicted by Cu2+ activity. These findings have implications for predicting trace metal toxicity in nutrient-stressed, acidic soils. Environ Toxicol Chem 2013;32:1800–1809. © 2013 SETAC
A new medium for Caenorhabditis elegans toxicology and nanotoxicology studies designed to better reflect natural soil solution conditions
Authors: Tyne William , Lofts Stephen , Spurgeon David J. , Jurkschat Kerstin , Svendsen Claus
Published: April 2013

A new toxicity test medium for Caenorhabditis elegans is presented. The test solution is designed to provide a better representation of natural soil pore water conditions than currently available test media. The medium has a composition that can readily be modified to allow for studies of the influences of a range of environmentally relevant parameters on nematode biology and toxicology. Tests conducted in the new medium confirmed that nematodes' reproduction was possible at a range of solution pH levels, offering the potential to conduct toxicity studies under a variety of conditions. A test to establish silver nanoparticle and dissolved silver nitrate toxicity, a study type not feasible in M9 or agar media due to precipitation and nanoparticle agglomeration, indicated lower silver nanoparticle (median effective concentration [EC50] of 6.5 mg Ag/L) than silver nitrate (EC50 0.28 mg Ag/L) toxicity. Characterization identified stable nanoparticle behavior in the new test medium. Environ Toxicol Chem 2013;32:1711–1717. © 2013 SETAC
Compressive sensing based multi‐user detection for machine‐to‐machine communication
Authors: Bockelmann C. , Schepker H. F. , Dekorsy A.
Published: April 2013

With the expected growth of machine‐to‐machine communication, new requirements for future communication systems have to be considered. More specifically, the sporadic nature of machine‐to‐machine communication, low data rates, small packets and a large number of nodes necessitate low overhead communication schemes that do not require extended control signaling for resource allocation and management. Assuming a star topology with a central aggregation node that processes all sensor information, one possibility to reduce control signaling is the estimation of sensor node activity.

In this paper, we discuss the application of greedy algorithms from the field of compressive sensing in a channel coded code division multiple access context to facilitate ajointdetection of sensor node activity and transmitted data. To this end, a short introduction to compressive sensing theory and algorithms will be given. The main focus, however, will be on implications of this new approach. Especially, we consider the activity detection, which strongly determines the performance of the overall system. We show that the performance on a system level is dominated by the missed detection rate in comparison with the false alarm rate. Furthermore, we will discuss the incorporation of activity‐aware channel coding into this setup to extend the physical layer detection capabilities tocode‐aidedjoint detection of data and activity. Copyright © 2013 John Wiley & Sons, Ltd.
Machine‐to‐machine communication with long‐term evolution with reduced device energy consumption
Authors: Tirronen Tuomas , Larmo Anna , Sachs Joachim , Lindoff Bengt , Wiberg Niclas
Published: April 2013

We present a method to reduce the device battery consumption to efficiently support battery‐operated machine‐to‐machine (M2M) communication in 3GPP long‐term evolution. The long‐term evolution discontinuous reception (DRX) is a key mechanism in reducing the device energy consumption, and we discuss how the traffic behaviour of machines in the Internet of things scenarios differs from the typical cellular user of today, for whom the current DRX mechanism is optimised for. We list typical transactions in M2M scenarios and discuss how the DRX operation is affected. We continue by introducing a power consumption model for M2M devices. Our assumption is that the device transmits small amounts of data in the uplink with deterministic intervals. The model takes into account the energy consumption in the active and the nonactive periods of the communication, which alternate depending on the DRX configuration. We use the model with different parameter settings referring to potential future M2M devices and identify the parameters, which contribute most to the device energy consumption. The results indicate that making the current maximum DRX cycle length longer will lead to significant gains in the energy consumption of M2M devices compared with what is possible today. Our key contributions include the discussion of the DRX mechanism in the Internet of things scenarios and the realistic assumptions for the potential of trading the responsiveness of a device for energy consumption gain with very long DRX cycles. Copyright © 2013 John Wiley & Sons, Ltd.
Infiltration and runoff generation processes in fire‐affected soils
Authors: Moody John A. , Ebel Brian A.
Published: April 2013

Post‐wildfire runoff was investigated by combining field measurements and modelling of infiltration into fire‐affected soils to predict time‐to‐start of runoff and peak runoff rate at the plot scale (1 m2). Time series of soil‐water content, rainfall and runoff were measured on a hillslope burned by the 2010 Fourmile Canyon Fire west of Boulder, Colorado during cyclonic and convective rainstorms in the spring and summer of 2011. Some of the field measurements and measured soil physical properties were used to calibrate a one‐dimensional post‐wildfire numerical model, which was then used as a ‘virtual instrument’ to provide estimates of the saturated hydraulic conductivity and high‐resolution (1 mm) estimates of the soil‐water profile and water fluxes within the unsaturated zone.

Field and model estimates of the wetting‐front depth indicated that post‐wildfire infiltration was on average confined to shallow depths less than 30 mm. Model estimates of the effective saturated hydraulic conductivity, Ks, near the soil surface ranged from 0.1 to 5.2 mm h−1. Because of the relatively small values of Ks, the time‐to‐start of runoff (measured from the start of rainfall),  tp, was found to depend only on the initial soil‐water saturation deficit (predicted by the model) and a measured characteristic of the rainfall profile (referred to as the average rainfall acceleration, equal to the initial rate of change in rainfall intensity). An analytical model was developed from the combined results and explained 92–97% of the variance of  tp, and the numerical infiltration model explained 74–91% of the variance of the peak runoff rates. These results are from one burned site, but they strongly suggest that  tp in fire‐affected soils (which often have low values of Ks) is probably controlled more by the storm profile and the initial soil‐water saturation deficit than by soil hydraulic properties. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.
Calretinin is essential for mesothelioma cell growth/survival in vitro: A potential new target for malignant mesothelioma therapy?
Authors: Blum Walter , Schwaller Beat
Published: April 2013

Malignant mesothelioma (MM) are highly aggressive asbestos‐related neoplasms, which show strong chemotherapy resistance, and there is no effective cure for MM so far. Calretinin (CR) is widely used as a diagnostic marker for epithelioid and mixed (biphasic) mesothelioma; however, little is known about CR's putative functions in tumorigenesis. CR protects against asbestos‐induced acute cytotoxicity mediated by the AKT/PI3K pathway, and furthermore, SV40 early region genes are able to upregulate CR in mesothelial cells. However, the precise role of CR in mesothelioma is still unknown. Downregulation of CR via lentiviral‐mediated short‐hairpin RNA significantly decreased the viability and proliferation of mesothelioma cells in vitro. The effect was strong in epithelioid‐dominated cell lines (ZL55 and MSTO‐211H). A weaker and delayed effect was observed in mesothelioma cells with prevalent sarcomatoid morphology (SPC111, SPC212 and ZL34). The specificity of the effect was confirmed by stable enhanced green fluorescent protein‐CR expression in mesothelioma cell lines and subsequent downregulation. Depletion of CR led these cancer cell lines to enter apoptosis within 72 hr postinfection via strong activation of the intrinsic caspase 9‐dependent pathway. Downregulation of CR in immortalized mesothelial cells LP9/TERT‐1 strongly blocked proliferation and caused a G1 block without decreasing viability or activating apoptosis pathways. These results demonstrate that downregulation of CR had a strong effect on the viability of MM cells and that CR is essential for cells derived from MM. The authors anticipate these findings to reveal CR as a highly interesting new putative therapeutic target for mesothelioma treatment of especially the epithelioid, as well as of the mixed and sarcomatoid type.
Changes in aberrant DNA methylation after Helicobacter pylori eradication: A long‐term follow‐up study
Authors: Shin Cheol Min , Kim Nayoung , Lee Hye Seung , Park Ji Hyun , Ahn Soyeon , Kang Gyeong Hoon , Kim Jung Mogg , Kim Joo Sung , Lee Dong Ho , Jung Hyun Chae
Published: April 2013

Changes of DNA methylation in gastric mucosae after eradication of Helicobacter pylori have not been clarified yet. From this background, we investigated time course of DNA methylation following H. pylori eradication in 221 successfully H. pylori eradicated subjects with endoscopic follow‐up at least for 6 months, including 114 controls, 53 subjects with gastric dysplasia and 54 patients with early gastric cancer. All dysplasia and gastric cancer patients underwent endoscopic resection at the time of enrollment. The methylation levels in LOX, APC and MOS genes from noncancerous gastric mucosae using quantitative methylation‐specific PCR, as well as the histologic findings of gastric mucosae, were compared before and after eradication. Average follow‐up duration was 26.0 months (range: 6 to 76 months). H. pylori eradication decreased methylation levels in LOX (p‐value for slope < 0.001) but not in APC. In MOS, decrease of its methylation level following H. pylori eradication was significant among controls without intestinal metaplasia (IM) (p‐value for slope < 0.05); however, it was not observed among patients with IM or those with dysplasia or gastric cancer. After H. pylori eradication, methylation level in MOS persistently increased in patients with dysplasia or gastric cancer (p < 0.01). In conclusion, H. pylori eradication decreases aberrant DNA methylation with gene‐specific manner. Methylation level in MOS is associated with IM and may be used as a surrogate marker for gastric cancer risk, regardless of H. pylori eradication history.
Utilization of genomic signatures to identify high‐efficacy candidate drugs for chemorefractory endometrial cancers
Authors: Kharma Budiman , Baba Tsukasa , Mandai Masaki , Matsumura Noriomi , Murphy Susan K. , Kang Hyun Sook , Yamanoi Koji , Hamanishi Junzo , Yamaguchi Ken , Yoshioka Yumiko , Konishi Ikuo
Published: April 2013

Endometrial cancer, one of the most common gynecologic malignancies, is increasing in Japan, nearly doubling over the last decade. High‐grade disease patients are often resistant to conventional chemotherapy with platinum agents; therefore, discovery of efficacious new drugs in this setting is required to benefit chemorefractory cases. The 50% growth‐inhibitory (GI50) concentration of 27 clinically relevant drugs was measured in the NCI60 panel of cell lines. Gene expression data were analyzed using Bayesian binary regression, to first generate a response signature for each drug and then to calculate individual susceptibility scores using in vivo endometrial cancer data (GSE2109; http://www.ncbi.nlm.nih.gov/geo) and in vitro data (GSE25458), as well as to identify candidate drugs for chemorefractory cases. Using these candidates, cell proliferation, apoptosis and caspase assays were performed in vitro. The tumor growth‐inhibitory effect of the candidate was also assessed in vivo using nude mice. Through microarray analysis, fludarabine and temsirolimus showed higher susceptibility scores in high‐grade cases compared to cisplatin, doxorubicin and paclitaxel. Fludarabine significantly inhibited cell proliferation and increased apoptosis in the cisplatin‐resistant endometrial cancer cell line, HEC1A, relative to HEC50B (p < 0.001). Fludarabine treatment also enhanced caspase‐3/7 activity in HEC1A relative to HEC50B cells (p < 0.001), and inhibited the growth of HEC1A xenograft tumors relative to cisplatin (p < 0.05). These results support that identification and use of genomic signatures can lead to identification of new therapeutic candidates that may prove beneficial to chemoresistant cases. Fludarabine may be useful in targeting high‐grade, chemorefractory endometrial cancer.
RESERVOIR DAILY INFLOW SIMULATION USING DATA FUSION METHOD
Authors: Ababaei Behnam , Mirzaei Farhad , Sohrabi Teymour , Araghinejad Shahab
Published: April 2013

Information about the parameters defining water resource availability is a key factor in its management which improves the operation policies for water resource systems. One of the most important parameters in this area is river streamflow. In this research, two different strategies of data fusion were tested for daily inflow simulation of the Taleghan Reservoir. Four artificial neural network models as well as two Hammerstein–Wiener models were used as individual simulation models. The results showed that the data fusion method has the capacity to improve substantially the results of individual simulation models. The individual models were also tested in combination with a weather generator model which was used to generate 100 yr of daily temperature and precipitation data. The results demonstrated that although some models performed well in calibration and validation phases, in combination with a weather generator they could result in eccentric outcomes. This research also showed that the data fusion method can combine the results of single simulation models to improve the final estimate and decrease the bandwidth of errors. Copyright © 2013 John Wiley & Sons, Ltd.
CORPORATE DIVIDEND POLICY DETERMINANTS: INTELLIGENT VERSUS A TRADITIONAL APPROACH
Authors: Longinidis Pantelis , Symeonidis Panagiotis
Published: April 2013

Dividend is the return that an investor receives when purchasing a company's shares. The decision to pay these dividends to shareholders concerns several other groups of people, such as financial managers, consulting firms, individual and institutional investors, government and monitoring authorities, and creditors, just to name a few. The prediction and modelling of this decision has received a significant amount of attention in the corporate finance literature. However, the methods used to study the aforementioned question are limited to the logistic regression method without any implementation of the advanced and expert methods of data mining. These methods have proven their superiority in other business‐related fields, such as marketing, production, accounting and auditing. In finance, bankruptcy prediction has the vast majority among data‐mining implementations, but to the best of the authors’ knowledge such an implementation does not exist in dividend payment prediction. This paper satisfies this gap in the literature and provides answers that help to understand the so‐called ‘dividend puzzle’. Specifically, this paper provides evidence supporting the hypothesis that data‐mining methods perform better in accuracy measures against the traditional methods used. The prediction of dividend policy determinants provides valuable benefits to all related parties, as they can manage, invest, consult and monitor the dividend policy in a more effective way. Copyright © 2013 John Wiley & Sons, Ltd.
Visualization of the post‐Golgi vesicle‐mediated transportation of TGF‐β receptor II by quasi‐TIRFM
Authors: Luo Wangxi , Xia Tie , Xu Li , Chen Ye‐Guang , Fang Xiaohong
Published: April 2013

Transforming growth factor β receptor II (Tβ RII) is synthesized in the cytoplasm and then transported to the plasma membrane of cells to fulfil its signalling duty. Here, we applied live‐cell fluorescence imaging techniques, in particular quasi‐total internal reflection fluorescence microscopy, to imaging fluorescent protein‐tagged Tβ RII and monitoring its secretion process. We observed punctuate‐like Tβ RII‐containing post‐Golgi vesicles formed in MCF7 cells. Single‐particle tracking showed that these vesicles travelled along the microtubules at an average speed of 0.51 μm/s. When stimulated by TGF‐β ligand, these receptor‐containing vesicles intended to move towards the plasma membrane. We also identified several factors that could inhibit the formation of such post‐Golgi vesicles. Although the inhibitory mechanisms still remain unknown, the observed characteristics of Tβ RII‐containing vesicles provide new information on intracellular Tβ RII transportation. It also renders Tβ RII a good model system for studying post‐Golgi vesicle‐trafficking and protein transportation. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synergistic cytotoxic effects of ions released by zinc–aluminum bronze and the metallic salts on osteoblastic cells
Authors: Grillo Claudia A. , Morales María L. , Mirífico María V. , Fernández Lorenzo de Mele Mónica A.
Published: April 2013

The use of copper‐based alloys for fixed dental crowns and bridges is increasingly widespread in several countries. The aim of this work is to study the dissolution of a zinc–aluminum–bronze and the cytotoxic effects of the ions released on UMR‐106 osteoblastic cell line. Two sources of ions were used: (1) ions released by the metal alloy immersed in the cell culture and (2) salts of the metal ions. Conventional electrochemical techniques, atomic absorption spectroscopy [to obtain the average concentration of ions (AC) in solution], and energy dispersive X‐ray (EDX) spectroscopy analysis were used to study the corrosion process. Corrosion tests revealed a strong influence of the composition of the electrolyte medium and the immersion time on the electrochemical response. The cytotoxicity was evaluated with (a) individual ions, (b) combinations of two ions, and (c) the mixture of all the ions released by a metal disc of the alloy. Importantly, synergistic cytotoxic effects were found when Al–Zn ion combinations were used at concentration levels lower than the cytotoxic threshold values of the individual ions. Cytotoxic effects in cells in the vicinity of the metal disc were also found. These results were interpreted considering synergistic effects and a diffusion controlled mechanism that yields to concentration levels, in the metal surroundings, several times higher than the measured AC value. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013.
Patterned CoCrMo and Al2O3 surfaces for reduced free wear debris in artificial joint arthroplasty
Authors: Tarabolsi Mohamad , Klassen Thomas , Mantwill Frank , Gärtner Frank , Siegel Frank , Schulz Arndt‐Peter
Published: April 2013

Surface wear of corresponding tribological pairings is still a major problem in the application of artificial joint surgery. This study aims at developing wear reduced surfaces to utilize them in total joint arthroplasty. Using a pico‐second laser, samples of medical CoCrMo metal alloy and Al2O3 ceramic were patterned by laser material removal. The subsequent tribological investigations employed a ring‐on‐disc method. The results showed that those samples with modified surfaces show less mass or volume loss than those with a regular, smooth surface. Using calf serum as lubricating medium, the volume loss of the structured CoCrMo samples was eight times lower than that of regular samples. By structuring Al2O3 surfaces, the wear volume could be reduced by 4.5 times. The results demonstrate that defined surface channels or pits enable the local sedimentation of wear debris. Thus, the amount of free debris could be reduced. Fewer abrasives in the lubricated so‐called three‐body‐wear between the contact surfaces should result in less surface damage. Apart from direct influences on the wear behavior, less amounts of free debris of artificial joints should also be beneficial for avoiding undesired reactions with the surrounding soft tissues. The results from this study are very promising. Future investigations should involve the use of simulators meeting the natural conditions in the joint and in vivo studies with living organisms. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A: 3447–3456, 2013.
Biological characterization of oxidized hyaluronic acid/resveratrol hydrogel for cartilage tissue engineering
Authors: Sheu Shiow‐Yunn , Chen Wen‐Shan , Sun Jui‐Sheng , Lin Feng‐Huei , Wu Tuoh
Published: April 2013

Osteoarthritis is a type of arthritis that is caused by breakdown of cartilage, with eventual loss of the cartilage of the joints. The ability of self‐repair in damaged cartilage tissue is limited; the aim of this work is to fabricate and characterize an oxidized hyaluronic acid/resveratrol (Oxi‐HA/Res) hydrogel for future applications in cartilage tissue engineering. Under physiological conditions, the Oxi‐HA/Res hydrogel was prepared by chemical crosslinking of Oxi‐HA with resveratrol solution and characterized by Fourier transform infrared spectrometry assay; the biocompatibility and gene expression of chondrocytes within the Oxi‐HA‐Res hydrogel then analyzed. The cell viability and cytotoxicity assays showed that the Oxi‐HA/Res hydrogel has good biocompatibility. Oxi‐HA/Res hydrogel can upregulate expression of type II collagen, aggrecan, and Sox‐9 genes; while down‐regulating IL‐1β, MMP‐1, MMP‐3, MMP13 gene expression. It can also reduce LPS‐induced inflammation and chondrocyte damage. The results of this study showed that the Oxi‐HA/Res hydrogel is biocompatible with chondrocytes, allows for extracellular matrix synthesis, and also reduce LPS‐induced inflammation and damage. These results suggest that Oxi‐HA/Res hydrogel may be a potential suitable cell carrier for chondrocyte cells in the treatment of cartilage defect. However, further in vivo study is mandatory for future possible clinical applications. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A: 3457–3466, 2013.
Astrocyte behavior and GFAP expression on Spirulina extract‐incorporated PCL nanofiber
Authors: Min Seul Ki , Kim Cho Rong , Jung Sang Myung , Shin Hwa Sung
Published: April 2013

Nanomaterials are attractive for use in biological systems due to their ability to control the microenvironment of cells. Additionally, nanofibers can mimic fibrous characteristics of natural tissues. This study was conducted to assess astrocyte activity and infiltration behavior on Spirulina extract‐embedded polycaprolactone (SP‐PCL) nanofiber. Astrocytes moved along with the nanofiber, and developed an elongated and stellate shape, which is similar to those in the natural neural tissue. In addition, the expression of GFAP, a biomarker representing the activation of astrocytes, was gradually up‐regulated with the increase of the concentration of Spirulina extract, indicating that Spirulina extract can control astrocyte activation. Overall, the results presented herein indicate that SP‐PCL nanofiber could be used in astrocyte tissue engineering for neuronal regeneration. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A: 3467–3473, 2013.
Creation of macropores in electrospun silk fibroin scaffolds using sacrificial PEO‐microparticles to enhance cellular infiltration
Authors: Wang Kai , Xu Meng , Zhu Meifeng , Su Hong , Wang Hongjun , Kong Deling , Wang Lianyong
Published: April 2013

Electrospun scaffolds are widely used in tissue engineering; however, a common problem is the poor cell infiltration because of the small pore size and tightly packed structure of these fibrous scaffolds. To address this issue, a novel technique was developed to fabricate electrospun silk fibroin (SF) scaffolds with rather macropores and high porosity using electrospraying‐generated PEO microparticles as porogen. The morphology and pore size of MPES scaffolds were evaluated by scanning electron microscopy. It was revealed that MPES scaffold had a relatively loose structure with an increase of mean pore size (i.e., approx. 30 μm of MPES vs. approx. 5 μm of traditional electrospun scaffolds (TES) and porosity (i.e., 95% vs. 84% of TES). Culture of mouse 3T3 fibroblast in TES and MPES scaffold revealed that both scaffolds could support cell attachment, spread and proliferation. Yet, cell inflitration in vitro under the static culture condition only occurred in the MPES scaffold. Subcutaneous implantation of scaffolds in rats further confirmed that the tissue ingrowth was more efficient in the MPES scaffold compared to TES scaffold. Thus, the use of PEO microparticles as porogen was a feasible and effective method for creating macroporous electrospun SF scaffold, which provided an alternative to address the limitation of cell infiltration associated with electrospun fibrous scaffold. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A: 3474–3481, 2013.
Chitosan–collagen scaffolds with nano/microfibrous architecture for skin tissue engineering
Authors: Sarkar Soumi Dey , Farrugia Brooke L. , Dargaville Tim R. , Dhara Santanu
Published: April 2013

In this study, a hierarchical nano/microfibrous chitosan/collagen scaffold that approximates structural and functional attributes of native extracellular matrix has been developed for applicability in skin tissue engineering. Scaffolds were produced by electrospinning of chitosan followed by imbibing of collagen solution, freeze‐drying, and subsequent cross‐linking of two polymers. Scanning electron microscopy showed formation of layered scaffolds with nano/microfibrous architechture. Physicochemical properties of scaffolds including tensile strength, swelling behavior, and biodegradability were found satisfactory for intended application. 3T3 fibroblasts and HaCaT keratinocytes showed good in vitro cellular response on scaffolds thereby indicating the matrices, cytocompatible nature. Scaffolds tested in an ex vivo human skin equivalent wound model, as a preliminary alternative to animal testing, showed keratinocyte migration and wound re‐epithelization—a prerequisite for healing and regeneration. Taken together, the herein proposed chitosan/collagen scaffold, shows good potential for skin tissue engineering. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A: 3482–3492, 2013.
An ice‐templated, linearly aligned chitosan‐alginate scaffold for neural tissue engineering
Authors: Francis Nicola L. , Hunger Philipp M. , Donius Amalie E. , Riblett Benjamin W. , Zavaliangos Antonios , Wegst Ulrike G. K. , Wheatley Margaret A.
Published: April 2013

Several strategies have been investigated to enhance axonal regeneration after spinal cord injury, however, the resulting growth can be random and disorganized. Bioengineered scaffolds provide a physical substrate for guidance of regenerating axons towards their targets, and can be produced by freeze casting. This technique involves the controlled directional solidification of an aqueous solution or suspension, resulting in a linearly aligned porous structure caused by ice templating. In this study, freeze casting was used to fabricate porous chitosan‐alginate (C/A) scaffolds with longitudinally oriented channels. Chick dorsal root ganglia explants adhered to and extended neurites through the scaffold in parallel alignment with the channel direction. Surface adsorption of a polycation and laminin promoted significantly longer neurite growth than the uncoated scaffold (poly‐L‐ornithine + Laminin = 793.2 ± 187.2 μm; poly‐L‐lysine + Laminin = 768.7 ± 241.2 μm; uncoated scaffold = 22.52 ± 50.14 μm) (P < 0.001). The elastic modulus of the hydrated scaffold was determined to be 5.08 ± 0.61 kPa, comparable to reported spinal cord values. The present data suggested that this C/A scaffold is a promising candidate for use as a nerve guidance scaffold, because of its ability to support neuronal attachment and the linearly aligned growth of DRG neurites. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A: 3493–3503, 2013.
Pikaia gracilens Walcott: Stem Chordate, or Already Specialized in the Cambrian?
Authors: MALLATT JON , HOLLAND NICHOLAS
Published: April 2013

For the past 35 years, the Cambrian fossil Pikaia gracilens was widely interpreted as a typical basal chordate based on short descriptions by Conway Morris. Recently, Conway Morris and Caron (CMC) (2012, Biol Rev 87:480–512) described Pikaia extensively, as a basis for new ideas about deuterostome evolution. This new Pikaia has characters with no clear homologues in other animals, so they could be phylogenetically uninformative autapomorphies. These characters include a dorsal organ, posterior ventral area, posterior fusiform structure, and anterior dorsal unit. Yet CMC interpret most of the unusual characters as primitive for chordates, thereby interpreting Pikaia as an even more convincing stem chordate than before. Moreover, they claim that segment (myomere) shape is a reliable guide for defining a chordate and even for assigning animals to their correct place in deuterostome phylogeny. By defining sigmoidal segments as a basal chordate character, they situate Pikaia at the base of the chordates and banish fossil yunnanozoans (which have straight segments) to a position deep within the deuterostomes. In addition, they consider amphioxus, with its conspicuously chevron‐shaped segments, to be so highly derived that it is of little use for reconstructing the first chordates. We question their overemphasis on the phylogenetic value of segment shape and their marginalizing of amphioxus. We deduce that Pikaia, not amphioxus, is specialized. We performed a cladistic analysis that showed the character interpretations of CMC are consistent with their wide‐ranging evolutionary scenario, but that these interpretations leave unresolved the position of Pikaia within chordates. J. Exp. Zool. (Mol. Dev. Evol.) 320B:247–271, 2013. © 2013 Wiley Periodicals, Inc.
One‐Pot Three‐Component Synthesis of Oxazine Derivatives in Water
Authors: Rostami‐Charati Faramarz , Hossaini Zinatossadat , Gharaee Ebrahim , Khalilzadeh Mohammad A.
Published: April 2013

A one‐pot synthesis of oxazine derivatives via reaction between activated acetylenic compounds, benzoyl cyanide, and N‐nucleophiles in water as the solvent is described‎.
Direct force measurement of single DNA–peptide interactions using atomic force microscopy
Authors: Chung Ji W. , Shin Dongjin , Kwak June M. , Seog Joonil
Published: April 2013

The selective interactions between DNA and miniature (39 residues) engineered peptide were directly measured at the single‐molecule level by using atomic force microscopy. This peptide (p007) contains an α‐helical recognition site similar to leucine zipper GCN4 and specifically recognizes the ATGAC sequence in the DNA with nanomolar affinity. The average rupture force was 42.1 pN, which is similar to the unbinding forces of the digoxigenin–antidigoxigenin complex, one of the strongest interactions in biological systems. The single linear fit of the rupture forces versus the logarithm of pulling rates showed a single energy barrier with a transition state located at 0.74 nm from the bound state. The smaller koff compared with that of other similar systems was presumably due to the increased stability of the helical structure by putative folding residues in p007. This strong sequence‐specific DNA–peptide interaction has a potential to be utilized to prepare well‐defined mechanically stable DNA–protein hybrid nanostructures. Copyright © 2013 John Wiley & Sons, Ltd.
Randomized codon mutagenesis reveals that the HIV Rev arginine‐rich motif is robust to substitutions and that double substitution of two critical residues alters specificity
Authors: Possik Elite J. , Bou Sleiman Maroun S. , Ghattas Ingrid R. , Smith Colin A.
Published: April 2013

The binding of the arginine‐rich motif (ARM) of HIV Rev protein to its high‐affinity site in stem IIB in the Rev response element (RRE) initiates assembly of a ribonucleoprotein complex that mediates the export of essential, incompletely spliced viral transcripts. Many biochemical, genetic, and structural studies of Rev–RRE IIB have been published, yet the roles of many peptide residues in Rev ARM are unconfirmed by mutagenesis. Rev aptamer I (RAI) is an optimized RRE IIB that binds Rev with higher affinity and for which mutational data are sparse. Randomized‐codon libraries of Rev ARM were assayed for their ability to bind RRE IIB and RAI using a bacterial reporter system based on bacteriophage λ N‐nut antitermination. Most Rev ARM residues tolerated substitutions without strong loss of binding to RRE IIB, and all except arginine 39 tolerated substitution without strong loss of binding to RAI. The pattern of critical Rev residues is not the same for RRE IIB and RAI, suggesting important differences between the interactions. The results support and aid the interpretation of existing structural models. Observed clinical variation is consistent with additional constraints on Rev mutation. By chance, we found double mutants of two highly critical residues, arginine 35 (to glycine) and asparagine 40 (to valine or lysine), that bind RRE IIB well, but not RAI. That an apparently distinct binding mode occurs with only two mutations highlights the ability of ARMs to evolve new recognition strategies and supports the application of neutral theories of evolution to protein–RNA recognition. Copyright © 2013 John Wiley & Sons, Ltd.
Magnetic resonance imaging of the wrist: Bone and cartilage injury
Authors: Hayter Catherine L. , Gold Stephanie L. , Potter Hollis G.
Published: April 2013

Magnetic resonance imaging (MRI) is particularly useful for imaging the wrist due to its superior soft tissue contrast and ability to detect subtle bone marrow changes and occult fractures. A high field (1.5T or greater) strength, dedicated wrist coil, and high in‐plane and through‐plane resolution must be utilized to successfully visualize the relatively thin cartilage of the wrist. MRI can be used to detect occult carpal bone fractures, identify complications following scaphoid fractures, and assess for avascular necrosis in the setting in Kienböck's and Preiser's disease. MRI is useful to identify secondary soft tissue and chondral pathology in impaction/impingement syndromes. The use of an intermediate‐echo time fast spin echo sequence allows for accurate assessment of articular cartilage, allowing evaluation of chondral wear in the setting of primary osteoarthritis and posttraumatic degenerative arthrosis. MRI is the most sensitive imaging modality for the detection of early inflammatory arthropathies and can detect synovitis, bone marrow edema, and early erosions in the setting of negative radiographs. J. Magn. Reson. Imaging 2013;37:1005–1019. © 2012 Wiley Periodicals, Inc.
Structural dynamics of 4‐pyrimidone in lower‐lying excited States
Authors: He Ben‐Feng , Zhao Yan‐Ying , Pei Ke‐Mei , Wang Hui‐Gang , Zheng Xu‐Ming
Published: April 2013

The structural dynamics of 4‐pyrimidone (4PMO) in the A‐ and B‐band absorptions was studied by using the resonance Raman spectroscopy combined with quantum chemical calculations to better understand whether the excited state intramolecular proton‐transfer (ESIPT) reaction occurs in Franck–Condon regions or not. The transition barrier for the ground state proton‐transfer tautomerization reaction between 3(H) (I) and hydroxy (II) was determined to be 165 kJ·mol−1 in vacuum on the basis of the B3LYP/6‐311++G(d,2p) level of theory calculations. Two ultraviolet absorption bands of 4PMO were, respectively, assigned as πH→π*L and πH→π*L+1 transitions. The vibrational assignments were done on the basis of the Fourier transform (FT)‐Raman and FT‐infrared (IR) measurements, the density‐functional theory computations and the normal mode analysis. The A‐ and B‐band resonance Raman spectra of 4PMO were measured in water, methanol and acetonitrile. The structural dynamics of 4PMO was obtained through the analysis of the resonance Raman intensity pattern. We discuss the similarities in the structural dynamics of 4PMO and 2‐thiopyrimidone (2TPM), and the results were used to correlate to the intramolecular hydrogen‐atom‐transfer process as observed by matrix‐isolation IR experiments for 4PMO. A variety of NH/CH bend modes + C = O stretch mode mark the hydrogen‐detachment‐attachment or ESIPT reaction initiated in Franck–Condon region for 4PMO and 2TPM. Copyright © 2013 John Wiley & Sons, Ltd.
Technical investigation of 15thand 19thcentury Chinese paper currencies: Fiber use and pigment identification
Authors: Shi Ji‐long , Li Tao
Published: April 2013

Herzberg staining, a quick and convenient tool for distinguishing non‐wood fibers from wood pulp, and Raman spectroscopy were employed to investigate three paper currencies issued under the reign of the Chinese Ming and Qing Emperors between 15thand 19thcenturies ‐da ming bao chao(AMS C‐14 Date: 1410‐1435 AD, ±1σ) from the Early Ming Dynasty (1405–1433 AD) andda qing bao chao(1859 AD) andhu bu guan piao(1854–1858 AD) from the Late Qing Dynasty (1840–1911 AD). Fiber staining and microscopic examination revealed a predominance of bast fiber from probably mulberry trees and very few cotton fibers (supposed to be environment contamination) inda ming bao chao; fibers inda qing bao chaoandhu bu guan piaoturned out to be quite pure, which are also bast fibers but very likely came from ramie and paper mulberry trees, respectively.

Raman analysis of red, blue, and black pigments on the investigated paper currencies showed that: (1) The reddish seal onda ming bao chaois not a vermilion (HgS) paste, as it is traditionally assumed, but instead a red lead (or minium, Pb3O4) one. The red pigments on bothda qing bao chaoandhu bu guan piaoare vermilion (HgS). (2) Prussian blue (Fe7(CN)18⋅14‐16H2O), a Western pigment, was identified as blue on bothda qing bao chaoandhu bu guan piao. (3) The black pigment on all these three paper currencies is amorphous carbon from soot. (4) Raman analysis of evenly distributed white pigment particles among the fibers inda qing bao chaoconfirmed the use of calcium carbonate (CaCO3) as coating pigment or fillers. Both microscopic examination of stained fibers and Raman analysis allowed, for the first time, the understanding of fiber and pigment use in producing ancient Chinese paper currencies. Copyright © 2013 John Wiley & Sons, Ltd.
Comparison of two ultrasound‐enhanced microextractions combined with HPLC for determining acaricides in water
Authors: Peng Bing , Yang Xiaoling , Zhang Jiaheng , Du Fengpei , Zhou Wenfeng , Gao Haixiang , Lu Runhua
Published: April 2013

An ultrasound‐enhanced in situ solvent formation microextraction has been developed first time and compared with ultrasound‐enhanced ionic‐liquid‐assisted dispersive liquid–liquid microextraction for the HPLC analysis of acaricides in environmental water samples. A ionic liquid ([C8MIM][PF6]) was used as the green extraction solvent through two pathways. The experimental parameters, such as the type and volume of both of the extraction solvent disperser solvent, ultrasonication time, and salt addition, were investigated and optimized. The analytical performance using the optimized conditions proved the feasibility of the developed methods for the quantitation of trace levels of acaricides by obtaining limits of detection that range from 0.54 to 3.68 μg/L. The in situ solvent formation microextraction method possesses more positive characteristics than the ionic‐liquid‐assisted dispersive liquid–liquid microextraction method (except for spirodiclofen determination) when comparing the validation parameters. Both methods were successfully applied to determining acaricides in real water samples.
Generation Y: An Agenda for Future Visitor Attraction Research
Authors: Leask Anna , Fyall Alan , Barron Paul
Published: April 2013

This study provides a comprehensive secondary‐based synthesis of previous studies on the profile and patterns of consumption of Generation Y, their consumption experiences and the role of information communication technologies and social media in determining their emerging patterns of behaviour at visitor attractions. The paper concludes by advancing a management‐oriented attraction research framework specific to Generation Y with a set of research propositions proposed to stimulate further research and management action on this specific and highly influential generational cohort. Copyright © 2013 John Wiley & Sons, Ltd.
Prospective study of voice outcomes and patient tolerance of in‐office percutaneous injection laryngoplasty
Authors: Birkent Hakan , Sardesai Maya , Hu Amanda , Merati Albert L.
Published: April 2013

Objectives/Hypothesis

In‐office percutaneous injection laryngoplasty is a common treatment for glottal insufficiency. Our objective was to prospectively study voice outcomes and patient tolerance of the procedure.

Study Design

Prospective case series.

Methods

Consecutive adult patients undergoing awake injection laryngoplasty were recruited. Voice Handicap Index (VHI)‐30; Consensus Auditory‐Perceptual Evaluation of Voice (CAPE‐V); and vocal Grade, Roughness, Breathiness, Asthenia and Strain (GRBAS) were evaluated prior to injection and 2 months postinjection. Visual analog scale (VAS) was completed by the patient before and after the procedure to quantify the amount of discomfort.

Results

Thirty‐five subjects enrolled; 26 (15 male, 11 female; mean age 61.6±13.2 years) had complete data. All components of VHI improved significantly: functional (P=0.0006), emotional (P=0.0004), physical (P=0.009), and total (P=0.0006). CAPE‐V also improved significantly (P=0.003). All components of GRBAS, except for roughness, improved significantly: grade (P=0.004), roughness (P=0.718), breathiness (P=0.023), asthenia (P=0.023), and strain (P=0.03). Patient expectations on the tolerance of the procedure was similar to what they reported immediately afterward (P=0.803).

Conclusions

Injection laryngoplasty is an effective method of treating glottal insufficiency, as measured by voice outcomes. Patients have realistic expectations on the procedure experience and find it tolerable. This is the first prospective study of injection laryngoplasty outcomes.

Level of Evidence

4. Laryngoscope, 2013
Significance of anterior commissure involvement in early glottic squamous cell carcinoma treated with trans‐oral CO2 laser microsurgery
Authors: Hakeem Arsheed H. , Tubachi Jagadish , Pradhan Sultan A.
Published: April 2013

Objectives/Hypothesis

To study and compare the outcome of trans‐oral CO2 laser microsurgery for early glottic squamous cell cancer with and without the involvement of anterior commissure (AC).

Study Design

This is a retrospective analysis of 296 cases of early glottic squamous cancer treated by trans‐oral CO2 laser microsurgery.

Methods

The patients were divided into two groups depending on whether AC was involved or not. The impact of AC involvement on rates of local recurrence, laryngeal preservation, overall survival, and disease‐specific survival was compared in both the groups.

Results

Out of the 296 cases, 61 cases had AC involvement, while in 235 cases AC was free of disease. Local recurrence rate was significantly higher at 29.51% in the group with AC involvement, while only 18.3% cases had local recurrence in the group without AC involvement with P value of 0.0001. On T stage‐wise analysis, 34.8% cases of T2 lesions with AC involvement developed local recurrence, as compared to only 10.26% cases of T2 without AC involvement with significant P value of 0.007. Larynx preservation rate was 95.8% versus 93.26% in the AC‐involved and AC not‐involved cases, respectively, without any statistical significance (P=0.287). The overall survival was 90.16% versus 86.38% in the cases with and without AC involvement, respectively, without significant P value 0.642.

Conclusions

Trans‐oral laser surgery is an excellent treatment option in patients with early glottic cancer irrespective of whether or not the AC is involved. Trans‐oral laser microsurgery for early glottic cancer involving AC requires adequate exposure, proper assessment, good experience, and advanced surgical skills.

Level of Evidence

4.Laryngoscope, 123:1912–1917, 2013
The prevalence and characteristics of tinnitus in the youth population of the United States
Authors: Mahboubi Hossein , Oliaei Sepehr , Kiumehr Saman , Dwabe Sami , Djalilian Hamid R.
Published: April 2013

Objectives/Hypothesis

To evaluate the prevalence, characteristics, and associated risk factors of tinnitus in U.S. adolescents.

Study Design

Cross‐sectional analyses of U.S. representative demographic and audiometric data, the National Health and Nutrition Examination Survey (NHANES) 2005 to 2008.

Methods

The study population consisted of 3,520 individuals aged 12 to 19 years with complete tinnitus‐related data. Tinnitus was defined as the presence of ringing or buzzing in the ears lasting for at least 5 minutes during the preceding 12 months. In addition, we defined a chronic tinnitus subgroup as being bothered by tinnitus for more than 3 months. Demographic and other data regarding tinnitus, smoking, body mass index (BMI), anemia, hypertension, history of ear infections, tympanostomy tube placement, otoscopy, tympanometry and hearing thresholds, history of firearm use, and recreational and occupational exposure to noise were extracted and analyzed.

Results

Overall, tinnitus lasting 5 minutes or more in the preceding 12 months was reported by 7.5% of the 12‐ to 19‐year‐old population. This represents about 2.5 million adolescents in the United States. The prevalence of chronic tinnitus was 4.7%, corresponding to about 1.6 million adolescents in the United States. Multivariable‐adjusted analysis revealed that both overall and chronic tinnitus were associated with female gender, low income, exposure to passive smoking, type A tympanogram, and occupational and recreational noise exposure. History of ≥3 ear infections and history of tympanostomy tube placement were associated only with overall tinnitus.

Conclusions

Tinnitus afflicts a substantial portion of the youth population. Further investigation of the association between tinnitus and the identified risk factors is warranted.

Level of Evidence

N/A. Laryngoscope, 123:2001–2008, 2013