bluuebunny/crossref_metadata_2025 huggingface dataset:
Nanotextured substrates with immobilized aptamers for cancer cell isolation and cytology
Authors: Wan Yuan , Mahmood M. Arif Iftakher , Li Na , Allen Peter B. , Kim Young‐tae , Bachoo Robert , Ellington Andrew D. , Iqbal Samir M.
Published: July 2011

BACKGROUND:

The detection of a small number of circulating tumor cells (CTCs) is important, especially in the early stages of cancer. Small numbers of CTCs are hard to detect, because very few approaches are sensitive enough to differentiate these from the pool of other cells. Improving the affinity of a selective, surface‐functionalized molecule is important given the scarcity of CTCs in vivo. There are several proteins and aptamers that provide such high affinity; however, using surface nanotexturing increases this affinity even further.

METHODS:

The authors report an approach to improve the affinity of tumor cell capture by using novel aptamers against cell membrane overexpressed epidermal growth factor receptors (EGFRs) on a nanotextured polydimethylsiloxane (PDMS) substrate. Surface‐immobilized aptamers were used to specifically capture tumor cells from physiologic samples.

RESULTS:

The nanotexturing of PDMS increased surface roughness at the nanoscale. This increased the effective surface area and resulted in a significantly higher degree of surface functionalization. The phenomenon resulted in increased density of immobilized EGFR‐specific RNA aptamer molecules and provided significantly higher efficiency to capture cancer cells from a mixture. The data indicated that CTCs could be captured and enriched, leading to higher yield yet higher background.

CONCLUSIONS:

A comparison between glass slides, plain PDMS, and nanotextured PDMS functionalized with aptamers demonstrated that a 2‐fold approach of using aptamers on nanotextured PDMS can be important for cancer cytology devices, and especially for the idea of a “lab‐on‐chip,” toward higher yield in capture efficiency. Cancer 2012;. © 2011 American Cancer Society.
Phase 2 trial of oxaliplatin and pemetrexed as an induction regimen in locally advanced head and neck cancer
Authors: Gilbert Jill , Murphy Barbara , Dietrich Mary S. , Henry Eve , Jordan Richard , Counsell Ashley , Wirth Pamela , Yarbrough Wendell G. , Slebos Robert J. , Chung Christine H.
Published: July 2011

BACKGROUND:

This phase 2 trial evaluated the tolerability and clinical efficacy of the combination of oxaliplatin and pemetrexed as an induction chemotherapy regimen in locally advanced head and neck squamous cell carcinoma (HNSCC).

METHODS:

Forty‐two patients were enrolled in the study. Patients received pemetrexed 300 mg/m2 intravenously (IV) and oxaliplatin 85 mg/m2 IV every 14 days for a total of 4 cycles. A subset of patients consented to correlative studies including tumor tissue for human papillomavirus (HPV) detection and expression of DNA repair genes that may be predictive of response or resistance to oxaliplatin or pemetrexed.

RESULTS:

Response data were available for 40 patients. Eighteen had a partial response, and 1 had a complete response, for a response rate of 47.5%. Patients with HPV+ disease demonstrated superior response rates, progression‐free survival, and overall survival. The regimen was well tolerated, with predominantly grade 1 or 2 alanine aminotransferase/aspartate aminotransferase elevation. One patient had grade 5 toxicity with neutropenia and sepsis. The authors did not identify genes predictive of response or toxicity, although HPV+ tumors demonstrated a unique gene expression signature.

CONCLUSIONS:

Although the response rate of oxaliplatin and pemetrexed proved less than anticipated, the combination remains an active induction regimen in HNSCC. This regimen should be evaluated further in combination with targeted agents, such as cetuximab, especially in the HPV+ patient population. Cancer 2012;. © 2011 American Cancer Society.
Single brain metastasis: whole‐brain irradiation plus either radiosurgery or neurosurgical resection
Authors: Rades Dirk , Veninga Theo , Hornung Dagmar , Wittkugel Oliver , Schild Steven E. , Gliemroth Jan
Published: July 2011

BACKGROUND:

The current study was conducted to compare neurosurgical resection (NR) followed by whole‐brain irradiation (WBI) (NR + WBI) with WBI followed by radiosurgery (WBI + RS) in patients with a single brain metastasis.

METHODS:

The outcome of 41 patients treated with WBI + RS was retrospectively compared with 111 patients who received NR ;+ WBI with respect to local control of the treated metastasis and survival. Eleven additional potential prognostic factors were investigated, including WBI schedule, patient age, patient gender, Karnofsky performance score (KPS), primary tumor type, extracerebral metastases, recursive partitioning analysis (RPA) class, interval between the first diagnosis of cancer to the treatment of brain metastasis, metastatic site, maximum diameter of the metastasis, and graded prognostic assessment (GPA) score.

RESULTS:

The 1‐year local control rates were 87% after WBI + RS and 56% after NR + WBI (P = .001). Using the Cox proportional hazards model, the treatment regimen remained significant (risk ratio [RR], 2.46; 95% confidence interval [95% CI], 1.29‐5.17 [P = .005]). On the multivariate analysis, local control was also found to be associated with the maximum diameter of the metastasis. The 1‐year survival rates were 61% after WBI + RS and 53% after NR + WBI (P = .16). Acute and late toxicities were similar in both groups. On the multivariate analysis, KPS, extracerebral metastases, RPA class, and the GPA score were found to be independent predictors of survival.

CONCLUSIONS:

The use of WBI + RS resulted in significantly better local control of the treated metastasis than NR + WBI. Survival was not found to be significantly different in either group. Because WBI + RS is less invasive than NR + WBI, it appears to be preferable for many patients with a single brain metastasis. These results should be confirmed in a randomized trial. Cancer 2012;. © 2011 American Cancer Society.
Structure‐controlled growth of ZnO nanonails by thermal evaporation technique
Authors: Senthil Kumar M. , Chhikara D. , Srivatsa K. M. K.
Published: July 2011

Wurtzite ZnO nanonail structures have been grown on sapphire substrate by simple thermal evaporation of Zn powder in oxygen ambient. Growth parameters such as growth temperature and oxygen gas flow have been examined for the growth of nanonail structure. It is found that the nanonail structures repeatedly grow under a certain relation between the growth temperature and the oxygen flow. Also, at higher growth temperature, the nanonails grow in the form of branched‐structures. The grown ZnO nanonails have hexagonally well‐faceted cap and grow mostly perpendicular to the sapphire substrate. Excellent luminescence properties of a strong UV emission peak with negligible green band have been obtained at room temperature. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis, transformation to octahedron‐like crystals, and gas‐sensing property of six‐horned nanospheres of Cu2O
Authors: Wang Xiaoqing , Liu Zhipeng , Qian Yitai
Published: July 2011

Single‐crystal six‐horned nanospheres of Cu2O with a diameter of 760 nm in average were prepared in aqueous solution of CuCl2and NaOH by using ascorbic acid as the reductant in the presence of sodium dodecyl benzenesulfonate (SDBS) at room temperature. The horn grows along the <100> direction, which is consistent with the protuberant direction of an apex of octahedron. The formation process of six‐horned nanospheres included two steps: the formation of Cu2O nanospheres via Ostwald ripening process, and the appearance of horns on the surface of nanospheres under low concentration of SDBS. As increasing the concentration of SDBS, the six‐horned nanospheres could be transformed into octahedron‐like Cu2O. And at the same concentration of SDBS, keeping the volume ratio of water and ethanol in mixed solutions as 1:1, Cu2O octahedra were obtained. Moreover, gas‐sensing property showed that six‐horned nanospheres of Cu2O had higher sensitivity compared with Cu2O nanospheres and Cu2O octahedra to ethanol gas (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Remarkable Impact of Water on the Discharge Performance of a Silicon–Air Battery
Authors: Cohn Gil , Macdonald Digby D. , Ein‐Eli Yair
Published: July 2011

Here, we report on a Si–air/ionic liquid electrolyte battery whose performance improves with small amounts of water in the electrolyte. The shift of the generation zone of the SiO2 discharge product from the air cathode surface into the bulk region of the liquid electrolyte, caused by water addition, is demonstrated through various means. Addition of 15 vol % water leads to an increase of 40 % in the discharge capacity as compared to the capacity obtained using a pure ionic liquid electrolyte. If the water content increases above 20 vol %, the Si–air cell capacity dramatically decreases. The water–ionic liquid electrolyte mixture shows a maximum in the ionic conductivity with a water content of 10 vol %. In‐depth studies indicate a reduced amount of discharge product at the air electrode using 15 vol % H2O electrolyte. The morphology of the anode surface, as well as the developed surface film in the presence of water‐containing ionic liquid, is reported. This study shows that exposing a Si–air battery to a humid environment does not result in capacity losses, but rather improves cell performance.
Cutting the vagus nerve below the diaphragm prevents maternal potentiation of infant rat vocalization
Authors: Shair Harry N. , Smith Jonathan A. , Welch Martha G.
Published: July 2011

In maternal potentiation, the rate of vocalization by a young organism during isolation is greatly enhanced if that isolation has been immediately preceded by an interaction with the mother (or other adult female in the case of rats). The enhancement in isolation‐induced vocalization rate does not occur if the young animal had an interaction with other social companions like littermates or with familiar inanimate stimuli like home cage shavings. The present study demonstrates that pups whose vagus nerve is cut below the diaphragm do not potentiate vocalization after an interaction with their dam. The vocalization rates of denervated pups in a first isolation, in the presence of the dam, and during cold exposure do not differ from control pups. Their non‐vocal behaviors also appear unaffected by the surgery. Similar to what has been shown in studies of fever‐induced behavioral changes, an intact vagus nerve from the gut is necessary for young rat pups to show normal social mediation of their isolation‐induced vocal responses. © 2011 Wiley Periodicals, Inc. Dev Psychobiol 54:70–76, 2012.
The social environment during pregnancy and lactation shapes the behavioral and hormonal profile of male offspring in wild cavies
Authors: Siegeler Katja , Sachser Norbert , Kaiser Sylvia
Published: July 2011

In mammals, the development of individual behavioral profiles can be influenced considerably by social factors during early phases of life. In guinea pigs, for instance, sons whose mothers experienced social instability during pregnancy and lactation show an infantilized behavioral profile. Here, we examined whether the same phenomenon exists also in wild cavies, the ancestor of the domestic guinea pig. Using a comparable experimental approach, our results revealed a similar behavioral infantilization as well as a delayed gonadal development of sons when their mothers had lived under unstable social conditions. These data show clearly that the behavioral and hormonal profile of male wild cavies can be shaped significantly by the social environment in which their mothers lived during pregnancy and lactation. Hence the underlying mechanisms cannot have been brought about by artificial selection during domestication. Rather, they represent maternal effects evolved through natural selection adjusting the offspring to the current environmental conditions. © 2011 Wiley Periodicals, Inc. Dev Psychobiol 53:575–584, 2011.
Integrins and the extracellular matrix: Key mediators of development and regeneration of the sensory nervous system
Authors: Gardiner Natalie J.
Published: July 2011

The somatosensory nervous system is responsible for the transmission of a multitude of sensory information from specialized receptors in the periphery to the central nervous system. Sensory afferents can potentially be damaged at several sites: in the peripheral nerve; the dorsal root; or the dorsal columns of the spinal cord; and the success of regeneration depends on the site of injury. The regeneration of peripheral nerve branches following injury is relatively successful compared to central branches. This is largely attributed to the presence of neurotrophic factors and a Schwann cell basement membrane rich in permissive extracellular matrix (ECM) components which promote axonal regeneration in the peripheral nerve. Modulation of the ECM environment and/or neuronal integrins may enhance regenerative potential of sensory neurons following peripheral or central nerve injury or disease. This review describes the interactions between integrins and ECM molecules (particularly the growth supportive ligands, laminin, and fibronectin; and the growth inhibitory chondroitin sulfate proteoglycans (CSPGs)) during development and regeneration of sensory neurons following physical injury or neuropathy. © 2011 Wiley Periodicals, Inc. Develop Neurobiol 71: 1054‐1072, 2011
Inrush current simulation of two‐winding power transformer using machine parameters estimated by winding structure design procedure
Authors: Tokunaga Yoshitaka , Kubota Kunihiro
Published: July 2011

This paper presents a technique for estimation of machine parameters of a two‐winding power transformer using a winding structure design procedure. In particular, it is very difficult to obtain machine parameters for transformers in customers' facilities. Using the estimation technique, the machine parameters can be calculated from only the nameplate data of these transformers. Subsequently, EMTP‐ATP simulation of the inrush current was carried out using the machine parameters estimated by the techniques developed in this study, and the simulation results were found to reproduce the measured waveforms. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 177(2): 1–9, 2011; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.20994
A trial implementation of a distance estimation method based on standing waves of audible sound
Authors: Ohmata Norimitsu , Uebo Tetsuji , Nakasako Noboru , Shinohara Toshihiro
Published: July 2011

In many engineering fields, the distance to target is very important information. In a typical method, the distance is estimated by measuring the time delay between transmitted and reflected waves. However, it is difficult to estimate short distances with a method like this. In the field of microwave radar, a method using standing waves to measure short distances and multiple targets is known. We have applied this method to distance estimation using audible sound and have shown the validity of this method by our simulations and experiments. In this paper, we present a prototype system for distance estimation in which this method is implemented, and evaluate the performance of this system by experiments in an actual sound field. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 177(2): 41–48, 2011; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.21160
Studies on thrust characteristics of high‐thrust spiral motor
Authors: Kominami Tsutomu , Fujimoto Yasutaka
Published: July 2011

Linear actuators are used in various industrial applications. Conventional linear actuators are a combination of a rotational motor and a ball screw, a hydraulic actuator, or a linear motor. However, these actuators have some demerits. This paper proposes a spiral motor (SPRM) that comprises a helical stator and a helical mover. Owing to its helical structure, the SPRM can be expected to show better performance compared to the conventional linear actuator. A stator and a mover are shown in Figs. 1 and 2, respectively. Helical motion is obtained by this motor and only linear motion is extracted by canceling rotational motion at the end effector. There are two types of SPRMs. One has no ball screw on the output axis, while the other has a ball screw. The former can be used in a direct drive system. However, the gap between the stator and the mover should be controlled because the motor is a magnetic levitation system without a ball screw. Further, the motor requires two three‐phase inverters. The other motor is easy to control because it does not require gap control. However, the motor is inferior to the first motor with regard to position control since the friction in this motor is larger. In this study, a prototype of the SPRM is developed. The prototype constructed is a motor with a ball screw. In this motor, the stator and mover are made of block cells. The stator block is shown in Fig. 3 and the mover block is shown in Fig. 4. The prototype of the SPRM shown in Fig. 5, is developed by using these two blocks. An experiment is conducted to examine the driving of the SPRM. The experimental result is shown in Fig. 6. From this result, it is evident that comprising a helical stator and a helical mover can generate linear motion. Another experiment is conducted for measuring the thrust characteristic of the motor. The result obtained is shown in Fig. 7. From the figure, the thrust constant of the spiral motor, Kf, is obtained as 538.0 N/A. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 177(2): 58–64, 2011; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.21168
Functionalization of tactile sensation for robot based on haptograph and model decomposition
Authors: Yokokura Yuki , Katsura Seiichiro , Ohishi Kiyoshi
Published: July 2011

In the real world, robots should be able to recognize the environment in order to be of help to humans. A video camera and a laser range finder are devices that can help robots recognize the environment. However, these devices cannot obtain tactile information from environments. Future human‐assisting robots should have the ability to recognize haptic signals, and a disturbance observer can possibly be used to provide the robot with this ability. In this study, a disturbance observer is employed in a mobile robot to functionalize the tactile sensation. This paper proposes a method that involves the use of the haptograph and modal decomposition for the haptic recognition of road environments. The haptograph presents a graphic view of the tactile information. It is possible to classify road conditions intuitively. The robot controller is designed by considering the decoupled modal coordinate system, which consists of translational and rotational modes. Modal decomposition is performed by using a quarry matrix. Once the robot is provided with the ability to recognize tactile sensations, its usefulness to humans will increase. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 177(2): 49–57, 2011; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.21169
Flexible job‐shop scheduling problem by genetic algorithm
Authors: Ida Kenichi , Oka Kensaku
Published: July 2011

The Flexible Job‐shop Scheduling Problem is an expansion of the traditional Job‐shop Scheduling Problem in which an operation can be processed by one or more machines. The purpose of this problem is to look for the smallest makespan. For that purpose, it is necessary to decide the optimal assignment of machines to operations and the order of operations on machines. In this paper, we focus on the maximum of the workloads for all machines and propose a new method of survival selection, a method of creation of the initial solution, mutation, and a method of escape to the genetic algorithm for this problem. The efficacy of our method is demonstrated by comparing its numerical experiment results with those of other methods. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 177(3): 28–35, 2011; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.21194
New N,N,N‐Donors Resulting in Highly Active Ruthenium Catalysts for Transfer Hydrogenation at Room Temperature
Authors: Ghoochany Leila Taghizadeh , Farsadpour Saeid , Sun Yu , Thiel Werner R.
Published: July 2011

A series of ruthenium complexes of the general formula [RuCl2(L)(NNN)] were synthesized starting from tridentate N,N,N‐ligands containing pyridine and allylated pyrazole donor groups and [RuCl2(PPh3)3]. The N,N,N‐donors introduced herein are accessible in a few steps from versatile precursors. The primary products, [RuCl2(NNN)(PPh3)], can be converted into the corresponding carbonyl complexes, [RuCl2(CO)(NNN)], by bubbling CO into a solution in toluene at elevated temperatures. All ruthenium complexes were investigated as catalysts for the transfer hydrogenation of aryl ketones. The phosphane complexes show high activities with turnover frequency values of up to 1200 h–1 in the presence of just one equivalent of KOH, whereas the carbonyl complexes are only poorly active.
A Modular Approach towards the Synthesis of Target‐Specific MRI Contrast Agents
Authors: Verwilst Peter , Eliseeva Svetlana V. , Carron Sophie , Vander Elst Luce , Burtea Carmen , Dehaen Geert , Laurent Sophie , Binnemans Koen , Muller Robert N. , Parac‐Vogt Tatjana N. , De Borggraeve Wim M.
Published: July 2011

In this paper, a modular pathway towards the synthesis of new specific MRI contrast agents and their luminescent analogues is described. Using two azide‐bearing probes, 3β‐deoxycholic acid and cRGDfK(N3), we performed a “click” reaction with an alkyne‐bearing 1,4,7,10‐tetraazacyclododecane‐1,4,7,10‐tetraacetic acid (DOTA) analogue, yielding a possible blood‐pool contrast agent, as well as a contrast agent with a high affinity for cells expressing αvβ3 integrin. The nuclear magnetic relaxation dispersion (NMRD) profiles and human serum albumin (HSA) titration of the contrast agent bearing deoxycholic acid show that this contrast agent interacts with HSA. T1 measurements of Jurkat T cells in the presence of the contrast agent proved the retention of the integrin‐binding property of the RGD‐bearing contrast agent.
Influence of physical pretreatments of sheanuts (Vitellaria paradoxa Gaertn.) on butter quality
Authors: Bup Divine Nde , Kapseu César , Matos Louis , Mabiala Bernard , Mouloungui Zéphirin
Published: July 2011

Shea butter, usually extracted from kernels of Vitellaria paradoxa Gaertn. by rural women in Sub‐Saharran Africa, has multiple traditional and industrial uses. Traditional processing methods are not standardized and often lead to the production of poor quality butter, which attract low market prices. The aim of this work was to study the different pretreatments locally applied to sheanuts during processing in order to identify those that can affect butter quality. The effect of cooking, soaking as well as drying on the amount of butter extracted and its minor constituents were investigated. All these pretreatments significantly affected oil quality. The effect of soaking of the kernels on improving oil extraction yields (55%) was comparable to that of kernels digested with α‐amylase, acid protease, cellulase/hemicellulase, pectinase, and glucanase enzymes before oil extraction reported in the literature. Drying had a significant negative effect on tocopherol contents of the oil. However, residual amounts of tocopherols in the oil after drying were high enough to suggest that it may still confer anti‐oxidant activities. Soaking, cooking, and drying are important pretreatments involved in the production of shea butter locally that need to be standardized in order to produce better quality butter.

Practical applications: In this work, we carried out scientific analysis of methods already used by rural women to process shea fruits into shea butter. This work should be useful for establishing processing conditions for obtaining good quality shea butter.
Lipids, curvature, and nano‐medicine
Authors: Mouritsen Ole G.
Published: July 2011

The physical properties of the lamellar lipid‐bilayer component of biological membranes are controlled by a host of thermodynamic forces leading to overall tensionless bilayers with a conspicuous lateral pressure profile and build‐in curvature‐stress instabilities that may be released locally or globally in terms of morphological changes. In particular, the average molecular shape and the propensity of the different lipid and protein species for forming non‐lamellar and curved structures are a source of structural transitions and control of biological function. The effects of different lipids, sterols, and proteins on membrane structure are discussed and it is shown how one can take advantage of the curvature‐stress modulations brought about by specific molecular agents, such as fatty acids, lysolipids, and other amphiphilic solutes, to construct intelligent drug‐delivery systems that function by enzymatic triggering via curvature.

Practical applications: The simple concept of lipid molecular shape and how it impacts on the structure of lipid aggregates, in particular the curvature and curvature stress in lipid bilayers and liposomes, can be exploited to construct liposome‐based drug‐delivery systems, e.g., for use as nano‐medicine in cancer therapy. Non‐lamellar‐forming lysolipids and fatty acids, some of which may be designed to be prodrugs, can be created by phospholipase action in diseased tissues thereby providing for targeted drug release and proliferation of molecular entities with conical shape that break down the permeability barrier of the target cells and may hence enhance efficacy.
Concise Pathway to New Multifunctionalized Constrained Pentacin Derivatives by Means of Two Stereospecific Tandem Reactions
Authors: Coursindel Thibault , Martinez Jean , Parrot Isabelle
Published: July 2011

Starting from Boc‐activated diketopiperazines, original bicyclic derivatives of trans‐ and cis‐2‐aminocyclopentanecarboxylic acid were prepared by using two stereospecific tandem reactions. One of them is a tandem transannular rearrangement of activated lactams/alkylation process leading to the stereoselective synthesis of suitably chiral pyrrolidine‐2,4‐diones, allowing subsequent Michael‐initiated ring closure, a simple and concise route to original multifunctionalized alicyclic β‐amino esters.
Polystyrene/graphene composite electrode fabricated by in situ polymerization for capillary electrophoretic determination of bioactive constituents in Herba Houttuyniae
Authors: Lu Yan , Wang Xia , Chen Daofeng , Chen Gang
Published: July 2011

A novel graphene/polystyrene composite electrode was developed for the enhanced amperometric detection of CE in this work. The composite electrode was fabricated on the basis of the in situ polymerization of a mixture of graphene and prepolymerized styrene in the bore of a piece of fused‐silica capillary under heat. SEM, XRD, and FTIR offered insights into the nature of the composite. The results indicated that graphenes were well dispersed and embedded throughout the PS matrix to form an interconnected conducting network. The performance of this unique graphene‐based detector has been demonstrated by separating and detecting rutin, isoquercitrin, quercitrin, and chlorogenic acid in Herba Houttuyniae (a traditional Chinese medicine) in combination with CE. The prepared graphene‐based CE detector offered significantly lower detection potential, yielded enhanced signal‐to‐noise characteristics, and exhibited high resistance to surface fouling and enhanced stability. It showed long‐term stability and reproducibility with a relative standard deviation of 3.1% for the peak current (n=15).
Soil seed bank composition and distribution on eroded slopes in the hill‐gully Loess Plateau region (China): influence on natural vegetation colonization
Authors: Wang Ning , Jiao Ju‐Ying , Jia Yan‐Feng , Zhang Xiao‐an
Published: July 2011

On the Chinese Loess Plateau, serious slope and gully erosion have caused a decrease in soil water capacity and fertility, which has resulted in vegetation degradation and a reduction in agricultural productivity. Great efforts have been made to restore vegetation to control soil erosion, but the efficiency of artificial revegetation is not satisfactory. Natural revegetation is an alternative. However, while soil seed banks are an essential source for natural revegetation, their composition and distribution on eroded slopes remains unknown. In addition, whether or not seed loss during soil erosion limits vegetation colonization is also unknown. In this work, soil seed bank composition and distribution were studied in three situations. Specifically, three main microsites were selected as sampling plots: fish‐scale pits, as artificial deposited micro‐topography; under tussocks, as trap microsites; and open areas, as eroded areas. Soil samples were collected at depths of 0–2 cm, 2–5 cm and 5–10 cm. The soil seed bank was identified using germination experiments, and a total of 34 species were identified. The dominant species in the soil seed bank were annual/biennial herbs with an average proportion more than 90% and density reaching 19,000 seeds m‐2. The pioneer species Artemisia scoparia was especially abundant. The dominant later successional species, such as Lespedeza davurica, Artemisia giraldii, Artemisia gmelinii, Stipa bungeana and Bothriochloa ischcemum, were present in the soil at a density that ranged from 38 to 1355 seeds m‐2. Compared with the eroded open areas, the fish‐scale pits retained a higher density of seeds, and the tussocks retained a larger number of species. However, there was no serious reduction of the soil seed bank in the erosion areas. The present study indicates that, on these eroded slopes, the soil seed bank is not the key factor limiting the colonization of natural vegetation. Copyright © 2011 John Wiley & Sons, Ltd.
Expansion rate and geometry of floating vegetation mats on the margins of thermokarst lakes, northern Seward Peninsula, Alaska, USA
Authors: Parsekian Andrew D. , Jones Benjamin M. , Jones Miriam , Grosse Guido , Walter Anthony Katey M. , Slater Lee
Published: July 2011

Investigations on the northern Seward Peninsula in Alaska identified zones of recent (<50 years) permafrost collapse that led to the formation of floating vegetation mats along thermokarst lake margins. The occurrence of floating vegetation mat features indicates rapid degradation of near‐surface permafrost and lake expansion. This paper reports on the recent expansion of these collapse features and their geometry is determined using geophysical and remote sensing measurements. The vegetation mats were observed to have an average thickness of 0.57 m and petrophysical modeling indicated that gas content of 1.5–5% enabled floatation above the lake surface. Furthermore, geophysical investigation provides evidence that the mats form by thaw and subsidence of the underlying permafrost rather than terrestrialization. The temperature of the water below a vegetation mat was observed to remain above freezing late in the winter. Analysis of satellite and aerial imagery indicates that these features have expanded at maximum rates of 1–2 m yr‐1 over a 56 year period. Including the spatial coverage of floating ‘thermokarst mats’ increases estimates of lake area by as much as 4% in some lakes. Copyright © 2011 John Wiley & Sons, Ltd.
Comparative toxicity of eight oil dispersants, Louisiana sweet crude oil (LSC), and chemically dispersed LSC to two aquatic test species
Authors: Hemmer Michael J , Barron Mace G , Greene Richard M
Published: July 2011

The present study describes the acute toxicity of eight commercial oil dispersants, South Louisiana sweet crude oil (LSC), and chemically dispersed LSC. The approach used consistent test methodologies within a single laboratory in assessing the relative acute toxicity of the eight dispersants, including Corexit 9500A, the predominant dispersant applied during the DeepWater Horizon spill in the Gulf of Mexico. Static acute toxicity tests were performed using two Gulf of Mexico estuarine test species, the mysid shrimp (Americamysis bahia) and the inland silversides (Menidia beryllina). Dispersant-only test solutions were prepared with high-energy mixing, whereas water-accommodated fractions of LSC and chemically dispersed LSC were prepared with moderate energy followed by settling and testing of the aqueous phase. The median lethal concentration (LC50) values for the dispersant-only tests were calculated using nominal concentrations, whereas tests conducted with LSC alone and dispersed LSC were based on measured total petroleum hydrocarbon (TPH) concentrations. For all eight dispersants in both test species, the dispersants alone were less toxic (LC50s: 2.9 to >5,600 µl/L) than the dispersant–LSC mixtures (0.4–13 mg TPH/L). Louisiana sweet crude oil alone had generally similar toxicity to A. bahia (LC50: 2.7 mg TPH/L) and M. beryllina (LC50: 3.5 mg TPH/L) as the dispersant–LSC mixtures. The results of the present study indicate that Corexit 9500A had generally similar toxicity to other available dispersants when tested alone but was generally less toxic as a mixture with LSC. Environ. Toxicol. Chem. 2011;30:2244–2252. © 2011 SETAC
Perfluorinated chemicals in surface waters and sediments from northwest Georgia, USA, and their bioaccumulation in Lumbriculus variegatus
Authors: Lasier Peter J , Washington John W , Hassan Sayed M , Jenkins Thomas M
Published: July 2011

Concentrations of perfluorinated chemicals (PFCs) were measured in surface waters and sediments from the Coosa River watershed in northwest Georgia, USA, to examine their distribution downstream of a suspected source. Samples from eight sites were analyzed using liquid chromatography-tandem mass spectrometry. Sediments were also used in 28-d exposures with the aquatic oligochaete, Lumbriculus variegatus, to assess PFC bioaccumulation. Concentrations of PFCs in surface waters and sediments increased significantly below a land-application site (LAS) of municipal/industrial wastewater and were further elevated by unknown sources downstream. Perfluorinated carboxylic acids (PFCAs) with eight or fewer carbons were the most prominent in surface waters. Those with 10 or more carbons predominated sediment and tissue samples. Perfluorooctane sulfonate (PFOS) was the major homolog in contaminated sediments and tissues. This pattern among sediment PFC concentrations was consistent among sites and reflected homolog concentrations emanating from the LAS. Concentrations of PFCs in oligochaete tissues revealed patterns similar to those observed in the respective sediments. The tendency to bioaccumulate increased with PFCA chain length and the presence of the sulfonate moiety. Biota-sediment accumulation factors indicated that short-chain PFCAs with fewer than seven carbons may be environmentally benign alternatives in aquatic ecosystems; however, sulfonates with four to seven carbons may be as likely to bioaccumulate as PFOS. Environ. Toxicol. Chem. 2011;30:2194–2201. © 2011 SETAC
Selenium bioaccumulation and speciation in Chironomus dilutus exposed to water-borne selenate, selenite, or seleno-DL-methionine
Authors: Franz Eric D , Wiramanaden Cheryl I. E , Janz David M , Pickering Ingrid J , Liber Karsten
Published: July 2011

The objective of the present study was to describe the uptake and elimination kinetics of selenium (Se) administered in the forms of selenate, selenite, and selenomethionine (seleno-DL-methionine) in different life stages of the midge Chironomus dilutus, and to determine the relationship between Se bioavailability and Se speciation using X-ray absorption spectroscopy (XAS). Midge larvae exposed to 4.3 µg/L as dissolved selenate for 10 d of had negligible accumulation of Se (indistinguishable from control organisms). However, larvae rapidly accumulated Se over 10 d of exposure to 3.8 and 1.8 µg/L selenite and seleno-DL-methionine (Se-met), respectively. Most Se accumulated by larvae exposed to selenite or Se-met was retained after 10 d of elimination in clean water. When additional midge larvae were exposed to Se until emergence, Se accumulated during the larval stage was largely retained in the adults. Although a strong correlation was found between the adult whole-body Se concentration and the Se concentration in the exuvia after emergence, only a minor loss of Se occurred in the shed exuvia compared with larvae and adult whole-body concentrations. X-ray absorption spectroscopy analysis showed that organic selenides and diselenides, modeled as Se-met and selenocystine, respectively, were the dominant forms of Se in both the larval and adult insect stages. The proportion and concentration of organic selenides (selenomethionine) increased in larvae and adults exposed to Se-met and selenite compared with larvae exposed to selenate, whereas the concentration of diselenides (selenocystine) remained relatively constant for all treatments. Environ. Toxicol. Chem. 2011;30:2292–2299. © 2011 SETAC
Direct numerical simulation of modulation of isotropic turbulence by poly‐dispersed particles
Authors: Kondaraju Sasidhar , Choi Moonho , Xu Xiaofeng , Lee Joon Sang
Published: July 2011

A direct numerical simulation technique based on two‐way coupling is presented to study a particle‐laden, decaying isotropic turbulent flow. Physical characteristics of turbulence modulation because of the mono‐dispersed (i.e., particles with single Stokes number) and poly‐dispersed particles (i.e., particles with more than one Stokes number) were investigated. A scale dependent effective viscosity that summarizes the aspects of the interaction between the velocity field and particles is defined in the study. Particles of Stokes number (St) 3.2,6.4 and 12.8 were used in performing the simulations. Poly‐dispersed particles were acquired by mixing particles of two different Stokes numbers at a time. As a whole, decay of turbulence because of the poly‐dispersed particles is observed to be larger than that of the decay of turbulence because of the mono‐dispersed particles. Simulations of poly‐dispersed particle indicate nonlinear characteristics in the modification of the temporal evolution of turbulence energy and dissipation. The scale dependent effective viscosity, which correlates with the energy spectrum plot, indicates that the decay of turbulence is mostly observed at the intermediate scales of turbulence. The effective viscosity for the simulations of the poly‐dispersed particles was calculated to be higher than that of the simulations of the mono‐dispersed particles. Copyright © 2011 John Wiley & Sons, Ltd.
A novel peristaltic micropump with low compression ratios
Authors: Tsui Yeng‐Yung , Chang Tso‐Chang
Published: July 2011

It is common for peristaltic micropumps to have large compression ratios. In the limit, the chamber of the pump is completely blocked by the membrane to prevent back flow. Different from this kind of pump, a micropump with small compression ratios is proposed in this study. With small oscillation amplitudes the membrane of the pump can reciprocate at high frequencies to improve its pumping flow. Both the multidimensional method and the lumped‐element method are employed for analysis. For this kind of peristaltic micropump the working fluid is allowed to flow freely in the forward and backward directions. Therefore, the operating sequences for the high‐compression ratio type of pumps are not appropriate. It is shown that the theoretical net flow rate is zero for the four‐phase and six‐phase modes of sequence and becomes negative for the three‐phase mode unless regulators, such as the nozzle/diffusers, are incorporated to rectify the flow. However, this pump becomes very attractive by reversing the operating sequence of the three‐phase mode because positive net flow is yielded. It is seen that with the reversed three‐phase mode and the nozzle/diffuser as connecting channels, the pumping effectiveness is greatly enhanced. The pumps with both two chambers and three chambers are under consideration in the study. Copyright ©2011 John Wiley & Sons, Ltd.
Soret and Dufour effects on heat and mass transfer by mixed convection over a vertical surface saturated porous medium with temperature dependent viscosity
Authors: EL‐Kabeir S.M.M.
Published: July 2011

The diffusion‐thermo and thermal‐diffusion effects on heat and mass transfer by mixed convection boundary layer flow over a vertical isothermal permeable surface embedded in a porous medium were studied numerically in the presence of chemical reaction with temperature‐dependent viscosity. The governing nonlinear partial differential equations are transformed into a set of coupled ordinary differential equations, which are solved numerically by using Runge–Kutta method with shooting technique. Numerical results are obtained for the velocity, temperature and concentration distributions, and the local skin friction coefficient, local Nusselt number and local Sherwood number for several values of the parameters, namely, the variable viscosity parameter, suction/injection parameter, Darcy number, chemical reaction parameter, and Dufour and Soret numbers. The obtained results are presented graphically and in tabulated form, and the physical aspects of the problem are discussed. Copyright © 2011 John Wiley & Sons, Ltd.
Sensitivity of Stresses and Failure Mechanisms in SOFCs to the Mechanical Properties and Geometry of the Constitutive Layers
Authors: Nakajo A. , Van herle J. , Favrat D.
Published: July 2011

A model based on the Euler–Bernoulli theory is used to assess the sensitivity of residual stresses in solid oxide fuel cells to the mechanical properties and geometry of the constituents. It considers different cell configurations, characterised by the presence or not of a compensating layer, and a cathode based on either lanthanum strontium manganite (LSM) or lanthanum strontium cobaltite ferrite (LSCF). The implementation of creep in the model provides insights into the parameters that affect the zero‐stress temperature and behaviour during ageing. The amount of irreversible deformation generated in the cell layers after the sintering step depends on the mechanical properties of the layers, type of cell and to some extent, cooling rate. X‐ray diffraction measurements from literature are used to verify the prediction. Depending on the mechanical properties, the stress state in the LSM cathode changes from tensile to compressive with respect to temperature. During combined ageing and thermal cycling, tensile stress might arise in the compatibility layer of LSCF‐based cells, due to the relief of the initial compressive stress at operating temperature. The Weibull analysis provides the assessment of mechanical failure. A simplified approach is used for buckling‐driven delamination, but the propagation of cracks is predicted for unlikely large pre‐existing defects.
Planar Metal‐Supported SOFC with Novel Cermet Anode
Authors: Blennow P. , Hjelm J. , Klemensø T. , Persson Å. H. , Ramousse S. , Mogensen M.
Published: July 2011

Metal‐supported solid oxide fuel cells are expected to offer several potential advantages over conventional anode (Ni‐YSZ) supported cells. For example, increased resistance against mechanical and thermal stresses and a reduction in material costs. When Ni‐YSZ based anodes are used in metal supported SOFC, elements from the active anode layer may inter‐diffuse with the metallic support during sintering. This work illustrates how the inter‐diffusion problem can be circumvented by using an alternative anode design based on porous and electronically conducting layers, into which electrocatalytically active materials are infiltrated after sintering. The paper presents the electrochemical performance and durability of the novel planar metal‐supported SOFC design. The electrode performance on symmetrical cells has also been evaluated. The novel cell and anode design shows a promising performance and durability at a broad range of temperatures and is especially suitable for intermediate temperature operation at around 650 °C.
Influence of Compressive Stress on the Water Content of Perfluorosulphonated Membranes: A μ‐Raman Study
Authors: Sutor A. K. , Huguet P. , Morin A. , Gebel G. , Le T. S. , Deabate S.
Published: July 2011

The effect of compressive stress on the local water content of Nafion NRE 212 and Aquivion E79 membranes is studied by confocal μ‐Raman spectroscopy using a specific tightening device. This device aims to mimic the geometry of the bipolar plate flow field of actual fuel cells, i.e. the sequence of channels and ribs. The membrane water content decreases with increasing stress, under the ribs as well as in the channel. The higher the initial water content, the larger the water content decreases with mechanical stress. The extent of water loss depends on the position of the membrane in the device, the applied stress and the hydration history of the membrane.
Optimal hedging with higher moments
Authors: Brooks Chris , Černý Alešs , Miffre Joëlle
Published: July 2011

This study proposes a utility‐based framework for the determination of optimal hedge ratios (OHRs) that can allow for the impact of higher moments on hedging decisions. We examine the entire hyperbolic absolute risk aversion family of utilities which include quadratic, logarithmic, power, and exponential utility functions. We find that for both moderate and large spot (commodity) exposures, the performance of out‐of‐sample hedges constructed allowing for nonzero higher moments is better than the performance of the simpler OLS hedge ratio. The picture is, however, not uniform throughout our seven spot commodities as there is one instance (cotton) for which the modeling of higher moments decreases welfare out‐of‐sample relative to the simpler OLS. We support our empirical findings by a theoretical analysis of optimal hedging decisions and we uncover a novel link between OHRs and the minimax hedge ratio, that is the ratio which minimizes the largest loss of the hedged position. © 2011 Wiley Periodicals, Inc. Jrl Fut Mark 32:909–944, 2012
“I know you can hear me”: Neural correlates of feigned hearing loss
Authors: McPherson Bradley , McMahon Katie , Wilson Wayne , Copland David
Published: July 2011

In the assessment of human hearing, it is often important to determine whether hearing loss is organic or nonorganic in nature. Nonorganic, or functional, hearing loss is often associated with deceptive intention on the part of the listener. Over the past decade, functional neuroimaging has been used to study the neural correlates of deception, and studies have consistently highlighted the contribution of the prefrontal cortex in such behaviors. Can patterns of brain activity be similarly used to detect when an individual is feigning a hearing loss? To answer this question, 15 adult participants were requested to respond to pure tones and simple words correctly, incorrectly, randomly, or with the intent to feign a hearing loss. As predicted, more activity was observed in the prefrontal cortices (as measured by functional magnetic resonance imaging), and delayed behavioral reaction times were noted, when the participants feigned a hearing loss or responded randomly versus when they responded correctly or incorrectly. The results suggest that cortical imaging techniques could play a role in identifying individuals who are feigning hearing loss. Hum Brain Mapp, 2012. © 2011 Wiley Periodicals, Inc