bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of proximity and activity on visual and auditory monitoring in wild Japanese Macaques
Authors: Suzuki Mariko , Sugiura Hideki
Published: February 2011

Group‐living primates monitor group members to maintain the spatial cohesiveness of the group. We examined the possibility that visual scanning (turning the head for more than 3 sec) and contact calls (coo calls) function as visual and auditory monitoring behaviors to avoid separation from group members in wild Japanese macaques. The rate of visual scanning increased as proximity to group members decreased and as mobile activities (foraging and moving) increased, compared with immobile activities (resting and grooming). However, the rate of contact calls varied differently with proximity and activities. During resting and moving, the rate of contact calls increased as proximity decreased. In contrast, the rate increased with closer proximity during feeding. Visual scanning during all activities and contact calls during resting and moving increased when the group members were likely to spread over a larger area, suggesting that these behaviors functioned as monitoring of group members to avoid separation from the group. Contact calls also increased when the group members stayed in close proximity during foraging, suggesting that this behavior was also associated with competitive situations. Contact calls may also function to ease tension or maintain distance to avoid conflict in competitive situations. Am. J. Primatol. 73:623–631, 2011. © 2011 Wiley‐Liss, Inc.
Crystal morphology and structure of the β‐form of isotactic polypropylene under supercooled extrusion
Authors: Zhang Bin , Chen Jingbo , Zhang Xiaoli , Shen Changyu
Published: February 2011

A supercooled melt of isotactic polypropylene (iPP) was extruded through a capillary die. Polarized light microscopy (PLM), wide‐angle X‐ray diffraction (WAXD), and differential scanning calorimetry (DSC) were used to investigate the effects of the relatively weak wall shear stress (σw), extrusion temperature (Te), and crystallization temperature (Tc) on the structure and morphology of β‐form isotactic polypropylene (β‐iPP). β‐cylindrites crystals could be observed by PLM in the extruded specimen even at a lower σw's (0.020 MPa), and the β‐iPP content increased with decreasing Te. Under a given Te of 150°C, the increase in σw positively influenced the β‐iPP content. The DSC and WAXD results indicate that the total crystallinity and β‐iPP content increased when Tc was set from 105 to 125°C; the other experimental parameters were kept on the same level. Although Tc was above 125°C, the β‐iPP content obviously decreased, and the total crystallinity continued to increase. On the basis of the influences of σw, Te, and Tc on the β‐iPP crystal morphology and structure, a modified model is proposed to explain the growing of shear‐induced β‐iPP nucleation. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
The use of carbon nanotubes in textile printing
Authors: Krucińska Izabella , Skrzetuska Ewa , Urbaniak‐Domagała Wiesława
Published: February 2011

The characteristic properties of carbon nanotubes (CNTs), particularly their heat conduction, electrical conductivity, high modulus of elasticity, high strength, and resistance to chemicals, have resulted in widespread application of CNTs in nanotechnologies. In this study, CNTs were used to impart specific functionality to textiles by printing techniques. To this aim, modified commercial aqueous dispersions of multiwalled CNTs from Nanocyl® were used for preparing special compositions as paste for printing by conventional techniques (screen printing) and as inks for ink‐jet printing to bestow the fabric antistatic and antibacterial properties. Taking into account the importance of the dispersion level of CNT in the printing composition from the point of view of antistatic properties, the quality of the CNT dispersion was assessed on the basis of particle size distribution by means of a DLS PSS Nicomp device. Printings were done on two types of woven fabrics: 100% cotton and 30/70% cotton/polyester blend. The CNTs used in printing were found to impart antistatic and antibacterial properties to the printed fabrics. These imparted properties were resistant to repeated washing. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Synthesis and characterization of Polymethacrylamide–Clay nanocomposites
Authors: Anbarasan R. , Arvind P. , Dhanalakshmi V.
Published: February 2011

Polymethacrylamide intercalated hectorite clay nanocomposites were synthesized by the in situ free‐radical polymerization method. The interlayer cation of hectorite clay was modified with cetyl pyridinium chloride and cetrimide, and their effects on the rate of polymerization of methacrylamide and the structure–property relationships of the resulting polymer nanocomposites were investigated. Fourier transform infrared spectroscopy showed a peak around 550 cm−1 that was due to the metal oxide stretching of hectorite clay in the polymer nanocomposites. High‐resolution transmission electron microscopy determined the size of polymethacrylamide as 300 nm. X‐ray diffraction was used for the determination of the intercalated products. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Degradation of high‐impact polystyrene with processing and its recovery via the addition of styrene–butadiene rubber and styrene–ethylene–butylene–styrene block copolymer
Authors: Parres F. , Crespo J. E.
Published: February 2011

This work was divided into three parts. First, high‐impact polystyrene (HIPS) was submitted to a series of extrusion cycles with the objective of evaluating the consequent variations in its thermal and mechanical properties. The results showed slight variations in both the thermal and mechanical properties of HIPS. Second, degraded HIPS/styrene–ethylene–butylene–styrene (SEBS) blends and degraded HIPS/styrene–butadiene rubber (SBR) blends were prepared to evaluate the influence of the elastomeric concentration on the polymer's properties. The incorporation of SEBS or SBR allowed the recovery of the initial properties shown by virgin HIPS. Finally, blends of degraded HIPS with 2 wt % SEBS or SBR were extruded through four cycles. The mechanical properties remained constant with 2% SEBS added, whereas the mixtures of HIPS with 2% SBR showed an increase in the tensile strength as the number of extrusion cycles increased. The Vicat softening temperature decreased in both cases. The use of differential scanning calorimetry permitted the observation of differences in the crosslinking reactions of different samples as a function of the number of extrusion cycles. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Controllable properties and microstructure of hydrogels based on crosslinked poly(ethylene glycol) diacrylates with different molecular weights
Authors: Zhang Hongbin , Wang Lei , Song Li , Niu Guoguang , Cao Hui , Wang Guojie , Yang Huai , Zhu Siquan
Published: February 2011

This work describes a comprehensive study of hydrogels based on polyethylene glycol diacrylates (PEGDAs) with the molecular weight (MW) range of 400–2000. The blends of low‐ and high‐molecular weight PEGDA macromers with different ratios were photopolymerized under visible light irradiation, using a blue light sensitive photoinitiator Irgacure819, at the total polymer concentration of 60 wt %. Swelling ratios, wetting property, elastic moduli, transparency, and the microstructure of the resulting hydrogels were investigated. Among them, equilibrium water contents, hydrophilicity, and mesh size of the hydrogels increased while the elastic moduli decreased when increased the PEGDA MW or the content of higher MW PEGDA in the blends. Most of the hydrogels possessed excellent transparency in visible region. The viability of L929 cells on the surface of hydrogel was also estimated. All the selected hydrogels exhibited a relatively high proliferation rate, which demonstrated this hydrogel system with photoinitiator Irgacure819 had good biocompatibility. These results show the properties of PEGDA hydrogel could be easily adjusted by varying PEGDA MW or the ratios of low‐ and high‐MW macromers in the composites. It could be helpful for the design of proper PEGDA hydrogels in the applications as tissue engineering or drug delivery system. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
An efficient method for nitration of aromatic compounds over solid acid and polymer‐supported sodium nitrite
Authors: Karimi Zarchi Mohammad Ali , Rahmani Fahimeh
Published: February 2011

A variety of aromatic compounds are nitrated under heterogeneous conditions using a polymer‐supported hydrochloric acid, [P4‐(VP)]HCl, with a polymer‐supported sodium nitrite, [P4‐VP]NO2, or sodium nitrite in ethanol at room temperature with high yields. This methodology is useful for nitration of activated aromatic compounds. In this procedure, the work‐up is very easy, and the spent polymeric reagent can be regenerated and reused. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Role of interface on dynamic modulus of high‐performance poly(etheretherketone)/ceramic composites
Authors: Goyal R. K. , Tiwari A. N. , Negi Y. S.
Published: February 2011

High‐performance printed circuit board or electronic packaging substrate with low warping particularly at high frequency is the key demand of manufacturers. In the present work, poly(etheretherketone) (PEEK) matrix composites reinforced with untreated micron size aluminum nitride (AlN) and alumina (Al2O3) particles have been studied for dynamic modulus in the temperature range varying from 30 to 250°C. At 48 vol % particles, the room temperature modulus of the PEEK/AlN composites increased by approximately fivefold (∼ 23 GPa), whereas it increased by twofold for PEEK/Al2O3composite. The reinforcing efficiency is more pronounced at higher temperatures. The significant improvement in modulus was attributed to the better adhesion between the matrix and the AlN particles. Scanning electron microscope (SEM) and Kubat parameter showed that the poor adhesion between the matrix and the Al2O3particles resulted in comparatively smaller increase in modulus of PEEK/Al2O3, despite higher intrinsic modulus of Al2O3than that of AlN. SEM showed almost uniform distribution of particles in the matrix. The experimental data were correlated with several theoretical models. The Halpin–Tsai model with ξ (xi) is equal to four correlates well up to 48 vol % AlN composites while ξ is equal to two correlates only up to 18 vol % Al2O3composites. Guth–Smallwood model also correlates well up to 28 vol % AlN and 18 vol % Al2O3‐filled composites. Thereafter, data deviated from it due to the particles tendency to aggregate formation. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Synthesis of chitin‐polyaniline nanocomposite by electron beam irradiation
Authors: Ramaprasad A. T. , Rao Vijayalakshmi , Sanjeev Ganesh
Published: February 2011

In this article, we report a novel method to synthesize polyaniline (PANI) nanocomposite. Chitin and PANI are dissolved in a common solvent, N,N‐dimethyl acetamide, with 5% LiCl, and the solution is irradiated with 8 MeV electron beam for different doses, nanoparticles of PANI in chitin is obtained. The characterization of the composite was done by UV–vis absorption spectrum, FTIR, thermogravimetric analysis (TGA), X‐ray diffraction, scanning electron microscopic (SEM), and DC conductivity studies. UV–vis studies show conversion of emeraldine base form to leucoemaraldine base. FTIR studies show interaction between chitin and PANI. SEM analysis of irradiated composite shows formation of PANI particulates. Average particle size varies from ≈40 to ≈1000 nm. DC conductivity of blend improves on irradiation. One‐dimensional variable range hopping conduction mechanism is dominating in the irradiated blend. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Performance and biodegradability of a maleated polyester bioplastic/recycled sugarcane bagasse system
Authors: Wu Chin‐San
Published: February 2011

The biodegradability, morphology, and mechanical properties of composite materials made of poly(butylene succinate adipate) (PBSA) and sugarcane bagasse (SCB) were evaluated. Composites containing maleic anhydride (MA)‐grafted PBSA (PBSA‐g‐MA/SCB) exhibited noticeably superior mechanical properties because of greater compatibility between the two components. The dispersion of SCB in the PBSA‐g‐MA matrix was highly homogeneous as a result of ester formation between the carboxyl groups of PBSA‐g‐MA and hydroxyl groups in SCB and the consequent creation of branched and crosslinked macromolecules. Each composite was subjected to biodegradation tests in a Rhizopus oryzae compost. Morphological observations indicated severe disruption of film structure after 60 days of incubation, and both the PBSA and the PBSA‐g‐MA/SCB composite films were eventually completely degraded. The PBSA‐g‐MA/SCB films were more biodegradable than those made of PBSA and exhibited a higher intrinsic viscosity, implying a strong connection between these characteristics and biodegradability. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Geophysical prospection of a bronze foundry on the southern slope of the acropolis at athens, Greece
Authors: Leopold Matthias , Gannaway Evey , Völkel Jörg , Haas Florian , Becht Michael , Heckmann Tobias , Westphal Markus , Zimmer Gerhard
Published: February 2011

The sanctuary of the Acropolis of Athens in Greece provided one of the first monumental bronze statues some 2500 years ago, which was dedicated to the goddess Athena. During recent decades, important understanding of the statue's manufacturing processes has been achieved by archaeological studies, and the former production site has been identified on the southern slope of the Acropolis. Two major bronze production pits have been detected and one was excavated in 2001 and 2006 and was found in an unexpected location. Therefore, in 2010 a geophysical survey of the whole production site was carried out for the first time in order to either reveal or to exclude any further sites of the bronze foundry complex. A combination of different geophysical methods was applied to survey the subsurface; magnetometry (MAG), two‐ and three‐dimensional electrical resistivity tomography (ERT), as well as two‐ and three‐dimensional ground‐penetrating radar (GPR). Two major anomalies have been identified in the processed data, which provide evidence for additional production sites. One was a known site identified in a test trench in 2001, and our survey has outlined the extent of the former pit. The other anomaly, which was detected by ERT and GPR, was 8–10 m in length and 2–3 m in width and is oval‐shaped and about 2.5 m deep. Steep vertical walls, together with two narrow points at the ends of the pit, which could reflect former entrances, were identified. Virtual ERT and GPR models generated from cross‐sections of a ground‐based LiDAR scan of the 2001 and 2006 excavated pit helped to interpret and understand the geophysical data of anomaly 2. This anomaly was finally interpreted as a newly detected production pit of the bronze foundry complex, and based on these findings new excavations are planned. Copyright © 2011 John Wiley & Sons, Ltd.
The scholarly impact of TRECVid (2003–2009)
Authors: Thornley Clare V. , Johnson Andrea C. , Smeaton Alan F. , Lee Hyowon
Published: February 2011

This paper reports on an investigation into the scholarly impact of the TRECVid (Text Retrieval and Evaluation Conference, Video Retrieval Evaluation) benchmarking conferences between 2003 and 2009. The contribution of TRECVid to research in video retrieval is assessed by analyzing publication content to show the development of techniques and approaches over time and by analyzing publication impact through publication numbers and citation analysis. Popular conference and journal venues for TRECVid publications are identified in terms of number of citations received. For a selection of participants at different career stages, the relative importance of TRECVid publications in terms of citations vis à vis their other publications is investigated. TRECVid, as an evaluation conference, provides data on which research teams ‘scored’ highly against the evaluation criteria and the relationship between ‘top scoring’ teams at TRECVid and the ‘top scoring’ papers in terms of citations is analyzed. A strong relationship was found between ‘success’ at TRECVid and ‘success’ at citations both for high scoring and low scoring teams. The implications of the study in terms of the value of TRECVid as a research activity, and the value of bibliometric analysis as a research evaluation tool, are discussed.
Counting first, last, or all authors in citation analysis: A comprehensive comparison in the highly collaborative stem cell research field
Authors: Zhao Dangzhi , Strotmann Andreas
Published: February 2011

How can citation analysis take into account the highly collaborative nature and unique research and publication culture of biomedical research fields? This study explores this question by introducing last‐author citation counting and comparing it with traditional first‐author counting and theoretically optimal all‐author counting in the stem cell research field for the years 2004–2009. For citation ranking, last‐author counting, which is directly supported by Scopus but not by ISI databases, appears to approximate all‐author counting quite well in a field where heads of research labs are traditionally listed as last authors; however, first author counting does not. For field mapping, we find that author co‐citation analyses based on different counting methods all produce similar overall intellectual structures of a research field, but detailed structures and minor specialties revealed differ to various degrees and thus require great caution to interpret. This is true especially when authors are selected into the analysis based on citedness, because author selection is found to have a greater effect on mapping results than does choice of co‐citation counting method. Findings are based on a comprehensive, high‐quality dataset extracted in several steps from PubMed and Scopus and subjected to automatic reference and author name disambiguation.
Enhanced absorption of millimeter wave energy in murine subcutaneous blood vessels
Authors: Alekseev Stanislav I. , Ziskin Marvin C.
Published: February 2011

The aim of the present study was to determine millimeter wave (MMW) absorption by blood vessels traversing the subcutaneous fat layer of murine skin. Most calculations were performed using the finite‐difference time‐domain (FDTD) technique. We used two types of models: (1) a rectangular block of multilayer tissue with blood vessels traversing the fat layer and (2) cylindrical models with circular and elliptical cross‐sections simulating the real geometry of murine limbs. We found that the specific absorption rate (SAR) in blood vessels normally traversing the fat layer achieved its maximal value at the parallel orientation of the E‐field to the vessel axis. At 42 GHz exposure, the maximal SAR in small blood vessels could be more than 30 times greater than that in the skin. The SAR increased with decreasing the blood vessel diameter and increasing the fat thickness. The SAR decreased with increasing the exposure frequency. When the cylindrical or elliptical models of murine limbs were exposed to plane MMW, the greatest absorption of MMW energy occurred in blood vessels located on the lateral areas of the limb model. At these areas the maximal SAR values were comparable with or were greater than the maximal SAR on the front surface of the skin. Enhanced absorption of MMW energy by blood vessels traversing the fat layer may play a primary role in initiating MMW effects on blood cells and vasodilatation of cutaneous blood vessels. Bioelectromagnetics 32:423–433, 2011. © 2011 Wiley‐Liss, Inc.
Insulin increases macrophage triglyceride accumulation under diabetic conditions through the down regulation of hormone sensitive lipase and adipose triglyceride lipase
Authors: Meilin Edna , Aviram Michael , Hayek Tony
Published: February 2011

Diabetes mellitus (DM) is a major risk factor for the development of atherosclerosis, and high‐serum levels of insulin are strongly associated with type 2 DM. Atherosclerosis is characterized by lipid‐laden macrophage foam cell formations, which contain substantial amount of cholesterol and triglycerides (TG). This study analyzed for the first time, the effects of insulin on TG metabolism in macrophages under normal and diabetic conditions. Mouse peritoneal macrophages from C57BL6 mice were cultured under normal (5 mM) or high (diabetic condition, 25 mM) glucose concentration, with or without insulin, followed by the assessment of TGs metabolism in these cells. Under diabetic condition, insulin increased TG accumulation in macrophages by 100%, decreased cellular TG degradation by 21%, and increased C‐reactive protein levels in macrophages by 83%. Insulin decreased hormone‐sensitive lipase mRNA and protein expression by 28 and 60%, respectively, and adipose TG lipase (ATGL) protein expression by 36%, with no significant reduction in ATGL mRNA levels. The inhibition of insulin‐mediated phosphorylation, and the addition of cyclic adenosine 3′5′‐monoposphate, abolished the insulin‐mediated inhibition of TGs degradation in cells. Insulin increases macrophage TGs accumulation only under diabetic conditions, suggesting that impaired glycemic control in diabetic patients treated with insulin may contribute to foam cell formations and enhanced inflammation in macrophages.
Different Active‐Site Loop Orientation in Serine Hydrolases versus Acyltransferases
Authors: Jiang Yun , Morley Krista L. , Schrag Joseph D. , Kazlauskas Romas J.
Published: February 2011

Acyl transfer is a key reaction in biosynthesis, including synthesis of antibiotics and polyesters. Although researchers have long recognized the similar protein fold and catalytic machinery in acyltransferases and hydrolases, the molecular basis for the different reactivity has been a long‐standing mystery. By comparison of X‐ray structures, we identified a different oxyanion‐loop orientation in the active site. In esterases/lipases a carbonyl oxygen points toward the active site, whereas in acyltransferases a NH of the main‐chain amide points toward the active site. Amino acid sequence comparisons alone cannot identify such a difference in the main‐chain orientation. To identify how this difference might change the reaction mechanism, we solved the X‐ray crystal structure of Pseudomonas fluorescens esterase containing a sulfonate transition‐state analogue bound to the active‐site serine. This structure mimics the transition state for the attack of water on the acyl–enzyme and shows a bridging water molecule between the carbonyl oxygen mentioned above and the sulfonyl oxygen that mimics the attacking water. A possible mechanistic role for this bridging water molecule is to position and activate the attacking water molecule in hydrolases, but to deactivate the attacking water molecule in acyl transferases.
Repeated successful balloon valvuloplasty of a bioprosthetic aortic valve in a nonagenerian
Authors: Dejam Andre , Hokinson Michelle , Laham Roger
Published: February 2011

Calcific aortic stenosis remains a major cause of mortality and morbidity in the aging population. Surgical replacement remains the treatment of choice for this disease. Balloon aortic valvuloplasty was introduced as a palliative procedure for these patients, but was tempered by a high rate of recurrence, which has limited its usefulness. However, the introduction of smaller‐profile balloons, rapid pacing, and closure devices have brought it back as an alternative treatment strategy in selected patients who are at too high risk for surgery with repeat valvuloplasty as needed for recurrences. We report a case of prosthetic aortic valve stenosis treated with valvuloplasty with intracardiac and fluoroscopic guidance with recurrence treated with repeat valvuloplasty with promising intermediate‐term outcome and describe the growing valve in valve procedures. © 2011 Wiley‐Liss, Inc.
Myocardial infarction in a youngster Due to giant coronary aneurysm
Authors: Dhakam Sajid , Rahman Nasir
Published: February 2011

A 22‐year old male presented with acute inferior wall myocardial infarction. Coronary angiogram revealed normal left coronary arteries and a giant coronary aneurysm in Right coronary artery (RCA). Primary angioplasty of RCA was performed. Large thrombus burden was retrieved with aspiration device and coronary flow restored. However, despite best efforts some thrombus remained and decision to stent was deferred to a later date. Dimensions of aneurysm on quantitative coronary angiogram were 15 mm in width and 46 mm in length. Two weeks later coronary angiogram revealed normal flow in RCA without any angiographically visible thrombus. PCI was performed with two 3.0 × 28 mm Covered stents, Graft Master (JoStent) deployed across the aneurysm, overlapping each other. This completely sealed the aneurysm and intravascular ultrasound confirmed no leakage through the covered stents. Patient remains asymptomatic 2 months post procedure on triple antiplatelet therapy. © 2011 Wiley‐Liss, Inc.
Interstitial pore‐water temperature dynamics across a pool‐riffle‐pool sequence
Authors: Krause Stefan , Hannah David M. , Blume Theresa
Published: February 2011

Hyporheic habitat conditions are controlled strongly by spatial and temporal dynamics of physicochemical processes at the aquifer–river interface. In particular, heat transport between groundwater and surface water has a great impact on streambed habitats. This study uses high resolution observations of vertical hydraulic gradients (VHGs) and interstitial pore‐water temperatures to investigate space‐time patterns of groundwater–surface water (GW–SW) exchange fluxes and streambed thermal conditions of a pool‐riffle‐pool sequence of a UK lowland river. The results indicate that, although groundwater is dominantly upwelling in the research area, exchange flow patterns are strongly influenced by the streambed geomorphology. Advective heat flux caused by groundwater upwelling is shown to have a moderating impact on interstitial temperature patterns and partly compensates the impact of conduction of diurnal surface water temperature fluctuations into the streambed. Consequently, diurnal temperature oscillations, which are clearly pronounced in the top 10 cm of the streambed (up to 2 °C) are reduced by > 90% at depths below 20 cm. This study provides evidence that even in groundwater upwelling conditions, the spatially variable impact of heat conduction from the streambed surface may cause a spatially heterogeneous interstitial habitat structure with thermal conditions differing significantly in a vertical (3 °C temperature gradient at a length scale of 0·4 m) as well as longitudinal (0·75 °C at 16 m) domain. These results not only enhance the understanding of thermal patterns in lowland rivers but also have implications for interstitial habitat ecohydrology, community structures and stability. Copyright © 2011 John Wiley & Sons, Ltd.
Hydrological storage and transmission characteristics of an alpine talus
Authors: Muir Danika L. , Hayashi Masaki , McClymont Alastair F.
Published: February 2011

Alpine watersheds are the source region of some of the largest rivers in North America and elsewhere. Understanding of hydrological processes in alpine watersheds is important for understanding the response of river basins to meteorological forcing. Talus units in alpine watersheds have been suggested in the literature as potential reservoirs of groundwater, but relatively little is known about hydrological processes in talus. To develop conceptual understanding of alpine talus and determine its storage capacity and hydraulic properties, we investigated a talus unit in the Lake O'Hara watershed in the Canadian Rockies using ground‐penetrating radar, electrical resistivity tomography, measurements of talus discharge, tracer tests, and isotopic hydrograph separation. The study talus, consisting mainly of quartzite and carbonate rock fragments, had very high hydraulic conductivity (0·01–0·03 m s−1) and fast hydrograph recession (exponential decay coefficient of 1 d−1), suggesting that its storage capacity is limited to a time scale of less than a week. Groundwater flow through the talus occurs in a relatively thin (0·01–0·1 m) saturated zone at the base of the talus, which appears to have discrete flow paths rather than a single continuous sheet. A late‐lying snowpack, located at the top of the talus and cliff ledges above, sustains baseflow discharging from the talus, which provides moisture to alpine meadows downstream. Although this study indicates limited storage capacity of talus, further research is required to examine the storage and transmission characteristics of talus consisting of different types of geological materials or formed in different environments. Copyright © 2011 John Wiley & Sons, Ltd.
A heat pulse technique for the determination of small‐scale flow directions and flow velocities in the streambed of sand‐bed streams
Authors: Lewandowski Jörg , Angermann Lisa , Nützmann Gunnar , Fleckenstein Jan H.
Published: February 2011

The hyporheic zone (HZ) has the capability to eliminate and attenuate nutrients and contaminants in riverine systems. Biogeochemical reactions and the potential elimination of contaminants are strongly controlled by the flow paths and dynamics in the HZ. Nevertheless, an easily applicable method for the field determination of flow patterns in the HZ is still lacking. Therefore, a heat pulse technique, which traces the movement of a short heat pulse in the upper part of the HZ and other sand beds, was developed. Five rods are vertically driven into the sediment of the streambed; one rod with a heater as point source located in about 10‐cm sediment depth and four rods with four temperature sensors in 3 cm distance, arranged concentrically with 7 cm diameter around the heating rod. Subsequently, a heat pulse is applied and the resulting breakthrough curves are indicative of flow velocities and flow directions in the streambed. A rough data analysis procedure is also suggested. In addition, laboratory experiments were performed to test the heat pulse technique. These experiments were validated based on coupled numerical modelling of flow and heat transport. First field tests of the method prove that the method is easily applicable under field conditions. These first field tests showed highly complex flow patterns with flow velocities from 1·8 to 4·9 cm min−1and flow directions from parallel to surface flow to opposite to surface flow. This suggests the need for a robust method to quantify hyporheic flow patternsin situ. Copyright © 2011 John Wiley & Sons, Ltd.
Daz‐ and Pumilio‐like genes are asymmetrically localized in Pelophylax (Rana) oocytes and are expressed during early spermatogenesis
Authors: Marracci Silvia , Michelotti Valentina , Casola Claudio , Giacoma Cristina , Ragghianti Matilde
Published: February 2011

In many organisms, the specification of cell fate and the formation of embryonic axes depend on a proper distribution of maternal mRNAs during oogenesis. Asymmetrically localized determinants are required both for embryonic axes and germline determination in anuran amphibians. As a model system of these processes, we have used a species complex of the genus Pelophylax (Rana), characterized by a hybridogenetic reproduction that involves events of genome exclusion and endoreduplication during meiosis in both sexes. With the aim of characterizing the still largely unknown molecular events regulating Pelophylax gametogenesis, we have isolated in this animal model homologues of the deleted in AZoospermia‐like (DAZl) and pumilio gene families (named RlDazl and RlPum1, respectively), which encode posttranscriptional regulators. Expression pattern analysis of these genes showed that
RlDazl is exclusively expressed in gonadal tissues, whereas RlPum1 is expressed in both somatic tissues and gonads. In situ hybridization carried out on gonads revealed that the two transcripts were asymmetrically localized along the animal–vegetal (A–V) axis of oocytes. In particular, the
RlDazl transcript progressively collected to the vegetal pole during oogenesis, whereas the RlPum1 mRNA was preferentially enriched at the animal hemisphere. In adult testes, RlDazl and RlPum1 were expressed in specific phases of spermatogenetic divisions as shown by immunostaining with anti‐H3 phosphohistone antibody. Our results indicate that RlDazl and RlPum1 represent two early indicators of oocyte polarity in this hybridogenetic vertebrate model. Additionally, RlDazl share with vertebrate DAZ‐ like genes a germ cell‐specific expression pattern. J. Exp. Zool. (Mol. Dev. Evol.) 316:330–338, 2011. © 2011 Wiley‐Liss, Inc.
Combined effects of TNF‐α, IL‐1β, and HIF‐1α on MMP‐2 production in ACL fibroblasts under mechanical stretch: An in vitro study
Authors: Wang Yequan , Tang Zhenyu , Xue Ruyue , Singh Gurinder K. , Shi Kunning , Lv Yonggang , Yang Li
Published: February 2011

The dynamics between inflammatory factors, mechanical stress, and healing factors, in an intra‐articular joint, are very complex after injury. Injury to intra‐articular tissue [anterior cruciate ligament (ACL), synovium] results in hypoxia, accumulation of various pro‐inflammatory factors, cytokines, and metalloproteases. Although the presence of increased amounts of matrix‐metalloproteinases (MMP) in the joint fluid after knee injury is considered the key factor for ACL poor healing ability; however, the exact role of collective participants of the joint fluid on MMP‐2 activity and production has not been fully studied yet. To investigate the combined effects of mechanical injury, inflammation and hypoxia induced factor‐1α (HIF‐1α) on induction of MMP‐2; we mimicked the microenvironment of joint cavity after ACL injury. The results show that TNF‐α and IL‐1β elevate the activity of MMP‐2 in a dose‐ and time‐dependent manner. In addition, mechanical stretch further enhances the MMP‐2 protein levels with TNF‐α, IL‐1β, and their mixture. CoCl2‐induced HIF‐1α (100 and 500 µM) also increases the levels and activity of MMP‐2. Mechanical stretch has a strong additional effect on MMP‐2 production with HIF‐1α. Our results conclude that mechanical injury, HIF‐1α and inflammatory factors collectively induce increased MMP‐2 production in ACL fibroblasts, which was inhibited by NF‐κB pathway inhibitor (Bay‐11‐7082). © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29: 1008–1014, 2011
Sensitivity of the SF‐36 to PTSD symptom change in veterans
Authors: Shiner Brian , Watts Bradley V. , Pomerantz Andrew , Young‐Xu Yinong , Schnurr Paula P.
Published: February 2011

The authors examined the relationship between changes in symptoms of posttraumatic stress disorder (PTSD) and functioning as measured by the Medical Outcomes Study Short Form‐36 (SF‐36) among 167 veterans in a primary care clinic. Those who reported at least moderate baseline symptoms were categorized as better, unchanged, or worse at reassessment. The SF‐36 was used to examine concordance between change in functioning and symptoms. Veterans with reliable changes in symptoms of PTSD showed corresponding statistically significant changes in functioning across health domains. Moreover, these changes in functioning were clinically significant on several SF‐36 subscales and on one summary scale.
Assessment of soil erosion hazard in Kilie catchment, East Shoa, Ethiopia
Authors: Haile G. W. , Fetene M.
Published: February 2011

This paper reports on a field study conducted in Kilie catchment, East Shoa Zone, Ethiopia to assess the rate of soil erosion by employing a soil loss prediction model (Universal Soil Loss Equation) integrated with in remote sensing and geographical information systems (RS/GIS), environment and gully measurement techniques. The final soil erosion risk map was produced after multiplication of the six factors involved in the USLE and RS/GIS. Gully measurement showed that the erosion rate is higher for the upland areas than the lowlands due to inappropriate soil and water conservation measures, free grazing by animals and conversion of hillside areas into farmlands. About 97·04 per cent of the study catchment falls within a range of 0–10 t ha−1 yr−1 sheet/rill erosion rate. We found that 2·17 per cent of the study area in the uplands has a soil erosion rate falling between 10 and 20 t ha−1 yr−1. About 0·8 per cent of the study area in the uplands is hit by severe sheet/rill erosion rate within the range of 20–60 t ha−1 yr−1. Gully erosion extent in the study area was evaluated through gully measurement and quantification methods. Gully density of 67 m ha−1 was recorded in the catchment. The gully to plot area ratio was found to be 0·14 on average. Hence, in the upland areas, sustainable land management practices are required in order to reduce the rate of soil erosion. Copyright © 2011 John Wiley & Sons, Ltd.
Binding of polynucleotides with single‐walled carbon nanotubes: Effect of temperature
Authors: Gladchenko G.O. , Lytvyn O.S. , Karachevtsev M.V. , Valeev V.A. , Leontiev V.S. , Karachevtsev V.A.
Published: February 2011

The effect of the change of the temperature (in the range from 20°C to 90°C) on the light absorption intensity of water suspensions of nanohybrids formed with single‐walled carbon nanotubes (SWNT) and single‐stranded polyriboadenylic acids, poly(rA), and polyribocytidylic acids, poly(rC), was studied. Different degrees of the polymer coating of nanotube surfaces were found by atomic force microscopy (AFM). According to UV‐vis absorption spectroscopy data, homopolymer adsorption onto the nanotube is followed with changes in optical characteristics of both, the polymer and SWNT, as a result of ππ‐stacking interaction of the polymer with the tube surface. Upon poly(rA) wrapping on the nanotubes, a significant part of its bases keeps self‐stacking while upon adsorption of the more rigid poly(rC), it is almost completely disordered. Spectroscopic data can be explained by a polymer re‐orientation on the nanotube with the heating that provides the optimal ππ‐stacking of nitrogen bases with the carbon surface. The increase of the temperature up to 90°C does not result in the polymer slipping off the nanotube and in a noticeable nanotube precipitation.
Interaction of Ag‐free and Ag‐Doped hydroxyapatite with Ciprofloxacin solutions
Authors: Ivashchenko O. A. , Perekos A. O. , Ulianchych N. V. , Uvarova I. V. , Protsenko L. S. , Budylina O. M. , Holovkova M. Y. , Yarmola T. M.
Published: February 2011

The processes occurring during the interaction of Ag‐free and Ag‐doped hydroxyapatite with ciprofloxacin solutions have been investigated. Particular attention was paid to the formation of a gel due to the interaction of hydroxyapatite with water/ciprofloxacin solutions. The examination of the surface morphology of the gel revealed the transformation of the morphology of both samples. The investigation of the adsorptivity of the Ag‐free and Ag‐doped hydroxyapatite towards ciprofloxacin showed a significant difference. The introduction of silver ions into the hydroxyapatite structure sharply reduced its adsorptivity towards ciprofloxacin. Neither new phases nor changes in the interplane spacing were observed in the XRD patterns from Ag‐free and Ag‐doped hydroxyapatite composites with ciprofloxacin.
Expression of SNF1/AMP‐activated protein kinase and casein kinase‐1ε in different rat tissues are sensitive markers of in vivo silver nanoparticles action
Authors: Minchenko D.O. , Bozhko I.V. , Zinchenko T.O. , Yavorovsky O.P. , Minchenko O.H.
Published: February 2011

SNF1/AMP‐activated protein kinase (SNARK) is a member of AMPK kinases which are related to serine/threonine protein kinases. It is a molecular component of the cellular stress response. Casein kinase‐1ε is important molecular components of circadian clock system and plays a fundamental role in the metabolism at both the behavioral and molecular levels and potentially has great importance for understanding metabolic health and disease, because disturbance the circadian processes lead to developing of different pathology. We have shown that silver nanoparticles change the expression of SNARK and casein kinase‐1ε in rats in time‐dependent and tissue‐specific manner. The results of this study demonstrated that silver nanoparticles have significant effect on important regulatory mechanisms which control metabolic processes in different tissues via SNARK and casein kinase‐1ε gene expression and that these genes could be a sensitive test for detection of silver nanoparticles toxic action.
Characterization of the solid components of three desensitizing toothpastes and a mouth wash
Authors: Peetsch A. , Epple M.
Published: February 2011

The solid components of three toothpastes and a mouth wash which are intended to enhance the remineralization of teeth and occlusion of dentinal tubuli were isolated and analyzed. Samples of the toothpaste BioRepair®, the mouth wash BioRepair®, the toothpaste nanosensitive® hca, and the toothpaste Theramed® S.O.S. Sensitive were characterized by dynamic light scattering (DLS), nanoparticle tracking analysis (NTA), scanning electron microscopy (SEM), energy‐dispersive X‐ray spectroscopy (EDX), X‐ray powder diffraction (XRD), atomic absorption spectroscopy (AAS), thermogravimetric analysis (TG), and elemental analysis. All samples contained primary particles in the size range of 30–60 nm, that were all agglomerated in aqueous dispersion to particles in the size range of 200 to 400 nm. BioRepair® contained a zinc‐substituted hydroxyapatite and amorphous silica, nanosensitive®hca contained TiO2 (anatase) and an amorphous Na‐Ca‐Si‐P bioglass, and Theramed® S.O.S. Sensitive contained TiO2 (anatase), amorphous silica and traces of a calcium‐containing phase. The size of the mineral particles was in all cases suitable to fit into dentinal tubuli, especially after breaking up the agglomerated nanoparticles by mechanical forces, e. g. during tooth brushing.
Applied nano bio systems with microfluidics and biosensors for three‐dimensional cell culture
Authors: Schober A. , Fernekorn U. , Lübbers B. , Hampl J. , Weise F. , Schlingloff G. , Gebinoga M. , Worgull M. , Schneider Mark , Augspurger Caroline , Hildmann Christian , Kittler Mario , Donahue Mary
Published: February 2011

Applications of nanotechnology and microtechnology lead to a field which could be called nanosystems integration. The next step is the development of nanobiotechnological systems, which could reflect the hierarchical organization of biological systems that utilise scales and laws of nature on all metric scales. As one example of such systems we present the design and construction of a new class of micro bioreactors. It has been shown that 3D culture systems reveal the in vivo situation much better than the cultivation of 2D one cell type alone. For this purpose we have to construct and arrange fluidic devices and a cell‐biological environment in such a way, that living cells can survive in a three‐dimensional, organ‐like structure, enabled by technical devices. Such organ‐like cell structures may lead to new ways in medicinal chemistry for the determination of ADME/Tox (absorption‐distribution‐metabolism‐excretion and toxicity) properties of potential drugs. One part of the construction principle is the integration of sensors, preferable novel AlGaN/GaN nanosensors. The latter nanosensors offer the possibility to estimate reactions of cells attached to the sensor surface non‐destructively and label‐free. These sensors are highly sensitive and biocompatible to cells. Furthermore, they are transparent to enable microscopic and other optical observations of the cells. In an advanced version the sensor is to be integrated to give a better insight into cellular processes of the cells that are cultivated in such micro bioreactors.
Novel partitioned time integration methods for DAE systems based on L‐stable linearly implicit algorithms
Authors: Jia C. , Bursi O. S. , Bonelli A. , Wang Z.
Published: February 2011

Real‐time applications based on the principle of Dynamic Substructuring require integration methods that can deal with constraints without exceeding an a priori fixed number of steps. For these applications, first we introduce novel partitioned algorithms able to solve DAEs arising from transient structural dynamics. In particular, the spatial domain is partitioned into a set of disconnected subdomains and continuity conditions of acceleration at the interface are modeled using a dual Schur formulation. Interface equations along with subdomain equations lead to a system of DAEs for which both staggered and parallel procedures are developed. Moreover under the framework of projection methods, also a parallel partitioned method is conceived. The proposed partitioned algorithms enable a Rosenbrock‐based linearly implicit LSRT2 method, to be strongly coupled with different time steps in each subdomain. Thus, user‐defined algorithmic damping and subcycling strategies are allowed. Secondly, the paper presents the convergence analysis of the novel schemes for linear single‐Degree‐of‐Freedom (DoF) systems. The algorithms are generally A‐stable and preserve the accuracy order as the original monolithic method. Successively, these results are validated via simulations on single‐ and three‐DoFs systems. Finally, the insight gained from previous analyses is confirmed by means of numerical experiments on a coupled spring–pendulum system. Copyright © 2011 John Wiley & Sons, Ltd.
A large deformation frictional contact formulation using NURBS‐based isogeometric analysis
Authors: De Lorenzis L. , Temizer İ. , Wriggers P. , Zavarise G.
Published: February 2011

This paper focuses on the application of NURBS‐based isogeometric analysis to Coulomb frictional contact problems between deformable bodies, in the context of large deformations. A mortar‐based approach is presented to treat the contact constraints, whereby the discretization of the continuum is performed with arbitrary order NURBS, as well as C0‐continuous Lagrange polynomial elements for comparison purposes. The numerical examples show that the proposed contact formulation in conjunction with the NURBS discretization delivers accurate and robust predictions. Results of lower quality are obtained from the Lagrange discretization, as well as from a different contact formulation based on the enforcement of the contact constraints at every integration point on the contact surface. Copyright © 2011 John Wiley & Sons, Ltd.
Messen, was draußen los ist
Authors: Heerlein Jörg
Published: February 2011

Immer mehr Autos scannen ihre Umgebung ab, um kritische Situationen früh zu erkennen und den Fahrer entsprechend zu unterstützen. Die Unfallforscher der deutschen Versicherer schätzen, dass alleine durch automatische Notbremsassistenten zwölf Prozent aller schweren Pkw‐Unfälle verhindert werden könnten. Radar‐ oder laserbasierte Abstandsmesser sind wichtige Technologien für solche Anwendungen. Optische Systeme setzen hierbei überwiegend auf leistungsstarke, infrarote Pulslaserdioden mit sehr kurzen Schaltzeiten.
Die Krux mit dem Anschluss
Authors: Hentschel Konrad , Walter Annette
Published: February 2011

Bildverarbeitungssysteme finden in vielen Bereichen Anwendung, von der Automatisierungstechnik über die Medizintechnik bis hin zur Sicherheitstechnik. Diese Systeme bestehen meist aus einer Beleuchtungseinheit, einem abbildenden System, einer Bilderfassungseinheit und der Auswertesoftware. Zu Beginn wird die Anwendung definiert: Welches Objekt soll mit welcher Auflösung in welcher Umgebung abgebildet und analysiert werden. Daraufhin fällt die Entscheidung, welche Kamera Verwendung findet. Erst dann wird die passende Optik gesucht, wobei häufig Probleme auftreten.