bluuebunny/crossref_metadata_2025_split huggingface dataset:
Open Conversion after Endovascular Aortic Aneurysm Repair with the Ovation Prime™ Endograft
Authors: Georgiadis George S. , Charalampidis Dimitrios , Georgakarakos Efstratios I. , Antoniou George A. , Trellopoulos George , Vogiatzaki Theodosia , Lazarides Miltos K. 
Published: March 2014

Advances in abdominal aortic aneurysm (AAA) endograft device technology have contributed to improved outcomes and durability of endovascular aortic aneurysm repair (EVAR), even in complex infrarenal aortic anatomies. However, stent graft failure secondary to endoleaks, migration, endotension and sac enlargement are persistent problems that can result in aneurysm rupture following EVAR. A symptomatic infrarenal AAA (4mm proximal neck) was treated initially with an Ovation Prime™ device (TriVascular, Inc., Santa Rosa, CA) in an off-label fashion, leading to type Ia endoleak moderately reduced by additional proximal neck ballooning. A failed Chimney technique to the single patent, but severely stenosed, right renal artery preceded the use of this device. A large type Ia endoleak was evident at 6-month follow-up, but following a failed supplementary endovascular intervention with coils to seal the endoleak, the patient presented with hemorrhagic shock from AAA rupture, requiring urgent open conversion. Intraoperatively it was impossible to explant this new type of endograft. Circumferential tying of the infrarenal aorta with a Teflon band was unable to stop the bleeding. However, after dividing the body of the stent-graft below the two proximal polymer rings, the endoleak was successfully treated by suturing the graft with the proximal aortic neck. The procedure was completed with extension of the stump to the common femoral arteries using a bifurcated Dacron prosthesis. The body of an Ovation Prime™ endograft may be impossible to explant in open conversion conditions. Large prospective studies with longer follow-up are required to adequately reflect the behavior of this particular device.
A Comparative Evaluation between New Ternary Zirconium Alloys as Alternative Metals for Orthopedic and Dental Prosthetic Devices
Authors: Shyti Genti , Rosalbino Francesco , Macciò Daniele , Scarabelli Linda , Quarto Rodolfo , Giannoni Paolo 
Published: March 2014

Purpose We assessed in vitro the corrosion behavior and biocompatibility of four Zr-based alloys (Zr97.5 Nb1.5 VM1.0 ; VM, valve metal: Ti, Mo, W, Ta; at%) to be used as implant materials, comparing the results with grade-2 titanium, a biocompatible metal standard. Methods Corrosion resistance was investigated by open circuit potential and electrochemical impedance spectroscopy measurements as a function of exposure time to an artificial physiological environment (Ringer's solution). Human bone marrow stromal cells were used to evaluate biocompatibility of the alloys and their influence on growth kinetics and cell osteogenic differentiation through histochemical and gene expression analyses. Results Open circuit potential values indicated that Zr-based alloys and grade-2 Ti undergo spontaneous passivation in the simulated aggressive environment. High impedance values for all samples demonstrated improved corrosion resistance of the oxide film, with the best protection characteristics displayed by Zr97.5 Nb1.5 Ta1.0. Cells seeded on all surfaces showed the same growth kinetics, although matrix mineralization and alkaline phosphatase activity were maximal on Zr97.5 Nb1.5 Mo1.0 and Zr97.5 Nb1.5 Ta1.0. Markers of ongoing proliferation, however, such as podocalyxin and CD49f, were still overexpressed on Zr97.5 Nb1.5 Mo1.0 even upon osteoinduction. No relevant effects were noted for the CD146-expressing population of bone progenitors. Nonetheless, the presence of a more differentiated cell population on Zr97.5 Nb1.5 Ta1.0 samples was inferable by comparing mineralization data and transcript levels of osteogenic markers (osteocalcin, osteopontin, bone sialoprotein, and RUNX2). Conclusions The combination of passivation, corrosion resistance and satisfactory biotolerance to bone progenitors make the Zr-based alloys promising implant materials. Among those we tested, Zr97.5 Nb1.5 Ta1.0 seems to be the most appealing.
Role of Vasodilation during Normothermic Machine Perfusion of DCD Porcine Livers
Authors: Nassar Ahmed , Liu Qiang , Farias Kevin , D'Amico Giuseppe , Buccini Laura , Urcuyo Daniel , Kelly Dympna , Hashimoto Koji , Eghtesad Bijan , Uso Teresa Diago , Miller Charles , Quintini Cristiano 
Published: March 2014

Introduction Normothermic machine perfusion (NMP) of the liver is a promising preservation modality that holds the potential to better preserve and even repair marginal grafts. In spite of several literature studies showing the benefits of NMP over cold storage, there is paucity of data regarding the mechanisms involved in the optimization of the microcirculation during preservation of these organs. We present our data on the impact of different vasodilators on DCD porcine livers preserved with NMP. Materials and methods Livers from 15 female Yorkshire pigs (30-40 kg) were subjected to 60 min of WIT followed by 10 h of NMP. Group PC (n = 5) received a prostacyclin analog (epoprostenol sodium) and the AD group (n = 5) received adenosine, whereas group WV (n = 5) was perfused without using any vasodilator. Liver function was assessed by measuring, liver enzyme levels, bile production rate, and histological analysis. Results At the end of perfusion, the PC group showed significantly lower AST (583 ± 62 vs. 2471 ± 745 and 2547 ± 690 IU/dl), ALT (41 ± 3 vs. 143 ± 28 and 111 ± 25 IU/dl) and LDH (840 ± 85 vs. 2756 ± 408 and 4153 ± 1569 IU/dl) levels compared to the AD and WV groups respectively (p<0.05). Bile production was significantly higher in the PC group compared to the AD group and WV, respectively (95 ± 9 vs. 37 ± 10 and 45 ± 18ml) (p<0.05). Histological samples of the PC group showed preserved hepatic architecture while those of the AD group and WV showed sinusoidal dilatation, architectural distortion, and profuse intraparenchymal hemorrhage. Conclusions Maintenance of optimal microcirculatory homeostasis using proper vasodilators is a key factor in NMP of DCD livers.
The Impact of Technology in Mathematics Education: A Case Study of Pakistan
Authors: M. Arif Hussain  , Mujeeb  Ahmed  Khan  , Shaheen  Abbas,  M.  Ilyas and  Bulbul  Jan  , M. Rashid Kamal Ansari  
Published: March 2014

As we know that computers have become fountain pens of twenty first century. This paper discusses Computer Algebra System (CAS)activities used as part of a study conducted by the authors using Mathematica. It also emphasizes the use of Matlab for students and researchers for the purpose of verification of results of the problems at hand. This study will attempt to show the positive effect of the use of technology on students’ motivation by taking three examples from calculus, advanced algebra and sequence and series problems. The graphic illustration of functions helps students towards a proper understanding of mathematical science problems. The work carried out will be useful for students, researchers, and teachers understand both theory and use of computer applications in order to become master of the subject.
Exploring Organizational Culture Dimensions in a Lake-Based Eco-Tourism Resort
Authors: Yusof Nor’Aini , Che Jamil Mohd Fitri 
Published: March 2014

AbstractEcotourism has been identified as one of the main attractions in the promotion of tourism in Malaysia. Despite having a number of breath-taking lakes, most of the well known ecotourism resorts are located in coastal-based areas. Less attention is given to the lake-based ecotourism resorts, causing concern about the neglect of management issues which have led to a low occupancy rate. Meanwhile, scholars believe that organizational culture is an important factor in effective management. However, there is a lack of studies on the management of resorts, especially concerning organizational culture. The aim of this paper is to explore the organizational culture of ecotourism resorts in an ecotourism area; Tasik Kenyir. Questionnaires were distributed to resort employees who have agreed to participate in the survey, yielding a 77% response rate. The data was analysed using factor analysis. Four factors have emerged as constructs of organizational values and another five factors emerged for organizational practice. The results provide an understanding of the organizational culture that is available in resorts in the ecotourism industry.
Personalised Travel Services: an Exploratory Study in Singapore Context
Authors: Singh Bhati Abhishek , Tack Hoong Cheong , Lian Fong Jaclyn Chang , Kaur Kanwaljit 
Published: March 2014

AbstractThe aims of the study were to explore the demand for personalised travel services within the affluent customer segment of the outbound travelers in Singapore. The study uncovers the desired service attributes of same consumer segment. The paper begins with a general and broad overview of the travel and tourism industry worldwide and in the Asia Pacific region specifically in Singapore. The international tourism and hospitality sector has grown rapidly over the last ten years and according to the United Nations World Tourism Organisation (UNWTO), international tourist arrivals in 2012 grew to 980 million. Similarly, there has been an increase in outbound travels in Singapore. This growth has been fuelled by the economic growth that Singapore has experienced over the years. The study surveys the current literature to provide data to show the growth of outbound travel from Singapore and the increasing number of affluent Singapore travelers. The study considers an email questionnaire survey to gauge the travel patterns and desires of the affluent traveler market in Singapore. The exploratory findings identify a market for personalized travel services in Singapore and consider an inventory of service attributes desired by the affluent customer segment in Singapore. More specifically, the findings indicate that almost 65% of respondents preferred personal travel services (PTS) with 70% who currently book tours through travel agents indicating their preference for PTS. What was particularly interesting was that over 60% of those who currently engage in self-booking found the idea of PTS appealing. The key draws of PTS are convenience, personalization of itinerary and tour package, experience of consultants and trust. Personalised travel services are targeted to the high income market and the potential demand for PTS among travelers who undertake two or more trips a year was about 72%. Travelers today are looking for more value-added services and interesting tour packages rather than the run of the mill mass tours that many travel agents still provide. Growing affluence and the desire for unique and unusual tours is creating a niche market for travel agencies to exploit. The current and common business model of providing mass tours where customers are herded on a standard itinerary does not sit well with the well-heeled and sophisticated traveler of today. Today’s affluent travelers want to be treated not as mere customers but rather as valuable clients, partnering with the tour agency to create unparalleled and enriching tour experiences.
Seasonal evapotranspiration patterns in mangrove forests
Authors: Barr Jordan G. , DeLonge Marcia S. , Fuentes Jose D. 
Published: March 2014

AbstractDiurnal and seasonal controls on water vapor fluxes were investigated in a subtropical mangrove forest in Everglades National Park, Florida. Energy partitioning between sensible and latent heat fluxes was highly variable during the 2004–2005 study period. During the dry season, the mangrove forest behaved akin to a semiarid ecosystem as most of the available energy was partitioned into sensible heat, which gave Bowen ratio values exceeding 1.0 and minimum latent heat fluxes of 5 MJ d−1. In contrast, during the wet season the mangrove forest acted as a well‐watered, broadleaved deciduous forest, with Bowen ratio values of 0.25 and latent heat fluxes reaching 18 MJ d−1. During the dry season, high salinity levels (> 30 parts per thousand, ppt) caused evapotranspiration to decline and correspondingly resulted in reduced canopy conductance. From multiple linear regression, daily average canopy conductance to water vapor declined with increasing salinity, vapor pressure deficit, and daily sums of solar irradiance but increased with air temperature and friction velocity. Using these relationships, appropriately modified Penman‐Monteith and Priestley‐Taylor models reliably reproduced seasonal trends in daily evapotranspiration. Such numerical models, using site‐specific parameters, are crucial for constructing seasonal water budgets, constraining hydrological models, and driving regional climate models over mangrove forests.
Reversible functional connectivity disturbances during transient global amnesia
Authors: Peer Michael , Nitzan Mor , Goldberg Ilan , Katz Judith , Gomori J. Moshe , Ben‐Hur Tamir , Arzy Shahar 
Published: March 2014

ObjectiveTransient global amnesia (TGA), an abrupt occurrence of severe anterograde episodic amnesia accompanied by repetitive questioning, has been known for more than 50 years. Despite extensive research, there is no clear evidence for the underlying pathophysiological basis of TGA. Moreover, there is no neuroimaging method to evaluate TGA in real time.MethodsHere we used resting‐state functional magnetic resonance imaging recorded in 12 patients during the acute phase of TGA together with connectivity and cluster analyses to detect changes in the episodic memory network in TGA.ResultsOur results show a significant reduction in functional connectivity of the episodic memory network during TGA, which is more pronounced in the hyperacute phase than in the postacute phase. This disturbance is bilateral, and reversible after recovery. Although the hippocampus and its connections are significantly impaired, other parts of the episodic memory network are also impaired. Similar results were obtained for the analysis of the episodic memory network whether it was defined in a data‐driven or literature‐based manner.InterpretationThese results suggest that TGA is related to a functional disturbance in the episodic memory network, and supply a neuroimaging correlate of TGA during the acute phase. Ann Neurol 2014;75:634–643
Storage of Electrical Information in Metal–Organic‐Framework Memristors
Authors: Yoon Seok Min , Warren Scott C. , Grzybowski Bartosz A. 
Published: March 2014

AbstractSingle crystals of a cyclodextrin‐based metal–organic framework (MOF) infused with an ionic electrolyte and flanked by silver electrodes act as memristors. They can be electrically switched between low and high conductivity states that persist even in the absence of an applied voltage. In this way, these small blocks of nanoporous sugar function as a non‐volatile RRAM memory elements that can be repeatedly read, erased, and re‐written. These properties derive from ionic current within the MOF and the deposition of nanometer‐thin passivating layers at the anode flanking the MOF crystal. The observed phenomena are crucially dependent on the sub‐nanometer widths of the channels in the MOF, allowing the passage of only smaller ions. Conversely, with the electrolyte present but no MOF, there are no memristance or memory effects.
A Simple 3,4‐Ethylenedioxythiophene Based Hole‐Transporting Material for Perovskite Solar Cells
Authors: Li Hairong , Fu Kunwu , Hagfeldt Anders , Grätzel Michael , Mhaisalkar Subodh G. , Grimsdale Andrew C. 
Published: March 2014

AbstractWe report a novel electron‐rich molecule based on 3,4‐ethylenedioxythiophene (H101). When used as the hole‐transporting layer in a perovskite‐based solar cell, the power‐conversion efficiency reached 13.8 % under AM 1.5G solar simulation. This result is comparable with that obtained using the well‐known hole transporting material 2,2′,7,7′‐tetrakis(N,N‐di‐p‐methoxyphenylamine)‐9,9′‐spirobifluorene (spiro‐OMeTAD). This is the first heterocycle‐containing material achieving >10 % efficiency in such devices, and has great potential to replace the expensive spiro‐OMeTAD given its much simpler and cheaper synthesis.
The combined effect of additives and processing on the thermal stability and controlled release of essential oils in antimicrobial films
Authors: Efrati Roni , Natan Michal , Pelah Avishay , Haberer Anina , Banin Ehud , Dotan Ana , Ophir Amos 
Published: March 2014

ABSTRACTEssential oils (EOs) have a long history as food preservatives and many advantages compared to synthetic preservatives. The major limitation of EOs as antimicrobial agents incorporated into a polymeric matrix is their low thermal stability and their high volatility from polymers. This study suggests a new methodology approach to bypass the key limitations of adding EOs into active packaging, as food preservatives. Antimicrobial active films based on linear low density polyethylene (LLDPE) and Montmorillonite (MMT) were produced by incorporating the EO thymol in a stepwise procedure. The production of the film composites, containing thymol, has been conducted, under a protocol of three stages: (1) production of a highly porous nano composite master batch; (2) impregnation of thymol into the master batch; and (3) cast film extrusion. Adding MMT incorporated together with a foaming agent at stage‐(1) increased significantly the heat stability of the EO during melt processing at stage‐(3). Finally, the film obtained showed a high antimicrobial activity. The results obtained have proven the synergistic interaction between MMT, foaming agent and thymol. As the MMT content in the film increased, the loss of EO in the processing decreased, leading to a natural antimicrobial film with improved antibacterial properties. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40564.
Effects of peroxide and gamma radiation on properties of devulcanized rubber/polypropylene/ethylene propylene diene monomer formulation
Authors: Hassan Medhat M. , Badway Nagwa A. , Elnaggar Mona Y. , Hegazy El‐Sayed A. 
Published: March 2014

ABSTRACTMechanical and thermal properties of devulcanized rubber (DR)/polypropylene (PP)/ethylene propylene diene monomer blends (EPDM) were studied at various concentrations of dicumyl peroxide (DCP) and gamma radiation doses. The blends showed improved mechanical properties for vulcanized sample. The coupling of DR/PP/EPDM with different proportions of DCP was investigated by X‐ray diffraction and scanning electron microscopy techniques. Evaluation of the developed blends, unirradiated and gamma irradiated, was carried out using elastic modulus, tensile strength, elongation at break, thermogravimetric analysis, kinetic analysis, and DSC measurements. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40611.
Preparation and functional evaluation of agarose derivatives
Authors: Chaudhary Jai Prakash , Kondaveeti Stalin , Gupta Vishal , Prasad Kamalesh , Meena Ramavatar 
Published: March 2014

ABSTRACTA facile microwave‐assisted one‐pot synthesis of sodium carboxymethylagarose and calcium carboxymethylagarose from Gracilaria dura agarose (Ag) has been described. The process is user friendly, and the highest degree of substitution was obtained within 15 min compared with the conventional method, which requires more than 3 h. Solubility and gelling behavior of the modified Ag products were found to be dependent on degree of substitution of the products. The characterizations were done by using Fourier transform infrared spectroscopy, 1H‐ and 13C‐nuclear magnetic resonance spectroscopy, thermogravimetric analysis, scanning electron microscopy, Inductively coupled plasma spectrophotometry (ICP), rheology, conductometer analysis, and DNA gel electrophoresis. These agarose derivatives were easily soluble in water and exhibited low thermal hysteresis, improved conductivity, and improved the DNA resolution ability of the parent G. dura Ag hydrogels. These hydrogels may have potential applications in the areas including electrochemical devices, microbiology, biomedical, and pharmaceuticals fields. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40630.
Investigating Construction History, Labour Investment and Social Change at Ocmulgee National Monument's Mound A, Georgia, USA, Using Ground‐penetrating Radar
Authors: Bigman Daniel P. , Lanzarone Peter M. 
Published: March 2014

ABSTRACTPrehistoric societies from around the world constructed monumental mounded architecture (earthen pyramids) for a variety of functions, including the foundation for temples or a leader's residence, community stages and cemeteries. Flat‐topped earthen mounds often have complicated histories where the function, size, orientation and summit architecture varied throughout time. This paper presents the results from a ground‐penetrating radar (GPR) survey conducted on the summit of Mound A, the largest prehistoric Native American mound at Ocmulgee National Monument located in central Georgia, USA. Our study indicates that performing depth‐slice analyses of flat‐topped mounds can effectively map successive construction stages over distinct periods of archaeological prehistory. The GPR data show distinctive low‐amplitude, discontinuous stratigraphic variations that we interpret to be related to mound fill, which are interrupted by high‐amplitude coherent summit reflections. We also maintain sufficient vertical and horizontal resolution to identify summit architecture on earlier mound‐use episodes, which is imaged by distinct reflection geometry as patterned linear, square and circular high‐amplitude events in GPR depth‐slices. The authors recorded four possible mound summits, the western expansion of the mound, and the shifting location and shape of summit architecture; in addition to resolving a discrepancy regarding the location of early excavation units from the 1930s. Shallow geophysical data indicate a decline in the volume of material used over the course of mound construction, and by inference, a decline in the size of the labour force used to construct each stage. We conclude that the power and influence of Ocmulgee's early leadership subsided over the course of Mound A's use, and may have been contested by an emerging faction. Copyright © 2014 John Wiley & Sons, Ltd.