bluuebunny/crossref_metadata_2025 huggingface dataset:
Long-term volcanic hazard assessment on El Hierro (Canary Islands)
Authors: Becerril L. , Bartolini S. , Sobradelo R. , Martí J. , Morales J. M. , Galindo I.
Published: February 2014

Abstract. Long-term hazard assessment, one of the bastions of risk-mitigation programs, is required for territorial planning and for developing emergency plans. To ensure qualitative and representative results, long-term volcanic hazard assessment requires several sequential steps to be completed, which include the compilation of geological and volcanological information, the characterization of past eruptions, spatial and temporal probabilistic studies, and the simulation of different eruptive scenarios. Despite being a densely populated active volcanic region that receives millions of visitors per year, no systematic hazard assessment has ever been conducted in the Canary Islands. In this paper we focus our attention on El Hierro, the youngest of the Canary Islands and the most recently affected by an eruption. We analyze the past eruptive activity (how), the spatial probability (where) and the temporal probability (when) of an eruption on the island. By studying the past eruptive behavior of the island and assuming that future eruptive patterns will be similar, we aim to identify the most likely volcanic scenarios and corresponding hazards, which include lava flows, pyroclastic fallout and pyroclastic density currents (PDCs). Finally, we estimate their probability of occurrence. The end result is the first total qualitative volcanic hazard map of the island.
Synchronization of coupled stick-slip oscillators
Authors: Sugiura N. , Hori T. , Kawamura Y.
Published: February 2014

Abstract. A rationale is provided for the emergence of synchronization in a system of coupled oscillators in a stick-slip motion. The single oscillator has a limit cycle in a region of the state space for each parameter set beyond the supercritical Hopf bifurcation. The two-oscillator system that has similar weakly coupled oscillators exhibits synchronization in a parameter range. The synchronization has an anti-phase nature for an identical pair. However, it tends to be more in-phase for a non-identical pair with a rather weak coupling. A system of three identical oscillators (1, 2, and 3) coupled in a line (with two springs k12=k23) exhibits synchronization with two of them (1 and 2 or 2 and 3) being nearly in-phase. These collective behaviours are systematically estimated using the phase reduction method.
Crop residue decomposition in Minnesota biochar amended plots
Authors: Weyers S. L. , Spokas K. A.
Published: February 2014

Abstract. Impacts of biochar application at laboratory scales are routinely studied, but impacts of biochar application on decomposition of crop residues at field scales have not been widely addressed. The priming or hindrance of crop residue decomposition could have a cascading impact on soil processes, particularly those influencing nutrient availability. Our objectives were to evaluate biochar effects on field decomposition of crop residue, using plots that were amended with biochars made from different feedstocks and pyrolysis platforms prior to the start of this study. Litterbags containing wheat straw material were buried below the soil surface in a continuous-corn cropped field in plots that had received one of seven different biochar amendments or a non-charred wood pellet amendment 2.5 yr prior to start of this study. Litterbags were collected over the course of 14 weeks. Microbial biomass was assessed in treatment plots the previous fall. Though first-order decomposition rate constants were positively correlated to microbial biomass, neither parameter was statistically affected by biochar or wood-pellet treatments. The findings indicated only a residual of potentially positive and negative initial impacts of biochars on residue decomposition, which fit in line with established feedstock and pyrolysis influences. Though no significant impacts were observed with field-weathered biochars, effective soil management may yet have to account for repeat applications of biochar.
Europeizace a zahraniční politika: prostor pro další výzkum
Authors: Weiss Tomáš
Published: February 2014

This paper aims to review the existing debate on the relations between national and European levels in the EU and identify existing gaps. It aims at showing the current compartelization of the academic debate and suggesting a possible remedy. It discusses the current trends in Europeanization studies and shows that one of the dimensions (bottom-up) remains understudied. Similarly, the concept has been applied in the area of foreign policy in a very limited way to the detriment of our understanding of reality. Following these findings, the article suggests, firstly, that the relationship between the adjustment to European integration and the ability to pursue one's interest should be studied, both in terms of form and results, and, secondly, that foreign policy should be included in this research framework.
Opoziční smlouvy „za kopečky“ II.: Byl pakt ČSSD a ODS z let 1998-2002 demokratickou deviací?
Authors: Kopeček Lubomír
Published: February 2014

This is the second part of a two–part paper, the first one having been published in the previous volume of this journal. After the 1998 general elections to the Chamber of Deputies of the Czech Republic, the largest party, the Social Democratic Party (ČSSD), formed a minority government. The origin and existence of this government was enabled by an agreement with the second largest formation, the Civic Democratic Party (ODS). What was then known as the Opposition Agreement became the subject of considerable debate. The first part of the paper provided analysis of government practice in similar circumstances in Denmark, Sweden, New Zealand, and Italy at the time of the Historic Compromise. Here I focus specifically on the Czech case. The present paper points out not only the Opposition Agreement between the Social Democrats and the Civic Democratic Party and the later Toleration Patent, which even deepened the cooperation between these two parties, but also the frequent ad hoc legislative coalitions which the minority government was able to form.
The Public and Geoengineering Decision-Making
Authors: Wong Pak-Hang ,   Philosophy Documentation Center
Published: February 2014

In response to the Royal Society report’s claim that “the acceptability of geo­engineering will be determined as much by social, legal, and political issues as by scientific and technical factors” (Geoengineering the Climate: Science, Governance and Uncertainty [London: Royal Society, 2009], ix), a number of authors have suggested the key to this challenge is to engage the public in geoengineering decision-making. In effect, some have argued that inclusion of the public in geoengineering decision-making is necessary for any geoengineering project to be morally permissible. Yet, while public engagement on geoengineering comes in various forms, the discussion in geoengineering governance and the ethics of geoengineering have too often conceptualized it exclusively in terms of public participation in decision-making, and supported it by various liberal democratic values. However, if the predominant understanding of public engagement on—or, the role of the public in—geoengineering decision-making is indeed only grounded on liberal democratic values, then its normative relevance could be challenged by and in other ethical-political traditions that do not share those values. In this paper, I shall explore these questions from a Confucian perspective. I argue that the liberal democratic values invoked in support of the normative importance of public participation are, at least, foreign to Confucian political philosophy. This presents a prima facie challenge to view public participation in geoengineering decision-making as a universal moral requirement, and invites us to reconsider the normative significance of this form of public engagement in Confucian societies. Yet, I contend that the role of the public remains normatively significant in geoengineering governance and the ethics of geoengineering from a Confucian perspective. Drawing from recent work on Confucian political philosophy, I illustrate the potential normative foundation for public engagement on geoengineering decision-making.
Pipe Bursting Helps City Meet Current and Future Needs
Authors: Ambler Edward Alan
Published: February 2014

An ongoing program to replace worn‐out asbestos‐cement pipe with prechlorinated high‐density polyethylene (HDPE) pipe is helping the city of Casselberry, Fla., save water and money and protect the environment and its citizens.
Oriented crystallization of carbon by heating of an amorphous C–Co mixture film
Authors: Suzuki Hitoshi , Miura Yoshiro , Kumamoto Akihito , Nishioka Masateru , Abe Rui , Onagawa Jun , Kaito Chihiro
Published: February 2014

Fcc-Co nanoparticles and c-oriented graphite crystallites were grown on a Co–C mixture film heated in a transmission electron microscope (TEM) at 600 °C. The c-oriented graphite grew on the boundary between the Co nanoparticles and the film by the dissolution and precipitation of C atoms. The c-orientation of the graphite crystallites was identified from dark images and a high-resolution TEM image taken at a fold in the film. Upon heating to 800 °C, the Co nanoparticles changed their morphology, moved, and separated on the film. Many tracklike marks and unoriented graphite crystallites appeared on the film. Since dissolution and precipitation were induced, graphite crystallites grew on the sidewall of the Co nanoparticles.
Impact of overshoot current on set operation of atom switch
Authors: Sakamoto Toshitsugu , Tada Munehiro , Miyamura Makoto , Banno Naoki , Okamoto Koichi , Iguchi Noriyuki , Hada Hiromitsu
Published: February 2014

Current overshoot during a set operation has significant impacts on the ON conductance and reliability of resistive change devices such as atom switches. We break the set operation into three steps: incubation, transition, and settling. We clarify their contributions to the determinations of the ON conductance of the atom switch. The variation in the transition time causes a significant variation in the ON conductance. On the basis of the ON conductance distribution, the median of the transition time of 1 ns and its distribution are revealed.
High-performance dual-layer channel indium gallium zinc oxide thin-film transistors fabricated in different oxygen contents at low temperature
Authors: Tian Yu , Han Dedong , Zhang Suoming , Huang Fuqing , Shan Dongfang , Cong Yingying , Cai Jian , Wang Liangliang , Zhang Shengdong , Zhang Xing , Wang Yi
Published: February 2014

In this work, fully transparent dual-layer channel amorphous indium gallium zinc oxide thin-film transistors (a-IGZO TFTs) are fabricated on glass substrates at low temperature. Dual-layer channel a-IGZO TFTs are studied by changing the partial pressure of oxygen while sputtering IGZO layers for comparison with single-layer channel TFTs which are fabricated with a constant oxygen content. All four types of dual-layer channel TFT sample demonstrate better performance, on-to-off ratios of ∼108 and low subthreshold swing (SS) of less than 200 mV/decade, than the single-layer ones. TFTs with two layers, a low-oxygen layer and a high-oxygen layer formed using oxygen partial pressures of 0.01 and 0.05 Pa, respectively demonstrate relatively better performance with a mobility of more than 60 cm2 V−1 s−1. Among them, the TFTs with a channel layer thickness ratio of 3 : 1 show the best transfer characteristics with a high on-to-off current ratio (I
on/off) of 1.8 × 108 and a low SS of 135 mV/decade.
Nitridation of zinc oxide film by pulse mode rapid thermal annealing
Authors: Lin Chiung-Wei , Ho Po-Chi , Chang Shi-Jay , Chen Wen-Wei
Published: February 2014

In this study, pulse-mode rapid thermal annealing was used to nitridize zinc oxide film. It was found that the nitridation can introduce many nitrogen atoms into the processed film and form chemical bonds with zinc oxide. The electrical measurements verified that the majority carrier within the nitrided film is the hole. Besides, the nitridation process improved the crystalline structure of the processed film so that the nitrided zinc oxide showed high optical transmittance within the visible wavelength region. The carrier concentration, mobility, and resistivity of nitrided zinc oxide were 1.39 × 1016 cm−3, 9.5 cm2 V−1 s−1, and 47.45 Ω cm, respectively. This pulse-mode rapid thermal nitridation is an alternative method to obtain stable p-type zinc oxide film.
Open circuit voltage decay characteristics of 4H-SiC p–i–n diode with carbon implantation
Authors: Tanaka Atsushi , Nakayama Koji , Asano Katsunori , Miyazawa Tetsuya , Tsuchida Hidekazu
Published: February 2014

The open circuit voltage decay (OCVD) characteristics of 4H-SiC p–i–n diodes fabricated with the carbon implantation process are investigated. The bulk carrier lifetime in the fabricated devices can be estimated using OCVD measurements. The carrier lifetime at a high injection level (τHL) of the fabricated diode with carbon implantation is 10.5 µs, which is extremely long as compared with that of a diode fabricated with the standard process (1.3 µs).
Dual Band Gap Coupled Antenna Design with DGS for Wireless Communications
Authors: Kandwal A. , Sharma R. , Khah S. K.
Published: February 2014

A novel gap coupled dual band multiple ring antenna with a defected ground structure (DGS) has been successfully implemented. A different technique is used in this communication where both gap coupling and defected ground are applied to obtain better results for wireless applications. The designed antenna operates in two different frequency bands. The antenna shows a wideband in C-band and also resonates in the X-band. The main parameters like return loss, impedance bandwidth, radiation pattern and gain are presented and discussed. The gain is increased and the side lobe level is considerably reduced to a good extent. Designed antenna is tested and the results show that the simulation and experimental results are in good agreement with each other.
Sister Mary Joseph Nodule
Authors: Wroński Marek , Kluciński Andrzej , Krasnodębski Ireneusz W.
Published: February 2014

A Sister Mary Joseph nodule represents a cutaneous metastasis into the umbilicus. This clinical sign of intra‐abdominal malignancy is frequently overlooked or misinterpreted by both patients and their physicians. We report 4 patients with a Sister Mary Joseph nodule. The umbilical metastases appeared sonographically as hypoechoic masses with irregular margins and small internal hyperechoic foci. Further evaluation revealed disseminated malignancy, and the umbilical nodule was just “a tip of an iceberg.”
Are Knee Biomechanics Different in Those With and Without Patellofemoral Osteoarthritis After Anterior Cruciate Ligament Reconstruction?
Authors: Culvenor Adam G. , Schache Anthony G. , Vicenzino Bill , Pandy Marcus G. , Collins Natalie J. , Cook Jill L. , Crossley Kay M.
Published: February 2014

Objective

Patellofemoral (PF) osteoarthritis (OA) is prevalent following anterior cruciate ligament reconstruction (ACLR). This study aimed to investigate differences in transverse plane rotation between knees with varus and valgus alignment during gait in people with and without PFOA after ACLR.

Methods

Thirty‐six individuals who were mean ± SD 9 ± 2 years post‐ACLR (18 radiographic PFOA and 18 no knee OA) participated in this cross‐sectional study. Knee internal‐external rotation angles were measured using a 3‐dimensional motion analysis system during walking and running. Weight‐bearing frontal plane knee alignment, measured with an inclinometer, was used to classify participants as having varus or valgus alignment. Two‐way analysis of covariance was used to assess the effect of both PFOA and frontal plane knee alignment on dynamic knee internal‐external rotation.

Results

Significant interactions were found between PFOA status and frontal plane alignment on knee internal‐external rotation angles during walking (P = 0.019) and running (P = 0.002). Tests of simple effects revealed that during walking, individuals with valgus alignment and PFOA demonstrated a mean 3.9° (95% confidence interval [95% CI] 0.7, 7.1) less knee internal rotation than those with valgus alignment and no OA. During running this difference increased to 6.1° (95% CI 1.8, 10.4). For individuals with varus alignment, no significant effects were observed.

Conclusion

Less knee internal rotation during gait was found in individuals with PFOA and valgus alignment. A rotational shift of this magnitude may be sufficient to initiate or accelerate patellofemoral cartilage degeneration. Prospective studies are required to determine if these altered kinematic patterns result from, or contribute to, PFOA development after reconstruction.
From Metastable Colloidal Crystalline Arrays to Fast Responsive Mechanochromic Photonic Gels: An Organic Gel for Deformation‐Based Display Panels
Authors: Yang Dongpeng , Ye Siyun , Ge Jianping
Published: February 2014

An efficient and straightforward method is developed to prepare a mechanochromic photonic gel by fixing the metastable SiO2 colloidal crystalline array (CCA) in the mixture of ethylene glycol (EG) and poly(ethylene glycol) methacrylate (PEGMA) through photopolymerization. Thanks to the recent fabrication of solvent‐wrapped, metastable CCA, a high volume fraction of EG (46%) is introduced to the photonic gel before particle assembly, but not by swelling after polymerization, which leads to a more deformable composite than most reported opal gels. Compared to traditional photonic gels, this opal gel not only has improved mechanochromic sensitivity to weak external force and extended color tuning range from red to blue (Δλ = 150 nm), but also possesses fast and reversible response in millisecond level (20–200 ms), repeatable reflection signals in cycling and fatigue tests, and good resolution in response to localized deformation, which renders it an ideal deformation‐based photonic display screen. A new trigger system is designed to solve the large deformation causing color fading in conventional mechanochromic gels and brilliant red, green, and blue (RGB) pixels can be conveniently manipulated by ‘pushing’ operations.
Controlling Biological Activity with Light: Diarylethene‐Containing Cyclic Peptidomimetics
Authors: Babii Oleg , Afonin Sergii , Berditsch Marina , Reiβer Sabine , Mykhailiuk Pavel K. , Kubyshkin Vladimir S. , Steinbrecher Thomas , Ulrich Anne S. , Komarov Igor V.
Published: February 2014

Photobiological processes in nature are usually triggered by nonpeptidic chromophores or by modified side chains. A system is presented in which the polypeptide backbone itself can be conformationally switched by light. An amino acid analogue was designed and synthesized based on a reversibly photoisomerizable diarylethene scaffold. This analogue was incorporated into the cyclic backbone of the antimicrobial peptide gramicidin S at several sites. The biological activity of the resulting peptidomimetics could then be effectively controlled by ultraviolet/visible light within strictly defined spatial and temporal limits.
Metal Alkoxide Promoted Regio‐ and Stereoselective CO and CC Metathesis of Allenoates with Aldehydes
Authors: Wang Minyan , Fang Zhao , Fu Chunling , Ma Shengming
Published: February 2014

The reaction of 2,3‐allenoates and aldehydes in the presence of an alkoxide affords alkyl 4,5‐diaryl‐3‐oxo‐2‐propylpent‐4(E)‐enoates and cis‐3,4‐diaryloxetanes through a formal CO and CC metathesis. A mechanism for this reaction has been proposed.
Organocatalytic Asymmetric Formation of Steroids
Authors: Halskov Kim Søholm , Donslund Bjarke S. , Barfüsser Sebastian , Jørgensen Karl Anker
Published: February 2014

A novel and simple one‐step approach for the construction of optically active steroids in a highly stereoselective manner by using organocatalysis is presented. The reaction of (di)enals with cyclic dienophiles in the presence of a TMS‐protected prolinol catalyst leads to the construction of important 14 β‐steroids. This new reaction allows an easy access to optically active steroids with a variety of substituents in the A ring in high yields and up to greater than 99 % ee. The reaction has been extended to include the construction of B‐ and D‐homosteroids as well as steroids containing heteroatoms in the B ring. The angular substituent at C13 can be varied and alkyl, ester, and sulfone functionalities are introduced with excellent stereoselectivities. Simple synthetic procedures provide access to a range of naturally occurring steroids such as estrone and related analogues.
Functionalization and hemocompatibility of a styrenic thermoplastic elastomer based on its epoxidized precursor
Authors: Yuan Shuaishuai , Luan Shifang , Yang Huawei , Shi Hengchong , Jin Jing , Song Lingjie , Ma Jiao , Yin Jinghua
Published: February 2014

Poly(ethylene glycol) monomethyl ether (mPEG) was introduced into a glycidyl methacrylate‐modified styrenic thermoplastic elastomer graft copolymer via a ring‐opening reaction with the epoxy group. The chemical compositions of the samples were confirmed by Fourier transform infrared spectroscopy, 1H‐NMR spectroscopy, and gel permeation chromatography. X‐ray photoelectron spectroscopy, atomic force microscopy, and water contact angle measurement were used to investigate the surface properties. The results show that the molecular weight of the mPEG monomer had a great effect on the surface properties of the modified samples. The platelet adhesion and protein adsorption of the samples modified with low‐molecular‐weight mPEG were reduced dramatically relative to those of the virgin styrenic thermoplastic elastomer. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40518.
Hypoxia Modulates the Phenotype of Osteoblasts Isolated From Knee Osteoarthritis Patients, Leading to Undermineralized Bone Nodule Formation
Authors: Chang Joan , Jackson Sonya G. , Wardale John , Jones Simon W.
Published: February 2014

Objective

To investigate the role of hypoxia in the pathology of osteoarthritic (OA) bone by exploring its effect on the phenotype of isolated primary osteoblasts from patients with knee OA.

Methods

OA bone samples were collected at the time of elective joint replacement surgery for knee or hip OA. Normal bone samples were collected postmortem from cadaver donors. Primary osteoblasts were isolated from knee OA bone chips and cultured under normoxic or hypoxic (2% O2) conditions. Alkaline phosphatase activity was quantified using an enzymatic assay, and osteopontin and prostaglandin E2 (PGE2) production was assayed by enzyme‐linked immunosorbent assay. Total RNA was extracted from bone and osteoblasts, and gene expression was profiled by quantitative reverse transcription–polymerase chain reaction.

Results

Human OA bone tissue sections stained positively for carbonic anhydrase IX, a biomarker of hypoxia, and exhibited differential expression of genes that mediate the vasculature and blood coagulation as compared to those found in normal bone. Culture of primary osteoblasts isolated from knee OA bone under hypoxic conditions profoundly affected the osteoblast phenotype, including the expression of genes that mediate bone matrix, bone remodeling, and bone vasculature. Hypoxia also increased the expression of cyclooxygenase 2 and the production of PGE2 by OA osteoblasts. Osteoblast expression of type II collagen α1 chain, angiopoietin‐like 4, and insulin‐like growth factor binding protein 1 was shown to be mediated by hypoxia‐inducible factor 1α. Chronic hypoxia reduced osteoblast‐ mineralized bone nodule formation.

Conclusion

These findings demonstrate that hypoxia can induce pathologic changes in osteoblast functionality consistent with an OA phenotype, providing evidence that hypoxia is a key driver of OA pathology.
In situ product recovery of single‐chain antibodies in a membrane bioreactor
Authors: Meier Kristina , Carstensen Frederike , Scheeren Christoph , Regestein Lars , Wessling Matthias , Büchs Jochen
Published: February 2014

The demand for biopharmaceuticals, such as monoclonal antibodies, has risen significantly over the last years. To be competitive, continuous production processes that yield consistent product quality and an economic advantage are desirable. In this study, an in situ product recovery process is described, involving use of submerged membranes to recover single‐chain antibodies from a continuous fermentation of Hansenula polymorpha yeast cells. Reverse‐flow diafiltration (RFD) was applied to prevent cake‐layer formation. Optimal flux ranges for this process could be identified by a systematic flux step method. The RFD process was optimized, preventing mixing of permeate and unreacted substrate: the space–time yield of antibodies using RFD could be tripled. Increase of the fouling related transmembrane pressure was below 45 Pa min−1 for all applied dilution rates, indicating that the filtration process was stable. The membrane as well as the feeding mode of RFD did not influence cell viability nor product concentration. A wide range of dilution rates was successfully tested, demonstrating that this process is suitable for industrial applications. Biotechnol. Bioeng. 2014;111: 1566–1576. © 2014 Wiley Periodicals, Inc.
Power allocation in OFDM cognitive radio relay networks with outdated channel state information
Authors: Biyanwilage Shashika , Gunawardana Upul , Liyanapathirana Ranjith
Published: February 2014

In this paper, we study power allocation in OFDM cognitive radio (CR) relay networks. The objective of power allocation is to maximize the instantaneous capacity of the CR network. It is assumed that the available channel state information between the secondary and primary users is an outdated but correlated version of the actual instantaneous channel state information. Optimal power allocation schemes are developed for both decode‐and‐forward and amplify‐and‐forward relay assisted CR transmission, assuming that the primary users are subject to average interference constraints and the CR transmitters are subject to maximum transmit power constraint. In addition, suboptimal power allocation schemes with reduced complexity are also proposed. Performance of the proposed schemes is compared with uniform power allocation and numerical results confirm that the proposed power allocation schemes achieve significant capacity improvement in comparison to uniform power loading. Furthermore, the proposed suboptimal power allocation schemes can be used as less complex alternatives for optimal power allocation with some capacity degradation. Copyright © 2014 John Wiley & Sons, Ltd.
N‐Methyl‐21‐thiaporphyrins
Authors: Kaur Tejinder , Lee Way‐Zen , Ravikanth Mangalampalli
Published: February 2014

We synthesized five N‐methyl‐meso‐tetraaryl‐21‐thiaporphyrins in 55–60 % yield by treating the appropriate meso‐tetraaryl‐21‐thiaporphyrin with CH3I. The N‐methyl‐21‐thiaporphyrins were characterized by HRMS, 1D and 2D NMR spectroscopy, absorption spectroscopy, fluorescence spectroscopy, and electrochemical techniques, and the structure of one of the compounds was obtained by X‐ray crystallography. 1D and 2D NMR spectroscopy were used to identify all of the resonances observed in the 1H NMR spectra of the N‐methyl‐21‐thiaporphyrins. NMR studies indicated that the methylation occurred at the pyrrole ring that is opposite to the thiophene ring. In the 1H NMR spectra, the methylation resulted in significant upfield shifts of the pyrrole and thiophene protons; the maximum shifts were noted for the protons of the N‐methylated pyrrole ring of the N‐methyl‐21‐thiaporphyrins. The X‐ray structure of one of the N‐methyl‐21‐thiaporphyrins revealed significant deviation of the N‐methylated pyrrole ring from the reference plane defined by the four meso carbon atoms, and the porphyrin ring is strongly distorted compared to the 21‐thiaporphyrin ring. The absorption studies revealed that the N‐methyl‐21‐thiaporphyrins showed four Q bands and one strong Soret band, which were bathochromically shifted compared to those of the 21‐thiaporphyrins. The electrochemical studies on the N‐methyl‐21‐thiaporphyrins indicated that the oxidation potentials became less positive and there were negligible shifts in the reduction potentials; the HOMO–LUMO energy gap decreased compared with that of the 21‐thiaporphyrins. The N‐methyl‐21‐thiaporphyrins are weakly fluorescent with low quantum yields and singlet‐state lifetimes. The spectral and electrochemical studies indicated that N‐methylation of the pyrrole ring of 21‐thiaporphyrins significantly alters the electronic properties of the 21‐thiaporphyrin macrocycle.
The Nelson–Siegel Model of the Term Structure of Option Implied Volatility and Volatility Components
Authors: Guo Biao , Han Qian , Zhao Bin
Published: February 2014

We develop the Nelson–Siegel model in the context of option‐implied volatility term structure and study the time series of volatility components. Three components, corresponding to the level, slope, and curvature of the volatility term structure, can be interpreted as the long‐, medium‐, and short‐term volatilities. The long‐term component is persistent and driven by macroeconomic variables, the medium‐term by market default risk, and the short‐term by financial market conditions. The three‐factor Nelson–Siegel model has superior performance in forecasting the volatility term structure, with better out‐of‐sample forecasts than the popular deterministic implied volatility function and a restricted two‐factor model, providing support to the literature of component volatility models. © 2014 Wiley Periodicals, Inc. Jrl Fut Mark 34:788–806, 2014
Kinetic modeling of laboratory CO2‐exposure experiments performed on whole rock reservoir samples
Authors: Fischer Sebastian , De Lucia Marco , Liebscher Axel
Published: February 2014

Mineralogical and geochemical observations from laboratory CO2‐exposure experiments on reservoir rocks are compared with predictions from geochemical modeling that was performed using PHREEQC software. The Pitzer‐based Eq 3/6 thermodynamic database, provided by Quintessa Ltd., was applied. For kinetic modeling, a Lasaga‐type rate equation was implemented and different models were parameterized taking kinetic rate law parameters from literature. Based on previous modeling studies a modified inverse modeling approach is presented here. This comprises several different Fe‐proxies and improved statistical ranking preferences that were implemented in particular to better match modeled and measured concentrations of dissolved K+, Fe2+ and Al3+. Compared to the previous approach, the presented modeling results are in good (better) agreement with experimental data. Systematic discrepancies between modeling and observation still occur regarding K‐bearing mineral phases and corresponding K+ brine concentrations. Despite missing correlation between K+ and Cl− concentrations, potential reasons for these discrepancies may be increased K+ brine concentrations during the experiments due to dissolution of K‐rich salt(s), such as sylvite. Much better matches were generated for dissolved Fe2+ concentrations. Goethite mainly controls the chemical behavior of dissolved Fe2+ in kinetic simulations. Based on both the available equilibrium and kinetic modeling results, the ultimate fate of dissolved Al3+ and the analysis of Al‐bearing mineral phases potentially controlling dissolved Al3+ brine concentrations cannot be conclusively determined. The overall best ranked kinetic model comprises anhydrite, dolomite, goethite, K‐feldspar and kaolinite. Despite minor inconsistencies dissolved Fe2+, Al3+ and Si4+ were in particular much better reproduced by the best ranked kinetic models.
Clinical outcome of patients with carcinoma ex pleomorphic adenoma of the parotid gland: A comparative study from a single tertiary center
Authors: Lim Chwee Ming , Hobson Candace , Kim Seungwon , Johnson Jonas T.
Published: February 2014

Background

Carcinoma ex pleomorphic adenoma (CXPA) of the parotid gland is a high‐grade cancer and the prognosis of this cancer has not been compared with non‐CXPA high‐grade primary parotid cancer.

Methods

Retrospective medical chart review of patients with surgically treated high‐grade primary parotid cancer (21 CXPA and 52 non‐CXPA) was performed with correlation with disease‐specific survival, locoregional recurrence, and distant recurrence.

Results

Despite having similar stage of cancer and extent of surgical resection, patients with CXPA had a lower disease‐specific survival compared to non‐CXPA high‐grade primary parotid cancer (p = .02). Salivary duct cancer (SDC) was the commonest histologic variant in both cohorts and around 40% of patients with SDC died of distant recurrence that occurred within 3 years from diagnosis.

Conclusion

CXPA of the parotid gland is a more aggressive cancer compared to non‐CXPA high‐grade primary parotid cancer. SDC was associated with a high chance of delayed distant recurrence, which contributed directly to the mortality of this cancer. © 2014 Wiley Periodicals, Inc. Head Neck 37: 543–547, 2015
Prediagnostic circulating vitamin D levels and risk of hepatocellular carcinoma in European populations: A nested case-control study
Authors: Fedirko Veronika , Duarte-Salles Talita , Bamia Christina , Trichopoulou Antonia , Aleksandrova Krasimira , Trichopoulos Dimitrios , Trepo Elisabeth , Tjφnneland Anne , Olsen Anja , Overvad Kim , Boutron-Ruault Marie-Christine , Clavel-Chapelon Françoise , Kvaskoff Marina , Kühn Tilman , Lukanova Annie , Boeing Heiner , Buijsse Brian , Klinaki Eleni , Tsimakidi Chrysanthi , Naccarati Alessio , Tagliabue Giovanna , Panico Salvatore , Tumino Rosario , Palli Domenico , Bueno-de-Mesquita Bas H. , Siersema Peter D. , Peters Petra H. , Lund Eiliv , Brustad Magritt , Olsen Karina Standahl , Weiderpass Elisabete , Zamora-Ros Raul , Sánchez María-José , Ardanaz Eva , Amiano Pilar , Navarro Carmen , Quirós Ramón J. , Werner Mårten , Sund Malin , Lindkvist Björn , Malm Johan , Travis Ruth C. , Khaw Kay-Tee , Stepien Magdalena , Scalbert Augustin , Romieu Isabelle , Lagiou Pagona , Riboli Elio , Jenab Mazda
Published: February 2014

The association between vitamin D status and hepatocellular carcinoma (HCC) has not been well investigated, despite experimental evidence supporting an important role of vitamin D in liver pathophysiology. Our objective was to investigate the association between prediagnostic circulating 25-hydroxyvitamin D [25(OH)D] serum levels and the risk of HCC in a prospective, nested case-control study among 520,000 participants in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. Each case (n = 138) diagnosed between 1992 and 2010 was matched to one control by age, sex, study center, date and time of blood collection, and fasting status. Serum baseline levels of 25(OH)D were measured by liquid chromatography/tandem mass spectrometry. Multivariable incident rate ratios (IRRs) of HCC associated with continuous (per 10 nmol/L) or categorical levels (tertiles or a priori-defined categories) of prediagnostic 25(OH)D were calculated using conditional logistic regression. Higher 25(OH)D levels were associated with a 49% reduction in the risk of HCC (highest versus lowest tertile: multivariable IRR = 0.51, 95% confidence interval [CI], 0.26 to 0.99; P
trend = 0.04; per 10 nmol/L increase: IRR = 0.80, 95% CI, 0.68–0.94). The finding did not vary substantially by time from enrolment to diagnosis, and did not change after adjustment for biomarkers of preexisting liver damage, nor chronic infection with hepatitis B or C viruses. The findings were not modified by body size or smoking status. Conclusion: In this prospective study on western European populations, serum levels of 25(OH)D were inversely associated with the risk of HCC. Given the rising incidence of this cancer in low-risk developed countries and the strong public health interest surrounding the potentially cancer-protective roles of vitamin D, additional studies in different populations are required. (Hepatology 2014;60:1222–1230)
Beta-catenin signaling in murine liver zonation and regeneration: A Wnt-Wnt situation!
Authors: Yang Jing , Mowry Laura E. , Nejak-Bowen Kari Nichole , Okabe Hirohisa , Diegel Cassandra R. , Lang Richard A. , Williams Bart O. , Monga Satdarshan P.
Published: February 2014

Liver-specific β-catenin knockout (β-Catenin-LKO) mice have revealed an essential role of β-catenin in metabolic zonation where it regulates pericentral gene expression and in initiating liver regeneration (LR) after partial hepatectomy (PH), by regulating expression of Cyclin-D1. However, what regulates β-catenin activity in these events remains an enigma. Here we investigate to what extent β-catenin activation is Wnt-signaling-dependent and the potential cell source of Wnts. We studied liver-specific Lrp5/6 KO (Lrp-LKO) mice where Wnt-signaling was abolished in hepatocytes while the β-catenin gene remained intact. Intriguingly, like β-catenin-LKO mice, Lrp-LKO exhibited a defect in metabolic zonation observed as a lack of glutamine synthetase (GS), Cyp1a2, and Cyp2e1. Lrp-LKO also displayed a significant delay in initiation of LR due to the absence of β-catenin-TCF4 association and lack of Cyclin-D1. To address the source of Wnt proteins in liver, we investigated conditional Wntless (Wls) KO mice, which lacked the ability to secrete Wnts from either liver epithelial cells (Wls-LKO), or macrophages including Kupffer cells (Wls-MKO), or endothelial cells (Wls-EKO). While Wls-EKO was embryonic lethal precluding further analysis in adult hepatic homeostasis and growth, Wls-LKO and Wls-MKO were viable but did not show any defect in hepatic zonation. Wls-LKO showed normal initiation of LR; however, Wls-MKO showed a significant but temporal deficit in LR that was associated with decreased β-catenin-TCF4 association and diminished Cyclin-D1 expression. Conclusion: Wnt-signaling is the major upstream effector of β-catenin activity in pericentral hepatocytes and during LR. Hepatocytes, cholangiocytes, or macrophages are not the source of Wnts in regulating hepatic zonation. However, Kupffer cells are a major contributing source of Wnt secretion necessary for β-catenin activation during LR. (Hepatology 2014;60:964–976)
Evaluation of oriented electrospun fibers for periosteal flap regeneration in biomimetic triphasic osteochondral implant
Authors: Liu Xudong , Liu Shen , Liu Shenghe , Cui Wenguo
Published: February 2014

Osteochondral defects represent a serious clinical problem. Although the cell‐scaffold complexes have been reported to be effective for repairing osteochondral defects, a periosteal flap is frequently needed to arrest leakage of the implanted cells into the defect and to contribute to the secretion of cytokines to stimulate cartilage repair. The electrospun mesh mimicking the function of the flap assists tissue regeneration by preventing cell leakage and merits favorable outcomes in the cartilaginous region. In this study, an oriented poly(ε‐caprolactone) (PCL) fibrous membrane (OEM) was fabricated by electrospinning as a periosteal scaffold and then freeze‐dried with a collagen type I and hyaluronic acid cartilage scaffold (CH) and finally, freeze‐dried with a tricalcium phosphate (TCP) bone substratum. Scanning electron microscopic images show obvious microstructure formation of the trilayered scaffolds, and electrospun fibrous membranes have an oriented fibrous network structure for the periosteal phase. Also shown are opened and interconnected pores with well designed three‐dimensional structure, able to be bound in the CH (chondral phase) and TCP (osseous phase) scaffolds. In vitro results showed that the OEM can promote the orientation of bone marrow mesenchymal stem cell (BMSCs) and BMSCs can penetrate into the CH and TCP. After successfully combining the BMSCs, the tissue‐engineered cartilage which contained the OEM and TCP complex was successfully used to regenerate the osteochondral defects in the rabbit model with greatly improved repair effects. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 102B: 1407–1414, 2014.
Decreased blood loss reduces postoperative complications in resection for hepatocellular carcinoma
Authors: Aramaki Osamu , Takayama Tadatoshi , Higaki Tokio , Nakayama Hisashi , Ohkubo Takao , Midorikawa Yutaka , Moriguchi Masamichi , Matsuyama Yutaka
Published: February 2014

Background

The correlation between blood loss and the risk of postoperative complications was unclear in patients undergoing resection of hepatocellular carcinoma (HCC).

Methods

We studied 539 patients who had resection of HCC. Postoperative complications were recorded according to the modified Clavien‐Dindo classification. Variables were compared between patients with grade III to V complications and those with no or grade I to II. A spline regression analysis was used to estimate the probability of grade III to V complications.

Results

Among variables, blood loss (P = 0.0001), operating time (P = 0.0001), blood transfusion (P = 0.0001), and tumor size (P = 0.02) differed significantly between patients with grade III to V and those with no or I to II. Multivariate analysis revealed that the factor most strongly related to complications was blood loss (odds ratio 1.68; 95% confidence interval [CI] 1.45–1.96, P = 0.0001). Spline regression analysis showed that an increase in blood loss was accompanied by increase in the risk of complication; when the estimated probability of grade III to V complications exceeded 50% (95% CI 30.0–70.0), the corresponding blood loss was 820 ml.

Conclusion

Decrease in blood loss in resection of HCC is accompanied by reduced risk of complications. Surgeons need to minimize blood loss as less as 820 ml.
Achieving Competitiveness in Greek Accommodation Establishments during Recession
Authors: Pappas Nikolaos
Published: February 2014

The article examines the strategies that Greek hotels have implemented to strengthen their competitiveness during recession. The research is based on a nationwide e‐mail survey to hospitality managers/owners. The results reveal that the most important perceived competitiveness factor is cost reduction and implementation of actions against crisis, followed by innovation, human resource management and marketing. The study also proposes actions that can improve the competitiveness of accommodation establishments. The article helps fill the gaps in our understanding of how hospitality firms tackle competition during crises, and suggests managerial policies that can help hospitality firms to strengthen their positioning and competitiveness during crises. Copyright © 2014 John Wiley & Sons, Ltd.
Dual Functionalization of Nanostructures of Block Copolymers with Quantum Dots and Organic Fluorophores
Authors: Chae Seungyong , Kim Jeong‐Hee , Theato Patrick , Zentel Rudolf , Sohn Byeong‐Hyeok
Published: February 2014

Dual functionalization of nanostructures of block copolymers by simultaneous incorporation of two functionalities into the nanostructures is demonstrated. For this purpose, a blending strategy of two block copolymers is employed, which have the same basic chemical structure for each block but differ in small amounts of functional moieties in one of the blocks. Block copolymers containing thiol and fluorophore functionalities are synthesized, utilizing a block copolymer that features a reactive block of activated esters. With thiol‐functionalized block copolymers, selective incorporation of quantum dots (QDs) to lamellar nanostructures is first validated by transmission electron microscopy. Fluorophore functionalization of lamellar nanostructures is also confirmed with fluorophore‐anchored block copolymers by photoluminescence spectroscopy. Then, with a blending strategy of two functionalized block copolymers, dual functionalization of lamellar nanostructures of block copolymers is induced by simultaneous incorporation of QDs and organic fluorophores, which exhibit fluorescence resonance energy transfer due to nanoscale confinement.

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Necessary conditions for discontinuities of multidimensional persistent Betti numbers
Authors: Cerri Andrea , Frosini Patrizio
Published: February 2014

Topological persistence has proven to be a promising framework for dealing with problems concerning the analysis of data. In this context, it was originally introduced by taking into account 1‐dimensional properties of data, modeled by real‐valued functions. More recently, topological persistence has been generalized to consider multidimensional properties of data, coded by vector‐valued functions. This extension enables the study of multidimensional persistent Betti numbers, which provide a representation of data based on the properties under examination. In this contribution, we establish a new link between multidimensional topological persistence and Pareto optimality, proving that discontinuities of multidimensional persistent Betti numbers are necessarily pseudocritical or special values of the considered functions. Copyright © 2014 John Wiley & Sons, Ltd.
On non‐autonomous integro‐differential‐algebraic evolutionary problems
Authors: Waurick M.
Published: February 2014

In this article, we show that a technique for showing well‐posedness results for evolutionary equations in the sense of Picard and McGhee [Picard, McGhee, Partial Differential Equations: A unified Hilbert Space Approach, DeGruyter, Berlin, 2011] established in [Picard, Trostorff, Wehowski, Waurick, On non‐autonomous evolutionary problems. J. Evol. Equ. 13:751‐776, 2013] applies to a broader class of non‐autonomous integro‐differential‐algebraic equations. Using the concept of evolutionary mappings, we prove that the respective solution operators do not depend on certain parameters describing the underlying spaces in which the well‐posedness results are established. Copyright © 2014 John Wiley & Sons, Ltd.
Robust spectral method for numerical valuation of european options under Merton's jump‐diffusion model
Authors: Pindza E. , Patidar K.C. , Ngounda E.
Published: February 2014

We propose a novel numerical method based on rational spectral collocation and Clenshaw–Curtis quadrature methods together with the “” transformation for pricing European vanilla and butterfly spread options under Merton's jump‐diffusion model. Under certain assumptions, such model leads to a partial integro‐differential equation (PIDE). The differential and integral parts of the PIDE are approximated by the rational spectral collocation and the Clenshaw–Curtis quadrature methods, respectively. The application of spectral collocation method to the PIDE leads to a system of ordinary differential equations, which is solved using the implicit–explicit predictor–corrector (IMEX‐PC) schemes in which the diffusion term is integrated implicitly, whereas the convolution integral, reaction, advection terms are integrated explicitly. Numerical experiments illustrate that our approach is highly accurate and efficient for pricing financial options.Copyright © 2014 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 30: 1169–1188, 2014