bluuebunny/crossref_metadata_2025 huggingface dataset:
A single‐layer approach to electrochromic materials
Authors: Percec Simona , Tilford Susan
Published: November 2010

This study is focused on the development of electrochromic (EC) materials that could be incorporated into electrically‐driven switchable devices such as electrochromogenic glasses. The ultimate goal of this research is to depart from the complexity of the EC device construction which is in use today. Such construction consists of three layers each of them incorporating a specific functionality: the electrochromophore, the electrolyte and the ion storage, assembled between two transparent or reflective electrodes. In most of these conventional devices the electrolyte layer is a liquid or a gel. Since solid‐state EC devices are of high commercial interest, we are exploring various avenues to reduce the number of layers to one layer that is all‐solid and electrochromically/electrolytically and ionically functional. The design strategy is based on the use of polymers such as poly(epichlorohydrin‐co‐ethylene oxide), poly(vinyl butyral) and poly(ethylene‐co‐methacrylic acid) ionomer, to which EC properties were introduced by grafting reactions with specifically synthesized carbazole derivatives. A combination of analytical techniques was used to characterize the monomers and the carbazole‐grafted polymers. A proof of concept was demonstrated for a single‐layer, all‐solid‐state EC device consisting of a film of poly(ECH‐co‐EO) containing pendent carbazole groups, assembled between two transparent electrodes, Sn‐doped In2O3 oxide‐coated glasses. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Influence of the poly(propylene imine) generation in the LC properties of ionic codendrimers bearing fluorinated and perhydrogenated chains
Authors: Hernández‐Ainsa Silvia , Barberá Joaquín , Marcos Mercedes , Serrano José Luis
Published: November 2010

A series of codendrimers constituted by the first five generations of poly(propylene imine) (PPI) ionically substituted with 2H,2H,3H,3H‐perfluoroundecanoic acid (af) and undecanoic acid (ac) in a fixed ratio (1:3) (af:ac) have been synthesized and their supramolecular organization has been investigated both in the liquid crystalline state and on a surface. Incompatibility generated by combining fluorinated and perhydrogenated chains in the same molecule causes a peculiar mesomorphic behavior depending on the generation of the codendrimers. Thus smectic A, frustrated smectic A or rectangular columnar mesophases have been detected. Despite their different liquid crystalline organization, they are capable to self‐assemble in homogeneous molecular length layers on a surface, namely mica as revealed by atomic force microscopy (AFM) experiments. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 278–285, 2011
Porphyrin‐functionalized amphiphilic diblock copolypeptides for photodynamic therapy
Authors: Li Ze‐Yong , Wang Hui‐Yuan , Li Cao , Zhang Xiao‐Lu , Wu Xiao‐Jun , Qin Si‐Yong , Zhang Xian‐Zheng , Zhuo Ren‐Xi
Published: November 2010

A series of amphiphilic diblock copolypeptides (ADCs), 5‐(4‐aminophenyl)‐10,15,20‐triphenyl‐porphyrin (APP) conjugated poly(L‐leucine)‐block‐polylysine (APP‐LnKm) with different molar ratios of L‐leucine unit and lysine unit were designed and synthesized. The optimized composition of the polypeptide was determined to be APP‐L109K186, which has high fluorescence quantum yield and could self‐assemble into micelles in an aqueous medium with mean particle size <30 nm. The in vitro study indicates that APP‐L109K186 shows no significant dark cytotoxicity when the concentration is below 200 mg L−1 for HepG2 and HeLa cells. In contrast, the polymer exhibits apparent phototoxicity with low IC50 values toward HepG2 and HeLa cells, implying that the potential high photodynamic therapy efficacy of the polymer. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Optically active helical polymer from radical polymerization of menthyl vinyl ketone
Authors: Wu Shi , Yang Nianfa , Liu Yanling , Cao Jing , Hu Hai , Sun Yunkai , Liu Ji
Published: November 2010

Menthyl vinyl ketone (MVK) was radically polymerized to obtain a polymer with excess of one‐handed helical sense. Like as the anionically polymerized poly‐MVK, the radically polymerized poly‐MVK also kept stable one‐handed helical conformation in solvent. The optical rotation and the circular dichroism signal intensity of the radically polymerized poly‐MVK were larger than that of the anionically polymerized poly‐MVK. The molecular weight of the radically polymerized poly‐MVK was much larger than that of the THF‐soluble part of the anionically polymerized poly‐MVK. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Synthesis of cationic N‐[3‐(dimethylamino)propyl]methacrylamide brushes on silicon wafer via surface‐initiated RAFT polymerization
Authors: Gurbuz Nergiz , Demirci Serkan , Yavuz Serkan , Caykara Tuncer
Published: November 2010

Surface‐initiated reversible addition‐fragmentation chain transfer (SI‐RAFT) polymerization of N‐[3‐(dimethylamino)propyl]methacrylamide (DMAPMA) on the silicon wafer was conducted in attempt to create controllable cationic polymer films. The RAFT agent‐immobilized substrate was prepared by the silanization of hydroxyl groups on silicon wafer with 3‐aminopropylthriethoxysilane (APTS) and by the amide reaction of amine groups of APTS with ester groups of 4‐cyano‐4‐((thiobenzoyl) sulfanyl) pentanoic succinimide ester (CPSE); followed by the RAFT polymerization of DMAPMA using a “free” RAFT agent, that is, 4‐cyanopentanoic acid dithiobenzoate (CPAD) and an initiator, that is, 4,4′‐azobis‐4‐cyanopentanoic acid (CPA). The formation of homogeneous tethered poly(N‐[3‐(dimethylamino)propyl]methacrylamide) [poly(DMAPMA)] brushes, whose thickness can be tuned by reaction time varying, is evidenced by using the combination of grazing angle attenuated total reflectance‐Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy, atomic force microscopy, and water contact‐angle measurements. The calculation of grafting parameters from the number‐average molecular weight, Mn (g/mol) and ellipsometric thickness, h (nm) values indicated the synthesis of densely grafted poly(DMAPMA) films and allowed us to predict a polymerization time for forming a “brush‐like” conformation for the chains. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Synthesis of zwitterionic polymer by SET‐LRP at room temperature in aqueous
Authors: Ding Wei , Lv Chongfu , Sun Ying , Liu Xiaojun , Yu Tao , Qu Guangmiao , Luan Huoxin
Published: November 2010

The Cu0‐mediated single electron transfer‐living radical polymerization of acrylamide andN,N‐dimethyl‐N‐methacryloyloxyethyl‐N‐sulfobutyl ammonium in aqueous at 25 °C using 2‐chloropropionamide as initiator with Cu0powder/tris‐(2‐dimethylamino ethyl)amine (Me6‐TREN) as catalyst system is studied. The results showed the characteristic of the “living” polymerization that were theMnof polymers increased linearly with monomer conversion and the ln([M]0/[M]) increased linearly with time too, meanwhile the narrow molecular of weight distributions were found at most cases. Because of the high rate constant of propagation and bimolecular termination of the acrylamide, the external addition of CuCl2is required to mediate deactivation the early stage of polymerization. In addition, the disproportionation constant of CuIX/L in H2O is higher than in other solvents and the coordination of amino group and CuIItakes place easily, so the isopropanol orN,N‐dimethylformamide is added to control the polymerization. High conversions were achieved within short time and the polymers prepared showed good antipolyelectrolyte properties in inorganic salts solutions. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Magnetoresistance and anomalous thermal hysteresis in La0.67Ca0.33MnO3/CaCu3Ti4O12 composites
Authors: Hua Luo Jiang , Hua HeJing
Published: November 2010

The (1 − x) La0.67Ca0.33MnO3(LCMO)/xCaCu3Ti4O12 (CCTO) (x = 0, 0.01, 0.03, 0.05, and 0.10) composites were fabricated by the sol–gel method and investigated in detail for their electrical transport and magnetoresistance (MR) properties. The X‐ray diffraction and scanning electronic microscopy analysis reveal that both LCMO and CCTO phases are distributed in the composites. Compared with pure LCMO, an obvious enhancement of MR is observed over a wide temperature range for the composites at high external magnetic field. Under 3 T field, the MR increases to a maximum value of 73.4% for x = 0.1 composite. Simultaneously, the thermal hysteresis behavior in resistivity is observed in x = 0.03, 0.05, and 0.1 samples, respectively. The MR enhancement and the abnormal experimental observations are attributed to the enhanced spin disorder at grain boundaries induced by the interaction product layer between LCMO and CCTO.
First‐principles study of CrB4 as a high shear modulus compound
Authors: Xu Hong Bin , Wang Yuan Xu , Lo V. C.
Published: November 2010

First‐principles calculations were carried out to investigate the synthesized orthorhombic CrB4. Our calculations show that the shear modulus of orthorhombic CrB4 is much higher than that of superhard WB4. Moreover, its shear modulus is larger than its bulk modulus. Boron atoms in CrB4 form a strong covalent cage which dramatically increases its mechanical strength. The calculated elastic constants imply that CrB4 is elastically stable. The calculated density of states shows that CrB4 is metallic. The appearance of pesudogap near the Fermi level means that CrB4 is a stable compound. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of Nelumbo nucifera Rhizome Extract on Cell Proliferation and Neuroblast Differentiation in the Hippocampal Dentate Gyrus in a Scopolamine‐induced Amnesia Animal Model
Authors: Yoo Dae Young , Kim Woosuk , Yoo Ki‐Yeon , Lee Choong Hyun , Choi Jung Hoon , Kang Il‐Jun , Yoon Yeo Sung , Kim Dong‐Woo , Won Moo‐Ho , Hwang In Koo
Published: November 2010

A large aquatic herb, Nelumbo nucifera Gaertn, has psychopharmacological effects similar to minor tranquillizers and antistress agents. This study examined the effects of Nelumbo nucifera rhizome extracts (NRE) on cell proliferation and neuroblast differentiation in the hippocampal dentate gyrus (DG) of a rat model of scopolamine‐induced amnesia. Immunohistochemical markers included Ki67, an endogenous marker for active cell cycle, and doublecortin (DCX), a marker for immature neurons and migratory neuroblasts. Scopolamine was administered for 28 days via an ALzet minipump (44 mg/mL delivered at 2.5 µL/h). NRE was administered by gavage, 1 g/kg per day for 28 days. The administration of scopolamine significantly reduced the number of Ki67‐ and DCX‐immunoreactive cells in the DG, whereas scopolamine did not induce any significant changes in mature neurons in the DG. The administration of NRE significantly ameliorated the scopolamine‐induced reduction of Ki67‐ and DCX‐immunoreactive cells in the DG. In addition, the administration of NRE significantly restored the scopolamine‐induced reduction of brain‐derived neurotrophic factor in DG homogenates. These results suggest that NRE can ameliorate the scopolamine‐induced reductions of cell proliferation, neuroblast differentiation and BDNF levels. Copyright © 2010 John Wiley & Sons, Ltd.
Compared ability of garlic (Allium sativum) extract or α‐tocopherol + magnesium association to reduce metabolic disorders and oxidative stress in diabetic rats
Authors: Hfaiedh Najla , Murat Jean Claude , Elfeki Abdellfattah
Published: November 2010

Since some complications of diabetes mellitus may be caused or exacerbated by an oxidative stress, the protective effects of (1) a garlic (Allium sativum) aqueous extract or (2) a combination of α‐tocopherol and magnesium were investigated comparatively in alloxan‐diabetic rats. Garlic extract (1 mL of extract corresponding to 300 mg fresh garlic/kg) or α‐tocopherol (100 mg/kg) + MgCl2(200 mg/kg body weight) were i.p. injected to rats, once a day for 4 weeks. Lipid peroxidation levels and the activities of superoxide‐dismutase, catalase and glutathione peroxidase were then measured in liver and pancreas. Under our experimental conditions, garlic extract or α‐tocopherol + Mg were found to (1) significantly reduce the plasma levels of glucose, total cholesterol and triglyceride and (2) lactate dehydrogenase, alkaline phosphatase and transaminase activities in blood of diabetic animals. In addition, treatment with garlic extract or α‐tocopherol + magnesium appeared to exert an antioxidative activity demonstrated (1) by the increase of catalase, superoxide‐dismutase and glutathione‐peroxidase activities in liver and pancreas, and (2) a lowering of lipid peroxidation level in these organs. In conclusion, both garlic extract and α‐tocopherol + magnesium association were found to alleviate diabetes‐associated metabolic disorders and oxidative stress in rats. Copyright © 2010 John Wiley & Sons, Ltd.
Inhibition of adhesion of Neisseria meningitidis to human epithelial cells by berry juice polyphenolic fractions
Authors: Toivanen Marko , Huttunen Sanna , Lapinjoki Seppo , Tikkanen‐Kaukanen Carina
Published: November 2010

The adhesion of pathogens to host tissues is the requirement for the initiation of the majority of infectious diseases. It was shown recently that the binding of Neisseria meningitidis pili to immobilized human epithelial cells is inhibited by molecular size fractions (10–100 kDa) of berry juices. Additionally, the isolated meningococcal pili bound to polyphenolic fractions of berry juices. The present study investigated the antiadhesive effects of berry juice polyphenolics against living meningococcal bacteria in a human epithelial cell culture model. The ability of bilberry, cranberry, crowberry and lingonberry juice polyphenolic fractions to inhibit the attachment of N. meningitidis bacteria to HEC‐1B human epithelial cells in a cell culture model was examined. The antibacterial effect of the fractions was tested using a microtiter broth microdilution assay. The most effective adhesion inhibition of 75% was achieved with cranberry juice polyphenolic fraction followed by crowberry (63%), bilberry (63%) and lingonberry (57%) juice polyphenolic fractions. Bacterial survival rates after incubation with the fractions varied between 75–100%. The present results suggest berry juice polyphenols as inhibitors of adherence of N. meningitidis. Thus the binding of meningococci to berry juice polyphenols might be protective for the host against the infection. Copyright © 2010 John Wiley & Sons, Ltd.
Mechatronic assistant system for dental drill handling
Authors: Ortiz Simon Jose Luis , Martinez Arturo Minor , Espinoza Daniel Lorias , Romero Velazquez Jose Guadalupe
Published: November 2010

Background

Holding a dental tool for many hours of work is reflected in fatigue and manual tremor, which causes bad handling of rotatory instruments and consequently injuries within the buccal cavity. At present there exists no system to help the medical dentist in the support and handling of the dental drill. We propose the use of a mechatronic system to help the odontologist in handling the dental drill.

Methods

The mechatronic system consists of an articulated arm with force sensors and actuators that are activated electronically. The mechanism was developed so that the handpiece is held simultaneously by the mechatronic arm and the hand of the dentist. Expert dentists and odontology students were asked to execute tasks to assess positioning accuracy and system resolution. Students performed positioning tasks to evaluate adaptation to the system. The subjects drew the contour of a circle with and without the mechatronic assistant to assess positioning accuracy. Similarly, they made cavities on acrylic typodonts to evaluate resolution and accuracy. Adaptation to the system was evaluated by inserting the drill burr into cavities previously made.

Results

The mechatronic system provides support and stability while handling the dental drill. The threshold of force required to move the mechanism prevents involuntary movements affecting the quality of work made on cavities. Positioning accuracy was improved by 53% (p < 0.017) using the system. Similarly, resolution of drilling was improved by 76% (p < 0.001).

Conclusion

We have developed the first mechatronic system to assist dentists in handling the dental drill. The arm allows the dentist to manipulate the tool with smooth and precise movements during the preparation of dental cavities with the application of force. The mechatronic system minimizes manual tremor due to fatigue and reduces the risk of iatrogenic dental injuries. Copyright © 2010 John Wiley & Sons, Ltd.
Photoelastic stress analysis in blood vessel phantoms: three‐dimensional visualization and saccular aneurysm with bleb
Authors: Matsushima M. , Tercero C. , Ikeda S. , Fukuda T. , Arai F. , Negoro M. , Takahashi I.
Published: November 2010

Background

The photoelastic effect is used for stress measurement during endovascular surgery simulation for quantitative evaluation of catheter trajectory in in vitro environments. By extending the capabilities of this sensing technology, its potential for intravascular tools evaluation will increase.

Methods

In this research the error introduced by stress direction on magnitude measurements was studied, then stress measurements were made in the phantom modelling of a saccular aneurysm with bleb. To visualize three‐dimensionally the stress field changes produced by a guide wire in a phantom wall, a scanner and an algorithm relying on maximum likelihood‐expectation maximization are proposed. Three‐dimensional fields at different pressure level were compared with the stress field surrounding the guide wire.

Results

The maximum error in stress magnitude measurements due to stress direction was 2.52%. Stress local maximum was detected in the bleb phantom before rupture. Three‐dimensional visualization was obtained in vasculature phantom with average errors of 10.73%, 4.55%, 3.18% for inner pressures of 80, 120, 160 mmHg, respectively. Stress measurement in the neighbourhood of the guide wire is equivalent to applying an inner pressure of 120 mmHg.

Conclusions

For the presented polariscope, the weak influence of stress direction in magnitude measurements was confirmed. In vasculature phantoms, the three‐dimensional visualization of stress eliminated birefringence visualization distortion and enabled more comprehensive comparison of stress produced by intravascular tools with stress produced by normal blood pressure. Copyright © 2010 John Wiley & Sons, Ltd.
Stabilization of nonlinear sandwich systems via state feedback—Discrete‐time systems
Authors: Wang Xu , Stoorvogel Anton A. , Saberi Ali , Grip Håvard Fjær , Sannuti Peddapullaiah
Published: November 2010

A recent paper (IEEE Trans. Aut. Contr.2010;55(9):2156–2160) considered stabilization of a class of continuous‐time nonlinear sandwich systems via state feedback. This paper is a discrete‐time counterpart of it. The class of nonlinear sandwich systems consists of saturation elements sandwiched between linear systems. We focus first on single‐layer sandwich systems, which consist of a single saturation sandwiched between two linear systems. For such systems, we present necessary and sufficient conditions for semi‐global and global stabilization problems by state feedback, and develop design methodologies to achieve the prescribed stabilization. We extend the results to single‐layer sandwich systems subject to additional actuator saturation. Finally, we discuss further extension to general multi‐layer sandwich systems with an arbitrary number of saturations sandwiched between linear systems, both with and without actuator saturation. The design methodologies can be viewed as extensions of classical low‐gain design methodologies developed during the 1990s in the context of stabilizing linear systems subject to actuator saturation. Copyright © 2010 John Wiley & Sons, Ltd.
Monitoring of an ATP‐Binding Aptamer and its Conformational Changes Using an α‐Hemolysin Nanopore
Authors: Ying Yi‐Lun , Wang Hai‐Yan , Sutherland Todd C. , Long Yi‐Tao
Published: November 2010

An aptamer is a specific oligonucleotide sequence that spontaneously forms a secondary structure capable of selectively binding an analyte. An aptamer’s conformation is the key to specific binding of a target molecule, even in the case of very closely related targets. Nanopores are a sensitive tool for the single‐molecule analysis of DNA, peptides, and proteins transporting through the pore. Herein, a single α‐hemolysin natural nanopore is utilized to sense the conformational changes of an adenosine 5’‐triphosphate (ATP)‐binding aptamer (ABA). The known DNA sequence of the ABA is used as a model to develop real‐time monitoring of molecular conformational changes that occur by binding targets. The native, folded ABA structure has a nanopore unfolding time of 4.17 ms, compared with 0.29 ms for the ABA:ATP complex. A complementary 14‐mer strand, which binds the ABA sequence in the key nucleic acids responsible for folding, forms linear duplex DNA, resulting in a nanopore transit time of 0.50 ms and a higher capture probability than that of the folded ABA oligomer. Competition assays between the ABA:ATP and ABA:reporter complexes are carried out, and the results suggest that the ABA:ATP complex is formed preferentially. The nanopore allows for the detection of an ABA in its folded, ATP‐bound, and linear conformations.
Tracking Stem Cell Differentiation in the Setting of Automated Optogenetic Stimulation
Authors: Stroh Albrecht , Tsai Hsing-Chen , Wang Li-Ping , Zhang Feng , Kressel Jenny , Aravanis Alexander , Santhanam Nandhini , Deisseroth Karl , Konnerth Arthur , Schneider M. Bret
Published: November 2010

Membrane depolarization has been shown to play an important role in the neural differentiation of stem cells and in the survival and function of mature neurons. Here, we introduce a microbial opsin into ESCs and develop optogenetic technology for stem cell engineering applications, with an automated system for noninvasive modulation of ESC differentiation employing fast optogenetic control of ion flux. Mouse ESCs were stably transduced with channelrhodopsin-2 (ChR2)-yellow fluorescent protein and purified by fluorescence activated cell sorting (FACS). Illumination of resulting ChR2-ESCs with pulses of blue light triggered inward currents. These labeled ESCs retained the capability to differentiate into functional mature neurons, assessed by the presence of voltage-gated sodium currents, action potentials, fast excitatory synaptic transmission, and expression of mature neuronal proteins and neuronal morphology. We designed and tested an apparatus for optically stimulating ChR2-ESCs during chronic neuronal differentiation, with high-speed optical switching on a custom robotic stage with environmental chamber for automated stimulation and imaging over days, with tracking for increased expression of neural and neuronal markers. These data point to potential uses of ChR2 technology for chronic and temporally precise noninvasive optical control of ESCs both in vitro and in vivo, ranging from noninvasive control of stem cell differentiation to causal assessment of the specific contribution of transplanted cells to tissue and network function.
Concise Review: Dissecting a Discrepancy in the Literature: Do Mesenchymal Stem Cells Support or Suppress Tumor Growth?
Authors: Klopp Ann H. , Gupta Anshul , Spaeth Erika , Andreeff Michael , Marini Frank
Published: November 2010

The discovery that mesenchymal stem cells (MSCs) are recruited into tumors has led to a great deal of interest over the past decade in the function of MSCs in tumors. To address this, investigators have used a variety of tumor models in which MSCs are added exogenously to determine their impact on tumor development. Interestingly, many studies have reported contradicting results, with some investigators finding that MSCs promote tumor growth and others reporting that MSCs inhibit tumor growth. Many mechanisms have been reported to account for these observations, such as chemokine signaling, modulation of apoptosis, vascular support, and immune modulation. In this review, we analyzed the differences in the methodology of the studies reported and found that the timing of MSC introduction into tumors may be a critical element. Understanding the conditions in which MSCs enhance tumor growth and metastasis is crucial, both to safely develop MSCs as a therapeutic tool and to advance our understanding of the role of tumor stroma in carcinogenesis.
Krüppel-Like Family of Transcription Factor 9, a Differentiation-Associated Transcription Factor, Suppresses Notch1 Signaling and Inhibits Glioblastoma-Initiating Stem Cells
Authors: Ying Mingyao , Sang Yingying , Li Yunqing , Guerrero-Cazares Hugo , Quinones-Hinojosa Alfredo , Vescovi Angelo L. , Eberhart Charles G. , Xia Shuli , Laterra John
Published: November 2010

Tumor-initiating stem cells (alternatively called cancer stem cells, CSCs) are a subpopulation of tumor cells that plays unique roles in tumor propagation, therapeutic resistance, and tumor recurrence. It is becoming increasingly important to understand the molecular signaling that regulates the self-renewal and differentiation of CSCs. Transcription factors are critical for the regulation of normal and neopolastic stem cells. Here, we examined the expression and function of the Krüppel-like family of transcription factors (KLFs) in human glioblastoma (GBM)-derived neurosphere lines and low-passage primary GBM-derived neurospheres that are enriched for tumor-initiating stem cells. We identify KLF9 as a relatively unique differentiation-induced transcription factor in GBM-derived neurospheres. KLF9 is shown to induce neurosphere cell differentiation, inhibit neurosphere formation, and inhibit neurosphere-derived xenograft growth in vivo. We also show that KLF9 regulates GBM neurosphere cells by binding to the Notch1 promoter and suppressing Notch1 expression and downstream signaling. Our results show for the first time that KLF9 has differentiating and tumor-suppressing functions in tumor-initiating stem cells.
Analytically derived fragility relationships for the modern high‐rise buildings in the UAE
Authors: Mwafy Aman
Published: November 2010

Investigating and planning for the expected damage that may hit the earthquake‐prone areas in the UAE should be undertaken in order to predict and mitigate earthquake losses. This paper discusses a framework for developing an essential driving engine in loss estimation systems, namely fragility relationships. Six reference structures, varying in height from 10 to 60 storeys, are selected due to the concentrated economic and human assets in this class of buildings. The reference structures are designed according to the building codes and construction practice adopted in this region. Inelastic fibre‐based simulation models are developed for the buildings using a verified analysis platform, which enables monitoring the spread of yielding and cracking during the multi‐step cyclic analysis. The ground motion uncertainty is accounted for using 20 input ground motions conforming to the latest understanding of the seismo‐tectonic characteristics of the UAE. A large number of inelastic pushover and incremental dynamic collapse analyses are deployed for the reference structures to derive the fragility relationships. The study illustrates the significance of assessing the vulnerability of a population of high‐rise buildings under the effect of various seismic scenarios and the need for expanding this study to cover other classes of structures in this region. Copyright © 2010 John Wiley & Sons, Ltd.
Seismic performance evaluation of diagrid system buildings
Authors: Kim Jinkoo , Lee Young‐Ho
Published: November 2010

In this study, the seismic performance of typical diagrid structures was investigated. To this end, 36‐storey diagrid structures with various slopes of external braces were designed and their seismic responses were evaluated using nonlinear static and dynamic analyses. A tubular structure and a diagrid structure with buckling‐restrained braces were also designed with the same design loads, and their seismic performances were compared with those of the diagrid structures. According to the analysis results, the diagrid structures showed higher overstrength with smaller ductility compared with the tubular structure. It was also observed that as the slope of braces increased the shear lag effect increased and the lateral strength decreased. Both the strength and ductility of diagrid structures increased significantly when the diagonal members were replaced by buckling‐restrained braces. Copyright © 2010 John Wiley & Sons, Ltd.
Column shortening analysis of tall buildings with lumped construction sequences
Authors: Kim Han‐Soo , Jeong Se‐Hun , Shin Seung‐Hak
Published: November 2010

An analysis method with lumped construction sequences for the column shortening of tall buildings is proposed and its efficiency is investigated. The lumped model shows results that are close to the exact model in subsequent shortening as well as total shortening. Different arrangement methods for the lumped model are investigated. The size of the lumping is studied and 1/15 is recommended considering the efficiency of the lumped model. The lumped models can be used efficiently for the three‐dimensional analysis as well as for the plane frame analysis. The proposed method can be used more effectively at the design stage of tall buildings. Copyright © 2010 John Wiley & Sons, Ltd.
Strain gradient effects on flexural strength design of normal‐strength concrete beams
Authors: Ho J. C. M. , Peng J.
Published: November 2010

In the flexural strength design of normal‐strength concrete (NSC) beams, the resultant concrete force and its centroid within the compression zone is generally expressed in an equivalent rectangular stress block. The equivalent concrete stress is expressed as , where is the uni‐axial concrete cylinder strength. Currently, the value of α stipulated in various design codes for NSC is taken as 0.85. Nonetheless, in an experimental study conducted earlier by the authors on NSC columns subjected to concentric and eccentric axial loads, it was found that the value of α significantly depends on strain gradient, which generally increases as strain gradient increases until it reaches a maximum value. Therefore, strain gradient is a critical factor and should be considered in the flexural strength design of NSC members. In this paper, a new flexural strength design method that incorporates the effects of strain gradient is developed for NSC beams. An equivalent rectangular concrete stress block, which is strain‐gradient dependent, is proposed and applied to produce a set of equations for the flexural strength design of singly and doubly reinforced NSC beams with various concrete strengths. Lastly, these equations are converted into charts for practical design application. Copyright © 2010 John Wiley & Sons, Ltd.
TOA estimation of UWB backscattering RFID tag with dual pulse modulation for clutter suppression
Authors: Xu Chi , Law Choi L.
Published: November 2010

To realize precise localization for UWB backscattering RFID system, the arrival time of the direct path in the received signal (referred as time of arrival (TOA)) needs to be accurately estimated. The background clutter is one of the major factors that deteriorates the TOA estimation accuracy in backscattering RFID system. To suppress the background clutter while maintain low‐complexity system design, we propose a novel UWB backscattering RFID system with its tag being implemented with dual pulse (DP) modulation. By transforming the mathematical model of received signal into a proper form, we discover the tag's sequence selection criteria which are able to mitigate the background clutter. For the proposed tag coded with dedicated sequences, a two‐stage TOA estimation algorithm able to effectively mitigate clutter is developed. Simulation results show that the proposed RFID system coupled with the algorithm is able to achieve accurate TOA estimation in the environment where the clutter overwhelms the tag response. Copyright © 2010 John Wiley & Sons, Ltd.
Mixing greedy and predictive approaches to improve geographic routing for VANET
Authors: Wu Tin‐Yu , Wang Yan‐Bo , Lee Wei‐Tsong
Published: November 2010

In recent years, thanks to the development and popularization of wireless network technologies, the issue of vehicularad hocnetwork (VANET) has received great attention, and more and more VANET‐related researches have been brought up. Generally speaking, the biggest difference between VANET and traditionalad hocnetwork is the velocity of carriers because in VANET, the velocity of vehicles, the carriers, is much higher than those in traditionalad hoc. Therefore, it would be a great challenge to forward data efficiently in VANETs and many researches proposed have focused on the development of routing protocols. The current proposed routing protocols are all assumed to simulate in a distributed and ideal environment. As for the complex geographic environments, such as urban scenarios, extra amendments must be needed to improve the efficiency of the routing protocols. Thus, the main purpose of this paper is to design a suitable routing protocol for urban scenarios with better performance and adaptability. For this reason, greedy on straight roads and predictive at the intersections (GSPI) routing protocol is proposed to use greedy mode on straight roads and to use predictive mode at the intersections. In greedy mode, we choose the next hop according to the weight value that combines the distances and multi‐rate. In predictive mode, we predict the directions of the vehicles to determine the next hop. The simulation results reveal that our proposed algorithm indeed proves its feasibility. Copyright © 2010 John Wiley & Sons, Ltd.
Opportunistic scheduling for an OFDMA system with multi‐class services
Authors: Kwon Jeong‐Ahn , Lee Jang‐Won
Published: November 2010

In this paper, we study an opportunistic scheduling problem in an OFDMA system, in which sub‐carriers of the system are allocated to each user in each time slot considering the time‐varying channel condition and QoS requirement of each user. We consider two different classes of services that are represented with different types of utility functions. The utility function for a user in one class is defined as a function of its average data rate, which can be applicable to best‐effort services and the utility function for a user in the other class is defined as a function of its instantaneous data rate, which can be applicable to rate‐sensitive services. Those two types of utility functions have been extensively considered in opportunistic scheduling in wireless networks. However, in most of the previous work, they are considered separately in different problems. In this paper, we formulate a stochastic optimization problem that can treat those two types of utility functions in a single problem, which enables us to implement an opportunistic scheduling algorithm that can consider those two classes of services in a single system in a unified way. Through simulations, we first show that our algorithm provides a good approximation to the optimal solution. In addition, we also verify the appropriateness of our utility models. Copyright © 2010 John Wiley & Sons, Ltd.
Interlevel‐correlated orthogonal space–time block codes based on the expanded signal constellation
Authors: Ma Shang‐Chih
Published: November 2010

Orthogonal space–time block codes provide full diversity with a very simple decoding scheme. However, they do not provide much coding gain. For a given space–time block code, we combine several component codes in conjunction with set partitioning of the expanded signal constellation according to the coding gain distance (CGD) criterion. By providing proper interlevel coding between adjacent blocks, we can design an orthogonal space–time block code with high rate, large coding gain, and low decoding complexity. The error performance of an example code is compared with some codes in computer simulation. These codes are compared based on the situation of the same transmission rate, space diversity order, and state complexity of decoding trellis. Copyright © 2010 John Wiley & Sons, Ltd.
Performance analysis of RTS/CTS scheme in WLAN with the impact of bit errors
Authors: Peng Xiangyu , Jiang Letian , Xu Guozhi
Published: November 2010

To estimate the system performance of RTS/CTS scheme in an error‐prone WLAN channel, this paper proposes a new three‐dimensional Markov model, which considers the impact of bit error on all kinds of frames, and both station short retry limit and long retry limit. The system performance parameters including saturation throughput, packet drop probability, drop time, and average delay are derived using the new Markov model. By comparing the numerical results with simulation results, the model is proved to be more accurate than previous work. The numerical results show that the channel bit error rate has a significant impact not only on system performance, but also on the sensitivity of other system parameters including network scale, channel data rate, and packet length. Copyright © 2010 John Wiley & Sons, Ltd.
Recursion: what is it, who has it, and how did it evolve?
Authors: Coolidge Frederick L. , Overmann Karenleigh A. , Wynn Thomas
Published: November 2010

Recursion is a topic of considerable controversy in linguistics, which stems from its varying definitions and its key features, such as its universality, uniqueness to human language, and evolution. Currently, there appear to be at least two common senses of recursion: (1) embeddedness of phrases within other phrases, which entails keeping track of long‐distance dependencies among phrases and (2) the specification of the computed output string itself, including meta‐recursion, where recursion is both the recipe for an utterance and the overarching process that creates and executes the recipes. There are also at least two evolutionary scenarios for the adaptive value of recursion in human language. The gradualist position posits precursors, such as animal communication and protolanguages, and holds that the selective purpose of recursion was for communication. The saltationist position assumes no gradual development of recursion and posits that it evolved for reasons other than communication. In the latter view, some heritable event associated with a cognitive prerequisite of language, such as Theory of Mind or working memory capacity, allowed recursive utterances. Evolutionary adaptive reasons for recursive thoughts were also proffered, including diplomatic speech, perlocutionary acts, and prospective cognitions. WIREs Cogni Sci 2011 2 547–554 DOI: 10.1002/wcs.131

This article is categorized under:

Linguistics > Evolution of Language
Clipless Cholecystectomy: Which Sealer Should be Used?
Authors: Kavlakoglu Burak , Pekcici Recep , Oral Suleyman
Published: November 2010

Background

The use of the Harmonic Scalpel (HS) for cystic duct ligation began with little data about its efficacy or safety. On the other hand, there is not any literature available about the use of PlasmaKinetic Sealer (PK) for closing the cystic duct in laparoscopic cholecystectomy (LC). Therefore, this study was designed to compare the efficacy and safety of HS and PK for achieving safe closure of the cystic ducts after LC.

Methods

Ninety patients with symptomatic gallstone disease were enrolled in this prospective case control study. The patients were operated with laparoscopic technic and divided into three groups (n = 30) randomly. After the dissection of Calot’s triangle, proximal cystic ducts on common bile ducts were sealed with single surgical clips (SC) in all groups, and in the first group, distal of the cystic ducts also was sealed with single SC and the gallbladders were removed with SC. In the second and third groups, distal of the cystic ducts were sealed with HS and PK, respectively. The gallbladders were removed as sealed cystic ducts with HS and PK. Then, gallbladders were connected to a transducer set and increasing pressure with saline was applied. The bursting pressures of gallbladders were measured and differences between the groups were calculated by using Student’s t test. The value of P < 0.05 was accepted as significant.

Results

In this study, the mean cystic duct bursting pressures were 332.46 ± 4.62 mmHg with SC, 326.56 ± 4.53 mmHg with PK, and 343.06 ± 4.28 mmHg with HS. Differences of the mean cystic duct bursting pressures between the groups were indicated the superior results of HS.

Conclusions

The results of this study indicated that HS is more effective than PK and as safe and effective as SC for cystic duct closure.
Measures to Prevent Surgical Site Infections: What Surgeons (Should) Do
Authors: Diana Michele , Hübner Martin , Eisenring Marie‐Christine , Zanetti Giorgio , Troillet Nicolas , Demartines Nicolas
Published: November 2010

Background

The present study was designed to evaluate surgeons’ strategies and adherence to preventive measures against surgical site infections (SSIs).

Materials and methods

All surgeons participating in a prospective Swiss multicentric surveillance program for SSIs received a questionnaire developed from the 2008 National (United Kingdom) Institute for Health and Clinical Excellence (NICE) clinical guidelines on prevention and treatment of SSIs. We focused on perioperative management and surgical technique in hernia surgery, cholecystectomy, appendectomy, and colon surgery (COL).

Results

Forty‐five of 50 surgeons contacted (90%) responded. Smoking cessation and nutritional screening are regularly propagated by 1/3 and 1/2 of surgeons, respectively. Thirty‐eight percent practice bowel preparation before COL. Preoperative hair removal is routinely (90%) performed in the operating room with electric clippers. About 50% administer antibiotic prophylaxis within 30 min before incision. Intra‐abdominal drains are common after COL (43%). Two thirds of respondents apply nonocclusive wound dressings that are manipulated after hand disinfection (87%). Dressings are usually changed on postoperative day (POD) 2 (75%), and wounds remain undressed on POD 2–3 or 4–5 (36% each).

Conclusions

Surgeons’ strategies to prevent SSIs still differ widely. The adherence to the current NICE guidelines is low for many procedures regardless of the available level of evidence. Further research should provide convincing data in order to justify standardization of perioperative management.
Simplified Alternative to the TRISS Method for Resource‐Constrained Settings
Authors: Nakahara Shinji , Ichikawa Masao , Kimura Akio
Published: November 2010

Background

We developed simple methods of risk adjustment for evaluating the quality of injury care (predicting survival probabilities of the injured) by fully utilizing routinely collected data in injury surveillance and clinical practices. Widely used methods of risk adjustment require additional data that are difficult to collect in resource‐constrained settings.

Methods

We developed logistic regression models that predict survival using data obtained from 9,840 victims aged 15 years or older with blunt traumatic injuries who were registered in the Japan Trauma Data Bank, Japan’s national trauma registry, between January 2004 and December 2007. The models included three predictors: age, an anatomical injury severity parameter such as a simplified severity categorization (minor, moderate, and severe) described in the Injury Surveillance Guidelines, and a physiological status parameter. The models’ abilities to predict survival probabilities were evaluated using the area under the receiver‐operating characteristic curve (AUROCC).

Results

The simplified three‐predictor models showed good performance with the AUROCC ranging from 0.86 to 0.94. In particular, the models with a consciousness level indicator as a physiological parameter showed a high AUROCC, ranging from 0.93 to 0.94, which was not much different from the performance of the widely used method that shows an AUROCC of 0.96.

Conclusions

Simplified methods of risk adjustment that require only routinely collected data will facilitate evaluation and improvement in the quality of injury care in resource‐constrained low‐ and middle‐income countries, where injuries are a growing public health concern.
Hand Involvement in Navajo Neurohepatopathy: A Case Report
Authors: Cheema Tahseen A. , Swanson Scott
Published: November 2010

We report a case of Navajo neurohepatopathy with severe involvement of the hands. It is a progressive sensorimotor neuropathy with distal weakness, areflexia, and reduced sensation in the extremities associated with acral mutilation. The role of possible surgical intervention is demonstrated in this case.
Oxidative Stability of Marine Phospholipids in the Liposomal Form and Their Applications
Authors: Henna Lu F. S. , Nielsen N. S. , Timm‐Heinrich M. , Jacobsen C.
Published: November 2010

Marine phospholipids (MPL) have attracted a great deal of attention recently as they are considered to have a better bioavailability, a better resistance towards oxidation and a higher content of eicosapentaenoic (EPA) and docosahexaenoic acids (DHA) than oily triglycerides (fish oil) from the same source. Due to their tight intermolecular packing conformation at thesn‐2 position and their synergism with α‐tocopherol present in MPL extracts, they can form stable liposomes which are attractive ingredients for food or feed applications. However, MPL are still susceptible to oxidation as they contain large amounts polyunsaturated fatty acids and application of MPL in food and aquaculture industries is therefore a great challenge for researchers. Hence, knowledge on the oxidative stability of MPL and the behavior of MPL in food and feed systems is an important issue. For this reason, this review was undertaken to provide the industry and academia with an overview of (1) the stability of MPL in different forms and their potential as liposomal material, and (2) the current applications and future prospects of MPL in both food and aquaculture industries with special emphasis on MPL in the liposomal form.
Appeasement Obama Style: The Europeanisation of America's Policy in the Middle East?
Authors: Shepherd Robin
Published: November 2010

Under President Obama, American foreign policy towards the conflict in the Middle East, and in particular, its position on Israel, has shifted. In contrast to Bush's pursuit of ‘legitimacy’, Obama is seeking to implement a foreign policy of multilateralist ‘engagement’, regardless of the dubious reputation of some of the states involved. When applying this policy to Israel, the approach of the US has become ‘Europeanised’ and less adamant about the fact that by supporting Israel, the interests of the West are also supported. However, taking this approach will only result in the legitimisation of Europe's worst instincts on this matter and thus further exasperate the situation in the Middle East.