bluuebunny/crossref_metadata_2025 huggingface dataset:
The McLafferty rearrangement in the Glu residue in a cyclic lipopeptide determined by Q‐TOF MS/MS
Authors: Yang Shi‐Zhong , Liu Xiang‐Yang , Mu Bo‐Zhong
Published: July 2008

The intraresidue rearrangement and loss of the side chain of the Glu residue was found through MS/MS analysis of both original and methanol‐esterified lipopeptides. Both Glu and Asp residues in the cyclic lipopeptide were esterified. The MS/MS results showed that the loss of fragment 72 or 86 was induced by McLafferty‐type rearrangement from the Glu or esterified Glu. The mechanism of loss of the Glu residue can be used to determine or to corroborate the existence of the Glu and to help understand the fragment formation in MS/MS. The cleavage mechanism and m/z intensities imply that the sodium ion was easier attached and the cleavage would easily occur at specific sites. Copyright © 2008 John Wiley & Sons, Ltd.
Differences between collisionally activated and electron‐transfer dissociations found for CH2X2(X = Cl, Br, and I) by using alkali‐metal targets
Authors: Sasaki Tomohiro , Matsubara Hiroshi , Hayakawa Shigeo
Published: July 2008

High‐energy collisionally activated dissociation (HE‐CAD) and high‐energy electron‐ transfer dissociation (HE‐ETD) on collisions with alkali‐metal targets (Cs, K, and Na) were investigated for CH2X2+ (X = Cl, Br, and I) ions by tandem mass spectrometry (MS/MS). In the HE‐CAD spectra observed, peaks associated with CH2X+ ions formed by a loss of a halogen atom are always predominant regardless of precursor ions and target metals. The observation of the predominant CH2X+ ions is explained by the lowest energy levels of the fragments of CH2X+ + X among the possible fragment energy levels and internal‐energy distribution in HE‐CAD. In the charge‐inversion spectra, relative peak intensities of the negative ions formed by HE‐ETD strongly depend on the precursor ions and the target metals. While the CHCl2− ion was predominant in the spectra of CH2Cl2+ regardless of target species, the most intense peaks in those of CH2Br2+ and CH2I2+ were ascribed to either Br− or CH2Br− and either I− or I2−, respectively, depending on the target metals. The dependence of the relative intensities of the fragment ions by HE‐ETD on the precursor ions and target species are discussed on the basis of the energy levels of the neutral fragments and the narrow internal‐energy distribution resulting from the near‐resonant neutralization. It was demonstrated that HE‐ETD using the alkali‐metal targets provided rich information on the dissociation of the neutral species. Copyright © 2008 John Wiley & Sons, Ltd.
Synthesis of satellite footprint patterns from time‐modulated planar arrays with very low dynamic range ratios
Authors: Chen Yikai , Yang Shiwen , Nie Zaiping
Published: July 2008

An efficient pattern synthesis approach has been developed for the synthesis of satellite footprint patterns using time‐modulated planar arrays. The approach can be used to effectively control both the ripples in the coverage zone and the sidelobe levels, due to the adoption of time‐modulated antenna arrays. The optimized time sequences and element excitations are obtained by the method based on a combination of a differential evolution strategy (DES) and a modified 2D Woodward–Lawson method. Normally, planar array synthesis is rather time consuming, partly due to the inherently large number of optimization variables and partly due to the fact that the calculation of fitness function is also time consuming. A fast computation approach based on the 2D fast Fourier transform (FFT) is thus applied in the DES for the planar array pattern computation. Several representative examples are presented to show the flexibility and effectiveness of the proposed approach. Copyright © 2008 John Wiley & Sons, Ltd.
HSPB2/MKBP, a novel and unique member of the small heat‐shock protein family
Authors: Hu Zhiping , Yang Binbin , Lu Wei , Zhou Weijun , Zeng Liuwang , Li Ting , Wang Xiang
Published: July 2008

Although proteins belonging to the sHSP superfamily are diverse in sequence and size, most share characteristic features, including 1) a small molecular mass of 12–43 kDa, 2) a conserved α‐crystallin domain of 80–100 residues, 3) formation of large oligomers, 4) a dynamic quaternary structure, and 5) induction by stress conditions and chaperone activity in suppressing protein aggregation. HSPB2/MKBP (myotonic dystrophy kinase‐bind‐protein) retains the structural motif of the α‐crystallin family of HSPs but shows a unique nature compared with canonical family members, characterized by gene allocation, specific binding partners in skeletal muscle, and unique stress responsiveness. MKBP may be involved in the pathogenesis of myotonic dystrophy and contribute to the neuropathology in both Alzheimer's disease and hereditary cerebral hemorrhage with amyloidosis, Dutch type. © 2008 Wiley‐Liss, Inc.
High concentrations of cannabinoids activate apoptosis in human U373MG glioma cells
Authors: Widmer M. , Hanemann C.O. , Zajicek J.
Published: July 2008

Cannabinoids bind to two G‐protein‐coupled receptors, CB1 and CB2, expressed by neurons and cells of the immune system, respectively. Glioma cells (astrocyte‐derived brain tumor cells) express cannabinoid receptors, and numerous in vitro and in vivo studies performed in rodents have concluded that apoptosis could be induced by cannabinoids in these cells. Whether this also applies to human cells is controversial; we, therefore, assessed the effect of cannabinoids on human glioma cell viability with the human astrocytoma cell line U373MG. We report here that U373MG human glioma cells are sensitive only to high concentrations of cannabinoids (>5 μg/ml for Δ9‐THC). Similar concentrations of the compounds promoted a rapid activation of extracellular‐regulated kinase and c‐Jun NH2‐terminal kinase, suggesting that cannabinoid receptors are functional in U373MG cells. Nevertheless, these kinases are not involved in cannabinoid‐induced cell death in U373MG cells, insofar as blocking their activation with specific inhibitors does not reduce cell death. CB1 is expressed in U373MG cells and is involved in cannabinoid‐induced cell death, in that blocking its activation with a specific antagonist (AM251) almost totally prevented cell death following incubation of the cells with Δ9‐THC. In addition, as already reported, some cannabinoids may have modest proproliferative properties in U373MG cells. Human U373MG glioma cells are sensitive only to very high, pharmacologically irrelevant concentrations of cannabinoids, so it seems unlikely that cannabinoids would constitute promising molecules for treating malignant astrocytoma; they do not induce glioma cell death at doses that could be applied safely to humans. © 2008 Wiley‐Liss, Inc.
Okadaic acid increases autophagosomes in rat neurons: Implications for Alzheimer's disease
Authors: Yoon Seung Yong , Choi Jung Eun , Kweon Hee‐Seok , Choe Han , Kim Seong Who , Hwang Onyou , Lee Heuiran , Lee Joo‐Yong , Kim Dong Hou
Published: July 2008

Autophagosomes are accumulated in Alzheimer's disease (AD), but the regulatory pathway of autophagy in AD remains largely unknown. By using electron microscopy, Western blotting, and immunocytochemistry, here we show that autophagosomes are accumulated in rat neurons by okadaic acid (OA), a protein phosphatase‐2A inhibitor known to enhance tau phosphorylation, β‐amyloid (Aβ) deposition, and neuronal death, which are the pathological hallmarks of AD. Autophagy can be generally induced via several distinct pathways, such as inhibition of mTOR or activation of beclin‐1. Interestingly, OA increased both mTOR and beclin‐1 pathways simultaneously, which suggests that autophagy in OA‐treated neurons is induced mainly via the beclin‐1 pathway, and less so via mTOR inhibition. Finally, inhibition of autophagy by 3MA reduced cytotoxicity in OA‐treated neurons. Our novel findings provide new insights into the pathology of and therapeutic intervention for AD. © 2008 Wiley‐Liss, Inc.
A technological platform to optimize combinatorial treatment design and discovery for chronic spinal cord injury
Authors: Guertin Pierre A.
Published: July 2008

Chronic spinal cord injury (SCI) is associated with the development of serious medical concerns. In fact, it is increasingly well documented that most SCI patients who survive the first 24 hr will rapidly develop, within a few months to a few years, cardiovascular problems, type II diabetes, muscle wasting, osteoporosis, immune deficiencies, and other life‐threatening problems. The cellular mechanisms underlying these so‐called secondary health complications remain unclear, and no drug or standard approach has been developed to specifically treat these complications. To investigate the cellular and metabolic changes associated with chronic SCI and functional recovery, work mainly from our laboratory recently has led to the characterization of a mouse model of chronic paraplegia. This review reports cellular, systemic, and metabolic changes (associated mainly with secondary health complications) occurring within a few days to a few weeks after SCI in low‐thoracic spinal cord–transected mice. We also describe our research platform developed to ease technological transfer and to accelerate drug‐screening studies in animals. A global understanding of the many chronic changes occurring after SCI together with efficient tools and approaches for testing new or existing drug candidates is likely to yield the design of innovative treatments against secondary complications that combine cellular plasticity–modulating agents, locomotor network–activating drugs, hormonal therapy, and exercise training. © 2008 Wiley‐Liss, Inc.
Dock4 regulates dendritic development in hippocampal neurons
Authors: Ueda Shuhei , Fujimoto Satoshi , Hiramoto Kiyo , Negishi Manabu , Katoh Hironori
Published: July 2008

Dendrite development is required for establishing proper neuronal connectivity. Rho‐family small GTPases have been reported to play important roles in the regulation of dendritic growth and morphology. However, the molecular mechanisms that control the activities of Rho GTPases in developing dendrites are not well understood. In the present study we found Dock4, an activator of the small GTPase Rac, to have a role in regulating dendritic growth and branching in rat hippocampal neurons. Dock4 is highly expressed in the developing rat brain, predominantly in hippocampal neurons. In dissociated cultured hippocampal neurons, the expression of Dock4 protein is up‐regulated after between 3 and 8 days in culture, when dendrites begin to grow. Knockdown of endogenous Dock4 results in reduced dendritic growth and branching. Conversely, overexpression of Dock4 with its binding partner ELMO2 enhances the numbers of dendrites and dendritic branches. These morphological effects elicited by Dock4 and ELMO2 require Rac activation and the C‐terminal Crk‐binding region of Dock4. Indeed, Dock4 forms a complex with ELMO2 and CrkII in hippocampal neurons. These findings demonstrate a new function of the Rac activator Dock4 in dendritic morphogenesis in hippocampal neurons. © 2008 Wiley‐Liss, Inc.
Regeneration of nigrostriatal dopaminergic axons after transplantation of olfactory ensheathing cells and fibroblasts prevents fibrotic scar formation at the lesion site
Authors: Teng Xichuan , Nagata Isao , Li Hong‐Peng , Kimura‐Kuroda Junko , Sango Kazunori , Kawamura Koki , Raisman Geoffrey , Kawano Hitoshi
Published: July 2008

The fibrotic scar formed after central nervous system injury has been considered an obstacle to axonal regeneration. The present study was designed to examine whether cell transplantation into a damaged central nervous system can reduce fibrotic scar formation and promote axonal regeneration. Nigrostriatal dopaminergic axons were unilaterally transected in rats and cultures of olfactory‐ensheathing cells (OECs), and olfactory nerve fibroblasts were transplanted into the lesion site. In the absence of transplants, few tyrosine hydroxylase–immunoreactive axons extended across the lesion 2 weeks after the transection. Reactive astrocytes increased around the lesion, and a fibrotic scar containing type IV collagen deposits developed in the lesion center. The immunoreactivity of chondroitin sulfate side chains and core protein of NG2 proteoglycan increased in and around the lesion. One and 2 weeks after transection and simultaneous transplantation, dopaminergic axons regenerated across the transplanted tissues, which consisted of p75‐immunoreactive OECs and fibronectin‐immunoreactive fibroblasts. Reactive astrocytes and chondroitin sulfate immunoreactivity increased around the transplants, whereas the deposition of type IV collagen and fibrotic scar formation were completely prevented at the lesion site. Transplantation of meningeal fibroblasts similarly prevented the formation of the fibrotic scar, although its effect on regeneration was less potent than transplantation of OECs and olfactory nerve fibroblasts. The present results suggest that elimination of the inhibitory fibrotic scar is important for neural regeneration. © 2008 Wiley‐Liss, Inc.
Interaction of mitochondrial respiratory inhibitors and excitotoxins potentiates cell death in hippocampal slice cultures
Authors: Schuh Rosemary A. , Matthews Christopher C. , Fishman Paul S.
Published: July 2008

The broad‐spectrum insecticide rotenone, an inhibitor of complex I of the mitochondrial electron transport chain (ETC), gives rise to oxidative stress and bioenergetic failure. Pesticides including rotenone have been implicated in human neurodegenerative diseases, including Parkinson's disease. Another intensively investigated hypothesis of neurodegenerative disease involves the toxic action of the excitatory neurotransmitter glutamate. In the present study, we determined whether concomitant exposure of rotenone plus tetraethylammonium chloride (TEA) or the specific glutamate receptor agonists N‐methyl‐D‐aspartate (NMDA) or α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazoleproprionic acid (AMPA) would cause greater cell death in organotypic hippocampal slice cultures than when given separately. Low, sublethal rotenone (100 nM), TEA (0.5–2.0 mM), NMDA (1.0–10 μM), and AMPA (1.0–10 μM) alone resulted in little cell death as determined by propidium iodide fluorescence. However, cell death was significantly to dramatically potentiated when the hippocampal slices were coincubated with comparable concentrations of rotenone plus TEA, NMDA, or AMPA. Similarly, in the presence of 10 μM NMDA, ETC inhibitors blocking other mitochondrial complexes also potentiated cell death. Immunohistochemical analysis using glial fibrillary acidic protein antibody determined that the cell death was preferentially neuronal. These results demonstrate that two different classes of toxicants can interact, resulting in potentiation of neurotoxicity, and further suggest that a combinatorial therapeutic approach may be required to ameliorate the potentiated cell death. © 2008 Wiley‐Liss, Inc.
Antioxidants partially restore glutamate transport defect in leber hereditary optic neuropathy cybrids
Authors: Sala Gessica , Trombin Federica , Beretta Simone , Tremolizzo Lucio , Presutto Paola , Montopoli Monica , Fantin Marianna , Martinuzzi Andrea , Carelli Valerio , Ferrarese Carlo
Published: July 2008

Leber hereditary optic neuropathy (LHON) is a mitochondrial disease characterized by visual loss resulting from retinal ganglion cell degeneration. Despite the important role of respiratory chain deficiency and oxidative stress induced by mtDNA point mutations affecting complex I, excitotoxic injury has been postulated as a concurrent pathogenic factor. We used transmitochondrial cybrid cell lines constructed using enucleated fibroblasts from three LHON probands carrying the most severe 3460/ND1 mutation and three controls as mitochondria donors, and the osteosarcoma‐derived mtDNA‐less cells, to study the possible efficacy of two selected antioxidant compounds in preventing glutamate uptake reduction previously observed in LHON cybrids. We demonstrated that two antioxidants, Trolox and decylubiquinone, partially restore glutamate transport impairment occurring in LHON cybrids. Rotenone, a classic complex I inhibitor, did not worsen the glutamate uptake defect present in LHON cybrids under basal conditions but significantly reduced glutamate transport in control cybrids. Furthermore, we observed that LHON cybrids showed an increased protein carbonylation under basal conditions, not further affected by rotenone and partially counteracted by antioxidants. Our findings strengthen the hypothesis that the complex I defect associated with LHON causes free radical overproduction, which is responsible for glutamate transport inhibition. We suggest that selected antioxidants may be clinically tested in LHON patients and relatives to restore glutamate uptake defect caused by LHON‐associated free radical overproduction. © 2008 Wiley‐Liss, Inc.
Antioxidant, antiinflammatory and antiapoptotic effects of dapsone in a model of brain ischemia/reperfusion in rats
Authors: Diaz‐Ruiz Araceli , Zavala Carlos , Montes Sergio , Ortiz‐Plata Alma , Salgado‐Ceballos Hermelinda , Orozco‐Suarez Sandra , Nava‐Ruiz Concepción , Pérez‐Neri Iván , Perez‐Severiano Francisca , Ríos Camilo
Published: July 2008

Although dapsone (4,4′‐diaminodiphenylsulfone) has been described as a neuroprotective agent in occlusive focal ischemia in rats, its mechanism of action is still unknown. To explore this mechanism, oxidative, inflammatory and apoptotic processes were evaluated in the striatum of adult rats using a model of ischemia‐reperfusion (I/R), either with or without dapsone treatment. Male Wistar rats were submitted to transient middle cerebral artery occlusion for 2 hr, followed by reperfusion. Rats were dosed either with dapsone (12.5 mg/kg i.p.) or vehicle 30 min before or 30 min after the ischemia onset. Lipid peroxidation (LP) and nitrotyrosine contents were measured 22 hr after reperfusion, and myeloperoxidase activity was evaluated 46 hr after I/R. Different markers for apoptosis and necrosis were also evaluated both at 24 and 72 hr after I/R experimental procedure. LP increased by 37% in ischemic animals vs controls, and this effect was reversed by dapsone treatments. A similar effect was observed regarding nitrotyrosine striatal contents. Myeloperoxidase activity, a marker of inflammatory response, increased 3.7‐fold in ischemic animals vs. control rats, and dapsone treatment antagonized that effect. Although apoptosis was increased by the effect of ischemia at both evaluation times, dapsone antagonized that effect only at 72 hr after surgery. Dapsone antagonized all of the I/R end points measured, showing a remarkable ability to decrease markers of damage through antioxidant, antiinflammatory, and anti‐apoptotic effects. © 2008 Wiley‐Liss, Inc.
On the factors modulating the intensity of the tropical rainbelt over West Africa
Authors: Nicholson Sharon E.
Published: July 2008

This article presents a case study of a wet and a dry year over West Africa. These 2 years, 1955 and 1983, are characterized by rainfall anomalies of one sign throughout West Africa, including the Sahel and Guinea Coast (the no‐dipole cases defined in previous studies). The contrast in rainfall is related to a general weakening and intensification of the tropical rainbelt in the dry year (1983) and the wet year (1955), respectively. The study, limited to the month of August, examines the factors that modulate the intensity of the rainbelt. The more intense rainbelt of 1955 is associated with an anomalously strong tropical easterly jet (TEJ) and a slight northward displacement of the African easterly jet of the Northern Hemisphere (AEJ‐N). The link between the TEJ and rainfall is a causal one, with the strong TEJ enhancing rainfall by enhancing upper‐level divergence and sustaining a strong Hadley‐type overturning over West Africa, with strong vertical motion. In 1983, a weak TEJ and vertical alignment of the AEJ‐N and TEJ axes promote a weak rainbelt and ubiquitous drought. The factors that produce a rainfall dipole (i.e. an opposition in the sign of anomalies between the Sahel and the Guinea Coast) are notably different. The dipole results from meridional displacements of the circulation and rainbelt, rather than changes in rainbelt intensity. Although the strong TEJ is a prime factor, the development of the dipole requires the development of strong and vertically extensive equatorial westerlies. These are produced by strong surface pressure gradients over the Atlantic and West Africa. Copyright © 2008 Royal Meteorological Society
Analysis of a 27‐year rainfall data (1977–2003) in the Sultanate of Oman
Authors: Kwarteng Andy Y. , Dorvlo Atsu S. , Vijaya Kumar Ganiga T.
Published: July 2008

Analysis of variation of rainfall in space, time and amounts, and its attendant effect on the ecosystem is vital in arid and semi‐arid environments where the resource is scare, highly variable and unpredictable. In this study, we analyse the characteristics of rainfall in the Sultanate of Oman using data recorded between 1977 and 2003. The data is divided into six geomorphic compartments to represent the various topographic regions in Oman. The average yearly rainfall varies from a low of 76.9 mm in the interior region to a high of 181.9 mm in the Dhofar Mountains, with an average of 117.4 mm for the whole country. Mann–Kendall statistics show a negative but insignificant rainfall trends for the datasets. In northern Oman, the main rainfall season occurs between December and April and that accounts for 57.8–82.9% of the annual rainfall. February and March record the highest rainfall accounting for 35.3 to 42% of the yearly rainfall. The Dhofar Mountains and surrounding areas in southern Oman are dominated by the khareef season in July–August, which produces 44.3 to 67.5% of the rainfall in that area. The number of days of light rainfall (<10 mm per day) is the most dominant and accounts for 66–95% of the rain. Rain in excess of 50 mm per day is rare in Oman (0.4 and 2.9%), but when it does occur can result in serious consequences such as flash flooding, human catastrophes and land degradation. Rainfall records indicate that Muscat and surrounding areas are susceptible to tropical cyclones and catastrophic rainfall (>100 mm rainfall per day) approximately every 50 years. Copyright © 2008 Royal Meteorological Society
Characteristics of the leaf parts of some traditional Korean salad plants used for food
Authors: Chon Sang‐Uk , Heo Buk‐Gu , Park Yong‐Seo , Cho Ja‐Yong , Gorinstein Shela
Published: July 2008

BACKGROUND: Total phenolics content, antioxidant activity and cytotoxicity of the methanol extracts from leaf parts of 13 Korean traditional salad plants were investigated in order to determine their properties.

RESULTS: The highest phenolics content (mg ferulic acid equivalents kg−1 dry weight (d.w.), omit one) was found in methanol extracts from Polygonum aviculare, at 293.7 ± 6.0, followed by Euonymus alatus, at 250.7 ± 3.3, Saxifraga stolonifera, at 125.0 ± 8.1 and Ligularia fischeri, at 122.5 ± 5.9. The methanol plant extracts dose‐dependently increased free radical scavenging activity. Methanol extracts of Polygonum aviculare, Euonymus alatus and Saxifraga stolonifera, at 31 mg kg−1, exhibited the highest 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical scavenging activity (%) by 90.8 ± 4.2, 85.7 ± 3.9 and 64.1 ± 3.2, respectively. According to 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay, the methanol extracts from Portulaca oleracea (IC50 < 25.0 µg mL−1) showed the highest cytotoxicity against Calu‐6, followed by Plantago asiatica (49.2 µg mL−1) and Osmunda japonica (89.6 µg mL−1).

CONCLUSION: Total phenolics content of the tested plant extracts was correlated with the DPPH radical scavenging activity, suggesting the phenolics compounds are contributing to the antioxidant properties of Korean salad plants. The leaf parts of the 13 Korean traditional salad plants described here that are currently used as foods may also provide some benefit to human health, and research into their potential benefits as preventative and/or therapeutic agents is warranted. Copyright © 2008 Society of Chemical Industry
A modern regimen of pre‐operative concurrent chemo‐radiation therapy in locally advanced rectal cancer
Authors: Bazarbashi Shouki , el‐Bassiouni Mazen , Abdelsalam Mahmoud , Soudy Hussein , Sanea Nasser al , Jabbar Alaa Abdul , Manji Mohamed , Fagih Mosa , Ajarim Dahish
Published: July 2008

Purpose

To evaluate the efficacy and toxicity of preoperative concurrent capecitabine and radiotherapy in the treatment of resectable locally advanced rectal cancer (LARC).

Materials and Methods

We conducted a phase II trial to assess pathological complete response, tumor downstaging, toxicity and survival of capecitabine (825 mg/m2 orally, twice daily) with radiotherapy (50.4 Gy/28 fractions) in 31 patients with LARC (cT3/T4 or N+) staged by endoscopic ultrasound (EUS).

Results

Median age was 53 years; with M:F ratio of 1:1.58; 77.4% had Eastern Cooperative Oncology Group performance status of 1. EUS showed that 67.7% of tumors were T3, 19.4% were T4, and 58% were node positive. Of 30 patients who had surgery, 6.5% achieved pathological complete remission (pCR). Tumor and nodal downstaging were achieved in 53.9% and 50% of patients, respectively. Grade 3/4 toxicities were mainly diarrhea (35.5%) and proctitis (32.3%). Sphincter preservation was achieved in 4/21 (15%) of patients initially planned for abdominoperineal resection. The median follow‐up was 46 months (Range: 1.47–63.9), and the 3‐year disease‐free and overall survival were 59.8% and 76.6%, respectively.

Conclusion

Capecitabine given concurrently with radiation therapy is generally well tolerated, and proved to be an effective radiosensitizer in the neoadjuvant treatment of locally advanced rectal cancer, yielding results comparable to those reported with 5‐FU. J. Surg. Oncol. 2008;98:167–174. © 2008 Wiley‐Liss, Inc.
Using the Delphi method to assess the potential of Taiwan's hot springs tourism sector
Authors: Lee Cheng‐Fei , King Brian Edward
Published: July 2008

The purpose of the present study is to identify the various factors that influence the competitiveness of the hot springs tourism sector. The research draws on the models of Ritchie and Crouch, Dwyer and Kim, and Enright and Newton, who concluded that destination competitiveness is determined by three major components: resources and attractors, destination strategies and environments. The investigation produced both qualitative and quantitative data using the Delphi technique. An expert panel reached consensus about priorities for the development of Taiwan's hot springs tourism sector and provided written justifications for their responses. This paper reports on the qualitative findings of the three‐round Delphi survey and provides a supply‐side perspective on Taiwan's hot springs tourism sector. An examination of the expert comments concluded that the Taiwanese are increasingly concerned with good health and longevity. This emerging characteristic offers new business opportunities for the providers of hot springs tourism experiences to extend their appeal into health protection and medical treatments. However, if they are to achieve sustainable development and ensure high‐quality visitor experiences, hot springs proprietors will need to work closely with local governments and communities to promote sustainable use of natural hot springs and to conduct routine inspections of spa premises. Overall, the future of the hot springs tourism sector appears to be promising. Copyright © 2008 John Wiley and Sons, Ltd.
Concentration, productivity and profitability in the Italian commercial accommodation sector
Authors: Succurro Marianna
Published: July 2008

This study avails itself of the Aida data bank from which were taken the accounting data for the 2,518 limited companies active in the Italian accommodation sector in the years 2000–2006. The research aims at describing the structural characteristics and the competitive advantages of the Italian accommodation sector. The Italian position as leader would seem to be threatened by the entry into the market place of new‐comer countries. Understanding the sector's industrial organisation would appear to be a particularly important step towards the implementation of an effective policy for the industry. Copyright © 2008 John Wiley & Sons, Ltd.
Ultrafast photonic crystal lasers
Authors: Englund D. , Altug H. , Ellis B. , Vučković J.
Published: July 2008

We describe recent progress in photonic crystal nanocavity lasers with an emphasis on our recent results on ultrafast pulse generation. These lasers produce pulses on the picosecond scale, corresponding to only hundreds of optical cycles. We describe laser dynamics in optically pumped single cavities and in coupled cavity arrays, at low and room temperature. Such ultrafast, efficient, and compact lasers show great promise for applications in high‐speed communications, information processing, and on‐chip optical interconnects.
Modelling of laser surface alloying and dispersing of ceramics
Authors: Rohde M. , Dimitrova D.
Published: July 2008

Laser‐supported processes can be used to modify the electrical and thermal properties of ceramic substrates locally. These processes are characterized by a strong thermal interaction between the laser beam and the ceramic surface that leads to localized melting. During the dynamic melting process an additive material is injected into the melt pool in order to modify the physical properties. The heat and mass transfer during this dynamic melting and solidification process has been studied numerically in order to identify the dominating process parameters. Simulation tools based on a finite‐volume method have been developed to describe the heat transfer, fluid flow and the phase change during the melting and solidification of the ceramic. The results of the calculation have been validated against experimental results.
Probing the Effects of Hydrophilic Branch Size, Distribution, and Connectivity in Amphiphilic Polyethylene
Authors: Berda Erik B. , Wagener Kenneth B.
Published: July 2008

Acyclic diene metathesis (ADMET) polymerization/hydrogenation methodology was used to synthesize a family of amphiphilic polyethylenes (PEs) with precisely placed poly(ethylene glycol) branches. Four structural parameters are varied in this report: size of the hydrophilic pendant group, manner in which the pendant group is connected to the backbone, distance between the pendant moieties along the backbone, and saturation of the polyolefin backbone. Varying the branch size with other parameters held constant results in negligible effects on thermal behavior. However, when either the distribution of branches or manner of connection of the branches is altered, changes in the thermal behavior become clear. These slight structural changes allow tunability of the structural morphology from fully amorphous to semicrystalline materials melting over a range of temperatures above 60 °C.

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Tetraalkylammonium Salts of Amino Acids and Sulfur‐Containing Amino Acids as Effective Co‐Initiators of Free Radical Polymerization in the Presence of Aromatic Ketones
Authors: Ścigalski Franciszek , Pączkowski Jerzy
Published: July 2008

Photoredox pairs, composed of xanthone or thioxanthone derivatives acting as light absorbers and tetrabutylammonium salts of amino acids or sulfur‐containing amino acids as co‐initiators, were studied as photoinitiators for free‐radical polymerization. The mechanism of free‐radical formation was established using the laser flash photolysis. Measurements of polymerization kinetics show that the photoinitiation ability of the xanthone‐ or thioxanthone‐derivative/amino acid or sulfur‐containing amino acid pairs depends on the initiator and co‐initiator properties, mostly on the triplet state lifetime of xanthone or thioxanthone derivatives.

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Polymers that Contain Ligated Metals in their Side Chain: Building a Foundation for Functional Materials in Opto‐Electronic Applications with an Emphasis on Lanthanide Ions
Authors: Shunmugam Raja , Tew Gregory N.
Published: July 2008

Organic polymers that contain ligated metals offer a variety of unique properties which include luminescence, electro‐ and photochemistry, catalysis, charge, magnetism, and thermochromism. These organic–inorganic hybrid materials have the potential to offer novel active matrixes for advanced devices. Continued progress in synthetic chemistry and molecular characterization will enable such advanced materials. Here the focus is restricted to side‐chain metal complexes with emissive properties that highlight the use of lanthanide ions as opposed to the often‐studied transition metal complexes.

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Facile Synthesis of Polyaniline‐Polypyrrole Nanofibers for Application in Chemical Deposition of Metal Nanoparticles
Authors: Xu Ping , Han Xijiang , Wang Chao , Zhang Bin , Wang Xiaohong , Wang Hsing‐Lin
Published: July 2008

Polyaniline‐polypyrrole (PANI‐PPy) nanofibers with high aspect ratios have been synthesized by a one‐step, surfactant‐assisted chemical oxidative polymerization from mixtures of aniline (An) and pyrrole (Py) monomers. PANI‐PPy nanofibers synthesized with an excess of either PANI or PPy show similar spectral (UV‐vis and FT‐IR) characteristics as the individual homopolymers, whereas nanofibers from an equimolar mixture of An and Py display unique spectral characteristics. PANI‐PPy nanofibers undergo a spontaneous redox reaction with metal ions to produce metal nanoparticles with various morphologies and/or sizes. These findings may open new opportunities for synthesizing functional polymer nanofibers and metal nanoparticles with controllable sizes and/or morphologies.

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High Conductivity PEDOT Using Humidity Facilitated Vacuum Vapour Phase Polymerisation
Authors: Fabretto Manrico , Zuber Kamil , Hall Colin , Murphy Peter
Published: July 2008

The synthesis of high conductivity poly(3,4‐ethylenedioxythiophene) (PEDOT) films using vacuum vapour phase polymerisation is reported. Water vapour is introduced into the chamber and results suggest that it acts as a proton scavenger during polymerisation. Process optimisation leads to PEDOT films that have high conductivity and a blue‐black appearance. Poor quality films have lower conductivity and a characteristic greenish colour. UV‐vis‐NIR spectra show that poor PEDOT films are characterised by higher absorption in the UV‐vis region and an absorption plateau in the NIR region, which suggests an increased level of disrupted conjugation along the polymer backbone or higher oligomer content. Conversely, high quality PEDOT is characterised by an extended NIR absorption tail and lower absorption in the UV‐vis region.

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Stereoselective Interaction between Isotactic and Optically Active Poly(lactic acid) and Phenyl‐Substituted Poly(lactic acid)
Authors: Tsuji Hideto , Matsuoka Hiroshi
Published: July 2008

Isotactic and optically active poly(D‐lactic acid) (PDLA) and phenyl‐substituted poly(lactic acid)s (Ph‐PLAs), i.e., poly(D‐phenyllactic acid) (Ph‐PDLA) and poly(L‐phenyllactic acid) (Ph‐PLLA), were synthesized and stereospecific interactions between the synthesized polymers were investigated by their thermal properties and crystallization behavior using differential scanning calorimetry (DSC). The DSC measurements indicated that PDLA is miscible with Ph‐PLAs and that the attractive interaction between PDLA and L‐configured Ph‐PLA is higher than that between PDLA and D‐configured Ph‐PDLA. In other words, the latter result means that poly(lactic acid) (PLA) has a higher stereoselective attractive interaction with Ph‐PLA with the reverse configuration than with Ph‐PLA of the same configuration. These results strongly suggest that PLA‐based materials with a wide variety of physical properties and biodegradability can be fabricated by blending them with substituted PLAs with the reverse and same configurations.

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Association of ERCC1 polymorphisms and susceptibility to nasopharyngeal carcinoma
Authors: Yang Zhi‐Hui , Dai Qiong , Kong Xiang‐Li , Yang Wen‐Li , Zhang Lin
Published: July 2008

The normal function of excision repair cross complementing group 1 (ERCC1) is essential for maintaining genomic integrity and preventing cellular neoplastic transformation, and multiple studies have reported an association between ERCC1 polymorphisms and increased risk of cancers. To test whether the genetic variants of ERCC1 gene modify the risk of nasopharyngeal carcinoma (NPC), we compared the 8092 C > A and 19007 C > T single nucleotide polymorphisms (SNPs) and the haplotypes of ERCC1 between 267 patients with NPC and 304 healthy controls. Linkage disequilibrium was observed between the two SNPs loci (D′ = 0.861). Significant differences of allele frequencies were found for ERCC1 8092C > A between the cases and controls. Individuals with 8092 C allele showed 1.411‐fold (OR = 1.411, 95% CI, 1.076–1.850, P = 0.014) increased risk of developing NPC, and the CC haplotype was associated with a significantly increased risk of NPC (OR = 1.712; 95% CI, 1.211–2.421; P = 0.013). No interactions were found between 8092C > A polymorphism and genders, smoking status and alcohol consumption. These results suggested that the polymorphism of ERCC1 8092 C > A might be a contributing factor in the development of NPC in Chinese population. © 2008 Wiley‐Liss, Inc.
Could a perfect model ever satisfy a naïve forecaster? On grid box mean versus point verification
Authors: Göber Martin , Zsótér Ervin , Richardson David S.
Published: July 2008

Numerical models forecast grid box means, whereas forecasters have to deliver point forecasts, often in the form of ‘the most severe weather possible in a small area’. There can be substantial differences between areal means and point values, depending on the subgrid‐scale variability. Forecasters are generally well aware of subgrid‐scale variability when making local predictions of severe events. However, in evaluating the model this is often left out of consideration.

An experiment was performed to estimate the effect of ‘imperfectly verifying’ grid box means against point observations. A ‘perfect model’ was constructed by taking the grid box average of high‐density observations of daily precipitation amount, but the verification of this ‘perfect’ forecast is far from being accurate. The model deviation from the observations is minimal for small precipitation amounts, and becomes larger as more severe events are to be forecast. The error solely due to the wrong kind of verification is of the order of the forecast error itself.

If one has to verify against point observations, the baseline to compare numerical models against is not the theoretical best score value but the score achieved by the “perfect model”. Thus, this study underlines again the imperative to compare numerical models against upscaled observation.

Even a perfect model could not nearly satisfy a naïve forecaster who just wants to pass a model value to a customer in need of a point forecast. Good forecasters apply some post‐processing in order to estimate the subgrid‐scale variability and thus the probability of exceeding some threshold. Copyright © 2008 Royal Meteorological Society
Biliary fibrosis in microsurgical extrahepatic cholestasis in the rat
Authors: Sánchez‐Patán Fernando , Anchuelo Raquel , Corcuera María‐Teresa , Casado Isabel , Gómez‐Aguado Fernando , Aller María‐Angeles , Cruz Arturo , Alonso María‐José , Arias Jaime
Published: July 2008

A new model of extrahepatic cholestasis, using a microsurgical technique, is performed as an alternative to the traditional model of the bile duct ligated‐rat, in order to study the stage of fibrosis in the long‐term. Male Wistar rats were divided into two groups: I (Sham‐operated, n = 9) and II [Microsurgical Cholestasis (MC), n = 10]. After 4 weeks, portal pressure, types of portosystemic collateral circulation, mesenteric venous vasculopathy, hepatic function test, and liver histopathology were studied by using the Knodell index and fibrosis was determined by reticulin and Sirius red stains. The animals with MC presented portal hypertension with extrahepatic portosistemic collateral circulation, associated with mesenteric venous vasculopathy and increased plasma levels of bilirubin (6.30 ± 1.80 vs. 0.22 ± 0.37 mg/dL; P = 0.0001), alkaline phosphatase (293.00 ± 82.40 vs. 126.30 ± 33.42 U/L; P = 0.001), AST (380.00 ± 78.50 vs. 68.33 ± 11.74 IU/L; P = 0.0001), ALT (87.60 ± 22.32 vs. 42.22 ± 7.89 IU/L; P = 0.0001), and LDH (697.76 ± 75.13 vs. 384.80 ± 100.03 IU/L; P = 0.0001). On the contrary, plasma levels of albumin decreased (2.72 ± 0.12 mg/dl vs. 2.99 ± 0.10; P = 0.001). The microsurgical resection of the extrahepatic biliary tract in the rat produces an experimental model of hepatic inflammation, characterized by a high Knodell hepatic activity index (4), bile proliferation, and fibrosis. © 2008 Wiley‐Liss, Inc. Microsurgery, 2008.
Minimum free energy for an electromagnetic conductor with memory
Authors: Amendola G. , Fabrizio M. , Golden J. M.
Published: July 2008

A closed expression is determined in the frequency domain for the minimum free energy associated with a state of a linear electromagnetic conductor with memory effects, using the fact that this quantity is equal to the maximum recoverable work obtainable from the given state of the material. Another equivalent expression is also derived and applied to evaluate explicit formulae for a discrete spectrum model. In particular, for such a model we present the results corresponding to only one inverse time decay for each of the three kernels of the constitutive equations. These results clearly show the effects of various parameters on the expression for the minimum free energy. Copyright © 2008 John Wiley & Sons, Ltd.
Linear instability of ideal flows on a sphere
Authors: Skiba Yuri N.
Published: July 2008

A unified approach to the normal mode instability study of steady solutions to the vorticity equation governing the motion of an ideal incompressible fluid on a rotating sphere is considered. The four types of well‐known solutions are considered, namely, the Legendre‐polynomial (LP) flows, Rossby–Haurwitz (RH) waves, Wu–Verkley (WV) waves and modons. A conservation law for disturbances to each solution is derived and used to obtain a necessary condition for its exponential instability. By these conditions, Fjörtoft's (Tellus 1953; 5:225–230) average spectral number of the amplitude of an unstable mode must be equal to a special value. In the case of LP flows or RH waves, this value is related only with the basic flow degree. For the WV waves and modons, it depends both on the basic flow degree and on the spectral distribution of the mode energy in the inner and outer regions of the flow. Peculiarities of the instability conditions for different types of modons are discussed. The new instability conditions specify the spectral structure of growing disturbances localizing them in the phase space. For the LP flows, this condition complements the well‐known Rayleigh–Kuo and Fjörtoft conditions related to the zonal flow profile. Some analytical and numerical examples are considered. The maximum growth rate of unstable modes is also estimated, and the orthogonality of any unstable, decaying and non‐stationary mode to the basic flow is shown in the energy inner product.

The analytical instability results obtained here can also be applied for testing the accuracy of computational programs and algorithms used for the numerical stability study. It should be stressed that Fjörtoft's spectral number appearing both in the instability conditions and in the maximum growth rate estimates is the parameter of paramount importance in the linear instability problem of ideal flows on a sphere. Copyright © 2008 John Wiley & Sons, Ltd.
Continuous dependence results for a class of nonlinear heat equations in a cylindrical region
Authors: Philippin G. A. , Proytcheva V. , Vernier‐Piro S.
Published: July 2008

In this paper, we derive bounds for the solutions of a quasilinear heat equation in a finite cylindrical region if the far end and the lateral surface are held at zero temperature, and a nonzero temperature is applied at the near end. Some continuous dependence inequalities are also obtained. We also investigate the case in which a given heat flux is prescribed at the near end, instead of a given temperature. Copyright © 2008 John Wiley & Sons, Ltd.
Formal verification of tail distribution bounds in the HOL theorem prover
Authors: Hasan Osman , Tahar Sofiène
Published: July 2008

Tail distribution bounds play a major role in the estimation of failure probabilities in performance and reliability analysis of systems. They are usually estimated using Markov's and Chebyshev's inequalities, which represent tail distribution bounds for a random variable in terms of its mean or variance. This paper presents the formal verification of Markov's and Chebyshev's inequalities for discrete random variables using a higher‐order‐logic theorem prover. The paper also provides the formal verification of mean and variance relations for some of the widely used discrete random variables, such as Uniform(m), Bernoulli(p), Geometric(p) and Binomial(m, p) random variables. This infrastructure allows us to precisely reason about the tail distribution properties and thus turns out to be quite useful for the analysis of systems used in safety‐critical domains, such as space, medicine or transportation. For illustration purposes, we present the performance analysis of the coupon collector's problem, a well‐known commercially used algorithm. Copyright © 2008 John Wiley & Sons, Ltd.
Special power series expansions of monogenic functions around surfaces of codimension two
Authors: Peña Peña Dixan , Sommen Frank
Published: July 2008

In this paper we will focus on power series expansions around special surfaces of codimension two, in particular around spheres and products of spheres. This will include a version of the Cauchy–Kowalewski extension theorem around these surfaces. This higher codimension result was only obtained so far in the flat case (see Partial Differential Equations with Complex Analysis. Pitman Research Notes Mathematical Series, vol. 262. Longman Science and Technology: Harlow, 1992; 61–92; Mathematics and its Applications, vol. 53. Kluwer Academic Publishers Group: Dordrecht, 1992). Copyright © 2008 John Wiley & Sons, Ltd.
Hodge–Helmholtz decompositions of weighted Sobolev spaces in irregular exterior domains with inhomogeneous and anisotropic media
Authors: Pauly Dirk
Published: July 2008

We study in detail Hodge–Helmholtz decompositions in nonsmooth exterior domains Ω⊂ℝN filled with inhomogeneous and anisotropic media. We show decompositions of alternating differential forms of rank q belonging to the weighted L2‐space Ls2, q(Ω), s∈ℝ, into irrotational and solenoidal q‐forms. These decompositions are essential tools, for example, in electro‐magnetic theory for exterior domains. To the best of our knowledge, these decompositions in exterior domains with nonsmooth boundaries and inhomogeneous and anisotropic media are fully new results. In the Appendix, we translate our results to the classical framework of vector analysis N=3 and q=1, 2. Copyright © 2008 John Wiley & Sons, Ltd.
Global solvability for a large flux of a three‐dimensional time‐dependent Navier–Stokes problem in a straight cylinder
Authors: Pileckas K. , Zaja̧czkowski W.
Published: July 2008

The unique global existence of a solution to nonstationary Navier–Stokes system with prescribed nonzero flux F(t) in an infinite three‐dimensional pipe is proved. The obtained solution remains close to the corresponding nonstationary Poiseuille flow. Moreover, it converges to the Poiseuille flow as |x3|→∞. Copyright © 2008 John Wiley & Sons, Ltd.