bluuebunny/crossref_metadata_2025 huggingface dataset:
Searching for stable hept‐C62X2 (X = F, Cl, and Br): Structures and stabilities of heptagon‐containing C62 halogenated derivatives
Authors: Sun Lili , Tang Shuwei , Chang Yingfei , Wang Zhanliang , Wang Rongshun
Published: May 2008

To determine the geometries of the most stable hept‐C62X2 (X = F, Cl, and Br) isomers, all 967 possible hept‐C62F2 isomers have been orderly optimized using AM1, HF/STO‐3G, B3LYP/3‐21G, and B3LYP/6‐31G* methods, and chlorofullerenes and bromofullerenes, which are isostructural with five most stable hept‐C62F2 isomers, were regarded as candidates of the most stable isomer, and optimized at the B3LYP/6‐31G* level. The results reveal that 2,9‐ and 9,62‐hept‐C62X2 (X = F, Cl, and Br) are the two most stable isomers with slight energy difference. The halogenation releases strain energy of hept‐C62, and all halogenated fullerenes are more chemically stable than hept‐C62 with lower EHOMO and higher ELUMO. All five most stable hept‐C62X2 (X = F, Cl, and Br) isomers are energetically favorable, and their thermodynamic stability decreases along with the increase of sizes of addends. Only hept‐C62F2 isomers show high thermodynamic stability, and they are potentially synthesized in experiments. 59,62‐squ‐C62X2 (X = F, Cl, and Br) were computed for comparison, and they are found to be more stable than their heptagon‐containing isomers. © 2008 Wiley Periodicals, Inc. J Comput Chem 2008
Physiological ecology of overwintering in hatchling turtles
Authors: Costanzo Jon P. , Lee Richard E. , Ultsch Gordon R.
Published: May 2008

Temperate species of turtles hatch from eggs in late summer. The hatchlings of some species leave their natal nest to hibernate elsewhere on land or under water, whereas others usually remain inside the nest until spring; thus, post‐hatching behavior strongly influences the hibernation ecology and physiology of this age class. Little is known about the habitats of and environmental conditions affecting aquatic hibernators, although laboratory studies suggest that chronically hypoxic sites are inhospitable to hatchlings. Field biologists have long been intrigued by the environmental conditions survived by hatchlings using terrestrial hibernacula, especially nests that ultimately serve as winter refugia. Hatchlings are unable to feed, although as metabolism is greatly reduced in hibernation, they are not at risk of starvation. Dehydration and injury from cold are more formidable challenges. Differential tolerances to these stressors may explain variation in hatchling overwintering habits among turtle taxa. Much study has been devoted to the cold‐hardiness adaptations exhibited by terrestrial hibernators. All tolerate a degree of chilling, but survival of frost exposure depends on either freeze avoidance through supercooling or freeze tolerance. Freeze avoidance is promoted by behavioral, anatomical, and physiological features that minimize risk of inoculation by ice and ice‐nucleating agents. Freeze tolerance is promoted by a complex suite of molecular, biochemical, and physiological responses enabling certain organisms to survive the freezing and thawing of extracellular fluids. Some species apparently can switch between freeze avoidance or freeze tolerance, the mode utilized in a particular instance of chilling depending on prevailing physiological and environmental conditions.J. Exp. Zool. 309A:297–379, 2008. © 2008 Wiley‐Liss, Inc.
Enhanced thoracic gene delivery by magnetic nanobead‐mediated vector
Authors: Li Wenzhong , Ma Nan , Ong Lee‐Lee , Kaminski Alexander , Skrabal Christian , Ugurlucan Murat , Lorenz Peter , Gatzen Hans‐Heinrich , Lützow Karola , Lendlein Andreas , Pützer Brigitte M. , Li Ren‐Ke , Steinhoff Gustav
Published: May 2008

Background

Systemic gene delivery is limited by the adverse hydrodynamic conditions on the collection of gene carrier particles to the specific area. In the present study, a magnetic field was employed to guide magnetic nanobead (MNB)/polymer/DNA complexes after systemic administration to the left side of the mouse thorax in order to induce localized gene expression.

Methods

Nonviral polymer (poly ethyleneimine, PEI) vector‐gene complexes were conjugated to MNBs with the Sulfo‐NHS‐LC‐Biotin linker. In vitro transfection efficacy of MNB/PEI/DNA was compared with PEI/DNA in three different cell lines as well as primary endothelial cells under magnetic field stimulation. In vivo, MNB/PEI/DNA complexes were injected into the tail vein of mice and an epicardial magnet was employed to attract the circulating MNB/PEI/DNA complexes.

Results

Endocytotic uptake of MNB/PEI/DNA complexes and intracellular gene release with nuclear translocation were observed in vitro, whereas the residues of MNB/PEI complexes were localized at the perinuclear region. Compared with PEI/DNA complexes alone, MNB/PEI/DNA complexes had a 36‐ to 85‐fold higher transfection efficiency under the magnetic field. In vivo, the epicardial magnet effectively attracted MNB/PEI/DNA complexes in the left side of the thorax, resulting in strong reporter and therapeutic gene expression in the left lung and the heart. Gene expression in the heart was mainly within the endothelium.

Conclusions

MNB‐mediated gene delivery could comprise a promising method for gene delivery to the lung and the heart. Copyright © 2008 John Wiley & Sons, Ltd.
Cascade Reactions in Polymeric Nanoreactors: Mono (Rh)‐ and Bimetallic (Rh/Ir) Micellar Catalysis in the Hydroaminomethylation of 1‐Octene
Authors: Gall Barbara , Bortenschlager Martin , Nuyken Oskar , Weberskirch Ralf
Published: May 2008

The concept of micellar catalysis was transferred to the hydroaminomethylation of 1‐octene with N,N‐dimethylamine. In the first series of experiments a rhodium(I) complex with amphiphilic triphenylphosphane functionalized poly(2‐oxazoline)s as macroligand was applied as catalyst. Results obtained under standard hydroformylation conditions (T = 100 °C, p = 50 bar) were not satisfying with regard to activities and selectivities of the hydroaminomethylation reaction. Rising the temperature to 150 °C increased the yield of amine to 22% with a corresponding n/iso selectivity of 7.5 and a TOF number of 461 h−1. Best results were obtained by applying a dual Rh/Ir catalyst within the polymeric micelles leading at lower temperature of 130 °C to an amine yield of 24% with a corresponding n/iso selectivity of 11 and TOF numbers of about 600 h−1.

magnified image
On the well‐posedness of the Cauchy problem for an MHD system in Besov spaces
Authors: Miao Changxing , Yuan Baoquan
Published: May 2008

This paper is devoted to the study of the Cauchy problem of incompressible magneto‐hydrodynamics system in the framework of Besov spaces. In the case of spatial dimension n⩾3, we establish the global well‐posedness of the Cauchy problem of an incompressible magneto‐hydrodynamics system for small data and the local one for large data in the Besov space Ḃ (ℝn), 1⩽p<∞ and 1⩽r⩽∞. Meanwhile, we also prove the weak–strong uniqueness of solutions with data in Ḃ (ℝn)∩L2(ℝn) for n/2p+2/r>1. In the case of n=2, we establish the global well‐posedness of solutions for large initial data in homogeneous Besov space Ḃ (ℝ2) for 2<p<∞ and 1⩽r<∞. Copyright © 2008 John Wiley & Sons, Ltd.
A note on blow‐up for fast diffusive p‐Laplacian with sources
Authors: Liu Wenjun
Published: May 2008

In this note we improve the result of Theorem 3.1 in Yin and Jin (Math. Meth. Appl. Sci. 2007; 30(10):1147–1167) and establish a blow‐up result for certain solution with positive initial energy. Copyright © 2008 John Wiley & Sons, Ltd.
Concerns of former breast cancer patients about disease recurrence: a validation and prevalence study
Authors: van den Beuken‐van Everdingen Marieke H. J. , Peters Madelon L. , de Rijke Janneke M. , Schouten Harry C. , van Kleef Maarten , Patijn Jacob
Published: May 2008

Objective: The present study has three aims: first, to evaluate the psychometric properties of the Dutch version of the CARS (CARS‐DLV). Second, to measure the prevalence of concerns about disease recurrence in former breast cancer patients and identify potential predictors and third, to establish how fear of recurrence was effecting quality of life.

Methods: A prospective study was carried out on breast cancer patients (n=136) who had undergone curative treatment. Eligible patients completed an extensive questionnaire consisting of the CARS (fear of recurrence), HADS (anxiety and depression), BPI (pain), RAND (quality of life), LOT (optimism) and the PCS (catastrophzing).

Results: This study confirmed the good internal consistency, test–retest stability and construct validity of the CARS (Dutch Language version). Moderate to high levels of fear of disease recurrence were found in 56% of 136 breast cancer survivors. Worries about health and death were the most prominent. Pain was a strong predictor of overall fear and of fear on the four sub domains of the CARS. The prevalence of fear decreased significantly with age. Education level, living arrangements and time since the last treatment did not predict the prevalence of overall fear. Fear of recurrence was negatively correlated with quality of life.

Conclusion: The CARS‐DLV proved to be a valuable instrument to measure women's' concerns about breast cancer recurrence. More than half of former breast cancer patients indicated moderate to severe concerns about disease recurrence. Health and death worries were the most prominent. The levels of worry were independent of the time since diagnosis. Copyright © 2008 John Wiley & Sons, Ltd.
Psychosocial factors and survival after diagnosis of inoperable non‐small cell lung cancer
Authors: Akechi Tatsuo , Okamura Hitoshi , Okuyama Toru , Furukawa Toshiaki A. , Nishiwaki Yutaka , Uchitomi Yosuke
Published: May 2008

Objective: Although several previous studies have investigated the association between psychosocial factors and the survival of lung cancer patients, most previous studies were flawed by severe methodological limitations. The purpose of the present study was to use a rigorous study design to investigate the association between relevant psychosocial factors and survival after a diagnosis of inoperable non‐small cell lung cancer (NSCLC).

Methods: The subjects were 122 consecutive newly diagnosed patients with inoperable NSCLC. Patients coping with cancer, psychological distress, clinical depression, and social support were evaluated after diagnosis but before treatment and 2 months later. After a 2‐year follow‐up period, 108 patients had died. The survival data were censored for the remaining 14 patients. The influence of psychosocial factors after diagnosis but before treatment on survival time was analyzed using a Cox regression, with adjustments for well‐established (definite and/or possible) prognostic factors. The stability of the investigated psychosocial factors was also examined.

Results: None of the examined psychosocial factors significantly predicted survival time among the patients with inoperable NSCLC. Among the biomedical factors that were examined, advanced clinical stage, a high serum lactate dehydrogenase level, and not receiving chemotherapy were independently associated with shorter survival periods. Most of the psychosocial factors exhibited a moderate to high stability.

Conclusions: We found little convincing evidence that psychosocial factors after cancer diagnosis had a clinically relevant effect on the survival of inoperable patients with NSCLC. Copyright © 2008 John Wiley & Sons, Ltd.
Satisfaction of early breast cancer patients with discussions during initial oncology consultations with a medical oncologist
Authors: Brown R. F. , Hill C. , Burant C. J. , Siminoff L. A.
Published: May 2008

Objective: The purpose of this report is to extend the current understanding of patient satisfaction by examining expectations of a sample of breast cancer patients and concordance with their medical oncologists about the content of consultations and the importance of consultation items.

Methods: Three hundred and ninety‐five female early stage breast cancer patients of 56 oncologists participated. Patients and oncologists completed a matched questionnaire measuring (a) met expectations, (b) concordance over content and item importance, and (c) satisfaction.

Results: Overall patient satisfaction was extremely high (x=91/100%) although expectations were not met at the stated level desired. Patients and physicians disagreed over what was conveyed and received. Higher overall satisfaction was predicted by levels of met expectations (unstandardized beta=0.69, p=0.008, SE=0.26) and concordance over (a) content (unstandardized beta=1.09, p=0.002, SE=0.34) and (b) importance (unstandardized beta=−0.78, p=0.006, SE 0.28).

Conclusion: Although patient expectations were not well met and physician–patient discord was high about the content of consultations and the importance of consultation items, patients reported high levels of satisfaction. Expectation fulfillment and levels of concordance predicted satisfaction. Copyright © 2008 John Wiley & Sons, Ltd.
The prevalence and clinical impact of pulmonary artery sling on school‐aged children: A large‐scale screening study
Authors: Yu Jung‐Min , Liao Chung‐Pin , Ge Shuping , Weng Zen‐Chung , Hsiung Ming‐Chon , Chang Jia‐Kan , Chen Fong Lin
Published: May 2008

Background

Airway obstruction is a leading cause of mortality and morbidity in patients with pulmonary artery sling (PAS). Early identification of PAS is imperative for prompt initiation of appropriate treatments.

Objective

Our aim was to investigate the prevalence and clinical impact of PAS on school‐aged children through a large‐scale pre‐sports participation cardiovascular screening (PPCVS) study.

Methods

A total of 186,213 school‐aged children underwent portable two‐dimensional echocardiography (2DE) study in a PPCVS study between 2001 and 2004 in Taichung City, Taiwan. We prospectively collected data on the prevalence of PSA, demographics, clinical features, tracheo‐bronchial anomalies (TBA), on computed tomography (CT), pulmonary function test (PFT), follow‐up data in 1 year, and clinical outcomes.

Results

PAS was identified in 11 children (8 males/3 females) with a median age of 13 years (range: 7.2–13.7 years). The prevalence of PAS was 1 in 17,000 school‐aged children. The majority of children with PAS had recurrent broncho‐pulmonary infections (90.9%) and asthmatic cough (81.8%), which had a low positive predictive value of PAS (<1%). Seven patients had diffused complete cartilaginous rings. The other four patients were found to have prominent localized external compression of the trachea or bronchus. No coexisting intracardiac anomalies were found. Two patients had mental retardation. Seven patients underwent surgical correction without mortality or major complications. After surgery, significant improvement in PFT was shown in forced expiratory volume in 1 s (FEV1) and functional vital capacity (FVC).

Conclusions

This is the first study to determine the prevalence of PAS as 59 per million school‐aged children by a large‐scale screening using 2DE. Although the majority of children with PAS have associated TBA and impaired pulmonary function, all patients with PAS were unrecognized due to non‐specific symptoms. Early identification of PAS and surgery result in significant improvement in pulmonary function. Pediatr Pulmonol. 2008; 43:656–661. © 2008 Wiley‐Liss, Inc.
Novel route for preparation of tubular TiO2 microstructures
Authors: Reedo V. , Järvekülg M. , Lõhmus A. , Mäeorg U.
Published: May 2008

In the present work we report a novel phenomenon and mechanism of tubular oxide structure formation. Microtubes of titanium oxide were obtained by deposition of solvent‐free metal butoxide polymer layer on glass substrate and following exposure to humid atmosphere. Dissolving the formed layered system in hexane led to the formation of microtubular oxide structures. The obtained tubes were characterized by SEM and optical microscopy, and a rolled‐up nanosheet morphology was shown. Rolling of oxide gel sheet is proposed as the formation mechanism for this novel microtubular material. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Simultaneous synthesis of gold nanoparticles and conducting poly(3,4‐ethylenedioxythiophene) towards optoelectronic nanocomposites
Authors: Salsamendi M. , Marcilla R. , Döbbelin M. , Mecerreyes D. , Pozo‐Gonzalo C. , Pomposo J. A. , Pacios R.
Published: May 2008

In this paper, a new method for obtaining poly(3,4‐ethylenedioxythiophene) (PEDOT/PSS)/gold nanocomposites is described. In a first step, PEDOT/PSS gold nanoparticle aqueous dispersions were obtained by simultaneous chemical synthesis of PEDOT and gold nanoparticles in the presence of PSS that acts as a stabilizer. In a second step, these PEDOT/PSS gold nanoparticle dispersions were used to formulate nanocomposites by mixing the initial dispersion with commercially available PEDOT/PSS aqueous dispersion. Nanocomposite thin films, obtained by casting these dispersions, present an intimate contact between the inorganic and organic components. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Osseous and vascular anatomical variations within the C1–C2 complex: a radiographical study using computed tomography angiography
Authors: Moftakhar Parham , Gonzalez Nestor R. , Khoo Larry T. , Holly Langston T.
Published: May 2008

Background

One of the limiting factors of C1–C2 fixation is the location of the vertebral artery (VA). The authors sought to assess the potential variations in atlanto–axial VA anatomy using computed tomography angiography (CTA).

Methods

Detailed measurements were made on digital images of 106 patients undergoing CTA at our institution (54 males, 52 females; mean age 56, range 20–86). Distances, diameters and angles of osseous and vascular elements of the atlanto–axial complex were measured.

Results

Optimal C1 and C2 screw trajectories demonstrated wide variations among patients. The size of the VA groove or foramen was not predictive of exact arterial location or size.

Conclusions

The size, location and path of the VA cannot be precisely predicted by the appearance of osseous structures such as the transverse foramina and/or the VA groove. CTA provides additional information regarding the atlanto–axial complex, and should be considered as a useful adjunct in the preoperative evaluation of select patients. Copyright © 2008 John Wiley & Sons, Ltd.
Equation‐based policy optimization for agent‐oriented system dynamics models
Authors: Duggan Jim
Published: May 2008

Within system dynamics, optimization has played an important role in identifying the best range of parameter values for policies in any given model. Optimal solutions focus on discovering the best combination of model parameters, within a fixed policy equation structure, that maximize or minimize a payoff function. This paper presents a new optimization approach for system dynamics. It enables decision makers to vary policy equation structures during the optimization process. The resulting optimization approach—based on genetic algorithms—can explore the search space in order to discover the best combination of parameters and equation‐based strategies for a given system dynamics problem. The approach is best suited to the class of system dynamics problems that are agent‐based, and the work is evaluated using a case study based on the four‐agent beer game. Copyright © 2008 John Wiley & Sons, Ltd.
A study of the surface analysis of some water‐soluble polymers by inverse gas chromatography
Authors: Aşkın Ayşegül , Yazıcı Demet Topaloğlu
Published: May 2008

The surface characterization of 2‐(dimethylamino)ethylmethacrylate (DMA) and 2‐(N‐morpholino)ethylmethacrylate (MEMA) homopolymers and DMA–MEMA diblock copolymer was studied using inverse‐gas chromatography (IGC).

The analyzed surface properties of (co)polymers were the dispersive component of the surface energy ($\gamma_{s}^{d}$) and the acid–base characters of (co)polymer surfaces. The specific free energy (ΔGsp), enthalpy (ΔHsp), and entropy (ΔSsp) of adsorption of polar probes on (co)polymers were calculated. The values of ΔHsp were correlated with both the donor and the modified acceptor numbers (AN) of the probes to quantify the acidic KA and the basic KD parameters of (co)polymer surfaces. The values obtained for the KA and KD parameters indicated basic characters for the surface of (co)polymers. The dispersive component values of the surface energy and the acid–base surface parameters of the DMA–MEMA diblock copolymer surface were found to be between those homopolymers as expected. Copyright © 2008 John Wiley & Sons, Ltd.
Pigment layers and precious metal sheets by energy‐dispersive x‐ray fluorescence analysis
Authors: Cesareo Roberto , Brunetti Antonio , Ridolfi Stefano
Published: May 2008

A portable energy‐dispersive x‐ray fluorescence (EDXRF) equipment was used to measure pigments and precious metal composition. From the x‐ray spectra it was also possible to assign each pigment to the correct pigment layer, and in the case of metal sheets (e.g. gildings) to identify the correct layer distribution. Several methods have also been developed to determine the thickness of pigment layers and metal sheets. They were specifically applied to measure gold thickness in Giotto's halos in the Chapel of the Scrovegni in Padua, and in gilded copper objects from the Royal Tombs of Sipán and from the Museum of Sicán. Copyright © 2008 John Wiley & Sons, Ltd.
SEMI‐empirical and empirical formulas for calculation of K‐shell ionization cross sections by proton impact: a comparison
Authors: Kahoul A. , Nekkab M. , Deghfel B.
Published: May 2008

According to the plane wave Born approximation (PWBA) and the binary encounter approximation (BEA) models, it is possible to fit the cross sections obtained with any atomic element at any particle energy using a scaling law for a K‐shell. The semi‐empirical K‐shell ionization cross sections are then deduced by fitting the available experimental data normalized to their corresponding theoretical values. For the empirical K‐shell ionization cross sections, a third‐order polynomial was used to fit the same experimental data for protons. Our results are compared with the predictions of the ECPSSR theory and with other earlier works. Good agreement is obtained, but it is emphasized that the ultimate solution is to deduce the cross sections by fitting the available experimental data for each element separately. Copyright © 2008 John Wiley & Sons, Ltd.
Defining a Learning Curve for Laparoscopic Cardiomyotomy
Authors: Grotenhuis Brechtje A. , Wijnhoven Bas P. L. , Jamieson Glyn G. , Devitt Peter G. , Bessell Justin R. , Watson David I.
Published: May 2008

Background

This study was designed to determine whether there is a learning curve for laparoscopic cardiomyotomy for the treatment of achalasia.

Methods

All patients who underwent a primary laparoscopic cardiomyotomy for achalasia between 1992 and 2006 in our hospitals were identified from a prospective database. The institutional and the individual surgeon’s learning experiences were assessed based on operative and clinical outcome parameters. The outcomes of cardiomyotomies performed by consultant surgeons versus supervised trainees also were compared.

Results

A total of 186 patients met the inclusion criteria; 144 procedures were undertaken by consultant surgeons and 42 by a surgical trainee. The length of operation decreased after the first ten cases in both the institutional and each individual experience. The rate of conversion to open surgery also was significantly higher in the first 20 cases performed. Intraoperative complications, overall satisfaction with the outcome, reoperation rate, and postoperative dysphagia were not associated with the institutional or the surgeon’s operative experience. Although the length of the operation was greater for surgical trainees (93 versus 79 minutes; p < 0.01), no differences in outcome between the operations performed by consultant surgeons and surgical trainees were detected.

Conclusion

An institutional (20 cases) and an individual (10 cases) learning curve for laparoscopic cardiomyotomy for achalasia can be defined. The clinical outcome for laparoscopic cardiomyotomy does not differ between supervised surgical trainees and consultant surgeons.
Promotion of Cancer Family History Awareness: Jameslink Cancer Risk Assessment Tool at Community Health Fairs
Authors: Kelly Kimberly M. , Porter Kyle , Remy Amber , Westman Judith A.
Published: May 2008

This article examines the impact of providing personalized familial cancer risk assessments with theJameslinkCancer Risk Assessment Tool. Users of theJameslink(N = 166) at eight community health fairs completed a survey including demographic, psychosocial and behavioral variables to better understand responses to theJameslink. No differences were found between whites and those of other races for variables of interest, indicating suitability of theJameslinkfor diverse populations. Those with higherJameslink‐assessed risk had higher perceived risk of cancer. Approximately half (53.8%) reported that they would speak to their physician about theirJameslink‐assessed risk. A regression foundJameslink‐assessed risk, cancer worry, and perceived risk of cancer predicted intentions to speak to a physician about their risk. In addition, open‐ended data provided suggestions to improve theJameslink. Changes in content and format were suggested; however most were happy with the program and encouraged its promotion. The lack of findings for differences as a function of race bolsters the use of computerized Cancer Risk Assessment Tools in diverse communities. The positive feedback of users and the close association between cancer risk assessment, perceived risk, and intention to speak to a physician are supportive of continued use and development of Cancer Risk Assessment Tools in the community to promote awareness of cancer risk.
First space-borne high-spatial-resolution optical imagery of the Antarctic from Formosat-2
Authors: Liu Cheng-Chien , Chang Yueh-Cheng , Huang Stefani , Wu Frank , Wu An-Ming , Kato Soushi , Yamaguchi Yasushi
Published: May 2008

Coordinating and collecting satellite data of changing polar environments is one of the prime activities of International Polar Year (IPY) 2007–08 (Rapley et al. 2004). Within this framework, the requirements to obtain spaceborne snapshots of the Polar Regions and key high latitude processes have been prepared by the international cryospheric community under the auspices of the approved IPY project titled the Global Inter-agency IPY Polar Snapshot Year (GIIPSY). Earlier efforts in manoeuvring Radarsat-1 in a special mode provided radar images with a spatial resolution of 30 m over the entirety of Antarctica during September–October 1997 (Jezek et al. 1998). Limited to their altitude (AL), swath (SW) and pointing capability (PC), however, the operation of optical satellites with high-spatial-resolution sensors is generally restricted to certain latitudes. For example, Landsat (AL:705 km/SW:185 km/PC:0°) mission has been able to provide high-spatial-resolution optical imagery only to ~81°N to ~81°S since the 1980s. The coverage is now extended to ~86° by ASTER (AL:705 km/SW:60 km/PC:24°) (Kargel et al. 2005), but there has been no availability of space-borne optical image of the polar regions with a resolution equivalent or higher than Landsat type sensors with latitudes higher than 86°, until the successful operation of Formosat-2 (AL:891 km/SW:24 km/PC: ± 45° across and along track). Equipped with two-axes high torque reaction wheels, Formosat-2 is able to point not only to ± 45° across track, but also to ± 45° along track (Liu et al. 2007). Figure 1 shows the accessible areas (longer lines: along track ± 0°, across track ± 45°; shorter lines: along track ± 0°, across track ± 30°) and the corresponding ground tracks (solid curves) of Formosat-2 in the Polar Regions. Note that the accessible areas would be even greater if the pointing direction is also set to ± 45° along track. The detailed comparison of Formosat-2 with other similar sensors, including the multi-spectral bands and imaging repeat period, can be found in table I in Liu et al. (2007). To support IPY 2007–08, the National Space Organization (NSPO) of Taiwan launched a Polar Imaging Campaign (PIC) in March 2006. Up to September 2007, a total of 1 131 624 km2 in the North Polar Region and a total of 57 408 km2 in the South Polar Region had been imaged by Formosat-2. All Formosat-2 images taken during the NSPO PIC are available from the authors.
Mammalian aquaporins: diverse physiological roles and potential clinical significance
Authors: Verkman A. S.
Published: May 2008

Aquaporins have multiple distinct roles in mammalian physiology. Phenotype analysis of aquaporin-knockout mice has confirmed the predicted role of aquaporins in osmotically driven transepithelial fluid transport, as occurs in the urinary concentrating mechanism and glandular fluid secretion. Aquaporins also facilitate water movement into and out of the brain in various pathologies such as stroke, tumour, infection and hydrocephalus. A major, unexpected cellular role of aquaporins was revealed by analysis of knockout mice: aquaporins facilitate cell migration, as occurs in angiogenesis, tumour metastasis, wound healing, and glial scar formation. Another unexpected role of aquaporins is in neural function – in sensory signalling and seizure activity. The water-transporting function of aquaporins is likely responsible for these roles. A subset of aquaporins that transport both water and glycerol, the ‘aquaglyceroporins’, regulate glycerol content in epidermal, fat and other tissues. Mice lacking various aquaglyceroporins have several interesting phenotypes, including dry skin, resistance to skin carcinogenesis, impaired cell proliferation, and altered fat metabolism. The various roles of aquaporins might be exploited clinically by development of drugs to alter aquaporin expression or function, which could serve as diuretics, and in the treatment of brain swelling, glaucoma, epilepsy, obesity and cancer.
Origin of the 100,000‐year timescale in Antarctic temperatures and atmospheric CO2
Authors: Toggweiler J. R.
Published: May 2008

A new mechanism is proposed to explain the 100,000‐year timescale for variations in Antarctic temperatures and atmospheric CO2 over the last 650,000 years. It starts with fluctuations in the oceanic overturning around Antarctica that release CO2 up to the atmosphere or trap it in the deep ocean. Every 50,000 years one of these fluctuations coincides with a changeover in the burial of CaCO3 in the deep ocean. The changeover alters the atmospheric pCO2 in a way that augments the tendency of the overturning. The augmented overturning then enhances the tendency of the CaCO3 burial, which augments the overturning, etc. In this way, an individual random fluctuation becomes one of the big transitions seen in the Antarctic ice cores. Alternating transitions toward the warm and cold states every 50,000 years produce the 100,000‐year timescale. The 50,000‐year time interval is set by the turnover time for CO3= ions in the ocean with respect to the CO2‐induced weathering of silicate rocks and the burial of CaCO3 on the seafloor.
Historical records of atmospheric Pb deposition in four Scottish ombrotrophic peat bogs: An isotopic comparison with other records from western Europe and Greenland
Authors: Cloy J. M. , Farmer J. G. , Graham M. C. , MacKenzie A. B. , Cook G. T.
Published: May 2008

Cores collected from ombrotrophic peat bogs in west central, east central, northeast and southwest Scotland were dated (14C, 210Pb) and analyzed (ICP‐OES, ICP‐MS) to derive and compare their historical records of atmospheric anthropogenic Pb deposition over the past 2500 years. On the basis of Pb isotopic composition (e.g., 206Pb/207Pb), clear indications of Pb contamination during the pre‐Roman/Roman, post‐Roman and medieval periods were attributed to the mining and smelting of Pb ores from Britain and elsewhere in Europe. Between the 17th and early 20th centuries, during the industrial period, the mining and smelting of indigenous Scottish Pb ores were the most important sources of anthropogenic Pb deposition at three of the sites. In contrast, at the most southerly site, influences from the use of both British Pb ores and imported Australian Pb ores (in more southern parts of Britain) since the late 19th century were evident. At each of the sites, Australian‐Pb‐influenced car exhaust emissions (from the 1930s to late 1990s), along with significant contributions from coal combustion (until the late 1960s and onset of the postindustrial period), were evident. Atmospheric anthropogenic Pb deposition across Scotland was greatest (∼10 to 40 mg m−2 a−1) between the late 1880s and late 1960s, increasing southward, declining to 0.44 to 5.7 mg m−2 a−1 by the early 2000s. The records from four peat bogs extend knowledge of the chronology of atmospheric Pb deposition trends across the northern hemisphere, there being general agreement with other environmental archive records from not only Scotland but also other countries in western Europe and Greenland. Nevertheless, during all periods investigated here, the isotopic composition of atmospheric Pb deposition across western Europe and Greenland exhibited variations in the relative importance of different sources of anthropogenic Pb, as well as some differences in timings and magnitudes of anthropogenic Pb contamination, arising from variations in local and regional sources of Pb deposition and possibly climatic regimes.
Global distribution and interannual variations of mesospheric and lower thermospheric neutral wind diurnal tide: 2. Nonmigrating tide
Authors: Wu Q. , Ortland D. A. , Killeen T. L. , Roble R. G. , Hagan M. E. , Liu H.‐L. , Solomon S. C. , Xu Jiyao , Skinner W. R. , Niciejewski R. J.
Published: May 2008

On the basis of the TIDI mesospheric and lower thermospheric neutral wind observations from 2002 (March) to 2007 (June), we analyze the interannual variations of nonmigrating diurnal tides from eastward zonal wave number 3 (E3) to westward zonal wave number 3 (W3). We focus on possible QBO‐related variations in these nonmigrating diurnal tide components. We found: (1) a strong reverse QBO effect on the W2 meridional diurnal tide in the September equinox and the December solstice, which suggests a W2 source of nonlinear interaction between planetary wave 1 and the migrating diurnal tide; (2) the QBO effect on the peak height during the June solstice on the E3 zonal diurnal tide; (3) several nonmigrating tide components (E3, E2, E1, W3 meridional, and W3 zonal) with similar eastward phase QBO enhancement during the March equinox to the migrating diurnal tide, although to a lesser degree from 2002 to 2005; (4) the QBO effects, in some cases, during 2006 and 2007 are either less or opposite those observed between 2002 and 2005.
Observed physical and environmental causes of scatter in whitecap coverage values in a fetch‐limited coastal zone
Authors: Callaghan Adrian H. , Deane Grant B. , Stokes M. Dale
Published: May 2008

Meteorological and oceanographic data along with sea surface images were recorded at a fetch‐limited coastal site to investigate the effect of physical and environmental conditions on whitecap coverage W. An automated image‐processing technique allowed over 100,000 images to be analyzed for W. Data analysis showed that many processes influenced W. The presence of tidal currents appeared to have augmented values of W under certain specific conditions. Analysis of wave spectra indicated the ubiquitous presence of swell propagating northward. Scatter in W was markedly absent in mixed seas when the spectral intensity of the wind waves was of the same order of magnitude as the spectral intensity of the swell waves. Swell‐dominated seas introduced much more scatter in W. W was approximately one third lower in swell‐dominated seas than in mixed seas. Specifically, steep swell waves (steepness values greater than 0.01) that propagated opposite to wind wave direction appeared to have reduced W at wind speeds below approximately 7.5 m s−1, but this effect needs more investigation. The coastal site enabled the possibility of investigating physical and environmental effects on W that would otherwise have been more difficult to observe in the open ocean.
Dielectric properties of the Martian south polar layered deposits: MARSIS data inversion using Bayesian inference and genetic algorithm
Authors: Zhang Zhenfei , Hagfors Tor , Nielsen Erling , Picardi Giovanni , Mesdea Arturo , Plaut Jeffrey J.
Published: May 2008

Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) has offered abundant data, which have been used to estimate dielectric properties of the south polar layered deposits (SPLD) of Mars. This paper presents a new way to invert the data to estimate the dielectric properties of the SPLD. A total of 4364 measurements were analyzed. The received radar signals are controlled by the physical properties of the SPLD and its basal layer and in addition by a number of factors including the transmitted wave properties, the satellite height, and the atmosphere/ionosphere environments. The received signals may also be influenced by surface clutter. Most of these factors are variable. This complexity causes the inversion to be difficult. To carry out the inversion, it is therefore essential to define a reasonably simple model for the physics of the surface/subsurface layers where the radar signal is reflected. The top and bottom interfaces of the SPLD are observed by MARSIS as two reflection peaks of the radar signals. The intensity ratio between the two reflection peaks is observed to be a function of the time difference separating the two peaks. By modeling this dependency, the influences of the satellite position and the atmosphere/ionosphere environments are canceled. This is a major step toward carrying out the inversion. Nevertheless, the inverse problem remains ill‐posed and highly nonlinear. Bayesian inference is employed to deal with the ill‐posed aspect of the inversion, and genetic algorithm is introduced to deal with the nonlinearity. It is concluded that the most probable value of the relative dielectric constant of the SPLD lies in 3.0–5.0, conductivity 1.0–2.0 × 10−6 S/m, and the relative dielectric constant of the basal layer is 7.5–8.5 (The basal layer conductivity is assumed to be 1.0 × 10−7 S/m.) These results support a suggestion that the SPLD are water ice/dust mixtures with dust content varying from 0 to more than 75%.
Wind tunnel simulation of the three‐dimensional airflow patterns around shrubs
Authors: Dong Zhibao , Luo Wanyin , Qian Guangqiang , Lu Ping
Published: May 2008

Dunes formed around vegetation such as shrubs are common in arid and semiarid regions and some coastal regions. Understanding their dynamics requires insights into the airflow patterns around shrubs. Thus, we analyzed the horizontal and vertical flow patterns around model shrubs using wind measurements obtained by particle image velocimetry in a scaled wind tunnel simulation. Flow patterns around shrubs were complicated by the presence of bleed flows and displaced flows. Below a critical shrub density (between 0.05 and 0.08), bleed flow is dominant. The flows separate in both horizontal and vertical planes when the shrub density equals or exceeds this critical density, resulting in reverse cells in the lee of shrubs. The horizontal reverse cells are characterized by two symmetrical, opposing reverse eddies, whereas the vertical reverse cells form a single eddy. The positions of the reverse cells shift in response to changes in shrub density, reflecting the interaction between bleed flow and reverse flow. The parameters of horizontal reverse cells are functions of shrub density and wind velocity. Parameters of vertical reverse cells change mainly with respect to shrub density and vary only slightly with wind velocity. The lengths of the horizontal and vertical reverse cells are correlated, reflecting interactions between them. Field experiments on dune morphology will be required to relate these airflow patterns to dune development.
Robustness in design and background variations in metamaterial/plasmonic cloaking
Authors: Alù Andrea , Engheta Nader
Published: May 2008

Here we discuss our recent numerical results concerning the robustness of the scattering cancellation effect produced by a plasmonic cloak with near‐zero permittivity and correspondingly negative polarizability. Being based on an integral effect and on an intrinsically nonresonant phenomenon, we show how variations of the geometrical parameters of the design and changes in the background do not sensibly affect the invisibility properties of the plasmonic/metamaterial cloak. Design examples are presented and discussed in order to highlight this robustness and to provide some insights into this cloaking phenomenon, different from other cloaking techniques recently presented in the literature.
Using operationally synthesized multiple‐Doppler winds for high resolution horizontal wind forecast verification
Authors: Bousquet Olivier , Montmerle Thibaut , Tabary Pierre
Published: May 2008

The potential value of operational Doppler radar networks for high resolution wind forecast verification is investigated through comparing wind outputs of the cloud resolving model AROME against newly available operational multiple‐Doppler winds in northern France. Quantitative comparisons of radar and model winds for a 16‐h frontal precipitation event show good agreement, with differences in wind speed (resp. direction) generally comprised between ±2.5 m.s−1 (resp. ±15°). Power spectra deduced from the scale decomposition of radar and model outputs also show good agreement through all scales. The method is also applied to validate the divergence structures as analyzed by AROME's 3Dvar assimilation system that considers, among a comprehensive set of observation types, the same radial velocities than those considered in the wind retrieval.
Quasielastic and inelastic neutron scattering study of methyl group rotation in solid and liquid pentafluoroanisole and pentafluorotoluene
Authors: Smuda Christoph , Gemmecker Gerd , Unruh Tobias
Published: May 2008

The rotational motion of the methyl group in pentafluoroanisole (PFA) and in pentafluorotoluene (PFT), respectively, was investigated by quasielastic neutron scattering (QENS). For solid PFA, the rotation can be described by a model for uniaxial rotational jumps between three equidistant sites on a circle. Similar to the molecular structure of α-toluene, two nonequivalent methyl groups in the unit cell with two different rotational barriers were found for solid PFT. From the analysis of the quasielastic scattering, the activation energies were determined. The barrier heights could be evaluated from bands in the inelastic part of the spectra. The methyl group dynamics in the liquid state is evaluated for both substances using different scattering functions, which are discussed. An empirical model for the description of the contribution of methyl groups in liquids of small organic molecules to the QENS spectra is presented. It is demonstrated that the process of methyl group rotation in the liquid phase is nearly free of a barrier.
Super critical thickness SiGe-channel heterostructure p-type metal-oxide-semiconductor field-effect transistors using laser spike annealing
Authors: Ní Chléirigh Cáit , Wang XiaoRu , Rimple Gana , Wang Yun , David Theodore N. , Canonico Michael , Hoyt Judy L.
Published: May 2008

Strained Si/strained Si0.3Ge0.7/relaxed Si0.7Ge0.3 heterostructure p-type metal-oxide-semiconductor field-effect transistors (MOSFETs) with high mobility and low leakage are demonstrated using laser spike annealing, despite a strained Si0.3Ge0.7 channel thickness that is two times the equilibrium critical thickness. Measured hole mobility is enhanced four times for Si0.3Ge0.7 channel MOSFETs relative to Si control devices, at an inversion charge density of 1013cm−2. For supercritical thickness strained SiGe channel films, the use of laser spike annealing allows source/drain annealing at significantly higher temperatures than is possible with rapid thermal annealing (e.g., 975 versus 800°C), while achieving superior leakage characteristics. For laser spike annealing temperatures above 1000°C, mobility is found to degrade due to partial relaxation and dislocation formation in the Si0.3Ge0.7 channel.
To the kinetics of photoinduced volume changes in chalcogenide glasses
Authors: Lukacs Rozalia , Baranovskii Sergej D. , Thomas Peter , Gebhard Florian
Published: May 2008

Recent experimental data on the dynamics of photoinduced volume changes in chalcogenide glasses are analyzed within a simple phenomenological model. Both kinetics of the volume expansion under continuous irradiation and that of the relaxation after the illumination is switched off are considered. Comparison between theoretical results and experimental data provides a quantitative estimate of the local conversion rate of structural units responsible for the effect into the expanded states. Furthermore, this comparison shows that the conversion rate in a-As2Se3 is several times smaller than that in a-Se.
Superfluidity of He4 confined in nanoporous media
Authors: Shirahama K. , Yamamoto K. , Shibayama Y.
Published: May 2008

We have examined superfluid properties of He4 confined to a nanoporous Gelsil glass that has nanopores 2.5nm in diameter. The pressure-temperature phase diagram was determined by torsional oscillator, heat capacity, and pressure studies. The superfluid transition temperature Tc approaches zero at 3.4MPa, indicating a novel quantum superfluid transition. By heat capacity measurements, the nonsuperfluid phase adjacent to the superfluid and solid phases is identified to be a nanometer-scale, localized Bose condensation state, in which global phase coherence is destroyed. At high pressures, the superfluid density has a T-linear term, and Tc is proportional to the zero-temperature superfluid density. These results strongly suggest that phase fluctuations in the superfluid order parameter play a dominant role on the phase diagram and superfluid properties.
Konstantinov effect in helium II
Authors: Melnikovsky L. A.
Published: May 2008

The reflection of first and second sound waves by a rigid flat wall in helium II is considered. A nontrivial dependence of the reflection coefficients on the angle of incidence is obtained. Sound conversion is predicted at oblique incidence.
High-pressure Raman scattering study on zircon- to scheelite-type structural phase transitions of RCrO4
Authors: Long Y. W. , Yang L. X. , Yu Y. , Li F. Y. , Lu Y. X. , Yu R. C. , Liu Y. L. , Jin C. Q.
Published: May 2008

High-pressure Raman scattering experiments were performed on the zircon-type RCrO4 (R=Nd, Dy) compounds with the space group I41/amd by using diamond anvil cell techniques at room temperature. These two compounds exhibit similar Raman behaviors. Pressure-induced structural phase transitions were observed at the onset of 1.3 and 4.1 GPa for R=Nd and Dy, respectively. Moreover, pressure-released Raman spectra indicate that the structural transitions are irreversible. The high-pressure new phases were convincingly confirmed to be the scheelite structure in I41/a symmetry based on the same Raman vibrations between the pressure-released DyCrO4 and the scheelite-type DyCrO4 synthesized at 6 GPa and 450 °C. In addition, we also calculated the bulk moduli according to Errandonea’s method as well as the mode Grüneisen parameters of RCrO4.