bluuebunny/crossref_metadata_2025 huggingface dataset:
Recreational physical activity and survival among young women with breast cancer
Authors: Abrahamson Page E. , Gammon Marilie D. , Lund Mary Jo , Britton Julie A. , Marshall Stephen W. , Flagg Elaine W. , Porter Peggy L. , Brinton Louise A. , Eley J. William , Coates Ralph J.
Published: September 2006

BACKGROUND

Most epidemiologic studies report a reduced risk of developing breast cancer associated with higher levels of recreational physical activity, but little is known regarding its effect on prognosis.

METHODS

In this study, the authors investigated whether activity undertaken prior to diagnosis influenced breast cancer survival in a population‐based cohort. A follow‐up study was conducted among 1264 women ages 20 to 54 years who were diagnosed with invasive breast cancer between 1990 and 1992. Women in the study were interviewed within several months of diagnosis and were asked about their average frequency of moderate and vigorous activity at age 13 years, age 20 years, and during the year before diagnosis. With 8 to 10 years of follow‐up, all‐cause mortality status was determined by using the National Death Index (n= 290 deaths).

RESULTS

A modest reduction in the hazards ratio (HR) was observed for the highest quartile of activity in the year before diagnosis compared with the lowest quartile (stage‐adjusted and income‐adjusted HR, 0.78; 95% confidence interval [95% CI], 0.56–1.08). High activity was associated with a reduced HR among women who were overweight or obese at the time of diagnosis (HR, 0.70; 95% CI, 0.49–0.99) but not among ideal weight or underweight women (HR, 1.08; 95% CI, 0.77–1.52). A reduced HR was not evident for activity at age 13 years or 20 years or for average activity across the 3 periods studied.

CONCLUSIONS

The results of this study provided some suggestive evidence for a beneficial effect on survival of recreational physical activity undertaken in the year before diagnosis, particularly among women who are overweight or obese near the time of diagnosis. Cancer 2006. Published 2006 by the American Cancer Society.
Clinical outcome of anaplastic thyroid carcinoma treated with radiotherapy of once‐ and twice‐daily fractionation regimens
Authors: Wang Yongjin , Tsang Richard , Asa Sylvia , Dickson Brendan , Arenovich Tamara , Brierley James
Published: September 2006

BACKGROUND

The purpose was to assess local control, survival, and toxicity after radiotherapy in patients with anaplastic thyroid carcinoma, and to compare clinical outcomes between once‐daily and twice‐daily fractionation regimens.

METHODS

A retrospective review of patients with anaplastic thyroid carcinoma (n = 47) who underwent external beam radiotherapy from 1983 to 2004 was conducted. Twenty‐three patients underwent radical radiotherapy with a radiation dose >40 Gy, and 24 patients underwent palliative radiotherapy with a dose ≤40 Gy. Of radical radiotherapy, radiation was given with once‐daily (14 patients) or twice‐daily fractionation (9 patients; 1.5 Gy per fraction) to a total dose of 45–66 Gy. Most patients (37 patients; 78.7%) were followed to death.

RESULTS

The 6‐month local progression‐free rate in patients who underwent radical radiotherapy was 94.1%, significantly higher compared with palliative radiotherapy (64.6%; P = .02). The median actuarial overall survival was greater in patients with radical radiotherapy (11.1 months) compared with palliative radiotherapy (3.2 months; P < .0001). The median overall survival in patients with twice‐daily fractionation (13.6 months) was 3.3 months longer than patients treated with once‐daily fractionation (10.3 months), but the difference was not statistically significant (P = .3). For patients treated with twice‐daily fractionation, 3 patients had Grade 3 acute skin toxicity, and no patient had Grade 3 or higher esophageal toxicity.

CONCLUSIONS

Radiotherapy can result in local control of anaplastic thyroid carcinoma. A twice‐daily fractionation regimen is well tolerated and has a trend to longer survival, which deserves a larger study. Cancer 2006. © 2006 American Cancer Society.
Molecular symmetry and ferroelectricity in pure organic molecular crystals
Authors: Choudhury R. R. , Chitra R.
Published: September 2006

The molecular symmetry of all the existing organic ferroelectrics was analyzed with an intention to develop a criterion to search for new low molecular weight organic ferroelectric. We present here a summery of the analysis; it is conclude that in order to exhibit ferroelectricity in crystalline state the molecules should necessarily poses symmetry higher than C1, since this appears to be an important requirement to ensure reorientability of the electrical polarization of the crystals. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Square‐root domain wave filters
Authors: Psychalinos C.
Published: September 2006

In this paper the wave method is used for designing high‐order square‐root domain filters, which emulate the topology of the corresponding LC ladder prototypes. This is achieved by transposing the signal flow graph that corresponds to the wave equivalent of the elementary two‐port subnetwork in the linear domain to the corresponding one in the square‐root domain, by employing an appropriate set of complementary operators. As the equivalents of the other reactive elements are derived from the wave equivalent of the elementary subnetwork, by interchanging the terminals of the appropriate wave signals and/or using inverters, an advantage offered by the proposed technique is the modularity of the derived filter configurations. As an example, a fifth‐order lowpass square‐root domain wave filter was designed and its behaviour was studied through simulation results in order to demonstrate the validity of the proposed design technique. Copyright © 2006 John Wiley & Sons, Ltd.
Triethanolamine as an Efficient and Reusable Base, Ligand and Reaction Medium for Phosphane‐Free Palladium‐Catalyzed Heck Reactions
Authors: Li Hong Ji , Wang Lei
Published: September 2006

Triethanolamine was found to be an efficient and reusable base, ligand and reaction medium for phosphane‐free palladium‐catalyzed Heck reactions. The olefination of iodo‐ and bromoarenes generated the corresponding products in good to excellent yields in the presence of catalytic amounts of palladium acetate in triethanolamine without any additive. Moderate yields of the desired products were obtained with activated chloroarenes. In addition, triethanolamine could be recovered and recycled for five consecutive trials without significant loss of its reactivity. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Glutathione Peroxidase‐Based Amperometric Biosensor for the Detection of S‐Nitrosothiols
Authors: Musameh Mustafa , Moezzi Neda , Schauman Lisa M. , Meyerhoff Mark E.
Published: October 2006

A new biosensor is described for the detection of S‐nitrosothiols (RSNOs) based on their decomposition by immobilized glutathione peroxidase (GPx), an enzyme containing selenocysteine residue that catalytically produces nitric oxide (NO) from RSNOs. The enzyme is entrapped at the distal tip of a planar amperometric NO sensor. The new biosensor shows good sensitivity, linearity, reversibility, and response times towards various RSNO species in PBS buffer, pH 7.4 . In most cases, the response time is less than 5 min, and the response is linear up to 6 μM of the tested RSNO species. The lowest detection limit is obtained for S‐nitrosocysteine (CysNO), at approx. 0.2 μM. The biosensor's sensitivity is not affected by the addition of EDTA as a chelating agent; an advantage over other potential catalytic enzymes that contain copper ion centers, such as CuZn‐superoxide dismutase and xanthine oxidase. However, lifetime of the new sensor is limited, with sensitivity decrease of 50% after two days of use. Nonetheless, the new amperometric GPx based RSNO sensor could prove useful for detecting relative RSNO levels in biological samples, including whole blood.
Quantifying hillslope erosion rates and processes for a coastal California landscape over varying timescales
Authors: O'Farrell Colin R. , Heimsath Arjun M. , Kaste James M.
Published: September 2006

The Earth's surface erodes by processes that occur over different spatial and temporal scales. Both continuous, low‐magnitude processes as well as infrequent, high‐magnitude events drive erosion of hilly soil‐mantled landscapes. To determine the potential variability of erosion rates we applied three independent, field‐based methods to a well‐studied catchment in the Marin Headlands of northern California. We present short‐term, basin‐wide erosion rates determined by measuring pond sediment volume (40 years) and measured activities of the fallout nuclides 137Cs and 210Pb (40–50 years) for comparison with long‐term (>10 ka) rates previously determined from in situ‐produced cosmogenic 10Be and 26Al analyses. In addition to determining basin‐averaged rates, 137Cs and 210Pb enable us to calculate point‐specific erosion rates and use these rates to infer dominant erosion processes across the landscape. When examined in the context of established geomorphic transport laws, the correlations between point rates of soil loss from 137Cs and 210Pb inventories and landscape morphometry (i.e. topographic curvature and upslope drainage area) demonstrate that slope‐driven processes dominate on convex areas while overland flow processes dominate in concave hollows and channels. We show a good agreement in erosion rates determined by three independent methods: equivalent denudation rates of 143 ± 41 m Ma−1 from pond sediment volume, 136 ± 36 m Ma−1 from the combination of 137Cs and 210Pb, and 102 ± 25 m Ma−1 from 10Be and 26Al. Such agreement suggests that erosion of this landscape is not dominated by extreme events; rather, the rates and processes observed today are indicative of those operating for at least the past 10 000 years. Copyright © 2006 John Wiley & Sons, Ltd.
The ‘natural’ endpoint of dementia: death from cachexia or dehydration following palliative care?
Authors: Koopmans Raymond T. C. M. , van der Sterren Karin J. M. A. , van der Steen Jenny T.
Published: October 2006

Objectives

To investigate the causes of death in nursing home patients with dementia, and to compare causes of death in patients who survive until the final phase of dementia with those who die before reaching that phase, adjusted for potential confounders.

Design

Observational analysis of a cohort of patients with a prospective follow‐up.

Setting

Psychogeriatric nursing home ‘Joachim en Anna’ in Nijmegen, the Netherlands.

Participants

Eight hundred and ninety dementia patients admitted between 1980 and 1989. All patients were followed until death.

Measurements

The final phase of dementia was defined as total impairment on 20 items of a functional status questionnaire. Immediate causes of death (part 1a of the Dutch death certificate) were classified by the International Classification of Health Problems in Primary Care.

Results

The three most important reported immediate causes of death were cachexia/dehydration (35.2%), cardio‐vascular disorders (20.9%) and acute pulmonary diseases (20.1%), mainly pneumonia. Cachexia/dehydration was particularly common as a cause of death of patients who survived to the final phase (53.2%); survival to the final phase of dementia was an independent predictor of cachexia/dehydration as an immediate cause of death with reference to cardiovasculair disorders in multinomial regression adjusted for age at death, gender, and type of dementia.

Conclusion

Patients who survive to the final phase of dementia are more likely to die from cachexia or dehydration than those who die before. The findings contribute to a debate on what should be reported as the immediate cause of death in dementia including perspectives from a palliative care viewpoint. Copyright © 2006 John Wiley & Sons, Ltd.
Detecting and characterizing reactive metabolites by liquid chromatography/tandem mass spectrometry
Authors: Ma Shuguang , Subramanian Raju
Published: September 2006

Metabolic activation of a drug leading to reactive metabolite(s) that can covalently modify proteins is considered an initial step that may lead to drug‐induced organ toxicities. Characterization of reactive metabolites is critical to designing new drug candidates with an improved toxicological profile. High performance liquid chromatography (HPLC) coupled with mass spectrometry (MS) predominates over all analytical tools used for screening and characterization of reactive metabolites. In this review, a brief description of experimental approaches employed for assessing reactive metabolites is followed by a discussion on the reactivity of acyl glucuronides and acyl coenzyme A thioesters. Techniques for high‐throughput screening and quantitation of reactive metabolite formation are also described, along with proteomic approaches used to identify protein targets and modification sites by reactive metabolites. Strategies for dealing with reactive metabolites are reviewed. In conclusion, we discuss the challenges and future needs in this field of research. Copyright © 2006 John Wiley & Sons, Ltd.
Micromechanical Testing of Individual Collagen Fibrils
Authors: van der Rijt Joost A. J. , van der Werf Kees O. , Bennink Martin L. , Dijkstra Pieter J. , Feijen Jan
Published: September 2006

Summary: A novel method based on AFM was used to attach individual collagen fibrils between a glass surface and the AFM tip, to allow force spectroscopy studies of these. The fibrils were deposited on glass substrates that are partly coated with Teflon AF®. A modified AFM tip was used to accurately deposit epoxy glue droplets on either end of the collagen fibril that cross the glass‐Teflon AF® interface, as to such attach it with one end to the glass and the other end to the AFM tip. Single collagen fibrils have been mechanically tested in ambient conditions and were found to behave reversibly up to stresses of 90 MPa. Within this regime a Young's modulus of 2–7 GPa was obtained. In aqueous media, the collagen fibrils could be tested reversibly up to about 15 MPa, revealing Young's moduli ranging from 0.2 to at most 0.8 GPa.

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Polynomial stability of operator semigroups
Authors: Bátkai András , Engel Klaus‐Jochen , Prüss Jan , Schnaubelt Roland
Published: September 2006

We investigate polynomial decay of classical solutions of linear evolution equations. For bounded strongly continuous semigroups on a Banach space this property is closely related to polynomial growth estimates of the resolvent of the generator. For systems of commuting normal operators polynomial decay is characterized in terms of the location of the generator spectrum. The results are applied to systems of coupled wave‐type equations. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Transition of nuclear proteins and chromatin structure in spermiogenesis of Sepia officinalis
Authors: MartÍnez‐Soler F. , Kurtz K. , Ausió J. , Chiva M.
Published: September 2006

During spermiogenesis of Sepia officinalis histones are directly substituted by a molecule of precursor protamine, which is later transformed into the protamine through a deletion of the amino terminal end. In the present work, it is shown that the pattern of spermiogenic chromatin condensation consists of a phase of “patterning” and a phase of “condensation.” In the phase of patterning, three structural remodelings are produced in the chromatin structure: [somatic‐like chromatin → 18 nm granules → 25 nm fibers → 44 nm fibers]. The first remodeling of the chromatin into granules of 18 nm takes place without the entrance of specific proteins in the spermiogenic nuclei. The second remodeling [granules of 18 nm → fibers of 25 nm] is due to the entrance of the precursor protamine and its interaction with the DNA–histone complex. The third remodeling [fibers of 25 nm → fibers of 44 nm] occurs simultaneously with the disappearance of histones from the chromatin. In the phase of condensation, the fibers of 44 nm coalesce among themselves to form progressively larger aggregates of chromatin. In this phase there are no substantial variations in the nuclear proteins, so that the condensation of the chromatin must respond to posttranscriptional changes of the precursor protamine (dephosphorylation, deletion of the amino‐terminal end). Mol. Reprod. Dev. © 2006 Wiley‐Liss, Inc.
Regulation of MMP‐9 expression and activity in the mouse uterus by estrogen
Authors: Zhang Xuan , Christenson Lane K. , Nothnick Warren B.
Published: September 2006

Matrix metalloproteinases (MMPs) are spatiotemporally expressed in the uterus across normal estrous and menstrual cycles and are known to participate in the extensive endometrial tissue remodeling. MMP‐9/gelatinase B is one of the major MMPs found in the uterus that modulates uterine biology during various reproductive processes. Although it seems that uterine MMP‐9 is under ovarian steroid hormonal control, there are conflicting reports regarding steroidal hormonal regulation of MMP‐9 expression, and there is little information on the effects of estrogen in vivo in this respect. We therefore examined the steroidal regulation of MMP‐9 within the mouse uterus. Female mice (2–3 months old) were ovariectomized and treated with estradiol‐l7β (E2) or E2 + progesterone (P4) and uterine gelatinase activity and expression were determined. Gelatin zymography revealed that E2 alone or in combination with P4 increased MMP‐9 activation, whereas Northern analysis showed that E2 decreased MMP‐9 steady state mRNA expression and an estrogen receptor antagonist ICI‐182, 780 blocked this effect. In contrast, uterine MMP‐2 expression and activity were not affected by steroidal treatments. Pretreatment with a transcription inhibitor actinomycin D or translation inhibitor cycloheximide indicates that E2 regulates uterine MMP‐9 at multiple points, involving transcriptional and posttranscriptional control as well as modulation of inhibitor activities. Collectively, these data suggest that E2 regulates uterine MMP‐9 expression and activity in vivo via a complex mechanism. This estrogen regulation of MMP‐9 activity may play an important role in uterine tissue remodeling. Mol. Reprod. Dev. © 2006 Wiley‐Liss, Inc.
Characterization and differential expression of vascular endothelial growth factor isoforms and receptors in swine corpus luteum throughout estrous cycle
Authors: Ribeiro Luciana Andrea , Bacci Maria Laura , Seren Eraldo , Tamanini Carlo , Forni Monica
Published: September 2006

Corpus luteum (CL) undergoes growth and regression during each estrous cycle; these processes are accompanied by growth and regression of the luteal vascular bed. Vascular endothelial growth factor (VEGF) is the main regulator of angiogenesis, inducing endothelial cell proliferation, migration, vascular permeability, and vessel lumen formation. VEGF presents several isoforms that are produced by alternative splicing of the same mRNA transcript. We determined by real time RT‐PCR the expression patterns of VEGF isoform and receptor mRNAs, as well as the VEGF protein levels in pig CL throughout a whole estrous cycle. Four novel VEGF isoforms (VEGF144, VEGF147, VEGF182, and VEGF164b) were found for the first time in swine and the seven identified isoforms can be grouped in four different patterns of expression. The most expressed splice variants were VEGF120 and VEGF164. All isoforms showed their highest mRNA levels in newly formed CLs (day 1), followed by a decrease during mid‐late luteal phase (days 10–17), except for VEGF182, VEGF188 and VEGF144 that showed a differential regulation during late luteal phase (day 14) or at luteolysis (day 17). VEGF protein levels paralleled the most expressed and secreted VEGF120 and VEGF164 isoforms. The VEGF receptors mRNAs showed a different pattern of expression in relation to their ligands, increasing between day 1 and 3 and gradually decreasing during the mid‐late luteal phase. The differential regulation of VEGF isoforms may suggest specific physiological roles for some of them, particularly in angioregression occurring during the apoptotic structural luteolysis. Mol. Reprod. Dev. © 2006 Wiley‐Liss, Inc.
Plectin defects in epidermolysis bullosa simplex with muscular dystrophy
Authors: McMillan J.R. , Akiyama M. , Rouan F. , Mellerio J.E. , Lane E.B. , Leigh I.M. , Owaribe K. , Wiche G. , Fujii N. , Uitto J. , Eady R.A.J. , Shimizu H.
Published: September 2006

Epidermolysis bullosa simplex with muscular dystrophy (EBS‐MD, MIM 226670) is caused by plectin defects. We performed mutational analysis and immunohistochemistry using EBS‐MD (n = 3 cases) and control skeletal muscle to determine pathogenesis. Mutational analysis revealed a novel homozygous plectin‐exon32 rod domain mutation (R2465X). All plectin/HD1‐121 antibodies stained the control skeletal muscle membrane. However, plectin antibodies stained the cytoplasm of type II control muscle fibers (as confirmed by ATPase staining), whereas HD1‐121 stained the cytoplasm of type I fibers. EBS‐MD samples lacked membrane (n = 3) but retained cytoplasmic HD1‐121 (n = 1) and plectin staining in type II fibers (n = 3). Ultrastructurally, EBS‐MD demonstrated widening and vacuolization adjacent to the membrane and disorganization of Z‐lines (n = 2 of 3) compared to controls (n = 5). Control muscle immunogold labeling colocalized plectin and desmin to filamentous bridges between Z‐lines and the membrane that were disrupted in EBS‐MD muscle. We conclude that fiber‐specific plectin expression is associated with the desmin‐cytoskeleton, Z‐lines, and crucially myocyte membrane linkage, analogous to hemidesmosomes in skin. Muscle Nerve, 2006
Down‐regulation of torp4a, encoding the Drosophila homologue of torsinA, results in increased neuronal degeneration
Authors: Muraro Nara I. , Moffat Kevin G.
Published: September 2006

Early‐onset torsion dystonia is a dominant motor disorder linked to mutations in torsinA. TorsinA is weakly related to a superfamily of chaperone‐like proteins. The function of the torsin group remains largely unknown. Here we use RNAi and over‐expression to analyze the function of torp4a, the only Drosophila torsin. Targeted down‐regulation in the eye causes progressive degeneration of the retina. Conversely, over‐expression of torp4a protects from age‐related degeneration. In the retinas of young animals, a correlation with the lysosome‐related organelle, the pigment granule, is also observed. Lowering torp4a causes an increase in pigment granules, while over‐expression causes loss of granules. We have performed a screen for genetic interactors of torp4a identifying a number mutants, including two members of the AP‐3 complex. Other genetic interactors found included genes related to actin and myosin function. Our findings implicate the Drosophila torsin, torp4a, to function with molecules consistent with already predicted roles in the endoplasmic reticulum/nuclear envelope compartment, and have identified potential new interactions with AP‐3 like components. © 2006 Wiley Periodicals, Inc. J Neurobiol, 2006
Breeding status affects motoneuron number and muscle size in naked mole‐rats: Recruitment of perineal motoneurons?
Authors: Seney Marianne , Goldman Bruce D. , Forger Nancy G.
Published: September 2006

Naked mole‐rats live in large colonies and exhibit a strict reproductive hierarchy. Each colony has one breeding female and one to three breeding males; all other individuals are nonreproductive subordinates. Subordinates show a remarkable lack of sex differences in behavior and anatomy, but can become reproductive if removed from the colony. We recently reported that the striated perineal muscles and their innervating motoneurons, which are sexually dimorphic in all other mammals examined to date, are not dimorphic in subordinate naked mole‐rats. Here we asked whether sexual differentiation of this neuromuscular system occurs when a subordinate becomes a breeder. The size and number of cells within Onuf's nucleus (homologue of the rat spinal nucleus of the bulbocavernosus) as well as perineal muscle volume were examined in subordinate and breeding naked mole‐rats of both sexes. Sex differences in perineal motoneurons were not observed, regardless of social status. To our surprise, however, counts of motoneurons in Onuf's nucleus were increased ∼30% in breeders of both sexes. This was accompanied by a reciprocal decrease in cells in Onuf's nucleus that were characterized by small soma size, and lacked a clear nucleus or nucleolus. Although not exhibiting typical motoneuron morphology, some of these small cells were positive for the motoneuron marker, SMI‐32. The neuronal changes correlate with increased perineal muscle volumes in breeders. We propose that small, relatively undifferentiated cells are recruited to the pool of large Onuf's nucleus motoneurons when subordinate naked mole‐rats become breeders. © 2006 Wiley Periodicals, Inc. J Neurobiol, 2006
Fabrication of high‐performance, gradient‐refractive‐index plastic rods with surfmer‐cluster‐stabilized nanoparticles
Authors: Liu Jui‐Hsiang , Yang Po‐Chih , Chiu Yi‐Hong
Published: September 2006

A novel method was developed with surfmer‐cluster‐stabilized silver nanoparticles to prepare high‐performance, gradient‐refractive‐index (GRIN) plastic rods based on methyl methacrylate. To fabricate the GRIN plastic rods, a novel polymerizable surfactant (surfmer) of 4‐(11‐acryloxyundecyloxy)benzoic acid (AUBA) was synthesized. Silver nanoparticles were prepared with a reverse micelle method in the presence of the novel surfmer. During the fabrication of the silver nanoparticles, the sodium salt of AUBA was formed. GRIN plastic rods were fabricated through centrifugal polymerization and then were heat‐treated at 100 °C under 0.1 Torr for 24 h to remove residual monomers and water. The distribution of the surfmer‐cluster‐stabilized nanoparticles inside the plastic rods was studied with transmission electron microscopy (TEM). The real‐image transmission through the fabricated rods was also confirmed. The results obtained in this investigation suggested that the control of the distribution of surfmer‐cluster‐stabilized nanoparticles could be used to fabricate GRIN rods. Furthermore, the existence of the crosslink‐like surfmers increased the thermal stability of the plastic rods. The GRIN distribution of the rods was established by the dispersion of nanoparticles inside the plastic rods through TEM analysis, refractive‐index analysis, and real‐image transmission. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5933–5942, 2006
Cyclic insulin‐regulated aminopeptidase (IRAP)/AT4 receptor ligands
Authors: Axén Andreas , Lindeberg Gunnar , Demaegdt Heidi , Vauquelin Georges , Karlén Anders , Hallberg Mathias
Published: September 2006

The angiotensin IV receptor (AT4 receptor) is the insulin‐regulated aminopeptidase enzyme (IRAP, EC 3.4.11.3). This membrane‐spanning enzyme belongs to the M1 family of zinc‐dependent metallo‐peptidases. It has been proposed that AT4 receptor ligands exert their physiological effects by binding to the active site of IRAP and thereby inhibiting the catalytic activity of the enzyme. The biological activity of a large series of linear angiotensin IV analogs was previously disclosed. Herein, the synthesis and biological evaluation of a series of angiotensin IV analogs, encompassing macrocyclic ring systems of different sizes, are presented. It is demonstrated that disulfide cyclizations of angiotensin IV can deliver ligands with high IRAP/AT4 receptor affinity. One ligand, with an 11‐membered ring system (4), inhibited human IRAP and aminopeptidase N (AP‐N) activity with similar potency as angiotensin IV but was considerably more stable than angiotensin IV toward enzymatic degradation. The compound provides a promising starting point for further optimization toward more drug‐like derivatives. The cyclic constrained analogs allowed us to propose a tentative bioactive conformation of angiotensin IV and it seems that the peptide adopts an inverse γ‐turn at the C‐terminal. Copyright © 2006 European Peptide Society and John Wiley & Sons, Ltd.
FEM modelling of surface acoustic wave in diamond layered structure
Authors: Le Brizoual L. , Sarry F. , Moreira F. , Elmazria O.
Published: September 2006

This paper describes a general finite element method (FEM) for the AC steady state analysis of two‐dimensional piezoelectric devices. The method is applied to a diamond based surface acoustic wave (SAW) layered structure. We determined the penetration depth of the elastic waves corresponding to ZnO layer of 1 µm thick and spatial periodicity of 4 µm. The structure admittance response shows six peaks corresponding to the mode 0, 1 and 2. The penetration depth in diamond is around 8 µm except for the mode 2 where it reaches 12 µm. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
First‐principles characterization of amorphous carbon nitride systems: structural and electronic properties
Authors: Titantah J. T. , Lamoen D.
Published: September 2006

A series of carbon nitride structures have been generated, by using a classical potential in a Metropolis Monte Carlo liquid quench procedure. The resulting structures are relaxed further using the density functional theory approach. Structures are generated for various mass densities and varying N/C ratio so that all possible C–N bonding configurations are produced. Structural analysis of the equilibrated structures are performed and the effect of nitrogen inclusion on the formation of curved carbon systems is evidenced. Density of states and energy‐loss near‐edge structure calculations show that nitrogen incorporation modifies the valence and conduction bands of amorphous carbon (a‐C). X‐ray photoelectron spectroscopy (XPS) calculations within the first‐principles methodology are also performed on the generated a‐C nitride systems. Depending on the carbon bonding configuration, the carbon 1s energies are found to vary from 283 eV to 288 eV while those of nitrogen are found to range from 397 eV to 402 eV. The experimentally observed N 1s XPS features of a‐C nitride systems are correlated with the nitrogen bonding state with carbon, the degree of delocalization of the nitrogen lone pair and the C–N bond length. In particular, our calculations support the interpretation of the N 1s feature at an energy of about 398.4 eV to two‐coordinated N atoms whose immediate neighbors enhance a delocalization of the N lone pair of electrons. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Acceptor compensation by dislocations related defects in boron doped homoepitaxial diamond films from cathodoluminescence and Schottky diodes current voltage characteristics
Authors: Muret P. , Wade M.
Published: September 2006

This document shows that new electrically active defects can develop in the homoepitaxial layer grown on Ib diamond substrates, related to the increase of the dislocation density. Deep centres, which are able to compensate the boron acceptors, specially when the growth process allows boron incorporation below 1015 cm–3 like achieved in the samples, are identified after heating in an inert gas ambient both from photo‐induced current transient spectroscopy (PICTS) and changes in Schottky diode current–voltage characteristics. Cathodoluminescence spectra are used to monitor the bands and excitonic lines, some of them being specific of dislocations. A correlation is demonstrated between the onset of properties characteristic of a compensated semiconductor and the increase of signals associated to dislocations in cathodoluminescence spectra. These modifications are thermally driven only when the samples are laid on a heating holder immerged in an inert gas, suggesting that a temperature gradient induced an additional stress which finally led to plastic relaxation of the tensile strain in the homoepitaxial layer by an increase of the dislocation density. New deep centres being simultaneously created in this degradation process, the problem of overcoming the onset of these defects for implementing high voltage devices is discussed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photoelectron emission from diamond
Authors: Takeuchi D. , Nebel C. E. , Yamasaki S.
Published: September 2006

From total photoyield spectroscopy (TPYS) experiments we derive information about electron generation and emission properties in diamond. From the spectra, dynamic change between negative and positive electron affinities are detected. Temperature dependent TPYS experiments reveal a decrease of the optical band gap of diamond at high temperature. In addition, we show that a low density of boron can be detected, combining TPYS and cathodoluminescence experiments. We discuss properties of partially hydrogen terminated diamond surfaces, which are realized by in‐situ thermal evaporation of hydrogen with TPYS experiments, with respect to a variation of electron affinity affecting sub‐band and band gap excited electron emission properties. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Design of distributed controllers with constrained and noisy links
Authors: Jiang Shengxiang , Voulgaris Petros G.
Published: September 2006

In this paper we consider some design aspects of distributed controllers that guarantee a ℋ︁∞performance level. In particular, we consider two design problems. First, is the case where, without loss of generality, there are two distributed subcontrollers connected to a (generalized) plant and the interest is placed in minimizing the number of noise‐free (and dynamics free) communication channels between the subcontrollers needed to provide a given performance. The second is the case where, given a distributed controller designed in the first case, communication noise is present and we seek an optimal choice of the communication signals to guarantee a performance level while keeping the communication signal to noise power limited. We take a linear matrix inequality (LMI) approach to provide solution procedures to these problems and present examples that demonstrate their efficiency. Copyright © 2006 John Wiley & Sons, Ltd.
Collagen impairs glucocorticoid actions in airway smooth muscle through integrin signalling
Authors: Bonacci J V , Schuliga M , Harris T , Stewart A G
Published: September 2006

Background and purpose:

Airway wall remodelling in asthma is characterised by a number of structural changes, including an increase in the volume of airway smooth muscle (ASM), and the abundance of the extracellular matrix (ECM) protein, collagen, is increased. We have investigated the mechanism of collagen‐induced glucocorticoid resistance of proliferation, and migration of ASM.

Experimental approach:

ASM cultured from human airways has been seeded on to either type I monomeric collagen or a laminin pentapeptide, YIGSR. The role of α2β1 integrin in the collagen‐induced glucocorticoid resistance was investigated using a function blocking monoclonal antibody.

Key results:

Culture of ASM on collagen I, but not laminin, led to a greater proliferative response that was insensitive to regulation by dexamethasone (100 nM). The anti‐migratory effects of the glucocorticoid, fluticasone propionate (1 nM) were also impaired by contact of ASM with collagen. The impaired anti‐mitogenic action of dexamethasone was associated with a failure to reduce the levels of the rate‐limiting cell cycle regulatory protein, cyclin D1. When signalling through the α2β1 integrin was reduced, dexamethasone‐mediated reductions in proliferation and cyclin D1 levels were restored.

Conclusions and implications:

In the collagen‐rich microenvironment of the inflamed and fibrotic asthmatic airway, integrin/ECM interactions may contribute to glucocorticoid resistance.

British Journal of Pharmacology (2006) 149, 365–373. doi:10.1038/sj.bjp.0706881
The C‐terminus of murine S100A9 protein inhibits hyperalgesia induced by the agonist peptide of protease‐activated receptor 2 (PAR2)
Authors: Dale C S , Cenac N , Britto L R G , Juliano M A , Juliano L , Vergnolle N , Giorgi R
Published: September 2006

Background and purpose:

S100A9 protein induces anti‐nociception in rodents, in different experimental models of inflammatory pain. Herein, we investigated the effects of a fragment of the C‐terminus of S100A9 (mS100A9p), on the hyperalgesia induced by serine proteases, through the activation of protease‐activated receptor‐2 (PAR2).

Experimental approach:

Mechanical and thermal hyperalgesia induced by PAR2 agonists (SLIGRL‐NH2 and trypsin) was measured in rats submitted to the paw pressure or plantar tests, and Egr‐1 expression was determined by immunohistochemistry in rat spinal cord dorsal horn. Calcium flux in human embryonic kidney cells (HEK), which naturally express PAR2, in Kirsten virus‐transformed kidney cells, transfected (KNRK‐PAR2) or not (KNRK) with PAR2, and in mouse dorsal root ganglia neurons (DRG) was measured by fluorimetric methods.

Key results:

mS100A9p inhibited mechanical hyperalgesia induced by trypsin, without modifying its enzymatic activity. Mechanical and thermal hyperalgesia induced by SLIGRL‐NH2 were inhibited by mS100A9p. SLIGRL‐NH2 enhanced Egr‐1 expression, a marker of nociceptor activation, and this effect was inhibited by concomitant treatment with mS100A9p. mS100A9p inhibited calcium mobilization in DRG neurons in response to the PAR2 agonists trypsin and SLIGRL‐NH2, but also in response to capsaicin and bradykinin, suggesting a direct effect of mS100A9 on sensory neurons. No effect on the calcium flux induced by trypsin or SLIGRL in HEK cells or KNRK‐PAR2 cells was observed.

Conclusions and implications:

These data demonstrate that mS100A9p interferes with mechanisms involved in nociception and hyperalgesia and modulates, possibly directly on sensory neurons, the PAR2‐induced nociceptive signal.

British Journal of Pharmacology (2006) 149, 374–384. doi:10.1038/sj.bjp.0706884
Measurement of temperature-dependent defect diffusion in proton-irradiated GaN(Mg, H)
Authors: Fleming R. M. , Myers S. M.
Published: September 2006

Deuterated p-type GaN(Mg,H2) films were irradiated at room temperature with 1MeV protons to create native point defects with a concentration approximately equal to the Mg doping (5×1019cm−3). The samples were then annealed isothermally at a succession of temperatures while monitoring the infrared absorption due to the H local mode of the MgH defect. As the samples were annealed, the MgH absorption signal decreased and a new mode at slightly higher frequency appeared, which has been associated with the approach of a mobile nitrogen interstitial. We used the time dependence of the MgH absorption to obtain a diffusion barrier of the nitrogen interstitial in p-type GaN of 1.99eV. This is in good agreement with theoretical calculations of nitrogen interstitial motion in GaN.
Axial flow effects on the stability of circular Couette flow with viscous heating
Authors: Cotrell David L. , McFadden G. B.
Published: September 2006

We consider flow between concentric circular cylinders driven jointly by a constant axial pressure gradient and rotation of one or both cylinder walls. In this work we account for viscous heating effects with a temperature-dependent viscosity, and have computed critical values with a radius ratio η≡Ri∕Ro=0.827 and rotation rate ratio κ≡Ωo∕Ωi=0 as used in the recent zero axial flow experiments of White and Muller [J. Fluid Mech. 462, 133 (2002)], where Ri and Ro are the inner and outer cylinder radii, respectively, and Ωi and Ωo are the corresponding (signed) angular velocities. The effects of gravity are neglected, whereas conductivity, the volumetric coefficient of thermal expansion, density, and constant pressure specific heat are taken to be constant. The analysis extends previous results with no axial flow, and accounts for arbitrary disturbances of infinitesimal amplitude. Results show that over the entire range of axial flow rates considered, stability boundaries differ significantly from those found for the zero axial flow case. Consistent with the isothermal results of Cotrell, Rani, and Pearlstein [J. Fluid Mech. 509, 353 (2004)] and the nonisothermal results of Cotrell and McFadden [Physics of Fluids 17, 114102 (2005)], the critical disturbance is axisymmetric only over a finite range of Reynolds numbers beginning at zero, beyond which the critical disturbance becomes nonaxisymmetric.
Image reconstruction algorithms for inertial confinement fusion neutron imaging
Authors: Barrera Carlos A. , Morse Edward C. , Moran Michael J.
Published: October 2006

A neutron imaging system is required to diagnose ignition implosions at the National Ignition Facility. Such a system is required to be able to resolve features in the imploded target core as small as 5μm. The system will use a pinhole-camera-type geometry with a nonideal coded aperture and will employ image restoration techniques. The choice of image reconstruction method will be important in recovering the best possible source images from the recorded data. Monte Carlo transport simulations with MCNP5 make it possible to estimate the performance of the neutron imaging system based on calculated energy-dependent image edits of a failed inertial confinement fusion implosion. Simulations of the recorded neutron images include specific aperture designs, a pixelated energy- and time-dependent scintillator array, and an intensified gated charge coupled device camera for recording the images. An initial series of simulations used a source that was binned into 1MeV increments from 6to18MeV, an imaging aperture approximately 40cm from target chamber center, and a detector array at 40m, for a system magnification of around 100. A modified regularization method used the calculated point spread function of the overall system to deconvolve the simulated images. The results demonstrate the possibility that the imaging system can satisfy the resolution requirements and provide the desired images of the neutron emission source.
Rapid distortion analysis of homogeneous turbulence subjected to rotating shear
Authors: Girimaji Sharath S. , O’Neil J. R. , Yu Dazhi
Published: September 2006

We perform inviscid rapid distortion calculations of initially isotropic turbulence subject to unsteady shear. The mean strain-rate tensor is of constant magnitude but the eigendirections rotate at a uniform rate or frequency. When the forcing frequency is zero, constant-shear forcing is recovered. The results indicate that there are three distinct regimes of physical behavior for this kind of forcing: (1) at low frequencies, turbulence quickly becomes one-componential and fluctuation field attains statistical steady state; (2) at intermediate frequencies, kinetic energy exhibits sporadic growth spurts interspersed with the periods of no activity; and (3) at relatively high frequencies, kinetic energy evolution exhibits a purely periodic behavior. It is rather intriguing that turbulence decays at low frequencies but grows at intermediate frequencies of forcing. We investigate the physics underlying the observed behavior and examine the roles of production and pressure-strain correlation. Finally, a simple dynamical model that captures the observed regimes of behavior is proposed. In this model the different turbulence responses are reproduced by merely introducing different phase lags between applied strain and Reynolds stress.
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buffer layers by atomic layer deposition in Cu(In,Ga)Se2 based thin film solar cells: Band alignment and sulfur gradient
Authors: Platzer-Björkman C. , Törndahl T. , Abou-Ras D. , Malmström J. , Kessler J. , Stolt L.
Published: September 2006

Thin film solar cells with the structure sodalimeglass∕Mo∕Cu(In,Ga)Se2∕Zn(O,S)∕ZnO∕ZnO:Al are studied for varying thickness and sulfur content of the Zn(O,S) buffer layer. These Zn(O,S) layers were deposited by atomic layer deposition (ALD) at 120°C. Devices with no or small concentrations of sulfur in the buffer layer show low open-circuit voltages. This is explained by the cliff, or negative conduction-band offset (CBO), of −0.2eV measured by photoelectron spectroscopy (PES) and optical methods for the Cu(In,Ga)Se2 (CIGS)∕ZnO interface. Devices with ZnS buffer layers exhibit very low photocurrent. This is expected from the large positive CBO (spike) of 1.2eV measured for the CIGS∕ZnS interface. For devices with Zn(O,S) buffer layers, two different deposition recipes were found to yield devices with efficiencies equal to or above reference devices in which standard CdS buffer layers were used; ultrathin Zn(O,S) layers with S∕Zn ratios of 0.8–0.9, and Zn(O,S) layers of around 30nm with average S∕Zn ratios of 0.3. The sulfur concentration increases towards the CIGS interface as revealed by transmission electron microscopy and in vacuo PES measurements. The occurrence of this sulfur gradient in ALD-Zn(O,S) is explained by longer incubation time for ZnO growth compared to ZnS growth. For the Zn(O,S) film with high sulfur content, the CBO is large which causes blocking of the photocurrent unless the film is ultrathin. For the Zn(O,S) film with lower sulfur content, a CBO of 0.2eV is obtained which is close to ideal, according to simulations. Efficiencies of up to 16.4% are obtained for devices with this buffer layer.
Effects of surfactants Sb and Bi on the incorporation of zinc and carbon in III/V materials grown by organometallic vapor-phase epitaxy
Authors: Howard A. D. , Chapman D. C. , Stringfellow G. B.
Published: September 2006

The incorporation of both dopants and background impurities during the organometallic vapor phase epitaxial (OMVPE) growth of GaAs, GaInP, and GaP has been significantly altered by the use of the surfactants Sb and Bi. Sb and Bi are isoelectronic with the group V host elements, and so produce no independent doping. This paper demonstrates that the incorporation of Zn can be increased by an order of magnitude in GaP to a value of approximately 1020cm−3, the highest value reported to date. Additionally, these same surfactants lead to significant decreases in carbon contamination during growth. At high growth temperatures the reduction can be as large as 100× in GaP. The surfactants also result in marked decreases in autodoping due to S and Si from the substrate. A marker that may help identify the mechanism for these effects is H incorporation. Both Sb and Bi surfactants give rise to increased concentrations of H in the GaP layers. Similar effects are observed in GaInP. However, in GaAs, no H is detected in the layers. One possible explanation for these phenomena is that Sb or Bi increases the surface H concentration. The increased H would have two possible effects on the incorporation of dopants and impurities. (1) Passivation of the Zn acceptor by formation of a neutral Zn-H complex would lead to increased incorporation for thermodynamic reasons. (2) Allowing increased desorption of C, S, and Si from the surface by increased formation of volatile hydrides leads to decreased incorporation levels. These results suggest a simple and effective method of controlling the incorporation of dopant and impurity atoms by adding a minute amount of surfactant during OMVPE growth.
X-ray induced pinhole closure in point-projection x-ray radiography
Authors: Bullock A. B. , Landen O. L. , Blue B. E. , Edwards J. , Bradley D. K.
Published: September 2006

In pinhole-assisted point-projection x-ray radiography (or “backlighting”), pinholes are placed between the sample of interest and an x-ray source (or “backlighter”) to effectively limit the source size and hence improve the spatial resolution of the system. Pinholes are generally placed close to such x-ray backlighters to increase the field of view, leading to possible vaporization and pinhole closure due to x-ray driven ablation, thereby potentially limiting the usefulness of this method. An experimental study and modeling of time-dependent closure and resolution is presented. The pinhole closure time scale is studied for various pinhole sizes, pinhole-to-backlighter separations, and filtering conditions. In addition the time-dependent resolution is extracted from one-dimensional wire imaging prior to pinhole closure. Cylindrical hydrodynamic modeling of the pinhole closure shows reasonable agreement with data, giving us a predictive capability for pinhole closure in future experiments.