bluuebunny/crossref_metadata_2025 huggingface dataset:
The thermal degradation of poly(methyl methacrylate) nanocomposites with montmorillonite, layered double hydroxides and carbon nanotubes
Authors: Costache Marius C. , Wang Dongyan , Heidecker Matthew J. , Manias E. , Wilkie Charles A.
Published: January 2006

The thermal degradation of poly(methyl methacrylate) and its nanocomposite has been studied to determine if the presence of clays (anionic and cationic) or carbon nanotubes has an effect on the degradation pathway. Nanocomposite formation has been established by X‐ray diffraction and transmission electron microscopy, thermal degradation has been investigated by cone calorimetry and thermogravimetric analysis (TGA), and the products of degradation have been studied with TGA/FT‐IR and gas chromatography/mass spectrometry (GC/MS). There are no marked differences in the degradation products of the polymer and its nanocomposites, but the degradation of the nanocomposite occurs at higher temperatures. The most likely explanation is that poly(methyl methacrylate) degrades by only a single route, so the clay cannot promote one pathway at the expense of another. This observation bears important implications for the barrier mechanism, which is currently used to explain the reduction in the peak heat release rate of nanocomposites. Copyright © 2006 John Wiley & Sons, Ltd.
Evaluation of health status and health‐related quality of life in a cohort of Italian children following treatment for a primary brain tumor
Authors: Cardarelli Chiara , Cereda Cinzia , Masiero Lucia , Viscardi Elisabetta , Faggin Roberto , Laverda AnnaMaria , Bisogno Gianni , Perilongo Giorgio
Published: January 2006

Background

This study is a pilot experience aiming to investigate the compliance of an institutional cohort of Italian children treated for a malignant disease and their families in completing the health utilities index2, (HUI2) and the effectiveness of this measured in terms of their health status (HS) and health‐related quality of life (HRQL). It specifically, it aimed to compare the HS and the HRQL, as expressed by the HUI2 global utility score, in cohorts of patients who had brain tumors, extra‐cerebral solid tumors, or leukemia/lymphoma.

Procedure

Fifty survivors of brain tumors, between 8 and 30 years at the time of the assessment (“self”) and/or their parents (“proxy”), attending the Pediatric Oncology Out Patient clinic of Padua, Italy, completed the HUI2 questionnaire. Eighty‐nine children with acute leukemia/lymphoma and 74 with extra‐cerebral solid tumors and/or their parents were also assessed.

Results

The mean “self” and “proxy” HUI2 global utility scores in the brain tumor patients were 0.87 and 0.84, respectively, while in the cohorts of children with other solid tumors and leukemia/lymphoma, there were 0.94, 0.91, 0.96, and 0.92, respectively. The differences between the HUI2 global utility scores in the “self” and “proxy” assessment within each cohort of children were not statistically significant. In decreasing order of frequency, the attributes affected most commonly were: “emotion,” “pain,” “sensation,” and “cognition” both by “self” and “proxy” assessment.

Conclusions

In this Italian population of childhood cancer survivors the HUI2 questionnaire proved to be a user‐friendly tool, which provided information regarding HS and HRQL. A larger cohort of cancer children is needed to confirm the efficacy of the HUI2 questionnaire in distinguishing groups of children on this basis by disease category. Pediatric Blood Cancer © 2006 Wiley‐Liss, Inc.
TEM contrast of dissociated screw dislocations in silicon nearby a free surface
Authors: Boussaid Ahlem , Youssef Sami , Fnaiech Mustapha , Rouvière J.‐L. , Bonnet Roland
Published: January 2006

Dislocations are commonly analyzed by weak‐beam or high resolution transmission electron microscopy (TEM) from the observation of the thinnest parts of TEM samples. In this work, it is shown that faint contrasts of dissociated screw dislocations running parallel to the surfaces of a silicon TEM sample reveal free surface relaxation. The contrast features are fully explained from an approach involving an N‐beam theory of the electron diffraction and an appropriate elastic field. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Conditionally replicative adenoviral vectors for malignant glioma
Authors: Sonabend Adam M. , Ulasov Ilya V. , Lesniak Maciej S.
Published: January 2006

High‐grade gliomas constitute an important challenge to modern medicine, and although great effort has been made to prolong patient survival, the prognosis for this disease remains poor. Due to recent discoveries in the molecular basis of gliomas, gene therapy is becoming a promising alternative. In this review, we discuss the use of conditionally replicative adenoviral vectors (CRAd) and their applications in neuro‐oncology. Such vectors, when rendered conditionally replicative via transductional and transcriptional modifications, offer great promise for patients with malignant brain tumours. We review data from preclinical and clinical studies utilising such vectors and discuss the limitations and future perspectives of CRAd oncolytic therapy for malignant glioma. Copyright © 2006 John Wiley & Sons, Ltd.
Dynamic Rheology of Rice Starch‐Galactomannan Mixtures in the Aging Process
Authors: Kim Chion , Lee Sam‐Pin , Yoo Byoungseung
Published: January 2006

The effect of galactomananns (guar gum and locust bean gum) at different concentrations (0, 0.2, 0.4, 0.6 and 0.8%, w/w) on the dynamic rheological properties of aqueous rice starch dispersions (5%, w/w) was investigated by small‐deformation oscillatory measurements during aging. Magnitudes of storage (G′) and loss (G′′) moduli measured at 4°C before aging increased with the increase in gum concentration in the range of 0.2–0.8%. G′ and G′′ values of rice starch‐locust bean gum (LBG) mixtures, in general, were higher than those of rice starch‐guar gum mixtures. G′ values of rice starch‐guar gum mixtures as a function of aging time (10 h) at 4°C increased rapidly at initial stage and then reached a plateau region at long aging times. However, G′ values of rice starch‐LBG mixtures increased steadily without showing a plateau region. Increasing the guar gum concentration resulted in an increase in plateau values. The rate constant (K) for structure development during aging was described by first‐order kinetics. K values in rice starch‐guar gum mixtures increased with the increase in guar gum concentration. G′ values of rice starch‐galactomannan mixtures after aging were greater than those before aging.
Separation and Characterisation of Starch‐rich Fractions from Wild‐type and Mutant Pea Seeds
Authors: Al‐Abbas Sabah , Bogracheva Tatiana Y. , Topliff Ian O. , Crosley Iain , Hedley Cliff L.
Published: January 2006

Methods for milling and separation of flour from seeds of a normal (wild‐type) and two mutant (lam and r) types of pea (Pisum sativum L.) into starch‐rich and protein‐rich fractions are described. The methods entail using combinations of mills (100AFG, 50ZPS and 100UPZ) together with an air‐classification system based on a 50ATP air‐classifier, all run under a range of conditions to optimise the separation. The efficiency of separation was assessed as well as the economic advantages of the different systems. The best route for separation and fractionation was 2×100UPZ + 100AFG + 50ATP, while the most economic system that also gave good separation and fractionation was 2×100UPZ + 50ZPS + 50ATP, which had an energy consumption of 226 kWh/t. A novel method for determining the starch content within the high and low starch fractions is described. The method is based on a comparison between the gelatinisation enthalpy of starch in starch‐rich and in protein‐rich fractions with that for pure starch produced from the same flour, using differential scanning calorimetry. Qualitative assessments of the starch contents of the fractions were also made using microscopy and particle size distribution analysis. It is suggested that the starch‐rich fractions could be used as a relatively cheap raw material for non‐food applications.
Effect of Potato Starch Properties on Instant Noodle Quality in Wheat Flour and Potato Starch Blends
Authors: Noda Takahiro , Tsuda Shogo , Mori Motoyuki , Takigawa Shigenobu , Matsuura‐Endo Chie , Kim Sun‐Ju , Hashimoto Naoto , Yamauchi Hiroaki
Published: January 2006

The properties of potato starch and their effect on the quality of Chinese‐style alkaline instant noodles made from wheat flour and potato starch blends were investigated. Starches were extracted from nine potato cultivars, and the phosphorus content of these starches was analyzed together with the median granule size and pasting and gelatinization properties. Instant noodles were manufactured using mixtures of wheat flour and these potato starches. A Rheoner instrument was used to evaluate three textural parameters, namely, the breaking force (BF), breaking energy (BE), and ratio of the breaking force to the breaking deformation (BF/BD), of instant noodles cooked by immersing into boiling water for 3 and 7 min. The phosphorus content, peak viscosity, and breakdown were significantly and positively correlated with the BF of the noodles cooked for 3 min and did not significantly correlate with that of those cooked for 7 min. Other quality parameters of potato starch did not affect the BF significantly. Other textural parameters of instant noodle quality, such as the BE and BF/BD, did not significantly correlate with any of the quality parameters of potato starch. The findings obtained with the use of wheat flour and potato starch blends suggest that phosphate, which is thought to enhance starch viscosity of potato starch, is important for making instant noodles with favorable texture in hardness.
INFLUENCE OF TIME OF APPLICATION ON THE PERFORMANCE OF GLIRICIDIA PRUNINGS AS A SOURCE OF N FOR MAIZE
Authors: MAKUMBA WILKSON , JANSSEN BERT , OENEMA OENE , AKINNIFESI FESTUS K.
Published: January 2006

Asynchrony between nitrogen (N) released by organic materials and N demand by the crop leads to low N use efficiency. Optimizing the time of application could increase the N recovery. A field experiment was designed to determine the effects of time of application of Gliricidia sepium prunings and of the addition of small doses of inorganic N fertilizer on N recovery and yield of maize. Six split applications of gliricidia prunings (in October, December and February) were compared. The prunings were incorporated into the soil while fresh. The application in October was done four weeks before planting the maize. Higher N uptake and maize yields were obtained when gliricidia prunings were applied in October than when applied in December and February. The corresponding substitution values were 0.66, 0.32 and 0.20. Split applications of prunings prolonged mineral N availability in the soil until March but did not increase N uptake and maize grain yield compared to a sole application in October. Combinations of gliricidia prunings and inorganic fertilizer increased N uptake and maize yield over prunings alone but the effect was only additive. We concluded that application of gliricidia prunings in October was more efficient than application in December and February.
Passionate Comparison: The Intensification of Affect in Interreligious Reading of Hindu and Christian Texts
Authors: Clooney Francis X.
Published: January 2006

How do we learn from religious traditions other than our own? How are we to assess what happens when that learning leads to affirmation and empathy, and thereafter affects how one lives one's life? We can wonder whether there is coherence in what we learn, what we think, how we feel, and how we choose to act. Optimism is not necessarily justified since it may be that due to the strictures of logic and religious commitment, religious reasoning and affective religious engagement diverge and even work at cross purposes. What is obviously and powerfully felt may not translate into explanations that observers, including theologians and scholars of religion, can understand or affirm. Conversely, the emotionally engaged practitioner who learns, feels, and acts in accord with what is learned across religious boundaries may not know what to say about this engagement, and often may not have mastered the appropriate technical language by which to explain and justify complex and extraordinary emotional engagements.
The Virgin Mary in the Ministry of Jesus and the Early Church according to the Earliest
Life of the Virgin
Authors: Shoemaker Stephen J.
Published: January 2006

In 1986, Michel van Esbroeck published a remarkable new Life of the Virgin that not only is among the most profound and eloquent Mariological writings of early Byzantium but also presents a useful compendium of early apocryphal traditions about Mary. Some of the Life's episodes are already well known from their original sources, such as the Protevangelium of James and the early dormition apocrypha, but many other extrabiblical traditions appearing in this Life of the Virgin are not otherwise attested in early Christian literature. This is true especially of the section that overlaps with the gospels, where the Life expands the canonical narratives in ways unprecedented (to my knowledge) in Christian apocryphal literature. By writing Mary into the story at key points and augmenting several of her more minor appearances, the Life portrays Mary as a central figure in her son's ministry and also as a leader of the nascent church. The result is a veritable “Gospel of Mary” in the section of the Life that emphasizes Mary's essential contributions to her son's earthly mission and her leadership of the apostles in the early Christian community: the Life gives a brief account of the same events recorded in the canonical gospels, but with the Virgin Mary brought to the fore at nearly every instance. The origins of these traditions are not entirely clear, and while they may be the work of the Life's author, it is equally possible that they reflect now lost apocryphal traditions about Mary that once circulated in late antiquity. In any case, the attention that this earliest Life of the Virgin lavishes on the activities of Mary and other women as important leaders in the formation of Christianity is rather striking and quite exceptional among the literature of Christian late antiquity. In its emphasis on the roles played by these women it represents a surprising ancient predecessor to much of the recent work in New Testament scholarship to recover the importance of women in the early Christian movement.
Detection and identification of Lactobacillus delbrueckii subsp. lactis bacteriophages by PCR
Authors: Zago Miriam , De Lorentiis Angela , Carminati Domenico , Comaschi Lucia , Giraffa Giorgio
Published: January 2006

A sensitive PCR method amplifying an internal fragment of the major tail protein gene was developed to detect Lactobacillus delbrueckii subsp. lactis lytic bacteriophages in undefined, thermophilic whey starters used in Italy for production of Grana and Provolone cheeses. PCR was applied to several lytic Lb. delbrueckii subsp. lactis bacteriophages, which were highly diverse according to restriction analysis and phage host range. PCR detected the presence of phages in two out of 11 cultures, when applied to whey starters for Grana Padano cheese sampled from different cheese plants. The presence of actively growing phages in infected cultures was confirmed by traditional test. The PCR method proved to be useful to screen for the presence of Lb. delbrueckii subsp. lactis phages in thermophilic whey starters.
The possibility of alternative microbial life on Earth
Authors: Cleland Carol E. , Copley Shelley D.
Published: January 2006

Despite its amazing morphological diversity, life as we know it on Earth today is remarkably similar in its basic molecular architecture and biochemistry. The assumption that all life on Earth today shares these molecular and biochemical features is part of the paradigm of modern biology. This paper examines the possibility that this assumption is false, more specifically, that the contemporary Earth contains as yet unrecognized alternative forms of microbial life. The possibility that more than one form of life arose on Earth is consistent with our current understanding of conditions on the early Earth and the biochemical and molecular possibilities for life. Arguments that microbial descendents of an alternative origin of life could not co-exist with familiar life are belied by what we know of the complexity and diversity of microbial communities. Furthermore, the tools that are currently used to explore the microbial world – microscopy (with the aid of techniques such as DAPI staining and fluorescence in situ hybridization), cultivation and PCR amplification of rRNA genes – could not detect such organisms if they existed. Thus, the fact that we have not discovered any alternative life forms cannot be taken as evidence that they do not exist.
On the applicability of the principle of the quantity-to-quality transition to chemical evolution that led to life
Authors: Kolb Vera M.
Published: January 2006

We review and re-examine the arguments for the proposal that life emerged by a quantity-to-quality transition of abiotic matter. This idea was originally proposed by the dialectical materialists, who are the proponents of the materialistic approach to Hegel's laws of dialectics. We find that one of the universal features of the quantity-to-quality transitions is the change in the organization of the system, which brings about novelty. We suggest that the principle of the quantity-to-quality transition may be a part of the algorithm of life, which is not Earth-centric.
SINGAPORE, HONG KONG AND THE END OF EMPIRE
Authors: Kratoska Paul H.
Published: January 2006

As major Asian trading centres and former British colonies, Singapore and Hong Kong inevitably have parallel histories. Although their destinies diverged in the latter part of the twentieth century, comparisons between the two places are useful in developing an understanding of the historical circumstances of each city, and also in developing regional perspectives. The burden of the present article lies in three arguments. First, while the Japanese occupation is often seen as a climactic event in Asian history that destroyed the colonial world and set in motion the transition to independence, the economic policies that defined the post-war era were initiated by colonial regimes during the 1930s and continued by nationalist governments after 1945. Second, the political trajectories followed by Singapore and Hong Kong in the first post-war decades were largely determined by unanticipated developments relating to the cold war, and did not follow logically from the situation that existed in the 1930s, or even when the war ended in August 1945. Third, while both places were seen as colonial relics in post-war Southeast Asia and had to contend with nationalist policies that were incompatible with their social make-up and business practices, efforts to assimilate them within national states were unsuccessful, and they continued to flourish as global city states.
HISTORICAL MEMORIES OF A CHINESE ADVENTURER IN A TAY CHRONICLE; USURPATION OF THE THRONE OF A TAY POLITY IN YUNNAN, 1573–1584
Authors: Daniels Christian
Published: January 2006

By analysing a Tay chronicle and Chinese sources about a case of usurpation in the Tay (Shan) polity of Mäng: Wan: located in southwest Yunnan on the border with Burma (Myanmar) in 1573, this article offers an alternative approach to the use of chronicles as sources for the history of the Tay Cultural Area. It argues that Tay chronicles are media for the creation and transmission of historical memories, and that they can be utilized to redress the excessive subjectivity of Chinese sources precisely because they show how the Tay interpreted events. Analyses of these interpretations in turn reveal the principal concepts underlying Tay political and social organization, thereby allowing historians to establish benchmarks for ascertaining the changes that took place in Tay polities. This study emphasizes that the memory of the usurpation was generated by the realities of Mäng: Wan:'s power relations with China and Burma, and demonstrates that apart from elucidating the role of royal succession, these memories also throw light on some of the larger recurring themes in the history of Tay relations with China, such as the role of Han Chinese migrants in polity building and administration and land alienation by contractual transactions.
ASIAN PERSPECTIVES. ASIAN STUDIES IN “CRISIS”: IS CULTURAL STUDIES THE ANSWER?
Authors: Clark Juliet
Published: January 2006

This article explores some of the benefits and limitations of Cultural Studies in Asian studies with particular reference to the expression of Asian-Australian identity in diaspora. It has been suggested that the influence of Cultural Studies – a discipline that is viewed as more globally relevant – may be an answer to the Asian studies “crisis”. In relation to the Cultural Studies approach to Asian-Australian identity, I argue that the discourse and rhetoric of Cultural Studies is highly beneficial in breaking down stereotypes and rebuilding the national narrative of identity. However, as a methodology it is not without limitations.
Chemical model for mid‐summer lidar observations of mesospheric potassium over the Arecibo Observatory
Authors: Delgado Rubén , Weiner Brad R. , Friedman Jonathan S.
Published: January 2006

To understand the mid‐summer nocturnal mesospheric K layer over the Arecibo Observatory (18.35°N, 66.75°W) a one dimensional model has been developed. Focusing on nights with no sporadic layer activity, we identify possible molecular reservoirs and sinks in the K layer using ab initio calculations to estimate the thermochemistry. Reactions KN2+ + O, KN2+ + CO2, and KHCO3 + H play primary roles in the chemistry of ionic and neutral potassium in the mesospheric cycle. The predominant potassium species is KHCO3 as a result of the influence of odd oxygen/hydrogen chemistry. The study of the metal layer contributes to a better understanding of chemical and dynamic changes that affect atmospheric composition.
On the summer poleward coastal current off SW México
Authors: Lavín M. F. , Beier Emilio , Gómez‐Valdés José , Godínez Víctor M. , García J.
Published: January 2006

For the first time on the basis of direct observations (June 2003 and June 2005), the characteristics of the summer‐time coastal poleward current off SW Mexico are reported. Only the surface evidence of this coastal current has previously been described, from ship drift compilations. In June 2003 the current was 90–180 km wide, 400 m deep, with speed ∼0.3 ms−1 and transport ∼4 Sv (1 Sv = 106 m3 s−1). In June 2005, its width was ∼90 km, it was 250–300 m deep, with mean speed ∼0.15 m s−1 and transport ∼2.5 Sv. California Current water (CCW) and equatorward flow were found further offshore. Mesoscale eddies significantly affected the coastal current, and transported CCW into the coastal zone.
New observations of artificial aurora associated with TMA releases
Authors: Gelinas L. J. , Siefring C. L. , Bernhardt P. A. , Larsen M. F. , Kelley M. C. , Hecht J.
Published: January 2006

An artificial aurora was generated during a trimethyl aluminum (TMA) release from the October 2000 TOMEX rocket launch. Cameras in several locations filmed the optical emissions, believed to be associated with small amounts of kerosene added to the TMA liquid. The geometry of the launch trajectory with respect to the magnetic field and camera viewing angles has provided new insight on the source of the emissions. Surprisingly, the aurora appears to be associated with the vertical footprint of the rocket, rather than the magnetic footprint of the rocket, as previously assumed. The new observations favor a generation mechanism involving large particles >1 μm falling to 90 km altitude.
Rip spacing and persistence on an embayed beach
Authors: Holman R. A. , Symonds G. , Thornton E. B. , Ranasinghe R.
Published: January 2006

Four years of daily time exposure images from an embayed beach were examined to study the spacing, persistence, and location preferences of rips in a natural rip channel system. A total of 5271 rip channels was observed on 782 days. Occurrence statistics showed no evidence of the preferred location pattern associated with standing edge waves trapped in an embayed beach. The histogram of rip spacing, the primary diagnostic observable for most models, was well modeled by a lognormal distribution (mean spacing of 178 m). However, spacings were highly longshore variable (time mean of the standard deviation/longshore mean of rip spacing was 39%), so they are of questionable merit as a diagnostic variable. Storm‐driven resets to the longshore uniform condition required by most models occurred only four times per year on average, making rip generation models relevant to only a small fraction of the system behavior. Rip spacings after the 15 observed reset events were uncorrelated with bar crest distance. The lifetime of the 324 individual rip channel trajectories averaged 45.6 days. Rips were equally mobile in both longshore directions, but the coefficient of variation of rip migration rates was large, even for high migration rates. The mean migration rate was well correlated to a proxy for the longshore current (R2 of 0.78). Thus there is no significant evidence that the formation, spacing, and migration of rip channels on this beach can be explained by currently existing simple models. Moreover, the alongshore uniform initial conditions assumed by these models are rare on Palm Beach, making the models generally inapplicable.
Chemical data assimilation of Transport and Chemical Evolution over the Pacific (TRACE‐P) aircraft measurements
Authors: Chai Tianfeng , Carmichael Gregory R. , Sandu Adrian , Tang Youhua , Daescu Dacian N.
Published: January 2006

In this paper, the four‐dimensional variational (4D‐Var) technique is applied to assimilate aircraft measurements during the Transport and Chemical Evolution over the Pacific (TRACE‐P) field experiment into a chemical transport model, Sulfur Transport Eulerian Model, version 2K1 (STEM‐2K1). Whether data assimilation would produce better analyzed fields is examined. It is found that assimilating ozone observations from one of two independent flights improves model prediction of the other flight ozone measurements, which are withheld as validation data. The adjusted initial fields after only assimilating the total reactive nitrogen (NOy) observations lead to better predictions of NO, NO2, and PAN, based on their agreement with the withheld measurements. One experiment simultaneously assimilating the observations of O3, NO, NO2, HNO3, PAN, and RNO3 demonstrates that the model is able to match those measurements well by changing the initial fields. In addition, the model predictions of NOy improve significantly after assimilating the aforementioned multiple observation species, which are independent of the withheld NOy measurements. In the paper, we also show that the key species whose initial mixing ratios would significantly affect the agreement between model and measurements can be identified using adjoint sensitivity analysis. Such information can be used to reduce the number of control variables in the 4D‐Var data assimilation. To speed up the optimization process in the 4D‐Var, we enforce the concentration upper bounds through the limited memory–Broyden‐Fletcher‐Goldfarb‐Shanno‐B (L‐BFGS‐B) algorithm, and this proves to be effective.
Chronology reconstruction for the disturbed bottom section of the GISP2 and the GRIP ice cores: Implications for Termination II in Greenland
Authors: Suwa Makoto , von Fischer Joseph C. , Bender Michael L. , Landais Amaelle , Brook Edward J.
Published: January 2006

We have reconstructed chronology for the disturbed bottom parts of the GRIP and GISP2 ice cores using the combined paleoatmospheric records of CH4 concentration and δ18Oatm in the trapped gases. Our reconstructed ages for basal ice samples are based on comparison of published measurements of CH4 and δ18Oatm from the disturbed section of the GRIP and GISP2 cores with the same properties in the Vostok ice core. NGRIP δ18Oice values are also used to constrain the chronology during the end of marine isotope stage 5e. For each sample, we assign an age that represents the unique or most probable time of gas trapping, given its gas composition. Of 157 samples with CH4 and δ18Oatm data, 10 give unique ages. Twenty‐five newly measured values of the triple isotope composition of O2 from the disturbed section of the GISP2 core add a third time‐dependent gas property that agrees with our reconstruction. Our reconstruction supports earlier conclusions of Landais et al. (2003) that the disturbed section primarily includes ice from the last interglacial (MIS 5e) and the penultimate glacial period (MIS 6). The oldest ice in the basal layer of GISP2 and GRIP has an age ≥237 ka. The climate history we derive suggests that the last interglacial at Summit, Greenland, around 127 ka was slightly warmer than the current interglacial period. Reduction of various ion concentrations in ice and thickening of the ice sheet during Termination II was similar to that in Termination I.
Mapping compositional diversity on the surface of Mars: The Spectral Variance Index
Authors: Martínez‐Alonso Sara , Mellon Michael T. , Kindel Bruce C. , Jakosky Bruce M.
Published: January 2006

The advent of high spatial resolution instruments onboard orbiting Mars missions entails the need for identification of critical regions to be analyzed in further detail. We present the Spectral Variance Index (SVI), a method to detect regions of large surface materials diversity compared to the average of the planet. Such diversity may be indicative of significant active and past geological processes, such as hydrothermal activity, chemical and mechanical sedimentation, pyroclastic volcanism, erosion unveiling layering of diverse composition, and weathering, among others. The SVI was derived from statistical analysis of the Mars Global Surveyor Thermal Emission Spectrometer spectral data set for 5 × 5 degree cells covering the entire planet; global SVI maps depicting surface materials diversity were produced. Regions of elevated SVI occur clustered in low‐albedo, high‐thermal inertia regions, indicative of rock‐dominated surfaces. The surface geology of two regions of anomalously high SVI (Nili Fossae and Mare Tyrrhenum), and one region of low SVI (Amazonis Planitia), was investigated utilizing spectroscopic, thermophysical, and morphological data. The following data‐derived spectral end‐members were identified in all three regions: atmospheric water‐ice, surface dust (both in close spatial relationship), and instrument noise. The high SVI regions show also signatures characteristic of surfaces type 1 and 2, forsterite (Nili), phyllosilicates and/or high‐Si glass (Nili), and another end‐member most consistent with fayalite (or, alternatively, high‐Ca pyroxene) in volcanic materials (Tyrrhenum). The SVI method effectively identifies regions, both previously known and new ones, of surface material diversity on Mars; spectroscopic data of higher spatial resolution will improve our understanding of their compositional diversity.
The antiarrhythmic peptide rotigaptide (ZP123) increases gap junction intercellular communication in cardiac myocytes and HeLa cells expressing connexin 43
Authors: Clarke Thomas C , Thomas Dafydd , Petersen Jørgen S , Evans W Howard , Martin Patricia E M
Published: January 2006

We investigated the effects of rotigaptide (ZP123), a stable hexapeptide with antiarrhythmic properties, on gap junction mediated intercellular communication in contracting rat neonatal cardiac myocytes, HL‐1 cells derived from cardiac atrium and in HeLa cells transfected with cDNA encoding Cx43‐GFP, Cx32‐GFP, Cx26‐GFP, wild‐type Cx43 or wild‐type Cx26.

Intercellular communication was monitored before and after treatment with rotigaptide following microinjection of small fluorescent dyes (MW<1 kDa). The communication‐modifying effect of rotigaptide was confined to cells expressing Cx43 since the peptide had no effect on dye transfer in HeLa cells expressing Cx32‐GFP, Cx26‐GFP or wild‐type Cx26. In contrast, HeLa cells expressing Cx43‐GFP exposed to 50 nM rotigaptide for 5 h showed a 40% increase in gap junction mediated communication.

Rotigaptide (50 nM) increased intercellular dye transfer in myocytes and atrial HL‐1 cells, where Cx43 is the dominant connexin. However, it caused no change in cell beating rates of cardiac myocytes.

Western blot analysis showed that rotigaptide did not modify the overall level of Cx43 expression and changes in the phosphorylation status of the protein were not observed.

We conclude that the effects of rotigaptide were confined to cells expressing Cx43.

British Journal of Pharmacology (2006) 147, 486–495. doi:10.1038/sj.bjp.0706631
Effects of haloperidol and clozapine on sensorimotor gating deficits induced by 5‐hydroxytryptamine depletion in the brain
Authors: Kusljic Snezana , Brosda Jan , Van Den Buuse Maarten
Published: January 2006

Evidence is increasing for a role of brain 5‐hydroxytryptamine (5‐HT) systems in schizophrenia. We previously showed that brain 5‐HT depletion causes disruption of prepulse inhibition, a measure of sensorimotor gating that is deficient in schizophrenia. Antipsychotic treatment has been reported to reverse these deficits in patients with schizophrenia. The present study was designed to investigate the ability of antipsychotic drugs to reverse prepulse inhibition deficits caused by lesions of the brain 5‐HT system in rats.

In male Sprague–Dawley rats, selected parts of the brain 5‐HT systems were lesioned by micro‐injection of the 5‐HT neurotoxin 5,7‐dihydroxytryptamine into the dorsal raphe nucleus (DRN) or median raphe nucleus (MRN). The effects of antipsychotic drugs on lesion‐induced changes in prepulse inhibition were examined 2 weeks after the surgery.

There was significant disruption of prepulse inhibition in the MRN‐lesioned group compared to sham‐operated controls. This deficiency in prepulse inhibition was restored by clozapine (1 and 5 mg kg−1) treatment, and by treatment with a relatively high dose of haloperidol (0.25 mg kg−1). There was no significant effect of the DRN lesions on prepulse inhibition compared with sham‐operated controls.

These results indicate that 5‐HT depletion in MRN‐innervated brain structures leads to disruption of prepulse inhibition. Treatment with both antipsychotic drugs, haloperidol and clozapine, significantly increased prepulse inhibition in these animals back to the level seen in sham‐operated controls. The present findings highlight the importance of the 5‐HT systems in cognitive models of schizophrenia.

British Journal of Pharmacology (2006) 147, 800–807. doi:10.1038/sj.bjp.0706641
A role for voltage‐gated, but not Ca2+‐activated, K+channels in regulating spontaneous contractile activity in myometrium from virgin and pregnant rats
Authors: Aaronson Philip Irving , Sarwar Uzma , Gin Stephanie , Rockenbauch Uli , Connolly Michelle , Tillet Alexandra , Watson Sarah , Liu Bing , Tribe Rachel Marie
Published: January 2006

The roles of voltage‐gated (KV) and large conductance Ca2+‐activated K+(BKCa) channels in regulating basal contractility in myometrial smooth muscle are unresolved. The aim of this study was to determine the effects of inhibition of these channels on spontaneous rhythmic contraction in myometrial strips from four groups of rats: nonpregnant and during early (day 7), mid‐ (day 14), and late (day 21) pregnancy.

BKCachannels were inhibited using iberiotoxin (1–100 nM), paxilline (1–10 μM) or penitrem A (1–500, or 3000 nM);KVchannels were inhibited using tetraethylammonium (TEA; 1–10 mM) and/or 4‐aminopyridine (4‐AP; 1–5 mM). Contractility was assessed as mean integral tension (MIT). Time/vehicle controls were also performed.

None of the selective BKCachannel inhibitors significantly affected contractility in myometrial strips from either nonpregnant or pregnant animals.

4‐AP caused concentration‐dependent increases in MIT in myometrium in all four groups. TEA (5 and 10 mM) significantly increased MIT in myometrium from nonpregnant, and mid‐ and late pregnant rats, but not in myometrium from early pregnant rats. TEA and 4‐AP still caused an increase in MIT following treatment with 3000 nMpenitrem A or a combination of propranolol, phentolamine, atropine (all 1 μM) and capsaicin (10 μM) in myometrial strips from nonpregnant rats.

These results indicate that whereas BKCachannels play little or no part in controlling basal rhythmicity in rat myometrium,KVchannels appear to play a crucial role in this regard, especially during mid‐ and late pregnancy.

British Journal of Pharmacology(2006)147, 815–824. doi:10.1038/sj.bjp.0706644
Angiotensin II acutely decreases myocardial stiffness: a novel AT1, PKC and Na+/H+exchanger‐mediated effect
Authors: Leite‐Moreira Adelino F , Castro‐Chaves Paulo , Pimentel‐Nunes Pedro , Lima‐Carneiro Alexandre , Guerra Miguel S , Soares João Bruno , Ferreira‐Martins João
Published: January 2006

Acute effects of angiotensin II (AngII) on diastolic properties of the myocardium were investigated.

Increasing concentrations of AngII (10−9to 10−5 M) were added to rabbit papillary muscles in the absence (n=11) or presence of: (i) AT1 receptor antagonists, losartan (10−6 M;n=7) or ZD‐7155 (10−7 M;n=8); (ii) ZD‐7155 (10−7 M) plus AT2 receptor antagonist PD‐123,319 (2 × 10−6 M;n=6); (iii) PKC inhibitor, chelerythrine (10−5 M;n=8); or (iv) Na+/H+exchanger (NHE) inhibitor, 5‐(N‐methyl‐N‐isobutyl)‐amiloride (10−6 M;n=10). Passive length–tension relations were constructed before and after a single concentration of AngII (10−5 M,n=6). Effects of AngII infusion (10 μg kg−1 min−1) were evaluated inin siturabbit hearts.

AngII concentration dependently increased inotropy and resting muscle length (RL). At 10−5 M, active tension increased 43.3±6.25% and RL 1.96±0.4%. Correcting RL to its initial value resulted in a 46±4% decrease of resting tension, indicating decreased muscle stiffness, as confirmed by the right and downward shift of the passive length–tension relation promoted by AngII. In the intact heart, at matched systolic pressures of 112 mmHg, AngII decreased end‐diastolic pressures from 10.3±0.3 to 5.9±0.5 mmHg, and minimal diastolic pressures from 8.4±0.5 to 4.6±0.6 mmHg.

AT1 blockade inhibited AngII effects on myocardial inotropy and stiffness, while PKC or NHE inhibition only significantly attenuated its effects on resting length and tension.

In conclusion, AngII decreases myocardial stiffness, an effect that requires AT1 receptor activation and is mediated by PKC and NHE. This represents a novel mechanism of acute neurohumoral modulation of diastolic function, suggesting that AngII is a powerful regulator of cardiac filling.

British Journal of Pharmacology(2006)147, 690–697. doi:10.1038/sj.bjp.0706659
Differential activation of G‐proteins byμ‐opioid receptor agonists
Authors: Saidak Zuzana , Blake‐Palmer Katherine , Hay Debbie L , Northup John K , Glass Michelle
Published: January 2006

We investigated the ability of the activatedμ‐opioid receptor (MOR) to differentiate between myristoylated Gαi1and GαoAtype G proteins, and the maximal activity of a range of synthetic and endogenous agonists to activate each G protein.

Membranes from HEK293 cells stably expressing transfected MOR were chaotrope extracted to denature endogenous G‐proteins and reconstituted with specific purified G‐proteins. The G subunits were generated in bacteria and were demonstrated to be recognised equivalently to bovine brain purified G protein by CB1cannabinoid receptors. The ability of agonists to catalyse the MOR‐dependent GDP/[35S]GTPS exchange was then compared for Gαi1and GαoA.

Activation of MOR by DAMGO produced a high‐affinity saturable interaction for GαoA(Km=20±1 nM) but a low‐affinity interaction with Gαi1(Km=116±12 nM). DAMGO, met‐enkephalin and leucine‐enkephalin displayed maximal G activation among the agonists evaluated. Endomorphins 1 and 2, methadone andβ‐endorphin activated both G to more than 75% of the maximal response, whereas fentanyl partially activated both G‐proteins.

Buprenorphine and morphine demonstrated a statistically significant difference between the maximal activities between Gαi1and GαoA. Interestingly, DAMGO, morphine, endomorphins 1 and 2, displayed significant differences in the potencies for the activation of the two G. Differences in maximal activity and potency, for Gαi1versusGαoA, are both indicative of agonist selective activation of G‐proteins in response to MOR activation.

These findings may provide a starting point for the design of drugs that demonstrate greater selectivity between these two G‐proteins and therefore produce a more limited range of effects.

British Journal of Pharmacology(2006)147, 671–680. doi:10.1038/sj.bjp.0706661
The basic secretagogue compound 48/80 activates G proteins indirectlyviastimulation of phospholipase D–lysophosphatidic acid receptor axis and 5‐HT1Areceptors in rat brain sections
Authors: Palomäki Ville A B , Laitinen Jarmo T
Published: January 2006

The basic secretagogues, such as compound 48/80 (c48/80) and mastoparans, are widely used histamine‐releasing agents and their mechanism of action is commonly attributed to a direct, receptor‐bypassing property to activate the Gi/oclass of G proteins.

We tested here whether c48/80 could directly stimulate [35S]guanosine‐5′‐[γ‐thio]triphosphate ([35S]GTPγS) binding to rat brain sections in an attempt to visualize the entire signaling pool of Gi/oin its native neuroanatomical context.

Instead of direct Gi/oactivation, c48/80 (100 μg ml−1) from various suppliers stimulated brain phospholipase D (PLD) activity, leading to the generation of endogenous phospholipids capable of activating brain white matter‐enriched, Gi/o‐coupled lysophosphatidic acid (LPA) receptors. This response was sensitive to 1‐butanol and was potently reversed by the LPA1/LPA3receptor‐selective antagonist Ki16425 (IC5059±13 nM, mean±s.e.m.), and showed age‐dependent decline, closely reflecting known developmental regulation of the PLD–LPA1receptor axis in the CNS.

In addition, c48/80 was found to modestly activate hippocampal 5‐HT1Areceptors in a pH‐dependent and antagonist‐sensitive manner.

Consistent with the lack of direct Gi/o‐activating properties in brain sections, c48/80 showed no activity in classical membrane [35S]GTPγS binding assays. Instead, c48/80 from one particular manufacturer elicited non‐specific effect in these assays, therefore challenging the previous interpretations regarding the compound's ability to activate G proteins directly.

We conclude that c48/80 is not a receptor‐bypassing general G protein activator but rather activates PLD, leading to generation of endogenous LPA receptor‐activating phospholipids. This property may also contribute to the compound's ability to release histamine from mast cells.

British Journal of Pharmacology(2006)147, 596–606. doi:10.1038/sj.bjp.0706671
Accurate ab initio potential for the Na+⋯I• complex
Authors: Timerghazin Qadir K. , Koch Denise M. , Peslherbe Gilles H.
Published: January 2006

High-level ab initio calculations employing the multireference configuration interaction and coupled clusters methods with a correlation-consistent sequence of basis sets have been used to obtain accurate potential energy curves for the complex of the sodium cation with the iodine atom. Potential curves for the first two electronic Λ-S states have very different characters: the potential for the Π2 state has a well depth of ∼10kcal∕mol, while the Σ2 state is essentially unbound. This difference is rationalized in terms of the anisotropic interaction of the quadrupole moment of the iodine atom with the sodium cation, which is stabilizing in the case of the Π2 state and destabilizing in the case of the Σ2 state. The effects of spin-orbit coupling have been accounted for with both ab initio and semiempirical approaches, which have been found to give practically the same results. Inclusion of spin-orbit interactions does not affect the X(Ω=3∕2) ground state, which retains its Π2 character, but it results in two Ω=1∕2 spin-orbit states, with mixed Σ2 and Π2 characters and binding energies roughly half of that of the ground spin-orbit state. Complete basis set (CBS) extrapolations of potential curves, binding energies, and equilibrium geometries were also performed, and used to calculate a number of rovibronic parameters for the Na+⋯I• complex and to parameterize model potentials. The final CBS-extrapolated and zero-point vibrational energy-corrected binding energy is 10.2kcal∕mol. Applications of the present results for simulations of NaI photodissociation femtosecond spectroscopy are discussed.
Reconciling semiclassical and Bohmian mechanics. II. Scattering states for discontinuous potentials
Authors: Trahan Corey , Poirier Bill
Published: January 2006

In a previous paper [B. Poirier, J. Chem. Phys. 121, 4501 (2004)] a unique bipolar decomposition, Ψ=Ψ1+Ψ2, was presented for stationary bound states Ψ of the one-dimensional Schrödinger equation, such that the components Ψ1 and Ψ2 approach their semiclassical WKB analogs in the large action limit. Moreover, by applying the Madelung-Bohm ansatz to the components rather than to Ψ itself, the resultant bipolar Bohmian mechanical formulation satisfies the correspondence principle. As a result, the bipolar quantum trajectories are classical-like and well behaved, even when Ψ has many nodes or is wildly oscillatory. In this paper, the previous decomposition scheme is modified in order to achieve the same desirable properties for stationary scattering states. Discontinuous potential systems are considered (hard wall, step potential, and square barrier/well), for which the bipolar quantum potential is found to be zero everywhere, except at the discontinuities. This approach leads to an exact numerical method for computing stationary scattering states of any desired boundary conditions, and reflection and transmission probabilities. The continuous potential case will be considered in a companion paper [C. Trahan and B. Poirier, J. Chem. Phys. 124, 034116 (2006), following paper].
The Euclidean scalar Green function in the five-dimensional Kaluza-Klein magnetic monopole space-time
Authors: Bezerra de Mello E. R.
Published: January 2006

In this paper we present, in a integral form, the Euclidean Green function associated with a massless scalar field in the five-dimensional Kaluza-Klein magnetic monopole superposed to a global monopole, admitting a nontrivial coupling between the field with the geometry. This Green function is expressed as the sum of two contributions: the first one related with uncharged component of the field, is similar to the Green function associated with a scalar field in a four-dimensional global monopole space-time. The second contains the information of all the other components. Using this Green function it is possible to study the vacuum polarization effects on this space-time. Explicitly we calculate the renormalized vacuum expectation value ⟨Φ*(x)Φ(x)⟩Ren, which by its turn is also expressed as the sum of two contributions.
Auger effect in the generalized kinetic theory of electrons and holes
Authors: Rossani A. , Spiga G.
Published: January 2006

In this paper we propose a model for a proper kinetic description of the Auger effect as a generation/recombination mechanism for electrons and holes in a bipolar device. Boltzmann-type equations for the two-species population in a phonon background are presented, and equilibria and their stability are investigated. Particles and quasiparticles are allowed to obey generalized statistics, in order to possibly include nonstandard or nonextensive effects. The macroscopic recombination/generation rate is recovered as hydrodynamic limit.