bluuebunny/crossref_metadata_2025 huggingface dataset:
High School Social Climate and Antisocial Behavior: A 10 Year Longitudinal and Multilevel Study
Authors: LeBlanc Line , Swisher Raymond , Vitaro Frank , Tremblay Richard E.
Published: August 2008

A longitudinal and multilevel approach is used to examine the relationship between antisocial behavior during adolescence and high school social climate. The data are taken from a longitudinal study of 1,233 boys and girls who attended 217 public and private high schools. Students' disruptive behaviors were assessed yearly from 6 to 12 years of age. High school social climate was assessed by teachers, and students reported on their violent and nonviolent antisocial behavior while in high school. The multilevel analyses revealed (1) a large difference between the percentage of variance explained within schools (97%), compared with between schools (3%), and (2) teachers' reports of classroom behavior problems explain between‐school differences in student reported antisocial behavior, after controlling for students' family adversity and history of behavior problems during elementary school. The theoretical and practical implications of the study are examined and future directions for research are discussed.
A Longitudinal Study of Depressive Symptoms and Marijuana Use in a Sample of Inner‐City African Americans
Authors: Repetto Paula B. , Zimmerman Marc A. , Caldwell Cleopatra H.
Published: August 2008

The association between marijuana use and depressive symptoms was examined longitudinally in a sample of 622 African American youth, interviewed on six occasions, using hierarchical linear modeling (HLM). We considered whether depressive symptoms predicted changes in marijuana use and vice versa from high school through the transition into young adulthood. We also examined gender differences in these behaviors over time. The results indicated that depressive symptoms predicted later marijuana use only for males. Marijuana use did not predict later depressive symptoms for females or males. These findings are consistent with a unidirectional hypothesis indicating that marijuana use may play a role as mood regulator among young males, but not among females. Research findings also indicate that females with lower depressive symptoms use more marijuana than females who report high depressive symptoms. These findings did not change even after controlling for the effects of using other substances at previous stages, school achievement, and demographics factors. These results suggest that depressive symptoms may be an antecedent of marijuana use among African American males.
Identifying Monetary Policy Shocks via Changes in Volatility
Authors: LANNE MARKKU , LÜTKEPOHL HELMUT
Published: August 2008

A central issue of monetary policy analysis is the specification of monetary policy shocks. In a structural vector autoregressive setting there has been some controversy about which restrictions to use for identifying the shocks because standard theories do not provide enough information to fully identify monetary policy shocks. In fact, to compare different theories it would even be desirable to have over‐identifying restrictions that would make statistical tests of different theories possible. It is pointed out that some progress toward over‐identifying monetary policy shocks can be made by using specific data properties. In particular, it is shown that changes in the volatility of the shocks can be used for identification. Based on monthly U.S. data from 1965 to 1996 different theories are tested and it is found that associating monetary policy shocks with shocks to nonborrowed reserves leads to a particularly strong rejection of the model whereas assuming that the Fed accommodates demand shocks to total reserves cannot be rejected.
The Role of Interbank Markets in Monetary Policy: A Model with Rationing
Authors: FREIXAS XAVIER , JORGE JOSÉ
Published: August 2008

This paper analyzes the impact of asymmetric information in the interbank market and establishes its crucial role in the microfoundations of the monetary policy transmission mechanism. We show that interbank market imperfections induce an equilibrium with rationing in the credit market. This has two major implications: first, it reconciles the irresponsiveness of business investment to the user cost of capital with the large impact of monetary policy (magnitude effect), and second, it shows that banks' liquidity positions condition their reaction to monetary policy (Kashyap and Stein liquidity effect).
Geographic Diversification, Bank Holding Company Value, and Risk
Authors: DENG SAIYING (ESTHER) , ELYASIANI ELYAS
Published: August 2008

We assess the association between geographic diversification and bank holding company (BHC) value and risk, controlling for the distance between the headquarters and branches. The distance‐adjusted deposit dispersion index used as a measure of geographic diversification accounts for the number of locations where a BHC operates, the level of activity in each location, and the distance between a BHC and its branches. We find that geographic diversification is associated with BHC value enhancement and risk reduction, increased distance between a BHC and its branches is associated with firm value reduction and risk increase, and geographic diversification across more remote areas is associated with greater value enhancement but smaller risk reduction.
A Thin Film Approach to Engineering Functionality into Oxides
Authors: Schlom Darrell G. , Chen Long‐Qing , Pan Xiaoqing , Schmehl Andreas , Zurbuchen Mark A.
Published: August 2008

The broad spectrum of electronic and optical properties exhibited by oxides offers tremendous opportunities for microelectronic devices, especially when a combination of properties in a single device is desired. Here we describe the use of reactive molecular‐beam epitaxy and pulsed‐laser deposition to synthesize functional oxides, including ferroelectrics, ferromagnets, and materials that are both at the same time. Owing to the dependence of properties on direction, it is often optimal to grow functional oxides in particular directions to maximize their properties for a specific application. But these thin film techniques offer more than orientation control; customization of the film structure down to the atomic‐layer level is possible. Numerous examples of the controlled epitaxial growth of oxides with perovskite and perovskite‐related structures, including superlattices and metastable phases, are shown. In addition to integrating functional oxides with conventional semiconductors, standard semiconductor practices involving epitaxial strain, confined thickness, and modulation doping can also be applied to oxide thin films. Results of fundamental scientific importance as well as results revealing the tremendous potential of utilizing functional oxide thin films to create devices with enhanced performance are described.
In Situ Measurement of Shrinkage During Postreaction Sintering of Reaction‐Bonded Silicon Nitride
Authors: Wakihara Toru , Yabuki Hiromasa , Tatami Junichi , Komeya Katsutoshi , Meguro Takeshi , Hyuga Hideki , Kita Hideki
Published: August 2008

The reaction‐bonding technique is one of the major fabrication processes of silicon nitride (Si3N4) ceramics, which has received much attention as a cost‐effective process due to the use of cheap Si powder as a raw material. Many studies on the development of this method have been performed in order to improve their properties; however, the sintering shrinkage behavior, which is a very important information to optimize the firing condition, has not been well clarified. In this study, we focused on the reaction‐bonding technique of the Si–Y2O3–Al2O3 system. At first, reaction‐bonded body of the Si–Y2O3–Al2O3 system was prepared, and then its postreaction sintering shrinkage behavior was investigated by in situ dilatometry. It was found that no shrinkage occurred from 1400° to 1600°C due to grain rearrangement in the reaction‐bonded Si3N4 body. Furthermore, the shrinkage of the reaction‐bonded Si3N4 started around 1750°C, which is a higher temperature compared with the green body of conventional Si3N4 powder. The restriction of shrinkage seems to result from neck growth and strong aggregation among reacted Si3N4 particles.
Self‐Assembly of Dandelion‐Like Hydroxyapatite Nanostructures Via Hydrothermal Method
Authors: Lak Aidin , Mazloumi Mahyar , Mohajerani Matin , Kajbafvala Amir , Zanganeh Saeid , Arami Hamed , Sadrnezhaad S. K.
Published: August 2008

Self‐assembled dandelion‐like hydroxyapatite (HAp) nanostructures were successfully synthesized via a mild template‐free hydrothermal process, using ethylenediaminetetraacetic acid (EDTA) as the surfactant. The obtained dandelion‐like HAp nanostructures were between 5 and 8 μm in diameter and were composed of radially oriented nanorods with an average diameter of about 200 nm. The X‐ray diffraction analysis and Fourier transform infrared spectroscopy were used to characterize the crystalline phase and purity of the synthesized nanostructures. The Brunauer–Emmett–Teller surface area of the dandelion‐like nanostructures was measured to be about 39 m2/g. The results of thermal analysis revealed that dandelion‐like HAp nanostructures have appropriate thermal stability up to 1200°C. Scanning electron microscopy and transmission electron microscopy analyses showed that EDTA plays an important role in obtaining the dandelion‐like morphology, because without it, only monodispersed HAp nanoparticles with an average diameter of about 125 nm were formed. The mechanism for the formation of dandelion‐like HAp nanostructures was suggested based on the radial self‐assembly of Ca‐EDTA molecular complexes.
Synthesis and Pressureless Sintering of Zirconium Phosphate Ceramics
Authors: Chen Fei , Shen Qiang , Schoenung Julie M. , Zhang Lianmeng
Published: August 2008

Zirconium phosphate (ZrP2O7) powder is synthesized by direct reaction between ZrO2 and H3PO4 and is used to prepare ZrP2O7 ceramics with MgO and Al2O3 as the sintering additives by pressureless sintering technique. The mechanism of reaction between ZrO2 and H3PO4 is analyzed. The results suggest that the reaction between ZrO2 and H3PO4 is completed at 250°C and ZrP2O7 is stable up to ∼1200°C. At temperatures above ∼1200°C, decomposition starts to occur, resulting in the formation of Zr2O(PO4)2. After exposure to temperatures as high as 1500°C, decomposition is still not complete. The pure ZrP2O7 ceramic, however, is difficult to sinter to high density. In contrast, ZrP2O7 ceramics with MgO and Al2O3 sintering additives can be liquid‐phase sintered to relative densities of 90%–96% at sintering temperatures of 1250°–1500°C, without significant decomposition. The microstructure is observed by scanning electron microscopy. The effect of density, phosphate glass phase, and grain growth on bending strength is analyzed. Because of the abnormal grain growth and microcracking of ZrP2O7 ceramics, the bending strength first increases and then decreases as a function of the sintering temperature.
A spatial linkage between dams and non‐native fish species in Hokkaido, Japan
Authors: Han M. , Fukushima M. , Fukushima T.
Published: August 2008

Abstract –  The native and non‐native freshwater fish species richness as well as the proportion of native fish species to overall fish species were examined to test a hypothesis of a spatial linkage between the distributions of dams and non‐native fishes based on survey data collected in rivers and streams in Hokkaido, Japan. Non‐native fish species have steadily increased in Hokkaido since the mid 1970s, as indicated by the decreasing proportion of native fish species per fish survey. Non‐native species richness was significantly higher in areas above dams (i.e., reservoirs and their inlet streams) compared to areas without dams. As a result, the proportion of native fish species was lower above dams. This proportion was lower in developed and agricultural areas compared with forest areas, although both native and non‐native species richness were higher in areas with development and agriculture. Non‐native cyprinids, catfish and snakehead occurred primarily in a particular river basin with the largest drainage area, the longest history of reclamation and highest human population in the island. Non‐native salmonids on the other hand, occurred in forest areas at higher elevations and their occurrence was associated with the existence of dams. There was a spatial linkage between the distribution of dams and non‐native species, although it was applicable only to salmonids. The management of dams and reservoirs needs a strategy to prevent further expansion of exotic salmonids such as rainbow and brown trout. These species can be a significant threat to native Japanese salmonids as a result of various biological mechanisms.
Increased fear‐ and stress‐related anxiety‐like behavior in mice lacking tuberoinfundibular peptide of 39 residues
Authors: Fegley D. B. , Holmes A. , Riordan T. , Faber C. A. , Weiss J. R. , Ma S. , Batkai S. , Pacher P. , Dobolyi A. , Murphy A. , Sleeman M. W. , Usdin T. B.
Published: August 2008

Tuberoinfundibular peptide of 39 residues (TIP39) is synthesized by two groups of neurons, one in the subparafascicular area at the caudal end of the thalamus and the other in the medial paralemniscal nucleus within the lateral brainstem. The subparafascicular TIP39 neurons project to a number of brain regions involved in emotional responses, and these regions contain a matching distribution of a receptor for TIP39, the parathyroid hormone 2 receptor (PTH2‐R). We have now evaluated the involvement of TIP39 in anxiety‐related behaviors using mice with targeted null mutation of the TIP39 gene (Tifp39). Tifp39−/− mice (TIP39‐KO) did not significantly differ from wild‐type (WT) littermates in the open field, light/dark exploration and elevated plus‐maze assays under standard test conditions. However, the TIP39‐KO engaged in more active defensive burying in the shock‐probe test. In addition, when tested under high illumination or after restraint, TIP39‐KO displayed significantly greater anxiety‐like behavior in the elevated plus‐maze than WT. In a Pavlovian fear‐conditioning paradigm, TIP39‐KO froze more than WT during training and during tone and context recall but showed normal fear extinction. Disruption of TIP39 projections to the medial prefrontal cortex, lateral septum, bed nucleus of the stria terminalis, hypothalamus and amygdala likely account for the fear‐ and anxiety‐related phenotype of TIP39‐KO. Current data support the hypothesis that TIP39 modulates anxiety‐related behaviors following environmental provocation.
Updated analysis of the dynamical relation between asteroid 2003 EH1 and comets C/1490 Y1 and C/1385 U1
Authors: Micheli Marco , Bernardi Fabrizio , Tholen David J.
Published: August 2008

The asteroid 2003 EH1, proposed as the parent body of the Quadrantid meteor shower, is thought to be the remnant of a past cometary object, tentatively identified with the historical comets C/1490 Y1 and C/1385 U1. In this work, we use recovery astrometry to extend the observed arc of 2003 EH1 from 10 months to about 5 years, enough to exclude the proposed direct relationship of the asteroid with both of the comets.
Rapid optical and X-ray timing observations of GX 339-4: flux correlations at the onset of a low/hard state
Authors: Gandhi P. , Makishima K. , Durant M. , Fabian A. C. , Dhillon V. S. , Marsh T. R. , Miller J. M. , Shahbaz T. , Spruit H. C.
Published: August 2008

We present the discovery of optical/X-ray flux correlations on rapid time-scales in the low/hard state of the Galactic black hole GX 339-4. The source had recently emerged from outburst and was associated with a relatively faint counterpart with mag V ≈ 17. The optical [Very Large Telescope (VLT)/ULTRACAM] and X-ray (Rossi X-ray Timing Explorer) data show a clear positive cross-correlation function (CCF) signal, with the optical peak lagging X-rays by ∼150 ms, preceded by a shallow rise and followed by a steep decline along with broad anticorrelation dips. An examination of the light curves shows that the main CCF features are reproduced in superpositions of flares and dips. The CCF peak is narrow and the X-ray autocorrelation function (ACF) is broader than the optical ACF, arguing against reprocessing as the origin for the rapid optical emission. X-ray flaring is associated with spectral hardening, but no corresponding changes are detected around optical peaks and dips. The variability may be explained in the context of synchrotron emission with interaction between a jet and a corona. The complex CCF structure in GX 339-4 has similarities to that of another remarkable X-ray binary XTE J1118+480, in spite of showing a weaker maximum strength. Such simultaneous multiwavelength, rapid timing studies provide key constraints for modelling the inner regions of accreting stellar sources.
Bringing rights home: time to start a family?
Authors: Sedley Stephen
Published: August 2008

Proposals for a new constitutional settlement have highlighted issues, many of them factitious, about the Human Rights Act. This paper suggests that the relationship of rights to duties is poorly understood, and that the majority of recognised rights already carry corresponding duties, but that to try to make the enjoyment of rights conditional on the fulfilment of duties is neither principled nor practicable. It is suggested that, using mutual respect as a sounder basis, a larger Bill of Rights can be contemplated. But good constitutions cannot be willed into being: pending the arrival of a constitutional moment, reform is likely to be a process of interest-group wrangling in which the most that can be looked for are some modest but necessary reforms.
Development and psychometric testing of a new geriatric spiritual well‐being scale
Authors: Dunn Karen S.
Published: August 2008

Aims and objectives.  Assess the psychometric properties of a new geriatric spiritual well‐being scale (GSWS), specifically designed for older adults.

Background.  Religiosity and spiritual wellness must be measured as two distinct concepts to prevent confounding them as synonymous among atheist and agnostic population.

Design.  A test–retest survey design was used to estimate the psychometric properties.

Methods.  A convenience sample of 138 community‐dwelling older adults was drawn from the inner city of Detroit. Data were collected using telephone survey interviews. Data analyses included descriptive statistics, structural equation modelling, reliability analyses, and point‐biserial correlations.

Results.  The factorial validity of the proposed model was not supported by the data. Fit indices were χ2 = 185.98, d.f. = 98, P < 0.00, goodness‐of‐fit index of 0.85, comparative fit index of 0.87 and root mean error of approximation of 0.08, indicating a mediocre fit. Reliability statistics for the subscales ranged from being poor (0.36) to good (0.84) with an acceptable overall scale alpha of 0.76. Participants’ performance stability and criterion‐related validity were also supported.

Conclusions.  The GSWS is an age‐specific assessment tool that was developed specifically to address a population’s cultural diversity. Future research endeavors will be to test the psychometric properties of this scale in culturally diverse older adult populations for further instrument development.

Relevance to clinical practice.  Nurses need to recognize that agnostics/atheists have spiritual needs that do not include religious beliefs or practices. Thus, assessing patients’ religious beliefs and practices prior to assessing spiritual well‐being is essential to prevent bias.
Delirium and older people: what are the constraints to best practice in acute care?
Authors: Day Jenny , Higgins Isabel , Koch Tina
Published: August 2008

An Australian research team conducted a six‐month acute care pilot study in a medical ward of a large hospital in New South Wales.

Aim.  To explore ways health practitioners might redesign their practice to include prevention, early detection and management of delirium in older people based on the best current practice.

Method and design.  Participatory action research (PAR) was selected as the best approach for involving ward staff to make sustainable clinical practice decisions. The PAR group comprised research academics and eight clinicians from the ward. Thirteen PAR sessions were held over 5 months. Clinicians described care of patients with delirium. Stories were analysed to identify constraints to best practice. Following PAR group debate about concerns and issues, there were actions toward improved practice taken by clinicians.

Relevance to clinical practice.  The following constraints to best practice were identified: delayed transfer of patients from the Emergency Department; routine ward activities were not conducive to provision of rest and sleep; assisting with the patient’s orientation was not possible as relatives were not able to accompany and/or stay with the older patient. Underreporting of delirium and attributing confusion to dementia was viewed as an education deficit across disciplines. A wide range of assessment skills was identified as prerequisites for working in this acute care ward, with older people and delirium. Clinicians perceived that management driven by length of a patient’s stay was incongruent with best practice delirium care which required more time for older patients to recover from delirium. Two significant actions towards practice improvement were undertaken by this PAR group: (i) development of a draft delirium alert prevention protocol and (ii) a separate section of the ward became a dedicated space for the care of patients with delirium. A larger study is being planned across a variety of settings.
Formal and informal care in relation to activities of daily living and self‐perceived health among older care‐dependent individuals in Norway
Authors: Dale Bjørg , Sævareid Hans Inge , Kirkevold Marit , Söderhamn Olle
Published: August 2008

Background.  Research about formal care of older home‐dwelling people in the Nordic countries is comprehensive, while research on informal care has been less inclusive.

Aim.  To describe self‐reported activities of daily living and perceived health, and to relate them to amount and types of formal and informal care received by a group of care‐dependent, home‐dwelling older individuals in Norway.

Design and methods.  A sample consisting of 242 persons aged 75+ years receiving home nursing services. Data were collected by means of structured interviews with questions about activities of daily living (ADL), amount and types of formal and informal care and demographic variables. Descriptive statistics, chi‐square test, Mann‐Whitney U‐test and multiple stepwise regression were used in the analyses.

Results.  ADL dependency was the only predictor for explaining quantity of home nursing received. Those who received a generous amount of formal care also received a lot of care and support from informal networks. The type of care from the two sources differed. The home nurses performed PADL tasks. While the informal caregivers offered help with IADL tasks.

Conclusion.  This study of receiving help in this group of older people in Norway shows that formal and informal care resources complement one another.
Photophysical Properties of Coumarin‐7 Dye: Role of Twisted Intramolecular Charge Transfer State in High Polarity Protic Solvents
Authors: Satpati Ashis Kumar , Kumbhakar Manoj , Nath Sukhendu , Pal Haridas
Published: August 2008

Photophysical studies on coumarin‐7 (C7) dye in different protic solvents reveal interesting changes in the properties of the dye on increasing the solvent polarity (Δf; Lippert–Mataga solvent polarity parameter) beyond a critical value. Up to Δf∼0.31, the photophysical properties of the dye follow good linear correlations with Δf. For Δf >∼0.31, however, the photophysical properties, especially the fluorescence quantum yields (Φf), fluorescence lifetimes (τf) and nonradiative rate constants (knr), undergo large deviations from the above linearity, suggesting an unusual enhancement in the nonradiative decay rate for the excited dye in these high polarity protic solvents. The effect of temperature on the τf values of the dye has also been investigated to reveal the mechanistic details of the deexcitation mechanism for the excited dye. Studies have also been carried out in deuterated solvents to understand the role of solute–solvent hydrogen bonding interactions on the photophysical properties of the dye. Observed results suggest that the fluorescence of the dye originates from the planar intramolecular charge transfer (ICT) state in all the solvents studied and the deviations in the properties in high polarity solvents (Δf >∼0.31) arise due to the participation of a new deexcitation channel associated with the formation of a nonfluorescent twisted intramolecular charge transfer (TICT) state of the dye. Comparing present results with those of a homologous dye coumarin 30 (C30; Photochem. Photobiol., 2004, 80, 104), it is indicated that unlike in C30, the TICT state of the C7 dye does not experience any extra stability in protic solvents compared to that in aprotic solvents. This has been attributed to the presence of intramolecular hydrogen bonding between the NH group (in the 3‐benzimidazole substituent) of the C7 dye and its carbonyl group, which renders an extra stability to the planar ICT state, making the TICT state formation relatively difficult. Qualitative potential energy diagrams have been proposed to rationalize the differences observed in the results with C7 and C30 dyes in high polarity protic solvents.
Temperature Effects on Survival and DNA Repair in Four Freshwater Cladoceran Daphnia Species Exposed to UV Radiation
Authors: Connelly Sandra J. , Moeller Robert E. , Sanchez Guillermo , Mitchell David L.
Published: August 2008

The biological responses of four freshwater daphniid species, Daphnia middendorffiana, D. pulicaria, D. pulex and D. parvula, to a single acute dose of ultraviolet B radiation (UVB) were compared. In addition to survival, we compared the induction of DNA damage (i.e. cyclobutane pyrimidine dimers) between species as well as the ability to repair this damage in the presence or absence of photoreactivating light. All four species showed high levels of shielding against DNA damage when compared to damage induced in purified DNA dosimeters at the same time and dose. Significant variation in survival was observed between species depending on temperature and light conditions. Contrary to our expectations, all species showed significantly higher survival and light‐dependent DNA damage removal rates at 10°C compared to 20°C, suggesting that the enhanced rate of photoenzymatic repair (PER) at the lower temperature contributed significantly to the recovery of these organisms from UVB. PER was highly effective in promoting survival of three of the four species at 10°C, but at 20°C it was only partially effective in two species, and ineffective in two others. None of the species showed significant dark repair at 20°C and only D. pulicaria showed a significant capacity at 10°C. Two species, D. middendorffiana and D. pulex, showed some short‐term survival at 10°C in absence of PER despite their inability to repair any appreciable amount of DNA damage in the dark. All species died rapidly at 20°C in absence of PER, as predicted from complete or near‐absence of nucleotide excision repair (NER). Overall, the protective effects of tissue structure and pigmentation were similar in all Daphnia species tested and greatly mitigated the absorption of UVB by DNA and its damaging effects. Surprisingly, the visibly melanotic D. middendorffiana was not better shielded from DNA damage than the three non‐melanotic species, and in fact suffered the highest damage rates. Melanin content in this species was not temperature dependent under the experimental growth conditions, and so did not contribute to temperature‐dependent responses. It is evident that different species within the same genus have developed diverse biological responses to UVB. Our data strongly suggest that DNA damage is lethal to Daphnia and that photoenzymatic repair is the primary mechanism for removing these lesions. In the absence of light, few species are capable of removing any DNA damage. Surprisingly, the single species in which significant excision repair was detected did so only at reduced temperature. This temperature‐dependence of excision repair is striking and may reflect adaptations of certain organisms to stress in a complex and changing environment.
Self‐Reflection and the Cognitive Control of Behavior: Implications for Learning
Authors: Marcovitch Stuart , Jacques Sophie , Boseovski Janet J. , Zelazo Philip David
Published: August 2008

ABSTRACT— In this article, we suggest that self‐reflection and self‐control—studied under the rubric of “executive function” (EF)—have the potential to transform the way in which learning occurs, allowing for the relatively rapid emergence of new behaviors. We describe 2 lines of research that indicate that reflecting on a task and its affordances helps children to respond flexibly in a more top‐down fashion despite interference from prior learning or perceptually salient aspects of the task. Research on A‐not‐B tasks with infants and young children revealed that postswitch flexibility is an inverted U‐shaped function of number of preswitch trials. Overlearning may provide additional opportunities for reflection, in part by freeing up cognitive resources as behavior becomes automatized. Findings from the Flexible Item Selection Task with preschoolers and adults revealed that, although labeling the relevant dimension facilitates performance, performance declines when participants are prohibited from labeling. Labeling one’s perspective on a situation not only helps make that perspective an explicit object of consideration, but it may also help children access more abstract conceptual descriptions of a stimulus. Research on EF has broad implications for the way in which human learning differs from learning in other species and the way in which human learning may change over the course of development.
Bicanalicular double silicone intubation in external dacryocystorhinostomy and canaliculoplasty for distal canalicular obstruction
Authors: Hwang Sang Won , Khwarg Sang In , Kim Jong Hyun , Choung Ho Kyung , Kim Nam Ju
Published: August 2008

Purpose:  We aimed to evaluate the effectiveness of bicanalicular double silicone intubation in dacryocystorhinostomy (DCR) and canaliculoplasty for distal or common canalicular obstruction.

Methods:  We reviewed the medical records of patients with distal or common canalicular obstruction who had undergone bicanalicular double silicone intubation (insertion of two tubes into each canaliculus) during external DCR and canaliculoplasty. We reviewed the records of subjects who had undergone the same surgery with a bicanalicular single intubation as control material. The tubes were removed at around 6 months after surgery. Anatomical and functional success rates of patients who were followed up for > 2 months after the removal of tube(s) were evaluated. In addition, complications related to the silicone tube were evaluated.

Results:  Data for 60 eyes of 45 patients in the double‐intubation group and 69 eyes of 65 patients in the single‐intubation group were retrieved. The double‐intubation group showed higher anatomical success rates (96.5%) than the single‐intubation group (85.5%). Functional success was achieved by 53 (88.3%) of 60 eyes in the double‐intubation group and 56 (81.2%) of 69 eyes in the single‐intubation group. There was no significant difference in complication rates between the two groups.

Conclusions:  Bicanalicular double silicone intubation for DCR and canaliculoplasty may be an effective mode of treatment for patients with distal or common canalicular obstruction.
Phacoemulsification in vitrectomized eyes: results using a ‘phaco chop’ technique
Authors: Sachdev Nishant , Brar Gagandeep Singh , Sukhija Jaspreet , Gupta Vishali , Ram Jagat
Published: August 2008

Purpose:  To evaluate the intraoperative and early postoperative complications of phacoemulsification using a ‘phaco chop’ technique in previously vitrectomized eyes.

Methods:  A prospective interventional case series. Seventy‐five previously vitrectomized eyes of 73 consecutive patients underwent phacoemulsification using a ‘phaco chop’ technique via clear corneal incision. Patients were observed for any intraoperative or early postoperative complications.

Results:  Fifty‐four eyes (72%) had predominant nuclear sclerosis or posterior subcapsular cataract. The intraoperative findings included intraoperative miosis [seen in 21 eyes (28%)] and posterior capsule plaques [in 15 eyes (20%)]. No other significant intraoperative complication (posterior capsule rupture, zonular lysis or dropped nuclei) was observed. In the early postoperative period, one patient had massive serous choroidal detachment, which resolved with conservative treatment. Mean preoperative visual acuity (LogMar scale) was 0.74, which improved to 0.36 postoperatively (p < 0.001).

Conclusion:  Phacoemulsification using a ‘phaco chop’ technique is a safe procedure in vitrectomized eyes.
Limited Inhibitory Effects of Oseltamivir and Zanamivir on Human Sialidases
Authors: Hata Keiko , Koseki Koichi , Yamaguchi Kazunori , Moriya Setsuko , Suzuki Yasuo , Yingsakmongkon Sangchai , Hirai Go , Sodeoka Mikiko , von Itzstein Mark , Miyagi Taeko
Published: August 2008

Oseltamivir (Tamiflu) and zanamivir (Relenza), two extensively used clinically effective anti-influenza drugs, are viral sialidase (also known as neuraminidase) inhibitors that prevent the release of progeny virions and thereby limit the spread of infection. Recently mortalities and neuropsychiatric events have been reported with the use of oseltamivir, especially in pediatric cases in Japan, suggesting that these drugs might also inhibit endogenous enzymes involved in sialic acid metabolism, including sialidase, sialyltransferase, and CMP-synthase, in addition to their inhibitory effects on the viral sialidase. The possible inhibition could account for some of the rare side effects of oseltamivir. However, there has been little direct evidence in regard to the sensitivities of animal sialidases to these drugs. Here, we examined whether these inhibitors might indeed affect the activities of human sialidases, which differ in primary structures and enzyme properties but possess tertiary structures similar to those of the viral enzymes. Using recombinant enzymes corresponding to the four human sialidases identified so far, we found that oseltamivir carboxylate scarcely affected the activities of any of the sialidases, even at 1 mM, while zanamivir significantly inhibited the human sialidases NEU3 and NEU2 in the micromolar range (

K
i

, 3.7 ± 0.48 and 12.9 ± 0.07 μM, respectively), providing a contrast to the low nanomolar concentrations at which these drugs block the activity of the viral sialidases.
Differential Azole Antifungal Efficacies Contrasted Using a
Saccharomyces cerevisiae
Strain Humanized for Sterol 14α-Demethylase at the Homologous Locus
Authors: Parker J. E. , Merkamm M. , Manning N. J. , Pompon D. , Kelly S. L. , Kelly D. E.
Published: August 2008

Inhibition of sterol-14α-demethylase, a cytochrome P450 (CYP51, Erg11p), is the mode of action of azole antifungal drugs, and with high frequencies of fungal infections new agents are required. New drugs that target fungal CYP51 should not inhibit human CYP51, although selective inhibitors of the human target are also of interest as anticholesterol agents. A strain of
Saccharomyces cerevisiae
that was humanized with respect to the amino acids encoded at the
CYP51
(
ERG11
) yeast locus (BY4741:huCYP51) was produced. The strain was validated with respect to gene expression, protein localization, growth characteristics, and sterol content. The MIC was determined and compared to that for the wild-type parental strain (BY4741), using clotrimazole, econazole, fluconazole, itraconazole, ketoconazole, miconazole, and voriconazole. The humanized strain showed up to >1,000-fold-reduced susceptibility to the orally active azole drugs, while the topical agents showed no difference. Data from growth kinetic measurements substantiated this finding but also revealed reduced effectiveness against the humanized strain for the topical drugs. Cellular sterol profiles reflected the decreased susceptibility of BY4741:huCYP51 and showed a smaller depletion of ergosterol and accumulation of 14α-methyl-ergosta-8, 24(28)-dien-3β-6α-diol than the parental strain under the same treatment conditions. This strain provides a useful tool for initial specificity testing for new drugs targeting CYP51 and clearly differentiates azole antifungals in a side-by-side comparison.
Posaconazole Combined with Amphotericin B, an Effective Therapy for a Murine Disseminated Infection Caused by
Rhizopus oryzae
Authors: Rodríguez M. Mar , Serena Carolina , Mariné Marçal , Pastor F. Javier , Guarro Josep
Published: August 2008

In a murine model of disseminated zygomycosis, low doses of amphotericin B (0.3 mg/kg body weight/day) combined with posaconazole (40 mg/kg/day) prolonged survival and reduced tissue burden with respect to that of controls and that of both drugs administered alone. Results were similar to those obtained with amphotericin B given alone at 0.8 mg/kg/day.
In Vitro and In Vivo Evaluations of Oxacillin Efficiency against
mecA
-Positive Oxacillin-Susceptible
Staphylococcus aureus
Authors: Ikonomidis Alexandros , Michail George , Vasdeki Afroditi , Labrou Maria , Karavasilis Vasilis , Stathopoulos Constantinos , Maniatis Antonios N. , Pournaras Spyros
Published: August 2008

Community-type
Staphylococcus aureus
strains that are positive for
mecA
and PBP2a but appear phenotypically susceptible to oxacillin are increasingly reported worldwide. Four
S. aureus
clinical isolates carrying the
mecA
gene with oxacillin MICs of <2 μg/ml were tested for oxacillin efficiency by population analyses and experimental thigh infections. These isolates harbored staphylococcal cassette chromosome
mec
type IV and belonged to two genotypes. Two of the four isolates were found by population analysis to be truly oxacillin susceptible. All four isolates exhibited significant reductions in the numbers of colonies grown after dicloxacillin treatment of experimental thigh infections, as also did a
mecA
-negative
S. aureus
control strain. These observations indicate that some of the phenotypically oxacillin susceptible
mecA
-positive
Staphylococcus aureus
isolates may be at least partially responsive to oxacillin.
Neisseria meningitidis
Escape from the Bactericidal Activity of a Monoclonal Antibody Is Mediated by Phase Variation of
lgtG
and Enhanced by a Mutator Phenotype
Authors: Bayliss Christopher D. , Hoe J. Claire , Makepeace Katherine , Martin Patricia , Hood Derek W. , Moxon E. Richard
Published: August 2008

Bacteria adapt to environmental changes through high-frequency switches in expression of specific phenotypes. Localized hypermutation mediated by simple sequence repeats is an important mechanism of such phase variation (PV) in
Neisseria meningitidis
. Loss or gain of nucleotides in a poly(C) tract located in the reading frame results in switches in expression of
lgtG
and determines whether a glucose or a phosphoethanolamine (PEtn) is added at a specific position in the inner core lipopolysaccharide (LPS). Monoclonal antibody (MAb) B5 is bactericidal for
N. meningitidis
strain 8047 when PEtn is present in the inner core LPS and
lgtG
is switched “off.” Escape from the bactericidal activity of this antibody was examined by subjecting strain 8047 to multiple cycles of growth in the presence of MAb B5 and human serum. Escape variants with alterations in the
lgtG
repeat tract rapidly accumulated in bacterial populations during selection with this antibody. Strain 8047 was outcompeted in this assay by the 8047 Δ
mutS
strain due to the elevated PV rate of this mismatch repair mutant and hence the greater proportion of preexisting phase variants of
lgtG
in the inoculum. This
mutS
mutant was also more virulent than strain 8047 during escape from passive protection by MAb B5 in an in vivo infant rat model of bacteremia. These results provide an example of how PV rates can modulate the occurrence and severity of infection and have important implications for understanding the evolution of bacterial fitness in species subject to environmental variations that occur during persistence within and transmission between hosts.
Increased Susceptibility to
Mycobacterium avium
in Hemochromatosis Protein HFE-Deficient Mice
Authors: Gomes-Pereira Sandra , Rodrigues Pedro Nuno , Appelberg Rui , Gomes Maria Salomé
Published: August 2008

Mycobacterium avium
is an opportunistic infectious agent in immunocompromised patients, living inside macrophage phagosomes. As for other mycobacterial species, iron availability is a critical factor for
M. avium
survival and multiplication. Indeed, an association between host secondary iron overload and increased susceptibility to these mycobacteria is generally acknowledged. However, studies on the impact of primary iron overload on
M. avium
infection have not been performed. In this work, we used animal models of primary iron overload that mimic the human disease hereditary hemochromatosis. This pathology is characterized by increased serum transferrin saturation with iron deposition in parenchymal cells, mainly in the liver, and is most often associated with mutations in the gene encoding the molecule HFE. In this paper, we demonstrate that mice of two genetically determined primary iron overload phenotypes, Hfe
−/−
and β2m
−/−
, show an increased susceptibility to experimental infection with
M. avium
and that during infection these animals accumulate iron inside granuloma macrophages. β2m
−/−
mice were found to be more susceptible than Hfe
−/−
mice, but depleting Hfe
−/−
mice of CD8
+
cells had no effect on resistance to infection. Overall, our results suggest that serum iron, rather than total liver iron, levels have a considerable impact on susceptibility to
M. avium
infection.
The p50 Subunit of NF-κB Is Critical for In Vivo Clearance of the Noninvasive Enteric PathogenCitrobacter rodentium
Authors: Dennis Alison , Kudo Takahiro , Kruidenier Laurens , Girard Francis , Crepin Valerie F. , MacDonald Thomas T. , Frankel Gad , Wiles Siouxsie
Published: August 2008

Citrobacter rodentium, a natural mouse pathogen, belongs to the family of extracellular enteric pathogens that includes enteropathogenicEscherichia coli(EPEC) and enterohemorrhagicE. coli(EHEC).C. rodentiumshares many virulence factors with EPEC and EHEC and relies on attaching-and-effacing lesion formation for colonization and infection of the gut. In vivo,C. rodentiuminfection is characterized by increased epithelial cell proliferation, mucosal thickening, and a TH1-type immune response, but with protective immunity believed to be mediated by serum immunoglobulin G (IgG). In this work, we characterize the immune response and pathology of mice lacking the p50 subunit of the transcription factor nuclear factor kappa B (NF-κB) duringC. rodentiuminfection. We show that p50−/−mice are unable to clearC. rodentiuminfection. Furthermore, these animals show a reduced influx of immune cells into infected colonic tissue and greater levels of mucosal hyperplasia and the cytokines tumor necrosis factor alpha and gamma interferon. Surprisingly, despite being unable to eliminate infection, p50−/−mice showed markedly higher levels of anti-CitrobacterIgG and IgM, suggesting that antibody alone is not responsible for bacterial clearance. These data also demonstrate that non-NF-κB-dependent defenses are insufficient to controlC. rodentiuminfection, and hence, the NF-κB p50 subunit is critical for defense against this noninvasive pathogen.
ON THE LAGRANGIAN AND HAMILTONIAN FORMULATION OF A SCALAR FREE FIELD THEORY AT NULL INFINITY
Authors: DAPPIAGGI CLAUDIO
Published: August 2008

In the framework of asymptotically flat spacetimes, we discuss the notion of a covariant scalar free field at null infinity. We construct the associated equations of motion exploiting either the theory of induced representations or the white noise analysis. Eventually, we prove that these equations can also be derived as the minimum of a suitable Lagrangian and that a real scalar field theory at null infinity admits a Hamiltonian formulation.
ON A MINIMIZING PROPERTY OF THE HOPF SOLITON IN THE FADDEEV–SKYRME MODEL
Authors: ISOBE TAKESHI
Published: August 2008

We study local minimizing solutions for the Faddeev–Skyrme problem on the 3-sphere with radius R. We show that for [Formula: see text] the Hopf soliton is a local minimizing solution and all the other local minimizing solutions near the Hopf soliton are obtained as the composition of isometries of S3 with the Hopf soliton.
SURFACE PROPERTIES AND CATALYTIC PERFORMANCE OF ACTIVATED CARBON FIBERS SUPPORTED TiO2 PHOTOCATALYST
Authors: YANG HUIFEN , FU PINGFENG
Published: August 2008

Activated carbon fibers supported TiO 2 photocatalyst ( TiO 2/ACF) in felt-form was successfully prepared with a dip-coating process using organic silicon modified acrylate copolymer as a binder followed by calcination at 500°C in a stream of Ar gas. The photocatalyst was characterized by SEM, XRD, XPS, FTIR, and BET surface area. Most of carbon fibers were coated with uniformly distributed TiO 2 clusters of nearly 100 nm. The loaded TiO 2 layer was particulate for the organic binder in the compact film was carbonized. According to XPS and FTIR analysis, amorphous silica in carbon grains was synthesized after carbonizing organic silicon groups, and the Ti – O – Si bond was formed between the interface of loaded TiO 2 and silica. Additionally, the space between adjacent carbon fibers still remained unfilled after TiO 2 coating, into which both UV light and polluted solutions could penetrate to form a three-dimensional environment for photocatalytic reactions. While loaded TiO 2 amount increased to 456 mg TiO 2/1 g ACF, the TiO 2/ACF catalyst showed its highest photocatalytic activity, and this activity only dropped about 10% after 12 successive runs, exhibiting its high fixing stability of coated TiO 2.
STUDY OF THE STOICHIOMETRIC RATIO OF ONE-STEP ELECTRODEPOSITED CuInSe2 FILMS ON ITO/SODA-LIME GLASS
Authors: YAO N. J. , HUANG S. M. , CHU J. B. , ZHU H. B. , SUN Z. , CHEN Y. W.
Published: August 2008

Copper indium diselenide ( CuInSe 2) thin films were grown on indium–tin oxide (ITO)/soda-lime glass using a one-step cathodic electrodeposition process at potentials lower than -0.6 V vs SCE, and in the presence of a large excess of In 3+. The source solution contained CuCl 2, InCl 3, and H 2 SeO 3 complexed by citric acid. The concentration of InCl 3 in the electrochemical bath affected the structure, composition, stoichiometric ratio, and morphological properties of electrodeposited films. CuInSe 2 films with a chalcopyrite structure and quite good stoichiometry were directly electrodeposited from a solution of 20 mM InCl 3, 5 mM CuCl 2, and 8 mM H 2 SeO 3. Annealing of these CuInSe 2 films in the temperature range from 300°C to 500°C improves their crystallinity and increases their grain size. Good chalcopyrite CuInSe 2 films with a (112) preferential orientation suitable for the production of efficient solar cells are obtained after annealing at 500°C. The formation mechanism of the ternary CuInSe 2 compound during the electrodeposition process was discussed.