bluuebunny/crossref_metadata_2025 huggingface dataset:
Long-term data on the reproduction and maintenance of a colony of common marmosets (Callithrix jacchus jacchus) 1972-1983
Authors: Box H. O. , Hubrecht R. C.
Published: July 2007

We have used our laboratory records to compare data on the reproduction and maintenance of common marmosets in different colonies and to provide additional information on the species in captivity. Data are presented for a period of 12 years. This was long enough to allow information on longevity, mortality, aggression and incest. In addition 543 infants were born from a total of 202 births. No seasonality was found and the highest proportion of births overall was that of triplets. A significantly greater proportion of males was born, but perinatal mortality reduced this to a proportion of 52·2% surviving males. The interbirth interval for all normal births ranged from 145 to 382 days, with a median of 158 days. There was no evidence that interbirth intervals increased with age. The proportion of non-breeding pairs was small (4 out of 28) and progesterone assays showed that these females were ovulating.
Recirculation anaesthesia for laboratory fish
Authors: Brown L. A.
Published: July 2007

An economic reliable long-term recirculation anaesthesia system for laboratory fish is described. Anaesthesia of channel catfish ( Ictalurus punctatus Rafinesque) was induced within 60 s and was maintained for up to 40 min using tricaine methanesulphonate; recovery occurred within 30-60 s. Various surgical procedures were performed on the fish. No deaths were recorded. All water-quality parameters tested over 19 days use of the system remained stable except for total ammonia nitrogen and, by calculation, un-ionized ammonia which increased to a maximum of 0·23 mg/1.
Simple method for bleeding the unanaesthetized rat by tail venipuncture
Authors: Omaye S. T. , Skala J. H. , Gretz M. D. , Schaus E. E. , Wade C. E.
Published: July 2007

A technique is described for the intermittent collection of blood from the rat tail. By using commonly available equipment, blood samples can easily be obtained from rats without the need for anaesthesia. The development of this technique makes the rat more readily available as an animal model for repeated withdrawals of small blood samples for pharmacokinetic or bioavailability evaluations.
Balancing rigour and relevance: researchers’ contributions to children’s mental health policy in Canada
Authors: Waddell Charlotte , Shepherd Cody A. , Lavis John N. , Lomas Jonathan , Abelson Julia , Bird-Gayson Twylla
Published: July 2007

English

We investigated researchers’ experiences of, and views on, interacting with policy makers, using children’s mental health as an example. Qualitative methods were used to interview university researchers, policy researchers, and research funders. Participants spoke of contributions to policy that went beyond interaction with policy makers. We describe how participants became motivated, developed approaches, and created new environments to contribute to policy. Our findings suggest that university researchers should challenge their peers to better recognise and support policy interaction and public engagement. Both university and policy researchers must balance academic rigour and policy relevance to make meaningful contributions to policy.
The production and management of evidence for public service reform
Authors: Shepherd Jonathan
Published: July 2007

English

Public services depend on the production, distribution and application of evidence of effectiveness. Existing strengths of this process in the UK include many university schools closely associated with services, a strategic partnership of Research Councils, some service-specific excellence institutes and successful models for evidence management, particularly in health. However, there is little recognition that this research is fundamental to society. There are few formal connections between the national science base, the Research Councils and public services designed to focus research effort or to increase evidence quality. Components of evidence management systems need to be recognised as such, integrated and connected. At each stage, practical reforms are identified, designed to ensure that services continuously develop in response to reliable new knowledge.
Septin Expression in Proliferative Retinal Membranes
Authors: Xin Xiaorong , Pache Mona , Zieger Barbara , Bartsch Ingrid , Prünte Christian , Flammer Josef , Meyer Peter
Published: July 2007

We undertook this study to evaluate the expression of septin family members SEPT5, SEPT8, and SEPT11 in proliferative retinal membranes. Epiretinal membranes (ERM) were obtained from seven patients with proliferative vitreoretinopathy (PVR) and from four patients and four postmortem eyes with proliferative diabetic retinopathy (PDR). Subretinal membranes (SRM) were obtained from one patient and six postmortem eyes. Membranes were examined by immunohistochemical staining of paraffin sections using polyclonal antibodies against SEPT5, SEPT8, and SEPT11 and an ABC detection system. SEPT8 expression was detected in all ERM and SRM, with an exceptionally strong expression of 100% for ERM of PVR, 63% for PDR membranes, and 57% for SRM. SEPT11 was identified in 91% of all cases, with strong expression of 14%, 25%, and 14% in ERM of PVR, PDR, and SRM, respectively. SEPT5 was seen in 50% of all cases; strong immunostaining was found in only one case of PVR membranes. Our finding suggests a role for members of the septin family in the development of proliferative retinal membranes.
Angiogenesis Is Not Impaired in Connective Tissue Growth Factor (CTGF) Knock-out Mice
Authors: Kuiper Esther J. , Roestenberg Peggy , Ehlken Christoph , Lambert Vincent , van Treslong-de Groot Henny Bloys , Lyons Karen M. , Agostini Hans-Jürgen T. , Rakic Jean-Marie , Klaassen Ingeborg , Van Noorden Cornelis J. F. , Goldschmeding Roel , Schlingemann Reinier O.
Published: July 2007

Connective tissue growth factor (CTGF) is a member of the CCN family of growth factors. CTGF is important in scarring, wound healing, and fibrosis. It has also been implicated to play a role in angiogenesis, in addition to vascular endothelial growth factor (VEGF). In the eye, angiogenesis and subsequent fibrosis are the main causes of blindness in conditions such as diabetic retinopathy. We have applied three different models of angiogenesis to homozygous CTGF−/− and heterozygous CTGF+/− mice to establish involvement of CTGF in neovascularization. CTGF−/− mice die around birth. Therefore, embryonic CTGF−/−, CTGF+/−, and CTGF+/+ bone explants were used to study in vitro angiogenesis, and neonatal and mature CTGF+/− and CTGF+/+ mice were used in models of oxygen-induced retinopathy and laser-induced choroidal neovascularization. Angiogenesis in vitro was independent of the CTGF genotype in both the presence and the absence of VEGF. Oxygen-induced vascular pathology in the retina, as determined semi-quantitatively, and laser-induced choroidal neovascularization, as determined quantitatively, were also not affected by the CTGF genotype. Our data show that downregulation of CTGF levels does not affect neovascularization, indicating distinct roles of VEGF and CTGF in angiogenesis and fibrosis in eye conditions.
Spatial and temporal organisation of small mammal communities in the Monte desert, Argentina
Authors: Corbalán Valeria , Ojeda Ricardo
Published: July 2007

The coexistence of desert small mammals can be explained by differences in
microhabitat use, morphology, body size, diet and foraging. The aim of this
study was to quantify the structure of small mammal assemblages and the seasonal
fluctuations in their abundance using mark – recapture techniques in
habitats of different structural heterogeneity (mesquite forest, creosotebush
community, and sand dunes) in the temperate Monte desert of Argentina.
Habitat heterogeneity was characterised by 10 vegetation variables. The
mesquite forest and the creosotebush community showed the highest diversity
and habitat heterogeneity. The relative abundance of each species underwent
remarkable variations between habitats. The sigmodontinae rodents
Graomys griseoflavus and Eligmodontia typus were the dominant species in the
mesquite forest and sand dunes, respectively, whereas no dominant species
was observed in the creosotebush habitat. Abundance varied throughout the
year, reaching maximum density in autumn and spring.
Suckling attempts during winter by two non-filial Steller sea lion pups (Eumetopias jubatus)
Authors: Porter Boyd T. , Trites Andrew W.
Published: July 2007

Milk stealing and fostering care is rare among mammals (Packer et al. 1992). Such behaviour can benefit neonates and possibly the nursing foster mother (Roulin 2002, 2003). However, it also likely comes at a cost to the fostering mother and her dependent young. Neonates may increase their chances of survival by sneak-suckling unrelated females, or by obtaining milk with the consent of mothers of other neonates. However, chances are greater that females protective of their limited milk resources will aggressively prevent unrelated young from suckling. Risks of being bitten, attacked or killed by adult females presumably outweigh the potential benefits that might be achieved by sneak-suckling.
Seasonal variation in the diet of the bat Carollia perspicillata (Chiroptera: Phyllostomidae) in an Atlantic Forest area in southeastern Brazil
Authors: Mello Marco Aurelio R. , Schittini Gilberto M. , Selig Pedro , Bergallo Helena G.
Published: July 2007

Carollia perspicillata feeds primarily on plants of the family Piperaceae, as
reported in the literature. Although this preference occurs throughout this
species’ geographic range, in some situations they may eat other items. This
study analyzed variations in the feeding habits of this bat species over an
18-month period. Although C. perspicillata consumed mostly Piper plants,
they also ate other fruits (e.g. Cecropia and Solanum plants), and insects as
well. Food choice followed a seasonal pattern, related to the availability of
Piper plants. The seasonal absence of these fruits may have necessitated bats to
eat alternative items.
A note on three new cytotypes of Lophuromys flavopunctatus sensu lato (Rodentia, Muridae) from Tanzania
Authors: Corti Marco , Castiglia Riccardo , Verheyen Walter
Published: July 2007

Three different new cytotypes of the L. flavopunctatus sensu lato species group
are reported for Tanzania, suggesting chromosomal rearrangements are
coupled or favour divergence within this area. These are characterised by
2n=68 and NFa=90 (the most widespread), 2n=68 and NFa=84, and 2n=70
NFa=86. The karyotypes present striking differences from the others reported
for this species complex.
Responses of Contemporary and Historical Waterhemp (Amaranthus tuberculatus) Accessions to Glyphosate
Authors: Volenberg Dean S. , Patzoldt William L. , Hager Aaron G. , Tranel Patrick J.
Published: July 2007

Anecdotal reports suggest waterhemp is becoming more difficult to control with glyphosate. Waterhemp accessions collected primarily in Illinois before 1996, in 1998 to 1999, and in 2003, were evaluated for differential responses to glyphosate treatment. The pre-1996 group consisted of 10 accessions, whereas the 1998 to 1999 and 2003 groups consisted of 45 accessions each. Plants 10 to 12 cm in height from each waterhemp accession were treated with 0 or 220 g ae ha−1glyphosate. Although shoot dry biomass 14 d after treatment, expressed as a percentage of the untreated, varied within and among accessions, the mean responses of the three groups were similar. However, when glyphosate responses were divided into 10 arbitrary classes (0 to 10, 11 to 20, …, and 81 to 90; > 91% of untreated), the number of plants within each class differed among groups. Most notably, the proportion of plants in the range of 0 to 30% of the untreated control decreased with time when progressing from the pre-1996 to the 2003 accessions. The relative frequency of waterhemp plants that were ≥ 100% of the untreated plants (i.e., uninjured by glyphosate) in the pre-1996, 1998 to 1999, and 2003 groups were 5, 6, and 5%, respectively. In a separate trial, waterhemp populations that exhibited the least sensitivity to glyphosate at 220 g ha−1were controlled by 870 g ha−1glyphosate. These results suggest that waterhemp, as a whole, within Illinois has not become less sensitive to glyphosate over the past few years. However, the proportion of plants that are most sensitive to glyphosate may be decreasing within populations.
Ranking Nonindigenous Weed Species by Their Potential to Invade the United States
Authors: Parker Chris , Caton Barney P. , Fowler Larry
Published: July 2007

Because of the large number of potentially invasive species, and the time required to complete weed risk assessments (WRAs) with the use of the current, mandated system in the United States, species need to be prioritized for assessment and possible listing as Federal Noxious Weeds. Our objective was to rank the potential invasiveness of weedy or pest plant species not yet naturalized in the United States. We created a new model of invasiveness (hereafter the U.S. weed-ranking model) based on scoring factors within four elements: (1) invasiveness potential, or likelihood to exhibit invasive behavior; (2) geographic potential, or habitat suitability; (3) damage potential, or likely impact; and (4) entry potential, or likelihood to be introduced. The ranking score was the product of the four elements. We scored 250 species satisfactorily, from a list of 700 +. We analyzed model sensitivity to scoring factors, and compared results to those from a WRA model for Hawaii. For species not in cultivation in the United States, the top 25 species included a mix of annuals, perennials, sedges, shrubs, and trees. Most had exhibited invasive behavior in at least several other countries. Because of greater entry potential scores, the highest-scoring species were weeds in cultivation. Twenty-nine such species, out of 44 total, had scores greater than the highest scoring species not in cultivation. In comparison to the Hawaii WRA model, correlation and regression analyses indicated that the U.S. weed-ranking model produced similar, but not exact, results. The ranking model differs from other WRAs in the inclusion of entry potential and the use of a multiplicative approach, which better suited our objectives and United States regulations. Two highly ranked species have recently been listed as Federal Noxious Weeds, and we expect most top-tier species to be similarly assessed.
Extreme Ionic and Temperature Effects on Germination of Weeping Alkaligrass (Puccinellia distans), Nuttall's Alkaligrass (Puccinellia nuttalliana) and Kentucky Bluegrass (Poa pratensis)
Authors: Tarasoff Catherine S. , Ball Daniel A. , Mallory-Smith Carol A.
Published: July 2007

The introduced species weeping alkaligrass, and the native species Nuttall's alkaligrass, two of the most salt-tolerant C3 grasses found in arid and semiarid environments of western North America, occur within the Grande Ronde valley of eastern Oregon. Both species occur as weeds within Kentucky bluegrass seed fields and subsequently as grass seed contaminants. Two separate germination experiments were conducted to understand better the seed germination biology of these two species compared to Kentucky bluegrass under negative water potentials or high temperature conditions. Results of these studies indicate that although all three species benefited from an ionic enhancement associated with NaCl, weeping alkaligrass was the most drought and salt tolerant of the three species. Dry seeds of weeping alkaligrass were also particularly tolerant to high temperatures with no differences in germination at temperatures below 50 C, indicating that seed viability under nonirrigated field conditions should be unaffected by high soil temperatures. Under soil temperature conditions as high as 40 C, moist Kentucky bluegrass seeds had the greatest germination rates, indicating that this species should benefit from irrigation more than the other two species.
A Model for Predicting Common Cocklebur (Xanthium strumarium) Emergence in Soybean
Authors: Norsworthy Jason K. , Oliveira Marcos J.
Published: July 2007

The objective of this research was to develop a model to predict common cocklebur seedling emergence in spring tillage and no-spring-tillage systems in the presence and absence of a soybean canopy. A Weibull function was used to accumulate heat units (i.e., growing degree days) at a 2.5 cm soil depth on days when mean soil temperature, soil water potential, and soil thermal fluctuation were above established thresholds. The base temperature, soil water potential, and soil thermal fluctuation thresholds used for model development were 17 C, −100 kPa, and 7.5 C, respectively. A single function adequately described common cocklebur seedling emergence in the presence and absence of drill-seeded soybean from data combined over an artificial (2004) and natural seedbank (2005) (R2= 0.986). Model parameterization differed between the artificial and natural seedbank in the absence of spring tillage, but emergence was adequately described, regardless of soybean presence. Separate parameter estimates for the artificial and natural seedbanks were needed to adequately describe emergence in the system without spring tillage (R2= 0.975 to 0.984). The ability of the model to account for reduced emergence when soil moisture is limited or when daily thermal fluctuation requirements are not met could assist practitioners with assessments associated with field scouting for weeds as well as other management decisions.
Suppression of CtpA in Mouseearcress Produces a Phytotoxic Effect: Validation of CtpA as a Target for Herbicide Development
Authors: Sophia Chen Yun-Chia , Fabbri Brad J. , CaJacob Claire A. , Anderson John C. , Duff Stephen M. G.
Published: July 2007

To validate carboxyterminal processing protease of D1 protein (CtpA) as a target for herbicide discovery, CtpA sense mRNAs were overexpressed to suppress the internal level of CtpA protein in mouseearcress plants. Using antibodies raised against recombinant CtpA protein, we demonstrated that we have generated transgenic mouseearcress plants with reduced levels of CtpA protein and plants with elevated levels of CtpA protein. Transgenic plants with severely reduced levels of CtpA protein exhibited a bleached and chlorotic phenotype and stunted growth. The mutant phenotypes were enhanced by bright illumination. However, plants with a slight reduction of CtpA protein did not exhibit the mutant phenotype and could not be distinguished from wild-type plants under normal growth conditions. Several CtpA enzyme inhibitors were shown to have herbicidal activity in planta. Interestingly, plants producing excessive amount of CtpA protein were shown to be resistant to these inhibitors. Our results suggest that CtpA is essential for plant growth and development, but a reduced amount of CtpA is sufficient to carry out its essential function. CtpA may be a good target for herbicide development, but very high levels of inhibition may be required to produce a herbicidal effect. In addition, overexpressing CtpA in target plants might provide a mechanism for producing plants resistant to the herbicide.
Reproduction of Dandelion (Taraxacum officinale) in a Higher CO2 Environment
Authors: McPeek Tamara M. , Wang Xianzhong
Published: July 2007

Dandelion is a cosmopolitan weed of economic and environmental significance because of its negative effects on crop yield and the large amount of herbicides used for its control in agricultural, residential, and recreational areas in North America. Asexual dandelion plants, which are apomictic and produce genetically identical seeds, provide a great experimental model for biological studies, such as examination of its reproductive responses to global environmental changes. In a growth chamber experiment, we investigated how elevated CO2 affected reproduction and seed dispersal properties in dandelion. Dandelion plants were grown at ambient (370 µmol mol−1) or elevated (730 µmol mol−1) CO2 until reproductive maturity. Results showed that dandelion plants examined in our study produced 83% more inflorescences and 32% more achenes, i.e., single-seed fruits, per plant at elevated than at ambient CO2. Seeds from elevated CO2-grown plants were significantly heavier and had a higher germination percentage, leading to larger seedlings and earlier establishment in the subsequent generation. Furthermore, achenes from plants grown at elevated CO2 had characteristics, such as higher stalks at seed maturity, longer beaks, and larger pappi, which would increase the distance of seed dispersal by wind. In addition to these elevated CO2-induced changes in reproductive properties, dandelion has a number of inherent characteristics, e.g., high competitiveness and adaptations to disturbance, that would increase its vegetative and reproductive success in a higher CO2 environment. Consequently, dandelion can potentially become more widespread and noxious as atmospheric CO2 continues to rise because of human activities.
Assessment of Psychophysiological Stress Reactions During a Traumatic Reminder in Patients Treated With EMDR
Authors: Sack Martin , Lempa Wolfgang , Lamprecht Friedhelm
Published: July 2007

This study investigates changes of stress-related psychophysiological reactions after treatment with EMDR. Sixteen patients with posttraumatic stress disorder (PTSD) following type I trauma underwent psychometric and psychophysiological assessment during exposure to script-driven imagery before and after EMDR and at 6-month follow-up. Psychophysiological assessment included heart rate (HR) and heart rate variability (HRV) during a neutral task and during trauma script listening. PTSD symptoms as assessed by questionnaire decreased significantly after treatment and during follow-up in comparison to pretreatment. After EMDR, stress-related HR reactions during trauma script were significantly reduced, while HRV indicating parasympathetic tone increased both during neutral script and during trauma script. These results were maintained during the follow-up assessment. Successful EMDR treatment may be associated with reduced psychophysiological stress reactions and heightened parasympathetic tone.
Current Status and Future Directions for EMDR Research
Authors: Maxfield Louise
Published: July 2007

This review provides the groundwork for a basic understanding of articles written about eye movement desensitization and reprocessing (EMDR), including a brief overview of theory and practice. It documents EMDR’s established efficacy in the treatment of posttraumatic stress disorder and specifies specific subsets of this population in need of further investigation. The article also provides a review of recent studies evaluating a range of EMDR’s clinical applications and outlines new directions for research investigations and for developments in clinical practice. It concludes with an overview of current research evaluating pre- and post-neurobiological changes, and mechanisms of action. Specific recommendations for future areas of investigations are outlined, and rigorous evaluation is strongly encouraged.
Diabetes Management Issues for Patients With Chronic Kidney Disease
Authors: Cavanaugh Kerri L.
Published: July 2007

IN BRIEF

Chronic kidney disease (CKD) is common and can be found in up to 23% of patients with diabetes. The recommended hemoglobin A1c goal for these patients is also < 7.0%. Medication therapy for diabetes may require dose adjustments or may be contraindicated in patients with CKD. Assessment and management of comorbid diseases, including hypertension, hyperlipidemia,anemia, hyperphosphatemia, and hyperparathyroidism, is important in the care of patients with diabetes and CKD. Multidisciplinary care may provide the optimal system for maximizing care of these complex patients.
Biofunctionalization of Gold Nanoparticles
Authors: Zheng Ming , Huang Xueying
Published: July 2007

The sections in this article are

Introduction

General Synthetic Routes

Direct Synthesis of Ligand‐protectedAuNPs

Strongly Ionic Ligand‐protectedAuNPs

Weakly Ionic Ligand‐protectedAuNPs

AuNPsProtected with Neutral Ligands

Ligand Exchange Reaction

Preparative‐scale Synthesis and Solution‐phase Characterization ofDNA‐directed Nanoparticle Assemblies

Bifunctional Proteins for Programmable Assembly of Nanoparticles

Strategies for Eliminating Nonspecific Interactions and Enabling Specific Binding with Biomolecules

Biological Applications

Nucleic Acids

Proteins

Cells and Virus

Acknowledgments
Cover Picture: Reconstructing a Nanoporous Metal in Three Dimensions: An Electron Tomography Study of Dealloyed Gold Leaf (Adv. Eng. Mater. 7/2007)
Authors: Rösner H. , Parida S. , Kramer D. , Volkert C. A. , Weissmüller J.
Published: July 2007

Back‐Cover‐Page: Nanoporous gold, prepared by electrochemical dissolution of Ag from commercial white gold leaf, was investigated by HAADF‐STEM tomography. The picture shows a surface‐rendering of a fully connected network structure composed of single‐crystalline gold ligaments and pores reconstructed in three dimensions. The study advertises the power of electron tomography as an emerging tool for elucidating the three‐dimensional microstructure of materials with a nanoscale resolution. Further Information can be found in the paper by Rösner et al. on page 535.
Stable, Low‐Temperature Discotic Nematic Superstructures by Incorporating a Laterally Substituted Sidearm in Hexakis(phenylethynyl)benzene Discogens
Authors: Chien S.‐C. , Chen H.‐H. , Chen H.‐C. , Yang Y.‐L. , Hsu H.‐F. , Shih T.‐L. , Lee J.‐J.
Published: July 2007

A new strategy for preparing room‐temperature discotic nematic materials is proposed and developed stepwise to improve various discotic nematic properties. This approach replaces one sidearm of the discotic hexakis(4‐hexyloxyphenylethynyl)benzene with a tris(alkoxy) sidearm, 1‐ethynyl‐2,3,4‐tris(hexyloxybenzene), to lower transition temperatures, manipulate discotic nematic ranges, and preserve the discotic nematic superstructure while preventing column formation. Although symmetry considerations play a role in the resulting mesogenic properties, steric hindrance and van der Waals interactions are ascribed to the superior discotic nematic properties of the newly prepared discogens containing a laterally substituted sidearm.
Low‐Work‐Function Surface Formed by Solution‐Processed and Thermally Deposited Nanoscale Layers of Cesium Carbonate
Authors: Huang J. , Xu Z. , Yang Y.
Published: July 2007

Nanostructured layers of Cs2CO3 are shown to function very effectively as cathodes in organic electronic devices because of their good electron‐injection capabilities. Here, we report a comprehensive study of the origin of the low work function of nanostructured layers of Cs2CO3 prepared by solution deposition and thermal evaporation. The nanoscale Cs2CO3 layers are probed by various characterization methods including current–voltage (I–V) measurements, photovoltaic studies, X‐ray photoelectron spectroscopy (XPS), UV photoelectron spectroscopy (UPS), and impedance spectroscopy. It is found that thermally evaporated Cs2CO3 decomposes into CsO2 and cesium suboxides. The cesium suboxides dope CsO2, yielding a heavily doped n‐type semiconductor with an intrinsically low work function. As a result, devices fabricated using thermally evaporated Cs2CO3 are relatively insensitive to the choice of the cathode metal. The reaction of thermally evaporated Cs2CO3 with Al can further reduce the work function to 2.1 eV by forming an Al–O–Cs complex. Solution‐processed Cs2CO3 also reduces the work function of Au substrates from 5.1 to 3.5 eV. However, devices prepared using solution‐processed Cs2CO3 exhibit high efficiency only if a reactive metal such as Al or Ca is used as the cathode metal. A strong chemical reaction occurs between spin‐coated Cs2CO3 and thermally evaporated Al. An Al–O—Cs complex is formed as a result of this chemical reaction at the interface, and this layer significantly reduces the work function of the cathode. Finally, impedance spectroscopy results prove that this layer is highly conductive.
Textured Tubular Nanoparticle Structures: Precursor‐Templated Synthesis of GaN Sub‐micrometer Sized Tubes
Authors: Ding S. , Lu P. , Zheng J.‐G. , Yang X. F. , Zhao F. L. , Chen J. , Wu H. , Wu M. M.
Published: July 2007

Porous and sub‐micrometer tubes made of textured GaN nanoparticles have been synthesized by an in situ chemical reaction and characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and photoluminescence (PL) and Raman spectroscopies. The in situ reaction involves thermal decomposition and nitridation of 1D gallium oxyhydroxide (GaOOH) at temperatures in the range of 700–900 °C. The 1D shape of the precursor GaOOH is maintained in the resultant GaN tubes. The GaN nanocrystals (estimated to be about 15 nm in size) are found to be highly oriented with respect to each other in the tube structure, with the [110] GaN direction parallel to the tube axis. The growth mechanism of the tube structure has also been studied. β‐Ga2O3 is found to be an intermediate phase between the starting GaOOH precursor and the final GaN product. The growth mechanism involves decomposition of GaOOH, which produces β‐Ga2O3 tubes with hollow interiors, and nitridation of β‐Ga2O3, which leads to growth of textured GaN nanocrystals. Based on the growth mechanism, tubular structures with either quasi‐circular or rectangular cross section are selectively synthesized by controlling the heating rate and calcination temperature. This in situ chemical reaction method provides a new route for synthesizing 1D hollow nanostructures.
Das thermische Verhalten der Phenole. (2. Mitteilung(. Über die Thermodynamik und den Mechanismus des thermischen Zerfalls des Phenols und seiner Homologen)
Authors: Hagemann A.
Published: July 2007

1. Die Umwandlungen des Phenols und des Metakresols werden thermodynamisch nach der Nernstschen Näherungsformel bestimmt und die erhaltenen Gleichgewichte diskutiert. – 2. Der Reaktionsmechanismus des thermischen Zerfalls wird auf Grund experimenteller Ergebnisse erklärt.
Reihenversuche mit Natriumsuperoxyd‐Atemgeräten. Zur Kenntnis der Wirkungsweise von Natriumsuperoxyd‐Atemgeräten I
Authors: Stampe G. , Horng E.
Published: July 2007

Inhalt: Durch systematische Versuche mit Natriumsuperoxydpatronen unter ganz gleichartigen Bedingungen wird bei gegebenem Superoxydpräparat das Optimum des Patronenaufbaus ermittelt.
Preparation and characterization of polyacrylamide cryogels produced from a high‐molecular‐weight precursor. I. Influence of the reaction temperature and concentration of the crosslinking agent
Authors: Ivanov Roman V. , Lozinsky Vladimir I. , Noh Seok Kyun , Han Sung Soo , Lyoo Won Seok
Published: July 2007

A new type of cryogel was prepared through a reaction of high‐molecular‐weight polyacrylamide (viscosity‐average molecular weight ≈ 3 × 106 Da) with glutaraldehyde in a moderately frozen aqueous medium. The influence of the crosslinking agent concentration and temperature of the reaction on the gel fraction yield, swelling characteristics, and morphology of the cryogels was investigated. The dependence of the gel fraction yield on the reaction temperature was bell‐shaped. The recognized regularities of the formation of this new type of polyacrylamide cryogel based on a high‐molecular‐weight precursor were very similar to those observed earlier for polyacrylamide cryogels synthesized through the cryopolymerization of monomeric precursors. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Preparation of atactic poly(vinyl alcohol)/sodium alginate blend nanowebs by electrospinning
Authors: Lee Young Jae , Shin Dong Soo , Kwon Oh Wook , Park Won Ho , Choi Han Gon , Lee Yong Rok , Han Sung Soo , Noh Seok Kyun , Lyoo Won Seok
Published: July 2007

Through the blending of a rigid polymer, sodium alginate (SA), and a flexible polymer, atactic poly(vinyl alcohol) (PVA), with various ratios of SA and PVA and through the electrospinning of SA/PVA solutions, SA/PVA blend nanowebs were successfully prepared. The structure and morphology of the SA/PVA blend nanowebs were investigated through a series of instrumental analyses. Through the examination of the morphological variations of each blend web, it was found that with only PVA, the electrospun nanowebs had very uniform and fine fiber structures, but the SA/PVA blend nanowebs had a mixture of large beads and fibers, which were generated with increasing SA content. A thermal analysis indicated that the endothermic peaks of the SA/PVA blend nanowebs decreased with an increase in the SA content. The SA content was determined by the observation of the changes in the SA peak intensity via Fourier transform infrared spectroscopy. The tensile strength decreased with increasing SA content. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Effect of structure on the tribological properties of polytetrafluoroethylene drawn uniaxially at the melting point
Authors: Liu Xiaoxia , Li Tongsheng , Liu Xujun , Lv Renguo , Cong Peihong
Published: July 2007

Drawn polytetrafluoroethylene (PTFE) with different draw ratio and sliding directions were investigated using a pin‐on‐disc tester. The anisotropy of tribological properties for drawn PTFE was found and the lowest friction coefficient and wear rate were reached when sliding along draw direction. The higher the orientation degree was, the smaller the friction coefficient and the wear rate were. The morphologies of the samples and debris were characterized by scanning electron microscope. The results showed that the fiber structure of drawn PTFE was formed and the morphologies of debris were different from undrawn PTFE. The results indicated that the bulk orientation structure of drawn PTFE played an important role on its tribological properties. The shear force was parallel with the oriented fibrils formed by drawing when sliding along draw direction and a better smoothing worn surface occurred easily, which resulted in the low friction coefficient. The fiber formed by drawing prevented effectively the large flake‐like debris from formation, which reduced the wear rate of drawn PTFE. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Study of the thermomechanical and electrical properties of conducting composites containing natural rubber and carbon black
Authors: Oliveira Fernando A. , Alves Neri , Giacometti José A. , Constantino Carlos J. L. , Mattoso Luiz H. C. , Balan Ana M. O. A. , Job Aldo E.
Published: July 2007

This work describes the preparation and characterization of composite materials obtained by the combination of natural rubber (NR) and carbon black (CB) in different percentages, aiming to improve their mechanical properties, processability, and electrical conductivity, aiming future applications as transducer in pressure sensors. The composites NR/CB were characterized through optical microscopy (OM), DC conductivity, thermal analysis using differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMA), thermogravimetry (TGA), and stress–strain test. The electrical conductivity varied between 10−9 and 10 S m−1, depending on the percentage of CB in the composite. Furthermore, a linear (and reversible) dependence of the conductivity on the applied pressure between 0 and 1.6 MPa was observed for the sample with containing 80 wt % of NR and 20% of CB. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Synthesis of microphase‐separated solvent‐free solid polymer electrolyte nanocomposite films using amphiphilic urethane acrylate precursors
Authors: Kim Ju‐Young , Han Kweon‐Hyung , Suh Kyung‐Do , Ihn Kyo‐Jin
Published: July 2007

A new solvent‐free solid polymer electrolyte (SPE) films could be fabricated through bulk copolymerization process of amphiphilic urethane acrylate nonionomer (UAN). Amphiphilic UAN chain having polypropylene oxide‐based hydrophobic segment and polyethylene oxide‐based hydrophilic segment can not only dissolve lithium salt by complex formation with lithium cations but also be copolymerized with various monomers to form microphase‐separated polymeric matrix. Unlike conventional SPE systems showing higher conductivity with polar polymers and polar solvents, our SPE films prepared by copolymerization of UAN and hydrophobic monomers exhibited relatively higher conductivity. Dissolving lithium salts in UAN/hydrophobic monomer mixtures caused hydrophilic/hydrophobic microphase separation, which was more favorable for ionic conduction of lithium ions, resulting in the higher ionic conductivity than the SPE films fabricated using UAN/hydrophobic monomer mixture. This microphase‐separated structure of SPE films could be also confirmed by transmission electron microscope (TEM) images. Ionic conductivity of our SPE films could be also improved by dispersing clay minerals within SPE films. Three types of clay having different surface properties were used to fabricate clay/SPE nanocomposite films. Ionic conductivity of nanocomposite films depended on dispersibliity of clay nanoparticles with a SPE film, which was confirmed by measuring X‐ray diffraction and TEM. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Surface Studies of Gas Sensing Metal Oxides
Authors: Batzill Matthias , Diebold Ulrike
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Enantioselective Organocatalysis Using SOMO Activation
Authors: Beeson Teresa D. , Mastracchio Anthony , Hong Jun‐Bae , Ashton Kate , MacMillan David W. C.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Organic Semiconductor Lasers
Authors: Samuel I. D. W. , Turnbull G. A.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
AT1Receptor Ligands: Virtual‐Screening‐Based Design with TOPP Descriptors, Synthesis, and Biological Evaluation of Pyrrolidine Derivatives
Authors: Lamanna Claudia , Catalano Alessia , Carocci Alessia , Di Mola Antonia , Franchini Carlo , Tortorella Vincenzo , Vanderheyden Patrick M. L. , Sinicropi Maria S. , Watson Kimberly A. , Sciabola Simone
Published: July 2007

As a continuing effort to establish the structure–activity relationships (SARs) within the series of the angiotensin II antagonists (sartans), a pharmacophoric model was built by using novel TOPP 3D descriptors. Statistical values were satisfactory (PC4:r2=0.96,q2(5randomgroups)=0.84; SDEP=0.26) and encouraged the synthesis and consequent biological evaluation of a series of new pyrrolidine derivatives. SAR together with a combined 3D quantitative SAR and high‐throughput virtual screening showed that the newly synthesized 1‐acyl‐N‐(biphenyl‐4‐ylmethyl)pyrrolidine‐2‐carboxamides may represent an interesting starting point for the design of new antihypertensive agents. In particular, biological tests performed on CHO‐hAT1cells stably expressing the human AT1receptor showed that the length of the acyl chain is crucial for the receptor interaction and that the valeric chain is the optimal one.
Metronidazole–Flavonoid Derivatives as Anti‐Helicobacter pyloriAgents with Potent Inhibitory Activity against HPE‐Induced Interleukin‐8 Production by AGS Cells
Authors: Li Huan‐Qiu , Xu Chen , Li Hong‐Sen , Xiao Zhu‐Ping , Shi Lei , Zhu Hai‐Liang
Published: July 2007

Three series of metronidazole–flavonoid derivatives were generated and evaluated for antimicrobial activity againstH. pylori. Among these compounds, high anti‐H. pyloriactivities were observed in isoflavones derivatives4–7,19, and20but exhibited no inhibitory activity against other sorts of bacteria and fungi, for example,Streptococcus pneumoniae, Bacillus subtilis, Escherichia coli, Pseudomonas fluorescence, andAspergillus niger. Genistein derivative6with the potent activity (MIC=0.39 μg mL−1) was >50‐fold more than metronidazole, and comparable to the positive control amoxicillin. Additionally, compound6can significantly attenuate the increase in interleukin‐8 (IL‐8) levels in the AGS cells stimulated byH. pyloriwater extract (HPE) at concentrations of 15, 30, and 60 μmol L−1, which did not show any effects on the cell viability.
Active surveillance for selected patients with renal masses
Authors: Abou Youssif Tamer , Kassouf Wassim , Steinberg Jordan , Aprikian Armen G. , Laplante Micheal P. , Tanguay Simon
Published: July 2007

BACKGROUND.

The objective of the current study was to evaluate the outcome of a surveillance strategy in patients with renal masses.

METHODS.

The medical records of patients with renal masses diagnosed between January 1992 and May 2006 were reviewed retrospectively. In all, 45 patients with renal masses under observation were identified. Of these, 35 patients with 44 renal masses measuring <4 cm in dimension at the time of diagnosis and who were followed for at least 6 months were included in the review. Patients elected observation because of age, comorbidity, solitary kidney, or bilateral renal masses. Medical records were reviewed to determine tumor size and volume changes as well as clinical progression requiring treatment, the development of metastatic disease, or death.

RESULTS.

A total of 35 patients (21 men and 14 women) with 44 renal masses were observed for a mean follow‐up of 47.6 months. The mean age of these patients was 71.8 years. The majority of the patients (89%) were asymptomatic at the time of diagnosis. The mean and median initial tumor dimension was 2.2 cm and 2.2 cm, respectively (range, 0.5–4 cm). Of the 35 patients, 2 (5.7%) were lost to follow‐up, 8 (22.9%) underwent surgical resection, and 9 (25.7%) died of other causes. The mean dimension growth rate was 0.21 cm/year (range, 0.03–1.9 cm/year). The mean and median volume growth rate was 2.7 cc/year and 1.4 cc/year, respectively. Progression to metastatic disease was identified in 2 patients (5.7%).

CONCLUSIONS.

The majority of renal masses will grow if observed and some may require treatment. Initial tumor size cannot predict the natural history of renal masses. A small but non‐negligible risk of developing metastatic disease exists in this patient population. Further research should focus on the role of biopsy and on identification of prognostic parameters allowing more accurate prediction of tumor growth and metastasis. Cancer 2007. © 2007 American Cancer Society.
Single DNA Molecule Isolation and Trapping in a Microfluidic Device
Authors: Kumemura Momoko , Collard Dominique , Yamahata Christophe , Sakaki Naoyoshi , Hashiguchi Gen , Fujita Hiroyuki
Published: July 2007

This paper presents a systematic method to isolate and trap long single DNA segments between integrated electrodes in a microfluidic environment. Double stranded λ‐DNA molecules are introduced in a microchip and are isolated by electrophoretic force through microfluidic channels. Downstream, each individual molecule is extended and oriented by ac dielectrophoresis (900 kHz, 1 MV m−1) and anchored between aluminium electrodes. With a proper design, a long DNA segment (up to 10 μm) can be instantly captured in stretched conformation, opening way for further assays.
A reinforced movable boundary multiplexing scheme with adaptive interpolation: Modelling and performance evaluation
Authors: Meempat Gopalakrishnan , Sundareshan Malur K.
Published: July 2007

A novel multiplexing scheme for integrated networks characterized by the coexistence of circuitswitched and packet‐switched traffic is described in this paper. The new scheme is realized by a reinforcement of the basic movable boundary hybrid‐switching technique, by incorporating an adaptive interpolation within the circuit‐switched subsystem. The adaptation mechanism is controlled by the level of congestion in the packet queue. A precise queueing model for the multiplexer is developed and an analytical evaluation of the key performance parameters of interest, namely the loss probability and expected delay of the packet‐switched subsystem, and the freeze‐out fraction of the circuit‐switched subsystem, is conducted. The results of several numerical studies are presented to describe the performance of the multiplexer under different conditions. Of particular significance resulting from these studies is the trade‐off between the freeze‐out fraction of the circuit‐switched subsystem and the loss probability of the packet‐switched subsystem; this trade‐off may be exploited in a systematic design of the interrated multiplexer tailored to specific applications.
A multilevel framework for the attribute description of telecommunication services
Authors: de Smedt Alex , Hellemans Patrick , Roncheiti Luigi , Täubig Klaus
Published: July 2007

Telecommunication services are traditionally described from the terminal viewpoint, including the user interaction with the service, as well as the specific terminal characteristics to the network that it is meant for. Also traditionally the instance of the telecommunication service was a call and a connection as a one‐to‐one couple.

Nowadays networks with powerful multimedia/multiconnection/multiparty capabilities require that a telecommunication service should not be described any more as a conglomerate, but by its main service elements, which in turn are supported by other service elements, so that a service may be built up by building blocks in a levelled model.

The criteria to be considered to find these elements are the user viewpoint, the information coding (or terminal) viewpoint and the network access viewpoint. This leads to the telecommunication service, party, party edge, user service module and abstract service module as pure user‐dependent service elements, the service module for the terminal aspect, and the access connection element for transfer of the information over the network.

All these basic service elements are ordered in a levelled structure called a multilevel framework. Each level or co‐level represents a service element type which may be instantiated as a service object, and which is described statically by a table of attributes. Attributes for each level are listed and clarified.

An example describing a well‐known service is given to illustrate the use of the framework.

The views expressed in this document have been developed by the RACE 2044 MAGIC.

RACE: Research into Advanced Communication Technologies for Europe. MAGIC: Multi‐service Applications Governing Integrated Control.

The concepts presented are related to Release 2 and 3 for BISDN as defined in ITU‐T.
Equivalent bandwidth and related admission criteria for ATM systems—a performance study
Authors: Rege Kiran M.
Published: July 2007

The concept of the equivalent bandwidth of a source seems highly attractive for characterizing ATM traffic sources as it can be used to treat constant as well as variable bit rate sources within a common framework. In this paper we review the concept of equivalent bandwidth based on asymptotic results and study the performance of a few admission criteria which use this concept in one way or another. A major finding is that with appropriate refinements to account for the possible statistical multiplexing gain at small to moderate buffer sizes, the well‐known conservatism of the asymptotic equivalent bandwidth based criteria can be overcome. We also discuss how these criteria would perform in practical situations where the traffic sources are incompletely characterized, or where they are specified in terms of leaky‐bucket based traffic descriptors.