bluuebunny/crossref_metadata_2025 huggingface dataset:
The Cities We Need
Authors: Bendiner-Viani Gabrielle
Published: February 2024

An expressive book of prose and photographs that reveals the powerful ways our everyday places support our shared belonging.

Where would you take someone on a guided tour of your neighborhood? In The Cities We Need, photographer and urbanist Gabrielle Bendiner-Viani introduces us to the complex, political, and eminently personable stories of residents who answered this question in Brooklyn, New York, and Oakland, California. Their universal stories and Bendiner-Viani's evocative images illuminate what's at stake in our everyday places—from diners to churches to donut shops. In this culmination of two decades of research and art practice, Bendiner-Viani intertwines the personal, historical, and photographic to present us with placework, the way that unassuming places foster a sense of belonging and, in fact, do the essential work of helping us become communities.

In this unique book, Bendiner-Viani makes visible how seemingly unimportant places can lay the foundation for a functional interconnected society, so necessary for both public health and social justice. The Cities We Need explores both what we gain in these spaces and what we risk losing as they are threatened by gentrification, large-scale development, and most recently the COVID-19 pandemic. Ultimately, Bendiner-Viani shows us how to understand ourselves as part of a shared society, with a shared fate; she shows us that everyday places can be the spaces of liberation in which we can build the cities we need.
Principles of Argument Structure
Authors: Collins Chris
Published: February 2024

A new theory of argument structure, based on the syntactic operation Merge and presented through an in-depth analysis of properties of the English passive construction.

In Principles of Argument Structure, Chris Collins investigates principles of argument structure in minimalist syntax through an in-depth analysis of properties of the English passive construction. He formulates a new theory of argument structure based on the only structure-building operation in minimalist syntax, Merge, which puts together two syntactic objects to form a larger one. This new theory should give rise to detailed cross-linguistic work on the syntactic and semantic properties of implicit arguments.

Collins presents an update and defense of his influential 2005 theory of the passive, including a completely original theory of implicit arguments. He makes a direct empirical argument for the Theta-Criterion against various claims that it should be eliminated. He also discusses the conception of voice in syntactic theory, arguing that VoiceP does not introduce external arguments, a position otherwise widely accepted in the field. He shows how the ”smuggling” approach to the passive extends naturally to the dative alternation accounting for a number of striking c-command asymmetries. He compares syntactic and semantic approaches to argument structure, outlining conceptual problems with adopting formal semantics as the basis for a theory of argument structure.

The book will be of interest not only to syntacticians and semanticists, but also to typologists investigating the cross-linguistic properties of the passive, psycholinguists and computer scientists working on natural language understanding, and philosophers thinking about the issue of “implicit content.” It includes an appendix that provides common-sense guidelines for doing syntactic research using internet data.Chris Collins
Plasticity of gene expression in the nervous system by exposure to environmental odorants that inhibit HDACs
Authors: Haga-Yamanaka Sachiko , Nunez-Flores Rogelio , Scott Christi A , Perry Sarah , Chen Stephanie Turner , Pontrello Crystal , Nair Meera G , Ray Anandasankar
Published: February 2024

Eukaryotes respond to secreted metabolites from the microbiome. However, little is known about the effects of exposure to volatiles emitted by microbes or in the environment that we are exposed to over longer durations. Using Drosophila melanogaster, we evaluated a yeast-emitted volatile, diacetyl, found at high levels around fermenting fruits where they spend long periods of time. Exposure to the diacetyl molecules in headspace alters gene expression in the antenna. In vitro experiments demonstrated that diacetyl and structurally related volatiles inhibited conserved histone deacetylases (HDACs), increased histone-H3K9 acetylation in human cells, and caused changes in gene expression in both Drosophila and mice. Diacetyl crosses the blood–brain barrier and exposure caused modulation of gene expression in the mouse brain, therefore showing potential as a neuro-therapeutic. Using two separate disease models previously known to be responsive to HDAC inhibitors, we evaluated the physiological effects of volatile exposure. Diacetyl exposure halted proliferation of a neuroblastoma cell line in culture. Exposure to diacetyl vapors slowed progression of neurodegeneration in a Drosophila model for Huntington’s disease. These changes strongly suggest that certain volatiles in the surroundings can have profound effects on histone acetylation, gene expression, and physiology in animals.
Intra and interspecific diversity in a tropical plant clade alter herbivory and ecosystem resilience
Authors: Grele Ari J. , Massad Tara J. , Uckele Kathryn A. , Dyer Lee A. , Antonini Yasmine , Braga Laura , Forister Matthew L. , Sulca Lidia , Kato Massuo J. , Lopez Humberto G. , Nascimento Andre R. , Parchman Thomas L. , Simbaña Wilmer R. , Smilanich Angela M. , Stireman John O. , Tepe Eric J. , Walla Thomas R. , Richards Lora A.
Published: February 2024

Declines in biodiversity generated by anthropogenic stressors at both species and population levels can alter emergent processes instrumental to ecosystem function and resilience. As such, understanding the role of biodiversity in ecosystem function and its response to climate perturbation is increasingly important, especially in tropical systems where responses to changes in biodiversity are less predictable and more challenging to assess experimentally. Using large scale transplant experiments conducted at five neotropical sites, we documented the impacts of changes in intraspecific and interspecific plant richness in the genus
Piper
on insect herbivory, insect richness, and ecosystem resilience to perturbations in water availability. We found that reductions of both intraspecific and interspecific
Piper
diversity had measurable and site specific effects on herbivory, herbivorous insect richness, and plant mortality. The responses of these ecosystem-relevant processes to reduced intraspecific
Piper
richness were often similar in magnitude to the effects of reduced interspecific richness. Increased water availability reduced herbivory by 4.2% overall, and the response of herbivorous insect richness and herbivory to water availability were altered by both intra and interspecific richness in a site dependent manner. Our results underscore the role of intraspecific and interspecific richness as foundations of ecosystem function and the importance of community and location specific contingencies in controlling function in complex tropical systems.
Gut microbiota-derived gamma-aminobutyric acid from metformin treatment reduces hepatic ischemia/reperfusion injury through inhibiting ferroptosis
Authors: Wang Fangyan , Liu Xiujie , Huang Furong , Zhou Yan , Wang Xinyu , Song Zhengyang , Wang Sisi , Wang Xiaoting , Shi Dibang , Ruan Gaoyi , Ji Xiawei , Zhang Eryao , Tan Zenglin , Ye Yuqing , Wang Chuang , Zhu Jesse , Wang Wantie
Published: February 2024

Hepatic ischemia/reperfusion injury (HIRI) is a common and inevitable factor leading to poor prognosis in various liver diseases, making the outcomes of current treatments in clinic unsatisfactory. Metformin has been demonstrated to be beneficial to alleviate HIRI in recent studies, however, the underpinning mechanism remains unclear. In this study, we found metformin mitigates HIRI-induced ferroptosis through reshaped gut microbiota in mice, which was confirmed by the results of fecal microbiota transplantation (FMT) treatment but showed the elimination of the beneficial effects when gut bacteria were depleted using antibiotics. Detailedly, through 16S rRNA and metagenomic sequencing, we identified that the metformin-reshaped microbiota was characterized by the increase of gamma-aminobutyric acid (GABA) producing bacteria. This increase was further confirmed by the elevation of GABA synthesis key enzymes, glutamic acid decarboxylase (GAD) and putrescine aminotransferase (PAT), in gut microbes of metformin-treated mice and healthy volunteers. Furthermore, the benefit of GABA against HIRI-induced ferroptosis was demonstrated in GABA-treated mice. Collectively, our data indicate that metformin can mitigate HIRI-induced ferroptosis by reshaped gut microbiota, with GABA identified as a key metabolite.
Multi-day Neuron Tracking in High Density Electrophysiology Recordings using EMD
Authors: Yuan Augustine(Xiaoran) , Colonell Jennifer , Lebedeva Anna , Okun Michael , Charles Adam S. , Harris Timothy D.
Published: February 2024

Accurate tracking of the same neurons across multiple days is crucial for studying changes in neuronal activity during learning and adaptation. New advances in high density extracellular electrophysiology recording probes, such as Neuropixels, provide a promising avenue to accomplish this goal. Identifying the same neurons in multiple recordings is, however, complicated by non-rigid movement of the tissue relative to the recording sites (drift) and loss of signal from some neurons. Here we propose a neuron tracking method that can identify the same cells independent of firing statistics, which are used by most existing methods. Our method is based on between-day non-rigid alignment of spike sorted clusters. We verified the same cell identify using measured visual receptive fields. This method succeeds on datasets separated from one to 47 days, with an 84% average recovery rate.
Developmental conversion of thymocyte-attracting cells into self-antigen-displaying cells in embryonic thymus medulla epithelium
Authors: Ohigashi Izumi , White Andrea J. , Yang Mei-Ting , Fujimori Sayumi , Tanaka Yu , Jacques Alison , Kiyonari Hiroshi , Matsushita Yosuke , Turan Sevilay , Kelly Michael C. , Anderson Graham , Takahama Yousuke
Published: February 2024

Thymus medulla epithelium establishes immune self-tolerance and comprises diverse cellular subsets. Functionally relevant medullary thymic epithelial cells (mTECs) include a self-antigen-displaying subset that exhibits genome-wide promiscuous gene expression promoted by the nuclear protein Aire and that resembles a mosaic of extrathymic cells including mucosal tuft cells. An additional mTEC subset produces the chemokine CCL21, thereby attracting positively selected thymocytes from the cortex to the medulla. Both self-antigen-displaying and thymocyte-attracting mTEC subsets are essential for self-tolerance. Here we identify a developmental pathway by which mTECs gain their diversity in functionally distinct subsets. We show that CCL21-expressing mTECs arise early during thymus ontogeny. Fate-mapping analysis reveals that self-antigen-displaying mTECs, including Aire-expressing mTECs and thymic tuft cells, are derived from CCL21-expressing cells. The differentiation capability of CCL21-expressing embryonic mTECs is verified in reaggregate thymus experiments. These results indicate that CCL21-expressing embryonic mTECs carry a developmental potential to give rise to self-antigen-displaying mTECs, revealing that the sequential conversion of thymocyte-attracting subset into self-antigen-displaying subset serves to assemble functional diversity in the thymus medulla epithelium.
The evolution of transposable elements in Brachypodium distachyon is governed by purifying selection, while neutral and adaptive processes play a minor role
Authors: Horvath Robert , Minadakis Nikolaos , Bourgeois Yann , Roulin Anne C.
Published: February 2024

Understanding how plants adapt to changing environments and the potential contribution of transposable elements (TEs) to this process is a key question in evolutionary genomics. While TEs have recently been put forward as active players in the context of adaptation, few studies have thoroughly investigated their precise role in plant evolution. Here we used the wild Mediterranean grass
Brachypodium distachyon
as a model species to identify and quantify the forces acting on TEs during the adaptation of this species to various conditions, across its entire geographic range. Using sequencing data from more than 320 natural
B. distachyon
accessions and a suite of population genomics approaches, we reveal that putatively adaptive TE polymorphisms are rare in wild
B. distachyon
populations. After accounting for changes in past TE activity, we show that only a small proportion of TE polymorphisms evolved neutrally (< 10%), while the vast majority of them are under moderate purifying selection regardless of their distance to genes. TE polymorphisms should not be ignored when conducting evolutionary studies, as they can be linked to adaptation. However, our study clearly shows that while they have a large potential to cause phenotypic variation in
B. distachyon
, they are not favored during evolution and adaptation over other types of mutations (such as point mutations) in this species.
Hippocampal-occipital connectivity reflects autobiographical memory deficits in aphantasia
Authors: Monzel Merlin , Leelaarporn Pitshaporn , Lutz Teresa , Schultz Johannes , Brunheim Sascha , Reuter Martin , McCormick Cornelia
Published: February 2024

Aphantasia refers to reduced or absent visual imagery. While most of us can readily recall decade-old personal experiences (autobiographical memories, AM) with vivid mental images, there is a dearth of information about whether the loss of visual imagery in aphantasics affects their AM retrieval. The hippocampus is thought to be a crucial hub in a brain-wide network underlying AM. One important question is whether this network, especially the connectivity of the hippocampus, is altered in aphantasia. In the current study, we tested 14 congenital aphantasics and 16 demographically matched controls in an AM fMRI task to investigate how key brain regions (i.e. hippocampus and visual-perceptual cortices) interact with each other during AM re-experiencing. All participants were interviewed regarding their autobiographical memory to examine their episodic and semantic recall of specific events. Aphantasics reported more difficulties in recalling AM, were less confident about their memories, and described less internal and emotional details than controls. Neurally, aphantasics displayed decreased hippocampal and increased visual-perceptual cortex activation during AM retrieval compared to controls. In addition, controls showed strong negative functional connectivity between the hippocampus and the visual cortex during AM and resting-state functional connectivity between these two brain structures predicted better visualization skills. Our results indicate that visual mental imagery plays an important role in detail-rich vivid AM, and that this type of cognitive function is supported by the functional connection between the hippocampus and the visual-perceptual cortex.
Uncertainty-modulated prediction errors in cortical microcircuits
Authors: Wilmes Katharina A , Petrovici Mihai A , Sachidhanandam Shankar , Senn Walter
Published: February 2024

Understanding the variability of the environment is essential to function in everyday life. The brain must hence take uncertainty into account when updating its internal model of the world. The basis for updating the model are prediction errors that arise from a difference between the current model and new sensory experiences. Although prediction error neurons have been identified in layer 2/3 of diverse brain areas, how uncertainty modulates these errors and hence learning is, however, unclear. Here, we use a normative approach to derive how uncertainty should modulate prediction errors and postulate that layer 2/3 neurons represent uncertainty-modulated prediction errors (UPE). We further hypothesise that the layer 2/3 circuit calculates the UPE through the subtractive and divisive inhibition by different inhibitory cell types. By implementing the calculation of UPEs in a microcircuit model, we show that different cell types can compute the means and variances of the stimulus distribution. With local activity-dependent plasticity rules, these computations can be learned context-dependently, and allow the prediction of upcoming stimuli and their distribution. Finally, the mechanism enables an organism to optimise its learning strategy via adaptive learning rates.
The interplay of motor adaptation and groupitizing in numerosity perception: Insights from visual motion adaptation and proprioceptive motor adaptation
Authors: Yang Huanyu , Jia Liangzhi , Zhu Jun , Zhang Jian , Li Mengmeng , Li Chenli , Pan Yun
Published: February 2024

Groupitizing is a well-established strategy in numerosity perception that enhances speed and sensory precision. Building on the ATOM theory, Anobile proposed the sensorimotor numerosity system, which posits a strong link between number and action. Previous studies using motor adaptation technology have shown that high-frequency motor adaptation leads to underestimation of numerosity perception, while low-frequency adaptation leads to overestimation. However, the impact of motor adaptation on groupitizing, and whether visual motion adaptation produces similar effects, remain unclear. In this study, we investigate the persistence of the advantage of groupitizing after motor adaptation and explore the effects of visual motion adaptation. Surprisingly, our findings reveal that proprioceptive motor adaptation weakens the advantage of groupitizing, indicating a robust effect of motor adaptation even when groupitizing is employed. Moreover, we observe a bidirectional relationship, as groupitizing also weakens the adaptation effect. These results highlight the complex interplay between motor adaptation and groupitizing in numerosity perception. Furthermore, our study provides evidence that visual motion adaptation also has an adaptation effect, but does not fully replicate the effects of proprioceptive motor adaptation on groupitizing. In conclusion, our research underscores the importance of groupitizing as a valuable strategy in numerosity perception, and sheds light on the influence of motion adaptation on this strategy.
Sporting tournaments and changed birth rates 9 months later: a systematic review
Authors: Masukume Gwinyai , Grech Victor , Ryan Margaret
Published: February 2024

Introduction

Major sporting tournaments may be associated with increased birth rates 9 months afterwards, possibly due to celebratory sex. The influence of major sporting tournaments on birth patterns remains to be fully explored.

Methods

Studies that examined the relationship between such events and altered birth metrics (number of births and/or birth sex ratio (male/total live births)) 9(±1) months later were sought in PubMed and Scopus and reported via standard guidelines. Database searches were conducted up to 7 November 2022.

Results

Five events led to increased birth metrics 9(±1) months later and these included the Super Bowl, the 2009 UEFA Champions League, the 2010 FIFA World Cup, the 2016 UEFA Euros and the 2019 Rugby World Cup. Several la Liga soccer matches also had effects. With a few exceptions, major American football, Association football (soccer) and Rugby apex tournaments in Africa, North America, Asia and Europe were associated with increases in the number of babies born and/or in the birth sex ratio 9(±1) months following notable team wins and/or hosting the tournament. Furthermore, unexpected losses by teams from a premier soccer league were associated with a decline in births 9 months on.

Conclusions

This systematic review establishes that major sporting tournaments have a notable impact on birth patterns, influencing both birth rates and sex ratios. Emotional intensification during these events likely triggers hormonal shifts, driving changes in sexual activity and subsequently shaping birth rates, often positively, about 9 months later. The context is crucial, especially when a region/country hosts a major single-sport tournament or participates for the first time, as population excitement is likely to be at its peak. These findings hold significance for healthcare planning and highlight the role of societal events in shaping demographic trends.

PROSPERO registration

CRD42022382971.
Mother’s Perception on Childbirth: Cesarean Section vs Normal Birth
Authors: Malahayati Inke , Zuraidah
Published: February 2024

Background: Cesarean section has increased from year to year. The 2018 Indonesia Basic Health Research found that the percentage of cesarean deliveries was 17.6% of 78.736 deliveries. It has almost twice from the 2013 Indonesia Basic Health Research of 9.8%. Various reasons were given by mothers for choosing cesarean section.

Aims: To explore differences in mothers' perceptions of cesarean section and normal birth.  Here clearly write the aims of this study.

Study Design: This study used a comparative study.

Place and Duration of Study: This study was conducted in Simalungun Regency (North Sumatera, Indonesia) between July and September 2022.

Methodology: We conducted on 106 women after 24 hours of labor (normal labor and cesarean section). Sampling was done by consecutive sampling. Data were collected using the Perception of Birth Scale/PBS questionnaire (29 questions) with a Likert scale of 1-5 and the Labor Agentry Scale/LAS (10 questions) with a Likert scale of 1-7 that had been translated and validated. Statistical test using Mann-Whitney U.

Results: The mean PBS scores in the normal labor vs cesarean section group were 105.68 ± 10.95 and 109.09 ± 8.79 (p=0.026). The mean LAS score in the normal labor vs cesarean section group was 34.57 ± 5.27 vs 31.51 ± 4.37 (P value 0.000).

Conclusion: Mothers who gave birth by cesarean section had a positive perception. Mothers who gave birth normally had high birth control. Education and information about the risks of the cesarean section should be promoted and mothers are supported to give birth naturally.
Analyzing the Physical Characteristics of Garlic for Agricultural and Machinery Applications
Authors: Sonwani Suryakant , Victor V. M. , Naik R. K.
Published: February 2024

Garlic, a globally cherished spice from the Allium Sativum L. family, holds immense importance in Indian agriculture as the second-largest producer worldwide. With India contributing 10.4% to the global garlic production, totaling 3.27 million metric tons in 2022, the physical properties of garlic become integral in engineering design. This research navigates through experiments on garlic clove bulk density, considering moisture levels, and explores the mechanical aspects affecting agricultural and machinery applications. Moisture content considerations for storage, odor/flavor impact, and even the friction coefficient concerning bulb size underscore the complexity of garlic's engineering dynamics. By unraveling these properties, this study aims to fuel advancements in cultivation practices, machinery design, and processing technologies, enhancing efficiency and product quality in the agricultural and food engineering sectors.
Combining Ability Studies for Maturity, Growth, Yield and Quality Traits in Tomato (Solanum lycopersicum L.)
Authors: Farwah Syeda , Afroza Baseerat , Dar Zahoor A. , Nazir Gazala , Masoodi Ummyiah H. , Nabi Ambreen , Shamma Rani
Published: February 2024

A study was conducted at Vegetable Research Farm, Vegetable Science Division, SKUAST- Kashmir, Shalimar, India to determine the general and specific combining abilities for maturity, growth, yield and quality traits in tomato by crossing 12 parents in a diallel Method II and Model I of Griffing mating design during Kharif season 2020. The F1 progenies of the sixty-six crosses (excluding reciprocals) were evaluated along with the twelve parents in Randomized Block Design during Kharif season 2021 at three locations. The observations were recorded on eighteen diverse traits. The analysis of variance for general combining ability (GCA) and specific combining ability (SCA) revealed significant mean squares due to GCA and SCA for all the traits under consideration. The mean squares due to GCA × environments and SCA × environments were found significant for most of the characters. None of the parents possessed significant and desirable GCA for all the traits. Different parents were found to reveal desirable general combining ability for different traits. Similarly, none of the crosses possessed significant and desirable specific combining ability for all the traits. However, different crosses were found to reveal desirable SCA for different traits.
Development and Characterization of Nano-Chitosan-Polyvinyl Alcohol-Glycerol -Chlorhexidine Films for Wound Healing Applications
Authors: Rosemol Jacob M.  , Amruth P.  , Paul Preethy Treesa , Joy Jean Mary , Visnuvinayagam S.  , Dara Pavan Kumar , Anandan R. , Mathew Suseela
Published: February 2024

The process of wound healing is intricate and dynamic, requiring advanced medical care for a speedy recovery. Currently available semi-permeable wound dressings fall short in efficiently absorbing excess wound exudates to facilitate moist wound care, a crucial factor for promoting effective wound healing. Additionally, efforts have been made to enhance the antibacterial properties of wound dressings by incorporating antimicrobials into films. In this study, films were development using nanochitosan-polyvinyl alcohol-glycerol-chlorhexidine (NC-PVA-GLY-CLX) for applications in wound healing. The dressings were subjected to various characterizations, including UV-Visible spectrometry, Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, Thermogravimetric analysis, and X‑ray diffraction pattern. Furthermore, the resulting film dressings underwent evaluation for their bactericidal properties. The findings indicated that the incorporation of chlorhexidine into the films has positively influenced the fluid holding capacity and the active period of the dressing, creating a favourable environment for effective wound healing.
Influence of pH of Phosphating Bath on the Zinc Phosphate Coating on AZ91D Magnesium Alloy
Authors: Li G. Y. , Lian J. S. , Niu L. Y. , Jiang Z. H.
Published: February 2006

Suitable pH of the phosphating bath is crucial to restrain resolving rate of magnesium and obtain high quality phosphate coatings because of the high activity of magnesium. In this investigation a compact zinc phosphate coatings on AZ91D were successfully obtained from the phosphating bath with pH=2.15∼2.5. This figure indicated that the slab‐like phosphate crystals were entirely covered the substrate when the pH of the phosphating bath is 2.5.
Effect of Heat Treatment and Thermochemical Treatment on Linear Recovery Property of TiNi Shape Memory Alloy
Authors: Wang G. , Yang G. , Huang Y. , Wang J.
Published: February 2006

A new concept of linear recovery behavior in TiNi shape memory alloy (SMA) is proposed in this article. Effects of heat treatment and thermochemical treatment including “Ceriuming” and “Samariuming” on the linear recovery property of TiNi SMA were investigated through measuring the thermal reversion curves. The results indicates that the linear recovery properties can be modified by both heat treatment and thermochemical treatment.
Gigahertz and Nanotubes – Perspectives for Innovations with Novel Industrial Microwave Processing Technology
Authors: Feher L. , Thumm M. , Drechsler K.
Published: February 2006

A novel industrial microwave system HEPHAISTOS‐CA2 (High Electromagnetic Power Heating Automated Injected Structures Oven System) for curing of carbon fibre reinforced plastics is being developed at Forschungszentrum Karlsruhe (FZK). The system is based on the HEPHAISTOS‐CA1 prototype system at FZK which has been evaluated for the application in composite manufacturing together with EADS Corporate Research Centre and the Institute of Aircraft Design (University of Stuttgart). The system, which is in duty since the end of 2005 integrates advantageously the basic processing steps as tooling, tempering of the resin and lay up, the impregnation of the fibres, pre‐forming techniques as well as finally the process curing of the composite structures.
Correlating Interfacial Moisture Content and Adhesive Fracture Energy of Polymer Coatings on Different Surfaces
Authors: O'Brien E. P. , White C. C. , Vogt B. D.
Published: February 2006

The adhesion of polymer film of PMMA to different surfaces was measured using the shaft‐loaded blister test. The exposure of the films to saturated water vapor generally leads to a decrease in adhesive strength. The adhesion loss was directly related to the moisture accumulation at the polymer/substrate interface as measured using neutron reflectivity.
Influence of the Surface Treatment on the Deposition of Platinum Nanoparticles on the Carbon Nanotubes
Authors: Xu C. , Chen J. , Cui Y. , Han Q. , Choo H. , Liaw P. K. , Wu D.
Published: February 2006

The influence of the pretreatment of carbon nanotubes (CNTs) on the deposition of Pt‐n noparticles is investigated. The results show that refluxing CNTs by the mixture solution of sulfuric and nitric acids, or immersing them in the H2O2solution are effective ways for depositing Pt‐nanoparticles on the CNTs. The hybrid process yields the best results and obtained the Pt‐nanoparticles with a size of about 3 nm on the CNTs surface.
Increasing the Strength/Toughness Combination of High Volume Fraction Particulate Metal Matrix Composites using an Al‐Ag Matrix Alloy
Authors: Miserez A. , Müller R. , Mortensen A.
Published: February 2006

Ceramic reinforced metals, despite superior properties such as specific stiffness, are often considered as too brittle for structural applications. We show that despite a high ceramic particle content (60 vol.%), aluminium matrix composites can be made to exhibit a fracture toughness matching that of unreinforced aluminium alloys, provided critical microstructural parameters are controlled. We here use an unconventional Al‐Ag matrix to simultaneously increase the strength and the toughness of this class of composite.
Formation of Nanostructured Titania: Effect of Thickness on Oxidation Kinetics of Titanium Thin Films in Aqueous Hydrogen Peroxide
Authors: DeRosa D. M. , Zuruzi A. S. , MacDonald N. C.
Published: February 2006

The oxidation kinetics of Ti films in aqueous hydrogen peroxide was investigated. Oxidation of Ti films is dependent on both film thickness and average grain size. Films of thickness 50 nm or less exhibit Stage I oxidation while thicker films exhibit both Stages I and II. The difference in oxidation rates and dependencies on grain size observed in these two stages are attributed to different mechanisms controlling oxide growth.
Pressure Free Fabrication of 3D Microcomponents Using Al Powder
Authors: Kim J.‐S. , Jiang K. , Chang I.
Published: February 2006

This paper presents a new fabrication process of producing 3D microparts using Al microparticle powder. The process does not need high compression pressure and the powder mixture is loosely filled in soft moulds. High density components have been produced through this process. The proposed technology is developed in combination of micro metal injection moulding (μMIM), micro powder injection moulding (μPIM), powder sintering technology and MEMS technology together.
Platinum Ceramic Composites as new Electrode Materials: Fabrication, Sintering, Microstructures and Properties
Authors: Rager J. , Nagel A. , Schwenger M. , Flaig A. , Schneider G. , Mücklich F.
Published: February 2006

The economical application of precious metals as electrode materials is an important economic and ecological task. Different platinum composites with 14 vol.% ceramic dispersoids were fabricated. The sintering behaviour and microstructure development was studied in the temperature range between 1000°C and 1760°C. Significant differences were found with respect to the sintering activity and the particle size distribution. Spark erosion tests revealed that the erosion resistance of platinum is degraded by the addition of oxide particles. A new model is proposed to explain the observed erosion behaviour.
Comparison of Shape Memory Metals and Polymers
Authors: Hornbogen E.
Published: February 2006

Both, metals and polymers can show the one‐way shape memory effect or rubber‐like elasticity. The origin of these effects in the two types of materials is discussed. It is shown that there is an analogy between the high temperature phases β: crystalline austenite in metals and random coils in polymers. There are differences in the low temperature phases α: a domain structure is typical for metallic martensite, and stretched chains for polymers. Prerequisite for memory and superelastic effects is a complete structural reversibility during a β – α transformation cycle.
Carbon Nanotubes Strengthened Nanophase WC‐Co Hard Alloys
Authors: Tan G.‐L. , Wu X.‐J. , Li Z.‐Q.
Published: February 2006

A novel approach employing C2H2 instead of CO as carburization agent has been applied to fabricate nanophase WC‐Co composite alloys being strengthened by carbon nanotubes and nanorods, which were formed in‐situ during C2H2 carburization process. The sintered composite alloys show exceptionally high microhardness. Carbon nanotubes are supposed to play roles on strengthening the matrix and prohibiting growth of WC grains, thus greatly improving the mechanical properties of the matrix.
Microstructural Bases for the Superior Densification of Gels doped with Alumina Nanoseeds
Authors: Tartaj J. , Tartaj P.
Published: February 2006

The densification behavior of alumina gels has been studied. We have found that in addition to the effect of volume transformed, the thermal history of gels plays an important role in their densification process. Particularly, prior to the θ‐ to α transformation, the nanoseeded gels preserve a close packed and evenly distributed porous structure that helps to achieve full density at lower temperatures.
Surface and Sub‐Surface Quality of Steel after EDM
Authors: Bleys P. , Kruth J.‐P. , Lauwers B. , Schacht B. , Balasubramanian V. , Froyen L. , Van Humbeeck J.
Published: February 2006

This paper deals with the influence of electrical discharge machining (EDM) on surface and sub‐surface quality in the manufacturing of mould and tool steel. The thermal nature of material removal by EDM yields a thermally affected zone at the surface of the manufactured part. This zone consists of a molten and resolidified layer, and a heat affected zone, showing properties that differ considerably from the base material. Based on experimental investigations with three types of EDM processes (sinking EDM, wire EDM and milling EDM), the influence of process parameters on surface and sub‐surface properties is discussed. These include surface roughness, sub‐surface micro‐structure and composition, micro‐hardness and residual stresses. Attention goes to the dangers of surface degradation, yet also to the opportunities to use the EDM process for surface improvement.
Creation of Porous Ceria by Sublimation of Tin Dioxide during Sintering
Authors: Liu Y. , Liu M.
Published: February 2006

Highly porous CeO2 was prepared by natural sublimation of SnO2 during firing of a CeO2‐SnO2 nanocomposite powder synthesized using combustion CVD. Unlike the conventional strategies, the new method requires neither time consuming chemical leaching nor following‐up gas reduction procedures. This approach is attractive to fabrication of porous structures for solid oxide fuel cells, gas separation, and catalysis since no chemical leaching or gas reduction is involved.
Biomimetic Formation of Hydroxyapatite/collagen Matrix Composite
Authors: Wang Y. , Yang C. , Chen X. , Zhao N.
Published: February 2006

A composite of collagen (COL) and hydroxyapatite(HA) was prepared using a biomimetic approach, which performs a direct nucleation of HA on self‐ assembled collagen matrix. This research may be helpful to understand the possible mechanisms for collagen‐mediated mineralization in general and the COL/HCA composite can be considered a new particularly attractive material for human bone tissue implantation.
Cover Picture: Platinum Ceramic Composites as new Electrode Materials: Fabrication, Sintering, Microstructures and Properties (Adv. Eng. Mater. 1‐2/2006)
Authors: Rager J. , Nagel A. , Schwenger M. , Flaig A. , Schneider G. , Mücklich F.
Published: February 2006

The cover shows the the microstructure of a Pt/MgO composite which could be fully densified at sintering temperatures above 1700°C. More about platinum ceramic composites and their properties can be found in the article by J. Rager on page 81.
Ionic Liquids as Solvents for Catalyzed Oxidations of Organic Compounds
Authors: Muzart Jacques
Published: February 2006

This review summarizes the oxidation methods of organic compounds carried out in the presence of a catalyst using ionic liquids or molten ammonium salts as solvents. From an ecological point of view, these procedures are particularly interesting when the catalyst is efficiently immobilized in the solvent, thus leading to a reusable system.
Hafnium Chloride Tetrahydrofuran Complex‐Catalyzed Diels–Alder Cycloadditions of 3‐Ethoxycarbonylcoumarins with 1,3‐Dienes under Solvent‐Free Conditions
Authors: Fringuelli Francesco , Girotti Rugiada , Pizzo Ferdinando , Zunino Ennio , Vaccaro Luigi
Published: February 2006

Hafnium chloride tetrahydrofuran complex (HfCl4⋅2 THF) is an efficient catalyst for the Diels–Alder cycloadditions of 3‐ethoxycarbonylcoumarins 1a–c and 1,3‐butadienes 2x–z under solvent‐free conditions furnishing the corresponding cycloadducts in excellent yields. This salt is an air stable Lewis acid and therefore the reactions can be performed in air atmosphere making the procedure simple to be carried out.
Design and Assembly of Virtual Homogeneous Catalyst Libraries –Towards in silico Catalyst Optimisation
Authors: Hageman Jos A. , Westerhuis Johan A. , Frühauf Hans‐Werner , Rothenberg Gadi
Published: February 2006

An alternative top‐down concept for searching for homogeneous catalysts is introduced. In this approach, three multi‐dimensional spaces are considered. These represent the catalysts, the descriptor values (e.g., cone angle, lipophilicity indices), and the figures of merit (e.g., turnover frequency, enantiomeric excess, or product selectivity), respectively. By generating and connecting these spaces, it is possible to screen virtual catalyst libraries and indicate regions in the catalyst space where good catalysts are likely to be found. The generation of the catalyst space from simple building blocks is presented and the application of this approach is demonstrated for two cases: predicting the bite angle in a library of 600 ligand‐Rh complexes, and predicting the linear : branched aldehyde product ratio that these 600 catalysts would give in the hydroformylation of 1‐octene. In the latter case, the model is first trained on a set of 39 octene hydroformylation reactions. The limitations and applications of this concept are discussed.
Access to Stereodefined Trisubstituted Alkenes via Rhodium‐Catalyzed 1,4‐Addition of Potassium Trifluoro(organo)‐ borates to Baylis–Hillman Adducts
Authors: Navarre Laure , Darses Sylvain , Genet Jean‐Pierre
Published: February 2006

In the presence of a rhodium catalyst, unactivated Baylis–Hillman adducts reacted regioselectively with potassium trifluoro(organo)borates to afford stereodefined trisubstituted alkenes with good yields. This highly efficient reaction (aerobic conditions, low temperature, absence of added phosphane ligand) is believed to proceed via a 1,4‐addition/β‐hydroxy elimination mechanism.
Gold‐Catalysed Direct Couplings of Indoles and Pyrroles with 1,3‐Dicarbonyl Compounds
Authors: Arcadi Antonio , Alfonsi Maria , Bianchi Gabriele , D'Anniballe Gaetano , Marinelli Fabio
Published: February 2006

The gold‐catalysed direct couplings of indoles 1 and pyrroles 5 with 1,3‐dicarbonyls 2 is described. This new method for CC bond formation allows high functional group tolerance, regioselectivity, and scope under relatively mild conditions. Moreover, the 3‐alkenylindoles 3 can be readily available through gold‐catalysed sequential cyclization/alkenylation reaction of 2‐alkynylanilines derivatives 4 with 1,3‐dicarbonyls 2.
Bis(3,5‐dimethylphenyl)‐(S)‐pyrrolidin‐2‐ylmethanol: an Improved Organocatalyst for the Asymmetric Epoxidation of α,β‐Enones
Authors: Lattanzi Alessandra
Published: February 2006

The asymmetric epoxidation of α,β‐enones by the readily available bis(3,5‐dimethylphenyl)‐(S)‐pyrrolidin‐2‐ylmethanol and tert‐butyl hydroperoxide (TBHP) is described. Stereoelectronic substitution on the aryl moiety of diaryl‐2‐pyrrolidinemethanols was found to significantly affect the efficiency with respect to the previously reported (S)‐diphenyl‐2‐pyrrolidinemethanol. Improved reactivity and enantioselectivity were achieved with bis(3,5‐dimethylphenyl)‐(S)‐pyrrolidin‐2‐ylmethanol at reduced catalyst loading (20 mol %) with ees up to 94% for chalcone epoxides under mild reaction conditions, whereas (S)‐diphenyl‐2‐pyrrolidinemethanol afforded a maximum ee of 80%. Interestingly, the methodology is applicable to the epoxidation of more challenging aliphatic or enolizable enones with good control of the asymmetric induction (up to 87% ee).
Highly Selective Preparation of Allenic and Homopropargylic Hydrazides through Regiospecific Addition of Propargyltrichlorosilane and Allenyltrichlorosilane to Various Types of N‐Acylhydrazones
Authors: Schneider Uwe , Sugiura Masaharu , Kobayashi Shū
Published: February 2006

The highly selective preparation of various types of allenic and homopropargylic hydrazides through regiospecific allenylation and propargylation of the corresponding N‐acylhydrazones is reported. These carbon‐carbon bond‐forming reactions employing in situ prepared propargyl‐ and allenyltrichlorosilanes proceed smoothly in N,N‐dimethylformamide (DMF) without any metal catalysis (neutral Lewis base activation of nucleophiles). The use of Hünig's base as an additive is beneficial in terms of chemical yields.
Aerobic Oxidation of Glucose with Gold Catalyst: Hydrogen Peroxide as Intermediate and Reagent
Authors: Comotti Massimiliano , Della Pina Cristina , Falletta Ermelinda , Rossi Michele
Published: February 2006

Careful analytical determinations show that the gold‐catalysed aerobic oxidation of glucose occurs through a two‐electrons mechanism leading to gluconate and hydrogen peroxide. This latter decomposes before reaching the critical concentration for competing with O2 in glucose oxidation. A mechanism of glucose oxidation on gold nanoparticles is presented.
[CpRu(IV)(π‐C3H5)(2‐quinolinecarboxylato)]PF6 Complex: A Robust Catalyst for the Cleavage and Formation of Allyl Ethers
Authors: Tanaka Shinji , Saburi Hajime , Kitamura Masato
Published: February 2006

A facile and efficient method for the quantitative synthesis of [CpRu(IV)(π‐C3H5)(2‐quinolinecarboxylato)]PF6 from [CpRu(CH3CN)3]PF6, 2‐quinolinecarboxylic acid, and 2‐propen‐1‐ol has been established. The cationic Ru(IV) complex is air‐ and moisture‐stable, and can be stored in a vial for at least six months. This complex realizes a simple and easy operation for both the deallylation of allyl ethers in methanol and the dehydrative allylation of alcohols. Furthermore, with removal of the volatile allyl methyl ether co‐product from the reaction system, the robust catalyst can attain a turnover of 10000 cycles of allyl ether cleavage.
Heptakis(2,3‐di‐O‐methyl‐6‐O‐sulfopropyl)‐β‐cyclodextrin: A Genuine Supramolecular Carrier for Aqueous Organometallic Catalysis
Authors: Kirschner D. , Green T. , Hapiot F. , Tilloy S. , Leclercq L. , Bricout H. , Monflier E.
Published: February 2006

The behavior of heptakis(2,3‐di‐O‐methyl‐6‐O‐sulfopropyl)‐β‐cyclodextrin as inverse phase transfer catalyst in biphasic Tsuji–Trost and hydroformylation reactions has been investigated. In terms of activity, this methylated sulfopropyl ether β‐cyclodextrin is much more efficient than the randomly methylated β‐cyclodextrin, which was the most active cyclodextrin known to date. From a selectivity point of view, the intrinsic properties of the catalytic system are fully preserved in the presence of this cyclodextrin as the chemo‐ or regioselectivity was found to be identical to that observed without a mass transfer promoter in the hydroformylation reaction. The efficiency of this cyclodextrin was attributed to its high surface activity and to the absence of interactions with the catalytically active species and the water‐soluble phosphane used to dissolve the organometallic catalyst in the aqueous phase.
Highly Regioselective DABCO‐Catalyzed Nucleophilic Aromatic Substitution (SNAr) Reaction of Methyl 2,6‐Dichloronicotinate with Phenols
Authors: Shi Yao‐Jun , Humphrey Guy , Maligres Peter E. , Reamer Robert A. , Williams J. Michael
Published: February 2006

Exclusive formation of 6‐aryloxy ethers 9 from an SNAr reaction of methyl 2,6‐dichloronicotinate (2) with phenols 7 catalyzed by 1,4‐diazabicyclo[2.2.2]octane (DABCO) in the presence of stoichiometric triethylamine is described. The reaction proceeds via the regioselective formation of an unprecedented DABCO‐pyridine adduct 10a.
Adhesion force between fine particles with controlled surface properties
Authors: Quintanilla M. A. S. , Valverde J. M. , Castellanos A.
Published: February 2006

The adhesion force between previously consolidated polymer particles is affected by the use of additives that modify relevant surface parameters, such as the contact hardness and size of asperities at contact. Both the size of silica nanoparticles uniformly coating the particle surfaces, and their surface coverage have been investigated. The effects of the presence of other additives, such as wax and cross‐linking polymer were tested. The experimental results are compared with predictions from theoretical models. Our measurements are shown to be in semi‐quantitative agreement with the theoretical expectations built on the hypothesis of plastic flow of interparticle contacts. Moreover, the results indicate that the aggregation of individual particles in the fluidlike regime must play a relevant role in how bulk stresses distribute among interparticle contacts when the powder transits to the solid state. This work highlights the need of considering particle aggregation and contact plasticity as central features, mostly obviated so far, to deal with real problems on cohesive powders. © 2006 American Institute of Chemical Engineers AIChE J, 2006
Cognitive‐behavioral profiles of females with the fragile X mutation
Authors: Fisch Gene S.
Published: February 2006

The fragile X (FRAXA) mutation is typically manifested as either a full mutation (FM) or premutation (PM), and is often associated with some form of learning impairment. The study by Lachiewicz et al. in this issue suggests that females with the FM or PM exhibit a specific profile of strengths in verbal abilities and significant weaknesses in quantitative skills. We examined 17 females with either the FM or PM using a standard cognitive‐behavioral battery consisting of the Stanford–Binet (4th Edition; SBFE) and the Vineland Adaptive Behavior Scale (VABS). Although we found the expected differences in composite IQ scores and adaptive behavior composite scores (DQ) between FM and PM females, we found no significant differences between verbal and quantitative reasoning in either group. © 2006 Wiley‐Liss, Inc.