bluuebunny/crossref_metadata_2025 huggingface dataset:
Word Learning by Preschoolers With SLI: Effect of Phonotactic Probability and Object Familiarity
Authors: Gray Shelley , Brinkley Shara , Svetina Dubravka
Published: March 2012

Purpose

In this study, the authors investigated whether previous findings of a low phonotactic probability/unfamiliar object word-learning advantage in preschoolers could be replicated, whether this advantage would be apparent at different “stages” of word learning, and whether findings would differ for preschoolers with specific language impairment (SLI) and typical development (TD).

Method

Participants included 114 children: 40 with SLI, 39 with TD matched for age and gender, and 35 with TD matched for expressive vocabulary and gender. Comprehension and production were assessed during word learning and at post-test for words that varied in phonotactic probability and object familiarity.

Results

Across groups, comprehension performance increased significantly from Day 1 to Day 2 and from Day 2 to Day 3, but there was no significant word/object type effect. Production performance increased significantly from Day 1 to Day 2, from Day 2 to Day 3, and from Day 3 to Day 4 for all groups, and there was a clear low phonotactic probability/unfamiliar object advantage during word learning but not at post-test.

Conclusion

Results help to establish that preschoolers with TD and SLI show a low phonotactic probability/unfamiliar object production advantage during word learning that is not restricted to the first few exposures to words, but continues over time. This study illustrates how the interaction of phonological characteristics in nascent and extant words can affect word learning.
The Effect of Technology and Testing Environment on Speech Perception Using Telehealth With Cochlear Implant Recipients
Authors: Goehring Jenny L. , Hughes Michelle L. , Baudhuin Jacquelyn L. , Valente Daniel L. , McCreery Ryan W. , Diaz Gina R. , Sanford Todd , Harpster Roger
Published: March 2012

Purpose

In this study, the authors evaluated the effect of remote system and acoustic environment on speech perception via telehealth with cochlear implant recipients.

Method

Speech perception was measured in quiet and in noise. Systems evaluated were Polycom visual concert (PVC) and a hybrid presentation system (HPS). Each system was evaluated in a sound-treated booth and in a quiet office.

Results

For speech in quiet, there was a significant effect of environment, with better performance in the sound-treated booth than in the office; there was no effect of system (PVC or HPS). Speech in noise revealed a significant interaction between environment and system. Subjects' performance was poorer for PVC in the office, whereas performance in the sound-treated booth was not significantly different for the two systems. Results from the current study were compared to results for the same group of subjects from an earlier study; these results suggested that poorer performance at remote sites in the previous study was primarily due to environment, not system.

Conclusions

Speech perception was best when evaluated in a sound-treated booth. HPS was superior for speech in noise in a reverberant environment. Future research should focus on modifications to non-sound-treated environments for telehealth service delivery in rural areas.
Investigation of spin and orbital moments of L1 FePtRh thin films
Authors: Xu D. B. , Sun C. J. , Chen J. S. , Han S.-W. , Heald S. M. , Rosenberg R. A. , Chow G. M.
Published: March 2012

Fe50Pt50−xRhx films have attracted much interest recently due to their potential usage in heat assisted magnetic recording media and the ferromagnetic (FM) to antiferromagnetic (AFM) transition as Rh concentration is increased. In this study, we present an investigation of the spin moment (ms) and orbital moment (ml) of Fe in Fe50Pt50−xRhx films using x-ray magnetic circular dichroism. The measurements were made in the soft x-ray region along the film normal, which corresponds to the easy axis of the (001) textured L10 FePt with uni-axial magnetic anisotropy. They show that the magnetic moment of Fe mainly contributes to the whole magnetization of the films. The decrease of ml with Rh doping concentration implies a decrease of magneto-crystalline anisotropy, whereas the significant decrease of ms is consistent with the FM to AFM transition at above 15 at. % of Rh.
A theoretical and experimental study of magnetism in Gd2In
Authors: Singh Vijay , Bhattacharyya Amitava , Majumdar Subham , Dasgupta Indra
Published: March 2012

We present detailed theoretical calculations and careful experiments to elucidate the magnetic properties of Gd2In. Our calculations suggest that Gd2In is a rather unique system where both localized 4f electrons as well as itinerant 5d electrons all originating from Gd are responsible for its novel magnetic properties with hardly any role of In s, p electrons. A careful analysis of the magnetization and magnetoresistance data as a function of field revealed that the magnetic behavior of Gd2In may be divided into three distinct regions. We argue with the aid of first principles electronic structure calculations that these three regions originate due to the different response of the localized 4f and itinerant 5d electrons of Gd upon application of the magnetic field. We show that in addition to the Gd 4f electrons, the Gd 5d electrons are also important for the metamagnetic behavior of Gd2In. These results establish the important role of Gd 5d electrons in the magnetic properties of Gd2In that so far only remained a speculation.
Fluid transport in nanochannels induced by temperature gradients
Authors: Liu Chong , Lv Ya , Li Zhigang
Published: March 2012

We investigate the mechanisms of fluid transport driven by temperature gradients in nanochannels through molecular dynamics simulations. It is found that the fluid-wall interaction is critical in determining the flow direction. In channels of very low surface energy, where the fluid-wall binding energy ɛfw is small, the fluid moves from high to low temperature and the flow is induced by a potential ratchet near the wall. In high surface energy channels, however, the fluid is pumped from low to high temperature and the pressure drop caused by the temperature gradient is the major driving force. In addition, as the fluid-wall interaction is strengthened, the flow flux assumes a maximum, where ɛfw is close to the lower temperature TL of the channel and ɛfw/kTL ≈ 1 is roughly satisfied.
Enhancing mechanical energy harvesting with dynamics escaped from potential well
Authors: Ma T. , Zhang H.
Published: March 2012

The potential of utilizing the dynamics outside the potential well of a device for harvesting energy from vibrations is investigated. A pendulum-type system subjected to parametrical excitation is used to demonstrate the concept. When the dynamics of the device is outside the potential well and stays in stable orbits of period-one rotations, the harvested energy is proportional to the energy level of the orbit. It is neither dependent on the natural frequency of the device nor on the intensity of the excitation. For low-level vibrations, the effectiveness of the proposed method is limited in relatively low frequencies.
The ‘Double Face' Illusion
Authors: Hancock Peter J B , Foster Catherine
Published: March 2012

We report three experiments intended to characterise aspects of the ‘double face’ illusion, formed by replicating the eyes and mouth below the originals. Such doubled faces are disturbing to look at. We find there are wide individual differences in the ability to detect that a face has been doubled when presented briefly and masked. These differences appear to relate to perceptual speed, since they correlate with the ability to identify a briefly presented famous face. Doubling has a significant effect on identification, though much less than inversion. In a reaction-time study, participants are faster to decide that a face has been doubled as it is rotated away from upright. The final study shows that normal and doubled faces do not pop out from each other, but reveals a processing overhead of 40–60 ms per doubled face. We offer some speculations as to the cause of the perceptual effects.
Perceptual Filling-in of Negative Coloured Afterimages
Authors: Hamburger Kai , Geremek Adam , Spillmann Lothar
Published: March 2012

Filling-in of brightness, colour, and texture refers to the perceptual spreading of surround features onto the target area. This phenomenon has been extensively investigated in real images. Here, we study colour spreading in afterimages of disk-ring patterns, using a variety of colour combinations. We show that colour filling-in and filling-out in afterimages follow rules different from those found for real images, suggesting that the brain treats afterimages as genuine ‘stimuli’.
Water and thermal regimes for field pea in Australia and their implications for breeding
Authors: Sadras V. O. , Lake L. , Chenu K. , McMurray L. S. , Leonforte A.
Published: March 2012

There is a large gap between the refined approaches to characterise genotypes and the common use of location and season as a coarse surrogate for environmental characterisation of breeding trials. As a framework for breeding, the aim of this paper is quantifying the spatial and temporal patterns of thermal and water stress for field pea in Australia. We compiled a dataset for yield of the cv. Kaspa measured in 185 environments, and investigated the associations between yield and seasonal patterns of actual temperature and modelled water stress. Correlations between yield and temperature indicated two distinct stages. In the first stage, during crop establishment and canopy expansion before flowering, yield was positively associated with minimum temperature. Mean minimum temperature below ~7°C suggests that crops were under suboptimal temperature for both canopy expansion and radiation-use efficiency during a significant part of this early growth period. In the second stage, during critical reproductive phases, grain yield was negatively associated with maximum temperature over 25°C. Correlations between yield and modelled water supply/demand ratio showed a consistent pattern with three phases: no correlation at early stages of the growth cycle, a progressive increase in the association that peaked as the crop approached the flowering window, and a progressive decline at later reproductive stages. Using long-term weather records (1957–2010) and modelled water stress for 104 locations, we identified three major patterns of water deficit nation wide. Environment type 1 (ET1) represents the most favourable condition, with no stress during most of the pre-flowering phase and gradual development of mild stress after flowering. Type 2 is characterised by increasing water deficit between 400 degree-days before flowering and 200 degree-days after flowering and rainfall that relieves stress late in the season. Type 3 represents the more stressful condition with increasing water deficit between 400 degree-days before flowering and maturity. Across Australia, the frequency of occurrence was 24% for ET1, 32% for ET2 and 43% for ET3, highlighting the dominance of the most stressful condition. Actual yield averaged 2.2 t/ha for ET1, 1.9 t/ha for ET2 and 1.4 t/ha for ET3, and the frequency of each pattern varied substantially among locations. Shifting from a nominal (i.e. location and season) to a quantitative (i.e. stress type) characterisation of environments could help improving breeding efficiency of field pea in Australia.
Selective esterase–ester pair for targeting small molecules with cellular specificity
Authors: Tian Lin , Yang Yunlei , Wysocki Laura M. , Arnold Alma C. , Hu Amy , Ravichandran Balaji , Sternson Scott M. , Looger Loren L. , Lavis Luke D.
Published: March 2012

Small molecules are important tools to measure and modulate intracellular signaling pathways. A longstanding limitation for using chemical compounds in complex tissues has been the inability to target bioactive small molecules to a specific cell class. Here, we describe a generalizable esterase–ester pair capable of targeted delivery of small molecules to living cells and tissue with cellular specificity. We used fluorogenic molecules to rapidly identify a small ester masking motif that is stable to endogenous esterases, but is efficiently removed by an exogenous esterase. This strategy allows facile targeting of dyes and drugs in complex biological environments to label specific cell types, illuminate gap junction connectivity, and pharmacologically perturb distinct subsets of cells. We expect this approach to have general utility for the specific delivery of many small molecules to defined cellular populations.
Two independent switches regulate cytoplasmic dynein’s processivity and directionality
Authors: Walter Wilhelm J. , Koonce Michael P. , Brenner Bernhard , Steffen Walter
Published: March 2012

Cytoplasmic dynein is a microtubule-based molecular motor that participates in a multitude of cell activities, from cell division to organelle transport. Unlike kinesin and myosin, where different tasks are performed by highly specialized members of these superfamilies, a single form of the dynein heavy chain is utilized for different functions. This versatility demands an extensive regulation of motor function. Using an improved application of an optical trap, we were now able to demonstrate that cytoplasmic dynein can generate a discrete power stroke as well as a processive walk in either direction; i.e., towards the plus- or towards the minus-end of a microtubule. Thus, dynein’s motor functions can be described by four basic modes of motion: processive and nonprocessive movement, and movement in the forward and reverse directions. Importantly, these four modes of movement can be controlled by two switches. One switch, based on phosphate, determines the directionality of movement. The second switch, depending on magnesium, converts cytoplasmic dynein from a nonprocessive to a processive motor. The two switches can be triggered separately or jointly by changing concentrations of phosphate and magnesium in the local environment. The control of four modes of movement by two switches has major implications for our understanding of the cellular functions and regulation of cytoplasmic dynein. Based on recent studies of dynein’s structure we are able to draw new conclusions on cytoplasmic dynein’s stepping mechanism.
M phase phosphorylation of the epigenetic regulator UHRF1 regulates its physical association with the deubiquitylase USP7 and stability
Authors: Ma Honghui , Chen Hao , Guo Xue , Wang Zhentian , Sowa Mathew E. , Zheng Lijuan , Hu Shibin , Zeng Pingyao , Guo Rui , Diao Jianbo , Lan Fei , Harper J. Wade , Shi Yujiang Geno , Xu Yanhui , Shi Yang
Published: March 2012

UHRF1 (Ubiquitin-like, with PHD and RING finger domains 1) plays an important role in DNA CpG methylation, heterochromatin function and gene expression. Overexpression of UHRF1 has been suggested to contribute to tumorigenesis. However, regulation of UHRF1 is largely unknown. Here we show that the deubiquitylase USP7 interacts with UHRF1. Using interaction-defective and catalytic mutants of USP7 for complementation experiments, we demonstrate that both physical interaction and catalytic activity of USP7 are necessary for UHRF1 ubiquitylation and stability regulation. Mass spectrometry analysis identified phosphorylation of serine (S) 652 within the USP7-interacting domain of UHRF1, which was further confirmed by a UHRF1 S652 phosphor (S652ph)-specific antibody. Importantly, the S652ph antibody identifies phosphorylated UHRF1 in mitotic cells and consistently S652 can be phosphorylated by the M phase-specific kinase CDK1-cyclin B in vitro. UHRF1 S652 phosphorylation significantly reduces UHRF1 interaction with USP7 in vitro and in vivo, which is correlated with a decreased UHRF1 stability in the M phase of the cell cycle. In contrast, UHRF1 carrying the S652A mutation, which renders UHRF1 resistant to phosphorylation at S652, is more stable. Importantly, cells carrying the S652A mutant grow more slowly suggesting that maintaining an appropriate level of UHRF1 is important for cell proliferation regulation. Taken together, our findings uncovered a cell cycle-specific signaling event that relieves UHRF1 from its interaction with USP7, thus exposing UHRF1 to proteasome-mediated degradation. These findings identify a molecular mechanism by which cellular UHRF1 level is regulated, which may impact cell proliferation.
Oil sands mining and reclamation cause massive loss of peatland and stored carbon
Authors: Rooney Rebecca C. , Bayley Suzanne E. , Schindler David W.
Published: March 2012

We quantified the wholesale transformation of the boreal landscape by open-pit oil sands mining in Alberta, Canada to evaluate its effect on carbon storage and sequestration. Contrary to claims made in the media, peatland destroyed by open-pit mining will not be restored. Current plans dictate its replacement with upland forest and tailings storage lakes, amounting to the destruction of over 29,500 ha of peatland habitat. Landscape changes caused by currently approved mines will release between 11.4 and 47.3 million metric tons of stored carbon and will reduce carbon sequestration potential by 5,734–7,241 metric tons C/y. These losses have not previously been quantified, and should be included with the already high estimates of carbon emissions from oil sands mining and bitumen upgrading. A fair evaluation of the costs and benefits of oil sands mining requires a rigorous assessment of impacts on natural capital and ecosystem services.
Major taste loss in carnivorous mammals
Authors: Jiang Peihua , Josue Jesusa , Li Xia , Glaser Dieter , Li Weihua , Brand Joseph G. , Margolskee Robert F. , Reed Danielle R. , Beauchamp Gary K.
Published: March 2012

Mammalian sweet taste is primarily mediated by the type 1 taste receptor Tas1r2/Tas1r3, whereas Tas1r1/Tas1r3 act as the principal umami taste receptor. Bitter taste is mediated by a different group of G protein-coupled receptors, the Tas2rs, numbering 3 to ∼66, depending on the species. We showed previously that the behavioral indifference of cats toward sweet-tasting compounds can be explained by the pseudogenization of the
Tas1r2
gene, which encodes the Tas1r2 receptor. To examine the generality of this finding, we sequenced the entire coding region of
Tas1r2
from 12 species in the order Carnivora. Seven of these nonfeline species, all of which are exclusive meat eaters, also have independently pseudogenized
Tas1r2
caused by ORF-disrupting mutations. Fittingly, the purifying selection pressure is markedly relaxed in these species with a pseudogenized
Tas1r2
. In behavioral tests, the Asian otter (defective
Tas1r2
) showed no preference for sweet compounds, but the spectacled bear (intact
Tas1r2
) did. In addition to the inactivation of
Tas1r2
, we found that sea lion
Tas1r1
and
Tas1r3
are also pseudogenized, consistent with their unique feeding behavior, which entails swallowing food whole without chewing. The extensive loss of Tas1r receptor function is not restricted to the sea lion: the bottlenose dolphin, which evolved independently from the sea lion but displays similar feeding behavior, also has all three
Tas1r
s inactivated, and may also lack functional bitter receptors. These data provide strong support for the view that loss of taste receptor function in mammals is widespread and directly related to feeding specializations.
Reconfigurable interactions and three-dimensional patterning of colloidal particles and defects in lamellar soft media
Authors: Trivedi Rahul P. , Klevets Ivan I. , Senyuk Bohdan , Lee Taewoo , Smalyukh Ivan I.
Published: March 2012

Colloidal systems find important applications ranging from fabrication of photonic crystals to direct probing of phenomena typically encountered in atomic crystals and glasses. New applications—such as nanoantennas, plasmonic sensors, and nanocircuits—pose a challenge of achieving sparse colloidal assemblies with tunable interparticle separations that can be controlled at will. We demonstrate reconfigurable multiscale interactions and assembly of colloids mediated by defects in cholesteric liquid crystals that are probed by means of laser manipulation and three-dimensional imaging. We find that colloids attract via distance-independent elastic interactions when pinned to the ends of cholesteric oily streaks, line defects at which one or more layers are interrupted. However, dislocations and oily streaks can also be optically manipulated to induce kinks, allowing one to lock them into the desired configurations that are stabilized by elastic energy barriers for structural transformation of the particle-connecting defects. Under the influence of elastic energy landscape due to these defects, sublamellar-sized colloids self-assemble into structures mimicking the cores of dislocations and oily streaks. Interactions between these defect-embedded colloids can be varied from attractive to repulsive by optically introducing dislocation kinks. The reconfigurable nature of defect–particle interactions allows for patterning of defects by manipulation of colloids and, in turn, patterning of particles by these defects, thus achieving desired colloidal configurations on scales ranging from the size of defect core to the sample size. This defect-colloidal sculpturing may be extended to other lamellar media, providing the means for optically guided self-assembly of mesoscopic composites with predesigned properties.
Regulation of neuroblastoma differentiation by forkhead transcription factors FOXO1/3/4 through the receptor tyrosine kinase PDGFRA
Authors: Mei Yang , Wang Zhanxiang , Zhang Lei , Zhang Yiru , Li Xiaoyu , Liu Huihui , Ye Jing , You Han
Published: March 2012

Neuroblastoma is a common childhood malignant tumor originated from the neural crest-derived sympathetic nervous system. A crucial early event in neuroblastoma pathogenesis is arrested differentiation of neuroblasts at various stages. Treatment of neuroblastoma with TPA and PDGF-BB leads to terminal differentiation of neuroblastoma cells. However, the signaling pathways that are involved in this process remain largely unknown. Here, we report that inhibition of endogenous FOXO proteins attenuated TPA/PDGF-BB mediated differentiation of neuroblastoma cells. Activated FOXO transcription factors acted on PDGFRA promoter to direct its basal mRNA expression as well as its induction upon serum deprivation. Depletion of endogenous PDGFRA in neuroblastoma cells significantly diminished neurite formation and extension under TPA/PDGF-BB treatment. Furthermore, ectopic expression of PDGFRA abolished the blockage of neuroblastoma differentiation by FOXOs inhibition. These findings define the FOXO–PDGFRA axis as crucial mechanistic components that govern TPA-induced neuroblastoma differentiation.
Bacterial rheotaxis
Authors: Marcos  , Fu Henry C. , Powers Thomas R. , Stocker Roman
Published: March 2012

The motility of organisms is often directed in response to environmental stimuli. Rheotaxis is the directed movement resulting from fluid velocity gradients, long studied in fish, aquatic invertebrates, and spermatozoa. Using carefully controlled microfluidic flows, we show that rheotaxis also occurs in bacteria. Excellent quantitative agreement between experiments with
Bacillus subtilis
and a mathematical model reveals that bacterial rheotaxis is a purely physical phenomenon, in contrast to fish rheotaxis but in the same way as sperm rheotaxis. This previously unrecognized bacterial taxis results from a subtle interplay between velocity gradients and the helical shape of flagella, which together generate a torque that alters a bacterium's swimming direction. Because this torque is independent of the presence of a nearby surface, bacterial rheotaxis is not limited to the immediate neighborhood of liquid–solid interfaces, but also takes place in the bulk fluid. We predict that rheotaxis occurs in a wide range of bacterial habitats, from the natural environment to the human body, and can interfere with chemotaxis, suggesting that the fitness benefit conferred by bacterial motility may be sharply reduced in some hydrodynamic conditions.
Governing epidermal homeostasis by coupling cell–cell adhesion to integrin and growth factor signaling, proliferation, and apoptosis
Authors: Livshits Geulah , Kobielak Agnieszka , Fuchs Elaine
Published: March 2012

Cadherin/catenin-based adhesions coordinate cellular growth, survival, migration, and differentiation within a tissue by mechanically anchoring cells to their neighbors. They also intersect with diverse signaling pathways in development and cancer. Although the adhesive functions of adherens junction proteins are well characterized, their contribution to other signaling pathways is less well understood. Here, we show that ablation of α-catenin in the epidermis selectively induces apoptosis in suprabasal differentiating keratinocytes while sparing basal cell progenitors. This protection from death is coupled to elevated focal adhesion signaling, faster migration, and an altered distribution of growth factor receptors. We show that simultaneous depletion of α-catenin and focal adhesion kinase or p21-activated kinase eliminates basal cell protection as well as the elevated migration and proliferation of cells. The increased dependency of cells upon matrix interactions for their survival when cell–cell adhesions are destabilized has important implications for cancer progression and metastasis.
Pepper insects and their control.
Authors: Ghidiu G. M. , Kuhar T. P.
Published: March 2012

This chapter describes the biological development, life cycle, feeding behaviour and control (mainly chemical, cultural and integrated control methods) of the following arthropod pests of pepper (Capsicum spp.): lepidopterous (Lepidoptera) pests, aphids (Aphidoidea), pepper weevil (Anthonomus eugenii), broad mite (Polyphagotarsonemus latus), Cyclamen mite (Steneotarsonemus pallidus [Phytonemus pallidus]), two-spotted spider mite (Tetranychus urticae), pepper maggot (Zonosemata electa), thrips (Thripidae), vegetable leaf miner (Liriomyza sativae), and true bugs (Hemiptera). Recent advances in research on pesticide chemistry that may lead to the development of safer, effective alternatives to multiple applications of broad-spectrum insecticides are discussed.
A Landscape‐Based Classification of Fish Assemblages in Sampled and Unsampled Lakes
Authors: Wehrly Kevin E. , Breck James E. , Wang Lizhu , Szabo‐Kraft Lidia
Published: March 2012

We related fish species patterns and landscape‐scale environmental data from 216 Michigan lakes to identify repeatable types of fish assemblages, identify environmental factors related to assemblage types, and classify fish assemblages in unsampled lakes. Multivariate regression tree modeling of fish species abundances identified six assemblage types that were explained by degree‐days during the ice‐free period, lake surface area, and mean lake surface temperature. Warmwater species dominated southern lakes, while coolwater and coldwater species had higher abundances in northern lakes. Coolwater species were present in large southern lakes, whereas warmwater species were excluded from northern lakes that had low mean surface temperatures or low degree‐days. These results suggest that patterns of lake fish assemblages are shaped by differences in climate as well as lake‐specific differences in surface temperature regimes and in vertical availability of coldwater and coolwater habitats. Because we related fish patterns to readily available landscape‐level data, our approach can be used to characterize fish assemblages in all lakes across broad geographic extents.
Resonance Raman Spectroscopic and Theoretical Study of Geometry Distortion of Thiourea in 21A State
Authors: Zhang Hai-bo , Zhao Yan-ying , Zheng Xu-ming
Published: March 2012

The A-band resonance Raman spectra of thiourea were obtained in water and acetonitrile solution. B3LYP/6-311++G(3df,3pd) and RCIS/6-311++G(3df,3pd) calculations were done to elucidate the ultraviolet electronic transitions, the distorted geometry structure and the saddle point of thiourea in 21A excited state, respectively. The resonance Raman spectra were assigned. The absorption spectrum and resonance Raman intensities were modeled using Heller's time-dependent wavepacket approach to resonance Raman scattering. The results indicate that largest change in the displacement takes place with the C=S stretch mode ν6 (|Δ|=0.95) and noticeable changes appear in the H5N3H6+H8N4H7 wag ν5 (|Δ|=0.19), NCN symmetric stretch+C=S stretch+N3H6+H8N4 wag ν4 (|Δ|=0.18), while the moderate intensities of 2ν15 and 4ν15 are mostly due to the large excited state frequency changes of ν15, but not due to its significant change in the normal mode displacement. The mechanism of the appearance of even overtones of the S=CN2 out of plane deformation is explored. The results indicate that a Franck-Condon region saddle point is the driving force for the quadric phonon mechanism within the standard A-term of resonance Raman scattering, which leads to the pyramidalization of the carbon center and the geometry distortion of thiourea molecule in 21A excited state.
Preparation of Hollow Silica Microspheres via Poly(N-isopropylacrylamide)
Authors: Wang Mo-zhen , Chen Yu-chen , Ge Xue-ping , Ge Xue-wu
Published: March 2012

Core-shell structured SiO2/poly(N-isopropylacrylamide) (SiO2/PNIPAM) microspheres were successfully fabricated through hydrolysis and condensation reaction of tertraethyl orthosilicate (TEOS) on the surface of PNIPAM template at 50 °C. The PNIPAM template can be easily removed by water at room temperature so that SiO2 hollow microspheres were finally obtained. The transmission electron microscope and scanning electron microscope observations indicated that SiO2 hollow microspheres with an average diameter of 150 nm can be formed only if there are enough concentration of PNIPAM and TEOS, and the hydrolysis time of TEOS. FTIR analysis showed that part of PNIPAM remained on the wall of SiO2 because of the strong interaction between PNIPAM and silica. This work provides a clean and efficient way to prepare hollow microspheres.
Carbon, Nitrogen, and Chalcogen Substitution Effects on 2,1,3-Benzothiadiazole Derivative: Theoretical Investigations of Electronic, Optical, and Charge Transport Properties
Authors: Hu Bo , Yao Chan , Wang Qing-wei , Zhang Hao , Yu Jian-kang
Published: March 2012

A series of CH2, NH, O, and Se substituted 2,1,3-benzothiadiazole derivatives have been designed and investigated computationally to elucidate their potential as organic light-emitting materials for organic light-emitting diodes. Both ab initio Hartree-Fock and hybrid density functional methods are used. It is found that adjusting the central aromatic ring by replacing S by CH2, NH, O, and Se makes it possible to fine-tune the electronic, optical, and charge transport properties of the pristine molecule.
Gas Phase Conformations of Tetrapeptide Glycine-Phenylalanine-Glycine-Glycine
Authors: Chen Hui-bin , Wang Yao , Chen Xin , Lin Zi-jing
Published: March 2012

Systematic search of the potential energy surface of tetrapeptide glycine-phenylalanine-glycine-glycine (GFGG) in gas phase is conducted by a combination of PM3, HF and BHandHLYP methods. The conformational search method is described in detail. The relative electronic energies, zero point vibrational energies, dipole moments, rotational constants, vertical ionization energies and the temperature dependent conformational distributions for a number of important conformers are obtained. The structural characteristics of these conformers are analyzed and it is found that the entropic effect is a dominating factor in determining the relative stabilities of the conformers. The measurements of dipole moments and some characteristic IR mode are shown to be effective approaches to verify the theoretical prediction. The structures of the low energy GFGG conformers are also analyzed in their connection with the secondary structures of proteins. Similarity between the local structures of low energy GFGG conformers and the α-helix is discussed and many β- and γ-turn local structures in GFGG conformers are found.
Mapping schemes realizable by obstructed topological polynomials
Authors: Kelsey Gregory
Published: March 2012

In 1985, Levy used a theorem of Berstein to prove that all hyperbolic topological polynomials are equivalent to complex polynomials. We prove a partial converse to the Berstein-Levy Theorem: given post-critical dynamics that are in a sense strongly non-hyperbolic, we prove the existence of topological polynomials which are not equivalent to any complex polynomial that realize these post-critical dynamics. This proof employs the theory of self-similar groups to demonstrate that a topological polynomial admits an obstruction and produces a wealth of examples of obstructed topological polynomials.
Tomato RNA polymerase II interacts with the rod-like conformation of the left terminal domain of the potato spindle tuber viroid positive RNA genome
Authors: Bojić Teodora , Beeharry Yasnee , Zhang Da Jiang , Pelchat Martin
Published: March 2012

Potato spindle tuber viroid (PSTVd) is a small, single-stranded, circular, non-coding RNA pathogen. Host DNA-dependent RNA polymerase II (RNAP II) was proposed to be critical for its replication, but no interaction site for RNAP II on the PSTVd RNA genome was identified. Using a co-immunoprecipitation strategy involving a mAb specific for the conserved heptapeptide (i.e. YSPTSPS) located at the carboxy-terminal domain of the largest subunit of RNAP II, we established the interaction of tomato RNAP II with PSTVd RNA and showed that RNAP II associates with the left terminal domain of PSTVd (+) RNA. RNAP II did not interact with any of several PSTVd (−) RNAs tested. Deletion and site-directed mutagenesis of a shortened model PSTVd (+) RNA fragment were used to identify the role of specific nucleotides and structural motifs in this interaction. Our results provide evidence for the interaction of a RNAP II complex from a natural host with the rod-like conformation of the left terminal domain of PSTVd (+) RNA.
Mushroom bodies of the honeybee brain show cell population-specific plasticity in expression of amine-receptor genes
Authors: McQuillan H. James , Nakagawa Shinichi , Mercer Alison R.
Published: March 2012

Dopamine and octopamine released in the mushroom bodies of the insect brain play a critical role in the formation of aversive and appetitive memories, respectively. As recent evidence suggests a complex relationship between the effects of these two amines on the output of mushroom body circuits, we compared the expression of dopamine- and octopamine-receptor genes in three major subpopulations of mushroom body intrinsic neurons (Kenyon cells). Using the brain of the honeybee,Apis mellifera, we found that expression of amine-receptor genes differs markedly across Kenyon cell subpopulations. We found, in addition, that levels of expression of these genes change dramatically during the lifetime of the bee and that shifts in expression are cell population-specific. Differential expression of amine-receptor genes in mushroom body neurons and the plasticity that exists at this level are features largely ignored in current models of mushroom body function. However, our results are consistent with the growing body of evidence that short- and long-term olfactory memories form in different regions of the mushroom bodies of the brain and that there is functional compartmentalization of the modulatory inputs to this multifunctional brain center.
Application of DEN refinement and automated model building to a difficult case of molecular-replacement phasing: the structure of a putative succinyl-diaminopimelate desuccinylase from Corynebacterium glutamicum
Authors: Brunger Axel T. , Das Debanu , Deacon Ashley M. , Grant Joanna , Terwilliger Thomas C. , Read Randy J. , Adams Paul D. , Levitt Michael , Schröder Gunnar F.
Published: March 2012

Phasing by molecular replacement remains difficult for targets that are far from the search model or in situations where the crystal diffracts only weakly or to low resolution. Here, the process of determining and refining the structure of Cgl1109, a putative succinyl-diaminopimelate desuccinylase from Corynebacterium glutamicum, at ∼3 Å resolution is described using a combination of homology modeling with MODELLER, molecular-replacement phasing with Phaser, deformable elastic network (DEN) refinement and automated model building using AutoBuild in a semi-automated fashion, followed by final refinement cycles with phenix.refine and Coot. This difficult molecular-replacement case illustrates the power of including DEN restraints derived from a starting model to guide the movements of the model during refinement. The resulting improved model phases provide better starting points for automated model building and produce more significant difference peaks in anomalous difference Fourier maps to locate anomalous scatterers than does standard refinement. This example also illustrates a current limitation of automated procedures that require manual adjustment of local sequence misalignments between the homology model and the target sequence.
Low-resolution refinement tools in REFMAC5
Authors: Nicholls Robert A. , Long Fei , Murshudov Garib N.
Published: March 2012

Two aspects of low-resolution macromolecular crystal structure analysis are considered: (i) the use of reference structures and structural units for provision of structural prior information and (ii) map sharpening in the presence of noise and the effects of Fourier series termination. The generation of interatomic distance restraints by ProSMART and their subsequent application in REFMAC5 is described. It is shown that the use of such external structural information can enhance the reliability of derived atomic models and stabilize refinement. The problem of map sharpening is considered as an inverse deblurring problem and is solved using Tikhonov regularizers. It is demonstrated that this type of map sharpening can automatically produce a map with more structural features whilst maintaining connectivity. Tests show that both of these directions are promising, although more work needs to be performed in order to further exploit structural information and to address the problem of reliable electron-density calculation.
catena-Poly[[tetrakis(1H-pyrazole-κN2)copper(II)]-μ-hexafluoridosilicato-κ2F:F′]
Authors: Li Hui , Han Qiuping , Chai Xiaochuan , Wang Jian , Yao Chenzhong
Published: March 2012

In the title one-dimensional coordination polymer, [Cu(SiF6)(C3H4N2)4]n, the CuIIatom is coordinated by two hexafluoridosilicate F atoms and four pyrazole N atoms in a distortedtrans-CuF2N4octahedral environment. The dihedral angle between the planes of the pyrazlole rings in the asymmetric unit is 74.4 (3)°. The hexafluoridosilicate dianion acts as a bridging ligand, connecting the CuIIatoms into a [1-10] chain. The Cu and Si atoms lie on special positions with 2/msite symmetry. In the crystal, intrachain N—H...F hydrogen bonds occur and weak C—H...F interactions link the chains.
(2,2′-Bipyridine-6,6′-dicarboxylato-κ3N,N′,O6)(6′-carboxy-2,2′-bipyridine-6-carboxylato-κ3N,N′,O6)cobalt(III)
Authors: Wang Huimin , Gu Xiaojun , Zhang Bingbing , Su Haiquan
Published: March 2012

The CoIIIatom in the title compound, [Co(C12H6N2O4)(C12H7N2O4)], is six-coordinated in a distorted octahedral geometry by four N atoms and two O atoms of the chelating 2,2′-bipyridine-6,6′-dicarboxylate and 6′-carboxy-2,2′-bipyridine-6-carboxylate ligands. Intermolecular O—H...O hydrogen bonds and face-to-face π-stacking interactions [centroid–centroid distance = 3.6352 (16) Å] between inversion-related pyridine rings link adjacent mononuclear units into a two-dimensional supramolecular structure, and several intermolecular C—H...O interactions are also observed.
3,5-Dimethyl-1-(4-nitrobenzyl)pyridinium bis(benzene-1,2-dithiolato-κ2S,S′)nickelate(III)
Authors: Liu Guang-Xiang
Published: March 2012

The asymmetric unit of the title compound, (C14H15N2O2)[Ni(C6H4S2)2], contains one cation and two halves of two centrosymmetric crystallographically independent anions. In the anions, the NiIIIatoms are coordinated by four S atoms in a distorted square-planar geometry. In the cation, the dihedral angle between the pyridine and benzene rings is 88.66 (17)°. In the crystal, anions and cations interact through C—H...S and C—H...O hydrogen bonds.
3-Chloro-4-methylquinolin-2(1H)-one
Authors: Kassem Mohamed G. , Ghabbour Hazem A. , Abdel-Aziz Hatem A. , Fun Hoong-Kun , Ooi Chin Wei
Published: March 2012

The title compound, C10H8ClNO, is almost planar (r.m.s. deviation for the 13 non-H atoms = 0.023 Å). In the crystal, inversion dimers linked by pairs of N—H...O hydrogen bonds generateR22(8) rings. Weak aromatic π–π stacking interactions [centroid–centroid distance = 3.7622 (12) Å] also occur.
cis-Bis[(4-nitrophenyl)cyanamido-κN1]bis(1,10-phenanthroline-κ2N,N′)nickel(II) methanol monosolvate
Authors: Chiniforoshan Hossein , Jazestani Mehdi , Notash Behrouz
Published: March 2012

In the title compound, [Ni(C7H4N3O2)2(C12H8N2)2]·CH3OH, the NiIIatom is six-coordinated in a distorted N6octahedral geometry and is chelated by two phenanthroline ligands and two phenylcyanamide groups which occupycispositions. The (4-nitrophenyl)cyanamide anions act as monodentate ligands. There is one classical intermolecular O—H...N hydrogen bond and several C—H...O hydrogen bonds are also observed.
5-(2-Chlorobenzyl)-4,5,6,7-tetrahydrothieno[3,2-c]pyridin-2-yl acetate
Authors: Yang Jing , Chen Na , Sun Hao , Cao Xiao-Xia , Liu Deng-Ke
Published: March 2012

In the title compound, C16H16ClNO2S, the benzene and thiophene rings make a dihedral angle of 72.60 (4)°. In the crystal, weak C—H...O interactions are observed.
6H,13H-5,12:7,14-Dimethanodinaphtho[2,3-d:2,3-i][1,3,6,8]tetraazecine
Authors: Rivera Augusto , Maldonado Mauricio , Ríos-Motta Jaime , Fejfarová Karla , Dušek Michal
Published: March 2012

In the title compound, C24H20N4, obtained through the condensation of naphthalene-2,3-diamine with formaldehyde in methanol, the molecule is located on a special position of site symmetry -4. Due to symmetry considerations, the aromatic rings are strictly perpendicular to each other. In the crystal, molecules are linked by pairs of C—H...π interactions into columns along [110].
Poly[(μ4-benzene-1,3,5-tricarboxylato)bis(N,N-dimethylacetamide)terbium(III)]
Authors: Liu Kun
Published: March 2012

The title compound, [Tb(C9H3O6)(C4H9NO)2], shows a rare-earth three-dimensional metal-organic framework structure. In this complex of an eight-coordinated Tb3+ion, the asymmetric unit contains one benzene-1,3,5-tricarboxylic ligand and two coordinated dimethylacetamide molecules. Each Tb3+ion is coordinated by six O atoms from four carboxylate groups of the benzene-1,3,5-tricarboxylic ligands and two O atoms from two terminal dimethylacetamide molecules.
cis-Tetraaquabis{5-[4-(1H-imidazol-1-yl-κN3)phenyl]tetrazolido}manganese(II) dihydrate
Authors: Wang Xin , Yan Shi-Wei , Chang Suo-Cheng , Liang Yan-Chen , Zhang Fu-Tian
Published: March 2012

In the title compound, [Mn(C10H7N6)2(H2O)4]·2H2O, the complex unit comprises an Mn2+ion, coordinated by two imidazole N atoms fromcis-related monodentate 5-[4-(imidazol-1-yl)phenyl]tetrazolide ligands and four water molecules, together with two water molecules of solvation. The Mn2+ion lies on a twofold rotation axis and has a slightly distorted octahedral geometry. The molecules are connected by O—H...N and O—H...O hydrogen bonds involving both coordinated and solvent water molecules, generating a three-dimensional structure. Two C atoms of the imidazole ring of the ligand are each disordered over two sites with occupancy factors of 0.75 and 0.25.
9-(4-Hydroxy-3,5-dimethoxyphenyl)-3,3,6,6-tetramethyl-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H)-dione
Authors: Sughanya V. , Sureshbabu N.
Published: March 2012

In the title compound, C25H30O6, the two fused cyclohexanone rings have envelope conformations, whereas the central pyran ring is roughly planar [mximum deviation = 0.045 (2) Å]. The pyran and benzene rings are almost perpendicular to each other, making a dihedral angle of 86.32 (2)°. In the crystal, molecules are linkedviapairs of O—H...O hydrogen bonds, forming inversion dimers.
Triethylammonium (indane-1,2,3-trione 1,2-dioximato-κ2N1,O2)(indane-1,2,3-trione 2-oximato 1-oxime-κ2N1,O2)nickel(II)
Authors: Zhong Baoyun , Li Shengli , Chen Guifang
Published: March 2012

In the title compound, (C6H16N)[Ni(C9H4N2O3)(C9H5N2O3)], the NiIIion is four-coordinated by two N atoms and two O atoms from two indane-1,2,3-trione-1,2-dioxime ligands. The two organic ligands are linked by an intramolecular O—H...O hydrogen bond. In the crystal, molecules are linked by N—H...O hydrogen-bonds.
Retracted: Meta‐analysis on the comparison between two topical calcineurin inhibitors in atopic dermatitis
Authors: YIN Zhi Qiang , ZHANG Wei Ming , SONG Guo Xin , LUO Dan
Published: March 2012

Topical calcineurin inhibitors have proved to be suitable for the treatment of AD. We conducted a meta‐analysis comparing efficacy and tolerance of tacrolimus with pimecrolimus in treatment of AD. According to our meta‐analysis, tacrolimus 0.1% was more effective than pimecrolimus 1% in adult patients (week 3: risk ratio [RR] 0.55, 95% confidence interval [CI] 0.42–0.73), and tacrolimus (a combination of 0.03% and 0.1%) was also more effective than pimecrolimus 1% in pediatric patients (week 6/end of study: RR 0.76, 95% CI 0.63–0.92). Regardless of age or illness severity, tacrolimus 0.1% had higher efficacy than pimecrolimus 1% in the treatment of AD (week 3: RR 0.55, 95% CI 0.42–0.72). In adult patients, tacrolimus 0.1% had more adverse events than pimecrolimus 1% (RR 1.30, 95% CI 1.02–1.66), but the incidence of adverse events between tacrolimus 0.1% (or 0.03%) and pimecrolimus 1% was not significantly different in pediatric patients. No matter whether the patients were adult or pediatric, more pimecrolimus‐treated patients withdrew from the trials because of a lack of efficacy. Regardless of age and illness severity, more pimecrolimus 1%‐treated patients withdrew from the trials because of a lack of efficacy, compared with tacrolimus 0.1% (or 0.03%)‐treated patients. More pimecrolimus‐treated pediatric patients withdrew from the trials because of adverse events (RR 0.26, 95% CI 0.1–0.68). More pimecrolimus 1%‐treated patients withdrew from the trials because of adverse events, compared with tacrolimus 0.03%‐treated patients, regardless of age (RR 0.1, 95% CI 0.02–0.53). In conclusion, tacrolimus ointment has higher efficacy and better tolerance than pimecrolimus cream in treatment of AD.
Chemoimmunotherapy with ofatumumab in combination with CHOP in previously untreated follicular lymphoma
Authors: Czuczman Myron S. , Hess Georg , Gadeberg Ole V. , Pedersen Lars M. , Goldstein Nancy , Gupta Ira , Jewell Roxanne C. , Lin Thomas S. , Lisby Steen , Strange Claus , Windfeld Kristian , Viardot Andreas ,   for the 409 Study Investigators
Published: March 2012

An international, Phase II trial was conducted to assess two doses of ofatumumab, a human CD20 monoclonal antibody, combined with cyclophosphamide (750 mg/m2), doxorubicin (50 mg/m2), prednisone (100 mg days 3–7) and vincristine (1·4 mg/m2) (O‐CHOP), as frontline treatment for follicular lymphoma (FL). 59 patients with previously untreated FL were randomized to ofatumumab 500 mg (n = 29) or 1000 mg (n = 30) day 1, with CHOP on day 3 every 3 weeks for six cycles. Median duration of FL was 0·1 years for both dose groups; 34% and 38% of patients had high‐risk Follicular Lymphoma International Prognostic Index (FLIPI) scores in the 500‐ and 1000‐mg dose groups, respectively. Overall response rate was 90% for the 500‐mg group and 100% for the 1000‐mg group. 62% of patients achieved complete response (CR)/unconfirmed CR (CRu). 76% of patients with FLIPI score 3–5 attained CR/CRu. Longer follow‐up time is needed for analysis of survival end points. The most common Common Terminology Criteria grade 3–4 investigator‐reported adverse events were leucopenia (29%) and neutropenia (22%). No deaths have been reported. O‐CHOP was safe and efficacious in patients with previously untreated FL, including high‐risk FLIPI groups. This trial was registered at www.clinicaltrials.gov (NCT00494780).