bluuebunny/crossref_metadata_2025 huggingface dataset:
Modified PRISM theory for confined polymers
Authors: Xu Mengjin , Zhang Chen , Du Zhongjie , Mi Jianguo
Published: November 2012

We propose a modified polymer reference interaction site model (PRISM) to describe the interfacial density profiles of polymers in contact with planar and curved solid surfaces. In the theoretical approach, a bridge function derived from density functional method is included. In description of hard-sphere polymer at planar and curved surfaces with an arbitrary external field, the effect of modification has been validated by the available simulation data, except for low density system. When extended to confined real systems, the modified theoretical model also shows an encouraging prospect in description of the interfacial structure and properties.
Electron energy distribution functions measured by Langmuir probe with optical emission spectroscopy in very high frequency capacitive discharge in nitrogen
Authors: Abdel-Fattah E. , Bazavan M. , Sugai H.
Published: November 2012

By using a rf compensated Langmuir probe and optical emission spectroscopy, the effects of driving frequency (13.56–50 MHz) on the electron energy probability function (EEPF), electron density, electron temperature, and the vibrational and rotational temperatures in capacitively coupled nitrogen discharge were investigated. Measurements were performed in the pressure range 60–200 mTorr, and at a fixed voltage of 140 V (peak-to-peak). With increasing the driving frequency, the dissipated power and electron density markedly increased along with the intensity of the optical emission lines belonging to the 2nd positive (337.1 nm) and 1st negative systems (391.4 nm) of N2. The EEPF at low pressure 60 mTorr is two-temperature (bi-Maxwellian) distribution, irrespective of the driving frequency, in contrast with argon and helium discharges in the similar conditions. The mechanism forming such bi-Maxwellian shape was explained by two combined effects: one is the collisionless sheath-heating effect enhancing the tail electron population, and the other is the collision-induced reduction of electrons at the energy 2–4 eV where the collision cross-section for the vibrational excitation has a resonantly large peak. The two-temperature EEPF structure was basically retained at moderate pressure 120 mTorr and high pressure 200 mTorr. The vibrational temperature Tvib and rotational temperature Trot are measured for the sequence (Δν=−2) of N2 second positive system (C3Πu→B3Πg) using the method of comparing the measured and calculated spectra with a chi-squared minimization procedure. It was found that, both of Tvib and Trot are a weakly dependent on driving frequency at low pressure 60 mTorr. At higher pressure (120 and 200 mTorr), Tvib rises monotonically with the driving frequency, whereas the Trot slightly decreases with frequency below 37 MHz, beyond which it relatively increases or saturated.
Properties of a warm plasma collisional sheath in an oblique magnetic field
Authors: Ou Jing , Yang Jinhong
Published: November 2012

The properties of a warm plasma collisional sheath in an oblique magnetic field and the associated sheath criterion are investigated with a two-fluid model. In the fluid framework, a sheath criterion including effects of the magnetic field and collision is established theoretically for a wide range of ion temperature. With the sheath criterion as the plasma-sheath boundary condition, different plasma parameters including potential, electron and ion densities, and ion velocity are calculated for various ion temperatures and ion thermal motions. It is shown that the properties of the sheath depend not only on the plasma balance equations but also on the sheath boundary conditions. In addition, effects of the directions and magnitudes of the magnetic field on the plasma sheath are also discussed under different ion temperatures.
Excellent dielectric properties of anisotropic polymer composites filled with parallel aligned zinc flakes
Authors: Zhang Ye , Wang Yao , Deng Yuan , Guo Yanjingtian , Bi Wencheng , Li Mao , Luo Yu , Bai Jinbo
Published: November 2012

Orderly polymer composites based on polyvinylidene fluoride assembled with parallel aligned zinc flakes were fabricated by a simple process. It is interesting to note that the microstructure of parallel arrangement could introduce excellent dielectric properties with obvious anisotropic dielectric behaviors. The dielectric constant in the parallel direction was obviously higher than that of the perpendicular direction. And the anisotropic intensity of interfacial polarization is proposed to interpret the anisotropic dielectric constant. Also, an equivalent circuit model of two parallel RC circuits in series, based on the analysis of impedance data, is employed to further discuss the anisotropic dielectric behavior.
Disruption of PH–kinase domain interactions leads to oncogenic activation of AKT in human cancers
Authors: Parikh Chaitali , Janakiraman Vasantharajan , Wu Wen-I , Foo Catherine K. , Kljavin Noelyn M. , Chaudhuri Subhra , Stawiski Eric , Lee Brian , Lin Jie , Li Hong , Lorenzo Maria N. , Yuan Wenlin , Guillory Joseph , Jackson Marlena , Rondon Jesus , Franke Yvonne , Bowman Krista K. , Sagolla Meredith , Stinson Jeremy , Wu Thomas D. , Wu Jiansheng , Stokoe David , Stern Howard M. , Brandhuber Barbara J. , Lin Kui , Skelton Nicholas J. , Seshagiri Somasekar
Published: November 2012

The protein kinase v-akt murine thymoma viral oncogene homolog (AKT), a key regulator of cell survival and proliferation, is frequently hyperactivated in human cancers. Intramolecular pleckstrin homology (PH) domain–kinase domain (KD) interactions are important in maintaining AKT in an inactive state. AKT activation proceeds after a conformational change that dislodges the PH from the KD. To understand these autoinhibitory interactions, we generated mutations at the PH–KD interface and found that most of them lead to constitutive activation of AKT. Such mutations are likely another mechanism by which activation may occur in human cancers and other diseases. In support of this likelihood, we found somatic mutations in
AKT1
at the PH–KD interface that have not been previously described in human cancers. Furthermore, we show that the
AKT1
somatic mutants are constitutively active, leading to oncogenic signaling. Additionally, our studies show that the
AKT1
mutants are not effectively inhibited by allosteric AKT inhibitors, consistent with the requirement for an intact PH–KD interface for allosteric inhibition. These results have important implications for therapeutic intervention in patients with
AKT
mutations at the PH–KD interface.
Volume conservation principle involved in cell lengthening and nucleus movement during tissue morphogenesis
Authors: Gelbart Michael A. , He Bing , Martin Adam C. , Thiberge Stephan Y. , Wieschaus Eric F. , Kaschube Matthias
Published: November 2012

Tissue morphogenesis is the process in which coordinated movements and shape changes of large numbers of cells form tissues, organs, and the internal body structure. Understanding morphogenetic movements requires precise measurements of whole-cell shape changes over time. Tissue folding and invagination are thought to be facilitated by apical constriction, but the mechanism by which changes near the apical cell surface affect changes along the entire apical–basal axis of the cell remains elusive. Here, we developed Embryo Development Geometry Explorer, an approach for quantifying rapid whole-cell shape changes over time, and we combined it with deep-tissue time-lapse imaging based on fast two-photon microscopy to study
Drosophila
ventral furrow formation. We found that both the cell lengthening along the apical–basal axis and the movement of the nucleus to the basal side proceeded stepwise and were correlated with apical constriction. Moreover, cell volume lost apically due to constriction largely balanced the volume gained basally by cell lengthening. The volume above the nucleus was conserved during its basal movement. Both apical volume loss and cell lengthening were absent in mutants showing deficits in the contractile cytoskeleton underlying apical constriction. We conclude that a single mechanical mechanism involving volume conservation and apical constriction-induced basal movement of cytoplasm accounts quantitatively for the cell shape changes and the nucleus movement in
Drosophila
ventral furrow formation. Our study provides a comprehensive quantitative analysis of the fast dynamics of whole-cell shape changes during tissue folding and points to a simplified model for
Drosophila
gastrulation.
Host–virus dynamics and subcellular controls of cell fate in a natural coccolithophore population
Authors: Vardi Assaf , Haramaty Liti , Van Mooy Benjamin A. S. , Fredricks Helen F. , Kimmance Susan A. , Larsen Aud , Bidle Kay D.
Published: November 2012

Marine viruses are major evolutionary and biogeochemical drivers in marine microbial foodwebs. However, an in-depth understanding of the cellular mechanisms and the signal transduction pathways mediating host–virus interactions during natural bloom dynamics has remained elusive. We used field-based mesocosms to examine the “arms race” between natural populations of the coccolithophore
Emiliania huxleyi
and its double-stranded DNA-containing coccolithoviruses (EhVs). Specifically, we examined the dynamics of EhV infection and its regulation of cell fate over the course of bloom development and demise using a diverse suite of molecular tools and in situ fluorescent staining to target different levels of subcellular resolution. We demonstrate the concomitant induction of reactive oxygen species, caspase-specific activity, metacaspase expression, and programmed cell death in response to the accumulation of virus-derived glycosphingolipids upon infection of natural
E. huxleyi
populations. These subcellular responses to viral infection simultaneously resulted in the enhanced production of transparent exopolymer particles, which can facilitate aggregation and stimulate carbon flux. Our results not only corroborate the critical role for glycosphingolipids and programmed cell death in regulating
E. huxleyi
–EhV interactions, but also elucidate promising molecular biomarkers and lipid-based proxies for phytoplankton host–virus interactions in natural systems.
Legacy of human-induced C erosion and burial on soil–atmosphere C exchange
Authors: Van Oost Kristof , Verstraeten Gert , Doetterl Sebastian , Notebaert Bastiaan , Wiaux François , Broothaerts Nils , Six Johan
Published: November 2012

Carbon exchange associated with accelerated erosion following land cover change is an important component of the global C cycle. In current assessments, however, this component is not accounted for. Here, we integrate the effects of accelerated C erosion across point, hillslope, and catchment scale for the 780-km2Dijle River catchment over the period 4000 B.C. to A.D. 2000 to demonstrate that accelerated erosion results in a net C sink. We found this long-term C sink to be equivalent to 43% of the eroded C and to have offset 39% (17–66%) of the C emissions due to anthropogenic land cover change since the advent of agriculture. Nevertheless, the erosion-induced C sink strength is limited by a significant loss of buried C in terrestrial depositional stores, which lagged the burial. The time lag between burial and subsequent loss at this study site implies that the C buried in eroded terrestrial deposits during the agricultural expansion of the last 150 y cannot be assumed to be inert to further destabilization, and indeed might become a significant C source. Our analysis exemplifies that accounting for the non–steady-state C dynamics in geomorphic active systems is pertinent to understanding both past and future anthropogenic global change.
Population-scale sequencing reveals genetic differentiation due to local adaptation in Atlantic herring
Authors: Lamichhaney Sangeet , Barrio Alvaro Martinez , Rafati Nima , Sundström Görel , Rubin Carl-Johan , Gilbert Elizabeth R. , Berglund Jonas , Wetterbom Anna , Laikre Linda , Webster Matthew T. , Grabherr Manfred , Ryman Nils , Andersson Leif
Published: November 2012

The Atlantic herring (
Clupea harengus
), one of the most abundant marine fishes in the world, has historically been a critical food source in Northern Europe. It is one of the few marine species that can reproduce throughout the brackish salinity gradient of the Baltic Sea. Previous studies based on few genetic markers have revealed a conspicuous lack of genetic differentiation between geographic regions, consistent with huge population sizes and minute genetic drift. Here, we present a cost-effective genome-wide study in a species that lacks a genome sequence. We first assembled a muscle transcriptome and then aligned genomic reads to the transcripts, creating an “exome assembly,” capturing both exons and flanking sequences. We then resequenced pools of fish from a wide geographic range, including the Northeast Atlantic, as well as different regions in the Baltic Sea, aligned the reads to the exome assembly, and identified 440,817 SNPs. The great majority of SNPs showed no appreciable differences in allele frequency among populations; however, several thousand SNPs showed striking differences, some approaching fixation for different alleles. The contrast between low genetic differentiation at most loci and striking differences at others implies that the latter category primarily reflects natural selection. A simulation study confirmed that the distribution of the fixation index
F
ST
deviated significantly from expectation for selectively neutral loci. This study provides insights concerning the population structure of an important marine fish and establishes the Atlantic herring as a model for population genetic studies of adaptation and natural selection.
Reciprocity laws through formal groups
Authors: Demchenko Oleg , Gurevich Alexander
Published: November 2012

A relation between formal groups and reciprocity laws is studied following the approach initiated by Honda. Let

ξ
\xi

denote an

m
m

th primitive root of unity. For a character

χ
\chi

of order

m
m

, we define two one-dimensional formal groups over

Z

[
ξ
]

\mathbb {Z}[\xi ]

and prove the existence of an integral homomorphism between them with linear coefficient equal to the Gauss sum of

χ
\chi

. This allows us to deduce a reciprocity formula for the

m
m

th residue symbol which, in particular, implies the cubic reciprocity law.
Fingerloop activates cargo delivery and unloading during cotranslational protein targeting
Authors: Ariosa Aileen R. , Duncan Stacy S. , Saraogi Ishu , Lu Xiaodong , Brown April , Phillips Gregory J. , Shan Shu-Ou
Published: November 2012

During cotranslational protein targeting by the signal recognition particle (SRP), information about signal sequence binding in the SRP's M domain must be effectively communicated to its GTPase domain to turn on its interaction with the SRP receptor (SR) and thus deliver the cargo proteins to the membrane. A universally conserved “fingerloop” lines the signal sequence–binding groove of SRP; the precise role of this fingerloop in protein targeting has remained elusive. In this study, we show that the fingerloop plays important roles in SRP function by helping to induce the SRP into a more active conformation that facilitates multiple steps in the pathway, including efficient recruitment of SR, GTPase activation in the SRP•SR complex, and most significantly, the unloading of cargo onto the target membrane. On the basis of these results and recent structural work, we propose that the fingerloop is the first structural element to detect signal sequence binding; this information is relayed to the linker connecting the SRP's M and G domains and thus activates the SRP and SR for carrying out downstream steps in the pathway.
Comparison of mRNA localization and regulation during endoplasmic reticulum stress inDrosophilacells
Authors: Gaddam Deepika , Stevens Nicole , Hollien Julie
Published: November 2012

Ire1 is an endoplasmic reticulum (ER) transmembrane protein that senses disturbances in protein folding homeostasis and contributes to a multifaceted response to stress. The nuclease activity of Ire1, in addition to splicing the mRNA encoding the transcription factor Xbp1, mediates mRNA degradation in response to ER stress through a pathway termed regulated Ire1-dependent decay (RIDD). We previously showed that ER targeting of substrates is necessary for RIDD; in this paper, we show that ER localization is also sufficient to induce decay in a normally unaffected mRNA. Using microarrays, we also measured relative mRNA degradation in the presence and absence of ER stress in Drosophila S2 cells, and determined mRNA membrane association using detergent fractionation. The vast majority of mRNAs that were strongly associated with the ER were degraded faster during ER stress in an Ire1-dependent manner, suggesting that RIDD is the default pathway for ER-localized mRNAs during stress. We also show that the mRNA encoding plexin A remains highly polysome associated during stress and escapes degradation by RIDD, and that its 5′ untranslated region can protect a strong RIDD target from degradation. These results suggest that while translation is generally attenuated during ER stress, continued translation of certain messages can protect them from degradation by RIDD.
Decoupling nutrient signaling from growth rate causes aerobic glycolysis and deregulation of cell size and gene expression
Authors: Slavov Nikolai , Botstein David
Published: November 2012

To survive and proliferate, cells need to coordinate their metabolism, gene expression, and cell division. To understand this coordination and the consequences of its failure, we uncoupled biomass synthesis from nutrient signaling by growing, in chemostats, yeast auxotrophs for histidine, lysine, or uracil in excess of natural nutrients (i.e., sources of carbon, nitrogen, sulfur, and phosphorus), such that their growth rates (GRs) were regulated by the availability of their auxotrophic requirements. The physiological and transcriptional responses to GR changes of these cultures differed markedly from the respective responses of prototrophs whose growth-rate is regulated by the availability of natural nutrients. The data for all auxotrophs at all GRs recapitulated the features of aerobic glycolysis, fermentation despite high oxygen levels in the growth media. In addition, we discovered wide bimodal distributions of cell sizes, indicating a decoupling between the cell division cycle (CDC) and biomass production. The aerobic glycolysis was reflected in a general signature of anaerobic growth, including substantial reduction in the expression levels of mitochondrial and tricarboxylic acid genes. We also found that the magnitude of the transcriptional growth-rate response (GRR) in the auxotrophs is only 40–50% of the magnitude in prototrophs. Furthermore, the auxotrophic cultures express autophagy genes at substantially lower levels, which likely contributes to their lower viability. Our observations suggest that a GR signal, which is a function of the abundance of essential natural nutrients, regulates fermentation/respiration, the GRR, and the CDC.
Xenon Neuroprotection in Experimental Stroke
Authors: Sheng Siyuan P. , Lei Beilei , James Michael L. , Lascola Christopher D. , Venkatraman Talaignair N. , Jung Jin Yong , Maze Mervyn , Franks Nicholas P. , Pearlstein Robert D. , Sheng Huaxin , Warner David S.
Published: November 2012

Background

Xenon has been proven to be neuroprotective in experimental brain injury. The authors hypothesized that xenon would improve outcome from focal cerebral ischemia with a delayed treatment onset and prolonged recovery interval.

Methods

Rats were subjected to 70 min temporary focal ischemia. Ninety minutes later, rats were treated with 0, 15, 30, or 45% Xe for 20 h or 0 or 30% Xe for 8, 20, or 44 h. Outcome was measured after 7 days. In another experiment, after ischemia, rats were maintained at 37.5° or 36.0°C for 20 h with or without 30% Xe. Outcome was assessed 28 days later. Finally, mice were subjected to intracerebral hemorrhage with or without 30% Xe for 20 h. Brain water content, hematoma volume, rotarod function, and microglial activation were measured.

Results

Cerebral infarct sizes (mean±SD) for 0, 15, 30, and 45% Xe were 212±27, 176±55, 160±32, and 198±54 mm, respectively (P=0.023). Neurologic scores (median±interquartile range) followed a similar pattern (P=0.002). Infarct size did not vary with treatment duration, but neurologic score improved (P=0.002) at all xenon exposure durations (8, 20, and 44 h). Postischemic treatment with either 30% Xe or subtherapeutic hypothermia (36°C) had no effect on 28-day outcome. Combination of these interventions provided long-term benefit. Xenon improved intracerebral hemorrhage outcome measures.

Conclusion

Xenon improved focal ischemic outcome at 7, but not 28 days postischemia. Xenon combined with subtherapeutic hypothermia produced sustained recovery benefit. Xenon improved intracerebral hemorrhage outcome. Xenon may have potential for clinical stroke therapy under carefully defined conditions.
Prediction of Difficult Tracheal Intubation
Authors: Langeron Olivier , Cuvillon Philippe , Ibanez-Esteve Cristina , Lenfant François , Riou Bruno , Le Manach Yannick
Published: November 2012

Background

It has been suggested that predicting difficult tracheal intubation is useless because of the poor predictive capacity of individual signs and scores. The authors tested the hypothesis that an accurate prediction of difficult tracheal intubation using simple clinical signs is possible using a computer-assist model.

Methods

In a cohort of 1,655 patients, the authors analyzed the predictive properties of each of the main signs (Mallampati score, mouth opening, thyromental distance, and body mass index) to predict difficult tracheal intubation. They built the best score possible using a simple logistic model (SCOREClinic) and compared it with the more recently described score in the literature (SCORENaguib). Then they used a boosted tree analysis to build the best score possible using computer-assisted calculation (SCOREComputer).

Results

Difficult tracheal intubation occurred in 101 patients (6.1%). The predictive properties of each sign remain low (maximum area under the receiver operating characteristic curve 0.70). Using receiver operating characteristic curve, the global prediction of the SCOREClinic (0.74, 95% CI: 0.72-0.76) was greater than that of the SCORENaguib (0.66, 95% CI: 0.60-0.72, P<0.001) but significantly lower than that of the SCOREComputer (0.86, 95% CI: 0.84-0.91, P<0.001). The proportion of patients in the inconclusive zone was 71% using SCORENaguib, 56% using SCOREClinic, and only 32 % using SCOREComputer (all P<0.001).

Conclusion

Computer-assisted models using complex interaction between variables enable an accurate prediction of difficult tracheal intubation with a low proportion of patients in the inconclusive zone. An external validation of the model is now required.
Assessment of White Matter Injury and Outcome in Severe Brain Trauma
Authors: Galanaud Damien , Perlbarg Vincent , Gupta Rajiv , Stevens Robert D. , Sanchez Paola , Tollard Eléonore , de Champfleur Nicolas Menjot , Dinkel Julien , Faivre Sébastien , Soto-Ares Gustavo , Veber Benoit , Cottenceau Vincent , Masson Françoise , Tourdias Thomas , André Edith , Audibert Gérard , Schmitt Emmanuelle , Ibarrola Danielle , Dailler Frédéric , Vanhaudenhuyse Audrey , Tshibanda Luaba , Payen Jean-François , Le Bas Jean-François , Krainik Alexandre , Bruder Nicolas , Girard Nadine , Laureys Steven , Benali Habib , Puybasset Louis
Published: November 2012

Background

Existing methods to predict recovery after severe traumatic brain injury lack accuracy. The aim of this study is to determine the prognostic value of quantitative diffusion tensor imaging (DTI).

Methods

In a multicenter study, the authors prospectively enrolled 105 patients who remained comatose at least 7 days after traumatic brain injury. Patients underwent brain magnetic resonance imaging, including DTI in 20 preselected white matter tracts. Patients were evaluated at 1 yr with a modified Glasgow Outcome Scale. A composite DTI score was constructed for outcome prognostication on this training database and then validated on an independent database (n=38). DTI score was compared with the International Mission for Prognosis and Analysis of Clinical Trials Score.

Results

Using the DTI score for prediction of unfavorable outcome on the training database, the area under the receiver operating characteristic curve was 0.84 (95% CI: 0.75-0.91). The DTI score had a sensitivity of 64% and a specificity of 95% for the prediction of unfavorable outcome. On the validation-independent database, the area under the receiver operating characteristic curve was 0.80 (95% CI: 0.54-0.94). On the training database, reclassification methods showed significant improvement of classification accuracy (P < 0.05) compared with the International Mission for Prognosis and Analysis of Clinical Trials score. Similar results were observed on the validation database.

Conclusions

White matter assessment with quantitative DTI increases the accuracy of long-term outcome prediction compared with the available clinical/radiographic prognostic score.
Can Changes in Arterial Pressure be Used to Detect Changes in Cardiac Output during Volume Expansion in the Perioperative Period?
Authors: Le Manach Yannick , Hofer Christoph K. , Lehot Jean-Jacques , Vallet Benoît , Goarin Jean-Pierre , Tavernier Benoît , Cannesson Maxime
Published: November 2012

Background

Cardiac output (CO) is rarely monitored during surgery, and arterial pressure remains the only hemodynamic parameter for assessing the effects of volume expansion (VE). However, whether VE-induced changes in arterial pressure accurately reflect changes in CO has not been demonstrated. The authors studied the ability of VE-induced changes in arterial pressure and in pulse pressure variation to detect changes in CO induced by VE in the perioperative period.

Methods

The authors studied 402 patients in four centers. Hemodynamic variables were recorded before and after VE. Response to VE was defined as more than 15% increase in CO. The ability of VE-induced changes in arterial pressure to detect changes in CO was assessed using a gray zone approach.

Results

VE increased CO of more than 15% in 205 patients (51%). Areas under the receiver operating characteristic curves for VE-induced changes in systolic, diastolic, means, and pulse pressure ranged between 0.64 and 0.70, and sensitivity and specificity ranged between 52 and 79%. For these four arterial pressure-derived parameters, large gray zones were found, and more than 60% of the patients lay within this inconclusive zone. A VE-induced decrease in pulse pressure variation of 3% or more allowed detecting a fluid-induced increase in CO of more than 15% with a sensitivity of 90% and a specificity of 77% and a gray zone between 2.2 and 4.7% decrease in pulse pressure variation including 14% of the patients.

Conclusion

Only changes in pulse pressure variation accurately detect VE-induced changes in CO and have a potential clinical applicability.
Probing articular cartilage damage and disease by quantitative magnetic resonance imaging
Authors: Chan Deva D. , Neu Corey P.
Published: November 2012

Osteoarthritis (OA) is a debilitating disease that reflects a complex interplay of biochemical, biomechanical, metabolic and genetic factors, which are often triggered by injury, and mediated by inflammation, catabolic cytokines and enzymes. An unmet clinical need is the lack of reliable methods that are able to probe the pathogenesis of early OA when disease-rectifying therapies may be most effective. Non-invasive quantitative magnetic resonance imaging (qMRI) techniques have shown potential for characterizing the structural, biochemical and mechanical changes that occur with cartilage degeneration. In this paper, we review the background in articular cartilage and OA as it pertains to conventional MRI and qMRI techniques. We then discuss how conventional MRI and qMRI techniques are used in clinical and research environments to evaluate biochemical and mechanical changes associated with degeneration. Some qMRI techniques allow for the use of relaxometry values as indirect biomarkers for cartilage components. Direct characterization of mechanical behaviour of cartilage is possible via other specialized qMRI techniques. The combination of these qMRI techniques has the potential to fully characterize the biochemical and biomechanical states that represent the initial changes associated with cartilage degeneration. Additionally, knowledge of
in vivo
cartilage biochemistry and mechanical behaviour in healthy subjects and across a spectrum of osteoarthritic patients could lead to improvements in the detection, management and treatment of OA.
On the molecular mechanisms of mitotic kinase activation
Authors: Bayliss Richard , Fry Andrew , Haq Tamanna , Yeoh Sharon
Published: November 2012

During mitosis, human cells exhibit a peak of protein phosphorylation that alters the behaviour of a significant proportion of proteins, driving a dramatic transformation in the cell's shape, intracellular structures and biochemistry. These mitotic phosphorylation events are catalysed by several families of protein kinases, including Auroras, Cdks, Plks, Neks, Bubs, Haspin and Mps1/TTK. The catalytic activities of these kinases are activated by phosphorylation and through protein–protein interactions. In this review, we summarize the current state of knowledge of the structural basis of mitotic kinase activation mechanisms. This review aims to provide a clear and comprehensive primer on these mechanisms to a broad community of researchers, bringing together the common themes, and highlighting specific differences. Along the way, we have uncovered some features of these proteins that have previously gone unreported, and identified unexplored questions for future work. The dysregulation of mitotic kinases is associated with proliferative disorders such as cancer, and structural biology will continue to play a critical role in the development of chemical probes used to interrogate disease biology and applied to the treatment of patients.
Systemic transport of Alfalfa mosaic virus can be mediated by the movement proteins of several viruses assigned to five genera of the 30K family
Authors: Fajardo Thor V. M. , Peiró Ana , Pallás Vicente , Sánchez-Navarro Jesús
Published: November 2012

We previously showed that the movement protein (MP) gene of Alfalfa mosaic virus (AMV) is functionally exchangeable for the cell-to-cell transport of the corresponding genes of Tobacco mosaic virus (TMV), Brome mosaic virus, Prunus necrotic ringspot virus, Cucumber mosaic virus and Cowpea mosaic virus. We have analysed the capacity of the heterologous MPs to systemically transport the corresponding chimeric AMV genome. All MPs were competent in systemic transport but required the fusion at their C terminus of the coat protein-interacting C-terminal 44 aa (A44) of the AMV MP. Except for the TMV MP, the presence of the hybrid virus in upper leaves correlated with the capacity to move locally. These results suggest that all the MPs assigned to the 30K superfamily should be exchangeable not only for local virus movement but also for systemic transport when the A44 fragment is present.
Knowledge, Attitude, and Practice of Dry Eye Treatment by Institutional Chinese Physicians in Singapore
Authors: Lan Wanwen , Lee Sze Yee , Lee Man Xin , Tong Louis
Published: November 2012

Dry eye is a common health problem worldwide, causing significant discomfort and inconvenience to sufferers. The conventional treatment of dry eye via topical administration of eye drops is deemed palliative and unsatisfactory to many. Traditional Chinese medicine (TCM) has shown some promise in dry eye treatment; however, the extent of its use and acceptance is uncertain. We evaluated the knowledge, attitude, and practice of institutional TCM practitioners in the treatment of dry eye in Singapore. A questionnaire was generated to address the study aims and sent to TCM practitioners listed in the Singapore TCM practitioners’ board database. About three quarters of respondents thought that dry eye was not severe enough to be a public health burden but most thought that TCM was effective in the treatment of dry eye. Acupuncture and herbal medicine were most commonly used TCM modalities in dry eye treatment, and a single TCM treatment session would be charged S$20–50 by the practitioner. The majority of surveyed institutional TCM practitioners in Singapore believe that TCM is relevant in dry eye treatment. Public awareness should be raised regarding the availability of TCM as alternative medicine for dry eye.
Rhizobial and Mycorrhizal Symbioses in Lotus japonicus Require Lectin Nucleotide Phosphohydrolase, Which Acts Upstream of Calcium Signaling
Authors: Roberts Nicholas J. , Morieri Giulia , Kalsi Gurpreet , Rose Alan , Stiller Jiri , Edwards Anne , Xie Fang , Gresshoff Peter M. , Oldroyd Giles E.D. , Downie J. Allan , Etzler Marilynn E.
Published: November 2012

Nodulation in legumes requires the recognition of rhizobially made Nod factors. Genetic studies have revealed that the perception of Nod factors involves LysM domain receptor-like kinases, while biochemical approaches have identified LECTIN NUCLEOTIDE PHOSPHOHYDROLASE (LNP) as a Nod factor-binding protein. Here, we show that antisense inhibition of LNP blocks nodulation in Lotus japonicus. This absence of nodulation was due to a defect in Nod factor signaling based on the observations that the early nodulation gene NODULE INCEPTION was not induced and that both Nod factor-induced perinuclear calcium spiking and calcium influx at the root hair tip were blocked. However, Nod factor did induce root hair deformation in the LNP antisense lines. LNP is also required for infection by the mycorrhizal fungus Glomus intraradices, suggesting that LNP plays a role in the common signaling pathway shared by the rhizobial and mycorrhizal symbioses. Taken together, these observations indicate that LNP acts at a novel position in the early stages of symbiosis signaling. We propose that LNP functions at the earliest stage of the common nodulation and mycorrhization symbiosis signaling pathway downstream of the Nod factor receptors; it may act either by influencing signaling via changes in external nucleotides or in conjunction with the LysM receptor-like kinases for recognition of Nod factor.
Potassium salts of hypodiphosphoric acid
Authors: Szafranowska Barbara , Ślepokura Katarzyna , Lis Tadeusz
Published: November 2012

The synthesis and crystal structures of a series of six crystalline potassium salts of hypodiphosphoric acid, H4P2O6, are reported, namely potassium hydrogen phosphonophosphonate, K+·H3P2O6−, (I), dipotassium dihydrogen hypodiphosphate monohydrate, 2K+·H2P2O62−·H2O, (II), dipotassium dihydrogen hypodiphosphate dihydrate, 2K+·H2P2O62−·2H2O, (III), pentapotassium hydrogen hypodiphosphate dihydrogen hypodiphosphate dihydrate, 5K+·HP2O63−·H2P2O62−·2H2O, (IV), tripotassium hydrogen hypodiphosphate tetrahydrate, 3K+·HP2O63−·4H2O, (V), and tetrapotassium hypodiphosphate tetrahydrate, 4K+·P2O64−·4H2O, (VI). All the hypodiphosphate anions,viz.H3P2O6−, H2P2O62−, HP2O63−and P2O64−, adopt a staggered conformation. The P—P bond lengths [2.1722 (7)–2.1892 (10) Å] do not depend on the basicity of the anion. The compounds are organized into different types of one-, two- or three-dimensional polymeric hydrogen-bonded networks, or simply exist in the form of isolated or dimeric units. The coordination numbers of the K+cations range from 6 to 9, and the cationic sublattices are polymeric one-, two- or three-dimensional networks, or isolated [KO6] or dimeric [K2O12] polyhedra.
Oxidation of a dinuclear manganese(II) complex to an oxide-bridged dimanganese(IV) complex
Authors: Lennartson Anders , McKenzie Christine J.
Published: November 2012

Bis{μ-2-[bis(pyridin-2-ylmethyl)amino]acetato}bis[diaquamanganese(II)] bis(trifluoromethanesulfonate) monohydrate, [Mn2(C14H14N3O2)2(H2O)4](CF3O3S)2·H2O, (I), and bis{μ-3-[bis(pyridin-2-ylmethyl)amino]propionato}bis[aquamanganese(II)] bis(trifluoromethanesulfonate) dihydrate, [Mn2(C15H16N3O2)2(H2O)2](CF3O3S)2·2H2O, (II), form binuclear seven-coordinate complexes. Oxidation of (II) with ammonium hexanitratocerate(IV), (NH4)2[Ce(NO3)6], gave the oxide-bridged dimanganese(IV) complex di-μ-oxido-bis(bis{3-[bis(pyridin-2-ylmethyl)amino]propionato}manganese(IV)) bis[triaquatetranitratocerate(IV)], [Mn2O2(C15H16N3O2)2][Ce(NO3)4(H2O)3]2, (III). The manganese complexes in (II) and (III) sit on a site of \overline{1} symmetry.
Regulatory effects of Spirulina complex polysaccharides on growth of murine RSV‐M glioma cells through Toll‐like receptor 4
Authors: Kawanishi Yu , Tominaga Akira , Okuyama Hiromi , Fukuoka Satoshi , Taguchi Takahiro , Kusumoto Yutaka , Yawata Toshio , Fujimoto Yasunori , Ono Shiro , Shimizu Keiji
Published: November 2012

This study is the first to report that Spirulina complex polysaccharides (CPS) suppress glioma growth by down‐regulating angiogenesis via a Toll‐like receptor 4 signal. Murine RSV‐M glioma cells were implanted s.c. into C3H/HeN mice and TLR4 mutant C3H/HeJ mice. Treatment with either Spirulina CPS or Escherichia coli (E. coli) lipopolysaccharides (LPS) strongly suppressed RSV‐M glioma cell growth in C3H/HeN, but not C3H/HeJ, mice. Glioma cells stimulated production of interleukin (IL)‐17 in both C3H/HeN and C3H/HeJ tumor‐bearing mice. Treatment with E. coli LPS induced much greater IL‐17 production in tumor‐bearing C3H/HeN mice than in tumor‐bearing C3H/HeJ mice. In C3H/HeN mice, treatment with Spirulina CPS suppressed growth of re‐transplanted glioma; however, treatment with E. coli LPS did not, suggesting that Spirulina CPS enhance the immune response. Administration of anti‐cluster of differentiation (CD)8, anti‐CD4, anti‐CD8 antibodies, and anti‐asialo GM1 antibodies enhanced tumor growth, suggesting that T cells and natural killer cells or macrophages are involved in suppression of tumor growth by Spirulina CPS. Although anti‐interferon‐γ antibodies had no effect on glioma cell growth, anti‐IL‐17 antibodies administered four days after tumor transplantation suppressed growth similarly to treatment with Spirulina CPS. Less angiogenesis was observed in gliomas from Spirulina CPS‐treated mice than in those from saline‐ or E. coli LPS‐treated mice. These findings suggest that, in C3H/HeN mice, Spirulina CPS antagonize glioma cell growth by down‐regulating angiogenesis, and that this down‐regulation is mediated in part by regulating IL‐17 production.
Mental Illness, Access to Hospitals with Invasive Cardiac Services, and Receipt of Cardiac Procedures by Medicare Acute Myocardial Infarction Patients
Authors: Li Yue , Glance Laurent G. , Lyness Jeffrey M. , Cram Peter , Cai Xueya , Mukamel Dana B.
Published: November 2012

Objective

Older persons with coronary heart disease have reduced access to appropriate medical and surgical services if they are also mentally ill. This study determined whether difference exists in access to hospitals that provide on‐site invasive cardiac procedures among a national cohort of Medicare acute myocardial infarction (AMI) patients with and without comorbid mental illness, and its implications for subsequent procedure use.

Methods

Retrospective analyses of Medicare claims for initial AMI admissions between January and September 2007. Hospital service availability was obtained from annual survey data. Logistic regression estimated the associations of mental illness with admission to hospitals with any invasive cardiac services (diagnostic catheterization, coronary angioplasty, or bypass surgery) and post‐admission care patterns and outcomes.

Results

Eighty‐two percent of mentally ill AMI patients (n = 28,888) versus 87 percent of other AMI patients (n = 73,895) were initially admitted to hospitals with invasive cardiac facilities [adjusted odds ratio (OR) = 0.81, p < .001]. Admission to such hospitals was associated with overall higher rate of procedure use within 90 days of admission and improved 30‐days readmission and mortality rates. However, irrespective of on‐site service availability of the admitting hospital, mentally ill patients were one half as likely to receive invasive procedures (adjusted OR approximately 0.5, p < .001).

Conclusions

Among Medicare patients with AMI, those with comorbid mental illness were less likely to be admitted to hospitals with on‐site invasive cardiac services. Mental illness was associated with reduced cardiac procedure use within each type of admitting hospitals (with on‐site invasive cardiac services or not).
Stress response to acoustic stimuli in an aphid: A behavioral bioassay model
Authors: Lee Yerim , Kim Hyojoong , Kang Taek‐Jun , Jang Yikweon
Published: November 2012

The green peach aphid, Myzus persicae (Sulzer), feeds consistently and regularly throughout all stages of nymphs and adult. That is, honey dew production, which indicates a state of feeding, occurs at regular intervals within a given stage, and moving, which interrupts feeding, tends to occur rarely. We used these behaviors to test whether sound stimuli acted as a stress in this species. We conducted the playback experiment in which acoustic stimuli with a combination of five frequencies (100, 500, 1000, 5000, and 10000 Hz) and three intensity levels (66, 78, 90 dB SPL) were presented to all stages of aphids. Under all acoustic stimuli, honey dew production occurred less often, and moving occurred more often and for longer. The results of two‐way multivariate analysis of variance showed that the stimulus frequency was a significant factor for variation in aphid behaviors in the playback experiment. However, there was no intensity effect on the aphid's behavior. Based on the electrical penetration graph experiment, aphid feeding stopped frequently and lasted only for short durations under acoustic stimuli. The results of both experiments demonstrated that the acoustic stimuli were effective in inducing feeding suppression in this species. Thus, the acoustic stimuli may be a stressor in the green peach aphid. Furthermore, the behavioral bioassay employed in this study may be used to assess the effect of various stressors on aphids.
Improving PCR detection of prey in molecular diet studies: importance of group‐specific primer set selection and extraction protocol performances
Authors: Zarzoso‐Lacoste Diane , Corse Emmanuel , Vidal Eric
Published: November 2012

While the morphological identification of prey remains in predators' faeces is the most commonly used method to study trophic interactions, many studies indicate that this method does not detect all consumed prey. Polymerase chain reaction–based methods are increasingly used to detect prey DNA in the predator food bolus and have proven efficient, delivering highly accurate results. When studying complex diet samples, the extraction of total DNA is a critical step, as polymerase chain reaction (PCR) inhibitors may be co‐extracted. Another critical step involves a careful selection of suitable group‐specific primer sets that should only amplify DNA from the targeted prey taxon. In this study, the food boluses of five Rattus rattus and seven Rattus exulans were analysed using both morphological and molecular methods. We tested a panel of 31 PCR primer pairs targeting bird, invertebrate and plant sequences; four of them were selected to be used as group‐specific primer pairs in PCR protocols. The performances of four DNA extraction protocols (QIAamp® DNA stool mini kit, DNeasy® mericon food kit and two of cetyltrimethylammonium bromide‐based methods) were compared using four variables: DNA concentration, A260/A280 absorbance ratio, food compartment analysed (stomach or faecal contents) and total number of prey‐specific PCR amplification per sample. Our results clearly indicate that the A260/A280 absorbance ratio, which varies between extraction protocols, is positively correlated to the number of PCR amplifications of each prey taxon. We recommend using the DNeasy® mericon food kit (QIAGEN), which yielded results very similar to those achieved with the morphological approach.
Two highly validated SSR multiplexes (8‐plex) for Euphrates' poplar, Populus euphratica (Salicaceae)
Authors: Xu Fang , Feng Sisi , Wu Rongling , Du Fang K.
Published: November 2012

Multiplex PCR amplification of microsatellites has significantly increased the throughput and decreased the costs of genotyping. We have developed two highly polymorphic microsatellite multiplexes for Populus euphratica, the only tree species found in desert regions of Western China and adjacent Central Asian countries. The first of these multiplex kits comprises an eight‐Plex of genomic SSRs (gSSRs) obtained from published databases. The second comprises an eight‐plex of newly designed EST‐SSRs (eSSRs) based on expressed sequence tags for P. euphratica. Both kits were tested on a sample of 170 individuals from four populations. The gSSRs exhibited slightly more polymorphism than the eSSRs. The new multiplex protocols yielded consistent results in the hands of multiple researchers, demonstrating their robustness. The 16 loci used in the kits exhibited a high transferability rate (82.0%) in eight other poplar species belonging to five different sections of the genus. Both kits should therefore be useful for further investigations of population genetics in P. euphratica and related species. Our results indicate that it is essential to follow recently established recommendations when developing microsatellite markers, including verifying the amplification efficiency, detecting null alleles and carefully measuring error rates.
Discussion of Corporate Governance Reform and Executive Incentives: Implications for Investments and Risk Taking
Authors: Selto Frank H. , Cussatt Marc
Published: November 2012

We discuss the strengths and weaknesses of the article by Cohen, Dey and Lys (CDL). Strengths include persuasive theoretical arguments for impacts of the Sarbanes Oxley Act (SOX) on corporate investment strategies and for several mechanisms through which firms influence changes in risky investments. CDL also provides intriguing opportunities for learning about impacts of external regulatory events and for enriching management accounting research and classroom discussions of management control. Weaknesses include (1) narrow scope, perhaps driven by archival data availability; (2) difficulties in implementing the research design and method; (3) possible bias of incentive and investment measures; (4) incomplete estimates of the effect of SOX on compensation, incentives, and investments; and (5) questionable control of endogeneity. We offer recommendations from extant literature to mitigate these weaknesses in future research.