bluuebunny/crossref_metadata_2025 huggingface dataset:
Aldehyde Dehydrogenase 2 Deficiency Ameliorates Alcoholic Fatty Liver but Worsens Liver Inflammation and Fibrosis in Mice
Authors: Kwon Hyo-Jung , Won Young-Suk , Park Ogyi , Chang Binxia , Duryee Michael J. , Thiele Geoffrey E. , Matsumoto Akiko , Singh Surendra , Abdelmegeed Mohamed A. , Song Byoung-Joon , Kawamoto Toshihiro , Vasiliou Vasilis , Thiele Geoffrey M. , Gao Bin
Published: February 2014

Aldehyde dehydrogenase 2 (ALDH2) is the major enzyme that metabolizes acetaldehyde produced from alcohol metabolism. Approximately 40-50% of East Asians carry an inactive ALDH2 gene and exhibit acetaldehyde accumulation after alcohol consumption. However, the role of ALDH2 deficiency in the pathogenesis of alcoholic liver injury remains obscure. In the present study, wild-type and ALDH2−/− mice were subjected to ethanol feeding and/or carbon tetrachloride (CCl4) treatment, and liver injury was assessed. Compared with wild-type mice, ethanol-fed ALDH2−/− mice had higher levels of malondialdehyde-acetaldehyde (MAA) adduct and greater hepatic inflammation, with higher hepatic interleukin (IL)-6 expression but surprisingly lower levels of steatosis and serum alanine aminotransferase (ALT). Higher IL-6 levels were also detected in ethanol-treated precision-cut liver slices from ALDH2−/− mice and in Kupffer cells isolated from ethanol-fed ALDH2−/− mice than those levels in wild-type mice.

In vitro

incubation with MAA enhanced the lipopolysaccharide (LPS)-mediated stimulation of IL-6 production in Kupffer cells. In agreement with these findings, hepatic activation of the major IL-6 downstream signaling molecule signal transducer and activator of transcription 3 (STAT3) was higher in ethanol-fed ALDH2−/− mice than in wild-type mice. An additional deletion of hepatic STAT3 increased steatosis and hepatocellular damage in ALDH2−/− mice. Finally, ethanol-fed ALDH2−/− mice were more prone to CCl4-induced liver inflammation and fibrosis than ethanol-fed wild-type mice.

Conclusion :

ALDH2−/− mice are resistant to ethanol-induced steatosis but prone to inflammation and fibrosis by way of MAA-mediated paracrine activation of IL-6 in Kupffer cells. These findings suggest that alcohol, by way of acetaldehyde and its associated adducts, stimulates hepatic inflammation and fibrosis independent from causing hepatocyte death, and that ALDH2-deficient individuals may be resistant to steatosis and blood ALT elevation, but are prone to liver inflammation and fibrosis following alcohol consumption. (Hepatology 2014;60:146–157)
Long noncoding RNA in liver diseases
Authors: Takahashi Kenji , Yan Irene , Haga Hiroaki , Patel Tushar
Published: February 2014

The identification of the presence of large RNA transcripts that do not code for proteins but that may have biological functions has provided an important new perspective in gene regulation. These long noncoding RNAs (lncRNAs) are being increasingly recognized to contribute to many biological processes through diverse mechanisms. The roles of these emerging genes are being recognized across kingdoms. These findings are profoundly altering our understanding of disease pathobiology and leading to the emergence of new biological concepts underlying human diseases. Strategies for the discovery and characterization of lncRNAs are highlighted. Several lncRNAs have been described in liver disease, and in liver cancers in particular. Their molecular mechanisms of action, function, and contributions to disease pathophysiology are reviewed. LncRNA genes associated with liver diseases have potential roles as biomarkers of disease diagnosis, prognosis, or therapeutic response as well as direct targets for therapeutic intervention. Conclusion: The emerging knowledge in this rapidly advancing field offers promise for new fundamental knowledge and clinical applications that will be relevant for human liver diseases. (Hepatology 2014;60:744–753)
Ring1B Promotes Hepatic Stem/Progenitor Cell Expansion Through Simultaneous Suppression of Cdkn1a and Cdkn2a in Mice
Authors: Koike Hiroyuki , Ueno Yasuharu , Naito Takako , Shiina Tomoya , Nakata Susumu , Ouchi Rie , Obana Yuta , Sekine Keisuke , Zheng Yun-Wen , Takebe Takanori , Isono Kyo-ichi , Koseki Haruhiko , Taniguchi Hideki
Published: February 2014

Polycomb-group (PcG) proteins play crucial roles in self-renewal of stem cells by suppressing a host of genes through histone modifications. Identification of the downstream genes of PcG proteins is essential for elucidation of the molecular mechanisms of stem cell self-renewal. However, little is known about the PcG target genes in tissue stem cells. We found that the PcG protein, Ring1B, which regulates expression of various genes through monoubiquitination of histone H2AK119, is essential for expansion of hepatic stem/progenitor cells. In mouse embryos with a conditional knockout of

Ring1B

, we found that the lack of Ring1B inhibited proliferation and differentiation of hepatic stem/progenitor cells and thereby inhibited hepatic organogenesis. These events were characterized by derepression of cyclin-dependent kinase inhibitors (CDKIs) Cdkn1a and Cdkn2a, known negative regulators of cell proliferation. We conducted clonal culture experiments with hepatic stem/progenitor cells to investigate the individual genetic functions of

Ring1B

,

Cdkn1a

, and

Cdkn2a

. The data showed that the cell-cycle inhibition caused by Ring1B depletion was reversed when

Cdkn1a

and

Cdkn2a

were suppressed simultaneously, but not when they were suppressed individually.

Conclusion :

Our results show that expansion of hepatic stem/progenitor cells requires Ring1B-mediated epigenetic silencing of

Cdkn1a

and

Cdkn2a

, demonstrating that Ring1B simultaneously regulates multiple CDKIs in tissue stem/progenitor cells. (Hepatology 2014;60:323-333)
Grid cell spatial tuning reduced following systemic muscarinic receptor blockade
Authors: Newman Ehren L. , Climer Jason R. , Hasselmo Michael E.
Published: February 2014

Grid cells of the medial entorhinal cortex exhibit a periodic and stable pattern of spatial tuning that may reflect the output of a path integration system. This grid pattern has been hypothesized to serve as a spatial coordinate system for navigation and memory function. The mechanisms underlying the generation of this characteristic tuning pattern remain poorly understood. Systemic administration of the muscarinic antagonist scopolamine flattens the typically positive correlation between running speed and entorhinal theta frequency in rats. The loss of this neural correlate of velocity, an important signal for the calculation of path integration, raises the question of what influence scopolamine has on the grid cell tuning as a read out of the path integration system. To test this, the spatial tuning properties of grid cells were compared before and after systemic administration of scopolamine as rats completed laps on a circle track for food rewards. The results show that the spatial tuning of the grid cells was reduced following scopolamine administration. The tuning of head direction cells, in contrast, was not reduced by scopolamine. This is the first report to demonstrate a link between cholinergic function and grid cell tuning. This work suggests that the loss of tuning in the grid cell network may underlie the navigational disorientation observed in Alzheimer's patients and elderly individuals with reduced cholinergic tone. © 2014 Wiley Periodicals, Inc.
Is the DPT tautomerization of the long A·G Watson–Crick DNA base mispair a source of the adenine and guanine mutagenic tautomers? A QM and QTAIM response to the biologically important question
Authors: Brovarets' Ol'ha O. , Zhurakivsky Roman O. , Hovorun Dmytro M.
Published: February 2014

Herein, we first address the question posed in the title by establishing the tautomerization trajectoryviathe double proton transfer of the adenine·guanine (A·G) DNA base mispair formed by the canonical tautomers of the A and G bases into the A*·G* DNA base mispair, involving mutagenic tautomers, with the use of the quantum‐mechanical calculations and quantum theory of atoms in molecules (QTAIM). It was detected that the A·G ↔ A*·G* tautomerization proceeds through the asynchronous concerted mechanism. It was revealed that the A·G base mispair is stabilized by the N6H···O6 (5.68) and N1H···N1 (6.51) hydrogen bonds (H‐bonds) and the N2H···HC2 dihydrogen bond (DH‐bond) (0.68 kcal·mol−1), whereas the A*·G* base mispair—by the O6H···N6 (10.88), N1H···N1 (7.01) and C2H···N2 H‐bonds (0.42 kcal·mol−1). The N2H···HC2 DH‐bond smoothly and without bifurcation transforms into the C2H···N2 H‐bond at the IRC = −10.07 Bohr in the course of the A·G ↔ A*·G* tautomerization. Using the sweeps of the energies of the intermolecular H‐bonds, it was observed that the N6H···O6 H‐bond is anticooperative to the two others—N1H···N1 and N2H···HC2 in the A·G base mispair, while the latters are significantly cooperative, mutually strengthening each other. In opposite, all three O6H···N6, N1H···N1, and C2H···N2 H‐bonds are cooperative in the A*·G* base mispair. All in all, we established the dynamical instability of the А*·G* base mispair with a short lifetime (4.83·10−14s), enabling it not to be deemed feasible source of the A* and G* mutagenic tautomers of the DNA bases. The small lifetime of the А*·G* base mispair is predetermined by the negative value of the Gibbs free energy for the A*·G* → A·G transition. Moreover, all of the six low‐frequency intermolecular vibrations cannot develop during this lifetime that additionally confirms the aforementioned results. Thus, the A*·G* base mispair cannot be considered as a source of the mutagenic tautomers of the DNA bases, as the A·G base mispair dissociates during DNA replication exceptionally into the A and G monomers in the canonical tautomeric form. © 2013 Wiley Periodicals, Inc.
Recent advances in chelator design and labelling methodology for 68Ga radiopharmaceuticals
Authors: Burke Benjamin P. , Clemente Gonçalo S. , Archibald Stephen J.
Published: February 2014

Gallium‐68 has the potential to become the technetium‐99m of positron emission tomography with ideal decay characteristics and a long‐lived parent isotope for generator production. The work in the area of 68Ga is focused on two key areas: (1) synthesis of a library of bifunctional chelators, which can be quickly radiolabelled to form kinetically inert complexes under mild conditions compatible with biomolecules and (2) development of radiosynthetic methodologies for clinical use and to facilitate radiolabelling of a wide range of chelators under mild conditions. Recent advances in these areas, with particular focus on the past 3 years, are covered herein.
Design, Operation, and Safety of Single‐Room Interventional MRI Suites: Practical Experience From Two Centers
Authors: White Mark J. , Thornton John S. , Hawkes David J. , Hill Derek L.G. , Kitchen Neil , Mancini Laura , McEvoy Andrew W. , Razavi Reza , Wilson Sally , Yousry Tarek , Keevil Stephen F.
Published: February 2014

The design and operation of a facility in which a magnetic resonance imaging (MRI) scanner is incorporated into a room used for surgical or endovascular cardiac interventions presents several challenges. MR safety must be maintained in the presence of a much wider variety of equipment than is found in a diagnostic unit, and of staff unfamiliar with the MRI environment, without compromising the safety and practicality of the interventional procedure. Both the MR‐guided cardiac interventional unit at Kings College London and the intraoperative imaging suite at the National Hospital for Neurology and Neurosurgery are single‐room interventional facilities incorporating 1.5 T cylindrical‐bore MRI scanners. The two units employ similar strategies to maintain MR safety, both in original design and day‐to‐day operational workflows, and between them over a decade of incident‐free practice has been accumulated. This article outlines these strategies, highlighting both similarities and differences between the units, as well as some lessons learned and resulting procedural changes made in both units since installation. J. Magn. Reson. Imaging 2015;41:34–43. © 2014 Wiley Periodicals, Inc.
Effects of formulation, extrusion cooking conditions, and CO2 injection on the formation of acrylamide in corn extrudates
Authors: Masatcioglu Mustafa Tugrul , Gokmen Vural , Ng Perry K W , Koksel Hamit
Published: February 2014

BACKGROUND

Acrylamide is a possible carcinogen and known to form in heat‐treated carbohydrate‐rich foods. This study was designed to investigate the effects of different ingredients (reducing sugars, chemical leavening agents, citric acid), processing conditions (feed moisture content: 22, 24 or 26%, exit die temperature: 110, 150 °C), and extrusion cooking methods (with or without CO2 injection) on acrylamide formation.

RESULTS

The type of reducing sugar did not have a considerable effect on acrylamide formation, while increased exit die temperature had a promoting effect. Addition of chemical leavening agents (sodium bicarbonate and ammonium bicarbonate) into formulations increased acrylamide formation levels. The addition of citric acid prevented acrylamide formation, but its effect on textural properties was detrimental. Acrylamide levels of extrudates decreased gradually with increasing feed moisture in all formulations. Acrylamide content of extrudates produced with 22% feed moisture decreased by 61% in the CO2 injection method compared to conventional extrusion. Furthermore, an 82% decrease in acrylamide content was observed with the combined effect of CO2 injection and increasing feed moisture content from 22 to 24% and decreased below the limit of quantification with a further increase in feed moisture.

CONCLUSION

A substantial decrease in final acrylamide level is probably due to restriction of two major steps of acrylamide formation: dehydration and decarboxylation. © 2014 Society of Chemical Industry
Effects of processing on mycotoxin stability in cereals
Authors: Milani Jafar , Maleki Gisoo
Published: February 2014

The mycotoxins that generally occur in cereals and other products are not completely destroyed during food‐processing operations and can contaminate finished processed foods. The mycotoxins most usually associated with cereal grains are aflatoxins, ochratoxins, deoxynivalenol, zearalenone and fumonisins. The various food processes that may have effects on mycotoxins include cleaning, milling, brewing, cooking, baking, frying, roasting, flaking, alkaline cooking, nixtamalization, and extrusion. Most of the food processes have variable effects on mycotoxins, with those that utilize high temperatures having the greatest effects. In general, the processes reduce mycotoxin concentrations significantly, but do not eliminate them completely. This review focuses on the effects of various thermal treatments on mycotoxins. © 2014 Society of Chemical Industry
Recovery of wolverines in the Western United States: Recent extirpation and recolonization or range retraction and expansion?
Authors: Mckelvey Kevin S. , Aubry Keith B. , Anderson Neil J. , Clevenger Anthony P. , Copeland Jeffrey P. , Heinemeyer Kimberley S. , Inman Robert M. , Squires John R. , Waller John S. , Pilgrim Kristine L. , Schwartz Michael K.
Published: February 2014

Wolverines were greatly reduced in number and possibly extirpated from the contiguous United States (U.S.) by the early 1900s. Wolverines currently occupy much of their historical range in Washington, Idaho, Montana, and Wyoming, but are absent from Utah and only single individuals are known to occur in California and Colorado. In response, the translocation of wolverines to California and Colorado is being considered. If wolverines are to be reintroduced, managers must identify appropriate source populations based on the genetic affinities of historical and modern wolverine populations. We amplified the mitochondrial control region of 13 museum specimens dating from the late 1800s to early 1900s and 209 wolverines from modern populations in the contiguous U.S. and Canada and combined results with previously published haplotypes. Collectively, these data indicated that historical wolverine populations in the contiguous U.S. were extirpated by the early 20th century, and that modern populations in the contiguous U.S. are likely the descendants of recent immigrants from the north. The Cali1 haplotype previously identified in California museum specimens was also common in historical samples from the southern Rocky Mountains, and likely evolved in isolation in the southern ice‐free refugium that encompassed most of the contiguous U.S. during the last glaciation. However, when southern populations were extirpated, these matrilines were eliminated. Several of the other haplotypes found in historical specimens from the contiguous U.S. also occur in modern North American populations, and belong to a group of haplotypes that are associated with the rapid expansion of northern wolverine populations after the last glacial retreat. Modern wolverines in the contiguous U.S. are primarily haplotype A, which is the most common and widespread haplotype in Canada and Alaska. For the translocation of wolverines to California, Colorado, and other areas in the western U.S., potential source populations in the Canadian Rocky Mountains may provide the best mix of genetic diversity and appropriate learned behavior. © 2014 The Wildlife Society.
The impact of fencing on the distribution of Przewalski's gazelle
Authors: Zhang Lu , Liu Jiazi , Mcshea William J. , Wu Yonglin , Wang Dajun , Lü Zhi
Published: February 2014

The endangered Przewalski's gazelle (Procapra przewalskii) experienced severe habitat loss and population decline over the last century. Illegal hunting of gazelles has been largely prevented since 2002, leaving fencing of pastures as one of the main threats to the gazelle. We conducted surveys on 810 km of parallel transects on 8 gazelle‐occupied sites and 4 nearby control sites where no gazelles were found, and evaluated the impact of fencing on gazelle distribution. A comparison of gazelle‐occupied and control sites showed the former had a lower fence density and height, lower aboveground biomass (EVI), and a longer distance to houses. Logistic regression indicated that the presence of gazelle feces on the 1‐km segment of transect was negatively affected by the density of fences and the proportion of fences with barbed wire both in spring and summer. In addition, we found a negative effect from distance to houses in spring and from EVI in summer. Gazelles did not occur more on grasslands with greater vegetation biomass, possibly because of the association of greater vegetation biomass with greater fence density and proportion of barbed wires. Although removing fences can be costly, lowering the top barbed wire, as well as constructing special gates and seasonal use of existing gates, may be beneficial for this endangered species at minimal disruption to local people. © 2014 The Wildlife Society.
Evidence for a right cochlear implant advantage in simultaneous bilateral cochlear implantation
Authors: Henkin Yael , Swead Riki Taitelbaum , Roth Daphne Ari‐Even , Kishon‐Rabin Liat , Shapira Yisgav , Migirov Lela , Hildesheimer Minka , Kaplan‐Neeman Ricky
Published: February 2014

Objectives/Hypothesis

To compare speech perception performance with right versus left cochlear implants (CIs) in children with bilateral CIs implanted simultaneously.

Study Design

Prospective case series of patients undergoing simultaneous bilateral cochlear implantation.

Methods

Speech perception performance was tested in 10, right‐handed children who received bilateral CIs simultaneously between 11 and 36 months (mean, 21 months), had at least 18 months of bilateral CI use, and were 5.3 years of age during testing. All children exhibited bilateral symmetrical severe‐to‐profound hearing loss prior to implantation and did not benefit from hearing aids. Speech perception performance was evaluated with the right CI and the left CI by means of an open‐set monosyllabic word test in quiet presented at 45 dB HL in a sound field.

Results

All children exhibited higher performance with the right CI compared to the left CI. Group mean performance with the right CI was 66.5% compared to 52% with the left CI (P = .002), yielding a 14.5% difference. With increasing duration of bilateral CI use and age at evaluation, the right–left difference increased (r = 0.72, P = .019 and r = 0.74, P = .014, respectively).

Conclusions

Current preliminary data indicate that children with bilateral CIs implanted simultaneously exhibit a significant right ear advantage for speech. Similarly to reports on normal‐hearing children, right ear preference for speech increased with increasing age and auditory–linguistic experience. Thus, simultaneous bilateral cochlear implantation may lead to normal development of auditory pathways and may be an important contributor to the superior auditory, language, and communication skills reported in children with bilateral versus unilateral CIs.

Level of Evidence

4. Laryngoscope, 124:1937–1941, 2014
A Political Ecology Perspective of Land Degradation in the North Ethiopian Highlands
Authors: Lanckriet Sil , Derudder Ben , Naudts Jozef , Bauer Hans , Deckers Jozef , Haile Mitiku , Nyssen Jan
Published: February 2014

Severe environmental degradation in the north Ethiopian Highlands is among others the result of mismanagement, overpopulation and droughts. However, here, we investigate the linkages of land degradation with the historical dynamics of the political–ecological system and regional land policies. We performed semi‐structured interviews with 93 farmers in eight villages in the Tigray region (north Ethiopia) and conceptualised a political–ecological model of land tenure and degradation changes for the region. Results show that different land policies caused and still cause land degradation in several ways. Interviews reveal that the unequal character of land rights during feudal times played an important role in 19th and 20th century land degradation. In particular, poor farmers were forced to construct their farms on marginal terrains, such as steep slopes in dry areas and marshes in cold and humid areas, increasing the catchment water runoff and degradation. The interviews further suggest that after the Derg regime (1974–1991), environmental conservation strategies were successfully implemented at larger scales. Overall, feudal, Derg and contemporary land policies have all had impacts on environmental degradation and have left their fingerprints on the physical landscape of northern Ethiopia. Copyright © 2014 John Wiley & Sons, Ltd.
Formal continuity implies uniform continuity near compact images on metric spaces
Authors: Palmgren Erik
Published: February 2014

The localic completion of a metric space induces a canonical notion of continuous map between metric spaces. It is shown that these maps are continuous in the sense of Bishop constructive mathematics, i.e., uniformly continuous near every compact image.
Dual Redox and Thermoresponsive Double Hydrophilic Block Copolymers with Tunable Thermoresponsive Properties and Self‐Assembly Behavior
Authors: Chan Nicky , An So Young , Yee Nathan , Oh Jung Kwon
Published: February 2014

The synthesis, tunable thermoresponsive properties, and self‐assembly of dual redox and thermoresponsive double hydrophilic block copolymers having pendant disulfide linkages (DHBCss) are reported. Well‐defined DHBCss composed of a hydrophilic poly(ethylene oxide) block and a dual thermo‐ and reduction‐responsive random copolymer block containing pendant disulfide linkages are synthesized by atom transfer radical polymerization. Their lower critical solution temperature (LCST) transitions are adjusted through modulating pendant hydrophobic–hydrophilic balance with disulfide–thiol–sulfide chemistry. Further, these DHBCss derivatives are converted to disulfide‐crosslinked nanogels at temperatures above LCST through temperature‐driven self‐assembly and in situ disulfide crosslinking. They exhibit enhanced colloidal stability and further reduction‐responsive degradability, thus demonstrating versatility of dual thermo‐ and reduction‐responsive smart materials.

image
Controlled Polymerization of Protic Ionic Liquid Monomer by ARGET‐ATRP and TERP
Authors: Nakamura Yasuyuki , Nakanishi Kouji , Yamago Shigeru , Tsujii Yoshinobu , Takahashi Kenichi , Morinaga Takashi , Sato Takaya
Published: February 2014

The direct synthesis of structurally well‐defined protic polymeric ionic liquid (PIL) with controlled molecular weight and molecular weight distribution is examined using N,N‐diethyl‐N‐(2‐methacryloylethyl) ammonium bis(tri‐fluoromethylsulfonyl)imide (DEMH‐TFSI) as a monomer. Three polymerization methods, namely, atom transfer radical polymerization (ATRP), activators regenerated by electron transfer (ARGET)‐ATRP, and organotellurium‐mediated living radical polymerization (TERP) are employed in this study. While the polymerization by ATRP is slow and does not reach high monomer conversion that under ARGET‐ATRP and TERP proceeds smoothly and affords structurally well‐defined poly(DEMH‐TFSI)s. TERP is especially efficient for the control and poly(DEMH‐TFSI)s with low to high molecular weights ( = 49 100–392 500) and narrow molecular weight distributions (/ = 1.17–1.46) are obtained. These results represent the first example of synthesis of a structurally well‐defined protic, ammonium PIL by direct polymerization of the protic ionic liquid monomer. The polymerization of N,N‐diethyl‐N‐(2‐methacryloylethyl)‐N‐methylammonium bis(trifluoromethylsulfonyl)imide (DEMM‐TFSI), which possesses a quaternary ammonium salt, also proceeds in a highly controlled manner under TERP conditions. A diblock copolymer, polystyrene‐block‐poly(DEMH‐TFSI), is also successfully synthesized by TERP.

image
Novel α,α‐Bischolesteryl Functional (Co)Polymers: RAFT Radical Polymerization Synthesis and Preliminary Solution Characterization
Authors: Roth Peter J. , Davis Thomas P. , Lowe Andrew B.
Published: February 2014

Well‐defined poly[pentafluorophenyl (meth)acrylate] (PPFP(M)A) homopolymers are prepared by RAFT radical polymerization mediated by a novel chain transfer agent containing two cholesteryl groups in the R‐group fragment. Subsequent reaction with a series of small‐molecule amines in the presence of an appropriate Michael acceptor for ω‐group end‐capping yields a library of novel bischolesteryl functional hydrophilic homopolymers. Two examples of statistical copolymers are also prepared including a biologically relevant sugar derivative. Specific examples of these homopolymers are examined with respect to their ability to self assemble in aqueous media—a process driven entirely by the cholesteryl end groups. In all instances evaluated, and under the preparation conditions examined, the homopolymers aggregate clearly forming polymersomes spanning an impressive size range.

image
The representation of meromorphic solutions for a class of odd order algebraic differential equations and its applications
Authors: Huang Zifeng , Zhang Liming , Chen Qiuhui , Yuan Wenjun
Published: February 2014

In this paper, we employ the Nevanlinna's value distribution theory to investigate the existence of meromorphic solutions of algebraic differential equations. We obtain the representations of all meromorphic solutions for a class of odd order algebraic differential equations with the weak ⟨p,q⟩and dominant conditions. Moreover, we give the complex method to find all traveling wave exact solutions of corresponding partial differential equations. As an example, we obtain all meromorphic solutions of the Kuramoto–Sivashinsky equation by using our complex method. Our results show that the complex method provides a powerful mathematical tool for solving great many nonlinear partial differential equations in mathematical physics. Copyright © 2014 John Wiley & Sons, Ltd.
Blow‐up phenomena for a system of semilinear parabolic equations with nonlinear boundary conditions
Authors: Baghaei Khadijeh , Hesaaraki Mahmoud
Published: February 2014

This paper deals with the blow‐up phenomena for a system of parabolic equations with nonlinear boundary conditions. We show that under some conditions on the nonlinearities, blow‐up occurs at some finite time. We also obtain upper and lower bounds for the blow‐up time when blow‐up occurs. Copyright © 2014 John Wiley & Sons, Ltd.
Quantitative and qualitative 1H, 13C, and 15N NMR spectroscopic investigation of the urea–formaldehyde resin synthesis
Authors: Steinhof Oliver , Kibrik Éléonore J. , Scherr Günter , Hasse Hans
Published: February 2014

Urea–formaldehyde resins are bulk products of the chemical industry. Their synthesis involves a complex reaction network. The present work contributes to its elucidation by presenting results from detailed NMR spectroscopic studies with different methods. Besides1H NMR and13C NMR,15N NMR spectroscopy is also applied.15N‐enriched urea was used for the investigations. A detailed NMR signal assignment and a model of the reaction network of the hydroxymethylation step of the synthesis are presented. Because of its higher spectral dispersion and the fact that all key reactions directly involve the nitrogen centers,15N NMR provides a much larger amount of detail than do1H and13C NMR spectroscopy. Symmetric and asymmetric dimethylol urea can be clearly distinguished and separated from monomethylol urea, trimethylol urea, and methylene‐bridged urea. The existence of hemiformals of methylol urea is confirmed. 1,3,5‐Oxadiazinan‐4‐on (uron) and its derivatives were not found in the reaction mixtures investigated here but were prepared via alternative routes. The molar ratios of formaldehyde to urea were 1, 2, and 4, the pH values 7.5 and 8.5, and the reaction temperature 60 °C. Copyright © 2014 John Wiley & Sons, Ltd.
A subspace approach to high‐resolution spectroscopic imaging
Authors: Lam Fan , Liang Zhi‐Pei
Published: February 2014

Purpose

To accelerate spectroscopic imaging using sparse sampling of
‐space and subspace (or low‐rank) modeling to enable high‐resolution metabolic imaging with good signal‐to‐noise ratio.

Methods

The proposed method, called SPectroscopic Imaging by exploiting spatiospectral CorrElation, exploits a unique property known as partial separability of spectroscopic signals. This property indicates that high‐dimensional spectroscopic signals reside in a very low‐dimensional subspace and enables special data acquisition and image reconstruction strategies to be used to obtain high‐resolution spatiospectral distributions with good signal‐to‐noise ratio. More specifically, a hybrid chemical shift imaging/echo‐planar spectroscopic imaging pulse sequence is proposed for sparse sampling of
‐space, and a low‐rank model‐based algorithm is proposed for subspace estimation and image reconstruction from sparse data with the capability to incorporate prior information and field inhomogeneity correction.

Results

The performance of the proposed method has been evaluated using both computer simulations and phantom studies, which produced very encouraging results. For two‐dimensional spectroscopic imaging experiments on a metabolite phantom, a factor of 10 acceleration was achieved with a minimal loss in signal‐to‐noise ratio compared to the long chemical shift imaging experiments and with a significant gain in signal‐to‐noise ratio compared to the accelerated echo‐planar spectroscopic imaging experiments.

Conclusion

The proposed method, SPectroscopic Imaging by exploiting spatiospectral CorrElation, is able to significantly accelerate spectroscopic imaging experiments, making high‐resolution metabolic imaging possible. Magn Reson Med 71:1349–1357, 2014. © 2014 Wiley Periodicals, Inc.
Proton magnetic resonance spectroscopy of brain metabolic shifts induced by acute administration of 2‐deoxy‐d‐glucose and lipopolysaccharides
Authors: Moshkin Mikhail P. , Akulov Andrey E. , Petrovski Dmitriy V. , Saik Olga V. , Petrovskiy Evgeny D. , Savelov Andrey A. , Koptyug Igor V.
Published: February 2014

In vivo proton magnetic resonance spectroscopy (1H MRS) of outbred stock ICR male mice (originating from the Institute of Cancer Research) was used to study the brain (hippocampus) metabolic response to the pro‐inflammatory stimulus and to the acute deficiency of the available energy, which was confirmed by measuring the maximum oxygen consumption. Inhibition of glycolysis by means of an injection with 2‐deoxy‐d‐glucose (2DG) reduced the levels of gamma‐aminobutyric acid (GABA, p < 0.05, in comparison with control, least significant difference (LSD) test), N‐acetylaspartate (NAA, p < 0.05, LSD test) and choline compounds, and at the same time increased the levels of glutamate and glutamine. An opposite effect was found after injection with bacterial lipopolysaccharide (LPS) – a very common pro‐inflammatory inducer. An increase in the amounts of GABA, NAA and choline compounds in the brain occurred in mice treated with LPS. Different metabolic responses to the energy deficiency and the pro‐inflammatory stimuli can explain the contradictory results of the brain 1H MRS studies under neurodegenerative pathology, which is accompanied by both mitochondrial dysfunction and inflammation. The prevalence of the excitatory metabolites such as glutamate and glutamine in 2DG treated mice is in good agreement with excitation observed during temporary reduction of the available energy under acute hypoxia or starvation. In turn, LPS, as an inducer of the sickness behavior, which was manifested as depression, sleepiness, loss of appetite etc., shifts the brain metabolic pattern toward the prevalence of the inhibitory neurotransmitter GABA. Copyright © 2014 John Wiley & Sons, Ltd.
Different quantification algorithms may lead to different results: a comparison using proton MRS lipid signals
Authors: Mosconi E. , Sima D. M. , Osorio Garcia M. I. , Fontanella M. , Fiorini S. , Van Huffel S. , Marzola P.
Published: February 2014

Proton magnetic resonance spectroscopy (MRS) is a sensitive method for investigating the biochemical compounds in a tissue. The interpretation of the data relies on the quantification algorithms applied to MR spectra. Each of these algorithms has certain underlying assumptions and may allow one to incorporate prior knowledge, which could influence the quality of the fit. The most commonly considered types of prior knowledge include the line‐shape model (Lorentzian, Gaussian, Voigt), knowledge of the resonating frequencies, modeling of the baseline, constraints on the damping factors and phase, etc.

In this article, we study whether the statistical outcome of a biological investigation can be influenced by the quantification method used. We chose to study lipid signals because of their emerging role in the investigation of metabolic disorders. Lipid spectra, in particular, are characterized by peaks that are in most cases not Lorentzian, because measurements are often performed in difficult body locations, e.g. in visceral fats close to peristaltic movements in humans or very small areas close to different tissues in animals. This leads to spectra with several peak distortions.

Linear combination of Model spectra (LCModel), Advanced Method for Accurate Robust and Efficient Spectral fitting (AMARES), quantitation based on QUantum ESTimation (QUEST), Automated Quantification of Short Echo‐time MRS (AQSES)‐Lineshape and Integration were applied to simulated spectra, and area under the curve (AUC) values, which are proportional to the quantity of the resonating molecules in the tissue, were compared with true values. A comparison between techniques was also carried out on lipid signals from obese and lean Zucker rats, for which the polyunsaturation value expressed in white adipose tissue should be statistically different, as confirmed by high‐resolution NMR measurements (considered the gold standard) on the same animals. LCModel, AQSES‐Lineshape, QUEST and Integration gave the best results in at least one of the considered groups of simulated or in vivo lipid signals. These outcomes highlight the fact that quantification methods can influence the final result and its statistical significance. Copyright © 2014 John Wiley & Sons, Ltd.
Relationship of anthropometric indices to abdominal and total body fat in youth: Sex and race differences
Authors: Barreira Tiago V. , Broyles Stephanie T. , Gupta Alok K. , Katzmarzyk Peter T.
Published: February 2014

Objective

To determine the influence of sex and race on relationships between anthropometry (body mass index [BMI], waist circumference [WC], waist‐to‐height ratio [W/Ht]) and adiposity (fat mass [FM], abdominal subcutaneous [SAT] and visceral adipose tissue [VAT]) in African American and white youth.

Methods

The sample included 382 youth 5‐18 years of age. FM and abdominal adiposity were assessed using dual energy X‐ray absorptiometry and magnetic resonance imaging. Regression was used to examine sex and race effects in the relationship between independent (BMI, WC, and W/Ht) and dependent (FM, SAT and VAT) variables.

Results

BMI and WC were highly related to adiposity while W/Ht was moderately related. The association of BMI with FM and SAT was independent of sex and race, while the relationships of WC and W/Ht with FM and SAT were influenced by both sex and race. In contrast, the association between BMI and VAT was influenced by sex and race, while the relationships of WC and W/Ht with VAT were not.

Conclusions

WC and W/Ht have similar relationships with adiposity; however, WC presented stronger relationships. BMI is a predictor of overall adiposity but sex and race play a role in its relationship with VAT.
The number of chews and meal duration affect diet‐induced thermogenesis and splanchnic circulation
Authors: Hamada Yuka , Kashima Hideaki , Hayashi Naoyuki
Published: February 2014

Objective

To determine the effects of the number of chews and meal duration on diet‐induced thermogenesis (DIT) and splanchnic blood flow (BF).

Methods

Healthy normal‐weight subjects (11 subjects in the 100‐kcal test and 10 subjects in the 300‐kcal test) participated in two trials: a rapid‐eating trial and a slow‐eating trial. The meal duration and the number of chews were recorded. DIT was calculated from oxygen uptake and body mass, and splanchnic BF was calculated from the diameters of and blood velocities in the celiac artery and superior mesenteric artery, which were recorded until 90 min after consuming the food samples.

Results

For the 100‐kcal and 300‐kcal food samples, DIT and postprandial splanchnic BF in both the celiac artery and superior mesenteric artery were significantly larger in the slow‐eating trial than in the rapid‐eating trial. There were significant correlations among meal duration, the number of chews, DIT, and postprandial splanchnic BF, with the exception of the relationship between DIT and splanchnic BF in the 300‐kcal trial.

Conclusions

These results suggest that fewer chews and/or shorter meal duration decreases DIT and the postprandial splanchnic BF, and that the increased DIT is at least partially due to the postprandial splanchnic circulation.
An optimal control approach to spacecraft rendezvous on elliptical orbit
Authors: Gao Xiangyu , Teo Kok Lay , Duan Guang‐Ren
Published: February 2014

In this paper, we consider a linear quadratic regulator control problem for spacecraft rendezvous in an elliptical orbit. A new spacecraft rendezvous model is established. On the basis of this model, a linear quadratic regulator control problem is formulated. A parametric Lyapunov differential equation approach is used to design a state feedback controller such that the resulting closed‐loop system is asymptotically stable, and the performance index is minimized. By an appropriate choice of the value of a parameter, an approximate state feedback controller is obtained from a solution to the periodic Lyapunov differential equation, where the periodic Lyapunov differential equation is solved on the basis of a new numerical algorithm. The spacecraft rendezvous mission under the controller obtained will be accomplished successfully. Several illustrative examples are provided to show the effectiveness of the proposed control design method. Copyright © 2014 John Wiley & Sons, Ltd.
Rheological and transport properties of sulfonated polyacrylamide hydrogels for water shutoff in porous media
Authors: Salehi Mahsa Baghban , Vasheghani‐Farahani Ebrahim , Sefti Mohsen Vafaie , Moghadam Asefe Mousavi , Naderi Hasan
Published: February 2014

In this research, an optimal hydrogel, based on sulfonated polyacrylamide, was synthesized by statistical design of experiments using central composite method. This new hydrogel composed of sulfonated polyacrylamide (AN125VLM) and chromium triacetate as copolymer and crosslinker, respectively. The bottle and rheological tests were conducted to investigate the gelation time, thermal stability, gel strength and also ultimate elastic modulus, complex modulus, and yield stress. It was found that copolymer concentration had the main effect in both rheological and transport properties of hydrogels. The sample prepared at optimum condition, i.e. copolymer concentration of 26,340 ppm and crosslinker/copolymer ratio of 0.12, had an ultimate elastic modulus of 29.9 kPa, yield stress of 800 Pa, and complex modulus of 32 kPa. A coreflooding test through fracture was carried out to examine the optimum gel performance in a porous media. A value of 483 for the residual resistance factor ratio of water to oil confirmed the high ability of the hydrogel in reducing the relative permeability of water to oil in fractured media. Copyright © 2014 John Wiley & Sons, Ltd.
Study of film formation from PS latex/TiO2 nanocomposites; Effect of latex size and TiO2 content
Authors: Uğur Şaziye , Selin Sunay M. , Pekcan Önder
Published: February 2014

In this work, we investigated the film formation from polystyrene (PS) latex/TiO2 nanocomposites using the steady state fluorescence (SSF) and UV–vis (UVV) techniques depending on PS particle size and TiO2 content. The structural properties of films were characterized by scanning electron microscope (SEM). The films were prepared from pyrene (P)‐labeled PS particles (SmPS:203 nm; LgPS:382 nm) by covering them with different layers of TiO2 by dip‐coating method and then annealed at elevated temperatures. Two film series (SmPS/TiO2 and LgPS/TiO2) were prepared and seven different films were studied in various TiO2 contents for each series. Scattered (Isc), fluorescence (IP), and transmitted (Itr) light intensities were measured after each annealing step to monitor the stages of film formation. Results showed that, SmPS/TiO2 films undergo complete film formation independent of TiO2 content. However, no film formation occurs above a certain TiO2 content in LgPS/TiO2 films. SEM images showed that SmPS/TiO2 films have highly well‐ordered microporous structures with increasing TiO2 content after extraction of PS polymer whereas LgPS/TiO2 composites show no porous structure for high TiO2 content. Our experiments also showed that porous TiO2 films with different sizes could be successfully prepared using this technique. POLYM. COMPOS., 35:2376–2389, 2014. © 2014 Society of Plastics Engineers
Photocatalysis, microstructure, and surface characterization of TiO2‐loaded wooden‐activated carbon fibers
Authors: Liu Xinyan , Ma Xiaojun , Zhu Lizhi , Li Dongna
Published: February 2014

In this study, TiO2‐loaded wooden‐activated carbon fibers (TiO2/WACFs) were prepared by sol–gel method. TiO2/WACFs were detected by scanning electron microscopy, X‐ray diffraction, Fourier transform infrared spectroscopy, and X‐ray photoelectron spectroscopy. The results showed that TiO2 was deposited on almost each WCAF with a coating thickness. All the TiO2 films on the surface of WACFs were composed of anatase with high photocatalytic property. The characteristic adsorption peaks of nano‐TiO2 emerged at 1,402 and 471 cm−1 on the infrared spectrum of TiO2/WACFs. It was also found that Ti was in the binding state of Ti4+ (TiO2) in the TiO2/WACFs. As the calcination temperature increased, the content of elements Ti and TiO bond of lattice oxygen on the surface of TiO2/WACFs increased and then decreased, but the loaded nano‐TiO2 did not affect the formation of graphite structure of WACFs. It is suggested that TiO2/WACFs obtained at 450°C have the best photocatalytic property. POLYM. COMPOS., 36:62–68, 2015. © 2014 Society of Plastics Engineers
Sample Preparation Issues in NMR‐based Plant Metabolomics: Optimisation for Vitis Wood Samples
Authors: Halabalaki Maria , Bertrand Samuel , Stefanou Anna , Gindro Katia , Kostidis Sarantos , Mikros Emmanuel , Skaltsounis Leandros A. , Wolfender Jean‐Luc
Published: February 2014

Introduction

Nuclear magnetic resonance (NMR) is one of the most commonly used analytical techniques in plant metabolomics. Although this technique is very reproducible and simple to implement, sample preparation procedures have a great impact on the quality of the metabolomics data.

Objective

Investigation of different sample preparation methods and establishment of an optimised protocol for untargeted NMR‐based metabolomics of Vitis vinifera L. wood samples.

Methods

Wood samples from two different cultivars of V. vinifera with well‐defined phenotypes (Gamaret and 2091) were selected as reference materials. Different extraction solvents (successively, dichloromethane, methanol and water, as well as ethyl acetate and 7:3 methanol‐water (v/v)) and deuterated solvents (methanol‐d4, 7:3 chloroform‐d‐methanol‐d4 (v/v), dimethylsulphoxide‐d6 and 9:1 dimethylsulphoxide‐d6‐water‐d2 (v/v)) were evaluated for NMR acquisition, and the spectral quality was compared. The optimal extract concentration, chemical shift stability and peak area repeatability were also investigated.

Results

Ethyl acetate was found to be the most satisfactory solvent for the extraction of all representative chemical classes of secondary metabolites in V. vinifera wood. The optimal concentration of dried extract was 10 mg/mL and 7:3 chloroform‐d‐methanol‐d4 (v/v) was the most suitable solvent system for NMR analysis. Multivariate data analysis was used to estimate the biological variation and clustering between different cultivars.

Conclusion

Close attention should be paid to all required procedures before NMR analysis, especially to the selection of an extraction solvent and a deuterated solvent system to perform an extensive metabolomic survey of the specific matrix. Copyright © 2014 John Wiley & Sons, Ltd.