bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on poly(lactic acid)/natural fibers composites
Authors: Zhang Qi , Shi Longmin , Nie Jun , Wang Haiyan , Yang Dongzhi
Published: April 2012

Recently, the natural fibers‐reinforced composites have attracted substantial attention as a potential structural material for low cost applications. The composites of poly(lactic acid) (PLA) with three kinds of natural fibers, such as bamboo fibers, wood fibers, and coconut fibers (CTFs), were prepared by solution‐casting technique. The natural fibers were modified by aluminum acid ester coupling agent and stearic acid to improve compatibility. To compare the mechanical and thermal properties of composites, tensile test, dynamic mechanical analysis, differential scan calorimeter, scanning electron microscopy (SEM), and Vicat softening point test were carried. The results showed that the addition of three kinds of natural fibers all could improve the mechanical and thermal properties of composites, and natural fibers after modification could further improve tensile strength of composites. And in comparison, the composite of PLA/CTF had highest tensile strength and best thermal properties. When the content of natural fibers were 2%, the highest tensile strength of PLA/modified CTF composites was highest, and it reached 22.5 Mpa which was 20.4% higher than that of pure PLA, and VST of this composite increased compared with pure PLA. Meanwhile, the results of SEM indicated that the modified CTF had best interfacial compatibility to PLA. These results indicated that PLA/natural fiber composites had higher strength and better heat resistance than pure PLA. This study provided the application of PLA industry with a feasible method. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Dispersion polymerization of acrylamide with water‐soluble chitosan as the stabilizer
Authors: Liu Juan , Wang Chuanxing , Wu Yumin
Published: April 2012

A cationic polyelectrolyte of P (CMTC‐AM‐DMC) was synthesized by dispersion polymerization in aqueous solution of ammonium chloride, with acrylamide and dimethylaminoethyl methacrylate methyl chloride as main raw materials. N‐carboxymethylthioureidochitosan was used as both the reactant and the stabilizer, and 2,2′‐azobis (2‐amidinopropane) dihydrochloride (V‐50) as the initiator. The effects of the major reaction variables such as the concentration of inorganic salt and initiator, temperature, reaction time, and pH on the polymerization were discussed in this article. The optimal conditions of the polymerization were determined by orthogonal tests. The results showed that an increase in salt concentration resulted in an increase of molecular weight and particle size and a decrease of apparent viscosity, while when salt concentration was up to 23.9%, apparent viscosity was slightly higher than others. Molecular weight, particle size, and apparent viscosity all decreased with the increase of initiator. The apparent viscosity, molecular weight, and particle size would decrease with pH, and the product would be coagulated when pH > 7. Temperature influenced the characteristic a lot. Overall conversion was less dependent on these factors except for the temperature. Molecular weight and overall conversion increased gradually with the time, and the monomers could react completely at about 5–7 h. Flocculation occurred with 13% of salt concentration, 0.005% of initiator, and pH > 7. The optimal reaction conditions for obtaining a stable aqueous dispersion were 22.3% for ammonium chloride, 0.007% for initiator, react under 55 °C for 5 h at pH = 4. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synthesis and Anticonvulsant Activities of Some Triazolothiadiazole Derivatives
Authors: Deng Xian‐Qing , Dong Zheng‐Qi , Song Ming‐Xia , Shu Bing , Wang Shi‐Ben , Quan Zhe‐Shan
Published: April 2012

The present study describes the synthesis and anticonvulsant activity evaluation of 6‐substituted‐[1,2,4]triazolo[3,4‐b][1,3,4]thiadiazole derivatives (4a–4x) and their partially dehydrogenated products 5,6‐dihydro‐6‐substituted‐[1,2,4]triazolo[3,4‐b][1,3,4]thiadiazole derivatives (5a–5n). The bioevaluation demonstrated that most compounds in the series of 4a–4x exhibited potent anticonvulsant activity in the maximal electroshock test. Among which, 6‐(4‐chlorophenyl)‐[1,2,4]triazolo[3,4‐b][1,3,4]thiadiazole (4h) emerged as the most promising candidate on the basis of its favorable ED50 value of 23.7 mg/kg and PI value of 10.8. In addition, the potency of compound 4h against seizures induced by pentylenetetrazole, 3‐mercaptopropionic acid, and bicuculline in the chemical‐induced seizure tests suggested that compound 4h displayed broad‐spectrum activity in several models, and it may exert its anticonvulsant activity through affecting the GABAergic system.
LRRC8 proteins share a common ancestor with pannexins, and may form hexameric channels involved in cell‐cell communication
Authors: Abascal Federico , Zardoya Rafael
Published: April 2012

Leucine‐rich repeat‐containing 8 (LRRC8) proteins are composed of four transmembrane helices and 17 leucine‐rich repeats (LRR). Although LRRC8 proteins have been associated with important processes, like maturation of B cells or adipocyte differentiation, their biology and molecular function are largely unknown. We found that LRRC8 proteins originated from the combination of a pannexin and an LRR domain (most likely related to the SHOC2, LAP, RSU1 and LRRIQ4 protein families) before the diversification of chordates. We propose that, like pannexins, LRRC8 proteins form hexameric channels, which participate in cell‐cell communication processes. According to the inferred topological model, and contrary to what was previously assumed, the six LRR domains are located in the cytoplasm, and could participate in the organisation of signalling cascades. By compiling available proteomics and gene expression data, and on the basis of the LRRC8 proposed hexameric channel structure, we present clues to the function of this family.

Editor's suggested further reading in BioEssays Pannexins, distant relatives of the connexin family with specific cellular functions? Abstract
Subcellular Localization and Activity of Gambogic Acid
Authors: Guizzunti Gianni , Batova Ayse , Chantarasriwong Oraphin , Dakanali Marianna , Theodorakis Emmanuel A.
Published: April 2012

The natural product gambogic acid (GA) has shown significant potential as an anticancer agent as it is able to induce apoptosis in multiple tumor cell lines, including multidrug‐resistant cell lines, as well as displaying antitumor activity in animal models. Despite the fact that GA has entered phase I clinical trials, the primary cellular target and mode of action of this compound remain unclear, although many proteins have been shown to be affected by it. By thorough analysis of several cellular organelles, at both the morphological and functional levels, we demonstrate that the primary effect of GA is at the mitochondria. We found that GA induces mitochondrial damage within minutes of incubation at low‐micromolar concentrations. Moreover, a fluorescent derivative of GA was able to localize specifically to the mitochondria and was displaced from these organelles after competition with unlabeled GA. These findings indicate that GA directly targets the mitochondria to induce the intrinsic pathway of apoptosis, and thus represents a new member of the mitocans.
Disparity between angiographic coronary lesion complexity and lipid core plaques assessed by near‐infrared spectroscopy
Authors: Zynda Todd K. , Thompson Caleb D. , Hoang Khiet C. , Seto Arnold H. , Glovaci Diana , Wong Nathan D. , Patel Pranav M. , Kern Morton J.
Published: April 2012

Objective

The purpose of this study was to determine if there was a relationship between angiographic lesion complexity and the extent of lipid core plaque (LCP) identified by catheter‐based near‐infrared spectroscopy (NIRS).

Background

The angiographic complexity of coronary artery disease (CAD) is used to predict outcomes in patients undergoing percutaneous coronary intervention (PCI). The SYNTAX score, an angiographic tool quantifying the complexity of CAD, is associated with PCI outcomes. Recently, a novel catheter‐based imaging technique using NIRS can identify LCP, which also is associated with PCI periprocedural myocardial infarction (MI). However, it is unknown whether these events are related to distinct adverse event prone pathobiology, such as a LCP within a complex angiographic lesion. Thus, we hypothesized that LCP identified by NIRS would be associated with high SYNTAX score.

Methods

Seventy‐eight patients who underwent coronary angiography and target‐vessel NIRS were selected from the Chemometric Observations of Lipid Core Containing Plaques of Interest in Native Coronary Arteries Registry, an industry sponsored registry to collate clinical findings in all patients undergoing NIRS evaluation. A lipid core burden index (LCBI) was obtained from the scan of the proximal 50 mm of the target vessel. Three vessel SYNTAX (total, tSYN) and target single vessel (only NIRS‐interrogated vessel) SYNTAX (1vSYN) scores were calculated and compared to LCBI. High LCBI was defined as (>110) and was compared to tertile scores for 1vSYN score (low 0–5, intermediate 6–10, high ≥11) and previously established tertiles for tSYN score (low 0–22, intermediate 23–32, high ≥33).

Results

Patients had mean age of 63 years with prevalence of females (10%), diabetes mellitus (28%), hypertension (88%), and smoking history (72%); 1vSYN and tSYN scores correlated poorly with LCBI [(r2 = 0.25; P = 0.02; n = 78) and (r2 = 0.24; P = 0.04; n = 78), respectively]. Mean LCBI did not differ significantly across all tertiles of 1vSYN or tSYN scores.

Conclusions

Angiographic SYNTAX score only weakly correlated with LCBI. It is of interest as well that high LCBI was also present in cases of low SYNTAX scores. The disparity between the degree of angiographic complexity and the amount of LCP supports postulated mechanisms of the adverse event propensity even in patients who demonstrate low angiographic complexity. Future studies are necessary to address the clinical significance of high LCBI in patients with low‐to‐intermediate angiographic complexity and their potential for PCI‐related complications. © 2012 Wiley Periodicals, Inc.
Janus‐Like Squaramide‐Based Hosts: Dual Mode of Binding and Conformational Transitions Driven by Ion‐Pair Recognition
Authors: Soberats Bartomeu , Martínez Luis , Sanna Elena , Sampedro Angel , Rotger Carmen , Costa Antoni
Published: April 2012

New tripodal squaramide‐based hosts have been synthesised and structurally characterised by spectroscopic methods. In 2.5 % (v/v) [D6]DMSO in CDCl3, compound 4 formed dimeric assemblies [log Kdim=3.68(8)] as demonstrated by 1H NMR spectroscopy and UV dilution experiments. AFM and SEM analyses revealed the formation of a network of bundled fibres, which indicates a preferential mechanism for aggregation. These C3‐symmetric tripodal hosts exhibited two different and mutually exclusive modes of binding, each one easily accessible by simultaneous reorientation of the squaramide groups. In the first, a convergent disposition of the NH squaramide protons allowed the formation of an array of NH⋅⋅⋅X− hydrogen bonds with anions. In the second mode, reorientation of carbonyl squaramide groups allowed multiple CO⋅⋅⋅H interactions with ammonium cations. The titration of 4 with different tetraalkylammonium iodides persistently showed the formation of 1:1 complexes, as well as 1:2 and 1:3 complexes. The corresponding stoichiometries and binding affinities of the complexes were evaluated by multi‐regression analysis. The formation of high‐order complexes, supported by ROESY, NOESY and mass spectrometry experiments, has been attributed to the insertion of NR4I ion pairs between the carbonyl and NH protons of the squaramide groups located in adjacent arms of 4. The observed effects reflect the induction of significant conformational changes in the hosts, mainly in relation to the relative orientation of the squaramide groups adapting their geometries to incoming ion‐pair complementary substrates. The results presented herein identify and fully describe two different modes of ion‐pair recognition aimed at directing conformational transitions in the host, therefore establishing a base for controlling more elaborate movements of molecular devices through ion‐pair recognition.
Optically Transparent Hydrogels from an Auxin–Amino‐Acid Conjugate Super Hydrogelator and its Interactions with an Entrapped Dye
Authors: Reddy Amarendar , Sharma Aashish , Srivastava Aasheesh
Published: April 2012

Low‐molecular‐weight organic hydrogelators (LMHGs) that can rigidify water into soft materials are desirable in various applications. Herein, we report the excellent hydrogelating properties of a simple synthetic auxin–amino‐acid conjugate, naphthalene‐1‐acetamide of L‐phenylalanine (1‐NapF, Mw=333.38 Da), which gelated water even at 0.025 wt %, thereby making it the most‐efficient LMHG known. Optically transparent gels that exhibited negligible scattering in the range 350–900 nm were obtained. A large shift from the theoretical pKa value of the gelator was observed. The dependence of the minimum gelator concentration (MGC) and the gel‐melting temperatures on the pH value indicated the importance of H‐bonding between the carboxylate groups on adjacent phenylalanine molecules in the gelator assembly. FTIR spectroscopy of the xerogels showed a β‐sheet‐like assembly of the gelator. Variable‐temperature 1H NMR spectroscopy demonstrated that π stacking of the aromatic residues was also partly involved in the gelator assembly. TEM of the xerogel showed the presence of a dense network of thin, high‐aspect‐ratio fibrillar assemblies with diameters of about 5 nm and lengths that exceeded a few microns. Rheology studies showed the formation of stable gels. The entrapment of water‐soluble dyes afforded extremely fluorescent gels that involved the formation of J‐aggregates by the dye within gel. A strong induced‐CD band established that the RhoB molecules were interacting closely with the chiral gelator aggregates. H‐bonding and electrostatic interactions, rather than intercalation, seemed to be involved in RhoB binding. The addition of chaotropic reagents, as well as increasing the pH value, disassembled the gel and promoted the release of the entrapped dye with zero‐order kinetics.
Chiral Hetero‐ and Carbocyclic Compounds from the Asymmetric Hydrogenation of Cyclic Alkenes
Authors: Verendel J. Johan , Li Jia‐Qi , Quan Xu , Peters Byron , Zhou Taigang , Gautun Odd R. , Govender Thavendran , Andersson Pher G.
Published: April 2012

Several types of chiral hetero‐ and carbocyclic compounds have been synthesized by using the asymmetric hydrogenation of cyclic alkenes. N,P‐Ligated iridium catalysts reduced six‐membered cyclic alkenes with various substituents and heterofunctionality in good to excellent enantioselectivity, whereas the reduction of five‐membered cyclic alkenes was generally less selective, giving modest enantiomeric excesses. The stereoselectivity of the hydrogenation depended more strongly on the substrate structure for the five‐ rather than the six‐membered cyclic alkenes. The major enantiomer formed in the reduction of six‐membered alkenes could be predicted from a selectivity model and isomeric alkenes had complementary enantioselectivity, giving opposite optical isomers upon hydrogenation. The utility of the reaction was demonstrated by using it as a key step in the preparation of chiral 1,3‐cis‐cyclohexane carboxylates.
Challenges in Climate Science and Contemporary Applied Mathematics
Authors: Majda Andrew J.
Published: April 2012

This article discusses the challenges in climate science from the emerging viewpoint of stochastic‐statistical properties of turbulent dynamical systems. The mathematical topics discussed here include empirical information theory, fluctuation‐dissipation theorems, reduced‐order stochastic modeling, and the development of mathematically unambiguous exactly solvable test models for climate science that capture crucial features of vastly more complex scientific problems. The applied mathematics topics include the emerging development of multiscale algorithms for filtering/data assimilation and superparametrization for climate science and other problems in science and engineering, as well as suitable unambiguous mathematical test problems for their behavior. Interesting contemporary research directions and specific open problems are mentioned throughout the article. The perspective here should also be useful for applications to other complex dynamical systems arising in neural science, material science, and environmental/mechanical engineering. © 2011 Wiley Periodicals, Inc.
Thermodynamic Aspects of the Synthesis of Thin‐Film Materials for Solar Cells
Authors: Scragg Jonathan J. , Dale Phillip J. , Colombara Diego , Peter Laurence M.
Published: April 2012

A simple and useful thermodynamic approach to the prediction of reactions taking place during thermal treatment of layers of multinary semiconductor compounds on different substrates has been developed. The method, which uses the extensive information for the possible binary compounds to assess the stability of multinary phases, is illustrated with the examples of Cu(In,Ga)Se2 and Cu2ZnSnSe4 as well as other less‐studied ternary and quaternary semiconductors that have the potential for use as absorbers in photovoltaic devices.
A Highly Stable Anode, Carbon‐Free, Catalyst Support Based on Tungsten Trioxide Nanoclusters for Proton‐Exchange Membrane Fuel Cells
Authors: Dou Meiling , Hou Ming , Zhang Huabing , Li Guangfu , Lu Wangting , Wei Zidong , Shao Zhigang , Yi Baolian
Published: April 2012

Durability is an important issue in proton‐exchange membrane fuel cells (PEMFCs). One of the major challenges lies in the degradation caused by the oxidation of the carbon support under high anode potentials (under fuel starvation conditions). Herein, we report highly stable, carbon‐free, WO3 nanoclusters as catalyst supports. The WO3 nanoclusters are synthesized through a hard template method and characterized by means of electron microscopy and electrochemical analysis. The electrochemical studies show that the WO3 nanoclusters have excellent electrochemical stability under a high potential (1.6 V for 10 h) compared to Vulcan XC‐72. Pt nanoparticles supported on these nanoclusters exhibit high and stable electrocatalytic activity for the oxidation of hydrogen. The catalyst shows negligible loss in electrochemically active surface area (ECA) after an accelerated durability test, whereas the ECA of the Pt nanoparticles immobilized on conventional carbon decreases significantly after the same oxidation condition. Therefore, Pt/WO3 could be considered as a promising alternative anode catalyst for PEMFCs.
Loss of central and peripheral CD8+T‐cell tolerance to HFE in mouse models of human familial hemochromatosis
Authors: Boucherma Rachid , Kridane‐Miledi Hédia , Langa Vives Francina , Vauchy Charline , Borg Christophe , Kleinclauss François , Fiette Laurence , Tiberghien Pierre , Lemonnier François A. , Rohrlich Pierre S. , Huetz François
Published: April 2012

HFE, an MHC class Ib molecule that controls iron metabolism, can be directly targeted by cytotoxic TCR αβ T lymphocytes. Transgenic DBA/2 mice expressing, in a Rag 2 KO context, an αβ TCR that directly recognizes mouse HFE (mHFE) were created to further explore the interface of HFE with the immune system. TCR‐transgenic mHfe WT mice deleted mHFE‐reactive T cells in the thymus, but a fraction of reprogrammed cells were able to escape deletion. In contrast, TCR‐transgenic mice deprived of mHFE molecules (mHfe KO mice) or expressing a C282→Y mutated mHFE molecule – the most frequent mutation associated with human hereditary hemochromatosis – positively selected mHFE‐reactive CD8+ T lymphocytes and were not tolerant toward mHFE. By engrafting these mice with DBA/2 WT (mHFE+) skin, it was established, as suspected on the basis of similar engraftments performed on DBA/2 mHfe KO mice, that mHFE behaves as an autonomous skin‐associated histocompatibility antigen, even for mHFE‐C282→Y mutated mice. By contrast, infusion of DBA/2 mHFE+ mice with naïve mHFE‐reactive transgenic CD8+ T lymphocytes did not induce GVHD. Thus, tolerance toward HFE in mHfe WT mice can be acquired at either thymic or peripheral levels but is disrupted in mice reproducing human familial hemochromatosis.
Chronic smoke exposure induces rheumatoid factor and anti‐heat shock protein 70 autoantibodies in susceptible mice and humans with lung disease
Authors: Newkirk Marianna M. , Mitchell Simeon , Procino Michael , Li Zhenhong , Cosio Manuel , Mazur Witold , Kinnula Vuokko L. , Hudson Marie , Baron Murray , Fritzler Marvin J. , El‐Gabalawy Hani S.
Published: April 2012

The impact of cigarette smoke (CS), a risk factor for rheumatoid arthritis (RA), on sauto‐antibody production was studied in humans and mice with and without chronic lung disease (LD). Rheumatoid factor (RF), anti‐cyclic citrullinated peptides (CCPs), and anti‐HSP70 autoantibodies were measured in several mouse strains and in cohorts of smokers and nonsmokers with and without autoimmune disease. Chronic smoking‐induced RFs in AKR/J mice, which are most susceptible to LD. RFs were identified in human smokers, preferentially in those with LD. Anti‐HSP70 auto‐antibodies were identified in CS‐exposed AKR/J mice but not in ambient air exposed AKR/J controls. Whereas inflammation could induce anti‐HSP70 IgM, smoke exposure promoted the switch to anti‐HSP70 IgG autoantibodies. Elevated anti‐CCP autoantibodies were not detected in CS‐exposed mice or smokers. AKR/J splenocytes stimulated in vitro by immune complexes (ICs) of HSP70/anti‐HSP70 antibodies produced RFs. The CD91 scavenger pathway was required as anti‐CD91 blocked the HSP70‐IC‐induced RF response. Blocking Toll‐like receptors did not influence the HSP70‐IC‐induced RFs. These studies identify both anti‐HSP70 and RFs as serological markers of smoke‐related LD in humans and mice. Identification of these autoantibodies could suggest a common environmental insult, namely CS, in a number of different disease settings.
Prostaglandin E2 modulates IL‐8 expression through formation of a multiprotein enhanceosome in human colonic epithelial cells
Authors: Srivastava Vikas , Dey Indranil , Leung Pearl , Chadee Kris
Published: April 2012

Gastrointestinal inflammation is mediated by the pro‐inflammatory mediators interleukin‐8 (IL‐8) and prostaglandin E2 (PGE2). PGE2 binding and coupling through EP2/4 receptor subtypes on colonic epithelial cells stimulates cyclic adenosine monophosphate (cAMP) and IL‐8 production. Here we determined the mechanisms whereby PGE2 regu‐lates IL‐8 in Caco2 colonic epithelial cells and in cells over‐expressing the EP2/4 receptors (EP2S/EP4S). PGE2 coupling through EP2 activated the transcription factor inducible cAMP early repressor (ICER), whereas coupling through EP4 receptors activated the cyclic AMP‐responsive element‐binding protein (CREB). Activation of CREB in Caco2/EP2S was protein kinase A (PKA) dependent, whereas in EP4S cells, activation of CREB occurred through the PKA and phosphatidylinositol 3‐kinase pathways. Since ICER lacks the transactivation domain, it functions as a transcription repressor as opposed to CREB. PGE2 coupling through EP2/4 receptors can therefore acts in an opposing manner to either decrease (EP2) or promote IL‐8 expression by recruiting CREB‐binding protein (CBP) (EP4), which formed a multiprotein IL‐8 enhanceosome. A novel half CRE (167CRE) and a composite NFAT1‐AP1‐like site in the IL‐8 promoter participated in binding and complex formation as confirmed by mutagenesis and expression studies. These data unravel the mechanisms by which expression of IL‐8 is controlled by different signalling pathways that are activated by PGE2 but acting through different EP receptors.
FOXO3 as a new IKK‐ε‐controlled check‐point of regulation of IFN‐β expression
Authors: Luron Lionel , Saliba David , Blazek Katrina , Lanfrancotti Alessandra , Udalova Irina A.
Published: April 2012

Cell survival transcription factor FOXO3 has been recently implicated in moderating pro‐inflammatory cytokine production by dendritic cells (DCs), but the molecular mechanisms are unclear. It was suggested that FOXO3 could antagonize NF‐κB activity, while IKK‐β was demonstrated to inactivate FOXO3, suggesting a cross‐talk between the two pathways. Therefore, FOXO3 activity must be tightly regulated to allow for an appropriate inflammatory response. Here, we show that in human monocyte‐derived DCs (MDDCs), FOXO3 is able to antagonize signaling intermediates downstream of the Toll‐like receptor (TLR) 4, such as NF‐κB and interferon regulatory factors (IRFs), resulting in inhibition of interferon (IFN)‐β expression. We also demonstrate that the activity of FOXO3 itself is regulated by IKK‐ε, a kinase involved in IFN‐β production, which phosphorylates and inactivates FOXO3 in response to TLR4 agonists. Thus, we identify FOXO3 as a new IKK‐ε‐controlled check‐point of IRF activation and regulation of IFN‐β expression, providing new insight into the role of FOXO3 in immune response control.
Lineage extrinsic and intrinsic control of immunoregulatory cell numbers by SHIP
Authors: Collazo Michelle M. , Paraiso Kim H. T. , Park Mi‐Young , Hazen Amy L. , Kerr William G.
Published: April 2012

We previously showed that germline or induced SHIP deficiency expands immuno‐regulatory cell numbers in T lymphoid and myeloid lineages. We postulated these increases could be interrelated. Here, we show that myeloid‐specific ablation of SHIP leads to the expansion of both myeloid‐derived suppressor cell (MDSC) and regulatory T (Treg) cell numbers, indicating SHIP‐dependent control of Treg‐cell numbers by a myeloid cell type. Conversely, T‐lineage specific ablation of SHIP leads to expansion of Treg‐cell numbers, but not expansion of the MDSC compartment, indicating SHIP also has a lineage intrinsic role in limiting Treg‐cell numbers. However, the SHIP‐deficient myeloid cell that promotes MDSC and Treg‐cell expansion is not an MDSC as they lack SHIP protein expression. Thus, regulation of MDSC numbers in vivo must be controlled in a cell‐extrinsic fashion by another myeloid cell type. We had previously shown that G‐CSF levels are profoundly increased in SHIP−/− mice, suggesting this myelopoietic growth factor could promote MDSC expansion in a cell‐extrinsic fashion. Consistent with this hypothesis, we find that G‐CSF is required for expansion of the MDSC splenic compartment in mice rendered SHIP‐deficient as adults. Thus, SHIP controls MDSC numbers, in part, by limiting production of the myelopoietic growth factor G‐CSF.
Overexpression of Snai3 suppresses lymphoid‐ and enhances myeloid‐cell differentiation
Authors: Dahlem Timothy , Cho Scott , Spangrude Gerald J. , Weis Janis J. , Weis John H.
Published: April 2012

The altered expression of transcription factors in hematopoietic stem cells and their subsequent lineages can alter the development of lymphoid and myeloid lineages. The role of the transcriptional repressor Snai3 protein in the derivation of cells of the hemato‐poietic system was investigated. Snai3 is expressed in terminal T‐cell and myeloid lineages, therefore, we chose to determine if expressing Snai3 in the early stages of hematopoietic development would influence cell‐lineage determination. Expression of Snai3 by retroviral transduction of hematopoietic stem cells using bone marrow chimera studies demonstrated a block in lymphoid‐cell development and enhanced expansion of myeloid‐lineage cells. Analysis of Snai3‐expressing hematopoietic precursor cells showed normal numbers of immature cells, but a block in the development of cells committed to lymphoid lineages. These data indicate that the overexpression of Snai3 does alter bone marrow cell development and that the identification of genes whose expression is altered by the presence of Snai3 would aid in our understanding of these developmental pathways.
Taurine: Energy drink for T cells
Authors: Bachmann Martin F.
Published: April 2012

The activation of T cells causes many cellular changes, including alterations in cell morphology, motility, and size. While all immunologists know that T cells increase their size and become “blasted” upon activation, little attention has been paid to the question of how cell size is regulated and how this process influences T‐cell responses. In this issue of the European Journal of Immunology, Kaesler et al. [Eur. J. Immunol. 2012. 42: 831‐841] demonstrate that the organic osmolyte taurine and its transporter Taut are instrumental in driving cell‐volume regulation and therefore the T‐cell response. In the absence of Taut, effector and memory T‐cell responses in mice are severely impaired, mainly due to increased apoptosis of effector cells. Hence, this paper provides an important link between the regulation of cell size and effector T‐cell responses.
Redistribution of monocarboxylate transporter 2 on the surface of astrocytes in the human epileptogenic hippocampus
Authors: Lauritzen Fredrik , Heuser Kjell , de Lanerolle Nihal C. , Lee Tih‐Shih W. , Spencer Dennis D. , Kim Jung H. , Gjedde Albert , Eid Tore , Bergersen Linda H.
Published: April 2012

Emerging evidence points to monocarboxylates as key players in the pathophysiology of temporal lobe epilepsy (TLE) with hippocampal sclerosis (mesial temporal lobe epilepsy, MTLE). Monocarboxylate transporters (MCTs) 1 and 2, which are abundantly present on brain endothelial cells and perivascular astrocyte endfeet, respectively, facilitate the transport of monocarboxylates and protons across cell membranes. Recently, we reported that the density of MCT1 protein is reduced on endothelial cells and increased on astrocyte plasma membranes in the hippocampal formation in patients with MTLE and in several animal models of the disorder. Because the perivascular astrocyte endfeet comprise an important part of the neurovascular unit, we now assessed the distribution of the MCT2 in hippocampal formations in TLE patients with (MTLE) or without hippocampal sclerosis (non‐MTLE). Light microscopic immunohistochemistry revealed significantly less perivascular MCT2 immunoreactivity in the hippocampal formation in MTLE (n = 6) than in non‐MTLE (n = 6) patients, and to a lesser degree in non‐MTLE than in nonepilepsy patients (n = 4). Immunogold electron microscopy indicated that the loss of MCT2 protein occurred on perivascular astrocyte endfeet. Interestingly, the loss of MCT2 on astrocyte endfeet in MTLE (n = 3) was accompanied by an upregulation of the protein on astrocyte membranes facing synapses in the neuropil, when compared with non‐MTLE (n = 3). We propose that the altered distribution of MCT1 and MCT2 in TLE (especially MTLE) limits the flux of monocarboxylates across the blood–brain barrier and enhances the exchange of monocarboxylates within the brain parenchyma. © 2012 Wiley Periodicals, Inc.
Towards a comprehensive approach to parameter estimation in land surface parameterization schemes
Authors: Rosolem Rafael , Gupta Hoshin V. , Shuttleworth W. James , de Gonçalves Luis Gustavo Gonçalves , Zeng Xubin
Published: April 2012

In climate models, the land–atmosphere interactions are described numerically by land surface parameterization (LSP) schemes. The continuing improvement in realism in these schemes comes at the expense of the need to specify a large number of parameters that are either directly measured or estimated. Also, an emerging problem is whether the relationships used in LSPs are universal and globally applicable. One plausible approach to evaluate this is to first minimize uncertainty in model parameters by calibration. In this paper, we conduct a comprehensive analysis of some model diagnostics using a slightly modified version of the Simple Biosphere 3 model for a variety of biomes located mainly in the Amazon. First, the degree of influence of each individual parameter in simulating surface fluxes is identified. Next, we estimate parameters using a multi‐operator genetic algorithm applied in a multi‐objective context and evaluate simulations of energy and carbon fluxes against observations. Compared with the default parameter sets, these parameter estimates improve the partitioning of energy fluxes in forest and cropland sites and provide better simulations of daytime increases in assimilation of net carbon during the dry season at forest sites. Finally, a detailed assessment of the parameter estimation problem was performed by accounting for the decomposition of the mean squared error to the total model uncertainty. Analysis of the total prediction uncertainty reveals that the parameter adjustments significantly improve reproduction of the mean and variability of the flux time series at all sites and generally remove seasonality of the errors but do not improve dynamical properties. Our results demonstrate that error decomposition provides a meaningful and intuitive way to understand differences in model performance. To make further advancements in the knowledge of these models, we encourage the LSP community to adopt similar approaches in the future. Copyright © 2012 John Wiley & Sons, Ltd.
Attachment‐based intervention for substance‐using mothers: A preliminary test of the proposed mechanisms of change
Authors: Suchman Nancy E. , Decoste Cindy , Rosenberger Patricia , McMahon Thomas J.
Published: April 2012

Although randomized controlled trials examining the efficacy of attachment‐based interventions have been increasing in recent years, adequate measurement of treatment integrity, integrity–outcome associations, and mechanisms of change has been rare. The aim of this investigation was to conduct a rigorous test of proposed mechanisms of change in the Mothers and Toddlers Program (MTP) treatment model, a 12‐session, attachment‐based individual therapy for substance‐using mothers of children birth to 3 years of age. The MTP aims to improve maternal reflective functioning (RF) and representation quality (RQ) to bring about second‐order change in maternal caregiving behavior. Following guidelines from M.K. Nock (2007), it was hypothesized that (a) therapist adherence to unique MTP treatment components would uniquely predict improvement in RF and RQ and that (b) improvement in RF and RQ would function as unique mechanisms of change (when compared with other potential mechanisms—reduction in depression and increase in abstinence from drug use) in the improvement of caregiving behavior. Findings supported each hypothesis, confirming the proposed mechanisms of the treatment model. However, improvement in maternal depression also uniquely predicted improvement in caregiving behavior. Results underscore the potential value of attachment‐based parenting interventions for improving mother–child relations and the importance of providing these interventions in clinic settings where mothers have access to comprehensive care (e.g., psychiatric services).
Reversible photoswitching in fluorescent proteins: A mechanistic view
Authors: Bourgeois Dominique , Adam Virgile
Published: April 2012

Phototransformable fluorescent proteins (FPs) have received considerable attention in recent years, because they enable many new exciting modalities in fluorescence microscopy and biotechnology. On illumination with proper actinic light, phototransformable FPs are amenable to long‐lived transitions between various fluorescent or nonfluorescent states, resulting in processes known as photoactivation, photoconversion, or photoswitching. Here, we review the subclass of photoswitchable FPs with a mechanistic perspective. These proteins offer the widest range of practical applications, including reversible high‐density data bio‐storage, photochromic FRET, and super‐resolution microscopy by either point‐scanning, structured illumination, or single molecule‐based wide‐field approaches. Photoswitching can be engineered to occur with high contrast in both Hydrozoan and Anthozoan FPs and typically results from a combination of chromophore cis‐trans isomerization and protonation change. However, other switching schemes based on, for example, chromophore hydration/dehydration have been discovered, and it seems clear that ever more performant variants will be developed in the future. © 2012 IUBMB IUBMB Life, 2012
Real‐time three‐dimensional echocardiographic evaluation of left ventricular systolic synchronicity in patients with chronic heart failure: Comparison with tissue doppler imaging
Authors: Li Dong‐ye , Liang Li , Cao Guang‐ke , Xia Yong , Xu Tong‐da , Chen Jing , Wang Xiao‐ping , Chen Jun‐hong
Published: April 2012

Background.

To investigate the clinical value of real‐time three‐dimensional echocardiography (RT‐3DE) for assessing of left ventricular systolic synchronicity.

Methods.

Thirty healthy volunteers and 62 patients with congestive heart failure (CHF) were enrolled. The SD of time to peak systolic motion (TDI‐Ts12‐SD) was measured with tissue Doppler imaging in 12 myocardial segments. The SD and maximal difference of the time to minimal systolic volume (Tmsv) between 16, 12, or 6 myocardial segments, expressed as a percentage of cardiac cycle duration, were measured with RT‐3DE and labeled Tmsv16‐SD%, Tmsv12‐SD%, Tmsv6‐SD%, Tmsv16‐D%, Tmsv12‐D%, and Tmsv6‐D%, respectively. The Spearman coefficient and Kappa value were calculated, and Bland‐Altman analysis was performed to investigate the correlation and agreement between the two methods. Tmsv values were compared with ejection fraction (EF).

Results.

There was a moderately positive (p< 0.01) correlation between TDI‐Ts12‐SD and Tmsv16‐SD%, Tmsv12‐SD%, Tmsv16‐D%, and Tmsv12‐D% (r = 0.65, 0.64, and 0.65, respectively, with Kappa values of 0.66, 0.65, 0.72, and 0.74, respectively, p< 0.01). Tmsv16‐SD%, Tmsv12‐SD%, and Tmsv12‐D% were significantly different between CHF patients with EF ≤ 35% and those with EF > 35%.

Conclusions.

RT‐3DE can be used in patients with CHF to quantify left ventricular mechanical dyssynchrony. Tmsv12‐SD% and Tmsv12‐D% were the best indices of left ventricular systolic synchronicity in relation to the severity of CHF as evaluated from EF. © 2012 Wiley Periodicals, Inc. J Clin Ultrasound 40:410–418, 2012
Test–retest stability analysis of resting brain activity revealed by blood oxygen level‐dependent functional MRI
Authors: Li Zhengjun , Kadivar Aniseh , Pluta John , Dunlop John , Wang Ze
Published: April 2012

Purpose:

To assess test–retest stability of four functional magnetic resonance imaging (fMRI)‐derived resting brain activity metrics: the seed‐region‐based functional connectivity (SRFC), independent component analysis (ICA)‐derived network‐based FC (NTFC), regional homogeneity (ReHo), and the amplitude of low frequency fluctuation (ALFF).

Methods:

Simulations were used to assess the sensitivity of SRFC, ReHo, and ALFF to noise interference. Repeat resting blood oxygen level‐dependent (BOLD) fMRI were acquired from 32 healthy subjects. The intraclass correlation coefficient (ICC) was used to assess the stability of the four metrics.

Results:

Random noise yielded small random SRFC, small but consistent ReHo and ALFF. A neighborhood size greater than 20 voxels should be used for calculating ReHo in order to reduce the noise interference. Both the anterior cingulate cortex (ACC) and posterior cingulate cortex (PCC)‐based SRFC were reproducible in more spatially extended regions than ICA NTFC. The two regional spontaneous brain activity (SBA) measures, ReHo and ALFF, showed test–retest reproducibility in almost the whole gray matter.

Conclusion:

SRFC, ReHo, and ALFF are robust to random noise interference. The neighborhood size for calculating ReHo should be larger than 20 voxels. ICC > 0.5 and cluster size > 11 should be used to assess the ICC maps for ACC/PCC SRFC, ReHo, and ALFF. BOLD fMRI‐based SBA can be reliably measured using ACC/PCC SRFC, ReHo, and ALFF after 2 months. J. Magn. Reson. Imaging 2012;36:344–354. ©2012 Wiley Periodicals, Inc.
Management of complications following pancreatic resection: An evidence‐based approach
Authors: Mezhir James J.
Published: April 2012

Despite significant improvements in operative mortality, morbidity remains a significant problem following pancreatectomy. Management of postpancreatectomy complications, namely pancreatic fistula, begins with a clear understanding of how these events are defined. There are now several unifying definitions for complications following pancreatectomy which have led to improved reporting of operative outcomes across institutions. Several randomized controlled trials have been performed in recent years that may lead to continued improvement in operative outcomes. J. Surg. Oncol. 2013;107:58–66. © 2012 Wiley Periodicals, Inc.
Application of an elastoplastic spectral‐element method to 3D slope stability analysis
Authors: Gharti Hom Nath , Komatitsch Dimitri , Oye Volker , Martin Roland , Tromp Jeroen
Published: April 2012

We implement a spectral‐element method for 3D time‐independent elastoplastic problems in geomechanics. As a first application, we use the method for slope stability analyses ranging from small to large scales. The implementation employs an element‐by‐element preconditioned conjugate‐gradient solver for efficient storage. The program accommodates material heterogeneity and complex topography. Either simple or complex water table profiles may be used to assess effects of hydrostatic pressure. Both surface loading and pseudostatic seismic loading are implemented. For elastoplastic behavior of slopes to be simulated, a Mohr–Coulomb yield criterion is employed using an initial strain method (i.e., a viscoplastic algorithm). For large‐scale problems, the software is parallelized on the basis of domain decomposition using Message Passing Interface. Strong‐scaling measurements demonstrate that the parallelized software performs efficiently. We validate our spectral‐element results against several other methods and apply the technique to simulate failure of an earthen embankment and a mountain slope.Copyright © 2012 John Wiley & Sons, Ltd.
Biomarkers for risk stratification of febrile neutropenia among children with malignancy: A pilot study
Authors: Mian Amir , Becton David , Saylors Robert , James Laura , Tang Xinyu , Bhutta Adnan , Prodhan Parthak
Published: April 2012

Background

Patients receiving myelosuppressive chemotherapy remain at increased risk for developing febrile neutropenia (FN). For this heterogeneous population, a biomarker based risk stratification of FN patients may be a useful clinical tool. We hypothesized that serum biomarkers during initial presentation of an FN event could be predictive of subsequent clinical outcome.

Procedure

Eighty‐nine FN events from 36 non‐consecutive subjects were analyzed. “High‐risk” FN criteria included prolonged hospitalization (≥7 days), admission to pediatric intensive care unit (PICU) or a microbiology confirmed bacteremia. Patients with “low risk” FN had none of the above. Biomarkers measured during the first 2 days of FN hospitalization were analyzed and correlated with respective clinical outcome.

Results

Of the 89 FN events, 44 (49%) fulfilled pre‐defined high‐risk criteria and 45 (51%) were low‐risk. Procalcitonin level (>0.11 ng/ml) was found to be associated with the high‐risk FN outcome with sensitivity of 97%. With an increase in log scale by 1, the odds of being high‐risk FN increased twofold. Hs‐CRP >100 mg/L had sensitivity of 88% in predicting high‐risk FN. The odds of a high‐risk FN event increased by approximately 1.8‐fold with an increase in the log scale of hs‐CRP by 1 (10‐fold). In univariate analysis, IL‐6, IL‐8, and IL‐10 were statistically significant and associated with high‐risk FN. However, no statistically significant difference was found for IL‐1α, sIL‐2Ra, IL‐3, or TNF‐α.

Conclusions

Biomarkers with appropriate critical threshold values may be a useful clinical tool for appropriate risk stratification of children with FN. Pediatr Blood Cancer 2012;59:238–245. © 2012 Wiley Periodicals, Inc.
Malignant ectomesenchymoma in children and adolescents: Report from the Cooperative Weichteilsarkom Studiengruppe (CWS)
Authors: Dantonello Tobias M. , Leuschner Ivo , Vokuhl Christian , Gfroerer Stefan , Schuck Andreas , Kube Stefanie , Nathrath Michaela , Bernbeck Benedikt , Kaatsch Peter , Pal Niklas , Ljungman Gustaf , Bielack Stefan S. , Klingebiel Thomas , Koscielniak Ewa ,   on behalf of CWS
Published: April 2012

Background

Malignant ectomesenchymoma (MEM) is a soft tissue tumor with heterologous rhabdomyoblastic components believed to arise from pluripotent migratory neural crest cells. To date merely 50 cases have been published and the knowledge about the course of disease and optimal treatment is limited.

Methods

Six patients with MEM were registered 1996–2009. The diagnosis was confirmed according to current criteria. Their treatment and outcome was analyzed.

Results

The median age of the three females and three males was 0.6 years (range, 0.2–13.5). The mesenchymal component in all tumors was rhabdomyosarcoma (RMS), the neural component ganglioneuroblastoma/neuroblastoma (n = 5) and peripheral primitive neuroectodermal tumor in one case. Five patients presented with localized, one with metastatic disease. All but one patient received multiagent chemotherapy during their initial treatment. The tumors of 4/5 patients with localized MEM were at least grossly resected at best surgery; the patient without gross resection was additionally irradiated. Three of four evaluable tumors responded well to induction chemotherapy. All patients achieved a first complete remission (CR), but three recurrences (two local, one systemic) occurred. The individual with metastatic MEM did not survive, but all five patients with localized MEM are currently alive in CR with a median follow‐up of 5 years (range: 2.1–13.7).

Conclusions

Risk‐factors and outcome of MEM appear to be comparable with other highly malignant pediatric soft tissue sarcoma when a multimodal treatment strategy including chemotherapy and adequate local treatment is pursued. We propose that treatment of patients with MEM be done according to pediatric protocols similar to other rhabdomyosarcoma‐like soft tissue sarcoma. Pediatr Blood Cancer 2013;60:224–229. © 2012 Wiley Periodicals, Inc.
Electric‐field tuning of magnetoelectric properties in Metglas/piezofiber composites
Authors: Wang Yaojin , Hasanyan Davresh , Li Menghui , Gao Junqi , Viswan Ravindranath , Li Jiefang , Viehland D.
Published: April 2012

The tunability of magnetoelectric (ME) properties by applied dc electric field (E) was systematically investigated for a laminate composite consisting of Metglas, Pb(Zrx Ti1–x)O3 fiber, and interdigitated electrodes. The ME coefficients and equivalent magnetic noise were found to be dependent on E. This dependence is attributed to variations in the magnetic properties. The dielectric properties and noise charge density were relatively invariant to E. A 1.3× improvement in the ME coefficient was obtained at the Villari point under E = 300 V/mm relative to E = 0 V/mm. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Organizational differences, relational mechanisms, and alliance performance
Authors: Lavie Dovev , Haunschild Pamela R. , Khanna Poonam
Published: April 2012

In studying the antecedents of alliance performance, one stream of research has underscored the alignment between partners' characteristics whereas another has concentrated on relational mechanisms such as mutual trust, relational embeddedness, and relational commitment. We integrate these two perspectives by examining how congruence of the partners' cultures and organizational routines facilitates the emergence of relational mechanisms in non‐equity alliances. Our analysis of 420 non‐equity alliances in the information technology industry demonstrates how differences in partners' internal task routines undermine relational mechanisms that in turn impact alliance performance. Partners who acknowledge their latent differences can overcome some of these negative consequences. We advance alliance research by studying the performance implications of alliance partners' organizational differences and by demonstrating how these effects are mediated by relational mechanisms. Copyright © 2012 John Wiley & Sons, Ltd.