bluuebunny/crossref_metadata_2025 huggingface dataset:
Expression and regulation of AC133 and CD133 in glioblastoma
Authors: Campos Benito , Zeng Lingcheng , DaoTrong Philip H. , Eckstein Volker , Unterberg Andreas , Mairbäurl Heimo , Herold‐Mende Christel
Published: September 2011

The biological significance of CD133 in glioblastoma is controversial. Above all, there is disagreement concerning the proper approach, the appropriate (cell) model and the suitable microenvironment to study this molecule, often leading to inconsistent experimental results among studies. In consideration of a primary need to dissect and to understand the CD133 phenotype in glioblastoma we performed a comprehensive analysis of CD133 expression and regulation in a large set of glioblastoma cell lines (n = 20) as well as in tumor xenografts. Our analysis considered alternatively spliced mRNA transcripts, different protein epitopes as well as varying sub‐cellular localizations of CD133 and explored its regulation under pertinent micro‐environmental conditions. CD133 mRNA and CD133 protein could be detected in all relevant types of glioblastoma cell lines. In addition, we detected frequent intracellular CD133 protein accumulations located to the ER and/or Golgi apparatus but seemingly unrelated to particular CD133 splice variants or protein epitopes. In contrast, membrane‐bound expression of CD133 was restricted to tumor cells bearing the extracellular CD133 epitope AC133. Only in these cells, differentiation and oxygen levels clearly impacted on AC133 expression and to some extent also influenced CD133 mRNA and protein expression. Most importantly, however, modulation of AC133 levels could occur independently of changes in CD133 mRNA transcription, CD133 protein translation, protein retention or protein shedding. Our results suggest that the AC133 epitope, rather than CD133 mRNA or protein, mirrors malignancy‐related tumor traits such as tumor differentiation and local oxygen tension levels, and thus corroborate its role as a biologically relevant cancer marker. © 2011 Wiley‐Liss, Inc.
Nitric oxide induces the expression of the monocarboxylate transporter MCT4 in cultured astrocytes by a cGMP‐independent transcriptional activation
Authors: Marcillac Fabrice , Brix Britta , Repond Cendrine , Jöhren Olaf , Pellerin Luc
Published: September 2011

The monocarboxylate transporter MCT4 is a proton‐linked carrier particularly important for lactate release from highly glycolytic cells. In the central nervous system, MCT4 is exclusively expressed by astrocytes. Surprisingly, MCT4 expression in primary cultures of mouse cortical astrocytes is conspicuously low, suggesting that an external, nonastrocytic signal is necessary to obtain the observed pattern of expression in vivo. Here, we demonstrate that nitric oxide (NO), delivered by various NO donors, time‐ and dose‐dependently induces MCT4 expression in cultured cortical astrocytes both at the mRNA and protein levels. In contrast, NO does not enhance the expression of MCT1, the other astrocytic monocarboxylate transporter. The transcriptional effect of NO is not mediated by a cGMP‐dependent mechanism as shown by the absence of effect of a cGMP analog or of a selective guanylate cyclase inhibitor. NO causes an increase in astrocytic lactate transport capacity which requires the enhancement of MCT4 expression as both are prevented by the use of a specific siRNA against MCT4. In addition, cumulated lactate release by astrocytes over a period of 24 h was also enhanced by NO treatment. Our data suggest that NO represents a putative intercellular signal to control MCT4 expression in astrocytes and in doing so, to facilitate lactate transfer to other surrounding cell types in the central nervous system. © 2011 Wiley‐Liss, Inc.
Heat and mass transfer effects on peristaltic flow of an Oldroyd‐B fluid in a channel with compliant walls
Authors: Hayat T. , Hina S. , Hendi Awatif A.
Published: September 2011

This investigation describes the peristaltic motion of a magnetohydrodynamic (MHD) Oldroyd‐B fluid with heat and mass transfer. An incompressible Oldroyd‐B fluid is considered in a channel with flexible walls. The relevant equations are developed by employing equations of continuity, momentum, energy, and concentration. Expressions of stream function, temperature, concentration field, and heat transfer coefficient are presented when the wave number is small. The obtained solutions are graphically discussed for the several interesting parameters entering into the problem. It is found that relaxation and retardation times have opposite effects on the size of the trapped bolus. © 2011 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library (wileyonlinelibrary.com/journal/htj). DOI 10.1002/htj.20380
Boundary layer flow of an Oldroyd‐B fluid with convective boundary conditions
Authors: Hayat T. , Iqbal Z. , Mustafa M. , Obaidat S.
Published: September 2011

This study is presented for the flow of an Oldroyd‐B fluid subject to convective boundary conditions. The two‐dimensional equations are simplified by using boundary layer approximations. The analytic solutions in the whole spatial domain (0 ≤ η < ∞) are derived by a homotopy analysis method (HAM). Interpretation of various emerging parameters is assigned through graphs for velocity and temperature distributions and tables for surface heat transfer. The present results are compared with the previous studies in limiting cases and results are found in very good agreement. © 2011 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library (wileyonlinelibrary.com/journal/htj). DOI 10.1002/htj.20381
The relationships of ‘ecstasy’ (MDMA) and cannabis use to impaired executive inhibition and access to semantic long‐term memory
Authors: Murphy Philip N. , Erwin Philip G. , Maciver Linda , Fisk John E. , Larkin Derek , Wareing Michelle , Montgomery Catharine , Hilton Joanne , Tames Frank J. , Bradley Belinda , Yanulevitch Kate , Ralley Richard
Published: September 2011

This study aimed to examine the relationship between the consumption of ecstasy (3,4‐methylenedioxymethamphetamine (MDMA)) and cannabis, and performance on the random letter generation task which generates dependent variables drawing upon executive inhibition and access to semantic long‐term memory (LTM). The participant group was a between‐participant independent variable with users of both ecstasy and cannabis (E/C group, n = 15), users of cannabis but not ecstasy (CA group, n = 13) and controls with no exposure to these drugs (CO group, n = 12). Dependent variables measured violations of randomness: number of repeat sequences, number of alphabetical sequences (both drawing upon inhibition) and redundancy (drawing upon access to semantic LTM). E/C participants showed significantly higher redundancy than CO participants but did not differ from CA participants. There were no significant effects for the other dependent variables. A regression model comprising intelligence measures and estimates of ecstasy and cannabis consumption predicted redundancy scores, but only cannabis consumption contributed significantly to this prediction. Impaired access to semantic LTM may be related to cannabis consumption, although the involvement of ecstasy and other stimulant drugs cannot be excluded here. Executive inhibitory functioning, as measured by the random letter generation task, is unrelated to ecstasy and cannabis consumption. Copyright © 2011 John Wiley & Sons, Ltd.
Fibronectin attachment protein from bacillus Calmette‐Guerin as targeting agent for bladder tumor cells
Authors: Coon Brian G. , Crist Scott , González‐Bonet Andrés M. , Kim Hee‐Kwon , Sowa Jennifer , Thompson David H. , Ratliff Timothy L. , Aguilar R. Claudio
Published: September 2011

The adjuvant therapy of choice for superficial bladder cancer is the intravesical instillation of live Mycobacterium bovis bacillus Calmette‐Guerin (BCG). Despite the fact that this therapy is the most effective treatment for superficial bladder cancer, intravesical administration of BCG is associated with high local morbidity and the potential for systemic infection. Therefore, there is a need for the development of safer, less toxic approaches to fight this disease. Because fibronectin attachment protein (FAP) is a key element in BCG retention and targeting to cells, we hypothesize that this protein can be used as targeting agent to deliver cytotoxic cargo for the treatment of bladder tumors. Here, we evaluated the ability of bladder tumor cells to bind and endocytose FAP via fibronectin–integrin complexes. We found that microaggregation induced by an anti‐FAP polyclonal antibody accelerated FAP uptake by T24 bladder tumor cells. FAP was determined to be internalized via a clathrin‐independent, caveolae‐dependent mechanism. Furthermore, once within the endosomal compartment, FAP was targeted to the lysosomal compartment with negligible recycling to the plasma membrane. Importantly, we demonstrated that FAP microaggregation and internalization could also be triggered by multivalent Ni2+NTA‐bearing liposomes. Overall, our studies validate the use of FAP as a targeting vector and provide the foundation for the design of more effective, less‐toxic bladder cancer therapeutics.
Urokinase plasminogen activator receptor on invasive cancer cells: A prognostic factor in distal gastric adenocarcinoma
Authors: Alpízar‐Alpízar Warner , Christensen Ib Jarle , Santoni‐Rugiu Eric , Skarstein Arne , Ovrebo Kjell , Illemann Martin , Laerum Ole Didrik
Published: September 2011

Gastric cancer is the second cancer causing death worldwide. The five‐year survival for this malignancy is below 25% and few parameters have shown an impact on the prognosis of the disease. The receptor for urokinase plasminogen activator (uPAR) is involved in extracellular matrix degradation by mediating cell surface associated plasminogen activation, and its presence on gastric cancer cells is linked to micrometastasis and poor prognosis. Using immunohistochemistry, the prognostic significance of uPAR was evaluated in tissue samples from a retrospective series of 95 gastric cancer patients. uPAR was expressed by neoplastic cells, macrophages, myofibroblasts and neutrophils in both intestinal and diffuse subtypes. No association was demonstrated between the expression of uPAR on cancer cells and histological subtype (p = 0.64) or TNM stage (p = 0.75). Univariate analysis revealed a significant association between the expression of uPAR on tumor cells in the peripheral invasion zone and overall survival of gastric cancer patients (HR = 2.16; 95% CI: 1.13–4.14; p = 0.02). Multivariate analysis showed that uPAR immunoreactivity in cancer cells at the invasive front is an independent prognostic factor for overall survival in gastric cancer (HR = 2.39; 95% CI: 1.22–4.69; p = 0.011). In consequence, scoring of uPAR‐positive cancer cells may be a direct measure for the invasive potential of gastric adenocarcinomas.
Neural integration of reward, arousal, and feeding: Recruitment of VTA, lateral hypothalamus, and ventral striatal neurons
Authors: Gutierrez Ranier , Lobo Mary Kay , Zhang Feng , de Lecea Luis
Published: September 2011

The ability to control neuronal activity using light pulses and optogenetic tools has revealed new properties of neural circuits and established causal relationships between activation of a single genetically defined population of neurons and complex behaviors. Here, we briefly review the causal effect of activity of six genetically defined neural circuits on behavior, including the dopaminergic neurons DA in the ventral tegmental area (VTA); the two main populations of medium‐sized spiny neurons (D1‐ and D2‐positive) in the striatum; the giant Cholinergic interneurons in the ventral striatum; and the hypocretin‐ and MCH‐ expressing neurons in the lateral hypothalamus. We argue that selective spatiotemporal recruitment and coordinated spiking activity among these cell type‐specific neural circuits may underlie the neural integration of reward, learning, arousal and feeding. © 2011 IUBMB IUBMB Life, 2011
CD38 through the life of a murine B lymphocyte
Authors: Vences‐Catalán Felipe , Santos‐Argumedo Leopoldo
Published: September 2011

CD38 is a 45 kDa transmembrane receptor expressed in B lymphocytes and other cells from the immune system. It is involved in apoptosis, cell activation, differentiation, and proliferation. CD38 has been used extensively to classify various subpopulations of lymphocytes in both humans and mice. It has also been used as a marker of poor prognosis in some lymphoid pathologies. However, CD38 is not a marker but rather an ectoenzyme and a receptor, where it performs several functions. The CD38 signaling pathway has only been partially studied in various cells of the immune system, where apparently the signaling is different depending on the lineage and differentiation state of the cell, leading to distinct outcomes. In this review, we provide an overview of well‐established roles of CD38 signaling B lymphocytes from mice. We also discuss areas that need further clarification to get a broader image of how CD38 performs different functions in B cells and to understand its role in B lymphocyte biology under normal versus pathological conditions. © 2011 IUBMB IUBMB Life, 2011
Progesterone and 17β‐estradiol increase differentiation of mouse embryonic stem cells to motor neurons
Authors: López‐González Rodrigo , Camacho‐Arroyo Ignacio , Velasco Iván
Published: September 2011

Embryonic stem (ES) cells have the capacity to differentiate into endodermal, mesodermal, and ectodermal lineages. Motor neuron (MN) differentiation of mouse ES cells involves embryoid bodies formation with addition of Sonic hedgehog and retinoic acid. In this work, using immunocytochemistry, flow cytometry, and quantitative RT‐PCR, we investigated whether progesterone or 17β‐estradiol have inductive effects on ES cell‐derived MN, as it has been demonstrated that these hormones modify proliferation and neural differentiation of pluripotent cells. When 100 nM progesterone was added during differentiation, we found higher proportions of MN, compared to the control condition; coincubation of progesterone with the progesterone receptor (PR) antagonist RU‐486 caused a decrease in the number of MN to a percentage even lower than controls. The addition of nanomolar concentrations of 17β‐estradiol also significantly induced MN differentiation. This effect of estradiol was completely antagonized by addition of the general estrogen receptor (ER) antagonist ICI 182,780. To identify the ER subtype mediating the increase on MN differentiation, we incubated estradiol with the ER‐α antagonist MPP or with the ER‐β blocker PHTPP. When we coincubated 17β‐estradiol with MPP, we found a significant decrease in the percentage of MN. In contrast, the coincubation of 17β‐estradiol with PHTPP had no effect on the induction of MN differentiation. All these effects on cell number were confirmed by significant changes in the expression of the MN markers Islet‐1 and Choline acetyl transferase, assessed by real‐time RT‐PCR. Cell proliferation in embryoid bodies was significantly enhanced by progesterone treatment. No changes in apoptotic cell death were found in differentiating cells after progesterone or 17β‐estradiol addition. Our findings indicate that progesterone and 17β‐estradiol induce a higher proportion of MN derived from mouse ES cells through intracellular PR and ER, respectively. Furthermore, the effect of estradiol was mediated by specific activation of ER‐α. © 2011 IUBMB IUBMB Life, 2011
Density functional theory‐based electrochemical models for the oxygen reduction reaction: Comparison of modeling approaches for electric field and solvent effects
Authors: Yeh Kuan‐Yu , Janik Michael J.
Published: September 2011

A series of density functional theory (DFT) based electrochemical models are applied to systematically examine the effect of solvent, local electric field, and electrode potential on oxygen reduction reaction (ORR) kinetics. Specifically, the key elementary reaction steps of molecular oxygen dissociation, molecular oxygen protonation, and reduction of a hydroxyl adsorbate to water over the Pt(111) surface were considered. The local electric field has slight influence on reaction energetics at the vacuum interface. Solvent molecules stabilize surface adsorbates, assisting oxygen reduction. A collective solvation‐potential coupled effect is identified by including long range solvent‐solvent interactions in the DFT model. The dominant path of the ORR reaction varies with electrode potential and among the modeling approaches considered. The potential dependent reaction path determined from the solvated model qualitatively agrees with experiment ORR kinetics. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
Application of analytical electron microscopic methods to investigate the function of spherites in the midgut of the larval antlion Euroleon nostras (Neuroptera: Myrmeleontidae)
Authors: Lipovšek Saška , Letofsky‐Papst Ilse , Hofer Ferdinand , Pabst Maria Anna , Devetak Dušan
Published: September 2011

This study presents an application of analytical electron microscopy in biology to investigate the chemical composition of the spherites and to elucidate the importance of these methods in the life sciences. The structure of the spherites in the midgut cells of first, second, and third instar larvae Euroleon nostras was investigated by a combination of transmission electron microscopy (TEM), energy dispersive X‐ray spectroscopy (EDXS), electron energy‐loss spectroscopy (EELS), and energy filtering TEM (EFTEM). The structure and chemical composition of the spherites changed during the metamorphosis. In first larvae, the spherites are composed of amorphous, flocculent material, containing C, N, and O. In second larvae and third ones, the spherites have concentric layers of alternating electron‐dense and electron‐lucent material. In second larvae, Si, P, Ca, and Fe are accumulated in the spherite organic matrix, composed of C, N, and O. In the spherites of third larvae, additionally Al was found. Therefore, the spherites are thought to store organic compounds in all three larval stages of E. nostras and additionally inorganic compounds in second and third ones. In first larvae, spherites are present in the midgut cells; in second and third larvae, they are present in the cells of the midgut and in its lumen. It could be suggested that the spherites might be involved in the regulation of the appropriate mineral composition of the internal environment and could serve as the accumulation site of nontoxic waste materials that cannot be metabolized. Microsc. Res. Tech., 2011. © 2011 Wiley‐Liss, Inc.
Immunohistochemical detection and quantification of T cells in the small intestine of Isospora suis‐infected piglets—influence of fixation technique and intestinal segment
Authors: Gabner Simone , Tonar Zbyněk , Tichy Alexander , Saalmüller Armin , Worliczek Hanna Lucia , Joachim Anja , Witter Kirsti
Published: September 2011

Quantification of immunohistochemical results constitutes an important tool in the analysis of cells and tissue that is not readily replaced by other techniques. For reliable quantification, it is essential to consider factors such as tissue fixation and tissue sampling. We report a study on the model of the intestine of Isospora suis‐infected piglets, in which we addressed (1) whether the quantity of detectable T cells in the intestinal mucosa is the same in formalin‐, HOPE®‐, and cryo‐conserved material or whether the amounts of T cells at least correlate with one another; and (2) whether single jejunal segments differ in regard to the quantity of mucosal T cells and variability of lymphocyte infiltration. Quantification of T cells in histological sections of different parts of the jejunum of 15‐22 day old piglets infected with I. suis was performed using an anti‐CD3‐antibody and stereological point counting. Area fractions of T‐cell profiles per intestinal mucosa profile were higher in cryo‐conserved samples than in HOPE®‐ and formalin‐conserved material but no correlation between different fixations could be found. The proximal part of the jejunum contained fewer T cells compared with mid‐ and end‐jejunum. Coefficients of variation did not differ between the intestinal segments. For quantification of T cells in the gut mucosa of piglets infected with I. suis, the cryo‐conserved mid jejunum seems most suitable in cases when unbiased sampling of the complete intestine is not feasible. It is generally not possible to compare quantitative results of immunostaining in samples conserved by different methods. Microsc. Res. Tech., 2011. © 2011 Wiley‐Liss, Inc.
Synthesis of deuterium and C‐13‐labelled ethyl glycolate and their subsequent use in the synthesis of labelled analogues of the DNA adduct O6‐carboxymethyl‐2′‐deoxyguanosine
Authors: Moore Sharon A. , Shuker David E. G.
Published: September 2011

The adduct O6‐carboxymethyl‐2′‐deoxyguanosine (O6CMdG) is of importance as it has been previously linked to high red meat diet in humans, and as yet, a liquid chromatography‐mass spectrometry (LC‐MS) method has not been developed due to lack of appropriate standards. The synthesis of the deuterated and C‐13 analogues required the use of [2H2]‐ and [13C2]ethyl glycolate to label the carboxymethyl moiety of O6CMdG. [2H2]Ethyl glycolate was synthesised via acid hydrolysis of ethyl diazoacetate using deuterated solvents (59% yield), whilst [13C2]ethyl glycolate was synthesised from [13C2]glycine in a three‐step procedure (35% yield). The labelled ethyl glycolates were then used to synthesise [2H2]‐ and [13C2]O6CMdG for future use as internal standards in the LC‐MS analysis of biological samples. Copyright © 2011 John Wiley & Sons, Ltd.
EMG‐driven modeling approach to muscle force and joint load estimations: Case study in knee osteoarthritis
Authors: Kumar Deepak , Rudolph Katherine S. , Manal Kurt T.
Published: September 2011

It is important to know the magnitude and patterns of joint loading in people with knee osteoarthritis (OA), since altered loads are implicated in onset and progression of the disease. We used an EMG‐driven forward dynamics model to estimate joint loads during walking in a subject with knee OA and a healthy control subject. Kinematic, kinetic, and surface EMG data were used to predict muscle forces using a Hill‐type muscle model. The muscle forces were used to balance the frontal plane moment to obtain medial and lateral condylar loads. Loads were normalized to body weight (BWs) and the mean of three trials taken. The OA subject had greater medial and lower lateral loads compared to the control subject. Seventy‐five to 80% of the total load was borne on the medial compartment in the control subject, compared to 90–95% in the OA subject. In fact, complete lateral unloading occurred during midstance for the OA subject. Loading for the healthy subject was consistent with the data from instrumented knee studies. In the future, the model can be used to analyze the impact of various interventions to reduce the loads on the medial compartment in people with knee OA. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 30:377–383, 2012
North Atlantic climate impact on early late‐glacial climate oscillations in the south‐eastern Alps inferred from a multi‐proxy lake sediment record
Authors: Schmidt Roland , Weckström Kaarina , Lauterbach Stefan , Tessadri Richard , Huber Kerstin
Published: September 2011

High‐resolution multi‐proxy analyses of a sediment core section from Lake Jeserzersee (Saissersee) in the piedmont lobe of the Würmian Drau glacier (Carinthia, Austria) reveal pronounced climatic oscillations during the early late glacial (ca. 18.5–16.0k cal a BP). Diatom‐inferred epilimnetic summer water temperatures show a close correspondence with temperature reconstructions from the adjacent Lake Längsee record and, on a hemispheric scale, with fluctuations of ice‐rafted debris in the North Atlantic. This suggests that North Atlantic climate triggered summer climate variability in the Alps during the early late glacial. The expansion of pine (mainly dwarf pine) between ca. 18.5 and 18.1k cal a BP indicates warming during the so‐called ‘Längsee oscillation’. The subsequent stepwise climate deterioration between ca. 18.1 and 17.6k cal a BP culminated in a tripartite cold period between ca. 17.6 and 16.9k cal a BP with diatom‐inferred summer water temperatures 8.5–10 °C below modern values and a shift from wet to dry conditions. This period probably coincides with a major Alpine glacier advance termed the Gschnitz stadial. A warmer interval between ca. 16.9 and 16.4k cal a BP separates this cold phase from a second, shorter and less pronounced cold phase between ca. 16.4 and 16.0k cal a BP, which is thought to correlate with the Clavadel/Senders glacier advance in the Alps. The following temperature increase, coupled with wet (probably snow‐rich) conditions, caused the expansion of birch during the transition period to the late glacial interstadial. Copyright © 2011 John Wiley & Sons, Ltd.
A Facile Approach to Fabricate Self‐Standing Gel‐Polymer Electrolytes for Flexible Lithium‐Ion Batteries by Exploitation of UV‐Cured Trivalent/Monovalent Acrylate Polymer Matrices
Authors: Kil Eun‐Hye , Ha Hyo‐Jeong , Lee Sang‐Young
Published: September 2011

A facile approach to fabricate a self‐standing GPE for flexible lithium‐ion batteries is demonstrated using a UV‐cured trivalent/monovalent acrylate polymer matrix and a liquid electrolyte. The polymer matrix is successfully synthesized with the co‐presence of the liquid electrolyte by UV polymerization of ETPTA, which has trivalent vinyl groups, and EGMEA, which contains monovalent vinyl groups, with the ETPTA/EGMEA ratio fixed at 90/10 (wt%/wt%). The ETPTA/EGMEA matrix shows a lower Tg than the ETPTA matrix alone, which helps improve the mechanical flexibility and ionic transport of the resulting GPE. These features of the ETPTA/EGMEA‐based GPE, together with its superior interfacial compatibility towards electrodes, play crucial roles in obtaining a better cell performance compared to the ETPTA‐based GPE.
Tunable Arrangement of Gold Nanoparticles in Epoxidated Poly(styrene‐block‐butadiene) Diblock Copolymer Matrices
Authors: Kuo Shiao‐Wei , Yang Hong‐Ying
Published: September 2011

A new approach to synthesize block‐copolymer‐mediated/gold nanoparticle (Au NP) composites is developed. Stable and narrowly distributed Au NPs modified with a 2‐phenylethanethiol ligand are prepared by a two‐phase liquid–liquid method. A new epoxidation of a poly(styrene‐block‐butadiene) diblock copolymer, to form poly(styrene‐block‐vinyl oxirane) (PS‐b‐PBO), is achieved through chemical modification. It is found that the Au NPs disperse well in the PS block segment by partially crosslinking the PBO block segment with poly(ethylene oxide bisamine) (D230), a curing agent. The aggregation of Au NPs leads to a red‐shift of the plasmon absorption with the increase in the D230 content. However, without crosslinking the PBO block segment with D230, Au NPs distributes in both the PS and PBO segments.
On the X‐rank with respect to linear projections of projective varieties
Authors: Ballico Edoardo , Bernardi Alessandra
Published: September 2011

In this paper we improve the known bound for the X‐rank RX(P) of an element \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$P\in {\mathbb {P}}^N$\end{document} in the case where \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$X\subset {\mathbb P}^n$\end{document} is a projective variety obtained as a linear projection from a general v‐dimensional subspace \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$V\subset {\mathbb P}^{n+v}$\end{document}. Then, if \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$X\subset {\mathbb P}^n$\end{document} is a curve obtained from a projection of a rational normal curve \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$C\subset {\mathbb P}^{n+1}$\end{document} from a point \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$O\subset {\mathbb P}^{n+1}$\end{document}, we are able to describe the precise value of the X‐rank for those points \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$P\in {\mathbb P}^n$\end{document} such that RX(P) ≤ RC(O) − 1 and to improve the general result. We also give a stratification, via the X‐rank, of the osculating spaces to projective cuspidal projective curves X. We give a description and a new bound of the X‐rank of subspaces both in the general case and with respect to integral non‐degenerate projective curves.
On notion of asymptotic derivations
Authors: Heo Jaeseong
Published: September 2011

In this paper we introduce some notion of asymptotic derivations of a C*‐ and W*‐dynamical systems which naturally arises from a one‐parameter group of automorphisms. We show that an asymptotic derivation on a unital simple C*‐algebra or a von Neumann algebra is asymptotically inner. Every asymptotic derivation on finite dimensional C*‐algebras is induced by an inner derivation. We prove that any asymptotic derivation on commutative von Neumann algebras have a strong limit zero. An asymptotic derivation on the hyperfinite II1‐factor given by some one‐parameter group of automorphisms can be induced by a (inner) derivation. Finally, we show that every asymptotic Jordan derivation of a C*‐dynamical system is an asymptotic derivation and is also induced by a derivation if there exists a limit.
Deciphering the Structural Requirements of Nucleoside Bisubstrate Analogues for Inhibition of MbtA in Mycobacterium tuberculosis: A FB‐QSAR Study and Combinatorial Library Generation for Identifying Potential Hits
Authors: Maganti Lakshmi , Das Sanjit Kumar , Mascarenhas Nahren Manuel , Ghoshal Nanda
Published: September 2011

The re‐emergence of tuberculosis infections, which are resistant to conventional drug therapy, has steadily risen in the last decade. Inhibitors of aryl acid adenylating enzyme known as MbtA, involved in siderophore biosynthesis in Mycobacterium tuberculosis, are being explored as potential antitubercular agents. The ability to identify fragments that interact with a biological target is a key step in fragment based drug design (FBDD). To expand the boundaries of quantitative structure activity relationship (QSAR) paradigm, we have proposed a Fragment Based QSAR methodology, referred here in as FB‐QSAR, for deciphering the structural requirements of a series of nucleoside bisubstrate analogs for inhibition of MbtA, a key enzyme involved in siderophore biosynthetic pathway. For the development of FB‐QSAR models, statistical techniques such as stepwise multiple linear regression (SMLR), genetic function approximation (GFA) and GFAspline were used. The predictive ability of the generated models was validated using different statistical metrics, and similarity‐based coverage estimation was carried out to define applicability boundaries. To aid the creation of novel antituberculosis compounds, a bioisosteric database was enumerated using the combichem approach endorsed mining in a lead‐like chemical space. The generated library was screened using an integrated in‐silico approach and potential hits identified.
Alkaloids from Hippeastrum morelianum Lem. (Amaryllidaceae)
Authors: Giordani Raquel B. , de Andrade Jean P. , Verli Hugo , Dutilh Julie H. , Henriques Amélia T. , Berkov Strahil , Bastida Jaume , Zuanazzi José Angelo S.
Published: September 2011

The Amaryllidaceae family has proven to be a rich source of active molecules. As part of an ongoing project, we report a phytochemical study of Hippeastrum morelianum (Amaryllidaceae), from which we have isolated two homolycorine‐type alkaloids, the new 2α,7‐dimethoxyhomolycorine (1) and the poorly described candimine (2), as well as six known alkaloids: tazettine, pretazettine, 3‐epimacronine, haemanthamine, hamayne and trisphaeridine. For reference purposes, the NMR of the isolated compounds was unequivocally described, based on 2D NMR measurements including 1H–1H COSY, 1H–1H NOESY, HSQC and HMBC. Copyright © 2011 John Wiley & Sons, Ltd.
Silencing disease genes in the laboratory and the clinic
Authors: Watts Jonathan K , Corey David R
Published: September 2011

Synthetic nucleic acids are commonly used laboratory tools for modulating gene expression and have the potential to be widely used in the clinic. Progress towards nucleic acid drugs, however, has been slow and many challenges remain to be overcome before their full impact on patient care can be understood. Antisense oligonucleotides (ASOs) and small interfering RNAs (siRNAs) are the two most widely used strategies for silencing gene expression. We first describe these two approaches and contrast their relative strengths and weaknesses for laboratory applications. We then review the choices faced during development of clinical candidates and the current state of clinical trials. Attitudes towards clinical development of nucleic acid silencing strategies have repeatedly swung from optimism to depression during the past 20 years. Our goal is to provide the information needed to design robust studies with oligonucleotides, making use of the strengths of each oligonucleotide technology. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Monitoring of Phenolic Compounds for the Quality Control of Melissa officinalis Products by Capillary Electrophoresis
Authors: Acosta Gimena , Arce Silvia , Martínez Luis D. , Llabot Juan , Gomez María R.
Published: September 2011

Introduction

Official assays for the quality control of Melissa officinalis L. (Lamiaceae) leaves establish the quantification of total hydroxycinnamic derivatives expressed as rosmarinic acid.

Objective

The goal of this work was to develop a simple, fast and reliable method for monitoring the phenolic composition in herbs from the Lamiaceae family and for rapidly detecting M. officinalis adulteration or substitution in commercial medicinal samples in Argentina.

Methodology

A capillary zone electrophoresis (CZE) method was performed under the following conditions: the background electrolyte (BGE) consisted of 20 m m sodium tetraborate buffer, pH 9.2; the applied voltage was 25 kV; the capillary and sample temperatures were kept at 25 °C; the hydrodynamic mode was selected for the sample injection (3.45 kPa during 5 s).

Results

A CZE method that achieved the separation and simultaneous determination of eight related phenolic compounds in less than 11 min was optimised for application to control quality analysis of M. officinalis‐based products. The method was validated according to the US Federal Drug Agency requirements and offers advantages in terms of analysis time, cost and operation.

Conclusions

The proposed methodology can be applied to the standardisation and quality control of plant material and phytopharmaceutical products derived from the Lamiaceae family, as indicated by the results obtained in the analysis of commercial medicinal products in Argentina. Copyright © 2011 John Wiley & Sons, Ltd.
HPLC Determination of Flavonoid Glycosides in Mongolian Dianthus versicolorFisch. (Caryophyllaceae) Compared with Quantification by UV Spectrophotometry
Authors: Obmann Astrid , Purevsuren Sodnomtseren , Zehl Martin , Kletter Christa , Reznicek Gottfried , Narantuya Samdan , Glasl Sabine
Published: September 2011

Introduction

Dianthus versicolor is used in traditional Mongolian medicine against liver impairment. Fractions enriched in flavone‐di‐ and triglycosides were shown to enhance bile secretion. Therefore, reliable and accurate analytical methods are needed for the determination of these flavonoids in the crude drug and extracts thereof.

Objective

To provide a validated HPLC‐DAD (diode array detector) method especially developed for the separation of polar flavonoids and to compare the data obtained with those evaluated by UV spectrophotometry.

Methodology

Separations were carried out on an Aquasil® C18‐column (4.6 mm × 250.0 mm, 5 µm) with a linear gradient of acetonitrile and water (adjusted to pH 2.8 with trifluoroacetic acid) as mobile phase. Rutoside was employed as internal standard with linear behavior in a concentration range of 0.007–3.5 mg/mL. Accuracy was determined by spiking the crude drug with saponarin resulting in recoveries between 92% and 102%.

Results

The method allows the quantification of highly polar flavonoid glycosides and the determination of their total content. For saponarin a linear response was evaluated within the range 0.007–3.5 mg/mL (R2 > 0.9999). It was proven that threefold sonication represents a time‐saving, effective and cheap method for the extraction of the polar flavonoid glycosides. The contents determined by HPLC were shown to be in agreement with those obtained employing UV spectrophotometry.

Conclusion

The study has indicated that the newly developed HPLC method represents a powerful technique for the quality control of D. versicolor. Ultraviolet spectrophotometry may be used alternatively provided that the less polar flavonoids are removed by purification. Copyright © 2011 John Wiley & Sons, Ltd.
The Use of Coupled HSQC Spectra to Aid in Stereochemical Assignments of Molecules with Severe Proton Spectral Overlap
Authors: Powder‐George Yomica , Frank Julia , Ramsewak Russel S. , Reynolds Willam F.
Published: September 2011

Introduction

A simple glycoside with only 13 carbons exhibited extensive overlapping of four of the glycosidic protons, causing extreme difficulty in the determination of the stereochemistry of the pyranose unit. However, acquisition of a high‐resolution coupled heteronuclear single‐quantum coherence (HSQC) spectrum overcame this problem. This spectrum provides a useful method for determining vicinal proton coupling constants between strongly coupled protons.

Objective

To show the potential of high‐resolution coupled HSQC spectra in overcoming spectral overlap.

Methodology

The sample was obtained by methanol extraction, followed by fractionation and column chromatography of the dried leaves of Montrichardia arborescens (Araceae). NMR spectra were obtained on 1.5 mg of sample dissolved in 120 μL of CD3OD containing 0.1% trimethylsilyl (TMS) as internal standard. A gradient‐selected HSQC spectrum was obtained using standard Varian library pulse sequences in phase sensitive mode. The high‐resolution coupled HSQC spectrum focused on the saccharide region with a 1025 Hz 1H spectral window, a 6300 Hz 13 C spectral window, 1024 data points, a 0.3 Hz relaxation delay, 384 time increments (linear predicted to 4096), and 80 scans per time increment.

Results

The use of a high‐resolution coupled HSQC spectrum allowed determination of the coupling patterns of the various pyranose protons with sufficient accuracy. This enabled completion of the assignments and identification of the pyranose unit as glucose.

Conclusion

The study has shown the effectiveness of the use of a high‐resolution coupled HSQC spectrum in the assignment of molecules with severe spectral overlap. Copyright © 2011 John Wiley & Sons, Ltd.
Kinetic and mechanistic study on the thermal isomerization of ocimene in the liquid phase
Authors: He Jindong , Xie Meng , Tang Xiangyang , Qi Xin
Published: September 2011

The rate of thermal isomerization of ocimene in the liquid phase has been investigated in the range 90–150 °C. The rate constant for the disappearance of ocimene may be expressed by k = 1. 3 × 1010e– 11994. 2/T(min– 1), from which we can infer that the activation energy is 99.7 kJ mol–1 and the pre‐exponential factor is 1.3 × 1010 min–1. The half‐life for the disappearance of ocimene may be expressed by t1/2 = 5. 2 × 10– 11e11994. 2/T(min). The conclusion has been supported by the study results that the ocimene is safe when temperature is below 100 °C. A discussion of the mechanism concerning the conversion is included. Copyright © 2011 John Wiley & Sons, Ltd.
Synthesis and self‐assembly of amphiphilic macrocyclic block copolymer topologies
Authors: Lonsdale Daria E. , Monteiro Michael J.
Published: September 2011

We demonstrated the synthesis of miktoarm star block copolymers of AB, AB2, and A2B, in which block A consisted of linear poly(tert‐butyl acrylate) (PtBA) and block B consisted of cyclic polystyrene. These structures were produced using the atom transfer radical polymerization to make telechelic polymers that, after modification, were further coupled together by copper‐catalyzed “click” reactions with high coupling efficiency. Deprotection of PtBA to poly(acrylic acid) (PAA) afforded amphiphilic miktoarm structures that when micellized in water gave vesicle morphologies when the block length of PAA was 21 units. Increasing the PAA block length to 46 units produced spherical core‐shell micelles. AB2 miktoarm stars packed more densely into the core compared to its linear counterpart (i.e., a four times greater aggregation number with approximately the same hydrodynamic diameter), resulting in the PAA arms being more compressed in the corona and extending into the water phase beyond its normal Gaussian chain conformation. These results show that the cyclic structure attached to an amphiphilic block has a significant influence on increasing the aggregation number through a greater packing density. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011.
Preparation of phosphinated bisphenol from acid‐fragmentation of 1,1,1‐tris(4‐hydroxyphenyl)ethane and its application in high‐performance cyanate esters
Authors: Lin Ching Hsuan , Lin Hung Tse , Tian Yu Wei , Dai Shenghong A. , Su Wen Chiung
Published: September 2011

We reveal a route for the preparation of phosphinated bisphenol, 1,1‐bis(4‐hydroxyphenyl)‐1‐(6‐oxido‐6H‐dibenz  <1,2> oxaphosphorin‐6‐yl)ethane (2), via a one‐pot reaction of 1,1,1‐tris(4‐hydroxyphenyl)ethane and 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene 10‐oxide (DOPO) in the catalysis of p‐toluenesulfonic acid. A two‐step reaction mechanism, acid‐fragmentation of 1,1,1‐tris(4‐hydroxyphenyl)ethane followed by nucleophilic addition of DOPO, is proposed for the synthesis. Based on (2), a dicyanate ester derivative, 1,1‐bis(4‐cyanatophenyl)‐1‐(6‐oxido‐6H‐dibenz  <1,2> oxaphosphorin‐6‐yl)ethane (3) was prepared and co‐cured with a commercially available dicyanate ester, the dicyanate ester of bisphenol A (BACY). Experimental data show that incorporating (3) into BACY enhances the flame retardancy and dielectric properties with little penalty to the thermal properties. A thermoset with Tg 274 °C, coefficient of thermal expansion (CTE) 49 ppm/°C, Dk 3.04 (1 GHz), Td (5%,) N2: 435 °C, air: 424 °C, and UL‐94 V‐0 rating can be achieved via this approach. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011.
Pi‐conjugated chain extenders for the synthesis of optoelectronic segmented polyurethanes
Authors: Harvey Christopher P. , Tovar John D.
Published: September 2011

The optical properties of mechanochromic materials change under mechanical stress. Segmented polyurethanes are elastomers composed of amorphous, saturated chain soft segments, and rigid pi‐conjugated hard domains. Within aggregates of hard domains pi–pi interactions may form and result in perturbation of the optoelectronic properties of the system. Disruption and restoration of these electronic interactions within the material may lead to observable mechanochromic response. A series of oligothiophene diols and diamines, as well as a naphthalene diimide diol, have been synthesized for incorporation into the hard domains of segmented polyurethanes and polyureas using long poly(tetramethylene oxide) chains as soft segments. The resulting polymers were evaluated to determine their extent of polymerization and their thermal stability. The optical properties of the materials were studied in solution and as thin films. Where possible the electrochemical properties of the polymers were also explored. The length of the soft segment chains in the segmented polyurethanes hindered electronic coupling of hard domains. Future work involving smaller, more solubilizing soft segments may allow for easier material characterization and mechanochromic response. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011.
TREN versus Me6‐TREN as ligands in SET‐LRP of methyl acrylate
Authors: Nguyen Nga H. , Levere Martin E. , Percec Virgil
Published: September 2011

The commercially available tris(2‐aminoethyl)amine (TREN) was used as ligand to mediate the single‐electron transfer‐living radical polymerization (SET‐LRP) of methyl acrylate in dimethyl sulfoxide initiated with the bifunctional initiator bis(2‐bromopropionyl)ethane and catalyzed by both nonactivated and activated Cu(0) wire. A comparative study between TREN and tris(2‐dimethylaminoethyl)amine (Me6‐TREN) ligand, that is more commonly used in SET‐LRP, demonstrated that TREN provided a slower polymerization but the chain‐ends functionality of the resulting bifunctional poly(methyl acrylate) was near quantitative and comparable to that obtained when Me6‐TREN was used as a ligand. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012.
Decoupling the effects of crystallinity and orientation on the shear piezoelectricity of polylactic acid
Authors: Lovell Conrad S. , Fitz‐Gerald James M. , Park Cheol
Published: September 2011

Shear piezoelectricity has been shown to be linearly proportional to the product of polymer crystallinity and orientation. However, investigations concerning the singular and cumulative effects of these parameters are incomplete since these studies relied exclusively on using orientation to alter crystallinity. In this research, polylactic acid (PLA) samples were fabricated by a dual drawing/annealing process to expand the investigation into the relationship between crystallinity, orientation, and shear piezoelectricity. The results of this study show for the first time that PLA shear piezoelectricity possesses a stronger relationship with the product of crystallinity and orientation than either of these parameters individually. However, this research also shows that processing of PLA for shear piezoelectric applications should focus only on achieving large degrees of orientation, which will inherently lead to increases in crystallinity as well. This approach will optimize PLA's shear sensing capabilities while avoiding certain detrimental effects, specifically embrittlement and a reversal of polymer chain orientation, which can occur during annealing. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 1555–1562, 2011