bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and characterization of biodegradable crosslinked polymers from 5‐hydroxylevulinic acid and α,ω‐diols
Authors: Zhang Yan , Wu Linbo , Li Bo‐Geng
Published: May 2010

Novel biodegradable chemically crosslinked polymers, poly(5‐hydroxylevulinic acid‐co‐α,ω‐diol)s (PHLA‐diols), were synthesized from 5‐hydroxylevulinic acid and α,ω‐diols and characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, and dynamic mechanical analysis. The gel content, swelling ratio, tensile properties, and hydrolytic degradation behaviors were also measured and assessed. The glass‐transition temperature of the PHLA‐diols could be adjusted within a wide range (−50 to 30°C) by the type and feed ratio of the diol. Because of the low glass‐transition temperature and crosslink structure, they exhibited certain elastic properties. The tensile modulus, strength, and elongation at break measured at 37°C were 1.4–6.3 MPa, 0.8–1.6 MPa, and 10–25%, respectively. These polymers could be hydrolytically degraded. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Thermal bonding of nonwovens as simulated by polypropylene films: Effect of time, temperature, and molecular weight
Authors: Michielsen Stephen , Jain Siddharth
Published: May 2010

Many nonwoven fabrics are made by melt spinning semicrystalline fibers followed by thermal bonding using heated calendar rolls. In this work, we have studied thermal bonding of polypropylene films to simulate bonding of nonwoven fibers. We have tried to relate the thermal bond strengths with the concepts of chain dynamics via interfacial adhesion development at symmetric polymer interfaces. This requires relating the microscopic dynamics of chains with macroscopic interfacial adhesion measurements. It was found that the interfacial bond strength was proportional to the fraction of the crystals melted. This required heating the interfacial region between the polymer layers into the melting region. Bond strengths were also related to process time as t1/2. This dependence is consistent with the literature for reptation, but is also due to the required thermal diffusion to bring the interfacial region to the bonding temperature. Finally, the bond strength is also dependent on the polymer molecular weight as 1/M1/2, which is consistent with forming the bonds via chain reptation, provided that the bonding time is less than the reptation time. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Ligament and bone pathologic abnormalities more frequent in neuropathic joint disease in comparison with degenerative arthritis of the foot and ankle: Implications for understanding rapidly progressive joint degeneration
Authors: Halstead Jill , Bergin Diane , Keenan Anne‐Maree , Madden Julie , McGonagle Dennis
Published: May 2010

Objective

The variable disease progression of osteoarthritis (OA) and the basis for rapid joint deterioration in some subgroups of patients are poorly understood. To explore an anatomic basis for rapidly progressive OA, this observational study compared the magnetic resonance imaging (MRI) patterns of disease between patients with neuropathic joint disease (NJD) and patients with degenerative arthritis of the ankle and foot.

Methods

MR images of the foot and ankle of patients with early NJD (n = 7) and patients with OA (n = 15) were assessed. The anonomized MR images were dichotomously scored by a musculoskeletal radiologist for the presence of the following abnormalities per bone (of a total of 14 bones): cartilage defects, bone cysts, bone marrow edema, fractures, joint debris, joint effusions, tendinopathy, tendinitis, and ligament tears.

Results

Although the degree of cartilage damage and joint cyst formation was comparable between the groups, the degree of ligament tears, or change in MRI signal intensity in the ligaments, was significantly greater in patients with NJD compared with patients with OA (median of 3 tears versus 0, of 14 total bones; P < 0.01). Moreover, in patients with early NJD compared with patients with OA, there was a significantly greater degree of diffuse bone marrow edema (median of 6.5 tarsal bones versus 2 adjacent bones, of 14 total bones; P < 0.01), a greater number of bone fractures (median 4 versus 0; P < 0.01), and more frequent bone debris (median 4.5 versus 0; P = 0.013).

Conclusion

This analysis of NJD in the foot and ankle shows the predominance of bone and ligament abnormalities in NJD compared with the pattern of involvement in OA. These findings highlight the importance of structures other than articular cartilage in OA of the ankle and foot, and suggest that rapid joint degeneration in NJD may be more ligamentogenic or osteogenic in nature.
Umbilical cord mesenchymal stem cell transplantation in severe and refractory systemic lupus erythematosus
Authors: Sun Lingyun , Wang Dandan , Liang Jun , Zhang Huayong , Feng Xuebing , Wang Hong , Hua Bingzhu , Liu Bujun , Ye Shengqin , Hu Xiang , Xu Wenrong , Zeng Xiaofeng , Hou Yayi , Gilkeson Gary S. , Silver Richard M. , Lu Liwei , Shi Songtao
Published: May 2010

Objective

Umbilical cord (UC)–derived mesenchymal stem cells (MSCs) have shown marked therapeutic effects in a number of diseases in animal studies, based on their potential for self‐renewal and differentiation. No data are available on the effectiveness of UC MSC transplantation (MSCT) in human autoimmune disease. This study was undertaken to assess the efficacy and safety of allogeneic UC MSCT in patients with severe and treatment‐refractory systemic lupus erythematosus (SLE).

Methods

We conducted a single‐arm trial that involved 16 SLE patients whose disease was refractory to standard treatment or who had life‐threatening visceral involvement. All of the patients gave consent and underwent UC MSCT. Clinical changes were evaluated before and after transplantation using the SLE Disease Activity Index (SLEDAI), measurement of serum antinuclear antibody (ANA), anti–double‐stranded DNA (anti‐dsDNA) antibody, serum complement C3 and C4, and albumin levels, and assessment of and renal function. Evaluation of potential mechanisms of MSCT effects focused on the percentage of peripheral blood Treg cells and serum levels of cytokines.

Results

From April 2007 to July 2009, a total of 16 patients with active SLE were enrolled and underwent UC MSCT. The median followup time after MSCT was 8.25 months (range 3–28 months). Significant improvements in the SLEDAI score, levels of serum ANA, anti‐dsDNA antibody, serum albumin, and complement C3, and renal function were observed. Clinical remission was accompanied by an increase in peripheral Treg cells and a re‐established balance between Th1‐ and Th2‐related cytokines. Significant reduction in disease activity was achieved in all patients, and there has been no recurrence to date and no treatment‐related deaths.

Conclusion

Our findings indicate that UC MSCT results in amelioration of disease activity, serologic changes, and stabilization of proinflammatory cytokines. These data provide a foundation for conducting a randomized controlled trial of this new therapy for severe and treatment‐refractory SLE.
Peptidylarginine deiminase from Porphyromonas gingivalis citrullinates human fibrinogen and α‐enolase: Implications for autoimmunity in rheumatoid arthritis
Authors: Wegner Natalia , Wait Robin , Sroka Aneta , Eick Sigrun , Nguyen Ky‐Anh , Lundberg Karin , Kinloch Andrew , Culshaw Shauna , Potempa Jan , Venables Patrick J.
Published: May 2010

Objective

To investigate protein citrullination by the periodontal pathogen Porphyromonas gingivalis as a potential mechanism for breaking tolerance to citrullinated proteins in rheumatoid arthritis (RA).

Methods

The expression of endogenous citrullinated proteins was analyzed by immunoblotting of cell extracts from P gingivalis and 10 other oral bacteria. P gingivalis–knockout strains lacking the bacterial peptidylarginine deiminases (PADs) or gingipains were created to assess the role of these enzymes in citrullination. Citrullination of human fibrinogen and α‐enolase by P gingivalis was studied by incubating live wild‐type and knockout strains with the proteins and analyzing the products by immunoblotting and mass spectrometry.

Results

Endogenous protein citrullination was abundant in P gingivalis but lacking in the other oral bacteria. Deletion of the bacterial PAD gene resulted in complete abrogation of protein citrullination. Inactivation of arginine gingipains, but not lysine gingipains, led to decreased citrullination. Incubation of wild‐type P gingivalis with fibrinogen or α‐enolase caused degradation of the proteins and citrullination of the resulting peptides at carboxy‐terminal arginine residues, which were identified by mass spectrometry.

Conclusion

Our findings demonstrate that among the oral bacterial pathogens tested, P gingivalis is unique in its ability to citrullinate proteins. We further show that P gingivalis rapidly generates citrullinated host peptides by proteolytic cleavage at Arg‐X peptide bonds by arginine gingipains, followed by citrullination of carboxy‐terminal arginines by bacterial PAD. Our results suggest a novel model where P gingivalis–mediated citrullination of bacterial and host proteins provides a molecular mechanism for generating antigens that drive the autoimmune response in RA.
Prolonged expression of CD154 on CD4 T cells from pediatric lupus patients correlates with increased CD154 transcription, increased nuclear factor of activated T cell activity, and glomerulonephritis
Authors: Mehta Jay , Genin Anna , Brunner Michael , Scalzi Lisabeth V. , Mishra Nilamadhab , Beukelman Timothy , Cron Randy Q.
Published: May 2010

Objective

To assess CD154 expression in patients with pediatric systemic lupus erythematosus (SLE) and to explore a transcriptional mechanism that may explain dysregulated expression of CD154.

Methods

Cell surface CD154 expression (pre‐ and postactivation) in peripheral blood CD4 T cells from 29 children with lupus and 29 controls matched for age, sex, and ethnicity was examined by flow cytometry. CD154 expression was correlated with clinical features, laboratory parameters, and treatments received. Increased CD154 expression on CD4 T cells from the SLE patients was correlated with CD154 message and transcription rates by real‐time reverse transcription–polymerase chain reaction (RT‐PCR) and nuclear run‐on assays, respectively. Nuclear factor of activated T cell (NF‐AT) transcription activity and mRNA levels in CD4 T cells from SLE patients were explored by reporter gene analysis and real‐time RT‐PCR, respectively.

Results

CD154 surface protein levels were increased 1.44‐fold in CD4 T cells from SLE patients as compared with controls in cells evaluated 1 day postactivation ex vivo. This increase correlated clinically with the presence of nephritis and an elevated erythrocyte sedimentation rate. Increased CD154 protein levels also correlated with increased CD154 mRNA levels and with CD154 transcription rates, particularly at later time points following T cell activation. Reporter gene analyses revealed a trend for increased NF‐AT, but decreased activator protein 1 and similar NF‐κB, activity in CD4 T cells from SLE patients as compared with controls. Moreover, NF‐AT1 and, in particular, NF‐AT2 mRNA levels were notably increased in CD4 T cells from SLE patients as compared with controls.

Conclusion

Following activation, cell surface CD154 is increased on CD4 T cells from pediatric lupus patients as compared with controls, and this increase correlates with the presence of nephritis, increased CD154 transcription rates, and increased NF‐AT activity. These results suggest that NF‐AT/calcineurin inhibitors, such as tacrolimus and cyclosporine, may be beneficial in the treatment of lupus nephritis.
An exploration of the relationships between work task and interactive information search behavior
Authors: Li Yuelin , Belkin Nicholas J.
Published: May 2010

This study explores the relationships between work task and interactive information search behavior. Work task was conceptualized based on a faceted classification of task. An experiment was conducted with six work‐task types and simulated work‐task situations assigned to 24 participants. The results indicate that users present different behavior patterns to approach useful information for different work tasks: They select information systems to search based on the work tasks at hand, different work tasks motivate different types of search tasks, and different facets controlled in the study play different roles in shaping users' interactive information search behavior. The results provide empirical evidence to support the view that work tasks and search tasks play different roles in a user's interaction with information systems and that work task should be considered as a multifaceted variable. The findings provide a possibility to make predictions of a user's information search behavior from his or her work task, and vice versa. Thus, this study sheds light on task‐based information seeking and search, and has implications in adaptive information retrieval (IR) and personalization of IR.
Water‐in‐ionic liquid microemulsion‐based organogels as novel matrices for enzyme immobilization
Authors: Pavlidis Ioannis V. , Tzafestas Kyriakos , Stamatis Haralambos
Published: May 2010

The use of water‐in‐ionic liquid microemulsion‐based organogels (w/IL MBGs) as novel supports for the immobilization of lipase B from Candida antarctica and lipase from Chromobacterium viscosum was investigated. These novel lipase‐containing w/IL MBGs can be effectively used as solid phase biocatalysts in various polar and non‐polar organic solvents or ILs, exhibiting up to 4.4‐fold higher esterification activity compared to water‐in‐oil microemulsion‐based organogels. The immobilized lipases retain their activity for several hours at 70°C, while their half life time is up to 25‐fold higher compared to that observed in w/IL microemulsions. Fourier‐transform infrared spectroscopy data indicate that immobilized lipases adopt a more rigid structure, referring to the structure in aqueous solution, which is in correlation with their enhanced catalytic behavior observed.
Identification of major metabolites in rat urine and plasma of N6‐(4‐hydroxybenzyl) adenine riboside by LC/MS/MS
Authors: Lei Yujia , Wang Li , Cheng Mengchun , Xiao Hongbin
Published: May 2010

N6‐(4‐hydroxybenzyl) adenine riboside, a novel neuroprotective compound found in Gastrodia elata at trace level, is regarded as a potential drug for the treatment of neural degenerative disease. To understand the metabolism of this compound, the metabolites in rat urine and plasma of N6‐(4‐hydroxybenzyl) adenine riboside were analyzed by HPLC‐ESI‐MS/MS after oral administration of this compound. Beside the parent compound, six phase I metabolites and four phase II metabolites in urine were detected by scanning all possible metabolites in extracted ion chromatograms mode. By comparing their product ion spectra and retention times with those of parent compound, these metabolites were identified and proved to be mainly formed via hydrolysis or hydroxylation in phase I, N‐sulfation or N‐glucuronidation in phase II or their combinations. Similarly, the parent compound, one phase I metabolite and two phase II metabolites were also identified in rat plasma. Therefore, the in vivo metabolic pathways of N6‐(4‐hydroxybenzyl) adenine riboside in rat were proposed. Copyright © 2010 John Wiley & Sons, Ltd.
Modellierung der Abscheidung von Staub an einer luftdurchströmten Hecke
Authors: Berteit W. , Schmidt E.
Published: May 2010

Es wird ein Rechenprogramm vorgestellt, das von der Beschreibung der Partikelabscheidung an einem einzelnen Blatt bis zur Berechnung des Fraktionsabscheidegrades einer durch‐ bzw. umströmten, beliebig strukturierten Hecke reicht. Die höchsten Abscheidegrade ergeben sich für kleine Blätter in homogener Anordnung bei gleichmäßiger Durchströmung der Hecke.
The Formation of DNA Photodamage: The Role of Exciton Localization
Authors: Rössle Shaila , Friedrichs Jana , Frank Irmgard
Published: May 2010

The electronic structure during the formation of a cyclobutane pyrimidine dimer (CPD) between two thymine bases is investigated using semi‐empirical and first‐principles approaches. The dimerization of two isolated thymine bases is found to have no barrier or a very small barrier in agreement with previous studies suggesting low photostability of DNA. The well‐known high photostability of DNA can only be explained taking other factors into account. We investigate the role of the exciton location in the particular environment. Different model systems, from isolated thymine bases to an oligonucleotide in aqueous solution, are discussed. Analysis of the frontier orbitals allows one to understand the connection between the location of the exciton, the relative orientation of the thymine bases, and the observed reactivity.
Conformal Surface Coatings to Enable High Volume Expansion Li‐Ion Anode Materials
Authors: Riley Leah A. , Cavanagh Andrew S. , George Steven M. , Jung Yoon Seok , Yan Yanfa , Lee Se‐Hee , Dillon Anne C.
Published: May 2010

An alumina surface coating is demonstrated to improve electrochemical performance of MoO3 nanoparticles as high capacity/high‐volume expansion anodes for Li‐ion batteries. Thin, conformal surface coatings were grown using atomic layer deposition (ALD) that relies on self‐limiting surface reactions. ALD coatings were tested on both individual nanoparticles and prefabricated electrodes containing conductive additive and binder. The coated and non‐coated materials were characterized using transmission electron microscopy, energy‐dispersive X‐ray spectroscopy, electrochemical impedance spectroscopy, and galvanostatic charge/discharge cycling. Importantly, increased stability and capacity retention was only observed when the fully fabricated electrode was coated. The alumina layer both improves the adhesion of the entire electrode, during volume expansion/contraction and protects the nanoparticle surfaces. Coating the entire electrode also allows for an important carbothermal reduction process that occurs during electrode pre‐heat treatment. ALD is thus demonstrated as a novel and necessary method that may be employed to coat the tortuous network of a battery electrode.
The impact of impulse postfix length on the BER performance of IP‐OFDM systems
Authors: Lee Byung Moo , Kim Youngok
Published: May 2010

The impulse postfix OFDM (IP‐OFDM) system exploits the IP, which consists of a high power impulse sample and several zero samples at the end of a zero padded‐OFDM symbol block, to estimate channel impulse response (CIR) in time domain. In this paper, the impact of IP length on the BER performance of the IP‐OFDM system is analyzed. According to the analytic results, the BER performance can be significantly degraded with both a shorter length of IP as well as a longer length of IP than that of the CIR. Thus, an adaptive IP scheme, which adjusts the length of IP adaptively depending on the length of CIR, is proposed to enhance the BER performance of IP‐OFDM systems and its effectiveness is demonstrated by computer simulations. The BER performance of the IP‐OFDM systems with the proposed adaptive scheme is compared with that of the conventional IP‐OFDM system over various modulation schemes. Simulation results show that the IP‐OFDM with the proposed scheme can achieve about 2 dB performance enhancement compared with that of conventional systems at BER=10−2. Copyright © 2010 John Wiley & Sons, Ltd.
Interobserver variability amongst cytopathologists and histopathologists in the diagnosis of neoplastic follicular patterned lesions of thyroid
Authors: Duggal Rajan , Rajwanshi Arvind , Gupta Nalini , Vasishta, Rakesh Kumar
Published: May 2010

The difficulty in correctly identifying follicular lesions/neoplasms (FN) of thyroid is a well recognized fact. The present study was undertaken to study the degree of interobserver variability among cytopathologists and histopathologists in the diagnosis of these lesions. A total of 74 cases were chosen with a cytological diagnosis varying from FN (43 cases), hürthle cell neoplasm (18 cases), neoplasm suspicious of papillary carcinoma (7 cases) and follicular variant of papillary carcinoma (FVPTC) (4 cases) and neoplasm, NOS (2 cases). All these cases were reviewed by a cytopathologist along with surgical follow‐up. In cases of cytohistological discordance, histopathological diagnoses were also reviewed by a histopathologist. The accuracy of initial and reviewed cytology in predicting neoplastic histological outcome was 100%; however 15 cases were over‐diagnosed on initial cytology as FN and on reviewed cytology, 8/15 cases were under‐diagnosed as non‐neoplastic; however still seven cases were over‐diagnosed on reviewed cytology, thereby specificity for neoplastic histological outcome ranging from 50to 68%. The histopathology diagnosis was reviewed and changed in six cases; therefore interobserver agreement among histopathologist is 92% which reduces further indiagnosis of FVPTC, as in two cases diagnosis of follicular adenoma was changed to FVPTC. Neoplastic follicular patterned lesions (FN) pose diagnostic difficulties among pathologists. So, all cases with a cytological diagnosis of FN should be reviewed along with histopathology to minimize interobserver variability and reviewed histopathology should be considered as “gold standard.” Diagn. Cytopathol. 2011;39:235–241. © 2010 Wiley‐Liss, Inc.
Review of Human Immunodeficiency Virus (HIV) and squamous lesions of the uterine cervix
Authors: Pantanowitz Liron , Michelow Pam
Published: May 2010

With heterosexual transmission becoming the primary mode of transmission, more women are being infected with Human Immunodeficiency Virus (HIV). Accrued data from around the world indicate that these HIV‐infected women exhibit higher rates of persistent HPV infection with multiple oncogenic viruses, more abnormal Pap tests, more prevalent cervical intraepithelial neoplasia (CIN) lesions, and aggressive invasive cervical cancer compared with their HIV‐negative counterparts. In countries where HAART was introduced more than a decade ago, HPV‐related disease is increasing among ageing HIV‐positive women. The high rate of cervical disease seen in HIV‐positive women has prompted recommendations for more aggressive surveillance. The best strategy to screen HIV‐infected women, particularly in resource‐poor nations, remains challenging. This article reviews the collective literature regarding HIV and squamous lesions of the cervix and highlights these key issues. Diagn. Cytopathol. 2011;39:65–72. © 2010 Wiley‐Liss, Inc.
Foxo1 regulates marginal zone B‐cell development
Authors: Chen Jing , Limon Jose J. , Blanc Caroline , Peng Stanford L. , Fruman David A.
Published: May 2010

A fundamental component of signaling initiated by the BCR and CD19 is the activation of phosphoinositide 3‐kinase. Downstream of phosphoinositide 3‐kinase, the protein kinase AKT phosphorylates several substrates, including members of the forkhead box subgroup O (Foxo) transcription factor family. Among the Foxo proteins, Foxo1 has unique functions in bone marrow B‐cell development and peripheral B‐cell function. Here, we report a previously unrecognized role for Foxo1 in controlling the ratio of mature B‐cell subsets in the spleen. Conditional deletion of Foxo1 in B cells resulted in an increased percentage of marginal zone B cells and a decrease in follicular (FO) B cells. In addition, Foxo1 deficiency corrected the absence of marginal zone B cells that occurs in CD19‐deficient mice. These findings show that Foxo1 regulates the balance of mature B‐cell subsets and is required for the marginal zone B‐cell deficiency phenotype of mice lacking CD19.
Macrocyclic Receptor Showing Improved PbII/ZnII and PbII/CaII Selectivities
Authors: Ferreirós‐Martínez Raquel , Platas‐Iglesias Carlos , de Blas Andrés , Esteban‐Gómez David , Rodríguez‐Blas Teresa
Published: May 2010

Herein we report on the macrocyclic receptor N,N′‐bis[(6‐carboxy‐2‐pyridyl)methyl]‐1,10‐diaza‐15‐crown‐5 (H2bp15c5) and its coordination properties towards ZnII, CdII, PbII, and CaII. The stability constants of these complexes determined by pH‐potentiometric titration at 25 °C in 0.1 M KNO3 vary in the following order: PbII > CdII >> ZnII > CaII. As a result, bp15c5 presents very important PbII/ZnII and PbII/CaII selectivities. These results are in contrast to those reported for the related receptor derived from 1,7‐diaza‐12‐crown‐4, which provides very similar complex stabilities for ZnII and PbII. The X‐ray crystal structure of [Cd(Hbp15c5)]+ shows heptadentate binding of the ligand to the metal ion, with two oxygen atoms of the macrocyclic unit remaining uncoordinated. The 1H NMR spectra of the complexes formed with PbII, ZnII, and CaII (D2O) show very broad peaks in the region 2–5 ppm, indicating an important degree of flexibility of the crownmoiety in these complexes. On the contrary, the 1H and 13C NMR spectra recorded for the CdII complex are well resolved and could be fully assigned. A detailed conformational investigation using theoretical calculations performed at the DFT (B3LYP) level predict a minimum energy conformation for [Cd(bp15c5)] that is very similar to that observed in the solid state. Analogous calculations performed on the [M(bp15c5)] (M = Zn or Pb) systems predict hexadentate binding of the ligand to these metal ions. In the case of the PbII complex our calculations indicate that the 6s lone pair is stereochemically active, which results in a hemidirected coordination geometry around the metal ion. The minimum energy conformations calculated for the ZnII, CdII, and PbII complexes are compatible with the experimental NMR spectra obtained in D2O solution.
Reaction Medium pH Dependent Existence of MnII Bound [ON] Donor Zwitterionic Chelating Ligand and Self‐Assembly of Hydroxido‐Bridged MnII4 Cluster
Authors: Sarkar Mrinal , Bertolasi Valerio , Ray Debashis
Published: May 2010

A mononuclear MnN4O2 complex with two zwitterionic ligands and a centrosymmetric tetranuclear μ3‐OH‐bridged self‐assembled Mn4 cluster were synthesized and characterized by using the [NO(H)N] ligand HOPhbip [2,6‐bis(phenylmethyliminomethyl)‐4‐methylphenol]. The reaction in MeOH in the presence of NH4SCN and a lower stoichiometry of Mn(OAc)2·4H2O without any added base produces [MnII(HNbip)2(NCS)2]·CH3CN (1·CH3CN). In the presence of NaOH and NH4SCN in MeOH, the cluster [MnII4(μ‐bip)2(μ3‐OH)2(NCS)4] (2), featuring a stepped‐cubane, was obtained through hydroxido‐bridge‐driven dimerization of two μ3‐OH‐bridged [Mn2] fragments derived from 1·CH3CN.
Synthesis, Chirality and Complexation Phenomena of Two Diastereoisomeric Dinuclear Lanthanide(III) Complexes
Authors: Murray Benjamin S. , Parker David , dos Santos Cidália M. G. , Peacock Robert D.
Published: May 2010

Two diastereoisomeric ditopic ligands have been synthesised by linking (SSS)‐heptadentate triamide derivative of cyclen with a central (SS)‐ or (SR)‐1,2‐diphenyl‐1,2‐diaminoethane derivative. Complexes of selected LnIII ions (Ln = Eu, Tb, Yb) have been characterized and circularly polarised luminescence spectra of the Eu systems revealed significant differences, consistent with a change in overall complex chirality associated with the local helicity at the metal centre. Stepwise binding constants for the formation of 1:1 and 2:1 ternary adducts with (S)‐lactate and (S)‐O‐phospho‐tyrosine have been determined by least‐squares analysis of spectral titration data, and emission and 1H NMR spectroscopic data compared with the mononuclear analogue.
Close Proximity Dibenzo[a,c]phenazine–Fullerene Dyad: Synthesis and Photoinduced Singlet Energy Transfer
Authors: Dubey Rajeev K. , Kumpulainen Tatu , Efimov Alexander , Tkachenko Nikolai V. , Lemmetyinen Helge
Published: May 2010

A dibenzo[a,c]phenazine–fullerene (DBPZ‐C60) dyad in which two chromophores are linked in close proximity to each other has been synthesized and studied in detail by optical spectroscopy to explore a new energy donor–acceptor system. The dyad was prepared by Prato reaction between 11‐formyldibenzo[a,c]phenazine and fullerene. 3,5‐Di‐tert‐butylbenzyl group was introduced onto the fulleropyrrolidine unit to achieve adequate solubility of the dyad. A thorough study of the photophysical properties of the dyad and relevant reference compounds, performed by means of steady state and time resolved spectroscopic measurements, has revealed the presence of highly efficient (ca. 98 %) and extremely fast (ken = 5 × 1011 s–1) intramolecular photoinduced singlet–singlet energy‐transfer process from singlet excited state of the DBPZ moiety to fullerene. In both polar and nonpolar environment transduction of singlet excited state energy governs the excited state deactivation, but the efficiency and rate of energy transfer were found to be higher in nonpolar solvents in comparison to polar. The DBPZ singlet excited state decays within 2 and 4.7 ps in toluene andbenzonitrile, respectively, via singlet–singlet energy transfer to produce a fullerene singlet excited state which decays with a life time of 1.5 ns to give a very long‐lived fullerene triplet state as final populated excited state.
Convenient Access to Various 1‐Cyclopropylcyclopropane Derivatives
Authors: de Meijere Armin , Khlebnikov Alexander F. , Sünnemann Hans Wolf , Frank Daniel , Rauch Karsten , Yufit Dmitrii S.
Published: May 2010

1‐Bromo‐1‐cyclopropylcyclopropane (1), which is easily accessible in two steps from methyl cyclopropanecarboxylate, does not form a stable Grignard reagent upon reaction with elemental magnesium, yet it readily undergoes bromine/lithium exchange without rearrangement upon treatment with tert‐butyllithium in diethyl ether/pentane at –78 °C, and the resulting 1‐lithio‐1‐cyclopropylcyclopropane can be trapped with various electrophiles to give the correspondingly 1‐substituted bicyclopropyl derivatives 10 in yields ranging from 38 to over 90 % (13 examples). The (1‐cyclopropylcyclopropyl)boronate 10m, which is also obtained from the 1‐lithio derivative, has been subjected to Suzuki cross couplings with a number of aryl halides to furnish 1‐aryl‐1,1′‐bicyclopropyl compounds 11 (4 examples, 14–50 % yield), predominantly without rearrangement. Further transformations of 1‐cyclopropylcyclopropanecarbaldehyde (10e) have provided 2‐(1‐cyclopropylcyclopropyl)glycine (16), ethyl 3‐(1‐cyclopropylcyclopropyl)acrylate (17), and its cycloadducts with the nitrone 18 and cyclopentadiene 19, albeit the latter only in poor yield.
Organocatalytic Enantioselective Friedel–Crafts Alkylation of Sesamol with Nitro Olefins
Authors: Zhang Hui , Liao Yu‐Hua , Yuan Wei‐Cheng , Zhang Xiao‐Mei
Published: May 2010

A bifunctional chiral thiourea–tertiary amine organocatalyst derived from cinchonine was employed to promote the enantioselective Friedel–Crafts alkylation of sesamol and 2‐substituted sesamols with various aromatic nitro olefins. The reactions proceeded smoothly to provide the corresponding products in good yields (up to 97 %) and good enantioselectivities (up to 90 % ee).
Genomic profile of endometrial tumors depends on morphological subtype, not on tamoxifen exposure
Authors: Fles Renske , Hoogendoorn Wilhelmina E. , Platteel Inge , Scheerman Caroline E. , de Leeuw‐Mantel Gerie , Mourits Marian J. E. , Hollema Harry , van Leeuwen Flora E. , van Boven Hester H. , Nederlof Petra M.
Published: May 2010

Tamoxifen has been a very effective treatment for breast cancer for several decades, however, at the same time increases the risk of endometrial cancer, especially after prolonged exposure. In addition, tamoxifen has been associated with a higher proportion of unfavorable uterine tumor subtypes (carcinosarcomas and serous adenocarcinomas) with worse survival. We investigated whether endometrial tumors, which developed after prolonged tamoxifen treatment for breast cancer, are genetically different from endometrial tumors without preceding tamoxifen exposure. Array CGH was used on archival formalin‐fixed paraffin embedded endometrial tumors to determine genomic aberrations. We compared the genomic profiles of 52 endometrial tumors from breast cancer patients after long‐term (≥2 years) tamoxifen use (endometrioid adenocarcinomas, n = 26; carcinosarcomas, n = 14; and serous adenocarcinomas, n = 12) with endometrial tumors from unexposed breast cancer patients (n = 45). Genomic profiles were correlated with tamoxifen exposure, tumor subtypes, and histopathological characteristics of the endometrial tumors. The common uterine corpus cancers of the endometrioid subtype show few genomic aberrations. Tumors with many genomic aberrations were in general ER‐negative. In contrast, carcinosarcomas and serous adenocarcinomas showed many aberrations; however, they were indistinguishable from each other. Tumors that developed after prolonged tamoxifen use did not show more or different aberrations than unexposed tumors. This was true for all tumor subtypes. Thus, endometrial carcinomas that develop after prolonged tamoxifen use cannot be distinguished from nonusers on basis of their tumor genomic profile. © 2010 Wiley‐Liss, Inc.
Hyperprolactinemia associated with psychotropics—a review
Authors: Madhusoodanan Subramoniam , Parida Suprit , Jimenez Carolina
Published: May 2010

Introduction:

Different classes of psychotropics can cause hyperprolactinemia to varying degrees. Among antipsychotics, typical agents and risperidone are the most frequent and significant offenders. In this review we discuss the pathophysiology, offending medications, assessment and management of hyperprolactinemia.

Methods:

We did a literature review between 1976 and 2008 using PubMed, MEDLINE, PsychINFO and Cochrane database. Search terms used were prolactin, hyperprolactinemia, psychotropics, antipsychotics, typical antipsychotics, atypical antipsychotics, antidepressants and SSRIs.

Results:

Prolactin elevation is more common with antipsychotics than with other classes of drugs. Typical antipsychotics are more prone to cause hyperprolactinemia than atypical agents. Management options include discontinuation of offending medication, switching to another psychotropic, supplementing concurrent hormonal deficiencies and adding a dopamine agonist or aripiprazole.

Conclusion:

Clinicians need to be alert about the potential for hyperprolactinemia and its manifestations with these medications. Prolactin levels need to be monitored and other causes of hyperprolactinemia ruled out in suspected cases. Copyright © 2010 John Wiley & Sons, Ltd.
VEGFR‐2 expression in carcinoid cancer cells and its role in tumor growth and metastasis
Authors: Silva Scott R. , Bowen Kanika A. , Rychahou Piotr G. , Jackson Lindsey N. , Weiss Heidi L. , Lee Eun Y. , Townsend Courtney M. , Evers B. Mark
Published: May 2010

Carcinoid tumors are slow growing and highly vascular neuroendocrine neoplasms that are increasing in incidence. Previously, we showed that carcinoid tumors express vascular endothelial growth factor receptor 2 (VEGFR‐2) in the epithelial compartment of carcinoid tumor sections; yet, its role is not completely understood. The purpose of our study was to: (i) assess the expression of VEGFR‐2 in the novel human carcinoid cell line BON, (ii) to determine the role of PI3K/Akt signaling on VEGFR‐2 expression and (iii) to assess the effect of VEGFR‐2 on BON cell invasion, migration and proliferation. We found that, although VEGFR‐2 is expressed in BON cells, reduction in VEGFR‐2 expression actually enhanced proliferation, invasion, and migration of the BON cell line. Also, expression of VEGFR‐2 was inversely related to PI3K signaling. Carcinoid liver metastases in mice demonstrated decreased VEGFR‐2 expression. Furthermore, the expression of a truncated, soluble form of VEGFR‐2 (sVEGFR‐2), a protein demonstrated to inhibit cell growth, was detected in BON cells. The presence of VEGFR‐2 in the epithelial component of carcinoid tumors and in the BON cell line suggests an alternate role for VEGFR‐2, in addition to its well‐defined role in angiogenesis. The expression of sVEGFR‐2 may explain the inverse relationship between VEGFR‐2 expression and PI3K/Akt signaling and the inhibitory effect VEGFR‐2 has on BON cell proliferation, migration and invasion.
Aboard transthyretin: From transport to cleavage
Authors: Liz Márcia A. , Mar Fernando M. , Franquinho Filipa , Sousa Mónica M.
Published: May 2010

Transthyretin (TTR) is a plasma and cerebrospinal fluid protein mainly recognized as the transporter of thyroxine (T4) and retinol. Mutated TTR leads to familial amyloid polyneuropathy, a neurodegenerative disorder characterized by TTR amyloid deposition particularly in peripheral nerves. Beside its transport activities, TTR is a cryptic protease and participates in the biology of the nervous system. Several studies have been directed at finding new ligands of TTR to further explore the biology of the protein. From the identified ligands, some were in fact TTR protease substrates. In this review, we will discuss the existent information concerning TTR ligands/substrates. © 2010 IUBMB IUBMB Life, 62(6): 433–439, 2010
Transmission infrared spectroscopy of whole blood – complications for quantitative analysis from leucocyte adhesion during continuous monitoring
Authors: Vahlsing Thorsten , Damm Uwe , Radhakrishna Kondepati Venkata , Leonhardt Steffen , Brendel Mathias D. , Wood Bayden R. , Heise H. Michael
Published: May 2010

Infrared spectroscopy has been applied to analyse glucose and cellular components in whole blood with the aim of developing an online clinical diagnostic and monitoring modality. Leucocyte adsorption onto the CaF2 windows was observed over a period of several hours under continuous blood flow using a transmission cell of 30 μm path length. This build‐up of cellular material on the windows is responsible for diminishing the sample path length under the flow conditions chosen. The adsorption dynamics have been characterised and their impact on glucose monitoring is reported. For short‐term monitoring (<2 hours) a standard error of prediction of 11 mg/dL with human citrated blood samples from three different subjects was achieved. Furthermore, the leucocyte build‐up was also reported for porcine EDTA blood monitoring. Consequences and testing opportunities with regard to the first stages in the immune cell reaction to the exposure of body‐foreign materials to anticoagulated whole blood are discussed. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A theoretical study on the catalytic mechanism of Mus musculus adenosine deaminase
Authors: Wu Xian‐Hui , Zou Guo‐Lin , Quan Jun‐Min , Wu Yun‐Dong
Published: May 2010

The catalytic mechanism of Mus musculus adenosine deaminase (ADA) has been studied by quantum mechanics and two‐layered ONIOM calculations. Our calculations show that the previously proposed mechanism, involving His238 as the general base to activate the Zn‐bound water, has a high activation barrier of about 28 kcal/mol at the proposed rate‐determining nucleophilic addition step, and the corresponding calculated kinetic isotope effects are significantly different from the recent experimental observations. We propose a revised mechanism based on calculations, in which Glu217 serves as the general base to abstract the proton of the Zn‐bound water, and the protonated Glu217 then activates the substrate for the subsequent nucleophilic addition. The rate‐determining step is the proton transfer from Zn‐OH to 6‐NH2 of the tetrahedral intermediate, in which His238 serves as a proton shuttle for the proton transfer. The calculated kinetic isotope effects agree well with the experimental data, and calculated activation energy is also consistent with the experimental reaction rate. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2010
Accurate prediction of enthalpies of formation for a large set of organic compounds
Authors: Liu Cun‐Xi , Wang Hai‐Xia , Li Ze‐Rong , Zhou Chong‐Wen , Rao Han‐Bing , Li Xiang‐Yuan
Published: May 2010

This article describes a multiparameter calibration model, which improves the accuracy of density functional theory (DFT) for the prediction of standard enthalpies of formation for a large set of organic compounds. The model applies atom based, bond based, electronic, and radical environmental correction terms to calibrate the calculated enthalpies of formation at B3LYP/6‐31G(d,p) level by a least‐square method. A diverse data set of 771 closed‐shell compounds and radicals is used to train the model. The leave‐one‐out cross validation squared correlation coefficient q2 of 0.84 and squared correlation coefficient r2 of 0.86 for the final model are obtained. The meanabsolute error in enthalpies of formation for the dataset is reduced from 4.9 kcal/mol before calibration to 2.1 kcal/mol after calibration. Five‐fold cross validation is also used to estimate the performance of the calibration model and similar results are obtained. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2010
The symptom checklist‐revised (SCL‐90‐R) is able to discriminate between simulation and fibromyalgia
Authors: Torres Xavier , Bailles Eva , Collado Antonio , Taberner Joan , Gutierrez Fernando , Peri Josep‐Maria , Arias Anna , Fullana Miquel‐Angel , Valdes Manuel
Published: May 2010

This study assessed the ability of the Symptom Checklist‐Revised (SCL‐90‐R) to discriminate between two groups of fibromyalgia patients (those who were about to begin a treatment including the explicit aim of returning to work and those who were initiating a legal procedure to obtain permanent disability compensation) and two groups of healthy volunteers (medical students and psychology graduates), who were asked to produce a symptomatic resemblance to a chronic pain disorder. Logistic regression analyses were applied to the SCL‐90‐R subscales and individual probabilistic indices of simulation were calculated. Results showed that the SCL‐90‐R was able to discriminate between healthy subjects and both groups of patients with a high sensitivity and specificity. The individual indices of simulation, which might be more useful in clinical practice than the comparison of the SCL‐90‐R profiles, also showed an appropriate level of accuracy. Inc. J Clin Psychol: 66: 1–17, 2010.
Functional mimicry of the acetylated C‐terminal tail of p53 by a SUMO‐1 acetylated domain, SAD
Authors: Cheema Amrita , Knights Chad D. , Rao Mahadev , Catania Jason , Perez Ricardo , Simons Brigitte , Dakshanamurthy Sivanesan , Kolukula Vamsi K. , Tilli Maddalena , Furth Priscilla A. , Albanese Christopher , Avantaggiati Maria Laura
Published: May 2010

The ubiquitin‐like molecule, SUMO‐1, a small protein essential for a variety of biological processes, is covalently conjugated to many intracellular proteins, especially to regulatory components of the transcriptional machinery, such as histones and transcription factors. Sumoylation provides either a stimulatory or an inhibitory signal for proliferation and for transcription, but the molecular mechanisms by which SUMO‐1 achieves such versatility of effects are incompletely defined. The tumor suppressor and transcription regulator p53 is a relevant SUMO‐1 target. Particularly, the C‐terminal tail of p53 undergoes both sumoylation and acetylation. While the effects of sumoylation are still controversial, acetylation modifies p53 interaction with chromatin embedded promoters, and enforces p53 apoptotic activity. In this study, we show that the N‐terminal region of SUMO‐1 might functionally mimic this activity of the p53 C‐terminal tail. We found that this SUMO‐1 domain possesses similarity with the C‐terminal acetylable p53 tail as well as with acetylable domains of other transcription factors. SUMO‐1 is, indeed, acetylated when conjugated to its substrates and to p53. In the acetylable form SUMO‐1 tunes the p53 response by modifying p53 transcriptional program, by promoting binding onto selected promoters and by favoring apoptosis. By contrast, when non‐acetylable, SUMO‐1 enforces cell‐cycle arrest and p53 binding to a different sets of genes. These data demonstrate for the first time that SUMO‐1, a post‐translational modification is, in turn, modified by acetylation. Further, they imply that the pleiotropy of effects by which SUMO‐1 influences various cellular outcomes and the activity of p53 depends upon its acetylation state. J. Cell. Physiol. 225: 371–384, 2010. © 2010 Wiley‐Liss, Inc.
Tuning of the characteristics of Au nanoparticles produced by solid target laser ablation into water by changing the irradiation parameters
Authors: Kalyva Maria , Bertoni Giovanni , Milionis Athanasios , Cingolani Roberto , Athanassiou Athanassia
Published: May 2010

We report the production of Au nanoparticles with different average sizes and size distributions, by laser ablation of a solid Au target into pure deionized water. Tuning laser parameters such as pulse duration, energy, and wavelength is possible to tune the size and the size distributions of the produced nanoparticles into the liquid. We demonstrate the possibility of production of highly monodispersed colloidal solutions, in which the average nanoparticle size ranges from 3 to 10 nm, using laser pulses of ns duration. Laser ablation using fs laser pulses can also produce very small nanoparticles, although a small population of bigger nanoparticles is always present. Low and high‐resolution transmission electron microscopy (TEM), in combination with UV–Vis spectroscopy have been employed for the characterization of our samples. Microsc. Res. Tech. 73:937–943, 2010. © 2010 Wiley‐Liss, Inc.
Application of 1,3‐azomethine ylides derived from α‐dicarbonyl compounds and L‐proline to the synthesis of pyrrolizidines
Authors: Felluga Fulvia , Forzato Cristina , Nitti Patrizia , Pitacco Giuliana , Valentin Ennio , Zangrando Ennio
Published: May 2010

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The reaction of 2,3‐butanedione, ethyl pyruvate, and phenylglyoxal with β‐nitrostyrene and L‐proline in isopropanol at room temperature gives substituted pyrrolizidines, as a result of one‐pot three component reaction. On the contrary, a spiropyrrolizidine is formed from 1,2‐cyclohexanedione only when the reaction is carried out in refluxing isopropanol, whereas at room temperature, incorporation of the amine component into the products is not observed and bicyclo[3.2.1]octanones are formed, as a result of a tandem Michael‐Henry reaction. In this latter case, L‐proline acts as an organocatalyst, although with modest enantioselectivity. The stereochemistry of the products is given and the mechanism of formation of products is postulated, on the basis of stereochemical arguments. J. Heterocyclic Chem., (2010).
Multi‐technique investigation of archaeological pottery from Parma (Italy)
Authors: Bersani D. , Lottici P. P. , Virgenti S. , Sodo A. , Malvestuto G. , Botti A. , Salvioli‐Mariani E. , Tribaudino M. , Ospitali F. , Catarsi M.
Published: May 2010

A ceramic factory with at least three kilns, active from the 14th century until the 17th century, was recently found close to the city walls of Parma (Italy). A series of measurements by different techniques was performed on pottery fragments belonging to the first and last production period. Micro‐Raman spectroscopy and scanning electron microscopy–energy dispersive spectroscopy were used to study the glazes and the painting materials, while time‐of‐flight neutron diffraction and X‐ray diffraction were used to characterize the ceramic bodies. The bodies are mainly composed by quartz, diopside, Na‐ and K‐rich alkali feldspars, gehlenite, calcite, and silica‐alumina glass; the red coloration is due to hematite. The glazes were obtained using a lead‐silica glass, with a fictive temperature of about 600 °C. The main pigments were identified. The ceramics were produced from illitic calcareous clays and annealed in an oxidizing atmosphere at an estimated temperature of 900–1000 °C. Different amounts of magnesium in ceramics of the 14th and 17th century suggest the use of different quarries. The white pigment in the 17th century ceramics, showing the Raman spectrum of nearly pure anatase, is due to a titanium‐bearing clay. Copyright © 2010 John Wiley & Sons, Ltd.