bluuebunny/crossref_metadata_2025_split huggingface dataset:
Flow injection determination of diclofenac sodium based on its sensitizing effect on the chemiluminescent reaction of acidic potassium permanganate–formaldehyde
Authors: Song Jingjing , Sun Pulv , Ji Zhongling , Li Jianguo 
Published: May 2014

AbstractA sensitive and simple chemiluminescent (CL) method for the determination of diclofenac sodium has been developed by combining the flow injection technique and its sensitizing effect on the weak CL reaction between formaldehyde and acidic potassium permanganate. A calibration curve is constructed for diclofenac sodium under optimized experimental parameters over the range 0.040–5.0 µg/mL and the limit of detection is 0.020 µg/mL (3σ). The inter‐assay relative standard deviation for 0.040 µg/mL diclofenac sodium (n = 11) is 2.0%. This method is rapid, sensitive, simple, and shows good selectivity and reproducibility. The proposed method has been successfully applied to the determination of the studied diclofenac sodium in pharmaceutical preparations with satisfactory results. Furthermore, the possible mechanism for the CL reaction has been discussed in detail on the basis of UV and CL spectra. Copyright © 2014 John Wiley & Sons, Ltd.
Development of new antiatherosclerotic and antithrombotic drugs utilizing F11 receptor (F11R/JAM‐A) peptides
Authors: Babinska A. , Clement C. C. , Swiatkowska M. , Szymanski J. , Shon A. , Ehrlich Y. H. , Kornecki E. , Salifu M. O. 
Published: May 2014

ABSTRACTPeptides with enhanced resistance to proteolysis, based on the amino acid sequence of the F11 receptor molecule (F11R, aka JAM‐A/Junctional adhesion molecule‐A), were designed, prepared, and examined as potential candidates for the development of anti‐atherosclerotic and anti‐thrombotic therapeutic drugs. A sequence at the N‐terminal of F11R together with another sequence located in the first Ig‐loop of this protein, were identified to form a steric active‐site operating in the F11R‐dependent adhesion between cells that express F11R molecules on their external surface. In silico modeling of the complex between two polypeptide chains with the sequences positioned in the active‐site was used to generate peptide‐candidates designed to inhibit homophilic interactions between surface‐located F11R molecules. The two lead F11R peptides were modified with D‐Arg and D‐Lys at selective sites, for attaining higher stability to proteolysis in vivo. Using molecular docking experiments we tested different conformational states and the putative binding affinity between two selected D‐Arg and D‐Lys‐modified F11R peptides and the proposed binding pocket. The inhibitory effects of the F11R peptide 2HN‐(dK)‐SVT‐(dR)‐EDTGTYTC‐CONH2 on antibody‐induced platelet aggregation and on the adhesion of platelets to cytokine‐inflammed endothelial cells are reported in detail, and the results point out the significant potential utilization of F11R peptides for the prevention and treatment of atherosclerotic plaques and associated thrombotic events. © 2014 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 102: 322–334, 2014.
Highly sensitive LC‐MS/MS method for determination of galantamine in rat plasma: application to pharmacokinetic studies in rats
Authors: Suresh P. S. , Mullangi Ramesh , Sukumaran Sathesh Kumar 
Published: May 2014

ABSTRACTA rapid and highly sensitive assay method has been developed and validated for the estimation of galantamine (GLM) in rat plasma using liquid chromatography coupled to tandem mass spectrometry with electrospray ionization in the positive‐ion mode. The assay procedure involves a simple liquid–liquid extraction of GLM and phenacetin (internal standard, IS) from rat plasma using acetonitrile. Chromatographic separation was achieved with 0.2% formic acid:acetonitrile (50:50, v/v) at a flow rate of 0.60 mL/min on an Atlantis dC18 column with a total run time 2.5 min. The MS/MS ion transitions monitored were 288.10 → 213.10 for GLM and 180.10 → 110.10 for IS. Method validation was performed as per United States Food and Drug Administration guidelines and the results met the acceptance criteria. The lower limit of quantitation achieved was 0.12 ng/mL and linearity was observed from 0.12 to 525 ng/mL. The intra‐ and inter‐day precision were in the ranges of 4.73–11.7 and 5.83–8.64%, respectively. This novel method has been applied to a pharmacokinetic study in rats. Copyright © 2014 John Wiley & Sons, Ltd.
Distribution study of tryptanthrin in rat tissues by HPLC and its relationship with meridian tropism of indigo naturalis in traditional Chinese medicine
Authors: Zhang Ning , Hua Ying , Wang Cuiling , Sun Yanni , Wang Zheng , Liu Zhulan , Liu Jianli 
Published: May 2014

ABSTRACTThe aim of the present study is to characterize the distribution of tryptanthrin (TRYP) in rat tissues following oral administration at a dose of 100 mg/kg and its relationship with meridian tropism (MT) of indigo naturalis (IN) in traditional Chinese medicine (TCM). For quantitative analysis in biological samples, a sensitive, inexpensive and accurate high‐performance liquid chromatographic method was developed and validated with 2‐hydroxy acetophenone as internal standard, a Shimadzu C18 column and water–acetonitrile (55:45, v/v) as mobile phase. Acceptable intra‐day and inter‐day precision at high, medium and low concentration was acquired with RSD ranging from 0.87 to 5.22% and from 1.25 to 6.47%, respectively. Good assay and extraction recoveries were obtained with a single and relatively fast step to precipitate protein. The extraction recovery of TRYP ranged from 87.5 to 94.5 %. TRYP concentration was highest in the liver and remained for a much longer time than in other tissues. It could also be detected in kidney, lung, heart and spleen, but not in brain under the experimental conditions. The results confirmed the traditional knowledge of TCM that MT of IN belongs to the liver meridians and demonstrated that TRYP is one of the active constituents of the MT of IN. Copyright © 2014 John Wiley & Sons, Ltd.
High CD49f expression is associated with osteosarcoma tumor progression: a study using patient‐derived primary cell cultures
Authors: Penfornis Patrice , Cai David Z. , Harris Michael R. , Walker Ryan , Licini David , Fernandes Joseph D. A. , Orr Griffin , Koganti Tejaswi , Hicks Chindo , Induru Spandana , Meyer Mark S. , Khokha Rama , Barr Jennifer , Pochampally Radhika R. 
Published: May 2014

AbstractOverall prognosis for osteosarcoma (OS) is poor despite aggressive treatment options. Limited access to primary tumors, technical challenges in processing OS tissues, and the lack of well‐characterized primary cell cultures has hindered our ability to fully understand the properties of OS tumor initiation and progression. In this study, we have isolated and characterized cell cultures derived from four central high‐grade human OS samples. Furthermore, we used the cell cultures to study the role of CD49f in OS progression. Recent studies have implicated CD49f in stemness and multipotency of both cancer stem cells and mesenchymal stem cells. Therefore, we investigated the role of CD49f in osteosarcomagenesis. First, single cell suspensions of tumor biopsies were subcultured and characterized for cell surface marker expression. Next, we characterized the growth and differentiation properties, sensitivity to chemotherapy drugs, and anchorage‐independent growth. Xenograft assays showed that cell populations expressing CD49fhi/CD90lo cell phenotype produced an aggressive tumor. Multiple lines of evidence demonstrated that inhibiting CD49f decreased the tumor‐forming ability. Furthermore, the CD49fhi/CD90lo cell population is generating more aggressive OS tumor growth and indicating this cell surface marker could be a potential candidate for the isolation of an aggressive cell type in OSs.
Tumor necrosis factor‐α regulates matrix metalloproteinase‐2 expression and cell migration via ERK pathway in rat glomerular mesangial cells
Authors: Wang Yuebing , Li Ming , Xu Yang , He Ningning , Leng Liang , Li Zongjin 
Published: May 2014

AbstractMesangial cells (MCs), vascular smooth muscle‐derived cells, contribute to glomerular injury by generating a number of cytokines such as tumor necrosis factor‐α (TNF‐α). Matrix metalloproteinases (MMPs), regulated by various stimuli, are important in remodeling of glomerular ECM, which leads to a number of renal diseases. We investigated whether TNF‐α participated in the regulation of MMPs and explored signal pathways involved in TNF‐α‐induced MMPs expression in rat glomerular MCs. Western blot and RT‐qPCR results showed that treatment with TNF‐α significantly increased the expression of MMP‐2, but not MMP‐9 at both protein and mRNA levels in rat glomerular MCs. The extracellular signal‐regulated kinase (ERK) and nuclear factor‐kappaB (NF‐κB) signal pathways were activated by TNF‐α. Moreover, the activation of NF‐κB pathway in rat MCs was effectively inhibited by PD98059, specific inhibitor of ERK, suggesting a role for ERK in regulating NF‐κB function. PD98059 or NF‐κB signal pathway selective inhibitor Bay 11‐7082 effectively blocked TNF‐α‐induced expression of MMP‐2 in rat MCs, as determined by gene and protein expression. C‐jun N‐terminal kinase (JNK) signal pathway had no effect on TNF‐α‐induced expression of MMP‐2, even though it was also activated by TNF‐α in rat MCs. Furthermore, TNF‐α could induce the cell migration of rat MCs, whereas ERK signal pathway specific inhibitor PD98059 compromised the cell migration triggered by TNF‐α. Thus, TNF‐α upregulates the expression of MMP‐2 via activation of ERK‐dependent NF‐κB pathway in rat MCs, which may contribute to the cell migration of rat MCs.
Comparative study of directional differentiation of human and mouse embryonic stem cells into cardiomyocytes
Authors: Mu Junsheng , Li Xianshuai , Yuan Shumin , Zhang Jianqun , Bo Ping 
Published: May 2014

AbstractThis comparative study investigates the method, efficiency, and anti‐hypoxic ability of cardiomyocytes, directionally induced from human (h) and mouse (m) embryonic stem cells (ESCs). hESCs were induced into cardiomyocytes by suspension culture, without inducers, or adherent culture using the inducers activin A and BMP4. mESCs were induced into cardiomyocytes by hanging‐drop method, without inducers or induced with vitamin C. All four methods successfully induced ESCs to differentiate into cardiomyocytes. There was a significant difference between groups with and without inducers. A significant difference was found between mESC and hESC groups with inducers. The average beating frequency of cardiomyocytes differentiated from hESC was lower than cardiomyocytes differentiated from mESC, while the average beating frequency of cardiomyocytes differentiated from the same cell line, despite different culture methods, did not differ. Beating cardiomyocytes of each group were positive for cTnT staining. Spontaneous action potentials of beating cardiomyocytes were detected by patch‐clamp experiments in each group. Different apoptotic ratios were detected in beating cardiomyocytes in each group and the difference between cardiomyocytes induced from mESCs and hESCs was statistically significant. The differentiation efficiencies in the groups without inducers were significantly higher than those without inducers. The induction of mESCs was more simple and efficient compared with hESCs. Without the presence of other protective factors, the anti‐hypoxic ability of cardiomyocytes induced from hESCs was stronger and the beating times were longer in vitro compared with mESCs.
Measuring mechanical properties in cells: three easy methods for biologists
Authors: Bonakdar Navid , Schilling Achim , Lennert Pablo , Spörrer Marina , Gerum Richard C. , Alonso José Luis , Goldmann Wolfgang H. 
Published: May 2014

AbstractThe mechanism by which cells sense stresses and transmit them throughout the cytoplasm and the cytoskeleton (CSK) and by which these mechanical signals are converted into biochemical signaling responses is not clear. Specifically, there is little direct experimental evidence on how intracellular CSK structural elements in living cells deform and transmit stresses in response to external mechanical forces. Existing theories have invoked various biophysical and biochemical mechanisms to explain how cells spread, deform, divide, move, and change shape in response to mechanical inputs, but rigorous tests in cells are lacking. The lack of data and understanding is preventing the identification of mechanisms and sites of mechano‐regulation in cells. Here, we introduce and describe three unique and easy methods for biologists to determine mechanical properties and signaling events in cells.
Stimulatory effect of HGF‐overexpressing adipose tissue‐derived mesenchymal stem cells on thymus regeneration in a rat thymus involution model
Authors: Jung Woo‐Sung , Han Sei‐Myoung , Kim Sung‐Min , Kim Mi‐Eun , Lee Jun‐Sik , Seo Kyoung‐Won , Youn Hwa‐Young , Lee Hee‐Woo 
Published: May 2014

AbstractThe thymus is the central lymphoid organ providing a unique and essential microenvironment for T‐cell precursor development into mature functionally competent T‐lymphocytes. Thus, it is important to develop the strategies for enhancing thymic regeneration from involution induced by a variety of clinical treatments and conditions. Hepatocyte growth factor (HGF) promotes proliferation in a variety of cell types. We have used stem cell‐based HGF gene therapy to enhance regeneration from acute thymic involution. HGF‐overexpressing human adipose tissue‐derived mesenchymal stem cells (HGF‐hATMSCs) were generated by liposomal transfection with the pMEX expression vector, constructed by inserting the HGF gene. Significantly increased HGF expression in these cells was confirmed by reverse transcription‐polymerase chain reaction and an enzyme‐linked immunosorbent assay. HGF produced by HGF‐hATMSCs enhanced the proliferation of a mouse thymic epithelial cell line and the expression of interleukin‐7 in vitro. We also examined the effect of HGF‐hATMSCs on thymic regeneration in rats with acute thymic involution. Significant increases in thymus size and weight, as well as the number of thymocytes (especially, early thymocyte progenitors), were seen in the HGF‐hATMSCs‐treated rats compared to saline‐treated control animals. A stimulatory effect of HGF‐hATMSCs on thymic regeneration has therefore been shown, highlighting the clinical value of HGF‐hATMSCs for treating thymic involution.
Tight and Selective Caging of Chloride Ions by a Pseudopeptidic Host
Authors: Martí Inés , Bolte Michael , Burguete M. Isabel , Vicent Cristian , Alfonso Ignacio , Luis Santiago V. 
Published: May 2014

AbstractThe selective molecular recognition of chloride versus similar anions is a continuous challenge in supramolecular chemistry. We have designed and prepared a simple pseudopeptidic cage (1 a) that defines a cavity suitable for the tight encapsulation of chloride. The interaction of the protonated form of 1 a with different inorganic anions was studied in solution by 1H NMR spectroscopy and ESI‐MS, and in the solid state by X‐ray diffraction. The solution binding data showed that the association constants of 1 a to chloride are more than two orders of magnitude higher than to any other tested inorganic anion. Remarkably, 1 a displayed a high selectivity for chloride over other closely related halides such as bromide (selectivity=111), iodide (selectivity=719), and fluoride (selectivity >1000). Binding experiments (1H NMR spectroscopy and ESI‐MS) suggested that 1 a has a high‐affinity (inner) binding site and an additional low‐affinity (external) binding site. The supramolecular complexes with F−, Cl−, and Br− have been also characterized by the X‐ray diffraction of the corresponding [1 a⋅nHX] crystalline salts. The structural data show that the chloride anion is tightly encapsulated within the host, in a binding site defined by a very symmetric array of electrostatic H‐bonds. For the fluoride salt, the size of the cage cavity is too large and is occupied by a water molecule, which fits inside the cage efficiently competing with F−. In the case of the bigger bromide, the mismatch of the anion inside the cage caused a geometrical distortion of the host and thus a large energetic penalty for the interaction. This minimalistic pseudopeptidic host represents a unique example of the construction of a simple well‐defined binding pocket that allows the highly selective molecular recognition of a challenging substrate.
New Polydentate Trimethylsilyl Chalcogenide Reagents for the Assembly of Polyferrocenyl Architectures
Authors: Fard Mahmood Azizpoor , Khalili Najafabadi Bahareh , Hesari Mahdi , Workentin Mark S. , Corrigan John F. 
Published: May 2014

AbstractA series of polychalcogenotrimethylsilane complexes Ar(CH2ESiMe3)n, (Ar=aryl; E=S, Se; n=2, 3, and 4) can be prepared from the corresponding polyorganobromide and M[ESiMe3] (M=Na, Li). These represent the first examples of the incorporation of such a large number of reactive ESiMe3 moieties onto an organic molecular framework. They are shown to be convenient reagents for the preparation of the polyferrocenylseleno‐ and thioesters from ferrocenoyl chloride. The synthesis, structures, and spectroscopic properties of the new silyl chalcogen complexes 1,4‐(Me3SiECH2)2(C6Me4) (E=S, 1; E=Se, 2), 1,3,5‐(Me3SiECH2)3(C6Me3) (E=S, 3; E=Se, 4) and 1,2,4,5‐(Me3SiECH2)4(C6H2) (E=S, 5; E=Se, 6) and the polyferrocenyl chalcogenoesters [1,4‐{FcC(O)ECH2}2(C6Me4)] (E=S, 7; E=Se, 8), [1,3,5‐{FcC(O)ECH2}3(C6Me3)] (E=S, 9; E=Se, 10) and [1,2,4,5‐{FcC(O)ECH2}4(C6H2)] (E=S, 11 illustrated; E=Se, 12) are reported. The new polysilylated reagents and polyferrocenyl chalcogenoesters have been characterized by multinuclear NMR spectroscopy (1H, 13C, 77Se), electrospray ionization mass spectrometry and, for complexes 1, 2, 3, 4, 7, 8, and 11, single‐crystal X‐ray diffraction. The cyclic voltammograms of complexes 7–11 are presented.
An Investigation of Photo‐ and Pressure‐Induced Effects in a Pair of Isostructural Two‐Dimensional Spin‐Crossover Framework Materials
Authors: Sciortino Natasha F. , Neville Suzanne M. , Desplanches Cédric , Létard Jean‐François , Martinez Victor , Real José Antonio , Moubaraki Boujemaa , Murray Keith S. , Kepert Cameron J. 
Published: May 2014

AbstractTwo new isostructural iron(II) spin‐crossover (SCO) framework (SCOF) materials of the type [Fe(dpms)2(NCX)2] (dpms=4,4′‐dipyridylmethyl sulfide; X=S (SCOF‐6(S)), X=Se (SCOF‐6(Se))) have been synthesized. The 2D framework materials consist of undulating and interpenetrated rhomboid (4,4) nets. SCOF‐6(S) displays an incomplete SCO transition with only approximately 30 % conversion of high‐spin (HS) to low‐spin iron(II) sites over the temperature range 300–4 K (T1/2=75 K). In contrast, the NCSe− analogue, SCOF‐6(Se), displays a complete SCO transition (T1/2=135 K). Photomagnetic characterizations reveal quantitative light‐ induced excited spin‐state trapping (LIESST) of metastable HS iron(II) sites at 10 K. The temperature at which the photoinduced stored information is erased is 58 and 50 K for SCOF‐6(S) and SCOF‐6(Se), respectively. Variable‐pressure magnetic measurements were performed on SCOF‐6(S), revealing that with increasing pressure both the T1/2 value and the extent of spin conversion are increased; with pressures exceeding 5.2 kbar a complete thermal transition is achieved. This study confirms that kinetic trapping effects are responsible for hindering a complete thermally induced spin transition in SCOF‐6(S) at ambient pressure due to an interplay between close T1/2 and T(LIESST) values.
Facile Preparation of Core–Shell Magnetic Metal–Organic Framework Nanospheres for the Selective Enrichment of Endogenous Peptides
Authors: Xiong Zhichao , Ji Yongsheng , Fang Chunli , Zhang Quanqing , Zhang Lingyi , Ye Mingliang , Zhang Weibing , Zou Hanfa 
Published: May 2014

AbstractFacile preparation of core–shell magnetic metal–organic framework nanospheres by a layer‐by‐layer approach is presented. The nanospheres have high surface area (285.89 cm2 g−1), large pore volume (0.18 cm3 g−1), two kinds of mesopores (2.50 and 4.72 nm), excellent magnetic responsivity (55.65 emu g−1), structural stability, and good dispersibility. The combination of porosity, hydrophobicity, and uniform magnetism was exploited for effective enrichment of peptides with simultaneous exclusion of high molecular weight proteins. The nanospheres were successfully applied in the selective enrichment of endogenous peptides in human serum.
A SIM‐MOF: Three‐Dimensional Organisation of Single‐Ion Magnets with Anion‐Exchange Capabilities
Authors: Baldoví José J. , Coronado Eugenio , Gaita‐Ariño Alejandro , Gamer Christoph , Giménez‐Marqués Mónica , Mínguez Espallargas Guillermo 
Published: May 2014

AbstractThe formation of a metal–organic framework (MOF) with nodes that have single‐molecule magnet (SMM) behaviour has been achieved by using mononuclear lanthanoid analogues, also known as single‐ion magnets (SIMs), which enormously simplifies the challenging issue of making SMM‐MOFs. Here we present a rational design of a family of MOFs, [Ln(bipyNO)4](TfO)3⋅x solvent (Ln=Tb (1); Dy (2); Ho (3); Er (4); TfO=triflate), in which the lanthanoid centres have an square‐antiprismatic coordination environment suitable for SIM behaviour. Magnetic measurements confirm the existence of slow magnetic relaxation typical of SMMs, which has been rationalised by means of a radial effective charge model. In addition, we have explored the incorporation of bulky polyoxometalates (POMs) into the cavities of the SIM‐MOF by anion exchange, finding that they do not interfere with the slow magnetic relaxation. This demonstrates the robustness of the frameworks and opens the possibility of incorporating non‐innocent anions.
Facile Synthesis of Dibenzopentalene Dianions and Their Application as New π‐Extended Ligands
Authors: Kuwabara Takuya , Ishimura Kazuya , Sasamori Takahiro , Tokitoh Norihiro , Saito Masaichi 
Published: May 2014

AbstractReduction of phenyl(silyl)ethynes with potassium followed by quenching with iodine gave dibenzopentalenes in moderate yields. The intermediates of the reactions, dipotassium dibenzopentalenides, were isolated. The first dibenzopentalene–transition‐metal complex was successfully synthesized. The ruthenium atoms are located above the six‐membered rings. However, X‐ray diffraction analysis and theoretical calculations revealed that the aromatic nature of the five‐membered rings was retained. The cyclic voltammetry of the Ru complex revealed two oxidation waves with relatively large separation.
Counterions Control Whether Self‐Assembly Leads to Formation of Stable and Well‐Defined Unilamellar Nanotubes or Nanoribbons and Nanorods
Authors: Shi Dong , Schwall Christian , Sfintes George , Thyrhaug Erling , Hammershøj Peter , Cárdenas Marite , Simonsen Jens B. , Laursen Bo W. 
Published: May 2014

AbstractSelf‐assembly of the amphiphilic π‐conjugated carbenium ion ATOTA‐1+ in aqueous solution selectively leads to discrete and highly stable nanotubes or nanoribbons and nanorods, depending on the nature of the counterion (Cl− vs. PF6−, respectively). The nanotubes formed by the Cl− salt illustrate an exceptional example of a structural well‐defined (29±2 nm in outer diameter) unilamellar tubular morphology featuring π‐conjugated functionality and high stability and flexibility, in aqueous solution.