bluuebunny/crossref_metadata_2025_split huggingface dataset:
Asymmetric Synthesis of Functionalized Bicyclic β‐Amino Alcohols by Cascade Hydrometallation–Cyclization–Reduction of Glycinyl‐Substituted Alkenylsulfox­imines – Application to the Synthesis of an Aggrecanase Inhibitor Mimic
Authors: Acikalin Serdar , Raabe Gerhard , Runsink Jan , Gais Hans‐Joachim 
Published: August 2011

AbstractThe treatment of exocyclic alkenylsulfoximines, which carry an α‐glycinyl group at the allylic position, with HAliBu2 caused cascade hydroalumination–cyclization–reduction and delivered the corresponding enantio‐ and diastereopure sulfoximine‐substituted bicyclic β‐amino alcohols with a bicyclo[3.3.0]octane and bicyclo[4.3.0]nonane skeleton in high yields. Three consecutive stereogenic C atoms of the bicyclic β‐amino alcohols were generated in the cascade reactions with high diastereoselectivities. Application of the hydroalumination–cyclization–reduction to a ketal‐substituted six‐membered exocyclic alkenylsulfoximine afforded the corresponding sulfoximine‐substituted β‐amino alcohol with aketal‐functionalized bicyclo[4.3.0]nonane skeleton. Reduction of a sulfoximine‐substituted β‐amino alcohol gave the parent β‐amino alcohol, whereas its oxidative deamination afforded the corresponding sulfonyl‐substituted β‐amino alcohol. The treatment of a sulfoximine‐substituted β‐amino alcohol with chloro‐ and iodoformates stereoselectively furnished the corresponding chloro‐ and iodo‐substituted β‐amino alcohols. Finally, the feasibility of a dehydration and elimination of sulfoximine‐substituted β‐amino alcohols with formation of the corresponding amino‐substituted alkenylsulfoximine and allylic amine was demonstrated. An enantio‐ and diastereopure protected aggrecanase inhibitor mimic was synthesized in high yield starting from the sulfoximine‐substituted bicyclic β‐amino alcohol with a bicyclo[4.3.0]nonane skeleton and (R)‐2‐(3‐benzyloxy)benzyl‐4‐tert‐butoxy‐4‐oxobutanoic acid. Coupling of both building blocks gave the corresponding succinamide, the tert‐butoxycarbonyl group of which was converted into the corresponding O‐benzyl‐hydroxycarbamoyl group.
Insulator‐based dielectrophoretic single particle and single cancer cell trapping
Authors: Bhattacharya Sanchari , Chao Tzu‐Chiao , Ros Alexandra 
Published: August 2011

AbstractTrapping of individual cells at specific locations in a microfluidic lab‐on‐a‐chip platform is essential for single cell studies, especially those requiring individual stimulation followed by downstream analysis. To this aim, we have designed microdevices based on direct current (DC) insulator‐based dielectrophoresis (iDEP) acting as individual single cell traps. We present both the design of a negative iDEP trap and a positive iDEP trap using insulating posts integrated at microchannel intersections. We obtained electric field distributions via numerical simulations adapted to the intersection and trap geometry with which we predict single particle pathlines. With polystyrene particles of 10 μm diameter, we demonstrated an effective design for a single particle trap in the case of negative dielectrophoresis. The onset trapping voltage shows an inverse relation to the buffer conductivity, thus indicating the influence of electrokinetic effects on the trapping behavior. Additionally, we demonstrated the proof‐of‐principle of single MCF‐7 breast cancer cell trapping in a positive iDEP trap. Our single particle trapping experiments were further in very good agreement with numerical simulations. To ensure that no significant damage occurred to the cells during the experiment, we further optimized medium conditions to ensure viability of the cells for at least 1 h, more than sufficient for microfluidic trapping experiments. Our results thus indicated the successful design of DC iDEP traps, which can easily be integrated into a variety of microchip operations for single cell analysis.
Explorations of ABO‐Rh antigen expressions on erythrocyte dielectrophoresis: Changes in cross‐over frequency
Authors: Leonard Kaela M. , Minerick Adrienne R. 
Published: August 2011

AbstractA quadrupole dielectrophoretic microdevice was utilized to examine the ABO‐Rh dependencies on erythrocyte polarizations. This important step toward medical microdevice technology would transform key clinical blood tests from the laboratory into the field. Previous work in dielectrophoretic microdevices demonstrated that the large number of ABO antigens on erythrocyte membranes impacts their dielectrophoretic signature at 1 MHz. This work explores the dielectrophoretic behavior of native human erythrocytes categorized by their ABO‐Rh blood types and directly compares these responses to the same erythrocyte sample modified to remove the A and B antigens. A β(1–3)‐galactosidase enzyme was utilized to cleave the ABO polysaccharide backbone at the galactosidase bonds. The enzymatic reaction was optimized by comparing agglutination of the native and modified blood cells in addition to UV–Vis and HPLC analysis of the reaction effluent for saccharide residues. Next, the dielectrophoretic behaviors of the native and modified erythrocytes were visually verified in a quadrupole electrode microdevice over a frequency range from 100 kHz to 80 MHz. The lower cross‐over frequency (COF), which transitions from negative to positive dielectrophoresis, for ABO blood types tested (A+, A−, B+, B−, AB+, O+ and O−) differed over the range from 17 to 47 MHz. The COFs of the corresponding enzyme‐modified erythrocytes were also determined and the range narrowed to 29–41 MHz. A second COF in the 70–80 MHz range was observed and was reduced in the presence of the transmembrane Rhesus factor. These results suggest that antigen expression on erythrocyte membrane surfaces influence cell polarizations in nonuniform AC fields.
Separation of mixtures of particles in a multipart microdevice employing insulator‐based dielectrophoresis
Authors: Gallo‐Villanueva Roberto C. , Pérez‐González Victor H. , Davalos Rafael V. , Lapizco‐Encinas Blanca H. 
Published: August 2011

AbstractDielectrophoresis is the electrokinetic movement of particles due to polarization effects in the presence of non‐uniform electric fields. In insulator‐based dielectrophoresis (iDEP) regions of low and high electric field intensity, i.e. non‐uniformity of electric field, are produced when the cross‐sectional area of a microchannel is decreased by the presence of electrical insulating structures between two electrodes. This technique is increasingly being studied for the manipulation of a wide variety of particles, and novel designs are continuously developed. Despite significant advances in the area, complex mixture separation and sample fractionation continue to be the most important challenges. In this work, a microchannel design is presented for carrying out direct current (DC)‐iDEP for the separation of a mixture of particles. The device comprises a main channel, two side channels and two sections of cylindrical posts with different diameters, which will generate different non‐uniformities in the electric field on the main channel, designed for the discrimination and separation of particles of two different sizes. By applying an electric potential of 1000 V, a mixture of 1 and 4 μm polystyrene microspheres were dielectrophoretically separated and concentrated at the same time and then redirected to different outlets. The results obtained here demonstrate that, by carefully designing the device geometry and selecting operating conditions, effective sorting of particle mixtures can be achieved in this type of multi‐section DC‐iDEP devices.
Characterization of lead induced metal–phytochelatin complexes in Chlamydomonas reinhardtii
Authors: Scheidegger Christian , Sigg Laura , Behra Renata 
Published: August 2011

Abstract
Accumulation of Pb and induction of phytochelatin synthesis were observed in Chlamydomonas reinhardtii upon Pb(II) exposure. Our aim was to examine whether Pb(II) is bound by phytochelatins (PCs) in C. reinhardtii and to examine formed complexes for their stoichiometry and composition. Metal–phytochelatin (Me-PC) complexes induced by Pb were isolated by size-exclusion chromatography in 13 collected fractions, which were analyzed for their PC and metal content by high-performance liquid chromatography and inductively coupled plasma mass spectrometry. A recovery of more than 90% of Pb from standard Pb-PC2 complexes within the total volume of the size-exclusion column indicated the adequacy of the method for Pb-PCn complex separation and characterization. Phytochelatins were detected mainly in a molecular weight ranging from 1,000 to 5,300 daltons (Da), indicating the formation of complexes with various stoichiometries. Approximately 72% of total PC2 eluted in the range from 1,000 to 1,600 Da, and 80% of total PC3 eluted in the molecular weight range from 1,600 to 2,300 Da. The distribution of Cu, Zn, and Pb showed that more than 70% of these metals were associated with the high-molecular-weight fractions. Copper, zinc, and lead were also observed in PC-containing fractions, suggesting the formation of various Me-PC complexes. The results of the present study indicate that the role of PCs in Pb detoxification is minor, because only 13% of total Pb was associated with PCs. Environ. Toxicol. Chem. 2011;30:2546–2552. © 2011 SETAC
Epidermal growth factor receptor expression in acute myelogenous leukaemia is associated with clinical prognosis
Authors: Sun Jun‐Zhong , Lu Ying , Xu Yin , Liu Fang , Li Fu‐Quan , Wang Quan‐Li , Wu Chu‐Tse , Hu Xian‐Wen , Duan Hai‐Feng 
Published: August 2011

AbstractThe epidermal growth factor receptor (EGFR) family belongs to type I receptor tyrosine kinases. Overexpression or mutation of EGFR/ErbB1 gene has been detected in a large number of human solid tumours. According to some previous report, this gene is not expressed in hematological malignancies. However, two recent clinical case reports showed that erlotinib caused complete remission of acute myeloid leukaemia (AML)‐M1 in patients who had both AML‐M1 and non‐small‐cell lung cancer. These results are supported by preclinical studies in which EGFR tyrosine kinase inhibitors have anti‐proliferative effects on AML. These findings prompted us to determine whether EGFR is expressed in human AML, through a large‐scale screening of both leukaemic cell lines and clinical samples. Our results show that EGFR is expressed by about 33% of human AML (containing M1 to M7 subtypes) and by some human leukaemia cell lines (K562, MEG‐01, CEM and SKO‐007). Its expression is not limited to certain AML types but has been detected in many leukaemic cells. In addition, EGFR expression was intimately associated with the poor clinical outcomes. Finally, we find that only EGFR‐positive leukaemic cells respond to antibody‐dependent cellular cytotoxicity of cetuximab, the monoclonal antibodies against EGFR. Copyright © 2011 John Wiley & Sons, Ltd.
Repeated transfusions of autologous cytokine‐induced killer cells for treatment of haematological malignancies in elderly patients: a pilot clinical trial
Authors: Yang Bo , Lu Xue‐chun , Yu Rui‐li , Chi Xiao‐hua , Liu Yang , Wang Yao , Dai Han‐ren , Zhu Hong‐li , Cai Li‐li , Han Wei‐dong 
Published: August 2011

AbstractThe elderly population is susceptible to haematological malignancies, and these elderly patients are intolerant to cytotoxic drugs. Therefore, the exploration of a safe and reliable strategy exclusive of chemotherapy is critical in improving the prognosis of elderly patients with haematological malignancies. We evaluated the safety and the efficacy of autologous cytokine‐induced killer (CIK) cells combined with recombinant human interleukin 2 (rhIL‐2) in the treatment of haematological malignancies in elderly patients. Peripheral blood mononuclear cells were isolated from 20 elderly patients with haematological malignancies, then augmented by priming with interferon gamma, rhIL‐2 and CD3 monoclonal antibody. The autologous CIK cells (2–3 × 109) were transfused back to patients, followed by a subcutaneous injection of IL‐2 (1 mU/day) for 10 consecutive days. The regimen was repeated every 4 weeks. The host cellular immune function, tumour‐related biological parameters, imaging characteristics, disease condition, quality of life and survival time were assessed. Fourteen patients received 8 cycles of transfusion and 6 received 4 cycles. No adverse effects were observed. The percentages of CD3+, CD3+CD8+ and CD3+CD56+ cells were significantly increased (p < 0.05), and the levels of serum β2 microglobulin and lactate dehydrogenase (LDH) were markedly decreased (p < 0.05) after autologous CIK cell transfusion. Cancer‐related symptoms were profoundly alleviated, as demonstrated by the improved quality of life (p < 0.01). Complete remission was observed in 11 patients, persistent partial remission in 7 patients and stable disease in 2 patients. At the end of follow‐up, the mean survival time was 20 months. Transfusion with autologous CIK cells plus rhIL‐2 treatment is safe and effective for treating haematological malignancies in elderly patients. Copyright © 2011 John Wiley & Sons, Ltd.
Polyimine Container Molecules and Nanocapsules
Authors: Rue Nicholas M. , Sun Junling , Warmuth Ralf 
Published: August 2011

AbstractThe field of dynamic covalent nanocapsule synthesis is very young, and most contributions to the development of reliable approaches for the assembly of dynamic covalent capsules have been made during the past five years. In 1991, Quan and Cram published the first Schiff base molecular container compound. Over the past six years, a large number of multi‐component polyimine hemicarcerand and polyhedron syntheses have been developed. This review will focus primarily on recent achievements in the area of pure Schiff base nanocapsules and highlight different synthetic approaches and design strategies, as well as first applications of these capsules in molecular recognition, gas storage, and gas separation.
Tissue distribution and histopathological effects of titanium dioxide nanoparticles after intravenous or subcutaneous injection in mice
Authors: Umbreit T. H. , Francke‐Carroll S. , Weaver J. L. , Miller T. J. , Goering P. L. , Sadrieh N. , Stratmeyer M. E. 
Published: August 2011

ABSTRACTNanoparticles can be formed following degradation of medical devices such as orthopedic implants. To evaluate the safety of titanium alloy orthopedic materials, data are needed on the long‐term distribution and tissue effects of injected titanium nanoparticles in experimental animals. In this study, we evaluated the tissue distribution and histopathological effects of titanium dioxide (TiO2) nanoparticles (approximately 120 nm diameter) in mice after intravenous (i.v.; 56 or 560 mg kg−1 per mouse) or subcutaneous (s.c.; 560 or 5600 mg kg−1 per mouse) injection on two consecutive days. Animals were examined 1 and 3 days, and 2, 4, 12 and 26 weeks after the final injection. When examined by light microscopy, particle agglomerates identified as TiO2 were observed mainly in the major filtration organs – liver, lung and spleen – following i.v. injection. Particles were still observed 26 weeks after injection, indicating that tissue clearance is limited. In addition, redistribution within the histological micro‐compartments of organs, especially in the spleen, was noted. Following s.c. injection, the largest particle agglomerates were found mainly in the draining inguinal lymph node, and to a lesser extent, the liver, spleen and lung. With the exception of a foreign body response at the site of s.c. injection and the appearance of an increased number of macrophages in the lung and liver, there was no histopathological evidence of tissue damage observed in any tissue at any time point. Published 2011. This article is a US Government work and is in the public domain in the USA.
Polypyrrole‐contained electrospun conductive nanofibrous membranes for cardiac tissue engineering
Authors: Kai Dan , Prabhakaran Molamma P. , Jin Guorui , Ramakrishna Seeram 
Published: August 2011

AbstractCardiac tissue engineering (TE) is one of the most promising strategies to reconstruct infarct myocardium and the major challenge is to generate a bioactive substrate with suitable chemical, biological, and conductive properties, thus mimicking the extracellular matrix (ECM) both structurally and functionally. In this study, polypyrrole/poly(ε‐caprolactone)/gelatin nanofibrous scaffolds were electrospun by incorporating different concentrations of polypyrrole (PPy) to PCL/gelatin (PG) solution. Morphological, chemical, mechanical, and biodegradation properties of the electrospun nanofibers were evaluated. Our data indicated that by increasing the concentration of PPy (0–30%) in the composite, the average fiber diameters reduced from 239 ± 37 nm to 191 ± 45 nm, and the tensile modulus increased from 7.9 ± 1.6 MPa to 50.3 ± 3.3 MPa. Conductive nanofibers containing 15% PPy (PPG15) exhibited the most balanced properties of conductivity, mechanical properties, and biodegradability, matching the requirements for regeneration of cardiac tissue. The cell proliferation assay, SEM, and immunostaining analysis showed that the PPG15 scaffold promote cell attachment, proliferation, interaction, and expression of cardiac‐specific proteins better than PPG30. Electrospun PPG15 conductive nanofibrous scaffold could be desirable and promising substrates suitable for the regeneration of infarct myocardium and cardiac defects. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011.
Ubiquitination-deubiquitination balance dictates ligand-stimulated PTHR sorting
Authors: Alonso Verónica , Magyar Clara E , Wang Bin , Bisello Alessandro , Friedman Peter A 
Published: August 2011

Abstract
Parathyroid hormone receptors (PTHR) are promptly internalized upon stimulation by activating (PTH[1-84], PTH[1-34]) and non-activating (PTH[7-84], PTH[7-34]) ligands. Here, we characterized the mechanism regulating the sorting of internalized receptors between recycling and degradative pathways. PTHR recycles faster after challenge with PTH(1-34) than with PTH(7-34). PTHR recycling is complete by 2 h after PTH(1-34) stimulation, but incomplete at this time in cells treated with PTH(7-34). The slower and incomplete recycling induced by PTH(7-34) is due to proteasomal degradation. Both PTH(1-34) and PTH(7-34) induced PTHR polyubiquitination. Ubiquitination by PTH(1-34) was transient, whereas receptor ubiquitination after PTH(7-34) was sustained. PTH(1-34), but not PTH(7-34), induced expression of the PTHR-specific deubiquitinating enzyme USP2. Overexpression of USP2 prevented PTH(7-34)-induced PTHR degradation. We conclude that PTH(1-34) promotes coupled PTHR ubiquitination and deubiquitination, whereas PTH(7-34) activates only ubiquitination, thereby leading to PTHR downregulation. These findings may explain PTH resistance in diseases associated with elevated PTH(7-84) levels. © 2011 American Society for Bone and Mineral Research
miR‐520c and miR‐373 upregulate MMP9 expression by targeting mTOR and SIRT1, and activate the Ras/Raf/MEK/Erk signaling pathway and NF‐κB factor in human fibrosarcoma cells
Authors: Liu Ping , Wilson Michael J. 
Published: August 2011

AbstractMicroRNA 520c and 373 (miR‐520c and miR‐373) have been characterized as oncogenes and play critical roles in cancer cell metastasis. However, the relationship between these two microRNAs and matrix metalloproteinases (MMPs), which are important in cancer cell metastasis, remains unknown. Here, we report new evidence in which miR‐520c and miR‐373 effects in human fibrosarcoma HT1080 cells are associated with MMP9 activity, and this upregulation of MMP9 is not only at the activity and protein levels, but also at that of its mRNA. Our experimental data demonstrate that these effects occur not by direct binding to the MMP9 promoter, but by miR‐520c and miR‐373 directly targeting the 3′‐untranslational region (UTR) of mRNAs of mTOR and SIRT1 (negative regulators of expression of MMP9 via inactivating the Ras/Raf/MEK/Erk signaling pathway and transcription factor NF‐κB activity); and thus suppressing translation levels of SIRT1 and mTOR. Moreover, inhibition of key kinases of the Ras/Raf/MEK/Erk signaling pathway and Western blots for selected proteins further identified miR‐520c and miR‐373 as activating this signaling pathway and NF‐κB. In conclusion, miR‐520c and miR‐373 increased the expression of MMP9 by directly targeting the 3′‐UTRs of mRNAs of mTOR and SIRT1 and suppressing their translation; resulting in activation of the Ras/Raf/MEK/Erk signaling pathway and NF‐κB; and, finally, increasing the mRNA, protein, and activity of MMP9 and enhancing cell migration and cell growth in 3D type I collagen gels. J. Cell. Physiol. 227: 867–876, 2012. © 2011 Wiley Periodicals, Inc.
Clinical and economic outcomes of low‐field intraoperative MRI‐guided tumor resection neurosurgery
Authors: Makary Mina , Chiocca E. Antonio , Erminy Natali , Antor María , Bergese Sergio D. , Abdel‐Rasoul Mahmoud , Fernandez Soledad , Dzwonczyk Roger 
Published: August 2011

AbstractPurpose:To compare low‐field (0.15 T) intraoperative magnetic resonance imaging (iMRI)‐guided tumor resection with both conventional magnetic resonance imaging (cMRI)‐guided tumor resection and high‐field (1.5 T) iMRI‐guided resection from the clinical and economic point of view.Materials and Methods:We retrospectively compared 65 iMRI patients with 65 cMRI patients in terms of hospital length of stay, repeat resection rate, repeat resection interval, complication rate, cost to the patient, cost to the hospital, and cost effectiveness. In addition, we compared our low‐field results with previously published high‐field results.Results:The complication rate was lower for iMRI vs. cMRI in patients presenting for their initial tumor resection (45 vs. 57 complications, P = 0.048). The iMRI repeat resection interval was longer for this cohort (20.1 vs. 6.7 months, P = 0.020). iMRI was more cost‐effective than cMRI for patients who had repeat resections ($10,690/RFY vs. $76,874/RFY, P < 0.001). We found no other clinical or economic differences between iMRI‐ and cMRI‐guided tumor resection surgeries. Overall, we did not find the advantages to low‐field iMRI that have been reported for high‐field iMRI.Conclusion:There is no adequate justification for the widespread installation of low‐field iMRI in its current development state. J. Magn. Reson. Imaging 2011;. © 2011 Wiley Periodicals, Inc.
Molecularly imprinted solid‐phase extraction coupled with HPLC for the selective determination of monobutyl phthalate in bottled water
Authors: Qi Peipei , Wang Jincheng , Li Yun , Su Fan , Jin Jing , Chen Jiping 
Published: August 2011

AbstractA molecularly imprinted polymer (MIP) was prepared using monobutyl phthalate as template. The synthesis was optimized by using different porogens and functional monomers. The MIP was used as a selective sorbent in molecularly imprinted solid‐phase extraction (MIP‐SPE) for pre‐concentration and determination of monobutyl phthalate (mBP) from the bottled water. The difference in recognition selectivity of the polymer columns was observed in HPLC system, and the effect of the mobile phase on the performance of MIP columns was also investigated. Control of the MIP‐SPE process is seen as important in helping to facilitate the selective extraction of mBP from water samples. Thereafter, the choice of washing solvent, eluting solvent amount, pH of loading sample, flow rate of loading solution and the loading sample volume was presented. The optimized procedure was described as follows: 25 mL spiked aqueous solution was percolated through the MIP‐SPE cartridge at the flow rate of 1.5 mL/min. After rinsing with acetonitrile/methanol mixture (1:1, v/v), the bound analyte was desorbed with 3 mL methanol. The developed MIP‐SPE method was demonstrated to be applicable for the analysis of mBP in the bottled water.