bluuebunny/crossref_metadata_2025_split huggingface dataset:
Short‐Circuiting Azobenzene Photoisomerization with Electron‐Donating Substituents and Reactivating the Photochemistry with Chemical Modification
Authors: Bandara H. M. Dhammika , Cawley Shannon , Gascón José A. , Burdette Shawn C. 
Published: April 2011

AbstractAzobenzene (AB) undergoes (E) → (Z) isomerization upon exposure to light. Whereas the light‐induced structural change can be exploited for numerous applications, a second, light‐orthogonal switch would facilitate the development of new uses for AB derivatives. Electron‐donating groups on the AB ring system change not only the absorption wavelengths, but also the isomerization properties. Experimental observations and computational studies suggest that the inclusion of multiple electron‐donating groups can short‐circuit the concerted inversion isomerization mechanism of AB by providing new conical intersections between excited states. This phenomenon has been exploited in a unique AB derivative where the conversion of a phenol into an ester restores the isomerization activity.
Chiral micellar electrokinetic chromatography‐atmospheric pressure photoionization of benzoin derivatives using mixed molecular micelles
Authors: He Jun , Shamsi Shahab A. 
Published: April 2011

AbstractIn the present work we report, for the first time, the successful on‐line coupling of chiral MEKC (CMEKC) to atmospheric pressure photoionization MS (APPI‐MS). Four structurally similar neutral test solutes (e.g. benzoin (BNZ) derivatives) were successfully ionized by APPI‐MS. The mass spectra in the positive ion mode showed that the protonated molecular ions of BNZs are not the most abundant fragment ions. Simultaneous enantioseparation by CMEKC and on‐line APPI‐MS detection of four photoinitiators, hydrobenzoin, BNZ, benzoin methyl ether, benzoin ethyl ether, were achieved using an optimized molar ratio of mixed molecular micelle of two polymeric chiral surfactants (polysodium N‐undecenoxy carbonyl‐L‐leucinate and polysodium N‐undecenoyl‐L,L‐leucylvalinate). The CMEKC conditions, such as voltage, chiral polymeric surfactant concentration, buffer pH, and BGE concentration, were optimized using a multivariate central composite design (CCD). The sheath liquid composition (involving %v/v methanol, dopant concentration, electrolyte additive concentration, and flow rate) and spray chamber parameters (drying gas flow rate, drying gas temperature, and vaporizer temperature) were also optimized with CCD. Models built based on the CCD results and response surface method were used to analyze the interactions between factors and their effects on the responses. The final overall optimum conditions for CMEKC‐APPI‐MS were also predicted and found in agreement with the experimentally optimized parameters.
Fiber‐free coupling between bulk laser beams and on‐chip polymer‐based multimode waveguides
Authors: Jensen Thomas G. , Nielsen Lars B. , Kutter Jörg P. 
Published: April 2011

AbstractIn this paper, we demonstrate the design of a virtually alignment‐free optical setup for use with microfluidic applications involving a layered glass/SU‐8/PDMS (polydimethylsiloxane) chip. We show how inexpensive external lenses combined with carefully designed on‐chip lenses can be used to couple light from a bulk beam to on‐chip waveguides and back into a bulk beam again. Using this setup, as much as 20% of the light coming from the source can be retrieved after passing through the on‐chip waveguides. The proposed setup is based on a pin‐aided alignment system that makes it possible to change chips in the optical train in only a few seconds with a standard deviation of about 2% in the transmitted power. Furthermore, we demonstrate how these optical setups can be combined with microfluidics to create an on‐chip flow cytometer enabling detection and counting of polystyrene particles down to 1 μm at a rate of 100 Hz.
A high‐throughput microchip‐based glycan screening assay for antibody cell culture samples
Authors: Primack Jeremy , Flynn Gregory C. , Pan Hai 
Published: April 2011

AbstractA high‐throughput screening assay was developed to quantify major glycan species in the crude mammalian cell culture samples for monoclonal antibodies (mAbs). This method utilizes high‐speed microchip electrophoresis separation following a fast sample preparation procedure. Using a 96‐well ultra‐filtration membrane, interfering species in the cell culture media were efficiently removed as the samples were concentrated. A commercial microchip electrophoresis instrument was used for high‐speed separation, allowing each sample to be analyzed in less than 1 min. This method is well suited for the purpose of high‐throughput antibody glycan profiling during cell culture expression, including clone selection and cell culture process optimization. The relative levels of high mannose (HM), fucosylated and galactosylated glycan species in the Fc domain can be determined for hundreds of crude cell culture samples in a few hours.
Interdigitated comb‐like electrodes for continuous separation of malignant cells from blood using dielectrophoresis
Authors: Alazzam Anas , Stiharu Ion , Bhat Rama , Meguerditchian Ari‐Nareg 
Published: April 2011

AbstractIn this paper, a method for continuous flow separation of circulating malignant cells from blood in a microfluidic device using dielectrophoresis is discussed. Separation of MDA231 breast cancer cells after mixing with normal blood cells was achieved with a level of accuracy that enabled precise counting of the malignant cells, separation and eventually, sub‐culturing. MDA231 cells were separated from the blood to a daughter channel using two pairs of interdigitated activated comb‐like electrode structures. All experiments are performed with conductivity adjusted medium samples. The electrode pairs were positioned divergent and convergent with respect to the flow. The AC signals used in the separation are 20 V peak‐to‐peak with frequencies of 10–50 kHz. The separation is based on balance of magnitude of the dielectrophoretic force and hydrodynamic force. The difference in response between circulating malignant cells and normal cells at a certain band of alternating current frequencies was used for rapid separation of cancer cells from blood. The significance of these experimental results is discussed in this paper, with detailed reporting on the suspension medium, preparation of cells, flow condition and the fabrication process of the microfluidic chip. The present technique could potentially be applied to identify incident cancer at a stage and size that is not yet detectable by standard diagnostic techniques (imaging and biochemical testing). Alternatively, it may also be used to detect cancer recurrences.
Selection of scFv phages specific for chloramphenicol acetyl transferase (CAT), as alternatives for antibodies in CAT detection assays
Authors: Van Dorst Bieke , Mehta Jaytry , Rouah‐Martin Elsa , Backeljau Jelke , De Coen Wim , Eeckhout Dominique , De Jaeger Geert , Blust Ronny , Robbens Johan 
Published: April 2011

ABSTRACTReporter gene assays are commonly used in applied toxicology to measure the transcription of genes involved in toxic responses. In these reporter gene assays, transgenic cells are used, which contain a promoter–operator region of a gene of interest fused to a reporter gene. The transcription of the gene of interest can be measured by the detection of the reporter protein. Chloramphenicol acetyl transferase (CAT) is frequently used as a reporter protein in mammalian reporter gene assays. Although CAT can be measured by different detection systems, like enzymatic and immune assays, most of these tests are expensive, time‐consuming and labor‐intensive. The excellent characteristics of phages, like their high affinity and specificity, their fast, cheap and animal‐friendly manufacturing process with low batch‐to‐batch variations and their stability, make them appropriate as alternatives for antibodies in detection assays. Therefore, in this study single‐chain variable fragment (scFv) phages were selected with affinity for CAT. Several scFv phages were selected that showed affinity towards CAT in a screening ELISA. Surface plasmon resonance analyses showed that the tested scFv phages have an affinity for CAT with a dissociation constant (Kd) around 1 µM. The selected scFv phages in this study could be used as capture elements in a highly sensitive sandwich ELISA to detect CAT concentration as low as 0.1 ng ml−1 or 4 pM. This low detection limit demonstrates the potential of the scFv phages as an alternative for capturing antibodies in a highly sensitive detection test to measure CAT concentrations in reporter gene assays. Copyright © 2011 John Wiley & Sons, Ltd.
Quantitative analysis of shape and volume changes in activated thrombocytes in real time by single‐shot spatial light modulator‐based differential interference contrast imaging
Authors: Khan Saranjam , Jesacher Alexander , Nussbaumer Walter , Bernet Stefan , Ritsch‐Marte Monika 
Published: April 2011

AbstractWe suggest to use a combination of optical tweezers and single‐image quantitative differential interference contrast (DIC) emulated by a spatial light modulator (SLM) to study physiological shape changes in thrombocytes after activation and demonstrate the effectiveness of this system for the given task. A specially designed phase mask displayed at the SLM enables quantitative phase calculation from only a single recording. The optical tweezers stabilize trapped thrombocytes for long‐time monitoring of changes in the optical thickness profile of thrombocytes during activation by adenosine diphosphate (ADP). (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Sea cucumber (Stichopus hermanii) based hydrogel to treat burn wounds in rats
Authors: Zohdi Rozaini Mohd , Zakaria Zuki Abu Bakar , Yusof Norimah , Mustapha Noordin Mohamed , Abdullah Muhammad Nazrul Hakim 
Published: April 2011

AbstractMalaysian sea cucumber was incorporated into hydrogel formulation by using electron beam irradiation technique and was introduced as novel cross‐linked Gamat Hydrogel dressing. This study investigated whether Gamat Hydrogel enhanced repair of deep partial skin thickness burn wound in rats and its possible mechanism. Wounds were treated with either Gamat Hydrogel, control hydrogel, OpSite® film dressing or left untreated. Skin samples were taken at 7, 14, 21, and 28 days post burn for histological and molecular evaluations. Gamat Hydrogel markedly enhanced wound contraction and improved histological reorganization of the regenerating tissue. Furthermore, the dressing modulated the inflammatory responses, stimulated the activation and proliferation of fibroblasts, and enhanced rapid production of collagen fiber network with a consequently shorter healing time. The level of proinflammatory cytokines; IL‐1α, IL‐1β, and IL‐6, were significantly reduced in Gamat Hydrogel treated wounds compared with other groups as assessed by reverse transcription‐polymerase chain reaction (RT‐PCR). In summary, our results showed that Gamat Hydrogel promoted burn wound repair via a complex mechanism involving stimulation of tissue regeneration and regulation of pro‐inflammatory cytokines. The resultant wound healing effects were attributed to the synergistic effect of the hydrogel matrix and incorporated sea cucumber. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.
High‐efficiency cell seeding method by relatively hydrophobic culture strategy
Authors: Hsieh Chin‐Hsiung , Kuo Wei‐Ti , Huang Yi‐Cheng , Huang Yi‐You 
Published: April 2011

AbstractCell adhesion efficiency is one of the key factors affecting the results of manufacturing tissue engineering constructs. High efficiency is required for seeding low proliferation cells onto scaffolds. In this study, we designed a strategy to improve the efficiency of cell adhesion using hydrophobic cell culture environment to enhance cells adhering to a scaffold. Cells have lower affinity to the surface of polydimethylsiloxane (PDMS) than tissue culture polystyrene (TCPS) plates. When cells were cultured with gelatin microspheres or chitosan films in a PDMS‐coated plate instead of a normal TCPS plate, there was a significant increase in cell attachment efficiency. Cells cultured in the PDMS‐coated system tended to selectively attach onto the gelatin microspheres or chitosan films, which are relatively more hydrophilic than the PDMS surface. However, minimal cell attachment on gelatin microspheres or chitosan films was observed when gelatin microspheres or chitosan films were placed in normal TCPS plate. Cell counting experiments with gelatin microspheres in the PDMS‐coated system resulted in a cell attachment efficiency of 89.8% after 1 day of cultivation, whereas the cell attachment efficiency was less than 1% in normal TCPS plate. The results demonstrate that the method is easy to use and could be useful for fast cultivation of cell‐scaffold constructs. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.
Characterizing accelerated capture of deoligomerized TNF within hemoadsorption beads used to treat sepsis
Authors: Kimmel Jeremy D. , Lacko Christopher S. , Delude Russell L. , Federspiel William J. 
Published: April 2011

AbstractSepsis is a systemic inflammatory response to infection, characterized by overexpression of cytokines in the circulating blood. Removal of cytokines and other inflammatory mediators from the blood may help attenuate systemic inflammation during sepsis and improve patient outcomes. In this work, we examined the dynamics of TNF capture within porous, polymeric sorbent beads used in a cytokine adsorption device. We sought to quantify how perturbation of TNF oligomeric structure accelerates TNF removal within the device. TNF was incubated with 10% DMSO for 24 h, which promoted complete monomerization of trimeric TNF, and accelerated TNF capture within the sorbent device compared with native TNF; removal halftime = 13.3 ± 1.5 minversus112.8 ± 13.3 min, respectively. Intramolecular crosslinking stabilized the trimeric TNF structure and prevented DMSO monomerization. Results demonstrate that TNF is an unstable oligomeric molecule that can be dissociated into its smaller monomeric constituents to facilitate faster capture by hemoadsorption beads. Strategies to promote localized TNF deoligomerization at the sorbent surface may significantly accelerate TNF capture rates from the circulating blood using hemoadsorption as a treatment for sepsis. This concept could be extended to improve removal of other oligomeric molecules using size exclusion filtration materials for a variety of disease states. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.
Direct‐write bioprinting three‐dimensional biohybrid systems for future regenerative therapies
Authors: Chang Carlos C. , Boland Eugene D. , Williams Stuart K. , Hoying James B. 
Published: April 2011

AbstractRegenerative medicine seeks to repair or replace dysfunctional tissues with engineered biological or biohybrid systems. Current clinical regenerative models utilize simple uniform tissue constructs formed with cells cultured onto biocompatible scaffolds. Future regenerative therapies will require the fabrication of complex three‐dimensional constructs containing multiple cell types and extracellular matrices. We believe bioprinting technologies will provide a key role in the design and construction of future engineered tissues for cell‐based and regenerative therapies. This review describes the current state‐of‐the‐art bioprinting technologies, focusing on direct‐write bioprinting. We describe a number of process and device considerations for successful bioprinting of composite biohybrid constructs. In addition, we have provided baseline direct‐write printing parameters for a hydrogel system (Pluronic F127) often used in cardiovascular applications. Direct‐write dispensed lines (gels with viscosities ranging from 30 mPa s to greater than 600 × 106 mPa s) were measured following mechanical and pneumatic printing via three commercially available needle sizes (20 ga, 25 ga, and 30 ga). Example patterns containing microvascular cells and isolated microvessel fragments were also bioprinted into composite 3D structures. Cells and vessel fragments remained viable and maintained in vitro behavior after incorporation into biohybrid structures. Direct‐write bioprinting of biologicals provides a unique method to design and fabricate complex, multicomponent 3D structures for experimental use. We hope our design insights and baseline parameter descriptions of direct‐write bioprinting will provide a useful foundation for colleagues to incorporate this 3D fabrication method into future regenerative therapies. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.
The effect of ball milling grinding pathways on the bulk and reactivity properties of calcium phosphate cements
Authors: Lopez‐Heredia M. A. , Bohner M. , Zhou W. , Winnubst A. J. A. , Wolke J. G. C. , Jansen J. A. 
Published: April 2011

AbstractCalcium phosphate cements (CPCs) are significant alternatives to autologous bone grafting. CPCs can be composed of biphasic or multiphase calcium phosphate (CaP) compounds. A common way to process CPCs is by ball milling. Ball milling can be used for grinding or mechanosynthesis. The aim of this study was to determine the effect of well‐defined ball milling grinding parameters, applied via different milling pathways, on the properties of CPCs. Starting CaP compounds used included α‐tricalcium phosphate, dicalcium phosphate anhydrous and precipitated hydroxyapatite. Scanning electron microscopy showed changes in the powder morphology, which were related to the behavior of the starting CaP materials. Specific surface area (SSA) and particle size (PS) measurements exposed the effect of ball milling on the CaP compounds and CPC powders. X‐ray diffraction revealed no effect of ball milling pathways or milling time on the composition of CPCs or the starting materials, but affected their crystallographic properties. No contamination of the milling media or transformation into an amorphous calcium phosphate compound was found. The milling pathways affected setting and cohesion. Fourier transform infrared spectroscopy (FTIR) revealed differences on the CPC v4‐PO43‐ bands according to the interaction, created between the CaP compounds by the milling pathways. FTIR confirmed that the milling pathways changed the crystallographic properties. This study demonstrates that the pathways used for milling grinding modify the PS, SSA, and crystallographic properties of the powders, without affecting their composition. These modifications affected the bulk and reactivity properties of the CPCs by creating different setting and cohesion behaviors. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.
Enhanced bonding between YSZ surfaces using a gas‐phase fluorination pretreatment
Authors: Piascik Jeffrey R. , Wolter Scott D. , Stoner Brian R. 
Published: April 2011

AbstractThe present investigation focuses on the surface modification, via gas‐phase fluorination process, of yttria‐ stabilized zirconia (YSZ) to increase its wettability and chemical bonding directly to acrylate‐based resin cements. YSZ plates and cylinders, as‐received and roughened, were pretreated in a fluorine containing plasma and bonded with a commercially available resin cement for simple shear bond adhesion testing. No organo‐silane coupling agent was used to enhance bonding between the two substrates. Shear bond tests revealed that bond strength increased with fluorination time. Furthermore, the pretreated, as received (nonroughened) specimen group displayed relatively high bond strengths suggesting surface reactivity and direct chemical bonding with the resin cement. X‐ray photoelectron spectroscopy analysis revealed the surface conversion layer to be a mixture of phases; zirconium oxyfluoride, zirconium fluoride, and yttrium fluoride. It is hypothesized that these fluoride and oxyfluoride phases have the potential to increase surface hydroxylation, enabling direct covalent bonding between YSZ and resin cement. It is believed that this surface treatment has broad reaching impact when using high‐strength ceramics in a multitude of bioapplications. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.
Ubiquitination and downregulation of ErbB2 and estrogen receptor‐alpha by kinase inhibitor MP‐412 in human breast cancer cells
Authors: Suzuki Tsuyoshi , Fujii Akihiro , Ochi Hiroshi , Nakamura Hideo 
Published: April 2011

AbstractErbB2 has been proven to be an important target for breast cancer therapy. MP‐412 is a dual ErbB2 and epidermal growth factor receptor tyrosine kinase inhibitor belonging to an irreversible‐type anilinoquinazoline derivative. We demonstrate herein that along with the kinase inhibition, MP‐412 has the ability to induce ubiquitination, internalization, and degradation of ErbB2 in several human breast cancer cell lines at concentrations relatively higher than those required for kinase inhibition. Another irreversible inhibitor, CI‐1033, showed similar activity, while the reversible compounds were ineffective, suggesting a crucial role of covalent bonding functionality in these effects. In MCF7 cells, MP‐412 depleted not only ErbB2 but also estrogen receptor (ER)‐α, and to some extent, affected Raf‐1, while MP‐412 activated Hsp70 expression. Moreover, we observed that MP‐412 increased immunocomplexing of Hsp70 with ErbB2 and ER‐α, with simultaneous induction of ubiquitination of these client proteins. Furthermore, in combination with proteasome inhibitor, MP‐412 resulted in the noticeable accumulation of ErbB2 and ER‐α in the detergent insoluble fraction of cell lysates. These results suggest that MP‐412 acts as an inhibitor of Hsp90 function, whereas MP‐412 did not bind directly to ATP‐binding site of Hsp90, unlike geldanamycin. We also found that new protein synthesis was involved in the activity of MP‐412 on Hsp90 modulation. Since downregulation of ErbB2 and ER‐α by accelerating the ubiquitin‐proteolysis system will become an attractive approach for breast cancer therapy, we expect MP‐412 to be a lead compound for the drug design and the development of such agents. J. Cell. Biochem. 112: 2279–2286, 2011. © 2011 Wiley‐Liss, Inc.