bluuebunny/crossref_metadata_2025_split huggingface dataset:
Recent studies of iron deficiency during brain development in nonhuman primates
Authors: Golub Mari S. 
Published: March 2010

AbstractRecent studies of the effects of developmental iron deficiency (ID) and iron deficiency anemia in nonhuman primates have provided new insights into this widespread and well‐recognized human nutritional deficiency. The rhesus monkey was the animal model in these experiments, which used extensive hematological and behavioral evaluations in addition to noninvasive brain measures. Two important findings were as follows: 1) different behavioral consequences depending on the timing of ID relative to brain developmental stages and 2) the potential for long‐lasting changes in brain iron regulatory systems. Further work in this model, including integration with studies in humans and in laboratory rodents, is ongoing.
Oligodendrogenesis: The role of iron
Authors: Badaracco Maria Elvira , Siri Maria Victoria Rosato , Pasquini Juana Maria 
Published: March 2010

AbstractIron seems to be an essential factor in myelination and oligodendrocyte (OLGc) biology. However, the specific role of iron in these processes remains to be elucidated. Iron deficiency (ID) imposed to developing rats has been a relevant model to understand the role of iron in oligodendrogenesis and myelination. During early development ID causes specific changes in myelin composition, including a lower relative content of cholesterol, proteolipid protein (PLP), and myelin basic protein 21 (MBP21). These changes could be a consequence of the adverse effects of ID on OLGc development and function. We subsenquently studied the possible corrective effect of a single intracranial injection (ICI) of apotransferrin (aTf) on myelin formation in ID rats OLGc migration and differentiation after an ICI of aTf was evaluated at 3 days of age. ID increased the number of proliferating and undifferentiated cells in the corpus callosum (CC), while a single aTf injection reverts these effects, increasing the number of mature cells and myelin formation. Overall, results of a series of studies supports the concept that iron may affect OLGc development at early stages of embryogenesis rather than during late development. Myelin composition is altered by a limited iron supply, changes that can be reverted by a single injection of aTf.
Metabolic responses of Taxus media transformed cell cultures to the addition of methyl jasmonate
Authors: Exposito Oscar , Syklowska‐Baranek Katarzyna , Moyano Elisabeth , Onrubia Miriam , Bonfill Mercedes , Palazon Javier , Cusido Rosa M. 
Published: March 2010

AbstractDedifferentiated Taxus media cell cultures presenting the same genetic characteristics as the parent culture were established from transformed roots. Two transformed cell lines were studied: Rol C, carrying the T‐DNA of A. rhizogenes 9,402 and TXS, carrying both the T‐DNA of A. rhizogenes and the txs transgene of T. baccata under the control of the 35S CaMV promoter. In the second part of a previously optimized two‐stage system, the transformed cell lines were cultured in a production medium supplemented with the elicitor methyl jasmonate. Taxane production in the transformed cultures was compared with an untransformed T. media cell line cultured in the same conditions. The highest taxane production was observed in the TXS cell line when cultured in the optimized production medium with methyl jasmonate, being 265% greater than in the untransformed control and 170% greater than in the Rol C cell line. However, txs expression and the activity of the enzyme taxadiene synthase in the TXS cells were lower than in the line carrying only the rol genes (Rol C). It is also noteworthy that the taxane production as well as the txs gene expression and TXS activity in all the cell lines, both transformed and untransformed, were clearly dependent on the elicitor action. © 2010 American Institute of Chemical Engineers Biotechnol. Prog., 2010
Combining high‐throughput screening of caspase activity with anti‐apoptosis genes for development of robust CHO production cell lines
Authors: Dorai Haimanti , Ellis Dawn , Keung Yun Seung , Campbell Marguerite , Zhuang Minhong , Lin Chengbin , Betenbaugh Michael J. 
Published: March 2010

AbstractA set of anti‐apoptotic genes were over‐expressed, either singly or in combination, in an effort to develop robust Chinese Hamster Ovary host cell lines suitable for manufacturing biotherapeutics. High‐throughput screening of caspase 3/7 activity enabled a rapid selection of transfectants with reduced caspase activity relative to the host cell line. Transfectants with reduced caspase 3/7 activity were then tested for improved integrated viable cell count (IVCC), a function of peak viable cell density and longevity. The maximal level of improvement in IVCC could be achieved by over‐expression of either single anti‐apoptotic genes, e.g., Bcl‐2Δ (a mutated variant of Bcl‐2) or Bcl‐XL, or a combination of two or three anti‐apoptotic genes, e.g., E1B‐19K, Aven, and XIAPΔ. These cell lines yielded higher transient antibody production and a greater number of stable clones with high antibody yields. In a 5 L fed‐batch bioreactor system, BΔ31‐1, a stable clone expressing Bcl‐2Δ, had a product titer that was 180% as compared to an optimal clone (Con‐1) from the control cell line. Although lactate accumulated to more than 5 g/L in the control culture, its concentration was reduced in the anti‐apoptotic BΔ31‐1 cultures to below 1 g/L, confirming our earlier findings that cells over‐expressing anti‐apoptotic genes consume the lactate that would otherwise accumulate as a by‐product in the culture medium. To the best of our knowledge, this is the first study to use the high throughput caspase screening method to identify CHO host cell lines with superior anti‐apoptotic characteristics. © 2010 American Institute of Chemical Engineers Biotechnol. Prog., 2010
His‐tagged protein purification by metal‐chelate affinity extraction with nickel‐chelate reverse micelles
Authors: Dong Xiao‐Yan , Feng Xu‐Dong , Sun Yan 
Published: March 2010

AbstractDi(2‐ethylhexyl) phosphoric acid (HDEHP) was used as a transition metal ion chelator and introduced to the nonionic reverse micellar system composed of equimolar Triton X‐45 and Span 80 at a total concentration of 30 mmol/L. Ni(II) ions were chelated to the HDEHP dimers in the reverse micelles, forming a complex denoted as Ni(II)R2. The Ni(II)‐chelate reverse micelles were characterized for the purification of recombinant hexahistidine‐tagged enhanced green fluorescent protein (EGFP) expressed in Escherichia coli. The affinity binding of EGFP to Ni(II)R2 was proved by investigation of the forward and back extraction behaviors of purified EGFP. Then, EGFP was purified with the affinity reverse micelles. It was found that the impurities in the feedstock impeded EGFP transfer to the reverse micelles, though they were little solubilized in the organic phase. The high specificity of the chelated Ni2+ ions toward the histidine tag led to the production of electrophoretically pure EGFP, which was similar to that purified by immobilized metal affinity chromatography. A two‐stage purification by the metal‐chelate affinity extraction gave rise to 87% recovery of EGFP. Fluorescence spectrum analysis suggests the preservation of native protein structure after the separation process, indicating the system was promising for protein purification. © 2010 American Institute of Chemical Engineers Biotechnol. Prog., 2010
Investigation of beta‐glucans binding to human/mouse dectin‐1 and associated immunomodulatory effects on two monocyte/macrophage cell lines
Authors: Wu Mei‐Li , Huang Tzou‐Chi , Hung Hui‐Ju , Yu Jou‐Hui , Chung Wen‐Bin , Chaung Hso‐Chi 
Published: March 2010

AbstractDectin‐1, a specific pattern recognition receptor for β‐1,3/β‐1,6‐glucans, is expressed mainly on phagocytes. Human dectin‐1 (hDectin‐1) and mouse dectin‐1 (mDectin‐1) were separately expressed on HEK293 cell surfaces for examination of the binding abilities of a synthetic particulate β‐glucan (pβG), a product extracted from Saccharomyces cerevisiae, in this study. The binding of zymosan‐FITC to hDectin‐1 and mDectin‐1 was inhibited by pβG at similar concentrations for 50% inhibition of binding (IC50). However, the kinetics of the time course and dose response to zymosan stimulation observed for U937 and J774A.1 differed. Superoxide anion production was increased in U937 but reduced in J774A.1 when cells were treated with pβG, zymosan, or laminarin, whereas ovalbumin endocytosis was enhanced in U937 and J774A.1 treated either with pβG, zymosan, laminarin, or barley‐glucan. These results indicate that the binding affinity of pβG to hDectin‐1 is similar to the binding affinity to mDectin‐1, and that stimulation by pβG as well as various forms of β‐1,3‐glucans on U937 and J774A.1 resulted in upregulation of cell activity and ovalbumin endocytosis. Additionally, other coreceptors on U937 and J774A.1 may be involved in directing different responses to superoxide anion production in these two types of cells. These results will likely contribute to further investigations on identifying the biological forms of β‐glucans capable of binding its specific receptor as the effective immunomodulators. © 2010 American Institute of Chemical Engineers Biotechnol. Prog., 2010
A device for separated and reversible co‐culture of cardiomyocytes
Authors: Chen Michael Q. , Whittington R. Hollis , Day Peter W. , Kobilka Brian K. , Giovangrandi Laurent , Kovacs Gregory T. A. 
Published: March 2010

AbstractA novel technique is introduced for patterning and controllably merging two cultures of adherent cells on a microelectrode array (MEA) by separation with a removable physical barrier. The device was first demonstrated by separating two cardiomyocyte populations, which upon merging synchronized electrical activity. Next, two applications of this co‐culture device are presented that demonstrate its flexibility as well as outline different metrics to analyze co‐cultures. In a differential assay, the device contained two distinct cell cultures of neonatal wild‐type and β‐adrenergic receptor (β‐AR) knockout cardiomyocytes and simultaneously exposed them with the β‐AR agonist isoproterenol. The beat rate and action potential amplitude from each cell type displayed different characteristic responses in both unmerged and merged states. This technique can be used to study the role of β‐receptor signaling and how the corresponding cellular response can be modulated by neighboring cells. In the second application, action potential propagation between modeled host and graft cell cultures was shown through the analysis of conduction velocity across the MEA. A co‐culture of murine cardiomyocytes (host) and murine skeletal myoblasts (graft) demonstrated functional integration at the boundary, as shown by the progression of synchronous electrical activity propagating from the host into the graft cell populations. However, conduction velocity significantly decreased as the depolarization waves reached the graft region due to a mismatch of inherent cell properties that influence conduction. © 2010 American Institute of Chemical Engineers Biotechnol. Prog., 2010
A simple apparatus for measuring cell settling velocity
Authors: Wang Zhaowei , Belovich Joanne M. 
Published: March 2010

AbstractAccurate cell settling velocity determination is critical for perfusion culture using a gravity settler for cell retention. We have developed a simple apparatus (a “settling column”) for measuring settling velocity and have validated the procedure with 15‐μm polystyrene particles with known physical properties. The measured settling velocity of the polystyrene particles is within 4% of the value obtained using the traditional Stokes' law approach. The settling velocities of three hybridoma cell lines were measured, resulting in up to twofold variation among cell lines, and the values decreased as the cell culture aged. The settling velocities of the nonviable cells were 33–50% less than the corresponding viable cells. The significant variation of settling velocities among cell populations and growth phases confirms the necessity of routine measurement of this property during long‐term perfusion culture. © 2010 American Institute of Chemical Engineers Biotechnol. Prog., 2010
β‐Aminopeptidase‐Catalyzed Biotransformations of β2‐Dipeptides: Kinetic Resolution and Enzymatic Coupling
Authors: Heck Tobias , Reimer Artur , Seebach Dieter , Gardiner James , Deniau Gildas , Lukaszuk Aneta , Kohler Hans‐Peter E. , Geueke Birgit 
Published: March 2010

AbstractWe have previously shown that the β‐aminopeptidases BapA from Sphingosinicella xenopeptidilytica and DmpA from Ochrobactrum anthropi can catalyze reactions with non‐natural β3‐peptides and β3‐amino acid amides. Here we report that these exceptional enzymes are also able to utilize synthetic dipeptides with N‐terminal β2‐amino acid residues as substrates under aqueous conditions. The suitability of a β2‐peptide as a substrate for BapA or DmpA was strongly dependent on the size of the Cα substituent of the N‐terminal β2‐amino acid. BapA was shown to convert a diastereomeric mixture of the β2‐peptide H‐β2hPhe‐β2hAla‐OH, but did not act on diastereomerically pure β2,β3‐dipeptides containing an N‐terminal β2‐homoalanine. In contrast, DmpA was only active with the latter dipeptides as substrates. BapA‐catalyzed transformation of the diastereomeric mixture of H‐β2hPhe‐β2hAla‐OH proceeded along two highly S‐enantioselective reaction routes, one leading to substrate hydrolysis and the other to the synthesis of coupling products. The synthetic route predominated even at neutral pH. A rise in pH of three log units shifted the synthesis‐to‐hydrolysis ratio (vS/vH) further towards peptide formation. Because the equilibrium of the reaction lies on the side of hydrolysis, prolonged incubation resulted in the cleavage of all peptides that carried an N‐terminal β‐amino acid of S configuration. After completion of the enzymatic reaction, only the S enantiomer of β2‐homophenylalanine was detected (ee>99 % for H‐(S)‐β2‐hPhe‐OH, E>500); this confirmed the high enantioselectivity of the reaction. Our findings suggest interesting new applications of the enzymes BapA and DmpA for the production of enantiopure β2‐amino acids and the enantioselective coupling of N‐terminal β2‐amino acids to peptides.
Giant Vesicles: Preparations and Applications
Authors: Walde Peter , Cosentino Katia , Engel Helen , Stano Pasquale 
Published: March 2010

AbstractThere is considerable interest in preparing cell‐sized giant unilamellar vesicles from natural or nonnatural amphiphiles because a giant vesicle membrane resembles the self‐closed lipid matrix of the plasma membrane of all biological cells. Currently, giant vesicles are applied to investigate certain aspects of biomembranes. Examples include lateral lipid heterogeneities, membrane budding and fission, activities of reconstituted membrane proteins, or membrane permeabilization caused by added chemical compounds. One of the challenging applications of giant vesicles include gene expressions inside the vesicles with the ultimate goal of constructing a dynamic artificial cell‐like system that is endowed with all those essential features of living cells that distinguish them from the nonliving form of matter. Although this goal still seems to be far away and currently difficult to reach, it is expected that progress in this and other fields of giant vesicle research strongly depend on whether reliable methods for the reproducible preparation of giant vesicles are available. The key concepts of currently known methods for preparing giant unilamellar vesicles are summarized, and advantages and disadvantages of the main methods are compared and critically discussed.
Dynamic leadership development in community college administration: Theories, applications, and implications
Authors: Basham Matthew J. , Mathur Raghu P. 
Published: March 2010

AbstractLeaders and managers in community colleges need to be flexible in their everyday job roles and responsibilities. Teams are widely used to serve specific purposes in community college administration. Adopting the research of several Harvard scholars, the authors remind community college administrators when creating dynamic teams to keep a careful balance of leaders and managers.
Beyond the headlines: Wounding and the community college presidency
Authors: Floyd Deborah L. , Maslin‐Ostrowski Pat , Hrabak Michael R. 
Published: March 2010

AbstractA framework for understanding the human side of leadership, especially wounding and leadership struggles, is described with an emphasis on stories of community college presidents. Practical advice and recommendations are offered to better equip aspiring and practicing community college presidents for leadership challenges. A key message is that when a leader experiences a crisis, this stressful situation can be used as an opportunity to learn and grow.
Epilogue: Change leadership and leadership development
Authors: Cloud Robert C. 
Published: March 2010

AbstractChange leadership and leadership development are critically important to the continuing success of public community colleges everywhere. Transactional and transformational leadership, the more traditional models, are no longer adequate to meet the pressing financial and operational challenges in two‐year institutions. Current and aspiring leaders must understand the culture of change that permeates community college campuses and embrace the opportunities inherent in that culture.
Gypsum Crystallization in the Presence of Cr3+ and Citric Acid
Authors: Sargut S. T. , Sayan P. , Kiran B. 
Published: March 2010

AbstractReactive crystallization of calcium sulfate dihydrate (gypsum) was investigated at pH 3.5 and 65 °C in the presence of citric acid and Cr3+ ions. Concentrations of both additives varied between 0 and 4000 ppm. The combined effect of additives on crystal size distributions, filtration characteristics, and crystal morphology were investigated and discussed. It was found that the effect of citric acid on gypsum morphology was suppressed in the presence of Cr3+ ions. The change of morphology is related to the complex formation between Cr3+ ions and citric acid at high ion concentrations.
Effect of Sonocrystallization on the Habit and Structure of Gemfibrozil Crystals
Authors: Ambrus R. , Amirzadi N. N. , Sipos P. , Szabó‐Révész P. 
Published: March 2010

AbstractSpecially engineered drug particles can solve solubility and formulation problems, which are major challenges for the pharmaceutical industry. Ultrasound irradiation induces acoustic streaming, and highly localized temperature and pressure within the fluid, which can lead to a reduction in crystal size and the inhibition of agglomeration. This study covers properties inherent to particle engineering as well as methods for microparticle production and characterization. Melt emulsification and solvent diffusion using ultrasound to complete with drying are presented on the example of poorly water‐soluble Gemfibrozil. Differences in particle size were found depending on the processing parameters applied. During structural characterizations, strong interactions were detected between the drug and the stabilizers. Amorphous or crystalline Gemfibrozil could be obtained.
New Crystalline Solvates of Atorvastatin Calcium
Authors: Jin Y. S. , Ulrich J. 
Published: March 2010

AbstractAtorvastatin calcium (ATC) is widely prescribed as a cholesterol‐lowering agent and is presently the world's best‐selling medicine. A large number of crystalline forms of ATC have been published in patents. In this work, two new crystalline solvates were discovered. Common crystallization methods were used to generate these forms from amorphous ATC. The following methods were applied for characterization: XRPD, DSC, TG, optical microscopy and FT‐Raman spectroscopy. The analytical results were distinct from those of the previously reported crystalline polymorphs, solvates and amorphous forms.
Insight into Crystallization Mechanisms of Polymorphic Hydrate Systems
Authors: Tian F. , Qu H. , Louhi‐Kultanen M. , Rantanen J. 
Published: March 2010

AbstractPolymorphic anhydrate systems have been well studied but until now little attention has been paid to polymorphic hydrate systems. The incorporation of water molecules can complicate the whole polymorphic system and thus impede the control of the crystallization process. In this work, nitrofurantoin monohydrate polymorphs which have the same chemical composition and molar ratio of water but different crystal packing arrangements, have been investigated. The metastable nitrofurantoin monohydrate was found to be difficult to crystallize, where both evaporative and cooling crystallization failed in its production. The possible phase conversion of the nitrofurantoin hydrate polymorphic system was also investigated in a liquid‐assisted ball milling process. High‐energy solids, e.g., amorphous and cocrystals, have often been created during high‐energy ball milling. Metastable nitrofurantoin monohydrate, however, was again not observed during the whole milling process, in contrast to another polymorphic hydrate system, namely niclosamide. During milling of niclosamide anhydrate in ethyl acetate‐water mixture the metastable niclosamide monohydrate was formed immediately upon milling (2 min). Under further milling, the metastable niclosamide hydrate started converting to the stable niclosamide hydrate (from 30 min onwards).
Chromatography‐Crystallization Hybrid Process for Artemisinin Purification from Artemisia annua
Authors: Qu H. , Christensen K. B. , Fretté X. C. , Tian F. , Rantanen J. , Christensen L. P. 
Published: March 2010

AbstractThe feasibility of using a chromatography‐crystallization hybrid separation process for isolation and purification of artemisinin from the herbal plant Artemisia annua was studied. After separating the crude extracts of Artemisia annua by flash column chromatography, a two‐step antisolvent crystallization process was used for further isolation and purification. The two‐step antisolvent crystallization process was designed based on the solubility of artemisinin in different solvents and solvent mixtures. The first step crystallization process was to remove impurities from the solution and the second step to isolate artemisinin. The crystallization behavior of the two polymorphs of artemisinin during the antisolvent crystallization process was also studied by performing crystallization in solutions of artemisinin in acetonitrile and acetone, respectively. It was observed that the formation of the two polymorphs of artemisinin in acetone solution follows the Ostwald's rule of stages. Fast feeding of the antisolvent (water) resulted in crystallization of the metastable triclinic form which then transformed to the stable orthorhombic form through a solvent‐mediated transformation mechanism. The stable orthorhombic form crystallized out when water was fed slowly. Crystallization from acetonitrile always yielded the stable orthorhombic form regardless of the feeding rate of the antisolvent. Finally, a chromatography‐crystallization hybrid separation process was proposed and tested. The results of the present work demonstrated the feasibility of combining the advantages of column chromatography and crystallization to improve efficiency of the isolation of artemisinin from Artemisia annua.