bluuebunny/crossref_metadata_2025 huggingface dataset:
Site‐specific basal body duplication in Chlamydomonas
Authors: O'Toole Eileen T. , Dutcher Susan K.
Published: October 2013

Correct centriole/basal body positioning is required for numerous biological processes, yet how the cell establishes this positioning is poorly understood. Analysis of centriolar/basal body duplication provides a key to understanding basal body positioning and function. Chlamydomonas basal bodies contain structural features that enable specific triplet microtubules to be specified. Electron tomography of cultures enriched in mitotic cells allowed us to follow basal body duplication and identify a specific triplet at which duplication occurs. Probasal bodies elongate in prophase, assemble transitional fibers (TF) and are segregated with a mature basal body near the poles of the mitotic spindle. A ring of nine‐singlet microtubules is initiated at metaphase, orthogonal to triplet eight. At telophase/cytokinesis, triplet microtubule blades assemble first at the distal end, rather than at the proximal cartwheel. The cartwheel undergoes significant changes in length during duplication, which provides further support for its scaffolding role. The uni1‐1 mutant contains short basal bodies with reduced or absent TF and defective transition zones, suggesting that the UNI1 gene product is important for coordinated probasal body elongation and maturation. We suggest that this site‐specific basal body duplication ensures the correct positioning of the basal body to generate landmarks for intracellular patterning in the next generation. © 2013 Wiley Periodicals, Inc.
Repeatability, reproducibility, and accuracy of a novel pushbroom hyperspectral system
Authors: Vilaseca Meritxell , Schael Barbara , Delpueyo Xana , Chorro Elisabet , Perales Esther , Hirvonen Tapani , Pujol Jaume
Published: October 2013

This study analyzes the repeatability, reproducibility and accuracy of a new hyperspectral system based on a pushbroom sensor as a means of measuring spectral features and color of materials and objects. The hyperspectral system consisted of a CCD camera, a spectrograph and an objective lens. An additional linear moving system allowed the mechanical scanning of the complete scene. A uniform overhead luminaire with daylight configuration was used to irradiate the scene using d:45 geometry. We followed the guidelines of the ASTM E2214‐08 Standard Practice for Specifying and Verifying the Performance of Color‐Measuring Instruments that define the standards and latest multidimensional procedures. The results obtained are analyzed in‐depth and compared to those recently reported by other authors for spectrophotometers and multispectral systems. It can be concluded that hyperspectral systems are reliable and can be used in the industry to perform spectral and color readings with a high spatial resolution. © 2013 Wiley Periodicals, Inc. Col Res Appl, 39, 549–558, 2014
Visible‐near infrared concealment of cotton/nylon fabrics using colored pigments and multiwalled carbon nanotube particles (MWCNTs)
Authors: Khajeh Mehrizi M. , Bokaei F. , Jamshidi N.
Published: October 2013

To match the reflectance profile of desert colors including dark brown, light brown and olive green in the visible‐near IR (Vis‐NIR) bands, five selected colored pigments were utilized to print woven cotton/nylon fabrics. Multi‐walled carbon nanotube particles (MWCNT's) were also added to some of the printing pastes. The reflectance of printed fabrics was evaluated by using spectrophotometric technique. The effect of adding MWCNT's, on washing; light and crocking fastness alongside with colorimetric values of printed samples was evaluated. Furthermore, the water absorption time was measured in order to determine wettability of each printed sample. The results demonstrated that the presence of MWCNT's in concentration range of 0.04–0.12 g kg−1 in printing formulations was found to cause considerable decline in Near Infrared (NIR) reflectance while a surprising increase in visible reflectance of samples was observed. Color characteristics of printed fabrics were noticeably changed even at concentrations as low as 0.12 g kg−1 MWCNTs in printing formulations. Presence of MWCNTs in printing formulations was found to cause a significant increase in wetting time of samples. Also, the results indicated that air permeability of printed samples containing MWCNT's were higher than samples printed with no MWCNTs. Phenomena imposed by MWCNT's presence on pigment printed samples showed very good fastness levels in crocking, washing and light fastness tests. In dark brown sample, adding MWCNTs to the pigment printing pastes could tune the overall reflectance in order to match the standard reflectance profile accepted for use in concealment color of desert areas. © 2013 Wiley Periodicals, Inc. Col Res Appl, 40, 93–98, 2015
Workplace drug testing and alcohol policy in Italy; there is still a long way to go
Authors: Rosso Gian Luca , Perotto Massimo , Feola Mauro , Caramella Michele
Published: October 2013

The effectiveness of workplace drug testing (WDT) in Italy has recently been questioned, while very little is known about the real consumption of alcoholic beverages among workers performing hazardous jobs, such as professional drivers (PDs). The aim of this study is to investigate the modality and frequency of WDT execution and of alcohol consumption in the above category. Anonymous questionnaires were used to collect information. Four hundred and ninety‐seven questionnaires were collected; 50.1% declared that they know well in advance when they will be subjected to screening tests for drugs, while 19.5% claimed they have never been subjected to such a test. The greater the number of employees in a company, the greater the likelihood that the tests are performed with a genuinely surprise effect [odds ratio (OR) 2.41, 5.39 and 9.07, respectively, for businesses with 5–14 employees, 15–50 and more than 50, compared with companies with less than 5 employees, p <0.01]. Twenty‐one point four percent declared they drink alcoholic beverages during working hours or work breaks. This attitude is positively correlated with driver seniority [OR 1.07, 95% confidence interval (CI) 1.03–1.11 p <0.01] and is more common in those who operate on mainly international routes (OR 3.34 CI 1.30–8.59 p <0.01) and only occasionally consume meals in restaurants (OR 4.27, CI 1.19–15.42 p <0.05). Fifteen percent of the participants have an AUDIT C score ≥ 5. In conclusion WDT is largely ineffective, particularly in small businesses. The high percentage of PDs who claim to drink during working hours and who are hazardous drinkers requires a further strengthening of prevention strategies in this area. Copyright © 2013 John Wiley & Sons, Ltd.
Angiotensin II type 2 receptor regulates the development of pancreatic endocrine cells in mouse embryos
Authors: Leung Kwan Keung , Liang Juan , Zhao Shuiling , Chan Wood Yee , Leung Po Sing
Published: October 2013

Background: We previously identified a local renin‐angiotensin system (RAS) regulating the differentiation of an isolated population of human pancreatic progenitor cells. Major RAS components that regulate organogenesis have been also described in embryos; however, it is not known whether a local RAS is present in the fetal pancreas. We now hypothesize that angiotensin II type 1 (AT1) and type 2 (AT2) receptors are expressed in mouse embryonic pancreas and involved in regulating endocrine cell development. Results: Differential expression of AT1 and AT2 receptors was observed in the mouse pancreata in late embryogenesis. Systemic AT2, but not AT1, receptor blockade during the second transition in pancreatic development (from embryonic day 12.0 onward) reduced the β‐cell to α‐cell ratio of the neonate islets, impaired their insulin secretory function and the glucose tolerance of the pups. Studies with pancreas explants ex vivo revealed regulation by AT2 receptors of the differentiation of pancreatic progenitors into insulin‐producing cells and of the proliferation of the differentiated cell, actions that did not result from reduced angiogenesis as a secondary effect of AT2 receptor antagonism. Conclusions: These data revealed an AT2 receptor‐mediated mechanism regulating pancreatic endocrine cell development in vivo. Developmental Dynamics 243:415–427, 2014. © 2013 Wiley Periodicals, Inc.
Embryonic expression of the transforming growth factor beta ligand and receptor genes in chicken
Authors: Cooley James R. , Yatskievych Tatiana A. , Antin Parker B.
Published: October 2013

Background: Transforming growth factor‐beta (TGFβ) signaling regulates a myriad of biological processes during embryogenesis, in the adult, and during the manifestation of disease. TGFβ signaling is propagated through one of three TGFβ ligands interacting with Type I and Type II receptors, and Type III co‐receptors. Although TGFβ signaling is regulated partly by the combinatorial expression patterns of TGFβ receptors and ligands, a comprehensive gene expression analysis has not been published. Results: Here we report the embryonic mRNA expression patterns in chicken embryos of the canonical TGFβ ligands (TGFB1, TGFB2, and TGFB3) and receptors (TGFBR1, TGFBR2, TGFBR3), plus the Activin A receptor, type 1 (ACVR1) and co receptor Endoglin (ENG) that also transduce TGFβ signaling. Conclusions: TGFB ligands and receptors show dynamic and frequently overlapping expression patterns in numerous embryonic cell layers and structures. Integrating expression information identifies combinations of ligands and receptors that are involved in specific developmental processes including somitogenesis, cardiogenesis and vasculogenesis. Developmental Dynamics 243:497–508, 2014. © 2013 Wiley Periodicals, Inc.
The embryogenesis of the Tick Rhipicephalus (Boophilus) microplus: The establishment of a new chelicerate model system
Authors: Santos Vitória Tobias , Ribeiro Lupis , Fraga Amanda , de Barros Cíntia Monteiro , Campos Eldo , Moraes Jorge , Fontenele Marcio Ribeiro , Araújo Helena Marcolla , Feitosa Natalia Martins , Logullo Carlos , da Fonseca Rodrigo Nunes
Published: October 2013

Summary: Chelicerates, which include spiders, ticks, mites, scorpions, and horseshoe crabs, are members of the phylum Arthropoda. In recent years, several molecular experimental studies of chelicerates have examined the embryology of spiders; however, the embryology of other groups, such as ticks (Acari: Parasitiformes), has been largely neglected. Ticks and mites are believed to constitute a monophyletic group, the Acari. Due to their blood‐sucking activities, ticks are also known to be vectors of several diseases. In this study, we analyzed the embryonic development of the cattle tick, Rhipicephalus (Boophilus) microplus (Acari: Ixodidae). First, we developed an embryonic staging system consisting of 14 embryonic stages. Second, histological analysis and antibody staining unexpectedly revealed the presence of a population of tick cells with similar characteristics to the spider cumulus. Cumulus cell populations also exist in other chelicerates; these cells are responsible for the breaking of radial symmetry through bone morphogenetic protein signaling. Third, it was determined that the posterior (opisthosomal) embryonic region of R. microplus is segmented. Finally, we identified the presence of a transient ventral midline furrow and the formation and regression of a fourth leg pair; these features may be regarded as hallmarks of late tick embryogenesis. Importantly, most of the aforementioned features are absent from mite embryos, suggesting that mites and ticks do not constitute a monophyletic group or that mites have lost these features. Taken together, our findings provide fundamental common ground for improving knowledge regarding tick embryonic development, thereby facilitating the establishment of a new chelicerate model system. genesis 51:803–818. © 2013 Wiley Periodicals, Inc.
PD‐1 modulates steady‐state and infection‐induced IL‐10 production in vivo
Authors: McBerry Cortez , Dias Alexandra , Shryock Nathaniel , Lampe Kristin , Gutierrez Fredy R. S. , Boon Louis , Herbert De'Broski R. , Aliberti Julio
Published: October 2013

Programmed death‐1 (PD‐1) plays an important role in mediating immune tolerance through mechanisms that remain unclear. Herein, we investigated whether PD‐1 prevents excessive host tissue damage during infection with the protozoan parasite, Toxoplasma gondii. Surprisingly, our results demonstrate that PD‐1‐deficient mice have increased susceptibility to T. gondii, with increased parasite cyst counts along with reduced type‐1 cytokine responses (IL‐12 and IFN‐γ). PD‐1−/− DCs showed no cell intrinsic defect in IL‐12 production in vitro. Instead, PD‐1 neutralization via genetic or pharmacological approaches resulted in a striking increase in IL‐10 release, which impaired type‐1‐inflammation during infection. Our results indicate that the absence of PD‐1 increases IL‐10 production even in the absence of infection. Although the possibility that such increased IL‐10 protects against autoimmune damage is speculative, our results show that IL‐10 suppresses the development of protective Th1 immune response after T. gondii infection.
Immune activation by histones: Plusses and minuses in inflammation
Authors: Pisetsky David S.
Published: October 2013

Histones are highly cationic proteins that are essential components of the cell nucleus, interacting with DNA to form the nucleosome and regulating transcription. Histones, however, can transit from the cell nucleus during cell death and, once in an extracellular location, can serve as danger signals and activate immune cells. An article in this issue of the European Journal of Immunology [Eur. J. Immunol. 2013. 43: 3336–3342] reports that histones can activate monocyte‐derived DCs via the NRLP3 inflammasome to induce the production of IL‐1β. As such, histones, which can also stimulate TLRs, may drive events in the immunopathogenesis of a wide range of acute and chronic diseases marked by sterile inflammation. While the mechanism of this stimulation is not known, the positive charge of histones may provide a structural element to promote interaction with cells and activation of downstream signaling systems.
Efficient algorithm for simulation of isoelectric focusing
Authors: Yoo Kisoo , Shim Jaesool , Liu Jin , Dutta Prashanta
Published: October 2013

IEF simulation is an effective tool to investigate the transport phenomena and separation performance as well as to design IEF microchip. However, multidimensional IEF simulations are computationally intensive as one has to solve a large number of mass conservation equations for ampholytes to simulate a realistic case. In this study, a parallel scheme for a 2D IEF simulation is developed to reduce the computational time. The calculation time for each equation is analyzed to identify which procedure is suitable for parallelization. As expected, simultaneous solution of mass conservation equations of ampholytes is identified as the computational hot spot, and the computational time can be significantly reduced by parallelizing the solution procedure for that. Moreover, to optimize the computing time, electric potential behavior during transient state is investigated. It is found that for a straight channel the transient variation of electric potential along the channel is negligible in a narrow pH range (5∼8) IEF. Thus the charge conservation equation is solved for the first time step only, and the electric potential obtain from that is used for subsequent calculations. IEF simulations are carried out using this algorithm for separation of cardiac troponin I from serum albumin in a pH range of 5–8 using 192 biprotic ampholytes. Significant reduction in simulation time is achieved using the parallel algorithm. We also study the effect of number of ampholytes to form the pH gradient and its effect in the focusing and separation behavior of cardiac troponin I and albumin. Our results show that, at the completion of separation phase, the pH profile is stepwise for lower number of ampholytes, but becomes smooth as the number of ampholytes increases. Numerical results also show that higher protein concentration can be obtained using higher number of ampholytes.
Dynamic microparticle manipulation with an electroosmotic flow gradient in low‐frequency alternating current dielectrophoresis
Authors: Gencoglu Aytug , Olney David , LaLonde Alexandra , Koppula Karuna S. , Lapizco‐Encinas Blanca H.
Published: October 2013

In this study, the potential of low‐frequency AC insulator‐based DEP (iDEP) was explored for the separation of polystyrene microparticles and yeast cells. An EOF gradient was generated by employing an asymmetrical, 20 Hz AC electrical signal in an iDEP device consisting of a microchannel with diamond‐shaped insulating posts. Two types of samples were analyzed, the first sample contained three types of polystyrene particles with different diameters (0.5, 1.0, and 2.0 μm) and the second sample contained two types of polystyrene particles (1.0 and 2 μm) and yeast cells (6.3 μm). This particular scheme uses a tapered AC signal that allows for all particles to be trapped and concentrated at the insulating post array, as the signal becomes asymmetrical (more positive), particles are selectively released. The smallest particles in each sample were released first, since they require greater dielectrophoretic forces to remain trapped. The largest particles in each sample were released last, when the applied signal became cyclical. A dielectropherogram, which is analogous to a chromatogram, was obtained for each sample, demonstrating successful separation of the particles by showing “peaks” of the released particles. These separations were achieved at lower applied potentials than those reported in previous studies that used solely direct current electrical voltages. Additionally, mathematical modeling with COMSOL Multiphysics was carried out to estimate the magnitude of the dielectrophoretic and EOF forces acting on the particles considering the low‐frequency, asymmetrical AC signal used in the experiments. The results demonstrated the potential of low‐frequency AC‐iDEP systems for handling and separating complex mixtures of microparticles and biological cells.
Capillary electrophoresis separation of the desamino degradation products of oxytocin
Authors: Creamer Jessica S. , Krauss Shannon T. , Lunte Susan M.
Published: October 2013

Oxytocin (OT) is an endogenous and therapeutic hormone necessary for maternal health. It is also the subject of fast growing research in the field of behavioral science. This article describes a rapid CE method using UV detection at 214 nm for the determination of the deamidation products of OT. Deamidation is the most common degradation pathway of peptides and proteins and can lead to reduced therapeutic efficiency of biopharmaceuticals. To achieve a separation of the seven structurally similar desamino peptides from OT, 11 mM sulfobutyl ether β‐CD and 10% v/v MeOH were added to a BGE of 50 mM phosphate buffer at pH 6.0. The assay is linear within ≤5–100 μM for all species with a total analysis time of 12 min. The method was then applied to monitor the heat‐stress degradation of OT at 70°C, where all seven desamino species were observed over a 96 h period.
Mass transfer of a neutral solute in porous microchannel under streaming potential
Authors: Mondal Sourav , De Sirshendu
Published: October 2013

The mass transport of a neutral solute in a porous wall, under the influence of streaming field, has been analyzed in this study. The effect of the induced streaming field on the electroviscous effect of the fluid for different flow geometries has been suitably quantified. The overall electroosmotic velocity profile and expression for streaming field have been obtained analytically using the Debye–Huckel approximation, and subsequently used in the analysis for the mass transport. The analysis shows that as the solution Debye length increases, the strength of the streaming field and, consequently, the electroviscous effect diminishes. The species transport equation has been coupled with Darcy's law for quantification of the permeation rate across the porous wall. The concentration profile inside the mass transfer boundary layer has been solved using the similarity transformation, and the Sherwood number has been calculated from the definition. In this study, the variation of the permeation rate and solute permeate concentration has been with the surface potential, wall retention factor and osmotic pressure coefficient has been demonstrated for both the circular as well as rectangular channel cross‐section.
Speciation analysis of mercury in water samples by dispersive liquid–liquid microextraction coupled to capillary electrophoresis
Authors: Yang Fangfang , Li Jinhua , Lu Wenhui , Wen Yingying , Cai Xiaoqiang , You Jinmao , Ma Jiping , Ding Yangjun , Chen Lingxin
Published: October 2013

In this study, a method of pretreatment and speciation analysis of mercury by dispersive liquid–liquid microextraction along with CE was developed. The method was based on the fact that mercury species including methylmercury (MeHg), ethylmercury (EtHg), phenylmercury (PhHg), and Hg(II) were complexed with 1‐(2‐pyridylazo)‐2‐naphthol to form hydrophobic chelates and l‐cysteine could displace 1‐(2‐pyridylazo)‐2‐naphthol to form hydrophilic chelates with the four mercury species. Factors affecting complex formation and extraction efficiency, such as pH value, type, and volume of extractive solvent and disperser solvent, concentration of the chelating agent, ultrasonic time, and buffer solution were investigated. Under the optimal conditions, the enrichment factors were 102, 118, 547, and 46, and the LODs were 1.79, 1.62, 0.23, and 1.50 μg/L for MeHg, EtHg, PhHg, and Hg(II), respectively. Method precisions (RSD, n = 5) were in the range of 0.29–0.54% for migration time, and 3.08–7.80% for peak area. Satisfactory recoveries ranging from 82.38 to 98.76% were obtained with seawater, lake, and tap water samples spiked at three concentration levels, respectively, with RSD (n = 5) of 1.98–7.18%. This method was demonstrated to be simple, convenient, rapid, cost‐effective, and environmentally benign, and could be used as an ideal alternative to existing methods for analyzing trace residues of mercury species in water samples.
Microfluidic chip‐based liquid chromatography coupled to mass spectrometry for determination of small molecules in bioanalytical applications: An update
Authors: Lin Shu‐Ling , Lin Tzuen‐Yeuan , Fuh Ming‐Ren
Published: October 2013

Many microfluidic chip‐based LC‐MS systems have been utilized for high‐throughput analysis in various fields of bioanalytical applications such as proteomic, glycomic, pharmaceutical, and clinical research. This review is an update of a previous review article (Electrophoresis 2012, 33, 635–643) to mainly cover the most recent advancements in chip‐based LC‐MS for determining small molecules in bioanalysis. First, the different types of microfluidic chip devices for chip‐based LC‐MS analysis will be discussed. Following the discussion of the recent developments in the chip‐based instrumentation, the applications of chip‐based LC‐MS for determining small molecules, such as glycans, pharmaceutical drugs, drugs of abuse, drug metabolites, and biomarkers in various biological sample matrixes will also be included in this review.
Contactless conductivity detector array for capillary electrophoresis
Authors: Stojkovic Marko , Koenka Israel Joel , Thormann Wolfgang , Hauser Peter C.
Published: October 2013

A CE system featuring an array of 16 contactless conductivity detectors was constructed. The detectors were arranged along 70 cm length of a capillary with 100 cm total length and allow the monitoring of separation processes. As the detectors cannot be accommodated on a conventional commercial instrument, a purpose built set‐up employing a sequential injection manifold had to be employed for automation of the fluid handling. Conductivity measurements can be considered universal for electrophoresis and thus any changes in ionic composition can be monitored. The progress of the separation of Na+ and K+ is demonstrated. The potential of the system to the study of processes in CZE is shown in two examples. The first demonstrates the differences in the developments of peaks originating from a sample plug with a purely aqueous background to that of a plug containing the analyte ions in the buffer. The second example visualizes the opposite migration of cations and anions from a sample plug that had been placed in the middle of the capillary.
Enhanced information throughput in multiple input multiple output orthogonal frequency division multiplexing based systems using fractional sampling and iterative signal processing
Authors: Sharma Shree Krishna , Patwary Mohammad , Abdel‐Maguid Mohamed
Published: October 2013

Herein, we study the feasibility of enhanced information throughput capability of multiple input multiple output orthogonal frequency division multiplexing (MIMO‐OFDM) based wireless communication systems in the context of increasing wireless capacity demand. The concept of fractional sampling (FS) is exploited for this purpose to take advantage of diversity created because of it. Furthermore, a novel channel adaptive iterative sequence detector is proposed using the FS technique. The performance analysis of the proposed receiver is carried out, and a tighter performance bound is derived. It is found that the FS technique can improve bit error rate performance of MIMO and OFDM based systems provided that the noise samples are uncorrelated up to a certain level of FS rate. Moreover, it is observed that the performance improvement is a non‐linear function of the FS rate. Besides this, the simulation results show that the proposed iterative receiver can significantly enhance the information throughput of MIMO‐OFDM based wireless communication systems in comparison to conventional non‐iterative receivers. Copyright © 2013 John Wiley & Sons, Ltd.
Frequency allocation game in satisfaction form
Authors: Ellingsæter Brage
Published: October 2013

In this paper, we analyse frequency allocation in wireless networks through a game in satisfaction form. Satisfaction form games are games without any optimisation aspects where a player is either satisfied or not. We show that such a formulation is especially suited for frequency allocation with quality‐of‐service constraints. We investigate different equilibrium concepts and show that there exists a mixed‐strategy distribution where all players are satisfied with a probability not less than a certain threshold. In the case where there exists a pure‐strategy action profile that can achieve satisfaction for all players, we present a learning algorithm that guarantees convergence to this action profile in finite time. In the case that no such pure‐strategy action profile exists, we show that the satisfaction form formulation possesses an action profile yielding higher utility for unsatisfied players compared with a normal form game. Lastly we show extensive simulation results that highlight the differences between a frequency allocation game in satisfaction form compared with other game formulations. Copyright © 2013 John Wiley & Sons, Ltd.
Information‐centric networking and multimedia services: present and future challenges
Authors: Piro Giuseppe , Grieco Luigi Alfredo , Boggia Gennaro , Chatzimisios Periklis
Published: October 2013

The emerging information‐centric networking (ICN) paradigm is gaining worldwide the attention of academia and industrial research communities, thanks to its inherent ability to support also the next generation information and communication technology services beyond the current host‐centric Internet rationale. In this context, significant scientific efforts are being devoted to the investigation of ICN‐based multimedia systems because they represent the most popular use case for Internet users. In order to offer a unifying view on such valuable contributions, this paper presents a thorough review of the state of the art, a comprehensive framework to classify the most significant proposals, an overlook at the road ahead towards mature ICN‐based multimedia systems and a critical discussion on available tools. Our final wish is twofold: from one hand, this paper will provide a useful starting point for beginners in the field; whereas, from the other hand, it will help researchers already working on ICN‐related topics in finding a common agreement on participated scientific activities. Copyright © 2013 John Wiley & Sons, Ltd.
The PTEN inhibitor bisperoxovanadium enhances myelination by amplifying IGF‐1 signaling in rat and human oligodendrocyte progenitors
Authors: De Paula Marcio L. , Cui Qiao‐Ling , Hossain Shireen , Antel Jack , Almazan Guillermina
Published: October 2013

Oligodendrocytes (OLGs) produce and maintain myelin in the central nervous system (CNS). In the demyelinating autoimmune disease multiple sclerosis, OLGs are damaged and those remaining fail to fully remyelinate CNS lesions. Therefore, current therapies directed to restrain the inflammation process with approaches that protect and reconstitute oligodendrocyte density would be essential to pave the way of myelin repair. A critical signal for oligodendrocytes is insulin‐like growth factor‐1 (IGF‐1), which promotes their development and ultimately myelin formation. PTEN inhibits the phosphoinositide 3‐kinase (PI3K)/Akt signaling, a convergence downstream pathway for growth factors such as IGF‐1. In this report, we temporarily inhibited PTEN activity by treating rat and human oligodendrocyte progenitors (OLPs) cultured alone or with dorsal root ganglion neurons (DRGNs) with bisperoxovanadium (phen). Our findings show that phen potentiates IGF‐1 actions by increasing proliferation of OLPs in a concentration‐dependent manner, and caused a sustained and time‐dependent activation of the main pathways: PI3K/Akt/mammalian target of rapamycin (mTOR) and MEK/ERK. At low concentrations, IGF‐1 and phen stimulated the differentiation of rat and human OLPs. Concordantly, the PTEN inhibitor together with IGF‐1 robustly augmented myelin basic protein accumulation in rat newborn and human fetal OLGs co‐cultured with DRGNs in a longer timeframe by promoting the elaboration of organized myelinated fibers as evidenced by confocal microscopy. Thus, our results suggest that a transient suppression of a potential barrier for myelination in combination with other therapeutic approaches including growth factors may be promising to improve the functional recovery of CNS injuries. GLIA 2013;62:64–77
Effective down‐regulation of signal transducer and activator of transcription 3 (STAT3) by polyplexes of siRNA and lipid‐substituted polyethyleneimine for sensitization of breast tumor cells to conventional chemotherapy
Authors: Falamarzian Arash , Montazeri Aliabadi Hamidreza , Molavi Ommoleila , Seubert John M. , Lai Raymond , Uludağ Hasan , Lavasanifar Afsaneh
Published: October 2013

Signal transducer and activator of transcription 3 (STAT3) is a transcription factor that plays a major role in the development of resistance to conventional anti‐cancer drugs in many types of cancer, when constitutively activated. Inhibition of STAT3 is considered as a promising strategy for inhibition of tumor growth and overcoming the drug resistance manifested. In this study, the capability of STAT3 knockdown by lipid substituted low molecular weight (2 kDa) polyethyleneimine (PEI2) complexes of STAT3–siRNA was assessed. The efficiency of PEI/STAT3‐siRNA polyplexes in the induction of STAT3 associated cell death in wild type and drug‐resistant MDA‐MB‐435 breast cancer cells as monotherapy and upon combination with chemotherapeutic agents, doxorubicin and paclitaxel, was also investigated. Our results identified linoleic acid‐substituted (PEI‐LA) polymer as the most efficient carrier among different lipid substituted PEI2 for siRNA delivery, leading to most STAT3 associated loss of cell viability in MDA‐MB‐435 cells. STAT3‐siRNA delivery by the PEI‐LA polymer resulted in efficient down‐regulation of STAT3 at both mRNA and protein levels. Furthermore, pre‐treatment of cancer cells with STAT3–siRNA formulation increased the cytotoxic effect of doxorubicin and paclitaxel in both wild type and drug resistant MDA‐MB‐435 cells. The results of this study point to the potential of PEI‐LA polyplexes of STAT3–siRNA as inhibitors of STAT3 expression in breast tumor cells. The results also demonstrate an improved efficacy for chemotherapeutic drugs in combination with lipid‐substituted low molecular weight PEI‐LA/STAT3‐siRNA complexes in comparison to drug therapy alone. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 3216–3228, 2014.
Silica coating of the pore walls of a microporous polycaprolactone membrane to be used in bone tissue engineering
Authors: Demirdögen B. , Plazas Bonilla C. E. , Trujillo S. , Perilla J. E. , Elcin A. E. , Elcin Y. M. , Gómez Ribelles J. L.
Published: October 2013

Polycaprolactone/silica microporous hybrid membranes were produced in two steps: A microporous polycaprolactone membrane with an interconnected porosity of 80% was obtained via a freeze extraction procedure, then silica was formed by a sol–gel reaction inside the micropores using tetraethyl orthosilicate, TEOS, as silica precursor. It is shown that silica forms a thin coating layer homogeneously distributed over the pore walls when sol–gel reaction is catalyzed by hydrochloric acid, while it forms submicron spherical particles when using basic catalyzer. Some physical properties and the viability and osteoblastic differentiation of bone marrow rat mesenchymal stem cells cultured on pure and hybrid membranes were studied. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 3229–3236, 2014.
Antibacterial activity of silver: The role of hydrodynamic particle size at nanoscale
Authors: Khurana Chandni , Vala Anjana K. , Andhariya Nidhi , Pandey O. P. , Chudasama Bhupendra
Published: October 2013

Silver shows the highest antimicrobial activities amongst all metals. It is better than many first line antibiotics. The antimicrobial properties of silver can be tuned by altering its physical and surface properties. Researchers have demonstrated enhancement in the antibacterial properties of silver with decreasing particle size from bulk to nano. In the present article, we study the effect of particle size of silver at nanoscale on their antimicrobial properties. Two samples of silver nanoparticles (SNPs) of same physical size (≈8 nm) but different hydrodynamic size (59 and 83 nm) are prepared by chemical reduction of AgNO3 with oleylamine followed by phase transfer with triblock copolymer Pluronic F‐127. Their antimicrobial properties are investigated by microdilution method against clinically important strains of gram positive (S. aureus and B. megaterium) and gram negative (P. vulgaris and S. sonnei) bacteria. Nearly 38–50% enhancement in the antibacterial action of SNPs was observed when their hydrodynamic size was reduced to 59 nm from 83 nm. It has been observed that the antibacterial action of SNPs was governed by their hydrodynamic size and not by their crystallite and physical size. The phenomenological model was also proposed which makes an attempt to explain the microscopic mechanism responsible for the size dependent antibacterial activities of silver. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 3361–3368, 2014.
Macrophage responses to a Zr‐based bulk metallic glass
Authors: Huang Lu , Zhang Tao , Liaw Peter K. , He Wei
Published: October 2013

Bulk metallic glasses (BMGs) are considered to be a competitive candidate of biomedical materials, owing to their appealing mechanical properties and high thermal processability. Based on the established biosafety of the Zr‐based BMGs, macrophage responses to (Zr55Al10Ni5Cu30)99Y1 (atomic percent) BMG were investigated in the present study, in comparison with Ti‐6Al‐4V alloy. The adhesion of RAW 264.7 macrophages to both alloys was found to be mediated by protein adsorption. The Zr‐based BMG is capable of supporting regular adhesion and proliferation of macrophages, indicating its good biocompatibility, which agrees with previous findings using other mammalian cells. A lower degree of morphological activation was revealed on Zr‐based BMG substrates than on Ti‐6Al‐4V substrates, which is evidenced by smaller spreading areas and less ruffling on cell surfaces. Smaller amount of proinflammatory cytokine, tumor necrosis factor‐alpha, was secreted by macrophages cultured on Zr‐based BMGs, which further confirms the lower level of inflammation induced by BMG than by Ti alloys. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 3369–3378, 2014.
Role of TGF-β in a Mouse Model of High Turnover Renal Osteodystrophy
Authors: Liu Shiguang , Song Wenping , Boulanger Joseph H , Tang Wen , Sabbagh Yves , Kelley Brian , Gotschall Russell , Ryan Susan , Phillips Lucy , Malley Katie , Cao Xiaohong , Xia Tai-He , Zhen Gehua , Cao Xu , Ling Hong , Dechow Paul C , Bellido Teresita M , Ledbetter Steven R , Schiavi Susan C
Published: October 2013

Altered bone turnover is a key pathologic feature of chronic kidney disease-mineral and bone disorder (CKD-MBD). Expression of TGF-β1, a known regulator of bone turnover, is increased in bone biopsies from individuals with CKD. Similarly, TGF-β1 mRNA and downstream signaling is increased in bones from jck mice, a model of high-turnover renal osteodystrophy. A neutralizing anti-TGF-β antibody (1D11) was used to explore TGF-β's role in renal osteodystrophy. 1D11 administration to jck significantly attenuated elevated serum osteocalcin and type I collagen C-telopeptides. Histomorphometric analysis indicated that 1D11 administration increased bone volume and suppressed the elevated bone turnover in a dose-dependent manner. These effects were associated with reductions in osteoblast and osteoclast surface areas. Micro-computed tomography (µCT) confirmed the observed increase in trabecular bone volume and demonstrated improvements in trabecular architecture and increased cortical thickness. 1D11 administration was associated with significant reductions in expression of osteoblast marker genes (Runx2, alkaline phosphatase, osteocalcin) and the osteoclast marker gene, Trap5. Importantly, in this model, 1D11 did not improve kidney function or reduce serum parathyroid hormone (PTH) levels, indicating that 1D11 effects on bone are independent of changes in renal or parathyroid function. 1D11 also significantly attenuated high-turnover bone disease in the adenine-induced uremic rat model. Antibody administration was associated with a reduction in pSMAD2/SMAD2 in bone but not bone marrow as assessed by quantitative immunoblot analysis. Immunostaining revealed pSMAD staining in osteoblasts and osteocytes but not osteoclasts, suggesting 1D11 effects on osteoclasts may be indirect. Immunoblot and whole genome mRNA expression analysis confirmed our previous observation that repression of Wnt/β-catenin expression in bone is correlated with increased osteoclast activity in jck mice and bone biopsies from CKD patients. Furthermore, our data suggest that elevated TGF-β may contribute to the pathogenesis of high-turnover disease partially through inhibition of β-catenin signaling. © 2014 American Society for Bone and Mineral Research.
Adaptive lambda square dynamics simulation: An efficient conformational sampling method for biomolecules
Authors: Ikebe Jinzen , Sakuraba Shun , Kono Hidetoshi
Published: October 2013

A novel, efficient sampling method for biomolecules is proposed. The partial multicanonical molecular dynamics (McMD) was recently developed as a method that improved generalized ensemble (GE) methods to focus sampling only on a part of a system (GEPS); however, it was not tested well. We found that partial McMD did not work well for polylysine decapeptide and gave significantly worse sampling efficiency than a conventional GE. Herein, we elucidate the fundamental reason for this and propose a novel GEPS, adaptive lambda square dynamics (ALSD), which can resolve the problem faced when using partial McMD. We demonstrate that ALSD greatly increases the sampling efficiency over a conventional GE. We believe that ALSD is an effective method and is applicable to the conformational sampling of larger and more complicated biomolecule systems. © 2013 Wiley Periodicals, Inc.
Suitability of digoxin as a P‐glycoprotein probe: Implications of other transporters on sensitivity and specificity
Authors: Nader Ahmed M. , Foster David R.
Published: October 2013

The study of transporter‐mediated drug–drug interactions (DDI) requires use of appropriate probes to reflect transporter function. Digoxin is often used as a probe in DDI studies involving P‐glycoprotein (P‐gp) and is recommended by FDA for this purpose, despite several lingering questions regarding suitability of digoxin as P‐gp probe. This review aims to critically evaluate use of digoxin as a probe for P‐gp‐mediated clinical DDI studies, with focus on sensitivity and specificity of digoxin for P‐gp. Although previous reviews have evaluated digoxin transport by P‐gp, the purpose of the current review is to critically evaluate such literature in light of newly evolving literature suggesting digoxin transport by non‐P‐gp transporters.
Optimization of SO2‐catalyzed hydrolysis of corncob for xylose and xylitol production
Authors: Fan Xiaoguang , Li Menghua , Zhang Jingkun , Tang Pingwah , Yuan Qipeng
Published: October 2013

BACKGROUND

Conventional techniques for corncob hydrolysis were generally based on acid treatment. However, a large number of by‐products and undesirable compounds released during acid hydrolysis process may act as inhibitors to xylitol fermentation. To replace acid hydrolysis, SO2‐catalyzed hydrolysis was used in this study to improve the fermentability of corncob hemicellulose hydrolysate.

RESULTS

Based on a central composite design (CCD), 20 operations were performed to optimize the process of SO2‐catalyzed hydrolysis by varying SO2 concentration, temperature and reaction time. The optimum condition found for these parameters was 2.16% (wt), 142 °C, 98 min, with 90.51% of the theoretical xylose yield obtained. In a comparison with sulfuric acid hydrolysis, SO2‐catalyzed hydrolysis was proved to be preferable since it resulted in approximately the same sugar yields, but better fermentability. The conversion of xylose to xylitol and volumetric productivity fermented from concentrated SO2‐catalyzed hydrolysate (SCH) were 70.21% and 1.16 g L‐1 h‐1, respectively, higher than those fermented from concentrated sulfuric acid hydrolysate (SAH).

CONCLUSION

Findings suggested that the SO2‐catalyzed hydrolysis strategy can be conveniently and effectively applied to xylose and xylitol production. © 2013 Society of Chemical Industry
Salt‐free production of γ‐aminobutyric acid from glutamate using glutamate decarboxylase separated from Escherichia coli
Authors: Dinh Thu Huong , Ho Ngoc Anh Thu , Kang Taek Jin , McDonald Karen A. , Won Keehoon
Published: October 2013

BACKGROUND

Gamma(γ)‐aminobutyric acid (GABA) has been used extensively in pharmaceuticals and functional foods and is also a building block for bioplastics. GABA is produced from glutamate through decarboxylation catalyzed by glutamate decarboxylase (GAD). The reaction medium should be kept acidic because a pH rise resulting from the reaction inactivates the enzyme catalyst, which is active only at acidic pH. The use of conventional buffers and acids inevitably accompanies salts, which cause serious problems in separation and purification of GABA. In this work, we have applied heterogeneous solid acids for the first time.

RESULTS

The GAD‐catalyzed reaction was conducted in 0.2 mol L−1 sodium acetate buffer (pH 4.6) with 1 mol L−1 monosodium glutamate at 37 °C. When commercial cation‐exchange resins as solid acids were simply added to the reaction medium, the conversion improved from 13% to 67% without salt formation. Even when water was used as the reaction medium, acidic ion‐exchange resins enhanced the reaction conversion significantly.

CONCLUSION

In a salt‐free manner, acidic resins suppress the pH rise during the reaction so that they can enhance the reaction conversion. In addition, they can be recovered and reused easily after the reaction. Heterogeneous solid acids make the GABA production process more economical and eco‐friendly. © 2013 Society of Chemical Industry
Obtaining microbial communities with exoelectrogenic activity from anaerobic sludge using a simplified procedure
Authors: Ribot‐Llobet Edgar , Montpart Nuria , Ruiz‐Franco Yolanda , Rago Laura , Lafuente Javier , Baeza Juan Antonio , Guisasola Albert
Published: October 2013

BACKGROUND

The microbial fuel cell (MFC) technology transforms the chemical energy present in substrates into electricity. Starting‐up these systems, i.e. enriching the anodic community in exoelectrogenic bacteria, is a lengthy process or requires expensive equipment.

RESULTS

An easy and low‐cost procedure based on a sediment MFC was developed to select microbial communities with exoelectrogenic activity from the anaerobic sludge of a waste water treatment plant (WWTP). The configuration was based on a simple vessel working as a single chamber MFC with a cathode of stainless steel wool in the liquid surface and a submerged graphite fibre brush as anode. In 30 days of operation, a biofilm with remarkable exoelectrogenic activity was grown on the anode of the MFC. This graphite fibre brush anode was able to supply 0.9 W m‐2 when working in an air‐cathode MFC (AC‐MFC) for 45 days.

CONCLUSION

The procedure presented was demonstrated to be a successful, low‐cost and low‐maintenance procedure to obtain exoelectrogenic activity and had performances comparable with other more costly and complex inoculation procedures. The Sed‐MFC does not require a potentiostat, external aeration, stirring, membranes or an enriched inoculum in the exoelectrogenic biomass. © 2013 Society of Chemical Industry
A novel two‐species whole‐cell immobilization system composed of marine‐derived fungi and its application in wastewater treatment
Authors: Chen Hui‐Ying , Guan Yi‐Xin , Yao Shan‐Jing
Published: October 2013

BACKGROUND

Mycelia pellet has been exploited as a biological carrier for whole‐cell immobilization due to its unique structural characteristics. An innovative two‐species whole‐cell immobilization system was developed initially, which was achieved simply by inoculating the marine‐derived fungus Pestalotiopsis sp. J63 spores into culture medium containing another fungus Penicillium janthinellum P1 pre‐grown mycelia pellets for 2 days.

RESULTS

The resulting co‐immobilization system exhibited stronger biocatalytic activity, broader spectrum of substrates and remained more stable in media when subjected to hostile environment than free mycelia. In order to examine the potential function and prospects of this co‐immobilization system, the treatment of paper mill effluent was applied as a practical example. Numerous insoluble fine fibers in the wastewater were successfully and rapidly biodegraded and removed using this novel co‐immobilization system.

CONCLUSION

Overall, the present study offers a simple and reproducible way to architect a two‐species whole‐cell immobilization system, which is highly promising for biochemical and industrial processes. © 2013 Society of Chemical Industry