bluuebunny/crossref_metadata_2025 huggingface dataset:
A novel calibration approach of MODIS AOD data to predict PM2.5 concentrations
Authors: Lee H. J. , Liu Y. , Coull B. A. , Schwartz J. , Koutrakis P.
Published: March 2011

Abstract. Epidemiological studies investigating the human health effects of PM2.5 are susceptible to exposure measurement errors, a form of bias in exposure estimates, since they rely on data from a limited number of PM2.5 monitors within their study area. Satellite data can be used to expand spatial coverage, potentially enhancing our ability to estimate location- or subject-specific exposures to PM2.5, but some have reported poor predictive power. A new methodology was developed to calibrate aerosol optical depth (AOD) data obtained from the Moderate Resolution Imaging Spectroradiometer (MODIS). Subsequently, this method was used to predict ground daily PM2.5 concentrations in the New England region. 2003 MODIS AOD data corresponding to the New England region were retrieved, and PM2.5 concentrations measured at 26 US Environmental Protection Agency (EPA) PM2.5 monitoring sites were used to calibrate the AOD data. A mixed effects model which allows day-to-day variability in daily PM2.5-AOD relationships was used to predict location-specific PM2.5 levels. PM2.5 concentrations measured at the monitoring sites were compared to those predicted for the corresponding grid cells. Both cross-sectional and longitudinal comparisons between the observed and predicted concentrations suggested that the proposed new calibration approach renders MODIS AOD data a potentially useful predictor of PM2.5 concentrations. Furthermore, the estimated PM2.5 levels within the study domain were examined in relation to air pollution sources. Our approach made it possible to investigate the spatial patterns of PM2.5 concentrations within the study domain.
Long-range transport of terrain-induced turbulence from high-resolution numerical simulations
Authors: Katurji M. , Zhong S. , Zawar-Reza P.
Published: March 2011

Abstract. Over complex terrain, an important question is how various topographic features may generate or alter wind turbulence and how far the influence can be extended downstream. Current measurement technology limits the capability in providing a long-range snapshot of turbulence as atmospheric eddies travel over terrain, interact with each other, change their productive and dissipative properties, and are then observed tens of kilometers downstream of their source.In this study, we investigate through high-resolutionnumerical simulations the atmospheric transport of terrain-generated turbulence in an atmosphere that is neutrally stratified. The simulations are two-dimensional with an isotropic spatial resolution of 15 m and run to a quasi-steady state. They are designed in such a way to allow an examination of the effects of a bell-shaped experimental hill with varying height and aspect ratio on turbulence properties generated by another hill 20 km upstream. Averaged fields of the turbulent kinetic energy (TKE) implythat terrain could have a large influence on velocity perturbations at least 30 H (H is the terrain height) upstream and downstream of the terrain, with the largest effect happening in the area of the largest pressure perturbations. The results also show that downstream of the terrain the TKE fields are sensitive to the terrain's aspect ratio with larger enhancement in turbulence by higher aspect ratio, while upstream there is a suppression of turbulence that does not appear to be sensitive to the terrain aspect ratio. Instantaneous vorticity fields shows very detailed flow structures that resemble a multitude of eddy scales dynamically interacting while shearing oppositely paired vortices. The knowledge of the turbulence production and modifications by topography from these high-resolutionsimulationscan be helpful in understanding long-range terrain-induced turbulence and improving turbulence parameterizations used in lower resolution weather prediction models.
Uncertainty in the relationship between climate forcing and hydrological response in UK catchments
Authors: Arnell N. W.
Published: March 2011

Abstract. This paper assesses the relationship between amount of climate forcing – as indexed by global mean temperature change – and hydrological response in a sample of UK catchments. It constructs climate scenarios representing different changes in global mean temperature from an ensemble of 21 climate models assessed in the IPCC AR4. The results show a considerable range in impact between the 21 climate models, with – for example – change in summer runoff at a 2 °C increase in global mean temperature varying between −40% and +20%. There is evidence of clustering in the results, particularly in projected changes in summer runoff and indicators of low flows, implying that the ensemble mean is not an appropriate generalised indicator of impact, and that the standard deviation of responses does not adequately characterise uncertainty. The uncertainty in hydrological impact is therefore best characterised by considering the shape of the distribution of responses across multiple climate scenarios. For some climate model patterns, and some catchments, there is also evidence that linear climate change forcings produce non-linear hydrological impacts. For most variables and catchments, the effects of climate change are apparent above the effects of natural multi-decadal variability with an increase in global mean temperature above 1 °C, but there are differences between catchments. Based on the scenarios represented in the ensemble, the effect of climate change in northern upland catchments will be seen soonest in indicators of high flows, but in southern catchments effects will be apparent soonest in measures of summer and low flows. The uncertainty in response between different climate model patterns is considerably greater than the range due to uncertainty in hydrological model parameterisation.
Hydrological real-time modelling in the Zambezi river basin using satellite-based soil moisture and rainfall data
Authors: Meier P. , Frömelt A. , Kinzelbach W.
Published: March 2011

Abstract. Reliable real-time forecasts of the discharge can provide valuable information for the management of a river basin system. For the management of ecological releases even discharge forecasts with moderate accuracy can be beneficial. Sequential data assimilation using the Ensemble Kalman Filter provides a tool that is both efficient and robust for a real-time modelling framework. One key parameter in a hydrological system is the soil moisture, which recently can be characterized by satellite based measurements. A forecasting framework for the prediction of discharges is developed and applied to three different sub-basins of the Zambezi River Basin. The model is solely based on remote sensing data providing soil moisture and rainfall estimates. The soil moisture product used is based on the back-scattering intensity of a radar signal measured by a radar scatterometer. These soil moisture data correlate well with the measured discharge of the corresponding watershed if the data are shifted by a time lag which is dependent on the size and the dominant runoff process in the catchment. This time lag is the basis for the applicability of the soil moisture data for hydrological forecasts. The conceptual model developed is based on two storage compartments. The processes modeled include evaporation losses, infiltration and percolation. The application of this model in a real-time modelling framework yields good results in watersheds where soil storage is an important factor. The lead time of the forecast is dependent on the size and the retention capacity of the watershed. For the largest watershed a forecast over 40 days can be provided. However, the quality of the forecast increases significantly with decreasing prediction time. In a watershed with little soil storage and a quick response to rainfall events, the performance is relatively poor and the lead time is as short as 10 days only.
First evidence of accumulation of mega boulders on the Mediterranean rocky coast of Provence (southern France)
Authors: Vella C. , Demory F. , Canut V. , Dussouillez P. , Fleury T. J.
Published: March 2011

Abstract. An accumulation of boulders was recently discovered along the rocky coast of the Gulf of Fos located in Provence, in an area exposed to a south-westerly wave regime. The coast around this locality forms the western extremity of the calcareous Nerthe range between Marseille and the Rhône Delta. Several mega blocks are scattered to a distance of 30 m behind the coast line. The largest block (33.5 tonnes) has been transported about 39 m inland, up to about 2 m a.s.l. On the Mediterranean coast, the origin of such blocks is often attributed to tsunami-generated waves, but in the case examined here, although the origin is unclear, the differences in surface state between boulders indicates several events generated by south-westerly storms. Radiocarbon dating on several different shells collected from seven different boulders yields a wide dispersion of ages ranging from 4000 BP to the Modern Period. The differences in surface appearance, as well as the differences of fauna conservation and surface coloration, in some cases in a very fresh state, along with the dispersion of radiocarbon ages, suggest that historic storm events have affected these megablocks.
Cancer Research: Nanomaterials: Applications in Cancer Imaging and Therapy (Adv. Mater. 12/2011)
Authors: Barreto José A. , O’Malley William , Kubeil Manja , Graham Bim , Stephan Holger , Spiccia Leone
Published: March 2011

The application of nanomaterials (NMs) in biomedicine is increasing rapidly and offers excellent prospects for the development of new non‐invasive strategies for the diagnosis and treatment of cancer. In this review, we provide a brief description of cancer pathology and the characteristics that are important for tumor‐targeted NM design, followed by an overview of the different types of NMs explored to date, covering synthetic aspects and approaches explored for their application in unimodal and multimodal imaging, diagnosis and therapy. Significant synthetic advances now allow for the preparation of NMs with highly controlled geometry, surface charge, physicochemical properties, and the decoration of their surfaces with polymers and bioactive molecules in order to improve biocompatibility and to achieve active targeting. This is stimulating the development of a diverse range of nanometer‐sized objects that can recognize cancer tissue, enabling visualization of tumors, delivery of anti‐cancer drugs and/or the destruction of tumors by different therapeutic techniques.
Social network analysis in the study of nonhuman primates: A historical perspective
Authors: Brent Lauren J.N. , Lehmann Julia , Ramos‐Fernández Gabriel
Published: March 2011

Advances over the last 15 years have made social network analysis (SNA) a powerful tool for the study of nonhuman primate social behavior. Although many SNA‐based techniques have been only very recently adopted in primatological research, others have been commonly used by primatologists for decades. The roots of SNA also stem from some of the same conceptual frameworks as the majority of nonhuman primate behavioral research. The rapid development of SNA in recent years has led to questions within the primatological community of where and how SNA fits within this field. We aim to address these questions by providing an overview of the historical relationship between SNA and the study of nonhuman primates. We begin with a brief history of the development of SNA, followed by a detailed description of the network‐based visualization techniques, analytical methods and conceptual frameworks which have been employed by primatologists since as early as the 1960s. We also introduce some of the latest advances to SNA, thereby demonstrating that this approach contains novel tools for the study of nonhuman primate social behavior which may be used to shed light on questions that cannot be addressed fully using more conventional methods. Am. J. Primatol. 73:720–730, 2011. © 2011 Wiley‐Liss, Inc.
Alternative routes to the leader male role in a multi‐level society: follower vs. solitary male strategies and outcomes in hamadryas baboons
Authors: Pines Mathew , Saunders Julian , Swedell Larissa
Published: March 2011

The nested one‐male units (OMUs) of the hamadryas baboon are part of a complex social system in which “leader” males achieve near exclusive mating access by forcibly herding females into permanent consortships. Within this multi‐level social system (troops, bands, clans and OMUs) are two types of prereproductive males—the follower and solitary male—whose different trajectories converge on the leader role. Here we compare OMU formation strategies of followers, who associate with a particular OMU and may have social access to females, with those of solitary males, who move freely within the band and do not associate regularly with OMUs. Data were derived from 42 OMU formations (16 by followers and 26 by solitary males) occurring over 8 years in a hamadryas baboon band at the Filoha site in Ethiopia. “Initial units” (IUs) with sexually immature females (IU strategy) were formed by 44% of followers and 46% of solitary males. The remaining followers took over mature females when their leader was deposed (challenge strategy) or disappeared (opportunistic strategy), or via a seemingly peaceful transfer (inheritance strategy). Solitary males took over mature females from other clans and bands, but mainly from old, injured or vanished leaders within their clan (via both the challenge and opportunistic strategies). Former followers of an OMU were more successful at taking over females from those OMUs than any other category of male. Despite this advantage enjoyed by ex‐follower leaders, ex‐solitary leaders were equally capable of increasing their OMU size at a comparable rate in their first 2 years as a leader. These results demonstrate the potential for males to employ both multiple roles (follower vs. solitary male) and multiple routes (IU, inheritance, challenge, opportunistic) to acquire females and become a leader male in a mating system characterized by female defense polygyny in a competitive arena. Am. J. Primatol. 73:679–691, 2011. © 2011 Wiley‐Liss, Inc.
UV‐ and thermally triggered ring‐opening metathesis polymerization for the spatially resolved functionalization of polymeric monolithic devices
Authors: Ernst Claudia , Elsner Christian , Prager Andrea , Scheibitz Bettina , Buchmeiser Michael R.
Published: March 2011

Porous polymeric monolithic supports were prepared via electron beam‐triggered free radical polymerization using a mixture of ethyl methacrylate and trimethylolpropane triacrylate in 2‐propanol, 1‐dodecanol and toluene. Bicyclo[2.2.1]hept‐5‐en‐2‐ylmethyl acrylate (1) was grafted onto these monolithic supports in a spatially resolved way with the aid of masks using both electron beam‐ (EB) and UV‐triggered free radical polymerization. The thus immobilized norborn‐2‐ene‐containing graft polymers were further treated with the 2nd‐generation Grubbs initiator, i.e., RuCl2(PCy3)(IMesH2)(CHPh) (4) (IMesH2 = 1,3‐dimesitylimidazolin‐2‐ylidene), and then reacted with bicyclo[2.2.1]hept‐5‐en‐2‐ylmethyl pyrene‐1‐carboxylate (2). Alternatively, monoliths completely grafted with poly‐1 were surface grafted with 2 in a spatially resolved way in the presence of a latent, UV‐triggerable precatalyst, i.e., [Ru(IMesH2)(CF3COO)(t‐BuCN)4+ CF3COO−] (5). Finally, to demonstrate the utility of this chemistry, a 2nd‐generation Grubbs initiator‐based approach was used to prepare a trypsin‐functionalized monolith‐containing chip device that allowed for the online digestion of N‐α‐benzoyl‐L‐argininethylester hydrochloride. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Preparation, thermo‐optic property and transmission loss of chiral azobenzene polyurethane
Authors: Liu Jinhua , Qiu Fengxian , Cao Guorong , Shen Qiang , Cao Zhijuan , Yang Dongya
Published: March 2011

A novel chiral azobenzene polyurethane (CAPU) was prepared from chromophore, chiral reagent L(−)‐tartaric acid and toluene diisocyanate (TDI). The chemical structure and the thermal property were characterized by UV‐Vis spectrum, FT‐IR, 1H NMR, circular dichroism (CD) spectrum, differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA). DSC and TGA experiments showed that the glass transition temperature (Tg) and the decomposition temperature (Td) at 5% mass loss were 110°C and 199°C, respectively. The refractive index (n) and thermo‐optic coefficient (dn/dT) of the CAPU were measured at 650 nm wavelength and different temperature by attenuated total reflection (ATR) technique. By using CCD digital imaging devices, transmission loss of CAPU was measured and the value is 0.565dB/cm. The results will provide the foundation for many potential applications such as digital thermo‐optic switch materials and other fields in the future. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Polystyrene latex synthesized in presence of ultrasonic initiation
Authors: Bahattab Mohammed A.
Published: March 2011

The low water solubility of styrene (St) monomer increase the need for a good initiator system to speed up the emulsion polymerization and remove unreacted monomers. Polymerization of styrene monomer in water was performed at 30, 50, and 70°C under ultrasonic irradiation using sodium dodecyl sulfate as surfactant and ammonium persulfate as initiator. Ultrasonic energy was used as a tool to speed up the polymerization. Combining ultrasonic and ammonium persulfate led to a higher conversion and higher rate of polymerization. Ultrasonic energy has an effect on the particle size distribution. The particle size distribution increases with an increase in the monomer conversion of styrene for ultrasonic polymerization, whereas the particle size distribution did not change with an increase in the monomer conversion compared with the conventional thermal polymerization results. Higher molecular weights were obtained under ultrasonic irradiation. FE‐SEM and TEM pictures show different morphology with changing temperature polymerization. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Developmental Changes in Lectin‐Binding Patterns of Three Nasal Sensory Epithelia in Xenopus laevis
Authors: Endo Daisuke , Yamamoto Yoshio , Nakamuta Nobuaki , Taniguchi Kazuyuki
Published: March 2011

The nasal cavity of adult Xenopus laevis (X. laevis) is composed of a series of three compartments: principal, middle, and inferior chambers. The principal chamber is lined with olfactory epithelium (OE), middle chamber with middle chamber epithelium (MCE), and inferior chamber with vomeronasal epithelium (VNE). In the present study, we examined developmental changes of lectin‐binding patterns of the OE, MCE, and VNE by the use of four biotinylated lectins; DSL, DBA, PNA, and UEA‐I. From Stage 59, just after the beginning of metamorphosis, the stainings of the free border for DBA and UEA‐I were decreased in the OE and MCE, respectively, but the stainings of secretory granules (SGs) in the OE became intense. From Stage 63, sensory cells positive for DSL were increased in these three epithelia, and positive stainings for UEA‐I and DBA increased in the SGs and Jacobson's glands (JGs), respectively. In addition, from 3 months after the end of metamorphosis, the stainings of sensory cells for PNA, DBA, and DSL changed in the OE, MCE, and VNE, respectively, and those of the SGs, Bowman's glands, and JGs also changed for several lectins. The present results showed that glycoconjugates expressed in three epithelia and their associated glands changed during and after the end of metamorphosis. These findings may indicate that the functional maturation of each epithelium depends not only on the maturation of sensory cells, but also on the maturation of the SGs in supporting cells of the OE and their associated glands after the end of metamorphosis. Anat Rec, 2011. © 2011 Wiley‐Liss, Inc.
Sp1 Upregulates Survivin Expression in Adenocarcinoma of Lung Cell Line A549
Authors: Chen Yuqing , Wang Xiaojing , Li Wei , Zhang Hailong , Zhao Chengling , Li Yan , Wang Zhenhuan , Chen Changjie
Published: March 2011

Survivin has been implicated in tumor genesis, progression, and resistance to anticancer agents. However, the precise regulatory mechanism for survivin expression is not thoroughly defined. In this study, we showed that Sp1 was co‐overexpressed with survivin in adenocarcinoma of lung cells A549, but not in differentiated human bronchial epithelial cells 4F0439 or small airway epithelial cells 3F1584. Subsequently, transfection experiments demonstrated that the inhibition of Sp1 signaling suppressed survivin expression in A549 cells, whereas Sp1 overexpression increased the level of survivin protein as well as its mRNA. We also found that Sp1 could decrease capase‐9 activity, which is shown to be suppressed by survivin during apoptosis inhibition. Finally, Luciferase activity and ChIP assays revealed that Sp1 activated survivin promoter by direct interaction with it. Taken together, our data suggest Sp1 plays a potent role in the upregulation of survivin expression in lung cancer cells at the transcriptional level. Anat Rec, 2011. © 2011 Wiley‐Liss, Inc.
Electron Density of Two Bioactive Oligocyclic Indole and Oxindole Derivatives Obtained from Low‐Order X‐Ray Data and Invariom Application
Authors: Weber Manuela , Grabowsky Simon , Hazra Abhijit , Naskar Subhendu , Banerjee Sukdeb , Mondal Nirup B. , Luger Peter
Published: March 2011

For two indole and oxindole bioactive molecules, low‐order room‐temperature X‐ray data were used to generate aspherical electron density (ED) distributions by application of the invariom formalism. An analysis of the ED using the quantum theory of atoms in molecules (QTAIM) was carried out, which allowed for quantitatively examining bond orders and charge separations in various parts of the molecules. The inspection of electrostatic potentials (ESPs) and Hirshfeld surfaces provided additional information on the intermolecular interactions. Thus, reactive regions of the molecules could be identified, covalent and electrostatic contributions to interactions could be visualized, and the forces causing the crystal packing scheme could be rationalized. As the used invariom formalism needs no extra experimental effort compared to routine X‐ray analysis, its wide application is recommended because it delivers information far beyond the normally obtained steric properties. In this way, complementary contributions to drug design can be given as is demonstrated for indoles in this study, which are involved in the metabolism of plants and animals as well as in cancer therapy.
An Approach to 1,3,4‐Dioxaphospholane Complexes through an Acid‐Induced Ring Expansion of an Oxaphosphirane Complex: The Problem of Construction and Deconstruction of O,P‐Heterocycles
Authors: Pérez Janaina Marinas , Helten Holger , Schnakenburg Gregor , Streubel Rainer
Published: March 2011

Treatment of oxaphosphirane complex 1, triflic acid (TfOH), and various aldehydes yielded 1,3,4‐dioxaphospholane complexes 5a,b–7a,b after deprotonation with NEt3. In addition to NMR spectroscopy, IR spectroscopy, and MS data, the X‐ray structures of complexes 5a and 7a were determined. 31P NMR spectroscopic monitoring and DFT calculations provided insight into the reaction course and revealed the transient TfOH 1,3,4‐dioxaphospholanium association complex TfOH‐5a,b and/or TfOH‐5a,b′ as key reactive intermediates. Furthermore, it was observed that the five‐membered ring system was cleaved upon warming and yielded side‐on (E,Z)‐methylenephosphonium complexes 8a,b if deprotonation did not occur at low temperature. Overall, a novel temperature‐ and acid‐dependent construction and deconstruction process of the 1,3,4‐dioxaphospholane ring system is described.
Static magnetic field sensitivity of endothelial cells
Authors: Martino Carlos F.
Published: March 2011

In this manuscript, data demonstrating the magnetic sensitivity of human umbilical vein endothelial cells (HUVECs) is presented. The effects of low level fields (LLF; 0.2–1 µT), 30 and 120 µT magnetic fields on the proliferation of endothelial cells were investigated. Primary HUVECs were cultured and exposed to the distinct magnetic conditions in the same incubator. Although cell numbers were slightly affected between 30 and 120 µT magnetic fields, reducing the magnetic field to low levels clearly inhibited proliferation. The rationale of introducing LLF is to elucidate a possible mechanism of interaction. Small differences of 30 µT reduce endothelial cell numbers significantly. The addition of free radical scavenger superoxide dismutase suppressed the enhanced proliferation caused by 120 µT static magnetic fields. It is proposed that the static magnetic field interacts with endothelial cells via a free radical mechanism. Bioelectromagnetics 32:506–508, 2011. © 2011 Wiley‐Liss, Inc.
Studying the drift of in line pH measurements in cell culture
Authors: Saucedo V. , Wolk B. , Arroyo A. , Feng C. D.
Published: March 2011

The culture of Chinese hamster ovary (CHO) cells to produce monoclonal antibodies (MAb) requires accurate measurement and control of pH. Unwanted pH drifts in cell culture can adversely affect process performance, product quality, and product yield. To measure and control pH throughout the length of a culture, most cell culture processes use traditional glass pH probes. Several variables can affect the design and performance of glass pH electrodes and lead to drift in the measurement. Understanding these variables and their effects on pH performance can lead to design improvements and potentially reduce the drift. In this study, a set of Rosemount Analytical glass pH probes was investigated in cell culture operations. Electrochemical properties of the probes were monitored throughout the experiments. Experimental results show that the glass membrane potential experiences the biggest change during cell culture operations. Changes in the reference electrode potential are small compared with the changes in glass membrane potential. The glass membranes are affected by the steam sterilization process and this is the main cause for drift in the probe sensing signal during cell culture operations. Steam sterilization can cause the potential of glass membranes to change by up to 15 mV (∼ 0.25 pH units). This change in membrane potential can be observed as an undesirable pH drift in bioreactors. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011
Development and implementation of a perfusion‐based high cell density cell banking process
Authors: Tao Yiwen , Shih Jennifer , Sinacore Marty , Ryll Thomas , Yusuf‐Makagiansar Helena
Published: March 2011

A perfusion‐based high cell density (HD) cell banking process has been developed that offers substantial advantages in time savings and simplification of upstream unit operations. HD cell banking provides the means to reduce the time required for culture inoculum expansion and scale‐up by eliminating the need for multiple small to intermediate scale shake flask‐based operations saving up to 9 days of operation during large‐scale inoculum expansion. HD perfusion cultures were developed and optimized in a disposable Wave bioreactor system. Through optimization of perfusion rate, rocking speed and aeration rate, the perfusion system supported peak cell densities of >20 × 106 cells/mL while maintaining high cell viability (≥ 90%). The cells were frozen at HD (90–100 × 106 viable cells/mL) in 5‐mL CryoTube vials. HD cell banks were demonstrated to enable direct inoculation of culture into a Wave bioreactor in the inoculum expansion train thus eliminating the need for intermediate shake flask expansion unit operations. The simplicity of the disposable perfusion system and high quality of the cell banks resulted in the successful implementation in a 2000 L scale manufacturing facility. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011
Skeletal myotube integration with planar microelectrode arrays in vitro for spatially selective recording and stimulation: A comparison of neuronal and myotube extracellular action potentials
Authors: Langhammer Christopher G. , Kutzing Melinda K. , Luo Vincent , Zahn Jeffrey D. , Firestein Bonnie L.
Published: March 2011

Microelectrode array (MEA) technology holds tremendous potential in the fields of biodetection, lab‐on‐a‐chip applications, and tissue engineering by facilitating noninvasive electrical interaction with cells in vitro. To date, significant efforts at integrating the cellular component with this detection technology have worked exclusively with neurons or cardiac myocytes. We investigate the feasibility of using MEAs to record from skeletal myotubes derived from primary myoblasts as a way of introducing a third electrogenic cell type and expanding the potential end applications for MEA‐based biosensors. We find that the extracellular action potentials (EAPs) produced by spontaneously contractile myotubes have similar amplitudes to neuronal EAPs. It is possible to classify myotube EAPs by biological signal source using a shape‐based spike sorting process similar to that used to analyze neural spike trains. Successful spike‐sorting is indicated by a low within‐unit variability of myotube EAPs. Additionally, myotube activity can cause simultaneous activation of multiple electrodes, in a similar fashion to the activation of electrodes by networks of neurons. The existence of multiple electrode activation patterns indicates the presence of several large, independent myotubes. The ability to identify these patterns suggests that MEAs may provide an electrophysiological basis for examining the process by which myotube independence is maintained despite rapid myoblast fusion during differentiation. Finally, it is possible to use the underlying electrodes to selectively stimulate individual myotubes without stimulating others nearby. Potential uses of skeletal myotubes grown on MEA substrates include lab‐on‐a‐chip applications, tissue engineering, co‐cultures with motor neurons, and neural interfaces. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011
Hydrolysis of polyethyleneterephthalate by p‐nitrobenzylesterase from Bacillus subtilis
Authors: Ribitsch Doris , Heumann Sonja , Trotscha Eva , Herrero Acero Enrique , Greimel Katrin , Leber Regina , Birner‐Gruenberger Ruth , Deller Sigrid , Eiteljoerg Inge , Remler Peter , Weber Thomas , Siegert Petra , Maurer Karl‐Heinz , Donelli Ilaria , Freddi Giuliano , Schwab Helmut , Guebitz Georg M.
Published: March 2011

From a screening on agar plates with bis(benzoyloxyethyl) terephthalate (3PET), a Bacillus subtilis p‐nitrobenzylesterase (BsEstB) was isolated and demonstrated to hydrolyze polyethyleneterephthalate (PET). PET‐hydrolase active strains produced clearing zones and led to the release of the 3PET hydrolysis products terephthalic acid (TA), benzoic acid (BA), 2‐hydroxyethyl benzoate (HEB), and mono‐(2‐hydroxyethyl) terephthalate (MHET) in 3PET supplemented liquid cultures. The 3PET‐hydrolase was isolated from non‐denaturating polyacrylamide gels using fluorescein diacetate (FDA) and identified as BsEstB by LC‐MS/MS analysis. BsEstB was expressed in Escherichia coli with C‐terminally fused StrepTag II for purification. The tagged enzyme had a molecular mass of 55.2 kDa and a specific activity of 77 U/mg on p‐nitrophenyl acetate and 108 U/mg on p‐nitrophenyl butyrate. BsEstB was most active at 40°C and pH 7.0 and stable for several days at pH 7.0 and 37°C while the half‐life times decreased to 3 days at 40°C and only 6 h at 45°C. From 3PET, BsEstB released TA, MHET, and BA, but neither bis(2‐hydroxyethyl) terephthalate (BHET) nor hydroxyethylbenzoate (HEB). The kcat values decreased with increasing complexity of the substrate from 6 and 8 (s−1) for p‐nitrophenyl‐acetate (4NPA) and p‐nitrophenyl‐butyrate (4NPB), respectively, to 0.14 (s−1) for bis(2‐hydroxyethyl) terephthalate (BHET). The enzyme hydrolyzed PET films releasing TA and MHET with a concomitant decrease of the water‐contact angle (WCA) from 68.2° ± 1.7° to 62.6° ± 1.1° due to formation of novel hydroxyl and carboxyl groups. These data correlated with a fluorescence emission intensity increase seen for the enzyme treated sample after derivatization with 2‐(bromomethyl)naphthalene. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011
Protein extraction by Winsor‐III microemulsion systems
Authors: Gomez del Rio Javier A. , Hayes Douglas G.
Published: March 2011

Proteins (bovine serum albumin (BSA), α‐chymotrypsin, cytochrome c, and lysozyme) were extracted from 0.5 to 2.0 g L−1 aqueous solution by adding an equal volume of isooctane solution that contained a surfactant mixture (Aerosol‐OT, or AOT, and a 1,3‐dioxolane (or cyclic ketal) alkyl ethoxylate, CK‐2,13‐E5.6), producing a three‐phase (Winsor‐III) microemulsion with a middle, bicontinuous microemulsion, phase highly concentrated in protein (5–13 g L−1) and small in volume (12–20% of entire volume). Greater than 90% forward extraction was achieved within a few minutes. Robust W‐III microemulsion systems were formulated at 40°C, or at 25°C by including a surfactant with shorter ethoxylate length, CK‐2,13‐E3, or 1.5% NaCl (aq). Successful forward extraction correlated with high partitioning of AOT in the middle phase (>95%). The driving force for forward extraction was mainly electrostatic attractions imposed by the anionic surfactant AOT, with the exception of BSA at high ionic strength, which interacted via hydrophobic interactions. Through use of aqueous stripping solutions of high ionic strength (5.0 wt %) and/or pH 12.0 (to negate the electrostatic attractive driving force), cytochrome c and α‐chymotrypsin were back extracted from the middle phase at >75% by mass, with the specific activity of recovered α‐chymotrypsin being >90% of its original value. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011
Enhancing hypericin production of Hypericum perforatum cell suspension culture by ozone exposure
Authors: Xu Maojun , Yang Bin , Dong Jufang , Lu Dan , Jin Haihong , Sun Lina , Zhu Yun , Xu Xiangbin
Published: March 2011

Accumulation of secondary metabolites is one of the common reactions of plants to ozone exposure in nature. To investigate the effect of ozone on the production of desired compounds of plant cell cultures, we assayed hypericin production of Hypericum perforatum suspension cell cultures treated with different doses of ozone at different culture phases. The results show that hypericin contents of the cells treated with 60 to 180 nL L−1 ozone are significantly higher than those of the control, showing that ozone exposure may stimulate hypericin synthesis. Hypericin production of the cells treated with ozone at exponential phase is higher than that of lag and stationary phase, which suggests that exponential phase cell cultures are more responsive to ozone exposure than lag and stationary phase cells. The highest hypericin production is obtained by the cells exposed to 90 nL L−1 ozone at late exponential phase for 3 h, being about fourfold of the control. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011
Noninvasive investigation of asymmetrically conjoined tripus twins with features of rachipagus, parapagus dicephalus, and cephalopagus
Authors: Lee A.W. , Farnquist B. , Islam O. , Mackenzie J. , Taylor S.A.M. , Pang S.C. , Reifel C.W.
Published: March 2011

A hypothetical mechanism for conjoined twinning postulated by Spencer ([2003] Developmental Malformations and Clinical Implications, Baltimore: Johns Hopkins University Press, p 1–476) suggests that, after separation, monovular twins fuse in one of eight predictable homologous sites. The tripus fetal specimen under study embodies characteristics of three types therefore preventing it from classification into a simple variant of any one of the eight twin types described by Spencer. The aim of this study was to reveal internal structural anomalies of the fetal specimen by using magnetic resonance imaging and computerized tomography. Dorsally appended to the primary twin is a secondary head mass (brain tissue and ocular globe) and two spinal columns converging at T4/T5, suggesting rachipagus twinning. The ventral orientation of the secondary twin's (right lateral) lower limb suggests parapagus twinning. The caudal divergence of the spinal columns and the presence of a secondary hemipelvis, separate from the primary pelvis, suggest cephalopagus twinning. Measurements of the long bones indicate a gestational age of ∼20–23 weeks. Secondary malformations of the primary fetal body include anencephaly, cleft palate, renal agenesis, decreased left ventricular outflow, and a prematurely terminating descending aorta. This study demonstrates the possibility of using current imaging techniques to study very old, formalin‐preserved human material for documentation and scientific discussion without destroying the specimen, thus keeping it intact for posterity. Clin. Anat. 25:1023–1029, 2012. © 2012 Wiley Periodicals, Inc.
Why there are two rows of deep inferior epigastric artery perforators despite variability in the number of deep inferior epigastric artery trunks: An anatomical and embryological argument
Authors: Rozen Warren M. , Kapila Shivam , Donahoe Simon
Published: March 2011

The deep inferior epigastric artery (DIEA) distributes musculocutaneous perforators in a uniform pattern that comprises “medial row” versus “lateral row” perforators, with these two rows having anatomical and functional differences. This pattern of two perforator rows is distributed from the DIEA regardless of the number of major DIEA trunks, with there variably being one to four major trunks. As such, a single DIEA trunk will still distribute two perforator rows, as will four major DIEA trunks. What remains to be answered is how such an anatomical fact may come to be? The answer probably lies in the anatomy and embryology of the rectus abdominis muscle itself. With two muscle heads to each hemiabdominal rectus abdominis muscle present from early in its development, it is highly likely that each head of rectus abdominis muscle draws its own blood supply from its source DIEA pedicle, one “perforator row” for each head, regardless of DIEA branching pattern from which these rows are drawn, thus providing an embryological and anatomical basis for the observation of two uniform perforator rows. Clin. Anat. 24:786–788, 2011. © 2011 Wiley‐Liss, Inc.
Reactions of exo‐Substituted RSn93− Clusters with Pd: Endohedral Cluster Formation and Oxidative Insertion
Authors: Kocak F. Sanem , Zavalij Peter , Eichhorn Bryan
Published: March 2011

Pyridine/ethylenediamine solutions of [Sn9SnCy3]3− (1) react with [Pd(PPh3)4] to give new clusters [Pd@Sn9SnCy3]3− (2) and [Pd@Sn9PdSnCy3]3− (3), depending on stoichiometry. These compounds are formed sequentially and are the first transition metal derivates of exo‐substituted Zintl clusters. Oxidative insertion of a Pd atom into the Pd@Sn9SnCy3 bond of 2 to form 3 represents a new reaction type for Zintl cluster compounds. The conversion Sn94−→1→2→3 is a rare case in which charge and mass are conserved in a series of Zintl clusters. Complexes 1, 2, and 3 are all highly fluxional in solution. In all three clusters, the nine Sn vertices are in rapid exchange on the NMR timescale. In 1 and 2, the exo‐SnCy3 substituent also scrambles intramolecularly around the outside of the clusters. In 3, the SnCy3 group remains attached to the vertex Pd atom. The disparate reactions with the other RSn93− ions are discussed.
The Role of Surface and Subsurface Point Defects for Chemical Model Studies on TiO2: A First‐Principles Theoretical Study of Formaldehyde Bonding on Rutile TiO2(110)
Authors: Haubrich Jan , Kaxiras Efthimios , Friend Cynthia M.
Published: March 2011

We report a systematic investigation of the effects of different surface and subsurface point defects on the adsorption of formaldehyde on rutile TiO2(110) surfaces using density functional theory (DFT). All point defects investigated—including surface bridging oxygen vacancies, titanium interstitials, and subsurface oxygen vacancies—stabilize the adsorption significantly by up to 56 kJ mol−1 at a coverage of 0.1 monolayer (ML). The stabilization is due to a decrease of the coordination (covalent saturation) of the surface Ti adsorption sites adjacent to the defects, which leads to a stronger molecule–surface interaction. This change in the Ti is caused by the removal of a neighboring atom (oxygen vacancies) or substantial lattice relaxations induced by the subsurface defects. On the stoichiometric reference surface, the most stable adsorption geometry of formaldehyde is a tilted η2‐dioxymethylene (with an adsorption energy Eads=−125 kJ mol−1), in which a bond forms to a nearby bridging O atom and the carbonyl‐O atom in the formaldehyde binds to a Ti atom in the adjacent fivefold coordinated lattice site. The η1‐top configuration on five‐coordinate Ti4+ is much less favorable (Eads=−69 kJ mol−1). The largest stabilization is exerted by subsurface Ti interstitials between the first and second layers. These defects stabilize the η2‐dioxymethylene structure by nearly 40 kJ mol−1 to an adsorption energy of −164 kJ mol−1. Contrary to popular belief, adsorption in a bridging oxygen vacancy (Eads=−86 kJ mol−1) is much less favorable for formaldehyde compared to the η2‐ dioxymethylene structures. From these results we conclude that formaldehyde will bind in the η2‐dioxymethylene structure on the stoichiometric surface as well as in the presence of Ti interstitials and bridging oxygen vacancies. In the light of these substantial effects, we conclude that it is essential to include all the types of point defects present in typical, reduced rutile samples used for model studies, at realistic concentrations to obtain correct adsorption sites, structures, energetic, and chemi‐physical properties.
Protonation of Water Clusters Induced by Hydroperoxyl Radical Surface Adsorption
Authors: Torrent‐Sucarrat Miquel , Ruiz‐Lopez Manuel F. , Martins‐Costa Marilia , Francisco Joseph S. , Anglada Josep M.
Published: March 2011

We have investigated the HO2 adsorption and acid dissociation process on the surface of (H2O)20 and (H2O)21 clusters by using quantum‐chemistry calculations. Our results show that the radical forms a stable hydrogen‐bond complex on the cluster. The HO2 acid dissociation is more favorable in the case of the (H2O)21 cluster, for which the inner water molecule plays a crucial role. In fact, acid dissociation of HO2 is found to occur in two steps. The first step involves H2O autoionization in the cluster, and the second one involves the proton transfer from the HO2 radical to the hydroxide anion. The presence of the HO2 radicals on the surface of the cluster facilitates water autoionization in the cluster.
Air‐Stable n‐Type Organic Field‐Effect Transistors Based on Solution‐Processable, Electronegative Oligomers Containing Dicyanomethylene‐Substituted Cyclopenta[b]thiophene
Authors: Ie Yutaka , Nishida Kazufumi , Karakawa Makoto , Tada Hirokazu , Asano Atsushi , Saeki Akinori , Seki Shu , Aso Yoshio
Published: March 2011

Solution‐processable, electronegative, π‐conjugated systems containing dicyanomethylene‐substituted cyclopenta[b]thiophene were synthesized as potential active materials for air‐stable n‐type organic field‐effect transistors (OFETs). Electrochemical measurements revealed that these compounds exhibited electrochemical stability and that the lowest unoccupied molecular orbital (LUMO) had an energy level less than −4.0 eV. Flash‐photolysis time‐resolved microwave conductivity (FP‐TRMC) measurements were performed, and the value of intradomain electron mobility was determined to be as high as 0.1 cm2 V−1 s−1. The OFETs were fabricated by spin‐coating thin films of the compounds as an active layer. The electron mobility of the OFETs was 3.5×10−3 cm2 V−1 s−1 in vacuum. Furthermore, electron mobility of the same order of magnitude and stable characteristics were obtained under air‐exposed conditions. X‐ray diffraction measurements of the spin‐coated thin films revealed the difference of molecular arrangements depending on the inner conjugated units. Atomic force microscopy measurements of crystalline‐structured films exhibited the formation of grains. The accomplishment of air‐stability was attributed to the combined effect of the low‐lying LUMO energy level and the molecular arrangements in the solid state, avoiding both the quenching of electron carriers and the intrusion of oxygen and/or moisture.
Olefin Metathesis Featuring Ruthenium Indenylidene Complexes with a Sterically Demanding NHC Ligand
Authors: Urbina‐Blanco César A. , Leitgeb Anita , Slugovc Christian , Bantreil Xavier , Clavier Hervé , Slawin Alexandra M. Z. , Nolan Steven P.
Published: March 2011

The synthesis and characterization of two new ruthenium indenylidene complexes [RuCl2(SIPr)(Py)(Ind)] 6 and [RuCl2(SIPr)(3‐BrPy)(Ind)] 7 featuring the sterically demanding N‐heterocyclic carbene 1,3‐bis(2,6‐di isopropylphenyl)‐4,5‐dihydroimidazol‐2‐ylidene (SIPr) are reported. Remarkable activity was observed with these complexes in ring closing, enyne, and cross metathesis of olefins at low catalyst loadings. The performance of SIPr‐bearing complexes 6 and 7 as well as [RuCl2(SIPr)(PCy3)(Ind)] 5 in ring opening metathesis polymerization is also disclosed. This work highlights the enormous influence of the neutral “spectator” ligands on catalyst activity and stability.
The Influence of SO2 and NO2 Impurities on CO2 Gas Hydrate Formation and Stability
Authors: Beeskow‐Strauch Bettina , Schicks Judith M. , Spangenberg Erik , Erzinger Jörg
Published: March 2011

The sequestration of industrially emitted CO2 in gas hydrate reservoirs has been recently discussed as an option to reduce atmospheric greenhouse gas. This CO2 contains, despite much effort to clean it, traces of impurities such as SO2 and NO2. Here, we present results of a pilot study on CO2 hydrates contaminated with 1 % SO2 or 1 % NO2 and show the impact on hydrate formation and stability. Microscopic observations show similar hydrate formation rates, but an increase in hydrate stability in the presence of SO2. Laser Raman spectroscopy indicates a strong enrichment of SO2 in the liquid and hydrate phase and its incorporation in both large and small cages of the hydrate lattice. NO2 is not verifiable by laser Raman spectroscopy, only the presence of nitrate ions could be confirmed. Differential scanning calorimetry analyses show that hydrate stability and dissociation enthalpy of mixed CO2–SO2 hydrates increase, but that only negligible changes arise in the presence of NO2 impurities. X‐ray diffraction data reveal the formation of sI hydrate in all experiments. The conversion rates of ice+gas to hydrate increase in the presence of SO2, but decrease in the presence of NO2. After hydrate dissociation, SO2 and NO2 dissolved in water and form strong acids.
Versatile Phase Transfer of Gold Nanoparticles from Aqueous Media to Different Organic Media
Authors: Karg Matthias , Schelero Natascha , Oppel Claudia , Gradzielski Michael , Hellweg Thomas , von Klitzing Regine
Published: March 2011

A novel, simple, and very efficient method to prepare hydrophobically modified gold particles is presented. Gold nanoparticles of different sizes and polydispersities were prepared. The diameter of the gold particles ranges from 5 to 37 nm. All systems were prepared in aqueous solution stabilized by citrate and afterwards transferred into an organic phase by using amphiphilic alkylamine ligands with different alkyl chain lengths. The chain length was varied between 8 and 18 alkyl groups. Depending on the particle size and the alkylamine, different transfer efficiencies were obtained. In some cases, the phase transfer has a yield of about 100 %. After drying, the particles can be redispersed in different organic solvents. Characterization of the particles before and after transfer was performed by using UV/Vis spectroscopy, transmission electron microscopy (TEM), and small‐angle X‐ray scattering (SAXS) techniques. The effect of organic solvents with various refractive indices on the plasmon band position was investigated.