bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lipid‐Containing Polymer Vesicles with pH/Ca2+‐Ion‐Manipulated, Size‐Selective Permeability
Authors: Huang Wen‐Chia , Chiang Wen‐Hsuan , Lin Su‐Jen , Lan Yu‐Jen , Chen Hsin‐Lung , Chern Chorng‐Shyan , Chiu Hsin‐Cheng 
Published: March 2012

AbstractPolymeric vesicles attained from the self‐assembly of distearin (a diacylglycerol lipid)‐conjugated poly(acrylic acid) (PAAc) with various distearin contents in the aqueous phase show the capability of control over the vesicular‐wall permeability to hydrophilic solutes of varying sizes by a simple manipulation of the external pH. The pH sensitivity of the vesicle membranes in size‐selective permeability is largely dependent upon the lipid content of copolymer. By the addition of CaCl2 in aqueous vesicle suspensions, the pH‐evolved assembly structure and the membrane permeability can be immobilized with promoted resistance to further pH alteration, along with an additional counterion screening effect that reduces the pH required for the onset of polar solutes of certain sizes to pass through the membranes. Small‐angle X‐ray scattering (SAXS) measurements of the vesicle structure in the aqueous phase indicate that the pH‐regulated permeability to polar solutes is virtually governed by the extent of hydration and swelling of the vesicle membranes, and the lipid residues within each vesicle wall are packed into the ≈4–5 repeating lamellar islet structure surrounded by PAAc segments.
Microfabricated Biomaterials for Engineering 3D Tissues
Authors: Zorlutuna Pinar , Annabi Nasim , Camci‐Unal Gulden , Nikkhah Mehdi , Cha Jae Min , Nichol Jason W. , Manbachi Amir , Bae Hojae , Chen Shaochen , Khademhosseini Ali 
Published: March 2012

AbstractMimicking natural tissue structure is crucial for engineered tissues with intended applications ranging from regenerative medicine to biorobotics. Native tissues are highly organized at the microscale, thus making these natural characteristics an integral part of creating effective biomimetic tissue structures. There exists a growing appreciation that the incorporation of similar highly organized microscale structures in tissue engineering may yield a remedy for problems ranging from vascularization to cell function control/determination. In this review, we highlight the recent progress in the field of microscale tissue engineering and discuss the use of various biomaterials for generating engineered tissue structures with microscale features. In particular, we will discuss the use of microscale approaches to engineer the architecture of scaffolds, generate artificial vasculature, and control cellular orientation and differentiation. In addition, the emergence of microfabricated tissue units and the modular assembly to emulate hierarchical tissues will be discussed.
Core Scaffold‐Inspired Concise Synthesis of Chiral Spirooxindole‐Pyranopyrimidines with Broad‐Spectrum Anticancer Potency
Authors: Jiang Xianxing , Sun Yulong , Yao Jia , Cao Yiming , Kai Ming , He Ning , Zhang Xiaoyuan , Wang Yiqing , Wang Rui 
Published: March 2012

AbstractDue to the lack of tumor‐specific anticancer agents, the discovery and development of new types of highly selective anticancer agents is still a very urgent topic. Herein, we present our contribution to concise construction of novel chiral spirooxindole‐type pyranopyrimidines exhibiting a unique profile of biological activities. We have found that this new type of spiro alkaloid could inhibit the proliferation of various cancer cells in a preliminary biological evaluation. These findings suggested that spirooxindole‐type pyranopyrimidines, developed by an asymmetric Michael/cyclization strategy, can potentially serve as a new kind of anticancer candidate.
Enantioselective Synthesis of Highly Functionalized Trifluoromethyl‐Bearing Cyclopentenes: Asymmetric [3+2] Annulation of Morita–Baylis–Hillman Carbonates with Trifluoroethylidenemalonates Catalyzed by Multifunctional Thiourea‐Phosphines
Authors: Deng Hong‐Ping , Wei Yin , Shi Min 
Published: March 2012

AbstractOn the basis of the design and synthesis of multifunctional thiourea‐phosphines, a catalytic method for the asymmetric [3+2] annulation of Morita–Baylis–Hillman carbonates with trifluoroethylidenemalonates has been developed, affording highly functionalized trifluoromethyl‐bearing cyclopentenes in excellent yields, high diastereoselectivities and enantioselectivities under mild conditions.
Dental health in Northern Chile's Atacama oases: Evaluating the Middle Horizon (AD 500–1000) impact on local diet
Authors: Hubbe Mark , Torres‐Rouff Christina , Neves Walter Alves , King Laura M. , Da‐Gloria Pedro , Costa Maria Antonietta 
Published: March 2012

AbstractAs one of the few areas apt for horticulture in Northern Chile's arid landscape, the prehistory of the Atacama oases is deeply enmeshed with that of the inter‐regional networks that promoted societal development in the south central Andes. During the Middle Horizon (AD 500–1000), local populations experienced a cultural apex associated with a substantial increase in inter‐regional interaction, population density, and quantity and quality of mortuary assemblages. Here, we test if this cultural peak affected dietary practices equally among the distinct local groups of this period. We examine caries prevalence and the degree of occlusal wear in four series recovered from three cemeteries. Our results show a reduction in the prevalence of caries for males among an elite subsample from Solcor 3 and the later Coyo 3 cemeteries. Dental wear tends to increase over time with the Late Middle Horizon/Late Intermediate Period cemetery of Quitor 6 showing a higher average degree of wear. When considered in concert with archaeological information, we concluded that the Middle Horizon was marked by dietary variability wherein some populations were able to obtain better access to protein sources (e.g., camelid meat). Not all members of Atacameño society benefited from this, as we note that this dietary change only affected men. Our results suggest that the benefits brought to the San Pedro oases during the Middle Horizon were not equally distributed among local groups and that social status, relationship to the Tiwanaku polity, and interment in particular cemeteries affected dietary composition. Am J Phys Anthropol, 2012. © 2012 Wiley Periodicals, Inc.
Total Syntheses of the Elusive Welwitindolinones with Bicyclo[4.3.1] Cores
Authors: Huters Alexander D. , Styduhar Evan D. , Garg Neil K. 
Published: March 2012

AbstractThe welwitindolinones with bicyclo[4.3.1] cores are a class of natural products that have attracted tremendous interest from the synthetic community because of their fascinating structures and promising biological profiles. More than 15 research groups worldwide have reported progress toward these elusive natural products. This Minireview describes contemporary studies aimed at the total synthesis of these challenging targets, in addition to the two recently completed syntheses of welwitindolinones with bicyclo[4.3.1] cores reported by Rawal and Garg in 2011. Both of the completed efforts rely on C4C11 bond constructions to access the congested bicyclic framework of these elusive natural products.
Reaction of “Non‐Symmetrical” 1,2,4‐Trithiolanes with [(phosphane)Pt0(η2‐nbe)] Complexes
Authors: Weisheit Thomas , Kriltz Antje , Görls Helmar , Mlostoń Grzegorz , Imhof Wolfgang , Weigand Wolfgang 
Published: March 2012

AbstractTwo unsymmetrical 1,2,4‐trithiolanes (1d and 1e) were reacted with [Pt0(PPh3)2(η2‐nbe)] (6; nbe=norborn‐2‐ene) and [Pt0(dppn)(η2‐nbe)] (11; dppn=1,8‐bis(diphenylphosphanyl)naphthalene)), respectively. Their treatment with compound 6 resulted in the formation of six‐membered platinacycles of type 7, which selectively underwent fragmentation into dithiolato complexes and thiobenzophenone (4b). The isolation of the first stable C‐substituted member of this class of compounds (i.e., compound 7e) permitted kinetic studies of this process by using UV/Vis spectroscopy. These results, together with DFT calculations, allowed us to propose a mechanism for the reactions of compound 6 with 1,2,4‐trithiolanes. In contrast, similar treatment of compound 11 with compounds 1d and 1e at room temperature did not result in any reaction. Heating the appropriate samples to 110 °C led to the formation of dithiolato complexes and η2‐thioketone compounds, thus pointing to a thermally induced [3+2]‐cycloreversion of the heterocycles as an initial step of the reaction.
A stochastic multi‐period investment selection model to optimize strategic railway capacity planning
Authors: Lai Yung‐Cheng , Shih Mei‐Cheng 
Published: March 2012

SUMMARYNorth American Freight Railroads are approaching the limits of practical capacity because of substantial future demand. In this research, we develop a Stochastic Multi‐period Investment Selection Model (S‐MISM) to assist railroads best allocate their capital investments in the long‐term strategic capacity planning process. The novel optimization framework uses stochastic programming and Benders decomposition and provides a means to cope with unfulfilled demand and demand uncertainty in a long‐term multi‐period investment selection problem. S‐MISM can determine which portions of a rail network need to be upgraded with what kind of expansion options at each defined period in the planning horizon. Experimental results show that the inclusion of demand uncertainty results in a better and more robust capacity plan. Using this decision support tool will help railroads maximize their return from capacity expansion projects and minimize the risk in strategic capacity planning subject to demand uncertainty. Copyright © 2012 John Wiley & Sons, Ltd.
Genetic variants of organic cation transporter 1 (OCT1) and OCT2 significantly reduce lamivudine uptake
Authors: Choi Min‐Koo , Song Im‐Sook 
Published: March 2012

ABSTRACTThe study sought to investigate the effect of genetic variants of OCT1 (OCT1‐P283L and ‐P341L) and OCT2 (OCT2‐T199I, ‐T201M and ‐A270S), which were identified in a Korean population, on the transport of lamivudine in vitro and to compare the substrate dependent effects of OCT1 and OCT2 variants with 1‐methyl‐4‐phenylpyridinium (MPP+), tetraethyl ammonium (TEA), metformin and lamivudine as substrates for these transporters. When the transport kinetics of lamivudine uptake in oocytes overexpressing OCT1 and OCT2 wild‐type (WT) and variant proteins were measured, lamivudine uptake mediated by OCT1‐WT was saturable, and uptake was decreased in oocytes expressing OCT1‐P283L and ‐P341L variants compared with that in OCT1‐WT. The Clint of lamivudine in oocytes expressing OCT1‐P283L was decreased by 85.1% compared with OCT1‐WT, whereas it was decreased by 48.7% in oocytes expressing OCT1‐P341L. The Clint of lamivudine in oocytes expressing OCT2‐T199I, ‐T201M and ‐A270S was decreased by 86.2%, 88.9% and 73.6%, respectively, compared with OCT2‐WT. When comparing various substrates such as MPP+, TEA, metformin and lamivudine, the effects of the OCT1 genetic polymorphisms on their uptake were not identical. However, contrary to the case of OCT1, the uptake of MPP+, TEA, metformin and lamivudine in oocytes expressing OCT2‐T199I, ‐T201M and ‐A270S variants was decreased significantly compared with that in oocytes expressing OCT2‐WT. In conclusion, the effect of genetic variations of OCT1 and OCT2 on the uptake of MPP+, TEA, metformin and lamivudine was substrate‐dependent. Copyright © 2012 John Wiley & Sons, Ltd.
Fluorescence correlation spectroscopy
Authors: Ries Jonas , Schwille Petra 
Published: March 2012

AbstractFluorescence correlation spectroscopy (FCS) is a powerful technique to measure concentrations, mobilities, and interactions of fluorescent biomolecules. It can be applied to various biological systems such as simple homogeneous solutions, cells, artificial, or cellular membranes and whole organisms. Here, we introduce the basic principle of FCS, discuss its application to biological questions as well as its limitations and challenges, present an overview of novel technical developments to overcome those challenges, and conclude with speculations about the future applications of fluorescence fluctuation spectroscopy.
Macromolecular structure modeling from 3D EM using VolRover 2.0
Authors: Zhang Qin , Bettadapura Radhakrishna , Bajaj Chandrajit 
Published: March 2012

AbstractWe review tools for structure identification and model‐based refinement from three‐dimensional electron microscopy implemented in our in‐house software package, VOLROVER 2.0. For viral density maps with icosahedral symmetry, we segment the capsid, polymeric, and monomeric subunits using techniques based on automatic symmetry detection and multidomain fast marching. For large biomolecules without symmetry information, we again use our multidomain fast‐marching method with manual or fit‐based multiseeding to segment meaningful substructures. In either case, we subject the resulting segmented subunit to secondary structure detection when the EM resolution is sufficiently high, and rigid‐body structure fitting when the corresponding X‐ray structure is available. Secondary structure elements are identified by three techniques: our earlier volume‐based and boundary‐based skeletonization methods as well as a new method, currently in development, based on solving the grassfire flow equation. For rigid‐body fitting, we adapt our earlier fast Fourier‐based correlation scheme F2Dock. Our reported segmentation, secondary structure elements identification, and rigid‐body fitting techniques, implemented in VOLROVER 2.0 are applied to the PSB 2011 cryo‐EM modeling challenge data, and our results are briefly compared to similar results submitted from other research groups. The comparisons show that our techniques are equally capable of segmenting relatively accurate subunits from a viral or protein assembly, and that high segmentation quality leads in turn to higher‐quality results of secondary structure elements identification and correlation‐based rigid‐body fitting. © 2012 Wiley Periodicals, Inc. Biopolymers 97: 709–731, 2012.
Kinetic and Stoichiometric Characterisation of Streptavidin‐Binding Aptamers
Authors: Ruigrok Vincent J. B. , van Duijn Esther , Barendregt Arjan , Dyer Kevin , Tainer John A. , Stoltenburg Regina , Strehlitz Beate , Levisson Mark , Smidt Hauke , van der Oost John 
Published: March 2012

AbstractAptamers are oligonucleotide ligands that are selected for high‐affinity binding to molecular targets. Only limited knowledge relating to relations between structural and kinetic properties that define aptamer–target interactions is available. To this end, streptavidin‐binding aptamers were isolated and characterised by distinct analytical techniques. Binding kinetics of five broadly similar aptamers were determined by surface plasmon resonance (SPR); affinities ranged from 35–375 nM with large differences in association and dissociation rates. Native mass spectrometry showed that streptavidin can accommodate up to two aptamer units. In a 3D model of one aptamer, conserved regions are exposed, strongly suggesting that they directly interact with the biotin‐binding pockets of streptavidin. Mutational studies confirmed both conserved regions to be crucial for binding. An important result is the observation that the most abundant aptamer in our selections is not the tightest binder, emphasising the importance of having insight into the kinetics of complex formation. To find the tightest binder it might be better to perform fewer selection rounds and to focus on post‐selection characterisation, through the use of complementary approaches as described in this study.
Engagement in psychosocial treatment: Its relationship to outcome and care pathway progress for women in medium‐secure settings
Authors: Long Clive , Dolley Olga , Hollin Clive 
Published: March 2012

ABSTRACTBackgroundEngaging patients in treatment in secure settings is a major challenge. Engagement is associated with a shorter length of stay, whereas treatment non‐completion is associated with an increased risk of recidivism.AimsThe aims of this study were to assess differences between high and low treatment attendees in a women's medium secure unit and to compare progress over the course of their stay.MethodsSixty consecutive admissions to a women's medium secure unit were classified into high and low treatment attendee groups. The two groups were compared in terms of risk behaviours and psychometric measures of symptomatology, impulsivity and personality.ResultsHigh treatment attendees had a shortened length of stay, showed less disturbed behaviour and made more progress in terms of a reduction in symptoms overall and traumatic stress symptoms specifically. Low treatment attendees were more likely to have a diagnosis of schizophrenia/schizotypal illness than personality disorder, less likely to be impulsive and more likely to have scores indicative of severe disorder on the personality subscales of the Millon Clinical Multiaxial Inventory—III.ConclusionAttendance at groups in this medium security unit had clear advantages for patients and potential cost savings for services and the community, but we found a subgroup of women who found it difficult to attend. Given the small sample size, we advocate replication, but our findings suggest the following:Implications for practice

development of motivational interventions to help patients make a therapeutic alliance
more accurate assessment of treatment readiness, to avoid mistimed interventions that are counterproductive
more effective deployment of milieu therapeutic approaches to stabilise behaviour at an early stage of hospitalisation
abandonment of a ‘one size fits all’ approach to groups for mixed patient populations. More ‘customised’ approaches would allow more appropriate ‘pacing’ of treatment and adaptations of interventions according to need during the treatment course. Copyright © 2012 John Wiley & Sons, Ltd.
Novel Composite Spherical Granulates with Catalytic Outer Layer and Improved Conversion Efficiency and Selectivity
Authors: Schmidt F. , Klemm H. , Schönfeld K. , Gerds A. , Hungerbach W. , Van Lookeren Campagne C. J. , Kaskel S. 
Published: March 2012

AbstractThe granulation procedure of a catalyst powder is a crucial step in designing a high‐quality catalyst granulate for industrial applications. New granulation processes have been developed that make it possible to form granulates with a very narrow particle size distribution and high sphericity. The innovative granulation techniques offer a great potential to produce layered catalysts with inert cores and an active shell. The novel spherical granules consist of an inexpensive inert core coated with an active catalyst material. New core shell granules with an accurately designed spherical geometry have been synthesized and compared to conventional homogeneous spherical granules of the same shape. The conversion of methanol to olefins has been used as a test reaction to validate the efficiency of these promising granulates.
Full Characterization of Colloidal Solutions of Long‐Alkyl‐Chain‐Amine‐Stabilized ZnO Nanoparticles by NMR Spectroscopy: Surface State, Equilibria, and Affinity
Authors: Coppel Yannick , Spataro Grégory , Pagès Carole , Chaudret Bruno , Maisonnat André , Kahn Myrtil L. 
Published: March 2012

AbstractFull NMR characterization of ZnO nanoparticles (NPs) stabilized by various amines (hexadecylamine, dodecylamine, and octylamine) in C7D8 demonstrated that the surface of this apparently simple system was very complex. Using different NMR spectroscopic techniques (1H, PGSE‐NMR, diffusion‐filtered 1H NMR, NOESY, ROESY), we observed at least three different modes of interaction of the amines at the surface of the NPs, in thermodynamic equilibrium with the free amines, the relative populations of which varied with their concentration. The first mode corresponded to a strong interaction between a small amount of amine and the ZnO NPs (kdesorp≈13 s−1). The second mode corresponded to a weak interaction between the amines and the surface of the ZnO NPs (koff(2)≈50–60 s−1). The third, and weakest, mode of interaction corresponded to the formation of a second ligand shell by the amine around the NPs that was held together through van der Waals interactions (koff(1)≈25×105 s−1). The second and third modes were in fast exchange on the NMR timescales with the free amines. The strongly interacting amines at the NPs surface (first mode) were in slow exchange with the other modes. A complex hydrogen‐bonding network at the NPs surface was also observed, which did not only involve the coordinated amine but also THF and water molecules that remained from the synthesis.
Amphiphilic Schiff Base Organogels: Metal‐Ion‐Mediated Chiral Twists and Chiral Recognition
Authors: Jin Qingxian , Zhang Li , Zhu Xuefeng , Duan Pengfei , Liu Minghua 
Published: March 2012

AbstractNew amphiphilic gelators that contained both Schiff base and L‐glutamide moieties, abbreviated as o‐SLG and p‐SLG, were synthesized and their self‐assembly in various organic solvents in the absence and presence of metal ions was investigated. Gelation test revealed that o‐SLG formed a thermotropic gel in many organic solvents, whilst p‐SLG did not. When metal ions, such as Cu2+, Zn2+, Mg2+, Ni2+, were added, different behaviors were observed. The addition of Cu2+ induced p‐SLG to from an organogel. In the case of o‐SLG, the addition of Cu2+ and Mg2+ ions maintained the gelating ability of the compound, whilst Zn2+ and Ni2+ ions destroyed the gel. In addition, the introduction of Cu2+ ions caused the nanofiber gel to perform a chiral twist, whilst the Mg2+ ions enhanced the fluorescence of the gel. More interestingly, the Mg2+‐ion‐mediated organogel showed differences in the fluorescence quenching by D‐ and L‐tartaric acid, thus showing a chiral recognition ability.
Study of the Contributions of Non‐Specific and Specific Interactions during Fluoxetine Adsorption onto Activated Carbons
Authors: Román Silvia , Nabais João Manuel Valente , González Juan Félix , González‐García Carmen María , Ortiz Angel Luis 
Published: March 2012

AbstractThe adsorption of fluoxetine onto activated carbons (ACs) prepared from almond tree pruning by steam and CO2 activation under different temperature conditions (650–950°C), was studied. In both series increasing the temperature caused an increase in the BET apparent surface area, yielding ACs with SBET up to 870 and 710 m2 g−1 after steam and CO2 activation, respectively. Also, a slight widening of the porosity was found in both cases. In order to modify the functionality of the ACs, two of them were impregnated with triethylenediamine (TEDA) prior to the adsorption process, which caused a decrease in the AC apparent surface mainly due to micropore blockage. The fluoxetine adsorption isotherms at 25°C showed maximum adsorption capacities between 110 and 224 mg g−1. The adsorption isotherms were analyzed using Langmuir and Freundlich models. Although the impregnation reduced the pore volume, it did not cause a decrease in the fluoxetine maximum adsorption capacity, but a modification in the adsorption mechanism was observed.