bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation of High‐Quality MCM‐48 Mesoporous Silica and the Mode of Action of the Template
Authors: Zhang Kun , Yuan En‐Hui , Xu Lang‐Lang , Xue Qing‐Song , Luo Chen , Albela Belén , Bonneviot Laurent 
Published: August 2012

AbstractUltrastable MCM‐48 silica with Ia3d cubic structure was synthesized by using only the surfactant cetyltrimethylammonium tosylate (CTATos) as template at extremely low surfactant concentration (CTATos/SiO2 = 0.068). Characterization by small‐angle X‐ray diffraction (XRD), nitrogen adsorption, and high‐resolution transmission electron microscopy (HRTEM) clearly shows that the obtained MCM‐48 silica has a highly ordered structure and large surface area (ca. 1281 m2/g) and pore volume (ca. 1.07 cm3/g). The regular cubic arrays were well retained even after this material was calcined at a high temperature of 900 °C for 3 h or heated at reflux in boiling water for 12 h. The Fourier transform infrared (FTIR) spectrum, thermogravimetric analysis (TG), and chemical analysis provide strong evidence that the formation of MCM‐48 is attributed to the retention of tosylate (Tos–) counteranions of the surfactant in the interface between surfactant and silicate. The current synthetic strategy is suitable for routine and large‐scale preparations of mesoporous silica with different topological structures.
Arene‐Ruthenium(II) and Bis(allyl)‐Ruthenium(IV) Complexes Containing 2‐(Diphenylphosphanyl)pyridine Ligands: Potential Catalysts for Nitrile Hydration Reactions?
Authors: García‐Álvarez Rocío , García‐Garrido Sergio E. , Díez Josefina , Crochet Pascale , Cadierno Victorio 
Published: August 2012

AbstractNeutral arene‐ruthenium(II) complexes [RuCl2(η6‐arene){κ1‐(P)‐PPh2py}] and [RuCl2(η6‐arene){κ1‐(P)‐PPh2(py‐4‐NMe2)}] (arene = benzene,p‐cymene, mesitylene, hexamethylbenzene) have been synthesized and studied as potential catalysts for the selective hydration of nitriles to amides using benzonitrile as a model substrate. The effectiveness of these complexes was low due to the high tendency of the 2‐(diphenylphosphanyl)pyridine ligands to form stable κ2‐(P,N)‐chelate rings, as demonstrated by NMR spectroscopy and catalytic experiments performed with the isolated cationic derivatives [RuCl(η6‐arene){κ2‐(P,N)‐P N}][SbF6] [P N = PPh2py, PPh2(py‐4‐NMe2)]. Despite its reluctance to adopt a chelating κ2‐(P,N) coordination mode, cooperative effects of the bulky 2‐(diphenylphosphanyl)pyridine ligand PPh2(py‐6‐tert‐amyl) were not observed in complexes [RuCl2(η6‐arene){κ1‐(P)‐PPh2(py‐6‐tert‐amyl)}] (arene = benzene,p‐cymene). The novel bis(allyl)‐ruthenium(IV) derivatives [RuCl(η3:η3‐C10H16){κ2‐(P,N)‐P N}][SbF6] [P N = PPh2py, PPh2(py‐4‐NMe2)] and [RuCl2(η3:η3‐C10H16){κ1‐(P)‐PPh2(py‐6‐tert‐amyl)}] (C10H16= 2,7‐dimethylocta‐2,6‐diene‐1,8‐diyl) were also synthesized and fully characterized, and again led to modest conversions in the benzonitrile hydration reaction. Improvements in the catalytic activities of complexes [RuCl2(η6‐p‐cymene){κ1‐(P)‐PPh2py}], [RuCl(η6‐p‐cymene){κ2‐(P,N)‐PPh2py}][SbF6] and [RuCl(η3:η3‐C10H16){κ2‐(P,N)‐PPh2py}][SbF6] were observed in the presence of excess PPh2py due to the in situ formation of the catalytically more active dication [Ru{κ2‐(P,N)‐PPh2py}3]2+.
Tolanophane Revisited – Resolution and Racemization Mechanism of a Twisted Chiral Aromatic Compound
Authors: Toyota Shinji , Kawai Katsutoshi , Iwanaga Tetsuo , Wakamatsu Kan 
Published: August 2012

AbstractEnantiomers of tolanophane consisting of two tolane units were resolved by chiral HPLC, contrary to the previous attempts by Staab et al. Racemization took place rapidly at room temperature, and the barrier to enantiomerization was determined to be 93.2 kJ mol–1 at 283 K. This energy barrier was rationally deduced with a mechanism involving rotations about the single and triple bond axes, as revealed by DFT calculations. A tetrahedrane intermediate resulting from a transannular reaction between the two adjacent triple bonds was ruled out.
An Investigation of the Transdiagnostic Model of Eating Disorders in the Context of Muscle Dysmorphia
Authors: Murray Stuart B. , Rieger Elizabeth , Karlov Lisa , Touyz Stephen W. 
Published: August 2012

AbstractAimMuscle dysmorphia is a psychiatric disorder that has been conceptually linked to eating disorders, although its precise nosology remains unclear. To further investigate this notion, the present study examined the applicability of the transdiagnostic model of eating disorders to muscle dysmorphia.MethodOne hundred and nineteen male undergraduate students completed self‐report measures of multidimensional perfectionism, mood intolerance, self‐esteem, interpersonal problems, and muscle dysmorphia symptomatology.ResultsSelf‐oriented perfectionism, socially prescribed perfectionism, mood intolerance, and low self‐esteem significantly predicted muscle dysmorphia symptomatology, whereas other‐oriented perfectionism and interpersonal problems did not demonstrate significant predictive value when accounting for the other transdiagnostic constructs.DiscussionThe transdiagnostic model of eating disorders may potentially be applied to enhance our understanding of the maintenance of muscle dysmorphic features in addition to eating disorder symptomatology. Copyright © 2012 John Wiley & Sons, Ltd and Eating Disorders Association.
Aquatic toxicity of nanosilver colloids to different trophic organisms: Contributions of particles and free silver ion
Authors: Wang Zhuang , Chen Jingwen , Li Xuehua , Shao Jianping , Peijnenburg Willie J.G.M. 
Published: August 2012

Abstract
The wide uses of nanosilver (nAg) have resulted in concerns regarding ecotoxicity to aquatic organisms. Some previous studies have found that the toxicity of nAg is due to the nanoparticles themselves, while others have found that ionic silver (Ag+) released by nAg particles plays an important role. In the present study, the authors quantitatively evaluated the relative contribution of nAg particles and Ag+ to the toxicity to three aquatic organisms of different trophic levels, including an algal species (Raphidocelis subcapitata), a cladoceran species (Chydorus sphaericus), and a freshwater fish larva (Danio rerio). A bare and a polyvinylpyrrolidone (PVP)–coated nAg as well as a monodispersed nAg with a dispersant (DIS-nAg) were examined. The toxicity of the nAg in the form of colloids decreased in the order DIS-nAg &gt; PVP-nAg &gt; Bare-nAg for all three trophic aquatic organisms (in terms of median effect concentration). The DIS-nAg had the highest and Bare-nAg the lowest concentration of free Ag+, implying that free Ag+ cannot be neglected in explaining the toxicity of nAg colloids. Furthermore, the contribution of free Ag+ to the toxicity of nAg colloids for R. subcapitata was the highest but for D. rerio the lowest, implying that the organisms tested have different accumulation abilities for Ag+ or nAg particles. Environ. Toxicol. Chem. 2012; 31: 2408–2413. © 2012 SETAC
Methods for predicting the rate constant for uptake of organic chemicals from water by fish
Authors: Brooke David N. , Crookes Michael J. , Merckel Daniel A.S. 
Published: August 2012

Abstract
Bioaccumulation is an important information requirement for chemicals risk assessment. The most widely used test guideline for measuring bioaccumulation in fish is the OECD 305 test guideline and, in the future, it is likely to include a dietary exposure method for substances that are difficult to test by the more usual aqueous exposure route. This new method results in a biomagnification factor (BMF), whereas for regulatory purposes a bioconcentration factor (BCF) is often required. Therefore, being able to estimate a BCF quantitatively from the data generated in the dietary study would meet an accepted regulatory need. The information generated by the dietary study includes the depuration rate constant. To use these data to estimate a BCF, an estimate of the rate constant for uptake from water is needed, allowing a kinetic BCF to be calculated. The present study considers and tests methods that are currently available for predicting uptake rate constants from water using a database of bioconcentration data. A number of methods were found to perform similarly when tested with substances with a log KOW range of approximately 3.5 to 8.2. The uncertainty in the estimated uptake rate constant was relatively large, however, even for the best performing methods. Environ. Toxicol. Chem. 2012; 31: 2465–2471. © 2012 SETAC
Side chain influencing the interaction between β‐cyclodextrin and vanillin
Authors: Zeng Zhangfu , Fang Yanxiong , Ji Hongbing 
Published: August 2012

ABSTRACTThe reason for low encapsulation efficiency of vanillin compared to p‐hydroxybenzaldehyde within β‐cyclodextrin was investigated. Fourier transform infrared spectra proved intermolecular interaction between guest and β‐cyclodextrin. UV–visible studies indicated that vanillin and p‐hydroxybenzaldehyde form 1:1 inclusion complexes with β‐cyclodextrin. Nuclear magnetic resonance and quantum computational methods gave the most favourable orientation in which the guest molecule (vanillin or p‐hydroxybenzaldehyde) is totally sequestered in the hydrophobic cavity of the cyclodextrin with the phenolic end located near the primary hydroxyls of the β‐cyclodextrin and the aldehyde group near the secondary hydroxyls with hydrogen bonding formation. Encapsulation efficiency of the β‐cyclodextrin inclusion with vanillin is about 29% lower than that with p‐hydroxybenzaldehyde. This result could be attributable to the effect that the side chain methoxy group weakened the guest/host non‐covalent intermolecular interaction, specifically, hydrogen bond interaction. Copyright © 2012 John Wiley & Sons, Ltd.
Recent advances in carbon dioxide capture with metal‐organic frameworks
Authors: Liu Yangyang , Wang Zhiyong U. , Zhou Hong‐Cai 
Published: August 2012

AbstractUncontrolled massive release of the primary greenhouse gas carbon dioxide (CO2) into atmosphere from anthropogenic activities poses a big threat and adversely affects our global climate and natural environment. One promising approach to mitigate CO2 emission is carbon capture and storage (CCS), in which ideal adsorbent materials with high storage capacity and excellent adsorption selectivity over other gases are urgently needed. For practical applications in CO2 capture from flue gas of power plants, the biggest single contributor of anthropogenic CO2 emission, the adsorbent materials must also be chemically stable, be easy to regenerate with minimal energy input, and be easily synthesized with low capital cost. Metal‐organic frameworks (MOFs), highly crystalline porous materials constructed by metal ions and organic ligands, have emerged as a class of excellent adsorbent materials for carbon capture. Great progress in MOF materials for CO2 capture has been made in the past and reviewed accordingly, but new discoveries are constantly being made as the field quickly grows. In this paper, we provide a short review on the most recent advances in using MOFs for CO2 adsorption, storage, and separation that are directly related to CO2 capture. Some of the important properties of MOF adsorbents which are crucial for practical applications but are largely overlooked in research carried out so far are discussed. © 2012 Society of Chemical Industry and John Wiley & Sons, Ltd
Astrocytic CX43 hemichannels and gap junctions play a crucial role in development of chronic neuropathic pain following spinal cord injury
Authors: Chen Michael J. , Kress Benjamin , Han Xiaoning , Moll Katherine , Peng Weiguo , Ji Ru‐Rong , Nedergaard Maiken 
Published: August 2012

AbstractChronic neuropathic pain is a frequent consequence of spinal cord injury (SCI). Yet despite recent advances, upstream releasing mechanisms and effective therapeutic options remain elusive. Previous studies have demonstrated that SCI results in excessive ATP release to the peritraumatic regions and that purinergic signaling, among glial cells, likely plays an essential role in facilitating inflammatory responses and nociceptive sensitization. We sought to assess the role of connexin 43 (Cx43) as a mediator of CNS inflammation and chronic pain. To determine the extent of Cx43 involvement in chronic pain, a weight‐drop SCI was performed on transgenic mice with Cx43/Cx30 deletions. SCI induced robust and persistent neuropathic pain including heat hyperalgesia and mechanical allodynia in wild‐type control mice, which developed after 4 weeks and was maintained after 8 weeks. Notably, SCI‐induced heat hyperalgesia and mechanical allodynia were prevented in transgenic mice with Cx43/Cx30 deletions, but fully developed in transgenic mice with only Cx30 deletion. SCI‐induced gliosis, detected as upregulation of glial fibrillary acidic protein in the spinal cord astrocytes at different stages of the injury, was also reduced in the knockout mice with Cx43/Cx30 deletions, when compared with littermate controls. In comparison, a standard regimen of post‐SCI treatment of minocycline attenuated neuropathic pain to a significantly lesser degree than Cx43 deletion. These findings suggest Cx43 is critically linked to the development of central neuropathic pain following acute SCI. Since Cx43/Cx30 is expressed by astrocytes, these findings also support an important role of astrocytes in the development of chronic pain. © 2012 Wiley Periodicals, Inc.
Proinflammatory cytokine regulation of cyclic AMP‐phosphodiesterase 4 signaling in microglia in vitro and following CNS injury
Authors: Ghosh Mousumi , Garcia‐Castillo Daniela , Aguirre Vladimir , Golshani Roozbeh , Atkins Coleen M. , Bramlett Helen M. , Dietrich W. Dalton , Pearse Damien D. 
Published: August 2012

AbstractCyclic AMP suppresses immune cell activation and inflammation. The positive feedback loop of proinflammatory cytokine production and immune activation implies that cytokines may not only be regulated by cyclic AMP but also conversely regulate cyclic AMP. This study examined the effects of tumor necrosis factor (TNF)‐α and interleukin (IL)‐1β on cyclic AMP‐phosphodiesterase (PDE) signaling in microglia in vitro and after spinal cord injury (SCI) or traumatic brain injury (TBI). TNF‐α or IL‐1β stimulation produced a profound reduction (>90%) of cyclic AMP within EOC2 microglia from 30 min that then recovered after IL‐1β but remained suppressed with TNF‐α through 24 h. Cyclic AMP was also reduced in TNF‐α‐stimulated primary microglia, albeit to a lesser extent. Accompanying TNF‐α‐induced cyclic AMP reductions, but not IL‐1β, was increased cyclic AMP‐PDE activity. The role of PDE4 activity in cyclic AMP reductions was confirmed by using Rolipram. Examination of pde4 mRNA revealed an immediate, persistent increase in pde4b with TNF‐α; IL‐1β increased all pde4 mRNAs. Immunoblotting for PDE4 showed that both cytokines increased PDE4A1, but only TNF‐α increased PDE4B2. Immunocytochemistry revealed PDE4B nuclear translocation with TNF‐α but not IL‐1β. Acutely after SCI/TBI, where cyclic AMP levels are reduced, PDE4B was localized to activated OX‐42+ microglia; PDE4B was absent in OX‐42+ cells in uninjured spinal cord/cortex or inactive microglia. Immunoblotting showed PDE4B2 up‐regulation from 24 h to 1 wk post‐SCI, the peak of microglia activation. These studies show that TNF‐α and IL‐1β differentially affect cyclic AMP‐PDE signaling in microglia. Targeting PDE4B2 may be a putative therapeutic direction for reducing microglia activation in CNS injury and neurodegenerative diseases. © 2012 Wiley Periodicals, Inc.
HIV‐1 alters neural and glial progenitor cell dynamics in the central nervous system: Coordinated response to opiates during maturation
Authors: Hahn Yun Kyung , Podhaizer Elizabeth M. , Hauser Kurt F. , Knapp Pamela E. 
Published: August 2012

AbstractHIV‐associated neurocognitive disorders (HANDs) are common sequelae of human immunodeficiency virus (HIV) infection, even when viral titers are well controlled by antiretroviral therapy. Evidence in patients and animal models suggests that neurologic deficits are increased during chronic opiate exposure. We have hypothesized that central nervous system (CNS) progenitor cells in both adult and developing CNS are affected by HIV infection and that opiates exacerbate these effects. To examine this question, neural progenitors were exposed to HIV‐1 Tat1–86 in the developing brain of inducible transgenic mice and in vitro. We examined whether Tat affected the proliferation or balance of progenitor populations expressing nestin, Sox2, and Olig2. Disease relevance was further tested by exposing human‐derived progenitors to supernatant from HIV‐1 infected monocytes. Studies concentrated on striatum, a region preferentially targeted by HIV and opiates. Results were similar among experimental paradigms. Tat or HIV exposure reduced the proliferation of undifferentiated (Sox2+) progenitors and oligodendroglial (Olig2+) progenitors. Coexposure to morphine exacerbated the effects of Tat or HIV‐1SF162 supernatant, but partially reversed HIV‐1IIIB supernatant effects. Populations of Sox2+ and Olig2+ cells were also reduced by Tat exposure, although progenitor survival was unaffected. In rare instances, p24 immunolabeling was detected in viable human progenitors by confocal imaging. The vulnerability of progenitors is likely to distort the dynamic balance among neuron/glial populations as the brain matures, perhaps contributing to reports that neurologic disease is especially prevalent in pediatric HIV patients. Pediatric disease is atypical in developed regions but remains a serious concern in resource‐limited areas where infection occurs commonly at birth and through breast feeding. © 2012 Wiley Periodicals, Inc.
Effects of managed care mechanisms on access to healthcare: results from a qualitative study in Colombia
Authors: Vargas Ingrid , Unger Jean‐Pierre , Mogollón‐Pérez Amparo Susana , Vázquez M. Luisa 
Published: August 2012

SUMMARYBackgroundManaged competition has underpinned most health sector reforms aimed at improving access and efficiency, in Latin America and other countries. The aim of the paper is to analyse barriers to healthcare that emerge from the introduction of managed care mechanisms in Colombia.MethodsQualitative, exploratory, and descriptive‐interpretative research was carried out on the basis of case studies of four healthcare networks, comprised of insurers and their providers. Individual semi‐structured interviews were conducted with a theoretical sample of informants (managers, professionals, and users), between 24 and 61 per network. The final sample size was reached by saturation of information. An inductive thematic content analysis was conducted. The study areas were two municipalities of Colombia, in which most of the population live in poverty.ResultsA number of managed care mechanisms that act as barriers to access were identified by all informants, regardless of area and type of insurance regime. These mechanisms act directly on the patient (authorizations, fragmented insurance) or on the providers (purchasing mechanisms or limits to medical practice). The predominant mechanism appears to be related to the type of agreement established between insurers and providers. The reason for these barriers, according to informants, is insurers' search for profitability. As a consequence, there is delay in or no access to adequate treatment. This is particularly evident in secondary care.ConclusionA variety of managed care strategies that effectively hinder access to healthcare have been introduced by insurers, casting doubt on the usefulness of their application in low‐income countries and profit‐making contexts. Copyright © 2012 John Wiley & Sons, Ltd.
Fibrin‐chitosan composite substrate for in vitro culture of chondrocytes
Authors: Gamboa‐Martínez T. C. , García Cruz D. M. , Carda C. , Ribelles J. L. Gómez , Ferrer G. Gallego 
Published: August 2012

AbstractThe aim of this study was to develop a biocompatible monolayer substrate based on fibrin and chitosan for in vitro culture of chondrocytes. Fibrin‐chitosan composite substrates combined the proved cell adhesion properties of fibrin with the hydrophilicity and poor adhesion capacity of chitosan. Chitosan microspheres were produced by coacervation method, agglomerated within a fibrin network and subsequently crosslinked with genipin. The composite substrate was stable for 28 days of culture due to the high crosslinking density. Human chondrocytes cultured on the composite substrate were viable during the culture period. At the end of culture time (28 days) the composite substrate showed low cellular proliferation, 41% more collagen type II and 13% more production of sulfated glycosaminoglycans with respect to the amounts found at 14 days. The study revealed that dedifferentiated chondrocytes cultured in monolayer on the composite substrate can re‐acquire characteristics of differentiated cells without using three‐dimensional substrates or chondrogenic media. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013.
Biofunctionalization of titanium surface with multilayer films modified by heparin‐VEGF‐fibronectin complex to improve endothelial cell proliferation and blood compatibility
Authors: Wang H. G. , Yin T. Y. , Ge S. P. , Zhang Q. , Dong Q. L. , Lei D. X. , Sun D. M. , Wang G. X. 
Published: August 2012

AbstractIn‐stent restenosis and subsequent thrombosis remain a significant complication following the implantation of coronary stents. Different approaches have been used in developing novel coronary stents to protect against thrombosis and minimize restenosis. In the present study, we designed a biomacromolecular layer‐by‐layer coating with heparin, vascular endothelial growth factor (VEGF), and fibronectin onto nickel‐free titanium surface to improve blood compatibility and endothelial cell proliferation. The multilayer assembling process was monitored by water contact angle and surface plasmon resonance, respectively. With increasing the number of layers, the deposition of polyelectrolyte as self‐assembled ultrathin multilayer films showed linear growth of absorbance. In vitro blood compatibility results revealed that the fabricated layers prolonged activated partial thrombin time and prothrombin time, reduced platelets activation and aggregation, and reduced blood hemolysis rate. Cell adhesion and growth results showed that the assembled multilayer films significantly promoted cell attachment and growth, and the endothelialization property of the multilayer films was preferable compared with the untreated titanium disk. In conclusion, these results suggest that titanium surface modification using biofunctional multilayer films composed of heparin, VEGF, and fibronectin may serve as a potential approach to inhibit thrombosis and promote re‐endothelialization of cardiovascular stents. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013.