bluuebunny/crossref_metadata_2025_split huggingface dataset:
Suppression of humoral immune responses by 2,3,7,8-tetrachlorodibenzo-p-dioxin intercalated in smectite clay
Authors: Boyd Stephen A , Johnston Cliff T , Pinnavaia Thomas J , Kaminski Norbert E , Teppen Brian J , Li Hui , Khan Bushra , Crawford Robert B , Kovalova Natalia , Kim Seong-Su , Shao Hua , Gu Cheng , Kaplan Barbara L.F 
Published: October 2011

Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a highly toxic environmental contaminant found in soils and sediments. Because of its exceptionally low water solubility, this compound exists predominantly in the sorbed state in natural environments. Clay minerals, especially expandable smectite clays, are one of the major component geosorbents in soils and sediments that can function as an effective adsorbent for environmental dioxins, including TCDD. In this study, TCDD was intercalated in the smectite clay saponite by an incipient wetness method. The primary goal of this study was to intercalate TCDD in natural K-saponite clay and evaluate its immunotoxic effects in vivo. The relative bioavailability of TCDD was evaluated by comparing the metabolic activity of TCDD administered in the adsorbed state as an intercalate in saponite and freely dissolved in corn oil. This comparison revealed nearly identical TCDD-induced suppression of humoral immunity, a well-established and sensitive sequela, in a mammalian (mouse) model. This result suggests that TCDD adsorbed by clays is likely to be available for biouptake and biodistribution in mammals, consistent with previous observations of TCDD in livestock exposed to dioxin-contaminated ball clays that were used as feed additives. Adsorption of TCDD by clay minerals does not appear to mitigate risk associated with TCDD exposure substantially. Environ. Toxicol. Chem. 2011;30:2748–2755. © 2011 SETAC
Solubility of nano-zinc oxide in environmentally and biologically important matrices
Authors: Reed Robert B. , Ladner David A. , Higgins Christopher P. , Westerhoff Paul , Ranville James F. 
Published: October 2011

Abstract
Increasing manufacture and use of engineered nanoparticles is leading to a greater probability for release of engineered nanoparticles into the environment and exposure to organisms. In particular, zinc oxide (ZnO) is toxic, although it is unclear whether this toxicity is due to the zinc oxide nanoparticles, dissolution to Zn2+, or some combination thereof. The goal of this study was to determine the relative solubilities of both commercially available and in-house synthesized ZnO in matrices used for environmental fate and transport or biological toxicity studies. Dissolution of ZnO was observed in nanopure water (7.18–7.40 mg/L dissolved Zn, as measured by filtration) and Roswell Park Memorial Institute medium (RPMI-1640) (∼5 mg/L), but much more dissolution was observed in Dulbecco's modified Eagle's medium, in which the dissolved Zn concentration exceeded 34 mg/L. Moderately hard water exhibited low Zn solubility, likely because of precipitation of a Zn carbonate solid phase. Precipitation of a Zn-containing solid phase in RPMI also appeared to limit Zn solubility. Equilibrium conditions with respect to ZnO solubility were not apparent in these matrices, even after more than 1,000 h of dissolution. These results suggest that solution chemistry exerts a strong influence on ZnO dissolution and can result in limits on Zn solubility from precipitation of less soluble solid phases. Environ. Toxicol. Chem. 2012;31:93–99. © 2011 SETAC
Methodological considerations for testing the ecotoxicity of carbon nanotubes and fullerenes: Review
Authors: Petersen Elijah J. , Henry Theodore B. 
Published: October 2011

Abstract
The recent emergence of manufactured nanoparticles (NPs) that are released into the environment and lead to exposure in organisms has accelerated the need to determine NP toxicity. Techniques for measuring the toxicity of NPs (nanotoxicology) in ecological receptors (nanoecotoxicology) are in their infancy, however, and establishing standardized ecotoxicity tests for NPs are presently limited by several factors. These factors include the extent of NP characterization necessary (or possible) before, during, and after toxicity tests such that toxic effects can be related to physicochemical characteristics of NPs; determining uptake and distribution of NPs within exposed organisms (does uptake occur or are effects exerted at organism surfaces?); and determining the appropriate types of controls to incorporate into ecotoxicity tests with NPs. In this review, the authors focus on the important elements of measuring the ecotoxicity of carbon NPs (CNPs) and make recommendations for ecotoxicology testing that should enable more rigorous interpretations of collected data and interlaboratory comparisons. This review is intended to serve as a next step toward developing standardized tests that can be incorporated into a regulatory framework for CNPs. Environ. Toxicol. Chem. 2012;31:60–72. © 2011 SETAC
Reproductive and behavioral responses of earthworms exposed to nano-sized titanium dioxide in soil
Authors: McShane Heather , Sarrazin Manon , Whalen Joann K. , Hendershot William H. , Sunahara Geoffrey I. 
Published: October 2011

Abstract
Nanometer-sized titanium dioxide (nano-TiO2) is found in a number of commercial products; however, its effects on soil biota are largely unknown. In the present study, earthworms (Eisenia andrei and Eisenia fetida) were exposed to three types of commercially available, uncoated TiO2 nanomaterials with nominal diameters of 5, 10, and 21 nm. Nanomaterials were characterized for particle size, agglomeration, surface charge, chemical composition, and purity. Standard lethality, reproduction, and avoidance tests, as well as a juvenile growth test, were conducted in artificial soil or field soil amended with nano-TiO2 by two methods, liquid dispersion and dry powder mixing. All studies included a micrometer-sized TiO2 control. Exposure to field and artificial soil containing between 200 and 10,000 mg nano-TiO2 per kilogram of dry soil (mg/kg) had no significant effect (p &gt; 0.05) on juvenile survival and growth, adult earthworm survival, cocoon production, cocoon viability, or total number of juveniles hatched from these cocoons. However, earthworms avoided artificial soils amended with nano-TiO2. The lowest concentration at which avoidance was observed was between 1,000 and 5,000 mg nano-TiO2 per kilogram of soil, depending on the TiO2 nanomaterial applied. Furthermore, earthworms differentiated between soils amended with 10,000 mg/kg nano-TiO2 and micrometer-sized TiO2. A positive relationship between earthworm avoidance and TiO2 specific surface area was observed, but the relationship between avoidance and primary particle size was not determined because of the agglomeration and aggregation of nano-TiO2 materials. Biological mechanisms that may explain earthworm avoidance of nano-TiO2 are discussed. Results of the present study indicate that earthworms can detect nano-TiO2 in soil, although exposure has no apparent effect on survival or standard reproductive parameters. Environ. Toxicol. Chem. 2012;31:184–193. © 2011 SETAC
A mild and efficient protocol for oxidation of thiols to disulfides in water
Authors: Dewan Anindita , Bora Utpal , Kakati Dilip K. 
Published: October 2011

AbstractA novel vanadium polyoxometalate [(C7H7)(CH3)3N]3[H3V10O28].3H2O works as a useful oxidant for the oxidation of thiols to disulfldes in water under mild reaction conditions in an excellent yield. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 23:231–234, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.20760
Vitamin D deficiency in obese rats exacerbates nonalcoholic fatty liver disease and increases hepatic resistin and toll-like receptor activation
Authors: Roth Christian L. , Elfers Clinton T. , Figlewicz Dianne P. , Melhorn Susan J. , Morton Gregory J. , Hoofnagle Andrew , Yeh Matthew M. , Nelson James E. , Kowdley Kris V. 
Published: October 2011

Abstract

Childhood obesity is associated with type 2 diabetes mellitus and nonalcoholic fatty liver disease (NAFLD). Recent studies have found associations between vitamin D deficiency (VDD), insulin resistance (IR), and NAFLD among overweight children. To further explore mechanisms mediating these effects, we fed young (age 25 days) Sprague-Dawley rats with a low-fat diet (LFD) alone or with vitamin D depletion (LFD+VDD). A second group of rats was exposed to a Westernized diet (WD: high-fat/high-fructose corn syrup) that is more typically consumed by overweight children, and was either replete (WD) or deficient in vitamin D (WD+VDD). Liver histology was assessed using the nonalcoholic steatohepatitis (NASH) Clinical Research Network (CRN) scoring system and expression of genes involved in inflammatory pathways were measured in liver and visceral adipose tissue after 10 weeks. In VDD groups, 25-OH-vitamin D levels were reduced to 29% (95% confidence interval [CI]: 23%-36%) compared to controls. WD+VDD animals exhibited significantly greater hepatic steatosis compared to LFD groups. Lobular inflammation as well as NAFLD Activity Score (NAS) were higher in WD+VDD versus the WD group (NAS: WD+VDD 3.2 ± 0.47 versus WD 1.50 ± 0.48, P < 0.05). Hepatic messenger RNA (mRNA) levels of Toll-like receptors (TLR)2, TLR4, and TLR9, as well as resistin, interleukins (IL)-1β, IL-4, and IL-6 and oxidative stress marker heme oxygenase (HO)-1, were higher in WD+VDD versus WD animals (P < 0.05). Logistic regression analyses showed significant associations between NAS score and liver mRNA levels of TLRs 2, 4, and 9, endotoxin receptor CD14, as well as peroxisome proliferator activated receptor (PPAR)γ, and HO-1. Conclusion: VDD exacerbates NAFLD through TLR-activation, possibly by way of endotoxin exposure in a WD rat model. In addition it causes IR, higher hepatic resistin gene expression, and up-regulation of hepatic inflammatory and oxidative stress genes. (Hepatology 2012)
Natural Bond Orbital Rationalizations of NMR Observations for Metal‐Ligand Bonding (II): Rehybridization of Phosphorus Arising from Coordination of Methyl‐Phenyl‐Phosphines
Authors: Su Wei‐Lin , Huang Hsiu‐Ping , Chen Wei‐Ting , Hsu Wen‐Yi , Chang Hsi‐Yen , Ho Szu‐Yu , Wang Shao‐Pin , Shyu Shin‐Guang 
Published: October 2011

AbstractCarbonyls' 2π orbital populations, [2π], in W(CO)5L {L = PPh3, PPh2Me, PPhMe2} have been determined by NMR spin‐lattice relaxation techniques. Experimental values of axial [2π], compared with those reported for PMe3 and P(OMe)3, reveal that PMe3 is a slightly better π‐acid than PPh3. Through space interactions between carbonyl and phenyl groups are insignificant since values of [2π] do not vary significantly in the series of phosphines, going from PMep3 to PPh3. Natural bond orbital (NBO) studies indicate that π‐accepting capabilities for these phosphines are primarily governed by the nature of P‐C anti‐bonding, σ*P‐C. Compared with PPh3, the better π‐accepting σ*P‐C, as well as the better s‐donating lone‐pair LP(P), in PMe3 can both be explained by the higher extents of rehybridization of the coordinated phosphorus atom. Based on this rehybridization argument, the NBO predicted order of increasing π‐acidic strengths PPh3 < PPh2Me < PPhMe2 < PMe3, which cannot be clearly distinguished by NMR experiments, is ascribed to the same NBO trend of σ‐donating capabilities in a synergistic manner. Effects of coordination on P‐Y (Y = C, O, F) bonding strengths in phosphines (or phosphites) are depending on two conflicting effects: rehybridization of LP(P) and the hyperconjugative‐like dπ → σ*P‐Y back‐donation.
Validated Method for the Simultaneous Determination of Gemifloxacin and H2‐receptor Antagonists in Bulk, Pharmaceutical Formulations and Human Serum by RP‐HPLC; In‐vitro Applications
Authors: Sultana Najma , Arayne M. Saeed , Shamim Sana , Naz Asia 
Published: October 2011

AbstractSimple, isocratic and rapid RP‐HPLC method has been developed for the simultaneous analysis of gemifloxacin and H2‐receptor antagonists i.e. Cimetidine, Famotidine and Ranitidine, in bulk, pharmaceutical formulation and human serum. Separation was achieved on the RP‐Mediterranea column [C18 (250 × 4.6 mm, 5 μ)] at ambient temperature using mobile phase consisting of acetonitrile: methanol: water (20:28:52 v/v/v pH 2.8 adjusted by phosphoric acid). Flow rate was 1.0 mL/min with an average operating pressure of 180 kg/cm2. Gatifloxacin (GATI) was used as an internal standard (IS). Quantitation was achieved with UV detection at 221, 256 and 267 nm, respectively. Linear calibration curves, at concentration ranges of 0.05‐37.5 μgmL‐L with a correlation coefficient of ±0.9994. The detection and quantification limits were in the ranges of 0.023‐0.250 μgmL‐L and 0.071‐0.756 μgmL‐L, respectively. Friedman's and Student's t‐test were applied to correlate these results. Method was validated in terms of selectivity, linearity, precision, robustness, recovery, limits of detection and quantitation and is applicable to the routine analysis of GFX and H2‐receptor antagonists, alone or in combination.
Implementation of a TORS program in an academic medical center
Authors: Richmon Jeremy D. , Agrawal Nishant , Pattani Kavita M. 
Published: October 2011

AbstractObjectives:Transoral robotic surgery (TORS) is rapidly being adopted by many head and neck surgeons for treatment of upper aerodigestive tract tumors. Various obstacles exist to efficiently implement this novel surgical technique in a busy academic center. We present our experience to illustrate one approach to initiating a TORS program.Study Design:Prospective cohort study.Methods:A clear, stepwise approach to introduce TORS in our hospital was devised prior to scheduling the first case. Upon initiation of the program, various time points and surgical outcomes were measured for all patients undergoing TORS.Results:The first 20 cases of TORS at Johns Hopkins Hospital are reviewed. Room setup time averaged 24 minutes (±12). Presurgery time averaged 22 ± 10 minutes. Positioning time averaged 38 ± 13 minutes. Operative time (OT) averaged 71 ± 54 minutes. The total time in room (TTR) averaged 242 ± 84 minutes. There were no significant differences (P > .5) in any of the time measurements above between the first and second 10 cases or the first 15 and last 5 cases. Negative margins (both frozen and permanent) were obtained in all ablative cases. No patient required a tracheotomy and no procedure was aborted secondary to inability to expose the tumor. The average hospitalization time was 1.3 days. All patients were discharged on oral diets. There were no long‐term surgical complications.Conclusions:The introduction of a TORS program in an academic medical center can be a complex and daunting undertaking. We demonstrate that with careful planning, excellent efficiency and safety can be attained immediately.
Effective use of physician extenders in an outpatient otolaryngology setting
Authors: Norris Byron , Harris Tristen , Stringer Scott 
Published: October 2011

AbstractPhysician extenders may be a valuable asset to an outpatient otolaryngology practice. The adjunctive care provided by physician extenders appears to be cost effective and has the advantages of increasing patient education, promoting physician productivity, and improving management of chronic conditions. Practice types that may benefit from advanced practice providers include group or solo practices with high demand or who need improved efficiency. We discuss five different practice models for incorporation of advanced practice providers in an outpatient otolaryngology practice. These models include scribe, collaborative, limited independent, partial independent, and near complete independent practice and are based primarily on the autonomy level of the physician extender. In additon, we examine available literature discussing the cost effectiveness of physician extenders used in an outpatient setting.
Application of the control volume mixed finite element method to a triangular discretization
Authors: Naff R.L. 
Published: October 2011

SUMMARYA two‐dimensional control volume mixed finite element method is applied to the elliptic equation. Discretization of the computational domain is based in triangular elements. Shape functions and test functions are formulated on the basis of an equilateral reference triangle with unit edges. A pressure support based on the linear interpolation of elemental edge pressures is used in this formulation. Comparisons are made between results from the standard mixed finite element method and this control volume mixed finite element method. Published 2011. This article is a US Government work and is in the public domain in the USA.
A level‐set‐based large sliding contact algorithm for easy analysis of implant positioning
Authors: Andreykiv Andriy , van Keulen Fred , Rixen Daniel J. , Valstar Edward 
Published: October 2011

SUMMARYA finite element analysis of implant positioning inside a bone requires the creation of many meshes that model various implant orientations. This process can be very labour intensive and is difficult to automate. In order to facilitate this type of modelling, we present a large sliding contact algorithm that does not require the creation of a conforming discretization for the bone. The cavity inside the bone, necessary to accommodate the implant, is modelled with a Heaviside function calculated on the level set field, which is defined in terms of material coordinates of the bone. The algorithm is based on the minimization of the energy functional with a constraint term, formulated as in classical contact mechanics; however, instead of the distance function, we use the above‐mentioned level set function. The presented numerical 2D and 3D examples validate the algorithm against the solutions obtained with commercial finite element software. Copyright © 2011 John Wiley & Sons, Ltd.
Autophagy and disease: always two sides to a problem
Authors: Sridhar Sunandini , Botbol Yair , Macian Fernando , Cuervo Ana Maria 
Published: October 2011

AbstractAutophagy is a process traditionally known to contribute to cellular cleaning through the removal of intracellular components in lysosomes. In recent years, intensive scrutiny at the molecular level to which autophagy has been subjected has also contributed to expanding our understanding of the physiological role of this pathway. Added to the well‐characterized role in quality control, autophagy has proved to be important in the maintenance of cellular homeostasis and of the energetic balance, in cellular and tissue remodelling, and cellular defence against extracellular insults and pathogens. It is not a surprise that, in light of this growing number of physiological functions, connections between autophagic malfunction and human pathologies have also been strengthened. In this review, we focus on several pathological conditions associated with primary or secondary defects in autophagy and comment on a recurring theme for many of them, ie the fact that autophagy can often exert both beneficial and aggravating effects on the progression of disease. Elucidating the factors that determine the switch between these dual functions of autophagy in disease has become a priority when considering the potential therapeutic implications of the pharmacological modulation of autophagy in many of these pathological conditions. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Lewis acidic polypropylene for compatibilization of polypropylene/microsilica composites
Authors: Lipponen Sami , Nykänen Antti , Ruokolainen Janne , Seppälä Jukka 
Published: October 2011

AbstractPolypropylene (PP) was compounded with submicron size silica filler particles (microsilica, μSi) up to 30 wt‐%. In addition, three external compatibilizers, with characteristic functionalities, were studied to examine their influence in the mechanical properties of the PP/μSi composites. As a result, the modulus of the composite increased while the other tensile values deteriorated in correlation with increased filler concentration. The addition of an external compatibilizer reduced this deterioration, but the reduction was dependent on the type of the compatibilizer used. The influence of an acid functionalized compatibilizer was unsubstantial while the fluorosilane and the Lewis acidic phenylsilane functionalized polypropylenes acted as effective compatibilizers. In addition to examining the tensile properties, the toughness of the composites was evaluated as well. The microsilica filler was found to act as toughening agent since the Brittle‐to‐Ductile transition point of the composite increased by 2‐3 orders of magnitude at high filler concentrations. However, this increase in the toughness was rapidly lost when an effective compatibilizer was used to bind the filler with the matrix. This observation was consistent with the common understanding of the filler toughening mechanism, where particle‐matrix debonding is a prerequisite for facilitating the plastic stretch of the polymer ligaments between filler particles. In our case, however, the few filler aggregates in the polymer matrix also played a crucial role. While in uncompatibilized composites the filler aggregates remained passive (could not be seen at the fracture surface), the addition of an effective compatibilizer activated these aggregates to promote crack initiation and/or propagation. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers
Novel POBD‐modified organoclay and its polyimide nanocomposites for removal of the Co(II) ion
Authors: Mansoori Yagoub , Fathollahi Kobra , Reza Zamanloo Mohammad , Imanzadeh Gholamhassan 
Published: October 2011

AbstractAn organophilic clay has been obtained via cation exchange reaction between sodium montmorillonite and the hydrochloride salt of 2‐(5‐(3,5‐diaminophenyl)‐1,3,4‐oxadiazole‐2‐yl)pyridine, POBD. Thermogravimetric analysis (TGA) showed that thermal decomposition of the organophilic clay starts at about 350°C, which shows that it is quite thermally stable compared with conventional montmorillonite modified with aliphatic long chain surfactants. POBD‐modified organoclay almost quantitatively removed the Co(II) ion from aqueous solution at pH = 10.0 (Qt = 3.00 mg g−1, R = 98.2%). A series of polyimide/clay nanocomposite materials (PCNs) consisting of POBD and benzophenone‐3,3′,4,4′‐tetracarboxylic dianhydride, BTDA were also prepared by an in situ polymerization reaction via thermal imidization. POBD‐modified organoclay was used as a surfactant at different concentrations. Intercalation of polymer chains within the organoclay galleries was confirmed by WXRD. Both the glass transition temperature and thermal stability are increased with respect to pristine PI at low clay concentrations. At high clay loadings, the aggregation of organoclay particles results in a decrease in Tg and thermal stability. In the SEM images of PCN 1 and 3%, too many micro cracks are observed in the background, and a flower‐shape pattern spreads uniformly over the entire surface. The maximum Co(II) uptake capacity and efficiency were observed at pH 10.0 within a 40‐h period for both PI and PCN films. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers