bluuebunny/crossref_metadata_2025 huggingface dataset:
Gas Mixing in the Airways and Airspaces
Authors: Verbanck Sylvia , Paiva Manuel
Published: April 2011

Basic physical concepts of diffusion, convection, and dispersion pertaining to gas transport in the human airways are reviewed. Their incorporation into quantitative models of gas mixing is presented, also illustrating the crucial interaction of gas transport equations with the model geometry. Model simulations are confronted with the available experimental gas mixing indices such as the phase III slope obtained in normal human lungs, with some pertinent examples in laboratory animals and in human lung disease. The use of inert gases with differing diffusion coefficients and their associated phase III slope provides invaluable experimental information on gas mixing in the lungs, with the concept of the diffusion front playing a central role. Sources of inter‐ and intraregional ventilation heterogeneity can be related to the location of the diffusion front, which offers the possibility to distinguish between ventilation heterogeneity proximal to the diffusion front (driven by convection between lung units larger than acini) and more peripheral ventilation heterogeneity (driven by diffusion‐convection interaction mainly within the acinus). While specific ventilation distribution and flow asynchrony co‐act to generate convection‐dependent ventilation heterogeneity, local structural asymmetry of the acinar air spaces is sufficient to generate diffusion‐convection‐dependent ventilation heterogeneity. The remaining hiatus in our understanding of ventilation heterogeneity in the human lung is described, together with some potential perspectives for its investigation. © 2011 American Physiological Society.Compr Physiol1:809‐834, 2011.
Urea Transport in the Kidney
Authors: Klein Janet D. , Blount Mitsi A. , Sands Jeff M.
Published: April 2011

Urea transport proteins were initially proposed to exist in the kidney in the late 1980s when studies of urea permeability revealed values in excess of those predicted by simple lipid‐phase diffusion and paracellular transport. Less than a decade later, the first urea transporter was cloned. Currently, theSLC14Afamily of urea transporters contains two major subgroups:SLC14A1, the UT‐B urea transporter originally isolated from erythrocytes; andSLC14A2, the UT‐A group with six distinct isoforms described to date. In the kidney, UT‐A1 and UT‐A3 are found in the inner medullary collecting duct; UT‐A2 is located in the thin descending limb, and UT‐B is located primarily in the descending vasa recta; all are glycoproteins. These transporters are crucial to the kidney's ability to concentrate urine. UT‐A1 and UT‐A3 are acutely regulated by vasopressin. UT‐A1 has also been shown to be regulated by hypertonicity, angiotensin II, and oxytocin. Acute regulation of these transporters is through phosphorylation. Both UT‐A1 and UT‐A3 rapidly accumulate in the plasma membrane in response to stimulation by vasopressin or hypertonicity. Long‐term regulation involves altering protein abundance in response to changes in hydration status, low protein diets, adrenal steroids, sustained diuresis, or antidiuresis. Urea transporters have been studied using animal models of disease including diabetes mellitus, lithium intoxication, hypertension, and nephrotoxic drug responses. Exciting new animal models are being developed to study these transporters and search for active urea transporters. Here we introduce urea and describe the current knowledge of the urea transporter proteins, their regulation, and their role in the kidney. © 2011 American Physiological Society.Compr Physiol1:699‐729, 2011.
Both CD62 and CD162 antibodies prevent formation of CD36‐dependent platelets, rosettes, and artefactual pseudoexpression of platelet markers on white blood cells: A study with ImageStream®
Authors: Ouk Catherine , Jayat‐Vignoles Chantal , Donnard Magali , Feuillard Jean
Published: April 2011

Fluorescent labeled monoclonal antibodies (mAbs) against CD36 are routinely used as monocyte, erythroid, or platelet markers in clinical cytometry. CD36 has recently been proposed by various authors as a valuable marker helping to enumerate leukocyte's subpopulations by flow cytometry. However, it is known that binding of CD36 may induce platelet activation and formation of platelet's rosettes on leukocytes, resulting in false expression of platelet markers on white blood cells. To study this phenomenon, we have combined classical flow cytometry and a new quantitative flow imaging technique with the ImageStream® analyzer. We show that CD36 ligation induces activation of platelets with CD62 expression and their adhesion on leukocytes due to CD62 and CD162 interactions. Preincubation of whole blood samples with either anti‐CD62 or anti‐CD162 antibodies could prevent formation of these rosettes. Our approach also emphasizes the fact that immunomorphological analysis of cell events with ImageStream technology is a useful tool to validate the specificity of marker's labeling or to elucidate incoherent results obtained with classical flow cytometry. We thus propose to prevent false platelet labeling on leukocytes by preincubation with either anti‐CD62 or anti‐CD162 antibodies when using CD36 mAbs. © 2011 International Society for Advancement of Cytometry
Synthesis, Structure, and Photochemistry of an Organic Heptamolybdate‐Monomolybdate
Authors: Wutkowski Adam , Srinivasan Bikshandarkoil R. , Naik Ashish R. , Schütt Christian , Näther Christian , Bensch Wolfgang
Published: April 2011

Treatment of MoO3 with butan‐1‐amine (BuNH2) or pyrrolidine (PyrNH2) results in the formation of (BuNH3)8[(Mo7O24)(MoO4)]·3H2O (1; BuNH3 = butan‐1‐aminium) or (PyrNH2)6[(Mo7O24]·2H2O (2; PyrNH2 = pyrrolidinium), respectively. On irradiation with sunlight, compound 1, which is an organic heptamolybdate [Mo7O24]6– that contains a cocrystallized monomolybdate [MoO4]2– in the same compound, is transformed to an oxido‐bridged diheptamolybdate (BuNH3)10[(Mo7O22)(μ2‐O)2(Mo7O22)]·5.5H2O (1b). The [Mo7O24]6– units in 1 and 2 are made up of edge‐sharing [MoO6] octahedra, whereas the central unit in 1b is a bis(μ2‐O)‐bridged heptamolybdate dimer. Hydrogen bonding among the lattice water molecules in 1 results in the formation of a water octamer, whereas hydrogen bonding between the lattice water molecules and [Mo7O24]6– in 2 results in the formation of a one‐dimensional water‐linked heptamolybdate chain. Supramolecular structures, photochemistry, and thermal properties of 1, 1b, and 2 are reported. For comparison of photochemical behavior, two more polyoxomolybdates, (PrNH3)6[Mo7O24]·3H2O (3; PrNH3 = propan‐1‐aminium) and (PentNH3)6[Mo7O24]·3H2O (4; PentNH3 = pentan‐1‐aminium), were prepared and characterized.
Synthesis and Characterization of Homoleptic and Heteroleptic Cobalt, Nickel, Copper, Zinc and Cadmium Compounds with the 2‐(Tosylamino)‐N‐[2‐(tosylamino)benzylidene]aniline Ligand
Authors: Sousa‐Pedrares Antonio , Viqueira Joaquin A. , Antelo Jorge , Labisbal Elena , Romero Jaime , Sousa Antonio , Nascimento Otaciro R. , García‐Vázquez José A.
Published: April 2011

The electrochemical oxidation of anodic metal (cobalt, nickel, copper, zinc and cadmium) in an acetonitrile solution of the Schiff‐base ligand 2‐(tosylamino)‐N‐[2‐(tosylamino)benzylidene]aniline (H2L) afforded the homoleptic compounds [ML]. The addition of 1,1‐diphenylphosphanylmethane (dppm), 2,2′‐bipyridine (bipy) or 1,10‐phenanthroline (phen) to the electrolytic phase gave the heteroleptic complexes [NiL(dppm)], [ML(bipy)] and [ML(phen)]. The crystal structures of H2L (1), [NiL] (2), [CuL] (3), [NiL(dppm)] (4), [CoL(phen)] (5), [CuL(bipy)] (6) and [Zn(Lphen)] (7) were determined by X‐ray diffraction. The homoleptic compounds [NiL] and [CuL] are mononuclear with a distorted square planar [MN3O] geometry with the Schiff base acting as a dianionic (NamideNamideNimineOtosyl) tetradentate ligand. Both compounds exhibit an unusual π–π stacking interaction between a six‐membered chelate ring containing the metal and a phenylic ring of the ligand. In the heteroleptic complex [NiL(dppm)], the nickel atom is in a distorted tetrahedral [NiN3P] environment defined by the imine, two amide nitrogen atoms of the L2– dianionic tridentate ligand and one of the phosphorus atoms of the dppm molecule. In the other heteroleptic complexes, [CoL(phen)], [CuL(bipy)] and [ZnL(phen)], the metal atom is in a five‐coordinate environment defined by the imine, two amide nitrogen atoms of the dianionic tridentate ligand and the two bipyridine or phenanthroline nitrogen atoms. The compounds were characterized by microanalysis, IR and UV/Vis (Co, Ni and Cu complexes) spectroscopy, FAB mass spectrometry and 1H NMR ([NiL] and Zn and Cd complexes) and EPR spectroscopy (Cu complexes).
Antioxidant and aldose reductase inhibition activity of Ligustrum japonicum and Olea europaea L. leaf extracts
Authors: Papoti Vassiliki T. , Pegklidou Kyriaki , Perifantsi Eleftheria , Nenadis Nikolaos , Demopoulos Vassilios J. , Tsimidou Maria Z.
Published: April 2011

Ligustrum japonicum and Olea europaea leaf extracts prepared via domestic techniques were studied for antioxidant and aldose reductase inhibitory activity (ARI) in relation to individual phenol/flavonoid composition (HPLC‐various detection means) and content. On the same extract weight basis L. japonicum leaf extracts, poorer in total polar phenol (TPP) content and in most cases in flavonoids, were less efficient than olive leaf extracts in radical scavenging and in retarding lipid oxidation. On the same TPP content basis, the former were of comparable efficiency in radical scavenging but exhibited lower activity than the latter in bulk oils or liposomes. L. japonicum extracts were characterized by the presence of verbascoside and apigenin derivatives, whereas O. europaea extracts by that of oleuropein. Superiority of L. japonicum infusion versus O. europaea infusion was evidenced using the ARI activity assay either on the same extract weight or on TPP content basis. The former was also superior in comparison to oleuropein, tyrosol, and hydroxytyrosol activity. These findings suggest the presence of other active compounds besides the so far identified phenolics and enhance our view on the importance of Oleaceae plants as sources of bioactive compounds beyond O. europaea.

Practical applications: Oleaceae plants are a unique source for the secoiridoid oleuropein or verbascoside that confer well documented biological properties. On continuation of our effort to valorize plants of this family as sources for functional constituents we examined, in parallel, leaf extracts of the less investigated species Ligustrum japonicum versus those of Olea europaea L. The data presented for the extracts obtained via domestic preparations techniques (infusions, decoctions, tinctures) are expected to attract the interest of those involved in herbal teas and dietary supplements sector.
Efficient Room‐Temperature One‐Pot Synthesis of 2‐Amino‐3‐alkyl(3‐aryl)quinazolin‐4(3H)‐ones
Authors: Lecoutey Cédric , Fossey Christine , Rault Sylvain , Fabis Frédéric
Published: April 2011

Starting from anthranilates, the one‐pot successive addition of ethoxycarbonylisothiocyanate, alkyl‐ or arylamines, and the coupling reagent EDCI led to the clean, room‐temperature formation of carbamate‐protected 2‐amino‐3‐alkyl(3‐aryl)quinazolin‐4(3H)‐ones in up to 93 % yield. This method provides a practical alternative to previously reported procedures for the synthesis of 2‐amino‐3‐substituted quinazolin‐4(3H)‐ones.
Dynamic response and optimal design of structures with large mass ratio TMD
Authors: De Angelis Maurizio , Perno Salvatore , Reggio Anna
Published: April 2011

This paper investigates the dynamic behavior and the seismic effectiveness of a non‐conventional Tuned Mass Damper (TMD) with large mass ratio. Compared with conventional TMD, the device mass is increased up to be comparable with the mass of the structure to be protected, aiming at a better control performance. In order to avoid the introduction of an excessive additional weight, masses already present on the structure are converted into tuned masses, retaining structural or architectural functions beyond the mere control function. A reduced order model is introduced for design purposes and the optimal design of a large mass ratio TMD for seismic applications is then formulated. The design method is specifically developed to implement High‐Damping Rubber Bearings (HDRB) to connect the device mass to the main structure, taking advantage of combining stiffness and noticeable damping characteristics. Ground acceleration is modeled as a Gaussian random process with white noise power spectral density. A numerical searching technique is used to obtain the optimal design parameter, the frequency ratio alpha, which minimizes the root‐mean‐square displacement response of the main structure. The study finally comprises shaking table tests on a 1:5 scale model under a wide selection of accelerograms, both artificial and natural, to assess the seismic effectiveness of the proposed large mass ratio TMD. Copyright © 2011 John Wiley & Sons, Ltd.
The Influence of Pt Loading, Support and Nafion Content on the Performance of Direct Methanol Fuel Cells: Examined on the Example of the Cathode
Authors: Xue X. , Bock C. , Birry L. , MacDougall B. R.
Published: April 2011

Nano‐sized Pt colloids were prepared using the polyol method and supported on Ketjen black EC 600J (KB), Vulcan XC‐72 (VC) and high surface area graphite 300 (HG). The effects of the Nafion ionomer content, and the Pt loading of the cathode catalyst layer as well as the Pt loading on the support on the performance of direct methanol fuel cells (DMFCs), were studied. The membrane electrode assemblies (MEAs) were analysed using current–voltage curves, cyclic voltammetry, electrochemical impedance spectroscopy (EIS) and adsorbed CO stripping voltammetry. Optimum Nafion to carbon (N/C) ratios (N/C being defined as the weight ratio of the Nafion ionomer to the carbon) were determined. The optimum N/C ratios were found to depend on the support as follows, 1.4, 0.7 and 0.5 for Pt/KB, Pt/VC and Pt/HG, respectively and to be independent of the Pt/C loading range of 20–80 wt% tested in this work. The highest DMFC performances, as well as the highest electrochemical active surface areas, and improved gas diffusivities, were achieved using these ratios. For the catalysts prepared in this work, the average Pt crystallite size was found to decrease with increasing surface area of the support for a particular Pt loading. MEAs made using KB as support and the optimal N/C ratio of 1.4 showed the best performances, i.e. higher than the VC and HG supports for any N/C ratio. The highest DMFC performance was observed using 60 wt% Pt on KB cathode electrodes of 1 mg Pt cm–2loading and an N/C value of 1.4. For all three supports studied, the 60 wt% Pt on carbon loading resulted in the best DMFC performance. This may be linked to the Pt particle size and catalyst preparation method used in this work. In comparison to literature results, high DMFC performances were achieved using relatively ‘low' Pt and Ru loadings. For example, a maximum power density of >100 mW cm–2at 60 °C was observed using a 1 mg Pt cm–2cathode loading and a 2 mg PtRu cm–2anode loading.
p14Arf acts as an antagonist of HMGA2 in senescence of mesenchymal stem cells—implications for benign tumorigenesis
Authors: Markowski Dominique Nadine , Winter Nina , Meyer Frauke , von Ahsen Inga , Wenk Heiner , Nolte Ingo , Bullerdiek Jörn
Published: April 2011

HMGA2 is a major regulator of benign tumorigenesis from mesenchyme‐derived tissues and stem‐cell self‐renewal. It has been postulated that HMGA2 mediates its critical function by decreasing p16Ink4a/p14Arf expression and cellular senescence. To repress the oncogenic activity of HMGA2, the lin‐28‐let‐7 axis is thought to increasingly repress the expression of HMGA2 with age. To understand the HMGA2‐p14Arf‐relationship in benign tumorigenesis, we performed a series of experiments on mesenchymal stem‐cells, i.e., the proposed cells of origin of lipomas and uterine leiomyomas. The expression of both genes was inversely correlated during senescence in vitro but contrary to the expectations in adipose tissue derived stem cells (ADSCs) stimulation of HMGA2 by FGF1 increased the expression of p14Arf. Based on the assumption that in ADSCs p14Arf is repressing HMGA2, siRNA silencing of p14Arf was performed resulting in a significant upregulation of HMGA2. To see if p14Arf can repress HMGA2 by a TP53‐dependent mechanism, nutlin‐3, a known MDM2 antagonist, was used which not only increased the activity of the senescence, associated markers p21 and beta‐galactosidase, but also decreased the expression of HMGA2, suggesting that p14Arf indeed influences HMGA2 by a p53‐dependent mechanism because nutlin‐3 stabilizes p53. Accordingly, the HMGA2 response triggered by serum was reduced by treatment of ADSCs with nutlin‐3. As to the interaction between HMGA2 and p14Arf in benign tumorigenesis, we propose a model where akin to MSC self‐renewal during tissue repair the simultaneous increase of p14Arf with HMGA2 ensures genomic stability, whereas in turn p14Arf can repress HMGA2 via TP53. © 2011 Wiley‐Liss, Inc.
Selenoprotein S expression in reactive astrocytes following brain injury
Authors: Fradejas Noelia , Del Carmen Serrano‐PÉREZ Maria , Tranque Pedro , Calvo Soledad
Published: April 2011

Selenoprotein S (SelS) is an endoplasmic reticulum (ER)‐resident protein involved in the unfolded protein response. Besides reducing ER‐stress, SelS attenuates inflammation by decreasing pro‐inflammatory cytokines. We have recently shown that SelS is responsive to ischemia in cultured astrocytes. To check the possible association of SelS with astrocyte activation, here we investigate the expression of SelS in two models of brain injury: kainic acid (KA) induced excitotoxicity and cortical mechanical lesion. The regulation of SelS and its functional consequences for neuroinflammation, ER‐stress, and cell survival were further analyzed using cultured astrocytes from mouse and human. According to our immunofluorescence analysis, SelS expression is prominent in neurons and hardly detectable in astrocytes from control mice. However, brain injury intensely upregulates SelS, specifically in reactive astrocytes. SelS induction by KA was evident at 12 h and faded out after reaching maximum levels at 3–4 days. Analysis of mRNA and protein expression in cultured astrocytes showed SelS upregulation by inflammatory stimuli as well as ER‐stress inducers. In turn, siRNA‐mediated SelS silencing combined with adenoviral overexpression assays demonstrated that SelS reduces ER‐stress markers CHOP and spliced XBP‐1, as well as inflammatory cytokines IL‐1β and IL‐6 in stimulated astrocytes. SelS overexpression increased astrocyte resistance to ER‐stress and inflammatory stimuli. Conversely, SelS suppression compromised astrocyte viability. In summary, our results reveal the upregulation of SelS expression in reactive astrocytes, as well as a new protective role for SelS against inflammation and ER‐stress that can be relevant to astrocyte function in the context of inflammatory neuropathologies. © 2011 Wiley‐Liss, Inc.
Targeted downregulation of N‐acetylgalactosamine 4‐sulfate 6‐O‐sulfotransferase significantly mitigates chondroitin sulfate proteoglycan‐mediated inhibition
Authors: Karumbaiah Lohitash , Anand Sanjay , Thazhath Rupal , Zhong Yinghui , Mckeon Robert J. , Bellamkonda Ravi V.
Published: April 2011

Chondroitin sulfate‐4,6 (CS‐E) glycosaminoglycan (GAG) upregulation in astroglial scars is a major contributor to chondroitin sulfate proteoglycan (CSPG)‐mediated inhibition [Gilbert et al. (2005) Mol Cell Neurosci 29:545–558]. However, the role of N‐acetylgalactosamine 4‐sulfate 6‐O‐sulfotransferase (GalNAc4S6ST) catalyzed sulfation of CS‐E, and its contribution to CSPG‐mediated inhibition of CNS regeneration remains to be fully elucidated. Here, we used in situ hybridization to show localized upregulation of GalNAc4S6ST mRNA after CNS injury. Using in vitro spot assays with immobilized CS‐E, we demonstrate dose‐dependent inhibition of rat embryonic day 18 (E18) cortical neurons. To determine whether selective downregulation of CS‐E affected the overall inhibitory character of extracellular matrix produced by reactive astrocytes, single [against (chondroitin 4) sulfotransferase 11 (C4ST1) or GalNAc4S6ST mRNA] or double [against C4ST1 and GalNAc4S6ST mRNA] siRNA treatments were conducted and assayed using quantitative real‐time polymerase chain reaction and high‐performance liquid chromatography to confirm the specific downregulation of CS‐4S GAG (CS‐A) and CS‐E. Spot and Bonhoeffer stripe assays using astrocyte‐conditioned media from siRNA‐treated rat astrocytes showed a significant decrease in inhibition of neuronal attachment and neurite extensions when compared with untreated and TGFα‐treated astrocytes. These findings reveal that selective attenuation of CS‐E via siRNA targeting of GalNAc4S6ST significantly mitigates CSPG‐mediated inhibition of neurons, potentially offering a novel intervention strategy for CNS injury. © 2011 Wiley‐Liss, Inc.
Are measurements from excised leaves suitable for modeling diurnal patterns of gas exchange of intact leaves?
Authors: Miyazawa Yoshiyuki , Tateishi Makiko , Komatsu Hikaru , Kumagai Tomo'omi , Otsuki Kyoichi
Published: April 2011

To examine the feasibility of using ecophysiological data from excised leaves for a meteorological simulation model of gas exchange, we compared the obtained gas exchange rates and the modelled ones using excised leaves and those using intact leaves. Instantaneous gas exchange rates of excised leaves and stomatal control in response to environmental conditions were not significantly different from those of attached leaves. Modelled gas exchange rates based on excised leaf data showed a good fit to the diurnal patterns of in situ measurements. This suggests that use of excised leaf data to predict gas exchange of intact leaves is permissible as long as the effects of excision are pre‐screened as described in this paper. Copyright © 2011 John Wiley & Sons, Ltd.
Synthetic Studies toward Communesins
Authors: Zuo Zhiwei , Ma Dawei
Published: April 2011

Communesins A–H are a growing family of natural products isolated from a marine fungal strain of Penicillium species. Preliminary biological evaluation has revealed that these compounds possess insecticidal activity and cytotoxicity against several tumor cell lines. Their interesting biological activities and unique structures have attracted considerable attention of synthetic chemists worldwide. To date, several elegant protocols for assembling the core structure of these indole alkaloids have been described, including intermolecular Diels–Alder reaction of methylated aurantioclavine with quinine methide imine and intramolecular hetero Diels–Alder reaction of the azaortho‐xylylene intermediates. Recently, three completed total syntheses for communesin F have been disclosed, in which the crucial vicinal quaternary stereogenic centers were constructed by employing an intramolecular cyclopropanation; an intramolecular Heck reaction of a tetrasubstituted alkene, or an oxidative coupling of a 3‐substituted indole, as the key step. Accompanying the total synthesis, the absolute configuration of natural communesin F was established as 6R,7R,8R,9S,11R. However, total syntheses of other members of communesin family that contain an epoxide moiety have not been achieved, which will stimulate more synthetic studies.
Total Syntheses of Kapakahines E and F
Authors: Rainier Jon D. , Espejo Vinson R.
Published: April 2011

This article describes the synthesis of kapakahines E and F, along with what we believe to be a general method for the total synthesis of the kapakahine family of marine natural products. The method utilizes a unique heterodimerization reaction between bromopyrroloindolines and indole nucleophiles, a novel pyrroloindoline‐to‐α‐carboline rearrangement, and a Negishi coupling reaction of C(3)‐iodoindoles.
Triclosan: environmental exposure, toxicity and mechanisms of action
Authors: Dann Andrea B. , Hontela Alice
Published: April 2011

Triclosan [5‐chloro‐2‐(2,4‐dichlorophenoxy)phenol; TCS] is a broad spectrum antibacterial agent used in personal care, veterinary, industrial and household products. TCS is commonly detected in aquatic ecosystems, as it is only partially removed during the wastewater treatment process. Sorption, biodegradation and photolytic degradation mitigate the availability of TCS to aquatic biota; however the by‐products such as methyltriclosan and other chlorinated phenols may be more resistant to degradation and have higher toxicity than the parent compound. The continuous exposure of aquatic organisms to TCS, coupled with its bioaccumulation potential, have led to detectable levels of the antimicrobial in a number of aquatic species. TCS has been also detected in breast milk, urine and plasma, with levels of TCS in the blood correlating with consumer use patterns of the antimicrobial. Mammalian systemic toxicity studies indicate that TCS is neither acutely toxic, mutagenic, carcinogenic, nor a developmental toxicant. Recently, however, concern has been raised over TCS's potential for endocrine disruption, as the antimicrobial has been shown to disrupt thyroid hormone homeostasis and possibly the reproductive axis. Moreover, there is strong evidence that aquatic species such as algae, invertebrates and certain types of fish are much more sensitive to TCS than mammals. TCS is highly toxic to algae and exerts reproductive and developmental effects in some fish. The potential for endocrine disruption and antibiotic cross‐resistance highlights the importance of the judicious use of TCS, whereby the use of TCS should be limited to applications where it has been shown to be effective. Copyright © 2011 John Wiley & Sons, Ltd.
Subchronic inhalation toxicity of iron oxide (magnetite, Fe3O4) in rats: pulmonary toxicity is determined by the particle kinetics typical of poorly soluble particles
Authors: Pauluhn Jürgen
Published: April 2011

Wistar rats were nose‐only exposed to pigment‐sized iron oxide dust (Fe3O4, magnetite) in a subchronic 13‐week inhalation study according to the OECD testing guidelines TG#413 and GD#39. A 4 week pilot study with a 6 month post exposure period served as basis for validating the kinetic modeling approaches utilized to design the subchronic study. Kinetic analyses made during this post exposure period demonstrated that a diminution in particle clearance and lung inflammation occurred at cumulative exposure levels exceeding the lung overload threshold. Animals were exposed 6 h per day, five days per week for 13 consecutive weeks at actual concentrations of 0, 4.7, 16.6 and 52.1 mg m−3 (mass median aerodynamic diameter ≈1.3 μm, geometric standard deviation = 2). The exposure to iron oxide dust was tolerated without mortality, consistent changes in body weights, food and water consumption or systemic toxicity. While general clinical pathology and urinalysis were unobtrusive, hematology revealed changes of unclear toxicological significance (minimally increased differential neutrophil counts in peripheral blood). Elevations of neutrophils in bronchoalveolar lavage (BAL) appeared to be the most sensitive endpoint of study. Histopathology demonstrated responses to particle deposition in the upper respiratory tract (goblet cell hyper‐ and/or metaplasia, intraepithelial eosinophilic globules in the nasal passages) and the lower respiratory tract (inflammatory changes in the bronchiolo‐alveolar region). Consistent changes suggestive of pulmonary inflammation were evidenced by BAL, histopathology, increased lung and lung‐associated‐lymph node (LALN) weights at 16.6 and 52.1 mg m−3. Increased septal collagenous fibers were observed at 52.1 mg m−3. Particle translocation into LALN occurred at exposure levels causing pulmonary inflammation. In summary, the retention kinetics iron oxide reflected that of poorly soluble particles. The empirical no‐observed‐adverse‐effect level (NOAEL) and the lower bound 95% confidence limit on the benchmark concentration (BMCL) obtained by benchmark analysis was 4.7 and 4.4 mg m−3, respectively, and supports an OEL (time‐adjusted chronic occupational exposure level) of 2 mg m−3 (alveolar fraction). Copyright © 2011 John Wiley & Sons, Ltd.
Monitoring temporal development and healing of diabetic foot ulceration using hyperspectral imaging
Authors: Yudovsky Dmitry , Nouvong Aksone , Schomacker Kevin , Pilon Laurent
Published: April 2011

This study combines non‐invasive hyperspectral imaging with an experimentally validated skin optical model and inverse algorithm to monitor diabetic feet of two representative patients. It aims to observe temporal changes in local epidermal thickness and oxyhemoglobin concentration and to gain insight into the progression of foot ulcer formation and healing. Foot ulceration is a debilitating comorbidity of diabetes that may result in loss of mobility and amputation. Inflammation and necrosis preempt ulceration and can result in changes in the skin prior to ulceration and during ulcer healing that affect oxygen delivery and consumption. Previous studies estimated oxyhemoglobin and deoxyhemoglobin concentrations around pre‐ulcerative and ulcer sites on the diabetic foot using commercially available hyperspectral imaging systems. These measurements were successfully used to detect tissue at risk of ulceration and predict the healing potential of ulcers. The present study shows epidermal thickening and decrease in oxyhemoglobin concentration can also be detected prior to ulceration at pre‐ulcerative sites. The algorithm was also able to observe reduction in the epidermal thickness combined with an increase in oxyhemoglobin concentration around the ulcer as it healed and closed. This methodology can be used for early prediction of diabetic foot ulceration in a clinical setting. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A computational study of the reactivities of four‐membered heavy carbene systems
Authors: Wu Chi‐Shiun , Su Ming‐Der
Published: April 2011

The potential energy surfaces for the chemical reactions of four‐membered N‐heterocyclic group 14 heavy carbene species have been studied using density functional theory (B3LYP/LANL2DZ). Five four‐membered group 14 heavy carbene species, (i‐Pr)2NP(NR)2E:, in which E = C, Si, Ge, Sn, and Pb, were chosen as the model reactants in this work. Also, four kinds of chemical reactions, CH bond insertion, water addition, alkene cycloaddition, and dimerization, have been used to study the chemical reactivities of these group 14 four‐membered N‐heterocyclic carbene species. Basically, our present theoretical work predicts that the larger the ∠NEN bond angle of the four‐membered group 14 heavy carbene species, the smaller the singlet‐triplet splitting, the lower the activation barrier, and, in turn, the more rapid, its chemical reactions to various chemical species. Moreover, our theoretical investigations suggest that the relative carbenic reactivity decreases in the order: C > Si > Ge > Sn > Pb. That is, the heavier the group 14 atom (E), the more stable is its four‐membered carbene toward chemical reactions. As a result, our results predict that the four‐membered group 14 heavy carbene species (E = Si, Ge, Sn, and Pb) should be more kinetically stable than the observed carbene species and, thus, can be also readily synthesized and isolated at room temperature. Furthermore, the singlet‐triplet energy splitting of the four‐membered group 14 carbene species, as described in the configuration mixing model attributed to the work of Pross and Shaik, can be used as a diagnostic tool to predict their reactivities. The results obtained allow a number of predictions to be made. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
A possible cause of decreasing summer rainfall in northeast Australia
Authors: Li Jianping , Feng Juan , Li Yun
Published: April 2011

The NCEP/NCAR reanalysis and precipitation data from the Australian Bureau of Meteorology are used to analyse variability in rainfall during the austral summer (December–March, DJFM) in northeast Australia (NEA). NEA rainfall shows a marked decrease over the past 50 years, mainly in the austral summer. Our analysis reveals that the summer rainfall decrease in NEA is generally an interdecadal phenomenon. The declining trend has an imprint in the tropical Australian summer monsoon (TASM). Not only does TASM have a phase‐to‐phase influence on NEA summer rainfall at the interannual scale, it is also closely linked with interdecadal variation in NEA summer rainfall. Thus, the decrease in NEA at the interdecadal scale could be attributed to corresponding variation in TASM. Moreover, the coupled linkage between TASM and NEA summer rainfall appears to be largely independent of El Niño–Southern Oscillation. One possible reason for the interdecadal weakening trend in TASM is a sustained interdecadal warming trend in sea surface temperature (SST) over the Wharton Basin (100°–130°E, 20°–5°S). When the Wharton Basin is in a cold state, anomalous westerlies occur in the lower troposphere in the TASM region, and cyclonic circulation anomalies and rising flows occur in the low and middle troposphere over NEA, which are associated with a strong TASM situation, consequently favouring enhanced rainfall over NEA; the opposite occurs in the case of a warm Wharton Basin. SST over the Wharton Basin has shown a continuous warming trend over the past 60 years, contributing to the weakening of TASM and, consequently, a decrease in NEA summer rainfall. Copyright © 2011 Royal Meteorological Society
Chondroprotective effect of alendronate in a rabbit model of osteoarthritis
Authors: Shirai Takaaki , Kobayashi Masahiko , Nishitani Kohei , Satake Tsuyoshi , Kuroki Hiroshi , Nakagawa Yasuaki , Nakamura Takashi
Published: April 2011

The aim of this study was to determine how alendronate (ALN) alters cartilage degeneration and periarticular bone quality in a rabbit anterior cruciate ligament transection (ACLT) model of osteoarthritis (OA). Thirty rabbits underwent an ACLT on the left knee and a sham operation on the right knee. Fifteen rabbits received weekly subcutaneous injections of ALN (0.14 mg/kg) and 15 rabbits (the control [cont] group) received saline. Animal knees were divided into four groups: cont/sham, cont/ACLT, ALN/sham, and ALN/ACLT. Histological, radiological, and immunohistochemical indices were evaluated for each group. Bone volume ratios by micro‐computed tomography showed that ALN prevented periarticular bone loss. Histologically, the cont/ACLT group had significantly worse cartilage damage than the cont/sham group 12 weeks after the surgery. However, the ALN/ACLT group had mild cartilage degeneration compared with that of the ALN/sham group. Immunohistochemical analysis showed that ALN suppressed the expression of matrix metalloproteinase‐13, interleukin‐1β, type‐X collagen, vascular endothelial growth factor, and receptor activator of nuclear factor κB ligand in OA cartilage. ALN had a chondroprotective effect in an experimental rabbit model of OA. © 2011 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 29: 1572–1577, 2011
Highly efficient release of lovastatin from poly(lactic‐co‐glycolic acid) nanoparticles enhances bone repair in rats
Authors: Ho Ming‐Hua , Chiang Chun‐Pin , Liu Yao‐Fang , Kuo Mark Yen‐Ping , Lin Sze‐Kwan , Lai Juin‐Yih , Lee Bor‐Shiunn
Published: April 2011

Lovastatin exhibits higher thermal stability and lower degradation rate than simvastatin. However, the amount of research studying a lovastatin delivery device has been far less than similar research on simvastatin. As a consequence, a high lovastatin release rate system has not been developed. We hypothesized that highly efficient release of lovastatin from poly(lactic‐co‐glycolic acid) (PLGA) nanoparticles in a short‐term release (7 days) could provide an effective delivery system for bone repair. This study optimized the emulsion (o/w) technique in the fabrication process for PLGA nanoparticles, thereby producing the first recorded case of a high release rate (97%) of lovastatin. We also calculated the calibration curve of lovastatin using a UV spectrometer. The results demonstrated that the ALPase activity in human osteoblasts could be significantly stimulated by lovastatin carried in PLGA nanoparticles, but was prominently decreased by free lovastatin with the concentration higher than 4 µg/ml. Animal studies showed that the amount of lovastatin contained in 1 mg PLGA was the optimum dosage. These results suggest the new lovastatin‐releasing PLGA delivery device exhibits potential for clinical treatment of bony defects. © 2011 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 29: 1504–1510, 2011
Assessment of the accuracy of infrared and electromagnetic navigation using an industrial robot: Which factors are influencing the accuracy of navigation?
Authors: Liodakis Emmanouil , Chu Kongfai , Westphal Ralf , Krettek Christian , Citak Musa , Gosling Thomas , Kenawey Mohamed
Published: April 2011

Our objectives were to detect factors that influence the accuracy of surgical navigation (magnitude of deformity, plane of deformity, position of the navigation bases) and compare the accuracy of infrared with electromagnetic navigation. Human cadaveric femora were used. A robot connected with a computer moved one of the bony fragments in a desired direction. The bases of the infrared navigation (BrainLab) and the receivers of the electromagnetic device (Fastrak‐Pohlemus) were attached to the proximal and distal parts of the bone. For the first part of the study, deformities were classified in eight groups (e.g., 0 to 5°). For the second part, the bases were initially placed near the osteotomy and then far away. The mean absolute differences between both navigation system measurements and the robotic angles were significantly affected by the magnitude of angulation with better accuracy for smaller angulations (p < 0.001). The accuracy of infrared navigation was significantly better in the frontal and sagittal plane. Changing the position of the navigation bases near and far away from the deformity apex had no significant effect on the accuracy of infrared navigation; however, it influenced the accuracy of electromagnetic navigation in the frontal plane (p < 0.001). In conclusion, the use of infrared navigation systems for corrections of small angulation‐deformities in the frontal or sagittal plane provides the most accurate results, irrespectively from the positioning of the navigation bases. © 2011 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 29: 1476–1483, 2011
A Raman spectroscopic study of the different vanadate groups in solid‐state compounds—model case: mineral phases vésigniéite [BaCu3(VO4)2(OH)2] and volborthite [Cu3V2O7(OH)2·2H2O]
Authors: Frost Ray L. , Palmer Sara J. , Čejka Jiří , Sejkora Jiří , Plášil Jakub , Bahfenne Silmarilly , Keeffe Eloise C.
Published: April 2011

Raman spectroscopy has been used to study vanadates in the solid state. The molecular structure of the vanadate minerals vésigniéite [BaCu3(VO4)2(OH)2] and volborthite [Cu3V2O7(OH)2·2H2O] have been studied by Raman spectroscopy and infrared spectroscopy. The spectra are related to the structure of the two minerals. The Raman spectrum of vésigniéite is characterized by two intense bands at 821 and 856 cm−1 assigned to ν1 (VO4)3− symmetric stretching modes. A series of infrared bands at 755, 787 and 899 cm−1 are assigned to the ν3 (VO4)3− antisymmetric stretching vibrational mode. Raman bands at 307 and 332 cm−1 and at 466 and 511 cm−1 are assigned to the ν2 and ν4 (VO4)3− bending modes. The Raman spectrum of volborthite is characterized by the strong band at 888 cm−1, assigned to the ν1 (VO3) symmetric stretching vibrations. Raman bands at 858 and 749 cm−1 are assigned to the ν3 (VO3) antisymmetric stretching vibrations; those at 814 cm−1 to the ν3 (VOV) antisymmetric vibrations; that at 508 cm−1 to the ν1 (VOV) symmetric stretching vibration and those at 442 and 476 cm−1 and 347 and 308 cm−1 to the ν4 (VO3) and ν2 (VO3) bending vibrations, respectively. The spectra of vésigniéite and volborthite are similar, especially in the region of skeletal vibrations, even though their crystal structures differ. Copyright © 2011 John Wiley & Sons, Ltd.
Micro‐Raman investigation of tin dioxide nanostructured material based on annealing effect
Authors: Sangeetha P. , Sasirekha V. , Ramakrishnan V.
Published: April 2011

Rutile‐structured nanocrystalline tin dioxide (SnO2) powder was synthesized by the chemical precipitation method using the precursor SnCl2• 5H2O. The SnO2 powder was annealed at different temperatures, namely, 600, 800 and 1000 °C. Micro‐Raman spectra were recorded for both the as‐grown and annealed SnO2 nanocrystalline samples. Micro‐Raman spectral measurements on the SnO2 nanoparticle show the first‐order Raman modes A1g (633 cm−1), E1g (475 cm−1) and B2g (775 cm−1), indicating that the grown SnO2 belongs to the rutile structure. The first‐order A1g mode is observed as an intense band, whereas the other two modes show low intensity. The full width at half‐maximum and band area of the Raman lines of SnO2 nanoparticle annealed at various temperatures were calculated. The effect of high‐temperature annealing on the vibrational modes of SnO2 was studied. The optical image of SnO2 nanocrystalline material was used to understand the surface morphology effect. Copyright © 2011 John Wiley & Sons, Ltd.
High‐pressure studies of the micro‐Raman spectra of iron cyanide complexes: Prussian blue (Fe4[Fe(CN)6]3), potassium ferricyanide (K3[Fe(CN)6]), and sodium nitroprusside (Na2[Fe(CN)5(NO)]·2H2O)
Authors: Barsan Mirela M. , Butler Ian S. , Fitzpatrick Jessica , Gilson Denis F. R.
Published: April 2011

The pressure dependences of the peaks observed in the micro‐Raman spectra of Prussian blue (Fe4[Fe(CN)6]3), potassium ferricyanide (K3[Fe(CN)6]), and sodium nitroprusside (Na2[Fe(CN)5(NO)]·2H2O) have been measured up to 5.0 GPa. The vibrational modes of Prussian blue appearing at 201 and 365 cm−1 show negative dν/dP values and Grüneisen parameters and are assigned to the transverse bending modes of the FeCNFe linkage which can contribute to a negative thermal expansion behavior. A phase transition occurring between 2.0 and 2.8 GPa in potassium ferricyanide is shown by changes in the spectral region 150–700 cm−1. In the spectra of the nitroprusside ion, there are strong interactions between the FeN stretching mode and the FeNO bending and the axial CN stretching modes. The pressure dependence of the NO stretching vibration is positive, 5.6 cm−1 GPa−1, in contrast to the negative behavior in the iron(II)‐meso‐tetraphenyl porphyrinate complex. Copyright © 2011 John Wiley & Sons, Ltd.
Surface‐enhanced Raman spectroscopy of genomic DNA from in vitro grown plant species
Authors: Muntean C. M. , Leopold N. , Halmagyi A. , Valimareanu S.
Published: April 2011

Surface‐enhanced Raman scattering (SERS) effect was used to demonstrate ultrasensitive optical detection of nucleic acids. In this work, the SERS spectra of seven genomic DNAs from leaves of Arnica montana (L.), Fam. Compositae, Astragalus peterfii (Jáv.), Fam. Fabaceae, Kalanchoe x hybrida, Fam. Crassulaceae, strawberry (Fragaria x ananassa Duch.), Fam. Rosaceae, carnation (Dianthus caryophyllus L.), Fam. Caryophyllaceae, apple (Malus domestica Borkh.), Fam. Rosaceae and Persian violet (Exacum affine Balf.), Fam. Gentianaceae were analyzed in the wavenumber range 200–1800 cm−1. SERS signatures, spectroscopic band assignments and structural interpretations of these plant genomic DNAs are reported. SERS spectra of nucleic acids are compared here with caution, because these signals are time‐dependent. The SERS spectra corresponding to DNA from Arnica, Dianthus, Fragaria and Kalanchoe leaves show well‐resolved, accurate bands, providing thus a high molecular structural information content. Based on this work, specific plant DNA–ligand interactions or DNA structural changes induced by plant stress conditions associated with their natural environment might be further investigated using SERS spectroscopy. Besides, this study will generate information that is valuable in the development of label‐free DNA‐based nanosensors for chemical probing in the living cell. Copyright © 2011 John Wiley & Sons, Ltd.
Comparison of chemometric methods in the analysis of pharmaceuticals with hyperspectral Raman imaging
Authors: Vajna Balázs , Patyi Gergö , Nagy Zsombor , Bódis Attila , Farkas Attila , Marosi György
Published: April 2011

Chemical imaging method of vibrational spectroscopy, which provides both spectral and spatial information, creates a three‐dimensional (3D) dataset with a huge amount of data. When the components of the sample are unknown or their reference spectra are not available, the classical least squares (CLS) method cannot be applied to create visualized distribution maps. Raman image datasets can be evaluated even in such cases using multivariate (chemometric) methods for extracting the needed hidden information. The capability of chemometrics‐assisted Raman mapping is evaluated through the analysis of pharmaceutical tablets (considered as unknown) with the aim of estimating the pure component spectra based on the collected Raman image. Six chemometric methods, namely, principal component analysis (PCA), maximum autocorrelation factors (MAF), sample–sample 2D correlation spectroscopy (SS2D), self‐modeling mixture analysis (SMMA), multivariate curve resolution–alternating least squares (MCR‐ALS), and positive matrix factorization (PMF), were compared. SMMA was found to be the best choice to determine the number of components. MCR‐ALS and PMF provided the pure component spectra with the highest quality. MCR‐ALS was found to be superior to PMF in the estimation of Raman scores (which correspond to the concentrations) and yielded almost the same results as CLS (using the real reference spectra). Thus, the combination of Raman mapping and chemometrics could be successfully used to characterize unknown pharmaceuticals, identify their ingredients, and obtain information about their structures. This may be useful in the struggles against illegal and counterfeit products and also in the field of pharmaceutical industry when contaminants are to be identified. Copyright © 2011 John Wiley & Sons, Ltd.
Effects of E‐cadherin (CDH1) gene promoter polymorphisms on the risk and clinicopathological development of hepatocellular carcinoma
Authors: Chien Ming‐Hsien , Yeh Kun‐Tu , Li Yi‐Ching , Hsieh Yi‐Hsien , Lin Chien‐Huang , Weng Meng‐Shih , Kuo Wu‐Hsien , Yang Shun‐Fa
Published: April 2011

Background and Objectives

Hepatocellular carcinoma (HCC) is one of the most frequent malignant neoplasms worldwide, and is the second leading cause of cancer death in Taiwan. E‐cadherin is an epithelial cell adhesion molecule, and decreased E‐cadherin expression in HCC is associated with a poor prognosis. This study investigates the effects of single nucleotide polymorphisms (SNPs) in the E‐cadherin/CDH1 gene promoter on the risk and clinicopathological characteristics of HCC

Methods

131 HCC patients and 347 controls were recruited for this study. Genetic polymorphisms of CDH1‐160 and ‐347 were analyzed by PCR‐RFLP genotyping analysis.

Results

After adjusting for other confounders, results show that individuals with the CDH1‐347G/GA or GA/GA polymorphic genotypes had a significantly higher risk of developing HCC than those with the wild‐type (G/G) genotype (adjusted odds ratio = 2.477; 95%CI: 1.421–4.319). Furthermore, patients with HCC with at least one mutant A allele of CDH1‐160 had a 4.031‐fold risk of progressing to stage III or IV.

Conclusions

This study shows that SNPs in CDH1‐347 gene are associated with an increased risk of HCC, and at least one mutant A allele of CDH1‐160 gene is associated with the development of stage III or IV of HCC in Taiwanese. J. Surg. Oncol. 2011; 104:299–304. © 2011 Wiley‐Liss, Inc.