bluuebunny/crossref_metadata_2025 huggingface dataset:
Rational Construction of Perylene Bisimide Columnar Superstructures with a Biased Helical Sense
Authors: Seki Tomohiro , Asano Atsushi , Seki Shu , Kikkawa Yoshihiro , Murayama Haruno , Karatsu Takashi , Kitamura Akihide , Yagai Shiki
Published: March 2011

Discotic supramolecular complexes bearing six perylene bisimide (PBI) chromophores were prepared by mixing monotopically triple‐hydrogen‐bonding melamines equipped with two PBI chromophores and two 3,7‐dimethyloctyl chiral handles with tritopically triple‐hydrogen‐bonding cyanuric acid (CA). UV/Vis and fluorescence titration experiments demonstrated that the discotic complexes were formed in methylcyclohexane by the 3:1 complexation between the melamines and CA. TEM and AFM studies revealed that the complexes hierarchically organize into fibrous columnar assemblies, which eventually results in the formation of organogels. Circular dichroism (CD) and flash‐photolysis time resolved microwave conductivity measurements revealed the presence of extended chiral stacks of PBI chromophores within the columns. The anisotropy factors of the columnar assemblies are remarkably high (g=1.5×10−3) when considering the presence of only one 3,7‐dimethyloctyl chiral handle per perylene chromophore, suggesting that the columnar structures have a biased helical sense. The fact that the chiral centers are located inside the discotic complexes rather than at their peripheries might be unique structural property responsible for the rather strong optical activities for the assemblies of this chromophore. The effective transcription of the molecular chirality to the extended columnar assemblies through the formation of unique discotic complexes enables the expression of “majority‐rules” chiral amplification effect, which is unprecedented for the supramolecular assemblies of PBIs.
Extension of a quartic equation of state to pure polar fluids
Authors: Zang Lian‐yun , Zhu Qing‐li , Yun Zhi
Published: March 2011

A new approach of calculating the parameters of a quartic equation of state (EOS) (Yun et al., Fluid Phase Equilibria 187‐188, 275‐298 (2001)) was suggested. The parameters of the EOS were correlated to critical constants as well as dipole moment. And the modified quartic EOS was extended to both polar and non‐polar substances without any substance‐dependent empirical constants which are necessary in the original quartic EOS in calculations of polar substances. To validate the new approach, a list of substances, including polar and non‐polar ones, were calculated. The calculated results of both thermodynamic and volumetric properties were obtained with good accuracy.

Une nouvelle approche de calcul des paramètres de l'équation quartique d'état (EQE) a été proposée (Z. Yun et coll., «A new quartic equation of state» Fluid Phase Equilibria. 187–188, 275–298 (2001)). Les paramètres de l'équation d'état ont été mis en corrélation avec les constantes critiques et le moment dipolaire. Les EQE modifiées ont été étendues aux substances polaires et non polaires sans les constantes empiriques inhérentes aux substances, qui sont nécessaires dans les EQE originales de calcul des substances polaires. Afin de valider cette nouvelle approche, plusieurs substances polaires et non polaires ont été calculées. Les résultats obtenus pour les propriétés thermodynamiques et volumétriques étaient d'une bonne précision. © 2011 Canadian Society for Chemical Engineering
Turbulent heat and mass transfer from stationary particles
Authors: Pasternak I. S. , Gauvin W. H.
Published: March 2011

Convective heat and mass transfer rates for 20 shapes suspended in various orientations in a hot turbulent air stream were correlated by the equation:

for turbulent intensities between 9 and 10%, using a new characteristic dimension,L”, in the Reynolds Number. This dimension, defined as the total surface area divided by the maximum perimeter perpendicular to flow, was qualitatively explained from boundary layer considerations and was found to correlate the data for different shapes available in the literature. Qualitative pictures for the relative rates of heat and mass transfer around the various shapes were also obtained.
The effect of temperature on the fluidization of silver powders
Authors: Echigoya E. , Osberg G. L.
Published: March 2011

Fluidization tests on pure silver and silver catalyst powder show that agglomeration occurs when the bed is heated, which finally results in bed collapse at a comparatively low temperature. If the bed temperature is held constant in the agglomerating temperature range, an induction period is observed before fluidization ceases. A study of the induction period as a function of temperature (10–60°C.) leads to an activation energy of 18 kcal. for the overall agglomeration process for pure silver. Agglomeration is believed to be due to sintering.
A method for the determination of tie‐lines in ternary liquid systems
Authors: Heric E. L. , Rutledge Ronald M.
Published: March 2011

A method is described for the determination of tie‐lines in ternary liquid systems which may be used when a satisfactory method of chemical analysis is unavailable. The technique is graphical and is based upon the lever rule principle. The method is illustrated with the system acetic acid‐furfural‐water at 25 ± 0.05°. Results indicate the method is accurate and capable of good precision.
Coprecipitation with Cu(II)‐4‐(2‐Pyridylazo)‐resorcinol for Separation and Preconcentration of Fe(III) and Ni(II) in Water and Food Samples
Authors: Tokalıoğlu Şerife , Daşdelen Osman
Published: March 2011

The coprecipitation method is widely used for the preconcentration of trace metal ions prior to their determination by flame atomic absorption spectrometry (FAAS). A simple and sensitive method based on coprecipitation of Fe(III) and Ni(II) ions with Cu(II)‐4‐(2‐pyridylazo)‐resorcinol was developed. The analytical parameters including pH, amount of copper (II), amount of reagent, sample volume, etc., were examined. It was found that the metal ions studied were quantitatively coprecipitated in the pH range of 5.0–6.5. The detection limits (DL) (n = 10, 3s/b) were found to be 0.68 µg L−1 for Fe(III) and 0.43 µg L−1 for Ni(II) and the relative standard deviations (RSD) were ≤4.0%. The proposed method was validated by the analysis of three certified reference materials (TMDA 54.4 fortified lake water, SRM 1568a rice flour, and GBW07605 tea) and recovery tests. The method was successfully applied to sea water, lake water, and various food samples.
Discovering Small‐Molecule Estrogen Receptor α/Coactivator Binding Inhibitors: High‐Throughput Screening, Ligand Development, and Models for Enhanced Potency
Authors: Sun Aiming , Moore Terry W. , Gunther Jillian R. , Kim Mi‐Sun , Rhoden Eric , Du Yuhong , Fu Haian , Snyder James P. , Katzenellenbogen John A.
Published: March 2011

Small molecules, namely coactivator binding inhibitors (CBIs), that block estrogen signaling by directly inhibiting the interaction of the estrogen receptor (ER) with coactivator proteins act in a fundamentally different way to traditional antagonists, which displace the endogenous ligand estradiol. To complement our prior efforts at CBI discovery by de novo design, we used high‐throughput screening (HTS) to identify CBIs of novel structure and subsequently investigated two HTS hits by analogue synthesis, finding many compounds with low micromolar potencies in cell‐based reporter gene assays. We examined structure–activity trends in both series, using induced‐fit computational docking to propose binding poses for these molecules in the coactivator binding groove. Analysis of the structure of the ER–steroid receptor coactivator (SRC) complex suggests that all four hydrophobic residues within the SRC nuclear receptor box sequence are important binding elements. Thus, insufficient water displacement upon binding of the smaller CBIs in the expansive complexation site may be limiting the potency of the compounds in these series, which suggests that higher potency CBIs might be found by screening compound libraries enriched with larger molecules.
Design, Synthesis, and Pharmacological Characterization of Novel Spirocyclic Quinuclidinyl‐Δ2‐Isoxazoline Derivatives as Potent and Selective Agonists of α7 Nicotinic Acetylcholine Receptors
Authors: Dallanoce Clelia , Magrone Pietro , Matera Carlo , Frigerio Fabio , Grazioso Giovanni , De Amici Marco , Fucile Sergio , Piccari Vanessa , Frydenvang Karla , Pucci Luca , Gotti Cecilia , Clementi Francesco , De Micheli Carlo
Published: March 2011

A set of racemic spirocyclic quinuclidinyl‐Δ2‐isoxazoline derivatives was synthesized using a 1,3‐dipolar cycloaddition‐based approach. Target compounds were assayed for binding affinity toward rat neuronal homomeric (α7) and heteromeric (α4β2) nicotinic acetylcholine receptors. Δ2‐Isoxazolines 3 a (3‐Br), 6 a (3‐OMe), 5 a (3‐Ph), 8 a (3‐OnPr), and 4 a (3‐Me) were the ligands with the highest affinity for the α7 subtype (Ki values equal to 13.5, 14.2, 25.0, 71.6, and 96.2 nM, respectively), and showed excellent α7 versus α4β2 subtype selectivity. These compounds, tested in electrophysiological experiments against human α7 and α4β2 receptors stably expressed in cell lines, behaved as partial α7 agonists with varying levels of potency. The two enantiomers of (±)‐3‐methoxy‐1‐oxa‐2,7‐diaza‐7,10‐ethanospiro[4.5]dec‐2‐ene sesquifumarate 6 a were prepared using (+)‐dibenzoyl‐L‐ or (−)‐dibenzoyl‐D‐tartaric acid as resolving agents. Enantiomer (R)‐(−)‐6 a was found to be the eutomer, with Ki values of 4.6 and 48.7 nM against rat and human α7 receptors, respectively.
Effectiveness of alternating mammography and magnetic resonance imaging for screening women with deleterious BRCA mutations at high risk of breast cancer
Authors: Le‐Petross Huong T. , Whitman Gary J. , Atchley Deanne P. , Yuan Ying , Gutierrez‐Barrera Angelica , Hortobagyi Gabriel N. , Litton Jennifer K. , Arun Banu K.
Published: March 2011

BACKGROUND:

Magnetic resonance imaging (MRI) has been used to supplement screening mammography and clinical breast examination (CBE) in women who are at high risk of developing breast cancer. In this study, the authors investigated the efficacy of alternating screening mammography and breast MRI every 6 months in women who had a genetically high risk of developing breast cancer.

METHODS:

A retrospective chart review was performed on all women who were seen in a high‐risk breast cancer clinic from 1997 to 2009. Patients with breast cancer gene (BRCA) mutations who underwent alternating screening mammography and breast MRI every 6 months were included in the study. Mammography, ultrasonography, MRI, and biopsy results were reviewed.

RESULTS:

Of 73 patients who met the study criteria, 37 had BRCA1 mutations, and 36 had BRCA2 mutations. Twenty‐one patients (29%) completed 1 cycle of mammography and MRI surveillance, 23 patients (31%) completed 2 cycles, 18 patients (25%) completed 3 cycles, and patients 11 (15%) completed ≥4 cycles. The median follow‐up was 2 years (range, 1‐6 years). Thirteen cancers were detected among 11 women (15%). The mean tumor size was 14 mm (range, 1‐30 mm), and 2 patients had bilateral cancers. Twelve of 13 cancers were detected on an MRI but not on the screening mammography study that was obtained 6 months earlier. One cancer (a 1‐mm focus of ductal carcinoma in situ) was an incidental finding in a prophylactic mastectomy specimen. One patient had ipsilateral axillary lymphadenopathy identified on ultrasonography but had no evidence of lymph node involvement after neoadjuvant chemotherapy and surgery.

CONCLUSIONS:

In women who were at genetically high risk of developing breast cancer, MRI detected cancers that were not identified on mammography 6 months earlier. Future prospective studies are needed to evaluate the benefits of this screening regimen. Cancer 2011;. © 2011 American Cancer Society.
Turning conventional wisdom upside‐down
Authors: Morgentaler Abraham
Published: March 2011

A revolution in traditional oncological concepts has shifted our gaze from high serum testosterone to low testosterone as a potential predictor of high‐risk prostate cancer. The results of a study by Salonia et al add to a growing literature indicating that preoperative low serum T increases the likelihood of high‐risk prostate cancer.
Assessing the impact of comorbid illnesses on death within 10 years in prostate cancer treatment candidates
Authors: Alibhai Shabbir M. H.
Published: March 2011

Groome et al use the case‐cohort design to study the contribution of comorbidity to death from causes other than prostate cancer in a large group of men treated for cure. They modify an existing comorbidity instrument, the CIRS‐G, for use to predict risk of dying from nonprostate cancer causes.
Enhanced Catalytic Activity of Sub‐nanometer Titania Clusters Confined inside Double‐Wall Carbon Nanotubes
Authors: Zhang Hongbo , Pan Xiulian , Liu Jingyue (Jimmy) , Qian Weizhong , Wei Fei , Huang Yuying , Bao Xinhe
Published: March 2011

Sub‐nanometer titania clusters have been homogeneously dispersed within double‐wall carbon nantubes (DWNTs) with an inner diameter ranging from 1.0 to 1.5 nm. The confined titania exhibits a much higher activity than the titania particles attached on the outside walls of the DWNTs (the outside titania) in the epoxidation of propylene by H2O2. XPS, XANES and Raman spectroscopy data suggest electron transfer from titanium to the inner surfaces of the DWNTs. In contrast, no electron transfer has been observed for the outside titania. We also found that the extent of this confinement‐induced electron transfer is temperature dependent. The enhanced activity of the confined titania clusters is likely attributed to their small sizes and the interaction with the DWNT surface. The synthesis method that we developed here can be readily applied to incorporation of other metal/metal oxide nanoparticles into carbon nanotubes.
Multistage multiphase switched‐capacitor DC–DC converter with variable‐phase and PWM control
Authors: Chang Yuen‐Haw , Chen Yi‐Ching
Published: March 2011

A closed‐loop multistage multiphase switched‐capacitor converter (n‐stagep‐phase MPSC) is proposed with a variable‐phase control (VPC) and a pulse‐width‐modulation (PWM) technique for low‐power step‐up conversion and high‐efficiency regulation. In thisn‐stage MPSC,nvoltage doublers are connected in series for boosting the voltage gain up to 2nat most. Here, VPC is suggested to realize a variable multiphase operation by changing the phase numberpand topological path for the more suitable level of voltage gain so as to improve the power efficiency, especially for the lower output voltage Besides, PWM is adopted not only to enhance output regulation for different desired outputs, but also to reinforce output robustness to source/loading variation. Further, some theoretical analyses and designs include:n‐stagep‐phase MPSC model, steady‐state analysis, conversion ratio, power efficiency, output ripple, stability, capacitance selection, and control design. Finally, the closed‐loop MPSC is simulated, and the hardware is implemented and tested. All the results are illustrated to show the efficacy of the proposed scheme. Copyright © 2011 John Wiley & Sons, Ltd.
Regulation of limb bud initiation and limb‐type morphology
Authors: Duboc Veronique , Logan Malcolm P. O.
Published: March 2011

While the paired forelimb and hindlimb buds of vertebrates are initially morphologically homogeneous, as the limb progenitors differentiate, each individual tissue element attains a characteristic limb‐type morphology that ultimately defines the constitution of the forelimb or hindlimb. This review focuses on contemporary understanding of the regulation of limb bud initiation and formation of limb‐type specific morphologies and how these regulatory mechanisms evolved in vertebrates. We also attempt to clarify the definition of the terms limb‐type identity and limb‐type morphology that have frequently been used interchangeably. Over the last decade, three genes, Tbx4, Tbx5, and Pitx1, have been extensively studied for their roles in limb initiation and determining limb‐type morphologies. The role of Tbx4 and Tbx5 in limb initiation is clearly established. However, their putative role in the generation of limb‐type morphologies remains controversial. In contrast, all evidence supports a function for Pitx1 in determination of hindlimb morphologies. Developmental Dynamics 240:1017–1027, 2011. © 2011 Wiley‐Liss, Inc.
Regulation of leg size and shape: Involvement of the Dachsous‐fat signaling pathway
Authors: Bando Tetsuya , Mito Taro , Nakamura Taro , Ohuchi Hideyo , Noji Sumihare
Published: March 2011

How limb size and shape is regulated is a long‐standing question in developmental and regeneration biology. Recently, the protocadherin Dachsous‐Fat (Ds‐Ft) signaling pathway has been found to be essential for wing development of the fly and leg regeneration of the cricket. The Ds‐Ft signaling pathway is linked to the Warts‐Hippo (Wts‐Hpo) signaling pathway, leading to cell proliferation. Several lines of evidence have suggested that the Wts‐Hpo signaling pathway is involved in the control of organ size, and that this pathway is regulated by Ds‐Ft and Merlin‐Expanded, which are linked to morphogens such as decapentaplegic/bone morphogenic protein, Wingless/Wnt, and epidermal growth factor. Here we review recent progress in elucidating mechanisms controlling leg size and shape in insects and vertebrates, focusing on the Ds‐Ft signaling pathway. We also introduce a working model, Ds‐Ft steepness model, to explain how steepness of the Ds‐Ft gradient controls leg size along the proximodistal axis. Developmental Dynamics 240:1028–1041, 2011. © 2011 Wiley‐Liss, Inc.
Synthesis and Some Chemical Properties of a 1,2λ3σ3‐Thiaphosphirane
Authors: Turcheniuk Kostiantyn V. , Rozhenko Alexander B. , Shevchenko Igor V.
Published: March 2011

A rare example of the addition of sulfur to a phosphaalkene double bond leading to 1,2λ3,σ3‐thiaphosphirane 4 is described. The relative accessibility of this compound has allowed the study of some of the chemical properties of the thiaphosphirane ring. The thermodynamic stability of 1,2λ3,σ3‐thiaphosphiranes compared with λ5,σ3‐phosphoranes has been studied by DFT calculations.
Synthesis and Reactivity of New Pyrazolyl‐Functionalized Potassium Silanides
Authors: McNerney Brian , Whittlesey Bruce , Krempner Clemens
Published: March 2011

The pyrazolyl‐functionalized oligosilanes Si(SiMe2PzR)4 (2a R = tBu; 2b R = iPr) were prepared by the reaction of 3‐R‐pyrazole (R = iPr, tBu) with Si(SiMe2Cl)4 in the presence of NEt3. By treatment with tBuOK and 18‐crown‐6 in THF, 2a, b were converted into the new potassium silanides (PzRMe2Si)3SiK(18‐crown‐6) (3a R = tBu; 3b R = iPr), respectively. Upon adding W(CO)6 to THF solutions of 3a, b the tungsten complexes [(PzRMe2Si)3SiW(CO)5]K(18‐crown‐6) (4a R = tBu; 4b R = iPr) were readily formed, whereas upon adding MgBr2 fragmentation occurs leading to the formation of [(PzRMe2Si)2Si‐SiMe2]2 5.
Unusual Expansion of the 1,2,4,5‐Tetrazine Ring in [1,2,4]Triazolo[4,3‐b][1,2,4,5]tetrazines Leading to [1,2,4,6]Tetrazepine Systems
Authors: Ganebnykh Ilya N. , Tolshchina Svetlana G. , Ishmetova Rashida I. , Ignatenko Nina K. , Slepukhin Pavel A. , Rusinov Gennady L. , Charushin Valery N.
Published: March 2011

Expansion of the tetrazine ring has first been found to occur when [1,2,4]triazolo[4,3‐b][1,2,4,5]tetrazines were allowed to react with CH‐active compounds in acetonitrile in the presence of triethylamine to give the unexpected series of 8,9‐dihydro‐7H‐[1,2,4]‐triazolo[4,3‐b][1,2,4,6]tetrazepine derivatives.
Orthogonal Synthesis of Fluorinated Acridones and Acridines from Perfluorobenzophenone
Authors: Del Buttero Paola , Gironda Ramona , Moret Massimo , Papagni Antonio , Parravicini Matteo , Rizzato Silvia , Miozzo Luciano
Published: March 2011

The reaction between perfluorobenzophenone and aromatic amines proceeds with the substitution of one or more fluorine atoms. The regiochemistry of this substitution is controlled by solvent polarity, temperature, and nucleophilic character of the amine. o‐Anilinononafluorobenzophenone can be selectively transformed into acridines or acridones by using acid or base catalysis through electrocyclization or aromatic nucleophilic substitution.
A Facile One‐Pot Access to Dibenzo[b,e]oxepines by a Lewis Acid Catalysed Tandem Reaction
Authors: Reddy Chada R. , Ramesh Palacherla , Rao Nagavaram N. , Ali Saiyed A.
Published: March 2011

Dibenzo[b,e]oxepine derivatives have been constructed efficiently by one‐pot tandem carbon–carbon bond formation reactions. First, 2‐(3,5‐dimethoxybenzyloxy)benzaldehydes were treated with various nucleophiles under I2 catalysis and then 1‐(3,5‐dimethoxybenzyloxy)‐3,5‐dimethoxybenzene was treated with several aromatic as well as heteroaromatic aldehydes under BF3·Et2O catalytic conditions to provide dibenzo[b,e]oxepines in good yields.
An Impedimetric Glucose Biosensor Based on Overoxidized Polypyrrole Thin Film
Authors: Zane D. , Appetecchi G. B. , Bianchini C. , Passerini S. , Curulli A.
Published: March 2011

Polypyrrole (pPy) thin films were synthesized electrochemically by a pulse method on platinum electrodes in N‐butyl‐N‐methyl‐pyrrolidinium bis(trifluoromethanesulfonyl)imide ionic liquid (PYR14TFSI). An important aspect of this procedure is the use of an ionic liquid, as synthetic medium. Further, it can be used for several procedures and it can then be renewed and recycled by a simple extraction just with warm water. It is therefore possible to remove it from all the residual oxidized pyrrolic compounds and purify the solvent in a very simplicistic way. After the synthesis pPy was overoxidized (opPy ) and the process was followed by EIS (Electrochemical Impedance Spectroscopy). opPy is attractive for the realization of sensors and biosensors because of its good selectivity towards hydrogen peroxide (H2O2) with respect to the most common interferents. In particular it can find an application in food process control. The EIS response to hydrogen peroxide and biological interferents indicated opPy as a highly sensitive electrochemical platform for impedimetric sensing. The glucose oxidase enzyme (GOD) was immobilized onto the polymer and the modified electrode was assembled and tested as an impedimetric biosensor. This technique seems very promising for application in food process control.
Direct Electrochemistry and Electrocatalysis of Horseradish Peroxidase Immobilized on Water Soluble Sulfonated Graphene Film via Self‐assembly
Authors: Zhang Qian , Qiao Yun , Zhang Ling , Wu Shuyao , Zhou Hua , Xu Jingwei , Song Xi‐Ming
Published: March 2011

A novel water soluble sulfonated graphene (denoted as sulfonated‐G), was synthesized for the immobilization and biosensing of horseradish peroxidase (HRP). Compared with unmodified graphene, sulfonated‐G could not only well disperse in aqueous solution as individual nanosheet, but also exhibit apparent negative charge. Using a simple self‐assembly method, HRP was immobilized on sulfonated‐G at the surface of GC electrode to form HRP/sulfonated‐G/GC electrode under mild condition. The immobilized HRP showed enhanced direct electron transfer for the HRP‐Fe(III)/Fe(II) redox centre. Based on the direct electron transfer of the immobilized HRP, HRP/sulfonated‐G/GC electrode exhibited excellent catalytic performance for H2O2 and NaNO2 reduction. Accordingly, the proposed method not only simplifies the methodology of enzyme immobilization, but also provides an efficient platform for fabricating novel biosensors and bioelectronic devices.
Experimental and PM6/SPARKLE Semiempirical Study of Interaction between 4‐Methoxyphenylcyanamide and Gadolinium(III) as a Fast Polymeric Membrane Sensor
Authors: Rezaei Behzad , Askarpour Neda , Hadadzadeh Hassan
Published: March 2011

In this study, a highly sensitive PVC–membrane sensor based on 4‐methoxyphenylcyanamide (4‐MeOpcyd) as a neutral carrier was prepared and the specific interaction between Gd3+ ions and ionophore at the surface of selective polymeric membrane was calculated using the PM6/SPARKLE semiempirical method. The results of the Mopac2009 calculations show selective complexation of Gd3+ by 4‐MeOpcyd ligand that correlate quite well with experimental data. This membrane sensor has a linear response in the range of 1.0×10−6–1.0×10−2 M Gd3+ with detection limit of 6.2×10−7 M. This electrode was applied in potentiometric titration for determination of gadolinium and also for fluoride ions in the mouthwash samples with satisfactory results.
Development of a Sputtered Nanocarbon Film Based Microdisk Array Electrode for the Highly Stable Detection of Serotonin
Authors: Inokuchi Hiroaki , Kato Dai , Ueda Akio , Niwa Osamu
Published: March 2011

We report a nanocarbon film based microdisk array electrode with an extremely stable electrochemical response for measuring serotonin. The nanocarbon film was formed on a silicon substrate with an electron cyclotron resonance sputtering method, and the nanocarbon film based microdisk array electrode was fabricated using photolithography. The array electrode consists of 335 microdisks with a diameter of 10 µm. The center‐to‐center distance of each microdisk is 100 µm. The electrochemical properties of the nanocarbon film based microdisk array electrode are compared with those of a gold film based array electrode. Before microfabrication, both nanocarbon and gold film electrodes (both 2 mm in diameter) showed steady responses for the continuous voltammetric measurement of 1 µM of serotonin. Moreover, each microdisk array electrode exhibited a sigmoidal response. The obtained current densities were higher than those of conventional sized electrodes owing to the microelectrode effect. However, the current value at 0.45 V vs. Ag/AgCl at the gold film based microdisk array electrode decreased rapidly and fell to 30 % of its initial value after ten potential scans. In contrast, the nanocarbon film based microdisk array electrode decreased only 2 % under the same measurement condition. Despite the fact that there was more than 10 times the current density at the microelectrode, our nanocarbon film showed excellent performance in suppressing serotonin adsorption.
An empirical pseudo‐Bayes approach to determining a weighted‐summation for use in generalized linear models
Authors: Sabo Roy T.
Published: March 2011

Studies have consistently shown that exposure to certain pesticides can be linked to adverse health conditions in both children and adults. These effects are complicated by exposure to multiple pesticides in the form of a chemical mixture. In this manuscript a methodology is presented that simultaneously summarizes the exposure profile into a representative value, yet maintains information on the individual constituents. An empirical Pseudo‐Bayes (EB) approach is used to create a weighted‐summation of the chemical concentrations, where Monte‐Carlo methods are used to derive the weights from prior distributions based on information from the univariate relationships between each chemical and some response. This weighted summation is used to estimate a relationship between the set of chemicals and the response. A simulation study is used to compare the EB approach with two traditional approaches used in chemical exposure risk assessment, and an example is provided using pesticide data and metabolic hormone concentrations from the National Health and Nutrition Examination Survey. Copyright © 2011 John Wiley & Sons, Ltd.
Trafficking and secretion of matrix metalloproteinase‐2 in olfactory ensheathing glial cells: A role in cell migration?
Authors: Gueye Yatma , Ferhat Lotfi , Sbai Oualid , Bianco John , Ould‐Yahoui Adlane , Bernard Anne , Charrat Eliane , Chauvin Jean‐Paul , Risso Jean‐Jacques , Féron François , Rivera Santiago , Khrestchatisky Michel
Published: March 2011

Olfactory ensheathing cells (OECs) are unique glia found only in the olfactory system. They retain exceptional plasticity and support olfactory neurogenesis and retargeting across the PNS:CNS boundary in the olfactory system. OECs have been shown to improve functional outcome when transplanted into rodents with spinal cord injury. The growth‐promoting properties of implanted OECs encompass their ability to migrate through the scar tissue and render it more permissive for axonal outgrowth, but the underlying molecular mechanisms remain poorly understood. OECs appear to regulate molecules of the extracellular matrix (ECM) that inhibit axonal growth. Among the proteins that have the potential to promote cell migration, axonal regeneration and remodeling of the ECM are matrix metalloproteinases (MMPs), a family of endopeptidases that cleave matrix, soluble, and membrane‐bound proteins and that are regulated by their endogenous inhibitors, the tissue inhibitors of MMPs (TIMPs). Little is known about MMP/TIMP trafficking, secretion, and role in OECs. Using a combination of cell biology, biochemistry, pharmacology, and imaging techniques, we show that MMP‐2 and MMP‐9 are expressed and proteolytically active in the olfactory epithelium and in particular in the OECs of the lamina propria. These proteinases and regulatory proteins such as MT1‐MMP and TIMP‐2 are expressed in cultured OECs. MMPs exhibit nuclear localization and vesicular trafficking and secretion, with distribution along microtubules and microfilaments and co‐localization with the molecular motor protein kinesin. Finally, we show that MMPs are involved in migration of OECs in vitro on different ECM substrates. © 2011 Wiley‐Liss, Inc.
GDNF‐induced osteopontin from Müller glial cells promotes photoreceptor survival in the Pde6brd1 mouse model of retinal degeneration
Authors: Del Río Patricia , Irmler Martin , Arango‐González Blanca , Favor Jack , Bobe Caroline , Bartsch Udo , Vecino Elena , Beckers Johannes , Hauck Stefanie M. , Ueffing Marius
Published: March 2011

Glial cell line‐derived neurotrophic factor (GDNF) enhances the survival of a variety of neurons, including photoreceptors (PR) in the retina. In contrast to most other GDNF receptive neurons, GDNF does, however, not exert its neuroprotective activity directly on PR neurons but transmits it indirectly by inducing expression of yet unknown neurotrophic factors in retinal Müller glial (RMG) cells. Genome‐wide differential transcriptome analyses of GDNF‐treated mouse retinas revealed 30 GDNF‐induced transcripts containing a total of six genes coding for secreted molecules. Among them was (OPN), a secreted glycoprotein which was expressed in mouse RMG and secreted from primary mouse RMG in culture. Furthermore, OPN secretion was significantly upregulated on GDNF treatment of primary RMG. To validate, whether OPN could qualify as a neuroprotective factor for PR, we evaluated its potential neurotrophic activity on isolated PR in vitro as well as on retinal explants from the retinal degeneration 1 (Pde6brd1) mouse mutant. OPN exerted a significant, positive survival effect on primary porcine PR cells in a concentration‐dependent manner and induced activation of PI3K/Akt pro‐survival pathway. Moreover, in retinal explant cultures from Pde6brd1 mice, OPN significantly reduced the percentage of apoptotic cells to levels comparable with that observed in explants from wild‐type mice and led to survival of significantly more PR in long‐term retinal explant cultures. Our findings suggest that RMG‐derived OPN is a novel candidate protein that transmits part of the GDNF‐induced neuroprotective activity of RMG to PR cells. © 2011 Wiley‐Liss, Inc.
Depression symptom ratings in geriatric patients with bipolar mania
Authors: Sajatovic Martha , Jurdi Rayan Al , Gildengers Ariel , Greenberg Rebecca L. , Tenhave Thomas , Bruce Martha L. , Mulsant Benoit , Young Robert C.
Published: March 2011

Objective

Given the paucity of information available regarding standardized ratings of depression symptoms in bipolar manic states, and in particular those in older adults, we explored depression ratings in symptomatic participants in a multicenter study of treatment of bipolar I disorder in late life.

Methods

Baseline data was obtained from the first 100 patients enrolled in an NIMH‐funded, 9‐week, randomized, double‐blind RCT comparing treatment with lithium or valproate in patients of age 60 years and older with Type I Bipolar mania or hypomania. This multi‐site study was conducted at six academic medical centers in the United States and enrolled inpatients and outpatients with a total Young Mania Rating Scale (YMRS) score of 18 or greater. Depressive symptoms were evaluated with the Hamilton Depression Rating Scale (HAM‐D) and the Montgomery‐Asberg Depression Rating Scale (MADRS). The criterion for at least moderate bipolar depressive symptoms was the European College of Neuropsychopharmacology (ECNP) Consensus Meeting definition of HAM‐D 17 total score >20.

Results

Eleven percent of patients had mixed symptoms defined by depression scale severity according to ECNP criterion. In the overall sample, total scores on the two depression scales were highly correlated. Total YMRS scores of this mixed symptom group were similar to the remainder of the sample.

Conclusions

These preliminary findings suggest that moderate to severe depressive symptoms occur in about one in ten bipolar manic elders. Future studies are needed to further evaluate symptom profiles, clinical correlates, and treatments for bipolar older adults with combined manic and depressive symptoms. Copyright © 2011 John Wiley & Sons, Ltd.
Performance variation of an R22 window air conditioner retrofitted with a HFC/HC refrigerant mixture under different ambient conditions over a range of charge quantities
Authors: Herbert Raj M. , Mohan Lal D.
Published: March 2011

R22 has been generally accepted as the most suitable refrigerant for air conditioners, due to its favorable thermodynamic properties. However, R22 is a controlled substance under the Montreal protocol. M20 is a HFC/HC refrigerant mixture that can be used as a substitute for R22. This paper presents experimental investigation on the performance comparison of a window air conditioner operated with the M20 tested under different refrigerant charge levels and outdoor conditions against that with R22. Experiments were conducted in accordance with BIS procedure in a psychrometric test facility. Refrigerant charge in the air conditioner was systematically varied from 900 to 1600 g in steps of 50 g for R22 and 697 to 1279 g in steps of 39 g [equivalent to 50 g of R22] for the M20. At each charge levels, the outdoor room conditions were changed in accordance with BIS standards. It is observed that R22 is more sensitive to deviations in charge levels as compared to the M20. A decrease in charge level of about 7% reduced the system refrigerating capacity by 11.3% with R22 while with the M20 refrigerant mixture it reduces by 6.9% only. Similarly an overcharge by 7% reduces the refrigerating capacity of the system by 13.8% with R22 while with M20 it reduces by 6.5% only. Thus M20 is less sensitive to charge deviations. © 2011 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library (wileyonlinelibrary.com/journal/htj). DOI 10.1002/htj.20339
Analytical and numerical investigation of fin efficiency and temperature distribution of conductive, convective, and radiative straight fins
Authors: Ganji D.D. , Rahimi M. , Rahgoshay M. , Jafari M.
Published: March 2011

In this study, fin efficiency, temperature distribution, and effectiveness of conductive, convective, and radiative straight fins with temperature dependent thermal conductivity are solved using the differential transformation method (DTM).The concept of differential transformation is briefly introduced, and then it is employed to derive the solutions of nonlinear governing equations of fins with highly nonlinear terms because of existing radiation in this study. The obtained results of DTM are compared with those of the Galerkin method (GM) and numerical boundary value problem method (BVP) to verify the accuracy of the proposed method. Furthermore, the effects of some physical appropriate parameters such as thermo‐geometric fin parameters and thermal parameters are analyzed. © 2011 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library (wileyonlinelibrary.com/journal/htj). DOI 10.1002/htj.20341
The effect of estrogen vs. combined estrogen‐progestogen therapy on the risk of colorectal cancer
Authors: Lin Kueiyu Joshua , Cheung Winson Y. , Lai Jennifer Yi‐Chun , Giovannucci Edward L.
Published: March 2011

Studies suggest that estrogen therapy (ET) and combined estrogen‐progestogen therapy (EPT) may have different associations with colorectal cancer (CRC) risk, but data are conflicting. Prior meta‐analyses did not distinguish between ET and EPT. We conducted a meta‐analysis to summarize the relative risks (RR) of CRC due to ET versus EPT among peri‐ or postmenopausal women. From a total of 2,661 articles, four randomized controlled trials, eight cohort and eight case‐control studies were included. Variables assessed included study characteristics, duration and recency of menopausal hormone therapy (HT) use, method of assessment of HT use, outcome definition and its ascertainment method. RRs were synthesized by random‐effects models. We found that EPT ever use was associated with a decreased risk of CRC (RR 0.74, 95% CI 0.68‐0.81), and so was ET ever use (RR 0.79, 95% CI 0.69‐0.91). While current use of ET was associated with a significantly reduced risk of CRC (RR 0.70, 95% CI 0.57‐0.85), former use was not (RR 0.86, 95%CI 0.67‐1.11). Recency did not significantly modify the association between EPT and CRC risk. EPT former use was associated with a lower RR of CRC compared to ET former use (p = 0.008) but no such difference was observed between EPT and ET current use (p = 0.12). Overall, we found consistent evidence supporting the association between EPT and CRC risk reduction, regardless of recency. While literature for the association between ET and CRC risk is heterogeneous, our analyses suggest only current use of ET is associated with a decreased CRC risk.
The impact of amyloid precursor protein signalling and histone deacetylase inhibition on neprilysin expression in human prostate cells
Authors: Hong Yue , Beckett Caroline , Belyaev Nikolai D. , Turner Anthony J.
Published: March 2011

The zinc metallopeptidase, neprilysin (NEP), is an endothelin‐1 degrading enzyme whose expression is extensively downregulated in prostate cancer. The expression of NEP in neuronal cells is regulated by intramembrane proteolysis of the amyloid precursor protein (APP) through its intracellular domain (AICD) facilitating histone acetylation of the NEP promoter and gene transcription. The present study has examined whether similar mechanisms operate in prostate cell lines. The expression of APP and its processing enzymes (β‐ and γ‐secretases) was examined in a number of prostate cell lines, and the effect of γ‐secretase inhibition was explored on NEP expression and activity. The potential interaction of AICD with the NEP promoter was examined by chromatin immunoprecipitation. Our results indicated that all key components involved in APP processing were expressed in prostate cancer cell lines but suppression of AICD production using a γ‐secretase inhibitor did not decrease NEP expression and activity, and no direct AICD‐NEP promoter interaction could be detected. However, histone deacetylase inhibitors (valproate and trichostatin A) caused a 2‐ to 3‐fold increase in NEP expression in PC‐3 cells, and combinatorial treatment with the DNA demethylating agent, AzaC, further increased NEP expression levels. Although AICD is detectable in prostate cell lines, it does not appear to regulate NEP by AICD‐mediated signalling. Apart from promoter de‐methylation, the data suggest that histone acetylation may facilitate partial re‐activation of NEP expression in advanced prostate cancer cells. Upregulation of this tumour‐suppressing protein may provide a novel therapeutic strategy in prostate cancer.
The seed and soil hypothesis revisited—The role of tumor‐stroma interactions in metastasis to different organs
Authors: Langley Robert R. , Fidler Isaiah J.
Published: March 2011

The fact that certain tumors exhibit a predilection for metastasis to specific organs has been recognized for well over a century now. An extensive body of clinical data and experimental research has confirmed Stephen Paget's original “seed and soil” hypothesis that proposed the organ‐preference patterns of tumor metastasis are the product of favorable interactions between metastatic tumor cells (the “seed”) and their organ microenvironment (the “soil”). Indeed, many of the first‐line therapeutic regimens, currently in use for the treatment of human cancer are designed to target cancer cells (such as chemotherapy) and also to modulate the tumor microenvironment (such as antiangiogenic therapy). While some types of tumors are capable of forming metastases in virtually every organ in the body, the most frequent target organs of metastasis are bone, brain, liver and the lung. In this review, we discuss how tumor‐stromal interactions influence metastasis in each of these organs.
The ring current model of the pentaprismane molecule
Authors: Pelloni Stefano , Carion Raphaël , Liégeois Vincent , Lazzeretti Paolo
Published: March 2011

Three‐dimensional models of the quantum‐mechanical current density
JB, induced in the electron cloud of the C10H10 pentaprismane molecule by a magnetic field B
applied along the C5 (a C2) symmetry axis, orthogonal to the pentagonal (a rectangular) face, and denoted by B‖ (B⟂), have been constructed. Predictions of near Hartree‐Fock quality are reported for the diagonal components of magnetic tensors, magnetizability (ξ), nuclear shielding of carbon (σC)
and hydrogen (σH), and virtual shielding at the center of mass (σCM). The complicated spatial features of the induced electronic current‐density field have been rationalized and compactly described via stagnation graphs that elucidate the details of its topological structure. A representation of JB
is obtained by three‐dimensional perspective plots and by planar maps visualizing phase portraits of electron flow in a series of molecular domains. Both streamline JB/|JB|
and modulus |JB|
are analyzed. These graphic tools illustrate the competition between diatropic and paratropic regimes which determine the magnitude of various components of magnetizability and magnetic shielding of hydrogen and carbon nuclei. Shielding density maps show that the differential Biot‐Savart law explains magnetic shielding at hydrogen and carbon nuclei, and virtual shielding at ring and cage centers. Similarities and/or contrasting ring current effects on magnetotropicity are discussed by a comparison with triprismane C6H6 and cubane C8H8. © 2011 Wiley Periodicals, Inc. J Comput Chem , 2011.
Can the transition from tunneling to hopping in molecular junctions be predicted by theoretical calculation?
Authors: Liu Hongmei , Zhao Zhenzhen , Wang Nan , Yu Cui , Zhao Jianwei
Published: March 2011

The electron transport mechanism changes from tunneling to hopping as molecular length increases. To validate the theoretical simulation after the transition point and clarify influence of electronic structures on the transition, we calculated the conductance of a series of conjugated molecules by density functional theory together with the nonequilibrium Green's function. We found that the highest occupied molecular orbital energy level, transmission spectrum, and the reorganization energy are good indicators for the transition of the electron transport mechanism. The calculated resistances of short junctions (<50 Å, before the transition point) are consistent with the experimental result, following the tunneling mechanism. However, the theoretical predication failed for long molecules, indicating the limitation of the theoretical framework of elastic scattering when the electron transport mechanism changes to hopping. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
New ab initio potential energy surfaces for both the ground (X̃1A′) and excited (Ã1A″) electronic states of HSiCl and the absorption and emission spectra of HSiCl/DSiCl
Authors: Lin Sen , Xie Daiqian
Published: March 2011

New ab initio potential energy surfaces for the ground (
$ \tilde X^1 A' $) and excited ($ \tilde A^1 A'' $) electronic states of HSiCl were obtained by using the single and double excitation coupled‐cluster theory with a noniterative perturbation treatment of triple excitations and the multi‐reference configuration interaction with Davidson correction, respectively, employing an augmented correlation‐consistent polarized valence quadruple zeta basis set. For the excited state $ \tilde A^1 A'' $, an extended active space (18 electrons in 12 orbitals) was used. The calculated vibrational energy levels of HSiCl and DSiCl of the ground and excited electronic states are in better agreement with the available experimental values than the previous theoretical results. In addition, with the calculated transition dipole moment, the absorption and emission spectra of HSiCl and DSiCl were calculated using an efficient single Lanczos propagation method and are in reasonable agreement with the available observed spectra. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
Effect of the damping function in dispersion corrected density functional theory
Authors: Grimme Stefan , Ehrlich Stephan , Goerigk Lars
Published: March 2011

It is shown by an extensive benchmark on molecular energy data that the mathematical form of the damping function in DFT‐D methods has only a minor impact on the quality of the results. For 12 different functionals, a standard “zero‐damping” formula and rational damping to finite values for small interatomic distances according to Becke and Johnson (BJ‐damping) has been tested. The same (DFT‐D3) scheme for the computation of the dispersion coefficients is used. The BJ‐damping requires one fit parameter more for each functional (three instead of two) but has the advantage of avoiding repulsive interatomic forces at shorter distances. With BJ‐damping better results for nonbonded distances and more clear effects of intramolecular dispersion in four representative molecular structures are found. For the noncovalently‐bonded structures in the S22 set, both schemes lead to very similar intermolecular distances. For noncovalent interaction energies BJ‐damping performs slightly better but both variants can be recommended in general. The exception to this is Hartree‐Fock that can be recommended only in the BJ‐variant and which is then close to the accuracy of corrected GGAs for non‐covalent interactions. According to the thermodynamic benchmarks BJ‐damping is more accurate especially for medium‐range electron correlation problems and only small and practically insignificant double‐counting effects are observed. It seems to provide a physically correct short‐range behavior of correlation/dispersion even with unmodified standard functionals. In any case, the differences between the two methods are much smaller than the overall dispersion effect and often also smaller than the influence of the underlying density functional. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
On the Role of Extensional Flow in Morphology and Property Modifications of MWCNT/Polyamide‐Based Fibers
Authors: Dintcheva Nadka Tzankova , Arrigo Rossella , Nasillo Giorgio , Caponetti Eugenio , La Mantia Francesco Paolo
Published: March 2011

Unfilled and MWCNT‐filled PA fibers are prepared and the effect of the extensional flow on their mechanical performance and morphological variations is investigated. Morphological analyses using SEM, TEM, and SAXS suggest a stronger orientation of the MWCNTs along the fiber direction with increasing extensional flow. A particular MWCNT bundle formation in the PA drawn nanocomposite fibers is observed for the first time, and a pull‐out of the central nanotube in some bundles is noted. The maintenance of the “shish‐kebab” structure upon extensional flow is responsible for the mechanical improvements and dimensional stability in MWCNT‐filled PA fibers.

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