bluuebunny/crossref_metadata_2025 huggingface dataset:
Cognitive burden of survey questions and response times: A psycholinguistic experiment
Authors: Lenzner Timo , Kaczmirek Lars , Lenzner Alwine
Published: August 2009

An important objective in survey question design is to write clear questions that respondents find easy to understand and to answer. This contribution identifies the factors that influence question clarity. Theoretical and empirical evidence from psycholinguistics suggests that specific text features (e.g., low‐frequency words (LFRWs), left‐embedded syntax) cause comprehension difficulties and impose a high cognitive burden on respondents. To examine the effect of seven different text features on question clarity, an online experiment was conducted in which well‐formulated questions were compared to suboptimal counterparts. The cognitive burden of the questions was assessed with response times. Data quality was compared in terms of drop‐out rates and survey satisficing behaviour. The results show that at least six of the text features are relevant for the clarity of a question. We provide a detailed explanation of these text features and advise survey designers to avoid them when crafting questions. Copyright © 2009 John Wiley & Sons, Ltd.
Social anxiety moderates memory conformity in adolescents
Authors: Wright Daniel B. , London Kamala , Waechter Michael
Published: August 2009

When two people view the same event and later try to remember it together, what one person says affects what the other person reports. A model is presented which predicts that this memory conformity effect will be moderated, in different ways, by two components of social anxiety. People with higher fear of negative evaluation should be more influenced by their peers than others, but those with higher social anxiety related to avoiding social situations may be less influenced by their peers than others. Pairs of adolescent‐aged participants took part in a face recognition study. For each trial one person responded and then the next person responded. The effect of what the first person said on the second person's response was measured; the size of the effect was moderated by the social anxiety measures as predicted by the model. This is the first study showing the relationship between social anxiety and memory suggestibility. Copyright © 2009 John Wiley & Sons, Ltd.
Positive and negative effects of physical context reinstatement on eyewitness recall and identification
Authors: Wong Carol K. , Read J. Don
Published: August 2009

The impact of context reinstatement (CR) on eyewitness recall and identification was explored in this study. Participants viewed a video of a staged theft and, following a 1‐week interval, were asked to identify the culprit and recall the event in either the same or in a different physical environment. Results suggested that CR enhanced the perceived familiarity of the lineup members, which in turn increased participants' willingness to identify someone in the lineup. Although CR significantly improved facial discrimination and identification accuracy when the target was present, it also increased confidence ratings beyond that warranted by the increase in accuracy. In terms of recall, reinstating the study context improved participants' free recall of both central and peripheral details and cued recall of peripheral details. The results were consistent with a (mis)attribution of familiarity and the outshining hypothesis. Copyright © 2009 John Wiley & Sons, Ltd.
Can fabricated evidence induce false eyewitness testimony?
Authors: Wade Kimberley A. , Green Sarah L. , Nash Robert A.
Published: August 2009

False information can influence people's beliefs and memories. But can fabricated evidence induce individuals to accuse another person of doing something they never did? We examined whether exposure to a fabricated video could produce false eyewitness testimony. Subjects completed a gambling task alongside a confederate subject, and later we falsely told subjects that their partner had cheated on the task. Some subjects viewed a digitally manipulated video of their partner cheating; some were told that video evidence of the cheating exists; and others were not told anything about video evidence. Subjects were asked to sign a statement confirming that they witnessed the incident and that their corroboration could be used in disciplinary action against the accused. See‐video subjects were three times more likely to sign the statement than Told‐video and Control subjects. Fabricated evidence may, indeed, produce false eyewitness testimony; we discuss probable cognitive mechanisms. Copyright © 2009 John Wiley & Sons, Ltd.
Modeling of the catalytic removal of CO and NO in dry combustion gases
Authors: Treviño C. , Prince J. C.
Published: August 2009

Catalytic removal of pollutants in dry combustion gases in a planar stagnation‐point flow over a platinum foil is studied using both numerical and analytical tools. The governing equations have been numerically integrated with the Newton technique, and the response curve has been obtained as functions of temperature and the mixture concentrations. Using the appropriate stoichiometry, the additional oxygen needed to reduce the NO and to achieve complete oxidation of CO has been obtained. The asymptotic analysis leads to an algebraic equation for the surface coverage of empty sites as a function of two nondimensional parameters: the mass transfer number, relating the residence time to the chemical time (sort of Damköhler number), and a parameter, which relates the desorption rate to the adsorption rate of carbon monoxide and depends strongly on temperature. Critical conditions of ignition (light‐off) and extinction are identified and closed form solutions are obtained for these phenomena. © 2009 American Institute of Chemical Engineers AIChE J, 2010
Facial clefting and oroauditory pathway manifestations in ankyloblepharon–ectodermal defects‐cleft lip/palate (AEC) syndrome
Authors: Cole Patrick , Hatef Daniel A. , Kaufman Yoav , Magruder Amy , Bree Alanna , Friedman Ellen , Sindwani Raj , Hollier Larry H.
Published: August 2009

Ankyloblepharon–ectodermal defects‐cleft lip/palate (AEC) Syndrome is a rare disorder characterized by ectodermal dysplasia, along with other malformations such as cleft lip and palate, and various secondary issues such as chronic sinusitis, otitis media, and conductive hearing loss (CHL). The International Research Symposium for AEC Syndrome convened at Baylor College of Medicine in Houston, Texas. Patients with a suspected diagnosis of AEC syndrome attended, and members of the dental, dermatology, plastic surgery, otolaryngology, and audiology services examined each patient. Eighteen patients with a diagnosis of AEC were evaluated. Mean age was 7.5 years (range: 4 months–30 years). Fourteen of the 15 subjects tested (93.33%) demonstrated CHL, with seven showing moderate to severe hearing deficits (41–90 dB). Nine of 13 respondents reported hoareness or voice problems; 8 were noted to display this on examination. Fourteen of 16 subjects reported speech was below average for age; 8 were in speech therapy. All 18 subjects reported a history of otitis externa or otitis media. Eleven of the subjects (61.11%) required myringotomy and pressure equalizing (PE) tubes. All patients demonstrated cleft palate defects. Of these, 16 (94.11%) presented with clefting of the soft palate, and 10 (58.82%) showed hard palate defects. Three subjects (16.67%) were noted to have submucous clefts. Our experience leads us to propose that while the oroauditory problems in those with AEC syndrome is likely multifactorial, many issues may stem from palatal clefting. Despite this, some abnormalities persist following surgical cleft closure, which indicates other complicating factors are also involved. © 2009 Wiley‐Liss, Inc.
Beauvericin Decreases Cell Viability of Wheat
Authors: Šrobárová Antonia , da Silva Jaime A. Teixeira , Kogan Grigorij , Ritieni Alberto , Santini Antonello
Published: August 2009

Recently, beauvericin (BEA) has been recognized as an important toxic compound synthesized by several Fusarium strains, infecting maize, wheat, and rice, worldwide. The effects of BEA on mammalian cells have been studied; however, its effects on the function of host plant cells are largely unknown. The purpose of our work was to assess whether BEA can affect the root and leaf cells of wheat cultivar (cv.) ‘Arina’ seedlings, using a cytotoxicity assay and fluorescence microscopy. Toxigenicity during wheat germination was higher in BEA‐treated wheat seedlings than in non‐treated seedlings (control). Leaf primordial, situated at the base and the tips of treated leaves, were more affected by BEA compared to the control when assayed in medium for cell viability measured by luminescent equipment. BEA‐Treated plant cells secrete adenosine triphosphate (ATP) to the extracellular matrix and invoke more luminescence by luciferase than the non‐treated seedlings. Our results were confirmed by fluorescence microscopy following ‘4′,6‐diamidino‐2‐phenylindole’ (DAPI) staining and by confocal microscopy. In addition, the bioluminescent protein luciferase was observed in the intracellular space indicating presence of ATP. The incidence of nuclear fragmentation increased significantly in cells of seedlings treated with BEA at 40 μM concentration implying that the intracellular phytotoxin BEA plays an important role, possibly as a mediator in cell‐death signalling.
Colomitides A and B: Novel Ketals with an Unusual 2,7‐Dioxabicyclo[3.2.1]octane Ring System from the Aquatic Fungus YMF 1.01029
Authors: Dong Jin‐Yan , Wang Li‐Mei , Song Hong‐Chuang , Shen Kai‐Ze , Zhou Yong‐Ping , Wang Le , Zhang Ke‐Qin
Published: August 2009

Two novel diastereoisomeric bicyclic ketals, colomitides A and B (1 and 2, resp.), together with the known (4RS)‐3,4‐dihydro‐4,8‐dihydroxynaphthalen‐1(2H)‐one (3) and preussomerin E (4), were isolated from liquid cultures of an unidentified freshwater fungus YMF 1.01029. Colomitides possess an unusual 2,7‐dioxabicyclo[3.2.1]octane skeleton. The chemical structures and relative configurations of compounds 1 and 2 were elucidated by spectroscopic means, including 2D‐NMR (HMBC, HMQC, TOCSY, ROESY, and 1H,1H‐COSY). Compounds 1, 2, and 4 showed noticeable antifungal and antibacterial activities.
Immunomodulatory Activity of 3β,6β‐Dihydroxyolean‐12‐en‐27‐oic Acid in Tumor‐Bearing Mice
Authors: Deng Wen , Sun Hong‐Xiang , Chen Feng‐Yang , Yao Min‐Li
Published: August 2009

3β,6β‐Dihydroxyolean‐12‐en‐27‐oic acid (1) is a pentacyclic triterpenoid isolated from the rhizomes of Astilbe chinensis. To evaluate the in vivo antitumor potential and to elucidate its immunological mechanisms, effect of 1 on the growth of mouse‐transplantable tumors, and the immune response in naive and tumor‐bearing mice were investigated. The mice inoculated with mouse tumor cell lines were orally treated with 1 at the doses of 40, 60, and 80 mg/kg for 10 days. The effects of 1 on the growth of mouse‐transplantable S180 sarcoma and H22 hepatoma, splenocyte proliferation, cytotoxic T lymphocyte (CTL) activity, natural killer (NK) cell activity, and production of interleukin‐2 (IL‐2) from splenocytes in S180‐bearing mice were measured. Furthermore, the effect of 1 on 2,4‐dinitrofluorobenzene (DNFB)‐induced delayed‐type hypersensitivity (DTH) reactions and the sheep red blood cell (SRBC)‐induced antibody response in naive mice were also studied. Compound 1 could not only significantly inhibit the growth of mouse transplantable S180 sarcoma and H22 hepatoma, increase splenocytes proliferation, CTL and NK cell activity, and the level of IL‐2 secreted by splenocytes in tumor‐bearing mice, but also remarkably promote the DTH reaction and enhance anti‐SRBC antibody titers in naive mice. These results suggested that 1 could improve both cellular and humoral immune response, and could act as antitumor agent with immunomodulatory activity.
The Effect of an Amino‐Acid Bridge on Binding Affinity and Cleavage Efficiency of Pyrenyl‐Macrocyclic Polyamine Conjugates toward DNA
Authors: Lu Qiao‐Sen , Huang Yu , Li Jing , Zhang Zhong‐Wei , Lin Hong‐Hui , Yu Xiao‐Qi
Published: August 2009

A series of pyrenyl‐macrocyclic polyamines 5a–5c have been prepared and characterized. Their DNA‐cleavage properties were examined under physiological conditions. Without the presence of other additives, the DNA cleavage ability of 5a–5c showed the order of 5c>5a>5b. Absorption and fluorescence experiments showed the binding affinity of 5a–5c to DNA. The interactions of 5a–5c with CT‐DNA indicated that the DNA binding ability followed an order according to their cleavage efficiency. All the results indicated that the structures of amino‐acid bridge in the ligands may affect the DNA binding and cleavage ability. The cleavage‐mechanism studies indicated that singlet oxygen and superoxide free radicals were involved in the catalytic DNA cleavage process.
Antitumor Activity of the Essential Oil from the Leaves of Croton regelianus and Its Component Ascaridole
Authors: Bezerra Daniel P. , Filho José D. B. Marinho , Alves Ana Paula N. N. , Pessoa Cláudia , de Moraes Manoel O. , Pessoa Otília Deusdênia L. , Torres Maria Conceição M. , Silveira Edilberto R. , Viana Francisco A. , Costa‐Lotufo Letícia V.
Published: August 2009

Croton regelianus Muell. Arg., popularly known as ‘velame‐de‐cheiro’, is a native plant from the Northeast of Brazil used in folk medicine to treat diseases of different kinds, including malignant tumors. In this study, the in vitro and in vivo antitumor effects of the essential oil from the leaves of C. regelianus and ascaridole, one of the main constituents, were investigated. In vitro, the essential oil and ascaridole displayed cytotoxicity, showing IC50 values in the range of 22.2 to 48.0 μg/ml in HL‐60 and SF‐295 cell lines for the essential oil, and 6.3 to 18.4 μg/ml in HL‐60 and HCT‐8 cells lines for ascaridole, respectively. The in vivo study, using sarcoma 180 as a tumor model, demonstrated inhibition rates of 28.1 and 31.8% for essential oil, at the 50 and 100 mg/kg, while ascaridole inhibition rates were 33.9% at 10 mg/kg and 33.3% at 20‐mg/kg doses. Histopathological examination showed that the organs were only weakly affected by the treatment. In conclusion, ascaridole has an interesting antitumor activity in sarcoma 180 murine model, probably related to the described cytotoxic activity, and, moreover, its presence in the essential oil from the leaves of C. regelianus could explain, at least in part, the ethnopharmacological use of this plant in the treatment of cancer.
Cardioprotective Effect of ‘Methylamine Irisolidone’, a New Compound, in Hypoxia/Reoxygenation Injury in Cultured Rat Cardiac Myocytes
Authors: Mu Yan‐Ling , Xie Yan‐Ying , Zhou Ling , Zhong Ying , Liu Lu , Bai Hong , Wang Yuan‐Shu , Zhang Xiu‐Mei
Published: August 2009

‘Methylamine irisolidone’ (=5,7‐dihydroxy‐6‐methoxy‐3‐(4‐methoxyphenyl)‐8‐[(methylamino)methyl]‐4H‐[1]benzopyran‐4‐one), a new compound, is a structurally modified kakkalide with good water solubility. In this study, we investigated its effect on hypoxia/reoxygenation (H/R) injury in cultured rat cardiac myocytes. The results showed that methylamine irisolidone could significantly inhibit lactate dehydrogenase (LDH) release, enhance the mitochondrial membrane potential, decrease intracellular calcium (Ca2+) associated with the attenuation of reactive oxygen species (ROS) generation, reduce contents of malondialdehyde (MDA), and increase the activity of superoxide dismutase (SOD) after H/R in a dose‐dependent manner. The present study demonstrated that methylamine irisolidone can directly protect cardiomyocytes against H/R injury, primarily as a result of reduction of the intracellular Ca2+ overload coincident with an attenuation of ROS generation and ROS‐mediated lipid peroxidation, which may contribute to the preservation of mitochondrion function and antioxidant against H/R injury.
An Antifungal Tetrapeptide from the Culture of Penicillium canescens
Authors: Bertinetti Brenda V. , Peña Nora I. , Cabrera Gabriela M.
Published: August 2009

A new tetrapeptide D‐Phe‐L‐Val‐D‐Val‐L‐Tyr (1), along with three known diketopiperazines and pseurotin A, were isolated from the culture of Penicillium canescens, collected from pollen from beehives, in a screening for new antimicrobial products from unexplored sources. The structure of the tetrapeptide, which exhibits antifungal activity comparable with that of the commercial product benomyl against the soybean phytopathogen Fusarium virguliforme, was determined by spectroscopic (2D‐NMR, and MS and MS/MS) and chemical methods, and the sequence was confirmed by comparison with authentic synthetic isomeric peptides.
Cycloartane Triterpenes from Dikamali, the Gum Resin of Gardenia gummifera and Gardenia lucida
Authors: Kunert Olaf , Sreekanth Gandhe , Babu Gummadi Sreedhar , Rao Belvotagi Venkat Rao Adavi , Radhakishan Marupaka , Kumar Bobbala Ravi , Saf Robert , Rao Achanta Venkata Narasimha Appa , Schühly Wolfgang
Published: August 2009

We report on the chemical investigation of dikamali gum, which is the resin of Gardenia gummifera and G. lucida (Rubiaceae). Six new cycloartane triterpenes, dikamaliartanes A–F (1–6, resp.), together with a known flavonoid (7), were isolated and identified by NMR spectroscopy. All six cycloartanes are characterized by an open A‐ring with a free COOH group at C(3). In four of them, the C‐atoms C(23)–C(27) form a 4‐methylfuran‐2‐yl moiety. Bacterial assays using Staphylococcus aureus, Candida albicans, and Mycobacteria have been carried out but did not reveal significant activity.
Partition Coefficient and Molecular Flexibility: The Concept of Lipophilicity Space
Authors: Vistoli Giulio , Pedretti Alessandro , Testa Bernard
Published: August 2009

The rationale of this study was to investigate molecular flexibility and its influence on physicochemical properties with a view to uncovering additional information on the fuzzy concept of dynamic molecular structure. Indeed, it is now known that computed molecular interaction fields (MIFs) such as molecular electrostatic potentials (MEPs) and lipophilicity potentials (MLPs) are conformation‐dependent, as are dipole moments. A database of 125 compounds was used whose conformational space was explored, while conformation‐dependent parameters were computed for each non‐redundant conformer found in the conformational space of the compounds. These parameters were the virtual log P (log PMLP, calculated by a MLP approach), the apolar surface area (ASA), polar surface area (PSA), and solvent‐accessible surface (SAS). For each compound, the range taken by each parameter (its property space) was divided by the number of rotors taken as an index of flexibility, yielding a parameter termed ‘molecular sensitivity’. This parameter was poorly correlated with others (i.e., it contains novel information) and showed the compounds to fall into two broad classes. ‘Sensitive’ molecules are those whose computed property ranges are markedly sensitive to conformational effects, whereas ‘insensitive’ (in fact, less sensitive) molecules have property ranges which are comparatively less affected by conformational fluctuations. A pharmacokinetic application is presented.
Transcatheter pulmonary valve implantation using the edwards SAPIEN™ transcatheter heart valve
Authors: Boone Robert H. , Webb John G. , Horlick Eric , Benson Lee , Cao Qi‐Ling , Nadeem N. , Kiess Marla , Hijazi Ziyad M.
Published: August 2009

Background:

Conduits placed in the right ventricular outflow tract (RVOT) have limited longevity which often requires increasingly complex reoperations. Transcatheter pulmonary valve implantation improves conduit hemodynamics through a minimally invasive approach. We present data for 7 patients treated with the Edwards SAPIEN™ transcatheter heart valve (THV).

Patients:

Patients' ranged in age from 16 to 52 years, one was female, and all had NYHA class II‐III symptoms. Patients had pulmonary homografts that had been placed 2–25 years earlier during the Ross procedure (n = 4), repaired double outlet right ventricle with situs inversus (n = 1), or Rastelli repair for D‐TGA, pulmonary atresia, and ventricular septal defect (n = 2). Patients had either severe pulmonary stenosis and/or moderate to severe pulmonary regurgitation.

Results:

All patients had successful percutaneous implantation of the 23 mm SAPIEN™ THV under general anesthesia. Fluoroscopy times ranged from 16 to 49 mins and procedure times ranged from 110 to 237 mins. The RV:systemic pressure ratio decreased from 78 ± 18 to 39 ± 8%, the RVOT gradient improved from 60.7 ± 24.3 to 14.9 ± 6.9 mm Hg, no patients had pulmonary insufficiency, and all patients had symptom improvement. At a maximum follow‐up of 3.5 years (median 22.5 months), Doppler peak gradients ranged from 7–36 mm Hg, and there is no evidence of late stent fracture or structural valve failure.

Conclusion:

The SAPIEN™ THV can be used successfully in the treatment of patients with right ventricle to pulmonary artery homograft failure. The valve is durable to at least 3.5 years without stent fracture or regurgitation. Clinical trials are underway to assess the long‐term safety and efficacy of this valve. © 2009 Wiley‐Liss, Inc.
Synthesis, Stabilization, Functionalization and, DFT Calculations of Gold Nanoparticles in Fluorous Phases (PTFE and Ionic Liquids)
Authors: Redel Engelbert , Walter Michael , Thomann Ralf , Vollmer Christian , Hussein Laith , Scherer Harald , Krüger Michael , Janiak Christoph
Published: August 2009

Gold nanoparticles (Au‐NPs) were reproducibly obtained by thermal, photolytic, or microwave‐assisted decomposition/reduction under argon from Au(CO)Cl or KAuCl4 in the presence of n‐butylimidazol dispersed in the ionic liquids (ILs) BMIm+BF4−, BMIm+OTf−, or BtMA+NTf2− (BMIm+=n‐butylmethylimidazolium, BtMA+=n‐butyltrimethylammonium, OTf−=−O3SCF3, NTf2−=−N(O2SCF3)2). The ultra small and uniform nanoparticles of about 1–2 nm diameter were produced in BMIm+BF4− and increased in size with the molecular volume of the ionic liquid anion used in BMIm+OTf− and BtMA+NTf2−. Under argon the Au‐NP/IL dispersion is stable without any additional stabilizers or capping molecules. From the ionic liquids, the gold nanoparticles can be functionalized with organic thiol ligands, transferred, and stabilized in different polar and nonpolar organic solvents. Au‐NPs can also be brought onto and stabilized by interaction with a polytetrafluoroethylene (PTFE, Teflon) surface. Density functional theory (DFT) calculations favor interactions between IL anions instead of IL cations. This suggests a Au⋅⋅⋅F interaction and anionic Aun stabilization in fluorine‐containing ILs. The 19F NMR signal in BMIm+BF4− shows a small Au‐NP concentration‐dependent shift. Characterization of the dispersed and deposited gold nanoparticles was done by transmission electron microscopy (TEM/HRTEM), transmission electron diffraction (TED), dynamic light scattering (DLS), UV/Vis absorbance spectroscopy, scanning electron microscopy (SEM), electron spin resonance (ESR), and electron probe micro analyses (EPM, SEM/EDX).
Natural Abundance 25Mg Solid‐State NMR of Mg Oxyanion Systems: A Combined Experimental and Computational Study
Authors: Cahill Lindsay S. , Hanna John V. , Wong Alan , Freitas Jair C. C. , Yates Jonathan R. , Harris Robin K. , Smith Mark E.
Published: August 2009

Solid‐state 25Mg magic angle spinning nuclear magnetic resonance (MAS NMR) data are reported from a range of organic and inorganic magnesium–oxyanion compounds at natural abundance. To constrain the determination of the NMR interaction parameters (δiso, χQ, ηQ) data have been collected at three external magnetic fields (11.7, 14.1 and 18.8 T). Corresponding NMR parameters have also been calculated by using density functional theory (DFT) methods using the GIPAW approach, with good correlations being established between experimental and calculated values of both χQ and δiso. These correlations demonstrate that the 25Mg NMR parameters are very sensitive to the structure, with small changes in the local Mg2+ environment and the overall hydration state profoundly affecting the observed spectra. The observations suggest that 25Mg NMR spectroscopy is a potentially potent probe for addressing some key problems in inorganic materials and of metal centres in biologically relevant molecules.
One‐Step Synthesis of Folic Acid Protected Gold Nanoparticles and Their Receptor‐Mediated Intracellular Uptake
Authors: Li Gaiping , Li Dan , Zhang Lixue , Zhai Junfeng , Wang Erkang
Published: August 2009

We report here a facile method to obtain folic acid (FA)‐protected gold nanoparticles (Au NPs) by heating an aqueous solution of HAuCl4/FA in which FA acts as both the reducing and stabilizing agent. The successful formation of FA‐protected Au NPs is demonstrated by UV/Vis spectroscopy, transmission electron microscopy (TEM), selected‐area electron diffraction (SAED), X‐ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR). The intracellular uptake of these nanoparticles is facilitated by HeLa cells overexpressing the folate reporter, which itself is significantly inhibited by free FA in a competitive assay as quantified by inductively coupled plasma mass spectroscopy (ICP‐MS). This simple one‐step approach affords a new perspective for creating functional nanomaterials, and the resulting biocompatible, functional Au NPs may find some prospective applications in various biomedical fields.
From Mono‐ to Poly‐Substituted Frameworks: A Way of Tuning the Acidic Character of CcH in o‐Carborane Derivatives
Authors: Puga Alberto V. , Teixidor Francesc , Sillanpää Reijo , Kivekäs Raikko , Arca Massimiliano , Barberà Gemma , Viñas Clara
Published: August 2009

The incorporation of iodine atoms onto the boron vertices of the o‐carborane framework causes, according to spectroscopic data, a uniform increase in the acidic character of the CcH (Cc= cluster carbon) vertices, whereas the incorporation of methyl groups onto the boron vertices of the o‐carborane framework reduces their acidity. Methyl groups when attached to boron are electron‐withdrawing in boron clusters, whereas iodine atoms bonded to boron act as electron donors. This has been proven on B‐methyl and B‐iodinated o‐carboranes with NMR spectroscopy measurements and DFT calculations of natural bond orbital (NBO) charges, which show a cumulative buildup of positive cluster‐only total charge (CTC) on B‐methyl o‐carboranes and a cumulative buildup of negative cluster‐only total charge for B‐iodinated o‐carboranes.
Iodinated ortho‐Carboranes as Versatile Building Blocks to Design Intermolecular Interactions in Crystal Lattices
Authors: Puga Alberto V. , Teixidor Francesc , Sillanpää Reijo , Kivekäs Raikko , Viñas Clara
Published: August 2009

The crystal structures of numerous iodinated ortho‐carboranes have been studied, which has revealed the diversity of intermolecular interactions that these substances can adopt in the solid state. The nature—mostly as it relates to hydrogen and/or halogen bonds—and relative strength of such interactions can be adjusted by selectively introducing substituents onto the cluster, thus enabling the rational design of crystal lattices. In this work we present the newly determined crystal structures of the following iodinated ortho‐carboranes: 9‐I‐1,2‐closo‐C2B10H11, 4,5,7,8,9,10,11,12‐I8‐1,2‐closo‐C2B10H4, 3,4,5,6,7,8,9,10,11,12‐I10‐1,2‐closo‐C2B10H2, 1‐Me‐8,9,10,12‐I4‐1,2‐closo‐C2B10H7, 1,2‐Me2‐8,9,10,12‐I4‐1,2‐closo‐C2B10H6, and 1,2‐Ph2‐8,9,10,12‐I4‐1,2‐closo‐C2B10H6. Their 3D supramolecular organization has been thoroughly investigated and compared to similar previously published crystal structures. Such a systematic survey has allowed us to draw some general trends. CcH⋅⋅⋅IB hydrogen bonds (Cc= cluster carbon atoms) appear to be significant in the growth of the crystal lattices of these compounds, given the acidity of hydrogen atoms bonded to Cc, and the polarization of BI bonds. These hydrogen bonds can be disrupted by selectively blocking the positions next to Cc, that is, B(3) and B(6), with bulky substituents that prevent iodine atoms from approaching as hydrogen acceptors. Halogen bonds of the type BI⋅⋅⋅IB are frequently observed in most cases, thus suggesting that these interactions could be attractive in boron clusters. In addition, different substituents can be grafted onto the ortho‐carborane surface, thereby providing further possibilities for homomeric or heteromeric molecular assembly.
Tripeptides of the Type H‐D‐Pro‐Pro‐Xaa‐NH2 as Catalysts for Asymmetric 1,4‐Addition Reactions: Structural Requirements for High Catalytic Efficiency
Authors: Wiesner Markus , Neuburger Markus , Wennemers Helma
Published: August 2009

Analysis of the structural and functional requirements within the asymmetric peptidic catalyst H‐D‐Pro‐Pro‐Asp‐NH2 led to the development of the closely related peptide H‐D‐Pro‐Pro‐Glu‐NH2 as an even more efficient catalyst for asymmetric conjugate addition reactions of aldehydes to nitroolefins. In the presence of as little as 1 mol % of H‐D‐Pro‐Pro‐Glu‐NH2, a broad range of aldehydes and nitroolefins react readily with each other. The resulting γ‐nitroaldehydes were obtained in excellent yields and stereoselectivities at room temperature. Within the structure of the peptidic catalysts, the D‐Pro‐Pro motif is the major contributor to the high stereoselectivities. The C‐terminal amide and the spacer to the carboxylic acid in the side‐chain of the C‐terminal amino acid are responsible for the fine‐tuning of the stereoselectivity. The peptidic catalysts not only allow for highly effective asymmetric catalysis under mild conditions, but also function in the absence of additives.
Asymmetric [2,3]‐Wittig Rearrangement of Oxygenated Allyl Benzyl Ethers in the Presence of a Chiral di‐tBu‐bis(oxazoline) Ligand: A Novel Synthetic Approach to THF Lignans
Authors: Kitamura Maria , Hirokawa Yoshimi , Maezaki Naoyoshi
Published: August 2009

We have accomplished highly enantioselective [2,3]‐Wittig rearrangements of functionalized allyl benzyl ethers in the presence of a chiral di‐tBu‐bis(oxazoline) ligand. In various oxygenated benzylic ethers, the reactions proceeded with excellent diastereo‐ and enantioselectivities, although the presence of a methoxy substituent at the ortho‐position on the benzyl group drastically decreased the enantioselectivity. Conversely, o‐ethyl and o‐phenyl substituents had no significant effect on the selectivity. We found that the C2‐substituent of the allylic moiety played an important role in producing high enantioselectivity. Highly enantioselective [2,3]‐Wittig rearrangement in the presence of catalytic amounts of the chiral ligands is also described.
Enhanced Reactivities of Iron(IV)‐Oxo Porphyrin π‐Cation Radicals in Oxygenation Reactions by Electron‐Donating Axial Ligands
Authors: Kang Yaeun , Chen Hui , Jeong Yu Jin , Lai Wenzhen , Bae Eun Hae , Shaik Sason , Nam Wonwoo
Published: August 2009

The proximal axial ligand in heme iron enzymes plays an important role in tuning the reactivities of iron(IV)‐oxo porphyrin π‐cation radicals in oxidation reactions. The present study reports the effects of axial ligands in olefin epoxidation, aromatic hydroxylation, alcohol oxidation, and alkane hydroxylation, by [(tmp)+. FeIV(O)(p‐Y‐PyO)]+ (1‐Y) (tmp=meso‐tetramesitylporphyrin, p‐Y‐PyO=para‐substituted pyridine N‐oxides, and Y=OCH3, CH3, H, Cl). In all of the oxidation reactions, the reactivities of 1‐Y are found to follow the order 1‐OCH3 > 1‐CH3 > 1‐H > 1‐Cl; negative Hammett ρ values of −1.4 to −2.7 were obtained by plotting the reaction rates against the σp values of the substituents of p‐Y‐PyO. These results, as well as previous ones on the effect of anionic nucleophiles, show that iron(IV)‐oxo porphyrin π‐cation radicals bearing electron‐donating axial ligands are more reactive in oxo‐transfer and hydrogen‐atom abstraction reactions. These results are counterintuitive since iron(IV)‐oxo porphyrin π‐cation radicals are electrophilic species. Theoretical calculations of anionic and neutral ligands reproduced the counterintuitive experimental findings and elucidated the root cause of the axial ligand effects. Thus, in the case of anionic ligands, as the ligand becomes a better electron donor, it strengthens the FeOH bond and thereby enhances its H‐abstraction activity. In addition, it weakens the FeO bond and encourages oxo‐transfer reactivity. Both are Bell–Evans–Polanyi effects, however, in a series of neutral ligands like p‐Y‐PyO, there is a relatively weak trend that appears to originate in two‐state reactivity (TSR). This combination of experiment and theory enabled us to elucidate the factors that control the reactivity patterns of iron(IV)‐oxo porphyrin π‐cation radicals in oxidation reactions and to resolve an enigmatic and fundamental problem.
Epothilone Analogues with Benzimidazole and Quinoline Side Chains: Chemical Synthesis, Antiproliferative Activity, and Interactions with Tubulin
Authors: Dietrich Silvia Anthoine , Lindauer Renate , Stierlin Claire , Gertsch Jürg , Matesanz Ruth , Notararigo Sara , Díaz José Fernando , Altmann Karl‐Heinz
Published: August 2009

A series of epothilone B and D analogues bearing isomeric quinoline or functionalized benzimidazole side chains has been prepared by chemical synthesis in a highly convergent manner. All analogues have been found to interact with the tubulin/microtubule system and to inhibit human cancer cell proliferation in vitro, albeit with different potencies (IC50 values between 1 and 150 nM). The affinity of quinoline‐based epothilone B and D analogues for stabilized microtubules clearly depends on the position of the N‐atom in the quinoline system, while the induction of tubulin polymerization in vitro appears to be less sensitive to N‐positioning. The potent inhibition of human cancer cell growth by epothilone analogues bearing functionalized benzimidazole side chains suggests that these systems might be conjugated with tumor‐targeting moieties to form tumor‐targeted prodrugs.
Synthesis of stoichiometric LiNbO3 nanopowder through a wet chemical method
Authors: Yao Shuhua , Zheng Feifei , Liu Hong , Wang Jiyang , Zhang Huaijin , Yan Tao , Wu Jianbo , Xia Zongren , Qin Xiaoyong
Published: August 2009

Stoichiometric lithium niobate powder which are used as feeding material in near stoichometric LiNbO3 crystal growth have been successfully prepared from commercial niobium hydroxide [Nb(OH)5] and nontoxic DL‐malic acid by a wet chemical method. The synthesis temperature was pre‐determined by the results from thermogravimetric and differential thermal analysis. The structure and morphology of the as‐prepared samples were observed by using the infrared spectroscopy and the scanning electron microscopy. The X‐ray diffraction experiment showed that lithium niobate powder had an ilmenite structure, and its unit cell parameters were calculated to be a = b = 0.5140 nm, c = 1.3738 nm, and V = 0.3144 nm3. The melting point of the synthesized powder is 1239 °C and Curie temperature Tc is 1122 °C. This synthesis method would be helpful to grow the near‐stoichiometric LiNbO3 crystal with double crucible techniques. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Sonochemical synthesis and characterization of ZnO nanorod/Ag nanoparticle composites
Authors: Li Fei , Liu Xueqin , Qin Qinghua , Wu Jianfang , Li Zhen , Huang Xintang
Published: August 2009

A simple sonochemical route for the synthesis of Ag nanoparticles on ZnO nanorods is reported. Ultrasonic irradiation of a mixture of ZnO nanorods, Ag(NH3)2+, and formaldehyde in an aqueous medium yields ZnO nanorod/Ag nanoparticle composites. The powder X‐ray diffraction of the ZnO/Ag composites shows additional diffraction peaks corresponding to the face‐center‐cubic structured Ag crystalline, apart from the signals from the ZnO nanorods. Scanning electron microscopy and transmission electron microscopy images of the ZnO/Ag composites reveal that the ZnO nanorods are coated with Ag nanoparticles with a mean size of several tens nanometer. The absorption band of ZnO/Ag composites is distinctly broadened and red‐shifted, indicating the strong interfacial interaction between ZnO nanorods and Ag nanoparticles. This sonochemical method is simple, mild and readily scaled up, affording a simple way for synthesis of other composites. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Defect structure characteristics in near‐stoichiometric In:LiNbO3 single crystals grown by K2O‐flux method
Authors: Fang Shuangquan , Han Zhaoxiang , Qiao Yingjie , Liu Yingying , Jia Qi
Published: August 2009

With K2O as flux, near‐stoichiometric In:LiNbO3 (In:SLN) crystals with different indium contents were grown by the top seed solution growth (TSSG) method. Defect structure characteristics and the replacement principle of extrinsic ions were derived from X‐ray powder diffraction, differential thermal analysis (DTA), ultraviolet‐visible (UV) absorption and infrared (IR) spectrum measurement. Further analysis indicated that the threshold concentration of In2O3 in near‐stoichiometric LiNbO3 crystals were about 1.1 mol%. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis and field emission properties of SnO2 nanowalls
Authors: Li L. J. , Yu K. , Wang Y.
Published: August 2009

SnO2 nanowalls were synthesized on silicon substrate by the thermal chemical vapor transport method at a low temperature of around 650 °C under atmospheric pressure. The microstructure and morphology of the SnO2 nanowalls were evaluated by using scanning electron microscopies and X‐ray diffraction. Room temperature photoluminescence spectra of the nanowalls showed a broad emission band centering at about 530 nm. Field emission measurements demonstrated that the nanowalls possessed good performance with a turn‐on field of ∼3.5 V/μm and a threshold field of ∼6.1 V/μm. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Columnar grain growth pattern with fluid flowing in molten pool
Authors: Ma Rui , Dong Zhibo , Wei Yanhong , Zhan Xiaohong , Wang Yong
Published: August 2009

A coupled model was used to simulate columnar grain growth in TIG (tungsten inert‐gas) molten pool of nickel base alloy. The cellular automaton algorithm for dendritic growth is incorporated with solute transport model to take fluid flow into consideration. The results indicate that shear flow changes the solute distribution at the S/L (Solid/Liquid) interface, leading to asymmetrical growth of columnar grains. The dendrite arms on the upstream side grow fast, while the growth of dendrite arms on the downstream side is much delayed. However, dendrite arms on both sides are not as well‐developed as the grain growth without flow. With inlet flow velocity increasing, the phenomenon becomes more obvious. In addition, shear flow also results in more severe coring segregation. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis of Ru microspheres by self‐assembly in tungstosilicate acid solution and photocatalytic degradability of cango red
Authors: Zhang Li , Wang Hongyan , Wang Cong
Published: August 2009

The formation of Ru microspheres by hydrothermal treated method in tungstosilicate acid (H4SiW12O40, TSA) solution is described. The particles are characterized by X‐ray diffraction analysis (XRD) and scanning electron microscopy (SEM), respectively. The growth process of these microspheres has been examined. The results show that it is possible to synthesize and assemble other noble metal particles with unique superstructure. The characteristic catalytic behavior of the Ru microspheres is established by studying the decolorization of cango red in the presence of UV light. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An effective IPv4–IPv6 translation mechanism for SIP applications in next generation networks
Authors: Chen Whai‐En , Huang Ya‐Lin , Lin Yi‐Bing
Published: August 2009

In a next generation network, the IPv6‐enabled IP multimedia subsystem (IMS) network may connect to an IPv4 network. When an IPv4/IPv6 dual‐stack user equipment (UE) initiates a call by sending an IPv6 SIP INVITE message to an IPv4‐only user agent (UA), the call cannot be established correctly. To resolve this problem, the IMS‐application layer gateway solution, the redirect solution, and the interactive connectivity establishment solution have been proposed. In this paper, we propose an effective solution where only the IPv6 INVITE message is translated into an IPv4 INVITE message. Upon receipt of the IPv4 200 OK message replied from the IPv4‐only UA, the dual‐stack UE learns that the correspondent UA supports IPv4‐only and utilizes IPv4 instead of IPv6 to send the subsequent SIP messages and real‐time transport protocol (RTP) packets. The proposed solution is compared with the existing solutions in terms of network node modification, call setup complexity, and RTP transmission latency. Our study indicates that the proposed solution outperforms the other three solutions in the call setup and the RTP transmission. Copyright © 2009 John Wiley & Sons, Ltd.
Auditory stream biasing in children with reading impairments
Authors: Ouimet Tialee , Balaban Evan
Published: August 2009

Reading impairments have previously been associated with auditory processing differences. We examinedauditory stream biasing, a global aspect of auditory temporal processing. Children with reading impairments, control children and adults heard a 10 s long stream‐bias‐inducing sound sequence (a repeating 1000 Hz tone) and a test sequence (eight repetitions of two pure tones of 1000 and 1420 Hz in an XYX‐XYX… pattern) with a variable delay interval (from 0.09 to 8 s) between the two sequences. Reading‐impaired children had a significantly lower proportion of streamed responses than control children and adults. Streamed responses in reading‐impaired participants differed according to their musical experience, but musically experienced reading‐impaired participants were still significantly different from musically experienced controls. Reading impairments are associated with global differences in auditory integration, and musical experience needs to be considered when investigating auditory processing capabilities. Copyright © 2009 John Wiley & Sons, Ltd.
High‐sensitivity detection of ATP using bioluminescence at an optical fiber end
Authors: Iinuma Masataka , Ushio Yasuaki , Kuroda Akio , Kadoya Yutaka
Published: August 2009

We investigated the sensitivity of ATP detection based on bioluminescence at an optical fiber end where luciferase molecules were immobilized via silica‐binding protein molecules. Luminescence was detected by an avalanche photodiode (APD), with coupling optics to make full use of the merits of compactness, high quantum efficiency, and low noise of the APD. The core diameter and the numerical aperture of the optical fiber, as well as the design of the coupling optics, were optimized so as to realize high photon‐collection efficiency. A detection limit of about 10−10 M was obtained, which corresponds to 10−15 mol of ATP. A rough estimation shows that the photon count rate is still two orders of magnitude lower than that limited by diffusion or reaction processes, implying a possibility of further improvement of the sensitivity. © 2009 Wiley Periodicals, Inc. Electron Comm Jpn, 92(9): 53–59, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10054
Mechanical dissociation of retinal neurons with vibration
Authors: Motomura Tamami , Hayashida Yuki , Murayama Nobuki
Published: August 2009

Neuromorphic devices that implement the functions of biological neural circuits by means of VLSI technology have been attracting great attention in engineering fields in the last decade. Concurrently, progress in neuroscience research has demonstrated nonlinear computations at the single neuron level, suggesting that individual neurons are not merely passive circuit elements but computational units. Thus, elucidating the properties of neuronal signal processing is an essential step in developing the next generation of neuromorphic devices. In this study, we developed a method of dissociating single neurons from specific sublayers of mammalian retinas without using proteolytic enzymes, instead combining tissue incubation in a low‐Ca2+ medium with a vibrodissociation technique previously developed for slices of brain and spinal cord. Our method takes less time and requires less manual skill than in the conventional enzymatic method, but yields a sufficient number of cells usable for acute electrophysiological experiments. Single retinal neurons dissociated by our method are useful for measuring nonlinear membrane conductances as well as spike firing properties in the perforated‐patch whole‐cell configuration. These neurons also enable us to investigate the effects of proteolytic enzymes on membrane excitability in such cells. © 2009 Wiley Periodicals, Inc. Electron Comm Jpn, 92(9): 43–52, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10062
Fabrication and evaluation of complementary logic circuits using zinc oxide and pentacene thin film transistor
Authors: Iechi Hiroyuki , Watanabe Yasuyuki , Yamauchi Hiroshi , Kudo Kazuhiro
Published: August 2009

We fabricated hybrid complementary inverters with n‐channel zinc oxide (ZnO) transistors as the n‐type inorganic material and p‐channel organic transistors using pentacene as the p‐type organic material. The complementary inverter exhibited a large voltage gain of 10 to 12 and a cutoff frequency of 0.5 kHz. ZnO thin film transistors show n‐type semiconducting properties having field‐effect mobility of 2.1×10−3 cm2/Vs. On the other hand, pentacene thin film transistors show p‐type semiconducting properties having field‐effect mobility of 3.2×10−2 cm2/Vs. We describe basic charge transfer characteristics of ZnO thin films. The results obtained here demonstrate that it is important for the transistor using ZnO to be injected charge from electrode to semiconducting material effectively. © 2009 Wiley Periodicals, Inc. Electron Comm Jpn, 92(9): 36–42, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10085
An electrochemical sensor array and its application to real‐time brain slice imaging
Authors: Kasai Nahoko , Shimada Akiyoshi , Nyberg Tobias , Torimitsu Keiichi
Published: August 2009

An electrochemical sensing system using a planar microelectrode array has been developed for monitoring biological molecules with relatively high spatial and temporal resolution. This allows noninvasive real‐time imaging of biological molecules released from tissue. In this study, we establish a multichannel hydrogen peroxide (H2O2) sensing system to monitor the real‐time H2O2 distribution in tissue using a planar sensor array. H2O2 is known to be associated with the pathology of neurological diseases because it is a by‐product of degenerative reactions involving reactive oxygen species, which are a major cause of oxidative stress in mammalian cells. The sensor array is based on a 64‐channel ITO electrode array composed of 50 × 50 μm electrodes modified with an enzyme (horseradish peroxidase) and an electron transfer mediator. We place a cultured rat hippocampal slice on the array and measure the current at each sensor using a multipotentiostat. When we introduce bicuculline into the solution as a stimulant in the presence of a catalase inhibitor, we can observe a distinct increase in the H2O2 concentration. This real‐time H2O2 distribution monitoring system is a powerful tool with which to explore the neuronal cell death mechanism in biological systems. © 2009 Wiley Periodicals, Inc. Electron Comm Jpn, 92(9): 1–6, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10140