bluuebunny/crossref_metadata_2025 huggingface dataset:
An intelligent MPEG rate control in 2.4 GHz frequency
Authors: Kazemian H. B. , Chantaraskul S.
Published: May 2009

Transmitting Moving Picture Expert Group (MPEG) Variable Bit Rate (VBR) video stream over 2.4 GHz wireless frequency demands a large bandwidth and may result in data loss and delay, because of excessive fluctuation in bit rate. Transmission over 2.4 GHz frequency further causes uncertainty due to interferences by other wireless devices in the same frequency band and/or common dynamic channel noises. As a result, an intelligent system has been developed for MPEG video transmission over 2.4 GHz frequency band. A novel fuzzy controller automatically determines the quantization scale for each Group Of Picture (GOP) of the encoder during the transmission period. Moreover, a fuzzy controller and a neural‐fuzzy controller stream the MPEG video data to conform to the current condition of dynamic wireless channel to maintain image quality during the transmission. In the intelligent system, rather than choosing the parameters associated with a given membership function arbitrarily, these parameters are chosen as such to tailor the membership functions to the desired input/output data. The intelligent system computes and trains the system in such a way that its output will be equal to the desired value. Computer simulation results demonstrate that the proposed intelligent technique increases transmission rate and reduces data loss, excessive delay and image quality degradation as compared with a conventional video transmission over 2.4 GHz frequency band. Copyright © 2009 John Wiley & Sons, Ltd.
Algorithmic stemmers or morphological analysis? An evaluation
Authors: Fautsch Claire , Savoy Jacques
Published: May 2009

It is important in information retrieval (IR), information extraction, or classification tasks that morphologically related forms are conflated under the same stem (using stemmer) or lemma (using morphological analyzer). To achieve this for the English language, algorithmic stemming or various morphological analysis approaches have been suggested. Based on Cross‐Language Evaluation Forum test collections containing 284 queries and various IR models, this article evaluates these word‐normalization proposals. Stemming improves the mean average precision significantly by around 7% while performance differences are not significant when comparing various algorithmic stemmers or algorithmic stemmers and morphological analysis. Accounting for thesaurus class numbers during indexing does not modify overall retrieval performances. Finally, we demonstrate that including a stop word list, even one containing only around 10 terms, might significantly improve retrieval performance, depending on the IR model.
Nuclearity Control in Molecular Iron Phosphates through Choice of Iron Precursors and Ancillary Ligands
Authors: Murugavel Ramaswamy , Gogoi Nayanmoni , Suresh K. G. , Layek S. , Verma H. C.
Published: May 2009

One to five, one at a time: The choice of iron precursors and the amine co‐ligand are employed as switches to control the nuclearity in iron phosphate molecular clusters. Using this control, it is possible to isolate selectively either a mono, di, tri, tetra, or pentanuclear cluster, for a given set of reactants.

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The potential of a mono‐organophosphate ester in assembling low to medium nuclearity iron complexes with novel topological architectures has been investigated. Reaction of 2,6‐diisopropylphenyl dihydrogen phosphate (dipp‐H2) with ferrous acetate under an inert atmosphere resulted in the formation of mononuclear, [FeII(dipp‐H)2(py)4] (1) (py=pyridine), dinuclear [FeIII2O(dipp‐H)4(3,5‐dmpz)3(thf)]⋅(3,5‐dmpz)⋅(thf)3 (2) (3,5‐dmpz=3,5‐dimethylpyrazole, thf=tetrahydrofuran), and trinuclear [FeIII2FeIIO(dipp‐H)6(thf)3]⋅(collidine) (3) complexes by changing the ancillary amine used in the reaction. Use of a preformed μ3‐oxo bridged trinuclear complex, [FeIII3O(O2CR)6(H2O)3]X (X=Cl and NO3), as the precursor yielded two tetranuclear iron phosphates, [FeIII4O(dipp)3(py)4(PhCOO)4]⋅(toluene)3 (4) and [FeIII4O(dipp)3(OAc)4(py)4]⋅(py)2 (5), having a core structure similar to those found in tetranuclear iron phosphonates. When FeCl3⋅6H2O was used as the iron precursor, an unprecedented pentanuclear iron phosphate complex, [FeIII5O(dipp)6(py)4Cl2][pyH] (6) with a novel structure was isolated. Another pentanuclear complex having a similar core structure, [Fe5O(dipp)6(HO2CPh)3(CH3CN)3Cl] (7) was isolated on treatment of dipp‐H2 with the triangular complex, [FeIII3O(O2CPh)6(H2O)3]Cl in the absence of any added amine co‐ligand. Compounds 1–7 have been characterized by analytical techniques, spectroscopic studies, single crystal X‐ray diffraction studies, and magnetic measurements. The Mössbauer studies carried out at room temperature support the formulation of all the compounds.
Roles and regulation of Thy‐1, a context‐dependent modulator of cell phenotype
Authors: Bradley John E. , Ramirez Gustavo , Hagood James S.
Published: May 2009

Thy‐1 or CD90 is a glycophosphatidylinositol‐linked glycoprotein expressed on the surface of neurons, thymocytes, subsets of fibroblasts, endothelial cells, mesangial cells and some hematopoietic cells. Thy‐1 is evolutionarily conserved, developmentally regulated, and often has dramatic effects on cell phenotype; however, the effects vary between and in some cases within cell types and tissues, and between similar tissues in different species, indicating that the biological role of Thy‐1 is context‐dependent. Thy‐1 exists in soluble form in some body fluids; however, the mechanisms of its shedding are unknown. In addition, Thy‐1 expression can be regulated by epigenetic silencing. Because Thy‐1 modulates many basic cellular processes and is involved in the pathogenesis of a number of diseases, it is important to better understand its regulation. © 2009 International Union of Biochemistry and Molecular Biology, Inc.
Computer software for reducing the learning time of marine engineers
Authors: Orosa José A.
Published: May 2009

Nowadays, in convergence of European university studies, the syllabus of the Marine Engineer University studies in Spain employs considerable time to study Applied Thermodynamics. Engineering Equation Solver (EES) was chosen as the best answer. In order to validate this solution, a case study was performed. © 2009 Wiley Periodicals, Inc. Comput Appl Eng Educ 19: 647–650, 2011
The VSDS environment based laboratory in computer architecture and organisation
Authors: Grbanovic Nenad , Nikolic Bosko , Djordjevic Jovan
Published: May 2009

Courses in computer architecture and organisation are indispensable part of any computer engineering curriculum. In most of cases these courses include the work in the laboratory with the aim to provide students not only with the theoretical background but also with some practical experience. The article presents an approach of achieving this using the originally developed VSDS environment. The background and motivation leading towards the development of the VSDS environment are first given. Then, the VSDS environment features are briefly described. Finally, the use of the VSDS environment in laboratories for the courses in the logical design of digital systems, the computer architecture and organisation and the design of computer systems is presented. © 2009 Wiley Periodicals, Inc. Comput Appl Eng Educ 19: 685–696, 2011
Internet‐based instructional resource exposing middle school students to structural and earthquake engineering
Authors: Mosqueda Gilberto , Ahmadizadeh Mehdi , Tangalos Sofia , Moore‐Russo Deborah
Published: May 2009

An all‐inclusive web resource has been developed that links the study of earthquakes and engineering design to middle grades' (students of ages 10–15) science, mathematics, and technology. It was created to help students understand how earthquakes affect humans and how engineered solutions can mitigate damage. One key component of the website is an innovative internet‐based structural simulation program that allows students to design and simulate the behavior of a building model under earthquake loads. The simulation component is coupled with a hands‐on activity, where students build the model they have designed using wood dowels and pegboards. The students can then use a small shake table to physically simulate and experimentally verify the performance of their models under the design earthquakes. The simulation component has been calibrated to physical models using materials recommended for construction. The website also includes detailed information on earthquake engineering design, lesson plans for implementation in classrooms, a searchable database providing links to authoritative resources on earthquakes and other natural disasters, and national education standards for STEM subject topics. © 2009 Wiley Periodicals, Inc. Comput Appl Eng Educ 19: 724–732, 2011
Using learning style‐based diagnosis tool to enhance collaborative learning in an undergraduate engineering curriculum
Authors: Huang Chenn‐Jung , Liao Jia‐Jian , Shen Hung‐Yen , Aye Nwe Ni , Wang Yu‐Wu , Chen Hong‐Xin , Yang Dian‐Xiu , Luo Yun‐Cheng , Chuang Yi‐Ta
Published: May 2009

In this study, an intelligent learning style aware diagnosis agent for computer‐supported cooperative learning is proposed. Learners are first assigned to heterogeneous groups based on their learning styles questionnaire given right before the beginning of learning activities on the e‐learning platform. The proposed diagnosis agent then scrutinizes each learner's learning portfolio on e‐learning platform and automatically issues feedback messages in case some learner's behavior that is unfitted to his/her learning styles or devious argument on discussion board or wiki is detected. The Moodle, an open‐source software e‐learning platform, is used to establish the cooperative learning environment for this study. The experimental results reveal that the proposed learning style aware diagnosis agent indeed boosts the performance of the learners. © 2009 Wiley Periodicals, Inc. Comput Appl Eng Educ 19: 739–746, 2011
Education set design for smart home applications
Authors: Yilmaz Ercan Nurcan
Published: May 2009

Along with the increasing number of smart home applications, the need for the education of those systems has been unavoidable. Smart homes are a building and occupy large area. It has a lot of special control systems, communication systems and wiring. Thus, education of smart home systems requires special laboratories. At the places where special laboratories do not exist, the education is carried on theoretically. This is a problem. To achieve good smart home education a close collaboration between practice and theory is required. In this study, it has been tried to make an approach to the problem. So, the education set has been developed for better education than only theoretical education. © 2009 Wiley Periodicals, Inc. Comput Appl Eng Educ 19: 631–638, 2011
The Engineering of Bacteria Bearing Azido‐Pseudaminic Acid‐Modified Flagella
Authors: Liu Feng , Aubry Annie J. , Schoenhofen Ian C. , Logan Susan M. , Tanner Martin E.
Published: May 2009

Catch a tiger by the tail: We have demonstrated that by feeding nonmotile mutant C. jejuni bacteria with a neutral azide‐labelled pseudaminic acid precursor we can restore their ability to generate functional flagella. The presence of azido‐pseudaminic acid on the surface of the flagella provides a bio‐orthogonal chemical handle that can be used to modify the flagellar proteins.

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Engineered Two‐Helix Small Proteins for Molecular Recognition
Authors: Webster Jack M. , Zhang Rong , Gambhir Sanjiv S. , Cheng Zhen , Syud Faisal A.
Published: May 2009

Less is more: By starting with a high‐affinity HER2‐binding 3‐helix affibody molecule, we successfully developed 2‐helix small protein binders with 5 nM affinities by using a combination of several different strategies. Our efforts clearly suggest that 2‐helix small proteins against important tumor targets can be obtained by rational protein design and engineering.

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Site‐specific Protein Cross‐Linking with Genetically Incorporated 3,4‐Dihydroxy‐L‐Phenylalanine
Authors: Umeda Aiko , Thibodeaux Gabrielle Nina , Zhu Jie , Lee YungAh , Zhang Zhiwen Jonathan
Published: May 2009

Come together right now with L‐DOPA: Chemical cross‐linking is widely used to study protein–protein interactions. However, many cross‐linking agents suffer from low reactivity or selectivity. An efficient and selective reaction of site‐specific protein cross‐linking was achieved using genetically incorporated 3,4‐dihydroxy‐L‐phenylalanine.

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[18F]SiFA‐isothiocyanate: A New Highly Effective Radioactive Labeling Agent for Lysine‐Containing Proteins
Authors: Rosa‐Neto Pedro , Wängler Björn , Iovkova Ljuba , Boening Guido , Reader Andrew , Jurkschat Klaus , Schirrmacher Esther
Published: May 2009

A highly efficient 18F‐labeling synthon for universal protein labeling is reported. Diverse 18F‐labeled proteins of 66–144 kDa were prepared with [18F]SiFA‐isothiocyanate synthesized by an isotopic 19F for 18F exchange at the silicon atom. Overall preparative radiochemical yields were 20–40 % after 40–50 min. No bone uptake of 18F radioactivity was detected until 90 min post‐injection of 18F‐SiFA‐RSA; this demonstrates the metabolic stability of the [18F]SiFA moiety.

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Two Base Pair Duplexes Suffice to Build a Novel Material
Authors: Meng Martin , Ahlborn Carolin , Bauer Matthias , Plietzsch Oliver , Soomro Shahid A. , Singh Arunoday , Muller Thierry , Wenzel Wolfgang , Bräse Stefan , Richert Clemens
Published: May 2009

Tetrahedral DNA hybrids with tetrakis(p‐hydroxyphenyl)methane cores hybridize in a sequence‐specific fashion at much higher temperatures than isolated linear duplexes. Dinucleotide DNA arms suffice to induce the formation of a solid at room temperature; this demonstrates the strength of multivalent binding. The graphic shows a view of a modeled assembly.

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Spontaneous coronary artery dissection: A Western Denmark Heart Registry Study
Authors: Mortensen K.H. , Thuesen L. , Kristensen I.B. , Christiansen E.H.
Published: May 2009

Background: Spontaneous coronary artery dissection (SCAD) is a rare cause of acute coronary syndrome (ACS) that associates with a high acute‐phase mortality rate, whereas long‐term outcome is less well described. Objective: To describe the incidence, predictors, and prognosis of SCAD. Design: Retrospective case‐identification study from the Western Denmark Heart Registry and the database of the Forensic Institute at Aarhus University from 1999 through 2007. Results: SCAD was documented in 22 of 32,869 (0.7‰) angiograms in the angiographic registry. The SCAD incidence among cases of ACS was 22 of 11,175 (2.0‰). None was seen in the forensic database. The mean age was 48.7 ± 8.9 years (range: 37–71 years). Females constituted 17 of 22 (77%) patients and all had undergone one or more pregnancies; two cases occurred in the postpartum period. The left descending artery (LAD) was the predominant site of entry. The age distribution, prevalence of the cardiovascular risk factors, presence of coronary atherosclerosis, and entry of the dissection were comparable among genders. Treatment was percutaneous coronary intervention in 13 of 22 (59%), coronary artery bypass operation in 2 of 22 (9%), and medical treatment in 7 of 22 (32%) patients. The mean follow‐up period was 3.6 ± 2.9 years. One patient suffered from recurrent SCAD; another patient died suddenly. The MACE‐ (cardiac death, nonfatal myocardial infarction, and new revascularization) free survival was 81% after 24 months. Conclusion: SCAD is a rare disease that mainly affects younger women. Compared with earlier reports, the prognosis seems to be improved by early diagnosis and interventional treatment. © 2009 Wiley‐Liss, Inc.
Exact deployment of stents in ostial renal artery stenosis using the stent tail wire or Szabo technique
Authors: Salazar Miguel , Kern Morton J. , Patel Pranav M.
Published: May 2009

This report describes a technique for the exact deployment of a stent in ostial renal artery stenosis (RAS) by using a second wire inserted through the last cell of a stent. This stent tail wire or anchor technique was first described by Szabo et al. (Am J Cardiol 2005; 96:212H) and facilitates precise aorto‐ostial stent deployment in cases of atherosclerotic RAS. The technique also helps to eliminate errors of improper stent positioning at this aorto‐renal junction, and may possibly minimize patient exposure to ionizing radiation and contrast dye. © 2009 Wiley‐Liss, Inc.
Comparison of magnetically navigated and conventional wire percutaneous coronary intervention of a single discrete stenosis
Authors: Patterson Mark S. , van Nooijen Ferdinand , Ijsselmuiden Alexander , Dirksen Maurits , Domburg Ron Van , Serruys Patrick , Kiemeneij Ferdinand
Published: May 2009

Objective:

The objective of this study is to compare magnetic guidewire navigation in percutaneous coronary intervention (MPCI) to conventional percutaneous coronary intervention (CPCI) for the elective treatment of a single discrete stenosis.

Background:

Magnetic navigation actively steers an angioplasty wire‐tip and may improve PCI procedures, but it is not known whether the intricacy and increased preparation necessary for using the system negatively influences the performance of simple procedures in terms of time and contrast use.

Methods:

The procedures of 44 patients (mean age 65 ± 10 year) undergoing elective single vessel MPCI of a single discrete stenosis were matched for age, gender, and lesion location with 44 concurrent patients (mean age 65 ± 10 year) undergoing CPCI. The major endpoint was procedural time.

Results:

Technical success was defined as an intraluminal wire position distal to the stenosis. Procedural outcome, contrast use, and costs were evaluated. Clinical demographics and angiographic characteristics of the two groups were similar, except for a higher incidence of previous MI and class III angina pectoris in the conventional group. The technical success rate was high and identical in both groups (97.7%). Procedural and fluoroscopy times were not significantly different for MPCI compared to CPCI (21.0 ± 14.5 min vs. 24.7 ± 14.0 min; 4.9 ± 4.8 min vs. 7.3 ± 10.3 min, P = NS). There was a significant reduction in median contrast use [60 ml/patient (41–100) vs. 100 ml/patient (64–130); P = 0.006].

Conclusion:

Magnetic navigation does not increase procedural time, irradiation, equipment use, or cost compared to conventional PCI of a single discrete stenosis. It proved feasible, yielding high rates of procedural success with less contrast use. © 2009 Wiley‐Liss, Inc.
Experimental Investigation and Modeling Approach of the Phenylacetonitrile Alkylation Process in a Microreactor
Authors: Borovinskaya E. S. , Mammitzsch L. , Uvarov V. M. , Schael F. , Reschetilowski W.
Published: May 2009

The application of microreaction technology has the potential to intensify chemical processes. It is therefore of great interest to investigate the operating efficiency of a multiphase process such as the alkylation of phenylacetonitrile in a microreactor and to compare the performance to a batch reactor. The undeniable advantages of continuous microreactor systems for this process were demonstrated. Furthermore, the influence of the organic to aqueous phase ratio in the microreactor was investigated. A model of the reaction course was formulated based on experimental data. This model was used in the analysis and modeling of the alkylation process in a microreactor and found to be adequate. The optimal microreactor performance conditions were determined using the numerical optimization technique (Harrington's desirability function) and confirmed by experiments.
Guanosine Hydrogen‐Bonded Scaffolds: A New Way to Control the Bottom‐Up Realisation of Well‐Defined Nanoarchitectures
Authors: Lena Stefano , Masiero Stefano , Pieraccini Silvia , Spada Gian Piero
Published: May 2009

Over the last two decades, guanosine‐related molecules have been of interest in different areas, ranging from structural biology to medicinal chemistry, supramolecular chemistry and nanotechnology. The guanine base is a multiple hydrogen‐bonding unit, capable also of binding to cations, and fits very well with contemporary studies in supramolecular chemistry, self‐assembly and non‐covalent synthesis. This Concepts article, after reviewing on the diversification of self‐organised assemblies from guanosine‐based low‐molecular‐weight molecules, will mainly focus on the use of guanine moiety as a potential scaffold for designing functional materials of tailored physical properties.
High‐Performance p‐Channel Organic Semiconducting Candidates Based on Benzo[1,2‐k;4,5‐k′]difluoranthene Derivatives
Authors: Liu Wei‐Szu , Liu Chia‐Chun , Kuo Ming‐Yu
Published: May 2009

Orbital promises: Frontier orbital analyses showed that the small λ+ value of 8,17‐di‐n‐hexylbenzo[1,2‐k;4,5‐k′]difluoranthene (DH‐BDF) is owed to the nonbonding character of the BDF framework. The calculated adiabatic ionic potential and hole mobility indicates that this compound is a p‐type air‐stable organic field‐effect transistor, which promises to be a soluble, stable and high‐performance p‐type organic semiconductor.

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Osmabenzenes from Osmacycles Containing an η2‐Coordinated Olefin
Authors: Gong Lei , Chen Zhening , Lin Yumei , He Xumin , Wen Ting Bin , Xu Xin , Xia Haiping
Published: May 2009

Osmabenzenes can be easily synthesized from two η2‐coordinated olefin osmacycles in the presence of benzonitrile by means of facile hydrogen‐transfer conversions (see graphic). Mechanisms for the formation of osmabenzenes are proposed based on DFT calculations.

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Treatment of HCCC(CH3)(OH)CHCH2 with [OsCl2(PPh3)3] in dichloromethane yielded the η2‐olefin‐coordinated osmacycle [Os{CHC(PPh3)C(CH2)‐η2‐CHCH2}Cl2(PPh3)2] (9). Transformations of osmacycle 9 by treatment with benzonitrile under various conditions have been investigated. Reaction of 9 with excess benzonitrile at room temperature afforded the dicationic osmacycle [Os{CHC(PPh3)C(CH2)‐η2‐CHCH2}(PhCN)2(PPh3)2]Cl2 (11) by ligand substitution, which reacted further to the intramolecularly coordinated η2‐allene complex [Os{CHC(PPh3)C(CH3)(η2‐CCH2)}(PhCN)2(PPh3)2]Cl2 (12). In contrast, heating a chloroform solution of 9 to the reflux temperature in the presence of excess benzonitrile generated osmabenzene [Os{CHC(PPh3)C(CH3)CHCH}(PhCN)2(PPh3)2]Cl2 (14). Complexes 11, 12 and 14 are in fact isomers. In the absence of excess benzonitrile, the isolated dicationic 12 and 14 readily dissociate the benzonitrile ligands in solution to produce the neutral complex [Os{CHC(PPh3)C(CH3)(η2‐CCH2)}Cl2(PPh3)2] (13) and the monocationic osmabenzene [Os{CHC(PPh3)C(CH3)CHCH}Cl(PhCN)(PPh3)2]BPh4 (15), respectively. Mechanisms for the formation of osmabenzene 14 from 11 and 12 are proposed based on DFT calculations.
Complexation of Aliphatic Ammonium Ions with a Water‐Soluble Cucurbit[6]uril Derivative in Pure Water: Isothermal Calorimetric, NMR, and X‐ray Crystallographic Study
Authors: Kim Youngkook , Kim Hyunuk , Ko Young Ho , Selvapalam Narayanan , Rekharsky Mikhail V. , Inoue Yoshihisa , Kim Kimoon
Published: May 2009

Without interference: The complexation of aliphatic ammonium ions with a water‐soluble cucurbit[6]uril (CB[6]) derivative, CB*[6] (see picture), in pure water is investigated by isothermal titration calorimetry, NMR spectroscopy, and X‐ray crystallography. The binding affinity of the host in pure water is 2–5 orders of magnitude higher than that in the presence of interfering ions, such as protons and alkali metal ions.

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Complexation of a water‐soluble cucurbituril (CB) derivative, cyclohexanocucurbit[6]uril (CB*[6]), the cavity dimensions of which are essentially the same as those of CB[6], with various organic mono‐ and diammonium ions has been studied by isothermal titration calorimetry and 1H NMR spectroscopy. The binding affinity of CB*[6] with the guest molecules in water is 3–5 and 2–3 orders of magnitude higher than those of CB[6] in 50 % formic acid and in 0.05 m NaCl solution, respectively, which is mainly due to the larger enthalpic gains upon complex formation in the absence of interfering ions, such as protons and Na+. In particular, the binding constant (K) of spermine to CB*[6] was measured to be 3.4×1012 m−1, which is the highest binding constant ever reported for CB[6] or its derivatives. We also obtained the X‐ray crystal structures of α,ω‐alkanediammonium ions (CnDA2+, n=4–8) and spermine complexes with CB[6], in which the aliphatic chains of the guest molecules take an extended or partially bent conformation inside the CB[6] cavity, depending on the chain length. The hexamethylene chain of C6DA2+ takes a twisted conformation, which not only allows strong ion–dipole interactions between the ammonium groups and the carbonyl groups at the portals, but also increases hydrophobic interactions between the alkyl part of the guest and the inner wall of the host, which results in the largest enthalpic gain among α,ω‐alkanediammonium ions. The thermodynamic parameters associated with the complexation are discussed in relation to the binding modes and conformations of the aliphatic chain of the guest molecules inside the host, which were investigated by 1H NMR spectroscopy and X‐ray crystallography.
Highly Enantioselective One‐Pot, Three‐Component Mannich‐type Reaction Catalyzed by an N,N′‐Dioxide–Scandium(III) Complex
Authors: Chen Shikui , Hou Zongrui , Zhu Yin , Wang Jing , Lin Lili , Liu Xiaohua , Feng Xiaoming
Published: May 2009

Mild‐mannered Mannich reaction: Highly enantioselective one‐pot, three‐component Mannich‐type reaction of aldehydes, 2‐aminophenol, and ketene silyl acetal with 5 mol % of a C2‐symmetric N,N′‐dioxide‐based scandium(III) triflate (2:1) complex as the catalyst was achieved under mild conditions (see scheme), which facilitated the asymmetric synthesis of biologically interesting β‐amino esters.

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How are Heteroelements (Ga and Ge) Incorporated in Silicate Oligomers?
Authors: Schaack Bernd Bastian , Schrader Wolfgang , Schüth Ferdi
Published: May 2009

Uncovering the mystery: Typical zeolite prenucleating solutions containing Ga and Ge were studied by ESI‐MS. Ga and Ge incorporate into the oligomers in different ways, and their structure‐directing effect appears stronger than that of the template. MS/MS experiments were used to obtain detailed structural information about the occurring species (see figure).

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The properties of microporous solids can be strongly influenced during the first stages of solid‐state formation from solution. Furthermore, their properties are directly related to the presence, number, and character of intra‐ or extraframework heteroelements. In this contribution we studied the influence of the substitution of silicon against heteroelements, such as gallium and germanium. The aqueous prenucleating solutions were obtained by hydrolysis of the silicon and heteroelement sources in the presence of tetraalkylammonium cations. The time‐resolved stepwise formation of larger oligomers was studied by using electrospray ionization mass spectrometry (ESI‐MS). Furthermore, the structures of the obtained signals were verified by using MS/MS experiments, which led to the conclusion that strong structure‐directing effects emerge from the introduction of heteroelements into the solutions.
Untersuchung der Ultrafeinmahlung von Bariumsulfat
Authors: Petrova A. , Tomas J.
Published: May 2009

Die Ultrafeinmahlung von Bariumsulfat wurde in einer Ringspaltmühle untersucht und dazu diskontinuierliche Versuche durchgeführt. Es zeigt sich, dass die eingetragene Energie, der Mahlkörperfüllungsgrad sowie die Mahlgutkonzentration einen signifikanten Einfluss auf das Zerkleinerungsergebnis haben. Die Agglomeration der Partikel wurde mit einem handelsüblichen Dispergiermittel verhindert, das einen signifikanten Einfluss auf den spezifischen Leistungseintrag und die Energieausnutzung in der Mühle nimmt.
Pd/C/PPh3: A Simple and Efficient Catalyst System for Double Carbonylation Reactions
Authors: LIU Jianming , ZHENG Shuzhan , SUN Wei , XIA Chungu
Published: May 2009

The double carbonylation of iodobenzene and diethylamine proceeds smoothly in the presence of Pd/C and carbon monoxide to afford the corresponding α‐keto amide in good yields with excellent selectivity. In addition, other aryl iodides and secondary amines also react under similar conditions to form α‐keto amides in good yields.
Reactivity of Carboxyl‐functionalized Cubane‐like Photocyclodimer of 2‐Substituted Naphthalene toward Aromatic Amines
Authors: LIAO Guihong , LUO Lin , WU Xiaoling , LEI Lei , TUNG Chenho , WU Lizhu
Published: May 2009

Reactions of carboxyl‐functionalized cubane‐like photocyclodimer 2 with a series of aromatic amines 3 were investigated for understanding the reactivity of this unique system. Spectroscopic and X‐ray crystal structural analyses demonstrate that N,N′‐dicyclohexylcarbodiimide (DCC) is reactive toward 2 affording stable 4 with a well‐retained cubane‐like structure. With the assistance of DCC, mono‐ and diacyl‐substituted photocyclodimers of 2‐sustituted naphthalene (5 and 6) have also been achieved in reasonable yields in addition to the formation of 4. Subtle change in the electronic properties of the series of aromatic amines 3 modulates the reactivity and product distribution remarkably.
Dynamical Complexity in Electrochemical Oxidations of Thiocyanate
Authors: LIU Li , FENG Jiamin , WU Guoguang , LÜ Xiaoli , Gao Qingyu
Published: May 2009

Kinetics and mechanism of the electrochemical oxidation of thiocyanate on a Pt electrode were investigated by using various electrochemical methods, in which both current and potential oscillations have been observed. Cyclic voltammetry measurements illustrate that the oxidation process consists of two steps. In addition to the oscillatory behavior, the system also exhibits bistability, in which the oxidation could be switched between a high and a low current density states with a temporal potential perturbation. The presence of inert ions with stronger absorption also induces transitions from oscillatory to steady reactions in the thiocyanate system.
Sm1.5Sr0.5MO4 (M=Ni, Co, Fe) Cathode Catalysts for Ammonia Synthesis at Atmospheric Pressure and Low Temperature
Authors: XU Gaochao , LIU Ruiquan
Published: May 2009

Sm1.5Sr0.5MO4 (M=Ni, Co, Fe) (SSM) catalysts were prepared by a sol‐gel method and characterized by X‐ray diffraction (XRD) and scanning electron microscopy (SEM). Ammonia was synthesized from wet hydrogen and dry nitrogen at atmospheric pressure and low temperature (25–100 °C) with applied voltage, using SSM as a cathode, Ni‐Ce0.8Sm0.2O2−δ (Ni‐SDC) as an anode, and silver‐platinum film as a current collector, Nafion proton exchange membrane as a proton permeating membrane. Several important factors on ammonia synthesis were investigated and the optimal synthetic temperature was found, at which the highest rate of evolution of ammonia was up to 1.05×10−8 mol·cm−2·s−1.
Spectroscopic Studies on the Binding of Bacteriophage Mequindox with Bovine Serum Albumin
Authors: ZENG Zhouhua , LIU Yi , HU Xianming , XU Zhenqiang , ZENG Kun
Published: May 2009

Fluorescence spectra and UV‐Vis absorption spectra have been used to study the binding of bacteriophage mequindox (MEQ) with bovine serum albumin (BSA), which performed a dynamic quenching process. The quenching constants and thermodynamic parameters at different temperatures were calculated. The binding was primarily driven by entropy, and hydrophobic forces also played a significant role. The distance between BSA and MEQ was estimated to be 4.5 nm based on the theory of F?rster's non‐radioactive energy transfer. Furthermore, synchronous fluorescence spectra and 3‐dimensional fluorescence spectra were used to figure out the configuration of BSA in the presence or absence of MEQ, which indicated that it was basically the same.
π Type Lithium Bond Interaction between Ethylene, Acetylene, or Benzene and Amido‐lithium
Authors: YUAN Kun , LIU Yanzhi , LÜ Lingling , ZHU Yuancheng , ZHANG Ji , ZHANG Junyan
Published: May 2009

The optimization geometries and interaction energy corrected by basis set super‐position error (BSSE) of the lithium bond complexes between ethylene, acetylene, or benzene and amido‐lithium have been calculated at the B3LYP/6‐311++G∗︁∗︁ and MP2/6‐311++G∗︁∗︁ levels. And only one configuration was obtained for each lithium bond system. All the equilibrium geometries were confirmed to be stable state by analytical frequency computations. The calculations showed that all the N(2)–Li(4) bond lengths increased obviously and the red shift of N(2)–Li(4) stretching frequency occurred after complexes formed. The calculated binding energies with BSSE and zero‐point vibrational energy corrections of complexes I, II and III are −26.04, −24.86 and −30.02 kJ·mol−1 via an MP2 method, respectively. Natural bond orbital (NBO) theory analysis revealed that the three complexes were all formed with π type lithium bond interaction between ethylene, acetylene, or benzene and amido‐lithium.
Adsorption of Methane on Water under Hydrate Formation Conditions
Authors: PENG Baozi , SUN Changyu , LIU Peng , CHEN Guangjin
Published: May 2009

The variation of interfacial tension with pressure has been determined systemically for water in equilibrium with compressed methane at temperature from 274.2 to 282.2 K in the range of pressure from 0.1 to 10.1 MPa using the pendant‐drop method. The results show that the interface tension decreased with increasing pressure when temperature was specified. Pressure has a great influence upon the interface tension at higher pressure. The surface excess concentrations of methane on water at different temperatures and pressures were calculated. The results showed that higher pressure and lower temperature corresponded to higher adsorption concentration of methane. At the same time, the surface adsorption free energies of methane were also calculated, indicating that the adsorption of methane on water under hydrate formation condition is more preferable than that at 298.2 K.
Activity Coefficients for NaBr in Aqueous D‐Trehalose/D‐Cellobiose Solutions at 298.15 K
Authors: ZHUO Kelei , WANG Wenhao , CHEN Yujuan , WANG Jianji
Published: May 2009

The ionic mean activity coefficients of NaBr in trehalose‐water and cellobiose‐water mixtures have been experimentally determined at 298.15 K from electrochemical potential measurements by an electrochemical cell containing two ion selective electrodes (ISE), together with the activity coefficients of the disaccharides. The parameters C1 representing the pair interactions between the disaccharides and NaBr have been obtained. The interactions of NaBr with trehalose, cellobiose and glucose were compared and discussed in terms of their difference in the stereo‐structures.
Preparation and Storage of Silver Nanoparticles in Aqueons Polymers
Authors: SONG Weihong , ZHANG Xiaoxiao , YIN Hongzong , SA Panpan , LIU Xiaoyan
Published: May 2009

Silver nanoparticles were obtained by a chemical reduction method using aqueous polymers as dispersant and characterized by UV‐Vis spectroscopy, transmission electron microscopy (TEM) and light‐scattering spectroscopy. Solid polymer films containing the silver nanoparticles were also prepared after evaporating the solvent, and then dried with existing polymer. The stability of the silver nanoparticles was compared between primary fresh silver nanoparticle solution and redissolved solid polymer films by UV‐Vis spectroscopy. The particle size ranged from 5 to 10 nm, and no obvious differences were found. Therefore, preparing solid nano‐Ag/polymer was a novel and useful method in storage of silver nanoparticles.
Monitoring of Methyldopa by Fast Fourier Transform Continuous Cyclic Voltammetry at Gold Microelectrode
Authors: NOROUZI Parviz , GANJALI Mohammad Reza , SHAHTAHERI Sayed Jamaleddin , DINARVAND Rasoul , HAMZEHPOOR Ali
Published: May 2009

A continuous cyclic voltammetric study of methyldopa at gold micro electrode was carried out. The drug in phosphate buffer (pH 2.0) is adsorpted at 400 mV, giving rise to change in the current of well‐defined oxidation peak of gold in the flow injection system. The proposed detection method has some of advantages, the greatest one of which are as follows: first, it is no more necessary to remove oxygen from the analyte solution and second, this is a very fast and appropriate technique for determination of the drug compound in a wide variety of chromatographic analysis methods. Signal‐to‐noise ratio has significantly increased by application of discrete Fast Fourier transform (FFT) method, background subtraction and two‐dimensional integration of the electrode response over a selected potential range and time window. Also in this work some parameters such as sweep rate, eluent pH, and accumulation time and potential were optimized. The linear concentration range was of 1.0×10−7−1.0×10−11 mol·L−1 (r=0.9975) with a limit of detection and quantitation 0.004 nmol·L−1 and 0.03 nmol·L−1, respectively. The method has the requisite accuracy, sensitivity, precision and selectivity to assay methyldopa in tablets. The influences of pH of eluent, accumulation potential, sweep rate, and accumulation time on the determination of the methyldopa were considered.
Controlled Synthesis and Characterization of Monodisperse Fe3O4 Nanoparticles
Authors: SHI Rongrong , GAO Guanhua , YI Ran , ZHOU Kechao , QIU Guanzhou , LIU Xiaohe
Published: May 2009

Monodisperse Fe3O4 nanoparticles were successfully synthesized through the thermal decomposition of iron acetylacetonate in octadecene solvent in the presence of oleic acid and oleylamine. The influences of experimental parameters, such as reacting temperature, amounts and kinds of surfactants, solvents, oleic acid and oleylamine, on the size and shape of monodisperse Fe3O4 nanoparticles were discussed. The phase structures, morphology, and size of the as‐prepared products were investigated in detail by X‐ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED) and high‐resolution transmission electron microscopy (HRTEM). Magnetic property was measured using a vibrating sample magnetometer (VSM) at room temperature, which revealed that Fe3O4 nanoparticles were of ferromagnetism with a saturation magnetization (Ms) of 74.0 emu/g and coercivity (Hc) of 72.6 Oe.
Determination of Epinephrine by Flow Injection Analysis Coupled Ag(III) Complex‐Luminol Chemiluminescence Detection
Authors: BAI Jiangbo , SHI Hongmei , ZHANG Yingze , TIAN Dehu , XU Xiangdong , KANG Weijun
Published: May 2009

A new Ag(III) complex‐luminol chemiluminescent system which was applied to the determination of epinephrine is firstly reported. Based on the enhancing effect of epinephrine on the chemiluminescence reaction of luminol with [Ag(HIO6)2]5− in alkaline solution, a highly sensitive chemiluminescence (CL) detection by flow injection analysis (FIA) was developed for epinephrine. Under the optimum conditions, CL intensity was proportional to concentration of epinephrine in the 1.0×10−9–1.0×10−7 mol·L−1 range. The limit of detection was 8.0×10−10 mol·L−1 for epinephrine (3δ), with a relative standard deviation (n=11) of 2.9% for 1.5×10−8 mol·L−1 epinephrine. The method validation was done with epinephrine determinations in commercial pharmaceutical products. The mechanism of the reactions was also discussed.
Separation of Aminobenzoic Acids by Gold Nanoparticle‐ modified Capillary Electrophoresis
Authors: YAN Hongtao , LI Tuo , GUO Yanli
Published: May 2009

A novel method for the separation of aminobenzoic acids by capillary electrophoresis was developed. The capillary was modified with gold nanoparticles. The effect of gold nanoparticles on the resolution and selectivity of separation was investigated. The influence of separation voltage, pH and buffer concentration on the separation of aminobenzoic acids was also examined. It was found that the presence of gold nanoparticles improved the precision of the analysis and increased the separation efficiency. Under the optimized experiment conditions, aminobenzoic acids were separated and determined. Linearity was established over the concentration range 0.5–40 µg·mL−1 with correlation coefficients of 0.9978–0.9992. The detection limits (S/N=3) were from 0.1 to 0.5 µg·mL−1.
Separation of Immunoglobulin in Conjunction with High Performance Liquid Chromatography Using Poly(vinyl ester resin) Monolith
Authors: YANG Guanqun , YANG Gengliang , LIU Haiyan , BAI Ligai , FENG Xiaojuan , YANG Xinru
Published: May 2009

Using vinyl ester resin both as the monomer and the crosslinker, 2,2‐azobis(2‐methylpropionitrile) (AIBN) as initiator, poly(vinyl ester resin) monolithic column was prepared to separate the immunoglobulin G (IgG) and yolk of eggs (IgY) from human plasma and egg yolk by HPLC respectively. The influence of concentration and pH of mobile phase on the chromatographic performance was investigated. Scanning electron microcopy showed that the poly(vinyl ester resin) monolithic stationary phase had a through‐pore structure. Dynamic capacity of IgG on the polymeric monolithic column was investigated. The monolithic column had good flow‐through properties and high resolution. The maximum adsorptive amount of IgG was 144 µg·g−1.
Facile Synthesis of 1,2,3,4‐Tetrahydrobenzo[b][1,8]‐naphthyridin‐2‐one via Baylis‐Hillman Adducts
Authors: CHEN Dongdong , XU Jing , YANG Chunhao , XIE Yuyuan
Published: May 2009

Various benzo[b][1,8]naphthyridin‐2‐ones were synthesized by a one‐pot tandem reduction‐double cyclization from the corresponding (Z)‐ethyl 4‐cyano‐5‐(2‐nitrophenyl)‐pent‐4‐enoates, which were easily prepared via Johnson‐Claisen rearrangement from Baylis‐Hillman affixtures of 2‐nitrobenzaldehydes. The procedure has the advantages of easy handling and seperation under mild and green conditions, and the overall yields are moderate.
Synthesis and Bioactivity of Some New 2‐(Alkoxy carbonyl alkyl)‐6‐bromo‐3,4‐dihydro‐3‐(α‐methyl benzyl)‐2‐oxo‐benzo[e] [2H‐1,3,2‐oxazaphosphinine] Derivatives
Authors: SRINIVASULU K. , SURESH KUMAR K. , HARI BABU B. , STEPHEN BABU M. F. , NAGA RAJU C. , SURESH REDDY C.
Published: May 2009

Synthesis of some new 2‐(alkoxy carbonyl alkyl)‐6‐bromo‐3,4‐dihydro‐3‐(α‐methyl benzyl)‐2‐oxo‐3‐benzo‐ [e][2H‐1,3,2‐oxazaphosphinine] derivatives was accomplished through a two step process, which involves the condensation of 2‐[(α‐methylbenzyl amino)methyl]‐4‐bromophenol (1) with phosphorus oxychloride in equimolar quantities in the presence of triethylamine in dry toluene in 50–55 °C producing the corresponding intermediate (2), and subsequent reaction with the amino acid alkyl ester in dry tetrahydrofuran in the presence of triethylamine at different temperatures. They exhibited significant antibacterial and fungal activity.
Preparation and Application of Perchloric Acid Supported on Alumina (Al2O3‐HClO4) to the Synthesis of α‐(α‐Amidobenzyl)‐β‐naphthols
Authors: SHATERIAN Hamid Reza , KHORAMI Fahimeh , AMIRZADEH Azita , GHASHANG Majid
Published: May 2009

Preparation of perchloric acid supported on alumina and its primary application as a solid supported heterogeneous catalyst to the synthesis of α‐(α‐amidobenzyl)‐β‐naphthols by a one‐pot, three‐component condensation of benzaldehydes, β‐naphthol and acetamide or benzamide under thermal solvent‐free conditions were described. The present methodology offers several advantages such as simple procedure, shorter reaction time, and excellent yields.
PPA‐SiO2 Catalyzed Multi‐component Synthesis of N‐[α‐(β‐Hydroxy‐α‐naphthyl)(benzyl)] O‐Alkyl Carbamate Derivatives
Authors: SHATERIAN Hamid Reza , HOSSEINIAN Asghar , GHASHANG Majid
Published: May 2009

Silica‐supported polyphosphoric acid (PPA‐SiO2) was found to be an efficient catalyst for the multi‐component condensation reaction of benzaldehydes, 2‐naphthol, and methyl/benzyl carbamate to afford the corresponding N‐[α‐(β‐hydroxy‐α‐naphthyl)(benzyl)] O‐alkyl carbamate derivatives in good to excellent yields. This new approach consistently has the advantage of short reaction time, high conversions, clean reaction profiles, and simple experimental and work‐up procedures.
Synthesis and Properties of Heteroacenes Containing Pyrrole and Thiazine Rings as Promising n‐Type Organic Semiconductor Candidates
Authors: HONG Wei , WEI Zhongming , XU Wei , WANG Quanrui , ZHU Daoben
Published: May 2009

PBBTZ (6H‐pyrrolo[3,2‐b:4,5‐b′]bis[1,4]benzothiazine) was a p‐type semiconductor with high field‐effect transistor (FET) performance that we have just reported. Two trifluoromethyl substituted PBBTZ derivatives 3a and 3b were synthesized from facile one‐pot condensation. They were characterized by means of 1H NMR, IR, HRMS (EI‐TOF) and elemental analysis, furthermore, the crystal structure of 3b was described and discussed. Their optical properties were studied by UV‐Vis and fluorescence spectroscopy, electrochemical properties were investigated by cyclic voltammetry (CV), and thermal properties were evaluated by thermal gravimetric analysis (TGA). The energy gaps of 3a and 3b, taken directly from spectroscopic measurements, are as broad as 2.45 and 2.48 eV, leading to bluish green and green photoluminescence. The LUMO and HOMO energy levels are −5.73 and −3.28 eV for 3a, −5.67 and −3.19 eV for 3b, respectively. The low energy levels render them well air‐stable, and to be promising n‐type semiconductor candidates for use in organic electronics.
Becoming stable and strong: The interplay between vinculin exchange dynamics and adhesion strength during adhesion site maturation
Authors: Möhl Christoph , Kirchgeßner Norbert , Schäfer Claudia , Küpper Kevin , Born Simone , Diez Gerold , Goldmann Wolfgang H. , Merkel Rudolf , Hoffmann Bernd
Published: May 2009

The coordinated formation and release of focal adhesions is necessary for cell attachment and migration. According to current models, these processes are caused by temporal variations in protein composition. Protein incorporation into focal adhesions is believed to be controlled by phosphorylation. Here, we tested the exchange dynamics of GFP‐vinculin as marker protein of focal adhesions using the method of Fluorescence Recovery After Photobleaching. The relevance of the phosphorylation state of the protein, the age of focal adhesions and the acting force were investigated. For stable focal adhesions of stationary keratinocytes, we determined an exchangeable vinculin fraction of 52% and a recovery halftime of 57 s. Nascent focal adhesions of moving cells contained a fraction of exchanging vinculin of 70% with a recovery halftime of 36 s. Upon maturation, mean saturation values and recovery halftimes decreased to levels of 49% and 42 s, respectively. Additionally, the fraction of stably incorporated vinculin increased with cell forces and decreased with vinculin phosphorylation within these sites. Experiments on a nonphosphorylatable vinculin mutant construct at phosphorylation site tyr1065 confirmed the direct interplay between phosphorylation and exchange dynamics of adhesion proteins during adhesion site maturation. Cell Motil. Cytoskeleton, 2009. © 2009 Wiley‐Liss, Inc.
Combined Strategies for the Discovery of Ionotropic Glutamate Receptor Antagonists
Authors: Chimirri Alba , De Luca Laura , Ferro Stefania , De Sarro Giovanbattista , Ciranna Lucia , Gitto Rosaria
Published: May 2009

New glutamate receptor ligands: This review describes the discovery of rationally designed AMPA and NMDA receptor antagonists, some of which have been proven to be highly potent anticonvulsant and neuroprotective agents.

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This review summarizes the results of our research group engaged in the development of new glutamate receptor ligands. Chemical and biological studies of several active molecules have been carried out. In particular, extensive work has addressed the identification of antagonists of AMPA and NMDA receptor subtypes using a combination of computational strategies. Innovative synthetic pathways have been used and small libraries of new molecules prepared. In vitro and in vivo tests were performed, and some compounds proved to be highly potent anticonvulsant and neuroprotective agents.