bluuebunny/crossref_metadata_2025 huggingface dataset:
An adjustment method of the number of states on Q‐learning segmenting state space adaptively
Authors: Hamagami Tomoki , Koakutsu Seiichi , Hirata Hironori
Published: August 2007

The results of imposing limitations on the number of states and of promoting the splitting of states in Q‐learning are presented. Q‐learning is a common reinforcement learning method in which the learning agent autonomously segments the environment states. In situations where the designer of an agent is unable to explicitly provide the agent with the boundaries of states in the environment in which the agent is acting, the agent needs to simultaneously learn while autonomously determining the internal discrete states that are needed in order to take the appropriate actions. A simple method of segmenting states based on a reinforcement signal (QLASS) has been proposed for this purpose. However, the original method suffers from the problem that the number of states grows excessively large as learning proceeds. A method is therefore proposed that defines temperature and eligibility attributes for each of the internal discrete states of the agent, and that limits and adds to the number of internal discrete states, and promotes random actions depending on the values of these attributes. The results of applying the proposed method to a number of tasks, including tasks that incorporate a dynamic environment, are compared to the QLASS method when only the reinforcement signal is used, and a similar level of learning results is found to be achieved using a fewer number of states. Furthermore, it is found that tasks are able to be completed in a small number of steps even when only a small number of trials are used for learning. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 90(9): 75– 86, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.20383
Learning of real robot's inverse dynamics by a forward‐propagation learning rule
Authors: Mori Hiroki , Ohama Yoshihiro , Fukumura Naohiro , Uno Yoji
Published: August 2007

A forward‐propagation learning rule (FPL) has been proposed for a neural network (NN) to learn an inverse model of a controlled object. A feature of FPL is that the trajectory error propagates forward in NN and appropriate values of two learning parameters are required to be set. FPL has only been simulated to several kinds of controlled objects such as a two‐link arm in a horizontal plane. In this work, we applied FPL to AIBO and showed the validity of FPL on a real controlled object. At first, we tested a learning experiment of an inverse dynamic of a two‐link arm in a sagittal plane with viscosity and Coulomb friction by computer simulation. In this simulation, a low‐pass filter (LPF) was applied to realized trajectories because coulomb friction vibrates them. From the simulation results, we found that the learning process is stable by some adequate sets of the learning parameters although it is more sensitive to the values of the parameters owing to friction and gravity terms. Finally, we tested applying FPL to motor control of AIBO's leg. The inverse dynamics model was acquired by FPL with only about 150 learning iterations. From these results, the validity of the FPL was confirmed by the real robot control experiments. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 161(4): 38–48, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20456
Quantum fluctuation in affine optimal control systems
Authors: Itami Teturo
Published: August 2007

Quantum mechanical wave functions are shown to approximate optimal feedback laws of affine control systems, when we set the absolute values of the terminal wave functions positive and with no singular dependence on a control constant HR, which is similar in position to the action constant $\hbar$ introduced by Planck to explain quantum phenomena. Calculation of the wave functions makes use of the path integral representation that we approximate at stationary phase. The phases of the wave functions approximate in HR→0 to Hamilton–Jacobi value functions, because quantum mechanical fluctuation vanishes in the limit. It is simple to take the terminal absolute value function that meets the condition of having no singularity at HR=0. The terminal absolute value function without any dependence on the constant HR apparently satisfies the no‐singularity condition. Although we restrict ourselves to scalar systems, generalization to systems with higher dimensionality is straightforward. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 161(4): 29–37, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20521
Propagation of inverter surge and voltage distribution in motor winding
Authors: Tsuji Kosei , Wada Kotaro , Muto Hirotaka , Otsuka Hisashi , Yashiro Osamu , Nagaoka Naoto
Published: August 2007

A new simulation technique was developed, which allows the estimation of motor winding voltages in inverter motor system. We developed a cable surge analysis method that takes into account the frequency‐dependent effect of the dielectric characteristics of the cable insulator and mutual induction between cable wires. A motor winding model that takes into consideration the frequency‐dependent effect of winding impedance and mutual coupling between slots is also proposed. With the simulation technique, motor winding voltages driven by an inverter are investigated, including propagation characteristics of a cable connecting the motor and the inverter. The accuracy of the proposed model is confirmed to be satisfactory enough for the estimation of winding voltages by comparisons between measured and calculated results. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 161(4): 70– 79, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20549
A method for designing CDO conformed to investment parameters
Authors: Nakae Tatsuya , Moritsu Toshiyuki , Komoda Norihisa
Published: August 2007

We propose a method for designing CDOs (Collateralized Debt Obligation) that meets investor needs regarding CDO attributes. It is demonstrated that adjusting the attributes (credit capability and issue amount) of CDOs to investors' preferences causes a capital loss risk that the agent takes. We formulate a CDO optimization problem by defining an objective function using the above risk and setting constraints that arise from investor needs and a risk premium that is paid for the agent. Our prototype experiment, in which fictitious underlying obligations and investor needs are given, verifies that CDOs can be designed without opportunity loss and dead stock loss, and that the capital loss is not more than a thousandth part of the amount of annual payment under guarantee for small and medium‐sized enterprises by a general credit guarantee institution. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 161(4): 20– 28, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20581
Performance analysis of the permanent‐magnet induction generator under unbalanced grid voltages
Authors: Tsuda Toshihiro , Fukami Tadashi , Kanamaru Yasunori , Miyamoto Toshio
Published: August 2007

This paper presents the electrical and magnetic characteristics of a permanent‐magnet induction generator (PMIG) under unbalanced grid voltages. The method of symmetrical components and two‐dimensional finite element analysis (2D‐FEA) are used to calculate these characteristics and the results are confirmed through experiments. Even if the voltage of the power grids is unbalanced, the PMIG can operate at high efficiency over a wide range of slip and the built‐in permanent‐magnet (PM) rotor is minimally affected by the negative‐sequence rotating field. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 161(4): 60–69, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20585
Search of target image area by using geometrical and gray‐level features
Authors: Matuura Yosihumi , Saitoh Fumihiko
Published: August 2007

This paper proposes a method to measure the two‐dimensional pose of an object by using voting process based on geometrical and gray‐level features between edge pixels and the base point. The proposed method can measure a location and an inclination of an object even if the object has a free pose in an image. In the template registration process, the geometrical features and the distribution of gray levels for all edge pixels are registered into the template table. In the matching process, not only the geometrical features but also the arrays of gray levels between the edge pixels and the base point are used for the matching. The experimental results show that the poses of objects with free locations and inclinations were recognized successfully by the proposed method. High‐speed matching was realized in comparison with the conventional methods. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 161(4): 12– 19, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20613
Conversion of CO2 into Formate by Homogeneously Catalyzed Hydrogenation in Water: Tuning Catalytic Activity and Water Solubility through the Acid–Base Equilibrium of the Ligand
Authors: Himeda Yuichiro
Published: August 2007

This Microreview focuses on the recently developed hydrogenation of CO2 and hydrogen carbonate catalyzed by half‐sandwich complexes with 4,4′‐dihydroxy‐2,2′‐bipyridine (dhbp) and 4,7‐dihydroxy‐1,10‐phenanthroline (dhpt). An unprecedented high catalytic activity and reusability of the catalyst without waste generation were achieved by automatic tuning of the catalytic activity and water solubility of the catalyst through the acid–base equilibrium of the catalyst ligand. The oxyanion generated from the phenol hydroxy group played significant roles in the electronic effect and polarity. The catalyst design concept and the excellent properties of the ligands are expected to have significantly broader implications for the design of new homogeneous catalysts.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Synthesis and Structure of Dinucleotides Featuring Canonical and Non‐canonical A‐Type Duplex α, β and δ Torsion Angle Combinations (LNA/α,β‐D‐CNA)
Authors: Dupouy Christelle , Lavedan Pierre , Escudier Jean‐Marc
Published: August 2007

The synthesis of diastereoisomers of LNA/α,β‐D‐CNA dinucleotide building units of nucleic acids in which one δ torsional angle is constrained by an LNA structure and the α and β torsional angles are stereocontrolled by a dioxaphosphorinane ring structure (D‐CNA family) is described. NMR structural analysis showed that the δa, αb and βb torsional angles of the (RC5′,RP)‐configured LNA/α,β‐D‐CNA TT dimer are restricted to the canonical {δa,αb,βb} = {gauche(+)/anticlinal(+), gauche(–), trans} conformation typically observed in A‐type duplexes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
The Ritter Reaction under Truly Catalytic Brønsted Acid Conditions
Authors: Sanz Roberto , Martínez Alberto , Guilarte Verónica , Álvarez‐Gutiérrez Julia M. , Rodríguez Félix
Published: August 2007

Simple organic acids like 2,4‐dinitrobenzenesulfonic acid (DNBSA) catalyze the Ritter reaction of secondary benzylic alcohols giving rise to the corresponding N‐benzylacetamides in usually high yields. Reactions can be conducted without exclusion of oxygen and without the need of dry solvents. With tertiary α,α‐dimethylbenzylic alcohols a different pathway involving a formal dimerization reaction takes place under the acid‐catalytic conditions used. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
A semiparametric method for predicting bankruptcy
Authors: Hwang Ruey‐Ching , Cheng K. F. , Lee Jack C.
Published: August 2007

Bankruptcy prediction methods based on a semiparametric logit model are proposed for simple random (prospective) and case–control (choice‐based; retrospective) data. The unknown parameters and prediction probabilities in the model are estimated by the local likelihood approach, and the resulting estimators are analyzed through their asymptotic biases and variances. The semiparametric bankruptcy prediction methods using these two types of data are shown to be essentially equivalent. Thus our proposed prediction model can be directly applied to data sampled from the two important designs. One real data example and simulations confirm that our prediction method is more powerful than alternatives, in the sense of yielding smaller out‐of‐sample error rates. Copyright © 2007 John Wiley & Sons, Ltd.
Forecasting volatility by means of threshold models
Authors: Muñoz M. Pilar , Marquez M. Dolores , Acosta Lesly M.
Published: August 2007

The aim of this paper is to compare the forecasting performance of competing threshold models, in order to capture the asymmetric effect in the volatility. We focus on examining the relative out‐of‐sample forecasting ability of the SETAR‐Threshold GARCH (SETAR‐TGARCH) and the SETAR‐Threshold Stochastic Volatility (SETAR‐THSV) models compared to the GARCH model and Stochastic Volatility (SV) model. However, the main problem in evaluating the predictive ability of volatility models is that the ‘true’ underlying volatility process is not observable and thus a proxy must be defined for the unobservable volatility. For the class of nonlinear state space models (SETAR‐THSV and SV), a modified version of the SIR algorithm has been used to estimate the unknown parameters. The forecasting performance of competing models has been compared for two return time series: IBEX 35 and S&P 500. We explore whether the increase in the complexity of the model implies that its forecasting ability improves. Copyright © 2007 John Wiley & Sons, Ltd.
Effect of olanzapine on cognition during treatment of behavioral and psychiatric symptoms in patients with dementia: a post‐hoc analysis
Authors: Deberdt Walter G. , Siegal Alan , Ahl Jonna , Meyers Adam L. , Landbloom Ronald
Published: August 2007

Objective

This study was conducted to determine the effect of olanzapine treatment on cognition in elderly patients with behavioral and psychiatric symptoms (BPSD) associated with dementia.

Methods

This was a post‐hoc analysis of three randomized double‐blind, clinical trials of olanzapine (n = 682) vs placebo (n = 257) in dementia patients with BPSD in long‐term or continuing‐care settings. One study was 6 weeks long; the other two were 10 weeks duration, and their data were combined. Patients were subgrouped according to baseline Mini Mental State Examination (MMSE) scores: Group I = 23–26; Group II = 19–22; Group III = 14–18; Group IV = 7–13; Group V = 1–6. BPSD was assessed by the Neuropsychiatric Inventory (NPI).

Results

Within‐treatment group cognitive decline in patients was significant in the combined studies, but not in the 6‐week study. Between‐treatment cognitive changes were non‐significant in the 6‐week study, but showed a statistical trend in the combined studies (olanzapine, −0.78 ± 0.19 vs placebo, −0.32 ± 0.25; p = 0.06). In the subgroup analysis, there was a significant between‐treatment difference in cognitive changes in MMSE subgroup IV in the combined studies (olanzapine, −0.63 ± 0.26 vs placebo, 0.27 ± 0.41, p = 0.04). Improvement in BPSD was correlated with better cognitive outcome (r = −0.2; p < 0.01).

Conclusions

Although the overall differences in cognitive changes in patients treated with olanzapine vs placebo were small and non‐significant, negative effects on cognition in some patients cannot be excluded, especially in patients with more pronounced cognitive decline or whose behavioral and psychiatric symptoms are not responding to treatment. Copyright © 2007 John Wiley & Sons, Ltd.
Cortical dynamics of word recognition
Authors: Mainy Nelly , Jung Julien , Baciu Monica , Kahane Philippe , Schoendorff Benjamin , Minotti Lorella , Hoffmann Dominique , Bertrand Olivier , Lachaux Jean‐Philippe
Published: August 2007

While functional neuroimaging studies have helped elucidate major regions implicated in word recognition, much less is known about the dynamics of the associated activations or the actual neural processes of their functional network. We used intracerebral electroencephalography recordings in 10 patients with epilepsy to directly measure neural activity in the temporal and frontal lobes during written words' recognition, predominantly in the left hemisphere. The patients were presented visually with consonant strings, pseudo‐words, and words and performed a hierarchical paradigm contrasting semantic processes (living vs. nonliving word categorization task), phonological processes (rhyme decision task on pseudo‐words), and visual processes (visual analysis of consonant strings). Stimuli triggered a cascade of modulations in the gamma‐band (>40 Hz) with reproducible timing and task‐sensitivity throughout the functional reading network: the earliest gamma‐band activations were observed for all stimuli in the mesial basal temporal lobe at 150 ms, reaching the word form area in the mid fusiform gyrus at 200 ms, evidencing a superiority effect for word‐like stimuli. Peaks of gamma‐band activations were then observed for word‐like stimuli after 400 ms in the anterior and middle portion of the superior temporal gyrus (BA 38 and BA 22 respectively), in the pars triangularis of Broca's area for the semantic task (BAs 45 and 47), and in the pars opercularis for the phonological task (BA 44). Concurrently, we observed a two‐pronged effect in the prefrontal cortex (BAs 9 and 46), with nonspecific sustained dorsal activation related to sustained attention and, more ventrally, a strong reflex deactivation around 500 ms, possibly due to semantic working memory reset. Hum Brain Mapp, 2008. © 2007 Wiley‐Liss, Inc.
Dynamics of event‐related causality in brain electrical activity
Authors: Korzeniewska Anna , Crainiceanu Ciprian M. , Kuś Rafał , Franaszczuk Piotr J. , Crone Nathan E.
Published: August 2007

A new method (Event‐Related Causality, ERC) is proposed for the investigation of functional interactions between brain regions during cognitive processing. ERC estimates the direction, intensity, spectral content, and temporal course of brain activity propagation within a cortical network. ERC is based upon the short‐time directed transfer function (SDTF), which is measured in short EEG epochs during multiple trials of a cognitive task, as well as the direct directed transfer function (dDTF), which distinguishes direct interactions between brain regions from indirect interactions via brain regions. ERC uses new statistical methods for comparing estimates of causal interactions during prestimulus “baseline” epochs and during poststimulus “activated” epochs in order to estimate event‐related increases and decreases in the functional interactions between cortical network components during cognitive tasks. The utility of the ERC approach is demonstrated through its application to human electrocorticographic recordings (ECoG) of a simple language task. ERC analyses of these ECoG recordings reveal frequency‐dependent interactions, particularly in high gamma (>60 Hz) frequencies, between brain regions known to participate in the recorded language task, and the temporal evolution of these interactions is consistent with the putative processing stages of this task. The method may be a useful tool for investigating the dynamics of causal interactions between various brain regions during cognitive task performance. Hum Brain Mapp 2008. © 2007 Wiley‐Liss, Inc.
Prone positioning for head and neck reconstructive surgery
Authors: Mobley Steven Ross , Miller Brian Thomas , Astor Frank C. , Fine Bradley , Halliday N. James
Published: August 2007

Certain head and neck surgical cases require the patient to be positioned prone. Such positioning carries with it an attendant subset of risks and complications not otherwise encountered in more traditional supine positioning. Gaining awareness of these risks and complications, and developing proactive positioning strategies, will enable the surgical team to position the patient optimally for the procedure and provide for every consideration of patient safety.

This article consists of a specific literature review of those issues directly related to the anatomical and physiological concerns arising from prone positioning. Particular attention is paid to the cardiopulmonary, renal, ophthalmologic, and neurological vulnerabilities unique to this position.

Proper planning by the surgical team and utilization of the correct equipment are a necessity. A tailored approach to the needs of the individual patient and an intimate awareness of the potential pitfalls will contribute to better outcomes when using the prone position. © 2007 Wiley Periodicals, Inc. Head Neck, 2007
Dissection of the submuscular recess (sublevel IIb) in squamous cell cancer of the upper aerodigestive tract: Prospective study and systematic review of the literature
Authors: Paleri Vinidh , Kumar Subramaniam Selva , Oozeer Nashreen , Rees Guy , Krishnan Suren
Published: August 2007

Background.

Selective neck dissection is commonly used to clear occult neck metastases in the N0 neck. The aim of this study was to identify the incidence of occult metastases in lymph nodes of sublevel IIb (submuscular recess; SMR) in upper aerodigestive tract squamous cell carcinoma in the setting of clinically and radiologically staged N0 necks and to perform a systematic review of the literature on the incidence of metastases in this setting.

Methods.

We conducted a prospective study of 50 neck dissections and systematic review of the literature.

Results.

(A) Prospective study: Tissue dissected out from the SMR was sent separately for histopathologic analysis. Between 0 and 7 nodes were harvested from sublevel IIb. One patient had a metastatic node in sublevel IIb with extracapsular spread in the ipsilateral neck. No other positive nodes were detected. Sixteen necks showed occult metastases at other levels. (B) Systematic review: The review identified 14 articles with 903 necks suitable for inclusion. The overall incidence of metastatic disease at this sublevel in the context of an N0 neck from any site is 2.0% (18 of 903). The incidence of occult metastatic disease in sublevel IIb for oral cavity, oropharyngeal, and laryngeal cancer is 3.9% (11 of 279), 5.2% (5 of 96), and 0.4% (1 of 230) patients, respectively. Contralateral positive nodes (0.9%) and isolated metastases (0.3%) at this sublevel were rare.

Conclusion.

Nodal metastases are uncommon in the SMR even in the presence of positive nodes in adjacent sublevel IIa. There appears to be no advantage in performing contralateral SMR dissection in N0 necks and in laryngeal primaries. © 2007 Wiley Periodicals, Inc. Head Neck, 2008
Total Synthesis of Murrayanine Involving 4,5‐Dimethyleneoxazolidin‐2‐ones and a Palladium(0)‐Catalyzed Diaryl Insertion
Authors: Bernal Pablo , Tamariz Joaquín
Published: August 2007

A new total synthesis of the natural carbazole murrayanine (1) was developed by using the 4,5‐dimethyleneoxazolidin‐2‐one 12 as starting material. The latter underwent a highly regioselective Diels–Alder cycloaddition with acrylaldehyde (=prop‐2‐enal; 13) to give adduct 14 (Scheme 3). Conversion of this adduct into diarylamine derivative 9 was carried out via hydrolysis and methylation (Scheme 4). Differing from our previous synthesis, in which such a diarylamine derivative was transformed into 1 by a PdII‐stoichiometric cyclization, this new approach comprised an improved cyclization through a more efficient Pd0‐catalyzed intramolecular diaryl coupling which was applied to 9, thus obtaining the natural carbazole 1 in a higher overall yield.
Iridoid Glucosides from Eremostachys moluccelloidesBunge
Authors: Çalış İhsan , Güvenç Ayşegül , Armağan Metin , Koyuncu Mehmet , Gotfredsen Charlotte H. , Jensen Søren R.
Published: August 2007

From the aerial parts of Eremostachys moluccelloides Bunge, a new iridoid glucoside, lamalbidic acid (7), was isolated as its choline salt 7a together with six known iridoid glucosides, 5‐deoxysesamoside (1), 6β‐hydroxy‐7‐epiloganin (2), lamalbide (3), shanzhiside methyl ester (4), sesamoside (5), and 5‐deoxypulchelloside I (6). The structures of 7a and 7 (obtained from 7a) were elucidated by spectroscopic (UV, IR, 1D‐ and 2D‐NMR, and ESI‐MS) methods.
Three New Neolignans from the Aril of Myristica fragrans
Authors: Li Fei , Yang Xiu‐Wei
Published: August 2007

Three new neolignans, named 1‐deoxycarinatone (1), isodihydrocarinatidin (2), and isolicarin A (3), together with the known neolignan (+)‐dehydrodiisoeugenol (4), were isolated from mace (the aril of Myristica fragrans Houtt.). Their structures were elucidated as 2‐[(1S)‐2‐(4‐hydroxy‐3‐methoxyphenyl)‐1‐methylethyl]‐6‐methoxy‐4‐(prop‐2‐enyl)phenol (1), 4‐[(2R,3R)‐2,3‐dihydro‐7‐methoxy‐3‐methyl‐5‐(prop‐2‐enyl)benzofuran‐2‐yl]‐2‐methoxyphenol (2), and 4‐{(2S,3R)‐2,3‐dihydro‐7‐methoxy‐3‐methyl‐5‐[(1E)‐prop‐1‐enyl]benzofuran‐2‐yl}‐2‐methoxyphenol (3) on the basis of spectroscopic data.
Solvent‐Free One‐Pot Synthesis of Amidoalkyl Naphthols Catalyzed by Silica Sulfuric Acid
Authors: Srihari Galla , Nagaraju Manda , Murthy Madugula Marthanda
Published: August 2007

An efficient, inexpensive, and mild method for the synthesis of amidoalkyl naphthols, catalyzed by ‘silica sulfuric acid’ (SSA), was elaborated under solvent‐free conditions at room temperature. Various amidoalkyl naphthols were synthesized in high yields from aromatic or aliphatic aldehydes, α‐ or β‐naphthols, and amides or urea or thiourea.
New Cadinane‐Type Sesquiterpenes from the Roots of Taiwania cryptomerioidesHayata
Authors: Chyu Chiou‐Fung , Ke Mei‐Ru , Chang Yuan‐Shiun , Chien Shih‐Chang , Kuo Yueh‐Hsiung
Published: August 2007

Six new cadinane‐type sesquiterpenes, (1β,4β,5α,10α)‐1,4‐epoxymuurolan‐5‐ol (1), (4α,10β)‐4,10‐dihydroxycadin‐1(6)‐en‐5‐one (2), (2β,3α,4β,6β)‐2,3‐dihydroxycadin‐1(10)‐en‐5‐one (3), (2β,3α)‐α‐corocalene‐2,3‐diol (4), (7S)‐α‐calacoren‐14‐ol (5), and (8β,9β,10β)‐8,9‐epoxycalamenene‐3,10‐diol (6) together with one known compound, (8β,9β,10β)‐8,9‐epoxycalamenen‐10‐ol (7), were isolated from the roots of Taiwania cryptomerioides. The structures of the new constituents were essentially elucidated by spectral evidence.
Phase Analysis of the Binary System of Cryolite (Na3AlF6) and Sodium Metasilicate (Na2SiO3)
Authors: Šimko František , Boča Miroslav
Published: August 2007

The phase analysis of cryolite (Na3AlF6) and sodium metasilicate (Na2SiO3) was performed by thermal analysis. The eutectic system with a region of two immiscible substances at a concentration of Na2SiO3 between 42.8 and 46.3 mol‐% was identified and the eutectic temperature determined to (886±2) °C. Based on the results of mass‐loss measurements, it was assumed that the introduced Na2SiO3 reacts with Na3AlF6 due to the formation of some nonvolatile stable compounds. The stable reaction products were identified by X‐ray diffraction analysis and IR spectroscopy of the spontaneously cooled samples, which established the formation of NaF and stable amorphous aluminosilicate compounds.
Physicochemical Properties of a New Multicomponent Cosolvent System for the pKa Determination of Poorly Soluble Pharmaceutical Compounds
Authors: Box Karl J. , Völgyi Gergely , Ruiz Rebeca , Comer John E. , Takács‐Novák Krisztina , Bosch Elisabeth , Ràfols Clara , Rosés Martí
Published: August 2007

A mixture of cosolvents is described that significantly improves the solubility of most pharmaceutical compounds. The mixture consists of equal volumes of MeOH, 1,4‐dioxane, and MeCN, thereby containing polar and nonpolar solvents, and is referred to as MDM (from MeOH, dioxane, and MeCN). MDM is mixed with H2O until the required composition is reached. The utility of this system is that it enables analytical measurements to be performed on a wide range of compounds where measurements would be impaired in aqueous solution. We present the physicochemical characteristics of MDM/H2O mixtures (density, dielectric constant, psKw) and the principles of pKa measurement in this solvent/H2O mixture. We also present pKa values in H2O of several drug compounds determined from values measured in MDM/H2O mixtures.
Two New, 1‐Oxygenated ent‐Kaurane‐Type Diterpenes from Croton kongensis
Authors: Chen Wei , Yang Xiao‐Dong , Zhao Jing‐Feng , Zhang Hong‐Bin , Li Liang
Published: August 2007

One new ent‐8,9‐secokaurane diterpene, kongensin D (1), and one new ent‐kaurane diterpene, kongensin E (2), along with one known compound, (7α)‐7,18‐dihydroxy‐ent‐kaur‐16‐en‐15‐one 18‐acetate (3), were isolated from the aerial parts of Croton kongensis. The structures of the new compounds were elucidated by means of HR‐MS and in‐depth NMR experiments, and by comparison with literature data. Compounds 1 and 2 showed an unusual oxygenation pattern with an OH or AcO group at C(1).
A New Pregnane and a New Diphenylmethane from the Root Barks of Periploca sepium
Authors: Wang Lei , Yin Zhi‐Qi , Shen Wen‐Bin , Zhang Qing‐Wen , Ye Wen‐Cai
Published: August 2007

A new polyoxygenated pregnane genin and a new diphenylmethane, along with five known pregnane derivatives, were isolated from the root barks of Periploca sepium. The structures of the new compounds were elucidated as (3β,14β)‐3,14‐dihydroxy‐21‐methoxypregn‐5‐en‐20‐one (1) and 2‐hydroxy‐5‐(2‐hydroxy‐4‐methoxybenzyl)‐4‐methoxybenzaldehyde (2) on the basis of spectroscopic methods, especially 2D‐NMR and MS analyses. The known compounds were identified by comparing their physical and spectroscopic data with those reported in the literature.
Cadinane and Eudesmane Sesquiterpenoids from Chloranthus henryi
Authors: Wu Bin , He Shan , Wu Xiao‐Dan , Wu De‐Kang , Pan Yuan‐Jiang
Published: August 2007

Chemical investigation of the leaves and stems of Chloranthus henryi resulted in the isolation and characterization of the three new cadinane‐type sesquiterpenes 1–3 and of the new eudesmane‐type sesquiterpene 4, together with three known compounds. Among the new compounds, the two cadinane‐type sesquiterpenes 1 and 2 possess an unusual aromatic ring B in their molecule. These structures were established on the basis of spectroscopic evidence. In addition, antitumor activities of the isolates were also evaluated.
Three New Clerodane Diterpenoids from the Bulbils of Dioscorea bulbifera L. var. sativa
Authors: Teponno Rémy Bertrand , Tapondjou Azefack Léon , Ju‐Jung Hyun , Nam Jung‐Hwan , Tane Pierre , Park Hee‐Juhn
Published: August 2007

From the bulbils of Dioscorea bulbifera L. var. sativa, three new clerodane diterpenoids, bafoudiosbulbin C (=methyl (2β,8α,12S)‐17‐oxo‐2,19 : 8,19 : 12,17 : 15,16‐tetraepoxycleroda‐3,13(16), 14‐triene‐18‐carboxylate; 1), bafoudiosbulbin D (=methyl (2β,6β,12R)‐17,19‐dioxo‐2,19 : 6,17 :  8,12 : 15,16‐tetraepoxycleroda‐13(16),14‐diene‐18‐carboxylate; 2), and bafoudiosbulbin E (=methyl (2β,3α,4α,6β,12R)‐17,19‐dioxo‐2,19 : 3,4 : 6,17 : 8,12 : 15,16‐pentaepoxycleroda‐13(16),14‐diene‐18‐carboxylate; 3) were isolated, together with the known compounds bafoudiosbulbins A and B, 3‐O‐β‐D‐glucopyranosyl‐β‐sitosterol, and 6′‐stearoyl‐3‐O‐β‐D‐glucopyranosyl‐β‐sitosterol. Their structures were established by high‐field NMR techniques (1H,1H‐COSY, 13C‐DEPT, HSQC, HMBC, and NOESY), MS analyses, as well as by comparison of their spectral data with those of related compounds.
Thioreductones and Derivatives (G)
Authors: Schank Kurt , Bügler Stephan , Folz Harald , Schott Norbert
Published: August 2007

Thioreductones and Derivatives. Replacement of one or two (principally also three) O‐atoms in aci‐reductones by sulfur leads to the corresponding thioreductones. In the present paper, different methods of their synthesis are discussed. Substitution of the bromo nucleofug in the 2‐position of 1,3‐dicarbonyl compounds as well as of a 3‐oxosulfone by selected sulfur nucleophiles is assumed to follow an SRN1 pathway. Characteristic properties, some typical reactions, and selected derivatives were studied. S‐Alkyl‐ and S‐aryl‐substituted cyclic 2‐thioreductones have been found to be synthons for the preparation of vinylogous reductones (2,3‐diacyl‐1,4‐dihydroxy‐1,3‐dienes) and of tetraacyl ethylenes as their bis‐dehydro products.
Management initiatives in a community‐based health insurance scheme
Authors: Sinha Tara , Ranson M. Kent , Chatterjee Mirai , Mills Anne
Published: August 2007

Community‐based health insurance (CBHI) schemes have developed in response to inadequacies of alternate systems for protecting the poor against health care expenditures. Some of these schemes have arisen within community‐based organizations (CBOs), which have strong links with poor communities, and are therefore well situated to offer CBHI. However, the managerial capacities of many such CBOs are limited. This paper describes management initiatives undertaken in a CBHI scheme in India, in the course of an action‐research project. The existing structures and systems at the CBHI had several strengths, but fell short on some counts, which became apparent in the course of planning for two interventions under the research project. Management initiatives were introduced that addressed four features of the CBHI, viz. human resources, organizational structure, implementation systems, and data management. Trained personnel were hired and given clear roles and responsibilities. Lines of reporting and accountability were spelt out, and supportive supervision was provided to team members. The data resources of the organization were strengthened for greater utilization of this information. While the changes that were introduced took some time to be accepted by team members, the commitment of the CBHI's leadership to these initiatives was critical to their success. Copyright © 2007 John Wiley & Sons, Ltd.
An observational study of the effectiveness and safety of intramuscular olanzapine in the treatment of acute agitation in patients with bipolar mania or schizophrenia/schizoaffective disorder
Authors: Centorrino Franca , Meyers Adam L. , Ahl Jonna , Cincotta Stephanie L. , Zun Leslie , Gulliver Angela H. , Kinon Bruce J. , Houston John P.
Published: August 2007

Objective

To determine the effect of intramuscular (IM) olanzapine in severely agitated patients.

Methods

This was an open‐label multicenter 1‐week observational study of IM olanzapine treatment in severely agitated inpatients and psychiatric emergency services with bipolar mania (n = 22) or schizophrenia (n = 52). Mean change from baseline to 2 h post‐first injection (LOCF) in agitation was assessed by PANSS‐Excited Component (PANSS‐EC) (score range: 5–35 points) mean change from baseline to 15, 30, 45, 60, 90, and 120 min post‐first injection, and visit‐wise mean changes from mixed‐model repeated measures analysis of variance. Kaplan–Meier survival curve analyses estimated time to categorical response (rating of ≤3 points each PANSS‐EC item).

Results

Two hours post‐injection of olanzapine (mean dose = 9.9 mg), patients exhibited mild calmness and agitation was significantly reduced by 19.2 ± 1.0 points (p < 0.001) (mean baseline = 29.0). Over 90% of the patients received only one injection in the first 24 h and 50% had a categorical response within 30 min.

Conclusions

Severely agitated patients responded rapidly after a single injection of olanzapine with mild levels of sedation and without serious treatment‐emergent adverse events. Copyright © 2007 John Wiley & Sons, Ltd.
Mapping correlated membrane pulsations and fluctuations in human cells
Authors: Pelling Andrew E. , Veraitch Farlan S. , Pui‐Kei Chu Carol , Nicholls Brian M. , Hemsley Alexandra L. , Mason Chris , Horton Michael A.
Published: August 2007

The cell membrane and cytoskeleton are dynamic structures that are strongly influenced by the thermo‐mechanical background in addition to biologically driven mechanical processes. We used atomic force microscopy (AFM) to measure the local membrane motion of human foreskin fibroblasts (HFFs) which were found to be governed by random and non‐random correlated mechanical processes. Interphase cells displayed distinct membrane pulsations in which the membrane was observed to slowly contract upwards followed by a recovery to its initial position. These pulsations occurred one to three times per minute with variable amplitudes (20–100 pN) separated by periods of random baseline fluctuations with amplitudes of <20 pN. Cells were exposed to actin and microtubule (MT) destabilizing drugs and induced into early apoptosis. Mechanical pulsations (20–80 pN) were not prevented by actin or MT depolymerization but were prevented in early apoptotic cells which only displayed small amplitude baseline fluctuations (<20 pN). Correlation analysis revealed that the cell membrane motion is largely random; however several non‐random processes, with time constants varying between ∼2 and 35 s are present. Results were compared to measured cardiomyocyte motion which was well defined and highly correlated. Employing automated positioning of the AFM tip, interphase HFF correlation time constants were also mapped over a 10 µm2 area above the nucleus providing some insights into the spatial variability of membrane correlations. Here, we are able to show that membrane pulsations and fluctuations can be linked to physiological state and cytoskeletal dynamics through distinct sets of correlation time constants in human cells. Copyright © 2007 John Wiley & Sons, Ltd.
The NTA–His6 bond is strong enough for AFM single‐molecular recognition studies
Authors: Verbelen Claire , Gruber Hermann J. , Dufrêne Yves F.
Published: August 2007

There is a need in current atomic force microscopy (AFM) molecular recognition studies for generic methods for the stable, functional attachment of proteins on tips and solid supports. In the last few years, the site‐directed nitrilotriacetic acid (NTA)–polyhistidine (Hisn) system has been increasingly used towards this goal. Yet, a crucial question in this context is whether the NTA–Hisn bond is sufficiently strong for ensuring stable protein immobilization during force spectroscopy measurements. Here, we measured the forces between AFM tips modified with NTA‐terminated alkanethiols and solid supports functionalized with His6‐Gly‐Cys peptides in the presence of Ni2+. The force histogram obtained at a loading rate of 6600 pN s−1 showed three maxima at rupture forces of 153 ± 57 pN, 316 ± 50 pN and 468 ± 44 pN, that we attribute primarily to monovalent and multivalent interactions between a single His6 moiety and one, two and three NTA groups, respectively. The measured forces are well above the 50–100 pN unbinding forces typically observed by AFM for receptor–ligand pairs. The plot of adhesion force versus log (loading rate) revealed a linear regime, from which we deduced a kinetic off‐rate constant of dissociation, koff ∼0.07 s−1. This value is in the range of that estimated for the multivalent interaction involving two NTA, using fluorescence measurements, and may account for an increased binding stability of the NTA–His6 bond. We conclude that the NTA–His6 system is a powerful, well‐suited platform for the stable, oriented immobilization of proteins in AFM single‐molecule studies. Copyright © 2007 John Wiley & Sons, Ltd.
Structure of an anti‐cholera toxin antibody Fab in complex with an epitope‐derived D‐peptide: a case of polyspecific recognition
Authors: Scheerer Patrick , Kramer Achim , Otte Livia , Seifert Martina , Wessner Helga , Scholz Christa , Krauß Norbert , Schneider‐Mergener Jens , Höhne Wolfgang
Published: August 2007

The structure of a complex of the anti‐cholera toxin antibody TE33 Fab (fragment antibody) with the D‐peptide vpGsqhyds was solved to 1.78 Å resolution. The D‐peptide was derived from the linear L‐peptide epitope VPGSQHIDS by a stepwise transformation. Despite the very similar amino acid sequence—the only difference is a tyrosine residue in position 7—there are marked differences in the individual positions with respect to their contribution to the peptide overall affinity as ascertained by a complete substitutional analysis. This is reflected by the X‐ray structure of the TE33 Fab/D‐peptide complex where there is an inverted orientation of the D‐peptide as compared with the known structure of a corresponding complex containing the epitope L‐peptide, with the side chains establishing different contacts within the binding site of TE33. The D‐ and L‐peptide affinities are comparable and the surface areas buried by complex formation are almost the same. Thus the antibody TE33 provides a typical example for polyspecific binding behavior of IgG family antibodies. Copyright © 2007 John Wiley & Sons, Ltd.
Effects of shade nettings, sowing time and storage on baby spinach flavonoids
Authors: Bergquist Sara ÅM , Gertsson Ulla E , Nordmark Lotta YG , Olsson Marie E
Published: August 2007

Flavonoids are important in plant interactions with the environment and may have positive effects on human health. Effects of light quality and quantity on flavonoid concentration were studied in baby spinach (Spinacia oleracea L.) cultivated under three types of shade netting differing in transmittance of UV‐B and PAR, at two times during the season. Leaves harvested at two growth stages for each sowing were subjected to different post‐harvest storage conditions. Shade nettings had a relatively small effect on flavonoid concentration in baby spinach. The largest effect was found when radiation was most intense. The nettings then decreased total flavonoid concentration by 15–24% at the normal commercial growth stage at harvest. Radiation and plant growth both affected flavonoid concentration, in opposite or similar directions depending on time of season. This variation was reflected in the statistical analysis, showing significant interactions among the factors. There were large differences (up to 100%) in flavonoid concentration between the different times of the season, in shaded as well as unshaded spinach. Flavonoid concentration and composition changed during storage, but no consistent difference was found between the shaded and unshaded leaves. In most cases, total flavonoid concentration increased significantly during the first 6 days of storage. In conclusion, the use of shade netting is acceptable for production of baby spinach as regards flavonoid concentration and composition. Copyright © 2007 Society of Chemical Industry
Infusions of Portuguese medicinal plants: Dependence of final antioxidant capacity and phenol content on extraction features
Authors: Gião Maria S , González‐Sanjosé Maria L , Rivero‐Pérez Maria D , Pereira Cláudia I , Pintado Manuela E , Malcata F Xavier
Published: August 2007

BACKGROUND: Aqueous extracts of most medicinal plants traditionally employed in Portugal (at the ratio of 1 g plant: 110 mL water) have been assayed for total antioxidant capacity and phenol content, in order to elucidate their claimed medicinal features.

RESULTS: The antioxidant activity was assessed by the ABTS•+ method; the ascorbic acid equivalent values ranged from 1.4280 ± 0.1261 g L−1 for avocado (Persea americana (Lauraceae)) obtained by infusion of powder, down to 0.0027 ± 0.0012 g L−1 for olive (Olea europaea (Oleaceae)) obtained by infusion of leaves. Total phenol content was determined by the Folin–Ciocalteu procedure; the gallic acid equivalent values ranged from 0.5541 ± 0.0289 g L−1 for avocado obtained by infusion of powder, down to 0.0053 ± 0.0014 g L−1 for olive obtained by boiling leaves. A good correlation between total antioxidant capacity and total phenol content was found.

CONCLUSION: The method of powder infusion should be chosen if high concentration of antioxidants are sought. On the other hand, a high antioxidant capacity and a high phenol content correlate well with the empirically established (and widely publicised) capacity to treat respiratory infections. Copyright © 2007 Society of Chemical Industry
Dough properties and breadmaking qualities of whole waxy wheat flour and effects of additional enzymes
Authors: Hung Pham Van , Maeda Tomoko , Fujita Masaya , Morita Naofumi
Published: August 2007

BACKGROUND: Waxy wheat, a new kind of genetically back‐crossed wheat, was applied to make whole bread in this study. Dough properties and bread quality of the whole waxy wheat flour, which was milled from 100% whole grains containing bran and germ, were determined.

RESULTS: Whole waxy wheat had lower protein and lipid contents but higher dietary fiber content than whole regular wheat flour. Pasting temperature and viscosity of the whole waxy wheat flour were significantly lower than those of the whole regular wheat. However, the white wheat flour milled from wheat grains with 48% recovery had significantly higher peak viscosity than the whole waxy wheat. Bread made from the whole waxy wheat flour was significantly softer than that from the whole regular wheat flour during storage. However, bread made from whole waxy wheat had significantly lower specific volume than that from the white waxy flour because of the high amount of dietary fiber. Addition of cellulase increased paste viscosity, lowered dough mixing properties and reduced the firmness of the bread. The addition of pentosanase also increased paste viscosity, lowered dough mixing properties, improved loaf volume of bread but increased the firmness of breadcrumbs, while the addition of α‐amylase only increased final viscosity of flour and did not affect dough properties and bread qualities of whole waxy wheat flour.

CONCLUSION: As a result, waxy wheat shows superior properties for making whole breads. Additional enzymes are also necessary to improve bread quality and nutritive values of whole waxy bread. Copyright © 2007 Society of Chemical Industry
Distribution of fatty acids in triacylglycerols and phospholipids from peas (Pisum sativum L.)
Authors: Yoshida Hiromi , Tomiyama Yuka , Tanaka Megumi , Mizushina Yoshiyuki
Published: August 2007

BACKGROUND: The fatty acid distribution of triacylglycerols (TAG) and major phospholipids (PL) obtained from four varieties of peas (Pisum sativum) was investigated. The total lipids extracted from the peas were separated by thin layer chromatography into seven fractions.

RESULTS: The major lipid components were PL (52.2–61.3%) and TAG (31.2–40.3%), while hydrocarbons, steryl esters, free fatty acids and diacylglycerols (sn‐1,3 and sn‐1,2) were also present in minor proportions (5.6–9.2%). The main PL components isolated from the four varieties were phosphatidylcholine (42.3–49.2%), phosphatidylinositol (23.3–25.2%) and phosphatidylethanolamine (17.7–20.5%). Significant differences (P < 0.05) in fatty acid distribution were found for different pea varieties. Phosphatidylinositol was unique in that it had the highest saturated fatty acid content among the three PL. However, the principal characteristics of the fatty acid distribution in the TAG and three PL were evident among the four varieties: unsaturated fatty acids were predominantly located in the sn‐2 position while saturated fatty acids primarily occupied the sn‐1 or sn‐3 position in the oils of the peas.

CONCLUSION: These results should be useful to both producers and consumers for the manufacture of pea foods in Japan. Copyright © 2007 Society of Chemical Industry