bluuebunny/crossref_metadata_2025 huggingface dataset:
The genetic basis of tooth development and dental defects
Authors: Thesleff Irma
Published: July 2006

More than 300 genes have so far been associated with tooth development, mainly in mouse embryos. The majority of them are associated with conserved signaling pathways mediating cellular communication, in particular between epithelial and mesenchymal tissues. Necessary functions of many signals, receptors and transcription factors have been demonstrated in mice, and mutations causing dental defects in humans have been identified in several genes. © 2006 Wiley‐Liss, Inc.
Evidence for an additional locus for split hand/foot malformation in chromosome region 8q21.11–q22.3
Authors: Gurnett Christina A. , Dobbs Matthew B. , Nordsieck Eric J. , Keppel Cassie , Goldfarb Charles A. , Morcuende Jose A. , Bowcock Anne M.
Published: July 2006

We identified a family where five members had nonsyndromic ectrodactyly. There were three known instances of nonpenetrance. Although four individuals had unilateral cleft hand, one individual had more severe, bilateral and asymmetric absence of the digits. None had foot abnormalities. After exclusion of linkage of SHFM in this family to five known loci, a genome wide scan was performed with DNA from 5 affected and 15 unaffected members of this family. Suggestive evidence for linkage of ectrodactyly to 8q was obtained on the basis of a maximum LOD score of 2.54 at theta (max) = 0 with GAAT1A4. Critical recombinants place the ectrodactyly gene in this family in a 16 cM (21 Mb) interval between D8S1143 and D8S556. Mutational analysis of two candidate genes (FZD6, GDF6) did not identify any mutations in affected members of this family. Our data indicate further genetic heterogeneity for ectrodactyly and suggest the presence of an additional SHFM locus in chromosome region 8q21.11–q22.3. © 2006 Wiley‐Liss, Inc.
PhenoChipping of psychotic disorders: A novel approach for deconstructing and quantitating psychiatric phenotypes
Authors: Niculescu Alexander B. , Lulow Len L. , Ogden Corey A. , Le‐Niculescu Helen , Salomon Daniel R. , Schork Nicholas J. , Caligiuri Michael P. , Lohr James B.
Published: July 2006

Psychiatric phenotypes as currently defined are primarily the result of clinical consensus criteria rather than empirical research. We propose, and present initial proof of principle for, a novel approach to characterizing psychiatric phenotypes. We have termed our approach PhenoChipping, by analogy with, and borrowing paradigms and tools from, gene expression microarray studies (GeneChipping). A massive parallel profiling of cognitive and affective state is done with a PhenoChip composed of a battery of existing and new quantitative psychiatric rating scales, as well as hand neuromotor measures. We present preliminary data from 104 subjects, 72 with psychotic disorders (bipolar disorder—41, schizophrenia—17, schizoaffective disorder—14), and 32 normal controls. Microarray data analysis software and visualization tools were used to investigate: 1. relationships between phenotypic items (“phenes”), including with objective motor measures, and 2. relationships between subjects. Our analyses revealed phenotypic overlap among, as well as phenotypic heterogeneity within, the three major psychotic disorders studied. This approach may be useful in helping us move beyond current diagnostic classifications, and suggests a combinatorial building‐block (Lego‐like) structure underlies psychiatric syndromes. The adaptation of microarray informatic tools for phenotypic analysis readily facilitates direct integration with gene expression profiling of lymphocytes in the same individuals, a strategy for molecular biomarker identification. Empirically derived clusterings of (endo)phenotypes and of patients will better serve genetic, pharmacological, and imaging research, as well as clinical practice. © 2006 Wiley‐Liss, Inc.
Down syndrome: Common otolaryngologic manifestations
Authors: Shott Sally R.
Published: July 2006

Otolaryngologic or ear, nose, and throat (ENT) problems are common in children with Down Syndrome (DS). This includes problems with chronic ear infections and chronic middle ear effusions with associated hearing loss, airway obstruction, and sleep apnea, as well as problems with chronic rhinitis and sinusitis. In addition, many of these ENT problems require surgical interventions, and there are special anesthesia considerations that need to be addressed in children with DS. These include subglottic stenosis, post‐operative airway obstruction, and cervical spine concerns. As the care of children with DS has become more consistent and proactive, outcomes from the treatment of these ENT manifestations have improved. Aggressive interventions, both medical and surgical, have led to a decreased incidence of hearing loss, good control of the chronic rhinitis, and a better awareness of the incidence of sleep apnea and sleep‐disordered breathing in individuals with DS. These common otolaryngologic manifestations of DS are reviewed with recommendations for ongoing care and monitoring. © 2006 Wiley‐Liss, Inc.
Clinical manifestations of hematologic and oncologic disorders in patients with Down syndrome
Authors: Dixon Natalia , Kishnani Priya S. , Zimmerman Sherri
Published: July 2006

Hematologic abnormalities are common in individuals with Down syndrome (DS). Increased erythrocyte mean corpuscular volume (MCV) is frequently found among DS infants and remains elevated throughout life in two‐thirds of patients, making interpretation of red cell indices for diagnosis of nutritional anemias or bone marrow failure disorders more challenging. Transient myeloproliferative disorder (TMD) associated with pancytopenia, hepatosplenomegaly, and circulating immature WBCs, is found almost exclusively in DS infants with an incidence of approximately 10%. In most cases, TMD regresses spontaneously within the first 3 months of life, but in some children, it can be life threatening or even fatal. Despite the high rate of spontaneous regression, TMD can be a preleukemic disorder in 20–30% of children with DS. The types of malignancy, response to therapy, and clinical outcome in children with DS are also unique. There is an increased risk of leukemia with an equal incidence of lymphoid and myeloid leukemia. Acute megakaryocytic leukemia (AMKL) subtype is the most common form of acute myeloid leukemia (AML) in this setting, and is uncommon in children without DS. Somatic mutations of the gene encoding the hematopoetic growth factorGATA1have been shown to be specific for TMD and AMKL in children with DS. Myelodysplastic syndrome can precede AML. Children with DS and leukemia are more sensitive to some chemotherapeutic agents such as methotrexate than other children which requires careful monitoring for toxicity. Although the risk for leukemia is higher in individuals with DS, these patients have a lower risk of developing solid tumors, with the exception of germ cell tumors, and perhaps retinoblastoma and lymphoma. © 2006 Wiley‐Liss, Inc.
The proteins of human chromosome 21
Authors: Gardiner Katheleen , Costa Alberto C.S.
Published: July 2006

Recent genomic sequence annotation suggests that the long arm of human chromosome 21 encodes more than 400 genes. Because there is no evidence to exclude any significant segment of 21q from containing genes relevant to the Down syndrome (DS) cognitive phenotype, all genes in this entire set must be considered as candidates. Only a subset, however, is likely to make critical contributions. Determining which these are is both a major focus in biology and a critical step in efficient development of therapeutics. The subtle molecular abnormality in DS, the 50% increase in chromosome 21 gene expression, presents significant challenges for researchers in detection and quantitation. Another challenge is the current limitation in understanding gene functions and in interpreting biological characteristics. Here, we review information on chromosome 21‐encoded proteins compiled from the literature and from genomics and proteomics databases. For each protein, we summarize their evolutionary conservation, the complexity of their known protein interactions and their level of expression in brain, and discuss the implications and limitations of these data. For a subset, we discuss neurologically relevant phenotypes of mouse models that include knockouts, mutations, or overexpression. Lastly, we highlight a small number of genes for which recent evidence suggests a function in biochemical/cellular pathways that are relevant to cognition. Until knowledge deficits are overcome, we suggest that effective development of gene–phenotype correlations in DS requires a serious and continuous effort to assimilate broad categories of information on chromosome 21 genes, plus the creation of more versatile mouse models. © 2006 Wiley‐Liss, Inc.
Breaking difficult news in a newborn setting: Down syndrome as a paradigm
Authors: Dent Karin M. , Carey John C.
Published: July 2006

Breaking the difficult news of an unexpected diagnosis to parents in the newborn setting is a common occurrence in genetic counseling. Many clinical geneticists and genetic counselors have had the challenge of delivering a postnatal diagnosis of Down syndrome to parents of newborns. Down syndrome is a common chromosome condition occurring in approximately 1 in 800 live births. Presenting the diagnosis to families must be accomplished in a supportive, positive, caring, and honest manner. However, there are few scientific data and little instruction in training programs on how best to convey this news in an appropriate manner. Several articles in the literature over the last three decades have proposed various guidelines for the so‐called informing interview. Discussions of parents' preferences and experiences in receiving this news have also been documented. Few reports, however, have focused on breaking difficult news of the diagnosis of a genetic condition to parents in a newborn setting in the genetics literature. In this paper, we will review the medical literature on delivering difficult news, specifically focused on that regarding the diagnosis of Down syndrome in the newborn setting. We propose a theoretical framework from which the informing interview can be planned and future outcome data can be measured. In this way, researchers of this theme can investigate the process, including the healthcare professionals' delivery of difficult news and make recommendations for continued improvement of the process. Our model can be generalized to breaking difficult news for a variety of other congenital conditions. © 2006 Wiley‐Liss, Inc.
Antinociceptive Effects of Synthetic Chalcones Obtained from Xanthoxyline
Authors: de Campos‐Buzzi Fátima , Pereira de Campos Jordana , Pozza Tonini Patrícia , Corrêa Rogério , Augusto Yunes Rosendo , Boeck Paula , Cechinel‐Filho Valdir
Published: July 2006

A wide variety of noxious stimuli are known to induce a sensation of pain evoked in a remote region of the body. Here, we show that chalcones can inhibit the pain provoked by the administration of an intraperitoneal acetic acid (AA). This study investigates the effects of 17 synthetic chalcones in the writhing test, a visceral pain model in mice. The majority of these compounds proved more active than some analgesic drugs, such as aspirin and acetaminophen, two reference drugs used here for comparison. Four chalcones, 9, 10, 16, and 17, were selected for more detailed studies, since they exhibited significant antinociceptive activities and chemical structures of interest. They caused dose‐related inhibitions, proving about 15‐, 10‐, 9‐, and 8‐fold more active than the standard drugs. When administrated orally, only chalcone 9 proved to be effective. These chalcones might be further used as a model to obtain new and more potent analgesic drugs.
Periodic Trends in the Agostic Interaction in Zirconium and Hafnium Methylidene Hydride Halide Complexes
Authors: Cho Han‐Gook , Kim Tae‐Hyun , Andrews Lester
Published: July 2006

The reactions of methyl chloride and bromide with laser‐ablated Zr and Hf atoms during deposition in excess Ne, Ar, or Kr are investigated, and the products are examined by matrix IR spectroscopy and density functional theory calculations. The methylidene complexes, [CH2MHX] (M=Zr and Hf, X=Cl and Br), are formed along with the methyl metal halide complexes, [CH3MX]. The amounts of both types of complexes increase upon photolysis and in the early stages of annealing. Two sets of methylidene absorptions observed in Ar and Kr matrices form a persistent photoreversible system. The most stable C1 and slightly higher energy planar structures of the methylidene complex in the singlet ground state trapped in the matrix reproduce the characteristics of the two sets of absorptions. Agostic distortion of the methylidene complexes decreases in the order Ti, Zr, Hf and increases in the order F, Cl, and Br; the CZr and ZrH stretching frequencies increase, and the bonds become shorter. This observation favors the characterization of the agostic interaction as a reorganization of charge.
How strongly do sequence conservation patterns and empirical scales correlate with exposure patterns of transmembrane helices of membrane proteins?
Authors: Park Yungki , Helms Volkhard
Published: July 2006

Given the difficulty in determining high‐resolution structures of helical membrane proteins, sequence‐based prediction methods can be useful in elucidating diverse physiological processes mediated by this important class of proteins. Predicting the angular orientations of transmembrane (TM) helices about the helix axes, based on the helix parameters from electron microscopy data, is a classical problem in this regard. This problem has triggered the development of a number of different empirical scales. Recently, sequence conservation patterns were also made use of for improved predictions. Empirical scales and sequence conservation patterns (collectively termed as “prediction scales”) have also found frequent applications in other research areas of membrane proteins: for example, in structure modeling and in prediction of buried TM helices. This trend is expected to grow in the near future unless there are revolutionary developments in the experimental characterization of membrane proteins. Thus, it is timely and imperative to carry out a comprehensive benchmark test over the prediction scales proposed so far to determine their pros and cons. In the current analysis, we use exposure patterns of TM helices as a golden standard, because if one develops a prediction scale that correlates perfectly with exposure patterns of TM helices, it will enable one to predict buried residues (or buried faces) of TM helices with an accuracy of 100%. Our analysis reveals several important points. (1) It demonstrates that sequence conservation patterns are much more strongly correlated with exposure patterns of TM helices than empirical scales. (2) Scales that were specifically parameterized using structure data (structure‐based scales) display stronger correlation than hydrophobicity‐based scales, as expected. (3) A nonnegligible difference is observed among the structure‐based scales in their correlational property, suggesting that not every learning algorithm is equally effective. (4) A straightforward framework of optimally combining sequence conservation patterns and empirical scales is proposed, which reveals that improvements gained from combining the two sources of information are not dramatic in almost all cases. In turn, this calls for the development of fundamentally different scales that capture the essentials of membrane protein folding for substantial improvements. © 2006 Wiley Periodicals, Inc. Biopolymers 83:389–399, 2006

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Study of variant anatomical structures (bony canals, fibrous bands, and muscles) in relation to potential supraclavicular nerve entrapment
Authors: Jelev L. , Surchev L.
Published: July 2006

Since the definition of supraclavicular nerve entrapment syndrome by Gelberman et al. (Gelberman et al. [1975] J. Bone Joint Surg. Am. 57:119) a number of clinical cases of this specific entrapment neuropathy have been reported. In all these cases, the nerve injury has been attributed to the location of the supraclavicular nerve branch in a narrow canal in the clavicle. However, in the anatomical literature, variations in the course of the supraclavicular nerves have not only been ascribed to bony canals but also to abnormal fibrous and muscular structures. Considering the fact that the existence of a narrow site with rigid walls along the course of a nerve is essential for the development of an entrapment neuropathy, our study examines all the variant anatomical structures with a possible role in supraclavicular nerve entrapment. We describe three groups of anatomical structures with close relation to the course of the supraclavicular nerves—transclavicular canals, fibrous bands, and unusual muscular structures. Based on the characteristics of the variations found, for the first time, we suggest that in addition to the bony canals through the clavicle certain fibrous and muscular structures could also be an anatomical basis for supraclavicular nerve entrapment syndrome. Clin. Anat. 20:278–285, 2007. © 2006 Wiley‐Liss, Inc.
Initial rotor position estimation of interior permanent magnet synchronous motor using optimal voltage vector
Authors: Tanaka Koji , Moriyama Rintaro , Miki Ichiro
Published: July 2006

The initial rotor position estimation is a serious problem affecting sensorless drives of permanent magnet synchronous motors. This paper presents an estimation method of initial rotor position for interior permanent magnet synchronous motors. The principle of the estimation is based on the nonlinear magnetization characteristics of the stator core caused by the magnet of the rotor. The estimation is performed using the variation of the current response caused by the magnetic saturation when the voltage vector is applied to the motor. This method can be performed without motor parameters and any additional hardware. Decision method of the optimal voltage vector applied to the motor is also proposed to accurately implement the estimation. Experimental results show that the initial rotor position can be estimated without rotating the rotor by using the optimal voltage vector. It is found that the average of the estimation error is ±1.34 electrical degrees, and the estimation is completed within 15.2 ms in the test motor. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 156(4): 69–76, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20062
Carrier phase error detection method and synchronization control of parallel‐connected PWM inverters without signal line
Authors: Kohara Tatsuya , Noguchi Toshihiko , Kondo Seiji
Published: July 2006

In recent years, parallel operation of inverters is employed to increase reliability and capacity in an uninterruptible power supply (UPS) system. A phase error in PWM carrier‐signals of each inverter causes high‐frequency loop current between inverters. Therefore, the PWM carrier‐signal of each inverter should be adjusted in phase.

This paper proposes a detection method of phase error in PWM carrier‐signal and its application to synchronization control for parallel‐connected inverters. A simple definite‐integral circuit achieves detection of the carrier phase error from high‐frequency loop current using no signal line between inverters. The detected carrier phase error is applied to synchronize the PWM carrier‐signal through a PI compensator, and then the high‐frequency loop current can be suppressed. Several experimental test results show the validity of the proposed detection method and synchronization control. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 157(1): 63– 71, 2006; Published online in Wiley InterScience (http://www.interscience.wiley.com). DOI 10.1002/eej.20143
Observation of lightning phenomena on distribution lines using composite techniques
Authors: Hirai Takao , Okabe Shigemitsu , Takinami Tsutomu , Chindo Takuji
Published: July 2006

For the rationalization of lightning protection design of distribution lines, it is important to clarify the behavior of distribution lines when direct or nearby lightning occurs. Because of the lower insulation level than for transmission lines, in studies on lightning protection design of distribution lines, not only direct lightning strokes but also induced voltages caused by nearby strokes must be taken into account. Thus, it is necessary to grasp the frequency of occurrence on lightning phenomena around distribution lines. For this aim, lightning phenomena on TEPCO's distribution lines in use had been continuously observed for 6 years (1996 to 2001). The observation was carried out in a composite way, using still cameras and sensor for acquisition of lightning surge waveform data. Through the observation, new phenomena about lightning performance on distribution lines in the field became apparent. In some cases, in spite of a direct strike to the line, flashover did not occur. This fact means that the distribution line has a certain level of lightning resistance. Moreover, it was confirmed that AC following current generated between both ends of insulator disappeared naturally. These results are interesting discoveries that can be useful in estimating the fault ratio precisely. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 157(1): 10–19, 2006; Published online in Wiley InterScience (http://www.interscience.wiley.com). DOI 10.1002/eej.20164
Control performance of single‐phase STATCOM and BTB by three‐level inverters
Authors: Tamai Shinzo , Akagi Hirofumi
Published: July 2006

The so‐called three‐level inverters have been widely used for industry applications because of high‐voltage output ability and low harmonic contents. These applications are mainly suitable for AC motor drives. Recent attention has been paid to larger‐capacity inverters applicable to power system control. This paper describes their applications to power systems. First, harmonic analysis of a three‐level inverter is achieved under the condition that its two DC capacitor voltage are unbalanced. Second, a control method for balancing the two DC capacitor voltages is described. Finally, applications of single‐phase three‐level inverters to STATCOM and BTB are introduced. Their control performance is confirmed by computer simulation. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 157(1): 54–62, 2006; Published online in Wiley InterScience (http://www.interscience.wiley.com). DOI 10.1002/eej.20306
A method for estimating initial pole position of surface permanent magnet synchronous motors using pulse voltage
Authors: Yamamoto Shu , Ara Takahiro
Published: July 2006

The initial pole position must be estimated for speed sensorless vector control of PM motors. This paper presents a method to estimate initial pole position for Surface Permanent Magnet Synchronous Motors (SPMSM). For estimating the initial pole position, we utilize Fourier transformation for detecting the inductance change caused by rotor magnetic saliency. The six inductances, obtained by Fourier transformation of the voltage and current measured when a pulse voltage is applied to the motor armature winding respectively, will directly provide the exact information of pole position. The polar distinction is also carried out using Fourier transformation on the basis of the inductance change caused by magnetic saturation. Experimental results on a 0.3‐kW 8‐pole SPMSM demonstrate the validity of the proposed method. Although no machine was coupled with the tested motor, there was no change in rotor position during pole position estimation. In polar distinction, the maximum rotor position change was only 1.38 electric degrees. A method to estimate initial pole position without a motor voltage sensor is also discussed. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 157(1): 47–53, 2006; Published online in Wiley InterScience (http://www.interscience.wiley.com). DOI 10.1002/eej.20307
An electric power purchase strategy for bilateral contracts focusing on reliability of customers
Authors: Niioka Satoru , Yokoyama Ryuichi
Published: July 2006

With the introduction of the competitive electrical power market, large‐scale customers can select electric power suppliers. Customers need to consider not only the economical efficiency but also reliability, to decide the amount of electrical power to purchase. This paper develops an economic electric power purchase strategy for customers focusing on reliability. A bilateral contract model expressing electric power suppliers as generators with a forced outage rate is proposed and introduced to assess potential outage risks of the bilateral contract between an electric power supplier and a customer. The outage‐related cost, consisting of potential outage risks and the estimated outage cost, is also proposed and introduced as an index of the reliability on the customer side, and an optimal reliability level of a customer is obtained by using the index. Several numerical examples demonstrate the availability of the proposed electric power purchase decision method and reliability improvement strategies for customers are discussed. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 156(4): 9–21, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20345
A study on lip extraction due to fuzzy reasoning by using color information
Authors: Shirasawa Yoichi , Nishida Makoto , Nishi Kenji
Published: July 2006

This paper proposes a method for extracting the lip shape from the region around the lips. It is carried out without limited conditions such as lipstick or lighting. The proposed method uses color information for the lip shape extraction. They are psychometric quantities of a metric hue angle (hab), rectangular coordinates (a*), which are defined in the CIE 1976 L*a*b* color space. The method employs fuzzy reasoning in order to consider obscurity in image data such as a shadow on the face. The conditional membership function for characteristics in each class was defined by the triangular membership function and was used for the fuzzy reasoning. In order to reduce the effect of the data acquisition conditions, an extraction method is here presented for the lip shape from the region around the lip through fuzzy reasoning. We studied the setup of the conditional membership function. The proposed method uses the a* color histogram and hab color histogram for the region around the lips when setting up the conditional membership function. This paper clarifies that the lip was able to be extracted without any special conditions such as lipstick or lighting. The experimental results indicate the effectiveness of the proposed method; about 98.7% of facial image data was extracted correctly. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 157(1): 20– 28, 2006; Published online in Wiley InterScience (http://www.interscience.wiley.com). DOI 10.1002/eej.20401
Unexpected features of acute T lymphoblastic lymphomas in Notch1IC transgenic rats
Authors: van den Brandt Jens , Kwon Soon‐Hwan , McPherson Kirsty G. , Petrovic Suzana , Zettl Andreas , Müller‐Hermelink Hans Konrad , Reichardt Holger M.
Published: July 2006

Dysregulated Notch signaling accounts for the majority of acute T lymphoblastic leukemia/lymphoma (T‐ALL) cases in humans. Here, we characterize lymphomas from Notch1IC transgenic rats, which develop T‐ALL shortly after weaning, and show that they display a number of previously undocumented features. Starting from monoclonal thymic tumors, the CD4+CD8αα+ lymphoma cells infiltrate the bone marrow and then spread to secondary lymphoid and non‐lymphoid organs. However, major hallmarks of T‐ALL cells in other murine models and human patients, such as constitutive NF‐κB activity and increased levels of anti‐apoptotic proteins, are remarkably absent in Notch1IC lymphomas. In contrast, CD30, a classic marker of Hodgkin lymphomas, is overexpressed in these tumors. Intriguingly, enforced Notch1 signaling up‐regulates expression of Notch3, which has also been implicated in the pathogenesis of T‐ALL. By blocking endogenous Notch signaling, we could demonstrate that Notch1IC is sufficient to induce sustained preTCR expression in transgenic thymocytes but not for their progression to the double‐positive stage. This suggests that other Notch activities may also contribute to the phenotype of the transgenic rats. In summary, we anticipate this new animal model will help to further elucidate the role of Notch1 in the pathogenesis of T‐ALL.
Ethyl Difluoro(trimethylsilyl)acetate and Difluoro(trimethylsilyl)acetamides – Precursors of 3,3‐Difluoroazetidinones
Authors: Bordeau Michel , Frébault Frédéric , Gobet Mallory , Picard Jean‐Paul
Published: July 2006

Difluoro(trimethylsilyl)acetamides 7 have been prepared from chlorodifluoroacetamides 5 by electrochemical silylation. When condensed with carbonyl compounds, they were shown to be precursors of 2,2‐difluoro‐3‐hydroxyacetamides 8. N‐(p‐Methoxyphenyl)‐2,2‐difluoro‐3‐hydroxy‐4‐methylvaleramide (8a) has been converted into the corresponding 3,3‐difluoroazetidinone 9a. This new route to 3,3‐difluoroazetidinones is shown to be an alternative to the one utilizing the condensation of ethyl difluoro(trimethylsilyl)acetate with imines. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Gold‐Catalyzed Hydroamination of C–C Multiple Bonds
Authors: Widenhoefer Ross A. , Han Xiaoqing
Published: July 2006

The development of general and efficient methods for the addition of an N–H bond across a C–C multiple bond (hydroamination) represents a significant challenge in both organic synthesis and homogeneous catalysis. Although a diverse range of transition‐metal complexes have been employed as catalysts for hydroamination, examples of gold‐catalyzed hydroamination were exceedingly rare prior to 2001. However, over the past five years gold complexes have been applied as catalysts for a number of selective organic transformations including the hydroamination of unactivated alkenes, alkynes, allenes, and 1,3‐dienes. This Microreview provides a brief overview of the gold‐catalyzed hydroamination of C–C multiple bonds. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Determination of association constants of inclusion complexes of steroid hormones and cyclodextrins from their electrophoretic mobility
Authors: Shakalisava Yuliya , Regan Fiona
Published: July 2006

CE estimation of the association constants of several steroid hormones with β‐CD and γ‐CD and their hydroxypropyl derivative is presented. Estriol, 17β‐estradiol, ethynylestradiol, estrone, progesterone, mestranol and norethindrone are among the target analytes. The calculation of the cyclodextrin:analyte association constants were performed from the electrophoretic mobility values of steroids at different concentration of CDs in the run buffer. The reliability of the final data was ensured by employing three different linearisation plots (double reciprocal fit, Y‐reciprocal fit and X‐reciprocal fit). The highest inclusion affinity of target analytes was observed towards γ‐CD and its hydroxypropyl derivative, which is demonstrated by high association constant values and corresponding good linearity of the plots. The affinity of steroids towards a particular CD type based on physical and structural characteristics is explored.
Cupric ion release controlled by copper/low‐density polyethylene nanocomposite in simulated uterine solution
Authors: Cai Shuizhou , Xia Xianping , Zhu Changhong , Xie Changsheng
Published: July 2006

The Cu2+ release rate of novel copper/low‐density polyethylene composites as an intrauterine device material in the simulated uterine solution was investigated for 280 days. The corrosion products of these composites were identified by the X‐ray diffraction method. The distributions of the copper phase and the cuprous oxide phase at different corrosion depths in the composites were measured by the internal standard method. For comparison, copper particles of two sizes were embedded in a polyethylene matrix to form composites. The average copper particle diameter of the nanocomposite was 30 nm, while that of microcomposite was 52 μm. Mechanism of Cu2+ release controlled by the nanocomposite revealed that many clusters composed of copper nanoparticles, which were observed by the field emission scanning electron microscopy in the nanocomposite, led to the formation of large amounts of Cu2O and consequently facilitated the Cu2+ steady release. A scanning electron microscope with energy dispersive X‐ray microanalysis mapping technique (SEM/EDX) was employed to measure the corrosion depth and to calculate the life span of the nanocomposite. The result that the nanocomposite displayed a near zero‐order release after a month of incubation indicated that the Cu2+ release behavior controlled by nanocomposite was remarkably superior to that by microcomposite. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
Polylactic acid–phosphate glass composite foams as scaffolds for bone tissue engineering
Authors: Georgiou G. , Mathieu L. , Pioletti D. P. , Bourban P.‐E. , Månson J.‐A. E. , Knowles J. C. , Nazhat S. N.
Published: July 2006

Phosphate glass (PG) of the composition 0.46(CaO)–0.04(Na2O)–0.5(P2O5) was used as filler in poly‐L‐lactic acid (PLA) foams developed as degradable scaffolds for bone tissue engineering. The effect of PG on PLA was assessed both in bulk and porous composite foams. Composites with various PG content (0, 5, 10, and 20 wt %) were melt‐extruded, and either compression‐molded or foamed through supercritical CO2. Dynamic mechanical analysis on the bulk composites showed that incorporating 20 wt % PG resulted in a significant increase in storage modulus. Aging studies in deionized water in terms of weight loss, pH change, and ion release inferred that the degradation was due to PG dissolution, and dependent on the amount of glass in the composites. Foaming was only possible for composites containing 5 and 10 wt % PG, as an increase in PG increased the foam densities; however, the level of porosity was maintained above 75%. PLA‐Tg in the foams was higher than those obtained for the bulk. Compressive moduli showed no significant reinforcement with glass incorporation in either expansion direction, indicating no anisotropy. Biocompatibility showed that proliferation of human fetal bone cells was more rapid for PLA compared to PLA‐PG foams. However, the proliferation rate of PLA‐PG foams were similar to those obtained for foams of PLA with either hydroxyapatite or β‐tricalcium phosphate. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
The elution of poly (vinyl alcohol) from a contact lens: The realization of a time release moisturizing agent/artificial tear
Authors: Winterton Lynn C. , Lally John M. , Sentell Karen B. , Chapoy L. Lawrence
Published: July 2006

The use of a contact lens as a polymeric delivery vehicle is presented. Specifically, the elution of nonfunctionalized poly (vinyl alcohol) (PVA) from nelfilcon A hydrogel lenses is presented as a model of delivering polymeric active agents to the eye. High molecular weight nonfunctionalized PVA is added to the lens matrix for later release into the tears. This is made possible by photo crosslinking a macromer species in lieu of monomeric polymerization. Consistent near zero order release of 0.062% (wt/wt) was demonstrated in vitro over a 20‐h period. The result is a new contact lens device based on the slow release of PVA. In vivo results demonstrate that this product improves the wearing comfort of this type of contact lens and acts as a model basis for drug delivery. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
Effect of crystallization heat treatment on the microstructure and biaxial strength of fluorrichterite glass‐ceramics
Authors: Denry I. L. , Holloway J. A.
Published: July 2006

The purpose of this study was to evaluate the effect of crystallization heat treatment on the flexural strength of potassium fluorrichterite glass‐ceramics for biomedical applications. After melting and casting, discs were sectioned from the glass ingots, randomly divided into 10 groups, and heat treated at various temperatures ranging between 890°C and 925°C for various durations. One group was air‐abraded after heat treatment. XRD revealed the presence of fluorrichterite and fluormica for all heat‐treated groups. SEM confirmed the presence of both fluorrichterite and fluormica crystals. Crystal size increased with temperature and duration of the heat treatment. The mean flexural strength after air abrasion was not significantly different than that of the other groups except the group heat treated at 925°C. The mean flexural strength was maximum after heat treatment at 900°C for 1 h (497.6 ± 25.5 MPa) and decreased linearly with the longer durations of heat treatment at 900°C. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
Induction of heme oxygenase‐1 expression by root canal sealers in human gingival fibroblasts is augmented by oxidative stress
Authors: Huang Fu‐Mei , Chang Yu‐Chao
Published: July 2006

Heme oxygenase‐1 (HO‐1) is known as a stress‐inducible protein and functions as an antioxidant enzyme. It has been shown that HO‐1 is induced rapidly by a variety of chemical and physical stimuli. However, little is known about the induction of cellular signaling events after cell exposure to root canal sealers. The aim of this study was to investigate the effects of zinc oxide‐eugenol‐based root canal sealer N2 and epoxy resin‐based root canal sealer Topseal on the expression of HO‐1 protein in cultured human gingival fibroblasts (HGFs). The results showed that both N2 and Topseal were cytotoxic to HGFs in a concentration‐dependent manner (p < 0.05). The exposure of quiescent HGFs to N2 and Topseal resulted in the induction of HO‐1 protein expression in a time‐dependent manner (p < 0.05). Furthermore, to determine whether oxidative stress could modulate HO‐1 expression in HGFs by root canal sealers, HGFs were pretreated with glutathione (GSH) synthesis precursor 2‐oxothiazolidine‐4‐carboxylic acid (OTZ) and GSH synthesis inhibitor buthionine sulfoximine (BSO) for 24 h. The pretreatment with OTZ decreased the N2‐induced HO‐1 protein level by ∼32% (p < 0.05). However, BSO enhanced the N2‐induced HO‐1 protein level by up to twofold (p < 0.05). Similar results were found by Topseal. The pretreatment with OTZ decreased the Topseal‐induced HO‐1 protein level by ∼12% (p < 0.05). However, BSO enhanced the Topseal‐induced HO‐1 protein level by up to 1.7‐fold (p < 0.05). Taken together, HO‐1 expression might be one signal transduction pathway linked to the induction of stress‐inducible protein by root canal sealers. In addition, the activation of HO‐1 is augmented by oxidative stress. Factors that induce GSH synthesis may appear useful in preventing oxidative damage mediated by root canal sealers. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
Enhanced in‐vitro blood compatibility of 316L stainless steel surfaces by reactive landing of hyaluronan ions
Authors: Volný Michael , Elam W. Timothy , Ratner Buddy D. , Turec̆ek František
Published: July 2006

A novel dry process for immobilization of hyaluronan on stainless steel surfaces is presented. This process that we call reactive landing is based on an interaction of hyperthermal gas‐phase hyaluronan ions with plasma‐cleaned and activated stainless steel surfaces. Reactive landing is performed on a unique instrument that combines an in‐situ plasma reactor with an electrospray ion source and ion transfer optics. Gas‐phase hyaluronan anions are obtained by electrospray ionization of sodium hyaluronan solutions and immobilized by reactive landing on large‐area stainless steel surfaces. The immobilized hyaluronan withstands extensive washing with polar solvents and solutions, and the washed surfaces maintain the protective properties against blood platelet activation. The mechanism of hyaluronan discharge and immobilization is discussed. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
Evaluation of machining methods for trabecular metal implants in a rabbit intramedullary osseointegration model
Authors: Deglurkar Mukund , Davy Dwight T. , Stewart Matthew , Goldberg Victor M. , Welter Jean F.
Published: July 2006

Implant success is dependent in part on the interaction of the implant with the surrounding tissues. Porous tantalum implants (Trabecular Metal™, TM) have been shown to have excellent osseointegration. Machining this material to complex shapes with close tolerances is difficult because of its open structure and the ductile nature of metallic tantalum. Conventional machining results in occlusion of most of the surface porosity by the smearing of soft metal. This study compared TM samples finished by three processing techniques: conventional machining, electrical discharge machining, and nonmachined, “as‐prepared.” The TM samples were studied in a rabbit distal femoral intramedullary osseointegration model and in cell culture. We assessed the effects of these machining methods at 4, 8, and 12 weeks after implant placement. The finishing technique had a profound effect on the physical presentation of the implant interface: conventional machining reduced surface porosity to 30% compared to bulk porosities in the 70% range. Bone ongrowth was similar in all groups, while bone ingrowth was significantly greater in the nonmachined samples. The resulting mechanical properties of the bone implant‐interface were similar in all three groups, with only interface stiffness and interface shear modulus being significantly higher in the machined samples. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
Molecular dynamics simulations of liquid methanol and methanol–water mixtures with polarizable models
Authors: Yu Haibo , Geerke Daan P. , Liu Haiyan , van Gunsteren Wilfred F.
Published: July 2006

A polarizable model for simulation of liquid methanol, compatible with the COS/G2 water model, has been developed using the Charge‐on‐Spring (COS) technique. The model consists of three point charges, with one polarizable center on the oxygen atom. The Lennard–Jones parameters on the oxygen atom together with the molecular polarizability were varied to reproduce the experimental heat of vaporization and density of liquid methanol at ambient conditions. We examined the energies of various methanol dimers in the gas phase and compared them with values obtained from ab initio calculations. The model was then used to study the thermodynamic, dynamic, structural, and dielectric properties of liquid methanol as well as of a methanol–water mixture. A microscopic picture of the structure of pure liquid methanol and of the methanol–water mixture is provided. Good agreement was found between the results from our model simulations and available experimental and ab initio calculation data. In particular, the experimental dielectric permittivity of 32 could be reproduced, which had been shown to be difficult when using nonpolarizable models. © 2006 Wiley Periodicals, Inc. J Comput Chem 27: 1494–1504, 2006
Optimisation by response surface methodology of fungal lipase production on olive mill wastewater
Authors: D'Annibale Alessandro , Brozzoli Viviana , Crognale Silvia , Gallo Anna Maria , Federici Federico , Petruccioli Maurizio
Published: July 2006

The suitability of olive mill wastewater (OMW) as a growth medium for lipase production was assessed using Penicillium citrinum NRRL 1841, a versatile strain capable of producing lipase on several OMW typologies differing widely in their chemical oxygen demand, polyphenol and total sugar contents. Lipase production by P. citrinum in OMW‐based media was significantly stimulated by nitrogen addition, with ammonium chloride proving to be the most effective source. In contrast, the addition of vegetable oils did not significantly affect lipase production. On the basis of these results, lipase production was subsequently optimised in shaken flasks by a central composite design. To this aim, the impact of three crucial variables, namely initial pH and concentrations of ammonium chloride and yeast extract, was investigated. Maximum lipase activity (ca 1230 U dm−3) was reached after 188 h of fermentation. The process was subsequently assessed in stirred tank and bubble column reactors of identical working capacity (3 dm3), leading to lower lipase production (735 and 430 U dm−3 respectively) than in shaken flasks. Copyright © 2006 Society of Chemical Industry
Response of methanogen populations to organic load increase during anaerobic digestion of olive mill wastewater
Authors: Rizzi Aurora , Zucchi Mauro , Borin Sara , Marzorati Massimo , Sorlini Claudia , Daffonchio Daniele
Published: July 2006

Process performances of an upflow anaerobic filter treating olive mill wastewater and the response of methanogenic Archaea to increasing volumetric organic load (VOL) were studied. At a VOL of 15 g chemical oxygen demand (COD) L−1 day−1, 90% of the influent COD was removed. Following a VOL increase from 6 to 15 g COD L−1 day−1, the polymerase chain reaction (PCR) titre of hydrogenotrophic Methanobacterium, determined by magnetic capture of the target DNA and group‐specific PCR based on the 16S rRNA gene, decreased from 1011 to 108 cells g−1 sludge, while that of Methanomicrobiaceae and relatives increased from 104 to 106 cells g−1 sludge. Methanosaeta‐like acetoclastic methanogens were less affected by VOL variation and dominated at high VOL with a 16S rRNA gene PCR titre of 109 cells g−1 sludge. Single‐strand conformation polymorphism analysis of the PCR‐amplified archaeal 16S rRNA gene showed a stable band pattern, indicating that VOL variation affected the methanogen PCR titre but not the archaeal community structure. Copyright © 2006 Society of Chemical Industry
Thermostable carbohydrate‐binding modules in affinity chromatography
Authors: Johansson Reine , Gunnarsson Lavinia Cicortas , Ohlin Mats , Ohlson Sten
Published: July 2006

Affinity chromatography is routinely used mostly on a preparative scale to isolate different biomolecules such as proteins and carbohydrates. To this end a variety of proteins is in common use as ligands. To extend the arsenal of binders intended for separation of carbohydrates, we have explored the use of carbohydrate‐binding modules (CBM) in affinity chromatography. The thermostable protein CBM4‐2 and two variants (X‐6 and A‐6) thereof, selected from a newly constructed combinatorial library, were chosen for this study. The CBM4‐2 predominantly binds to xylans but also crossreacts with glucose‐based oligomers. The two CBM‐variants X‐6 and A‐6 had been selected for binding to xylan and Avicel® (a mixture of amorphous and microcrystalline cellulose), respectively. To assess the ability of these proteins to separate carbohydrates, they were immobilized to macroporous microparticulate silica and analyses were conducted at temperatures ranging from 25 to 65°C.

With the given set of CBM‐variants, we were able to separate cello‐ and xylo‐oligomers under isocratic conditions. The affinities of the CBMs for their targets were weak (in the mM–µM range) and by adjusting the column temperature we could optimize peak resolution and chromatographic retention times. The access to thermostable CBM‐variants with diverse affinities and selectivities holds promise to be an efficient tool in the field of affinity chromatography for the separation of carbohydrates. Copyright © 2006 John Wiley & Sons, Ltd.