bluuebunny/crossref_metadata_2025 huggingface dataset:
Connective Tissue Growth Factor Mediates High Glucose Effects on Matrix Degradation through Tissue Inhibitor of Matrix Metalloproteinase Type 1: Implications for Diabetic Nephropathy
Authors: McLennan S. V. , Wang X. Y. , Moreno V. , Yue D. K. , Twigg S. M.
Published: September 2004

High glucose concentration inhibits matrix degradation and affects the activities of the enzymes responsible, the matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs). Connective tissue growth factor (CTGF) expression is increased in diabetic nephropathy and is a downstream mediator of TGF-β actions. However, whether CTGF regulates matrix degradation and the mechanism of effect in diabetes has not been reported. Human mesangial cells were cultured in media containing 5 or 25 mm glucose and, in some experiments, with recombinant human (rh)CTGF (0–1000 ng/ml) and/or appropriate neutralizing antibodies. Matrix degradation was inhibited by rhCTGF in a dose-dependent manner, and the decrease in matrix degradation caused by high glucose and by TGF-β was significantly attenuated by addition of CTGF-neutralizing antibody (by 40.2 and 69.1%, respectively). Similar to 25 mm glucose, addition of rhCTGF increased MMP-2, TIMP-1, and TIMP-3 mRNA by 2.5-, 2.1-, and 1.6-fold, respectively (P < 0.05) but had no effect on membrane-type (MT)1-MMP or TIMP-2. Addition of TIMP-1 antibody to conditioned medium abolished the decrease in degradation caused by rhCTGF and partially prevented (by 79%) the glucose-induced inhibition of matrix degradation. In vivo studies of glomeruli from diabetic and control rats showed that intensive insulin treatment prevented the increase in expression of CTGF and TIMP-1 and attenuated the decreased matrix degradation seen in diabetes. In summary, CTGF inhibits matrix degradation by increasing TIMP-1 expression, and by this action it contributes to the inhibition of matrix breakdown by high glucose, implying that CTGF has a role in the reduced matrix degradation observed in diabetic nephropathy.
Ataxia-Telangiectasia Mutated Gene Controls Insulin-Like Growth Factor I Receptor Gene Expression in a Deoxyribonucleic Acid Damage Response Pathway via Mechanisms Involving Zinc-Finger Transcription Factors Sp1 and WT1
Authors: Shahrabani-Gargir Limor , Pandita Tej K. , Werner Haim
Published: September 2004

The IGF-I receptor (IGF-IR) has a central role in cell cycle progression as well as in the establishment of the transformed phenotype. Increased expression of the IGF-IR gene, in addition, is correlated with acquisition of radioresistance for cell killing. The ataxia-telangiectasia mutated (ATM) gene product has a pivotal role in coordinating the cellular response to DNA damage. The present study was aimed at testing the hypothesis that the ability of ATM to coordinate the DNA damage response that will lead to cell survival or, alternatively, to apoptosis depends, to a significant extent, on its capacity to control IGF-IR gene expression. The potential involvement of ATM in regulation of IGF-IR expression and function was investigated in isogenic cells with and without ATM function [AT22IJE-T/pEBS7 (ATM −/−) and ATM-corrected AT22IJE-T/YZ5 (ATM +/+) cells and 293 human embryonic kidney cells transfected with small interfering RNAs targeted to ATM]. In addition, the effect of ATM on IGF-IR expression was assessed in nonisogenic cells with ATM function (HFF + human telomerase reverse transcriptase) and without ATM function (GM5823 + human telomerase reverse transcriptase). Results obtained showed that IGF-IR gene expression and IGF-IR promoter activity were largely reduced in ATM −/− cells. Addition of the radiomimetic agent neocarzinostatin for 4 h, however, induced a significant increase in IGF-IR levels in cells without ATM function. In addition, IGF-I-induced IGF-IR and insulin receptor substrate-1 phosphorylation were greatly impaired in ATM-deficient cells. Furthermore, we identified zinc-finger transcription factors Sp1 and WT1 as potential mediators of the effect of ATM on IGF-IR gene expression. The present data suggests that the IGF-IR gene is a novel downstream target in an ATM-mediated DNA damage response pathway. Deregulated expression of the IGF-IR gene after ionizing radiation may be linked to genomic instability and enhanced transforming capacity.
Developmental Expression of Estrogen Receptor (ER) α and ERβ in the Hamster Ovary: Regulation by Follicle-Stimulating Hormone
Authors: Yang Peixin , Wang Jinrong , Shen Yulei , Roy Shyamal K.
Published: September 2004

Perinatal expression of estrogen receptor (ER) protein and mRNA and the influence of FSH on this process were examined by immunofluorescence and RT-PCR using ovaries from fetal (d 13–15 of gestation) and postnatal [postnatal d 1–15 (P1–P15)] hamsters and from 8-d-old hamsters exposed in utero to an anti-FSH serum on d 12 of gestation and saline or equine chorionic gonadotropin (eCG) on P1. A few somatic cells expressing ERα immunoreactivity appeared first on d 14 of gestation and increased markedly by P8–P15 in the interstitial cells and granulosa cells of primordial follicles. In contrast, appreciable ERβ immunoreactivity was localized on d 13 of gestation, and more cells expressed ERβ immunoreactivity by P1–P8. By P7, ERβ immunoreactivity was present in cells adjacent to the oocytes, and by P8, ERβ was preferentially localized in the granulosa cells. Receptor immunoreactivities decreased markedly in P8 ovaries exposed in utero to the FSH antiserum but were reversed with postnatal eCG replacement. Oocytes and somatic cells expressed ERα and ERβ mRNA, and levels of ER mRNA in the ovary increased by P7–P8, corresponding to the appearance of primordial follicles. Thereafter, only ERβ mRNA levels increased progressively with postnatal ovary development. Similar to ER protein, mRNA levels decreased significantly in FSH antiserum-treated ovaries but were restored by eCG. These results indicate that both ER subtypes are expressed in undifferentiated somatic cells and the oocytes during perinatal ovary development in the hamster; however, ERβ expression segregates with the differentiation of granulosa cells. Furthermore, ER expression and differentiation of somatic cells to granulosa cells depend on perinatal FSH action.
Postnatal Regression of Hypothalamic Dopaminergic Neurons in Prolactin-Deficient Snell Dwarf Mice
Authors: Phelps C. J.
Published: September 2004

Both Snell (Pit-1dw or dwj, dw/dw) and Ames (Prophet of Pit-1df, df/df) dwarf mice fail to produce prolactin (PRL) as well as GH due to deficient transcription factor Pit-1 activity and have reduced numbers of hypothalamic PRL-inhibiting area A12 tuberoinfundibular dopaminergic (TIDA) neurons. It has been reported that the TIDA deficit in Ames dwarf mice develops postnatally as a reduction in number after an initial increase that is comparable to that of normal siblings. The present study was designed to characterize A12 TIDA neuronal development in the Snell dwarf (dw/dw) compared with littermate normal mice. Brains of normal (DW/?) and dwj/dwj mice were examined at 7, 14, 21, 30, and ≥ 60 postnatal days (d) by catecholamine fluorescence and quantification of neuron number after tyrosine hydroxylase immunostaining in dopaminergic (DA) areas A12, A13 (medial zona incerta), and A14 (periventricular nucleus). Fluorescence was less in dw/dw than in DW/? A12 perikarya and median eminence but was not reduced in other DA areas, such as substantia nigra, at all ages; A12 fluorescence was virtually absent in Snell dwarf adults. Numbers of TIDA neurons were comparable in normal and Snell dwarf mice at 7 d. In normal (DW/?) mice, A12 neurons increased in number to adult levels at 14 d and were significantly higher than in Snell dwarf (dw/dw) mice at 14 d (P < 0.05) and at subsequent ages (P < 0.01). In Snell dwarf mice, numbers of A12 neurons did not differ at 7, 14, and 21 d, decreased at 30 d (P < 0.05), and reached, at 60 d, 23% of the population in normal sibling mice (P < 0.01 compared with earlier ages). Neuron numbers in nonhypophysiotropic DA area A13 did not vary with age or phenotype. In A14, cell number was higher in both phenotypes at 14 d (P < 0.05 for DW/?; P < 0.01 for dw/dw); neuron number was lower in dw/dw than in DW/? mice at 30 d (P < 0.05) and 60 d (P < 0.01). Thus, compared with normal mice of the same strain, the A12 deficit is more severe in Snell (dw/dw) than in Ames (df/df) dwarf hypothalamus (48% of DF/?), as previously reported, and develops as a decline from the population present at 7 d rather than first increasing. A reduction in A14 neuron number also occurs in the Snell dwarf. Treatment of DW/dw- and dw/dw-containing litters with ovine PRL (50 μg/d, ip), beginning at 12 or 7 d and continuing until 42 d, resulted in TIDA neuron numbers in Snell dwarfs that were lower than those in normal siblings (P < 0.01 for both) but were higher than in untreated adult dwarfs and comparable to the TIDA population size in dwarfs at 7 d, indicating that PRL maintained this maximal number and prevented TIDA neuron dedifferentiation, which occurs in dwarf postnatal development.
Transcriptional Regulation of Agouti-Related Protein (Agrp) in Transgenic Mice
Authors: Kaelin Christopher B. , Xu Allison Wanting , Lu Xin-Yun , Barsh Gregory S.
Published: September 2004

Agouti-related protein (Agrp) encodes a hypothalamic neuropeptide that promotes positive energy balance by stimulating food intake and reducing energy expenditure. Agrp expression in the brain is restricted to neurons within the arcuate nucleus of the hypothalamus, and expression levels are elevated as a consequence of food deprivation. We tested a series of bacterial artificial chromosome reporter constructs with varying amounts of sequence flanking the Agrp transcription unit in transgenic mice to identify and refine a region of DNA capable of recapitulating characteristics of Agrp expression. We report that a 42.5-kb region upstream of Agrp, containing three distinct regions that are evolutionarily conserved between mouse and human, is necessary and sufficient to consistently drive reporter expression specifically within AgRP neurons in a fasting-responsive manner. In addition, we demonstrate that this region allows for the stable expression of Cre recombinase in transgenic mice, providing a genetic tool for studying anabolic neural circuits that control energy balance.
Attitudes and Intentions of Future Health Care Providers Toward Abortion Provision
Authors: Shotorbani Solmaz , Zimmerman Frederick J. , Bell Janice F. , Ward Deborah , Assefi Nassim
Published: September 2004

CONTEXT: Induced abortion is one of the most common procedures performed among women in the United States. However, 87% of all counties had no abortion provider in 2000, and little is known about the attitudes and intentions of future health care providers, including advanced clinical practitioners, regarding abortion provision.

METHODS: During March 2002, first‐ and second‐year students in health sciences programs (i.e., medicine, physician assistant and nursing) at the University of Washington were anonymously surveyed. Univariate, bivariate and multi‐variate analyses were used to determine students' attitudes and intentions regarding provision of abortion services.

RESULTS: Of the 312 students who completed the survey, 70% supported the availability of legal abortion under any circumstances. Thirty‐one percent intended to provide medical abortion in their practice, and 18% planned to offer surgical abortion. Fifty‐two percent of all respondents agreed that advanced clinical practitioners should be able to provide medical abortion, and 37% agreed that they should be able to provide surgical abortion services; however, greater proportions of advanced clinical practitioners (45–83%) than of medical students (21–43%) expressed such support. Sixty‐four percent of all respondents were willing to attend a program whose curriculum requires abortion training.

CONCLUSIONS: Although it may not be possible to require abortion training for every future health care provider, making abortion a standard part of clinical training would provide opportunities for future physicians and advanced clinical practitioners, and would likely ameliorate the abortion provider shortage.
Acceptability of the Vaginal Diaphragm Among Current Users
Authors: Maher Julie E. , Harvey S. Marie , Bird Sheryl Thorburn , Stevens Victor J. , Beckman Linda J.
Published: September 2004

CONTEXT: Interest in the diaphragm has been growing, in part because it is a female‐controlled method that might protect against HIV and other sexually transmitted diseases (STDs). A better understanding of diaphragm acceptability is needed.

METHODS: In 2001–2002, female members of a managed care organization were interviewed by telephone. The 215 participants, aged 19–49, who reported diaphragm use during the past three months were asked about their experience with the method and background characteristics. Characteristics associated with women's satisfaction with and consistent use of the diaphragm were identified through multiple logistic regression analysis.

RESULTS: Most participants had a low risk for HIV and other STDs. The mean duration of diaphragm use was 8.5 years. Although only 42% of participants reported consistent use in the past three months, most were satisfied with the method (79%) and planned to use it at next vaginal intercourse (85%). Satisfied users had significantly higher diaphragm use self‐efficacy and more positive perceptions of the method than those not satisfied. Consistent use was significantly associated with older age and having had some college education rather than none. More than half of women cited dissatisfaction with previous methods (72%) and provider recommendation (61%) as moderately to extremely important in their decision to begin diaphragm use. When asked what they would change about the diaphragm, 32% mentioned concerns related to inserting or removing it.

CONCLUSIONS: From an acceptability point of view, the diaphragm appears to be a viable candidate for a female‐controlled method for prevention of HIV and other STDs. Our findings have important implications for the reintroduc‐tion of the traditional diaphragm and development of new diaphragm‐like products.
A Comparison of Hispanic and White Adolescent Females' Use of Family Planning Services in California
Authors: Solorio M. Rosa , Yu Hongjian , Brown E. Richard , Becerra Lida , Gelberg Lillian
Published: September 2004

CONTEXT: In California, the adolescent birthrate among Hispanics is three times that among whites. Because Hispanics are projected to make up one‐half of the state's adolescents by 2020, it is important to determine how cultural and health policy‐relevant factors are linked to this group's use of family planning services.

METHODS: Data from the 2001 California Health Interview Survey were used to examine characteristics of Hispanic and white females aged 14–17, including patterns of use of family planning services in the past year. Multivariate logistic regression analyses were conducted to assess the association between selected characteristics and use of family planning services.

RESULTS: Compared with white adolescents, Hispanic adolescents came from poorer families, had a poorer health status, less commonly had a regular source of primary health care and had lower rates of alcohol and drug use, and of sexual experience. Although the proportion of sexually experienced Hispanics who had used family planning services was similar to that of whites (34% and 27%, respectively), the proportion who had ever been pregnant and used such services was significantly larger (42% vs. 9%). In the multivariate analysis, Hispanic adolescents who had ever been pregnant were significantly more likely than whites who had not to have used family planning services in the past year (odds ratio, 11.6).

CONCLUSIONS: A need exists for family planning programs to target Hispanic adolescents before they become pregnant, and to send a clear message that contraceptive services are available and should be used before a woman ever has a pregnancy.
A Randomized Study of a Pregnancy and Disease Prevention Intervention for Hispanic Couples
Authors: Harvey S. Marie , Henderson Jillian T. , Thorburn Sheryl , Beckman Linda J. , Casillas America , Mendez Leo , Cervantes Roxana
Published: September 2004

CONTEXT: Many Hispanic women are at elevated risk for HIV infection because of the sexual behavior of their male partner. Yet, couple‐based risk‐reduction interventions for this population have not been developed and scientifically evaluated.

METHODS: A sample of 146 Hispanic couples who received either a risk reduction intervention or the community educational standard of care were followed up at three months (men and women) and six months (women only) to measure the consistency of both condom use and effective contraceptive use, and the frequency of unprotected vaginal sex. Analyses were conducted to identify differences between the two groups at baseline and follow‐up interviews, and changes over time.

RESULTS: At follow‐up, the two groups did not differ on any risk‐related outcomes; over time, both groups increased the reported consistency of condom use and of use of effective contraceptive methods, and reduced their frequency of unprotected sex.

CONCLUSIONS: If further research confirms that simply bringing couples together for a single‐session, culturally appropriate risk reduction intervention helps them adopt protective behaviors, more intensive (and costly) interventions may not be necessary.
Detection of Antinuclear Antibodies by Solid-Phase Immunoassays and Immunofluorescence Analysis
Authors: Fenger Mogens , Wiik Allan , Høier-Madsen Mimi , Lykkegaard Jens J , Rozenfeld Teresa , Hansen Michael S , Samsoe Bente Danneskjold , Jacobsen Søren
Published: September 2004

Background: Antinuclear antibodies (ANAs) are associated with several inflammatory rheumatic diseases. The aim of the present work was to evaluate enzyme immunoassays (EIAs) and compare them with classic immunofluorescent analysis (IFA) for the detection of ANA.

Methods: Seven enzyme immunoassays were used in this study. All assays were applied as described by the manufacturers. Three populations were included in the study: (a) a population of patients with well-established autoimmune inflammatory disease (n = 102); (b) a population in which a rheumatic disease was diagnosed up to 5 years after an IFA was performed (n = 164); and (c) a population of consecutive outpatients suspected to have a rheumatic disease (n = 101). The current clinical diagnoses of the patients served as the standard against which performance of the assays was evaluated.

Results: In patients with well-established rheumatic disorders, the newly developed EIA in which HEp-2 extracts were included had sensitivities and specificities comparable to or in some instances better than the IFA. The assays without HEp-2 extracts included had significantly lower sensitivities and specificities. In the outpatient population, up to 51% of patients had positive ANA tests that did not correspond to classic ANA-associated disease. However, in the assays in which the HEp-2 extracts were not included, the false-positive rate was <10%. The false-negative rate judged against IFA differed from assay to assay and disease to disease and was mostly <10%.

Conclusions: In this study, the sensitivities of EIAs and IFA were largely comparable. However, EIAs without HEp-2 extracts included had a low sensitivity but a high specificity, particularly in nonselected populations. The choice of test is highly dependent on the clinical setting in which the ANA test is to be used and on laboratory policy.
Effect of Injection Parameters on Velocity and Temperature Distributions of Alumina‐Titania In‐Flight Particles in Atmospheric Plasma Spraying
Authors: Guessasma S. , Montavon G. , Coddet C.
Published: August 2004

Three injection parameters (carrier gas flow rate, injector diameter and injection distance) were correlated to the characteristic distributions in the case of alumina titania in‐flight particles. A high speed two color pyrometer was implemented to measure, at the centre of the particle flow, individual in‐flight particle characteristics, which were used to build velocity and temperature distributions. Results showed that mean characteristic variations were explained by distribution width flattening and centre shift. These were not significant compared to energetic parameter effects.
Cutting Temperatures and Their Effects on the Machining Behaviour in Drilling Reinforced Plastic Composites
Authors: Weinert K. , Kempmann C.
Published: August 2004

Construction parts consisting of modern composite materials made of fiber reinforced polymers still need to be machined, whereby special attention has to be paid to the machining quality. The machining quality implies dimensional accuracy as well as a defect‐free peripheral zone. Machining defects often occur as a consequence of excessive mechanical loads, which are often caused by wrong process conditions. Besides mechanical loads, the thermal influence on the composite material, which is induced by the cutting process itself, has to be considered as crucial. According to the thermo physical material properties of fiber reinforced polymers the boundary conditions differ from the machining of metals. Especially in drilling operations the heat removal is difficult, when dry machining is employed. Here, temperature measurements in drilling polymer composites are introduced and moreover the machining defects, which occurs according to the process temperatures, are presented.
Continuum Models for the Thermomechanical Behavior of Discontinuously Reinforced Materials
Authors: Böhm H.J.
Published: August 2004

Continuum micromechanical models have become important tools for understanding the thermomechanical behavior of composite materials. This work presents the most important continuum‐level approaches for modeling the thermomechanical behavior of discontinuously reinforced composites. Analytical and numerical models are covered, special emphasis being put on multi‐inclusion unit cell methods. The fields of application of the different models are discussed and selected applications are demonstrated.
Electroforming of Metallic Microparts on Sacrificial Molds made by Two‐component Injection Molding
Authors: Holstein N. , Piotter V. , Lorenz J. , Oskotski E. , Ruprecht R. , Schanz G. , Hausselt J.
Published: August 2004

One of the process developments required in Micro System Technology (MST) is oriented to the mass production of metallic microsystem components with high aspect ratios and high surface qualities by galvanic replication. The limiting factor is the generation of suitable templates for electroforming. A production of metallic microsystems or components in large numbers requires on one side the transcription of the special technique of the electroforming step in the LIGA process and on the other side replication and fast multiplication into a mass production process. The envisaged possibility will be given by thermoplastic injection molding of sacrificial molds and the following electroforming on these polymer molds.
In Situ Nondestructive Evaluation of the Accumulative Damage in Continuous Ceramic Fiber‐Ceramic Matrix Composites (CFCCs) using Submillimeter Range Electromagnetic Wave
Authors: Guo S. , Mamiya T. , Kagawa Y.
Published: August 2004

Monolithic ceramic materials usually show catastrophic failure behavior and this property limits application as structural components because the failure occurs easily from a small flaw that usually exists in the materials. To overcome this, incorporation of a fine ceramic fiber into a brittle ceramic has been examined and the obtained material is named as continuous fiber‐ceramic matrix composites (CFCCs).
Microwave Detection of Defects and Inhomogeneities in Low Pressure Injection Moulded β‐TCP Ceramic
Authors: Martins S.T. , Dannheim H. , Hädrich H. , Weinzierl J. , Müller F.A. , Greil P.
Published: August 2004

The feasibility of a nondestructive microwave inspection to detect internal processing defects in low pressure injection moulded ceramic parts was investigated. A β‐TCP (β‐tricalcium phosphate, Ca3(PO4)2) slurry with paraffin, ethylene vinyl acetate copolymer and stearic acid as binder system was injection moulded with a pressure of 0.2 MPa and subsequently inspected in a 94.1 GHz microwave testing device. The transmitting amplitude and phase displacement images were compared with visual inspection of the samples. The novel method was able to detect, localize and geometrically characterize inhomogeneities and non‐visible defects present in green ceramic compacts.
Tailored Microstructures: Can a Dream come True?
Authors: Gottstein G.
Published: August 2004

The mechanical properties of crystalline solids are determined by the spatial distribution of chemical elements and crystal defects, which is referred to as microstructure. Microstructure changes during processing, and its evolution can be influenced by processing conditions and external fields. Advanced microstructure codes can cover the through‐process microstructural evolution and allow first predictions of terminal materials properties.
Improved Green Strength of Ceramics Through Aqueous Gelcasting
Authors: Santacruz I. , Baudín C. , Moreno R. , Nieto M.I.
Published: August 2004

Aqueous gelcasting of alumina is optimised by preparing concentrated agarose solutions under overpressure conditions. The better dissolution reduces the viscosity and improves the microstructural control leading to green densities higher than 60 % of TD. The enhancement of the green strength is not accompanied by a significant increase of the plastic behaviour during fracture for agarose contents < 1 wt.%. Sintered densities > 99 % of theoretical are obtained.
Superalloy IN625 with Cellular Microstructure – Fabrication Route and Mechanical Properties
Authors: Quadbeck P. , Kaschta J. , Singer R.F.
Published: August 2004

Cellular microstructures are of special interest for applications in filtering, heat transfer or acoustic absorption. In the present paper a new route for the preparation of such structures from superalloys will be presented. Polyoxymethylene (POM) is used as space holder which can be injection molded into any desired shape. Densification of the cell walls and struts is achieved by supersolidus liquid phase sintering (SLPS).
Technical Cost Modeling for the Mechanical Milling at Cryogenic Temperature (Cryomilling)
Authors: Ye J. , Schoenung J.M.
Published: August 2004

Cryomilling is one of the few technologies available to fabricate a large quantity of nanostructured materials. No matter how exciting and promising a technology is, its ultimate realization is invariably dependent on economic success. Technical cost modeling was employed in this paper to analyze the processing cost of cryomilling. The results demonstrated that cryomilling has the potential to be commercially economical to fabricate nanostructured materials.
Comparison of Single Crystal Simple Shear Deformation Experiments with Crystal Plasticity Finite Element Simulations
Authors: Roters F. , Wang Y. , Kuo J.‐C. , Raabe D.
Published: August 2004

The crystal plasticity finite element method is an ideal approach to simulate the mechanics, texture, and elastic‐plastic anisotropy of materials. Experimental validation of such simulations requires to measure these quantities without the disturbing influence of friction known for instance from channel‐die experiments. This work presents results obtained form simple shear deformation experiments of aluminium single crystals together with corresponding crystal plasticity finite element simulations.
Evolution of the Mechanical Properties of Aluminum Containing Al8Fe2Si Precipitates During Equal Channel Angular Pressing
Authors: Korchef A. , Njah N. , Masmoudi J. , Kolsi A. , Champion Y. , Guérin S. , Leroux C.
Published: August 2004

Mechanical behaviour of submicrometer grain sized aluminium (99.1%), containing a low volume fraction of Al8Fe2Si precipitates, processed by Equal Channel Angular (ECA) pressing was investigated using Vickers microhardness, compression and tensile tests. In compression, samples machined along three orthogonal directions exhibited different yield strengths and cylindrical samples became elliptic after pressing. Tensile results showed an increase of the yield strength without loss of ductility. After ECA pressing for one pass, annealing at 200°C leads to a significant strengthening. A dependence of the ductility with strain rate was also observed.
Cross Linking Behavior of Preceramic Polymers Effected by UV‐ and Synchrotron Radiation
Authors: Schulz M. , Börner M. , Göttert J. , Hanemann T. , Haußelt J. , Motz G.
Published: August 2004

Ceramic properties are important for applications in micro system technologies. Various lithographic methods are being widely used for the direct fabrication of very precise plastic or metal micro structured surfaces. High temperature stable ceramics can be achieved from preceramic polymers using relatively low pyrolysis temperatures. A direct lithographic process to produce ceramic microstructures has been developed.
Deformation and Failure Modeling of Fiber Reinforced Ceramics with Porous Matrix
Authors: Tushtev K. , Horvath J. , Koch D. , Grathwohl G.
Published: August 2004

A 2D reinforced carbon/carbon‐composite was investigated in tensile tests with variable fiber orientation relative to the loading direction. The experimental results from two different orientations (0° and 45°) are used to derive material parameters which are implemented into a macroscopic model. The model describes the materials response, i.e. the stress‐strain behavior and the ultimate failure of the composite, under any angle between fiber orientation and loading direction. The predicted data are confirmed by experimental results.
Familial insertion (3;5)(q25.3;q22.1q31.3) with deletion or duplication of chromosome region 5q22.1‐5q31.3 in ten unbalanced carriers
Authors: Arens Y.H.J.M. , Engelen J.J.M. , Govaerts L.C.P. , van Ravenswaay C.M. , Loneus W.H. , van Lent‐Albrechts J.C.M. , van der Blij‐Philipsen M. , Hamers A.J.H. , Schrander‐Stumpel C.T.R.M.
Published: August 2004

We report on the clinical and cytogenetic data of a large family with an unbalanced insertion translocation (3;5)(q25.3;q22.1q31.3). Analysis of GTG‐banded chromosomes demonstrated that unbalanced inheritance of a parental insertion translocation caused either a partial deletion or duplication 5q in this family. The derivative chromosomes were characterized further using microdissection and FISH with band‐specific probes. The clinical picture of the proband with a partial deletion of chromosome 5 was characterized by moderate psychomotor retardation, mild facial dysmorphism, cleft palate, and single transverse crease. The family members with a partial duplication of chromosome 5 were borderline intelligent, had mild facial dysmorphism, a cardiac anomaly, and a high‐pitched voice. The unbalanced carriers were compared with patients reported in the literature with a duplication or deletion of chromosome region 5q22.1 → 5q31.3. © 2004 Wiley‐Liss, Inc.
A mixed epigenetic/genetic model for oligogenic inheritance of autism with a limited role for UBE3A
Authors: Jiang Yong‐hui , Sahoo Trilochan , Michaelis Ron C. , Bercovich Dani , Bressler Jan , Kashork Catherine D. , Liu Qian , Shaffer Lisa G. , Schroer Richard J. , Stockton David W. , Spielman Richard S. , Stevenson Roger E. , Beaudet Arthur L.
Published: August 2004

The genetic contribution to autism is often attributed to the combined effects of many loci (ten or more). This conclusion is based in part on the much lower concordance for dizygotic (DZ) than for monozygotic (MZ) twins, and is consistent with the failure to find strong evidence for linkage in genome‐wide studies. We propose that the twin data are compatible with oligogenic inheritance combined with a major, genetic or epigenetic, de novo component to the etiology. Based on evidence that maternal but not paternal duplications of chromosome 15q cause autism, we attempted to test the hypothesis that autism involves oligogenic inheritance (two or more loci) and that the Angelman gene (UBE3A), which encodes the E6‐AP ubiquitin ligase, is one of the contributing genes. A search for epigenetic abnormalities led to the discovery of a tissue‐specific differentially methylated region (DMR) downstream of the UBE3A coding exons, but the region was not abnormal in autism lymphoblasts or brain samples. Based on evidence for allele sharing in 15q among sib‐pairs, abnormal DNA methylation at the 5′‐CpG island of UBE3A in one of 17 autism brains, and decreased E6‐AP protein in some autism brains, we propose a mixed epigenetic and genetic model for autism with both de novo and inherited contributions. The role of UBE3A may be quantitatively modest, but interacting proteins such as those ubiquitinated by UBE3A may be candidates for a larger role in an oligogenic model. A mixed epigenetic and genetic and mixed de novo and inherited (MEGDI) model could be relevant to other “complex disease traits”. © 2004 Wiley‐Liss, Inc.
Mutation analysis of the tumor suppressorPTENand the glypican 3 (GPC3) gene in patients diagnosed with Proteus syndrome
Authors: Thiffault I. , Schwartz C.E. , Der Kaloustian V. , Foulkes W.D.
Published: August 2004

Proteus syndrome is a complex hamartomatous disorder characterized by asymmetrical gigantism, epidermal nevi, vascular malformations, hamartomas, lipomas, and hyperostosis. Since the syndrome was first described, many hypotheses have been proposed to explain its occurrence. The most plausible is Happle's somatic mosaic hypothesis, but no somatic mutations in candidate genes have been reported to be clearly involved in Proteus syndrome. However, germ‐linePTENmutations have been reported in patients with Proteus and in “Proteus‐like disorders.” Other studies of patients with Proteus syndrome have not supported these findings. In this study, affected and unaffected tissue from six patients diagnosed with Proteus syndrome were screened by direct sequencing of genomic DNA to determine if there might be an association between germ‐line or somatic mutations inPTENorGPC3and the development of Proteus syndrome. No intra‐exonic mutations were identified, indicating that neitherPTENnorGPC3are likely to have major roles in the etiology of Proteus syndrome in our series of patients. © 2004 Wiley‐Liss, Inc.
From Weakly Coordinating to Non‐Coordinating Anions? A Simple Preparation of the Silver Salt of the Least Coordinating Anion and Its Application To Determine the Ground State Structure of the Ag(η2‐P4)2+ Cation
Authors: Bihlmeier Angela , Gonsior Marcin , Raabe Ines , Trapp Nils , Krossing Ingo
Published: August 2004

The unexpected but facile preparation of the silver salt of the least coordinating [(RO)3Al‐F‐Al(OR)3]− anion (R=C(CF3)3) by reaction of Ag[Al(OR)4] with one equivalent of PCl3 is described. The mechanism of the formation of Ag[(RO)3Al‐F‐Al(OR)3] is explained based on the available experimental data as well as on quantum chemical calculations with the inclusion of entropy and COSMO solvation enthalpies. The crystal structures of (RO)3Al←OC4H8, Cs+[(RO)2(Me)Al‐F‐Al(Me)(OR)2]−, Ag(CH2Cl2)3+[(RO)3Al‐F‐Al(OR)3]− and Ag(η2‐P4)2+[(RO)3Al‐F‐Al(OR)3]− are described. From the collected data it will be shown that the [(RO)3Al‐F‐Al(OR)3]− anion is the least coordinating anion currently known. With respect to the fluoride ion affinity of two parent Lewis acids Al(OR)3 of 685 kJ mol−1, the ligand affinity (441 kJ mol−1), the proton and copper decomposition reactions (−983 and −297 kJ mol−1) as well as HOMO level and HOMO–LUMO gap and in comparison with [Sb4F21]−, [Sb(OTeF5)6]−, [Al(OR)4]− as well as [B(RF)4]− (RF=CF3 or C6F5) the [(RO)3Al‐F‐Al(OR)3]− anion is among the best weakly coordinating anions (WCAs) according to each value. In contrast to most of the other cited anions, the [(RO)3Al‐F‐Al(OR)3] anion is available by a simple preparation in conventional inorganic laboratories. The least coordinating character of this anion was employed to clarify the question of the ground state geometry of the Ag(η2‐P4)2+ cation (D2h, D2 or D2d?). In agreement with computational data and NMR spectra it could be shown that the rotation along the Ag‐(P‐P‐centroid) vector has no barrier and that the structure adopted in the solid state depends on packing effects which lead to an almost D2h symmetric Ag(η2‐P4)2+ cation (0 to 10.6° torsion) for the more symmetrical [Al(OR)4]− anion, but to a D2 symmetric Ag(η2‐P4)2+ cation with a 44° twist angle of the two AgP2 planes for the less symmetrical [(RO)3Al‐F‐Al(OR)3]− anion. This implies that silver back bonding, suggested by quantum chemical population analyses to be of importance, is only weak.
Controlling the Conformation of Arylamides: Computational Studies of Intramolecular Hydrogen Bonds between Amides and Ethers or Thioethers
Authors: Doerksen Robert J. , Chen Bin , Liu Dahui , Tew Gregory N. , DeGrado William F. , Klein Michael L.
Published: August 2004

The role of anortho‐alkylthioether group in controlling the conformation around the ringN bonds ofmeta‐connected arylamide oligomers is studied. Density functional theory (DFT) geometries of model compounds, including acetanilide, an ether acetanilide, and a thioether acetanilide, and their corresponding diamides, show that for either monoamide or diamide the alkyl side chain of the thioether should be perpendicular to the aryl plane, whereas for the ether monoamide, the alkyl side chain is in the aryl plane. DFT ringN torsional potentials and constrained geometries of the model compounds demonstrate that carbonylS repulsion leads to a high torsional barrier and that intramolecular NH⋅⋅⋅S and CH⋅⋅⋅O hydrogen bonds and ring–amide conjugation lead to NH having a preferred orientation in the benzene plane pointing towards S. The NH bond lengthens and theortho‐ring CH bond shortens in a regular pattern in the approach to the preferred orientation. Calculated IR frequencies for the NH stretch show a clear red shift between model compounds without and with the thioether side chain.
Zeolite Nanocrystals Inside Mesoporous TUD‐1: A High‐Performance Catalytic Composite
Authors: Waller Peter , Shan Zhiping , Marchese Leonardo , Tartaglione Guiseppina , Zhou Wuzong , Jansen Jacobus C. , Maschmeyer Thomas
Published: August 2004

A hierarchically structured composite material with interconnecting meso‐ and micropores has been developed with the aim to optimize zeolite performance. A general synthetic method has been developed that, in a controlled manner, allows for various types of nanosized zeolite to be incorporated into a three‐dimensional mesoporous matrix. Nanosized zeolite Beta was used to exemplify this new approach, resulting in a system in which zeolite Beta shows a higher cracking activity per gram of zeolite than pure nanosized zeolite Beta for the model feed n‐hexane. Additionally, FTIR studies of CO and NH3 adsorption revealed that the nature of the acid sites in the nanozeolite has been partially modified due to the interactions with the mesoporous matrix, TUD‐1.
A New Method for Simultaneous Estimation of Micellization Parameters from Conductometric Data
Authors: Jalšenjak Nenad , Težak Đurđica
Published: August 2004

A simple method for determination of the counterion binding parameter (α) and aggregation number (N) from conductivity data is proposed. The method is based on fitting the values of the first derivative of conductivity (κ) versus total surfactant concentration (ct) function according to the equation derived from the mass action model (MAM) by using different conductivity models. Sodium dodecylsulphate (SDS) and dodecyltrimethylammonium bromide (DTAB) were chosen for validation of the proposed method. It was shown that the method gives a fairly accurate values for micellisation parameters of SDS (N=51–64, α=0.74–0.75) and DTAB (N=56–62, α=0.77–0.79), both in good agreement with the literature data. In addition, application of the proposed method does not require the value of the critical micelle concentration (cmc).
Mechanism and use of the commercially available viability stain, BacLight
Authors: Stocks S. M.
Published: August 2004

Background

BacLight (Molecular Probes, Eugene, OR, USA) is a popular fluorescence‐based two‐component stain for determining bacterial cell viability. The main purpose of this work was to fully elucidate the mechanism and to determine why it is sometimes reported that cells stain simultaneously live and dead.

Methods

Solutions of DNA were stained with the two components, propidium iodide (PI) and SYTO9, in different combinations, and fluorescence spectra were collected.

Results

KPI and KSYTO9 were approximately 3.7 × 105/M and 1.8 × 105/M. SYTO9 emissions were stronger and overlapped those of PI. Fluorescence resonance energy transfer from SYTO9 to PI was observed. It was, even under normal conditions, possible for DNA bound SYTO9 to have a component in the red region equal to that of DNA bound PI. Potentially confusing emissions were also found to occur when PI was not in sufficient excess to saturate nucleic acid (>0.4 M PI to 1 M DNA base pairs).

Conclusions

The mechanism is a combination of displacement of SYTO9 by PI and quenching of SYTO9 emissions by fluorescence resonance energy transfer. Confusing results can occur if the relative intensities of the stains or the concentration of PI relative to nucleic acid are not properly accounted for. © 2004 Wiley‐Liss, Inc.
Three Chloro(trifluoromethyl)pyridines as Model Substrates for Regioexhaustive Functionalization
Authors: Cottet Fabrice , Schlosser Manfred
Published: August 2004

As a further test of the concept of regioexhaustive functionalization, 2‐chloro‐6‐(trifluoromethyl)pyridine, 2‐chloro‐5‐(trifluoromethyl)pyridine and 3‐chloro‐4‐(trifluoromethyl)pyridine were each converted into the three possible carboxylic acids 2, 4, 6, 8, 10, 12, 16, 17 and 20. This was achieved by employing several, but not all of the organometallic “toolbox methods”: transformation of a more basic organometallic species into a less basic isomer by transmetalation‐equilibration, site discriminating deprotonation with lithium N,N‐diisopropylamide or lithium 2,2,6,6‐tetramethylpiperidide, regio‐divergent iodine migration and steric screening of acidic positions by a bulky trialkylsilyl group. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
The (Schiff base)vanadium(V) Complex Catalyzed Oxidation of Bromide − A New Method for the in situ Generation of Bromine and Its Application in the Synthesis of Functionalized Cyclic Ethers
Authors: Greb Marco , Hartung Jens , Köhler Franz , Špehar Kristina , Kluge Ralph , Csuk René
Published: August 2004

(Schiff base)vanadium(V) complexes 5 with tridentate imine auxiliaries served as catalysts for the oxidation of Br− with tert‐butyl hydroperoxide (TBHP) in nonaqueous solvents. This reaction has been applied for the conversion of substituted 4‐penten‐1‐ols into 5‐exo‐bromo‐cyclized products, including a diastereomerically pure heterocyclic precursor used in a synthesis of the all‐trans‐configured 2,3,4,5‐substituted tetrahydrofuran 2‐epi‐magnosalicin. Treatment of ψ‐substituted bis(homoallylic) alcohols with the reagent combination of pyHBr, TBHP, and a vanadium(V) catalyst 5 afforded 6‐endo‐cyclized products, i.e. brominated tetrahydropyrans, as major compounds. The results from 51V NMR, ESI‐MS, and supporting reactivity‐selectivity studies indicated that the mechanism of the new bromination reaction consists of vanadium‐dependent and vanadium‐independent steps. A (Schiff base)vanadium(V) compound 5 is required for activation of TBHP via in situ formation of the corresponding tert‐butylperoxy complex. This reagent oxidizes Br−, which under the reaction conditions provides Br2 as the active brominating reagent. The molecular bromine generated thus is released into the solution at a steady rate and serves as a reagent for the synthesis of β‐brominated cyclic ethers from bis(homoallylic) alcohols in a second, vanadium‐independent step. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Green Self‐Assembling Porphyrins and Chlorins as Mimics of the Natural Bacteriochlorophylls c, d, and e
Authors: Balaban Teodor Silviu , Linke‐Schaetzel Myriam , Bhise Anil Dnyanoba , Vanthuyne Nicolas , Roussel Christian
Published: August 2004

Novel porphyrins and chlorins that self‐assemble in nonpolar solvents in a manner similar to that of the bacteriochlorophylls c, d, and e have been synthesized by a common protective group approach. The supramolecular assemblies have broad and red‐shifted absorption spectra in comparison to those of the monomeric building blocks. The presence of a carbonyl group in conjugation with the tetrapyrrolic macrocycle produces green colors both in the free bases and in their zinc complexes, which, after self‐assembly, are thus perfect artificial mimics of the chlorosomal antennas encountered in green photosynthetic bacteria. Enantiopure building blocks produce large helical aggregates with M or P helicity determined by the chirality of the 1‐hydroxyethyl substituent. It is demonstrated that the groups essential for self‐organization to occur − namely the hydroxy group, the zinc metal atom and the carbonyl group − do not have to be collinear, as has been presumed until now. Surprisingly, the chlorin derivative does not show hyperchromicity relative to similarly substituted porphyrins. This fact allows us to conclude that the more readily available porphyrins may be used for efficient artificial antennas of potential use in solar devices; otherwise it is necessary to increase the number of synthetic steps in order to incorporate into chlorins the annulated cyclopentanone ring, a structural feature carefully optimized by evolution in all (bacterio)chlorophylls. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
New Efficient Synthesis of 1,2,4‐Triazolo[5,1‐b]quinazolin‐9(3H)‐ones via a Tandem Aza‐Wittig/Heterocumulene‐Mediated Annulation
Authors: Ding Ming‐Wu , Chen Yun‐Feng , Huang Nian‐Yu
Published: August 2004

The carbodiimides 2, obtained from aza‐Wittig reactions of iminophosphorane 1 with aromatic isocyanates, react with hydrazine to give, selectively, the 3‐amino‐2‐arylaminoquinazolin‐4(3H)‐ones 4. Reaction of 4 with triphenylphosphane, hexachloroethane and triethylamine produces iminophosphoranes 5. A tandem aza‐Wittig reaction of iminophosphorane 5 with isocyanate or acyl chloride generates the 1,2,4‐triazolo[5,1‐b]quinazolin‐9(3H)‐ones 7 or 9, respectively, in satisfactory yield. The aza‐Wittig reaction of iminophosphorane 5 with CS2 or CO2 gives the 1,2,4‐triazolo[5,1‐b]quinazolin‐9(3H)‐ones 14 or 17, respectively. Further S‐alkylation of 14 produces the 2‐alkylthio‐1,2,4‐triazolo[5,1‐b]quinazolin‐9(3H)‐one 15. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
New Monodentate P,C‐Stereogenic Bicyclic Phosphanes: 1‐Phenyl‐1,3a,4,5,6,6a‐hexahydrocyclopenta[b]phosphole and 1‐Phenyloctahydrocyclopenta[b]phosphole
Authors: Pakulski Zbigniew , Demchuk Oleg M. , Frelek Jadwiga , Luboradzki Roman , Pietrusiewicz K. Michał
Published: August 2004

Racemic1‐phenyl‐1,3a,4,5,6,6a‐hexahydrocyclopenta[b]phosphole (4) was separated into enantiomerically pure 1‐phenyl‐1,3a,4,5,6,6a‐hexahydrocyclopenta[b]phosphole 1‐oxides [(RP)‐6 and (SP)‐6] by an oxidative resolution procedure involving treatment of 4 with menthyl bromoacetate, crystallization of the resulting diastereoisomeric phosphonium bromides 8, and stereoselective hydrolysis of the diastereomerically pure salts to the corresponding enantiomerically pure phosphane oxides. Stereoretentive reduction of P=O in (RP)‐6 gave enantiomerically pure (SP)‐4. Hydrogenation of (SP)‐6 and subsequent reduction of P=O afforded saturated 1‐phenyloctahydrocyclopenta[b]phosphole [(RP)‐5]. Monophosphanes (SP)‐4 and (RP)‐5 were tested as chiral ligands and catalysts in model asymmetric hydrogenation and C−C bond‐forming reactions. Enantioselectivities of up to 95% were observed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)