bluuebunny/crossref_metadata_2025 huggingface dataset:
A rapid microwave‐assisted solvent extraction method for assessment of stabilizer concentration in crosslinked polydimethylsiloxane
Authors: Fateh‐Alavi K. , Karlsson S. , Gedde U. W.
Published: June 2004

Crosslinked polydimethylsiloxanes were prepared containing 0.05 to 0.2 wt % of either a phenolic antioxidant (Irganox® 1010) or a hindered amine stabilizer (Tinuvin® 144). The stabilizer concentration was assessed by HPLC and UV‐Vis spectroscopy of Soxhlet and microwave‐assisted solvent extracts. Almost complete recovery of stabilizer was achieved with Soxhlet extraction. High stabilizer recovery was achieved when acetone was used as the solvent in the microwave‐assisted extraction. HPLC was shown to be an efficient method for determining the concentration of Irganox 1010. For Tinuvin 144 the selectivity of both UV‐Vis spectroscopy and HPLC was poor, leading to imprecise evaluation of the antioxidant concentration. The loss of stabilizer by migration from polymer to hot water (75 and 95°C) was monitored for the systems stabilized with Irganox 1010 and the diffusion coefficient of the antioxidant in the polymer was determined. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2185–2192, 2004
Compatibility in immiscible polysulfone/poly(ethylene terephthalate) blends
Authors: Retolaza A. , Eguiazábal J. I. , Nazábal J.
Published: June 2004

Polysulfone (PSU)/poly(ethylene terephthalate) (PET) blends were obtained by direct injection molding across the composition range. Their phase behavior, thermal properties, morphology, and mechanical properties were measured. The blends were composed of a pure PSU amorphous phase and either a pure PET phase in PSU‐poor blends, or a PET‐rich phase with some dissolved PSU in PSU‐rich blends. The morphology of the dispersed phase was mostly spherical with some elongated particles in the PET‐rich blends. A slight synergistic behavior was observed in the Young's modulus, mainly in the 90/10 blend, which is probably due to orientation effects. The presence of some broken particles indicated some interfacial adhesion. The ductility values were approximately linear with composition. This was generally the case in PSU‐rich blends, and was attributed to the higher level of PSU in the PET‐rich phase. Although embrittlement was seen in blends with 30% of the second component, the ductility of the two pure components did not significantly decrease after annealing due to the presence of low amounts (up to 10%) of another component of the blend. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2193–2200, 2004
Epoxy‐montmorillonite clay nanocomposites: Synthesis and characterization
Authors: Nigam Vineeta , Setua D. K. , Mathur G. N. , Kar Kamal K.
Published: June 2004

Nanocomposites of epoxy resin with montmorillonite clay were synthesized by swelling of different proportions of the clay in a diglycidyl ether of bisphenol‐A followed by in situ polymerization with aromatic diamine as a curing agent. The montmorillonite was modified with octadecylamine and made organophilic. The organoclay was found to be intercalated easily by incorporation of the epoxy precursor and the clay galleries were simultaneously expanded. However, Na‐montmorillonite clay could not be intercalated during the mixing or through the curing process. Curing temperature was found to provide a balance between the reaction rate of the epoxy precursor and the diffusion rate of the curing agent into the clay galleries. The cure kinetics were studied by differential scanning calorimetry. The exfoliation behavior of the organoclay system was investigated by X‐ray diffraction. Thermogravimetric analysis was used to determine the thermal stability, which was correlated with the ionic exchange between the organic species and the silicate layers. The morphology of the nanocomposites was evaluated by scanning electron microscopy. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2201–2210, 2004
Application of microwave irradiation for synthesis of novel optically active poly(amide imides) derived from diacid chloride containing epiclon and L‐isoleucine with aromatic diamines
Authors: Mallakpour Shadpor , Kowsari Elaheh
Published: June 2004

Epiclon [3a,4,5,7a‐tetrahydro‐7‐methyl‐5‐(tetrahydro‐2,5‐dioxo‐3‐furanyl)‐1,3‐isobenzofurandione] or [5‐(2,5‐dioxotetrahydrofurfuryl)‐3‐methyl‐3‐cyclohexyl‐1,2‐dicarboxylic acid anhydride] (1) was reacted with L‐isoleucine (2) in acetic acid and the resulting imide acid (3) was obtained in high yield. The diacid chloride (4) was obtained from diacid derivative (3) by reaction with thionyl chloride. The polycondensation reaction of diacid chloride (4) with several aromatic diamines such as 4,4′‐sulfonyldianiline (5a), 4,4′‐diaminodiphenyl methane (5b), 4,4′‐diaminodiphenylether (5c), p‐phenylenediamine (5d), m‐phenylenediamine (5e), 2,4‐diaminotoluene (5f), and 4,4′‐diaminobiphenyl (5g) was developed by using a domestic microwave oven in the presence of a small amount of a polar organic medium such as o‐cresol. The polymerization reactions were also performed in two other different methods: low‐temperature solution polycondensation and reflux conditions. A series of optically active poly(amide imides) with inherent viscosity of 0.12–0.30 dL/g were obtained. All of the above polymers were fully characterized by IR, elemental analyses, and specific rotation techniques. Some structural characterizations and physical properties of these optically active poly(amide imides) are reported. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2218–2229, 2004
A novel modification on melt intercalation via exothermal MMT
Authors: Wang Xin , Lin Jingjing , Wang Xuyun , Wang Zhaobo
Published: June 2004

This article presented a novel modification on the melt intercalation. Montmorillonite (MMT) with exothermal enthalpy effect was prepared by the compounding of MMT with AIBN in solution. An exfoliated polystyrene (PS)/MMT nanocomposites could be obtained by the introduction of exothermal MMT via melt mixing, and the comparison with the counterpart indicated the exfoliation of MMT was accelerated by the in situ exothermal enthalpy and nitrogen released during melt intercalation. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2230–2236, 2004
Compatibilization of a polyolefin blend through covalent and ionic coupling of grafted polypropylene and polyethylene. II. Morphology
Authors: Colbeaux Aimeline , Fenouillot Françoise , Gerard Jean‐François , Taha Mohamed , Wautier Henri
Published: June 2004

The morphology of a polypropylene/polyethylene (PP/PE) blend and a maleic anhydride modified PP and PE (PPg/PEg) blend was studied. The initial morphology, at the extruder die, after the melt blending into a twin‐screw extruder, was first characterized. Then, the evolution of this initial morphology was followed after a injection molding operation, and during annealing in an oven at 200°C. The influence of the compatibilization of the blend by coupling reactions through covalent (with 1,12‐diaminododécane) and ionic reactions (with zinc acetate and sodium hydrogenocarbonate) was also investigated. At the extruder die, the viscosity ratio proved to be a determinant factor governing the dispersed phase diameter of the droplets, and as a second factor, the addition of small amounts of coupling‐agents together with (PPg/PEg) to (PP/PE) resulted in a decrease of the diameter of the droplets. The injection molding of these initial blends resulted in important coalescence and in an elongation of the dispersed phase. This was observed for the non compatibilized and also for some of the compatibilized blends. The ionic coupling showed a good stabilization of the morphology. Finally, the morphology of the non compatibilized blends was found to be instable when the material was annealed at 200°C. The average size of the dispersed phase increased. The coupling reactions delayed the occurrence of the coalescence about 5 min and limited its effects. The extent of the coarsening depended strongly on the composition of the blend and on the nature of the coupling. Still, the ionic agents appeared more effective. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2237–2244, 2004
Acrylamide‐grafted‐acacia gum polymer matrix tablets as erosion‐controlled drug delivery systems
Authors: Toti Udaya S. , Soppimath Kumaresh S. , Mallikarjuna Nadagouda N. , Aminabhavi Tejraj M.
Published: June 2004

Acrylamide was grafted onto acacia gum in different ratios (1 : 1, 1 : 3, and 1 : 5). The graft copolymers formed were characterized by FTIR, rheological measurements, and differential thermal analysis. Tablets were prepared from these polymers loaded with two antihypertensive drugs, viz., diltiazem hydrochloride and nifedipine. The in vitro release experiments were carried out in simulated gastric and intestinal conditions. The graft copolymer prepared in the ratio 1 : 5 of acacia gum : acrylamide matrix was found to be a suitable matrix to investigate the controlled release of diltiazem hydrochloride and nifedipine. The drug release continued up to 6 and 14 h, respectively, for diltiazem hydrochloride and nifedipine. The release mechanism was investigated by using the mathematical equations proposed by Higuchi, Hixson‐Crowell, and Kopcha. Based on the release kinetics data, a correlation was attempted between the erosion‐controlled release and the dissolution‐controlled release. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2245–2253, 2004
Methanol‐ and ethanol‐induced convex deformation and macrovoid formation of poly(methyl methacrylate)
Authors: Lin C. B. , Chen C. S. , Chen Zhi‐Hong , Su Nan‐Ching
Published: June 2004

Methanol‐ and ethanol‐induced convex deformation and macrovoid formation in poly(methyl methacrylate) (PMMA) through sandwich structures, consisting of polycarbonate (PC)/PMMA/PC was investigated. The sandwich structures had a circular hole on the outer PC layer, which allowed the solvent to contact with PMMA. Both single‐convex and double‐convex deformations of the PMMA layer were produced, depending upon the hole diameter. For a fixed hole diameter, there was an optimum PMMA thickness, which produced maximum curvature for the double‐convex deformation. The physical mechanism for these phenomena can be well explained by the relative strength of the swelling stress and the deformation resistance of the PMMA layer. We also used the wet phase‐inversion method to produce porous convex deformation for the sandwich structures. The size, number, and location of the convex pores can be prescribed. This may have potential applications in local filtering and other areas. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2254–2261, 2004
Formation of multilayer poly(acrylic acid)/poly(vinylidene fluoride) composite membranes for pervaporation
Authors: Lin Dar‐Jong , Chang Cheng‐Liang , Shaw Horng‐Yue , Jeng Yi‐Su , Cheng Liao‐Ping
Published: June 2004

Dual‐ and multilayer composite membranes, consisting of poly(acrylic acid) (PAA) and poly(vinylidene fluoride) (PVDF), were synthesized by the plasma‐induced polymerization technique. The dual‐layer membrane had a dense PAA layer grafted onto a microporous PVDF substrate, whereas in the multilayer membranes, the grafted PAA and the PVDF layers were arranged in an alternating sequence (e.g., PAA/PVDF/PAA and PAA/PVDF/PAA/PVDF/PAA). These membranes were used in a pervaporation process to separate ethanol–water solutions. For the dual‐layer membranes, the results indicated that the separation factor increased and the permeation flux decreased with increasing amounts of grafted PAA. For the case of grafting yield < 0.6 mg/cm2, the composite membrane demonstrated poor separation. As the grafting yield reached 0.85 mg/cm2, a sharp increase of the separation factor was observed. For the multilayer membranes, the pervaporation performances were very good, with high separation factors (on the order of 100) and reasonable permeation fluxes over a wide ethanol concentration range. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2266–2274, 2004
Preparation and characterization of ball‐milled Nafion® powders for membrane applications
Authors: Haynes Shawn D. , Mitchell Brian S.
Published: June 2004

A method for producing Nafion® powder from commercially available pellets, and using this powder to produce membranes, is described. A description of particle size distribution, chemical composition, and thermal properties of Nafion® powders prepared by high‐energy ball milling of pellets is given. Nafion® powders prepared in this manner exhibit thermal behavior similar to that of the precursor pellets; however, traces of iron from the milling materials are shown to be present through transmission electron microscopy analysis of the particles. The membranes prepared by hot pressing of the Nafion® powders also show thermal behavior similar to that of the precursor pellet materials. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2275–2281, 2004
Influence of interchain forces and supermolecular structure on the drawing behavior of nylon 66 fibers in the presence of supercritical carbon dioxide
Authors: Hu Xianbo , Lesser Alan J.
Published: June 2004

The drawing behavior and mechanical properties of as‐spun and highly oriented nylon 66 fibers drawn in supercritical carbon dioxide (SCCO2) were investigated. Conditions including different temperatures, CO2 pressures, and plasticizers with different polarity were systematically studied. Results indicate that CO2 is an efficient plasticizer for as‐spun nylon 66 fibers as shown by decreases in the draw stress. In contrast, CO2 shows only a slight influence on the drawability of highly oriented nylon 66 fiber. The effect of other plasticizers such as water, methanol, and ethanol on the drawability of nylon 66 fibers is very similar to that of CO2. Tenacity and modulus of one‐stage drawn fibers were less than 0.8 and 5.0 GPa, respectively. Fibers with the highest tenacity and modulus, 0.96/5.04 and 1.06/5.04 GPa, were obtained by two‐stage drawing in SCCO2 from as‐spun and drawn nylon 66 fibers, respectively. The main reason for the extremely low draw ratios (<6.0) of nylon 66 fibers was the presence of hydrogen bonds in the crystalline phase. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2282–2288, 2004
Polystyrene and polyester polyurethane elastomer blends compatibilized by SMA
Authors: Cassu Silvana Navarro , Felisberti Maria Isabel
Published: June 2004

Blends of polystyrene (PS) with polyester polyurethane elastomer (PU‐es) were compatibilized by addition of poly(styrene‐co‐maleic anhydride) (SMA) containing 7 wt % of maleic anhydride. Binary nonreactive (PS/PU‐es) blends, binary reactive (SMA/PU‐es) blends, and ternary reactive blends (PS/SMA/PU‐es) were prepared with 10 and 20 wt % of PU‐es. The maleic anhydride content in the ternary reactive blends was varied through addition of different SMA amounts from 0.5 to 5 wt %. Polyurethane in the blends was crosslinked by using dicumyl peroxide or sulfur to improve its mechanical properties. The experimental processing conditions, such as temperature and rotor speed in an internal mixer, were analyzed before blend preparation by processing the individual polymers, PS and SMA, and the PS/PU‐es nonreactive blend (90/10), to prevent the degradation of the polymer during melt mixing and to assure macroscopic homogeneity. The torque behavior during the mixture indicated a grafting copolymerization, which was responsible for the significant drop of the PU‐es domain size in the glassy matrix, as observed by scanning electronic microscopy (SEM). The miscibility of the glassy matrix, which was shown to be dependent on the composition and the phase behavior of ternary blends, became very complex as the SMA concentration increased, as concluded from dynamical–mechanical analysis. Blends containing 20 wt % of PU‐es presented an increase up to a factor of 2 in the deflection at break in relation to PS. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2297–2304, 2004
Metabolic effects and the methylenetetrahydrofolate reductase (MTHFR) polymorphism associated with neural tube defects in southern Brazil
Authors: Félix Têmis Maria , Leistner Sandra , Giugliani Roberto
Published: June 2004

BACKGROUND

The importance of metabolic factors in neural tube defects (NTDs) has been the focus of many investigations. Several authors have suggested that abnormalities in homocysteine metabolism, such as hyperhomocysteinemia, folate deficiency, and low vitamin B12, may be responsible for these malformations and that both nutritional factors and genetic abnormalities are associated with them.

METHODS

We conducted a case‐control study to investigate the influence of biochemical and genetic factors in NTDs in infants in southern Brazil. Levels of folate, vitamin B12, total homocysteine (t‐Hcy) and the 677C>T and 1298A>C polymorphisms of the MTHFR gene were analyzed in 41 NTD child–mother pairs and 44 normal child–mother control pairs.

RESULTS

Subjects in the case group had a higher mean blood folate level than those in the control group. The level of vitamin B12 was lower in mothers in the NTD group than in control mothers (p = 0.004). The level of t‐Hcy was not different in the two groups, but t‐Hcy and vitamin B12 were correlated (p = 0.002). There was no difference in the genotype distribution for 677C>T and 1298A>C polymorphisms of MTHFR in the case and control pairs. The level of t‐Hcy was correlated with 677TT.

CONCLUSIONS

Despite the small sample in this study, we suggest that low vitamin B12 and, consequently, hyperhomocysteinemia are important risk factors for NTDs in our population. Birth Defects Research (Part A), 2004. © 2004 Wiley‐Liss, Inc.
Maternal vitamin B‐6 and folate status and risk of oral cleft birth defects in the Philippines
Authors: Munger Ronald G. , Sauberlich Howerde E. , Corcoran Christopher , Nepomuceno Buena , Daack‐Hirsch Sandra , Solon Florentino S.
Published: June 2004

BACKGROUND

Vitamin deficiencies induce oral clefts in animal experiments, but the role of specific nutrients in human oral clefts is uncertain.

METHODS

Associations between maternal vitamin B‐6 and folate status and risk of nonsyndromic cleft lip, with or without cleft palate (CL/P), were examined in case–control studies at two sites in the Philippines—Negros Occidental and Davao. Cases were mothers of affected children and control mothers were those who had no children with oral clefts.

RESULTS

The risk of having a CL/P‐affected child increased with increasing tertile of vitamin B‐6 deficiency in both Negros Occidental and Davao (odds ratios [ORs] and 95% confidence intervals [CIs] for sites combined = 1.0 [reference], OR, 2.94; 95% CI, 1.51–5.73; OR, 4.98; 95% CI, 2.56–9.67). Poor B‐6 status had a stronger association with CL/P among mothers with lower versus higher plasma folate levels. Increasing tertiles of plasma folate were marginally associated with an increased risk of clefts in both sites combined (1.0 [reference]; OR, 1.58; 95% CI, 0.93–2.68; OR, 1.59; 95% CI, 0.94–2.70). Increasing tertiles of erythrocyte folate were associated with a decreased risk of CL/P in Negros Occidental (1.0 [reference]; OR, 0.34; 95% CI, 0.13–0.90; OR, 0.46; 95% CI, 0.20–1.09) and an increased risk in Davao (1.0 [reference]; OR, 1.23; 95% CI, 0.54–2.81; OR, 4.85; 95% CI, 2.24–10.50). The inconsistent associations between folate status and CL/P risk appeared to be a result of statistical interaction between folate, vitamin B‐6, and case–control status that produced different results in study areas of higher versus lower prevalence of vitamin B‐6 deficiency.

CONCLUSIONS

Poor maternal vitamin B‐6 status was consistently associated with an increased risk of CL/P at two sites in the Philippines. Folate‐CL/P associations were inconsistent and may be related to the vitamin B‐6 status or other characteristics of the populations under study. Birth Defects Research (Part A), 2004. © 2004 Wiley‐Liss, Inc.
Thymidylate synthase repeat polymorphisms and risk of neural tube defects in a population from the northern United Kingdom
Authors: Wilding Craig S. , Relton Caroline L. , Sutton Matthew J. , Jonas Pat A. , Lynch Sally‐Ann , Tawn E. Janet , Burn John
Published: June 2004

BACKGROUND

A 28‐bp repeat polymorphism in the 5′UTR of the thymidylate synthase (TYMS) gene represents a candidate risk factor for neural tube defects (NTDs) due to involvement in folate‐dependent homocysteine metabolism. Non‐Hispanic, white, U.S. citizens carrying at least one 2× 28‐bp repeat allele have recently been shown to be at a four‐fold increased risk of spina bifida (SB). We investigated the association between this polymorphism and risk of NTD in families affected by NTDs and controls from the northern United Kingdom (UK).

METHODS

PCR was performed on genomic DNA extracted from blood or mouth swabs of family members affected by NTDs (mothers, fathers, and cases), and unaffected controls (mothers and infants) to determine the number of 28‐bp repeat units within the promoter region of TYMS. Case–control and TDT analyses of the influence of TYMS genotype on risk of NTD, or NTD pregnancy, were conducted.

RESULTS

Odds ratio (OR) analysis indicated that individuals carrying the 2× 28‐bp repeat allele either in homozygous or heterozygous form, are not at increased risk of NTDs, or of having an NTD affected pregnancy. Control population allele frequencies are seen to be markedly different between the U.S. controls and those in this study.

CONCLUSIONS

TYMS polymorphism appears to be not universally associated with NTD risk across Caucasian samples. The elevated risk of spina bifida in U.S. samples appears to be driven by an unusually low risk allele (2× 28 bp) frequency in control samples. Family based (TDT) testing of U.S. samples is therefore advocated. Birth Defects Research (Part A), 2004. © 2004 Wiley‐Liss, Inc.
Is lack of morning sickness teratogenic? A prospective controlled study
Authors: Boskovic Rada , Rudic Natasha , Danieliewska‐Nikiel Barbara , Navioz Yvette , Koren Gideon
Published: June 2004

BACKGROUND

Case‐control studies have suggested that the nausea and vomiting of pregnancy (NVP) may have a protective effect against specific malformations. These suggestions have been interpreted as if the lack of NVP may put mothers at an increased teratogenic risk.

METHODS

A prospective, cohort‐controlled study was done comparing pregnancy outcome in women not experiencing NVP with those experiencing NVP at two levels of clinical severity. Women who called the Motherisk program about first‐trimester exposure to drugs and who had not experienced NVP were included as the study group. The NVP Healthline enrolled two control groups of women with NVP treated with a doxylamine‐pyridoxine combination for morning sickness. These women were exposed during the first trimester of gestation to either higher than the standard dose (5–12 tablets/day) or a standard dose (1–4 tablets/day) of doxylamine‐pyridoxine. The women in all three groups were followed up four to six months after the expected date of birth to ascertain pregnancy outcomes and child health.

RESULTS

There were no major malformations among offspring of 130 women not experiencing NVP. There were two major malformations among 246 women experiencing NVP. The two control groups of women with NVP had similar distributions of gestational ages, birth rates, as well as rates of miscarriages and stillbirths, as in the no‐NVP group.

CONCLUSIONS

This study did not show an association between lack of NVP and an increase in the overall rates of major malformations. Birth Defects Research (Part A), 2004. © 2004 Wiley‐Liss, Inc.
Epidemiologic characteristics of anotia and microtia in California, 1989–1997
Authors: Shaw Gary M. , Carmichael Suzan L. , Kaidarova Zhanna , Harris John A.
Published: June 2004

BACKGROUND

There is a paucity of epidemiologic information about the external ear malformations anotia and microtia.

METHODS

Using data from a large population‐based registry, we explored prevalences and maternal/infant characteristics associated with anotia and microtia. Data were derived from the California Birth Defects Monitoring Program, a population‐based active surveillance system for collecting information on infants and fetuses with congenital malformations using multiple source ascertainment. Approximately 2.5 million births (live‐born and stillborn) occurred during the ascertainment period, 1989–1997. Information on maternal and infant/fetal characteristics was obtained from California birth certificate and fetal death files.

RESULTS

The prevalence of anotia/microtia was 2.50 per 10,000 live births and stillbirths. Isolated cases, i.e., those live births and stillbirths with no other accompanying anomaly diagnoses, revealed a prevalence of 0.63 per 10,000, whereas among nonisolated cases, the prevalence was 1.53 per 10,000 live births and stillbirths. Prevalences of isolated anotia/microtia were substantially higher among U.S.‐born Hispanics, foreign‐born Hispanics, and Asians compared to non‐Hispanic whites, with relative risks ranging from three‐ to seven‐fold. Similar prevalences for maternal race/ethnicity (except for Asians) were observed for live births and stillbirths with nonisolated cases of anotia/microtia, but the magnitude of risks were lower than those observed for isolated cases. Prevalence of nonisolated anotia/microtia was substantially lower among women whose education was 12 years or more.

CONCLUSIONS

These data reveal descriptive epidemiologic features of anotia/microtia most notably substantial risks associated with race/ethnic groups and lower maternal education. Additional study for factors associated with these characteristics could reveal clues for the etiology of these ear anomalies. Birth Defects Research (Part A), 2004. © 2004 Wiley‐Liss, Inc.
Developmental consequences of abnormal folate transport during murine heart morphogenesis
Authors: Tang Louisa S. , Wlodarczyk Bogdan J. , Santillano Daniel R. , Miranda Rajesh C. , Finnell Richard H.
Published: June 2004

BACKGROUND

Folic acid is essential for the synthesis of nucleotides and methyl transfer reactions. Folic acid–binding protein one (Folbp1) is the primary mediator of folic acid transport into murine cells. Folbp1 knockout mouse embryos die in utero with multiple malformations, including severe congenital heart defects (CHDs). Although maternal folate supplementation is believed to prevent human conotruncal heart defects, its precise role during cardiac morphogenesis remains unclear. In this study, we examined the role of folic acid on the phenotypic expression of heart defects in Folbp1 mice, mindful of the importance of neural crest cells to the formation of the conotruncus.

METHODS

To determine if the Folbp1 gene participates in the commitment and differentiation of the cardiomyocytes, relative levels of dead and proliferating precursor cells in the heart were examined by flow cytometry, Western blot, and immunohistostaining.

RESULTS

Our studies revealed that impaired folic acid transport results in extensive apoptosis‐mediated cell death, which concentrated in the interventricular septum and truncus arteriosus, thus being anatomically restricted to the two regions of congenital heart defects. Together with a reduced proliferative capacity of the cardiomyocytes, the limited size of the available precursor cell pool may contribute to the observed cardiac defects. Notably, there is a substantial reduction in Pax‐3 expression in the region of the presumptive migrating cardiac neural crest, suggesting that this cell population may be the most severely affected by the massive cell death.

CONCLUSIONS

Our findings demonstrate for the first time a prominent role of the Folbp1 gene in mediating susceptibility to heart defects. Birth Defects Research (Part A), 2004. © 2004 Wiley‐Liss, Inc.
Developmental evaluation of children born to mothers occupationally exposed to waste anesthetic gases
Authors: Ratzon Navah Z. , Ornoy Asher , Pardo Asher , Rachel Margolin , Hatch Maureen
Published: June 2004

BACKGROUND

The etiology of developmental delay in children is frequently unknown. Increasing evidence supports the possibility that environmental and occupational factors might be part of the basis for such delays. This study focuses on the development of children born to mothers who were exposed during their pregnancy to waste anesthetic gases.

METHODS

The study population included 40 children aged 5–13 years born to female anesthesiologists and nurses working in operating rooms (OpRs) exposed to waste anesthetic gases, and 40 unexposed children born to female nurses and physicians who worked in hospitals during their pregnancy but did not work in OpRs. The unexposed group was matched for children's age and gender and maternal occupation (nurses vs. doctors). By means of standardized developmental tests, the present study population was evaluated for their medical and neurodevelopmental state. Questionnaires were given for the detection of attention and activity levels as perceived by the parents. Additional questionnaires dealt with information concerning developmental milestones, maternal and fetal morbidity, and gynecological history.

RESULTS

No differences were noted between the groups as newborns or in developmental milestones at the age of 5–13 years; however, the mean score of gross motor ability was significantly lower in the exposed versus the unexposed group. Additionally, the mean score of the DSM‐III‐R Parent‐Teacher Questionnaire (PTQ) (i.e., measure of inattention/hyperactivity) was higher in the exposed group. The level of exposure, as measured by the number of weekly hours in the OpRs, was significantly and negatively correlated with fine motor ability and the score of IQ performance.

CONCLUSIONS

Our study supports the hypothesis that occupational exposure to anesthetic gases might be a risk factor for minor neurological deficits of children born to mothers who work in OpRs and therefore indicates the need for more studies in this area and perhaps more caution among OpR pregnant women and employers. Birth Defects Research (Part A), 2004. © 2004 Wiley‐Liss, Inc.
Rubella virus and birth defects: Molecular insights into the viral teratogenesis at the cellular level
Authors: Atreya C.D. , Mohan K.V.K. , Kulkarni S.
Published: June 2004

BACKGROUND

In utero rubella virus (RV) infection of a fetus can result in birth defects that are often collectively referred to as congenital rubella syndrome (CRS). In extreme cases, fetal death can occur. In spite of the availability of a safe and effective vaccine against rubella, recent worldwide estimates are that more than 100,000 infants are born with CRS annually.

RECENT PROGRESS

Recently, several significant findings in the field of cell biology, as well as in the RV replication and virus‐cell interactions, have originated from the authors' laboratory, and other researchers have provided insights into RV teratogenesis. It has been shown that 1) an RV protein induces cell‐cycle arrest by generating a subpopulation of tetraploid nuclei (i.e., 4N DNA) cells, perhaps representative of the tetraploid state following S phase in the cell cycle, due to its interaction with citron‐K kinase (CK); 2) RV infection induces apoptosis in cell culture, and 3) CK functional perturbations lead to tetraploidy, followed by apoptosis, in specific cell types.

CONCLUSIONS

Based on several similarities between known RV‐associated fetal and cellular manifestations and CK deficiency–associated phenotypes, it is reasonable to postulate that P90‐CK interaction in RV‐infected cells interferes with CK function and induces cell‐cycle arrest following S phase in a subpopulation, perhaps representative of tetraploid stage, which could lead to subsequent apoptosis in RV infection. Taking all these observations to the fetal organogenesis level, it is plausible that P90‐CK interaction could perhaps be one of the initial steps in RV infection–induced apoptosis‐associated fetal birth defects in utero. Birth Defects Research (Part A), 2004. © 2004 Wiley‐Liss, Inc.
A study of the conformations of valinomycin in solution phase
Authors: Wang Feng , Zhao Chunxia , Polavarapu Prasad L.
Published: June 2004

Vibrational absorption and vibrational circular dichroism (VCD) spectra of valinomycin are measured, in different solvents, in the ester and amide carbonyl stretching regions. The influence of cations, namely Li+, Na+, K+, and Cs+, in methanol‐d4 solvent is also investigated. Ab initio quantum mechanical calculations using density functional theory and 6–31G* basis set are used to predict the absorption and VCD spectra. A bracelet‐type structure for valinomycin that reproduces the experimental absorption and VCD spectra in inert solvents is identified. For the structure of valinomycin in polar solvents, a propeller‐type structure was optimized, but further investigations are required to confirm this structure. A symmetric octahedral environment for the ester carbonyl groups in the valinomycin–K+ complex is supported by the experimental VCD spectra. The results obtained in the present study demonstrate that even for large macrocyclic peptides, such as valinomycin, VCD can be used as an independent structural tool for the study of conformations in solution. © 2004 Wiley Periodicals, Inc. Biopolymers, 2004
Detection of single nucleotide variations by a hybridization proximity assay based on molecular beacons and luminescence resonance energy transfer
Authors: Root Douglas D. , Vaccaro Carlos , Zhang Zhiling , Castro Miguel
Published: June 2004

A powerful combination of molecular beacon and luminescence resonance energy transfer technology reveals alterations in nucleic acid structure by as little as a single nucleotide in a novel hybridization proximity assay. The assay measures the length of a single‐stranded target when a terbium chelate‐labeled molecular beacon hybridizes to one side of the nucleic acid segment to be measured and an acceptor probe carrying a convention fluorophore hybridizes to the opposite end of the target. Using a test sequence shortened incrementally by deleting single nucleotides, this assay reports a nearly linear relationship between sequence length and the distance separating acceptor and donor probes. Consequently, this assay can be used to detect alternative splicing, allele types, rearrangements, insertion, and deletion events by measuring separation distances within a predefined region. Furthermore, the use of terbium chelates in molecular beacons can produce exceptionally high signal‐to‐background ratios compared to the use of conventional fluorophores. Principles of optimal probe design are investigated experimentally and by computational simulations of plausible molecular beacon folding. Some molecular beacon designs form dimers that reduce their maximal response to target sequences. A simple assay to detect such dimers is reported as a tool to help improve the design of molecular beacons. Optimally designed molecular beacons with terbium chelates and hybridization proximity assays are expected to expand their applications in the analysis and screening of genetic diseases. © 2004 Wiley Periodicals, Inc. Biopolymers, 2004
Development of image analysis techniques as a tool to detect and quantify morphological changes in anaerobic sludge: II. Application to a granule deterioration process triggered by contact with oleic acid
Authors: Amaral A.L. , Pereira M.A. , da Motta M. , Pons M.‐N. , Mota M. , Ferreira E.C. , Alves M.M.
Published: June 2004

Image analysis techniques are applied to monitor the morphological changes in granular sludge present in an expanded granular sludge blanket (EGSB) reactor fed with oleic acid. Deterioration of granular sludge was monitored along the trial period by measuring the percentage of aggregates smaller than 1 mm (in terms of Feret diameter) either in terms of projected area or in terms of number of aggregates. A good correlation was obtained between these values and the percentage of aggregates smaller than 1 mm were physically sorted and quantified by the volatile suspended solid content. The ratio of total filaments length to cross‐sectional area of aggregates defined as LfA, was applied to quantify the dispersion level of the granular sludge, which increased until day 141 and remained almost invariant afterwards. LfA was sensitive to the sludge deterioration process and was able to indicate, with the anticipation of about 1 month, the most significant biomass washout episode that occurred in the trial period. A mechanism of filaments' release, detachment and selective washout was proposed to explain the action of LfA from this viewpoint. The equivalent diameter of the bottom aggregates larger than 1 mm increased with the increase on the amount of long chain fatty acids associated with the biomass by mechanisms of adsorption, precipitation, or entrapment. After a threshold value of about 200 mg COD‐LCFA gVSS (COD = chemical oxygen demand; LCFA = long chain fatty acids; VSS = volatile suspended solids), a migration of granular sludge from the bottom to a top‐floating layer was evident. © 2004 Wiley Periodicals, Inc.
High‐Pressure Synthesis and Crystal Structures of Two New Polyphosphides, NaP5 and CeP5.
Authors: Chen Xuean , Yamanaka Shoji
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
Crystal Structures of Ln2Pd2Pb (Ln: Y, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, and Lu) Compounds.
Authors: Melnyk G. , Kandpal H. C. , Gulay L. D. , Tremel W.
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
Field Emission of Electron Anions Clathrated in Subnanometer‐Sized Cages in [Ca24Al28O64]4+(4e‐).
Authors: Toda Yoshitake , Matsuishi Satoru , Hayashi Katsuro , Ueda Kazushige , Kamiya Toshio , Hirano Masahiro , Hosono Hideo
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
Crystal Structure and Magnetic Properties of ZnV2O4.
Authors: Ebbinghaus S. G. , Hanss J. , Klemm M. , Horn S.
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
Growth and Dielectric Properties of Ca3NbGa3Si2O14 Crystals.
Authors: Wang Zengmei , Yuan Duorong , Xu Dong , Lue Mengkai , Shi Xuzhong , Su Wenbin , Zhao Minglei , Wang Jinfeng , Pan Lihu
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
The Phase Relationship in the Fe—Pb—Sb Ternary System at 500 K.
Authors: Sun Zhihui , Zeng Lingming
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
Investigation of the Interaction of the Components in the Y—Si—Sb System at 670 K.
Authors: Kozlov A. Yu. , Pavlyuk V. V.
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
Investigation of Multi‐Nickel‐Substituted Tungstophosphates and Their Stability and Electrocatalytic Properties in Aqueous Media.
Authors: Jabbour Darine , Keita Bineta , Mbomekalle Israel‐Martyr , Nadjo Louis , Kortz Ulrich
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
Hydrothermal Synthesis, Crystal Structure, Solid‐State NMR Spectroscopy, and Ionic Conductivity of Na5InSi4O12, a Silicate Containing a Single 12‐Membered Ring.
Authors: Hung Ling‐I , Wang Sue‐Lein , Szu Sung‐Ping , Hsieh Chan‐Yen , Kao Hsien‐Ming , Lii Kwang‐Hwa
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
Noncentrosymmetric Cubic Thio‐ and Selenogermanates: A0.5M1.75GeQ4 (A: Ag, Cu, Na; M: Pb, Eu; Q: S, Se).
Authors: Iyer Ratnasabapathy G. , Aitken Jennifer A. , Kanatzidis Mercouri G.
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
Synthesis and Thermal Stability of Nano‐Crystalline Vanadium Disilicide.
Authors: Ma Jianhua , Gu Yunle , Shi Liang , Chen Luyang , Yang Zeheng , Qian Yitai
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
XRD and HREM Studies of Epitaxially Stabilized Hexagonal Orthoferrites LnFeO3 (Ln: Eu—Lu).
Authors: Bossak Alexei A. , Graboy Igor E. , Gorbenko Oleg Yu. , Kaul Andrey R. , Kartavtseva Maria S. , Svetchnikov Vassily L. , Zandbergen Henny W.
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
Mechanochemical Michael Reactions of Chalcones and Azachalcones with Ethyl Acetoacetate Catalyzed by K2CO3 under Solvent‐Free Conditions.
Authors: Zhang Ze , Dong Ya‐Wei , Wang Guan‐Wu , Komatsu Koichi
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
Synthesis of Chiral Aza Crown Ethers Having Exocyclic Hydroxy Groups and Their Use in Asymmetric Reduction of Ketones with Sodium Tetrahydridoborate.
Authors: Luk'yanenko N. G. , Lobach A. V. , Leus O. N.
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
Diplogelasinospora grovesii IMI 171018, a New Whole Cell Biocatalyst for the Stereoselective Reduction of Ketones.
Authors: Carballeira Jose D. , Alvarez Emilio , Campillo Mercedes , Pardo Leonardo , Sinisterra Jose V.
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
Addition of Bromotrichloromethane and Tetrachloromethane to cis‐Cyclooctene, Cyclohexene, and Norbornadiene in the Presence of Palladium(II) Complexes.
Authors: Dneprovskii A. S. , Ermoshkin A. A. , Kasatochkin A. N. , Boyarskii V. P.
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
Hydrotalcite Catalysis in Ionic Liquid Medium: A Recyclable Reaction System for Heterogeneous Knoevenagel and Nitroaldol Condensation.
Authors: Khan Faiz Ahmed , Dash Jyotirmayee , Satapathy Rashmirekha , Upadhyay Sarasij K.
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
Stevens Rearrangement of Ammonium Salts Containing 3‐Methyl‐3‐ethoxycarbonylbutanon‐2‐yl Group.
Authors: Babakhanyan A. V. , Ovsepyan V. S. , Kocharyan S. T. , Panosyan G. A.
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
Iodine/MeOH: A Novel and Efficient Reagent System for Thiocyanation of Aromatics and Heteroaromatics.
Authors: Yadav J. S. , Reddy B. V. S. , Shubashree S. , Sadashiv K.
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
One‐Carbon Chain Extension of Esters to α‐Chloroketones: A Safer Route Without Diazomethane.
Authors: Wang Dengjin , Schwinden Mark D. , Radesca Lilian , Patel Bharat , Kronenthal David , Huang Ming‐Hsing , Nugent William A.
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
Stereoselective CrCl2‐Mediated Condensation of Aldehydes with Functionalized 1,1,1‐Trichlorides: Synthesis of Trisubstituted (Z)‐Chloroolefins.
Authors: Falck J. R. , Bandyopadhyay Anish , Barma D. K. , Shin Dong‐Soo , Kundu Abhijit , Kishore R. V. Krishna
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
Chemoselective Acylation of Amines in Aqueous Media.
Authors: Naik Sarala , Bhattacharjya Gitalee , Talukdar Bandana , Patel Bhisma K.
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
Deoximation with N‐Bromosulfonamides.
Authors: Tajbaksh M. , Khazaei A. , Mahalli M. Shabani , Vaghei R. Ghorbani
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
Synthesis of 1,2‐Divinyloxypropenes from Glycerol and Acetylene in the Superbasic System CsF—NaOH—DMSO.
Authors: Trofimov B. A. , Malysheva S. F. , Gusarova N. K. , Tatarinova A. A. , Henkelmann J.
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
Chelation‐Controlled Highly Diastereoselective Catalytic Hydrogenation of γ‐Hydroxy‐α‐methylenecarboxylic Acid Esters.
Authors: Nagano Hajime , Yokota Misaki , Iwazaki Yukiko
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
A Convenient Synthesis of 2‐Methyl‐3‐oxoheptane‐1,7‐dicarboxylic Esters and Amides.
Authors: Elliott Mark C. , Gist Matthew J. , Binns Falmai , Jones Richard G.
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
Synthesis of Peroxide Monomers Based on Unsaturated Carboxylic Acids.
Authors: Fleichuk R. I. , Gevus' O. I. , Voronov S. A.
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
Preparation of Optically Pure Cross‐Conjugated Cyclopentadienones.
Authors: Eddolls Jonathan P. , Iqbal Mazhar , Roberts Stanley M. , Santoro M. Gabriella
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
A Tandem Semipinacol Rearrangement/Alkylation of α‐Epoxy Alcohols: An Efficient and Stereoselective Approach to Multifunctional 1,3‐Diols.
Authors: Hu Xiang‐Dong , Fan Chun‐An , Zhang Fu‐Min , Tu Yong Qiang
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
A Novel Azulene Synthesis from the Ramirez Ylide Involving Two Different Modes of Its Reaction with Activated Alkynes.
Authors: Higham Lee J. , Kelly P. Gabriel , Corr David M. , Mueller‐Bunz Helge , Walker Brian J. , Gilheany Declan G.
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
Lewis Acid Induced Tandem Diels—Alder Reaction/Ring Expansion as an Equivalent of a [4 + 3] Cycloaddition.
Authors: Davies Huw M. L. , Dai Xing
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
Structure and Properties of 2,2‐Dibromovinyl Trifluoromethyl Ketone.
Authors: Bozhenkov G. V. , Frolov Yu. L. , Toryashinova D. S.‐D. , Levkovskaya G. G. , Mirskova A. N.
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
Synthesis of Cinnamic Acids and Related Isosteres as Potent and Selective αvβ3 Receptor Antagonists.
Authors: Penning Thomas D. , et al. et al.
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
Copper(II)‐Catalyzed Highly Enantioselective Addition of Enamides to Imines: The Use of Enamides as Nucleophiles in Asymmetric Catalysis.
Authors: Matsubara Ryosuke , Nakamura Yoshitaka , Kobayashi Shu
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
Salicylanilides as Inhibitors of the Protein Tyrosine Kinase Epidermal Growth Factor Receptor.
Authors: Liechti Christoph , Sequin Urs , Bold Guido , Furet Pascal , Meyer Thomas , Traxler Peter
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
Pd(OAc)2‐Catalyzed Oxidative Coupling Reaction of Benzenes with Olefins in the Presence of Molybdovanadophosphoric Acid under Atmospheric Dioxygen and Air.
Authors: Tani Masayuki , Sakaguchi Satoshi , Ishii Yasutaka
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
An Exceedingly Efficient and Chemoselective Esterification with Activated Alcohols Using AlCl3/NaI/CH3CN System.
Authors: Karade N. N. , Shirodkar S. G. , Potrekar R. A. , Karade H. N.
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
Development of a Novel Ionic Support and Its Application in the Ionic Liquid Phase Assisted Synthesis of a Potent Antithrombotic.
Authors: de Kort Martin , Tuin Adriaan W. , Kuiper Suzanne , Overkleeft Hermen S. , van der Marel Gijs A. , Buijsman Rogier C.
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
Synthesis of a New Series of 4‐Chloro‐2‐mercapto‐5‐methylbenzenesulfonamide Derivatives with Potential Antitumor Activity.
Authors: Slawinski Jaroslaw
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
Beyond U0126. Dianion Chemistry Leading to the Rapid Synthesis of a Series of Potent MEK Inhibitors.
Authors: Duncia John V. , et al. et al.
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
A Novel Decyanogenative Coupling of α‐Cyanoimines Mediated by Samarium. A Facile Route to α‐Diketimines.
Authors: Thakur Ashim J. , Prajapati Dipak , Sandhu Jagir S.
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
Synthesis of Ynones by Palladium‐Catalyzed Acylation of Terminal Alkynes with Acid Chlorides.
Authors: Alonso Diego A. , Najera Carmen , Pacheco M. Carmen
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
Orthogonally Functionalized Oligomers for Controlled Self‐Assembly.
Authors: Flatt Austen K. , Yao Yuxing , Maya Francisco , Tour James M.
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
A Diels—Alder Approach for the Synthesis of Highly Functionalized Benzo‐annulated Indan‐Based α‐Amino Acid Derivatives via a Sultine Intermediate.
Authors: Kotha Sambasivarao , Ghosh Arun Kumar
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.
Synthesis of Perfluoro‐ and 2‐Trifluoromethylpentafluorodihydrofurans and Their Epoxy Derivatives.
Authors: Filyakova T. I. , Kodess M. I. , Zapevalov A. Ya. , Saloutin V. I.
Published: June 2004

For Abstract see ChemInform Abstract in Full Text.