Search

ABSTRACTSaksenaeais a monotypic genus belonging to the order Mucoralesand capable of producing severe human infections. Through a polyphasic study based on analysis of the sequences of the internal transcribed spacer (ITS) region, domains D1 and D2 of the 28S rRNA gene, and the elongation factor 1a (EF-1a) gene, as well as by evaluation of relevant morphological and physiological characteristics of a set of clinical and environmental strains, we have demonstrated that Saksenaea vasiformisis a complex of species. We propose as new species Saksenaea oblongispora, characterized by oblong sporangiospores and unable to grow at 42°C, and Saksenaea erythrospora, characterized by large sporangiophores and sporangia and by ellipsoid sporangiospores, biconcave in the lateral view. Itraconazole, posaconazole, and terbinafine were active against all isolates included in the study, while amphotericin B, voriconazole, and the echinocandins showed low activity.

Islet transplantation is an experimental therapy for selected patients with type 1 diabetes (T1DM). It remains limited by immunosuppressive drug toxicity, progressive loss of insulin independence, allosensitization and the need for multiple islet donors. We describe our experience with an efalizumab‐based immunosuppressive regimen as compared to the prevailing standard regimen, the Edmonton protocol. Twelve patients with T1DM received islet transplants: eight were treated with the Edmonton protocol; four were treated with daclizumab induction, a 6‐month course of tacrolimus, and maintenance with efalizumab and mycophenolate mofetil. The primary endpoint was insulin independence after one islet infusion. Only two Edmonton protocol treated patients achieved the primary endpoint; six required islets from multiple donors, and all experienced leukopenia, mouth ulcers, anemia, diarrhea and hypertransaminasemia. Four became allosensitized. All patients treated with the efalizumab‐based regimen achieved insulin independence with normal hemoglobin A1c after a single islet cell infusion and remained insulin independent while on efalizumab. These patients experienced significantly fewer side effects and none became allosensitized. Trial continuation was terminated by withdrawal of efalizumab from the market. These data suggest that this efalizumab‐based regimen prevents islet rejection, is well tolerated, and allows for single donor islet transplantation.

Sporothrix inflatais a saprobic member of the Ophiostoma stenoceras-Sporothrix schenckiispecies complex, reported mainly from soil. Ophiostoma bragantinum, an ascomycete described from Brazil, has been proposed as its possible teleomorph. Previous studies revealed that Sporothrix inflatais phenotypically and genetically variable, suggesting the existence of cryptic species. During a continued survey on the biodiversity of microfungi from different countries, seven isolates morphologically similar to S. inflatawere obtained from soil samples collected in Spain and USA. In this study their phenotypic features and phylogenetic relationships were assessed. DNA sequence data of two nuclear loci revealed that these isolates correspond to two unnamed clades in S. inflatas.l., one of which also included the type strain of Humicola dimorphospora, a species that traditionally has been considered a synonym of S. inflata. These two groups are proposed herein as Sporothrix brunneoviolaceasp. nov. and Sporothrix dimorphosporacomb. nov. S. brunneoviolaceais characterized phenotypically by the production of a diffusible violet-brown pigment in culture and mostly globose, pigmented, lateral blastoconidia. On the other hand S. dimorphosporalacks diffusible pigments and shows mostly subglobose to obovoid pigmented lateral blastoconidia. In contrast to the type strain of S. inflata S. brunneoviolaceaand S. dimorphosporaassimilate raffinose. The phylogenetic analysis suggested that the proposed anamorph-teleomorph connection between S. inflataand O. bragantinummight not be correct.

In a study on soil microfungi from different countries two new hyphomycetes were found. The first one, Ramophialophora humicola, isolated from a soil sample collected in Ronda (Spain), is characterized by producing profusely branched conidiophores ending in sterile, sometimes swollen apices, and subhyaline, dacryoid conidia borne from both integrated and discrete phialides with conspicuous collaretes. ITS sequence data reveal its relationships with members of the Sordariales and its genetic differences with other fungi morphologically close, such as Cladorrhinumspp. The second species, Fibulochlamys chilensis, isolated from a soil sample collected in La Junta (Chile), is characterized by micronematous, clamped, mostly branched conidiophores producing thallic, one-celled, thick-walled conidia that exhibit strongly wrinkled surfaces in age. The analysis of partial sequences of the ITS region and 28S rRNA gene reveal that this fungus is close to members of the gilled Agaricales.

ABSTRACTSeveral members of the order Mucorales(subphylum Mucoromycotina) are important agents of severe human infections. The identification of these fungi by using standard mycologic methods is often difficult and time consuming. Frequently, the etiological agent in clinical cases is reported either as a Mucorsp., which is not the most frequent genus of zygomycetes, or only as a member of the Mucorales. For this reason, the actual spectrum of species of zygomycetes and their incidences in the clinical setting is not well known. The goals of this study were to compare the results of the molecular identification of an important set of clinical isolates, received in a mycological reference center from different regions of the United States, with those obtained by using the traditional morphological methods and to determine the spectrum of species involved. We tested 190 isolates morphologically identified as zygomycetes by using sequencing of the internal transcribed spacer (ITS) region of the ribosomal DNA. Molecular identification revealed that Rhizopus oryzaerepresented approximately half (44.7%) of these isolates. The remainder was identified as Rhizopus microsporus(22.1%), Mucor circinelloides(9.5%), Mycocladus corymbifer(formerly Absidia corymbifera) (5.3%), Rhizomucor pusillus(3.7%), Cunninghamella bertholletiae(3.2%), Mucor indicus(2.6%), Cunninghamella echinulata(1%), and Apophysomyces elegans(0.5%). The most common anatomic sites for clinically significant zygomycetes, as determined by isolates sent to the Fungus Testing Laboratory for identification and/or susceptibility testing and included in this study, were the sinuses, lungs, and various cutaneous locations, at 25.8%, 26.8%, and 28%, respectively. These sites represented approximately 80% of the isolates evaluated. A high level of correlation (92.6%) between morphological and molecular identifications was found.

ABSTRACTIsolation and characterization of the new species Chrysosporium ophiodiicolafrom a mycotic granuloma of a black rat snake (Elaphe obsoleta obsoleta) are reported. Analysis of the sequences of different fragments of the ribosomal genes demonstrated that this species belongs to the Onygenales and that this species is genetically different from other morphologically similar species of Chrysosporium. This new species is unique in having both narrow and cylindrical-to-slightly clavate conidia and a strong, pungent odor.

ABSTRACTThe in vitro activity of amphotericin B in combination with micafungin was evaluated against 115 isolates representing seven species of Candida. Overall, the percentages of synergistic interactions were 50% and 20% when the MIC-2 (lowest drug concentration to cause a prominent reduction in growth) and MIC-0 (lowest drug concentration to cause 100% growth inhibition) end point criteria, respectively, were used. Antagonism was not observed. Some of the interactions were confirmed by time-kill assays.

Recent advances in human allogeneic islet transplantation have established ?-cell replacement therapy as a potentially viable treatment option for individuals afflicted with Type 1 diabetes. Two recent successes, one involving neonatal porcine islet xenografts transplanted into diabetic rhesus macaques treated with a costimulation blockade-based regimen and the other involving diabetic cynomolgus monkeys transplanted with adult porcine islet xenografts treated with an alternative multidrug immunosuppressive regimen have demonstrated the feasibility of porcine islet xenotransplantation in nonhuman primate models. In the current study, we assessed whether transplantation of adult porcine islet xenografts into pancreatectomized macaques, under the cover of a costimulation blockade-based immunosuppressive regimen (CD28 and CD154 blockade), could correct hyperglycemia. Our findings suggest that the adult porcine islets transplanted into rhesus macaques receiving a costimulation blockade-based regimen are not uniformly subject to hyperacute rejection, can engraft (25 recipients), and have the potential to provide sustained normoglycemia. These results provide further evidence to suggest that porcine islet xenotransplantation may be an attainable strategy to alleviate the islet supply crisis that is one of the principal obstacles to large-scale application of islet replacement therapy in the treatment of Type 1 diabetes.

Purpose To compare the safety and efficacy of a new enhanced viscosity ophthalmic formulation of tobramycin, given twice daily (BID), with the existing four times daily (QID) treatment regimen in patients with acute bacterial conjunctivitis.Methods This was a 12-day, multicenter, observer-masked, randomized, parallel group study. Patients received one drop of tobramycin 0.3% (3 mg/mL) enhanced viscosity ophthalmic solution BID or tobramycin 0.3% (3 mg/mL) ophthalmic solution QID in the affected eyes for 7 days. The primary efficacy variable was the percentage of patients with sustained cure/presumed bacterial eradication based on clinical judgment at the test-of-cure visit (Day 12). Pretherapy bacterial isolates were obtained and tested for susceptibility to tobramycin by determination of minimum inhibitory concentrations (MIC).Results A total of 276 patients were enrolled in the study and 203 of these were culture positive and attended all follow-up examinations. In this group, 98% of those treated with tobramycin enhanced viscosity ophthalmic solution and 99% of those treated with tobramycin 0.3% ophthalmic solution were categorized as having sustained cure/presumed eradication at the test-of-cure visit (p=0.6037). Reported adverse events were not serious, mild to moderate in severity, and generally did not prevent continuation in the study. Several pretreatment pathogens demonstrated tobramycin resistance (MIC > 4 mg/mL). However, therapy with both treatments was effective in the majority of the cases.Conclusions Tobramycin enhanced viscosity ophthalmic solution is well tolerated and has equivalent efficacy to the established treatment regimen with a simplified posology. The formulation provides an alternative therapy for acute bacterial conjunctivitis that should improve patient compliance and satisfaction.

The synthesis of the methyl complexes [M{η⁵-C5H3-1,3-(SiMe2-η-NtBu)2}Me] (M = Ti, Zr) and the results of the insertion reactions into their metal−methyl bonds have been investigated and compared with the similar reactions previously reported for related metal−amido [M{η⁵-C5H3-1,3-(SiMe2-η-NtBu)2}(NMe2)] (M = Ti, Zr) and metal−benzyl [M{η⁵-C5H3-1,3-(SiMe2-η-NtBu)2}(CH2Ph)] (M = Ti, Zr) compounds. The structural characterization of the resulting η²-iminocarbamoyl [Zr{η⁵-C5H3-1,3-(SiMe2-η-NtBu)2}{η²-C(NMe2)&dbd;N(2,6-Me2C6H3)}], η²-iminoacyl [M{η⁵-C5H3-1,3-(SiMe2-η-NtBu)2}(η²-CR‘&dbd;NR)] (M = Zr, R = 2,6-Me2C6H3, R‘ = CH2Ph, Me; M = Zr, R = tBu, R‘ = Me; M = Ti, R = 2,6-Me2C6H3, R‘ = Me), and alkoxo [Zr{η⁵-C5H3-1,3-(SiMe2-η-NtBu)2}{OC(CH2Ph)Ph2}] complexes and of the asymmetrical bicyclic enediamido compound [Ti(η⁵-C5H3-1,3-{(SiMe2-η-NtBu)(SiMe2-NtBu-C(η-NR)&dbd;C(Me)(η-NR)}] (R = 2,6-Me2C6H3), formed by coupling iminoacyl and iminocarbamoyl ligands, is also described. The molecular structures of the zirconium complexes [Zr{η⁵-C5H3-1,3-(SiMe2-η-NtBu)2}Me] and [Zr{η⁵-C5H3-1,3-(SiMe2-η-NtBu)2}{η²-C(CH2Ph)&dbd;N(2,6-Me2C6H3)}]and the titanium derivative [Ti(η⁵-C5H3-1,3-{(SiMe2-η-NtBu)(SiMe2-NtBu-C(η-NR)&dbd;C(Me)(η-NR)}] (R = 2,6-Me2C6H3) have been determined by X-ray diffraction studies.

The effect of a sodium ionomer (ion.Na+) on the compatibility of polypropylene (PP)/high‐barrier ethylene–vinyl alcohol copolymer (EVOH) blends was studied in terms of the thermal, mechanical, and optical properties and morphology. The rheological behavior, tensile tests, and morphology of the binary blends showed that the miscibility of EVOH with PP was very poor. The miscibility of the polymers improved with the ionomer addition. In general, the ion.Na+ concentration did not alter the thermal behavior of the blends, but it did improve the ductility of the injection‐molded specimens. Scanning electron micrographs displayed better adhesion between the PP and EVOH phases in the samples with the ionomer. The mechanical improvement was better in the film samples than in the injection‐molded samples. A 90/10 (w/w) PP/EVOH film with 5% ion.Na+ and an 80/20 (w/w) PP/EVOH film with 10% ion.Na+ presented better global properties than the other blends studied. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1763–1770, 2004

The properties of two polyethylenes [a high-density polyethylene (HDPE) and a low-density polyethylene (LDPE)] were studied after several extrusion cycles. To reduce the degradation effects during the reprocessing, a mixture of two stabilizers was added to the formulations. The predominant degradation mechanism was chain scission for the HDPE and chain branching and crosslinking for the LDPE. For both polyethylenes the FTIR spectra exhibited a growth in the number of carbonyl groups as a function of the number of extrusion cycles. Their tensile properties were degraded with the reprocessing but both polyethylenes maintained their nearly constant thermal behavior and crystallinity. The addition of a primary phenolic antioxidant and a secondary phosphite antioxidant preserved the melt behavior of virgin materials after the reprocessing and reduced the degradation effects. From the tensile tests, the efficiency of the antioxidants in the LDPE was very high and, after the reprocessing, the material retained the mechanical properties of virgin LDPE. The efficiency of the antioxidants for the HDPE was not significant. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3910–3916, 2004

With the aim of selecting a precursor of a polyhedral oligomeric silsesquioxane (POSS) reacted with aromatic diamines for its incorporation into an epoxy network, to generate an organic–inorganic hybrid material containing POSS, a polyhedral oligomeric silsesquioxane (glycidylisobutyl–POSS) was reacted with the diamines 4,4'-methylenebis(2,6-diethylaniline) (MDEA), 4,4'-diaminediphenylmethane (DDM), and 4,4'-(1,3-phenylenediisopropylidene)bisaniline (BSA), at 160°C and different times, in a proportion rich in amines. The distribution of species in the reaction was followed by gel permeation chromatography (GPC). From the experimental data obtained the selected precursor was POSS/BSA reacted at 160°C for 20 or 30 min, to ensure that all the POSS was reacted, that there was a maximum of the monosubstituted amines, and that there was no degradation. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1576–1583, 2004

The mechanical properties of an epoxy system containing a diglycidyl ether of bisphenol A and 1,3-bis(aminomethylcyclohexane) modified with different amounts of poly(acrylonitrile-co-butadiene-co-styrene) (ABS) were studied. Properties examined include tensile stress, percentage strain, tensile modulus, and tensile toughness determined in tensile tests, Rockwell hardness, and energy and maximum force to break a specimen in Charpy impact tests. The effect of the modification produced with the ABS was also studied using statistical methods including analysis of variance and multiple comparisons. The obtained data showed a significant effect of the modification produced with the ABS on the mechanical properties of this epoxy system, especially with the amount of 5 ABS per hundred parts of resin on the tensile properties and on the hardness. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 461–467, 2004

In this work an epoxy system containing a diglycidyl ether of bisphenol A (DGEBA) and 1,3‐bis(aminomethyl)cyclohexane (1,3‐BAC) is modified with poly(acrylonitrile‐co‐butadiene‐co‐styrene) (ABS). Using dynamic mechanical analysis the glass transition temperatures and the associated activation energies are determined in the neat epoxy and some blends. The presence of ABS produces a constant diminution of the glass transition temperatures and increases the activation energies. The brittle character of the neat epoxy and the blends, compared with the ductile character of ABS, is studied using an instrumented impact pendulum. The shape of force–time curves and energies and data dispersion of each composition are analyzed. By using scanning electron microscopy it is possible to see various zones of different roughness and to distinguish the regions of tension and compression of Charpy impact fractured surfaces. The presence of a two phase‐morphology in the epoxy‐ABS blends is also shown.© 2002 Society of Chemical Industry

A new method for evaluating the thermal properties of the films and detecting fabrication failures has been provided. Moreover, this article studies the characterization of biaxially oriented polypropylene films (BOPP) using the Microthermal Analizer (μTA 2990). This instrument combines high-resolution imaging capabilities of the atomic force microscopy (AFM) with physical characterization by thermal analysis. In the first part of the work, topographic images of the film surfaces were obtained by AFM. They showed that the fabrication process and additives to the films caused differences in the sample topography. In the second part, the thermal conductivity images of multilayer films were obtained by thermal analysis mode. The thickness of each layer was determined for several BOPP films, based on the thermal conductivity signal registered by μTA 2990. Finally, it has been proven that this new technique is valid for detection of thermal transitions in polymer samples. Thus, melting points and glass transitions were measured in the samples with thermal probe. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1553–1561, 2002.

The phase-separation behavior and morphologies of a commercial epoxy resin based on diglycidyl ether of bisphenol A cured with the diamine hardener 1,3-bisaminomethylcyclohexane and blended with different amounts of acrylonitrile–butadiene–styrene thermoplastic were studied with dynamic mechanical analysis and other techniques. In comparison with the neat system, the modified systems reached before gelation and vitrification, events that were assigned to the onset and endset of the storage modulus signals in a dynamic mechanical analysis curve (storage modulus versus time). These results were explained by a phase-separation phenomenon induced by polymerization. Scanning electron microscopy and light transmission focused on phase separation revealed a sea-island morphology for low thermoplastic contents, a bicontinuous structure for intermediate thermoplastic contents, and an epoxy-nodular phase-inverted structure for high thermoplastic contents. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1277–1286, 2002

Behavioral genetic work in humans indicates that clinical hyperactivity is best viewed as the extreme end of activity levels in the population. However, current animal models of hyperactivity are not studied as quantitative traits as they are either knockout models or inbred strains. Furthermore, these animal models generally demonstrate elevated locomotion in novel environments, but not in their home‐cages. This is the opposite of the symptoms seen in the human condition where childhood hyperactivity is generally more pronounced in constant, unstimulating situations. In this study we filmed an outbred population of 44 heterogeneous stock (HS) mice under red light during their active phase, to assess the reliability of individual differences in home‐cage behavior and extract an index of home‐cage activity (HCA) level. We then compared this measure to locomotor behavior in a novel environment — the open‐field. Reliable individual differences in home‐cage behaviors such as running, swinging on bars, and burrowing were found, and principal component factor analysis yielded a general activity factor, which accounted for 32% of the variance and correlated 0.90 with a subjective impression of activity level. The correlation between HCA and locomotor activity in the open‐field was 0.23, which was non‐significant. However, the association with HCA level appeared to increase over the five minutes of the open‐field, presumably as the mice habituated. Furthermore, although mice displaying particularly high and low HCA were indistinguishable early in the open‐field task, they became significantly differentiated over time. We conclude that home‐cage behaviors and the open‐field, after habituation, display good face and construct validity, and may provide a good model of baseline activity for quantitative trait loci (QTL) discovery and functional genomics in the HS mice.

The heterogeneous stock (HS) is a genetically outbred line of mice established more than 30 years ago from an 8‐way cross of C57BL/6, BALB/c, RIII, AKR, DBA/2, I, A/J and C3H inbred mouse strains. The present study compared the performance of 40 HS mice across a battery of diverse cognitive tasks under a variety of motivations. Indices of emotionality were also included in order to assess their influence on performance. All measures of ability loaded positively on an unrotated first principal component that accounted for 31% of the variance, suggesting the presence of a common factor of general cognitive ability (g) underlying all tasks. A first factor derived from anxiety indices correlated nonsignificantly with all cognitive tasks and nonsignificantly with this gfactor, supporting the hypothesis that the factor is cognitive rather than temperamental in nature. The factor was also robust in relation to outliers and sex differences, accounting for 28% of the variance after removal of outlier individuals and also after correcting for variance owing to sex differences. A general cognitive ability (g) appears to underlie the performance of HS mice on a battery tapping diverse cognitive demands.

Four mutants, demonstrating a range of dormancy, were derived from the malting barley cv. Triumph. Although there were environmental effects on the rate of recovery from dormancy, relative performance of the genotypes was consistent. Recovery from water sensitivity was slower than recovery from dormancy for all genotypes, but a similar ranking of genotypes was observed with two mutants germinating more readily than the parental genotype. Exposure of the grain to the plant hormone abscisic acid (ABA) at the end of each wet phase during steeping had a highly significant effect on the malting performance of all samples. However, reduction in extract levels was significantly less in the two mutants that demonstrated more rapid recovery from dormancy. None of the mutants exceeded Triumph for hot water extract level after malting in two seasons at sites in Dundee (eastern Scotland) and Lleida (northeastern Spain). However, one mutant combined rapid recovery from dormancy with high extract levels when grown and malted under Scottish conditions and subjected to unithermal hot water extraction.

Using a microthermal analyzer TA Instruments 2990 μTA, we have analyzed the morphologies developed for the resin tetraglycidyl-4,4'-diaminodiphenylmethane cured with an aromatic amine 4,4'-diaminodiphenylsulphone modified with different amounts of poly(styrene-co-acrylonitrile) (SAN) thermoplastic. The phase-separation phenomenon induced by polymerization was also followed by scanning electron microscopy. Using the modulated local thermal-analysis mode of μTA, the glass-transition temperatures of different domains for each sample were evaluated. Dynamic mechanical analyzer experiments were made to evaluate the macroscopic thermal properties of the blends. A morphology was well established for all blends examined with these techniques showing a nodular structure, the epoxy-rich phase, and a continuous phase, the SAN-rich phase, that forms the matrix. From both microscopic and macroscopic thermal analyses, it is concluded that a phase separation exists for the blends investigated. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 40: 284–289, 2002

Times to gelation (tgel) and times to vitrification (tvit) during isothermal curing for the epoxy systems diglycidyl ether of bisphenol A (DGEBA)/1,3-bisaminomethylcyclohexane (1,3-BAC), tetraglycidyl-4,4'-diaminodiphenylmethane (TGDDM)/4-4'-diaminodiphenylsulfone (DDS), and TGDDM/epoxy novolac (EPN)/DDS were measured at different curing temperatures. This article reports on a method to determine tgel and tvit by dynamic mechanical analysis (DMA). Gelation was determined at the onset of the storage modulus or by the peak of the loss factor. Vitrification was defined as the curve of the storage modulus as the curve reached a constant level (endset) in DMA tests. The experimental values obtained for tgel and tvit were compared with values obtained by other experimental methods and with theoretical values (tgel's) or indirect determinations (tvit's). From kinetic analysis by differential scanning calorimetry, conversions corresponding to gelation were obtained for the three systems; this yielded a constant value for each system that was higher than theoretical value. Values of the apparent activation energies of the DGEBA/1,3-BAC, TGDDM/DDS, and TGDDM/EPN/DDS epoxy systems were obtained from plots of tgel's against reciprocal temperatures. They were 53.2, 58.2, and 46.5 kJ/mol, respectively. © 2002 John Wiley & Sons, Inc. J Appl Polym Sci 83: 78–85, 2002

Seven thousand years of barley cultivation under the environmental hardships typical of the Mediterranean climate have generated genetic singularity of the Spanish barleys, consistently reported in the literature. From the Spanish National Collection of 2289 accessions, a core subset with 159 landraces and 16 old varieties was constituted. Twenty-seven characters were evaluated for the core collection, to define the structure of the diversity. Several evaluation trials were carried out in 1999—2000, whereas yield trials were performed in earlier years. Phenotypic diversity was large for most of the characters studied. Comparisons of genetic diversity between the core and the original collections suggested that the core is a good representation of the existing diversity in the BNG. Comparisons with results of studies on Spanish materials from other collections seem to indicate that the Spanish diversity is not well represented in some world collections. Principal component analyses for quantitative and qualitative characters revealed a clear distinction between two- and six-row cultivars, and also between landraces and commercial varieties. Geographical origins of the landraces were correlated with grain yield, heading date, duration of grain filling period, and growth class. In relation to diseases, altitude played an important role on the resistance to powdery mildew and brown rust. For brown rust, all the resistant landraces came from low altitudes. These geographical gradients seemed consistent with prior knowledge about barley adaptation, and would confirm the agreement between passport data and true adaptive origin of these landraces from a geographical point of view.

The Newton polygon construction for ODEs, and Malgrange–Ramis polygon for partial differential equations in one variable are generalized in order to give an algorithm to find solutions of a linear partial differential equation at a singularity. The solutions found involve exponentials, logarithms and Laurent power series with exponents contained in a strongly convex cone.

The role of the brain-derived neurotrophic factor (BDNF), the BDNF receptor (TrkB), and the glutamic acid decarboxylase (GAD67) after neonatal, bilateral nerve deafferentiation during postnatal development was investigated in the rat superior colliculus (SC). BDNF and GAD67mRNA expression were significantly increased in optic (Op) and intermediate gray (InG) layers at 5, 8, 15, and 21 days after birth, but not in adult animals. However, TrkB mRNA expression was not modified at any time tested. At 15 days, where changes in BDNF and GAD67mRNAs were more evident, an upregulation of the NMDAR1AmRNA glutamate receptor in the Op and InG, a modification in the pattern of synaptic zinc in the superficial layers of SC, and an increased synaptophysin immunoreactivity in the Op was found. This indicates the existence of a synergic mechanism between BDNF and NMDA to determine refinement of connections after the loss of visual input in SC.

The characteristics of sorption and diffusion of water in an amine-cured epoxy system based on tetraglycidyl diaminodiphenylmethane and a novolac glycidyl ether resin were studied as a function both of the polymer microstructure, known from previous works, and the temperature. Water-sorption experiments and dynamic mechanical analysis (DMA) were performed. Tensile stress–strain and Rockwell hardness tests were conducted to investigate the effects of absorbed water on the mechanical properties of the material. Competing effects of the sorption of water in the free volume and of strong interactions between water molecules and polar groups of the network were used to explain the diffusional behavior observed, which followed Fick's second law. DMA analysis seemed to be sensitive to the water effects and the viscoelastic behavior was related both to the water-sorption processes and to the microstructure of the system. An important impact of water uptake on the tensile properties at break was also appreciated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 71–80, 2001

The malting barley cultivar, Triumph, and two mutants derived from it with higher (TL9) and lower (TL43) dormancy, respectively, were grown in replicated trials at Lleida, Spain and Dundee, Scotland, in 1999. Measurement ofbeta -amylase in the mature grain showed both mutants to have higher enzyme activity than the parental type with Spanish-grown samples higher in beta -amylase than Scottish-grown. There were no genotypic differences in beta -amylase thermostability or in the portion of the enzyme that was water-soluble. However, for all three genotypes, Scottish-grown samples had a higher proportion of water-soluble beta -amylase and total beta -amylase thermostability was also higher in the Scottish-grown samples. Data from the Spanish-grown samples suggested that water-soluble beta -amylase was slightly more thermostable than the portion of the enzyme released by papain.

The cure kinetics and the miscibility have been studied in blends of poly(styrene-co-acrylonitrile) (SAN) with tetraglycidyl-4,4′-diaminodiphenylmethane (TGDDM) and 4-4′-diaminodiphenylsulphone (DDS) as hardener. Differential scanning calorimetry (DSC) was the technique used for dynamic and isothermal experiments. Binary mixtures of SAN with the epoxy resin show complete miscibility over the whole composition range, displaying a single glass transition temperature. Kinetic analysis were performed using three kinetic models: Kissinger, Flynn–Wall–Ozawa and the phenomenological model developed by Kamal. Activation energies and kinetic parameters were determined by fitting experimental data. Diffusion control is incorporated to describe the cure in the latter stages, predicting the cure kinetics over the whole range of conversion. The autocatalytic mechanism was observed for the neat system and the epoxy-SAN blends. The reaction rates for the epoxy blends were found to be lower than of the neat epoxy. The reaction rates and the maximum conversions decreased when SAN contents increase, due to reduction of mobility of the reacting species.