RESUMO
The need for affordable systems that are capable of regulating the temperature of living or storage spaces has increased the interest in exploring phase change materials (PCMs) for latent heat thermal energy storage (LHTES). This study investigates n-nonadecane (C19H40) and n-eicosane (C20H42) as alkane hydrocarbons/paraffins for LHTES applications. An epoxy resin is used as the support matrix medium to mitigate paraffin leakage, and a thickening agent is utilized to suppress phase separation during the curing process. In order to enhance the thermal conductivity of the epoxy-paraffin composite, conductive agents including carbon nanofibers (CNFs), carbon nanotubes (CNTs), boron nitride (BN) microparticles, or boron nitride nanotubes (BNNTs) are incorporated in different gravimetric ratios. Enhancements in latent heat, thermal conductivity, and heat transfer are realized with the addition of the thermal fillers. The sample composition with 10 wt.% BN shows excellent reversibility upon extended heating-cooling cycles and adequate viscosity for template casting as well as direct three-dimensional (3D) printing on fabrics, demonstrating the feasibility for facile integration onto liners/containers for thermal regulation purposes.
Assuntos
Compostos de Boro/química , Carbono/química , Resinas Epóxi/química , Temperatura Alta , Nanocompostos/química , Nanocompostos/ultraestrutura , Análise Espectral , TermodinâmicaRESUMO
Research conducted during past decades to reduce the level of the tobacco specific nitrosamine N-nitrosonornicotine (NNN) and its precursor nornicotine in tobacco yielded identification of three tobacco genes encoding for cytochrome P450 nicotine demethylases converting nicotine to nornicotine. We carried out trials to investigate the effect of using tobaccos containing three non-functional nicotine demethylase genes on the selective reduction of NNN in cigarette tobacco filler and mainstream smoke. Our results indicate that the presence of non-functional alleles of the three genes reduces the level of nornicotine and NNN in Burley tobacco by 70% compared to the level observed in currently available low converter (LC) Burley tobacco varieties. The new technology, named ZYVERT™, does not require a regular screening process, while a yearly selection process is needed to produce LC Burley tobacco seeds for NNN reduction. The reduction of NNN observed in smoke of blended prototype cigarettes is proportional to the inclusion level of tobacco having ZYVERT™ technology. Inclusion of Burley tobacco possessing the new trait into a typical American blend resulted in a selective reduction of NNN in cigarette smoke, while the levels of other Harmful and Potentially Harmful Constituents (HPHC) currently in the abbreviated list provided by the US Food and Drug Administration are statistically equivalent in comparison with the levels obtained in reference prototype cigarettes containing LC Burley.
Assuntos
Sistema Enzimático do Citocromo P-450/genética , Nicotiana/química , Nicotiana/genética , Nicotina/metabolismo , Nitrosaminas/metabolismo , Fumaça/análise , Alelos , Nicotina/genética , Sementes/química , Produtos do Tabaco/análiseRESUMO
Hydrochloric acid (HCl) pollution from perchlorate based propellants is well known for both launch site contamination, as well as the possible ozone layer depletion effects. Past efforts in developing environmentally cleaner solid propellants by scavenging the chlorine ion have focused on replacing a portion of the chorine-containing oxidant (i.e., ammonium perchlorate) with an alkali metal nitrate. The alkali metal (e.g., Li or Na) in the nitrate reacts with the chlorine ion to form an alkali metal chloride (i.e., a salt instead of HCl). While this technique can potentially reduce HCl formation, it also results in reduced ideal specific impulse (ISP). Here, we show using thermochemical calculations that using aluminum-lithium (Al-Li) alloy can reduce HCl formation by more than 95% (with lithium contents ≥15 mass%) and increase the ideal ISP by â¼7s compared to neat aluminum (using 80/20 mass% Al-Li alloy). Two solid propellants were formulated using 80/20 Al-Li alloy or neat aluminum as fuel additives. The halide scavenging effect of Al-Li propellants was verified using wet bomb combustion experiments (75.5±4.8% reduction in pH, â [HCl], when compared to neat aluminum). Additionally, no measurable HCl evolution was detected using differential scanning calorimetry coupled with thermogravimetric analysis, mass spectrometry, and Fourier transform infrared absorption.
RESUMO
The evolution of the levels of tobacco-specific N-nitrosamines (TSNA), N-nitrosonornicotine (NNN) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in mainstream (MS) cigarette smoke is investigated based on smoke and tobacco chemistry data of cigarette brands sold by Philip Morris International (PMI) between 2000 and 2014. A total of 315 cigarette samples representing a wide range of product and design characteristics manufactured by PMI between 2008 and 2014 were analyzed and compared to a previously published dataset of PMI brands manufactured in 2000. The data indicate that there is a substantial reduction of NNN and NNK levels in tobacco fillers and MS cigarette smoke per mg of tar and per mg of nicotine using Health Canada Intense (HCI) machine-smoking regime. This observed reduction in NNN and NNK levels in MS cigarette smoke is also supported by the downward trend observed on NNN and NNK levels in USA flue-cured Virginia and Burley tobacco lots from 2000 to 2014 crops, reflecting effectiveness of measures taken on curing and agricultural practices designed to minimize TSNA formation in tobacco.
Assuntos
Nicotiana/química , Nitrosaminas/análise , Fumaça/análise , Produtos do Tabaco/análise , Poluição por Fumaça de Tabaco/análise , Agricultura , Comércio , Qualidade de Produtos para o Consumidor , Humanos , Nitrosaminas/efeitos adversos , Medição de Risco , Fumaça/efeitos adversos , Fumar/efeitos adversos , Fatores de Tempo , Nicotiana/efeitos adversos , Nicotiana/crescimento & desenvolvimento , Produtos do Tabaco/efeitos adversos , Poluição por Fumaça de Tabaco/efeitos adversosRESUMO
The colonization history of Madeiran house mice was investigated by analysing the complete mitochondrial (mt) D-loop sequences of 156 mice from the island of Madeira and mainland Portugal, extending on previous studies. The numbers of mtDNA haplotypes from Madeira and mainland Portugal were substantially increased (17 and 14 new haplotypes respectively), and phylogenetic analysis confirmed the previously reported link between the Madeiran archipelago and northern Europe. Sequence analysis revealed the presence of four mtDNA lineages in mainland Portugal, of which one was particularly common and widespread (termed the 'Portugal Main Clade'). There was no support for population bottlenecks during the formation of the six Robertsonian chromosome races on the island of Madeira, and D-loop sequence variation was not found to be structured according to karyotype. The colonization time of the Madeiran archipelago by Mus musculus domesticus was approached using two molecular dating methods (mismatch distribution and Bayesian skyline plot). Time estimates based on D-loop sequence variation at mainland sites (including previously published data from France and Turkey) were evaluated in the context of the zooarchaeological record of M. m. domesticus. A range of values for mutation rate (mu) and number of mouse generations per year was considered in these analyses because of the uncertainty surrounding these two parameters. The colonization of Portugal and Madeira by house mice is discussed in the context of the best-supported parameter values. In keeping with recent studies, our results suggest that mutation rate estimates based on interspecific divergence lead to gross overestimates concerning the timing of recent within-species events.
Assuntos
Evolução Molecular , Variação Genética , Camundongos/genética , Animais , Sequência de Bases , Cromossomos de Mamíferos/genética , DNA Mitocondrial/genética , Geografia , Haplótipos , Dados de Sequência Molecular , Filogenia , Portugal , Análise de Sequência de DNARESUMO
The purpose of this study was to determine aetiological agents of diarrhoea in neonatal calves and to investigate virulence gene markers of Escherichia coli strains isolated from calves by multiplex polymerase chain reaction (PCR). Eighty-two diarrhoeic calves and 18 healthy calves were used as subjects. Faeces were taken from the rectums of all the calves and were subjected to bacterial culture. Antigen enzyme-linked immunosorbent assay (ELISA) was performed to detect rotavirus, coronavirus and E. coli K99 in faeces of all the calves. A multiplex PCR was used to characterize E. coli strains in all the calves. Escherichia coli was isolated from 37 faeces samples, Enterococcus ssp. was isolated from 22 faeces samples and Salmonella was isolated from one faeces sample in diarrhoeic calves. Furthermore, only E. coli was isolated from all 18 faeces samples of healthy calves. Of the 37 E. coli isolated from diarrhoeic calves, K99 (18.9%), F41 (18.9%), heat-stable enterotoxin a (STa) (18.9%), Shiga toxin 1 (Stx1; 13.5%) and Shiga toxin 2 (Stx2; 5.4%) and intimin (8.1%) genes were identified by multiplex PCR. Of the 18 E. coli isolated from healthy calves, K99 (16.6%) and intimin (55.5%) genes were identified by PCR. A total of 15 rotavirus, 11 coronavirus and 11 E. coli K99 were detected in diarrhoeic calves by the antigen ELISA. As a result, this study shows that rotavirus, coronavirus, E. coli and Enterococcus ssp. were determined to play a role in the aetiology of diarrhoea in the neonatal calves. K99, F41, STa, Stx1 and Stx2 were found as the most common virulence gene markers of E. coli strains isolated from calves with diarrhoea. Multiplex PCR may be useful for characterization of E. coli isolated from calves.
Assuntos
Doenças dos Bovinos/microbiologia , Diarreia/veterinária , Infecções por Escherichia coli/veterinária , Escherichia coli/patogenicidade , Toxinas Shiga/biossíntese , Fatores de Virulência/genética , Animais , Animais Recém-Nascidos , Bovinos , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/virologia , Contagem de Colônia Microbiana/veterinária , Coronavirus/isolamento & purificação , Coronavirus/patogenicidade , Diarreia/etiologia , Farmacorresistência Bacteriana/genética , Escherichia coli/genética , Escherichia coli/metabolismo , Infecções por Escherichia coli/epidemiologia , Infecções por Escherichia coli/microbiologia , Fezes/microbiologia , Marcadores Genéticos/genética , Reação em Cadeia da Polimerase/métodos , Reação em Cadeia da Polimerase/veterinária , Rotavirus/isolamento & purificação , Rotavirus/patogenicidade , Toxinas Shiga/genética , Turquia/epidemiologiaRESUMO
The article reviews over 30 years' study of the chromosomal variation of the western house mice (Mus musculus domesticus) from the neighboring valleys of Poschiavo and Valtellina on the Swiss-Italian border. This is done in the context of the social and political history of this area, on the grounds that mice, as commensals, are influenced by human history. The chromosomal study of mice in this area was initiated because their unusual black coat color led a 19th century naturalist to describe the "tobacco mice" from Val Poschiavo as a separate species (Mus poschiavinus). The special coloration of the Val Poschiavo mice is matched by their chromosomes: they have 26 chromosomes instead of the usual 40. The Val Poschiavo mice are not a separate species according to the Biological Species Concept; instead they constitute a chromosome race (the "Poschiavo", POS) that is related to other races with reduced chromosome numbers that occur in N Italy (of which only those races in Val Poschiavo and Upper Valtellina have black coats). A phylogenetic analysis of mitochondrial DNA sequences suggests that the lineage of chromosome races found in N Italy was not formed during an extreme population bottleneck, although such bottlenecks have apparently occurred during the origin of individual races and certainly have influenced single populations. In one small, isolated population in Valtellina (Migiondo), two chromosome races (the POS and the "Upper Valtellina", UV, 2n = 24) became reproductively isolated from each other. In another small population (Sernio) bottlenecking led to fixation of a hybrid form with the UV karyotype and coat color, but with allozyme and microsatellite alleles characteristic of mice with the standard 40-chromosome karyotype. Two of the chromosome races in Valtellina (the UV and the "Mid Valtellina", MV, 2n = 24) also appear to be the product of hybridization. The dynamic history and patchy distribution of the house mouse chromosome races in Val Poschiavo and Valtellina in part reflects extinction-recolonization events; the formation of the UV and MV races and the introduction of the pale brown Standard race mice are believed to reflect such events. Dynamism in the chromosomal constitution of single populations is also evident from 25 years of data on the population in Migiondo. Due to change in agricultural practices, house mice in Valtellina and Val Poschiavo are becoming rarer, which is likely to have further impacts on the distribution and characteristics of the chromosome races in this area.
Assuntos
Hibridização Genética , Camundongos/genética , Animais , Cromossomos , Variação Genética , Cor de Cabelo/genética , Itália , Camundongos/classificação , SuíçaRESUMO
'Tousan 140' and 'Hourei', two soybean [Glycine max (L) Merr.] accessions from Japan, each possess a single gene at different loci for resistance to Japanese Soybean mosaic virus (SMV) strain SMV C. However, more genetic information is needed to utilize these lines in a breeding program. The objectives of this study were to determine (i) the reaction of Tousan 140 and Hourei to SMV-G1 through G7 strains, (ii) the inheritance of SMV resistance in Tousan 140 and Hourei to strains SMV-G1 and G7, and (iii) the allelomorphic relationship of resistance genes in these accessions with previously known resistance genes. Tousan 140 and Hourei were crossed with SMV susceptible cultivar Lee 68 to study the inheritance of resistance. They were also crossed with lines possessing Rsv1, Rsv3, and putative Rsv4, and to each other, to elucidate the allelomorphic relationships among the genes in Tousan 140, Hourei, and previously reported genes. Inheritance and allelism studies indicated that Tousan 140 possesses two SMV resistance genes. These two genes were separated in two F(2:3) lines. One of the genes, an allele of Rsv1, expresses resistance to SMV-G1 through G3 and susceptibility to SMV-G5 through G7 while the other one, an allele of Rsv3, expresses resistance to SMV-G5 through G7 and susceptibility to SMV-G1 through G3. Their presence in Tousan 140 makes it resistant to strains SMV-G1 through G7. Hourei also is resistant to SMV-G1 through G7 and possesses two SMV resistance genes, which are also alleles of Rsv1 and Rsv3. One, probably the Rsv1 allele, expresses resistance to SMV-G1 and G7 and the other, probably the Rsv3 allele, expresses resistance to SMV-G7, but is susceptible to G1.
RESUMO
Soybean mosaic virus (SMV) is a major viral pathogen, affecting soybean [Glycine max (L.) Merr.] production worldwide. The Rsv3 gene of soybean confers resistance to three of the most virulent strains (G5-G7) of SMV. The objectives of this study were to map Rsv3 and develop polymerase chain reaction (PCR) based markers for marker-assisted selection (MAS) purposes. Disease-response data were collected from two F(2) mapping populations, L29 (Rsv3) x Lee68 (rsv3) and Tousan 140 (Rsv3) x Lee68 (rsv3). Bulk segregant analysis based on amplified fragment length polymorphism (AFLP) markers demonstrated that the Rsv3 locus maps to the soybean molecular linkage group (MLG) B2 between restriction fragment length polymorphism (RFLP) markers A519 and Mng247. These two tightly linked RFLP markers were converted to PCR-based markers to expedite MAS. Sequence analysis of the Mng247 genomic region revealed similarity to the consensus sequence of a leucine-rich repeat (LRR) characteristic of the extracellular LRR class of disease resistance genes. Results from this study will be useful in pyramiding viral resistance genes and in cloning the Rsv3 gene.
RESUMO
To study the colonization history of the house mouse (Mus musculus domesticus) on the Madeiran archipelago, complete mitochondrial D-loop sequences were obtained for 44 individuals from Madeira, Porto Santo and Ilhas Desertas. Altogether, 19 D-loop haplotypes were identified which formed part of a single clade in a phylogeny incorporating haplotypes from elsewhere in the range of M. m. domesticus, indicating that the Madeiras were colonized from a single source. Similarities between the sequences found in the Madeiras and those in Scandinavia and northern Germany suggest that northern Europe was the source area, and there is the intriguing possibility that the Vikings may have accidentally brought house mice to the archipelago. However, there is no record of Vikings visiting the Madeiras; on historical grounds, Portugal is the most likely source area for Madeiran mice and further molecular data from Portugal are needed to rule out that possibility.
Assuntos
Evolução Molecular , Camundongos/genética , Animais , DNA Mitocondrial/genética , Europa (Continente) , Variação Genética , Haplótipos , Camundongos/classificação , Dados de Sequência Molecular , Filogenia , PortugalRESUMO
The gene symbol Rsv2 was previously assigned to the gene in the soybean [Glycine max (L.) Merr.] line OX670 for resistance to soybean mosaic virus (SMV). The Rsv2 gene was reported to be derived from the Raiden soybean (PI 360844) and to be independent of Rsv1. Accumulated data from our genetic experiments were in disagreement with this conclusion. In this study, Raiden and L88-8431, a Williams BC5 isoline with SMV resistance derived from Raiden, were crossed with two SMV-susceptible cultivars to investigate the mode of inheritance of SMV resistance in Raiden. They were also crossed with five resistant cultivars to examine the allelomorphic relationships of the Raiden gene with other reported genes at the Rsv1 locus. F1 plants, F2 populations, and F2-derived F3 (F2:3) lines were tested with SMV strains G1 or G7 in the greenhouse or in the field. The individual plant reactions were classified as resistant (R, symptomless), necrotic (N, systemic necrosis), or susceptible (S, mosaic). The F2 populations from R x S crosses segregated in a ratio of 3 (R + N):1 S and the F2:3 lines from Lee 68 (S) x Raiden (R) exhibited a segregation pattern of 1 (all R):2 segregating:1 (all S). The F2 populations and F2:3 progenies from all R x R crosses did not show any segregation for susceptibility. These results demonstrate that the resistance to SMV in Raiden and L88-8431 is controlled by a single dominant gene and the gene is allelic to Rsv1. The heterozygous plants from R x S and R x N crosses exhibited systemic necrosis when inoculated with SMV G7, indicating a partial dominance nature of the resistance gene. Raiden and L88-8431 are both resistant to SMV G1-G4 and G7, but necrotic to G5, G6, and G7A. Since the resistance gene in Raiden is clearly an allele at the Rsv1 locus and it exhibits a unique reaction to the SMV strain groups, assignment of a new gene symbol, Rsv1-r, to replace Rsv2 would seem appropriate. Further research is ongoing to investigate the possible existence of the Rsv2 locus in OX670 and its relatives.
Assuntos
Cruzamentos Genéticos , Ligação Genética , Glycine max/genética , Vírus do Mosaico/fisiologia , Doenças das Plantas/genética , Frequência do Gene , Genótipo , Doenças das Plantas/virologia , Glycine max/virologiaRESUMO
These studies centre on the 'Barcelona' karyotypic race of the western house mouse (Mus musculus domesticus), first described by Adolph & Klein (1981). This is one of many races within M. m. domesticus characterized by metacentric chromosomes that have originated by repeated Robertsonian fusions, with perhaps further modification by whole-arm reciprocal translocations. Data on 111 mice from 20 sites show that the race is centred 24 km to the west of Barcelona city and has a homozygous metacentric karyotype of 2n = 28 (3.8, 4.14, 5.15, 6.10, 9.11, 12.13). The race has a small range, and mice with the standard 40-acrocentric karyotype were caught only 30 km from the race centre. Throughout the area of occurrence of metacentrics there is polymorphism (i.e. presence of acrocentrics in the population), although all six metacentrics approach fixation close to the race centre. Thus, there is a hybrid zone between the Barcelona and standard races. The centres and widths of all clines (except 3.8) were determined. Likelihood ratio tests showed that most of the cline centres differed significantly in position (i.e. the clines were staggered) and the clines for metacentrics 6.10 and 9.11 were significantly narrower than those for 4.14, 5.15 and 12.13. Overall, the clines tended to be wider the further they were from the race centre. There are various possible explanations for this hybrid zone structure and further data are needed to distinguish between them.
Assuntos
Cromossomos/ultraestrutura , Camundongos/genética , Animais , Variação Genética , Genética Populacional , Cariotipagem , Funções Verossimilhança , Masculino , Camundongos/classificação , Polimorfismo Genético , Espanha , Especificidade da Espécie , Translocação GenéticaRESUMO
Complete D-loop sequences of 20 Mus from three localities in Turkey and seven in Iran were characterized. These countries are thought to be close to the place of origin of the subspecies Mus musculus domesticus. Five new M. m. domesticus haplotypes were added to the nine already known for the region. Four of these 14 haplotypes were very similar to the consensus D-loop sequence for western Europe defined by Nachman et al. (1994), which may represent the ancestral condition for M. m. domesticus. A divergent mtDNA lineage is found in various parts of Turkey and northern Iran; it has spread into western Europe, but other European lineages were not found in either Turkey or Iran. The other Mus D-loop sequences were of M. m. castaneus and Mus macedonicus and confirmed M. macedonicus as a monotypic species with low nucleotide diversity. The prevalence of the standard 40-chromosome complement in this region is particularly interesting with regards M. m. domesticus, as it is consistent with the in situ origin of Robertsonian karyotypic races (2n < 40) in western Europe.