Validation of a closing procedure for fourth-order RANS turbulence models with DNS data in an incompressible zero-pressure-gradient turbulent boundary layer.

Among factors affecting the accuracy of flow simulations with Reynolds-Averaged Navier-Stokes turbulence models is modeling turbulent diffusion processes. With the use of the Gram-Charlier series expansions, the turbulent diffusion in fourth-order one-point statistical closures of the Reynolds-Averaged Navier-Stokes equations can be modeled without introducing unknown model coefficients and without assuming turbulence being Gaussian. Terms representing turbulent diffusion processes in transport equations for second- and third-order velocity correlations do not require any modeling in such closures. In this regard, fourth-order closures are a more accurate alternative to lower-order closures where turbulent diffusion is modeled on semi-empirical or Gaussian turbulence assumptions. In the current paper, the accuracy of the closing procedure based on the Gram-Charlier series expansions is evaluated using data of direct numerical simulations in an incompressible zero-pressure-gradient turbulent boundary layer over a flat plate. One-point third-, fourth-, and fifth-order velocity moments were extracted for this purpose from the dataset collected by the Fluid Dynamics Group at the Universidad Politécnica de Madrid at two streamwise locations Reθ= 4101 and 5200 that correspond to channels and pipes at δ+= 1331 and 1626. Results demonstrate that the truncated Gram-Charlier series expansions are an accurate approximation of the fifth-order velocity moments in the considered flow.

Prepubertal children with suitable fitness and physical activity present reduced risk of oxidative stress.

To assess the impact of fitness status and physical activity on oxidative stress in prepubertal children, we measured selected biomarkers such as protein carbonyls (PC), lipid peroxidation products, and total nitrites, as well as the antioxidant system: total glutathione (TG), oxidized glutathione (GSSG), reduced glutathione (GSH), superoxide dismutase activity, and glutathione peroxidase. A total of 132 healthy children ages 7-12, at prepubertal stage, were classified into two groups according to their fitness level: low fitness (LF) and high fitness (HF). They were observed while engaged in an after-school exercise program, and a questionnaire was created to obtain information on their physical activity or sedentary habits. Plasma and red blood cells were obtained to analyze biomarkers. Regarding oxidative stress markers, the LF group and the sedentary group showed higher levels of TG and GSSG and a lower GSH/GSSG ratio than the HF group and the children engaged in physical activity. A negative association was found between PC and GSSG and TG and between TG and the GSH/GSSG ratio. Moreover, a negative correlation was found between GSSG and fitness, with a positive correlation with the GSH/GSSG ratio. TG, GSSG, and the GSH/GSSG ratio seem to be reliable markers of oxidative stress in healthy prepubertal children with low fitness or sedentary habits. This research contributes to the recognition that an adequate level of fitness and recreational physical activity in childhood leads to better health and oxidative status.

Cardiorespiratory fitness and oxidative stress: effect of acute maximal aerobic exercise in children and adolescents.

AIM: Evaluate the effects of oxidative stress in saliva in young males, according to their cardiorespiratory fitness and taking acute maximal aerobic exercise into consideration. An incremental exercise test (20 meter shuttle run) was used. METHODS: Seventy healthy male subjects, aged 10 to 14 years, were included in the study and were classified into two groups according to fitness parameters. Subjects were expected to take the 20 meter shuttle run test. RESULTS: Group I had high cardiorespiratory fitness while group II had low cardiorespiratory fitness below the mean for their age. Saliva samples were taken before and immediately after exercise in order to measure levels of reduced glutathione, lipoperoxides, glutathione/lipoperoxides ratio and catalase. The values of reduced glutathione were significantly diminished regardless the subjects' cardiorespiratory fitness. The glutathione/lipoperoxides ratio was significantly diminished in group I. In addition, positive correlations were observed between lipoperoxides values after the 20 meter shuttle run test. CONCLUSION: High cardiorespiratory fitness does not seem to be an essential factor effecting in the oxidative stress values before exercise. However, oxidative stress could be greater with more intensity and duration after and acute maximal physical exercise.

[Changes in oxidative stress biomarkers induced by puberty]. / Cambios en biomarcadores del estrés oxidativo inducidos por la pubertad.

AIM: Evaluate the influence of puberty in oxidative stress. SUBJECTS AND METHODS: The study included 38 prepubescent males with Tanner G(1)-P(1) and 32 healthy pubescent boys with Tanner G(3-4)-P(3-4). Weight, height and body mass index, heart rate, blood pressure values were within the 50 percentile 50+/-1SD for their age. The biomarkers were measured in saliva, as a good correlation between saliva and plasma levels has been reported in lipoperoxidation products, reduced glutathione and catalase. RESULTS: Pubescent boys had significantly higher levels of lipoperoxidation products (P<0.001) compared with the prepubertal group, with no significant differences in the other parameters measured. There was a significant positive correlation between lipoperoxides and reduced glutathione in these children. CONCLUSION: It is the first time that an increase of lipoperoxidation products has been reported in pubertal boys and this biomarker could play a role in the development of oxidative stress in this stage of life.

Infection Structures of Host-Specialized Isolates of Uromyces viciae-fabae and of Other Species of Uromyces Infecting Leguminous Crops.

A study was made of the morphology of urediniospores and primary infection structures of 12 isolates of six legume-infecting species of Uromyces. Infection structures were sufficient to distinguish among species. Isolates of Uromyces viciae-fabae proved to be specialized with respect to host, because each isolate infected only cultivars of the species from which it was collected. Host-specialized isolates of U. viciae-fabae also were morphologically distinct, differing in both spore dimensions and infection structure morphology. In particular, the shape and dimensions of the substomatal vesicle were distinctive. These results support the view that U. viciae-fabae sensu lato is a species complex.

Sources of Resistance to Crenate Broomrape Among Species of Vicia.

Crenate broomrape is a parasitic weed that represents a major constraint for pulse and forage legume production in the Mediterranean and West Asia regions. Control strategies have centered around agronomic practices and the use of herbicides, although success has been marginal. Resistance breeding is hampered by scarcity of proper sources of resistance and of a reliable and practical screening procedure. A germ plasm collection of 208 accessions of vetch belonging to 42 Vicia spp. was screened for resistance to crenate broomrape under field conditions. High levels of resistance were found in several species. Resistance of selected accessions was confirmed by a low induction of broomrape seed germination in pot and in vitro experiments. This was followed by a scarce establishment of broomrape radicles in contact with host roots and a limited development of established tubercles. In addition, a hypersensitive-like necrosis occasionally was observed, but at low frequency.

Isolate and organ-specific QTLs for ascochyta blight resistance in faba bean ( Vicia faba L).

The main objective of the present study was to locate the genomic regions responsible for ascochyta blight resistance in faba bean. Six QTLs were identified with the help of a linkage map constructed from a F(2) population from the cross between the inbred lines 29H (resistant) and VF136 (susceptible). Two pathogenically distinct Ascochyta isolates were used to study the genetic control against them and disease evaluations were performed separately on leaves and stems to investigate whether different genetic systems control resistance in each plant organ, as previously suggested. The six QTLs detected were named Af3 to Af8. Af3 and Af4 were effective against both Ascochyta isolates, Af5 was only effective against isolate CO99-01 while Af6, Af7 and Af8 were only effective against isolate LO98-01. Af3, Af4, Af5 and Af7 were revealed in both leaves and stems. By contrast, Af6 was only effective in leaves and Af8 only in stems. The validity and application of these results in a MAS program is discussed.

Identification of RAPD markers linked to the Uvf-1 gene conferring hypersensitive resistance against rust (Uromyces viciae-fabae) in Vicia faba L.

Bulk segregant analysis was used to identify random amplified polymorphic DNA (RAPD) markers linked to a gene determining hypersensitive resistance in Vicia faba line 2N52 against race 1 of the rust fungus Uromyces viciae-fabae. The monogenic nature of the resistance was determined by analyzing the F(2) population from a cross between resistant line 2N52 and susceptible line VF-176, and further confirmed in the F(2:3)-derived families. Linkage of the RAPD markers was confirmed by screening 55 F(2) plants segregating for resistance. Three RAPD markers (OPD13(736), OPL18(1032) and OPI20(900)) were mapped in coupling phase to the resistance gene for race 1 ( Uvf-1). No recombinants between OPI20(900) and Uvf-1 were detected. Two additional markers (OPP02(1172) and OPR07(930)) were linked to the gene in repulsion phase at a distance of 9.9 and 11.5 cM, respectively. The application of marker-assisted selection to develop new faba bean varieties with rust resistance genes is discussed.

Histological Characterization of Resistance to Uromyces viciae-fabae in Faba Bean.

ABSTRACT Components of resistance to the faba bean rust (Uromyces viciae-fabae) were studied at the histological level in seedlings and adult plants of nine faba bean (Vicia faba) lines differing in their level of resistance. Resistance of these lines was previously shown to be characterized macroscopically by an increased latent period, a decreased colony size, and a relatively decreased infection frequency. In some lines, the resistance also was associated with macroscopically visible necrosis. Histological investigations revealed few differences in spore germination and appressorium formation. Significant levels of aborted stomatal penetration by the rust fungus were found on all resistant lines. However, differences among lines were more evident once the stomata were penetrated by the infection structures. Resistance was mainly due to a restriction of haustorium formation with varying levels of early abortion of the colonies, a reduction in the number of haustoria per colony, and smaller colony size. In addition, necrosis of the host cells associated with infection hyphae was detectable in some lines from the beginning of colony development. This microscopically visible necrosis became stronger from 4 days after inoculation, resulting in a reduced growth of the colony. Differences in resistance levels were more marked in adult plants than in seedlings.

Idiopathic pylephlebitis and idiopathic sclerosing peritonitis in a man with protein S deficiency.

Idiopathic pylephlebitis and primary sclerosing peritonitis are two highly unusual entities. To our knowledge, the association of the two diseases has not been described previously. We report a 42-year-old patient with a protein S deficiency who presented with fever and chills, in whom idiopathic pylephlebitis was diagnosed. A year later, the patient was readmitted because of recurrent vomiting and weight loss. An exploratory laparotomy yielded diagnosis of sclerosing peritonitis, which resolved after surgery. The short time interval between the processes suggests that they were related to each other, and also to the protein S deficiency.