12,191 research outputs found
Crystal engineering using functionalized adamantane
We performed a first principles investigation on the structural, electronic,
and optical properties of crystals made of chemically functionalized adamantane
molecules. Several molecular building blocks, formed by boron and nitrogen
substitutional functionalizations, were considered to build zincblende and
wurtzite crystals, and the resulting structures presented large bulk moduli and
cohesive energies, wide and direct bandgaps, and low dielectric constants
(low- materials). Those properties provide stability for such
structures up to room temperature, superior to those of typical molecular
crystals. This indicates a possible road map for crystal engineering using
functionalized diamondoids, with potential applications ranging from space
filling between conducting wires in nanodevices to nano-electro-mechanical
systems
Selection procedures in the development of maize inbred lines and the effects of plant densities on the relationships between inbred traits and hybrid yields
The purpose of this research was to use five selection procedures to develop inbred lines of maize (Zea mays L.):
(1) to compare the selected lines for performance per se and in testcrosses at various plant densities, thereby evaluating the selection procedures; and
(2) to determine the effects of plant densities on the relationships among plant, ear, and grain traits of the inbred lines and between these traits and hybrid yield performance.
The source population was an Iowa Synthetic, BS1. Five groups of lines were obtained: Group 1, selected visually at a density of 59,000 plants/ha in rows spaced 102 cm; Group 2, selected visually and for one ear per plant at a density of 29,500 plants/ha in rows spaced 102 cm; Group 3, selected visually and for two ears per plant at a density of 29,500 plants/ha in rows spaced 102 cm; Group 4, selected visually at a density of 59,000 plants/ha in rows spaced 51 cm; Group 5, selected for testcross performance (double-cross tester) at 59,000 plants/ha in rows spaced 51 cm. Lines in groups 1 to 4 were selected in the S0 to S4 generations and lines in Group 5 in the S0 to S2 generations with some visual selection of the lines and plants when the testcrosses were produced. Nineteen lines in each of groups 1 to 4 and a control (BS1) were evaluated in testcrosses (double-cross tester) in eight environments, three plant densities per environment (Experiment I). Also, the lines in groups 1 to 4, 10 lines in Group 5, and the control were evaluated in testcrosses (double-cross tester) in two environments, 51-cm row width and 59,000 plants/ha (Experiment II)
The prevalence of eating disorders not otherwise specified
Objective: Eating Disorders Not Otherwise Specified (EDNOS) represent the most common eating disorder diagnosed in specialized treatment settings. The purpose of the current study is to assess the prevalence of EDNOS in a nationwide community sample. Method: Participants were 2028 female students, aged 12 to 23, attending public schools in the 9th to 12th grades in Portugal. Participants completed the Eating Disorder Examination Questionnaire in Stage 1 of the study. In Stage 2, we selected all the participants who met any of these criteria: (1) BMI ≤ 17.5, (2) scores ≥ 4 on any of the four EDE-Q Subscales, (3) a total EDE-Q score ≥ 4, or, (4) the presence of dysfunctional eating behaviors. In Stage 2, eating disorder experts interviewed 901 participants using the Eating Disorder Examination. Results: The prevalence of all eating disorders was 3.06% among young females. Prevalence for anorexia nervosa was 0.39%, for bulimia nervosa 0.30%, EDNOS 2.37%. Conclusion: EDNOS is a very common eating disorder and accounts for three-quarters of all community cases with eating disordersFundação para a Ciência e a Tecnologia (FCT
Functional interaction between BMPR-II and Tctex-1, a light chain of Dynein, is isoform-specific and disrupted by mutations underlying primary pulmonary hypertension
Diverse heterozygous mutations of bone morphogenetic receptor type II (BMPR-II) underlie the inherited form of the vascular disorder primary pulmonary hypertension (PPH). As yet, the molecular detail of how such defects contribute to the pathogenesis of PPH remains unclear. BMPR-II is a member of the transforming growth factor-beta cell signalling superfamily. Ligand binding induces cell surface receptor complex formation and activates a cascade of phosphorylation events of intracellular intermediaries termed Smads, which initiate transcriptional regulation. Some 30% of PPH-causing mutations localize to exon 12, which may be spliced out forming an isoform depleted of the unusually long BMPR-II cytoplasmic tail. To further elucidate the consequences of BMPR2 mutation, we sought to characterize aspects of the cytoplasmic domain function by seeking intracellular binding partners. We now report that Tctex-1, a light chain of the motor complex dynein, interacts with the cytoplasmic domain of BMPR-II and demonstrate that Tctex-1 is phosphorylated by BMPR-II, a function disrupted by PPH disease causing mutations within exon 12. Finally we show that BMPR-II and Tctex-1 co-localize to endothelium and smooth muscle within the media of pulmonary arterioles, key sites of vascular remodelling in PPH. Taken together, these data demonstrate a discrete function for the cytoplasmic domain of BMPR-II and justify further investigation of whether the interaction with and phosphorylation of Tctex-1 contributes to the pathogenesis of PPH
Invariant classification and the generalised invariant formalism: conformally flat pure radiation metrics, with zero cosmological constant
Metrics obtained by integrating within the generalised invariant formalism
are structured around their intrinsic coordinates, and this considerably
simplifies their invariant classification and symmetry analysis. We illustrate
this by presenting a simple and transparent complete invariant classification
of the conformally flat pure radiation metrics (except plane waves) in such
intrinsic coordinates; in particular we confirm that the three apparently
non-redundant functions of one variable are genuinely non-redundant, and easily
identify the subclasses which admit a Killing and/or a homothetic Killing
vector. Most of our results agree with the earlier classification carried out
by Skea in the different Koutras-McIntosh coordinates, which required much more
involved calculations; but there are some subtle differences. Therefore, we
also rework the classification in the Koutras-McIntosh coordinates, and by
paying attention to some of the subtleties involving arbitrary functions, we
are able to obtain complete agreement with the results obtained in intrinsic
coordinates. In particular, we have corrected and completed statements and
results by Edgar and Vickers, and by Skea, about the orders of Cartan
invariants at which particular information becomes available.Comment: Extended version of GRG publication, with some typos etc correcte
Effect of Earthworm Manure Fertilisation on Biomass Production and Mineral Content of \u3cem\u3eDigitaria Swazilandensis\u3c/em\u3e
Chemical fertilisers are expensive and can cause environmental contamination, affecting the biodiversity; it is therefore desirable to use organic manure that is cheaper and can be prepared on the same farm. Earthworm manure is the product of worms that transform organic matter (Salinas & Rojas, 1995), which improves the physical, chemical and biological properties of the soil (Pérez, 1993; Ravera & De Sanso, 1999). The importance of these improvements justifies the use of the worm humus in fertilisation programs in grasslands. Therefore, the objective of this experiment was to evaluate the effect of the earthworm manure on the biomass production and minerals concentration of Digitaria swazilandensis
Primary pulmonary hypertension is associated with reduced pulmonary vascular expression of type II bone morphogenetic protein receptor
BACKGROUND: Mutations in the type II receptor for bone morphogenetic protein (BMPR-II), a receptor member of the transforming growth factor-beta (TGF-beta) superfamily, underlie many familial and sporadic cases of primary pulmonary hypertension (PPH).
METHODS AND RESULTS: Because the sites of expression of BMPR-II in the normal and hypertensive lung are unknown, we studied the cellular localization of BMPR-II and the related type I and II receptors for TGF-beta by immunohistochemistry in lung sections from patients undergoing heart-lung transplantation for PPH (n=11, including 3 familial cases) or secondary pulmonary hypertension (n=6) and from unused donor lungs (n=4). In situ hybridization was performed for BMPR-II mRNA. Patients were screened for the presence of mutations in BMPR2. In normal lungs, BMPR-II expression was prominent on vascular endothelium, with minimal expression in airway and arterial smooth muscle. In pulmonary hypertension cases, the intensity of BMPR-II immunostaining varied between lesions but involved endothelial and myofibroblast components. Image analysis confirmed that expression of BMPR-II was markedly reduced in the peripheral lung of PPH patients, especially in those harboring heterozygous BMPR2 mutations. A less marked reduction was also observed in patients with secondary pulmonary hypertension. In contrast, there was no difference in level of staining for TGF-betaRII or the endothelial marker CD31.
CONCLUSIONS: The cellular localization of BMPR-II is consistent with a role in the formation of pulmonary vascular lesions in PPH, and reduced BMPR-II expression may contribute to the process of vascular obliteration in severe pulmonary hypertension
Electronic properties and hyperfine fields of nickel-related complexes in diamond
We carried out a first principles investigation on the microscopic properties
of nickel-related defect centers in diamond. Several configurations, involving
substitutional and interstitial nickel impurities, have been considered either
in isolated configurations or forming complexes with other defects, such as
vacancies and boron and nitrogen dopants. The results, in terms of spin,
symmetry, and hyperfine fields, were compared with the available experimental
data on electrically active centers in synthetic diamond. Several microscopic
models, previously proposed to explain those data, have been confirmed by this
investigation, while some models could be discarded. We also provided new
insights on the microscopic structure of several of those centers.Comment: 21 pages, 8 figure
- …