Related chromosome binding sites for zeste, suppressors of zeste and Polycomb group proteins in Drosophila and their dependence on Enhancer of zeste function

Polycomb group genes are necessary for maintaining homeotic genes repressed in appropriate parts of the body plan. Some of these genes, e.g. Psc, Su(z)2 and E(z), are also modifiers of the zeste-white interaction. The products of Psc and Su(z)2 were immunohistochemically detected at 80-90 sites on polytene chromosomes. The chromosomal binding sites of these two proteins were compared with those of zeste protein and two other Polycomb group proteins, Polycomb and polyhomeotic. The five proteins co-localize at a large number of sites, suggesting that they frequently act together on target genes. In larvae carrying a temperature sensitive mutation in another Polycomb group gene, E(z), the Su(z)2 and Psc products become dissociated from chromatin at non-permissive temperatures from most but not all sites, while the binding of the zeste protein is unaffected. The polytene chromosomes in these mutant larvae acquire a decondensed appearance, frequently losing characteristic constrictions. These results suggest that the binding of at least some Polycomb group proteins requires interactions with other members of the group and, although zeste can bind independently, its repressive effect on white involves the presence of at least some of the Polycomb group proteins.     

Thermal characterization of wood of nine European tree species: thermogravimetry and differential scanning calorimetry in an air atmosphere

European Journal of Wood and Wood Products - This paper presents a thermal characterization of hardwoods of Hungarian origin. The study covers the wood of the following tree species: sessile oak...     

Exploring AppInventory,a visual catalog of applications for assisting teachers and students

Multimedia Tools and Applications - We are witnessing a meaningful transformation of teaching and learning practices and widespread experimentation of new didactic methodologies. The availability...     

Comparison of methanol to gasoline conversion in one-step,two-step,and cascade mode in the presence of H-ZSM-5 zeolite

In this report, three technological modes for methanol-to-gasoline reaction in the presence of H-ZSM-5 catalyst are compared: (i) direct methanol transformation to hydrocarbons; (ii) two-step (methanol-dimethyl ether-hydrocarbons); and (iii) cascade pathway. Light hydrocarbon gases (methane, ethylene, propylene, and isobutene) and liquid aromatic hydrocarbons (benzene, toluene, xylene, cresol, durol, naphthalene, methylnaphthalene, ethyl naphthalene, isopropyl naphthalene, methyl isopropyl naphthalene, etc.) were found to be the main reaction products. The experimental results showed that the classical two-step methanol to gasoline (MTG) process nowadays remains the most effective for gasoline-range hydrocarbons production, while one-step and cascade schemes require further investigation and the development of reactor systems as well as the operating conditions. The product distribution of MTG synthesis after 120?h on stream in the case of two-step mode was found to be the following: liquid C₆–C₈ hydrocarbons – 23%; C₁–C₅ gaseous products – 65%; heavy C₉–C₁₂ hydrocarbons – 10%.     

Detection of neuroblastoma in the bone marrow: biopsy versus aspiration

OBJECTIVES: To determine the clinical effects of a change from postural drainage (PD) to positive expiratory pressure chest physiotherapy (PEP) in children with cystic fibrosis (CF) and symptoms of gastro-oesophageal reflux (GOR). To measure the effects of PD on GOR in children with CF. METHODS: Study 1: Six adolescents with CF and symptoms of GOR during PD were changed to upright PEP physiotherapy. The effects on lung function, reflux symptom scores and annual hospital days were measured. Study 2: Twenty-four children with CF (mean age 11 years) and symptoms suggestive of GOR underwent 24-h pH monitoring, including periods of chest physiotherapy. RESULTS: Study 1: All six patients reported a reduction in reflux symptoms during PEP therapy (P < 0.001). Lung function parameters improved during the first 6 months of PEP (P < 0.001). This improvement was sustained for a further 18 months. Annual hospital days decreased significantly (P < 0.0005). Study 2: Nine of 24 patients (37.5%) had pathological GOR. Reflux episodes were significantly increased during PD (P < 0.0001), as was fractional reflux time (P < 0.01). CONCLUSIONS: Upright PEP physiotherapy may be more appropriate than PD in selected patients with CF and symptomatic GOR. The role of GOR as a cofactor in the progression of pulmonary disease in CF needs further evaluation.     

Successive-ganzfeld haploscopic viewing technique for color-appearance research

A new experimental technique for color appearance research is described. This technique, successive-Ganzfeld haploscopic viewing, combines advantages of traditional haploscopic and successive-haploscopic techniques with modifications that provide a more amenable viewing situation for the observer. This note reviews the need for haploscopic viewing techniques in color appearance research and the pros and cons of traditional techniques. and outlines the implementation of the new technique along with current and potential applications.     

Visco-elastic behavior through fractional calculus: An easier method for best fitting experimental results

In capturing visco-elastic behavior, experimental tests play a fundamental rule, since they allow to build up theoretical constitutive laws very useful for simulating their own behavior. The main challenge is representing the visco-elastic materials through simple models, in order to spread their use. However, the wide used models for capturing both relaxation and creep tests are combinations of simple models as Maxwell and/or Kelvin, that depend on several parameters for fitting both creep and relaxation tests. This paper, following Nutting and Gemant idea of fitting experimental data through a power law function, aims at stressing the validity of fractional model. In fact, as soon as relaxation test is well fitted by power law decay then the fractional constitutive law involving Caputo’s derivative directly appears. It will be shown that fractional model is proper for studying visco-elastic behavior, since it may capture both relaxation and creep tests, requiring the identification of two parameters only. This consideration is assessed by the good agreement between experimental tests on creep and relaxation and the fractional model proposed. Experimental tests, here reported are performed on two polymers having different chemical physical properties such that the fractional model may cover a wide range of visco-elastic behavior.