Electronic and structural properties of fluorene-thiophene copolymers as function of the composition ratio between the moieties: a theoretical study.

Through theoretical analysis, we study relevant properties of some molecular structures formed by oligothiophenes (T) and dioctylfluorenes (F) units, commonly employed in the fabrication of different kinds of optical and electronic devices. For so, we first consider F-(T)n-F molecules with different numbers of thiophene rings (n). Among other characteristics, we calculate the dipole moment change between the ground and excited state (Δµge), a quantity that greatly influences the exciton dissociation and charge carrier mobility. We show that the planarity of the ground state geometry correlates Δµge to the exciton binding energy (Eb), with higher Δµge's corresponding to lower Eb's when n > 3. We also unveil a relevant dependence of Δµge with the odd-even parity of n and that Δµge assumes higher values when the molecule is composed by bithiophene (instead of simple thiophenes) moieties in the syn-conformation (with the two heteroatoms pointing in the same direction). From molecules results, we then address larger systems, formed by different oligomers of F-T copolymers containing blocks of dioctylfluorenes and bithiophenes (T2). We systematic investigate their electronic and structural properties as function of the composition ratio between the T2 and F moieties. Similar to the molecules, we deduce that the magnitude of Δµge is higher for the syn conformer of the T2 unit. Moreover, the highest values of Δµge are achieved when the number of the T2 increases relative to a fixed number of the F units in the mer. Such behaviors are in agreement and actually can qualitative explain measurements in the literature on the quantum efficiency of charge carrier generation in F-T copolymers. The present findings can be helpful in designing novel materials with improved photoelectric responses.

Antibacterial efficacy and mechanisms of action of low power atmospheric pressure cold plasma: membrane permeability, biofilm penetration and antimicrobial sensitization.

AIM: The objective of this study was to determine the efficacy and mechanisms of inactivation of two clinically relevant ESKAPE bacteria namely Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus by atmospheric pressure cold plasma. METHODS AND RESULTS: Plasma was generated between two brass grids by applying a radiofrequency electric field to a flow of helium. Intracellular generation of reactive species, alterations in cell membrane, and inactivation of bacteria in planktonic or biofilm growth were studied. Results were compared with commonly used antimicrobial drugs. Plasma exposure generated reactive oxygen and nitrogen species in bacteria, disrupted membrane integrity and reduced bacterial load. The efficacy in bacterial inactivation was comparable to antibiotics but exhibited a quicker killing rate. The antibacterial effect of plasma synergistically increased in association with antibiotics and did not diminish over repeated exposures, suggesting no development in bacterial resistance. CONCLUSIONS: Through generation of reactive species, cold plasma altered cell membrane and effectively inactivated clinically important bacteria, both in suspension and in biofilms. SIGNIFICANCE AND IMPACT OF THE STUDY: As cold plasma damages different targets in bacterial cells, it emerges as an effective strategy used alone or in combination with antimicrobial drugs to control microbial infections and prevent the selection of resistant bacterial strains.

Cyrtoneurina pararescita (Diptera: Muscidae) (Couri, 1995) como novo hospedeiro de Nasonia vitripennis (Walker) (Hymenoptera: Pteromalidae) / Cyrtoneurina pararescita (Diptera: Muscidae) (Couri, 1995) as new host of Nasonia vitripennis (Walker) (Hymenoptera: Pteromalidae)

This study reports the occurrence of Nasonia vitripennis (Walker) (Hymenoptera: Pteromalidae) as parasitoid of Cyrtoneurina pararescita (Diptera: Muscidae) (Couri, 1995) in bovine feces obtained in Goiânia, Goiás state, Brazil. Bovine manure samples, collected at two weeks intervals, were taken to the laboratory and the pupae were extracted by water flotation. Each pupa was placed in capsules of gelatin until the emergence of dipterous or their parasitoids. The parasitism percentage was of 2.4%. This paper reports the first occurrence of N. vitripennis as parasitoid of C. pararescita worldwide.

Controlling tetragonality and crystalline orientation in BaTiO3 nano-layers grown on Si.

A hybrid growth process was developed in order to epitaxially integrate nano-layers of the multi-functional perovskite BaTiO3 onto Si(001) substrates. In particular, we combined molecular beam epitaxy (MBE) with radio-frequency sputtering. Due to its strong influence on the functional properties, the crystalline structure of the layers was thoroughly investigated throughout our study. MBE-grown seed layers are tetragonal and c-axis oriented up to a thickness of 20 nm. A transition into a-axis films is visible for thicker layers. When the seed layer thickness exceeds 6 nm, subsequently sputtered BaTiO3 films are epitaxial. However, their crystalline structure, their orientation with respect to the substrate, and their morphology are strongly dependent on the deposition and post-deposition thermal budget. Consistently with their crystalline symmetry, thin MBE BaTiO3 films are piezo- and ferroelectric with a spontaneous polarization perpendicular to the surface. Also for thick films, the functional response, as determined via piezo-force microscopy, is in good agreement with the structural properties.

Parasitoides de Ornidia obesa Fabricius (Diptera: Syrphidae) coletados em fezes de galinha no Brasil / Parasitoids of Ornidia obesa Fabricius (Diptera: Syrphidae) collected in chicken feces in Brazil

This study reports the occurrence of Pachycrepoideus vindemmiae (Rondani) (Hymenoptera: Pteromalidae) and Spalangia cameroni Perkins (Hymenoptera: Pteromalidae) as parasitoids of Ornidia obesa Fabricius (Diptera: Syrphidae) in poultry farms in Morrinhos, Goiás, state Brazil. Samples of chicken feces were collected at two weeks intervals and taken to the laboratory. The pupae were extracted by water flotation. Each pupa was placed in capsules of gelatin until the emergence of dipterous or their parasitoids. The parasitism percentage of P. vindemmiae and S. cameroni was 5.1 percent.

Sinantropia de parasitoides de dípteros coletados em fezes bovinas / Synanthropy of dipterous parasitoids collected in cattle dung

The synanthropic indexes of Diptera parasitoid present in forest, rural, and urban areas were determined in the municipality of Monte Alegre, MG, from March to November 2006. The dipterous pupae were obtained by the flotation method and individually placed in gelatin capsules until the emergence of the dipterous and/or their parasitoids. The synanthropic indexes of parasitoid Kleidotoma nigra (Hartig) (Hymenoptera: Figitidae), Paraganaspis egeria Díaz, Gallardo & Walsh (Hymenoptera: Figitidae), Spalangia cameroni Perkins (Hymenoptera: Pteromalidae), Trichopria sp. (Hymenoptera: Diapriidae), Triplasta atrocoxalis (Ashmead) (Hymenoptera: Figitidae), and Triplasta coxalis (Ashmead) (Hymenoptera: Figitidae) were +0.1, -100, +50, +100, -3, and -100, respectively.

Functional organ preservation in patients with locoregionally advanced head and neck squamous cell carcinoma treated by platinum-based multidrug induction chemotherapy and concurrent chemoradiotherapy.

BACKGROUND: The objective of this study was to evaluate the feasibility, safety, and efficacy in terms of functional organ preservation of multidrug induction chemotherapy and concurrent chemoradiotherapy (IC-CCRT) protocol in patients with locoregionally advanced head and neck squamous cell carcinoma (LA-HNSCC). PATIENTS AND METHODS: Patients with previously untreated, inoperable, histologically proven nonmetastatic stage III or IV HNSCC were eligible. Following one cycle of IC, two cycles of cisplatinum and 5-fluorouracil CCRT with conventional fractionated radiotherapy up to a dose of 66-70 Gy were administrated. RESULTS: Between January 2000 and July 2007, a total of 139 patients were candidates to receive IC-CCRT for LA-HNSCC. Overall, 83% of the patients completed the treatment. Three-year overall survival estimate was 68% [95% confidence interval (CI) 57% to 79%]. Three-year progression-free survival (PFS) estimate was 62% (95% CI 50% to 74%). Three-year functional PFS was 57% (95% CI 44% to 69%). There were no cases of treatment-related deaths. The most frequent severe acute toxicity was pharyngeal mucositis. CONCLUSIONS: Cisplatinum-based multidrug IC-CCRT can result in functional organ preservation and curative treatment in most patients with LA-HNSCC. The toxicity profile and patients' compliance to treatment confirmed the safety and tolerability of this approach.

Parasitoides de dípteros coletados em excrementos de animais no sul de Goiás / Parasitoids of dipterous collected in animal excrements in Southern Goiás, Brazil

This study determined the species of microhymenopterous of Diptera present in cattle and buffalo dung, from May 2003 to June 2004 and from April 2006 to March 2007 in chicken manure. All samples were collected in Southern Goiás State, Brazil. The dipterous pupae were obtained by the flotation method. They were individually placed in gelatin capsules until the emergence of the flies and/or their parasitoids. The percentages of parasitism in cattle dung and chicken manure were 12.4% and 10.0%, respectively.

Primeiro relato de Muscidifurax raptorellus Kogan & Legner, 1970 (Hymenoptera: Pteromalidae) no Brasil / First report of Muscidifurax raptorellus Kogan & Legner, 1970) (Hymenoptera: Pteromalidae) in Brazil

This study reports the first occurrence of Muscidifurax raptorellus (Hymenoptera: Pteromalidae) in Brazil. Chicken manure samples, collected at two-week interval, were taken to the laboratory and the pupae were extracted by the method of flotation. Each pupa was placed in capsules of colorless gelatin until the emergence of dipterous or their parasitoids. In the study, ten pupae of Fannia pusio (Wiedemann, 1830) (Diptera: Fanniidae) were obtained, two of which yielded the parasitoid M. raptorellus . The percentage of parasitism was 5.0 percent.

Parasitóides de Diptera coletados em áreas florestal, rural e urbana em Monte Alegre, MG / Parasitoids of Diptera collected in forest, rural, and urban areas in Monte Alegre, MG

This study determined the species of parasitoids of Diptera present in forest, rural, and urban areas in the municipality of Monte Alegre, MG, from March to November 2006. The percentages of parasitism in forest, rural, and urban areas were 14.3 percent, 11.0 percent, and 18.8 percent, respectively. The most frequent species (34.7 percent) was Triplasta atrocoxalis (Ashmead) (Hymenoptera: Figitidae).

Hospedeiros de Triplasta atrocoxalis (Ashmead) (Hymenoptera: Figitidae: Eucoilinae) coletados em fezes de bovinos e búfalos no Brasil / Hosts of Triplasta atrocoxalis (Ashmead) (Hymenoptera: Figitidae: Eucoilinae) colletected in cattle and buffalo dung in Brazil

This study verified the percentage of parasitism and hosts species of the parasitoid Triplasta atrocoxalis (Ashmead) (Hymenoptera: Figitidae: Eucoilinae) in cattle and buffalo dung, collected in the South of Goiás state, Brazil; from January 1998 to June 2004. The pupae were obtained by the flotation method. They were individually placed in gelatin capsules until the emergence of adult dipterous or their parasitoids. The percentage of parasitism in cattle and buffalo dung was 2.5 percent percent and 0.1 percent, respectively.

Parasitóides de dípteros coletados em fezes de búfalos em uma propriedade rural em Itumbiara, Goiás / Parasitoids of dipterous collected in buffalo dung in a rural property in Itumbiara, Goias, Brazil

The species of microhimenopterous in pupae of Diptera present in buffalo dung, collected in the municipality of Itumbiara, GO, from May 2003 to June 2004 were determined. The dipterous pupae were obtained by the flotation method. They were individually placed in gelatin capsules until the emergence of the dipterous and/or their parasitoids. The overall percentage of parasitism was 5.0 percent. The more frequent species were: Spalangia drosophilae Ashmead (Hymenoptera: Pteromalidae) with 21.5 percent and Paraganaspis egeria Díaz & Gallardo (Hymenoptera: Figitidae) with 16.3 percent

Eurytoma sp. (Hymenoptera: Pteromalidae) como parasitóide de Fannia pusio (Wiedemann) (Diptera: Fanniidae) no Brasil / Eurytoma sp. (Hymenoptera: Pteromalidae) as a parasitoid of Fannia pusio (Wiedemann) (Diptera: Fanniidae) in Brazil

This study reports, for the first time, the occurrence of Eurytoma sp. (Hymenoptera: Pteromalidae) as parasitoid of Fannia pusio (Wiedemann) (Diptera: Fanniidae) found in chicken dung in Itumbiara, Goiás, Brazil. Manure samples, collected at two weeks intervals, were taken to the laboratory and the pupae were extracted by water flotation. Each pupa was placed in capsules of colorless gelatin until the emergence of dipterous or their parasitoids. The parasitism was 1.3 percent