Hydrogenated amorphous carbon as protective coating for a forming tool

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The use of polylactic and polyglycolic copolymer biomaterial in a pre-clinical model of compromised primary stability

Aim Primary implant stability can be compromised by overdrilling of the implant bed. Filling the gap between the implant and the bone with a highly viscous copolymer of polylactic and polyglycolic acid (PLA/PGA) might stabilize the implant and thus supply osseointegration. The aim of this study was to evaluate implants installed in overdrilled beds associated with PLA/PGA in rats tibia model by means of removal torque test and fluorochrome analysis. Materials and methods For this experiment two groups were selected: in the test group 0.4 mm overdrilled defects (2.0 in diameter and 3 mm long ) were produced in the right tibia of seven rats and implants were placed covered with PLA/PGA biomaterial to fill the gap; the control group was not overdrilled and the implants were placed without the biomaterial. Implants of 1.6 mm in diameter and 3 mm long where placed into all defects. Calcein, alizarin and oxytetracyclin were injected at 7, 15 and 21 postoperative days, respectively, and the animals were sacrificed at 35 postoperative day. Results The results showed that all the implants achieved osseointegration. There were no statistical significance differences in torque-reverse and fluorocrome analysis (P>0.05). Conclusion We can conclude that overdrilled defects filled with PLA/PGA did not disturb osseointegration in this experimental model. © ARIESDUE.

Plasma-polymerized acetylene nanofilms modified by nitrogen ion implantation

Thin films were prepared by plasma enhanced chemical vapour deposition (PECVD) from a mixture of acetylene and argon, and post deposition-treated by plasma immersion ion implantation (PIII). The effect of PIII on the nanofilms properties was evaluated as a function of treatment time. The average thickness and roughness were diminished upon PIII. On the other hand, hardness (0.7-3.9 GPa) and elastic modulus (29-54 GPa) increased upon 60 min of ion bombardment. Such results are ascribed mainly to the densification of the film structure caused by the increment in the crosslinking degree with increasing the energy deposited in the films. Wettability of the samples, investigated by contact angle measurements, was reduced (from 64 to 21°) right after PIII. This result, attributed to the introduction of polar groups in the film structure, was not preserved as the sample was aged in atmosphere. After aging, contact angles were larger than 70° but still smaller than 90°. Although the wettability has decreased with aging, the hydrophilic character of the samples was preserved. For certain treatment times, nitrogen PIII turned the plasma-polymerized acetylene films smoother, denser, mechanically and tribologicaly more resistant than the as-deposited material. © 2013 Elsevier B.V.

Preparation of films from aluminum acetylacetonate by plasma sputtering

Aluminum acetylacetonate has been reported as a precursor for the deposition of alumina films using different approaches. In this work, alumina-containing films were prepared by plasma sputtering this compound, spread directly on the powered lowermost electrode of a reactor, while grounding the substrates mounted on the topmost electrode. Radiofrequency power (13.56 MHz) was used to excite the plasma from argon atmosphere at a working pressure of 11 Pa. The effect of the plasma excitation power on the properties of the resulting films was studied. Film thickness and hardness were measured by profilometry and nanoindentation, respectively. The molecular structure and chemical composition of the layers were analyzed by Fourier transform infrared spectroscopy and energy dispersive spectroscopy. Surface micrographs, obtained by scanning electron microscopy, allowed the determination of the sample morphology. Grazing incidence X-ray diffraction was employed to determine the structure of the films. Amorphous organic layers were deposited with thicknesses of up to 7 μm and hardness of around 1.0 GPa. The films were composed by aluminum, carbon, oxygen and hydrogen, their proportions being strongly dependent on the power used to excite the plasma. A uniform surface was obtained for low-power depositions, but particulates and cracks appeared in the high-power prepared materials. The presence of different proportions of aluminum oxide in the coatings is ascribed to the different activations promoted in the metalorganic molecule once in the plasma phase. Copyright © 2013 John Wiley & Sons, Ltd. Copyright © 2013 John Wiley & Sons, Ltd.

Mechanical and tribological properties of a-C:H:F Thin Films

a-C:H films were grown by plasma-enhanced chemical vapor deposition in atmospheres composed by 30 % of acetylene and 70 % of argon. Radiofrequency signal (RF) was supplied to the sample holder to generate the depositing plasmas. Deposition time and pressure were chosen 300 s and 9.5 Pa, respectively, while the excitation power changed from 5 to 125 W. The films were exposed to a post-deposition treatment during 300 s in RF-plasmas (13.56 MHz, 70 W) excited from 13.33 Pa of SF6. Raman and X-ray photoelectron spectroscopy were used to evaluate the microstructure and chemical composition of the films. The thickness was measured by perfilometry. Hardness and friction coefficient were determined from nanoindentation and risk tests, respectively. With increasing power, the film thickness reduced, but a further shrinkage occurred upon the fluorination process. After that, the molecular structure was observed to vary with deposition power. Fluorine was detected in all samples replacing H atoms. Consistently with the elevation in the proportion of C atoms with sp3 hybridization, hardness increased from 2 to 18 GPa. Friction coefficient also increased with power due to the generation of dangling bonds during the fluorination process. © 2012 Springer Science+Business Media, LLC.

Nanocompósitos baseados no sistema epoxídico DEGBA/DETA modificado com uma resina epoxídica de silsesquioxano

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeito da Hidroxiuréia, uma substância de uso médico, sobre parâmetros biológicos de Drosophila melanogaster

Pós-graduação em Genética - IBILCE

Perfil genético e microbiológico de cepas de Escherichia coli isoladas de leite mastítico bovino

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

De Bush a Jack Bauer: a segurança como obsessão nos Estados Unidos após o 11 de setembro

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Síntese e tratamento de materiais a plasma

Neste trabalho são apresentados resultados que demonstram algumas das possibilidades de processamento de materiais por técnicas de plasma. O primeiro conjunto de dados relata o efeito da potência de excitação do plasma na microestrutura e nas propriedades óticas e elétricas de filmes de carbono amorfo hidrogenado depositados em atmosferas de acetileno e argônio. Neste estudo, correlações entre as propriedades dos filmes e da fase plasma são realizadas com base nas caracterizações elétricas e óticas do plasma. Observa-se que a potência do sinal de excitação afeta diretamente a densidade de energia do plasma e, por conseguinte, as propriedades dos filmes. Variações nas proporções de hidrogênio e de sítios com hibridização sp2 foram constatadas. Filmes relativamente transparentes e com elevada resistência elétrica foram obtidos em plasmas de 50 W de potência. Na segunda etapa, discute-se o efeito da implantação iônica por imersão em plasmas nas propriedades de filmes de polímeros preparados em descargas de radiofreqüência de benzeno. As amostras foram expostas, por diferentes tempos, ao plasma de imersão de argônio e o comportamento da composição química, dureza, propriedades óticas e termodinâmicas de superfície dos filmes foi obtido em função do tratamento. Os filmes tornaram-se mais absorvedores e duros revelando perda de hidrogênio e aumento no grau de reticulação e de insaturação das cadeias carbônicas com o aumento do tempo de bombardeamento. Na parte final, demonstra-se a versatilidade e efetividade da técnica híbrida de implantação iônica e deposição por imersão em plasmas, na produção de filmes com diferentes composições químicas e propriedades de superfície, em função da proporção de gases nobres e reativos na descarga...

DNA for nano-bio scale computation of chemical formalisms using Higher Order Logic (HOL) and analysis using an interdisciplinary approach

Bio-molecular computing, 'computations performed by bio-molecules', is already challenging traditional approaches to computation both theoretically and technologically. Often placed within the wider context of ´bio-inspired' or 'natural' or even 'unconventional' computing, the study of natural and artificial molecular computations is adding to our understanding of biology, physical sciences and computer science well beyond the framework of existing design and implementation paradigms. In this introduction, We wish to outline the current scope of the field and assemble some basic arguments that, bio-molecular computation is of central importance to computer science, physical sciences and biology using HOL - Higher Order Logic. HOL is used as the computational tool in our R&D work. DNA was analyzed as a chemical computing engine, in our effort to develop novel formalisms to understand the molecular scale bio-chemical computing behavior using HOL. In our view, our focus is one of the pioneering efforts in this promising domain of nano-bio scale chemical information processing dynamics.

The Iowa Award Recipients from the Iowa Official Register, 2013-2014

The Iowa Award represents the state’s highest citizen award. The Iowa Centennial Memorial Foundation, established in 1948 by Governor Robert D. Blue and the Iowa General Assembly, created the award. The foundation wished “to encourage and recognize the outstanding service of Iowans in the fields of science, medicine, law, religion, social welfare, education, agriculture, industry, government, and other public service” and to recognize the “merit of their accomplishments in Iowa and throughout the United States.”

Iso-Britannia vastakumouksellisessa sodassa : turvallisuusjoukkojen käyttöperiaatteet Malaijalla (1948-1960) ja Keniassa (1952-1960)

Toisen maailmansodan jälkeisenä ajanjaksona Iso-Britannia joutui useisiin vastakumouksellisen sodankäynnin konflikteihin siirtomaarakenteiden purkautumisen ja maailmanpoliittisen tilanteen johdosta. Tutkielma käsittelee Ison-Britannian turvallisuusjoukkojen käyttöperiaatteita vastakumouksellisen sodankäynnin konflikteissa Malaijalla vuosina 1948–1960 ja Keniassa vuosina 1952–1960. Tutkimus on luonteeltaan kvalitatiivinen tutkimus. Tutkimusmenetelmänä on käytetty lähdeaineistoon perustuvaa sisällönanalyysia. Lähdeaineisto koostuu pääsääntöisesti ulkomaalaisissa sotakouluissa tehdyistä opinnäytetöistä sekä tutkimus- ja aikalaiskirjallisuudesta. Lisäksi lähteenä on käytetty Britannian asevoimien ohjesääntöjä vastakumouksellisesta sodankäynnistä. Britannian vastakumouksellisen sodankäynnin taisteluoppi korosti sodan poliittista ratkaisua. Toisen maailmansodan jälkeisessä taisteluopissa uhkamalli muodostui Mao Tse-Tungin oppien mukaisesti taistelevasta kumouksellisesta liikkeestä. Malaijalla ja Keniassa kumouksellisen toiminnan raamit olivat monin osin yhtenäiset. Kapinalliset pystyttiin määrittämään selväksi vähemmistöryhmittymäksi koko kansakunnan osalta. Kapinallisten toiminta- aluetta olivat pääsääntöisesti maiden rajojen sisäpuolelle rajoittuvat harvaan asutut viidakko- ja metsäalueet. Britannian turvallisuusjoukkojen toiminnan perustana ollut ohjesääntö määritteli turvallisuusjoukkojen tärkeimmäksi tehtäväksi kumouksellisten eristämisen väestöstä, minkä avulla kumouksellisilta riistettiin toimintansa kannalta elintärkeät resurssit. Poliisivoimilla sekä paikallisesta väestöstä perustetuilla kodinturvajoukoilla kontrolloitiin ja valvottiin asuttuja alueita sotilasvoimien suorittaessa operaatioita viidakko- ja metsäalueiden laitamilla ja syvyydessä. Samanaikaisesti toteutetut uudelleenasuttamisen ohjelmat ja elintarvikkeiden säätelyt vaikeuttivat kapinallisten tukeutumista väestöön ja pakottivat heidät vetäytymään syrjäseuduille. Tutkielman tärkeimpänä havaintona voidaan pitää turvallisuusjoukkojen käyttöperiaatteiden yhtäläisyyttä Malaijalla ja Keniassa. Turvallisuusjoukkojen rakenne ja periaatteellinen käyttö noudattivat molemmissa konflikteissa samaa kaavaa perustuen Malaijan alkuvuosien havaintojen pohjalta laadittuun käsikirjaan. Turvallisuusjoukkojen käyttöön vaikuttaneet asteittaiset toimenpiteet kapinallisten eristämiseksi väestöstä, johtaen aina heidän voimiensa lopulliseen tuhoamiseen, olivat käyttöperiaatteiden kannalta ohjaava tekijä. Konflikteista saatujen havaintojen perusteella pystyttiin määrittelemään turvallisuusjoukkojen toimijoille selkeät roolit ja tehtäväkentät kriisien eri vaiheissa.