1,439 research outputs found

    Computational model to predict the temperature distribution produced by bone cement

    Get PDF
    Bone is the third frequent location for haematogenous dissemination of malignant tumors. Patients with multiple bone metastases are exponentially growing. Bone metastases, which are frequently diagnosed late, are associated to imminent and pathological bone fractures. Metastatic disease translates an advanced tumor stage and it has a high impact in patients’ quality of life and survival. The main objective is to study the thermal effect induced by the bone cement polymerization, in the bone metastatic tumor reduction and to understand the role of such procedure and its biomechanical stabilization. To assess the clinical effect, it is important to test this methodology before its application and obtain sustained results. In this work, a computational model was developed to predict the temperature distribution produced by cement polymerization, and verify the reduction of the metastatic tumor area due the thermal effect. Different simulations produced to evaluate the necrosis effect for two cement amount sizes introduced in a cortical and spongy bone tumor. The same computational models were reproduced introducing an endomedular nail in titanium and a femoral stem in cobalt-chrome material in pathological bone fractures.info:eu-repo/semantics/publishedVersio

    The art of HIV elimination: past and present science

    Get PDF
    Introduction: Remarkable strides have been made in controlling the HIV epidemic, although not enough to achieve epidemic control. More recently, interest in biomedical HIV control approaches has increased, but substantial challenges with the HIV cascade of care hinder successful implementation. We summarise all available HIV prevention methods and make recommendations on how to address current challenges. Discussion: In the early days of the epidemic, behavioural approaches to control the HIV dominated, and the few available evidence-based interventions demonstrated to reduce HIV transmission were applied independently from one another. More recently, it has become clear that combination prevention strategies targeted to high transmission geographies and people at most risk of infections are required to achieve epidemic control. Biomedical strategies such as male medical circumcision and antiretroviral therapy for treatment in HIV-positive individuals and as preexposure prophylaxis in HIV-negative individuals provide immense promise for the future of HIV control. In resourcerich settings, the threat of HIV treatment optimism resulting in increased sexual risk taking has been observed and there are concerns that as ART roll-out matures in resource-poor settings and the benefits of ART become clearly visible, behavioural disinhibition may also become a challenge in those settings. Unfortunately, an efficacious vaccine, a strategy which could potentially halt the HIV epidemic, remains elusive. Conclusion: Combination HIV prevention offers a logical approach to HIV control, although what and how the available options should be combined is contextual. Therefore, knowledge of the local or national drivers of HIV infection is paramount. Problems with the HIV care continuum remain of concern, hindering progress towards the UNAIDS target of 90-90-90 by 2020. Research is needed on combination interventions that address all the steps of the cascade as the steps are not independent of each other. Until these issues are addressed, HIV elimination may remain an unattainable goal

    Controlling Factors Determining The Selective Hscn Addition To Double Bonds And Their Application To The Synthesis Of 7-isothiocyano-7,8-α-dihydro-bisabolene

    Get PDF
    The reactivity of terminal and trisubstituted double bonds of monoterpenes with HSCN has been examined by GC giving evidence that kinetics is responsible for the chemoselective addition to terminal double bonds in terpenes. The results show that the addition to the terminal double bond is about 17 times faster than for trisubstituted double bonds and that the presence of the first SCN group in the molecule prevents a second addition. The presence of a hydroxyl or methoxy group in the molecule, decreases the reaction kinetics. Based on these kinetic experiments a two steps synthesis of the natural product 7-isothiocyano-7,8-dihydro-α-bisabolene using bisabolol as starting material, was planned and successfully accomplished.125661666Drobnica, L., Kristían, P., Augustín, J., The Chemistry of the Cyanates and Their Thio Derivatives, , Saul Patai Ed., John Wiley & Sons, New YorkEdenborough, M.S., Herbert, R.B., (1988) Nat. Prod., p. 229Faulkner, D.J., (1994) Nat. Prod., p. 355(1993) Nat. Prod., p. 497(1992) Nat. Prod., p. 323(1991) Nat. Prod., p. 97(1990) Nat. Prod., p. 269(1988) Nat. Prod., p. 613Fraga, B.M., (1994) Nat. Prod. Rep., p. 533Piers, E., Young, B.W.A., Rettig, S.J., (1987) Tetrahedron, 43 (23), p. 5521Piers, E., Yeung, B.W., (1986) Can. J. Chem., 64, p. 2475Chenera, B., Chuang, C.P., Hart, D.J., Lai, C.S., (1992) J. Org. Chem., 57, p. 2018Da Silva, C.C., Almagro, V., Zukerman-Schpector, J., Castellano, E.E., Marsaioli, A.J., (1994) J. Org. Chem., 59, p. 2880Da Silva, C.C., Almagro, V., Marsaioli, A.J., (1993) Tetrahedron Lett., 34, p. 6717Martin, V.S., Woodward, S.S., Katsuki, T., Yamada, Y., Ikeda, M., Sharpless, K.B., (1981) J. Am. Chem. Soc., 103, p. 6237Rakels, J.L., Straathof, A.J.J., Heijnin, J.J., (1993) Enzyme Microb. Technol, 15, p. 1051Diveley, W.R., Buntin, G.A., (1969) J. Org. Chem., 34, p. 616Queiroga, C.L., Ferracini, V.L., Marsaioli, A.J., (1996) Phytochemistry, 42, p. 1097(-)Bisabolol (8) [(αS, 1S)-1-methanol-α,4-dimethyl-α-4-methyl-3-pentenyl-3-cyclohexene] was obtained from commercial candeia oil (CITRÓLEO - S.Paulo, SP, Brazil)Sullivan, B.W., Faulkner, D.J., Okamoto, K.T., Chen, M.H.M., Clardy, J., (1986) J. Org. Chem., 51, p. 5134Dubois, J.E., Lomas, J.S., (1971) Tetrahedron Lett., 7, p. 599Delay, F., Ohloff, F., (1979) Helv. Chem. Acta, 62, p. 326A sample of dihydrolimonene was kindly provided by Prof. Marcio C. S. de Mattos from IQ/UFRJ, RJ, Brazi

    Application of chemometric tools for the comparison of volatile profile from raw and roasted regional and foreign almond cultivars (Prunus dulcis)

    Get PDF
    In almonds, volatile compounds are major contributors to flavour, being scarce the current knowledge about their volatile profile. Hence, this work intended to characterize the volatile profile, using headspace solidphase microextraction and gas chromatography–mass spectrometry, in raw and roasted almond cultivars (regional cvs. Amendoa˜o, Bonita, Casanova, Molar and Pegarinhos and foreign cvs. Ferragne`s and Glorieta). Overall, 35 compounds were identified, with major chemical classes being alcohols and aldehydes. In raw fruits, benzaldehyde and 3-methyl-1-butanol were key compounds, with roasting changing volatile profiles, increasing release of compounds, with predominance of hexanal and benzaldehyde. Cultivars Glorieta and Molar didn’t show significant increase in aldehyde content after roasting, which may indicate higher resistance to heat-caused oxidation. The use of linear discriminant analysis and principal components analysis permitted the recognition of patterns in the volatile profiles, that can be useful for cultivars identification. This work allowed the characterization and monitoring changes caused by roasting of volatile components of less studied almond cultivars, identifying some that can withstand roasting procedures with reduced formation of compounds associated with off-flavours.Ivo Oliveira is grateful to FCT, POPH-QREN and FSE for the Post-doctoral Fellowship SFRH/BPD/111005/2015. This work is supported by: European Investment Funds by FEDER/ COMPETE/POCI—Operational Competitiveness and Internacionalization Programme, under Project POCI-01-0145-FEDER-006958 and National Funds by FCT—Portuguese Foundation for Science and Technology, under the Project UID/AGR/04033/2013.info:eu-repo/semantics/publishedVersio

    Repeated exposure of adolescent rats to oral methylphenidate does not induce behavioral sensitization or cross-sensitization to nicotine

    Get PDF
    Several lines of evidence indicate that the use of stimulant drugs, including methylphenidate (MPD), increases tobacco smoking. This has raised concerns that MPD use during adolescence could facilitate nicotine abuse. Preclinical studies have shown that repeated treatment with an addictive drug produces sensitization to that drug and usually cross-sensitization to other drugs. Behavioral sensitization has been implicated in the development of drug addiction. We examined whether repeated oral MPD administration during adolescence could induce behavioral sensitization to MPD and long-lasting cross-sensitization to nicotine. Adolescent male Wistar rats were treated orally with 10 mg/kg MPD or saline (SAL) from postnatal day (PND) 27 to 33. To evaluate behavioral sensitization to MPD in adolescent rats (PND 39), the SAL pretreated group was subdivided into two groups that received intragastric SAL (1.0 mL/kg) or MPD (10 mg/kg); MPD pretreated rats received MPD (10 mg/kg). Cross-sensitization was evaluated on PND 39 or PND 70 (adulthood). To this end, SAL- and MPD-pretreated groups received subcutaneous injections of SAL (1.0 mL/kg) or nicotine (0.4 mg/kg). All groups had 8 animals. Immediately after injections, locomotor activity was determined. The locomotor response to MPD challenge of MPD-pretreated rats was not significantly different from that of the SAL-pretreated group. Moreover, the locomotor response of MPD-pretreated rats to nicotine challenge was not significantly different from that of the SAL-pretreated group. This lack of sensitization and cross-sensitization suggests that MPD treatment during adolescence does not induce short- or long-term neuroadaptation in rats that could increase sensitivity to MPD or nicotine

    Effects of diazoxide in experimental acute necrotizing pancreatitis

    Get PDF
    OBJECTIVE: We aimed to assess the effects of diazoxide on the mortality, pancreatic injury, and inflammatory response in an experimental model of acute pancreatitis. METHODS: Male Wistar rats (200-400 g) were divided randomly into two groups. Fifteen minutes before surgery, animals received physiological (0.9%) saline (3 mL/kg) (control group) or 45 mg/kg diazoxide (treatment group) via the intravenous route. Acute pancreatitis was induced by injection of 2.5% sodium taurocholate via the biliopancreatic duct. Mortality (n=38) was observed for 72 h and analyzed by the Mantel-Cox Log-rank test. To study pancreatic lesions and systemic inflammation, rats (10 from each group) were killed 3 h after acute pancreatitis induction; ascites volume was measured and blood as well as pancreases were collected. Pancreatic injury was assessed according to Schmidt’s scale. Cytokine expression in plasma was evaluated by the multiplex method. RESULTS: Mortality at 72 h was 33% in the control group and 60% in the treatment group (p=0.07). Ascites volumes and plasma levels of cytokines between groups were similar. No difference was observed in edema or infiltration of inflammatory cells in pancreatic tissues from either group. However, necrosis of acinar cells was lower in the treatment group compared to the control group (3.5 vs. 3.75, p=0.015). CONCLUSIONS: Treatment with diazoxide can reduce necrosis of acinar cells in an experimental model of acute pancreatitis, but does not affect the inflammatory response or mortality after 72 h

    Anomalous diffusion on crumpled wires in two dimensions

    Full text link
    It is investigated the statistical properties of random walks evolving on real configurations of a crumpled wire rigidly jammed in two dimensions. These crumpled hierarchical structures with complex topology are obtained from a metallic wire injected at a constant rate into a transparent planar cell of 20cm of diameter. The observed diffusion is anomalous with an exponent very close to that obtained at the threshold of two dimensional percolation. A comparison of the system studied in this paper with other systems of physical interest is also made, and an experimental consequence of our results is discussed.Comment: 10 pages including 4 figures. Physica A (2006). Preprin

    Urban Renewal and Industry Analysis

    Get PDF
    22 pagesThe overall goal of this course was to enhance the attractiveness of La Pine for its citizens, visitors, and businesses. This goal was broken into three primary projects focusing on Urban Renewal, industry viability, and workforce evaluation. The overall objective for the first project was to provide best practices for Urban Renewal processes in the short and long term. Short term recommendations include implementing a twelve-step Storefront Loan Program process and a two-phase minor enhancement project. Long term recommendations focus on implementing four best practices for large scale property transformation as well as creating a public art fund. Applying these recommendations to La Pine’s Urban Renewal plans can provide guidance and sustainability for future downtown development. The overall objective of the second project was to provide detailed industry benchmarking and rank the attractiveness of each industrial sector within La Pine. The teams recommend pursuing moderate- to high-potential industries including Wood Products Manufacturing, Food Processing, and Outdoor Gear and Apparel Manufacturing. The objective of the third project was to conduct a workforce asset analysis and recommend a ranking of industries where La Pine should focus its workforce development efforts. Based on their industry workforce assessment, the team recommends pursuing Specialty Foods Processing, Cross-Laminated Timber, and Cabinet Manufacturing. Both the second and third projects propose that La Pine pursue viable industries in alignment with the city’s workforce goals to ensure sustainable economic development

    Thermal computational model to predict thermal necrosis in bone sarcomas

    Get PDF
    Sarcomas are heterogeneous tumors that form frombonetissue, connective tissue, cartilaginous tissue,muscle tissue, adipose tissue, peripheral nerves, and blood vessels,usually atits extremities. These tumors occur at any age and in any region of the patient's body.info:eu-repo/semantics/publishedVersio

    Phytotoxicity and allelopathic potential of extracts from rhizomes and leaves of Arundo donax, an invasive grass in neotropical savannas

    Get PDF
    The perennial rhizomatous grass Arundo donax L. (Poaceae), the giant reed, is an exotic invasive species in several countries of Europe that is rapidly spreading in the savannas of Central Brazil, locally known as Cerrado. Allelopathy could facilitate the successful invasion of this species by hampering or suppressing the regeneration of the native vegetation. However, information on the phytotoxicity of A. donax extracts is limited.  We investigated the allelopathic potential of A. donax leaf and rhizome extracts, screened them for phytochemicals by thin-layer chromatography (TLC) and nuclear magnetic resonance (1H-NMR), and tested the extracts for antioxidant activity, antimicrobial activity, and cytotoxicity against Artemia salina. Aqueous and methanolic extracts were initially tested in germination and seedling growth bioassays using Lactuca sativa L. (Asteraceae). The aqueous extracts were then tested on five Cerrado tree species and on Megathyrsus maximus, an invasive, alien grass in the Cerrado. Extracts negatively affected germination and seedling growth of the target species. Leaf extracts were more inhibitory. Extracts did not show antioxidant and cytotoxic activity and had very low antimicrobial activity. Flavonoids, and other phenolics were detected mostly in leaves. Terpenes, which were also present in the leaves, were the main secondary metabolites in rhizomes. Alkaloids were detected by TLC in leaf methanolic extracts. However, 1H-NMR revealed the presence of indole alkaloids in methanolic extracts from rhizomes and leaves. We confirmed the allelopathic potential of this species and caution against weed control methods relying on cutting the plant back to soil level for favouring release of allelochemicals
    • …
    corecore