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Sample records for 63-day cure rates

  1. Relaxed Poisson cure rate models.

    PubMed

    Rodrigues, Josemar; Cordeiro, Gauss M; Cancho, Vicente G; Balakrishnan, N

    2016-03-01

    The purpose of this article is to make the standard promotion cure rate model (Yakovlev and Tsodikov, ) more flexible by assuming that the number of lesions or altered cells after a treatment follows a fractional Poisson distribution (Laskin, ). It is proved that the well-known Mittag-Leffler relaxation function (Berberan-Santos, ) is a simple way to obtain a new cure rate model that is a compromise between the promotion and geometric cure rate models allowing for superdispersion. So, the relaxed cure rate model developed here can be considered as a natural and less restrictive extension of the popular Poisson cure rate model at the cost of an additional parameter, but a competitor to negative-binomial cure rate models (Rodrigues et al., ). Some mathematical properties of a proper relaxed Poisson density are explored. A simulation study and an illustration of the proposed cure rate model from the Bayesian point of view are finally presented.

  2. Multiple imputation for cure rate quantile regression with censored data.

    PubMed

    Wu, Yuanshan; Yin, Guosheng

    2017-03-01

    The main challenge in the context of cure rate analysis is that one never knows whether censored subjects are cured or uncured, or whether they are susceptible or insusceptible to the event of interest. Considering the susceptible indicator as missing data, we propose a multiple imputation approach to cure rate quantile regression for censored data with a survival fraction. We develop an iterative algorithm to estimate the conditionally uncured probability for each subject. By utilizing this estimated probability and Bernoulli sample imputation, we can classify each subject as cured or uncured, and then employ the locally weighted method to estimate the quantile regression coefficients with only the uncured subjects. Repeating the imputation procedure multiple times and taking an average over the resultant estimators, we obtain consistent estimators for the quantile regression coefficients. Our approach relaxes the usual global linearity assumption, so that we can apply quantile regression to any particular quantile of interest. We establish asymptotic properties for the proposed estimators, including both consistency and asymptotic normality. We conduct simulation studies to assess the finite-sample performance of the proposed multiple imputation method and apply it to a lung cancer study as an illustration.

  3. Modeling the intracellular pathogen-immune interaction with cure rate

    NASA Astrophysics Data System (ADS)

    Dubey, Balram; Dubey, Preeti; Dubey, Uma S.

    2016-09-01

    Many common and emergent infectious diseases like Influenza, SARS, Hepatitis, Ebola etc. are caused by viral pathogens. These infections can be controlled or prevented by understanding the dynamics of pathogen-immune interaction in vivo. In this paper, interaction of pathogens with uninfected and infected cells in presence or absence of immune response are considered in four different cases. In the first case, the model considers the saturated nonlinear infection rate and linear cure rate without absorption of pathogens into uninfected cells and without immune response. The next model considers the effect of absorption of pathogens into uninfected cells while all other terms are same as in the first case. The third model incorporates innate immune response, humoral immune response and Cytotoxic T lymphocytes (CTL) mediated immune response with cure rate and without absorption of pathogens into uninfected cells. The last model is an extension of the third model in which the effect of absorption of pathogens into uninfected cells has been considered. Positivity and boundedness of solutions are established to ensure the well-posedness of the problem. It has been found that all the four models have two equilibria, namely, pathogen-free equilibrium point and pathogen-present equilibrium point. In each case, stability analysis of each equilibrium point is investigated. Pathogen-free equilibrium is globally asymptotically stable when basic reproduction number is less or equal to unity. This implies that control or prevention of infection is independent of initial concentration of uninfected cells, infected cells, pathogens and immune responses in the body. The proposed models show that introduction of immune response and cure rate strongly affects the stability behavior of the system. Further, on computing basic reproduction number, it has been found to be minimum for the fourth model vis-a-vis other models. The analytical findings of each model have been exemplified by

  4. Effect of rheological parameters on curing rate during NBR injection molding

    NASA Astrophysics Data System (ADS)

    Kyas, Kamil; Stanek, Michal; Manas, David; Skrobak, Adam

    2013-04-01

    In this work, non-isothermal injection molding process for NBR rubber mixture considering Isayev-Deng curing kinetic model, generalized Newtonian model with Carreau-WLF viscosity was modeled by using finite element method in order to understand the effect of volume flow rate, index of non-Newtonian behavior and relaxation time on the temperature profile and curing rate. It was found that for specific geometry and processing conditions, increase in relaxation time or in the index of non-Newtonian behavior increases the curing rate due to viscous dissipation taking place at the flow domain walls.

  5. Bayesian cure rate frailty models with application to a root canal therapy study.

    PubMed

    Yin, Guosheng

    2005-06-01

    Due to natural or artificial clustering, multivariate survival data often arise in biomedical studies, for example, a dental study involving multiple teeth from each subject. A certain proportion of subjects in the population who are not expected to experience the event of interest are considered to be "cured" or insusceptible. To model correlated or clustered failure time data incorporating a surviving fraction, we propose two forms of cure rate frailty models. One model naturally introduces frailty based on biological considerations while the other is motivated from the Cox proportional hazards frailty model. We formulate the likelihood functions based on piecewise constant hazards and derive the full conditional distributions for Gibbs sampling in the Bayesian paradigm. As opposed to the Cox frailty model, the proposed methods demonstrate great potential in modeling multivariate survival data with a cure fraction. We illustrate the cure rate frailty models with a root canal therapy data set.

  6. A cure-rate model for the Shuttle filament-wound case

    NASA Technical Reports Server (NTRS)

    Cagliostro, D. E.; Islas, A.; Hsu, Ming-Ta

    1987-01-01

    An epoxy and carbon fiber composite has been used to produce a light-weight rocket case for the Space Shuttle. A kinetic model is developed which can predict the extent of epoxy conversion during the winding and curing of the case. The model accounts for both chemical and physical kinetics. In the model, chemical kinetics occur exclusively up to the time the transition temperature equals the reaction temperature. At this point the resin begins to solidify and the rate of this process limits the rate of epoxy conversion. A comparison of predicted and actual epoxy conversion is presented for isothermal and temperature programmed cure schedules.

  7. Sample size calculation for testing differences between cure rates with the optimal log-rank test.

    PubMed

    Wu, Jianrong

    2017-01-01

    In this article, sample size calculations are developed for use when the main interest is in the differences between the cure rates of two groups. Following the work of Ewell and Ibrahim, the asymptotic distribution of the weighted log-rank test is derived under the local alternative. The optimal log-rank test under the proportional distributions alternative is discussed, and sample size formulas for the optimal and standard log-rank tests are derived. Simulation results show that the proposed formulas provide adequate sample size estimation for trial designs and that the optimal log-rank test is more efficient than the standard log-rank test, particularly when both cure rates and percentages of censoring are small.

  8. Expectation maximization-based likelihood inference for flexible cure rate models with Weibull lifetimes.

    PubMed

    Balakrishnan, Narayanaswamy; Pal, Suvra

    2016-08-01

    Recently, a flexible cure rate survival model has been developed by assuming the number of competing causes of the event of interest to follow the Conway-Maxwell-Poisson distribution. This model includes some of the well-known cure rate models discussed in the literature as special cases. Data obtained from cancer clinical trials are often right censored and expectation maximization algorithm can be used in this case to efficiently estimate the model parameters based on right censored data. In this paper, we consider the competing cause scenario and assuming the time-to-event to follow the Weibull distribution, we derive the necessary steps of the expectation maximization algorithm for estimating the parameters of different cure rate survival models. The standard errors of the maximum likelihood estimates are obtained by inverting the observed information matrix. The method of inference developed here is examined by means of an extensive Monte Carlo simulation study. Finally, we illustrate the proposed methodology with a real data on cancer recurrence.

  9. The destructive negative binomial cure rate model with a latent activation scheme.

    PubMed

    Cancho, Vicente G; Bandyopadhyay, Dipankar; Louzada, Francisco; Yiqi, Bao

    2013-07-01

    A new flexible cure rate survival model is developed where the initial number of competing causes of the event of interest (say lesions or altered cells) follow a compound negative binomial (NB) distribution. This model provides a realistic interpretation of the biological mechanism of the event of interest as it models a destructive process of the initial competing risk factors and records only the damaged portion of the original number of risk factors. Besides, it also accounts for the underlying mechanisms that leads to cure through various latent activation schemes. Our method of estimation exploits maximum likelihood (ML) tools. The methodology is illustrated on a real data set on malignant melanoma, and the finite sample behavior of parameter estimates are explored through simulation studies.

  10. Chemical approach for controlling nadimide cure temperature and rate with maleimide

    NASA Technical Reports Server (NTRS)

    Lauver, R. W. (Inventor)

    1985-01-01

    Polyimide resins suitable for use as composite matrix materials are formed by copolymerization of maleic and norbornenyl endcapped monomers and oligomers. The copolymers can be cured at temperatures under about 300 C by controlling the available concentration of the maleic end-capped reactant. Control can be achieved by adding sufficient amounts of said maleic reactant, or by chemical modification of either copolymers, so as to either increase Diels-Alder retrogression of the norbornenyl capped reactant and/or holding initiation and polymerization to a rate compatible with the availability of the maleic-capped reactant.

  11. Estimating the personal cure rate of cancer patients using population-based grouped cancer survival data.

    PubMed

    Binbing Yu; Tiwari, Ram C; Feuer, Eric J

    2011-06-01

    Cancer patients are subject to multiple competing risks of death and may die from causes other than the cancer diagnosed. The probability of not dying from the cancer diagnosed, which is one of the patients' main concerns, is sometimes called the 'personal cure' rate. Two approaches of modelling competing-risk survival data, namely the cause-specific hazards approach and the mixture model approach, have been used to model competing-risk survival data. In this article, we first show the connection and differences between crude cause-specific survival in the presence of other causes and net survival in the absence of other causes. The mixture survival model is extended to population-based grouped survival data to estimate the personal cure rate. Using the colorectal cancer survival data from the Surveillance, Epidemiology and End Results Programme, we estimate the probabilities of dying from colorectal cancer, heart disease, and other causes by age at diagnosis, race and American Joint Committee on Cancer stage.

  12. Hazard regression model and cure rate model in colon cancer relative survival trends: are they telling the same story?

    PubMed

    Bejan-Angoulvant, Theodora; Bouvier, Anne-Marie; Bossard, Nadine; Belot, Aurelien; Jooste, Valérie; Launoy, Guy; Remontet, Laurent

    2008-01-01

    Hazard regression models and cure rate models can be advantageously used in cancer relative survival analysis. We explored the advantages and limits of these two models in colon cancer and focused on the prognostic impact of the year of diagnosis on survival according to the TNM stage at diagnosis. The analysis concerned 9,998 patients from three French registries. In the hazard regression model, the baseline excess death hazard and the time-dependent effects of covariates were modelled using regression splines. The cure rate model estimated the proportion of 'cured' patients and the excess death hazard in 'non-cured' patients. The effects of year of diagnosis on these parameters were estimated for each TNM cancer stage. With the hazard regression model, the excess death hazard decreased significantly with more recent years of diagnoses (hazard ratio, HR 0.97 in stage III and 0.98 in stage IV, P < 0.001). In these advanced stages, this favourable effect was limited to the first years of follow-up. With the cure rate model, recent years of diagnoses were significantly associated with longer survivals in 'non-cured' patients with advanced stages (HR 0.95 in stage III and 0.97 in stage IV, P < 0.001) but had no significant effect on cure (odds ratio, OR 0.99 in stages III and IV, P > 0.5). The two models were complementary and concordant in estimating colon cancer survival and the effects of covariates. They provided two different points of view of the same phenomenon: recent years of diagnosis had a favourable effect on survival, but not on cure.

  13. Divergent selection on 63-day body weight in the rabbit: response on growth, carcass and muscle traits

    PubMed Central

    Larzul, Catherine; Gondret, Florence; Combes, Sylvie; de Rochambeau, Hubert

    2005-01-01

    The effects of selection for growth rate on weights and qualitative carcass and muscle traits were assessed by comparing two lines selected for live body weight at 63 days of age and a cryopreserved control population raised contemporaneously with generation 5 selected rabbits. The animals were divergently selected for five generations for either a high (H line) or a low (L line) body weight, based on their BLUP breeding value. Heritability (h2) was 0.22 for 63-d body weight (N = 4754). Growth performance and quantitative carcass traits in the C group were intermediate between the H and L lines (N = 390). Perirenal fat proportion (h2 = 0.64) and dressing out percentage (h2 = 0.55) ranked in the order L < H = C (from high to low). The weight and cross-sectional area of the Semitendinosus muscle, and the mean diameter of the constitutive myofibres were reduced in the L line only (N = 140). In the Longissimus muscle (N = 180), the ultimate pH (h2 = 0.16) and the maximum shear force reached in the Warner-Braztler test (h2 = 0.57) were slightly modified by selection. PMID:15588570

  14. Identifying Differences Between Biochemical Failure and Cure: Incidence Rates and Predictors

    SciTech Connect

    Vicini, Frank A.; Shah, Chirag; Kestin, Larry; Ghilezan, Mihai; Krauss, Daniel; Ye Hong; Brabbins, Donald; Martinez, Alvaro A.

    2011-11-15

    Background: Patients treated with radiation therapy (RT) for prostate cancer were evaluated to estimate the length of time required to document biochemical cure (BC) after treatment and the variables associated with long-term treatment efficacy. Patients and Methods: 2,100 patients received RT alone for localized prostate carcinoma (external-beam RT, n = 1,504; brachytherapy alone, n = 241; or brachytherapy + pelvic radiation, n = 355). The median external-beam dose was 68.4 Gy, and the median follow-up time was 8.6 years. Biochemical failure (BF) was defined according to the Phoenix definition. Results: Biochemical failure was experienced by 685 patients (32.6%). The median times to BF for low-, intermediate-, and high-risk groups were 6.0, 5.6, and 4.5 years respectively (p < 0.001). The average annual incidence rates of BF for years 1-5, 5-10,11-15, and 16-20 in low-risk patients were 2.0%, 2.0%, 0.3%, and 0.06% (p < 0.001); for intermediate-risk patients, 4%, 3%, 0.3%, and 0% (p < 0.001); and for high-risk patients, 10.0%, 5.0%, 0.3%, and 0.3% (p < 0.001). After 5 years of treatment, 36.9% of all patients experienced BF. The percentage of total failures occurring during years 1-5, 5-10, 11-15, and 16-20 were 48.7%, 43.5%, 6.5%, and 1.3% for low-risk patients; 64.0%, 32.2%, 3.8%, and 0% for intermediate-risk patients; and 71.9%, 25.9%, 1.1%, and 1.1% for high-risk patients, respectively. Increasing time to nadir was associated with increased time to BF. On multivariate analysis, factors significantly associated with 10-year BC included prostate-specific antigen nadir and time to nadir. Conclusions: The incidence rates for BF did not plateau until later than 10 years after treatment, suggesting that extended follow-up time is required to monitor patients after treatment. Prostate-specific antigen nadir and time to nadir have the strongest association with long-term BC.

  15. Optimal Composite Curing System

    NASA Astrophysics Data System (ADS)

    Handel, Paul; Guerin, Daniel

    The Optimal Composite Curing System (OCCS) is an intelligent control system which incorporates heat transfer and resin kinetic models coupled with expert knowledge. It controls the curing of epoxy impregnated composites, preventing part overheating while maintaining maximum cure heatup rate. This results in a significant reduction in total cure time over standard methods. The system uses a cure process model, operating in real-time, to determine optimal cure profiles for tool/part configurations of varying thermal characteristics. These profiles indicate the heating and cooling necessary to insure a complete cure of each part in the autoclave in the minimum amount of time. The system coordinates these profiles to determine an optimal cure profile for a batch of thermally variant parts. Using process specified rules for proper autoclave operation, OCCS automatically controls the cure process, implementing the prescribed cure while monitoring the operation of the autoclave equipment.

  16. The effect of intrauterine infusion of dextrose on clinical endometritis cure rate and reproductive performance of dairy cows.

    PubMed

    Machado, V S; Oikonomou, G; Ganda, E K; Stephens, L; Milhomem, M; Freitas, G L; Zinicola, M; Pearson, J; Wieland, M; Guard, C; Gilbert, R O; Bicalho, R C

    2015-06-01

    The main objective of this study was to evaluate the intrauterine administration use of 200 mL of 50% dextrose solution as a treatment against clinical endometritis (CE); CE cure rate and reproductive performance were evaluated. Additionally, the association of several relevant risk factors, such as retained placenta (RP), metritis, CE, anovulation, hyperketonemia, and body condition score with reproductive performance, early embryonic mortality, and CE were evaluated. A total of 1,313 Holstein cows housed on 4 commercial dairy farms were enrolled in the study. At 7±3 DIM cows were examined for metritis and had blood collected to determine serum β-hydroxybutyrate concentration. To determine if cows had ovulated at least once before 44±3 DIM, the presence of a corpus luteum was evaluated by ovarian ultrasonography at 30±3 DIM and at 44±3 DIM. At 30±3 DIM, CE was diagnosed using the Metricheck device (SimcroTech, Hamilton, New Zealand); cows with purulent or mucopurulent vaginal discharge were diagnosed as having CE. Cows diagnosed with CE (n=175) were randomly allocated into 2 treatment groups: treatment (intrauterine infusion of 200 mL of 50% dextrose) or control (no infusion). Clinical endometritis cows were re-evaluated as described above at 44±3 DIM, and cows that were free of purulent or mucopurulent vaginal discharge were considered cured. Intrauterine infusion of dextrose tended to have a detrimental effect on CE cure rate, and treatment did not have an effect on first-service conception rate and early embryonic mortality. A multivariable Cox's proportional hazard model was performed to evaluate the effect of several variables on reproductive performance; the variables RP, CE, parity, anovulation, and the interaction term between parity and anovulation were associated with hazard of pregnancy. Cows that did not have RP or CE were more likely to conceive than cows that were diagnosed with RP or CE. Cows that had RP were at 3.36 times higher odds of

  17. Sofalcone, a mucoprotective agent, increases the cure rate of Helicobacter pylori infection when combined with rabeprazole, amoxicillin and clarithromycin

    PubMed Central

    Isomoto, Hajime; Furusu, Hisashi; Ohnita, Ken; Wen, Chun-Yang; Inoue, Kenichiro; Kohno, Shigeru

    2005-01-01

    AIM: The mucoprotective agents, sofalcone and polaprezinc have anti-Helicobacter pylori (H pylori) activities. We determined the therapeutic effects of sofalcone and polaprezinc when combined with rabeprazole, amoxicillin and clarithromycin for Helicobacter pylori infection. METHODS: One hundred and sixty-five consecutive outpatients with peptic ulcer and H pylori infection were randomly assigned to one of the following three groups and medicated for 7 d. Group A: triple therapy with rabeprazole (10 mg twice daily), clarithromycin (200 mg twice daily) and amoxicillin (750 mg twice daily). Group B: sofalcone (100 mg thrice daily) plus the triple therapy. Group C: polaprezinc (150 mg twice daily) plus the triple therapy. Eradication was considered successful if 13C-urea breath test was negative at least 4 wk after cessation of eradication regimens or successive famotidine in the cases of active peptic ulcer. RESULTS: On intention-to-treat basis, H pylori cure was achieved in 43 of 55 (78.2%) patients, 47 of 54 (87.0%) and 45 of 56 (80.4%) for the groups A, B and C respectively. Using per protocol analysis, the eradication rates were 81.1% (43/53), 94.0% (47/50) and 84.9% (45/53) respectively. There was a significant difference in the cure rates between group A and B. Adverse events occurred in 10, 12 and 11 patients, from groups A, B and C respectively, but the events were generally mild. CONCLUSION: The addition of sofalcone, but not polaprezinc, significantly increased the cure rate of H pylori infection when combined with the rabeprazole-amoxicillin-clarithromycin regimen. PMID:15786539

  18. Cure rate is not a valid indicator for assessing drug efficacy and impact of preventive chemotherapy interventions against schistosomiasis and soil-transmitted helminthiasis.

    PubMed

    Montresor, Antonio

    2011-07-01

    Every year in endemic countries, several million individuals are given anthelminthic drugs in the context of preventive chemotherapy programmes for morbidity control of schistosomiasis and soil-transmitted helminthiasis. The capacity to evaluate accurately the efficacy of the drugs used as well as the health impact produced by treatment is of utmost importance for appropriate planning and implementation of these interventions. Cure rate is an indicator of drug efficacy that was originally developed for assessing the clinical efficacy of antibiotics on selected bacterial diseases. Over time, this indicator has also been widely applied to anthelminthic drugs and consequently used to monitor and evaluate preventive chemotherapy interventions. In the author's opinion, however, measurement of cure rate provides information of limited usefulness in the context of helminth control programmes. The present article analyses the peculiarities of helminth infections and those of the drugs used in preventive chemotherapy, explaining the reasons why the cure rate is not an adequate indicator in this specific public health context.

  19. Recurrence rate of stress urinary incontinence in females with initial cure after transobturator tape procedure at 3-year follow-up

    PubMed Central

    Jun, Taeyong; Yoon, Hyun Sik; Kim, Hyung Suk; Lee, Jeong Woo; Bae, Jungbum

    2017-01-01

    Purpose To assess recurrence rates of urinary incontinence in women with initial cure after transobturator tape (TOT) procedure at 3-year follow-up. Materials and Methods Between June 2006 and May 2013, a total of 402 consecutive patients underwent the TOT procedure for female stress urinary incontinence (SUI) at Dongguk University Ilsan Hospital. Of the 402 patients, 223 had sufficient medical records for analysis. Therefore, they were followed-up for 3 years postoperatively. Patient characteristics, urinary symptoms, physical examination, and urodynamic parameters were evaluated. The primary end point of “cure” was defined as the absence of any complaint of urinary leakage without needing pads for usual activities. Results Of the 223 patients, 196 patients (87.9%) were initially cured within 6 months postoperatively. Of the 196 patients, 70 (35.7%) had recurrent urinary incontinence at 3 years postoperatively, 51 (26.0%) had SUI, 16 (8.2%) had urgency urinary incontinence, and 3 (1.5%) had mixed urinary incontinence. In univariate analysis, preoperative urinary obstructive symptom was found to significant contributor to the recurrence of urinary incontinence at 3-year postoperatively (p=0.004). Conclusions In our study, 35.7% of the women with initial cure after TOT experienced the recurrence of urinary leakage during the 3-year follow-up. The cure rate of TOT was decreased as time went by, although the initial cure rate was high. PMID:28097269

  20. Cure SMA

    MedlinePlus

    ... the SMA drug pipeline. Together, we're making real progress toward a treatment and a cure. Latest ... Announce SPINRAZA (nusinersen) Meets Primary Endpoint at Interim Analysis of Phase 3 CHERISH Study Biogen and Ionis ...

  1. Effect of temperature-humidity index on live performance in broiler chickens grown from 49 to 63 days of age

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The thermal environment in poultry housing is a primary influence on production efficiency and live performance. Heavy broilers (body weight > 3.2 kg) typically require high ventilation rates to maintain thermal comfort and production efficiency. However, large birds are observed to pant in mild to ...

  2. SMS reminders to improve the tuberculosis cure rate in developing countries (TB-SMS Cameroon): a protocol of a randomised control study

    PubMed Central

    2014-01-01

    Background Tuberculosis is a public health problem in Cameroon, just like in many other countries in the world. The National Tuberculosis Control Programme (PNLT) put in place by the state, aims to fight tuberculosis through the implementation of international directives (Directly Observed Treatment Short, DOTS). Despite the deployment of this strategy across the world, its implementation is difficult in the context of low-resource countries. Some expected results are not achieved. In Cameroon, the cure rate for patients with sputum positive pulmonary tuberculosis (TPM+) after 6 months is only about 65%, 20% below the target. This is mainly due to poor patient adherence to treatment. By relying on the potential of mobile Health, the objective of this study is to evaluate the effect of SMS reminders on the cure rate of TPM + patients, measured using 6-month bacilloscopy. Methods/design This is a blinded, randomised controlled multicentre study carried out in Cameroon. The research hypothesis is that sending daily SMS messages to remind patients to take their prescribed tuberculosis medication, together with the standard DOTS strategy, will increase the cure rate from 65% (control group: DOTS, no SMS intervention) to 85% (intervention group: DOTS, with SMS intervention) in a group of new TPM + patients. In accordance with each treatment centre, the participants will be randomly allocated into the two groups using a computer program: the intervention group and the control group. A member of the research team will send daily SMS messages. Study data will be collected by health professionals involved in the care of patients. Data analysis will be done by the intention-to-treat method. Discussion The achieving of expected outcomes by the PNLT through implementation of DOTS requires several challenges. Although it has been demonstrated that the DOTS strategy is effective in the fight against tuberculosis, its application remains difficult in developing countries

  3. The influence of transmission season on parasitological cure rates and intensity of infection after praziquantel treatment of Schistosoma haematobium-infected schoolchildren in Mozambique.

    PubMed

    Augusto, G; Magnussen, P; Kristensen, T K; Appleton, C C; Vennervald, B J

    2009-11-01

    Schistosoma haematobium is refractory to praziquantel (PZQ) during the prepatent period of infection. A hypothesis based on this observation is that in areas where S. haematobium transmission is seasonal, the outcome of chemotherapy depends on the timing of the treatment relative to the annual transmission pattern. To examine this hypothesis, a study was carried out in southern Mozambique. Following demonstration of seasonal transmission, PZQ was administered separately to two cohorts of S. haematobium-infected schoolchildren in (1) the high and (2) the low transmission seasons and followed up after two months when levels of infection and intensities were measured. The prevalence of infection decreased from 54.2% and 51.7% in cohorts 1 and 2 to 30.3% and 1.8%, respectively. The geometric mean intensity of infection decreased from 23.3 eggs/10 ml of urine at baseline to 15.6 eggs/10 ml of urine in cohort 1 (treated during high transmission season), and from 23.5 eggs/10 ml urine to 7.3 eggs/10 ml of urine in cohort 2 (treated during low transmission season). The observed cure rates in cohorts 1 and 2 were 69.7% and 98.2%, respectively. Differences in infection between the cohorts in terms of cure rate and level of infection two months post-treatment were statistically significant and indicate that in areas with a seasonal transmission pattern, the effect of PZQ can be enhanced if treatment takes place during the low transmission season. We conclude that appropriately timed PZQ administration will increase the impact of schistosomiasis control programmes.

  4. A New Kind of Curing

    NASA Technical Reports Server (NTRS)

    2001-01-01

    A new curing method using automated tape placement (ATP) with electron beam (EB), or e-beam, produces a combination known as in situ e-beam curing. Through a Small Business Innovation Research (SBIR) contract from NASA's Marshall Space Flight Center, Science Research Laboratory, Inc., created the in situ e-beam curing technique, which uses a low-energy electron beam gun to cure various composite materials. One important benefit is the technique's utilization of room temperature curing, which lessens the chance of mismatching the thermal expansion coefficients of different materials. For instance, metals and composites will expand at different rates when heated, but the low-energy e-beam gun reduces the expansion differential. Using a low-energy gun also results in less x-ray shielding, significantly reduced capital costs, reduced facility space, and increased processing capabilities for larger parts. However, using a low-energy gun also means that each tape layer is treated individually because the gun can penetrate only one layer at a time. The e-beam gun emits lower energy x-rays, which are more easily shielded than those emitted by previous guns. The low-energy system is relatively portable due to its light weight and small size. The gun weighs about 70 pounds and can be easily mounted on a robotic arm or an ATP head.

  5. Assessing the prediction accuracy of cure in the Cox proportional hazards cure model: an application to breast cancer data.

    PubMed

    Asano, Junichi; Hirakawa, Akihiro; Hamada, Chikuma

    2014-01-01

    A cure rate model is a survival model incorporating the cure rate with the assumption that the population contains both uncured and cured individuals. It is a powerful statistical tool for prognostic studies, especially in cancer. The cure rate is important for making treatment decisions in clinical practice. The proportional hazards (PH) cure model can predict the cure rate for each patient. This contains a logistic regression component for the cure rate and a Cox regression component to estimate the hazard for uncured patients. A measure for quantifying the predictive accuracy of the cure rate estimated by the Cox PH cure model is required, as there has been a lack of previous research in this area. We used the Cox PH cure model for the breast cancer data; however, the area under the receiver operating characteristic curve (AUC) could not be estimated because many patients were censored. In this study, we used imputation-based AUCs to assess the predictive accuracy of the cure rate from the PH cure model. We examined the precision of these AUCs using simulation studies. The results demonstrated that the imputation-based AUCs were estimable and their biases were negligibly small in many cases, although ordinary AUC could not be estimated. Additionally, we introduced the bias-correction method of imputation-based AUCs and found that the bias-corrected estimate successfully compensated the overestimation in the simulation studies. We also illustrated the estimation of the imputation-based AUCs using breast cancer data.

  6. Radiation curing of epoxies

    NASA Astrophysics Data System (ADS)

    Dickson, Lawrence W.; Singh, Ajit

    The literature on radiation polymerization of epoxy compounds has been reviewed to assess the potential use of radiation for curing these industrially important monomers. Chemical curing of epoxies may proceed by either cationic or anionic mechanisms depending on the nature of the curing agent, but most epoxies polymerize by cationic mechanisms under the influence of high-energy radiation. Radiation-induced cationic polymerization of epoxy compounds is inhibited by trace quantities of water because of proton transfer from the chain-propagating epoxy cation to water. Several different methods with potential for obtaining high molecular weight polymers by curing epoxies with high-energy radiation have been studied. Polymeric products with epoxy-like properties have been produced by radiation curing of epoxy oligomers with terminal acrylate groups and mixtures of epoxies with vinyl monomers. Both of these types of resin have good potential for industrial-scale curing by radiation treatment.

  7. Intraoperative radiation therapy in patients with bladder cancer. A review of techniques allowing improved tumor doses and providing high cure rates without loss of bladder function

    SciTech Connect

    Shipley, W.U.; Kaufman, S.D.; Prout, G.R. Jr.

    1987-10-01

    Conventional external beam irradiation, using modern megavoltage techniques and doses that do not harm bladder function, will permanently eradicate local bladder cancer in 30% to 50% of patients, compared with 70% to 90% with cystectomy. In appropriately chosen patients, open surgery can safely provide excellent exposure for the selective delivery of more radiant energy directly to the tumor and less to the uninvolved portion of the bladder. Intraoperative radiation therapy, by either a removable radium or iridium implant or a large single dose of electrons, has been reported to be safe and can permanently cure the bladder of cancer and also preserve bladder function in more than 75% of patients with solitary tumors that invade into but not beyond the bladder muscle. With the increasing interest in and availability of intraoperative radiation therapy in the US, this curative and bladder-sparing treatment for operable patients with bladder cancer invading the trigone is appropriate for careful clinical trial. 13 references.

  8. Multivariate curve resolution-alternating least squares and kinetic modeling applied to near-infrared data from curing reactions of epoxy resins: mechanistic approach and estimation of kinetic rate constants.

    PubMed

    Garrido, M; Larrechi, M S; Rius, F X

    2006-02-01

    This study describes the combination of multivariate curve resolution-alternating least squares with a kinetic modeling strategy for obtaining the kinetic rate constants of a curing reaction of epoxy resins. The reaction between phenyl glycidyl ether and aniline is monitored by near-infrared spectroscopy under isothermal conditions for several initial molar ratios of the reagents. The data for all experiments, arranged in a column-wise augmented data matrix, are analyzed using multivariate curve resolution-alternating least squares. The concentration profiles recovered are fitted to a chemical model proposed for the reaction. The selection of the kinetic model is assisted by the information contained in the recovered concentration profiles. The nonlinear fitting provides the kinetic rate constants. The optimized rate constants are in agreement with values reported in the literature.

  9. Measuring Vapors To Monitor the State of Cure of a Resin

    NASA Technical Reports Server (NTRS)

    Cramer, Elliott; Perey, Daniel F.; Yost, William T.

    2006-01-01

    A proposed noninvasive method of monitoring the cure path and the state of cure of an epoxy or other resin involves measurement of the concentration( s) of one or more compound(s) in the vaporous effluent emitted during the curing process. The method is based on the following general ideas: (1) The concentrations of the effluent compounds in the vicinity of the curing resin are approximately proportional to the instantaneous rate of curing. (2) As curing proceeds at a given temperature, subsequent decreases in the concentrations are indicative of approaching completion of cure; that is, the lower are the concentrations, the more nearly complete is the cure.

  10. Can liver transplantation provide the statistical cure?

    PubMed

    Cucchetti, Alessandro; Vitale, Alessandro; Cescon, Matteo; Gambato, Martina; Maroni, Lorenzo; Ravaioli, Matteo; Ercolani, Giorgio; Burra, Patrizia; Cillo, Umberto; Pinna, Antonio D

    2014-02-01

    Liver transplantation (LT) represents the only chance of long-term survival for patients with end-stage liver disease. When the mortality rate for transplant patients returns to the same level as that for the general population, they can be considered statistically cured. However, cure models in the setting of LT have never been applied. Data from 1371 adult patients undergoing LT for the first time between January 1999 and December 2012 at 2 Italian centers were reviewed in order to establish probabilities of being cured by LT. A parametric Weibull model was applied to compare the mortality rate after LT to the rate expected for the general population (matched by sex and age). The observed 3-, 5-, and 10-year overall survival rates after LT were 77.8%, 73.3%, and 65.6%, respectively, and they did not differ between the 2 centers (P = 0.37). The cure fraction for the entire study population was 63.4% (95% confidence interval = 52.6%-72.0%), and the time to cure was 10 years with a 90% confidence level. The best cure fraction was observed for younger recipients without hepatitis C virus (HCV) who had favorable donor-recipient matches, that is, low Donor Model for End-Stage Liver Disease (D-MELD) scores (90.1%); conversely, the lowest probability was observed for elderly HCV recipients with high D-MELD scores (34.6%). The time to cure was 6.22 years for non-HCV patients and 14.78 years for HCV patients. The median survival time for uncured patients was 2.29 years. Among uncured recipients, the longest survival time was observed for younger patients (7.31 years). In conclusion, we provide here a new clinical measure for LT suggesting that survival after transplantation can approximate that of the general population and provide a statistical cure.

  11. Nothing a Hot Bath Won't Cure: Infection Rates of Amphibian Chytrid Fungus Correlate Negatively with Water Temperature under Natural Field Settings

    PubMed Central

    2011-01-01

    Dramatic declines and extinctions of amphibian populations throughout the world have been associated with chytridiomycosis, an infectious disease caused by the pathogenic chytrid fungus Batrachochytrium dendrobatidis (Bd). Previous studies indicated that Bd prevalence correlates with cooler temperatures in the field, and laboratory experiments have demonstrated that Bd ceases growth at temperatures above 28°C. Here we investigate how small-scale variations in water temperature correlate with Bd prevalence in the wild. We sampled 221 amphibians, including 201 lowland leopard frogs (Rana [Lithobates] yavapaiensis), from 12 sites in Arizona, USA, and tested them for Bd. Amphibians were encountered in microhabitats that exhibited a wide range of water temperatures (10–50°C), including several geothermal water sources. There was a strong inverse correlation between the water temperature in which lowland leopard frogs were captured and Bd prevalence, even after taking into account the influence of year, season, and host size. In locations where Bd was known to be present, the prevalence of Bd infections dropped from 75–100% in water <15°C, to less than 10% in water >30°C. A strong inverse correlation between Bd infection status and water temperature was also observed within sites. Our findings suggest that microhabitats where water temperatures exceed 30°C provide lowland leopard frogs with significant protection from Bd, which could have important implications for disease dynamics, as well as management applications. There must be quite a few things a hot bath won't cure, but I don't know many of them - Sylvia Plath, “The Bell Jar” (1963). PMID:22205950

  12. Nothing a hot bath won't cure: infection rates of amphibian chytrid fungus correlate negatively with water temperature under natural field settings.

    PubMed

    Forrest, Matthew J; Schlaepfer, Martin A

    2011-01-01

    Dramatic declines and extinctions of amphibian populations throughout the world have been associated with chytridiomycosis, an infectious disease caused by the pathogenic chytrid fungus Batrachochytrium dendrobatidis (Bd). Previous studies indicated that Bd prevalence correlates with cooler temperatures in the field, and laboratory experiments have demonstrated that Bd ceases growth at temperatures above 28°C. Here we investigate how small-scale variations in water temperature correlate with Bd prevalence in the wild. We sampled 221 amphibians, including 201 lowland leopard frogs (Rana [Lithobates] yavapaiensis), from 12 sites in Arizona, USA, and tested them for Bd. Amphibians were encountered in microhabitats that exhibited a wide range of water temperatures (10-50°C), including several geothermal water sources. There was a strong inverse correlation between the water temperature in which lowland leopard frogs were captured and Bd prevalence, even after taking into account the influence of year, season, and host size. In locations where Bd was known to be present, the prevalence of Bd infections dropped from 75-100% in water <15°C, to less than 10% in water >30°C. A strong inverse correlation between Bd infection status and water temperature was also observed within sites. Our findings suggest that microhabitats where water temperatures exceed 30°C provide lowland leopard frogs with significant protection from Bd, which could have important implications for disease dynamics, as well as management applications.There must be quite a few things a hot bath won't cure, but I don't know many of them--Sylvia Plath, "The Bell Jar" (1963).

  13. Fast Curing of Composite Wood Products

    SciTech Connect

    Dr. Arthur J. Ragauskas

    2006-04-26

    The overall objective of this program is to develop low temperature curing technologies for UF and PF resins. This will be accomplished by: • Identifying the rate limiting UF and PF curing reactions for current market resins; • Developing new catalysts to accelerate curing reactions at reduced press temperatures and times. In summary, these new curing technologies will improve the strength properties of the composite wood products and minimize the detrimental effects of wood extractives on the final product while significantly reducing energy costs for wood composites. This study is related to the accelerated curing of resins for wood composites such as medium density fiberboard (MDF), particle board (PB) and oriented strandboard (OSB). The latter is frequently manufactured with a phenol-formaldehyde resin whereas ureaformaldehyde (UF) resins are usually used in for the former two grades of composite wood products. One of the reasons that hinder wider use of these resins in the manufacturing of wood composites is the slow curing speed as well as inferior bondability of UF resin. The fast curing of UP and PF resins has been identified as an attractive process development that would allow wood to be bonded at higher moisture contents and at lower press temperatures that currently employed. Several differing additives have been developed to enhance cure rates of PF resins including the use of organic esters, lactones and organic carbonates. A model compound study by Conner, Lorenz and Hirth (2002) employed 2- and 4-hydroxymethylphenol with organic esters to examine the chemical basis for the reported enhanced reactivity. Their studies suggested that the enhance curing in the presence of esters could be due to enhanced quinone methide formation or enhanced intermolecular SN2 reactions. In either case the esters do not function as true catalysts as they are consumed in the reaction and were not found to be incorporated in the polymerized resin product. An

  14. Thermal rheological analysis of cure process of epoxy prepreg

    NASA Astrophysics Data System (ADS)

    Sun, Liangfeng

    2002-01-01

    The cure process of epoxy prepreg used as composite pipe joints was studied by means of differential scanning calorimetry (DSC), Bohlin Rheometer and other techniques. Isothermal DSC measurements were conducted between 110 and 220°C, at 10°C intervals. The results show that the complete cure reaction could be achieved at 220°C. The isothermal cure process was simulated with the four-parameter autocatalytic model. Except in the late stage of cure reaction, the model agrees well with the experimental data, especially at high temperatures. To account for the effect of diffusion on the cure rate, a diffusion factor was introduced into the model. The modified model greatly improved the predicated data at the late stage of cure reaction. The dynamic cure process was different from the isothermal cure process in that it is composed of two cure reactions. For dynamic cure process, a three-parameter autocatalytic model was used. The parameters in the model were determined by two methods. One was based on Kissinger and Ozawa approach. The whole curing process was modeled with two reactions. Another method was based on Borchardt and Daniels kinetic approach with whole curing process was modeled with one reaction. The fitting results by first and second method agreed well with experimental value in the late and early cure stage, separately. Rheological properties of epoxy prepreg are closely related to the cure process. With the development of cure reaction, gelation occurs and epoxy prepreg becomes difficult to process. As temperature increases, the gel time decreases. Viscosity profiles were described by different models. Except the first and nth order viscosity models, new viscosity models were proposed. The proposed new viscosity models are better than the old models for both isothermal and dynamic cure processes. To graphically represent the phase changes of the cure process, the isothermal cure diagrams of time-temperature-transformation (TTT) and conversion

  15. High cure rates in Burkitt lymphoma and leukemia: a Northern Italy Leukemia Group study of the German short intensive rituximab-chemotherapy program.

    PubMed

    Intermesoli, Tamara; Rambaldi, Alessandro; Rossi, Giuseppe; Delaini, Federica; Romani, Claudio; Pogliani, Enrico Maria; Pagani, Chiara; Angelucci, Emanuele; Terruzzi, Elisabetta; Levis, Alessandro; Cassibba, Vincenzo; Mattei, Daniele; Gianfaldoni, Giacomo; Scattolin, Anna Maria; Di Bona, Eros; Oldani, Elena; Parolini, Margherita; Gökbuget, Nicola; Bassan, Renato

    2013-11-01

    We evaluate the long-term results of a prospective clinical study enrolling more than 100 adult patients with Burkitt lymphoma/leukemia. Depending on extent of disease, treatment consisted of six to eight rituximab infusions and four to six courses of intensive chemotherapy (attenuated in patients aged >55 years) with high-dose methotrexate, fractionated ifosfamide/cyclophosphamide, other drugs in rotation, and intrathecal chemoprophylaxis. One-hundred five patients were treated (median age 47 years, range 17-78 years); 48% had Burkitt leukemia, 25% were older than 60 years, 37% had an Eastern Cooperative Oncology Group performance score >1, and 14% were positive for human immunodeficiency virus. The complete response rate and 3-year overall and disease-free survival rates were 79%, 67% and 75%, respectively, ranging from 100% to 45% for survival (P=0.000) and from 100% to 60% for disease-free survival (P=0.01) in patients with low, intermediate and high adapted International Prognostic Index scores. In multivariate analysis, only age (≤ versus >60 years) and performance status (0-1 versus >1) retained prognostic significance, identifying three risk groups with overall and disease-free survival probabilities of 88% and 87.5%, 57% and 70.5%, 20% and 28.5% (P=0.0000 and P=0.0001), respectively. The relapse rate was only 7% in patients treated with an intercycle interval ≤ 25 days. This regimen achieved 100% curability in patients with low adapted International Prognostic Index scores (21% of total), and very close to 90% in patients aged ≤ 60 years with performance score 0-1 (48% of total). Rapid diagnosis of Burkitt lymphoma/leukemia with prompt referral of patients to prevent clinical deterioration, and careful supervision of treatment without chemotherapy delay can achieve outstanding therapeutic results. ClinicalTrials.gov ID, NCT01290120.

  16. Estimating and modeling the cure fraction in population-based cancer survival analysis.

    PubMed

    Lambert, Paul C; Thompson, John R; Weston, Claire L; Dickman, Paul W

    2007-07-01

    In population-based cancer studies, cure is said to occur when the mortality (hazard) rate in the diseased group of individuals returns to the same level as that expected in the general population. The cure fraction (the proportion of patients cured of disease) is of interest to patients and is a useful measure to monitor trends in survival of curable disease. There are 2 main types of cure fraction model, the mixture cure fraction model and the non-mixture cure fraction model, with most previous work concentrating on the mixture cure fraction model. In this paper, we extend the parametric non-mixture cure fraction model to incorporate background mortality, thus providing estimates of the cure fraction in population-based cancer studies. We compare the estimates of relative survival and the cure fraction between the 2 types of model and also investigate the importance of modeling the ancillary parameters in the selected parametric distribution for both types of model.

  17. Process for curing bismaleimide resins

    NASA Technical Reports Server (NTRS)

    Parker, John A. (Inventor); OTHY S.imides alone. (Inventor)

    1986-01-01

    This invention relates to vinyl pyridine group containing compounds and oligomers, their advantageous copolymerization with bismaleimide resins, and the formation of reinforced composites based on these copolymers. When vinyl pyridines including vinyl stilbazole materials and vinyl styrylpyridine oligomer materials are admixed with bismaleimides and cured to form copolymers the cure temperatures of the copolymers are substantially below the cure temperatures of the bismaleimides alone.

  18. New addition curing polyimides

    NASA Technical Reports Server (NTRS)

    Frimer, Aryeh A.; Cavano, Paul

    1991-01-01

    In an attempt to improve the thermal-oxidative stability (TOS) of PMR-type polymers, the use of 1,4-phenylenebis (phenylmaleic anhydride) PPMA, was evaluated. Two series of nadic end-capped addition curing polyimides were prepared by imidizing PPMA with either 4,4'-methylene dianiline or p-phenylenediamine. The first resulted in improved solubility and increased resin flow while the latter yielded a compression molded neat resin sample with a T(sub g) of 408 C, close to 70 C higher than PME-15. The performance of these materials in long term weight loss studies was below that of PMR-15, independent of post-cure conditions. These results can be rationalized in terms of the thermal lability of the pendant phenyl groups and the incomplete imidization of the sterically congested PPMA. The preparation of model compounds as well as future research directions are discussed.

  19. Cure behavior of epoxy polymers used in microelectronics

    NASA Astrophysics Data System (ADS)

    Taweeplengsangsuke, Jantrawan

    2000-10-01

    Underfill resins are used to reduce solder fatigue in flip-chip assemblies. Both underfilling and curing processes are critical to achieve reliable finished products. This study included two main themes; the development of processing diagrams for commercial underfill resins and the fundamental understanding of cure kinetics and evolution of cure stresses in model epoxies. A variety of techniques have been used to characterize the fundamental phenomena involved in the processing of underfill resins. The flow behavior, cure kinetics, cure stresses, outgassing phenomena and void formation of underfill resins were studied. Processing diagrams for underfill resins were developed by mapping fundamental phenomena involved to provide a guideline for underfilling and curing steps. With these processing diagrams one should be able to design his underfilling and curing process with scientific approach. Two commercial underfill resins, which were evaluated as part of a SEMATECH program, where shown to possess significantly different processing characteristics. However, the appropriate explanation could not be made without knowing the proprietary chemistry of the systems. Therefore, model epoxies were formulated. Three different systems were investigated; amine, imidazole, and anhydride curing agent systems. With the known chemistry, the reaction kinetics and developed cure stress can be explained more clearly. Vitrification, which severely retards the rate of reaction, was found in amine (N-aminoethylpiperazine) and anhydride (Hexahydro-4-methylphthalic anhydride) cured systems when the cure temperatures were lower than the glass transition temperature (T g) of fully cured samples; however, imidazole(2-ethyl-4-methyl-imidazole) did not show vitrification when it was cured at 20 degrees below the T g of fully cured sample due to the large exotherms. Interestingly for imidazole system, the higher cure temperature exhibited a lower Tg. This could possibly be explained by the

  20. The research of UV curing injection molding

    NASA Astrophysics Data System (ADS)

    Xie, Pengcheng; Chang, Le; Song, Le; Cai, Tianze; Ding, Yumei; Yang, Weimin

    2015-05-01

    The micro-injection molding technology and the UV (ultraviolet) curing technique are combined to bring about a new plastic forming method, UV curing injection molding. The mean weight of micro-product is an important process characteristic for UV curing injection molding as well as the surface quality of micro-features is another important process characteristic for this new plastic forming method. This research investigates three effects of processing factors on the mass-change rate of micro-product and the surface quality of micro-features. In every particular, the following two factors are considered: UV material system temperature and the packing pressure. The study revealed that as usual, the micro-products gain weight with the imported increasing UV material system temperature and the improved packing pressure. Meanwhile, the increasing packing pressure also improves the surface quality, yet, warming the UV system temperature up has no effect on the quality of the product.

  1. Why cure, why now?

    PubMed Central

    Kuritzkes, Daniel R

    2017-01-01

    Combination antiretroviral therapy (cART) is highly effective at preventing morbidity and mortality due to infection with human immunodeficiency virus (HIV), but does not eradicate the virus. Consequently, cART must be administered life-long. Recent progress has stimulated research towards a cure of HIV infection. Approaches under investigation include hematopoietic stem cell transplantation, latency reactivating agents, immune based therapies, and cell-based therapies. Each of these approaches carries potential risks that must be weighed against the availability of safe and effective cART. Balancing the risks and benefits of this research poses unique challenges to potential study participants, clinicians and investigators. PMID:27273887

  2. Curing system for high voltage cross linked cables

    DOEpatents

    Bahder, George; Katz, Carlos; Bopp, Louis A.

    1978-01-01

    This invention makes extruded, vulcanized, high voltage cables insulated with thermosetting compounds at much higher rates of production and with superior insulation of reduced thickness and with reduced cavities or voids in the insulation. As the cable comes from an extruder, it passes into a curing chamber with a heat booster that quickly raises the insulation to a temperature at which it is cured much more quickly than with steam heating of the prior art. A high temperature liquid in contact with the insulation maintains the high temperature; and because of the greater curing heat, the cable can travel through the curing chamber at a faster rate and into a cooling tube where it contacts with a cooling liquid under high pressure. The insulation compound is treated to reduce the size of cavities; and the high pressure maintained by the curing and cooling mediums prevent expansion of cavities before the insulation is set.

  3. The Lourdes Medical Cures Revisited†

    PubMed Central

    François, Bernard; Sternberg, Esther M.; Fee, Elizabeth

    2014-01-01

    This article examines the cures recorded in Lourdes, France, between 1858, the year of the Visions, and 1976, the date of the last certified cure of the twentieth century. Initially, the records of cures were crude or nonexistent, and allegations of cures were accepted without question. A Medical Bureau was established in 1883 to examine and certify the cures, and the medical methodology improved steadily in the subsequent years. We discuss the clinical criteria of the cures and the reliability of medical records. Some 1,200 cures were said to have been observed between 1858 and 1889, and about one hundred more each year during the “Golden Age” of Lourdes, 1890–1914. We studied 411 patients cured in 1909–14 and thoroughly reviewed the twenty-five cures acknowledged between 1947 and 1976. No cure has been certified from 1976 through 2006. The Lourdes phenomenon, extraordinary in many respects, still awaits scientific explanation. Lourdes concerns science as well as religion. PMID:22843835

  4. Effectiveness of Membrane-Forming Curing Compounds for Curing Concrete

    DTIC Science & Technology

    1990-04-01

    Type I portland cement designated WES-48, C-I and a graded silica sand from Ottawa, IL, C-109, was used in preparing the mortar for testing. The test...report for the portland cement is shown in Table 1. Membrane-Forming Curing Compounds 6. Nine curing compounds obtained from four manufacturers were...evaluating the effectiveness of cure of portland - cement mortar were investigated that included: water absorptivity at different depths, capillary porosity

  5. Comparative static curing versus dynamic curing on tablet coating structures.

    PubMed

    Gendre, Claire; Genty, Muriel; Fayard, Barbara; Tfayli, Ali; Boiret, Mathieu; Lecoq, Olivier; Baron, Michel; Chaminade, Pierre; Péan, Jean Manuel

    2013-09-10

    Curing is generally required to stabilize film coating from aqueous polymer dispersion. This post-coating drying step is traditionally carried out in static conditions, requiring the transfer of solid dosage forms to an oven. But, curing operation performed directly inside the coating equipment stands for an attractive industrial application. Recently, the use of various advanced physico-chemical characterization techniques i.e., X-ray micro-computed tomography, vibrational spectroscopies (near infrared and Raman) and X-ray microdiffraction, allowed new insights into the film-coating structures of dynamically cured tablets. Dynamic curing end-point was efficiently determined after 4h. The aim of the present work was to elucidate the influence of curing conditions on film-coating structures. Results demonstrated that 24h of static curing and 4h of dynamic curing, both performed at 60°C and ambient relative humidity, led to similar coating layers in terms of drug release properties, porosity, water content, structural rearrangement of polymer chains and crystalline distribution. Furthermore, X-ray microdiffraction measurements pointed out different crystalline coating compositions depending on sample storage time. An aging mechanism might have occur during storage, resulting in the crystallization and the upward migration of cetyl alcohol, coupled to the downward migration of crystalline sodium lauryl sulfate within the coating layer. Interestingly, this new study clearly provided further knowledge into film-coating structures after a curing step and confirmed that curing operation could be performed in dynamic conditions.

  6. Estimation of Cure Fraction for Lognormal Right Censored Data with Covariates

    NASA Astrophysics Data System (ADS)

    Taweab, Fauzia Ali; Ibrahim, Noor Akma; Aljawadi, Bader Ahmad I.

    In clinical studies, a proportion of patients might be unsusceptible to the event of interest and can be considered as cured. The survival models that incorporate the cured proportion are known as cure rate models where the most widely used model is the mixture cure model. However, in cancer clinical trials, mixture model is not the appropriate model and the viable alternative is the Bounded Cumulative Hazard (BCH) model. In this paper we consider the BCH model to estimate the cure fraction based on the lognormal distribution. The parametric estimation of the cure fraction for survival data with right censoring with covariates is obtained by using EM algorithm.

  7. Modeling HIV Cure

    NASA Astrophysics Data System (ADS)

    Perelson, Alan; Conway, Jessica; Cao, Youfang

    A large effort is being made to find a means to cure HIV infection. I will present a dynamical model of post-treatment control (PTC) or ``functional cure'' of HIV-infection. Some patients treated with suppressive antiviral therapy have been taken off of therapy and then spontaneously control HIV infection such that the amount of virus in the circulation is maintained undetectable by clinical assays for years. The model explains PTC occurring in some patients by having a parameter regime in which the model exhibits bistability, with both a low and high steady state viral load being stable. The model makes a number of predictions about how to attain the low PTC steady state. Bistability in this model depends upon the immune response becoming exhausted when over stimulated. I will also present a generalization of the model in which immunotherapy can be used to reverse immune exhaustion and compare model predictions with experiments in SIV infected macaques given immunotherapy and then taken off of antiretroviral therapy. Lastly, if time permits, I will discuss one of the hurdles to true HIV eradication, latently infected cells, and present clinical trial data and a new model addressing pharmacological means of flushing out the latent reservoir. Supported by NIH Grants AI028433 and OD011095.

  8. [Towards the definition of cure].

    PubMed

    Touzet, Patrick

    Is the term cure adapted to psychiatry? Firstly, it is important to establish what this status represents. What is immediately clear is that the term cure cannot be addressed in isolation. Considering the term leads us to question notions such as those of disease and the norm, without forgetting the actual purpose of care. Cure can then be envisaged more as a 'possible' for caregivers.

  9. Dielectric cure monitoring: Preliminary studies

    NASA Technical Reports Server (NTRS)

    Goldberg, B. E.; Semmel, M. L.

    1984-01-01

    Preliminary studies have been conducted on two types of dielectric cure monitoring systems employing both epoxy resins and phenolic composites. An Audrey System was used for 23 cure monitoring runs with very limited success. Nine complete cure monitoring runs have been investigated using a Micromet System. Two additional measurements were performed to investigate the Micromet's sensitivity to water absorption in a post-cure carbon-phenolic material. While further work is needed to determine data significance, the Micromet system appears to show promise as a feedback control device during processing.

  10. Delayed cure bismaleimide resins

    DOEpatents

    Adams, Johnnie E.; Jamieson, Donald R.

    1984-08-07

    Polybismaleimides prepared by delayed curing of bis-imides having the formula ##STR1## wherein R.sub.1 and R.sub.2 each independently is H, C.sub.1-4 -alkyl, C.sub.1-4 -alkoxy, Cl or Br, or R.sub.1 and R.sub.2 together form a fused 6-membered hydrocarbon aromatic ring, with the proviso that R.sub.1 and R.sub.2 are not t-butyl or t-butoxy; X is O, S or Se; n is 1-3; and the --(CH.sub.2).sub.n -- group, optionally, is substituted by 1-3 methyl groups or by fluorine.

  11. Ionizing radiation post-curing of objects produced by stereolithography and other methods

    DOEpatents

    Howell, David H.; Eberle, Claude C.; Janke, Christopher J.

    2000-01-01

    An object comprised of a curable material and formed by stereolithography or another three-dimensional prototyping method, in which the object has undergone initial curing, is subjected to post-curing by ionizing radiation, such as an electron beam having a predetermined beam output energy, which is applied in a predetermined dosage and at a predetermined dose rate. The post-cured object exhibits a property profile which is superior to that which existed prior to the ionizing radiation post-curing.

  12. Ambient curing fire resistant foams

    NASA Technical Reports Server (NTRS)

    Hamermesh, C. L.; Hogenson, P. A.; Tung, C. Y.; Sawko, P. M.; Riccitiello, S. R.

    1979-01-01

    The feasibility of development of an ambient curing foam is described. The thermal stability and flame spread index of the foams were found to be comparable to those of the high-temperature cured polyimide foams by Monsanto two-foot tunnel test and NASA T-3 Fire test. Adaptation of the material to spray in place applications is described

  13. Cure of incurable lymphoma

    SciTech Connect

    De Nardo, Gerald L.

    2006-10-01

    The most potent method for augmenting the cytocidal power of monoclonal antibody (MAb) treatment is to conjugate radionuclides to the MAb to deliver systemic radiotherapy (radioimmunotherapy; RIT). The antigen, MAb, and its epitope can make a difference in the performance of the drug. Additionally, the radionuclide, radiochemistry, chelator for radiometals and the linker between the MAb and chelator can have a major influence on the performance of drugs (radiopharmaceuticals) for RIT. Smaller radionuclide carriers, such as antibody fragments and mimics, and those used for pretargeting strategies, have been described and evaluated. All of these changes in the drugs and strategies for RIT have documented potential for improved performance and patient outcomes. RIT is a promising new therapy that should be incorporated into the management of patients with B-cell non-Hodgkin's lymphoma (NHL) soon after these patients have proven incurable. Predictable improvements using better drugs, strategies, and combinations with other drugs seem certain to make RIT integral to the management of patients with NHL, and likely lead to cure of currently incurable NHL.

  14. Definitive evidence for hypoxic cells influencing cure in cancer therapy.

    PubMed

    Bush, R S; Jenkin, R D; Allt, W E; Beale, F A; Bean, H; Dembo, A J; Pringle, J F

    1978-06-01

    From an analysis of 2803 patients with carcinoma of the cervix treated by radiation therapy, a 62% cure rate can be shown. In those patients with Stage IIb and III disease, a haemoglobin level during treatment of below 12 g% was associated with a significantly higher pelvic recurrence rate, and also lower cure rate, than for those with a haemoglobin level 12g% or more. A prospective study shows that the correction of anaemia is associated with a decreased pelvic recurrence rate and an increased cure rate consistent with tumour hypoxia being greater in anaemic patients than in those with a normal haemoglobin level. It is also consistent with the thesis that hypoxia controls the radiation local control rate in patients with advanced carcinoma of the cervix.

  15. Diamine curing agents for polyurethanes

    NASA Technical Reports Server (NTRS)

    Bell, V. L.; St. Clair, T. L.

    1975-01-01

    Three aromatic diamines have properties that make them promising candidates as curing agents for converting isocyanates to polyurethanes with higher adhesive strengths, higher softening temperatures, better toughness, and improved abrasion resistance.

  16. Correlation of cure monitoring techniques

    NASA Astrophysics Data System (ADS)

    Chang, S. S.; Mopsik, F. I.; Hunston, D. L.

    Six different composite matrix or neat resin cure-monitoring methods are presently used to follow the cure process in a model epoxy system, and the results obtained are compared. Differential scanning calorimetry, viscosity monitoring, the ultrasonic shear wave propagation technique, dielectric spectrometry, and two different fluorescence intensity techniques are compared with a view to common traits and differences. Dielectric fluorescence and ultrasonic measurement techniques are noted to be applicable to on-line process monitoring.

  17. Plasmid curing of Oenococcus oeni.

    PubMed

    Mesas, Juan M; Rodríguez, M Carmen; Alegre, M Teresa

    2004-01-01

    Two strains of Oenococcus oeni, RS1 (which carries the plasmid pRS1) and RS2 (which carries the plasmids pRS2 and pRS3), were grown in the presence of different curing agents and at different temperatures. Sublethal temperature together with acriflavine generated all possible types of cured strains, i.e., lacking pRS1 (from strain RS1), and lacking pRS2, pRS3, or both (from strain RS2). Sublethal temperature together with acridine orange only generated cured strains lacking pRS3. These results suggest that acriflavine is a better curing agent than acridine orange for O. oeni, and that pRS3 is the most sensitive to these curing agents. We also observed spontaneous loss of pRS2 or both pRS2 and pRS3 by electroporation. The ability to cure O. oeni strains of plasmids provides a critical new tool for the genetic analysis and engineering of this commercially important bacterium.

  18. Curing units' ability to cure restorative composites and dual-cured composite cements under composite overlay.

    PubMed

    Park, Sung-Ho; Kim, Su-Sun; Cho, Yong-Sik; Lee, Chang-Kyu; Noh, Byng-Duk

    2004-01-01

    This study compared the efficacy of using conventional low-power density QTH (LQTH) units, high-power density QTH (HQTH) units, argon (Ar) laser and Plasma arc curing (PAC) units for curing dual-cured resin cements and restorative resin composites under a pre-cured resin composite overlay. The microhardness of the two types of restorative resins (Z100 and Tetric Ceram) and a dual-cured resin cement (Variolink II) were measured after they were light cured for 60 seconds in a 2 mm Teflon mold. The recorded microhardness was determined to be the optimum microhard-ness (OM). Either one of the two types of restorative resins (Z100, Tetric Ceram) or the dual cured resin cement (Variolink II) were placed under a 1.5-mm thick and 8 mm diameter pre-cured Targis (Vivadent/Ivoclar AG, Schaan, Liechtenstein) overlay. The specimens that were prepared for each material were divided into four groups depending upon the curing units used (HQTH, PAC, Laser or LQTH) and were further subdi-vided into subgroups according to light curing time. The curing times used were 30, 60, 90 and 120 seconds for HQTH; 12, 24, 36 and 48 seconds for the PAC unit; 15, 30, 45 and 60 for the Laser and 60, 120 or 180 seconds for the LQTH unit. Fifteen specimens were assigned to each sub- group. The microhardness of the upper and and lower composite surfaces under the Targis overlay were measured using an Optidur Vickers hardness-measuring instrument (Göttfert Feinwerktechnik GmbH, Buchen, Germany). In each material, for each group, a three-way ANOVA with Tukey was used at the 0.05 level of significance to compare the microhardnesses of the upper and lower composite surfaces and the previously measured OM of the material. From the OM of each material, 80% OM was calculated and the time required for the microhardness of the upper and lower surface of the specimen to reach 100% and 80% of OM was determined. In Z100 and Tetric Ceram, when the composites were light cured for 120 seconds using the HQTH lamp

  19. Curing properties of furfuryl alcohol condensate with carbonaceous fine particles under ultrasonication.

    PubMed

    Hoshi, K; Akatsu, T; Tanabe, Y; Yasuda, E

    2001-04-01

    Ultrasonic treatment (sonication) was carried out through the curing process of furan resin by using an ultrasonic homogenizer at the frequency of 20 kHz and the various intensities (0-90 W). Various carbonaceous fine particles were added to furan resin to investigate the change of polymerization degree. The curing rate of furan resin was accelerated by sonication, which increased the polymerization degree with an increase in ultrasound intensity. The increase of curing rate was also observed by small additions of carbonaceous fine particles. In this case, the curing rate was increased with an increase in the specific surface area on additives.

  20. Cure rates for tuberculosis in the municipality of Rio de Janeiro, Brazil, in 2012 compared with coverage by, and time of establishment of, Family Health units, and socio-economic and demographic factors.

    PubMed

    Prado Junior, José Carlos; Virgilio, Thiago Costa; Medronho, Roberto de Andrade

    2016-05-01

    Tuberculosis (TB) has high prevalence and is considered a world emergency by the World Health Organization (WHO), being the greatest cause of death from infectious diseases in adults. It is directly associated with access to health services and socio-economic factors. A reform of Primary Care in the municipality of Rio de Janeiro began in 2010, with coverage increasing from 7% in that year to 48.2% in 2014. This article compares the proportion of cures of TB, coverage by the Family Health Strategy (FHS), how long it has been in place, and socio-economic and demographic factors in the municipality of Rio, based on new cases notified in the year 2012. An association was found between cure of TB and the variable gender, being 40% greater in females - odds ratio 1.4 (CI95% 1.21-1.62); and with residence in favelas - OR 0.86 (CI95% 0.73-1.02), but there was no association with coverage of the FHS (OR 1.06; CI95% 0.92-1.22), nor with the time for which the teams had been in place. FHS coverage in the municipality of Rio was put in place as priority in areas of greater vulnerability; at the time of this study, more than 91% of the teams had been in place for less than five years before the date of diagnosis. These factors probably contributed to it not being possible to detect better results in the cure of tuberculosis in areas covered by the FHS in the year 2012.

  1. Dynamically cured thermoplastic olefin polymers

    SciTech Connect

    Hazelton, D.R.; Puydak, R.C.; Booth, D.A.

    1986-08-19

    A thermoplastic composition is described comprising a polyolefin resin, a first rubber component selected from the group consisting of polyisobutylene, and ethylene propylene copolymer (EPM) and EPDM and a second rubber component selected from the group consisting of halogenated butyl rubber and polychoroprene, the second rubber component being cured utilizing a curative other than a peroxide, which is a vulcanizing agent for the second rubber but not for the first rubber, the second rubber being cured to a fully vulcanized state by dynamic vulcanization in the presence of the polyolefin resin and first rubber compound.

  2. Designing Cure Cycles for Matrix/Fiber Composite Parts

    NASA Technical Reports Server (NTRS)

    Hou, Tan-Hung

    2006-01-01

    A methodology has been devised for designing cure cycles to be used in the fabrication of matrix/fiber composite parts (including laminated parts). As used here, cure cycles signifies schedules of elevated temperature and pressure as functions of time, chosen to obtain desired rates of chemical conversion of initially chemically reactive matrix materials and to consolidate the matrix and fiber materials into dense solids. Heretofore, cure cycles have been designed following an empirical, trial-and-error approach, which cannot be relied upon to yield optimum results. In contrast, the present methodology makes it possible to design an optimum or nearly optimum cure cycle for a specific application. Proper design of a cure cycle is critical for achieving consolidation of a reactive matrix/fiber layup into a void-free laminate. A cure cycle for a composite containing a reactive resin matrix usually consists of a two-stage ramp-and-hold temperature profile. The temperature and the duration of the hold for each stage are unique for a given composite material. The first, lower-temperature ramp-and hold stage is called the B stage in composite- fabrication terminology. At this stage, pressure is not applied, and volatiles (solvents and reaction by-products) are free to escape. The second, higher-temperature stage is for final forced consolidation.

  3. Breather cloth for vacuum curing

    NASA Technical Reports Server (NTRS)

    Reed, M. W.

    1979-01-01

    Finely-woven nylon cloth that has been treated with Teflon improves vacuum adhesive bonding of coatings to substrates. Cloth is placed over coating; entire assembly, including substrate, coating, and cloth, is placed in plastic vacuum bag for curing. Cloth allows coating to "breathe" when bag is evacuated. Applications include bonding film coatings to solar concentrators and collectors.

  4. Cleaner Vacuum-Bag Curing

    NASA Technical Reports Server (NTRS)

    Clemons, J. M.; Penn, B. G.; Ledbetter, Frank E., III; Daniels, J. G.

    1987-01-01

    Improvement upon recommended procedures saves time and expense. Autoclave molding in vacuum bag cleaner if adhesive-backed covering placed around caul plate as well as on mold plate. Covering easy to remove after curing and leaves caul plate free of resin deposits.

  5. Cure shrinkage in casting resins

    SciTech Connect

    Spencer, J. Brock

    2015-02-01

    A method is described whereby the shrinkage of a casting resin can be determined. Values for the shrinkage of several resin systems in frequent use by Sandia have been measured. A discussion of possible methods for determining the stresses generated by cure shrinkage and thermal contraction is also included.

  6. Dielectric Analysis of Thermoset Cure.

    DTIC Science & Technology

    1985-10-07

    the polymerization of thermosetting polymers, 3. Polyst . Sci., 31, 30S (1959) 58. Warfield, R. V. * Petro*, M. C.: A study of the polymerization of...cure: isothemal curs kinetics, Ihermochimica Acta, 14. 41 (1976) 64. ludd. N. C. W.: Investigation of the polymerization of an unsaturated polyester

  7. Clinical effect of reducing curing times with high-intensity LED lights

    PubMed Central

    Ward, Justin D.; Wolf, Bethany J.; Leite, Luis P.; Zhou, Jing

    2016-01-01

    Objective To evaluate the clinical performance of brackets cured with a high-intensity, light-emitting diode (LED) with a shorter curing time. Materials and Methods Thirty-four patients and a total of 680 brackets were examined using a randomized split-mouth design. The maxillary right and mandibular left quadrants were cured for 6 seconds with a high-intensity LED light (3200 mW/cm2) and the maxillary left and mandibular right quadrants were cured for 20 seconds with a standard-intensity LED light (1200 mW/cm2). Alternating patients had the quadrants inverted for the curing protocol. The number and date of each first-time bracket failure was recorded from 199 to 585 days posttreatment. Results The bracket failure rate was 1.18% for both curing methods. The proportion of bracket failure was not significantly different between curing methods (P = 1.000), genders (P = 1.000), jaws (P = .725), sides (P = .725), or quadrants (P = .547). Posterior teeth exhibited a greater proportion of failures (2.21%) relative to anterior teeth (0.49%), although the difference was not statistically significant (P = .065). Conclusions No difference was found in bond failure rates between the two curing methods. Both methods showed bond failure rates low enough to be considered clinically sufficient. The high-intensity LED light used with a shorter curing time may be considered an advantage due to the reduced chair time. PMID:25760887

  8. Accelerated Cure Project for Multiple Sclerosis

    MedlinePlus

    ... main content Accelerating research toward a cure for multiple sclerosis Home Contact Us Search form Search Connect Volunteer ... is to accelerate efforts toward a cure for multiple sclerosis by rapidly advancing research that determines its causes ...

  9. FDA Warns Against Bogus Autism 'Cures'

    MedlinePlus

    ... news/fullstory_164602.html FDA Warns Against Bogus Autism 'Cures' Unproven therapies won't help and could ... Don't fall for products claiming to cure autism, the U.S. Food and Drug Administration warns. There's ...

  10. Monitoring Polymer Curing Via Electromagnetic Impedance

    NASA Technical Reports Server (NTRS)

    Freeman, William T.; Covington, John C.; Kranbuehl, David E.; Hoff, Melanie; Delos, Susan

    1992-01-01

    New nondestructive in-situ electromagnetic-impedance measurement technique senses cure-processing properties of high-temperature, high-performance thermostat and thermoplastic resins. Continuous frequency-dependent measurement and analysis performed during curing cycle. Monitors and measures molecular properties of polymeric resin in liquid and solid states. Applications include nondestructive means for evaluation of materials, determination of "window" boundaries of curing cycles of thermoplastics and thermoset resins, and for online, closed-loop control of curing cycles.

  11. Cure of cancer for seven cancer sites in the Flemish Region.

    PubMed

    Silversmit, Geert; Jegou, David; Vaes, Evelien; Van Hoof, Elke; Goetghebeur, Els; Van Eycken, Liesbet

    2017-03-01

    Cumulative relative survival curves for many cancers reach a plateau several years after diagnosis, indicating that the cancer survivor group has reached "statistical" cure. Parametric mixture cure model analysis on grouped relative survival curves provide an interesting way to determine the proportion of statistically cured cases and the mean survival time of the fatal cases in particular for population-based cancer registries. Based on the relative survival data from the Belgian Cancer Registry, parametric cure models were applied to seven cancer sites (cervix, colon, corpus uteri, skin melanoma, pancreas, stomach and oesophagus), at the Flemish Regional level for the incidence period 1999-2011. Statistical cure was observed for the examined cancer sites except for oesophageal cancer. The estimated cured proportion ranged from 5.9% [5.7, 6.1] for pancreatic cancer to 80.8% [80.5, 81.2] for skin melanoma. Cure results were further stratified by gender or age group. Stratified cured proportions were higher for females compared to males in colon cancer, stomach cancer, pancreas cancer and skin melanoma, which can mainly be attributed to differences in stage and age distribution between both sexes. This study demonstrates the applicability of cure rate models for the selected cancer sites after 14 years of follow-up and presents the first population-based results on the cure of cancer in Belgium.

  12. 7 CFR 51.1412 - Well cured.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false Well cured. 51.1412 Section 51.1412 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Well cured. Well cured means that the kernel separates freely from the shell, breaks cleanly when...

  13. 7 CFR 51.1412 - Well cured.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false Well cured. 51.1412 Section 51.1412 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Standards for Grades of Pecans in the Shell 1 Definitions § 51.1412 Well cured. Well cured means that...

  14. 7 CFR 51.1412 - Well cured.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false Well cured. 51.1412 Section 51.1412 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Well cured. Well cured means that the kernel separates freely from the shell, breaks cleanly when...

  15. 7 CFR 51.1412 - Well cured.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Well cured. 51.1412 Section 51.1412 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Standards for Grades of Pecans in the Shell 1 Definitions § 51.1412 Well cured. Well cured means that...

  16. Composite Curing Process Nondestructive Evaluation

    DTIC Science & Technology

    1988-06-01

    selected cure cycles, and conservative methods have been adopted to offset potentially degrading conditions. This approach invariably increases...fluoresce in ordinary solvents will, however, fluoresce strongly in viscous media such as glycerol at low temperatures. A number of studies on the...viscosity solvents is due to fasL nonradiative deactivation (relaxation) of the excited state by intramolecular torsional motions. When such torsional

  17. Hybrid Helmet Cure Cycle Optimization

    DTIC Science & Technology

    2008-02-01

    Distribution List 11 iv List of Figures Figure 1. DSC scans of cured and uncured carbon fiber-epoxy prepreg ...thermoplastic fabrics, molded with thermoset prepregs was designed at ARL. Proposed manufacturing of the helmet involved pressure molding a number...of plies of aramid fabric with a thermoplastic film, and two plies of carbon fiber-epoxy prepreg , BT250-E (Bryte Technologies, Inc.) that would add

  18. High Flow Addition Curing Polyimides

    NASA Technical Reports Server (NTRS)

    Chuang, Kathy C.; Vannucci, Raymond D.; Ansari, Irfan; Cerny, Lawrence L.; Scheiman, Daniel A.

    1994-01-01

    A new series of high flow PMR-type addition curing polyimides was developed, which employed the substitution of 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (BTDB) for p-phenylenediamine (p -PDA) in a PMR-IL formulation. These thermoset polyimides, designated as 12F resins, were prepared from BTDB and the dimethyl ester of 4,4'- (hexafluo- roisopropylidene) -diphthalic acid (HFDE) with either nadic ester (NE) or p-aminostyrene (PAS) as the endcaps for addition curing. The 12F prepolymers displayed lower melting temperatures in DSC analysis, and higher melt flow in rheological studies than the cor- responding PMR-11 polyimides. Long-term isothermal aging studies showed that BTDB- based 12F resins exhibited comparable thermo-oxidative stability to P-PDA based PMR-11 polyimides. The noncoplanar 2- and 2'-disubstituted biphenyldiamine (BTDB) not only lowered the melt viscosities of 12F prepolymers, but also retained reasonable thermal sta- bility of the cured resins. The 12F polyimide resin with p-aminostyrene endcaps showed the best promise for long-term, high-temperature application at 343 C (650 F).

  19. Cure shrinkage of thermoset composites

    SciTech Connect

    Russell, J.D. )

    1993-01-01

    The shrinkage of thermoset composites during cure was studied using a volumetric dilatometer. The material systems studied were AS4 carbon fiber/Hercules' 3501-6 epoxy, IM7 carbon fiber/Hercules 8551-7A toughened epoxy and IM7 carbon fiber/BASF's 5250-4 bismaleimide. Shrinkage of the samples due to both polymerization and thermal expansion effects was seen. The volume changes of the materials during cure were then compared to results from dynamic mechanical analysis (DMA) and dielectric cure monitoring. Maximums in volume corresponded to minimums in storage and loss modulus from DMA and maximums in the dielectric loss factor. Resin shrinkage during the 177 deg C (350 F) hold corresponded to the onset of polymerization seen by the rapid increase in the storage modulus and the decrease in the dielectric loss factor response due to reduced ion mobility. These results show that volumetric dilatometry can be an effective tool in the development of materials processing strategies and can be useful in studying residual stresses in composites. 9 refs.

  20. Freud's psychoanalysis: a moral cure.

    PubMed

    Eriksson, Johan

    2014-08-01

    That psychoanalytical treatment in its classical Freudian sense is primarily a moral or ethical cure is not a very controversial claim. However, it is far from obvious how we are to understand precisely the moral character of psychoanalysis. It has frequently been proposed that this designation is valid because psychoanalysis strives neither to cure psychological symptoms pharmaceutically, nor to superficially modify the behaviour of the analysand, but to lead the analysand through an interpretive process during which he gradually gains knowledge of the unconscious motives that determine his behaviour, a process that might ideally liberate him to obtain, in relation to his inner desires, the status of a moral agent. There resides something appealing in these claims. But it is the author's belief that there is an even deeper moral dimension applying to psychoanalytical theory and praxis. Freudian psychoanalysis is a moral cure due to its way of thematizing psychological suffering as moral suffering. And this means that the moral subject - the being that can experience moral suffering - is not primarily something that the psychoanalytical treatment strives to realize, but rather the presupposition for the way in which psychoanalysis theorizes psychological problems as such.

  1. From HCV To HBV Cure.

    PubMed

    Schinazi, Raymond F; Asselah, Tarik

    2017-01-01

    Approximately 170 million people are chronically infected with HCV and 350 million are chronically infected with HBV worldwide. It is estimated that more than one million patients die from complications related to chronic viral hepatitis, mainly HCC which is one of the most frequent cancers in many countries, especially Africa, the Middle East and Asia. HCV drug development has been impressive, and this revolution led to several direct-acting antiviral agents achieving an HCV cure after only 6-12 weeks. This progress could theorically lead to HCV global elimination making HCV and its consequences a rarity. HBV research and development programs can learn from the HCV experience, to achieve an HBV functional or sterilizing cure. This review will summarize key steps which have been realized for an HCV cure, and discuss the next steps to achieve for an HCV elimination. And also, how this HCV revolution has inspired scientists and clinicians to achieve the same for HBV.

  2. Photo-Curing: UV Radiation curing of polymers

    NASA Technical Reports Server (NTRS)

    Inman, Christina A.

    2004-01-01

    The Polymers Branch of the Materials Division is dedicated to the development of high-performance for a variety of applications. Areas of significant interest include high- temperature polymers, low density, and high strength insulating materials, conductive polymers, and high density polymer electrolytes. This summer our group is working diligently on a photo-curing project. There is interest in the medical community feel the need for a new and improved balloon that will be used for angioplasty (a form of heart surgery). This product should maintain flexibility but add many other properties. Like possibly further processability and resistance to infection. Our group intends on coming up with this product by using photo-enolization (or simply, photo-curing) by Diels-Alder trapping. The main objective was to synthesize a series of new polymers by Diels-Alder cycloaddition of photoenols with more elastomeric properties. Our group was responsible for performing the proper photo-curing techniques of the polymers with diacrylates and bismaleimides, synthesizing novel monomers, and evaluating experimental results. We attempted to use a diacrylate to synthesize the polymer because of previous research done within the Polymers Branch here at NASA. Most acrylates are commercially available, have more elastometric properties than a typical rigid aromatic structure has and they contain ethylene oxides in the middle of their structure that create extensive flexibility. The problem we encountered with the acrylates is that they photo chemically and thermally self polymerize and create diradicals at low temperatures; these constraints caused a lot of unnecessary side reactions. We want to promote solely, diketone polymerization because this type of polymerization has the ability to cause very elastic polymers. We chose to direct our attention towards the usage of maleimides because they are known for eliminating these unnecessary side reactions.

  3. Is Curing Behavior Dependent on Morphology in Reactive Polyurethanes

    NASA Astrophysics Data System (ADS)

    Jeong, Young Gyu; Hashida, Tomoko; Krishnamoothy, Jayaraman; Hsu, Shaw Ling

    2004-03-01

    Reactive polyurethanes usually are formulated as ternary polymer blends whose components are often crystalline polyester, amorphous polyether, and acrylate with high glass transition temperature. Therefore, the morphology developed is highly dependent on the composition and thermal history. Ambient water vapor reacts with the isocyanate-terminated prepolymers, which leads to increase in molecular weight and mechanical properties achievable. Previously, there have been limited studies describing this reaction process. We have investigated the morphological and compositional effects on curing kinetics and chemical reactions induced by water vapor diffusion into prepolymer using time-resolved reflection-absorption infrared spectroscopy, optical microscopy, and atomic force microscopy. It was found that the curing kinetics is strongly related to the prepolymer composition, which affects the molecular mobility, hydrophilicity, phase separation, and crystallization. In addition, we found that the curing rate decreased significantly with the development of liquid/liquid phase separation.

  4. Curing depth of composite resin light cured by LED and halogen light-curing units

    NASA Astrophysics Data System (ADS)

    Calixto, L. R.; Lima, D. M.; Queiroz, R. S.; Rastelli, A. N. S.; Bagnato, V. S.; Andrade, M. F.

    2008-11-01

    The purpose of this study was to evaluate the polymerization effectiveness of a composite resin (Z-250) utilizing microhardness testing. In total, 80 samples with thicknesses of 2 and 4 mm were made, which were photoactivated by a conventional halogen light-curing unit, and light-curing units based on LED. The samples were stored in water distilled for 24 h at 37°C. The Vickers microhardness was performed by the MMT-3 microhardness tester. The microhardness means obtained were as follows: G1, 72.88; G2, 69.35; G3, 67.66; G4, 69.71; G5, 70.95; G6, 75.19; G7, 72.96; and G8, 71.62. The data were submitted to an analysis of variance (ANOVA’s test), adopting a significance level of 5%. The results showed that, in general, there were no statistical differences between the halogen and LED light-curing units used with the same parameters.

  5. Plasma arc versus halogen light curing of orthodontic brackets: a 12-month clinical study of bond failures.

    PubMed

    Sfondrini, Maria Francesca; Cacciafesta, Vittorio; Scribante, Andrea; Klersy, Catherine

    2004-03-01

    The purpose of this randomized clinical trial was to evaluate the clinical performance of brackets cured with 2 different light-curing units (conventional halogen light and plasma arc light); 83 patients treated with fixed appliances were included in the study. With the "split-mouth" design, each patient's mouth was divided into 4 quadrants. In 42 randomly selected patients, the maxillary left and mandibular right quadrants were cured with the halogen light, and the remaining quadrants were cured with the plasma arc light. In the other 41 patients, the quadrants were inverted. A total of 1434 stainless steel brackets were examined: 717 were cured with a conventional halogen light for 20 seconds; the remaining 717 were cured with the plasma arc light for 5 seconds. The number, cause, and date of bracket failures were recorded for each light-curing unit over 12 months. Statistical analysis was performed with the Fisher exact test, the Kaplan-Meier survival estimates, and the log-rank test. No statistically significant differences were found between the total bond failure rates of the brackets cured with the halogen light and those cured with the plasma arc light. Neither were significant differences found when the clinical performances of the maxillary versus mandibular arches or the anterior versus posterior segments were compared. These findings demonstrate that plasma arc lights are an advantageous alternative to conventional light curing, because they significantly reduce the curing time of orthodontic brackets without affecting the bond failure rate.

  6. Ambient Cured Alkali Activated Flyash Masonry Units

    NASA Astrophysics Data System (ADS)

    Venugopal, K.; Radhakrishna; Sasalatti, Vinod M.

    2016-09-01

    Geopolymers belong to a category of non-conventional and non-Portland cement based cementitious binders which are produced using industrial by products like fly ash and ground granulated blast furnace slag (GGBFS). This paper reports on the development of geopolymer mortars for production of masonry units. The geopolymer mortars were prepared by mixing various by products with manufactured sand and a liquid mixture of sodium silicate and sodium hydroxide solutions. After curing at ambient conditions, the masonry units were tested for strength properties such as water absorption, initial rate of absorption, compression, shear- bond, and stress-strain behaviour etc. It was observed that the flexural strength of the blocks is more than 2 MPa and shear bond strength is more than 0.4MPa. It was found that the properties of geopolymer blocks were superior to the traditional masonry units. Hence they can be recommended for structural masonry.

  7. Microelectrode fabrication by laser direct curing of tiny nanoparticle self-generated from organometallic ink.

    PubMed

    Kang, Bongchul; Ko, Seunghwan; Kim, Jongsu; Yang, Minyang

    2011-01-31

    In this paper, we present a new laser direct patterning method that selectively cures nanoparticles self-generated from organometallic ink by proper thermal decomposition. This approach has several advantages in the curing rate, resolution and pattern quality compared with the conventional nanoparticle ink based direct laser curing method. It was found that a laser wavelength which is more weakly absorbed by the nanoparticles could produce a more stable and homogeneous curing condition. Finally, arbitrary shaped silver electrodes with narrow width and uniform profile could be achieved on a polymer substrate at a high curing rate of 25 mm/s. This process can be applied for flexible electronics fabrications on heat sensitive polymer substrates.

  8. Chromothriptic Cure of WHIM Syndrome

    PubMed Central

    McDermott, David H.; Gao, Ji-Liang; Liu, Qian; Siwicki, Marie; Martens, Craig; Jacobs, Paejonette; Velez, Daniel; Yim, Erin; Bryke, Christine R.; Hsu, Nancy; Dai, Zunyan; Marquesen, Martha M.; Stregevsky, Elina; Kwatemaa, Nana; Theobald, Narda; Long Priel, Debra A.; Pittaluga, Stefania; Raffeld, Mark A.; Calvo, Katherine R.; Maric, Irina; Desmond, Ronan; Holmes, Kevin L.; Kuhns, Douglas B.; Balabanian, Karl; Bachelerie, Françoise; Porcella, Stephen F.; Malech, Harry L.; Murphy, Philip M.

    2015-01-01

    Summary Chromothripsis is a catastrophic cellular event recently described in cancer in which chromosomes undergo massive deletion and rearrangement. Here we report a case in which chromothripsis spontaneously cured a patient with WHIM syndrome, an autosomal dominant combined immunodeficiency disease caused by gain-of-function mutation of the chemokine receptor CXCR4. In this patient, deletion of the disease allele, CXCR4R334X, as well as 163 other genes from one copy of chromosome 2 occurred in a hematopoietic stem cell (HSC) that repopulated the myeloid but not the lymphoid lineage. In competitive mouse bone marrow (BM) transplantation experiments, Cxcr4 haploinsufficiency was sufficient to confer a strong long-term engraftment advantage of donor BM over BM from either wild-type or WHIM syndrome model mice, suggesting a potential mechanism for the patient’s cure. Our findings suggest that partial inactivation of CXCR4 may have general utility as a strategy to promote HSC engraftment in transplantation. PMID:25662009

  9. ASRM test report: Autoclave cure process development

    NASA Technical Reports Server (NTRS)

    Nachbar, D. L.; Mitchell, Suzanne

    1992-01-01

    ASRM insulated segments will be autoclave cured following insulation pre-form installation and strip wind operations. Following competitive bidding, Aerojet ASRM Division (AAD) Purchase Order 100142 was awarded to American Fuel Cell and Coated Fabrics Company, Inc. (Amfuel), Magnolia, AR, for subcontracted insulation autoclave cure process development. Autoclave cure process development test requirements were included in Task 3 of TM05514, Manufacturing Process Development Specification for Integrated Insulation Characterization and Stripwind Process Development. The test objective was to establish autoclave cure process parameters for ASRM insulated segments. Six tasks were completed to: (1) evaluate cure parameters that control acceptable vulcanization of ASRM Kevlar-filled EPDM insulation material; (2) identify first and second order impact parameters on the autoclave cure process; and (3) evaluate insulation material flow-out characteristics to support pre-form configuration design.

  10. ASRM test report: Autoclave cure process development

    NASA Astrophysics Data System (ADS)

    Nachbar, D. L.; Mitchell, Suzanne

    1992-05-01

    ASRM insulated segments will be autoclave cured following insulation pre-form installation and strip wind operations. Following competitive bidding, Aerojet ASRM Division (AAD) Purchase Order 100142 was awarded to American Fuel Cell and Coated Fabrics Company, Inc. (Amfuel), Magnolia, AR, for subcontracted insulation autoclave cure process development. Autoclave cure process development test requirements were included in Task 3 of TM05514, Manufacturing Process Development Specification for Integrated Insulation Characterization and Stripwind Process Development. The test objective was to establish autoclave cure process parameters for ASRM insulated segments. Six tasks were completed to: (1) evaluate cure parameters that control acceptable vulcanization of ASRM Kevlar-filled EPDM insulation material; (2) identify first and second order impact parameters on the autoclave cure process; and (3) evaluate insulation material flow-out characteristics to support pre-form configuration design.

  11. Interfacial Properties of Electron Beam Cured Composites

    SciTech Connect

    Eberle, C.C.

    1999-12-30

    The objectives of the CRADA are to: Confirm that fiber-resin adhesion is responsible for the observed poor shear properties; Determine the mechanism(s) responsible for poor adhesion between carbon fibers and epoxy resins after e-beam curing; Develop and evaluate resin systems and fiber treatments to improve the properties of e-beam cured, carbon-fiber-reinforced composites; and Develop refined methods for processing e-beam cured, carbon-fiber-reinforced composites.

  12. New "cures" for ailing communications.

    PubMed

    Johnston, B

    1988-07-01

    The benefits of voice processing technologies applied "one piece at a time" in the proper fashion can provide four "cures" to communications problems: The image of the healthcare facility in the eyes of the public will improve because calls are handled more quickly, efficiently, and professionally than before. Providing faster patient care information and eliminating delays in medical staff and personnel communications creates the opportunity to give better patient care and customer service. Elimination of time wasting "telephone tag" and "memo blizzards" will result in an increase in employee productivity. Personnel can be reassigned to more productive tasks. The net effect of voice processing on the healthcare industry is a continued merging of computers and telephones, resulting in a voice capability system which includes the telephone system, the call processing system, the voice messaging system, the voice response system, and the host computer system, all being accessed by the same terminal. Just the basic plain-vanilla touchtone telephone will handle it all.

  13. Changes on degree of conversion of dual-cure luting light-cured with blue LED

    NASA Astrophysics Data System (ADS)

    Bandéca, M. C.; El-Mowafy, O.; Saade, E. G.; Rastelli, A. N. S.; Bagnato, V. S.; Porto-Neto, S. T.

    2009-05-01

    The indirect adhesive procedures constitute recently a substantial portion of contemporary esthetic restorative treatments. The resin cements have been used to bond tooth substrate and restorative materials. Due to recently introduction of the self-bonding resin luting cement based on a new monomer, filler and initiation technology has become important to study the degree of conversion of these new materials. In the present work the polymerization reaction and the filler content of dual-cured dental resin cements were studied by means of infra-red spectroscopy (FT-IR) and thermogravimetry (TG). Twenty specimens were made in a metallic mold (8 mm diameter × 1 mm thick) from each of 2 cements, Panavia® F2.0 (Kuraray) and RelyX™ Unicem Applicap (3M/ESPE). Each specimen was cured with blue LED with power density of 500 mW/cm2 for 30 s. Immediately after curing, 24 and 48 h, and 7 days DC was determined. For each time interval 5 specimens were pulverized, pressed with KBr and analyzed with FT-IR. The TG measurements were performed in Netzsch TG 209 under oxygen atmosphere and heating rate of 10°C/min from 25 to 700°C. A two-way ANOVA showed DC (%) mean values statistically significance differences between two cements ( p < 0.05). The Tukey’s test showed no significant difference only for the 24 and 48 h after light irradiation for both resin cements ( p > 0.05). The Relx-Y™ Unicem mean values were significantly higher than Panavia® F 2.0. The degree of conversion means values increasing with the storage time and the filler content showed similar for both resin cements.

  14. Ohmic Curing of Printed Silver Conductive Traces

    NASA Astrophysics Data System (ADS)

    Roberson, D. A.; Wicker, R. B.; MacDonald, E.

    2012-09-01

    Ohmic heating was demonstrated as a novel curing method (or curing enhancement) useful in decreasing the resistivity of conductive traces printed with both micro- and nanoparticle-loaded inks while (1) only locally heating the substrate and (2) curing in a matter of seconds compared with the range of 30 min to 1 h required by traditional oven-curing. In one experiment using traces composed of microparticle ink, which required initial air-drying as a preprocess step, application of an ohmic curing cycle resulted in resistivity of 80 nΩ m, roughly six times that of bulk silver. In a second experiment employing nanoparticle inks, which required an initial thermal cure as a preprocess, a resistivity of 43 nΩ m, roughly three times that of bulk silver, was attained after the application of an ohmic curing cycle. Electrical characterization of the ohmic curing process was performed in real time to understand the impact of cycling and duration on the resulting conductivity. Finally, the effect of printed trace length on the ohmic curing process was explored and found to have a near-linear relationship with the reduction in resistance when the applied electrical current was normalized to measured resistance. The microstructural changes which occurred as a result of ohmic curing such as particle sintering and grain growth were characterized by scanning electron microscopy. The results presented in this work demonstrate the use of ohmic heating to overcome temperature limitations imposed on a thermal curing process by substrate material properties or other sources.

  15. LED Curing Lights and Temperature Changes in Different Tooth Sites

    PubMed Central

    Armellin, E.; Bovesecchi, G.; Coppa, P.; Pasquantonio, G.; Cerroni, L.

    2016-01-01

    Objectives. The aim of this in vitro study was to assess thermal changes on tooth tissues during light exposure using two different LED curing units. The hypothesis was that no temperature increase could be detected within the dental pulp during polymerization irrespective of the use of a composite resin or a light-curing unit. Methods. Caries-free human first molars were selected, pulp residues were removed after root resection, and four calibrated type-J thermocouples were positioned. Two LED lamps were tested; temperature measurements were made on intact teeth and on the same tooth during curing of composite restorations. The data was analyzed by one-way analysis of variance (ANOVA), Wilcoxon test, Kruskal-Wallis test, and Pearson's χ2. After ANOVA, the Bonferroni multiple comparison test was performed. Results. Polymerization data analysis showed that in the pulp chamber temperature increase was higher than that without resin. Starlight PRO, in the same condition of Valo lamp, showed a lower temperature increase in pre- and intrapolymerization. A control group (without composite resin) was evaluated. Significance. Temperature increase during resin curing is a function of the rate of polymerization, due to the exothermic polymerization reaction, the energy from the light unit, and time of exposure. PMID:27195282

  16. Ultrasonic mixing of epoxy curing agents

    NASA Technical Reports Server (NTRS)

    Hodges, W. T.; St.clair, T. L.

    1983-01-01

    A new technique for mixing solid curing agents into liquid epoxy resins using ultrasonic energy was developed. This procedure allows standard curing agents such as 4,4 prime-diaminodiphenyl sulfone (4,4 prime-DDS) and its 3,3 prime-isomer, (3,3 prime-DDS) to be mixed without prior melting of the curing agent. It also allows curing agents such as 4,4 prime-diaminodiphenyl sulfone (4,4 prime-DDS) and its 3,3 prime-isomer, (3,3 prime-DDS) to be mixed without prior melting of the curing agent. It also allows curing agents with very high melt temperatures such as 4,4 prime-diaminobenzophenone (4,4 prime-DABP) (242 C) to be mixed without premature curing. Four aromatic diamines were ultrasonically blended into MY-720 epoxy resin. These were 4,4 prime-DDS; 3,3 prime-DDA; 4,4 prime-DABP and 3,3 prime-DABP. Unfilled moldings were cast and cured for each system and their physical and mechanical properties compared.

  17. 7 CFR 29.6010 - Cured.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Cured. 29.6010 Section 29.6010 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... INSPECTION Standards Definitions § 29.6010 Cured. Tobacco dried of its sap by either natural or...

  18. Evaluation of Degreasers as Brine Curing Additives

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The length of time needed for brine curing of raw hides and skins, a minimum of 18 h, is a time-consuming and expensive process. In this paper we initially report the results of an investigation of the stratigraphic distribution of sodium chloride and water in fleshed hides cured for varying interv...

  19. Curing of Graphite/Epoxy Composites.

    DTIC Science & Technology

    1983-03-01

    365-371 (1973). 21. Pappalardo , L. T., "DSC Evaluation of B-Stage Epoxy-Glass Prepregs For Multilayer Boards," SPE Technical Papers, 20, 13-16 (1974...Kamal, M. R., "Differential Scanning Calorimetry of Epoxy Cure: Isothermal Cure Kinetics," Thermochimica Acta, 14, 41-59 (1976). 24. Pappalardo , L. T

  20. Cure Chemistry of Phenylethynyl Terminated Oligomers

    NASA Technical Reports Server (NTRS)

    Wood, Karen H.; Orwoll, Robert A.; Young, Philip R.; Jensen, Brian J.; McNair, Harold M.

    1997-01-01

    The ability to process high performance polymers into quality, void-free composites has been significantly advanced using oligomers terminated with reactive groups which cure or crosslink at elevated temperature without the evolution of volatile byproducts. Several matrix resin systems of considerable interest to the aerospace community utilize phenylethynyl-terminated imide (PETI) technology to achieve this advantage. The present paper addresses the cure chemistry of PETI oligomers. The thermal cure of a low molecular weight model compound was studied using a variety of analytical techniques including differential scanning calorimetry, Fourier transform infrared spectroscopy, and liquid chromatography-mass spectroscopy. The studies indicate an extremely complex cure process. Many stable products were isolated and this paper reports current work on identification of those products. The intent of this research is to provide fundamental insight into the molecular structure of the cured PETI engineering materials so that performance and durability can be more fully assessed.

  1. 7 CFR 29.2519 - Fire-cured.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Fire-cured. 29.2519 Section 29.2519 Agriculture... INSPECTION Standards Official Standard Grades for Kentucky and Tennessee Fire-Cured and Foreign-Grown Fire-Cured Tobacco (u.s. Types 22, 23, and Foreign Type 96) § 29.2519 Fire-cured. Tobacco cured...

  2. 7 CFR 29.2519 - Fire-cured.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false Fire-cured. 29.2519 Section 29.2519 Agriculture... INSPECTION Standards Official Standard Grades for Kentucky and Tennessee Fire-Cured and Foreign-Grown Fire-Cured Tobacco (u.s. Types 22, 23, and Foreign Type 96) § 29.2519 Fire-cured. Tobacco cured...

  3. 7 CFR 29.2519 - Fire-cured.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Fire-cured. 29.2519 Section 29.2519 Agriculture... INSPECTION Standards Official Standard Grades for Kentucky and Tennessee Fire-Cured and Foreign-Grown Fire-Cured Tobacco (u.s. Types 22, 23, and Foreign Type 96) § 29.2519 Fire-cured. Tobacco cured...

  4. 7 CFR 29.2519 - Fire-cured.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false Fire-cured. 29.2519 Section 29.2519 Agriculture... INSPECTION Standards Official Standard Grades for Kentucky and Tennessee Fire-Cured and Foreign-Grown Fire-Cured Tobacco (u.s. Types 22, 23, and Foreign Type 96) § 29.2519 Fire-cured. Tobacco cured...

  5. 7 CFR 29.2519 - Fire-cured.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false Fire-cured. 29.2519 Section 29.2519 Agriculture... INSPECTION Standards Official Standard Grades for Kentucky and Tennessee Fire-Cured and Foreign-Grown Fire-Cured Tobacco (u.s. Types 22, 23, and Foreign Type 96) § 29.2519 Fire-cured. Tobacco cured...

  6. 9 CFR 319.103 - Cured beef tongue.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Cured beef tongue. 319.103 Section 319... Cured beef tongue. In preparing “Cured Beef Tongue,” the application of curing solution to the fresh beef tongue shall not result in an increase in the weight of the cured beef tongue of more than...

  7. Curing agent for polyepoxides and epoxy resins and composites cured therewith. [preventing carbon fiber release

    NASA Technical Reports Server (NTRS)

    Serafini, T. T.; Delvigs, P.; Vannucci, R. D. (Inventor)

    1981-01-01

    A curing for a polyepoxide is described which contains a divalent aryl radical such as phenylene a tetravalent aryl radical such as a tetravalent benzene radical. An epoxide is cured by admixture with the curing agent. The cured epoxy product retains the usual properties of cured epoxides and, in addition, has a higher char residue after burning, on the order of 45% by weight. The higher char residue is of value in preventing release to the atmosphere of carbon fibers from carbon fiber-epoxy resin composites in the event of burning of the composite.

  8. Curing efficiency of modern LED units.

    PubMed

    Rencz, Adam; Hickel, Reinhard; Ilie, Nicoleta

    2012-02-01

    Recent reports claim that modern light-emitting diode (LED) curing units improve curing efficiency by increasing the units' irradiance. In this context also, short polymerisation times up to 5 s are proposed. The aim of this study was to examine whether there are differences in the curing efficiency of modern LED curing units by assessing their effect on two different composite materials and by varying the irradiation time. A nano- and a micro-hybrid resin-based composite (RBC) were polymerised for 5, 10 and 20 s with three commercial and a Prototype LED unit (Elipar™ S10). Cylindrical specimens (6 mm in depth, 4 mm in diameter) were prepared in three increments, each 2-mm thick, and were consecutively cured. Degree of cure was measured for 20 min in real time at the bottom of the samples, starting with the photoinitiation. The micro-mechanical properties (modulus of elasticity, E and Vickers hardness, HV) were measured as a function of depth, in 100-μm steps, on the above described samples stored in distilled water for 24 h at 37°C. Data were analysed with multivariate ANOVA followed by Tukey's test, t test and partial eta-squared statistics. In descending order of the strength of their effect, the type of RBC, depth, polymerisation time and curing unit were significant factors affecting the micro-mechanical parameters (p < 0.05). The degree of cure at 6-mm depth was less but significantly influenced by the curing unit and curing time and was independent from the type of RBC. A 5-s irradiation time is not recommended for these units. Whereas a 5-s irradiation is acceptable at the sample's surface, a minimum of 20 s of irradiation is necessary for an adequate polymerisation 2 mm beyond the surface.

  9. Measurement techniques for evaluating encapsulant thermophysical properties during cure

    SciTech Connect

    Adolf, D.

    1996-06-01

    Sandia now has the capability to evaluate stresses during cure of epoxies with finite element codes. Numerous material parameters are needed as input to these codes. I present a relatively quick set of tests which enable evaluation of the required thermophysical properties. Ease and accuracy of the tests improve as the reaction rate of the thermoset slows. Material parameters for common encapsulants at Sandia are presented in tables.

  10. Effectiveness of light emitting diode and halogen light curing units for curing microhybrid and nanocomposites

    PubMed Central

    Choudhary, Shwetha; Suprabha, BS

    2013-01-01

    Aim: To compare the polymerization efficacy of micro-hybrid and nanocomposites cured with Quartz-tungsten halogen (QTH) and light emitting diode (LED) light curing units (LCUs). The effectiveness of pulse cure mode in LED LCU was also investigated. Materials and Methods: Both micro-hybrid and nanocomposite specimens were cured using four different curing protocols giving a total of eight experimental groups. Ten cylindrical specimens were prepared for each group, and light cured for 40 s on the top surface, thus giving a total of eighty specimens. Vicker hardness measurements were carried out on the top and bottom surfaces after 24 h and hardness ratio was calculated. Results: For both micro-hybrid and nanocomposites, highest mean VHN was observed for the group cured with QTH LCU, and the lowest was observed for the group cured with second LED LCU in standard mode but the difference was significant only in case of nanocomposite. Conclusion: Curing nanocomposites with QTH LCU results in better micro hardness. Pulse cure mode does not effectively increase polymerization efficacy than the standard mode of curing. PMID:23833457

  11. Extension of a Cox proportional hazards cure model when cure information is partially known

    PubMed Central

    Wu, Yu; Lin, Yong; Lu, Shou-En; Li, Chin-Shang; Shih, Weichung Joe

    2014-01-01

    When there is evidence of long-term survivors, cure models are often used to model the survival curve. A cure model is a mixture model consisting of a cured fraction and an uncured fraction. Traditional cure models assume that the cured or uncured status in the censored set cannot be distinguished. But in many practices, some diagnostic procedures may provide partial information about the cured or uncured status relative to certain sensitivity and specificity. The traditional cure model does not take advantage of this additional information. Motivated by a clinical study on bone injury in pediatric patients, we propose a novel extension of a traditional Cox proportional hazards (PH) cure model that incorporates the additional information about the cured status. This extension can be applied when the latency part of the cure model is modeled by the Cox PH model. Extensive simulations demonstrated that the proposed extension provides more efficient and less biased estimations, and the higher efficiency and smaller bias is associated with higher sensitivity and specificity of diagnostic procedures. When the proposed extended Cox PH cure model was applied to the motivating example, there was a substantial improvement in the estimation. PMID:24511081

  12. Help us find the cures.

    PubMed

    Morgan, Delyth

    2013-01-01

    Despite significant advances in research, breast cancer is still the most common form of cancer, with 50,000 cases diagnosed and 12,000 dying of the disease each year in the UK. In October 2013, Breast Cancer Campaign published a Gap Analysis of breast cancer research that provides us with what we need to know about and what we now need to do to overcome - prevent, cure and outlive - breast cancer. In addition to highlighting the gaps in our understanding of breast cancer, the paper identifies five strategic solutions, which require a collaborative approach amongst researchers in academia and industry, funders, donors, policy-makers and parliamentarians, healthcare professionals and patients to achieve significant progress. Breast Cancer Campaign is calling for funding organizations to reverse the decline in resources targeted towards breast cancer research, an improved and collaborative infrastructure to support breast cancer research, multidisciplinary collaboration and improved clinical trial design. We hope that breast cancer can be overcome by 2050, but this can only be achieved through collaboration with others. The actions that will make a difference have been identified and we must act now.

  13. Hypoxanthine enhances the cured meat taste.

    PubMed

    Ichimura, Sayaka; Nakamura, Yukinobu; Yoshida, Yuka; Hattori, Akihito

    2017-02-01

    We evaluated the enhancement of cured meat taste during maturation by sensory analysis. We focused on the heat-stable sarcoplasmic fraction (HSSF) to identify the factors related to cured meat taste. Because the dry matter of HSSF contained more than 30% nitrogen, nitrogen compounds such as free amino acids, small peptides and adenosine triphosphate-related compounds seemed to be the important components of HSSF. The samples cured with HSSF for 2 h exhibited the same taste profile as ones cured without HSSF for 168 h. Therefore, the changes in the amount and fractions of nitrogen compounds were examined in HSSF during incubation from 0 to 168 h. The concentration of hypoxanthine (Hx) gradually increased, while inosine-5'-monophosphate decreased during the incubation. The samples cured with pickles containing various concentrations of Hx were subjected to sensory analysis. The addition of Hx, in a dose-dependent fashion, enhanced cured meat taste by maturation for 2 h. It was concluded that Hx is essential for the enhancement of cured meat taste.

  14. Hypoxanthine enhances the cured meat taste

    PubMed Central

    Nakamura, Yukinobu; Yoshida, Yuka; Hattori, Akihito

    2016-01-01

    Abstract We evaluated the enhancement of cured meat taste during maturation by sensory analysis. We focused on the heat‐stable sarcoplasmic fraction (HSSF) to identify the factors related to cured meat taste. Because the dry matter of HSSF contained more than 30% nitrogen, nitrogen compounds such as free amino acids, small peptides and adenosine triphosphate‐related compounds seemed to be the important components of HSSF. The samples cured with HSSF for 2 h exhibited the same taste profile as ones cured without HSSF for 168 h. Therefore, the changes in the amount and fractions of nitrogen compounds were examined in HSSF during incubation from 0 to 168 h. The concentration of hypoxanthine (Hx) gradually increased, while inosine‐5′‐monophosphate decreased during the incubation. The samples cured with pickles containing various concentrations of Hx were subjected to sensory analysis. The addition of Hx, in a dose‐dependent fashion, enhanced cured meat taste by maturation for 2 h. It was concluded that Hx is essential for the enhancement of cured meat taste. PMID:27169902

  15. 7 CFR 29.3002 - Air-cured.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Air-cured. Tobacco cured under natural atmospheric conditions. Artificial heat is sometimes used to...-cured tobacco should not carry the odor of smoke or fumes resulting from the application of...

  16. 7 CFR 29.3002 - Air-cured.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Air-cured. Tobacco cured under natural atmospheric conditions. Artificial heat is sometimes used to...-cured tobacco should not carry the odor of smoke or fumes resulting from the application of...

  17. 7 CFR 29.3002 - Air-cured.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Air-cured. Tobacco cured under natural atmospheric conditions. Artificial heat is sometimes used to...-cured tobacco should not carry the odor of smoke or fumes resulting from the application of...

  18. 7 CFR 29.3002 - Air-cured.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Air-cured. Tobacco cured under natural atmospheric conditions. Artificial heat is sometimes used to...-cured tobacco should not carry the odor of smoke or fumes resulting from the application of...

  19. A study of the effects of curing and storage conditions on controlled release diphenhydramine HCl pellets coated with Eudragit NE30D.

    PubMed

    Lin, Angela Y; Muhammad, Nouman A; Pope, David; Augsburger, Larry L

    2003-08-01

    The objective of this study was to investigate the possible impacts of curing and storage conditions on dissolution of controlled release diphenhydramine HCl pellets coated with EUDRAGIT NE30D. The accumulative percentage of dissolved active drug was used as the response in three statistical experimental design studies: 32 full factorial, Box-Behnken and 2(3) designs. By only considering curing temperature and curing time, both factors were found to significantly affect the dissolution rate, but curing temperature had greater impact than curing time. When considering polymer coating level, curing temperature and curing time together, polymer coating level and curing temperature had important effects on dissolution rate, but curing time became insignificant among these three factors. The addition of the water-soluble additives hydroxypropyl methyl cellulose and mannitol made coating films less sensitive to curing, and there was little or no difference in their effect in the model studied. Lower levels of a water-insoluble additive (kaolin) had little impact on dissolution; however, when the level of water-insoluble additive increased, the coating film became more sensitive to curing, especially at the lower curing temperature of 30 degrees C.

  20. Plasma arc versus halogen light-curing of adhesive-precoated orthodontic brackets: a 12-month clinical study of bond failures.

    PubMed

    Cacciafesta, Vittorio; Sfondrini, Maria Francesca; Scribante, Andrea

    2004-08-01

    The purpose of this randomized clinical trial was to evaluate the performance of adhesive-precoated brackets cured with 2 different light-curing units (conventional halogen light and plasma arc light). Thirty patients treated with fixed appliances were included in the investigation. Each patient's mouth was divided by the split-mouth design into 4 quadrants. In 15 randomly selected patients, the maxillary left and mandibular right quadrants were cured with the halogen light, and the remaining quadrants were cured with the plasma arc light. In the other 15 patients, the quadrants were inverted. A total of 600 adhesive precoated stainless steel brackets were examined: 300 were cured with a conventional halogen light for 20 seconds, and the others were cured with the plasma arc light for 5 seconds. The number, cause, and date of bracket failures were recorded for each light-curing unit over 12 months. Statistical analysis was performed with the Fisher exact test, Kaplan-Meier survival estimates, and the log-rank test. No statistically significant differences in bond failure rates were found between the adhesive-precoated brackets cured with the halogen light and those cured with the plasma arc light; neither were any significant differences in performance found with each light-curing unit between the maxillary and mandibular arches. Plasma arc lights can be considered an advantageous alternative to conventional light curing, because they enable the clinician to reduce the curing time of adhesive-precoated orthodontic brackets without significantly affecting their bond failure rate.

  1. The curing of high-performance concrete

    NASA Astrophysics Data System (ADS)

    Meeks, Kenneth Wayne

    This dissertation describes the latest information, technology, and research on the curing of high performance concrete (HPC). Expanded somewhat beyond the scope of HPC, it examines the current body of knowledge on the effects of various curing regimes on concrete. The significance and importance of curing are discussed as well as the various definitions of HPC. The current curing requirements, standards, and criteria as proposed by ACI, as well as those of other countries, are reviewed and discussed. The current prescriptive curing requirements may not be applicable to high performance concrete. The research program reported in this dissertation looked at one approach to development of curing criteria for this relatively new class of concrete. The program applies some of the basic concepts of the methodology developed by the German researcher, H. K. Hilsdorf, to the curing of HPC with the objective to determine minimum curing durations for adequate strength development. The approach is to determine what fraction of the standard-cured 28-day strength has to be attained at the end of the curing period to assure that the design strength is attained in the interior of the member. An innovative direct tension test was developed to measure the strength at specific depths from the drying surface of small mortar cylinders (50 x 127 mm (2 x 5 in.)). Two mortar mixtures were investigated, w/c = 0.30 and w/c = 0.45, and three different moist curing regimes, 1-day, 3-day, and 7-day. Specimens were stored in two environmental chambers at 25sp°C, 50% RH; and 25sp°C, 70% RH, until testing at the age of 28 days. Direct tensile tests were conducted using steel disks epoxied to the ends of the specimens. Also, the penetration of the drying front was calculated from the drying data using porosity and degree of hydration relationships. The major observation from these tests was that adequate strength is attained in both mortar mixtures with only one day of moist curing. The drying

  2. One-step microwave foaming and curing

    NASA Technical Reports Server (NTRS)

    Gagliani, J.; Lee, R.; Sorathia, U. A. K.; Wilcoxson, A. L.

    1981-01-01

    Process that combines microwave foaming and curing of polyimide precursors in single step produces fire-resistant foam slabs of much larger volume than has previously been possible. By adding selected conductive fillers to powder precursors and by using high-power microwave oven, foam slabs with dimensions in excess of 61 by 61 by 7.6 cm are made. Typical foaming and curing and curing time is 35 minutes in microwave oven with additional 1 to 2 hour postcure in conventional oven.

  3. Acceleration of curing of resin composite at the bottom surface using slow-start curing methods.

    PubMed

    Yoshikawa, Takako; Morigami, Makoto; Sadr, Alireza; Tagami, Junji

    2013-01-01

    The aim of this study was to evaluate the effect of two slow-start curing methods on acceleration of the curing of resin composite specimens at the bottom surface. The light-cured resin composite was polymerized using one of three curing techniques: (1) 600 mW/cm(2) for 60 s, (2) 270 mW/cm(2) for 10 s+0-s interval+600 mW/cm(2) for 50 s, and (3) 270 mW/cm(2) for 10 s+5-s interval+600 mW/cm(2) for 50 s. After light curing, Knoop hardness number was measured at the top and bottom surfaces of the resin specimens. The slow-start curing method with the 5-s interval caused greater acceleration of curing of the resin composite at the bottom surface of the specimens than the slow-start curing method with the 0-s interval. The light-cured resin composite, which had increased contrast ratios during polymerization, showed acceleration of curing at the bottom surface.

  4. Visible light-curing unit.

    PubMed

    2002-10-01

    Ortholux XT is a high-intensity light source emitting filtered visible blue light in the 400- to 500-nanometer range for polymerization of visible-light-cured resins. The Ortholux handpiece comes with a portable power supply, a light-intensity check in the power supply, a spare lamp, an eyeshield and a mounting kit. The handpiece consists of a pistol grip with a thermoplastic housing that contains the light source, cooling fan, light guide receptacle (8- or 13-millimeter-diameter fused quartz lightguide), optical filter, light switch and timer switch. The timer is operator-selectable with options of five, 10, 15 and 20 seconds and an XT option of up to 600 seconds. The push-button switch allows for timer disruption and reactivation. 3M Unitek reported (3M Unitek, unpublished data submitted to the ADA, date not known) that the cooling fan generates noise below 43 decibels when the internal handpiece temperature is below 100 C. At 120 C, the fan speed increases, generating 52 dBA. The U.S. Air Force Dental Investigative Service reported that the cooling fan is extremely quiet. The light shuts off when it reaches 140 C. The light source is a 75-watt tungsten/halogen lamp. The handpiece weighs less than one pound. The power supply contains the built-in intensity meter that illuminates a green light-emitting diode when the tested light exceeds 400 milliwatts per square centimeter. The power cord is six feet in length. A built-in voltage regulator ensures a steady voltage supply to the unit.

  5. [Mineral water as a cure].

    PubMed

    Nocco, Priska Binz

    2008-01-01

    The treatment of diseases with mineral spring water belongs to the oldest medical therapies. The "remedy" mineral water is therefore of importance also within the pharmacy. The present pharmacy historical work examines the impact of the use of mineral waters, as well as of their dried components, as therapeutic agents in the 19th and early 20th centuries, i.e. from approx. 1810 to 1930, as well as the contributions given by pharmacists in the development and analysis of mineral water springs. Beside these aspects, the aim here is also to describe the role played by pharmacists in the production of artificial mineral water as well as in the sale and wholesale of natural and artificial mineral water. In the first part of this work the situation in Switzerland and its surrounding countries, such as Germany, France, Italy and Austria, is discussed. The second part contains a case-study of the particular situation in the Canton Tessin. It is known from the scientific literature published at that time that information on mineral water was frequently reported. Starting from the beginning of the 19th century the number of such publications increased tremendously. The major part of them were publications in scientific journals or contributions to medical and pharmaceutical manuals and reference books. In particular the spa-related literature, such as spa-guides, was of growing interest to a broad public. The inclusion of monographs into the Swiss, the Cantonal as well the foreign pharmacopoeias granted a legal frame for the mineral waters and their dried components. These works are of major importance from a pharmacy historical standpoint and represent a unique proof of historical evidence of the old medicinal drug heritage. The most frequently used therapies based on mineral waters were drinking and bath cures. Several diseases, particularly those of a chronic character, were treated with mineral waters. The positive influence of these cures on the recovery of the patients

  6. Social desirability in personality inventories: symptoms, diagnosis and prescribed cure.

    PubMed

    Bäckström, Martin; Björklund, Fredrik

    2013-04-01

    An analysis of social desirability in personality assessment is presented. Starting with the symptoms, Study 1 showed that mean ratings of graded personality items are moderately to strongly linearly related to social desirability (Self Deception, Impression formation, and the first Principal Component), suggesting that item popularity may be a useful heuristic tool for identifying items which elicit socially desirable responding. We diagnose the cause of socially desirable responding as an interaction between the evaluative content of the item and enhancement motivation in the rater. Study 2 introduced a possible cure; evaluative neutralization of items. To test the feasibility of the method lay psychometricians (undergraduates) reformulated existing personality test items according to written instructions. The new items were indeed lower in social desirability while essentially retaining the five factor structure and reliability of the inventory. We conclude that although neutralization is no miracle cure, it is simple and has beneficial effects.

  7. Inelastic micromechanics of curing stresses in composites

    NASA Technical Reports Server (NTRS)

    Foye, R. L.

    1975-01-01

    The combined finite element/laminate analysis method is used to study the thermal curing stresses in composite materials with a nonlinearly elastic matrix subject to creep. The application of this analysis to boron/epoxy composites shows that curing stress levels in the laminate are of sufficient magnitude to cause widespread yielding in the matrix. The stress levels, based on the creep analysis of a typical laminate cure cycle, indicate that the residual stresses can vary from 80 to 100% of the residual stress estimates based on linear thermoelastic analysis. It is shown that there is virtually no change in the static longitudinal or shear response of unidirectional and cross-ply boron/epoxy laminates as a result of curing stresses. Results of a series of constant-stress, high temperature creep tests are presented.

  8. Curing of Furfuryl Alcohol-Impregnated Parts

    NASA Technical Reports Server (NTRS)

    Lawton, J. W.; Brayden, T. H.

    1983-01-01

    Delamination problem in reinforced carbon/carbon parts impregnated with oxalic acid-catalyzed furfuryl alcohol overcome by instituting two additional quality-control tests on alcohol and by changing curing conditions.

  9. New advanced shotcrete admixtures: Internal curing

    SciTech Connect

    Melbye, T.A.

    1995-12-31

    Tunnels and other underground construction projects have one of the worst curing conditions due to the ventilation that blows continuously dry (cold or hot) air into the tunnel. It can be compared with concrete exposed to a windy area. One would think that tunnels have ideal curing conditions with high humidity (water leakage), no wind and no sun exposure. However, this is not the case. MBT has developed a new system for more efficient and secure curing of wet shotcrete, repair mortars as well as concrete. Internal curing means that a special admixture is added to the concrete/mortar during batching as a normal admixture. This admixture produces an internal barrier in the shotcrete/concrete which secures safer hydration and better chemical resistance than the application of conventional curing agents. The benefits resulting from the new technology are impressive: The time consuming application and, in the case of various shotcrete layers, removal of curing agents are no longer necessary; curing is guaranteed from the very beginning of hydration; and there is no negative influence on bonding between layers. As a consequence of th is optimum curing effect, all other shotcrete characteristics are improved: density, final strengths, freeze/thaw and chemical resistances, watertightness, less cracking and shrinkage. In addition, MEYCO TCC 735 also improves pumpability and workability of shotcrete, even with low-grade aggregates. It particularly improves the pumpability of steel fiber reinforced shotcrete mixes. In combination with the MEYCO TCC system it contrives to even increase the beneficial effects of the slump killing system by further improving fiber orientation, reducing fiber rebound and thus raising toughness values.

  10. Tracking Polymer Cure Via Embedded Optical Fibers

    NASA Technical Reports Server (NTRS)

    Dean, David L.; Davidson, T. Fred

    1993-01-01

    Fourier-transform infrared spectroscopy applied in interior of specimen of material by bringing infrared light through specimen in optical fiber. Light interacts with material via evanescent-wave effect. Spectra obtained in this way at various times during curing process also combined with data from ultrasonic, thermographic, and dielectric-impedance monitoring, and other measurement techniques to obtain more complete characterization of progress of curing process.

  11. The cure of cancer: a European perspective.

    PubMed

    Francisci, Silvia; Capocaccia, Riccardo; Grande, Enrico; Santaquilani, Mariano; Simonetti, Arianna; Allemani, Claudia; Gatta, Gemma; Sant, Milena; Zigon, Giulia; Bray, Freddie; Janssen-Heijnen, Maryska

    2009-04-01

    Cancer survival analyses based on cancer registry data do not provide direct information on the main aim of cancer treatment, the cure of the patient. In fact, classic survival indicators do not distinguish between patients who are cured, and patients who will die of their disease and in whom prolongation of survival is the main objective of treatment. In this study, we applied parametric cure models to the cancer incidence and follow-up data provided by 49 EUROCARE-4 (European Cancer Registry-based study, fourth edition) cancer registries, with the aims of providing additional insights into the survival of European cancer patients diagnosed from 1988 to 1999, and of investigating between-population differences. Between-country estimates the proportion of cured patients varied from about 4-13% for lung cancer, from 9% to 30% for stomach cancer, from 25% to 49% for colon and rectum cancer, and from 55% to 73% for breast cancer. For all cancers combined, estimates varied between 21% and 47% in men, and 38% and 59% in women and were influenced by the distribution of cases by cancer site. Countries with high proportions of cured and long fatal case survival times for all cancers combined were characterised by generally favourable case mix. For the European pool of cases both the proportion of cured and the survival time of fatal cases were associated with age, and increased from the early to the latest diagnosis period. The increases over time in the proportions of Europeans estimated cured of lung, stomach and colon and rectum cancers are noteworthy and suggest genuine progress in cancer control. The proportion of cured of all cancers combined is a useful general indicator of cancer control as it reflects progress in diagnosis and treatment, as well as success in the prevention of rapidly fatal cancers.

  12. Energy curable compositions having improved cure speeds

    DOEpatents

    Halm, Leo W.

    1993-01-01

    A composition and method provide improved physical properties and cure speed of polyurethane precursors, with or without free radical polymerizable monomers or oligomers present, by use of a two component catalyst system. The resin blend can be activated with a latent organometallic catalyst combined with an organic peroxide which can be a hydroperoxide or an acyl peroxide to decrease the cure time while increasing the break energy and tangent modulus of the system.

  13. Energy curable compositions having improved cure speeds

    DOEpatents

    Halm, L.W.

    1993-05-18

    The composition and method provide improved physical properties and cure speed of polyurethane precursors, with or without free radical polymerizable monomers or oligomers present, by use of a two component catalyst system. The resin blend can be activated with a latent organometallic catalyst combined with an organic peroxide which can be a hydroperoxide or an acyl peroxide to decrease the cure time while increasing the break energy and tangent modulus of the system.

  14. Radiation Curing of Natural Fiber Composite

    NASA Astrophysics Data System (ADS)

    Liu, Xueyuan

    This research is a study of the process and feasibility of applying UV to cure natural and recycled fiber composites. The influence of HEMA on the water absorption and mechanical properties of the composites also investigated. Results show that UV curing is feasible in the manufacture of natural and recycle fiber composites. HEMA significantly improved the water resistance of the composite. HEMA-treated natural and recycled fiber composites have better bending strength after water impregnation, than non-treated composites.

  15. Anomalous Behavior of Cured Epoxy Resins: Density at Room Temperature versus Time and Temperature of Cure

    DTIC Science & Technology

    1988-07-01

    density (at 250 C) of a OGEBA epoxy resin cured with phthalic acid anhydride increased with time of cure at a single cure temperature, reached a maximum...time to vitrification to eventually form a glass. A more appropriate time indicator for the formation of glassy-state material in principle is that... enthalpy relaxation immediately above the assigned Tg, is typical of all slow-cooled, and also of fast-cooled specimens which had vitrified during

  16. High Power UV LED Industrial Curing Systems

    SciTech Connect

    Karlicek, Robert, F., Jr; Sargent, Robert

    2012-05-14

    UV curing is a green technology that is largely underutilized because UV radiation sources like Hg Lamps are unreliable and difficult to use. High Power UV LEDs are now efficient enough to replace Hg Lamps, and offer significantly improved performance relative to Hg Lamps. In this study, a modular, scalable high power UV LED curing system was designed and tested, performing well in industrial coating evaluations. In order to achieve mechanical form factors similar to commercial Hg Lamp systems, a new patent pending design was employed enabling high irradiance at long working distances. While high power UV LEDs are currently only available at longer UVA wavelengths, rapid progress on UVC LEDs and the development of new formulations designed specifically for use with UV LED sources will converge to drive more rapid adoption of UV curing technology. An assessment of the environmental impact of replacing Hg Lamp systems with UV LED systems was performed. Since UV curing is used in only a small portion of the industrial printing, painting and coating markets, the ease of use of UV LED systems should increase the use of UV curing technology. Even a small penetration of the significant number of industrial applications still using oven curing and drying will lead to significant reductions in energy consumption and reductions in the emission of green house gases and solvent emissions.

  17. Assessing the fit of parametric cure models.

    PubMed

    Wileyto, E Paul; Li, Yimei; Chen, Jinbo; Heitjan, Daniel F

    2013-04-01

    Survival data can contain an unknown fraction of subjects who are "cured" in the sense of not being at risk of failure. We describe such data with cure-mixture models, which separately model cure status and the hazard of failure among non-cured subjects. No diagnostic currently exists for evaluating the fit of such models; the popular Schoenfeld residual (Schoenfeld, 1982. Partial residuals for the proportional hazards regression-model. Biometrika 69, 239-241) is not applicable to data with cures. In this article, we propose a pseudo-residual, modeled on Schoenfeld's, to assess the fit of the survival regression in the non-cured fraction. Unlike Schoenfeld's approach, which tests the validity of the proportional hazards (PH) assumption, our method uses the full hazard and is thus also applicable to non-PH models. We derive the asymptotic distribution of the residuals and evaluate their performance by simulation in a range of parametric models. We apply our approach to data from a smoking cessation drug trial.

  18. Efficient composite fabrication using electron-beam rapidly cured polymers engineered for several manufacturing processes

    SciTech Connect

    Walton, T.C.; Crivello, J.V.

    1995-10-01

    Low cost, efficiently processed ultra high specific strength and stiffness graphite fiber reinforced polymeric composite materials are of great interest to commercial transportation, construction and aerospace industries for use in various components with enhanced degrees of weight reduction, corrosion/erosion resistance and fatigue resistance. 10 MeV Electron Beam cure processing has been found to increase the cure rate by an order of magnitude over thermally cured systems yet provide less molded in stresses and high T{sub g}s. However, a limited range of resins are available which are easily processed with low shrinkage and with performance properties equal or exceeding those of state of the art toughened epoxies and BMI`s. The technology, introduced by an academia-industry partnership sparked by Langley Research Center utilizes a cost effective, rapid curing polymeric composite processing technique which effectively reduces the need for expensive tooling and energy inefficient autoclave processing and can cure the laminate in seconds (compared to hours for thermal curing) in ambient or sub-ambient conditions. The process is based on electron beam (E-Beam) curing of a new series of (65 to 1,000,000 cPs.) specially formulated resins that have been shown to exhibit excellent mechanical and physical properties once cured. Fabrication processes utilizing these specially formulated and newly commercialized resins, (e.g. including Vacuum Assist Resin Transfer molding (VARTM), vacuum bag prepreg layup, pultrusion and filament winding grades) are engineered to cure with low shrinkage, provide excellent mechanical properties, be processed solventless (environmentally friendly) and are inherently non toxic.

  19. 7 CFR 29.2269 - Fire-cured.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Fire-cured. 29.2269 Section 29.2269 Agriculture... INSPECTION Standards Official Standard Grades for Virginia Fire-Cured Tobacco (u.s. Type 21) § 29.2269 Fire-cured. Tobacco cured under artificial atmospheric conditions by the use of open fires from which...

  20. 7 CFR 29.2269 - Fire-cured.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false Fire-cured. 29.2269 Section 29.2269 Agriculture... INSPECTION Standards Official Standard Grades for Virginia Fire-Cured Tobacco (u.s. Type 21) § 29.2269 Fire-cured. Tobacco cured under artificial atmospheric conditions by the use of open fires from which...

  1. 7 CFR 29.2269 - Fire-cured.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Fire-cured. 29.2269 Section 29.2269 Agriculture... INSPECTION Standards Official Standard Grades for Virginia Fire-Cured Tobacco (u.s. Type 21) § 29.2269 Fire-cured. Tobacco cured under artificial atmospheric conditions by the use of open fires from which...

  2. 7 CFR 29.2269 - Fire-cured.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false Fire-cured. 29.2269 Section 29.2269 Agriculture... INSPECTION Standards Official Standard Grades for Virginia Fire-Cured Tobacco (u.s. Type 21) § 29.2269 Fire-cured. Tobacco cured under artificial atmospheric conditions by the use of open fires from which...

  3. 7 CFR 29.2269 - Fire-cured.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false Fire-cured. 29.2269 Section 29.2269 Agriculture... INSPECTION Standards Official Standard Grades for Virginia Fire-Cured Tobacco (u.s. Type 21) § 29.2269 Fire-cured. Tobacco cured under artificial atmospheric conditions by the use of open fires from which...

  4. [Progress in endogenous plasmid curing of bacteria--a review].

    PubMed

    Feng, Jun; Zhang, Wei; Song, Cunjiang

    2013-11-04

    To investigate the functions of the bacteria endogenous plasmid, which include bacterial drug resistance, symbiosis, capsular formation and heavy metal resistance, the endogenous plasmid needs to be cured first. We reviewed physical, chemical and molecular biological methods of endogenous plasmid curing, clarified the curing principles. The prospective of research on plasmid curing was also discussed, based on our own studies.

  5. 7 CFR 29.3502 - Air-cured.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Air-cured. 29.3502 Section 29.3502 Agriculture... INSPECTION Standards Official Standard Grades for Dark Air-Cured Tobacco (u.s. Types 35, 36, 37 and Foreign Type 95) § 29.3502 Air-cured. Tobacco cured under natural atmospheric conditions without the use...

  6. 7 CFR 29.6002 - Air-cured.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Air-cured. 29.6002 Section 29.6002 Agriculture... INSPECTION Standards Definitions § 29.6002 Air-cured. Tobacco cured under natural atmospheric conditions..., pole-burn, and shed-burn in damp weather. Air-cured tobacco should not carry the odor of smoke or...

  7. 7 CFR 29.6002 - Air-cured.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Air-cured. 29.6002 Section 29.6002 Agriculture... INSPECTION Standards Definitions § 29.6002 Air-cured. Tobacco cured under natural atmospheric conditions..., pole-burn, and shed-burn in damp weather. Air-cured tobacco should not carry the odor of smoke or...

  8. 7 CFR 58.412 - Coolers or curing rooms.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Coolers or curing rooms. 58.412 Section 58.412... Specifications for Dairy Plants Approved for USDA Inspection and Grading Service 1 Rooms and Compartments § 58.412 Coolers or curing rooms. Coolers or curing rooms where cheese is held for curing or storage...

  9. Influence of curing temperature on cement hydration and mechanical strength development of fly ash mortars

    SciTech Connect

    Maltais, Y.; Marchand, J.

    1997-07-01

    The influence of fly ash and curing temperature on cement hydration and compressive strength development of mortars was investigated. Test parameters included type of fly ash (two different Class F fly ashes were tested), the level of cement replacement (10, 20 and 30% by mass), and curing temperature (20 C and 40 C). The mortar physical and microstructural properties were determined by means of thermal analyses, compressive strength measurements and SEM observations. Test results confirm that fly ash tends to increase significantly the rate of cement hydration at early age. Data also demonstrate that an elevation of the curing temperature reduces the long-term compressive strength of the reference mortar mixture. In contrast, an increase of the curing temperature seems to have no detrimental effect on the long-term compressive strength of the fly ash mixtures.

  10. Production implementation of fully automated, closed loop cure control for advanced composite structures

    NASA Astrophysics Data System (ADS)

    Johnson, Sean A.; Roberts, Nancy K.

    Economic of advanced composite part production requires development and use of the most aggressive cure cycles possible without sacrificing quality. As cure cycles are shortened and heating rates increase, tolerance windows for process parameters become increasingly narrow. These factors are intensified by condensation curing systems which generate large amounts of volatiles. Management of the situation requires fully automated, closed loop process control and a fundamental understanding of the material system used for the application. No turnkey system for this application is currently available. General Dynamics Pomona Division (GD/PD) has developed an integrated closed loop control system which is now being proofed in production. Realization of this system will enable cure time reductions of nearly 50 percent, while increasing yield and maintaining quality.

  11. DSC and curing kinetics study of epoxy grouting diluted with furfural -acetone slurry

    NASA Astrophysics Data System (ADS)

    Yin, H.; Sun, D. W.; Li, B.; Liu, Y. T.; Ran, Q. P.; Liu, J. P.

    2016-07-01

    The use of furfural-acetone slurry as active diluents of Bisphenol-A epoxy resin (DGEBA) groutings has been studied by dynamic and non-isothermal DSC for the first time. Curing kinetics study was investigated by non-isothermal differential scanning calorimetries at different heating rates. Activation enery (Ea) was calculated based on Kissinger and Ozawa Methods, and the results showed that Ea increased from 58.87 to 71.13KJ/mol after the diluents were added. The furfural-acetone epoxy matrix could cure completely at the theoretical curing temperature of 365.8K and the curing time of 139mins, which were determined by the kinetic model parameters.

  12. Characterization of cure in model photocrosslinking acrylate systems: Relationships among tensile properties, Tg and ultraviolet dose

    SciTech Connect

    Rakas, M.A.

    1996-10-01

    The extent of cure of a thermosetting polymer is governed largely by polymerization kinetics and the difference between the polymerization temperature and the material`s ultimate glass transition temperature (Tg). For prepolymers which cure when exposed to ultraviolet (UV) radiation, other factors which strongly determine the extent of cure are the UV intensity and exposure time, and the interrelationship between the optical absorbance of the photoinitiator (PI) and the rate of formation of excited state PI radicals. Beers` Law can be used to understand the relationship between the PI`s molar absorptivity, its concentration, and adhesive film thickness. Many adhesives users are more concerned with bulk properties such as tensile modulus and Tg rather than a numerical measurement of degree of cure. Therefore, this research employed model acrylate formulations and determined changes in tensile properties and Tg as a function of film thickness and UV dose. These results enabled correlation of bulk and photoinitiator properties.

  13. Effect of curing agent and temperature on the rheological behavior of epoxy resin systems.

    PubMed

    Zhao, Chenhui; Zhang, Guangcheng; Zhao, Lei

    2012-07-17

    The effect of curing agent (6610) content and temperature on the rheological behavior of the epoxy resin CYD-128 was studied by DSC analysis and viscosity experiments. The results show that the resin system meets the requirements of processing technology. A complete reaction occurs when the curing agent content (40 parts per hundred resin, phr) is a little higher than the theoretical value (33.33 phr), while the degree of reaction of the resin system is reduced when the curing agent content is lower (25.00 phr) than theoretical value. However, excessive curing agent (50.00 phr) results in a lower reaction rate. Curing agent content has little influence on gel time when curing agent content exceeded 33.33 phr and the temperature was less than 70 °C. The isothermal viscosity-time curves shift towards the -x axis when the temperature rises from 50 °C to 80 °C. Meanwhile, higher temperature results in higher reaction rates.

  14. Clinical trial comparing plasma arc and conventional halogen curing lights for orthodontic bonding.

    PubMed

    Manzo, Bruno; Liistro, Giuseppe; De Clerck, Hugo

    2004-01-01

    The purpose of this clinical trial was to evaluate the reliability and time saved with a plasma arc curing unit (Apollo 95E, Dental/Medical Diagnostic Systems, Woodland Hills, Calif) compared with a conventional curing unit (Ortholux XL 3000, 3M Unitek, St Paul, Minn) for direct bracket bonding with resin adhesive. Forty-five patients were involved in the study, and 608 brackets were bonded in a contralateral quadrant pattern. The patients were followed for a mean (+/- standard deviation) period of 11 +/- 3.2 months. Survival analysis was carried out to compare the failure rate for the 2 techniques. The time required for bonding with each technique was also recorded. The mean survival time was 399 days, and there were no significant differences in survival time between the 2 bonding methods. Twelve bonding failures were reported with each technique. The curing time per bracket was significantly reduced with the plasma curing light compared with a conventional curing unit (65 +/- 19 vs 82 +/- 31 seconds). The plasma arc curing light can save chair-time without affecting the bonding failure rate.

  15. Infrared curing simulations of liquid composites molding

    NASA Astrophysics Data System (ADS)

    Nakouzi, S.; Pancrace, J.; Schmidt, F. M.; Le Maoult, Y.; Berthet, F.

    2011-05-01

    Infrared radiation is an effective energy source to cure thermosetting polymers. Its usage is expected to reduce curing time in comparison with thermal heating and mold thermally regulated. In addition, because of the polymerization mechanism and instant on-off control of this power, an improvement in the final properties of the material is also expected. In this paper, we studied the infrared interaction with carbon (or glass) fibers reinforced epoxy matrix, where Liquid resin infusion (LRI) is used to manufacture the composite. Temperature of the composite is a key parameter that affects its mechanical properties and is controlled by the infrared emitters and the exothermic heat released from the polymerization. Radiative heat flux is computed using the in-lab developed software RAYHEAT. Then, the heat flux (or absorbed energy for glass fibers) is exported to the finite element based program COMSOLMULTIPHYSICS where heat balance equation is solved. This equation is coupled with the exothermic heat released during the curing process in order to predict the composite temperature versus time and degree of cure. Numerical simulations will be performed on planar parts (sheet shape) as well as curvilinear shapes. Experimental validations of the infrared curing carbon (glass)-epoxy composite system are presented in this paper Sheet surface temperature distribution are measured thanks to infrared camera. Kinetic parameters were estimated from differential scanning calorimeter (DSC) experimental data.

  16. Infrared curing simulations of liquid composites molding

    SciTech Connect

    Nakouzi, S.; Pancrace, J.; Schmidt, F. M.; Le Maoult, Y.; Berthet, F.

    2011-05-04

    Infrared radiation is an effective energy source to cure thermosetting polymers. Its usage is expected to reduce curing time in comparison with thermal heating and mold thermally regulated. In addition, because of the polymerization mechanism and instant on-off control of this power, an improvement in the final properties of the material is also expected. In this paper, we studied the infrared interaction with carbon (or glass) fibers reinforced epoxy matrix, where Liquid resin infusion (LRI) is used to manufacture the composite. Temperature of the composite is a key parameter that affects its mechanical properties and is controlled by the infrared emitters and the exothermic heat released from the polymerization. Radiative heat flux is computed using the in-lab developed software RAYHEAT. Then, the heat flux (or absorbed energy for glass fibers) is exported to the finite element based program COMSOLMULTIPHYSICS where heat balance equation is solved. This equation is coupled with the exothermic heat released during the curing process in order to predict the composite temperature versus time and degree of cure. Numerical simulations will be performed on planar parts (sheet shape) as well as curvilinear shapes. Experimental validations of the infrared curing carbon (glass)-epoxy composite system are presented in this paper Sheet surface temperature distribution are measured thanks to infrared camera. Kinetic parameters were estimated from differential scanning calorimeter (DSC) experimental data.

  17. Cured products from different animal species.

    PubMed

    Paleari, Maria Antonietta; Moretti, Vittorio Maria; Beretta, Giuseppe; Mentasti, Tiziana; Bersani, Carla

    2003-04-01

    An assessment was made of the proximate composition, pH and a(W) of raw beef, horsemeat and the meat of wild boar, deer and goat. The same assessment, together with one of fatty acids, cholesterol and free amino acids, was made of the same meats as cured products. The raw meat of the different animal species was found to have a reduced lipid, but high protein content. The cured meat of the horse and wild boar had low saturated fatty acid levels; the wild boar, goatmeat and beef were quantitatively similar with regard to monounsaturated fatty acids (MUFA) while in the horsemeat the polyunsaturated fatty acids (PUFA) were more raised, at an intermediate level in deer and extremely reduced in the beef final product. The cholesterol content in the cured product was markedly reduced in the horsemeat. The free amino acids content in the cured deer, wild boar and goat meat was more elevated, than in beef and horse cured meat.

  18. Evaluation of heat-cured resin bases following the addition of denture teeth using a second heat cure.

    PubMed

    Polukoshko, K M; Brudvik, J S; Nicholls, J I; Smith, D E

    1992-04-01

    This study compared heat-cured acrylic resin denture baseplate distortions following a second heat cure used to add the denture teeth. The second heat cure was done with three different water-bath curing temperatures. The distortions were evaluated in three planes by use of a measuring microscope. Recorded distortions were not clinically significant.

  19. Bond strengths of lingual orthodontic brackets bonded with light-cured composite resins cured by transillumination.

    PubMed

    King, L; Smith, R T; Wendt, S L; Behrents, R G

    1987-04-01

    A method of curing light-cured composite resins by transillumination to cement acid-etched fixed partial dentures was adapted to bond solid mesh-backed lingual orthodontic brackets. Results of this investigation showed that the bond strengths of the orthodontic brackets bonded with light-cured composite resins were significantly less (P less than 0.05) than the bond strengths of the orthodontic brackets cemented with traditional adhesives and orthodontic composite resins. Notwithstanding, the bond strengths achieved with the transilluminated light-cured composite resins should be adequate to withstand the forces of mastication and orthodontic movements. There was no correlation of bond strengths of the brackets cemented with the transilluminated light-cured composite resins when compared to the faciolingual widths of the teeth.

  20. Light curing time reduction: in vitro evaluation of new intensive light-emitting diode curing units.

    PubMed

    Mavropoulos, A; Staudt, C B; Kiliaridis, S; Krejci, I

    2005-08-01

    The aim of the present in vitro study was to establish the minimum necessary curing time to bond stainless steel brackets (Mini Diamond Twin) using new, intensive, light-emitting diode (LED) curing units. Seventy-five bovine primary incisors were divided into five equal groups. A standard light curing adhesive (Transbond XT) was used to bond the stainless steel brackets using different lamps and curing times. Two groups were bonded using an intensive LED curing lamp (Ortholux LED) for 5 and 10 seconds. Two more groups were bonded using another intensive LED curing device (Ultra-Lume LED 5) also for 5 and 10 seconds. Finally, a high-output halogen lamp (Optilux 501) was used for 40 seconds to bond the final group, which served as a positive control. All teeth were fixed in hard acrylic and stored for 24 hours in water at 37 degrees C. Shear bond strength (SBS) was measured using an Instron testing machine. Weibull distribution and analysis of variance were used to test for significant differences. The SBS values obtained were significantly different between groups (P < 0.001). When used for 10 seconds, the intensive LED curing units achieved sufficient SBS, comparable with the control. In contrast, 5 seconds resulted in significantly lower SBS. The adhesive remnant index (ARI) was not significantly affected.A curing time of 10 seconds was found to be sufficient to bond metallic brackets to incisors using intensive LED curing units. These new, comparatively inexpensive, curing lamps seem to be an advantageous alternative to conventional halogen lamps for bonding orthodontic brackets.

  1. Synthesis and cure characterization of high temperature polymers for aerospace applications

    NASA Astrophysics Data System (ADS)

    Li, Yuntao

    The E-beam curable BMI resin systems and phenylethynyl terminated AFR-PEPA-4 oligomer together with an imide model compound N-phenyl-[4-(phenylethynyl) phthalimide] were synthesized and characterized. E-beam exposure cannot propagate the polymerization of BMI system until the temperature goes up to 100°C. However, a small amount of oligomers may be generated from solid-state cure reaction under low E-beam intensity radiation. Higher intensity E beam at 40 kGy per pass can give above 75% reaction conversion of BMI with thermal cure mechanism involved. NVP is a good reactive diluent for BMI resin. The cure extents of BMI/NVP increase with the increase of the dosage and applied dosage per pass. The reaction rate is much higher at the beginning of the E-beam cure and slows down after 2 dose passes due to diffusion control. Free radical initiator dicumyl peroxide can accelerate the reaction rate at the beginning of E-beam cure reaction but doesn't affect final cure conversion very much. According to the results from FT-IR, 200 kGy total dosage E-beam exposure at 10 kGy per pass can give 70% reaction conversion of BMI/NVP with the temperature rise no more than 50°C. The product has a Tg of 180°C. The predicted ultimate Tg of cured AFR-PEPA-4 polyimide is found to be 437.2°C by simulation of DSC Tg as a function of cure. The activation energy of thermal cure reaction of AFR-PEPA-4 oligomer is 142.6 +/- 10.0 kJ/mol with the kinetic order of 1 when the reaction conversion is less than 80%. The kinetics analysis of the thermal cure of N-phenyl-[4-(phenylethynyl) phthalimide] was determined by FT-IR spectroscopy by following the absorbance of the phenylethynyl triple bond and conjugated bonds. The thermal crosslinking of N-phenyl-[4-(phenylethynyl) phthalimide] through phenylethynyl addition reaction has a reaction order of 0.95 and an activation energy of 173.5 +/- 8.2 kJ/mol. The conjugated bond addition reactions have a lower reaction order of 0.94 and lower activation

  2. Lower-curing-temperature PMR polyimides

    NASA Technical Reports Server (NTRS)

    Serafini, T. T.; Delvigs, P.; Vannucci, R. D.

    1981-01-01

    Studies were performed to achieve a lower-curing-temperature PMR polyimide. The use of m-aminostyrene as the end-cap instead of the monoalkyl ester of 5-normbornene-2,3 dicarboxylic acid was investigated in typical PMR formulations. Model compound studies were also performed. Differential scanning calorimetry studies were performed on model compounds and neat resins to establish their melting and curing characteristics. The elevated temperature weight loss characteristics of neat resins and graphite fiber composites were determined. The room temperature and short-time 260 C (500 F) mechanical properties of the composites were also determined. The use of m-aminostyrene end-caps reduced the final cure temperature of PMR resins by about 55 C (100 F), but the composites prepared with these resins are limited to use temperatures of about 260 C (500 F).

  3. Integrative physicians and an herbal cancer "cure".

    PubMed

    Ben-Arye, Eran; Rosenberg, Shoshana Keren; Samuels, Noah

    2016-08-01

    Oncologists are frequently asked about herbal remedies claiming to "cure" cancer, or at least delay its progression. While complementary and integrative medicine (CIM) should be aimed primarily at improving quality-of-life (QOL) related concerns, "wonder cures" are part of an alternative health belief model providing hope for a "miracle" where conventional treatment has failed. We describe a physician with extensive small-cell lung cancer (SCLC) undergoing chemotherapy, with significant toxicities and impaired daily function. He had come for an integrative physician (IP) consultation, provided by a medical doctor dually trained in CIM and supportive cancer care, taking place in a conventional supportive cancer care service. We describe the IP consultation in general and regarding an herbal remedy which was being promoted as a "cure" for cancer. The subsequent patient-tailored CIM treatment process, in which patients receive evidence-based guidance on treatments which address QOL-related concerns, are presented.

  4. Cure-in-place process for seals

    DOEpatents

    Hirasuna, Alan R.

    1981-01-01

    A cure-in-place process which allows a rubber seal element to be deformed to its service configuration before it is cross-linked and, hence, is a plastic and does not build up internal stress as a result of the deformation. This provides maximum residual strength to resist the differential pressure. Furthermore, the process allows use of high modulus formulations of the rubber seal element which would otherwise crack if cured and then deformed to its service configuration, resulting in a seal which has better gap bridging capability. Basically, the process involves positioning an uncured seal element in place, deforming it to its service configuration, heating the seal element, curing it in place, and then fully seating the seal.

  5. Crime, criminals, and cures: medical model revisited.

    PubMed

    Sampson, R J

    2000-06-01

    David Lykken's target article assesses the causes of crime and advocates a controversial "cure"--parental licensure. Although Lykken gets many of the facts about criminals right, ultimately the disease metaphor breaks down. Crime requires three things--motivated offenders ("criminals"), suitable targets or victims, and the absence of capable guardians to prevent the act. Typical of medical model approaches, failure to consider the convergence in time and space of the three necessary elements for crime results in a misdiagnosis. In this invited commentary, I briefly note three reasons why Lykken's cure, along with the medical model in general, is unlikely to bear fruit.

  6. Prevent and cure disuse bone loss

    NASA Technical Reports Server (NTRS)

    Jee, Webster S. S.

    1994-01-01

    Anabolic agents like parathyroid hormone and postagladin E-like substances were studied in dogs and rats to determine their effectiveness in the prevention and cure of bone loss due to immobilization. It was determined that postagladin E2 administration prevented immobilization while at the same time it added extra bone in a dose responsive manner. Although bone mass returns, poor trabecular architecture remains after normal ambulation recovery from immobilization. Disuse related bone loss and poor trabecular architecture were cured by post-immobilization postagladin E2 treatment.

  7. Chiropractor charged with claiming HIV cure.

    PubMed

    1999-07-23

    The Missouri Board of Chiropractic Examiners will decide later this year if [name removed]' license should be revoked or suspended because [name removed] allegedly told an HIV-positive patient that he had been cured. [Name removed] denies claiming that the patient was cured by his Interro machine. The patient claims he and his wife then decided to have children. The mother gave birth in 1992, and although the infant is not infected, the mother is. The patient's mother-in-law testified that [name removed] had assured her that the patient's virus had been absolutely eradicated by his treatments.

  8. The mechanisms of cure in psychoanalysis.

    PubMed

    Lander, Rómulo

    2007-01-01

    The author considers the theoretical contributions of Lacan and Bion in relation to therapeutic action or the mechanisms of the cure. Whereas Bion felt that the analysand should ultimately experience transformation in O, Lacan described the analysand's goal as not to give in to one's desire or to be one's self. The author distinguishes among various types of neurotic and psychotic structures in discussing the limits of the cure, noting that the analyst's acts--as well as his words--can function as analytic interpretations. Lacan's theories of jouissance, the sexual phantom, identification with the analytic function, and post-analytic effects are also discussed.

  9. Curing mechanism of flexible aqueous polymeric coatings.

    PubMed

    Irfan, Muhammad; Ahmed, Abid Riaz; Dashevskiy, Andriy; Kolter, Karl; Bodmeier, Roland

    2017-02-25

    The objective of this study was to explain curing phenomena for pellets coated with a flexible polymeric coating based on poly(vinyl acetate) (Kollicoat(®) SR 30D) with regard to the effect of starter cores, thickness of drug layer, adhesion of coating to drug-layered-cores as well as coating properties. In addition, appropriate approaches to eliminate the curing effect were identified. Sugar or MCC cores were layered with the model drugs carbamazepine, theophylline, propranolol HCl, tramadol HCl and metoprolol HCl using HPMC (5 or 25% w/w, based on drug) as a binder. Drug-layered pellets were coated with Kollicoat(®) SR 30D in a fluidized bed coater using TEC (10% w/w) as plasticizer and talc (35-100% w/w) as anti-tacking agent. Drug release, pellet properties (morphology, water uptake-weight loss and osmolality) and adhesion of the coating to the drug layer were investigated as a function of curing at 60 °C or 60 °C/75% RH for 24 h. The film formation of the aqueous dispersion of Kollicoat(®) SR 30D was complete, and therefore, a strong curing effect (decrease in drug release) at elevated temperature and humidity (60 °C/75% RH) could not be explained by the well-known hydroplasticization and the further gradual coalescence of the colloidal polymer particles. According to the provided mechanistic explanation, the observed curing effect was associated with 1) high flexibility of coating, 2) adhesion between coating and drug layer, 3) water retaining properties of the drug layer, and 4) osmotically active cores. Unwanted curing effects could be minimized/eliminated by the addition of talc or/and pore-forming water soluble polymers in the coating, increasing binder amount or applying an intermediate coating, by increasing the thickness of drug layer or using non-osmotic cores. A new insight into curing phenomena mainly associated with the adhesion between drug layer and coating was provided. Appropriate approaches to avoid unwanted curing effect were identified.

  10. FTIR Monitoring Of Curing Of Composites

    NASA Technical Reports Server (NTRS)

    Druy, Mark A.; Stevenson, William A.; Young, Philip R.

    1990-01-01

    Infrared-sensing optical fiber system developed to monitor principal infrared absorption bands resulting from vibrations of atoms and molecules as chemical bonds form when resin cured. System monitors resin chemistry more directly. Used to obtain Fourier transform infrared (FTIR) spectrum from graphite fiber/polyimide matrix resin prepreg. Embedded fiber optic FTIR sensor used to indicate state of cure of thermosetting composite material. Developed primarily to improve quality of advanced composites, many additional potential applications exist because principal of operation applicable to all organic materials and most inorganic gases. Includes monitoring integrities of composite materials in service, remote sensing of hazardous materials, and examination of processes in industrial reactors and furnaces.

  11. Residual monomer leaching from chemically cured and visible light-cured orthodontic adhesives.

    PubMed

    Eliades, T; Eliades, G; Brantley, W A; Johnston, W M

    1995-09-01

    The objective of this study was to quantify the amount of residual monomer leached from chemically cured and visible light-cured orthodontic adhesives based on Bis-GMA/TEGDMA monomers, when bonded to ceramic and stainless steel brackets. The residual TEGDMA and Bis-GMA monomer concentrations were determined by high performance liquid chromatographic (HPLC) analysis of the extracts after specimen immersion in ethanol/water solution for 15 days at 37 +/- 1 degree C. According to the results the highest monomer concentrations eluted were obtained from the chemically cured adhesive. Direct (through the bracket) irradiation of stainless steel brackets bonded to the visible light-cured adhesive showed high monomer elution as well. A polycarbonate base ceramic bracket manifested significantly greater amount of monomer release compared with ceramic brackets when combined with the visible light-cured adhesive. Indirect (from the incisal and cervical edges of the bracket) irradiation of the visible light-cured adhesive bonded to the stainless steel brackets resulted in lower residual monomer elution compared to that of directly (through the bracket) irradiated metallic brackets. No statistical difference was found between direct or indirect irradiation of the ceramic brackets tested, with respect to monomer elution from the light-cured adhesive.

  12. Curing kinetics of visible light curing dental resin composites investigated by dielectric analysis (DEA).

    PubMed

    Steinhaus, Johannes; Hausnerova, Berenika; Haenel, Thomas; Großgarten, Mandy; Möginger, Bernhard

    2014-03-01

    During the curing process of light curing dental composites the mobility of molecules and molecule segments is reduced leading to a significant increase of the viscosity as well as the ion viscosity. Thus, the kinetics of the curing behavior of 6 different composites was derived from dielectric analysis (DEA) using especially redesigned flat sensors with interdigit comb electrodes allowing for irradiation at the top side and measuring the ion viscosity at the bottom side. As the ion viscosities of dental composites change 1-3 orders of magnitude during the curing process, DEA provides a sensitive approach to evaluate their curing behavior, especially in the phase of undisturbed chain growth. In order to determine quantitative kinetic parameters a kinetic model is presented and examined for the evaluation of the ion viscosity curves. From the obtained results it is seen that DEA might be employed in the investigation of the primary curing process, the quality assurance of ingredients as well as the control of processing stability of the light curing dental composites.

  13. About the cure kinetics in natural rubber/styrene Butadiene rubber blends at 433 K

    NASA Astrophysics Data System (ADS)

    Mansilla, M. A.; Marzocca, A. J.

    2012-08-01

    Vulcanized blends of elastomers are employed in several goods mainly to improve physical properties and reduce costs. One of the most used blends of this kind is that composed by natural rubber (NR) and styrene butadiene rubber (SBR). The cure kinetic of these blends depends mainly on the compound formulation and the cure temperature and time. The preparation method of the blends can influence the mechanical properties of the vulcanized compounds. In this work the cure kinetic at 433 K of NR/SBR blends vulcanized with the system sulfur/TBBS (N-t-butyl-2-benzothiazole sulfenamide) is analyzed in samples prepared by mechanical mixing and solution blending. The two methods produce elastomer domains of NR and SBR, which present different microstructure due to the cure level attained during vulcanization. The cure kinetics is studied by means of rheometer tests and the model proposed by Kamal and Sourour. The analysis of the cure rate is presented and is related to the structure obtained during the vulcanization process.

  14. Light-Cured Self-Etch Adhesives Undergo Hydroxyapatite-Triggered Self-Cure.

    PubMed

    Liu, Y; Bai, X; Liu, Y W; Wang, Y

    2016-03-01

    Light cure is a popular mode of curing for dental adhesives. However, it suffers from inadequate light delivery when the restoration site is less accessible, in which case a self-cure mechanism is desirable to salvage any compromised polymerization. We previously reported a novel self-cure system mediated by ethyl 4-(dimethylamino)-benzoate (4E) and hydroxyapatite (HAp). The present work aims to investigate if such self-cure phenomenon takes place in adhesives that underwent prior inadequate light cure and to elucidate if HAp released from the dental etching process is sufficient to trigger it. Model self-etch adhesives were formulated with various components, including bis[2-methacryloyloxy)ethyl]-phosphate (2MP) as acidic monomer and trimethylbenzoyl-diphenylphosphine oxide (TPO) as photoinitiator. In vitro evolution of degree of conversion (DC) of HAp-incorporated adhesives was monitored by infrared spectroscopy during light irradiation and dark storage. Selected adhesives were allowed to etch and extract HAp from enamel, light-cured in situ, and stored in the dark, after which Raman line mapping was used to obtain spatially resolved DC across the enamel-resin interface. Results showed that TPO+4E adhesives reached DC similar to TPO-only counterparts upon completion of light irradiation but underwent another round of initiation that boosted DC to ~100% regardless of HAp level or prior light exposure. When applied to enamel, TPO-only adhesives had ~80% DC in resin, which gradually descended to ~50% in enamel, whereas TPO+4E adhesives consistently scored ~80% DC across the enamel-resin interface. These observations suggest that polymerization of adhesives that underwent insufficient light cure is salvaged by the novel self-cure mechanism, and such salvaging effect can be triggered by HAp released from dental substrate during the etching process.

  15. Method of controlling a resin curing process. [for fiber reinforced composites

    NASA Technical Reports Server (NTRS)

    Webster, Charles Neal (Inventor); Scott, Robert O. (Inventor)

    1989-01-01

    The invention relates to an analytical technique for controlling the curing process of fiber-reinforced composite materials that are formed using thermosetting resins. The technique is the percent gel method and involves development of a time-to-gel equation as a function of temperature. From this equation a rate-of-gel equation is then determined, and a percent gel is calculated which is the product of rate-of-gel times time. Percent gel accounting is used to control the proper pressure application point in an autoclave cure process to achieve desired properties in a production composite part.

  16. Advanced Fast Curing Adhesives for Adverse Conditions

    DTIC Science & Technology

    2007-07-01

    set of battle damage repair adhesives include Belzona 2311 elastomer , Belzona 1221 super metal, and Belzona metal plug, which are very fast curing...resin, and dinonylphenol (10). Marine use A-788 Splash Zone epoxy- polyamide mastic from Z Spar, Los Angeles, CA was used for testing (11). The

  17. Campus Violence: Kinds, Causes, and Cures.

    ERIC Educational Resources Information Center

    Whitaker, Leighton C., Ed.; Pollard, Jeffrey W., Ed.

    This volume offers 14 papers on the types, sources, and possible cures of violence on college campuses from prominent workers in higher education. Following a preface the titles are: (1) "Conceptualizing Campus Violence: Definitions, Underlying Factors, and Effects" by Mary L. Roark; (2) "Administrative Perspectives on Disruptive…

  18. Quantitative prediction of stresses during thermoset cure

    SciTech Connect

    Adolf, D.; Chambers, B.; Burchett, S.

    1996-07-01

    Two thin-walled Al tubes were filled with epoxy which were cured isothermally; one tube was instrumented with strain gauges, and the other with thermocouples. Finite element codes were used. Predicted and measured centerline hoop strains are shown; predictions and measurements agree. This is being applied to encapsulated components.

  19. Audacious Cures for America's Ailing Schools

    ERIC Educational Resources Information Center

    Gevirtzman, Bruce

    2011-01-01

    The problems in our nation's schools, and the cures for those problems, have been mired in confusion, innuendo, and deception. It is time someone separated the truths about our schools from the lies. Now retired from education, and finally free to speak up, veteran high school teacher Bruce J. Gevirtzman reveals his shocking ideas for fixing our…

  20. Characterization of the relationship of the cure cycle chemistry to cure cycle processing properties

    NASA Technical Reports Server (NTRS)

    Kranbuehl, D. E.

    1985-01-01

    Dynamic dielectric analysis (DDA) is used to study curing polymer systems and thermoplastics. Measurements are made over a frequency range of six decades. This wide range of frequencies increases the amount of information which can be obtained. The data is analyzed in terms of the frequency dependence of the complex permittivity epsilon sup *, specific conductivity sigma (ohm/cm) and the relaxation time tau, parameters which are characteristic of the cure state of the material and independent of the size of the sample.

  1. Bond strength of a light-cured and two auto-cured glass ionomer liners.

    PubMed

    Holtan, J R; Nystrom, G P; Olin, P S; Rudney, J; Douglas, W H

    1990-10-01

    Ninety-nine extracted human molar teeth were used in this study comparing the shear bond strengths on dentine of one light-cured and two auto-cured polyalkenoate (glass ionomer) cements. Bond strength can be influenced by differences in tooth structure. A balanced-incomplete block design (Hull and Nie, 1981) was used to reduce variation attributable to such differences. Cements were applied to paired dentine surfaces in combinations such that 66 tooth sides were treated with each material. A light-cured dentinal adhesive and composite resin restorative material were then placed and shear bond strength testing was conducted exactly 24 h after the completion of each specimen. Mean forces (MPa) for the three materials were compared using an appropriate analysis of variance model (balanced-incomplete-blocks) The shear bond strengths (MPa) of the light-cured liner (Espe, Seefeld/Oberbay, FRG) was 4.71 +/- 1.16. Vitrabond showed the greatest variance of all three materials tested, however this material's average bond strength was greater than the maximum achieved for the other materials. Student-Newman-Keuls comparison of means showed that all cements differed significantly from each other (alpha = 0.05). It is concluded that the light-cured glass ionomer liner exhibited significantly better shear bond strength performance than the two auto-cured glass ionomers tested.

  2. Cationic cure kinetics of a polyoxometalate loaded epoxy nanocomposite

    SciTech Connect

    Anderson, Benjamin J.

    2012-08-06

    The reaction cure kinetics of a novel polyoxometalate (POM) loaded epoxy nanocomposite is described. The POM is dispersed in the epoxy resin up to volume fractions of 0.1. Differential scanning calorimetry measurements show the cure of the epoxy resin to be sensitive to the POM loading. A kinetics study of the cure exotherm confirms that POM acts as a catalyst promoting cationic homopolymerization of the epoxy resin. The cure reaction is shown to propagate through two cure regimes. A fast cure at short time is shown to be propagation by the activated chain end (ACE) mechanism. A slow cure at long time is shown to be propagation by the activated monomer (AM) mechanism. The activation energies for the fast and slow cure regimes agree well with other epoxy based systems that have been confirmed to propagate by the ACE and AM mechanisms.

  3. A Study of Upgraded Phenolic Curing for RSRM Nozzle Rings

    NASA Technical Reports Server (NTRS)

    Smartt, Ziba

    2000-01-01

    A thermochemical cure model for predicting temperature and degree of cure profiles in curing phenolic parts was developed, validated and refined over several years. The model supports optimization of cure cycles and allows input of properties based upon the types of material and the process by which these materials are used to make nozzle components. The model has been refined to use sophisticated computer graphics to demonstrate the changes in temperature and degree of cure during the curing process. The effort discussed in the paper will be the conversion from an outdated solid modeling input program and SINDA analysis code to an integrated solid modeling and analysis package (I-DEAS solid model and TMG). Also discussed will be the incorporation of updated material properties obtained during full scale curing tests into the cure models and the results for all the Reusable Solid Rocket Motor (RSRM) nozzle rings.

  4. Silicone rubber curing by high intensity infrared radiation

    SciTech Connect

    Huang, T.; Tsai, J.; Cherng, C.; Chen, J.

    1994-08-10

    A high-intensity (12 kW) and compact (80 cm) infrared heating oven for fast curing (12 seconds) of tube-like silicone rubber curing studies is reported. Quality inspection by DSC and DMA and results from pilot-scale curing oven all suggest that infrared heating provides a better way of vulcanization regarding to curing time, quality, cost, and spacing over conventional hot air heating. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  5. Silicone rubber curing by high intensity infrared radiation

    NASA Astrophysics Data System (ADS)

    Huang, Tung-Way; Tsai, Jen-Hui; Cherng, Chung-Pin; Chen, Jan-Ku

    1994-08-01

    A high-intensity (12 kW) and compact (80 cm) infrared heating oven for fast curing (12 seconds) of tube-like silicone rubber curing studies is reported. Quality inspection by DSC and DMA and results from pilot-scale curing oven all suggest that infrared heating provides a better way of vulcanization regarding to curing time, quality, cost, and spacing over conventional hot air heating.

  6. Electron Beam Curing of Polymer Matrix Composites - CRADA Final Report

    SciTech Connect

    Janke, C. J.; Howell, Dave; Norris, Robert E.

    1997-05-01

    The major cost driver in manufacturing polymer matrix composite (PMC) parts and structures, and one of the elements having the greatest effect on their quality and performance, is the standard thermal cure process. Thermal curing of PMCs requires long cure times and high energy consumption, creates residual thermal stresses in the part, produces volatile toxic by-products, and requires expensive tooling that is tolerant of the high cure temperatures.

  7. 7 CFR 29.6002 - Air-cured.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... INSPECTION Standards Definitions § 29.6002 Air-cured. Tobacco cured under natural atmospheric conditions. Artificial heat sometimes is used to control excess humidity during the curing period to prevent pole-sweat... resulting from the application of artificial heat....

  8. 7 CFR 30.12 - Fire-cure.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Fire-cure. 30.12 Section 30.12 Agriculture Regulations... AND STANDARDS Classification of Leaf Tobacco Covering Classes, Types and Groups of Grades § 30.12 Fire-cure. To cure tobacco under artificial atmospheric conditions by the use of open fires, the smoke...

  9. 7 CFR 30.12 - Fire-cure.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false Fire-cure. 30.12 Section 30.12 Agriculture Regulations... AND STANDARDS Classification of Leaf Tobacco Covering Classes, Types and Groups of Grades § 30.12 Fire-cure. To cure tobacco under artificial atmospheric conditions by the use of open fires, the smoke...

  10. 7 CFR 30.12 - Fire-cure.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false Fire-cure. 30.12 Section 30.12 Agriculture Regulations... AND STANDARDS Classification of Leaf Tobacco Covering Classes, Types and Groups of Grades § 30.12 Fire-cure. To cure tobacco under artificial atmospheric conditions by the use of open fires, the smoke...

  11. 7 CFR 30.12 - Fire-cure.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Fire-cure. 30.12 Section 30.12 Agriculture Regulations... AND STANDARDS Classification of Leaf Tobacco Covering Classes, Types and Groups of Grades § 30.12 Fire-cure. To cure tobacco under artificial atmospheric conditions by the use of open fires, the smoke...

  12. 7 CFR 30.12 - Fire-cure.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false Fire-cure. 30.12 Section 30.12 Agriculture Regulations... AND STANDARDS Classification of Leaf Tobacco Covering Classes, Types and Groups of Grades § 30.12 Fire-cure. To cure tobacco under artificial atmospheric conditions by the use of open fires, the smoke...

  13. 7 CFR 29.3502 - Air-cured.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... INSPECTION Standards Official Standard Grades for Dark Air-Cured Tobacco (u.s. Types 35, 36, 37 and Foreign Type 95) § 29.3502 Air-cured. Tobacco cured under natural atmospheric conditions without the use of fire, except for the purpose of preventing pole-burn in damp weather....

  14. Improved cure method for single component silicone rubber

    NASA Technical Reports Server (NTRS)

    Lippitt, M. W.

    1969-01-01

    Water is incorporated in a carrier and then thoroughly mixed with the single component silicone rubber containing acetic anhydride as a curing agent. Because curing occurs with the water supplied internally, controlled curing is possible within a reasonable period of time, regardless of the thickness of the material.

  15. UV curing with water based materials

    SciTech Connect

    Beck, E.; Haeussling, L.; Jaeger, U.

    1995-12-01

    Conventional coatings technology requires a large effort to reduce emissions of organic solvents and other volatile organic components. Alleviations, yet not a solution to this problem are high solids coatings formulations or even powder coatings technology. An entirely different concept is used in radiation curing of coatings, where all the elements of the originally low molar mass components of the coating formulation are polymerized into one large network. Thus there should be no emissions of low molar mass compounds from UV- or Electron beam cured films. Water as a diluent in UV-curable formulations can either be used directly as a solvent or in emulsions (with the help of emulsifying agents) without a loss in performance of coatings properties, such as hardness, elasticity and reactivity. To the contrary, the prearrangement of functionalities in the final coating due to the prior phase separation in the emulsion seems to slightly increase hardness and adhesion as well as elasticity.

  16. Hematopoietic stem cell transplantation for HIV cure

    PubMed Central

    Kuritzkes, Daniel R.

    2016-01-01

    The apparent cure of an HIV-infected person following hematopoietic stem cell transplantation (HSCT) from an allogeneic donor homozygous for the ccr5Δ32 mutation has stimulated the search for strategies to eradicate HIV or to induce long-term remission without requiring ongoing antiretroviral therapy. A variety of approaches, including allogeneic HSCT from CCR5-deficient donors and autologous transplantation of genetically modified hematopoietic stem cells, are currently under investigation. This Review covers the experience with HSCT in HIV infection to date and provides a survey of ongoing work in the field. The challenges of developing HSCT for HIV cure in the context of safe, effective, and convenient once-daily antiretroviral therapy are also discussed. PMID:26731468

  17. Vacuum deposition and curing of liquid monomers

    DOEpatents

    Affinito, John D.

    1993-01-01

    The present invention is the formation of solid polymer layers under vacuum. More specifically, the present invention is the use of "standard" polymer layer-making equipment that is generally used in an atmospheric environment in a vacuum, and degassing the monomer material prior to injection into the vacuum. Additional layers of polymer or metal may be vacuum deposited onto solid polymer layers. Formation of polymer layers under a vacuum improves material and surface characteristics, and subsequent quality of bonding to additional layers. Further advantages include use of less to no photoinitiator for curing, faster curing, fewer impurities in the polymer electrolyte, as well as improvement in material properties including no trapped gas resulting in greater density, and reduced monomer wetting angle that facilitates spreading of the monomer and provides a smoother finished surface.

  18. Vacuum deposition and curing of liquid monomers

    DOEpatents

    Affinito, John D.

    1995-01-01

    The present invention is the formation of solid polymer layers under vacuum. More specifically, the present invention is the use of "standard" polymer layer-making equipment that is generally used in an atmospheric environment in a vacuum, and degassing the monomer material prior to injection into the vacuum. Additional layers of polymer or metal or oxide may be vacuum deposited onto solid polymer layers. Formation of polymer layers under a vacuum improves material and surface characteristics, and subsequent quality of bonding to additional layers. Further advantages include use of less to no photoinitiator for curing, faster curing, fewer impurities in the polymer electrolyte, as well as improvement in material properties including no trapped gas resulting in greater density, and reduced monomer wetting angle that facilitates spreading of the monomer and provides a smoother finished surface.

  19. Vacuum deposition and curing of liquid monomers

    DOEpatents

    Affinito, J.D.

    1993-11-09

    The present invention is the formation of solid polymer layers under vacuum. More specifically, the present invention is the use of standard polymer layer-making equipment that is generally used in an atmospheric environment in a vacuum, and degassing the monomer material prior to injection into the vacuum. Additional layers of polymer or metal may be vacuum deposited onto solid polymer layers. Formation of polymer layers under a vacuum improves material and surface characteristics, and subsequent quality of bonding to additional layers. Further advantages include use of less to no photoinitiator for curing, faster curing, fewer impurities in the polymer electrolyte, as well as improvement in material properties including no trapped gas resulting in greater density, and reduced monomer wetting angle that facilitates spreading of the monomer and provides a smoother finished surface.

  20. Vacuum deposition and curing of liquid monomers

    DOEpatents

    Affinito, J.D.

    1995-03-07

    The present invention is the formation of solid polymer layers under vacuum. More specifically, the present invention is the use of ``standard`` polymer layer-making equipment that is generally used in an atmospheric environment in a vacuum, and degassing the monomer material prior to injection into the vacuum. Additional layers of polymer or metal or oxide may be vacuum deposited onto solid polymer layers. Formation of polymer layers under a vacuum improves material and surface characteristics, and subsequent quality of bonding to additional layers. Further advantages include use of less to no photoinitiator for curing, faster curing, fewer impurities in the polymer electrolyte, as well as improvement in material properties including no trapped gas resulting in greater density, and reduced monomer wetting angle that facilitates spreading of the monomer and provides a smoother finished surface.

  1. Light-Curing Adhesive Repair Tapes

    NASA Technical Reports Server (NTRS)

    Allred, Ronald; Haight, Andrea Hoyt

    2009-01-01

    Adhesive tapes, the adhesive resins of which can be cured (and thereby rigidized) by exposure to ultraviolet and/or visible light, are being developed as repair patch materials. The tapes, including their resin components, consist entirely of solid, low-outgassing, nonhazardous or minimally hazardous materials. They can be used in air or in vacuum and can be cured rapidly, even at temperatures as low as -20 C. Although these tapes were originally intended for use in repairing structures in outer space, they can also be used on Earth for quickly repairing a wide variety of structures. They can be expected to be especially useful in situations in which it is necessary to rigidize tapes after wrapping them around or pressing them onto the parts to be repaired.

  2. Aloe vera as cure for lichen planus.

    PubMed

    Patil, Bharati A; Bhaskar, Hebbar Pragati; Pol, Jyoti S; Sodhi, Amandeep; Madhu, Asha V

    2013-01-01

    Oral lichen planus is a difficult condition to treat because of its chronic nature. Various treatment modalities have resulted in partial regression of symptoms but not a complete cure. Aloe vera, a product with minimal adverse effects, can be tried to treat this disorder. A 38-year-old male patient diagnosed with lichen planus of the skin and the oral mucosa was suffering from severe pain and a burning sensation intraorally and pruritus of the skin lesions. Considering the extensive involvement, an herbal alternative was considered. The patient was prescribed aloe vera juice and gel application for two months. At the nine-month follow-up, the patient was symptom-free and totally cured of the intraoral and skin lesions.

  3. An in vitro comparative SEM study of marginal adaptation of IRM, light- and chemically-cured glass ionomer, and amalgam in furcation perforations.

    PubMed

    Rajablou, N; Azimi, S

    2001-12-01

    The furcation regions of 30 human mandibular molars were perforated and sealed using four different materials: IRM, light- and chemically-cured glass ionomer cement (GIC), and amalgam. The materials were compared for marginal gaps in coronal, mid, and apical regions after routine SEM processing. While light-cured GIC showed the smallest gaps in the three regions, in mid and coronal regions chemically-cured GIC, and in apical regions amalgam, showed the largest gaps. IRM cases showed the highest rate of fillings with a good "fit", whereas the majority of amalgam cases and none of the chemically-cured GIC cases were overfilled.

  4. Sage Gene Expression Profiles Characterizing Cure

    DTIC Science & Technology

    2005-10-01

    early stage tumours (the cacoethesis of Celsus). Twentieth century progress in antisepsis , anaesthesia, and surgery changed this point of view. The first... antisepsis or anaesthesia. Nitrous oxide was described in 1842 and ether was first demonstrated in 1846. Schleiden (1838), a German, was among the first to...and antisepsis which allowed surgeons to attempt a radical cure of breast cancer. He describes a series of 616 cases, 70% of whom had skin infiltration

  5. Coating and curing apparatus and methods

    DOEpatents

    Brophy, Brenor L.; Gonsalves, Peter R.; Maghsoodi, Sina; Colson, Thomas E.; Yang, Yu S.; Abrams, Ze'ev R.

    2016-04-19

    Disclosed is a coating apparatus including flow coating and roll-coating that may be used for uniform sol-gel coating of substrates such as glass, solar panels, windows or part of an electronic display. Also disclosed are methods for substrate preparation, flow coating and roll coating. Lastly, systems and methods for curing sol-gel coatings deposited onto the surface of glass substrates using high temperature air-knives, infrared emitters and direct heat applicators are disclosed.

  6. Improved Cure-in-Place Silicone Adhesives

    NASA Technical Reports Server (NTRS)

    Blevins, C. E.; Sweet, J.; Gonzalez, R.

    1982-01-01

    Two improved cure-in-place silicone-elastomer-based adhesives have low thermal expansion and low thermal conductivity. Adhesives are flexible at low temperature and withstand high temperatures without disintegrating. New ablative compounds were initially developed for in-flight repair of insulating tile on Space Shuttle orbiter. Could find use in other applications requiring high-performance adhesives, such as sealants for solar collectors.

  7. Photothermal Monitoring Of Curing Of Polymers

    NASA Technical Reports Server (NTRS)

    Rooney, Michael

    1993-01-01

    Time-resolved infrared radiometry (TRIR) adapted to monitoring curing of some polymers in production. Proposal part of continuing effort to perfect production of hydroxy-terminated polybutadiene for use in liners of solid-fuel rocket motors. Applicable to monitoring changing states of many other materials in process. TRIR, non-contact technique implemented with remotely situated equipment and better suited to use in production.

  8. Characterization and Cure Monitoring of Structural Adhesives

    DTIC Science & Technology

    1989-02-01

    OX tiLE (OP? MTL TR 89-15 AD CHARACTERIZATION AND CURE MONITORING OF STRUCTURAL ADHESIVES CD WALTER X. ZUKAS, HOWARD H. WONG, DAVID A. DUNN, and...REPORT NUMB3ER 7. AUTHOR(s) 8. CONTRACT OR GRANT NUMBERs) Walter X. Zukas, Howard H. Wong, David A. Dunn, and Stanley E. Wentworth I. PERFORING...Technology, Gaithersburg, MD 20899 1 ATTN: B. Fanconi, Polymer Standards Division 1 D. Hunston, Polymer Standards Division 1 Dr. Stanley M. Barkin , Staff

  9. Coating and curing apparatus and methods

    DOEpatents

    Brophy, Brenor L; Maghsoodi, Sina; Neyman, Patrick J; Gonsalves, Peter R; Hirsch, Jeffrey G; Yang, Yu S

    2015-02-24

    Disclosed are coating apparatus including flow coating and roll-coating that may be used for uniform sol-gel coating of substrates such as glass, solar panels, windows or part of an electronic display. Also disclosed are methods for substrate preparation, flow coating and roll coating. Lastly systems and methods for skin curing sol-gel coatings deposited onto the surface of glass substrates using a high temperature air-knife are disclosed.

  10. Curing efficiency of various resin-based materials polymerized through different ceramic thicknesses and curing time

    PubMed Central

    Lee, Jung-Won; Cha, Hyun-Suk

    2011-01-01

    PURPOSE The aim of this in vitro study was to examine the curing efficiency of various resin-based materials polymerized through ceramic restorations with 3 different thicknesses. Curing efficiency was evaluated by determining the surface microhardness (VHN) of the resin specimens. MATERIALS AND METHODS Four kinds of resin materials were used. Z350 (3M ESPE Filtek™ Z350: A2 Shade), Z250 (3M ESPE Filtek™ Z250: A2 Shade) and Variolink® II (VL: Ivoclar vivadent, base: transparent) either with or without a self-curing catalyst (VLC: Ivoclar vivadent, catalyst: low viscosity/transparent) were filled into the silicone mold (10 mm diameter, 1 mm thick). They were cured through ceramic discs (IPS e.max Press MO-0 ingot ivoclar vivadent, 10 mm diameter, 0.5, 1 and 2 mm thicknesses) by LED light-curing units for 20 and 40 seconds. Vicker's microhardness numbers (VHNs) were measured on the bottom surfaces by a microhardness tester. Data were analyzed using a 3- way analysis of variance (ANOVA) at a significance level of 0.05. RESULTS The thickness of ceramic disc increased, the VHNs of all four resin types were decreased (P<.05). The mean VHN values of the resins light cured for 40 seconds were significantly higher than that of LED for 20 seconds in all four resin materials (P<.05). VLC showed significantly higher VHN values than VL regardless of other conditions (P<.05). Z350 and Z250 showed higher values than VL or VLC (P<.01). CONCLUSION Thinner ceramic disc with increased curing time resulted higher VHN values of all resin materials. The use of a catalyst produced a greater hardness with all polymerization methods. Restorative resin materials (Z350, Z250) showed higher VHN values than resin cement materials (VL, VLC). PMID:22053242

  11. Mechanism and kinetics of the curing process in a resin system

    NASA Technical Reports Server (NTRS)

    Moacanin, J.; Cizmecioglu, M.; Hong, S. D.; Gupta, A.

    1983-01-01

    The present investigation is concerned with the development of a cure reactivity model for a resin system consisting of tetraglycidyl diaminodiphenyl methane (TGDDM) and diaminodiphenyl sulfone (DDS), taking into account the temperature range from 153 to 177 C. Differential scanning calorimetry and FT-IR spectroscopy have been used to investigate the cure kinetics of the resin with the objective to obtain a correlation between the total conversion and the rates of formation and disappearance of specific functionalities. It was found that the overall process can be satisfactorily described in terms of two first order processes.

  12. Lethal acute demyelinization with encephalo-myelitis as a complication of cured Cushing's disease.

    PubMed

    Chevalier, N; Hieronimus, S; Vandenbos, F; Delmont, E; Cua, E; Cherick, F; Paquis, P; Michiels, J-F; Fenichel, P; Brucker-Davis, F

    2010-12-01

    Cushing's disease is usually associated with higher mortality rate, especially from cardiovascular causes. Development or exacerbation of autoimmune or inflammatory diseases is known to occur in patients with hypercortisolism after cure. We report for the first time a 34-year old woman with a psychiatric background, who developed four months after the surgical cure of Cushing's disease an acute disseminated encephalomyelitis (ADEM) presenting initially as a psychiatric illness. We hypothesize that the recent correction of hypercortisolism triggered ADEM and that the atypical presentation, responsible for diagnosis delay, led to the death of this patient.

  13. Characterization of the relationship of the cure cycle chemistry to cure cycle processing properties

    NASA Technical Reports Server (NTRS)

    Kranbuehl, D. E.

    1986-01-01

    Dynamic Dielectric measurements made over a wide range of frequency provide a sensitive and convenient means for monitoring the cure process in thermosets and thermoplastics. The measurement of dielectric relaxation is one of only a few instrumental techniques available for studying molecular properties in both the liquid and solid states. Furthermore, it is probably the only convenient experimental technique for studying the polymerization process of going from a monomeric liquid of varying viscosity to a crosslinked, insoluble, high temperature solid. The objective of the research is to develop on-line dielectric instrumentation for quantitative nondestructive material evaluation and closed loop smart cure cycle control. The key is to relate the chemistry of the cure cycle process to the dielectric properties of the polymer system by correlating the time, temperature, and frequency dependent dielectric measurements with chemical characterization measurements. Measurement of the wide variation in magnitude of the complex permittivity with both frequency and state of cure, coupled with chemical characterization work, have been shown in the laboratory to have the potential to determine: resin quality, composition and age; cure cycle window boundaries; onset of flow and point of maximum flow; extent of and completion of reaction; evolution of volatiles; T sub g; and, crosslinking and molecular weight buildup.

  14. Microhardness and Young's modulus of a bonding resin cured with different curing units.

    PubMed

    Yamauti, Monica; Nikaido, Toru; Ikeda, Masaomi; Otsuki, Masayuki; Tagami, Junji

    2004-12-01

    This study evaluated the microhardness and Young's modulus of a photocurable bonding resin, Clearfil SE Bond (SE), cured with four curing units at different distances. The curing units used were: Candelux (Quartz-tungsten halogen), Lux-O-Max (Blue light emitting diode), Arc-light (Plasma-arc), and Rayblaze (Metal halide). Discs of bonding resin were prepared using vinyl molds and were photocured at the top surface with light tip at three different distances (contact, 2 and 4 mm). After 24 hours of storage in water at 37 degrees C, the specimens were sectioned into halves, embedded in epoxy resin, and polished. The microhardness and Young's modulus of this bonding resin were measured using a nanoindentation tester. Six specimens were prepared for each group. The data was statistically analyzed using two-way ANOVA test and Tukey multiple comparison test (p < 0.01). The microhardness of SE was affected by light source and distance, as was Young's modulus. Candelux and Rayblaze presented the highest hardness and Young's modulus results. Both properties presented high values when the curing unit tip was maintained in contact with the irradiated surface. Increasing the distance between the curing unit tip and the irradiated surface decreased the hardness and Young's modulus of SE.

  15. Two-year color changes of light-cured composites: influence of different light-curing units.

    PubMed

    Usumez, Aslihan; Ozturk, Nilgun; Ozturk, Bora

    2005-01-01

    This study determined color changes in a composite cured with various types of curing units after two years. A hybrid (Clearfil AP-X) composite was cured with a conventional halogen, a high intensity halogen, a plasma arc and a light emitting diode unit. The specimens were stored in light-proof boxes after the curing procedure to avoid further exposure to light and stored in 37 degrees C in 100% humidity. Colorimetric values of the specimens immediately after curing and after two years were measured using a colorimeter. The CIE 1976 L*a*b color system was used to determine color differences. Differences from baseline were calculated as deltaE*ab. Data were analyzed with two-way analysis of variance (p<0.05). The deltaE*ab values varied significantly, depending on the curing unit used. The specimens cured with a plasma arc curing unit induced significantly higher color changes than any other specimen and the color differences were also visually appreciable by the non-skilled operator (deltaE*ab >2.5). The specimens cured with a high intensity halogen curing unit produced the lowest color change; however, there were no statistically significant differences among the color changes of specimens cured with conventional halogen, high intensity halogen and the light emitting diode unit, and the color changes were not clinically relevant (deltaE*ab <2.5). The results of this study suggest that composite materials undergo measurable changes due to curing unit exposure. The specimens cured with a plasma arc light showed the highest color changes as compared to specimens cured with other curing units.

  16. Cure shrinkage effects in epoxy and polycyanate matrix composites

    SciTech Connect

    Spellman, G.P.

    1995-12-22

    A relatively new advanced composite matrix, polycyanate ester, was evaluated for cure shrinkage. The chemical cure shrinkage of composites is difficult to model but a number of clever experimental techniques are available to the investigator. In this work the method of curing a prepreg layup on top of a previously cured laminate of identical ply composition is utilized. The polymeric matrices used in advanced composites have been primarily epoxies and therefore a common system of this type, Fiberite 3501-6, was used as a base case material. Three polycyanate matrix systems were selected for the study. These are: Fiberite 954-2A, YLA RS-3, and Bryte Technology BTCy-1. The first three of these systems were unidirectional prepreg with carbon fiber reinforcement. The Bryte Technology material was reinforced with E-glass fabric. The technique used to evaluate cure shrinkage results in distortion of the flatness of an otherwise symmetric laminate. The first laminate is cured in a conventional fashion. An identical layup is cured on this first laminate. During the second cure all constituents are exposed to the same thermal cycles. However, only the new portion of the laminate will experience volumetric changes associate with matrix cure. The additional strain of cure shrinkage results in an unsymmetric distribution of residual stresses and an associated warpage of the laminate. The baseline material, Fiberite 3501-6, exhibited cure shrinkage that was in accordance with expectations. Cure strains were {minus}4.5E-04. The YLA RS-3 material had cure strains somewhat lower at {minus}3.2E-04. The Fiberite 954-2A cure strain was {minus}1.5E-04 that is 70% lower than the baseline material. The glass fabric material with the Bryte BTCy-1 matrix did not result in meaningful results because the processing methods were not fully compatible with the material.

  17. Curing and Post-curing Viscoelastic Monitoring of an Epoxy Resin

    NASA Astrophysics Data System (ADS)

    Ghodhbani, N.; Marechal, P.; Duflo, H.

    An experimental setup has been developed for the monitoring of ultrasonic parameters during polymerization in the context of the monitoring of composite plate production. An analytical approach is proposed based on the modeling of the wave velocity fitted by a Weibull distribution and was investigated to validate this approach by the Debye series modeling (DSM). The monitoring of the cured epoxy is also performed after curing in order to study the thermal transformation compared with DSC measurements. As a result, an approximated frequency-temperature (f, T) model is proposed for attenuation and velocity frequency and temperature dispersions.

  18. Describing Adequacy of cure with maximum hardness ratios and non-linear regression.

    PubMed

    Bouschlicher, Murray; Berning, Kristen; Qian, Fang

    2008-01-01

    Knoop Hardness (KH) ratios (HR) > or = 80% are commonly used as criteria for the adequate cure of a composite. These per-specimen HRs can be misleading, as both numerator and denominator may increase concurrently, prior to reaching an asymptotic, top-surface maximum hardness value (H(MAX)). Extended cure times were used to establish H(MAX) and descriptive statistics, and non-linear regression analysis were used to describe the relationship between exposure duration and HR and predict the time required for HR-H(MAX) = 80%. Composite samples 2.00 x 5.00 mm diameter (n = 5/grp) were cured for 10 seconds, 20 seconds, 40 seconds, 60 seconds, 90 seconds, 120 seconds, 180 seconds and 240 seconds in a 2-composite x 2-light curing unit design. A microhybrid (Point 4, P4) or microfill resin (Heliomolar, HM) composite was cured with a QTH or LED light curing unit and then stored in the dark for 24 hours prior to KH testing. Non-linear regression was calculated with: H = (H(MAX)-c)(1-e(-kt)) +c, H(MAX) = maximum hardness (a theoretical asymptotic value), c = constant (t = 0), k = rate constant and t = exposure duration describes the relationship between radiant exposure (irradiance x time) and HRs. Exposure durations for HR-H(MAX) = 80% were calculated. Two-sample t-tests for pairwise comparisons evaluated relative performance of the light curing units for similar surface x composite x exposure (10-90s). A good measure of goodness-of-fit of the non-linear regression, r2, ranged from 0.68-0.95. (mean = 0.82). Microhybrid (P4) exposure to achieve HR-H(MAX = 80% was 21 seconds for QTH and 34 seconds for the LED light curing unit. Corresponding values for microfill (HM) were 71 and 74 seconds, respectively. P4 HR-H(MAX) of LED vs QTH was statistically similar for 10 to 40 seconds, while HM HR-H(MAX) of LED was significantly lower than QTH for 10 to 40 seconds. It was concluded that redefined hardness ratios based on maximum hardness used in conjunction with non-linear regression

  19. Cure kinetics of epoxy matrix resin by differential scanning calorimetry

    NASA Technical Reports Server (NTRS)

    Cizmecioglu, M.; Gupta, A.

    1982-01-01

    A study was made on the cure kinetics of an epoxy neat-resin (Narmco 5208) using Differential Scanning Calorimetry (DSC). Two interrelated analytical methods were applied to dynamic DSC data for evaluating the kinetic parameters, such as activation energy, E, the order of reaction, n, and the total heat of polymerization (or crosslinking), delta H sub t. The first method was proposed by Ellerstein (1968), and uses a thorough differential-integral analysis of a single DSC curve to evaluate the kinetic parameters. The second method was proposed by Kissinger (1957), and uses multiple DSC curves obtained at various heating rates to evaluate E regardless of n. Kinetic analysis of Narmco 5208 epoxy resin showed that the reaction order, n, is substantially affected by the rate of heating; i.e., n is approximately 2 at slow scan rates but is reduced to 1.5 at higher scan rates. The activation energy, E, is not affected by the scan rate, and the average value of E is 25.6 + or - 1.8 kcal/mole.

  20. The development of low temperature curing adhesives

    NASA Technical Reports Server (NTRS)

    Green, H. E.; Sutherland, J. D.; Hom, J. M.; Sheppard, C. H.

    1975-01-01

    An approach for the development of a practical low temperature (293 K-311 K/68 F-100 F) curing adhesive system based on a family of amide/ester resins was studied and demonstrated. The work was conducted on resin optimization and adhesive compounding studies. An improved preparative method was demonstrated which involved the reaction of an amine-alcohol precursor, in a DMF solution with acid chloride. Experimental studies indicated that an adhesive formulation containing aluminum powder provided the best performance when used in conjunction with a commercial primer.

  1. Lower-curing-temperature PMR polyimides

    NASA Technical Reports Server (NTRS)

    Delvigs, P.

    1982-01-01

    Partial substitution of a p-aminostyrene end-cap for the monomethyl ester of 5-norbornene-2, 3-dicarboxylic acid lowered the final cure temperature of typical PMR resins from 600 F to 500 F. The weight loss characteristics of neat resins and graphite fiber composites prepared by using the mixed end-cap approach were determined at 600 F. The room temperature and short-time elevated temperature mechanical properties of the composites at 550 F and 600 F were determined. The mechanical property retention characteristics of the composites at 550 F and 600 F are discussed.

  2. The cure for employee malaise--motivation.

    PubMed

    Dawson, K M; Dawson, S N

    1991-01-01

    Although working conditions, hours, pay, and advancement opportunities are better now than in the 1950s--the "golden age" of American business--today's workers are significantly less satisfied. Why? The authors believe the cause of this malaise is lack of motivation. This article examines several techniques to cure employee malaise and discusses the long-term benefits of these techniques, which include empowerment, recognition, career development, the Pygmalion effect, incentives, and rewards. By making a commitment to these motivational techniques, managers will boost the morale and enthusiasm of their employees and their organization. This motivational process is not quick and easy; developing your employees is an ongoing process.

  3. Reaction cured glass and glass coatings

    NASA Technical Reports Server (NTRS)

    Goldstein, H. E.; Leiser, D. B.; Katvala, V. W. (Inventor)

    1978-01-01

    The invention relates to reaction cured glass and glass coatings prepared by reacting a compound selected from the group consisting of silicon tetraboride, silicon hexaboride, other boron silicides, boron and mixtures with a reactive glass frit composed of a porous high silica borosilicate glass and boron oxide. The glassy composites of the present invention are useful as coatings on low density fibrous porous silica insulations used as heat shields and for articles such as reaction vessels that are subjected to high temperatures with rapid heating and cooling and that require resistance to temperature and repeated thermal shock at temperatures up to about 1482C (2700PF).

  4. Epoxy resin cure. [Phenyl glycidyl ether

    SciTech Connect

    Smith, R.E.; Woodburn, G.L.

    1986-07-01

    The reactions that occur between the model epoxy, phenyl glycidyl ether, and the cure agent dicyandiamide (DICY) have been investigated using nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR), gel permeation chromatography (GPC), and high-performance liquid chromatography (HPLC) techniques. It is shown that the reaction at 130/sup 0/C requires 90 min for completion when catalyzed by boron trifluoride monoethyl amine (BF/sub 3/-MEA). At least three major products are formed. The identity of these products is based on previously published spectroscopic data. 3 refs., 5 figs.

  5. UV-curing of natural rubber based coatings

    SciTech Connect

    Decker, C.; Le Xuan, H.; Nguyen, T.V.T.

    1995-12-01

    The crosslinking polymerization of acrylate- or epoxy-functionalized natural rubber was shown to proceed rapidly upon UV exposure in the presence of radical- or cationic-type photoinitiators. The polymerization process was studied quantitatively by infrared spectroscopy, and found to develop with long kinetic chains. The addition of an acrylate monomer increased markedly the reaction rate and the final degree of conversion, because of its plasticizing effect in these solid films. Interpenetrating polymer networks were formed by a single 1 s exposure of a 1/1 blend of a diacrylate monomer and an epoxidized natural rubber, in the presence of both radical and cationic photoinitiators. The UV-curing of an epoxidized and acrylated natural rubber leads to the formation of a dual polymer network which combines both toughness and flexibility and gives impact resistant coatings having a good resistance to scratching and abrasion.

  6. A Review of Black Salve: Cancer Specificity, Cure, and Cosmesis

    PubMed Central

    King, Graham J.; Pyne, John H.; Anoopkumar-Dukie, Shailendra

    2017-01-01

    Black salve is a topical escharotic used for the treatment of skin cancer. Although promoted as a safe and effective alternative to conventional management by its proponents, limited clinical research has been undertaken to assess its efficacy and potential toxicities. Patients are increasingly utilizing the Internet as a source of health information. As a minimally regulated space, the quality and accuracy of this information vary considerably. This review explores four health claims made by black salve vendors, investigating its natural therapy credentials, tumour specificity, and equivalence to orthodox medicine in relation to skin cancer cure rates and cosmesis. Based upon an analysis of in vitro constituent cytotoxicity, in vivo post black salve histology, and experience with Mohs paste, black salve is likely to possess normal tissue toxicity with some cancer cell lines being relatively resistant to its effects. This may explain the incongruous case study reports of excessive scarring, deformity, and treatment failure. PMID:28246541

  7. Critical parameters for electron beam curing of cationic epoxies and property comparison of electron beam cured cationic epoxies versus thermal cured resins and composites

    SciTech Connect

    Janke, C.J.; Norris, R.E.; Yarborough, K.; Havens, S.J.; Lopata, V.J.

    1997-01-16

    Electron beam curing of composites is a nonthermal, nonautoclave curing process offering the following advantages compared to conventional thermal curing: substantially reduced manufacturing costs and curing times; improvements in part quality and performance; reduced environmental and health concerns; and improvements in material handling. In 1994 a Cooperative Research and Development Agreement (CRADA), sponsored by the Department of Energy Defense Programs and 10 industrial partners, was established to advance electron beam curing of composites. The CRADA has successfully developed hundreds of new toughened and untoughened resins, offering unlimited formulation and processing flexibility. Several patent applications have been filed for this work. Composites made from these easily processable, low shrinkage material match the performance of thermal cured composites and exhibit: low void contents comparable to autoclave cured composites (less than 1%); superb low water absorption values in the same range as cyanate esters (less than 1%); glass transition temperatures rivaling those of polyimides (greater than 390 C); mechanical properties comparable to high performance, autoclave cured composites; and excellent property retention after cryogenic and thermal cycling. These materials have been used to manufacture many composite parts using various fabrication processes including hand lay-up, tow placement, filament winding, resin transfer molding and vacuum assisted resin transfer molding.

  8. Applications of dielectric analysis for cure monitoring and control in the polyester SMC/BMC molding industry

    NASA Astrophysics Data System (ADS)

    Shepard, David D.; Day, David R.; Craven, Kelly J.

    1995-03-01

    Dielectric analysis is routinely used for monitoring the cure of thermosetting resins. Implantable, disposable sensors allow measurements of the curing process to be made in various locations throughout a part. Permanent, reusable sensors flush mounted in the mold allow the measurements to be made automatically during each molding cycle. This paper discusses process development, QA/QC, and production control in the polyester SMC/BMC industry. The curing rate through the cross-section of SMC parts of thicknesses up to 3/4 of an inch is examined. The effect of aging temperature on the reactivity of BMC demonstrates the use of dielectric analysis as a QA/QC test. Finally, it is shown that overall cycle times can be reduced by real time identification of the part-to-part variability in cure times during production molding. This allows closed-loop feedback to the press controller as to the proper time to demold each part.

  9. Curing chemistry of phenylethynyl-terminated imide oligomers: Model compounds, carbon-13 labeling and cure analysis

    NASA Astrophysics Data System (ADS)

    Roberts, Christopher Chad

    1998-11-01

    Phenylethynyl-terminated imide oligomers (PETI) are currently considered the state-of-the-art high performance resins for aerospace applications. The processing of these resins is more facile because of their low molecular weight, but PETI's cure to form a tough, solvent-resistant material. However, the final cure structure was a complete mystery. Hence, the present study was set forth with three essential goals. The determination of the final structure of the crosslinked polymer is of obvious importance. Second, the crosslinking mechanism and controlling factors is also of interest. Lastly, the final structure of the crosslinked polymers was correlated with mechanical and thermal properties, thereby helping to establish the structure-processing-properties relationships for PETI resins. These goals were accomplished by using a combination of synthesis of model compounds synthesis and proposed cure products, sp{13}C labeling of the ethynyl endgroup in PETI's, monitoring of the thermal cure using solid state sp{13}C NMR and ESR and molecular modeling techniques. Phenylethynyl endcapping agents, 4-(phenylethynyl)phthalic anhydride (PEPA) and 3-(phenylethynyl)aniline (3PEA), were synthesized via the palladium-catalyzed coupling of phenylacetylene with 4-bromophthalic anhydride or 3-iodonitrobenzene followed by reduction to 3PEA, respectively. Isolated yields of 41 and 86% for 3PEA and PEPA were obtained, respectively. Model compounds were synthesized from 3PEA and PEPA by reacting with them the appropriate aniline or phthalic anhydride derivative. Model compounds included N-pentafluorophenyl-4-(phenylethynyl)phthalimide (PEPA/F5An), N-(4-trifluoromethyl-phenyl)4-(phenylethynyl)phthalimide (PEPA/F3CAn), N-lbrack 3-(phenylethynyl)phenylrbrack\\ phthalimide (3PEA/PA), N-phenyl-4-(phenylethynyl)phthalimide (PEPA/An), N-(4-phenoxyphenyl)4-(phenylethynyl)phthalimide (PEPA/POAn), and N-(1-naphthyl)-4-(phenylethynyl)phthalimide (PEPA/Anaph). Proposed cure products such as

  10. Informed consent to HIV cure research.

    PubMed

    Bromwich, Danielle; Millum, Joseph R

    2017-02-01

    Trials with highly unfavourable risk-benefit ratios for participants, like HIV cure trials, raise questions about the quality of the consent of research participants. Why, it may be asked, would a person with HIV who is doing well on antiretroviral therapy be willing to jeopardise his health by enrolling in such a trial? We distinguish three concerns: first, how information is communicated to potential participants; second, participants' motivations for enrolling in potentially high risk research with no prospect of direct benefit; and third, participants' understanding of the details of the trials in which they enrol. We argue that the communication concern is relevant to the validity of informed consent and the quality of decision making, that the motivation concern does not identify a genuine problem with either the validity of consent or the quality of decision making and that the understanding concern may not be relevant to the validity of consent but is relevant to the quality of decision making. In doing so, we derive guidance points for researchers recruiting and enrolling participants into their HIV cure trials, as well as the research ethics committees reviewing proposed studies.

  11. CURE: Clean use of reactor energy

    SciTech Connect

    1990-05-01

    This paper presents the results of a joint Westinghouse Hanford Company (Westinghouse Hanford)-Pacific Northwest Laboratory (PNL) study that considered the feasibility of treating radioactive waste before disposal to reduce the inventory of long-lived radionuclides, making the waste more suitable for geologic disposal. The treatment considered here is one in which waste would be chemically separated so that long-lived radionuclides can be treated using specific processes appropriate for the nuclide. The technical feasibility of enhancing repository performance by this type of treatment is considered in this report. A joint Westinghouse Hanford-PNL study group developed a concept called the Clean Use of Reactor Energy (CURE), and evaluated the potential of current technology to reduce the long-lived radionuclide content in waste from the nuclear power industry. The CURE process consists of three components: chemical separation of elements that have significant quantities of long-lived radioisotopes in the waste, exposure in a neutron flux to transmute the radioisotopes to stable nuclides, and packaging of radionuclides that cannot be transmuted easily for storage or geologic disposal. 76 refs., 32 figs., 24 tabs.

  12. Out-of-Autoclave Cure Composites

    NASA Technical Reports Server (NTRS)

    Hayes, Brian S.

    2015-01-01

    As the size of aerospace composite parts exceeds that of even the largest autoclaves, the development of new out-of-autoclave processes and materials is necessary to ensure quality and performance. Many out-of-autoclave prepreg systems can produce high-quality composites initially; however, due to long layup times, the resin advancement commonly causes high void content and variations in fiber volume. Applied Poleramic, Inc. (API), developed an aerospace-grade benzoxazine matrix composite prepreg material that offers more than a year out-time at ambient conditions and provides exceptionally low void content when out-of-autoclave cured. When compared with aerospace epoxy prepreg systems, API's innovation offers significant improvements in terms of out-time at ambient temperature and the corresponding tack retention. The carbon fiber composites developed with the optimized matrix technology have significantly better mechanical performance in terms of hot-wet retention and compression when compared with aerospace epoxy matrices. These composites also offer an excellent overall balance of properties. This matrix system imparts very low cure shrinkage, low coefficient of thermal expansion, and low density when compared with most aerospace epoxy prepreg materials.

  13. Adhesive Properties of Cured Phenylethynyl Containing Imides

    NASA Technical Reports Server (NTRS)

    Jensen, Brian J.; Chang, Alice C.

    1997-01-01

    Considerable attention has been directed towards acetylene terminated oligomers over the last 20 years' and recent work has focused on phenylethynyl terminated imide (PETI) oligomers. These reactive oligomers possess several features which make them attractive candidates for use as composite matrices and adhesives. The phenylethynyl group can be readily incorporated into many different functionalized oligomers. The reactive oligomers possess relatively low melt viscosities and thermally cure without the evolution of volatile by-products. Once cured, they typically display high glass transition temperatures (Tgs), excellent solvent resistance and high mechanical properties. new modified phenylethynyl-terminated imide (LaRC MPEI) oligomers were synthesized at various molecular weights utilizing a small amount of trifunctional amine. As long as the amount of triamine is relatively small, this approach produces a mixture of linear, star-shaped and branched polymer chains that has lower melt and solution viscosity than an equivalent molecular weight linear phenylethynyl terminated imide oligomers. The work reported herein involves the synthesis and characterization of a copolymer using this approach and the preparation of blends utilizing a phenylethynyl containing reactive plasticizer of lower molecular weight called LaRC LV-121. The chemistry and properties of this new MPEI as well as some blends of MPEI with LV-121, are presented and compared to the linear version, LARC-PETI-5.

  14. Rheokinetic analysis on the curing process of HTPB-DOA- MDI binder system

    NASA Astrophysics Data System (ADS)

    Chai, T.; Liu, Y. C.; Ma, H.; Yu, Y. W.; Yuan, J. M.; Wang, J. H.; Guo, J. H.

    2016-07-01

    Polymer bonded explosives (PBXs) are a kind of rubbery explosives, in which the explosive components are bound together by a polymeric binder. The hydroxyl terminated polybutadiene (HTPB)-based polyurethane binder systems possess a unique combination of properties, including superior adhesion, excellent mechanical properties and have been widely used in rocket propellants, PBXs and other weapons. The cure reaction between HTPB and diisocyanates in the castable PBXs plays an important role in the adjustment of process parameters as well as properties of explosive formulations. In this paper, viscosity measurements were carried out at different temperatures (15oC, 25oC, 35oC, 45oC, 55oC) to a series of systemic studies on the viscosity build-up and rheological reaction rate constant during the curing process of the of HTPB- dioctyl adipate (DOA)-diphenyl methane diisocyanate (MDI) binder system, discovered and explained the phenomenon that the pot-life of the binder system was prolonged when the curing temperature raised and the curing reaction rate was accelerated. And the rheology kinetic model of the HTPB-DOA-MDI binder system was established.

  15. Cure Kinetics of Epoxy Nanocomposites Affected by MWCNTs Functionalization: A Review

    PubMed Central

    Saeb, Mohammad Reza; Bakhshandeh, Ehsan; Khonakdar, Hossein Ali; Mäder, Edith; Scheffler, Christina; Heinrich, Gert

    2013-01-01

    The current paper provides an overview to emphasize the role of functionalization of multiwalled carbon nanotubes (MWCNTs) in manipulating cure kinetics of epoxy nanocomposites, which itself determines ultimate properties of the resulting compound. In this regard, the most commonly used functionalization schemes, that is, carboxylation and amidation, are thoroughly surveyed to highlight the role of functionalized nanotubes in controlling the rate of autocatalytic and vitrification kinetics. The current literature elucidates that the mechanism of curing in epoxy/MWCNTs nanocomposites remains almost unaffected by the functionalization of carbon nanotubes. On the other hand, early stage facilitation of autocatalytic reactions in the presence of MWCNTs bearing amine groups has been addressed by several researchers. When carboxylated nanotubes were used to modify MWCNTs, the rate of such reactions diminished as a consequence of heterogeneous dispersion within the epoxy matrix. At later stages of curing, however, the prolonged vitrification was seen to be dominant. Thus, the type of functional groups covalently located on the surface of MWCNTs directly affects the degree of polymer-nanotube interaction followed by enhancement of curing reaction. Our survey demonstrated that most widespread efforts ever made to represent multifarious surface-treated MWCNTs have not been directed towards preparation of epoxy nanocomposites, but they could result in property synergism. PMID:24348181

  16. In situ cure monitoring of advanced fiber reinforced composites

    NASA Astrophysics Data System (ADS)

    Powell, Graham R.; Crosby, Peter A.; Fernando, Gerard F.; France, Chris M.; Spooncer, Ronald C.; Waters, David N.

    1995-04-01

    This paper describes a comparative study of in-situ cure monitoring and cure modelling by three methods: (a) evanescent wave spectroscopy, (b) refractive index change, (c) near- infrared spectroscopy. Optical fibers were embedded into aerospace epoxy resins during the manufacturing process of the composite. The cure characteristics were then tracked in real- time during the processing of the material via evanescent wave interaction. This technique is based upon monitoring of characteristic infrared absorption bands of the resin system to find the concentration of the epoxy and amine hardener as a function of cure time. Hence this technique is suitable for on-line process monitoring and optimization. Results obtained from the optical fiber sensors were used to model the curing behavior of the resin system. The results were compared with near-infrared spectroscopy and differential scanning calorimetry experiments carried out under similar conditions. The feasibility of utilizing refractive index changes to monitor the extent of cure has also been demonstrated.

  17. Stress In A Fiber During Curing Of Surrounding Matrix Resin

    NASA Technical Reports Server (NTRS)

    Bowles, Kenneth J.; Madhukar, Madhu S.; Kosuri, Ranga P.

    1995-01-01

    Experiments run to determine variation in tensile stress in single fiber during curing of matrix resin surrounding fiber. Study part of effort to understand physical mechanisms affecting residual stresses in matrix/fiber composites, with view toward optimizing curing cycles (in particular, optimizing temperature-vs.-time schedules of final cooldowns to ambient temperature) to minimize residual stresses. Results signify primary mechanisms affecting residual stress in fibers are thermal expansion and contraction and cure shrinkage of matrix material.

  18. Cure Characteristics of Tricyanate Ester High Temperature Composite Resins (PREPRINT)

    DTIC Science & Technology

    2011-02-09

    measurements of cure kinetics were undertaken using both isothermal and non-isothermal DSC , and compared to measures of conversion obtained through IR...measurements of cure kinetics were undertaken using both isothermal and non-isothermal DSC , and compared to measures of conversion obtained through IR...the effect of impurities on cure kinetics, comparative kinetics derived from non-isothermal and isothermal differential scanning calorimetry ( DSC

  19. Process Formulations And Curing Conditions That Affect Saltstone Properties

    SciTech Connect

    Reigel, M. M.; Pickenheim, B. R.; Daniel, W. E.

    2012-09-28

    The first objective of this study was to analyze saltstone fresh properties to determine the feasibility of reducing the formulation water to premix (w/p) ratio while varying the amount of extra water and admixtures used during processing at the Saltstone Production Facility (SPF). The second part of this study was to provide information for understanding the impact of curing conditions (cure temperature, relative humidity (RH)) and processing formulation on the performance properties of cured saltstone.

  20. Optical fibre grating refractometers for resin cure monitoring

    NASA Astrophysics Data System (ADS)

    Buggy, S. J.; Chehura, E.; James, S. W.; Tatam, R. P.

    2007-06-01

    The use of fibre grating refractometers as a means of monitoring the cure of a UV-cured epoxy resin is presented. The wavelength shift of the attenuation bands of a long period grating and the spectral response of a tilted fibre Bragg grating sensor were measured simultaneously during the cure of the resin and compared with measurements made using a fibre optic Fresnel-based refractometer. The results showed a good correlation (6 × 10-3 rius) and illustrate the potential of the techniques for non-invasive composite material cure monitoring.

  1. Effect of Curing Profile on Kaolin-based Geopolymers

    NASA Astrophysics Data System (ADS)

    Heah, C. Y.; Kamarudin, H.; Bakri, A. M. Mustafa Al; Binhussain, M.; Luqman, M.; Nizar, I. Khairul; Ruzaidi, C. M.; Liew, Y. M.

    Depending on the processing conditions, geopolymers can exhibit a wide variety of properties and characteristics. Curing profile serves as a crucial parameter in synthesis of geopolymers. In this paper, the influence of curing temperature and curing time on the properties of kaolin-based geopolymer was studied. The samples were separated into several curing conditions; including curing at ambient temperature, 40 °C, 60 °C, 80 °C and 100 °C for 1 day, and up to 3 days. The compressive strength and SEM analysis of geopolymer products were evaluated. Results showed that curing condition has a significant effect on the mechanical properties of kaolin-based geopolymer. Generally, curing at ambient temperature was not feasible, while increase in temperature favored the strength development. In addition, prolonged curing time improved the geopolymerization process, and led to higher strength gain. However, curing at high temperature for a long period of time caused failure of the sample at a later age.

  2. Bending strength and depth of cure of light-cured composite resins irradiated using filters that simulate enamel.

    PubMed

    Arikawa, H; Kanie, T; Fujii, K; Shinohara, N

    2004-01-01

    This study evaluates the light-attenuating effects of enamel on the properties of light-cured restorative resins using simple experimental filters. Three filters were designed to replicate the light transmittance characteristics of 0.5, 1.0 and 1.5 mm thick human enamel. The bending strength, depth of cure, and levels of residual monomer for 12 shades of three commercial light-cured composite resins were examined. These resins were cured either using direct irradiation from a light source or irradiation through one of the filters. For all materials, the bending strength and depth of cure of specimens irradiated through a filter were lower and the levels of residual monomer were higher than those found in specimens irradiated directly. The results indicate that the light-attenuating effect of enamel reduces the polymerization efficiency, resulting in poorer mechanical properties of light-cured composite resins.

  3. Stratospheric experiments on curing of composite materials

    NASA Astrophysics Data System (ADS)

    Chudinov, Viacheslav; Kondyurin, Alexey; Svistkov, Alexander L.; Efremov, Denis; Demin, Anton; Terpugov, Viktor; Rusakov, Sergey

    2016-07-01

    Future space exploration requires a large light-weight structure for habitats, greenhouses, space bases, space factories and other constructions. A new approach enabling large-size constructions in space relies on the use of the technology of polymerization of fiber-filled composites with a curable polymer matrix applied in the free space environment on Erath orbit. In orbit, the material is exposed to high vacuum, dramatic temperature changes, plasma of free space due to cosmic rays, sun irradiation and atomic oxygen (in low Earth orbit), micrometeorite fluence, electric charging and microgravitation. The development of appropriate polymer matrix composites requires an understanding of the chemical processes of polymer matrix curing under the specific free space conditions to be encountered. The goal of the stratospheric flight experiment is an investigation of the effect of the stratospheric conditions on the uncured polymer matrix of the composite material. The unique combination of low residual pressure, high intensity UV radiation including short-wave UV component, cosmic rays and other aspects associated with solar irradiation strongly influences the chemical processes in polymeric materials. We have done the stratospheric flight experiments with uncured composites (prepreg). A balloon with payload equipped with heater, temperature/pressure/irradiation sensors, microprocessor, carrying the samples of uncured prepreg has been launched to stratosphere of 25-30 km altitude. After the flight, the samples have been tested with FTIR, gel-fraction, tensile test and DMA. The effect of cosmic radiation has been observed. The composite was successfully cured during the stratospheric flight. The study was supported by RFBR grants 12-08-00970 and 14-08-96011.

  4. Curing of epoxy matrix composite in stratosphere

    NASA Astrophysics Data System (ADS)

    Kondyurin, Alexey; Kondyurina, Irina; Bilek, Marcela

    Large structures for habitats, greenhouses, space bases, space factories are needed for next stage of space exploitation. A new approach enabling large-size constructions in space relies on the use of the polymerization technology of fiber-filled composites with a curable polymer matrix applied in the free space environment. The polymerisation process is proposed for the material exposed to high vacuum, dramatic temperature changes, space plasma, sun irradiation and atomic oxygen (in low Earth orbit), micrometeorite fluence, electric charging and microgravitation. The stratospheric flight experiments are directed to an investigation of the curing polymer matrix under the stratospheric conditions on. The unique combination of low atmospheric pressure, high intensity UV radiation including short wavelength UV and diurnal temperature variations associated with solar irradiation strongly influences the chemical processes in polymeric materials. The first flight experiment with uncured composites was a part of the NASA scientific balloon flight program realised at the NASA stratospheric balloon station in Alice Springs, Australia. A flight cassette installed on payload was lifted with a “zero-pressure” stratospheric balloon filled with Helium. Columbia Scientific Balloon Facility (CSBF) provided the launch, flight telemetry and landing of the balloon and payload. A cassette of uncured composite materials with an epoxy resin matrix was exposed 3 days in the stratosphere (40 km altitude). The second flight experiment was realised in South Australia in 2012, when the cassette was exposed in 27 km altitude. An analysis of the chemical structure of the composites showed, that the space irradiations are responsible for crosslinking of the uncured polymers exposed in the stratosphere. The first prepreg in the world was cured successfully in stratosphere. The investigations were supported by Alexander von Humboldt Foundation, NASA and RFBR (12-08-00970) grants.

  5. Spectrophotometric and colorimetric evaluation of staining of the light cured composite after exposure with different intensities of light curing units

    PubMed Central

    Chandrasekhar, Veeramachaneni; Reddy, L Pramod; Prakash, T Jaya; Rao, G Anitha; Pradeep, M

    2011-01-01

    Aim/Objective: To understand the importance of intensity of light in polymerizing light cured composites and its relation to color stability. Materials and Methods: Forty specimens of composite disc with 3mm diameter and 1.5 mm thick were divided into two groups of 20 samples each. Group1: Twenty samples were cured with a light curing unit of380mw/cm2. Group2: Twenty samples cured with a light curing unit of 680mw/cm2. These polymerized samples were immersed in methylene blue dye for 24hoursand later washed and immersed in absolute alcohol for 24 hours. The amount of color released into absolute alcohol was assessed by spectrophotometric and colorimetric analysis. Results: Results were analyzed for spectrophotometric and colorimetric values by using the Mann-Whitney test. The group cured with low intensity light stained more compared to the group cured with a normal intensity of light. Conclusions: Intensity of light plays a crucial role in staining of the polymerized light cured composite. The intensity of the curing unit has to be maintained in acceptable limits to achieve good clinical results. PMID:22144810

  6. Comparative study of the sealing ability of light-cured versus chemically cured materials placed into furcation perforations.

    PubMed

    Alhadainy, H A; Himel, V T

    1993-09-01

    Two light-cured materials, Vitrebond and Prisma VLC Dycal, were compared with two chemically cured materials, Ketac Fil and Dycal, for ability to seal furcation perforations. Access openings and furcation perforations were prepared in 60 teeth and randomly divided into four equal groups. Furcation perforations were repaired with each of the tested materials, and the access openings were filled with composite resin. After teeth were immersed in 2% erythrocin B dye solution for 10 days, they were sectioned longitudinally and dye penetration was measured. The light-cured materials allowed statistically significant less dye leakage than did the chemically cured materials.

  7. Evaluation of the curing depth of two translucent composite materials using a halogen and two LED curing units.

    PubMed

    Polydorou, Olga; Manolakis, Alexandros; Hellwig, Elmar; Hahn, Petra

    2008-03-01

    This in vitro study evaluated the influence of one halogen and two light-emitting diode (LED) curing units on the curing depth of a conventional hybrid and two translucent resin composites by measuring the Knoop microhardness. In the first part of the study, a conventional hybrid resin composite and three curing units (one halogen: 40 s polymerization time, two LEDs: 10 and 20 s) were used. Ten cylindrical resin composite samples were prepared for each curing unit and each polymerization time tested. After polymerization, the soft part of the samples was removed. The samples were embedded in a polyacrylic resin and separated in the middle towards the direction, top-bottom. On the section plane, Knoop microhardness measurements were performed every 1 mm, starting at 0.5 mm under the surface. In the second part of the study, two translucent resin composites and a conventional hybrid composite resin were cured with the three curing units, and the microhardness was measured as mentioned above. The difference between the curing units tested was found statistically significant (p = 0.0009), as well as the difference between the materials concerning curing depth (p = 0.0001). Both translucent materials achieved microhardness values equal to the 80% of the surface values, in depths 3.5-5.5 mm, depending on the curing units used.

  8. Colour Stability of Heat and Cold Cure Acrylic Resins

    PubMed Central

    Ganesh, P R; Reddy, Madan Mohan; Ebenezar, A.V. Rajesh; Sivakumar, G

    2015-01-01

    Introduction: To evaluate the colour stability of heat and cold cure acrylic resins under simulated oral conditions with different colorants. Materials and Methods: Three different brands of heat cure acrylic resin and two rapid cure auto polymerizing acrylic resin of commercial products such as Trevelon Heat Cure (THC), DPI Heat cure (DHC), Pyrax Heat Cure (PHC), DPI Cold cure (DCC) and Acralyn-R-Cold cure (ACC) have been evaluated for discoloration and colour variation on subjecting it to three different, commonly employed food colorants such as Erythrosine, Tartarizine and Sunset yellow. In order to simulate the oral condition the food colorants were diluted with artificial saliva to the samples taken up for the study. These were further kept in an incubator at 37°C ± 1°C. The UV-visible spectrophotometer has been utilized to evaluate the study on the basis of CIE L* a* b* system. The prepared samples for standard evaluation have been grouped as control group, which has been tested with a white as standard, which is applicable for testing the colour variants. Results: The least colour changes was found to be with Sunset Yellow showing AE* value of 3.55 with heat cure acrylic resin branded as PHC material and the highest colour absorption with Tartarizine showing AE* value of 12.43 in rapid cure autopolymerzing acrylic resin material branded as ACC material. Conclusion: ACC which is a self cure acrylic resin shows a higher colour variation to the tartarizine food coloration. There were not much of discoloration values shown on the denture base resins as the food colorants are of organic azodyes. PMID:25738078

  9. Influence of Layup and Curing on the Surface Accuracy in the Manufacturing of Carbon Fiber Reinforced Polymer (CFRP) Composite Space Mirrors

    NASA Astrophysics Data System (ADS)

    Yang, Zhiyong; Zhang, Jianbao; Xie, Yongjie; Zhang, Boming; Sun, Baogang; Guo, Hongjun

    2017-03-01

    Carbon fiber reinforced polymer, CFRP, composite materials have been used to fabricate space mirror. Usually the composite space mirror can completely replicate the high-precision surface of mould by replication process, but the actual surface accuracy of replicated space mirror is always reduced, still needed further study. We emphatically studied the error caused by layup and curing on the surface accuracy of space mirror through comparative experiments and analyses, the layup and curing influence factors include curing temperature, cooling rate of curing, method of prepreg lay-up, and area weight of fiber. Focusing on the four factors, we analyzed the error influence rule and put forward corresponding control measures to improve the surface figure of space mirror. For comparative analysis, six CFRP composite mirrors were fabricated and surface profile of mirrors were measured. Four guiding control measures were described here. Curing process of composite space mirror is our next focus.

  10. Using cure models for analyzing the influence of pathogens on salmon survival

    USGS Publications Warehouse

    Ray, Adam R; Perry, Russell W.; Som, Nicholas A.; Bartholomew, Jerri L

    2014-01-01

    Parasites and pathogens influence the size and stability of wildlife populations, yet many population models ignore the population-level effects of pathogens. Standard survival analysis methods (e.g., accelerated failure time models) are used to assess how survival rates are influenced by disease. However, they assume that each individual is equally susceptible and will eventually experience the event of interest; this assumption is not typically satisfied with regard to pathogens of wildlife populations. In contrast, mixture cure models, which comprise logistic regression and survival analysis components, allow for different covariates to be entered into each part of the model and provide better predictions of survival when a fraction of the population is expected to survive a disease outbreak. We fitted mixture cure models to the host–pathogen dynamics of Chinook Salmon Oncorhynchus tshawytscha and Coho Salmon O. kisutch and the myxozoan parasite Ceratomyxa shasta. Total parasite concentration, water temperature, and discharge were used as covariates to predict the observed parasite-induced mortality in juvenile salmonids collected as part of a long-term monitoring program in the Klamath River, California. The mixture cure models predicted the observed total mortality well, but some of the variability in observed mortality rates was not captured by the models. Parasite concentration and water temperature were positively associated with total mortality and the mortality rate of both Chinook Salmon and Coho Salmon. Discharge was positively associated with total mortality for both species but only affected the mortality rate for Coho Salmon. The mixture cure models provide insights into how daily survival rates change over time in Chinook Salmon and Coho Salmon after they become infected with C. shasta.

  11. Cure reaction of epoxy resins catalyzed by graphite-based nanofiller

    NASA Astrophysics Data System (ADS)

    Corcione, C. Esposito; Acocella, Maria Rosaria; Giuri, Antonella; Maffezzoli, Alfonso; Guerra, Gaetano

    2015-12-01

    A significant effort was directed to the synthesis of graphene stacks/epoxy nanocomposites and to the analysis of the effect of a graphene precursor on cure reaction of a model epoxy matrix. A comparative thermal analysis of epoxy resins filled with an exfoliated graphite oxide eGO were conducted. The main aim was to understand the molecular origin of the influence of eGO on the Tg of epoxy resins. The higher Tg values previously observed for low curing temperatures, for epoxy resins with graphite-based nanofillers, were easily rationalized by a catalytic activity of graphitic layers on the reaction between the epoxy and amine groups of the resin, which leads to higher crosslinking density in milder conditions. A kinetic analysis of the cure mechanism of the epoxy resin associated to the catalytical activity of the graphite based filler was performed by isothermal DSC measurements. The DSC results showed that the addition of graphite based filler greatly increased the enthalpy of epoxy reaction and the reaction rate, confirming the presence of a catalytic activity of graphitic layers on the crosslinking reaction between the epoxy resin components (epoxide oligomer and di-amine). A kinetic modelling analysis, arising from an auto-catalyzed reaction mechanism, was finally applied to isothermal DSC data, in order to predict the cure mechanism of the epoxy resin in presence of the graphite based nanofiller.

  12. A method for observing gas evolution during plastic laminate cure

    NASA Technical Reports Server (NTRS)

    Nicholls, A. H.

    1969-01-01

    Polyimide, phenolic, and other resins which develop volatiles during laminating or molding cure are studied using optimum cure cycles. The specimen is placed on a platen and sealed in a plastic bag, then heated and observed for gas evolution using a binocular microscope. A cover plate is added to sumulate an autoclave.

  13. Improved method facilitates debulking and curing of phenolic impregnated asbestos

    NASA Technical Reports Server (NTRS)

    Gaines, P.

    1966-01-01

    Workpieces covered with phenolic impregnated asbestos tape and then wrapped with a specified thickness of nylon yarn under pressure, are debulked and cured in a standard oven. This method of debulking and curing is used in the fabrication of ablative chambers for the Gemini and Apollo attitude control engines.

  14. Cure cycle evaluation for multilayer printed wiring boards

    SciTech Connect

    Lula, J.W.

    1980-06-01

    The cure cycle for multilayer printed wiring boards (PWBs) made from general-puspore, fire-retardant epoxy/glass (GF) material has been evaluated for the optimum delamination resistance at soldering temperatures. The results that, for the epoxy resin system used to manufacture multilayer PWBs at Bendix Kansas City, a wide range of cure cycle variations has a minimal effect on delamination resistance.

  15. Teaching as Cure and Care: A Therapeutic Metaphor.

    ERIC Educational Resources Information Center

    Elias, John L.

    1990-01-01

    Uses the curing and caring aspects of medicine as an analogy for what education can be. Observes that the divinity expressed through medicine's ability to cure and care for people also can be expressed through teaching when it attempts to eliminate ignorance, prejudice, and misinformation. (DB)

  16. Computerized Ultrasound Risk Evaluation (CURE): First Clinical Results

    NASA Astrophysics Data System (ADS)

    Duric, N.; Littrup, P.; Rama, O.; Holsapple, E.

    The Karmanos Cancer Institute has developed an ultrasound (US) tomography system, known as Computerized Ultrasound Risk Evaluation (CURE), for detecting and evaluating breast cancer, with the eventual goal of providing improved differentiation of benign masses from cancer. We report on our first clinical findings with CURE.

  17. Mathematical Model of Raw Hide Curing with Brine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The most common method of preserving raw hides is brine curing with sodium chloride. However, this process has three important disadvantages: first, the length of time that it takes, which is a minimum of 18 hours; second, the insufficient degree of curing reached in some hides due to an overload a...

  18. From scientific discovery to cures: bright stars within a galaxy.

    PubMed

    Williams, R Sanders; Lotia, Samad; Holloway, Alisha K; Pico, Alexander R

    2015-09-24

    We propose that data mining and network analysis utilizing public databases can identify and quantify relationships between scientific discoveries and major advances in medicine (cures). Further development of such approaches could help to increase public understanding and governmental support for life science research and could enhance decision making in the quest for cures.

  19. Mental Retardation: The Search for Cures. Research Monograph Number 7.

    ERIC Educational Resources Information Center

    Menolascino, Frank J.; Neman, Ronald

    The booklet describes the Association for Retarded Citizens' (ARC's) goal of coordinating efforts to seek a cure for mental retardation. Cures are defined as any intervention that would significantly increase intellectual functioning and adaptive behavior beyond the upper level of retardation. It is explained that because of the variety of causes…

  20. The coating curing properties study using terahertz time domain spectroscopy

    NASA Astrophysics Data System (ADS)

    Ren, Jiaojiao; Zhao, Duo; Li, Lijuan

    2015-10-01

    Coating curing curve is one of the most important methods to reflect the coating curing properties. It is of great significance for the coating curing properties. In this paper, by using the reflective Terahertz (THz) time-domain spectroscope technique, the curing properties of coating with different thicknesses are studied. Three different parameters used for studying the properties of coating curing curve are proposed in this paper. They are respectively the differential time of flight, power spectrum and amplitude for reflective THz time-domain waveform. In this paper, two kinds of coating (with different thicknesses) curing properties curves are established and the relative errors from three parameter analysis methods are compared respectively. This study shows that the study on coating curing properties curves by using the power spectrum of reflective THz time-domain waveform is superior to the amplitude parameter method. But for the thick coating, the differential time of flight for the reflective THz time-domain waveform can also better reflect the coating curing properties.

  1. Shear Bond Strength of Acidic Primer, Light-Cure Glass Ionomer, Light-Cure and Self Cure Composite Adhesive Systems - An In Vitro Study

    PubMed Central

    D, Krishnakanth Reddy; V, Kishore M S; Safeena, Safeena

    2013-01-01

    Background: The purpose of this study was to determine shear bond strength and the effect on the bracket/ adhesive failure mode when an acidic primer and other etchants were used to condition the enamel surface before bonding. Materials & Methods: Group I: Brackets bonded with Ultimate cure-on-light Light-cure composite adhesive system. Group II: Brackets bonded with Ortho-one no-mix. Self-cure composite adhesive system. Group III: Brackets bonded with Light-cure glass ionomer adhesive system. Group IV: Brackets bonded with Transbond plus self etching primer. Results: The results of this study indicated that the shear bond strength when using Transbond plus self etching primer showed the highest bond strength Group- IV(8.69 2.54 MPa) followed by Ultimate cure-on-light Group-I (8.62 1.84 MPa), Ortho-one no-mix (Bisco Inc. USA)Group-II (8.07 1.72 MPa), and least bond strength was seen in G.C. Fuji Ortho L.C. Group-III (6.01 1.6) MPa Conclusion: Use of self etching primer saves chairside time and satisfactory high bond strength was obtained. Care should be taken during debonding of ceramic brackets How to cite this article: Reddy K D, Kishore M S V, Safeena S. Shear Bond Strength of Acidic Primer, Light-Cure Glass Ionomer, Light-Cure and Self Cure Composite Adhesive Systems - An In Vitro Study. J Int Oral Health 2013; 5(3):73-78. PMID:24155606

  2. Rat subchronic inhalation study of smoke from cigarettes containing flue-cured tobacco cured either by direct-fired or heat-exchanger curing processes.

    PubMed

    Kinsler, Steven; Pence, Deborah H; Shreve, W Keith; Mosberg, Arnold T; Ayres, Paul H; Sagartz, John W

    2003-07-01

    A subchronic, nose-only inhalation study compared the effects of mainstream smoke from a cigarette containing 100% flue-cured tobacco cured by a direct-fired process to that of a cigarette containing 100% flue-cured tobacco cured by a heat exchanger process. The tobaccos and mainstream smoke from tobaccos cured by the heat exchanger process have been shown to have significantly lower levels of tobacco-specific nitrosamines than tobaccos cured by a direct-fired process. Male and female rats were exposed for 1 h/day, 5 days/wk, for 13 wk to mainstream smoke at 0, 0.06, 0.20, or 0.80 mg wet total particulate matter per liter of air. Clinical signs, body and organ weights, clinical chemistry, hematology, carboxyhemoglobin, serum nicotine, plethysmography, gross pathology, and histopathology were determined. When histologic changes resulting from exposure to smoke from the two types of cigarettes were compared, the only significant difference was increased epithelial hyperplasia of the anterior nasal cavity in males in the high-exposure group for the heat-exchanger cigarette. At the end of the exposure period, subsets of rats from each group were maintained without smoke exposures for an additional 13 wk (recovery period). At the end of the recovery period, there were no statistically significant differences in histopathological findings observed between the heat-exchanger-cured tobacco cigarette when compared to the direct-fired cured tobacco cigarette. The complete toxicological assessment in this study of heat exchanger and direct-fired tobaccos suggests no overall biologically significant differences between the two cigarettes.

  3. Use of light-curing units in orthodontics.

    PubMed

    Goyal, Amit; Hurkadle, Jyothikiran; Magegowda, Shivalinga; Bhatia, Pankaj

    2013-08-01

    Because of their wide field of applications, light-curing units are now indispensable for orthodontists and general dentists; thus, it is important to be familiar with the various types of light-curing units, their history, specifications, advantages, and disadvantages. For this review, a search of the PubMed database (from 1966 to March 2010) was conducted using the search term "curing lights orthodontics". Eligibility of the selected studies was determined by reading the abstracts of articles identified by the search. All the articles that met the inclusion criteria were selected, and the articles collected. The reference lists of the retrieved articles were also hand searched for any applicable studies that might have been missed in the database searches. When selecting curing lights for an office, many variables need to be considered. Armed with knowledge about each curing-light category, orthodontists can evaluate their unique practice style and select the appropriate light/lights.

  4. 7 CFR 30.38 - Class 3; air-cured types and groups.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... produced principally in the Green River section of Kentucky. (g) Type 37. That type of air-cured or sun-cured tobacco commonly known as Virginia Sun-cured, Virginia Sun and Air-cured, or Dark Air-cured...

  5. 7 CFR 30.38 - Class 3; air-cured types and groups.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... produced principally in the Green River section of Kentucky. (g) Type 37. That type of air-cured or sun-cured tobacco commonly known as Virginia Sun-cured, Virginia Sun and Air-cured, or Dark Air-cured...

  6. 7 CFR 30.38 - Class 3; air-cured types and groups.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... produced principally in the Green River section of Kentucky. (g) Type 37. That type of air-cured or sun-cured tobacco commonly known as Virginia Sun-cured, Virginia Sun and Air-cured, or Dark Air-cured...

  7. 7 CFR 30.38 - Class 3; air-cured types and groups.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... produced principally in the Green River section of Kentucky. (g) Type 37. That type of air-cured or sun-cured tobacco commonly known as Virginia Sun-cured, Virginia Sun and Air-cured, or Dark Air-cured...

  8. Cure models for the analysis of time-to-event data in cancer studies.

    PubMed

    Jia, Xiaoyu; Sima, Camelia S; Brennan, Murray F; Panageas, Katherine S

    2013-11-01

    In settings when it is biologically plausible that some patients are cured after definitive treatment, cure models present an alternative to conventional survival analysis. Cure models can inform on the group of patients cured, by estimating the probability of cure, and identifying factors that influence it; while simultaneously focusing on time to recurrence and associated factors for the remaining patients.

  9. Stress evolution in a conductive adhesive during curing and cooling

    NASA Astrophysics Data System (ADS)

    Mei, Yuhai

    2000-10-01

    There is increasing interest in using conductive adhesives, which are composites of polymers and conductive fillers, as replacements for solder in different types of microelectronic assemblies. However, conductive adhesives still suffer from several deficiencies, such as unstable electrical conductivity and inadequate adhesion. The reliability of the conductive adhesive joints is always one of the major considerations during their design and operation, and the curing and thermal stresses generated in polymers and composites during curing, cooling and thermal cycling play a very important role in determining reliability. Because of the mismatch in the mechanical properties between the conductive adhesive and the substrate, appreciable curing and thermal stress is generated during manufacturing, which may be detrimental to the reliability of conductive adhesive joints. In this dissertation, an interactive linear viscoelastic model which considers interaction between the initial gel network and the other networks that form during curing is proposed to simulate stress and volume shrinkage during the thermoset curing process, and an effective method for measuring volume shrinkage during the thermoset cure is developed. A systematic experimental study of the material properties of the conductive adhesive and its epoxy matrix during the curing and cooling processes has been conducted. Based on these experimental data, stresses generated during several spatially homogeneous curing and cooling processes of the conductive adhesive and its epoxy matrix are also calculated. It is found that the conductive adhesive possesses mechanical properties which are substantially different from those of the constituents, and that the conductive adhesive has a relaxation process which is similar to its matrix and generates appreciable curing and thermal stresses during curing and cooling. Finally, a processing procedure designed to provide desired residual stresses is discussed.

  10. HIV Cure Strategies: How Good Must They Be to Improve on Current Antiretroviral Therapy?

    PubMed Central

    Sax, Paul E.; Sypek, Alexis; Berkowitz, Bethany K.; Morris, Bethany L.; Losina, Elena; Paltiel, A. David; Kelly, Kathleen A.; Seage, George R.; Walensky, Rochelle P.; Weinstein, Milton C.; Eron, Joseph; Freedberg, Kenneth A.

    2014-01-01

    Background We examined efficacy, toxicity, relapse, cost, and quality-of-life thresholds of hypothetical HIV cure interventions that would make them cost-effective compared to life-long antiretroviral therapy (ART). Methods We used a computer simulation model to assess three HIV cure strategies: Gene Therapy, Chemotherapy, and Stem Cell Transplantation (SCT), each compared to ART. Efficacy and cost parameters were varied widely in sensitivity analysis. Outcomes included quality-adjusted life expectancy, lifetime cost, and cost-effectiveness in dollars/quality-adjusted life year ($/QALY) gained. Strategies were deemed cost-effective with incremental cost-effectiveness ratios <$100,000/QALY. Results For patients on ART, discounted quality-adjusted life expectancy was 16.4 years and lifetime costs were $591,400. Gene Therapy was cost-effective with efficacy of 10%, relapse rate 0.5%/month, and cost $54,000. Chemotherapy was cost-effective with efficacy of 88%, relapse rate 0.5%/month, and cost $12,400/month for 24 months. At $150,000/procedure, SCT was cost-effective with efficacy of 79% and relapse rate 0.5%/month. Moderate efficacy increases and cost reductions made Gene Therapy cost-saving, but substantial efficacy/cost changes were needed to make Chemotherapy or SCT cost-saving. Conclusions Depending on efficacy, relapse rate, and cost, cure strategies could be cost-effective compared to current ART and potentially cost-saving. These results may help provide performance targets for developing cure strategies for HIV. PMID:25397616

  11. Numerical natural rubber curing simulation, obtaining a controlled gradient of the state of cure in a thick-section part

    NASA Astrophysics Data System (ADS)

    El Labban, A.; Mousseau, P.; Bailleul, J. L.; Deterre, R.

    2007-04-01

    Although numerical simulation has proved to be a useful tool to predict the rubber vulcanization process, few applications in the process control have been reported. Because the end-use rubber properties depend on the state of cure distribution in the parts thickness, the prediction of the optimal distribution remains a challenge for the rubber industry. The analysis of the vulcanization process requires the determination of the thermal behavior of the material and the cure kinetics. A nonisothermal vulcanization model with nonisothermal induction time is used in this numerical study. Numerical results are obtained for natural rubber (NR) thick-section part curing. A controlled gradient of the state of cure in the part thickness is obtained by a curing process that consists not only in mold heating phase, but also a forced convection mold cooling phase in order to stop the vulcanization process and to control the vulcanization distribution. The mold design that allows this control is described. In the heating phase, the state of cure is mainly controlled by the chemical kinetics (the induction time), but in the cooling phase, it is the heat diffusion that controls the state of cure distribution. A comparison among different cooling conditions is shown and a good state of cure gradient control is obtained.

  12. Effect of three types of light-curing units on 5-year colour changes of light-cured composite.

    PubMed

    Tak, Onjen; Altintas, Subutay Han; Ozturk, Nilgun; Usumez, Aslihan

    2009-03-01

    The purpose of this study was to determine colour changes in a composite cured with tungsten-halogen, light-emitting diode (LED) or a plasma arc after 5 years. Five specimens 10 mm in diameter and 2 mm in height were prepared using Hybrid (Clearfil AP-X) composite for each test group. The corresponding specimens were cured with a tungsten-halogen curing light, a LED unit or with a plasma arc. Specimens were stored in light-proof boxes for 5 years after the curing procedure to avoid further exposure to light and stored in 37 degrees C in 100% humidity. Colorimetric values of the specimens immediately after curing and after 5 years were measured using colorimeter. The DeltaE*( ab ) values varied significantly depending on the curing unit used (p < 0.001). Curing time did not affect the colour changes of the specimens (p = 0.4). The results of this study suggest that composite materials undergo measurable changes due to the curing unit exposure.

  13. Role of Virechana Karma in cure and prevention of recurrence of Vicharchika (Eczema)

    PubMed Central

    Kaur, Mandip; Chandola, Harimohan

    2012-01-01

    Mandip and Chandola reported that administration of Rasayana (Guduchi and Bhringaraja) after Koshtha Shuddhi with Aragvadha Hima and simultaneous giving of Shirishadi decoction orally and applying of Snuhyadi Lepa externally provided complete remission to 22.6% patients of Vicharchika (Eczema) and checked the recurrences of the disease in the 89.5% patients. As in this group, cure rate was not up to the expectation; therefore, it was thought desirable to see whether performing of Virechana Karma instead of Koshtha Shuddhi prior to the administration of the above drugs enhances the cure rate for the Vicharchika (Eczema) patients. For the present study, 39 patients of Vicharchika (Eczema) were registered, of which 32 patients completed the full course of the treatment. These patients were given Virechana after preparing with the proper internal Snehana, Abhyanga, and Svedana as per classical method. After the Samsarjana Krama, they were administered the Shirishadi decoction and Guduchi-Bhringraja Rasayana powder orally with simultaneous local application of Snuhyadi Lepa on the eczematous lesions. The results of this study showed that when Virechana Karma was performed prior to the administration of Guduchi-Bhringaraja Rasayana and Shirishadi decoction orally and SnuhyadiLepa externally, it not only increased the cure rate to 81.3% in the patients of Vicharchika (Eczema) but also checked the recurrences to great extent as only negligible number of the patients reported the recurrence. PMID:23723667

  14. Novel Multifunctional Organic-Inorganic Hybrid Curing Agent with High Flame-Retardant Efficiency for Epoxy Resin.

    PubMed

    Tan, Yi; Shao, Zhu-Bao; Chen, Xue-Fang; Long, Jia-Wei; Chen, Li; Wang, Yu-Zhong

    2015-08-19

    A novel multifunctional organic-inorganic hybrid was designed and prepared based on ammonium polyphosphate (APP) by cation exchange with diethylenetriamine (DETA), abbreviated as DETA-APP. Then DETA-APP was used as flame-retardant curing agent for epoxy resin (EP). Curing behavior, including the curing kinetic parameters, was investigated by differential scanning calorimetry (DSC) and X-ray photoelectron spectroscopy (XPS). The flame retardance and burning behavior of DETA-APP cured EP were also evaluated. The limiting oxygen index (LOI) value of DETA-APP/EP was enhanced to 30.5% with only 15 wt % of DETA-APP incorporated; and the UL-94 V-0 rating could be easily passed through with only 10 wt % of the hybrid. Compared with DETA/EP, the peak-heat release rate (PHRR), total heat release (THR), total smoke production (TSP), and peak-smoke production release (SPR) of DETA-APP/EP (15 wt % addition), obtained from cone calorimetry, were dropped by 68.3, 79.3, 79.0, and 30.0%, respectively, suggesting excellent flame-retardant and smoke suppression efficiency. The flame-retardant mechanism of DETA-APP/EP has been investigated comprehensively. The results of all the aforementioned studies distinctly confirmed that DETA-APP was an effective flame-retardant curing agent for EP.

  15. The natural cure of coronary heart disease.

    PubMed

    Withnell, Allan

    2003-01-01

    Following the development of coronary heart disease in 1989 I was introduced to an alumnus of the Pritikin Longevity Center in California and I adopted the regimen of diet and exercise. Within five months I was able to abandon all medication and was symptom free. My medical colleagues maintained that, because I had recovered, the Consultant's diagnosis must have been wrong--there can be no cure of coronary heart disease by lifestyle changes alone. As a result of my experience I decided to review the literature to study the natural history of coronary heart disease. My findings strongly suggest that the increase in incidence in the last hundred years from virtually nil to epidemic proportions is due to lifestyle changes and that the disease can be reversed. I list a number of doctors who have influenced large numbers of people to change their lifestyles with great success. They have utilised mainly plant-based diets whose composition is the same or similar to that which Pritikin originally used and which is still extant at the Longevity Center. I conclude by suggesting that the possibility of reversal of coronary heart disease has profound implications for its treatment with enormous potential savings for the National Health Service.

  16. Development of a resin curing model for UV nanoimprint.

    PubMed

    Lee, Jin Woo; Cho, Dong-Woo

    2005-10-01

    UV nanoimprint lithography uses UV light as an energy source. It is performed at room temperature and low pressure, and has its own merits as compared to thermal nanoimprint. In this paper, a measurement system was developed to measure the degree of resin curing in UV nanoimprint to improve our understanding of the resin solidification phenomenon. A curing model was then established based on the measurement results. The measurement system measured the degree of cure in real time and was composed of a Fourier transform infrared spectroscopy system, a UV light source, and an optical guide. Also, new UV-curable resins that had low viscosity values were developed for the UV nanoimprint process, and imprint tests using these resins were performed successfully. The curing model considered the UV irradiation time, power, and curing temperature, which are important parameters in the UV nanoimprint process. The degree of cure had an exponential relation to UV irradiation time, power, and temperature; thus, the curing model was expressed as an exponential function of the UV irradiation time, power, and temperature. The developed model was verified for various UV-curable resins.

  17. Electron Beam Cured Epoxy Resin Composites for High Temperature Applications

    NASA Technical Reports Server (NTRS)

    Janke, Christopher J.; Dorsey, George F.; Havens, Stephen J.; Lopata, Vincent J.; Meador, Michael A.

    1997-01-01

    Electron beam curing of Polymer Matrix Composites (PMC's) is a nonthermal, nonautoclave curing process that has been demonstrated to be a cost effective and advantageous alternative to conventional thermal curing. Advantages of electron beam curing include: reduced manufacturing costs; significantly reduced curing times; improvements in part quality and performance; reduced environmental and health concerns; and improvement in material handling. In 1994 a Cooperative Research and Development Agreement (CRADA), sponsored by the Department of Energy Defense Programs and 10 industrial partners, was established to advance the electron beam curing of PMC technology. Over the last several years a significant amount of effort within the CRADA has been devoted to the development and optimization of resin systems and PMCs that match the performance of thermal cured composites. This highly successful materials development effort has resulted in a board family of high performance, electron beam curable cationic epoxy resin systems possessing a wide range of excellent processing and property profiles. Hundreds of resin systems, both toughened and untoughened, offering unlimited formulation and processing flexibility have been developed and evaluated in the CRADA program.

  18. Comprehensive study of dynamic curing effect on tablet coating structure.

    PubMed

    Gendre, Claire; Genty, Muriel; da Silva, Julio César; Tfayli, Ali; Boiret, Mathieu; Lecoq, Olivier; Baron, Michel; Chaminade, Pierre; Péan, Jean Manuel

    2012-08-01

    The dissolution method is still widely used to determine curing end-points to ensure long-term stability of film coatings. Nevertheless, the process of curing has not yet been fully investigated. For the first time, joint techniques were used to elucidate the mechanisms of dynamic curing over time from ethylcellulose (Aquacoat)-based coated tablets. X-ray micro-computed tomography (XμCT), Near Infrared (NIR), and Raman spectroscopies as well as X-ray microdiffraction were employed as non-destructive techniques to perform direct measurements on tablets. All techniques indicated that after a dynamic curing period of 4h, reproducible drug release can be achieved and no changes in the microstructure of the coating were any longer detected. XμCT analysis highlighted the reduced internal porosity, while both NIR and Raman measurements showed that spectral information remained unaltered after further curing. X-ray microdiffraction revealed densification of the coating layer with a decrease in the overall coating thickness of about 10 μm as a result of curing. In addition, coating heterogeneity attributed to cetyl alcohol was observed from microscopic images and Raman analysis. This observation was confirmed by X-ray microdiffraction that showed that crystalline cetyl alcohol melted and spread over the coating surface with curing. Prior to curing, X-ray microdiffraction also revealed the existence of two coating zones differing in crystalline cetyl alcohol and sodium lauryl sulfate concentrations which could be explained by migration of these constituents within the coating layer. Therefore, the use of non-destructive techniques allowed new insights into tablet coating structures and provided precise determination of the curing end-point compared to traditional dissolution testing. This thorough study may open up new possibilities for process and formulation control.

  19. Depth of cure of bulk fill composites with monowave and polywave curing lights

    PubMed Central

    Menees, Timothy S.; Lin, Chee Paul; Kojic, Dave D.; Burgess, John O.; Lawson, Nathaniel C.

    2016-01-01

    Purpose To measure and compare the depth of cure (DOC) of two bulk fill composite resins using a monowave and polywave light curing unit (LCU) according to ISO 4049 and using custom tooth molds. Methods The DOC of Tetric Evoceram Bulk Fill (Ivoclar Vivadent) and Filtek Bulk Fill Posterior (3M ESPE) were measured using a monowave LED LCU (Elipar S10 / 3M ESPE) and a polywave LED LCU (Bluephase G2 / Ivoclar Vivadent). Metal molds were used to fabricate 10 mm long DOC specimens (n=10) according to ISO 4049. Uncured composite material was scraped away with a plastic instrument and half the length of remaining composite was measured as the DOC. Custom tooth molds were fabricated by preparing >10mm long square-shaped (4 × 4 mm) holes into the mesial/distal surfaces of extracted human molars. Composite resin was placed into one end of the prepared tooth and light polymerized. Uncured composite resin was removed from the opposite side from which the tooth was irradiated and the tooth was sectioned mesio-distally. Half the length of remaining cured composite was measured as the DOC. Data were analyzed by three-way ANOVA (alpha=0.05) for factors material, LCU, and mold. Results The main effect LCU was not significant (p=.58). The interaction effect between material × mold was significant (p=.0001). The DOC of the composites differed significantly only with the stainless steel mold in which Tetric Evoceram Bulk Fill showed a deeper DOC than Filtek Bulk Fill Posterior (4.03 ± 0.14 vs 3.56 ± 0.38 mm, p<.0001). PMID:26897758

  20. Acute promyelocytic leukaemia: novel insights into the mechanisms of cure.

    PubMed

    de Thé, Hugues; Chen, Zhu

    2010-11-01

    The fusion oncogene, promyelocytic leukaemia (PML)-retinoic acid receptor-α (RARA), initiates acute promyelocytic leukaemia (APL) through both a block to differentiation and increased self-renewal of leukaemic progenitor cells. The current standard of care is retinoic acid (RA) and chemotherapy, but arsenic trioxide also cures many patients with APL, and an RA plus arsenic trioxide combination cures most patients. This Review discusses the recent evidence that reveals surprising new insights into how RA and arsenic trioxide cure this leukaemia, by targeting PML-RARα for degradation. Drug-triggered oncoprotein degradation may be a strategy that is applicable to many cancers.

  1. Cure-dependent Viscoelastic Poisson’s Ratio of Epoxy

    DTIC Science & Technology

    2007-01-26

    Faivre S, Roy LE, Trotignon JP, Verdu J (1996) Mechanical properties of thermosets. Part I. Tensile properties of an anhydride cured epoxy . J Mater...Experimental Mechanics (2007) 47: 237–249 DOI 10.1007/s11340-006-9013-9 Cure -dependent Viscoelastic Poisson’s Ratio of Epoxy D.J. O’Brien · N.R...Abstract The evolution of the lateral contraction ratio of two commercial (high and low temperature cure ) epoxy resins is studied in uniaxial tension

  2. Mathematical Model Of Curing Behavior Of A Polymer

    NASA Technical Reports Server (NTRS)

    Loomis, Willard C.; Beyer, Rodney B.; Liu, Edmund K. S.

    1995-01-01

    Mathematical model predicts selected aspects of chemical, thermal and mechanical responses of polymeric liner and propellant materials during curing process. Predictions made both prior to processing and during process in quasi-real time. Developed specifically for use in designing and analyzing process in which bondline materials (including polymeric liners) and propellant cast and cured in rocket motor. With modifications, model applicable to curing of other polymeric materials. Further development may provide direct "in-line" program for calculations, including comparisons, in real time. This will constitute basis for more sophisticated control of process.

  3. Mechanism of Monuron-Accelerated Dicyandiamide Cure of Epoxy Resins

    DTIC Science & Technology

    1981-07-01

    ÜBBSBBffl^w^r’r^^—. ■ «Mmfifißmwww-tr- oo o m* AMMRC TR 81-34 AD MECHANISM OF < MONURON-ACCELERATED ^ DICYANDIAMIDE CURE OF...REPORT NJJMMR RC-TR-81-34 2. GOVT ACCESSION NO. 4. TITLE fand Submit) AV-A/^if^ , MECHANISM OF MONURON-ACCELERATED DICYANDIAMIDE CURE OF EPOXY...4-chJqTophenyl)-tI,,N,-dimethylurea, >is the ability of this class of aryl ureas to accelerate the dicyandiamide (Dicy) cure of epoxy resins

  4. Micromechanical properties of veneer luting resins after curing through ceramics.

    PubMed

    Oztürk, Elif; Hickel, Reinhard; Bolay, Sükran; Ilie, Nicoleta

    2012-02-01

    The aim of this study was to assess the performance of light-cured luting resin after curing under the ceramic restoration in comparison to dual-cured luting resin, by evaluating the micromechanical properties. Two hundred seventy thin luting composite films of ca. 170 μm in thickness were prepared by using two light-cured luting resins (Variolink Veneer, Ivoclar Vivadent; RelyX Veneer, 3M ESPE) and a dual-cured luting resin (Variolink II, Ivoclar Vivadent). The composites were cured by using a LED-unit (Bluephase®, Ivoclar Vivadent) with three different curing times (10, 20, and 30 s) under two ceramics (IPS e.max Press, Ivoclar Vivadent; IPS Empress® CAD, Ivoclar Vivadent) of different thicknesses (0, 0.75, and 2 mm). Forty-five groups were included, each containing six thin films. The samples were stored after curing for 24 h at 37°C by maintaining moisture conditions with distilled water. Micromechanical properties of the composites were measured with an automatic microhardness indenter (Fisherscope H100C, Germany). For each sample, ten indentations were made, thus totalizing 60 measurements per group. Micromechanical properties of the luting resins were statistically analyzed (SPSS 17.0). Significant differences were observed between the micromechanical properties of the luting resins (p < 0.05). Variolink II showed the highest values in modulus of elasticity (E = 11 ± 0.5)* and Vickers hardness (HV = 48.2 ± 3.2)* and the lowest values in creep (Cr = 4.3 ± 0.1)* and elastic-plastic deformation (We/Wtot = 38.6 ± 0.7)* followed by RelyX Veneer (E = 6.9 ± 0.3, HV = 33 ± 2.5, Cr = 4.6 ± 0.2, We/Wtot = 41.8 ± 1.0)* and Variolink Veneer (E = 4.4 ± 0.4, HV = 20.1 ± 2.6, Cr = 5 ± 0.2, We/Wtot = 43.7 ± 1.3)*. Dual-cured luting resin expressed higher values in the micro-mechanical properties compared to the light-cured luting resins. The effect of luting resin type on the micromechanical properties of the luting resins was higher than the effect of

  5. Micro-leakage of a Fissure Sealant Cured Using Quartz-tungsten-halogen and Plasma Arc Light Curing Units

    PubMed Central

    Bahrololoomi, Zahra; Soleimani, Ali Asghar; Jafari, Najmeh; Varkesh, Bentolhoda

    2014-01-01

    Background and aims. Newer curing units such as plasma arc can polymerize the sealants in much shorter curing times. The aim of this study was to compare the effect of two different curing units on the micro-leakage of a fissure sealant material. Materials and methods. Sixty two extracted premolars without caries were randomly divided into two groups of 31 samples. Occlusal surfaces of all teeth were cleansed. Then, teeth surfaces were etched by 37% phosphoric acid. After rinsing and drying, occlusal surfaces of teeth were sealed by a fissure sealant. The sealant was then cured using either a halogen light curing unit or a plasma arc curing light. After sealing, the teeth were thermocycled for 500 cycles. The teeth were then sectioned and examined for micro-leakage. Statistical analyses were performed with Mann-Whitney test. Results. There was no significant difference between two groups regarding micro-leakage (P = 0.42). Conclusion. Results showed that there was no significant difference between two different curing units. Therefore, plasma arc unit might be a useful alternative for sealant polymerization. PMID:25587389

  6. Micro-leakage of a Fissure Sealant Cured Using Quartz-tungsten-halogen and Plasma Arc Light Curing Units.

    PubMed

    Bahrololoomi, Zahra; Soleimani, Ali Asghar; Jafari, Najmeh; Varkesh, Bentolhoda

    2014-01-01

    Background and aims. Newer curing units such as plasma arc can polymerize the sealants in much shorter curing times. The aim of this study was to compare the effect of two different curing units on the micro-leakage of a fissure sealant material. Materials and methods. Sixty two extracted premolars without caries were randomly divided into two groups of 31 samples. Occlusal surfaces of all teeth were cleansed. Then, teeth surfaces were etched by 37% phosphoric acid. After rinsing and drying, occlusal surfaces of teeth were sealed by a fissure sealant. The sealant was then cured using either a halogen light curing unit or a plasma arc curing light. After sealing, the teeth were thermocycled for 500 cycles. The teeth were then sectioned and examined for micro-leakage. Statistical analyses were performed with Mann-Whitney test. Results. There was no significant difference between two groups regarding micro-leakage (P = 0.42). Conclusion. Results showed that there was no significant difference between two different curing units. Therefore, plasma arc unit might be a useful alternative for sealant polymerization.

  7. Balancing cure and long-term risks in acute lymphoblastic leukemia.

    PubMed

    Silverman, Lewis B

    2014-12-05

    Cure rates for children and adolescents with acute lymphoblastic leukemia (ALL) have improved dramatically over the last few decades. With this success has come increasing recognition of the adverse late effects of treatment. The significant long-term sequelae in the earliest cohort of long-term survivors treated in the 1970s and 1980s are well documented. To reduce the incidence of these late effects, the majority of pediatric patients treated on more contemporary regimens receive less intensive treatment than did those treated 30-40 years ago. However, current therapies are not risk free; children treated with contemporary regimens remain at risk for developing long-term toxicities, including cardiac dysfunction, osteonecrosis, neurocognitive impairment, and second malignant neoplasms. One of the great challenges facing clinical investigators today is to identify interventions that will reduce the frequency and severity of long-term toxicities without adversely affecting cure rates. The use of dexrazoxane as a cardioprotectant (to prevent anthracycline-associated cardiotoxicity) and alternate-week dosing of dexamethasone (to reduce the risk of osteonecrosis) are examples of 2 such successful strategies. This article provides an overview of the long-term toxicities associated with current therapies and reviews results of clinical trials designed to minimize the burden of cure in long-term survivors.

  8. Investigation of lignite and firewood co-combustion in a furnace for tobacco curing application

    SciTech Connect

    Nakorn Tippayawong; Chutchawan Tantakitti; Satis Thavornun

    2006-07-01

    Co-combustion of lignite and firewood was investigated for an application in tobacco curing industry in Northern Thailand. Extensive experiments have been carried out in a newly developed furnace suitable for small curing unit, in place of locally made furnace. The aim of this investigation is to evaluate the performance of the combustion chamber in the required thermal output range for tobacco curing and to examine the influence of fuel feed rate, fuel mixture ratio and air staging on the combustion and emission characteristics of the furnace during steady state operation. Their effects are characterized in terms of the observed variations of temperature distributions, emissions of CO, SO{sub 2}, CO{sub 2}, O{sub 2} and combustion efficiency. Co-firing of firewood and lignite has been found to exhibit acceptable temperature distribution, high combustion efficiency and low emissions over a wide thermal output span. Stable operation at low (50 kW) and high (150 kW) thermal output was achieved with average CO and SO{sub 2} content in flue gas typically below 1400 and 100 ppm, respectively. Under the conditions considered, it was showed that the fuel feed rate had greater influence on combustion and emissions than firewood and lignite mixture ratio and air staging.

  9. The effect of curing light and chemical catalyst on the degree of conversion of two dual cured resin luting cements.

    PubMed

    Souza-Junior, Eduardo José; Prieto, Lúcia Trazzi; Soares, Giulliana Panfiglio; Dias, Carlos Tadeu dos Santos; Aguiar, Flávio Henrique Baggio; Paulillo, Luís Alexandre Maffei Sartini

    2012-01-01

    The aim of this study was to evaluate the influence of different curing lights and chemical catalysts on the degree of conversion of resin luting cements. A total of 60 disk-shaped specimens of RelyX ARC or Panavia F of diameter 5 mm and thickness 0.5 mm were prepared and the respective chemical catalyst (Scotchbond Multi-Purpose Plus or ED Primer) was added. The specimens were light-cured using different curing units (an argon ion laser, an LED or a quartz-tungsten-halogen light) through shade A2 composite disks of diameter 10 mm and thickness 2 mm. After 24 h of dry storage at 37°C, the degree of conversion of the resin luting cements was measured by Fourier-transformed infrared spectroscopy. For statistical analysis, ANOVA and the Tukey test were used, with p ≤ 0.05. Panavia F when used without catalyst and cured using the LED or the argon ion laser showed degree of conversion values significantly lower than RelyX ARC, with and without catalyst, and cured with any of the light sources. Therefore, the degree of conversion of Panavia F with ED Primer cured with the quartz-tungsten-halogen light was significantly different from that of RelyX ARC regardless of the use of the chemical catalyst and light curing source. In conclusion, RelyX ARC can be cured satisfactorily with the argon ion laser, LED or quartz-tungsten-halogen light with or without a chemical catalyst. To obtain a satisfactory degree of conversion, Panavia F luting cement should be used with ED Primer and cured with halogen light.

  10. Effect of curing mode on the micro-mechanical properties of dual-cured self-adhesive resin cements.

    PubMed

    Ilie, Nicoleta; Simon, Alexander

    2012-04-01

    Light supplying to luting resin cements is impeded in several clinical situations, causing us to question whether materials can properly be cured to achieve adequately (or adequate) mechanical properties. The aim of this study was therefore to analyse the effect of light on the micro-mechanical properties of eight popular dual-cured self-adhesive resin cements by comparing them with two conventional, also dual-cured, resin cements. Four different curing procedures were applied: auto-polymerisation (dark curing) and light curing (LED unit, Freelight 2, 20 s) by applying the unit directly on the samples' surface, at a distance of 5 and 10 mm. Twenty minutes after curing, the samples were stored for 1 week at 37°C in a water-saturated atmosphere. The micro-mechanical properties-Vickers hardness, modulus of elasticity, creep and elastic/plastic deformation-were measured. Data were analysed with multivariate ANOVA followed by Tukey's test and partial eta-squared statistics (p < 0.05). A very strong influence of the material as well as filler volume and weight on the micro-mechanical properties was measured, whereas the influence of the curing procedure and type of cement-conventional or self-adhesive-was generally low. The influence of light on the polymerisation process was material dependent, with four different behaviour patterns to be distinguished. As a material category, significantly higher micro-mechanical properties were measured for the conventional compared to the self-adhesive resin cements, although this difference was low. Within the self-adhesive resin cements group, the variation in micro-mechanical properties was high. The selection of suitable resin cements should be done by considering, besides its adhesive properties, its micro-mechanical properties and curing behaviour also.

  11. The interaction between the atmosphere and curing concrete bridge decks

    NASA Astrophysics Data System (ADS)

    Wojcik, Gary S.

    The long-term durability of concrete can be compromised by excessive concrete temperatures or temperature gradients and lack of moisture during the first few days after placement. Because the concrete binder components undergo temperature-dependent hydration reactions during this period, atmospheric and construction conditions influence the ultimate concrete quality. To understand this interaction, curing concrete bridge energy balances were estimated with meteorological techniques and calorimetry and model experiments were performed. The agreement of concrete hydration heat estimates from the energy balances, calorimetry experiments, and model simulations validates our methodology and results. In Chapter 2, we estimate from meteorological measurements and techniques the energy balances of four curing concrete bridge decks. One challenge is to determine fluxes from small surfaces (largest horizontal dimension <50 m) in a heterogeneous landscape with methods that are best suited for larger, more homogeneous areas. Estimating the concrete heat generation provides the means to successfully meet this challenge. The energy balance and calorimetry estimates of 24 h concrete heat generation agree within 20%. Between 70--85% of the concrete's heat transfer occurs at its top surface and heat transfer through steel support beams can be significant. A new parameterization for computing bulk exchange coefficients for small areas is developed. Chapter 3, we improve with calorimetry experiments a simple bimolecular heat generation expression for hydrating binder. We show that this expression, with a new parameterization accounting for retarder effects on hydration rates, simulates temperatures to within 2°C and 72 h heat generation (˜265 kJ kg-1) to within 10% of the observed. In Chapter 4, we present models developed with the field and laboratory work and show that the highest concrete temperatures occur at high initial concrete temperatures and air temperatures and

  12. ISOPAR L RELEASE FROM SALTSTONE CURED AT 55 C

    SciTech Connect

    Cozzi, A; Cora Berry, C; Michael Bronikowski, M; Russell Eibling, R; Jack Zamecnik, J

    2006-05-16

    The decontaminated salt solution waste stream from the Modular Caustic Side Solvent Extraction Unit and the Salt Waste Processing Facility is anticipated to contain entrained extraction solvent. The decontaminated salt solution is scheduled to be processed through Tank 50 into the Saltstone Production Facility. This study, among others, has been undertaken because the solvent concentration in the decontaminated salt solution may cause flammability issues within the Saltstone Disposal Facility that may need to be addressed prior to operation. Previous work at the Savannah River National Laboratory determined the release of Isopar{reg_sign} L from saltstone prepared with a simulated DSS with Isopar{reg_sign} L concentrations ranging from 50 to 200 {micro}g/g in the salt fraction and with test temperatures ranging from ambient to 95 C. The results from the curing of the saltstone showed that the Isopar{reg_sign} L release data can be treated as a percentage of initial concentration in the concentration range studied. The majority of the Isopar{reg_sign} L that was released over the test duration was released in the first few days. The release of Isopar{reg_sign} L begins immediately and the rate of release decreases over time. At higher temperatures the immediate release is larger than at lower temperatures. In this study, saltstone was prepared using a simulated decontaminated salt solution containing Isopar{reg_sign} L concentrations of 50 {micro}L/L (30 {micro}g/g) and 100 {micro}L/L (61 {micro}g/g) and cured at 55 C. The headspace of each sample was purged and the Isopar{reg_sign} L was trapped on a coconut shell carbon tube. The amount of Isopar{reg_sign} L captured was determined using NIOSH Method 1501. The percentage of Isopar{reg_sign} L released after 20 days was 1.4 - 3.7% for saltstone containing 50 {micro}L/L concentration and 2.1 - 4.3% for saltstone containing 100 {micro}L/L concentration. Given the measurement uncertainties in this work there is no

  13. The Effects of Long Term Cure on Offgassed Products of Coatings

    NASA Technical Reports Server (NTRS)

    Engle, Ginger; Whitfield, Steve

    1997-01-01

    The Environmental Chemistry and Compatability Team at The Marshall Space Flight Center conducts toxic offgassing analysis on materials and flight hardware for use in habitable environments aboard the Space Shuttle and the International Space Station. As part of Research and Development, the Toxic Offgassing Laboratory conducted a long term cure study on four polyurethane coatings which are slated for potential use on Space Station. This study demonstrates the effects of cure time and temperature on the total tox value (sum T) and the maximum usage weight for each coating. All analysis was conducted according to test procedures outlined specifically for Space Station environments. Therefore, the ratings and weight limits generated for these materials are most applicable to space environments. However, this test does give some indication of time frames for solvent removal and is therefore of interest to, the environmental community as a whole.

  14. Curing APL through PML/RARA degradation by As2O3.

    PubMed

    Lallemand-Breitenbach, Valerie; Zhu, Jun; Chen, Zhu; de Thé, Hugues

    2012-01-01

    Acute promyelocytic leukemia (APL) is a hematological malignancy driven by the PML/RARA oncogene. The prognosis for patients with APL was revolutionized by two treatments: retinoic acid (RA) and As(2)O(3) (arsenic trioxide). These were both shown a posteriori to target PML/RARA, explaining their exquisite specificity for APL. Arsenic, as a single agent, cures up to 70% of patients, whereas APL patients treated with the combination of RA and As(2)O(3) reach a stunning 90% cure rate. Recent physiopathological models highlight the key role of RA- and As(2)O(3)-triggered PML/RARA degradation, and the molecular mechanisms underlying As(2)O(3)-induced PML/RARA degradation have been recently clarified. As discussed below, arsenic binding, oxidation, sumoylation on PML nuclear bodies, and RNF4-mediated ubiquitination all contribute to the As(2)O(3)-triggered catabolism of PML/RARA.

  15. 7 CFR 29.3002 - Air-cured.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... INSPECTION Standards Official Standard Grades for Burley Tobacco (u.s. Type 31 and Foreign Type 93) § 29.3002... control excess humidity during the curing period to prevent house-burn and barn-burn in damp weather....

  16. Epoxy foams using multiple resins and curing agents

    DOEpatents

    Russick, Edward M.; Rand, Peter B.

    2000-01-01

    An epoxy foam comprising a plurality of resins, a plurality of curing agents, at least one blowing agent, at least one surfactant and optionally at least one filler and the process for making. Preferred is an epoxy foam comprising two resins of different reactivities, two curing agents, a blowing agent, a surfactant, and a filler. According to the present invention, an epoxy foam is prepared with tailorable reactivity, exotherm, and pore size by a process of admixing a plurality of resins with a plurality of curing agents, a surfactant and blowing agent, whereby a foamable mixture is formed and heating said foamable mixture at a temperature greater than the boiling temperature of the blowing agent whereby said mixture is foamed and cured.

  17. Investigation of Adhesive Bond Cure Conditions using Nonlinear Ultrasonic Methods

    NASA Technical Reports Server (NTRS)

    Berndt, Tobias P.; Green, Robert E., Jr.

    1999-01-01

    The objective of this presentation is to investigate various cure conditions of adhesive bonds using nonlinear ultrasonic methods with water coupling. Several samples were used to obtain normal incidence, oblique incidence, and wave mixing.

  18. Cure monitoring using ultrasonic guided waves in wires.

    PubMed

    Vogt, T; Lowe, M; Cawley, P

    2003-09-01

    The possibility of using ultrasonic guided waves for monitoring the cure process of epoxy resins is investigated. The two techniques presented use a wire waveguide which is partly embedded in the resin. The first technique is based on the measurement of attenuation due to leakage of bulk waves into the resin surrounding the waveguide. The second technique measures the reflection of the guided wave that occurs at the point where the waveguide enters the resin. Both the attenuation and the reflection coefficient change significantly during cure, and the numerical methods to relate these to the material properties of the curing resin are presented in this paper. The results from the modeling are experimentally verified and show good agreement. The applicability of each testing method is discussed, and typical cure-monitoring curves are presented.

  19. Cure monitoring using ultrasonic guided waves in wires

    NASA Astrophysics Data System (ADS)

    Vogt, T.; Lowe, M.; Cawley, P.

    2003-09-01

    The possibility of using ultrasonic guided waves for monitoring the cure process of epoxy resins is investigated. The two techniques presented use a wire waveguide which is partly embedded in the resin. The first technique is based on the measurement of attenuation due to leakage of bulk waves into the resin surrounding the waveguide. The second technique measures the reflection of the guided wave that occurs at the point where the waveguide enters the resin. Both the attenuation and the reflection coefficient change significantly during cure, and the numerical methods to relate these to the material properties of the curing resin are presented in this paper. The results from the modeling are experimentally verified and show good agreement. The applicability of each testing method is discussed, and typical cure-monitoring curves are presented.

  20. Drinking Peroxide as 'Natural' Cure Leads to Dangerous Blood Clots

    MedlinePlus

    ... gov/news/fullstory_163513.html Drinking Peroxide as 'Natural' Cure Leads to Dangerous Blood Clots So-called ' ... suddenly releases more than 1.5 quarts of gas into the stomach, it's not surprising that there ...

  1. Factors affecting dry-cured ham consumer acceptability.

    PubMed

    Morales, R; Guerrero, L; Aguiar, A P S; Guàrdia, M D; Gou, P

    2013-11-01

    The objectives of the present study were (1) to compare the relative importance of price, processing time, texture and intramuscular fat in purchase intention of dry-cured ham through conjoint analysis, (2) to evaluate the effect of dry-cured ham appearance on consumer expectations, and (3) to describe the consumer sensory preferences of dry-cured ham using external preference mapping. Texture and processing time influenced the consumer preferences in conjoint analysis. Red colour intensity, colour uniformity, external fat and white film presence/absence influenced consumer expectations. The consumer disliked hams with bitter and metallic flavour and with excessive saltiness and piquantness. Differences between expected and experienced acceptability were found, which indicates that the visual preference of consumers does not allow them to select a dry-cured ham that satisfies their sensory preferences of flavour and texture.

  2. Method for curing polymers using variable-frequency microwave heating

    DOEpatents

    Lauf, R.J.; Bible, D.W.; Paulauskas, F.L.

    1998-02-24

    A method for curing polymers incorporating a variable frequency microwave furnace system designed to allow modulation of the frequency of the microwaves introduced into a furnace cavity is disclosed. By varying the frequency of the microwave signal, non-uniformities within the cavity are minimized, thereby achieving a more uniform cure throughout the workpiece. A directional coupler is provided for detecting the direction of a signal and further directing the signal depending on the detected direction. A first power meter is provided for measuring the power delivered to the microwave furnace. A second power meter detects the magnitude of reflected power. The furnace cavity may be adapted to be used to cure materials defining a continuous sheet or which require compressive forces during curing. 15 figs.

  3. Method for curing polymers using variable-frequency microwave heating

    DOEpatents

    Lauf, Robert J.; Bible, Don W.; Paulauskas, Felix L.

    1998-01-01

    A method for curing polymers (11) incorporating a variable frequency microwave furnace system (10) designed to allow modulation of the frequency of the microwaves introduced into a furnace cavity (34). By varying the frequency of the microwave signal, non-uniformities within the cavity (34) are minimized, thereby achieving a more uniform cure throughout the workpiece (36). A directional coupler (24) is provided for detecting the direction of a signal and further directing the signal depending on the detected direction. A first power meter (30) is provided for measuring the power delivered to the microwave furnace (32). A second power meter (26) detects the magnitude of reflected power. The furnace cavity (34) may be adapted to be used to cure materials defining a continuous sheet or which require compressive forces during curing.

  4. Global strategies are required to cure and eliminate HBV infection.

    PubMed

    Revill, Peter; Testoni, Barbara; Locarnini, Stephen; Zoulim, Fabien

    2016-04-01

    Chronic HBV infection results in >1 million deaths per year from cirrhosis and liver cancer. No known cure for chronic HBV exists, due in part to the continued presence of transcriptionally active DNA in the nucleus that is not directly targeted by current antiviral therapies. A coordinated approach is urgently needed to advance an HBV cure worldwide, such as those established in the HIV field. We propose the establishment of an International Coalition to Eliminate Hepatitis B Virus (ICE-HBV) to facilitate the formation of international working groups on HBV virology, immunology, innovative tools and clinical trials: to promote awareness and education as well as to drive changes in government policy and ensure funds are channelled to HBV cure research and drug development. With the ICE-HBV in place, it should be possible to enable a HBV cure within the next decade.

  5. 21 CFR 177.2400 - Perfluorocarbon cured elastomers.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... (channel process of furnace combustion process) (CAS Reg. No. 1333-86-4) Not to exceed 15 parts per 100..._locations.html. (2) Thermogravimetry. Perfluorocarbon cured elastomers have a major decomposition...

  6. 21 CFR 177.2400 - Perfluorocarbon cured elastomers.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... (channel process of furnace combustion process) (CAS Reg. No. 1333-86-4) Not to exceed 15 parts per 100..._locations.html. (2) Thermogravimetry. Perfluorocarbon cured elastomers have a major decomposition...

  7. 21 CFR 177.2400 - Perfluorocarbon cured elastomers.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... (channel process of furnace combustion process) (CAS Reg. No. 1333-86-4) Not to exceed 15 parts per 100..._locations.html. (2) Thermogravimetry. Perfluorocarbon cured elastomers have a major decomposition...

  8. 21 CFR 177.2400 - Perfluorocarbon cured elastomers.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... (channel process of furnace combustion process) (CAS Reg. No. 1333-86-4) Not to exceed 15 parts per 100..._locations.html. (2) Thermogravimetry. Perfluorocarbon cured elastomers have a major decomposition...

  9. The social value of candidate HIV cures: actualism versus possibilism

    PubMed Central

    Brown, Regina; Evans, Nicholas Greig

    2017-01-01

    A sterilising or functional cure for HIV is a serious scientific challenge but presents a viable pathway to the eradication of HIV. Such an event would be extremely valuable in terms of relieving the burden of a terrible disease; however, a coordinated commitment to implement healthcare interventions, particularly in regions that bear the brunt of the HIV epidemic, is lacking. In this paper, we examine two strategies for evaluating candidate HIV cures, based on our beliefs about the likelihood of global implementation. We reject possibilist interpretations of social value that do not account for the likelihood that a plan to cure HIV will be followed through. We argue, instead, for an actualist ranking of options for action, which accounts for the likelihood that a cure will be low cost, scalable and easy to administer worldwide. PMID:27402887

  10. Room-Temperature-Cured Copolymers for Lithium Battery Gel Electrolytes

    NASA Technical Reports Server (NTRS)

    Meador, Mary Ann B.; Tigelaar, Dean M.

    2009-01-01

    Polyimide-PEO copolymers (PEO signifies polyethylene oxide) that have branched rod-coil molecular structures and that can be cured into film form at room temperature have been invented for use as gel electrolytes for lithium-ion electric-power cells. These copolymers offer an alternative to previously patented branched rod-coil polyimides that have been considered for use as polymer electrolytes and that must be cured at a temperature of 200 C. In order to obtain sufficient conductivity for lithium ions in practical applications at and below room temperature, it is necessary to imbibe such a polymer with a suitable carbonate solvent or ionic liquid, but the high-temperature cure makes it impossible to incorporate and retain such a liquid within the polymer molecular framework. By eliminating the high-temperature cure, the present invention makes it possible to incorporate the required liquid.

  11. Lay theories of etiology and "cure" for four types of paraphilia: fetishism; pedophilia; sexual sadism; and voyeurism.

    PubMed

    Furnham, A; Haraldsen, E

    1998-08-01

    The current study set out to investigate the structure, determinants, and relationship between lay theories of the etiology and efficacy of "cures" for four types of paraphilia: fetishism, pedophilia, sexual sadism, and voyeurism. One hundred and five participants completed a four-part questionnaire, which was divided into (a) demographic details, (b) perceptions of the etiology, (c) ratings of cure for each paraphilia, and (d) the Eysenck Personality Questionnaire. Previous studies of lay theories have demonstrated a clear and interpretable factor structure similar to that of explicit academic theories, as well as a clear and logical relationship between perceived etiology and cure. A similar structure was expected to emerge in this study, together with positive correlations between the various factors and personality type. A factor analysis revealed a clear and logical factor structure for etiology and cure items. Further, etiology and cure factors correlated strongly with each other but only moderately with demographic details and personality differences. These findings are discussed in relation to growing literature in the field.

  12. Cure frailty models for survival data: application to recurrences for breast cancer and to hospital readmissions for colorectal cancer.

    PubMed

    Rondeau, Virginie; Schaffner, Emmanuel; Corbière, Fabien; Gonzalez, Juan R; Mathoulin-Pélissier, Simone

    2013-06-01

    Owing to the natural evolution of a disease, several events often arise after a first treatment for the same subject. For example, patients with a primary invasive breast cancer and treated with breast conserving surgery may experience breast cancer recurrences, metastases or death. A certain proportion of subjects in the population who are not expected to experience the events of interest are considered to be 'cured' or non-susceptible. To model correlated failure time data incorporating a surviving fraction, we compare several forms of cure rate frailty models. In the first model already proposed non-susceptible patients are those who are not expected to experience the event of interest over a sufficiently long period of time. The other proposed models account for the possibility of cure after each event. We illustrate the cure frailty models with two data sets. First to analyse time-dependent prognostic factors associated with breast cancer recurrences, metastases, new primary malignancy and death. Second to analyse successive rehospitalizations of patients diagnosed with colorectal cancer. Estimates were obtained by maximization of likelihood using SAS proc NLMIXED for a piecewise constant hazards model. As opposed to the simple frailty model, the proposed methods demonstrate great potential in modelling multivariate survival data with long-term survivors ('cured' individuals).

  13. Development of a scoring system using a statistical model to predict cure status in patients with cutaneous leishmaniasis

    PubMed Central

    Khoshhali, Mehri; Hosseini, Sayed Mohsen; Nilforoushzadeh, Mohammad Ali; Jaffary, Fariba; Baghbaderani, Azadeh Zolfaghari

    2017-01-01

    Background: The present study was performed to develop a scoring system for predicting cure status in patients with cutaneous leishmaniasis (CL). Materials and Methods: This study included 199 patients with CL from Skin Diseases and Leishmaniasis Research Center (Isfahan, Iran). Data were collected as longitudinal in each visit of patients. We applied ordinal logistic generalized estimating equation regression to predict score on this correlated data. To evaluate the fitted model, split sample validation method was applied. SPSS software was used for data analysis. Results: The regression coefficients of the fitted model were used to calculate score for cure status. Based on split-sample validation method, overall correct classification rate was 82%. Conclusion: This study suggested a scoring system predict cure status in CL patients based on clinical characteristics. Using this method, score for a CL patient is easily obtained by physicians or health workers.

  14. Curing time effect on the fraction of {sup 137}Cs from cement-ion exchange resins-bentonite clay composition

    SciTech Connect

    Plecas, Ilija; Dimovic, Slavko

    2007-07-01

    To assess the safety of disposal of radioactive waste material in cement, curing conditions and time of leaching radionuclides {sup 137}Cs have been studied. Leaching tests in cement-ion exchange resins-bentonite matrix, were carried out in accordance with a method recommended by IAEA. Curing conditions and curing time prior to commencing the leaching test are critically important in leach studies since the extent of hydration of the cement materials determines how much hydration product develops and whether it is available to block the pore network, thereby reducing leaching. Incremental leaching rates R{sub n}(cm/d) of {sup 137}Cs from cement ion exchange resins-bentonite matrix after 180 days were measured. The results presented in this paper are examples of results obtained in a 20-year concrete testing project which will influence the design of the engineer trenches system for future central Serbian radioactive waste storing center. (authors)

  15. Depth of Cure of New Flowable Composite Resins

    DTIC Science & Technology

    2012-03-30

    Flowable composites were introduced to the dental community in the late 1990’s (Ikeda, 2009; Bayne, 1998). The advantage of flowable composite-based...Depth of Cure of New Flowable Composite Resins A THESIS Presented to the Faculty of The Air Force Postgraduate Dental School...SCIENCE In Oral Biology By Inaam A. Pedalino, BS, DDS Dunn Dental Clinic Lackland AFB, TX 30 March 2012 Depth of Cure of New

  16. In situ composite cure monitoring using infrared transmitting optical fibers

    NASA Technical Reports Server (NTRS)

    Young, Philip R.; Druy, Mark A.; Stevenson, W. A.; Compton, David A. C.

    1988-01-01

    The development of infrared-transmitting optical fibers as sensors for monitoring the cure of advanced composite materials is reported. Fourier transform infrared spectra are presented which were remotely sensed during the cure of a high performance polyimide resin and a graphite/polyimide matrix prepreg using an 0.1 mm O.D. x 3 m chalcogenide optical fiber. A discussion of the fiber and sensor element, absorption mechanism and potential applications is presented.

  17. Influence of curing agent on fibrosis around silicone implants.

    PubMed

    Joseph, Josna; Mohanty, Mira

    2013-01-01

    Severe capsular contracture around silicone expander breast implants leading to pain and failure is a major clinical problem. Even though earlier studies have implicated the immunogenicity of silicone, the role of physical and chemical properties of the silicone material in excessive collagen deposition and fibrosis has been less addressed. The present study investigates whether there is any correlation between the type of curing systems i.e. addition and free radical curing and the fibrosis around silicone elastomer. The experiment carried out uses commercially available silicone ventriculo-peritoneal shunt material elastomer cured by platinum and the results are compared with results obtained in a similar study carried out by the authors using commercially available silicone tissue expander material cured by peroxide. Ultra-high molecular weight poly-ethylene (UHMWPE), the standard reference for biocompatibility evaluation, was used as the control material. The materials were implanted in rat skeletal muscle for 30 and 90 days. Inflammatory cells, myofibroblasts, cytokines, and collagen deposition at the material-tissue interface were identified by haematoxylin-eosin and Masson's Trichrome stains and semi-quantitated based on immunohistochemical studies. Results indicate that even though the cellular response in the initial phase of wound healing was similar in both platinum and peroxide-cured materials, the collagen deposition in the proliferative phase was more around peroxide-cured material in comparison to the platinum-cured silicone elastomer. There is a need to look into the molecular mechanisms of this interaction and the possibility of using curing systems other than free radical peroxide in the manufacture of silicone elastomer expanders for breast prosthesis.

  18. Pulsed NMR study of the curing process of epoxy resin.

    PubMed

    Kimoto, Hiroki; Tanaka, Chikako; Yaginuma, Michiko; Shinohara, Emi; Asano, Atsushi; Kurotsu, Takuzo

    2008-07-01

    To analyze a curing process of epoxy resin in terms of molecular motion, we adapted a pulsed NMR method. Three kinds of (1)H spin-spin relaxation times (T(2L) (long), T(2S) (short) and T(2M) (intermediate)) were estimated from observed solid echo train signals as the curing process proceeded. A short T(2S) value below 20 micros suggests the existence of a motion-restricted chain, that is, cured elements of resin, and its fraction, P(S), sigmoidally increased with the curing time. On the other hand, the fraction of T(2L), P(L), decreased with the reaction time reciprocally against P(S), suggesting the disappearance of highly mobile molecules raised from pre-cured resin. The spin-lattice relaxation time, T(1), was also measured to check another aspect of molecular motion in the process. T(1) of the mixed epoxy resin and curing agent gradually increased just after mixing both of them. This corresponds to an increment of a less-mobile fraction, of which the correction time is more than 10(-6) s, and also means that the occurrence of a network structure whose mobility is strongly restricted by chemically bonded bridges between the epoxy resin and curing agent. The time courses of these parameters coincided with those of IR peaks pertinent to the curing reaction. Therefore, pulsed NMR is a useful tool to monitor the hardening process of epoxy resin in real time non-distractively in terms of the molecular motion of protons.

  19. Improving light-curing instruction in dental school.

    PubMed

    Federlin, Marianne; Price, Richard

    2013-06-01

    Delivering an inadequate amount of light to a light-cured resin will result in a resin that is inadequately cured. This study measured the radiant exposure that students delivered to a simulated restoration to determine if instruction with immediate feedback increased the amount of light they delivered. The amount of light (radiant exposure in J/cm(2)) delivered to a simulated restoration by sixty-three dental students using the same curing light for twenty seconds was recorded. The experiment was repeated after the students had been given detailed light-curing instructions together with immediate feedback using the MARCPS system. Initially, the students delivered between 1.4 and 17.5 J/cm(2) (mean±SD: 9.8±3.5 J/cm(2)). After receiving instructions and feedback on their light-curing technique, they delivered between 6.7 J/cm(2) and 17.8 J/cm(2) (mean±SD: 13.2±3.3 J/cm(2)). ANOVA and Fisher's post hoc multiple comparison tests showed that providing immediate feedback on the students' light-curing technique made a significant improvement in the radiant exposure they delivered (p<0.05). It was concluded that many dental students in this study were not using the curing light properly. After the students had received one session of additional instruction and immediate feedback using the MARC-PS, they delivered 35 percent more light energy to the same simulated restoration. Students who were closer to graduation showed a greater improvement in their light-curing technique (p=0.0091).

  20. Exploratory Development of an Ultrafast-Curing Wound Dressing

    DTIC Science & Technology

    1988-11-30

    topical antimicrobial agent should: Be poorly absorbed through skin for maximum kill potential at the applied slite * Be bactericidal at low local...our development of non -toxic, tissue compa- tible oligomers which cure under UV radiation. Curing by UV radiation is a breakthrough in medical-grade...suitable way to prevent adhesion; we concluded that poly- urethanes (being relatively tacky) could not be made non - adhe-ent. Silicone gums, on the other

  1. Feasibility study for the development of low temperature curing adhesives

    NASA Technical Reports Server (NTRS)

    Green, H. E.; Sutherland, J. D.; Sheppard, C. H.

    1974-01-01

    The feasibility of a new approach for the development of stable, easily handled, room temperature (293 K - 311 K) curing adhesives was studied and demonstrated. The work concentrated on a family of unsaturated amide/ester resins. Twelve candidate resins were synthesized and tested for completeness of cure at room temperature, adhesion to aluminum and titanium, shear strength, moisture resistance and heat stability. The three most promising candidate resins were selected and recommended for further development.

  2. Prediction of the curing time to achieve maturity of the nano-cement based concrete using the Weibull distribution model: A complementary data set.

    PubMed

    Jo, Byung Wan; Chakraborty, Sumit; Kim, Heon

    2015-09-01

    This data article provides a comparison data for nano-cement based concrete (NCC) and ordinary Portland cement based concrete (OPCC). Concrete samples (OPCC) were fabricated using ten different mix design and their characterization data is provided here. Optimization of curing time using the Weibull distribution model was done by analyzing the rate of change of compressive strength of the OPCC. Initially, the compressive strength of the OPCC samples was measured after completion of four desired curing times. Thereafter, the required curing time to achieve a particular rate of change of the compressive strength has been predicted utilizing the equation derived from the variation of the rate of change of compressive strength with the curing time, prior to the optimization of the curing time (at the 99.99% confidence level) using the Weibull distribution model. This data article complements the research article entitled "Prediction of the curing time to achieve maturity of the nano-cement based concrete using the Weibull distribution model" [1].

  3. Depth of cure of bulk-fill flowable composite resins.

    PubMed

    Pedalino, Inaam; Hartup, Grant R; Vandewalle, Kraig S

    2015-01-01

    In recent years, manufacturers have introduced flowable composite resins that reportedly can be placed in increments of 4 mm or greater. The purpose of this study was to evaluate the depth of cure of bulk-fill flowable composite resins (SureFil SDR Flow, Grandio Flow, and Venus Bulk Fill) and a conventional flowable composite resin (Revolution Formula 2). Depth of cure was measured in terms of bottom-maximum Knoop hardness number (KHN) ratios and the International Organization for Standardization (ISO) 4049 scrape technique. Shades A2 and A3 of SureFil SDR Flow, Grandio Flow, and Revolution Formula 2 were tested. Venus Bulk Fill was tested in its only available shade (universal). Specimens in thicknesses of 2, 3, 4, 5, and 6 mm were polymerized for 20 or 40 seconds, and a hardness tester was used to determine the hardness ratios for each shade at each thickness. For the scraping technique, after specimens were exposed to the curing light, unpolymerized composite resin was removed with a plastic instrument, the polymerized composite was measured, and the length was divided by 2 per ISO guidelines. According to the KHN ratios and the scrape test, Venus Bulk Fill predictably exceeded the manufacturer's claim of a 4-mm depth of cure at both 20 and 40 seconds of curing time. The overall results for depth of cure showed that Venus Bulk Fill ≥ SureFil SDR Flow ≥ Grandio Flow ≥ Revolution Formula 2.

  4. Tg and Cure of a Polycyanurate at the Nanoscale

    NASA Astrophysics Data System (ADS)

    Simon, Sindee; Li, Qingxiu

    2008-03-01

    Nanoscale constraint is known to have a significant impact on the thermal properties of materials. Although thermosetting resins have been cured in the presence of nanoparticles and nanotubes, cure of thermosetting resins under the well defined nanoscale constraints imposed by controlled pore glass (CPG) or similar matrices has not been previously documented. In this work, we investigate the isothermal curing under nanoscale constraint of a thermosetting resin, bisphenol M dicyanate ester (BMDC), which trimerizes to form a polycyanurate network material. Differential scanning calorimeter is used to monitor the evolution of the glass transition temperature (Tg) and the conversion during cure as a function of the diameter of the silanized control pore glass matrix which is used for confinement. A Tg depression is observed for both the bisphenol M dicyanate ester monomer and the polycyanurate networks; the depression is only a few degrees for the monomer, whereas a 56 K depression is observed for the ``fully-cured'' network in 11.5 nm pores. The nanoscale constraint is also found to accelerate the cure of the bisphenol M dicyanate ester, but it does not affect the normalized Tg versus conversion relationship. The appearance of a secondary Tg above the primary Tg in the smaller pores and the associated length scale are discussed.

  5. Electron Beam-Cure Polymer Matrix Composites: Processing and Properties

    NASA Technical Reports Server (NTRS)

    Wrenn, G.; Frame, B.; Jensen, B.; Nettles, A.

    2001-01-01

    Researchers from NASA and Oak Ridge National Laboratory are evaluating a series of electron beam curable composites for application in reusable launch vehicle airframe and propulsion systems. Objectives are to develop electron beam curable composites that are useful at cryogenic to elevated temperatures (-217 C to 200 C), validate key mechanical properties of these composites, and demonstrate cost-saving fabrication methods at the subcomponent level. Electron beam curing of polymer matrix composites is an enabling capability for production of aerospace structures in a non-autoclave process. Payoffs of this technology will be fabrication of composite structures at room temperature, reduced tooling cost and cure time, and improvements in component durability. This presentation covers the results of material property evaluations for electron beam-cured composites made with either unidirectional tape or woven fabric architectures. Resin systems have been evaluated for performance in ambient, cryogenic, and elevated temperature conditions. Results for electron beam composites and similar composites cured in conventional processes are reviewed for comparison. Fabrication demonstrations were also performed for electron beam-cured composite airframe and propulsion piping subcomponents. These parts have been built to validate manufacturing methods with electron beam composite materials, to evaluate electron beam curing processing parameters, and to demonstrate lightweight, low-cost tooling options.

  6. Investigations on N-nitrosopyrrolidine in dry-cured bacon.

    PubMed

    Fiddler, W; Pensabene, J W; Gates, R A; Foster, J M; Smith, W J

    1989-01-01

    Dry-cured or "country-style" bacon is a low volume specialty product typically made by small producers whose production practices vary widely. These practices include the direct application of dry-cure formulations containing varying concentrations of salt, sugar, flavoring agents, sodium nitrite, and sometimes sodium nitrate, and the use of lengthy curing and processing times. Because of the possibility of generating higher levels of N-nitrosopyrrolidine (NPYR) after frying in this product type compared with pump-cured bacon, an investigation was carried out on dry-cured bacon obtained from cooperating state or federally inspected establishments. Three different samples from each of the 16 plants were analyzed. Only one sample from each of 2 different producers exceeded the Food Safety and Inspection Service (FSIS) action level of 17 ppb NPYR, indicating that the majority of samples tested were in compliance. A significant correlation (P less than 0.01) was found between residual NaNO2 prior to frying and NPYR after frying. The elimination of added nitrate in the dry-cure formulations is recommended.

  7. The mechanism of plasmid curing in bacteria.

    PubMed

    Spengler, Gabriella; Molnár, Annamária; Schelz, Zsuzsanna; Amaral, Leonard; Sharples, Derek; Molnár, Joseph

    2006-07-01

    plasmids. The inhibition of conjugational transfer of antibiotic resistance plasmid can be exploited to reduce the spread of antibiotic resistance plasmid in the ecosystem. Inhibition of plasmid replication at various stages, as shown in the "rolling circle" model (replication, partition, conjugal transfer) may also be the theoretical basis for the elimination of bacterial virulence in the case of plasmid mediated pathogenicity and antibiotic resistance. The large number of compounds tested for antiplasmid effects provides opportunities for QSAR studies in order to find a correlation between the antiplasmid effect and the supramolecular chemistry of these plasmid curing compounds. Plasmid elimination in vitro provides a method of isolating plasmid free bacteria for biotechnology without any risk of inducing mutations.

  8. Microhardness of composite resin cured through different primary tooth thicknesses with different light intensities and curing times: In vitro study

    PubMed Central

    Mazhari, Fatemeh; Ajami, Behjatolmolok; Moazzami, Saied Mostafa; Baghaee, Bahareh; Hafez, Bahareh

    2016-01-01

    Objective: The aim of this study was to evaluate the effect of increased exposure time and light intensity on microhardness of cured composite through different thicknesses of tooth structure in primary teeth. Materials and Methods: One hundred and seventy cylindrical resin composite specimens were prepared. All specimens were divided into 17 experimental and control groups. “Light-emitting diode” light curing unit (LCU) applied directly or through 1, 2, and 3 mm thicknesses tooth slices for experimental groups. The irradiation protocols were 25 and 50 s at 650 mW/cm2 and 15 and 30 s at 1100 mW/cm2. The “quartz-tungsten-halogen” LCU (400 mW/cm2) for 40 s was used in control group. Microhardness was measured by the Vickers hardness test. Results: Indirectly cured specimens and those cured through a 1 mm thick tooth structure, an increase in intensity caused hardness drop. In the specimens cured through 2 and 3 mm thick tooth structures, increased intensity and/or exposure time did not show any appropriate changes on microhardness. Conclusion: Irradiation through a 1.0 mm thick tooth slice resulted in reduced microhardness although it was still within the clinically acceptable level. The hardness values of the specimens cured through 2 or 3 mm thick tooth slices fell below the clinically acceptable level even after doubling the exposure time and/or light intensity. PMID:27095897

  9. Changes in the temperature of a dental light-cured composite resin by different light-curing units

    NASA Astrophysics Data System (ADS)

    Rastelli, A. N. S.; Jacomassi, D. P.; Bagnato, V. S.

    2008-08-01

    The purpose of this study was to evaluate the temperature increase during the polymerization process through the use of three different light-curing units with different irradiation times. One argon laser (Innova, Coherent), one halogen (Optilight 501, Demetron), and one blue LED (LEC 1000, MM Optics) LCU with 500 mW/cm2 during 5, 10, 20, 30, 40, 50, and 60 s of irradiation times were used in this study. The composite resin used was a microhybrid Filtek Z-250 (3M/ESPE) at color A2. The samples were made in a metallic mold 2 mm in thickness and 4 mm in diameter and previously light-cured during 40 s. A thermocouple (Model 120 202 EAJ, Fenwal Electronic, Milford, MA, USA) was introduced in the composite resin to measure the temperature increase during the curing process. The highest temperature increase was recorded with a Curing Light 2500 halogen LCU (5 and 31°C after 5 and 60 s, respectively), while the lowest temperature increase was recorded for the Innova LCU based on an argon laser (2 and 11°C after 5 and 60 s, respectively). The temperature recorded for LCU based on a blue LED was 3 and 22°C after 5 and 60 s, respectively. There was a quantifiable amount of heat generated during the visible light curing of a composite resin. The amount of heat generated was influenced by the characteristics of the light-curing units used and the irradiation times.

  10. Comparison of Shear Bond Strength and Estimation of Adhesive Remnant Index between Light-cure Composite and Dual-cure Composite: An in vitro Study

    PubMed Central

    Trehan, Mridula; Sharma, Sunil

    2013-01-01

    ABSTRACT Aims and objectives: To measure and compare the shear bond strength and adhesive remnant index of light-cure composite. (Enlight, Ormco.) and dual-cure composite (Phase II dual cure, Reliance Ortho). Materials and methods: Sixty extracted human premolar teeth were divided into two groups: group I (blue): conventional light cure composite resin. (Enlight, Ormco.) and group II (green): dual cure composite resin. (Phase II dual cure, Reliance Ortho.) with 30 teeth in each group. These samples were tested on the universal testing machine to measure the shear bond strength. Results: Student t-test showed that the mean shear bond strength of the conventional light cure group (8.54 MPa - 10.42 MPa) was significantly lower than dual cure group (10.45 MPa -12.17 MPa). Conclusion: These findings indicate that the shear bond strength of dual-cure composite resin (Phase II dual cure, Reliance Ortho) is comparatively higher than conventional light-cure composite resin (Enlight, Ormco). In the majority of the samples, adhesive remnant index (ARI) scores were 4 and 5 in both the groups whereas score 1 is attained by the least number of samples in both the groups. How to cite this article: Verma G, Trehan M, Sharma S. Comparison of Shear Bond Strength and Estimation of Adhesive Remnant Index between Light-cure Composite and Dual-cure Composite: An in vitro Study. Int J Clin Pediatr Dent 2013;6(3):166-170. PMID:25206216

  11. Preliminary study of light-cured hydrogel for endodontic drug delivery vehicle

    PubMed Central

    Komabayashi, Takashi; Wadajkar, Aniket; Santimano, Sonia; Ahn, Chul; Zhu, Qiang; Opperman, Lynn A.; Bellinger, Larry L.; Yang, Jian; Nguyen, Kytai T.

    2014-01-01

    Aim Direct pulp capping is the treatment of an exposed vital pulp with a dental material to facilitate the formation of reparative dentin and maintenance of vital pulp. A bioengineered drug delivery vehicle has the potential to increase the success rate of pulp capping. The aim of this study was to develop an injectable and light curing drug delivery vehicle for endodontic treatment including direct pulp capping. Methods Polyethylene glycol-maleate-citrate (PEGMC) hydrogel was synthesized as a drug delivery vehicle that is composed of PEGMC (45% w/v), acrylic acid (AA) (5% w/v), 2,2′-Azobis(2-methylpropionamidine) dihydrochloride (AAPH) (0.1% w/v), and deionized water. The association between pre-hydrogel solution volume and visible light-curing was examined. The cytotoxicity of the hydrogel was tested using L929 cells in a cell culture system. Ca2+ release from the hydrogel was determined using calcium hydroxide as the incorporated medicine. Results The results showed that the light-curing time for hydrogel is comparable to composite resin. The hydrogel had cell toxicity similar to adhesive systems. Moreover, controlled Ca2+ release was obtained from the calcium hydroxide incorporated hydrogel. Conclusion The data suggest that hydrogel should be explored further as a promising drug delivery vehicle for vital pulp therapy and regenerative endodontics. PMID:25048311

  12. Influence of argon laser curing on resin bond strength.

    PubMed

    Hinoura, K; Miyazaki, M; Onose, H

    1993-04-01

    Light cured resin composites are usually cured with halogen lamps whose light output decreases with time and distance to the resin surface. This study compared bond strengths of resins to tooth structure cured with either an argon laser or a conventional halogen light. The enamel and dentin of bovine incisors were ground on the buccal surface with wet #600 grit SiC paper. A 4 x 2 mm mold was placed on the tooth surface and Scotchbond 2/Silux and Clearfil Photobond/Photo Clearfil A were placed into the molds and cured using a Quick Light or an argon laser for exposure times of 10, 20, and 30 seconds, and distances of 0.0, 0.5, 1.0, and 1.5 mm from the resin surface. The intensity of the Quick Light was measured as 510 mW/cm2 at 470 +/- 15 nm and the intensity of the argon laser was adjusted to 510 mW/cm2 before curing. Shear bond tests at a crosshead speed of 1.0 mm/min were performed after 24 hours of storage in water. The bond strengths obtained with the halogen lamp and the laser were not significantly different at the same exposure times and at 0.0 or 0.5 mm from the resin surface. The laser cured bond strengths did not decrease with increasing distance whereas there was a significant decrease in halogen bond strengths at distances greater than 0.5 mm for both resins. The use of the laser might provide a clinical advantage in cases where the curing light source cannot be brought into proximity to the surface of the resin.

  13. Comparison of halogen, plasma and LED curing units.

    PubMed

    Nomoto, Rie; McCabe, John F; Hirano, Susumu

    2004-01-01

    This study evaluated the characteristics of two kinds of recently developed light-curing unit; plasma arc and blue light emitting diodes (LED), in comparison with a conventional tungsten-halogen light-curing unit. The light intensity and spectral distribution of light from these light-curing units, the temperature rise of the bovine enamel surface and the depth of cure of composites exposed to each unit were investigated. The light intensity and depth of cure were determined according to ISO standards. The spectral distributions of emitted light were measured using a spectro-radiometer. The temperature increase induced by irradiation was measured by using a thermocouple. Generally, light intensities in the range 400-515 nm emitted from the plasma arc were greater than those from other types. Light in the UV-A region was emitted from some plasma arc units. The required irradiation times were six to nine seconds for the plasma arc units and 40 to 60 seconds for the LED units to create a depth of cure equal to that produced by the tungsten-halogen light with 20 seconds of irradiation. The temperature increased by increasing the irradiation time for every light-curing unit. The temperature increases were 15 degrees C to 60 degrees C for plasma arc units, around 15 degrees C for a conventional halogen unit and under 10 degrees C for LED units. Both the plasma arc and LED units required longer irradiation times than those recommended by their respective manufacturers. Clinicians should be aware of potential thermal rise and UV-A hazard when using plasma arc units.

  14. 21 CFR 170.60 - Nitrites and/or nitrates in curing premixes.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Nitrites and/or nitrates in curing premixes. 170... nitrates in curing premixes. (a) Nitrites and/or nitrates are food additives when combined in curing... nitrates, when packaged separately from flavoring and seasoning in curing premixes, may continue to be...

  15. Acrylic injectable and self-curing formulations for the local release of bisphosphonates in bone tissue.

    PubMed

    Rodríguez-Lorenzo, L M; Fernández, M; Parra, J; Vázquez, B; López-Bravo, A; Román, J San

    2007-11-01

    Two bisphosphonates (BPs), namely 1-hydroxy-2-[4-aminophenyl]ethane-1,1-diphosphonic acid (APBP) and 1-hydroxy-2-[3-indolyl]ethane-1,1-diphosphonic acid (IBP), have been synthesized and incorporated to acrylic injectable and self-curing formulations. Alendronic acid monosodium trihydrated salt (ALN) containing cement was formulated as control. These systems have potential applications in low density hard tissues affected by ailments characterized by a high osteoclastic resorption, i.e. osteoporosis and osteolysis. Values of curing parameters of APBP and IBP were acceptable to obtain pastes with enough fluency to be injected through a biopsy needle into the bone cavity. Working times ranged between 8 and 15 min and maximum temperature was around 50 degrees C. Cured systems stored for a month in synthetic body fluid had compressive strengths between 90 and 96 MPa and modulus between 1.2 and 1.3 GPa, which suggest mechanical stabilization after setting and in the short time. BPs were released in PBS at an initial rate depending on the corresponding chemical structure in the order ALN > APBP > IBP to give final concentrations in PBS of 2.21, 0.44, and 0.19 mol/mL for ALN, APBP, and IBP, respectively. Cytotoxicities of bisphosphonates were evaluated, IC(50) values being in the order APBP > ALN > IBP. Absence of cytotoxicity coming from leachables of the cured systems was observed in all cases independently of the BP. An improved cell growth and proliferation for the systems loaded with APBP and IBP compared with that loaded with ALN was observed, as assessed by measuring cell adhesion and proliferation, and total DNA content.

  16. Caul and method for bonding and curing intricate composite structures

    NASA Technical Reports Server (NTRS)

    Willden, Kurtis S. (Inventor); Goodno, Kenneth N. (Inventor)

    1993-01-01

    The invention disclosed here is a method for forming and curing an intricate structure of criss-crossing composite stringers and frames that are bonded to a skin panel. A structure constructed in accordance with the invention would be well-suited for use as a portion of an aircraft fuselage, a boat hull, or the like. The method is preferably practiced by applying uncured composite stringers to an uncured composite sheet panel. This is followed by placing cured frames crosswise over the stringers. The frames have openings at the locations where they intersect with the stringers which enables the frames to come into direct contact with the skin along most of their length. During the forming and curing process, the stringers are covered with a plurality of cauls, and the entire assembly of skin panel, stringers, frames and cauls is subjected to a vacuum bagging and curing process. The cauls serve to maintain both part shape and to control the flow of resin within the stringers as they are cured. Further, they probably eliminate the need for intermediate protective materials between the vacuum bag and the stringers.

  17. Estimation of intervention effects using recurrent event time data in the presence of event dependence and a cured fraction.

    PubMed

    Xu, Ying; Lam, K F; Cheung, Yin Bun

    2014-06-15

    Recurrent event data with a fraction of subjects having zero event are often seen in randomized clinical trials. Those with zero event may belong to a cured (or non-susceptible) fraction. Event dependence refers to the situation that a person's past event history affects his future event occurrences. In the presence of event dependence, an intervention may have an impact on the event rate in the non-cured through two pathways-a primary effect directly on the outcome event and a secondary effect mediated through event dependence. The primary effect combined with the secondary effect is the total effect. We propose a frailty mixture model and a two-step estimation procedure for the estimation of the effect of an intervention on the probability of cure and the total effect on event rate in the non-cured. A summary measure of intervention effects is derived. The performance of the proposed model is evaluated by simulation. Data on respiratory exacerbations from a randomized, placebo-controlled trial are re-analyzed for illustration.

  18. Coarse-Grained Molecular Dynamics Study of the Curing and Properties of Highly Cross-Linked Epoxy Polymers.

    PubMed

    Aramoon, Amin; Breitzman, Timothy D; Woodward, Christopher; El-Awady, Jaafar A

    2016-09-08

    In this work, a coarse-grained model is developed for highly cross-linked bisphenol A diglycidyl ether epoxy resin with diaminobutane hardener. In this model, all conformationally relevant coarse-grained degrees of freedom are accounted for by sampling over the free-energy surfaces of the atomic structures using quantum mechanical simulations. The interaction potentials between nonbonded coarse-grained particles are optimized to accurately predict the experimentally measured density and glass-transition temperature of the system. In addition, a new curing algorithm is also developed to model the creation of highly cross-linked epoxy networks. In this algorithm, to create a highly cross-linked network, the reactants are redistributed from regions with an excessive number of reactive molecules to regions with a lower number of reactants to increase the chances of cross-linking. This new algorithm also dynamically controls the rate of cross-linking at each local region to ensure uniformity of the resulting network. The curing simulation conducted using this algorithm is able to develop polymeric networks having a higher average degree of cross-linking, which is more uniform throughout the simulation cell as compared to that in the networks cured using other curing algorithms. The predicted gel point from the current curing algorithm is in the acceptable theoretical and experimental range of measured values. Also, the resulting cross-linked microstructure shows a volume shrinkage of 5%, which is close to the experimentally measured volume shrinkage of the cured epoxy. Finally, the thermal expansion coefficients of materials in the glassy and rubbery states show good agreement with the experimental values.

  19. Post-Vitrification Cure Kinetics of High Temperature Composite Resins: Implications for Characterization and Performance

    DTIC Science & Technology

    2013-05-09

    Viewgraph 3. DATES COVERED (From - To) March 2013- May 2013 4. TITLE AND SUBTITLE POST-VITRIFICATION CURE KINETICS OF HIGH TEMPERATURE COMPOSITE RESINS...transition temperature of the composite resin on the extent of cure leads to unusual cure effects such as 1) significant cure below the glass transition...that cure at high temperature can lead to design strategies for high-temperature composite resins that provide optimal performance. 15. SUBJECT TERMS

  20. Does use of flue-cured rather than blended cigarettes affect international variation in mortality from lung cancer and COPD?

    PubMed

    Lee, Peter N; Forey, Barbara A; Fry, John S; Hamling, Jan S; Hamling, John F; Sanders, Edward B; Carchman, Richard A

    2009-04-01

    We compared risk of lung cancer and chronic obstructive pulmonary disease (COPD) associated with flue-cured and blended cigarettes. Mortality and smoking data were collected for 1971-2000 by sex, age, and period for three countries with a mainly flue-cured market and four with a blended market. Epidemiological relative risk estimates for current and ex smoking were summarized. Smoking statistics and mortality were compared between flue-cured cigarette and blended cigarette countries. Unadjusted mortality rates were generally lower in blended cigarette countries early on, with the difference diminishing or reversing by the 1990s. Differences by cigarette type were rarely significant, due to variations, particularly for COPD, between countries within cigarette type. Current smoking prevalence was generally lower in blended cigarette countries in 1971-1975, with the difference reducing over time. Differences by type were never significant, with blended cigarette countries varying markedly. Ex-smoking increased over time and was lower for blended cigarette countries, generally not significantly. Consumption per smoker was somewhat lower for blended cigarette countries. Relative risk estimates for smoking, derived mainly from U.S. and UK studies, varied little by cigarette type. Conclusions based on estimated smoking-related excess mortality were similar to those based on unadjusted mortality rates. There was little indication of any difference between flue-cured and blended cigarettes on risk of lung cancer or COPD. Our approach could have detected differences of about 40% for male lung cancer, or twofold differences for females or for COPD, had they existed. Between-country differences in rates of two major diseases predominantly caused by smoking cannot materially be explained by whether the countries use flue-cured or blended cigarettes.

  1. Cure of Xenografted Human Carcinomas by BR96-Doxorubicin Immunoconjugates

    NASA Astrophysics Data System (ADS)

    Trail, P. A.; Willner, D.; Lasch, S. J.; Henderson, A. J.; Hofstead, S.; Casazza, A. M.; Firestone, R. A.; Hellstrom, I.; Hellstrom, K. E.

    1993-07-01

    Immunoconjugates (BR96-DOX) were prepared between chimeric monoclonal antibody BR96 and the anticancer drug doxorubicin. The monoclonal antibody binds an antigen related to Lewis Y that is abundantly expressed at the surface of cells from many human carcinomas; it has a high degree of tumor selectivity and is internalized after binding. BR96-DOX induced complete regressions and cures of xenografted human lung, breast, and colon carcinomas growing subcutaneously in athymic mice and cured 70 percent of mice bearing extensive metastases of a human lung carcinoma. Also, BR96-DOX cured 94 percent of athymic rats with subcutaneous human lung carcinoma, even though the rats, like humans and in contrast to mice, expressed the BR96 target antigen in normal tissues.

  2. The application of carbon fiber resistancein monitoring of curing

    NASA Astrophysics Data System (ADS)

    Sun, X. Y.; Zhang, B. M.; Zong, Yang

    2009-07-01

    Thermal residual stress in resin matrix composite due to the different coefficient of thermal expansion (CTE). The CTE of carbon fiber is lower than resin matrix. Based on mechanics, rising temperature will induce tensile stress, cooling down will induce compress in fiber. There exists expanding and shrinkage during curing process of epoxy. In single fiber composite system, they play different roles, present with tensile and compress stress on fiber. This paper deals with the relationship of the carbon fiber resistance with strain and temperature. The effect of expanding and shrinkage on residual stress is got by the fiber resistant measurement. Resistance variety curve of the experiment shows the chemical process during resin solidification. The shear stress between fiber and matrix existing during temperature load can also measured by the same method. The carbon fiber's resistant can be used as sensor to monitor and control the curing process. This is a simple and effective method to research the curing process.

  3. Modelling geographically referenced survival data with a cure fraction.

    PubMed

    Cooner, Freda; Banerjee, Sudipto; McBean, A Marshall

    2006-08-01

    The emergence of geographical information systems and related softwares nowadays enables medical databases to incorporate the geographical information on patients, allowing studies in spatial associations. Public health administrators and researchers are often interested in detecting variation in survival patterns by region or county in order to understand the possible factors that contribute towards such spatial discrepancies. These issues have led statisticians to develop survival models that account for spatial clustering and variation. Additionally, with rapid developments in medical and health sciences, researchers increasingly encounter data sets where a substantial portion of patients are cured. Models accounting for cure in the population assist in the prognosis of potentially terminal diseases. This article proposes a Bayesian modelling framework that models spatial associations for areally referenced survival data using a general class of cure models proposed by Cooner et al. The special models we outline are alternatives to the traditional proportional hazards models and can be fitted using standard Bayesian software such as WinBUGS.

  4. ProCure21+ should speed scheme starts.

    PubMed

    Baillie, Jonathan

    2010-11-01

    This October saw the launch of the new ProCure21+ National Framework under which, the Department of Health (DH) team behind the new scheme claims, the NHS can potentially save a further pound 200 million of public money on top of the substantial sums saved under predecessor, ProCure21, via faster, more streamlined procurement, design, planning, and construction, of publicly-funded healthcare schemes. HEJ editor Jonathan Baillie discussed, with the DH's senior responsible officer (SRO) and P21+ team leader Peter Sellars, the background to the new Framework's introduction, the success of its forerunner, and the additional benefits that ProCure21 + (which is backed by organisations incuding HM Treasury, the National Audit Office, and the Office of Government Commerce) should bring to the entire healthcare building supply chain.

  5. Lower temperature curing thermoset polyimides utilizing a substituted norbornene endcap

    NASA Technical Reports Server (NTRS)

    Waters, John F.; Sukenik, Chaim N.; Kennedy, Vance O.; Livneh, Mordechai; Youngs, Wiley J.; Sutter, James K.; Meador, Mary A. B.; Burke, Luke A.; Ahn, Myong K.

    1992-01-01

    Methoxycarbonyl bridgehead substituted nadic diacid monomethyl ester, when used as an endcapping monomer, lowered the cure temperature of thermoset PMR polyimides without seriously affecting other desirable properties, such as glass transition temperature and thermal oxidative stability. The C-13 CP/MAS NMR of model compounds was used to follow the cure of resin systems using both the unmodified nadic endcap and the methoxycarbonyl-substituted endcap. Rheological analysis and differential scanning calorimetry DSC also provided evidence for the lower curing nature of the substituted endcap. Two regioisomers of the bridgehead-substituted endcap were isolated, and their chemical structures were elucidated by X-ray crystallography. The model compound and molecular modeling studies conducted ruled out the possibility of regioisomeric imide formation in the substituted endcaps.

  6. Curing of an R Factor from Escherichia coli by Trimethoprim

    PubMed Central

    Pinney, R. J.; Smith, J. T.

    1973-01-01

    R factor 1818, which we have shown previously to be eliminated by thymine starvation, was cured from three strains of Escherichia coli K-12 by overnight exposure to trimethoprim. Elimination was abolished in the presence of added thymine or thymidine, which suggests that curing is the result of the induction of thymineless conditions by trimethoprim. Starvation of the required amino acids proline and histidine had little effect on elimination, whereas methionine deprivation enhanced it. R factor curing was abolished by the presence of chloramphenicol, and it is concluded that protein synthesis is required for elimination to occur. It is suggested that elimination may result from the activity of a nuclease which is synthesized or induced during both direct thymine starvation and by trimethoprim treatment. PMID:4597737

  7. Remote cure monitoring of polymeric resins by laser Raman spectroscopy

    SciTech Connect

    Hong, K.C.; Vess, T.M.; Lyon, R.E.; Myrick, M.L.

    1993-05-01

    The validity of using Raman spectroscopy to monitor the cure chemistries of amine-cured epoxy is demonstrated by correlating NIR absorbance measurements with Raman measurements for a concentration series of bisphenol-A diglycidylether in its own reaction product with diethylamine. The intensity of a normalized Raman peak at 1240 cm{sup {minus}l}, assigned to the epoxide functionality, was found to be linearly related to the concentration of epoxide groups in the resin mixtures. Also, it is shown that the Ciba-Geigy Matrimid 5292 system can be monitored by ex-situ FT-Raman spectroscopy by observing changes in the carbonyl stretching (1773 cm{sup {minus}1}) or the C=C stretching of maleimide (1587 cm{sup {minus}1}) during the cure reaction.

  8. Test of cure for gonorrhea in teenagers. Who complies and does continuity of care help?

    PubMed

    Chacko, M R; Wells, R D; Phillips, S A

    1987-05-01

    This study evaluates factors influencing test of cure (TOC) compliance for gonorrhea in teenagers attending a public sexually transmitted disease (STD) clinic. The efficacy of providing continuity of care to improve the TOC rate is also evaluated. Overall, females complied better (54%) than males (33%), and younger males better than older males (greater than 16 years of age). Of patients with a prior history of gonorrhea, the TOC rates were significantly higher for those who had previously kept their TOC appointment. Continuity of care did not improve the TOC rate, but initial contact with a clinician appeared to influence the return rate of female adolescents. Male adolescents will apparently require a different intervention strategy to improve their appointment keeping.

  9. Hardness Evaluation of Composite Resins Cured with QTH and LED

    PubMed Central

    Esmaeili, Behnaz; Safarcherati, Hengameh; Vaezi, Assila

    2014-01-01

    Background and aims. Today light cured composites are widely used. Physical and mechanical properties of composites are related to the degree of conversion. Light curing unit (LCU) is an important factor for composite polymerization. Aim of this study is evaluation of composite resins hardness using halogen and LED light curing units. Materials and methods. In this study, 30 samples of Filtek Z250 and C-Fill composite resins were provided. Samples were light cured with Ultralume2, Valo and Astralis7. Vickers hardness number (VHN) was measured in 0, 1, 2 mm depth. Statistical analysis used: Data were analysed by SPSS software and compared with each other by T-test, one-way and two-way ANOVA and Post-hoc Tukey test. Results. In Filtek Z250, at top surface, VHN of Ultralume2 was higher than VHN of Valo (P = 0.02) and Astralis7 (P =0.04), but in depth of 1, 2 mm, VHN of Ultralume2 and Astralis7 were almost the same and both LCUs were more than Valo which the difference between Ultralume2 and Valo was significant in depth of 1mm (0.05) and 2mm (0.02). In C-Fill composite, at top surface, Astralis7 showed higher VHN, but in depth of 2 mm, performance of all devices were rather simi-lar. Conclusion. In Z250, which contains camphorquinone initiator, light cure LED Ultra-lume2 with narrow wavelength showed higher hardness number than Valo. In C-fill, in top surface, Astralis7 with more exposure time, resulted higher VHN. But In depth of 2 mm, various light curing devices had rather similar hardness number. PMID:25024838

  10. In-situ Frequency Dependent Dielectric Sensing of Cure

    NASA Technical Reports Server (NTRS)

    Kranbuehl, David E.

    1996-01-01

    With the expanding use of polymeric materials as composite matrices, adhesives, coatings and films, the need to develop low cost, automated fabrication processes to produce consistently high quality parts is critical. Essential to the development of reliable, automated, intelligent processing is the ability to continuously monitor the changing state of the polymeric resin in-situ in the fabrication tool. This final report discusses work done on developing dielectric sensing to monitor polymeric material cure and which provides a fundamental understanding of the underlying science for the use of frequency dependent dielectri sensors to monitor the cure process.

  11. Optimization of the curing process of a sandwich panel

    NASA Astrophysics Data System (ADS)

    Phyo Maung, Pyi; Tatarnikov, O.; Malysheva, G.

    2016-10-01

    This study presented finite element modelling and experimental measurements of temperatures during the autoclave curing of the T-50 aircraft wing sandwich panel. This panel consists of upper and lower carbon fibre based laminates and an aluminium foil honeycomb. The finite element modelling was performed using the Femap-Nastran product. During processing, the temperature at various points on the surface of the panel was measured using the thermocouples. The finite element method simulated the thermal conditions and determined the temperatures in the different parts of the panel for a full cycle of the curing process. A comparison of the calculated and experimental data shows that their difference does not exceed 6%.

  12. Effects of Temperature and Humidity on Wilethane 44 Cure

    SciTech Connect

    John C. Weigle

    2006-10-01

    Wilethane 44 is a polyurethane adhesive developed by the Materials Team within ESA-MEE at Los Alamos National Laboratory as a replacement for Hexcel Corporation Urethane 7200. Urethane 7200 is used in numerous weapon systems, but it was withdrawn from the market in 1989. The weapons complex requires a replacement material for use in the W76-1 LEP and the W88, as well as for assembly of JTAs for other warheads. All polyurethane systems are susceptible to moisture reacting with unreacted isocyanate groups. This side reaction competes with the curing reaction and results in CO{sub 2} formation. Therefore, a polyurethane adhesive can exhibit foaming if appropriate environmental controls are not in place while it cures. A designed experiment has been conducted at TA-16-304 to determine the effects of ambient conditions on the properties of cured Wilethane 44. Temperature was varied from 15 C to 30 C and relative humidity from 15% to 40%. The density, hardness at 24 hours, and butt tensile strength on aluminum substrates were measured and fitted to quadratic equations over the experimental space. Additionally, the loss and storage moduli during cure were monitored as a function of cure temperature. These experiments provide a stronger basis for establishing appropriate environmental conditions and cure times when using Wilethane 44. The current guidelines are a working time of 90 minutes, a cure time of 18 hours, and a relative humidity of less than 25%, regardless of ambient temperature. Viscosity measurements revealed that the working time is a strong function of temperature and can be as long as 130 minutes at 15 C or as short as 90 minutes at 30 C. The experiments also showed that the gel time is much longer than originally thought, as long as 13 hours at 15 C. Consequently, it may be necessary to extend the required cure time at temperatures below 20 C. Allowable humidity varies as a function of temperature from 34% at 15 C to 15% at 30 C.

  13. Effectiveness of resin composite polymerization when cured at different depths and with different curing lights.

    PubMed

    Voltarelli, Fernanda Regina; Dos Santos-Daroz, Claudia Batitucci; Alves, Marcelo Correa; Peris, Alessandra Rezende; Marchi, Giselle Maria

    2009-01-01

    This study evaluated how photocuring devices affected the microhardness of composite resin cylinders. For this study, 120 specimens of composite were fabricated and allocated randomly into 12 groups (n = 10), according to the light source (quartz-tungsten-halogen (QTH), LED, argon laser, plasma arc) and the height of the specimen (2.0, 4.0, or 6.0 mm). Twenty-four hours after the specimens were fabricated, the Knoop microhardness test was performed on bottom and top surfaces. Statistical analysis showed significant interaction among light sources, between light sources and specimen heights, and between the surfaces. Compared to the QTH specimens, the argon laser and plasma arc specimens showed reduced polymerization on the top surface, while the plasma arc specimens showed reduced polymerization on the bottom surface. The 4.0 mm samples demonstrated higher Knoop microhardness than the 2.0 mm and 6.0 mm samples, especially when argon laser and plasma arc curing lights were used. The microhardness was always higher on the top surface than on the bottom surface. No photocuring unit was able to properly polymerize the bottom surface as completely as the top surface.

  14. Effects of feeding high protein or conventional canola meal on dry cured and conventionally cured bacon.

    PubMed

    Little, K L; Bohrer, B M; Stein, H H; Boler, D D

    2015-05-01

    Objectives were to compare belly, bacon processing, bacon slice, and sensory characteristics from pigs fed high protein canola meal (CM-HP) or conventional canola meal (CM-CV). Soybean meal was replaced with 0 (control), 33, 66, or 100% of both types of canola meal. Left side bellies from 70 carcasses were randomly assigned to conventional or dry cure treatment and matching right side bellies were assigned the opposite treatment. Secondary objectives were to test the existence of bilateral symmetry on fresh belly characteristics and fatty acid profiles of right and left side bellies originating from the same carcass. Bellies from pigs fed CM-HP were slightly lighter and thinner than bellies from pigs fed CM-CV, yet bacon processing, bacon slice, and sensory characteristics were unaffected by dietary treatment and did not differ from the control. Furthermore, testing the existence of bilateral symmetry on fresh belly characteristics revealed that bellies originating from the right side of the carcasses were slightly (P≤0.05) wider, thicker, heavier and firmer than bellies from the left side of the carcass.

  15. Muscle individual phospholipid classes throughout the processing of dry-cured ham: influence of pre-cure freezing.

    PubMed

    Pérez-Palacios, Trinidad; Ruiz, Jorge; Dewettinck, Koen; Le, Thien Trung; Antequera, Teresa

    2010-03-01

    This paper aims to study the profile of phospholipid (PL) classes of Iberian ham throughout its processing and the changes it underwent due to the influence of the pre-cure freezing treatment. The general profile of each PL class did not vary during the ripening stage. Phosphatidylcholine (PC) showed the highest proportion, followed by phosphatidyletanolamine (PE) and phosphatidylserine (PS) and phosphatidylinositol (PI) being the minor PL. The four PL classes were highly hydrolysed during the salting stage and their degradation continued during the rest of the processing. Pre-cure freezing of Iberian ham influenced the levels of the four PL classes at the initial stage, all of them being higher in refrigerated (R) than in pre-cure frozen (F) hams. Moreover, the pattern of hydrolysis was not the same in these two groups.

  16. Ultrasonic characterization of changes in viscoelastic properties of epoxy during cure

    NASA Technical Reports Server (NTRS)

    Winfree, W. P.; Parker, F. R.

    1985-01-01

    A technique for using the longitudinal velocity (LV) of an ultrasonic wave to monitor the extent of cross linking (CL) during the cure of thermosetting resins is described. The method was developed by monitoring the rate of change in LV during the cure of a bisphenol-A epoxy resin with an amine adduct. The experiment included variations in the temperature and stoichiometry in order to express the rate of change in terms of the reaction kinetics. The pulse-echo method was used with a single transducer operating at 20 MHz. Numerical models were defined to account for the acoustic response of a single layer, the attenuation and the reflection coefficient. A linear relationship was observed between the inverse of the temperature and the log of the rate of change in the velocity, supporting the theory that the velocity could be used to monitor the extent of the cross-linking reaction. An activation energy of 11.9 kcal/mole was calculated for the mixture being investigated.

  17. Heat transfer modelling of the saltstone pouring and curing process. Task Number: 93-016-0

    SciTech Connect

    Shadday, M.A. Jr.

    1993-11-01

    A byproduct of the in tank precipitation, ITP, process will be 25 million gallons of low-level salt solution. This salt solution will be mixed with cement and a flyash/slag mixture and solidified in surface vaults in the Z-area Saltstone Facility. The curing process of saltstone involves exothermic reactions, and there is a maximum temperature limit of 90{degree}C for the curing saltstone. If this temperature limit is exceeded, the physical properties of the saltstone can be degraded. A heat transfer model of the saltstone pouring and curing process has been developed that predicts transient temperature distributions in the curing saltstone. The purpose of this model is to predict peak temperatures as functions of the several independent variables in this process: pour temperature, the pour schedule, and seasonal variations in the ambient temperature. The peak temperature of the saltstone is very sensitive to the internal heat generation that accompanies the curing process. Most of the energy is released over a short period of several hours, and the balance is released slowly over a period of time that can be in excess of a month. This long term low level internal heat generation is difficult to measure in laboratory calorimetry tests, and it can significantly influence the peak temperature in the saltstone. Due to the low thermal conductivity of the saltstone, the central region of the poured saltstone will essentially heat up adiabatically. The time dependence of the internal heat generation rate was determined from an analysis of the 1991 pilot pour test. With a pour schedule of eight hours a day and five days a week in the summer, the model predicts that the saltstone will have a peak temperature of 98 C with a pour temperature of 45 C, and a peak temperature of 88 C with a pour temperature of 30 C. With a pour schedule of three days a week, the peak temperature will be 88{degree}C with a pour temperature of 45 C, and 80 C with a pour temperature of 30 C.

  18. Solidification of coatings: Theory and modeling of drying, curing and microstructure growth

    NASA Astrophysics Data System (ADS)

    Dabral, Mahendra

    1999-10-01

    This thesis explores the crucial link between processing and microstructure formation in multicomponent polymer-solvent based solution coatings that undergo solidification by a combination of drying, curing, and accompanying phase transformations. The drying process is modeled as one-dimensional coupled heat and mass transfer in a multicomponent system. Solution thermodynamics is described with Flory-Huggins theory; solvent diffusion, with multicomponent Fickian diffusion theory, which relates ternary diffusion coefficients to solvent self-diffusion coefficients and solution thermodynamics. Analysis of the model yields families of drying process paths, and time courses of compositions at successive depths into the coating. The trajectories of these paths and speed along them depend on the volatilities and diffusivities of the volatile components, and on the external drying conditions, namely gas flow rate, temperature and partial pressures of solvents in the gas phase. Porous polymeric coatings prepared by drying-induced phase separation illustrate the link between the external drying conditions and the final microstructure. Coatings dried in room air---slow natural convection and low gas phase mass transfer---give rise to a graded porous structure consisting of a dense skin atop a porous substructure. Computed process paths show that the near-surface region can vitrify rapidly. In contrast, the bulk of the solution coating undergoes phase separation by spinodal decomposition followed by coarsening. Coatings of the same solution when dried by impinging air-rapid forced convection-end up dense. All of the process paths followed by the drying coating evade the two-phase region and vitrify rapidly. Another example is drying and curing of a polyamic acid solution coated to produce polyimide film. After the coated layer is gelled, stripped and further dried and cured, the two sides---air side and substrate side, as coated or cast---differ in adhesion performance. This

  19. Effects of cement-curing mode and light-curing unit on the bond durability of ceramic cemented to dentin.

    PubMed

    Passos, Sheila Pestana; Souza, Rodrigo Othávio Assunção; Michida, Silvia Masae Araújo; Zamboni, Sandra Costa; Oliveira, Simone Helena Gonçalves de

    2013-01-01

    The aim of this study was to evaluate the effects of different light-curing units and resin cement curing types on the bond durability of a feldspathic ceramic bonded to dentin. The crowns of 40 human molars were sectioned, exposing the dentin. Forty ceramic blocks of VITA VM7 were produced according to the manufacturer's recommendations. The ceramic surface was etched with 10% hydrofluoric acid / 60s and silanized. The dentin was treated with 37% phosphoric acid / 15s, and the adhesive was applied. The ceramic blocks were divided and cemented to dentin according to resin cement / RC curing type (dual- and photo-cured), light-curing unit (halogen light / QTH and LED), and storage conditions (dry and storage / 150 days + 12,000 cycles / thermocycling). All blocks were stored in distilled water (37°C / 24h) and sectioned (n = 10): G1 - QTH + RC Photo, G2 - QTH + RC Dual, G3 - LED + RC Photo, G4 - LED + RC Dual. Groups G5, G6, G7, and G8 were obtained exactly as G1 through G4, respectively, and then stored and thermocycled. Microtensile bond strength tests were performed (EMIC), and data were statistically analyzed by ANOVA and Tukey's test (5%). The bond strength values (MPa) were: G1 - 12.95 (6.40)ab; G2 - 12.02 (4.59)ab; G3 - 13.09 (5.62)ab; G4 - 15.96 (6.32)a; G5 - 6.22 (5.90)c; G6 - 9.48 (5.99)bc; G7 - 12.78 (11.30)ab; and G8 - 8.34 (5.98)bc. The same superscript letters indicate no significant differences. Different light-curing units affected the bond strength between ceramic cemented to dentin when the photo-cured cement was used, and only after aging (LED > QTH). There was no difference between the effects of dual- and photo-cured resin-luting agents on the microtensile bond strength of the cement used in this study.

  20. Experimental Study on Effective Cure of "Tsumari" Phenomenon.

    ERIC Educational Resources Information Center

    Mito, Hiromichi

    1999-01-01

    Examines an effective method of curing tsumari, a phenomenon whereby the first note in a sequence of two eighth-notes is performed shorter than the second note. Considers two possible causes: (1) insufficient motor skill control and (2) a lack of steady beat perception. Reveals a reduction in tsumari after procedural instruction. (CMK)

  1. Recidivism and Self-Cure of Smoking and Obesity

    ERIC Educational Resources Information Center

    Schacter, Stanley

    1982-01-01

    Data indicate that addictive-appetitive disorders such as obesity, opiate use, and cigarette smoking are not (as most professionals believe) markedly resistant to long-term modification. Studies of nontherapeutic populations indicate that long-term self-cures of smoking, obesity, and drug use are relatively common events. (Author/GC)

  2. Finite-element analysis of an epoxy-curing process

    SciTech Connect

    Gartling, D K; Hickox, C E; Nunziato, J W

    1983-01-01

    A finite element numerical procedure is used to study the curing of an epoxy compound. The problem involves the gelation of an incompressible liquid due to an exothermic chemical reaction. Nonuniform temperature fields produce buoyancy-driven fluid motions that interact with the solidifying material. The numerical simulations provide temperature histories and the progression of the gel front that are compared with experimental data.

  3. Antimony to Cure Visceral Leishmaniasis Unresponsive to Liposomal Amphotericin B.

    PubMed

    Morizot, Gloria; Jouffroy, Romain; Faye, Albert; Chabert, Paul; Belhouari, Katia; Calin, Ruxandra; Charlier, Caroline; Miailhes, Patrick; Siriez, Jean-Yves; Mouri, Oussama; Yera, Hélène; Gilquin, Jacques; Tubiana, Roland; Lanternier, Fanny; Mamzer, Marie-France; Legendre, Christophe; Peyramond, Dominique; Caumes, Eric; Lortholary, Olivier; Buffet, Pierre

    2016-01-01

    We report on 4 patients (1 immunocompetent, 3 immunosuppressed) in whom visceral leishmaniasis had become unresponsive to (or had relapsed after) treatment with appropriate doses of liposomal amphotericin B. Under close follow-up, full courses of pentavalent antimony were administered without life-threatening adverse events and resulted in rapid and sustained clinical and parasitological cure.

  4. Electron beam curing of epoxy resins by cationic polymerization

    SciTech Connect

    Janke, C.J.; Dorsey, G.F.; Havens, S.J.; Lopata, V.J.

    1995-10-01

    Preliminary investigations have determined that conventional epoxy resins can be cured at selectable temperatures with high glass transition temperatures (essentially the same as with thermal curing), while still exhibiting equivalent or comparable mechanical properties. A cationic photoinitiator at a concentration of 1--3 parts per hundred of the epoxy resin is required for this process. Gamma cell screening of cationic photoinitiators with bisphenol A, bisphenol F, and cycloaliphatic epoxies demonstrated that diaryliodonium salts of weakly nucleophilic anions such as hexafluoroantimonate are most effective. Diaryliodonium salts were also found to be most effective initiators for the cationic polymerization of epoxy resins when a high energy/power electron beam accelerator was used as the source of ionizing radiation. For example Dow Tactix 123 (bisphenol A epoxy) containing 3 phr (4-octyloxyphenyl)phenyliodonium hexafluoroantimonate was irradiated at a total dosage of 100 kGy. Glass transition temperature (tan delta) of the cured material as determined by dynamic mechanical analysis was 182 C as compared to 165 C thermally cured material.

  5. Cure Characteristics of Tricyanate Ester High-Temperature Composite Resins

    DTIC Science & Technology

    2011-05-24

    Resins 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Andrew J Guenthner , Kevin R. Lamison, Matthew C. Davis and Lee R. Cambrea, 5d...degrees of freedom for more readily obtaining full cure Guenthner , A. J.; Davis, M. C.; Lamison, K. R.; Yandek, G. R.; Cambrea, L. R.; Groshens, T. J

  6. 7 CFR 30.13 - Air-cure.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Air-cure. 30.13 Section 30.13 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... AND STANDARDS Classification of Leaf Tobacco Covering Classes, Types and Groups of Grades § 30.13...

  7. 7 CFR 30.13 - Air-cure.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Air-cure. 30.13 Section 30.13 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... AND STANDARDS Classification of Leaf Tobacco Covering Classes, Types and Groups of Grades § 30.13...

  8. Religious practices in South India to cure diseases.

    PubMed

    Alam, M M; Rama Rao, B

    1998-01-01

    There is belief in South Indian villages that epidemics are due to evil spirits surrounding the villages. The propitiating of Gods and Goddesses to get rid of diseases in these villages are discussed. The Christian and Muslin traditions to cure the diseases by practising religion are also discussed.

  9. An insight of traditional plasmid curing in Vibrio species.

    PubMed

    Letchumanan, Vengadesh; Chan, Kok-Gan; Lee, Learn-Han

    2015-01-01

    As the causative agent of foodborne related illness, Vibrio species causes a huge impact on the public health and management. Vibrio species is often associated with seafood as the latter plays a role as a vehicle to transmit bacterial infections. Hence, antibiotics are used not to promote growth but rather to prevent and treat bacterial infections. The extensive use of antibiotics in the aquaculture industry and environment has led to the emerging of antibiotic resistant strains. This phenomenon has triggered an alarming public health concern due to the increase number of pathogenic Vibrio strains that are resistant to clinically used antibiotics and is found in the environment. Antibiotic resistance and the genes location in the strains can be detected through plasmid curing assay. The results derived from plasmid curing assay is fast, cost effective, sufficient in providing insights, and influence the antibiotic management policies in the aquaculture industry. This presentation aims in discussing and providing insights on various curing agents in Vibrio species. To our best of knowledge, this is a first review written discussing on plasmid curing in Vibrio species.

  10. Utopic ideas of cure and joint exploration in psychoanalytic supervision.

    PubMed

    Werbart, Andrzej

    2007-12-01

    The idea of the decisive and complete cure is deeply rooted in our unconscious and in the sacral roots of symbolic healing. Double sets of private theories of cure can frequently be found among patients in psychoanalysis and their analysts. The utopian cure involves a profound transformation of the personality by way of deep regression. The idea of an attainable and more limited cure includes new ways of managing old problems. The actual ongoing treatment is then seen as the 'next-best solution'. The utopian fantasy of creating 'the new person' by means of 'proper' psychoanalysis or analytic training has far-reaching consequences for psychoanalytic education and supervision. Our awareness of the inevitable temptation in the 'utopian state of mind' can help us to trace and focus on utopic elements in the supervisory process. Exploration of utopic ideas of all the three parties involved can itself be a fruitful and stimulating way of working in supervision. An important aim of psychoanalytic supervision is to promote a distinct state of mind that can counterbalance utopic ideas and counteract the phenomenon of a 'false analytic self'.

  11. [Non continent urinary transcutaneous derivation to cure recurrent vesicostomy prolapse].

    PubMed

    Stainier, A; Di Gregorio, M; Tombal, B

    2009-12-01

    Vesicostomy prolapse is a frequent complication of an unusual surgical technique in adult patients. We have described a surgical technique to repair a vesicostomy prolapse using subcutaneous tubulisation of thick cutaneous flap taken off the abdominal wall. This technique could help surgeons to cure prolapse of vesicostomy in case of impossible intraperitoneal approach.

  12. Student Actor Ailments: Ten Ills and How To Cure Them.

    ERIC Educational Resources Information Center

    Bishop, Barbara Long

    2000-01-01

    Lists the top ten acting ailments often encountered in student actors, and offers advice to cure these ailments: the split personality, the beauty queen and the leading man, the comedian, the director in training, the moody one, the character-clueless, the loner, the mimic, the stage-frightened, and the opening night artist. (SR)

  13. Radical-cured block copolymer-modified thermosets

    SciTech Connect

    Redline, Erica M.; Francis, Lorraine F.; Bates, Frank S.

    2013-01-10

    Poly(ethylene-alt-propylene)-b-poly(ethylene oxide) (PEP-PEO) diblock copolymers were synthesized and added at 4 wt % to 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy)phenyl]propane (BisGMA), a monomer that cures using free radical chemistry. In separate experiments, poly(ethylene glycol) dimethacrylate (PEGDMA) was combined as a secondary monomer with BisGMA and the monomers were loaded with 4 wt % PEP-PEO. The diblock copolymers self-assembled into well-dispersed spherical micelles with PEP cores and PEO coronas. No appreciable change in the final extent of cure of the thermosets was caused by the addition of diblock copolymer, except in the case of BisGMA, where the addition of the block copolymer increased extent of cure by 12%. Furthermore, the extent of cure was increased by 29% and 37% with the addition of 25 and 50 wt % PEGDMA, respectively. Elastic modulus and fracture resistance were also determined, and the values indicate that the addition of block copolymers does not significantly toughen the thermoset materials. This finding is surprising when compared with the large increase in fracture resistance seen in block copolymer-modified epoxies, and an explanation is proposed.

  14. 21 CFR 177.2400 - Perfluorocarbon cured elastomers.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... to such limitations as are provided: Substances Limitations Carbon black (channel process of furnace combustion process) (CAS Reg. No. 1333-86-4) Not to exceed 15 parts per 100 parts of the terpolymer...) Thermogravimetry. Perfluorocarbon cured elastomers have a major decomposition peak occurring at 490° ±15 °C (914...

  15. 1. FACTORY BUILDING VIEWED FROM THE EAST, CURING AND STORAGE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. FACTORY BUILDING VIEWED FROM THE EAST, CURING AND STORAGE WING TO THE LEFT, BOILING HOUSE IN THE CENTER, GRINDING PLATFORM TO THE FAR RIGHT, ST. THOMAS ISLAND VISIBLE IN BACKGROUND - Caneel Bay Plantation, Sugar Factory, Cruz Bay, St. John, VI

  16. Clinical Applications of Genome Editing to HIV Cure.

    PubMed

    Wang, Cathy X; Cannon, Paula M

    2016-12-01

    Despite significant advances in HIV drug treatment regimens, which grant near-normal life expectancies to infected individuals who have good virological control, HIV infection itself remains incurable. In recent years, novel gene- and cell-based therapies have gained increasing attention due to their potential to provide a functional or even sterilizing cure for HIV infection with a one-shot treatment. A functional cure would keep the infection in check and prevent progression to AIDS, while a sterilizing cure would eradicate all HIV viruses from the patient. Genome editing is the most precise form of gene therapy, able to achieve permanent genetic disruption, modification, or insertion at a predesignated genetic locus. The most well-studied candidate for anti-HIV genome editing is CCR5, an essential coreceptor for the majority of HIV strains, and the lack of which confers HIV resistance in naturally occurring homozygous individuals. Genetic disruption of CCR5 to treat HIV has undergone clinical testing, with seven completed or ongoing trials in T cells and hematopoietic stem and progenitor cells, and has shown promising safety and potential efficacy profiles. Here we summarize clinical findings of CCR5 editing for HIV therapy, as well as other genome editing-based approaches under pre-clinical development. The anticipated development of more sophisticated genome editing technologies should continue to benefit HIV cure efforts.

  17. Preparation and cured properties of novel cycloaliphatic epoxy resins

    SciTech Connect

    Tokizawa, Makoto; Okada, Hiroyoshi; Wakabayashi, Nobukatsu; Kimura, Tomiaki . Research Center)

    1993-10-20

    Preparation and characterization of novel cycloaliphatic epoxy resins, which are derived from octadienyl compounds, were studied. From a model peracetic acid epoxidation reaction using 2,7-octadienyl acetate-1, the structure of the liquid resins is estimated to be mainly terminal epoxides and some amount of inner epoxide depending on the epoxide content. The epoxy resins offer lower toxicity and lower vapor pressure. The reactivity of the resin with acid anhydrides is moderate but faster than that of traditional cyclohexane epoxide-type resins and slower than that of the glycidyl ester-type resins. This reactivity was also examined using model compounds. The heat deflection temperature of the hexahydro-phthalic anhydride-cured resins is shown to be directly proportional to the number of epoxy groups in the molecules. The flexural strength of the cured resins is nearly equivalent to that of the commercial resins, although the flexural elongation of the resins is larger than that of the rigid cyclohexane epoxide-type resins. The thermal stability of the cured resins is compared to typical rigid cycloaliphatic resins; furthermore, high water resistance of the cured resins is suggested to be attributed to the hydrophobic character of the C[sub 8] chain by cross-linking.

  18. An insight of traditional plasmid curing in Vibrio species

    PubMed Central

    Letchumanan, Vengadesh; Chan, Kok-Gan; Lee, Learn-Han

    2015-01-01

    As the causative agent of foodborne related illness, Vibrio species causes a huge impact on the public health and management. Vibrio species is often associated with seafood as the latter plays a role as a vehicle to transmit bacterial infections. Hence, antibiotics are used not to promote growth but rather to prevent and treat bacterial infections. The extensive use of antibiotics in the aquaculture industry and environment has led to the emerging of antibiotic resistant strains. This phenomenon has triggered an alarming public health concern due to the increase number of pathogenic Vibrio strains that are resistant to clinically used antibiotics and is found in the environment. Antibiotic resistance and the genes location in the strains can be detected through plasmid curing assay. The results derived from plasmid curing assay is fast, cost effective, sufficient in providing insights, and influence the antibiotic management policies in the aquaculture industry. This presentation aims in discussing and providing insights on various curing agents in Vibrio species. To our best of knowledge, this is a first review written discussing on plasmid curing in Vibrio species. PMID:26347714

  19. Infiltration/cure modeling of resin transfer molded composite materials using advanced fiber architectures

    NASA Technical Reports Server (NTRS)

    Loos, Alfred C.; Weideman, Mark H.; Long, Edward R., Jr.; Kranbuehl, David E.; Kinsley, Philip J.; Hart, Sean M.

    1991-01-01

    A model was developed which can be used to simulate infiltration and cure of textile composites by resin transfer molding. Fabric preforms were resin infiltrated and cured using model generated optimized one-step infiltration/cure protocols. Frequency dependent electromagnetic sensing (FDEMS) was used to monitor in situ resin infiltration and cure during processing. FDEMS measurements of infiltration time, resin viscosity, and resin degree of cure agreed well with values predicted by the simulation model. Textile composites fabricated using a one-step infiltration/cure procedure were uniformly resin impregnated and void free. Fiber volume fraction measurements by the resin digestion method compared well with values predicted using the model.

  20. Curing Composite Materials Using Lower-Energy Electron Beams

    NASA Technical Reports Server (NTRS)

    Byrne, Catherine A.; Bykanov, Alexander

    2004-01-01

    In an improved method of fabricating composite-material structures by laying up prepreg tapes (tapes of fiber reinforcement impregnated by uncured matrix materials) and then curing them, one cures the layups by use of beams of electrons having kinetic energies in the range of 200 to 300 keV. In contrast, in a prior method, one used electron beams characterized by kinetic energies up to 20 MeV. The improved method was first suggested by an Italian group in 1993, but had not been demonstrated until recently. With respect to both the prior method and the present improved method, the impetus for the use of electron- beam curing is a desire to avoid the high costs of autoclaves large enough to effect thermal curing of large composite-material structures. Unfortunately, in the prior method, the advantages of electron-beam curing are offset by the need for special walls and ceilings on curing chambers to shield personnel from x rays generated by impacts of energetic electrons. These shields must be thick [typically 2 to 3 ft (about 0.6 to 0.9 m) if made of concrete] and are therefore expensive. They also make it difficult to bring large structures into and out of the curing chambers. Currently, all major companies that fabricate composite-material spacecraft and aircraft structures form their layups by use of automated tape placement (ATP) machines. In the present improved method, an electron-beam gun is attached to an ATP head and used to irradiate the tape as it is pressed onto the workpiece. The electron kinetic energy between 200 and 300 keV is sufficient for penetration of the ply being laid plus one or two of the plies underneath it. Provided that the electron-beam gun is properly positioned, it is possible to administer the required electron dose and, at the same time, to protect personnel with less shielding than is needed in the prior method. Adequate shielding can be provided by concrete walls 6 ft (approximately equal to 1.8 m) high and 16 in. (approximately

  1. Anti-TMV activity flavones from the leaves of Yunnan local air cured tobacco.

    PubMed

    Miao, Ming-Ming; Li, Lan; Shen, Qin-Peng; Liu, Chun-Bo; Li, Yin-Ke; Zhang, Tao; Zhang, Feng-Mei; He, Pei; Wang, Kun-Miao; Zhu, Rui-Zhi; Chen, Yong-Kuan; Yang, Guang-Yu

    2015-06-01

    Four new flavones, tobaflavones E-H (1-4), together with two known flavones (5 and 6), were isolated from the leaves of Dali Tiandeng tobacco (a variety of Yunnan local air cured tobacco). Their structures were elucidated by spectroscopic methods, including extensive 1D- and 2D NMR techniques. Compound 2 is the first naturally occurring flavone bearing a (4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)methyl moiety. These compounds were also evaluated for their anti-tobacco mosaic virus (anti-TMV) activity. The results revealed that compounds 1 and 2 exhibited high anti-TMV activity with inhibition rate of 35.3% and 39.6%, respectively. The rates are higher than those of positive control. The other compounds also showed potential anti-TMV activity with inhibition rates in the range of 18.7-28.4%, respectively.

  2. Comparative study of optical fiber cure-monitoring methods

    NASA Astrophysics Data System (ADS)

    Crosby, Peter A.; Powell, Graham R.; Fernando, Gerard F.; Waters, David N.; France, Chris M.; Spooncer, Ronald C.

    1997-06-01

    This paper reports on a comparative study undertaken for different types of optical fiber sensor developed to monitor the cure of an epoxy resin system. The optical fiber sensors used to monitor the cure process were based on transmission spectroscopy, evanescent wave spectroscopy and refractive index monitoring. The transmission sensor was prepared by aligning two optical fibers within a specially prepared sleeve with a gap between the optical fiber end-faces. During cure, resin from the specimen flowed into the gap between the optical fibers allowing transmission spectra of the resin to be obtained. The evanescent wave sensor was prepared by stripping the cladding from a high refractive index core optical fiber. The prepared sensor was embedded in the sample and attenuated total reflectance spectra recorded from the resin/core boundary. Refractive index monitoring was undertaken using a high refractive index core optical fiber which had a small portion of its cladding removed. The prepared sensor was embedded in the resin specimen and light from a single wavelength source was launched into the fiber. Changes in the guiding characteristics of the sensor due to refractive index changes at the resin/core boundary were used to monitor the progress of the cure reaction. The transmission and evanescent wave spectroscopy sensors were used to follow changes in characteristic near-infrared absorption bands of the resin over the range 1450 - 1700 nm during the cure reaction. Consequently these techniques required tunable wavelength sources covering specific wavelength ranges. However, the refractive index based sensor used a single wavelength source. Therefore the equipment costs for this type of sensor were considerably less. Additionally, the refractive index sensor did not require a single wavelength source at any particular wavelength and could be applied to any spectral region in which the optical fiber would transmit light. The advantages and disadvantages of these

  3. Light output from six battery operated dental curing lights.

    PubMed

    Shimokawa, Carlos Alberto Kenji; Turbino, Míriam Lacalle; Harlow, Jessie Eudora; Price, Hannah Louise; Price, Richard Bengt

    2016-12-01

    Light Curing Units (LCUs) are used daily in almost every dental office to photocure resins, but because the light is so bright, the user is unable to tell visually if there are any differences between different LCUs. This study evaluated the light output from six dental LCUs: Elipar Deep Cure-S (3M ESPE), Bluephase G2 (Ivoclar Vivadent), Translux 2Wave (Heraeus Kulzer), Optilight Prime (Gnatus), Slim Blast (First Medica) and Led.B (Guilin Woodpecker) with a fully charged battery, after 50, and again after 100, 20second light exposures. For each situation, the radiant power was measured 10 times with a laboratory-grade power meter. Then, the emission spectrum was measured using a fiber-optic spectrometer followed by an analysis of the light beam profile. It was found there were significant differences in the LCU power and the irradiance values between the LCUs (p<0.01). The Optilight Prime and Slim Blast LCUs showed a significant reduction in light output after a 50 and 100 exposures, while Bluephase G2 exhibited a significant reduction only after 100 exposures (p<0.01). The Bluephase G2 and Translux 2Wave delivered an emission spectrum that had two distinct wavelength emission peaks. Only the Elipar Deep Cure-S and Bluephase G2 LCUs displayed homogeneous light beam profiles, the other LCUs exhibited highly non-homogeneous light beam profiles. It was concluded that contemporary LCUs could have very different light output characteristics. Both manufacturers and researchers should provide more information about the light output from LCUs.

  4. Rapid exploration of curing process design space for production of controlled-release pellets.

    PubMed

    Kristan, Katja; Horvat, Matej

    2012-10-01

    Time and cost are among the most often cited hurdles limiting the rate and extent of adoption of Quality by Design (QbD) and Process Analytical Technology. In this article, we demonstrate that, with appropriate techniques, a key QbD element can be achieved with amount of resources comparable to classical development approach. To control the dissolution rate of a highly soluble drug substance from latex polymer coated pellets, we have examined the effect of key variables affecting the curing process step by an experimental design study. To explore and characterize the Design Space, we have produced and tested 62 distinct pellet samples. To achieve this in a reasonable amount of time, we have developed a scaled-down automated dissolution method that demonstrated excellent correlation to the classical method. By careful planning of experimentation, we were able to obtain all samples from just two batches of pellet cores. The curing process Design Space was explored by statistical modeling of samples obtained from the first batch. Robustness and repeatability of the Design Space at the edge of failure was preliminarily investigated by analysis of selected samples from the second batch with encouraging results.

  5. Characterization of UV-cured gel polymer electrolytes for rechargeable lithium batteries

    NASA Astrophysics Data System (ADS)

    Song, Min-Kyu; Cho, Jin-Yeon; Cho, Byung Won; Rhee, Hee-Woo

    Novel ultraviolet (UV)-cured gel polymer electrolytes based on polyethyleneglycol diacrylate (PEGDA) oligomer and polyvinylidene fluoride (PVdF) are prepared and characterized. UV-curing of PEGDA oligomer containing PVdF and ethylene carbonate (EC)-based liquid electrolyte yields chemically and physically cross-linked PEGDA/PVdF blend gel electrolytes. PEGDA/PVdF blend films show much higher mechanical properties and electrolyte liquid retention than pure PEGDA film. The ionic conductivity ( σ) of a PEGDA/PVdF (5/5) blend electrolyte reaches about 4 mS cm -1 at ambient temperature and is as high as 1 mS cm -1 at 0 °C. All the blend electrolytes are electrochemically stable up to 4.6 V versus Li/Li +. The cation transference number ( t+) measured by dc micropolarization exceeds 0.5 at room temperature. Li/(PEGDA/PVdF)/LiCoO 2 cells ( 2 cm×2 cm) retains >91% of its initial discharge capacity after 50 cycles at the C/3 rate (2 mA cm -2) and delivers about 70% of full capacity with an average load voltage of 3.6 V at the C/1 rate. Cell performance is stable up to 80 °C because PVdF chains might be stabilized by entanglement with the chemically cross-linked PEGDA network structure.

  6. Investigation of adhesive bond cure conditions using nonlinear ultrasonic methods

    NASA Astrophysics Data System (ADS)

    Berndt, Tobias Paul

    2000-09-01

    Various linear and nonlinear ultrasonic methods with water coupling have been used to study aluminum-adhesive- aluminum laminates, prepared under different adhesive curing conditions, for possible nondestructive bond strength determination. Although our improperly cured adhesive bonds are expected to exhibit a reduced adhesion strength, ultrasonic characterization of all samples using small-amplitude techniques did not reveal differences between the various samples. The ill-cured bonds appear to differ from the well-cured ones only in their acoustic velocities in the adhesive. Thus, the ill-cured adhesives exhibit longitudinal and shear wave velocities that are several percent higher than in the normal-cured adhesives. Therefore, in the course of a larger research effort, we have investigated a variety of finite-amplitude experimental methods for the acquisition of data that would possibly allow to differentiate the various cure conditions as well as the degree of adhesion. For example, we have explored numerous normal and oblique incidence approaches, that are based on nonlinear harmonic generation, and we have explored several non- collinear two-wave interaction approaches. In this dissertation, we report on theoretical aspects and experimental results obtained so far using different normal incidence setups. First, we discuss an approach in which the sample is mechanically scanned in various ways with respect to the focus of a transmitting transducer that is operated at one frequency and one excitation level. Subsequently, we discuss several variable excitation frequency and variable excitation level setups. Due to a combination of complicating factors, even if powerful sample-related resonances via a frequency scanning approach are exploited, it is extremely difficult to isolate the nonlinear characteristics of an adhesive bond. However, a multi-frequency multi-power approach has been quite successful in acquiring nonlinear ultrasonic data that appears to be

  7. [Spatial and temporal characteristics of flue-cured tobacco water requirement and irrigation requirement index in Yunnan Province, China].

    PubMed

    Zheng, Dong-fang; Xu, Jia-yang; Lu, Xiu-ping; Xu, Zi-cheng; Li, Jun-ying; Pang, Tao; Zhang, Ya-jie; Wang, Pei-wen

    2015-07-01

    Based on the daily meteorological data of 124 agricultural meteorological sites during 1977-2010 in Yunnan Province, using recommended Penman-Monteith formula by FAO, water requirement and irrigation requirement index in the growth period of flue-cured tobacco were calculated to analyze their spatial and temporal characteristics and change patterns. The results showed that water requirements of flue-cured tobacco in root extending, vigorous, mature periods and field growth period during 1977-2010 were 76.73-174.73, 247.50-386.64, 180.28-258.14 and 528.18-764.08 mm, respectively, and the water requirement of vigorous period was the highest. The average irrigation demand index of each period was -0.02, 0.38, 0.17 and 0.26, respectively. Effective precipitation could meet the demand of flue-cured tobacco in root extending period. Water requirement of flue-cured tobacco in Yunnan Province decreased annually, and the rates of water requirement under the climate change trend in the four periods abovementioned were -12. 42, -21.46, -7.17 and -47.15 mm . (10 a)-1, respectively. The smallest irrigation demand index was observed in Dehong, and the largest in Diqing. The irrigation demand indexes of Dehong, Xishuangbanna and Puer regions were negative in flue-cured tobacco field growth period. The reference crop evapotranspiration, water requirement and effective precipitation decreased, but the irrigation requirement and irrigation requirement index increased with the increase of latitude. The effective precipitation decreased, but the irrigation requirement and irrigation requirement index increased with the increase of altitude.

  8. Decreased Cutaneous Resonance Running Time in Cured Leprosy Subjects

    PubMed Central

    Song, S.P.; Elias, P.M.; Lv, C.Z.; Shi, Y.J.; Guang, P.; Zhang, X.J.; Feingold, K.R.; Man, M.Q.

    2009-01-01

    Background/Objectives Leprosy prominently involves both the skin and peripheral neural tissues and some symptoms persist after microbial cure. Because alterations in the dermis also occur in leprosy, we assessed here whether there were changes in cutaneous resonance running time (CRRT), a parameter that is influenced by collagen properties, in cured leprosy subjects. Methods A reviscometer was used to measure the CRRT at various directions on the dorsal hand and the flexural forearms of 76 cured leprosy subjects aged 50–85 years and 68 age-matched normal subjects. Results In comparison to normal subjects, CRRTs on the hands and the forearms were significantly reduced in all directions in cured leprosy, except at the 1–7, 2–8 and 3–9 o'clock directions on the forearms. CRRTs were reduced significantly at both the 4–10 and 5–11 o'clock directions on the forearm in lepromatous (73.33 ± 4.19 at 4–10 o'clock and 67.44 ± 2.71 at 5–11 o'clock direction) and borderline lepromatous types (77.58 ± 5.84 at 4–10 o'clock and 79.85 ± 6.81 at 5–11 o'clock direction) as compared with normal (143.10 ± 7.75 at 4–10 o'clock and 125.18 ± 8.14 at 5–11 o'clock direction). On the hand, CRRTs at all directions, except that at 4–10 o'clock direction, were also significantly reduced in lepromatous and borderline lepromatous types in comparison with normal. Significant differences in CRRT at some directions were found among the various subtypes of leprosy. Conclusion CRRTs were abnormal in the cured leprosy subjects as a whole, but varied with leprosy subtypes, which suggested that the extent of reduction of CRRTs correlates with the severity of immune alteration. These results suggest that CRRT measurements could be a useful approach to quantify the extent of some residual abnormalities in cured leprosy and perhaps could also be used to evaluate the efficacy of treatment. PMID:19648783

  9. Progress Toward HIV Eradication: Case Reports, Current Efforts, and the Challenges Associated with Cure.

    PubMed

    Martin, Alyssa R; Siliciano, Robert F

    2016-01-01

    An estimated 35 million people worldwide are infected with HIV, yet a widely applicable cure strategy remains elusive. Recent case reports have suggested that curing HIV infection is possible, renewing excitement about research efforts. We describe those cases and discuss their relevance to the global HIV epidemic. We also review ongoing cure strategies that are transitioning from the lab to the clinic, and the assays and clinical assessments that can be used to evaluate cure interventions.

  10. Variable frequency microwave (VFM) curing, processing of thermoset prepreg laminates. Final report

    SciTech Connect

    Paulauskas, F.L.

    1996-09-30

    The objective of this work was to investigate the beneficial effect of the variable frequency microwave (VFM) technology to cure thermosetting prepreg laminates. Further, it was to investigate the interrelationship and effect on the curing process of frequency, band width, and curing time with different types of laminates. Previous studies of microwave-assisted curing of neat resins (epoxy) and unidirectional glass and carbon fiber laminates with a fixed frequency of 2.45 GHz, have shown that a substantial reduction in the curing time was obtained. Results of this earlier work indicate that the microwave-assisted curing of multidirectional glass fiber laminates also show a substantial reduction of the required curing time. This may be explained by the penetration of microwave energy directly and throughout the laminate with enhancement of the kinetics of the chemical reaction. The fixed frequency microwave radiation of 2.45 GHz has been demonstrated to be a partially acceptable method to cure unidirectional carbon fiber laminates. Multidirectional carbon fiber/epoxy laminates demonstrate a lack of coupling during the curing process. A direct curing of these laminates was not possible by microwave radiation with the experimental approach used in agreement with previous work. In addition to this short coming, the unidirectional laminate samples cured with the fixed frequency are visually nonuniform. Localized areas of darker colors (burn, hot spots, overheating) are attributed to the formation of standing waves within the microwave cavity. For this reason, the laminates are subject to proper rotation while curing through fixed frequency. The present research indicates that variable frequency microwave technology is a sound and acceptable processing method to effectively cure uni-, bi- or multi-directional thermosetting glass fiber laminates. Also, this methodology will effectively cure unidirectional thermosetting carbon fiber laminates. For all these cases, this

  11. Differential scanning calorimetry investigation on vinyl ester resin curing process for polymer nanocomposite fabrication.

    PubMed

    Guo, Zhanhu; Ng, Ho Wai; Yee, Gary L; Hahn, H Thomas

    2009-05-01

    Two different ceramic (cerium oxide and titanium oxide) nanoparticles were introduced into vinyl ester resin for nanocomposite fabrication. The curing process of the vinyl ester resin was investigated by a differential scanning calorimetery (DSC). The incorporation of nanoparticles in the resin affects the curing process due to the physicochemical interaction between the nanoparticles and the polymer matrix. The particle loading has a significant effect on the initial and peak curing temperatures, reaction heat and curing extent. The fully cured vinyl ester resin nanocomposites reinforced with cerium oxide nanoparticles were fabricated after a 24-hour room temperature curing and a one-hour postcuring at 85 degrees C. Particle functionalization favors the composite fabrication with a higher curing extent after room-temperature curing as compared to the as-received nanoparticle filled vinyl ester resin nanocomposites. The nanofiller materials were observed to significantly affect the curing process. In comparison to cerium oxide nanoparticles, titanium oxide nanoparticles prohibit the curing process with a much higher initiating curing temperatures. The fully cured nanocomposites reinforced with titanium oxide nanoparticles were fabricated by one-hour postcuring at 85 degrees C.

  12. Curing Behavior and Viscoelasticity of Dual-Curable Adhesives Based on High-Reactivity Azo Initiator

    NASA Astrophysics Data System (ADS)

    Lee, Jong-Gyu; Shim, Gyu-Seong; Park, Ji-Won; Kim, Hyun-Joong; Moon, Sang-Eun; Kim, Young-Kwan; No, Dong-Hun; Kim, Jong-Hwan; Han, Kwan-Young

    2016-07-01

    We have investigated the curing behavior of dual-curable acrylic resin to solve problems associated with curing of adhesives in shaded areas during display manufacture. A low-temperature curing-type thermal initiator, 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), with a 30°C half-life decomposition temperature was used in the investigation. Dual-curable adhesives were prepared according to the thermal initiator content and ultraviolet (UV) radiation dose. The effects of thermal initiator and UV irradiation on the curing behavior and viscoelasticity were investigated. Using Fourier-transform infrared spectroscopy and gel-fraction analysis, an evaluation was carried out to determine the degree of curing after dual UV/thermal curing. In addition, the real-time curing behavior was evaluated using thermogravimetric analysis, differential scanning calorimetry, and a UV/advanced rheometric expansion system. A lift-off test was carried out to verify the effects of dual curing on adhesion performance. Application of UV irradiation before thermal curing suppressed the thermal curing efficiency. Also, the network structure formed after dual curing with low UV dose showed higher crosslinking density. Therefore, the thermal initiator radical effectively influenced uncured areas with low curing temperature and initiator content without causing problems in UV-curable zones.

  13. Health aspects of the curing of synthetic rubbers.

    PubMed Central

    Fraser, D A; Rappaport, S

    1976-01-01

    A commonly used tread rubber formulation was cured in the laboratory under conditions simulating vulcanization in the Bag-O-Matic press. Volatile emissions were collected on charcoal and analyzed by combined GC-mass spectrometry. The compounds identified were either contaminants present in the raw material or reaction products. Some of these compounds were also identified in charcoal tube samples collected in the atmosphere of the industrial operations. Estimates based on the loss of weight of rubber during curing were used to predict airborne concentrations and compared to the concentrations actually found. The literature of the toxicity of raw materials and effluents was reviewed, and no acute or chronic toxicological effects would be anticipated. Information concerning potential carcinogenicity was not available and could not be evaluated. PMID:1026417

  14. Gene Therapy to Cure HIV: Where to from Here?

    PubMed

    Johnston, Rowena

    2016-12-01

    A variety of approaches are being tested to cure HIV, but with the exception of the Berlin patient case, none has been successful. The Berlin patient, positive for both HIV and acute myeloid leukemia (AML), received two stem cell transplants from a donor homozygous for the CCR5delta32 mutation. In the 8 years since his second transplant, he has remained free of both HIV and AML. This case provides strong proof-of-principle that a cure for HIV is possible and might be achieved through gene therapy. Several technological barriers must be resolved and are discussed here, including the safe delivery of the intervention throughout the body of the infected person, increased efficiency of gene editing, and avoidance of resistance to the therapy. Delivery of a gene therapy intervention to HIV-infected people around the world will also be a considerable challenge.

  15. Eradication of HIV and Cure of AIDS, Now and How?

    PubMed

    Zhang, Jielin; Crumpacker, Clyde

    2013-10-18

    Recent studies have highlighted the importance of eradication of human immunodeficiency virus (HIV) and cure of acquired immunodeficiency syndrome (AIDS). However, a pivotal point that the patient immunity controls HIV reactivation after highly active anti-retroviral therapy [HAART or combination anti-retroviral therapy (cART)] remains less well addressed. In spite of the fact that both innate and adaptive immunities are indispensable and numerous cells participate in the anti-HIV immunity, memory CD4 T-cells are indisputably the key cells organizing all immune actions against HIV while being the targets of HIV. Here we present a view and multidisciplinary approaches to HIV/AIDS eradication and cure. We aim at memory CD4 T-cells, utilizing the stem cell properties of these cells to reprogram an anti-HIV memory repertoire to eliminate the viral reservoir, toward achieving an AIDS-free world.

  16. Eradication of HIV and Cure of AIDS, Now and How?

    PubMed Central

    Zhang, Jielin; Crumpacker, Clyde

    2013-01-01

    Recent studies have highlighted the importance of eradication of human immunodeficiency virus (HIV) and cure of acquired immunodeficiency syndrome (AIDS). However, a pivotal point that the patient immunity controls HIV reactivation after highly active anti-retroviral therapy [HAART or combination anti-retroviral therapy (cART)] remains less well addressed. In spite of the fact that both innate and adaptive immunities are indispensable and numerous cells participate in the anti-HIV immunity, memory CD4 T-cells are indisputably the key cells organizing all immune actions against HIV while being the targets of HIV. Here we present a view and multidisciplinary approaches to HIV/AIDS eradication and cure. We aim at memory CD4 T-cells, utilizing the stem cell properties of these cells to reprogram an anti-HIV memory repertoire to eliminate the viral reservoir, toward achieving an AIDS-free world. PMID:24151495

  17. Ultraviolet curing for surface modification of textile fabrics.

    PubMed

    Ferrero, Franco; Periolatto, Monica

    2011-10-01

    In this study, cotton, polyester and polyamide fabrics were treated by radical or cationic ultraviolet curing of different commercial products conferring water and oil repellency. Moreover, radical ultraviolet curing of chitosan was applied to confer antimicrobial properties. The advantages of this technology are well known making it very interesting for industrial applications: energy savings, low environmental impact, simple, cheap and small equipment, high treatment speed. The polymerization was controlled through weight gain and gel content measurements, while the properties of hydro and oil repellency were determined in terms of contact angle, moisture adsorption and water vapor permeability. The polymer distribution on fabric surfaces was investigated by scanning electron microscopy and atomic force microscopy. However the fabrics treated with chitosan were subjected to the standard test for determining the antimicrobial activity. Finally the finished cotton samples were subjected to washing fastness tests.

  18. In-situ cure monitoring of advanced composite materials

    NASA Astrophysics Data System (ADS)

    Saliba, Tony; Saliba, Susan; Lanzafame, John; Gudeman, Linda

    Automatic process control and optimization depends on the ability to effectively determine the state of the process. In-situ sensors capable of monitoring the physical and chemical changes are therefore essential. The use of an in-situ acoustic ultrasonic sensor to monitor the cure characteristics of Bismaleimides (BMI) based composite materials was investigated. The acoustic attenuation reflects changes in the viscosity of the resin. The effects on the acoustic response curve of laminate thickness, ply orientation as well as the type of BMI were studied. A general correlation relating the acoustic attenuation of a curing BMI composite to the actual viscosity was developed. The results obtained for BMI were compared to those obtained from epoxy based composite materials.

  19. Vacuum deposition and curing of liquid monomers apparatus

    DOEpatents

    Affinito, John D.

    1996-01-01

    The present invention is the formation of solid polymer layers under vacuum. More specifically, the present invention is the use of "standard" polymer layer-making equipment that is generally used in an atmospheric environment in a vacuum, and degassing the monomer material prior to injection into the vacuum. Additional layers of polymer or metal or oxide may be vacuum deposited onto solid polymer layers. Formation of polymer layers under a vacuum improves material and surface characteristics, and subsequent quality of bonding to additional layers. Further advantages include use of less to no photoinitiator for curing, faster curing, fewer impurities in the polymer electrolyte, as well as improvement in material properties including no trapped gas resulting in greater density, and reduced monomer wetting angle that facilitates spreading of the monomer and provides a smoother finished surface.

  20. Vacuum deposition and curing of liquid monomers apparatus

    DOEpatents

    Affinito, J.D.

    1996-08-20

    The present invention is the formation of solid polymer layers under vacuum. More specifically, the present invention is the use of ``standard`` polymer layer-making equipment that is generally used in an atmospheric environment in a vacuum, and degassing the monomer material prior to injection into the vacuum. Additional layers of polymer or metal or oxide may be vacuum deposited onto solid polymer layers. Formation of polymer layers under a vacuum improves material and surface characteristics, and subsequent quality of bonding to additional layers. Further advantages include use of less to no photoinitiator for curing, faster curing, fewer impurities in the polymer electrolyte, as well as improvement in material properties including no trapped gas resulting in greater density, and reduced monomer wetting angle that facilitates spreading of the monomer and provides a smoother finished surface. 3 figs.

  1. Discrimination of Epoxy Curing by High Lamb Modes Order

    NASA Astrophysics Data System (ADS)

    Gauthier, Camille; Leduc, Damien; Galy, Jocelyne; Elkettani, Mounsif Echherif; Izbicki, Jean-Louis

    This work is a contribution to the non destructive testing of structural adhesive bonding by ultrasonic methods. The aim of this paper is to link acoustic behaviors of epoxy bulk samples to their level of cure, quantified by a partial or a total epoxy conversion. The bulk longitudinal and shear waves velocities are measured for each sample. They are used to determine the theoretical dispersion curves of Lamb waves. Theoretical results predict a high sensitivity of some high order Lamb modes to the cure level by the variation of their wavenumber, for a given mode and for the same frequency range. In parallel, an experimental study is conducted to determine the experimental dispersion curves. The experimental results and the predicted ones are in a good agreement.

  2. Cure violence: a public health model to reduce gun violence.

    PubMed

    Butts, Jeffrey A; Roman, Caterina Gouvis; Bostwick, Lindsay; Porter, Jeremy R

    2015-03-18

    Scholars and practitioners alike in recent years have suggested that real and lasting progress in the fight against gun violence requires changing the social norms and attitudes that perpetuate violence and the use of guns. The Cure Violence model is a public health approach to gun violence reduction that seeks to change individual and community attitudes and norms about gun violence. It considers gun violence to be analogous to a communicable disease that passes from person to person when left untreated. Cure Violence operates independently of, while hopefully not undermining, law enforcement. In this article, we describe the theoretical basis for the program, review existing program evaluations, identify several challenges facing evaluators, and offer directions for future research.

  3. Early hardness and shear bond strength of dual-cure resin cement light cured through resin overlays with different dentin-layer thicknesses.

    PubMed

    Chang, H-S; Kim, J-W

    2014-01-01

    The purpose of this study was to investigate whether dentin-layer thickness of resin overlays could affect the early hardness and shear bond strength of dual-cure resin cement (DCRC, RelyX ARC) after light curing with light curing units (LCUs) of various power densities: Optilux 360 (360), Elipar Freelight 2 (FL2), and Elipar S10 (S10). Resin overlays were fabricated using an indirect composite resin (Sinfony) with a dentin layer, an enamel layer, and a translucent layer of 0.5 mm thickness each (0.5-0.5-0.5) or of 0.2 mm, 0.5 mm, and 0.8 mm thickness (0.2-0.5-0.8), respectively. The DCRC was light cured for 40 seconds through the overlays, and surface hardness and shear bond strength to bovine dentin were tested 10 minutes after the start of light curing. Surface hardness was higher when the DCRC was light cured through the 0.2-0.5-0.8 combination than when the DCRC was light cured through the 0.5-0.5-0.5 combination with all LCUs. The ratio of upper surface hardness of DCRC light cured through resin overlays relative to the upper surface hardness of DCRC light cured directly was more than 90% only when the DCRC was light cured with S10 through the 0.2-0.5-0.8 combination. The shear bond strength value was higher when the DCRC was light cured with S10 through the 0.2-0.5-0.8 combination than when light cured with S10 through the 0.5-0.5-0.5 combination. This study indicates that reducing the dentin-layer thickness while increasing the translucent-layer thickness of resin inlays can increase the photopolymerization of DCRC, thereby increasing the early bond strength of resin inlays to dentin.

  4. Exploratory Development of an Ultra-Fast-Curing Wound Dressing

    DTIC Science & Technology

    1989-11-30

    mwv’eri if neceswey ". idientify by block number) eare developing a drug -dispensing field dermal dressing. The dermal dressing, which can be easily applied...polyurethane oligomer which is designed to cure at room temperature and Oelivers drugs on a controlled, sustainedI and highly reproducible basis.i I 20...3 ITASK I .......................................... 5 A. OPTIMIZE DISPERSION OF THE DRUGS ........ 5 B 5. UTILIZE MORE POTENT DRUGS

  5. On the probability of cure for heavy-ion radiotherapy.

    PubMed

    Hanin, Leonid; Zaider, Marco

    2014-07-21

    The probability of a cure in radiation therapy (RT)-viewed as the probability of eventual extinction of all cancer cells-is unobservable, and the only way to compute it is through modeling the dynamics of cancer cell population during and post-treatment. The conundrum at the heart of biophysical models aimed at such prospective calculations is the absence of information on the initial size of the subpopulation of clonogenic cancer cells (also called stem-like cancer cells), that largely determines the outcome of RT, both in an individual and population settings. Other relevant parameters (e.g. potential doubling time, cell loss factor and survival probability as a function of dose) are, at least in principle, amenable to empirical determination. In this article we demonstrate that, for heavy-ion RT, microdosimetric considerations (justifiably ignored in conventional RT) combined with an expression for the clone extinction probability obtained from a mechanistic model of radiation cell survival lead to useful upper bounds on the size of the pre-treatment population of clonogenic cancer cells as well as upper and lower bounds on the cure probability. The main practical impact of these limiting values is the ability to make predictions about the probability of a cure for a given population of patients treated to newer, still unexplored treatment modalities from the empirically determined probability of a cure for the same or similar population resulting from conventional low linear energy transfer (typically photon/electron) RT. We also propose that the current trend to deliver a lower total dose in a smaller number of fractions with larger-than-conventional doses per fraction has physical limits that must be understood before embarking on a particular treatment schedule.

  6. On the probability of cure for heavy-ion radiotherapy

    NASA Astrophysics Data System (ADS)

    Hanin, Leonid; Zaider, Marco

    2014-07-01

    The probability of a cure in radiation therapy (RT)—viewed as the probability of eventual extinction of all cancer cells—is unobservable, and the only way to compute it is through modeling the dynamics of cancer cell population during and post-treatment. The conundrum at the heart of biophysical models aimed at such prospective calculations is the absence of information on the initial size of the subpopulation of clonogenic cancer cells (also called stem-like cancer cells), that largely determines the outcome of RT, both in an individual and population settings. Other relevant parameters (e.g. potential doubling time, cell loss factor and survival probability as a function of dose) are, at least in principle, amenable to empirical determination. In this article we demonstrate that, for heavy-ion RT, microdosimetric considerations (justifiably ignored in conventional RT) combined with an expression for the clone extinction probability obtained from a mechanistic model of radiation cell survival lead to useful upper bounds on the size of the pre-treatment population of clonogenic cancer cells as well as upper and lower bounds on the cure probability. The main practical impact of these limiting values is the ability to make predictions about the probability of a cure for a given population of patients treated to newer, still unexplored treatment modalities from the empirically determined probability of a cure for the same or similar population resulting from conventional low linear energy transfer (typically photon/electron) RT. We also propose that the current trend to deliver a lower total dose in a smaller number of fractions with larger-than-conventional doses per fraction has physical limits that must be understood before embarking on a particular treatment schedule.

  7. Curing preceramic polymers by exposure to nitrogen dioxide

    NASA Technical Reports Server (NTRS)

    Rabe, James A. (Inventor); Lipowitz, Jonathan (Inventor); Lu, Paul P. (Inventor)

    1991-01-01

    A rapid method of infusibilizing (curing) preceramic polymers comprising treatment said polymers with gaseous nitrogen dioxide. The infusibilized polymers may be pyrolyzed to temperatures in excess of about 800.degree. C. to yield ceramic materials with low oxygen content and, thus, good thermal stability. The methods are especially useful for the production of ceramic fibers and, more specifically, to the on-line production of ceramic fibers.

  8. Cure-WISE: HETDEX data reduction with Astro-WISE

    NASA Astrophysics Data System (ADS)

    Snigula, J. M.; Cornell, M. E.; Drory, N.; Fabricius, Max.; Landriau, M.; Hill, G. J.; Gebhardt, K.

    2012-09-01

    The Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) is a blind spectroscopic survey to map the evolution of dark energy using Lyman-alpha emitting galaxies at redshifts 1:9 < z < 3:5 as tracers. The survey instrument, VIRUS, consists of 75 IFUs distributed across the 22-arcmin field of the upgraded 9.2-m HET. Each exposure gathers 33,600 spectra. Over the projected five year run of the survey we expect about 170 GB of data per night. For the data reduction we developed the Cure pipeline. Cure is designed to automatically find and calibrate the observed spectra, subtract the sky background, and detect and classify different types of sources. Cure employs rigorous statistical methods and complete pixel-level error propagation throughout the reduction process to ensure Poisson-limited performance and meaningful significance values. To automate the reduction of the whole dataset we implemented the Cure pipeline in the Astro-WISE framework. This integration provides for HETDEX a database backend with complete dependency tracking of the various reduction steps, automated checks, and a searchable interface to the detected sources and user management. It can be used to create various web interfaces for data access and quality control. Astro-WISE allows us to reduce the data from all the IFUs in parallel on a compute cluster. This cluster allows us to reduce the observed data in quasi real time and still have excess capacity for rerunning parts of the reduction. Finally, the Astro-WISE interface will be used to provide access to reduced data products to the general community.

  9. Development of an Ultrafast-Curing Wound Dressing

    DTIC Science & Technology

    1985-03-15

    AD V TE4337-53-85 DEVELOPMENT OF AN SULTRAFAST-CURING WOUND DRESSING ANNUAL REPORT 0 Michael Szycher, Ph.D. and Jonathan L. Rolfe March 15, 1985...in this report are not to be construed as.. j an official Department of the Army position unless so A designated by other authorized documents. 85 12...10 037 SECURITY CLASSI’ICATION OF THIS’PAGE .... REPORT DOCUMENTATION PAGE Ia. REPORT SECURITY CLASSIFICATION lb. RESTRICTIVE MARKINGS Unc lassif ied

  10. Epoxy Nanocomposites - Curing Rheokinetics, Wetting and Adhesion to Fibers

    SciTech Connect

    Ilyin, S. O.; Kotomin, S. V.; Kulichikhin, V. G.

    2010-06-02

    Epoxy nanocomposites considered as challenging polymeric matrix for advanced reinforced plastics. Nanofillers change rheokinetics of epoxy resin curing, affect wetting and adhesion to aramid and carbon fibers. In all cases extreme dependence of adhesive strength vs filler content in the binder was observed. New experimental techniques were developed to study wettability and fiber-matrix adhesion interaction, using yarn penetration path length, aramid fiber knot pull-up test and electrical admittance of the fracture surface of CFRP.

  11. Epoxy Nanocomposites—Curing Rheokinetics, Wetting and Adhesion to Fibers

    NASA Astrophysics Data System (ADS)

    Ilyin, S. O.; Kotomin, S. V.; Kulichikhin, V. G.

    2010-06-01

    Epoxy nanocomposites considered as challenging polymeric matrix for advanced reinforced plastics. Nanofillers change rheokinetics of epoxy resin curing, affect wetting and adhesion to aramid and carbon fibers. In all cases extreme dependence of adhesive strength vs filler content in the binder was observed. New experimental techniques were developed to study wettability and fiber-matrix adhesion interaction, using yarn penetration path length, aramid fiber knot pull-up test and electrical admittance of the fracture surface of CFRP.

  12. Investigation of the curing variables of asphalt-rubber binder

    SciTech Connect

    Billiter, T.C.; Chun, J.S.; Davison, R.R.

    1996-12-31

    Currently, the paving industry utilizes a curing time of 1 hour at 177{degrees}C (350{degrees}F) for producing asphalt-rubber binder. Billiter et al. showed that at these curing conditions, 1 hour at 177{degrees}C (350{degrees}F), adding rubber to asphalt was beneficial, with the rubber improving the low-temperature creep stiffness at (-15{degrees}C (5{degrees}F)), the temperature susceptibility in the 0{degrees}C-90{degrees}C (32{degrees}F-194{degrees}F) temperature region, increasing G* and {eta}* at 60{degrees}C (140{degrees}F) and 1.0 rad/sec, and decreasing 8 at 60{degrees}C (140{degrees}F) and 1.0 rad/sec. On the other hand, Billiter et al. (2) showed that the addition of rubber was also detrimental, in that the viscosity increased significantly in the compaction temperature region of 149{degrees}C-193{degrees}C (300{degrees}F-380{degrees}F). This increased viscosity can cause compaction problems, with Allison reporting that engineers blamed the compaction problems of asphalt-rubber on undissolved crumb rubber, which they believed had no beneficial effect. Additionally, the engineers reported that improper compaction led to early road failure. This work investigates the variables of binders, curing tenperature and time, and amount of mechancial energy on asphalt properties.

  13. Structural Evolution of Silica Gel and Silsesquioxane Using Thermal Curing.

    PubMed

    Hu, Nan; Rao, YuanQiao; Sun, Shengtong; Hou, Lei; Wu, Peiyi; Fan, Shaojuan; Ye, Bangjiao

    2016-08-01

    The curing of coatings of two types of siloxane containing materials, silica gel and silsesquioxane, at a modest temperature (<280℃) was studied with in situ heating Fourier transform infrared spectroscopy (FT-IR) in combination with perturbation correlation moving window (PCMW) and two-dimensional correlation spectroscopy (2D-COS) analyses. The result revealed detailed structural evolution of these two different gels. When the silica gel was heated, (Si-O)6 rings appeared from the random Si-O-Si network formed after sol gel reaction, followed by condensation of silanol groups. Upon further heating, the existing (Si-O)4 rings were broken down and converted into (Si-O)6 structures, and finally isolated silanols appeared. The transition from (Si-O)4 rings to (Si-O)6 rings was observed by IR and further confirmed with positron annihilation lifetime spectroscopy (PALS). In comparison, during the curing of hybrid silsesquioxane, the condensation of silanols happens immediately upon heating without the rearrangement of Si-O-Si network. Afterwards, the fraction of (Si-O)6 ring structure increased. (Si-O)4 structures exhibited higher stability in hybrid silsesquioxanes. In addition, the amount of silanols in silsesquioxane continued to reduce without the generation of isolated silanol in the end. The different curing behavior of silsesquioxanes from silica gel originates from the organic groups in silsesquioxanes, which lowers the cross-linking density and reduces the rigidity of siloxane network.

  14. The electron beam cure of epoxy paste adhesives

    SciTech Connect

    Farmer, J.D.; Janke, C.J.; Lopata, V.J.

    1998-07-01

    Recently developed epoxy paste adhesives were electron beam cured and experimentally explored to determine their suitability for use in an aerospace-quality aircraft component. There were two major goals for this program. The first was to determine whether the electron beam-curable past adhesives were capable of meeting the requirements of the US Air Force T-38 supersonic jet trainer composite windshield frame. The T-38 windshield frame`s arch is currently manufactured by bonding thin stainless steel plies using an aerospace-grade thermally-cured epoxy film adhesive. The second goal was to develop the lowest cost hand layup and debulk process that could be used to produce laminated steel plies with acceptable properties. The laminate properties examined to determine adhesive suitability include laminate mechanical and physical properties at room, adhesive tack, out-time capability, and the debulk requirements needed to achieve these properties. Eighteen past adhesives and four scrim cloths were experimentally examined using this criteria. One paste adhesive was found to have suitable characteristics in each of these categories and was later chosen for the manufacture of the T-38 windshield frame. This experimental study shows that by using low-cost debulk and layup processes, the electron beam-cured past adhesive mechanical and physical properties meet the specifications of the T-38 composite windshield frame.

  15. Dataset of producing and curing concrete using domestic treated wastewater.

    PubMed

    Asadollahfardi, Gholamreza; Delnavaz, Mohammad; Rashnoiee, Vahid; Fazeli, Alireza; Gonabadi, Navid

    2016-03-01

    We tested the setting time of cement, slump and compressive and tensile strength of 54 triplicate cubic samples and 9 cylindrical samples of concrete with and without a Super plasticizer admixture. We produced concrete samples made with drinking water and treated domestic wastewater containing 300, 400 kg/m(3) of cement before chlorination and then cured concrete samples made with drinking water and treated wastewater. Second, concrete samples made with 350 kg/m(3) of cement with a Superplasticizer admixture made with drinking water and treated wastewater and then cured with treated wastewater. The compressive strength of all the concrete samples made with treated wastewater had a high coefficient of determination with the control concrete samples. A 28-day tensile strength of all the samples was 96-100% of the tensile strength of the control samples and the setting time was reduced by 30 min which was consistent with a ASTMC191 standard. All samples produced and cured with treated waste water did not have a significant effect on water absorption, slump and surface electrical resistivity tests. However, compressive strength at 21 days of concrete samples using 300 kg/m(3) of cement in rapid freezing and thawing conditions was about 11% lower than concrete samples made with drinking water.

  16. Dataset of producing and curing concrete using domestic treated wastewater

    PubMed Central

    Asadollahfardi, Gholamreza; Delnavaz, Mohammad; Rashnoiee, Vahid; Fazeli, Alireza; Gonabadi, Navid

    2015-01-01

    We tested the setting time of cement, slump and compressive and tensile strength of 54 triplicate cubic samples and 9 cylindrical samples of concrete with and without a Super plasticizer admixture. We produced concrete samples made with drinking water and treated domestic wastewater containing 300, 400 kg/m3 of cement before chlorination and then cured concrete samples made with drinking water and treated wastewater. Second, concrete samples made with 350 kg/m3 of cement with a Superplasticizer admixture made with drinking water and treated wastewater and then cured with treated wastewater. The compressive strength of all the concrete samples made with treated wastewater had a high coefficient of determination with the control concrete samples. A 28-day tensile strength of all the samples was 96–100% of the tensile strength of the control samples and the setting time was reduced by 30 min which was consistent with a ASTMC191 standard. All samples produced and cured with treated waste water did not have a significant effect on water absorption, slump and surface electrical resistivity tests. However, compressive strength at 21 days of concrete samples using 300 kg/m3 of cement in rapid freezing and thawing conditions was about 11% lower than concrete samples made with drinking water. PMID:26862577

  17. A 50-Year Journey to Cure Childhood Acute Lymphoblastic Leukemia

    PubMed Central

    Pui, Ching-Hon; Evans, William E.

    2013-01-01

    The 50th anniversary of Seminars in Hematology coincides with the 50th of St. Jude Children’s Research Hospital, and both milestones are inexorably linked to studies contributing to the cure of childhood acute lymphoblastic leukemia (ALL). We thought it fitting, therefore, to mark these events by traveling back in time to point out some of the achievements, institutions, study groups and individuals that have made cure of childhood ALL a reality. In many instances, progress was driven by new ideas, while in others it was driven by new experimental tools that allowed more precise assessment of the biology of leukemic blasts and their utility in selecting therapy. We also discuss a number of contemporary advances that point the way to exciting future directions. Whatever pathways are taken, a clear challenge will be to use emerging genome-based or immunologic-based treatment options in ways that will enhance, rather than duplicate or compromise, recent gains in outcome with classic cytotoxic chemotherapy. The theme of this journey serves as a reminder of the chief ingredient of any research directed to a catastrophic disease such as ALL. It is the audacity of a small group of investigators who confronted a childhood cancer with the goal of cure, not palliation, as their mindset. PMID:23953334

  18. Progress toward curing HIV infection with hematopoietic cell transplantation

    PubMed Central

    Petz, Lawrence D; Burnett, John C; Li, Haitang; Li, Shirley; Tonai, Richard; Bakalinskaya, Milena; Shpall, Elizabeth J; Armitage, Sue; Kurtzberg, Joanne; Regan, Donna M; Clark, Pamela; Querol, Sergio; Gutman, Jonathan A; Spellman, Stephen R; Gragert, Loren; Rossi, John J

    2015-01-01

    HIV-1 infection afflicts more than 35 million people worldwide, according to 2014 estimates from the World Health Organization. For those individuals who have access to antiretroviral therapy, these drugs can effectively suppress, but not cure, HIV-1 infection. Indeed, the only documented case for an HIV/AIDS cure was a patient with HIV-1 and acute myeloid leukemia who received allogeneic hematopoietic cell transplantation (HCT) from a graft that carried the HIV-resistant CCR5-∆32/∆32 mutation. Other attempts to establish a cure for HIV/AIDS using HCT in patients with HIV-1 and malignancy have yielded mixed results, as encouraging evidence for virus eradication in a few cases has been offset by poor clinical outcomes due to the underlying cancer or other complications. Such clinical strategies have relied on HIV-resistant hematopoietic stem and progenitor cells that harbor the natural CCR5-∆32/∆32 mutation or that have been genetically modified for HIV-resistance. Nevertheless, HCT with HIV-resistant cord blood remains a promising option, particularly with inventories of CCR5-∆32/∆32 units or with genetically modified, human leukocyte antigen-matched cord blood. PMID:26251620

  19. Engineering T Cells to Functionally Cure HIV-1 Infection

    PubMed Central

    Leibman, Rachel S; Riley, James L

    2015-01-01

    Despite the ability of antiretroviral therapy to minimize human immunodeficiency virus type 1 (HIV-1) replication and increase the duration and quality of patients' lives, the health consequences and financial burden associated with the lifelong treatment regimen render a permanent cure highly attractive. Although T cells play an important role in controlling virus replication, they are themselves targets of HIV-mediated destruction. Direct genetic manipulation of T cells for adoptive cellular therapies could facilitate a functional cure by generating HIV-1–resistant cells, redirecting HIV-1–specific immune responses, or a combination of the two strategies. In contrast to a vaccine approach, which relies on the production and priming of HIV-1–specific lymphocytes within a patient's own body, adoptive T-cell therapy provides an opportunity to customize the therapeutic T cells prior to administration. However, at present, it is unclear how to best engineer T cells so that sustained control over HIV-1 replication can be achieved in the absence of antiretrovirals. This review focuses on T-cell gene-engineering and gene-editing strategies that have been performed in efforts to inhibit HIV-1 replication and highlights the requirements for a successful gene therapy–mediated functional cure. PMID:25896251

  20. [Can we cure autism? From outcome to intervention].

    PubMed

    Alessandri, M; Thorp, D; Mundy, P; Tuchman, R F

    2005-01-15

    Outcome in autism is variable but with a significant trend toward a poor prognosis and despite reports that outcome in individuals with autism may be improving secondary to early intensive interventions there is still much to be learned about the natural history and the effects of intervention in autism spectrum disorders. While there may not be a known cure for autism, there are a number of viable treatment options available. The primary models of treatment are non pharmacological interventions that include intervention models such as applied behavior analysis and developmental and structured teaching. The role of pharmacological interventions is limited to treating specific symptoms that may be interfering with a child's ability to learn or function within a particular environment. The question of whether or not we can cure autism needs to be discussed in terms of the need to overcome the as of yet poorly understood fundamental disturbance in autism and the need to develop treatment protocols specifically targeting social deficits. At the present time, it is more appropriate to speak of our quest to understand autism than it is to speak of a cure.

  1. Long-term survival, prevalence, and cure of cancer: a population-based estimation for 818 902 Italian patients and 26 cancer types

    PubMed Central

    Dal Maso, L.; Guzzinati, S.; Buzzoni, C.; Capocaccia, R.; Serraino, D.; Caldarella, A.; Dei Tos, A. P.; Falcini, F.; Autelitano, M.; Masanotti, G.; Ferretti, S.; Tisano, F.; Tirelli, U.; Crocetti, E.; De Angelis, R.; Virdone, S.; Zucchetto, A.; Gigli, A.; Francisci, S.; Baili, P.; Gatta, G.; Castaing, M.; Zanetti, R.; Contiero, P.; Bidoli, E.; Vercelli, M.; Michiara, M.; Federico, M.; Senatore, G.; Pannozzo, F.; Vicentini, M.; Bulatko, A.; Pirino, D. R.; Gentilini, M.; Fusco, M.; Giacomin, A.; Fanetti, A. C.; Cusimano, R.

    2014-01-01

    Background Persons living after a cancer diagnosis represent 4% of the whole population in high-income countries. The aim of the study was to provide estimates of indicators of long-term survival and cure for 26 cancer types, presently lacking. Patients and methods Data on 818 902 Italian cancer patients diagnosed at age 15–74 years in 1985–2005 were included. Proportions of patients with the same death rates of the general population (cure fractions) and those of prevalent patients who were not at risk of dying as a result of cancer (cure prevalence) were calculated, using validated mixture cure models, by cancer type, sex, and age group. We also estimated complete prevalence, conditional relative survival (CRS), time to reach 5- and 10-year CRS >95%, and proportion of patients living longer than those thresholds. Results The cure fractions ranged from >90% for patients aged <45 years with thyroid and testis cancers to <10% for liver and pancreatic cancers of all ages. Five- or 10-year CRS >95% were both reached in <10 years by patients with cancers of the stomach, colon–rectum, pancreas, corpus and cervix uteri, brain, and Hodgkin lymphoma. For breast cancer patients, 5- and 10-year CRSs reached >95% after 19 and 25 years, respectively, and in 15 and 18 years for prostate cancer patients. Five-year CRS remained <95% for >25 years after cancer diagnosis in patients with liver and larynx cancers, non-Hodgkin lymphoma, myeloma, and leukaemia. Overall, the cure prevalence was 67% for men and 77% for women. Therefore, 21% of male and 31% of female patients had already reached 5-year CRS >95%, whereas 18% and 25% had reached 10-year CRS >95%. Conclusions A quarter of Italian cancer patients can be considered cured. This observation has a high potential impact on health planning, clinical practice, and patients' perspective. PMID:25149707

  2. New hepatitis C virus (HCV) drugs and the hope for a cure: concepts in anti-HCV drug development.

    PubMed

    Pawlotsky, Jean-Michel

    2014-02-01

    The development of new models and tools has led to the discovery and clinical development of a large number of new anti-hepatitis C virus (HCV) drugs, including direct-acting antivirals and host-targeted agents. Surprisingly, curing HCV infection appears to be easy with these new drugs, provided that a potent drug combination with a high barrier to resistance is used. HCV infection cure rates can be optimized by combining drugs with synergistic antiviral effects, tailoring treatment duration to the patients' needs, and/or using ribavirin. Two HCV drugs have been approved in 2011--telaprevir and boceprevir, both first-wave, first-generation NS3-4A protease inhibitors, two others in 2013/2014--simeprevir, a second-wave, first-generation NS3-4A protease inhibitor, and sofosbuvir, a nucleotide analogue inhibitor of the viral polymerase. Numerous other drugs have reached phase II or III clinical development. From 2015 and onwards, interferon-containing regimens will disappear, replaced by interferon-free regimens yielding infection cure rates over 90%. These therapies will raise new issues, including the need for broad-scale screening and access to care.

  3. Effect of base monomer's refractive index on curing depth and polymerization conversion of photo-cured resin composites.

    PubMed

    Fujita, Kou; Nishiyama, Norihiro; Nemoto, Kimiya; Okada, Tamami; Ikemi, Takuji

    2005-09-01

    In this study, we examined the effect of the transmitted amount of visible light through a resin composite on the curing depth and polymerization conversion. Transmitted amount of visible light was strongly dependent on the magnitude of refractive index difference that existed between the resin and silica filler. More specifically, the differences arose from the type of base monomer used. The transmitted amount of visible light exhibited a good correlation with the curing depth and Knoop hardness ratio of the bottom surface against the top surface of the resin composite. To improve the polymerization conversion of the cavity floor, it is important to reduce the refractive index difference that exists between the base resin and silica filler.

  4. Cure therapeutics and strategic prevention: raising the bar for mental health research.

    PubMed

    Insel, T R; Scolnick, E M

    2006-01-01

    Mental disorders cause more disability than any other class of medical illness in Americans between ages 15 and 44 years. The suicide rate is higher than the annual mortality from homicide, AIDS, and most forms of cancer. In contrast to nearly all communicable and most non-communicable diseases, there is little evidence that the morbidity and mortality from mental disorders have changed in the past several decades. Mental health advocates, including psychiatric researchers, have pointed to stigma as one of the reasons for the lack of progress with mental illnesses relative to other medical illnesses. This review considers how the expectations and goals of the research community have contributed to this relative lack of progress. In contrast to researchers in cancer and heart disease who have sought cures and preventions, biological psychiatrists in both academia and industry have set their sights on incremental and marketable advances, such as drugs with fewer adverse effects. This essay argues for approaches that can lead to cures and strategies for prevention of schizophrenia and mood disorders.

  5. Simultaneous analysis of consumer variables, acceptability and sensory characteristics of dry-cured ham.

    PubMed

    Sugimoto, Masahiro; Obiya, Shinichi; Kaneko, Miku; Enomoto, Ayame; Honma, Mayu; Wakayama, Masataka; Tomita, Masaru

    2016-11-01

    We conducted a consumer acceptability analysis of dry-cured ham based on sensory evaluation. Consumer acceptability data are rendered heterogeneous by the diverse backgrounds and assessment abilities of the participants, requiring versatile analytical methods for their interpretation. Totally, 9 sensory attributes of 12 kinds of dry-cured ham samples collected from Japan (n=9), Italy (n=1), Spain (n=1), and Germany (n=1) were tasted by 117 Japanese consumers who showed acceptable evaluation abilities during blind sampling. Common techniques, such as hierarchical clustering, principal component analysis, and external preference mapping, were simultaneously utilized to analyze each characteristics scored in modified hedonic scale. These analyses revealed the relationships between the features and preferences of the assessors. For example, consumers aged 20-30 with smoking and drinking habits preferred sweetness and saltiness, and gave high ratings to Spanish Jómon serrano and Italian prosciutto. Our approach could assist ham marketers to identify potential purchasers and the preferred characteristics of their products.

  6. The implications for the surgical community of bariatric surgery as a "cure" for type 2 diabetes.

    PubMed

    Fischer, Josef E

    2013-07-01

    The United States is in the throes of an epidemic of morbid obesity and, parenthetically, type 2 diabetes. Recent data indicate that bariatric surgery, notably Roux-en-Y gastric bypass, is valid not only for weight loss but also for a high success rate in the amelioration and perhaps "cure" of type 2 diabetes. It clearly is not weight loss alone, because the amelioration of type 2 diabetes occurs before weight loss. The mechanism needs to be elucidated and researched. For the first time since tuberculosis--before antitubercular drugs, when surgical procedures were the principal mechanism for dealing with tuberculosis--surgery has the opportunity to participate in the amelioration and perhaps cure of this epidemic and to regain its professional stature. Included in this article are the author's thoughts and suggestions on how we can keep control of weight loss and bariatric procedures that are valid treatments for morbid obesity and related type 2 diabetes. We should use this opportunity to stop the current conversion of surgeons from professionals to employees.

  7. A discrimination index for selecting markers of tumor growth dynamic across multiple cancer studies with a cure fraction.

    PubMed

    Rouam, Sigrid; Broët, Philippe

    2013-08-01

    To identify genomic markers with consistent effect on tumor dynamics across multiple cancer series, discrimination indices based on proportional hazards models can be used since they do not depend heavily on the sample size. However, the underlying assumption of proportionality of the hazards does not always hold, especially when the studied population is a mixture of cured and uncured patients, like in early-stage cancers. We propose a novel index that quantifies the capability of a genomic marker to separate uncured patients, according to their time-to-event outcomes. It allows to identify genomic markers characterizing tumor growth dynamic across multiple studies. Simulation results show that our index performs better than classical indices based on the Cox model. It is neither affected by the sample size nor the cure rate fraction. In a cross-study of early-stage breast cancers, the index allows to select genomic markers with a potential consistent effect on tumor growth dynamics.

  8. Kinetic study of polymerization/curing of filament-wound composite epoxy resin systems with aromatic diamines

    NASA Technical Reports Server (NTRS)

    Golub, M. A.; Lerner, N. R.; Hsu, M. S.

    1986-01-01

    The kinetics of polymerization/curing of a filament-wound composite epoxy resin consisting of an 80/20 DGEBA/DGEBD blend and an MDA/m-PDA blend (Tonox 60/40) was studied at various temperatures and at amine epoxy ratios between 1.1 and 4.4 by means of Fourier-transform (FT) IR and bulk viscosity measurements. The activation energy for the polymerization/curing reaction using an amine/epoxy ratio of 1.1 was 11.9 kcal/mole, in agreement with a previous value. The FT-IR conversion-time plots were fitted to a kinetic expression containing two rate constants with activation energies of 13.7 and 10.0 kcal/mole. The bulk viscosity followed the Williams et al. (1955) equation, with a Di Benedetto (1965) expression for the glass transition temperature.

  9. Tobacco, Microbes, and Carcinogens: Correlation Between Tobacco Cure Conditions, Tobacco-Specific Nitrosamine Content, and Cured Leaf Microbial Community.

    PubMed

    Law, Audrey D; Fisher, Colin; Jack, Anne; Moe, Luke A

    2016-07-01

    Tobacco-specific nitrosamines are carcinogenic N-nitrosamine compounds present at very low levels in freshly harvested tobacco leaves that accumulate during leaf curing. Formation of N-nitrosamine compounds is associated with high nitrate levels in the leaf at harvest, and nitrate is presumed to be the source from which the N-nitrosation species originates. More specifically, nitrite is considered to be a direct precursor, and nitrite is linked with N-nitrosation in many environmental matrices where it occurs via microbial nitrate reduction. Here, we initiate work exploring the role of leaf microbial communities in formation of tobacco-specific nitrosamines. Leaves from burley tobacco line TN90H were air cured under various temperature and relative humidity levels, and 22 cured tobacco samples were analyzed for their microbial communities and leaf chemistry. Analysis of nitrate, nitrite, and total tobacco-specific nitrosamine levels revealed a strong positive correlation between the three variables, as well as a strong positive correlation with increasing relative humidity during cure conditions. 16S rRNA gene amplicon sequencing was used to assess microbial communities in each of the samples. In most samples, Proteobacteria predominated at the phylum level, accounting for >90 % of the OTUs. However, a distinct shift was noted among members of the high tobacco-specific nitrosamine group, with increases in Firmicutes and Actinobacteria. Several OTUs were identified that correlate strongly (positive and negative) with tobacco-specific nitrosamine content. Copy number of bacterial nitrate reductase genes, obtained using quantitative PCR, did not correlate strongly with tobacco-specific nitrosamine content. Incomplete denitrification is potentially implicated in tobacco-specific nitrosamine levels.

  10. Consideration of drainage ditches and sediment rating cure on SWAT model performance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Water quality models most often require a considerable amount of data to be properly configured and in some cases this requires additional procedural steps prior to model applications. We examined two different scenarios of such input issues in a small watershed using the Soil and Water Assessment ...

  11. [The importance for improving the cure rate of lacrimal gland benign pleomorphic adenoma].

    PubMed

    Xiao, L H

    2016-04-11

    The pleomorphic adenoma was the most common epithelial tumor of the lacrimal gland. The 2 major factors determining the prognosis of pleophormic adenoma of lacrimal gland were likelihood of recurrence and evidence of malignant transformation. Management of the recurrent pleomorphic adenoma was difficult. Moreover, the malignant transformation was danger for life. The reason for orbital recurrent involved many factors, but the main reasons may be related to correct preoperative judgment of the nature of the tumor, taking the appropriate surgical approach and operative techniques. Long-term follow-up was available for the patient. It could help doctors detect recurrence of tumor earlier and treat it timely. (Chin J Ophthalmol, 2016, 52: 241-243).

  12. A cure shrinkage model for analyzing the stresses and strains in encapsulated assemblies

    SciTech Connect

    Chambers, R.S.; Lagasse, R.R.; Guess, T.R.; Plazek, D.J.; Bero, C.

    1992-12-31

    Electrical component assemblies are encapsulated to provide delicate parts with voltage isolation and protection against damage caused by shock, vibration, and harsh atmospheric environments. During cure, thermosetting resins shrink and harden simultaneously. If the natural deformation of the resin is constrained by adhesion to the mold or to relatively stiff embedded components, cure shrinkage stresses are generated in the encapsulant. Subsequent cooling or thermal cycling produces additional stresses that are caused by the mismatches in thermal strains among the materials in the encapsulated assembly. Although cure shrinkage stresses frequently are neglected because they are considerably smaller than thermal stresses, cure shrinkage stresses can cause delamination or fractures in the encapsulant, since the partially cured resin is not as tough as the fully cured material. Cracks generated during cure can compromise performance (e. g., permit dielectric breakdown), degrade a component`s protection, and grow under subsequent thermal cycling producing residual stresses that differ from those found in uncracked assemblies. 3 refs., 11 figs.

  13. A cure shrinkage model for analyzing the stresses and strains in encapsulated assemblies

    NASA Astrophysics Data System (ADS)

    Chambers, R. S.; Lagasse, R. R.; Guess, T. R.; Plazek, D. J.; Bero, C.

    Electrical component assemblies are encapsulated to provide delicate parts with voltage isolation and protection against damage caused by shock, vibration, and harsh atmospheric environments. During cure, thermosetting resins shrink and harden simultaneously. If the natural deformation of the resin is constrained by adhesion to the mold or to relatively stiff embedded components, cure shrinkage stresses are generated in the encapsulant. Subsequent cooling or thermal cycling produces additional stresses that are caused by the mismatches in thermal strains among the materials in the encapsulated assembly. Although cure shrinkage stresses frequently are neglected because they are considerably smaller than thermal stresses, cure shrinkage stresses can cause delamination or fractures in the encapsulant, since the partially cured resin is not as tough as the fully cured material. Cracks generated during cure can compromise performance (e.g., permit dielectric breakdown), degrade a component's protection, and grow under subsequent thermal cycling producing residual stresses that differ from those found in uncracked assemblies.

  14. A cure shrinkage model for analyzing the stresses and strains in encapsulated assemblies

    SciTech Connect

    Chambers, R.S.; Lagasse, R.R.; Guess, T.R. ); Plazek, D.J.; Bero, C. . Dept. of Materials Science and Engineering)

    1992-01-01

    Electrical component assemblies are encapsulated to provide delicate parts with voltage isolation and protection against damage caused by shock, vibration, and harsh atmospheric environments. During cure, thermosetting resins shrink and harden simultaneously. If the natural deformation of the resin is constrained by adhesion to the mold or to relatively stiff embedded components, cure shrinkage stresses are generated in the encapsulant. Subsequent cooling or thermal cycling produces additional stresses that are caused by the mismatches in thermal strains among the materials in the encapsulated assembly. Although cure shrinkage stresses frequently are neglected because they are considerably smaller than thermal stresses, cure shrinkage stresses can cause delamination or fractures in the encapsulant, since the partially cured resin is not as tough as the fully cured material. Cracks generated during cure can compromise performance (e. g., permit dielectric breakdown), degrade a component's protection, and grow under subsequent thermal cycling producing residual stresses that differ from those found in uncracked assemblies. 3 refs., 11 figs.

  15. [Effects of silicon carbide on the cure depth, hardness and compressive strength of composite resin].

    PubMed

    Wang, Ke; Lin, Yi'na; Liu, Xiaoqing

    2009-08-01

    The hardness, compressive strength and cure depth are important indices of the composite resin. This investigation was made with regard to the effects of silicon carbide on the cure depth, hardness and compressive strength of the light-curing composite resin. Different amounts of silicon carbide were added to the light-curing composite resin, which accounted for 0 wt%, 1 wt%, 0.6 wt%, 0.3 wt%, 0.1 wt%, 0.05 wt% and 0.005 wt% of the composite resin, respectively. The hardness, compressive strength and cure depth of the six afore-mentioned groups of composite resin were measured by the vernier caliper, the vickers hardness tester and the tensile strength of machine, respectively. The results showed that silicon carbide improved the hardness and compressive strength of the light-curing composite resin,when the concentration was 0.05 wt%. And the cure depth was close to that of control.

  16. Cure characterization of thick polyester composite structures using dielectric and finite difference analysis

    SciTech Connect

    Day, D.R.

    1993-12-31

    Disposable and permanently mounted dielectric sensors were used to characterize the cure in polyester sheet molding compound (SMC) at various locations through the thickness of the part in a simulated molding environment. Using established techniques, the dielectric and temperature information were combined to yield local cure state information for each sensor. Parts under five millimeters thick were found to cure rather uniformly while parts greater than this had increasing degrees of nonuniformity in cure behavior through the thickness. These observed cure state data were compared to finite difference model predictions. The model predictions, which were confirmed by the sensor cure data, may be used to optimize part design and production by predicting the curing behavior and molding cycle time required for new structures.

  17. Use of Cox's Cure Model to Establish Clinical Determinants of Long-Term Disease-Free Survival in Neoadjuvant-Chemotherapy-Treated Breast Cancer Patients without Pathologic Complete Response.

    PubMed

    Asano, Junichi; Hirakawa, Akihiro; Hamada, Chikuma; Yonemori, Kan; Hirata, Taizo; Shimizu, Chikako; Tamura, Kenji; Fujiwara, Yasuhiro

    2013-01-01

    In prognostic studies for breast cancer patients treated with neoadjuvant chemotherapy (NAC), the ordinary Cox proportional-hazards (PH) model has been often used to identify prognostic factors for disease-free survival (DFS). This model assumes that all patients eventually experience relapse or death. However, a subset of NAC-treated breast cancer patients never experience these events during long-term follow-up (>10 years) and may be considered clinically "cured." Clinical factors associated with cure have not been studied adequately. Because the ordinary Cox PH model cannot be used to identify such clinical factors, we used the Cox PH cure model, a recently developed statistical method. This model includes both a logistic regression component for the cure rate and a Cox regression component for the hazard for uncured patients. The purpose of this study was to identify the clinical factors associated with cure and the variables associated with the time to recurrence or death in NAC-treated breast cancer patients without a pathologic complete response, by using the Cox PH cure model. We found that hormone receptor status, clinical response, human epidermal growth factor receptor 2 status, histological grade, and the number of lymph node metastases were associated with cure.

  18. Cure-WISE: HETDEX Data Reduction with Astro-WISE

    NASA Astrophysics Data System (ADS)

    Snigula, J. M.; Drory, N.; Fabricius, M.; Landriau, M.; Montesano, F.; Hill, G. J.; Gebhardt, K.; Cornell, M. E.

    2014-05-01

    The Hobby-Eberly Telescope Dark Energy Experiment (HETDEX, Hill et al. 2012b) is a blind spectroscopic survey to map the evolution of dark energy using Lyman-alpha emitting galaxies at redshifts 1.9< ɀ <3.5 as tracers. The survey will use an array of 75 integral field spectrographs called the Visible Integral field Replicable Unit (IFU) Spectrograph (VIRUS, Hill et al. 2012c). The 10m HET (Ramsey et al. 1998) currently receives a wide-field upgrade (Hill et al. 2012a) to accomodate the spectrographs and to provide the needed field of view. Over the projected five year run of the survey we expect to obtain approximately 170 GB of data each night. For the data reduction we developed the Cure pipeline, to automatically find and calibrate the observed spectra, subtract the sky background, and detect and classify different types of sources. Cure employs rigorous statistical methods and complete pixel-level error propagation throughout the reduction process to ensure Poisson-limited performance and meaningful significance values. To automate the reduction of the whole dataset we implemented the Cure pipeline in the Astro-WISE framework. This integration provides for HETDEX a database backend with complete dependency tracking of the various reduction steps, automated checks, and a searchable interface to the detected sources and user management. It can be used to create various web interfaces for data access and quality control. Astro-WISE allows us to reduce the data from all the IFUs in parallel on a compute cluster. This cluster allows us to reduce the observed data in quasi real time and still have excess capacity for rerunning parts of the reduction. Finally, the Astro-WISE interface will be used to provide access to reduced data products to the general community.

  19. Invasive Scedosporium sternal osteomyelitis following lung transplant: Cured.

    PubMed

    Denton, E J; Smibert, O; Gooi, J; Morrissey, C O; Snell, G; McGiffin, D; Paraskeva, M

    2016-06-01

    Scedosporium is an important pathogen in cystic fibrosis (CF) and post-transplant but rarely causes invasive infection. Treatment remains challenging, particularly due to inherent resistance to multiple antifungal agents. We present a young man with CF who developed invasive sternal and rib infection 10-months following lung transplant. The infection has been clinically and radiologically cured with extensive surgery and triazole therapy. This case highlights the importance of adjunctive surgery in addition to prolonged triazole treatment to manage invasive Scedosporium infections in immunosuppressed patients.

  20. Developing the Manufacturing Process for Hylene MP Curing Agent

    SciTech Connect

    Eastwood, Eric

    2009-02-16

    This report details efforts to scale-up and re-establish the manufacturing process for the curing agent known as Hylene MP. First, small scale reactions were completed with varying conditions to determine key drivers for yielding high quality product. Once the optimum conditions were determined on the small scale, the scaled-up process conditions were determined. New equipment was incorporated into the manufacturing process to create a closed production system and improve chemical exposure controls and improve worker safety. A safe, efficient manufacturing process was developed to manufacture high quality Hylene MP in large quantities.

  1. Low toxicity aromatic diamine curing agents for adhesives

    SciTech Connect

    Dorsey, G.F.

    1993-08-24

    Increasing severity of regulations for handling of hazardous materials has led to formulation of adhesives with considerably lowered toxicities for use at the Oak Ridge Y-12 Plant. Fundamental was the development of Asilamine aromatic diamines, a family of liquid aromatic diamines useful as substitutes for methylenedianiline (MDA), a widely used adhesives curing agent. The use of Asilamine has allowed us to continue operations without dealing with expensive measures for regulation of MDA as a carcinogen promulgated by the Occupational Safety and Health Administration (OSHA).

  2. Resin flow and void formation in an autoclave cure cycle

    NASA Astrophysics Data System (ADS)

    Lionetto, Francesca; Lucia, Massimo; Dell'Anna, Riccardo; Maffezzoli, Alfonso

    2016-05-01

    A finite element (FE) model able to evaluate both the evolution of resin flow, degree of reaction and void formation during autoclave cure cycles was developed. The model was implemented using a commercial epoxy matrix widely used in aeronautic field. The FE model also included a kinetic and rheological model whose input parameters were experimentally determined by Differential Scanning Calorimetry and rheological analysis. The FE model was able to predict the evolution of degree of reaction with very good agreement with the experimental data. Moreover, the predicted resin losses were lower than 3% of the overall composite resin content.

  3. Demonstration of Mer-Cure Technology for Enhanced Mercury Control

    SciTech Connect

    John Marion; Dave O'Neill; Kevin Taugher; Shin Kang; Mark Johnson; Gerald Pargac; Jane Luedecke; Randy Gardiner; Mike Silvertooth; Jim Hicks; Carl Edberg; Ray Cournoyer; Stanley Bohdanowicz; Ken Peterson; Kurt Johnson; Steve Benson; Richard Schulz; Don McCollor; Mike Wuitshick

    2008-06-01

    Alstom Power Inc. has completed a DOE/NETL-sponsored program (under DOE Cooperative Agreement No. De-FC26-07NT42776) to demonstrate Mer-Cure{trademark}, one of Alstom's mercury control technologies for coal-fired boilers. The Mer-Cure{trademark}system utilizes a small amount of Mer-Clean{trademark} sorbent that is injected into the flue gas stream for oxidation and adsorption of gaseous mercury. Mer-Clean{trademark} sorbents are carbon-based and prepared with chemical additives that promote oxidation and capture of mercury. The Mer-Cure{trademark} system is unique in that the sorbent is injected into an environment where the mercury capture kinetics is accelerated. The full-scale demonstration program originally included test campaigns at two host sites: LCRA's 480-MW{sub e} Fayette Unit No.3 and Reliant Energy's 190-MW{sub e} Shawville Unit No.3. The only demonstration tests actually done were the short-term tests at LCRA due to budget constraints. This report gives a summary of the demonstration testing at Fayette Unit No.3. The goals for this Mercury Round 3 program, established by DOE/NETL under the original solicitation, were to reduce the uncontrolled mercury emissions by 90% at a cost significantly less than 50% of the previous target of $60,000/lb mercury removed. The results indicated that Mer-Cure{trademark} technology could achieve mercury removal of 90% based on uncontrolled stack emissions. The estimated costs for 90% mercury control, at a sorbent cost of $0.75 to $2.00/lb respectively, were $13,400 to $18,700/lb Hg removed. In summary, the results from demonstration testing show that the goals established by DOE/NETL were met during this test program. The goal of 90% mercury reduction was achieved. Estimated mercury removal costs were 69-78% lower than the benchmark of $60,000/lb mercury removed, significantly less than 50% of the baseline removal cost.

  4. Solid Rocket Fuel Constitutive Theory and Polymer Cure

    NASA Technical Reports Server (NTRS)

    Ream, Robert

    2006-01-01

    Solid Rocket Fuel is a complex composite material for which no general constitutive theory, based on first principles, has been developed. One of the principles such a relation would depend on is the morphology of the binder. A theory of polymer curing is required to determine this morphology. During work on such a theory an algorithm was developed for counting the number of ways a polymer chain could assemble. The methods used to develop and check this algorithm led to an analytic solution to the problem. This solution is used in a probability distribution function which characterizes the morphology of the polymer.

  5. Towards an HIV-1 cure: measuring the latent reservoir.

    PubMed

    Bruner, Katherine M; Hosmane, Nina N; Siliciano, Robert F

    2015-04-01

    The latent reservoir (LR) of HIV-1 in resting memory CD4(+) T cells serves as a major barrier to curing HIV-1 infection. While many PCR- and culture-based assays have been used to measure the size of the LR, correlation between results of different assays is poor and recent studies indicate that no available assay provides an accurate measurement of reservoir size. The discrepancies between assays are a hurdle to clinical trials that aim to measure the efficacy of HIV-1 eradication strategies. Here we describe the advantages and disadvantages of various approaches to measuring the LR.

  6. Spontaneous recovery of bone mass after cure of endogenous hypercortisolism.

    PubMed

    Randazzo, Maria Elena; Grossrubatscher, Erika; Dalino Ciaramella, Paolo; Vanzulli, Angelo; Loli, Paola

    2012-06-01

    Patients with Cushing's syndrome (CS) develop osteopenia-osteoporosis. The present study evaluates the recovery of bone mass within 2 years after remission of hypercortisolism and in long term follow up, an issue rarely addressed. Twenty patients (6M, 14F, 3 post-menopausal, 15-64 years old), 15 with Cushing's disease, 2 with ectopic ACTH syndrome, 3 with ACTH-independent CS were studied. BMD, T and Z scores at lumbar spine and proximal femur were assessed by dual-energy X-ray absorptiometry before and 7-33 months after treatment of hypercortisolism. Five patients were treated with bisphosphonates. Four patients had hypogonadism and 4 GH-deficiency. At baseline all patients showed osteopenia/osteoporosis and the spine appeared more damaged than the femur; femur BMD was positively related with body mass index (BMI). No correlations were observed between spine and femur bone parameters and duration of disease or severity of hypercortisolism. Bone parameters did not differ in patients with or without GH or other pituitary deficiencies. After cure of hypercortisolism a significant improvement in spine BMD, Z and T scores and in femur Z and T scores was observed with normalization in 3 patients; there was no significant difference in percent improvement between femur and spine. The increase in bone parameters at spine and femur was independent from values at baseline. The percent increase in spine T and Z scores was positively related with time elapsed since cure. Bisphosphonates did not influence the recovery of bone mineralization. In long term follow up, after a median period of 7 years a further improvement in bone density was observed in 100% of patients at spine and in 9/11 at femur, although 8/11 patients still had femoral and/or vertebral T score in the range of osteopenia/osteoporosis. Spontaneous improvement of osteoporosis after cure of hypercortisolism occurs both at spine and femur, is independent from basal conditions and not affected by bisphosphonates

  7. Ex vivo gene therapy cures a blistering skin disease.

    PubMed

    Featherstone, Carol; Uitto, Jouni

    2007-06-01

    A recent publication that describes gene therapy treatment of a patient with an inherited blistering skin disease, epidermolysis bullosa, demonstrates for the first time that gene therapy can cure a disease of solid tissue. The treatment relies on ex vivo transduction of autologous epidermal stem cells with a normal copy of the defective gene, followed by reconstitution of the patient's skin with epithelial sheets that are grown from these genetically corrected cells. This approach holds promise for treatment not only of inherited disorders of the skin but also of other solid tissues that are becoming amenable to tissue engineering.

  8. Status of the UV Cure Powder Coating Demonstration Project

    DTIC Science & Technology

    2012-01-01

    Infra-Tea radiatlo n~ 60 - 65% 6 . 6.5 kW UV-Cure Technology  We use a Gallium doped lamp: DISTRIBUTION A. Approved for public release...2010 (Cont.)  Low copper alloys (6000, 3000 series) not a problem High copper alloys scavenge free radicals at surface Determined that certain...resistance tests  Neutral salt fog (MIL-PRF-23377J, ASTM B117)  UVCPC over Zn Phosphate 4130 steel, 2000 hrs (Pass)  UVCPC over Alodine 1600

  9. Effect of vacuum packaging on growth of Clostridium botulinum and Staphylococcus aureus in cured meats.

    PubMed

    Christiansen, L N; Foster, E M

    1965-11-01

    Incrimination of vacuum-packaged smoked fish in outbreaks of botulism has raised questions about the safety of this process in comparison with other methods of packaging foods. It has been suggested, for example, that Clostridium botulinum may grow better in a vacuum-packaged product than in one that is packaged without vacuum. To evaluate this possibility, sliced bologna was inoculated with spores of C. botulinum type A, packaged in transparent plastic film with and without vacuum, and stored at temperatures within the growth range of the organism. There was no detectable difference in the rate of toxin development in the two types of packages. In contrast, vacuum packaging markedly inhibited the growth of Staphylococcus aureus on sliced ham. The results indicate that vacuum packaging has little if any effect on the ability of C. botulinum to grow in cured meats, but it may reduce the likelihood of staphylococcal food poisoning.

  10. Evaluation of Fosthiazate for Management of Meloidogyne javanica in Florida Flue-cured Tobacco

    PubMed Central

    Rich, J. R.; Dunn, R. A.; Thomas, W. D.; Breman, J. W.; Tervola, R. S.

    1994-01-01

    One grower trial and two experiment station tests were conducted to evaluate a new nematicide, fosthiazate, for management of Meloidogyne javanica in Florida flue-cured tobacco. Fosthiazate was applied broadcast and incorporated at rates ranging from 21 to 84 g/100 m² and compared with 1,3-dichloropropene at 240 and 460 ml/100 m² and fenamiphos at 67 g/100 m². All fosthiazate treatments increased tobacco yields and reduced root galling. Application of 1,3-D provided the highest tobacco yields and greatest reductions in root galling. The fenamiphos treatment outperformed all fosthiazate treatments in tobacco yield and root gall reduction. Fosthiazate may therefore have limited utility compared with 1,3-D and fenamiphos as a nematicide for tobacco in peninsular Florida. PMID:19279951

  11. Synergistic effect of graphene-oxide-doping and microwave-curing on mechanical strength of cement

    NASA Astrophysics Data System (ADS)

    Qin, Hao; Wei, Wei; Hang Hu, Yun

    2017-04-01

    In this communication, efficient reinforcement of cement matrix was obtained by graphene-oxide (GO) doping and curing treatments. The compressive strength of plain cement is 14.3±0.2 MPa. When the cement contained 0.5 wt% GO, its strength reached 19.4±0.9 MPa. The strength can be further enhanced by curing, which follows the sequence: Microwave-cured GO-cement > Microwave and water-cured GO-cement > Water-cured GO-cement > GO-cement without curing. The highest compressive strength (32.4±0.7 MPa), which was achieved by combining GO-doping and microwave curing, is 126.6±8.1% higher than that without GO-doping and microwave curing. This demonstrates a synergistic effect of GO doping and microwave-curing on the strength of cement composite materials. Furthermore, X-ray diffraction (XRD), Fourier transform Infrared Spectroscopy (FTIR), and field emission scanning electron microscope (FESEM) characterizations revealed that the combination of GO doping and microwave-curing remarkably accelerated cement hydration, leading to the regular and compact structure and thus a high compressive strength. This work provides a new way to improve the mechanical properties of cement composites.

  12. Effect of drying processes and curing time of chitosan-lysine semi-IPN beads on chlorpheniramine maleate delivery.

    PubMed

    Kumari, K; Kundu, P P

    2009-02-01

    Beads of semi-interpenetrating polymer network (semi-IPN) have been synthesized from chitosan and lysine with varying amounts of glutaraldehyde solution used as a cross-linker. The cross-linked beads are dried by different drying processes such as air-drying, oven-drying and freeze-drying. These semi-IPNs are characterized under a scanning electron microscope (SEM). Swelling studies of these beads are carried out in different pH (2.0 and 7.4) solutions. The effect of concentration of cross-linking agent and curing period on the swelling as well as on the drug release is analysed. The results indicate that the size of matrix depend on the curing time of beads, concentration of glutaraldehyde and technique of drying. The freeze-dried beads exhibit a relatively higher percentage of swelling in the range of 66-89% as compared to oven-dried beads (53-74%) and air-dried beads (39-61%). The drug loaded beads which are cured for different time intervals followed by drying are tested for in-vitro release of chlorpheniramine maleate (CPM) drug. The rate of drug release from freeze-dried beads is much faster than that from the oven-dried and air-dried beads.

  13. Integrated Pest Management Practices Reduce Insecticide Applications, Preserve Beneficial Insects, and Decrease Pesticide Residues in Flue-Cured Tobacco Production.

    PubMed

    Slone, Jeremy D; Burrack, Hannah J

    2016-09-22

    Integrated pest management (IPM) recommendations, including scouting and economic thresholds (ETs), are available for North Carolina flue-cured tobacco growers, although ETs for key pests have not been updated in several decades. Moreover, reported IPM adoption rates by flue-cured tobacco growers remain low, at < 40%, according to NC cooperative extension surveys conducted during the last four years. Previous research has suggested that timing insecticide treatments using currently available ETs can reduce the average number of applications to two or fewer per season. We conducted field-scale trials at nine commercial tobacco farms, three in 2104 and six in 2015, to quantify inputs associated with current scouting recommendations, to determine if current ETs were able to reduce insecticide applications as compared to grower standard practices, and to assess the impacts of reduced insecticide applications on end of season yield and pesticide residues. Two fields were identified at each farm and were scouted weekly for insects. One field was only treated with insecticides if pests reached ET (IPM), while the other field was managed per grower discretion (Grower Standard). IPM fields received an average of two fewer insecticide applications without compromising yield. More insecticide applications resulted in higher pesticide residues in cured leaf samples from Grower Standard fields than those from IPM fields. Reductions in insecticides and management intensity also resulted in larger beneficial insect populations in IPM fields.

  14. Effects of Different Light Curing Units/Modes on the Microleakage of Flowable Composite Resins

    PubMed Central

    Yazici, A. Ruya; Celik, Cigdem; Dayangac, Berrin; Ozgunaltay, Gul

    2008-01-01

    Objectives The aim of this in vitro study was to evaluate the influence of different light curing units and modes on microleakage of flowable composite resins. Methods Eighty Class V cavities were prepared in buccal and lingual surfaces of 40 extracted human premolars with cervical wall located in dentin and the occlusal wall in enamel. These teeth were randomly assigned into two groups (n=20) and restored with different flowable composites; Group I: Esthet-X Flow, Group II: Grandio Flow. Each group was randomly divided into four subgroups; while the samples of the first subgroup were polymerized with conventional Halogen light, the rest of them were polymerized with different curing modes of Light Emitting Diode (LED). The second subgroup was polymerized with fast-curing; the third subgroup with pulse-curing and those of the fourth subgroup with step-curing modes of LED. After the samples were thermocycled and immersed in dye, they were longitudinally sectioned. Dye penetration was assessed under a stereomicroscope. Data were analyzed by Kruskal-Wallis and Mann-Whitney U tests. Results None of the restorations showed leakage on enamel margins. On dentin margins no significant differences were observed between flowable composite resins polymerized with halogen light (P>.05). While step curing mode of LED presented significant differences between the resins, the difference was insignificant when fast-curing and pulse-curing mode of LED were used. No statistically significant differences were observed between curing units for Esthet-X Flow samples. For Grandio Flow samples, only step-curing mode of LED caused statistically higher leakage scores than halogen and other curing modes of LED (P<.05). Conclusions The effect of curing units’ type and curing mode on flowable composite resin leakage might be material-dependent. PMID:19212529

  15. The Scientific Quest for Lasting Youth: Prospects for Curing Aging

    PubMed Central

    2014-01-01

    Abstract People have always sought eternal life and everlasting youth. Recent technological breakthroughs and our growing understanding of aging have given strength to the idea that a cure for human aging can eventually be developed. As such, it is crucial to debate the long-term goals and potential impact of the field. Here, I discuss the scientific prospect of eradicating human aging. I argue that curing aging is scientifically possible and not even the most challenging enterprise in the biosciences. Developing the means to abolish aging is also an ethical endeavor because the goal of biomedical research is to allow people to be as healthy as possible for as long as possible. There is no evidence, however, that we are near to developing the technologies permitting radical life extension. One major difficulty in aging research is the time and costs it takes to do experiments and test interventions. I argue that unraveling the functioning of the genome and developing predictive computer models of human biology and disease are essential to increase the accuracy of medical interventions, including in the context of life extension, and exponential growth in informatics and genomics capacity might lead to rapid progress. Nonetheless, developing the tools for significantly modifying human biology is crucial to intervening in a complex process like aging. Yet in spite of advances in areas like regenerative medicine and gene therapy, the development of clinical applications has been slow and this remains a key hurdle for achieving radical life extension in the foreseeable future. PMID:25132068

  16. Blue light curing units--a dermatological hazard?

    PubMed

    Chadwick, R G; Traynor, N; Moseley, H; Gibbs, N

    1994-01-08

    The setting reactions of a large number of dental materials are activated upon exposure to visible blue light emitted from a curing unit. Although the wavelength (lambda) from such devices is principally in the visible spectrum (lambda > 400 nm) a small amount of ultraviolet radiation (UV) is also present. Little attention has been paid to the consequences of such exposure upon the skin of dental surgeons' fingers. This investigation studied the level of UVA I (lambda = 340-400 nm) emitted by three commonly used polymerisation sources and assessed the level of protection afforded by six brands of surgical glove. The integrated irradiances of the Translux, Topaz T100 and Heliomat units in the UVA I range were 15861, 3611 and 305 mW/m2 respectively. For all gloves the mean % transmission, at lambda = 400 nm, was less than 4% with the exception of one brand where, in the stretched state, the level of transmission was 7%. It is concluded that the risk of initiating adverse dermatological consequences as a result of exposure to UVA I, emitted by light polymerisation units, is minimal in normal usage. The combined effects of exposure to radiation of this type and contamination of the fingers with quantities of irritant chemicals, such as found in many dental materials, are unknown. Due to the ability of the gloves to shield the skin from both chemicals and UVA I it is recommended that gloves are routinely worn for all light curing procedures.

  17. Physicochemical and sensory properties of irradiated dry-cured ham

    NASA Astrophysics Data System (ADS)

    Jin, Sang-Keun; Kim, Chul-Wook; Chung, Ki-Hwa; Jo, Kwang-Keun; Jeong, Jin-Yeon; Hur, In-Chul; Jung, Eun-Young; Joo, Seon-Tea; Yang, Han-Sul

    2012-02-01

    To determine the effect of different irradiation doses on ready-to-eat (RTE) dry-cured shoulder hams, physicochemical and sensory attributes were analyzed during 8 weeks of refrigerated storage. The results show that irradiation reduced the redness value and increased the 2-thiobarbituric acid-reactive substance (TBARS) value as well as the irradiation aroma during storage. However, ham samples irradiated with 2.5 and 5.0 kGy did not show significant changes in lightness values compared to the control sample during 8 weeks of storage. TBARS values were lower in the sample irradiated with 2.5 kGy than in the other irradiated samples. The total plate counts of the 5.0 kGy-irradiated samples were not measured after 0 weeks. Sensory panels found that the 2.5- and 5.0 kGy-irradiated samples had better overall acceptability scores than the other irradiated samples. It was concluded that treatments with lower levels of irradiation (≤5.0 kGy) can enhance the microbial safety and sensory acceptance of dry-cured shoulder hams.

  18. Curanderismo and Latino Views of Disease and Curing

    PubMed Central

    Maduro, Renaldo

    1983-01-01

    Curanderismo is a diverse folk healing system of Latin America. Eight major philosophical premises underlie a coherent curing world view of Latino patients: disease or illness may follow (1) strong emotional states (such as rage, fear, envy or mourning of painful loss) or (2) being out of balance or harmony with one's environment; (3) a patient is often the innocent victim of malevolent forces; (4) the soul may become separated from the body (loss of soul); (5) cure requires the participation of the entire family; (6) the natural world is not always distinguishable from the supernatural; (7) sickness often serves the social function, through increased attention and rallying of the family around a patient, of reestablishing a sense of belonging (resocialization) and (8) Latinos respond better to an open interaction with their healer. These nuclear ideas or attitudes about health, illness and care are culturally patterned and are both conscious and unconscious (implicit). Moreover, expectations of the nature of the patient-healer relationship have implications for medical practice in general and psychotherapy in particular. PMID:6364577

  19. Evaluation of polymerization of light-curing hybrid composite resins.

    PubMed

    Kwon, Yong Hoon; Jeon, Geon-Hoo; Jang, Chang-Min; Seol, Hyo-Joung; Kim, Hyung-Il

    2006-01-01

    The quality of polymerization of hybrid composite resins was tested to explore their feasibility for dental restorations. For this, microhardness, polymerization shrinkage, the coefficient of thermal expansion, and surface morphology were evaluated during or after light curing in conjunction with the thermocycling process. Each product had different microhardness values. The repeated thermal stimulus has no specific effect on the change of microhardness. The difference of microhardness between the thermocycled specimens and specimens stored only in distilled water was minor. The measured microhardness had a linear correlation with the filler content (vol %) of the tested specimens. The polymerization shrinkage had rapidly increased only during the light curing, and then it reached a plateau. Among the specimens, Z250 showed the least amount of shrinkage for all tested thicknesses. Regardless of the product, the shrinkage values increased as the specimens became thick. The coefficient of thermal expansion of the control specimens ranged between 42 and 55 microm/degrees C in the temperature range of 30-80 degrees C. The coefficient showed an inverse correlation with the filler content. Through the thermocycling process, Palfique Estelite showed randomly propagating cracks on the surface. Larger fillers showed a more apparent detachment than the smaller fillers.

  20. Targeting the Brain Reservoirs: Toward an HIV Cure

    PubMed Central

    Marban, Céline; Forouzanfar, Faezeh; Ait-Ammar, Amina; Fahmi, Faiza; El Mekdad, Hala; Daouad, Fadoua; Rohr, Olivier; Schwartz, Christian

    2016-01-01

    One of the top research priorities of the international AIDS society by the action “Towards an HIV Cure” is the purge or the decrease of the pool of all latently infected cells. This strategy is based on reactivation of latently reservoirs (the shock) followed by an intensifying combination antiretroviral therapy (cART) to kill them (the kill). The central nervous system (CNS) has potential latently infected cells, i.e., perivascular macrophages, microglial cells, and astrocytes that will need to be eliminated. However, the CNS has several characteristics that may preclude the achievement of a cure. In this review, we discuss several limitations to the eradication of brain reservoirs and how we could circumvent these limitations by making it efforts in four directions: (i) designing efficient latency-reversal agents for CNS-cell types, (ii) improving cART by targeting HIV transcription, (iii) improving delivery of HIV drugs in the CNS and in the CNS-cell types, and (iv) developing therapeutic immunization. As a prerequisite to these efforts, we also believe that a better comprehension of molecular mechanisms involved in establishment and persistence of HIV latency in brain reservoirs are essential to design new molecules for strategies aiming to achieve a cure for instance the “shock and kill” strategy. PMID:27746784

  1. Why have we failed to cure Alzheimer's disease?

    PubMed

    Korczyn, Amos D

    2012-01-01

    There is widespread recognition in the urgency to understand the causes and mechanisms of senile dementia. Attempts to find cures for Alzheimer's disease (AD) have, however, failed so far, in spite of enormous investments, intellectual and financial. We therefore have to reconsider the problem from new angles. AD is regarded as a disease because of its clinical manifestations and underlying pathology. However, this combination does not define a disease but rather a syndrome, just like hepatic cirrhosis in which liver pathology causes metabolic changes, but which can result from many different etiologies. It is unlikely that attacking a downstream phenomenon, like apoptosis or amyloid-β accumulation, can cure AD, or prevent the progression of the disease. It is probable that senile dementia is the result of a combination of several processes, working differently in each person. Epidemiological studies have identified many risk factors for "senile dementia of the Alzheimer type", some genetic but most environmental and therefore modifiable. Thus, a concerted action to fight the dementia epidemic must be made by aggressive action against its risk factors, and this battle must begin in midlife, not in old age.

  2. In situ measurement of cure, latex coalescence and end-use properties in thin film coatings using frequency dependent impedance sensing

    SciTech Connect

    Kranbuehl, D.E.

    1993-12-31

    As in situ frequency dependent impedance sensor (FDIMS) has been successfully used to monitor cure and buildup in end use properties of coatings. The planar microsensor is able to make continuous uninterrupted measurements of the resin while it cures as a coating with only one side exposed. It is able to monitor reaction onset, reaction rate, viscosity, buildup in hardness, reaction completion and related processes such as latex coalescence and evolution of volatiles. Effects of storage, temperature, humidity, thickness and variations in composition on the cure process can also be detected. The sensor monitors the changes in the rate of translational motion of ions and rotational motion of dipoles through frequency dependent complex impedance measurements. In this report the ability of the sensor to monitor the effects of the environmental conditions such as temperature and humidity, as well as coating formulation differences due to pigments, on the cure process is reported. The ability of the FDIMS sensor to monitor the extent to which a second coating can soften the initial coating will be discussed. The ability of the FDIMS sensors to monitor the extent to which water can diffuse into the coating will also be described.

  3. Perceiving one’s heart condition to be cured following hospitalization for acute coronary syndromes: implications for patient-provider communication

    PubMed Central

    Waring, Molly E.; McManus, David D.; Lemon, Stephenie C.; Gore, Joel M.; Anatchkova, Milena D.; McManus, Richard H.; Ash, Arlene S.; Goldberg, Robert J.; Kiefe, Catarina I.; Saczynski, Jane S.

    2015-01-01

    Objective We examined the proportion of patients perceiving their heart condition to be cured following hospitalization for ACS and identified characteristics associated with these perceptions. Methods We conducted a prospective cohort study of adults hospitalized with ACS (N=396). Patient interviews during hospitalization and one week post-discharge provided demographic and psychosocial characteristics. Medical records provided clinical characteristics. At one week, patients who rated “My heart condition is cured” as “definitely true” or “mostly true” were considered to perceive their heart condition cured. Results Participants were aged 60.7 (SD:11.0) years, 26.5% female, and 89.0% non-Hispanic white; 16.7% had unstable angina, 59.6% NSTEMI, and 23.7% STEMI. One week post-discharge, 30.3% perceived their heart condition to be cured. Characteristics associated with cure perceptions were older age (OR=2.2; 95% CI: 1.2–4.0 for ≥65 years vs <55 years), male sex (OR=2.4; 95%CI: 1.3–4.2), history of hypertension (OR=1.8; 95%CI: 1.1–3.1), history of stroke (OR=4.2; 95%CI: 1.1–16.7), no history of CHD (OR=2.8; 95%CI: 1.6–4.9), and receipt of CABG during hospitalization (OR=4.8, 95%CI: 1.9–12.0 vs medical management). Conclusion One week post-discharge, 3 in 10 patients perceived their heart condition to be cured. Practice Implications Conversations with patients should frame ACS as a chronic disease and dispel cure perceptions. PMID:26519237

  4. Effects of Amine and Anhydride Curing Agents on the VARTM Matrix Processing Properties

    NASA Technical Reports Server (NTRS)

    Grimsley, Brian W.; Hubert, Pascal; Song, Xiaolan; Cano, Roberto J.; Loos, Alfred C.; Pipes, R. Byron

    2002-01-01

    To ensure successful application of composite structure for aerospace vehicles, it is necessary to develop material systems that meet a variety of requirements. The industry has recently developed a number of low-viscosity epoxy resins to meet the processing requirements associated with vacuum assisted resin transfer molding (VARTM) of aerospace components. The curing kinetics and viscosity of two of these resins, an amine-cured epoxy system, Applied Poleramic, Inc. VR-56-4 1, and an anhydride-cured epoxy system, A.T.A.R.D. Laboratories SI-ZG-5A, have been characterized for application in the VARTM process. Simulations were carried out using the process model, COMPRO, to examine heat transfer, curing kinetics and viscosity for different panel thicknesses and cure cycles. Results of these simulations indicate that the two resins have significantly different curing behaviors and flow characteristics.

  5. Nitrite, nitrite alternatives, and the control of Clostridium botulinum in cured meats.

    PubMed

    Pierson, M D; Smoot, L A

    1982-01-01

    Historically, nitrite has been a component of meat-curing additives for several centuries. In recent years the safety of nitrite as an additive in cured meats has been questioned mainly because of the possible formation of carcinogenic nitrosamines. Nitrite has many important functions in meat curing including its role in color development, flavor, antioxidant properties, and antimicrobial activity. The inhibition of Clostridium botulinum growth and toxin production is an especially important antimicrobial property of nitrite. This review discusses the effects of processing, curing ingredients (especially nitrite), and storage of cured meats in relation to the control of C. botulinum. If nitrite is eliminated from cured meats or the level of usage decreased, then alternatives for the antibotulinal function of nitrite need to be considered. Several potential alternatives including sorbates, parabens, and biological acidulants are discussed.

  6. Dynamic cure measurement of dental polymer composites using optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Tomlins, Peter H.; Palin, Will M.; Shortall, Adrian C.

    2008-02-01

    Dental amalgam is being increasingly replaced by Light-activated resin-based dental composites. However, these materials are limited by inefficient setting reactions as a function of depth, constraining the maximum extent of cure and reducing biocompatibility. In this paper we demonstrate a novel metrological tool for dynamic monitoring of refractive index and thickness change through curing resins using spectral-domain optical coherence tomography. We present real-time measurements from pre- to post-cure of a series of un-filled bisphenol-A diglycidyl ether dimethacrylate (bisGMA) and triethylene glycol dimethacrylate (TEGDMA) resins with different inhibitor concentrations. Our results demonstrate that refractive index measurements are sensitive to the extent of cure of such resins and that the inhibitor concentration strongly affects the cure dynamics and final extent of cure.

  7. ENGINEERED INTERFACE CHEMISTRY TO IMPROVE THE MECHANICAL PROPERTIES OF CARBON FIBER COMPOSITES CURED BY ELECTRON BEAM

    SciTech Connect

    Vautard, Frederic; Grappe, Hippolyte A.; Ozcan, Soydan

    2014-01-01

    A reactive sizing was designed to achieve high levels of interfacial adhesion and mechanical properties with a carbon fiber-acrylate system cured by electron beam (EB). The sizing was made of a partially cured epoxy sizing with a high density of pendant functional groups (acrylate functionality) able to generate a covalent bonding with the matrix. The interlaminar shear strength was clearly improved from 61 MPa to 81 MPa (+ 33 %) without any post-processing, reaching a similar value to the one obtained with the same system cured by a thermal treatment. Observation of the fracture profiles clearly highlighted a change in the fracture mechanism from a purely adhesive failure to a cohesive failure. Such improvements of the mechanical properties of carbon fiber composites cured by EB, without any post-cure, have not been reported previously to the best of our knowledge. This constitutes a breakthrough for the industrial development of composites EB curing.

  8. Thermal analysis of bulk filled composite resin polymerization using various light curing modes according to the curing depth and approximation to the cavity wall

    PubMed Central

    CHANG, Hoon-Sang; CHO, Kyu-Jeong; PARK, Su-Jung; LEE, Bin-Na; HWANG, Yun-Chan; OH, Won-Mann; HWANG, In-Nam

    2013-01-01

    Objective The purpose of this study was to investigate the polymerization temperature of a bulk filled composite resin light-activated with various light curing modes using infrared thermography according to the curing depth and approximation to the cavity wall. Material and Methods Composite resin (AeliteFlo, Bisco, Schaumburg, IL, USA) was inserted into a Class II cavity prepared in the Teflon blocks and was cured with a LED light curing unit (Dr's Light, GoodDoctors Co., Seoul, Korea) using various light curing modes for 20 s. Polymerization temperature was measured with an infrared thermographic camera (Thermovision 900 SW/TE, Agema Infra-red Systems AB, Danderyd, Sweden) for 40 s at measurement spots adjacent to the cavity wall and in the middle of the cavity from the surface to a 4 mm depth. Data were analyzed according to the light curing modes with one-way ANOVA, and according to curing depth and approximation to the cavity wall with two-way ANOVA. Results The peak polymerization temperature of the composite resin was not affected by the light curing modes. According to the curing depth, the peak polymerization temperature at the depth of 1 mm to 3 mm was significantly higher than that at the depth of 4 mm, and on the surface. The peak polymerization temperature of the spots in the middle of the cavity was higher than that measured in spots adjacent to the cavity wall. Conclusion In the photopolymerization of the composite resin, the temperature was higher in the middle of the cavity compared to the outer surface or at the internal walls of the prepared cavity. PMID:24037066

  9. Investigation of Residual Stresses in a Hot Cured Glass Fibre Reinforced Epoxy Resin Composite

    DTIC Science & Technology

    1982-01-01

    to establish confidence in its use. Little work has been reported on the magnitudes of residual curing stresses and their effect on the performance...premature failure if the residual and service stresses are additive. Fbr accurate design work it is therefore essential to take residual curing stresses...used to evaluate the residual curing stresses in a liminated plate is given in Reference 2. The computer code developed in Reference 3 was used in this

  10. Influence of physical parameters on residual stresses of polymer composites during the cure process

    NASA Astrophysics Data System (ADS)

    Wang, Hui; Feng, Jiemin; Guo, Zhansheng; Hu, Hongjiu; Zhang, Junqian

    2011-11-01

    A developed process model including the effects of chemical and thermal strains and the cure related elastic material behavior is established in order to simulate the cure process before cooling stage more realistically. A three-dimensional finite element method is used to analyze the effect of the curing related parameters on residual stresses in the cure progress of polymer composites. The obtained results show that the density, the specific heat, the thermal conductivity and the anisotropic chemical shrinkage have different influences on the final residual stresses before cooling stage.

  11. Influence of physical parameters on residual stresses of polymer composites during the cure process

    NASA Astrophysics Data System (ADS)

    Wang, Hui; Feng, Jiemin; Guo, Zhansheng; Hu, Hongjiu; Zhang, Junqian

    2012-04-01

    A developed process model including the effects of chemical and thermal strains and the cure related elastic material behavior is established in order to simulate the cure process before cooling stage more realistically. A three-dimensional finite element method is used to analyze the effect of the curing related parameters on residual stresses in the cure progress of polymer composites. The obtained results show that the density, the specific heat, the thermal conductivity and the anisotropic chemical shrinkage have different influences on the final residual stresses before cooling stage.

  12. Hard and soft computing models of composite curing process looking toward monitoring and control

    NASA Astrophysics Data System (ADS)

    Rubino, F.; Carlone, P.; Aleksendrić, D.; Ćirović, V.; Sorrentino, L.; Bellini, C.

    2016-10-01

    The curing process of thermosetting resins plays a key role on the final quality of the composite material components. Soft computing techniques proved to be an efficient method to control and optimize the curing process, replacing the conventional experimental and numerical approaches. In this paper artificial neural network (ANN) and fuzzy logic control (FLC) were implemented together to predict and control the temperature and degree of cure profile during the autoclave curing process. The obtained outcomes proved the capability of ANNs and FLC with respect to the hard computing methods.

  13. CARBON FIBRE COMPOSITE MATERIALS PRODUCED BY GAMMA RADIATION INDUCED CURING OF EPOXY RESINS

    SciTech Connect

    Dispenza, C.; Spadaro, G.; Alessi, S.

    2008-08-28

    It is well known that ionizing radiation can initiate polymerization of suitable monomers for many applications. In this work an epoxy difunctional monomer has been used as matrix of a carbon fibre composite in order to produce materials through gamma radiation, for aerospace and advanced automotive applications. Radiation curing has been performed at different absorbed doses and, as comparison, also thermal curing of the same monomer formulations has been done. Furthermore some irradiated samples have been also subjected to a post irradiation thermal curing in order to complete the polymerization reactions. The properties of the cured materials have been studied by moisture absorption isotherms, dynamic mechanical thermal analysis and mechanical flexural tests.

  14. Low-temperature curing of a nitrile-epoxy adhesive. Final report

    SciTech Connect

    Tira, J.S.

    1981-04-01

    Adhesive strength and glass transition temperature were correlated with cure times at 85/sup 0/C and above. The effect of moisture on adhesive cure and strength was tested. With a 3-hour cure at 85/sup 0/C, lap shear strength met specification requirements. The adhesive was found to absorb moisture with time, especially if one or both polyethylene covers are removed. Placing the adhesive in a desiccator for 30 minutes produced excellent room temperature shear strengths. Preconditioning (removal of moisture) is critical for elevated temperature cures.

  15. Dielectric cure monitoring of the 55A filament wound case resin

    NASA Technical Reports Server (NTRS)

    Mcnutt, R. C.

    1986-01-01

    Studies were conducted to correlate data from dielectric cure monitoring of 55A filament would case resins using the Micromet System II with differential scanning calorimetry and resin strength tests. Strength tests for resin bonding at various time intervals and DSC are standard accepted techniques for monitoriong resin cure cycles. They are time consuming, destructive, and non-continuous. The Micromet System II will yield reliable information on degree of cure and other parameters, which should allow better quality control on filament wound case resin cure.

  16. Terahertz time-domain spectroscopy for monitoring the curing of dental composites

    PubMed Central

    Schwerdtfeger, Michael; Lippert, Sina; Koch, Martin; Berg, Andreas; Katletz, Stefan; Wiesauer, Karin

    2012-01-01

    We apply terahertz (THz) time-domain spectroscopy for monitoring the curing process of three different light-curing dental composites. Exact knowledge of the sample thickness is required for a precise determination of the THz dielectric parameters, as the materials exhibit shrinkage when they are cured. We find very small but significant changes of the THz refractive index and absorption coefficient during stepwise light exposure. The changes in the refractive index are correlated with changes in the density of the materials. Furthermore, the refractive index and the sample thickness are found to give the most reliable result for monitoring the curing process of the dental composites. PMID:23162722

  17. Characterization-curing-property studies of HBRF 55A resin formulations

    NASA Technical Reports Server (NTRS)

    Pearce, E. M.; Mijovic, J.

    1985-01-01

    Characterization curing property investigations on HBRF 55A resin formulations are reported. The initial studies on as received cured samples cut from a full-size FWC are reviewed. Inadequacies of as-received and aged samples are pointed out and additional electron microscopic evidence is offered. Characterization of as-received ingredients of HBRF 55A formulation is described. Specifically, Epon 826, Epon 828, EpiRez 5022, RD-2 and various amines, including Tonox and Tonox 60.40, were characterized. Cure kinetics of various formulations are investigated. Changes in physical/thermal properties (viscosity, specific heat, thermal conductivity and density) during cure are described.

  18. Study on catalysis effect of TEPB on the curing reaction of HTPB binder system

    NASA Astrophysics Data System (ADS)

    Chang, S. J.; Tang, J.; Liu, X.; Yan, W.

    2016-07-01

    The catalysis effect of tri (exhoxyphenyl) bismuthine (TEPB) on the curing reaction of HTPB binder system was studied by using DSC method. The curing peak temperatures of the catalyst systems were measured to calculate kinetic parameters by using Kissinger and Crane methods, respectively. Two curing reaction kinetic equations were established. The results show that TEPB has high catalytic activity and can decrease the curing temperature of HTPB binder system, down to 35 °C, in which the optimum volume of TEPB is 0.5% of HTPB binder system.

  19. Evaluation of light curing units used for polymerization of orthodontic bonding agents.

    PubMed

    Oyama, Nanako; Komori, Akira; Nakahara, Rizako

    2004-12-01

    This study evaluated the light intensity of various light curing units, the effect of distance of the light guide, and the validity of a tapered light guide. Light curing units tested included (1) four blue light-emitting diode curing units, Lux-O-Max, LEDemetronl, Ortholux LED, and The Cure; (2) two tungsten-quartz halogen curing units, Optilux 501 and Co-bee; and (3) one plasma arc curing unit, Apollo95E. The Optilux 501 was also evaluated for combinations of normal mode and boost mode and Standard tip and Turbo tip light guide. The spectral output of each unit was measured from 300 to 600 nm with a spectroradiometer. The light intensities at distances of zero, five, 10, 15, and 20 mm were determined with the radiometer. The peak value of Ortholux LED and The Cure surpassed that of Apollo95E. The light intensity significantly decreased with distance. Although The Cure showed a higher light intensity than the LEDemetron1 at zero-mm distance, the light intensity of the LEDemetron1 was higher than that of The Cure at five to 20 mm, resulting in no significant difference. The boost mode increased light intensity at any distance. Although the Turbo tip enhanced light intensity at zero-mm distance, reduction of light intensity by Turbo tip was demonstrated at five- to 20-mm distance.

  20. Light curing of resin-based composites in the LED era.

    PubMed

    Krämer, Norbert; Lohbauer, Ulrich; García-Godoy, Franklin; Frankenberger, Roland

    2008-06-01

    This review thoroughly accumulated information regarding new technologies for state-of-the-art light curing of resin composite materials. Visible light cured resin-based composites allow the dentist to navigate the initiation of the polymerization step for each layer being applied. Curing technology was regularly subjected to changes during the last decades, but meanwhile the LED era is fully established. Today, four main polymerization types are available, i.e. halogen bulbs, plasma are lamps, argon ion lasers, and light emitting diodes. Additionally, different curing protocols should help to improve photopolymerization in terms of less stress being generated. Conclusions were: (1) with high-power LED units of the latest generation, curing time of 2 mm thick increments of resin composite can be reduced to 20 seconds to obtain durable results; (2) curing depth is fundamentally dependent on the distance of the resin composite to the light source, but only decisive when exceeding 6 mm; (3) polymerization kinetics can be modified for better marginal adaptation by softstart polymerization; however, in the majority of cavities this may not be the case; (4) adhesives should be light-cured separately for at least 10 seconds when resin composite is applied directly; (5) photocuring through indirect restorations such as ceramics is still a problem, therefore, both dual-cured adhesives and dual-cured composites and resin coating in any way are recommended; and (6) heat generation with high-power photopolymerization units should not be underestimated as a biological problem for both gingival and pulpal tissues.

  1. Influence of sample composition and processing parameters on the UV cure of clear coatings

    NASA Astrophysics Data System (ADS)

    Ruiz, C. S. B.; Machado, L. D. B.; Volponi, J. E.; Pino, E. S.

    2003-08-01

    Photocurable systems consist of functional macromolecules, which undergo polymerization and a photoinduced crosslinking reaction under UV irradiation. Radiation-curable coatings have gained importance because they are environmentally friendly and save more energy than conventional heat-curable processes. The performance of UV-curable coatings depends on their formulation and cure quality. The quality of UV radiation cure depends on lamp characteristics, photoinitiator (PI) content, film thickness, curing environment, substrate and temperature. The aim of this study was to evaluate the influence of coating thickness and UV radiation dose, as well as coating characteristics such as PI content and stabilizer additive composition, on the curing process.

  2. The plants, rituals and spells that 'cured' helminthiasis in Sicily

    PubMed Central

    Napoli, Mariangela

    2008-01-01

    Background The author reports on the plants, rituals and spells used against worms and the so-called scantu (fright) in some areas of Sicily. The work is based on ethnobotanical research carried out, prevalently, between 2002-2006, in some areas of Eastern, South-Eastern, North-Central and South-Central Sicily. Methods This research is based on dialogue. Senior 'healers' were contacted; furthermore, doctors, teachers, farmers and in general 'experts' with herbs and 'magic' rituals. Information was collected about the way the plants of folk medicine are prepared. The interviewees were also invited to recite prayers and spells against helminthiasis. Results The author has highlighted the importance of how, in some parts of Sicily, some ailments like helminthiasis and other correlated pathologies like scantu are 'treated' and, especially within the rural social classes, by folk medicine remedies, herbal practises, particular prayers, rituals and spells. Conclusion As regards health/illness, it should be noted that in the last ten years conventional medicine has provided very satisfactory results even resolving potentially mortal pathologies. However, in certain social classes, there is no real collaboration between conventional and folk medicine; so for some senior citizens, the 'healer' with his rituals and empirical and magical herbs is still the person to turn to for the 'cure' of particular ailments. Interest in these practises from ancestral heritage in an advanced country like Italy, is only relevant if the aim is to recoup a cultural identity which is already in decline. It is significant to report a piece: on 14 October 2007 the news on a well-known national Italian TV channel reported an interview with a 94 year-old man from Arbatax (Sardinia) referred to as a 'healer' because both his townspeople and others from all over the world go to him for his cures. He is not paid except in kind and has been known to cure St. Anthony's fire, burns, scalding and marine

  3. Synthesis, characterization and cure kinetics of polyaniline modified MMT clay/epoxy nanocomposites

    NASA Astrophysics Data System (ADS)

    Aykanat, Aydin

    This research work focuses on the synthesis characterization and processing of conducting polymer coated both carbon fiber and montmorillonite clay based nanoparticles to improve the mechanical, thermal, and adhesive properties of epoxy based micro and nano composites. The entire research work mainly consists of two parts. In the first part, homogeneous and uniform coatings of polyaniline were successfully deposited onto carbon fibers by aqueous electrodeposition technique using p-toluene sulfonic acid as the electrolyte. Electrochemical deposition of aniline was carried out by cyclic voltammetry in the potential range of -0.2 V to 1.0 V vs. SCE. The electrochemical deposition parameters such as the number of cycles, scan rate (SR), initial monomer ([M]) and electrolyte concentration ([E]) were systematically varied. The amount of composite coatings on carbon fibers was dependant on the electrochemical deposition parameters. From the weight gain analysis, rate of the reactions (Rp) were calculated. As the aniline concentration was increased up to 0.35 M and electrolyte concentration up to 0.5 M, the deposition rate also increased, whereas an increase in scan rate decreased the deposition rate. The kinetic analysis showed that the rate equation for the p-toluene sulfonic acid system is R p ∝ SR-1.25 [M]0.73 [E]0.95 . IR spectra also show an increase in the deposition of polyaniline coatings on carbon fibers with a decrease in the scan rate and an increase in both monomer and electrolyte concentration. The ratio of two oxidation states of polyaniline namely emeraldine and pernigraniline obtained during electrodeposition can be varied by changing the electrochemical deposition parameters. SEM results show that carbon fiber surface was uniformly coated with polyaniline resulting a dense, rough and reactive surface that increases the compatibility and wettability of carbon fibers. The effect of PANi coated carbon fibers on the curing behavior of diglycidyl ether of

  4. HIV Therapeutic Vaccines: Moving towards a Functional Cure

    PubMed Central

    Mylvaganam, Geetha H.; Silvestri, Guido; Amara, Rama Rao

    2015-01-01

    Anti-viral T- and B- cell responses play a critical role in suppressing HIV and SIV replication during chronic infection. However, these infections are rarely controlled by the host immune response, and most infected individuals need lifelong antiretroviral therapy (ART). Recent advances in our understanding of how anti-HIV immune responses are elicited and regulated prompted a surge of interest in harnessing these responses to reduce the HIV "residual disease" that is present in ART-treated HIV-infected individuals. Novel approaches that are currently explored include both conventional therapeutic vaccines (i.e., active immunization strategies using HIV-derived immunogens) as well as the use of checkpoint blockers such as anti-PD-1 antibodies. These approaches appear promising as key components of complex therapeutic strategies aimed at curing HIV infection. PMID:25996629

  5. Optimization of instrumental colour analysis in dry-cured ham.

    PubMed

    García-Esteban, Marta; Ansorena, Diana; Gimeno, Olga; Astiasarán, Iciar

    2003-03-01

    Colour of dry cured ham was measured by instrumental techniques in order to determine the optimum measurement index. Five different colour systems were used: CIE L(∗)a(∗)b(∗), Hunter Lab, CIE L(∗)u(∗)v(∗), xyY and XYZ, each with illuminants D65, C and A, and with both 10 and 2° observer angles. Measurements were taken in both Semimembranosus (SM) and Biceps femoris (BF) muscles. Hunter Lab system with illuminant A gave the most reproducible results within muscles for the three colour parameters evaluated. A further comparison of results obtained with 10 and 2° observer angles of Hunter Lab with illuminant A showed there were no significant differences between the angles. Significant differences between results from SM and BF muscles were found in all the hams, the BF always showing higher values than SM for every colour parameter.

  6. HIV therapeutic vaccines: moving towards a functional cure.

    PubMed

    Mylvaganam, Geetha H; Silvestri, Guido; Amara, Rama Rao

    2015-08-01

    Anti-viral T-cell and B-cell responses play a crucial role in suppressing HIV and SIV replication during chronic infection. However, these infections are rarely controlled by the host immune response, and most infected individuals need lifelong antiretroviral therapy (ART). Recent advances in our understanding of how anti-HIV immune responses are elicited and regulated prompted a surge of interest in harnessing these responses to reduce the HIV 'residual disease' that is present in ART-treated HIV-infected individuals. Novel approaches that are currently explored include both conventional therapeutic vaccines (i.e., active immunization strategies using HIV-derived immunogens) as well as the use of checkpoint blockers such as anti-PD-1 antibodies. These approaches appear promising as key components of complex therapeutic strategies aimed at curing HIV infection.

  7. Cured-in-place pipe reconstruction of existing underground systems

    SciTech Connect

    Knasel, J.

    1995-09-01

    This paper describes InLiner USA{reg_sign} which is a cost effective process that allows pipes to be rebuilt without digging and avoids disturbing the area surrounding the pipe. This cured-in-place pipe (CIPP) technology is a unique process for reconstructing deteriorated pipe line systems in municipal and industry applications, which includes powerplants. The process uses a resin that coats and rebuilds th interior of the pipe to improve its structural integrity and corrosion resistance. CIPP creates continuous, seamless construction which increases flow capacities, stops infiltration, improves structural strength, resists long term corrosion and forms its own pipe within a pipe. It can be installed in a matter of hours or days and can be utilized in gravity and pressure pipes for storm sewers, sanitary sewers, combined sewers, water mains, gas mains and process piping.

  8. Targeting the latent reservoir to achieve functional HIV cure

    PubMed Central

    Cary, Daniele C.; Peterlin, B. Matija

    2016-01-01

    While highly active anti-retroviral therapy has greatly improved the lives of HIV-infected individuals, current treatments are unable to completely eradicate the virus. This is due to the presence of HIV latently infected cells which harbor transcriptionally silent HIV. Latent HIV does not replicate or produce viral proteins, thereby preventing efficient targeting by anti-retroviral drugs. Strategies to target the HIV latent reservoir include viral reactivation, enhancing host defense mechanisms, keeping latent HIV silent, and using gene therapy techniques to knock out or reactivate latent HIV. While research into each of these areas has yielded promising results, currently no one mechanism eradicates latent HIV. Instead, combinations of these approaches should be considered for a potential HIV functional cure. PMID:27303638

  9. Oh the irony: Iron as a cancer cause or cure?

    PubMed

    Foy, Susan P; Labhasetwar, Vinod

    2011-12-01

    Iron-oxide nanoparticles facilitate cancer diagnosis through enhanced contrast, selectively enhance tumor cell death with magnetic hyperthermia, and improve drug delivery with magnetic drug targeting. One application that remains largely unexplored is using the iron-oxide nanoparticles themselves to selectively inhibit tumor growth. In this leading opinion paper, we propose that high doses of iron-oxide nanoparticles can be used as a treatment for cancer by generating an oxidative assault against cancer. This proposal may be met with resistance considering the controversy surrounding iron in the field of cancer. Iron generates reactive oxygen species through the Fenton reaction, which may both cause - or cure cancer. Additionally, high demand for iron by cancer cells leads to contradictory therapeutic approaches: iron deprivation or overdose are both potential cancer therapies.

  10. HIV reservoirs as obstacles and opportunities for an HIV cure.

    PubMed

    Chun, Tae-Wook; Moir, Susan; Fauci, Anthony S

    2015-06-01

    The persistence of HIV reservoirs remains a formidable obstacle to achieving sustained virologic remission in HIV-infected individuals after antiretroviral therapy (ART) is discontinued, even if plasma viremia has been successfully suppressed for prolonged periods of time. Numerous approaches aimed at eradicating the virus, as well as maintaining its prolonged suppression in the absence of ART, have had little success. A better understanding of the pathophysiologic nature of HIV reservoirs and the impact of various interventions on their persistence is essential for the development of successful therapeutic strategies against HIV or the long-term control of infection. Here, we discuss the persistent HIV reservoir as a barrier to cure as well as the current therapeutic strategies aimed at eliminating or controlling the virus in the absence of ART.

  11. Ultrasonic transducers for cure monitoring: design, modelling and validation

    NASA Astrophysics Data System (ADS)

    Lionetto, Francesca; Montagna, Francesco; Maffezzoli, Alfonso

    2011-12-01

    The finite element method (FEM) has been applied to simulate the ultrasonic wave propagation in a multilayered transducer, expressly designed for high-frequency dynamic mechanical analysis of polymers. The FEM model includes an electro-acoustic (active element) and some acoustic (passive elements) transmission lines. The simulation of the acoustic propagation accounts for the interaction between the piezoceramic and the materials in the buffer rod and backing, and the coupling between the electric and mechanical properties of the piezoelectric material. As a result of the simulations, the geometry and size of the modelled ultrasonic transducer has been optimized and used for the realization of a prototype transducer for cure monitoring. The transducer performance has been validated by measuring the velocity changes during the polymerization of a thermosetting matrix of composite materials.

  12. Critique and cure: a dream of uniting psychoanalysis and philosophy.

    PubMed

    Webster, Jamieson

    2013-06-01

    Critical theory, whose aim was to historicize philosophy through integrating it with the social sciences, turned to psychoanalysis to find its way through an accounting of philosophy after the Second World War. Over 50 years after this initial project, the rift between philosophy and psychoanalysis has never been greater. If Jacques Lacan could be considered one of the few psychoanalysts to maintain and foster links to philosophical thought in the latter half of the 20th century, his work has sadly remained marginal in the clinical field throughout America and Europe. Both critical theory and Lacan remain skeptical of the direction taken by psychoanalysis after Freud. Reflecting on the history of these two disciplines, as well as through an examination of Theodor Adorno's posthumously published dream journal, critique and cure emerge as two dialectically intertwined themes that gain momentum in the dream of the unification of the philosophical and psychoanalytic projects.

  13. Characterization of heat emission of light-curing units

    PubMed Central

    Wahbi, Mohammed A.; Aalam, F.A.; Fatiny, F.I.; Radwan, S.A.; Eshan, I.Y.; Al-Samadani, K.H.

    2012-01-01

    Objectives This study was designed to analyze the heat emissions produced by light-curing units (LCUs) of different intensities during their operation. The null hypothesis was that the tested LCUs would show no differences in their temperature rises. Methods Five commercially available LCUs were tested: a “Flipo” plasma arc, “Cromalux 100” quartz–tungsten–halogen, “L.E. Demetron 1” second-generation light-emitting diode (LED), and “Blue Phase C5” and “UltraLume 5” third-generation LED LCUs. The intensity of each LCU was measured with two radiometers. The temperature rise due to illumination was registered with a type-K thermocouple, which was connected to a computer-based data acquisition system. Temperature changes were recorded in continues 10 and 20 s intervals up to 300 s. Results The Flipo (ARC) light source revealed the highest mean heat emission while the L.E. Demetron 1 LED showing the lowest mean value at 10 and 20 s exposure times. Moreover, Cromalux (QTH) recorded the second highest value for all intervals (12.71, 14.63, 14.60) of heat emission than Blue Phase C5 (LED) (12.25, 13.87, 13.69), interestingly at 20 s illumination for all intervals the highest results (18.15, 19.27, 20.31) were also recorded with Flipo (PAC) LCU, and the lowest (6.71, 5.97, 5.55) with L.E. Demetron 1 LED, while Blue Phase C5 (LED) recorded the second highest value at the 1st and 2nd 20 s intervals (14.12, 11.84, 10.18) of heat emission than Cromalux (QTH) (12.26, 11.43, 10.26). The speed of temperature or heat rise during the 10 and 20 s depends on light intensity of emitted light. However, the QTH LCU was investigated resulted in a higher temperature rise than LED curing units of the same power density. Conclusion The PAC curing unit induced a significantly higher heat emission and temperature increase in all periods, and data were statistically different than the other tested groups (p < .05). LED (Blue Phase C5) was not statistically

  14. Curing neurophobia in medical schools: evidence-based strategies

    PubMed Central

    Abushouk, Abdelrahman Ibrahim; Duc, Nguyen Minh

    2016-01-01

    Medical students often perceive neurology as the most difficult medical specialty. This perception is described as ‘neurophobia’ in the medical literature. Several studies have cited poor teaching, complex examination, and separation of basic and clinical sciences as major factors in the development of neurophobia. These negative perceptions can have serious implications, such as decreasing the students’ desire to consider neurology as a future career and increasing referrals from other specialists to avoid dealing with neurological conditions. Faced with increasing demands of healthcare systems and the global burden of neurological conditions, there is a rising need for further research and innovative strategies to improve students’ perceptions of clinical neurology. This review discusses evidence-based recommendations and educational interventions to cure neurophobia in medical education. PMID:27680578

  15. Health Problems of Epoxy Resins and Amine-curing Agents

    PubMed Central

    Bourne, L. B.; Milner, F. J. M.; Alberman, K. B.

    1959-01-01

    Epoxy resins were first introduced about 10 years ago. Toxic effects, particularly dermatitis, have been frequently described. An investigation into the possible causes of pathological sequelae following the use of epoxy resin/amine mixtures has been undertaken. The cause of most cases of dermatitis and sensitization appears to be uncombined amine which is present in recent mixtures and persists in hardened resin for long periods. The results of experiments with two of the most commonly used resin/amine mixtures confirm this. Cold-cured resins are more dangerous and remain so even when hardened. A simple theory is suggested for the mechanism of the reaction between epoxy resins, amines, and biological systems. This theory leads logically to the handling precautions outlined. Images PMID:13651551

  16. Looking back and to the future: Are we improving 'cure' in non-small cell lung cancer?

    PubMed

    Walder, David; O'Brien, Mary

    2017-02-22

    In surgical series, cancer-free survival at 5 years is often referred to as a cure. In recent years, attempts to improve cure rates in non-small cell lung cancer (NSCLC) have focussed on earlier diagnosis through cost-effective screening programs. Systemic therapies have historically added only a small benefit to overall survival in both the adjuvant and palliative setting. However, in the last two decades, the development of new treatment options has added incremental improvements in NSCLC survival rates. Patients with a targetable sensitising mutation including epidermal growth factor receptor gene mutations and anaplastic lymphoma kinase rearrangements have significantly better prognosis, and many will survive beyond 5 years. Immunotherapy is an effective treatment in selected patients with NSCLC and is set to cause another leap in 5 year survival rates. Although these patients are not free from disease, survival at 5 years may become the more important end-point as NSCLC becomes seen as a chronic oncological disease.

  17. An Evaluation of Fracture Toughness of Vinyl Ester Composites Cured under Microwave Conditions

    NASA Astrophysics Data System (ADS)

    Ku, H.; Chan, W. L.; Trada, M.; Baddeley, D.

    2007-12-01

    The shrinkage of vinyl ester particulate composites has been reduced by curing the resins under microwave conditions. The reduction in the shrinkage of the resins by microwaves will enable the manufacture of large vinyl ester composite items possible (H.S. Ku, G. Van Erp, J.A.R. Ball, and S. Ayers, Shrinkage Reduction of Thermoset Fibre Composites during Hardening using Microwaves Irradiation for Curing, Proceedings, Second World Engineering Congress, Kuching, Malaysia, 2002a, 22-25 July, p 177-182; H.S. Ku, Risks Involved in Curing Vinyl Ester Resins Using Microwaves Irradiation. J. Mater. Synth. Proces. 2002b, 10(2), p 97-106; S.H. Ku, Curing Vinyl Ester Particle Reinforced Composites Using Microwaves. J. Comp. Mater., (2003a), 37(22), p 2027-2042; S.H. Ku and E. Siores, Shrinkage Reduction of Thermoset Matrix Particle Reinforced Composites During Hardening Using Microwaves Irradiation, Trans. Hong Kong Inst. Eng., 2004, 11(3), p 29-34). In tensile tests, the yield strengths of samples cured under microwave conditions obtained are within 5% of those obtained by ambient curing; it is also found that with 180 W microwave power, the tensile strengths obtained for all duration of exposure to microwaves are also within the 5% of those obtained by ambient curing. While, with 360 W microwave power, the tensile strengths obtained for all duration of exposure to microwaves are 5% higher than those obtained by ambient curing. Whereas, with 540 W microwave power, the tensile strengths obtained for most samples are 5% below those obtained by ambient curing (H. Ku, V.C. Puttgunta, and M. Trada, Young’s Modulus of Vinyl Ester Composites Cured by Microwave Irradiation: Preliminary Results, J. Electromagnet. Waves Appl., 2007, 20(14), p. 1911-1924). This project, using 33% by weight fly ash reinforced vinyl ester composite [VE/FLYSH (33%)], is to further investigate the difference in fracture toughness between microwave cured vinyl ester particulate composites and those cured

  18. Curing kinetics and thermomechanical properties of latent epoxy/carbon fiber composites

    NASA Astrophysics Data System (ADS)

    Dalle Vacche, S.; Michaud, V.; Demierre, M.; Bourban, P.-E.; Månson, J.-A. E.

    2016-07-01

    In this work, resins based on diglycidyl ether of bisphenol A (DGEBA) epoxy and a latent hardener, dicyandiamide (DICY), as well as carbon fiber (CF) composites based on them, were prepared with three commercial accelerators: a methylene bis (phenyl dimethyl urea), a cycloaliphatic substituted urea, and a modified polyamine. The curing kinetics of the three DGEBA/DICY/accelerator systems were investigated by chemorheology and differential scanning calorimetry (DSC), in isothermal and over temperature change conditions. Differences in the reaction onset temperature, and in the glass transition temperature (Tg) were highlighted. For curing of thick resin samples, a slow curing cycle at the lowest possible temperature was used, followed by high temperature (160 - 180 °C) post-curing. Indeed, fast curing at higher temperatures caused the formation of hot spots and led to local burning of the samples. The obtained thermomechanical properties, assessed by ultimate tensile testing and dynamic mechanical analysis (DMA) in single cantilever configuration, were all in the expected range for epoxy resins, with tensile moduli close to 3 GPa and Tg > 140 °C. The longterm stability of these resins at room temperature was verified by DSC. Composite samples were prepared by hand lay-up by manually impregnating four layers of 5-harness satin CF textile, and curing in vacuum bag. Impregnation quality and void content were assessed by optical microscopy. The flexural properties of the post-cured composites were assessed by three-point bending test at room temperature and showed no relevant differences, all composites having bending moduli of 45 - 50 GPa. Finally, composites cured with a faster high temperature curing cycle (20 min at 140 °C) were prepared with the DGEBA/DICY/ methylene bis (phenyl dimethyl urea) system, obtaining similar properties as with the slower curing cycle, showing that the prepreg system allowed more flexibility in terms of curing cycle than the bulk resin

  19. Effect of Different Thicknesses of Pressable Ceramic Veneers on Polymerization of Light-cured and Dual-cured Resin Cements

    PubMed Central

    Cho, Seok-Hwan; Lopez, Arnaldo; Berzins, David W.; Prasad, Soni; Ahn, Kwang Woo

    2015-01-01

    Aim This study evaluated the effects of ceramic veneer thicknesses on the polymerization of two different resin cements. Materials and Methods A total of 80 ceramic veneer discs were fabricated by using a pressable ceramic material (e.max Press; Ivoclar Vivadent) from a Low Translucency (LT) ingot (A1 shade). These discs were divided into light-cured (LC; NX3 Nexus LC; Kerr) and dual-cured (DC; NX3 Nexus DC; Kerr) and each group was further divided into 4 subgroups, based on ceramic disc thickness (0.3 mm, 0.6 mm, 0.9 mm, and 1.2 mm). The values of Vickers microhardness (MH) and degree of conversion (DOC) were obtained for each specimen after a 24-hour storage period. Association between ceramic thickness, resin cement type, and light intensity readings (mW/cm2) with respect to microhardness and degree of conversion was statistically evaluated by using ANOVA. Results For the DOC values, there was no significant difference observed among the LC resin cement subgroups, except in the 1.2 mm subgroup; only the DOC value (14.0 ± 7.4%) of 1.2 mm DC resin cement had significantly difference from that value (28.9 ± 7.5%) of 1.2 mm LC resin cement (P<.05). For the MH values between LC and DC resin cement groups, there was statistically significant difference (P<.05); overall, the MH values of LC resin cement groups demonstrated higher values than DC resin cement groups. On the other hands, among the DC resin cement subgroups, the MH values of 1.2 mm DC subgroup was significantly lower than the 0.3 mm and 0.6 mm subgroups (P<.05). However, among the LC subgroups, there was no statistically significant difference among them (P >.05). Conclusion The degree of conversion and hardness of the resin cement was unaffected with veneering thicknesses between 0.3 and 0.9 mm. However, the DC resin cement group resulted in a significantly lower DOC and MH values for the 1.2 mm subgroup. Clinical Significance While clinically adequate polymerization of LC resin cement can be achieved

  20. Microhardness of resin composites polymerized by plasma arc or conventional visible light curing.

    PubMed

    Park, S Ho; Krejci, I; Lutz, F

    2002-01-01

    This study evaluated the effectiveness of the plasma arc curing (PAC) unit for composite curing. To compare its effectiveness with conventional quartz tungsten halogen (QTH) light curing units, the microhardness of two composites (Z100 and Tetric Ceram) that had been light cured by the PAC or QTH units, were compared according to the depth from the composite surface. In addition, linear polymerization shrinkage was compared using a custom-made linometer between composites which were light cured by PAC or QTH units. Measuring polymerization shrinkage for two resin composites (Z100 and Tetric Ceram) was performed after polymerization with either QTH or PAC units. In the case of curing with the PAC unit, the composite was light cured with Apollo 95E for two (Group 1), three (Group 2), six (Group 3) or 2 x 6 (Group 4) seconds. For light curing with the QTH unit, the composite was light cured for 60 seconds with Optilux 500 (Group 5). The linear polymerization shrinkage of composites was determined in the linometer. Two resin composites were used to measure microhardness. Two-mm thick samples were light cured for three seconds (Group 1), six seconds (Group 2) or 12 (2 x 6) seconds (Group 3) with Apollo 95E or they were conventionally light cured with Optilux 500 for 30 seconds (Group 4) or 60 seconds (Group 5). For 3 mm thick samples, the composites were light cured for six seconds (Group 1), 12 (2 x 6) seconds (Group 2) or 18 (3 x 6) seconds (Group 3) with Apollo 95E or they were conventionally light cured with Optilux 500 for 30 seconds (Group 4) or 60 seconds (Group 5). Twenty samples were assigned to each group. The microhardness of the upper and lower surfaces was measured with a Vickers hardness-measuring instrument under load. The difference in microhardness between the upper and lower surfaces in each group was analyzed by paired t-test. For the upper or lower surfaces, one-way ANOVA with Tukey was used. For Tetric Ceram, the amount of polymerization shrinkage