Anti-proliferative therapy for HIV cure: a compound interest approach.

PubMed

Reeves, Daniel B; Duke, Elizabeth R; Hughes, Sean M; Prlic, Martin; Hladik, Florian; Schiffer, Joshua T

2017-06-21

In the era of antiretroviral therapy (ART), HIV-1 infection is no longer tantamount to early death. Yet the benefits of treatment are available only to those who can access, afford, and tolerate taking daily pills. True cure is challenged by HIV latency, the ability of chromosomally integrated virus to persist within memory CD4 + T cells in a non-replicative state and activate when ART is discontinued. Using a mathematical model of HIV dynamics, we demonstrate that treatment strategies offering modest but continual enhancement of reservoir clearance rates result in faster cure than abrupt, one-time reductions in reservoir size. We frame this concept in terms of compounding interest: small changes in interest rate drastically improve returns over time. On ART, latent cell proliferation rates are orders of magnitude larger than activation and new infection rates. Contingent on subtypes of cells that may make up the reservoir and their respective proliferation rates, our model predicts that coupling clinically available, anti-proliferative therapies with ART could result in functional cure within 2-10 years rather than several decades on ART alone.

Current estimates of the cure fraction: a feasibility study of statistical cure for breast and colorectal cancer.

PubMed

Stedman, Margaret R; Feuer, Eric J; Mariotto, Angela B

2014-11-01

The probability of cure is a long-term prognostic measure of cancer survival. Estimates of the cure fraction, the proportion of patients "cured" of the disease, are based on extrapolating survival models beyond the range of data. The objective of this work is to evaluate the sensitivity of cure fraction estimates to model choice and study design. Data were obtained from the Surveillance, Epidemiology, and End Results (SEER)-9 registries to construct a cohort of breast and colorectal cancer patients diagnosed from 1975 to 1985. In a sensitivity analysis, cure fraction estimates are compared from different study designs with short- and long-term follow-up. Methods tested include: cause-specific and relative survival, parametric mixture, and flexible models. In a separate analysis, estimates are projected for 2008 diagnoses using study designs including the full cohort (1975-2008 diagnoses) and restricted to recent diagnoses (1998-2008) with follow-up to 2009. We show that flexible models often provide higher estimates of the cure fraction compared to parametric mixture models. Log normal models generate lower estimates than Weibull parametric models. In general, 12 years is enough follow-up time to estimate the cure fraction for regional and distant stage colorectal cancer but not for breast cancer. 2008 colorectal cure projections show a 15% increase in the cure fraction since 1985. Estimates of the cure fraction are model and study design dependent. It is best to compare results from multiple models and examine model fit to determine the reliability of the estimate. Early-stage cancers are sensitive to survival type and follow-up time because of their longer survival. More flexible models are susceptible to slight fluctuations in the shape of the survival curve which can influence the stability of the estimate; however, stability may be improved by lengthening follow-up and restricting the cohort to reduce heterogeneity in the data. Published by Oxford University Press 2014.

Advanced Powder Coating Systems for Military Applications

DTIC Science & Technology

2011-05-01

UVCPC • Conclusions • DoD spends billions of dollars annually on protective organic coatings – Hexavalent chrome primer use still widespread – Contains...Elimination of Hazardous Air Pollutants (HAP) • Reduction/Elimination of ESOH Concerns – Elimination of hexavalent chromium – Elimination of free...production and release; hexavalent chromium; free isocyanates; up to 72 hrs “dry to fly” time Longer cure times than traditional primers and

Micro-resonator-based electric field sensors with long durations of sensitivity

NASA Astrophysics Data System (ADS)

Ali, Amir R.

2017-05-01

In this paper, we present a new fabrication method for the whispering gallery mode (WGM) micro-sphere based electric field sensor that which allows for longer time periods of sensitivity. Recently, a WGM-based photonic electric field sensor was proposed using a coupled dielectric microsphere-beam. The external electric field imposes an electrtrostriction force on the dielectric beam, deflecting it. The beam, in turn compresses the sphere causing a shift in its WGM. As part of the fabrication process, the PDMS micro-beams and the spheres are curied at high-temperature (100oC) and subsequently poled by exposing to strong external electric field ( 8 MV/m) for two hours. The poling process allows for the deposition of surface charges thereby increasing the electrostriction effect. This methodology is called curing-then-poling (CTP). Although the sensors do become sufficiently sensitive to electric field, they start de-poling after a short period (within 10 minutes) after poling, hence losing sensitivity. In an attempt to mitigate this problem and to lock the polarization for a longer period, we use an alternate methodology whereby the beam is poled and cured simultaneously (curing-while-poling or CWP). The new fabrication method allows for the retention of polarization (and hence, sensitivity to electric field) longer ( 1500 minutes). An analysis is carried out along with preliminary experiments. Results show that electric fields as small as 100 V/m can be detected with a 300 μm diameter sphere sensor a day after poling.

Experimental and Numerical Analysis of the Effects of Curing Time on Tensile Mechanical Properties of Thin Spray-on Liners

NASA Astrophysics Data System (ADS)

Guner, D.; Ozturk, H.

2016-08-01

The effects of curing time on tensile elastic material properties of thin spray-on liners (TSLs) were investigated in this study. Two different TSL products supplied by two manufacturers were tested comparatively. The "dogbone" tensile test samples that were prepared in laboratory conditions with different curing times (1, 7, 14, 21, and 28 days) were tested based on ASTM standards. It was concluded that longer curing times improves the tensile strength and the Young's Modulus of the TSLs but decreases their elongation at break. Moreover, as an additional conclusion of the testing procedure, it was observed that during the tensile tests, the common malpractice of measuring sample displacement from the grips of the loading machine with a linear variable displacement transducer versus the sample's gauge length had a major impact on modulus and deformation determination of TSLs. To our knowledge, true stress-strain curves were generated for the first time in TSL literature within this study. Numerical analyses of the laboratory tests were also conducted using Particle Flow Code in 2 Dimensions (PFC2D) in an attempt to guide TSL researchers throughout the rigorous PFC simulation process to model support behaviour of TSLs. A scaling coefficient between macro- and micro-properties of PFC was calculated which will help future TSL PFC modellers mimic their TSL behaviours for various tensile loading support scenarios.

Development and evaluation of epoxidized soybean oil-based polymers

NASA Astrophysics Data System (ADS)

Juangvanich, Nuanpen

Epoxidized Soybean Oil (ESO) based polymers were developed using diamine curing agents and BF3:NH2C2H5 as catalyst. Reactions involved the curing process were explored and monitored by DSC and IR analysis. Amine-epoxy addition reactions governed the main curing reaction at the temperature range of 60--235°C, and the supplementary reactions at higher temperatures were either homopolymerization or etherification reaction. In the aliphatic curing reactions, the epoxy-rich system favored the supplementary reactions at high temperature, however, ESO cured with 1,6 hexanediamine (HDA) always produced the high temperature reaction products, due to some side reactions and the high volatile nature. The curing reaction with aromatic diamines produced inherent rigidity to the cured ESO network, which decreased the high temperature reactions. The system cured with a short aromatic diamine, 1,4-phenyldiamine (PDA), produced a small extent of high temperature reaction, as well. It was believed that the long length diamine with wide separation of the two amines underwent an intermolecular cross-linking reaction, and derived better properties than the shorter diamine. A post-cure process was used to improve the final polymer properties by increasing the temperature after the initial curing reaction was quenched due to gelation. Extending the time of post-curing did not significantly improve properties of the final ESO polymers. Exposing the cured samples at 180°C for longer than 12 hours decreased the properties of the cured material, due to thermal strain generating in the network structure. To increase time efficiency, short heat cycles were performed by post-curing right after gelation, and the cured ESO polymer had tensile strength of 32 MPa, modulus 750 MPa and toughness 1.3 MPa. With the introduction of EPON 828, the mechanical properties of a new ESO polymer improved; having strength above 40 MPa, modulus great than 1,000 MPa, and Tg higher than 40°C. Finally, a rice hull particleboard was developed using the cured ESO resin as adhesive, and the board had strength comparable to the National Bureau of Standards minimum requirement for particleboard. A 35 wt % of ESO resin imparted the highest strength for the rice hull board, with a value of 15.5 MPa.

Chromium liquid waste inertization in an inorganic alkali activated matrix: leaching and NMR multinuclear approach.

PubMed

Ponzoni, Chiara; Lancellotti, Isabella; Barbieri, Luisa; Spinella, Alberto; Saladino, Maria Luisa; Martino, Delia Chillura; Caponetti, Eugenio; Armetta, Francesco; Leonelli, Cristina

2015-04-09

A class of inorganic binders, also known as geopolymers, can be obtained by alkali activation of aluminosilicate powders at room temperature. The process is affected by many parameters (curing time, curing temperature, relative humidity etc.) and leads to a resistant matrix usable for inertization of hazardous waste. In this study an industrial liquid waste containing a high amount of chromium (≈ 2.3 wt%) in the form of metalorganic salts is inertized into a metakaolin based geopolymer matrix. One of the innovative aspects is the exploitation of the water contained in the waste for the geopolymerization process. This avoided any drying treatment, a common step in the management of liquid hazardous waste. The evolution of the process--from the precursor dissolution to the final geopolymer matrix hardening--of different geopolymers containing a waste amount ranging from 3 to 20%wt and their capability to inertize chromium cations were studied by: i) the leaching tests, according to the EN 12,457 regulation, at different curing times (15, 28, 90 and 540 days) monitoring releases of chromium ions (Cr(III) and Cr(VI)) and the cations constituting the aluminosilicate matrix (Na, Si, Al); ii) the humidity variation for different curing times (15 and 540 days); iii) SEM characterization at different curing times (28 and 540 days); iv) the trend of the solution conductivity and pH during the leaching test; v) the characterization of the short-range ordering in terms of TOT bonds (where T is Al or Si) by (29)Si and (27)Al solid state magic-angle spinning nuclear magnetic resonance (ss MAS NMR) for geopolymers containing high amounts of waste (10-20%wt). The results show the formation of a stable matrix after only 15 days independently on the waste amount introduced; the longer curing times increase the matrices stabilities and their ability to immobilize chromium cations. The maximum amount of waste that can be inertized is around 10 wt% after a curing time of 28 days. Copyright © 2014 Elsevier B.V. All rights reserved.

Effect of mixing geopolymer and peat on bearing capacity in Ogan Komering Ilir (OKI) by California bearing ratio (CBR) test

NASA Astrophysics Data System (ADS)

Raharja, Danang S.; Hadiwardoyo, Sigit P.; Rahayu, Wiwik; Zain, Nasuhi

2017-06-01

Geopolymer is binder material that consists of solid material and the activator solution. Geopolymer material has successfully replaced cement in the manufacture of concrete with aluminosilicate bonding system. Geopolymer concrete has properties similar to cement concrete with high compressive strength, low shrinkage value, relatively low creep value, as well as acid-resistant. Based on these, the addition of polymers in peat soils is expected to improve the bearing capacity of peat soils. A study on the influence of geopolymer addition in peat soils was done by comparing before and after the peat soil was mixed with geopolymer using CBR (California Bearing Ratio) test in unsoaked and soaked conditions. 10% mixture content of the peat dry was used, weighted with a variety of curing time 4 hours, 5 days, and 10 days. There were two methods of mixing: first, peat was mixed with fly ash geopolymer activators and mixed solution (waterglass, NaOH, water), and second, peat was mixed with fly ash and mixed geopolymer (waterglass, NaOH, water, fly ash). Changes were observed in specific gravity, dry density, acidity (pH), and the microscopic structure with Scanning Electron Microscope (SEM). Curing time did not significantly affect the CBR value. It even shows a tendency to decline with longer curing time. The first type mixture obtained CBR value of: 5.4% for 4 hours curing, 4.6% for 5 days curing and 3.6% for 10 days curing. The second type mixture obtained CBR value of: 6.1% for 4 hours curing, 5.2% for 5 days curing and 5.2% for 10 days curing. Furthermore, the specific gravity value, dry density, pH near neutral and swelling percentage increased. From both variants, the second type mixture shows better results than the first type mixture. The results of SEM (Scanning Electron Microscopy) show the structure of the peat which became denser with the fly ash particles filling the peat microporous. Also, the reaction of fly ash with geopolymer is indicated by the solid agglomerates that are larger than normal fly ash particle size.

Effects of vegetable juice powder concentration and storage time on some chemical and sensory quality attributes of uncured, emulsified cooked sausages.

PubMed

Sindelar, J J; Cordray, J C; Sebranek, J G; Love, J A; Ahn, D U

2007-06-01

Uncured, no-nitrate/nitrite-added meat products can be manufactured with vegetable juice powder (VJP) and a starter culture containing Staphylococcus carnosus, resulting in quality and sensory attributes similar to traditional cured products. The 1st objective of this study was to determine the effects of varying concentrations of VJP and incubation times (MIN-HOLD) on quality characteristics, including lipid oxidation, color, and cured meat pigment concentrations, of emulsified-frankfurter-style-cooked (EFSC) sausages over a 90-d storage period. The 2nd objective was to compare residual nitrate and nitrite content resulting from different processing treatments and the 3rd objective was to assess sensory properties of finished products. Four EFSC sausage treatments (TRT) (TRT 1: 0.20% VJP, 30 MIN-HOLD; TRT 2: 0.20% VJP, 120 MIN-HOLD; TRT 3: 0.40% VJP, 30 MIN-HOLD; TRT 4: 0.40% VJP, 120 MIN-HOLD) and a sodium nitrite-added control (C) were used for this study. No differences for lipid oxidation (TBARS) between any TRTs and C or over time were observed. No differences (P > 0.05) for CIE L* values were found between TRTs. CIE a* and reflectance ratio values revealed that TRTs 2, 4, and C were redder than TRTs 1 and 3 at day 0. Trained sensory intensity ratings for cured aroma, cured color, cured flavor, uniform color, and firmness determined that all but TRT 1 were similar to C. These results indicate a longer incubation time (120 compared with 30 min) was found more critical than VJP level (0.20% or 0.40%) to result in products comparable to a sodium nitrite-added control.

Light-attenuating effect of dentin on the polymerization of light-activated restorative resins.

PubMed

Arikawa, Hiroyuki; Kanie, Takahito; Fujii, Koichi; Ban, Seiji; Takahashi, Hideo

2004-12-01

The light-attenuating effect of dentin on the mechanical properties of light-activated composite resins was evaluated using a simple experimental filter. The filter was designed to simulate the light transmittance and light diffusion characteristics of 1.0-mm thick dentin. The depth of cure, surface hardness, and flexural strength for 13 shades of three light-activated restorative resins were examined. These resins were cured either using direct irradiation with a light source, or indirect irradiation through the filter. The attenuation of light intensity by 1.0-mm thick dentin reached 85-90% in the 400-550 nm wavelength region. For all materials, the values of depth of cure, surface hardness on the top and bottom surfaces, and flexural strength of specimens irradiated indirectly through the simulated 1.0-mm thick dentin filter decreased by 37-60%, 16-55%, 50-83%, and 44-82% in comparison with those by direct irradiation, respectively. Recovery from mechanical properties' reduction was achieved when materials were irradiated 1.5-4 times longer than the standard irradiation time.

A novel sample size formula for the weighted log-rank test under the proportional hazards cure model.

PubMed

Xiong, Xiaoping; Wu, Jianrong

2017-01-01

The treatment of cancer has progressed dramatically in recent decades, such that it is no longer uncommon to see a cure or log-term survival in a significant proportion of patients with various types of cancer. To adequately account for the cure fraction when designing clinical trials, the cure models should be used. In this article, a sample size formula for the weighted log-rank test is derived under the fixed alternative hypothesis for the proportional hazards cure models. Simulation showed that the proposed sample size formula provides an accurate estimation of sample size for designing clinical trials under the proportional hazards cure models. Copyright © 2016 John Wiley & Sons, Ltd.

Effect of lactic acid-lactobacillus preservative and moisture concentration at baling on intake and digestibility of crabgrass hay by lambs and in-situ digestibility by heifers

USDA-ARS?s Scientific Manuscript database

Crabgrass is a warm-season annual forage that has greater nutritive value than most other warm-season grasses and is highly palatable, but curing time for crabgrass hay is typically longer than for bermudagrass. Crabgrass hay was either not treated or treated with a lactic acid-lactobacillus preserv...

Epoxy adhesive formulations for engineered wood manufacturing: Design of Experiment (DOE) and hardener modification

NASA Astrophysics Data System (ADS)

Wangkheeree, W.; Meekum, U.

2016-03-01

The effect of IPDA, DDS, BPA and DICY, as main ingredient of TETA based hardener were examined. The 2k design of experiment(DOE) with k=3 were preliminary explored. The designed parameters A(IPDA), B(DDS) and C(BPA) were assigned as low(-) and high(+) levels, respectively. The Design Expert™ was hired as the analyzing tool at α=0.05. The mixed epoxy resin was based on the commercial one. The designed responds including tcure, t50, impact strengths, flexural properties and HDT were measured, respectively. Regarding to ANOVA conclusion, it was found that, there were no significant effects on the assigned parameters on the interested responds, except for the HDT where BPA(C) was negative effect was found. The lower in the crosslink density of cured epoxy, inferior in HDT, the higher in BPA addition was hypothesized. It was found that impact strength of cured epoxy derived from all formula were unacceptable low and tcure and t50, were too short. Thus, the further investigation by adding DICY into hardener was explored. The results showed that no significant change by mechanical means of cured epoxy by resolving 5-30 phr of DICY into the hardener. However, it was observed that the DICY added formula showed the obvious long cure times and behave as prepreg formula. The room temperature cured epoxy was incompletely crosslinked. The degrees of linear chain fragment were evidence, by weight, when higher DICY loading was engaged. Complete crosslink was achieved at 150°C post curing. The hardener comprised of TETA/aliphatic Epoxy(RD108) adduct was studied for enhancing the toughness of epoxy resin. It was observed that longer cure time at 150°C but lower toughness was experienced, on both prepreg and engineered wood made from the resins, at high TETA/RD108 ratio. Incomplete cure was explained for the mechanical inferior at high RD108 loading.

Intelligent processing for thick composites

NASA Astrophysics Data System (ADS)

Shin, Daniel Dong-Ok

2000-10-01

Manufacturing thick composite parts are associated with adverse curing conditions such as large in-plane temperature gradient and exotherms. The condition is further aggravated because the manufacturer's cycle and the existing cure control systems do not adequately counter such affects. In response, the forecast-based thermal control system is developed to have better cure control for thick composites. Accurate cure kinetic model is crucial for correctly identifying the amount of heat generated for composite process simulation. A new technique for identifying cure parameters for Hercules AS4/3502 prepreg is presented by normalizing the DSC data. The cure kinetics is based on an autocatalytic model for the proposed method, which uses dynamic and isothermal DSC data to determine its parameters. Existing models are also used to determine kinetic parameters but rendered inadequate because of the material's temperature dependent final degree of cure. The model predictions determined from the new technique showed good agreement to both isothermal and dynamic DSC data. The final degree of cure was also in good agreement with experimental data. A realistic cure simulation model including bleeder ply analysis and compaction is validated with Hercules AS4/3501-6 based laminates. The nonsymmetrical temperature distribution resulting from the presence of bleeder plies agreed well to the model prediction. Some of the discrepancies in the predicted compaction behavior were attributed to inaccurate viscosity and permeability models. The temperature prediction was quite good for the 3cm laminate. The validated process simulation model along with cure kinetics model for AS4/3502 prepreg were integrated into the thermal control system. The 3cm Hercules AS4/3501-6 and AS4/3502 laminate were fabricated. The resulting cure cycles satisfied all imposed requirements by minimizing exotherms and temperature gradient. Although the duration of the cure cycles increased, such phenomena was inevitable since longer time was required to maintain acceptable temperature gradient. The derived cure cycles were slightly different than what was anticipated by the offline simulation. Nevertheless, the system adapted to unanticipated events to satisfy the cure requirements.

Purulent vaginal discharge in grazing dairy cows: Risk factors, reproductive performance, and prostaglandin F2α treatment.

PubMed

Giuliodori, M J; Magnasco, M; Magnasco, R P; Lacau-Mengido, I M; de la Sota, R L

2017-05-01

The objectives of this study were to assess the association of a 4-point scale of vaginal discharge score (VDS) with time to pregnancy to define criteria for a practical case of purulent vaginal discharge (PVD) in dairy cows, to test the risk factors for PVD, and, finally, the effect of a dose of PGF 2α on cure and reproductive performance. In experiment 1, grazing Holstein cows (n = 2,414) had their vaginal discharge scored at ∼32 d in milk (DIM) on a 4-point scale, the effect of VDS on the hazard of pregnancy by 300 DIM was then assessed to derive a case definition of PVD. Risk factors for PVD and self-cure were also assessed. In experiment 2, grazing Holstein cows (n = 6,326) from 5 herds were checked for PVD at ∼30 DIM. Cows with PVD were assigned to receive one dose of 500 μg of PGF 2α analog (Cloprostenol; Ciclase, Syntex SA, Buenos Aires, Argentina) per cow (odd ear tag number) or to remain untreated (even tag number). Cure was declared if cows presented clear normal vaginal discharge (VDS-0) at visit 2 (∼62 DIM). Data were analyzed with Cox's regression and mixed logistic models. In experiment 1, cows with VDS ≥1 had lower hazard of pregnancy and longer calving to pregnancy interval than cows with VDS-0. This finding was not affected by the time at which the diagnosis was performed. Therefore, a cow ≥21 DIM and having VDS ≥1 was used to define a case of PVD. The odds of PVD were greater in primiparous cows compared with multiparous, in cows with abnormal calving compared with those with normal calving, and in those losing BCS peripartum. In experiment 2, PGF 2α treatment tended to slightly increase the hazard of pregnancy (adjusted hazard ratio = 1.13). Conversely, PGF 2α had no effect on the odds of cure of PVD [adjusted odds ratio (AOR) = 1.19], pregnancy at first service (AOR = 1.03), or pregnancy by 100 DIM (AOR = 0.89) or 200 DIM (AOR = 1.27). In conclusion, cows with VDS ≥1 can be considered to have PVD because of their lower hazard of pregnancy and longer calving to pregnancy interval (up to 48 d). Important risk factors are parity, calving, and body condition score loss peripartum. Optimal time of diagnosis is ≥28 to 35 DIM because cows experience a high self-cure rate. Self-cure is also affected by parity, prepartum BCS, and VDS. Finally, as treatment with one dose of PGF 2α had a small effect on the hazard of pregnancy and no effect on clinical cure, its therapeutic use in grazing dairy cows with PVD is not recommended. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Collective antibiotic treatment of trachoma

PubMed Central

Reinhards, J.; Weber, A.; Maxwell-Lyons, F.

1959-01-01

By the early 1950's, it was clear from numerous independent reports that certain of the broad-spectrum antibiotics were effective against the agent of trachoma. It seemed, however, that treatment had to be continued over long periods to effect a cure of the average case. With the assistance of WHO, comparative trials on a scale hitherto unprecedented in the disease—involving more than 9000 schoolchildren with active trachoma—have been conducted in Morocco since 1953 in order to assess the value of local treatment of trachoma with chlortetracycline and to develop simple and economic methods of treatment, for which there was a pressing need. Local application of 1% chlortetracycline ointment two or three times daily for 60 days gave almost 80% cures under reasonably favourable conditions and nearly 100% cures after re-treatment of cases not cured by the first course. Equally good results followed intermittent short-term treatment over longer periods. Relapse and reinfection rates were low. Collective mass treatment with antibiotics is clearly a valuable method of trachoma control. The use of intermittent treatment allows for a great economy both in antibiotics and in staff and other campaign expenses and makes possible the wide expansion of mass treatment programmes. PMID:14437176

Microbiological and physicochemical characterization of dry-cured Halal goat meat. Effect of salting time and addition of olive oil and paprika covering.

PubMed

Cherroud, Sanâa; Cachaldora, Aida; Fonseca, Sonia; Laglaoui, Amin; Carballo, Javier; Franco, Inmaculada

2014-10-01

The objective of this work was to define a simple technological process for dry-cured Halal goat meat elaboration. The aims of this study were to analyze physicochemical parameters and to enumerate the microbial population at the end of the different manufacturing processes (two salting times and the addition of olive oil and paprika covering) on 36 units of meat product. A total of 532 strains were isolated from several selective culture media and then identified using classical and molecular methods. In general, salt effect and the addition of olive oil and paprika were significant for all the studied microbial groups as well as on NaCl content and water activity. Molecular analysis proves that staphylococci, especially Staphylococcus xylosus and Staphylococcus equorum, were the most common naturally occurring microbiota. The best manufacturing process would be obtained with a longer salting time and the addition of the olive oil and paprika covering. Copyright © 2014 Elsevier Ltd. All rights reserved.

Miracles Take a Little Longer: Science, Commercialisation, Cures and the Dore Program

ERIC Educational Resources Information Center

Stephenson, Jennifer; Wheldall, Kevin

2008-01-01

In this article, the evidence regarding a proposed "cure" for dyslexia and other, arguably related, conditions is examined critically. The origins and history of the Dore program and its progenitors, its introduction to Australia and its advertising claims are reviewed, with a focus on the claims made with regard to dyslexia, and…

Assessment of Salmonella survival in dry-cured Italian salami.

PubMed

Bonardi, S; Bruini, I; Bolzoni, L; Cozzolino, P; Pierantoni, M; Brindani, F; Bellotti, P; Renzi, M; Pongolini, S

2017-12-04

The inactivation of Salmonella during curing of Italian traditional pork salami was investigated. A total of 150 batches of ground raw meat (GRM) used for salami manufacturing by four producers were tested for Salmonella by real-time PCR followed by ISO 6579 cultural confirmation and MPN enumeration. Salami produced with Salmonella positive GRMs were re-tested at the end of their curing period. Aw, pH and NaCl content were also measured. Detection of Salmonella was performed testing both 25 and 50g of the samples. By Real-Time PCR 37% of the GRMs resulted positive, but cultural detection of Salmonella was obtained in 14% of the samples only. Salmonella enumeration ranged from 31 MPN/g to <1.3 MPN/g. The difference between testing 50g and 25g of the samples was statistically significant (p value≤0.01). In particular, ISO-50g detected Salmonella in 100% of all positive samples, vs. 62% of ISO-25g. Salami made of the contaminated GRMs were 29% Salmonella-positive, as most batches of salami produced with Salmonella-positive GRMs resulted negative after regular curing (20-48days). Overall, 13% of salami produced with Salmonella-contaminated GRMs were positive. They belonged to six batches, which turned out negative after prolonged curing ranging between 49 and 86days. Salmonella enumeration in salami ranged from 8.7 MPN/g to <1.3 MPN/g. Unlike GRMs, no significant difference was observed between the ISO-50g and the ISO-25g in detecting Salmonella in cured salami (p value: >0.05). The most common Salmonella serovars in GRMs were Derby (52%), Typhimurium monophasic variant 4, (Barbuti et al., 1993), 12:i:- (19%) and Stanley (10%). Salmonella Derby (56%), London, Branderup, Panama (13%, respectively) and Goldcoast (6%) were most frequent in cured salami. The study showed negative correlation between real-time CT values and cultural confirmation of Salmonella, as well as the importance of sample size for Salmonella detection. Among considered factors with possible effect on the occurrence of Salmonella in salami, statistical analysis revealed a role for aw in salami and for Salmonella load in GRMs, while pH and NaCl content did not significantly affect the probability of finding Salmonella in dry-cured salami in the context of this study. In particular the lower aw values due to longer curing were associated with lower Salmonella presence in traditional dry-cured salami. Copyright © 2017 Elsevier B.V. All rights reserved.

The Manned Penetrating Bomber: Time to Reconsider

DTIC Science & Technology

2016-06-01

choice: spend billions on nuclear weapons we no longer need or fund programs that educate our children and help find cures to deadly diseases. The...security of our nation’s future will be ensured by investing in education not nuclear annihilation…We need to stop pouring billions into the nuclear...event.61 Unfortunately, the president’s reaction to the launch received negative reviews from the general public. On a comical side note, the whole

Nonremission and time to remission among remitters in major depressive disorder: Revisiting STAR*D.

PubMed

Mojtabai, Ramin

2017-12-01

Some individuals with major depressive disorder do not experience a remission even after one or more adequate treatment trials. In some others who experience remission, it happens at variable times. This study sought to estimate the prevalence of nonremission in a large sample of patient participating in the Sequenced Treatment Alternatives to Relieve Depression (STAR*D) trial and to identify correlates of nonremission and time to remission among remitters. Using data from 3,606 participants of STAR*D, the study used cure regression modeling to estimate nonremission and jointly model correlates of nonremission and time to remission among the remitters. Overall, 14.7% of the STAR*D participants were estimated to be nonremitters. Among remitters, the rate of remission declined over time. Greater severity, poorer physical health, and poor adherence with treatments were associated with both nonremission and a longer time to remission among the remitters in multivariable analyses, whereas unemployment, not having higher education, and longer duration of current episode were uniquely associated with nonremission; whereas, treatment in specialty mental health settings, poorer mental health functioning, and greater impairment in role functioning with a longer time to remission among remitters. Poor treatment adherence and poor physical health appear to be common risk factors for both nonremission and longer time to remission, highlighting the importance of integrated care models that address both medical and mental healthcare needs and interventions aimed at improving treatment adherence. © 2017 Wiley Periodicals, Inc.

The proportion cured of patients diagnosed with Stage III-IV cutaneous malignant melanoma in Sweden 1990-2007: A population-based study.

PubMed

Eriksson, Hanna; Lyth, Johan; Andersson, Therese M-L

2016-06-15

The survival in cutaneous malignant melanoma (CMM) is highly dependent on the stage of the disease. Stage III-IV CMM patients are at high risk of relapse with a heterogeneous outcome, but not all experience excess mortality due to their disease. This group is referred to as the cure proportion representing the proportion of patients who experience the same mortality rate as the general population. The aim of this study was to estimate the cure proportion of patients diagnosed with Stage III-IV CMM in Sweden. From the population-based Swedish Melanoma Register, we included 856 patients diagnosed with primary Stage III-IV CMM, 1990-2007, followed-up through 2013. We used flexible parametric cure models to estimate cure proportions and median survival times (MSTs) of uncured by sex, age, tumor site, ulceration status (in Stage III patients) and disease stage. The standardized (over sex, age and site) cure proportion was lower in Stage IV CMMs (0.15, 95% CI 0.09-0.22) than non-ulcerated Stage III CMMs (0.48, 95% CI 0.41-0.55) with a statistically significant difference of 0.33 (95% CI = 0.24-0.41). Ulcerated Stage III CMMs had a cure proportion of 0.27 (95% CI 0.21-0.32) with a statistically significant difference compared to non-ulcerated Stage III CMMs (difference 0.21; 95% CI = 0.13-0.30). The standardized MST of uncured was approximately 9-10 months longer for non-ulcerated versus ulcerated Stage III CMMs. We could demonstrate a significantly better outcome in patients diagnosed with non-ulcerated Stage III CMMs compared to ulcerated Stage III CMMs and Stage IV disease after adjusting for age, sex and tumor site. © 2016 UICC.

Neurocognitive Function in Acromegaly after Surgical Resection of GH-Secreting Adenoma versus Naïve Acromegaly

PubMed Central

Martín-Rodríguez, Juan Francisco; Madrazo-Atutxa, Ainara; Venegas-Moreno, Eva; Benito-López, Pedro; Gálvez, María Ángeles; Cano, David A.; Tinahones, Francisco J.; Torres-Vela, Elena; Soto-Moreno, Alfonso; Leal-Cerro, Alfonso

2013-01-01

Patients with active untreated acromegaly show mild to moderate neurocognitive disorders that are associated to chronic exposure to growth hormone (GH) and insulin-like growth factor (IGF-I) hypersecretion. However, it is unknown whether these disorders improve after controlling GH/IGF-I hypersecretion. The aim of this study was to compare neurocognitive functions of patients who successfully underwent GH-secreting adenoma transsphenoidal surgery (cured patients) with patients with naive acromegaly. In addition, we wanted to determine the impact of different clinical and biochemical variables on neurocognitive status in patients with active disease and after long-term cure. A battery of six standardized neuropsychological tests assessed attention, memory and executive functioning. In addition, a quantitative electroencephalography with Low-Resolution Electromagnetic Tomography (LORETA) solution was performed to obtain information about the neurophysiological state of the patients. Neurocognitive data was compared to that of a healthy control group. Multiple linear regression analysis was also conducted using clinical and hormonal parameters to obtain a set of independent predictors of neurocognitive state before and after cure. Both groups of patients scored significantly poorer than the healthy controls on memory tests, especially those assessing visual and verbal recall. Patients with cured acromegaly did not obtain better cognitive measures than naïve patients. Furthermore memory deficits were associated with decreased beta activity in left medial temporal cortex in both groups of patients. Regression analysis showed longer duration of untreated acromegaly was associated with more severe neurocognitive complications, regardless of the diagnostic group, whereas GH levels at the time of assessment was related to neurocognitive outcome only in naïve patients. Longer duration of post-operative biochemical remission of acromegaly was associated with better neurocognitive state. Overall, this data suggests that the effects of chronic exposure to GH/IGF-I hypersecretion could have long-term effects on brain functions. PMID:23593161

Long-term survival, prevalence, and cure of cancer: a population-based estimation for 818 902 Italian patients and 26 cancer types.

PubMed

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

2014-11-01

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. 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. 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%. 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. © The Author 2014. Published by Oxford University Press on behalf of the European Society for Medical Oncology.

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

Herbal cancer cures on the Web: noncompliance with The Dietary Supplement Health and Education Act.

PubMed

Bonakdar, Robert Alan

2002-01-01

A significant portion of the US population uses the Internet to obtain health information; nearly half of Internet users admit that this information influences decisions about their health care and medical treatments. Concurrently, approximately one third of the population uses herbal supplements; a higher percentage is noted for subgroups of cancer patients. The Dietary Supplement Health and Education Act (DSHEA) of 1994 contained regulatory standards for herbal supplements, including restricting any claims for disease prevention, treatment, or cure. This study determined the degree of compliance with the DSHEA, as applied to Internet sites focusing on the subject of herbal supplements and cancer. Internet searches were conducted using six popular search engines and three master search engines in October-December 2000 using the linked terms herb and cancer. The Internet sites identified through this search process were examined for categories of information including claims regarding prevention, treatment, or cure; commercial nature; DSHEA and physician consultation warnings; country of origin; and use of research and testimonials. Additionally, commercial sites were reviewed to identify tactics used to promote products or services. Each of the six primary search engines provided between 11,730 and 58,605 matches for herb and cancer. Further cross matching with the three master search engines identified 70 non-repeating sites that appeared on all three master search engines. Of these 70 sites, nine were irrelevant matches or no longer functioning. Of the remaining 61, 34 (54%) were commercial sites (CS) and 27 (42.8%) were noncommercial sites (NCS). Of the CS surveyed, prevention, treatment, and cure were discussed 92%, 89%, and 58%, respectively. CS provided testimonials, physician consultation recommendations, and DSHEA warnings 89%, 38.8%, and 36.1% of the time, respectively. CS provided research with references 30.6% of the time versus 92.6% of the time in NCS. All international commercial sites surveyed claimed herbal cancer cures. Although the DSHEA was enacted and amended to decrease unlawful claims of disease prevention, treatment, and cure, the results of this study indicate that such claims are prevalent on commercial Internet sites. A majority of sites claim cancer cures through herbal supplementation with little regardfor current regulations, and such claims were more common on sites operated from outside the United States.

Estimating and modelling cure in population-based cancer studies within the framework of flexible parametric survival models.

PubMed

Andersson, Therese M L; Dickman, Paul W; Eloranta, Sandra; Lambert, Paul C

2011-06-22

When the mortality among a cancer patient group returns to the same level as in the general population, that is, the patients no longer experience excess mortality, the patients still alive are considered "statistically cured". Cure models can be used to estimate the cure proportion as well as the survival function of the "uncured". One limitation of parametric cure models is that the functional form of the survival of the "uncured" has to be specified. It can sometimes be hard to find a survival function flexible enough to fit the observed data, for example, when there is high excess hazard within a few months from diagnosis, which is common among older age groups. This has led to the exclusion of older age groups in population-based cancer studies using cure models. Here we have extended the flexible parametric survival model to incorporate cure as a special case to estimate the cure proportion and the survival of the "uncured". Flexible parametric survival models use splines to model the underlying hazard function, and therefore no parametric distribution has to be specified. We have compared the fit from standard cure models to our flexible cure model, using data on colon cancer patients in Finland. This new method gives similar results to a standard cure model, when it is reliable, and better fit when the standard cure model gives biased estimates. Cure models within the framework of flexible parametric models enables cure modelling when standard models give biased estimates. These flexible cure models enable inclusion of older age groups and can give stage-specific estimates, which is not always possible from parametric cure models. © 2011 Andersson et al; licensee BioMed Central Ltd.

Estimating and modelling cure in population-based cancer studies within the framework of flexible parametric survival models

PubMed Central

2011-01-01

Background When the mortality among a cancer patient group returns to the same level as in the general population, that is, the patients no longer experience excess mortality, the patients still alive are considered "statistically cured". Cure models can be used to estimate the cure proportion as well as the survival function of the "uncured". One limitation of parametric cure models is that the functional form of the survival of the "uncured" has to be specified. It can sometimes be hard to find a survival function flexible enough to fit the observed data, for example, when there is high excess hazard within a few months from diagnosis, which is common among older age groups. This has led to the exclusion of older age groups in population-based cancer studies using cure models. Methods Here we have extended the flexible parametric survival model to incorporate cure as a special case to estimate the cure proportion and the survival of the "uncured". Flexible parametric survival models use splines to model the underlying hazard function, and therefore no parametric distribution has to be specified. Results We have compared the fit from standard cure models to our flexible cure model, using data on colon cancer patients in Finland. This new method gives similar results to a standard cure model, when it is reliable, and better fit when the standard cure model gives biased estimates. Conclusions Cure models within the framework of flexible parametric models enables cure modelling when standard models give biased estimates. These flexible cure models enable inclusion of older age groups and can give stage-specific estimates, which is not always possible from parametric cure models. PMID:21696598

Treatment of Giardiasis

PubMed Central

Gardner, Timothy B.; Hill, David R.

2001-01-01

Giardia lamblia is both the most common intestinal parasite in the United States and a frequent cause of diarrheal illness throughout the world. In spite of its recognition as an important human pathogen, there have been relatively few agents used in therapy. This paper discusses each class of drugs used in treatment, along with their mechanism of action, in vitro and clinical efficacy, and side effects and contraindications. Recommendations are made for the preferred treatment in different clinical situations. The greatest clinical experience is with the nitroimidazole drugs, i.e., metronidazole, tinidazole, and ornidazole, which are highly effective. A 5- to 7-day course of metronidazole can be expected to cure over 90% of individuals, and a single dose of tinidazole or ornidazole will cure a similar number. Quinacrine, which is no longer produced in the United States, has excellent efficacy but may be poorly tolerated, especially in children. Furazolidone is an effective alternative but must be administered four times a day for 7 to 10 days. Paromomycin may be used during early pregnancy, because it is not systematically absorbed, but it is not always effective. Patients who have resistant infection can usually be cured by a prolonged course of treatment with a combination of a nitroimidazole with quinacrine. PMID:11148005

A new approach to estimate time-to-cure from cancer registries data.

PubMed

Boussari, Olayidé; Romain, Gaëlle; Remontet, Laurent; Bossard, Nadine; Mounier, Morgane; Bouvier, Anne-Marie; Binquet, Christine; Colonna, Marc; Jooste, Valérie

2018-04-01

Cure models have been adapted to net survival context to provide important indicators from population-based cancer data, such as the cure fraction and the time-to-cure. However existing methods for computing time-to-cure suffer from some limitations. Cure models in net survival framework were briefly overviewed and a new definition of time-to-cure was introduced as the time TTC at which P(t), the estimated covariate-specific probability of being cured at a given time t after diagnosis, reaches 0.95. We applied flexible parametric cure models to data of four cancer sites provided by the French network of cancer registries (FRANCIM). Then estimates of the time-to-cure by TTC and by two existing methods were derived and compared. Cure fractions and probabilities P(t) were also computed. Depending on the age group, TTC ranged from to 8 to 10 years for colorectal and pancreatic cancer and was nearly 12 years for breast cancer. In thyroid cancer patients under 55 years at diagnosis, TTC was strikingly 0: the probability of being cured was >0.95 just after diagnosis. This is an interesting result regarding the health insurance premiums of these patients. The estimated values of time-to-cure from the three approaches were close for colorectal cancer only. We propose a new approach, based on estimated covariate-specific probability of being cured, to estimate time-to-cure. Compared to two existing methods, the new approach seems to be more intuitive and natural and less sensitive to the survival time distribution. Copyright © 2018 Elsevier Ltd. All rights reserved.

Cold-Curing Structural Epoxy Resins: Analysis of the Curing Reaction as a Function of Curing Time and Thickness

PubMed Central

Esposito Corcione, Carola; Freuli, Fabrizio; Frigione, Mariaenrica

2014-01-01

The curing reaction of a commercial cold-curing structural epoxy resin, specifically formulated for civil engineering applications, was analyzed by thermal analysis as a function of the curing time and the sample thickness. Original and remarkable results regarding the effects of curing time on the glass transition temperature and on the residual heat of reaction of the cold-cured epoxy were obtained. The influence of the sample thickness on the curing reaction of the cold-cured resin was also deeply investigated. A highly exothermal reaction, based on a self-activated frontal polymerization reaction, was supposed and verified trough a suitable temperature signal acquisition system, specifically realized for this measurement. This is one of the first studies carried out on the curing behavior of these peculiar cold-cured epoxy resins as a function of curing time and thickness. PMID:28788215

Cold-Curing Structural Epoxy Resins: Analysis of the Curing Reaction as a Function of Curing Time and Thickness.

PubMed

Corcione, Carola Esposito; Freuli, Fabrizio; Frigione, Mariaenrica

2014-09-22

The curing reaction of a commercial cold-curing structural epoxy resin, specifically formulated for civil engineering applications, was analyzed by thermal analysis as a function of the curing time and the sample thickness. Original and remarkable results regarding the effects of curing time on the glass transition temperature and on the residual heat of reaction of the cold-cured epoxy were obtained. The influence of the sample thickness on the curing reaction of the cold-cured resin was also deeply investigated. A highly exothermal reaction, based on a self-activated frontal polymerization reaction, was supposed and verified trough a suitable temperature signal acquisition system, specifically realized for this measurement. This is one of the first studies carried out on the curing behavior of these peculiar cold-cured epoxy resins as a function of curing time and thickness.

Accounting for Cured Patients in Cost-Effectiveness Analysis.

PubMed

Othus, Megan; Bansal, Aasthaa; Koepl, Lisel; Wagner, Samuel; Ramsey, Scott

2017-04-01

Economic evaluations often measure an intervention effect with mean overall survival (OS). Emerging types of cancer treatments offer the possibility of being "cured" in that patients can become long-term survivors whose risk of death is the same as that of a disease-free person. Describing cured and noncured patients with one shared mean value may provide a biased assessment of a therapy with a cured proportion. The purpose of this article is to explain how to incorporate the heterogeneity from cured patients into health economic evaluation. We analyzed clinical trial data from patients with advanced melanoma treated with ipilimumab (Ipi; n = 137) versus glycoprotein 100 (gp100; n = 136) with statistical methodology for mixture cure models. Both cured and noncured patients were subject to background mortality not related to cancer. When ignoring cured proportions, we found that patients treated with Ipi had an estimated mean OS that was 8 months longer than that of patients treated with gp100. Cure model analysis showed that the cured proportion drove this difference, with 21% cured on Ipi versus 6% cured on gp100. The mean OS among the noncured cohort patients was 10 and 9 months with Ipi and gp100, respectively. The mean OS among cured patients was 26 years on both arms. When ignoring cured proportions, we found that the incremental cost-effectiveness ratio (ICER) when comparing Ipi with gp100 was $324,000/quality-adjusted life-year (QALY) (95% confidence interval $254,000-$600,000). With a mixture cure model, the ICER when comparing Ipi with gp100 was $113,000/QALY (95% confidence interval $101,000-$154,000). This analysis supports using cure modeling in health economic evaluation in advanced melanoma. When a proportion of patients may be long-term survivors, using cure models may reduce bias in OS estimates and provide more accurate estimates of health economic measures, including QALYs and ICERs. Copyright © 2017 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

If We Build It, Will They Come? Perceptions of HIV Cure-Related Research by People Living with HIV in Four U.S. Cities: A Qualitative Focus Group Study.

PubMed

Sylla, Laurie; Evans, David; Taylor, Jeff; Gilbertson, Adam; Palm, David; Auerbach, Judith D; Dubé, Karine

2018-01-01

Global interest and investment in the search for an HIV cure has increased. Research has focused on what experts refer to as a sterilizing or eradicating cure, where HIV is eliminated from the body, and on what is often called a functional cure, where HIV remains, kept durably suppressed in the absence of antiretroviral treatment and therapy (ART). Many believe that a functional cure is likely to be found first. HIV cure studies will require active participation by people living with HIV (PLWHIV). Their desires and perceptions will be important to effectively recruit study participants and for the uptake of any future strategy that demonstrates safety and efficacy. The perspectives of PLWHIV are essential to advancing HIV cure research, and they should be taken into consideration as biomedical research advances. We conducted 10 focus groups in four U.S. cities, eliciting perspectives of PLWHIV on HIV cure and cure research. Most participants conceived of a cure as eradicating, and felt favorably toward it. In addition to the physical benefits of a potential cure, participants valued the possible de-stigmatization related to no longer living with HIV, liberation from concerns about transmitting HIV, and freedom from the burden of daily medication. Many participants did not regard a functional cure as an improvement over controlling HIV through ART, were distrustful about viral rebound potential, and noted concerns about medical complications and accompanying psychological distress. Some felt that the risks of HIV cure research were not worth taking. Many were skeptical about science's ability to eliminate HIV from the body.

Effect of short LED lamp exposure on wear resistance, residual monomer and degree of conversion for Filtek Z250 and Tetric EvoCeram composites.

PubMed

Kopperud, Hilde M; Johnsen, Gaute F; Lamolle, Sébastien; Kleven, Inger S; Wellendorf, Hanne; Haugen, Håvard J

2013-08-01

The latest LED dental curing devices claim sufficient curing of restorative materials with short curing times. This study evaluates mechanical and chemical properties as a function of curing time of two commercial composite filling materials cured with three different LED lamps. The composites were Filtek Z250 (3M ESPE) and Tetric EvoCeram (Ivoclar Vivadent) and the LED curing devices were bluephase 16i (Ivoclar Vivadent), L.E.Demetron II (Kerr) and Mini L.E.D. (Satelec). Control samples were cured with a QTH-lamp (VCL 400, Kerr). The wear resistance after simulated tooth brushing, degree of conversion, curing depth, and amounts of residual monomers were measured after different curing times. The results of this study show that short curing time with high-intensity LEDs may influence the bulk properties of the materials, resulting in lower curing depth and increased residual monomer content. The measured surface properties of the materials, degree of conversion and wear resistance, were not affected by short curing times to the same extent. This study demonstrates that reduced exposure time with high intensity LEDs can result in composite restorations with inferior curing depth and increased leaching of monomers. Dentists are recommended to use sufficient curing times even with high intensity LEDs to ensure adequate curing and minimize the risk of monomer leaching. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Influence of turkey meat on residual nitrite in cured meat products.

PubMed

Kilic, B; Cassens, R G; Borchert, L L

2001-02-01

A response surface experimental design was employed to estimate residual nitrite level at various initial nitrite concentrations, percent turkey meat in the formula, and heat quantity (F) values using a typical wiener as the test system. Pork and mechanically separated turkey were used as the meat ingredients. Residual nitrite and pH were measured at day 1, 7 days, 14 days, and 49 days after processing. Protein, fat, salt, moisture, and CIE (L*a*b*) color values were also determined. Results showed that the effect of turkey meat on residual nitrite level was significant (P < 0.01). An increased amount of turkey meat in the formula resulted in lower residual nitrite levels at a fixed pH. The residual nitrite level was initially proportional to initial nitrite concentration, but it became a nonsignificant factor during longer storage time. Differences in heat quantity had a significant effect (P < 0.05) on residual nitrite level initially. Greater heat quantity decreased residual nitrite level in finished cured meat products at a fixed pH. However, this effect became nonsignificant during longer storage. Reduction of residual nitrite in wieners because of turkey meat addition at a fixed pH was due to characteristics of the turkey tissue, but the mechanism of action remains unknown. It was also established that commercial wieners had a higher pH if poultry meat was included in the formulation.

Aqueous film coating to reduce recrystallization of guaifenesin from hot-melt extruded acrylic matrices.

PubMed

Bruce, Caroline D; Fegely, Kurt A; Rajabi-Siahboomi, Ali R; McGinity, James W

2010-02-01

This study investigated the effect of aqueous film coating on the recrystallization of guaifenesin from acrylic, hot-melt extruded matrix tablets. After hot-melt extrusion, matrix tablets were film-coated with either hypromellose or ethylcellulose. The effects of the coating polymer, curing and storage conditions, polymer weight gain, and core guaifenesin concentration on guaifenesin recrystallization were investigated. The presence of either film coating on the guaifenesin-containing tablets was found to prolong the onset time of drug crystallization. The coating polymer was the most important factor determining the delay in the onset of crystallization, with the more hydrophilic polymer, hypromellose, having a higher solubilization potential for the guaifenesin and delaying crystallization for longer period (3 or 6 months in tablets stored at 40 degrees C or 25 degrees C, respectively) than the more hydrophobic ethylcellulose, which displayed a lower solubilization potential for guaifenesin (crystal growth on tablets cured for 2 hours at 60 degrees C occurred within 3 weeks, whereas uncoated tablets displayed surface crystal growth after 30 minutes). Crystal morphology was also affected by the film coating. Elevated temperatures during both curing and storage, incomplete film coalescence, and high core drug concentrations all contributed to an earlier onset of crystal growth.

Cure Cycle Optimization of Rapidly Cured Out-Of-Autoclave Composites.

PubMed

Dong, Anqi; Zhao, Yan; Zhao, Xinqing; Yu, Qiyong

2018-03-13

Out-of-autoclave prepreg typically needs a long cure cycle to guarantee good properties as the result of low processing pressure applied. It is essential to reduce the manufacturing time, achieve real cost reduction, and take full advantage of out-of-autoclave process. The focus of this paper is to reduce the cure cycle time and production cost while maintaining high laminate quality. A rapidly cured out-of-autoclave resin and relative prepreg were independently developed. To determine a suitable rapid cure procedure for the developed prepreg, the effect of heating rate, initial cure temperature, dwelling time, and post-cure time on the final laminate quality were evaluated and the factors were then optimized. As a result, a rapid cure procedure was determined. The results showed that the resin infiltration could be completed at the end of the initial cure stage and no obvious void could be seen in the laminate at this time. The laminate could achieve good internal quality using the optimized cure procedure. The mechanical test results showed that the laminates had a fiber volume fraction of 59-60% with a final glass transition temperature of 205 °C and excellent mechanical strength especially the flexural properties.

Cure Cycle Optimization of Rapidly Cured Out-Of-Autoclave Composites

PubMed Central

Dong, Anqi; Zhao, Yan; Zhao, Xinqing; Yu, Qiyong

2018-01-01

Out-of-autoclave prepreg typically needs a long cure cycle to guarantee good properties as the result of low processing pressure applied. It is essential to reduce the manufacturing time, achieve real cost reduction, and take full advantage of out-of-autoclave process. The focus of this paper is to reduce the cure cycle time and production cost while maintaining high laminate quality. A rapidly cured out-of-autoclave resin and relative prepreg were independently developed. To determine a suitable rapid cure procedure for the developed prepreg, the effect of heating rate, initial cure temperature, dwelling time, and post-cure time on the final laminate quality were evaluated and the factors were then optimized. As a result, a rapid cure procedure was determined. The results showed that the resin infiltration could be completed at the end of the initial cure stage and no obvious void could be seen in the laminate at this time. The laminate could achieve good internal quality using the optimized cure procedure. The mechanical test results showed that the laminates had a fiber volume fraction of 59–60% with a final glass transition temperature of 205 °C and excellent mechanical strength especially the flexural properties. PMID:29534048

Comparison of Depth of Cure, Hardness and Heat Generation of LED and High Intensity QTH Light Sources.

PubMed

Mousavinasab, Sayed Mostafa; Meyers, Ian

2011-07-01

To compare curing performance of a second generation LED curing light with a high power tungsten quartz halogen (QTH). A hybrid composite resin (Filtek Z 250, 3M, USA) was used as test material and cured using a second generation LED light (Translux Power Blue™, Heraus Kulzer ,Germany) or a very high power QTH light unit (EMS, Switzerland). A two split aluminum mold was used to prepare ten samples with LED light source cured for forty seconds and ten samples prepared using high power QTH light unit, cured for four or six seconds recommended exposure time. Hardness, depth of cure (DOC) and thermal rise during exposure time by these light sources were measured. The data submitted to analysis of variance (ANOVA), Tukey's and student's t tests at 5% significance level. Significant differences were found in hardness, DOC of samples cured by above mentioned light sources and also in thermal rises during exposure time. The curing performance of the tested QTH was not as well as the LED light. TPB light source produced the maximum hardness (81.25, 73.29, 65.49,55.83 and 24.53 for 0 mm, 1 mm, 2 mm, 3 mm and 4 mm intervals) and DOC (2.64 mm) values with forty seconds irradiation time and the high power (QTH) the least hardness (73.27, 61.51 and 31.59 for 0 mm, 1 mm and 2 mm, respectively) and DOC (2 mm) values with four seconds irradiation time. Thermal rises during 4 s and 6 s curing time using high power QTH and tested LED were 1.88°C, 3°C and 1.87°C, respectively. The used high power LED light produced greater hardness and depth of cure during forty seconds exposure time compared to high power QTH light with four or six seconds curing time. Thermal rise during 6 s curing time with QTH was greater compared to thermal changes occurred during 40 s curing time with tested LED light source. There was no difference seen in thermal changes caused by LED light with 40 s and QTH light with 4 s exposure time.

Effect of UV curing time on physical and electrical properties and reliability of low dielectric constant materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kao, Kai-Chieh; Cheng, Yi-Lung, E-mail: yjcheng@ncnu.edu.tw; Chang, Wei-Yuan

2014-11-01

This study comprehensively investigates the effect of ultraviolet (UV) curing time on the physical, electrical, and reliability characteristics of porous low-k materials. Following UV irradiation for various periods, the depth profiles of the chemical composition in the low-k dielectrics were homogeneous. Initially, the UV curing process preferentially removed porogen-related CH{sub x} groups and then modified Si-CH{sub 3} and cage Si-O bonds to form network Si-O bonds. The lowest dielectric constant (k value) was thus obtained at a UV curing time of 300 s. Additionally, UV irradiation made porogen-based low-k materials hydrophobic and to an extent that increased with UV curing time.more » With a short curing time (<300 s), porogen was not completely removed and the residues degraded reliability performance. A long curing time (>300 s) was associated with improved mechanical strength, electrical performance, and reliability of the low-k materials, but none of these increased linearly with UV curing time. Therefore, UV curing is necessary, but the process time must be optimized for porous low-k materials on back-end of line integration in 45 nm or below technology nodes.« less

Coating Characterization with the Quartz Crystal Microbalance

NASA Astrophysics Data System (ADS)

Sturdy, Lauren F.

The quartz crystal microbalance is a sensitive tool that can be used to measure the mass, modulus and phase angle of films of appropriate thicknesses. It is can be applied to systems with very varied properties, from liquid to solid, and under many different conditions. In this thesis its capabilities have been used to study the properties of several different systems of relevance to the coatings, art conservation, and rubber communities, in the process of which new techniques and tools were developed to analyze data and improve QCM data collection and experimental design. Alkyd resins, which have been used in artists' paints since the twentieth century, are the subject of the first studies. Alkyds are oil-modified polyesters. These resins are of interest because of their relatively recent use in art and how little is known of the mechanical properties in the early stages of cure. The QCM was shown to be sensitive to the curing process, changes in temperature, and mass change due to exposure to water. Kinetic studies during the first days of curing showed that the curing process can be divided into three regions. The first is dominated by solvent evaporation. In the second, oxygen absorption dominates and the mechanical properties change rapidly. The final stage extends from when the film is touch dry after about a day to years and is characterized by mass loss and continued increases in the modulus. Studying the curing at different temperatures revealed that the reactions do proceed much more rapidly at higher temperatures and an overall energy of activation was calculated for the curing process. The mechanical properties of alkyd resins containing zinc oxide, a white pigment, were studied with the QCM, nanoindentation and dynamic mechanical analysis. These measurements showed increases in the modulus with the inclusion of zinc oxide, and the QCM data showed that the second region started at earlier times as the pigment concentration was increased. Linseed oil is one of the starting materials for many alkyd resins and should cure similarly since the primary curing mechanisms are the same. It takes longer to cure than alkyds because it begins with no initial polymerization. Linseed oil was harder to study, as obtaining even films was difficult, multiple peaks at a single harmonic were observed, and the material properties during the early stages of curing led to a region where viscoelastic properties could not be calculated. To facilitate studying linseed oil, a multiple peak fitting method was developed to extract data from unusual peak shapes. With this ability, measurements at short times could be obtained despite poor film quality. Although linseed oil begins as a softer material than alkyds, its curing follows the same patterns as alkyd resins, exhibiting mass gain followed by mass loss, and sharp increases in modulus and decreases in phase angle during the early stages of curing. Having demonstrated the ability of the QCM to monitor curing, the QCM was also applied to uncrosslinked rubber systems. Rubbers, like the drying oils, contain double bonds which can react with oxygen, so first the oxidation of these materials was studied. In further studies oxidation was undesirable, so protocols were developed to limit oxidation. Measurements were made of homopolymers at different temperatures and the QCM measurements appear to be consistent with time-temperature superposition results obtained at lower frequencies. Blends of the various rubbers were studied and compared with models. The mechanical properties measured by the QCM were between the Voigt and Reuss predictions for most blends studied. Modeling the expected QCM response of layered rubbers matched the predictions of the Reuss model but not the measured values of the rubber blends, suggesting that the QCM is sensitive to different morphologies. Measurements with the QCM expanded our understanding of a variety of systems and proved to be a useful tool to measure mechanical changes during processes which are difficult to study by other methods.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sanders, R.S.

The effects of heat strip time, heat strip temperature, catalyst ratio, mold cure time, post cure time, and post cure temperature on a hybrid (UCC/SE-54/497XL) cellular silicone molding compound are reported.

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. © 2013 Wiley Periodicals, Inc.

[Influence of three-level collaboration network of pediatric burns treatment in Anhui province on treatment effects of burn children].

PubMed

Xia, Z G; Zhou, X L; Kong, W C; Li, X Z; Song, J H; Fang, L S; Hu, D L; Cai, C; Tang, Y Z; Yu, Y X; Wang, C H; Xu, Q L

2018-03-20

Objective: To explore the influence of three-level collaboration network of pediatric burns in Anhui province on treatment effects of burn children. Methods: The data of medical records of pediatric burn children transferred from Lu'an People's Hospital and Fuyang People's Hospital to the First Affiliated Hospital of Anhui Medical University from January 2014 to December 2015 and January 2016 to September 2017 (before and after establishing three-level collaboration network of pediatric burns treatment) were analyzed: percentage of transferred burn children to hospitalized burn children in corresponding period, gender, age, burn degree, treatment method, treatment result, occurrence and treatment result of shock, and operative and non-operative treatment time and cost. Rehabilitation result of burn children transferred back to local hospitals in 2016 and 2017. Data were processed with t test, chi-square test, Mann-Whitney U test, and Fisher's exact test. Results: (1) Percentage of burn children transferred from January 2014 to December 2015 was 34.3% (291/848) of the total number of hospitalized burn children in the same period of time, which was close to 30.4% (210/691) of burn children transferred from January 2016 to September 2017 ( χ (2)=2.672, P >0.05). (2) Gender, age, burn degree, and treatment method of burn children transferred from the two periods of time were close ( χ (2)=3.382, Z =-1.917, -1.911, χ (2)=3.133, P >0.05). (3) Cure rates of children with mild, moderate, and severe burns transferred from January 2016 to September 2017 were significantly higher than those of burn children transferred from January 2014 to December 2015 ( χ (2)=11.777, 6.948, 4.310, P <0.05). Cure rates of children with extremely severe burns transferred from the two periods of time were close ( χ (2)=1.181, P >0.05). (4) Children with mild and moderate burns transferred from the two periods of time were with no shock. The incidence of shock of children with severe burns transferred from January 2014 to December 2015 was 6.0% (4/67), and 3 children among them were cured. The incidence of shock of children with severe burns transferred from January 2016 to September 2017 was 3.9% (2/51), and both children were cured. The incidences and cures of shock of children with severe burns transferred from the two periods of time were close ( χ (2)=0.006, P >0.05). Incidence of shock of children with extremely severe burns transferred from January 2014 to December 2015 was 57.1% (32/56), significantly higher than that of burn children transferred from January 2016 to September 2017 [34.5% (10/29), χ (2)=3.925, P <0.05]. Shock of 25 children with extremely severe burns transferred from January 2014 to December 2015 were cured, and shock of 9 children with extremely severe burns transferred from January 2016 to September 2017 were cured. The cures of shock of children with extremely severe burns transferred from the two periods of time were close ( χ (2)=0.139, P >0.05). (5) Time of operative treatment of children with moderate, severe, and extremely severe burns transferred from January 2014 to December 2015 was obviously longer than that of burn children transferred from January 2016 to September 2017 ( t =2.335, 2.065, 2.310, P <0.05). Time of operative treatment of children with mild burns transferred from the two periods of time was close ( Z =-0.417, P >0.05). Costs of operative treatment of children with moderate and severe burns transferred from January 2014 to December 2015 were significantly more than those of burn children transferred from January 2016 to September 2017 ( Z =-3.324, t =2.167, P <0.05). Costs of operative treatment of children with mild and extremely severe burns transferred from the two periods of time were close ( t =0.627, 0.808, P >0.05). (6)Time of non-operative treatment of children with mild, moderate, and severe burns transferred from January 2014 to December 2015 was obviously longer than that of burn children transferred from January 2016 to September 2017 ( t =2.335, Z =-2.095, t =2.152, P <0.05). Time of non-operative treatment of children with extremely severe burns transferred from the two periods of time was close ( t =0.450, P >0.05). Costs of non-operative treatment of children with moderate and severe burns transferred from January 2014 to December 2015 were obviously higher than those of burn children transferred from January 2016 to September 2017 ( Z =-2.164, t =2.040, P <0.05). Costs of non-operative treatment of children with mild and extremely severe burns transferred from the two periods of time were close ( t =0.146, 1.235, P >0.05). (7) Sixty-seven burn children transferred from January 2016 to September 2017 were transferred back to local hospitals for rehabilitation under the guidance of experts of the First Affiliated Hospital of Anhui Medical University, with 25 patients in 2016 and 42 patients in 2017. Effective rehabilitation rates of burn children transferred back to local hospitals for rehabilitation in 2016 and 2017 were both 100%. Conclusions: The three-level collaboration network of pediatric burns treatment in Anhui province can effectively increase cure rate of children with mild, moderate, and severe burns, reduce incidence of shock of children with extremely severe burns, shorten time of operative treatment of burn children with moderate, severe, and extremely severe burns, and time of non-operative treatment of children with mild, moderate, and severe burns, reduce treatment costs of children with moderate and severe burns, and improve rehabilitation effectiveness of children transferred from Lu'an People's Hospital and Fuyang People's Hospital to the the First Affiliated Hospital of Anhui Medical University.

Improvement of exposure times: effects on adhesive properties and resin-dentin bond strengths of etch-and-rinse adhesives.

PubMed

Ferreira, Sabrina Queji; Costa, Thays Regina; Klein-Júnior, Celso Afonso; Accorinte, Maria de; Meier, Márcia Margarete; Loguercio, Alessandro Dourado; Reis, Alessandra

2011-06-01

This study evaluated the effect of prolonged polymerization times on the microtensile resin-dentin bond strength (μTBS), degree of conversion of adhesive films (DC) and silver nitrate uptake (SNU) for an ethanol/water- (Adper Single Bond 2, [SB]) and an acetone-based (One Step Plus, [OS]) etch-and-rinse adhesive. Thirty caries-free extracted molars were included in this study. The occlusal enamel of all teeth was removed by wet grinding the occlusal enamel on 180-grit SiC paper. Adhesives were applied according to the manufacturer's instructions, but they were light cured for 10, 20 and 40 s at 600 mW/cm2. Bonded sticks (0.6 mm2) were tested in tension (0.5 mm/min). Two bonded sticks from each tooth were immersed in an ammoniacal solution of silver nitrate (24 h), photodeveloped (8 h), and analyzed by SEM. The DC of the adhesives was evaluated under Fourier Transformed Infra-Red spectroscopy (FTIR). Data for each property were analyzed by two-way ANOVA and Tukey's test (α = 0.05). Statistically higher μTBS and DC were observed for SB and OS when both adhesives were light cured for 40 s in comparison with 10 s. For OS, the μTBS in the 20- and 40-s groups did not differ statistically, while for SB it did. Higher prolonged exposure times did not prevent nanoleakage within the hybrid layer for all groups regardless of the adhesive. This study supports the hypothesis that exposure times longer than those recommended can improve the degree of conversion of adhesive films and the immediate resin-dentin bonds. The prolonged curing times (20 and 40 s) for polymerization of simplified adhesives resulted in an increase in the degree of conversion of the adhesive films and resin-dentin bond strengths but did not reduce the nanoleakage within the hybrid layer.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paulauskas, F.L.; Meek, T.T.

Studies of microwave-assisted curing of neat resins (epoxy) and unidirectional glass and carbon fiber laminates have shown that a substantial reduction in the curing time was obtained. This may be explained by the penetration of microwave energy directly and throughout the laminate with enhancement of the kinetics of the chemical reaction. Results of this work indicate that the microwave assisted curing of glass fiber laminates also shows a substantial reduction of the required curing time. Microwave radiation of 2.45 GHz has been demonstrated to be an acceptable method to cure unidirectional carbon fiber laminates. Also, effective curing of crossply (0/90)more » laminates through this method was observed when proper rotation of the parts accompanied the curing process. This is in accordance with previous work. 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. Nevertheless, a moderate reduction in the curing time of these thin laminates was observed due to hybrid curing.« less

Control and reduction of peak temperature in self-curing resins.

PubMed

Schiavetti, R; DE Vico, G; Casucci, A; Covello, F; Ottria, L; Sannino, G; Barlattani, A

2009-07-01

INTRODUCTION.: The aim of this experimental study was to reduce the exothermic reaction during curing of the resins to cold. The significant exotherm generated by the reaction of polymerization of the resin curing involves many clinical complications including the high risk of necrosis against tooth. MATERIAL AND METHODS.: They were used four different types of self curing resins all based on methyl methacrylate, Jet Kit, Major Dentin, Dura Lay, Temporary Cold. The reaction of polymerization of the resins was done in Teflon pans and was monitored by a thermocouple which recorded the highest level reached by each temperature resin with and without additive. The polymerization reaction took place for each resin in the presence of an essential oil, the terpinolene, which acted as a "chain transfer" and different temperatures were recorded. RESULTS.: Resins Dura Lay and Jet kit showed a reduction of very high temperature in the presence of terpinolene, with a statistically significant difference compared to the same reaction without terpinolene Major resin dentin in the presence of the additive has reduced by 8.4°C peak temperature. Resin Temporary Cold has showed benefits with respect to peak temperature, but the reaction was much more 'consistent presence of the additive. DISCUSSION.: The system through which the chain transfer acts to lower the temperature of the reaction is that of chain transfer. Namely that interfere with the reaction of the polymer chains, by transferring these acrylic radicals are no longer active, ie, no longer able to bind to other monomer units, thus avoiding the excessive growth of macromolecules which are those that determine the temperature rise. This leads to the formation of more polymer chains with lower molecular weight.

Inhibition of Listeria monocytogenes growth in cured ready-to-eat meat products by use of sodium benzoate and sodium diacetate.

PubMed

Seman, D L; Quickert, S C; Borger, A C; Meyer, J D

2008-07-01

The effect of sodium benzoate (0.08 to 0.25%) in combination with different concentrations of sodium diacetate (0.05 to 0.15%) and NaClI (0.8 to 2%) and different finished product moisture (55 to 75%) on the growth of Listeria monocytogenes in ready-to-eat meat products was evaluated using a central composite design over 18 weeks of storage at 4 degrees C. The effects of these factors on time to growth were analyzed using a time-to-failure regression method. All main effects were significant except product moisture, which was significant when included in the two- and three-way interactions (P < 0.05). Sodium benzoate was more effective (lengthening time to growth) when used with increasing concentrations of sodium diacetate and salt and decreasing finished product moisture. The model indicated that low-moisture products, e.g., bologna or wieners, could have time-to-growth values longer than 18 weeks if they were formulated with 0.1% sodium benzoate and 0.1% sodium diacetate. Time to growth in high-moisture products, e.g., ham or cured turkey breast at 75% moisture, was predicted to be much shorter for the same basic formulation (0.1% sodium benzoate and 0.1% sodium diacetate). Consequently, high-moisture ready-to-eat products in which sodium benzoate is limited to 0.1% (current standard for generally recognized as safe) may need additional ingredients to effectively inhibit growth of L. monocytogenes.

Flooded Cell Permeation Testing of Elastomers

DTIC Science & Technology

1994-03-01

cured hydrin (EC) elastomer 3. oxide cured neoprene (CR) 4. sulphur cured styrene-butadiene rubber (SBR) 5. sulphur cured nitrile rubber ( NBR ) 6. cured...Road Adelphi, MD 20783-1197 11. SUPPLEMENTARY NOTES Presented at the meeting of the American Chemical Society, Rubber Division, Orlando, Florida, 26 Oct...6 2. Permeation rate-time curve for DMSO through natural rubber ............................... 6 3. Permeation rate-time curve for DMSO through

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

Studies on Poly(propylene fumarate-co-caprolactone diol) Thermoset Composites towards the Development of Biodegradable Bone Fixation Devices

PubMed Central

Jayabalan, M.

2009-01-01

The effect of reinforcement in the cross-linked poly(propylene fumarate-co-caprolactone diol) thermoset composites based on Kevlar fibres and hydroxyapatite was studied. Cross-linked poly(propylene fumarate-co-caprolactone diol) was also studied without any reinforcement for comparison. The reinforcing fibre acts as a barrier for the curing reaction leading to longer setting time and lesser cross-link density. The fibre and HA reinforced composites have almost the same compressive strength. Nonreinforced material undergoes greater degree of swelling. Among the reinforced materials, the hydroxyapatite reinforced composite has a much higher swelling percentage than the fibre reinforced one. The studies on in vitro degradation of the cured materials reveal hydrolytic degradation in Ringer's solution and PBS medium during aging. All the three materials are found to swell initially in Ringer's solution and PBS medium during aging and then undergo gradual degradation. Compression properties of these cross-linked composites increase with aging; HA reinforced composite has the highest compressive strength and compressive modulus, whereas the aged fibre-reinforced composite has the least compressive strength and modulus. PMID:20126578

Studies on Poly(propylene fumarate-co-caprolactone diol) Thermoset Composites towards the Development of Biodegradable Bone Fixation Devices.

PubMed

Jayabalan, M

2009-01-01

The effect of reinforcement in the cross-linked poly(propylene fumarate-co-caprolactone diol) thermoset composites based on Kevlar fibres and hydroxyapatite was studied. Cross-linked poly(propylene fumarate-co-caprolactone diol) was also studied without any reinforcement for comparison. The reinforcing fibre acts as a barrier for the curing reaction leading to longer setting time and lesser cross-link density. The fibre and HA reinforced composites have almost the same compressive strength. Nonreinforced material undergoes greater degree of swelling. Among the reinforced materials, the hydroxyapatite reinforced composite has a much higher swelling percentage than the fibre reinforced one. The studies on in vitro degradation of the cured materials reveal hydrolytic degradation in Ringer's solution and PBS medium during aging. All the three materials are found to swell initially in Ringer's solution and PBS medium during aging and then undergo gradual degradation. Compression properties of these cross-linked composites increase with aging; HA reinforced composite has the highest compressive strength and compressive modulus, whereas the aged fibre-reinforced composite has the least compressive strength and modulus.

Effect of long steam curing durations on the strength of A5 concrete.

DOT National Transportation Integrated Search

1976-01-01

Based on the results of this investigation in which the longest steam curing time was 72 hours, it was concluded that increasing the curing times did not adversely affect the strength of the concrete. However, at the later stages of steam curing, gai...

The Effect of Bridging Locoregional Therapy and Sociodemographics on Survival in Hepatocellular Carcinoma Patients Undergoing Orthotopic Liver Transplantation: A United Network for Organ Sharing Population Study.

PubMed

Magnetta, Michael J; Xing, Minzhi; Zhang, Di; Kim, Hyun S

2016-12-01

To investigate socioeconomic and demographic factors associated with transplantation outcomes in patients with hepatocellular carcinoma (HCC) treated with bridging locoregional therapy (LRT) before orthotopic liver transplantation (OLT). The United Network for Organ Sharing (UNOS) database was used to identify all patients in the United States with HCC who were listed for OLT between 2002 and 2013. Mean overall survival (OS) after OLT was stratified based on age, sex, ethnicity, transplant year, region, and insurance status. Kaplan-Meier estimation was used for survival analysis with log-rank test and Cox proportional hazards model to assess independent prognostic factors for OS. Of the 17,291 listed patients with HCC, 14,511 underwent OLT. Mean age was 57.4 years (76.8% male). Favorable sociodemographic factors were associated with increased rates of bridging LRT before OLT and longer wait time on the transplant list and were shown to be independent prognostic factors for prolonged OS after OLT using multivariate analysis. Favorable demographic factors included patient age < 60 years, donor age < 45 years, year of diagnosis between 2008 and 2013, UNOS regions 4 and 5, Asian ethnicity, high functional status, postgraduate education, private payer insurance, and employment at the time of OLT. Patients with favorable sociodemographics had higher rates of LRT before OLT performed for HCC cure. These patients had longer transplant wait times and longer OS after OLT. Copyright © 2016 SIR. Published by Elsevier Inc. All rights reserved.

Can hepatic resection provide a long-term cure for patients with intrahepatic cholangiocarcinoma?

PubMed

Spolverato, Gaya; Vitale, Alessandro; Cucchetti, Alessandro; Popescu, Irinel; Marques, Hugo P; Aldrighetti, Luca; Gamblin, T Clark; Maithel, Shishir K; Sandroussi, Charbel; Bauer, Todd W; Shen, Feng; Poultsides, George A; Marsh, J Wallis; Pawlik, Timothy M

2015-11-15

A patient can be considered statistically cured from a specific disease when their mortality rate returns to the same level as that of the general population. In the current study, the authors sought to assess the probability of being statistically cured from intrahepatic cholangiocarcinoma (ICC) by hepatic resection. A total of 584 patients who underwent surgery with curative intent for ICC between 1990 and 2013 at 1 of 12 participating institutions were identified. A nonmixture cure model was adopted to compare mortality after hepatic resection with the mortality expected for the general population matched by sex and age. The median, 1-year, 3-year, and 5-year disease-free survival was 10 months, 44%, 18%, and 11%, respectively; the corresponding overall survival was 27 months, 75%, 37%, and 22%, respectively. The probability of being cured of ICC was 9.7% (95% confidence interval, 6.1%-13.4%). The mortality of patients undergoing surgery for ICC was higher than that of the general population until year 10, at which time patients alive without tumor recurrence can be considered cured with 99% certainty. Multivariate analysis demonstrated that cure probabilities ranged from 25.8% (time to cure, 9.8 years) in patients with a single, well-differentiated ICC measuring ≤5 cm that was without vascular/periductal invasion and lymph nodes metastases versus <0.1% (time to cure, 12.6 years) among patients with all 6 of these risk factors. A model with which to calculate cure fraction and time to cure was developed. The cure model indicated that statistical cure was possible in patients undergoing hepatic resection for ICC. The overall probability of cure was approximately 10% and varied based on several tumor-specific factors. Cancer 2015;121:3998-4006. © 2015 American Cancer Society. © 2015 American Cancer Society.

Multifaceted antibiotic treatment analysis of methicillin-sensitive Staphylococcus aureus bloodstream infections.

PubMed

Weber, Zhanni; Ariano, Robert; Lagacé-Wiens, Philippe; Zelenitsky, Sheryl

2016-12-01

Given the overall prevalence and poor prognosis of Staphylococcus aureus bloodstream infections (BSIs), the study of treatment strategies to improve patient outcomes is important. The aim of this study was to conduct a multifaceted antibiotic treatment analysis of methicillin-sensitive S. aureus (MSSA) BSI and to characterise optimal early antibiotic therapy (within the first 7 days of drawing the index blood culture) for this serious infection. Antibiotic selection was categorised as optimal targeted (intravenous cloxacillin or cefazolin), optimal broad (piperacillin/tazobactam or meropenem), adequate (vancomycin) or inadequate (other antibiotics or oral therapy). A TSE (timing, selection, exposure) score was developed to comprehensively characterise early antibiotic therapy, where higher points corresponded to prompt initiation, optimal antibiotic selection and longer exposure (duration). Amongst 71 cases of complicated MSSA-BSI, end-of-treatment (EOT) response (i.e. clinical cure) was improved when at least adequate antibiotic therapy was initiated within 24 h [71.7% (33/46) vs. 48.0% (12/25); P = 0.047]. Clinical cure was also more likely when therapy included ≥4 days of optimal targeted antibiotics within the first 7 days [74.4% (29/39) vs. 50.0% (16/32); P = 0.03]. The TSE score was an informative index of early antibiotic therapy, with EOT cure documented in 72.0% (36/50) compared with 42.9% (9/21) of cases with scores above and below 15.2, respectively (P = 0.02). In multivariable analysis, lower Charlson comorbidity index, presence of BSI on admission, and optimising early antibiotic therapy, as described above, were associated with clinical cure in patients with MSSA-BSI. Copyright © 2016 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.

Efficacy of florfenicol for treatment of clinical and subclinical bovine mastitis.

PubMed

Wilson, D J; Sears, P M; Gonzalez, R N; Smith, B S; Schulte, H F; Bennett, G J; Das, H H; Johnson, C K

1996-04-01

To evaluate efficacy of florfenicol treatment for bovine mastitis caused by Streptococcus agalactiae, Staphylococcus aureus nonagalactiae streptococci, coagulase-negative staphylococci, Escherichia coli, Klebsiella sp, and others. Double blind study with cases randomly assigned to 1 of 2 treatment groups. 861 cows/10 commercial dairy farms. Experimental (750 mg of florfenicol) or control (200 mg of cloxacillin) treatment was administered by intramammary infusion every 12 hours for 3 treatment to all cases. Treatments were randomly assigned identified only by numerical labels. To retain blinding, the longer withdrawal time was adhered to for all cases. Cases remained in the study only if there was no other treatment. Quarter samples were recultured 14, 21, and 28 days later. If all samples after day 1 were culture negative, the case was defined as cured. If only 1 of the follow-up results was positive, the case was considered cured if the day-28 somatic cell count was < 300,000/ ml. Failure of treatment was defined as 2 or more culture positive follow-up samples. Florfenicol and cloxacillin did not differ significantly in efficacy versus clinical (n = 85) or subclinical (n = 71) bovine mastitis, or for any etiologic agent (X2). Overall cure rates for mastitis were: Str agalactiae, 5 of 8 (63%); Sta aureus, 5 of 54 (9%); Streptococcus sp, 16 of 35 (46%); Staphylococcus sp, 7 of 33 (21%); E coli, 5 of 11 (46%); Klebsiella sp, 3 of 6 (50%); others, 1 of 9 (11%); and all cases, 42 of 156 (27%). Florfenicol did not offer any advantage over cloxacillin in efficacy against bovine mastitis. Overall cure rates were low. As with most mastitis treatment regimens poor efficacy may be partly attributable to the short duration of treatment.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paulauskas, F.L.

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 showmore » 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 technology yielded a substantial reduction in the required cure time of these laminates. Multidirectional carbon fiber laminates demonstrated a lack of coupling of VFM energy during the curing process.« less

Effect of insulating concrete forms in concrete compresive strength

NASA Astrophysics Data System (ADS)

Martinez Jerez, Silvio R.

The subject presented in this thesis is the effect of Insulating Concrete Forms (ICF's) on concrete compressive strength. This work seeks to identify if concrete cured in ICF's has an effect in compressive strength due to the thermal insulation provided by the forms. Modern construction is moving to energy efficient buildings and ICF's is becoming more popular in new developments. The thesis used a concrete mixture and a mortar mixture to investigate the effects of ICF's on concrete compressive strength. After the experimentations were performed, it was concluded that the ICF's do affect concrete strength. It was found that the forms increase concrete strength without the need for additional curing water. An increase of 50% in strength at 56 days was obtained. It was concluded that the longer concrete cures inside ICF's, the higher strength it reaches, and that ICF's effect on concrete strength is proportional to volume of concrete.

Advanced manufacturing development of a composite empennage component for L-1011 aircraft

NASA Technical Reports Server (NTRS)

1978-01-01

Work continued toward the development of tooling and processing concepts required for a cocured hat/skin cover assembly. A plan was developed and implemented to develop the process for using preimpregnated T300/5208 with a resin content of 34 + or - 2 percent by weight. Use of this material results in a simplified laminating process because removal by bleeding or prebleeding is no longer required. The approach to this task basically consists of fabricating and testing flat laminated panels and simulated structural panels to verify known processing techniques relative to end-laminate quality. The flat panels were used to determine air bleeding arrangement and required cure cycle. Single and multihat-stiffened panels were fabricated using the established air bleeding arrangement and cure cycle with the resulting cured parts yielding excellent correlation of ply thickness with all surfaces clear of porosity and voids.

HIV Life Cycle

MedlinePlus

... the risk of HIV drug resistance . ART can’t cure HIV, but HIV medicines help people with HIV live longer, healthier lives. ART also reduces the risk of HIV transmission (the spread of HIV to others). HIV attacks and destroys the CD4 cells of the immune system . CD4 cells are a ...

Treatment of cutaneous leishmaniasis with aminosidine (paromomycin) ointment: double-blind, randomized trial in the Islamic Republic of Iran.

PubMed Central

Asilian, A.; Jalayer, T.; Nilforooshzadeh, M.; Ghassemi, R. L.; Peto, R.; Wayling, S.; Olliaro, P.; Modabber, F.

2003-01-01

OBJECTIVE: To compare the parasitological and clinical efficacy of four weeks versus two weeks of treatment with aminosidine (paromomycin) ointment in patients with cutaneous leishmaniasis caused by Leishmania major in the Islamic Republic of Iran. METHODS: Double-blind, randomized trial of four weeks of aminosidine ointment (n = 108) vs two weeks of aminosidine ointment and two weeks of placebo (n = 108). Patients were assessed on days 15, 29, 45, and 105 for clinical cures and clinical and parasitological cures. FINDINGS: Four weeks' treatment gave significantly better cure rates than two weeks' treatment: on day 29, there were 80/108 (74%) vs 64/108 (59%) clinical cures (P = 0.05) and 47 (44%) vs 26 (24%) clinical and parasitological cures (P = 0.005). By day 45, fewer patients who received four weeks' treatment had required rescue treatment with antimonials than those who received two weeks' treatment: 20 (19%) vs 36 (33%) (P = 0.02). On day 105, the results still favoured those who had been allocated four weeks of active treatment, but the differences were no longer as clearly significant. No side-effects were observed or reported. CONCLUSION: Approximately two-thirds of patients given ointment for four weeks were cured clinically. Although about half of those cured might have recovered spontaneously even without treatment, four weeks of aminosidine ointment could become the first-line treatment for uncomplicated cutaneous leishmaniasis due to L. major, with antimonials needed in only the one-third of patients not cured by the end of treatment with aminosidine. This would considerably reduce the costs and side-effects associated with antimonial drugs. PMID:12856053

Hydrothermal solidification of municipal solid waste incineration bottom ash with slag addition.

PubMed

Jing, Zhenzi; Ran, Xianqiang; Jin, Fangming; Ishida, Emile H

2010-01-01

Hydrothermal solidification of municipal solid waste incineration (MSWI) bottom ash has been carried out under saturated steam pressure (1.56 MPa) at 200 degrees C for up to 24 h by mixing quartz, slaked lime and water-cooled blast furnace slag (WBFS). The strength enhancement for the WBFS addition was best. The strength development was shown to be due mainly to tobermorite formation, and the tobermorite formation densified matrix, thus promoting the strength development. WBFS seemed to have a higher reactivity than the quartz during the initial hydrothermal process, which provided more silica available to harden the solidified specimens. However, a longer curing time (24 h) was favorable to the quartz dissolution for tobermorite formation, which in turn, enhanced the strength for quartz addition. Curing time affected the crystal morphology evolution, and the stubby plate of tobermorite seemed to result in a high strength enhancement in this study. Laboratory leaching tests were conducted to determine the amount of heavy metals dissolved from the final solidified specimens, and the leaching results showed that after hydrothermal processing the heavy metals dissolved from the solidified specimens were reduced effectively. As such, the hydrothermal processing may have a high potential for recycling/reusing MSWI ash on a large scale. 2010 Elsevier Ltd. All rights reserved.

PROGNOSTIC FACTORS IN PATIENTS WITH PRESSURE SORES IN A UNIVERSITY HOSPITAL IN SOUTHERN BRAZIL

PubMed Central

WALTER, GUSTAVO PALMEIRO; SEIDEL, WILLIAM; GIUSTINA, RENATA DELLA; BINS-ELY, JORGE; MAURICI, ROSEMERI; NARCISO-SCHIAVON, JANAÍNA LUZ

2017-01-01

ABSTRACT Objective: Despite advances in medical care, patients who are hospitalized or have spinal cord injuries often develop pressure sores. The objective of this study was to describe the epidemiological characteristics of pressure sores and evaluate factors associated with recurrence and cure. Methods: In this historical cohort study, clinical and laboratory data were collected from medical records between 1997 and 2016. Results: Sixty individuals with pressure ulcers were included; mean patient age was 38.1±16.5 (37.0) years, 83.3% were men, and 86.8% identified as white. Most patients (85.1%) had paraplegia, amputation, or trauma of the lower limbs with motor sequelae; the remainder (14.9%) were quadriplegic. Most (78.3%) underwent surgery, and the mean follow-up time was 1.8±2.5 years. The lesions were cured in 25 patients; they recurred in 25% of the patients, and recurrence was seen to be associated with the location of the lesions. Patients with recurrent lesions had more medical consultations and a longer treatment time. Individuals whose ulcers had healed had fewer lesions, higher body mass index (BMI), and a higher proportion of these patients underwent surgery. Conclusions: BMI and location and number of lesions are prognostic factors. Level of Evidence IV, Case Series. PMID:29375252

PROGNOSTIC FACTORS IN PATIENTS WITH PRESSURE SORES IN A UNIVERSITY HOSPITAL IN SOUTHERN BRAZIL.

PubMed

Walter, Gustavo Palmeiro; Seidel, William; Giustina, Renata Della; Bins-Ely, Jorge; Maurici, Rosemeri; Narciso-Schiavon, Janaína Luz

2017-01-01

Despite advances in medical care, patients who are hospitalized or have spinal cord injuries often develop pressure sores. The objective of this study was to describe the epidemiological characteristics of pressure sores and evaluate factors associated with recurrence and cure. In this historical cohort study, clinical and laboratory data were collected from medical records between 1997 and 2016. Sixty individuals with pressure ulcers were included; mean patient age was 38.1±16.5 (37.0) years, 83.3% were men, and 86.8% identified as white. Most patients (85.1%) had paraplegia, amputation, or trauma of the lower limbs with motor sequelae; the remainder (14.9%) were quadriplegic. Most (78.3%) underwent surgery, and the mean follow-up time was 1.8±2.5 years. The lesions were cured in 25 patients; they recurred in 25% of the patients, and recurrence was seen to be associated with the location of the lesions. Patients with recurrent lesions had more medical consultations and a longer treatment time. Individuals whose ulcers had healed had fewer lesions, higher body mass index (BMI), and a higher proportion of these patients underwent surgery. BMI and location and number of lesions are prognostic factors. Level of Evidence IV, Case Series.

Preparation of Microcellular Epoxy Foams through a Limited-Foaming Process: A Contradiction with the Time-Temperature-Transformation Cure Diagram.

PubMed

Wang, Lijun; Zhang, Chun; Gong, Wei; Ji, Yubi; Qin, Shuhao; He, Li

2018-01-01

3D cross-linking networks are generated through chemical reactions between thermosetting epoxy resin and hardener during curing. The curing degree of epoxy material can be increased by increasing curing temperature and/or time. The epoxy material must then be fully cured through a postcuring process to optimize its material characteristics. Here, a limited-foaming method is introduced for the preparation of microcellular epoxy foams (Lim-foams) with improved cell morphology, high thermal expansion coefficient, and good compressive properties. Lim-foams exhibit a lower glass transition temperature (T g ) and curing degree than epoxy foams fabricated through free-foaming process (Fre-foams). Surprisingly, however, the T g of Lim-foams is unaffected by postcuring temperature and time. This phenomenon, which is related to high gas pressure in the bubbles, contradicts that indicated by the time-temperature-transformation cure diagram. High bubble pressure promotes the movement of molecular chains under heating at low temperature and simultaneously suppresses the etherification cross-linking reaction during post-curing. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Network Formation in Piperidine-Cured Epoxy and Epoxy-Rubber Systems: Effects of Cure Time.

NASA Astrophysics Data System (ADS)

D'Oyen, Raquel M.; Carr, Stephen H.

1996-03-01

The system, piperidine-cured diglycidyl ether of bisphenol-A (DGEBA) to which various amounts of carboxyl terminated acrylonitrile-butadiene (CTBN) have been added, is used as a model rubber modified thermoset. The glass transition temperatures (T_g) of a low molecular weight (374 g/eq) epoxy, cured with piperidine at 120 degC, have been measured by differential scanning calorimetry in order to follow the curing process. The maximum Tg is found after curing for 16 hours. Systems that have been modified with varied concentrations of an adducted CTBN, also show Tg maxima at this time. Addition of 5-20in long-time T_gs, indicating complete segregation of the rubber. The T_gs of the CTBN modified systems at short times are higher than in the unmodified epoxy. This acceleration of the initial stage of cure indicates that the CTBN acts as a diluent, increasing the initial rate of reaction by changing the mobility of the reactive sites. The mechanical properties--toughness, yield and modulus--are related to the CTBN content and to the degree of cure of the system.

TVT-O vs TVT: a randomized trial in patients with different degrees of urinary stress incontinence.

PubMed

Araco, F; Gravante, G; Sorge, R; Overton, J; De Vita, D; Sesti, F; Piccione, E

2008-07-01

TVT-O and TVT were compared in patients stratified according the severity of Stress Urinary Incontinence (SUI). Those patients with intrinsic sphincter deficiencies, overactive bladders, associated prolapses, neurovegetative disorders and recurrent SUI or under rehabilitative/medical therapies were all excluded. There were 208 women included. Operating times were longer, and postoperative pain greater for TVT (p < 0.001). TVT produced longer hospitalizations in severe SUI patients (p < 0.001). After 1 year of follow-up, incontinence was cured in all mild SUI patients with both techniques, in all severe SUI patients when treated with TVT and in 66% of them when treated with TVT-O (p < 0.001). Vaginal perforations occurred during the TVT-O (p = 0.01), bladder perforations during TVT (p = NS), bladder obstructions in mild SUI patients after TVT (p < 0.001). The severity of SUI is an important parameter that influences results after TVT-O and TVT, and could be used to guide surgeons in selecting the most effective intervention.

Extended Infusion of Piperacillin/Tazobactam in Children.

PubMed

Knoderer, Chad A; Karmire, Lauren C; Andricopulos, Katie L; Nichols, Kristen R

2017-01-01

Extended-infusion piperacillin/tazobactam (TZP) has been associated with positive clinical outcomes in adults, but similar data in children are lacking. The objective of this study was to describe efficacy outcomes with pediatric patients receiving extended-infusion TZP. This was a retrospective case series of children aged 1 month to 17 years who had documented Gram-negative infection and received extended-infusion TZP between April 2011 and March 2012. The primary outcome was 21-day clinical cure defined as negative follow-up cultures, where available, and infection resolution. Fifty children with a median (interquartile range [IQR]) age of 5 (2-9) years were included in the study. Patients received a median (IQR) TZP dose of 111.4 (100-112.5) mg/kg administered every 8 hours over 4 hours. Clinical and microbiologic cure were observed in 74% and 100% of patients, respectively. Patients not meeting criterial for 21-day clinical cure were younger (1 vs 7 years, p = 0.087) and had a longer length of hospital stay (23 vs 11 days, p = 0.037). The majority of children in this cohort achieved 21-day clinical cure with extended-interval TZP. Those without clinical cure tended to be younger and critically ill. Additional comparative studies evaluating traditional and extended-infusion TZP in children are needed.

Cure modeling in real-time prediction: How much does it help?

PubMed

Ying, Gui-Shuang; Zhang, Qiang; Lan, Yu; Li, Yimei; Heitjan, Daniel F

2017-08-01

Various parametric and nonparametric modeling approaches exist for real-time prediction in time-to-event clinical trials. Recently, Chen (2016 BMC Biomedical Research Methodology 16) proposed a prediction method based on parametric cure-mixture modeling, intending to cover those situations where it appears that a non-negligible fraction of subjects is cured. In this article we apply a Weibull cure-mixture model to create predictions, demonstrating the approach in RTOG 0129, a randomized trial in head-and-neck cancer. We compare the ultimate realized data in RTOG 0129 to interim predictions from a Weibull cure-mixture model, a standard Weibull model without a cure component, and a nonparametric model based on the Bayesian bootstrap. The standard Weibull model predicted that events would occur earlier than the Weibull cure-mixture model, but the difference was unremarkable until late in the trial when evidence for a cure became clear. Nonparametric predictions often gave undefined predictions or infinite prediction intervals, particularly at early stages of the trial. Simulations suggest that cure modeling can yield better-calibrated prediction intervals when there is a cured component, or the appearance of a cured component, but at a substantial cost in the average width of the intervals. Copyright © 2017 Elsevier Inc. All rights reserved.

Effect of post cure time and temperature on the properties of two phenolic-fiber composites

NASA Technical Reports Server (NTRS)

Lucy, M. H.; Price, H. L.

1975-01-01

Some effects of post-cure time and temperature on the physicomechanical properties of a phenolic-asbestos and a phenolic-glass composite are studied. The molding and post-curing procedures are discussed along with physical and mechanical test results. It is found that the specific gravity of the panels tested decreased slightly but the hardness always increased with post cure, and that the mechanical properties had different patterns of response to increasing post-cure time and temperature. For tensile properties, strength decreased, modulus increased, and elongation at break exhibited little change. In general, the phenolic-asbestos showed more positive response to post cure than did the phenolic-glass. Mold venting is found to impart better properties to the composites concerned.

Long-term follow-up of bulking agents for stress urinary incontinence in older patients.

PubMed

Plotti, Francesco; Montera, Roberto; Terranova, Corrado; Luvero, Daniela; Marrocco, Francesca; Miranda, Andrea; Gatti, Alessandra; De Cicco Nardone, Carlo; Angioli, Roberto; Scaletta, Giuseppe

2018-06-01

Implantation of bulking agents represents a noninvasive procedure for the treatment of stress urinary incontinence (SUI) in all patients where a more invasive procedure may increase perioperative risks. The primary aim of this retrospective study was to evaluate the efficacy over time of bulking agent implantation. As secondary aims, we evaluated long-term (patients' subjective) satisfaction rate, rate of de novo urinary symptoms, and the impact of urinary incontinence on the quality of life. All patients who underwent implantation of bulking agents between 1999 and 2013 at Campus Bio-Medico of Rome were retrospectively considered eligible for this study. Patients were interviewed using two standardized questionnaires: International Consultation on Incontinence Questionnaire Short Form and Patient Global Impression of Improvement. Cure rate, improvement rate, failure rate, and the onset of new symptoms were also investigated through specific questions. The original group of patients was then divided into two subgroups according to follow-up time (group A: shorter than median follow-up; group B: longer than median follow-up). Sixty-three patients were enrolled. Mean follow-up was 8.3 ± 3.5 years with a range of 3.5 to 18 years. Fifteen (24%) cured patients (cure rate), 12 (19%) improved patients (improvement rate), 36 (57%) failed treatment (failure rate). We reported an overall success rate of 43%. No differences were reported among groups in terms of overall success rate (42% vs 44% for group A and group B, respectively). Bulking agent implantation is an effective treatment for people with intrinsic sphincter deficiency (type III SUI) and it is a valid alternative to more invasive surgeries in older patients. Moreover, it shows an overall success rate (43%) that remains high even after many years.

Argon Ion Laser Polymerized Acrylic Resin: A Comparative Analysis of Mechanical Properties of Laser Cured, Light Cured and Heat Cured Denture Base Resins

PubMed Central

Murthy, S Srinivasa; Murthy, Gargi S

2015-01-01

Background: Dentistry in general and prosthodontics in particular is evolving at greater pace, but the denture base resins poly methyl methacrylate. There has been vast development in modifying chemically and the polymerization techniques for better manipulation and enhancement of mechanical properties. One such invention was introduction of visible light cure (VLC) denture base resin. Argon ion lasers have been used extensively in dentistry, studies has shown that it can polymerize restorative composite resins. Since composite resin and VLC resin share the same photo initiator, Argon laser is tested as activator for polymerizing VLC resin. In the Phase 1 study, the VLC resin was evaluated for exposure time for optimum polymerization using argon ion laser and in Phase 2; flexural strength, impact strength, surface hardness and surface characteristics of laser cured resin was compared with light cure and conventional heat cure resin. Materials and Methods: Phase 1; In compliance with American Dental Association (ADA) specification no. 12, 80 samples were prepared with 10 each for different curing time using argon laser and evaluated for flexural strength on three point bend test. Results were compared to established performance requirement specified. Phase 2, 10 specimen for each of the mechanical properties (30 specimen) were polymerized using laser, visible light and heat and compared. Surface and fractured surface of laser, light and heat cured resins were examined under scanning electron microscope (SEM). Results: In Phase 1, the specimen cured for 7, 8, 9 and 10 min fulfilled ADA requirement. 8 min was taken as suitable curing time for laser curing. Phase 2 the values of mechanical properties were computed and subjected to statistical analysis using one-way ANOVA and Tukey post-hoc test. The means of three independent groups showed significant differences between any two groups (P < 0.001). Conclusion: Triad VLC resin can be polymerized by argon ion laser with 1 W/mm2 power and exposure time of 8 min to satisfy ADA specification. Impact strength, surface hardness of laser cure was better than light cure and heat cure resin. Flexural strength of light cure was better than laser cure and heat cure resin. The SEM study showed similar density on surface, the fractured surface of heat cure resin was dense and compact. PMID:26124596

Willingness to participate and take risks in HIV cure research: survey results from 400 people living with HIV in the US.

PubMed

Dubé, Karine; Evans, David; Sylla, Laurie; Taylor, Jeff; Weiner, Bryan J; Skinner, Asheley; Thirumurthy, Harsha; Tucker, Joseph D; Rennie, Stuart; Greene, Sandra B

2017-01-01

Participation in early-phase HIV cure studies includes clinical risks with little to no likelihood of clinical benefit. Examining the willingness of people living with HIV to participate is important to guide study design and informed consent. Our study examined the overall willingness of people living with HIV to participate in HIV cure research in the US, focusing on perceived risks and benefits of participation. We undertook an online survey of adults living with HIV in the US. Survey questions were developed based on previous research and a scoping review of the literature. We quantitatively assessed individuals' perceived risks and benefits of HIV cure-related research and respondents' willingness to participate in different modalities of HIV cure studies. We recruited 409 study participants of whom 400 were eligible for the study and were included in the analysis (nine were not eligible due to self-declared HIV-negative status). We found >50% willingness to participate in 14 different types of HIV cure studies. Perceived clinical benefits and social benefits were important motivators, while personal clinical risks appeared to deter potential participation. Roughly two-thirds of survey respondents (68%) indicated that they were somewhat willing to stop treatment as part of HIV cure research. In the bivariate models, females, African Americans/blacks, Hispanics, individuals in the lowest income bracket, people living with HIV for longer periods of their lives, and people who were self-perceived 'very healthy' were less willing to participate in certain types of HIV cure studies than others. Multivariate results showed the perceived benefits (adjusted odds ratios >1) and perceived risks (adjusted odds ratios <1) acted as potential motivators and deterrents to participation, respectively. Our study is the first attempt to quantify potential motivators and deterrents of participation in HIV cure research in the US using perceived risks and benefits. The results offer guidance to HIV cure researchers and developers of interventions about the beneficial and detrimental characteristics of HIV cure strategies that are most meaningful to people living with HIV. The study also highlights new potential lines of inquiry for further social science and ethics research.

Cationic cure kinetics of a polyoxometalate loaded epoxy nanocomposite

DOE Office of Scientific and Technical Information (OSTI.GOV)

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 atmore » 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.« less

Efficacy of intramammary tilmicosin and risk factors for cure of Staphylococcus aureus infection in the dry period.

PubMed

Dingwell, R T; Leslie, K E; Duffield, T F; Schukken, Y H; DesCoteaux, L; Keefe, G P; Kelton, D F; Lissemore, K D; Shewfelt, W; Dick, P; Bagg, R

2003-01-01

The objective ofthis study was to evaluate the efficacy of intramammary tilmicosin, administered at drying-off, for eliminating Staphylococcus aureus infection, and to identify risk factors for S. aureus cure during the dry period. A total of 219 naturally infected cows, representing 308 quarters, were randomized to receive either one of two treatments at drying-off. Cows received either an intramammary infusion of 500 mg of benzathine cloxacillin, or a sterile solution containing 1,500 mg of tilmicosin. All cows had quarter milk samples taken aseptically three times before dry-off, and at wk 1, 2, and 4 of the subsequent lactation. Overall, 62% of cows and 67.5% of quarters infected with S. aureus cured during the dry period. The cure following administraton of tilmicosin was 67.3 and 72.5% for cows and quarters, respectively. By comparison, the cure achieved with cloxacillin was 56.9 and 62.9% of cows and quarters. Cows receiving tilmicosin were 2.1 times more likely to cure. The cure rate for cows decreased as the linear score on the last DHI test increased, and as the amount of S. aureus being shed increased. Quarters that cultured positive multiple times before drying-off were less likely to cure. Staphylococcus aureus infections located in front quarters of the udder were 2 times more likely to cure than those in hind quarters. Results of this study demonstrate that intramammary tilmicosin at drying-off is efficacious in curing existing S. aureus during the dry period. Risk factors associated with the cure of S. aureus were identified.

A CpG island methylator phenotype in acute myeloid leukemia independent of IDH mutations and associated with a favorable outcome

PubMed Central

Kelly, Andrew D.; Kroeger, Heike; Yamazaki, Jumpei; Taby, Rodolphe; Neumann, Frank; Yu, Sijia; Lee, Justin T.; Patel, Bela; Li, Yuesheng; He, Rong; Liang, Shoudan; Lu, Yue; Cesaroni, Matteo; Pierce, Sherry A.; Kornblau, Steven M.; Bueso-Ramos, Carlos E.; Ravandi, Farhad; Kantarjian, Hagop M.; Jelinek, Jaroslav; Issa, Jean-Pierre J.

2016-01-01

Genetic changes are infrequent in acute myeloid leukemia (AML) compared to other malignancies and often involve epigenetic regulators, suggesting that an altered epigenome may underlie AML biology and outcomes. In 96 AML cases including 65 pilot samples selected for cured/not-cured, we found higher CpG island (CGI) promoter methylation in cured patients. Expanded genome-wide digital restriction enzyme analysis of methylation (DREAM) data revealed a CGI methylator phenotype independent of IDH1/2 mutations we term AML-CIMP (A-CIMP+). A-CIMP was associated with longer overall survival (OS) in this dataset (median OS, years: A-CIMP+ = Not reached, A-CIMP− =1.17; P=0.08). For validation we used 194 samples from The Cancer Genome Atlas interrogated with Illumina 450k methylation arrays where we confirmed longer OS in A-CIMP (median OS, years: A-CIMP+ =2.34, A-CIMP− =1.00; P=0.01). Hypermethylation in A-CIMP favored CGIs (OR: CGI/non-CGI=5.21), and while A-CIMP was enriched in CEBPA (P=0.002) and WT1 mutations (P=0.02), 70% of cases lacked either mutation. Hypermethylated genes in A-CIMP function in pluripotency maintenance, and a gene expression signature of A-CIMP was associated with outcomes in multiple datasets. We conclude that CIMP in AML cannot be explained solely by gene mutations (e.g. IDH1/2, TET2), and that curability in A-CIMP+ AML should be validated prospectively. PMID:28074068

A CpG island methylator phenotype in acute myeloid leukemia independent of IDH mutations and associated with a favorable outcome.

PubMed

Kelly, A D; Kroeger, H; Yamazaki, J; Taby, R; Neumann, F; Yu, S; Lee, J T; Patel, B; Li, Y; He, R; Liang, S; Lu, Y; Cesaroni, M; Pierce, S A; Kornblau, S M; Bueso-Ramos, C E; Ravandi, F; Kantarjian, H M; Jelinek, J; Issa, J-Pj

2017-10-01

Genetic changes are infrequent in acute myeloid leukemia (AML) compared with other malignancies and often involve epigenetic regulators, suggesting that an altered epigenome may underlie AML biology and outcomes. In 96 AML cases including 65 pilot samples selected for cured/not-cured, we found higher CpG island (CGI) promoter methylation in cured patients. Expanded genome-wide digital restriction enzyme analysis of methylation data revealed a CGI methylator phenotype independent of IDH1/2 mutations we term AML-CGI methylator phenotype (CIMP) (A-CIMP + ). A-CIMP was associated with longer overall survival (OS) in this data set (median OS, years: A-CIMP + =not reached, CIMP - =1.17; P=0.08). For validation we used 194 samples from The Cancer Genome Atlas interrogated with Illumina 450k methylation arrays where we confirmed longer OS in A-CIMP (median OS, years: A-CIMP + =2.34, A-CIMP - =1.00; P=0.01). Hypermethylation in A-CIMP + favored CGIs (OR: CGI/non-CGI=5.21), and while A-CIMP + was enriched in CEBPA (P=0.002) and WT1 mutations (P=0.02), 70% of cases lacked either mutation. Hypermethylated genes in A-CIMP + function in pluripotency maintenance, and a gene expression signature of A-CIMP was associated with outcomes in multiple data sets. We conclude that CIMP in AML cannot be explained solely by gene mutations (for example, IDH1/2, TET2), and that curability in A-CIMP + AML should be validated prospectively.

Slide Rule For Calculating Curing Schedules

NASA Technical Reports Server (NTRS)

Heater, Don

1995-01-01

Special-purpose slide rule devised for calculating schedules for storing and curing adhesives, sealants, and other materials characterized by known curing times and shelf lives. Prevents mistakes commonly made in determining storage and curing schedules.

Differential Curing In Fiber/Resin Laminates

NASA Technical Reports Server (NTRS)

Webster, Charles N.

1989-01-01

Modified layup schedule counteracts tendency toward delamination. Improved manufacturing process resembles conventional process, except prepregs partially cured laid on mold in sequence in degree of partial cure decreases from mold side to bag side. Degree of partial cure of each layer at time of layup selected by controlling storage and partial-curing temperatures of prepreg according to Arrhenius equation for rate of gel of resin as function of temperature and time from moment of mixing. Differential advancement of cure in layers made large enough to offset effect of advance bag-side heating in oven or autoclave. Technique helps prevent entrapment of volatile materials during manufacturing of fiber/resin laminates.

Methods for analysis of the occurrence of abscess in patients with pancreatitis.

PubMed

Roca-Antonio, J; Escudero, L E; Gener, J; Oller, B; Rodríguez, N; Muñoz, A

1997-01-01

Standard survival analysis methods are useful for data involving censored cases when cures do not generally occur. If the object is to study, for instance, the development of a complication in the progress of an infectious disease, some people may be cured before complications develop. In this article, we provide methods for the analysis of data when cures do occur. An example is a study of prognostic factors for pancreatic abscess in patients with pancreatitis, some of whom leave the risk set because the pancreatitis clears. We present methods for estimating the survival curves and comparing hazard function for two objectives: (1) the occurrence of an abscess, irrespective of whether the patients are cured or not, and (2) the occurrence of an abscess for patients who, at that stage, have not been cured. We illustrate the applications of the methods using a sample of 50 patients with severe pancreatitis. To study the occurrence of an abscess, regardless of whether the patients are cured or not, we show that the appropriate strategy is to assign to the cured patients an infinite time to the appearance of an abscess. If the cured were considered censored at the moment the pancreatitis cleared, this would result in an overestimation of the hazard of presenting an abscess. On the other hand, if the objective is to compare the occurrence of abscess according to an exposure for patients who have not been cured, one needs to censor the cured patients at the time they are cured. For the analysis of survival data in the context of infectious diseases when cure is possible, it is important to use a censoring strategy that is pertinent to the specific aims of the study. Considering cures as censored at the time of cure is not always appropriate.

Analysis of curing of a sustained release coating formulation by application of NIR spectroscopy to monitor changes associated with glyceryl monostearate.

PubMed

Howland, Harris; Fahmy, Raafat; Hoag, Stephen W

2015-01-01

For controlled release, latex or pseudolatex coatings to function as designed, it must be cured at temperatures at or slightly above the polymer's glass transition temperature. The focus of this study is to develop an understanding of the curing process and to develop near infrared spectroscopy as a tool for monitoring curing. Differential scanning calorimetry studies were used to determine how the thermal properties of glyceryl monostearate (GMS) and its polymorphic forms relate to the extent of Eudragit® polymer coat curing at different curing temperatures. The different GMS melting endotherms were used to monitor the extent of curing and as references for model development. The calculated melting peak areas for the GMS were plotted versus time and found to be dependent on time and temperature used for curing. Principal component analysis and parallel factor analysis were used to investigate the effect of curing on the films and showed that spectral changes could be could be directly related to the changes associated with the GMS during curing. Partial least square models developed could predict the extent of curing and the final state of GMS post curing.

Post-irradiation hardening of dual-cured and light-cured resin cements through machinable ceramics.

PubMed

Yoshida, Keiichi; Atsuta, Mitsuru

2006-10-01

To evaluate the surface hardness (Knoop Hardness Number) of the thin layer in three light-cured and dual-cured resin cements irradiated through or not through 2.0 mm thick machinable ceramics. A piece of adhesive polyethylene tape with a circular hole was positioned on the surface of the ceramic plate to control the cement layer (approximately 50 microm). The cement paste was placed on the ceramic surface within the circle. The ceramic plate with resin cement paste was placed on a clear micro cover glass over a zirconia ceramic block to obtain a flat surface, and the material was polymerized using a visible-light-curing unit. The surface hardness was recorded at a series of time intervals up to 5 days, starting from the end of a light-irradiation period. The hardness steadily increased with post-irradiation time and tended towards a maximum, usually reached after 1 or 2 days. In all cases, the increase in hardness was relatively rapid over the first 30 minutes and continued at a lower rate thereafter. The dual-cured resin cement for each material showed a significantly higher hardness value than the light-cured resin cement irradiated either through or not through ceramics at all post-irradiation times. The resin cements cured through ceramic for each material were significantly less hard compared with those cured not through ceramics at all post-irradiation times.

A flexible cure rate model with dependent censoring and a known cure threshold.

PubMed

Bernhardt, Paul W

2016-11-10

We propose a flexible cure rate model that accommodates different censoring distributions for the cured and uncured groups and also allows for some individuals to be observed as cured when their survival time exceeds a known threshold. We model the survival times for the uncured group using an accelerated failure time model with errors distributed according to the seminonparametric distribution, potentially truncated at a known threshold. We suggest a straightforward extension of the usual expectation-maximization algorithm approach for obtaining estimates in cure rate models to accommodate the cure threshold and dependent censoring. We additionally suggest a likelihood ratio test for testing for the presence of dependent censoring in the proposed cure rate model. We show through numerical studies that our model has desirable properties and leads to approximately unbiased parameter estimates in a variety of scenarios. To demonstrate how our method performs in practice, we analyze data from a bone marrow transplantation study and a liver transplant study. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Polymerization of a dual-cured cement through ceramic: LED curing light vs halogen lamp.

PubMed

Lopes, Lawrence Gonzaga; Franco, Eduardo Batista; Name Neto, Abrão; Herrera, Francyle S; Kurachi, Cristina; Castañeda-Espinosa, Juan C; Lauris, José Roberto Pereira

2004-12-01

The aim of this study was to investigate the influence of light source, LED unit and halogen lamp (HL), on the effectiveness of Enforce dual-cured cement cured under a ceramic disc. Three exposure times (60, 80 and 120 s) were also evaluated. Two experimental groups, in which the polymerization of the dual-cured cement was performed through a ceramic disc, and two control groups, in which the polymerization of the dual-cured cement was performed directly without presence of ceramic disc were subdivided into three subgroups (three different exposure times), with five specimens each: G1A- HL 60s; G1B- HL 80s; G1C- HL 120s; G2A- LED 60s; G2B- LED 80s; G2C- LED 120s; and control groups: G3A- HL 60s; G3B- HL 80s; G3C- HL 120s; G4A- LED 60s; G4B- LED 80s and G4C- LED 120s. Cement was applied in a steel matrix (4mm diameter, 1.2mm thickness). In the experimental groups, a ceramic disc was placed on top. The cement was light-cured through the ceramic by a HL and LED, however, the control groups were cured without the ceramic disc. The specimens were stored in a light-proof container at 37ºC for 24 hours, then Vickers hardness was determined. A four-way ANOVA and Tukey test (p£ 0.05) were performed. All specimens cured by LED for 60s showed inferior values compared with the halogen groups. In general, light-curing by LED for 80s and 120s was comparable to halogen groups (60s and 80s) and their control groups. LED technology can be viable for light-curing through conventional ceramic indirect restorations, when curing time is increased in relation to HL curing time.

Biological Course-Based Undergraduate Research Experiences: An Examination of an Introductory Level Implementation

NASA Astrophysics Data System (ADS)

Knoth, Kenneth Charles

Course-based undergraduate research experiences (CUREs) provide authentic research benefits to an entire laboratory course population. CURE experiences are proposed to enhance research skills, critical thinking, productivity, and retention in science. CURE curriculum developers face numerous obstacles, such as the logistics and time commitment involved in bringing a CURE to larger student populations. In addition, an ideal CURE topic requires affordable resources, lab techniques that can be quickly mastered, time for multiple iterations within one semester, and the opportunity to generate new data. This study identifies some of the CURE activities that lead to proposed participant outcomes. Introductory Biology I CURE lab students at Southern Illinois University Edwardsville completed research related to the process of converting storage lipids in microalgae into biodiesel. Data collected from CURE and traditional lab student participants indicate increased CURE student reports of project ownership, scientific self-efficacy, identification as a scientist, and sense of belonging to a science community. Study limitations and unanticipated benefits are discussed.

7 CFR 58.412 - Coolers or curing rooms.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 3 2012-01-01 2012-01-01 false Coolers or curing rooms. 58.412 Section 58.412....412 Coolers or curing rooms. Coolers or curing rooms where cheese is held for curing or storage shall... times. The shelves shall be kept clean and dry. This does not preclude the maintenance of suitable...

7 CFR 58.412 - Coolers or curing rooms.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 3 2014-01-01 2014-01-01 false Coolers or curing rooms. 58.412 Section 58.412....412 Coolers or curing rooms. Coolers or curing rooms where cheese is held for curing or storage shall... times. The shelves shall be kept clean and dry. This does not preclude the maintenance of suitable...

7 CFR 58.412 - Coolers or curing rooms.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 3 2013-01-01 2013-01-01 false Coolers or curing rooms. 58.412 Section 58.412....412 Coolers or curing rooms. Coolers or curing rooms where cheese is held for curing or storage shall... times. The shelves shall be kept clean and dry. This does not preclude the maintenance of suitable...

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....412 Coolers or curing rooms. Coolers or curing rooms where cheese is held for curing or storage shall... times. The shelves shall be kept clean and dry. This does not preclude the maintenance of suitable...

7 CFR 58.412 - Coolers or curing rooms.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 3 2011-01-01 2011-01-01 false Coolers or curing rooms. 58.412 Section 58.412....412 Coolers or curing rooms. Coolers or curing rooms where cheese is held for curing or storage shall... times. The shelves shall be kept clean and dry. This does not preclude the maintenance of suitable...

A comparative study of mixture cure models with covariate

NASA Astrophysics Data System (ADS)

Leng, Oh Yit; Khalid, Zarina Mohd

2017-05-01

In survival analysis, the survival time is assumed to follow a non-negative distribution, such as the exponential, Weibull, and log-normal distributions. In some cases, the survival time is influenced by some observed factors. The absence of these observed factors may cause an inaccurate estimation in the survival function. Therefore, a survival model which incorporates the influences of observed factors is more appropriate to be used in such cases. These observed factors are included in the survival model as covariates. Besides that, there are cases where a group of individuals who are cured, that is, not experiencing the event of interest. Ignoring the cure fraction may lead to overestimate in estimating the survival function. Thus, a mixture cure model is more suitable to be employed in modelling survival data with the presence of a cure fraction. In this study, three mixture cure survival models are used to analyse survival data with a covariate and a cure fraction. The first model includes covariate in the parameterization of the susceptible individuals survival function, the second model allows the cure fraction to depend on covariate, and the third model incorporates covariate in both cure fraction and survival function of susceptible individuals. This study aims to compare the performance of these models via a simulation approach. Therefore, in this study, survival data with varying sample sizes and cure fractions are simulated and the survival time is assumed to follow the Weibull distribution. The simulated data are then modelled using the three mixture cure survival models. The results show that the three mixture cure models are more appropriate to be used in modelling survival data with the presence of cure fraction and an observed factor.

Practical application of cure mixture model for long-term censored survivor data from a withdrawal clinical trial of patients with major depressive disorder.

PubMed

Arano, Ichiro; Sugimoto, Tomoyuki; Hamasaki, Toshimitsu; Ohno, Yuko

2010-04-23

Survival analysis methods such as the Kaplan-Meier method, log-rank test, and Cox proportional hazards regression (Cox regression) are commonly used to analyze data from randomized withdrawal studies in patients with major depressive disorder. However, unfortunately, such common methods may be inappropriate when a long-term censored relapse-free time appears in data as the methods assume that if complete follow-up were possible for all individuals, each would eventually experience the event of interest. In this paper, to analyse data including such a long-term censored relapse-free time, we discuss a semi-parametric cure regression (Cox cure regression), which combines a logistic formulation for the probability of occurrence of an event with a Cox proportional hazards specification for the time of occurrence of the event. In specifying the treatment's effect on disease-free survival, we consider the fraction of long-term survivors and the risks associated with a relapse of the disease. In addition, we develop a tree-based method for the time to event data to identify groups of patients with differing prognoses (cure survival CART). Although analysis methods typically adapt the log-rank statistic for recursive partitioning procedures, the method applied here used a likelihood ratio (LR) test statistic from a fitting of cure survival regression assuming exponential and Weibull distributions for the latency time of relapse. The method is illustrated using data from a sertraline randomized withdrawal study in patients with major depressive disorder. We concluded that Cox cure regression reveals facts on who may be cured, and how the treatment and other factors effect on the cured incidence and on the relapse time of uncured patients, and that cure survival CART output provides easily understandable and interpretable information, useful both in identifying groups of patients with differing prognoses and in utilizing Cox cure regression models leading to meaningful interpretations.

Elucidation of the Cross-Link Structure of Nadic-End-Capped Polyimides Using NMR of C-13-Labeled Polymers

NASA Technical Reports Server (NTRS)

Meador, Mary Ann B.; Johnston, J. Christopher; Cavano, Paul J.

1997-01-01

Solid NMR of C-13 isotope-labeled samples of PMR-15 was used to follow the cross-linking reaction of the nadic end cap. Some samples were labeled on one of the carbon atoms of the nadic end cap, and others on the methylene carbon atom of the methylenedianiline portion of the polymer. NMR spectra were run on these samples both before and after cross-linking. In this way, direct evidence of the major products of cross-linking under normal cure conditions is provided. The majority (approximately 85%) of the cross-linking derives from olefin polymerization through the double bond of the end cap. Approximately 15% of the products could come from a pathway involving a retro-Diels-Alder reaction. However, all of the products could be explained by a biradical intermediate without a retro-Diels-Alder reaction. Evidence is also presented that the methylene moiety in the methylenedianiline part of the polymer chain also participates in the cross-linking, albeit to a small extent, by a radical transfer reaction. Different cure conditions (higher temperatures, longer times) could change the relative distribution of the products.

Research of Cemented Paste Backfill in Offshore Environments

NASA Astrophysics Data System (ADS)

Wang, Kun; Yang, Peng; Lyu, Wensheng; Lin, Zhixiang

2018-01-01

To promote comprehensive utilization of mine waste tailings and control ground pressure, filling mine stopes with cement paste backfill (CPB) is becoming the most widely used and applicable method in contemporary underground mining. However, many urgent new problems have arisen during the exploitation in offshore mines owing to the complex geohydrology conditions. A series of rheological, settling and mechanical tests were carried out to study the influences of bittern ions on CPB properties in offshore mining. The results showed that: (1) the bittern ion compositions and concentrations of backfill water sampled in mine filling station were similar to seawater. Backfill water mixed CPB slurry with its higher viscosity coefficient was adverse to pipeline gravity transporting; (2) Bleeding rate of backfill water mixed slurry was lower than that prepared with tap water at each cement-tailings ratio; (3) The UCS values of backfill water mixed samples were higher at early curing ages (3d, 7d) and then became lower after longer curing time at 14d and 28d. Therefore, for mine production practice, the offshore environments can have adverse effects on the pipeline gravity transporting and have positive effects on stope dewatering process and early-age strength growth.

Evaluating Chagas disease progression and cure through blood-derived biomarkers: a systematic review.

PubMed

Requena-Méndez, Ana; López, Manuel Carlos; Angheben, Andrea; Izquierdo, Luis; Ribeiro, Isabela; Pinazo, Maria-Jesús; Gascon, Joaquim; Muñoz, José

2013-09-01

This article reviews the usefulness of various types of blood-derived biomarkers that are currently being studied to predict the progression of Chagas disease in patients with the indeterminate form, to assess the efficacy of antiparasitic drugs and to identify early cardiac and gastrointestinal damage. The authors used a search strategy based on MEDLINE, Cochrane Library Register for systematic review, EmBase, Global Health and LILACS databases. Out of 1716 screened articles, only 166 articles were eligible for final inclusion. The authors classified the biomarkers according to their biochemical structure and primary biological activity in four groups: i) markers of inflammation and cellular injury, ii) metabolic biomakers, iii) prothrombotic biomarkers and iv) markers derived from specific antigens of the parasite. Several potential biomarkers might have clinical potential for the detection of early cardiopathy. Such capacity is imperative in order to detect high-risk patients who require intensive monitoring and earlier therapy. Prospective studies with longer follow-ups are needed for the appraisal of biomarkers assessing clinical or microbiological cure after therapy. At the same time, studies evaluating more than one biomarker are useful to compare the efficacy among them given the lack of a recognized gold standard.

High-Performance Polymers Having Low Melt Viscosities

NASA Technical Reports Server (NTRS)

Jensen, Brian J.

2005-01-01

High-performance polymers that have improved processing characteristics, and a method of making them, have been invented. One of the improved characteristics is low (relative to corresponding prior polymers) melt viscosities at given temperatures. This characteristic makes it possible to utilize such processes as resin-transfer molding and resin-film infusion and to perform autoclave processing at lower temperatures and/or pressures. Another improved characteristic is larger processing windows that is, longer times at low viscosities. Other improved characteristics include increased solubility of uncured polymer precursors that contain reactive groups, greater densities of cross-links in cured polymers, improved mechanical properties of the cured polymers, and greater resistance of the cured polymers to chemical attack. The invention is particularly applicable to poly(arylene ether)s [PAEs] and polyimides [PIs] that are useful as adhesives, matrices of composite materials, moldings, films, and coatings. PAEs and PIs synthesized according to the invention comprise mixtures of branched, linear, and star-shaped molecules. The monomers of these polymers can be capped with either reactive end groups to obtain thermosets or nonreactive end groups to obtain thermoplastics. The synthesis of a polymeric mixture according to the invention involves the use of a small amount of a trifunctional monomer. In the case of a PAE, the trifunctional monomer is a trihydroxy- containing compound for example, 1,3,5-trihydroxybenzene (THB). In the case of a PI, the trifunctional monomer is a triamine for example, triamino pyrimidine or melamine. In addition to the aforementioned trifunctional monomer, one uses the difunctional monomers of the conventional formulation of the polymer in question (see figure). In cases of nonreactive end caps, the polymeric mixtures of the invention have melt viscosities and melting temperatures lower than those of the corresponding linear polymers of equal molecular weights. The lower melting temperatures and melt viscosities provide larger processing windows. In cases of reactive end caps, the polymeric mixtures of the invention have lower melt viscosities before curing and the higher cross-link densities after curing (where branching in the uncured systems would become cross-links in the cured systems), relative to the corresponding linear polymers of equal molecular weights. The greater cross-link densities afford increased resistance to chemical attack and improved mechanical properties.

Influence of curing time, overlay material and thickness on three light-curing composites used for luting indirect composite restorations.

PubMed

D'Arcangelo, Camillo; De Angelis, Francesco; Vadini, Mirco; Carluccio, Fabio; Vitalone, Laura Merla; D'Amario, Maurizio

2012-08-01

To assess the microhardness of three resin composites employed in the adhesive luting of indirect composite restorations and examine the influence of the overlay material and thickness as well as the curing time on polymerization rate. Three commercially available resin composites were selected: Enamel Plus HRI (Micerium) (ENA), Saremco ELS (Saremco Dental) (SAR), Esthet-X HD (Dentsply/DeTrey) (EST-X). Post-polymerized cylinders of 6 different thicknesses were produced and used as overlays: 2 mm, 3 mm, 3.5 mm, 4 mm, 5 mm, and 6 mm. Two-mm-thick disks were produced and employed as underlays. A standardized amount of composite paste was placed between the underlay and the overlay surfaces which were maintained at a fixed distance of 0.5 mm. Light curing of the luting composite layer was performed through the overlays for 40, 80, or 120 s. For each specimen, the composite to be cured, the cured overlay, and the underlay were made out of the same batch of resin composite. All specimens were assigned to three experimental groups on the basis of the resin composite used, and to subgroups on the basis of the overlay thickness and the curing time, resulting in 54 experimental subgroups (n = 5). Forty-five additional specimens, 15 for each material under investigation, were produced and subjected to 40, 80, or 120 s of light curing using a microscope glass as an overlay; they were assigned to 9 control subgroups (n = 5). Three Vicker's hardness (VH) indentations were performed on each specimen. Means and standard deviations were calculated. Data were statistically analyzed using 3-way ANOVA. Within the same material, VH values lower than 55% of control were not considered acceptable. The used material, the overlay thickness, and the curing time significantly influenced VH values. In the ENA group, acceptable hardness values were achieved with 3.5-mm or thinner overlays after 120 or 80 s curing time (VH 41.75 and 39.32, respectively), and with 2-mm overlays after 40 s (VH 54.13). In the SAR group, acceptable hardness values were only achieved with 2-mm-thick overlays after 120 or 80 s curing time (VH 39.81 and 29.78, respectively). In the EST-X group, acceptable hardness values were only achieved with 3-mm or thinner overlays, after 120 or 80 s curing time (VH 36.20 and 36.03, respectively). Curing time, restoration thickness, and overlay material significantly influenced the microhardness of the tested resin composites employed as luting agents. The clinician should carefully keep these factors under control.

Effect of CNT addition on cure kinetics of glass fiber/epoxy composite

NASA Astrophysics Data System (ADS)

Fulmali, A. O.; Kattaguri, R.; Mahato, K. K.; Prusty, R. K.; Ray, B. C.

2018-03-01

In present time, developments in reinforced polymer composites have acquired preferential attention for high performance and high precision applications like aerospace, marine and transportation. Fibre reinforced polymer (FRP) composites are being substituted because of their low density, higher strength, stiffness, impact resistance, and improved corrosion resistance. Further laminated composites exhibit superior in-plane mechanical properties that are mostly governed by the fibers. However, laminated FRP composites suffer from poor out of plane properties in some applications. These properties can further be improved by the addition of Nano fillers like carbon nanotube (CNT), graphene and so on. Curing cycle plays a very important role in drawing out the optimum property of glass fiber/epoxy (GE) composite. It is expected that the cure kinetics can further be altered by addition of CNT due to its higher aspect ratio. The main objective of this work is to study the effect of CNT addition on cure kinetics of GE composite as multi-segment adsorption of polymer takes place on the CNT surface. In this study effects of curing parameters on mechanical properties and glass transition temperature of CNT embedded glass fiber/epoxy composite (CNT-GE) has been evaluated. For this study control GE and CNT-GE (with 0.1 wt. %) laminates were fabricated using hand lay-up technique followed by hot compression. The curing parameters that were considered in the present investigation were temperature (80°C, 110°C, and 140°C) and time (0.5 hr, 3 hr and 6 hr). For different combination of above mentioned temperature and time, samples of GE and CNT-GE composites were post cured. Mechanical properties were determined by flexural testing using 3 point bending fixture on INSTRON-5967 and thermal properties i.e. glass transition temperature (Tg) determined by Differential Scanning Calorimeter (DSC) to evaluate the effects of curing parameters. For CNT-GE samples, No much variation observed in flexural modulus with increase in post curing temperature and time, but swift increment was observed in flexural strength at 140°C with increase in post cure time. Elevation in Tg observed with increase in temperature and time duration of post curing; highest Tg noted at 140°C-6hr. Optimum post curing parameters for CNT-GE composite observed to be 140°C-6hr.

Use of sodium dodecyl sulfate pretreatment and 2-stage curing for improved quality of salted duck eggs.

PubMed

Lian, Zixuan; Qiao, Longshan; Zhu, Guanghong; Deng, Yun; Qian, Bingjun; Yue, Jin; Zhao, Yanyun

2014-03-01

The effects of use of sodium dodecyl sulfate (SDS) pretreatment and 2-stage curing on the microbial, physicochemical, and microstructural qualities of salted duck eggs were studied. After pretreatment in 0.5% (w/v) SDS solution at room conditions for 15 min, no discolorations were observed and no microorganisms were detected on the egg shells. In the 2-stage curing process, 25% (w/v) and 30% (w/v) saline solutions were evaluated in the 1st step (Stage I, approximately 18 d), whereas 4% (w/v) saline solution was applied in the 2nd step (Stage II, approximately 15 d). Along with increased curing time, water content decreased and NaCl content increased in the egg yolks from approximately 0.40% to 0.86%, whereas the water content of egg albumen remained at approximately 85% during the 2-stage curing. More importantly, the NaCl content of albumen maintained at approximately 4.0% at Stage II curing. Yolk index as a sign of maturity for salted duck eggs reached 1 at the end of Stage I (18 d) and retained the same value during Stage II curing regardless of the NaCl concentration in the Stage I saline solution. Oil exudation in egg yolks increased as the time of curing increased. As seen from scanning electron microscopy, oil was released from yolk granules. This study indicated that SDS pretreatment is effective to reduce microbial load on the shells of fresh duck eggs and the 2-stage curing can improve physicochemical qualities of the salted duck eggs and shortened curing time to about 7 to 17 d as compared to the traditional 1-step curing method. Spoiled saline solution and uneven distribution of salt are the 2 major problems in producing salted duck eggs. Sodium dodecyl sulfate (SDS) pretreatment and 2-stage curing process have shown effective to solve these problems, respectively. The SDS pretreatment was able to remove microorganisms and soil from the surface of fresh egg shells, thus preventing the spoilage of the saline solution. The 2-stage curing process successfully controlled the NaCl content of egg albumen and yolk in the final product, and shortened the curing time compared to the traditional 1-step curing method. © 2014 Institute of Food Technologists®

Medical treatment of primary biliary cirrhosis and primary sclerosing cholangitis.

PubMed

Holtmeier, J; Leuschner, U

2001-01-01

Treatment of primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC) with ursodeoxycholic acid (UDCA) has been in common use since 1985. In PBC, treatment with UDCA improves laboratory data, liver histology, enables a longer transplantation-free interval and prolongs disease survival. Because UDCA is unable to cure the disease newer drugs or combination therapies are still needed. Studies with UDCA and immunosuppressants such as prednisone, budesonide and azathioprine have shown that in selected patients combination therapy may be superior to UDCA monotherapy. PSC is treated successfully with UDCA and endoscopic dilatation of the bile duct strictures. Treatment of extrahepatic manifestations of cholestatic liver disease such as pruritus, fatigue, osteoporosis and steatorrhea can be problematic and time-consuming. Copyright 2001 S. Karger AG, Basel

An investigation of the curing process for moisture-crosslinkable polyethylene used in cable coating extrusion

NASA Astrophysics Data System (ADS)

Cantor, Kirk Martin

1998-12-01

Moisture-crosslinkable polyethylene used in the extrusion coating of electrical cable has many advantages over other polymer systems used for crosslinked cable coating. However, one of its major drawbacks is the long cure times required. The purpose of this study was to describe how curing takes place in cable systems using moisture-crosslinkable polyethylene, with an ultimate goal of gaining insight into how cure times might be reduced. Crosslinking was investigated with an emphasis on how the curing reaction proceeds through the coating, using analyses to characterize processing conditions and resulting mechanical and structural properties. In the design of the study, material compounds were varied as were curing conditions. Cable coatings were sectioned by position through the coating thickness and characterized using several techniques. Mechanical, thermal, and structural properties of the polymer coating were measured. A significant finding from the study was that the degree of cure was highest at positions in the coating closest to the conductor. Because this was opposite to what was expected, an investigation into the cause of this finding was pursued. It was found that during cure at elevated temperature, the inside surface of the coating remains at a generally higher temperature than the outside surface. This provides a more favorable cure condition for positions in the coating closest to the conductor. Based on the results of this study, a list of suggested follow-up studies is provided at the end of the dissertation. One proposal for investigating reduced cure times involves providing heat to the interior of the cable during cure.

Accelerated dry curing of hams.

PubMed

Marriott, N G; Kelly, R F; Shaffer, C K; Graham, P P; Boling, J W

1985-01-01

Uncured pork legs from the right side of 18 carcasses were treated with a Ross Tenderizer and the left side were controls. All 36 samples were dry-cured for 40, 56 or 70 days and evaluated for appearance traits, cure penetration characteristics, microbial load, Kramer Shear force and taste attributes. The tenderization treatment had no effect (P > 0·05) on visual color or cure penetration rate, weight loss before curing, percentage moisture, nitrate level, nitrite level, total plate count, anaerobic counts, psychrotrophic counts, objective and subjective tenderness measurements or juiciness. However, the higher values of salt suggested a possible acceleration of the dry cure penetration process among the tenderized samples. Cure time had no effect (P > 0·05) on percentage moisture, percentage salt, nitrate content, nitrite content, shear force and juiciness. Results suggest a limited effect of the mechanical tenderization process on certain traits related to dry curing and that total process time should be at least 70 days if color stability during cooking is desired. Copyright © 1985. Published by Elsevier Ltd.

Evaluation of microleakage of class II dental composite resin restorations cured with LED or QTH dental curing light; Blind, Cluster Randomized, In vitro cross sectional study

PubMed Central

2014-01-01

Background The aim of this study is to compare the microleakage of Class II dental composite resin restorations which have been cured by three different LED (light emitting diode) light curing modes compared to control samples cured by QTH (quartz tungsten halogen) light curing units (LCUs), to determine the most effective light curing unit and mode of curing. Results In this experimental study, class II cavities were prepared on 100 sound human premolars which have been extracted for orthodontic treatment. The teeth were randomly divided into four groups; three experimental and one control group of 25 teeth each. Experimental groups were cured by either conventional, pulse-delay, or ramped curing modes of LED. The control group was cured for 20 seconds by QTH. The restorations were thermocycled (1000 times, between 5 and 55°C, for 5 seconds dwell time), dyed, sectioned mesio-distally and viewed under stereo-microscope (40×) magnification. Teeth were then scored on a 0 to 4 scale based on the amount of microleakage. The data were analyzed by Chi-square test. No significant difference was demonstrated between the different LCUs (light curing units), or modes of curing, at the enamel side (p > 0.05). At the dentin side, all modes of LED curing could significantly reduce microleakage (p < 0.05). The results suggest that slow start curing improves marginal integrity and seal. High intense curing endangers those aims. Conclusions Comparison between the three LED mode cured composite resin restorations and QTH curing showed LED curing in all modes is more effective than QTH for reducing microleakage. Both LED and QTH almost completely eliminate the microleakage on the enamel side, however none of them absolutely eliminated microleakage on the dentin side. PMID:24990296

Cure rate model with interval censored data.

PubMed

Kim, Yang-Jin; Jhun, Myoungshic

2008-01-15

In cancer trials, a significant fraction of patients can be cured, that is, the disease is completely eliminated, so that it never recurs. In general, treatments are developed to both increase the patients' chances of being cured and prolong the survival time among non-cured patients. A cure rate model represents a combination of cure fraction and survival model, and can be applied to many clinical studies over several types of cancer. In this article, the cure rate model is considered in the interval censored data composed of two time points, which include the event time of interest. Interval censored data commonly occur in the studies of diseases that often progress without symptoms, requiring clinical evaluation for detection (Encyclopedia of Biostatistics. Wiley: New York, 1998; 2090-2095). In our study, an approximate likelihood approach suggested by Goetghebeur and Ryan (Biometrics 2000; 56:1139-1144) is used to derive the likelihood in interval censored data. In addition, a frailty model is introduced to characterize the association between the cure fraction and survival model. In particular, the positive association between the cure fraction and the survival time is incorporated by imposing a common normal frailty effect. The EM algorithm is used to estimate parameters and a multiple imputation based on the profile likelihood is adopted for variance estimation. The approach is applied to the smoking cessation study in which the event of interest is a smoking relapse and several covariates including an intensive care treatment are evaluated to be effective for both the occurrence of relapse and the non-smoking duration. Copyright (c) 2007 John Wiley & Sons, Ltd.

The syndrome of `continuous muscle-fibre activity' cured: further studies

PubMed Central

Isaacs, Hyam; Heffron, J. J. A.

1974-01-01

Two cases suffering from the syndrome of `continuous muscle-fibre activity' have been followed-up for 14 years. These patients have gradually gone into remission and no longer require therapy. The results of recent histology, histochemistry, and electronmicroscopy, as well as sural nerve biopsy studies, are presented. The sarcoplasmic reticulum calcium binding activity and ATPase activity are normal. Images PMID:4281819

Unusual cause of chronic cough in a four-year-old cured by uvulectomy.

PubMed

Najada, Abdelhamid; Weinberger, Miles

2002-08-01

A 4-year-old boy had a history of persistent barking cough unresponsive to medical treatment since infancy. He described a feeling of something in his throat. When investigated by flexible fiberoptic bronchoscopy, the only abnormality was the uvula resting in contact with the epiglottis. The cough was no longer present after uvulectomy. Copyright 2002 Wiley-Liss, Inc.

7 CFR 1463.106 - Base quota levels for eligible tobacco producers.

Code of Federal Regulations, 2012 CFR

2012-01-01

...)—.952381 (iv) Virginia Sun-cured (type 37) 1.0000 3 Multiply the sum from Step 2 times the farm's average... (35-36)—.952381 (iv) Virginia Sun-cured (type 37) 1.0000 6 Multiply the sum from Step 5 times the farm... (35-36)—.94264 (iv) Virginia Sun-cured (type 37) 1.0000 3 Multiply the sum from Step 2 times the farm...

7 CFR 1463.106 - Base quota levels for eligible tobacco producers.

Code of Federal Regulations, 2013 CFR

2013-01-01

...)—.952381 (iv) Virginia Sun-cured (type 37) 1.0000 3 Multiply the sum from Step 2 times the farm's average... (35-36)—.952381 (iv) Virginia Sun-cured (type 37) 1.0000 6 Multiply the sum from Step 5 times the farm... (35-36)—.94264 (iv) Virginia Sun-cured (type 37) 1.0000 3 Multiply the sum from Step 2 times the farm...

7 CFR 1463.106 - Base quota levels for eligible tobacco producers.

Code of Federal Regulations, 2014 CFR

2014-01-01

...)—.952381 (iv) Virginia Sun-cured (type 37) 1.0000 3 Multiply the sum from Step 2 times the farm's average... (35-36)—.952381 (iv) Virginia Sun-cured (type 37) 1.0000 6 Multiply the sum from Step 5 times the farm... (35-36)—.94264 (iv) Virginia Sun-cured (type 37) 1.0000 3 Multiply the sum from Step 2 times the farm...

7 CFR 1463.106 - Base quota levels for eligible tobacco producers.

Code of Federal Regulations, 2011 CFR

2011-01-01

...)—.952381 (iv) Virginia Sun-cured (type 37) 1.0000 3 Multiply the sum from Step 2 times the farm's average... (35-36)—.952381 (iv) Virginia Sun-cured (type 37) 1.0000 6 Multiply the sum from Step 5 times the farm... (35-36)—.94264 (iv) Virginia Sun-cured (type 37) 1.0000 3 Multiply the sum from Step 2 times the farm...

Light curing through glass ceramics: effect of curing mode on micromechanical properties of dual-curing resin cements.

PubMed

Flury, Simon; Lussi, Adrian; Hickel, Reinhard; Ilie, Nicoleta

2014-04-01

The aim of this study was to investigate micromechanical properties of five dual-curing resin cements after different curing modes including light curing through glass ceramic materials. Vickers hardness (VH) and indentation modulus (Y HU) of Panavia F2.0, RelyX Unicem 2 Automix, SpeedCEM, BisCem, and BeautiCem SA were measured after 1 week of storage (37 °C, 100 % humidity). The resin cements were tested following self-curing or light curing with the second-generation light-emitting diode (LED) curing unit Elipar FreeLight 2 in Standard Mode (1,545 mW/cm(2)) or with the third-generation LED curing unit VALO in High Power Mode (1,869 mW/cm(2)) or in XtraPower Mode (3,505 mW/cm(2)). Light curing was performed directly or through glass ceramic discs of 1.5 or 3 mm thickness of IPS Empress CAD or IPS e.max CAD. VH and Y HU were analysed with Kruskal-Wallis tests followed by pairwise Wilcoxon rank sum tests (α = 0.05). RelyX Unicem 2 Automix resulted in the highest VH and Y HU followed by BeautiCem SA, BisCem, SpeedCEM, and finally Panavia F2.0. Self-curing of RelyX Unicem 2 Automix and SpeedCEM lowered VH and Y HU compared to light curing whereas self-curing of Panavia F2.0, BisCem, and BeautiCem SA led to similar or significantly higher VH and Y HU compared to light curing. Generally, direct light curing resulted in similar or lower VH and Y HU compared to light curing through 1.5-mm-thick ceramic discs. Light curing through 3-mm-thick discs of IPS e.max CAD generally reduced VH and Y HU for all resin cements except SpeedCEM, which was the least affected by light curing through ceramic discs. The resin cements responded heterogeneously to changes in curing mode. The applied irradiances and light curing times adequately cured the resin cements even through 1.5-mm-thick ceramic discs. When light curing resin cements through thick glass ceramic restorations, clinicians should consider to prolong the light curing times even with LED curing units providing high irradiances.

Insufficient cure under the condition of high irradiance and short irradiation time.

PubMed

Feng, Li; Carvalho, Ricardo; Suh, Byoung I

2009-03-01

To investigate if and why a plasma arc curing (PAC) light tends to undercure methacrylate-based resins or resin composites. Model dimethacrylate resins, commercial dental adhesives, and commercial resin composites were cured using a PAC light and a halogen light with the similar radiant exposures but different combinations of irradiance and irradiation time. The degree of double bond conversion (DC) was measured with FTIR spectroscopy and analyzed as a function of radiant exposure. The PAC light produced a lower DC than the halogen light for the model resin with the lowest viscosity and for three of the four adhesives. With a high irradiance, the PAC light could cure three of the four composites as thoroughly as its halogen counterpart. When the irradiance was reduced, however, three composites yielded a lower DC. Insufficient cure by PAC lights or any curing lights with very high irradiance is likely to happen when too short an irradiation time is used. It is because under higher irradiance, the lifetime of free radicals is shorter.

Polyprenyl Immunostimulant Treatment of Cats with Presumptive Non-Effusive Feline Infectious Peritonitis In a Field Study

PubMed Central

Legendre, Alfred M.; Kuritz, Tanya; Galyon, Gina; Baylor, Vivian M.; Heidel, Robert Eric

2017-01-01

Feline infectious peritonitis (FIP) is a fatal disease with no clinically effective treatment. This field study evaluated treatment with Polyprenyl Immunostimulant (PI) in cats with the non-effusive form of FIP. Because immune suppression is a major component in the pathology of FIP, we hypothesized that treatment with an immune system stimulant would increase survival times of cats with dry FIP. Sixty cats, diagnosed with dry FIP by primary care and specialist veterinarians and meeting the acceptance criteria, were treated with PI without intentional selection of less severe cases. The survival time from the start of PI treatment in cats diagnosed with dry FIP showed that of the 60 cats with dry FIP treated with PI, 8 survived over 200 days, and 4 of 60 survived over 300 days. A literature search identified 59 cats with non-effusive or dry FIP; no cat with only dry FIP lived longer than 200 days. Veterinarians of cats treated with PI that survived over 30 days reported improvements in clinical signs and behavior. The survival times in our study were significantly longer in cats who were not treated with corticosteroids concurrently with PI. While not a cure, PI shows promise in the treatment of dry form FIP, but a controlled study will be needed to verify the benefit. PMID:28261584

Development of processing diagrams for polymeric die attach adhesives

NASA Astrophysics Data System (ADS)

Hsiung, Jen-Chou

With a processing diagram, one can reduce the effort required to customize curing process conditions for polymeric die attach adhesives. Polymeric die attach adhesives are often cured per the manufacturer's recommendations during initial screening evaluations. In most cases, the recommended cure schedules have to be modified so as to fit differences in process equipment. Unfortunately, the modified cure schedule is usually determined by a trial-and-error method. An aim of our experiments is to understand the curing process of a wide range of polymeric die attach adhesives (conventional, fast, and snap cure adhesives) and to construct a processing diagram, i.e., "Bondability Diagram", so as to define the processing window. Such diagrams should be helpful in determining both the time and cure temperature required to produce high quality bonds. The bondability diagram can be constructed based on fundamental understandings of the phenomena involved in the curing process using a wide variety of tools. Differential Scanning Calorimetry (DSC) is utilized to study the cure kinetics and the extent of reaction. Dynamic Mechanical Analysis (DMA) is used to determine gelation times and melt viscosity under a shear mode. A modified Rheovibron is employed to perform cure characterizations under a tensile mode so that cure stresses could be determined. Thermogravimetric Analysis (TGA) is used to evaluate the outgassing phenomena. Optical Microscopy (OM) is used to detect voids. Results indicate that the cure behaviors of conventional, fast, and snap cure adhesives are different in several respects. The combination of DSC, DMA, TGA, OM, and lap shear test leads to a frame work of developing the bondability diagram concept. The bondability diagram concept provides a foundation for an understanding of the recommended cure schedule and allows one to design their own cure schedule.

New curing system for urea-formaldehyde resins with polyhydrazides. I. Curing with poly(methycrylol hydrazide)

Treesearch

Katsumasa Miyake; Bunichiro Tomita; Chung-Yun Hse; George E. Myers

1989-01-01

A new curing system for urea-formaldehyde (UF) resins was investigated using poly(methacryloyl hydrazide) as the curing reagent. Results were as follows: 1) Gel time and the water-soluble part of cured resins were determined as function of pH and molar ratio [hydrazide group/(free formaldehyde+methylol group)]. It was found that the reaction in this system proceeds for...

Superior long-term outcome with idarubicin compared with high-dose daunorubicin in patients with acute myeloid leukemia age 50 years and older.

PubMed

Gardin, Claude; Chevret, Sylvie; Pautas, Cécile; Turlure, Pascal; Raffoux, Emmanuel; Thomas, Xavier; Quesnel, Bruno; de Revel, Thierry; de Botton, Stéphane; Gachard, Nathalie; Renneville, Aline; Boissel, Nicolas; Preudhomme, Claude; Terré, Christine; Fenaux, Pierre; Bordessoule, Dominique; Celli-Lebras, Karine; Castaigne, Sylvie; Dombret, Hervé

2013-01-20

Although standard chemotherapy remains associated with a poor outcome in older patients with acute myeloid leukemia (AML), it is unclear which patients can survive long enough to be considered as cured. This study aimed to identify factors influencing the long-term outcome in these patients. The study included 727 older patients with AML (median age, 67 years) treated in two idarubicin (IDA) versus daunorubicin (DNR) Acute Leukemia French Association trials. Prognostic analysis was based on standard univariate and multivariate models and also included a cure fraction model to focus on long-term outcome. Age, WBC count, secondary AML, Eastern Cooperative Oncology Group (ECOG) performance status (PS), and adverse-risk and favorable-risk AML subsets (European LeukemiaNet classification) all influenced complete remission (CR) rate and overall survival (OS). IDA random assignment was associated with higher CR rate, but not with longer OS (P = .13). The overall cure rate was 13.3%. Older age and ECOG-PS more than 1 negatively influenced cure rate, which was higher in patients with favorable-risk AML (39.1% v 8.0% in adverse-risk AML; P < .001) and those treated with IDA (16.6% v 9.8% with DNR; P = .018). The long-term impact of IDA was still observed in patients younger than age 65 years, although all of the younger patients in the DNR control arm received high DNR doses (cure rate, 27.4% for IDA v 15.9% for DNR; P = .049). In multivariate analysis, IDA random assignment remained associated with a higher cure rate (P = .04), together with younger age and favorable-risk AML, despite not influencing OS (P = .11). In older patients with AML, younger age, favorable-risk AML, and IDA treatment predict a better long-term outcome.

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.

Use of near-IR to monitor the influence of external heating on dental composite photopolymerization.

PubMed

Trujillo, Marianela; Newman, Sheldon M; Stansbury, Jeffrey W

2004-10-01

This study was conducted to determine the effect of modest external heating on the photopolymerization kinetics and conversion of commercial dental composite restorative materials. A transmission-mode, real-time near-infrared spectroscopic technique was used to monitor the photopolymerization process in the composite materials at various temperatures between 23 and 70 degrees C. Several light curing units, differing in spectral output and power densities were compared at the different cure temperatures. Several significantly different commercial composites were compared for their response. Regardless of the curing light or composite material used, photopolymerization at a moderate curing temperature of 54.5 degrees C resulted in significantly higher immediate and final conversion values compared with room temperature photocuring. Contrary to the room temperature cured materials, at the elevated cure temperature the extent of post-cure was minor and different curing lights produced very uniform conversion values within a given material. The time required to reach a given level of conversion, established as full conversion with the room temperature cure, was reduced typically by 80-90% using the elevated curing conditions. Complementary kinetic studies confirmed the effect of cure temperature on increasing the polymerization rate in dental composites as significant. Increasing the temperature of composite resin within potentially biologically compatible limits can significantly influences resin polymerization. These increased rates and conversion could lead to improved properties of composite restorative materials.

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.

Measurement of the degree of cure in epoxies with ultrasonic velocity

NASA Technical Reports Server (NTRS)

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

1986-01-01

The use of ultrasonic longitudinal velocity values to measure the degree of cure (defined for an epoxide system as the concentration of epoxide/amine bonds divided by the initial epoxide concentration) in epoxy resins is investigated. The experimental setup used to measure the changes in longitudinal velocity with time is described, together with the technique used to calculate the degree of cure from the acoustic data, using the principle of additive module. Measurements were done with diglycidyl ether of bisphenol A epoxy resin cured with an amine adduct agent. Good qualitative agreement was shown between the time dependence of the acoustically measured degree of cure and the predicted rate of reaction.

Assessment of curing behavior of light-activated dental composites using intensity correlation based multiple reference optical coherence tomography.

PubMed

Dsouza, Roshan; Subhash, Hrebesh; Neuhaus, Kai; Kantamneni, Ramakrishna; McNamara, Paul M; Hogan, Josh; Wilson, Carol; Leahy, Martin

2016-01-01

Monitoring the curing kinetics of light-activated resin is a key area of research. These resins are used in restorative applications and particularly in dental applications. They can undergo volumetric shrinkage due to poor control of the depth dependent curing process, modulated by the intensity and duration of the curing light source. This often results in the formation of marginal gaps, causing pain and damage to the restoration site. In this study, we demonstrate the capabilities of a correlation method applied using a multiple references optical coherence tomography (MR-OCT) architecture to monitor the curing of the resin. A MR-OCT system is used in this study to monitor the curing of the resin. The system operates at the center wavelength of 1310 nm with an A-scan rate of 1200 A-scans per second. The axial and lateral resolution of the system is ∼13 μm and ∼27 μm. The method to determine the intensity correlation between adjacent B-frames is based on the Pearson correlation coefficient for a region of interest. Calculating the correlation coefficient for multiple B-frames related to the first B-frame at regular spaced time points, shows for a noncured resin a reduction of the correlation coefficient over time due to Brownian motion. The time constant of the reduction of the correlation value is a measure for the progress of the polymerization during LED light irradiation of the resin. The proposed approach is potentially a low-cost, powerful and unique optical imaging modality for measuring the curing behavior of dental resin and other resins, coatings, and adhesives in medical and industrial applications. To demonstrate the proposed method to monitor the curing process, a light-activated resin composite from GRADIA DIRECT ANTERIOR (GC Corporation, Japan) is studied. The curing time of resin was measured and monitored as a function of depth. The correlation coefficient method is highly sensitive to Brownian motion. The process of curing results in a change in intensity as measured by the MR-OCT signal and hence can be monitored using this method. These results show that MR-OCT has the potential to measure the curing time and monitor the curing process as a function of depth. Moreover, MR-OCT as a product has potential to be compact, low-cost and to fit into a smartphone. Using such a device for monitoring the curing of the resin will be suitable for dentists in stationary and mobile clinical settings. © 2015 Wiley Periodicals, Inc.

Population-based survival-cure analysis of ER-negative breast cancer.

PubMed

Huang, Lan; Johnson, Karen A; Mariotto, Angela B; Dignam, James J; Feuer, Eric J

2010-08-01

This study investigated the trends over time in age and stage specific population-based survival of estrogen receptor negative (ER-) breast cancer patients by examining the fraction of cured patients and the median survival time for uncured patients. Cause-specific survival data from the Surveillance, Epidemiology, and End Results program for cases diagnosed during 1992-1998 were used in mixed survival cure models to evaluate the cure fraction and the extension in survival for uncured patients. Survival trends were compared with adjuvant chemotherapy data available from an overlapping patterns-of-care study. For stage II N+ disease, the largest increase in cure fraction was 44-60% (P = 0.0257) for women aged >or=70 in contrast to a 7-8% point increase for women aged <50 or 50-69 (P = 0.056 and 0.038, respectively). For women with stage III disease, the increases in the cure fraction were not statistically significant, although women aged 50-69 had a 10% point increase (P = 0.103). Increases in cure fraction correspond with increases in the use of adjuvant chemotherapy, particularly for the oldest age group. In this article, for the first time, we estimate the cure fraction for ER- patients. We notice that at age >o5r=70, the accelerated increase in cure fraction from 1992 to 1998 for women with stage II N+ compared with stage III suggests a selective benefit for chemotherapy in the lower stage group.

[Study on clinical effectiveness of acupuncture and moxibustion on acute Bell's facial paralysis: randomized controlled clinical observation].

PubMed

Wu, Bin; Li, Ning; Liu, Yi; Huang, Chang-qiong; Zhang, Yong-ling

2006-03-01

To investigate the adverse effects of acupuncture on the prognosis, and effectiveness of acupuncture combined with far infrared ray in the patient of acute Bell's facial paralysis within 48 h. Clinically randomized controlled trial was used, and the patients were divided into 3 groups: group A (early acupuncture group), group B (acupuncture combined with far infrared ray) and group C (acupuncture after 7 days). The facial nerve functional classification at the attack, 7 days after the attack and after treatment, the clinically cured rate of following-up of 6 months, and the average cured time, the cured time of complete facial paralysis were observed in the 3 groups. There were no significant differences among the 3 groups in the facial nerve functional classification 7 days after the attack, the clinically cured rate of following-up of 6 months and the average cured time (P > 0.05), but the cured time of complete facial paralysis in the group A and the group B were shorter than that in the group C (P < 0.05). The patient of acute Bell's facial paralysis can be treated with acupuncture and moxibustion, and traditional moxibustion can be replaced by far infrared way.

Influence of light-curing sources on polymerization reaction kinetics of a restorative system.

PubMed

D'Alpino, Paulo H P; Svizero, Nádia R; Pereira, José C; Rueggeberg, Frederick A; Carvalho, Ricardo M; Pashley, David H

2007-02-01

To determine the effect of using a variety of commercial light-curing units on polymerization of a dentin-bonding agent (Adper Single Bond) and of a resin composite (Filtek Z250). Infrared (IR) spectra were obtained kinetically at one scan/second at 2 cm(-1) resolution for a period of 5 minutes and were analyzed for: maximum conversion rate (%/s), time into exposure when maximum rate occurred (seconds), conversion at maximum rate (%), and total conversion (%) at 300 seconds by comparison of aliphatic-to-aromatic absorption IR peak ratios, before and after polymerization. Light units used were: QTH 540 mW/cm2 (XL3000); LED 750 mW/cm2 (Elipar FreeLight 2); PAC 2,130 mW/cm2 (ARC II). Exposure followed manufacturers' recommendations: dentin bonding agent for 10 seconds, RC for 20 seconds (QTH), and 10 seconds (LED and PAC). Polymerization kinetics was evaluated at the bottom surface (2.5 mm thick) for the resin composite and as a thin film for the dentin bonding agent on the diamond surface of an attenuated total reflectance accessory in the IR spectrometer. Values (n = 5) were compared using ANOVA and Tukey's pairwise post-hoc test: pre-set alpha 0.05. PAC produced the highest total conversion and conversion rate for the resin composite (P < 0.05). Total conversion was lower for dentin bonding adhesive using PAC than with LED or QTH (P < 0.05). LED provided the highest proportion of conversion at the maximum rate with respect to conversion at 300 seconds for both materials. QTH demonstrated the lowest maximum rate value that occurred at a longer time into exposure (P < 0.05). Polymerization kinetic parameters varied greatly between the restorative materials as well as among light-curing unit types when compared to values observed when using a QTH light as control.

Reversing Glass Wettability

NASA Technical Reports Server (NTRS)

Frazier, D. O.; Smith, J. E., Jr.; Kaukler, W. F.

1985-01-01

Treatment reverses wettability of glassware: Liquids that normally wet glass no longer do, and those that do not wet glass are made to do so. Useful in research on container effects in nucleation and growth of secondary phase from solution. Treatment consists of spreading 3 percent (by weight) solution of silicone oil in hexane isomers over glass, drying in air, and curing at 300 degrees C in vacuum for one hour.

Effect of carbon black composition with sludge palm oil on the curing characteristic and mechanical properties of natural rubber/styrene butadiene rubber compound

NASA Astrophysics Data System (ADS)

Mohamed, R.; Nurazzi, N. Mohd; Huzaifah, M.

2017-07-01

This study was conducted to investigate the possibility of utilizing sludge palm oil (SPO) as processing oil, with various amount of carbon black as its reinforcing filler, and its effects on the curing characteristics and mechanical properties of natural rubber/styrene butadiene rubber (NR/SBR) compound. Rubber compound with fixed 15 pphr of SPO loading, and different carbon black loading from 20 to 50 pphr, was prepared using two roll mills. The cure characteristics and mechanical tests that have been conducted are the scorch and cure time analysis, tensile strength and tear strength. Scorch time (ts5) and cure time (t90) of the compound increases with the increasing carbon black loading. The mechanical properties of NR/SBR compound viz. the tensile strength, modulus at 300% strain and tear strength were also improved by the increasing carbon black loading.

Time scales of radiation damage decay in four optical materials

NASA Astrophysics Data System (ADS)

Grupp, Frank; Geis, Norbert; Katterloher, Reinhard; Bender, Ralf

2017-09-01

In the framework of the qualification campaigns for the near infrared spectrometer and photometer instrument (NISP) on board the ESA/EUCLID satellite six optical materials where characterized with respect to their transmission losses after a radiation dose representing the mission exposure to high energy particles in the outer Lagrange point L2. Data was taken between 500 and 2000nm on six 25mm thick coated probes. Thickness and coating being representative for the NISP flight configuration. With this paper we present results owing up the radiation damage shown in [1]. We where able to follow up the decay of the radiation damage over almost one year under ambient conditions. This allows us to distinguish between curing effects that happen on different time-scales. As for some of the materials no radiation damage and thus no curing was detected, all materials that showed significant radiation damage in the measured passband showed two clearly distinguished time scales of curing. Up to 70% of the transmission losses cured on half decay time scales of several tens of days, while the rest of the damage cures on time scales of years.

Real-time Cure Monitoring of Composites Using a Guided wave-based System with High Temperature Piezoelectric Transducers, Fiber Bragg Gratings, and Phase-shifted Fiber Bragg Gratings

NASA Astrophysics Data System (ADS)

Hudson, Tyler Blake

An in-process, in-situ cure monitoring technique utilizing a guided wave-based concept for carbon fiber reinforced polymer (CFRP) composites was investigated. Two automated cure monitoring systems using guided-wave ultrasonics were developed for characterizing the state of the cure. In the first system, surface mounted high-temperature piezoelectric transducer arrays were employed for actuation and sensing. The second system motivated by the success of the first system includes a single piezoelectric disc, bonded onto the surface of the composite for excitation; fiber Bragg gratings (FBGs) and/or phase-shifted fiber Bragg gratings (PSFBGs) were embedded in the composite for distributed cure sensing. Composite material properties (viscosity and degree of cure) evolved during cure of the panels fabricated from HexcelRTM IM7/8552 prepreg correlated well to the amplitude, time of arrival, and group velocity of the guided wave-based measurements during the cure cycle. In addition, key phase transitions (gelation and vitrification) were clearly identified from the experimental data during the same cure cycle. The material properties and phase transitions were validated using cure process modeling software (e.g., RAVENRTM). The high-temperature piezoelectric transducer array system demonstrated the feasibility of a guided wave-based, in-process, cure monitoring and provided the framework for defect detection during cure. Ultimately, this system could provide a traceable data stream for non-compliance investigations during serial production and perform closed-loop process control to maximize composite panel quality and consistency. In addition, this system could be deployed as a "smart" caul/tool plate to existing production lines without changing the design of the aircraft/structure. With the second system, strain in low frequency (quasi-static) and the guided wavebased signals in several hundred kilohertz range were measured almost simultaneously using the same FBG or PS-FBG throughout the cure cycle. Also, the residual strain can be readily determined at the end of the cure. This system demonstrated a real-time, in-situ, cure monitoring system using embedded multiplexed FBG/PS-FBG sensors to record both guided wave-based signals and strain. The distinct advantages of a fiber optic-based system include multiplexing, small size, embedding, utilization in harsh environments, electrically passive operation, and electromagnetic interference (EMI) immunity. The embedded multiplexed FBG/PS-FBG fiber optic sensor can monitor the entire life-cycle of the composite structure from curing, post-cure/assembly, and in-service for creating "smart structures".

Dual and self-curing potential of self-adhesive resin cements as thin films.

PubMed

Moraes, R R; Boscato, N; Jardim, P S; Schneider, L F J

2011-01-01

In this study, the dual- and self-curing potential of self-adhesive resin cements (SARCs) as thin, clinically-relevant cement films was investigated. The SARCs tested were: BisCem (BSC; Bisco), Maxcem Elite (MXE; Kerr), RelyX Unicem clicker (UNI; 3M ESPE), seT capsule (SET; SDI), and SmartCem 2 (SC2; Dentsply Caulk). The conventional cement RelyX ARC (3M ESPE) was tested as a reference. The degree of conversion (DC) as a function of time was evaluated by real-time Fourier transform infrared spectroscopy with an attenuated total reflectance (ATR) device. The cements were either photoactivated for 40 seconds (dual-cure mode) or not photoactivated (self-cure mode). The cement film thickness was 50 ± 10 μm. The DC (%) was evaluated 1, 5, 10, 15, 20, 25, and 30 minutes after placing the cement on the ATR cell. Data for DC as a function of time were analyzed by two-way repeated measures analysis of variance (ANOVA). DC values at 30 minutes for the self- and dual-cure modes were submitted to one-way ANOVA. Post hoc comparisons were performed using the Student-Newman-Keuls test (p<0.05). The rate and the extent of conversion were lower for the SARCs compared with the conventional cement. Means ± standard deviations (SD) for the dual-cure mode at 30 minutes were: 75 ± 5 (ARC)a, 73 ± 8 (SET)a, 61 ± 4 (MXE)b, 51 ± 9 (BSC)c, 51 ± 4 (UNI)c, and 48 ± 3 (SC2)c, while in the self-cure mode means and SD were 62 ± 6 (ARC)a, 54 ± 3 (MXE)b, 40 ± 6 (SC2)c, 35 ± 2 (UNI)c, 35 ± 3 (SET)c, and 11 ± 3 (BSC)d. The DC for the dual-cure mode was generally higher than the self-cure, irrespective of the time. Discrepancies in DC between the dual- and self-cure modes from 11% to 79% were observed. In conclusion, SARCs may present slower rate of polymerization and lower final DC than conventional resin cements, in either the dual- or self-cure mode.

Comparative evaluation of surface porosities in conventional heat polymerized acrylic resin cured by water bath and microwave energy with microwavable acrylic resin cured by microwave energy

PubMed Central

Singh, Sunint; Palaskar, Jayant N.; Mittal, Sanjeev

2013-01-01

Background: Conventional heat cure poly methyl methacrylate (PMMA) is the most commonly used denture base resin despite having some short comings. Lengthy polymerization time being one of them and in order to overcome this fact microwave curing method was recommended. Unavailability of specially designed microwavable acrylic resin made it unpopular. Therefore, in this study, conventional heat cure PMMA was polymerized by microwave energy. Aim and Objectives: This study was designed to evaluate the surface porosities in PMMA cured by conventional water bath and microwave energy and compare it with microwavable acrylic resin cured by microwave energy. Materials and Methods: Wax samples were obtained by pouring molten wax into a metal mold of 25 mm × 12 mm × 3 mm dimensions. These samples were divided into three groups namely C, CM, and M. Group C denotes conventional heat cure PMMA cured by water bath method, CM denotes conventional heat cure PMMA cured by microwave energy, M denotes specially designed microwavable acrylic denture base resin cured by microwave energy. After polymerization, each sample was scanned in three pre-marked areas for surface porosities using the optical microscope. As per the literature available, this instrument is being used for the first time to measure the porosity in acrylic resin. It is a reliable method of measuring area of surface pores. Portion of the sample being scanned is displayed on the computer and with the help of software area of each pore was measured and data were analyzed. Results: Conventional heat cure PMMA samples cured by microwave energy showed maximum porosities than the samples cured by conventional water bath method and microwavable acrylic resin cured by microwave energy. Higher percentage of porosities was statistically significant, but well within the range to be clinically acceptable. Conclusion: Within the limitations of this in-vitro study, conventional heat cure PMMA can be cured by microwave energy without compromising on its property such as surface porosity. PMID:24015000

Chemorheology of in-mold coating for compression molded SMC applications

NASA Astrophysics Data System (ADS)

Ko, Seunghyun; Straus, Elliott J.; Castro, Jose M.

2015-05-01

In-mold coating (IMC) is applied to compression molded sheet molding compound (SMC) exterior automotive or truck body panels as an environmentally friendly alternative to make the surface conductive for subsequent electrostatic painting operations. The coating is a thermosetting liquid that when injected onto the surface of the part cures and bonds to provide a smooth conductive surface. In order to optimize the IMC process, it is essential to predict the time available for flow, that is the time before the thermosetting reaction starts (inhibition time) as well as the time when the coating has enough structural integrity so that the mold can be opened without damaging the part surface (cure time). To predict both the inhibition time and the cure time, it is critical to study the chemorheology of IMC. In this paper, we study the chemorheology for a typical commercial IMC system, and show its relevance to both the flow and cure time for the IMC stage during SMC compression molding.

3D Printing by Multiphase Silicone/Water Capillary Inks.

PubMed

Roh, Sangchul; Parekh, Dishit P; Bharti, Bhuvnesh; Stoyanov, Simeon D; Velev, Orlin D

2017-08-01

3D printing of polymers is accomplished easily with thermoplastics as the extruded hot melt solidifies rapidly during the printing process. Printing with liquid polymer precursors is more challenging due to their longer curing times. One curable liquid polymer of specific interest is polydimethylsiloxane (PDMS). This study demonstrates a new efficient technique for 3D printing with PDMS by using a capillary suspension ink containing PDMS in the form of both precured microbeads and uncured liquid precursor, dispersed in water as continuous medium. The PDMS microbeads are held together in thixotropic granular paste by capillary attraction induced by the liquid precursor. These capillary suspensions possess high storage moduli and yield stresses that are needed for direct ink writing. They could be 3D printed and cured both in air and under water. The resulting PDMS structures are remarkably elastic, flexible, and extensible. As the ink is made of porous, biocompatible silicone that can be printed directly inside aqueous medium, it can be used in 3D printed biomedical products, or in applications such as direct printing of bioscaffolds on live tissue. This study demonstrates a number of examples using the high softness, elasticity, and resilience of these 3D printed structures. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

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.

Microtomography of elastomers for tire manufacture

NASA Astrophysics Data System (ADS)

Dunsmuir, John H.; Dias, A. J.; Peiffer, D. G.; Kolb, R.; Jones, G.

1999-09-01

X-ray microtomography is used to image the internal structure of carbon black filled isobutylene-p-methylstyrene-p- bromomethylstyrene (PIB-PMS/BrPMS or ExxProTM) curing bladders before and after use-to-failure in the manufacture of automobile tires. Curing bladders operate under extreme conditions with extended mechanical cycling at high temperatures. Manufacturers typically do not run the bladders until failure but rather a pull policy is established which emphasizes the distribution of cyclic lifetimes. We examine the bladder elastomer structure at a resolution of about 10 microns with the objective of reducing the variability in performance. Using both edge crossing and absorption contrast we identify several types of heterogeneity including voids, foreign inclusions, and the distribution of curative agent from which we infer the uniformity of the cure. The results indicate several potential failure mechanisms. The small number of voids and foreign inclusions are mechanical defects that can initiate cracking. More widespread through the polymer matrix are small regions of polymer devoid of curative agent as shown by absorption edge imaging. These regions may be uncured polymer with poor mechanical and thermal properties that may lead to early failure. After several cure cycles the uncured regions are no longer present in the bladder tread area but they remain near the bead. At high cycles an approximately 500 micrometer thick zinc rich cap develops where the bladder contacts the inner tread area of the tire. This zinc rich cap may cause over-curing of the polymer resulting in crack initiation at the surface of the bladder that contacts the tire.

The Clinical Utilisation of Respiratory Elastance Software (CURE Soft): a bedside software for real-time respiratory mechanics monitoring and mechanical ventilation management.

PubMed

Szlavecz, Akos; Chiew, Yeong Shiong; Redmond, Daniel; Beatson, Alex; Glassenbury, Daniel; Corbett, Simon; Major, Vincent; Pretty, Christopher; Shaw, Geoffrey M; Benyo, Balazs; Desaive, Thomas; Chase, J Geoffrey

2014-09-30

Real-time patient respiratory mechanics estimation can be used to guide mechanical ventilation settings, particularly, positive end-expiratory pressure (PEEP). This work presents a software, Clinical Utilisation of Respiratory Elastance (CURE Soft), using a time-varying respiratory elastance model to offer this ability to aid in mechanical ventilation treatment. CURE Soft is a desktop application developed in JAVA. It has two modes of operation, 1) Online real-time monitoring decision support and, 2) Offline for user education purposes, auditing, or reviewing patient care. The CURE Soft has been tested in mechanically ventilated patients with respiratory failure. The clinical protocol, software testing and use of the data were approved by the New Zealand Southern Regional Ethics Committee. Using CURE Soft, patient's respiratory mechanics response to treatment and clinical protocol were monitored. Results showed that the patient's respiratory elastance (Stiffness) changed with the use of muscle relaxants, and responded differently to ventilator settings. This information can be used to guide mechanical ventilation therapy and titrate optimal ventilator PEEP. CURE Soft enables real-time calculation of model-based respiratory mechanics for mechanically ventilated patients. Results showed that the system is able to provide detailed, previously unavailable information on patient-specific respiratory mechanics and response to therapy in real-time. The additional insight available to clinicians provides the potential for improved decision-making, and thus improved patient care and outcomes.

Quality of dry-cured ham compared with quality of dry-cured shoulder.

PubMed

Reina, Raquel; Sánchez del Pulgar, José; Tovar, Jorge; López-Buesa, Pascual; García, Carmen

2013-08-01

The physicochemical and sensory properties of 30 dry-cured hams and 30 dry-cured shoulders were analyzed to determine the relationships between them. The variables used to characterize both products were: compositional parameters, instrumental texture, amino acid and fatty acid composition, and sensory profile. Despite being products from the same animal and composed mainly of fat, lean, and bone, their morphological differences determine the conditions of the processing time, which produced differences between products in most of the parameters evaluated. Dry-cured shoulders showed lower moisture content and greater instrumental hardness due to their morphology and muscular structure. Besides, these samples showed lower amino acid content according to the shorter ripening time. For the same reason, the dry-cured hams showed higher moisture content, lower instrumental hardness, and higher amino acid content. However, the differences in the muscular structure did not affect the sensory characteristics, which were more related with some compositional parameters, such as chloride, moisture, and amino acid content and with the length of the curing process. © 2013 Extremadura University.

Comparing depth-dependent curing radiant exposure and time of curing of regular and flow bulk-fill composites.

PubMed

Rodrigues, Jose Augusto; Tenorio, Ilana Pais; Mello, Ginger Baranhuk Rabello de; Reis, André Figueiredo; Shen, Chiayi; Roulet, Jean-François

2017-08-21

The effect of restoration depth on the curing time of a conventional and two bulk-fill composite resins by measuring microhardness and the respective radiosity of the bottom surface of the specimen was investigated. 1-, 3- and 5-mm thick washers were filled with Surefil SDR Flow-U (SDR), Tetric EvoCeram Bulk Fill-IVA (TEC) or Esthet-X HD-B1 (EHD), and cured with Bluephase® G2 for 40s. Additional 1-mm washers were filled with SDR, TEC or EHD, placed above the light sensor of MARC®, stacked with pre-cured 1-, 3- or 5-mm washer of respective material, and cured for 2.5~60s to mimic 2-, 4- and 6-mm thick composite curing. The sensor measured the radiosity (EB) at the bottom of specimen stacks. Vickers hardness (VH) was measured immediately at 5 locations with triplicate specimens. Nonlinear regression of VH vs EB by VH=α[1-exp(-EB/β)] with all thickness shows that the values of α, maximum hardness, are 21.6±1.0 kg/mm2 for SDR, 38.3±0.6 kg/mm2 for TEC and 45.3±2.6 kg/mm2 for EHD, and the values of β, rate parameter, are 0.40±0.06 J/cm2 for SDR, 0.77±0.04 J/cm2 for TEC and 0.58±0.09 J/cm2 for EHD. The radiosity of the bottom surface was calculated when the bottom surface of each material attained 80% of α of each material. The curing times for each material are in agreement with manufacturer recommendation for thickness. It is possible to estimate time needed to cure composite resin of known depth adequately by the radiosity and microhardness of the bottom surface.

Chemoviscosity modeling for thermosetting resin systems, 4

NASA Technical Reports Server (NTRS)

Hou, T. H.; Huang, Joan Y. Z.

1989-01-01

An experimental study on the changes of chemorheological properties has been conducted and analyzed on commercial Hercules 3501-6 resin system cured under several isothermal conditions between 375 and 435 K. For the cure temperatures equal to or greater than 385 K, the storage modulus curing curves, G prime (t), exhibited abrupt changes in slope which occurred at various times depending on the curing temperatures and were attributed to the onset of gelation reactions. The crossover points between G prime (t) and G double prime (t) curves were observed for curing temperatures equal to or greater than 400 K. The gelation and the crossover points obtained from the chemorheological measurements, therefore, defined two characteristic resin states during cure. Approximately the same value for the degree of cure was reached by the advancement of the reaction at each of these states. The temperature dependency of the viscosities for the characteristic resin states and the rate constants of increase in moduli at different stages of curing were analyzed. Various G prime (t) and G double prime (t) isothermal curing curves were also shown to be capable of being superimposed on one another by the principle of time-temperature superposition. The resultant shift factors a sub t(t) and a Eta(T) were shown to follow the Arrhenius type relationship. Values of the activation energy suggested that the reaction kinetics, instead of the diffusion mechanism, was the limiting step in the overall resin advancement for the cure at temperatures equal to or greater than 385 K.

Screening and cervical cancer cure: population based cohort study

PubMed Central

Andersson, Therese M-L; Lambert, Paul C; Kemetli, Levent; Silfverdal, Lena; Strander, Björn; Ryd, Walter; Dillner, Joakim; Törnberg, Sven; Sparén, Pär

2012-01-01

Objective To determine whether detection of invasive cervical cancer by screening results in better prognosis or merely increases the lead time until death. Design Nationwide population based cohort study. Setting Sweden. Participants All 1230 women with cervical cancer diagnosed during 1999-2001 in Sweden prospectively followed up for an average of 8.5 years. Main outcome measures Cure proportions and five year relative survival ratios, stratified by screening history, mode of detection, age, histopathological type, and FIGO (International Federation of Gynecology and Obstetrics) stage. Results In the screening ages, the cure proportion for women with screen detected invasive cancer was 92% (95% confidence interval 75% to 98%) and for symptomatic women was 66% (62% to 70%), a statistically significant difference in cure of 26% (16% to 36%). Among symptomatic women, the cure proportion was significantly higher for those who had been screened according to recommendations (interval cancers) than among those overdue for screening: difference in cure 14% (95% confidence interval 6% to 23%). Cure proportions were similar for all histopathological types except small cell carcinomas and were closely related to FIGO stage. A significantly higher cure proportion for screen detected cancers remained after adjustment for stage at diagnosis (difference 15%, 7% to 22%). Conclusions Screening is associated with improved cure of cervical cancer. Confounding cannot be ruled out, but the effect was not attributable to lead time bias and was larger than what is reflected by down-staging. Evaluations of screening programmes should consider the assessment of cure proportions. PMID:22381677

Screening and cervical cancer cure: population based cohort study.

PubMed

Andrae, Bengt; Andersson, Therese M-L; Lambert, Paul C; Kemetli, Levent; Silfverdal, Lena; Strander, Björn; Ryd, Walter; Dillner, Joakim; Törnberg, Sven; Sparén, Pär

2012-03-01

To determine whether detection of invasive cervical cancer by screening results in better prognosis or merely increases the lead time until death. Nationwide population based cohort study. Sweden. All 1230 women with cervical cancer diagnosed during 1999-2001 in Sweden prospectively followed up for an average of 8.5 years. Cure proportions and five year relative survival ratios, stratified by screening history, mode of detection, age, histopathological type, and FIGO (International Federation of Gynecology and Obstetrics) stage. In the screening ages, the cure proportion for women with screen detected invasive cancer was 92% (95% confidence interval 75% to 98%) and for symptomatic women was 66% (62% to 70%), a statistically significant difference in cure of 26% (16% to 36%). Among symptomatic women, the cure proportion was significantly higher for those who had been screened according to recommendations (interval cancers) than among those overdue for screening: difference in cure 14% (95% confidence interval 6% to 23%). Cure proportions were similar for all histopathological types except small cell carcinomas and were closely related to FIGO stage. A significantly higher cure proportion for screen detected cancers remained after adjustment for stage at diagnosis (difference 15%, 7% to 22%). Screening is associated with improved cure of cervical cancer. Confounding cannot be ruled out, but the effect was not attributable to lead time bias and was larger than what is reflected by down-staging. Evaluations of screening programmes should consider the assessment of cure proportions.

Use of fiber reinforced concrete for concrete pavement slab replacement : [summary].

DOT National Transportation Integrated Search

2014-03-01

Replacing cracked concrete in roadways requires : lanes to be closed and traff c disrupted. One way : to reduce road closure time is to reduce concrete : curing time. To accelerate curing time, pavement : engineers mix a very low water-cement ratio w...

Evaluation of curing compound application time on concrete surface durability.

DOT National Transportation Integrated Search

2015-03-01

The effect of curing compound application time after concrete finishing was examined in the study. Times of 30 minutes, 2 hours and 4 hours were considered and repeatability was evaluated with comparisons to a Phase I portion of the study. Scaling re...

Influence of light-curing mode on the cytotoxicity of resin-based surface sealants.

PubMed

Wegehaupt, Florian J; Tauböck, Tobias T; Attin, Thomas; Belibasakis, Georgios N

2014-05-06

Surface sealants have been successfully used in the prevention of erosive tooth wear. However, when multiple tooth surfaces should be sealed, the light-curing procedure is very time-consuming. Therefore, the aim of this study was to investigate whether reduced light-curing time (while maintaining similar energy density) has an influence on resin-based surface sealant cytotoxicity. Bovine dentine discs were treated as follows: group 1: untreated, groups 2-5: Seal&Protect and groups 6-9: experimental sealer. Groups 2 and 6 were light-cured (VALO LED light-curing device) for 40 s (1000 mW/cm2), groups 3 and 7 for 10 s (1000 mW/cm2), groups 4 and 8 for 7 s (1400 mW/cm2) and groups 5 and 9 for 3 s (3200 mW/cm2). Later, materials were extracted in culture medium for 24 h, and released lactate dehydrogenase (LDH) activity as a measure of cytotoxicity was determined photometrically after cells (dental pulp cells and gingival fibroblasts) were exposed to the extracts for 24 h. Three independent experiments, for both sample preparation and cytotoxicity testing, were performed. Overall, lowest cytotoxicity was observed for the unsealed control group. No significant influence of light-curing settings on the cytotoxicity was observed (p = 0.537 and 0.838 for pulp cells and gingival fibroblasts, respectively). No significant difference in the cytotoxicity of the two sealants was observed after light-curing with same light-curing settings (group 2 vs. 6, 3 vs. 7, 4 vs. 8 and 5 vs. 9: p > 0.05, respectively). Shortening the light-curing time, while maintaining constant energy density, resulted in no higher cytotoxicity of the investigated sealants.

Effect of curing time on the physicochemical and sensory properties of beef jerky replaced salt with soy sauce, red pepper paste and soybean paste.

PubMed

Lim, H J; Kim, G D; Jung, E Y; Seo, H W; Joo, S T; Jin, S K; Yang, H S

2014-08-01

This study was done to investigate the quality properties of beef jerky with soy sauce, red pepper paste, and soybean paste replacing salt. Sliced beef samples were cured in salt (control), soy sauce, red pepper paste, and soybean paste for 24 or 48 h and then dried at 70°C for 8 h. Treatments showed higher final moisture content and lower Na(+) concentration than the control after drying for 8 h. The lightness and shear force values were lower in all treatment samples than in the control during 48 h of curing time. In particular, lower lipid oxidation was found in the jerky cured with red pepper paste than in the control. Sensory evaluation showed that color, flavor, and tenderness of jerky samples were improved by replacing salt with soy sauce, red pepper paste and soybean paste, and higher likeability scores of the beef jerky were obtained among those treatments after 48 h of curing time.

Multi-state models for colon cancer recurrence and death with a cured fraction.

PubMed

Conlon, A S C; Taylor, J M G; Sargent, D J

2014-05-10

In cancer clinical trials, patients often experience a recurrence of disease prior to the outcome of interest, overall survival. Additionally, for many cancers, there is a cured fraction of the population who will never experience a recurrence. There is often interest in how different covariates affect the probability of being cured of disease and the time to recurrence, time to death, and time to death after recurrence. We propose a multi-state Markov model with an incorporated cured fraction to jointly model recurrence and death in colon cancer. A Bayesian estimation strategy is used to obtain parameter estimates. The model can be used to assess how individual covariates affect the probability of being cured and each of the transition rates. Checks for the adequacy of the model fit and for the functional forms of covariates are explored. The methods are applied to data from 12 randomized trials in colon cancer, where we show common effects of specific covariates across the trials. Copyright © 2013 John Wiley & Sons, Ltd.

Dynamic measurement of local displacements within curing resin-based dental composite using optical coherence elastography

NASA Astrophysics Data System (ADS)

Tomlins, Peter H.; Rahman, Mohammed Wahidur; Donnan, Robert S.

2016-04-01

This study aimed to determine the feasibility of using optical coherence elastography to measure internal displacements during the curing phase of a light-activated, resin-based composite material. Displacement vectors were spatially mapped over time within a commercial dental composite. Measurements revealed that the orientation of cure-induced displacement vectors varied spatially in a complex manner; however, each vector showed a systematic evolution with time. Precision of individual displacements was estimated to be ˜1 to 2 μm, enabling submicrometer time-varying displacements to be detected.

Comparison of the heat generation of light curing units.

PubMed

Bagis, Bora; Bagis, Yildirim; Ertas, Ertan; Ustaomer, Seda

2008-02-01

The aim of this study was to evaluate the heat generation of three different types of light curing units. Temperature increases were recorded from a distance of 1 mm from a thermocouple to the tip of three different types of light curing units including one quartz-tungsten halogen (QTH), one plasma arc (PAC), and one light emitting diode (LED) unit. An experimental model was designed to fix the 1 mm distance between the tip of the light curing units and the thermocouple wire. Temperature changes were recorded in 10 second intervals up to 40 seconds. (10, 20, 30, and 40 seconds). Temperature measurements were repeated three times for every light curing unit after a one hour standby period. Statistical analysis of the results was performed using the analysis of variance (ANOVA) and the Bonferroni Test. The highest temperature rises (54.4+/-1.65 degrees C) occurred during activation of a PAC light curing unit for every test period (p<.05). The least temperature increase (11.8+/-1.3 degrees C) occurred with a LED curing unit for each tested period except for the measurement of the temperature rise using the QTH curing unit at the tenth second interval (p<.05). These results indicate the choice of light activation unit and curing time is important when polymerizing light activated resin based restorations to avoid any thermal damage to the pulp.

Effect of mold diameter on the depth of cure of a resin-based composite material.

PubMed

Erickson, Robert L; Barkmeier, Wayne W

2017-02-01

The purpose of this study was to examine the effect of mold diameter on depth of cure of a resin-based composite material for varying amounts of irradiation. A resin-based composite was light-cured for 10-80 s in stainless-steel molds of either 6 mm or 4 mm in diameter and then dark-stored for 24 h. Specimens were then scraped back and the length of the cured specimens was measured to provide depth of cure (D SB ). Radiant exposure to each of the mold diameters was determined by measuring the power. The D SB values using the 4-mm molds were lower than those of the 6-mm molds. The average difference between the two groups for each irradiation time was 0.45 ± 0.02 mm. A fixed depth of cure required about 39% more irradiation time for the 4-mm mold than for the 6-mm mold but 75% more radiant exposure. The difference in cure depth for a fixed radiant exposure was 0.79 mm. A better comparison of depth of cure is obtained by using identical radiant exposures for different mold diameters. It is believed that greater loss of light by absorption at the stainless-steel cylinder walls for the 4-mm-diameter cylinders accounts for the lower depth of cure when compared with the 6-mm molds. © 2017 Eur J Oral Sci.

Creatine and creatinine evolution during the processing of dry-cured ham.

PubMed

Mora, Leticia; Hernández-Cázares, Aleida S; Sentandreu, Miguel Angel; Toldrá, Fidel

2010-03-01

Dry-curing of ham involves many biochemical reactions that depend on the processing conditions. The aim of this study was to evaluate the effect of the dry-cured processing on the concentration of creatine, creatinine and the creatinine/creatine ratio. Dry-cured hams under study were salted using three different salt mixtures (100% NaCl; NaCl and KCl at 50% each; and 55% NaCl, 25% KCl, 15% CaCl(2) and 5% MgCl(2)) in order to observe its influence on creatinine formation but no significant differences were found between them at any time of processing. However, significant differences between different post-salting times (20, 50 and 80 days) and the ripened hams (7, 9 and 11 months of ripening) were observed. Results showed that creatine and creatinine remain stable once the ripening period is reached. These results were confirmed when analysing dry-cured ham samples submitted to extreme conditions of temperature and time (20, 30, 40 and 70 degrees C during 0, 20, 40 and 60 min) as well as commercial dry-cured hams with more than 12 months of processing. Copyright 2009 Elsevier Ltd. All rights reserved.

A Novel Approach to Monitoring the Curing of Epoxy in Closed Tools by Use of Ultrasonic Spectroscopy

PubMed Central

2017-01-01

The increasing use of composite materials has led to a greater demand for efficient curing cycles to reduce costs and speed up production cycles in manufacturing. One method to achieve this goal is in-line cure monitoring to determine the exact curing time. This article proposes a novel method through which to monitor the curing process inside closed tools by employing ultrasonic spectroscopy. A simple experiment is used to demonstrate the change in the ultrasonic spectrum during the cure cycle of an epoxy. The results clearly reveal a direct correlation between the amplitude and state of cure. The glass transition point is indicated by a global minimum of the reflected amplitude. PMID:29301222

GLASS TRANSITION AND DEGREE OF CONVERSION OF A LIGHT-CURED ORTHODONTIC COMPOSITE

PubMed Central

Sostena, Michela M. D. S.; Nogueira, Renata A.; Grandini, Carlos R.; Moraes, João Carlos Silos

2009-01-01

Objective: This study evaluated the glass transition temperature (Tg) and degree of conversion (DC) of a light-cured (Fill Magic) versus a chemically cured (Concise) orthodontic composite. Material and Methods: Anelastic relaxation spectroscopy was used for the first time to determine the Tg of a dental composite, while the DC was evaluated by infrared spectroscopy. The light-cured composite specimens were irradiated with a commercial LED light-curing unit using different exposure times (40, 90 and 120 s). Results: Fill Magic presented lower Tg than Concise (35-84°C versus 135°C), but reached a higher DC. Conclusions: The results of this study suggest that Fill Magic has lower Tg than Concise due to its higher organic phase content, and that when this light-cured composite is used to bond orthodontic brackets, a minimum energy density of 7.8 J/cm2 is necessary to reach adequate conversion level and obtain satisfactory adhesion. PMID:20027428

[Consideration of the concepts of "remission" and "cured" in schizophrenia: a male case who experienced schizophrenia with psycho-motoric excitation 30 years ago].

PubMed

Sekine, Yoshio

2005-01-01

Since the era of Kraepelin and Bleuler, schizophrenia has been considered to be very difficult to cure. Even if all symptoms of its acute phase have disappeared completely, it is customary to use the terms say "remission" instead of "cured". The chief reason why they have been unwilling to say "cured" is that, even if the present state seems to be "cured", there will be surely another attack in near future, so, the non-symptomatic state should not be understood as "cured". Whether schizophrenic patients can be cured or not is one of the great problems of modern psychiatry. Is there no probability for them to be cured? Recently, after a 30 years gap, I came to meet a man who had had a schizophrenic attack of the psychomotoric type when he was 25 years old and had been sent to the mental hospital where I had been at work and, by chance, had engaged in his treatment. After about 5 months' of acute state, he came at, so to speak, "Residualzustand" (Conrad) for about 1 year and then got insight into his psychosis. After the discharge, he had visited me as an outpatient once a month regularly. About one year thereafter, the change of my work place made us separate from each other. Since then, he stopped visiting the doctor and also stopped taking anti-psychotic drugs. He married at 29 years old and had 2 daughters and a son. In addition, he had started to work for his father's business. After his father's death, he became the owner of 5 shops and the supervisor of 50 workers. Is he not yet "cured"? Is he only in the state of "remission" even now? According to the principle of Kraepelin and Bleuler, he is not "cured" yet, because he will surely have a psychotic exacerbation in future. I wonder then, what is the difference of the two concepts of "remission" and "cured", and how is it possible to change "remission" to "cured"? Even Bleuler, E. has written in his world-famous textbook that the longer the duration of remission after the last attack, the smaller the probability of the next attack, and that after about 5 years free of attack, another exacerbation would be very improbable. Supported by the experiences of Utena, Miya and so forth, I proposed a thesis that if a person who had undergone schizophrenic attack has been in complete remission for more than 10 years, he can surely be counted as "cured". To verify this probability about the outcome of schizophrenia, it is very important for us to observe any patient who has attained the state of complete remission, and to describe and report his state thereafter as long enough as

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. Copyright © 2013 Elsevier Ltd. All rights reserved.

CaP CURE Initiatives and Projects

PubMed Central

Soule, Howard R

2003-01-01

CaP CURE was founded in 1993 to help find better treatments and a cure for prostate cancer. By reducing the time and complexity required to apply for funding, and by funding many first-time applicants, CaP CURE has attracted a large number of high-level investigators to the field of prostate cancer research. The organization’s Therapy Consortium meets regularly to address major issues that impede progress in clinical development of new treatments for prostate cancer. CaP CURE has also sponsored an initiative to standardize clinical trial design scenarios for the clinical state of rising prostate-specific antigen and intends to present them to the Food and Drug Administration in partnership with the National Dialogue on Cancer. Finally, CaP CURE’s efforts have resulted in a significant increase in federal funding of prostate cancer research programs. PMID:16986049

Shear bond strength of orthodontic color-change adhesives with different light-curing times

PubMed Central

Bayani, Shahin; Ghassemi, Amirreza; Manafi, Safa; Delavarian, Mohadeseh

2015-01-01

Background: The purpose of this study was to evaluate the effect of light-curing time on the shear bond strength (SBS) of two orthodontic color-change adhesives (CCAs). Materials and Methods: A total of 72 extracted premolars were randomly assigned into 6 groups of 12 teeth each. Subsequent to primer application, a metal bracket was bonded to the buccal surface using an orthodontic adhesive. Two CCAs (Greengloo and Transbond Plus) were tested and one conventional light-cured adhesive (Resilience) served as control. For each adhesive, the specimens were light-cured for two different times of 20 and 40 s. All the specimens underwent mechanical testing using a universal testing machine to measure the SBS. Adhesive remnant index (ARI) was used to assess the remnant adhesive material on the tooth surface. All statistical analyses were performed using SPSS software. The significance level for all statistical tests was set at P ≤ 0.05. Results: The SBSs of the tested groups were in the range of 14.05-31.25 MPa. Greengloo adhesive showed the highest SBS values when light-cured for 40 s, and Transbond Plus adhesive showed the lowest values when light-cured for 20 s. ARI scores of Transbond Plus adhesive were significantly higher than those of controls, while other differences in ARI values were not significant. Conclusion: Within the limitations of his study, decreasing the light-curing time from 40 to 20 s decreased the SBS of the tested adhesives; however, this decline in SBS was statistically significant only in Transbond Plus adhesive PMID:26005468

Surgical cure rates of sporadic medullary thyroid cancer in the era of calcitonin screening.

PubMed

Machens, Andreas; Dralle, Henning

2016-09-01

Time trends of the extent of disease at first diagnosis and biochemical cure remain ill-defined for sporadic medullary thyroid cancer (MTC). This investigation aimed to delineate time trends and biochemical cure rates for sporadic MTC. This was an observational study of consecutive patients operated on for sporadic MTC between 1995 and 2015. Time trends of clinical and histopathological variables indicative of the extent of disease and biochemical cure were calculated for 600 patients with sporadic MTC, 322 of whom had initial neck surgery and 278 of whom had neck reoperation at a tertiary surgical center in Germany. From 1995-2000 to 2011-2015, significant declines (all P<0.001) were noted in the percentage of node-positive tumors (from 73 to 49%), mediastinal lymph node metastasis (from 21 to 6%) and distant metastasis (from 23 to 6%). These changes were paralleled by significant increases (all P<0.001) in mean patient age (from 49.1 to 57.3years) and the percentage of MTC ≤10mm (from 19 to 39%) and biochemical cure (from 28 to 62%). When only patients with primary tumors >10mm were considered, the decreasing percentage of mediastinal lymph node metastasis and distant metastasis, and rising mean patient age and biochemical cure rates remained statistically significant. Significant reductions in the extent of the disease and improved biochemical cure rates pointed toward increasing therapeutic control of sporadic MTC. The independent contribution of routine calcitonin screening to these time-dependent changes warrants more research. © 2016 European Society of Endocrinology.

Effect of light-curing units, post-cured time and shade of resin cement on knoop hardness.

PubMed

Reges, Rogério Vieira; Costa, Ana Rosa; Correr, Américo Bortolazzo; Piva, Evandro; Puppin-Rontani, Regina Maria; Sinhoreti, Mário Alexandre Coelho; Correr-Sobrinho, Lourenço

2009-01-01

The aim of this study was to evaluate the Knoop hardness after 15 min and 24 h of different shades of a dual-cured resin-based cement after indirect photoactivation (ceramic restoration) with 2 light-curing units (LCUs). The resin cement Variolink II (Ivoclar Vivadent) shade XL, A2, A3 and opaque were mixed with the catalyst paste and inserted into a black Teflon mold (5 mm diameter x 1 mm high). A transparent strip was placed over the mold and a ceramic disc (Duceram Plus, shade A3) was positioned over the resin cement. Light-activation was performed through the ceramic for 40 s using quartz-tungsten-halogen (QTH) (XL 2500; 3M ESPE) or light-emitting diode (LED) (Ultrablue Is, DMC) LCUs with power density of 615 and 610 mW/cm(2), respectively. The Koop hardness was measured using a microhardness tester HMV 2 (Shimadzu) after 15 min or 24 h. Four indentations were made in each specimen. Data were subjected to ANOVA and Tukey's test (alpha=0.05). The QTH LCU provided significantly higher (p<0.05) KHN values than the LED LCU. When the post-cure times were compared for the same shade, QTH and LED at 24 h provided significantly higher (p<0.05) KHN values than at 15 min. It may be concluded that the Knoop hardness was generally dependent on the LCU and post-cure time. The opaque shade of the resin cement showed lower Knoop hardness than the other shades for both LCUs and post-cure times.

Polyacrylonitrile/Carbon Nanotube Composite: Precursor for Next Generation Carbon Fiber

DTIC Science & Technology

2010-02-23

difficult to get the accurate time for the end of reactions. The curing process of thermosetting materials has been widely studied by investigating...Ramis X, Cadenato A, Morancho JM, Salla JM. Curing of a thermosetting powder coating by means of DMTA, TMA and DSC. Polymer. 2003;44(7):2067-79. [17...Cadenato A, Salla JM, Ramis X, Morancho JM, Marroyo LM, Martin JL. Determination of gel and vitrification times of thermoset curing process by means of

The Effect on Final Bond Strength of Bracket Manipulation Subsequent To Initial Positioning

NASA Astrophysics Data System (ADS)

Beebe, David A.

The shear bond strength of light activated orthodontic adhesives varies according to the composition of the material, placement protocol, and time prior to light curing. Manipulating brackets after their initial placement on a tooth can disrupt the adhesive's polymerization and compromise final bond strength. No previous research has investigated how a specific degree of manipulation, and the amount of time elapsed prior to curing, under specific lighting conditions, affects the orthodontic adhesives shear bond strength. Victory SeriesRTM, MBT prescription, premolar (3M Unitek, Monrovia, CA) orthodontic brackets were bonded using three different adhesives to sixty (60) bicuspids and varying the time after bracket manipulation before curing. The shear bond strength was calculated for each specimen. The brackets were debonded and the same teeth were rebonded with new, identical brackets, using the same protocol and under the same conditions. The results showed a statistically significant difference between the shear bond strength of Transbond XT and Grengloo, with Transbond XT having the highest strength. There was also a statistically significance difference in bond strength between the group cured 30 seconds after manipulation and the groups manipulated at different intervals prior to curing, with the 30 second group having the highest bond strength. This study confirms that various orthodontic adhesives have different bond strengths depending on manipulation and varying times prior to curing each adhesive.

A simple technique to prolong molding time during application of a fiberglass cast: An in vitro study

PubMed Central

Ayzenberg, Mark; Narvaez, Michael; Raphael, James

2018-01-01

Casting is routinely used for acute and post-operative immobilization and remains a cornerstone in the non-operative management of fractures and deformities. The application of a properly fitted and wellmolded cast, especially for a trainee, can be challenging. We present a simple method of prolonging cure time of fiberglass cast — placing ice in the dip water. Eight-ply, fiveinch fiberglass cast was circumferentially applied to an aluminum-wrapped cardboard cylinder. An electronic, 2-channel temperature sensor (TR-71wf Temp Logger, T&D Corporation, Matsumoto, Japan), accurate to 0.1ºC and accurate to ±0.3ºC, was placed between the fourth and fifth layers of fiberglass. Thirty total casts were tested using 9±1ºC (cold), 22±1ºC (ambient), and 36±1ºC (warm) dip water. Room temperature was maintained at 24±1ºC. Cast temperatures were measured during the exothermic reaction generated by the cast curing. Peak temperatures and cure times were recorded. Cure time was defined as the point of downward deflection on the timetemperature curve immediately after peak. Cure and peak temperatures were compared among groups using analysis of variance. Mean cure time was 3.5±0.1 minutes for warm water, 5.0±0.4 minutes for ambient water and 7.0±0.5 minutes for cold water. Peak temperature, measured between layers 4 and 5 of the cast material, was 36.6±0.8ºC for warm water, 31.1±1.4ºC for ambient water and 25.2±0.5ºC for cold water. Cold afforded, on average, an additional 2 minutes (40% increase) in cure time compared to ambient water and an additional 3.5 minutes (100% increase) compared to warm water. Cure time differences were significant (P<0.001) for all groups, as were peak temperature differences (P<0.001). Temperatures concerning for development of burns were never reached. Utilizing iced dip water when casting is a simple and effective method to prolong the time available for cast application. Orthopedic residents and trainees may find this useful in learning to fabricate a high quality cast. For the experienced orthopedic surgeon, this method eliminates the need to bridge longlimb casts and facilitates the application of complex casts. PMID:29770174

[In vitro study of the flow duration of antibiotics solutions prepared in elastomeric infusion devices: effect of cold storage for 3 to 7days].

PubMed

Grangeon-Chapon, C; Robein-Dobremez, M-J; Pin, I; Trouiller, P; Allenet, B; Foroni, L

2015-09-01

Within the cystic fibrosis patients' home care, EMERAA network ("Together against Cystic fibrosis in Rhone-Alpes and Auvergne") organizes parenteral antibiotics cures at home prepared in elastomeric infusion devices by hospital pharmacies. However, patients and nurses found that the durations of infusion with these devices were often longer than the nominal duration of infusion indicated by their manufacturer. This study aimed to identify the potential different causes in relation to these discordances. Three hundred and ninety devices of two different manufacturers are tested in different experimental conditions: three antibiotics each at two different doses, duration of cold storage (three days or seven days) or immediate tests without cold storage, preparation and storage of the solution in the device (protocol Device) or transfer in the device just before measurement (protocol Pocket). All tests highlighted a longer flow duration for devices prepared according to the protocol Device versus the protocol Pocket (P=0.004). Flow duration is increased in the case of high doses of antibiotics with high viscosity such as piperacilline/tazobactam. The results of this in vitro study showed the impact of: (1) the time between the filling of the device and the flow of the solution; (2) cold storage of elastomeric infusion devices; (3) concentration of antibiotics and therefore the viscosity of the solution to infuse. It is therefore essential that health care teams are aware of factors, which may lead to longer infusion durations with these infusion devices. When the additional time for infusion remain acceptable, it should be necessary to inform the patient and to relativize these lengthening compared to many benefits that these devices provide for home care. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Analysis of rheological properties of bone cements.

PubMed

Nicholas, M K D; Waters, M G J; Holford, K M; Adusei, G

2007-07-01

The rheological properties of three commercially available bone cements, CMW 1, Palacos R and Cemex ISOPLASTIC, were investigated. Testing was undertaken at both 25 and 37 degrees C using an oscillating parallel plate rheometer. Results showed that the three high viscosity cements exhibited distinct differences in curing rate, with CMW 1 curing in 8.7 min, Palacos R and Cemex ISOPLASTIC in 13 min at 25 degrees C. Furthermore it was found that these curing rates were strongly temperature dependent, with curing rates being halved at 37 degrees C. By monitoring the change of viscosity with time over the entire curing process, the results showed that these cements had differing viscosity profiles and hence exhibit very different handling characteristics. However, all the cements reached the same maximum viscosity of 75 x 10(3) Pa s. Also, the change in elastic/viscous moduli and tan delta with time, show the cements changing from a viscous material to an elastic solid with a clear peak in the viscous modulus during the latter stages of curing. These results give valuable information about the changes in rheological properties for each commercial bone cement, especially during the final curing process.

Patient Race and Outcome Preferences as Predictors of Urologists Treatment Recommendations and Referral Patterns in Early-Stage Prostate Cancer

DTIC Science & Technology

2006-11-01

option for cure [12]. Although African Americans are more likely to fear surgery and distrust physicians than members of other racial/ethnic groups...disadvantaged patients are less appropriate for surgery . Such patients might be more likely to experience postoperative complications and require longer...Center, Denver, Colorado 80262. phone: 303-372-9432; e-mail: tom.denberg@uchsc.edu Key words: surgery ; prostatectomy; surgical volume; postoperative

Short communication: pre- and co-curing effect of adhesives on shear bond strengths of composite resins to primary enamel and dentine: an in vitro study.

PubMed

Viswanathan, R; Shashibhushan, K K; Subba Reddy, V V

2011-12-01

To evaluate and compare shear bond strengths of composite resins to primary enamel and dentine when the adhesives are pre-cured (light cured before the application of the resin) or co-cured (adhesive and the resin light cured together). Buccal surfaces of 80 caries-free primary molars were wet ground to create bonding surfaces on enamel and dentine and specimens mounted on acrylic blocks. Two bonding agents (Prime and Bond NT® and Xeno III®) were applied to either enamel or dentine as per manufacturer's instructions. In 40 specimens, the bonding agent was light cured immediately after the application (pre-cured). The other 40 specimens were not light cured until the composite resin application (co-cured). Resin composite cylinders were made incrementally using acrylic moulds over the adhesives and light cured. Specimens were stored in deionised water for 24 hours at room temperature. Shear bond strength was measured using an Instron universal testing machine (in MPa) and was analysed with Student's unpaired t test. Light curing the adhesive separately produced significantly higher bond strengths to primary dentine than co-curing (p<0.001). At the same time light curing the adhesive separately did not produce significantly different bond strengths to primary enamel (p>0.05). Curing sequence had no significant effect on shear bond strength of adhesives on the primary enamel. Pre-curing adhesives before curing composite resins produced greater shear bond strength to primary dentine.

[Resin-modified glass-ionomers in dentistry].

PubMed

Gladys, S; Van Meerbeek, B; Braem, M; Lambrechts, P; Vanherle, G

1996-11-01

The resin-modified glass-ionomers contain the essential components of both a conventional glass-ionomer and a visible light-cured resin. They have several advantages like longer working time, shorter setting time, bonding to tooth structure, fluoride-release, better aesthetics than conventional glass-ionomers and ease in use. As disadvantages can be mentioned the polymerisation shrinkage, trapping of air-bubbles, difficulties in colour choice and contouring. A physical and mechanical characterisation was necessary to define the possibilities and limits of these materials. It can be stated that the strength and aesthetic appearance of resin-modified glass-ionomers are less than that of composites, but better than that of conventional glass-ionomers. Clinically, this is expressed in a rough and dull surface compared to a composite restoration. They are not indicated in stress bearing areas. Consequently, they are mainly indicated in cervical class V-restorations in the postcanine region, and probably restorations in pedodontics, geriatric dentistry and for patients with a high caries activity.

Randomized controlled study of MONARC® vs. tension-free vaginal tape obturator (TVT-O®) in the treatment of female urinary incontinence: comparison of 3-year cure rates.

PubMed

Park, Yoo Jun; Kim, Duk Yoon

2012-04-01

Transobturator approaches to midurethral sling surgery are one of the most commonly performed operations for female stress urinary incontinence throughout the world. However, very few results of randomized clinical trials of transobturator midurethral sling surgery (MONARC vs. TVT-O) for the treatment of female urinary incontinence have been reported. In this study, we compared the 3-year follow-up cure rates of these two procedures. From July 2006 to June 2008, 74 patients who had undergone MONARC (35 patients) or TVT-O (39 patients) were included in the study and were analyzed prospectively. The mean follow-up duration of both groups was 39.2 months. Preoperative and postoperative evaluations included physical examination, uroflowmetry and postvoid residual measurement, involuntary urine loss with physical activity, and urinary symptoms. Cure of female urinary incontinence was defined as patient report of no loss of urine upon physical activity. The patients' satisfaction after treatment was rated as very satisfied, satisfied, equivocal, and unsatisfied. Very satisfied and satisfied were considered as the satisfied rate. There were no significant differences in preoperative patient characteristics, postoperative complications, or success rate between the two groups. The cure rate of the MONARC and TVT-O groups was 85.7% and 84.6%, respectively. The patient satisfaction (very satisfied, satisfied) rate of the MONARC and TVT-O groups was 82.8% and 82.1%, respectively. The MONARC and TVT-O procedures were equally efficient for the treatment of female urinary incontinence, with maintenance of high cure rates for 3 years. Longer follow-up is needed to confirm these results.

Randomized Controlled Study of MONARC® vs. Tension-free Vaginal Tape Obturator (TVT-O®) in the Treatment of Female Urinary Incontinence: Comparison of 3-Year Cure Rates

PubMed Central

Park, Yoo Jun

2012-01-01

Purpose Transobturator approaches to midurethral sling surgery are one of the most commonly performed operations for female stress urinary incontinence throughout the world. However, very few results of randomized clinical trials of transobturator midurethral sling surgery (MONARC vs. TVT-O) for the treatment of female urinary incontinence have been reported. In this study, we compared the 3-year follow-up cure rates of these two procedures. Materials and Methods From July 2006 to June 2008, 74 patients who had undergone MONARC (35 patients) or TVT-O (39 patients) were included in the study and were analyzed prospectively. The mean follow-up duration of both groups was 39.2 months. Preoperative and postoperative evaluations included physical examination, uroflowmetry and postvoid residual measurement, involuntary urine loss with physical activity, and urinary symptoms. Cure of female urinary incontinence was defined as patient report of no loss of urine upon physical activity. The patients' satisfaction after treatment was rated as very satisfied, satisfied, equivocal, and unsatisfied. Very satisfied and satisfied were considered as the satisfied rate. Results There were no significant differences in preoperative patient characteristics, postoperative complications, or success rate between the two groups. The cure rate of the MONARC and TVT-O groups was 85.7% and 84.6%, respectively. The patient satisfaction (very satisfied, satisfied) rate of the MONARC and TVT-O groups was 82.8% and 82.1%, respectively. Conclusions The MONARC and TVT-O procedures were equally efficient for the treatment of female urinary incontinence, with maintenance of high cure rates for 3 years. Longer follow-up is needed to confirm these results. PMID:22536469

Role of the 85-Kilobase Plasmid and Plasmid-Encoded Virulence-Associated Protein A in Intracellular Survival and Virulence of Rhodococcus equi

PubMed Central

Giguère, Steeve; Hondalus, Mary K.; Yager, Julie A.; Darrah, Patricia; Mosser, David M.; Prescott, John F.

1999-01-01

Rhodococcus equi is a facultative intracellular pathogen of macrophages and a cause of pneumonia in young horses (foals) and immunocompromised people. Isolates of R. equi from pneumonic foals typically contain large, 85- or 90-kb plasmids encoding a highly immunogenic virulence-associated protein (VapA). The objective of this study was to determine the role of the 85-kb plasmid and VapA in the intracellular survival and virulence of R. equi. Clinical isolates containing the plasmid and expressing VapA efficiently replicated within mouse macrophages in vitro, while plasmid-cured derivatives of these organisms did not multiply intracellularly. An isolate harboring the large plasmid also replicated in the tissues of experimentally infected mice, whereas its plasmid-cured derivative was rapidly cleared. All foals experimentally infected with a plasmid-containing clinical isolate developed severe bronchopneumonia, whereas the foals infected with its plasmid-cured derivative remained asymptomatic and free of visible lung lesions. By day 14 postinfection, lung bacterial burdens had increased considerably in foals challenged with the plasmid-containing clinical isolate. In contrast, bacteria could no longer be cultured from the lungs of foals challenged with the isogenic plasmid-cured derivative. A recombinant, plasmid-cured derivative expressing wild-type levels of VapA failed to replicate in macrophages and remained avirulent for both mice and foals. These results show that the 85-kb plasmid of R. equi is essential for intracellular replication within macrophages and for development of disease in the native host, the foal. However, expression of VapA alone is not sufficient to restore the virulence phenotype. PMID:10377138

Aging Studies of VCE Dismantlement Returns

DOE Office of Scientific and Technical Information (OSTI.GOV)

Letant, S; Alviso, C; Pearson, M

2011-10-17

VCE is an ethylene/vinyl acetate/vinyl alcohol terpolymer binder for filled elastomers which is designed to accept high filler loadings. Filled elastomer parts consist of the binder (VCE), a curing agent (Hylene MP, diphenol-4-4{prime}-methylenebis(phenylcarbamate)), a processing aid (LS, lithium stearate), and filler particles (typically 70% fraction by weight). The curing of the filled elastomer parts occurs from the heat-activated reaction between the hydroxyl groups of VCE with the Hylene MP curing agent, resulting in a cross-linked network. The final vinyl acetate content is typically between 34.9 and 37.9%, while the vinyl alcohol content is typically between 1.27 and 1.78%. Surveillance datamore » for this material is both scarce and scattered, complicating the assessment of any aging trends in systems. In addition, most of the initial surveillance efforts focused on mechanical properties such as hardness and tensile strength, and chemical information is therefore lacking. Material characterization and aging studies had been performed on previous formulations of the VCE material but the Ethylene Vinyl Acetate (EVA) starting copolymer is no longer commercially available. New formulations with replacement EVA materials are currently being established and will require characterization as well as updated aging models.« less

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.

Evaluation of increased milking frequency as an additional treatment for cows with clinical mastitis.

PubMed

Krömker, Volker; Zinke, Claudia; Paduch, Jan-Hendrik; Klocke, Doris; Reimann, Anette; Eller, Georg

2010-02-01

This field study focused on the possible effects of increased milking frequency (milking four times a day in comparison with milking twice a day) on clinical and bacteriological cure rates of clinical, antibiotically treated mastitis cases. Parameters tested were clinical, microbiological and full (cytomicrobiological) cure as well as the development of milk yield after the clinical mastitis episode. Cows from a large dairy herd meeting the study criteria (n=93) were assigned to two treatment groups by a systematic randomization scheme (blocked by body temperature <=or >39.5 degrees C). Both groups were randomly divided by experimental treatments: a) antibiotic intramammary treatment and milking 2-times a day; b) antibiotic intramammary treatment and milking 4-times a day. Treatments were initiated before the culture results were known. Cows were surveyed and evaluated on days 1-6, 24 and 31. No significant differences between treatment and control groups regarding clinical cure, microbiological cure, full cure and milk production could be established. Applying a 4-times a day milking regime did not lead to any significant effect, either positive or negative. Therefore, the results suggest that milking 4-times a day as a supporting therapy for mild, moderate and severe antimicrobially treated mastitis cases cannot be recommended.

Electron beam curing — taking good ideas to the manufacturing floor

NASA Astrophysics Data System (ADS)

Saunders, C.; Lopata, V.; Barnard, J.; Stepanik, T.

2000-03-01

Acsion is exploiting several emerging electron beam EB applications ranging from composite curing and repair to viscose manufacturing. EB curing of composite structures offers several advantages: significantly reduced curing times; improvements in part quality and performance; reduced environmental and health concerns; improvements in material handling; and reduced overall manufacturing costs compared to thermal curing. The aerospace industry is developing EB technology in all of their market sectors, including military aviation and space products. Some specific products include cryogenic fuel tanks, improved canopy frames for jet aircraft, and the all-composite military aircraft. This paper discusses each of these opportunities.

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).

HIV cure research in South Africa: a preliminary exploration of stakeholder perspectives.

PubMed

Moodley, Keymanthri; Staunton, Ciara; de Roubaix, Malcolm; Cotton, Mark

2016-01-01

Innovative strategies for HIV cure are in development and research studies are being designed and planned globally. South Africa is no exception. However, little is known about stakeholders' knowledge, understanding and expectations of future cure research. This study aimed to obtain in-depth qualitative insights into stakeholder perspectives at this formative stage of HIV cure research. Fifteen stakeholders were interviewed in an HIV research clinic in the Western Cape, South Africa with their consent. Interviews were transcribed verbatim and analysed using thematic content analysis. Broad themes that emerged included the meaning of cure, awareness of HIV cure research, risks and benefits of such research. General awareness and understanding of HIV cure research was lower than expected. Some participants expressed a fatalistic attitude to HIV and described it as an "end-time illness" with no prospect of cure. In general, HIV cure research was regarded as risky - biologically psychologically and socially. If study designs were to include treatment interruption, participants would comply only if success was guaranteed. Given these perceptions of HIV cure research, significant challenges to consent processes and participant recruitment can be anticipated. Authentic community engagement and intensive educational interventions will be necessary prior to future cure research in South Africa.

Effect of energy density and delay time on the degree of conversion and Knoop microhardness of a dual resin cement.

PubMed

Mainardi, Maria do Carmo A J; Giorgi, Maria Cecília C; Lima, Débora A N L; Marchi, Giselle M; Ambrosano, Gláucia M; Paulillo, Luiz A M S; Aguiar, Flávio H B

2015-02-01

In the present study, we evaluated the influence of the photo-curing delay time and energy density on the degree of conversion and the Knoop microhardness of a resin cement. Seventy-eight samples were assigned to 13 groups (n = 6), one of which received no light curing (control). The samples were made of a dual-cured resin cement (RelyX ARC) with the aid of a Teflon matrix, submitted to one of the following energy densities (J/cm²): 7, 14, 20, and 28. Delay times were immediate (0), 1 min, or 2 min. After 24 h, the degree of conversion and microhardness were measured at three segments: cervical, medium, and apical. Data were submitted to three-way anova and Tukey's and Dunnett's tests, the latest of which was used to compare the control to the experimental groups. No interaction was observed between delay time and energy density regarding the degree of conversion. The cervical segment showed the highest values, while the apical showed the lowest. Microhardness values concerning the cervical segment in all groups were statistically different from that obtained for the control. A high-irradiance light-curing unit allows for a reduced irradiation exposure time with a short delay time, aimed at tooth restorations using a dual-cured resin cement. © 2014 Wiley Publishing Asia Pty Ltd.

Effects of curing protocol and storage time on the micro-hardness of resin cements used to lute fiber-reinforced resin posts

PubMed Central

RAMOS, Marcelo Barbosa; PEGORARO, Thiago Amadei; PEGORARO, Luiz Fernando; CARVALHO, Ricardo Marins

2012-01-01

Objectives To determine the micro-hardness profile of two dual cure resin cements (RelyX - U100®, 3M-ESPE and Panavia F 2.0®, Kuraray) used for cementing fiber-reinforced resin posts (Fibrekor® - Jeneric Pentron) under three different curing protocols and two water storage times. Material and methods Sixty 16mm long bovine incisor roots were endodontically treated and prepared for cementation of the Fibrekor posts. The cements were mixed as instructed, dispensed in the canal, the posts were seated and the curing performed as follows: a) no light activation; b) light-activation immediately after seating the post, and; c) light-activation delayed 5 minutes after seating the post. The teeth were stored in water and retrieved for analysis after 7 days and 3 months. The roots were longitudinally sectioned and the microhardness was determined at the cervical, middle and apical regions along the cement line. The data was analyzed by the three-way ANOVA test (curing mode, storage time and thirds) for each cement. The Tukey test was used for the post-hoc analysis. Results Light-activation resulted in a significant increase in the microhardness. This was more evident for the cervical region and for the Panavia cement. Storage in water for 3 months caused a reduction of the micro-hardness for both cements. The U100 cement showed less variation in the micro-hardness regardless of the curing protocol and storage time. Conclusions The micro-hardness of the cements was affected by the curing and storage variables and were material-dependent. PMID:23138743

Warpage of QFN Package in Post Mold Cure Process of integrated circuit packaging

NASA Astrophysics Data System (ADS)

Sriwithoon, Nattha; Ugsornrat, Kessararat; Srisuwitthanon, Warayoot; Thonglor, Panakamon

2017-09-01

This research studied about warpage of QFN package in post mold cure process of integrated circuit (IC) packages using pre-plated (PPF) leadframe. For IC package, epoxy molding compound (EMC) are molded by cross linking of compound stiffness but incomplete crosslinked network and leading the fully cured thermoset by post mold cure (PMC) process. The cure temperature of PMC can change microstructure of EMC in term of stress inside the package and effect to warpage of the package due to coefficient of thermal expansion (CTE) between EMC and leadframe. In experiment, cure temperatures were varied to check the effect of internal stress due to different cure temperature after completed post mold cure for TDFN 2×3 8L. The cure temperature were varied with 180 °C, 170 °C, 160 °C, and 150°C with cure time 4 and 6 hours, respectively. For analysis, the TDFN 2×3 8L packages were analyzed the warpage by thickness gauge and scanning acoustic microscope (SAM) after take the test samples out from the oven cure. The results confirmed that effect of different CTE between EMC and leadframe due to different cure temperature resulting to warpage of the TDFN 2×3 8L packages.

Improved survival time: what can survival cure models tell us about population-based survival improvements in late-stage colorectal, ovarian, and testicular cancer?

PubMed

Huang, Lan; Cronin, Kathleen A; Johnson, Karen A; Mariotto, Angela B; Feuer, Eric J

2008-05-15

The objective of the current study was to investigate the long-term impact of treatment advances on the survival of patients with late-stage ovarian, colorectal (American Joint Committee on Cancer stage III, men), and testicular cancers by estimating the increase in the percentage cured from their disease and the change in survival time of uncured patients. Cause-specific survival data from 1973 to 2000 were obtained from the Surveillance, Epidemiology, and End Results Program. Survival cure models were fit and were used to estimate the gain in life expectancy (GLE) attributed to an increase in the fraction of cured patients and to prolonged survival among noncured patients. Treatment improvement for ovarian cancer resulted in a total GLE of 2 years, and 80% of that GLE was because of an extension of survival time in uncured patients (from 0.9 years to 2.1 years) rather than an increased cure fraction (from 12% to 14%). In contrast, the cure rate rose from 29% to 47% for colorectal cancer, representing 82% of a 2.8-year GLE, and from 23% to 81% for testicular cancer, representing 100% of a 24-year GLE. The current results suggested that treatment benefits for testicular and colorectal cancer in men with late-stage disease primarily are the result of increases in cure fraction, whereas survival gains for ovarian cancer occur despite persisting disease. Cure models, in combination with population-level data, provide insight into how treatment advances are changing survival and ultimately impacting mortality. Survival patterns reflect the underlying biology of response to cancer treatment and suggest promising directions for future research.

40 CFR 63.3965 - How do I determine the emission capture system efficiency?

Code of Federal Regulations, 2010 CFR

2010-07-01

...; coating solvent flash-off, curing, and drying occurs within the capture system; and the removal or... spray booth and a curing oven. (b) Measuring capture efficiency. If the capture system does not meet... surface preparation activities and drying and curing time. (c) Liquid-to-uncaptured-gas protocol using a...

Evaluation of shear bond strength of orthodontic brackets using trans-illumination technique with different curing profiles of LED light-curing unit in posterior teeth.

PubMed

Heravi, Farzin; Moazzami, Saied Mostafa; Ghaffari, Negin; Jalayer, Javad; Bozorgnia, Yasaman

2013-11-21

Although using light-cured composites for bonding orthodontic brackets has become increasingly popular, curing light cannot penetrate the metallic bulk of brackets and polymerization of composites is limited to the edges. Limited access and poor direct sight may be a problem in the posterior teeth. Meanwhile, effectiveness of the trans-illumination technique is questionable due to increased bucco-lingual thickness of the posterior teeth. Light-emitting diode (LED) light-curing units cause less temperature rise and lower risk to the pulpal tissue. The purpose of this study was to evaluate the clinical effectiveness of trans-illumination technique in bonding metallic brackets to premolars, using different light intensities and curing times of an LED light-curing unit. Sixty premolars were randomly divided into six groups. Bonding of brackets was done with 40- and 80-s light curing from the buccal or lingual aspect with different intensities. Shear bond strengths of brackets were measured using a universal testing machine. Data were analyzed by one-way analysis of variance test and Duncan's post hoc test. The highest shear bond belonged to group 2 (high intensity, 40 s, buccal) and the lowest belonged to group 3 (low intensity, 40 s, lingual). Bond strength means in control groups were significantly higher than those in experimental groups. In all experimental groups except group 6 (80 s, high intensity, lingual), shear bond strength was below the clinically accepted values. In clinical limitations where light curing from the same side of the bracket is not possible, doubling the curing time and increasing the light intensity during trans-illumination are recommended for achieving acceptable bond strengths.

Fiber-optic epoxy composite cure sensor. II. Performance characteristics

NASA Astrophysics Data System (ADS)

Lam, Kai-Yuen; Afromowitz, Martin A.

1995-09-01

The performance of a fiber-optic epoxy composite cure sensor, as previously proposed, depends on the optical properties and the reaction kinetics of the epoxy. The reaction kinetics of a typical epoxy system are presented. It is a third-order autocatalytic reaction with a peak observed in each isothermal reaction-rate curve. A model is derived to describe the performance characteristics of the epoxy cure sensor. If a composite coupon is cured at an isothermal temperature, the sensor signal can be used to predict the time when the gel point occurs and to monitor the cure process. The sensor is also shown to perform well in nonstoichiometric epoxy matrices. In addition the sensor can detect the end of the cure without calibration.

Time and dose-dependence evaluation of nitroheterocyclic drugs for improving efficacy following Trypanosoma cruzi infection: A pre-clinical study.

PubMed

Mazzeti, Ana Lia; Diniz, Lívia de F; Gonçalves, Karolina R; Nascimento, Alvaro F S; Spósito, Pollyanna A F; Mosqueira, Vanessa C F; Machado-Coelho, George L L; Ribeiro, Isabela; Bahia, Maria T

2018-02-01

Benznidazole and nifurtimox-treatments regimens currently used in human are supported by very limited experimental data. This study was designed to evaluate the time and dose dependence for efficacy of the most important nitroheterocyclic drugs in use for Chagas disease. In order to evaluate time dependence, Y strain-infected mice received benznidazole for a total of 1, 3, 7, 10, 20, and 40 days. Treatment courses of 3-10-day were effective in clearing parasitaemia and suppressing mortality, but parasitological cure was not achieved. Extending the treatments to 20 or 40 days clearly improved benznidazole efficacy. The 20-day treatment induced cure in 57.1% of Y strain infections (partially drug resistant) but failed to cure Colombian strain infections (full drug resistant), while the 40-day treatment resulted in cure of 100% of Y and 50% of Colombian strain infected mice. The increased cure rates in T. cruzi infected animals that received nifurtimox for 40 days confirm the relationship between the length of treatment and efficacy. An improvement in efficacy was observed with increasing benznidazole doses; cure was verified in 28.6% (75 mg/kg), 57.1% (100 mg/kg) and 80% (300 mg/kg). Overall, these nonclinical study data provide evidence that the efficacy of benznidazole is dose and time dependent. These findings may be relevant for optimizing treatment of human Chagas disease. Copyright © 2018 Elsevier Inc. All rights reserved.

Parametric study on the compressive strength geopolymer paving block

NASA Astrophysics Data System (ADS)

Aman; Awaluddin, A.; Ahmad, A.; Olivia, M.

2018-04-01

This paper reported about the investigated of sodium hidroxida concentration, effect of ratio liquid to solid (L/S), temperature and time on the compressive strength of geopolymer paving block using fly ash and fine aggregate as base material and combination of sodium hidroxida and sodium silicate as alkaline activator and the ratio of Na2SiO3/NaOH was 2 and fly ash to aggregate of 1: 3. The experiments were conducted with variation of the sodium hidroxida concentration of (10-16 M) liquid to solid (L/S) 0.1- 0.7 ratio, curing temperature 30-100 °C and curing time (7-28 day). The main evaluation techniques in this experimental were Compressive strength, X-ray diffraction (XRD),and Scaning Electron Microscope (SEM). The result showed that the compressive strength of Geopolymer Paving block has increased with an increasing of concentration, liquid to solid ratio, curing temperature and curing time.

Lipolysis, lipid peroxidation, and color characteristics of Serrano Hams from Duroc and large white pigs during dry-curing.

PubMed

del Olmo, Ana; Calzada, Javier; Nuñez, Manuel

2013-11-01

Lipolysis, lipid peroxidation, and colorimetric characteristics of Serrano hams from Duroc and Large White pigs along a 15-mo curing period were investigated. Physicochemical parameters of both types of hams evolved similarly during curing. Twelve of 13 free fatty acids (FFAs) increased during curing, eicosatrienoic acid being the only exception. Linoleic, stearic, and arachidonic acids and the minor heptadecanoic acid reached lower concentrations, and the rest of minor FFAs higher concentrations, in Duroc hams than in Large White hams. The index measuring the early stage of lipid peroxidation declined from month 5 onwards, indicating that the phenomenon had been completed by month 5, while the index of the secondary stage of lipid peroxidation increased with curing time. Higher values were found for the 1st index in Duroc hams. Curing affected color parameters. Lightness decreased and redness increased in both types of hams, while yellowness decreased only in Duroc hams. Lower redness values were found for Duroc hams. Major differences in color parameters were found between muscles. Principal components analysis of FFAs yielded 2 main principal components. The 1st factor, correlated with all FFAs excepting eicosatrienoic acid, allowed discrimination between curing times. The 2nd factor, correlated with eicosatrienoic acid, permitted discrimination between breeds. © 2013 Institute of Food Technologists®

Ballistics ordnance gelatine - How different concentrations, temperatures and curing times affect calibration results.

PubMed

Maiden, Nicholas R; Fisk, Wesley; Wachsberger, Christian; Byard, Roger W

2015-08-01

A study was undertaken to determine whether different concentrations of ordnance gelatine, water types, temperatures and curing times would have an effect on projectile penetration of a gelatine tissue surrogate. Both Federal Bureau of Investigation (FBI) and North Atlantic Treaty Organization (NATO) specified gelatines were compared against the FBI calibration standard. 10% w/w and 20% w/w concentrations of gelatine with Bloom numbers of 250 and 285 were prepared and cured at variable temperatures (3-20°C) for 21 hours-3 weeks. Each block was shot on four occasions on the same range using steel calibre 4.5 mm BBs fired from a Daisy(®) air rifle at the required standard velocity of 180 ± 4.5 m/s, to ascertain the mean penetration depth. The results showed no significant difference in mean penetration depth using the three different water types (p > 0.05). Temperature changes and curing times did affect penetration depth. At 10°C, mean penetration depth with 20% gelatine 285 Bloom for the two water types tested was 49.7 ± 1.5 mm after 21 h curing time, whereas the same formulation at 20°C using two different water types was 79.1 ± 2.1 mm after 100 h curing time (p < 0.001). Neither of the NATO 20% concentrations of gelatine at 10°C or a 20% concentration of 285 Bloom gelatine at 10°C met the same calibration standard as the FBI recommended 10% formulation at 4°C. A 20% concentration of 285 Bloom at 20°C met the same calibration/penetration criteria as a 10% concentration of 250 Bloom at 4 °C after 100 h of curing, therefore matching the FBI calibration standard for a soft tissue simulant for wound ballistics research. These results demonstrate significant variability in simulant properties. Failure to standardise ballistic simulants may invalidate experimental results. Copyright © 2015. Published by Elsevier Ltd.

Changes in degree of conversion and microhardness of dental resin cements.

PubMed

Yan, Yong Li; Kim, Young Kyung; Kim, Kyo-Han; Kwon, Tae-Yub

2010-01-01

There are few studies available on the post-light activation or post-mix polymerization of dental resin cements as a function of time. This in vitro study evaluated the successive changes in the degree of conversion (DC) and microhardness during polymerization of six commercial resin cements (light-cured [Choice 2, RelyX Veneer], chemical-cured [Multilink, C&B Cement] and dual-cured [Calibra, RelyX ARC]) within the first 24 hours and up to seven days. Resin specimens were prepared for Fourier transform infrared (FTIR) spectroscopy and microhardness testing to determine the DC and Vickers hardness (VH), respectively. The light-cured materials or mixed pastes of the dual-cured materials were irradiated with a light-curing unit (Elipar TriLight) through a precured composite overlay for 40 seconds. The FTIR spectra and microhardness readings were taken at specified times: 1, 2, 5, 10, 15, 30 and 60 minutes; 24 hours and after two days and seven days. According to the FTIR study, most of the curing reaction of Choice 2 and RelyX Veneer occurred within 10 and 30 minutes, respectively. Multilink, C&B Cement and Calibra exhibited gradual increases in the DC up to 24 hours, with no further statistically significant increase (p > 0.05). RelyX ARC attained a DC value within five minutes, similar to that at seven days (p > 0.05). Choice 2 and RelyXARC showed gradual increases in the VH, up to 15 minutes, with no further significant change over the remaining observation time (p > 0.05). For RelyX Veneer, Multilink, C&B Cement and Calibra, there were no significant increases in the VH value after 24 hours (p > 0.05). The light-cured materials produced significantly higher DC values than the chemical-cured materials (p < 0.05). The DC values of the two dual-cured resin cements were significantly different from each other (p < 0.001). The results suggest that the significant polymerization reaction was finished within 24 hours post-mix or post-light activation for all resin cements tested.

Effect of reduced exposure times on the cytotoxicity of resin luting cements cured by high-power led

PubMed Central

ERGUN, Gulfem; EGILMEZ, Ferhan; YILMAZ, Sukran

2011-01-01

Objective Applications of resin luting agents and high-power light-emitting diodes (LED) light-curing units (LCUs) have increased considerably over the last few years. However, it is not clear whether the effect of reduced exposure time on cytotoxicity of such products have adequate biocompatibility to meet clinical success. This study aimed at assessing the effect of reduced curing time of five resin luting cements (RLCs) polymerized by high-power LED curing unit on the viability of a cell of L-929 fibroblast cells. Material and Methods Disc-shaped samples were prepared in polytetrafluoroethylene moulds with cylindrical cavities. The samples were irradiated from the top through the ceramic discs and acetate strips using LED LCU for 20 s (50% of the manufacturer's recommended exposure time) and 40 s (100% exposure time). After curing, the samples were transferred into a culture medium for 24 h. The eluates were obtained and pipetted onto L-929 fibroblast cultures (3x104 per well) and incubated for evaluating after 24 h. Measurements were performed by dimethylthiazol diphenyltetrazolium assay. Statistical significance was determined by two-way ANOVA and two independent samples were compared by t-test. Results Results showed that eluates of most of the materials polymerized for 20 s (except Rely X Unicem and Illusion) reduced to a higher extent cell viability compared to samples of the same materials polymerized for 40 s. Illusion exhibited the least cytotoxicity for 20 s exposure time compared to the control (culture without samples) followed by Rely X Unicem and Rely X ARC (90.81%, 88.90%, and 83.11%, respectively). For Rely X ARC, Duolink and Lute-It 40 s exposure time was better (t=-1.262 p=0,276; t=-9.399 p=0.001; and t=-20.418 p<0.001, respectively). Conclusion The results of this study suggest that reduction of curing time significantly enhances the cytotoxicity of the studied resin cement materials, therefore compromising their clinical performance. PMID:21625748

2.45 GHz Microwave Processing and Its Influence on Glass Fiber Reinforced Plastics.

PubMed

Teufl, Daniel; Zaremba, Swen

2018-05-18

During the production of fiber-reinforced composite materials, liquid resin is introduced into the fiber material and cured, i.e., hardened. An elevated temperature is needed for this curing. Microwave curing of composites has been investigated for some time, but it has mostly been done using small domestic or laboratory equipment. However, no investigation has been carried out using an industrial-sized chamber-microwave for glass fiber-reinforced plastic (GFRP). Here, we show that microwave curing produces laminates of the same quality as oven-cured ones. The study shows that, if the process is done right, GFRP samples can be produced with an industrial scale microwave. Even if not fully cured, microwave samples show a glass transition temperature measured with DMA ( T g-DMA ) that is comparable to the T g-DMA according to the proposed cure cycle on the data sheet. Specific microwave-cured configurations show better inter-laminar shear strength than oven specimens. The results show that microwave-based heat introduction can be a beneficial curing method for GFRP laminates. A microwave-optimized process is faster and leads to better mechanical properties.

Process Modelling of Curing Process-Induced Internal Stress and Deformation of Composite Laminate Structure with Elastic and Viscoelastic Models

NASA Astrophysics Data System (ADS)

Li, Dongna; Li, Xudong; Dai, Jianfeng

2018-06-01

In this paper, two kinds of transient models, the viscoelastic model and the linear elastic model, are established to analyze the curing deformation of the thermosetting resin composites, and are calculated by COMSOL Multiphysics software. The two models consider the complicated coupling between physical and chemical changes during curing process of the composites and the time-variant characteristic of material performance parameters. Subsequently, the two proposed models are implemented respectively in a three-dimensional composite laminate structure, and a simple and convenient method of local coordinate system is used to calculate the development of residual stresses, curing shrinkage and curing deformation for the composite laminate. Researches show that the temperature, degree of curing (DOC) and residual stresses during curing process are consistent with the study in literature, so the curing shrinkage and curing deformation obtained on these basis have a certain referential value. Compared the differences between the two numerical results, it indicates that the residual stress and deformation calculated by the viscoelastic model are more close to the reference value than the linear elastic model.

Effect of commercially available egg cures on the survival of juvenile salmonids

USGS Publications Warehouse

Clements, S.; Chitwood, R.; Schreck, C.B.

2011-01-01

There is some concern that incidental consumption of eggs cured with commercially available cures for the purpose of sport fishing causes mortality in juvenile salmon. We evaluated this by feeding juvenile spring Chinook (Oncorhynchus tshawytscha) and steelhead (O. mykiss) with eggs cured with one of five commercially available cures. We observed significant levels of mortality in both pre-smolts and smolts. Depending on the experiment, 2, 3, or 4 of the cures were associated with mortality. Mortality tended to be higher in the smolts than in the parr, but there was no clear species effect. The majority of mortality occurred within the first 10 d of feeding. Removal of sodium sulfite from the cure significantly reduced the level of mortality. Soaking the eggs prior to feeding did not reduce mortality. We observed a clear relationship between the amount of cured egg consumed each day and the survival time. We conclude that consumption of eggs cured with sodium sulfite has the potential to cause mortality in juvenile steelhead and Chinook salmon in the wild.

2.45 GHz Microwave Processing and Its Influence on Glass Fiber Reinforced Plastics

PubMed Central

Zaremba, Swen

2018-01-01

During the production of fiber-reinforced composite materials, liquid resin is introduced into the fiber material and cured, i.e., hardened. An elevated temperature is needed for this curing. Microwave curing of composites has been investigated for some time, but it has mostly been done using small domestic or laboratory equipment. However, no investigation has been carried out using an industrial-sized chamber-microwave for glass fiber-reinforced plastic (GFRP). Here, we show that microwave curing produces laminates of the same quality as oven-cured ones. The study shows that, if the process is done right, GFRP samples can be produced with an industrial scale microwave. Even if not fully cured, microwave samples show a glass transition temperature measured with DMA (Tg-DMA) that is comparable to the Tg-DMA according to the proposed cure cycle on the data sheet. Specific microwave-cured configurations show better inter-laminar shear strength than oven specimens. The results show that microwave-based heat introduction can be a beneficial curing method for GFRP laminates. A microwave-optimized process is faster and leads to better mechanical properties. PMID:29783684

Development of a Fully Automated Guided Wave System for In-Process Cure Monitoring of CFRP Composite Laminates

NASA Technical Reports Server (NTRS)

Hudson, Tyler B.; Hou, Tan-Hung; Grimsley, Brian W.; Yaun, Fuh-Gwo

2016-01-01

A guided wave-based in-process cure monitoring technique for carbon fiber reinforced polymer (CFRP) composites was investigated at NASA Langley Research Center. A key cure transition point (vitrification) was identified and the degree of cure was monitored using metrics such as amplitude and time of arrival (TOA) of guided waves. Using an automated system preliminarily developed in this work, high-temperature piezoelectric transducers were utilized to interrogate a twenty-four ply unidirectional composite panel fabricated from Hexcel (Registered Trademark) IM7/8552 prepreg during cure. It was shown that the amplitude of the guided wave increased sharply around vitrification and the TOA curve possessed an inverse relationship with degree of cure. The work is a first step in demonstrating the feasibility of transitioning the technique to perform in-process cure monitoring in an autoclave, defect detection during cure, and ultimately a closed-loop process control to maximize composite part quality and consistency.

Concordance measure and discriminatory accuracy in transformation cure models.

PubMed

Zhang, Yilong; Shao, Yongzhao

2018-01-01

Many populations of early-stage cancer patients have non-negligible latent cure fractions that can be modeled using transformation cure models. However, there is a lack of statistical metrics to evaluate prognostic utility of biomarkers in this context due to the challenges associated with unknown cure status and heavy censorship. In this article, we develop general concordance measures as evaluation metrics for the discriminatory accuracy of transformation cure models including the so-called promotion time cure models and mixture cure models. We introduce explicit formulas for the consistent estimates of the concordance measures, and show that their asymptotically normal distributions do not depend on the unknown censoring distribution. The estimates work for both parametric and semiparametric transformation models as well as transformation cure models. Numerical feasibility of the estimates and their robustness to the censoring distributions are illustrated via simulation studies and demonstrated using a melanoma data set. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

INTEGRATION OF COST MODELS AND PROCESS SIMULATION TOOLS FOR OPTIMUM COMPOSITE MANUFACTURING PROCESS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pack, Seongchan; Wilson, Daniel; Aitharaju, Venkat

Manufacturing cost of resin transfer molded composite parts is significantly influenced by the cycle time, which is strongly related to the time for both filling and curing of the resin in the mold. The time for filling can be optimized by various injection strategies, and by suitably reducing the length of the resin flow distance during the injection. The curing time can be reduced by the usage of faster curing resins, but it requires a high pressure injection equipment, which is capital intensive. Predictive manufacturing simulation tools that are being developed recently for composite materials are able to provide variousmore » scenarios of processing conditions virtually well in advance of manufacturing the parts. In the present study, we integrate the cost models with process simulation tools to study the influence of various parameters such as injection strategies, injection pressure, compression control to minimize high pressure injection, resin curing rate, and demold time on the manufacturing cost as affected by the annual part volume. A representative automotive component was selected for the study and the results are presented in this paper« less

40 CFR 63.4165 - How do I determine the emission capture system efficiency?

Code of Federal Regulations, 2010 CFR

2010-07-01

... system; coating solvent flash-off and coating, curing, and drying occurs within the capture system and... when being moved between a spray booth and a curing oven. (b) If the capture system does not meet both... surface preparation activities and drying or curing time. (c) Liquid-to-uncaptured-gas protocol using a...

Defining the Chance of Statistical Cure Among Patients with Extrahepatic Biliary Tract Cancer.

PubMed

Spolverato, Gaya; Bagante, Fabio; Ethun, Cecilia G; Poultsides, George; Tran, Thuy; Idrees, Kamran; Isom, Chelsea A; Fields, Ryan C; Krasnick, Bradley; Winslow, Emily; Cho, Clifford; Martin, Robert C G; Scoggins, Charles R; Shen, Perry; Mogal, Harveshp D; Schmidt, Carl; Beal, Eliza; Hatzaras, Ioannis; Shenoy, Rivfka; Maithel, Shishir K; Pawlik, Timothy M

2017-01-01

While surgery offers the best curative-intent treatment, many patients with biliary tract malignancies have poor long-term outcomes. We sought to apply a non-mixture cure model to calculate the cure fraction and the time to cure after surgery of patients with peri-hilar cholangiocarcinoma (PHCC) or gallbladder cancer (GBC). Using the Extrahepatic Biliary Malignancy Consortium, 576 patients who underwent curative-intent surgery for gallbladder carcinoma or peri-hilar cholangiocarcinoma between 1998 and 2014 at 10 major hepatobiliary institutions were identified and included in the analysis. A non-mixture cure model was adopted to compare mortality after surgery to the mortality expected for the general population matched by sex and age. The median and 5-year overall survival (OS) were 1.9 years (IQR, 0.9-4.9) and 23.9 % (95 % CI, 19.6-28.6). Among all patients with PHCC or GBC, the probability of being cured after surgery was 14.5 % (95 % CI, 8.7-23.2); the time to cure was 9.7 years and the median survival of uncured patients was 1.8 years. Determinants of cure probabilities included lymph node metastasis and CA 19.9 level (p ≤ 0.05). The cure fraction for patients with a CA 19.9 < 50 U/ml and no lymph nodes metastases were 39.0 % versus only 5.1 % among patients with a CA 19.9 ≥ 50 who also had lymph node metastasis. Examining an "all comer" cohort, <15 % of patients with PHCC or GBC could be considered cured after surgery. Factors such CA 19.9 level and lymph node metastasis independently predicted long-term outcome. Estimating the odds of statistical cure following surgery for biliary tract cancer can assist in decision-making as well as inform discussions around survivorship.

Defining the Chance of Statistical Cure Among Patients with Extrahepatic Biliary Tract Cancer

PubMed Central

Spolverato, Gaya; Bagante, Fabio; Ethun, Cecilia G.; Poultsides, George; Tran, Thuy; Idrees, Kamran; Isom, Chelsea A.; Fields, Ryan C.; Krasnick, Bradley; Winslow, Emily; Cho, Clifford; Martin, Robert C. G.; Scoggins, Charles R.; Shen, Perry; Mogal, Harveshp D.; Schmidt, Carl; Beal, Eliza; Hatzaras, Ioannis; Shenoy, Rivfka; Maithel, Shishir K.; Pawlik, Timothy M.

2017-01-01

Background While surgery offers the best curative-intent treatment, many patients with biliary tract malignancies have poor long-term outcomes. We sought to apply a non-mixture cure model to calculate the cure fraction and the time to cure after surgery of patients with peri-hilar cholangiocarcinoma (PHCC) or gallbladder cancer (GBC). Methods Using the Extrahepatic Biliary Malignancy Consortium, 576 patients who underwent curative-intent surgery for gallbladder carcinoma or peri-hilar cholangiocarcinoma between 1998 and 2014 at 10 major hepatobiliary institutions were identified and included in the analysis. A non-mixture cure model was adopted to compare mortality after surgery to the mortality expected for the general population matched by sex and age. Results The median and 5-year overall survival (OS) were 1.9 years (IQR, 0.9–4.9) and 23.9 % (95 % CI, 19.6–28.6). Among all patients with PHCC or GBC, the probability of being cured after surgery was 14.5 % (95 % CI, 8.7–23.2); the time to cure was 9.7 years and the median survival of uncured patients was 1.8 years. Determinants of cure probabilities included lymph node metastasis and CA 19.9 level (p ≤ 0.05). The cure fraction for patients with a CA 19.9 < 50 U/ml and no lymph nodes metastases were 39.0 % versus only 5.1 % among patients with a CA 19.9 ≥ 50 who also had lymph node metastasis. Conclusions Examining an “all comer” cohort, <15 % of patients with PHCC or GBC could be considered cured after surgery. Factors such CA 19.9 level and lymph node metastasis independently predicted long-term outcome. Estimating the odds of statistical cure following surgery for biliary tract cancer can assist in decision-making as well as inform discussions around survivorship. PMID:27549595

Influence of etching time and bonding strategies on the microshear bond strength of self- and light-cured pit-and-fissure sealants.

PubMed

Souza-Junior, Eduardo José; Borges, Boniek Castillo Dutra; Montes, Marcos Antônio Japiassú Resende; Alonso, Roberta Caroline Bruschi; Ambrosano, Glaucia Maria Bovi; Sinhoreti, Mário Alexandre Coelho

2012-01-01

This study evaluated the impact of extended etching and bonding strategies on the microshear bond strength of three sealant materials. Two pit-and-fissure sealants [FluroShield, Dentsply (light-cured) and AlphaSeal, DFL (self-cured)] and one light-cured flowable composite resin (Permaflo, Ultradent) were evaluated according to different enamel etching times (15 s or 30 s) and bonding procedures (no adhesive application, application of primer/hydrophobic resin or hydrophobic resin only). Intact enamel blocks were obtained from bovine teeth and sealed via the tested protocols. After 24 h, the microshear bond strength test was performed in a universal testing machine at a crosshead speed of 0.5 mm/min. Failure modes were classified by stereomicroscopy. Data were submitted to a three-way ANOVA and to Tukey's test (α=0.05). There was no statistically significant difference (p>0.05) among the materials. Permaflo showed higher bond strength when etched for 30 s alone. Enamel overetching decreased the bond strength of the light-cured sealant. Primer/bond previous treatment improved bond performance for AlphaSeal. In conclusion, from the tested conditions, all sealant materials presented similar bond strength values in relation to bonding protocol and etching time. The flowable composite can be used as a pit-and-fissure sealant. The use of a three-step adhesive system was essential for the self-cured sealant application.

Fitting Cure Rate Model to Breast Cancer Data of Cancer Research Center.

PubMed

Baghestani, Ahmad Reza; Zayeri, Farid; Akbari, Mohammad Esmaeil; Shojaee, Leyla; Khadembashi, Naghmeh; Shahmirzalou, Parviz

2015-01-01

The Cox PH model is one of the most significant statistical models in studying survival of patients. But, in the case of patients with long-term survival, it may not be the most appropriate. In such cases, a cure rate model seems more suitable. The purpose of this study was to determine clinical factors associated with cure rate of patients with breast cancer. In order to find factors affecting cure rate (response), a non-mixed cure rate model with negative binomial distribution for latent variable was used. Variables selected were recurrence cancer, status for HER2, estrogen receptor (ER) and progesterone receptor (PR), size of tumor, grade of cancer, stage of cancer, type of surgery, age at the diagnosis time and number of removed positive lymph nodes. All analyses were performed using PROC MCMC processes in the SAS 9.2 program. The mean (SD) age of patients was equal to 48.9 (11.1) months. For these patients, 1, 5 and 10-year survival rates were 95, 79 and 50 percent respectively. All of the mentioned variables were effective in cure fraction. Kaplan-Meier curve showed cure model's use competence. Unlike other variables, existence of ER and PR positivity will increase probability of cure in patients. In the present study, Weibull distribution was used for the purpose of analysing survival times. Model fitness with other distributions such as log-N and log-logistic and other distributions for latent variable is recommended.

Long term isothermal aging and thermal analysis of N-CYCAP polyimides

NASA Technical Reports Server (NTRS)

Sutter, James K.; Waters, John F.; Schverman, Marla A.

1991-01-01

The N-CYCAP polyimides utilize a (2,2) paracyclophane endcap that polymerizes and does not generate volatile gases during the cure process. These polyimides have both high glass temperatures (390 C) and an onset of decomposition in air of 560 C. Thermal oxidative stability (TOS) weight loss studies show that replacing 25 percent by weight of the paraphenylene diamine in the polymer backbone with metaphenylene diamine improves the weight loss characteristics. N-CYCAP neat resin samples performed better than PMR-II-50 when exposed at 343 and 371 C in air for up to 1000 hours. Preliminary composite studies show that both PMR-II-50 and N-CYCAP have better thermal stability when fabricated on T-40R. Higher isothermal aging temperatures of longer aging times are needed to determine the differences in TOS between composite samples of PMR-II-50 and N-CYCAP polyimides.

Modified Unzipping Technique to Prepare Graphene Nano-Sheets

NASA Astrophysics Data System (ADS)

Al-Tamimi, B. H.; Farid, S. B. H.; Chyad, F. A.

2018-05-01

Graphene nano-sheets have been prepared via unzipping approach of multiwall carbon nanotubes (MWCNTs). The method includes two chemical-steps, in which a multi-parameter oxidation step is performed to achieve unzipping the carbon nanotubes. Then, a reduction step is carried out to achieve the final graphene nano-sheets. In the oxidation step, the oxidant material was minimized and balanced with longer curing time. This modification is made in order to reduce the oxygen-functional groups at the ends of graphene basal planes, which reduce its electrical conductivity. In addition, a similar adjustment is achieved in the reduction step, i.e. the consumed chemicals is reduced which make the overall process more economic and eco-friendly. The prepared nano-sheets were characterized by atomic force microscopy, scanning electron microscopy, and Raman spectroscopy. The average thickness of the prepared graphene was about 5.23 nm.

Clearance of Hepatitis C Virus Prior to Lung Transplantation: A Case Report.

PubMed

Shafii, A E; Harris, D D; Baz, M

2017-09-01

Hepatitis C virus (HCV) continues to be considered a relative contraindication to lung transplantation due to concerns of progression of liver disease with the introduction of immunosuppression. Since the recent introduction of effective antiviral therapy for HCV, new approaches in the management of the HCV-positive recipient are being utilized in liver transplantation to clear HCV pre- and post-transplant. Herein, we report use of ledipasvir/sofosbuvir for HCV clearance prior to lung transplantation in a patient with usual interstitial pneumonia. Listing for transplant was delayed until completion of HCV treatment, and he subsequently required extracorporeal membrane oxygenation as a bridge to transplantation due to progressive hypoxia. With antiviral cure rates exceeding 90%, HCV should no longer be considered a relative contraindication to lung transplant, and timing of antiviral treatment should consider the progressive nature of the recipient's lung disease. Copyright © 2017 Elsevier Inc. All rights reserved.

Depth of cure, flexural properties and volumetric shrinkage of low and high viscosity bulk-fill giomers and resin composites.

PubMed

Tsujimoto, Akimasa; Barkmeier, Wayne W; Takamizawa, Toshiki; Latta, Mark A; Miyazaki, Masashi

2017-03-31

The purpose of this study was to investigate the depth of cure, flexural properties and volumetric shrinkage of low and high viscosity bulk-fill giomers and resin composites. Depth of cure and flexural properties were determined according to ISO 4049, and volumetric shrinkage was measured using a dilatometer. The depths of cure of giomers were significantly lower than those of resin composites, regardless of photo polymerization times. No difference in flexural strength and modulus was found among either high or low viscosity bulk fill materials. Volumetric shrinkage of low and high viscosity bulk-fill resin composites was significantly less than low and high viscosity giomers. Depth of cure of both low and high viscosity bulk-fill materials is time dependent. Flexural strength and modulus of high viscosity or low viscosity bulk-fill giomer or resin composite materials are not different for their respective category. Resin composites exhibited less polymerization shrinkage than giomers.

Outgassing of Out-of-Autoclave Composite Primary Structures for Small Satellites

NASA Astrophysics Data System (ADS)

Komus, Alastair

Out-of-autoclave vacuum-bagged-only (VBO) processing is capable of producing lower cost composite primary structures for small satellites than autoclave processing. However, the outgassing performance of VBO structures in a vacuum environment has not been examined. Panels were manufactured from CYCOM 5320-1 and TC275-1 carbon fiber/epoxy prepreg using VBO processing. The humidity level, pre-cure dwell time, and cure cycle parameters were varied during manufacturing. The degree of cure and glass transition temperature were shown to increase with increasing oven temperature. Processing humidity levels and the length of pre-cure dwell times had no discernable effect on the total mass loss (TML) and collected volatile condensable material (CVCM) that were outgassed under vacuum. Instead the TML was controlled by moisture saturation after manufacturing. Fourier transform infrared spectroscopy showed that epoxy oligomers were the primary CVCM. The study showed the VBO laminates had outgassing values that were comparable to the autoclave-cured laminates.

An infiltration/cure model for manufacture of fabric composites by the resin infusion process

NASA Technical Reports Server (NTRS)

Weideman, Mark H.; Loos, Alfred C.; Dexter, H. Benson; Hasko, Gregory H.

1992-01-01

A 1-D infiltration/cure model was developed to simulate fabrication of advanced textile composites by the resin film infusion process. The simulation model relates the applied temperature and pressure processing cycles, along with the experimentally measured compaction and permeability characteristics of the fabric preforms, to the temperature distribution, the resin degree of cure and viscosity, and the infiltration flow front position as a function of time. The model also predicts the final panel thickness, fiber volume fraction, and resin mass for full saturation as a function of compaction pressure. Composite panels were fabricated using the RTM (Resin Transfer Molding) film infusion technique from knitted, knitted/stitched, and 2-D woven carbon preforms and Hercules 3501-6 resin. Fabric composites were fabricated at different compaction pressures and temperature cycles to determine the effects of the processing on the properties. The composites were C-scanned and micrographed to determine the quality of each panel. Advanced cure cycles, developed from the RTM simulation model, were used to reduce the total cure cycle times by a factor of 3 and the total infiltration times by a factor of 2.

New curing system of urea-formaldehyde resind with polyhydrazides. I. Curing with dihydrazie compounds

Treesearch

Bunichiro Tomita; Hideaki Osawa; Chung-Yun Hse; George E. Myers

1989-01-01

A nonconventional curing system was developed using a simple mixing of urea-formaldehyde (UF) resins with polyfunctional hydrazide compounds under neutral contition. Several kinds of low molecular-weight dihydrazide compounds were investigated as hardners of the UF resins. Results were as follows: 1) As the minimum gelation times were observed in the range of molar...

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.

[Physical and mechanical properties of the thermosetting resin for crown and bridge cured by micro-wave heating].

PubMed

Kaneko, K

1989-09-01

A heating method using micro-waves was utilized to obtain strong thermosetting resin for crown and bridge. The physical and mechanical properties of the thermosetting resin were examined. The resin was cured in a shorter time by the micro-waves heating method than by the conventional heat curing method and the working time was reduced markedly. The base resins of the thermosetting resin for crown and bridge for the micro-waves heating method were 2 PA and diluent 3 G. A compounding volume of 30 wt% for diluent 3 G was considered good the results of compressive strength, bending strength and diametral tensile strength. Grams of 200-230 of the filler compounded to the base resins of 2 PA-3 G system provided optimal compressive strength, bending strength and diametral tensile strength. A filler gram of 230 provided optimal hardness and curing shrinkage rate, the coefficient of thermal expansion became smaller with the increase of the compounding volume of the filler. The trial thermosetting resin for crown and bridge formed by the micro-waves heating method was not inferior to the conventional resin by the heat curing method or the light curing method.

Role of age and tumour stage in the temporal pattern of 'cure' from stomach cancer: a population-based study in Osaka, Japan.

PubMed

Ito, Yuri; Nakayama, Tomio; Tsukuma, Hideaki; Miyashiro, Isao; Ioka, Akiko; Sugimoto, Tomoyuki; Rachet, Bernard

2012-04-01

To evaluate progress in stomach cancer care in Japan since 1975. Population-based study of data extracted from the Osaka Cancer Registry. Population-based cancer registry in the area of Osaka Prefecture. All 66,032 cases diagnosed with a stomach cancer in Osaka Prefecture, Japan between 1975 and 2000 and registered in the Osaka Cancer Registry. 'Cure' fraction and median survival time for 'uncured' patients were estimated with multivariable mixture 'cure' model. The role played by age and stage at diagnosis on the changes in 'cure' parameters between 1975 and 2000 was evaluated. Missing stage was handled by multiple imputation approach. More than 50% of the patients diagnosed with a stomach cancer in 1996-2000 were estimated 'cured' from their cancer, corresponding to a 20% increase since 1975-1980. Median survival time for 'uncured' patients however remained unchanged at about 8 months. 'Cure' fraction was over 85% for localised tumours and 30% for regional tumours, but stayed as low as 2.5% for distant metastatic cancers. Improvement was underestimated by about 10% because of ageing of cancer patients. Changes in stage distribution explained up to 40% of the increase in 'cure' fraction among men and up to 13% in women. Overdiagnosis was unlikely to play any role in these patterns. 'Cure' fraction from stomach cancer dramatically increased in Osaka, Japan since 1975, partly because of earlier stage at diagnosis, but mostly due to improvement in treatment of stomach cancer patients. This study, based on a leading country in term of stomach cancer management, provides insightful results for other countries in which 'cure' fraction is usually much lower. Copyright © 2012 Elsevier Ltd. All rights reserved.

Relapse after Oral Terbinafine Therapy in Dermatophytosis: A Clinical and Mycological Study.

PubMed

Majid, Imran; Sheikh, Gousia; Kanth, Farhath; Hakak, Rubeena

2016-01-01

The incidence of recurrent tinea infections after oral terbinafine therapy is on the rise. This study aims to identify the appearance of incomplete cure and relapse after 2-week oral terbinafine therapy in tinea corporis and/or tinea cruris. A total of 100 consecutive patients clinically and mycologically diagnosed to have tinea corporis and/or tinea cruris were included in the study. The enrolled patients were administered oral terbinafine 250 mg once daily for 2 weeks. All clinically cured patients were then followed up for 12 weeks to look for any relapse/cure. The common dermatophytes grown on culture were Trichophyton rubrum and Trichophyton tonsurans in 55% and 20% patients, respectively. At the end of 2-week oral terbinafine therapy, 30% patients showed a persistent disease on clinical examination while 35% patients showed a persistent positive fungal culture (persisters) at this time. These culture positive patients included all the clinically positive cases. Rest of the patients (65/100) demonstrated both clinical and mycological cure at this time (cured). Over the 12-week follow-up, clinical relapse was seen in 22 more patients (relapse) among those who had shown clinical and mycological cure at the end of terbinafine therapy. Thus, only 43% patients could achieve a long-term clinical and mycological cure after 2 weeks of oral terbinafine treatment. Majority of the relapses (16/22) were seen after 8 weeks of completion of treatment. There was no statistically significant difference in the body surface area involvement or the causative organism involved between the cured, persister, or relapse groups. Incomplete mycological cure as well as relapse is very common after standard (2-week) terbinafine therapy in our patients of tinea cruris/corporis.

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.

Human lactobacilli as supplementation of clindamycin to patients with bacterial vaginosis reduce the recurrence rate; a 6-month, double-blind, randomized, placebo-controlled study

PubMed Central

2008-01-01

Background The primary objective of this study was to investigate if supplementary lactobacilli treatment could improve the initial cure rate after vaginal clindamycin therapy, and secondly, if lactobacilli as repeated adjunct treatment during 3 menstrual cycles could lengthen the time to relapse after initial cure. Methods Women (n = 100) with bacterial vaginosis diagnosed by Amsel criteria were after informed consent offered vaginal clindamycin therapy followed by vaginal gelatine capsules containing either 109 freeze-dried lactobacilli or identical placebo capsules for 10 days during 3 menstrual cycles in a double-blind, randomized, placebo-controlled trial. Results The initial intent to treat (ITT) analysis for the one-month cure rate was 64% in the lactobacilli group and 78% in the placebo group (p > 0.05). However, any patient with missing or unclassified smears at the initial visit who continued the study and whose next smear indicated a cure was included in the cured group; the study also excluded two of the patients in the lactobacilli group who reported that they did not take any vaginal capsules. With consideration to these population changes, the initial cure rate would be 77% in the lactobacilli group. The 76 cured women were followed for 6 menstrual cycles or until relapse within that time span. At the end of the study, 64.9% (24/37) of the lactobacilli treated women were still BV-free compared to 46.2% (18/39) of the placebo treated women. Comparison of the two groups regarding "Time from cure to relapse" was statistically significant (p = 0.027) in favour of the lactobacilli treatment. Adjuvant therapy with lactobacilli contributed significantly to avoidance of relapse with a proportional Hazard Risk ratio (HR) of 0.73 (0.54–0.98) (p < 0.05) Conclusion The study shows that supplementary treatment combining two different strains of probiotic lactobacilli does not improve the efficacy of BV therapy during the first month of treatment, but for women initially cured, adjunct treatment of lactobacilli during 3 menstrual cycles lengthens the time to relapse significantly in that more women remained BV free at the end of the 6-month follow up. Trial registration number ISRCTN62879834 PMID:18197974

Impact of hepatitis C oral therapy in portal hypertension.

PubMed

Libânio, Diogo; Marinho, Rui Tato

2017-07-14

Chronic hepatitis C is a leading cause of morbidity and mortality, mainly related to fibrosis/cirrhosis and portal hypertension. Direct antiviral agents are highly effective and safe and can now cure > 90% of the patients. Sustained viral response (SVR) after interferon-based regimens has been associated with improvement in liver function, fibrosis and portal hypertension in a significant proportion of patients, although a point of no return seems to exist from which viral elimination is no longer capable of preventing portal hypertension progression and liver decompensation. Indeed, although SVR is associated with improvement of hepatic venous pressure gradients and therefore a decreased risk of de novo esophageal varices, several studies show that viral clearance does not eliminate the risk of variceal progression, liver decompensation and death in patients with pre-established portal hypertension. Although evidence about the effects of direct antiviral agents (DAAs) on clinically significant outcomes is still scarce and with short follow-up, DAAs can decrease the burden of the disease if patients are timely treated before significant fibrosis and portal hypertension develops. Studies with longer follow-up are waited to establish the real magnitude of hepatitis C treatment on portal hypertension. Future studies should also focus on predictors of portal hypertension resolution since it can influence management and avoid unnecessary monitoring.

Patients cured of acromegaly do not experience improvement of their skull deformities.

PubMed

Rick, Jonathan W; Jahangiri, Arman; Flanigan, Patrick M; Aghi, Manish K

2017-04-01

Acromegaly is a rare disease that is associated with many co-morbidities. This condition also causes progressive deformity of the skull which includes frontal bossing and cranial thickening. Surgical and/or medical management can cure this condition in many patients, but it is not understood if patients cured of acromegaly experience regression of their skull deformities. We performed a retrospective analysis on patients treated at our dedicated pituitary center from 2009 to 2014. We looked at all MRI images taken during the treatment of these patients and recorded measurements on eight skull dimensions. We then analyzed these measurements for changes over time. 29 patients underwent curative treatment for acromegaly within our timeframe. The mean age for this population was 45.0 years old (range 19-70) and 55.2 % (n = 16) were female. All of these patients were treated with a transsphenoidal resection for a somatotropic pituitary adenoma. 9 (31.1%) of these patients required further medical therapy to be cured. We found statically significant variation in the coronal width of the sella turcica after therapy, which is likely attributable to changes from transsphenoidal surgery. None of the other dimensions had significant variation over time after cure. Patients cured of acromegaly should not expect natural regression of their skull deformities. Our study suggests that both frontal bossing and cranial thickening do not return to normal after cure.

Curing mode affects bond strength of adhesively luted composite CAD/CAM restorations to dentin.

PubMed

Lührs, Anne-Katrin; Pongprueksa, Pong; De Munck, Jan; Geurtsen, Werner; Van Meerbeek, Bart

2014-03-01

To determine the effect of curing mode and restoration-surface pre-treatment on the micro-tensile bond strength (μTBS) to dentin. Sandblasted CAD/CAM composite blocks (LAVA Ultimate, 3M ESPE) were cemented to bur-cut dentin using either the etch & rinse composite cement Nexus 3 ('NX3', Kerr) with Optibond XTR ('XTR', Kerr), or the self-etch composite cement RelyX Ultimate ('RXU', 3M ESPE) with Scotchbond Universal ('SBU', 3M ESPE). All experimental groups included different 'curing modes' (light-curing of adhesive and cement ('LL'), light-curing of adhesive and auto-cure of cement ('LA'), co-cure of adhesive through light-curing of cement ('AL'), or complete auto-cure ('AA')) and different 'restoration-surface pre-treatments' of the composite block (NX3: either a silane primer (Kerr), or the XTR adhesive; RXU: either silane primer (RelyX Ceramic Primer, 3M ESPE) and SBU, or solely SBU). After water-storage (7 days, 37°C), the μTBS was measured. Additionally, the degree of conversion (DC) of both cements was measured after 10min and after 1 week, either auto-cured (21°C/37°C) or light-cured (directly/through 3-mm CAD/CAM composite). The linear mixed-effects model (α=0.05) revealed a significant influence of the factors 'curing mode' and 'composite cement', and a less significant effect of the factor 'restoration-surface pre-treatment'. Light-curing 'LL' revealed the highest μTBS, which decreased significantly for all other curing modes. For curing modes 'AA' and 'AL', the lowest μTBS and a high percentage of pre-testing failures were reported. Overall, DC increased with light-curing and incubation time. The curing mode is decisive for the bonding effectiveness of adhesively luted composite CAD/CAM restorations to dentin. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

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. © 2016 UICC.

Highlights from the HIV Cure and Reservoir Symposium, 11-12 September 2017, Ghent, Belgium.

PubMed

Kint, Sam; Van Hecke, Clarissa; Cole, Basiel; Vandekerckhove, Linos; Sips, Magdalena

2018-01-01

For the second time, the HIV Cure Research Center (HCRC) at Ghent University organised the HIV Cure and Reservoir Symposium, in Ghent, Belgium, where in this two-day conference, virologists, molecular biologists, immunologists and clinicians presented the most recent achievements in the field of HIV cure, including data on therapeutic vaccines, HIV remission strategies such as 'shock and kill' or 'block and lock', benefits of early ART and potential of haematopoietic stem cell transplant in achieving cure. Furthermore, methods to characterise and quantify the HIV reservoir were discussed along with HIV reservoir characterisation in different body parts, including the central nervous system. An HIV activist and representative of a patients' agency also presented the patients' perspective on HIV cure. This report is a summary of all topics discussed during this symposium.

Is aspiration and sclerotherapy treatment for hydroceles in the aging male an evidence-based treatment?

PubMed

Taylor, W St J; Cobley, J; Mahmalji, W

2018-01-16

Symptomatic hydroceles are commonly treated with surgical repair. They are associated with sexual dysfunction in the aging male. Patients who are not fit for surgery often undergo aspiration and sclerotherapy of the hydrocele. There is a range of sclerosing agents used in the literature. I performed a literature search to assess whether one sclerosant was better than the others. STDS is the sclerosing agent with the best cure rate after a single injection and low side effect rates. The cure rates of sodium tetradecyl sulphate (STDS) after a single aspiration and injection were 76%. After multiple treatments 94% achieved a cure. Patient satisfaction rates at mean 40 months were 95%. Complication rates were generally low and much lower than surgical repair. Aspiration and sclerotherapy have a role in treating symptomatic hydroceles. This literature review shows that this is over and above its current use in the UK, where it is used for patients unfit for general anaesthetic. If the patients are carefully selected for this procedure, they can have a good outcome and avoid the higher complication rate and longer recovery rates of surgical repair. Patients should be counselled about aspiration and sclerotherapy as part of the informed consent process.

Fiber Reinforced Polyester Resins Polymerized by Microwave Source

NASA Astrophysics Data System (ADS)

Visco, A. M.; Calabrese, L.; Cianciafara, P.; Bonaccorsi, L.; Proverbio, E.

2007-12-01

Polyester resin based composite materials are widely used in the manufacture of fiberglass boats. Production time of fiberglass laminate components could be strongly reduced by using an intense energy source as well as microwaves. In this work a polyester resin was used with 2% by weight of catalyst and reinforced with chopped or woven glass fabric. Pure resin and composite samples were cured by microwaves exposition for different radiation times. A three point bending test was performed on all the cured samples by using an universal testing machine and the resulting fracture surfaces were observed by means of scanning electron microscopy (SEM). The results of mechanical and microscopy analyses evidenced that microwave activation lowers curing time of the composite while good mechanical properties were retained. Microwaves exposition time is crucial for mechanical performance of the composite. It was evidenced that short exposition times suffice for resin activation while long exposure times cause fast cross linking and premature matrix fracture. Furthermore high-radiation times induce bubbles growth or defects nucleation within the sample, decreasing composite performance. On the basis of such results microwave curing activation of polyester resin based composites could be proposed as a valid alternative method for faster processing of laminated materials employed for large-scale applications.

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.

Bayesian transformation cure frailty models with multivariate failure time data.

PubMed

Yin, Guosheng

2008-12-10

We propose a class of transformation cure frailty models to accommodate a survival fraction in multivariate failure time data. Established through a general power transformation, this family of cure frailty models includes the proportional hazards and the proportional odds modeling structures as two special cases. Within the Bayesian paradigm, we obtain the joint posterior distribution and the corresponding full conditional distributions of the model parameters for the implementation of Gibbs sampling. Model selection is based on the conditional predictive ordinate statistic and deviance information criterion. As an illustration, we apply the proposed method to a real data set from dentistry.

Shear bond strength of a bracket-bonding system cured with a light-emitting diode or halogen-based light-curing unit at various polymerization times

PubMed Central

Gupta, Sanjay Prasad; Shrestha, Basanta Kumar

2018-01-01

Purpose To determine and compare the shear bond strength (SBS) of bracket-bonding system cured with light-emitting diode (LED) and halogen-based light-curing unit at various polymerization times. Materials and methods Ninety six human maxillary premolar teeth extracted for orthodontic purpose were divided into four groups, according to the light-curing unit and exposure times used. In the halogen group, the specimens were light cured for 20 and 40 seconds. In the LED group, the specimens were light cured for 5 and 10 seconds. Stainless steel brackets were bonded with Enlight bonding system, stored in distilled water at 37°C for 24 hours and then submitted to SBS testing in a universal testing machine at a crosshead speed of 0.5 mm/minute. Adhesive remnant index (ARI) was used to evaluate the amount of adhesive remaining on the teeth determined by stereomicroscope at 10× magnification. Results The highest mean SBS was obtained with the halogen 40 seconds (18.27 MPa) followed by halogen 20 seconds (15.36 MPa), LED 10 seconds (14.60 MPa) and least with LED 5 seconds (12.49 MPa) group. According to analysis of variance (ANOVA) and Tukey’s multiple-comparison test, SBS of halogen 20 seconds group was not significantly different from halogen 40 seconds group, LED 5 seconds group and LED 10 seconds group, whereas halogen 40 seconds group was significantly different from LED 5 seconds and LED 10 seconds group. The method of light curing did not influence the ARI, with score 2 being predominant. Conclusion Polymerization with both halogen and LED resulted in SBS values that were clinically acceptable for orthodontic treatment in all groups. Hence, for bonding orthodontic brackets, photoactivation with halogen for 20 seconds and LED for 5 seconds is suggested. PMID:29692633

Influence of polymerization time and depth of cure of resin composites determined by Vickers hardness.

PubMed

Lombardini, Marco; Chiesa, Marco; Scribante, Andrea; Colombo, Marco; Poggio, Claudio

2012-11-01

Adequate polymerization of resin composites could be considered as a crucial factor in obtaining good clinical performance, particularly in stress-bearing areas. An insufficient curing degree affects the resin composite's chemical properties The current in vitro study evaluated the influence of polymerization time and depth of cure of six commercial resin composites by Vickers microhardness (VK). SIX RESIN COMPOSITES WERE SELECTED: Three microhybrid (Esthet.X HD, Amaris, Filtek Silorane), two nanohybrid (Grandio, Ceram.X mono), and one nanofilled (Filtek Supreme XT). The VK of the surface was determined by a microhardness tester using a Vickers diamond indenter and a 200 g load applied for 15 s. The bottom to top mean VK ratio was calculated using the formula: Hardness ratio = VK of bottom surface/VK of top surface. Vickers hardness values of test materials during exposure time of 20 and 40 s and depths of cure of 2 and 3 mm were determined and compared. Data were analyzed using analysis of variance (ANOVA) test. For all the tested materials and with all the exposure time periods, hardness ratio was higher than the minimum value indicated in literature (0.8). Exposure time and depth of cure did not affect hardness ratio values for Filtek Silorane, Grandio, and Filtek Supreme XT. Among the materials tested, the nanofilled and the nanohybrid resin composites were rather insensible to thickness variations. Miicrohybrid composites, instead, had features different from one another.

Effects of Light Curing Method and Exposure Time on Mechanical Properties of Resin Based Dental Materials

PubMed Central

Alpöz, A. Riza; Ertuḡrul, Fahinur; Cogulu, Dilsah; Ak, Asli Topaloḡlu; Tanoḡlu, Metin; Kaya, Elçin

2008-01-01

Objectives The aim of this study was to investigate microhardness and compressive strength of composite resin (Tetric-Ceram, Ivoclar Vivadent), compomer (Compoglass, Ivoclar, Vivadent), and resin modified glass ionomer cement (Fuji II LC, GC Corp) polymerized using halogen light (Optilux 501, Demetron, Kerr) and LED (Bluephase C5, Ivoclar Vivadent) for different curing times. Methods Samples were placed in disc shaped plastic molds with uniform size of 5 mm diameter and 2 mm in thickness for surface microhardness test and placed in a diameter of 4 mm and a length of 2 mm teflon cylinders for compressive strength test. For each subgroup, 20 samples for microhardness (n=180) and 5 samples for compressive strength were prepared (n=45). In group 1, samples were polymerized using halogen light source for 40 seconds; in group 2 and 3 samples were polymerized using LED light source for 20 seconds and 40 seconds respectively. All data were analyzed by two way analysis of ANOVA and Tukey’s post-hoc tests. Results Same exposure time of 40 seconds with a low intensity LED was found similar or more efficient than a high intensity halogen light unit (P>.05), however application of LED for 20 seconds was found less efficient than 40 seconds curing time (P=.03). Conclusions It is important to increase the light curing time and use appropriate light curing devices to polymerize resin composite in deep cavities to maximize the hardness and compressive strength of restorative materials. PMID:19212507

A multivariate cure model for left-censored and right-censored data with application to colorectal cancer screening patterns.

PubMed

Hagar, Yolanda C; Harvey, Danielle J; Beckett, Laurel A

2016-08-30

We develop a multivariate cure survival model to estimate lifetime patterns of colorectal cancer screening. Screening data cover long periods of time, with sparse observations for each person. Some events may occur before the study begins or after the study ends, so the data are both left-censored and right-censored, and some individuals are never screened (the 'cured' population). We propose a multivariate parametric cure model that can be used with left-censored and right-censored data. Our model allows for the estimation of the time to screening as well as the average number of times individuals will be screened. We calculate likelihood functions based on the observations for each subject using a distribution that accounts for within-subject correlation and estimate parameters using Markov chain Monte Carlo methods. We apply our methods to the estimation of lifetime colorectal cancer screening behavior in the SEER-Medicare data set. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Evaluation of the effect of physical variables on in vitro release of diclofenac pellets using Box-Behnken design

PubMed Central

Enayatifard, Reza; Mahjoob, Aiding; Ebrahimi, Pouneh; Ebrahimnejad, Pedram

2015-01-01

Objective(s): A Box-Behnken design was used for evaluation of Eudragit coated diclofenac pellets. The purpose of this work was to optimize diclofenac pellets to improve the physicochemical properties using experimental design. Materials and Methods: Diclofenac was loaded onto the non-pareil beads using conventional coating pan. Film coating of pellets was done at the same pan. The effect of plasticizer level, curing temperature and curing time was determined on the release of diclofenac from pellets coated with polymethacrylates. Results: Increasing the plasticizer in the coating formula led to decrease in drug release and increasing the curing temperature and time resulted in higher drug release. The optimization process generated an optimum of 35% drug release at 3 hr. The level of plasticizer concentration, curing temperature and time were 20% w/w, 55 °C and 24 hr, respectively. Conclusion: This study showed that by controllinig the physical variables optimum drug release were obtained. PMID:26351563

Light curing in orthodontics; should we be concerned?

PubMed

McCusker, Neil; Lee, Siu Man; Robinson, Stephen; Patel, Naresh; Sandy, Jonathan R; Ireland, Anthony J

2013-06-01

Light cured materials are increasingly used in orthodontic clinical practice and concurrent with developments in materials have been developments in light curing unit technology. In recent years the irradiances of these units have increased. The aim of this study was to determine the safe exposure times to both direct and reflected light. The weighted irradiance and safe exposure times of 11 dental curing lights (1 plasma arc, 2 halogen and 8 LED lights) were determined at 6 distances (2-60 cm) from the light guide tip using a spectroradiometer. In addition, using the single most powerful light, the same two parameters were determined for reflected light. This was done at a distance of 10 cm from the reflected light, but during simulated bonding of 8 different orthodontic brackets of three material types, namely stainless steel, ceramic and composite. The results indicate that the LED Fusion lamp had the highest weighted irradiance and the shortest safe exposure time. With this light the maximum safe exposure time without additional eye protection for the patient (at 10 cm), the operator (at 30 cm) and the assistant (at 60 cm) ranged from 2.5 min, 22.1 min and 88.8 min respectively. This indicates a relatively low short term risk during normal operation of dental curing lights. For reflected light at a distance of 10 cm the risk was even lower, but was affected by the material and shape of the orthodontic bracket under test. The short term risks associated with the use of dental curing lights, halogen, LED or plasma, appear to be low, particularly if as is the case adequate safety precautions are employed. The same is true for reflected light from orthodontic brackets during bonding. What is still unclear is the potential long term ocular effects of prolonged exposure to the blue light generated from dental curing lights. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Physical properties and depth of cure of a new short fiber reinforced composite.

PubMed

Garoushi, Sufyan; Säilynoja, Eija; Vallittu, Pekka K; Lassila, Lippo

2013-08-01

To determine the physical properties and curing depth of a new short fiber composite intended for posterior large restorations (everX Posterior) in comparison to different commercial posterior composites (Alert, TetricEvoCeram Bulk Fill, Voco X-tra base, SDR, Venus Bulk Fill, SonicFill, Filtek Bulk Fill, Filtek Superme, and Filtek Z250). In addition, length of fiber fillers of composite XENIUS base compared to the previously introduced composite Alert has been measured. The following properties were examined according to ISO standard 4049: flexural strength, flexural modulus, fracture toughness, polymerization shrinkage and depth of cure. The mean and standard deviation were determined and all results were statistically analyzed with analysis of variance ANOVA (a=0.05). XENIUS base composite exhibited the highest fracture toughness (4.6MPam(1/2)) and flexural strength (124.3MPa) values and the lower shrinkage strain (0.17%) among the materials tested. Alert composite revealed the highest flexural modulus value (9.9GPa), which was not significantly different from XENIUS base composite (9.5GPa). Depth of cure of XENIUS base (4.6mm) was similar than those of bulk fill composites and higher than other hybrid composites. The length of fiber fillers in XENIUS base was longer (1.3-2mm) than in Alert (20-60μm). The new short fiber composite differed significantly in its physical properties compared to other materials tested. This suggests that the latter could be used in high-stress bearing areas. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Enhancing the compressive strength of landfill soil using cement and bagasse ash

NASA Astrophysics Data System (ADS)

Azim, M. A. M.; Azhar, A. T. S.; Tarmizi, A. K. A.; Shahidan, S.; Nabila, A. T. A.

2017-11-01

The stabilisation of contaminated soil with cement and agricultural waste is a widely applied method which contributes to the sustainability of the environment. Soil may be stabilised to increase strength and durability or to prevent erosion and other geotechnical failure. This study was carried out to evaluate the compressive strength of ex-landfill soil when cement and bagasse ash (BA) are added to it. Different proportions of cement (5%, 10%, 15% and 20%) was added to sample weights without BA. On the other hand, the cement in a different batch of sample weights was replaced by 2.5%, 5%, 7.5% and 10% of BA. All samples were allowed to harden and were cured at room temperature for 7, 14 and 28 days respectively. The strength of the contaminated soil was assessed using an unconfined compressive strength test (UCS). The laboratory tests also included the index properties of soil, cement and bagasse ash in raw form. The results indicated that the samples with cement achieved the highest compressive strength measuring 4.39 MPa. However, this study revealed that the use of bagasse ash produced low quality products with a reduction in strength. For example, when 5% of cement was replaced with 5% ash, the compressive strength decreased by about 54% from 0.72 MPa to 0.33 MPa. Similarly, the compressive strength of each sample after a curing period of 28 days was higher compared to samples cured for 7 and 14 days respectively. This is proved that a longer curing period is needed to increase the compressive strength of the samples.

Light curing through glass ceramics with a second- and a third-generation LED curing unit: effect of curing mode on the degree of conversion of dual-curing resin cements.

PubMed

Flury, Simon; Lussi, Adrian; Hickel, Reinhard; Ilie, Nicoleta

2013-12-01

The aim of this study was to measure the degree of conversion (DC) of five dual-curing resin cements after different curing modes with a second- and a third-generation light-emitting diode (LED) curing unit. Additionally, irradiance of both light curing units was measured at increasing distances and through discs of two glass ceramics for computer-aided design/manufacturing (CAD/CAM). Irradiance and spectra of the Elipar FreeLight 2 (Standard Mode (SM)) and of the VALO light curing unit (High Power Mode (HPM) and Xtra Power Mode (XPM)) were measured with a MARC radiometer. Irradiance was measured at increasing distances (control) and through discs (1.5 to 6 mm thickness) of IPS Empress CAD and IPS e.max CAD. DC of Panavia F2.0, RelyX Unicem 2 Automix, SpeedCEM, BisCem, and BeautiCem SA was measured with an attenuated total reflectance-Fourier transform infrared spectrometer when self-cured (negative control) or light cured in SM for 40 s, HPM for 32 s, or XPM for 18 s. Light curing was performed directly (positive control) or through discs of either 1.5- or 3-mm thickness of IPS Empress CAD or IPS e.max CAD. DC was analysed with Kruskal-Wallis tests followed by pairwise Wilcoxon rank sum tests (α = 0.05). Maximum irradiances were 1,545 mW/cm(2) (SM), 2,179 mW/cm(2) (HPM), and 4,156 mW/cm(2) (XPM), and all irradiances decreased by >80 % through discs of 1.5 mm, ≥95 % through 3 mm, and up to >99 % through 6 mm. Generally, self-curing resulted in the lowest DC. For some cements, direct light curing did not result in higher DC compared to when light cured through ceramic discs. For other cements, light curing through ceramic discs of 3 mm generally reduced DC. Light curing was favourable for dual-curing cements. Some cements were more susceptible to variations in curing mode than others. When light curing a given cement, the higher irradiances of the third-generation LED curing unit resulted in similar DC compared to the second-generation one, though at shorter light curing times.

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.

Computational methods for yeast prion curing curves.

PubMed

Ridout, Martin S

2008-10-01

If the chemical guanidine hydrochloride is added to a dividing culture of yeast cells in which some of the protein Sup35p is in its prion form, the proportion of cells that carry replicating units of the prion, termed propagons, decreases gradually over time. Stochastic models to describe this process of 'curing' have been developed in earlier work. The present paper investigates the use of numerical methods of Laplace transform inversion to calculate curing curves and contrasts this with an alternative, more direct, approach that involves numerical integration. Transform inversion is found to provide a much more efficient computational approach that allows different models to be investigated with minimal programming effort. The method is used to investigate the robustness of the curing curve to changes in the assumed distribution of cell generation times. Matlab code is available for carrying out the calculations.

Surveillance of colorectal cancer: effectiveness of early detection of intraluminal recurrences on prognosis and survival of patients treated for cure.

PubMed

Barillari, P; Ramacciato, G; Manetti, G; Bovino, A; Sammartino, P; Stipa, V

1996-04-01

The authors evaluate the effectiveness of routine colonoscopy and marker evaluation in diagnosis of intraluminal recurrent cancer. Chart review was conducted on 481 patients who underwent curative resection for colorectal cancer between 1980 and 1990. Clinical visits were scheduled and carcinoembryonic antigen evaluation was performed every three months, and colonoscopy was performed preoperatively, 12 to 15 months after surgical treatment, and then with intervals of 12 to 24 months or when symptoms appeared. About 10 percent of patients developed intraluminal recurrences. More than one-half of metachronous lesions arose within the first 24 months, and median time to diagnosis was 25 months. Patients with left-sited tumors in the advanced stage had a higher risk of developing recurrent intraluminal disease. Twenty-nine patients underwent a second surgical operation, of which 17 cases were radical. In this group, the five-year survival was 70.6 percent, although no nonradically treated or nonresected patients survived longer than 31 months. Twenty-two patients were asymptomatic at time of diagnosis of recurrence, and of these, 12 patients underwent radical operation; on the other hand, of the 24 symptomatic patients, only 5 were treated radically. Carcinoembryonic antigen was the first sign of recurrence in eight cases. Colonoscopy must be performed within the first 12 to 15 months after operation, whereas an interval of 24 months between examinations seems sufficient to guarantee early detection of metachronous lesions. Serial tumor marker evaluation is of help in earlier diagnosis of local recurrences. Asymptomatic patients more frequently undergo another operation for cure and thus have a better survival rate.

The Topp-Leone generalized Rayleigh cure rate model and its application

NASA Astrophysics Data System (ADS)

Nanthaprut, Pimwarat; Bodhisuwan, Winai; Patummasut, Mena

2017-11-01

Cure rate model is one of the survival analysis when model consider a proportion of the censored data. In clinical trials, the data represent time to recurrence of event or death of patients are used to improve the efficiency of treatments. Each dataset can be separated into two groups: censored and uncensored data. In this work, the new mixture cure rate model is introduced based on the Topp-Leone generalized Rayleigh distribution. The Bayesian approach is employed to estimate its parameters. In addition, a breast cancer dataset is analyzed for model illustration purpose. According to the deviance information criterion, the Topp-Leone generalized Rayleigh cure rate model shows better result than the Weibull and exponential cure rate models.

Time dependence of composite shrinkage using halogen and LED light curing.

PubMed

Uhl, Alexander; Mills, Robin W; Rzanny, Angelika E; Jandt, Klaus D

2005-03-01

The polymerization shrinkage of light cured dental composites presents the major drawback for these aesthetically adaptable restorative materials. LED based light curing technology has recently become commercially available. Therefore, the aim of the present study was to investigate if there was a statistically significant difference in linear and volumetric composite shrinkage strain if a LED LCU is used for the light curing process rather than a conventional halogen LCU. The volumetric shrinkage strain was determined using the Archimedes buoyancy principle after 5, 10, 20, 40 s of light curing and after 120 s following the 40 s light curing time period. The linear shrinkage strain was determined with a dynamic mechanical analyzer for the composites Z100, Spectrum, Solitaire2 and Definite polymerized with the LCUs Trilight (halogen), Freelight I (LED) and LED63 (LED LCU prototype). The changes in irradiance and spectra of the LCUs were measured after 0, 312 and 360 min of duty time. In general there was no considerable difference in shrinkage of the composites Z100, Spectrum or Solitaire2 when the LED63 was used instead of the Trilight. There was, however, a statistically significant difference in shrinkage strain when the composite Definite was polymerized with the LED63 instead of the Trilight. The spectrum of the Trilight changed during the experiment considerably whereas the LED63 showed an almost constant light output. The Freelight I dropped considerably in irradiance and had to be withdrawn from the study because of technical problems. The composites containing only the photoinitiator camphorquinone showed similar shrinkage strain behaviour when a LED or halogen LCU is used for the polymerization. The irradiance of some LED LCUs can also decrease over time and should therefore be checked on a regular basis.

Chemoviscosity modeling for thermosetting resins, 2

NASA Technical Reports Server (NTRS)

Hou, T. H.

1985-01-01

A new analytical model for simulating chemoviscosity of thermosetting resin was formulated. The model is developed by modifying the Williams-Landel-Ferry (WLF) theory in polymer rheology for thermoplastic materials. By assuming a linear relationship between the glass transition temperature and the degree of cure of the resin system under cure, the WLF theory can be modified to account for the factor of reaction time. Temperature dependent functions of the modified WLF theory constants were determined from the isothermal cure data of Lee, Loos, and Springer for the Hercules 3501-6 resin system. Theoretical predictions of the model for the resin under dynamic heating cure cycles were shown to compare favorably with the experimental data reported by Carpenter. A chemoviscosity model which is capable of not only describing viscosity profiles accurately under various cure cycles, but also correlating viscosity data to the changes of physical properties associated with the structural transformations of the thermosetting resin systems during cure was established.

Curing behavior and reaction kinetics of binder resins for 3D-printing investigated by dielectric analysis (DEA)

NASA Astrophysics Data System (ADS)

Möginger, B.; Kehret, L.; Hausnerova, B.; Steinhaus, J.

2016-05-01

3D-Printing is an efficient method in the field of additive manufacturing. In order to optimize the properties of manufactured parts it is essential to adapt the curing behavior of the resin systems with respect to the requirements. Thus, effects of resin composition, e.g. due to different additives such as thickener and curing agents, on the curing behavior have to be known. As the resin transfers from a liquid to a solid glass the time dependent ion viscosity was measured using DEA with flat IDEX sensors. This allows for a sensitive measurement of resin changes as the ion viscosity changes two to four decades. The investigated resin systems are based on the monomers styrene and HEMA. To account for the effects of copolymerization in the calculation of the reaction kinetics it was assumed that the reaction can be considered as a homo-polymerization having a reaction order n≠1. Then the measured ion viscosity curves are fitted with the solution of the reactions kinetics - the time dependent degree of conversion (DC-function) - for times exceeding the initiation phase representing the primary curing. The measured ion viscosity curves can nicely be fitted with the DC-function and the determined fit parameters distinguish distinctly between the investigated resin compositions.

Effects of various light curing methods on the leachability of uncured substances and hardness of a composite resin.

PubMed

Moon, H-J; Lee, Y-K; Lim, B-S; Kim, C-W

2004-03-01

The purpose of this study was to evaluate the effect of the various light curing units (plasma arc, halogen and light-emitting diodes) and irradiation methods (one-step, two-step and pulse) using different light energy densities on the leachability of unreacted monomers (Bis-GMA and UDMA) and the surface hardness of a composite resin (Z250, 3M). Leachability of the specimens immersed for 7 days in ethanol was analysed by HPLC. Vicker's hardness number (VHN) was measured immediately after curing (IC) and after immersion in ethanol for 7 days. Various irradiation methods with three curing units resulted in differences in the amount of leached monomers and VHN of IC when light energy density was lower than 17.0 J cm(-2) (P = 0.05). However, regardless of curing units and irradiation methods, these results were not different when the time or light energy density increased. When similar light energy density was irradiated (15.6-17.7 J cm(-2)), the efficiency of irradiation methods was different by the following order: one-step > or = two-step > pulse. These results suggest that the amount of leached monomers and VHN were influenced by forming polymer structure in activation and initiation stages of polymerization process with different light source energies and curing times.

A novel injectable borate bioactive glass cement for local delivery of vancomycin to cure osteomyelitis and regenerate bone.

PubMed

Cui, Xu; Zhao, Cunju; Gu, Yifei; Li, Le; Wang, Hui; Huang, Wenhai; Zhou, Nai; Wang, Deping; Zhu, Yi; Xu, Jun; Luo, Shihua; Zhang, Changqing; Rahaman, Mohamed N

2014-03-01

Osteomyelitis (bone infection) is often difficult to cure. The commonly-used treatment of surgical debridement to remove the infected bone combined with prolonged systemic and local antibiotic treatment has limitations. In the present study, an injectable borate bioactive glass cement was developed as a carrier for the antibiotic vancomycin, characterized in vitro, and evaluated for its capacity to cure osteomyelitis in a rabbit tibial model. The cement (initial setting time = 5.8 ± 0.6 min; compressive strength = 25.6 ± 0.3 MPa) released vancomycin over ~25 days in phosphate-buffered saline, during which time the borate glass converted to hydroxyapatite (HA). When implanted in rabbit tibial defects infected with methicillin-resistant Staphylococcus aureus (MRSA)-induced osteomyelitis, the vancomycin-loaded cement converted to HA and supported new bone formation in the defects within 8 weeks. Osteomyelitis was cured in 87 % of the defects implanted with the vancomycin-loaded borate glass cement, compared to 71 % for the defects implanted with vancomycin-loaded calcium sulfate cement. The injectable borate bioactive glass cement developed in this study is a promising treatment for curing osteomyelitis and for regenerating bone in the defects following cure of the infection.

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. Copyright © 2013 Elsevier B.V. All rights reserved.

Residual Stress Developed During the Cure of Thermosetting Polymers: Optimizing Cure Schedule to Minimize Stress.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kropka, Jamie Michael; Stavig, Mark E.; Jaramillo, Rex

When thermosetting polymers are used to bond or encapsulate electrical, mechanical or optical assemblies, residual stress, which often affects the performance and/or reliability of these devices, develops within the structure. The Thin-Disk-on-Cylinder structural response test is demonstrated as a powerful tool to design epoxy encapsulant cure schedules to reduce residual stress, even when all the details of the material evolution during cure are not explicitly known. The test's ability to (1) distinguish between cohesive and adhesive failure modes and (2) demonstrate methodologies to eliminate failure and reduce residual stress, make choices of cure schedules that optimize stress in the encapsulantmore » unambiguous. For the 828/DEA/GMB material in the Thin-Disk-on-Cylinder geometry, the stress associated with cure is significant and outweighs that associated with cool down from the final cure temperature to room temperature (for measured lid strain, Scure I > I I e+h erma * II) * The difference between the final cure temperature and 1 1 -- the temperature at which the material gels, Tf-T ge i, was demonstrated to be a primary factor in determining the residual stress associated with cure. Increasing T f -T ge i leads to a reduction in cure stress that is described as being associated with balancing some of the 828/DEA/GMB cure shrinkage with thermal expansion. The ability to tune residual stress associated with cure by controlling T f -T ge i would be anticipated to translate to other thermosetting encapsulation materials, but the times and temperatures appropriate for a given material may vary widely.« less

Cytotoxicity of four categories of dental cements.

PubMed

Schmid-Schwap, Martina; Franz, Alexander; König, Franz; Bristela, Margit; Lucas, Trevor; Piehslinger, Eva; Watts, David C; Schedle, Andreas

2009-03-01

Assessment of dental material biocompatibility is gaining increasing importance for both patients and dentists. Dental cements may be in contact with oral soft tissues for prolonged periods of time and play an important role in prosthetic rehabilitation. The aim of the present study was to evaluate eight dental cements using a standardized L929-fibroblast cell culture test. For each material, fresh specimens (added to the cultures immediately after preparation) and specimens preincubated for 7 days in cell culture medium were prepared according to the manufacturers' recommendations. After exposure to test specimens, cell numbers were compared to glass controls. The main outcome was a two-sided 95% confidence interval for the mean value of the standardized cell number for each substance investigated. Fresh specimens of all tested cements showed significant cytotoxicity, which diminished after 7 days preincubation. Cytotoxicity of fresh adhesive and self-adhesive resin cements was lower when specimens were dual-cured compared to self-cured. A rank order of cytotoxicity was established based on mean values: Nexus 2 (dual-cured) showed least cytotoxicity, followed by Variolink II (dual-cured), Nexus 2 (self-cured), Harvard, RelyxUnicem (dual-cured), Panavia 21, Fujicem, Durelon, Variolink II (self-cured), RelyxUnicem (self-cured), Maxcem (dual-cured) and Maxcem (self-cured). When bondings were added to Nexus 2 or Variolink II specimens, a slight increase in cytotoxicity was observed. Adhesive resin cements showed less cytotoxicity than self-adhesive and chemically setting cements. Bonding only slightly influenced cytotoxicity of the adhesive resin cements. Dual-cured specimens of adhesive and self-adhesive resin cements showed significantly less toxicity than self-cured specimens.

Palliative healthcare: cost reduction and quality enhancement using end-of-life survey methodology.

PubMed

Falls, Christopher Edward

2008-01-01

American medical institutions throughout the 20th century prescribed high customer satisfaction, but when it came to death, largely ignored it. An accelerated accumulation of esoteric medical information and the application of this knowledge to affect new cures and longer lives instilled an unquestioning reverence for the medical community among the patient population. Diminishing marginal gains in life expectancy, escalating costs related to life sustaining technologies, and a psychographic shift in the dominant consumer base have challenged this traditional reverence. Armed with unprecedented access to medical information, a more knowledgeable and assertive patient population has emerged in the 21st century to institute its own standards of what constitutes quality health care. In terms of end of life care, this has meant recognition that the emotional needs of the dying have been largely underserved by the current American medical model. Patients and their families are no longer willing to accept the traditional medical perspective of death as failure and have numerous international palliative care models that serve as benchmarks of success when it comes to quality of dying. When cure is a possibility, Americans will pursue it at all costs, but when it is not a possibility, they want honest communication and the opportunity to say good-bye to their loved ones. In the context of these emergent needs, life review is offered as a solution. The value proposition targets not only dying patients and their families, but also society as a whole.

Cure models for estimating hospital-based breast cancer survival.

PubMed

Rama, Ranganathan; Swaminathan, Rajaraman; Venkatesan, Perumal

2010-01-01

Research on cancer survival is enriched by development and application of innovative analytical approaches in relation to standard methods. The aim of the present paper is to document the utility of a mixture model to estimate the cure fraction and compare it with other approaches. The data were for 1,107 patients with locally advanced breast cancer, who completed the neo-adjuvant treatment protocol during 1990-99 at the Cancer Institute (WIA), Chennai, India. Tumour stage, post-operative pathological node (PN) and tumour residue (TR) status were studied. Event free survival probability was estimated using the Kaplan-Meier method. Cure models under proportional and non-proportional hazard assumptions following log normal distribution for survival time were used to estimate both the cure fraction and the survival function for the uncured. Event free survival at 5 and 10 years were 64.2% and 52.6% respectively and cure fraction was 47.5% for all cases together. Follow up ranged between 0-15 years and survival probabilities showed minimal changes after 7 years of follow up. TR and PN emerged as independent prognostic factors using Cox and proportional hazard (PH) cure models. Proportionality condition was violated when tumour stage was considered and it was statistically significant only under PH and not under non PH cure models. However, TR and PN continued to be independent prognostic factors after adjusting for tumour stage using the non PH cure model. A consistent ordering of cure fractions with respect to factors of PN and TR was forthcoming across tumour stages using PH and non PH cure models, but perceptible differences in survival were observed between the two. If PH conditions are violated, analysis using a non PH model is advocated and mixture cure models are useful in estimating the cure fraction and constructing survival curves for non-cures.

Use of natural ingredients to control growth of Clostridium perfringens in naturally cured frankfurters and hams.

PubMed

Jackson, Armitra L; Kulchaiyawat, Charlwit; Sullivan, Gary A; Sebranek, Joseph G; Dickson, James S

2011-03-01

A major concern for processed meats marketed as natural/organic is that they do not contain nitrite in concentrations known to be most effective for inhibiting foodborne pathogens. Supplemental treatments to increase the level and consistency of antimicrobial protection in these products may be important to provide consumers with the degree of safety that they have come to expect from conventionally cured meats. Therefore, the objective of this study was to identify and test ingredients that might improve processed meat product safety without altering their natural/organic status. Eight treatments of hams and frankfurters were prepared: (A) uncured control (typical ingredients except nitrite and nitrate); (B) conventionally cured control (erythorbate, nitrite, and a lactate-diacetate blend); (C) natural nitrate cure (including starter culture containing Staphylococcus carnosus); (D) natural nitrate cure (culture and natural antimicrobial A containing a vinegar, lemon, and cherry powder blend); (E) natural nitrate cure (culture and antimicrobial B containing a cultured sugar and vinegar blend); (F) natural nitrite cure without additional antimicrobials; (G) natural nitrite cure with natural antimicrobial A; and (H) natural nitrite cure with antimicrobial B. For the hams, treatments C, D, E, and H impacted growth of Clostridium perfringens to the same extent (P < 0.05) as the conventionally cured control (approximately 2 log less growth over time than uncured control). For frankfurters, treatments D, G, and H had an effect (approximately 1 log) on growth equivalent to that of the conventionally cured control (P < 0.05). These results suggest that natural/organic cured meats have more potential for pathogen growth than conventionally cured products, but supplemental natural ingredients offer safety improvement.

Treatment of cows with parturient paresis using intravenous calcium and oral sodium phosphate.

PubMed

Braun, U; Grob, D; Hässig, M

2016-09-01

The goal of this study was to investigate whether intravenous infusion of 1000 ml 40% calcium borogluconate combined with the oral adminstration of 500 g sodium phosphate leads to a better cure rate and longer-lasting normocalcaemia and normophosphataemia than standard intravenous treatment with 500 ml calcium borogluconate in cows with parturient paresis. Forty recumbent cows with hypocalcaemia and hypophosphataemia were alternately allocated to group A or B. Cows of both groups were treated intravenously with 500 ml 40% calcium borogluconate, and cows of group B additionally received another 500 ml calcium borogluconate via slow intravenous infusion and 500 g sodium phosphate administered via an orogastric tube. Thirty-two cows stood within 8 hours after the start of treatment and 8 did not; of the 32 cows that stood, 18 belonged to group A and 14 to group B (90% of group A vs. 70% of group B; P = 0.23). Seven cows relapsed; of these and the 8 that did not respond to initial treatment, 10 stood after two standard intravenous treatments. Downer cow syndrome occurred in 5 cows, 3 of which recovered after aggressive therapy. The overall cure rate did not differ significantly between groups A and B. Twelve (60%) cows of group A and 14 (70%) cows of group B were cured after a single treatment and of the remaining 14, 11 were cured after two or more treatments. Two downer cows were euthanized and one other died of heart failure during treatment. Serum calcium concentrations during the first eight hours after the start of treatment were significantly higher in group B than in group A, and oral sodium phosphate caused a significant and lasting increase in inorganic phosphate. More cows of group B than group A were cured after a single treatment (P > 0.05). These findings, although not statistically significant, are promising and should be verified using a larger number of cows.

Use of the Word "Cure" in the Oncology Literature.

PubMed

Prasad, Vinay

2015-08-01

"Cure" is an important word in oncology but its use in the published literature has not been examined. I investigated all oncology articles using cure in the title field and published in 2012. The definition of cure was examined, specifically whether or not authors use the word to connote some surviving subset of patients who go on to experience outcomes similar to age-matched, normal controls-a definition favored by researchers and employed in survival function analyses. All articles published between January 1, 2012, and December 31, 2012, with the word cure in the title field were retrieved from Thompson Reuters' Web of Science. After exclusions, articles were read in full to examine what definitions of cure was used. Additionally, for each situation (type of cancer, stage/grade) where the word cure was used, a literature search was performed to ascertain whether there existed documented cases of cure. Twenty-nine oncology articles used the word cure in their title in 2012. Nearly half, 14 (48%) of 29, used the term in situations (cancer type, stage/grade) currently considered incurable. Approximately one-third (34.5%) of the articles used the word consistent with the definition that, after a set period of time, some surviving subset of patients experience survival similar to normal controls. There is heterogeneity in the use of the word cure in the literature. © The Author(s) 2014.

Allogeneic bone marrow transplantation in multiple myeloma.

PubMed

Tura, S; Cavo, M

1992-04-01

The use of high-dose chemoradiotherapy with allogeneic hemopoietic stem cell support for the treatment of MM began about a decade ago. Because this procedure has been performed increasingly and because larger numbers of patients are being followed for longer periods of time, the proper role of allogeneic BMT in this setting is becoming clearer. Data available thus far indicate that such an approach results in a complete remission rate of at least 50% to 60%, and even higher if applied as consolidation treatment in the remission phase, a transplant-related mortality reported as 40% to 50% and a long-term survival plateau at around 40%. The 40% 5-year probability of relapse-free survival is considerably higher than that observed following autologous BMT and may result from an allogeneic graft-versus-tumor effect (graft versus myeloma) similar to the well-recognized graft-versus-leukemia effect. Although follow-up is still too short to clearly identify the likelihood of cure for MM allotransplant recipients, a certain number of them are currently long-term, disease-free survivors and--we hope--cured. These promising results and the incurability of MM with conventional chemotherapy should, therefore, encourage further application of allogeneic BMT to selected patients with unfavorable prognostic features. Continued efforts to reduce the morbidity and mortality related to the procedure, as well as to design effective pretransplant regimens with lower extramedullary toxicity and to identify those patients most likely to benefit from BMT, will improve the value of allogeneic BMT in MM.

Business continuity strategies for cyber defence: battling time and information overload.

PubMed

Streufert, John

2010-11-01

Can the same numbers and letters which are the life blood of modern business and government computer systems be harnessed to protect computers from attack against known information security risks? For the past seven years, Foreign Service officers and technicians of the US Government have sought to maintain diplomatic operations in the face of rising cyber attacks and test the hypothesis that an ounce of prevention is worth a pound of cure. As eight out of ten attacks leverage known computer security vulnerabilities or configuration setting weaknesses, a pound of cure would seem to be easy to come by. Yet modern security tools present an unusually consequential threat to business continuity - too much rather than too little information on cyber problems is presented, harking back to a phenomenon cited by social scientists in the 1960s called 'information overload'. Experience indicates that the longer the most serious cyber problems go untreated, the wider the attack surface adversaries can find. One technique used at the Department of State, called 'risk scoring', resulted in an 89 per cent overall reduction in measured risk over 12 months for the Department of State's servers and personal computers. Later refinements of risk scoring enabled technicians to correct unique security threats with unprecedented speed. This paper explores how the use of metrics, special care in presenting information to technicians and executives alike, as well as tactical use of organisational incentives can result in stronger cyber defences protecting modern organisations.

Long-term survival after childhood acute lymphoblastic leukaemia: population-based trends in cure and relapse by clinical characteristics.

PubMed

Smith, Lesley; Glaser, Adam W; Kinsey, Sally E; Greenwood, Darren C; Chilton, Lucy; Moorman, Anthony V; Feltbower, Richard G

2018-05-29

'Cure models' offer additional information to traditional epidemiological approaches to assess survival for cancer patients by simultaneously estimating the proportion cured and the survival of those 'uncured'. The proportion cured is a summary of long-term survival while the median survival time of the uncured provides important information on those who are not long-term survivors. Population-based trends in the cure proportion and survival of the uncured for childhood acute lymphoblastic leukaemia (ALL) by clinical prognostic risk factors were estimated using flexible parametric cure models, based on overall survival and event-free survival. Children aged 1-17 years diagnosed between 1990 and 2011 in Yorkshire, UK, were included (n = 492). The percentage cured increased from 77% (95% confidence interval 70-84%) in 1990-1997 to 89% (84-93%) in 2003-2011, while the median survival time of the uncured decreased from 3·2 years (2·2-4·1 years) to 0·7 years (0-1·5 years). Models based on event-free survival showed a similar trend. The 5-year cumulative incidence of relapse substantially decreased from 35% in 1990-97 to 9% in 2003-2011. These results show selective improvement in survival between 1990 and 2011 with a significant reduction in the risk of relapse alongside a reduced absolute duration of survival for those destined to be uncured. © 2018 John Wiley & Sons Ltd.

Trends in 'cure' fraction from colorectal cancer by age and tumour stage between 1975 and 2000, using population-based data, Osaka, Japan.

PubMed

Ito, Yuri; Nakayama, Tomio; Miyashiro, Isao; Sugimoto, Tomoyuki; Ioka, Akiko; Tsukuma, Hideaki; Abdel-Rahman, Manar E; Rachet, Bernard

2012-10-01

Since the 1960s, Japan has experienced a striking increase in the incidence of colorectal cancer, now the second most common cancer in the country. Meanwhile, the management of colorectal cancer has changed dramatically with the implementation of, for example, screening, endoscopy and adjuvant chemotherapy. It is therefore of interest to monitor the long-term trends in population 'cure' in Japan. We analysed 33 885 colorectal cancer cases diagnosed between 1975 and 2000 in Osaka. We applied the multivariable mixture cure model to estimate cure fraction and median survival time (MST) for 'uncured' patients, by sex, age, stage, period at diagnosis and subsite. For colon cancer, the cure fraction increased by about 25%, while MST for the uncured was prolonged from 8 to 12 months. The cure fraction was 5% higher in men than in women, while MST was similar in both. The cure fraction also increased for localized and regional tumours. For rectal cancer, the cure fraction increased by about 25-30%, but remained lower than for colon cancer. From the late 1970s, the cure fraction for colorectal cancer increased dramatically due to better management of detection and care for colorectal cancer. This improvement was obtained at the cost of shorter MST for uncured patients.

Intelligent sensor-model automated control of PMR-15 autoclave processing

NASA Technical Reports Server (NTRS)

Hart, S.; Kranbuehl, D.; Loos, A.; Hinds, B.; Koury, J.

1992-01-01

An intelligent sensor model system has been built and used for automated control of the PMR-15 cure process in the autoclave. The system uses frequency-dependent FM sensing (FDEMS), the Loos processing model, and the Air Force QPAL intelligent software shell. The Loos model is used to predict and optimize the cure process including the time-temperature dependence of the extent of reaction, flow, and part consolidation. The FDEMS sensing system in turn monitors, in situ, the removal of solvent, changes in the viscosity, reaction advancement and cure completion in the mold continuously throughout the processing cycle. The sensor information is compared with the optimum processing conditions from the model. The QPAL composite cure control system allows comparison of the sensor monitoring with the model predictions to be broken down into a series of discrete steps and provides a language for making decisions on what to do next regarding time-temperature and pressure.

Titanium dioxide nanotubes addition to self-adhesive resin cement: Effect on physical and biological properties.

PubMed

Ramos-Tonello, Carla M; Lisboa-Filho, Paulo N; Arruda, Larisa B; Tokuhara, Cintia K; Oliveira, Rodrigo C; Furuse, Adilson Y; Rubo, José H; Borges, Ana Flávia S

2017-07-01

This study has investigated the influence of Titanium dioxide nanotubes (TiO 2 -nt) addition to self-adhesive resin cement on the degree of conversion, water sorption, and water solubility, mechanical and biological properties. A commercially available auto-adhesive resin cement (RelyX U200™, 3M ESPE) was reinforced with varying amounts of nanotubes (0.3, 0.6, 0.9wt%) and evaluated at different curing modes (self- and dual cure). The DC in different times (3, 6, 9, 12 and 15min), water sorption (Ws) and solubility (Sl), 3-point flexural strength (σf), elastic modulus (E), Knoop microhardness (H) and viability of NIH/3T3 fibroblasts were performed to characterize the resin cement. Reinforced self-adhesive resin cement, regardless of concentration, increased the DC for the self- and dual-curing modes at all times studied. The concentration of the TiO 2 -nt and the curing mode did not influence the Ws and Sl. Regarding σf, concentrations of both 0.3 and 0.9wt% for self-curing mode resulted in data similar to that of dual-curing unreinforced cement. The E increased with the addition of 0.9wt% for self-cure mode and H increased with 0.6 and 0.9wt% for both curing modes. Cytotoxicity assays revealed that reinforced cements were biocompatible. TiO 2 -nt reinforced self-adhesive resin cement are promising materials for use in indirect dental restorations. Taken together, self-adhesive resin cement reinforced with TiO 2 -nt exhibited physicochemical and mechanical properties superior to those of unreinforced cements, without compromising their cellular viability. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Vulcanization characteristics and dynamic mechanical behavior of natural rubber reinforced with silane modified silica.

PubMed

Chonkaew, Wunpen; Minghvanish, Withawat; Kungliean, Ulchulee; Rochanawipart, Nutthaya; Brostow, Witold

2011-03-01

Two silane coupling agents were used for hydrolysis-condensation reaction modification of nanosilica surfaces. The surface characteristics were analyzed using Fourier transform infrared spectroscopy (FTIR). The vulcanization kinetics of natural rubber (NR) + silica composites was studied and compared to behavior of the neat NR using differential scanning calorimetry (DSC) in the dynamic scan mode. Dynamic mechanical analysis (DMA) was performed to evaluate the effects of the surface modification. Activation energy E(a) values for the reaction are obtained. The presence of silica, modified or otherwise, inhibits the vulcanization reaction of NR. The neat silica containing system has the lowest cure rate index and the highest activation energy for the vulcanization reaction. The coupling agent with longer chains causes more swelling and moves the glass transition temperature T(g) downwards. Below the glass transition region, silica causes a lowering of the dynamic storage modulus G', a result of hindering the cure reaction. Above the glass transition, silica-again modified or otherwise-provides the expected reinforcement effect.

Pharmacokinetics and therapeutic efficacy of gentamicin in an experimental pleural empyema rabbit model.

PubMed Central

Shohet, I; Yellin, A; Meyerovitch, J; Rubinstein, E

1987-01-01

The pharmacokinetics and therapeutic efficacy of gentamicin were investigated in an experimental pleural empyema rabbit model. Pleural effusion was induced by the intrapleural administration of turpentine, and empyema was induced by direct inoculation of the effusion with Klebsiella pneumoniae. Pleural empyema compared with effusion was characterized by lower pH, oxygen tension (PaO2), and glucose levels and higher leukocyte count, lactic acid concentration, and PaCO2. After a single administration, gentamicin was first detectable in the pleural fluid at 60 min, whereas peak levels in empyema were observed at 180 min. Gentamicin persisted in the empyema longer than in blood. Animals treated with gentamicin only had 60% bacterial cure on day 7; those treated with gentamicin in an oxygen chamber had 100% cure on day 5 (P = 0.004). Low oxygen tension diminished the antibacterial efficacy of gentamicin in this model. An increase in oxygen tension improved the therapeutic results without alteration of the pharmacokinetics of gentamicin. PMID:3116920

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.

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.

[Methods Used for Monitoring Cure Reactions in Real-time in an Autoclave

NASA Technical Reports Server (NTRS)

Cooper, John B.; Wise, Kent L.; Jensen, Brian J. (Technical Monitor)

2000-01-01

The goal of the research was to investigate methods for monitoring cure reactions in real-time in an autoclave. This is of particular importance to NASA Langley Research Center because polyimides were proposed for use in the High Speed Civil Transport (HSCT) program. Understanding the cure chemistry behind the polyimides would allow for intelligent processing of the composites made from their use. This work has led to two publications in peer-reviewed journals and a patent. The journal articles are listed as Appendix A which is on the instrument design of the research and Appendix B which is on the cure chemistry. Also, a patent has been awarded for the instrumental design developed under this grant which is given as Appendix C. There has been a significant amount of research directed at developing methods for monitoring cure reactions in real-time within the autoclave. The various research efforts can be categorized as methods providing either direct chemical bonding information or methods that provide indirect chemical bonding information. Methods falling into the latter category are fluorescence, dielectric loss, ultrasonic and similar type methods. Correlation of such measurements with the underlying chemistry is often quite difficult since these techniques do not allow monitoring of the curing chemistry which is ultimately responsible for material properties. Direct methods such as vibrational spectroscopy, however, can often be easily correlated with the underlying chemistry of a reaction. Such methods include Raman spectroscopy, mid-IR absorbance, and near-IR absorbance. With the recent advances in fiber-optics, these spectroscopic techniques can be applied to remote on-line monitoring.

Rapid Prototyping of Composite Structures

NASA Technical Reports Server (NTRS)

Colton, Jonathan S.

1998-01-01

This progress report for the project Rapid Production of Composite Structures covers the period from July 14, 1997 to June 30, 1998. It will present a short overview of the project, followed by the results to date and plans for the future. The goal of this research is to provide a minimum 100x reduction in the time required to produce arbitrary, laminated products without the need for a separate mold or an autoclave. It will accomplish this by developing the science underlying the rapid production of composite structures, specifically those of carbon fiber-epoxy materials. This scientific understanding will be reduced to practice in a demonstration device that will produce a part on the order of 12" by 12" by 6". Work in the past year has focussed on developing an understanding of the materials issues and of the machine design issues. Our initial goal was to use UV cureable resins to accomplish full cure on the machine. Therefore, we have centered our materials work around whether or not UV cureable resins will work. Currently, the answer seems to be that they will not work, because UV light cannot penetrate the carbon fibers, and because no "shadow" curing seems to occur. As a result, non-UV cureable resins are being investigated. This has resulted in a change in the machine design focus. We are now looking into a "dip and place" machine design, whereby a prepreg layer would have one side coated with a curing agent, and then would be placed onto the previous layer. This would lead to cure at the interface, but not to the top of the layer. The formulation of the resins to accomplish this task at room or slightly elevated temperatures is being investigated, as is the machine design needed to apply the curing agent and then cure or partially cure the part. A final, out-of-autoclave, post-cure may be needed with this strategy, as final cure on the machine may not be possible, as it was for the initial UV cure strategy. The remainder of this report details the progress in the materials and machine design areas. Materials Development The material system must be designed to fulfill the following requirements: to reduce the time and labor requirements of typical cure cycles; to reduce the thermal stresses developed during conventional heat curing; and to develop a structure that the build sequence requires. In order to accomplish these goals, there have been parallel tracks of investigation. One area has tested photopolymerizable (ultraviolet (UV) curable) materials and combinations of these materials with standard heat curing resins. The second area has investigated resins that cure rapidly at room or low heat temperatures. The main goal of these investigations has been to identify a system that will rapidly set or cure at room temperature during a tape lay-up process and hold its structure during a post-cure cycle.

Heat transfer properties and thermal cure of glass-ionomer dental cements.

PubMed

Gavic, Lidia; Gorseta, Kristina; Glavina, Domagoj; Czarnecka, Beata; Nicholson, John W

2015-10-01

Under clinical conditions, conventional glass-ionomer dental cements can be cured by application of heat from dental cure lamps, which causes acceleration in the setting. In order for this to be successful, such heat must be able to spread sufficiently through the cement to enhance cure, but not transmit heat so effectively that the underlying dental pulp of the tooth is damaged. The current study was aimed at measuring heat transfer properties of modern restorative glass-ionomers to determine the extent to which they meet these twin requirements. Three commercial glass ionomer cements (Ionofil Molar, Ketac Molar and Equia™ Fill) were used in association with three different light emitting diode cure lamps designed for clinical use. In addition, for each cement, one set of specimens was allowed to cure without application of a lamp. Temperature changes were measured at three different depths (2, 3 and 4 mm) after cure times of 20, 40 and 60 s. The difference among the tested groups was evaluated by ANOVA (P < 0.05) and post hoc Newman-Keuls test. All brands of glass-ionomer showed a small inherent setting exotherm in the absence of heat irradiation, but much greater temperature increases when exposed to the cure lamp. However, temperature rises did not exceed 12.9 °C. Application of the cure lamp led to the establishment of a temperature gradient throughout each specimen. Differences were typically significant (P < 0.05) and did not reflect the nominal power of the lamps, because those lamps have variable cooling systems, and are designed to optimize light output, not heating effect. Because the thermal conductivity of glass-ionomers is low, temperature rises at 4 mm depths were much lower than at 2 mm. At no time did the temperature rise sufficiently to cause concern about potential damage to the pulp.

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.

Quantitative genetics of taura syndrome resistance in pacific white shrimp (penaeus vannamei): a cure model approach

PubMed Central

2011-01-01

Background In aquaculture breeding, resistance against infectious diseases is commonly assessed as time until death under exposure to a pathogen. For some diseases, a fraction of the individuals may appear as "cured" (non-susceptible), and the resulting survival time may thus be a result of two confounded underlying traits, i.e., endurance (individual hazard) and susceptibility (whether at risk or not), which may be accounted for by fitting a cure survival model. We applied a cure model to survival data of Pacific white shrimp (Penaeus vannamei) challenged with the Taura syndrome virus, which is one of the major pathogens of Panaeid shrimp species. Methods In total, 15,261 individuals of 513 full-sib families from three generations were challenge-tested in 21 separate tests (tanks). All challenge-tests were run until mortality naturally ceased. Time-until-event data were analyzed with a mixed cure survival model using Gibbs sampling, treating susceptibility and endurance as separate genetic traits. Results Overall mortality at the end of test was 28%, while 38% of the population was considered susceptible to the disease. The estimated underlying heritability was high for susceptibility (0.41 ± 0.07), but low for endurance (0.07 ± 0.03). Furthermore, endurance and susceptibility were distinct genetic traits (rg = 0.22 ± 0.25). Estimated breeding values for endurance and susceptibility were only moderately correlated (0.50), while estimated breeding values from classical models for analysis of challenge-test survival (ignoring the cured fraction) were closely correlated with estimated breeding values for susceptibility, but less correlated with estimated breeding values for endurance. Conclusions For Taura syndrome resistance, endurance and susceptibility are apparently distinct genetic traits. However, genetic evaluation of susceptibility based on the cure model showed clear associations with standard genetic evaluations that ignore the cure fraction for these data. Using the current testing design, genetic variation in observed survival time and absolute survival at the end of test were most likely dominated by genetic variation in susceptibility. If the aim is to reduce susceptibility, earlier termination of the challenge-test or back-truncation of the follow-up period should be avoided, as this may shift focus of selection towards endurance rather than susceptibility. PMID:21418636

Comparison of transmission dynamics between Streptococcus uberis and Streptococcus agalactiae intramammary infections.

PubMed

Leelahapongsathon, Kansuda; Schukken, Ynte Hein; Pinyopummintr, Tanu; Suriyasathaporn, Witaya

2016-02-01

The objectives of study were to determine the transmission parameters (β), durations of infection, and basic reproductive numbers (R0) of both Streptococcus agalactiae and Streptococcus uberis as pathogens causing mastitis outbreaks in dairy herds. A 10-mo longitudinal study was performed using 2 smallholder dairy herds with mastitis outbreaks caused by Strep. agalactiae and Strep. uberis, respectively. Both herds had poor mastitis control management and did not change their milking management during the entire study period. Quarter milk samples were collected at monthly intervals from all lactating animals in each herd for bacteriological identification. The durations of infection for Strep. uberis intramammary infection (IMI) and Strep. agalactiae IMI were examined using Kaplan-Meier survival curves, and the Kaplan-Meier survival functions for Strep. uberis IMI and Strep. agalactiae IMI were compared using log rank survival-test. The spread of Strep. uberis and Strep. agalactiae through the population was determined by transmission parameter, β, the probability per unit of time that one infectious quarter will infect another quarter, assuming that all other quarters are susceptible. For the Strep. uberis outbreak herd (31 cows), 56 new infections and 28 quarters with spontaneous cure were observed. For the Strep. agalactiae outbreak herd (19 cows), 26 new infections and 9 quarters with spontaneous cure were observed. The duration of infection for Strep. agalactiae (mean=270.84 d) was significantly longer than the duration of infection for Strep. uberis (mean=187.88 d). The transmission parameters (β) estimated (including 95% confidence interval) for Strep. uberis IMI and Strep. agalactiae IMI were 0.0155 (0.0035-0.0693) and 0.0068 (0.0008-0.0606), respectively. The R0 (including 95% confidence interval) during the study were 2.91 (0.63-13.47) and 1.86 (0.21-16.61) for Strep. uberis IMI and Strep. agalactiae IMI, respectively. In conclusion, the transmission parameter and R0 values were not different between both pathogens; however, the duration of infection for Strep. agalactiae was longer than Strep. uberis. These suggest that Strep. uberis may have a different transmission dynamic compared with Strep. agalactiae. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Minimum follow-up time required for the estimation of statistical cure of cancer patients: verification using data from 42 cancer sites in the SEER database

PubMed Central

Tai, Patricia; Yu, Edward; Cserni, Gábor; Vlastos, Georges; Royce, Melanie; Kunkler, Ian; Vinh-Hung, Vincent

2005-01-01

Background The present commonly used five-year survival rates are not adequate to represent the statistical cure. In the present study, we established the minimum number of years required for follow-up to estimate statistical cure rate, by using a lognormal distribution of the survival time of those who died of their cancer. We introduced the term, threshold year, the follow-up time for patients dying from the specific cancer covers most of the survival data, leaving less than 2.25% uncovered. This is close enough to cure from that specific cancer. Methods Data from the Surveillance, Epidemiology and End Results (SEER) database were tested if the survival times of cancer patients who died of their disease followed the lognormal distribution using a minimum chi-square method. Patients diagnosed from 1973–1992 in the registries of Connecticut and Detroit were chosen so that a maximum of 27 years was allowed for follow-up to 1999. A total of 49 specific organ sites were tested. The parameters of those lognormal distributions were found for each cancer site. The cancer-specific survival rates at the threshold years were compared with the longest available Kaplan-Meier survival estimates. Results The characteristics of the cancer-specific survival times of cancer patients who died of their disease from 42 cancer sites out of 49 sites were verified to follow different lognormal distributions. The threshold years validated for statistical cure varied for different cancer sites, from 2.6 years for pancreas cancer to 25.2 years for cancer of salivary gland. At the threshold year, the statistical cure rates estimated for 40 cancer sites were found to match the actuarial long-term survival rates estimated by the Kaplan-Meier method within six percentage points. For two cancer sites: breast and thyroid, the threshold years were so long that the cancer-specific survival rates could yet not be obtained because the SEER data do not provide sufficiently long follow-up. Conclusion The present study suggests a certain threshold year is required to wait before the statistical cure rate can be estimated for each cancer site. For some cancers, such as breast and thyroid, the 5- or 10-year survival rates inadequately reflect statistical cure rates, and highlight the need for long-term follow-up of these patients. PMID:15904508

Degree of conversion of two lingual retainer adhesives cured with different light sources.

PubMed

Usümez, Serdar; Büyükyilmaz, Tamer; Karaman, Ali Ihya; Gündüz, Beniz

2005-04-01

The aim of this study was to evaluate the degree of conversion (DC) of two lingual retainer adhesives, Transbond Lingual Retainer (TLR) and Light Cure Retainer (LCR), cured with a fast halogen light, a plasma arc light and a light-emitting diode (LED) at various curing times. A conventional halogen light served as the control. One hundred adhesive samples (five per group) were cured for 5, 10 or 15 seconds with an Optilux 501 (fast halogen light), for 3, 6 or 9 seconds with a Power Pac (plasma arc light), or for 10, 20 or 40 seconds with an Elipar Freelight (LED). Samples cured for 40 seconds with the conventional halogen lamp were used as the controls. Absorbance peaks were recorded using Fourier transform infrared (FT-IR) spectroscopy. DC values were calculated. Data were analysed using Kruskal-Wallis and Mann-Whitney U-tests. For the TLR, the highest DC values were achieved in 6 and 9 seconds with the plasma arc light. Curing with the fast halogen light for 15 seconds and with the LED for 40 seconds produced statistically similar DC values, but these were lower than those with the plasma arc light. All of these light exposures yielded a statistically significantly higher DC than 40 seconds of conventional halogen light curing. The highest DC value for the LCR was achieved in 15 seconds with the fast halogen light, then the plasma arc light curing for 6 seconds. These two combinations produced a statistically significantly higher DC when compared with the 40 seconds of conventional halogen light curing. The lowest DC for the LCR was achieved with 10 seconds of LED curing. The overall DC of the LCR was significantly higher than that of the TLR. The results suggest that a similar or higher DC than the control values could be achieved in 6-9 seconds by plasma arc curing, in 10-15 seconds by fast halogen curing or in 20 seconds by LED curing.

Between remission and cure: patients, practitioners and the transformation of leukaemia in the late twentieth century.

PubMed

Barnes, Emm

2007-12-01

During the course of the 1960s and 1970s, acute leukaemia in childhood ceased to be invariably fatal and was recategorized as curable. The meaning of cure in this case, however, was problematic, as it was impossible for physicians to be certain that cancer would not return. This paper uses historical methods to explore how remission was understood by families with children with acute leukaemia during the period in which the first cures were announced, roughly 1972-77. These comprised documentary analysis of records of the Medical Research Council's leukaemia working parties, published papers and letters on treatments for childhood leukaemia, and interviews with eight UK paediatric oncologists practising in UK hospitals in the 1960s and 1970s. Two approaches to defining 'cure' in leukaemia can be identified. The first relied on statistical assessment of survival rates. I argue that the concept of 'indefinite remission' came to serve for researchers and clinicians as a proxy measure of cure. However, the concept of 'indefinite remission' left many patients and their families quite uncertain as to whether a cure had really happened. A second approach to defining cure therefore developed. Faced with uncertainty, patients, parents and psychologists sought to develop alternative measures of success--including the notion of 'psychological cure'--that brought forward the moment of cure and its relief. Changing conceptualizations of leukaemia shaped and were shaped by negotiations over the meaning of 'remission' and 'cure'. On the one hand, the statistical definition of cure was not available for years. On the other hand, psychological cure could begin from the time of first remission, even if medical absolution was not available for years.

Optimal cure cycle design for autoclave processing of thick composites laminates: A feasibility study

NASA Technical Reports Server (NTRS)

Hou, Jean W.

1985-01-01

The thermal analysis and the calculation of thermal sensitivity of a cure cycle in autoclave processing of thick composite laminates were studied. A finite element program for the thermal analysis and design derivatives calculation for temperature distribution and the degree of cure was developed and verified. It was found that the direct differentiation was the best approach for the thermal design sensitivity analysis. In addition, the approach of the direct differentiation provided time histories of design derivatives which are of great value to the cure cycle designers. The approach of direct differentiation is to be used for further study, i.e., the optimal cycle design.

Rapid energy-efficient manufacturing of polymers and composites via frontal polymerization.

PubMed

Robertson, Ian D; Yourdkhani, Mostafa; Centellas, Polette J; Aw, Jia En; Ivanoff, Douglas G; Goli, Elyas; Lloyd, Evan M; Dean, Leon M; Sottos, Nancy R; Geubelle, Philippe H; Moore, Jeffrey S; White, Scott R

2018-05-01

Thermoset polymers and composite materials are integral to today's aerospace, automotive, marine and energy industries and will be vital to the next generation of lightweight, energy-efficient structures in these enterprises, owing to their excellent specific stiffness and strength, thermal stability and chemical resistance 1-5 . The manufacture of high-performance thermoset components requires the monomer to be cured at high temperatures (around 180 °C) for several hours, under a combined external pressure and internal vacuum 6 . Curing is generally accomplished using large autoclaves or ovens that scale in size with the component. Hence this traditional curing approach is slow, requires a large amount of energy and involves substantial capital investment 6,7 . Frontal polymerization is a promising alternative curing strategy, in which a self-propagating exothermic reaction wave transforms liquid monomers to fully cured polymers. We report here the frontal polymerization of a high-performance thermoset polymer that allows the rapid fabrication of parts with microscale features, three-dimensional printed structures and carbon-fibre-reinforced polymer composites. Precise control of the polymerization kinetics at both ambient and elevated temperatures allows stable monomer solutions to transform into fully cured polymers within seconds, reducing energy requirements and cure times by several orders of magnitude compared with conventional oven or autoclave curing approaches. The resulting polymer and composite parts possess similar mechanical properties to those cured conventionally. This curing strategy greatly improves the efficiency of manufacturing of high-performance polymers and composites, and is widely applicable to many industries.

Light-Curing Volumetric Shrinkage in Dimethacrylate-Based Dental Composites by Nanoindentation and PAL Study.

PubMed

Shpotyuk, Olha; Adamiak, Stanislaw; Bezvushko, Elvira; Cebulski, Jozef; Iskiv, Maryana; Shpotyuk, Oleh; Balitska, Valentina

2017-12-01

Light-curing volumetric shrinkage in dimethacrylate-based dental resin composites Dipol® is examined through comprehensive kinetics research employing nanoindentation measurements and nanoscale atomic-deficient study with lifetime spectroscopy of annihilating positrons. Photopolymerization kinetics determined through nanoindentation testing is shown to be described via single-exponential relaxation function with character time constants reaching respectively 15.0 and 18.7 s for nanohardness and elastic modulus. Atomic-deficient characteristics of composites are extracted from positron lifetime spectra parameterized employing unconstrained x3-term fitting. The tested photopolymerization kinetics can be adequately reflected in time-dependent changes observed in average positron lifetime (with 17.9 s time constant) and fractional free volume of positronium traps (with 18.6 s time constant). This correlation proves that fragmentation of free-volume positronium-trapping sites accompanied by partial positronium-to-positron traps conversion determines the light-curing volumetric shrinkage in the studied composites.

Quantifying Asphalt Emulsion-Based Chip Seal Curing Times Using Electrical Resistance Measurements.

DOT National Transportation Integrated Search

2017-04-15

Chip sealing typically consists of covering a pavement surface with asphalt emulsion into which aggregate chips are embedded. The asphalt emulsion cures through the evaporation of water, thus providing mechanical strength to adhere to the pavement wh...

To evaluate the safety and efficacy of the TVT-Secur procedure in the treatment of stress urinary incontinence in women.

PubMed

Sandhu, J S; Karan, S C; Maiti, G D; Dudeja, Puja

2017-01-01

The prevalence of stress urinary incontinence (SUI) in the middle-aged Indian women is around 16%. The use of transvaginal tapes (TVTs) has revolutionised the surgical management of SUI. Patients who undergo placement of the tape via the transobturator route often complain of persistent thigh pain at the site of trocar insertion. The use of minimally invasive tapes with a single suburethral incision reduces surgical trauma by eliminating thigh incisions, while maintaining the cure achieved by conventional TVTs. The study was conducted to test the efficacy and safety of minimally invasive TVT-Secur tape placement for treatment of SUI in women. 20 women with stress incontinence were implanted with TVT-Secur tapes and followed up for a year. The objective cure rate of SUI was 85% at the end of a year. The improvement in the patient satisfaction and Incontinence-specific QOL scores, of both Urogenital Distress Inventory (UDI-6) and Incontinence Impact Questionnaire-7 (IIQ-7), was statistically significant at 95% and 99% confidence levels. There were no complaints of thigh pain; however, there were intraoperative complications in the form of bladder perforation in 5% ( n  = 1), urethral injury in 5% ( n  = 1) and urethral tape exposure in 10% ( n  = 2), at 3 months requiring tape sectioning. These cure rates and complications are comparable to the standard TVT implantations at the end of a year, without thigh pain; however, a greater number of patients and a longer follow-up is required to see whether the long-term cure is maintained or not, before recommending the same as a standard of treatment.

Ultrasonic Coating and Holographic Exposure Technology. Phase 1

DTIC Science & Technology

2015-09-01

introducing plaques to cure, which allowed the UV lamps to warm up. Temperature inside the UV oven could reach 35 °C if left on continuously. Curing time for...the deposition of thin films using an ultrasonic spray coater and patterning of the films using an ultraviolet ( UV ) laser. The main objectives for...required, and include such items as a corona discharge device, a UV curing oven, hot plate, and jigging for optics that were fabricated at Revision. Test

Light energy attenuation through orthodontic ceramic brackets at different irradiation times.

PubMed

Santini, Ario; Tiu, Szu Hui; McGuinness, Niall J P; Aldossary, Mohammed Saeed

2016-09-01

To evaluate the total light energy (TLE) transmission through three types of ceramic brackets with, bracket alone and with the addition of orthodontic adhesive, at different exposure durations, and to compare the microhardness of the cured adhesive. Three different makes of ceramic brackets, Pure Sapphire(M), Clarity™ ADVANCED(P) and Dual Ceramic(P) were used. Eighteen specimens of each make were prepared and allocated to three groups (n = 6). MARC(®)-resin calibrator was used to determine the light curing unit (LCU) tip irradiance (mW/cm(2)) and TLE (J/cm(2)) transmitted through the ceramic brackets, and through ceramic bracket plus Transbond™ XT Light Cure Adhesive, for 5, 10 and 20 s. Vickers-hardness values at the bottom of the cured adhesive were determined. Statistical analysis used one-way analysis of variance (ANOVA); P = 0.05. TLE transmission rose significantly among all samples with increasing exposure durations. TLE reaching the adhesive- enamel interface was less than 10 J/cm(2), and through monocrystalline and polycrystalline ceramic brackets was significantly different (P < 0.05). Pure Sapphire(M) showed the highest amount of TLE transmission and Vickers-hardness values for 5, 10 and 20 s. Following manufacturer's recommendations, insufficient TLE may be delivered to the adhesive: increasing the exposure durations may be required when adhesive is cured through ceramic brackets. Clinicians are advised to measure the tip irradiance of their LCUs and increase curing time beyond 5 s. Orthodontic clinicians should understand the type of light curing device and the orthodontic adhesive used in their practice.

Curing efficacy of a new generation high-power LED lamp.

PubMed

Yap, Adrian U J; Soh, M S

2005-01-01

This study investigated the curing efficacy of a new generation high-power LED lamp (Elipar Freelight 2 [N] 3M-ESPE). The effectiveness of composite cure with this new lamp was compared to conventional LED/halogen (Elipar Freelight [F], 3M-ESPE; Max [M], Dentsply-Caulk) and high-power halogen (Elipar Trilight [T], 3M-ESPE; Astralis 10 [A], Ivoclar Vivadent) lamps. Standard continuous (NS, FS, TS; MS), turbo (AT) and exponential (NE, FE, TE) curing modes of the various lights were examined. Curing efficacy of the various lights and modes were determined by measuring the top and bottom surface hardness of 2-mm thick composite specimens (Z100, 3M-ESPE) using a digital microhardness tester (n=5; load=500 g; dwell time=15 seconds) one hour after light polymerization. The hardness ratio was computed by dividing HK (Knoops Hardness) of the bottom surface by HK of the top surface. The data was analyzed using one-way ANOVA/Scheffe's test and Independent Samples t-test at significance level 0.05. Results of the statistical analysis were as follows: HK top--E, FE, NE > NS and NE > AT, TS, FS; HK bottom--TE, NE > NS; Hardness ratio--NS > FE and FS, TS > NE. No significant difference in HK bottom and hardness ratio was observed between the two modes of Freelight 2 and Max. Freelight 2 cured composites as effectively as conventional LED/halogen and high-power halogen lamps, even with a 50% reduction in cure time. The exponential modes of Freelight 2, Freelight and Trilight appear to be more effective than their respective standard modes.

Development of a fast curing tissue adhesive for meniscus tear repair.

PubMed

Bochyńska, Agnieszka Izabela; Hannink, Gerjon; Janssen, Dennis; Buma, Pieter; Grijpma, Dirk W

2017-01-01

Isocyanate-terminated adhesive amphiphilic block copolymers are attractive materials to treat meniscus tears due to their tuneable mechanical properties and good adhesive characteristics. However, a drawback of this class of materials is their relatively long curing time. In this study, we evaluate the use of an amine cross-linker and addition of catalysts as two strategies to accelerate the curing rates of a recently developed biodegradable reactive isocyanate-terminated hyper-branched adhesive block copolymer prepared from polyethylene glycol (PEG), trimethylene carbonate, citric acid and hexamethylene diisocyanate. The curing kinetics of the hyper-branched adhesive alone and in combination with different concentrations of spermidine solutions, and after addition of 2,2-dimorpholinodiethylether (DMDEE) or 1,4-diazabicyclo [2.2.2] octane (DABCO) were determined using FTIR. Additionally, lap-shear adhesion tests using all compositions at various time points were performed. The two most promising compositions of the fast curing adhesives were evaluated in a meniscus bucket handle lesion model and their performance was compared with that of fibrin glue. The results showed that addition of both spermidine and catalysts to the adhesive copolymer can accelerate the curing rate and that firm adhesion can already be achieved after 2 h. The adhesive strength to meniscus tissue of 3.2-3.7 N was considerably higher for the newly developed compositions than for fibrin glue (0.3 N). The proposed combination of an adhesive component and a cross-linking component or catalyst is a promising way to accelerate curing rates of isocyanate-terminated tissue adhesives.

Multiple imputation of missing covariates for the Cox proportional hazards cure model

PubMed Central

Beesley, Lauren J; Bartlett, Jonathan W; Wolf, Gregory T; Taylor, Jeremy M G

2016-01-01

We explore several approaches for imputing partially observed covariates when the outcome of interest is a censored event time and when there is an underlying subset of the population that will never experience the event of interest. We call these subjects “cured,” and we consider the case where the data are modeled using a Cox proportional hazards (CPH) mixture cure model. We study covariate imputation approaches using fully conditional specification (FCS). We derive the exact conditional distribution and suggest a sampling scheme for imputing partially observed covariates in the CPH cure model setting. We also propose several approximations to the exact distribution that are simpler and more convenient to use for imputation. A simulation study demonstrates that the proposed imputation approaches outperform existing imputation approaches for survival data without a cure fraction in terms of bias in estimating CPH cure model parameters. We apply our multiple imputation techniques to a study of patients with head and neck cancer. PMID:27439726

The application of cure models in the presence of competing risks: a tool for improved risk communication in population-based cancer patient survival.

PubMed

Eloranta, Sandra; Lambert, Paul C; Andersson, Therese M-L; Björkholm, Magnus; Dickman, Paul W

2014-09-01

Quantifying cancer patient survival from the perspective of cure is clinically relevant. However, most cure models estimate cure assuming no competing causes of death. We use a relative survival framework to demonstrate how flexible parametric cure models can be used in combination with competing-risks theory to incorporate noncancer deaths. Under a model that incorporates statistical cure, we present the probabilities that cancer patients (1) have died from their cancer, (2) have died from other causes, (3) will eventually die from their cancer, or (4) will eventually die from other causes, all as a function of time since diagnosis. We further demonstrate how conditional probabilities can be used to update the prognosis among survivors (eg, at 1 or 5 years after diagnosis) by summarizing the proportion of patients who will not die from their cancer. The proposed method is applied to Swedish population-based data for persons diagnosed with melanoma, colon cancer, or acute myeloid leukemia between 1973 and 2007.

Studies on chemoviscosity modeling for thermosetting resins

NASA Technical Reports Server (NTRS)

Bai, J. M.; Hou, T. H.; Tiwari, S. N.

1987-01-01

A new analytical model for simulating chemoviscosity of thermosetting resins has been formulated. The model is developed by modifying the well-established Williams-Landel-Ferry (WLF) theory in polymer rheology for thermoplastic materials. By introducing a relationship between the glass transition temperature Tg(t) and the degree of cure alpha(t) of the resin system under cure, the WLF theory can be modified to account for the factor of reaction time. Temperature dependent functions of the modified WLF theory constants C sub 1 (t) and C sub 2 (t) were determined from the isothermal cure data. Theoretical predictions of the model for the resin under dynamic heating cure cycles were shown to compare favorably with the experimental data. This work represents progress toward establishing a chemoviscosity model which is capable of not only describing viscosity profiles accurately under various cure cycles, but also correlating viscosity data to the changes of physical properties associated with the structural transformation of the thermosetting resin systems during cure.

Chemoviscosity modeling for thermosetting resin systems, part 3

NASA Technical Reports Server (NTRS)

Hou, T. H.; Bai, J. M.

1988-01-01

A new analytical model for simulating chemoviscosity resin has been formulated. The model is developed by modifying the well established Williams-Landel-Ferry (WLF) theory in polymer rheology for thermoplastic materials. By introducing a relationship between the glass transition temperature (T sub g (t)) and the degree of cure alpha(t) of the resin system under cure, the WLF theory can be modified to account for the factor of reaction time. Temperature-dependent functions of the modified WLF theory parameters C sub 1 (T) and C sub 2 (T) were determined from the isothermal cure data. Theoretical predictions of the model for the resin under dynamic heating cure cycles were shown to compare favorably with the experimental data. This work represents a progress toward establishing a chemoviscosity model which is capable of not only describing viscosity profiles accurately under various cure cycles, but also correlating viscosity data to the changes of physical properties associated with the structural transformations of the thermosetting resin systems during cure.

Electronic nose for the identification of pig feeding and ripening time in Iberian hams.

PubMed

Santos, J P; García, M; Aleixandre, M; Horrillo, M C; Gutiérrez, J; Sayago, I; Fernández, M J; Arés, L

2004-03-01

An electronic nose system to control the processing of dry-cured Iberian ham is presented. The sensors involved are tin oxide semiconductors thin films. They were prepared by RF sputtering. Some of the sensors were doped with metal catalysts as Pt and Pd, in order to improve the selectivity of the sensors. The multisensor with 16 semiconductor sensors, gave different responses from two types of dry-cured Iberian hams which differ in the feeding and curing time. The data has been analysed using the PCA (principal component analysis) and backpropagation and probabilistic neural networks. The analysis shows that different types of Iberian ham can be discriminated and identified successfully.

High performance printed oxide field-effect transistors processed using photonic curing.

PubMed

Garlapati, Suresh Kumar; Marques, Gabriel Cadilha; Gebauer, Julia Susanne; Dehm, Simone; Bruns, Michael; Winterer, Markus; Tahoori, Mehdi Baradaran; Aghassi-Hagmann, Jasmin; Hahn, Horst; Dasgupta, Subho

2018-06-08

Oxide semiconductors are highly promising candidates for the most awaited, next-generation electronics, namely, printed electronics. As a fabrication route for the solution-processed/printed oxide semiconductors, photonic curing is becoming increasingly popular, as compared to the conventional thermal curing method; the former offers numerous advantages over the latter, such as low process temperatures and short exposure time and thereby, high throughput compatibility. Here, using dissimilar photonic curing concepts (UV-visible light and UV-laser), we demonstrate facile fabrication of high performance In 2 O 3 field-effect transistors (FETs). Beside the processing related issues (temperature, time etc.), the other known limitation of oxide electronics is the lack of high performance p-type semiconductors, which can be bypassed using unipolar logics from high mobility n-type semiconductors alone. Interestingly, here we have found that our chosen distinct photonic curing methods can offer a large variation in threshold voltage, when they are fabricated from the same precursor ink. Consequently, both depletion and enhancement-mode devices have been achieved which can be used as the pull-up and pull-down transistors in unipolar inverters. The present device fabrication recipe demonstrates fast processing of low operation voltage, high performance FETs with large threshold voltage tunability.

A Study for the Characteristic Changes Under the Repeated Thermal Exposure in the Process of Repairing Aircraft Sandwich Structures

NASA Astrophysics Data System (ADS)

Kim, Yun Hae; Han, Joong Won; Kim, Don Won; Choi, Byung Keun; Murakami, R.

Delamination can be observed in the sound areas during and/or after a couple times exposure to the elevated curing temperature due to the repeated repair condition. This study was conducted for checking the degree of degradation of properties of the cured parts and delamination between skin prepreg and honeycomb core. Specimens with glass honeycomb sandwich construction and glass/epoxy prepreg were prepared. The specimens were cured 1 to 5 times at 260°F in an autoclave and each additionally exposed 50, 100 and 150 hours in the 260°F oven. Each specimen was tested for tensile strength, compressive strength, flatwise tensile strength and interlaminar shear strength. To monitor the characteristics of the resin itself, the cured resin was tested using DMA and DSC. As a results, the decrease of Tg value were observed in the specific specimen which is exposed over 50 hrs at 260°F. This means the change or degradative of resin properties is also related to the decrease of flatwise tensile properties. Accordingly, minimal exposure on the curing temperature is recommended for parts in order to prevent the delation and maintain the better condition.

Chemoviscosity modeling for thermosetting resins - I

NASA Technical Reports Server (NTRS)

Hou, T. H.

1984-01-01

A new analytical model for chemoviscosity variation during cure of thermosetting resins was developed. This model is derived by modifying the widely used WLF (Williams-Landel-Ferry) Theory in polymer rheology. Major assumptions involved are that the rate of reaction is diffusion controlled and is linearly inversely proportional to the viscosity of the medium over the entire cure cycle. The resultant first order nonlinear differential equation is solved numerically, and the model predictions compare favorably with experimental data of EPON 828/Agent U obtained on a Rheometrics System 4 Rheometer. The model describes chemoviscosity up to a range of six orders of magnitude under isothermal curing conditions. The extremely non-linear chemoviscosity profile for a dynamic heating cure cycle is predicted as well. The model is also shown to predict changes of glass transition temperature for the thermosetting resin during cure. The physical significance of this prediction is unclear at the present time, however, and further research is required. From the chemoviscosity simulation point of view, the technique of establishing an analytical model as described here is easily applied to any thermosetting resin. The model thus obtained is used in real-time process controls for fabricating composite materials.

High performance printed oxide field-effect transistors processed using photonic curing

NASA Astrophysics Data System (ADS)

Garlapati, Suresh Kumar; Cadilha Marques, Gabriel; Gebauer, Julia Susanne; Dehm, Simone; Bruns, Michael; Winterer, Markus; Baradaran Tahoori, Mehdi; Aghassi-Hagmann, Jasmin; Hahn, Horst; Dasgupta, Subho

2018-06-01

Oxide semiconductors are highly promising candidates for the most awaited, next-generation electronics, namely, printed electronics. As a fabrication route for the solution-processed/printed oxide semiconductors, photonic curing is becoming increasingly popular, as compared to the conventional thermal curing method; the former offers numerous advantages over the latter, such as low process temperatures and short exposure time and thereby, high throughput compatibility. Here, using dissimilar photonic curing concepts (UV–visible light and UV-laser), we demonstrate facile fabrication of high performance In2O3 field-effect transistors (FETs). Beside the processing related issues (temperature, time etc.), the other known limitation of oxide electronics is the lack of high performance p-type semiconductors, which can be bypassed using unipolar logics from high mobility n-type semiconductors alone. Interestingly, here we have found that our chosen distinct photonic curing methods can offer a large variation in threshold voltage, when they are fabricated from the same precursor ink. Consequently, both depletion and enhancement-mode devices have been achieved which can be used as the pull-up and pull-down transistors in unipolar inverters. The present device fabrication recipe demonstrates fast processing of low operation voltage, high performance FETs with large threshold voltage tunability.

Cast Stone Oxidation Front Evaluation: Preliminary Results For Samples Exposed To Moist Air

DOE Office of Scientific and Technical Information (OSTI.GOV)

Langton, C. A.; Almond, P. M.

The rate of oxidation is important to the long-term performance of reducing salt waste forms because the solubility of some contaminants, e.g., technetium, is a function of oxidation state. TcO{sub 4}{sup -} in the salt solution is reduced to Tc(IV) and has been shown to react with ingredients in the waste form to precipitate low solubility sulfide and/or oxide phases. Upon exposure to oxygen, the compounds containing Tc(IV) oxidize to the pertechnetate ion, Tc(VII)O{sub 4}{sup -}, which is very soluble. Consequently the rate of technetium oxidation front advancement into a monolith and the technetium leaching profile as a function ofmore » depth from an exposed surface are important to waste form performance and ground water concentration predictions. An approach for measuring contaminant oxidation rate (effective contaminant specific oxidation rate) based on leaching of select contaminants of concern is described in this report. In addition, the relationship between reduction capacity and contaminant oxidation is addressed. Chromate (Cr(VI) was used as a non-radioactive surrogate for pertechnetate, Tc(VII), in Cast Stone samples prepared with 5 M Simulant. Cast Stone spiked with pertechnetate was also prepared and tested. Depth discrete subsamples spiked with Cr were cut from Cast Stone exposed to Savannah River Site (SRS) outdoor ambient temperature fluctuations and moist air. Depth discrete subsamples spiked with Tc-99 were cut from Cast Stone exposed to laboratory ambient temperature fluctuations and moist air. Similar conditions are expected to be encountered in the Cast Stone curing container. The leachability of Cr and Tc-99 and the reduction capacities, measured by the Angus-Glasser method, were determined for each subsample as a function of depth from the exposed surface. The results obtained to date were focused on continued method development and are preliminary and apply to the sample composition and curing / exposure conditions described in this report. The Cr oxidation front (depth to which soluble Cr was detected) for the Cast Stone sample exposed for 68 days to ambient outdoor temperatures and humid air (total age of sample was 131 days) was determined to be about 35 mm below the top sample surface exposed. The Tc oxidation front, depth at which Tc was insoluble, was not determined. Interpretation of the results indicates that the oxidation front is at least 38 mm below the exposed surface. The sample used for this measurement was exposed to ambient laboratory conditions and humid air for 50 days. The total age of the sample was 98 days. Technetium appears to be more easily oxidized than Cr in the Cast Stone matrix. The oxidized forms of Tc and Cr are soluble and therefore leachable. Longer exposure times are required for both the Cr and Tc spiked samples to better interpret the rate of oxidation. Tc spiked subsamples need to be taken further from the exposed surface to better define and interpret the leachable Tc profile. Finally Tc(VII) reduction to Tc(IV) appears to occur relatively fast. Results demonstrated that about 95 percent of the Tc(VII) was reduced to Tc(IV) during the setting and very early stage setting for a Cast Stone sample cured 10 days. Additional testing at longer curing times is required to determine whether additional time is required to reduce 100 % of the Tc(VII) in Cast Stone or whether the Tc loading exceeded the ability of the waste form to reduce 100 % of the Tc(VII). Additional testing is required for samples cured for longer times. Depth discrete subsampling in a nitrogen glove box is also required to determine whether the 5 percent Tc extracted from the subsamples was the result of the sampling process which took place in air. Reduction capacity measurements (per the Angus-Glasser method) performed on depth discrete samples could not be correlated with the amount of chromium or technetium leached from the depth discrete subsamples or with the oxidation front inferred from soluble chromium and technetium (i.e., effective Cr and Tc oxidation fronts). Residual reduction capacity in the oxidized region of the test samples indicates that the remaining reduction capacity is not effective in re-reducing Cr(VI) or Tc(VII) in the presence of oxygen. Depth discrete sampling and leaching is a useful for evaluating Cast Stone and other chemically reducing waste forms containing ground granulated blast furnace slag (GGBFS) or other reduction / sequestration reagents to control redox sensitive contaminant chemistry and leachability in the near surface disposal environment. Based on results presented in this report, reduction capacity measured by the Angus-Glasser Ce(IV) method is not an appropriate or meaningful parameter for determining or predicting Tc and Cr oxidation / retentions, speciation, or solubilities in cementitious materials such as Cast Stone. A model for predicting Tc(IV) oxidation to soluble Tc(VII) should consider the waste form porosity (pathway for oxygen ingress), oxygen source, and the contaminant specific oxidation rates and oxidation fronts. Depth discrete sampling of materials exposed to realistic conditions in combination with short term leaching of crushed samples has potential for advancing the understanding of factors influencing performance. This information can be used to support conceptual model development.« less

Enhanced inhibition of Aspergillus niger on sedge (Lepironia articulata) treated with heat-cured lime oil.

PubMed

Matan, N; Matan, N; Ketsa, S

2013-08-01

This study aimed to examine heat curing effect (30-100°C) on antifungal activities of lime oil and its components (limonene, p-cymene, β-pinene and α-pinene) at concentrations ranging from 100 to 300 μl ml(-1) against Aspergillus niger in microbiological medium and to optimize heat curing of lime oil for efficient mould control on sedge (Lepironia articulata). Broth dilution method was employed to determine lime oil minimum inhibitory concentration, which was at 90 μl ml(-1) with heat curing at 70°C. Limonene, a main component of lime oil, was an agent responsible for temperature dependencies of lime oil activities observed. Response surface methodology was used to construct the mathematical model describing a time period of zero mould growth on sedge as functions of heat curing temperature and lime oil concentration. Heat curing of 90 μl ml(-1) lime oil at 70°C extended a period of zero mould growth on sedge to 18 weeks under moist conditions. Heat curing at 70°C best enhanced antifungal activity of lime oil against A. niger both in medium and on sedge. Heat curing of lime oil has potential to be used to enhance the antifungal safety of sedge products. © 2013 The Society for Applied Microbiology.

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.

Color Developing Capacity of Plasma-treated Water as a Source of Nitrite for Meat Curing.

PubMed

Jung, Samooel; Kim, Hyun Joo; Park, Sanghoo; Yong, Hae In; Choe, Jun Ho; Jeon, Hee-Joon; Choe, Wonho; Jo, Cheorun

2015-01-01

The interaction of plasma with liquid generates nitrogen species including nitrite (NO(-) 2). Therefore, the color developing capacity of plasma-treated water (PTW) as a nitrite source for meat curing was investigated in this study. PTW, which is generated by surface dielectric barrier discharge in air, and the increase of plasma treatment time resulted in increase of nitrite concentration in PTW. The PTW used in this study contains 46 ppm nitrite after plasma treatment for 30 min. To evaluate the effect of PTW on the cured meat color, meat batters were prepared under three different conditions (control, non-cured meat batter; PTW, meat batter cured with PTW; Sodium nitrite, meat batter cured with sodium nitrite). The meat batters were vacuum-packaged and cooked in a water-bath at 80℃ for 30 min. The typical color of cured meat developed in cooked meat batter treated with sodium nitrite or PTW. The lightness (L*) and yellowness (b*) values were similar in all conditions, whereas, the redness (a*) values of cooked meat batter with PTW and sodium nitrite (p<0.05) were significantly higher than the control. These data indicate that PTW can be used as a nitrite source in the curing process of meat without addition of other nitrite sources.

Color Developing Capacity of Plasma-treated Water as a Source of Nitrite for Meat Curing

PubMed Central

Jung, Samooel; Kim, Hyun Joo; Park, Sanghoo; Choe, Jun Ho; Jeon, Hee-Joon; Choe, Wonho

2015-01-01

The interaction of plasma with liquid generates nitrogen species including nitrite (NO−2). Therefore, the color developing capacity of plasma-treated water (PTW) as a nitrite source for meat curing was investigated in this study. PTW, which is generated by surface dielectric barrier discharge in air, and the increase of plasma treatment time resulted in increase of nitrite concentration in PTW. The PTW used in this study contains 46 ppm nitrite after plasma treatment for 30 min. To evaluate the effect of PTW on the cured meat color, meat batters were prepared under three different conditions (control, non-cured meat batter; PTW, meat batter cured with PTW; Sodium nitrite, meat batter cured with sodium nitrite). The meat batters were vacuum-packaged and cooked in a water-bath at 80℃ for 30 min. The typical color of cured meat developed in cooked meat batter treated with sodium nitrite or PTW. The lightness (L*) and yellowness (b*) values were similar in all conditions, whereas, the redness (a*) values of cooked meat batter with PTW and sodium nitrite (p<0.05) were significantly higher than the control. These data indicate that PTW can be used as a nitrite source in the curing process of meat without addition of other nitrite sources. PMID:26761900

Cure by age and stage at diagnosis for colorectal cancer patients in North West England, 1997-2004: a population-based study.

PubMed

Shack, L G; Shah, A; Lambert, P C; Rachet, B

2012-12-01

Stage and age at diagnosis are important prognostic factors for patients with colorectal cancer. However, the proportion cured by stage and age is unknown in England. This population-based study includes 29,563 adult patients who were diagnosed and registered with colorectal cancer during 1997-2004 and followed till 2007 in North West England. Multiple imputation was used to provide more reliable estimates of stage at diagnosis, when these data were missing. Cure mixture models were used to estimate the proportion 'cured' and the median survival of the uncured by age and stage. For both colon and rectal cancer the proportion of patients cured and median survival time of the uncured decreased with advancing stage and increasing age. Patients aged under 65 years had the highest proportion cured and longest median survival of the uncured. Cure of colorectal cancer patients is dependent on stage and age at diagnosis with younger patients or those with less advanced disease having a better prognosis. Further efforts are required, in order to reduce the proportion of patients presenting with stage III and IV disease and ultimately increase the chance of cure. Copyright © 2012 Elsevier Ltd. All rights reserved.

Survival analysis of patients with esophageal cancer using parametric cure model.

PubMed

Rasouli, Mahboube; Ghadimi, Mahmood Reza; Mahmoodi, Mahmood; Mohammad, Kazem; Zeraati, Hojjat; Hosseini, Mostafa

2011-01-01

Esophageal cancer is a major cause of mortality and morbidity in the Caspian littoral north-eastern part of Iran. The aim of this study was to calculate cure function as well as to identify the factors that are related to this function among patients with esophageal cancer in this geographical area. Three hundred fifty nine cases of esophageal cancer registered in the Babol cancer registry during the period of 1990 to 1991 (inclusive) were followed up for 15 years up to 2006. Parametric cure model was used to calculate cure fraction and investigate the factors responsible for probability of cure among patients. Sample of subjects encompassed 62.7% men and 37.3% women, with mean ages of diagnosis was 60.0 and 55.3 years, respectively. The median survival time reached about 9 months and estimated survival rates in 1, 3, and 5 years following diagnosis were 23%, 15% and 13%, respectively. Results show the family history affects the cured fraction independently of its effect on early outcome and has a significant effect on the probability of uncured. The average cure fraction was estimated to be 0.10. As the proportionality assumption of Cox model does not meet in certain circumstances, a parametric cure model can provide a better fit and a better description of survival related outcome.

Investigation of Test Methods, Material Properties, and Processes for Solar Cell Encapsulants

NASA Technical Reports Server (NTRS)

Willis, P. B.

1981-01-01

Encapsulant materials and processes for the production of cost effective, long life solar cell modules are identified, and evaluated. Ethylene vinyl acetate lamination pottant studies are conducted with respect to the time/temperature cure requirements for successful use of this compound. The time needed to produce successful gel contents are redetermined at a variety of temperatures and are related to the peroxide half life temperature curve. Formulation of the butyl acrylate syrup casting pottant is complete. The formulation contains an ultraviolet stabilizer system and is cured with an initiator that presents no shipping or handling hazards. The catalyzed syrup is stable at room temperature and has a pot life of at least an eight hour period of time. The syrup cures to a transparent rubber in 18 minutes at a temperature of 60 C.

Modeling the filament winding process

NASA Technical Reports Server (NTRS)

Calius, E. P.; Springer, G. S.

1985-01-01

A model is presented which can be used to determine the appropriate values of the process variables for filament winding a cylinder. The model provides the cylinder temperature, viscosity, degree of cure, fiber position and fiber tension as functions of position and time during the filament winding and subsequent cure, and the residual stresses and strains within the cylinder during and after the cure. A computer code was developed to obtain quantitative results. Sample results are given which illustrate the information that can be generated with this code.

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.

A combinaison of UV curing technology with ATL process

NASA Astrophysics Data System (ADS)

Balbzioui, I.; Hasiaoui, B.; Barbier, G.; L'hostis, G.; Laurent, F.; Ibrahim, A.; Durand, B.

2017-10-01

In order to reduce the time and the cost of manufacturing composite, UV curing technology combined with automated tape placement process (ATL) based on reverse approach by working with a fixed head was studied in this article. First, a brief description of the developed head placement is presented. Mechanical properties are then evaluated by varying process parameters, including compaction force and tape placement speed. Finally, a parametric study is carried out to identify suitable materials and process parameters to manufacture a photo composite material with high mechanical performances. The obtained results show that UV curing is a very good alternative for thermal polymerization because of its fast cure speed due to less dependency on temperature.

Exploration Of `Click' Chemistry For Microelectronic Applications

NASA Astrophysics Data System (ADS)

Musa, Osama M.; Sridhar, Laxmisha M.

The ‘Click’ chemistry was explored for low temperature snap cure and for possible use as an adhesion promoter in electronic applications. Several azide and alkyne resins were synthesized and their curing potential was evaluated with a special emphasis on exploring Cu(I) catalyst effect. The preliminary curing study in the absence of catalysts showed a strong dependence of cure temperatures on the electronic nature of alkynes. The cure temperatures showed a tendency to increase with decreasing electronegativity of the substituent on alkynes. The capability of Cu(I) catalysts to accelerate the ‘Click’ chemistry was demonstrated for the first time in bulk phase. Using several Cu(I) catalysts, the cure temperatures could be lowered by as much as 40-100°C compared to the control, depending on the nature of catalyst and the catalyst loading. We discovered a novel synergistic effect between Cu(I) and silver filler in lowering the cure temperatures. Using this combination, lower cure temperatures could be obtained than using either alone. Among several resins screened, one resin system has shown promise for 80°C snap-cure in which the aforementioned synergistic effect is operative. Solution phase ‘Click’ chemistry was employed for the synthesis of a hybrid triazole-epoxy resin system. This system was found to cure without added amine curative. The triazole group here serves as a linker as well as an internal adhesion promoter. To address the incompatibility and volatility issues, which arose during evaluation, a controlled oligomerization method has been developed using controlled heating of azides and alkynes in solution phase.

25 CFR 162.592 - What will BIA do if a lessee does not cure a violation of a WSR lease on time?

Code of Federal Regulations, 2013 CFR

2013-04-01

... 25 Indians 1 2013-04-01 2013-04-01 false What will BIA do if a lessee does not cure a violation of a WSR lease on time? 162.592 Section 162.592 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER LEASES AND PERMITS Wind and Solar Resource Leases Wsr Lease Effectiveness...

25 CFR 162.592 - What will BIA do if a lessee does not cure a violation of a WSR lease on time?

Code of Federal Regulations, 2014 CFR

2014-04-01

... 25 Indians 1 2014-04-01 2014-04-01 false What will BIA do if a lessee does not cure a violation of a WSR lease on time? 162.592 Section 162.592 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER LEASES AND PERMITS Wind and Solar Resource Leases Wsr Lease Effectiveness...

Classification of dry-cured hams according to the maturation time using near infrared spectra and artificial neural networks.

PubMed

Prevolnik, M; Andronikov, D; Žlender, B; Font-i-Furnols, M; Novič, M; Škorjanc, D; Čandek-Potokar, M

2014-01-01

An attempt to classify dry-cured hams according to the maturation time on the basis of near infrared (NIR) spectra was studied. The study comprised 128 samples of biceps femoris (BF) muscle from dry-cured hams matured for 10 (n=32), 12 (n=32), 14 (n=32) or 16 months (n=32). Samples were minced and scanned in the wavelength range from 400 to 2500 nm using spectrometer NIR System model 6500 (Silver Spring, MD, USA). Spectral data were used for i) splitting of samples into the training and test set using 2D Kohonen artificial neural networks (ANN) and for ii) construction of classification models using counter-propagation ANN (CP-ANN). Different models were tested, and the one selected was based on the lowest percentage of misclassified test samples (external validation). Overall correctness of the classification was 79.7%, which demonstrates practical relevance of using NIR spectroscopy and ANN for dry-cured ham processing control. Copyright © 2013 Elsevier Ltd. All rights reserved.

Determination of the viability of Toxoplasma gondii in cured ham using bioassay: influence of technological processing and food safety implications.

PubMed

Bayarri, Susana; Gracia, María J; Lázaro, Regina; Pe Rez-Arquillué, Consuelo; Barberán, Montserrat; Herrera, Antonio

2010-12-01

Toxoplasmosis is a zoonotic disease caused by the protozoan Toxoplasma gondii and distributed worldwide. Ingestion of viable cysts from infected raw or undercooked meat is an important route of horizontal transmission of the parasite to humans. Little information is available concerning the effect of commercial curing on cysts of T. gondii. This study is the first in which the influence of processing of cured ham on the viability of T. gondii has been evaluated, using bioassay to assess the risk of infection from eating this meat product. Naturally infected pigs were selected for the study, and a mouse concentration bioassay technique was used to demonstrate viable bradyzoites of T. gondii in porcine tissues and hams. No viable parasites were found in the final product (14 months of curing) based on results of the indirect immunofluorescence assay and histological and PCR analyses. Our results indicate that the consumption of hams cured as described here poses an insignificant risk of acquiring toxoplasmosis. However, additional studies are required to evaluate the safety of ham products cured under different conditions of curing time, salt, and nitrite concentration.

Monitoring the Cure State of Thermosetting Resins by Ultrasound.

PubMed

Lionetto, Francesca; Maffezzoli, Alfonso

2013-09-05

The propagation of low intensity ultrasound in a curing resin, acting as a high frequency oscillatory excitation, has been recently proposed as an ultrasonic dynamic mechanical analysis (UDMA) for cure monitoring. The technique measures sound velocity and attenuation, which are very sensitive to changes in the viscoelastic characteristics of the curing resin, since the velocity is related to the resin storage modulus and density, while the attenuation is related to the energy dissipation and scattering in the curing resin. The paper reviews the results obtained by the authors' research group in the last decade by means of in-house made ultrasonic set-ups for both contact and air-coupled ultrasonic experiments. The basics of the ultrasonic wave propagation in polymers and examples of measurements of the time-evolution of ultrasonic longitudinal modulus and chemical conversion of different thermosetting resins are presented. The effect of temperature on the cure kinetics, the comparison with rheological, low frequency dynamic mechanical and calorimetric results, and the correlation between ultrasonic modulus and crosslinking density will be also discussed. The paper highlights the reliability of ultrasonic wave propagation for monitoring the physical changes taking place during curing and the potential for online monitoring during polymer and polymer matrix composite processing.

Monitoring the Cure State of Thermosetting Resins by Ultrasound

PubMed Central

Lionetto, Francesca; Maffezzoli, Alfonso

2013-01-01

The propagation of low intensity ultrasound in a curing resin, acting as a high frequency oscillatory excitation, has been recently proposed as an ultrasonic dynamic mechanical analysis (UDMA) for cure monitoring. The technique measures sound velocity and attenuation, which are very sensitive to changes in the viscoelastic characteristics of the curing resin, since the velocity is related to the resin storage modulus and density, while the attenuation is related to the energy dissipation and scattering in the curing resin. The paper reviews the results obtained by the authors’ research group in the last decade by means of in-house made ultrasonic set-ups for both contact and air-coupled ultrasonic experiments. The basics of the ultrasonic wave propagation in polymers and examples of measurements of the time-evolution of ultrasonic longitudinal modulus and chemical conversion of different thermosetting resins are presented. The effect of temperature on the cure kinetics, the comparison with rheological, low frequency dynamic mechanical and calorimetric results, and the correlation between ultrasonic modulus and crosslinking density will be also discussed. The paper highlights the reliability of ultrasonic wave propagation for monitoring the physical changes taking place during curing and the potential for online monitoring during polymer and polymer matrix composite processing. PMID:28788306

Erratum to: Application of addition-cured silicone denture relining materials to adjust mouthguards.

PubMed

Fukasawa, Shintaro; Churei, Hiroshi; Chowdhury, Ruman Uddin; Shirako, Takahiro; Shahrin, Sharika; Shrestha, Abhishekhi; Wada, Takahiro; Uo, Motohiro; Takahashi, Hidekazu; Ueno, Toshiaki

2016-01-01

The purposes of this study were to examine the shock absorption capability of addition-cured silicone denture relining materials and the bonding strength of addition-cured silicone denture relining materials and a commercial mouthguard material to determine its applicability to mouthguard adjustment. Two addition-cured silicone denture relining materials were selected as test materials. The impact test was applied by a free-falling steel ball. On the other hand, bonding strength was determined by a delamination test. After prepared surface treatments using acrylic resin on MG sheet surface, 2 types of addition-cured silicone denture relining materials were glued to MG surface. The peak intensity, the time to peak intensity from the onset of the transmitted force and bonding strength were statistically analyzed using ANOVA and Tukey's honest significant difference post hoc test (p<0.05). These results suggest that the silicone denture relining materials could be clinically applicable as a mouthguard adjustment material.

Stress and flow analyses of ultraviolet-curable resin during curing

NASA Astrophysics Data System (ADS)

Umezaki, Eisaku; Okano, Akira; Koyama, Hiroto

2014-06-01

The stress and flow generated in ultraviolet (UV)-curable resin during curing in molds were measured to investigate their relationship. The specimens were molds consisting of glass plates and acrylic bars, and UV-curable liquid resin. The specimens were illuminated from above with UV rays. Photoelastic and visual images were separately obtained at a constant time interval using cameras during curing. To help obtain the visual images, acrylic powder was mixed with the liquid resin. The stress was obtained from the photoelastic images by a digital photoelastic technique with phase stepping, and the flow was obtained from the visual images by a particle-tracking velocimetry technique. Results indicate that the stress generated in the UV-curable resin during curing depends on the degree of contact between the mold and the cured area of the resin, and is hardly related to the flow.

Accelerated production of dry cured hams.

PubMed

Marriott, N G; Graham, P P; Shaffer, C K; Phelps, S K

1987-01-01

Ten uncured legs from the right side of the sampled pork carcasses (Study A) were vacuum tumbled with the cure adjuncts for 30 min (T) and 10 counterparts from the left side were tumbled 30 min, rested 30 min and tumbled an additional 30 min (TRT). Evaluations were conducted at 40 and 70 days after cure application for color, taste attributes, percentage moisture, percentage salt and NO(3)(-) and NO(2)(-) content. Study B was the same except that 18 legs were boned, tumbled and cured for 40, 56 and 70 days. The TRT samples (Study A) at 40 days sustained less color fading (P < 0.05) during cookery, but no differences (P > 0.05) existed among the uncooked hams. Increased cure time enhanced moisture loss and salt content (Study A) and color retention during cookery (Study B). The TRT samples had increased moisture loss and salt content (Study A). Copyright © 1987. Published by Elsevier Ltd.

Effect of Particular Breed on the Chemical Composition, Texture, Color, and Sensorial Characteristics of Dry-cured Ham

PubMed Central

Seong, Pil Nam; Park, Kuyng Mi; Kang, Sun Moon; Kang, Geun Ho; Cho, Soo Hyun; Park, Beom Young; Van Ba, Hoa

2014-01-01

The present study demonstrates the impact of specific breed on the characteristics of dry-cured ham. Eighty thighs from Korean native pig (KNP), crossbreed (Landrace×Yorkshire)♀×Duroc♂ (LYD), Berkshire (Ber), and Duroc (Du) pig breeds (n = 10 for each breed) were used for processing of dry-cured ham. The thighs were salted with 6% NaCl (w/w) and 100 ppm NaNO2, and total processing time was 413 days. The effects of breed on the physicochemical composition, texture, color and sensory characteristics were assessed on the biceps femoris muscle of the hams. The results revealed that the highest weight loss was found in the dry-cured ham of LYD breed and the lowest weight loss was found in Ber dry-cured ham. The KNP dry-cured ham contain higher intramuscular fat level than other breed hams (p<0.05). It was observed that the dry-cured ham made from KNP breed had the lowest water activity value and highest salt content, while the LYD dry-cure ham had higher total volatile basic nitrogen content than the Ber and Du hams (p<0.05). Zinc, iron and total monounsaturated fatty acids levels were higher in KNP ham while polyunsaturated fatty acids levels were higher in Du ham when compared to other breed hams (p<0.05). Additionally, the KNP dry-cured ham possessed higher Commission International de l’Eclairage (CIE) a* value, while the Du dry-cured ham had higher L*, CIE b* and hue angle values (p<0.05). Furthermore, breed significantly affected the sensory attributes of dry-cured hams with higher scores for color, aroma and taste found in KNP dry-cured ham as compared to other breed hams (p<0.05). The overall outcome of the study is that the breed has a potential effect on the specific chemical composition, texture, color and sensorial properties of dry-cured hams. These data could be useful for meat processors to select the suitable breeds for economical manufacturing of high quality dry-cured hams. PMID:25083111

Effect of Particular Breed on the Chemical Composition, Texture, Color, and Sensorial Characteristics of Dry-cured Ham.

PubMed

Seong, Pil Nam; Park, Kuyng Mi; Kang, Sun Moon; Kang, Geun Ho; Cho, Soo Hyun; Park, Beom Young; Van Ba, Hoa

2014-08-01

The present study demonstrates the impact of specific breed on the characteristics of dry-cured ham. Eighty thighs from Korean native pig (KNP), crossbreed (Landrace×Yorkshire)♀×Duroc♂ (LYD), Berkshire (Ber), and Duroc (Du) pig breeds (n = 10 for each breed) were used for processing of dry-cured ham. The thighs were salted with 6% NaCl (w/w) and 100 ppm NaNO2, and total processing time was 413 days. The effects of breed on the physicochemical composition, texture, color and sensory characteristics were assessed on the biceps femoris muscle of the hams. The results revealed that the highest weight loss was found in the dry-cured ham of LYD breed and the lowest weight loss was found in Ber dry-cured ham. The KNP dry-cured ham contain higher intramuscular fat level than other breed hams (p<0.05). It was observed that the dry-cured ham made from KNP breed had the lowest water activity value and highest salt content, while the LYD dry-cure ham had higher total volatile basic nitrogen content than the Ber and Du hams (p<0.05). Zinc, iron and total monounsaturated fatty acids levels were higher in KNP ham while polyunsaturated fatty acids levels were higher in Du ham when compared to other breed hams (p<0.05). Additionally, the KNP dry-cured ham possessed higher Commission International de l'Eclairage (CIE) a* value, while the Du dry-cured ham had higher L*, CIE b* and hue angle values (p<0.05). Furthermore, breed significantly affected the sensory attributes of dry-cured hams with higher scores for color, aroma and taste found in KNP dry-cured ham as compared to other breed hams (p<0.05). The overall outcome of the study is that the breed has a potential effect on the specific chemical composition, texture, color and sensorial properties of dry-cured hams. These data could be useful for meat processors to select the suitable breeds for economical manufacturing of high quality dry-cured hams.

A Phase 3, Multicenter, Randomized, Double-Blind, Vehicle-Controlled Study Evaluating the Safety and Efficacy of Metronidazole Vaginal Gel 1.3% in the Treatment of Bacterial Vaginosis.

PubMed

Schwebke, Jane R; Marrazzo, Jeanne; Beelen, Andrew P; Sobel, Jack D

2015-07-01

Bacterial vaginosis (BV), a prevalent infection in women of reproductive age, is associated with increased risk of upper genital tract and sexually transmitted infections, and complications in pregnancy. Currently approved treatments include metronidazole, which requires once or twice daily intravaginal administration for 5 days or twice daily oral administration for 7 days. This phase 3 study determined the safety and efficacy of single-dose metronidazole vaginal gel (MVG) 1.3%. In this double-blind, vehicle-controlled study, 651 women with clinical diagnosis of BV were randomized 1:1 to receive MVG 1.3% or vehicle vaginal gel. Primary efficacy measure was clinical cure (normal discharge, negative "whiff test," and <20% clue cells) at day 21. Secondary measures included therapeutic cure (both clinical and bacteriological; day 21) and bacteriologic cure (Nugent score <4), clinical cure, and time to resolution of symptoms (day 7). A total of 487 participants were included in the primary analysis. Clinical and therapeutic cure rates (day 21) were higher in participants treated with MVG 1.3% compared with vehicle gel (37.2% vs. 26.6% [P = 0.010] and 16.8% vs. 7.2% [P = 0.001], respectively). Clinical and bacteriologic cure rates (day 7) were also higher in the MVG 1.3% group (46.0% vs. 20.0% [P < 0.001] and 32.7% vs. 6.3% [P < 0.001], respectively). The median time to resolution of symptoms was shorter in the MVG 1.3% (day 6) than vehicle group (not reached). No serious adverse events were reported, and incidence was similar across treatment groups. Single-dose MVG 1.3% was safe and superior to vehicle gel in producing cure among women with BV.

Effect of polymerization method and fabrication method on occlusal vertical dimension and occlusal contacts of complete-arch prosthesis.

PubMed

Lima, Ana Paula Barbosa; Vitti, Rafael Pino; Amaral, Marina; Neves, Ana Christina Claro; da Silva Concilio, Lais Regiane

2018-04-01

This study evaluated the dimensional stability of a complete-arch prosthesis processed by conventional method in water bath or microwave energy and polymerized by two different curing cycles. Forty maxillary complete-arch prostheses were randomly divided into four groups (n = 10): MW1 - acrylic resin cured by one microwave cycle; MW2 - acrylic resin cured by two microwave cycles: WB1 - conventional acrylic resin polymerized using one curing cycle in a water bath; WB2 - conventional acrylic resin polymerized using two curing cycles in a water bath. For evaluation of dimensional stability, occlusal vertical dimension (OVD) and area of contact points were measured in two different measurement times: before and after the polymerization method. A digital caliper was used for OVD measurement. Occlusal contact registration strips were used between maxillary and mandibular dentures to measure the contact points. The images were measured using the software IpWin32, and the differences before and after the polymerization methods were calculated. The data were statistically analyzed using the one-way ANOVA and Tukey test (α = .05). he results demonstrated significant statistical differences for OVD between different measurement times for all groups. MW1 presented the highest OVD values, while WB2 had the lowest OVD values ( P <.05). No statistical differences were found for area of contact points among the groups ( P =.7150). The conventional acrylic resin polymerized using two curing cycles in a water bath led to less difference in OVD of complete-arch prosthesis.

Variable selection in a flexible parametric mixture cure model with interval-censored data.

PubMed

Scolas, Sylvie; El Ghouch, Anouar; Legrand, Catherine; Oulhaj, Abderrahim

2016-03-30

In standard survival analysis, it is generally assumed that every individual will experience someday the event of interest. However, this is not always the case, as some individuals may not be susceptible to this event. Also, in medical studies, it is frequent that patients come to scheduled interviews and that the time to the event is only known to occur between two visits. That is, the data are interval-censored with a cure fraction. Variable selection in such a setting is of outstanding interest. Covariates impacting the survival are not necessarily the same as those impacting the probability to experience the event. The objective of this paper is to develop a parametric but flexible statistical model to analyze data that are interval-censored and include a fraction of cured individuals when the number of potential covariates may be large. We use the parametric mixture cure model with an accelerated failure time regression model for the survival, along with the extended generalized gamma for the error term. To overcome the issue of non-stable and non-continuous variable selection procedures, we extend the adaptive LASSO to our model. By means of simulation studies, we show good performance of our method and discuss the behavior of estimates with varying cure and censoring proportion. Lastly, our proposed method is illustrated with a real dataset studying the time until conversion to mild cognitive impairment, a possible precursor of Alzheimer's disease. © 2015 The Authors. Statistics in Medicine Published by John Wiley & Sons Ltd.

Modeling the growth boundary of Listeria monocytogenes in ready-to-eat cooked meat products as a function of the product salt, moisture, potassium lactate, and sodium diacetate concentrations.

PubMed

Legan, J D; Seman, D L; Milkowski, A L; Hirschey, J A; Vandeven, M H

2004-10-01

A central composite response surface design was used to determine the time to growth of Listeria monocytogenes as a function of four continuous variables: added sodium chloride (0.8 to 3.6%), sodium diacetate (0 to 0.2%), potassium lactate syrup (60% [wt/wt]; 0.25 to 9.25%), and finished-product moisture (45.5 to 83.5%) in ready-to-eat cured meat products. The design was repeated for ready-to-eat uncured meat products giving a fifth categorical variable for cure status. Products were stored at 4 degrees C. The results were modeled using a generalized regression approach. All five main effects, six two-factor interactions, and two quadratic terms were statistically significant. The model was used to show the boundary between growth and no-growth conditions at 4 degrees C using contour plots of time to growth. It was validated using independent challenge studies of cured and uncured products. Generally, the model predicted well, particularly for cured products, where it will be useful for establishing conditions that prevent the growth of L. monocytogenes. For uncured products, there was good agreement overall between predicted and observed times to growth, but the model is less thoroughly validated than for cured products. The model should initially only be used for screening of formulations likely to prevent growth of Listeria monocytogenes in uncured products, with recommendations subject to confirmation by challenge studies.

Acoustic Monitoring of Adhesive Bond Curing in Wood Laminates.

NASA Astrophysics Data System (ADS)

Biernacki, Jacek Marek

Challenges in manufacturing of wood products, such as glulam, include difficulty in controlling bonding variables and assessing bond quality. This dissertation investigates an ultrasonic method as a means of monitoring of curing and assessing bond quality in wood laminates. The effect of curing on ultrasonic transmission was studied using specimens of clear Douglas-fir, 100 x 200 x 600 mm, with the adhesive bond in the center of the specimen. Monitoring was performed simultaneously at normal and angular (5 ^circ nominal) incidence to the bond plane. Acoustic measurements were supplemented with destructive cure monitoring, standard bond strength measurement, monitoring of bulk viscosity curing, gel time measurement, and microscopic (SEM) examination. Angular incidence gave greater sensitivity to bond quality and curing status than did normal incidence. Analysis of wave propagation showed that displacement for transmission at a small angle (on the order of 5^circ ) was nearly parallel to the bond, which seems to explain greater sensitivity of angular incidence. Experimental results showed that this method was effective in detection of curing phases, such as spread, penetration, and hardening, defective bonds, and the effect of clamping pressure. An "unloading effect", measured as a relative transmission reduction after the clamping load was released, was sensitive to defective bonds, including uncured (kissing), underspread, and uneven spread bonds. Thick bonds (0.5 and 1.0 mm) caused the greatest increase in transmission, since waves at start of curing were highly attenuated. In angular transmission, thick-bond curing curves showed a characteristic inflection, which may be used to identify thick bonds and measure the curing rate. The results of this dissertation could be utilized to develop commercial systems in glulam manufacturing, which could evaluate: (a) phase of and completion of curing (b) bond quality (c) optimum clamping pressure. Similar systems could also be developed to monitor lumber and panel products curing at high temperature, such as LVL (laminated veneer lumber), OSB (oriented strandboard) and particleboard.

Cure of Psoriasis and Arthritis when Addison's Disease Was Detected

PubMed Central

Lind, Marcus

2010-01-01

Introduction Corticoid therapy is well-known to improve the symptoms of psoriasis. Addison's disease is an autoimmune disease which leads to a loss of cortisol production in the adrenal glands. This case report describes a patient with wide-spread psoriasis for 34 years who was cured when Addison's disease was detected and substitution to reach normal biological cortisol levels was introduced. Case Report A 59-year-old man was diagnosed with Addison's disease. He had been tired for several years and had had difficulties in continuing his work. His brother had Addison's disease and recommended him to make a screen for the disease. Synacthen test diagnosed Addison's disease with a clear deficiency of cortisol production. After substitution with hydrocortisone the patient's constitution improved rapidly and he felt no longer tired during work. At the same time, all skin lesions of psoriasis disappeared as well as aches in several joints, both symptoms having been present for a couple of decades. Previously, salves of cortisol had been used to reduce the symptoms of psoriasis, but now, 1–2 years later, after the treatment of Addison's disease, no symptoms in the skin or joints have reoccurred. Conclusions This report illustrates that Addison's disease, although a rare condition, should be kept in mind before treatment of psoriasis is started. Especially if other symptoms such as fatigue are present, a screening test of serum cortisol in the morning should be liberally made. The report also illustrates a need of examining corticoid levels in patients with psoriasis compared to the general population. PMID:21103194

Cure of Psoriasis and Arthritis when Addison's Disease Was Detected.

PubMed

Lind, Marcus

2010-06-01

INTRODUCTION: Corticoid therapy is well-known to improve the symptoms of psoriasis. Addison's disease is an autoimmune disease which leads to a loss of cortisol production in the adrenal glands. This case report describes a patient with wide-spread psoriasis for 34 years who was cured when Addison's disease was detected and substitution to reach normal biological cortisol levels was introduced. CASE REPORT: A 59-year-old man was diagnosed with Addison's disease. He had been tired for several years and had had difficulties in continuing his work. His brother had Addison's disease and recommended him to make a screen for the disease. Synacthen test diagnosed Addison's disease with a clear deficiency of cortisol production. After substitution with hydrocortisone the patient's constitution improved rapidly and he felt no longer tired during work. At the same time, all skin lesions of psoriasis disappeared as well as aches in several joints, both symptoms having been present for a couple of decades. Previously, salves of cortisol had been used to reduce the symptoms of psoriasis, but now, 1-2 years later, after the treatment of Addison's disease, no symptoms in the skin or joints have reoccurred. CONCLUSIONS: This report illustrates that Addison's disease, although a rare condition, should be kept in mind before treatment of psoriasis is started. Especially if other symptoms such as fatigue are present, a screening test of serum cortisol in the morning should be liberally made. The report also illustrates a need of examining corticoid levels in patients with psoriasis compared to the general population.

Effects of blood contamination on resin-resin bond strength.

PubMed

Eiriksson, Sigurdur O; Pereira, Patricia N R; Swift, Edward J; Heymann, Harald O; Sigurdsson, Asgeir

2004-02-01

Incremental placement and curing of resin composites has been recommended. However, this requires longer operating time, and therefore, increased risk of contamination. The purpose of this study was to evaluate the effects of blood contamination on microtensile bond strengths (microTBS) between resin interfaces and to determine the best decontamination method to re-establish the original resin-resin bond strength. The top surfaces of 64, 4-mm composite blocks (Z-250, Renew, APX, Pertac II) were untreated as the control, or were treated as follows: blood applied and dried on the surface (Treatment 1), blood applied, rinsed, dried (Treatment 2), blood applied, rinsed, and an adhesive applied (Single Bond, One-Step, Clearfil SE, Prompt L-Pop) (Treatment 3). Fresh composite was applied and light-cured in 2-mm increments. After 24 h storage in water, the specimens were sectioned into 0.7-mm thick slabs, trimmed to a cross-sectional area of 1 mm(2), and loaded to failure at a crosshead speed of 1 mm/min using an Instron universal testing machine. Data were analyzed using two-way ANOVA and Fisher's PLSD test (p<0.05). Control values ranged from 45.1 MPa for Pertac II to 71.5 MPa for APX. Untreated blood contamination resulted in resin-resin bond strengths of only 1.0-13.1 MPa. Rinsing raised bond strengths to over 40 MPa for each material. Use of an adhesive further increased bond strengths except for Pertac II. Rinsing blood from contaminated surfaces increases the resin-resin bond strength significantly and the application of an appropriate adhesive increases the bond strength to control levels.

A minimum version of log-rank test for testing the existence of cancer cure using relative survival data.

PubMed

Yu, Binbing

2012-01-01

Cancer survival is one of the most important measures to evaluate the effectiveness of treatment and early diagnosis. The ultimate goal of cancer research and patient care is the cure of cancer. As cancer treatments progress, cure becomes a reality for many cancers if patients are diagnosed early and get effective treatment. If a cure does exist for a certain type of cancer, it is useful to estimate the time of cure. For cancers that impose excess risk of mortality, it is informative to understand the difference in survival between cancer patients and the general cancer-free population. In population-based cancer survival studies, relative survival is the standard measure of excess mortality due to cancer. Cure is achieved when the survival of cancer patients is equivalent to that of the general population. This definition of cure is usually called the statistical cure, which is an important measure of burden due to cancer. In this paper, a minimum version of the log-rank test is proposed to test the equivalence of cancer patients' survival using the relative survival data. Performance of the proposed test is evaluated by simulation. Relative survival data from population-based cancer registries in SEER Program are used to examine patients' survival after diagnosis for various major cancer sites. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Cost of Biological Terrorism.

PubMed

Coffey

1997-01-01

Most Americans are or will be facing a threat more real than crimes or terrorism-it is the threat of cancer. Indeed, one-fourth of all Americans alive today will ultimately die from cancer. Yet the level of funding for cancer research in 1998 and beyond remains in doubt. The Senate Appropriations Committee has proposed a higher funding figure than the House and the difference will be resolved in negotiations this September. President Clinton has recommended a meager 2.5% increase in spending on cancer. This sum is simply not enough. Although Americans may fool themselves into thinking the government has been at war against cancer, the current funding ceiling for the National Institutes of Health (NIH) budget demonstrates that this so-called offensive is little more than a skirmish. Careful scrutiny of this budget reveals that every time a citizen pays ten dollars in taxes, only one penny goes to cancer research. What the government is spending in cancer research would not buy or maintain two stealth bombers-hardly evidence of a major military strike. For those of us fighting the deadly scourge of cancer, the 1,550 Americans killed each day by this disease are painful and enduring casualties. Imagine five fully loaded jumbo jets crashing with no survivors on the same day. These headlines would generate fast and effective calls for funding for improved safety regulations, and yet cancer takes this number of lives daily-and in one year more lives than all the U.S. combat fatalities in this century. And yet there is a virtual silence as Congress meets to determine the level of monies to direct to cancer research efforts which might halt this carnage. In the past, medical research stopped the horrors of pain associated with amputations and operations conducted without anesthesia, and research stopped the epidemic of polio and the massive deaths from typhoid fever. Soon research will stop the deaths from AIDS. Will cancer be prevented or cured within your lifetime? It should and can be, but only if Americans speak up and demand Congress do its part to advance promising research by supporting NIH and efforts to control cancer. Cancer has stricken almost every family and we urgently need more defense. We must not sit waiting quietly any longer. It is time for a wake-up call to arms, to declare a war effort that demands results. The U.S. paid thirty times more for the Gulf War than the annual budget allotment for cancer research, and five times more to maintain the space program. Today, three-fourths of all cancer research grants approved by critical scientific review still go inactive. These instances represent more lost opportunities, more lost time, more lost lives. We must do better than this. Cancer strikes at the heart and fabric of our society. For the 1.3 million Americans diagnosed with cancer this year, the cost to our economy will exceed $100 billion. Thus, the $2.4 billion now being spent on research is insufficient medically and morally. Several clear-sighted congressional leaders who understand the critical need for increased funding have worked to assure expanded resources for the NIH and for cancer research. Unfortunately, their voices are too often drowned out by legislators with different agendas. Even with limited funds, America's past 25 years of cancer research has paid off. We have already cured some types of cancers, especially those that strike our young people. From 1973 to 1990, the cancer death rate from birth to 19 years of age decreased 38%; from 20 to 40 years, 20%; and from 45 to 54 years, 10%. Over this same period, the government invested $56 million on testicular cancer research. This effort yielded a 91% cure rate and produced an annual savings of $166 million that will last forever. The financial investment was repaid in six months, and the victims have an increased life expectancy of 40 years. These examples and others are proof of the principle that the support of cancer research pays off. However, we have not yet won such hard-fought victories on the more prevalent forms of cancers such as breast, prostate, and lung. Whether it is by cure or prevention, cancers must also be controlled and it can only be accomplished through research. On December 23, 1971, President Richard Nixon signed the National Cancer Act that was to provide, ".a total commitment of Congress and the president. to provide the funds. for the conquest of cancer." Somewhere this contract with America got lost. We are now faced with more losses. The new upheaval in American medicine threatens clinical research in cancer investigation to test new therapies and to support the training of new research soldiers to join the battle. The bottom-line approach of insurance and managed care policies no longer cares about these essential components; they say it is no longer their responsibility. This loss of financial support, combined with the tepid endorsement of funding of research from the government, occurs just when there is an explosion of new discoveries and opportunities becoming available to attack cancer. It is time to dramatically increase our efforts and no time to retreat. If we really want to defend against the terrorism of cancer, we need to attack it with a real war effort. If we can go to Mars, we can go to war on cancer, but only if Americans can speak louder than their elected government leaders. They need to hear our opinion, now.

Investigation of Coatings Which Prevent Molten Aluminum/Water Explosions

NASA Astrophysics Data System (ADS)

León, D. D.; Richter, R. T.; Levendusky, T. L.

The Aluminum Association contracted Alcoa in 1995 to identify and test new protective coatings for casting pits as a replacement for Porter International's 7001 (Tarset Standard). Three new coatings have been identified through a series of selection criteria including: 1) A standardized splash test used to evaluate personal protective clothing, 2) An industry-standard molten metal explosion test, 3) A multiple-exposure test to measure durability, and 4) An external shock impact test. The results of this program will be reviewed. This study only tested protective coatings at the "in-service cure time", as defined by the manufacturer. These curing times can be excessive for a production casting facility. The Aluminum Association has contracted Alcoa in a second program to investigate the effect of reduced cure times on adhesion and their effectiveness in preventing molten metal/water explosions. A status update of this new two year program is provided.

Investigation of test methods, material properties, and processes for solar cell encapsulants

NASA Technical Reports Server (NTRS)

Willis, P. B.

1982-01-01

Technical investigations concerned the development of advanced cure chemistries for lamination type pottants; the continued evaluation of soil resistant surface treatments, and the results of an accelerated aging test program for the comparison of material stabilities. New compounds were evaluated for efficiency in curing both ethylene/vinyl acetate and ethylene/methyl acrylate pottants intended for vacuum bag lamination of solar cells. One compound in particular, designated Lupersol - TBEC (Lucidol Division of Pennwalt Corp.) was found to be unusually effective in promoting the rapid cure of both these materials. Formulation of these resins with TBEC resulted in compositions of very high gel content, lower temperatures of activation, and much lower cure times, even in the ethylene/methyl acrylate polymer that is more difficult to cure. It is expected that TBEC modified pottant formulations may permit the lamination/encapsulation step to be operated at lower temperatures, higher speed, higher throughput and a much wider tolerance for intentional or accidental variations in the cure schedule. An experimental program continued to determine the effectiveness of soil resistant coatings.

Monitoring cure properties of out-of-autoclave BMI composites using IFPI sensor

NASA Astrophysics Data System (ADS)

Kaur, Amardeep; Anandan, Sudharshan; Yuan, Lei; Watkins, Steve E.; Chandrashekhara, K.; Xiao, Hai; Phan, Nam

2016-04-01

A non-destructive technique for inspection of a Bismaleimide (BMI) composite is presented using an optical fiber sensor. High performance BMI composites are used for Aerospace application for their mechanical strength. They are also used as an alternative to toughened epoxy resins. A femtosecond-laser-inscribed Intrinsic Fabry-Perot Interferometer (IFPI) sensor is used to perform real time cure monitoring of a BMI composite. The composite is cured using the out-of-autoclave (OOA) process. The IFPI sensor was used for in-situ monitoring; different curing stages are analyzed throughout the curing process. Temperature-induced-strain was measured to analyze the cure properties. The IFPI structure comprises of two reflecting mirrors inscribed on the core of the fiber using a femtosecond-laser manufacturing process. The manufacturing process makes the sensor thermally stable and robust for embedded applications. The sensor can withstand very high temperatures of up to 850 °C. The temperature and strain sensitivities of embedded IFPI sensor were measured to be 1.4 pm/μepsilon and 0.6 pm/μepsilon respectively.

Monitoring Fiber Stress During Curing of Single Fiber Glass- and Graphite-Epoxy Composites

NASA Technical Reports Server (NTRS)

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

1994-01-01

The difference in thermal expansion characteristics of epoxy matrices and graphite fibers can produce significant residual stresses in the fibers during curing of composite materials. Tests on single fiber glass-epoxy and graphite-epoxy composite specimens were conducted in which the glass and graphite fibers were preloaded in tension, and the epoxy matrix was cast around the fibers. The fiber tension was monitored while the matrix was placed around the fiber and subjected to the temperature-time curing cycle. Two mechanisms responsible for producing stress in embedded fibers were identified as matrix thermal expansion and contraction and matrix cure shrinkage. A simple analysis based on the change in fiber tension during the curing cycle was conducted to estimate the produced stresses. Experimental results on single fiber glass- and graphite-epoxy composites show that the fiber was subjected to significant tensile stresses when the temperature was raised from the first to the second dwell period. When initial fiber pretension is about 60 percent of the fiber failure load, these curing-induced stresses can cause tensile fracture of the embedded fiber.

Efficiency of dual-cured resin cement polymerization induced by high-intensity LED curing units through ceramic material.

PubMed

Watanabe, H; Kazama, Re; Asai, T; Kanaya, F; Ishizaki, H; Fukushima, M; Okiji, T

2015-01-01

This study aimed to evaluate the ability of high-intensity light-emitting diode (LED) and other curing units to cure dual-cured resin cement through ceramic material. A halogen curing unit (Jetlite 3000, Morita), a second-generation LED curing unit (Demi, Kerr), and two high-intensity LED curing units (PenCure 2000, Morita; Valo, Ultradent) were tested. Feldspathic ceramic plates (VITABLOCS Mark II, A3; Vita Zahnfabrik) with thicknesses of 1.0, 2.0, and 3.0 mm were prepared. Dual-cured resin cement samples (Clearfil Esthetic Cement, Kuraray Noritake Dental) were irradiated directly or through one of the ceramic plates for different periods (5, 10, 15, or 20 seconds for the high-intensity LED units and 20, 40, 60, or 80 seconds for the others). The Knoop hardness test was used to determine the level of photopolymerization that had been induced in the resin cement. Data were analyzed by one-way analysis of variance and Dunnett's post-hoc test to identify test-control (maximum irradiation without a ceramic plate) differences for each curing unit (p<0.05). For all curing units, the curing conditions had a statistically significant effect on the Knoop hardness numbers (KHNs) of the irradiated cement samples (p<0.001). In general, the KHN decreased with increasing plate thickness and increased as the irradiation period was extended. Jetlite 3000 achieved control-level KHN values only when the plate thickness was 1.0 mm. At a plate thickness ≥2.0 mm, the LED units (except for PenCure 2000 at 3.0 mm) were able to achieve control-level KHN values when the irradiation time was extended. At a plate thickness of 3.0 mm, irradiation for 20 seconds with the Valo or for 80 seconds with the Demi were the only methods that produced KHN values equivalent to those produced by direct irradiation. Regardless of the type of curing unit used, indirect irradiation of dual-cured resin cement through a ceramic plate resulted in decreased KHN values compared with direct irradiation. When the irradiation period was extended, only the LED units were able to achieve similar KHN values to those observed under direct irradiation in the presence of plates ≥2.0-mm thick. High-intensity LED units require a shorter irradiation period than halogen and second-generation LED curing units to obtain KHN values similar to those observed during direct irradiation.

Towards multi-disciplinary HIV cure research: integrating social science with biomedical research

PubMed Central

Grossman, Cynthia I; Ross, Anna Laura; Auerbach, Judith D.; Ananworanich, Jintanat; Dubé, Karine; Tucker, Joseph D.; Noseda, Veronica; Possas, Cristina; Rausch, Dianne

2015-01-01

The quest for a cure for HIV remains a timely and key challenge for the HIV research community. Despite significant scientific advances, current HIV therapy regimens do not completely eliminate the negative impact of HIV on the immune system; and the economic impact of treating all people infected with HIV globally, for the duration of their lifetimes, presents significant challenges. This article discusses, from a multi-disciplinary approach, critical social, behavioral, ethical, and economic issues permeating the HIV cure research agenda. As part of a search for an HIV cure, both the perspective of patients/participants and clinical researchers should be taken into account. In addition, continued efforts should be made to involve and educate the broader community. PMID:26642901

Towards Multidisciplinary HIV-Cure Research: Integrating Social Science with Biomedical Research.

PubMed

Grossman, Cynthia I; Ross, Anna Laura; Auerbach, Judith D; Ananworanich, Jintanat; Dubé, Karine; Tucker, Joseph D; Noseda, Veronica; Possas, Cristina; Rausch, Dianne M

2016-01-01

The quest for a cure for HIV remains a timely and key challenge for the HIV research community. Despite significant scientific advances, current HIV therapy regimens do not completely eliminate the negative impact of HIV on the immune system; and the economic impact of treating all people infected with HIV globally, for the duration of their lifetimes, presents significant challenges. This article discusses, from a multidisciplinary approach, critical social, behavioral, ethical, and economic issues permeating the HIV-cure research agenda. As part of a search for an HIV cure, both the perspective of patients/participants and clinical researchers should be taken into account. In addition, continued efforts should be made to involve and educate the broader community. Published by Elsevier Ltd.

Influence of curing times on the effectiveness of treatments with acetic acid on the control of P. digitatum on lemons.

PubMed

Venditti, T; D'Hallewin, G; Dore, A; Molinu, M G

2011-01-01

The restricted number of postharvest fungicides used in packing houses is leading to the selection of resistant strains of Penicillium digitatum (citrus green mould), one of the most common and serious pathogens during storage and marketing of lemons. Furthermore a growing concern for human health and a greater awareness for environmental conservation have multiplied the studies on new ecological technologies. Among the alternatives to synthetic postharvest fungicides, the use of acetic acid (classified as GRAS) together with a physical method such as curing, have led to encouraging results. In the present study is reported the combined use of curing, performed at reduced times compared to those reported to be effective, followed by acetic acid (AAC) treatments. Lemons of the variety "Limone di Massa" artificially inoculated with P. digitatum at a concentration of 10(4) spores/mL were cured for 0, 3, 6, 12 and 24 hours and then treated with three different concentrations of AAC (25, 50 and 75 microL/L) for 15 min. Fruit was then stored at 20 degrees C and 80% relative humidity (RH) for 9 days, when the number of decayed fruits was monitored. The same combined treatments were also carried out on naturally infected lemons, stored for 6 or 8 weeks at 5 degrees C and 90% RH. After 9 days of storage the lowest percentage of infected wounds, in artificially inoculated fruit, was 0% after 6 hours of curing followed by AAC fumigation performed at 50 microL/L, while lemons untreated or cured for three hours showed the worst results with 71.4 and 61.9% of rotted fruit respectively. In naturally infected lemons the best results were achieved with curing performed for 24 hours followed by AAC fumigation at 50 microL/L. In these cases the combined treatment reduced decay by the 91.0 and 66.5% after 6 or 8 weeks of storage respectively, if compared to untreated fruit. The weight loss was not affected by any of the treatments. These results show that a good control of green mould during storage could be achieved, on lemon fruit, by combining a reduced curing time of 24 hours to the effect of AAC. The best results were obtained after 6 week of storage even if a satisfactory control was observed after 8 weeks of storage.

Effect of Shade and Light Curing Mode on the Degree of Conversion of Silorane-Based and Methacrylate-Based Resin Composites.

PubMed

Sm, Mousavinasab; M, Atai; N, Salehi; A, Salehi

2016-12-01

The degree of conversion depends on the material composition, light source properties, distance from light source, light intensity, curing time, and other factors such as shade and translucency. In the present study, we evaluated the effects of different light-curing modes and shades of methacrylate and silorane-based resin composites on the degree of conversion of resin composites (DC). The methacrylate-based (Filtek Z250, 3M, ESPE) and low-shrinkage silorane-based (Filtek P90, 3M, ESPE) resin composites were used in three groups as follows: group 1-Filtek Z250 (shade A3), group 2-Filtek Z250 (shade B2), and group 3-Filtek P90 (shade A3). We used a light-emitting diode (LED) curing unit for photopolymerization. 10 samples were prepared in each group to evaluate the degree of conversion; 5 samples were cured using soft-start curing mode, and the other 5 were cured using standard curing mode. The DC of the resin composites was measured using Fourier Transform Infrared Spectroscopy (FTIR). The data were analyzed using Kruskal Wallis and one-way ANOVA statistical tests. The degree of conversion of silorane-based resin composite was 70 - 75.8% and that of methacrylate-based resin composites was 60.2 - 68.2% (p = 0.009). The degree of conversion of the composite with brighter colour (B2) was statistically more than the darker composite (A3). Higher degree of conversion was achieved applying the standard curing mode. The results of the study showed that the colour and type of the resin composite and also the curing mode influence the degree of conversion of resin composites.

Polymerization kinetics of experimental bioactive composites containing bioactive glass.

PubMed

Par, Matej; Tarle, Zrinka; Hickel, Reinhard; Ilie, Nicoleta

2018-06-21

To investigate the polymerization kinetics and the degree of conversion (DC) of experimental resin composites with varying amount of bioactive glass 45S5 (BG). Experimental resin composites based on a photo-curable Bis-GMA/TEGDMA resin system were prepared. The composite series contained 0, 5, 10, 20, and 40 wt% of BG and reinforcing fillers up to the total filler amount of 70 wt%. Composite specimens were light cured with 1,219 mW/cm 2 for 20 or 40 s and their DC was monitored during 5 min at the data collection rate of 2 s -1 using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). The 5-min DC values for experimental composites were in the range of 42.4-55.9% and 47.3-57.9% for curing times of 20 and 40 s, respectively. The differences in the 5-min DC between curing times of 20 s or 40 s became more pronounced in materials with higher BG amount. Within both curing times, a decreasing trend of the 5-min DC values was observed with the increasing percentage of BG fillers. The maximum polymerization rate also decreased consistently with the increasing BG amount. Unsilanized BG fillers showed a dose-dependent inhibitory effect on polymerization rate and the DC. Extending the curing time from 20 to 40 s showed a limited potential to improve the DC of composites with higher BG amount. The observed inhibitory effect of BG fillers on the polymerization of resin composites may have a negative influence on mechanical properties and biocompatibility. Copyright © 2018. Published by Elsevier Ltd.

Effect of prior refrigeration on botulinal outgrowth in perishable canned cured meat when temperature abused.

PubMed Central

Tompkin, R B; Christiansen, L N; Shaparis, A B

1978-01-01

Perishable canned cured meat inoculated with Clostridium botulinum spores was placed at 4.4 or 10 degrees C after manufacture. Spore germination occurred at 10 degrees C. The germinated cell count remained stable over a period of 16 to 18 weeks. During that time period the inhibitory system and residual nitrite descreased. These factors combine to make perishable canned cured meats more prone to spoilage and potential hazard if they are temperature abused after a period of refrigerated storage. PMID:350155

Effects of recording time and residue on dose-response by LiMgPO4: Tb, B ceramic disc synthesized via improved sintering process

NASA Astrophysics Data System (ADS)

Kong, Xirui; Fu, Zhilong; Que, Huiying; Fan, Yanwei; Chen, Zhaoyang; He, Chengfa

2018-05-01

The LiMgPO4: Tb, B ceramic disc is successfully synthesized via improved sintering method which enables the disc sample to have two flat and smooth surfaces. It is worth mentioning that the OSL signal intensity of LiMgPO4: Tb, B disc attenuates much faster than that of commercial Al2O3: C. It costs only 1 s to reduce the intensity to 10%, but the Al2O3:C needs more than 40 s to finish it. Some essential OSL properties related to the dose detection method of this sample also have been systematically investigated. Although the dose-response cure would have better linearity with longer recording time, extended recording time (≥6 s) will not make any contribution to the linearity of the curve. If the bleaching time is more than 35 s, the residue created by previous detection (high dose of 10 Gy) would do almost no influence (with a positive deviation lower than 5.59%) on next lower-dose detection (0.1 Gy). The material would reach its service life when the total-ionizing dose runs up to 30 k Gy. Therefore, the LiMgPO4: Tb, B ceramic material is a potential candidate for real-time dose monitoring with optical fiber telemetering technology.

Intravascular low-intensity He-Ne laser irradiation therapy on idiopathic edema

NASA Astrophysics Data System (ADS)

Gao, Yunqing; Liu, T. C.; Tang, Xiang-Jun

1998-11-01

194 patients with psoriasis were treated by intravascular low level laser irradiation combined with Vit C 2.0g iv and O2 inhale to the nose. An hour once a day, for 5-40 times, and 13.06 times in average, ten times with 4-7 days intervals. The results: cured 23 cases, good effected 61 cases, improved 110 cases, relapsed 10 cases. Curative effect was related to treatment times, cured and good effected 5 times 12.5 percent, 10 times 31 percent, 15 times 94 percent. A matched control group in 17 patients was treated by drug. The results: good effected 1 case, improved 13 cases, not effected 3 cases.

In Site Analysis of a High Temperature Cure Reaction in Real Time Using Modulated Fiber-Optic FT-Raman Spectroscopy

NASA Technical Reports Server (NTRS)

Cooper, John; Aust, Jeffrey F.; Wise, Kent L.; Jensen, Brian J.

1999-01-01

The vibrational spectrum of a high temperature (330 C) polymerization reaction was successfully monitored in real time using a modulated fiber-optic FT-Raman spectrometer. A phenylethynyl terminated monomer was cured, and spectral evidence for two different reaction products was acquired. The products are a conjugated polyene chain and a cyclized trimer. This is the first report describing the use of FT-Raman spectroscopy to monitor a high temperature (greater than 250 C) reaction in real time.

In Situ Analysis of a High-Temperature Cure Reaction in Real Time Using Modulated Fiber-Optic FT-Raman Spectroscopy

NASA Technical Reports Server (NTRS)

Aust, Jeffrey F.; Cooper, John B.; Wise, Kent L.; Jensen, Brian J.

1999-01-01

The vibrational spectrum of a high-temperature (330 C) polymerization reaction was successfully monitored in real time with the use of a modulated fiber-optic Fourier transform (FT)-Raman spectrometer. A phenylethynyl-terminated monomer was cured, and spectral evidence for two different reaction products was acquired. The products are a conjugated polyene chain and a cyclized trimer. This is the first report describing the use of FT-Raman spectroscopy to monitor a high temperature (greater than 250 C) reaction in real time.

Rare occurrence of metastasis from lung cancer to the anus: case report and review of the literature.

PubMed

Al-Tarakji, Mohannad; Feilchenfeldt, Jonas; Haidar, Abdulrazzaq; Szabados, Lajos; Abdelaziem, Sherif; Sayed, Ali; Toro, Adriana; Di Carlo, Isidoro

2016-06-08

Anal metastases from lung cancer are infrequent, and there are only 10 published cases. Life expectancy is no longer than 1 year after diagnosis because of the typically advanced stage of disease. Treatment, which is typically inefficient, is administered with the intent to cure or avoid local complications. We report a case of a patient with non-small cell lung cancer presenting with perianal metastasis mimicking an abscess. Because perianal masses may be misdiagnosed, patients with lung and other cancers should be evaluated for metastatic disease.

Hydrotherapy in state mental hospitals in the mid-twentieth century.

PubMed

Harmon, Rebecca Bouterie

2009-08-01

This research describes nurses' experiences in administering "the water cure," hot or cold wet sheet packs, and continuous tub baths in state mental hospitals during the early twentieth century. Student and graduate nurses were required to demonstrate competence in hydrotherapy treatments used to calm agitated or manic patients in the era before neuroleptics. The nurses interviewed for this study indicated that, although labor intensive, hydrotherapy worked, at least temporarily. Although no longer used in state hospitals, hydrotherapy is regaining popularity with the general public and may serve as an adjunct to pharmacological treatments to calm hospitalized patients in the future.

Comparison of TVT and TVT-O in patients with stress urinary incontinence: short-term cure rates and factors influencing the outcome. A prospective randomised study.

PubMed

Karateke, Ates; Haliloglu, Berna; Cam, Cetin; Sakalli, Mustafa

2009-02-01

Recently, mid-urethral slings have been commonly used in treatment of patients with stress urinary incontinence (SUI). To investigate tension-free vaginal tape (TVT) and tension-free obturator tape (TVT-O) for surgical treatment of SUI for cure rates (primary endpoint), complications and factors influencing cure rate (secondary endpoints). One-hundred and sixty-four patients were included in the study (n = 81 for TVT, n = 83 for TVT-O). The cure rates, complications, preoperative and postoperative urodynamic evaluation, Q-tip test, the Turkish version of Incontinence Impact Questionnaire (IIQ-7) and Urogenital Distress Inventory (UDI-6) scores were recorded. At three and 12 months, the patients were evaluated regarding outcome measures. The cure rates were similar in TVT and TVT-O groups, 88.9% versus 86.7% respectively. Mean operative time was significantly shorter in TVT-O group (P = 0.001). The cure rate was significantly higher in both groups in patients with urethral hypermobility when compared with those with no hypermobility (P = 0.001). The TVT and TVT-O procedures appear to be equally effective for the treatment of SUI. Also, urethral hypermobility seems to be a factor influencing cure rate of mid-urethral slings.

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.

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.

Estimation of the cure rate in Iranian breast cancer patients.

PubMed

Rahimzadeh, Mitra; Baghestani, Ahmad Reza; Gohari, Mahmood Reza; Pourhoseingholi, Mohamad Amin

2014-01-01

Although the Cox's proportional hazard model is the popular approach for survival analysis to investigate significant risk factors of cancer patient survival, it is not appropriate in the case of log-term disease free survival. Recently, cure rate models have been introduced to distinguish between clinical determinants of cure and variables associated with the time to event of interest. The aim of this study was to use a cure rate model to determine the clinical associated factors for cure rates of patients with breast cancer (BC). This prospective cohort study covered 305 patients with BC, admitted at Shahid Faiazbakhsh Hospital, Tehran, during 2006 to 2008 and followed until April 2012. Cases of patient death were confirmed by telephone contact. For data analysis, a non-mixed cure rate model with Poisson distribution and negative binomial distribution were employed. All analyses were carried out using a developed Macro in WinBugs. Deviance information criteria (DIC) were employed to find the best model. The overall 1-year, 3-year and 5-year relative survival rates were 97%, 89% and 74%. Metastasis and stage of BC were the significant factors, but age was significant only in negative binomial model. The DIC also showed that the negative binomial model had a better fit. This study indicated that, metastasis and stage of BC were identified as the clinical criteria for cure rates. There are limited studies on BC survival which employed these cure rate models to identify the clinical factors associated with cure. These models are better than Cox, in the case of long-term survival.

Influence of salt content and processing time on sensory characteristics of cooked "lacón".

PubMed

Purriños, Laura; Bermúdez, Roberto; Temperán, Sara; Franco, Daniel; Carballo, Javier; Lorenzo, José M

2011-04-01

The influence of salt content and processing time on the sensory properties of cooked "lacón" were determined. "Lacón" is a traditional dry-cured and ripened meat product made in the north-west of Spain from the fore leg of the pig, following a similar process to that of dry-cured ham. Six batches of "lacón" were salted with different amounts of salt (LS (3 days of salting), MS (4 days of salting) and HS (5 days of salting)) and ripened during two times (56 and 84 days of dry-ripening). Cured odour in all batches studied, red colour and rancid odour in MS and HS batches, flavour intensity in MS batch and fat yellowness, rancid flavour and hardness in the HS batch were significantly different with respect to the time of processing. Appearance, odour, flavour and texture were not significantly affected by the salt content (P>0.05). However, the saltiness score showed significant differences with respect to the salt levels in all studied batches (56 and 84 days of process). The principal component analysis showed that physicochemical traits were the most important ones concerning the quality of dry-cured "lacón" and offered a good separation of the mean samples according to the dry ripening days and salt level. © 2010 The American Meat Science Association. Published by Elsevier Ltd. All rights reserved.

In vitro bond strength and fatigue stress test evaluation of different adhesive cements used for fixed space maintainer cementation

PubMed Central

Cantekin, Kenan; Delikan, Ebru; Cetin, Secil

2014-01-01

Objective: The purposes of this research were to (1) compare the shear-peel bond strength (SPBS) of a band of a fixed space maintainer (SM) cemented with five different adhesive cements; and (2) compare the survival time of bands of SM with each cement type after simulating mechanical fatigue stress. Materials and Methods: Seventy-five teeth were used to assess retentive strength and another 50 teeth were used to assess the fatigue survival time. SPBS was determined with a universal testing machine. Fatigue testing was conducted in a ball mill device. Results: The mean survival time of bands cemented with R & D series Nova Glass-LC (6.2 h), Transbond Plus (6.7 h), and R & D series Nova Resin (6.8 h) was significantly longer than for bands cemented with Ketac-Cem (5.4 h) and GC Equia (5.2 h) (P < 0.05). Conclusion: Although traditional glass ionomer cement (GIC) cement presented higher retentive strength than resin-based cements (resin, resin modified GIC, and compomer cement), resin based cements, especially dual cure resin cement (nova resin cement) and compomer (Transbond Plus), can be expected to have lower failure rates for band cementation than GIC (Ketac-Cem) in the light of the results of the ball mill test. PMID:25202209

Microleakage of light-cured resin and resin-modified glass-ionomer dentin bonding agents applied with co-cure vs pre-cure technique.

PubMed

Tulunoglu, O; Uçtaşh, M; Alaçam, A; Omürlü, H

2000-01-01

This in vitro study evaluated the effect of dentin bonding agents in reducing microleakage after three months in Class V restorations restored with Z100 resin composite. Materials tested were three types of resin-based dentin bonding agents: a multi-step (Scotchbond Multi-Purpose); a one-step (Scotchbond One-Step); a self-etching, self-priming (Clearfil Liner Bond) and a resin-modified glass ionomer (GC Fuji Bond LC). Class V cavity preparations with occlusal margins in enamel and gingival margins in cementum were prepared both on labial and lingual surfaces of extracted premolar teeth. Restorations (two per tooth) were distributed randomly into nine test groups (n = 10) consisting of the various DBAs applied with co-cure and pre-cure techniques, and no dentin bonding as a negative control group. Samples were stored in saline for three months, thermocycled, stained with silver nitrate, then sectioned through the middle of the preparation to facilitate the removal of the composite resin restoration. For groups treated with the pre-cure technique, the differences between the enamel leakage values of SBMP-control, CFLB-control and SB1S-control subgroups were significant (p < 0.05). For enamel leakage values of groups treated with the co-cure technique, the differences between the SBMP-control, SB1S-control, CFLB-control and Fuji LC-control subgroups were significant (p < 0.05). For cementum leakage values of groups treated with pre-cure technique, the difference between the CFLB-control and the Fuji, SBMP and SB1S groups was significant (p < 0.05). No significant differences could be detected between the cementum leakage values of groups treated with the co-cure technique (p > 0.05). The differences between the values obtained with application of CFLB with the pre-cure and co-cure techniques at the cementum margins were found to be statistically significant (p = 0.02). No statistically significant differences could be detected between the pre-cure and co-cure values of the other test materials. Generally for every group, cementum microleakage values were greater than enamel microleakage values (p < 0.05). The use of Scotchbond Multi-Purpose, Scotchbond One-Step and Fuji Bond LC with the co-cure technique to decrease the application time did not cause any significant increase in microleakage. Only pre-curing using Clearfil Liner Bond provided better microleakage properties than the other pre-cured adhesives.

Magic from Human Regenerative Technologies--Stem Cells

ERIC Educational Resources Information Center

Ritz, John M.

2012-01-01

Many people suffer from chronic diseases and problems due to injury from accidents or ailments. Some problems, such as measles and cancer, can be cured or put into remission with time, medicine, or treatments. Other ailments, such as high blood pressure, failing kidneys, and cystic fibrosis, cannot be cured and require continuous use of…

Discovery – Methotrexate: Chemotherapy Treatment for Cancer

Cancer.gov

Prior to the 1950s, treatment for the majority of cancers was limited to either surgery or the use of radiation. The discovery of the use of methotrexate in curing a rare cancer marked the first time a cancer had been cured. This led to the development of many of today’s common cancer treatments.

Bond Potential of Lithium Disilicate to Heat-Cured Polymethylmethacrylate (PMMA)

DTIC Science & Technology

2015-06-01

system eliminates the need for flasking, boil-out, and long processing times. Instead, the base is light-cured while the teeth are placed with a VLC set...component of previous studies causing failure can be challenged . The stronger ceramic may be durable enough to more accurately measure the bond strength

Revisiting the Posttherapeutic Cure Criterion in Chagas Disease: Time for New Methods, More Questions, Doubts, and Polemics or Time to Change Old Concepts?

PubMed Central

de Lana, Marta; Martins-Filho, Olindo Assis

2015-01-01

One of the most relevant issues beyond the effectiveness of etiological treatment of Chagas disease is the lack of consensual/feasible tools to identify and certify the definitive parasitological cure. Several methods of distinct natures (parasitological, serological, and molecular) have been continuously proposed and novel perspectives are currently under investigation. Although the simultaneous use of distinct tests may offer better contributions and advances, it also leads to controversies of interpretation, with lack of mutual consent of cure criterion amongst researchers and physicians. In fact, when distinct host compartments (blood/tissues) are evaluated and explored, novel questions may arise due to the nature and sensitivity limit of each test. This short analytical review intends to present a chronological and critical overview and discuss the state-of-the-art distinct devices available for posttherapeutic cure assessment in Chagas disease, their contributions, meanings, and interpretation, aiming to point out the major gaps and propose novel insight for future perspectives of posttherapeutic management of Chagas disease patients. PMID:26583124

Cancer survivors' understanding of the cause and cure of their illness: Religious and secular appraisals.

PubMed

Carney, Lauren M; Park, Crystal L

2018-02-28

Little is known about survivors' understanding of the cause of their cancer and of their recovery, nor how these ways of understanding relate to their well-being. No study has examined both secular and religious appraisals of the same event. The current study aimed to examine both religious (God) and secular (self) appraisals of both the cause (attributions) and course/cure of cancer in relation to multiple aspects of adjustment. Data were obtained from a sample of cancer survivors at Time 1 (n = 250) and 1 year later (Time 2, n = 167). Cancer survivors endorsed higher appraisals relating to course/cure of their cancer than those relating to cause, and they endorsed both secular and religious appraisals. Appraisals of the cause and course/cure of cancer were differentially related to adjustment, such that self-attributions of cause and God-attributions of cause were related to negative aspects of adjustment (eg, negative affect and pessimism), while appraisals of self and God's control over the course/cure were related to positive aspects of adjustment (eg, perceived positive life and health changes since cancer). Religiosity did not moderate most of relationships between religious appraisals and adjustment outcomes. Secular and religious appraisals of cancer are not mutually exclusive, and religious appraisals are associated with adjustment regardless of survivors' religiosity. Appraisals relating to cause and course/cure have differential relationships with well-being. Addressing cancer survivors' appraisals-religious or nonreligious-in a therapeutic setting may be beneficial regardless of their reported religiosity. Copyright © 2018 John Wiley & Sons, Ltd.

Properties of ambient cured blended alkali activated cement concrete

NASA Astrophysics Data System (ADS)

Talha Junaid, M.

2017-11-01

This paper presents results of the development and strength properties of ambient-cured alkali activated geopolymer concrete (GPC). The study looks at the strength properties, such as compressive strength, splitting tensile strength, and elastic modulus of such concretes and its dependency on various parameters. The parameters studied in this work are the type and proportions of pre-cursor materials, type of activator and their respective ratios and the curing time. Two types of pre-cursor material; low calcium fly ash (FA) and ground granulated blast furnace slag (GGBFS) were activated using different proportions of sodium silicate and sodium hydroxide solutions. The results indicate that ambient cured geopolymer concrete can be manufactured to match strength properties of ordinary Portland cement concrete (OPC). The strength properties of GPC are dependent on the type and ratio of activator and the proportion of GGBFS used. Increasing the percentage of GGBFS increased the compressive and tensile strengths, while reducing the setting time of the mix. The effect of GGBFS on strength was more pronounced in mixes that contained sodium silicate as activator solution. Unlike OPC, ambient-cured GPC containing sodium silicate gain most of their strength in the first 7 days and there is no change in strength thereafter. However, GPC mixes not containing sodium silicate only achieve a fraction of their strength at 7 days and extended curing is required for such concretes to gain full strength. The results also indicate that the elastic modulus values of GPC mixes without sodium silicate are comparable to OPC while mixes with sodium silicate have elastic modulus values much lower than ordinary concrete.

Survival of selected foodborne pathogens on dry cured pork loins.

PubMed

Morales-Partera, Ángela M; Cardoso-Toset, Fernando; Jurado-Martos, Francisco; Astorga, Rafael J; Huerta, Belén; Luque, Inmaculada; Tarradas, Carmen; Gómez-Laguna, Jaime

2017-10-03

The safety of ready-to-eat products such as cured pork loins must be guaranteed by the food industry. In the present study, the efficacy of the dry curing process of pork loins obtained from free-range pigs in the reduction of three of the most important foodborne pathogens is analysed. A total of 28 pork loin segments, with an average weight of 0.57±0.12kg, were divided into four groups with three being inoculated by immersion with 7logCFU/ml of either Salmonella Typhimurium, Campylobacter coli or Listeria innocua and the last one inoculated by immersion with sterile medium (control group). The loin segments were treated with a seasoning mixture of curing agents and spices, packed in a synthetic sausage casing and cured for 64days. Microbiological analysis, pH and water activity (a w ) were assessed at four stages. The values of pH and a w decreased with curing time as expected. S. Typhimurium and C. coli dropped significantly (3.28 and 2.14 log units, respectively), but limited reduction of L. innocua (0.84 log unit) was observed along the curing process. In our study, three factors were considered critical: the initial concentration of the bacteria, the progressive reduction of pH and the reduction of a w values. Our results encourage performing periodic analysis at different stages of the manufacturing of dry cured pork loins to ensure the absence of the three evaluated foodborne pathogens. Copyright © 2017 Elsevier B.V. All rights reserved.

Influence of curing protocol and ceramic composition on the degree of conversion of resin cement.

PubMed

Lanza, Marcos Daniel Septimio; Andreeta, Marcello Rubens Barsi; Pegoraro, Thiago Amadei; Pegoraro, Luiz Fernando; Carvalho, Ricardo Marins De

2017-01-01

Due to increasing of aesthetic demand, ceramic crowns are widely used in different situations. However, to obtain long-term prognosis of restorations, a good conversion of resin cement is necessary. To evaluate the degree of conversion (DC) of one light-cure and two dual-cure resin cements under a simulated clinical cementation of ceramic crowns. Prepared teeth were randomly split according to the ceramic's material, resin cement and curing protocol. The crowns were cemented as per manufacturer's directions and photoactivated either from occlusal suface only for 60 s; or from the buccal, occlusal and lingual surfaces, with an exposure time of 20 s on each aspect. After cementation, the specimens were stored in deionized water at 37°C for 7 days. Specimens were transversally sectioned from occlusal to cervical surfaces and the DC was determined along the cement line with three measurements taken and averaged from the buccal, lingual and approximal aspects using micro-Raman spectroscopy (Alpha 300R/WITec®). Data were analyzed by 3-way ANOVA and Tukey test at =5%. Statistical analysis showed significant differences among cements, curing protocols and ceramic type (p<0.001). The curing protocol 3x20 resulted in higher DC for all tested conditions; lower DC was observed for Zr ceramic crowns; Duolink resin cement culminated in higher DC regardless ceramic composition and curing protocol. The DC of resin cement layers was dependent on the curing protocol and type of ceramic.

Investigation of a carbon fiber/epoxy prepreg curing behavior for thick composite materials production: An industrial case-study

NASA Astrophysics Data System (ADS)

Giorgini, Loris; Mazzocchetti, Laura; Minak, Giangiacomo; Dolcini, Enrico

2012-07-01

A case-study is presented, in cooperation with RI-BA Composites srl, where the industrial production of a thick part for primary structural application is analysed. The final product is a bulk carbon fiber reinforced object characterized by great dimensions, with thickness ranging between 10mm and 35mm and obtained by Hand-Lay-Up of prepregs. The study shows that prepregs age along the time required for the process work up. Moreover, the isothermal curing investigation of the prepreg used in the production gives some useful hint for the design of a new thermal curing cycle, in order to avoid exotherm problems along the thickness of the object. The effect of the applied curing cycle on thermal properties of the object are reported.

Polymerization shrinkage and hygroscopic expansion of contemporary posterior resin-based filling materials--a comparative study.

PubMed

Rüttermann, Stefan; Krüger, Sören; Raab, Wolfgang H-M; Janda, Ralf

2007-10-01

To investigate the polymerization shrinkage and hygroscopic expansion of contemporary posterior resin-based filling materials. The densities of SureFil (SU), CeramXMono (CM), Clearfil AP-X (CF), Solitaire 2 (SO), TetricEvoCeram (TE), and Filtek P60 (FT) were measured using the Archimedes' principle prior to and 15min after curing for 20, 40 and 60s and after 1h, 24h, 7 d, and 30 d storage at 37 degrees C in water. Volumetric changes (DeltaV) in percent after polymerization and after each storage period in water were calculated from the changes of densities. Water sorption and solubility were determined after 30 d for all specimens and their curing times. Two-way ANOVA was calculated for shrinkage and repeated measures ANOVA was calculated for hygroscopic expansion (p<0.05). DeltaV depended on filler load but not on curing time (SU approximately -2.0%, CM approximately -2.6%, CF approximately -2.1%, SO approximately -3.3%, TE approximately -1.7%, FT approximately -1.8%). Hygroscopic expansion depended on water sorption and solubility. Except for SU, all materials showed DeltaV approximately +1% after water storage. Polymerization shrinkage depended on the type of resin-based filling material but not on curing time. Shrinkage was not compensated by hygroscopic expansion.

Application of addition-cured silicone denture relining materials to adjust mouthguards.

PubMed

Fukasawa, Shintaro; Churei, Hiroshi; Chowdhury, Ruman Uddin; Shirako, Takahiro; Shahrin, Sharika; Shrestha, Abhishekhi; Wada, Takahiro; Uo, Motohiro; Takahashi, Hidekazu; Ueno, Toshiaki

2016-01-01

The purposes of this study were to examine the shock absorption capability of addition-cured silicone denture relining materials and the bonding strength of addition-cured silicone denture relining materials and a commercial mouthguard material to determine its applicability to mouthguard adjustment. Two addition-cured silicone denture relining materials and eleven commercial mouthguard materials were selected as test materials. The impact test was applied by a free-falling steel ball. On the other hand, bonding strength was determined by a delamination test. After prepared surface treatments using acrylic resin on MG sheet surface, 2 types of addition-cured silicone denture relining materials were glued to MG surface. The peak intensity, the time to peak intensity from the onset of the transmitted force and bonding strength were statistically analyzed using ANOVA and Tukey's honest significant difference post hoc test (p<0.05). These results suggest that the silicone denture relining materials could be clinically applicable as a mouthguard adjustment material.

All-fiber optoelectronic sensor with Bragg gratings for in-situ cure monitoring

NASA Astrophysics Data System (ADS)

Cusano, Andrea; Breglio, Giovanni; Cutolo, Antonello; Calabro, Antonio M.; Giordano, Michele; Nicolais, Luigi, II

2000-08-01

Real-time, in situ monitoring for quality control of the polymer cure process is of high interest, since thermoset polymer-matrix composite are widely used in large industrial areas: aeronautical, aerospace, automotive and civil due to their low cost/low weight features. However, their final properties are strongly dependence on the processing parameters, such as temperature and pressure sequence. The key-point for advanced composite materials is the possibility to have distributed and simultaneous monitoring of chemoreological and physical properties during the cure process. To this aim, we have developed and tested an optoelectronic fiber optic sensor based on the Fresnel principle able to monitor the variations of the refractive index due to the cure process of an epoxy based resin. Experimental results have been obtained on sensor capability to monitor the cure kinetics by assuming the refractive index as reaction co-ordinate. The integration with in-fiber Bragg grating in order to measure the local temperature has been discussed and tested.

Antigen-triggered interferon-γ and interleukin-10 pattern in cured mucosal leishmaniasis patients is shaped during the active phase of disease.

PubMed

Nogueira, R S; Gomes-Silva, A; Bittar, R C; Silva Mendonça, D; Amato, V S; da Silva Mattos, M; Oliveira-Neto, M P; Coutinho, S G; Da-Cruz, A M

2014-09-01

An exacerbated type 1 response to leishmanial antigens is the basis of tissue destruction observed in mucosal leishmaniasis (ML). After therapy, a persistent production of high levels of inflammatory cytokines can confer a poor prognosis. Herein we investigated whether the clinical conditions defined during the active phase of ML affect the magnitude of long-term anti-Leishmania immune response. Twenty clinically cured ML cases were studied. Peripheral blood mononuclear cells (PBMC) were cultured with L. braziliensis antigens (Lb-Ag), Toxoplasma gondii antigens (Tg-Ag), concanavalin-A (Con-A) or medium alone, and the lymphocyte proliferative response and cytokine secretion were quantified. Medical records were reviewed for Montenegro skin test (MST) during diagnosis, duration of ML disease or time elapsed after clinical cure. The duration of disease was correlated positively with MST (r = 0·61). Lb-Ag induced interferon (IFN)-γ was correlated positively with duration of illness (r = 0·69) as well as the frequency of secreting cells [enzyme-linked immunospot (ELISPOT)] assay. No association was observed for Tg-Ag or Con-A. Disease duration was correlated negatively with interleukin (IL)-10 production (r = -0·76). Moreover, a negative correlation between length of time after clinical cure and TNF levels (r = -0·94) or the IFN-γ : IL-10 ratio (r = -0·89) were also seen. We suggest that the magnitude of the IFN-γ inflammatory response triggered by ML can be driven by the time of leishmanial antigens exposition during the active phase of the disease. This pattern could persist even long-term after cure. However, despite IFN-γ levels, the decrease of the TNF and IFN-γ : IL-10 ratio reflects the control of proinflammatory responses achieved by cure of ML, possibly preventing disease relapses. © 2014 The Authors. Clinical & Experimental Immunology published by John Wiley & Sons Ltd on behalf of British Society for Immunology.

Novel Concrete Chemistry Achieved with Low Dose Gamma Radiation Curing and Resistance to Neutron Activation

NASA Astrophysics Data System (ADS)

Burnham, Steven Robert

As much as 50% of ageing-related problems with concrete structures can be attributed to con-struction deficiencies at the time of placement. The most influential time affecting longevity of concrete structures is the curing phase, or commonly the initial 28 days following its placement. A novel advanced atomistic analysis of novel concrete chemistry is presented in this dissertation with the objective to improve concrete structural properties and its longevity. Based on experiments and computational models, this novel concrete chemistry is discussed in two cases: (a) concrete chemistry changes when exposed to low-dose gamma radiation in its early curing stage, thus improving its strength in a shorter period of time then curing for the conventional 28 days; (b) concrete chemistry is controlled by its atomistic components to assure strength is not reduced but that its activation due to long-term exposure to neutron flux in nuclear power plants is negligible. High dose gamma radiation is well documented as a degradation mechanism that decreases concrete's compressive strength; however, the effects of low-dose gamma radiation on the initial curing phase of concrete, having never been studied before, proved its compressive strength increases. Using a 137 Cs source, concrete samples were subjected to gamma radiation during the initial curing phase for seven, 14, and 28 days. The compressive strength after seven days is improved for gamma cured concrete by 24% and after 14 days by 76%. Concrete shows no improvement in compressive strength after 28 days of exposure to gamma radiation, showing that there is a threshold effect. Scanning Electron Microscopy is used to examine the microstructure of low-dose gamma radiation where no damage to its microstructure is found, showing no difference between gamma cured and conventionally cured concrete. Molecular dynamics modeling based on the MOPAC package is used to study how gamma radiation during the curing stage improves compressive strength of concrete. The modeling shows that when radiolysis occurs in freshly mixed concrete, the reactivity between key molecules responsible for bonding between cement and aggregate is enhanced due to improved reactivity at the molecular level. A new method is developed that successfully controls a concrete chemistry at the atomistic level by assuring its long-term exposure to neutron flux in nuclear power plants will not activate the dome wall to the level of low-level radioactive waste. This methodology is established to detect and select the level of trace elemental composition in concrete based on a low-flux neutron activation analysis (NAA). By carefully selecting aggregates that do not contain certain elements that activate to high concentrations after decades of concrete exposure to neutron flux, the end of life for concrete is improved by declassifying it as low-level radioactive waste. Directly, it improves economy of commissioning nuclear power plants to be built in near future and reducing important quantities of waste to be disposed at high costs.

Fast Curing of Composite Wood Products

DOE Office of Scientific and Technical Information (OSTI.GOV)

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 compositesmore » 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 alternative approach to accelerated PF curing can be accomplished with the addition amines or amides. The later functionality undergoes base catalyzed hydrolysis yielding the corresponding carboxyl ate and free amine which rapidly reacts with the phenolic methylol groups facilitating polymerization and curing of the PF resin (Pizzi, 1997).« less

Surface microhardness of a resin composite exposed to a "first-generation" LED curing lamp, in vitro.

PubMed

Keogh, Pauraic; Ray, Noel J; Lynch, Christopher D; Burke, Francis M; Hannigan, Ailish

2004-12-01

This investigation determined the minimum exposure times consistent with optimised surface microhardness parameters for a commercial resin composite cured using a "first-generation" light-emitting diode activation lamp. Disk specimens were exposed and surface microhardness numbers measured at the top and bottom surfaces for elapsed times of 1 hour and 24 hours. Bottom/top microhardness number ratios were also calculated. Most microhardness data increased significantly over the elapsed time interval but microhardness ratios (bottom/top) were dependent on exposure time only. A minimum exposure of 40 secs is appropriate to optimise microhardness parameters for the combination of resin composite and lamp investigated.

Evaluation of Vickers hardness and depth of cure of six composite resins photo-activated with different polymerization modes.

PubMed

Poggio, C; Lombardini, M; Gaviati, S; Chiesa, M

2012-07-01

The current in vitro study evaluated Vickers hardness (VK) and depth of cure (hardness ratio) of six resin composites, polymerized with a light-emitting diode (LED) curing unit by different polymerization modes: Standard 20 s, Standard 40 s, Soft-start 40 s. SIX RESIN COMPOSITES WERE SELECTED FOR THE PRESENT STUDY: three microhybrid (Esthet.X HD, Amaris, Filtek Silorane), two nanohybrid (Grandio, Ceram.X mono) and one nanofilled (Filtek Supreme XT). The VK of the surface was determined with a microhardness tester using a Vickers diamond indenter and a 200 g load applied for 15 seconds. The mean VK and hardness ratio of the specimens were calculated using the formula: hardness ratio = VK of bottom surface / VK of top surface. For all the materials tested and with all the polymerization modes, hardness ratio was higher than the minimum value indicated in literature in order to consider the bottom surface as adequately cured (0.80). Curing time did not affect hardness ratio values for Filtek Silorane, Grandio and Filtek Supreme XT. The effectiveness of cure at the top and bottom surface was not affected by Soft-start polymerization mode.

Toward 3D Printing of Medical Implants: Reduced Lateral Droplet Spreading of Silicone Rubber under Intense IR Curing.

PubMed

Stieghorst, Jan; Majaura, Daniel; Wevering, Hendrik; Doll, Theodor

2016-03-01

The direct fabrication of silicone-rubber-based individually shaped active neural implants requires high-speed-curing systems in order to prevent extensive spreading of the viscous silicone rubber materials during vulcanization. Therefore, an infrared-laser-based test setup was developed to cure the silicone rubber materials rapidly and to evaluate the resulting spreading in relation to its initial viscosity, the absorbed infrared radiation, and the surface tensions of the fabrication bed's material. Different low-adhesion materials (polyimide, Parylene-C, polytetrafluoroethylene, and fluorinated ethylenepropylene) were used as bed materials to reduce the spreading of the silicone rubber materials by means of their well-known weak surface tensions. Further, O2-plasma treatment was performed on the bed materials to reduce the surface tensions. To calculate the absorbed radiation, the emittance of the laser was measured, and the absorptances of the materials were investigated with Fourier transform infrared spectroscopy in attenuated total reflection mode. A minimum silicone rubber spreading of 3.24% was achieved after 2 s curing time, indicating the potential usability of the presented high-speed-curing process for the direct fabrication of thermal-curing silicone rubbers.

Design of intelligent composites with life-cycle health management capabilities

NASA Astrophysics Data System (ADS)

Rosania, Colleen L.; Larrosa, Cecilia C.; Chang, Fu-Kuo

2015-03-01

Use of carbon fiber reinforced polymers (CFRPs) presents challenges because of their complex manufacturing processes and different damage mechanics in relation to legacy metal materials. New monitoring methods for manufacturing, quality verification, damage estimation, and prognosis are needed to use CFRPs safely and efficiently. This work evaluates the development of intelligent composite materials using integrated piezoelectric sensors to monitor the material during cure and throughout service life. These sensors are used to propagate ultrasonic waves through the structure for health monitoring. During manufacturing, data is collected at different stages during the cure cycle, detecting the changing material properties during cure and verifying quality and degree of cure. The same sensors can then be used with previously developed techniques to perform damage detection, such as impact detection and matrix crack density estimation. Real-time damage estimation can be combined with prognostic models to predict future propagation of damage in the material. In this work experimental results will be presented from composite coupons with embedded piezoelectric sensors. Cure monitoring and damage detection results derived from analysis of the ultrasonic sensor signal will be shown. Sensitive signal parameters to the different stimuli in both the time and frequency domains will be explored for this analysis. From these results, use of the same sensor networks from manufacturing throughout the life of the composite material will demonstrate the full life-cycle monitoring capability of these intelligent materials.

A sixth-century Irish headache cure and its use in a south German monastery.

PubMed

Isler, H; Hasenfratz, H; O'Neill, T

1996-12-01

Medieval headache treatment is largely unknown. Medieval incantations against headache enumerate bodily organs to be protected. One 8th-century Latin hymn from Lake Constance using this device is addressed to St. Aid "mechprech", who has been identified as Aed Mac Bricc, Bishop of Killare, 6th century. This Irish Saint inspired unusual legends by some rather unorthodox activities: He abducted a young girl as hostage while his inheritance was withheld, but at the same time was seen surrounded by angels. He prayed for a nun who was pregnant and made the pregnancy vanish by a miracle, and he replaced the severed heads of maids, men and horses, creating a new spring as a by-product of this operation. Already at his birth his head had hit a stone, leaving a hole in the stone which collected rainwater that cured all ailments. In our own time, such "bullaun stones" are still believed to cure headache in Ireland. According to the legends collected by Plummer and Colgan, St. Aed Mac Bricc was well known for his power to cure headaches. He relieved St. Brigid's headache when she was suffering many miles away, but his most impressive cure was in convincing a headache sufferer that the patient's headache could actually be transferred own head. The headache hymn or incantation is intended to repeat Aed's unique miracle.

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 was lower when cured with the Apollo 95E for two or three seconds than when cured for six and 12 (2 x 6) seconds, or for 60 seconds with Optilux 500 (p<0.05). For Z100, the amount of linear polymerization shrinkage was lower when cured with the Apollo 95E for two, three and six seconds than for 12 (2 x 6) seconds with Apollo 95E or for 60 seconds with the Optilux 500 (p<0.05). The results of the microhardness test indicated that there was no statistically significant difference in microhardness between groups for the upper surface. However, for the lower surface, when the composites were light cured with Apollo 95E for three seconds as recommended by the manufacturer, microhardness of the lower surface was usually lower than that of the upper surface and did not cure sufficiently. Conclusively, when compared with conventional QTH unit, the PAC unit, Apollo 95E did not properly cure the lower composite surface when the layer thickness exceeded 2 mm. In addition, three seconds of curing time, which the manufacturer recommended, was insufficient for optimal curing of composites.

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.

A semi-empirical approach for the chemoviscosity modeling of reactive resin system

NASA Technical Reports Server (NTRS)

Hou, T. H.; Bai, J. M.

1988-01-01

A new analytical model for simulating chemoviscosity of a thermosetting resin is presented. The model is developed on the basis of the Williams-Landel-Ferry (WLF, 1955) polymer rheology theory for the thermoplastic materials, which was modified to account for the factor of reaction time by introducing a relationship between the glass transition temperature and the degree of cure of the resin system. Theoretical predictions of the chemoviscosity profiles under dynamic curing conditions are shown to compare favorably with the experimental data obtained on the Hercules 3501-6 resin system cured under seven isothermal conditions.

Correlation between elastic and plastic deformations of partially cured epoxy networks

NASA Astrophysics Data System (ADS)

Müller, Michael; Böhm, Robert; Geller, Sirko; Kupfer, Robert; Jäger, Hubert; Gude, Maik

2018-05-01

The thermo-mechanical behavior of polymer matrix materials is strongly dependent on the curing reaction as well as temperature and time. To date, investigations of epoxy resins and their composites mainly focused on the elastic domain because plastic deformation of cross-linked polymer networks was considered as irrelevant or not feasible. This paper presents a novel approach which combines both elastic and plastic domain. Based on an analytical framework describing the storage modulus, analogous parameter combinations are defined in order to reduce complexity when variations in temperature, strain rate and degree of cure are encountered.

Application of a Non-Mixture Cure Rate Model for Analyzing Survival of Patients with Breast Cancer.

PubMed

Baghestani, Ahmad Reza; Moghaddam, Sahar Saeedi; Majd, Hamid Alavi; Akbari, Mohammad Esmaeil; Nafissi, Nahid; Gohari, Kimiya

2015-01-01

As a result of significant progress made in treatment of many types of cancers during the last few decades, there have been an increased number of patients who do not experience mortality. We refer to these observations as cure or immune and models for survival data which include cure fraction are known as cure rate models or long-term survival models. In this study we used the data collected from 438 female patients with breast cancer registered in the Cancer Research Center in Shahid Beheshti University of Medical Sciences, Tehran, Iran. The patients had been diagnosed from 1992 to 2012 and were followed up until October 2014. We had to exclude some because of incomplete information. Phone calls were made to confirm whether the patients were still alive or not. Deaths due to breast cancer were regarded as failure. To identify clinical, pathological, and biological characteristics of patients that might have had an effect on survival of the patients we used a non-mixture cure rate model; in addition, a Weibull distribution was proposed for the survival time. Analyses were performed using STATA version 14. The significance level was set at P ≤ 0.05. A total of 75 patients (17.1%) died due to breast cancer during the study, up to the last follow-up. Numbers of metastatic lymph nodes and histologic grade were significant factors. The cure fraction was estimated to be 58%. When a cure fraction is not available, the analysis will be changed to standard approaches of survival analysis; however when the data indicate that the cure fraction is available, we suggest analysis of survival data via cure models.

Chapter 13:Wood/Nonwood Thermoplastic Composites

Treesearch

Craig M. Clemons; Roger M. Rowell; David Plackett; B. Kristoffer Segerholm

2013-01-01

Composites made from wood, other biomass resources and polymers have existed for a long time but the nature of many of these composites has changed in recent decades. Wood-thermoset composites date to the early 1900s. "Thermosets" or thermosetting polymers are plastics that, once cured, cannot be remelted by heating. These include cured resins such as epoxies...

40 CFR 63.4565 - How do I determine the emission capture system efficiency?

Code of Federal Regulations, 2010 CFR

2010-07-01

... solvent flash-off, curing, and drying occurs within the capture system; and the removal or evaporation of..., this criterion is not met if parts enter the open shop environment when being moved between a spray... surface preparation activities and drying and curing time. (c) Liquid-to-uncaptured-gas protocol using a...

40 CFR 63.4765 - How do I determine the emission capture system efficiency?

Code of Federal Regulations, 2010 CFR

2010-07-01

... coating, curing, and drying occurs within the capture system; and the removal or evaporation of cleaning... criterion is not met if parts enter the open shop environment when being moved between a spray booth and a... activities and drying or curing time. (c) Liquid-to-uncaptured-gas protocol using a temporary total enclosure...

The Effect of Curing Temperature on the Fracture Toughness of Fiberglass Epoxy Composites

NASA Astrophysics Data System (ADS)

Ryan, Thomas J.

The curing reaction in a thermoset polymer matrix composite is often accelerated by the addition of heat in an oven or autoclave. The heat added increases the rate of the polymerization reaction and cross-linking in the material. The cure cycle used (temperature, pressure and time) can therefore alter the final material properties. This research focuses on how the curing temperature (250, 275, 300 °F) affects the yield strength and the mode I interlaminar fracture toughness, GI, of a unidirectional S-2 glass epoxy composite. The test method that was used for the tension test was ASTM D3039 and the test method for the mode I interlaminar fracture toughness, the double cantilever beam (DCB) test, was ASTM D5528. The DCB specimens were fabricated with a non-adhesive insert at the midplane of the composite that serves as the initiatior of the delamination. Opening forces were then applied to the specimen, causing the crack propagation. The results show that increasing the cure temperature by 50 °F increased the tensile strength by 10% (86.54 - 94.73 ksi) and decreased the fracture toughness 20% (506.23 - 381.31 J/m 2). Thus, the curing temperature can cause a trade-off between these two properties, which means that the curing cycle will need to be altered based on the intended use and the required material properties.

Development of a modified dry curing process for beef.

PubMed

Hayes, J E; Kenny, T A; Ward, P; Kerry, J P

2007-11-01

The development of a dry curing process using physical treatments to promote the diffusion of the cure ingredients was studied. Vacuum pulsing with and without tumbling, continuous vacuum, and tumbling only treatments were compared with a conventional static dry cure control method on beef M. supraspinatus. Vacuum tumble and tumble only treatments gave highest core salt content after 7 days conditioning (3.3% and 3.1%, respectively). All test treatments resulted in higher colour uniformity and lower % cook loss in comparison to control (P<0.001). The control and vacuum pulsed samples were tougher (P<0.001). Vacuum tumble and tumble only treatments gave higher acceptability (P<0.001). Based on these findings for M. supraspinatus, indicating that the vacuum tumble treatments gave the best results, further testing of this method was conducted using the M. biceps femoris in addition to the M. supraspinatus. Cured beef slices were stored in modified atmosphere packs (MAP) (80%N(2):20%CO(2)) for up to 28 day at 4°C. Redness (a(∗), P<0.001) decreased over storage time in M. biceps femoris. Vacuum tumble treatment increased (P<0.05) redness in M. supraspinatus. Results obtained demonstrate the benefits of vacuum tumbling over the other physical treatments as a method for accelerating the dry curing process, producing dry cured beef products with enhanced organoleptic quality and increased yields.

A Phase 3, Multicenter, Randomized, Double-Blind, Vehicle-Controlled Study Evaluating the Safety and Efficacy of Metronidazole Vaginal Gel 1.3% in the Treatment of Bacterial Vaginosis

PubMed Central

Schwebke, Jane R.; Marrazzo, Jeanne; Beelen, Andrew P.; Sobel, Jack D.

2015-01-01

Background Bacterial vaginosis (BV), a prevalent infection in women of reproductive age, is associated with increased risk of upper genital tract and sexually transmitted infections, and complications in pregnancy. Currently approved treatments include metronidazole, which requires once or twice daily intravaginal administration for 5 days or twice daily oral administration for 7 days. This phase 3 study determined the safety and efficacy of single-dose metronidazole vaginal gel (MVG) 1.3%. Methods In this double-blind, vehicle-controlled study, 651 women with clinical diagnosis of BV were randomized 1:1 to receive MVG 1.3% or vehicle vaginal gel. Primary efficacy measure was clinical cure (normal discharge, negative “whiff test,” and <20% clue cells) at day 21. Secondary measures included therapeutic cure (both clinical and bacteriological; day 21) and bacteriologic cure (Nugent score <4), clinical cure, and time to resolution of symptoms (day 7). Results A total of 487 participants were included in the primary analysis. Clinical and therapeutic cure rates (day 21) were higher in participants treated with MVG 1.3% compared with vehicle gel (37.2% vs. 26.6% [P = 0.010] and 16.8% vs. 7.2% [P = 0.001], respectively). Clinical and bacteriologic cure rates (day 7) were also higher in the MVG 1.3% group (46.0% vs. 20.0% [P < 0.001] and 32.7% vs. 6.3% [P < 0.001], respectively). The median time to resolution of symptoms was shorter in the MVG 1.3% (day 6) than vehicle group (not reached). No serious adverse events were reported, and incidence was similar across treatment groups. Conclusions Single-dose MVG 1.3% was safe and superior to vehicle gel in producing cure among women with BV. PMID:26222750

Adhesive curing through low-voltage activation

PubMed Central

Ping, Jianfeng; Gao, Feng; Chen, Jian Lin; Webster, Richard D.; Steele, Terry W. J.

2015-01-01

Instant curing adhesives typically fall within three categories, being activated by either light (photocuring), heat (thermocuring) or chemical means. These curing strategies limit applications to specific substrates and can only be activated under certain conditions. Here we present the development of an instant curing adhesive through low-voltage activation. The electrocuring adhesive is synthesized by grafting carbene precursors on polyamidoamine dendrimers and dissolving in aqueous solvents to form viscous gels. The electrocuring adhesives are activated at −2 V versus Ag/AgCl, allowing tunable crosslinking within the dendrimer matrix and on both electrode surfaces. As the applied voltage discontinued, crosslinking immediately terminated. Thus, crosslinking initiation and propagation are observed to be voltage and time dependent, enabling tuning of both material properties and adhesive strength. The electrocuring adhesive has immediate implications in manufacturing and development of implantable bioadhesives. PMID:26282730

Effect of Dental Chair Light on Enamel Bonding of Orthodontic Brackets Using Light Cure Based Adhesive System: An In-Vitro Study

PubMed Central

Tiwari, Anil; Shyagali, Tarulatha; Kohli, Sarvraj; Joshi, Rishi; Gupta, Abhishek; Tiwari, Rana

2016-01-01

Aim: The aim of this in vitro study was to evaluate the influence of the Dental chair light on the bond strength of light cured composite resin. Materials and Methods: Sixty therapeutically extracted human premolar teeth were randomly allocated to two groups of 30 specimens each. In both groups light cured composite resin (Transbond XT) and MBT premolar metal brackets (3M Unitek) was used to bond brackets. In group I and II light curing was done using Light-emitting diode light curing units without and with the dental chair light respectively. After bonding, all samples were stored in distilled water at room temperature for 24 hours and subsequently tested for shear bond strength and Adhesive Remnant Index (ARI) scores. Data was subjected to Mann Whitney U statistical test. Results: Results indicated that there was significantly higher shear bond strength (7.71 ± 1.90) for the Group II (composite cured with LED and dental chair light) compared with Group I (composite cured with LED LCU only) (5.74 ± 1.13).the obtained difference was statistically significant. There was no statistical significant difference between ARI scores in between the groups. Conclusions: light cure bonding with dental chair light switched on will produce greater bond strength than the conventional bonding. However, the ARI score were similar to both the groups. It is advised that the inexperienced orthodontist should always switch off the dental chair light while bonding for enough working time during the bracket placement. PMID:28077886

The application of magnetic resonance microimaging to the visible light curing of dental resins. 3. Stray-field nuclear magnetic resonance imaging (STRAFI).

PubMed

Lloyd, C H; Scrimgeour, S N; Lane, D M; Hunter, G; McDonald, P J

2001-09-01

To investigate the application of stray-field nuclear magnetic resonance imaging (STRAFI) to the visible light curing of dental restorative materials. STRAFI can overcome peak broadening associated with the conventional magnetic resonance microimaging (MRM) of glassy polymers, and has the potential to image dental restorative resins at both low and high degrees of conversion. Cylindrical composite specimens were light-cured from one end to produce some that were fully cured throughout their length and others that were fully cured at one end and uncured at the other. A one-dimensional probe was used to measure the magnetisation in 40 microm thick slices at 100 microm intervals along the length of the specimen. A quadrature pulse sequence was applied and the magnetisation decay recorded in a train of eight echoes. A value for T(2) could be obtained only for the polymer (59+/-16 microms), therefore the echoes were summed to give an approximate indication of the degree of conversion. The echo sum for the monomer was significantly higher than that for the polymer. Differences in composite shade and cure time produced changes in the cure profiles. STRAFI produced measurements for both monomer and polymer in all stages of conversion that allowed cure profiles to be produced. Summing the decay echoes produced a qualitative measure of the condition of the material in the selected slice. The same data can be used to calculate T(2), a quantitative parameter. This first investigation has demonstrated that STRAFI is well suited to polymerisation studies.

Evaluation of the efficacy of intramuscular versus intramammary treatment of subclinical Streptococcus agalactiae mastitis in dairy cows in Colombia.

PubMed

Reyes, J; Chaffer, M; Sanchez, J; Torres, G; Macias, D; Jaramillo, M; Duque, P C; Ceballos, A; Keefe, G P

2015-08-01

A randomized controlled trial was performed in 17 Colombian dairy herds to determine the cure risk among cows subclinically infected with Streptococcus agalactiae exposed to 2 antibiotic therapies. Composite milk samples were collected before milking at the onset of the trial (pretreatment) and 2 subsequent times over a period of approximately 63 d. The intramammary application (IMM) of ampicillin-cloxacillin was compared with the intramuscular application (IM) of penethamate hydriodide, and cure risks after an initial and retreatment application were assessed. Cure risk after the initial treatment was higher (82.4%) for the IMM treatment than for IM therapy (65.8%). However, no difference was observed in the cure risk of refractory cases after retreatment (IMM=52.6% vs. IM=51.2%). The cumulative cure risk (both initial and retreatment) was 90.4 and 82.9% for the IMM and IM products, respectively. A 2-level random effects logistic model that controlled for pretreatment cow-level somatic cell count, indicated that IM treatment (odds ratio=0.37) had a lower cure risk than IMM and a tendency for a lower cure risk with increasing baseline somatic cell count. Our findings suggest that both products and administration routes can reduce the prevalence of S. agalactiae in affected herds, but the IMM product had a better efficacy in curing the infection. In addition to the treatment protocol, the cow somatic cell count should be considered when making management decisions for cows infected with S. agalactiae. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Influence of curing protocol and ceramic composition on the degree of conversion of resin cement

PubMed Central

Lanza, Marcos Daniel Septimio; Andreeta, Marcello Rubens Barsi; Pegoraro, Thiago Amadei; Pegoraro, Luiz Fernando; Carvalho, Ricardo Marins De

2017-01-01

Abstract Due to increasing of aesthetic demand, ceramic crowns are widely used in different situations. However, to obtain long-term prognosis of restorations, a good conversion of resin cement is necessary. Objective: To evaluate the degree of conversion (DC) of one light-cure and two dual-cure resin cements under a simulated clinical cementation of ceramic crowns. Material and Methods: Prepared teeth were randomly split according to the ceramic's material, resin cement and curing protocol. The crowns were cemented as per manufacturer's directions and photoactivated either from occlusal suface only for 60 s; or from the buccal, occlusal and lingual surfaces, with an exposure time of 20 s on each aspect. After cementation, the specimens were stored in deionized water at 37°C for 7 days. Specimens were transversally sectioned from occlusal to cervical surfaces and the DC was determined along the cement line with three measurements taken and averaged from the buccal, lingual and approximal aspects using micro-Raman spectroscopy (Alpha 300R/WITec®). Data were analyzed by 3-way ANOVA and Tukey test at =5%. Results: Statistical analysis showed significant differences among cements, curing protocols and ceramic type (p<0.001). The curing protocol 3x20 resulted in higher DC for all tested conditions; lower DC was observed for Zr ceramic crowns; Duolink resin cement culminated in higher DC regardless ceramic composition and curing protocol. Conclusion: The DC of resin cement layers was dependent on the curing protocol and type of ceramic. PMID:29211292

Exploring factors related to metastasis free survival in breast cancer patients using Bayesian cure models.

PubMed

Jafari-Koshki, Tohid; Mansourian, Marjan; Mokarian, Fariborz

2014-01-01

Breast cancer is a fatal disease and the most frequently diagnosed cancer in women with an increasing pattern worldwide. The burden is mostly attributed to metastatic cancers that occur in one-third of patients and the treatments are palliative. It is of great interest to determine factors affecting time from cancer diagnosis to secondary metastasis. Cure rate models assume a Poisson distribution for the number of unobservable metastatic-component cells that are completely deleted from the non-metastasis patient body but some may remain and result in metastasis. Time to metastasis is defined as a function of the number of these cells and the time for each cell to develop a detectable sign of metastasis. Covariates are introduced to the model via the rate of metastatic-component cells. We used non-mixture cure rate models with Weibull and log-logistic distributions in a Bayesian setting to assess the relationship between metastasis free survival and covariates. The median of metastasis free survival was 76.9 months. Various models showed that from covariates in the study, lymph node involvement ratio and being progesterone receptor positive were significant, with an adverse and a beneficial effect on metastasis free survival, respectively. The estimated fraction of patients cured from metastasis was almost 48%. The Weibull model had a slightly better performance than log-logistic. Cure rate models are popular in survival studies and outperform other models under certain conditions. We explored the prognostic factors of metastatic breast cancer from a different viewpoint. In this study, metastasis sites were analyzed all together. Conducting similar studies in a larger sample of cancer patients as well as evaluating the prognostic value of covariates in metastasis to each site separately are recommended.

Comparison of Borate Bioactive Glass and Calcium Sulfate as Implants for the Local Delivery of Teicoplanin in the Treatment of Methicillin-Resistant Staphylococcus aureus-Induced Osteomyelitis in a Rabbit Model

PubMed Central

Jia, Wei-Tao; Fu, Qiang; Huang, Wen-Hai

2015-01-01

There is growing interest in biomaterials that can cure bone infection and also regenerate bone. In this study, two groups of implants composed of 10% (wt/wt) teicoplanin (TEC)-loaded borate bioactive glass (designated TBG) or calcium sulfate (TCS) were created and evaluated for their ability to release TEC in vitro and to cure methicillin-resistant Staphylococcus aureus (MRSA)-induced osteomyelitis in a rabbit model. When immersed in phosphate-buffered saline (PBS), both groups of implants provided a sustained release of TEC at a therapeutic level for up to 3 to 4 weeks while they were gradually degraded and converted to hydroxyapatite. The TBG implants showed a longer duration of TEC release and better retention of strength as a function of immersion time in PBS. Infected rabbit tibiae were treated by debridement, followed by implantation of TBG or TCS pellets or intravenous injection with TEC, or were left untreated. Evaluation at 6 weeks postimplantation showed that the animals implanted with TBG or TCS pellets had significantly lower radiological and histological scores, lower rates of MRSA-positive cultures, and lower bacterial loads than those preoperatively and those of animals treated intravenously. The level of bone regeneration was also higher in the defects treated with the TBG pellets. The results showed that local TEC delivery was more effective than intravenous administration for the treatment of MRSA-induced osteomyelitis. Borate glass has the advantages of better mechanical strength, more desirable kinetics of release of TEC, and a higher osteogenic capacity and thus could be an effective alternative to calcium sulfate for local delivery of TEC. PMID:26416858

Comparison of Borate Bioactive Glass and Calcium Sulfate as Implants for the Local Delivery of Teicoplanin in the Treatment of Methicillin-Resistant Staphylococcus aureus-Induced Osteomyelitis in a Rabbit Model.

PubMed

Jia, Wei-Tao; Fu, Qiang; Huang, Wen-Hai; Zhang, Chang-Qing; Rahaman, Mohamed N

2015-12-01

There is growing interest in biomaterials that can cure bone infection and also regenerate bone. In this study, two groups of implants composed of 10% (wt/wt) teicoplanin (TEC)-loaded borate bioactive glass (designated TBG) or calcium sulfate (TCS) were created and evaluated for their ability to release TEC in vitro and to cure methicillin-resistant Staphylococcus aureus (MRSA)-induced osteomyelitis in a rabbit model. When immersed in phosphate-buffered saline (PBS), both groups of implants provided a sustained release of TEC at a therapeutic level for up to 3 to 4 weeks while they were gradually degraded and converted to hydroxyapatite. The TBG implants showed a longer duration of TEC release and better retention of strength as a function of immersion time in PBS. Infected rabbit tibiae were treated by debridement, followed by implantation of TBG or TCS pellets or intravenous injection with TEC, or were left untreated. Evaluation at 6 weeks postimplantation showed that the animals implanted with TBG or TCS pellets had significantly lower radiological and histological scores, lower rates of MRSA-positive cultures, and lower bacterial loads than those preoperatively and those of animals treated intravenously. The level of bone regeneration was also higher in the defects treated with the TBG pellets. The results showed that local TEC delivery was more effective than intravenous administration for the treatment of MRSA-induced osteomyelitis. Borate glass has the advantages of better mechanical strength, more desirable kinetics of release of TEC, and a higher osteogenic capacity and thus could be an effective alternative to calcium sulfate for local delivery of TEC. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Value of surgery in patients with negative imaging and sporadic Zollinger-Ellison syndrome.

PubMed

Norton, Jeffrey A; Fraker, Douglas L; Alexander, H Richard; Jensen, Robert T

2012-09-01

To address the value of surgery in patients with sporadic Zollinger-Ellison syndrome (ZES) with negative imaging studies. Medical control of acid hypersecretion in patients with sporadic ZES is highly effective. This has led to these patients frequently not being sent to surgery, especially if preoperative imaging studies are negative, due, in large part, to existence of almost no data on the success of surgery in this group. Fifty-eight prospectively studied patients with sporadic ZES (17% of total studied) had negative imaging studies, and their surgical outcome was compared with 117 patients with positive imaging results. Thirty-five patients had negative imaging studies in the pre-somatostatin receptor scintigraphy (SRS) era, and 23 patients in the post-SRS era. Patients with negative imaging studies had long disease histories before surgery [mean ± SEM (from onset) = 7.9 ± 1 [range, -0.25 to 35 years]) and 25% were followed for 2 or more years from diagnosis. At surgery, gastrinoma was found in 57 of 58 patients (98%). Tumors were small (mean = 0.8 cm, 60% <1 cm). The most common primary sites were duodenal 64%, pancreatic 17%, and lymph node (10%). Fifty percent had a primary-only, 41% primary + lymph node, and 7% had liver metastases. Thirty-five of 58 patients (60%) were cured immediately postoperatively, and at last follow-up [mean = -9.4 years; range, 0.2-22 years], 27 patients (46%) remained cured. During follow-up, 3 patients died, each had liver metastases at surgery. In comparison to positive imaging patients, those with negative imaging studies had lower preoperative fasting gastrin levels; had a longer delay before surgery; more frequently had a small duodenal tumor; less frequently had a pancreatic tumor, multiple tumors, or developed a new lesion postoperatively; and had a longer survival. Sporadic ZES patients with negative imaging studies are not rare even in the post-SRS period. An experienced surgeon can find gastrinoma in almost every patient (98%) and nearly one half (46%) are cured, a rate similar to patients with positive imaging findings. Because liver metastases were found in 7%, which may have been caused by a long delay in surgery and all the disease-related deaths occurred in this group, surgery should be routinely undertaken early in ZES patients despite negative imaging studies.

Value of Surgery In Patients With Negative Imaging And Sporadic Zollinger-Ellison Syndrome (ZES)

PubMed Central

Norton, Jeffrey A.; Fraker, Douglas L.; Alexander, H. Richard; Jensen, Robert T

2012-01-01

Objectives To address the value of surgery in sporadic Zollinger-Ellison syndrome (ZES) patients with negative imaging studies. Background Medical control of acid hypersecretion in patients with sporadic Zollinger-Ellison syndrome (ZES) is highly effective. This has led to these patients frequently not sent to surgery, especially if preoperative imaging studies are negative, due in large part because almost no data exists on the success of surgery in this group. Methods 58 prospectively studied sporadic ZES patients (17% of total studied) had negative imaging studies and their surgical outcome was compared to 117 patients with positive imaging results. Results 35 patients had negative imaging in the pre-somatostatin receptor scintigraphy era (SRS) and 23 in the post-SRS era. The image negative patients had long disease histories prior to surgery (mean±SEM, from onset=7.9±1[range −0.25-35 yrs]) and 25% were followed ≥2yrs from diagnosis. At surgery, gastrinoma was found in 57/58 patients (98%). Tumors were small (mean=0.8cm, 60% < 1 cm). The most common primary sites were: duodenal 64%, pancreatic 17%, and lymph node (LN)(10%). 50% had a primary only, 41% primary + LN, and 7% had liver metastases. 35/58(60%) were cured immediately postoperatively and at last follow-up [mean-9.4yrs, range 0.2-22yrs], 27 patients (46%) remained cured. During follow-up 3 patients died, each was found to have liver metastases at surgery. In comparison to the image positive patients, those with negative imaging had lower preop fasting gastrin levels; a longer delay prior to surgery; more frequently had a small duodenal tumors; less frequently had a pancreatic tumor, multiple tumors or developed a new lesion postoperatively and had a longer survival. Conclusions Imaging negative sporadic ZES patients are not rare even in the post-SRS period. An experienced surgeon can find gastrinoma in almost every patient (98%) and nearly one-half (46%) are cured, a rate similar to imaging positive tumor patients. Because liver metastases were found in 7%, which may have been caused by a long delay in surgery and all the disease-related deaths occurred in this group, surgery should be routinely undertaken early in ZES patients despite negative imaging studies. PMID:22868363

Probiotics for vulvovaginal candidiasis in non-pregnant women.

PubMed

Xie, Huan Yu; Feng, Dan; Wei, Dong Mei; Mei, Ling; Chen, Hui; Wang, Xun; Fang, Fang

2017-11-23

Vulvovaginal candidiasis (VVC) is estimated to be the second most common form of infection after bacterial vaginosis. The ability of probiotics in maintaining and recovering the normal vaginal microbiota, and their potential ability to resist Candidas give rise to the concept of using probiotics for the treatment of VVC. To assess the effectiveness and safety of probiotics for the treatment of vulvovaginal candidiasis in non-pregnant women. We searched the following databases to October 2017: Sexually Transmitted Infections Cochrane Review Group's Specialized Register, CENTRAL, MEDLINE, Embase and eight other databases. We searched in following international resources: World Health Organization International Clinical Trials Registry Platform, ClinicalTrials.gov, Web of Science and OpenGrey. We checked specialty journals, reference lists of published articles and conference proceedings. We collected information from pharmaceutical companies and experts in the field. Randomized controlled trials (RCT) using probiotics, alone or as adjuvants to conventional antifungal drugs, to treat VVC in non-pregnant women. Trials recruiting women with recurrent VVC, coinfection with other vulvovaginal infections, diabetes mellitus, immunosuppressive disorders or taking immunosuppressant medication were ineligible for inclusion. Probiotics were included if they were made from single or multiple species and in any preparation type/dosage/route of administration. Two review authors independently assessed trials for eligibility and quality and extracted data. We resolved any disagreements through consensus. The quality of the evidence was assessed using the GRADE approach. Ten RCTs (1656 participants) met our inclusion criteria, and pharmaceutical industry funded none of these trials. All trials used probiotics as adjuvant therapy to antifungal drugs. Probiotics increased the rate of short-term clinical cure (risk ratio (RR) 1.14, 95% confidence interval (CI) 1.05 to 1.24, 695 participants, 5 studies, low quality evidence) and mycological cure (RR 1.06, 95% CI 1.02 to 1.10, 969 participants, 7 studies, low quality evidence) and decreased relapse rate at one month (RR 0.34, 95% CI 0.17 to 0.68, 388 participants, 3 studies, very low quality evidence). However, this effect did not translate into a higher frequency of long-term clinical cure (one month after treatment: RR 1.07, 95% CI 0.86 to 1.33, 172 participants, 1 study, very low quality evidence; three months after treatment: RR 1.30, 95% CI 1.00 to 1.70, 172 participants, one study, very low quality evidence) or mycological cure (one month after treatment: RR 1.26, 95% CI 0.93 to 1.71, 627 participants, 3 studies, very low quality evidence; three months after treatment: RR 1.16, 95% CI 1.00 to 1.35, 172 participants, one study, very low quality evidence). Probiotics use did not increase the frequency of serious (RR 0.80, 95% CI 0.22 to 2.94; 440 participants, 2 studies, low quality evidence). We found no eligible RCTs for outcomes as time to first relapse, need for additional treatment at the end of therapy, patient satisfaction and cost effectiveness. Low and very low quality evidence shows that, compared with conventional treatment, the use of probiotics as an adjuvant therapy could increases the rate of short-term clinical and mycological cure and decrease the relapse rate at one month but this did not translate into a higher frequency of long-term clinical or mycological cure. Probiotics use does not seem to increase the frequency of serious or non-serious adverse events. There is a need for well-designed RCTs with standardized methodologies, longer follow-up and larger sample size.

34 CFR Appendix C to Part 682 - Procedures for Curing Violations of the Due Diligence in Collection and Timely Filing of Claims...

Code of Federal Regulations, 2013 CFR

2013-07-01

... 34 Education 4 2013-07-01 2013-07-01 false Procedures for Curing Violations of the Due Diligence... Part 682 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF POSTSECONDARY EDUCATION, DEPARTMENT OF EDUCATION (CONTINUED) FEDERAL FAMILY EDUCATION LOAN (FFEL) PROGRAM Pt...

34 CFR Appendix C to Part 682 - Procedures for Curing Violations of the Due Diligence in Collection and Timely Filing of Claims...

Code of Federal Regulations, 2011 CFR

2011-07-01

... 34 Education 4 2011-07-01 2011-07-01 false Procedures for Curing Violations of the Due Diligence... Part 682 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF POSTSECONDARY EDUCATION, DEPARTMENT OF EDUCATION (CONTINUED) FEDERAL FAMILY EDUCATION LOAN (FFEL) PROGRAM Pt...

34 CFR Appendix C to Part 682 - Procedures for Curing Violations of the Due Diligence in Collection and Timely Filing of Claims...

Code of Federal Regulations, 2012 CFR

2012-07-01

... 34 Education 4 2012-07-01 2012-07-01 false Procedures for Curing Violations of the Due Diligence... Part 682 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF POSTSECONDARY EDUCATION, DEPARTMENT OF EDUCATION (CONTINUED) FEDERAL FAMILY EDUCATION LOAN (FFEL) PROGRAM Pt...

34 CFR Appendix C to Part 682 - Procedures for Curing Violations of the Due Diligence in Collection and Timely Filing of Claims...

Code of Federal Regulations, 2010 CFR

2010-07-01

... 34 Education 3 2010-07-01 2010-07-01 false Procedures for Curing Violations of the Due Diligence... Part 682 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF POSTSECONDARY EDUCATION, DEPARTMENT OF EDUCATION FEDERAL FAMILY EDUCATION LOAN (FFEL) PROGRAM Pt. 682, App. C...

Air-coupled ultrasound: a novel technique for monitoring the curing of thermosetting matrices.

PubMed

Lionetto, Francesca; Tarzia, Antonella; Maffezzoli, Alfonso

2007-07-01

A custom-made, air-coupled ultrasonic device was applied to cure monitoring of thick samples (7-10 mm) of unsaturated polyester resin at room temperature. A key point was the optimization of the experimental setup in order to propagate compression waves during the overall curing reaction by suitable placement of the noncontact transducers, placed on the same side of the test material, in the so-called pitch-catch configuration. The progress of polymerization was monitored through the variation of the time of flight of the propagating longitudinal waves. The exothermic character of the polymerization was taken into account by correcting the measured value of time of flight with that one in air, obtained by sampling the air velocity during the experiment. The air-coupled ultrasonic results were compared with those obtained from conventional contact ultrasonic measurements. The good agreement between the air-coupled ultrasonic results and those obtained by the rheological analysis demonstrated the reliability of air-coupled ultrasound in monitoring the changes of viscoelastic properties at gelation and vitrification. The position of the transducers on the same side of the sample makes this technique suitable for on-line cure monitoring during several composite manufacturing technologies.

Influence of nanofillers on the thermal and mechanical behavior of DGEBA-based adhesives for bonded-in timber connections

NASA Astrophysics Data System (ADS)

Ahmad, Z.; Ansell, M. P.; Smedley, D.

2006-09-01

Results of an experimental investigation into the thermal behavior and mechanical properties of a room-temperature-cured epoxy adhesive (diglycidyl ether of bisphenol A, DGEBA) cross-linked with polyetheramines and filled with different fillers, namely nanosilica, liquid rubber (CTBN), and clay, are reported. The nanosilica and liquid rubber increased the flexural strength and elastic modulus of the adhesive systems; the addition of clay particles raised the elastic modulus significantly, but embrittled the adhesive. Establishing a correct cure time is very important for bonded-in timber structures, as it will affect the bond strength. A study on the effect of cure time on the flexural strength was carried out, from which it follows that the adhesives should be cured for at least 20 days at room temperature. The damping characteristics and the glass-transition temperature of the adhesives were determined by using a dynamic mechanical thermal analysis. The results showed that the filled adhesives had a higher storage modulus, which was in agreement with the elastic moduli determined from static bending tests. The introduction of the fillers increased its glass-transition temperature considerably.

Comparison of three kinds of mid-urethral slings for surgical treatment of female stress urinary incontinence.

PubMed

Chen, Zhong; Chen, Yuan; Du, Guang-Hui; Yuan, Xiao-yi; Wu, Jia; Zeng, Xiao-yong; Hu, Zhi-quan; Cai, Dan; Yang, Wei-min; Ye

2010-01-01

A study was conducted to compare the efficacy and complications of tension-free vaginal tape (TVT), transobturator vaginal tape inside-out TVT-O and transobturator vaginal tape out-inside (TOT) procedures for the surgical treatment of female stress urinary incontinence SUI. This study is a prospective randomized trial involving 187 women with primary SUI; 77 received TVT, 65 received TVT-O, and 45 patients were treated with TVT-O between June 2002 and December 2009. Before the operation, a complete medical history was taken and a gynecologic examination was performed, including subjective symptoms, history and urodynamic studies. Postoperative data included mean operation time, days of hospitalization, postoperative complications and efficacy evaluation. Therapeutic effect was assessed by presence or absence of incontinence when abdominal pressure increased. The history, physical examination and urodynamic studies among the three groups have no significant difference (P>0.05). The total cure rate was 91.4%. The cure rate in TVT, TVT-O and TOT groups were 90.9%, 92.3% and 91.1%, respectively. There was no significant difference (P>0.05). Mean operative time showed no significant difference between TVT-O and TOT groups, but both were significantly shorter than TVT group (26.90±16.80, 20.00±13.50 vs 48.20±21.90). The mean postoperative hospital stay showed no significant difference between TVT and TVT-O groups, but both groups were significantly longer than TOT group. Mean postoperative hospital stay of TVT, TVT-O and TOT were 5.00±2.40 days, 4.00±2.20 days and 2.30±0.80 days, respectively. The complication rate in TVT, TVT-O and TOT groups was 15.60%, 9.20% and 8.90%, respectively. In TVT group, 4 patients experienced bladder perforation, postoperative dysuria or retention occurred in 7 cases and was cured by urethral dilation, hematomas of retropubic space in 1 patient. No bladder injury occurred in TVT-O and TOT group, 3 patients had postoperative dysuria or retention and 3 patients had transient dysfunction of both lower limbs postoperatively in TVT-O group, 2 patients had postoperative dysuria or retention and 2 patients had transient dysfunction of both lower limbs postoperatively in TOT group. The three tension-free urethral suspension techniques have similar efficacy, all of them are safe and effective procedures for the treatment of female SUI. Compared with TVT, TVT-O and TOT are simpler, less invasive and have fewer complications.

Dielectric analysis of depth dependent curing behavior of dental resin composites.

PubMed

Steinhaus, Johannes; Moeginger, Bernhard; Grossgarten, Mandy; Rosentritt, Martin; Hausnerova, Berenika

2014-06-01

The aim of this study is to investigate depth dependent changes of polymerization process and kinetics of visible light-curing (VLC) dental composites in real-time. The measured quantity - "ion viscosity" determined by dielectric analysis (DEA) - provides the depth dependent reaction rate which is correlated to the light intensity available in the corresponding depths derived from light transmission measurements. The ion viscosity curves of two composites (VOCO Arabesk Top and Grandio) were determined during irradiation of 40s with a light-curing unit (LCU) in specimen depths of 0.5/0.75/1.0/1.25/1.5/1.75 and 2.0mm using a dielectric cure analyzer (NETZSCH DEA 231 with Mini IDEX sensors). The thickness dependent light transmission was measured by irradiation composite specimens of various thicknesses on top of a radiometer setup. The shape of the ion viscosity curves depends strongly on the specimen thickness above the sensor. All curves exhibit a range of linear time dependency of the ion viscosity after a certain initiation time. The determined initiation times, the slopes of the linear part of the curves, and the ion viscosities at the end of the irradiation differ significantly with depth within the specimen. The slopes of the ion viscosity curves as well as the light intensity values decrease with depth and fit to the Lambert-Beer law. The corresponding attenuation coefficients are determined for Arabesk Top OA2 to 1.39mm(-1) and 1.48mm(-1), respectively, and for Grandio OA2 with 1.17 and 1.39mm(-1), respectively. For thicknesses exceeding 1.5mm a change in polymerization behavior is observed as the ion viscosity increases subsequent to the linear range indicating some kind of reaction acceleration. The two VLC composites and different specimen thicknesses discriminate significantly in their ion viscosity evolution allowing for a precise characterization of the curing process even with respect to the polymerization mechanism. Copyright © 2014. Published by Elsevier Ltd.

Secondary Intracranial Tumors Following Radiotherapy for Pituitary Adenomas: A Systematic Review

PubMed Central

Yamanaka, Ryuya; Sato, Toshiteru; Hayano, Azusa; Takashima, Yasuo

2017-01-01

Pituitary adenomas are often treated with radiotherapy for the management of tumor progression or recurrence. Despite the improvement in cure rates, patients treated by radiotherapy are at risk of development of secondary malignancies. We conducted a comprehensive literature review of the secondary intracranial tumors that occurred following radiotherapy to pituitary adenomas to obtain clinicopathological characteristics. The analysis included 48 neuroepithelial tumors, 37 meningiomas, and 52 sarcomas which were published between 1959–2017, although data is missing regarding overall survival and type of irradiation in a significant proportion of the reports. The average onset age for the pituitary adenoma was 37.2 ± 14.4 years and the average latency period before the diagnosis of the secondary tumor was 15.2 ± 8.7 years. Radiotherapy was administered in pituitary adenomas at an average dose of 52.0 ± 19.5 Gy. The distribution of pituitary adenomas according to their function was prolactinoma in 10 (7.2%) cases, acromegaly in 37 (27.0%) cases, Cushing disease in 4 (2.9%) cases, PRL+GH in 1 (0.7%) case, non-functioning adenoma in 57 (41.6%) cases. Irradiation technique delivered was lateral opposing field in 23 (16.7%) cases, 3 or 4 field technique in 27 (19.6%) cases, rotation technique in 10 (7.2%) cases, radio surgery in 6 (4.3%) cases. Most of the glioma or sarcoma had been generated after lateral opposing field or 3/4 field technique. Fibrosarcomas were predominant before 1979 (p < 0.0001). The median overall survival time for all neuroepithelial tumors was 11 months (95% confidence intervals (CI), 3–14). Patients with gliomas treated with radiotherapy exhibited a non-significant positive trend with longer overall survival. The median overall survival time for sarcoma cases was 6 months (95% CI, 1.5–9). The median survival time in patients with radiation and/or chemotherapy for sarcomas exhibited a non-significant positive trend with longer overall survival. In patients treated with radiotherapy for pituitary adenomas, the risk of secondary tumor incidence warrants a longer follow up period. Moreover, radiation and/or chemotherapy should be considered in cases of secondary glioma or sarcoma following radiotherapy to the pituitary adenomas. PMID:28786923

Application of Light-cured Dental Adhesive Resin for Mounting Electrodes or Microdialysis Probes in Chronic Experiments

PubMed Central

Okumura, Tetsu; Okanoya, Kazuo; Tani, Jun

2007-01-01

In chronic recording experiments, self-curing dental acrylic resins have been used as a mounting base of electrodes or microdialysis-probes. Since these acrylics do not bond to the bone, screws have been used as anchors. However, in small experimental animals like finches or mouse, their craniums are very fragile and can not successfully hold the anchors. In this report, we propose a new application of light-curing dental resins for mounting base of electrodes or microdialysis probes in chronic experiments. This material allows direct bonding to the cranium. Therefore, anchor screws are not required and surgical field can be reduced considerably. Past experiences show that the bonding effect maintains more than 2 months. Conventional resin's window of time when the materials are pliable and workable is a few minutes. However, the window of working time for these dental adhesives is significantly wider and adjustable. PMID:18997897

The effect of carbon black (CB) loading on curing characteristics and mechanical properties of virgin acrylonitrile butadiene rubber (Nbrv)/recycled acrylonitrile butadiene rubber (Nbrr) blends

NASA Astrophysics Data System (ADS)

Husnan, M. A.; Ismail, H.; Shuib, R. K.

2018-02-01

Recently, the interest of polymer industry researchers have grown rapidly on the use of specific techniques which can reduce cost and utilize rubber waste into the processing form. The increasing of cognizance in environmental matters and the desire to sustain the resources had fortified the practice of recycling waste materials. In this work, the effect of carbon black loading on curing characteristics and mechanical properties of virgin acrylonitrile butadiene rubber/recycled acrylonitrile butadiene rubber (NBRv/NBRr) blends were studied. Cure time (t90), scorch time (tS2) and swelling percentage decreased but minimum torque (ML) and maximum torque (MH) increased with increasing carbon black (CB) loading in the blends. Increasing CB loading also increased tensile strength, tensile modulus (M100), hardness and compression set but decreased elongation at break (Eb) of NBRv/NBRr blends.

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.

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. Copyright © 2010 Elsevier Masson SAS. All rights reserved.

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.

Performance of maleated castor oil based plasticizer on rubber: rheology and curing characteristic studies

NASA Astrophysics Data System (ADS)

Indrajati, I. N.; Dewi, I. R.

2017-07-01

The objective of this study was to evaluate the performance of maleated castor oil (MACO) as plasticizer on natural rubber (NR), ethylene propylene diene monomer (EPDM), and nitrile butadiene rubber (NBR). The parameter studied were involving rheological, curing and swelling properties. The MACOs were prepared by an esterification reaction between castor oil (CO) and maleic anhydride (MAH) with the help of xylene as water entrainer to improve water removal. Resulting oils then applied as a plasticizer in each of those rubbers within a fixed loading of 5 phr. Comparison has been made to evaluate the performance of MACO and conventional plasticizer (paraffinic oil for NR and EPDM, DOP for NBR) on each rubber. Rheology, curing characteristic and swelling of each rubber were studied. The results showed that rubber (NR/EPDM/NBR) plasticized with MACO had given similar flow characteristic to conventional plasticizers. MACO exhibited slow curing, confirmed by higher t90, but the scorch safety was of the same magnitude. MAH loading tended to decrease the flow properties and curing rate, while scorch time (ts2) was independent.

Halogen and LED light curing of composite: temperature increase and Knoop hardness.

PubMed

Schneider, L F; Consani, S; Correr-Sobrinho, L; Correr, A B; Sinhoreti, M A

2006-03-01

This study assessed the Knoop hardness and temperature increase provided by three light curing units when using (1) the manufacturers' recommended times of photo-activation and (2) standardizing total energy density. One halogen--XL2500 (3M/ESPE)--and two light-emitting diode (LED) curing units--Freelight (3M/ESPE) and Ultrablue IS (DMC)--were used. A type-K thermocouple registered the temperature change produced by the composite photo-activation in a mold. Twenty-four hours after the photo-activation procedures, the composite specimens were submitted to a hardness test. Both temperature increase and hardness data were submitted to ANOVA and Tukey's test (5% significance). Using the first set of photo-activation conditions, the halogen unit produced a statistically higher temperature increase than did both LED units, and the Freelight LED resulted in a lower hardness than did the other curing units. When applying the second set of photo-activation conditions, the two LED units produced statistically greater temperature increase than did the halogen unit, whereas there were no statistical differences in hardness among the curing units.

Cure Cycle Design Methodology for Fabricating Reactive Resin Matrix Fiber Reinforced Composites: A Protocol for Producing Void-free Quality Laminates

NASA Technical Reports Server (NTRS)

Hou, Tan-Hung

2014-01-01

For the fabrication of resin matrix fiber reinforced composite laminates, a workable cure cycle (i.e., temperature and pressure profiles as a function of processing time) is needed and is critical for achieving void-free laminate consolidation. Design of such a cure cycle is not trivial, especially when dealing with reactive matrix resins. An empirical "trial and error" approach has been used as common practice in the composite industry. Such an approach is not only costly, but also ineffective at establishing the optimal processing conditions for a specific resin/fiber composite system. In this report, a rational "processing science" based approach is established, and a universal cure cycle design protocol is proposed. Following this protocol, a workable and optimal cure cycle can be readily and rationally designed for most reactive resin systems in a cost effective way. This design protocol has been validated through experimental studies of several reactive polyimide composites for a wide spectrum of usage that has been documented in the previous publications.

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.

[Application of individual light-curing resin tray as edge plastic material in complete denture modulo].

PubMed

Chai, Mei; Tang, Xuyan; Liang, Guangku

2015-12-01

To investigate clinical effect of individual light-curing resin tray as edge plastic material in complete denture modulo.
 A total of 30 patients with poor condition for alveolar ridge of mandible were chosen individual tray with individual light-curing resin tray for material edge shaping or traditional individual impression tray for edge shaping cream to produce complete denture. The operability, questionnaire about denture retention, comfort, mucosal cases and chewing function in the process of shaping the edge were investigated three months later after wearing dentures.
 There was no significant difference in retention, comfort, mucosa and the chewing function between the two mandibular denture impression methods. However, the patients with individual light-curing resin tray as edge shaping material felt better in the process than that in the patients with die-cream as the edge shaping material (P<0.05). Furthermore, the manipulation with individual light-curing resin tray as edge shaping material is easy for doctor.
 Although the clinical effect of Individual light-curing resin tray material as the edge shaping material is equal to that of impression cream, it saves time and human resource. Moreover, it is more acceptable for the patients and thus it can be spread in clinics.

Population-level cure of colorectal cancer in Malta: An analysis of patients diagnosed between 1995 and 2004.

PubMed

Gauci, Dorothy; Allemani, Claudia; Woods, Laura

2016-06-01

The aim of this study was to estimate the population-level 'cure' of Maltese colorectal cancer patients diagnosed between 1995 and 2004, and to estimate the median survival time for the 'uncured' patients. Analysis was conducted on 1470 cases registered by the Malta National Cancer Register between 1995 and 2004 and followed up to end of 2010. The mean age of the patients was 66.4 (95%CI 65.8-67.1), and the number of men and women were equal. Background mortality for 1995-2010 was extracted from publicly available life tables. A mixture model with Weibull survival distribution and identity link was used to model 'cure'. The overall 'cured' proportion for the patients diagnosed in 1995-1999 was 45.3% (95%CI 40.2-50.5) while the 'cured' proportion for the patients diagnosed in 2000-2004 was 52.3% (95%CI 47.2-57.5). Median survival time for the 'uncured' patients increased in the second calendar period from 1.25 years (95%CI 1.04-1.45) to 1.42 years (95%CI 1.15-1.76). In Malta, as in the rest of Europe, improvements have been made in short- and long-term survival over the 15-year period under study. To continue this improvement, differences by age that still persist must be investigated and efforts focused to reduce any gaps between Malta and other European countries. Copyright © 2016 Elsevier Ltd. All rights reserved.

Italian cancer figures, report 2014: Prevalence and cure of cancer in Italy.

PubMed

2014-01-01

This Report intends to estimate the total number of people still alive in 2010 after cancer diagnosis in Italy, regardless of the time since diagnosis, and to project these estimates to 2015. This study is also aimed to estimate the number of already cured cancer patients, whose mortality rates have become undistinguishable from that of the general population of the same age and sex. The study took advantage of the information from the AIRTUM database, which included 29 Cancer Registries (covering 21 million people, 35% of the Italian population). A total of 1,624,533 cancer cases diagnosed between 1976 and 2009 contributed to the study. For each registry, the observed prevalence was calculated. Prevalence for lengths of time exceeding the maximum duration of the registration and of the complete prevalence were derived by applying an estimated correction factor, the completeness index. This index was estimated by means of statistical regression models using cancer incidence and survival data available in registries with 18 years of observation or more. For 50 types or combinations of neoplasms, complete prevalence was estimated at 1.1.2010 as an absolute number and as a proportion per 100,000 inhabitants by sex, age group, area of residence, and years since diagnosis. Projections of complete prevalence for 1.1.2015 were computed under the assumption of a linear trend of the complete prevalence observed until 2010. Validated mixture cure models were used to estimate: the cure fraction, that is the proportion of patients who, starting from the time of diagnosis, are expected to reach the same mortality rate of the general population; the conditional relative survival (CRS), that is the cumulative probability of surviving some additional years, given that patients already survived a certain number of years; the time to cure, that is the number of years necessary so that conditional survival in the following five years (5-year CRS) exceeds the conventional threshold of 95% (i.e., mortality rates in cancer patients become undistinguishable compared to those of the general population); the proportion of patients already cured, i.e., people alive since a number of years exceeding time to cure. As of 1.1.2010, it was estimated that 2,587,347 people were alive after a cancer diagnosis, corresponding to 4.4% of the Italian population. A relevant geographical heterogeneity emerged, with a prevalence above 5% in northern registries and below 4% in southern areas. Men were 45% of the total (1,154,289) and women 55% (1,433,058). In the population aged 75 years or more, the proportions of prevalent cases were 20% in males and 13% in females, 11% between 60 and 74 years of age in both sexes. Nearly 600,000 Italian women were alive after a breast cancer diagnosis (41% of all women with this neoplasm), followed by women with cancers of the colon rectum (12%), corpus uteri (7%), and thyroid (6%). In men, 26% of prevalent cases (295,624) were patients with prostate cancer, 16% with either bladder or colon rectum cancer. The projections for 1.1.2015 are of three million (3,036,741) people alive after a cancer diagnosis, 4.9% of the Italian population; with a 20% increase for males and 15% for females, compared to 2010. The cure fractions were heterogeneous according to cancer type and age. Estimates obtained as the sum of cure fractions for all cancer types showed that more than 60% of patients diagnosed below the age of 45 years will reach the same mortality rate of the general population. This proportion decreased with increasing age and it was <30% for cancer diagnosed after the age of 74 years. It was observed that 60% of all prevalent cases (1,543,531 people or 2.6% of overall Italian population) had been diagnosed >5 years earlier (long-term survivors). Time to cure (5-year CRS>95%) was reached in <10 years by patients with cancers of the stomach, colon rectum, pancreas, corpus and cervix uteri, brain, and Hodgkin lymphoma. Mortality rates similar to the ones reported by the general population were reached after approximately 20 years for breast and 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. Time to cure was reached by 27% (20% in men and 33% in women) of all people living after a cancer diagnosis, defined as already cured. The study showed a steady increase over time (nearly +3% per year) of prevalent cases in Italy. A quarter of Italian cancer patients alive in 2010 can be considered as already cured. The AIRTUM Report 2014 describes characteristics of cancer patients and former-patients for 50 cancer types or combinations by sex and age. This detailed information promotes the conduction of studies aimed at expanding the current knowledge on the quality of life of these patients during and after the active phase of treatments (prevalence according to health status), on the long-term effects of treatments (in particular for paediatric patients), on the cost profile of cancer patients, and on rare tumours. All these observations have a high potential impact on health planning, clinical practice, and, most of all, patients' perspective.

Superplasticizer Addition to Carbon Fly Ash Geopolymers Activated at Room Temperature.

PubMed

Carabba, Lorenza; Manzi, Stefania; Bignozzi, Maria Chiara

2016-07-18

Present concerns about global warming due to the greenhouse emissions in the atmosphere have pushed the cement industry to research alternatives to ordinary Portland cement (OPC). Geopolymer binder may constitute a possible breakthrough in the development of sustainable materials: understanding the effectiveness and the influences of superplasticizers on geopolymer systems is one of the essential requirements for its large-scale implementation. This study aims to investigate the possibility of using commercially available chemical admixtures designed for OPC concrete, to improve fresh properties of fly ash-based geopolymers and mortars. A special emphasis is laid upon evaluating their influence on mechanical and microstructural characteristics of the hardened material realized under room-temperature curing conditions. Results indicate that the addition of a polycarboxylic ether-based superplasticizer, in the amount of 1.0 wt. % by mass of fly ash, promotes an improvement in workability without compromising the final strength of the hardened material. Moreover, the addition of the polycarboxylic ether- and acrylic-based superplasticizers induces a refinement in the pore structure of hardened mortar leading to a longer water saturation time.

Superplasticizer Addition to Carbon Fly Ash Geopolymers Activated at Room Temperature

PubMed Central

Carabba, Lorenza; Manzi, Stefania; Bignozzi, Maria Chiara

2016-01-01

Present concerns about global warming due to the greenhouse emissions in the atmosphere have pushed the cement industry to research alternatives to ordinary Portland cement (OPC). Geopolymer binder may constitute a possible breakthrough in the development of sustainable materials: understanding the effectiveness and the influences of superplasticizers on geopolymer systems is one of the essential requirements for its large-scale implementation. This study aims to investigate the possibility of using commercially available chemical admixtures designed for OPC concrete, to improve fresh properties of fly ash-based geopolymers and mortars. A special emphasis is laid upon evaluating their influence on mechanical and microstructural characteristics of the hardened material realized under room-temperature curing conditions. Results indicate that the addition of a polycarboxylic ether-based superplasticizer, in the amount of 1.0 wt. % by mass of fly ash, promotes an improvement in workability without compromising the final strength of the hardened material. Moreover, the addition of the polycarboxylic ether- and acrylic-based superplasticizers induces a refinement in the pore structure of hardened mortar leading to a longer water saturation time. PMID:28773707

Systematic review of noninvasive treatments to arrest dentin non-cavitated caries lesions

PubMed Central

de Assunção, Isauremi Vieira; da Costa, Giovanna de Fátima Alves; Borges, Boniek Castillo Dutra

2014-01-01

AIM: To systematically review the literature on the efficacy of noninvasive methods of arresting the progression of non-cavitated occlusal carious lesions in dentin. METHODS: The Medline/PubMed, LILACS, SciELO and Scopus databases were searched to identify relevant publications through to November 2013. Only clinical trials evaluating the ability of noninvasive methods to arrest the progression of occlusal non-cavitated carious lesions in dentin were included. Screening, data extraction and quality assessment were conducted independently and in duplicate. RESULTS: Of 167 citations identified, nine full text articles were screened and five were included in the analysis. All papers reported on occlusal fissure sealing using a self-curing glass ionomer (n = 1) or resin-based (n = 4) sealant. Only the use of resin-based sealant to obliterate occlusal fissures arrested the progression of non-cavitated occlusal carious lesions in dentin. CONCLUSION: Occlusal fissure sealing with a resin-based sealant may arrest the progression of non-cavitated occlusal dentinal caries. Further clinical trials with longer follow-up times should be performed to increase scientific evidence. PMID:24868513

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.

A class of semiparametric cure models with current status data.

PubMed

Diao, Guoqing; Yuan, Ao

2018-02-08

Current status data occur in many biomedical studies where we only know whether the event of interest occurs before or after a particular time point. In practice, some subjects may never experience the event of interest, i.e., a certain fraction of the population is cured or is not susceptible to the event of interest. We consider a class of semiparametric transformation cure models for current status data with a survival fraction. This class includes both the proportional hazards and the proportional odds cure models as two special cases. We develop efficient likelihood-based estimation and inference procedures. We show that the maximum likelihood estimators for the regression coefficients are consistent, asymptotically normal, and asymptotically efficient. Simulation studies demonstrate that the proposed methods perform well in finite samples. For illustration, we provide an application of the models to a study on the calcification of the hydrogel intraocular lenses.

Marination with natural curing ingredients, storage time, and serving temperature effects on the sensory characteristics of forage-finished or commercially-sourced beef roasts.

PubMed

McMurtrie, K E; Kerth, C R; Bratcher, C L; Curtis, P A; Smith, B

2012-03-01

Beef inside round roasts (n=144) were cut from rounds obtained from both forage-finished cattle (n=72) and commercially-sourced beef (n=72). Roasts were portioned to weigh 0.45-0.68kg each. Each roast was then randomly assigned one of the following treatments: control, injected-no cure, or injected-cured. Additionally, roasts were assigned a serving temperature (hot or cold) and storage treatments (0d or 28d post cooking). Roasts from forage-fed beef had a more red interior color and higher shear values, and also retained more brine than commercially-sourced beef (P<0.05). Curing roasts improved TBARS values in roasts served hot and significantly reduced sensory warmed-over and grassy flavors (P<0.05). Marinating forage-finished beef roasts significantly improves tenderness and flavor characteristics. Copyright © 2011 Elsevier Ltd. All rights reserved.

Volatile hydrocarbon profile of Iberian dry-cured hams. A possible tool for authentication of hams according to the fattening diet.

PubMed

Narváez-Rivas, Mónica; Vicario, Isabel M; Alcalde, M Jesús; León-Camacho, Manuel

2010-06-15

The aims of this work were to carry out a comprehensive study of the volatile hydrocarbons of 34 Iberian dry-cured hams and to evaluate the efficiency of these compounds for discriminating hams according to the fattening system: "Montanera" (B) and "Cebo" (C). The samples of hams were obtained by mincing the semimembranosus and semitendinosus muscles from slices of dry-cured ham. The analyses were carried out by gas chromatography-mass spectrometry with a polar capillary column and after a previous extraction by Purge and Trap method. Forty-three volatile hydrocarbons were identified, 26 of them for the first time in Iberian dry-cured ham. Only five compounds showed significant differences between the two types of hams. Among the 33 volatile hydrocarbons, 22 of them allowed a complete discrimination of the two groups of hams according the fattening system.

Cure Kinetics of Benzoxazine/Cycloaliphatic Epoxy Resin by Differential Scanning Calorimetry

NASA Astrophysics Data System (ADS)

Gouni, Sreeja Reddy

Understanding the curing kinetics of a thermoset resin has a significant importance in developing and optimizing curing cycles in various industrial manufacturing processes. This can assist in improving the quality of final product and minimizing the manufacturing-associated costs. One approach towards developing such an understanding is to formulate kinetic models that can be used to optimize curing time and temperature to reach a full cure state or to determine time to apply pressure in an autoclave process. Various phenomenological reaction models have been used in the literature to successfully predict the kinetic behavior of a thermoset system. The current research work was designed to investigate the cure kinetics of Bisphenol-A based Benzoxazine (BZ-a) and Cycloaliphatic epoxy resin (CER) system under isothermal and nonisothermal conditions by Differential Scanning Calorimetry (DSC). The cure characteristics of BZ-a/CER copolymer systems with 75/25 wt% and 50/50 wt% have been studied and compared to that of pure benzoxazine under nonisothermal conditions. The DSC thermograms exhibited by these BZ-a/CER copolymer systems showed a single exothermic peak, indicating that the reactions between benzoxazine-benzoxazine monomers and benzoxazine-cycloaliphatic epoxy resin were interactive and occurred simultaneously. The Kissinger method and isoconversional methods including Ozawa-Flynn-Wall and Freidman were employed to obtain the activation energy values and determine the nature of the reaction. The cure behavior and the kinetic parameters were determined by adopting a single step autocatalytic model based on Kamal and Sourour phenomenological reaction model. The model was found to suitably describe the cure kinetics of copolymer system prior to the diffusion-control reaction. Analyzing and understanding the thermoset resin system under isothermal conditions is also important since it is the most common practice in the industry. The BZ-a/CER copolymer system with 75/25 wt% ratio which exhibited high glass transition temperature compared to polybenzoxazine was investigated under isothermal conditions. The copolymer system exhibited the maximum reaction rate at an intermediate degree of cure (20 to 40%), indicating that the reaction was autocatalytic. Similar to the nonisothermal cure kinetics, Kamal and Sourour phenomenological reaction model was adopted to determine the kinetic behavior of the system. The theoretical values based on the developed model showed a deviation from the obtained experimental values, which indicated the change in kinetics from a reaction-controlled mechanism to a diffusion-controlled mechanism with increasing reaction conversion. To substantiate the hypothesis, Fournier et al's diffusion factor was introduced into the model, resulting in an agreement between the theoretical and experimental values. The changes in cross-linking density and the glass transition temperature (Tg) with increasing epoxy concentration were investigated under Dynamic Mechanical Analyzer (DMA). The BZ-a/CER copolymer system with the epoxy content of less than 40 wt% exhibited the greatest Tg and cross-linking density compared to benzoxazine homopolymer and other ratios.

Ventricular dilation and electrical dyssynchrony synergistically increase regional mechanical nonuniformity but not mechanical dyssynchrony: a computational model.

PubMed

Kerckhoffs, Roy C P; Omens, Jeffrey H; McCulloch, Andrew D; Mulligan, Lawrence J

2010-07-01

Heart failure (HF) in combination with mechanical dyssynchrony is associated with a high mortality rate. To quantify contractile dysfunction in patients with HF, investigators have proposed several indices of mechanical dyssynchrony, including percentile range of time to peak shortening (WTpeak), circumferential uniformity ratio estimate (CURE), and internal stretch fraction (ISF). The goal of this study was to compare the sensitivity of these indices to 4 major abnormalities responsible for cardiac dysfunction in dyssynchronous HF: dilation, negative inotropy, negative lusitropy, and dyssynchronous activation. All combinations of these 4 major abnormalities were included in 3D computational models of ventricular electromechanics. Compared with a nonfailing heart model, ventricles were dilated, inotropy was reduced, twitch duration was prolonged, and activation sequence was changed from normal to left bundle branch block. In the nonfailing heart, CURE, ISF, and WTpeak were 0.97+/-0.004, 0.010+/-0.002, and 78+/-1 milliseconds, respectively. With dilation alone, CURE decreased 2.0+/-0.07%, ISF increased 58+/-47%, and WTpeak increased 31+/-3%. With dyssynchronous activation alone, CURE decreased 15+/-0.6%, ISF increased 14-fold (+/-3), and WTpeak increased 121+/-4%. With the combination of dilation and dyssynchronous activation, CURE decreased 23+/-0.8%, ISF increased 20-fold (+/-5), and WTpeak increased 147+/-5%. Dilation and left bundle branch block combined synergistically decreased regional cardiac function. CURE and ISF were sensitive to this combination, but WTpeak was not. CURE and ISF also reflected the relative nonuniform distribution of regional work better than WTpeak. These findings might explain why CURE and ISF are better predictors of reverse remodeling in cardiac resynchronization therapy.

Efficacy of oral moxifloxacin for aerobic vaginitis.

PubMed

Wang, C; Han, C; Geng, N; Fan, A; Wang, Y; Yue, Y; Zhang, H; Xue, F

2016-01-01

The purpose of this study was to investigate the therapeutic efficacy of oral moxifloxacin for aerobic vaginitis (AV). We also identified factors that are associated with therapeutic efficacy. This prospective study enrolled general gynecological outpatients at Tianjin Medical University General Hospital between September 2012 and May 2014. Women diagnosed with AV (n = 102) were recruited. All enrolled women were treated with oral moxifloxacin, 400 mg once daily for 6 days (one course). Therapeutic efficacy was evaluated based on microscopic criteria, and cure rates were calculated. Women who were microscopically improved (but not cured) received a second course of therapy. Women classified with microscopic failure were treated using other strategies. Univariate and multivariate logistic regression analysis was used to identify factors that may be associated with a cure after one course of therapy. After one course of therapy, 65.7 % (67/102) of women were cured, 29.4 % (30/102) of women were improved (but not cured), 4.9 % (5/102) of women failed to respond to the therapy. After two courses of therapy, 85.3 % (87/102) of women were cured, 9.8 % (10/102) of women were improved, 4.9 % (5/102) of women failed to respond to the therapy, and clinical improvement was achieved in additional women. In the multivariate logistic regression analysis, women with a baseline vaginal pH value of <5.0 had a 3.5-times higher chance of being cured, compared with those with a baseline vaginal pH value of ≥5.0 (OR, 3.503; 95 % CI, 1.278-9.601). Moxifloxacin is an effective therapeutic option for patients with AV. Most women with AV were cured with one course of moxifloxacin. For those with a higher vaginal pH value of ≥5.0 before treatment, two courses of therapy should be considered.

A comparative evaluation of the marginal adaptation of a thermoplastic resin, a light cured wax and an inlay casting wax on stone dies: An in vitro study.

PubMed

Gopalan, Reji P; Nair, Vivek V; Harshakumar, K; Ravichandran, R; Lylajam, S; Viswambaran, Prasanth

2018-01-01

Different pattern materials do not produce copings with satisfactory, marginal accuracy when used on stone dies at varying time intervals. The purpose of this study was to evaluate and compare the vertical marginal accuracy of patterns formed from three materials, namely, thermoplastic resin, light cured wax and inlay casting wax at three-time intervals of 1, 12, and 24 h. A master die (zirconia abutment mimicking a prepared permanent maxillary central incisor) and metal sleeve (direct metal laser sintering crown #11) were fabricated. A total of 30 stone dies were obtained from the master die. Ten patterns were made each from the three materials and stored off the die at room temperature. The vertical marginal gaps were measured using digital microscope at 1, 12, and 24 h after reseating with gentle finger pressure. The results revealed a significant statistical difference in the marginal adaptation of three materials at all the three-time intervals. Light cured wax was found to be most accurate at all time intervals, followed by thermoplastic resin and inlay casting wax. Furthermore, there was a significant difference between all pairs of materials. The change in vertical marginal gap from 1 to 24 h between thermoplastic resin and light cured wax was not statistically significant. The marginal adaptation of all the three materials used, was well within the acceptable range of 25-70 μm. The resin pattern materials studied revealed significantly less dimensional change than inlay casting wax on storage at 1, 12, and 24 h time intervals. They may be employed in situations where high precision and delayed investing is expected.

Silica-alumina trihydrate filled epoxy castings resistant to arced SF.sub.6

DOEpatents

Chenoweth, Terrence E.; Yeoman, Frederick A.

1978-01-01

A cured, insulating, casting composition, having a coefficient of linear thermal expansion of below about 38 .times. 10.sup.-6 in./in./.degree. C and being resistant to arced sulfur hexafluoride gas, in contact with a metal surface in a sulfur hexafluoride gas environment, is made from hydantoin epoxy resin, anhydride curing agent and a filler combination of fused silica and alumina trihydrate.

Implications of the 21st Century Cures Act for the Behavioral and Social Sciences at the National Institutes of Health

ERIC Educational Resources Information Center

Riley, William T.; Blizinsky, Katherine D.

2017-01-01

The 21st Century Cures Act provides funding for key initiatives relevant to the behavioral and social sciences and includes administrative provisions that facilitate health research and increase the privacy protections of research participants. At about the same time as the passage of the Act, the National Institutes of Health Office of Behavioral…

Post-Treatment Follow-Up Study of Abdominal Cystic Echinococcosis in Tibetan Communities of Northwest Sichuan Province, China

PubMed Central

Li, Tiaoying; Ito, Akira; Pengcuo, Renqing; Sako, Yasuhito; Chen, Xingwang; Qiu, Dongchuan; Xiao, Ning; Craig, Philip S.

2011-01-01

Background Human cystic echinococcosis (CE), caused by the larval stage of Echinococcus granulosus, with the liver as the most frequently affected organ, is known to be highly endemic in Tibetan communities of northwest Sichuan Province. Antiparasitic treatment with albendazole remains the primary choice for the great majority of patients in this resource-poor remote area, though surgery is the most common approach for CE therapy that has the potential to remove cysts and lead to complete cure. The current prospective study aimed to assess the effectiveness of community based use of cyclic albendazole treatment in Tibetan CE cases, and concurrently monitor the changes of serum specific antibody levels during treatment. Methodology/Principal Findings Ultrasonography was applied for diagnosis and follow-up of CE cases after cyclic albendazole treatment in Tibetan communities of Sichuan Province during 2006 to 2008, and serum specific IgG antibody levels against Echinococcus granulosus recombinant antigen B in ELISA was concurrently monitored in these cases. A total of 196 CE cases were identified by ultrasound, of which 37 (18.9%) showed evidence of spontaneous healing/involution of hepatic cyst(s) with CE4 or CE5 presentations. Of 49 enrolled CE cases for treatment follow-up, 32.7% (16) were considered to be cured based on B-ultrasound after 6 months to 30 months regular albendazole treatment, 49.0% (24) were improved, 14.3% (7) remained unchanged, and 4.1% (2) became aggravated. In general, patients with CE2 type cysts (daughter cysts present) needed a longer treatment course for cure (26.4 months), compared to cases with CE1 (univesicular cysts) (20.4 months) or CE3 type (detached cyst membrane or partial degeneration of daughter cysts) (9 months). In addition, the curative duration was longer in patients with large (>10 cm) cysts (22.3 months), compared to cases with medium (5–10 cm) cysts (17.3 months) or patients with small (<5 cm) cysts (6 months). At diagnosis, seven (53.8%) of 13 cases with CE1 type cysts without any previous intervention showed negative specific IgG antibody response to E. granulosus recombinant antigen B (rAgB). However, following 3 months to 18 months albendazole therapy, six of these 7 initially seronegative CE1 cases sero-converted to be specific IgG antibody positive, and concurrently ultrasound scan showed that cysts changed to CE3a from CE1 type in all the six CE cases. Two major profiles of serum specific IgG antibody dynamics during albendazole treatment were apparent in CE cases: (i) presenting as initial elevation followed by subsequent decline, or (ii) a persistent decline. Despite a decline, however, specific antibody levels remained positive in most improved or cured CE cases. Conclusions This was the first attempt to follow up community-screened cystic echinococcosis patients after albendazole therapy using ultrasonography and serology in an endemic Tibetan region. Cyclic albendazole treatment proved to be effective in the great majority of CE cases in this resource-poor area, but periodic abdominal ultrasound examination was necessary to guide appropriate treatment. Oral albendazole for over 18 months was more likely to result in CE cure. Poor drug compliance resulted in less good outcomes. Serology with recombinant antigen B could provide additional limited information about the effectiveness of albendazole in CE cases. Post-treatment positive specific IgG antibody seroconversion, in initially seronegative, CE1 patients was considered a good indication for positive therapeutic efficacy of albendazole. PMID:22039558

Color Stability of Heat-cure Acrylic Resin Subjected to Simulated Short-term Immersion in Fast-acting Denture Cleansers.

PubMed

Lohitha, K; Prakash, M; Gopinadh, A; Sai Sankar, A J; Sandeep, C H; Sreedevi, B

2016-01-01

Regular usage of denture cleansers is recommended in complete denture wearers for effective plaque control, and these cleansers alter the physical properties of acrylic resin over a period of time. Thus, an in vitro study was carried out to assess the effect of denture cleansers on the color stability of heat-cure denture base resin. The aim of the present study was to evaluate the effect of commercially available fast-acting denture cleansers on the color stability of heat-cure denture base resin at different time intervals. Thirty-six heat-cure acrylic resin (Ivoclar Triplex Hot-V) specimens are randomly allocated into four groups - Group A (distilled water as control); Group B (polident - 3 min); Group C (fixodent scope plus); and Group D (stain away plus) comprising of nine samples each. After recording the baseline values, the specimens were immersed in their respective cleansing solutions for a prescribed time interval. This procedure was repeated daily, and the color change (ΔE) was evaluated after 90 and 180 days interval using a colorimeter in a standard "Commission International de l'Eclairage" color system. Paired t -test and Dunnett's T3 test. All the groups exhibited a variable color change (ΔE) for an immersion period of 90 days. However, significant color differences ( P = 0.001) were noticed among the test groups after 180 days. The color change of denture base resin was greater for Group D followed by Groups B, C, and A respectively after 180 days of immersion. The ΔE values of all test groups increased with time.

When to start paediatric testing of the adult HIV cure research agenda?

PubMed

Shah, Seema K

2017-02-01

Ethical guidelines recommend that experimental interventions should be tested in adults first before they are tested and approved in children. Some challenge this paradigm, however, and recommend initiating paediatric testing after preliminary safety testing in adults in certain cases. For instance, commentators have argued for accelerated testing of HIV vaccines in children. Additionally, HIV cure research on the use of very early therapy (VET) in infants, prompted in part by the Mississippi baby case, is one example of a strategy that is currently being tested in infants before it has been well tested in adults. Because infants' immune systems are still developing, the timing of HIV transmission is easier to identify in infants than in adults, and infants who receive VET might never develop the viral reservoirs that make HIV so difficult to eradicate, infants may be uniquely situated to achieve HIV cure or sustained viral remission. Several commentators have now argued for earlier initiation of HIV cure interventions other than (or in addition to) VET in children. HIV cure research is therefore a good case for re-examining the important question of when to initiate paediatric research. I will argue that, despite the potential for HIV cure research to benefit children and the scientific value of involving children in this research, the HIV cure agenda should not accelerate the involvement of children for the following reasons: HIV cure research is highly speculative, risky, aimed at combination approaches and does not compare favourably with the available alternatives. I conclude by drawing general implications for the initiation of paediatric testing, including that interventions that have to be used in combination with others and cures for chronic diseases may not be valuable enough to justify early paediatric testing. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

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.

Effect of air-drying time of single-application self-etch adhesives on dentin bond strength.

PubMed

Chiba, Yasushi; Yamaguchi, Kanako; Miyazaki, Masashi; Tsubota, Keishi; Takamizawa, Toshiki; Moore, B Keith

2006-01-01

This study examined the effect of air-drying time of adhesives on the dentin bond strength of several single-application self-etch adhesive systems. The adhesive/resin composite combinations used were: Adper Prompt L-Pop/Filtek Z250 (AP), Clearfil Tri-S Bond/Clearfil AP-X (CT), Fluoro Bond Shake One/Beautifil (FB), G-Bond/Gradia Direct (GB) and One-Up Bond F Plus/Palfique Estelite (OF). Bovine mandibular incisors were mounted in self-curing resin and wet ground with #600 SiC to expose labial dentin. Adhesives were applied according to each manufacturer's instructions followed by air-drying time for 0 (without air-drying), 5 and 10 seconds. After light irradiation of the adhesives, the resin composites were condensed into a mold (phi4x2 mm) and polymerized. Ten samples per test group were stored in 37 degrees C distilled water for 24 hours; they were then shear tested at a crosshead speed of 1.0 mm/minute. One-way ANOVA followed by Tukey's HSD tests (alpha = 0.05) were done. FE-SEM observations of the resin/dentin interface were also conducted. Dentin bond strength varied with the different air drying times and ranged from 5.8 +/- 2.4 to 13.9 +/- 2.8 MPa for AP, 4.9 +/- 1.5 to 17.1 +/- 2.3 MPa for CT, 7.9 +/- 2.8 to 13.8 +/- 2.4 MPa for FB, 3.7 +/- 1.4 to 13.4 +/- 1.2 MPa for GB and 4.6 +/- 2.1 to 13.7 +/- 2.6 MPa for OF. With longer air drying of adhesives, no significant changes in bond strengths were found for the systems used except for OF. Significantly lower bond strengths were obtained for the 10-second air-drying group for OF. From FE-SEM observations, gaps between the cured adhesive and resin composites were observed for the specimens without the air drying of adhesives except for OF. The data suggests that, with four of the single-application self-etch adhesive systems, air drying is essential to obtain adequate dentin bond strengths, but increased drying time does not significantly influence bond strength. For the other system studied, the bond strength of the non-air dried group was not significantly different from the five second drying time, but prolonged drying was very detrimental to bond strength. For all five of the systems studied, a five-second air-drying time appeared to be appropriate.

Treatment Outcome of Severe Acute Malnutrition Cases at the Tamale Teaching Hospital

PubMed Central

Saaka, Mahama; Osman, Shaibu Mohammed; Amponsem, Anthony; Ziem, Juventus B.; Abdul-Mumin, Alhassan; Akanbong, Prosper; Yirkyio, Ernestina; Yakubu, Eliasu

2015-01-01

Objective. This study investigated the treatment outcomes and determinant factors likely to be associated with recovery rate. Methods. A retrospective chart review (RCR) was performed on 348 patients who were enrolled in the outpatient care (OPC) during the study period. Results. Of the 348 cases, 33.6% recovered (having MUAC ≥125 mm), 49.1% defaulted, and 11.5% transferred to other OPC units to continue with treatment. There were 187 (53.7%) males and 161 (46.3%) females with severe malnutrition. The average weight gain rate was 28 g/kg/day. Controlling for other factors, patients who completed the treatment plan had 3.2 times higher probability of recovery from severe acute malnutrition (SAM) as compared to patients who defaulted (adjusted odds ratio (AOR) = 3.2, 95% CI = 1.9, 5.3, and p < 0.001). The children aged 24–59 months had 5.8 times higher probability of recovery from SAM as compared to children aged 6–11 months (AOR = 5.8, 95% CI = 2.5, 10.6, and p < 0.001). Conclusions. Cure rate was low and the default rate was quite high. Children who were diagnosed as having marasmus on admission stayed longer before recovery than their kwashiorkor counterparts. Younger children were of greater risk of nonrecovery. PMID:26064678

Osteoconductive Amine-Functionalized Graphene-Poly(methyl methacrylate) Bone Cement Composite with Controlled Exothermic Polymerization.

PubMed

Sharma, Rakesh; Kapusetti, Govinda; Bhong, Sayali Yashwant; Roy, Partha; Singh, Santosh Kumar; Singh, Shikha; Balavigneswaran, Chelladurai Karthikeyan; Mahato, Kaushal Kumar; Ray, Biswajit; Maiti, Pralay; Misra, Nira

2017-09-20

Bone cement has found extensive usage in joint arthroplasty over the last 50 years; still, the development of bone cement with essential properties such as high fatigue resistance, lower exothermic temperature, and bioactivity has been an unsolved problem. In our present work, we have addressed all of the mentioned shortcomings of bone cement by reinforcing it with graphene (GR), graphene oxide (GO), and surface-modified amino graphene (AG) fillers. These nanocomposites have shown hypsochromic shifts, suggesting strong interactions between the filler material and the polymer matrix. AG-based nanohybrids have shown greater osteointegration and lower cytotoxicity compared to other nanohybrids as well as pristine bone cement. They have also reduced oxidative stress on cells, resulting in calcification within 20 days of the implantation of nanohybrids into the rabbits. They have significantly reduced the exothermic curing temperature to body temperature and increased the setting time to facilitate practitioners, suggesting that reaction temperature and settling time can be dynamically controlled by varying the concentration of the filler. Thermal stability and enhanced mechanical properties have been achieved in nanohybrids vis-à-vis pure bone cement. Thus, this newly developed nanocomposite can create natural bonding with bone tissues for improved bioactivity, longer sustainability, and better strength in the prosthesis.

Pulp chamber temperature rise during curing of resin-based composites with different light-curing units.

PubMed

Durey, Kathryn; Santini, Ario; Miletic, Vesna

2008-01-01

The purpose of the present study was to measure the intrapulpal temperature rise occurring during polymerisation of different shades of resin-based composites (RBCs), and two light-emitting diode (LED) units. Seventy non-carious permanent molars, that had been extracted for orthodontic purposes and stored in 2% thymol for not more than four months, were selected. Patient age range was 11-18 years. Standard cavity preparation with standardised remaining dentine thickness and placement of thermocouples (TCs) was prepared using a novel split-tooth technique. Cavities were filled with one of two shades of RBC (A2 and C4, Filtek Z250, 3M ESPE, Seefeld, Germany), and cured with two LED high-intensity units (Elipar Freelight2, 3M ESPE, Seefeld, Germany; Bluephase, Ivoclar Vivadent, Schaan, Liechtenstein) and a conventional halogen light-curing unit (LCU) (Prismetics Lite 2, Dentsply, Weybridge, Surrey, UK) as a control. Pulp temperature rises during bonding [A2 results: H;2.67/0.48:E;5.24/1.32;B;5.99/1.61] were always greater than during RBC curing [A2 results: 2.44/0.63;E3.34/0.70;B3.38/0.60], and these were significant for both LED lights but not for the halogen control, irrespective of shade (Mann-Whitney test: 95% confidence limits). Temperature rises were at times in excess of the values normally quoted as causing irreversible pulp damage. Pulp temperature rises during bonding were higher with the LED lights than with the halogen control. There was no significant difference in temperature rise between the two LED lights when bonding but there was a significant difference between the two LED lights and the halogen control LCUs (Kruskal-Wallis Test: 95% confidence limits). The results support the view that there is a potential risk for heat-induced pulpal injury when light-curing RBCs. The risk is greater during bonding and with high energy, as compared to low-energy output systems. As the extent of tolerable thermal trauma by the pulp tissues is unknown, care and consideration should be given to the choice of LCU and the exposure time when curing RBCs, and especially during bonding.

Vulvovaginitis: screening for and management of trichomoniasis, vulvovaginal candidiasis, and bacterial vaginosis.

PubMed

van Schalkwyk, Julie; Yudin, Mark H

2015-03-01

To review the evidence and provide recommendations on screening for and management of vulvovaginal candidiasis, trichomoniasis, and bacterial vaginosis. OUTCOMES evaluated include the efficacy of antibiotic treatment, cure rates for simple and complicated infections, and the implications of these conditions in pregnancy. Published literature was retrieved through searches of MEDLINE, EMBASE, CINAHL, and The Cochrane Library in June 2013 using appropriate controlled vocabulary (e.g., vaginitis, trichomoniasis, vaginal candidiasis) and key words (bacterial vaginosis, yeast, candidiasis, trichomonas vaginalis, trichomoniasis, vaginitis, treatment). Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies. There were no date limits, but results were limited to English or French language materials. Searches were updated on a regular basis and incorporated in the guideline to May 2014. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology-related agencies, clinical practice guideline collections, and national and international medical specialty societies. The quality of evidence in this document was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care (Table 1). Summary Statements 1. Vulvovaginal candidiasis affects 75% of women at least once. Topical and oral antifungal azole medications are equally effective. (I) 2. Recurrent vulvovaginal candidiasis is defined as 4 or more episodes per year. (II-2) 3. Trichomonas vaginalis is a common non-viral sexually transmitted infection that is best detected by antigen testing using vaginal swabs collected and evaluated by immunoassay or nucleic acid amplification test. (II-2) 4. Cure rates are equal at up to 88% for trichomoniasis treated with oral metronidazole 2 g once or 500 mg twice daily for 7 days. Partner treatment, even without screening, enhances cure rates. (I-A) 5. Current evidence of the efficacy of alternative therapies for bacterial vaginosis (probiotics, vitamin C) is limited. (I) Recommendations 1. Following initial therapy, treatment success of recurrent vulvovaginal candidiasis is enhanced by maintenance of weekly oral fluconazole for up to 6 months. (II-2A) 2. Symptomatic vulvovaginal candidiasis treated with topical azoles may require longer courses of therapy to be resolved. (1-A) 3. Test of cure following treatment of trichomoniasis with oral metronidazole is not recommended. (I-D) 4. Higher-dose therapy may be needed for treatment-resistant cases of trichomoniasis. (I-A) 5. In pregnancy, treatment of symptomatic Trichomonas vaginalis with oral metronidazole is warranted for the prevention of preterm birth. (I-A) 6. Bacterial vaginosis should be diagnosed using either clinical (Amsel's) or laboratory (Gram stain with objective scoring system) criteria. (II-2A) 7. Symptomatic bacterial vaginosis should be treated with oral metronidazole 500 mg twice daily for 7 days. Alternatives include vaginal metronidazole gel and oral or vaginal clindamycin cream. (I-A) 8. Longer courses of therapy for bacterial vaginosis are recommended for women with documented multiple recurrences. (I-A).

The efficacy and safety of oral pharmacokinetically enhanced amoxycillin-clavulanate 2000/125 mg, twice daily, versus oral amoxycillin-clavulanate 1000/125 mg, three times daily, for the treatment of bacterial community-acquired pneumonia in adults.

PubMed

Petitpretz, Patrick; Chidiac, Christian; Soriano, Francisco; Garau, Javier; Stevenson, Katharine; Rouffiac, Elisabeth

2002-08-01

This double-blind, double-dummy, parallel-group study was designed to show that a pharmacokinetically enhanced formulation of oral amoxycillin-clavulanate (16:1, 2000/125 mg), twice daily, is at least as effective clinically and microbiologically as oral amoxycillin-clavulanate 1000/125 mg, three times daily, in the 10 day treatment of community-acquired pneumonia (CAP) in adults. The pharmacokinetically enhanced formulation is designed to provide higher serum concentrations of amoxycillin for a longer period than standard dosing to achieve coverage of Streptococcus pneumoniae isolates with amoxycillin-clavulanic acid minimum inhibitory concentrations (MICs) up to and including 4 mg/l. A total of 344 patients with CAP from 77 centres received amoxycillin-clavulanate 2000/125 mg twice daily for 10 days (169 patients) or amoxycillin-clavulanate 1000/125 mg three times daily for 10 days (175 patients). The most common pathogen isolated was S. pneumoniae (52.3% of patients, amoxycillin-clavulanate 2000/125 mg group; 46.8% of patients, amoxycillin-clavulanate 1000/125 mg group). In the clinical per-protocol (PP) population at test of cure (days 18-39), the clinical success rate in the amoxycillin-clavulanate 2000/125 mg group was at least as good as in the amoxycillin-clavulanate 1000/125 mg group (91.5 and 93.0%, respectively; 95% CI, -8.3, 5.4). The radiological and bacteriological success rates at test of cure for the PP populations were 92.4 and 90.6% in the amoxycillin-clavulanate 2000/125 mg group and 93.9 and 84.4% in the amoxycillin-clavulanate 1000/125 mg group, respectively. The clinical, bacteriological and radiological success rates at the end of therapy (days 11-17) for the PP populations were all over 85%. Both regimens were well tolerated, with no differences in adverse events between the groups. Amoxycillin-clavulanate 2000/125 mg, twice daily, is well tolerated and at least as effective clinically as amoxycillin-clavulanate 1000/125 mg, three times daily, in patients with CAP and may also be appropriate for the treatment of infections due to S. pneumoniae strains with high-level penicillin resistance.

Study of the counts, species and characteristics of the yeast population during the manufacture of dry-cured "lacón". Effect of salt level.

PubMed

Purriños, Laura; García Fontán, María C; Carballo, Javier; Lorenzo, José M

2013-05-01

The aim of this work was to study the yeast population during the manufacture of dry-cured "lacón" (a Spanish traditional meat product) and the effect of the salting time. For this study, six batches of "lacón" were manufactured with three different salting times (LS (3 days of salting), MS (4 days of salting) and HS (5 days of salting)). Yeast counts increased significantly (P < 0.001) during the whole process from 2.60 to 6.37 log cfu/g. An increased length of salting time did not affect yeast counts throughout the manufacture of dry-cured "lacón", although the highest yeast counts were obtained from LS batches. A total of 226 isolates were obtained from dry-cured "lacón" during drying-ripening stage, of which 151 were yeasts and were identified at the species level using molecular techniques. The total of 151 identified yeasts belonged to 4 different genera: Debaryomyces, Candida, Cryptococcus and Rhodotorula. Debaryomyces hansenii was the most abundant species isolated throughout the whole process as much in the interior as in the exterior of the pieces of three salt levels of "lacón" studied, while Candida zeylanoides was only isolated from the interior of MS and HS batches and from the exterior of LS and HS groups, but at lesser proportion than D. hansenii. Copyright © 2012. Published by Elsevier Ltd.

Self-compacting geopolymer concrete-a review

NASA Astrophysics Data System (ADS)

Ukesh Praveen, P.; Srinivasan, K.

2017-11-01

In this construction world, Geopolymer concrete is a special concrete which doesn’t requires the Ordinary Portland Cement and also reduces the emission of carbon-dioxide. The Geopolymer Concrete is made up of industrial by-products (which contains more Silica and Alumina) and activated with the help of Alkaline solution (combination of sodium hydroxide & sodium silicate or potassium hydroxide & potassium silicate). The high viscosity nature of Geopolymer Concrete had the ability to fail due to lack of compaction. In improvising the issue, Self Compacting Geopolymer Concrete has been introduced. The SCGC doesn’t require any additional compaction it will flow and compacted by its own weight. This concrete is made up of industrial by-products like Fly ash, GGBFS and Silica Fume and activated with alkaline solution. The earlier research was mostly on Fly ash based SCGC. In few research works Fly ash was partially replaced with GGBS and Silica Fume. They evaluated the compressive strength of concrete with varying molarities of NaOH; curing time and curing temperature. The flexural behaviour of the concrete also examined. The Fly ash based SCGC was got high compressive strength in heat curing as well as low compressive strength in ambient curing. The presence of GGBS improves the strength in ambient curing. For aiming the high strength in ambient curing Fly ash will be completely replace and examine with different mineral admixtures.

Simulation and Validation of Injection-Compression Filling Stage of Liquid Moulding with Fast Curing Resins

NASA Astrophysics Data System (ADS)

Martin, Ffion A.; Warrior, Nicholas A.; Simacek, Pavel; Advani, Suresh; Hughes, Adrian; Darlington, Roger; Senan, Eissa

2018-03-01

Very short manufacture cycle times are required if continuous carbon fibre and epoxy composite components are to be economically viable solutions for high volume composite production for the automotive industry. Here, a manufacturing process variant of resin transfer moulding (RTM), targets a reduction of in-mould manufacture time by reducing the time to inject and cure components. The process involves two stages; resin injection followed by compression. A flow simulation methodology using an RTM solver for the process has been developed. This paper compares the simulation prediction to experiments performed using industrial equipment. The issues encountered during the manufacturing are included in the simulation and their sensitivity to the process is explored.

Temperature excursions at the pulp-dentin junction during the curing of light-activated dental restorations.

PubMed

Jakubinek, Michael B; O'Neill, Catherine; Felix, Chris; Price, Richard B; White, Mary Anne

2008-11-01

Excessive heat produced during the curing of light-activated dental restorations may injure the dental pulp. The maximum temperature excursion at the pulp-dentin junction provides a means to assess the risk of thermal injury. In this investigation we develop and evaluate a model to simulate temperature increases during light-curing of dental restorations and use it to investigate the influence of several factors on the maximum temperature excursion along the pulp-dentin junction. Finite element method modeling, using COMSOL 3.3a, was employed to simulate temperature distributions in a 2D, axisymmetric model tooth. The necessary parameters were determined from a combination of literature reports and our measurements of enthalpy of polymerization, heat capacity, density, thermal conductivity and reflectance for several dental composites. Results of the model were validated using in vitro experiments. Comparisons with in vitro experiments indicate that the model provides a good approximation of the actual temperature increases. The intensity of the curing light, the curing time and the enthalpy of polymerization of the resin composite were the most important factors. The composite is a good insulator and the greatest risk occurs when using the light to cure the thin layer of bonding resin or in deep restorations that do not have a liner to act as a thermal barrier. The results show the importance of considering temperature increases when developing curing protocols. Furthermore, we suggest methods to minimize the temperature increase and hence the risk of thermal injury. The physical properties measured for several commercial composites may be useful in other studies.

Contribution of a selected fungal population to proteolysis on dry-cured ham.

PubMed

Martín, Alberto; Córdoba, Juan J; Núñez, Félix; Benito, María J; Asensio, Miguel A

2004-07-01

The proteolytic changes taking place in dry-cured hams lead to increases in free amino acids. Such free amino acids not only contribute to flavour, but also serve as precursors of volatile compounds. Several months of ripening time are required to allow the particular flavour to develop. The fungal population allowed to grow on the surface of some types of dry-cured could play a key role on proteolysis, as it has been shown for dry-cured sausages. The purpose of this work was to study the possible contribution of fungi to proteolysis in dry-cured ham. For this, a strain each of non-toxigenic Penicillium chrysogenum (Pg222) and Debaryomyces hansenii (Dh345), selected for their proteolytic activity on myofibrillar proteins, were inoculated as starter cultures. Changes in the high ionic strength-soluble proteins of an external muscle (adductor) revealed in only 6 months higher proteolysis in the inoculated hams when compared to non-inoculated control hams. Proteolytic strains among the wild fungal population on non-inoculated control hams prevented from obtaining similar differences at the end of processing. However, inoculation with Pg222 and Dh345 led to higher levels for most free amino acids at the external muscle in fully dry-cured hams. In addition, the concentration for some of the more polar free amino acids (i.e. Asp, Glu, Ser and Gln) in inoculated hams was higher at external than at internal (biceps femoris) muscles. These promising results deserve further studies to know the impact of a selected fungal population on the volatile compounds and sensory properties of dry-cured ham.

Room Temperature Curing Polymers

DTIC Science & Technology

1977-05-01

diglycidyl esters are low melting solids, they are easily purified by recrystallization . Both diglycidyl adipate and sebacate were prepared in 88...aromatic amine Shell Z (a eutectic mixture of methylene dianiline and m-phenylene- diamine). The Shell Z cured resins had apparent Tg’s near...cooled to 0oC. The white crystals which formed were recrystallized three times from methanol-water (9:1) to yield 248 g (88%) EEW = 125 (Theory 115

Acoustic emission analysis of tooth-composite interfacial debonding.

PubMed

Cho, N Y; Ferracane, J L; Lee, I B

2013-01-01

This study detected tooth-composite interfacial debonding during composite restoration by means of acoustic emission (AE) analysis and investigated the effects of composite properties and adhesives on AE characteristics. The polymerization shrinkage, peak shrinkage rate, flexural modulus, and shrinkage stress of a methacrylate-based universal hybrid, a flowable, and a silorane-based composite were measured. Class I cavities on 49 extracted premolars were restored with 1 of the 3 composites and 1 of the following adhesives: 2 etch-and-rinse adhesives, 2 self-etch adhesives, and an adhesive for the silorane-based composite. AE analysis was done for 2,000 sec during light-curing. The silorane-based composite exhibited the lowest shrinkage (rate), the longest time to peak shrinkage rate, the lowest shrinkage stress, and the fewest AE events. AE events were detected immediately after the beginning of light-curing in most composite-adhesive combinations, but not until 40 sec after light-curing began for the silorane-based composite. AE events were concentrated at the initial stage of curing in self-etch adhesives compared with etch-and-rinse adhesives. Reducing the shrinkage (rate) of composites resulted in reduced shrinkage stress and less debonding, as evidenced by fewer AE events. AE is an effective technique for monitoring, in real time, the debonding kinetics at the tooth-composite interface.

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

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.

Cure characteristics, crosslink density and degree of filler dispersion of kaolin-filled natural rubber compounds in the presence of alkanolamide

NASA Astrophysics Data System (ADS)

Surya, I.; Hayeemasae, N.; Ginting, M.

2018-03-01

The effects of alkanolamide (ALK) addition on cure characteristics, crosslink density and degree of filler dispersion of kaolin-filled natural rubber (NR) compounds were investigated. The kaolin filler was incorporated into NR compounds with a fixed loading, 30.0 phr. The ALK was prepared from Refined Bleached Deodorized Palm Stearin (RBDPS), a waste product of cooking oil production, and diethanolamine. The ALK is an oily material and added into the filled NR compounds as a rubber additive at different loadings, 0.0, 3.0, 5.0 and 7.0. The kaolin-filled NR compounds with and without ALK were vulcanized using a semi-efficient vulcanization system. It was found that ALK decreased the scorch and cure times and improved filler dispersion of the kaolin-filled NR compounds. The higher the ALK loading, the shorter were the scorch and cure times. It was also found that ALK increased the crosslink density of kaolin-filled NR compound up to 5.0 phr of loading. Due to its oily properties, The ALK acted as an internal plasticizer which decreased the minimum torque and improved the degree of kaolin dispersion in NR phases. The higher the ALK loading; the lower the minimum torque and better the filler dispersion.

[Development of visible-light cured FRP denture].

PubMed

Yu, P Y

1990-06-01

Acrylic denture may be fractured easily because it has a relatively poor resistance to stresses of impact, and the thick acrylic denture base also uncomforted to denture wearers. In this study, for improvement of the mechanical properties, the FRP is applied to the denture base, and try to make a thin denture base. Using the visible light-curing system, the laboratory fabrication time is saved dramatically. To develop the visible light-cured FRP denture base, with various combination of matrix resins and reinforcements, the physical properties of FRP plates were investigated first. From the results of the bending test, hardness test, and manipulation considering, the sateen weave's glasscloth was choose as the reinforcement of the prepreg. The matrix resin of Bis-GMA/UDMA/3G at 48/48/4 wt% was determined. The 3 plies glasscloth included FRP plate is 0.8 mm thickness has the maximum bending strength about 50 kgf/mm2, which is about 5 times larger than that of acrylic resin. Succeeding the study of above, the FRP denture base was fabricated by using the 0.8 mm thickness 3 plies included prepreg. This repreg is manufactured in sheet form beforehand, which is ease to manipulate at laboratory. By using the visible light curing system, it is only taken 10 min. to make a FRP denture base. The following procedures of fabricating a FRP denture is the same as metalplate denture. The visible-light cured FRP denture has some advantages such as accuracy of fit, ease of fabrication and manipulation, and only 0.8 mm thickness but has superior strength.

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 χ 2. 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

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. © 2016, The International Biometric Society.

Influence of power density and primer application on polymerization of dual-cured resin cements monitored by ultrasonic measurement.

PubMed

Takubo, Chikako; Yasuda, Genta; Murayama, Ryosuke; Ogura, Yukari; Tonegawa, Motoka; Kurokawa, Hiroyasu; Miyazaki, Masashi

2010-08-01

We used ultrasonic measurements to monitor the influence of power density and primer application on the polymerization reaction of dual-cured resin cements. The ultrasonic equipment comprised a pulser-receiver, transducers, and an oscilloscope. Resin cements were mixed and inserted into a transparent mould, and specimens were placed on the sample stage, onto which the primer, if used, was also applied. Power densities of 0 (no irradiation), 200, or 600 mW cm(-2) were used for curing. The transit time through the cement disk was divided by the specimen thickness to obtain the longitudinal sound velocity. When resin cements were light-irradiated, each curve displayed an initial plateau of approximately 1,500 m s(-1), which rapidly increased to a second plateau of 2,300-2,900 m s(-1). The rate of sound velocity increase was retarded when the cements were light-irradiated at lower power densities, and increased when the primer was applied. The polymerization behaviour of dual-cured resin cements was therefore shown to be affected by the power density of the curing unit and the application of self-etching primer. (c) 2010 The Authors. Journal compilation (c) 2010 Eur J Oral Sci.

LED Curing Lights and Temperature Changes in Different Tooth Sites.

PubMed

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 χ (2). 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.

Surgery in adrenocortical carcinoma: Importance of national cooperation and centralized surgery.

PubMed

Hermsen, Ilse G C; Kerkhofs, Thomas M A; den Butter, Gijsbert; Kievit, Job; van Eijck, Casper H J; Nieveen van Dijkum, Els J M; Haak, Harm R

2012-07-01

The low incidence rate of adrenocortical carcinoma (ACC) requires a multidisciplinary approach in which surgery plays an essential role because complete resection of the primary tumor is the only chance of cure. To improve patient care, insight into operative results within the ACC population is essential. In 2007, a Dutch Adrenal Network Registry was created covering care and outcome of patients treated for ACC in the Netherlands since 1965. Using this database, we performed a study (1) to gain insight into surgical performance in the Netherlands and (2) to compare operative data with international literature. Data on patients treated from 1965 until January 2008 were studied. The following data were collected: age, gender, functionality of the tumor, stage at diagnosis, operative procedure, completeness of surgery, disease recurrence, adjuvant mitotane therapy, and recurrence-free and overall survival (OS). A total of 175 patients were studied, of whom 149 underwent surgery. Patients with complete resection had significantly longer OS times than patients with incomplete resection (P = .010). Patients operated on in a Dutch Adrenal Network center had significantly longer duration of OS in both univariate (P = .011) and multivariate analysis (P = .014). A significantly greater OS was observed for operated stage IV patients compared with nonoperated patients (P = .002). Our data suggest the relevance of national cooperation and centralized surgery in ACC. For selected patients with stage IV disease, surgery can be beneficial in extending survival. On the basis of the retrospective analysis, operative ACC in the Netherlands can and will be improved. Copyright © 2012. Published by Mosby, Inc.

Thermal cure effects on electromechanical properties of conductive wires by direct ink write for 4D printing and soft machines

NASA Astrophysics Data System (ADS)

Mu, Quanyi; Dunn, Conner K.; Wang, Lei; Dunn, Martin L.; Qi, H. Jerry; Wang, Tiejun

2017-04-01

Recent developments in soft materials and 3D printing are promoting the rapid development of novel technologies and concepts, such as 4D printing and soft machines, that in turn require new methods for fabricating conductive materials. Despite the ubiquity of silver nanoparticles (NPs) in the conducting electrodes of printed electronic devices, their potential use in stretchable conductors has not been fully explored in 4D printing and soft machines. This paper studies the effect of thermal cure conditions on conductivity and electro-mechanical behaviors of silver ink by the direct ink write (DIW) printing approach. We found that the electro-mechanical properties of silver wires can be tailored by controlling cure time and cure temperature to achieve conductivity as well as stretchability. For the silver NP ink we used in the experiments, silver wires cured at 80 °C for 10-30 min have conductivity >1% bulk silver, Young’s modulus <100 MPa, yield strain ˜9%, and can retain conductivity up to 300% strain. In addition, under stress controlled cyclic loading/unloading conditions, the resistance of these wires is only about 1.3 times the initial value after the 100th repeat cycle (7.6% maximum strain in the first cycle). Silver wires cured at 120 °C for 10-20 min are more sensitive to strain and have a yield strain of around 6%. These properties indicate that the silver ink can be used to fabricate stretchable electrodes and flex sensors. Using the DIW fabrication method, we printed silver ink patterns on the surface of 3D printed polymer parts, with the future goal of constructing fully 3D printed arbitrarily formed soft and stretchable devices and of applying them to 4D printing. We demonstrated a fully printed functional soft-matter sensor and a circuit element that can be stretched by as much as 45%.

Long-Term Disease-Free Survival of Non-Metastatic Breast Cancer Patients in Iran: A Survival Model with Competing Risks Taking Cure Fraction and Frailty into Account

PubMed

Ghavami, Vahid; Mahmoudi, Mahmood; Rahimi Foroushani, Abbas; Baghishani, Hossein; Homaei Shandiz, Fatemeh; Yaseri, Mehdi

2017-10-26

Introduction: Survival modeling is a very important tool to detect risk factors and provide a basis for health care planning. However, cancer data may have properties leading to distorted results with routine methods. Therefore, this study aimed to cover specific factors (competing risk, cure fraction and heterogeneity) with a real dataset of Iranian breast cancer patients using a competing risk-cure-frailty model. Materials and methods: For this historical cohort study, information for 550 Iranian breast cancer patients who underwent surgery for tumor removal from 2001 to 2007 and were followed up to March 2017, was analyzed using R 3.2 software. Results: In contrast to T-stage and N-stage, hormone receptor status did not have any significant effect on the cure fraction (long-term disease-free survival). However, T-stage, N-stage and hormone receptor status all had a significant effect on short-term disease-free survival so that the hazard of loco-regional relapse or distant metastasis in cases positive for a hormone receptor was only 0.3 times that for their negative hormone receptor counterparts. The likelihood of locoregional relapse in the first quartile of follow up was nearly twice that of other quartiles. The least cumulative incidence of time to locoregional relapse was for cases with a positive hormone receptor, low N stage and low T stage. The effect of frailty term was significant in this study and a model with frailty appeared more appropriate than a model without, based on the Akaike information criterion (AIC); values for the frailty model and one without the frailty parameter were 1370.39 and 1381.46, respectively. Conclusions: The data from this study indicate ae necessity to consider competing risk, cure fraction and heterogeneity in survival modeling. The competing risk-cure-frailty model can cover complex situations with survival data. Creative Commons Attribution License

Treatment of childhood encopresis: a randomized trial comparing three treatment protocols.

PubMed

Borowitz, Stephen M; Cox, Daniel J; Sutphen, James L; Kovatchev, Boris

2002-04-01

To compare short- and long-term effectiveness of three additive treatment protocols in children experiencing chronic encopresis. Children, 6 to 15 years of age, who experienced at least weekly fecal soiling for 6 months or longer were eligible for the study. Children were randomly assigned to a group that received intensive medical therapy (IMT), a group that received intensive medical therapy plus a behavior management program called enhanced toilet training (ETT), or a group that received intensive medical therapy with enhanced toilet training and external anal sphincter electromyographic biofeedback (BF). Data concerning toileting habits were collected for 14 consecutive days before an initial visit, and at 3, 6, and 12 months after initiation of therapy. All data were collected using a computerized voice-mail system that telephoned the families each day. At 12 months, children were classified as significantly improved (reduction in soiling, P < 0.001) or cured ( 0.90, P < 0.001 in each case). Response to treatment during the first 2 weeks of therapy was highly predictive of outcome at 3, 6, and 12 months (P < 0.0001). Children in the ETT group used less laxative medication (P < 0.04) and required fewer treatment contacts (P = 0.08) than children in the IMM group. All three treatments resulted in significant increases in daily bowel movements passed in the toilet and self-initiated toileting, and resulted in decreases in average daily soiling at 3, 6, and 12 months (P < 0.05). Enhanced toilet training is somewhat more effective in treating childhood encopresis than either intensive medical therapy or anal sphincter biofeedback therapy. Although similar total cure rates at 1 year can be expected with these three forms of therapy, enhanced toilet training results in statistically significant decreases in the daily frequency of soiling for the greatest number of children.

Preparation and properties of optically transparent, pressure-cured poly(methyl methacrylate) composites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weaver, K.D.

The objective of this work was to develop optically transparent glass fiber reinforced poly(methyl methacrylate) composites by matching the refractive index of the glass fiber to that of the PMMA matrix. A pressure curing process [65[degrees]C under 6.9 MPa N[sub 2] for 18 hrs] is described for preparing composites 10 [times] 15 [times] 0.6 cm which typically contain [approximately]10 vol% of 13[mu]m diameter fiber and have 84% optical transmission (92% maximum for PMMA) at 600 nm and 25[degrees]C. Evidence is presented relating the interfacial bonding strength and the optical transmission of transparent, glass fiber (13 [mu]m) reinforced PMMA composites. Themore » temperature dependent (20-50[degrees]C) transmission of composites containing uncoated fiber and fiber coated with divinyltetramethyl disilazane or 3-(trimethoxysilyl)propyl methacrylate was found to decrease in the same order as the bond strength of the PMMA/fiber interface, namely, silane coated, disilazane coated, and uncoated fiber. By using annealed (1 1/3 hours/400[degrees]C) 13 [mu]m BK10 fiber, these pressure-cured composites function optically as ultra-violet Solid Matrix Christiansen Filters. The composite filters have an optical transmission of 51% at 51[degrees]C and 305 nm with a half-height bandwidth of only 28 nm, which is more wavelength selective than reported solid matrix Christiansen filters and typical band pass filters. While the density (1.18-1.19 g/ml at 23[degrees]C) and coefficient of thermal expansion (9.9[times]10[sup [minus]5] K[sup [minus]1]) show no change at these curing conditions, the minimum stress to craze (33 wt% toluene in isobutyl acetate) for pressure-cured [65[degrees]C/6.9 MPa N[sub 2]/18 hrs] PMMA was found to be improved.« less

In Situ Poling and Imidization of Amorphous Piezoelectric Polyimides

NASA Technical Reports Server (NTRS)

Park, Cheol; Ounaies, Zoubeida; Wise, Kristopher E.; Harrison, Joycelyn S.; Bushnell, Dennis M. (Technical Monitor)

2002-01-01

An amorphous piezoelectric polyimide containing polar functional groups has been developed using a combination of experimental and molecular modeling for potential use in high temperature applications. This amorphous polyimide, (Beta-CN)APB/ODPA, has exhibited good thermal stability and piezoelectric response at temperatures up to 150C. Density functional calculations predicted that a partially cured amic acid (open imide ring) possesses a dipole moment four times larger than the fully imidized closed ring. In situ poling and imidization of the partially cured (Beta-CN)APB/ODPA, was studied in an attempt to maximize the degree of dipolar orientation and the resultant piezoelectric response. A positive corona poling was used to minimize localized arcing during poling and to allow use of higher poling fields without dielectric breakdown. The dielectric relaxation strength, remanent polarization, and piezoelectric response were evaluated as a function of the poling profile. The partially cured, corona poled polymers exhibited higher dielectric relaxation strength (delta varepsilon), remanent polarization (Pr) and piezoelectric strain coefficient (d33) than the fully cured, conventionally poled ones.

Characterisation and detection of spoilage mould responsible for black spot in dry-cured fermented sausages.

PubMed

Lozano-Ojalvo, Daniel; Rodríguez, Alicia; Cordero, Mirian; Bernáldez, Victoria; Reyes-Prieto, Mariana; Córdoba, Juan J

2015-02-01

Moulds responsible for black spot spoilage of dry-cured fermented sausages were characterised. For this purpose, samples were taken from those dry-cured fermented sausages which showed black spot alteration. Most of the mould strains were first tentatively identified as Penicillium spp. due to their morphological characteristics in different culture conditions, with one strain as Cladosporium sp. The Cladosporium strain was the only one which provoked blackening in culture media. This strain was further characterised by sequencing of ITS1-5.8S-ITS2 rRNA and β-tubulin genes. This mould strain was able to reproduce black spot formation in dry-cured fermented sausage 'salchichón' throughout the ripening process. In addition, a specific and sensitive real-time PCR method was also developed to detect Cladosporium oxysporum responsible for the black spot formation in sausages. This method could be of great interest for the meat industry to detect samples contaminated with this mould before spoilage of product avoiding economic losses for this sector.

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. © The Author(s) 2013.

Radiation curing: Science and technology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pappas, S.P.

1992-01-01

The science and technology of radiation curing have progressed substantially within the last 20 years. Nevertheless, radiation-curable compositions typically command relatively small shares in many of their competitive markets. This situation signifies that potential advantages of radiation curing are not generally perceived to overcome their limitations. An important objective of this book is to address this issue, within the scope of the subjects offered, by providing the present state of knowledge and by identifying the directions and challenges for future studies. The first chapter introduces radiation curing. Chapter 2 offers the first systematic presentation of inorganic and organometallic photoinitiators. Chaptersmore » 3 and 4 present the analytical techniques of photocalorimetry and real-time infrared spectroscopy, respectively. Recent advances in resin technology are offered in Chapters 5 and 6, which constitute the first comprehensive accounts of (meth)acrylated silicones and vinyl ethers, respectively. Radiation-curable coatings, printing inks, and adhesives are discussed in Chapters 7-9, respectively. Chapter 10 offers a discussion on photopolymer imaging systems.« less

A new validated HPLC-FLD method for detecting ochratoxin A in dry-cured meat and in blue cheese.

PubMed

Dall'asta, C; Galaverna, G; De Dea Lindner, J; Virgili, R; Neviani, E; Dossena, A

2007-09-01

In the present study, a fast and sensitive method for the quantification of ochratoxin A in two lipidicproteic food matrices has been developed. In particular, the sample preparation procedure has been optimized for dry-cured meat products and blue cheeses and tested for several validation parameters (LOD, LOQ, recovery, repeatability and within-laboratory precision). The procedure has been then applied to several dry-cured meat products and blue cheeses from the market.Ochratoxin A has been occasionally found in dry-cured and smoked ham from the market and the contamination occurred both in the outer and in the inner part of the products. Concerning the blue cheese, the occurrence of ochratoxin A is reported for the first time: OTA was occasionally found at low levels (0.1-3 μg/kg) in commercial samples of Roquefort from France and Gorgonzola from Italy, opening a new issue for risk assessment and quality control.

Photopolymerizable liquid encapsulants for microelectronic devices

NASA Astrophysics Data System (ADS)

Baikerikar, Kiran K.

2000-10-01

Plastic encapsulated microelectronic devices consist of a silicon chip that is physically attached to a leadframe, electrically interconnected to input-output leads, and molded in a plastic that is in direct contact with the chip, leadframe, and interconnects. The plastic is often referred to as the molding compound, and is used to protect the chip from adverse mechanical, thermal, chemical, and electrical environments. Encapsulation of microelectronic devices is typically accomplished using a transfer molding process in which the molding compound is cured by heat. Most transfer molding processes suffer from significant problems arising from the high operating temperatures and pressures required to fill the mold. These aspects of the current process can lead to thermal stresses, incomplete mold filling, and wire sweep. In this research, a new strategy for encapsulating microelectronic devices using photopolymerizable liquid encapsulants (PLEs) has been investigated. The PLEs consist of an epoxy novolac-based vinyl ester resin (˜25 wt.%), fused silica filler (70--74 wt.%), and a photoinitiator, thermal initiator, and silane coupling agent. For these encapsulants, the use of light, rather than heat, to initiate the polymerization allows precise control over when the reaction starts, and therefore completely decouples the mold filling and the cure. The low viscosity of the PLEs allows for low operating pressures and minimizes problems associated with wire sweep. In addition, the in-mold cure time for the PLEs is equivalent to the in-mold cure times of current transfer molding compounds. In this thesis, the thermal and mechanical properties, as well as the viscosity and adhesion of photopolymerizable liquid encapsulants, are reported in order to demonstrate that a UV-curable formulation can have the material properties necessary for microelectronic encapsulation. In addition, the effects of the illumination time, postcure time, fused silica loading, and the inclusion of a thermal initiator on the thermal and mechanical properties of the final cured encapsulants have been investigated. The results show that the material properties of the PLEs are the same, if not better, than those exhibited by conventional transfer molding compounds and demonstrate the potential of using PLEs for encapsulating microelectronic devices.

Survivorship analysis when cure is a possibility: a Monte Carlo study.

PubMed

Goldman, A I

1984-01-01

Parametric survivorship analyses of clinical trials commonly involves the assumption of a hazard function constant with time. When the empirical curve obviously levels off, one can modify the hazard function model by use of a Gompertz or Weibull distribution with hazard decreasing over time. Some cancer treatments are thought to cure some patients within a short time of initiation. Then, instead of all patients having the same hazard, decreasing over time, a biologically more appropriate model assumes that an unknown proportion (1 - pi) have constant high risk whereas the remaining proportion (pi) have essentially no risk. This paper discusses the maximum likelihood estimation of pi and the power curves of the likelihood ratio test. Monte Carlo studies provide results for a variety of simulated trials; empirical data illustrate the methods.

Isothermal transitions of a thermosetting system

NASA Technical Reports Server (NTRS)

Gillham, J. K.; Benci, J. A.; Noshay, A.

1974-01-01

A study of the curing reactions of a cycloaliphatic epoxy resin/anhydride system by torsional braid analysis showed the existence of two critical isothermal temperatures - namely, the maximum glass transition temperature of the thermoset system and the glass transition temperature of the material at its gel point. Two rheologically active kinetic transitions occur during isothermal cure which correspond to gelation and vitrification. Three types of isothermal behavior occur. Methods for determining the time to gel and the time to vitrify, and also the two above-mentioned critical isothermal temperatures, have been developed. The time to gel obeyed the Arrhenius relationship, whereas the time to vitrify passed through a minimum. Application of these results to thermosetting systems in general is discussed in terms of the influence of molecular structure on the values of the critical isothermal temperatures.

TVT-Secur mini-sling for stress urinary incontinence: a review of outcomes at 12 months.

PubMed

Walsh, Colin A

2011-09-01

• Synthetic mid-urethral slings (MUSs) are considered the first choice surgical procedure for stress urinary incontinence. Recent publications have raised concerns about the efficacy of third generation single-incision mini-slings. The present paper is a systematic review of studies reporting 12-month outcomes after the TVT-Secur (TVT-S) procedure. • Pubmed/Medline online databases, abstracts from recent International Continence Society and International Urogynecological Association annual scientific meetings and the Clinicaltrials.gov and Controlled-trials.com online trial registries were searched for English-language articles containing the terms 'TVT-Secur', 'TVT Secur' or 'mini-sling'. The primary outcomes were objective and subjective cure rates at 12 months. Secondary outcomes included peri-operative (vaginal perforation, urinary retention, urinary tract infection [UTI]) and postoperative (mesh exposure, de novo overactive bladder (OAB), dyspareunia and return to theatre) complication rates. • Among 1178 women undergoing the TVT-S procedure, from 10 studies, both objective and subjective cure rate at 12 months was 76%, with objective cure significantly higher in women undergoing the 'U-type' approach. Vaginal perforation was a complication in 1.5% of cases, with a 2.4% incidence of mesh exposure in the first year. The incidence of de novo OAB symptoms was 10%. Rates of urinary retention (2.3%), UTI (4.4%), dyspareunia (1%) and return to theatre for complications (0.8%) were low. In the first year after a TVT-S procedure 5% of women required repeat continence surgery. • Longer-term studies and randomized comparisons with more established MUSs are required before TVT-S should be routinely used in the surgical treatment of stress urinary incontinence. © 2011 THE AUTHOR. BJU INTERNATIONAL © 2011 BJU INTERNATIONAL.

Efficacy of Controlled Atmosphere Treatments to Manage Arthropod Pests of Dry-Cured Hams

PubMed Central

Hasan, Md. Mahbub; Aikins, Michael J.; Schilling, Wes; Phillips, Thomas W.

2016-01-01

Research here explored the use of controlled atmospheres (CA) for managing arthropod pests that infest dry-cured hams. Experiments were conducted with low oxygen (O2) achieved with low pressure under a vacuum, high carbon dioxide (CO2), and ozone (O3). Results showed that both low O2 and high CO2 levels required exposures up to 144 h to kill 100% of all stages of red-legged ham beetle, Necrobia rufipes (De Geer) (Coleoptera: Cleridae) and ham mite Tyrophagus putrescentiae (Schrank) (Sarcoptiformes: Acaridae) at 23 °C. In addition, both low O2 and high CO2 had no significant mortality against the ham beetle and ham mites at short exposures ranging from 12 to 48 h. Ham beetles were more tolerant than ham mites to an atmosphere of 75.1% CO2 and low pressure of 25 mm Hg, which imposed an atmosphere estimated at 0.9% O2. Both low O2 and high CO2 trials indicated that the egg stages of both species were more tolerant than other stages tested, but N. rufipes eggs and pupae were more susceptible than larvae and adults to high concentration ozone treatments. The results indicate that O3 has potential to control ham beetles and ham mites, particularly at ≈166 ppm in just a 24 h exposure period, but O3 is known from other work to have poor penetration ability, thus it may be more difficult to apply effectively than low O2 or high CO2. would be. CA treatment for arthropod pests of dry-cured hams show promise as components of integrated pest management programs after methyl bromide is no longer available for use. PMID:27598209

Short- versus long-duration levofloxacin plus rifampicin for acute staphylococcal prosthetic joint infection managed with implant retention: a randomised clinical trial.

PubMed

Lora-Tamayo, Jaime; Euba, Gorane; Cobo, Javier; Horcajada, Juan Pablo; Soriano, Alex; Sandoval, Enrique; Pigrau, Carles; Benito, Natividad; Falgueras, Luis; Palomino, Julián; Del Toro, María Dolores; Jover-Sáenz, Alfredo; Iribarren, José Antonio; Sánchez-Somolinos, Mar; Ramos, Antonio; Fernández-Sampedro, Marta; Riera, Melchor; Baraia-Etxaburu, Josu Mirena; Ariza, Javier

2016-09-01

Levofloxacin plus rifampicin (L+R) is the treatment of choice for acute staphylococcal prosthetic joint infection (PJI) managed with debridement and implant retention (DAIR). Long courses have been empirically recommended, but some studies have suggested that shorter treatments could be as effective. Our aim was to prove that a short treatment schedule was non-inferior to the standard long schedule. An open-label, multicentre, randomised clinical trial (RCT) was performed. Patients with an early post-surgical or haematogenous staphylococcal PJI, managed with DAIR and initiated on L+R were randomised to receive 8 weeks of treatment (short schedule) versus a long schedule (3 months or 6 months for hip or knee prostheses, respectively). The primary endpoint was cure rate. From 175 eligible patients, 63 were included (52% women; median age, 72 years): 33 patients (52%) received the long schedule and 30 (48%) received the short schedule. There were no differences between the two groups except for a higher rate of polymicrobial infection in the long-schedule group (27% vs. 7%; P = 0.031). Median follow-up was 540 days. In the intention-to-treat analysis, cure rates were 58% and 73% in patients receiving the long and short schedules, respectively (difference -15.7%, 95% CI -39.2% to 7.8%). Forty-four patients (70%) were evaluable per-protocol: cure rates were 95.0% and 91.7% for the long and short schedules, respectively (difference 3.3%, 95% CI -11.7% to 18.3%). This is the first RCT suggesting that 8 weeks of L+R could be non-inferior to longer standard treatments for acute staphylococcal PJI managed with DAIR. Copyright © 2016 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.

Carbon-On-Carbon Manufacturing

NASA Technical Reports Server (NTRS)

Mungas, Gregory S. (Inventor); Buchanan, Larry (Inventor); Banzon, Jr., Jose T. (Inventor)

2017-01-01

The presently disclosed technology relates to carbon-on-carbon (C/C) manufacturing techniques and the resulting C/C products. One aspect of the manufacturing techniques disclosed herein utilizes two distinct curing operations that occur at different times and/or using different temperatures. The resulting C/C products are substantially non-porous, even though the curing operation(s) substantially gasify a liquid carbon-entrained filler material that saturates a carbon fabric that makes up the C/C products.

Surface engineering of ferroelectric polymer for the enhanced electrical performance of organic transistor memory

NASA Astrophysics Data System (ADS)

Kim, Do-Kyung; Lee, Gyu-Jeong; Lee, Jae-Hyun; Kim, Min-Hoi; Bae, Jin-Hyuk

2018-05-01

We suggest a viable surface control method to improve the electrical properties of organic nonvolatile memory transistors. For viable surface control, the surface of the ferroelectric insulator in the memory field-effect transistors was modified using a smooth-contact-curing process. For the modification of the ferroelectric polymer, during the curing of the ferroelectric insulators, the smooth surface of a soft elastomer contacts intimately with the ferroelectric surface. This smooth-contact-curing process reduced the surface roughness of the ferroelectric insulator without degrading its ferroelectric properties. The reduced roughness of the ferroelectric insulator increases the mobility of the organic field-effect transistor by approximately eight times, which results in a high memory on–off ratio and a low-voltage reading operation.

Materials Analysis and Modeling of Underfill Materials.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wyatt, Nicholas B; Chambers, Robert S.

2015-08-01

The thermal-mechanical properties of three potential underfill candidate materials for PBGA applications are characterized and reported. Two of the materials are a formulations developed at Sandia for underfill applications while the third is a commercial product that utilizes a snap-cure chemistry to drastically reduce cure time. Viscoelastic models were calibrated and fit using the property data collected for one of the Sandia formulated materials. Along with the thermal-mechanical analyses performed, a series of simple bi-material strip tests were conducted to comparatively analyze the relative effects of cure and thermal shrinkage amongst the materials under consideration. Finally, current knowledge gaps asmore » well as questions arising from the present study are identified and a path forward presented.« less

Fingolimod

MedlinePlus

... symptoms flare up from time to time) of multiple sclerosis (MS; a disease in which the nerves do ... take your first dose.Fingolimod may help control multiple sclerosis but will not cure it. Do not stop ...

Teriflunomide

MedlinePlus

... symptoms flare up from time to time) of multiple sclerosis (MS; a disease in which the nerves do ... doctor.Teriflunomide may help control the symptoms of multiple sclerosis but does not cure it. Continue to take ...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Janke, C.J.

Electron beam (EB) curing is a technology that promises, in certain applications, to deliver lower cost and higher performance polymer matrix composite (PMC) structures compared to conventional thermal curing processes. PMCs enhance performance by making products lighter, stronger, more durable, and less energy demanding. They are essential in weight- and performance-dominated applications. Affordable PMCs can enhance US economic prosperity and national security. US industry expects rapid implementation of electron beam cured composites in aircraft and aerospace applications as satisfactory properties are demonstrated, and implementation in lower performance applications will likely follow thereafter. In fact, at this time and partly becausemore » of discoveries made in this project, field demonstrations are underway that may result in the first fielded applications of electron beam cured composites. Serious obstacles preventing the widespread use of electron beam cured PMCs in many applications are their relatively poor interfacial properties and resin toughness. The composite shear strength and resin toughness of electron beam cured carbon fiber reinforced epoxy composites were about 25% and 50% lower, respectively, than those of thermally cured composites of similar formulations. The essential purpose of this project was to improve the mechanical properties of electron beam cured, carbon fiber reinforced epoxy composites, with a specific focus on composite shear properties for high performance aerospace applications. Many partners, sponsors, and subcontractors participated in this project. There were four government sponsors from three federal agencies, with the US Department of Energy (DOE) being the principal sponsor. The project was executed by Oak Ridge National Laboratory (ORNL), NASA and Department of Defense (DOD) participants, eleven private CRADA partners, and two subcontractors. A list of key project contacts is provided in Appendix A. In order to properly manage the large project team and properly address the various technical tasks, the CRADA team was organized into integrated project teams (IPT's) with each team focused on specific research areas. Early in the project, the end user partners developed ''exit criteria'', recorded in Appendix B, against which the project's success was to be judged. The project team made several important discoveries. A number of fiber coatings or treatments were developed that improved fiber-matrix adhesion by 40% or more, according to microdebond testing. The effects of dose-time and temperature-time profiles during the cure were investigated, and it was determined that fiber-matrix adhesion is relatively insensitive to the irradiation procedure, but can be elevated appreciably by thermal postcuring. Electron beam curable resin properties were improved substantially, with 80% increase in electron beam 798 resin toughness, and {approx}25% and 50% improvement, respectively, in ultimate tensile strength and ultimate tensile strain vs. earlier generation electron beam curable resins. Additionally, a new resin electron beam 800E was developed with generally good properties, and a very notable 120% improvement in transverse composite tensile strength vs. earlier generation electron beam cured carbon fiber reinforced epoxies. Chemical kinetics studies showed that reaction pathways can be affected by the irradiation parameters, although no consequential effects on material properties have been noted to date. Preliminary thermal kinetics models were developed to predict degree of cure vs. irradiation and thermal parameters. These models are continually being refined and validated. Despite the aforementioned impressive accomplishments, the project team did not fully realize the project objectives. The best methods for improving adhesion were combined with the improved electron beam 3K resin to make prepreg and uni-directional test laminates from which composite properties could be determined. Nevertheless, only minor improvements in the composite shear strength, and moderate improvements in the transverse tensile strength, were achieved. The project team was not satisfied with the laminate quality achieved, and low quality (specifically, high void fraction) laminates will compromise the composite properties. There were several problems with the prepregging and fabrication, many of them related to the use of new fiber treatments.« less

Effect of different photoinitiators and reducing agents on cure efficiency and color stability of resin-based composites using different LED wavelengths.

PubMed

de Oliveira, Dayane Carvalho Ramos Salles; Rocha, Mateus Garcia; Gatti, Alexandre; Correr, Americo Bortolazzo; Ferracane, Jack Liborio; Sinhoret, Mario Alexandre Coelho

2015-12-01

To evaluate the effect of photoinitiators and reducing agents on cure efficiency and color stability of resin-based composites using different LED wavelengths. Model resin-based composites were associated with diphenyl(2,4,6-trimethylbenzoyl) phosphine oxide (TPO), phenylbis(2,4,6-trimethylbenzoyl) phosphine oxide (BAPO) or camphorquinone (CQ) associated with 2-(dimethylamino) ethyl methacrylate (DMAEMA), ethyl 4-(dimethyamino) benzoate (EDMAB) or 4-(N,N-dimethylamino) phenethyl alcohol (DMPOH). A narrow (Smartlite, Dentisply) and a broad spectrum (Bluephase G2, Ivoclar Vivadent) LEDs were used for photo-activation (20 J/cm(2)). Fourier transform infrared spectroscopy (FT-IR) was used to evaluate the cure efficiency for each composite, and CIELab parameters to evaluated color stability (ΔE00) after aging. The UV-vis absorption spectrophotometric analysis of each photoinitiator and reducing agent was determined. Data were analyzed using two-way ANOVA and Tukey's test for multiple comparisons (α=0.05). Higher cure efficiency was found for type-I photoinitiators photo-activated with a broad spectrum light, and for CQ-systems with a narrow band spectrum light, except when combined with an aliphatic amine (DMAEMA). Also, when combined with aromatic amines (EDMAB and DMPOH), similar cure efficiency with both wavelength LEDs was found. TPO had no cure efficiency when light-cured exclusively with a blue narrowband spectrum. CQ-systems presented higher color stability than type-I photoinitiators, especially when combined with DMPOH. After aging, CQ-based composites became more yellow and BAPO and TPO lighter and less yellow. However, CQ-systems presented higher color stability than type-I photoinitiators, as BAPO- and TPO-, despite their higher cure efficiency when photo-activated with corresponding wavelength range. Color matching is initially important, but color change over time will be one of the major reasons for replacing esthetic restorations; despite the less yellowing of these alternative photoinitiators, camphorquinone presented higher color stability. Copyright © 2015 Elsevier Ltd. All rights reserved.

Using a centrifuge for quality control of pre-wetted lightweight aggregate in internally cured concrete

NASA Astrophysics Data System (ADS)

Miller, Albert E.

Early age shrinkage of cementitious systems can result in an increased potential for cracking which can lead to a reduction in service life. Early age shrinkage cracking can be particularly problematic for high strength concretes, which are often specified due to their high strength and low permeability. However, these high strength concretes frequently exhibit a reduction in the internal relative humidity (RH) due to the hydration reaction (chemical shrinkage) and self-desiccation which results in a bulk shrinkage, termed autogenous shrinkage, which is substantial at early ages. Due to the low permeability of these concretes, standard external curing is not always efficient in addressing this reduction in internal RH since the penetration of water can be limited. Internal curing has been developed to reduce autogenous shrinkage. Internally cured mixtures use internal reservoirs filled with fluid (generally water) that release this fluid at appropriate times to counteract the effects of self-desiccation thereby maintaining a high internal RH. Internally cured concrete is frequently produced in North America using pre-wetted lightweight aggregate. One important aspect associated with preparing quality internally cured concrete is being able to determine the absorbed moisture and surface moisture associated with the lightweight aggregate which enables aggregate moisture corrections to be made for the concrete mixture. This thesis represents work performed to develop a test method using a centrifuge to determine the moisture state of pre-wetted fine lightweight aggregate. The results of the test method are then used in a series of worksheets that were developed to assist field technicians when performing the tests and applying the results to a mixture design. Additionally, research was performed on superabsorbent polymers to assess their ability to be used as an internal curing reservoir.

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

Stakeholder Engagement in HIV Cure Research: Lessons Learned from Other HIV Interventions and the Way Forward

PubMed Central

Chu, Carissa; Ananworanich, Jintanat; Excler, Jean-Louis; Tucker, Joseph D.

2015-01-01

Abstract Clinical and basic science advances have raised considerable hope for achieving an HIV cure by accelerating research. This research is dominated primarily by issues about the nature and design of current and future clinical trials. Stakeholder engagement for HIV cure remains in its early stages. Our analysis examines timing and mechanisms of historical stakeholder engagement in other HIV research areas for HIV-uninfected individuals [vaccine development and pre-exposure prophylaxis (PrEP)], and HIV-infected individuals (treatment as prevention, prevention of mother-to-child transmission, and treatment of acute HIV infection) and articulate a plan for HIV cure stakeholder engagement. The experience from HIV vaccine development shows that early engagement of stakeholders helped manage expectations, mitigating the failure of several vaccine trials, while paving the way for subsequent trials. The relatively late engagement of HIV stakeholders in PrEP research may partly explain some of the implementation challenges. The treatment-related stakeholder engagement was strong and community-led from the onset and helped translation from research to implementation. We outline five steps to initiate and sustain stakeholder engagement in HIV cure research and conclude that stakeholder engagement represents a key investment in which stakeholders mutually agree to share knowledge, benefits, and risk of failure. Effective stakeholder engagement prevents misconceptions. As HIV cure research advances from early trials involving subjects with generally favorable prognosis to studies involving greater risk and uncertainty, success may depend on early and deliberate engagement of stakeholders. PMID:26061668

Stakeholder Engagement in HIV Cure Research: Lessons Learned from Other HIV Interventions and the Way Forward.

PubMed

Lo, Ying-Ru; Chu, Carissa; Ananworanich, Jintanat; Excler, Jean-Louis; Tucker, Joseph D

2015-07-01

Clinical and basic science advances have raised considerable hope for achieving an HIV cure by accelerating research. This research is dominated primarily by issues about the nature and design of current and future clinical trials. Stakeholder engagement for HIV cure remains in its early stages. Our analysis examines timing and mechanisms of historical stakeholder engagement in other HIV research areas for HIV-uninfected individuals [vaccine development and pre-exposure prophylaxis (PrEP)], and HIV-infected individuals (treatment as prevention, prevention of mother-to-child transmission, and treatment of acute HIV infection) and articulate a plan for HIV cure stakeholder engagement. The experience from HIV vaccine development shows that early engagement of stakeholders helped manage expectations, mitigating the failure of several vaccine trials, while paving the way for subsequent trials. The relatively late engagement of HIV stakeholders in PrEP research may partly explain some of the implementation challenges. The treatment-related stakeholder engagement was strong and community-led from the onset and helped translation from research to implementation. We outline five steps to initiate and sustain stakeholder engagement in HIV cure research and conclude that stakeholder engagement represents a key investment in which stakeholders mutually agree to share knowledge, benefits, and risk of failure. Effective stakeholder engagement prevents misconceptions. As HIV cure research advances from early trials involving subjects with generally favorable prognosis to studies involving greater risk and uncertainty, success may depend on early and deliberate engagement of stakeholders.

The effect of ultra-violet light curing on the molecular structure and fracture properties of an ultra low-k material

NASA Astrophysics Data System (ADS)

Smith, Ryan Scott

As the gate density increases in microelectronic devices, the interconnect delay or RC response also increases and has become the limiting delay to faster devices. In order to decrease the RC time delay, a new metallization scheme has been chosen by the semiconductor industry. Copper has replaced aluminum as the metal lines and new low-k dielectric materials are being developed to replace silicon dioxide. A promising low-k material is porous organosilicate glass or p-OSG. The p-OSG film is a hybrid material where the silicon dioxide backbone is terminated with methyl or hydrogen, reducing the dielectric constant and creating mechanically weak films that are prone to fracture. A few methods of improving the mechanical properties of p-OSG films have been attempted-- exposing the film to hydrogen plasma, electron beam curing, and ultra-violet light curing. Hydrogen plasma and electron-beam curing suffer from a lack of specificity and can cause charging damage to the gates. Therefore, ultra-violet light curing (UV curing) is preferable. The effect of UV curing on an ultra-low-k, k~2.5, p-OSG film is studied in this dissertation. Changes in the molecular structure were measured with Fourier Transform Infrared Spectroscopy and X-ray Photoelectron Spectroscopy. The evolution of the molecular structure with UV curing was correlated with material and fracture properties. The material properties were film shrinkage, densification, and an increase in dielectric constant. From the changes in molecular structure and material properties, a set of condensation reactions with UV light are predicted. The connectivity of the film increases with the condensation reactions and, therefore, the fracture toughness should also increase. The effect of UV curing on the critical and sub-critical fracture toughness was also studied. The critical fracture toughness was measured at four different mode-mixes-- zero, 15°, 32°, and 42°. It was found that the critical fracture toughness increases with UV exposure for all mode mixes. The sub-critical fracture toughness was measured in Mode I and found to be insensitive to UV cure. A simple reaction rate model is used to explain the difference in critical and sub-critical fracture toughness.

Glatiramer Injection

MedlinePlus

... symptoms flare up from time to time) of multiple sclerosis (MS; a disease in which the nerves do ... minutes, but do not rub it. Glatiramer controls multiple sclerosis but does not cure it. Continue to use ...

Viscoelastic properties of addition-cured polyimides used in high temperature polymer matrix composites

NASA Technical Reports Server (NTRS)

Roberts, Gary D.; Malarik, Diane C.; Robaidek, Jerrold O.

1991-01-01

The viscoelastic properties of an addition-cured polyimide, PMR-15, were evaluated through dynamic mechanical and stress relaxation testing. Below the glass transition temperature, the dynamic mechanical properties of the composites are strongly affected by the absorbed moisture in the resin. At temperature 20 C and more above the glass transition temperature, the storage modulus increases continuously with time, indicating that additional crosslinking is occurring in the resin. For resin moisture contents less than 2 percent, stress relaxation curves measured at different temperatures can be superimposed using horizontal shifts along the log(time) axis with only small shifts along the vertical axis.

Effects of Using Pozzolan and Portland Cement in the Treatment of Dispersive Clay

PubMed Central

Vakili, A. H.; Selamat, M. R.; Moayedi, H.

2013-01-01

Use of dispersive clay as construction material requires treatment such as by chemical addition. Treatments to dispersive clay using pozzolan and Portland cement, singly and simultaneously, were carried out in this study. When used alone, the optimum amount of pozzolan required to treat a fully dispersive clay sample was 5%, but the curing time to reduce dispersion potential, from 100% to 30% or less, was 3 month long. On the other hand, also when used alone, a 3% cement content was capable of reducing dispersion potential to almost zero percent in only 7 days; and a 2% cement content was capable of achieving similar result in 14 days. However, treatment by cement alone is costly and could jeopardize the long term performance. Thus, a combined 5% pozzolan and 1.5% cement content was found capable of reducing dispersion potential from 100% to zero percent in 14 days. The results indicate that although simultaneous treatment with pozzolan and cement would extend the required curing time in comparison to treatment by cement alone of a higher content, the task could still be carried out in a reasonable period of curing time while avoiding the drawbacks of using either pozzolan or cement alone. PMID:23864828

Characterization of free volume during vulcanization of styrene butadiene rubber by means of positron annihilation lifetime spectroscopy and dynamic mechanical test.

PubMed

Marzocca, A J; Cerveny, S; Salgueiro, W; Somoza, A; Gonzalez, L

2002-02-01

An experimental investigation was performed to study the effect on the free volume of the advance of the cross-linking reaction in a copolymer of styrene butadiene rubber by sulfur vulcanization. The dynamic modulus and loss tangent were evaluated over samples cured for different times at 433 K by dynamic mechanical tests over a range of frequencies between 5 and 80 Hz at temperatures between 200 and 300 K. Using the William-Landel-Ferry relationship, master curves were obtained at a reference temperature of 298 K and the coefficients c(0)(1) and c(0)(2) were evaluated. From these parameters the dependence of the free volume on the cure time is obtained. Positron annihilation lifetime spectroscopy was also used to estimate the size and number density of free volume sites in the material. The spectra were analyzed in terms of continuous distributions of free volume size. The results suggest an increase of the lower free volume size when cross linking takes place. Both techniques give similar results for the dependence of free volume on the time of cure of the polymer.

Nondestructive observation of teeth post core-space using optical coherence tomography: comparison with microcomputed tomography and live images

NASA Astrophysics Data System (ADS)

Minamino, Takuya; Mine, Atsushi; Matsumoto, Mariko; Sugawa, Yoshihiko; Kabetani, Tomoshige; Higashi, Mami; Kawaguchi, Asuka; Ohmi, Masato; Awazu, Kunio; Yatani, Hirofumi

2015-10-01

No previous reports have observed inside the root canal using both optical coherence tomography (OCT) and x-ray microcomputed tomography (μCT) for the same sample. The purpose of this study was to clarify both OCT and μCT image properties from observations of the same root canal after resin core build-up treatment. As OCT allows real-time observation of samples, gap formation may be able to be shown in real time. A dual-cure, one-step, self-etch adhesive system bonding agent, and dual-cure resin composite core material were used in root canals in accordance with instructions from the manufacturer. The resulting OCT images were superior for identifying gap formation at the interface, while μCT images were better to grasp the tooth form. Continuous tomographic images from real-time OCT observation allowed successful construction of a video of the resin core build-up procedure. After 10 to 12 s of light curing, a gap with a clear new signal occurred at the root-core material interface, proceeding from the coronal side (6 mm from the cemento-enamel junction) to the apical side of the root.

Effects of using pozzolan and Portland cement in the treatment of dispersive clay.

PubMed

Vakili, A H; Selamat, M R; Moayedi, H

2013-01-01

Use of dispersive clay as construction material requires treatment such as by chemical addition. Treatments to dispersive clay using pozzolan and Portland cement, singly and simultaneously, were carried out in this study. When used alone, the optimum amount of pozzolan required to treat a fully dispersive clay sample was 5%, but the curing time to reduce dispersion potential, from 100% to 30% or less, was 3 month long. On the other hand, also when used alone, a 3% cement content was capable of reducing dispersion potential to almost zero percent in only 7 days; and a 2% cement content was capable of achieving similar result in 14 days. However, treatment by cement alone is costly and could jeopardize the long term performance. Thus, a combined 5% pozzolan and 1.5% cement content was found capable of reducing dispersion potential from 100% to zero percent in 14 days. The results indicate that although simultaneous treatment with pozzolan and cement would extend the required curing time in comparison to treatment by cement alone of a higher content, the task could still be carried out in a reasonable period of curing time while avoiding the drawbacks of using either pozzolan or cement alone.

Pharmacodynamic study on insomnia-curing effects of Shuangxia Decoction in Drosophila melanogaster.

PubMed

Zhang, Zhi-Qian; Degejin; Geng, Di; Zhang, Qi; Tian, Yan; Xi, Yuan; Wang, Wen-Qi; Tang, Hua-Qi; Xu, Bing; Lin, Hong-Ying; Sun, Yi-Kun

2016-09-01

The present study aimed to establish a pharmacodynamic method using the pySolo software to explore the influence of freeze-dried powders of Shuangxia Decoction (SXD) on the sleep of normal Drosophila melanogaster and the Drosophila melanogaster whose sleep was divested by light. The dose-effect and the time-effect relationships of SXD on sleep were examined. The effect-onset concentration of SXD was 0.25%, the plateau appeared at the concentration of 2.5% and the total sleep time showed a downtrend when the concentration was greater than 2.5%. The sleep time was the longest on the fourth day after SXD was given. The fruit fly sleep deprivation model was repeated by light stimulation at night. The middle dosage group (2.5%) had the best insomnia-curing effect. In conclusion, using the pySolo software, an approach for the pharmacodynamics study was established with Drosophila melanogaster as a model organism to determine the insomnia-curing effects of the traditional Chinese medicine (TCM). Our results demonstrated the reliability of this method. The freeze-dried powders of SXD could effectively improve the sleep quality of Drosophila melanogaster. Copyright © 2016 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.