875 resultados para retention of fiber posts
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Retention of overdentures is important for patients' satisfaction. The study tested whether the clinical performance of retentive clips made of poly-ether-ether-ketone (PEEK) is superior to those made of poly-oxy-methylene (POM).
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OBJECTIVES The aim was to study the impact of the defect size of endodontically treated incisors compared to dental implants as abutments on the survival of zirconia two-unit anterior cantilever-fixed partial dentures (2U-FPDs) during 10-year simulation. MATERIALS AND METHODS Human maxillary central incisors were endodontically treated and divided into three groups (n = 24): I, access cavities rebuilt with composite core; II, teeth decoronated and restored with composite; and III as II supported by fiber posts. In group IV, implants with individual zirconia abutments were used. Specimens were restored with zirconia 2U-FPDs and exposed to two sequences of thermal cycling and mechanical loading. Statistics: Kaplan-Meier; log-rank tests. RESULTS During TCML in group I two tooth fractures and two debondings with chipping were found. Solely chippings occurred in groups II (2×), IV (2×), and III (1×). No significant different survival was found for the different abutments (p = 0.085) or FPDs (p = 0.526). Load capability differed significantly between groups I (176 N) and III (670 N), and III and IV (324 N) (p < 0.024). CONCLUSION Within the limitations of an in vitro study, it can be concluded that zirconia-framework 2U-FPDs on decoronated teeth with/without post showed comparable in vitro reliability as restorations on implants. The results indicated that restorations on teeth with only access cavity perform worse in survival and linear loading. CLINICAL RELEVANCE Even severe defects do not justify per se a replacement of this particular tooth by a dental implant from load capability point of view.
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Research examining programs designed to retain patients in health care focus on repeated interactions between outreach workers and patients (Bradford et al. 2007; Cheever 2007). The purpose of this study was to determine if patients who are peer-mentored at their intake exam remain in care longer and attend more physicians' visits than those who were not mentored. Using patients' medical records and a previously created mentor database, the study determined how many patients attended their intake visit but subsequently failed to establish regular care. The cohort study examined risk factors for establishing care, determined if patients lacking a peer mentor failed to establish care more than peer mentor assisted patients, and subsequently if peer mentored patients had better health outcomes. The sample consists of 1639 patients who were entered into the Thomas Street Patient Mentor Database between May 2005 and June 2007. The assignment to the mentored group was haphazardly conducted based on mentor availability. The data from the Mentor Database was then analyzed using descriptive statistical software (SPSS version 15; SPSS Inc., Chicago, Illinois, USA). Results indicated that patients who had a mentor at intake were more likely to return for primary care HIV visits at 90 and 180 days. Mentored patients also were more likely to be prescribed ART within 180 days from intake. Other risk factors that impacted remaining in care included gender, previous care status, time from diagnosis to intake visit, and intravenous drug use. Clinical health outcomes did not differ significantly between groups. This supports that mentoring did improve outcomes. Continuing to use peer-mentoring programs for HIV care may help in increasing retention of patients in care and improving patients' health in a cost effective manner. Future research on the effects of peer mentoring on mentors, and effects of concordance of mentor and patient demographics may help to further improve peer-mentoring programs. ^
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In prospective studies it is essential that the study sample accurately represents the target population for meaningful inferences to be drawn. Understanding why some individuals do not participate, or fail to continue to participate, in longitudinal studies can provide an empirical basis for the development of effective recruitment and retention strategies to improve response rates. This study examined the influence of social connectedness and self-esteem on long-term retention of participants, using secondary data from the “San Antonio Longitudinal Study of Aging” (SALSA), a population-based study of Mexican Americans (MAs) and European Americans (EAs) aged over 65 years residing in San Antonio, Texas. We tested the effect of social connectedness, self-esteem and socioeconomic status on participant retention in both ethnic groups. In MAs only, we analyzed whether acculturation and assimilation moderated these associations and/or had a direct effect on participant retention. ^ Low income, low frequency of social contacts and length of recruitment interval were significant predictors of non-completer status. Participants with low levels of social contacts were almost twice as likely as those with high levels of social contacts to be non-completers, even after adjustment for age, sex, ethnic group, education, household income, and recruitment interval (OR = 1.95, 95% CI: 1.26–3.01, p = 0.003). Recruitment interval consistently and strongly predicted non-completer status in all the models tested. Depending on the model, for each year beyond baseline there was a 25–33% greater likelihood of non-completion. The only significant interaction, or moderating, effect observed was between social contacts and cultural values among MAs. Specifically, MAs with both low social contacts and low acculturation on cultural values (i.e., placed high value on preserving Mexican cultural origins) were three and half times more likely to be non-completers compared with MAs in other subgroups comprised of the combination of these variables, even after adjustment for covariates. ^ Long term studies with older and minority participants are challenging for participant retention. Strategies can be designed to enhance retention by paying special attention to participants with low social contacts and, in MAs, participants with both low social contacts and low acculturation on cultural values. Minimizing the time interval between baseline and follow-up recruitment, and maintaining frequent contact with participants during this interval should also be is integral to the study design.^
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Existe una creciente necesidad de hacer el mejor uso del agua para regadío. Una alternativa eficiente consiste en la monitorización del contenido volumétrico de agua (θ), utilizando sensores de humedad. A pesar de existir una gran diversidad de sensores y tecnologías disponibles, actualmente ninguna de ellas permite obtener medidas distribuidas en perfiles verticales de un metro y en escalas laterales de 0.1-1,000 m. En este sentido, es necesario buscar tecnologías alternativas que sirvan de puente entre las medidas puntuales y las escalas intermedias. Esta tesis doctoral se basa en el uso de Fibra Óptica (FO) con sistema de medida de temperatura distribuida (DTS), una tecnología alternativa de reciente creación que ha levantado gran expectación en las últimas dos décadas. Específicamente utilizamos el método de fibra calentada, en inglés Actively Heated Fiber Optic (AHFO), en la cual los cables de Fibra Óptica se utilizan como sondas de calor mediante la aplicación de corriente eléctrica a través de la camisa de acero inoxidable, o de un conductor eléctrico simétricamente posicionado, envuelto, alrededor del haz de fibra óptica. El uso de fibra calentada se basa en la utilización de la teoría de los pulsos de calor, en inglés Heated Pulsed Theory (HPP), por la cual el conductor se aproxima a una fuente de calor lineal e infinitesimal que introduce calor en el suelo. Mediante el análisis del tiempo de ocurrencia y magnitud de la respuesta térmica ante un pulso de calor, es posible estimar algunas propiedades específicas del suelo, tales como el contenido de humedad, calor específico (C) y conductividad térmica. Estos parámetros pueden ser estimados utilizando un sensor de temperatura adyacente a la sonda de calor [método simple, en inglés single heated pulsed probes (SHPP)], ó a una distancia radial r [método doble, en inglés dual heated pulsed probes (DHPP)]. Esta tesis doctoral pretende probar la idoneidad de los sistemas de fibra óptica calentada para la aplicación de la teoría clásica de sondas calentadas. Para ello, se desarrollarán dos sistemas FO-DTS. El primero se sitúa en un campo agrícola de La Nava de Arévalo (Ávila, España), en el cual se aplica la teoría SHPP para estimar θ. El segundo sistema se desarrolla en laboratorio y emplea la teoría DHPP para medir tanto θ como C. La teoría SHPP puede ser implementada con fibra óptica calentada para obtener medidas distribuidas de θ, mediante la utilización de sistemas FO-DTS y el uso de curvas de calibración específicas para cada suelo. Sin embargo, la mayoría de aplicaciones AHFO se han desarrollado exclusivamente en laboratorio utilizando medios porosos homogéneos. En esta tesis se utiliza el programa Hydrus 2D/3D para definir tales curvas de calibración. El modelo propuesto es validado en un segmento de cable enterrado en una instalación de fibra óptica y es capaz de predecir la respuesta térmica del suelo en puntos concretos de la instalación una vez que las propiedades físicas y térmicas de éste son definidas. La exactitud de la metodología para predecir θ frente a medidas puntuales tomadas con sensores de humedad comerciales fue de 0.001 a 0.022 m3 m-3 La implementación de la teoría DHPP con AHFO para medir C y θ suponen una oportunidad sin precedentes para aplicaciones medioambientales. En esta tesis se emplean diferentes combinaciones de cables y fuentes emisoras de calor, que se colocan en paralelo y utilizan un rango variado de espaciamientos, todo ello en el laboratorio. La amplitud de la señal y el tiempo de llegada se han observado como funciones del calor específico del suelo. Medidas de C, utilizando esta metodología y ante un rango variado de contenidos de humedad, sugirieron la idoneidad del método, aunque también se observaron importantes errores en contenidos bajos de humedad de hasta un 22%. La mejora del método requerirá otros modelos más precisos que tengan en cuenta el diámetro del cable, así como la posible influencia térmica del mismo. ABSTRACT There is an increasing need to make the most efficient use of water for irrigation. A good approach to make irrigation as efficient as possible is to monitor soil water content (θ) using soil moisture sensors. Although, there is a broad range of different sensors and technologies, currently, none of them can practically and accurately provide vertical and lateral moisture profiles spanning 0-1 m depth and 0.1-1,000 m lateral scales. In this regard, further research to fulfill the intermediate scale and to bridge single-point measurement with the broaden scales is still needed. This dissertation is based on the use of Fiber Optics with Distributed Temperature Sensing (FO-DTS), a novel approach which has been receiving growing interest in the last two decades. Specifically, we employ the so called Actively Heated Fiber Optic (AHFO) method, in which FO cables are employed as heat probe conductors by applying electricity to the stainless steel armoring jacket or an added conductor symmetrically positioned (wrapped) about the FO cable. AHFO is based on the classic Heated Pulsed Theory (HPP) which usually employs a heat probe conductor that approximates to an infinite line heat source which injects heat into the soil. Observation of the timing and magnitude of the thermal response to the energy input provide enough information to derive certain specific soil thermal characteristics such as the soil heat capacity, soil thermal conductivity or soil water content. These parameters can be estimated by capturing the soil thermal response (using a thermal sensor) adjacent to the heat source (the heating and the thermal sources are mounted together in the so called single heated pulsed probe (SHPP)), or separated at a certain distance, r (dual heated pulsed method (DHPP) This dissertation aims to test the feasibility of heated fiber optics to implement the HPP theory. Specifically, we focus on measuring soil water content (θ) and soil heat capacity (C) by employing two types of FO-DTS systems. The first one is located in an agricultural field in La Nava de Arévalo (Ávila, Spain) and employ the SHPP theory to estimate θ. The second one is developed in the laboratory using the procedures described in the DHPP theory, and focuses on estimating both C and θ. The SHPP theory can be implemented with actively heated fiber optics (AHFO) to obtain distributed measurements of soil water content (θ) by using reported soil thermal responses in Distributed Temperature Sensing (DTS) and with a soil-specific calibration relationship. However, most reported AHFO applications have been calibrated under laboratory homogeneous soil conditions, while inexpensive efficient calibration procedures useful in heterogeneous soils are lacking. In this PhD thesis, we employ the Hydrus 2D/3D code to define these soil-specific calibration curves. The model is then validated at a selected FO transect of the DTS installation. The model was able to predict the soil thermal response at specific locations of the fiber optic cable once the surrounding soil hydraulic and thermal properties were known. Results using electromagnetic moisture sensors at the same specific locations demonstrate the feasibility of the model to detect θ within an accuracy of 0.001 to 0.022 m3 m-3. Implementation of the Dual Heated Pulsed Probe (DPHP) theory for measurement of volumetric heat capacity (C) and water content (θ) with Distributed Temperature Sensing (DTS) heated fiber optic (FO) systems presents an unprecedented opportunity for environmental monitoring. We test the method using different combinations of FO cables and heat sources at a range of spacings in a laboratory setting. The amplitude and phase-shift in the heat signal with distance was found to be a function of the soil volumetric heat capacity (referred, here, to as Cs). Estimations of Cs at a range of θ suggest feasibility via responsiveness to the changes in θ (we observed a linear relationship in all FO combinations), though observed bias with decreasing soil water contents (up to 22%) was also reported. Optimization will require further models to account for the finite radius and thermal influence of the FO cables, employed here as “needle probes”. Also, consideration of the range of soil conditions and cable spacing and jacket configurations, suggested here to be valuable subjects of further study and development.
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The effects of fiber inclusion, feed form, and energy concentration of the diet on the growth performance of pullets from hatching to 5 wk age were studied in 2 experiments. In Experiment 1, there was a control diet based on cereals and soybean meal, and 6 extra diets that included 2 or 4% of cereal straw, sugar beet pulp (SBP), or sunflower hulls (SFHs) at the expense (wt/wt) of the whole control diet. From hatching to 5 wk age fiber inclusion increased (P < 0.05) ADG and ADFI, and improved (P < 0.05) energy efficiency (EnE; kcal AMEn/g ADG), but body weight (BW) uniformity was not affected. Pullets fed SFH tended to have higher ADG than pullets fed SBP (P = 0.072) with pullets fed straw being intermediate. The feed conversion ratio (FCR) was better (P < 0.05) with 2% than with 4% fiber inclusion. In Experiment 2, 10 diets were arranged as a 2×5 factorial with 2 feed forms (mash vs. crumbles) and 5 levels of AMEn (2,850, 2,900, 2,950, 3,000, and 3,050 kcal/kg). Pullets fed crumbles were heavier and had better FCR than pullets fed mash (P < 0.001). An increase in the energy content of the crumble diets reduced ADFI and improved FCR linearly, but no effects were detected with the mash diets (P < 0.01 and P < 0.05 for the interactions). Feeding crumbles tended to improve BW uniformity at 5 wk age (P = 0.077) but no effects were detected with increases in energy concentration of the diet. In summary, the inclusion of moderate amounts of fiber in the diet improves pullet performance from hatching to 5 wk age. The response of pullets to increases in energy content of the diet depends on feed form with a decrease in feed intake when fed crumbles but no changes when fed mash. Feeding crumbles might be preferred to feeding mash in pullets from hatching to 5 wk age.
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The effects of fiber inclusion, feed form, and energy concentration of the diet on the growth performance of pullets from hatching to 5 wk age were studied in 2 experiments. In Experiment 1, there was a control diet based on cereals and soybean meal, and 6 extra diets that included 2 or 4% of cereal straw, sugar beet pulp (SBP), or sunflower hulls (SFHs) at the expense (wt/wt) of the whole control diet. From hatching to 5 wk age fiber inclusion increased (P < 0.05) ADG and ADFI, and improved (P < 0.05) energy efficiency (EnE; kcal AMEn/g ADG), but body weight (BW) uniformity was not affected. Pullets fed SFH tended to have higher ADG than pullets fed SBP (P = 0.072) with pullets fed straw being intermediate. The feed conversion ratio (FCR) was better (P < 0.05) with 2% than with 4% fiber inclusion. In Experiment 2, 10 diets were arranged as a 2×5 factorial with 2 feed forms (mash vs. crumbles) and 5 levels of AMEn (2,850, 2,900, 2,950, 3,000, and 3,050 kcal/kg). Pullets fed crumbles were heavier and had better FCR than pullets fed mash (P < 0.001). An increase in the energy content of the crumble diets reduced ADFI and improved FCR linearly, but no effects were detected with the mash diets (P < 0.01 and P < 0.05 for the interactions). Feeding crumbles tended to improve BW uniformity at 5 wk age (P = 0.077) but no effects were detected with increases in energy concentration of the diet. In summary, the inclusion of moderate amounts of fiber in the diet improves pullet performance from hatching to 5 wk age. The response of pullets to increases in energy content of the diet depends on feed form with a decrease in feed intake when fed crumbles but no changes when fed mash. Feeding crumbles might be preferred to feeding mash in pullets from hatching to 5 wk age.
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A high-fidelity virtual tool for the numerical simulation of low-velocity impact damage in unidirectional composite laminates is proposed. A continuum material model for the simulation of intraply damage phenomena is implemented in a numerical scheme as a user subroutine of the commercially available Abaqus finite element package. Delaminations are simulated using of cohesive surfaces. The use of structured meshes, aligned with fiber directions allows the physically-sound simulation of matrix cracks parallel to fiber directions, and their interaction with the development of delaminations. The implementation of element erosion criteria and the application of intraply and interlaminar friction allow for the simulation of fiber splits and their entanglement, which in turn results in permanent indentation in the impacted laminate. It is shown that this simulation strategy gives sound results for impact energies bellow and above the Barely Visible Impact Damage threshold, up to laminate perforation conditions
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Insulin-regulated aminopeptidase (IRAP), a transmembrane aminopeptidase, is dynamically retained within the endosomal compartment of fibroblasts. The characteristics of this dynamic retention are rapid internalization from the plasma membrane and slow recycling back to the cell surface. These specialized trafficking kinetics result in <15% of IRAP on the cell surface at steady state, compared with 35% of the transferrin receptor, another transmembrane protein that traffics between endosomes and the cell surface. Here we demonstrate that a 29-amino acid region of IRAP's cytoplasmic domain (residues 56–84) is necessary and sufficient to promote trafficking characteristic of IRAP. A di-leucine sequence and a cluster of acidic amino acids within this region are essential elements of the motif that slows IRAP recycling. Rapid internalization requires any two of three distinct motifs: M15,16, DED64–66, and LL76,77. The DED and LL sequences are part of the motif that regulates recycling, demonstrating that this motif is bifunctional. In this study we used horseradish peroxidase quenching of fluorescence to demonstrate that IRAP is dynamically retained within the transferrin receptor-containing general endosomal recycling compartment. Therefore, our data demonstrate that motifs similar to those that determine targeting among distinct membrane compartments can also regulate the rate of transport of proteins from endosomal compartments. We propose a model for dynamic retention in which IRAP is transported from the general endosomal recycling compartment in specialized, slowly budding recycling vesicles that are distinct from those that mediate rapid recycling back to the surface (e.g., transferrin receptor-containing transport vesicles). It is likely that the dynamic retention of IRAP is an example of a general mechanism for regulating the distribution of proteins between the surface and interior of cells.
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In the latter half of the twentieth century the workforce dynamic changed when the number of women entering the workforce increased by record amounts. In direct opposition to this change was the inability of organizations to meet the needs of employees with childcare concerns. Organizations and employees alike are best served when policies, procedures, and benefits are implemented to achieve a positive work/life balance. Companies that institute benefits that are supportive to families observe decreases in turnover and increased employee retention. Employees who are offered family friendly resources have been known to stay with companies even when offered a higher salary elsewhere. Demonstrating that retention of valued employees is linked to an organizations ability to offer support for family needs.
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The electrical resistivity of carbon fiber reinforced cement composites (CFRCCs) has been widely studied, because of their utility as multifunctional materials. The percolation phenomenon has also been reported and modeled when the electrical behavior of those materials had to be characterized. Amongst the multiple applications of multifunctional cement composites the ability of a CFRCC to act as a strain sensor is attractive. This paper provides experimental data relating self-sensing function and percolation threshold, and studying the effect of fiber aspect ratio on both phenomena. Higher fiber slenderness permitted percolation at lower carbon fiber addition, affected mechanical properties and improved strain-sensing sensitivity of CFRCC, which was also improved if percolation had not been achieved.
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This paper examines the challenges facing the EU regarding data retention, particularly in the aftermath of the judgment Digital Rights Ireland by the Court of Justice of the European Union (CJEU) of April 2014, which found the Data Retention Directive 2002/58 to be invalid. It first offers a brief historical account of the Data Retention Directive and then moves to a detailed assessment of what the judgment means for determining the lawfulness of data retention from the perspective of the EU Charter of Fundamental Rights: what is wrong with the Data Retention Directive and how would it need to be changed to comply with the right to respect for privacy? The paper also looks at the responses to the judgment from the European institutions and elsewhere, and presents a set of policy suggestions to the European institutions on the way forward. It is argued here that one of the main issues underlying the Digital Rights Ireland judgment has been the role of fundamental rights in the EU legal order, and in particular the extent to which the retention of metadata for law enforcement purposes is consistent with EU citizens’ right to respect for privacy and to data protection. The paper offers three main recommendations to EU policy-makers: first, to give priority to a full and independent evaluation of the value of the data retention directive; second, to assess the judgment’s implications for other large EU information systems and proposals that provide for the mass collection of metadata from innocent persons, in the EU; and third, to adopt without delay the proposal for Directive COM(2012)10 dealing with data protection in the fields of police and judicial cooperation in criminal matters.
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Limited availability of P in soils to crops may be due to deficiency and/or severe P retention. Earlier studies that drew on large soil profile databases have indicated that it is not (yet) feasible to present meaningful values for "plant-available" soil P, obtained according to comparable analytical methods, that may be linked to soil geographical databases derived from 1:5 million scale FAO Digital Soil Map of the World, such as the 5 x 5 arc-minute version of the ISRIC-WISE database. Therefore, an alternative solution for studying possible crop responses to fertilizer-P applied to soils, at a broad scale, was sought. The approach described in this report considers the inherent capacity of soils to retain phosphorus (P retention), in various forms. Main controlling factors of P retention processes, at the broad scale under consideration, are considered to be pH, soil mineralogy, and clay content. First, derived values for these properties were used to rate the inferred capacity for P retention of the component soil units of each map unit (or grid cell) using four classes (i.e., Low, Moderate, High, and Very High). Subsequently, the overall soil phosphorus retention potential was assessed for each mapping unit, taking into account the P-ratings and relative proportion of each component soil unit. Each P retention class has been assigned to a likely fertilizer P recovery fraction, derived from the literature, thereby permitting spatially more detailed, integrated model-based studies of environmental sustainability and agricultural production at the global and continental level (< 1:5 million). Nonetheless, uncertainties remain high; the present analysis provides an approximation of world soil phosphorus retention potential.
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Water-in-oil microemulsions (w/o ME) capable of undergoing a phase-transition to lamellar liquid crystals (LC) or bicontinuous ME upon aqueous dilution were formulated using Crodarnol EO, Crill 1 and Crillet 4, an alkanol or alkanediol as cosurfactant and water. The hypothesis that phase-transition of ME to LC may be induced by tears and serve to prolong precomeal retention was tested. The ocular irritation potential of components and formulations was assessed using a modified hen's egg chorioallantoic membrane test (HET-CAM) and the preocular retention of selected formulations was investigated in rabbit eye using gamma scintigraphy. Results showed that Crill 1, Crillet 4 and Crodamol EO were non-irritant. However, all other cosurfactants investigated were irritant and their irritation was dependent on their carbon chain length. A w/o ME formulated without cosurfactant showed a protective effect when a strong irritant (0.1 M NaOH) was used as the aqueous phase. Precorneal clearance studies revealed that the retention of colloidal and coarse dispersed systems was significantly greater than an aqueous solution with no significant difference between ME systems (containing 5% and 10% water) as well as o/w emulsion containing 85% water. Conversely, a LC system formulated without cosurfactant displayed a significantly greater retention compared to other formulations. (c) 2005 Elsevier B.V. All rights reserved.
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The purpose of this research was to investigate the retention of flavour volatiles encapsulated in water-insoluble systems during high temperature–short time extrusion process. A protein precipitation method was used to produce water-insoluble capsules encapsulating limonene, and the capsules were added to the extruder feed material (cornstarch). A twin-screw extruder was used to evaluate the effect of capsule level of addition (0–5%), barrel temperature (125–145 °C) and screw speed (145–175 r.p.m.) on extruder parameters (torque, die pressure, specific mechanical energy, residence time distribution) and extrudate properties [flavour retention, texture, colour, density, expansion, water absorption index, water solubility index (WSI)]. Capsule level had a significant effect on extrusion conditions, flavour retention and extrudate physical properties. Flavour retention increased with the increase in capsule level from 0% to 2.5%, reached a maximum value at capsule level of 2.5% and decreased when the capsule level increased from 2.5% to 5%. The die pressure, torque, expansion ratio, hardness and WSI exhibited the opposite effect with the presence of capsules.