Viscosity Method for Hierarchical Fixed Point Problems with an Infinite Family of Nonexpansive Nonself-Mappings

A viscosity method for hierarchical fixed point problems is presented to solve variational inequalities, where the involved mappings are nonexpansive nonself-mappings. Solutions are sought in the set of the common fixed points of an infinite family of nonexpansive nonself-mappings. The results generalize and improve the recent results announced by many other authors

Estimation of accelerated failure time models with random effects

Correlated survival data with possible censoring are frequently encountered in survival analysis. This includes multi center studies where subjects are clustered by clinical or other environmental factors that influence expected survival time, studies where times to several different events are monitored on each subject, and studies using groups of genetically related subjects. To analyze such data, we propose accelerated failure time (AFT) models based on lognormal frailties. AFT models provide a linear relationship between the log of the failure time and covariates that affect the expected time to failure by contracting or expanding the time scale. These models account for within cluster association by incorporating random effects with dependence structures that may be functions of unknown covariance parameters. They can be applied to right, left or interval-censored survival data. To estimate model parameters, we consider an approximate maximum likelihood estimation procedure derived from the Laplace approximation. This avoids the use of computationally intensive methods needed to evaluate the exact log-likelihood, such as MCMC methods or numerical integration that are not feasible for large data sets. Asymptotic properties of the proposed estimators are established and small sample performance is evaluated through several simulation studies. The fixed effects parameters are estimated well with little absolute bias. Asymptotic formulas tend to underestimate the standard errors for small cluster sizes. Reliable estimates depend on both the number of clusters and cluster size. The methodology is used to analyze data taken from the Minnesota Breast Cancer Family Resource to examine age-at-onset of breast cancer for women in 426 families

Modeling Based on Elman Wavelet Neural Network for Class-D Power Amplifiers

In Class-D Power Amplifiers (CDPAs), the power supply noise can intermodulate with the input signal, manifesting into power-supply induced intermodulation distortion (PS-IMD) and due to the memory effects of the system, there exist asymmetries in the PS-IMDs. In this paper, a new behavioral modeling based on the Elman Wavelet Neural Network (EWNN) is proposed to study the nonlinear distortion of the CDPAs. In EWNN model, the Morlet wavelet functions are employed as the activation function and there is a normalized operation in the hidden layer, the modification of the scale factor and translation factor in the wavelet functions are ignored to avoid the fluctuations of the error curves. When there are 30 neurons in the hidden layer, to achieve the same square sum error (SSE) $\epsilon_{min}=10^{-3}$, EWNN needs 31 iteration steps, while the basic Elman neural network (BENN) model needs 86 steps. The Volterra-Laguerre model has 605 parameters to be estimated but still can't achieve the same magnitude accuracy of EWNN. Simulation results show that the proposed approach of EWNN model has fewer parameters and higher accuracy than the Volterra-Laguerre model and its convergence rate is much faster than the BENN model

Sustainable plant-based ingredients as wheat flour substitutes in bread making

Bread as a staple food has been predominantly prepared from refined wheat flour. The world’s demand for food is rising with increased bread consumption in developing countries where climate conditions are unsuitable for wheat cultivation. This reliance on wheat increases the vulnerability to wheat supply shocks caused by force majeure or man-made events, in addition to negative environmental and health consequences. In this review, we discuss the contribution to the sustainability of food systems by partially replacing wheat flour with various types of plant ingredients in bread making, also known as composite bread. The sustainable sources of non-wheat flours, their example use in bread making and potential health and nutritional benefits are summarized. Non-wheat flours pose techno-functional challenges due to significantly different properties of their proteins compared to wheat gluten, and they often contain off-favor compounds that altogether limit the consumer acceptability of final bread products. Therefore, we detail recent advances in processing strategies to improve the sensory and nutritional profiles of composite bread. A special focus is laid on fermentation, for its accessibility and versatility to apply to different ingredients and scenarios. Finally, we outline research needs that require the synergism between sustainability science, human nutrition, microbiomics and food science.Peer reviewe

Investigation of CO2 storage capacity in open saline aquifers with numerical models

AbstractAccurate calculation of carbon dioxide (CO2) storage capacity in deep saline aquifers is a challenging task. However an assessment must be performed to determine whether there is sufficient capacity in a storage site for any CO2 sequestration project. We evaluated the CO2 storage capacity for a simplified reservoir system, which the layered potential storage formations are overlaid by sealing cap rock. This study aims at determining CO2 storage capacity for the injection of CO2 in opened saline formations using numerical simulation method. In this study, a 3D numerical model was developed for the investigation. Detailed processes for the storage capacity estimation are derived. The impact of injection strategy and the residual gas saturation on storage capacity was investigated. It is shown that both of the injection strategy and the residual gas saturation have a great impact on the spatial distribution of CO2 plume and the effective storage of CO2 in the reservoir. Simulation results also indicate that the injection well distribution may significantly influence the use of the formation porous space for CO2 storage. From this study, we may conclude that the most accurate way to estimate storage capacity is through construction of a basin scale three-dimensional numerical model for specific storage site by incorporating detailed geological information of the site and injection scheme used

Exploring the functionality of in situ produced dextran in high-protein or wholegrain enriched wheat bread

Utilization of grain legumes (such as faba bean) and minor cereals (such as sorghum and millet) is constantly growing since consumers are increasingly interested in sustainable, plant based and health promoting foods. Grain legumes and minor cereals are raw materials with high nutritional quality due to high content of protein, dietary fibre and other bioactive compounds. Utilization of these grains is challenging as they have negative impact on product texture and flavour. Sourdough technology is one of the “clean label” options to improve technological functionality of these grains. The aim of this thesis was to study the influence of faba bean, sorghum and millet on technological and nutritional properties of composite wheat bread. Wheat flour was replaced with faba bean (30%), sorghum or millet flours (50%), which were either native or fermented. Utilization of native flours had detrimental effect on the rheological properties of dough as well as the volume, texture and sensory properties of bread in comparison to 100% wheat control breads. In contrast, mildly acidified and dextran-containing flours improved all properties of composite breads. The functionality of sourdough was based on sufficient production of dextran and mild acidification. Faba bean sourdough fermented with Weissella confusa VTT E-143403 (dextran content of 5.2% dry weight) improved the specific volume (21%) and texture of breads, especially softness (12%). However, faba bean sourdough fermented with Leuconostoc pseudomesenteroides DSM 20193 (dextran content of 3.6% d.w.) decreased bread volume and increased crumb hardness, probably due to the higher acidification. Furthermore, efficacy to improve shelf-life (delay staling rate) was shown to be linked to slower starch retrogradation and improved water retention. Sourdough fermentation also increased the level of free phenolic compounds in millet and sorghum. Fermentation of millet decreased starch in vitro digestibility (lower predicted glycemic index), while improving the in vitro digestibility of proteins. These changes may be attributed to the production of organic acids and concomitant activation of hydrolytic enzymes like glycoside hydrolase, cellulases, esterases and proteases. Utilization of tailored sourdough technology had a significant impact on the sensory properties of sorghum breads. Sourdough fermentation of sorghum without dextran increased unpleasant flavour properties such as acidic, bitter flavour and aftertaste, probably due to increased content of acids and small molecular weight polyphenols (e.g. caffeic acid). This study showed that dextran containing sorghum breads had less intensive acidic and bitter flavour and milder aftertaste even though the actual acidity and polyphenol compositions was the same as in control breads. This revealed the exceptional ability of dextran to mask acidic and bitter flavour notes. This observation was further verified by adding purified dextran (0.12−0.96% bread weight) to white wheat bread together with acid and bitter flavour compounds (lactic/acetic acid and caffeine). When the amount of dextran was sufficient (> 0.43% b.w.), the perceived intensity of acidic and bitter flavours in the bread decreased. This thesis demonstrated efficient production of dextran in situ in faba bean, sorghum and millet flours during sourdough fermentation, which facilitates production of nutritionally high quality composite breads without additives. Additionally, this thesis revealed for the first time the ability of dextran to modify sensation of acidic and bitter flavours, which allows future product innovations in plant based foods.Palkokasvien (kuten härkäpapu) ja eräiden viljojen (kuten durra ja hirssi) käyttö lisääntyy jatkuvasti, koska kuluttajia kiinnostavat yhä enemmän kestävästi tuotetut, kasvipohjaiset ja terveelliset elintarvikkeet. Vilja- ja palkokasvit sisältävät runsaasti proteiineja, ravintokuituja, polyfenoleja ja muita bioaktiivisia yhdisteitä, minkä ansiosta niiden ravitsemuksellinen laatu on hyvä. Palkokasveista, durrasta ja hirssistä tehtyjen jauhojen käyttäminen on kuitenkin haastavaa, sillä ne vaikuttavat usein negatiivisesti tuotteen aistinvaraisiin ominaisuuksiin, kuten rakenteeseen ja makuun. Hapanjuurikäyminen eli raskitus on lisäaineeton keino muokata näiden raaka-aineiden käyttökelpoisuutta esimerkiksi leivonnassa. Tässä työssä tutkittiin raskitettua härkäpapua, hirssiä tai durraa sisältävien leipien reologisia, teknologisia, ravitsemuksellisia sekä aistinvaraisia ominaisuuksia. Valkoisesta vehnäjauhosta oli korvattu osa joko härkäpapu- (30%), hirssi- (50%) tai durrajauholla (50%), jotka olivat joko käsittelemättömiä tai hapatettu maitohappobakteereilla. Käsittelemättömien jauhojen käyttö leivonnassa huononsi taikinan reologisia ominaisuuksia ja leivän ominaistilavuutta, rakennetta ja makua. Miedosti hapatetut, dekstraania sisältävät raskit paransivat kaikkia leivän ominaisuuksia. Raskin teknologinen funktionaalisuus perustui in situ tuotetun dekstraanin riittävään pitoisuuteen sekä raskileivän mietoon happamuustasoon. Weissella confusa VTT E-143403 kannalla raskitetun härkäpavun käyttö (dekstraania 5.2% kuivapainosta) paransi merkittävästi leivän tilavuutta ja rakennetta. Leuconostoc pseudomesenteroides DSM 20193 kannalla raskitettu jauho (3.6% dekstraania) pienensi leivän ominaistilavuutta, sekä lisäsi leivän rakenteen kovuutta, todennäköisesti johtuen merkittävästi suuremmasta happamuudesta. Fermentoidun raskin kyky pidentää leivän säilyvyyttä osoitettiin liittyvän hidastuneeseen tärkkelyksen uudelleen kiteytymiseen ja parantuneeseen vedensidontaan. Raskitus lisäsi durran ja hirssin vapaiden fenolien pitoisuutta. Hirssin raskitus vähensi tärkkelyksen sulavuutta in vitro (alentunut ennustettu glykeeminen indeksi). Hirssileivän proteiinin sulavuus in vitro sitä vastoin parani merkitsevästi raskituksen seurauksena. Nämä muutokset johtuivat todennäköisesti orgaanisten happojen muodostumisesta sekä tiettyjen hydrolyyttisten entsyymien, kuten glykosidihydrolaasin, sellulaasien, esteraasien ja proteaasien aktivoitumisesta. Raskituksella oli myös merkittävä vaikutus durraa sisältävän leivän aistittaviin ominaisuuksiin. Durran perinteinen raskitus ilman dekstraania lisäsi merkitsevästi epämiellyttävinä koettuja happamuutta, karvautta ja jälkimakua, todennäköisesti lisääntyneiden orgaanisten happojen ja pienimolekyylisten polyfenolien vapautumisen johdosta (voimakas karvas maku). Tämä tutkimus osoitti, että dekstraania sisältävässä durraleivässä nämä epämiellyttävinä koetut maut aistittiin merkitsevästi vähemmän voimakkaina, huolimatta leipien samanlaisesta happo- ja polyfenolikoostumuksesta, mikä paljasti dekstraanin poikkeuksellisen kyvyn pienentää aistittua karvautta ja happamuutta. Vaikutus todennettiin lisäämällä puhdistettua dekstraania (0.12-0.96% leivän painosta) mallivehnäleipään, johon lisättiin happaman ja karvaan aistimuksen aikaansaavia happoja ja kofeiinia. Dekstraanin lisäys riittävänä pitoisuutena (> 0.43%) pienensi merkittäväsi happaman ja karvaan maun voimakkuutta. Tämä väitöskirja osoitti, että dekstraania voidaan tuottaa tehokkaasti härkäpapu-, durra- ja hirssijauhoissa raskituksen aikana, mikä mahdollistaa ravitsemuksellisesti korkeatasoisten leipien valmistuksen ilman lisäaineita. Tässä työssä osoitettiin myös ensimmäistä kertaa dekstraanin kyky muokata happaman ja karvaan maun aistimista, mikä mahdollistaa uudet tuoteinnovaatiot kasvipohjaisissa tuotteissa

Challenges and opportunities for wheat alternative grains in breadmaking : Ex-situ- versus in-situ-produced dextran

Background: The use of grains as an alternative to wheat in breadmaking has rapidly grown in the last few years, driven by the Sustainable Development Goals toward improving food security and promoting sustainable agriculture. Flours from legumes, pseudo-cereals, minor cereals and milling by-products, such as bran, are of particular interest. The production of partially substituted or wheat-free bread is, however, a challenging task in terms of texture and flavour attributes. Scope and approach: The present review covers recent advances in the application of dextrans in improving dough rheology, baking performance and bread flavour characteristics. Emphasis has been given to in situ application of dextran via sourdough technology as a & lsquo;clean label & rsquo; alternative to commercial hydrocolloid additives. Key findings and conclusions: In-situ dextran production leads to bread with higher specific volume, softer crumbs and increased moisture content. Dextran also provides an anti-staling effect attributable to its ability to reduce water mobility and retard starch retrogradation. A structure & ndash;function relationship has suggested that dextran with high molecular weight and less branching is superior in enhancing bread quality. Furthermore, mild acidification favours the functionality of dextran in dough and bread systems, while intensive acidification results in adverse effects. Lactic acid bacterial strains belonging to the genus Weissella exhibiting mild acidification are therefore appreciated in regard to the utilisation of in-situ produced dextran. This review highlights the novel application of dextran as a flavour masking agent to minimise off-flavours (e.g. beany flavour, bitter taste, and aftertaste) originating from non-wheat grains, consequently improving the acceptability of the final products.Peer reviewe