6,181 research outputs found

    CFD model of slot die coating for lithium-ion battery electrodes in 2D and 3D with load balanced dynamic mesh refinement enabled with a local-slip boundary condition in OpenFOAM

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    Slot die coating is a state-of-the-art process to manufacture lithium-ion battery electrodes with high accuracy and reproducibility, covering a wide range of process conditions and material systems. Common approaches to predict process windows are one-dimensional calculations with a limited expressiveness. A more detailed analysis can be performed using CFD simulations, which are often based on in-house code or closed-source software. In this study, a two-phase CFD model in two and three dimensions was created in OpenFOAM with the intent to provide a method for more detailed investigations of the slot die coating process with open access to source code and files. A custom boundary condition enables the proper description of the wetting behavior in the two-dimensional model. The combination of standard no-slip boundary conditions at the substrate boundary with the volume-of-fluid solution algorithm leads to a method-related air entrainment, which was prevented by allowing local slip at the dynamic wetting line at the upstream meniscus in the two-dimensional model. Additionally, a load-balancing dynamic refinement algorithm was implemented to minimize the computational effort and increase the ease of use of the simulation environment. The simulation was validated by comparing the simulated process limits to experimental observations, showing good agreement. As a result, this model enables detailed analyses regarding the influences of slot die geometries, material properties, and process parameters on the coating stability and wet-film profile

    The emerging role of FTY720 (Fingolimod) in cancer treatment

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    FTY720 (Fingolimod) is a clinically approved immunomodulating therapy for multiple sclerosis that sequesters T-cells to lymph nodes through functional antagonism of sphingosine-1-phosphate 1 receptor. FTY720 also demonstrates a proven efficacy in multiple in vitro and in vivo cancer models, suggesting a potential therapeutic role in cancer patients. A potential anticancer mechanism of FTY720 is through the inhibition of sphingosine kinase 1, a proto-oncogene with in vitro and clinical cancer association. In addition, FTY720's anticancer properties may be attributable to actions on several other molecular targets. This study focuses on reviewing the emerging evidence regarding the anticancer properties and molecular targets of FTY720. While the clinical transition of FTY720 is currently limited by its immune suppression effects, studies aiming at FTY720 delivery and release together with identifying its key synergetic combinations and relevant patient subsets may lead to its rapid introduction into the clinic

    The Determinants of Good Newborn Care Practices in the Rural Areas of Nepal.

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    Newborn morbidity and mortality remains high despite a remarkable decline in the infant mortality and under five mortality rates in Nepal over the last decade (1996-2006). Research shows that newborns’ health outcome is associated with maternal and other factors. This study was designed to understand the factors that have an impact on three good newborn care practices: safe cord cutting, early breastfeeding and delayed bathing. The study used the interview data of 815 married women aged 15-49 years who delivered a live baby between February 2008 and February 2009, collected for the baseline survey of the Community-Based Maternal and Newborn Health program implemented in the Sindhuli district of Nepal. The mean age of the sample women was 26 years. Two-thirds of them were from disadvantaged indigenous caste/ethnicity groups, about 70% were uneducated and the majority were poor. Safe cord cutting, early breastfeeding and delayed bathing practices were studied for 803, 810 and 812 women respectively and 70.7%, 46.7%, and 16.6% of the eligible samples demonstrated the practices respectively. The logistic regression method was used to examine the association of independent factors with the outcome variables. Social gradient was found to be associated with all three practices. Rich women were more likely to demonstrate good practices and bearing a child at the prime age (20-34 years) was likely to result in safe cord cutting. Disadvantaged indigenous and ‘other’ caste/ethnicity women demonstrated unsafe cord cutting practices and dalit caste/ethnicity women demonstrated poor bathing practices. Maternal knowledge also emerged as a strong predictor of early breastfeeding and delayed bathing practices. Antenatal care from a SBA determined good breastfeeding and advice from a FCHV determined good bathing practices. The results showed that the uptake of antenatal and delivery services from a skilled birth attendant is unacceptably low in rural Nepal, which is a challenge for meeting the millennium development goals. The study recommends programmes for improving economic status as a key to improving newborn care practices. As the vast majority of the deliveries are still assisted by traditional birth attendants; including them in maternal health programmes is crucial. Increasing women’s access to a skilled birth attendant and boosting the spirit of the FCHVs to increase their efficiency is also recommended. Future research on newborn health should focus on identifying other determinants of newborn care practices and survival. Qualitative studies to understand the cultural perspectives of newborn care practices are also recommended

    4D Printing at the Microscale

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    3D printing of adaptive and dynamic structures, also known as 4D printing, is one of the key challenges in contemporary materials science. The additional dimension refers to the ability of 3D printed structures to change their properties—for example, shape—over time in a controlled fashion as the result of external stimulation. Within the last years, significant efforts have been undertaken in the development of new responsive materials for printing at the macroscale. However, 4D printing at the microscale is still in its early stages. Thus, this progress report will focus on emerging materials for 4D printing at the microscale as well as their challenges and potential applications. Hydrogels and liquid crystalline and composite materials have been identified as the main classes of materials representing the state of the art of the growing field. For each type of material, the challenges and critical barriers in the material design and their performance in 4D microprinting are discussed. Importantly, further necessary strategies are proposed to overcome the limitations of the current approaches and move toward their application in fields such as biomedicine, microrobotics, or optics

    A petri nets based design of cognitive radios using distributed signal processing

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    AbstractReconfigurability for transceivers for wireless access networks like Bluetooth, WiMAX and W-LAN will become increasingly important. An appropriately flexible and reliable software architecture, allowing the concurrent processing of different controlling tasks for wireless terminals will hence be an important asset. Already during the 1980s reconfigurable receivers were developed for radio intelligence in the short wave range and the concept of software radio (SR) was born. A software defined radio (SDR) is a practical version of an SR: The received signals are sampled after a suitable band selection filter, usually in the base band or a low intermediate frequency band. The signal processing in both SR and SDR requires a considerable amount of concurrent processes. Since Petri nets (PNs) are both simple and strong tools for the description and the design of such concurrent processes, it is recommendable to deploy them for SDR. SDRs have paved the way towards cognitive radios (CRs), which are based on SDRs that additionally sense their environments, track changes, and react upon their findings. A CR is an autonomous unit in a communications environment that frequently exchanges information with the networks it is able to access as well as with other CRs. In this communication, the authors will introduce a realization concept for a CR which forms the basis of a hardware/firmware demonstrator developed by the authors. This demonstrator makes use of a digital signal processor (DSP) which forms the core of the design and flexibly programmable hardware accelerators based on field programmable gate arrays (FPGAs). The authors will describe the solution also in view of the recent developments of IEEE 802.2

    Biofunctionalization of Metal–Organic Framework Nanoparticles via Combined Nitroxide‐Mediated Polymerization and Nitroxide Exchange Reaction

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    Surface engineering of metal–organic framework nanoparticles (MOF NPs), and enabling their post-synthetic modulation that facilitates the formation of bio-interfaces has tremendous potential for diverse applications including therapeutics, imaging, biosensing, and drug-delivery systems. Despite the progress in MOF NPs synthesis, colloidal stability and homogeneous dispersity—a desirable property for biotechnological applications, stands as a critical obstacle and remains a challenging task. In this report, dynamic surfaces modification of MOF NPs with polyethylene glycol (PEG) polymer is described using grafting-from PEGylation by employing nitroxide-mediated polymerization (NMP) and inserting arginylglycylaspartic acid (RGD) peptides on the surface via a nitroxide exchange reaction (NER). The dynamic modification strategy enables tailoring PEG-grafted MOF NPs of the type UiO-66-NH2 with improved colloidal stability, and high dispersity, while the morphology and lattice crystallinity are strictly preserved. The interaction of PEG-grafted MOF NPs with human serum albumin (HSA) protein under physiological conditions is studied. The PEG-grafted colloidal MOF NPs adsorb less HSA protein than the uncoated ones. Therefore, the described approach increases the scope of bio-relevant applications of colloidal MOF NPs by reducing nonspecific interactions using NMP based PEGylation, while preserving the possibility to introduce targeting moieties via NER for specific interactions

    Radiative transfer and the energy equation in SPH simulations of star formation

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    We introduce and test a new and highly efficient method for treating the thermal and radiative effects influencing the energy equation in SPH simulations of star formation. The method uses the density, temperature and gravitational potential of each particle to estimate a mean optical depth, which then regulates the particle's heating and cooling. The method captures -- at minimal computational cost -- the effects of (i) the rotational and vibrational degrees of freedom of H2, H2 dissociation, H0 ionisation, (ii) opacity changes due to ice mantle melting, sublimation of dust, molecular lines, H-, bound-free and free-free processes and electron scattering; (iv) external irradiation; and (v) thermal inertia. The new algorithm reproduces the results of previous authors and/or known analytic solutions. The computational cost is comparable to a standard SPH simulation with a simple barotropic equation of state. The method is easy to implement, can be applied to both particle- and grid-based codes, and handles optical depths 0<tau<10^{11}.Comment: Submitted to A&A, recommended for publicatio
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