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The human body is exposed to many xenobiotic, potentially harmful compounds. The intestinal immune system is crucial in protecting the human body from these substances. Moreover, many microorganisms, residing in the gastrointestinal tract, play an important role in modulating immune responses. Pre- and probiotics may have beneficial effects on the microbial composition and activity within the human gut, subsequently affecting the immune system. Prebiotics can exert their effects via different mechanisms, like selectively stimulating the growth of bacteria by providing substrates or via direct immune stimulation. Probiotics may have beneficial health effects via competition with pathogens for substrates and binding intestinal sites, bioconversions of for example sugars into fermentation products with inhibitory properties, production of growth substrates like vitamins for the host, direct antagonism of pathogens via antimicrobial peptide production, reduction of inflammation and stimulation of immune cells. This review focuses on the different mechanisms via which the pre- and probiotics exert their beneficial effects on the host, addressing their immunomodulatory properties in particular. © 2019 Wageningen Academic Publishers.

Planar Circularly Symmetric (PCS) Electromagnetic Band-Gap (EBG) substrates have been recently proposed to suppress the surface waves in printed technology [1] [2]. The major advantage of the PCS-EBGs with respect to structures based on vertical pins [3] [4] is the fabrication simplicity since the dielectric slabs do not need to be perforated. With respect to other planar type of EBG [5], an advantage is that the surface waves launched by a central source are reduced equally in all radial directions. The motivation of this contribution is to design and measure a prototype which demonstrates the suppression of surface waves by a PCS-EBG of a single antenna printed on a dielectric substrate. Thanks to the presence of the PCS-EBG around the antenna, we obtain an enhancement of the bandwidth, efficiency and directivity performances. The study will present some design considerations for the PCS-EBG itself, and then will proceed with the manufactured and measured antennas. The results explicitly show the advantages in terms of bandwidth and radiation pattern of the proposed EBG substrate. A bandwidth of 20% is achieved without significant surface wave losses.

In order to reduce the costs of thin-film silicon solar cell production, a manufacturing concept in which amorphous silicon (a-Si) solar cells are produced in a roll-to-roll manner on a temporary metal substrate (temporary-superstrate process) has been introduced in the Helianthos Project. Later in the process the device is transferred to a permanent plastic substrate on which cells are monolithically series connected, resulting in PV modules. In the Helianthos pilot line, modules with efficiencies above 7% are obtained on 1-foot-wide foil. On 30 × 30 cm2 modules, initial efficiencies of 5.7% have been reached, while 60 cm2 modules cut from the 35 cm wide foil have reached stabilized efficiencies of 5.8%. Lab modules with the deposition of a-Si in a batch process on roll-to-roll deposited SnO2, have reached stabilized efficiencies of 6.7%. In order to increase efficiency, amorphous/microcrystalline (a-Si/μc-Si) tandem solar cells have been implemented in the temporary-superstrate process to fabricate flexible, lightweight tandem modules with monolithic series integration. A first module with an aperture area efficiency of 8.6% has been presented earlier. At present, an initial aperture area efficiency of 9.4% has been reached on a 60 cm 2 module. © 2006 IEEE.

Inkjet printing is widely being researched as enabling technology for printed electronics; however, there are scarce publications concerning the reliability of inkjet-printed structures on different substrates. The reliability of such structures under high humidity and high temperature conditions is treated in this work. To do so, the adhesion and resistivity of printed structures on PET, Rogers, PI and FR-4 materials are studied before and after a moisture resistance test. The samples present average resistivity values in the range of 12-106 μω·cm and only one specimen of the Rogers sample fails the reliability test. The Rogers sample presents perfect adhesion characteristics, the adhesion can be improved for the rest of the samples, especially for the PI sample. The general performance of inkjet-printed structures on different substrate materials is good.

In this manuscript we present the first successful application of a spatial atomic-layer-deposition process to thin film solar cells. Zn(O,S) has been grown by spatial atomic layer deposition (S-ALD) at atmospheric pressure and applied as buffer layer in rigid and flexible CIGS cells by a lab-scale (15×15 cm2) S-ALD set-up. We achieved values of cell efficiency (16 %) higher than the reference cells on glass substrate. © 2017 IEEE. Newport

The industrialization of perovskite solar cells (PSC) require processes to efficiently deposit the constituent layers over large areas. In this work we optimized the use of slot die coating process for both sheet-to-sheet (S2S) and roll-to-roll (R2R) manufacturing. Particular focus have been put on the control of the uniformity of perovskite crystallization by tailoring the ink formulation and the drying process in order to avoid any efficiency losses over an area increase of 3 orders of magnitude (from 0.09 to 144 cm2). In this way we were able to fabricate 144 cm2 modules with 13.8% stabilized efficiency on aperture area on glass (14.5% on active area). At the same time, by developing the R2R slot die deposition process of the perovskite layer, we demonstrated 160 cm2 flexible module with 10.1 % stabilized efficiency on aperture area (11.0% on active area). In addition, fully R2R coated cells exhibit up to 16% efficiency. An outlook on how to upscale more stable perovskite cells (i.e. with pin structure) will be given. These results prove how to optimize the upscaling process towards large area manufacturing of perovskite solar modules on both rigid and flexible substrate. © 2018 IEEE.

In this paper we demonstrate the use of inkjet printing as a facile digital fabrication tool for the cost effective manufacture of UHF RFID transfer tattoo tags and Frequency Selective Surfaces on low-cost flexible and porous substrates. Electrical and morphological properties of conductive features obtained from a range of metal nanoparticle inks and low temperature sintering methods, such as argon plasma and photonic flash, are evaluated. Large scale potential is addressed. cop. 2013; Society for Imaging Science and Technology.

This paper discusses the design and analysis of planar circularly symmetric (PCS) electromagnetic band gap (EBG) structures for reducing the surface waves excited by printed antennas on dense dielectric substrates. The key advantage of the circularly symmetric geometries is that a surface wave generated by a source located at its center experiences the same band gap effect in all radial directions. To obtain simple design rules of the PCS-EBGs for the optimization of the bandwidth, an equivalence is established between 2-D-EBGs and PCS-EBGs. Integrated planar printed antennas with bandwidths up to 20% are designed, manufactured and tested.

Planar circularly symmetric (PCS) electromagnetic band-gap (EBG) substrates have recently been proposed to suppress surface waves (Llombart, N. et al., 2004). The application of PCS-EBG to reduce the surface waves excited by an antenna printed on a dielectric slab is discussed. The study starts from a reference microstrip-excited, slot-coupled dipole that presents a relatively large bandwidth (about 12%) and relatively low efficiency (about 40%-60%) due to surface wave losses. Some design considerations on how to enhance the performance of this antenna by surrounding it with a PCS-EBG are then presented. Finally the measured results are presented. These explicitly show the advantages of the proposed EBG substrate in terms of bandwidth and radiation pattern. A bandwidth of 20% is achieved without significant surface wave losses. The results also show radical improvements in the isolation between antennas printed on the same substrate

The synthesis of a polypyrrole film on a non-conducting substrate is studied. A thin film of conducting polypyrrole is deposited on a non-conducting substrate by dipping the substrate in a pyrrole solution and subsequently in an oxidising solution containing Fe(ClO4)3 and HClO4. The influence of the acid concentration on the Fe3+ equilibria is calculated. The results of these calculations are in agreement with UV/VIS and pH measurements. The calculations show that for HClO4 concentrations of 0.50 M and higher the influence on the Fe3+ equilibria is negligible.

Despite the great promise of printed flexible electronics from2D crystals, and especially graphene, few scalable applica-tions have been reported so far that can be termed roll-to-rollcompatible. Here we combine screen printed graphene withphotonic annealing to realize radio-frequency identificationdevices with a reading range of up to 4 meters. Most notablyour approach leads to fatigue resistant devices showing lessthan 1% deterioration of electrical properties after 1000 bend-ing cycles. The bending fatigue resistance demonstrated on avariety of technologically relevant plastic and paper sub-strates renders the material highly suitable for various print-able wearable devices, where repeatable dynamic bendingstress is expected during usage. All applied printing and post-processing methods are compatible with roll-to-roll manufac-turing and temperature sensitive flexible substrates providinga platform for the scalable manufacturing of mechanicallystable and environmentally friendly graphene printed electronics.

Filamentous growth of Aspergillus oryzae on solid cereal substrates involves secretion of substrate converting enzymes and a solid substrate specific polarised hyphal growth phenotype. To identify proteins produced under these specific conditions, the extracts of A. oryzae grown on wheat-based media were analysed using N-terminal sequence analysis. In a submerged wheat-based growth medium of A. oryzae, besides α-amylase, also an arabinosidase and xylanase were abundantly produced. In the extracts of A. oryzae grown on wheat-based solid substrate besides α-amylase and chitinase, two new proteins of 16 and 27 kDa were identified. These hypothetical proteins showed only close homologies to filamentous fungal proteins. © 2005 Elsevier B.V. All rights reserved.

Miniaturization of biosensors is envisaged by the development of biochips consisting of parallel microarray patterns of binding sites on rigid substrates, such as glass or silicon. Thin plastic substrates are promising flexible alternatives because of the possibility for large-area roll-to-roll manufacturing of disposable chips at lower costs. Mature optical lithography technology faces many challenges when used to pattern flexible foils as a result of the substrate instabilities, especially at higher temperatures. In this work, flexible biochips with gold electrode patterns were fabricated on thin polyethylene naphthalate (PEN) foils using photolithography. The gold electrode structures of the chips were manufactured by direct metal patterning and by lift-off processing. Both methodologies resulted in well-defined electrode patterns as concluded from optical microscopy and scanning electron microscopy (SEM) characterization and resistance measurements. The biochips were successfully employed for the electrical and optical detection of DNA molecules. The DNA detection was based on the immobilization of capture DNA between electrode gaps, hybridization with biotin-labeled target DNA, and enzymatic silver enhancement. © 2009 American Chemical Society.

This paper reports a study on the dynamics of foil-based functional component self-alignment onto patterned test substrates and its demonstration when integrating a flexible sensor onto a printed circuitry. We investigate the dependence of alignment time and final precision of stacking of mm- and cm-sized foil dies on a number of system parameters, such as amount of assembly medium dispensed on target positions, size and weight of assembling dies and their initial misalignment. Using water as a medium for direct self-alignment, mm- and cm-sized square-shaped pre-marked foil dies were aligned with accuracy down to 30 μm and smaller, which reflects a high precision relatively to their lateral dimensions on patterned marked carriers. High-speed camera stage and image recognition tools were used for analyzing rapid capillary-driven self-alignment processes of marked foil dies. It is shown that there is a definite range of initial misalignment values allowing dies to align with high accuracy and yield within the same time window, whereas both under smaller and larger initial offsets, i.e. with dies correspondingly too close or too far from their target positions, yield and alignment precision is significantly lower. The high-alignment accuracy of mm- to cm-sized functional foils was demonstrated by means of the integration of an interdigitated electrodes (IDE) capacitive sensor to a flexible polymeric substrate. Additionally, high-yield electrical interconnection was performed using anisotropic conductive adhesives (ACA). The latter opens the perspective of efficiently assembling interesting new systems such as separately manufactured sensors, paper batteries and RFIDs components through the direct capillary-driven self-alignment approach and ACA electrical interconnection.

Inkjet printed silver lines contract to widths below 20-μm during drying on an organic planarization coating. Aspect ratios previously unprecedented with single pass inkjet printing on isotropic homogeneous substrates are obtained. This effect is caused by the subsequent evaporation of solvents from the ink, which results in a continuous increase of its surface tension and thus controlled dewetting. cop. 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A low-noise X-band microstrip hybrid VCO has been designed and realised using a 2 × 50 μm GaN-on-SiC pseudo-morphic HEMT as the active device. The transistor has been manufactured by TIGER and features a gate-length of 0.15 μm, an fT of 22 GHz, a break-down voltage of 42 Volts and an Idss, close to 1 A/mm. The VCO has been assembled with standard SMD reflow and chip-on-board technology on Rogers 4003 substrate material. The circuit is biased at +15 Volts and 38 mA and has a measured tuning range from 8.1 to 10.6 GHz, an output power level of +19 dBm and an average phase-noise level of-114 dBc/Hz @ 1 MHz offset.

The aim of the ConText project is to develop a vest with integrated sensors and electronics for constant monitoring of muscle activity. The vest measures muscle activity in order to derive the psychological stress level of a person. The ConText project proposes to develop a sensor technology, which requires no direct contact with the body, and to achieve a high level of integration of the sensors and electronics into textile. The realisation of contactless EMG sensors, textile integration of the sensors and the creation of a textile substrate with conductive wiring for data transmission and power supply will be the important parts of the project. The prototype will be used for dissemination and application development. © 2007 IEEE.

A capacitive pressure sensor was realized by means of a post-processing step on a low temperature co-fired ceramics (LTCC) substrate. The new sensor fabrication technology allows for integration of the sensor with interface circuitry and possibly also wireless transmission circuits on LTCC substrates to realize a truly autonomous sensor unit. A special feature of this sensor technology is the flush surface. The article describes the design considerations, and compares experimental data to the theoretical design. Special point of attention is the long-term behaviour of the soldering joint. Various design variants have been evaluated considering reproducibility and creep behaviour.

The parameters of the chromate bath, like temperature, pH, and fluoride content, strongly affect the morphology and chemical composition of the chromate conversion coating and as a consequence have a large influence on its corrosion performance. In this paper, electrochemical impedance spectroscopy (EIS) was used in combination with other techniques to investigate the role played by the pH of the chromate bath on the properties of the chromate film formed on Alclad 2024 aluminium alloy. Scanning electron microscopy (SEM), atomic force microscopy (AFM) and spectroscopic ellipsometry (SE) have shown the formation of a thicker and less dense chromate layer when the pH of the chromate bath is changed from 2.4 to 1.2. The analysis of the EIS spectra have highlighted that this change in pH leads to the formation of more protective and more resistant chromate corrosion products (CCP) inside the defects of the chromate film. When a thin, dense and protective layer of CCP is formed in the defects, the corrosion behaviour of the chromate conversion coating improves for two main reason: (a) further attack of the defects is avoided or delayed; (b) the change in volume caused by the formation of the CCP is limited resulting in a low level of stress in the film, which as a consequence is not detached from the aluminium substrate.

The application of numerical techniques for the design of a low cost pressure sensor is described. The numerical techniques assist in addressing issues related to the thermo-mechanical performance of the sensor. This comprises the selection of the materials and dimensions used for the sensor itself and the substrate on which it is mounted. Moreover, simulations are applied to aid in the selection of suitable solder interconnect materials and dimensions. Where possible, the accuracy of the numerical predictions is assessed by comparing them to experiments on physical prototypes. The application of numerical simulations allowed for a reduction in the number of physical tests and thereby a reduction in design time and costs.