Search

In this study we describe a simple method to fabricate microarrays of polystyrene microbeads (PS-μbeads) on Thermanox coverslip surfaces using laser induced forward transfer (LIFT). A triazene polymer layer which acts as a dynamic release layer and propels the closely packed microspheres on the receiving substrate was used for this approach. The deposited features were characterized by optical microscopy, scanning electron microscopy, atomic force microscopy, and Raman spectroscopy. Ultrasonication was used to test the adherence of the transferred beads. In addition, the laser ejection of the PS-μbead pixels was investigated by time resolved shadowgraphy. It was found that stable PS-μbeads micropatterns without any specific immobilization process could be realized by LIFT. These results highlight the increasing role of LIFT in the development of biomaterials, drug delivery, and tissue engineering. [ABSTRACT FROM AUTHOR]

An optimized laser-induced forward transfer (LIFT) technique has been used to fabricate tri-color organic light-emitting diode (OLED) pixels. At reduced pressures, and with a defined donor-receiver gap, patterned depositions of polyfluorene-based OLED pixels have been achieved. OLED pixel functionality has been demonstrated and compared with devices made using conventional deposition techniques. In addition, improved functionality has been obtained by coating the cathode with an electron-injecting layer, a process not possible using conventional OLED fabrication techniques. The OLED pixels fabricated by LIFT reach efficiencies on the range of conventionally fabricated devices and even surpass them in the case of blue pixels. [ABSTRACT FROM AUTHOR]

Background: Nutrition in the first 1000 days between pregnancy and 24 months of life is critical for child health, and exclusive breastfeeding is promoted as the infant's best source of nutrition in the first 6 months. Caffeine is a central nervous system stimulant occurring naturally in some foods and used to treat primary apnoea in premature babies. However high caffeine intake can be harmful, and caffeine is transmitted into breastmilk., Aim: To systematically review the evidence on the effects of maternal caffeine consumption during breastfeeding on the breastfed child., Method: A systematic search was conducted to October 2017 in MEDLINE, EMBASE, Web of Science, CINAHL, and Cochrane Library. The British Library catalogue, which covers doctoral theses, was searched and PRISMA guidelines followed. Two reviewers screened for experimental, cohort, or case-control studies and performed independent quality assessment using the Newcastle-Ottawa scale. The main reviewer performed data extraction, checked by the second reviewer., Results: Two cohort, two crossover studies, and one N-of-1 trial were included for narrative synthesis. One crossover and two cohort studies of small sample sizes directly investigated maternal caffeine consumption. No significant effects on 24-hour heart rate, 24-hour sleep time, or frequent night waking of the breastfed child were found. One study found a decreased rate of full breastfeeding at 6 months postpartum. Two studies indirectly investigated caffeine exposure. Maternal chocolate and coffee consumption was associated with increased infant colic, and severe to moderate exacerbation of infant atopic dermatitis. However, whether caffeine was the causal ingredient is questionable. The insufficient and inconsistent evidence available had quality issues impeding conclusions on the effects of maternal caffeine consumption on the breastfed child., Conclusion: Evidence for recommendations on caffeine intake for breastfeeding women is scant, of limited quality and inconclusive. Birth cohort studies investigating the potential positive and negative effects of various levels of maternal caffeine consumption on the breastfed child and breastfeeding mother could improve the knowledge base and allow evidence-based advice for breastfeeding mothers. Systematic review registration number: CRD42017078790.

Patterned deposition of polymer light-emitting diode (PLED) pixels is a challenge for electronic display applications. PLEDs have additional problems requiring solvent orthogonality of different materials in adjacent layers. We present the fabrication of a PLED pixel by the sequential deposition of two different layers with laser-induced forward transfer (LIFT), a "dry" deposition technique. This novel use of LIFT has been compared to "normal" LIFT, where all the layers are transferred in a single step, and a conventional PLED fabrication process. For the sequential LIFT, a 50-nm film of an alcohol-soluble polyfluorene (PFN) is transferred onto a receiver with a transparent anode, before an aluminum cathode is transferred on top. Both steps use a triazene polymer dynamic release layer and are performed in a medium vacuum (1 mbar) across a 15 μm gap. The rough morphologies of the single-layer PFN pixels and the PLED device characteristics have been investigated and compared to both bilayer Al/PFN pixels fabricated by normal LIFT and conventionally fabricated devices. The functionality of the sequential LIFT pixels (0.003 cd/A, up to 200 mA/cm(2), at 30-40 V) demonstrates the suitability of LIFT for sequential patterned printing of different thin-film layers.

Laser-induced forward transfer (LIFT) has been used to print 0.6 mm × 0.5 mm polymer light-emitting diode (PLED) pixels with poly[2-methoxy, 5-(2-ethylhexyloxy)-1,4-phenylene vinylene] (MEH-PPV) as the light-emitting polymer. The donor substrate used in the LIFT process is covered by a sacrificial triazene polymer (TP) release layer on top of which the aluminium cathode and functional MEH-PPV layers are deposited. To enhance electron injection into the MEH-PPV layer, a thin poly(ethylene oxide) (PEO) layer on the Al cathode or a blend of MEH-PPV and PEO was used. These donor substrates have been transferred onto both plain indium tin oxide (ITO) and bilayer ITO/PEDOT:PSS (poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) blend) receiver substrates to create the PLED pixels. For comparison, devices were fabricated in a conventional manner on ITO substrates coated with a PEDOT:PSS hole-transporting layer. Compared to multilayer devices without PEO, devices with ITO/PEDOT:PSS/MEH-PPV:PEO blend/Al architecture show a 100 fold increase of luminous efficiency (LE) reaching a maximum of 0.45 cd/A for the blend at a brightness of 400 cd/m(2). A similar increase is obtained for the polymer light-emitting diode (PLED) pixels deposited by the LIFT process, although the maximum luminous efficiency only reaches 0.05 cd/A for MEH-PPV:PEO blend, which we have attributed to the fact that LIFT transfer was carried out in an ambient atmosphere. For all devices, we confirm a strong increase in device performance and stability when using a PEDOT:PSS film on the ITO anode. For PLEDs produced by LIFT, we show that a 25 nm thick PEDOT:PSS layer on the ITO receiver substrate considerably reduces the laser fluence required for pixel transfer from 250 mJ/cm(2) without the layer to only 80 mJ/cm(2) with the layer.