Formation and stability of lines produced by inkjet printing

To produce stable lines with parallel sides through inkjet printing, individual drops are deposited on a surface so that they coalesce; this initial liquid line (or bead) must remain stable until it forms a solid. The stable line width is shown to be bounded by two limits, with the lower bound (minimum line width) determined by the maximum drop spacing for stable coalescence and the upper bound determined by the minimum drop spacing below which a bulging instability occurs. The maximum stable track width is also a function of the velocity at which an inkjet printhead traverses the substrate. These bounds are presented in dimensionless form and are shown to agree well with experiment. To enable easier determination of the stability of an arbitrary ink/substrate combination, both the upper and lower bounds are presented in graphical forms to define a region of bead stability in an appropriate parameter space. © 2010 American Chemical Society

Review of a Large-Scale Pacific Rat Eradication Attempt from an Uninhabited World Heritage Site: Project Approach, Lessons Learnt, and Future Directions

The United Kingdom’s Overseas Territories support the vast majority of the globally threatened species for which the UK is responsible. Henderson Island (43 km²), located in the South Pacific and part of the Pitcairn Islands group, is a near-pristine example of a raised coralline atoll and is internationally recognized as a UNESCO World Heritage Site. Pacific (Polynesian) rats, introduced by Polynesian settlers about 700 years ago, have been implicated in the long-term decline towards extinction of the Henderson petrel, the loss of huge numbers of breeding seabirds from the island, and the extinction of endemic species. The eradication of Pacific rats is the only viable management option open to prevent the eventual extinction of the Henderson petrel and is a vital action in maintaining the Outstanding Universal Value of this World Heritage Site. The Royal Society for the Protection of Birds (RSPB), in partnership with the Government of the Pitcairn Islands, undertook a multi-year program of planning, fundraising, and partnership-building work which culminated in a GBP£1.5m (USD$2.4m) aerial bait dispersal operation in 2011. The work was carried out in August 2011 as part of an international “chain” of eradication operations (Palmyra Atoll, USA, and Enderbury and Birnie, Kiribati) carried out in succession. Seven months after completion of the operation, in March 2012, the first report of a rat sighting was received. This report was verified by a rapid response mission to the island in May 2012, followed by a further expedition to Henderson in November to assess the status of rat and bird populations. Concurrently, the RSPB began an evaluation process, commissioning 3 independent reviews of the entire operation in an effort to identify potential reasons for failure and maximize lessons learnt for the global eradication community. We conclude that a rigorous yet flexible planning process that engages both international expertise and local communities is essential. We make recommendations for consideration in the planning of future operations on Henderson and similar islands worldwide

Epigallocatechin-3-gallate (EGCG) consumption in the Ts65Dn model of Down syndrome fails to improve behavioral deficits and is detrimental to skeletal phenotypes

Down syndrome (DS) is caused by three copies of human chromosome 21 (Hsa21) and results in phenotypes including intellectual disability and skeletal deficits. Ts65Dn mice have three copies of ~ 50% of the genes homologous to Hsa21 and display phenotypes associated with DS, including cognitive deficits and skeletal abnormalities. DYRK1A is found in three copies in humans with Trisomy 21 and in Ts65Dn mice, and is involved in a number of critical pathways including neurological development and osteoclastogenesis. Epigallocatechin-3-gallate (EGCG), the main polyphenol in green tea, inhibits Dyrk1a activity. We have previously shown that EGCG treatment (~ 10 mg/kg/day) improves skeletal abnormalities in Ts65Dn mice, yet the same dose, as well as ~ 20 mg/kg/day did not rescue deficits in the Morris water maze spatial learning task (MWM), novel object recognition (NOR) or balance beam task (BB). In contrast, a recent study reported that an EGCG-containing supplement with a dose of 2–3 mg per day (~ 40–60 mg/kg/day) improved hippocampal-dependent task deficits in Ts65Dn mice. The current study investigated if an EGCG dosage similar to that study would yield similar improvements in either cognitive or skeletal deficits. Ts65Dn mice and euploid littermates were given EGCG [0.4 mg/mL] or a water control, with treatments yielding average daily intakes of ~ 50 mg/kg/day EGCG, and tested on the multivariate concentric square field (MCSF)—which assesses activity, exploratory behavior, risk assessment, risk taking, and shelter seeking—and NOR, BB, and MWM. EGCG treatment failed to improve cognitive deficits; EGCG also produced several detrimental effects on skeleton in both genotypes. In a refined HPLC-based assay, its first application in Ts65Dn mice, EGCG treatment significantly reduced kinase activity in femora but not in the cerebral cortex, cerebellum, or hippocampus. Counter to expectation, 9-week-old Ts65Dn mice exhibited a decrease in Dyrk1a protein levels in Western blot analysis in the cerebellum. The lack of beneficial therapeutic behavioral effects and potentially detrimental skeletal effects of EGCG found in Ts65Dn mice emphasize the importance of identifying dosages of EGCG that reliably improve DS phenotypes and linking those effects to actions of EGCG (or EGCG-containing supplements) in specific targets in brain and bone

Studying the creep behaviour of strechable capacitive sensor with barium titanate silicone elastomer composite

In this paper, the creep behaviour of stretchable interdigital capacitive (IDC) large strain sensors is studied. A generalized Kelvin-Voigt (GKV) model is used to study the creep behaviour of the sensor's substrate material, manufactured from silicone elastomer (Ecoflex 00−30) with barium titanate (BTO) filler. Creep experiments are performed on sensors with 10, 20, 30 and 40 wt% BTO nanoparticles with dimensions of 100 nm and 200 nm dispersed in the elastomer. The BTO was used to increase the overall permittivity of the substrate, hence raising the capacitance of the IDC sensor. The effect of BTO on the GKV model parameters was studied in detail through analysis of the creep response. The pristine Ecoflex silicone elastomer is predominately a hyperelastic material, which shows negligible creep, while the addition of BTO particles led to the composite exhibiting creep such that the composite behaves like a visco-hyperelastic material. Hence, this behaviour results in the creep affecting the electrical sensing performance of the capacitive strain sensors during static loading conditions. This information provides insights on the impact of composite composition on creep-resistance and output signal of the sensor (capacitance).</p

The effect of barium titanate ceramic loading on the stress relaxation behavior of barium titanate-silicone elastomer composites

The stress relaxation behavior of barium titanate (BTO)-elastomer (Ecoflex) composites, as used in large strain sensors, is studied using the generalized Maxwell-Wiechert model. In this article, we examine the stress relaxation behavior of ceramic polymer composites by conducting stress relaxation tests on samples prepared with varying the particle loading by 0, 10, 20, 30, and 40 wt% of 100 and 200 nm BTO ceramic particles embedded in a Ecoflex silicone-based hyperelastic elastomer. The influence of BTO on the Maxwell-Wiechert model parameters was studied through the stress relaxation results. While a pristine Ecoflex silicone elastomer is predominantly a hyperelastic material, the addition of BTO made the composite behave as a visco-hyperelastic material. However, this behavior was shown to have a negligible effect on the electrical sensing performance of the large strain sensor.</p

Studying the creep behaviour of strechable capacitive sensor with barium titanate silicone elastomer composite

In this paper, the creep behaviour of stretchable interdigital capacitive (IDC) large strain sensors is studied. A generalized Kelvin-Voigt (GKV) model is used to study the creep behaviour of the sensor's substrate material, manufactured from silicone elastomer (Ecoflex 00−30) with barium titanate (BTO) filler. Creep experiments are performed on sensors with 10, 20, 30 and 40 wt% BTO nanoparticles with dimensions of 100 nm and 200 nm dispersed in the elastomer. The BTO was used to increase the overall permittivity of the substrate, hence raising the capacitance of the IDC sensor. The effect of BTO on the GKV model parameters was studied in detail through analysis of the creep response. The pristine Ecoflex silicone elastomer is predominately a hyperelastic material, which shows negligible creep, while the addition of BTO particles led to the composite exhibiting creep such that the composite behaves like a visco-hyperelastic material. Hence, this behaviour results in the creep affecting the electrical sensing performance of the capacitive strain sensors during static loading conditions. This information provides insights on the impact of composite composition on creep-resistance and output signal of the sensor (capacitance).</p

Patient experiences through head and neck cancer: Information delivery combatting psychological distress

As part of a larger study investigating the utility of electronic decision support tools for patients with head and neck cancer (HNC), this article describes the patient experience of receiving cancer treatment in British Columbia, Canada. It aims to give voice to the patient experience and recommend a model of psychological adjustment for clinicians and clinical service management to consider to refine patient centric care pathways for HNC. Based in phenomenology, semi-structured interviews were conducted with 12 survivors of HNC, audio-video recorded, and thematically analyzed. Three themes were identified: (1) patients have high, though varying information needs; (2) an emotional experience; and (3) coping, strength, and resiliency. These themes arose from six concepts: (1) information needs; (2) fear of the unknown; (3) desire for personalized information; (4) varying degrees of information needs; (5) fear as a motivator versus stressor; and (6) high information needs on life after treatment. Conclusions: The patient experience must be considered through the full care trajectory and into survivorship to provide the right information to the correct patient at the optimal time. Patient journey mapping may be a novel approach to exploring the temporal relationship between information needs and the patient experience along the cancer continuum to uncover opportune moments, from the patient perspective, for knowledge and supportive care intervention. The model of psychological adjustment by Calver et al. (2019) can be considered to inform the delivery of cancer care information in a method recognizing the patient as the ultimate knowledge holder. Experience Framework This article is associated with the Patient, Family & Community Engagement lens of The Beryl Institute Experience Framework (https://www.theberylinstitute.org/ExperienceFramework). Access other PXJ articles related to this lens. Access other resources related to this lens

Sequencing conjugated polymers by eye.

The solid-state microstructure of a conjugated polymer is the most important parameter determining its properties and performance in (opto)-electronic devices. A huge amount of research has been dedicated to tuning and understanding how the sequence of monomers, the nature and frequency of defects, the exact backbone conformation, and the assembly and crystallinity of conjugated polymers affect their basic photophysics and charge transporting properties. However, because of the lack of reliable high-resolution analytical techniques, all the structure-property relations proposed in the literature are based either on molecular modeling or on indirect experimental data averaged on polydisperse samples. We show that a combination of electrospray vacuum deposition and high-resolution scanning tunneling microscopy allows the imaging of individual conjugated polymers with unprecedented detail, thereby unraveling structural and self-assembly characteristics that have so far been impossible to determine

Severe early onset preeclampsia: short and long term clinical, psychosocial and biochemical aspects

Preeclampsia is a pregnancy specific disorder commonly defined as de novo hypertension and proteinuria after 20 weeks gestational age. It occurs in approximately 3-5% of pregnancies and it is still a major cause of both foetal and maternal morbidity and mortality worldwide1. As extensive research has not yet elucidated the aetiology of preeclampsia, there are no rational preventive or therapeutic interventions available. The only rational treatment is delivery, which benefits the mother but is not in the interest of the foetus, if remote from term. Early onset preeclampsia (<32 weeks’ gestational age) occurs in less than 1% of pregnancies. It is, however often associated with maternal morbidity as the risk of progression to severe maternal disease is inversely related with gestational age at onset2. Resulting prematurity is therefore the main cause of neonatal mortality and morbidity in patients with severe preeclampsia3. Although the discussion is ongoing, perinatal survival is suggested to be increased in patients with preterm preeclampsia by expectant, non-interventional management. This temporising treatment option to lengthen pregnancy includes the use of antihypertensive medication to control hypertension, magnesium sulphate to prevent eclampsia and corticosteroids to enhance foetal lung maturity4. With optimal maternal haemodynamic status and reassuring foetal condition this results on average in an extension of 2 weeks. Prolongation of these pregnancies is a great challenge for clinicians to balance between potential maternal risks on one the eve hand and possible foetal benefits on the other. Clinical controversies regarding prolongation of preterm preeclamptic pregnancies still exist – also taking into account that preeclampsia is the leading cause of maternal mortality in the Netherlands5 - a debate which is even more pronounced in very preterm pregnancies with questionable foetal viability6-9. Do maternal risks of prolongation of these very early pregnancies outweigh the chances of neonatal survival? Counselling of women with very early onset preeclampsia not only comprises of knowledge of the outcome of those particular pregnancies, but also knowledge of outcomes of future pregnancies of these women is of major clinical importance. This thesis opens with a review of the literature on identifiable risk factors of preeclampsia