Electrohydrodynamic and Aerosol Jet Printing for the Copatterning of Polydimethylsiloxane and Graphene Platelet Inks

The performance of soft sensing and actuation devices is dependent on their design, the electro‐mechanical response of materials, and the ability to copattern structural and functional features. For film based soft structures, such as wearable sensors and artificial muscles, manufacturing challenges exist that prevent the translation of technology from laboratory to practical application. In this work, a hybrid manufacturing technique is presented that integrates electro‐hydrodynamic and aerosol jet deposition to print multilayer, multimaterial structures. The combined approach overcomes the respective rheological constraints of the individual processes, while presenting a pathway to higher resolution computer‐controlled patterning. Electro‐hydrodynamic deposition of a polydimethylsiloxane elastomer is demonstrated and characterized, before being combined with aerosol jet deposition of a graphene platelet ink to produce functional devices. A proof‐of‐concept, multilayer capacitive sensor is presented as a first demonstration of the manufacturing technology

Establishing comprehensive oral assessments for children with safeguarding concerns.

The dental profession is well placed to contribute important information in child protection cases but no previous research has been reported that assesses the volume or impact of this information. Comprehensive oral assessment clinics were introduced and established as an integral part of comprehensive medical assessments for children with welfare concerns in Greater Glasgow and Clyde. An assessment protocol and standardised paperwork for comprehensive oral assessments were developed to enhance information sharing and patient access to appropriate care. Two cases are presented and discussed to demonstrate the value of dental input

Rapid diagnostic tests for determining dengue serostatus: a systematic review and key informant interviews.

OBJECTIVES: Vaccination for dengue with the live attenuated tetravalent CYD-TDV vaccine (Dengvaxia®) is only recommended in individuals who have had prior dengue virus (DENV) infection. Rapid diagnostic tests (RDT) for past DENV infection would offer a convenient method for pre-vaccination screening at point-of-care. A systematic review was conducted to evaluate the performance of current dengue RDTs for determining dengue serostatus, using IgG antibodies against DENV as a marker of past infection. METHODS: PubMed and EMBASE databases were searched from 2000 to 2018 to identify studies evaluating dengue RDTs in individuals with known or possible previous DENV infection. Study quality was evaluated using GRADE and QUADAS-2 criteria. Semi-structured interviews were also performed with available dengue RDT manufacturers. RESULTS: The performance of four dengue IgG RDTs was determined in 3137 individuals across ten studies conducted in 13 countries, with serum used in most of the studies. No studies reported data for determining dengue serostatus, and limited data were available regarding cross-reactivity with other viruses. The majority of studies demonstrated sensitivities and specificities between 80% and 100% for dengue IgG detection in samples from secondary infection or convalescent time-points after recent infection. CONCLUSIONS: Although current dengue IgG RDTs have shown reasonable performance compared with laboratory-based tests in secondary infection, additional research is needed to determine how RDTs would perform in relevant populations targeted for vaccination. New RDTs or modifications to current RDTs are feasible and may optimize the performance of these tests for use in a pre-vaccination screening approach

Direct metallisation of polyetherimide substrates by activation with different metals

This article reports the performance of different metallic ions and nanoparticles (Ag, Cu, Ni, Pd, Cr, Co, Au and Fe) used as seed layers, formed by chemical or optical reduction, for the electroless Cu plating of metal tracks onto polyetherimide (PEI). Plated Cu performance was tested by adhesion, electrical conductivity, plating rate, XPS, SEM, XRD and EDX analysis. The application of Cu and Ag seeds resulted in high quality electroless Cu deposits presenting strong adhesion properties and high conductivity ((2.0 ± 0.5) × 107 S/m and (3.6 ± 0.2) × 107 S/m, respectively) compared with bulk copper (5.96 × 107 S/m). Performance is attributed to the high surface density and uniformity of seed layers. Of the metals, only Ag ions were photoreduced under the conditions applied and were subsequently used to electroless Cu plate high quality track features of 150 μm width. The application of sulphuric acid pre-treatment to PEI prior to Ag ion exchange, improved the photoinitiated track formation process, as demonstrated by a threefold increase to both photoinduced Ag nanoparticle density on the surface and electroless Cu plating rate, as well as improved electroless Cu adhesion to PEI

A rapid technique for the direct metallization of PDMS substrates for flexible and stretchable electronics applications

Metallization of a polydimethylsiloxane (PDMS)-based substrate is a challenge due to the difficulties in forming crack-free polymer and metal features using standard deposition techniques. Frequently, additional adhesion layers, rigid substrates, multiple processing steps (lift-off and etching) and expensive metal sputtering techniques are required, to achieve such metal patterns. This work presents a novel and rapid technique for the direct metallization of PDMS substrates using photolithography and electroless copper plating. The method has the advantage of not requiring expensive vacuum processing or multiple metallization steps. Electroless copper layer is demonstrated to have a strong adhesion to PDMS substrate with a high conductivity of (3.6 ± 0.7) × 107 S/m, which is close to the bulk copper (5.9 × 107 S/m). The copper-plated PDMS substrate displays mechanical and electrical stability whilst undergoing stretching deformations up to 10% due to applied strain. A functional electronic circuit was fabricated as a demonstration of the mechanical integrity of the copper-plated PDMS after bending

A review of aerosol jet printing—a non-traditional hybrid process for micro-manufacturing

Aerosol Jet Printing (AJP) is an emerging contactless direct write approach aimed at the production of fine features on a wide range of substrates. Originally developed for the manufacture of electronic circuitry, the technology has been explored for a range of applications, including, active and passive electronic components, actuators, sensors, as well as a variety of selective chemical and biological responses. Freeform deposition, coupled with a relatively large stand-off distance, is enabling researchers to produce devices with increased geometric complexity compared to conventional manufacturing or more commonly used direct write approaches. Wide material compatibility, high resolution and independence of orientation have provided novelty in a number of applications when AJP is conducted as a digitally driven approach for integrated manufacture. This overview of the technology will summarise the underlying principles of AJP, review applications of the technology and discuss the hurdles to more widespread industry adoption. Finally, this paper will hypothesise where gains may be realised through this assistive manufacturing process

Complexity of Bradley-Manna-Sipma Lexicographic Ranking Functions

In this paper we turn the spotlight on a class of lexicographic ranking functions introduced by Bradley, Manna and Sipma in a seminal CAV 2005 paper, and establish for the first time the complexity of some problems involving the inference of such functions for linear-constraint loops (without precondition). We show that finding such a function, if one exists, can be done in polynomial time in a way which is sound and complete when the variables range over the rationals (or reals). We show that when variables range over the integers, the problem is harder -- deciding the existence of a ranking function is coNP-complete. Next, we study the problem of minimizing the number of components in the ranking function (a.k.a. the dimension). This number is interesting in contexts like computing iteration bounds and loop parallelization. Surprisingly, and unlike the situation for some other classes of lexicographic ranking functions, we find that even deciding whether a two-component ranking function exists is harder than the unrestricted problem: NP-complete over the rationals and $\Sigma^P_2$-complete over the integers.Comment: Technical report for a corresponding CAV'15 pape

Reduction in the risk of human breast cancer by selective cyclooxygenase-2 (COX-2) inhibitors

BACKGROUND: Epidemiologic and laboratory investigations suggest that nonsteroidal anti-inflammatory drugs (NSAIDs) have chemopreventive effects against breast cancer due to their activity against cyclooxygenase-2 (COX-2), the rate-limiting enzyme of the prostaglandin cascade. METHODS: We conducted a case control study of breast cancer designed to compare effects of selective and non-selective COX-2 inhibitors. A total of 323 incident breast cancer patients were ascertained from the James Cancer Hospital, Columbus, Ohio, during 2003–2004 and compared with 649 cancer free controls matched to the cases at a 2:1 ratio on age, race, and county of residence. Data on the past and current use of prescription and over the counter medications and breast cancer risk factors were ascertained using a standardized risk factor questionnaire. Effects of COX-2 inhibiting agents were quantified by calculating odds ratios (OR) and 95% confidence intervals. RESULTS: Results showed significant risk reductions for selective COX-2 inhibitors as a group (OR = 0.29, 95% CI = 0.14–0.59), regular aspirin (OR = 0.49, 95% CI = 0.26–0.94), and ibuprofen or naproxen (0.36, 95% CI = 0.18–0.72). Acetaminophen, a compound with negligible COX-2 activity and low dose aspirin (81 mg) produced no significant change in the risk of breast cancer. CONCLUSION: Selective COX-2 inhibitors (celecoxib and rofecoxib) were only recently approved for use in 1999, and rofecoxib (Vioxx) was withdrawn from the marketplace in 2004. Nevertheless, even in the short window of exposure to these compounds, the selective COX-2 inhibitors produced a significant (71%) reduction in the risk of breast cancer, underscoring their strong potential for breast cancer chemoprevention

Taking a closer look at visual search: Just how feature-agnostic is singleton detection mode?

Singleton detection mode is a state in which spatial attention is set to prioritize any objects that differ from all other objects present on any feature dimension. Relatively little research has been devoted to confirming the consequences such a search mode has for stimulus processing. It is often implied that when observers employ singleton detection mode, all singletons capture attention equally, and when observers search for a single feature, only that feature captures attention. The experiment presented here contradicts these implications. We had observers search for colored singleton targets preceded by spatially uninformative colored singleton cues, and we recorded stimulus-evoked neural responses using electroencephalography (EEG). When observers had to respond to targets defined by two possible colors (a task intended to encourage singleton detection mode), cue validity effects were apparent for both target-color cues and irrelevant-color cues, and these effects were accompanied by an N2pc in the EEG data. Importantly, however, the target-color cues evoked significantly larger cue validity effects and N2pc components than did the irrelevant-color cues. In contrast, when observers had to respond to targets defined by one color (a task intended to encourage feature search mode), only cues of that color evoked a cue validity effect. Interestingly, the N2pcs produced by irrelevant cues did not differ between feature and singleton search, suggesting that the behavioral difference was not due to different attentional orienting. Rather, we suggest that behavioral singleton capture is due to a diminished same-location cost being produced by irrelevant-color cues

Cryotomography of budding influenza a virus reveals filaments with diverse morphologies that mostly do not bear a genome at their distal end

Influenza viruses exhibit striking variations in particle morphology between strains. Clinical isolates of influenza A virus have been shown to produce long filamentous particles while laboratory-adapted strains are predominantly spherical. However, the role of the filamentous phenotype in the influenza virus infectious cycle remains undetermined. We used cryo-electron tomography to conduct the first three-dimensional study of filamentous virus ultrastructure in particles budding from infected cells. Filaments were often longer than 10 microns and sometimes had bulbous heads at their leading ends, some of which contained tubules we attribute to M1 while none had recognisable ribonucleoprotein (RNP) and hence genome segments. Long filaments that did not have bulbs were infrequently seen to bear an ordered complement of RNPs at their distal ends. Imaging of purified virus also revealed diverse filament morphologies; short rods (bacilliform virions) and longer filaments. Bacilliform virions contained an ordered complement of RNPs while longer filamentous particles were narrower and mostly appeared to lack this feature, but often contained fibrillar material along their entire length. The important ultrastructural differences between these diverse classes of particles raise the possibility of distinct morphogenetic pathways and functions during the infectious process