Si-doped zinc oxide transparent conducting oxides; Nanoparticle optimisation, scale-up and thin film deposition

Silicon-doped zinc oxide, Zn 1-x Si x O y , transparent conducting oxide nanoparticles were prepared using a laboratory scale (production rate of 60 g h -1 ) continuous hydrothermal flow synthesis (CHFS) process in the dopant range 0.25 to 3.0 at% Si. The resistivity of the materials was assessed as pressed heat-treated pellets, revealing that the sample with the lowest resistivity (3.5 × 10 -2 Ω cm) was the 0.25 at% Si doped ZnO sample. The synthesis of this optimum composition was then scaled up to 350 g h -1 using a larger pilot plant CHFS process. Spin coating of a slurry of the resulting nanopowder made on the pilot plant, followed by an appropriate heat-treatment, produced a thin film with an optical transmission > 80% and a low resistivity of 2.4 × 10 -3 Ω cm, with a carrier concentration of 1.02 × 10 20 cm -3 and a mobility of 11 cm 2 V -1 s -1 . This is a factor of almost twenty times improvement in the resistivity versus the analogous pressed, heat-treated pellet

Edible crabs “Go West”: migrations and incubation cycle of Cancer pagurus revealed by electronic tags

Crustaceans are key components of marine ecosystems which, like other exploited marine taxa, show seasonable patterns of distribution and activity, with consequences for their availability to capture by targeted fisheries. Despite concerns over the sustainability of crab fisheries worldwide, difficulties in observing crabs’ behaviour over their annual cycles, and the timings and durations of reproduction, remain poorly understood. From the release of 128 mature female edible crabs tagged with electronic data storage tags (DSTs), we demonstrate predominantly westward migration in the English Channel. Eastern Channel crabs migrated further than western Channel crabs, while crabs released outside the Channel showed little or no migration. Individual migrations were punctuated by a 7-month hiatus, when crabs remained stationary, coincident with the main period of crab spawning and egg incubation. Incubation commenced earlier in the west, from late October onwards, and brooding locations, determined using tidal geolocation, occurred throughout the species range. With an overall return rate of 34%, our results demonstrate that previous reluctance to tag crabs with relatively high-cost DSTs for fear of loss following moulting is unfounded, and that DSTs can generate precise information with regards life-history metrics that would be unachievable using other conventional means

Cross-talk and interference enhance information capacity of a signaling pathway

A recurring motif in gene regulatory networks is transcription factors (TFs) that regulate each other, and then bind to overlapping sites on DNA, where they interact and synergistically control transcription of a target gene. Here, we suggest that this motif maximizes information flow in a noisy network. Gene expression is an inherently noisy process due to thermal fluctuations and the small number of molecules involved. A consequence of multiple TFs interacting at overlapping binding-sites is that their binding noise becomes correlated. Using concepts from information theory, we show that in general a signaling pathway transmits more information if 1) noise of one input is correlated with that of the other, 2) input signals are not chosen independently. In the case of TFs, the latter criterion hints at up-stream cross-regulation. We demonstrate these ideas for competing TFs and feed-forward gene regulatory modules, and discuss generalizations to other signaling pathways. Our results challenge the conventional approach of treating biological noise as uncorrelated fluctuations, and present a systematic method for understanding TF cross-regulation networks either from direct measurements of binding noise, or bioinformatic analysis of overlapping binding-sites.Comment: 28 pages, 5 figure

High-Throughput Continuous Hydrothermal Synthesis of Transparent Conducting Aluminum and Gallium Co-doped Zinc Oxides

High-throughput continuous hydrothermal flow synthesis was used to generate a library of aluminum and gallium-codoped zinc oxide nanoparticles of specific atomic ratios. Resistivities of the materials were determined by Hall Effect measurements on heat-treated pressed discs and the results collated into a conductivity-composition map. Optimal resistivities of ∼9 × 10–3 Ω cm were reproducibly achieved for several samples, for example, codoped ZnO with 2 at% Ga and 1 at% Al. The optimum sample on balance of performance and cost was deemed to be ZnO codoped with 3 at% Al and 1 at% Ga

Conducting Al and Ga-doped zinc oxides; rapid optimisation and scale-up

A high-throughput synthesis, screening and subsequent scale-up approach was utilised for the optimisation of conductive aluminium and gallium-doped zinc oxide (AZO and GZO, respectively) nanoparticles. AZO and GZO nanoparticles with up to 6 at% dopant (with respect to Zn) were directly synthesised using a laboratory scale continuous hydrothermal process at a rate of 60 g per hour. The resistivities were determined by Hall effect measurements on pressed, heat-treated discs. Both Al- and Ga-doping yielded resistivities of the order of 1 × 10−2 Ω cm for most samples; the lowest resistivity of AZO was 7.0 × 10−3 Ω cm (at 2.5 at% Al doping), and the lowest resistivity of GZO was 9.1 × 10−3 Ω cm (at 3.5 at% Ga doping), which are considered exceptionally conductive for pressed nanopowders. Synthesis of the optimised lab-scale compositions was scaled-up using a pilot-scale continuous hydrothermal process at a production rate of 8 kg per day (by dry mass); results obtained from these nanopowders generally retained resistivity trends observed for the lab-scale analogues

Maternal Benzodiazepines and Z-Drugs Use during Pregnancy and Adverse Birth and Neurodevelopmental Outcomes in Offspring:A Population-Based Cohort Study

Introduction: The use of benzodiazepines and/or z-drugs in women of childbearing age has increased. Objective: The aim of the study was to evaluate whether gestational benzodiazepine and/or z-drug exposure is associated with adverse birth and neurodevelopmental outcomes. Methods: A population-based cohort including mother-child pairs from 2001 to 2018 in Hong Kong was analysed to compare gestationally exposed and nonexposed children on the risk of preterm birth, small for gestational age, autism spectrum disorder (ASD), and attention-deficit/hyperactivity disorder (ADHD) through logistic/Cox proportional hazards regression with a 95% confidence interval (CI). Sibling-matched analyses and negative control analyses were applied. Results: When comparing gestationally exposed with gestationally nonexposed children, the weighted odds ratio (wOR) was 1.10 (95% CI = 0.97-1.25) for preterm birth and 1.03 (95% CI = 0.76-1.39) for small for gestational age, while the weighted hazard ratio (wHR) was 1.40 (95% CI = 1.13-1.73) for ASD and 1.15 (95% CI = 0.94-1.40) for ADHD. Sibling-matched analyses showed no association between gestationally exposed children and their gestationally nonexposed siblings for all outcomes (preterm birth: wOR = 0.84, 95% CI = 0.66-1.06; small for gestational age: wOR = 1.02, 95% CI = 0.50-2.09; ASD: wHR = 1.10, 95% CI = 0.70-1.72; ADHD: wHR = 1.04, 95% CI = 0.57-1.90). Similarly, no significant differences were observed when comparing children whose mothers took benzodiazepines and/or z-drugs during pregnancy to children whose mothers took benzodiazepines and/or z-drugs before but not during pregnancy for all outcomes. Conclusions: The findings do not support a causal relationship between gestational benzodiazepines and/or z-drugs exposure and preterm birth, small for gestational age, ASD, or ADHD. Clinicians and pregnant women should carefully balance the known risks of benzodiazepines and/or z-drugs use against those of untreated anxiety and sleep problems.</p

Maternal benzodiazepines and z-drugs use during pregnancy and adverse birth and neurodevelopmental outcomes in offspring: a population-based cohort study

Introduction: The use of benzodiazepines and/or z-drugs in women of childbearing age has increased. / Objective: To evaluate whether gestational benzodiazepines and/or z-drugs exposure is associated with adverse birth and neurodevelopmental outcomes. / Methods: A population-based cohort including mother-child pairs from 2001–2018 in Hong Kong was analysed to compared gestationally exposed and nonexposed children on the risk of preterm birth, small for gestational age, autism spectrum disorder (ASD), and attention-deficit/hyperactivity disorder (ADHD) through logistic/Cox proportional hazards regression. Sibling-matched analyses and negative control analyses were applied. / Results: When comparing gestationally exposed with gestationally nonexposed children, the weighted odds ratio (wOR) was 1.10 (95%CI=0.97–1.25) for preterm birth and 1.03 (95%CI=0.76–1.39) for small for gestational age while the weighted hazard ratio (wHR) was 1.40 (95%CI=1.13–1.73) for ASD and 1.15 (95%CI=0.94–1.40) for ADHD. Sibling-matched analyses showed no association between gestationally exposed children and their gestationally nonexposed siblings for all outcomes (preterm birth: wOR=0.84, 95%CI=0.66–1.06; small for gestational age: wOR=1.02, 95%CI=0.50–2.09; ASD: wHR=1.10, 95%CI=0.70–1.72; ADHD: wHR=1.04, 95%CI=0.57–1.90). Similarly, no significant differences were observed when comparing children whose mothers took benzodiazepines and/or z-drugs during pregnancy to children whose mothers took benzodiazepines and/or z-drugs before but not during pregnancy for all outcomes. / Conclusions: The findings do not support a causal relationship between gestational benzodiazepines and/or z-drugs exposure and preterm birth, small for gestational age, ASD, or ADHD. Clinicians and pregnant women should carefully balance the known risks of benzodiazepines and/or z-drugs use against that of untreated anxiety and sleep problems

Viruses causing lower respiratory symptoms in young children: Findings from the ORChID birth cohort

© 2018 Article author(s). Introduction Viral acute respiratory infections (ARIs) cause substantial child morbidity. Sensitive molecular-based assays aid virus detection, but the clinical significance of positive tests remains uncertain as some viruses may be found in both acutely ill and healthy children. We describe disease-pathogen associations of respiratory viruses and quantify virus-specific attributable risk of ARIs in healthy children during the first 2 years of life. Methods One hundred fifty-eight term newborn babies in Brisbane, Australia, were recruited progressively into a longitudinal, community-based, birth cohort study conducted between September 2010 and October 2014. A daily tick-box diary captured predefined respiratory symptoms from birth until their second birthday. Weekly parent-collected nasal swabs were batch-tested for 17 respiratory viruses by PCR assays, allowing calculation of virus-specific attributable fractions in the exposed (AFE) to determine the proportion of virus-positive children whose ARI symptoms could be attributed to that particular virus. Results Of 8100 nasal swabs analysed, 2646 (32.7%) were virus-positive (275 virus codetections, 3.4%), with human rhinoviruses accounting for 2058/2646 (77.8%) positive swabs. Viruses were detected in 1154/1530 (75.4%) ARI episodes and in 984/4308 (22.8%) swabs from asymptomatic periods. Respiratory syncytial virus (AFE: 68% (95% CI 45% to 82%)) and human metapneumovirus (AFE: 69% (95% CI 43% to 83%)) were strongly associated with higher risk of lower respiratory symptoms. Discussion The strong association of respiratory syncytial virus and human metapneumovirus with ARIs and lower respiratory symptoms in young children managed within the community indicates successful development of vaccines against these two viruses should provide substantial health benefits

A demonstration of 'broken' visual space

It has long been assumed that there is a distorted mapping between real and ‘perceived’ space, based on demonstrations of systematic errors in judgements of slant, curvature, direction and separation. Here, we have applied a direct test to the notion of a coherent visual space. In an immersive virtual environment, participants judged the relative distance of two squares displayed in separate intervals. On some trials, the virtual scene expanded by a factor of four between intervals although, in line with recent results, participants did not report any noticeable change in the scene. We found that there was no consistent depth ordering of objects that can explain the distance matches participants made in this environment (e.g. A > B > D yet also A < C < D) and hence no single one-to-one mapping between participants’ perceived space and any real 3D environment. Instead, factors that affect pairwise comparisons of distances dictate participants’ performance. These data contradict, more directly than previous experiments, the idea that the visual system builds and uses a coherent 3D internal representation of a scene

Increased corpus callosum volume in children with chromosome 22q11.2 deletion syndrome is associated with neurocognitive deficits and genetic polymorphisms

Chromosome 22q11.2 deletion syndrome (22q11DS) is associated with neurocognitive impairments. The neural substrates of cognitive impairments in 22q11DS remain poorly understood. Because the corpus callosum (CC) is found to be abnormal in a variety of neurodevelopmental disorders, we obtained volumetric measurements of the CC and its subregions, examined the relationship between these regions and neurocognition and selected genotypes within candidate genes in the 22q11.2 interval in 59 children with 22q11DS and 53 control subjects. The total CC, splenium and genu were significantly larger in children with 22q11DS and the enlargement was associated with better neurocognitive functioning in the 22q11DS group, suggestive of a compensatory increase in the CC volumes. The expected age-related increase in the volume of the CC was not seen in children with 22q11DS, indicative of dysmaturation of the CC in these children. The increased volumes in the genu, splenium and total CC in the 22q11DS group were associated with polymorphisms within the candidate genes: COMT (rs4680), ZDHHC8 (rs175174) and UFD1L (rs5992403). These findings indicate that alterations in the CC volume in children with 22q11DS are associated with cognition and specific genotypes in the 22q11.2 interval