Three-dimensional imaging of direct-written photonic structures

Third harmonic generation microscopy has been used to analyze the morphology of photonic structures created using the femtosecond laser direct-write technique. Three dimensional waveguide arrays and waveguide-Bragg gratings written in fused-silica and doped phosphate glass were investigated. A sensorless adaptive optical system was used to correct the optical aberrations occurring in the sample and microscope system, which had a lateral resolution of less than 500 nm. This non-destructive testing method creates volume reconstructions of photonic devices and reveals details invisible to other linear microscopy and index profilometry techniques.Comment: 8 pages, 3 color figures, 2 hyper-linked animation

Characterisation of the dynamic behaviour of lipid droplets in the early mouse embryo using adaptive harmonic generation microscopy

<p>Abstract</p> <p>Background</p> <p>Lipid droplets (LD) are organelles with an important role in normal metabolism and disease. The lipid content of embryos has a major impact on viability and development. LD in Drosophila embryos and cultured cell lines have been shown to move and fuse in a microtubule dependent manner. Due to limitations in current imaging technology, little is known about the behaviour of LD in the mammalian embryo. Harmonic generation microscopy (HGM) allows one to image LD without the use of exogenous labels. Adaptive optics can be used to correct aberrations that would otherwise degrade the quality and information content of images.</p> <p>Results</p> <p>We have built a harmonic generation microscope with adaptive optics to characterise early mouse embryogenesis. At fertilization, LD are small and uniformly distributed, but in the implanting blastocyst, LD are larger and enriched in the invading giant cells of the trophectoderm. Time-lapse studies reveal that LD move continuously and collide but do not fuse, instead forming aggregates that subsequently behave as single units. Using specific inhibitors, we show that the velocity and dynamic behaviour of LD is dependent not only on microtubules as in other systems, but also on microfilaments. We explore the limits within which HGM can be used to study living embryos without compromising viability and make the counterintuitive finding that 16 J of energy delivered continuously over a period of minutes can be less deleterious than an order of magnitude lower energy delivered dis-continuously over a period of hours.</p> <p>Conclusions</p> <p>LD in pre-implantation mouse embryos show a previously unappreciated complexity of behaviour that is dependent not only on microtubules, but also microfilaments. Unlike LD in other systems, LD in the mouse embryo do not fuse but form aggregates. This study establishes HGM with adaptive optics as a powerful tool for the study of LD biology and provides insights into the photo-toxic effects of imaging embryos.</p

The MATHUSLA Test Stand

The rate of muons from LHC $pp$ collisions reaching the surface above the ATLAS interaction point is measured and compared with expected rates from decays of $W$ and $Z$ bosons and $b$- and $c$-quark jets. In addition, data collected during periods without beams circulating in the LHC provide a measurement of the background from cosmic ray inelastic backscattering that is compared to simulation predictions. Data were recorded during 2018 in a 2.5 $\times$ 2.5 $\times$ 6.5~$\rm{m}^3$ active volume MATHUSLA test stand detector unit consisting of two scintillator planes, one at the top and one at the bottom, which defined the trigger, and six layers of RPCs between them, grouped into three $(x,y)$-measuring layers separated by 1.74 m from each other. Triggers selecting both upward-going tracks and downward-going tracks were used.Comment: 18 pages, 11 figures, 1 tabl

Why Quantification Matters: Characterization of Phenotypes at the <em>Drosophila</em> Larval Neuromuscular Junction

Most studies on morphogenesis rely on qualitative descriptions of how anatomical traits are affected by the disruption of specific genes and genetic pathways. Quantitative descriptions are rarely performed, although genetic manipulations produce a range of phenotypic effects and variations are observed even among individuals within control groups. Emerging evidence shows that morphology, size and location of organelles play a previously underappreciated, yet fundamental role in cell function and survival. Here we provide step-by-step instructions for performing quantitative analyses of phenotypes at the Drosophila larval neuromuscular junction (NMJ). We use several reliable immuno-histochemical markers combined with bio-imaging techniques and morphometric analyses to examine the effects of genetic mutations on specific cellular processes. In particular, we focus on the quantitative analysis of phenotypes affecting morphology, size and position of nuclei within the striated muscles of Drosophila larvae. The Drosophila larval NMJ is a valuable experimental model to investigate the molecular mechanisms underlying the structure and the function of the neuromuscular system, both in health and disease. However, the methodologies we describe here can be extended to other systems as well

Light-driven transformation of biomass into chemicals using photocatalysts – Vistas and challenges

Lignocellulosic biomass has become an important sustainable resource for fuels, chemicals and energy. It is an attractive source for alternative fuels and green chemicals because it is non-edible and widely available in the planet in huge volumes. The use of biomass as starting material to produce fuels and chemicals leads to closed carbon cycle and promotes circular economy. Although there are many thermo-chemical methods such as pyrolysis, liquefaction and gasification close at hand for processing lignocellulosic biomass and transforming the derived compounds into valuable chemicals and fuels, the photocatalytic method is more advantageous as it utilizes light and ambient conditions for reforming the said compounds. Appraisal of recent literature indicates a variety of photocatalytic systems involving different catalysts, reactors and conditions studied for this purpose. This article reviews the recent developments on the photocatalytic oxidation of biomass and its derivatives into value-added chemicals. The nature of the biomass and derived molecules, nature of the photocatalysts, efficiency of the photocatalysts in terms of conversion and selectivity, influence of reaction conditions and light sources, effect of additives and mechanistic pathways are discussed. Importance has been given also to discuss the complementary technologies that could be coupled with photocatalysis for better conversion of biomass and biomass-derived molecules to value-added chemicals. A summary of these aspects, conclusions and future prospects are given in the end

Genomic regions associated with salinity stress tolerance in tropical maize (Zea Mays L.)

Being a widely cultivated crop globally under diverse climatic conditions and soil types, maize is often exposed to an array of biotic and abiotic stresses. Soil salinity is one of the challenges for maize cultivation in many parts of lowland tropics that significantly affects crop growth and reduces economic yields. Breeding strategies integrated with molecular approach might accelerate the process of identifying and developing salinity-tolerant maize cultivars. In this study, an association mapping panel consisting of 305 diverse maize inbred lines was phenotyped in a managed salinity stress phenotyping facility at International Center for Biosaline Agriculture (ICBA), Dubai, United Arab Emirates (UAE). Wide genotypic variability was observed in the panel under salinity stress for key phenotypic traits viz., grain yield, days to anthesis, anthesis-silking interval, plant height, cob length, cob girth, and kernel number. The panel was genotyped following the genome-based sequencing approach to generate 955,690 SNPs. Total SNPs were filtered to 213,043 at a call rate of 0.85 and minor allele frequency of 0.05 for association analysis. A total of 259 highly significant (P ≤ 1 × 10–5) marker-trait associations (MTAs) were identified for seven phenotypic traits. The phenotypic variance for MTAs ranged between 5.2 and 9%. A total of 64 associations were found in 19 unique putative gene expression regions. Among them, 12 associations were found in gene models with stress-related biological functions

Cultural Humility: A Collaborative Approach to Recruiting Patients with Deliberate Self-Harm into a Multi-Hospital Randomized Controlled Trial

Objectives: The ‘SMS SOS’ Deliberate Self-Harm (DSH) Aftercare Study was conducted in Western Sydney, Australia (October 2017 to December 2020) across three large public hospitals. During this randomized controlled trial (RCT), it was observed that knowledge exchange between key stakeholders and their ‘cultural’ perspectives (for example, Mental Health Clinicians, Lived Experience Mental Health Consultants—Patient Representatives, Administrative Officers, and Researchers) was essential to effective recruitment of patients experiencing DSH. Knowledge exchange within and between cultural groups was maximised and assessed using a communication matrix. This process, transferable to other trials engaging multiple ‘cultures’, aimed to promote the early identification of wider-team strengths as well as active management of emergent issues that would otherwise impede patient recruitment, and to maximise funding and human resources. Methods: A descriptive study was conducted with a convenience sample of team members who represented different cultures in the study. Qualitative data were elicited from a ‘know and tell’ matrix. Through an iterative process, themes were generated that encapsulated what team members needed to know from and tell to their colleagues concerning the study. Results: Factors that impacted participation in the study included clinician workload, the level of motivation/ commitment/confidence of clinicians to recruit patients, clinician-patient engagement, perception and expectations of study involvement, inter-cultural communication, and clinician training and support. The findings of this multidisciplinary consultation informed a composite model of knowledge exchange and the development of educational briefing/ orientation modules that make explicit team members’ roles and responsibilities to foster group member participation and enhance patient recruitment. Conclusions: It is incumbent upon multidisciplinary team members of large-scale studies to adopt a similar ‘knowledge exchange’ strategy early in the planning and design stage. Adoption of such a strategy has the potential to mitigate risk of delay in project timelines, improve project outcomes, and ensure the efficient use of research funding, particularly in newly established research teams within clinical settings and with members newer to formal research collaborations. Keywords: cultural humility; deliberate self-harm; engagement; participant recruitment; participatory research; randomized controlled tria

High-Speed CMOS-Free Purely Spintronic Asynchronous Recurrent Neural Network

Neuromorphic computing systems overcome the limitations of traditional von Neumann computing architectures. These computing systems can be further improved upon by using emerging technologies that are more efficient than CMOS for neural computation. Recent research has demonstrated memristors and spintronic devices in various neural network designs boost efficiency and speed. This paper presents a biologically inspired fully spintronic neuron used in a fully spintronic Hopfield RNN. The network is used to solve tasks, and the results are compared against those of current Hopfield neuromorphic architectures which use emerging technologies