Multimode fibre:Light-sheet microscopy at the tip of a needle

We also thank the UK Engineering and Physics Sciences Research Council for funding under grant EP/J01771X/1. Finally, we would like to thank EXCELLENT TEAMS (CZ.1.07/2.3.00/30.0005) from European Social Fund and CEITEC - Central European Institute of Technology (CZ.1.05/1.1.00/02.0068) from European Regional Development Fund for support.Light-sheet fluorescence microscopy has emerged as a powerful platform for 3-D volumetric imaging in the life sciences. Here, we introduce an important step towards its use deep inside biological tissue. Our new technique, based on digital holography, enables delivery of the light-sheet through a multimode optical fibre - an optical element with extremely small footprint, yet permitting complex control of light transport processes within. We show that this approach supports some of the most advanced methods in light-sheet microscopy: by taking advantage of the cylindrical symmetry of the fibre, we facilitate the wavefront engineering methods for generation of both Bessel and structured Bessel beam plane illumination. Finally, we assess the quality of imaging on a sample of fluorescent beads fixed in agarose gel and we conclude with a proof-of-principle imaging of a biological sample, namely the regenerating operculum prongs of Spirobranchus lamarcki.Publisher PDFPeer reviewe

Persistent Place-Making in Prehistory: the Creation, Maintenance, and Transformation of an Epipalaeolithic Landscape

Most archaeological projects today integrate, at least to some degree, how past people engaged with their surroundings, including both how they strategized resource use, organized technological production, or scheduled movements within a physical environment, as well as how they constructed cosmologies around or created symbolic connections to places in the landscape. However, there are a multitude of ways in which archaeologists approach the creation, maintenance, and transformation of human-landscape interrelationships. This paper explores some of these approaches for reconstructing the Epipalaeolithic (ca. 23,000–11,500 years BP) landscape of Southwest Asia, using macro- and microscale geoarchaeological approaches to examine how everyday practices leave traces of human-landscape interactions in northern and eastern Jordan. The case studies presented here demonstrate that these Epipalaeolithic groups engaged in complex and far-reaching social landscapes. Examination of the Early and Middle Epipalaeolithic (EP) highlights that the notion of “Neolithization” is somewhat misleading as many of the features we use to define this transition were already well-established patterns of behavior by the Neolithic. Instead, these features and practices were enacted within a hunter-gatherer world and worldview

Roadmap on multimode light shaping

Our ability to generate new distributions of light has been remarkably enhanced in recent years. At the most fundamental level, these light patterns are obtained by ingeniously combining different electromagnetic modes. Interestingly, the modal superposition occurs in the spatial, temporal as well as spatio-temporal domain. This generalized concept of structured light is being applied across the entire spectrum of optics: generating classical and quantum states of light, harnessing linear and nonlinear light-matter interactions, and advancing applications in microscopy, spectroscopy, holography, communication, and synchronization. This Roadmap highlights the common roots of these different techniques and thus establishes links between research areas that complement each other seamlessly. We provide an overview of all these areas, their backgrounds, current research, and future developments. We highlight the power of multimodal light manipulation and want to inspire new eclectic approaches in this vibrant research community.acceptedVersionPeer reviewe

Are high-intensity zones and Modic changes mutually exclusive in symptomatic lumbar degenerative discs?

Object: Modic changes (MCs) and high-intensity zones (HIZs) potentially serve as variably sensitive markers for discogenic chronic low-back pain (CLBP). No study has hitherto assessed the phenomenon of MC-HIZ coexistence at a single level, and the goal in this study was to assess the nature and frequency of this phenomenon. Methods: One hundred twenty consecutive patients with discogenic CLBP in whom lumbar MR imaging studies had demonstrated an HIZ, an MC, or both were included. Results: This cohort (120 consecutive patients with 193 degenerative discs) had discogenic CLBP in at least 1 lumbar level associated with either an HIZ (77 discs), an MC (67 discs), or both (16 patients); there were 55 coexistent non-HIZ/non-MC degenerative discs. Painful MC-HIZ coexistence at 1 level occurred in 6 patients (5 of whom were female). If HIZs and MCs were random, independent entities, then MC-HIZ coexistence at 1 level would have been expected in 67 × 77/193 (that is, 27) discs. The observed frequency was therefore significantly lower (χ2 = 41, p < 0.001). There were no significant demographic differences between groups. The HIZ disc height (8 ± 0.2 mm) was significantly greater than the MC (6.6 ± 0.2 mm) or MC-HIZ (6.7 ± 0.2 mm) disc heights (p < 0.001). Conclusions: In patients with discogenic CLBP associated with HIZ or MC lesions, MC-HIZ coexistence at 1 level was significantly rarer than expected even by chance; thus, despite both being manifestations of a seemingly common degenerative process, HIZ and MC more closely represent “either/or” phenomena. Because HIZ disc height was significantly greater, HIZs may develop earlier in the disc degenerative ontogeny. If any degenerative disc may only display an HIZ first, yet may ultimately display an MC instead, then HIZs must invariably regress as MCs supervene (or even vice versa). The MC-HIZ coexistence would therefore represent either a rare stable state (possibly more common in females) or a transitory state, as one lesion gradually replaces the other. Longitudinal studies would confirm or refute these hypotheses, although significantly larger sample sizes would be required.Laurence A.G. Marshman, Andrew V. Metcalfe, Manoj Krishna, and Tai Friese

Two photon fluorescence sensors based on resonant grating waveguide structures

Abstract We use novel high-finesse polymeric resonant grating waveguide structures (GWS) for strong enhancement of two photon fluorescence (TPF). At a specific wavelength and angular orientation of the incident beam, the grating waveguide structure resonates. This resonance results in a field enhancement at the surface that can be exploited for TPF spectroscopy, without the need for highly focused laser excitation light. We compare the TPF obtained from a thin layer of tetramethylrhodamine (TMR) deposited on top of a GWS at resonance and off-resonance. Our procedure and results indicate that the detection of TPF can indeed be improved with the resonant GWS by at least fifteen times. These results have been also demonstrated using a GWS and a 2 m thick layer of TMR aqueous solution

Two photon fluorescence sensors based on resonant grating waveguide structures

Abstract We use novel high-finesse polymeric resonant grating waveguide structures (GWS) for strong enhancement of two photon fluorescence (TPF). At a specific wavelength and angular orientation of the incident beam, the grating waveguide structure resonates. This resonance results in a field enhancement at the surface that can be exploited for TPF spectroscopy, without the need for highly focused laser excitation light. We compare the TPF obtained from a thin layer of tetramethylrhodamine (TMR) deposited on top of a GWS at resonance and off-resonance. Our procedure and results indicate that the detection of TPF can indeed be improved with the resonant GWS by at least fifteen times. These results have been also demonstrated using a GWS and a 2 m thick layer of TMR aqueous solution

Site formation processes of outdoor spaces in tropical environments: a micro-geoarchaeological case study from backyard Lo Gach, southern Vietnam

In the tropics, outdoor areas are important arenas of social life and the scene of economic and daily activities. Yet, outdoor areas are not often detected due to destructive post-depositional processes and low archaeological visibility. Here, we use microarchaeology to establish the settlement history and outdoor use of space at Lo Gach in Long An Province, southern Vietnam. The radiocarbon chronology identifies two phases of occupation: an initial presence at 3300–3000 cal. BP and later activity at 2750–2400 cal. BP. Microarchaeological analysis of the stratigraphy reveals complex sequences of organic waste severely transformed by chemical diagenesis. The results indicate that the excavated area at Lo Gach was an outdoor ‘backyard’ containing external surfaces utilised for a range of activities including rice processing, disposal of combustion residues, in situ burning, and recurrent foot traffic. Intensified rice agriculture and the systematic management of organic waste were the main structuring rhythms of social life that were performed at the Lo Gach settlement