The cryopreservation of human semen, and subsequent evaluation of a commercially-available device to isolate motile sperm

The cryopreservation of human semen is a vital asset in assisted reproductive technologies (ART). Although advances have been in the freezing of sperm, further refinement is both necessary and ongoing. Computer-assisted semen analysis (CASA) has been increasingly utilised in both research and diagnostic however there are a range of variables that must first be controlled in order to produce reliable measurements. Following thawing, sperm must be isolated from both the original seminal plasma and the cryoprotectants; the two most used isolation methods include density gradient centrifugation (DGC) and the swim-up method. The present thesis sought to investigate the following areas (i) a technical validation phase investigating variables that can influence CASA measurements (ii) the effect of neat glycerol and a commercial cryoprotective medium (CPM) upon sperm motility prior to cryopreservation, and subsequent effects of diluting these samples (iii) the effectiveness of neat glycerol versus a CPM in the post-thaw recovery of motile sperm, and (iv) the effectiveness of DGC, a direct swim-up procedure and a commercial device that utilises the swim-up procedure. Several variables were identified in the measuring of semen samples in conjunction with CASA software. Firstly the use of a capillary-loading chamber was found to result in decreased levels of total and progressive motility, as well as reduced kinematic parameters when compared to a droplet-loaded configuration. The time between the loading of a sample was found to be stable at the 2 minute time interval, and as such this was set for all measurements in the study. Finally, operator-corrections were discovered to be crucial in not only accurately measuring sperm concentration, but also sperm motility. The commercial CPM containing glycerol had the least toxic effect on sperm motility pre-cryopreservation. There was a linear relationship between decreased sperm motility and increased presence of glycerol, as demonstrated by 10% v/v glycerol addition. The further dilution of glycerol-containing semen samples with two common gamete handling media were found to cause a further significant reduction in sperm motility, whereas in contrast seminal plasma was not found to reduce sperm motility in these samples. The CPM was found to have the greatest yield of cryopreserved motile sperm post-thaw when compared to glycerol at both 5 and 10% v/v. Finally, DGC yielded increased concentrations of sperm post-isolation, but with a reduced level of motility (10.2M/ml and 20% progressive motility respectively), whereas both the swim-up methods had reduced levels of concentration (1.8M/ml for the standard swim-up, and 1.5M/ml for the commercial device) but with increased levels of progressive motility (39.1% and 42.8% respectively for the standard swim-up and commercial device). In summary, CASA software is able to provide reliable results given the chamber type is controlled and that operator-corrections are applied. Secondly, glycerol has a complex relationship with the cryosurvivability of spermatozoa and the toxic effects it exerts on them. Glycerol toxicity appeared dose-dependent, with decreased sperm motility with increased glycerol presence, both pre and post-cryopreservation/thawing. Finally, the most effective isolation technique for frozen-thawed sperm is dependent on what ART procedure is to be undertaken

Autonomous Operation and Human-Robot Interaction on an Indoor Mobile Robot

MARVIN (Mobile Autonomous Robotic Vehicle for Indoor Navigation) was once the flagship of Victoria University’s mobile robotic fleet. However, over the years MARVIN has become obsolete. This thesis continues the the redevelopment of MARVIN, transforming it into a fully autonomous research platform for human-robot interaction (HRI). MARVIN utilises a Segway RMP, a self balancing mobility platform. This provides agile locomotion, but increases sensor processing complexity due to its dynamic pitch. MARVIN’s existing sensing systems (including a laser rangefinder and ultrasonic sensors) are augmented with tactile sensors and a Microsoft Kinect v2 RGB-D camera for 3D sensing. This allows the detection of the obstacles often found in MARVIN’s unmodified office-like operating environment. These sensors are processed using novel techniques to account for the Segway’s dynamic pitch. A newly developed navigation stack takes the processed sensor data to facilitate localisation, obstacle detection and motion planning. MARVIN’s inherited humanoid robotic torso is augmented with a touch screen and voice interface, enabling HRI. MARVIN’s HRI capabilities are demonstrated by implementing it as a robotic guide. This implementation is evaluated through a usability study and found to be successful. Through evaluations of MARVIN’s locomotion, sensing, localisation and motion planning systems, in addition to the usability study, MARVIN is found to be capable of both autonomous navigation and engaging HRI. These developed features open a diverse range of research directions and HRI tasks that MARVIN can be used to explore

How does perinatal maternal mental health explain early social inequalities in child behavioural and emotional problems? Findings from the Wirral Child Health and Development Study

This study aimed to assess how maternal mental health mediates the association between childhood socio-economic conditions at birth and subsequent child behavioural and emotional problem scores. Analysis of the Wirral Child Health and Development Study (WCHADS), a prospective epidemiological longitudinal study of the early origins of child mental health (n = 664). Household income at 20-weeks gestation, a measure of socio-economic conditions (SECs) in pregnancy, was the main exposure. The outcome measure was externalising and internalising problems, as measured by the Child Behaviour Checklist at 5 years. We assessed the association of household income with child behavioural outcomes in sequential linear models adjusting for maternal mental health in the pre- and post- natal period. Children of mothers in more disadvantaged households had higher scores for externalising behaviour with a difference of 3.6 points comparing the most affluent to the most disadvantaged families (the socio-economic (SEC) gap). In our regression model adjusting for baseline confounders, comparing children of mothers in the most disadvantaged households to the least disadvantaged, we found that most disadvantaged children scored 45 percentage points (95% CI 9, 93) higher for externalising problems, and 42% of this difference was explained in the fully adjusted model. Adjusting for prenatal maternal depressive symptomology attenuated the SEC gap in externalising problems by about a third, rendering the association non-significant, whilst adjusting for pre- and post-natal maternal mental health attenuated the SEC gap by 42%. There was no significant relationship between household income and internalising problems. Social disadvantage is associated with higher child externalising behaviour problems score at age 5, and about 40% of this was explained by maternal perinatal mental health. Policies supporting maternal mental health in pregnancy are important to address the early emergence of inequalities in child mental health

Research Plan 2023–2025

Snow avalanches are a frequent and significant natural hazard in Norway. Each year, avalanche events result in fatalities, evacuations, interruptions, and damage to infrastructure networks such as roads, railways, and electrical transmission lines. This combines to a substantial impact on the livelihoods of the people living and working in mountainous areas or also along the fjords in Norway. Persistent avalanche hazard in steep terrain is a major factor considered during land-use planning and development. During the snow season, variations in the avalanche danger identified in regional and site-specific bulletins influence the operation of the transportation networks and the safety of workers in these areas. Applied research on avalanches and their societal impacts has been conducted at the Norwegian Geotechnical Institute (NGI) since 1973. The year 2023 will mark the 50 years anniversary of this research project. The research has been funded in part by an annual grant from the Norwegian parliament administered by the Norwegian Water Resources and Energy Directorate (NVE). Recent research activities have improved our understanding of avalanche formation, movement and impacts from avalanches. For example, enhanced knowledge of the individual processes leading to avalanche initiation, avalanche dynamics and avalanche impacts have been applied to develop tools for prediction of avalanche events, runout distance and impact pressures. While much has been accomplished within the avalanche research community in recent years, many key questions remain. Research in this area becomes increasingly important as a changing climate will vary the frequency and behaviour of avalanche events. In addition, the transfer of resent research outcomes into common practise is an ongoing challenge which needs continuous attention. This project plan will: Present the research goals for the 2023–2025 period. Outline the project organisation. Present the work-package structure and specific research tasks to be undertaken by the applied avalanche research group at NGI over the next three years.NVE (Norges vassdrags- og energidirektorat

Plankton community respiration and bacterial metabolism in a North Atlantic Shelf Sea during spring bloom development (April 2015)

Spring phytoplankton blooms are important events in Shelf Sea pelagic systems as the increase in carbon production results in increased food availability for higher trophic levels and the export of carbon to deeper waters and the sea-floor. It is usually accepted that the increase in phytoplankton abundance and production is followed by an increase in plankton respiration. However, this expectation is derived from field studies with a low temporal sampling resolution (5–15 days). In this study we have measured the time course of plankton abundance, gross primary production, plankton community respiration, respiration of the plankton size classes (>0.8 µm and 0.2–0.8 µm) and bacterial production at ≤5 day intervals during April 2015 in order to examine the phasing of plankton autotrophic and heterotrophic processes. Euphotic depth-integrated plankton community respiration increased five-fold (from 22 ± 4 mmol O2 m−2 d−1 on 4th April to 119 ± 4 mmol O2 m−2 d−1 on 15th April) at the same time as gross primary production also increased five-fold, (from 114 ± 5 to 613 ± 28 mmol C m−2 d−1). Bacterial production began to increase during the development of the bloom, but did not reach its maximum until 5 days after the peak in primary production and plankton respiration. The increase in plankton community respiration was driven by an increase in the respiration attributable to the >0.8 µm size fraction of the plankton community (which would include phytoplankton, microzooplankton and particle attached bacteria). Euphotic depth-integrated respiration of the 0.2–0.8 µm size fraction (predominantly free living bacteria) decreased and then remained relatively constant (16 ± 3 – 11 ± 1 mmol O2 m−2 d−1) between the first day of sampling (4th April) and the days following the peak in chlorophyll-a (20th and 25th April). Recent locally synthesized organic carbon was more than sufficient to fulfil the bacterial carbon requirement in the euphotic zone during this productive period. Changes in bacterial growth efficiencies (BGE, the ratio of bacterial production to bacterial carbon demand) were driven by changes in bacterial production rates increasing from 0.8 µm during the development of the spring bloom, followed 5 days later by a peak in bacterial production. In addition, the size fractionated respiration rates and high growth efficiencies suggest that free living bacteria are not the major producers of CO2 before, during and a few days after this shelf sea spring phytoplankton bloom.The Leverhulme Trust | Ref. RPG-2017-089UK Natural Environment Research Council (NERC) | Ref. NE/K00168X/1UK Natural Environment Research Council (NERC) | Ref. NE/ K001884/1UK Natural Environment Research Council (NERC) | Ref. NE/K002058/1UK Natural Environment Research Council (NERC) | Ref. NE/K001701/

Population screening for colorectal cancer means getting FIT:the past, present, and future of colorectal cancer screening using the fecal immunochemical test for hemoglobin (FIT)

Fecal immunochemical tests for hemoglobin (FIT) are changing the manner in which colorectal cancer (CRC) is screened. Although these tests are being performed worldwide, why is this test different from its predecessors? What evidence supports its adoption? How can this evidence best be used? This review addresses these questions and provides an understanding of FIT theory and practices to expedite international efforts to implement the use of FIT in CRC screening

A comprehensive understanding of carbon-carbon bond formation by alkyne migratory insertion into manganacycles

Migratory insertion (MI) is one of the most important processes underpinning the transition metal-catalysed formation of C-C and C-X bonds. In this work, a comprehensive model of MI is presented, based on the direct observation of the states involved in the coupling of alkynes with cyclometallated ligands, augmented with insight from computational chemistry. Time-resolved spectroscopy demonstrates that photolysis of complexes [Mn(C^N)(CO)4] (C^N = cyclometalated ligand) results in ultra-fast dissociation of a CO ligand. Performing the experiment in a toluene solution of an alkyne results in the initial formation of a solvent complex fac-[Mn(C^N)(toluene)(CO)3]. Solvent substitution gives an η2-alkyne complex fac-[Mn(C^N)(η2-R1C2R2)(CO)3] which undergoes MI of the unsaturated ligand into the Mn-C bond. These data allowed for the dependence of second order rate constants for solvent substitution and first order rate constants for C-C bond formation to be determined. A systematic investigation into the influence of the alkyne and C^N ligand on this process is reported. The experimental data enabled the development of a computational model for the MI reaction which demonstrated that a synergic interaction between the metal and the nascent C-C bond controls both the rate and regiochemical outcome of the reaction. The time-resolved spectroscopic method enabled the observation of a multi-step reaction occurring over 8 orders of magnitude in time, including the formation of solvent complexes, ligand substitution and two sequential C-C bond formation steps

Associations between high temperatures in pregnancy and risk of preterm birth, low birth weight, and stillbirths: systematic review and meta-analysis.

OBJECTIVE: To assess whether exposure to high temperatures in pregnancy is associated with increased risk for preterm birth, low birth weight, and stillbirth. DESIGN: Systematic review and random effects meta-analysis. DATA SOURCES: Medline and Web of Science searched up to September 2018, updated in August 2019. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Clinical studies on associations between high environmental temperatures, and preterm birth, birth weight, and stillbirths. RESULTS: 14 880 records and 175 full text articles were screened. 70 studies were included, set in 27 countries, seven of which were countries with low or middle income. In 40 of 47 studies, preterm births were more common at higher than lower temperatures. Exposures were classified as heatwaves, 1°C increments, and temperature threshold cutoff points. In random effects meta-analysis, odds of a preterm birth rose 1.05-fold (95% confidence interval 1.03 to 1.07) per 1°C increase in temperature and 1.16-fold (1.10 to 1.23) during heatwaves. Higher temperature was associated with reduced birth weight in 18 of 28 studies, with considerable statistical heterogeneity. Eight studies on stillbirths all showed associations between temperature and stillbirth, with stillbirths increasing 1.05-fold (1.01 to 1.08) per 1°C rise in temperature. Associations between temperature and outcomes were largest among women in lower socioeconomic groups and at age extremes. The multiple temperature metrics and lag analyses limited comparison between studies and settings. CONCLUSIONS: Although summary effect sizes are relatively small, heat exposures are common and the outcomes are important determinants of population health. Linkages between socioeconomic status and study outcomes suggest that risks might be largest in low and middle income countries. Temperature rises with global warming could have major implications for child health. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD 42019140136 and CRD 42018118113