136 results on '"Zammit, Christian"'
Search Results
2. LITT for biopsy proven radiation necrosis: A qualitative systematic review
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Cuschieri, Andrea, Borg, Mariah, Levinskaia, Eliza, and Zammit, Christian
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- 2023
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3. Climate change impacts on erosion and suspended sediment loads in New Zealand
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Neverman, Andrew J., Donovan, Mitchell, Smith, Hugh G., Ausseil, Anne-Gaelle, and Zammit, Christian
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- 2023
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4. Closed loop deep brain stimulation: A systematic scoping review
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Cuschieri, Andrea, Borg, Nicole, and Zammit, Christian
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- 2022
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5. Intersection
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Zammit, Christian
- Published
- 2023
6. Sella turcica bridging: a systematic review
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Cuschieri, Andrea, Cuschieri, Sarah, and Zammit, Christian
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- 2022
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7. Moisture Transport during Large Snowfall Events in the New Zealand Southern Alps : The Role of Atmospheric Rivers
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Porhemmat, Rasool, Purdie, Heather, Zawar-Reza, Peyman, Zammit, Christian, and Kerr, Tim
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- 2021
8. Climate change adaptation through an integrative lens in Aotearoa New Zealand.
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Lawrence, Judy, Wreford, Anita, Blackett, Paula, Hall, David, Woodward, Alistair, Awatere, Shaun, Livingston, Mary E., Macinnis-Ng, Cate, Walker, Susan, Fountain, Joanna, Costello, Mark John, Ausseil, Anne-Gaelle E., Watt, Michael S., Dean, Sam M., Cradock-Henry, Nicholas A., Zammit, Christian, and Milfont, Taciano L.
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CLIMATE change adaptation ,GREENHOUSE gas mitigation ,PHYSIOLOGICAL adaptation - Abstract
Climate change is being felt across all human and natural systems in Aotearoa New Zealand and is projected to worsen this decade as impacts compound and cascade through natural system and sectoral dependencies. The effectiveness of adaptation is constrained by how fast greenhouse gas emissions are reduced globally, the pace of change, the frequency and progression of impacts, and the capacity of our natural, societal and political systems to respond. We explore how these systems and sectors interact with existing and projected climate change stressors by categorising climate change impacts (Trends and Events) and consequential thresholds (Thresholds), and by grouping systems and sectors by types (Typologies). This approach has identified commonalities and differences between the typologies which are illustrated with examples. Critical constraints and opportunities for adaptation have been identified to guide sector adaptation decision-making and for ongoing adaptation progress and effectiveness monitoring. Constraints are found across all sectors, and opportunities exist to address them through modelling and projections, monitoring frameworks, decision tools and measures, governance coordination and integration of the Māori worldview of the relationship between humans and nature. However, limits to adaptation exist and will increase over time unless all sectors and all nations urgently reduce their emissions. [ABSTRACT FROM AUTHOR]
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- 2024
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9. Perceptions of First-Year Medical Students towards Learning Anatomy Using Cadaveric Specimens through Peer Teaching
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Agius, Andee, Calleja, Neville, Camenzuli, Christian, Sultana, Roberta, Pullicino, Richard, Zammit, Christian, Calleja Agius, Jean, and Pomara, Cristoforo
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During the last decade, global interest in the multiple benefits of formal peer teaching has increased. This study aimed to explore the perceptions of first-year medical students towards the use of peer teaching to learn anatomy using cadaveric specimens. A descriptive, cross-sectional, retrospective survey was carried out. Data were collected using an online questionnaire which was administered to all medical students who were in their second year of their medical school curriculum and who had participated in sessions taught by their peers during their first year. Peer teaching was perceived as an effective method of learning anatomy by more than half of the participants. Analysis of mean responses revealed that the peer teachers created a positive, non-intimidating learning environment. Overall, participants gave positive feedback on their peer teachers. Six categories emerged from the responses given by participants as to why they would or would not recommend peer teaching. Ways of improvement as suggested by the respondents were also reported. Variables found to be significantly associated with the perceived benefits of the peer teaching program included sex differences, educational level and recommendations for peer teaching. This study brings to light the merits and demerits of peer teaching as viewed through the eyes of the peer learners. Peer teaching provides a sound platform for teaching and learning anatomy. Further discussions at higher levels are encouraged in order to explore the feasibility of introducing formal peer teaching in the medical curriculum.
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- 2018
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10. Letter to Editor re (2020 Sep;95(4):564–570)
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Zammit, Christian, Schembri Wismayer, Pierre, and Calleja Agius, Jean
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- 2022
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11. Functional Changes of Orexinergic Reaction to Psychoactive Substances
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Monda, Vincenzo, Salerno, Monica, Sessa, Francesco, Bernardini, Renato, Valenzano, Anna, Marsala, Gabriella, Zammit, Christian, Avola, Roberto, Carotenuto, Marco, Messina, Giovanni, and Messina, Antonietta
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- 2018
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12. Volatile organic compounds: instrumental and canine detections link an individual to the crime scene
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Filetti, Vera, Di Mizio, Giulio, Rendine, Marcello, Fortarezza, Palmira, Ricci, Pietrantonio, Pomara, Cristoforo, Messina, Giovanni, Riezzo, Irene, Zammit, Christian, Messina, Antonietta, Salerno, Monica, and Sessa, Francesco
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- 2019
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13. Parameterization of a National Groundwater Model for New Zealand.
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Griffiths, James, Yang, Jing, Woods, Ross, Zammit, Christian, Porhemmat, Rasool, Shankar, Ude, Rajanayaka, Channa, Ren, Jeffrey, and Howden, Nicholas
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Groundwater is a vital source of water for humanity, with up to 50% of global drinking water and 43% of irrigation water being derived from such sources. Quantitative assessment and accounting of groundwater is essential to ensure its sustainable management and use. TopNet-GW is a parsimonious groundwater model that was developed to provide groundwater simulation at national, regional, and local scales across New Zealand. At a national scale, the model can help local government authorities estimate groundwater resource reliability within and between regions. However, as many catchments are ungauged, the model cannot be calibrated to local conditions against observed data. This paper, therefore, describes a method to derive an a priori, reach-scale groundwater model parameter set from national-scale hydrogeological datasets. The parameter set includes coefficients of lateral (k
l ) and vertical (kr ) conductivity and effective aquifer storage (S). When the parameter set was used with the TopNet-GW model in the Wairau catchment in the Marlborough region (South Island, New Zealand), it produced a poor representation of peak river flows but a more accurate representation of low flows (overall NSE 0.64). The model performance decreased in the smaller Opawa catchment (NSE 0.39). It is concluded that the developed a priori parameter set can be used to provide national groundwater modeling capability in ungauged catchments but should be used with caution, and model performance would benefit greatly from local scale calibration. The parameter derivation method is repeatable globally if analogous hydrological and geological information is available and thus provides a basis for the parameterization of groundwater models in ungauged catchments. Future research will assess the spatial variability of parameter performance at a national scale in New Zealand. [ABSTRACT FROM AUTHOR]- Published
- 2023
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14. Real-time 3D UAV Path Planning in Dynamic Environments with Uncertainty.
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Zammit, Christian and van Kampen, Erik-Jan
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STOCHASTIC programming , *PARTIALLY observable Markov decision processes , *ROTORCRAFT , *DRONE aircraft , *REINFORCEMENT learning - Published
- 2023
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15. A hydroclimate-proxy model based on sedimentary facies in an annually laminated sequence from Lake Ohau, South Island, New Zealand
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Roop, Heidi A., Levy, Richard, Dunbar, Gavin B., Vandergoes, Marcus J., Howarth, Jamie, Fitzsimons, Sean, Moon, Heung Soo, Zammit, Christian, Ditchburn, Robert, Baisden, Troy, and Yoon, Ho Il
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- 2016
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16. Insurance Retreat in Residential Properties from Future Sea Level Rise in Aotearoa New Zealand
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Storey, Belinda, Owen, Sally, Zammit, Christian, and Noy, Ilan
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climate change ,Q54 ,SLR ,sea level rise ,ddc:330 ,retreat ,R38 ,insurance - Abstract
How will the increased frequency of coastal inundation events induced by sea level rise impact residential insurance premiums, and when would insurance contracts be withdrawn? We model the contribution of localised sea level rise to the increased frequency of coastal inundation events. Examining four Aotearoa New Zealand cities, we combine historical tide-gauge extremes with geo-located property data to estimate the annual expected loss from this hazard, for each property, to establish when insurance retreat is likely to occur. We find that as sea level rise changes the frequency of inundation events, 99% of properties currently within 1% AEP coastal inundation zones can expect at least partial insurance retreat within a decade (associated with less than 10cm of sea level rise). Our modelling predicts that full insurance retreat is likely within 20 – 25 years, with timing dependent on the tidal range in each location, and, more intuitively, on the property's elevation and distance from the coast.
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- 2022
17. Simulating the Hydrologic Response to Climate Change in Three New Zealand Headwater Basins Using CMIP6 Datasets.
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Risley, John C. and Zammit, Christian
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CLIMATE sensitivity , *CLIMATE change , *ATMOSPHERIC temperature , *HYDROLOGIC models , *DOWNSCALING (Climatology) - Abstract
Air temperature and precipitation outputs from 10 CMIP6 GCMs were input to the Precipitation-Runoff Modeling System hydrologic model to evaluate water and energy responses in three headwater basins to projected climate change over the twenty-first century. The headwater basins (398–801 km2) are located within the Mataura River basin in the South Island of New Zealand. CMIP6 datasets included two emission scenarios [shared socioeconomic pathways (SSPs) SSP2-4.5 and SSP5-8.5]. Half of the 10 GCMs selected in the study have equilibrium climate sensitivity (ECS) values above 4.5°C, which has been considered the upper end of equilibrium climate sensitivity. Modeling results included increased annual air temperature, evapotranspiration, and precipitation by the end of the twenty-first century for both SSP emissions scenarios, both high- and low-ECS GCMs, and all three headwater basins. Monthly precipitation and evapotranspiration totals also increased for all or most months. Monthly streamflow changes generally corresponded with monthly precipitation changes. Snowpack decreased significantly in depth and seasonal duration in all basins. However, streamflow increased for all SSP and ECS groups and basins because increased precipitation was consistently greater than increased evapotranspiration losses. Sources of uncertainty include the GCMs, climate sensitivity, downscaling, bias adjustment, emission scenarios, and the hydrologic model. Simulated hydrologic responses based on climate data from GCMs with ECS values of greater than 4.5°C could be less plausible since previous studies have suggested true ECS ranges from 1.5° to 4.5°C. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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18. Augmented reality for teaching anatomy.
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Zammit, Christian, Calleja‐Agius, Jean, and Azzopardi, Ernest
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- 2022
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19. New Trends in Immunohistochemical Methods to Estimate the Time since Death: A Review.
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Salerno, Monica, Cocimano, Giuseppe, Roccuzzo, Salvatore, Russo, Ilenia, Piombino-Mascali, Dario, Márquez-Grant, Nicholas, Zammit, Christian, Esposito, Massimiliano, and Sessa, Francesco
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TIME of death ,VITREOUS humor ,TECHNOLOGICAL innovations ,MOLECULAR biology ,FORENSIC sciences - Abstract
The identification of a reliable and accurate post-mortem interval (PMI) is a major challenge in the field of forensic sciences and criminal investigation. Several laboratory techniques have recently been developed that offer a better contribution to the estimation of PMI, in addition to the traditional physical or physico-chemical (body cooling, lividity, radiocarbon dating, rigor mortis), chemical (autolysis), microbiological (putrefaction), entomological, as well as botanical parameters. Molecular biology (degradation pattern of macromolecules such as proteins, DNA, RNA), biochemical analysis of biological fluids (such as blood, cerebrospinal fluid, and vitreous humor), and immunohistochemistry are some of the most recent technological innovations. A systematic review of the literature was performed with the aim of presenting an up-to-date overview on the correlation between the immunohistochemical (IHC) expression of specific antigenic markers at different PMIs. The systematic review was performed according to PRISMA guidelines. Scopus and PubMed were used as search engines from January 1, 1998 to March 1, 2022 to evaluate the effectiveness of immunohistochemistry in estimating PMI. The following keywords were used: (immunohistochemical) OR (immunohistochemistry) AND (time since death) OR (post-mortem interval) OR (PMI). A total of 6571 articles were collected. Ultimately, 16 studies were included in this review. The results of this systematic review highlighted that IHC techniques, in association with traditional methods, add, in Bayesian terms, additional information to define a more accurate time of death and PMI. However, current IHC results are numerically limited and more data and studies are desirable in the near future. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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20. Oligodendrocyte Pathophysiology and Treatment Strategies in Cerebral Ischemia
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Mifsud, Gabriella, Zammit, Christian, Muscat, Richard, Di Giovanni, Giuseppe, and Valentino, Mario
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- 2014
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21. Editorial: Rising stars in cellular neuropathology 2022.
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Zammit, Christian, Lian, Jiamei, and Valentino, Mario
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NEUROLOGICAL disorders ,PHOTORECEPTORS ,CORPUS callosum - Abstract
This document is an editorial published in Frontiers in Cellular Neuroscience in 2024. It discusses a research topic on rising stars in cellular neuropathology in 2022. The editorial highlights several research articles that shed light on various aspects of cellular neuropathology, including degenerative cervical myelopathy, aging markers in human induced dorsal forebrain precursor cells, the role of a-synuclein in Parkinson's disease, calcium signaling in glial excitability, and the effects of creatine supplementation on the fetal sheep brain. The editorial emphasizes the complexity of neuropathological conditions and the need for multidisciplinary approaches in treatment options. [Extracted from the article]
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- 2024
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22. Central axons preparing to myelinate are highly sensitivity to ischemic injury
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Alix, James J. P., Zammit, Christian, Riddle, Art, Meshul, Charles K., Back, Stephen A., Valentino, Mario, and Fern, Robert
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- 2012
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23. Comparison Between A* and RRT Algorithms for 3D UAV Path Planning.
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Zammit, Christian and van Kampen, Erik-Jan
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FLIGHT planning (Aeronautics) , *ALGORITHMS , *EVOLUTIONARY algorithms - Published
- 2022
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24. Brain Disease Mechanisms - Editor’s picks 2021 : vesicular glutamate release from central axons contributes to myelin damage
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Doyle, Sean, Bloch Hansen, Daniel, Vella, Jasmine, Bond, Peter, Harper, Glenn, Zammit, Christian, Valentino, Mario, and Fern, Robert
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Myelin sheath ,nervous system ,Myelin sheath -- Diseases ,Cerebrovascular disease - Abstract
The axon myelin sheath is prone to injury associated with N-methyl-D-aspartate (NMDA)- type glutamate receptor activation but the source of glutamate in this context is unknown. Myelin damage results in permanent action potential loss and severe functional deficit in the white matter of the CNS, for example in ischemic stroke. Here, we show that in rats and mice, ischemic conditions trigger activation of myelinic NMDA receptors incorporating GluN2C/D subunits following release of axonal vesicular glutamate into the peri-axonal space under the myelin sheath. Glial sources of glutamate such as reverse transport did not contribute significantly to this phenomenon. We demonstrate selective myelin uptake and retention of a GluN2C/D NMDA receptor negative allosteric modulator that shields myelin from ischemic injury. The findings potentially support a rational approach toward a low-impact prophylactic therapy to protect patients at risk of stroke and other forms of excitotoxic injury., peer-reviewed
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- 2018
25. L-lactate reduces ischemic white matter injury and modulates HCA1 oligodendrocyte expression in an in vivo mouse model of focal ischemia
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Valentino, Mario, Vella, J., Zammit, R., Zammit, Christian, and 10th Malta Medical School Conference
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Oligodendroglia ,White matter ,Axons -- Diseases ,Glucose -- Metabolism ,Transient ischemic attack ,Metabolic syndrome ,Brain -- Research - Abstract
L-lactate is a metabolite that is oxidized preferentially to glucose under conditions of high metabolic stress. The discovery and localization of the lactate receptor HCA1 in various brain regions suggests that lactate is additionally an important signaling molecule in the brain. Lactate is neuroprotective in various ischemia paradigms, reduces axonal injury in vitro and is avidly utilized by oligodendrocytes (OLs). The protective potential of L-lactate to reduce white matter (WM) injury in a mouse stroke model was investigated., N/A
- Published
- 2018
26. Elevated of nitric oxide during hypoglycemia cause structural and functional injury to callosal white matter axons in the rodent brain
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Zammit, Christian, Vella, J., Zammit, R., Borg, Daniel, Valentino, Mario, and 10th Malta Medical School Conference
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White matter ,Axons -- Diseases ,Glucose -- Metabolism ,Nitric oxide -- Research ,Hypoglycemia ,Brain -- Research - Abstract
Nitric oxide (NO) is a free radical that can act both as a signalling molecule and a neurotoxin. Previous literature suggest that it is involved in multiple brain pathologies. The main aim of this study was to investigate the role of NO in conduction block and structural axonal injury during and following glucose deprivation (GD)., N/A
- Published
- 2018
27. Land-use modelling in New Zealand: current practice and future needs
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Hendy, Jo, Ausseil, Anne-Gaelle, Bain, Isaac, Blanc, Elodie, Fleming, David, Gibbs, Joel, Hall, Alistar, Herzig, Alexander, Kavanagh, Patrick, Kerr, Suzi, Leining, Catherine, Leroy, Laetitia, Lou, Edmund, Monge, Juan, Reisinger, Andy, Risk, Jim, Soliman, Tarek, Stroombergen, Adolf, Timar, Levente, Van Der Weerdan, Tomy, White, Dominic, and Zammit, Christian
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modelling ,policy analysis ,data management ,Land-use ,Land Economics/Use - Abstract
New Zealand faces the challenge of using our land in ways that are not only resilient to future pressures and sustain our rural communities but also enhance our natural environment. For the public and private sectors to make robust land-use decisions under uncertainty, high-quality modelling tools and data are essential. The drivers of land-use decisions are complex and models provide a structured methodology for investigating these. While New Zealand is fortunate to have a range of different modelling tools, these have historically been used in a sporadic and ad hoc way, and underlying datasets are deficient in some areas. As the foundation for more strategic development of New Zealand’s modelling capability, this paper profiles the main land-sector and farm- and production-related models and datasets currently applied in New Zealand. It also explores priority policy areas where modelling is needed, such as achieving emission reduction targets; managing freshwater, biodiversity and soil quality; and understanding the distributional impacts of policy options as well as climate change. New Zealand’s modelling capability could be strengthened by collecting and sharing land-use data more effectively; building understanding of underlying relationships informed by primary research; creating more collaborative and transparent processes for applying common datasets, scenarios and assumptions, and conducting peer review; and conducting more integrated modelling across environmental issues. These improvements will require strategic policies and processes for refining model development, providing increased, predictable and sustained funding for modelling activity and underlying data collection and primary research, and strengthening networks across modellers inside and outside of government.
- Published
- 2018
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28. The influence of atmospheric circulation patterns during large snowfall events in New Zealand's Southern Alps.
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Porhemmat, Rasool, Purdie, Heather, Zawar‐Reza, Peyman, Zammit, Christian, and Kerr, Tim
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ATMOSPHERIC circulation ,AUTOMATIC meteorological stations ,GEOPOTENTIAL height ,SNOW accumulation ,AIR flow - Abstract
Large snowfall events contribute significantly to total annual snow accumulation across the maritime Southern Alps. However, the knowledge about atmospheric circulation patterns associated with large snowfall events over the New Zealand Southern Alps is very limited. Daily snow observation data from three automatic weather stations and ERA‐Interim reanalysis data were used to investigate the relationship between atmospheric forcing and large snowfall events across the Southern Alps. To do so, analysis of composite anomaly maps during large snowfall events were carried out to identify the common features of the days with heavy snow accumulation. Large snowfall across the Southern Alps are mainly associated with strong negative anomalies of sea level pressure (SLP) located over the southwest of New Zealand's South Island. These conditions are concurrent with negative anomalies of geopotential heights at 500 (Z500) located in the centre of low‐pressure systems. However, over New Zealand, days leading to large snowfall events experience positive anomalies of Z500 showing a relatively warm environment during such events in the maritime Southern Alps. Positive anomalies of low‐tropospheric temperatures (850 and 1,000 hPa) over the Tasman Sea and across the Southern Alps, strong values of integrated vapour transport (IVT) as well as high frequency of local synoptic patterns associated with troughing regimes (~78%) during large snowfall events provide more evidence of the important contribution of warm air flows. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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29. Climate Change Impacts and Implications for New Zealand to 2100 Synthesis Report: RA2 Uplands Case Study Upper Waitaki Catchment
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Rutledge, Daniel T, W T Baisden, Cradock-Henry, Nicholas, Keller, Elizabeth, Mason, Norman, Mullan, Brett, Overton, Jacob Mcc, Palmer, David, Sood, Abha, Stuart, Stephen, Tait, Andrew, Timar, Levente, Vetrova, Varvara, and Zammit, Christian
- Published
- 2017
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30. Targeted real time imaging of clot formation and the study of astrocyte injury during ischemia
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Valentino, Mario, Zammit, Robert, Zammit, Christian, Vella, Jasmine, Muscat, Richard, and The Brain in Focus : New Approaches to Imaging Neurons and Neuron Circuits
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Cerebral ischemia -- Diagnosis ,Astrocytes ,Neurovascular diseases -- Diagnosis ,Vascular dementia - Abstract
Astrocytes are the predominant glial-cell type of the neurovascular unit but little is known about their functional impact during ischemia. We describe the use of a modified photothrombotic technique employing a tightly focused 532nm green laser to optically excite the circulating photosensitizer rose bengal whilst visualization in real time clot formation and astrocyte injury under two-photon microscopy (2-PTM). Targeted vascular occlusions in small vessels of the brain is an important technique to study the microscopic basis of cerebral ischemia and vascular dementia. Using 2-PTM of green fluorescent protein-labeled astrocytes (GFAP-GFP) and 10-kDa Cascade Blue dextran to label the vasculature, we explore the alteration of the spatial relationship between cortical microcirculation and astrocytic structure in vivo during ischemia. This 2-PTM method allows extremely high spatial and temporal resolution for studying pathological mechanisms that underlie ischemic injury, including abnormal changes in cell signaling and structure, vascular dysfunction, and inflammation. This method ensures that instances of spontaneous clot dissolution and recanalization do not precipitate and confirms that a stable clot is formed and maintained throughout the observation period. We aim to identify the cellular basis of cerebrovascular dysregulation in transgenic animal models of neurological disease to identify molecular targets for the pharmacotherapy of these pathological pathways. By using this technique we could follow in real-time clot formation via a conventional scanner. Tornado bleaching generated a clot via a SIM scanner that was integrated in the light path. To block tissue autofluoresence and reflected light from the green laser, the light path was blocked by a 420-465nm filter that only permitted the blue emission of the intravenous injected cascade blue dextran used to label the plasma. Unlike other methods this technique allows real-time imaging of clot formation and permits the visualization of the green clot thus formed after intravenous loading of rhodamine 6G (0.3mg/kg in 300µL PBS) by switching back to the green channel. Two photon laser scanning fluorescence microscopy permitted the observation of changes in blood flow, blood redistribution after clot formation, platelet aggregation and the loss of integrity of neighbouring astrocytes through a cranial window in GFP-GFAP-expressing mice after targeted occlusion., N/A
- Published
- 2016
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31. A laser speckle contrast imaging system to study blood flow dynamics in the rodent brain
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Zammit, Robert, Vella, Jasmine, Zammit, Christian, Muscat, Richard, Valentino, Mario, and IX Malta Medical School Conference
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genetic structures ,Blood-vessels -- Physiology ,Animal experimentation ,Blood flow - Abstract
Optical imaging modalities have become increasingly prevalent in biomedical research for discerning functional and anatomical information. Laser Speckle Contrast Imaging (LSCI) is a non-invasive full-field optical imaging technique that gives a 2-D microcirculatory surface flow map within live tissue. LSCI is based on the grainy image produced by a laser light illuminating an object, known as a speckle pattern. The visual appearance of the speckle pattern produced by objects showing some kind of activity, such as flowing red blood cells (RBCs) is called a dynamic speckle. LSCI makes use of statistical analysis of the dynamic speckle pattern which is modulated by the speed information of the RBCs. The main setup of a LSCI consists of a 632 nm red laser, an optical imaging system and a CCD camera connected to a PC. LSCI is mainly used in pre-clinical studies by neuroscientists for CBF dynamics and in clinical examinations for blood perfusion imaging of the retina and the skin, for example during examination of burns., N/A
- Published
- 2015
32. Assessment of neuronal and glial injury in a rodent model of focal ischemia
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Vella, Jasmine, Zammit, Robert, Zammit, Christian, Muscat, Richard, Valentino, Mario, and IX Malta Medical School Conference
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Cerebrovascular disease -- Animal models ,Cerebral ischemia -- Diagnosis ,Neurovascular diseases -- Diagnosis ,cardiovascular diseases - Abstract
Human stroke affects equivalent volumes of gray and white matter. Traditionally, focus on assessment of ischemic injury in experimental models was dominated by histological assessment of neuronal viability and cell counts. However evidence has demonstrated the functional, behavioral and long-term impact of white matter lesions in stroke and therefore, a much needed effort to address the integrity of both gray and white matter lesions is important in devising strategies to protect the brain as a whole. Focal cerebral ischemia models simulating human stroke are indispensable in investigating cerebral gray and white matter injury. The intraluminal filament mouse middle cerebral artery occlusion (MCAO) model mimics one of the commonest causes of stroke in humans1 and is one of the most frequently used models in experimental stroke research. We adapt a mouse stroke model to study the pathological changes in the evolution of an infarct in both gray and white matter regions., N/A
- Published
- 2015
33. Functional electrophysiological assessment from optic nerve and callosal slice in mice to study white matter injury
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Zammit, Christian, Vella, Jasmine, Zammit, Robert, Muscat, Richard, Valentino, Mario, and IX Malta Medical School Conference
- Subjects
Glucose ,Electrophysiology -- Research ,Axons -- Physiology ,Optic nerve -- Wounds and injuries ,Glutamic acid - Abstract
This conference paper deals with comparing a number of records. Such records are the compound action potential recordings, the parameters used for recording, the structural vs functional analysis of axonal integrity following 15, 30 and 45 mins of glucose deprivation and the vulnerability of BRAIN SLICE vs OPTIC NERVE axons following 45 mins of Glucose Deprivation., N/A
- Published
- 2015
34. High-Fat Diet Induces Neuroinflammation and Mitochondrial Impairment in Mice Cerebral Cortex and Synaptic Fraction.
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Cavaliere, Gina, Trinchese, Giovanna, Penna, Eduardo, Cimmino, Fabiano, Pirozzi, Claudio, Lama, Adriano, Annunziata, Chiara, Catapano, Angela, Mattace Raso, Giuseppina, Meli, Rosaria, Monda, Marcellino, Messina, Giovanni, Zammit, Christian, Crispino, Marianna, and Mollica, Maria Pina
- Subjects
CEREBRAL cortex ,HIGH-fat diet ,SYNAPSES ,INFLAMMATION ,PLANT mitochondria ,BRAIN-derived neurotrophic factor ,NEUROPLASTICITY - Abstract
Brain mitochondrial dysfunction is involved in the development of neurological and neurodegenerative diseases. Mitochondria specifically located at synapses play a key role in providing energy to support synaptic functions and plasticity, thus their defects may lead to synaptic failure, which is a common hallmark of neurodegenerative diseases. High-Fat Diet (HFD) consumption increases brain oxidative stress and impairs brain mitochondrial functions, although the underlying mechanisms are not completely understood. The aim of our study is to analyze neuroinflammation and mitochondrial dysfunctions in brain cortex and synaptosomal fraction isolated from a mouse model of diet-induced obesity. Male C57Bl/6 mice were divided into two groups fed a standard diet or HFD for 18 weeks. At the end of the treatment, inflammation (detected by ELISA), antioxidant state (measured by enzymatic activity), mitochondrial functions and efficiency (detected by oxidative capacity and Seahorse analysis), and brain-derived neurotrophic factor (BDNF) pathway (analyzed by western blot) were determined in brain cortex and synaptosomal fraction. In HFD animals, we observed an increase in inflammatory parameters and oxidative stress and a decrease in mitochondrial oxidative capacity both in the brain cortex and synaptosomal fraction. These alterations parallel with modulation of BDNF, a brain key signaling molecule that is linking synaptic plasticity and energy metabolism. Neuroinflammation HFD-dependent negatively affects BDNF pathway and mitochondrial activity in the brain cortex. The effect is even more pronounced in the synaptic region, where the impaired energy supply may have a negative impact on neuronal plasticity. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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35. National classification of surface–groundwater interaction using random forest machine learning technique.
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Yang, Jing, Griffiths, James, and Zammit, Christian
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MACHINE learning ,RIPARIAN areas ,STREAMFLOW ,WATER supply ,LAND use - Abstract
Characterization of surface–groundwater interaction is an increasingly useful skill for riverine ecologists and water resource managers interested in the dynamics of water, nutrient, and micro‐organism exchange at the reach scale, as it can be used to better represent point‐scale processes within larger catchment‐scale models. This study describes a method for predicting the nature of reach‐scale surface–groundwater interaction, using the random forest (RF) machine learning technique with national‐scale geology, hydrology, and land use data. Observed stream flow depletion and accretion surveys from riparian areas and spring‐line flow accretion surveys were also used. The RF model allowed prediction of observed losing and gaining reaches with a high prediction accuracy ("out‐of‐bag" error < 10%). The performance of the model, however, was found to be dependent on the geographic administrative region. The model was also found to be sensitive to slope, distance to headwater, distance to coast, and underlying geological characteristics. When applied in New Zealand, this approach yielded a realistic conceptual representation of national surface–groundwater dynamics that are subsequently being used to inform a national‐scale hydrological model. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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36. A BRIEF DISSECTION'S GUIDE TO NORMAL MEDIASTINAL ANATOMY.
- Author
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Cipolla, Fabiana, Fazio, Benedetto, Polisano, Valentina, Sole, Francesca, Spataro, Benedetto, Venezia, Alfonso, Gammazza, Antonella Marino, Saguto, Dario, Pitruzzella, Alessandro, Mazzola, Margherita, Guarrera, Adele, Nobile, Serena, Gagliardo, Carola, Piccolo, Chiara Lo, Zammit, Christian, Porrello, Calogero, Tomasello, Giovanni, and Carini, Francesco
- Subjects
ANATOMY ,ANATOMY education ,COLLEGE students ,DEAD ,ABILITY grouping (Education) - Abstract
The purpose of this article is to show the mediastinal dissection method used during the stage performed by a group of students from the University of Palermo that, during the summer of 2017, had the opportunity to spend a period of 4 weeks at the Department of Anatomy of the University of Malta. The students were guided to practice dissection of some corpses to study various mediastinal organs. This experience permitted to the students to verify practically what they lernt in the books, and represented a unique opportunity for them to perform practice with cadavers, that is actually very difficult to do in Italian universities. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
37. The spectrum of Ischemia-induced white matter injury varies with age
- Author
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Zammit, Christian, Muscat, Richard, and Valentino, Mario
- Subjects
Cerebravascular disease ,cardiovascular diseases ,Cerebral ischemia - Abstract
Stroke is a neurological condition that targets the whole range of the human population, from the pre-term infant to the elderly and is a major cause of death worldwide (Ingall 2004). During its lifespan, the brain's vulnerability to hypoxia-ischemia varies. Term infants who suffer this insult usually exhibit widespread neuronal injury in the cerebral cortex with a stroke-like distribution of damage (Deng 2008), whereas in pre-term infants immature oligodendrocytes and subplate neurons below the neocortex are most vulnerable and result in Periventricular Leukomalacia (PVL) (Back et al. 2007; McQuillen et al. 2005). The incidence of stroke decreases in young adulthood, but peaks again in the elderly. Moreover, the underlying pathological mechanisms that occur following ischemia are different at each stage. Experimental stroke research on stroke has traditionally focused on grey matter injury, but recent evidence indicates that white matter injury is a critical part of its pathophysiology. In this debilitating condition the mechanisms of ischemia-induced damage differ with age and all cellular components of white matter (axons, oligodendrocytes and astrocytes) are affected. This review paper focuses on the relative vulnerability to ischemia of white matter during the course of development and on our recent findings of how individual cellular components are affected during each stage., peer-reviewed
- Published
- 2013
38. Adiponectin and Orexin-A as a Potential Immunity Link Between Adipose Tissue and Central Nervous System.
- Author
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Polito, Rita, Nigro, Ersilia, Messina, Antonietta, Monaco, Maria L., Monda, Vincenzo, Scudiero, Olga, Cibelli, Giuseppe, Valenzano, Anna, Picciocchi, Elisabetta, Zammit, Christian, Pisanelli, Daniela, Monda, Marcellino, Cincione, Ivan R., Daniele, Aurora, and Messina, Giovanni
- Subjects
ADIPONECTIN ,ADIPOSE tissues ,CENTRAL nervous system ,IMMUNOLOGIC diseases ,DISEASE progression ,ADIPOKINES - Abstract
Adipose tissue (AT) is strongly associated with development and progression of immune disorders through adipokines secretion, such as adiponectin. This protein has beneficial energetic properties and is involved in inflammation and immunity processes. Three oligomers of circulating adiponectin with different molecular weight are described: High (HMW), Medium (MMW), and Low (LMW). The HMW is the most biologically active oligomers. On binding to its receptors AdipoR1, AdipoR2, and T-cadherin, adiponectin acts on both innate and acquired immunity. The suppression of NF-κB activation and pro-inflammatory cytokine expression in macrophages is mediated by AdipoR1. AdipoR2 mediates polarization of anti-inflammatory M2 macrophages T-cadherin is essential for the M2 macrophage proliferation. Furthermore, adiponectin reduces T cells responsiveness and B cells lymphopoiesis. The immune system is very sensitive to environmental changes and it is not only interconnected with AT but also with the central nervous system (CNS). Cytokines, which are mediators of the immune system, exercise control over mediators of the CNS. Microglia, which are immunity cells belonging to the macrophage family, are present within the CNS. The nervous system is also involved in immunity through the production of neuropeptides such as orexin-A/hypocretin-1. This neuropeptide is involved in metabolic disorders, inflammation and in the immune response. The relationship between adipokines, immunity, and the nervous system is validated by both the role of orexin-A on fat, food intake, and energy expenditure, as well as by role of adiponectin on the CNS. In this review, we focused on the functions of adiponectin and orexin-A as a potential immunity link between AT and CNS. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
39. Long Feeding High-Fat Diet Induces Hypothalamic Oxidative Stress and Inflammation, and Prolonged Hypothalamic AMPK Activation in Rat Animal Model.
- Author
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Cavaliere, Gina, Viggiano, Emanuela, Trinchese, Giovanna, De Filippo, Chiara, Messina, Antonietta, Monda, Vincenzo, Valenzano, Anna, Cincione, Raffaele I., Zammit, Christian, Cimmino, Fabiano, Catapano, Angela, Sessa, Francesco, Messina, Giovanni, Monda, Marcellino, Crispino, Marianna, and Mollica, Maria Pina
- Subjects
HYPOTHALAMUS ,OBESITY ,AGING ,OXIDATIVE stress ,KINASES ,INFLAMMATION - Abstract
Scope: The hypothalamus is a key brain region involved in the control of feeding and energy expenditure. Hypothalamic inflammation and oxidative stress are landmarks of both obesity and aging processes, although the molecular mechanisms are still unknown. Therefore, with the aim to understand the neurobiological mechanisms of energy homeostasis during aging, we evaluate the effects of long feeding high-fat diet (HFD) in rats, at different age, on modulation of hypothalamic molecular pathway, oxidative stress, and inflammation.Procedures: Male Wistar rats were divided into two groups: control group, receiving standard diet (CD), and treated group, receiving HFD. Both groups were treated with the appropriate diet for 1, 3, 6, 12, or 18 weeks. We investigated energy balance and body composition, as well as lipid profile, homeostatic model assessment index, and inflammatory state in serum. Furthermore, we also analyzed, at hypothalamic level, inflammation and oxidative stress, and adenosine monophosphate-dependent kinase (AMPK) and pAMPK expression levels.Results: Our data showed that aging and HFD induce increased energy intake and energy efficiency and decreased energy expenditure associated, at hypothalamic level, with inflammation and oxidative stress and activation of AMPK.Conclusion: Our results indicate that the age at which HFD feeding starts and the diet duration are critical in obesity development. The prolonged activation of hypothalamic AMPK may be related to the alterations in energy homeostasis. [ABSTRACT FROM AUTHOR]- Published
- 2018
- Full Text
- View/download PDF
40. Vesicular glutamate release from central axons contributes to myelin damage.
- Author
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Doyle, Sean, Hansen, Daniel Bloch, Vella, Jasmine, Bond, Peter, Harper, Glenn, Zammit, Christian, Valentino, Mario, and Fern, Robert
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GLUTAMIC acid ,AXONS ,MYELIN sheath ,GLUTAMATE receptors ,METHYL aspartate receptors - Abstract
The axon myelin sheath is prone to injury associated with N-methyl-D-aspartate (NMDA)- type glutamate receptor activation but the source of glutamate in this context is unknown. Myelin damage results in permanent action potential loss and severe functional deficit in the white matter of the CNS, for example in ischemic stroke. Here, we show that in rats and mice, ischemic conditions trigger activation of myelinic NMDA receptors incorporating GluN2C/D subunits following release of axonal vesicular glutamate into the peri-axonal space under the myelin sheath. Glial sources of glutamate such as reverse transport did not contribute significantly to this phenomenon. We demonstrate selective myelin uptake and retention of a GluN2C/D NMDA receptor negative allosteric modulator that shields myelin from ischemic injury. The findings potentially support a rational approach toward a low-impact prophylactic therapy to protect patients at risk of stroke and other forms of excitotoxic injury. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
41. Influence of Football on Physiological Cardiac Indexes in Professional and Young Athletes.
- Author
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Francavilla, Cristian V., Sessa, Francesco, Salerno, Monica, Albano, Giuseppe D., Villano, Ines, Messina, Giovanni, Triolo, Fabio, Todaro, Lorenzo, Ruberto, Maria, Marsala, Gabriella, Cascio, Orazio, Mollica, Maria P., Monda, Vincenzo, Cibelli, Giuseppe, Valenzano, Anna, Zammit, Christian, Monda, Marcellino, and Messina, Antonietta
- Subjects
FOOTBALL ,PHYSICAL training & conditioning ,PHYSICAL activity ,CARDIOPULMONARY fitness ,LEFT heart ventricle - Abstract
Background: After long-term intensive training, considerable morphological and functional heart changes occur in professional athletes. Such changes arise progressively and regress upon interruption of the physical activity. Morphological and functional alterations on heart are known as "Athlete's heart" condition. Objective: This study aims to compare echocardiographic parameters in two different groups of professional athletes. Furthermore, a prospective study is performed analyzing the echocardiographic changes occurring in 12 professional players in 3 years of follow-up. Materials and Methods: 78 football players were examined from July 2011 to May 2016 (40 enrolled in Group A and 38 in Group B). Twelve players of GROUP A were followed for 3 consecutive seasons. The general clinical examination, the cardiopulmonary evaluation, the ECG, the ergometer stress test, the spirometric examination and the standard cardiac eco color doppler test were recorded. Results: Left ventricle dimensions, left atrium dimensions, and interventricular septum dimensions were higher in A players than in B players. Moreover, following up 12 players for 3 years, a statistically significant increase of such values was observed. Discussion: In A players, higher dimensions of the left chambers and the interventricular septum were observed, compared to B players. No statistically significant difference was found regarding the ejection fraction. The 3 years follow-up showed a statistically significant increase of both left chambers and interventricular septum dimensions, particularly in the second and third year. Conclusions: These findings demonstrated that A players have higher echocardiographic parameters respect to B players. The results of this study support the scientific theory that long-term intensive training influences heart function, inducing "athlete's heart" with morphological adaptations. No significant echocardiographic variation within the examined sample was observed for different roles (goalkeeper, defender, midfielder, or attacker) or skills of individual players. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
42. Non-Rapid Eye Movement Sleep Parasomnias and Migraine: A Role of Orexinergic Projections.
- Author
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Messina, Antonietta, Bitetti, Ilaria, Precenzano, Francesco, Iacono, Diego, Messina, Giovanni, Roccella, Michele, Parisi, Lucia, Salerno, Margherita, Valenzano, Anna, Maltese, Agata, Salerno, Monica, Sessa, Francesco, Albano, Giuseppe Davide, Marotta, Rosa, Villano, Ines, Marsala, Gabriella, Zammit, Christian, Lavano, Francesco, Monda, Marcellino, and Cibelli, Giuseppe
- Subjects
SEROTONINERGIC mechanisms ,SLEEP-wake cycle ,MIGRAINE - Abstract
Introduction Sleep and migraine share a common pathophysiological substrate, although the underlying mechanisms are unknown. The serotonergic and orexinergic systems are both involved in the regulation of sleep/wake cycle, and numerous studies show that both are involved in the migraine etiopathogenesis. These two systems are anatomically and functionally interconnected. Our hypothesis is that in migraine a dysfunction of orexinergic projections on the median raphe (MR) nuclei, interfering with serotonergic regulation, may cause Non-Rapid Eye Movement parasomnias, such as somnambulism. Hypothesis/theory Acting on the serotonergic neurons of the raphe nuclei, the dysfunction of orexinergic neurons would lead to a higher release of serotonin. The activation of serotonergic receptors located on the walls of large cerebral vessels would lead to abnormal vasodilatation and consequently increase transmural pressure. This process could activate the trigeminal nerve terminals that innervate vascular walls. As a consequence, there is activation of sensory nerve endings at the level of hard vessels in the meninges, with release of pro-inflammatory peptides (e.g., substance P and CGRP). Within this hypothetical frame, the released serotonin could also interact with trigeminovascular afferents to activate and/or facilitate the release of the neuropeptide at the level of the trigeminal ganglion. The dysregulation of the physiological negative feedback of serotonin on the orexinergic neurons, in turn, would contribute to an alteration of the whole system, altering the sleep-wake cycle. Conclusion Serotonergic neurons of the MR nuclei receive an excitatory input from hypothalamic orexin/hypocretin neurons and reciprocally inhibit orexin/hypocretin neurons through the serotonin 1A receptor (or 5-HT1A receptor). Considering this complex system, if there is an alteration it may facilitate the pathophysiological mechanisms involved in the migraine, while it may produce at the same time an alteration of the sleep-wake rhythm, causing sleep disorders such as sleepwalking. Understanding the complex mechanisms underlying migraine and sleep disorders and how these mechanisms can interact with each other, it would be crucial to pave the way for new therapeutic strategies. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
43. A BRIEF ANATOMO-SURGICAL DISSECTION GUIDE TO HUMAN NECK: RESULTS OF THE COLLABORATION BETWEEN THE UNIVERSITY OF PALERMO AND THE UNIVERSITY OF MALTA.
- Author
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Carini, Francesco, Salerno, Monica, Mazzola, Margherita, Piccolo, Chiara Lo, Cavallo, Giorgia, Musso, Sofia, Gentile, Stefania, D'Accardo, Stefania, Mantia, Alessia La, Accardo, Agostino, Baldari, Benedetta, Besi, Livia, Scopetti, Matteo, Faleo, Matteo, Zammit, Christian, and Tomasello, Giovanni
- Abstract
The aim of this article is to show methods for dissection of the neck. In the summer of 2017 a group of students of the University of Palermo that have already passed the exam of Human Anatomy took a 4 weeks dissection course at the University of Malta. The students were provided with a dissection kit, video recording equipment and cameras for taking pictures. They dissected the skin, the subcutaneous tissue, the muscular bundles, the muscles, the vascular and nervous bundles, the nerves, the larynx, the trachea and the esophagus. This paper presents the results of the dissection course and a small and simple guide to young students and medical doctors who want to learn the bases of neck dissection. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
44. Targeted single blood vessel occlusion in rodent pial arteries to study astrocyticvascular dysfunction in a mini-stroke model
- Author
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Valentino, Mario, Zammit, Christian, Pierucci, Massimo, Gravino, G., Galea, Bernard, Di Giovanni, Giuseppe, Muscat, Richard, and 8th Malta Medical School Conference
- Subjects
Cerebrovascular disease -- Animal models ,Arteries -- Physiology ,Blood-vessels -- Physiology ,Vascular endothelium -- Physiology -- Congresses ,Rodents as laboratory animals - Abstract
The ability to form targeted vascular occlusions in small vessels of the brain is an important technique to study the microscopic basis of cerebral ischemia. We utilize a method that enables the targeted occlusion of any single blood vessel within the upper 350 μm of mouse neocortex to generate highly localized regions of ischemia by blocking capillary or surface arteries. This method makes use of linear optical absorption by a photosensitizer, transiently circulated in the bloodstream, to induce a clot in a surface or near-surface segment of a vessel after activation with a green 532nm continuous laser. Using two-photon microscopy of green fluorescent protein-labeled astrocytes (GFEC) and 70-kDa Texas Red dextranlabeled blood flow, we explore the alteration of the spatial relationship between cortical microcirculation and astrocytic endfeet structure in vivo during ischemia. This two-photon imaging method allows extremely high spatial and temporal resolution for studying pathological mechanisms that underlie ischemic injury, including abnormal changes in cell signaling and structure, vascular dysfunction, and inflammation. We aim to identify the cellular basis of cerebrovascular dysregulation in transgenic animal models of neurological disease and identify molecular targets for the pharmacotherapy of these pathological pathways., N/A
- Published
- 2012
45. Serotonin-dopamine interaction in nicotine addiction: focus on 5-ht2c receptors
- Author
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Esposito, Ennio, Di Matteo, Vincenzo, Pierucci, Massimo, Benigno, Arcangelo, Pessia, Mauro, Pitruzzella, Alessandro, Zammit, Christian, Valentino, Mario, Muscat, Richard, and Di Giovanni, Giuseppe
- Subjects
Nicotinic receptors -- Research -- Methodology ,Dopamine -- Antagonists ,Nicotine addiction ,nervous system ,Serotonin -- Antagonists - Abstract
Central dopaminergic systems play a critical role in the regulation of normal and abnormal behaviors. Recent evidence suggests that a dysfunction of dopamine (DA) and serotonin (5-HT) neurotransmitter systems contribute to various pathological conditions. Substantial evidence indicates that the mesolimbic pathway, particularly the DA cells innervating accumbal areas, is implicated in the reward value of both natural and drug reinforcers, such as sexual behavior or psychostimulants, respectively. Nicotine, the major psychoactive agent present in tobacco, acts as a potent addictive drug both in humans and laboratory animals. The locomotor activation and the reinforcing effects of nicotine may be related to its stimulatory effects on the mesolimbic dopaminergic function. Thus, it is now well established that nicotine can increase in vivo DA outflow in the nucleus accumbens and the corpus striatum. The stimulatory effect of nicotine on DA release most probably results from its ability to excite neuronal firing rate and to increase bursting activity of DA neurons within the substantia nigra pars compacta (SNc) and the ventral tegmental area (VTA), together with its facilitatory activity on DA terminal release in the corpus striatum and the nucleus accumbens. The neurochemical data are consistent with neuroanatomical findings showing the presence of nicotinic acetylcholine receptors (nAChRs) in the SNc, VTA, and in projection areas of the central dopaminergic system such as the corpus striatum and the nucleus accumbens. Several lines of evidence indicate that the reinforcing properties of drugs of abuse, including nicotine, can be affected by the serotonergic system which may act by modulating central dopaminergic function. In this paper, the effects of 5-HT2C receptors on DA function in relation to the neurobiological mechanisms underlying nicotine addiction will be reviewed, and the possible strategies with 5-HT2C agents for new pharmacological treatments of nicotine dependence will be examined., peer-reviewed
- Published
- 2012
46. Extreme sensitivity of myelinating optic nerve axons in a rodent model of perinatal ischemic injury
- Author
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Zammit, Christian, Valentino, Mario, Alix, James J. P., Riddle, Art, Meshul, Charles K., Back, Stephen A., Fern, Robert, and 8th Maltese Medical School Conference
- Subjects
Myelinated neurofibrils -- Diseases ,Axons -- Physiology ,Cerebral ischemia -- Diagnosis - Abstract
Cerebral white matter injury (WMI) is increasingly recognized as a common form of perinatal brain injury that predisposes to cerebral palsy as well as cognitive and learning disabilities. Despite the growing impact of WMI, it is unclear whether common cellular and molecular mechanisms define WMI pathogenesis in preterm and term neonates. Although numerous studies have defined a role for glial vulnerability in WMI, there has been limited study of the susceptibility of immature axons., peer-reviewed
- Published
- 2012
47. Dysfunction of voltage-gated K + Channels Kv1.1 in sciatic nerve causes spontaneous and stress-induced neuromuscular hyperexcitability
- Author
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Brunetti, Orazio, Imbrici, Paola, Botti, Fabio Massimo, Pettorossi, Vito Enrico, D’Adamo, Maria Cristina, Valentino, Mario, Zammit, Christian, Mora, Marina, Di Giovanni, Giuseppe, Muscat, Richard, and Pessia, Mauro
- Subjects
nervous system ,Cerebral ischemia -- Diagnosis ,Ataxia ,Sciatic nerve ,Potassium channels - Abstract
Episodic ataxia type 1 (EA1) is an autosomal dominant neurological disorder characterized by myokymia and attacks of ataxic gait precipitated by stress events. Several genetic mutations have been identified in the Shaker-like K+ channel Kv1.1 (KCNA1) of EA1 individuals, including the V408A which results in remarkable channel dysfunction. By inserting heterozygous V408A mutation in one Kv1.1 allele, a mouse model of EA1 has been generated (Kv1.1 V408A/+). Here, we hypothesized that dysfunction of Kv1.1 channels in sciatic nerve of Kv1.1V408A/+ ataxia mice leads to neuromuscular hyperexcitability and to abnormal susceptibility to different stressors. By using in vivo preparations of lateral gastrocnemius (LG) nerve–muscle from Kv1.1+/+ and Kv1.1V408A/+ mice, we show that the mutant animals exhibit spontaneous myokymic discharges consisting of repeated singlets, duplets or multiplets, despite sciatic nerve axotomy. Two-photon laser scanning microscopy from the sciatic nerve, ex vivo, revealed spontaneous Ca2+ signals that occurred abnormally only in preparations dissected from Kv1.1V408A/+ mice. The spontaneous bursting activity, as well as that evoked by motor nerve stimulation, was exacerbated by muscle fatigue, ischemia and low temperatures. These stressors also increased the amplitude of muscle compound action potential. Such abnormal neuromuscular transmission did not alter fiber type composition neuromuscular junction and vascularization of LG muscle analyzed by light and electron microscopy. These findings indicate that dysfunction of Kv1.1 channels results in sciatic nerve hyperexcitability and myokymia/neuromyotonia in Kv1.1V408A/+ ataxia mice. Moreover, this study sheds new light on the functional role played by K + channels segregated under the myelin sheath, which becomes crucial in certain situations of physiological stress., peer-reviewed
- Published
- 2012
48. Direct tactile manipulation of the flight plan in a modern aircraft cockpit
- Author
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Alapetite, Alexandre, Fogh, Rune, Zammit-Mangion, David, Zammit, Christian, Agius, Ian, Fabbri, Marco, Pregnolato, Marco, and Becouarn, Loïc
- Subjects
Interaction ,Tactile ,Usability ,Cockpit - Abstract
An original experimental approach has been chosen, with an incremental progression from a traditional physical cockpit, to a tactile flight simulator reproducing traditional controls, to a prototype navigation display with direct tactile functionality, first located in the traditional low position, then located in front of pilots in desktop-like setup. The main findings are that naive tactile implementations bring a performance penalty compared to similar physical interfaces, but tactile approaches have a number of assets that will counterbalance this fact.
- Published
- 2012
49. Role of Sex Hormones in the Control of Vegetative and Metabolic Functions of Middle-Aged Women.
- Author
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Monda, Vincenzo, Salerno, Monica, Fiorenzo, Moscatelli, Villano, Ines, Viggiano, Andrea, Sessa, Francesco, Triggiani, Antonio I., Cibelli, Giuseppe, Valenzano, Anna, Marsala, Gabriella, Zammit, Christian, Ruberto, Maria, Messina, Giovanni, Monda, Marcellino, De Luca, Vincenzo, and Messina, Antonietta
- Subjects
SEX hormones ,MIDDLE-aged women ,METABOLISM ,POSTMENOPAUSE ,OXIDATIVE stress ,HORMONE therapy for menopause ,HEALTH - Abstract
Aims: In women's life, menopause is characterized by significant physiological changes often associated with an increase in body mass and obesity-associated sicknesses. Numerous researches described interdependencies of estrogen deficiency, aging, and resting energy expenditure (REE) downfall in the obesity correlated with the menopause. The aim of this study was to determining whether healthy, obese menopausal women underwent HRT treatment, showed changes in their REE, autonomic asset, and assessment of oxidative stress in comparison with obese pre- and post-menopausal women. Methodology: In this study, we measured the body composition, the REE, the oxidative stress, the diet assimilation, and the autonomic nervous system activity in three groups: pre-menopause women (n = 50), post-menopause women following hormone-replacement therapy (HRT; n = 50), and post-menopause women not following HRT (n = 50). Results: In the group with HRT a significant increase of the sympathetic activity and REE was described. Finally this group showed a notable increment of oxidative stress compared with the others, and utilizing BIA instrument, the free fat mass was increased respect to the fat mass of obese women. Conclusion: The study highlights the importance of the HRT-related physiological changes that influence body weight in menopause women. This results are important because have a practical implications for prevention and/or treatment of the obesity. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
50. Primary Motor Cortex Excitability in Karate Athletes: A Transcranial Magnetic Stimulation Study.
- Author
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Monda, Vincenzo, Valenzano, Anna, Moscatelli, Fiorenzo, Salerno, Monica, Sessa, Francesco, Triggiani, Antonio I., Viggiano, Andrea, Capranica, Laura, Marsala, Gabriella, De Luca, Vincenzo, Cipolloni, Luigi, Ruberto, Maria, Precenzano, Francesco, Carotenuto, Marco, Zammit, Christian, Gelzo, Monica, Monda, Marcellino, Cibelli, Giuseppe, Messina, Giovanni, and Messina, Antonietta
- Subjects
TRANSCRANIAL magnetic stimulation ,EVOKED potentials (Electrophysiology) ,MARTIAL artists ,MOTOR cortex ,NEUROPLASTICITY - Abstract
Purpose: The mechanisms involved in the coordination of muscle activity are not completely known: to investigate adaptive changes in human motor cortex Transcranial magnetic stimulation (TMS) was often used. The sport models are frequently used to study how the training may affect the corticospinal system excitability: Karate represents a valuable sport model for this kind of investigations for its high levels of coordination required to athletes. This study was aimed at examining possible changes in the resting motor threshold (rMT) and in the corticospinal response in karate athletes, and at determining whether athletes are characterized by a specific value of rMT. Methods: We recruited 25 right-handed young karate athletes and 25 matched non-athletes. TMS was applied to primary motor cortex (M1). Motor evoked potential (MEP) were recorded by two electrodes placed above the first dorsal interosseous (FDI) muscle. We considered MEP latencies and amplitudes at rMT, 110% of rMT, and 120% of rMT. Results: The two groups were similar for age (p > 0.05), height (p > 0.05) and body mass (p > 0.05). The TMS had a 70-mm figure-of-eight coil and a maximum output of 2.2 T, placed over the left motor cortex. During the stimulation, a mechanical arm kept the coil tangential to the scalp, with the handle at 45° respect to the midline. The SofTaxic navigator system (E.M.S. Italy, www.emsmedical.net) was used in order to correctly identifying and repeating the stimulation for every subject. Compared to non-athletes, athletes showed a lower resting motor threshold (p < 0.001). Furthermore, athletes had a lower MEP latency (p < 0.001) and a higher MEP amplitude (p < 0.001) compared to non-athletes. Moreover, a ROC curve for rMT was found significant (area: 0.907; sensitivity 84%, specificity 76%). Conclusions: As the main finding, the present study showed significant differences in cortical excitability between athletes and non-athletes. The training can improve cortical excitability inducing athletes' modifications, as demonstrated in rMT and MEP values. These finding support the hypothesis that the sport practice determines specific brain organizations in relationship with the sport challenges. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
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