35 research outputs found
A Distinct Layer of the Medulla Integrates Sky Compass Signals in the Brain of an Insect
Mass migration of desert locusts is a common phenomenon in North Africa and the Middle East but how these insects navigate is still poorly understood. Laboratory studies suggest that locusts are able to exploit the sky polarization pattern as a navigational cue. Like other insects locusts detect polarized light through a specialized dorsal rim area (DRA) of the eye. Polarization signals are transmitted through the optic lobe to the anterior optic tubercle (AOTu) and, finally, to the central complex in the brain. Whereas neurons of the AOTu integrate sky polarization and chromatic cues in a daytime dependent manner, the central complex holds a topographic representation of azimuthal directions suggesting a role as an internal sky compass. To understand further the integration of sky compass cues we studied polarization-sensitive (POL) neurons in the medulla that may be intercalated between DRA photoreceptors and AOTu neurons. Five types of POL-neuron were characterized and four of these in multiple recordings. All neurons had wide arborizations in medulla layer 4 and most, additionally, in the dorsal rim area of the medulla and in the accessory medulla, the presumed circadian clock. The neurons showed type-specific orientational tuning to zenithal polarized light and azimuth tuning to unpolarized green and UV light spots. In contrast to neurons of the AOTu, we found no evidence for color opponency and daytime dependent adjustment of sky compass signals. Therefore, medulla layer 4 is a distinct stage in the integration of sky compass signals that precedes the time-compensated integration of celestial cues in the AOTu
Selection and validation of reference genes for quantitative RT-PCR expression studies of the non-model crop Musa
Effect of donor nephrectomy time during circulatory-dead donor kidney retrieval on transplant graft failure
BACKGROUND: When the blood supply ceases in a deceased organ donor, ischaemic injury starts. Kidneys are cooled to reduce cellular metabolism and minimize ischaemic injury. This cooling is slow and kidneys are lukewarm during nephrectomy. Smaller single-centre studies have shown that prolonged donor nephrectomy time decreases early kidney transplant function, but the effect on long-term outcome has never been investigated in large multicentre cohort studies. METHODS: The relationship between donor nephrectomy time and death-censored graft survival was evaluated in recipients of single adult-to-adult, first-time deceased-donor kidneys transplanted in the Eurotransplant region between 2004 and 2013. RESULTS: A total of 13 914 recipients were included. Median donor nephrectomy time was 51 (i.q.r. 39-65) min. Kidneys donated after circulatory death had longer nephrectomy times than those from brain-dead donors: median 57 (43-78) versus 50 (39-64) min respectively (P < 0·001). Donor nephrectomy time was independently associated with graft loss when kidneys were donated after circulatory death: adjusted hazard ratio (HR) 1·05 (95 per cent c.i. 1·01 to 1·09) per 10-min increase (P = 0·026). The magnitude of this effect was comparable to the effect of each hour of additional cold ischaemia: HR 1·04 (1·01 to 1·07) per h (P = 0·004). For kidneys donated after brain death, there was no effect of nephrectomy time on graft survival: adjusted HR 1·01 (0·98 to 1·04) per 10 min (P = 0·464). CONCLUSION: Prolonged donor nephrectomy time impairs graft outcome in kidneys donated after circulatory death. Keeping this short, together with efficient cooling during nephrectomy, might improve outcome.status: publishe
De digitalisering voor iedereen!
De 4e industriële revolutie of ‘Industrie 4.0’ berust op een nieuwe manier om de productie te organiseren. De onderling verbonden technologieën en het internet der dingen vormen de spil van deze revolutie. De technologie stelt zich met andere woorden meer dan ooit ten dienste van de bouw- sector. Ze verdient dus zeker onze aandacht, al moet de technologische vooruitgang steeds nauwkeurig opgevolgd worden. Dit is precies de rol van het Technische Comité BIM & ICT.
BIM staat voor Building Information Model en maakt gebruik van een digi- taal model van het gebouw. Dit model bestaat niet meer uit lijnen, maar uit digitale objecten die een weergave zijn van de materialen en systemen die op de werf uitgevoerd zullen worden. Op die manier bekomt men een getrouw beeld van het werkelijke verloop van de uitvoeringsfase. ICT of Information and Communication Technologies slaat op zijn beurt op alle technologieën voor informatie-uitwisseling. Zowel BIM als ICT houden dus verband met datgene waar de 4e industriële revolutie om draait: het delen van informatie. Zodoende kunnen herhalingen, fouten en inefficiënties ver- meden worden en kan men beter anticiperen en plannen teneinde eventuele problemen op de werf te vermijden. Daarnaast zal men dankzij de digitali- sering binnenkort kunnen communiceren door middel van robots, drones of 3D-printers. ‘Industrie 4.0’ is immers ook een waaier van hulpmiddelen voor de ontwerpers, fabrikanten, beheerders, bouwers of verbouwers. De innovatie in de bouwsector gaat dus niet langer in stilte aan ons voorbij.
De 4e industriële revolutie stelt het WTCB niet alleen voor een uitdaging, maar biedt ook kansen. Zo kunnen de in de Technische Voorlichtingen geformuleerde aanbevelingen in het model ter beschikking gesteld worden van de gebruikers. Denken we hierbij maar even aan programma’s die waarschuwen wanneer de samenstelling van een wand niet overeenstemt met de aanbevelingen of wanneer de vooropgestelde uitvoeringstermijn te kort is om de toereikende droging van een voor een parket bestemde dekvloer veilig te stellen.
Het WTCB staat ten dienste van de hele bouwsector en streeft ernaar het concurrentievermogen van de bouwondernemingen en de kwaliteit van de bouwwerken te verbeteren. Dit is ook het oogmerk van ‘Industrie 4.0’. Wij wensen daarom een blijvende drijfveer te zijn in de ontwikkeling van deze technologieën, opdat alle partners hierbij gebaat zouden zijn. Zo bestaan er zowel voor de grote bedrijven als voor de ambachtsman een BIM en digitale hulpmiddelen op maat.
Deze WTCB-Contact heeft tot doel om u hiervan te overtuigen en u aan te moedigen om de stap te zetten. Er zit immers toekomst in voor uw bedrijf.no ISBN/ISSNstatus: publishe
The third sphere: Reconceptualising allyship in community-based participatory research praxis
Assessing the Complex Causes of Kidney Allograft Loss
BACKGROUND: Although graft loss is a primary endpoint in many studies in kidney transplantation and a broad spectrum of risk factors has been identified, the eventual causes of graft failure in individual cases remain ill studied. METHODS: We performed a single-center cohort study in 1000 renal allograft recipients, transplanted between March 2004 and February 2013. RESULTS: In total, 365 graft losses (36.5%) were identified, of which 211 (57.8%) were due to recipient death with a functioning graft and 154 (42.2%) to graft failure defined as return to dialysis or retransplantation. The main causes of recipient death were malignancy, infections, and cardiovascular disease. The main causes of graft failure were distinct for early failures, where structural issues and primary nonfunction prevailed, compared to later failures with a shift towards chronic injury. In contrast to the main focus of current research efforts, pure alloimmune causes accounted for only 17.5% of graft failures and only 7.4% of overall graft losses, although 72.7% of cases with chronic injury as presumed reason for graft failure had prior rejection episodes, potentially suggesting that alloimmune phenomena contributed to the chronic injury. CONCLUSIONS: In conclusion, this study provides better insight in the eventual causes of graft failure, and their relative contribution, highlighting the weight of nonimmune causes. Future efforts aimed to improve outcome after kidney transplantation should align with the relative weight and expected impact of targeting these causes.status: publishe
Septal cholinergic input to ca2 hippocampal region controls social novelty discrimination via nicotinic receptor-mediated disinhibition
Acetylcholine (ACh), released in the hippocampus from fibers originating in the medial septum/diagonal band of Broca (MSDB) complex, is crucial for learning and memory. The CA2 region of the hippocampus has received increasing attention in the context of social memory. However, the contribution of ACh to this process remains unclear. Here, we show that in mice, ACh controls social memory. Specifically, MSDB cholinergic neurons inhibition impairs social novelty discrimination, meaning the propensity of a mouse to interact with a novel rather than a familiar conspecific. This effect is mimicked by a selective antagonist of nicotinic AChRs delivered in CA2. Ex vivo recordings from hippocampal slices provide insight into the underlying mechanism, as activation of nAChRs by nicotine increases the excitatory drive to CA2 principal cells via disinhibition. In line with this observation, optogenetic activation of cholinergic neurons in MSDB increases the firing of CA2 principal cells in vivo. These results point to nAChRs as essential players in social novelty discrimination by controlling inhibition in the CA2 region
Behavioural and physiological mechanisms of polarized light sensitivity in birds
Polarized light (PL) sensitivity is relatively well studied in a large number of invertebrates and some fish species, but in most other vertebrate classes, including birds, the behavioural and physiological mechanism of PL sensitivity remains one of the big mysteries in sensory biology. Many organisms use the skylight polarization pattern as part of a sun compass for orientation, navigation and in spatial orientation tasks. In birds, the available evidence for an involvement of the skylight polarization pattern in sun-compass orientation is very weak. Instead, cue-conflict and cue-calibration experiments have shown that the skylight polarization pattern near the horizon at sunrise and sunset provides birds with a seasonally and latitudinally independent compass calibration reference. Despite convincing evidence that birds use PL cues for orientation, direct experimental evidence for PL sensitivity is still lacking. Avian double cones have been proposed as putative PL receptors, but detailed anatomical and physiological evidence will be needed to conclusively describe the avian PL receptor. Intriguing parallels between the functional and physiological properties of PL reception and light-dependent magnetoreception could point to a common receptor system