Central synapses release a resource-efficient amount of glutamate.

Why synapses release a certain amount of neurotransmitter is poorly understood. We combined patch-clamp electrophysiology with computer simulations to estimate how much glutamate is discharged at two distinct central synapses of the rat. We found that, regardless of some uncertainty over synaptic microenvironment, synapses generate the maximal current per released glutamate molecule while maximizing signal information content. Our result suggests that synapses operate on a principle of resource optimization

The Cow: Discovery of a Luminous, Hot, and Rapidly Evolving Transient

We present the ATLAS discovery and initial analysis of the first 18 days of the unusual transient event, ATLAS18qqn/AT2018cow. It is characterized by a high peak luminosity (~1.7 × 1044 erg s−1), rapidly evolving light curves (>5 mag rise to peak in ~3.5 days), and hot blackbody spectra, peaking at ~27,000 K that are relatively featureless and unchanging over the first two weeks. The bolometric light curve cannot be powered by radioactive decay under realistic assumptions. The detection of high-energy emission may suggest a central engine as the powering source. Using a magnetar model, we estimated an ejected mass of 0.1–0.4 M ${}_{\odot }$, which lies between that of low-energy core-collapse events and the kilonova, AT2017gfo. The spectra cooled rapidly from 27,000 to 15,000 K in just over two weeks but remained smooth and featureless. Broad and shallow emission lines appear after about 20 days, and we tentatively identify them as He i although they would be redshifted from their rest wavelengths. We rule out that there are any features in the spectra due to intermediate mass elements up to and including the Fe group. The presence of r-process elements cannot be ruled out. If these lines are due to He, then we suggest a low-mass star with residual He as a potential progenitor. Alternatively, models of magnetars formed in neutron star mergers, or accretion onto a central compact object, give plausible matches to the data

Interventional radiology virtual simulator for liver biopsy

Purpose Training in Interventional Radiology currently uses the apprenticeship model, where clinical and technical skills of invasive procedures are learnt during practice in patients. This apprenticeship training method is increasingly limited by regulatory restrictions on working hours, concerns over patient risk through trainees’ inexperience and the variable exposure to case mix and emergencies during training. To address this, we have developed a computer-based simulation of visceral needle puncture procedures. Methods A real-time framework has been built that includes: segmentation, physically based modelling, haptics rendering, pseudo-ultrasound generation and the concept of a physical mannequin. It is the result of a close collaboration between different universities, involving computer scientists, clinicians, clinical engineers and occupational psychologists. Results The technical implementation of the framework is a robust and real-time simulation environment combining a physical platform and an immersive computerized virtual environment. The face, content and construct validation have been previously assessed, showing the reliability and effectiveness of this framework, as well as its potential for teaching visceral needle puncture. Conclusion A simulator for ultrasound-guided liver biopsy has been developed. It includes functionalities and metrics extracted from cognitive task analysis. This framework can be useful during training, particularly given the known difficulties in gaining significant practice of core skills in patients

Expression analysis onto microarrays of randomly selected cDNA clones highlights HOXB13 as a marker of human prostate cancer

In a strategy aimed at identifying novel markers of human prostate cancer, we performed expression analysis using microarrays of clones randomly selected from a cDNA library prepared from the LNCaP prostate cancer cell line. Comparisons of expression profiles in primary human prostate cancer, adjacent normal prostate tissue, and a selection of other (nonprostate) normal human tissues, led to the identification of a set of clones that were judged as the best candidate markers of normal and/or malignant prostate tissue. DNA sequencing of the selected clones revealed that they included 10 genes that had previously been established as prostate markers: NKX3.1, KLK2, KLK3 (PSA), FOLH1 (PSMA), STEAP2, PSGR, PRAC, RDH11, Prostein and FASN. Following analysis of the expression patterns of all selected and sequenced genes through interrogation of SAGE databases, a further three genes from our clone set, HOXB13, SPON2 and NCAM2, emerged as additional candidate markers of human prostate cancer. Quantitative RT–PCR demonstrated the specificity of expression of HOXB13 in prostate tissue and revealed its ubiquitous expression in a series of 37 primary prostate cancers and 20 normal prostates. These results demonstrate the utility of this expression-microarray approach in hunting for new markers of individual human cancer types

Lighting during grow-out and Salmonella in broiler flocks

<p>Abstract</p> <p>Background</p> <p>Lighting is used during conventional broiler grow-out to modify bird behaviour to reach the goals of production and improve bird welfare. The protocols for lighting intensity vary. In a field study, we evaluated if the lighting practices impact the burden of <it>Salmonella </it>in broiler flocks.</p> <p>Methods</p> <p>Conventional grow-out flocks reared in the states of Alabama, Mississippi and Texas, USA in 2003 to 2006 were sampled 1 week before harvest (<it>n </it>= 58) and upon arrival for processing (<it>n </it>= 56) by collecting feathered carcass rinsate, crop and one cecum from each of 30 birds, and during processing by collecting rinsate of 30 carcasses at pre-chilling (<it>n </it>= 56) and post-chilling points (<it>n </it>= 54). Litter samples and drag swabs of litter were collected from the grow-out houses after bird harvest (<it>n </it>= 56). Lighting practices for these flocks were obtained with a questionnaire completed by the growers. Associations between the lighting practices and the burden of <it>Salmonella </it>in the flocks were tested while accounting for variation between the grow-out farms, their production complexes and companies.</p> <p>Results</p> <p>Longer relative duration of reduced lights during the grow-out period was associated with reduced detection of <it>Salmonella </it>on the exterior of birds 1 week before harvest and on the broiler carcasses at the post-chilling point of processing. In addition, starting reduced lights for ≥18 hours per day later in the grow-out period was associated with decreased detection of <it>Salmonella </it>on the exterior of broilers arriving for processing and in the post-harvest drag swabs of litter from the grow-out house.</p> <p>Conclusions</p> <p>The results of this field study show that lighting practices implemented during broiler rearing can impact the burden of <it>Salmonella </it>in the flock. The underlying mechanisms are likely to be interactive.</p

A biophysical model of endocannabinoid-mediated short term depression in hippocampal inhibition

Memories are believed to be represented in the synaptic pathways of vastly interconnected networks of neurons. The plasticity of synapses, that is, their strengthening and weakening depending on neuronal activity, is believed to be the basis of learning and establishing memories. An increasing number of studies indicate that endocannabinoids have a widespread action on brain function through modulation of synap–tic transmission and plasticity. Recent experimental studies have characterised the role of endocannabinoids in mediating both short- and long-term synaptic plasticity in various brain regions including the hippocampus, a brain region strongly associated with cognitive functions, such as learning and memory. Here, we present a biophysically plausible model of cannabinoid retrograde signalling at the synaptic level and investigate how this signalling mediates depolarisation induced suppression of inhibition (DSI), a prominent form of shortterm synaptic depression in inhibitory transmission in hippocampus. The model successfully captures many of the key characteristics of DSI in the hippocampus, as observed experimentally, with a minimal yet sufficient mathematical description of the major signalling molecules and cascades involved. More specifically, this model serves as a framework to test hypotheses on the factors determining the variability of DSI and investigate under which conditions it can be evoked. The model reveals the frequency and duration bands in which the post-synaptic cell can be sufficiently stimulated to elicit DSI. Moreover, the model provides key insights on how the state of the inhibitory cell modulates DSI according to its firing rate and relative timing to the post-synaptic activation. Thus, it provides concrete suggestions to further investigate experimentally how DSI modulates and is modulated by neuronal activity in the brain. Importantly, this model serves as a stepping stone for future deciphering of the role of endocannabinoids in synaptic transmission as a feedback mechanism both at synaptic and network level

Specific phobia predicts psychopathology in young women

Contains fulltext : 90255.pdf (publisher's version ) (Closed access)Although specific phobia is characterized by an early age at onset and by high rates of comorbidity, few studies have examined comorbid relationships prospectively. The present study investigated the association between specific phobia and the risk of a broad range of psychopathology among young women in the community. Data came from the Dresden Predictor Study in which 1,538 German women (18-25 years) completed a diagnostic interview at two time points. Women with specific phobia had a twofold increase in odds of developing any anxiety disorder, generalized anxiety disorder, depression, and any somatoform disorder during 17 months, compared to women without specific phobia. Except for depression, these associations persisted after adjustment for all comorbid mental disorders. Specific phobia thus appears to be a risk factor for a variety of problems. The result further underpins the necessity for early intervention for specific phobia to prevent later mental health problems

Assaying Total Carotenoids in Flours of Corn and Sweetpotato by Laser Photoacoustic Spectroscopy

This study describes the application of the laser photoacoustic spectroscopy (PAS) for quantification of total carotenoids (TC) in corn flours and sweetpotato flours. Overall, thirty-three different corn flours and nine sweetpotato flours were investigated. All PAS measurements were performed at room temperature using 488-nm argon laser radiation for excitation and mechanical modulation of 9 and 30 Hz. The measurements were repeated within a run and within several days or months. The UV–Vis spectrophotometry was used as the reference method. The concentration range that allows for the reliable analysis of TC spans a region from 1 to 40 mg kg−1 for corn flours and from 9 to 40 mg kg−1 for sweetpotato flours. In the case of sweetpotato flours, the quantification may extend even to 240 mg kg−1 TC. The estimated detection limit values for TC in corn and sweetpotato flours were 0.1 and 0.3 mg kg−1, respectively. The computed repeatability (n = 3–12) and intermediate precision (n = 6–28) RSD values at 9 and 30 Hz are comparable: 0.1–17.1% and 5.3–14.7% for corn flours as compared with 1.4–9.1% and 4.2–23.0% for sweetpotato flours. Our results show that PAS can be successfully used as a new analytical tool to simply and rapidly screen the flours for their nutritional potential based on the total carotenoid concentration