775 research outputs found
Long term geological record of a global deep subsurface microbial habitat in sand injection complexes
Peer reviewedPublisher PD
Vaccines against toxoplasma gondii : challenges and opportunities
Development of vaccines against Toxoplasma gondii infection in humans is of high priority, given the high burden of disease in some areas of the world like South America, and the lack of effective drugs with few adverse effects. Rodent models have been used in research on vaccines against T. gondii over the past decades. However, regardless of the vaccine construct, the vaccines have not been able to induce protective immunity when the organism is challenged with T. gondii, either directly or via a vector. Only a few live, attenuated T. gondii strains used for immunization have been able to confer protective immunity, which is measured by a lack of tissue cysts after challenge. Furthermore, challenge with low virulence strains, especially strains with genotype II, will probably be insufficient to provide protection against the more virulent T. gondii strains, such as those with genotypes I or II, or those genotypes from South America not belonging to genotype I, II or III. Future studies should use animal models besides rodents, and challenges should be performed with at least one genotype II T. gondii and one of the more virulent genotypes. Endpoints like maternal-foetal transmission and prevention of eye disease are important in addition to the traditional endpoint of survival or reduction in numbers of brain cysts after challenge
Robust and Task-Independent Spatial Profile of the Visual Word Form Activation in Fusiform Cortex
Written language represents a special category of visual information. There is strong evidence for the existence of a cortical region in ventral occipitotemporal cortex for processing the visual form of written words. However, due to inconsistent findings obtained with different tasks, the level of specialization and selectivity of this so called visual word form area (VWFA) remains debated. In this study, we examined category selectivity for Chinese characters, a non-alphabetic script, in native Chinese readers. In contrast to traditional approaches of examining response levels in a restricted predefined region of interest (ROI), a detailed distribution of the BOLD signal across the mid-fusiform cortical surface and the spatial patterns of responses to Chinese characters were obtained. Results show that a region tuned for Chinese characters could be consistently found in the lateral part of the left fusiform gyrus in Chinese readers, and this spatial pattern of selectivity for written words was not influenced by top-down tasks such as phonological or semantic modulations. These results provide strong support for the robust spatial coding of category selective response in the mid-fusiform cortex, and demonstrate the utility of the spatial distribution analysis as a more meaningful approach to examine functional magnetic resonance imaging (fMRI) data
Automated Home-Cage Behavioural Phenotyping of Mice
Neurobehavioral analysis of mouse phenotypes requires the monitoring of mouse behavior over long
periods of time. Here, we describe a trainable computer vision system enabling the automated analysis
of complex mouse behaviors. We provide software and an extensive manually annotated video
database used for training and testing the system. Our system performs on par with human scoring, as
measured from ground-truth manual annotations of thousands of clips of freely behaving mice. As a
validation of the system, we characterized the home-cage behaviors of two standard inbred and two
non-standard mouse strains. From this data we were able to predict in a blind test the strain identity of
individual animals with high accuracy. Our video-based software will complement existing sensor
based automated approaches and enable an adaptable, comprehensive, high-throughput, fine-grained,
automated analysis of mouse behavior.McGovern Institute for Brain ResearchCalifornia Institute of Technology. Broad Fellows Program in Brain CircuitryNational Science Council (China) (TMS-094-1-A032
VEGF attenuates development from cardiac hypertrophy to heart failure after aortic stenosis through mitochondrial mediated apoptosis and cardiomyocyte proliferation
<p>Abstract</p> <p>Background</p> <p>Aortic stenosis (AS) affects 3 percent of persons older than 65 years and leads to greater morbidity and mortality than other cardiac valve diseases. Surgery with aortic valve replacement (AVR) for severe symptomatic AS is currently the only treatment option. Unfortunately, in patients with poor ventricular function, the mortality and long-term outcome is unsatisfied, and only a minority of these patients could bear surgery. Our previous studies demonstrated that vascular endothelial growth factor (VEGF) protects cardiac function in myocardial infarction model through classic VEGF-PI3k-Akt and unclear mitochondrial anti-apoptosis pathways; promoting cardiomyocyte (CM) proliferation as well. The present study was designed to test whether pre-operative treatment with VEGF improves AS-induced cardiac dysfunction, to be better suitable for AVR, and its potential mechanism.</p> <p>Methods</p> <p>Adult male mice were subjected to AS or sham operation. Two weeks later, adenoviral VEGF (Ad-VEGF), enhanced green fluorescence protein (Ad-EGFP, as a parallel control) or saline was injected into left ventricle free wall. Two weeks after delivery, all mice were measured by echocardiography and harvested for further detection.</p> <p>Results</p> <p>AS for four weeks caused cardiac hypertrophy and left ventricular dysfunction. VEGF treatment increased capillary density, protected mitochondrial function, reduced CMs apoptosis, promoted CMs proliferation and eventually preserved cardiac function.</p> <p>Conclusions</p> <p>Our findings indicate that VEGF could repair AS-induced transition from compensatory cardiac hypertrophy to heart failure.</p
Onset and evolution of discontinuously segmented chip flow in ultra-high-speed cutting Ti-6Al-4V
Increasing the cutting speed to an ultra-high level usually gives rise to a chip flow transition from continuously serrated to discontinuously segmented, which is one of the most fundamental and challenging problems in metal cutting. In this work, we experimentally performed the ultra-high-speed cutting on Ti-6Al-4V with a maximum cutting speed of 210 m/s, focusing on the physical phenomena accompanying the discontinuously segmented chip flow. It reveals that the discontinuously segmented chip flow can be attributed to the shear fracture induced by the fully matured shear banding, and there exists a ductile-brittle transition of the shear fracture as the cutting speed increases to an ultra-high level. In addition, the critical condition for the onset of segmented chip flow is presented using the momentum diffusion-based shear band evolution model, which gives good prediction for the chip segmentation
Effect of high energy X-ray irradiation on the nano-mechanical properties of human enamel and dentine
Observation of a ppb mass threshoud enhancement in \psi^\prime\to\pi^+\pi^-J/\psi(J/\psi\to\gamma p\bar{p}) decay
The decay channel
is studied using a sample of events collected
by the BESIII experiment at BEPCII. A strong enhancement at threshold is
observed in the invariant mass spectrum. The enhancement can be fit
with an -wave Breit-Wigner resonance function with a resulting peak mass of
and a
narrow width that is at the 90% confidence level.
These results are consistent with published BESII results. These mass and width
values do not match with those of any known meson resonance.Comment: 5 pages, 3 figures, submitted to Chinese Physics
Adherence to routine use of pharmacological prophylaxis of heterotopic ossification after total hip arthroplasty: results from an Italian multicenter, prospective, observational survey
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