12,237 research outputs found
Screening forCronobacterSpecies in Powdered and Reconstituted Infant Formulas and from Equipment Used in Formula Preparation in Maternity Hospitals
Background/Aims: Cronobacter spp. have been identified as being of considerable risk to neonates. The occurrence of organism in infant formulas is therefore of considerable interest. Methods: The occurrence of Cronobacter spp. in infant feeds (formulas and fortified cow’s milk) was determined using most probable number (MPN) analysis, and from formula preparation utensils. Ninety nine samples were analyzed, of which 42 were unopened cans of powdered infant formula (PIF), 25 reconstituted infant formulas in feeding bottles, 27 utensils used from the preparation of infant formula, and 5 samples of fortified cow’s milk. Presumptive Cronobacter spp. isolates were identified using the 7 allele multilocus sequence typing (MLST) scheme. Results: C. sakazakii, C. malonaticus and C. muytjensii were recovered from PIF. Although the incidence of Cronobacter in PIF was 29% (12/42), the level was low with an average of 0.54 MPN/100g. According to MLST profiling, C. sakazakii was the most frequently isolated Cronobacter species, and C. sakazakii ST4 (associated with neonatal meningitis) was recovered from 2/42 PIF samples at 0.51 and 0.92 MPN/100g. Conclusions: Cronobacter spp. can be isolated from PIF and therefore strict hygienic practices during PIF preparation are important to minimize neonate exposure and reduce the risk of severe infections
Adaptable history biases in human perceptual decisions
When making choices under conditions of perceptual uncertainty, past experience can play a vital role. However, it can also lead to biases that worsen decisions. Consistent with previous observations, we found that human choices are influenced by the success or failure of past choices even in a standard two-alternative detection task, where choice history is irrelevant. The typical bias was one that made the subject switch choices after a failure. These choice history biases led to poorer performance and were similar for observers in different countries. They were well captured by a simple logistic regression model that had been previously applied to describe psychophysical performance in mice. Such irrational biases seem at odds with the principles of reinforcement learning, which would predict exquisite adaptability to choice history. We therefore asked whether subjects could adapt their irrational biases following changes in trial order statistics. Adaptability was strong in the direction that confirmed a subject's default biases, but weaker in the opposite direction, so that existing biases could not be eradicated. We conclude that humans can adapt choice history biases, but cannot easily overcome existing biases even if irrational in the current context: adaptation is more sensitive to confirmatory than contradictory statistics
Follicular Fluid redox involvement for ovarian follicle growth
As the human ovarian follicle enlarges in the course of a regular cycle or following controlled ovarian stimulation, the changes in its structure reveal the oocyte environment composed of cumulus oophorus cells and the follicular fluid (FF).In contrast to the dynamic nature of cells, the fluid compartment appears as a reservoir rich in biomolecules. In some aspects, it is similar to the plasma, but it also exhibits differences that likely relate to its specific localization around the oocyte. The chemical composition indicates that the follicular fluid is able to detect and buffer excessive amounts of reactive oxygen species, employing a variety of antioxidants, some of them components of the intracellular milieu.An important part is played by albumin through specific cysteine residues. But the fluid contains other molecules whose cysteine residues may be involved in sensing and buffering the local oxidative conditions. How these molecules are recruited and regulated to intervene such process is unknown but it is a critical issue in reproduction.In fact, important proteins in the FF, that regulate follicle growth and oocyte quality, exhibit cysteine residues at specific points, whose untoward oxidation would result in functional loss. Therefore, preservation of controlled oxidative conditions in the FF is a requirement for the fine-tuned oocyte maturation process. In contrast, its disturbance enhances the susceptibility to the establishment of reproductive disorders that would require the intervention of reproductive medicine technology.info:eu-repo/semantics/publishedVersio
Object Manipulation in Virtual Reality Under Increasing Levels of Translational Gain
Room-scale Virtual Reality (VR) has become an affordable consumer reality, with applications ranging from entertainment to productivity. However, the limited physical space available for room-scale VR in the typical home or office environment poses a significant problem. To solve this, physical spaces can be extended by amplifying the mapping of physical to virtual movement (translational gain). Although amplified movement has been used since the earliest days of VR, little is known about how it influences reach-based interactions with virtual objects, now a standard feature of consumer VR. Consequently, this paper explores the picking and placing of virtual objects in VR for the first time, with translational gains of between 1x (a one-to-one mapping of a 3.5m*3.5m virtual space to the same sized physical space) and 3x (10.5m*10.5m virtual mapped to 3.5m*3.5m physical). Results show that reaching accuracy is maintained for up to 2x gain, however going beyond this diminishes accuracy and increases simulator sickness and perceived workload. We suggest gain levels of 1.5x to 1.75x can be utilized without compromising the usability of a VR task, significantly expanding the bounds of interactive room-scale VR
Solar wind speed theory and the nonextensivity of solar corona
The solar corona is a complex system, with nonisothermal plasma and being in
the self-gravitating field of the Sun. So the corona plasma is not only a
nonequilibrium system but also a nonextensive one. We estimate the parameter of
describing the degree of nonextensivity of the corona plasma and study the
generalization of the solar wind speed theory in the framework of nonextensive
statistical mechanics. It is found that, when use Chapman's corona model (1957)
as the radial distribution of the temperature in the corona, the nonextensivity
reduces the gas pressure outward and thus leads a significant deceleration
effect on the radial speed of the solar wind.Comment: 12 pages,1 figure, 1 table, 21 references; UN/ESA/NASA Workshop on
Basic Space Science and the International Heliophysical Year 2007, National
Astronomical Observatory of Japan, 18-22 June, 2007, Tokyo, Japa
Five really easy steps to build a homemade low-cost simulator
AIM:
The aim of this study was to evaluate how simple it is to build a homemade low-cost simulator using a simple 5-step scheme.
METHODS:
A scheme explaining how to build an endoscopic surgery simulator in 5 easy steps was presented to 26 surgeons. The simulator required a pair of scissors and easy-to-find materials. Its total cost was less than €35. The participants assessed the simulator using common endoscopic training toys or ex vivo tissue and completed an anonymous query comparing it with other commercial simulators that they had experienced before.
RESULTS:
In all, 84.6% found the simulator really easy to build. Every participant felt that he or she could do the same simulator themselves. Comparing with other commercial available box simulators, the majority of participants found the homemade simulator easier to (a) mount and dismount, (b) transport, (c) clean, and (d) use when practicing alone.
CONCLUSIONS:
Anyone can build its own simulator for a small amount of money
Herpes Simplex Encephalitis Does Interferon Care?
Introduction and aims: Herpes simplex encephalitis (HSE) is an acute, life-threatening disease, requiring prompt intervention. TLR3-interferon (IFN) axis defects in the antiviral innate immune response against HSV-1 and some genes (TLR3, UNC93B1 and TRAF3) probably play an important role in HSE pathogenesis.
Methods: Descriptive study between January 2007 and December 2012 from HSE patients treated with acyclovir (initiated between D2 to D3 of illness) and INF alpha-2b. HSV-1 was detected by PCR from CSF. PBMC and fibroblasts were studied for their IFN responses to TLR3 and virus stimulations. Coding exons of the known HSE-associated genes were sequenced.
Results: Six cases, aged between 7 months and 11 years, with seizures and extensive brain injury. Interferon was initiated between D3 and D18. Patient 1 initiated IFN on D18 and stopped 7 days later for bicytopenia. Patient 2 started on D3 and has no sequelae. Patient 4 started on D5 and has persistent right sided hemiparesis. Patient 3, 5 and 6 started on D5, D3 and D7 respectively remain with epilepsy under medical control. Only Patient 1, who started IFN later than D7, has sequelar tetraparesis. None of the other patients have severe neurological deficits. The functional studies were normal, except for patient 1 whose fibroblasts displayed impaired IFN-lambda production after stimulations of poly(I:C), thought to be TLR3-dependent. No mutation was found in the sequenced coding exons of UNC93B1, TLR3 and TRAF3.
Conclusions: Although a small sample, our results suggest that IFN therapy should be considered in the treatment of HSE.info:eu-repo/semantics/publishedVersio
Classical and Quantum Solitons in the Symmetric Space Sine-Gordon Theories
We construct the soliton solutions in the symmetric space sine-Gordon
theories. The latter are a series of integrable field theories in
1+1-dimensions which are associated to a symmetric space F/G, and are related
via the Pohlmeyer reduction to theories of strings moving on symmetric spaces.
We show that the solitons are kinks that carry an internal moduli space that
can be identified with a particular co-adjoint orbit of the unbroken subgroup H
of G. Classically the solitons come in a continuous spectrum which encompasses
the perturbative fluctuations of the theory as the kink charge becomes small.
We show that the solitons can be quantized by allowing the collective
coordinates to be time-dependent to yield a form of quantum mechanics on the
co-adjoint orbit. The quantum states correspond to symmetric tensor
representations of the symmetry group H and have the interpretation of a fuzzy
geometric version of the co-adjoint orbit. The quantized finite tower of
soliton states includes the perturbative modes at the base.Comment: 53 pages, additional comments and small errors corrected, final
journal versio
- …