In vitro bioconversion of polyphenols from black tea and red wine/grape juice by human intestinal microbiota displays strong interindividual variability

Dietary polyphenols in tea and wine have been associated with beneficial health effects. After ingestion, most polyphenols are metabolized by the colonic microbiota. The current study aimed at exploring the interindividual variation of gut microbial polyphenol bioconversion from 10 healthy human subjects. In vitro fecal batch fermentations simulating conditions in the distal colon were performed using polyphenols from black tea and a mixture of red wine and grape juice. Microbial bioconversion was monitored by NMR- and GC-MS-based profiling of diverse metabolites and phenolics. The complex polyphenol mixtures were degraded to a limited number of key metabolites. Each subject displayed a specific metabolite profile differing in composition and time courses as well as levels of these metabolites. Moreover, clear differences depending on the polyphenol sources were observed. In conclusion, varying metabolite pathways among individuals result in different metabolome profiles and therefore related health effects are hypothesized to differ between subjects

Closed-Loop, Open-Source Electrophysiology

Multiple extracellular microelectrodes (multi-electrode arrays, or MEAs) effectively record rapidly varying neural signals, and can also be used for electrical stimulation. Multi-electrode recording can serve as artificial output (efferents) from a neural system, while complex spatially and temporally targeted stimulation can serve as artificial input (afferents) to the neuronal network. Multi-unit or local field potential (LFP) recordings can not only be used to control real world artifacts, such as prostheses, computers or robots, but can also trigger or alter subsequent stimulation. Real-time feedback stimulation may serve to modulate or normalize aberrant neural activity, to induce plasticity, or to serve as artificial sensory input. Despite promising closed-loop applications, commercial electrophysiology systems do not yet take advantage of the bidirectional capabilities of multi-electrodes, especially for use in freely moving animals. We addressed this lack of tools for closing the loop with NeuroRighter, an open-source system including recording hardware, stimulation hardware, and control software with a graphical user interface. The integrated system is capable of multi-electrode recording and simultaneous patterned microstimulation (triggered by recordings) with minimal stimulation artifact. The potential applications of closed-loop systems as research tools and clinical treatments are broad; we provide one example where epileptic activity recorded by a multi-electrode probe is used to trigger targeted stimulation, via that probe, to freely moving rodents

A Low-Cost Multielectrode System for Data Acquisition Enabling Real-Time Closed-Loop Processing with Rapid Recovery from Stimulation Artifacts

Commercially available data acquisition systems for multielectrode recording from freely moving animals are expensive, often rely on proprietary software, and do not provide detailed, modifiable circuit schematics. When used in conjunction with electrical stimulation, they are prone to prolonged, saturating stimulation artifacts that prevent the recording of short-latency evoked responses. Yet electrical stimulation is integral to many experimental designs, and critical for emerging brain-computer interfacing and neuroprosthetic applications. To address these issues, we developed an easy-to-use, modifiable, and inexpensive system for multielectrode neural recording and stimulation. Setup costs are less than US$10,000 for 64 channels, an order of magnitude lower than comparable commercial systems. Unlike commercial equipment, the system recovers rapidly from stimulation and allows short-latency action potentials (<1 ms post-stimulus) to be detected, facilitating closed-loop applications and exposing neural activity that would otherwise remain hidden. To illustrate this capability, evoked activity from microstimulation of the rodent hippocampus is presented. System noise levels are similar to existing platforms, and extracellular action potentials and local field potentials can be recorded simultaneously. The system is modular, in banks of 16 channels, and flexible in usage: while primarily designed for in vivo use, it can be combined with commercial preamplifiers to record from in vitro multielectrode arrays. The system's open-source control software, NeuroRighter, is implemented in C#, with an easy-to-use graphical interface. As C# functions in a managed code environment, which may impact performance, analysis was conducted to ensure comparable speed to C++ for this application. Hardware schematics, layout files, and software are freely available. Since maintaining wired headstage connections with freely moving animals is difficult, we describe a new method of electrode-headstage coupling using neodymium magnets

Feynman-Schwinger representation approach to nonperturbative physics

The Feynman-Schwinger representation provides a convenient framework for the cal culation of nonperturbative propagators. In this paper we first investigate an analytically solvable case, namely the scalar QED in 0+1 dimension. With this toy model we illustrate how the formalism works. The analytic result for the self energy is compared with the perturbative result. Next, using a $\chi^2\phi$ interaction, we discuss the regularization of various divergences encountered in this formalism. The ultraviolet divergence, which is common in standard perturbative field theory applications, is removed by using a Pauli-Villars regularization. We show that the divergence associated with large values of Feynman-Schwinger parameter $s$ is spurious and it can be avoided by using an imaginary Feynman parameter $is$.Comment: 26 pages, 9 figures, minor correctio

Evidence for Non-perturbative String Symmetries

String theory appears to admit a group of discrete field transformations -- called $S$ dualities -- as exact non-perturbative quantum symmetries. Mathematically, they are rather analogous to the better-known $T$ duality symmetries, which hold perturbatively. In this talk the evidence for $S$ duality is reviewed and some speculations are presented.Comment: Error corrected and reference added; 10 pages, latex, no figures, conference Repor

Exchange-Correlation Hole of a Generalized Gradient Approximation for Solids and Surfaces

We propose a generalized gradient approximation (GGA) for the angle- and system-averaged exchange-correlation hole of a many-electron system. This hole, which satisfies known exact constraints, recovers the PBEsol (Perdew-Burke-Ernzerhof for solids) exchange-correlation energy functional, a GGA that accurately describes the equilibrium properties of densely packed solids and their surfaces. We find that our PBEsol exchange-correlation hole describes the wavevector analysis of the jellium exchange-correlation surface energy in agreement with a sophisticated time-dependent density-functional calculation (whose three-dimensional wavevector analysis we report here).Comment: 7 pages, 9 figure

"The daily grunt": middle class bias and vested interests in the 'Getting in Early' and 'Why Can't They Read?' reports.

It is a long-standing and commonly held belief in the UK and elsewhere that the use of elite forms of language reflects superior intellect and education. Expert opinion from sociolinguistics, however, contends that such a view is the result of middle-class bias and cannot be scientifically justified. In the 1960s and 1970s,such luminaries as Labov (1969) and Trudgill (1975) were at pains to point out to educationalists, with some success, that this 'deficit 'view of working-class children's communicative competence is not a helpful one. However, a close reading of recent think-tank reports and policy papers on language and literacy teaching in schools reveals that the linguistic deficit hypothesis has resurfaced and is likely to influence present-day educational policy and practice. In this paper I examine in detail the findings, claims and recommendations of the reports and I argue that they are biased, poorly researched and reflect the vested interests of certain specialist groups, such as speech and language therapists and companies who sell literacy materials to schools. I further argue that we need to, once again, inject the debate with the social dimensions of educational failure, and we need to move away from the pathologisation of working-class children's language patterns

Age-related differences in emotional reactivity, regulation, and rejection sensitivity in adolescence

Although adolescents’ emotional lives are thought to be more turbulent than those of adults, it is unknown whether this difference is attributable to developmental changes in emotional reactivity or emotion regulation. Study 1 addressed this question by presenting healthy individuals aged 10–23 with negative and neutral pictures and asking them to respond naturally or use cognitive reappraisal to down-regulate their responses on a trial-by-trial basis. Results indicated that age exerted both linear and quadratic effects on regulation success but was unrelated to emotional reactivity. Study 2 replicated and extended these findings using a different reappraisal task and further showed that situational (i.e., social vs. nonsocial stimuli) and dispositional (i.e., level of rejection sensitivity) social factors interacted with age to predict regulation success: young adolescents were less successful at regulating responses to social than to nonsocial stimuli, particularly if the adolescents were high in rejection sensitivity. Taken together, these results have important implications for the inclusion of emotion regulation in models of emotional and cognitive development.National Science Foundation (U.S.) (Award BCS-0224342)National Institutes of Health (U.S.) (Award MH076137)National Institutes of Health (U.S.) (Award HD069178)National Institutes of Health (U.S.) (Award MH094056

Glassy Transition and Aging in a Model without Disorder

We study the off-equilibrium relaxational dynamics of the Amit-Roginsky $\phi^3$ field theory, for which the mode coupling approximation is exact. We show that complex phenomena such as aging and ergodicity breaking are present at low temperature, similarly to what is found in long range spin glasses. This is a generalization of mode coupling theory of the structural glass transition to off-equilibrium situations.Comment: 9 pages, 1 uuencoded figure, LaTex, preprint NORDITA 94/3