8,721 research outputs found
Dispatches from the interface of salivary bioscience and neonatal research.
The emergence of the interdisciplinary field of salivary bioscience has created opportunity for neonatal researchers to measure multiple components of biological systems non-invasively in oral fluids. The implications are profound and potentially high impact. From a single oral fluid specimen, information can be obtained about a vast array of biological systems (e.g., endocrine, immune, autonomic nervous system) and the genetic polymorphisms related to individual differences in their function. The purpose of this review is to describe the state of the art for investigators interested in integrating these unique measurement tools into the current and next generation of research on gonadal steroid exposure during the prenatal and neonatal developmental periods
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Uric Acid as a Potential Peripheral Biomarker for Disease Features in Huntington's Patients.
Oxidative stress has long been implicated in the pathophysiology and progression of Huntington's disease (HD). Uric acid (UA) is a naturally occurring antioxidant that is present in the brain and periphery. Growing evidence has implicated UA as a molecular biomarker for several neurodegenerative diseases, most notably Parkinson's disease (PD). In this study, we investigated UA levels in clinical samples from HD patients and normal controls (NCs) and assessed potential relationships between UA levels and disease and clinical data. UA levels were measured in plasma (n = 107) and saliva (n = 178) samples from premanifest (pre-HD) and manifest HD patients and control subjects. Gender effects of UA levels were observed in both biofluids, with male patients showing higher UA levels compared to female patients. Comparisons of UA levels across diagnostic groups, separated by gender, revealed that both plasma and salivary UA levels were significantly lower in female pre-HD and manifest HD patients compared to NCs. Salivary levels of UA were also significantly lower in male manifest HD patients versus controls, but not in plasma. Correlations of peripheral UA levels to clinical data also showed differences according to gender. In male HD patients, both plasma and salivary UA levels were significantly negatively correlated with total functional capacity (TFC), while positive correlations were observed with total motor score (TMS). Female HD patients showed a significant positive correlation between plasma UA levels and TMS, while salivary UA levels from female patients were significantly correlated to disease burden. Finally, in a separate cohort, we show that UA levels are decreased in postmortem prefrontal cortical samples (n = 20) from HD subjects compared to matched controls. These findings suggest that decreased levels of UA in the brains of HD patients can be reflected in peripheral fluids, with salivary measures of UA particularly offering significant promise as a potentially relevant, non-invasive biomarker of disease symptoms and burden. Our findings further highlight the impact of sexual dimorphism in HD pathophysiology
Few-electron quantum dots in III-V ternary alloys: role of fluctuations
We study experimentally the electron transport properties of gated quantum
dots formed in InGaAs/InP and InAsP/InP quantum well structures grown by
chemical-beam epitaxy. For the case of the InGaAs quantum well, quantum dots
form directly underneath narrow gate electrodes due to potential fluctuations.
We measure the Coulomb-blockade diamonds in the few-electron regime of a single
quantum dot and observe photon-assisted tunneling peaks under microwave
irradiation. A singlet-triplet transition at high magnetic field and
Coulomb-blockade effects in the quantum Hall regime are also observed. For the
InAsP quantum well, an incidental triple quantum dot forms also due to
potential fluctuations within a single dot layout. Tunable quadruple points are
observed via transport measurements.Comment: 3.3 pages, 3 figures. Added two new subfigures, new references, and
improved the tex
Reducing the Bias of Causality Measures
Measures of the direction and strength of the interdependence between two
time series are evaluated and modified in order to reduce the bias in the
estimation of the measures, so that they give zero values when there is no
causal effect. For this, point shuffling is employed as used in the frame of
surrogate data. This correction is not specific to a particular measure and it
is implemented here on measures based on state space reconstruction and
information measures. The performance of the causality measures and their
modifications is evaluated on simulated uncoupled and coupled dynamical systems
and for different settings of embedding dimension, time series length and noise
level. The corrected measures, and particularly the suggested corrected
transfer entropy, turn out to stabilize at the zero level in the absence of
causal effect and detect correctly the direction of information flow when it is
present. The measures are also evaluated on electroencephalograms (EEG) for the
detection of the information flow in the brain of an epileptic patient. The
performance of the measures on EEG is interpreted, in view of the results from
the simulation study.Comment: 30 pages, 12 figures, accepted to Physical Review
A Tuneable Few Electron Triple Quantum Dot
In this paper we report on a tuneable few electron lateral triple quantum dot
design. The quantum dot potentials are arranged in series. The device is aimed
at studies of triple quantum dot properties where knowing the exact number of
electrons is important as well as quantum information applications involving
electron spin qubits. We demonstrate tuning strategies for achieving required
resonant conditions such as quadruple points where all three quantum dots are
on resonance. We find that in such a device resonant conditions at specific
configurations are accompanied by novel charge transfer behaviour.Comment: 11 pages, 4 figure
The Effects of Over Drying, Before the Size Press on Strength Properties
This thesis was designed to determine the effects of moisture variations before the size press, and its effects on strength properties. This experiment involved laboratory experimentation along with a paper program pilot plant two day trial.
The results from the laboratory data revealed that an increased moisture content into the size press resulted in an increase in overall strength content for tests including tear, burst, and fold. The pilot plant trial data showed a specific window effect, in that at very low/high moisture levels entering the size press, a significant decrease in strength could be seen.
It was also found that upon increased moisture content, an increased weight of starch was picked up by the web, however, this had little effect on overall strength properties. Finally, by completion of a mass and energy balance, it was determined that a consecutive increase in energy was needed to reach the lower moisture levels entering the size press; taking into account that moisture was held constant at the reel. This led to steam optimization which could be seen in ($/year)
Alien Registration- Granger, George A. (Boothbay, Lincoln County)
https://digitalmaine.com/alien_docs/13219/thumbnail.jp
Two-stage Kondo effect in a four-electron artificial atom
An artificial atom with four electrons is driven through a singlet-triplet
transition by varying the confining potential. In the triplet, a Kondo peak
with a narrow dip at drain-source voltage V_ds=0 is observed. The low energy
scale V_ds* characterizing the dip is consistent with predictions for the
two-stage Kondo effect. The phenomenon is studied as a function of temperature
T and magnetic field B, parallel to the two-dimensional electron gas. The low
energy scales T* and B* are extracted from the behavior of the zero-bias
conductance and are compared to the low energy scale V_ds* obtained from the
differential conductance. Good agreement is found between kT* and |g|muB*, but
eV_ds* is larger, perhaps because of nonequilibrium effects.Comment: 7 pages, 7 figures. Added labels on Fig. 3f and one referenc
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