309 research outputs found
The Effect of Botanical Tinctures and Essential Oils on the Growth and Morphogenesis of Candida albicans
Objective: Candida albicans is an opportunistic and polymorphic fungal pathogen that affects mucosal membranes and squamous epithelia as well as being part of the normal human flora. Historically, there have been many botanical-based remedies used to treat fungal conditions, including C. albicans. This study examined the efficacy of both botanical tinctures and essential oils on the growth and morphological differentiation of C. albicans. Methods: The in vitro growth and differentiation of C. albicans was monitored following treatment with ethanol-based tinctures and essential oils prepared from several commonly used botanicals. Results: Results demonstrated that all ethanol-based botanical tinctures tested did not inhibit the growth of C. albicans, but several tinctures, including Marsdenia condurango, Juglans nigra (Black walnut), Anemopsis californica (Yerba mansa) and Piper cubeba (Cubeb berry), significantly reduced the morphological differentiation of the yeast into the invasive hyphae form. Alternatively, several botanical essential oils, including those from Thymus vulgaris (Thyme), Rosmarinus officinalis (Rosemary) and Cymbopogon citratus (Lemon grass) had a dramatic effect on inhibiting the growth of C. albicans. Conclusions: These results suggest that botanical tinctures commonly used in the treatment of C. albicans infections may act by blocking the differentiation of the yeast into a more virulent hyphal form while not affecting the growth rate. In comparison, therapeutic essential oils may target both the differentiation and growth rate of C. albicans. The results support that different active constituents are present in botanical tinctures as compared to oils thereby contributing to our understanding of how these botanicals may be effective therapeutics in the treatment of C. albicans infections
Inner speech deficits in people with aphasia
Despite the ubiquity of inner speech in our mental lives, methods for objectively assessing inner speech capacities remain underdeveloped. The most common means of assessing inner speech is to present participants with tasks requiring them to silently judge whether two words rhyme. We developed a version of this task to assess the inner speech of a population of patients with aphasia and corresponding language production deficits. Patientsā performance on the silent rhyming task was severely impaired relative to controls. Patientsā performance on this task did not, however, correlate with their performance on a variety of other standard tests of overt language and rhyming abilities. In particular, patients who were generally unimpaired in their abilities to overtly name objects during confrontation naming tasks, and who could reliably judge when two words spoken to them rhymed, were still severely impaired (relative to controls) at completing the silent rhyme task. A variety of explanations for these results are considered, as a means to critically reflecting on the relation between inner speech and silent rhyme judgments more generally
GCN2-dependent phosphorylation of eukaryotic translation initiation factor-2Ī± in Arabidopsis
The yeast regulatory protein kinase, general control non-derepressible-2 (GCN2) plays a key role in general amino acid control. GCN2 phosphorylates the Ī± subunit of the trimeric eukaryotic translation initiation factor-2 (eIF2), bringing about a decrease in the general rate of protein synthesis but an increase in the synthesis of GCN4, a transcription factor that promotes the expression of genes encoding enzymes for amino acid biosynthesis. The present study concerned the phosphorylation of Arabidopsis eIF2Ī± (AteIF2Ī±) by the Arabidopsis homologue of GCN2, AtGCN2, and the role of AtGCN2 in regulating genes encoding enzymes of amino acid biosynthesis and responding to virus infection. A null mutant for AtGCN2 called GT8359 was obtained and western analysis confirmed that it lacked AtGCN2 protein. GT8359 was more sensitive than wild-type Arabidopsis to herbicides that affect amino acid biosynthesis. Phosphorylation of AteIF2Ī± occurred in response to herbicide treatment but only in wild-type Arabidopsis, not GT8359, showing it to be AtGCN2-dependent. Expression analysis of genes encoding key enzymes for amino acid biosynthesis and nitrate assimilation revealed little effect of loss of AtGCN2 function in GT8359 except that expression of a nitrate reductase gene, NIA1, was decreased. Analysis of wild-type and GT8359 plants infected with Turnip yellow mosaic virus or Turnip crinkle virus showed that AteIF2Ī± was not phosphorylated
Assessing abstract thought and its relation to language with a new nonverbal paradigm: Evidence from aphasia
In recent years, language has been shown to play a number of important cognitive roles over and above the communication of thoughts. One hypothesis gaining support is that language facilitates thought about abstract categories, such as democracy or prediction. To test this proposal, a novel set of semantic memory task trials, designed for assessing abstract thought non-linguistically, were normed for levels of abstractness. The trials were rated as more or less abstract to the degree that answering them required the participant to abstract away from both perceptual features and common setting associations corresponding to the target image. The normed materials were then used with a population of people with aphasia to assess the relationship of abstract thought to language. While the language-impaired group with aphasia showed lower overall accuracy and longer response times than controls in general, of special note is that their response times were significantly longer as a function of a trialās degree of abstractness. Further, the aphasia groupās response times in reporting their degree of confidence (a separate, metacognitive measure) were negatively correlated with their language production abilities, with lower language scores predicting longer metacognitive response times. These results provide some support for the hypothesis that language is an important aid to abstract thought and to metacognition about abstract thought
Probing potassium in the atmosphere of HD 80606b with tunable filter transit spectrophotometry from the Gran Telescopio Canarias
We report observations of HD 80606 using the 10.4-m Gran Telescopio Canarias
(GTC) and the OSIRIS tunable filter imager. We acquired very-high-precision,
narrow-band photometry in four bandpasses around the K I absorption feature
during the January 2010 transit of HD 80606b and during out-of-transit
observations conducted in January and April of 2010. We obtained differential
photometric precisions of \sim 2.08e-4 for the in-transit flux ratio measured
at 769.91-nm, which probes the K I line core. We find no significant difference
in the in-transit flux ratio between observations at 768.76 and 769.91 nm. Yet,
we find a difference of \sim 8.09 \pm 2.88e-4 between these observations and
observations at a longer wavelength that probes the K I wing (777.36 nm). While
the presence of red noise in the transit data has a non-negligible effect on
the uncertainties in the flux ratio, the 777.36-769.91 nm colour during transit
shows no effects from red noise and also indicates a significant colour change,
with a mean value of \sim 8.99\pm0.62e-4. This large change in the colour is
equivalent to a \sim 4.2% change in the apparent planetary radius with
wavelength, which is much larger than the atmospheric scale height. This
implies the observations probed the atmosphere at very low pressures as well as
a dramatic change in the pressure at which the slant optical depth reaches
unity between \sim770 and 777 nm. We hypothesize that the excess absorption may
be due to K I in a high-speed wind being driven from the exoplanet's exosphere.
We discuss the viability of this and alternative interpretations, including
stellar limb darkening, starspots, and effects from Earth's atmosphere. We
strongly encourage follow-up observations of HD 80606b to confirm the signal
measured here. Finally, we discuss the future prospects for exoplanet
characterization using tunable filter spectrophotometry.Comment: Accepted to MNRAS; revised version includes some major updates; now
21 pages, with 14 figures and 9 table
Disequilibrium Carbon, Oxygen, and Nitrogen Chemistry in the Atmospheres of HD 189733b and HD 209458b
We have developed 1-D photochemical and thermochemical kinetics and diffusion
models for the transiting exoplanets HD 189733b and HD 209458b to study the
effects of disequilibrium chemistry on the atmospheric composition of "hot
Jupiters." Here we investigate the coupled chemistry of neutral carbon,
hydrogen, oxygen, and nitrogen species, and we compare the model results with
existing transit and eclipse observations. We find that the vertical profiles
of molecular constituents are significantly affected by transport-induced
quenching and photochemistry, particularly on cooler HD 189733b; however, the
warmer stratospheric temperatures on HD 209458b can help maintain
thermochemical equilibrium and reduce the effects of disequilibrium chemistry.
For both planets, the methane and ammonia mole fractions are found to be
enhanced over their equilibrium values at pressures of a few bar to less than a
mbar due to transport-induced quenching, but CH4 and NH3 are photochemically
removed at higher altitudes. Atomic species, unsaturated hydrocarbons
(particularly C2H2), some nitriles (particularly HCN), and radicals like OH,
CH3, and NH2 are enhanced overequilibrium predictions because of quenching and
photochemistry. In contrast, CO, H2O, N2, and CO2 more closely follow their
equilibrium profiles, except at pressures < 1 microbar, where CO, H2O, and N2
are photochemically destroyed and CO2 is produced before its eventual
high-altitude destruction. The enhanced abundances of HCN, CH4, and NH3 in
particular are expected to affect the spectral signatures and thermal profiles
HD 189733b and other, relatively cool, close-in transiting exoplanets. We
examine the sensitivity of our results to the assumed temperature structure and
eddy diffusion coefficientss and discuss further observational consequences of
these models.Comment: 40 pages, 16 figures, accepted for publication in Astrophysical
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