1,366 research outputs found
Predicting chemical environments of bacteria from receptor signaling
Sensory systems have evolved to respond to input stimuli of certain
statistical properties, and to reliably transmit this information through
biochemical pathways. Hence, for an experimentally well-characterized sensory
system, one ought to be able to extract valuable information about the
statistics of the stimuli. Based on dose-response curves from in vivo
fluorescence resonance energy transfer (FRET) experiments of the bacterial
chemotaxis sensory system, we predict the chemical gradients chemotactic
Escherichia coli cells typically encounter in their natural environment. To
predict average gradients cells experience, we revaluate the phenomenological
Weber's law and its generalizations to the Weber-Fechner law and fold-change
detection. To obtain full distributions of gradients we use information theory
and simulations, considering limitations of information transmission from both
cell-external and internal noise. We identify broad distributions of
exponential gradients, which lead to log-normal stimuli and maximal drift
velocity. Our results thus provide a first step towards deciphering the
chemical nature of complex, experimentally inaccessible cellular
microenvironments, such as the human intestine.Comment: DG and GM contributed equally to this wor
Core-competitive Auctions
One of the major drawbacks of the celebrated VCG auction is its low (or zero)
revenue even when the agents have high value for the goods and a {\em
competitive} outcome could have generated a significant revenue. A competitive
outcome is one for which it is impossible for the seller and a subset of buyers
to `block' the auction by defecting and negotiating an outcome with higher
payoffs for themselves. This corresponds to the well-known concept of {\em
core} in cooperative game theory.
In particular, VCG revenue is known to be not competitive when the goods
being sold have complementarities. A bottleneck here is an impossibility result
showing that there is no auction that simultaneously achieves competitive
prices (a core outcome) and incentive-compatibility.
In this paper we try to overcome the above impossibility result by asking the
following natural question: is it possible to design an incentive-compatible
auction whose revenue is comparable (even if less) to a competitive outcome?
Towards this, we define a notion of {\em core-competitive} auctions. We say
that an incentive-compatible auction is -core-competitive if its
revenue is at least fraction of the minimum revenue of a
core-outcome. We study the Text-and-Image setting. In this setting, there is an
ad slot which can be filled with either a single image ad or text ads. We
design an core-competitive randomized auction and an
competitive deterministic auction for the Text-and-Image
setting. We also show that both factors are tight
Determination of Cadmium and Lead in Vegetables by Stripping Chronopotentiometry
A method for the determination of cadmium and lead
in vegetables by stripping chronopotentiometry,
after digestion of the sample with concentrated
sulphuric acid and dry-ashing, is described. Metal
ions were concentrated as their amalgams on a glassy
carbon-working electrode previously coated with a thin
mercury film and then stripped by a suitable oxidant.
Potential and time data were digitally derived and
E was plotted versus dt/dE, thus increasing both
the sensitivity of the method and the resolution of the
analysis. Quantitative analysis was carried out by the
method of standard additions; a good linearity was
obtained in the range of examined concentrations,
as was shown by the determination coefficients, which
were 0.998 (n= 4) for cadmium and 0.993 (n= 4)
for lead. Recoveries of 85\u2013100% for cadmium and of
84\u201397% for lead were obtained from a sample spiked
at different levels. Accuracy was demonstrated by
analysis of a matching reference sample of cabbage.
The detection limits were 1.8 ng/g of wet mass for
cadmium and 5.1 ng/g of wet mass for lead. The
relative standard deviations (mean of nine determinations),
evaluated on a real sample, were 6.7 and 6.2%,
respectively. Results obtained on 10 different commercial
samples of pepper (Capsicum annuum) and egg
plant (Solanum melongena) were not significantly
different from those obtained by graphite furnace
atomic absorption spectrophotometry. The
average content was in the range 3.1\u201318.6 ng/g for
cadmium and 38.2\u201364.3 ng/g for lead
Post-Mortem Immunohistochemical Evidence of β2-Adrenergic Receptor Expression in the Adrenal Gland
The evidence from post-mortem biochemical studies conducted on cortisol and catecholamines suggest that analysis of the adrenal gland could provide useful information about its role in human pathophysiology and the stress response. Authors designed an immunohistochemical study on the expression of the adrenal β2-adrenergic receptor (β2-AR), a receptor with high-affinity for catecholamines, with the aim to show which zones it is expressed in and how its expression differs in relation to the cause of death. The immunohistochemical study was performed on adrenal glands obtained from 48 forensic autopsies of subjects that died as a result of different pathogenic mechanisms using a mouse monoclonal β2-AR antibody. The results show that immunoreactivity for β2-AR was observed in all adrenal zones. Furthermore, immunoreactivity for β2-AR has shown variation in the localization and intensity of different patterns in relation to the original cause of death. To the best of our knowledge, this is the first study that demonstrates β2-AR expression in the human cortex and provides suggestions on the possible involvement of β2-AR in human cortex hormonal stimulation. In conclusion, the authors provide a possible explanation for the observed differences in expression in relation to the cause of death
Sb-SnO2-Nanosized-Based Resistive Sensors for NO2 Detection
A study over Sb-promoted tin oxide nanopowders for sensing applications is reported. nanopowders pure and promoted with 5 wt% of antimony were prepared by wet chemical methods and widely characterized by TEM, XRD, and XPS techniques. Thick film resistive sensors were fabricated by depositing the synthesized nanopowders by drop-coating on interdigited alumina substrates. The sensing characteristics of the pure and Sb-promoted sensors for the monitoring of trace level of were studied. The response of the sensors to water vapor was also investigated, revealing that Sb acts favorably eliminating the interference of humidity
Cosmetics for acne: indications and recommendations for an evidence-based approach.
AIM:
The aim of this review was to evaluate, by a thorough revision of the literature, the true efficacy of currently available topic and systemic cosmetic acne agents.
METHODS:
The efficacy of currently available cosmetic acne agents has been retrospectively evaluated via thorough revision of the literature on matched electronic databases (PubMed). All retrieved studies, either randomized clinical trials or clinical trials, controlled or uncontrolled were considered.
RESULTS:
Scientific evidence suggests that most cosmetic products for acne may enhance the clinical outcome. Cleansers should be indicated to all acne patients; those containing benzoyl peroxide or azelaic/salicylic acid/triclosan show the best efficacy profile. Sebum-controlling agents containing nicotinamide or zinc acetate may minimize excessive sebum production. Cosmetics with antimicrobial and anti-inflammatory substances such as, respectively, ethyl lactate or phytosphingosine and nicotinamide or resveratrol, may speed acne recovery. Topical corneolytics, including retinaldehyde/glycolic acid or lactic acid, induce a comedolytic effect and may also facilitate skin absorption of topical drugs. Finally, the use of specific moisturizers should be strongly recommended in all acne patients.
CONCLUSION:
Cosmetics, if correctly prescribed, may improve the performance of the therapy, whereas wrong procedures and/or inadequate cosmetics may worsen acne. Cosmetological recommendations may allow clinicians to make informed decisions about the role of various cosmetics and to indentify the appropriate indications and precautions. The choice of the most effective product should take into consideration the ongoing pharmacological therapy and acne type/severity as well
Exceptional response to immunotherapy in association with radiotherapy in patient with breast metastasis from urothelial carcinoma: A case report
Most common sites of metastasis of urothelial carcinoma (UC) are lungs, liver, lymph nodes and bone. Pembrolizumab, a humanized monoclonal antibody directed against programmed cell death protein-1 (PD-1), represents an effective second-line therapy for advanced UC. Radiotherapy has been shown to induce a mechanism of immunogenic cell death (ICD) resulting in immune memory and advantageous systemic effects. We present the first case of breast metastasis (BM) from a UC described in literature who had an exceptional response to second-line therapy with pembrolizumab in association with radiotherapy, showing the efficacy of combining immunotherapy and radiotherapy even in patients with atypical metastatic sites
Shock wave lithotripsy for a renal stone in a tetraplegic patient as a trigger for life-threatening posterior reversible encephalopathy syndrome
Shock wave lithotripsy (SWL) is considered a non-invasive treatment for urinary stones and usually advocated for frail patients with spinal cord injury (SCI). We report a life-threatening complication, called posterior reversible encephalopathy syndrome (PRES), in a tetraplegic person who underwent SWL for a small renal stone. Based on our experience, we recommend performing SWL with caution in SCI patients and in tertiary referral hospitals that can promptly manage similar severe complications
Salicylic Acid Peel Incorporating Triethyl Citrate and Ethyl Linoleate in the Treatment of Moderate Acne: A New Therapeutic Approach.
BACKGROUND:
Acne affects many adolescents. Conventional therapy often results in side effects and poor adherence, and the treatment does not consider the psychological effect of acne on patients, which is comparable with that of disabling diseases.
OBJECTIVES:
To evaluate the efficacy and tolerability of a peel (30% salicylic acid, triethyl citrate and ethyl linoleate) combined with a home therapy with three topical agents (triethyl citrate, ethyl linoleate and salicylic acid 0.5% cream, lotion) in moderate acne of the face.
DESIGN:
Prospective, observational, multicenter, open-label, postmarketing, phase IV study.
METHODS:
Patients were assessed by comparing Global Acne Grading System (GAGS) score and total lesion count from 15 days before the first peel (T-15 ), after four salicylic peels (every 10 ± 2 days (T0 , T10 , T20 , T30 ), and 20 days after of the end of the study (T50 ). This treatment was associated to a home therapy.
RESULTS:
Fifty-three patients completed the study. The average GAGS score fell 49% between T-15 and T50 (p < .001). No patient withdrew for adverse events.
CONCLUSIONS:
This therapy was effective and well-tolerated in all cases. Chemo-exfoliation sessions ensured the continuous monitoring of clinical results and improved patient quality of life
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