7,213 research outputs found
Quick and sensitive determination of gene expression of fatty acid synthase in vitro by using real-time polymerase chain reaction amplification (PCR)
Obesity results from an imbalance between energy intake and energy expenditure, which leads to a pathological accumulation of adipose tissue, but the underlying mechanism at gene level, is far from being elucidated. The objective of this study was to investigate the correlation between mRNA express from fatty acid synthase (FAS) with a different glucose level in primary adipocytes by real-time polymerase chain reaction amplification (PCR), which can aid in the understanding of the mechanism of obesity in vitro. By using the following formula, this study was able to quantify the mRNA expression of FAS of unknown samples: Y = -3.156X + 41.21 (Y = threshold cycle, X = log starting quantity). The high concentrations of glucose group significantly improved the mRNA expression of FAS (P < 0.01) rather than 0.25 and 0% concentrations of glucose. These results provide significant data that confirm an association between different glucose level and FAS expression in preadipocytes. The glucose concentration of the high group substantially augmented the mRNA expression of FAS.Key words: Expression, fatty acid synthase, lipid deposition, real-time polymerase chain reaction amplification (PCR)
Mobile Communication Signatures of Unemployment
The mapping of populations socio-economic well-being is highly constrained by
the logistics of censuses and surveys. Consequently, spatially detailed changes
across scales of days, weeks, or months, or even year to year, are difficult to
assess; thus the speed of which policies can be designed and evaluated is
limited. However, recent studies have shown the value of mobile phone data as
an enabling methodology for demographic modeling and measurement. In this work,
we investigate whether indicators extracted from mobile phone usage can reveal
information about the socio-economical status of microregions such as districts
(i.e., average spatial resolution < 2.7km). For this we examine anonymized
mobile phone metadata combined with beneficiaries records from unemployment
benefit program. We find that aggregated activity, social, and mobility
patterns strongly correlate with unemployment. Furthermore, we construct a
simple model to produce accurate reconstruction of district level unemployment
from their mobile communication patterns alone. Our results suggest that
reliable and cost-effective economical indicators could be built based on
passively collected and anonymized mobile phone data. With similar data being
collected every day by telecommunication services across the world,
survey-based methods of measuring community socioeconomic status could
potentially be augmented or replaced by such passive sensing methods in the
future
A proposal for selective resuscitation of adult cardiac arrest patients in a pandemic
Allocation of limited resources in pandemics begs for ethical guidance. The issue of ventilator allocation in pandemics has been reviewed by many medical ethicists, but as localities activate crisis standards of care, and health care workers are infected from patient exposure, the decision to pursue cardiopulmonary resuscitation (CPR) must also be examined to better balance the increased risks to healthcare personnel with the very low resuscitation rates of patients infected with coronavirus disease 2019 (COVID‐19). A crisis standard of care that is equitable, transparent, and mindful of both human and physical resources will lessen the impact on society in this era of COVID‐19. This paper builds on previous work of ventilator allocation in pandemic crises to propose a literature‐based, justice‐informed ethical framework for selecting treatment options for CPR. The pandemic affects regions differently over time, so these suggested guidelines may require adaptation to local practice variations.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/156457/3/emp212096_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156457/2/emp212096.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156457/1/emp212096-sup-0001-Appendix.pd
Microbial catabolic activities are naturally selected by metabolic energy harvest rate
The fundamental trade-off between yield and rate of energy harvest per unit of substrate has been largely discussed as a main characteristic for microbial established cooperation or competition. In this study, this point is addressed by developing a generalized model that simulates competition between existing and not experimentally reported microbial catabolic activities defined only based on well-known biochemical pathways. No specific microbial physiological adaptations are considered, growth yield is calculated coupled to catabolism energetics and a common maximum biomass-specific catabolism rate (expressed as electron transfer rate) is assumed for all microbial groups. Under this approach, successful microbial metabolisms are predicted in line with experimental observations under the hypothesis of maximum energy harvest rate. Two microbial ecosystems, typically found in wastewater treatment plants, are simulated, namely: (i) the anaerobic fermentation of glucose and (ii) the oxidation and reduction of nitrogen under aerobic autotrophic (nitrification) and anoxic heterotrophic and autotrophic (denitrification) conditions. The experimentally observed cross feeding in glucose fermentation, through multiple intermediate fermentation pathways, towards ultimately methane and carbon dioxide is predicted. Analogously, two-stage nitrification (by ammonium and nitrite oxidizers) is predicted as prevailing over nitrification in one stage. Conversely, denitrification is predicted in one stage (by denitrifiers) as well as anammox (anaerobic ammonium oxidation). The model results suggest that these observations are a direct consequence of the different energy yields per electron transferred at the different steps of the pathways. Overall, our results theoretically support the hypothesis that successful microbial catabolic activities are selected by an overall maximum energy harvest rate
Random Walks on Stochastic Temporal Networks
In the study of dynamical processes on networks, there has been intense focus
on network structure -- i.e., the arrangement of edges and their associated
weights -- but the effects of the temporal patterns of edges remains poorly
understood. In this chapter, we develop a mathematical framework for random
walks on temporal networks using an approach that provides a compromise between
abstract but unrealistic models and data-driven but non-mathematical
approaches. To do this, we introduce a stochastic model for temporal networks
in which we summarize the temporal and structural organization of a system
using a matrix of waiting-time distributions. We show that random walks on
stochastic temporal networks can be described exactly by an
integro-differential master equation and derive an analytical expression for
its asymptotic steady state. We also discuss how our work might be useful to
help build centrality measures for temporal networks.Comment: Chapter in Temporal Networks (Petter Holme and Jari Saramaki
editors). Springer. Berlin, Heidelberg 2013. The book chapter contains minor
corrections and modifications. This chapter is based on arXiv:1112.3324,
which contains additional calculations and numerical simulation
On-demand semiconductor single-photon source with near-unity indistinguishability
Single photon sources based on semiconductor quantum dots offer distinct
advantages for quantum information, including a scalable solid-state platform,
ultrabrightness, and interconnectivity with matter qubits. A key prerequisite
for their use in optical quantum computing and solid-state networks is a high
level of efficiency and indistinguishability. Pulsed resonance fluorescence
(RF) has been anticipated as the optimum condition for the deterministic
generation of high-quality photons with vanishing effects of dephasing. Here,
we generate pulsed RF single photons on demand from a single,
microcavity-embedded quantum dot under s-shell excitation with 3-ps laser
pulses. The pi-pulse excited RF photons have less than 0.3% background
contributions and a vanishing two-photon emission probability.
Non-postselective Hong-Ou-Mandel interference between two successively emitted
photons is observed with a visibility of 0.97(2), comparable to trapped atoms
and ions. Two single photons are further used to implement a high-fidelity
quantum controlled-NOT gate.Comment: 11 pages, 11 figure
How early can myocardial iron overload occur in Beta thalassemia major?
BACKGROUND: Myocardial siderosis is the most common cause of death in patients with beta thalassemia major(TM). This study aimed at investigating the occurrence, prevalence and severity of cardiac iron overload in a young Chinese population with beta TM.
METHODS AND RESULTS: We analyzed T2* cardiac magnetic resonance (CMR), left ventricular ejection fraction (LVEF) and serum ferritin (SF) in 201 beta TM patients. The median age was 9 years old. Patients received an average of 13 units of blood per year. The median SF level was 4536 ng/ml and 165 patients (82.1%) had SF>2500 ng/ml. Myocardial iron overload was detected in 68 patients (33.8%) and severe myocardial iron overload was detected in 26 patients (12.6%). Twenty-two patients ≤10 years old had myocardial iron overload, three of whom were only 6 years old. No myocardial iron overload was detected under the age of 6 years. Median LVEF was 64% (measured by CMR in 175 patients). Five of 6 patients with a LVEF<56% and 8 of 10 patients with cardiac disease had myocardial iron overload.
CONCLUSIONS: The TM patients under follow-up at this regional centre in China patients are younger than other reported cohorts, more poorly-chelated, and have a high burden of iron overload. Myocardial siderosis occurred in patients younger than previously reported, and was strongly associated with impaired LVEF and cardiac disease. For such poorly-chelated TM patients, our data shows that the first assessment of cardiac T2* should be performed as early as 6 years old
Rings in the Solar System: a short review
Rings are ubiquitous around giant planets in our Solar System. They evolve
jointly with the nearby satellite system. They could form either during the
giant planet formation process or much later, as a result of large scale
dynamical instabilities either in the local satellite system, or at the
planetary scale. We review here the main characteristics of rings in our solar
system, and discuss their main evolution processes and possible origin. We also
discuss the recent discovery of rings around small bodies.Comment: Accepted for the Handbook of Exoplanet
The Effects of Serotonin Receptor Antagonists on Contraction and Relaxation Responses Induced by Electrical Stimulation in the Rat Small Intestine
Background: The main source of 5-HT in body is in enterchromafin cells of intestine, different studies mentioned different roles for endogenous 5-HT and receptors involved and it is not clearified the mechanism of action of endogenous 5-HT.
Objectives: To study the role of endogenous 5-HT on modulation of contraction and relaxation responses induced by electrical field stimulation (EFS) in different regions of the rat intestine.
Materials and Methods: Segments taken from the rat duodenum, jejunum, mid and terminal ileum were vertically mounted, connected to a transducer and exposed to EFS with different frequencies in the absence and presence of various inhibitors of enteric mediators i. e. specific 5-HT receptor antagonists.
Results: EFS-induced responses were sensitive to TTX and partly to atropine, indicating a major neuronal involvement and a cholinergic system. Pre-treatment with WAY100635 (a 5-HT1A receptor antagonist) and granisetron up to 10.0 µM, GR113808 (a 5-HT4 receptor antagonist), methysergide and ritanserin up to 1.0 µM, failed to modify responses to EFS inall examined tissues. In the presence of SB258585 1.0 µM (a 5-HT6 receptor antagonist) there was a trend to enhance contraction in the proximal part of the intestine and reduce contraction in the distal part. Pre-treatment with SB269970A 1.0 µM (5-HT7 receptor antagonist) induced a greater contractile response to EFS at 0.4 Hz only in the duodenum.
Conclusions: The application of 5-HT1A, 5-HT2, 5-HT3, 5-HT4, 5-HT6 and 5-HT7 receptor antagonists, applied at concentrations lower than 1.0 µM did not modify the EFS-induced contraction and relaxation responses, whichsuggests the unlikely involvement of endogenous 5-HT in mediating responses to EFS in the described test conditions.
Keywords: Electric Stimulation Therapy; Serotonin 5-HT1 Receptor Antagonists; Intestine, Smal
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