Transcriptional regulation of prostate kallikrein-like genes by androgen.

Using gene-specific synthetic oligonucleotides the expression and regulation of kallikrein-like genes in the human prostatic cancer cell line LNCaP were studied. Prostate-specific antigen (PSA) and human glandular kallikrein (hGK-1) together constitute a subfamily of serine proteases exclusively produced in the human prostate. RNA analysis revealed that both genes are expressed in LNCaP cells with PSA basal levels being 2-fold higher than hGK-1 levels. Both mRNAs are induced over a period of 24 h in the presence of 3.3 nM of the synthetic androgen mibolerone. Stimulation of PSA RNA is about 5- fold,whereas hGK-1 stimulation is less pronounced. Nuclear run-on analysis revealed that androgen induction of kallikrein-like genes in LNCaP cells is a rapid event (c3 h) occurring at the level of transcription initiation. Treatment of cells with cycloheximide demonstrates that, while PSA/hGK-1 basal transcription strictly depends on continuous protein synthesis, transcriptional induction by androgen does not. This suggests the direct involvement of the androgen receptor in the induction process independent of additional labile protein factors necessary for kallikrein basal transcription. A binding motif is present in the PSA and hGK-1 promoters, closely resembling the consensus sequence for steroidresponsive elements. The androgen antagonist cyproterone acetate was also able to stimulate transcription of kallikrein-like genes in LNCaP cells. In contrast, androgen-dependent transcriptional suppression of the protooncogene c-myc was strongly counteracted by cyproterone acetate. Thus, antiandrogens act differentially on androgen-regulated prostate-specific (PSA, hGK-1) and growthrelated (c-myc) gene expression in LNCaP cells

Treating critically ill patients with probiotics: Beneficial or dangerous?

Probiotic bacteria are live microorganisms which confer to health benefits of the host. They help to maintain the integrity of the intestinal barrier function by modulating the mucosal and systemic immune response of the host. These bacteria have proven their beneficial effect in several conditions of ulcerative colitis. More recently probiotics/synbiotics have been included in the treatment of critically ill patients. However to date it remains uncertain whether probiotics/synbiotics are beneficial or even dangerous to the clinical outcome of this patient group. This article reviews the current evidence of the use of bacteria in critically ill patients in intensive care settings

Nanomateriais e a interface entre nanotecnologia e ambiente

Nanomaterials are the main products of nanotechnology. In this paper we describe some of these nanomaterials, particularly Carbon based systems, their properties, manipulation strategies and applications. History of nanoparticles, as well as the complexity in defining nanomaterials, necessary for regulation and assessment of impacts on society, are also addressed.Nanomateriais são os principais produtos das nanotecnologias. Nesse artigo são descritos alguns desses nanomateriais, em particular os compostos de Carbono, suas propriedades, estratégias de manipulação e aplicações. Discute-se também a história das nanopartículas e a complexidade na classificação desses materiais, necessária para sua regulamentação e avaliação de impactos na sociedade

Linguagens Perdidas De Divulgação Científica: Simulacros E Artesanatos

Esse artigo propõe um resgate da história de uma prática que foi paulatinamente sendo suplantada pelas novas tecnologias de linguagem em divulgação científica. É um manifesto em forma de crônica, um registro, para propor uma reavaliação dos kits de experimentação científica, que alcançaram talvez o auge de sua popularidade nos anos 70 do século passado.15248-56Estudos Urbano

Two clouds still obscure the reputation of Lord Kelvin

Lord Kelvin is considered one of the most important physicists of the nineteenth century. With multiple talents and a public man, he is the author of famous aphorisms, but many phrases attributed to him are not more than urban legends. One of the most known is that there are only two little clouds in the sky of physics and many variations, alluding the belief of completeness in physics at the beginning of the last century. The two little clouds are nothing else than the theory of relativity and quantum mechanics, the two pillars of modern physics. In opposition to what is often propagated, Lord Kelvin seemed to be quite aware of the dead end of classical physics at that time and gave a clear indication to the newcomers of the paths to be followed.Lorde Kelvin é considerado um dos mais importantes físicos do século XIX. Talento multifacetado e homem público é autor de aforismos famosos, mas muitas frases a ele atribuídas não passam de lendas urbanas. Uma das mais famosas é a de existem apenas duas nuvenzinhas no céu da física, e suas variantes, aludindo à crença de completude da física no início do século passado. As duas nuvenzinhas nada mais são do que a teoria da relatividade e a mecânica quântica, os dois pilares da física moderna. Ao contrário do que muitos propagam, Lorde Kelvin na verdade parecia estar bem ciente do impasse da física clássica na época e deixou para os seus sucessores uma indicação clara de que rumos deveriam ser seguidos.50951

Lord of the Rings: A Kinematic Distance to Circinus X-1 from a Giant X-Ray Light Echo

Circinus X-1 exhibited a bright X-ray flare in late 2013. Follow-up observations with Chandra and XMM-Newton from 40 to 80 days after the flare reveal a bright X-ray light echo in the form of four well-defined rings with radii from 5 to 13 arcminutes, growing in radius with time. The large fluence of the flare and the large column density of interstellar dust towards Circinus X-1 make this the largest and brightest set of rings from an X-ray light echo observed to date. By deconvolving the radial intensity profile of the echo with the MAXI X-ray lightcurve of the flare we reconstruct the dust distribution towards Circinus X-1 into four distinct dust concentrations. By comparing the peak in scattering intensity with the peak intensity in CO maps of molecular clouds from the Mopra Southern Galactic Plane CO Survey we identify the two innermost rings with clouds at radial velocity ~ -74 km/s and ~ -81 km/s, respectively. We identify a prominent band of foreground photoelectric absorption with a lane of CO gas at ~ -32 km/s. From the association of the rings with individual CO clouds we determine the kinematic distance to Circinus X-1 to be $D_{Cir X-1} = 9.4^{+0.8}_{-1.0}$ kpc. This distance rules out earlier claims of a distance around 4 kpc, implies that Circinus X-1 is a frequent super-Eddington source, and places a lower limit of $\Gamma \gtrsim 22$ on the Lorentz factor and an upper limit of $\theta_{jet} \lesssim 3^{\circ}$ on the jet viewing angle.Comment: 20 pages, 21 figures, Astrophysical Journal, in prin

Robust signatures in the current-voltage characteristics of DNA molecules oriented between two graphene nanoribbon electrodes

In this work we numerically calculate the electric current through three kinds of DNA sequences (telomeric, \lambda-DNA, and p53-DNA) described by different heuristic models. A bias voltage is applied between two zig-zag edged graphene contacts attached to the DNA segments, while a gate terminal modulates the conductance of the molecule. The calculation of current is performed by integrating the transmission function (calculated using the lattice Green's function) over the range of energies allowed by the chemical potentials. We show that a telomeric DNA sequence, when treated as a quantum wire in the fully coherent low-temperature regime, works as an excellent semiconductor. Clear steps are apparent in the current-voltage curves of telomeric sequences and are present independent of lengths and sequence initialisation at the contacts. The current-voltage curves suggest the existence of stepped structures independent of length and sequencing initialisation at the contacts. We also find that the molecule-electrode coupling can drastically influence the magnitude of the current. The difference between telomeric DNA and other DNA, such as \lambda-DNA and DNA for the tumour suppressor p53, is particularly visible in the length dependence of the current

An Exactly Solvable Model of N Coupled Luttinger Chains

We calculate the exact Green function of a special model of N coupled Luttinger chains with arbitrary interchain hopping t_{perp}. The model is exactly solvable via bosonization if the interchain interaction does not fall off in the direction perpendicular to the chains. For any finite N we find Luttinger liquid behavior and explicitly calculate the anomalous dimension gamma^(N). However, the Luttinger liquid state does not preclude coherent interchain hopping. We also show that gamma^(N) -> 0 for N -> infinity, so that in the limit of infinitely many chains we obtain a Fermi liquid.Comment: accepted for publication in Phys. Rev.

Visible-to-telecom quantum frequency conversion of light from a single quantum emitter

Quantum frequency conversion (QFC), a nonlinear optical process in which the frequency of a quantum light field is altered while conserving its non-classical correlations, was first demonstrated 20 years ago. Meanwhile, it is considered an essential tool for the implementation of quantum repeaters since it allows for interfacing quantum memories with telecom-wavelength photons as quantum information carriers. Here we demonstrate efficient (>30%) QFC of visible single photons (711 nm) emitted by a quantum dot (QD) to a telecom wavelength (1,313 nm). Analysis of the first and second-order coherence before and after wavelength conversion clearly proves that important properties, such as the coherence time and photon antibunching, are fully conserved during the frequency translation process. Our findings underline the great potential of single photon sources on demand in combination with QFC as a promising technique for quantum repeater schemes.Comment: 11 pages, 4 figure