Beyond quantum mechanics? Hunting the 'impossible' atoms (Pauli Exclusion Principle violation and spontaneous collapse of the wave function at test)

The development of mathematically complete and consistent models solving the so-called "measurement problem", strongly renewed the interest of the scientific community for the foundations of quantum mechanics, among these the Dynamical Reduction Models posses the unique characteristic to be experimentally testable. In the first part of the paper an upper limit on the reduction rate parameter of such models will be obtained, based on the analysis of the X-ray spectrum emitted by an isolated slab of germanium and measured by the IGEX experiment. The second part of the paper is devoted to present the results of the VIP (Violation of the Pauli exclusion principle) experiment and to describe its recent upgrade. The VIP experiment established a limit on the probability that the Pauli Exclusion Principle (PEP) is violated by electrons, using the very clean method of searching for PEP forbidden atomic transitions in copper

Evolution of the levels of human leukocyte antigen G (HLA-G) in Beninese infant during the first year of life in a malaria endemic area : using latent class analysis

Background: HLA-G, a non-classical HLA class I antigen, is of crucial interest during pregnancy by inhibiting maternal immune response. Its role during infections is discussed, and it has been described that high levels of soluble HLA-G during childhood increase the risk of malaria. To explore more precisely interactions between soluble HLA-G and malaria, latent class analysis was used to test whether distinct sub-populations of children, each with distinctive soluble HLA-G evolutions may suggest the existence of groups presenting variable malaria susceptibility. Method: A study was conducted in Benin from 2010 to 2013 and 165 children were followed from birth to 12 months. Evolution of soluble HLA-G was studied by the latent class method. Results: Three groups of children were identified: one with consistently low levels of soluble HLA-G during follow-up, a second with very high levels and a last intermediate group. In all groups, low birth weight, high number of malaria infections and high exposure to malaria transmission were associated with high level of soluble HLA-G. Placental malaria was not. Presence of soluble HLA-G in cord blood increased the probability of belonging to the highest trajectory. Conclusion: These results, together with previous ones, confirm the important role of HLA-G in the individual susceptibility to malaria. Assaying soluble HLA-G at birth could be a good indicator of newborns more fragile and at risk of infections during childhood

Spontaneously emitted X-rays: an experimental signature of the dynamical reduction models

We present the idea of searching for X-rays as a signature of the mechanism inducing the spontaneous collapse of the wave function. Such a signal is predicted by the continuous spontaneous localization theories, which are solving the "measurement problem" by modifying the Schrodinger equation. We will show some encouraging preliminary results and discuss future plans and strategy.Comment: to be published in Foundation of Physics 201

The effect of spontaneous collapses on neutrino oscillations

We compute the effect of collapse models on neutrino oscillations. The effect of the collapse is to modify the evolution of the `spatial' part of the wave function, which indirectly amounts to a change on the flavor components. In many respects, this phenomenon is similar to neutrino propagation through matter. For the analysis we use the mass proportional CSL model, and perform the calculation to second order perturbation theory. As we will show, the CSL prediction is very small - mainly due to the very small mass of neutrinos - and practically undetectable.Comment: 24 pages, RevTeX. Updated versio

X rays on quantum mechanics: Pauli Exclusion Principle and collapse models at test

In the last decades huge theoretical effort was devoted to the development of consistent theoretical models, aiming to solve the so-called \u201cmeasurement problem\u201d. Among these, the Dynamical Reduction Models possess the unique characteristic to be experimentally testable, thus enabling to set experimental upper bounds on the reduction rate parameter \u3bb characterizing these models. By analysing the X-ray spectrum emitted by an isolated slab of Germanium, we set the most stringent limit on the \u3bb parameter up to date

Underground tests of quantum mechanics. Whispers in the cosmic silence?

By performing X-rays measurements in the "cosmic silence" of the underground laboratory of Gran Sasso, LNGS-INFN, we test a basic principle of quantum mechanics: the Pauli Exclusion Principle (PEP), for electrons. We present the achieved results of the VIP experiment and the ongoing VIP2 measurement aiming to gain two orders of magnitude improvement in testing PEP. We also use a similar experimental technique to search for radiation (X and gamma) predicted by continuous spontaneous localization models, which aim to solve the "measurement problem"

The role of the placenta in the vertical transmission of HIV-1

A transmissão vertical (TV) consiste na principal forma de infecção pelo HIV-1 em menores de 13 anos e estimativas apontam que em 25% dos casos a transmissão tenha ocorrido intraútero. Nessas circunstâncias, o vírus de alguma forma ultrapassa a membrana placentária e chega ao sangue fetal. Esta revisão tem como objetivo realizar uma breve descrição sobre os mecanismos presentes na placenta humana que são capazes de gerar susceptibilidade ou proteção à TV do HIV-1. As células placentárias produzem um enorme grupo de citocinas, quimiocinas, hormônios e receptores que podem contribuir com o desfecho da transmissão do vírus ao concepto. Além disso, a capacidade do vírus de infectar as células placentárias também pode contribuir com a sua transmissão. Entretanto, o mecanismo pelo qual o vírus é capaz de sobrepujar a membrana placentária e as consequências dessa infecção no tecido placentário não estão totalmente elucidados. Dessa forma, novas pesquisas nessa área poderão contribuir com o desenvolvimento de estratégias profiláticas eficazes para redução da TV do HIV-1Vertical transmission (VT) is the main form of infection by HIV-1 in children under 13 years and estimates show that in 25% of cases intrauterine transmission has occurred. Under these circumstances, the virus somehow overcomes the placental membrane and reaches the fetal blood. This review aims to conduct a brief description of the mechanisms present in human placenta that are capable of generating susceptibility or resistance to VT of HIV-1. Placental cells produces a huge group of cytokines, chemokines, hormones and receptors that may contribute to the outcome of virus transmission to the fetus. Moreover, the ability of the virus to infect placental cells can also contribute to its transmission. However, the mechanism by which the virus is able to overcome the placental tissue is not fully elucidated. Thus, further research in this area may contribute to the development of effective preventive strategies to reduce the VT of HIV-

VIP-2 at LNGS: An experiment on the validity of the Pauli Exclusion Principle for electrons

Abstract. We are experimentally investigating possible violations of standard quantum mechanics predictions in the Gran Sasso underground laboratory in Italy. We test with high precision the Pauli Exclusion Principle and the collapse of the wave function (collapse models). We present our method of searching for possible small violations of the Pauli Exclusion Principle (PEP) for electrons, through the search for \u201canomalous\u201d X-ray transitions in copper atoms. These transitions are produced by \u201cnew\u201d electrons (brought inside the copper bar by circulating current) which can have the possibility to undergo Pauli-forbidden transition to the 1s level already occupied by two electrons. We describe the VIP2 (VIolation of the Pauli Exclusion Principle) experimental data taking at the Gran Sasso underground laboratories. The goal of VIP2 is to test the PEP for electrons in agreement with the Messiah-Greenberg superselection rule with unprecedented accuracy, down to a limit in the probability that PEP is violated at the level of 10^ 1231. We show preliminary experimental results and discuss implications of a possible violation

MiRNA-Mediated Control of HLA-G Expression and Function

HLA-G is a non-classical HLA class-Ib molecule expressed mainly by the extravillous cytotrophoblasts (EVT) of the placenta. The expression of HLA-G on these fetal cells protects the EVT cells from immune rejection and is therefore important for a healthy pregnancy. The mechanisms controlling HLA-G expression are largely unknown. Here we demonstrate that miR-148a and miR-152 down-regulate HLA-G expression by binding its 3′UTR and that this down-regulation of HLA-G affects LILRB1 recognition and consequently, abolishes the LILRB1-mediated inhibition of NK cell killing. We further demonstrate that the C/G polymorphism at position +3142 of HLA-G 3′UTR has no effect on the miRNA targeting of HLA-G. We show that in the placenta both miR-148a and miR-152 miRNAs are expressed at relatively low levels, compared to other healthy tissues, and that the mRNA levels of HLA-G are particularly high and we therefore suggest that this might enable the tissue specific expression of HLA-G