Stray Magnetic Field Compensation with a Scalar Atomic Magnetometer

We describe a system for the compensation of time-dependent stray magnetic fields using a dual channel scalar magnetometer based on non-linear Faraday rotation in synchronously optically pumped Cs vapour. We detail the active control strategy, with an emphasis on the electronic circuitry, based on a simple phase-locked-loop integrated circuit. The performance and limits of the system developed are tested and discussed. The system was applied to significantly improve the detection of free induction decay signals from protons of remotely magnetized water precessing in an ultra-low magnetic field.Comment: 8 pages, 6 figures, 31 refs, v2 (with minor improvements) appearing in Rev.Sc.Instr. June 201

Colorectal cancer promoter methylation alteration affects the expression of glutamate ionotropic receptor AMPA type subunit 4 alternative isoforms potentially relevant in colon tissue

DNA methylation alterations are early events during tumourigenesis, affecting genes involved in the crosstalk between cells and surroundings in colorectal cancer (CRC). Among these genes, GRIA4, Glutamate Ionotropic Receptor AMPA Type Subunit 4, displays hypermethylation in the promoter region, and is an early diagnostic biomarker. It is well known that methylation can also affect alternative transcription. The purpose of this study is to evaluate the expression, at transcript and protein level, of GRIA4 main isoforms (the canonical one and a short variant) in 23 CRC and matched normal samples, of which we previously verified the methylation status. We further predicted miRNA/transcript target interactions as a possible post-transcriptional regulation using bioinformatics tools. As expected, downregulation of both variants has been observed in tumours. Interestingly, in contrast to what observed at transcriptional level, the GluR4 protein short isoform displayed higher expression than the canonical one either in normal or tumoural tissues. This may be explained by miRNA specifically targeting the canonical isoform. Our study is the first one that shows the expression of both isoforms in colon tissues. To note, the evident expression of the short isoform suggests a functional role in intestinal cell biology

A distinguishing gene signature shared by tumor-infiltrating Tie2-expressing monocytes, blood "resident" monocytes, and embryonic macrophages suggests common functions and developmental relationships

We previously showed that Tie2-expressing monocytes (TEMs) have nonredundant proangiogenic activity in tumors. Here, we compared the gene expression profile of tumor-infiltrating TEMs with that of tumor-associated macrophages (TAMs), spleen-derived Gr1(+)Cd11b(+) neutrophils/myeloid-derived suppressor cells, circulating "inflammatory" and "resident" monocytes, and tumor-derived endothelial cells (ECs) by quantitative polymerase chain reaction-based gene arrays. TEMs sharply differed from ECs and Gr1(+)Cd11b(+) cells but were highly related to TAMs. Nevertheless, several genes were differentially expressed between TEMs and TAMs, highlighting a TEM signature consistent with enhanced proangiogenic/tissue-remodeling activity and lower proinflammatory activity. We validated these findings in models of oncogenesis and transgenic mice expressing a microRNA-regulated Tie2-GFP reporter. Remarkably, resident monocytes and TEMs on one hand, and inflammatory monocytes and TAMs on the other hand, expressed coordinated gene expression profiles, suggesting that the 2 blood monocyte subsets are committed to distinct extravascular fates in the tumor microenvironment. We further showed that a prominent proportion of embryonic/fetal macrophages, which participate in tissue morphogenesis, expressed distinguishing TEM genes. It is tempting to speculate that Tie2(+) embryonic/fetal macrophages, resident blood monocytes, and tumor-infiltrating TEMs represent distinct developmental stages of a TEM lineage committed to execute physiologic proangiogenic and tissue-remodeling programs, which can be co-opted by tumors

現地観測に基づく河川流の乱流特性に関する研究

博士（工学）神戸大

All-optical magnetometry for NMR detection in micro-Tesla field and unshielded environment

4reservedAn all-optical atomic magnetometer is used to detect a proton free-precession signal from a water sample polarized in a 0.7 T field and remotely analyzed in a 4 lT field. Nuclear spins are manipulated either by p=2 pulses or by non-adiabatic rotation. The magnetometer operates at room temperature, in an unshielded environment and has a dual-channel sensor for differential measurements.mixedG. BEVILACQUA; V. BIANCALANA; Y. DANCHEVA; L. MOIBevilacqua, Giuseppe; Biancalana, Valerio; Dancheva, Yordanka; Moi, Luig

Optical atomic magnetometry for ultra-low-field NMR detection

This chapter deals with detection of NMR signals in the ultra-low-field (ULF) regime, by means of optical atomic magnetometers. A general introduction is provided about specific NMR features occurring when nuclei precess in micro-Tesla fields, or weaker. The advantages of detecting the NMR signal by means of an optical atomic magnetometer are here preliminarly discussed. A further general introduction is provided about basic ideas and recent progresses in optical atomic magnetometry. A section is devoted to the detailed presentation of an example of dual-channel atomic magne- tometer which was used to detect the signal produced by protons of a remotely polarized water sample in an unshielded environment, taking advantage of its differential nature. Results reported in a wide set of similar experiments are then discussed in a general synthesis of the interdisciplinary activity performed on the main subject of this work. Emphasis is given to progresses in ULF imaging, in microfluidic, in setups designed for zero-field and near-zero-field NMR detection. The non-conventional NMR detection schemes discussed in this chapter are in some cases prof- itably coupled with non-conventional methods for sample polarization. Some experiments devoted to non-conventional preparation of the nuclear spin state are considered and briefly discussed, as well

An efficient photo-atom source

We show that it is possible to obtain a very efficient photo-atom source, whose atom flux is regulated by light. The atom release is due to the recently observed light-induced atom desorption effect from silane coated cells. We report the results obtained at room temperature with rubidium in a double body cell coated with (poly)dimethyl-siloxane. This kind of photo-atom source can be immediately extended to other alkali atoms, namely sodium, potassium and cesium. Possible applications are discussed

Nonthermal light-induced atom desorption

A new effect, observed for the first time by A. Gozzini et al. with sodium, is reported where huge Rb vapor density variations are observed when silane coated cells are illuminated by weak light. The effect is due to light-induced atom desorption from the coated cell walls and it is nonthermal as the triggering light power density may be very weak. The effect depends, among others, on the light wavelength and intensity