Nitrogen vacancy diamonds have emerged as sensitive solid-state magnetic field sensors capable of producing diffraction limited and sub-diffraction field images. Here, for the first time, to our knowledge, we extend those measurements to high-speed imaging, which can be readily applied to analyze currents and magnetic field dynamics in circuits on a microscopic scale. To overcome detector acquisition rate limitations, we designed an optical streaking nitrogen vacancy microscope to acquire two-dimensional spatiotemporal kymograms. We demonstrate magnetic field wave imaging with micro-scale spatial extent and ~400 μs temporal resolution. In validating this system, we detected magnetic fields down to 10 μT for 40 Hz magnetic fields using single-shot imaging and captured the spatial transit of an electromagnetic needle at streak rates as high as 110 μm/ms. This design has the capability to be readily extended to full 3D video acquisition by utilizing compressed sensing techniques and a potential for further improvement of spatial resolution, acquisition speed, and sensitivity. The device opens opportunities to many potential applications where transient magnetic events can be isolated to a single spatial axis, such as acquiring spatially propagating action potentials for brain imaging and remotely interrogating integrated circuits.

• Publikační typ
• časopisecké články MeSH

The primary goal of this work was to distinguish between soil pollution from long-range and local transport of atmospheric pollutants using soil magnetometry supported by geochemical analyses. The study area was located in the Izery region of Poland (within the "Black Triangle" region, which is the nickname for one of Europe's most polluted areas, where Germany, Poland and the Czech Republic meet). One site of the study area was situated in the Forest Glade and was exposed to anthropogenic pollution from a former glasswork. The second site of the study area was located on a neighboring hill (Granicznik) of which the western, northwestern and southwestern parts of the slope were exposed to the long-range transport of atmospheric pollutants from the Czech Republic, Germany and Poland. Magnetic susceptibility was measured on the soil surface and in the soil samples using a MS2 Bartington meter equipped with MS2D and MS2C sensors, respectively. Using soil magnetometry, it was possible to discriminate between long-range transport of atmospheric pollutants and anthropogenic pollution related to the former glasswork located in the Forest Glade. Additionally, using MS2C measurements and geochemical analyses of sixteen trace elements, it was possible to discriminate between natural and anthropogenic origins of a soil magnetic susceptibility signal. Our results indicate that the Forest Glade site is characterized by relatively significant anthropogenic translocation of topsoil horizons, presence of artefacts, more hot spots, very high spatial variability, and higher nugget effect than on the Granicznik Hill.

• Klíčová slova
• Geostatistics, Long-range transport of atmospheric pollutants, Soil magnetometry, Soil pollution, Trace elements,
• MeSH
• látky znečišťující půdu analýza   MeSH
• látky znečišťující vzduch analýza   MeSH
• magnetometrie * MeSH
• monitorování životního prostředí metody   statistika a číselné údaje   MeSH
• půda chemie   MeSH
• stopové prvky analýza   MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Česká republika MeSH
• Německo MeSH
• Polsko MeSH
• Názvy látek
• látky znečišťující půdu MeSH
• látky znečišťující vzduch MeSH
• půda MeSH
• stopové prvky MeSH

Diamond magnetometry can provide new insights on the production of free radicals inside live cells due to its high sensitivity and spatial resolution. However, the measurements often lack intracellular context for the recorded signal. In this paper, the possible use of single-particle tracking and trajectory analysis of fluorescent nanodiamonds (FNDs) to bridge that gap is explored. It starts with simulating a set of different possible scenarios of a particle's movement, reflecting different modes of motion, degrees of confinement, as well as shapes and sizes of that confinement. Then, the insights from the analysis of the simulated trajectories are applied to describe the movement of FNDs in glycerol solutions. It is shown that the measurements are in good agreement with the previously reported findings and that trajectory analysis yields meaningful results, when FNDs are tracked in a simple environment. Then the much more complex situation of FNDs moving inside a live cell is focused. The behavior of the particles after different incubation times is analyzed, and the possible intracellular localization of FNDs is deducted from their trajectories. Finally, this approach is combined with long-term magnetometry methods to obtain maps of the spin relaxation dynamics (or T1) in live cells, as FNDs move through the cytosol.

• Klíčová slova
• fluorescent nanodiamonds, free radicals, magnetometry, single-particle tracking,
• MeSH
• diamant MeSH
• fluorescenční barviva MeSH
• glycerol MeSH
• nanodiamanty * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• diamant MeSH
• fluorescenční barviva MeSH
• glycerol MeSH
• nanodiamanty * MeSH

Mucosal surfaces are the first mechanical barrier preventing the entry of foreign particles into the organism. The study addresses the detection and analysis of metal-based solid particles in cytological mucus samples from the surface of human hypertrophic tissue in the inferior nasal turbinates in patients diagnosed with chronic rhinitis. Solid particles were characterized by scanning electron microscopy and Raman microspectroscopy; all the biological samples were also subjected to vibration magnetometry. Since the upper airways are the first part of the respiratory tract, which is exposed to inhaled particles, it can be assumed that inhaled particles may be partially deposited in this region. Scanning electron microscopy revealed the presence of metal-based solid particles/clusters in the majority of the analysed cytological mucus samples and also in hypertrophic tissues; in all groups, the particles were of submicron size. Raman microspectroscopy detected the presence of particles/clusters based on amorphous carbon, graphite, calcium carbonate, anatase and barite only in the hypertrophic tissue. The obtained results show that the composition of some of the solid particles (i.e. Ba, Zn, Fe and Ti) detected in the mucus from the surface of the hypertrophic tissues resembled the particles found in the hypertrophic tissue itself. It can be assumed that after the capture of the inhaled particles by the mucus, they penetrate into the deeper layers of tissue.

• Klíčová slova
• Inflammatory tissue, Inhaled metal particles, Mucus, Raman microspectroscopy, Scanning electron microscopy, Vibration magnetometry,
• MeSH
• hlen MeSH
• kovy MeSH
• lidé MeSH
• mikroskopie elektronová rastrovací MeSH
• nosní skořepy * MeSH
• rýma * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• kovy MeSH

The archaeological site of Březnice (Czechia) represents one of the large settlements of the Late Bronze Age (Ha A2/B1, 14C: 1124-976 BC) in Bohemia. The site became known mainly for a high number of so-called 'trenches', oblong pit features (breadth around 1 m, length 4-7 m), remarkable not only for their specific shape but also for their contents (unusual amounts of pottery, daub, loom weights and other finds, often with traces of a strong fire). In 2018-20, a research project focusing on the study of the site was realized. Magnetometer survey became an integral part of the project since it represented a way to obtain an overall image of the site. A 5-channel fluxgate gradiometer from Sensys (Germany) was used; the vertical gradient of the Z component of the Earth magnetic field was measured. In total, the survey covered an area of over 17 hectares and included over 1.8 million measurements. Profiles were orientated from east to west and data taken bidirectionally (alternate lines in opposite directions), in a 0.5 × 0.2 m grid. The site is extraordinary due to the fact that all archaeological features discovered so far belong to a single archaeological period (Late Bronze Age). This makes the acquired data set exceptional. It can be further used by archaeologists and geophysicists, both to create alternative models of the dynamics of prehistoric settlements and to better understand the nature and interpretive possibilities of the magnetometer data in archaeology as such.

• Klíčová slova
• Bronze Age settlement site, House burning, Intra-site patterning, Magnetometry, Prehistoric homestead clusters, Source data,
• Publikační typ
• časopisecké články MeSH

We investigated the heating abilities of magnetic nanoparticles (MNPs) in a high-frequency magnetic field (MF) as a function of surface coating and size. The cobalt ferrite MNPs were obtained by a hydrothermal method in a water-oleic acid-ethanol system, yielding MNPs with mean diameter of about 5 nm, functionalized with the oleic acid. By applying another cycle of hydrothermal synthesis, we obtained MNPs with about one nm larger diameter. In the next step, the oleic acid was exchanged for 11-maleimidoundecanoic acid or 11-(furfurylureido)undecanoic acid. For the heating experiments, all samples were dispersed in the same solvent (dichloroethane) in the same concentration and the heating performance was studied in a broad interval of MF frequencies (346-782 kHz). The obtained results enabled us to disentangle the impact of the hydrodynamic, structural, and magnetic parameters on the overall heating capabilities. We also demonstrated that the specific power absorption does not show a monotonous trend within the series in the investigated interval of temperatures, pointing to temperature-dependent competition of the Brownian and Néel contributions in heat release.

• Klíčová slova
• effective magnetic anisotropy, magnetic fluid hyperthermia, magnetic nanoparticles, specific power absorption, squid magnetometry, surface coating,
• Publikační typ
• časopisecké články MeSH

Free radicals are crucial indicators for stress and appear in all kinds of pathogenic conditions, including cancer, cardiovascular diseases, and infection. However, they are difficult to detect due to their reactivity and low abundance. We use relaxometry for the detection of radicals with subcellular resolution. This method is based on a fluorescent defect in a diamond, which changes its optical properties on the basis of the magnetic surroundings. This technique allows nanoscale MRI with unprecedented sensitivity and spatial resolution. Recently, this technique was used inside living cells from a cell line. Cell lines differ in terms of endocytic capability and radical production from primary cells derived from patients. Here we provide the first measurements of phagocytic radical production by the NADPH oxidase (NOX2) in primary dendritic cells from healthy donors. The radical production of these cells differs greatly between donors. We investigated the cell response to stimulation or inhibition.

• Klíčová slova
• NV centers, magnetometry, nanodiamonds, relaxometry measurements (T1),
• MeSH
• dendritické buňky MeSH
• diamant MeSH
• lidé MeSH
• magnetismus MeSH
• nanodiamanty * chemie   MeSH
• volné radikály MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• diamant MeSH
• nanodiamanty * MeSH
• volné radikály MeSH

We reanalysed the role of superparamagnetic magnetite clusters observed in a pigeon's upper beak to decide if this matter can be a component of some sort of pigeon magnetometer for Earth orientation. We investigated the mutual interaction of the magnetite clusters induced by the geomagnetic field. The force sensitivity of the hypothetical magnetometer in a pigeon's upper beak was estimated considering the previously presented threshold magnetic sensitivity of pigeons, measured in electrophysiological and behavioural investigations. The typical intercluster magnetic force seems to be 10(-19)N well above the threshold magnetic sensitivity. To strengthen our results, we measured the magnetic susceptibility of superparamagnetic magnetite using a vibrating sample magnetometer. Finally we performed theoretical kinematic analysis of the motion of magnetite clusters in cell plasma. The results indicate that magnetite clusters, constituted by superparamagnetic nanoparticles and observed in a pigeon's upper beak, may not be a component of a measuring system providing the magnetic map.

• MeSH
• biologické modely * MeSH
• biomechanika MeSH
• Columbidae anatomie a histologie   metabolismus   fyziologie   MeSH
• magnetické jevy * MeSH
• magnetometrie * MeSH
• migrace zvířat fyziologie   MeSH
• orientace fyziologie   MeSH
• oxid železnato-železitý metabolismus   MeSH
• zobák metabolismus   fyziologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• oxid železnato-železitý MeSH

The long-dreamed-of capability of monitoring the molecular machinery in living systems has not been realized yet, mainly due to the technical limitations of current sensing technologies. However, recently emerging quantum sensors are showing great promise for molecular detection and imaging. One of such sensing qubits is the nitrogen-vacancy (NV) center, a photoluminescent impurity in a diamond lattice with unique room-temperature optical and spin properties. This atomic-sized quantum emitter has the ability to quantitatively measure nanoscale electromagnetic fields via optical means at ambient conditions. Moreover, the unlimited photostability of NV centers, combined with the excellent diamond biocompatibility and the possibility of diamond nanoparticles internalization into the living cells, makes NV-based sensors one of the most promising and versatile platforms for various life-science applications. In this review, we will summarize the latest developments of NV-based quantum sensing with a focus on biomedical applications, including measurements of magnetic biomaterials, intracellular temperature, localized physiological species, action potentials, and electronic and nuclear spins. We will also outline the main unresolved challenges and provide future perspectives of many promising aspects of NV-based bio-sensing.

• Klíčová slova
• bio-sensing, diamond, electronic and nuclear spin sensing, magnetometry, nitrogen−vacancy center, quantum sensing, relaxometry, thermometry,
• MeSH
• diamant * MeSH
• dusík MeSH
• magnetismus MeSH
• nanočástice * MeSH
• teplota MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• diamant * MeSH
• dusík MeSH

We investigate the rich magnetic switching properties of nanoscale antidot lattices in the 200 nm regime. In-plane magnetized Fe, Co, and Permalloy (Py) as well as out-of-plane magnetized GdFe antidot films are prepared by a modified nanosphere lithography allowing for non-close packed voids in a magnetic film. We present a magnetometry protocol based on magneto-optical Kerr microscopy elucidating the switching modes using first-order reversal curves. The combination of various magnetometry and magnetic microscopy techniques as well as micromagnetic simulations delivers a thorough understanding of the switching modes. While part of the investigations has been published before, we summarize these results and add significant new insights in the magnetism of exchange-coupled antidot lattices.

• Klíčová slova
• Kerr microscopy, X-ray microscopy, antidot lattice, first-order reversal curves, magnetic nanostructures, magnetic switching, micromagnetic simulations, plasma etching, spin ice,
• Publikační typ
• časopisecké články MeSH