Wide range linear magnetometer based on a sub-microsized K vapor cell.

39K atoms have the smallest ground state (2S1/2) hyperfine splitting of all the most naturally abundant alkali isotopes and, consequently, the smallest characteristic magnetic field value B0=A2S1/2/µB≈170G, where A2S1/2 is the ground state's magnetic dipole interaction constant. In the hyperfine Paschen-Back regime (B≫B0, where B is the magnitude of the external magnetic field applied on the atoms), only eight Zeeman transitions are visible in the absorption spectrum of the D1 line of 39K, while the probabilities of the remaining 16 Zeeman transitions tend to zero. In the case of 39K, this behavior is reached already at relatively low magnetic field B>B0. For each circular polarization (σ-,σ+), four spectrally resolved atomic transitions having sub-Doppler widths are recorded using a sub-microsized vapor cell of thickness L=120-390nm. We present a method that allows to measure the magnetic field in the range of 0.1-10kG with micrometer spatial resolution, which is relevant in particular for the determination of magnetic fields with large gradients (up to 3 G/µm). The theoretical model describes well the experimental results.

[Acute kidney injury in the pathogenesis of coronavirus infection].

COVID-19 is an acute respiratory viral disease that primarily affects the lungs, but can also affect other organs, including the kidneys. Damage to the kidneys can be caused by direct effects arising from the invasion of the virus into kidney cells, or it occurs secondarily due to immunological, hemocoagulation and ischemic disorders. Given the importance of preserving kidney function during illness and after recovery, this review aims to investigate the impact of novel coronavirus infection on the kidney and its role in the development of acute kidney injury.

Approach to quantitative spectroscopy of atomic vapor in optical nanocells.

We present a method for recovery of narrow homogeneous spectral features out of a broad inhomogeneous overlapped profile based on second-derivative processing of the absorption spectra of alkali metal atomic vapor nanocells. The method is shown to preserve the frequency positions and amplitudes of spectral transitions, thus being applicable for quantitative spectroscopy. The proposed technique was successfully applied and tested for measurements of hyperfine splitting and atomic transition probabilities, development of an atomic frequency reference, determination of isotopic abundance, study of atom-surface interaction, and determination of magnetic-field-induced modification of atomic transition frequency and probability. The obtained experimental results are fully consistent with theoretical modeling.

Nonlinear forward scattering in cesium vapor: experiment with simultaneous scanning of laser frequency and B-field.

We present the results of an experimental study of nonlinear magneto-optical rotation in a buffer-gas-free uncoated Cs cell on hyperfine transitions F(g) = 3 --> F(e) = 2, 3, 4 of the D(2) line at high laser irradiance (up to 40 mW/cm(2)). The measurements were done in a forward scattering configuration, with simultaneous linear scanning of laser frequency and magnetic field at different temporal rates. The latter revealed, in a single measurement, the dependences of maximum nonlinear Faraday signal and the corresponding B-field on the laser frequency within the Doppler profile.

Frequency-stabilized high-power ruby laser Q switched by Rb(2) vapor.

Passive Q switching of a ruby laser by the use of molecular rubidium (Rb(2)) vapor has been realized. For the first time, to our knowledge, an integrally sapphire cell containing Rb(2) vapor was used as the saturable absorber, which ensures an operation period of several years. Single-frequency-stabilized giant pulses with 700-mJ energy, 22-ns duration, and 200-MHz spectral width were obtained.

Cadmium effects on Ichthyophthirius: evidence for metal-sequestration in fish tissues following administration of recombinant vaccines.

We are developing Tetrahymena thermophila as a delivery system for recombinant vaccines against parasitic protozoa, including the common fish parasite, Ichthyophthirius multifiliis. T. thermophila cell lines expressing I. multifiliis genes under the control of a cadmium-inducible metallothionein gene promoter conferred strong protection against a lethal parasite challenge when administered parenterally to naive fish. Nevertheless, given that heavy metals can be toxic to parasites, a question arose as to whether protection resulted from Cd residues carried over with the vaccine, rather than acquired immunity per se. To address this issue, we examined the sensitivity of I. multifiliis to Cd in vitro and determined Cd concentrations in different host tissues following i.p. injection of juvenile channel catfish with the recombinant vaccine. We found that CdCl2 at concentrations > or = 50 ppb were lethal to I. multifiliis theronts in vitro. Furthermore, Cd concentrations were clearly elevated in fish tissues and reached levels equivalent to 74 ng/g wet weight (74 ppb) in the skin within 14 days of injection with recombinant T. thermophila. Nevertheless, fish injected with non-transformed Tetrahymena grown in the presence or absence of CdCl2 showed no significant difference in either relative survival or parasite load following direct challenge with I. multifiliis.

New manifestation of atomic parity violation in cesium: a chiral optical gain induced by linearly polarized 6S-7S excitation.

We have detected, by using stimulated emission, an atomic parity violation (APV) in the form of a chiral optical gain of a cesium vapor on the 7S-6P(3/2) transition, consecutive to linearly polarized 6S-7S excitation. We demonstrate the validity of this detection method of APV, by presenting a 9% accurate measurement of expected sign and magnitude. We stress several advantages of this new approach which fully exploits the cylindrical symmetry of the setup. Future measurements at the percent level will provide an important cross-check of an existing more precise result obtained by a different method.