Pilot study of an occupational healthcare program to assess the SARS-CoV-2 infection and immune status of employees in a large pharmaceutical company.

OBJECTIVE: To safeguard key workers involved in development and production of medicines and ensure business continuity, we developed an occupational healthcare program, performed by our company's occupational healthcare services, to assess the infection and immune status for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This pilot program, conducted at our company facilities, evaluated the suitability of diagnostic tools in our setting for program upscaling. METHODS: We used different marketed in vitro diagnostics (including tests for antibodies against spike protein subunits S1 and S2 and nucleocapsid [N] protein) combined with medical history, symptoms and likelihood of infection. We evaluated the testing strategy over four visits in 141 employees (known positive COVID-19 history, n = 20; unknown status, n = 121) between April and June 2020 at four company locations in Germany. Digital self-monitoring over the pilot program duration was also included. RESULTS: No incident infections were detected. Based on immune status, medical history and likelihood of infection, 10 participants (8.3%) with previously unknown history of COVID-19 were identified to have been infected before entering the program. These participants, who recalled no or mild symptoms in the preceding months, were primarily identified using an assay that detected both S1 and S2 immunoglobulin (Ig) G. The frequency of positive lateral flow assay (LFA) results (IgM or IgG directed against the N-protein) in this cohort was lower compared with participants with a known history of COVID-19 (0‒10.8% vs. 33.8‒75.7%, respectively). CONCLUSIONS: Data from this pilot program suggest that LFA for antibodies may not always reliably detect current, recent or past infections; consequently, these have not been included in our upscaled occupational healthcare program. Regular testing strategies for viral RNA and antibodies directed against different SARS-CoV-2 proteins, combined with hygiene rules and a comprehensive baseline assessment, are recommended to ensure avoidance of infections at workplace as reliably as possible.

Effectiveness of imepitoin for the control of anxiety and fear associated with noise phobia in dogs.

BACKGROUND: Noise phobia is a common behavior problem in dogs for which there are limited treatment options. OBJECTIVE: To evaluate the efficacy and safety of imepitoin in comparison to placebo for the control of anxiety and fear associated with noise phobia in dogs. ANIMALS: Two hundred thirty-eight client-owned dogs with noise phobia were recruited in veterinary clinics. METHODS: This placebo-controlled, randomized, double-blinded, clinical trial used a predictable noise event as eliciting context, the traditional New Year's Eve fireworks in Germany and the Netherlands. Owners began treatment 2 days before the anticipated noise event with administration of either imepitoin 30 mg/kg body weight Q12h or placebo for 3 consecutive days. On New Year's Eve, owners noted their observations of their dog's fear and anxiety behavior at 1600, 2200, 0020, and 0100 hours and scored the overall treatment effect on the following day. RESULTS: In the 16-item owner report of fear and anxiety signs, fear and anxiety behaviors were significantly reduced under imepitoin treatment compared to placebo (delta -6.1 scoring points; P < .0001). A significantly higher proportion of owners reported a good or excellent overall treatment effect in the imepitoin group compared to placebo (odds ratio 4.689; 95% CI, 2.79-7.89; P < .0001). CONCLUSION: Imepitoin effectively controls fear and anxiety associated with noise phobia in dogs.

Ferrofluids as thermal ratchets.

Colloidal suspensions of ferromagnetic nanoparticles, so-called ferrofluids, are shown to be suitable systems to demonstrate and investigate thermal ratchet behavior: By rectifying thermal fluctuations, angular momentum is transferred to a resting ferrofluid from an oscillating magnetic field without net rotating component. Via viscous coupling the noise driven rotation of the microscopic ferromagnetic grains is transmitted to the carrier liquid to yield a macroscopic torque. For a simple setup we analyze the rotation of the ferrofluid theoretically and show that the results are compatible with the outcome of a simple demonstration experiment.

Thermal convection in binary fluid mixtures with a weak concentration diffusivity, but strong solutal buoyancy forces.

Thermal convection in binary liquid mixtures is investigated in the limit where the solutal diffusivity is weak, but the separation ratio is large. Representative examples are colloidal suspensions such as ferrofluids. With a grain size being large on molecular length scales, the particle mobility is extremely small, allowing to disregard the concentration dynamics in most cases. However, this simplification does not hold for thermal convection: Due to the pronounced Soret effect of these materials in combination with a considerable solutal expansion, the resulting solutal buoyancy forces are dominant. Indeed, convective motion is found to set in at Rayleigh numbers well below the critical threshold for single-component liquids. A nonlinear analysis demonstrates that the amplitude quickly saturates in a state of stationary convective motion.

Sound damping in ferrofluids: magnetically enhanced compressional viscosity.

The damping of sound waves in magnetized ferrofluids is investigated and shown to be considerably higher than in the nonmagnetized case. This fact may be interpreted as a field-enhanced, effective compressional viscosity-in analogy to the ubiquitous field-enhanced shear viscosity that is known to be the reason for many unusual behaviors of ferrofluids under shear.

Molecular dynamics study on the equilibrium magnetization properties and structure of ferrofluids.

We investigate in detail the initial susceptibility, magnetization curves, and microstructure of ferrofluids in various concentration and particle dipole moment ranges by means of molecular dynamics simulations. We use the Ewald summation for the long-range dipolar interactions, take explicitly into account the translational and rotational degrees of freedom, coupled to a Langevin thermostat. When the dipolar interaction energy is comparable with the thermal energy, the simulation results on the magnetization properties agree with the theoretical predictions very well. For stronger dipolar couplings, however, we find systematic deviations from the theoretical curves. We analyze in detail the observed microstructure of the fluids under different conditions. The formation of clusters is found to enhance the magnetization at weak fields and thus leads to a larger initial susceptibility. The influence of the particle aggregation is isolated by studying ferro-solids, which consist of magnetic dipoles frozen in at random locations but which are free to rotate. Due to the artificial suppression of clusters in ferrosolids the observed susceptibility is considerably lowered when compared to ferrofluids.

Shear-excited sound in magnetic fluid.

Perceptible sound is shown to be excited in ferrofluids by the shear motion of a rigid plate, if the fluid is exposed to a magnetic field oblique both to the plate and to the direction of propagation. This is in contrast to other fluids, including anisotropic ones such as nematic liquids.

Stationary off-equilibrium magnetization in ferrofluids under rotational and elongational Flow.

The magnetization of a ferrofluid, which is exposed to a flow, was recently proposed to depend on the symmetric velocity gradients (elongational flow). This is demonstrated by an experimental setup, which allows one to evaluate the transport coefficient associated with the elongational flow contribution.