Serotonin transporter availability increases in patients recovering from a depressive episode

Molecular imaging studies have shown low cerebral concentration of serotonin transporter in patients suffering from depression, compared to healthy control subjects. Whether or not this difference also is present before disease onset and after remission (i.e. a trait), or only at the time of the depressive episode (i.e. a state) remains to be explored. We examined 17 patients with major depressive disorder with positron emission tomography using [11C]MADAM, a radioligand that binds to the serotonin transporter, before and after treatment with internet-based cognitive behavioral therapy. In all, 17 matched healthy control subjects were examined once. Cerebellum was used as reference to calculate the binding potential. Differences before and after treatment, as well as between patients and controls, were assessed in a composite cerebral region and in the median raphe nuclei. All image analyses and confirmatory statistical tests were preregistered. Depression severity decreased following treatment (p < 0.001). [11C]MADAM binding in patients increased in the composite region after treatment (p = 0.01), while no change was observed in the median raphe (p = 0.51). No significant difference between patients at baseline and healthy controls were observed in the composite region (p = 0.97) or the median raphe (p = 0.95). Our main finding was that patients suffering from a depressive episode show an overall increase in cerebral serotonin transporter availability as symptoms are alleviated. Our results suggest that previously reported cross-sectional molecular imaging findings of the serotonin transporter in depression most likely reflect the depressive state, rather than a permanent trait. The finding adds new information on the pathophysiology of major depressive disorder.

Boron Concentration Induced Co-Ta-B Composite Formation Observed in the Transition from Metallic to Covalent Glasses

Due to their unique property combination of high strength and toughness, metallic glasses are promising materials for structural applications. As the behaviour of metallic glasses depends on the electronic structure which in turn is defined by chemical composition, we systematically investigate the influence of B concentration on glass transition, topology, magnetism, and bonding for B concentrations x = 2 to 92 at.% in the (Co6.8±3.9Ta)100−xBx system. From an electronic structure and coordination point of view, the B concentration range is divided into three regions: Below 39 ± 5 at.% B, the material is a metallic glass due to the dominance of metallic bonds. Above 69 ± 6 at.%, the presence of an icosahedra-like B network is observed. As the B concentration is increased above 39 ± 5 at.%, the B network evolves while the metallic coordination of the material decreases until the B concentration of 67 ± 5 at.% is reached. Hence, a composite is formed. It is evident that, based on the B concentration, the ratio of metallic bonding to icosahedral bonding in the composite can be controlled. It is proposed that, by tuning the coordination in the composite region, glassy materials with defined plasticity and processability can be designed.

A Resonated and Synchrophased Three Beams Neutron Cancer Therapy Installation

The technique of composite region coupling by a neutron source at a common boundary of different regions that has been introduced in 2019 has allowed for an additive separation of variables neutron-density 3D wave analytical solution to the posing four-regional boundary value problem (BVP) of neutron cancer therapy (NCT). The three employable mutually orthogonal neutron beams, which may have different pulse shapes, have distinct modulation frequencies ω,ϖ, and ŵ and distinct relative time delays ε and ε̂. By employing this solution, we demonstrate in this paper how the therapeutic utility index and the ballistic index for this kind of dynamical NCT form a nonlinear optimization problem. Both of these indices are demonstrated to be remarkably periodically discontinuous in ε or ε̂, even in the neighborhood of the respective ε∗ or ε̂∗. As an extension of a result obtained also in 2019, for a certain lower-dimensional setup, a Pareto optimal control vector ω∗=(ω∗,ϖ∗,ε∗,ŵ∗,ε̂∗) is identified for this 3D problem. The existence of this vector paves the way toward what we call a “resonated and synchrophased three beams neutron cancer therapy (RASP-3BNCT) installation.”

Microstructure and Mechanical Properties of Al/AlN Surface Composite Fabricated via Multi-Pass Friction Stir Processing

The AlN particles reinforced composite was fabricated on the surface of aluminum 6061-T6 alloy rolled plate by five passes friction stir processing (FSP). Microstructure of FSPed sample was characterized by optical microscope and scanning electron microscope. AlN particles in composite were verified by EDS and XRD. Microhardness and resistance to wear were also investigated. Results show that grains in composite were refined by dynamic recrystallization and uniformly dispersed AlN particles. Composite region bonded with the Al substrate well. No reaction occurred at the interface between AlN and Al matrix. By comparison with base metal, the FSP-produced composite exhibited improved microhardness and substantial wear weight loss reduction.

Pinpoint Nano-Crystallization and Magnetization in Fe-Nd-B Metallic Glass by Electron Irradiation

Pinpoint nano-crystallization in Fe-based metallic glass was achieved by 2.0MV electron irradiation. Circular nano-crystalline structure regions with about 1μm in diameter were formed in the metallic glass and they were well dispersed in the amorphous matrix. In Fe77.5Nd4B18.5 alloy, micrometer order hard magnetic nano-composite region was formed in non-magnetic metallic glass matrix by electron irradiation. Electron irradiation induced crystallization is very effective for obtaining superior functional metallic materials with fine magnetic domains.