Feather-Processing Wastewater: Composition, Infl uence on the Natural Water Objects and Decontamination Technologies

Poultry farming and production is one of very important branches of the food and food processing industry, which produces important foodstuffs, semi-fi nished products and by-products for further processing. Intense processing of the poultry products results in a massive formation of the heavily polluted wastewaters containing many hazardous pollutants. This problem is very acute for many countries where this branch is quick-growing and being under extended investigation of various decontamination methods of the poultry processing wastewaters. Poultry feather is not involved in any food processing industry but can be used as an adsorbent or fi ller for some clothes and bed clothes. Relevant industrial feather-processing stages also produce some contaminated wastewaters and a problem of their decontamination is still beyond systematic analysis and investigation. This paper deals with analysis of the poultry feather-processing wastewaters composition and experimental investigation of various methods and technologies of their decontamination. Iron chloride combined with polyacrylamide ensured the best wastewater cleaning/fl occulation activity and a combined wastewater treatment scheme with primary cleaning/fl occulation, secondary complex biotreatment and tertiary sand-fi ltration has been proposed in order to reach a required decontamination depth. This technology proves the wastewater quality, which complies with the offi cially set limits

New environment- friendly etching technologies for some steels and copper alloys

New compositions containing some organic inhibitors were tested in the carbon steels and copper alloys etching processes. The analysis of the etching efficiency and harmful products emission proves that significant reduction in the specific discharge of the waste waters and emission of nitrogen oxides can be achieved at the appropriate etching qualit

Development of a protocol for maintaining viability while shipping organoid-derived retinal tissue.

Retinal organoid technology enables generation of an inexhaustible supply of three-dimensional retinal tissue from human pluripotent stem cells (hPSCs) for regenerative medicine applications. The high similarity of organoid-derived retinal tissue and transplantable human fetal retina provides an opportunity for evaluating and modeling retinal tissue replacement strategies in relevant animal models in the effort to develop a functional retinal patch to restore vision in patients with profound blindness caused by retinal degeneration. Because of the complexity of this very promising approach requiring specialized stem cell and grafting techniques, the tasks of retinal tissue derivation and transplantation are frequently split between geographically distant teams. Delivery of delicate and perishable neural tissue such as retina to the surgical sites requires a reliable shipping protocol and also controlled temperature conditions with damage-reporting mechanisms in place to prevent transplantation of tissue damaged in transit into expensive animal models. We have developed a robust overnight tissue shipping protocol providing reliable temperature control, live monitoring of the shipment conditions and physical location of the package, and damage reporting at the time of delivery. This allows for shipping of viable (transplantation-competent) hPSC-derived retinal tissue over large distances, thus enabling stem cell and surgical teams from different parts of the country to work together and maximize successful engraftment of organoid-derived retinal tissue. Although this protocol was developed for preclinical in vivo studies in animal models, it is potentially translatable for clinical transplantation in the future and will contribute to developing clinical protocols for restoring vision in patients with retinal degeneration

Boson-like quantum dynamics of association in ultracold Fermi gases

We study the collective association dynamics of a cold Fermi gas of $2N$ atoms in $M$ atomic modes into a single molecular bosonic mode. The many-body fermionic problem for $2^M$ amplitudes is effectively reduced to a dynamical system of $\min\{N,M\}+1$ amplitudes, making the solution no more complex than the solution of a two-mode Bose-Einstein condensate and allowing realistic calculations with up to $10^4$ particles. The many-body dynamics is shown to be formally similar to the dynamics of the bosonic system under the mapping of boson particles to fermion holes, producing collective enhancement effects due to many-particle constructive interference. Dissociation rates are shown to enhance as the number of particles whereas association rates are enhanced as the number of holes, leading to boson-like collective behavior.Comment: 5 pages, 2 figures, critical typo in Eq. (13) correcte

Spin-orbit coupled particle in a spin bath

We consider a spin-orbit coupled particle confined in a quantum dot in a bath of impurity spins. We investigate the consequences of spin-orbit coupling on the interactions that the particle mediates in the spin bath. We show that in the presence of spin-orbit coupling, the impurity-impurity interactions are no longer spin-conserving. We quantify the degree of this symmetry breaking and show how it relates to the spin-orbit coupling strength. We identify several ways how the impurity ensemble can in this way relax its spin by coupling to phonons. A typical resulting relaxation rate for a self-assembled Mn-doped ZnTe quantum dot populated by a hole is 1 $\mu$s. We also show that decoherence arising from nuclear spins in lateral quantum dots is still removable by a spin echo protocol, even if the confined electron is spin-orbit coupled.Comment: 18 pages, 1 figur

Electron tunneling through sensitizer wires bound to proteins

We report a quantitative theoretical analysis of long-range electron transfer through sensitizer wires bound in the active-site channel of cytochrome P450cam. Each sensitizer wire consists of a substrate group with high binding affinity for the enzyme active site connected to a ruthenium-diimine through a bridging aliphatic or aromatic chain. Experiments have revealed a dramatic dependence of electron transfer rates on the chemical composition of both the bridging group and the substrate. Using combined molecular dynamics simulations and electronic coupling calculations, we show that electron tunneling through perfluorinated aromatic bridges is promoted by enhanced superexchange coupling through virtual reduced states. In contrast, electron flow through aliphatic bridges occurs by hole-mediated superexchange. We have found that a small number of wire conformations with strong donor–acceptor couplings can account for the observed electron tunneling rates for sensitizer wires terminated with either ethylbenzene or adamantane. In these instances, the rate is dependent not only on electronic coupling of the donor and acceptor but also on the nuclear motion of the sensitizer wire, necessitating the calculation of average rates over the course of a molecular dynamics simulation. These calculations along with related recent findings have made it possible to analyze the results of many other sensitizer-wire experiments that in turn point to new directions in our attempts to observe reactive intermediates in the catalytic cycles of P450 and other heme enzymes

Comparison of Electron-Atom Collision Parameters for S to P Transitions under Reversal of Energy Transfer

Inelastic and superelastic electron scattering from the optically prepared 32P3/2 state of sodium has enabled atomic collision parameters to be deduced for the 4S-3P deexcitation and the 3S-3P excitation processes. These data are compared with convergent close coupling and second order distorted wave Born calculations. For excitation, both theories agree with experiment, whereas for deexcitation the close coupling theory is in better agreement. A long-standing proposal relating to the sign of the transferred angular momentum is not supported