Vitacrystallography: Structural Biomarkers of Breast Cancer Obtained by X-ray Scattering.

With breast cancer being one of the most widespread causes of death for women, there is an unmet need for its early detection. For this purpose, we propose a non-invasive approach based on X-ray scattering. We measured samples from 107 unique patients provided by the Breast Cancer Now Tissue Biobank, with the total dataset containing 2958 entries.

Persistence of Correlations in Neurotransmitter Transport through the Synaptic Cleft.

The "quantum brain" proposal can revolutionize our understanding of cognition if proven valid. The core of the most common "quantum brain" mechanism is the appearance of correlated neuron triggering induced by quantum correlations between ions. In this work, we examine the preservation of the correlations created in the pre-synaptic neurons through the transfer of neurotransmitters across the synaptic cleft, a critical ingredient for the validity of the "quantum brain" hypothesis.

Canine Cancer Diagnostics by X-ray Diffraction of Claws.

We report the results of X-ray diffraction (XRD) measurements of the dogs' claws and show the feasibility of using this approach for early, non-invasive cancer detection. The obtained two-dimensional XRD patterns can be described by Fourier coefficients, which were calculated for the radial and circular (angular) directions. We analyzed these coefficients using the supervised learning algorithm, which implies optimization of the random forest classifier by using samples from the training group and following the calculation of mean cancer probability per patient for the blind dataset.

Mitochondria at the Nanoscale: Physics Meets Biology-What Does It Mean for Medicine?

Mitochondria are commonly perceived as "cellular power plants". Intriguingly, power conversion is not their only function. In the first part of this paper, we review the role of mitochondria in the evolution of eukaryotic organisms and in the regulation of the human body, specifically focusing on cancer and autism in relation to mitochondrial dysfunction.

Acoustically Induced Giant Synthetic Hall Voltages in Graphene.

Any departure from graphene's flatness leads to the emergence of artificial gauge fields that act on the motion of the Dirac fermions through an associated pseudomagnetic field. Here, we demonstrate the tunability of strong gauge fields in nonlocal experiments using a large planar graphene sheet that conforms to the deformation of a piezoelectric layer by a surface acoustic wave. The acoustic wave induces a longitudinal and a giant synthetic Hall voltage in the absence of external magnetic fields.

Cytochrome c oxidase oxygen reduction reaction induced by cytochrome c on nickel-coordination surfaces based on graphene oxide in suspension.

Background: The electrochemical and spectroscopic investigation of bacterial electron-transfer proteins stabilized on solid state electrodes has provided an effective approach for functional respiratory enzyme studies.

Methods: We assess the biocompatibility of carboxylated graphene oxide (CGO) functionalized with Nickel nitrilotriacetic groups (CGO-NiNTA) ccordinating His-tagged cytochrome c oxidase (CcO) from Rhodobacter sphaeroides.

Results: Kinetic studies employing UV-visible absorption spectroscopy confirmed that the immobilized CcO oxidized horse-heart cytochrome c (Cyt c) albeit at a slower rate than isolated CcO.

Perylene bisbenzimidazole nonlinear dielectric material for energy storage.

A novel perylene bisbenzimidazole comprising both donor and acceptor functional groups was designed, synthesized, and characterized. This structure exhibits potentially useful physical properties, including a nonlinear dielectric response to an increasing electric field. This material can be used in energy storage devices as the dielectric part of a capacitor.

Stochastic resonance in a proton pumping Complex I of mitochondria membranes.

We make use of the physical mechanism of proton pumping in the so-called Complex I within mitochondria membranes. Our model is based on sequential charge transfer assisted by conformational changes which facilitate the indirect electron-proton coupling. The equations of motion for the proton operators are derived and solved numerically in combination with the phenomenological Langevin equation describing the periodic conformational changes.

Energy transfer efficiency in the chromophore network strongly coupled to a vibrational mode.

Using methods from condensed matter and statistical physics, we examine the transport of excitons through the photosynthetic complex from a receiving antenna to a reaction center. Writing the equations of motion for the exciton creation-annihilation operators, we are able to describe the exciton dynamics, even in the regime when the reorganization energy is of the order of the intrasystem couplings. We determine the exciton transfer efficiency in the presence of a quenching field and protein environment.

Optimal rates for electron transfer in Marcus theory.

We examine electron transfer between two quantum states in the presence of a dissipative environment represented as a set of independent harmonic oscillators. For this simple model, the Marcus transfer rates can be derived from the equations of motion for electronic operators and we show that these rates are associated to an explicit expression for the environment correlation time. We demonstrate that as a manifestation of the Goldilocks principle, the optimal transfer is governed by a single parameter which is equal to just the inverse square root of 2.

Zener tunneling in semiconductor superlattices.

Characteristics of miniband tunneling and Wannier-Stark levels in semiconductor superlattices are studied as regards their dependence on the symmetry of the unit cells and the type of miniband structure. We modify the k ⋅ p method into a k ⋅ v form and on this basis generalize the Zener formula for the inter-band tunneling in homogeneous semiconductors to the case of inter-miniband tunneling in superlattices, account being taken of the inhomogeneity of the electron effective mass. The corresponding sum rule for the effective masses in such structures is obtained.

Electrostatic models of electron-driven proton transfer across a lipid membrane.

We present two models for electron-driven uphill proton transport across lipid membranes, with the electron energy converted to the proton gradient via the electrostatic interaction. In the first model, associated with the cytochrome c oxidase complex in the inner mitochondria membranes, the electrostatic coupling to the site occupied by an electron lowers the energy level of the proton-binding site, making proton transfer possible. In the second model, roughly describing the redox loop in a nitrate respiration of E.

Kinetics of proton pumping in cytochrome c oxidase.

We propose a simple model of cytochrome c oxidase, including four redox centers and four protonable sites, to study the time evolution of electrostatically coupled electron and proton transfers initiated by the injection of a single electron into the enzyme. We derive a system of master equations for electron and proton state probabilities and show that an efficient pumping of protons across the membrane can be obtained for a reasonable set of parameters. All four experimentally observed kinetic phases appear naturally from our model.

Proton transport and torque generation in rotary biomotors.

We analyze the dynamics of rotary biomotors within a simple nanoelectromechanical model, consisting of a stator part and a ring-shaped rotor having 12 proton-binding sites. This model is closely related to the membrane-embedded F0 motor of adenosine triphosphate (ATP) synthase, which converts the energy of the transmembrane electrochemical gradient of protons into mechanical motion of the rotor. It is shown that the Coulomb coupling between the negative charge of the empty rotor site and the positive stator charge, located near the periplasmic proton-conducting channel (proton source), plays a dominant role in the torque-generating process.

Förster mechanism of electron-driven proton pumps.

We examine a simple model of proton pumping through the inner membrane of mitochondria in the living cell. We demonstrate that the pumping process can be described using approaches of condensed matter physics. In the framework of this model, we show that the resonant Förster-type energy exchange due to electron-proton Coulomb interaction can provide a unidirectional flow of protons against an electrochemical proton gradient, thereby accomplishing proton pumping.

Probing the microscopic structure of bound states in quantum point contacts.

Using an approach that allows us to probe the electronic structure of strongly pinched-off quantum point contacts (QPCs), we provide evidence for the formation of self-consistently realized bound states (BSs) in these structures. Our approach exploits the resonant interaction between closely coupled QPCs, and demonstrates that the BSs may give rise to a robust confinement of single spins, which show clear Zeeman splitting in a magnetic field.

Detection of local-moment formation using the resonant interaction between coupled quantum wires.

We study the influence of many-body interactions on the transport characteristics of a pair of quantum wires that are coupled to each other by means of a quantum dot. Under conditions where a local magnetic moment is formed in one of the wires, tunnel coupling to the other gives rise to an associated peak in its density of states, which can be detected directly in a conductance measurement. Our theory is therefore able to account for the key observations in the recent study of T.