Non-Markovian master equation for quantum transport of fermionic carriers.

We propose a simple, yet feasible, model for quantum transport of fermionic carriers across tight-binding chain connecting two reservoirs maintained at arbitrary temperatures and chemical potentials. The model allows for elementary derivation of the master equation for the reduced single particle density matrix (SPDM) in a closed form in both Markov and Born approximations. In the Markov approximation the master equation is solved analytically, whereas in the Born approximation the problem is reduced to an algebraic equation for the SPDM in the Redfield form. The non-Markovian equation is shown to lead to resonant transport similar to Landauer's conductance. It is shown that in the deep non-Markovian regime the transport current can be matched with that obtained by the non-equilibrium Green's function method.

Synchrotron single-crystal XRD, IR-, Raman spectroscopy and high pressure study of synthetic krieselite.

Spontaneous crystals of krieselite (Ge analogue of topaz) with the chemical formula Al2[(Ge0.75Si0.25)O4](F1.63OH0.37) were synthesized using a thermo-gradient hydrothermal method at a temperature of 600/650 °C and pressure of 100 MPa. The unit cell parameters are: a = 8.9732(8) Å, b = 8.4823(7) Å, c = 4.7379(5) Å, V = 360.62(6) Å3, space group Pnma. The F-/OH- content of the samples was refined by FTIR spectroscopy method. Raman spectroscopy showed the main differences between the spectra of krieselite and topaz at the ambient conditions. The assignment of observed and calculated Ag bands (cm-1) for non-polarized Raman spectra was carried out. Using in situ Raman spectroscopy at high pressures, the dependence of the shift in the position of the main bands of the krieselite Raman spectrum on the pressure was established, and the corresponding paths of pressure induced distortion of crystal structure was assumed. According to the data of Raman spectroscopy, it was revealed that krieselite does not undergo the phase transitions up to 30 GPa. The probable way of crystal structure distortion within the space group Pnma was proposed based on simulation of high-pressure Raman spectra.

Manifestation of Majorana modes overlap in the Aharonov-Bohm effect.

One of the key features of the Majorana bound states emerging in topological superconducting (SC) wires is increasing oscillations of their energy under the growth of magnetic field or chemical potential due to concomitant enhancement of hybridization of the Majorana mode wave functions initially localized at the opposite edges of the structure. In this study we found that the other consequence of it is a shift of Aharonov-Bohm (AB) oscillations of linear-response conductance in an interference device where two ends of the SC wire connected with a normal contact via non-SC wires (arms). In addition, it is accompanied by an oscillation period doubling. The numerical calculations for the spinful system are supported by the analytical results for different spinless models allowing to track the conductance evolution as the hybridization of the Majorana modes increases. It is shown that since the coupling between the different arms and normal contact is implemented only via the different-type Majoranas the AB oscillations acquire a fundamentalπ/2 shift in comparison with the effect for an analogous system of zero-energy quantum dots.

[Resection of retroperitoneal leiomyosarcoma followed by replacement of cavarenal segment of inferior vena cava]. / Udalenie zabryushinnoi leiomiosarkomy s rezektsiei i protezirovaniem kavarenal'nogo segmenta nizhnei poloi veny Klinicheskoe nablyudenie.

The authors reported a rare clinical case of successful surgical treatment of young female with retroperitoneal leiomyosarcoma followed by lesion of the cavarenal segment of inferior vena cava, left renal vein. Clinical and morphological features of disease, postoperative outcomes and prognostic factors in patients with retroperitoneal leiomyosarcoma are discussed.

Fano effect in Aharonov-Bohm ring with topologically superconducting bridge.

Taking into account an inner structure of the arms of the Aharonov-Bohm ring (AB ring) we have analyzed the transport features related to the topological phase transition which is induced in a superconducting wire (SC wire) with strong spin-orbit interaction (SOI). The SC wire acts as a bridge connecting the arms. The in-plane magnetic-field dependence of linear-response conductance obtained using the nonequilibrium Green's functions in the tight-binding approximation revealed the Breit-Wigner and Fano resonances (FRs) if the wire is in the nontrivial phase. The effect is explained by the presence of two interacting transport channels in the system. As a result, the FRs are attributed to bound states in continuum (BSCs). The BSC lifetime is determined by both hopping parameters between subsystems and the SC-wire properties. It is established that the FR width and position are extremely sensitive to the type of the lowest-energy excitation in the SC wire, the Majorana or Andreev bound state (MBS or ABS, respectively). Moreover, it is shown that in the specific case of the AB ring, the T-shape geometry, the FR disappears for the transport via the MBS and the conductance is equal to one quantum. It doubles in the local transport regime. On the contrary, in the ABS case the local conductance vanishes. The influence of the mean-field Coulomb interactions and diagonal disorder in the SC wire on the FR is investigated.

Pharmacometric Modeling of Naloxegol Efficacy and Safety: Impact on Dose and Label.

Naloxegol is a peripherally acting µ-opioid receptor antagonist that was developed for the treatment of opioid-induced constipation. Modeling and simulation of naloxegol efficacy and tolerability informed selection of doses for phase III studies and provided comprehensive dosage recommendations for the naloxegol US package insert.

A multi-ingredient dietary supplement abolishes large-scale brain cell loss, improves sensory function, and prevents neuronal atrophy in aging mice.

Transgenic growth hormone mice (TGM) are a recognized model of accelerated aging with characteristics including chronic oxidative stress, reduced longevity, mitochondrial dysfunction, insulin resistance, muscle wasting, and elevated inflammatory processes. Growth hormone/IGF-1 activate the Target of Rapamycin known to promote aging. TGM particularly express severe cognitive decline. We previously reported that a multi-ingredient dietary supplement (MDS) designed to offset five mechanisms associated with aging extended longevity, ameliorated cognitive deterioration and significantly reduced age-related physical deterioration in both normal mice and TGM. Here we report that TGM lose more than 50% of cells in midbrain regions, including the cerebellum and olfactory bulb. This is comparable to severe Alzheimer's disease and likely explains their striking age-related cognitive impairment. We also demonstrate that the MDS completely abrogates this severe brain cell loss, reverses cognitive decline and augments sensory and motor function in aged mice. Additionally, histological examination of retinal structure revealed markers consistent with higher numbers of photoreceptor cells in aging and supplemented mice. We know of no other treatment with such efficacy, highlighting the potential for prevention or amelioration of human neuropathologies that are similarly associated with oxidative stress, inflammation and cellular dysfunction. Environ. Mol. Mutagen. 57:382-404, 2016. © 2016 Wiley Periodicals, Inc.

Population pharmacokinetics of inhaled tobramycin powder in cystic fibrosis patients.

Tobramycin powder for inhalation (TOBI Podhaler or TIP) is approved for the treatment of Pseudomonas aeruginosa airway infection in patients with cystic fibrosis (CF). A population pharmacokinetic model for tobramycin inhalation powder (TIP) in CF patients was developed to characterize the effect of covariates including body mass index (BMI) and lung function (forced expiratory volume in 1 s as percent of the predicted value (FEV1% predicted) at baseline) on the serum exposure parameters.A two-compartment model with first-order elimination and first-order absorption was developed. Across a range of baseline demographic values in the study population, the predicted mean values for the maximum (Cmax) and trough (Ctrough) plasma concentrations at steady state were at least 7.5 and 5-fold lower, respectively, than the recommended thresholds for tobramycin toxicity (12 µg/ml for Cmax and 2 µg/ml for Ctrough). This model adequately described the tobramycin serum concentration-time course in CF patients following inhalation of TIP. The results indicate that no BMI- or FEV1-based dose adjustment is needed for use of TIP in CF patients.

[Abdominal vascular structural and functional features in patients with connective tissue dysplasia].

Doppler ultrasound study records decreased volume blood flow in patients with connective tissue dysplasia. Their hemodynamic features are more marked during food testing. Dysplasia-dependent structural changes in the vascular system, such as vascular hypoplasia, wall-occluding lesions, different types of deformities, are one of the causes of lower volumetric blood flow in the abdominal vessels. The found abdominal vascular structural and functional features in patients with connective tissue dysplasia can serve as the basis for blood flow disproportion in different stages of digestion.

[On the mechanisms of stimulation and inhibition during germination of wheat seeds in extremely low frequency electromagnetic fields].

It has been shown that the effects of stimulation of germination of wheat seeds by electromagnetic field depend on the degree of membrane tension during imbibition of seeds in sucrose solutions. This provides further confirmation of the influence of electromagnetic fields on the release of proteins from the bound state on the membranes. The prolonged treatment with electromagnetic fields during the imbibition of seeds leads not only to the inhibition of germination of sprouts but also to a decrease in their germinability, which can be as strong as twofold for seeds with the initial low germinability. This is related to the desynchronization of germination processes, caused by the stimulation of the release of proteins and inhibition of another stage during the cell division, the assembly of complex structures. It is noted that the activation of the release of proteins and inhibition of their binding by the action of electromagnetic fields must elevate the cell excitability. The presumably, the excitability of cells determines the effects of magnetic storms and high solar activity on the physiological state of organisms.

Effect of unreamed, limited reamed, and standard reamed intramedullary nailing on cortical bone porosity and new bone formation.

OBJECTIVE: To compare the effects of unreamed nail insertion and reamed nail insertion with limited and standard canal reaming on cortical bone porosity and new bone formation. DESIGN: A canine segmental tibial fracture was created in fifteen adult dogs. The tibiae were stabilized with a statically locked 6.5-millimeter intramedullary nail without prior canal reaming (n = 5), after limited reaming to 7.0 millimeters (n = 5), or after standard canal reaming to 9.0 millimeters (n = 5). Porosity, new bone formation, and the mineral apposition rate of cortical bone were directly compared between the three nailing techniques. RESULTS: A significant increase in cortical bone porosity and new bone formation was seen in all three groups of experimental animals compared with the control tibiae. The overall lowest porosity levels were measured in the limited reamed group, with similar porosity levels measured in the unreamed and standard reamed groups. Porosity was lower in the limited reamed group in the entire cortex of the segmental and distal cross sections, as well as the endosteal, anterior, and posterior cortices along the length of the tibia. Overall, there was no difference in the amount of new bone formation or the mineral apposition rate between the three groups of animals at eleven weeks after surgery. DISCUSSION: The results of this study suggest that limited intramedullary reaming is a biologically sound alternative for the treatment of tibial diaphyseal fractures in which the circulation is already compromised.

[Characteristics of low frequency magnetic field effect on swelling of wheat seeds at various stages]. / Osobennosti vliianiia nizkochastotnogo magnitnogo polia na nabukhanie semian pshenitsy na razlichnykh stadiiakh.

Low-frequency magnetic field treatment (50 Hz, 30 mT, 15 min) of wheat seeds with a 50% germination efficiency during imbibition at the stage of root formation leads to a statistically significant increase in the number of seeds having sprouts, a still greater increase in the number of seeds having roots, and to an increase in the length of sprouts compared with the control and the seeds treated several hours later. In the last case, an increase in the germinating capacity with a considerably lesser effect on the number of seeds with roots was also observed. Prolonged treatment with the field during the second day of imbibition decreased reliably the length of sprouts with a weaker influence on the number of seeds with sprouts and roots. These data suggest the principal possibility of the effect of electromagnetic fields on the realization of the genetic program during the germination of wheat seeds.

Blood flow changes to the proximal femur during total hip arthroplasty.

OBJECTIVE: To determine the changes in perfusion to the proximal femur that occur during cemented and uncemented total hip arthroplasty (THA). DESIGN: Case series. SETTING: A single tertiary-care centre. PATIENTS: Twenty-two consecutive patients. Those who had undergone previous hip surgery or received systemic corticosteroid therapy were excluded. INTERVENTION: Cemented (11 procedures) or uncemented (12 procedures) THA. MAIN OUTCOME MEASURE: Changes in blood flow at the level of the proximal femur, measured with laser Doppler flowmetry at 4 different times during THA. RESULTS: In both the cemented and the uncemented procedure overall proximal femoral blood flow was reduced (p = 0.002, p = 0.008, respectively). A greater reduction in overall proximal femoral perfusion was seen in the cemented group compared with the uncemented group (p = 0.004). This greater reduction in perfusion was seen primarily in the proximal femoral diaphysis (p = 0.004). CONCLUSION: The extensive canal preparation involved with the cemented procedure or the introduction of bone cement under pressure into the femoral canal may contribute to the greater reduction in perfusion to the proximal femur.

[Effect of a low-frequencey magnetic field on esterase activity and change in pH in wheat germ during swelling of wehat seeds]. / Vliianie nizkochastotnogo magnitnogo polia na aktivnost' ésteraz i izmenenie pH u zarodysha v khode nabukhaniia semian pshenitsy.

The role of nonsteady phenomena determined by a low velocity of ion movements in a weak external field is considered in relation to their possible nonlinear effects on processes occurring in boundary layers near the membrane, particularly, on the release of membrane-bound proteins and pH value. It is shown that a short-term treatment of wheat seeds with low-frequency magnetic field at the stage of esterase activation during seed swelling enhances the activation of esterases; the effect observed at final stages of activation depends on the time after the treatment with electromagnetic field. Treatment of seeds with electromagnetic field at this stage changed qualitatively the time course of the release of reaction products into the medium: the reaction rate increased initially and then decreased below the control level. At earlier stages of swelling in treated seeds and at all stages in control seeds, the time course of the product release was linear. The retardation of the release of the reaction products at terminal stages of esterase activation is presumably related to the release of proteins and their complexes under the action of electromagnetic field and the resulting restoration of the barrier properties of membranes. Treatment with electromagnetic field also caused a noticeable acceleration of proton flow form the medium, which was judged from pH changes in the bulk medium and in the vicinity of germ surface. The difference between the treated and control samples after 23-24 h of imbibition became statistically significant and was as high as 0.4 pH units. By taking into account the nonsteady phenomena occurring upon action of low-frequency electromagnetic field, it is possible to explain unusual dependences of biological effects on the amplitude of the electromagnetic field, including the atypical enhancement of these effects by the action of weak low-frequency fields.

Pathophysiological effect of fat embolism in a canine model of pulmonary contusion.

BACKGROUND: The objective of this study was to determine the individual and combined effects of pulmonary contusion and fat embolism on the hemodynamics and pulmonary pathophysiology in a canine model of acute traumatic pulmonary injury. METHODS: After a thoracotomy, twenty-one skeletally mature dogs were randomly assigned to one of three groups. Unilateral pulmonary contusion alone was produced in Group 1 (seven dogs); pulmonary contusion and fat embolism, in Group 2 (seven dogs); and fat embolism alone, in Group 3 (seven dogs). Pulmonary contusion was produced by standardized compression of the left lung with a piezoelectric force transducer. Fat embolism was produced by femoral and tibial reaming followed by pressurization of the intramedullary canals. Cardiac output, systolic blood pressure, peak airway pressure, pulmonary arterial pressure, pulmonary capillary wedge pressure, partial pressure of arterial oxygen, and partial pressure of carbon dioxide were monitored for all groups. From these data, several outcome parameters were calculated: total thoracic compliance, alveolar-arterial oxygen gradient, and ratio of partial pressure of arterial oxygen to fractional inspired oxygen concentration. All of the dogs were killed after eight hours, and tissue samples were obtained from the brain, kidneys, and lungs for histological analysis. Lung samples were assigned scores for pulmonary edema (the presence of fluid in the alveoli) and inflammation (the presence of neutrophils or hyaline membranes, or both). The percentage of the total area occupied by fat was determined. RESULTS: Pulmonary contusion alone caused a significant increase in the alveolar-arterial oxygen gradient but only after seven hours (p = 0.034). Fat embolism alone caused a significant transient decrease in systolic blood pressure (p = 0.001) and a significant transient increase in pulmonary arterial pressure (p = 0.01) and pulmonary capillary wedge pressure (p = 0.015). Fat embolism alone also caused a significant sustained decrease in the ratio of partial pressure of arterial oxygen to fractional inspired oxygen concentration (p = 0.0001) and a significant increase in the alveolar-arterial oxygen gradient (p = 0.0001). The combination of pulmonary contusion and fat embolism caused a significant transient increase in pulmonary capillary wedge pressure (p = 0.0013) as well as a significant sustained decrease in partial pressure of arterial oxygen (p = 0.0001) and a significant decrease in systolic blood pressure (p = 0.001) that lasted for an hour. Pulmonary contusion followed by fat embolism caused a significant increase in peak airway pressure (p = 0.015), alveolar-arterial oxygen gradient (p = 0.0001), and pulmonary arterial pressure (p = 0.01), and these effects persisted for five hours. Total thoracic compliance was decreased 6.4 percent by pulmonary contusion alone, 4.6 percent by fat embolism alone, and 23.5 percent by pulmonary contusion followed by fat embolism. The ratio of partial pressure of arterial oxygen to fractional inspired oxygen concentration was decreased 23.7 percent by pulmonary contusion alone, 52.3 percent by fat embolism alone, and 65.8 percent by pulmonary contusion followed by fat embolism. The mean pulmonary edema score was significantly higher with the combined injury than with either injury alone (p = 0.0001). None of the samples from the lungs demonstrated inflammation. Fat embolism combined with pulmonary contusion resulted in a significantly greater mean percentage of the area occupied by fat in the noncontused right lung than in the contused left lung (p = 0.001); however, no significant difference between the right and left lungs could be detected with fat embolism alone. The mean percentage of the glomerular and cerebral areas occupied by fat was greater with fat embolism combined with pulmonary contusion than with fat embolism alone (p = 0.0001 and p = 0.01, respectively). (ABSTRACT TRUNCATED)

Dynamics of the inducing signal for the SOS regulatory system in Escherichia coli after ultraviolet irradiation.

SOS response in Escherichia coli is induced by various DNA-damaging treatments, for example by ultraviolet irradiation, to help a cell to recover from the damage. During induction of the SOS regulatory system, generation of the inducing signal for the system is the early step. In the present study a model for quantitative description of the signal dynamics is developed. We derive the inducing signal, in terms of concentration of single-stranded DNA, as a function of time since the moment of ultraviolet irradiation. Simulation of the signal level after irradiation with two doses of 5 and 20 J m-2 is presented. This provides quantitative description of the event that controls various cellular physiological reactions induced in the course of the SOS response. The dynamics of the signal level are then used as an input for a dynamical equation description of the SOS regulatory system that we proposed earlier. This allows for a quantitative analysis of the subsequent step in the SOS induction: cleavage of LexA protein, a negative regulator of the SOS system. The model is verified against available experimental data for LexA protein level in ultraviolet radiation-induced Escherichia coli cells.

Induction of the SOS Response in Ultraviolet-Irradiated Escherichia coli Analyzed by Dynamics of LexA, RecA and SulA Proteins.

The SOS response in Escherichia coli is induced after DNA-damaging treatments including ultraviolet light. Regulation of the SOS response is accomplished through specific interaction of the two SOS regulator proteins, LexA and RecA. In ultraviolet light-treated cells, nucleotide excision repair is the major system that removes the induced lesions from the DNA. Here, induction of the SOS response in Escherichia coli with normal and impaired excision repair function is studied by simulation of intracellular levels of regulatory LexA and RecA proteins, and SulA protein. SulA protein is responsible for SOS-inducible cell division inhibition. Results of the simulations show that nucleotide excision repair influences time-courses of LexA, RecA and SulA induction by modulating the dynamics of RecA protein distribution between its normal and SOS-activated forms.

Muscle perfusion after intramedullary nailing of the canine tibia.

BACKGROUND: Intramedullary nailing with and without reaming leads to a reduction in cortical bone blood flow. The repair of the devascularized bone is mediated principally by the surrounding soft-tissue envelope. The objective of this study was to determine the effect on muscle blood flow of reamed and unreamed intramedullary nailing techniques. METHODS: Midshaft tibial osteotomies to create a 2.5-cm segment of devascularized tibial cortex were performed in 19 adult canines. The tibia was stabilized with a locked intramedullary nail without reaming in 9 animals and with intramedullary reaming in 10 animals. In the unreamed group, the tibia was stabilized with a loosely fitting (n = 4) or a tightly fitting (n = 5) locked nail. In the reamed group, limited reaming (n = 5) or standard reaming (n = 5) was performed. Muscle perfusion was measured in the anterior compartment musculature of the hind-limb using laser Doppler flowmetry. RESULTS: Overall muscle perfusion was greater in the reamed group than in the unreamed group at the conclusion of the nailing procedure (p = 0.0001) and at 5 weeks (p = 0.0008) and 11 weeks after nailing (p = 0.001). The degree of canal fit of the intramedullary nails and the extent of reaming before nail insertion did not further influence muscle circulation. CONCLUSION: The results of this study demonstrate that in the presence of an intact soft-tissue envelope, intramedullary reaming of the canine tibia has a major effect on increasing the circulation to the surrounding muscles. The increased extraosseous circulation may have implications for fracture healing.

Effect of limited and standard reaming on cortical bone blood flow and early strength of union following segmental fracture.

OBJECTIVE: To quantitatively determine the extent to which limited and standard intramedullary reaming disrupts cortical circulation and to evaluate the effect on the biomechanical properties of the united fracture. DESIGN: Midshaft tibial osteotomies to create a 2.5-centimeter segment of diaphyseal bone were performed in ten adult dogs. Before insertion of a locked intramedullary nail, the tibia was reamed to either 7.0 millimeters (n = 5) or 9.0 millimeters (n = 5). Blood flow was measured using laser Doppler flowmetry during the nailing procedure and at eleven weeks postnailing. Bending stiffness and load to failure were determined for each healed tibia. RESULTS: Tibial blood flow was reduced for the limited and the standard ream groups by 63 percent (p = 0.002) and 83 percent (p = 0.0008), respectively. After canal reaming, perfusion was reduced to a greater extent in the standard ream group (p = 0.009). At eleven weeks postnailing, tibial perfusion increased to the same levels in both groups (p = 0.43) and returned to base-line values. Bending stiffness and load to failure were reduced after limited reaming (p = 0.002, p = 0.003) and standard reaming (p = 0.01, p = 0.002) were performed. Stiffness and load to failure were reduced to the same extent in both groups (p = 0.12, p = 0.25). CONCLUSIONS: Both limited reaming and standard reaming negatively affect diaphyseal cortical circulation. Limited reaming spares cortical perfusion compared with standard reaming at the time of nail insertion. No long-term advantage for limited reaming was demonstrated. Limited reaming may be advantageous acutely for the stabilization of tibial fractures in which the circulation is already compromised.

Cortical bone blood flow in loose and tight fitting locked unreamed intramedullary nailing: a canine segmental tibia fracture model.

OBJECTIVES: To quantitatively determine the extent to which loose and tight fitting unreamed, locked intramedullary nails devascularize cortical bone and to determine their effect on early strength of union. DESIGN: A 2.5-centimeter segment of devascularized diaphyseal bone was created in the tibiae of twelve skeletally mature mongrel dogs by means of two standardized transverse osteotomies. Stabilization of the tibia was achieved with either a 5.0-millimeter (n = 6) or a 6.5-millimeter (n = 6) unreamed, locked intramedullary nail. Bone blood flow was assessed using laser Doppler flowmetry. Bending stiffness and load to failure were determined for each healed tibia. RESULTS: At the conclusion of the nailing procedure, the overall tibial blood flow was reduced by 58 percent and 72 percent for the 5.0-millimeter and 6.5-millimeter nail groups, respectively (p = 0.001, p = 0.00004). Perfusion was reduced to a greater extent in the tightly fitting nail group (p = 0.017). At eleven weeks postnailing, cortical perfusion increased in both the 5.0-millimeter and the 6.5-millimeter nail groups (p = 0.005, p = 0.002, respectively). Perfusion increased to a higher level in the loosely fitting nail group (p = 0.007). Biomechanical properties of the healed tibiae, including bending stiffness in two planes and load to failure, were similar in the two experimental groups (p = 0.42, p = 0.09, p = 0.34). DISCUSSION: Our results demonstrate that a loose fitting nail spared cortical perfusion at the time of nail insertion more than did a canal filling nail and allowed more complete cortical reperfusion at eleven weeks postnailing. The results of this study have implications for the treatment of severe tibial shaft fractures in which the blood supply is significantly compromised.