Comparison of Tetrahymena pyriformis toxicity based on hydrophobicity, polarity, ionization and reactivity of class-based compounds

A toxicity data set containing the toxicities of 970 hydrophobic, polar and ionizable, nitro substituted and α,β-unsaturated compounds to Tetrahymena pyriformis was classified into different groups based on the structure and substituted functional groups. Polar, ionizable and reactive compounds exhibit greater toxicity as compared with the non-polar hydrophobic compounds. Step-by-step analysis was carried out between the toxicity and descriptors representing hydrophobicity, polarity/polarizability, ionization and reactivity of compounds. Significant relationships were developed between the toxicity and these descriptors for the compounds. The models developed are simple, interpretable and transparent, using a small number of descriptors that may reflect the interactions of chemicals with the biological macromolecules at the target sites. Hydrophobic parameter log P reflects bio-uptake process compounds. Polarity/polarizability descriptor S reflects the interaction of hydrophilic residues of polar chemicals with biological macromolecules. The fractions of ionized (F (i)) and neutral (F (0)) forms calculated from pK (a) reflect the interactions of ionizable compounds with the macromolecules and effect of ionization of ionizable compounds on the bio-uptake process, respectively. A successful single model was developed by using the descriptors log P, S, F (i) and log F (0) for non-polar, polar and ionizable compounds.

Investigation of the roles of T6SS genes in motility, biofilm formation, and extracellular protease Asp production in Vibrio alginolyticus with modified Gateway-compatible plasmids

AIMS

The aims of this study were to create and evaluate the Gateway-compatible plasmids for investigating the function of genes in Vibrio alginolyticus and other Gram-negative bacteria.

METHODS AND RESULTS

In this study, Gateway-compatible plasmids were successfully constructed for rapid and comprehensive function analysis of genes. Taking advantage of these plasmids, the in-frame deletion mutant strains and their complemented strains of five T6SS genes, including dotU1, VEPGS_0008, VEPGS_0011, hcp2 and ppkA2, were obtained. The results illustrated that all the mutant strains showed no significant effects on extracellular protease production, expression of Hcp1, and biofilm formation when compared to the wild-type strain, but in-frame deletion of VEPGS_0008 resulted in obvious biofilm reduction and the complemented strain restored to the level of the wild-type strain. Besides, in-frame deletion of dotU1, VEPGS_0008 and ppkA2 abolished the swarming ability.

CONCLUSIONS

A set of Gateway-compatible vectors for internal insertion, in-frame deletion and complementation of the target genes is constructed to facilitate the general and rapid function analysis of genes involved in T6SS in Vibrio alginolyticus.

SIGNIFICANCE AND IMPACT OF THE STUDY

The modified Gateway-compatible plasmids greatly facilitate the high-throughput and convenient function analysis of the unidentified genes.

Connection of edge states to bulk topological invariance in a quantum spin Hall state

We propose a topological understanding of general characteristics of edge states in a quantum spin Hall phase without considering any symmetries. It follows from the requirement of gauge invariance that either the energy gap or the gap in the spectrum of the projected spin operator needs to close on the sample edges. Based upon the Kane-Mele model with a uniform Zeeman field and a smooth confining potential near the sample boundaries, we demonstrate the existence of gapless edge states in the absence of time-reversal symmetry and their robust properties against impurities. These gapless edge states are protected by the band topology alone, rather than any symmetries.

A honeycomb lattice model simulating the surface states of topological insulators

A honeycomb lattice model exhibiting the quantum spin-Hall effect is proposed, where the low-energy properties of the electrons are mainly determined by the energy spectrum in the vicinity of the Γ point, for suitable parameters. The nontrivial topology of the energy bands is revealed by calculating the Chern numbers, Berry curvature distribution, and edge state spectrum. We further show that in the continuum limit, the model Hamiltonian is equivalent to the effective model for the surface states in thin films of three-dimensional topological insulators. As a consequence, this lattice model provides a useful tool for numerical simulation of the physical properties of the surface states.

Time-reversal-symmetry-broken quantum spin Hall effect

The quantum spin Hall (QSH) state of matter is usually considered to be protected by time-reversal (TR) symmetry. We investigate the fate of the QSH effect in the presence of the Rashba spin-orbit coupling and an exchange field, which break both inversion and TR symmetries. It is found that the QSH state characterized by nonzero spin Chern numbers C(±) = ±1 persists when the TR symmetry is broken. A topological phase transition from the TR-symmetry-broken QSH phase to a quantum anomalous Hall phase occurs at a critical exchange field, where the bulk band gap just closes. It is also shown that the transition from the TR-symmetry-broken QSH phase to an ordinary insulator state cannot happen without closing the band gap.

Somatic cell cryopreservation and protoplast regeneration of important disease-resistant wild riceOryza meyeriana Baill

Oryza meyeriana Baill is one of the three wild rice species found in Chiia.O. mcyeriana possesses valuable characteristics but is reluctant in cell culturein vitro. In a series of experiments, callus with no regeneration ability was induced from young panicle ofO. meyeriana. The callus was subcultured and propagated. Embryogenic cell clones were obtained after cryopreswation. Suspension cultures were established and protoplasts were isolated and regenerated into plants. Results of artificial inoculation ofXanthomonas campestris pv.Oryzae showed that the strong resistance did not change in the regenerated plants. The development of protoplast-to-plant system is an important progress towards utilization ofO. meyeriana via cellular engineering. The experiments demonstrated that cryopreservation of plant calli was a new way to obtain embryogenic cell line.

Fractional quantum Hall effect in the absence of Landau levels

It is well known that the topological phenomena with fractional excitations, the fractional quantum Hall effect, will emerge when electrons move in Landau levels. Here we show the theoretical discovery of the fractional quantum Hall effect in the absence of Landau levels in an interacting fermion model. The non-interacting part of our Hamiltonian is the recently proposed topologically non-trivial flat-band model on a checkerboard lattice. In the presence of nearest-neighbouring repulsion, we find that at 1/3 filling, the Fermi-liquid state is unstable towards the fractional quantum Hall effect. At 1/5 filling, however, a next-nearest-neighbouring repulsion is needed for the occurrence of the 1/5 fractional quantum Hall effect when nearest-neighbouring repulsion is not too strong. We demonstrate the characteristic features of these novel states and determine the corresponding phase diagram.

Thermoelectric effect in single-molecule-magnet junctions

We study the spin-dependent thermoelectric transport through a single-molecule-magnet junction in the sequential tunneling regime. It is found that the intrinsic magnetic anisotropy of the single-molecule magnet can lead to gate-voltage-dependent oscillations of charge thermopower and a large violation of the Wiedeman-Franz law. More interestingly, the spin-Seebeck coefficient is shown to be greater than the charge-Seebeck coefficient, and a pure spin thermopower or/and a pure spin current can be obtained by tuning only the gate voltage. It needs neither an external magnetic field or irradiation of circularly polarized light on the molecule nor ferromagnetic leads to realize these interesting effects, indicating the powerful prospect of single-molecule-magnet applications in spintronic devices.

Electrical properties in magnetic field of macroscopic carbon nanotube objects

The electrical properties including zero-field resistivity, magnetoresistance and current-voltage (I-V) curves of macroscopic carbon nanotube (CNT) objects (yarns, bundles, films, and networks) have been measured. The macroscopic CNT objects exhibit semiconductor-like behaviors. Under the magnetic field applied perpendicular to the plane or axis of the Macroscopic CNT objects, a pronounced negative magnetoresistance have been observed. Due to the aligned, close-packed structure of MWNT yarn, its MR reach as high as -17% at 9 T. The I-V curves of the MWNT network exhibit a linear relationship even at low temperature, but the other samples exhibit a nonlinear relationship, indicating the effect of morphology and defects of CNTs in macroscopic CNT objects.

The effect of spin mixing on the quantum Hall effect in graphene

On the basis of a tight-binding model, we study numerically the effect of Rashba spin-orbit coupling on the quantum Hall effect in graphene. It is found that the spin-orbit coupling can open a gap in the energy spectrum of the counterpropagating edge states in the ν = 0 plateau region, while the edge states in other plateau regions remain gapless. In the presence of disorder, the energy spectrum in the ν = 0 plateau region shows the feature of level repulsion, an indication of switching on of backward scattering and localization of the edge states. This result may explain the insulator-like behavior near the Dirac points observed in experiments at low temperatures.

Formation and temperature evolution of correlated polarons in colossal magnetoresistive manganites

We investigate the temperature dependence of charge ordered clusters in manganites. In terms of an approximate treatment of the half-filled spinless Holstein model incorporating the double exchange effect and nearest-neighbor Coulomb interactions, we find that charge ordering and polaronic states appear simultaneously which naturally defines a correlated polaron state. Without the double exchange, the temperature evolution of the charge (polaron) ordering parameter exhibits a broad peak structure only in the strongly correlated quasiadiabatic regime. Including the double exchange, the peak becomes sharper and is observed both in the quasiadiabatic and antiadiabatic regimes. The peak structure in the quasiadiabatic regime provides an explanation for the temperature dependence of the polaron correlation in nanoscale charge ordered polaron clusters observed in the manganites with intermediate to narrow bandwidths.

Analysis of risk factors associated with outcomes in road traffic injury patients with acute lung injury

Over 50% of road traffic injury (RTI) patients experience post-traumatic acute lung injury (ALI) and it is, therefore, extremely important to identify the risk factors related to the poor outcomes associated with ALI in RTI populations. This study evaluated 19 potential risk factors associated with the outcomes of ALI in 366 RTI patients. They were divided into two groups: a 'favourable outcomes group' and an 'unfavourable outcomes group'. The results indicated that the Acute Physiology and Chronic Health Evaluation II (APACHE II) score and the presence of gastrointestinal haemorrhage may help predict the outcomes of ALI in the early post-trauma phase of treatment. The duration of trauma and sepsis were shown to impact strongly on both the short- and long-term outcomes of ALI. Age (> 65 years) and disseminated intravascular coagulation in the early RTI phase were also independent risk factors for a poorer short- and long-term outcome in ALI.

Realizing and detecting the quantum Hall effect without landau levels by using ultracold atoms

We design an ingenious scheme to realize Haldane's quantum Hall model without Landau levels by using ultracold atoms trapped in an optical lattice. Three standing-wave laser beams are used to construct a wanted honeycomb lattice, where different on site energies in two sublattices required in the model can be implemented through tuning the phase of one laser beam. The staggered magnetic field is generated from the light-induced Berry phase. Moreover, we establish a relation between the Hall conductivity and the atomic density, enabling us to detect the Chern number with the typical density-profile-measurement technique.

The impact of clinical risk factors in the conversion from acute lung injury to acute respiratory distress syndrome in severe multiple trauma patients

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are different stages of the same disease, the aggravated stage of ALI leading to ARDS. Patients with ARDS have higher hospital mortality rates and reduced long-term pulmonary function and quality of life. It is, therefore, important to prevent ALI converting to ARDS. This study evaluated 17 risk factors potentially associated with the conversion from ALI to ARDS in severe multiple trauma. The results indicate that the impact of pulmonary contusion, APACHE II score, gastrointestinal haemorrhage and disseminated intravascular coagulation may help to predict conversion from ALI to ARDS in the early phase after multiple-trauma injury. Trauma duration, in particular, strongly impacted the short- and long-term development of ALI. Being elderly (aged > or = 65 years) and undergoing multiple blood transfusions in the early phase were independent risk factors correlated with secondary sepsis, deterioration of pulmonary function and transfusion-related acute lung injury due to early multiple fluid resuscitation.

Crocetin improves the insulin resistance induced by high-fat diet in rats

BACKGROUND AND PURPOSE

The amelioration of insulin resistance by treatment with crocetin is closely related to the hypolipidaemic effect. The present study is designed to clarify the insulin-sensitizing mechanism of crocetin by elucidating the mechanism of regulation of lipid metabolism by crocetin.

EXPERIMENTAL APPROACH

Rats given a high-fat diet were treated with crocetin for 6 weeks before hyperinsulinaemic-euglycaemic clamp. 14C-palmitate was used as tracer to track the fate of non-esterified fatty acids or as substrate to measure beta-oxidation rate. Triglyceride clearance in plasma and lipoprotein lipase activity in tissues were tested. Content of lipids in plasma and tissues was determined. Real-time PCR was used to assay the level of mRNA from genes involved in non-esterified fatty acid and triglyceride uptake and oxidation.

KEY RESULTS

Crocetin prevented high-fat-diet induced insulin resistance (increased clamp glucose infusion rate), raised hepatic non-esterified fatty acid uptake and oxidation, accelerated triglyceride clearance in plasma, enhanced lipoprotein lipase activity in liver, and reduced the accumulation of detrimental lipids (DAG and long-chain acyl CoA) in liver and muscle. Genes involved in hepatic lipid metabolism which are regulated by peroxisome proliferator-activated receptor-alpha, were modulated to accelerate lipid uptake and oxidation.

CONCLUSIONS AND IMPLICATIONS

Through regulating genes involved in lipid metabolism, crocetin accelerated hepatic uptake and oxidation of non-esterified fatty acid and triglyceride, and reduced lipid availability to muscle, thus decreasing lipid accumulation in muscle and liver, and consequently improving sensitivity to insulin.

Broken-symmetry states of Dirac fermions in graphene with a partially filled high Landau level

We report on numerical study of the Dirac fermions in partially filled N=3 Landau level (LL) in graphene. At half-filling, the equal-time density-density correlation function displays sharp peaks at nonzero wave vectors +/-q*. Finite-size scaling shows that the peak value grows with electron number and diverges in the thermodynamic limit, which suggests an instability toward a charge density wave. A symmetry broken stripe phase is formed at large system size limit, which is robust against perturbation from disorder scattering. Such a quantum phase is experimentally observable through transport measurements. Associated with the special wave functions of the Dirac LL, both stripe and bubble phases become possible candidates for the ground state of the Dirac fermions in graphene with lower filling factors in the N=3 LL.

A normalized adaptive training of recurrent neural networks with augmented error gradient

For training algorithms of recurrent neural networks (RNN), convergent speed and training error are always two contradictory performances. In this letter, we propose a normalized adaptive recurrent learning (NARL) to obtain a tradeoff between transient and steady-state response. An augmented term is added to error gradient to exactly model the derivative of cost function with respect to hidden layer weight. The influence of the induced gain of activation function on training stability is also taken into consideration. Moreover, adaptive learning rate is employed to improve the robustness of the gradient training. Finally, computer simulations of a model prediction problem are synthesized to give comparisons between NARL and conventional normalized real-time recurrent learning (N-RTRL).

Changes in lip 1 year after modified Millard repair

The aim of this study was to observe changes in the lip 1 year after performing a modified Millard cleft lip repair, by comparing the preoperative and 1-year follow-up appearance of the lip. Twenty-three patients with a unilateral complete cleft were photographed by a standardized method before repair, 7 days after surgery and 12 months after surgery. Lips on the cleft side were measured and compared with the opposite side. Possible results were: equal, longer and shorter. There was no linear correlation between the preoperative and 1-year postoperative appearance of the lip, but there was a linear correlation in lip height between the 7-day and 12-month postoperative results. No matter how severe the initial deformity, primary repair of the cleft lip is crucial in maintaining labial symmetry 1 year after operation.

Odd-integer quantum Hall effect in graphene: interaction and disorder effects

We study the competition between the long-range Coulomb interaction, disorder scattering, and lattice effects in the integer quantum Hall effect (IQHE) in graphene. By direct transport calculations, both nu=1 and nu=3 IQHE states are revealed in the lowest two Dirac Landau levels. However, the critical disorder strength above which the nu=3 IQHE is destroyed is much smaller than that for the nu=1 IQHE, which may explain the absence of a nu=3 plateau in recent experiments. While the excitation spectrum in the IQHE phase is gapless within numerical finite-size analysis, we do find and determine a mobility gap, which characterizes the energy scale of the stability of the IQHE. Furthermore, we demonstrate that the nu=1 IQHE state is a Dirac valley and sublattice polarized Ising pseudospin ferromagnet, while the nu=3 state is an xy plane polarized pseudospin ferromagnet.

Effect of pioglitazone on the expression of inflammatory cytokines in attenuating rat cardiomyocyte hypertrophy

Pioglitazone, one of the synthetic peroxisome proliferator-activated receptor (PPARgamma) agonists, has been found to inhibit inflammatory response. However, it is not known yet whether the preventive effect of pioglitazone on cardiac hypertrophy is related to its antiinflammatory function. The objective of this study was to investigate the role of pioglitazone in attenuation of cardiac hypertrophy and its relation to the inhibitory effect on the inflammatory cytokine expression in cultured neonatal rat cardiomyocytes. The mRNA expression of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), interleukin (IL)-1beta, IL-6, and PPARgamma was measured by using RT-PCR. Cardiomyocyte hypertrophy was induced by stimulating angiotensin II (Ang II) and evaluated both by measuring surface area of cardiac myocyte and 3H-leucine incorporation. The expressions of IL-1beta, IL-6, ANP, and BNP were significantly enhanced, whereas that of PPARgamma was significantly reduced in Ang II-induced hypertrophic cardiomyocytes. Pioglitazone decreased cardiac myocyte surface area and inhibited 3H-leucine incorporation into cardiomyocytes. Furthermore, pioglitazone upregulated the suppressed expression of PPARgamma and attenuated the increased IL-1beta and IL-6 expression. The effect of pioglitazone might be associated with PPARgamma activation and the consequent antiinflammatory function in prevention and treatment of cardiac hypertrophy.

Quantum spin-Hall effect and topologically invariant Chern numbers

We present a topological description of the quantum spin-Hall effect (QSHE) in a two-dimensional electron system on a honeycomb lattice with both intrinsic and Rashba spin-orbit couplings. We show that the topology of the band insulator can be characterized by a 2 x 2 matrix of first Chern integers. The nontrivial QSHE phase is identified by the nonzero diagonal matrix elements of the Chern number matrix (CNM). A spin Chern number is derived from the CNM, which is conserved in the presence of finite disorder scattering and spin nonconserving Rashba coupling. By using the Laughlin gedanken experiment, we numerically calculate the spin polarization and spin transfer rate of the conducting edge states and determine a phase diagram for the QSHE.