Influence of Lifshitz Transition on the Intrinsic Resistivity of Cu2N Monolayer.

The Lifshitz transition (LT), a topological structure transition of Fermi surfaces, can induce various intricate physical properties in metallic materials. In this study, through first-principles calculations, we explore the nontrivial effect of the LT on the intrinsic resistivity of the Cu2N monolayer arising from electron-phonon (el-ph) scattering. We find that when the LT is induced by electron doping, the multibranch Fermi surface simplifies into a single-band profile. Such an LT leads to a decoupling of low-frequency flexural phonons from el-ph scattering due to mirror symmetry. Consequently, the resistivity of the Cu2N monolayer at room temperature significantly decreases, approaching that of slightly doped graphene, and highlighting the Cu2N monolayer as a highly conductive two-dimensional metal. Moreover, this LT can bring about a nonlinear temperature dependence of the intrinsic resistivity at a high temperature.

Identification of Genetic Loci for Sugarcane Leaf Angle at Different Developmental Stages by Genome-Wide Association Study.

Sugarcane (Saccharum spp.) is an efficient crop mainly used for sugar and bioethanol production. High yield and high sucrose of sugarcane are always the fundamental demands in sugarcane growth worldwide. Leaf angle and size of sugarcane can be attributed to planting density, which was associated with yield. In this study, we performed genome-wide association studies (GWAS) with a panel of 216 sugarcane core parents and their derived lines (natural population) to determine the genetic basis of leaf angle and key candidate genes with +2, +3, and +4 leaf at the seedling, elongation, and mature stages. A total of 288 significantly associated loci of sugarcane leaf angle at different developmental stages (eight phenotypes) were identified by GWAS with 4,027,298 high-quality SNP markers. Among them, one key locus and 11 loci were identified in all three stages and two stages, respectively. An InDel marker (SNP Ss6A_102766953) linked to narrow leaf angle was obtained. Overall, 4,089 genes were located in the confidence interval of significant loci, among which 3,892 genes were functionally annotated. Finally, 13 core parents and their derivatives tagged with SNPs were selected for marker-assisted selection (MAS). These candidate genes are mainly related to MYB transcription factors, auxin response factors, serine/threonine protein kinases, etc. They are directly or indirectly associated with leaf angle in sugarcane. This research provided a large number of novel genetic resources for the improvement of leaf angles and simultaneously to high yield and high bioethanol production.

Electron-phonon scattering limited hole mobility at room temperature in a MoS2 monolayer: first-principles calculations.

Based on first-principles calculations and iterative solution of the Boltzmann transport equation, we theoretically study the room temperature mobility (RTM) of a valence band hole in a MoS2 monolayer (ML) limited by electron-phonon (e-ph) scattering. The hole mobility obtained by us is 26.0 cm2 V-1 s-1 at 300 K. This is a value much closer to the experimental result (about 40.0 cm2 V-1 s-1). In contrast, the semi-empirical estimate based on the deformational potential (DP) model in previous literature gave a value of 200.5 cm2 V-1 s-1, far away from the experimental data. By a detailed analysis, we find that unlike the case of conduction band electrons, the intervalley scattering realized by longitudinal acoustic (LA) phonons plays a dominant role in influencing the hole mobility. And this is the main reason for the DP model failing to give a quantitative estimate of the hole RTM in MoS2-ML.

Effects of uniaxial tensile strain on the electron-phonon scattering limited carrier mobility in an n-type monolayer MoS2 at room temperature: first-principles calculations.

In the present work, we theoretically study the strain effect on the room temperature mobility (RTM) of a n-type Monolayer MoS2 limited by electron-phonon (e-ph) scattering. Our numerical results indicate that the RTM along zigzag direction of such a 2D material can be efficiently modulated by a uniaxial tensile strain. Such an RTM, denoted as [Formula: see text], has a sizable reduction (enhancement) as a moderate tensile strain is applied in a parallel (perpendicular) direction. For example, when the strain strength amounts to 7%, [Formula: see text] the two distinct cases of the strain applied in x and y  directions differ from each other by roughly two times. In contrast, the RTM in armchair direction is not so sensitive to a tensile strain. The underlying mechanism for such a strain effect on the mobility is then analysed in depth. Our results are obtained completely on the level of first-principles calculations, free from any empirical simplifications. Therefore, our above findings provide reliable and detailed information for experimentally manipulating the RTM of a n-type monolayer MoS2 by simply stretching the sample.

Magnetic field induced metal-insulator transition in single nodal ring topological semimetals.

Our theoretical investigation indicates that an applied magnetic field can open a gap between the conduction and valence bands of a nodal line semimetal (NLSM), though it is a kind of gapless material in the absence of a magnetic field. The emerging bandgap depends sensitively on the strength and orientation of the magnetic field which implies a tunable and large anisotropy of magnetoresistance in such kinds of topological materials. Following such a theoretical finding, we predict that in some candidates of NSLMs with a single nodal ring, such as the materials of CaP3 family, a transition between metallic and insulating states driven by a magnetic field is possibly observed experimentally. Consequently, a magnetic field can be viewed as a novel mechanism for metal-insulator transition of solid materials, in additional to the well-known conventional ones such as the Anderson and Mott transitions.

Simulation on the electronic wave packet cyclotron motion in a Weyl semimetal slab.

We perform a numerical simulation on the time evolution of an electronic wave packet in a Weyl semimetal (WSM) slab driven by a magnetic field. We find that the evolution trajectory of the wave packet depends sensitively on its initial spin state. Only with initial spin state identical to that of the Fermi arc state at the surface it localized, does the wave packet evolution demonstrate the characteristic cyclotron orbit of WSM previously predicted from a semiclassical viewpoint. By analyzing the eigen-expansion of the electronic wave packet, we find the chiral Landau levels (LLs) of the WSM slab, as ingredients of the wave packet, to be responsible for establishing the characteristic WSM cyclotron orbit. In contrast, the nonchiral LLs contribute irregular oscillations to the wave packet evolution, going against the formation of a well-defined cyclotron orbit. In addition, the tilted magnetic field does not affect the motion of the electronic wave packet along the Fermi arcs in the momentum space. It does, however, alter the evolution trajectory of the electronic wave packet in real space and spin space. Finally, the energy disalignment of the Weyl nodes results in a 3D cyclotron orbit in real space.

Cerebral Syphilitic Gumma Misdiagnosed as a Malignant Brain Tumor.

Syphilitic gumma involvement of the central nervous system is extremely rare and frequently misdiagnosed. The authors report a patient of a cerebral syphilitic gumma resembling a malignant brain tumor in a 62-year-old male. He was first suspected of a malignant brain tumor, but the pathological diagnosis was cerebral syphilitic gumma. This patient with unusual findings illustrates the clinical manifestations, imaging, and therapeutic aspects of cerebral syphilitic gumma.

A Comparative Study of Contemporary Color Tongue Image Extraction Methods Based on HSI.

Tongue image with coating is of important clinical diagnostic meaning, but traditional tongue image extraction method is not competent for extraction of tongue image with thick coating. In this paper, a novel method is suggested, which applies multiobjective greedy rules and makes fusion of color and space information in order to extract tongue image accurately. A comparative study of several contemporary tongue image extraction methods is also made from the aspects of accuracy and efficiency. As the experimental results show, geodesic active contour is quite slow and not accurate, the other 3 methods achieve fairly good segmentation results except in the case of the tongue with thick coating, our method achieves ideal segmentation results whatever types of tongue images are, and efficiency of our method is acceptable for the application of quantitative check of tongue image.

[Study on discrimination mode of cold and hot properties of traditional Chinese medicines based on biological effects].

OBJECTIVE: To observe the effect of cold or hot properties of traditional Chinese medicines (TCM) on biological effect indexes, and analyze the contribution of variables on cold or hot properties, in order to preliminarily establish the discrimination mode for the biological effects of cold or hot properties. METHOD: Rats were randomly divided into the blank control group, cold TCM groups (Coptidis Rhizoma, Scutellariae Radix, Phellodendri Cortex, Gardeniae Fructus, Sophorae Flavescentis Radix and Gentianae Radix) and hot TCM groups (Aconiti Lateralis Preparata Radix, Zingiberis Rhizoma, Alpiniae Officinarum Rhizoma, Zanthoxyli Pericarpium, Cinnamomi Cortex and Evodiae Fructus), and orally administered with 10 mL x kg(-1) of corresponding TCM water decoctions for 30 d, twice a day. Altogether 53 biological effect indexes correlated to cold or hot properties of traditional Chinese medicines were founded by searching literatures. The data warehouse were established by using data-mining software Clementine12.0. Data of the blank control group, cold TCM groups (Coptidis Rhizoma, Phellodendri Cortex, Gardeniae Fructus, Sophorae Flavescentis Radix, Gentianae Radix) and hot TCM groups (Aconiti Lateralis Preparata Radix, Zingiberis Rhizoma, Alpiniae Officinarum Rhizoma, Zanthoxyli Pericarpium, Cinnamomi Cortex) were selected into a training set. C5.0 algorithm and C&R classification and regression algorithm were adopted to define the importance of variable, create the decision trees, and test hot or cold properties of Evodiae Fructus and Scutellariae Radix. RESULT: According to C&R classification and regression algorithm, SDH activity of livers was the most important hot or cold property, with the significance closed to 30%. It was followed by triglyceride, liver Na' -K' -ATPase enzyme, muscle glycogen and platelet distribution width, with the accuracy up to 97.39% in models. C5.0 algorithm showed that liver SDH activity was the most important hot or cold property, with the significance closed to 40%. It was followed by triglyceride, GOT, muscle glycogen and liver Na(+)-K(+)-ATPase enzyme, with the accuracy up to 98.26% in models. The possibilities that Evodiae Fructus is in hot property and Scutellariae Radix is in cold property were 100. 00% and 77.78% by using both C&R classification and regression algorithm and C5.0 algorithm. CONCLUSION: The SDH activity of liver is the most important biological effect index to distinguish cold and hot properties of TCMs. The discrimination pathway or mode of cold and hot properties is closely related to energy metabolism.

[A new method of automatic analysis of tongue deviation using self-correction].

The article analyzes the old analysis method of tongue deviation and introduces a new analysis method of it with self-correction avoiding the shortcomings of the old method. In this article, comparisons and analyses are made to current central axis extraction methods, and the facts proved that these methods were not suitable for central axis extraction of tongue images. To overcome the shortcoming that the old method utilized area symmetry to extract central axis so that it would lead to a failure to find central axis, we introduced a kind of shape symmetry analysis method to extract the central axis. This method was capable of correcting the edge of tongue root automatically, and it improved the accuracy of central axis extraction. In additional, in this article, a kind of mouth corner analysis method by analysis of variational hue of tongue images was introduced. In the experiment for comparison, this method was more accurate than the old one and its efficiency was higher than that of the old one.

One-step template-free synthesis of monoporous polymer microspheres with uniform sizes via microwave-mediated dispersion polymerization.

One-step facile synthesis of monoporous polymer microspheres via microwave-controlled dispersion polymerization is introduced. This template-free method employing the dispersion polymerization of styrene under microwave irradiation induces directly the formation of uniform monoporous polymer microspheres, with controllable morphologies and sizes, which can be tuned by simply adjusting parameters for the synthesis. A comparison to conventional heating indicates that microwave irradiation plays a vital role in the formation of this novel morphology.

[Clinical efficacy and safety of sublingual immunotherapy using standardized Dermatophagoides farinae extract for children with combined allergic rhinitis and asthma syndrome].

OBJECTIVE: To study the clinical efficacy of sublingual immunotherapy using standardized Dermatophagoides farinae extract for children with combined allergic rhinitis and asthma syndrome. METHODS: Fifty-two children, from 4 to 14 years of age, with mite-sensitive combined allergic rhinitis and asthma syndrome were treated sublingually with standardized Dermatophagoides farinae extract. The clinical efficacy was evaluated by monthly follow-up visits. After treatment for 1 or 2 years using the standardized Dermatophagoides farinae extract, the asthma and rhinitis symptom scores, medication scores and adverse reactions before and after treatment were evaluated. SPSS 17.0 software was used to analyze the data. RESULTS: The allergic asthma symptom scores before treatment during the day were 3.22 ± 0.66 and at night 2.05 ± 0.57. After 1 year of treatment, the day and night scores (1.68 ± 0.61, 0.94 ± 0.32) respectively, were decreased significantly (q values were 15.25 and 13.78 respectively, all P < 0.01). After 2 years of treatment, the scores (0.61 ± 0.28, 0.43 ± 0.13) were also decreased significantly (q values were 10.29 and 6.07 respectively, all P < 0.01). The allergic rhinitis symptom scores and medication scores were 2.34 ± 0.59 and 3.09 ± 1.01 respectively before treatment and 1.21 ± 0.46 and 1.89 ± 0.64 after 1 year of treatment. The differences were significant (q values were 15.48 and 18.61 respectively, all P < 0.01). The allergic rhinitis symptom scores and medication scores were 1.02 ± 0.37 and 1.49 ± 0.38 after 2 years of treatment. There was no significant difference between 2 years of treatment and 1 year of treatment (q values were 2.53 and 2.78 respectively, all P > 0.05). There were no severe adverse events during the treatment, except for mild mouth cavity discomfort. CONCLUSIONS: Sublingual immunotherapy using standardized Dermatophagoides farinae extract is safe and effective in the treatment of children with combined allergic rhinitis and asthma syndrome.

Microwave synthesis of zinc sulfite and porous zinc oxide microrods.

ZnSO(3) microrods with uniform size and shape can be prepared under microwave irradiation at much higher speed than a conventional heating bath, usually in minutes. The annealing of ZnSO(3) microrods produced porous ZnO microrods with pore size between 50-200 nm.