Pressure-Induced Superconductivity up to 9 K in the Quasi-One-Dimensional KMn_{6}Bi_{5}.

The Mn-based superconductor is rare owing to the strong magnetic pair-breaking effect. Here we report on the discovery of pressure-induced superconductivity in KMn_{6}Bi_{5}, which becomes the first ternary Mn-based superconductor. At ambient pressure, the quasi-one-dimensional KMn_{6}Bi_{5} is an antiferromagnetic metal with T_{N}≈75 K. By measuring resistance and ac magnetic susceptibility under hydrostatic pressures up to 14.2 GPa in a cubic anvil cell apparatus, we find that its antiferromagnetic transition can be suppressed completely at a critical pressure of P_{c}≈13 GPa, around which bulk superconductivity emerges and displays a superconducting dome with the maximal T_{c}^{onset}=9.3 K achieved at about 14 GPa. The close proximity of superconductivity to a magnetic instability in the temperature-pressure phase diagram of KMn_{6}Bi_{5} and an unusually large µ_{0}H_{c2}(0) exceeding the Pauli paramagnetic limit suggests an unconventional magnetism-mediated paring mechanism. In contrast to the binary MnP, the flexibility of the crystal structure and chemical compositions in the ternary AMn_{6}Bi_{5} (A=alkali metal) can open a new avenue for finding more Mn-based superconductors.

Survival of itinerant excitations and quantum spin state transitions in YbMgGaO4 with chemical disorder.

A recent focus of quantum spin liquid (QSL) studies is how disorder/randomness in a QSL candidate affects its true magnetic ground state. The ultimate question is whether the QSL survives disorder or the disorder leads to a "spin-liquid-like" state, such as the proposed random-singlet (RS) state. Since disorder is a standard feature of most QSL candidates, this question represents a major challenge for QSL candidates. YbMgGaO4, a triangular lattice antiferromagnet with effective spin-1/2 Yb3+ions, is an ideal system to address this question, since it shows no long-range magnetic ordering with Mg/Ga site disorder. Despite the intensive study, it remains unresolved as to whether YbMgGaO4 is a QSL or in the RS state. Here, through ultralow-temperature thermal conductivity and magnetic torque measurements, plus specific heat and DC magnetization data, we observed a residual κ0/T term and series of quantum spin state transitions in the zero temperature limit for YbMgGaO4. These observations strongly suggest that a QSL state with itinerant excitations and quantum spin fluctuations survives disorder in YbMgGaO4.

Unraveling the Topological Phase of ZrTe_{5} via Magnetoinfrared Spectroscopy.

For materials near the phase boundary between weak and strong topological insulators (TIs), their band topology depends on the band alignment, with the inverted (normal) band corresponding to the strong (weak) TI phase. Here, taking the anisotropic transition-metal pentatelluride ZrTe_{5} as an example, we show that the band inversion manifests itself as a second extremum (band gap) in the layer stacking direction, which can be probed experimentally via magnetoinfrared spectroscopy. Specifically, we find that the band anisotropy of ZrTe_{5} features a slow dispersion in the layer stacking direction, along with an additional set of optical transitions from a band gap next to the Brillouin zone center. Our work identifies ZrTe_{5} as a strong TI at liquid helium temperature and provides a new perspective in determining band inversion in layered topological materials.

Machine-learning-assisted insight into spin ice Dy2Ti2O7.

Complex behavior poses challenges in extracting models from experiment. An example is spin liquid formation in frustrated magnets like Dy2Ti2O7. Understanding has been hindered by issues including disorder, glass formation, and interpretation of scattering data. Here, we use an automated capability to extract model Hamiltonians from data, and to identify different magnetic regimes. This involves training an autoencoder to learn a compressed representation of three-dimensional diffuse scattering, over a wide range of spin Hamiltonians. The autoencoder finds optimal matches according to scattering and heat capacity data and provides confidence intervals. Validation tests indicate that our optimal Hamiltonian accurately predicts temperature and field dependence of both magnetic structure and magnetization, as well as glass formation and irreversibility in Dy2Ti2O7. The autoencoder can also categorize different magnetic behaviors and eliminate background noise and artifacts in raw data. Our methodology is readily applicable to other materials and types of scattering problems.

[Therapeutic effect of burr-hole operation combined with dural inversion and temporalis-periosteal synangiosis for ischemic moyamoya disease of adults].

Objective: To explore the therapeutic effect of burr-hole operation combined with dural inversion and temporalis-periosteal synangiosis for ischemic moyamoya disease of adults. Methods: The burr-hole operation combined with dural inversion and temporalis-periosteal synangiosis was performed on 21 adults with ischemic moyamoya disease since January 2013 in the second hospital of Shandong university.All of the patients were followed up for 3 months to 3 years.Digital subtraction angiogram (DSA) reexamination was performed and the cerebral MR perfusion imaging (PWI) was used to observe the perfusion of cerebral ischemic area before and after operation quantificationally, and the KPS scores before and after the surgery were analysed by the statistics.The clinical symptoms of the 21 patients gradually improved after the operation, there was statistical significance by paired t test of the KPS scores (P<0.001). Results: 19 patients were reexamined by DSA and PWI.The DSA results revealed there was apparent neovascularization in 65 burr-holes of total 72 holes , mainly came from the middle meningeal artery and superficial artery, and there was neovascularization in 33 burr-holes of total 35 holes whose arachnoid was completed, there was no statistical significance by χ(2) test (P>0.05). The revascularization of the ischemic cerebral tissue was obtained through the PWI.The postoperative complications included 1 case of subdural hematoma, 3 cases of postoperative temporary neurological deficits. Conclusion: The burr-hole operation combined with dural inversion and temporalis-periosteal synangiosis was effective, the MR perfusion imaging could assessment the effect exactly, there was no significant difference of neovascularization whether or not opening the arachnoid.

A study of the knowledge, attitudes and practices of Tibetan yak herders with respect to brucellosis.

Background: Little information is available regarding the knowledge, attitudes and practices (KAP) of the owners of yaks in Tibet with respect to brucellosis. Methods: This manuscript reports on the results of a cross-sectional survey using a structured questionnaire investigating the KAP of 317 yak herders from 34 villages in the three main yak-rearing counties of Maizhokunggar, Damxung and Yadong from April to August 2015. Results: Although 60.6% of the respondents had heard of brucellosis, there was an overall low level of knowledge about the disease. Herders did, however, adopt management/husbandry practices which would reduce transmission of the disease to humans and other animals. Multivariable logistic modelling showed that a better knowledge was predicted by age, production system adopted, education level and number of people in a household. Differences in attitudes and practices were predicted by education level, production system and household size. Conclusions: In order to increase the awareness of herders on brucellosis and to reduce the risk of infection in both humans and other animals, public health education campaigns should be developed and offered to livestock owners in Tibet.

Canted magnetic ground state of quarter-doped manganites R 0.75Ca0.25MnO3 (R = Y, Tb, Dy, Ho, and Er).

Polycrystalline samples of the quarter-doped manganites R 0.75Ca0.25MnO3 (R = Y, Tb, Dy, Ho, and Er) were studied by x-ray diffraction and AC/DC susceptibility measurements. All five samples are orthorhombic and exhibit similar magnetic properties: enhanced ferromagnetism below T 1 (∼80 K) and a spin glass (SG) state below T SG (∼30 K). With increasing R 3+ ionic size, both T 1 and T SG generally increase. The single crystal neutron diffraction results on Tb0.75Ca0.25MnO3 revealed that the SG state is mainly composed of a short-range ordered version of a novel canted (i.e. noncollinear) antiferromagnetic spin state. Furthermore, calculations based on the double exchange model for quarter-doped manganites reveal that this new magnetic phase provides a transition state between the ferromagnetic state and the theoretically predicted spin-orthogonal stripe phase.

Quantum Oscillations at Integer and Fractional Landau Level Indices in Single-Crystalline ZrTe5.

A three-dimensional (3D) Dirac semimetal (DS) is an analogue of graphene, but with linear energy dispersion in all (three) momentum directions. 3D DSs have been a fertile playground in discovering novel quantum particles, for example Weyl fermions, in solid state systems. Many 3D DSs were theoretically predicted and experimentally confirmed. We report here the results in exfoliated ZrTe5 thin flakes from the studies of aberration-corrected scanning transmission electron microscopy and low temperature magneto-transport measurements. Several unique results were observed. First, a π Berry phase was obtained from the Landau fan diagram of the Shubnikov-de Haas oscillations in the longitudinal conductivity σxx. Second, the longitudinal resistivity ρxx shows a linear magnetic field dependence in the quantum limit regime. Most surprisingly, quantum oscillations were also observed at fractional Landau level indices N = 5/3 and 7/5, demonstrating strong electron-electron interaction effects in ZrTe5.

[Prevalence and trend of overweight and obesity in children and adolescents in Guangdong province, 2002-2012].

Objective: To investigate the prevalence and trend of overweight and obesity in children and adolescents aged 6-17 years between 2002 and 2012 in Guangdong province. Methods: A total of 7 075 children and adolescents aged 6-17 years were selected in Guangdong for nutritional survey in 2002 and a total of 2 319 children and adolescents aged 6-17 years were selected in nine counties/districts of Guangdong for nutritional survey during 2009-2012 through multi-stage random cluster sampling. The body height and weight of all the children and adolescents were measured. Results: The result of 2009-2012 survey indicated the average prevalence of overweight and obesity in the children and adolescents surveyed were 7.3% and 4.5%, respectively. The prevalence of overweight and obesity were higher in boys (8.9% and 6.5%) than in girls (5.3% and 2.2%), in rural area (9.3% and 5.6%) than in urban area (4.7% and 3.2%). Children and adolescents aged 9-11 years had a higher overweight and obesity rates compared with other age groups. Compared with 2002, except for obesity rate in urban girls, the prevalence of overweight and obesity in children and adolescents obviously increased. The increase rate was higher in rural area than urban area and in boys than in girls. Conclusions: Compared with 2002, the prevalence of overweight and obesity in children and adolescents in Guangdong obviously increased. The prevalence was much higher in boys, those living in rural area and those aged 9-11 years, thus more attention should be paid to them.

Magnetic Ground States of the Rare-Earth Tripod Kagome Lattice Mg_{2}RE_{3}Sb_{3}O_{14} (RE=Gd,Dy,Er).

We present the structural and magnetic properties of a new compound family, Mg_{2}RE_{3}Sb_{3}O_{14} (RE=Gd,Dy,Er), with a hitherto unstudied frustrating lattice, the "tripod kagome" structure. Susceptibility (ac, dc) and specific heat exhibit features that are understood within a simple Luttinger-Tisza-type theory. For RE=Gd, we found long-ranged order (LRO) at 1.65 K, which is consistent with a 120° structure, demonstrating the importance of diople interactions for this 2D Heisenberg system. For RE=Dy, LRO at 0.37 K is related to the "kagome spin ice" physics for a 2D system. This result shows that the tripod kagome structure accelerates the transition to LRO predicted for the related pyrochlore systems. For RE=Er, two transitions, at 80 mK and 2.1 K are observed, suggesting the importance of quantum fluctuations for this putative XY system.

[Cadmium burden and renal dysfunction among residents in cadmium-polluted areas: A 3-year follow-up study].

OBJECTIVE: To investigate dynamic change of cadmium body burden and renal dysfunction among residents living in cadmium-polluted areas. METHODS: From April to July of 2011, the cadmium-polluted areas of northern Guangdong province in China was chosen as the study site. Based on the levels of cadmium pollution in soil and rice, the survey areas were divided into low exposed group (average concentration of cadmium was 0.15-0.40 mg/kg, 0.5-1.0 mg/kg in rice and soil, respectively) and high exposed group (average concentration of cadmium was >0.40 mg/kg, >1.0 mg/kg in rice and soil, respectively). Stratified random sampling and cluster sampling method of epidemiological investigations were carried out among 414 local residents who lived in cadmium exposure areas for more than 15 years, aged above 40, and without occupational cadmium exposure, including 168 and 246 residents in low and high exposed group, respectively. From March to June of 2014, 305 respondents of those who participated in 2011 were successfully traced, including 116 and 189 respondents in low and high exposed group, respectively. We used health questionnaires to acquire their health status. Home-harvested rice and vegetable samples were collected using quartering method for detection of cadmium level, including 190 rice samples, 161 vegetable samples in 2011 and 190 rice samples, 153 vegetable samples in 2014. Urine specimens of residents were collected for the detection of urinary cadmium and creatinine as well as renal dysfunction biomarkers, namely, N-acetyl-beta-D-glucosamidase (NAG) and ß2-microglobulin (ß2-MG), respectively. In 2011 and 2014, Chi-square test was used to investigate the differences of abnormality of cadmium concentration in rice, vegetables and urinary cadmium, ß2-MG, and NAG that were expressed as odds ratio(OR) and 95% confidence intervals (95%CI). RESULTS: In 2011 and 2014, cadmium concentration P50 (P25-P75) in rice was 0.43 (0.17-1.10) mg/kg, and 0.42 (0.20-1.14) mg/kg, respectively (Z=-0.77,P=0.440). In 2011 and 2014, cadmium concentrations P50 (P25-P75) in vegetables were 0.13 (0.07-0.34) mg/kg, and 0.25(0.12-0.59) mg/kg, respectively, with abnormal rates of 38.5%(62/161) and 60.8%(93/153), respectively. In 2014, both average concentration and abnormal rate of cadmium in vegetables were higher than those in 2011 (Z=-4.69, P<0.001 and χ(2)=15.58,P<0.001). Concentrations of urinary cadmium P50 (P25-P75) in high exposed group were 7.90 (3.96-14.91) µg/g creatinine, 8.64 (4.56-17.60) µg/g creatinine in 2011 and 2014, respectively. Contrary to that in 2011, urinary cadmium of high exposed group was significantly increased in 2014 (Z=-2.80, P=0.005). In 2011 and 2014, concentrations of ß2-MG, NAG P50 (P25-P75) were 0.15(0.07-0.29) µg/g creatinine, 0.15 (0.07-0.45) µg/g creatinine, and 7.12 (5.05-10.65) U/g creatinine, 13.55(9.1-19.84) U/g creatinine, respectively, with abnormal rates of 7.5% (23/305), 15.1% (46/305), 8.2% (25/305) , and 33.8% (103/305), respectively. Compared with baseline in 2011, average concentrations of ß2-MG, NAG significantly increased in 2014 (Z=-2.263, P=0.024 and Z=-12.52, P<0.001), and abnormal rates of ß2-MG, NAG were also higher in 2014 (χ(2)=15.61 , P<0.001 and χ(2)=64.72, P<0.001), with odds ratio(OR) of 2.00 (95%CI:1.23-3.24) and 4.12 (95%CI:2.87-5.92). CONCLUSION: Environmental cadmium pollution of crops such as rice and vegetables in survey areas continued to remain high. Body burden of cadmium might kept at sustainably high levels and renal dysfunction was worsened after continuous, long-term cadmium exposure. Our results suggested that NAG might be more sensitive than ß2-MG to serve as an indicator for an individual's future tubular function.

Static and Dynamical Properties of the Spin-1/2 Equilateral Triangular-Lattice Antiferromagnet Ba_{3}CoSb_{2}O_{9}.

We present single-crystal neutron scattering measurements of the spin-1/2 equilateral triangular-lattice antiferromagnet Ba_{3}CoSb_{2}O_{9}. Besides confirming that the Co^{2+} magnetic moments lie in the ab plane for zero magnetic field and then determining all the exchange parameters of the minimal quasi-2D spin Hamiltonian, we provide conclusive experimental evidence of magnon decay through observation of intrinsic line broadening. Through detailed comparisons with the linear and nonlinear spin-wave theories, we also point out that the large-S approximation, which is conventionally employed to predict magnon decay in noncollinear magnets, is inadequate to explain our experimental observation. Thus, our results call for a new theoretical framework for describing excitation spectra in low-dimensional frustrated magnets under strong quantum effects.

Tuning the magnetic exchange via a control of orbital hybridization in Cr(2)(Te(1-x)W(x))O(6).

We report the complex magnetic phase diagram and electronic structure of Cr_{2}(Te_{1-x}W_{x})O_{6} systems. While compounds with different x values possess the same crystal structure, they display different magnetic structures below and above x_{c}=0.7, where both the transition temperature T_{N} and sublattice magnetization (M_{s}) reach a minimum. Unlike many known cases where magnetic interactions are controlled either by injection of charge carriers or by structural distortion induced via chemical doping, in the present case it is achieved by tuning the orbital hybridization between Cr 3d and O 2p orbitals through W 5d states. The result is supported by ab initio electronic structure calculations. Through this concept, we introduce a new approach to tune magnetic and electronic properties via chemical doping.